WorldWideScience

Sample records for macro-scale baroclinic prediction

  1. Diffusiophoresis at the macro-scale

    CERN Document Server

    Mauger, C; Machicoane, N; Bourgoin, M; Cottin-Bizonne, C; Ybert, C; Raynal, F

    2015-01-01

    Diffusiophoresis, a ubiquitous phenomenon which induces particle transport whenever solute gradients are present, was recently put forward in the context of microsystems and shown to strongly impact colloidal transport (from patterning to mixing) at such scales. In the present work, we show experimentally that this nanoscale-rooted mechanism can actually induce changes in the \\textit{macro-scale mixing} of colloids by chaotic advection. Rather than the usual decay of standard deviation of concentration, which is a global parameter, we use different multi-scale tools available for chaotic flows or intermittent turbulent mixing, like concentration spectra, or second and fourth moments of probability density functions of scalar gradients. Not only those tools can be used in open flows (when the mean concentration is not constant), but also they allow for a scale by scale analysis. Strikingly, diffusiophoresis is shown to affect all scales, although more particularly the smallest one, resulting in a change of sca...

  2. Implementation of Microstructural Material Phenomena in Macro Scale Simulations of Forming Processes

    NARCIS (Netherlands)

    Huetink, J.

    2004-01-01

    The paper deals with problems related to full/macro scale simulations of industrial forming processes. Large-scale numerical simulations and virtual modeling are replacing prototypes in order to reduce costs and time. This requires accurate and reliable predictions. To satisfy these requirements, so

  3. Characteristics of soil water retention curve at macro-scale

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Scale adaptable hydrological models have attracted more and more attentions in the hydrological modeling research community, and the constitutive relationship at the macro-scale is one of the most important issues, upon which there are not enough research activities yet. Taking the constitutive relationships of soil water movement--soil water retention curve (SWRC) as an example, this study extends the definition of SWRC at the micro-scale to that at the macro-scale, and aided by Monte Carlo method we demonstrate that soil property and the spatial distribution of soil moisture will affect the features of SWRC greatly. Furthermore, we assume that the spatial distribution of soil moisture is the result of self-organization of climate, soil, ground water and soil water movement under the specific boundary conditions, and we also carry out numerical experiments of soil water movement at the vertical direction in order to explore the relationship between SWRC at the macro-scale and the combinations of climate, soil, and groundwater. The results show that SWRCs at the macro-scale and micro-scale presents totally different features, e.g., the essential hysteresis phenomenon which is exaggerated with increasing aridity index and rising groundwater table. Soil property plays an important role in the shape of SWRC which will even lead to a rectangular shape under drier conditions, and power function form of SWRC widely adopted in hydrological model might be revised for most situations at the macro-scale.

  4. Discrete-element method simulations: from micro to macro scales.

    Science.gov (United States)

    Heyes, D M; Baxter, J; Tüzün, U; Qin, R S

    2004-09-15

    Many liquid systems encountered in environmental science are often complex mixtures of many components which place severe demands on traditional computational modelling techniques. A meso scale description is required to account adequately for their flow behaviour on the meso and macro scales. Traditional techniques of computational fluid dynamics and molecular simulation are not well suited to tackling these systems, and researchers are increasingly turning to a range of relatively new computational techniques that offer the prospect of addressing the factors relevant to multicomponent multiphase liquids on length- and time-scales between the molecular level and the macro scale. In this category, we discuss the off-lattice techniques of 'smooth particle hydrodynamics' (SPH) and 'dissipative particle dynamics' (DPD), and the grid-based techniques of 'lattice gas' and 'lattice Boltzmann' (LB). We highlight the main conceptual and technical features underpinning these methods, their strengths and weaknesses, and provide a few examples of the applications of these techniques that illustrate their utility.

  5. Proposal of a Novel Approach to Developing Material Models for Micro-scale Composites Based on Testing and Modeling of Macro-scale Composites

    Energy Technology Data Exchange (ETDEWEB)

    Siranosian, Antranik Antonio [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Schembri, Philip Edward [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Luscher, Darby Jon [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-04-20

    The Los Alamos National Laboratory's Weapon Systems Engineering division's Advanced Engineering Analysis group employs material constitutive models of composites for use in simulations of components and assemblies of interest. Experimental characterization, modeling and prediction of the macro-scale (i.e. continuum) behaviors of these composite materials is generally difficult because they exhibit nonlinear behaviors on the meso- (e.g. micro-) and macro-scales. Furthermore, it can be difficult to measure and model the mechanical responses of the individual constituents and constituent interactions in the composites of interest. Current efforts to model such composite materials rely on semi-empirical models in which meso-scale properties are inferred from continuum level testing and modeling. The proposed approach involves removing the difficulties of interrogating and characterizing micro-scale behaviors by scaling-up the problem to work with macro-scale composites, with the intention of developing testing and modeling capabilities that will be applicable to the mesoscale. This approach assumes that the physical mechanisms governing the responses of the composites on the meso-scale are reproducible on the macro-scale. Working on the macro-scale simplifies the quantification of composite constituents and constituent interactions so that efforts can be focused on developing material models and the testing techniques needed for calibration and validation. Other benefits to working with macro-scale composites include the ability to engineer and manufacture—potentially using additive manufacturing techniques—composites that will support the application of advanced measurement techniques such as digital volume correlation and three-dimensional computed tomography imaging, which would aid in observing and quantifying complex behaviors that are exhibited in the macro-scale composites of interest. Ultimately, the goal of this new approach is to develop a meso

  6. Macro Scale Independently Homogenized Subcells for Modeling Braided Composites

    Science.gov (United States)

    Blinzler, Brina J.; Goldberg, Robert K.; Binienda, Wieslaw K.

    2012-01-01

    An analytical method has been developed to analyze the impact response of triaxially braided carbon fiber composites, including the penetration velocity and impact damage patterns. In the analytical model, the triaxial braid architecture is simulated by using four parallel shell elements, each of which is modeled as a laminated composite. Currently, each shell element is considered to be a smeared homogeneous material. The commercial transient dynamic finite element code LS-DYNA is used to conduct the simulations, and a continuum damage mechanics model internal to LS-DYNA is used as the material constitutive model. To determine the stiffness and strength properties required for the constitutive model, a top-down approach for determining the strength properties is merged with a bottom-up approach for determining the stiffness properties. The top-down portion uses global strengths obtained from macro-scale coupon level testing to characterize the material strengths for each subcell. The bottom-up portion uses micro-scale fiber and matrix stiffness properties to characterize the material stiffness for each subcell. Simulations of quasi-static coupon level tests for several representative composites are conducted along with impact simulations.

  7. Linking microstructural evolution and macro-scale friction behavior in metals

    Science.gov (United States)

    Argibay, N.; Chandross, M.; Cheng, S.; Michael, J. R.

    2017-03-01

    A correlation is established between the macro-scale friction regimes of metals and a transition between two dominant atomistic mechanisms of deformation. Metals tend to exhibit bi-stable friction behavior -- low and converging or high and diverging. These general trends in behavior are shown to be largely explained using a simplified model based on grain size evolution, as a function of contact stress and temperature, and are demonstrated for pure copper and gold. Specifically, the low friction regime is linked to the formation of ultra-nanocrystalline surface films (10 to 20 nm), driving toward shear accommodation by grain boundary sliding. Above a critical combination of stress and temperature -- demonstrated to be a material property -- shear accommodation transitions to dislocation dominated plasticity and high friction. We utilize a combination of experimental and computational methods to develop and validate the proposed structure-property relationship. This quantitative framework provides a shift from phenomenological to mechanistic and predictive fundamental understanding of friction for crystalline materials, including engineering alloys.

  8. Monitoring of frozen soil hydrology in macro-scale in the Qinghai-Xizang Plateau

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Monitoring of frozen soil hydrology in macro-scale was performed by Chinese and Japanese scientists from 1997 to 1998. Quality measured data were obtained. Measured data on soil moisture and temperature are preliminarily analyzed. Based on profiles of soil temperature and moisture in individual measured sites, intra-annual freezing and melting process of soil is discussed. Maximum frozen and thawed depths and frozen days in various depths are estimated. The work emphasized the spatial distribution on soil temperature and moisture in macro-scale and the effect of topography on conditions of soil water and heat.

  9. Reservoir in Global Water Cycle: Macro Scale Hydrologic Modeling for Water Management

    Science.gov (United States)

    Zhou, T.; Nijssen, B.; Haddeland, I.; Gao, H.; Lettenmaier, D. P.

    2014-12-01

    Man-made reservoirs play a key role in the terrestrial water system. They support purposes, such as irrigation, hydropower generation, and flood control, which can substantially change water fluxes at the land surface and redistribute the storage of surface water in space and time. Although most developed countries have sophisticated observing systems for many variables in the natural surface water cycle, long-term and consistent records that focus on water management and human impacts on the global water cycle are much more limited, and most land surface models ignore water management activities. We describe a continental-scale model of reservoir storage, which is combined with a soil moisture deficit-based irrigation scheme within the Variable Infiltration Capacity (VIC) macro-scale hydrological model to simulate the effects of water management in the major river basins of the world. The model is forced with merged NCEP/NCAR and satellite meteorological data at a spatial resolution of 0.25 degrees latitude-longitude, for the period 1948 to 2010. A total of 167 of the largest reservoirs in the world with a total storage capacity around 3900 km3 (nearly 60% of the global total reservoir storage) are simulated. We successfully predict the monthly reservoir storage time series for most of a set of 23 global reservoirs for which observed storage is available either via in situ or satellite remote sensing measurements. We evaluate, on a continental and global basis, the magnitude of inter-seasonal and inter-annual reservoir storage variations in comparison with other terms in the land surface water cycle, including Snow Water Equivalent (SWE) and soil moisture.

  10. Micro and macro scale electrohydrodynamic enhancement of thin-film evaporation

    Science.gov (United States)

    Darabi, Jafar

    2000-11-01

    Evaporation of thin liquid films has long been recognized as one of the most effective methods of heat removal. As a result, techniques that employ this mechanism have potential for use in many practical applications such as electronic cooling, heat pipes, and process heat exchangers. Demand for high-power density electronics, along with the associated requirements including temperature uniformity and the limitation on maximum temperature, will require the development of new methods of heat removal for these devices. The electrohydrodynamic (EHD) technique offers a promising alternative for the uniform distribution of temperature and the removal of heat at high power levels. These factors directly affect the performance, cost, and reliability of such devices. An experimental investigation was undertaken to study the feasibility of applying the EHD technique for heat transfer enhancement of thin-film evaporation. Macro-scale experiments were conducted on several heat transfer surfaces in both horizontal and vertical orientations and the mechanisms involved in heat transfer enhancement were clarified. For the various heat transfer surface/electrode geometries tested, enhancement factors ranging from 25% to 390% were obtained. The novel concept of EHD-enhanced source level cooling utilizing MEMS and thin-film evaporation was then introduced. The device was designed and fabricated using VLSI fabrication technology. This technology allowed the integration of an active cooling device, a micropump, and temperature sensors into a single chip, greatly facilitating the manufacturing process, increasing the cooling capacity, and improving the thermal management of future high-power density electronics. The results indicate a maximum cooling capacity of 65 W/cm2 and a corresponding pumping head of 250 Pa. This unique microcooling device has high commercialization potential and can pave the way for practical utilization of thin-film evaporation in microelectronics cooling and

  11. Basic studies of baroclinic flows

    Science.gov (United States)

    Miller, Timothy L.; Leslie, Fred W.; Lu, H.-I.; Butler, K. A.

    1993-01-01

    A fully nonlinear 3-dimensional numerical model (GEOSIM), previously developed and validated for several cases of geophysical fluid flow, has been used to investigate the dynamical behavior of laboratory experiments of fluid flows similar to those of the Earth's atmosphere. The phenomena investigated are amplitude vacillation, and the response of the fluid system to uneven heating and cooling. The previous year's work included hysteresis in the transition between axisymmetric and wave flow. Investigation is also continuing of the flows in the Geophysical Fluid Flow Cell (GFFC), a low-gravity Spacelab experiment. Much of the effort in the past year has been spent in validation of the model under a wide range of external parameters including nonlinear flow regimes. With the implementation of a 3-dimensional upwind differencing scheme, higher spectral resolution, and a shorter time step, the model has been found capable of predicting the majority of flow regimes observed in one complete series of baroclinic annulus experiments of Pfeffer and co-workers. Detailed analysis of amplitude vacillation has revealed that the phase splitting described in the laboratory experiments occurs in some but not all cases. Through the use of animation of the models output, a vivid 3-dimensional view of the phase splitting was shown to the audience of the Southeastern Geophysical Fluid Dynamics Conference in March of this year. A study on interannual variability was made using GEOSIM with periodic variations in the thermal forcing. Thus far, the model has not predicted a chaotic behavior as observed in the experiments, although there is a sensitivity in the wavenumber selection to the initial conditions. Work on this subject, and on annulus experiments with non-axisymmetric thermal heating, will continue. The comparison of GEOSIM's predictions will result from the Spacelab 3 GFFC experiments continued over the past year, on a 'back-burner' basis. At this point, the study (in the form of

  12. Handbook of damage mechanics nano to macro scale for materials and structures

    CERN Document Server

    2015-01-01

    This authoritative reference provides comprehensive coverage of the topics of damage and healing mechanics. Computational modeling of constitutive equations is provided as well as solved examples in engineering applications. A wide range of materials that engineers may encounter are covered, including metals, composites, ceramics, polymers, biomaterials, and nanomaterials. The internationally recognized team of contributors employ a consistent and systematic approach, offering readers a user-friendly reference that is ideal for frequent consultation. Handbook of Damage Mechanics: Nano to Macro Scale for Materials and Structures is ideal for graduate students and faculty, researchers, and professionals in the fields of Mechanical Engineering, Civil Engineering, Aerospace Engineering, Materials Science, and Engineering Mechanics.

  13. Three-dimensional macro-scale assessment of regional and temporal wall shear stress characteristics on aortic valve leaflets.

    Science.gov (United States)

    Cao, K; Bukač, M; Sucosky, P

    2016-01-01

    The aortic valve (AV) achieves unidirectional blood flow between the left ventricle and the aorta. Although hemodynamic stresses have been shown to regulate valvular biology, the native wall shear stress (WSS) experienced by AV leaflets remains largely unknown. The objective of this study was to quantify computationally the macro-scale leaflet WSS environment using fluid-structure interaction modeling. An arbitrary Lagrangian-Eulerian approach was implemented to predict valvular flow and leaflet dynamics in a three-dimensional AV geometry subjected to physiologic transvalvular pressure. Local WSS characteristics were quantified in terms of temporal shear magnitude (TSM), oscillatory shear index (OSI) and temporal shear gradient (TSG). The dominant radial WSS predicted on the leaflets exhibited high amplitude and unidirectionality on the ventricularis (TSM>7.50 dyn/cm(2), OSI 325.54 dyn/cm(2) s) but low amplitude and bidirectionality on the fibrosa (TSM 0.38, TSG 0.25). This study provides new insights into the role played by leaflet-blood flow interactions in valvular function and critical hemodynamic stress data for the assessment of the hemodynamic theory of AV disease.

  14. Effects of macro-scale uncertainties on the imaging and automatic manipulation of nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Korayem, M. H., E-mail: hkorayem@iust.ac.ir; Sadeghzadeh, S.; Homayooni, A. [Iran University of Science and Technology, Robotic Research Laboratory, School of Mechanical Engineering (Iran, Islamic Republic of)

    2013-01-15

    The steering, positioning, and fabrication operations in nano scale have been hampered by the uncertainties which come from the macro parts of nano-positioners. Among those uncertainties, the nonlinearities of piezo scanners have the highest contribution, which should be identified and compensated. On the other hand, the recognition of the effects of macro-scale nonlinearities on small-scale dynamics requires the simultaneous consideration of both the macro- and small-scale dynamics. This necessitates the implementation of multi-scale methods. In this article, a fixed interfacial multi-scale method (FIMM) that includes the effects of hysteresis has been used for the computationally and mathematically efficient modeling of nano-positioners. This method presents an improved coupling approach that can be used to study the imaging and manipulation of nanoparticles (from one to several hundred nanometers in diameter) subjected to nonlinear as well as linear positioning schemes. After comparing the applied hysteresis model with some previous experimental works, the dynamics of imaging and automatic manipulation of nanoparticles have been studied and some useful results have been presented. This paper opens a new window to the recognition and compensation of the errors of macro-scale nonlinearities imposed on small-scale dynamics.

  15. Meshing complex macro-scale objects into self-assembling bricks

    Science.gov (United States)

    Hacohen, Adar; Hanniel, Iddo; Nikulshin, Yasha; Wolfus, Shuki; Abu-Horowitz, Almogit; Bachelet, Ido

    2015-07-01

    Self-assembly provides an information-economical route to the fabrication of objects at virtually all scales. However, there is no known algorithm to program self-assembly in macro-scale, solid, complex 3D objects. Here such an algorithm is described, which is inspired by the molecular assembly of DNA, and based on bricks designed by tetrahedral meshing of arbitrary objects. Assembly rules are encoded by topographic cues imprinted on brick faces while attraction between bricks is provided by embedded magnets. The bricks can then be mixed in a container and agitated, leading to properly assembled objects at high yields and zero errors. The system and its assembly dynamics were characterized by video and audio analysis, enabling the precise time- and space-resolved characterization of its performance and accuracy. Improved designs inspired by our system could lead to successful implementation of self-assembly at the macro-scale, allowing rapid, on-demand fabrication of objects without the need for assembly lines.

  16. Impact of climate change on flood characteristics in Brahmaputra basin using a macro-scale distributed hydrological model

    Indian Academy of Sciences (India)

    Shyamal Ghosh; Subashisa Dutta

    2012-06-01

    Being the highest specific discharge river system in the world, the Brahmaputra river experiences a number of long-duration flood waves during the monsoon season annually. In order to assess the flood characteristics at the basin and tributary scales, a physically based macro-scale distributed hydrological model (DHM) has been calibrated and validated for 9 wet years. The model performance has been evaluated in terms of prediction of the flood characteristics such as peak discharge, flood duration, arrival time of flood wave, timing of the peak flow and number of flood waves per season. Future changes in the flood wave characteristics of the basin have been evaluated using the validated model with bias-corrected future-projected meteorological scenario from a regional climate model (RCM). Likelihood analysis of the simulated flow time series reveals that significant increase in both peak discharge and flood duration is expected for both the pre-monsoonal and monsoonal seasons in the basin, but the number of flood waves per season would be reduced. Under the projected climate change scenario, it is expected that there will be more catastrophic floods in the basin.

  17. A macro-scale perspective on within-farm management: how climate and topography alter the effect of farming practices.

    Science.gov (United States)

    Amano, Tatsuya; Kusumoto, Yoshinobu; Okamura, Hiroshi; Baba, Yuki G; Hamasaki, Kenji; Tanaka, Koichi; Yamamoto, Shori

    2011-12-01

    Organic farming has the potential to reverse biodiversity loss in farmland and benefit agriculture by enhancing ecosystem services. Although the mixed success of organic farming in enhancing biodiversity has been attributed to differences in taxa and landscape context, no studies have focused on the effect of macro-scale factors such as climate and topography. This study provides the first assessment of the impact of macro-scale factors on the effectiveness of within-farm management on biodiversity, using spiders in Japan as an example. A multilevel modelling approach revealed that reducing pesticide applications increases spider abundance, particularly in areas with high precipitation, which were also associated with high potential spider abundance. Using the model we identified areas throughout Japan that can potentially benefit from organic farming. The alteration of local habitat-abundance relations by macro-scale factors could explain the reported low spatial generality in the effects of organic farming and patterns of habitat association.

  18. Investigation of Micro- and Macro-Scale Transport Processes for Improved Fuel Cell Performance

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Wenbin

    2015-02-05

    This report documents the work performed by General Motors (GM) under the Cooperative agreement No. DE-EE0000470, “Investigation of Micro- and Macro-Scale Transport Processes for Improved Fuel Cell Performance,” in collaboration with the Penn State University (PSU), University of Tennessee Knoxville (UTK), Rochester Institute of Technology (RIT), and University of Rochester (UR) via subcontracts. The overall objectives of the project are to investigate and synthesize fundamental understanding of transport phenomena at both the macro- and micro-scales for the development of a down-the-channel model that accounts for all transport domains in a broad operating space. GM as a prime contractor focused on cell level experiments and modeling, and the Universities as subcontractors worked toward fundamental understanding of each component and associated interface.

  19. Investigation of Micro- and Macro-Scale Transport Processes for Improved Fuel Cell Performance

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Wenbin [General Motors LLC, Pontiac, MI (United States)

    2014-08-29

    This report documents the work performed by General Motors (GM) under the Cooperative agreement No. DE-EE0000470, “Investigation of Micro- and Macro-Scale Transport Processes for Improved Fuel Cell Performance,” in collaboration with the Penn State University (PSU), University of Tennessee Knoxville (UTK), Rochester Institute of Technology (RIT), and University of Rochester (UR) via subcontracts. The overall objectives of the project are to investigate and synthesize fundamental understanding of transport phenomena at both the macro- and micro-scales for the development of a down-the-channel model that accounts for all transport domains in a broad operating space. GM as a prime contractor focused on cell level experiments and modeling, and the Universities as subcontractors worked toward fundamental understanding of each component and associated interface.

  20. Toward Zero Micro/Macro-Scale Wear Using Periodic Nano-Layered Coatings.

    Science.gov (United States)

    Penkov, Oleksiy V; Devizenko, Alexander Yu; Khadem, Mahdi; Zubarev, Evgeniy N; Kondratenko, Valeriy V; Kim, Dae-Eun

    2015-08-19

    Wear is an important phenomenon that affects the efficiency and life of all moving machines. In this regard, extensive efforts have been devoted to achieve the lowest possible wear in sliding systems. With the advent of novel materials in recent years, technology is moving toward realization of zero wear. Here, we report on the development of new functional coatings comprising periodically stacked nanolayers of amorphous carbon and cobalt that are extremely wear resistant at the micro and macro scale. Because of their unique structure, these coatings simultaneously provide high elasticity and ultrahigh shear strength. As a result, almost zero wear was observed even after one million sliding cycles without any lubrication. The wear rate was reduced by 8-10-fold compared with the best previously reported data on extremely low wear materials.

  1. Digital holographic setups for phase object measurements in micro and macro scale

    Directory of Open Access Journals (Sweden)

    Lédl Vít

    2015-01-01

    Full Text Available The measurement of properties of so called phase objects is being solved for more than one Century starting probably with schlieren technique 1. Classical interferometry served as a great measurement tool for several decades and was replaced by holographic interferometry, which disposes with many benefits when compared to classical interferometry. Holographic interferometry undergone an enormous development in last decade when digital holography has been established as a standard technique and most of the drawbacks were solved. The paper deals with scope of the huge applicability of digital holographic interferometry in heat and mass transfer measurement from micro to macro scale and from simple 2D measurement up to complex tomographic techniques. Recently the very complex experimental setups are under development in our labs combining many techniques leading to digital holographic micro tomography methods.

  2. Predator-prey interactions as macro-scale drivers of species diversity in mammals

    DEFF Research Database (Denmark)

    Sandom, Christopher James; Sandel, Brody Steven; Dalby, Lars

    mechanistic drivers of mammal species richness at macro-scales for two trophic levels: predators and prey. To disentangle biotic (i.e. functional predator-prey interactions) from abiotic (i.e. environmental) and bottom-up from top-down determinants we considered three hypotheses: 1) environmental factors......-down). We gathered distributional range, mass and diet data for 4,091 terrestrial mammal species, excluding bats. Species richness maps were created for predators and prey and structural equation modelling was used to test the three hypotheses at continental and global scales. We also explored...... the importance of functional trait composition by analyzing richness of large and small mass categories for prey (division at 10 kg) and predators (division at 21.5 kg). Results/Conclusions Mammal species richness increased from the poles to the equator, supporting the classic latitudinal richness gradient...

  3. Reduced Baroclinicity During Martian Global Dust Storms

    Science.gov (United States)

    Battalio, Joseph; Szunyogh, Istvan; Lemmon, Mark

    2015-11-01

    The eddy kinetic energy equation is applied to the Mars Analysis Correction Data Assimilation (MACDA) dataset during the pre-winter solstice period for the northern hemisphere of Mars. Traveling waves are triggered by geopotential flux convergence, grow baroclinically, and decay barotropically. Higher optical depth increases the static stability, which reduces vertical and meridional heat fluxes. Traveling waves during a global dust storm year develop a mixed baroclinic/barotropic growth phase before decaying barotropically. Baroclinic energy conversion is reduced during the global dust storm, but eddy intensity is undiminished. Instead, the frequency of storms is reduced due to a stabilized vertical profile.

  4. From micro-scale 3D simulations to macro-scale model of periodic porous media

    Science.gov (United States)

    Crevacore, Eleonora; Tosco, Tiziana; Marchisio, Daniele; Sethi, Rajandrea; Messina, Francesca

    2015-04-01

    In environmental engineering, the transport of colloidal suspensions in porous media is studied to understand the fate of potentially harmful nano-particles and to design new remediation technologies. In this perspective, averaging techniques applied to micro-scale numerical simulations are a powerful tool to extrapolate accurate macro-scale models. Choosing two simplified packing configurations of soil grains and starting from a single elementary cell (module), it is possible to take advantage of the periodicity of the structures to reduce the computation costs of full 3D simulations. Steady-state flow simulations for incompressible fluid in laminar regime are implemented. Transport simulations are based on the pore-scale advection-diffusion equation, that can be enriched introducing also the Stokes velocity (to consider the gravity effect) and the interception mechanism. Simulations are carried on a domain composed of several elementary modules, that serve as control volumes in a finite volume method for the macro-scale method. The periodicity of the medium involves the periodicity of the flow field and this will be of great importance during the up-scaling procedure, allowing relevant simplifications. Micro-scale numerical data are treated in order to compute the mean concentration (volume and area averages) and fluxes on each module. The simulation results are used to compare the micro-scale averaged equation to the integral form of the macroscopic one, making a distinction between those terms that could be computed exactly and those for which a closure in needed. Of particular interest it is the investigation of the origin of macro-scale terms such as the dispersion and tortuosity, trying to describe them with micro-scale known quantities. Traditionally, to study the colloidal transport many simplifications are introduced, such those concerning ultra-simplified geometry that usually account for a single collector. Gradual removal of such hypothesis leads to a

  5. The driving of baroclinic anomalies at different timescales

    OpenAIRE

    Blanco-Fuentes, Javier; Zurita-Gotor, Pablo

    2011-01-01

    This work investigates the internal variability of zonal-mean baroclinicity over the Southern Hemisphere midlatitudes. The first two leading modes describe a meridional baroclinicity shift and a sharpening/broadening of baroclinicity, with the shift becoming more dominant at low frequency. The lifecycles of the baroclinic anomalies, estimated by means of lagged regression analysis, are qualitatively different depending on the frequency range. At high frequency, the zonal-mean baroclinicity si...

  6. Detecting benzoyl peroxide in wheat flour by line-scan macro-scale Raman chemical imaging

    Science.gov (United States)

    Qin, Jianwei; Kim, Moon S.; Chao, Kuanglin; Gonzalez, Maria; Cho, Byoung-Kwan

    2017-05-01

    Excessive use of benzoyl peroxide (BPO, a bleaching agent) in wheat flour can destroy flour nutrients and cause diseases to consumers. A macro-scale Raman chemical imaging method was developed for direct detection of BPO mixed in the wheat flour. A 785 nm line laser was used in a line-scan Hyperspectral Raman imaging system. Raman images were collected from wheat flour mixed with BPO at eight concentrations (w/w) from 50 to 6,400 ppm. A sample holder (150×100×2 mm3) was used to present a thin layer (2 mm thick) of the powdered sample for image acquisition. A baseline correction method was used to correct the fluctuating fluorescence signals from the wheat flour. To isolate BPO particles from the flour background, a simple thresholding method was applied to the single-band fluorescence-free images at a unique Raman peak wavenumber (i.e., 1001 cm-1) preselected for the BPO detection. Chemical images were created to detect and map the BPO particles. Limit of detection for the BPO was estimated in the order of 50 ppm, which is on the same level with regulatory standards.

  7. Construction of Modular Hydrogel Sheets for Micropatterned Macro-scaled 3D Cellular Architecture.

    Science.gov (United States)

    Son, Jaejung; Bae, Chae Yun; Park, Je-Kyun

    2016-01-11

    Hydrogels can be patterned at the micro-scale using microfluidic or micropatterning technologies to provide an in vivo-like three-dimensional (3D) tissue geometry. The resulting 3D hydrogel-based cellular constructs have been introduced as an alternative to animal experiments for advanced biological studies, pharmacological assays and organ transplant applications. Although hydrogel-based particles and fibers can be easily fabricated, it is difficult to manipulate them for tissue reconstruction. In this video, we describe a fabrication method for micropatterned alginate hydrogel sheets, together with their assembly to form a macro-scale 3D cell culture system with a controlled cellular microenvironment. Using a mist form of the calcium gelling agent, thin hydrogel sheets are easily generated with a thickness in the range of 100 - 200 µm, and with precise micropatterns. Cells can then be cultured with the geometric guidance of the hydrogel sheets in freestanding conditions. Furthermore, the hydrogel sheets can be readily manipulated using a micropipette with an end-cut tip, and can be assembled into multi-layered structures by stacking them using a patterned polydimethylsiloxane (PDMS) frame. These modular hydrogel sheets, which can be fabricated using a facile process, have potential applications of in vitro drug assays and biological studies, including functional studies of micro- and macrostructure and tissue reconstruction.

  8. Direct Measurements of the Baroclinic Instability in the Ocean

    Science.gov (United States)

    Sadek, Mahmoud; Aluie, Hussein; Hecht, Matthew; Vallis, Geoffrey

    2016-11-01

    The ocean is mechanically driven by wind and buoyancy at the surface which produce sloping isopycnals with a reservoir of available potential energy (APE). Large scale APE can be converted to kinetic energy via the baroclinic instability, which produces mesoscale eddies. Mesoscale eddies are ubiquitous in mid- and high-latitudes, and play a primary role in determining the strength and trajectories of currents and in generating intrinsic climate variability. The widespread belief that mesoscale eddies are generated through baroclinic instability is based on general accord between observations and linear stability analysis and the predicted behavior of nonlinear models. However, these models are unable to give us quantitative evidence of the extent to which the instability is responsible for eddy generation at various locations in the ocean. To this end, we implement a new coarse-graining framework, recently developed to study flow on a sphere, to directly analyze the baroclinic instability as a function of scale and geographic location, and implement it using strongly eddying high-resolution simulations in the North Atlantic and in the Southern Ocean. The results give us new information about location and intensity of the instability in both physical and spectral space. Partial support was provided by National Science Foundation (NSF) Grant OCE-1259794, US Department of Energy (US DOE) Grant DE-SC0014318, and the LANL LDRD program through Project Number 20150568ER.

  9. Macro-Scale Correction of Precipitation Undercatch in the Midwest/Great Lakes Region

    Science.gov (United States)

    Chiu, C. M.; Hamlet, A. F.

    2015-12-01

    Precipitation gauge undercatch is a serious problem in the context of using observed meteorological data sets for hydrologic modeling studies in regions with cold winters, such as the Midwest. Attention to this matter is urgently needed to support hydroclimatological research efforts in the region. To support hydrologic modeling studies, a new hybrid gridded meteorological dataset at 1/16 degree resolution based on data from CO-OP station records, the U. S. Historical Climatology Network, the Historical Canadian Climate Database, and Precipitation Regression on Independent Slopes Method has been assembled over the Great Lakes and Midwest regions from 1915-2013 at daily time step. Preliminary hydrologic simulations results using the Variable Infiltration Capacity hydrology model with this hybrid gridded meteorological dataset showed that precipitation gauge undercatch was a very significant issue throughout the region, especially for winter snowfall and simulated streamflow, which were both grossly underpredicted. Correction of primary CO-OP station data is generally infeasible due to missing station meta data and lack of local-scale wind speed measurements. Instead, macro-scale post processing techniques were developed to adjust the regridded precipitation product from CO-OP station records from 1950-2013 forwards, accounting for undercatch as a function of regridded wind speed simulations obtained from NCAR Reanalysis. Comparisons of simulated and observed streamflow over seven river basins in the Midwest were used to evaluate the datasets constructed using different combinations of meteorological station inputs, with and without undercatch corrections. The comparisons show promise in producing corrected precipitation data sets from 1950-2013 for hydrologic modeling studies, with substantial improvements in streamflow simulation from the uncalibrated VIC model when gauge undercatch corrections are included.

  10. Quantum manifestation of systems on the macro-scale – the concept of transition state and transition amplitude wave

    Indian Academy of Sciences (India)

    Ram K Varma

    2007-06-01

    Quantum effects which have usually been associated with micro-scale phenomena can also arise on the macro-scale in situations other than the well-known macro-quantum phenomena of superconductivity and superfluidity. Such situations have been shown here to arise in processes involving inelastic scattering with bound or partially bound systems (not bound in all degrees of freedom), and the macro-quantum behaviour is associated with the state of the total system in transition in the process of scattering. Such a state is designated as a `transition-state'. It is pointed out that we have already observed such manifestations for a particular system, the charged particles in a magnetic field where interference effects involving macro-scale matter waves along the magnetic field have been reported [R K Varma et al, Phys. Rev. E65, 026503 (2002)].

  11. Baroclinic-Barotropic Interaction in Teleconnections

    Science.gov (United States)

    Ji, Xuan

    Teleconnections are remote impacts from one location to another, which are transmitted through planetary-scale wave motions, e.g., Rossby waves. Teleconnections can be forced by tropical heat sources, for example, El Nino/Southern Oscillation (ENSO), and result in many societally important impacts in remote ocean basins and continents. It is thus important to understand the complex pathway and wave dynamics in teleconnections. This dissertation discusses the role of baroclinic-barotropic interaction in three different aspects of atmospheric teleconnections. The first major question addressed is what mechanisms control the interhemispheric teleconnections from tropical heat sources. These are investigated using an intermediate complexity model [a Quasi-equilibrium Tropical Circulation Model (QTCM)] and a simple linear two-level model with dry dynamics. Illustrating the interhemispheric teleconnection process with an Atlantic Warm Pool principal case, the heat source directly excites a baroclinic response that spreads across the equator. Three processes involving baroclinic-barotropic interactions---shear advection, surface drag, and vertical advection---then force a cross-equatorial barotropic Rossby wave response. An analysis of these processes in QTCM simulations indicates that: (1) shear advection has a pattern that roughly coincides with the baroclinic signal in the tropics and subtropics; (2) surface drag has large amplitude and spatial extent, and can be very effective in forcing barotropic motions around the globe; (3) vertical advection has a significant contribution locally and remotely where large vertical motions and vertical shear occur. A simple model is modified to perform experiments in which each of these three mechanisms may be included or omitted. By adding surface drag and vertical advection, and comparing each to shear advection, the effects of the three mechanisms on the generation and propagation of the barotropic Rossby waves are shown to be

  12. Baroclinic flow and the Lorenz-84 model

    NARCIS (Netherlands)

    Veen, Lennaert van

    2002-01-01

    The bifurcation diagram of a truncation to six degrees of freedom of the equations for quasi-geostrophic, baroclinic flow is investigated. Period doubling cascades and Shil'nikov bifurcations lead to chaos in this model. The low dimension of the chaotic attractor suggests the possibility to reduce t

  13. Baroclinic stationary waves in aquaplanet models

    CERN Document Server

    Zappa, Giuseppe; Navarra, Antonio; 10.1175/2011JAS3573.1

    2011-01-01

    An aquaplanet model is used to study the nature of the highly persistent low frequency waves that have been observed in models forced by zonally symmetric boundary conditions. Using the Hayashi spectral analysis of the extratropical waves, we find that a quasi-stationary (QS) wave five belongs to a wave packet obeying a well defined dispersion relation with eastward group velocity. The components of the dispersion relation with k>5 baroclinically convert eddy available potential energy into eddy kinetic energy, while those with k<5 are baroclinically neutral. In agreement with the Green's model of baroclinic instability, the wave five is weakly unstable, and the inverse energy cascade, which had been previously proposed as a main forcing for this type of waves, only acts as a positive feedback on its predominantly baroclinic energetics. The QS wave is reinforced by a phase lock to an analogous pattern in the tropical convection, which provides further amplification to the wave. We also find that the Pedlos...

  14. Implementation and adaptation of a macro-scale methodology to calculate direct economic losses

    Science.gov (United States)

    Natho, Stephanie; Thieken, Annegret

    2017-04-01

    forestry sector. Furthermore overheads are proposed to include costs of housing content as well as the overall costs of public infrastructure, one of the most important damage sectors. All constants considering sector specific mean sizes or construction costs were adapted. Loss ratios were adapted for each event. Whereas the original UNISDR method over- und underestimates the losses of the tested events, the adapted method is able to calculate losses in good accordance for river floods, hail storms and storms. For example, for the 2013-flood economic losses of EUR 6.3 billion were calculated (UNISDR EUR 0.85 billion, documentation EUR 11 billion). For the hail storms in 2013 the calculated EUR 3.6 billion overestimate the documented losses of EUR 2.7 billion less than the original UNISDR approach with EUR 5.2 billion. Only for flash floods, where public infrastructure can account for more than 90% of total losses, the method is absolutely not applicable. The adapted methodology serves as a good starting point for macro-scale loss estimations by accounting for the most important damage sectors. By implementing this approach into damage and event documentation and reporting standards, a consistent monitoring according to the SFDRR could be achieved.

  15. Deep ocean influence on upper ocean baroclinic instability saturation

    CERN Document Server

    Olascoaga, M J; Sheinbaum, J

    2003-01-01

    In this paper we extend earlier results regarding the effects of the lower layer of the ocean (below the thermocline) on the baroclinic instability within the upper layer (above the thermocline). We confront quasigeostrophic baroclinic instability properties of a 2.5-layer model with those of a 3-layer model with a very thick deep layer, which has been shown to predict spectral instability for basic state parameters for which the 2.5-layer model predicts nonlinear stability. We compute and compare maximum normal-mode perturbation growth rates, as well as rigorous upper bounds on the nonlinear growth of perturbations to unstable basic states, paying particular attention to the region of basic state parameters where the stability properties of the 2.5- and 3-layer model differ substantially. We found that normal-mode perturbation growth rates in the 3-layer model tend to maximize in this region. We also found that the size of state space available for eddy-amplitude growth tends to minimize in this same region....

  16. Baroclinic Instability on Hot Extrasolar Planets

    CERN Document Server

    Polichtchouk, Inna

    2012-01-01

    We investigate baroclinic instability in flow conditions relevant to hot extrasolar planets. The instability is important for transporting and mixing heat, as well as for influencing large-scale variability on the planets. Both linear normal mode analysis and non-linear initial value calculations are carried out -- focusing on the freely-evolving, adiabatic situation. Using a high-resolution general circulation model (GCM) which solves the traditional primitive equations, we show that large-scale jets similar to those observed in current GCM simulations of hot extrasolar giant planets are likely to be baroclinically unstable on a timescale of few to few tens of planetary rotations, generating cyclones and anticyclones that drive weather systems. The growth rate and scale of the most unstable mode obtained in the linear analysis are in qualitative, good agreement with the full non-linear calculations. In general, unstable jets evolve differently depending on their signs (eastward or westward), due to the chang...

  17. Vorticity production through rotation, shear and baroclinicity

    OpenAIRE

    Del Sordo, Fabio; Brandenburg, Axel

    2010-01-01

    In the absence of rotation and shear, and under the assumption of constant temperature or specific entropy, purely potential forcing by localized expansion waves is known to produce irrotational flows that have no vorticity. Here we study the production of vorticity under idealized conditions when there is rotation, shear, or baroclinicity, to address the problem of vorticity generation in the interstellar medium in a systematic fashion. We use three-dimensional periodic box numerical simulat...

  18. Semi-automated image processing system for micro- to macro-scale analysis of immunohistopathology: application to ischemic brain tissue.

    Science.gov (United States)

    Wu, Chunyan; Zhao, Weizhao; Lin, Baowan; Ginsberg, Myron D

    2005-04-01

    Immunochemical staining techniques are commonly used to assess neuronal, astrocytic and microglial alterations in experimental neuroscience research, and in particular, are applied to tissues from animals subjected to ischemic stroke. Immunoreactivity of brain sections can be measured from digitized immunohistology slides so that quantitative assessment can be carried out by computer-assisted analysis. Conventional methods of analyzing immunohistology are based on image classification techniques applied to a specific anatomic location at high magnification. Such micro-scale localized image analysis limits one for further correlative studies with other imaging modalities on whole brain sections, which are of particular interest in experimental stroke research. This report presents a semi-automated image analysis method that performs convolution-based image classification on micro-scale images, extracts numerical data representing positive immunoreactivity from the processed micro-scale images and creates a corresponding quantitative macro-scale image. The present method utilizes several image-processing techniques to cope with variances in intensity distribution, as well as artifacts caused by light scattering or heterogeneity of antigen expression, which are commonly encountered in immunohistology. Micro-scale images are composed by a tiling function in a mosaic manner. Image classification is accomplished by the K-means clustering method at the relatively low-magnification micro-scale level in order to increase computation efficiency. The quantitative macro-scale image is suitable for correlative analysis with other imaging modalities. This method was applied to different immunostaining antibodies, such as endothelial barrier antigen (EBA), lectin, and glial fibrillary acidic protein (GFAP), on histology slides from animals subjected to middle cerebral artery occlusion by the intraluminal suture method. Reliability tests show that the results obtained from

  19. A Novel Formulation of Baroclinic Rotational Equilibria

    CERN Document Server

    Yasutake, Nobutoshi

    2014-01-01

    We have developed a new formulation to obtain self-gravitating, axisymmetric configurations in permanent rotation. It is applicable not only to barotropic equations of state but also to baroclinic ones, for which angular momentum distributions are not cylindrical. The formulation is based on the Lagrangian variational principle. Some test calculations are presented, in which we have achieved an error of $O(10^{-4})$ in the Virial relation. We believe that this method could be a major break-through in stellar evolution theory, in which it is a common practice that rotation is included only approximately in one dimensional models.

  20. Wind-Forced Baroclinic Beta-Plumes

    Science.gov (United States)

    Belmadani, A.; Maximenko, N. A.; Melnichenko, O.; Schneider, N.; Di Lorenzo, E.

    2011-12-01

    A planetary beta-plume is a classical example of oceanic circulation induced by a localized vorticity source or sink that allows an analytical description in simplistic cases. Its barotropic structure is a zonally-elongated, gyre-like cell governed by the Sverdrup circulation on the beta-plane. The dominant zonal currents, found west of the source/sink, are often referred to as zonal jets. This simple picture describes the depth-integrated flow. Previous studies have investigated beta-plumes in a reduced-gravity framework or using other simple models with a small number of vertical layers, thereby lacking representation of the vertical structure. In addition, most previous studies use a purely linear regime without considering the role of eddies. However, these jets are often associated with strong lateral shear that makes them unstable under increased forcing. The circulation in such a nonlinear regime may involve eddy-mean flow interactions, which modify the time-averaged circulation. Here, the baroclinic structures of linear and nonlinear wind-forced beta-plumes are studied using a continuously-stratified, primitive equation, eddy-permitting ocean model (ROMS). The model is configured in an idealized rectangular domain for the subtropical ocean with a flat bottom. The surface wind forcing is a steady anticyclonic Gaussian wind vortex, which provides a localized vorticity source in the center of the domain. The associated wind stress curl and Ekman pumping comprise downwelling in the vortex center surrounded by a ring of weaker upwelling. Under weak forcing, the simulated steady-state circulation corresponds well with a theoretical linear beta-plume. While its depth-integrated transport exhibits a set of zonal jets, consistent with Sverdrup theory, the baroclinic structure of the plume is remarkably complex. Relatively fast westward decay of the surface currents occurs simultaneously with the deepening of the lower boundary of the plume. This deepening suggests

  1. The Role of the Halted Baroclinic Mode at the Central Equatorial Pacific in El Ni(n)o Event

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The role of halted "baroclinic modes" in the central equatorial Pacific is analyzed. It is found that dominant anomaly signals corresponding to "baroclinic modes" occur in the upper layer of the equatorial Pacific, in a two-and-a-half layer oceanic model, in assimilated results of a simple OGCM and in the ADCP observation of TAO. A second "baroclinic mode" is halted in the central equatorial Pacific corresponding to a positive SST anomaly while the first "baroclinic mode" propagates eastwards in the eastern equatorial Pacific. The role of the halted second "baroclinic mode" in the central equatorial Pacific is explained by a staged ocean-atmosphere interaction mechanism in the formation of El Ni(n)o: the westerly bursts in boreal winter over the western equatorial Pacific generate the halted second "baroclinic mode" in the central equatorial Pacific, leading to the increase of heat content and temperature in the upper layer of the central Pacific which induces the shift of convection from over the western equatorial Pacific to the central equatorial Pacific; another wider, westerly anomaly burst is induced over the western region of convection above the central equatorial Pacific and the westerly anomaly burst generates the first "baroclinic mode"propagating to the eastern equatorial Pacific, resulting in a warm event in the eastern equatorial Pacific.The mechanism presented in this paper reveals that the central equatorial Pacific is a key region in detecting the possibility of ENSO and, by analyzing TAO observation data of ocean currents and temperature in the central equatorial Pacific, in predicting the coming of an El Ni(n)o several months ahead.

  2. Baroclinic Channel Model in Fluid Dynamics

    Directory of Open Access Journals (Sweden)

    Kharatti Lal

    2016-02-01

    Full Text Available A complex flow structure is studied using a 2-dimentional baroclinic channel model Unsteady Navier - stokes equation coupled with equation of thermal energy ,salinity and the equation of state are implemented .System closure is achieved through a modified Prandtl, s mixing length formulation of turbulence dissipation The model is applied in a region where the fluid flow is effected by various forcing equation .In this case ,flow is estuarine region affected by diurnal tide and the fresh water inflow in to the estuary and a submerged structure is considered giving possible insight in to stress effects on submerged structure .the result show that in the time evolution of the vertical velocity along downstream edge changes sign from negative to positive .as the dike length increases the primary cell splits and flow becomes turbulent du e to the non-linear effect caused by the dike .these are found to agree favourably with result published in the open literature.

  3. Vorticity production through rotation, shear and baroclinicity

    CERN Document Server

    Del Sordo, Fabio

    2010-01-01

    In the absence of rotation and shear, and under the assumption of constant temperature or specific entropy, purely potential forcing by localized expansion waves is known to produce irrotational flows that have no vorticity. Here we study the production of vorticity under idealized conditions when there is rotation, shear, or baroclinicity, to address the problem of vorticity generation in the interstellar medium in a systematic fashion. We use three-dimensional periodic box numerical simulations to investigate the various effects in isolation. We find that for slow rotation, vorticity production in an isothermal gas is small in the sense that the ratio of the root-mean-square values of vorticity and velocity is small compared with the wavenumber of the energy carrying motions. For Coriolis numbers above a certain level, vorticity production saturates at a value where the aforementioned ratio becomes comparable with the wavenumber of the energy carrying motions. Shear also raises the vorticity production, but...

  4. Macro-Scale Patterns in Upwelling/Downwelling Activity at North American West Coast

    Science.gov (United States)

    Saldívar-Lucio, Romeo; Di Lorenzo, Emanuele; Nakamura, Miguel; Villalobos, Héctor; Lluch-Cota, Daniel; Del Monte-Luna, Pablo

    2016-01-01

    The seasonal and interannual variability of vertical transport (upwelling/downwelling) has been relatively well studied, mainly for the California Current System, including low-frequency changes and latitudinal heterogeneity. The aim of this work was to identify potentially predictable patterns in upwelling/downwelling activity along the North American west coast and discuss their plausible mechanisms. To this purpose we applied the min/max Autocorrelation Factor technique and time series analysis. We found that spatial co-variation of seawater vertical movements present three dominant low-frequency signals in the range of 33, 19 and 11 years, resembling periodicities of: atmospheric circulation, nodal moon tides and solar activity. Those periodicities might be related to the variability of vertical transport through their influence on dominant wind patterns, the position/intensity of pressure centers and the strength of atmospheric circulation cells (wind stress). The low-frequency signals identified in upwelling/downwelling are coherent with temporal patterns previously reported at the study region: sea surface temperature along the Pacific coast of North America, catch fluctuations of anchovy Engraulis mordax and sardine Sardinops sagax, the Pacific Decadal Oscillation, changes in abundance and distribution of salmon populations, and variations in the position and intensity of the Aleutian low. Since the vertical transport is an oceanographic process with strong biological relevance, the recognition of their spatio-temporal patterns might allow for some reasonable forecasting capacity, potentially useful for marine resources management of the region. PMID:27893826

  5. Baroclinic stationary waves in aquaplanet models

    Science.gov (United States)

    Lucarini, V.; Zappa, G.

    2012-04-01

    An aquaplanet model is used to study the nature of the highly persistent low frequency waves that have been observed in models forced by zonally symmetric boundary conditions. Using the Hayashi spectral analysis of the extratropical waves, we find that a quasi-stationary (QS) wave five belongs to a wave packet obeying a well defined dispersion relation with eastward group velocity. The components of the dispersion relation with k>5 baroclinically convert eddy available potential energy into eddy kinetic energy, while those with kinverse energy cascade, which had been previously proposed as a main forcing for this type of waves, only acts as a positive feedback on its predominantly baroclinic energetics. The QS wave is reinforced by a phase lock to an analogous pattern in the tropical convection, which provides further amplification to the wave. We also find that the Pedlosky bounds on the phase speed of unstable waves provide guidance in explaining the latitudinal structure of the energy conversion, which is shown to be more enhanced where the zonal westerly surface wind is weaker. The wave energy is then trapped in the wave guide created by the upper tropospheric jet stream. In agreement with Green's theory, as the equator to pole SST difference is reduced the stationary marginally stable component shifts toward higher wavenumbers, while the wave five becomes neutral and westward propagating. Some properties of the aquaplanet QS waves are found in interesting agreement with a low frequency wave observed by Salby (1982) in the southern hemisphere DJF, so that this perspective on low frequency variability might be, apart from its value in terms of basic geophysical fluid dynamics, of specific interest for studying the Earth's atmosphere.

  6. Detecting and modelling structures on the micro and the macro scales: Assessing their effects on solute transport behaviour

    Science.gov (United States)

    Haslauer, C. P.; Bárdossy, A.; Sudicky, E. A.

    2017-09-01

    This paper demonstrates quantitative reasoning to separate the dataset of spatially distributed variables into different entities and subsequently characterize their geostatistical properties, properly. The main contribution of the paper is a statistical based algorithm that matches the manual distinction results. This algorithm is based on measured data and is generally applicable. In this paper, it is successfully applied at two datasets of saturated hydraulic conductivity (K) measured at the Borden (Canada) and the Lauswiesen (Germany) aquifers. The boundary layer was successfully delineated at Borden despite its only mild heterogeneity and only small statistical differences between the divided units. The methods are verified with the more heterogeneous Lauswiesen aquifer K data-set, where a boundary layer has previously been delineated. The effects of the macro- and the microstructure on solute transport behaviour are evaluated using numerical solute tracer experiments. Within the microscale structure, both Gaussian and non-Gaussian models of spatial dependence of K are evaluated. The effects of heterogeneity both on the macro- and the microscale are analysed using numerical tracer experiments based on four scenarios: including or not including the macroscale structures and optimally fitting a Gaussian or a non-Gaussian model for the spatial dependence in the micro-structure. The paper shows that both micro- and macro-scale structures are important, as in each of the four possible geostatistical scenarios solute transport behaviour differs meaningfully.

  7. Meso-Scale Experimental & Numerical Studies for Predicting Macro-scale Performance of Advanced Reactive Materials (ARMs)

    Science.gov (United States)

    2015-04-01

    develop and implement the techniques to quantify and mathematically represent such differences in the spatial arrangements; to formulate approaches to...two-point correlation functions are mathematically constrained to be equal at 0, the t-test fails to reject the hypothesis that the two functions are...2002). 8 S.H. Fisher and M.C. Grubelich, 32ndAIAA/ASME/SAE/ASEE Jointt Propulsion conference, Lake Buena Vista , FL, July 1-3, 1996, SANDIA Report

  8. Damage Prediction Using Several Types of Macro-scale Damage Models in Different Cold Wire Production Lines

    OpenAIRE

    Cao, Trong-Son; Montmitonnet, Pierre; Bouchard, Pierre-Olivier; Bobadilla, Christian; Vachey, Christophe

    2014-01-01

    International audience; The purpose of the present paper is to show how and to what extent the introduction of refined, shear sensitive models improves on previous ones, based on triaxiality only, for the phenomenological description of ductile damage in bulk cold metal forming processes. Wire-drawing and wire rolling are taken as examples. A set of mechanical tests has been conducted: round bar tension, notched bar tension, plane strain tension, and torsion for pure shear deformation. Both c...

  9. A linear analysis of the transition curve for the baroclinic annulus

    Science.gov (United States)

    Miller, T. L.; Gall, R. L.

    1983-01-01

    A primitive equation linear model is shown to be capable of quantitatively predicting the neutral curve for a baroclinic annulus. Flows unstable to small nonaxisymmetric perturbations are assumed to lie on the nonaxisymmetric side of a transition curve, while the stable flows are on the axisymmetric side. The stability in the presence of perturbations is tested with linearized hydrostatic primitive equations. Attention is given to the fastest growing eigenmodes, demonstrating that the linear and nonlinear wave have similar structures at a particular point in the nonaxisymmetric regime. All the waves are similar to the Eddy wave except at the extreme to the transition curve, where the waves maintain little structure with height. The eddy kinetic energy is baroclinic with a potential energy suppresed by the large static stability of the basic state. Eddy dissipation is noted to be significant near all boundaries.

  10. Local Dynamics of Baroclinic Waves in the Martian Atmosphere

    KAUST Repository

    Kavulich, Michael J.

    2013-11-01

    The paper investigates the processes that drive the spatiotemporal evolution of baroclinic transient waves in the Martian atmosphere by a simulation experiment with the Geophysical Fluid Dynamics Laboratory (GFDL) Mars general circulation model (GCM). The main diagnostic tool of the study is the (local) eddy kinetic energy equation. Results are shown for a prewinter season of the Northern Hemisphere, in which a deep baroclinic wave of zonal wavenumber 2 circles the planet at an eastward phase speed of about 70° Sol-1 (Sol is a Martian day). The regular structure of the wave gives the impression that the classical models of baroclinic instability, which describe the underlying process by a temporally unstable global wave (e.g., Eady model and Charney model), may have a direct relevance for the description of the Martian baroclinic waves. The results of the diagnostic calculations show, however, that while the Martian waves remain zonally global features at all times, there are large spatiotemporal changes in their amplitude. The most intense episodes of baroclinic energy conversion, which take place in the two great plain regions (Acidalia Planitia and Utopia Planitia), are strongly localized in both space and time. In addition, similar to the situation for terrestrial baroclinic waves, geopotential flux convergence plays an important role in the dynamics of the downstream-propagating unstable waves. © 2013 American Meteorological Society.

  11. Flavours of Baroclinic Instability in the Global Ocean

    Science.gov (United States)

    Keating, S. R.; Smith, K. S.

    2016-02-01

    The transfer of energy from the global ocean circulation to mesoscale eddies is primarily mediated by baroclinic instability, which releases the superabundant available potential energy stored in sloping isopycnals by basin-scale wind and buoyancy forcing. However, the details of the local shear and stratification can give rise to qualitatively distinct flavours of baroclinic instability. In particular, the presence of outcropping isopycnals (or, equivalent, a thermal wind shear at the upper surface) can have a strong impact on the necessary conditions for baroclinic instability and the resulting nonlinear cascade to submesoscales. In this article, a simple framework is described for categorizing baroclinic instability in terms of two non-dimensional parameters, the Charney-Green number and the Phillips supercriticality. We analyze the influence of a non-zonal mean flow on growth rates and the baroclinic conversion of available potential energy to eddy kinetic energy. Finally, hydrographic profiles are used to form a global atlas of baroclinic instability in the ocean, and regional patterns are discussed.

  12. Nonlinear Evolution of a Baroclinic Wave and Imbalanced Dissipation

    CERN Document Server

    Nadiga, Balasubramanya T

    2015-01-01

    We consider the nonlinear evolution of an unstable baroclinic wave in a regime of rotating stratified flow that is of relevance to interior circulation in the oceans and in the atmosphere---a regime characterized by small large-scale Rossby and Froude numbers, a small vertical to horizontal aspect ratio, and no bounding horizontal surfaces. Using high-resolution simulations of the non-hydrostatic Boussinesq equations and companion integrations of the balanced quasi-geostrophic equations, we present evidence for a local route to dissipation of balanced energy directly through interior turbulent cascades. Analysis of simulations presented in this study suggest that a developing baroclinic instability can lead to secondary instabilities that can cascade a small fraction of the energy forward to unbalanced scales. Mesoscale shear and strain resulting from the hydrostatic geostrophic baroclinic instability drive frontogenesis. The fronts in turn support ageostrophic secondary circulation and instabilities. These t...

  13. Characteristics of gravity waves generated in a baroclinic instability simulation

    Directory of Open Access Journals (Sweden)

    Y.-H. Kim

    2015-11-01

    Full Text Available An idealized baroclinic instability case is simulated using a ~ 10 km resolution global model to investigate the characteristics of gravity waves (GWs generated in the baroclinic life cycle. Three groups of GWs (W1–W3 appear around the high-latitude surface trough at the mature stage of the baroclinic wave. They have horizontal and vertical wavelengths of 40–400 and 2.9–9.8 km, respectively, in the upper troposphere. The two-dimensional phase-velocity spectrum of the waves is arc-shaped with a peak at 17 m s−1 eastward, which is difficult for the waves to propagate upward through the tropospheric westerly jet. At the breaking stage of the baroclinic wave, a midlatitude surface low is isolated from the higher-latitude trough, and two groups of quasi-stationary GWs (W4 and W5 appear near the surface low. These waves have horizontal and vertical wavelengths of 60–400 and 4.9–14 km, respectively, and are able to propagate vertically for long distances. The generation mechanism of the simulated GWs is discussed.

  14. The subcritical baroclinic instability in local accretion disc models

    CERN Document Server

    Lesur, G

    2009-01-01

    (abridged) Aims: We present new results exhibiting a subcritical baroclinic instability (SBI) in local shearing box models. We describe the 2D and 3D behaviour of this instability using numerical simulations and we present a simple analytical model describing the underlying physical process. Results: A subcritical baroclinic instability is observed in flows stable for the Solberg-Hoiland criterion using local simulations. This instability is found to be a nonlinear (or subcritical) instability, which cannot be described by ordinary linear approaches. It requires a radial entropy gradient weakly unstable for the Schwartzchild criterion and a strong thermal diffusivity (or equivalently a short cooling time). In compressible simulations, the instability produces density waves which transport angular momentum outward with typically alpha<3e-3, the exact value depending on the background temperature profile. Finally, the instability survives in 3D, vortex cores becoming turbulent due to parametric instabilities...

  15. The Nonlinear Dynamics of Time Dependent Subcritical Baroclinic Currents

    Science.gov (United States)

    Pedlosky, J.; Flierl, G. R.

    2006-12-01

    The nonlinear dynamics of baroclinically unstable waves in a time dependent zonal shear flow is considered in the framework of the two-layer Phillips model on the beta plane. In most cases considered in this study the amplitude of the shear is well below the critical value of the steady shear version of the model. Nevertheless, the time dependent problem in which the shear oscillates periodically is unstable, and the unstable waves grow to substantial amplitudes, in some cases with strongly nonlinear and turbulent characteristics. For very small values of the shear amplitude in the presence of dissipation an analytical, asymptotic theory predicts a self-sustained wave whose amplitude undergoes a nonlinear oscillation whose period is amplitude dependent. There is a sensitive amplitude dependence of the wave on the frequency of the oscillating shear when the shear amplitude is small. This behavior is also found in a truncated model of the dynamics, and that model is used to examine larger shear amplitudes. When there is a mean value of the shear in addition to the oscillating component, but such that the total shear is still subcritical, the resulting nonlinear states exhibit a rectified horizontal buoyancy flux with a nonzero time average as a result of the instability of the oscillating shear. For higher, still subcritical, values of the shear we have detected a symmetry breaking in which a second cross-stream mode is generated through an instability of the unstable wave although this second mode would by itself be stable on the basic time dependent current. For shear values that are substantially subcritical but of order of the critical shear, calculations with a full quasi-geostrophic numerical model reveal a turbulent flow generated by the instability. If the beta effect is disregarded the inviscid, linear problem is formally stable. However, our calculations show that a small degree of nonlinearity is enough to destabilize the flow leading to large amplitude

  16. Ensemble Forecasting of Tropical Cyclone Motion Using a Baroclinic Model

    Institute of Scientific and Technical Information of China (English)

    Xiaqiong ZHOU; Johnny C.L.CHEN

    2006-01-01

    The purpose of this study is to investigate the effectiveness of two different ensemble forecasting (EF) techniques-the lagged-averaged forecast (LAF) and the breeding of growing modes (BGM). In the BGM experiments, the vortex and the environment are perturbed separately (named BGMV and BGME).Tropical cyclone (TC) motions in two difficult situations are studied: a large vortex interacting with its environment, and an apparent binary interaction. The former is Typhoon Yancy and the latter involves Typhoon Ed and super Typhoon Flo, all occurring during the Tropical Cyclone Motion Experiment TCM-90. The model used is the baroclinic model of the University of New South Wales. The lateral boundary tendencies are computed from atmospheric analysis data. Only the relative skill of the ensemble forecast mean over the control run is used to evaluate the effectiveness of the EF methods, although the EF technique is also used to quantify forecast uncertainty in some studies. In the case of Yancy, the ensemble mean forecasts of each of the three methodologies are better than that of the control, with LAF being the best. The mean track of the LAF is close to the best track, and it predicts landfall over Taiwan. The improvements in LAF and the full BGM where both the environment and vortex are perturbed suggest the importance of combining the perturbation of the vortex and environment when the interaction between the two is appreciable. In the binary interaction case of Ed and Flo, the forecasts of Ed appear to be insensitive to perturbations of the environment and/or the vortex, which apparently results from erroneous forecasts by the model of the interaction between the subtropical ridge and Ed, as well as from the interaction between the two typhoons, thus reducing the effectiveness of the EF technique. This conclusion is reached through sensitivity experiments on the domain of the model and by adding or eliminating certain features in the model atmosphere. Nevertheless, the

  17. The Saturnian ribbon feature: A baroclinically unstable model

    Science.gov (United States)

    Godfrey, D.

    1986-01-01

    Using measurements made by the Voyager spacecraft, an oscillatory feature in the northern midlatitudes of Saturn is examined. Measurements made by the imaging and infrared instruments are used to estimate its horizontal wavelength and vertical extent. Some of these characteristics suggest that the feature could be due to baroclinic instability. A numerical model is described of such an instability with parameters based upon the Voyager observations, and using the lower boundary condition developed by Gierasch et al for the Jovian planets.

  18. A note on boundary-layer friction in baroclinic cyclones

    CERN Document Server

    Boutle, I A; Belcher, S E; Plant, R S

    2008-01-01

    The interaction between extratropical cyclones and the underlying boundary layer has been a topic of recent discussion in papers by Adamson et. al. (2006) and Beare (2007). Their results emphasise different mechanisms through which the boundary layer dynamics may modify the growth of a baroclinic cyclone. By using different sea-surface temperature distributions and comparing the low-level winds, the differences are exposed and both of the proposed mechanisms appear to be acting within a single simulation.

  19. Fifty years of numerical modeling of baroclinic ocean

    Science.gov (United States)

    Sarkisyan, A. S.

    2012-02-01

    This paper presents a brief critical analysis of the main historical stages of numerical modeling for the last fifty years. It was a half a century ago that the numerical simulation of an actual baroclinic ocean was initiated by the author and his students [1, 2]. In meteorology, studies on the numerical modeling of a baroclinic atmosphere existed much earlier [21, 22]. Despite this, a similar move in oceanography was met with strong resistance. At that time, there were many studies on the calculation of the total mass transport. The founders of this field, V.B. Shtokman, H. Sverdrup, and W. Munk, were mistaken in believing that they addressed baroclinic models of the ocean. The author preferred works by V. Ekman [12] and I. Sandström and B. Helland-Hansen [19]. A generalization of recent studies made it possible to come to some conclusions on the need to use the level of the free oceanic surface as a basis rather than the function of total mass transport, on the role of the baroclinic β effect (BARBE), on the joint effect of baroclinicity and bottom relief (JEBAR), etc. The author conditionally divides these fifty years into the following three stages. (1) The first stage was 1961-1969, when the author and his students performed almost exclusively diagnostic and adaptation calculations of climatic characteristics. (2) The second stage began with papers by K. Bryan [23] and his students. This is an important and promising stage involving mainly prognostic studies and four-dimensional analysis. The major advances in modeling at this stage (the Gulf Stream separation point [61], the Kuroshio seasonal evolution [63], the formation of the cold intermediate layer in the Black Sea [80], the subsurface countercurrent in the Caspian Sea [25], the realistic four-dimensional analysis of the Kara Sea [60], etc.) were due to high-resolution and/or data assimilation with an adequate period of integration. (3) The third stage began with the activities of international

  20. Boundary-Layer Development and Low-level Baroclinicity during High-Latitude Cold-Air Outbreaks: A Simple Model

    Science.gov (United States)

    Chechin, Dmitry G.; Lüpkes, Christof

    2017-01-01

    A new quasi-analytical mixed-layer model is formulated describing the evolution of the convective atmospheric boundary layer (ABL) during cold-air outbreaks (CAO) over polar oceans downstream of the marginal sea-ice zones. The new model is superior to previous ones since it predicts not only temperature and mixed-layer height but also the height-averaged horizontal wind components. Results of the mixed-layer model are compared with dropsonde and aircraft observations carried out during several CAOs over the Fram Strait and also with results of a 3D non-hydrostatic (NH3D) model. It is shown that the mixed-layer model reproduces well the observed ABL height, temperature, low-level baroclinicity and its influence on the ABL wind speed. The mixed-layer model underestimates the observed ABL temperature only by about 10 %, most likely due to the neglect of condensation and subsidence. The comparison of the mixed-layer and NH3D model results shows good agreement with respect to wind speed including the formation of wind-speed maxima close to the ice edge. It is concluded that baroclinicity within the ABL governs the structure of the wind field while the baroclinicity above the ABL is important in reproducing the wind speed. It is shown that the baroclinicity in the ABL is strongest close to the ice edge and slowly decays further downwind. Analytical solutions demonstrate that the e-folding distance of this decay is the same as for the decay of the difference between the surface temperature of open water and of the mixed-layer temperature. This distance characterizing cold-air mass transformation ranges from 450 to 850 km for high-latitude CAOs.

  1. Boundary-Layer Development and Low-level Baroclinicity during High-Latitude Cold-Air Outbreaks: A Simple Model

    Science.gov (United States)

    Chechin, Dmitry G.; Lüpkes, Christof

    2016-08-01

    A new quasi-analytical mixed-layer model is formulated describing the evolution of the convective atmospheric boundary layer (ABL) during cold-air outbreaks (CAO) over polar oceans downstream of the marginal sea-ice zones. The new model is superior to previous ones since it predicts not only temperature and mixed-layer height but also the height-averaged horizontal wind components. Results of the mixed-layer model are compared with dropsonde and aircraft observations carried out during several CAOs over the Fram Strait and also with results of a 3D non-hydrostatic (NH3D) model. It is shown that the mixed-layer model reproduces well the observed ABL height, temperature, low-level baroclinicity and its influence on the ABL wind speed. The mixed-layer model underestimates the observed ABL temperature only by about 10 %, most likely due to the neglect of condensation and subsidence. The comparison of the mixed-layer and NH3D model results shows good agreement with respect to wind speed including the formation of wind-speed maxima close to the ice edge. It is concluded that baroclinicity within the ABL governs the structure of the wind field while the baroclinicity above the ABL is important in reproducing the wind speed. It is shown that the baroclinicity in the ABL is strongest close to the ice edge and slowly decays further downwind. Analytical solutions demonstrate that the e -folding distance of this decay is the same as for the decay of the difference between the surface temperature of open water and of the mixed-layer temperature. This distance characterizing cold-air mass transformation ranges from 450 to 850 km for high-latitude CAOs.

  2. Monitoring and assessment of soil erosion at micro-scale and macro-scale in forests affected by fire damage in northern Iran.

    Science.gov (United States)

    Akbarzadeh, Ali; Ghorbani-Dashtaki, Shoja; Naderi-Khorasgani, Mehdi; Kerry, Ruth; Taghizadeh-Mehrjardi, Ruhollah

    2016-12-01

    Understanding the occurrence of erosion processes at large scales is very difficult without studying them at small scales. In this study, soil erosion parameters were investigated at micro-scale and macro-scale in forests in northern Iran. Surface erosion and some vegetation attributes were measured at the watershed scale in 30 parcels of land which were separated into 15 fire-affected (burned) forests and 15 original (unburned) forests adjacent to the burned sites. The soil erodibility factor and splash erosion were also determined at the micro-plot scale within each burned and unburned site. Furthermore, soil sampling and infiltration studies were carried out at 80 other sites, as well as the 30 burned and unburned sites, (a total of 110 points) to create a map of the soil erodibility factor at the regional scale. Maps of topography, rainfall, and cover-management were also determined for the study area. The maps of erosion risk and erosion risk potential were finally prepared for the study area using the Revised Universal Soil Loss Equation (RUSLE) procedure. Results indicated that destruction of the protective cover of forested areas by fire had significant effects on splash erosion and the soil erodibility factor at the micro-plot scale and also on surface erosion, erosion risk, and erosion risk potential at the watershed scale. Moreover, the results showed that correlation coefficients between different variables at the micro-plot and watershed scales were positive and significant. Finally, assessment and monitoring of the erosion maps at the regional scale showed that the central and western parts of the study area were more susceptible to erosion compared with the western regions due to more intense crop-management, greater soil erodibility, and more rainfall. The relationships between erosion parameters and the most important vegetation attributes were also used to provide models with equations that were specific to the study region. The results of this

  3. Classroom Demonstrations Of Atmosphere-ocean Dynamics: Baroclinic Instability

    Science.gov (United States)

    Aurnou, Jonathan; Nadiga, B. T.

    2008-09-01

    Here we will present simple hands-on experimental demonstrations that show how baroclinic instabilities develop in rotating fluid dynamical systems. Such instabilities are found in the Earth's oceans and atmosphere as well as in the atmospheres and oceans of planetary bodies throughout the solar system and beyond. Our inexpensive experimental apparatus consists of a vinyl-record player, a wide shallow pan, and a weighted, dyed block of ice. Most directly, these demonstrations can be used to explain winter-time atmospheric weather patterns observed in Earth's mid-latitudes.

  4. Baroclinic instability in the two-layer model. Interpretations

    Energy Technology Data Exchange (ETDEWEB)

    Egger, Joseph [Meteorological Inst., Univ. of Munich (Germany)

    2009-10-15

    Two new interpretations of the wellknown instability criterion of the two-layer model of baroclinic instability are given whereby also a slight generalization of this model is introduced by admitting an interface on top with a reduced gravity g. It is found that instability sets in when the horizontal potential temperature advection by the barotropic mode becomes more important than the vertical temperature advection due to this mode. The second interpretation is based on potential vorticity (PV) thinking. Instability implies a dominance of the vertical PV coupling coefficient compared to horizontal mean state PV advection generated at the same level. The interface damps with decreasing g. (orig.)

  5. Eigenvalues of a baroclinic stability problem with Ekman damping

    Science.gov (United States)

    Antar, B. N.; Fowlis, W. W.

    1980-01-01

    An analytical solution is presented for the baroclinic stability problem of a Boussinesq fluid in a beta-plane channel with Ekman suction boundary conditions. All of the modes, stable and unstable, belonging to this problem are identified. It is found that an unstable mode exists for only a certain range of values of the Burger number. The value of the Burger number at the upper limit of this range increases as the Ekman number decreases. Beyond this upper limit only a damped mode exists. It is also found that this transition in parameter space from the unstable to the stable mode occurs in a discontinuous manner.

  6. An Assessment of macro-scale in situ Raman and ultraviolet-induced fluorescence spectroscopy for rapid characterization of frozen peat and ground ice

    Science.gov (United States)

    Laing, Janelle R.; Robichaud, Hailey C.; Cloutis, Edward A.

    2016-04-01

    The search for life on other planets is an active area of research. Many of the likeliest planetary bodies, such as Europa, Enceladus, and Mars are characterized by cold surface environments and ice-rich terrains. Both Raman and ultraviolet-induced fluorescence (UIF) spectroscopies have been proposed as promising tools for the detection of various kinds of bioindicators in these environments. We examined whether macro-scale Raman and UIF spectroscopy could be applied to the analysis of unprocessed terrestrial frozen peat and clear ground ice samples for detection of bioindicators. It was found that this approach did not provide unambiguous detection of bioindicators, likely for a number of reasons, particularly due to strong broadband induced fluorescence. Other contributing factors may include degradation of organic matter in frozen peat to the point that compound-specific emitted fluorescence or Raman peaks were not resolvable. Our study does not downgrade the utility of either UIF or Raman spectroscopy for astrobiological investigations (which has been demonstrated in previous studies), but does suggest that the choice of instrumentation, operational conditions and sample preparation are important factors in ensuring the success of these techniques.

  7. Baroclinic Vorticity Production in Protoplanetary Disks; Part II: Vortex Growth and Longevity

    CERN Document Server

    Petersen, M R; Julien, K; Petersen, Mark R.; Stewart, Glen R.; Julien, Keith

    2006-01-01

    The factors affecting vortex growth in convectively stable protoplanetary disks are explored using numerical simulations of a two-dimensional anelastic-gas model which includes baroclinic vorticity production and radiative cooling. The baroclinic feedback, where anomalous temperature gradients produce vorticity through the baroclinic term and vortices then reinforce these temperature gradients, is found to be an important process in the rate of growth of vortices in the disk. Factors which strengthen the baroclinic feedback include fast radiative cooling, high thermal diffusion, and large radial temperature gradients in the background temperature. When the baroclinic feedback is sufficiently strong, anticyclonic vortices form from initial random perturbations and maintain their strength for the duration of the simulation, for over 600 orbital periods. Based on both simulations and a simple vortex model, we find that the local angular momentum transport due to a single vortex may be inward or outward, dependin...

  8. Laboratory experiments in a baroclinic annulus with heating and cooling on the horizontal boundaries

    Science.gov (United States)

    Miller, T. L.; Fowlis, W. W.

    1986-01-01

    Experiments have been performed in a cylindrical annulus with horizontal temperature gradients imposed upon the horizontal boundaries and in which the vertical depth was smaller than the width of the annulus. Qualitative observations were made by the use of small, suspended, reflective flakes in the liquid (water). Four basic regimes of flow were observed: (1) axisymmetric flow, (2) deep cellular convection, (3) boundary layer convective rolls, and (4) baroclinic waves. In some cases there was a mix of baroclinic and convective instabilities present. As a 'mean' interior Richardson number was decreased from a value greater than unity to one less than zero, axisymmetric baroclinic instability of the Solberg type was never observed. Rather, the transition was from non-axisymmetric baroclinic waves, to a mix of baroclinic and convective instability, to irregular cellular convection.

  9. Macro Scale Hydrologic Modeling for Water Management: Re-construction of Large Reservoir Storage Time Series in the Continental U.S

    Science.gov (United States)

    Zhou, T.; Nijssen, B.; Haddeland, I.; Lettenmaier, D. P.

    2013-12-01

    Water management activities such as irrigation water withdrawal, hydropower generation, and flood control, substantially change water fluxes at the land surface and redistribute the storage of surface water in space and time. Although most developed countries have sophisticated observing systems for most variables in the surface water cycle, long-term and consistent records that focus on water management and human impacts on the water cycle are less available. We describe a continental-scale model of reservoir storage, which is combined with a soil moisture deficit-based irrigation scheme within the Variable Infiltration Capacity (VIC) macro scale hydrology model to simulate the effects of water management in the major river basins of the continental U.S. The model is forced with merged NCEP/NCAR and satellite meteorological data at a spatial resolution of 0.5 degrees latitude-longitude, for the period 1948 to 2008. A total of 120 of the largest reservoirs in the U.S. with a storage capacity greater than 1,000,000 acre feet are simulated. Two key variables, time series of monthly irrigation water consumption and monthly reservoir storage, which reflect the water management impacts, are extracted from the model results. The simulation results indicate that the model is able to estimate irrigation water demands successfully in comparison with observations and other inferences, and to accurately re-construct reservoir storage time series. We also discuss early results from global simulations, which allow us to assess human impacts on the global land surface water cycle in data-sparse regions.

  10. A Vertical Grid Module for Baroclinic Models of the Atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Drake, John B [ORNL

    2008-04-01

    The vertical grid of an atmospheric model assigns dynamic and thermo- dynamic variables to grid locations. The vertical coordinate is typically not height but one of a class of meteorological variables that vary with atmo- spheric conditions. The grid system is chosen to further numerical approx- imations of the boundary conditions so that the system is terrain following at the surface. Lagrangian vertical coordinates are useful in reducing the numerical errors from advection processes. That the choices will effect the numercial properties and accuracy is explored in this report. A MATLAB class for Lorentz vertical grids is described and applied to the vertical struc- ture equation and baroclinic atmospheric circulation. A generalized meteo- rolgoical coordinate system is developed which can support σ, isentropic θ vertical coordinate, or Lagrangian vertical coordinates. The vertical atmo- spheric column is a MATLAB class that includes the kinematic and ther- modynamic variables along with methods for computing geopoentials and terms relevant to a 3D baroclinc atmospheric model.

  11. Vertical propagation of baroclinic Kelvin waves along the west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Nethery, D.; Shankar, D.

    A linear, continuously stratified ocean model is used to investigate vertical propagation of remotely forced, baroclinic Kelvin waves along the Indian west coast. The extent of vertical propagation over the length of the coast is found...

  12. Delayed baroclinic response of the Antarctic circumpolar current to surface wind stress

    Institute of Scientific and Technical Information of China (English)

    YANG XiaoYi; HUANG RuiXin; WANG Jia; WANG DongXiao

    2008-01-01

    The Antarctic Circumpolar Current (ACC) responds to the surface windstress via two processes,i.e.,the instant barotropic process and the delayed baroclinic process. This study focuses on the baroclinic instability mechanism in ACC,which was less reported in the literatures. Results show that the strengthening of surface zonal windstress causes the enhanced tilting of the isopycnal surface,leading to more intense baroclinic instability. Simultaneously,the mesoscale eddies resulting from the baroclinic instability facilitate the transformation of mean potential energy to eddy energy,which causes the remarkable decrease of the ACC volume transport with the 2-year lag time. This delayed negative correlation between the ACC transport and the zonal windstress may account for the steadiness of the ACC transport during last two decades.

  13. Evaluation of Baroclinic ADCIRC Using a Process-Oriented Test Along a Slope

    Science.gov (United States)

    2013-05-30

    oriented tests, such as those suggested by Haidvogel and Beckmann (1999), are often utilized in the validation of baroclinic processes in shallow...front along a slope, the "gravity adjustment" test case suggested by Haidvogel and Beckmann (1999). In this analysis, water of different densities is...suggested by Haidvogel and Beckmann (1999), are often utilized in the validation of baroclinic processes in shallow water models. In a previous analysis

  14. Generation of deep eddies by a turning baroclinic jet

    Science.gov (United States)

    Sutyrin, Georgi

    2015-07-01

    The North Atlantic Current (NAC) travels northward east of the Grand Banks until approximately 50°N where it makes a sharp turn to the east. Previous analysis of sea level variability in this region, known as the Northwest Corner, showed large-amplitude meandering and a quasi-regular production of anticyclonic eddies playing an important role in the air-sea heat exchange. Here we investigate key physical mechanisms of meandering of an idealized upper ocean turning jet using a two-layer model. The existing reduced-gravity thin jet theory is modified to take into account the crossjet velocity in the lower layer induced by the jet meanders. Such coupled system is capable to describe realistically baroclinic instability and to reduce the two-dimensional initial value problem to a rather simple one-dimensional formulation. Its linearized version is solved here to describe the fluid motion in both layers in terms of jet curvature. It is found that transient meander growth is enhanced in the vicinity of turning point owing to vertical coupling with deep eddies generated due to stretching in water column beneath growing meanders. Scaling for initial growth of deep cyclone-anticyclone pair is suggested based on a generalized thin jet theory. Patterns of further nonlinear evolution resembling observational data are described.

  15. BAROCLINIC INSTABILITY IN THE SOLAR TACHOCLINE. II. THE EADY PROBLEM

    Energy Technology Data Exchange (ETDEWEB)

    Gilman, Peter A., E-mail: gilman@ucar.edu [High Altitude Observatory, National Center for Atmospheric Research, 3080 Center Green, Boulder, CO 80307-3000 (United States)

    2016-02-20

    We solve the nongeostrophic baroclinic instability problem for the tachocline for a continuous model with a constant vertical rotation gradient (the Eady problem), using power series generated by the Frobenius method. The results confirm and greatly extend those from a previous two-layer model. For effective gravity G independent of height, growth rates and ranges of unstable longitudinal wavenumbers m and latitudes increase with decreasing G. As with the two-layer model, the overshoot tachocline is much more unstable than the radiative tachocline. The e-folding growth times range from as short as 10 days to as long as several years, depending on latitude, G, and wavenumber. For a more realistic effective gravity that decreases linearly from the radiative interior to near zero at the top of the tachocline, we find that only m = 1, 2 modes are unstable, with growth rates somewhat larger than for constant G, with the same value as at the bottom of the tachocline. All results are the same whether we assume that the vertical velocity or the perturbation pressure is zero at the top of the layer; this is a direct consquence of not employing the geostrophic assumption for perturbations. We explain most of the properties of the instability in terms of the Rossby deformation radius. We discuss further improvements in the realism of the model, particularly adding toroidal fields that vary in height, and including latitudinal gradients of both rotation and toroidal fields.

  16. Three dimensional chaotic advection by mixed layer baroclinic instabilities

    CERN Document Server

    Mukiibi, Daniel; Serra, Nuno

    2015-01-01

    Three dimensional (3D) Finite Time Lyapunov Exponents (FTLEs) are computed from numerical simulations of a freely evolving mixed layer (ML) front in a zonal channel undergoing baroclinic instability. The 3D FTLEs show a complex structure, with features that are less defined than the two-dimensional (2D) FTLEs, suggesting that stirring is not confined to the edges of vortices and along filaments and posing significant consequences on mixing. The magnitude of the FTLEs is observed to be strongly determined by the vertical shear. A scaling law relating the local FTLEs and the nonlocal density contrast used to initialize the ML front is derived assuming thermal wind balance. The scaling law only converges to the values found from the simulations within the pycnocline, while it displays differences within the ML, where the instabilities show a large ageostrophic component. The probability distribution functions of 2D and 3D FTLEs are found to be non Gaussian at all depths. In the ML, the FTLEs wavenumber spectra d...

  17. Energy distributions of the large-scale horizontal currents caused by wind in the baroclinic ocean

    Institute of Scientific and Technical Information of China (English)

    ZHOU; Lei; TIAN; Jiwei; WANG; Dongxiao

    2005-01-01

    Ocean current data for nearly 3 months in the South China Sea (SCS), combined with the NCEP/NCAR reanalysis wind data, are analyzed. The results indicate that the wind energy enters the upper mixed layer in a wide continuous frequency band. In addition, the interaction between the low-frequency wind anomaly and the low-frequency current anomaly is the most ‘effective’ way for the energy input from the wind to the upper ocean. However, only the inertial and the near inertial energy propagate downwards through the upper mixed layer. The downward-propagating energy is distributed into the barotropic currents, the baroclinic currents and each mode of the baroclinic currents following the normal distributions. The energy change ratios between the barotropic motion to the baroclinic motion induced by the wind present a normal distribution of N (0.0242, 0.3947). The energy change ratios of the first 4 baroclinic modes to the whole baroclinic currents also follow the normal distributions. The first baroclinic mode follows N (0.2628, 0.1872), the second N (0.1979, 0.1504), the third N (0.1331, 0.1633), and the fourth N (0.0650, 0.1540), respectively.

  18. Partially Melted UHP Eclogite in the Sulu Orogenic Belt, China and its rheological significance to deep continental subduction: Micro- to Macro-scale Evidence

    Science.gov (United States)

    Wang, Lu; Kusky, Timothy; Polat, Ali; Wang, Songjie; Jiang, Xingfu; Zong, Keqing; Wang, Junpeng; Deng, Hao; Fu, Jianmin

    2015-04-01

    Partially Melted UHP Eclogite in the Sulu Orogenic Belt, China and its rheological significance to deep continental subduction: Micro- to Macro-scale Evidence Numerous studies have described partial melting processes in low-high pressure meta-sedimentary rocks, some of which may generate melts that coalesce to form plutons. However, migmatized ultrahigh pressure (UHP) eclogite has never been clearly described from the microscale to macroscale, though experimental studies prove dehydration partial melting of eclogite at high pressure condition1 and low degrees of partially melted eclogite have been reported from the Qaidam UHP orogenic belt in NW China2,3 or inferred from multiphase solid (MS) inclusions within eclogite4 in the Sulu UHP belt. We present field-based documentation of decompression partial melting of UHP eclogite from Yangkou and General's Hill, Sulu Orogen. Migmatized eclogite shows successive stages of anatexis, initially starting from intragranular and grain boundary melt droplets, which grow into a 3D interconnected intergranular network, then segregate and accumulate in pressure shadow areas, and finally merge to form melt channels and dikes that transport melts to upper lithospheric levels. In-situ phengite breakdown-induced partial melting is directly identified by MS inclusions of Kfs+ barium-bearing Kfs + Pl in garnet, connected by 4-10 μm wide veinlets consisting of Bt + Kfs + Pl next to the phengite. Intergranular veinlets of plagioclase + K-feldspar first form isolated beads of melt along grain boundaries and triple junctions of quartz, and with higher degrees of melting, eventually form interconnected 3D networks along grain boundaries in the leucosome, allowing melt to escape from the intergranular realm and collect in low-stress areas. U-Pb (zircon) dating and petrological analyses on residue and leucocratic rocks shows that partial melting occurred at 228-219 Ma, shortly after peak UHP metamorphism (~230 Ma), and at depths of 30-90 km

  19. Empirical singular vectors of baroclinic flows deduced from experimental data of a differentially heated rotating annulus

    Directory of Open Access Journals (Sweden)

    Michael Hoff

    2015-01-01

    Full Text Available Instability is related to exponentially growing eigenmodes. Interestingly, when finite time intervals are considered, growth rates of certain initial perturbations can exceed the growth rates of the most unstable modes. Moreover, even when all modes are damped, such particular initial perturbations can still grow during finite time intervals. The perturbations with the largest growth rates are called singular vectors (SVs or optimal perturbations. They not only play an important role in atmospheric ensemble predictions, but also for the theory of instability and turbulence. Starting point for a classical SV-analysis is a linear dynamical system with a known system matrix. In contrast to this traditional approach, measured data are used here to estimate the linear propagator. For this estimation, a method is applied that uses the covariances of the measured time series to find the principal oscillation patterns (POPs that are the empirically estimated linear eigenmodes of the system. By using the singular value decomposition (SVD, we can estimate the modes of maximal growth of the propagator which are thus the empirically estimated SVs. These modes can be understood as a superposition of POPs that form a complete but in general non-orthogonal basis. The data used, originate from a differentially heated rotating annulus laboratory experiment. This experiment is an analogue of the earth's atmosphere and is used to study the development of baroclinic waves in a well controlled and reproducible way without the need of numerical approximations. Baroclinic waves form the background for many studies on SV growth and it is thus straight forward to apply the technique of empirical SV estimation to these laboratory data. To test the method of SV estimation, we use a quasi-geostrophic barotropic model and compare the known SVs from that model with SVs estimated from a surrogate data set that was generated with the help of the exact model propagator and some

  20. Influence of pH and Chloride Concentration on the Corrosion Behavior of Unalloyed Copper in NaCl Solution: A Comparative Study Between the Micro and Macro Scales

    Directory of Open Access Journals (Sweden)

    Annemie Adriaens

    2012-11-01

    Full Text Available The effects of pH and chloride concentration on the electrochemical corrosion of copper in aqueous sodium chloride (NaCl media were studied at the micro scale using a microcapillary droplet cell and at the macro scale using a conventional large scale cell. Using an experimental design strategy, electrochemical response surface models of copper versus pH and NaCl concentration were constructed with the minimum number of experiments required. Results show that the electrochemical behavior of copper under corrosive media shows significant differences between the micro and macro scale experiments. At the micro scale, the pit initiation of copper occurs at more negative potentials for high NaCl concentrations and alkaline pH values. Also, the micro scale potentiostatic measurements indicate higher stabilised passive currents at high NaCl concentrations and low (acidic pH values. At the macro scale, the pH is shown to have a greater influence on the corrosion potential. The chloride concentration is the most significant factor in the passive current case while at the micro scale the effect of these two factors on the passive current was found to be the same. The surface morphology of the formed patina on the corroded copper in both micro and macro systems reveal a more significant role of the chloride concentration on the structure and the grain size of the patinas. Finally, micro and macro electrochemical impedance spectroscopy of copper at various NaCl concentrations and pH values demonstrates a different behavior of copper after several potentiodynamic polarization cycles.

  1. Lyapunov, Floquet, and singular vectors for baroclinic waves

    Directory of Open Access Journals (Sweden)

    R. M. Samelson

    2001-01-01

    Full Text Available The dynamics of the growth of linear disturbances to a chaotic basic state is analyzed in an asymptotic model of weakly nonlinear, baroclinic wave-mean interaction. In this model, an ordinary differential equation for the wave amplitude is coupled to a partial differential equation for the zonal flow correction. The leading Lyapunov vector is nearly parallel to the leading Floquet vector f1 of the lowest-order unstable periodic orbit over most of the attractor. Departures of the Lyapunov vector from this orientation are primarily rotations of the vector in an approximate tangent plane to the large-scale attractor structure. Exponential growth and decay rates of the Lyapunov vector during individual Poincaré section returns are an order of magnitude larger than the Lyapunov exponent l ≈ 0.016. Relatively large deviations of the Lyapunov vector from parallel to f1 are generally associated with relatively large transient decays. The transient growth and decay of the Lyapunov vector is well described by the transient growth and decay of the leading Floquet vectors of the set of unstable periodic orbits associated with the attractor. Each of these vectors is also nearly parallel to f1. The dynamical splitting of the complete sets of Floquet vectors for the higher-order cycles follows the previous results on the lowest-order cycle, with the vectors divided into wave-dynamical and decaying zonal flow modes. Singular vectors and singular values also generally follow this split. The primary difference between the leading Lyapunov and singular vectors is the contribution of decaying, inviscidly-damped wave-dynamical structures to the singular vectors.

  2. Observation of baroclinic eddies southeast of Okinawa Island

    Institute of Scientific and Technical Information of China (English)

    PARK; Jae-Hun

    2008-01-01

    In the region southeast of Okinawa, during May to July 2001, a cyclonic and an anticyclonic eddy were observed from combined measurements of hydrocasts, an upward-looking moored acoustic Doppler current profiler (MADCP), pressure-recording inverted echo sounders (PIESs), satellite altimetry, and a coastal tide gauge. The hydrographic data showed that the lowest/highest temperature (T) and salinity (S) anomalies from a 13-year mean for the same season were respectively -3.0/+2.5℃ and -0.20/+0.15 psu at 380/500 dbar for the cyclonic/anticyclonic eddies. From the PIES data, using a gravest empirical mode method, we estimated time-varying surface dynamic height (D) anomaly referred to 2000 dbar changing from -20 to 30 cm, and time-varying T and S anomalies at 500 dbar ranging through about ±2 ℃ and ±0.2 psu, respectively. The passage of the eddies caused variations of both satellite-measured sea surface height anomaly (SSHA) and tide-gauge-measured sea level anomaly to change from about –20 to 30 cm, consistent with the D anomaly from the PIESs. Bottom pressure sensors measured no variation related to these eddy activities, which indicated that the two eddies were dominated by baro-clinicity. Time series of SSHA map confirmed that the two eddies, originating from the North Pacific Subtropical Countercurrent region near 20°―30°N and 150°―160°E, traveled about 3000 km for about 18 months with mean westward propagation speed of about 6 cm/s, before arriving at the region southeast of Okinawa Island.

  3. Baroclinic Effects on Tidal Propagation and Estuarine Circulation: an Idealized Modeling Analysis

    Science.gov (United States)

    Cao, Z.; Olabarrieta, M.

    2016-02-01

    This study evaluates the baroclinic effects on the propagation of a semidiurnal tide and on the estuarine circulation by applying a three-dimensional Regional Ocean Modeling System (ROMS) to an idealized estuary. Different riverine flows and tidal amplitudes are considered to generate various types of estuaries (from strongly stratified to well mixed) in the estuarine parameter space, which is based on the freshwater Froude number (Fr) and mixing number (M). Two groups of scenarios, with and without density difference between riverine flow and ocean water, are carried out. Tidal wave characteristics and residual currents of each scenario are investigated. In strongly stratified estuaries, the baroclinic effects result in a typical bidirectional estuarine circulation, with the surface water flowing downstream and bottom water flowing upstream; if no density variations are considered, the residual current will flow downstream. In well mixed estuaries, surface water goes upstream due to Stokes Drift and bottom water goes downstream as a compensating flow, which can be found in both barotropic and baroclinic simulations. In partially mixed estuaries, without considering the density variations, the estuarine circulation patterns are similar to those in well mixed estuaries; the baroclinic effects will generate a triple-directional estuarine circulation, characterized by a downstream flow below the tidal wave trough and an upstream flow close to the bottom; between the wave crest and trough the residual current is directed upstream due to the Stokes Drift. Tidal amplitude is increasingly amplified from estuary mouth to head in all scenarios, and the intensity of this amplification is larger in baroclinic simulations. The strongest baroclinic effects on the tidal propagation occur in partially mixed estuaries, where the tidal amplitude can increase up to 30% due to baroclinic effects.

  4. The impact of baroclinic eddy feedback on the persistence of jet variability in the two-layer model

    OpenAIRE

    Zurita-Gotor, Pablo; Blanco-Fuentes, Javier; Gerber, E. P.

    2013-01-01

    Although it is well known that the persistence of extratropical jet shifts is enhanced by a positive eddy feedback, the dynamics of this feedback is still debated. Two types of mechanisms have been proposed: barotropic mechanisms rely on changes in upper-level propagation and baroclinic mechanisms rely on the coupling between barotropic and baroclinic flow. Recent studies have suggested that barotropic models can capture key aspects of the observed jet variability but the role of baroclinic d...

  5. On the sensitivities of idealized moist baroclinic waves to environmental temperature and moist convection

    Science.gov (United States)

    Kirshbaum, Daniel; Merlis, Timothy; Gyakum, John; McTaggart-Cowan, Ron

    2017-04-01

    The impact of cloud diabatic heating on baroclinic life cycles has been studied for decades, with the nearly universal finding that this heating enhances the system growth rate. However, few if any studies have systematically addressed the sensitivity of baroclinic waves to environmental temperature. For a given relative humidity, warmer atmospheres contain more moisture than colder atmospheres. They also are more prone to the development of deep moist convection, which is itself a major source of diabatic heating. Thus, it is reasonable to expect faster baroclinic wave growth in warmer systems. To address this question, this study performs idealized simulations of moist baroclinic waves in a periodic channel, using initial environments with identical relative humidities, dry stabilities, and dry available potential energies but varying environmental temperatures and moist instabilities. While the dry versions of these simulations exhibit virtually identical wave growth, the moist versions exhibit major differences in life cycle. Counter-intuitively, despite slightly faster initial wave growth, the warmer and moister waves ultimately develop into weaker baroclinic systems with an earlier onset of the decay phase. An energetics analysis reveals that the reduced wave amplitude in the warmer cases stems from a reduced transfer of available potential energy into eddy potential energy. This reduced energy transfer is associated with an unfavorable phasing of mid-to-upper-level thermal and vorticity anomalies, which limits the meridional heat flux.

  6. An experimental study of regime transitions in a differentially heated baroclinic annulus with flat and sloping bottom topographies

    CERN Document Server

    Vincze, Miklos; von Larcher, Thomas; Egbers, Christoph

    2013-01-01

    A series of laboratory experiments has been carried out in a thermally driven rotating annulus to study the onset of baroclinic instability, using horizontal and uniformly sloping bottom topographies. Different wave flow regimes have been identified and their phase boundaries -- expressed in terms of appropriate non-dimensional parameters -- have been compared to the recent numerical results of \\citet{thomas_slope}. In the flat bottom case, the numerically predicted alignment of the boundary between the axisymmetric and the regular wave flow regime was found to be consistent with the experimental results. However, once the sloping bottom end wall was introduced, the detected behaviour was qualitatively different from that of the simulations. This disagreement is thought to be the consequence of nonlinear wave-wave interactions that could not be resolved in the framework of the numerical study. This argument is supported by the observed development of interference vacillation in the runs with sloping bottom, a...

  7. Nonlinear features of equatorial baroclinic Rossby waves detected in Topex altimeter observations

    Directory of Open Access Journals (Sweden)

    R. E. Glazman

    1996-01-01

    Full Text Available Using a recently proposed technique for statistical analysis of non-gridded satellite altimeter data, regime of long equatorially-trapped baroclinic Rossby waves is studied. One-dimensional spatial and spatiotemporal autocorrelation functions of sea surface height (SSH variations yield a broad spectrum of baroclinic Rossby waves and permit determination of their propagation speed. The 1-d wavenumber spectrum of zonal variations is given by a power-law k-2 on scales from about 103 km to 104 km. We demonstrate that the observed wave regime exhibits features of soliton turbulence developing in the long baroclinic Rossby waves. However, being limited to second statistical moments, the present analysis does not allow us to rule out a possibility of weak wave turbulence.

  8. Vortices in stratified protoplanetary disks : from baroclinic instability to vortex layers

    CERN Document Server

    Richard, S; Dizes, S Le

    2016-01-01

    Large scale vortices could play a key role in the evolution of protoplanetary disks, particularly in the dead-zone where no turbulence associated with magnetic field is expected. Their possible formation by the subcritical baroclinic instability is a complex issue due to the vertical structure of the disk and to the elliptical instability.} {In two-dimensional disks the baroclinic instability is studied as a function of the thermal transfer efficiency. In three-dimensional disks we explore the importance of radial and vertical stratification on the processes of vortex formation and amplification.} {Numerical simulations are performed using a fully compressible hydrodynamical code based on a second order finite volume method. We assume a perfect gas law in inviscid disk models in which heat transfer is due to either relaxation or diffusion.} {In 2D, the baroclinic instability with thermal relaxation leads to the formation of large-scale vortices, which are unstable with respect to the elliptic instability. In ...

  9. Zonal jets in equilibrating baroclinic instability on the polar beta-plane: experiments with altimetry

    CERN Document Server

    Matulka, A M

    2015-01-01

    Results from the laboratory experiments on the evolution of baroclinically unstable flows generated in a rotating tank with topographic beta-effect are presented. We study zonal jets of alternating direction which occur in these flows. The primary system we model includes lighter fluid in the South and heavier fluid in the North with resulting slow meridional circulation and fast mean zonal motion. In a two-layer system the velocity shear between the layers results in baroclinic instability which equilibrates with time and, due to interaction with beta-effect generates zonal jets. This system is archetypal for various geophysical systems including the general circulation and jet streams in the Earths atmosphere, the Antarctic Circumpolar Current or the areas in the vicinity of western boundary currents where baroclinic instability and multiple zonal jets are observed. The gradient of the surface elevation and the thickness of the upper layer are measured in the experiments using the Altimetric Imaging Velocim...

  10. Delayed baroclinic response of the Antarctic circum-polar current to surface wind stress

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The Antarctic Circumpolar Current (ACC) responds to the surface windstress via two processes, i.e., the instant barotropic process and the delayed baroclinic process. This study focuses on the baroclinic instability mechanism in ACC, which was less reported in the literatures. Results show that the strengthening of surface zonal windstress causes the enhanced tilting of the isopycnal surface, leading to more intense baroclinic instability. Simultaneously, the mesoscale eddies resulting from the baro- clinic instability facilitate the transformation of mean potential energy to eddy energy, which causes the remarkable decrease of the ACC volume transport with the 2-year lag time. This delayed negative cor- relation between the ACC transport and the zonal windstress may account for the steadiness of the ACC transport during last two decades.

  11. Vertical Structure of Baroclinic Currents over Northern South China Sea Continental Slope

    Institute of Scientific and Technical Information of China (English)

    邱章

    2001-01-01

    The 28.6 d time series of ADCP currents at 27 depth levels, (11,15,…,115m) which are obtained from a mooring station at the northern South China Sea continental slope, have been decomposed into barotropic and baroclinic components. The emphasis in this paper is on the analysis of the time series of baroclinic currents by means of several methods,such as the tidal harmonic analysis, the power spectra and the kinetic energy estimation.The major results are as follows: (1) In respect of the baroclinic currents, the values of several parameters first decrease and then increase with depth. These parameters include the temporal mean value of the cross-shelf component, the standard deviations, the amplitudes of K1 constituents, the mean eddy kinetic energy, as well as the significant peaks of the power spectra of the cross-shelf components. (2) The diurnal period of the baroclinic currents is dominant. The diumal tidal current rotates clockwise and the major axis of current ellipse is located along the directions of NW-SE. The vertical distribution of the phases of the diurnal constituent varies with the different water layers. Around the 67m depth level, the phase changes very much.At those layers far away from the 67m depth level, the vertical distribution of the phase is relatively stable, but with opposite phases in the upper and lower water layers. For the upper layers between the surface and 67m,the phases are around 300°; for the lower layers between 67m and 115m, the phases are around 120° .(3) The mean eddy kinetic energy of the baroclinic current is quite large, accounting for 41% of the mean kinetic energy of the measured currents. The cross-shelf component is larger than the along-shelf one. The two baroclinic current components correspond to the major and minor axes of the current ellipse of the diurnal constituent respectively. (4) The power spectra of the baroclinic currents show a singnificant period of about 24h, with 23.6h at both 19m and 99m and 24

  12. Dust-infused baroclinic cyclone storm clouds: The evidence, meteorology, and some implications

    Science.gov (United States)

    Fromm, Michael; Kablick, George; Caffrey, Peter

    2016-12-01

    Desert mineral dust is a critical yet still poorly understood component of atmospheric composition, weather, and climate. Long-range transport of dust is well known, yet uncertainty persists regarding the pathway from the desert floor to the free troposphere. Here we will show that a recurrent pathway for dust into the uppermost troposphere involves passage through an extratropical baroclinic cyclonic storm. The evidence derives from a synergistic use of satellite-based, multispectral nadir-image data and lidar. The dust-infused baroclinic storm (DIBS) exhibits peculiar cirrus cloud top reflected and emitted radiance from the UV through thermal IR, involving positive UV absorbing aerosol index, muted visible reflectivity, visible cumuliform texture, and systematically intense visible lidar backscatter on a synoptic scale. Proof that the DIBS is microphysically impacted by storm-scale dust infusion is the occurrence of anomalously large daytime 3.9-11μm brightness temperature difference indicative of small ice crystals. We present multispectral snapshots of two DIBS, over two desert source regions, in comparison with a pristine baroclinic storm cloud. Each storm snapshot is presented in the context of the baroclinic cyclone's lifetime and dust source region (the Gobi desert and the Sahara). These and other cases discussed show that the DIBS is a recurring conduit for long-range transport and a natural experiment in dust-related aerosol indirect effects.

  13. The effect of baroclinicity on the wind in the planetary boundary layer

    DEFF Research Database (Denmark)

    Floors, Rogier Ralph; Peña, Alfredo; Gryning, Sven-Erik

    2015-01-01

    using the wind lidar, was influenced by baroclinicity. For easterly winds at Høvsøre, the estimated gradient wind decreased rapidly with height, resulting in a mean low-level jet. The turning of the wind in the boundary layer, the boundary-layer height and the empirical constants in the geostrophic drag...

  14. Increase of upper troposphere/lower stratosphere wave baroclinicity during the second half of the 20th century

    Directory of Open Access Journals (Sweden)

    J. M. Castanheira

    2009-09-01

    Full Text Available A strengthening of the equatorward temperature gradient in the upper troposphere/lower stratosphere (UTLS, at subtropics and midlatitudes, is consistently reproduced in several modelling studies of the atmospheric response to the increase of greenhouse gas radiative forcing. Some of those studies suggest an increase of the baroclinicity in the UTLS region because of the enhanced meridional temperature gradient.

    This study presents observational evidence of an increase of UTLS wave baroclinicity, during the second half of the 20th century. The evidence is given by significant positive trends in the energy of baroclinic normal modes of the NCEP/NCAR reanalysis, and significant positive trends in the eddy available potential energy of the ERA-40 reanalysis as well as in the eddy available potential energy of the JRA-25 reanalysis. Significant positive trends in the frequency of double tropopause events in radiosonde data are also interpreted as a manifestation of an increase of the UTLS wave baroclinicity.

  15. Three Dimensional Baroclinic Numerical Model for Simulating Fresh and Salt Water Mixing in the Yangtze Estuary

    Institute of Scientific and Technical Information of China (English)

    郑金海; 严以新; 诸裕良

    2002-01-01

    For simulating fresh and salt water mixing in estuaries, a three dimensional nonlinear baroclinic numerical model isdeveloped, in which the gradients of horizontal pressure contain the gradient of barotropic pressure arising from the gradi-ent of tidal level and the gradient of baroclinic pressure due to the gradient of salinity. The Eulerian-Lagrangian method isemployed to descretize both the momentum equations of tidal motion and the equation of salt water diffusion so as to im-prove the computational stability and accuracy. The methods to provide the boundary conditions and the initial conditionsare proposed, and the criterion for computational stability of the salinity fields is presented. The present model is used formodeling fresh and salt water mixing in the Yangtze Estuary. Computations show that the salinity distribution has thecharacteristics of partial mixing pattern, and that the present model is suitable for simulation of fresh and salt water mixing in the Yangtze Estuary.

  16. Baroclinic instability of easterly jets with applications to the summer mesosphere

    Science.gov (United States)

    Pfister, L.

    1985-01-01

    A two-dimensional numerical analysis of baroclinic instability waves in zonally and seasonally averaged wind fields in the summer mesosphere is presented. The analysis is based on the linearized quasi-geostrophic potential vorticity equation of Simmons and Moskins (1973). Solutions are obtained for the wave structure, wave growth rates, and wave periods on the basis of idealized and realistic data, and the results are compared with one-dimensional analyses. It is shown that the wavenumbers of peak growth with periods of 1.4-3 days were consistently lower for the two-dimensional analysis than for previous one-dimensional analyses. The possibility of detecting baroclinic instability in summer winds at 80-100 km by means of nadir-sounding satellite observations is discussed.

  17. Physical modelling of baroclinic development in the lee of the Alps

    Directory of Open Access Journals (Sweden)

    E. Ferrero

    1997-06-01

    Full Text Available When baroclinic development is triggered by an obstacle, like an extended mountain range, the so-called lee, or secondary cyclogenesis can develop. The presence of the obstacle exerts a blocking effect on the lower layers of the impinging airflow, forcing them to go round its borders and reach the lee region with a delay. Blocking and delay are both responsible for the initial pressure decrease downwind of the mountain and for the subsequent proper downstream baroclinic development. According to this rather simple scheme, a cyclogenesis episode in the lee of the Alps was simulated in a hydraulic turntable. The results of these experiments showed a good agreement, both from a qualitative and quantitative point of view, with the analysis of an episode of lee cyclogenesis coupled to a cold outbreak in the Mediterranean, which actually occured in Southern Europe downstream of the Alps.

  18. The meridional variation of the eddy heat fluxes by baroclinic waves and their parameterization

    Science.gov (United States)

    Stone, P. H.

    1974-01-01

    The meridional and vertical eddy fluxes of sensible heat produced by small-amplitude growing baroclinic waves are calculated using solutions to the two-level model with horizontal shear in the mean flow. The results show that the fluxes are primarily dependent on the local baroclinicity, i.e., the local value of the isentropic slopes in the mean state. Where the slope exceeds the critical value, the transports are poleward and upward; where the slope is less than the critical value, the transports are equatorward and downward. These results are used to improve an earlier parameterization of the tropospheric eddy fluxes of sensible heat based on Eady's model. Comparisons with observations show that the improved parameterization reproduces the observed magnitude and sign of the eddy fluxes and their vertical variations and seasonal changes, but the maximum in the poleward flux is too near the equator.

  19. NUMERICAL STUDY ON THE FORMATION OF THE SOUTH CHINA SEA WARM CURRENT II. BAROCLINIC CASE

    Institute of Scientific and Technical Information of China (English)

    王凯; 方国洪; 施心慧

    2001-01-01

    In this part, Levitus' climatological temperature and salinity are incorporated in the numerical model developed in Part I. Diagnostic and prognostic experiment on the thermohaline circulation were conducted. The smooth Levitus' data do not include any information on the South China Sea Warm Current (SCSWC), so it is not in the model-produced diagnostic thermohaline circulation. Although the SCSWC does not appear in the wind-driven circulation in the barotropic case, it appears in the prognostic wind-driven circulation in the baroclinic case. This implies that the differing circulation patterns between barotropic case and baroclinic case are due to the stratification. The prognostic thermohaline circulation with wind stress and inflow/outflow transports at open boundaries are also discussed. Coupling of density and dynamic forces makes the circulation pattern more complicated. Even though the stratification is not always a direct cause of the formation of the SCSWC, it is at least an indirect cause.``

  20. Vertical propagation of baroclinic Kelvin waves along the west coast of India

    Indian Academy of Sciences (India)

    D Nethery; D Shankar

    2007-08-01

    A linear, continuously stratified ocean model is used to investigate vertical propagation of remotely forced, baroclinic Kelvin waves along the Indian west coast. The extent of vertical propagation over the length of the coast is found to be an increasing function of the forcing frequency. Simulations show that, over the length of the Indian west coast, vertical propagation is limited at annual and semi-annual periods, but significant at periods shorter than about 120 days. This has two major consequences. First, the depth of subsurface currents associated with these frequencies varies substantially along the coast. Second, baroclinic Kelvin waves generated in the Bay of Bengal at periods shorter than about 120 days have negligible influence on surface currents along the north Indian west coast.

  1. Covariant Lyapunov Vectors of a Quasi-geostrophic Baroclinic Model: Analysis of Instabilities and Feedbacks

    Science.gov (United States)

    Schubert, Sebastian; Lucarini, Valerio

    2016-04-01

    The classical approach for studying atmospheric variability is based on defining a background state and studying the linear stability of the small fluctuations around such a state. Weakly non-linear theories can be constructed using higher order expansions terms. While these methods have undoubtedly great value for elucidating the relevant physical processes, they are unable to follow the dynamics of a turbulent atmosphere. We provide a first example of extension of the classical stability analysis to a non-linearly evolving quasi-geostrophic flow. The so-called covariant Lyapunov vectors (CLVs) provide a covariant basis describing the directions of exponential expansion and decay of perturbations to the non-linear trajectory of the flow. We use such a formalism to re-examine the basic barotropic and baroclinic processes of the atmosphere with a quasi-geostrophic beta-plane two-layer model in a periodic channel driven by a forced meridional temperature gradient ΔT . We explore three settings of ΔT , representative of relatively weak turbulence, well-developed turbulence, and intermediate conditions. We construct the Lorenz energy cycle for each CLV describing the energy exchanges with the background state. A positive baroclinic conversion rate is a necessary but not sufficient condition of instability. Barotropic instability is present only for few very unstable CLVs for large values of ΔT. Slowly growing and decaying hydrodynamic Lyapunov modes closely mirror the properties of the background flow. Following classical necessary conditions for barotropic/baroclinic instability, we find a clear relationship between the properties of the eddy fluxes of a CLV and its instability. CLVs with positive baroclinic conversion seem to form a set of modes for constructing a reduced model of the atmosphere dynamics.

  2. Analysis and Modeling of the Arctic Oscillation Using a Simple Barotropic Model with Baroclinic Eddy Forcing.

    Science.gov (United States)

    Tanaka, H. L.

    2003-06-01

    In this study, a numerical simulation of the Arctic Oscillation (AO) is conducted using a simple barotropic model that considers the barotropic-baroclinic interactions as the external forcing. The model is referred to as a barotropic S model since the external forcing is obtained statistically from the long-term historical data, solving an inverse problem. The barotropic S model has been integrated for 51 years under a perpetual January condition and the dominant empirical orthogonal function (EOF) modes in the model have been analyzed. The results are compared with the EOF analysis of the barotropic component of the real atmosphere based on the daily NCEP-NCAR reanalysis for 50 yr from 1950 to 1999.According to the result, the first EOF of the model atmosphere appears to be the AO similar to the observation. The annular structure of the AO and the two centers of action at Pacific and Atlantic are simulated nicely by the barotropic S model. Therefore, the atmospheric low-frequency variabilities have been captured satisfactorily even by the simple barotropic model.The EOF analysis is further conducted to the external forcing of the barotropic S model. The structure of the dominant forcing shows the characteristics of synoptic-scale disturbances of zonal wavenumber 6 along the Pacific storm track. The forcing is induced by the barotropic-baroclinic interactions associated with baroclinic instability.The result suggests that the AO can be understood as the natural variability of the barotropic component of the atmosphere induced by the inherent barotropic dynamics, which is forced by the barotropic-baroclinic interactions. The fluctuating upscale energy cascade from planetary waves and synoptic disturbances to the zonal motion plays the key role for the excitation of the AO.

  3. NON-ZONAL BAROCLINIC INSTABILITY IN THE NORTH PACIFIC SUBTROPICAL COUNTERCURRENT

    Institute of Scientific and Technical Information of China (English)

    LU Yan; LUO De-hai

    2004-01-01

    Observations indicated that in the region of the Subtropical Countercurrent(STCC)over the Pacific(140°E-170°W,19°N-28°N),the eddy kinetic energy over the western side is much higher than that over the eastern side.The cause of such a behavior was theoretically investigated in this paper.The calculation of geostrophic current in this region indicates that there are relatively strong meridional geostrophic currents in this region even though the zonal current is dominant in most seasons.Using a 2.5-layer reduced-gravity model,baroclinic instability of non-zonal current was discussed.It is found that at the western side of STCC the vertical shear of the meridional geostrophic current will be in favor of the baroclinic instability,but at its eastern side it will suppress baroclinic instability,thus causing the growth of eddies over the western side much faster than that over the eastern side.

  4. THE SEMI-GEOSTROPHIC ADAPTATION PROCESS WITH TWO-LAYER BAROCLINIC MODEL IN LOW LATITUDE ATMOSPHERE

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper, the adaptation process in low latitude atmosphere is discussed by means of a two-layer baroclinic model on the equator β plane, showing that the adaptation process in low latitude is mainly dominated by the internal inertial gravity waves. The initial ageostrophic energy is dispersed by the internal inertial gravity waves, and as a result, the geostrophic motion is obtained in zonal direction while the ageostrophic motion maintains in meridional direction, which can be called semi-geostrophic balance in barotropic model as well as semi-thermal-wind balance in baroclinic model. The vertical motion is determined both by the distribution of the initial vertical motion and that of the initial vertical motion tendency, but it is unrelated to the initial potential vorticity. Finally, the motion tends to be horizontal. The discussion of the physical mechanism of the semi-thermal-wind balance in low latitude atmosphere shows that the achievement of the semi-thermal-wind balance is due to the adjustment between the stream field and the temperature field through the horizontal convergence and divergence which is related to the vertical motion excited by the internal inertial gravity waves. The terminal adaptation state obtained shows that the adaptation direction between the mean temperature field and the shear flow field is determined by the ratio of the scale of the initial ageostrophic disturbance to the scale of one character scale related to the baroclinic Rossby radius of deformation. The shear stream field adapts to the mean temperature field when the ratio is greater than 1, and the mean temperature field adapts to the shear stream field when the ratio is smaller than 1.

  5. Generation of the North Equatorial Undercurrent Jets by Triad Baroclinic Rossby Wave Interactions (Invited)

    Science.gov (United States)

    Qiu, B.; Chen, S.; Sasaki, H.; Rudnick, D. L.

    2013-12-01

    Formation processes responsible for the North Equatorial Undercurrent (NEUC) jets that appear across the tropical North Pacific Ocean near 9N, 13N, and 18N, are explored both theoretically and using numerical models with different complexities. Analyses of an eddy-resolving global ocean general circulation model output reveal that the NEUC jets have a mode-1 baroclinic vertical structure and are spatially persistent on the interannual and longer time scales. This OGCM-simulated vertical structure prompts us to adopt the simpler, nonlinear 1.5-layer reduced-gravity model, as well as the baroclinic Rossby wave triad interaction theory, to unravel the essential processes underlying the NEUC jets. The seed for the NEUC jets originates in annual baroclinic Rossby waves driven by the large-scale surface wind stress forcing. Emanating from the ocean basin's eastern boundary, these wind-forced ``primary'' waves are subject to nonlinear triad interactions and break down offshore where the e-folding timescale of the most unstable triad instability matches the advective timescale of the primary waves. The break-down boundary of the wind-forced primary waves tends to tilt northeast-southwestward and, west of this boundary, finite-amplitude eddies emerge, whose meridional scales are set by the most unstable short secondary waves participating in the triad interactions along the break-down boundary. With their meridional scales set similarly by the short secondary waves, the time-mean zonal jets of characteristics resembling the observed NEUC jets are formed by the converging potential vorticity fluxes of these finite-amplitude eddies.

  6. The Sensitivity of Characteristics of Large Scale Baroclinic Unstable Waves in Southern Hemisphere to the Underlying Climate

    Directory of Open Access Journals (Sweden)

    Sergei Soldatenko

    2013-01-01

    Full Text Available The sensitivity of the main characteristics of baroclinically unstable waves with respect to fundamental parameters of the atmosphere (the static stability parameter σ0 and vertical shear of a zonal wind Λ is theoretically explored. Two types of waves are considered: synoptic scale waves and planetary scale (ultralong waves based on an Eady-type model and model with vertically averaged primitive equations. Sensitivity functions are obtained that estimate the impact of variations in σ0 and Λ on the growth rate and other characteristics of unstable waves and demonstrate that waves belonging to the short-wave part of the spectrum of unstable waves are more sensitive to changes in the static stability parameter than waves belonging to the long-wave part of the spectrum. The obtained theoretical results show that the increase of the static stability and decrease of the meridional temperature gradient in midlatitude baroclinic zones in some areas of the southern hemisphere lead to a slowing of the growth rate of baroclinic unstable waves and an increasing wavelength of baroclinic unstable wave maximum growth rate, that is, a spectrum shift of unstable waves towards longer wavelengths. These might affect the favorable conditions for the development of baroclinic instability and, therefore, the intensity of cyclone generation activity.

  7. Increase of upper troposphere/lower stratosphere wave baroclinicity during the second half of the 20th century

    Directory of Open Access Journals (Sweden)

    L. Gimeno

    2009-12-01

    Full Text Available A strengthening of the equatorward temperature gradient in the upper troposphere/lower stratosphere (UTLS, at subtropics and midlatitudes, is consistently reproduced in several modelling studies of the atmospheric response to the increase of greenhouse gas radiative forcing. Some of those studies suggest an increase of the baroclinicity in the UTLS region because of the enhanced meridional temperature gradient.

    This study presents observational evidence of an increase of the baroclinic wave components of UTLS circulation (UTLS wave baroclinicity, during the second half of the 20th century. The evidence is given by significant positive trends in the energy of baroclinic normal modes of the NCEP/NCAR reanalysis, and significant positive trends in the UTLS eddy available potential energy of the NCEP/NCAR, ERA-40, NCEP-2 and JRA-25 reanalyses. Significant positive trends in the frequency of double tropopause events in radiosonde data are also interpreted as a manifestation of an increase of the UTLS wave baroclinicity.

  8. Adjustment time of the first baroclinic Rossby wave in the global oceans

    Institute of Scientific and Technical Information of China (English)

    FAN Haimei; LI Bingrui; XU Ren; ZHANG Zhenglong; LI Yihong

    2006-01-01

    According to the freely linear Rossby wave theory, global 1°×1° climatology of Rossby deformation radius and phase speed are studied under the flat bottom fluid approximation. Geographical variations in the contours of the phase speed are very similar to those of the Rossby radius of formation, which are mainly affected by stratification, rotation, water depth, topography, etc. The basin-crossing time of the first baroclinic Rossby wave is obtained and analyzed in the global ocean basins. The results are useful to learn the importance of Rossby wave and the adiabatic adjustment of large-scale ocean circulation.

  9. The effects of oppositely sloping boundaries with Ekman dissipation in a nonlinear baroclinic system

    Science.gov (United States)

    Weng, H.-Y.

    1990-01-01

    The present analytical and numerical examination of the effect of the slope Delta with dissipation delta on baroclinic flows in linear and nonlinear systems uses a modified Eady channel model with oppositely sloping top and bottom Ekman layers, and truncates the spectral wave solution up to six components. Comparisons are made wherever possible with results from beta-plane dissipative systems. In the linear system, the combined effect of Delta and delta strongly stabilizes long waves. In a nonlinear system without wave-wave interaction, Delta stabilizes the flow even for small delta and reduces the domain of vacillation while enlarging the domain of single-wave steady state.

  10. Macro-scale turbulence modelling for flows in porous media; Modelisation a l'echelle macroscopique d'un ecoulement turbulent au sein d'un milieu poreux

    Energy Technology Data Exchange (ETDEWEB)

    Pinson, F

    2006-03-15

    - This work deals with the macroscopic modeling of turbulence in porous media. It concerns heat exchangers, nuclear reactors as well as urban flows, etc. The objective of this study is to describe in an homogenized way, by the mean of a spatial average operator, turbulent flows in a solid matrix. In addition to this first operator, the use of a statistical average operator permits to handle the pseudo-aleatory character of turbulence. The successive application of both operators allows us to derive the balance equations of the kind of flows under study. Two major issues are then highlighted, the modeling of dispersion induced by the solid matrix and the turbulence modeling at a macroscopic scale (Reynolds tensor and turbulent dispersion). To this aim, we lean on the local modeling of turbulence and more precisely on the k - {epsilon} RANS models. The methodology of dispersion study, derived thanks to the volume averaging theory, is extended to turbulent flows. Its application includes the simulation, at a microscopic scale, of turbulent flows within a representative elementary volume of the porous media. Applied to channel flows, this analysis shows that even within the turbulent regime, dispersion remains one of the dominating phenomena within the macro-scale modeling framework. A two-scale analysis of the flow allows us to understand the dominating role of the drag force in the kinetic energy transfers between scales. Transfers between the mean part and the turbulent part of the flow are formally derived. This description significantly improves our understanding of the issue of macroscopic modeling of turbulence and leads us to define the sub-filter production and the wake dissipation. A f - <{epsilon}>f - <{epsilon}{sub w}>f model is derived. It is based on three balance equations for the turbulent kinetic energy, the viscous dissipation and the wake dissipation. Furthermore, a dynamical predictor for the friction coefficient is proposed. This model is then

  11. The Predictability of Near-Coastal Currents Using a Baroclinic Unstructured Grid Model

    Science.gov (United States)

    2011-12-28

    continuity equation is solved for the vertical velocity, subject to kinematic boundary conditions (Luettich et al. 2002; Muccino et al. 1997). For the baro ...2001. J Atmos Ocean Tcchnol21(12):l876-l894 Barron CN, Kara A, Martin P, Rhodes R, Smedstad L (2006) Formulation, implementation and examination of...larval recruitment. Bull Mar Sei 57:726-738 Kara AB, Barron C, Martin P, Smedstad L, Rhodes R (2006) Validation of intcrannual simulations from the 1

  12. Baroclinic mixing of potential vorticity as the principal sharpening mechanism for the extratropical Tropopause Inversion Layer

    Science.gov (United States)

    Wang, Shu Meir; Geller, Marvin A.

    2016-09-01

    Previous works have shown that a dry, idealized general circulation model could produce many features of the extratropical Tropopause Inversion Layer (TIL). In particular, the following have been shown, but no explanations were given for these results. (1) A sharper extratropical TIL resulted more from increased horizontal resolution than from increased vertical resolution. (2) If the Equator-to-Pole temperature gradient was varied, the annual variation of the extratropical TIL found in observations could be reproduced. (3) The extratropical TIL altitude showed excellent correlation with the upper tropospheric relative vorticity, as had been previously proposed. (4) Increased horizontal model resolutions led to extratropical TILs that were at lower altitudes. We show that these conclusions follow from baroclinic mixing of high stratospheric potential vorticity into the troposphere being the principal sharpening mechanism for the extratropical TIL and the increased baroclinic activity occurring in higher horizontal resolution models. We furthermore suggest that the distance from the jet exerts a greater influence on the height and sharpness of the extratropical TIL than does the upper tropospheric relative vorticity, and this accounts for the annual behavior of the extratropical TIL found in observations and reproduced with a dry, mechanistic, global model.

  13. The available-enthalpy (flow-exergy) cycle. Part-II: applications to idealized baroclinic waves

    CERN Document Server

    Marquet, Pascal

    2014-01-01

    The local available-enthalpy cycle proposed in Part I of this paper is applied to document energetics of three numerical simulations, representing life cycles of idealized baroclinic waves. An improved temporal numerical scheme defined in Part I is used in this study, together with the Arpege-IFS model using a T42 triangular truncation. A 45{\\deg}N and 200 hPa dry unstable jet is constructed with the most unstable mode at zonal wave number 8. Energetic impacts of both horizontal and vertical diffusion schemes are determined separately. The role of ageostrophic winds within the Ekman layer is investigated, leading to an explanation for large observed values for the dissipation terms and to a new formulation of the potential-energy conversions. The magnitudes of these new conversion terms are compared with those of the usual barotropic and baroclinic conversions. A new version for the available-enthalpy cycle is proposed. It is suitable for open systems and it includes explicitly the potential-energy component ...

  14. Short-term fluctuations in the eddy heat flux and baroclinic stability of the atmosphere

    Science.gov (United States)

    Stone, P. H.; Ghan, S. J.; Spiegel, D.; Rambaldi, S.

    1982-01-01

    National Meteorological Center data from midlatitudes for three Januaries is used in calculating time series of the zonal mean meridional eddy heat flux and the zonal mean baroclinic stability, as measured by the difference between the zonal wind shear and the critical value of the shear in two-level models. Time-lagged correlations between the two series reveal a highly significant negative correlation for short time lags, peaking at approximately -0.4 when the stability parameter lags one half day behind the eddy flux. They also reveal that strongly unstable conditions are not followed by significant increases in the eddy flux. These results are seen as indicating that the synoptic variations of the zonal mean eddy flux are not closely related to the degree of baroclinic instability of the zonal mean flow. The autocorrelation of the eddy flux is then compared with those expected for autoregressive processes. A Bayesian information criterion suggests that the behavior is represented best by a damped oscillation, with a damping time of 0.8 day and a period of five days.

  15. Experiments on transitions of baroclinic waves in a differentially heated rotating annulus

    Directory of Open Access Journals (Sweden)

    Th. von Larcher

    2005-01-01

    Full Text Available Experiments of baroclinic waves in a rotating, baroclinic annulus of fluid are presented for two gap widths. The apparatus is a differentially heated cylindrical gap, rotated around its vertical axis of symmetry, cooled from within, with a free surface, and filled with de-ionised water as working fluid. The surface flow was observed with visualisation technique while thermographic measurements gave a detailed understanding of the temperature distribution and its time-dependent behaviour. We focus in particular on transitions between different flow regimes. Using a wide gap, the first transition from axisymmetric flow to the regular wave regime was characterised by complex flows. The transition to irregular flows was smooth, where a coexistence of the large-scale jet-stream and small-scale vortices was observed. Furthermore, temperature measurements showed a repetitive separation of cold vortices from the inner wall. Experiments using a narrow gap showed no complex flows but strong hysteresis in the steady wave regime, with up to five different azimuthal wave modes as potential steady and stable solutions.

  16. Baroclinic Vortices in Rotating Stratified Shearing Flows: Cyclones, Anticyclones, and Zombie Vortices

    Science.gov (United States)

    Hassanzadeh, Pedram

    Large coherent vortices are abundant in geophysical and astrophysical flows. They play significant roles in the Earth's oceans and atmosphere, the atmosphere of gas giants, such as Jupiter, and the protoplanetary disks around forming stars. These vortices are essentially three-dimensional (3D) and baroclinic, and their dynamics are strongly influenced by the rotation and density stratification of their environments. This work focuses on improving our understanding of the physics of 3D baroclinic vortices in rotating and continuously stratified flows using 3D spectral simulations of the Boussinesq equations, as well as simplified mathematical models. The first chapter discusses the big picture and summarizes the results of this work. In Chapter 2, we derive a relationship for the aspect ratio (i.e., vertical half-thickness over horizontal length scale) of steady and slowly-evolving baroclinic vortices in rotating stratified fluids. We show that the aspect ratio is a function of the Brunt-Vaisala frequencies within the vortex and outside the vortex, the Coriolis parameter, and the Rossby number of the vortex. This equation is basically the gradient-wind equation integrated over the vortex, and is significantly different from the previously proposed scaling laws that find the aspect ratio to be only a function of the properties of the background flow, and independent of the dynamics of the vortex. Our relation is valid for cyclones and anticyclones in either the cyclostrophic or geostrophic regimes; it works with vortices in Boussinesq fluids or ideal gases, and non-uniform background density gradient. The relation for the aspect ratio has many consequences for quasi-equilibrium vortices in rotating stratified flows. For example, cyclones must have interiors more stratified than the background flow (i.e., super-stratified), and weak anticyclones must have interiors less stratified than the background (i.e., sub-stratified). In addition, this equation is useful to

  17. A process study of the Adriatic-Ionian System baroclinic dynamics

    Science.gov (United States)

    Reale, M.; Crise, A.; Farneti, R.; Mosetti, R.

    2016-08-01

    The driving mechanisms behind the decadal reversal of the Ionian Sea upper layer circulation recently sparked a considerable discussion in the Mediterranean scientific community. It has been suggested that the reversal can be driven by variations in wind stress curl over the basin, baroclinic dynamics acting within the Adriatic-Ionian System (AISys) or baroclinic dynamics driven by thermohaline properties at the AISys eastern boundary. Here we perform numerical simulations in order to assess the relative importance of remote forcings (wind stress, thermohaline fluxes, thermohaline open boundary conditions) on the vorticity and energy budget of the Ionian Sea. A mechanistic understanding of the AISys dynamics is achieved with an approach based on an increasing complexity in the model forcings and domain. Our experiments suggest that wind stress does not play a leading role in the vorticity and energy budgets of the Ionian Sea. Wind stress can reinforce or weaken the circulation but it is not able to reverse its sign. Its role becomes dominant only in the absence of inflows through the Antikythira Strait and Cretan Passage. Instead, reversals in the upper layer circulation of the Ionian Sea take place only in the presence of an active boundary on the Aegean Sea/Levantine Basin side and appear to be correlated with substantial exchanges of Availalble Potential Energy between the two basins (as observed at the end of the Eastern Mediterranean Transient). From an energetic point of view, AISys can be explained therefore only if the role of the Aegean Sea is explicitly considered.

  18. Benchmarking in a rotating annulus: a comparative experimental and numerical study of baroclinic wave dynamics

    Directory of Open Access Journals (Sweden)

    Miklos Vincze

    2015-01-01

    Full Text Available The differentially heated rotating annulus is a widely studied tabletop-size laboratory model of the general mid-latitude atmospheric circulation. The two most relevant factors of cyclogenesis, namely rotation and meridional temperature gradient are quite well captured in this simple arrangement. The radial temperature difference in the cylindrical tank and its rotation rate can be set so that the isothermal surfaces in the bulk tilt, leading to the formation of baroclinic waves. The signatures of these waves at the free water surface have been analyzed via infrared thermography in a wide range of rotation rates (keeping the radial temperature difference constant and under different initial conditions. In parallel to the laboratory experiments, five groups of the MetStröm collaboration have conducted numerical simulations in the same parameter regime using different approaches and solvers, and applying different initial conditions and perturbations. The experimentally and numerically obtained baroclinic wave patterns have been evaluated and compared in terms of their dominant wave modes, spatio-temporal variance properties and drift rates. Thus certain “benchmarks” have been created that can later be used as test cases for atmospheric numerical model validation.

  19. Optimization strategy of communication performance in 2D macro-scale pseudo-particle parallel simulation%二维宏观拟颗粒并行模拟程序通信性能优化策略

    Institute of Scientific and Technical Information of China (English)

    严历; 郭力

    2009-01-01

    As the application of particle simulation parallel computing becomes more and more widely used, the communication per-formances in the particle simulation parallel programs can significantly affect the simulation performances when the parallel scale increa-ses, which even may become the major performance bottleneck of the simulation. Based on the analysis of the factors that may affect the communication performances in parallel programs, optimization tests on process partitioning and communication protocol for the commu-nication performance in a 2D macro-scale pseudo-particle parallel simulation program, a typical particle simulation parallel program have been done on Gigabit Etheroet. With improved process partitioning and use of user-level communication protocol, communication performance of the testing program has been enhanced. Some communication performance optimization strategies for particle simulation parallel programs are also proposed in the paper.%随着粒子模拟并行计算在相关领域应用的不断深入和并行节点计算能力的不断增强,粒子模拟并行程序中通信耗时对整体性能的影响越来越显著,甚至成为主要性能瓶颈.本文在分析影响并行程序通信性能多种因素的基础上,从进程划分方式选择、通信协议优化的角度,对1个典型粒子模拟并行程序——二维宏观拟颗粒并行模拟程序在千兆以太网环境下的通信性能的优化策略进行了测试研究,通过改进并行进程划分方式,采用用户级通信协议等方法,使测试程序通信性能获得明显提高,进而提出了粒子模拟并行程序通信性能优化的思路和建议.

  20. Multivariate statistical data analysis methods for detecting baroclinic wave interactions in the thermally driven rotating annulus

    Science.gov (United States)

    von Larcher, Thomas; Harlander, Uwe; Alexandrov, Kiril; Wang, Yongtai

    2010-05-01

    Experiments on baroclinic wave instabilities in a rotating cylindrical gap have been long performed, e.g., to unhide regular waves of different zonal wave number, to better understand the transition to the quasi-chaotic regime, and to reveal the underlying dynamical processes of complex wave flows. We present the application of appropriate multivariate data analysis methods on time series data sets acquired by the use of non-intrusive measurement techniques of a quite different nature. While the high accurate Laser-Doppler-Velocimetry (LDV ) is used for measurements of the radial velocity component at equidistant azimuthal positions, a high sensitive thermographic camera measures the surface temperature field. The measurements are performed at particular parameter points, where our former studies show that kinds of complex wave patterns occur [1, 2]. Obviously, the temperature data set has much more information content as the velocity data set due to the particular measurement techniques. Both sets of time series data are analyzed by using multivariate statistical techniques. While the LDV data sets are studied by applying the Multi-Channel Singular Spectrum Analysis (M - SSA), the temperature data sets are analyzed by applying the Empirical Orthogonal Functions (EOF ). Our goal is (a) to verify the results yielded with the analysis of the velocity data and (b) to compare the data analysis methods. Therefor, the temperature data are processed in a way to become comparable to the LDV data, i.e. reducing the size of the data set in such a manner that the temperature measurements would imaginary be performed at equidistant azimuthal positions only. This approach initially results in a great loss of information. But applying the M - SSA to the reduced temperature data sets enable us to compare the methods. [1] Th. von Larcher and C. Egbers, Experiments on transitions of baroclinic waves in a differentially heated rotating annulus, Nonlinear Processes in Geophysics

  1. Generation of large-scale intrusions at baroclinic fronts: an analytical consideration with a reference to the Arctic Ocean

    Science.gov (United States)

    Kuzmina, Natalia

    2016-12-01

    Analytical solutions are found for the problem of instability of a weak geostrophic flow with linear velocity shear accounting for vertical diffusion of buoyancy. The analysis is based on the potential-vorticity equation in a long-wave approximation when the horizontal scale of disturbances is considered much larger than the local baroclinic Rossby radius. It is hypothesized that the solutions found can be applied to describe stable and unstable disturbances of the planetary scale with respect, in particular, to the Arctic Ocean, where weak baroclinic fronts with typical temporal variability periods on the order of several years or more have been observed and the β effect is negligible. Stable (decaying with time) solutions describe disturbances that, in contrast to the Rossby waves, can propagate to both the west and east, depending on the sign of the linear shear of geostrophic velocity. The unstable (growing with time) solutions are applied to explain the formation of large-scale intrusions at baroclinic fronts under the stable-stable thermohaline stratification observed in the upper layer of the Polar Deep Water in the Eurasian Basin. The suggested mechanism of formation of intrusions can be considered a possible alternative to the mechanism of interleaving at the baroclinic fronts due to the differential mixing.

  2. Baroclinic pressure gradient difference schemes of subtracting the local averaged density stratification in sigma coordinates models

    Institute of Scientific and Technical Information of China (English)

    ZHU Shouxian; ZHANG Wenjing

    2008-01-01

    Much has been written of the error in computing the baroclinic pressure gradient (BPG) with sigma coordinates in ocean or atmos- pheric numerical models. The usual way to reduce the error is to subtract area-averaged density stratification of the whole computa- tion region. But if there is great difference between the area-averaged and the local averaged density stratification, the error will be obvious. An example is given to show that the error from this method may be larger than that from no correction sometimes. The definition of local area is put forward. Then, four improved BPG difference schemes of subtracting the local averaged density strat- ification are designed to reduce the error. Two of them are for diagnostic calculation (density field is fixed), and the others are for prognostic calculation (density field is not fixed). The results show that the errors from these schemes all significantly decrease.

  3. The radiative zone of the Sun and the tachocline: stability of baroclinic patterns of differential rotation

    CERN Document Server

    Caleo, Andrea

    2016-01-01

    Barotropic rotation and radiative equilibrium are mutually incompatible in stars. The issue is often addressed by allowing for a meridional circulation, but this is not devoid of theoretical complications. Models of rotation in the Sun which maintain strict radiative equilibrium, making use of the observation that the Sun is not in a state of barotropic rotation, have recently been suggested. To investigate the dynamical behaviour of these solutions, we study the local stability of stratified, weakly magnetized, differentially rotating fluids to non-axisymmetric perturbations. Finite heat conductivity, kinematic viscosity, and resistivity are present. The evolution of local embedded perturbations is governed by a set of coupled, ordinary differential equations with time-dependent coefficients. Two baroclinic models of rotation for the upper radiative zone and tachocline are studied: (i) an interpolation based on helioseismology data, (ii) a theoretical solution directly compatible with radiative equilibrium. ...

  4. NUMERICAL STUDY ON THE FORMATION OF THE SOUTH CHINA SEA WARM CURRENT Ⅱ. BAROCLINIC CASE

    Institute of Scientific and Technical Information of China (English)

    王凯; 方国洪; 施心慧

    2001-01-01

    In this part, Levitus' climatological temperature and salinity are incorporated in the numerical model developed in Part I. Diagnostic and prognostic experiment on the thermohaline circulation were conducted. The smooth Levitus' data do not include any information on the South China Sea Warm Current (SCSWC), so it is not in the model-produced diagnostic thermohaline circulation. Although the SCSWC does not appear in the wind-driven circulation in the barotropic case, it appears in the prognostic wind-driven circulation in the baroclinic case. This implies that the differing circulation pat-terns between barotropic case and bareclinic case are due to the stratification. The prognostic thermohaline circulation with wind stress and inflow/outflow transports at open boundaries are also discussed. Coupling of density and dynamic forces makes the circulation pattern more complicated, Even though the stratification is not always a direct cause of the formation of the SCSWC, it is at least an indirect cause.

  5. Lateral baroclinic forcing enhances sediment transport from shallows to channel in an estuary

    Science.gov (United States)

    Lacy, Jessica R.; Gladding, Steve; Brand, Andreas; Collignon, Audric; Stacey, Mark

    2014-01-01

    We investigate the dynamics governing exchange of sediment between estuarine shallows and the channel based on field measurements at eight stations spanning the interface between the channel and the extensive eastern shoals of South San Francisco Bay. The study site is characterized by longitudinally homogeneous bathymetry and a straight channel, with friction more important than the Coriolis forcing. Data were collected for 3 weeks in the winter and 4 weeks in the late summer of 2009, to capture a range of hydrologic and meteorologic conditions. The greatest sediment transport from shallows to channel occurred during a pair of strong, late-summer wind events, with westerly winds exceeding 10 m/s for more than 24 h. A combination of wind-driven barotropic return flow and lateral baroclinic circulation caused the transport. The lateral density gradient was produced by differences in temperature and suspended sediment concentration (SSC). During the wind events, SSC-induced vertical density stratification limited turbulent mixing at slack tides in the shallows, increasing the potential for two-layer exchange. The temperature- and SSC-induced lateral density gradient was comparable in strength to salinity-induced gradients in South Bay produced by seasonal freshwater inflows, but shorter in duration. In the absence of a lateral density gradient, suspended sediment flux at the channel slope was directed towards the shallows, both in winter and during summer sea breeze conditions, indicating the importance of baroclinically driven exchange to supply of sediment from the shallows to the channel in South San Francisco Bay and systems with similar bathymetry.

  6. Tropopause inversion layer formation and stratosphere-troposphere exchange during idealized baroclinic wave life cycle experiments

    Science.gov (United States)

    Kunkel, Daniel; Wirth, Volkmar; Hoor, Peter

    2014-05-01

    Recent simulations of baroclinic wave life cycles revealed that the tropopause inversion layer (TIL), commonly situated just above the thermal tropopause, is evident in such experiments and emerges after the onset of wave breaking. Furthermore, bidirectional stratosphere-troposphere exchange (STE) occurs during this non-linear stage of the wave evolution and might be affected by the appearance of the TIL. We study the evolution and the impact of the TIL on STE by using the COSMO model in an idealized mid-latitude channel geometry configuration without physical sub-grid scale parameterizations. We initialize the model with a geostrophically balanced upper level jet stream which is disturbed by an anomaly of potential vorticity to trigger the evolution of the baroclinic waves. Moreover, we use passive tracers of tropospheric or stratospheric origin to identify regions of potential STE. Our results show that the static stability is low in regions of stratosphere to troposphere exchange (STT), while it is high in regions dominated by exchange in the opposite direction (TST). Furthermore, inertia gravity waves, originating from regions with strong ageostrophic wind components, modulate the static stability as well as the vertical shear of the horizontal wind near and above the tropopause. While propagating away from their source, the inertia gravity waves lead to large values of the squared Brunt Vaisala frequency in regions which are simultaneously characterized by low bulk Richardson numbers. Thus, these regions are statically stable and turbulent at the same time and might be crucial for TST, thereby explaining tropospheric mixing ratio changes of e.g. CO across the tropopause which commonly change from tropospheric to stratospheric values a few hundred meters above the local thermal tropopause.

  7. Effects of surface drag on low-level frontogenesis within baroclinic waves

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yi; TAN ZheMin

    2007-01-01

    Using a three-dimensional nonhydrostatic mesoscale numerical model (MM5), the evolution and structures of baroclinic waves with and without surface drag in case of dry and moist atmosphere are simulated, with special emphases on the effects of surface drag on the low-level frontal structure and frontogenesis. There are two different effects of surface drag on the low-level frontogenesis in the dry case. On one hand, the surface drag weakens the low-level frontogenesis and less inclined to develop the baroclinic wave due to the dissipation. But on the other hand, the surface drag induces a strong ageostrophic flow, which prolongs the low-level frontogenesis and finally leads to the enhancement of cold front. Compared with the no surface drag case, the surface drag increases the frontal slope especially in the boundary layer, where the front is almost vertical to the surface, and then enhances the prefrontal vertical motion. All these conclusions expanded the analytical theory of Tan and Wu (1990). In the moist atmosphere, the influence of surface drag on frontal rainbands is also obvious. The surface drag weakens the convection, and reduces the energy dissipation near the surface when the initial relative humidity is relatively weak. At this time, the confluence induced post-frontal updrafts moves across the cold front and reinforces the prefrontal convection, which is beneficial to the maintenance of the rainband in cold sector. Given the enhancement of relative humidity, the moist convection dominates the low-level frontogenesis while the retardation of surface drag on energy dissipation is not obvious, therefore the effects of surface drag on the low-level frontogenesis and precipitation are reduced.

  8. Detection of Northern Hemisphere Transient Baroclinic Eddies in REMS Pressure Data at Gale Crater Mars

    Science.gov (United States)

    Haberle, Robert; Kahre, Melinda A.; De la Torre, Manuel; Kass, David M.; Mars Science Laboratory Science Team

    2016-10-01

    Wintertime transient baroclinic eddies in the northern midlatitudes of Mars were identified in Viking Lander 2 (VL2, 48.3N, 134.0E) surface pressure data back in the early 1980s. Here we report the results of an analysis of REMS surface pressure data acquired by the Curiosity Rover in Gale Crater (4.5S, 137.4E) that suggests the meridional scale of these eddies is so large that the disturbances in the surface pressure fields they create extend across the equator and into the southern hemisphere. A power spectrum analysis of the seasonally detrended REMS pressure data from Ls=240-280 shows dominant periods of ~ 6 sols and ~2.2 sols (though with greatly reduced power) which are close the dominant periods of the transient eddies observed by VL2 at this season. Analysis of the surface pressure fields from the Ames Mars GCM for the same season also shows dominant periods at the grid points closest to VL2 and Gale Crater similar to those observed. In the model, the disturbances responsible for these oscillations are eastward traveling baroclinic eddies whose amplitudes are greatest at northern mid latitudes at this season, but whose meridional extent does indeed extend into the low latitudes of the southern hemisphere. REMS appears to be seeing the signature of these eddies, not only for this season but for the early fall and late winter seasons as well. While orbital images of the so called "flushing storms", which more closely correspond to the shorter period waves, show dust-lifting frontal systems that cross the equator, REMS data - even though acquired at a longitude of comparatively weak storm activity - provide the first in-situ evidence that northern hemisphere transient eddies can be detected at the surface in low latitudes of the southern hemisphere.

  9. Atmospheric-like rotating annulus experiment: gravity wave emission from baroclinic jets

    Science.gov (United States)

    Rodda, Costanza; Borcia, Ion; Harlander, Uwe

    2017-04-01

    agreement for the large scale baroclinic wave regime. Moreover, in both cases a clear signal of horizontal divergence, embedded in the baroclinic wave front, appears suggesting IGWs emission.

  10. Effects of surface drag on low-level frontogenesis within baroclinic waves

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Using a three-dimensional nonhydrostatic mesoscale numerical model (MM5), the evolution and structures of baroclinic waves with and without surface drag in case of dry and moist atmosphere are simulated, with special emphases on the effects of surface drag on the low-level frontal structure and frontogenesis. There are two different effects of surface drag on the low-level frontogenesis in the dry case. On one hand, the surface drag weakens the low-level frontogenesis and less inclined to develop the baroclinic wave due to the dissipation. But on the other hand, the surface drag induces a strong ageostrophic flow, which prolongs the low-level frontogenesis and finally leads to the enhancement of cold front. Compared with the no surface drag case, the surface drag increases the frontal slope espe- cially in the boundary layer, where the front is almost vertical to the surface, and then enhances the prefrontal vertical motion. All these conclusions expanded the analytical theory of Tan and Wu (1990). In the moist atmosphere, the influence of surface drag on frontal rainbands is also obvious. The surface drag weakens the convection, and reduces the energy dissipation near the surface when the initial relative humidity is relatively weak. At this time, the confluence induced post-frontal updrafts moves across the cold front and reinforces the prefrontal convection, which is beneficial to the maintenance of the rainband in cold sector. Given the enhancement of relative humidity, the moist convection domi- nates the low-level frontogenesis while the retardation of surface drag on energy dissipation is not obvious, therefore the effects of surface drag on the low-level frontogenesis and precipitation are re- duced.

  11. Baroclinic wave configurations evolution at European scale in the period 1948-2013

    Science.gov (United States)

    Carbunaru, Daniel; Burcea, Sorin; Carbunaru, Felicia

    2016-04-01

    The main aim of the study was to investigate the dynamic characteristics of synoptic configurations at European scale and especially in south-eastern part of Europe for the period 1948-2013. Using the empirical orthogonal functions analysis, simultaneously applied to daily average geopotential field at different pressure levels (200 hPa, 300 hPa, 500 hPa and 850 hPa) during warm (April-September) and cold (October-March) seasons, on a synoptic spatial domain centered on Europe (-27.5o lon V to 45o lon E and 32.5o lat N to 72.5o lat N), the main mode of oscillation characteristic to vertical shift of mean baroclinic waves was obtained. The analysis independently applied on 66 years showed that the first eigenvectors in warms periods describe about 60% of the data and in cold season 40% of the data for each year. In comparison secondary eigenvectors describe up to 20% and 10% of the data. Thus, the analysis was focused on the complex evolution of the first eigenvector in 66 years, during the summer period. On average, this eigenvector describes a small vertical phase shift in the west part of the domain and a large one in the eastern part. Because the spatial extent of the considered synoptic domain incorporates in the west part AMO (Atlantic Multidecadal Oscillation) and NAO (North Atlantic Oscillation) oscillations, and in the north part being sensitive to AO (Arctic Oscillation) oscillation, these three oscillations were considered as modulating dynamic factors at hemispherical scale. The preliminary results show that in the summer seasons AMO and NAO oscillations modulated vertical phase shift of baroclinic wave in the west of the area (Northwestern Europe), and the relationship between AO and NAO oscillations modulated vertical phase shift in the southeast area (Southeast Europe). Second, it was shown the way in which this vertical phase shift modulates the overall behavior of cyclonic activity, particularly in Southeastern Europe. This work has been developed

  12. Double-diffusive convection and baroclinic instability in a differentially heated and initially stratified rotating system: the barostrat instability

    CERN Document Server

    Vincze, Miklos; Harlander, Uwe; Gal, Patrice Le

    2016-01-01

    A water-filled differentially heated rotating annulus with initially prepared stable vertical salinity profiles is studied in the laboratory. Based on two-dimensional horizontal particle image velocimetry (PIV) data, and infrared camera visualizations, we describe the appearance and the characteristics of the baroclinic instability in this original configuration. First, we show that when the salinity profile is linear and confined between two non stratified layers at top and bottom, only two separate shallow fluid layers can be destabilized. These unstable layers appear nearby the top and the bottom of the tank with a stratified motionless zone between them. This laboratory arrangement is thus particularly interesting to model geophysical or astrophysical situations where stratified regions are often juxtaposed to convective ones. Then, for more general but stable initial density profiles, statistical measures are introduced to quantify the extent of the baroclinic instability at given depths and to analyze t...

  13. Double-diffusive convection and baroclinic instability in a differentially heated and initially stratified rotating system: the barostrat instability

    Science.gov (United States)

    Vincze, Miklos; Borcia, Ion; Harlander, Uwe; Le Gal, Patrice

    2016-12-01

    A water-filled differentially heated rotating annulus with initially prepared stable vertical salinity profiles is studied in the laboratory. Based on two-dimensional horizontal particle image velocimetry data and infrared camera visualizations, we describe the appearance and the characteristics of the baroclinic instability in this original configuration. First, we show that when the salinity profile is linear and confined between two non-stratified layers at top and bottom, only two separate shallow fluid layers can be destabilized. These unstable layers appear nearby the top and the bottom of the tank with a stratified motionless zone between them. This laboratory arrangement is thus particularly interesting to model geophysical or astrophysical situations where stratified regions are often juxtaposed to convective ones. Then, for more general but stable initial density profiles, statistical measures are introduced to quantify the extent of the baroclinic instability at given depths and to analyze the connections between this depth-dependence and the vertical salinity profiles. We find that, although the presence of stable stratification generally hinders full-depth overturning, double-diffusive convection can lead to development of multicellular sideways convection in shallow layers and subsequently to a multilayered baroclinic instability. Therefore we conclude that by decreasing the characteristic vertical scale of the flow, stratification may even enhance the formation of cyclonic and anticyclonic eddies (and thus, mixing) in a local sense.

  14. Theories of multiple equilibria and weather regimes : A critical reexamination. II - Baroclinic two-layer models

    Science.gov (United States)

    Cehelsky, Priscilla; Tung, Ka Kit

    1987-01-01

    Previous results based on low- and intermediate-order truncations of the two-layer model suggest the existence of multiple equilibria and/or multiple weather regimes for the extratropical large-scale flow. The importance of the transient waves in the synoptic scales in organizing the large-scale flow and in the maintenance of weather regimes was emphasized. The result shows that multiple equilibria/weather regimes that are present in lower-order models examined disappear when a sufficient number of modes are kept in the spectral expansion of the solution to the governing partial differential equations. Much of the chaotic behavior of the large-scale flow that is present in intermediate-order models is now found to be spurious. Physical reasons for the drastic modification are offered. A peculiarity in the formulation of most existing two-layer models is noted that also tends to exaggerate the importance of baroclinic processes and increase the degree of unpredictability of the large-scale flow.

  15. Application of a sigma-coordinate baroclinic model to the Baltic Sea

    Directory of Open Access Journals (Sweden)

    Andrzej Jankowski

    2002-03-01

    Full Text Available A three-dimensional (3-D sigma-coordinate baroclinic model is used to investigate water circulation and thermohaline variability in the Baltic Sea. Two versions of the horizontal resolution of ~ 10 km and ~ 5 km with 24 sigma-levels in the vertical are considered. The model is based on the Princeton Ocean Model code of Blumberg & Mellor (1987 and Mellor (1993, known as POM. This paper presents details of simulation strategies and briefly discusses the 'reality' of the results of modelling. The model's capabilities of simulating the characteristic hydrographic features of the Baltic Sea were tested for 3 months (August-October 1995, a simulation related to the period of the PIDCAP'95 experiment (Pilot Study for Intensive Data Collection and Analysis and Precipitation (Isemer 1996. The model results are compared with the in situ measurements of temperature and salinity at selected hydrographic stations, collected during cruises of r/v 'Oceania' in September and October 1995. Comparison of computed and measured temperature and salinity shows that the model reproduces the vertical structure of seawater temperature and salinity in relatively good accordance with the in situ observations. The differences between the calculated and observed values of temperature and salinity are c. 1-2oC and c. 1-2 PSU, depending on the location of the hydrographic station.

  16. Coastal Submesoscale Baroclinic Eddies in Cyclostrophic Balance in the Saguenay Fjord.

    Science.gov (United States)

    Livernoche, Alexandre; Bourgault, Daniel; Chavanne, Cédric; Galbraith, Peter

    2016-04-01

    Submesoscale baroclinic eddies in cyclostrophic balance were studied in the Saguenay fjord (Quebec, Canada) using mooring data, boat-based sampling and oblique images taken from the shore, obtained in 2013 and 2015. Cyclostrophic balance implies equilibrium between the centrifugal force and the pressure gradient, with negligible Coriolis effect. The shear between the strong ebb flow and the bathymetric obstacle of a cape in the fjord creates a front downstream from the cape, which in turn generates vortices that are hundreds of meters in diameter. Shipborne ADCP, echosounder and CTD transects across the front were measured in order to understand the eddy generation. The first observed vortex had a radius of ~175 m, a maximum horizontal velocity of 0.3 m/s, and was trapped above the pycnocline. The horizontal surface currents were determined using Particle Imagery Velocimetry (PIV) applied to successive georectified images. It was found that under some conditions, sea surface patterns can provide sufficiently clear information to quantitatively capture the eddy current field and its evolution over time. From these observations, the vertical vorticity field as well as the horizontal strain rate can be computed. These results, although preliminary, are promising for investigating horizontal eddy diffusion in coastal waters, as well as their parameterization in ocean.

  17. PRELIMINARY STUDY ON RELATIONSHIP BETWEEN DOUBLE VORTICES SELF-ORGANIZATION AND TYPHOON FORMATION IN BAROCLINIC ENVIRONMENT

    Institute of Scientific and Technical Information of China (English)

    TENG Dai-gao; LUO Zhe-xian; PAN Jing-song; YU Hui

    2010-01-01

    The relationship between the self-organization of double vortices(SODVs)and the formation of typhoons was discussed based on six numerical experiments with the Fifth-Generation National Center for Atmospheric Research/Penn State Mesoscale Model(MM5)and further discussion was made with a real typhoon case.The results showed that there is a critical distance dc for SODVs in baroclinic atmosphere.When the distance between separated vortices is smaller than or equal to dc,the double vortices self-organize into a typhoon-like vortex with two spiral bands.But the double vortices cannot have such organization if the distance between them is larger than dc.The value of dc is about 380 km in the context of ideal conditions in this paper,larger than that achieved in a barotropic model.A typical typhoon case in2005(Haitang)was selected to verify the above-mentioned conclusions.It was found that the SODV is one of the important and typical ways for the formation of typhoons.

  18. 3-D BAROCLINIC NUMERICAL SIMULATION OF THE SOUTH CHINA SEA I. UPPER CIRCULATION

    Institute of Scientific and Technical Information of China (English)

    蔡树群; 甘子钧; 刘秦玉

    2001-01-01

    A three-dimensional baroclinic shelf sea model was employed to simulate the seasonal characteristics of the South China Sea (SCS) upper circulation. The results showed that: in summer, an anticyclonic eddy, after its formation between the Bashi Channel and Dongsha Islands in the northeastern SCS, moves southwestward until it disperses slowly. There exists a northward western boundary current along the east shore of the Indo-China Peninsula in the western SCS and an anticyclonic gyre in the southern SCS. But at the end of summer and beginning of autumn, a weak local cyclonic eddy forms in the Nansha Trough, then grows slowly and moves westward till it becomes a cyclonic gyre in the southern SCS in autumn. At the beginning of winter, there exists a cyclonic gyre in the northern and southern SCS, and there is a southward western boundary current along the east shore of the Indo-China Peninsula. But at the end of winter, an anticyclonic eddy grows and moves toward the western boundary after forming in the Nansha Trough. The eddy's movement induces a new opposite sign eddy on its eastern side, while the strength of the southward western boundary current gets weakened. This phenomenon continues till spring and causes eddies in the southern SCS.

  19. Variational energy principle for compressible, baroclinic flow. 2: Free-energy form of Hamilton's principle

    Science.gov (United States)

    Schmid, L. A.

    1977-01-01

    The first and second variations are calculated for the irreducible form of Hamilton's Principle that involves the minimum number of dependent variables necessary to describe the kinetmatics and thermodynamics of inviscid, compressible, baroclinic flow in a specified gravitational field. The form of the second variation shows that, in the neighborhood of a stationary point that corresponds to physically stable flow, the action integral is a complex saddle surface in parameter space. There exists a form of Hamilton's Principle for which a direct solution of a flow problem is possible. This second form is related to the first by a Friedrichs transformation of the thermodynamic variables. This introduces an extra dependent variable, but the first and second variations are shown to have direct physical significance, namely they are equal to the free energy of fluctuations about the equilibrium flow that satisfies the equations of motion. If this equilibrium flow is physically stable, and if a very weak second order integral constraint on the correlation between the fluctuations of otherwise independent variables is satisfied, then the second variation of the action integral for this free energy form of Hamilton's Principle is positive-definite, so the action integral is a minimum, and can serve as the basis for a direct trail and error solution. The second order integral constraint states that the unavailable energy must be maximum at equilibrium, i.e. the fluctuations must be so correlated as to produce a second order decrease in the total unavailable energy.

  20. Enhanced Atlantic subpolar gyre variability through baroclinic threshold in a coarse resolution model

    Directory of Open Access Journals (Sweden)

    M. Mengel

    2012-11-01

    Full Text Available Direct observations, satellite measurements and paleo records reveal strong variability in the Atlantic subpolar gyre on various time scales. Here we show that variations of comparable amplitude can only be simulated in a coupled climate model in the proximity of a dynamical threshold. The threshold and the associated dynamic response is due to a positive feedback involving increased salt transport in the subpolar gyre and enhanced deep convection in its centre. A series of sensitivity experiments is performed with a coarse resolution ocean general circulation model coupled to a statistical-dynamical atmosphere model which in itself does not produce atmospheric variability. To simulate the impact of atmospheric variability, the model system is perturbed with freshwater forcing of varying, but small amplitude and multi-decadal to centennial periodicities and observational variations in wind stress. While both freshwater and wind-stress-forcing have a small direct effect on the strength of the subpolar gyre, the magnitude of the gyre's response is strongly increased in the vicinity of the threshold. Our results indicate that baroclinic self-amplification in the North Atlantic ocean can play an important role in presently observed SPG variability and thereby North Atlantic climate variability on multi-decadal scales.

  1. Comparison of Flow Characteristics Around Refractive and Right-angled Groins in Barotropic and Baroclinic Conditions

    Institute of Scientific and Technical Information of China (English)

    Omdehghiasi Hamed; Mojtahedi Alireza; Lotfollahi-Yaghin Mohammad Ali

    2015-01-01

    Groins are employed to prevent nearshore areas from erosion and to control the direction of flow. However, the groin structure and its associated flow characteristics are the main causes of local erosion. In this study, we investigate the flow patterns around refractive and right-angle groins. In particular, we analytically compare the flow characteristics around a refractive groin and study the degree of accuracy that can be achieved by using a right-angle groin of various projected lengths. To compare the flow characteristics, we replaced the right-angle groin with an approximation of a refractive groin. This replacement had the least effect on the maximum velocity of flow in the channel. Moreover, we investigated the distribution of the density variables of temperature and salinity, and their effects on the flow characteristics around the right-angle groin. A comparison of the flow analysis results in baroclinic and barotropic conditions reveals that the flow characteristic values are very similar for both the refractive and right-angle groins. The geometry of the groin, i.e., right-angle or refractive, has little effect on the maximum speed to relative average speed. Apart from the angular separation, the arm length of the groin in downstream refractive groins has less effect on other flow characteristics than do upstream refractive groins. We also correlated a number of non-dimensional variables with respect to various flow characteristics and groin geometry. These comparisons indicate that the correlation between the thalweg height and width of the channel and groin arm’s length to projection length have been approximated using linear and nonlinear formulas regardless of inner velocity in the subcritical flow.

  2. The radiative zone of the Sun and the tachocline: stability of baroclinic patterns of differential rotation

    Science.gov (United States)

    Caleo, Andrea; Balbus, Steven A.

    2016-04-01

    Barotropic rotation and radiative equilibrium are mutually incompatible in stars. The issue is often addressed by allowing for a meridional circulation, but this is not devoid of theoretical complications. Models of rotation in the Sun which maintain strict radiative equilibrium, making use of the observation that the Sun is not in a state of barotropic rotation, have recently been suggested. To investigate the dynamical behaviour of these solutions, we study the local stability of stratified, weakly magnetized, differentially rotating fluids to non-axisymmetric perturbations. Finite heat conductivity, kinematic viscosity, and resistivity are present. The evolution of local embedded perturbations is governed by a set of coupled, ordinary differential equations with time-dependent coefficients. Two baroclinic models of rotation for the upper radiative zone and tachocline are studied: (i) an interpolation based on helioseismology data, (ii) a theoretical solution directly compatible with radiative equilibrium. The growth of the local Goldreich-Schubert-Fricke instability appears to be suppressed, largely because of the viscosity. An extensive exploration of wavenumber space is carried out, with and without a magnetic field. Although we easily find classical local instabilities when they ought formally to be present, for the Sun the analysis reveals neither unstable solutions, nor even solutions featuring a large transient growth. We have not ruled out larger scale or non-linear instabilities, nor have we rigorously proven local stability. But rotational configurations in close agreement with observations, generally thought to be vulnerable to the classic local Goldreich-Schubert-Fricke instability, do appear to be locally stable under rather general circumstances.

  3. Trends and projections of Southern Hemisphere baroclinicity: the role of external forcing and impact on Australian rainfall

    Science.gov (United States)

    Frederiksen, Carsten S.; Frederiksen, Jorgen S.; Sisson, Janice M.; Osbrough, Stacey L.

    2016-07-01

    Changes in the characteristics of Southern Hemisphere (SH) storms, in all seasons, during the second half of the twentieth century, have been related to changes in the annual cycle of SH baroclinic instability. In particular, significant negative trends in baroclinic instability, as measured by the Phillips Criterion, have been found in the region of the climatological storm tracks; a zonal band of significant positive trends occur further poleward. Corresponding to this decrease/increase in baroclinic instability there is a decrease/increase in the growth rate of storm formation at these latitudes over this period, and in some cases a preference for storm formation further poleward than normal. Based on model output from a multi-model ensemble (MME) of coupled atmosphere-ocean general circulation models, it is shown that these trends are the result of external radiative forcing, including anthropogenic greenhouse gases, ozone, aerosols and land-use change. The MME is used in an analysis of variance method to separate the internal (natural) variability in the Phillips Criterion from influences associated with anomalous external radiative forcing. In all seasons, the leading externally forced mode has a significant trend and a loading pattern highly correlated with the pattern of trends in the Phillips Criterion. The covariance between the externally forced component of SH rainfall and the leading external mode strongly resembles the MME pattern of SH rainfall trends. A comparison between similar analyses of MME simulations using the second half of the twenty-first century of the Representative Concentration Pathways (RCP) RCP8.5 and RCP4.5 scenarios show that trends in the Phillips Criterion and rainfall are projected to continue and intensify under increasing anthropogenic greenhouse gas concentrations.

  4. Trends and projections of Southern Hemisphere baroclinicity: the role of external forcing and impact on Australian rainfall

    Science.gov (United States)

    Frederiksen, Carsten S.; Frederiksen, Jorgen S.; Sisson, Janice M.; Osbrough, Stacey L.

    2017-05-01

    Changes in the characteristics of Southern Hemisphere (SH) storms, in all seasons, during the second half of the twentieth century, have been related to changes in the annual cycle of SH baroclinic instability. In particular, significant negative trends in baroclinic instability, as measured by the Phillips Criterion, have been found in the region of the climatological storm tracks; a zonal band of significant positive trends occur further poleward. Corresponding to this decrease/increase in baroclinic instability there is a decrease/increase in the growth rate of storm formation at these latitudes over this period, and in some cases a preference for storm formation further poleward than normal. Based on model output from a multi-model ensemble (MME) of coupled atmosphere-ocean general circulation models, it is shown that these trends are the result of external radiative forcing, including anthropogenic greenhouse gases, ozone, aerosols and land-use change. The MME is used in an analysis of variance method to separate the internal (natural) variability in the Phillips Criterion from influences associated with anomalous external radiative forcing. In all seasons, the leading externally forced mode has a significant trend and a loading pattern highly correlated with the pattern of trends in the Phillips Criterion. The covariance between the externally forced component of SH rainfall and the leading external mode strongly resembles the MME pattern of SH rainfall trends. A comparison between similar analyses of MME simulations using the second half of the twenty-first century of the Representative Concentration Pathways (RCP) RCP8.5 and RCP4.5 scenarios show that trends in the Phillips Criterion and rainfall are projected to continue and intensify under increasing anthropogenic greenhouse gas concentrations.

  5. Recent advances on macro-scale and micro-scale dynamic interaction between high earth-rock dams and water%高土石坝宏细观坝水动力流固耦合理论研究进展

    Institute of Scientific and Technical Information of China (English)

    岑威钧; 孙辉; 陈亚南

    2013-01-01

    The dynamic interaction will happen among high earth-rock dams, reservoir and pore water under a strong earthquake. This paper introduces the main research history, research results and research trends of water-soil coupling system for earth-rock dams from the macro-scale and micro-scale aspects. On the macro-scale dynamic coupling system, the early dam-water interaction model, sophisticated analytical methods of reservoir water and FSI coordinate system description are summarized, and on the micro-scale dynamic coupling system, mainly from the early water-soil decoupled dynamic analysis method, and the water-soil coupling analysis system based on the Boit's theory and the water-soil mixture theory, ect. Combining the above two research aspects of soil-water coupling system, a macro-scale and micro-scale coupling system of reservoir-dam-pore water is proposed to study the dynamic behavior of high earth-rock dams comprehensively. Finally, the main problems on the macro-scale and micro-scale water-soil coupling theory and further research topics are put forward.%高土石坝遭遇强烈地震时会与坝面库水及坝内孔隙水发生动力流固耦合相互作用,分别从宏观坝水耦合系统和细观水土耦合系统两个角度对高土石坝坝水动力流固耦合理论的研究历史、主要研究成果和研究趋势进行了阐述评价。对宏观尺度的大坝与坝面库水流固耦合作用,主要从早期坝水相互作用模型、库水运动精细分析方法以及流固耦合系统坐标描述等方面做出评述;对细观尺度的坝内水土耦合作用,主要从早期解耦或拟耦合的水土动力分析方法、基于Boit动力固结理论的细观水土动力流固耦合,以及基于混合物理论的细观水土动力流固耦合等方面做出评述。综合两个尺度的流固耦合作用研究现状,建议对高土石坝建立水库土石坝孔隙水的宏细观整体动力流固耦合系统进行综合研究,并

  6. Impact of observed North Atlantic multidecadal variations to European summer climate: a linear baroclinic response to surface heating

    Science.gov (United States)

    Ghosh, Rohit; Müller, Wolfgang A.; Baehr, Johanna; Bader, Jürgen

    2017-06-01

    The observed prominent multidecadal variations in the central to eastern (C-E) European summer temperature are closely related to the Atlantic multidecadal variability (AMV). Using the Twentieth Century Reanalysis project version 2 data for the period of 1930-2012, we present a mechanism by which the multidecadal variations in the C-E European summer temperature are associated to a linear baroclinic atmospheric response to the AMV-related surface heat flux. Our results suggest that over the north-western Atlantic, the positive heat flux anomaly triggers a surface baroclinic pressure response to diabatic heating with a negative surface pressure anomaly to the east of the heat source. Further downstream, this response induces an east-west wave-like pressure anomaly. The east-west wave-like response in the sea level pressure structure, to which we refer as North-Atlantic-European East West (NEW) mode, is independent of the summer North Atlantic Oscillation and is the principal mode of variations during summer over the Euro-Atlantic region at multidecadal time scales. The NEW mode causes warming of the C-E European region by creating an atmospheric blocking-like situation. Our findings also suggest that this NEW mode is responsible for the multidecadal variations in precipitation over the British Isles and north-western Europe.

  7. The 10-12 November 2001 Balearic Superstorm: An Assessment of Baroclinic and Diabatic Contributions Through Pv Diagnosis

    Science.gov (United States)

    Romero, R.; Homar, V.; Ramis, C.; Alonso, S.

    From 10 to 12 November 2001 the western Mediterranean zone was affected by a hazardous cyclone. In the Balearic Islands the storm was particularly strong: wind gusts exceeded 140 km/h, heavy precipitation up to 400 mm in two days was recorded and sea waves up to 12 m reached the shoreline. Four casualties occurred, more than 100.000 trees were uprooted, many boats and coastal infrastructures were severely damaged and some crop fields were flooded. Surface and upper level weather maps suggest that the cyclone was consequence of an initial baroclinic development over north Africa and a further deepening over the western Mediterranean. Quasi- geostrophic diagnosis has been performed to study the baroclinic contribution to the cyclogenesis. A Potential Vorticity (PV) inversion technique has been applied to de- termine the role of three prominent PV positive anomalies over the region (associated with an upper level trough, a low level warm air intrusion over the Mediterranean from Africa and the latent heat release) to the cyclone intensity.

  8. An implicit wetting and drying approach for non-hydrostatic baroclinic flows in high aspect ratio domains

    Science.gov (United States)

    Candy, A. S.

    2017-04-01

    A new approach to modelling free surface flows is developed that enables, for the first time, 3D consistent non-hydrostatic baroclinic physics that wets and drys in the large aspect ratio spatial domains that characterise geophysical systems. This is key in the integration of physical models to permit seamless simulation in a single consistent arbitrarily unstructured multiscale and multi-physics dynamical model. A high order continuum representation is achieved through a general Galerkin finite element formulation that guarantees local and global mass conservation, and consistent tracer advection. A flexible spatial discretisation permits conforming domain bounds and a variable spatial resolution, whilst atypical use of fully implicit time integration ensures computational efficiency. Notably this brings the natural inclusion of non-hydrostatic baroclinic physics and a consideration of vertical inertia to flood modelling in the full 3D domain. This has application in improving modelling of inundation processes in geophysical domains, where dynamics proceeds over a large range of horizontal extents relative to vertical resolution, such as in the evolution of a tsunami, or in urban environments containing complex geometric structures at a range of scales.

  9. AN EXPERIMENTAL STUDY ON THREE-DIMENSIONAL STRUCTURE OF BAROCLINIC WAVY JET STREAM IN A ROTATING ANNULUS SUBJECT TO RADIAL TEMPERATURE GRADIENT

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Three-dimensional structure of baroclinic wavy jet was experimentally studied in rotating annulus subject to a negative radial temperature gradient.General features of wavy surface jet in the system were obtained.Based on the precise measurements of velocity distribution of the jet with LDV and the three-dimensional temperature field in the convective system, three-dimensional thermodynamic structures of jet were gained, and by using a correlation of three-dimensional disturbed temperature, the unstable mechanism of disturbed temperature of baroclinic fluid in a rotating system was further discussed.

  10. The wind and thermally driven circulation of the eastern Mediterranean Sea. Part II: the Baroclinic case

    Science.gov (United States)

    Malanotte-Rizzoli, Paola; Bergamasco, Andrea

    1991-04-01

    Compared with other interesting parts of the World Ocean, little is known of the eastern Mediterranean and major issues of the Mediterranean circulation are still unsolved. Among them, the most crucial one is: what is the dominant driving mechanism of the eastern Mediterranean general circulation: (1) the wind stress; (2) the thermohaline surface fluxes; (3) the inflow forcing at the Sicily Straits? What is the relative importance of these three forcing functions? Is it the same in the different sub-basins comprising the eastern Mediterranean? What modelling factors are important for the simulation of the seasonal cycle and is the general circulation overall dominated by the annual mean or seasonal signal? To answer the above questions we have carried out an extensive and thorough series of numerical experiments using a multilevel model of the circulation, suitable for coarse-resolution studies but endowed with active thermodynamics and allowing for realistic geometry (coastlines, islands, bottom relief). The model is used in a three-level version as the minimum one capable of simulating the vertical superposition of different water masses observed in the eastern Mediterranean. The climatological monthly averages of wind-stress, thermal and evaporative fluxes and inflow at Sicily are used to drive the model. In Part I of the present study it was shown that the seasonal cycle present in the wind-stress curl induces a strongly seasonal barotropic circulation comprising the entire eastern Mediterranean. This seasonal gyre reverses from being cyclonic in winter to anticyclonic in summer. The inclusion of baroclinicity, however, profoundly modifies the purely wind-driven, barotropic circulation, eliminating the strong seasonality and the winter-to-summer reversal. The first important result is that the general circulation pattern now consists of a succession of sub-basin-scale gyres, with a seasonal modulation emphasizing the cyclonic centres in winter and the

  11. Baroclinicity, Forcing Mechanism and Prediction of Chemical Propagation of San Diego Bay and Their Effects on Naval Applications

    Science.gov (United States)

    2005-06-01

    synthetically produced from carbon oxides and hydrogen. It has a faintly sweet pungent odor like that of ethyl alcohol. It has a flash point 12.222oC and...degradation rate is 0.1586 in both air and water. Contact with ammonia could cause skin and eye burns and inhalation some burning sensation , cough

  12. Synchronization in a coupled two-layer quasigeostrophic model of baroclinic instability – Part 1: Master-slave configuration

    Directory of Open Access Journals (Sweden)

    P. L. Read

    2009-08-01

    Full Text Available Synchronization is studied using a pair of diffusively-coupled, two-layer quasi-geostrophic systems each comprising a single baroclinic wave and a zonal flow. In particular, the coupling between the systems is in the well-known master-slave or one-way configuration. Nonlinear time series analysis, phase dynamics, and bifurcation diagrams are used to study the dynamics of the coupled system. Phase synchronization, imperfect synchronization (phase slips, or complete synchronization are found, depending upon the strength of coupling, when the systems are either in a periodic or a chaotic regime. The results of investigations when the dynamics of each system are in different regimes are also presented. These results also show evidence of phase synchronization and signs of chaos control.

  13. Nonlinear Phenomena in Complex Systems: From Nano to Macro Scale

    CERN Document Server

    Stanley, H

    2014-01-01

    Topics of complex system physics and their interdisciplinary applications to different problems in seismology, biology, economy, sociology,  energy and nanotechnology are covered in this new work from renowned experts in their fields.  In  particular, contributed papers contain original results on network science, earthquake dynamics, econophysics, sociophysics, nanoscience and biological physics. Most of the papers use interdisciplinary approaches based on statistical physics, quantum physics and other topics of complex system physics.  Papers on econophysics and sociophysics are focussed on societal aspects of physics such as, opinion dynamics, public debates and financial and economic stability. This work will be of interest to statistical physicists, economists, biologists, seismologists and all scientists working in interdisciplinary topics of complexity.

  14. A Cross-Scale Model for 3D Baroclinic Circulation in Estuary-Plume-Shelf Systems. 2. Application to the Columbia River

    Science.gov (United States)

    2005-01-01

    X ’ -Available online at www.sciencedirect.com SCIENCE DRC CONTINENTAL SHELFd RESEARCH ELSEVIER Continental Shelf Research 25 (2005) 935-972...06-2005 Journal Article ( refereed ) 4, TITLE AND SUBTITLE 5a. CONTRACT NUMBER A Qross-Scale Model for 3D Baroclinic Circulation in Estuary-Plume-Shelf...5510.40D ) Conference Proceedings ( ) Conference Proceedings Route Sheet No.7303/ ( refereed ) (not refereed ) Job Order No. 73-8404-04-5 End: (1) Two copies

  15. Baroclinic instability of a symmetric, rotating, stratified flow: a study of the nonlinear stabilisation mechanisms in the presence of viscosity

    Directory of Open Access Journals (Sweden)

    R. Mantovani

    2002-01-01

    Full Text Available This paper presents the analysis of symmetric circulations of a rotating baroclinic flow, forced by a steady thermal wind and dissipated by Laplacian friction. The analysis is performed with numerical time-integration. Symmetric flows, vertically bound by horizontal walls and subject to either periodic or vertical wall lateral boundary conditions, are investigated in the region of parameter-space where unstable small amplitude modes evolve into stable stationary nonlinear solutions. The distribution of solutions in parameter-space is analysed up to the threshold of chaotic behaviour and the physical nature of the nonlinear interaction operating on the finite amplitude unstable modes is investigated. In particular, analysis of time-dependent energy-conversions allows understanding of the physical mechanisms operating from the initial phase of linear instability to the finite amplitude stable state. Vertical shear of the basic flow is shown to play a direct role in injecting energy into symmetric flow since the stage of linear growth. Dissipation proves essential not only in limiting the energy of linearly unstable modes, but also in selecting their dominant space-scales in the finite amplitude stage.

  16. Drivers of barotropic and baroclinic exchange through an estuarine navigation channel in the Mississippi River Delta Plain

    Science.gov (United States)

    Snedden, Gregg

    2016-01-01

    Estuarine navigation channels have long been recognized as conduits for saltwater intrusion into coastal wetlands. Salt flux decomposition and time series measurements of velocity and salinity were used to examine salt flux components and drivers of baroclinic and barotropic exchange in the Houma Navigation Channel, an estuarine channel located in the Mississippi River delta plain that receives substantial freshwater inputs from the Mississippi-Atchafalaya River system at its inland extent. Two modes of vertical current structure were identified from the time series data. The first mode, accounting for 90% of the total flow field variability, strongly resembled a barotropic current structure and was coherent with alongshelf wind stress over the coastal Gulf of Mexico. The second mode was indicative of gravitational circulation and was linked to variability in tidal stirring and the horizontal salinity gradient along the channel’s length. Tidal oscillatory salt flux was more important than gravitational circulation in transporting salt upestuary, except over equatorial phases of the fortnightly tidal cycle during times when river inflows were minimal. During all tidal cycles sampled, the advective flux, driven by a combination of freshwater discharge and wind-driven changes in storage, was the dominant transport term, and net flux of salt was always out of the estuary. These findings indicate that although human-made channels can effectively facilitate inland intrusion of saline water, this intrusion can be minimized or even reversed when they are subject to significant freshwater inputs.

  17. General circulation driven by baroclinic forcing due to cloud layer heating: Significance of planetary rotation and polar eddy heat transport

    Science.gov (United States)

    Yamamoto, Masaru; Takahashi, Masaaki

    2016-04-01

    A high significance of planetary rotation and poleward eddy heat fluxes is determined for general circulation driven by baroclinic forcing due to cloud layer heating. In a high-resolution simplified Venus general circulation model, a planetary-scale mixed Rossby-gravity wave with meridional winds across the poles produces strong poleward heat flux and indirect circulation. This strong poleward heat transport induces downward momentum transport of indirect cells in the regions of weak high-latitude jets. It also reduces the meridional temperature gradient and vertical shear of the high-latitude jets in accordance with the thermal wind relation below the cloud layer. In contrast, strong equatorial superrotation and midlatitude jets form in the cloud layer in the absence of polar indirect cells in an experiment involving Titan's rotation. Both the strong midlatitude jet and meridional temperature gradient are maintained in the situation that eddy horizontal heat fluxes are weak. The presence or absence of strong poleward eddy heat flux is one of the important factors determining the slow or fast superrotation state in the cloud layer through the downward angular momentum transport and the thermal wind relation. For fast Earth rotation, a weak global-scale Hadley circulation of the low-density upper atmosphere maintains equatorial superrotation and midlatitude jets above the cloud layer, whereas multiple meridional circulations suppress the zonal wind speed below the cloud layer.

  18. THREE-DIMENSIONAL BAROCLINIC NUMERICAL SIMULATION OF THE SOUTH CHINA SEA CIRCULATION'S SEASONAL CHARACTERISTICS II. MIDDLE AND DEEP CIRCULATION

    Institute of Scientific and Technical Information of China (English)

    蔡树群; 甘子钧; 苏纪兰; 刘秦玉

    2002-01-01

    A three-dimensional baroclinic shelf sea model's numerical simulation of the South China Sea (SCS) middle and deep layer circulation structure showed that: 1. In the SCS middle and deep layer, a southward boundary current exists along the east shore of the Indo-China Peninsula all year long. A cyclonic eddy (gyre) is formed by the current in the above sea areas except in the middle layer in spring, when an anticyclonic eddy exists on the eastern side of the current. In the deep layer, a large-scale anticyclonic eddy often exists in the sea areas between the Zhongsha Islands and west shore of southern Luzon Island. 2. In the middle layer in summer and autumn, and in the deep layer in autumn and winter, there is an anticyclonic eddy (gyre) in the northeastern SCS, while in the middle layer in winter and spring, and in the deep layer in spring and summer, there is a cyclonic one. 3. In the middle layer, there is a weak northeastward current in the Nansha Trough in spring and summer, while in autumn and winter it evolves into an anticyclonic eddy (gyre), which then spreads westward to the whole western Nansha Islands sea areas.

  19. Drivers of Barotropic and Baroclinic Exchange through an Estuarine Navigation Channel in the Mississippi River Delta Plain

    Directory of Open Access Journals (Sweden)

    Gregg A. Snedden

    2016-04-01

    Full Text Available Estuarine navigation channels have long been recognized as conduits for saltwater intrusion into coastal wetlands. Salt flux decomposition and time series measurements of velocity and salinity were used to examine salt flux components and drivers of baroclinic and barotropic exchange in the Houma Navigation Channel, an estuarine channel located in the Mississippi River delta plain that receives substantial freshwater inputs from the Mississippi-Atchafalaya River system at its inland extent. Two modes of vertical current structure were identified from the time series data. The first mode, accounting for 90% of the total flow field variability, strongly resembled a barotropic current structure and was coherent with alongshelf wind stress over the coastal Gulf of Mexico. The second mode was indicative of gravitational circulation and was linked to variability in tidal stirring and the horizontal salinity gradient along the channel’s length. Tidal oscillatory salt flux was more important than gravitational circulation in transporting salt upestuary, except over equatorial phases of the fortnightly tidal cycle during times when river inflows were minimal. During all tidal cycles sampled, the advective flux, driven by a combination of freshwater discharge and wind-driven changes in storage, was the dominant transport term, and net flux of salt was always out of the estuary. These findings indicate that although human-made channels can effectively facilitate inland intrusion of saline water, this intrusion can be minimized or even reversed when they are subject to significant freshwater inputs.

  20. Prediction

    CERN Document Server

    Sornette, Didier

    2010-01-01

    This chapter first presents a rather personal view of some different aspects of predictability, going in crescendo from simple linear systems to high-dimensional nonlinear systems with stochastic forcing, which exhibit emergent properties such as phase transitions and regime shifts. Then, a detailed correspondence between the phenomenology of earthquakes, financial crashes and epileptic seizures is offered. The presented statistical evidence provides the substance of a general phase diagram for understanding the many facets of the spatio-temporal organization of these systems. A key insight is to organize the evidence and mechanisms in terms of two summarizing measures: (i) amplitude of disorder or heterogeneity in the system and (ii) level of coupling or interaction strength among the system's components. On the basis of the recently identified remarkable correspondence between earthquakes and seizures, we present detailed information on a class of stochastic point processes that has been found to be particu...

  1. Pressure Decimation and Interpolation (PDI) method for a baroclinic non-hydrostatic model

    Science.gov (United States)

    Shi, Jian; Shi, Fengyan; Kirby, James T.; Ma, Gangfeng; Wu, Guoxiang; Tong, Chaofeng; Zheng, Jinhai

    2015-12-01

    Non-hydrostatic models are computationally expensive in simulating density flows and mass transport problems due to the requirement of sufficient grid resolution to resolve density and flow structures. Numerical tests based on the Non-Hydrostatic Wave Model, NHWAVE (Ma et al., 2012), indicated that up to 70% of the total computational cost may be born by the pressure Poisson solver in cases with high grid resolution in both vertical and horizontal directions. However, recent studies using Poisson solver-based non-hydrostatic models have shown that an accurate prediction of wave dispersion does not require a large number of vertical layers if the dynamic pressure is properly discretized. In this study, we explore the possibility that the solution for the dynamic pressure field may, in general, be decimated to a resolution far coarser than that used in representing velocities and other transported quantities, without sacrificing accuracy of solutions. Following van Reeuwijk (2002), we determine the dynamic pressure field by solving the Poisson equation on a coarser grid and then interpolate the pressure field onto a finer grid used for solving for the remaining dynamic variables. With the Pressure Decimation and Interpolation (PDI) method, computational efficiency is greatly improved. We use three test cases to demonstrate the model's accuracy and efficiency in modeling density flows.

  2. Coherent structures in a baroclinic atmosphere. IV - A comparison between theory and data

    Science.gov (United States)

    Malanotte-Rizzoli, Paola; Hancock, Paul J.

    1987-01-01

    This paper presents the results of a data analysis, on an extensive series of Atlantic blocks, for the composites of both the positive and the negative anomaly cases and for the winter climatology, using the composite approach of Dole (1982, 1986). The results are compared with predictions of the theory formulated by Malguzzi and Malanotte-Rizzoli (1984, 1985) and Malanotte-Rizzoli and Malguzzi (1987) to model the blocking events. The results of the analyses indicate that the composite of the positive anomaly cases shows a strong northern barrier centered in the latitude band 62-72 deg N, in agreement with the northern confinement of the block. The northern, positive wall is not present in the climatology; its presence and significance are doubtful and debatable for the negative anomaly composite. For the individual positive cases for which a smooth and zonal upstream wind could be defined, the V-function shows the appearance of both a northern and southern wall below the tropopause.

  3. Maintenance of Baroclinicity in the Atlantic Storm Track and its Relation to the Sea Surface Temperature Gradient along the Gulf Stream

    Science.gov (United States)

    Spengler, Thomas; Papritz, Lukas; Dahl-Eriksen, Ståle

    2016-04-01

    The maintenance of baroclinicity along mid- and high-latitude storm tracks is a matter of ongoing debate. We devise a diagnostic based on the tendency equation for the slope of isentropic surfaces - a measure of the baroclinicity. The tendency comprises contributions from dynamic processes, latent heat release, radiation and subgrid-scale turbulence, which incorporates the effect of sensible heat fluxes. We present a climatology (for winter 2009 and 2010) of these tendencies over the North Atlantic and discuss the relevance of the SST gradient associated with the Gulf Stream. We find that adiabatic tilting flattens the isentropic surfaces, reflecting the action of growing baroclinic cyclones. This tendency is balanced climatologically by the generation of isentropic slope by diabatic processes. In the lower troposphere, the most intense diabatic increase of slope is found along the oceanic frontal zone associated with the Gulf Stream and at higher latitudes in the Labrador Sea, the Nordic Seas and the Barents Sea. Latent heat release and sensible heat fluxes both contribute substantially in these regions. A quantitative analysis of cold-air outbreaks emphasizes their important role in restoring the slope in the lower troposphere over the Gulf Stream region and off the sea-ice edge at high latitudes. We also present composites of strong events of slope tendency and latent heating as well as surface fluxes, pinpointing the relative contribution of the cold or warm sector of a cyclone to the slope tendency in the Gulf Stream region. In the upper troposphere, latent heat release due to cloud microphysical processes is the dominant mechanism maintaining the slope.

  4. Rotational Baroclinic Adjustment

    DEFF Research Database (Denmark)

    Holtegård Nielsen, Steen Morten

    to produce coastal currents flowing cyclonically through the Kattegat.Off the headland Skagen, the lightvessel observations together with earlier studies suggest that strong wind-driven currents are responsible for the location of the Kattegat/Skagerrak frontin this area.Observations from the interior...

  5. Rotational Baroclinic Adjustment

    DEFF Research Database (Denmark)

    Holtegård Nielsen, Steen Morten

    In stratified waters like those around Denmark there is a close correlation between the biology of the water masses and their structure and currents; this is known as dynamic biologicaloceanography. The currents are particularly strong near the fronts, which can be seen in several places throughout...... the reciprocal of the socalled Coriolis parameter, and the length scale, which is known as the Rossby radius. Also, because of their limited width currents influenced by rotation are quite persistent. The flow which results from the introduction of a surface level discontinuity across a wide channel is discussed...... of the numerical model a mechanism for the generation of along-frontal instabilities and eddies is suggested. Also, the effect of an irregular bathymetry is studied.Together with observations of wind and water levels some of the oceanographical observations from the old lightvessels are used to study...

  6. The application study on the multi-scales integrated prediction method to fractured reservoir description

    Institute of Scientific and Technical Information of China (English)

    Chen Shuang-Quan; Zeng Lian-Bo; Huang Ping; Sun Shao-Han; Zhang Wan-Lu; Li Xiang-Yang

    2016-01-01

    In this paper, we implement three scales of fracture integrated prediction study by classifying it to macro- (> 1/4λ), meso- (> 1/100λ and < 1/4λ) and micro- (< 1/100λ) scales. Based on the multi-scales rock physics modelling technique, the seismic azimuthal anisotropy characteristic is analyzed for distinguishing the fractures of meso-scale. Furthermore, by integrating geological core fracture description, image well-logging fracture interpretation, seismic attributes macro-scale fracture prediction and core slice micro-scale fracture characterization, an comprehensive multi-scale fracture prediction methodology and technique workfl ow are proposed by using geology, well-logging and seismic multi-attributes. Firstly, utilizing the geology core slice observation (Fractures description) and image well-logging data interpretation results, the main governing factors of fracture development are obtained, and then the control factors of the development of regional macro-scale fractures are carried out via modelling of the tectonic stress field. For the meso-scale fracture description, the poststack geometric attributes are used to describe the macro-scale fracture as well, the prestack attenuation seismic attribute is used to predict the meso-scale fracture. Finally, by combining lithological statistic inversion with superposed results of faults, the relationship of the meso-scale fractures, lithology and faults can be reasonably interpreted and the cause of meso-scale fractures can be verified. The micro-scale fracture description is mainly implemented by using the electron microscope scanning of cores. Therefore, the development of fractures in reservoirs is assessed by valuating three classes of fracture prediction results. An integrated fracture prediction application to a realfi eld in Sichuan basin, where limestone reservoir fractures developed, is implemented. The application results in the study area indicates that the proposed multi-scales integrated

  7. Chondrocyte Deformations as a Function of Tibiofemoral Joint Loading Predicted by a Generalized High-Throughput Pipeline of Multi-Scale Simulations

    Science.gov (United States)

    Sibole, Scott C.; Erdemir, Ahmet

    2012-01-01

    Cells of the musculoskeletal system are known to respond to mechanical loading and chondrocytes within the cartilage are not an exception. However, understanding how joint level loads relate to cell level deformations, e.g. in the cartilage, is not a straightforward task. In this study, a multi-scale analysis pipeline was implemented to post-process the results of a macro-scale finite element (FE) tibiofemoral joint model to provide joint mechanics based displacement boundary conditions to micro-scale cellular FE models of the cartilage, for the purpose of characterizing chondrocyte deformations in relation to tibiofemoral joint loading. It was possible to identify the load distribution within the knee among its tissue structures and ultimately within the cartilage among its extracellular matrix, pericellular environment and resident chondrocytes. Various cellular deformation metrics (aspect ratio change, volumetric strain, cellular effective strain and maximum shear strain) were calculated. To illustrate further utility of this multi-scale modeling pipeline, two micro-scale cartilage constructs were considered: an idealized single cell at the centroid of a 100×100×100 μm block commonly used in past research studies, and an anatomically based (11 cell model of the same volume) representation of the middle zone of tibiofemoral cartilage. In both cases, chondrocytes experienced amplified deformations compared to those at the macro-scale, predicted by simulating one body weight compressive loading on the tibiofemoral joint. In the 11 cell case, all cells experienced less deformation than the single cell case, and also exhibited a larger variance in deformation compared to other cells residing in the same block. The coupling method proved to be highly scalable due to micro-scale model independence that allowed for exploitation of distributed memory computing architecture. The method’s generalized nature also allows for substitution of any macro-scale and/or micro

  8. Chondrocyte deformations as a function of tibiofemoral joint loading predicted by a generalized high-throughput pipeline of multi-scale simulations.

    Directory of Open Access Journals (Sweden)

    Scott C Sibole

    Full Text Available Cells of the musculoskeletal system are known to respond to mechanical loading and chondrocytes within the cartilage are not an exception. However, understanding how joint level loads relate to cell level deformations, e.g. in the cartilage, is not a straightforward task. In this study, a multi-scale analysis pipeline was implemented to post-process the results of a macro-scale finite element (FE tibiofemoral joint model to provide joint mechanics based displacement boundary conditions to micro-scale cellular FE models of the cartilage, for the purpose of characterizing chondrocyte deformations in relation to tibiofemoral joint loading. It was possible to identify the load distribution within the knee among its tissue structures and ultimately within the cartilage among its extracellular matrix, pericellular environment and resident chondrocytes. Various cellular deformation metrics (aspect ratio change, volumetric strain, cellular effective strain and maximum shear strain were calculated. To illustrate further utility of this multi-scale modeling pipeline, two micro-scale cartilage constructs were considered: an idealized single cell at the centroid of a 100×100×100 μm block commonly used in past research studies, and an anatomically based (11 cell model of the same volume representation of the middle zone of tibiofemoral cartilage. In both cases, chondrocytes experienced amplified deformations compared to those at the macro-scale, predicted by simulating one body weight compressive loading on the tibiofemoral joint. In the 11 cell case, all cells experienced less deformation than the single cell case, and also exhibited a larger variance in deformation compared to other cells residing in the same block. The coupling method proved to be highly scalable due to micro-scale model independence that allowed for exploitation of distributed memory computing architecture. The method's generalized nature also allows for substitution of any macro-scale

  9. From Microstructures to Predict Properties of Materials

    Science.gov (United States)

    Wang, Ke-Gang

    2010-03-01

    Understanding the precise and fundamental manner in which materials structures (nanostructures or microstructures) and their evolution influences properties and service lifetimes of advanced materials profoundly impacts material design and today materials design plays an increasingly important rôle in many engineering applications. Linking structures to properties and predicting properties of materials is fundamental step for materials design. First, a framework of applications of multiscale modeling to property prediction of advanced materials will be briefly presented. As an example, a methodology will be shown to link micro-scale to the continuum scale, integrating microstructure modeling with the large Thermo-Calc^ database. This paradigm was successfully applied to the case of Fe-12Ni-6Mn maraging steel. Next, methodology for integrating first-principle calculation into simulations of microstructure evolution will be reviewed. Our methods are sufficiently reliable to permit control and fabrication of quantum-dots structures, nanocrystals, and particle-reinforced nanocomposites, as well as assist in the predictive behavior of macro-scale colloids, aerosols, and other soft matter systems.

  10. The effect of unsteady and baroclinic forcing on predicted wind profiles in Large Eddy Simulations: Two case studies of the daytime atmospheric boundary layer

    DEFF Research Database (Denmark)

    Pedersen, Jesper Grønnegaard; Kelly, Mark C.; Gryning, Sven-Erik;

    2013-01-01

    Due to its fine-resolution requirement and subsequent computational demand, Large Eddy Simulation of the atmospheric boundary layer is limited in most cases to computational domains extending only a few kilometers in both the vertical and horizontal directions. Variations in the flow...... and in relevant atmospheric fields (e.g. temperature) that occur at larger scales must be imposed through boundary conditions or as external forcing. In this work we study the influence of such variations on the wind profile in Large Eddy Simulations of daytime atmospheric boundary layers, by comparing......, LIDAR measurements of the wind speed up to heights between 900 and 1600 m and tower-based measurements up to 100 and 250 m are used to evaluate the performance of the variably-driven Large Eddy Simulations. We find in both case studies that including height- and time-variations in the applied pressure...

  11. Probabilistic Fatigue Life Prediction of Bridge Cables Based on Multiscaling and Mesoscopic Fracture Mechanics

    Directory of Open Access Journals (Sweden)

    Zhongxiang Liu

    2016-04-01

    Full Text Available Fatigue fracture of bridge stay-cables is usually a multiscale process as the crack grows from micro-scale to macro-scale. Such a process, however, is highly uncertain. In order to make a rational prediction of the residual life of bridge cables, a probabilistic fatigue approach is proposed, based on a comprehensive vehicle load model, finite element analysis and multiscaling and mesoscopic fracture mechanics. Uncertainties in both material properties and external loads are considered. The proposed method is demonstrated through the fatigue life prediction of cables of the Runyang Cable-Stayed Bridge in China, and it is found that cables along the bridge spans may have significantly different fatigue lives, and due to the variability, some of them may have shorter lives than those as expected from the design.

  12. Calculating the annual cycle of the vertical eddy viscosity in the North Sea with a three-dimensional baroclinic shelf sea circulation model

    Science.gov (United States)

    Pohlmann, Thomas

    1996-02-01

    The vertical eddy viscosity ( Av) is estimated using a three-dimensional baroclinic shelf sea model that treats the temperature as a prognostic quantity. Av is calculated by means of a turbulent closure approach proposed by Kochergin [(1987) Three-dimensional coastal ocean models, American Geophysical Union, pp. 201-208] which is closely related to a Mellor and Yamada [(1974) Journal of Atmospheric Science, 31, pp. 1791-1806] level-2-model that has been used very successfully in a large number of applications. The annual cycle of the vertical eddy viscosity is discussed by looking at horizontal and vertical A v-distributions for the year 1988. These examples show that the vertical eddy viscosity is subject to a pronounced annual cycle which can be related to heating and cooling processes as well as to mixing induced by wind and bottom friction. A comparison of these results with A v-distributions calculated for the year 1987 additionally demonstrates a strong inter-annual variability.

  13. Dynamics of stellar wind in a Roche potential: implications for (i) outflows & periodicities relevant to astronomical masers, and (ii) generation of baroclinicity

    CERN Document Server

    Singh, Nishant K

    2015-01-01

    We study the dynamics of stellar wind from one of the bodies in the binary system, where the other body interacts only gravitationally. We focus on following three issues: (i) we explore the origin of observed periodic variations in maser intensity; (ii) we address the nature of bipolar molecular outflows; and (iii) we show generation of baroclinicity in the same model setup. From direct numerical simulations and further numerical modelling, we find that the maser intensity along a given line of sight varies periodically due to periodic modulation of material density. This modulation period is of the order of the binary period. Another feature of this model is that the velocity structure of the flow remains unchanged with time in late stages of wind evolution. Therefore the location of the masing spot along the chosen sightline stays at the same spatial location, thus naturally explaining the observational fact. This also gives an appearance of bipolar nature in the standard position-velocity diagram, as has ...

  14. An assessment of the Brazil Current baroclinic structure and variability near 22° S in Distinct Ocean Forecasting and Analysis Systems

    Science.gov (United States)

    Lima, Mateus O.; Cirano, Mauro; Mata, Mauricio M.; Goes, Marlos; Goni, Gustavo; Baringer, Molly

    2016-07-01

    The Brazil Current (BC) is the Western Boundary Current of the South Atlantic subtropical gyre, the dominant dynamic feature in the South Atlantic Ocean. The importance of this current lies in that it is the main conduit of subtropical waters to higher latitudes in the South Atlantic Ocean. This study assesses the structure and variability of the BC across the nominal latitude of 22° S using data from the high-density eXpendable BathyThermograph (XBT) AX97 transect and from three numerical ocean models with data assimilation. This XBT transect was implemented in 2004 and represents one of the longer-term monitoring systems of the BC in existence. The goal of this work is to enhance the understanding of the temporal and spatial variability of the ocean dynamics in the southwestern South Atlantic Ocean by using a suite of hydrographic observations and numerical model outputs. In the present work, 37 XBT transect realizations using data collected between 2004 and 2012 are used. Daily outputs covering the same time period are evaluated from Hybrid Coordinate Ocean Model with the Navy Coupled Ocean Data Assimilation (HYCOM-NCODA) with a 1/12° horizontal resolution, and GLORYS2V3 and FOAM, both with a 1/4° horizontal resolution. These Ocean Forecasting and Analysis Systems (OFAS) are able to capture the mean observed features in the 22° S region, showing a BC core confined to the west of 39° W and an Intermediate Western Boundary Current between the depths of 200 and 800 m. However, the OFAS tend to overestimate the mean BC baroclinic volume transport across the AX97 reference transect and underestimate its variability. The OFAS show that the coastal region between the coastline and the western edge of the AX97 transect plays an important role in the mean BC total transport, contributing to up to 23 % of its value, and further that this transport is not sampled by the XBT observations with its current sampling strategy. In order to understand the variability of the

  15. Baroclinic stabilization effect of the Atlantic-Arctic water exchange simulated by the eddy-permitting ocean model and global atmosphere-ocean model

    Science.gov (United States)

    Moshonkin, Sergey; Bagno, Alexey; Gritsun, Andrey; Gusev, Anatoly

    2017-04-01

    Numerical experiments were performed with the global atmosphere-ocean model INMCM5 (for version of the international project CMIP6, resolution for atmosphere is 2°x1.5°, 21 level) and with the three-dimensional, free surface, sigma coordinate eddy-permitting ocean circulation model for Atlantic (from 30°S) - Arctic and Bering sea domain (0.25 degrees resolution, Institute of Numerical Mathematics Ocean Model or INMOM). Spatial resolution of the INMCM5 oceanic component is 0.5°x0.25°. Both models have 40 s-levels in ocean. Previously, the simulations were carried out for INMCM5 to generate climatic system stable state. Then model was run for 180 years. In the experiment with INMOM, CORE-II data for 1948-2009 were used. As the goal for comparing results of two these numerical models, we selected evolution of the density and velocity anomalies in the 0-300m active ocean layer near Fram Strait in the Greenland Sea, where oceanic cyclonic circulation influences Atlantic-Arctic water exchange. Anomalies were count without climatic seasonal cycle for time scales smaller than 30 years. We use Singular Value Decomposition analysis (SVD) for density-velocity anomalies with time lag from minus one to six months. Both models perform identical stable physical result. They reveal that changes of heat and salt transports by West Spitsbergen and East Greenland currents, caused by atmospheric forcing, produce the baroclinic modes of velocity anomalies in 0-300m layer, thereby stabilizing ocean response on the atmospheric forcing, which stimulates keeping water exchange between the North Atlantic and Arctic Ocean at the certain climatological level. The first SVD-mode of density-velocity anomalies is responsible for the cyclonic circulation variability. The second and third SVD-modes stabilize existing ocean circulation by the anticyclonic vorticity generation. The second and third SVD-modes give 35% of the input to the total dispersion of density anomalies and 16-18% of the

  16. Sensitivity analysis with regard to variations of physical forcing including two possible future hydrographic regimes for the Oeregrundsgrepen. A follow-up baroclinic 3D-model study

    Energy Technology Data Exchange (ETDEWEB)

    Engqvist, A. [A and I Engqvist Konsult HB, Vaxholm (Sweden); Andrejev, O. [Finnish Inst. of Marine Research, Helsinki (Finland)

    2000-02-15

    A sensitivity analysis with regard to variations of physical forcing has been performed using a 3D baroclinic model of the Oeregrundsgrepen area for a whole-year period with data pertaining to 1992. The results of these variations are compared to a nominal run with unaltered physical forcing. This nominal simulation is based on the experience gained in an earlier whole-year modelling of the same area; the difference is mainly that the present nominal simulation is run with identical parameters for the whole year. From a computational economy point of view it has been necessary to vary the time step between the month-long simulation periods. For all simulations with varied forcing, the same time step as for the nominal run has been used. The analysis also comprises the water turnover of a hypsographically defined subsection, the Bio Model area, located above the SFR depository. The external forcing factors that have been varied are the following (with their found relative impact on the volume average of the retention time of the Bio Model area over one year given within parentheses): atmospheric temperature increased/reduced by 2.5 deg C (-0.1% resp. +0.6%), local freshwater discharge rate doubled/halved (-1.6% resp. +0.01%), salinity range at the border increased/reduced a factor 2 (-0.84% resp. 0.00%), wind speed forcing reduced 10% (+8.6%). The results of these simulations, at least the yearly averages, permit a reasonably direct physical explanation, while the detailed dynamics is for natural reasons more intricate. Two additional full-year simulations of possible future hydrographic regimes have also been performed. The first mimics a hypothetical situation with permanent ice cover, which increases the average retention time 87%. The second regime entails the future hypsography with its anticipated shoreline displacement by an 11 m land-rise in the year 4000 AD, which also considerably increases the average retention times for the two remaining layers of the

  17. Separation of bacterial spores from flowing water in macro-scale cavities by ultrasonic standing waves

    CERN Document Server

    Lipkens, B; Costolo, M; Stevens, A; Rietman, Edward

    2010-01-01

    The separation of micron-sized bacterial spores (Bacillus cereus) from a steady flow of water through the use of ultrasonic standing waves is demonstrated. An ultrasonic resonator with cross-section of 0.0254 m x 0.0254 m has been designed with a flow inlet and outlet for a water stream that ensures laminar flow conditions into and out of the resonator section of the flow tube. A 0.01905-m diameter PZT-4, nominal 2-MHz transducer is used to generate ultrasonic standing waves in the resonator. The acoustic resonator is 0.0356 m from transducer face to the opposite reflector wall with the acoustic field in a direction orthogonal to the water flow direction. At fixed frequency excitation, spores are concentrated at the stable locations of the acoustic radiation force and trapped in the resonator region. The effect of the transducer voltage and frequency on the efficiency of spore capture in the resonator has been investigated. Successful separation of B. cereus spores from water with typical volume flow rates of...

  18. The divining root: moisture-driven responses of roots at the micro- and macro-scale.

    Science.gov (United States)

    Robbins, Neil E; Dinneny, José R

    2015-04-01

    Water is fundamental to plant life, but the mechanisms by which plant roots sense and respond to variations in water availability in the soil are poorly understood. Many studies of responses to water deficit have focused on large-scale effects of this stress, but have overlooked responses at the sub-organ or cellular level that give rise to emergent whole-plant phenotypes. We have recently discovered hydropatterning, an adaptive environmental response in which roots position new lateral branches according to the spatial distribution of available water across the circumferential axis. This discovery illustrates that roots are capable of sensing and responding to water availability at spatial scales far lower than those normally studied for such processes. This review will explore how roots respond to water availability with an emphasis on what is currently known at different spatial scales. Beginning at the micro-scale, there is a discussion of water physiology at the cellular level and proposed sensory mechanisms cells use to detect osmotic status. The implications of these principles are then explored in the context of cell and organ growth under non-stress and water-deficit conditions. Following this, several adaptive responses employed by roots to tailor their functionality to the local moisture environment are discussed, including patterning of lateral root development and generation of hydraulic barriers to limit water loss. We speculate that these micro-scale responses are necessary for optimal functionality of the root system in a heterogeneous moisture environment, allowing for efficient water uptake with minimal water loss during periods of drought. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  19. Macro-scale pseudo-particle modeling for particle-fluid systems

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Pseudo-particle modeling (PPM) is a particle method (PM) proposed in 1996. Though it is effective for the simulation of microscopic particle-fluid systems, its application to practical systems is still limited by computational cost.In this note, we speed up the computation by using a combination of weighted averaging with finite difference techniques to upgrade the particle interactions to a fluid element level, which conforms to the Navier-Stokes equation. The approach, abbreviated to MaPPM, is then applied to the problem of one-dimensional Poiseuille flow with a quantitative comparison to the results of another related PM smoothed particle hydrodynamics (SPH), where the accuracy and efficiency of MaPPM is found to be much better than that of SPH. Flows around a cylinder and multiple freely moving particles are also simulated with the new model, resulting in reasonable flow pattern and drag coefficient. The convergence and robustness of the algorithm prove promising.``

  20. Population vulnerability to biannual cholera outbreaks and associated macro-scale drivers in the Bengal Delta.

    Science.gov (United States)

    Akanda, Ali Shafqat; Jutla, Antarpreet S; Gute, David M; Sack, R Bradley; Alam, Munirul; Huq, Anwar; Colwell, Rita R; Islam, Shafiqul

    2013-11-01

    The highly populated floodplains of the Bengal Delta have a long history of endemic and epidemic cholera outbreaks, both coastal and inland. Previous studies have not addressed the spatio-temporal dynamics of population vulnerability related to the influence of underlying large-scale processes. We analyzed spatial and temporal variability of cholera incidence across six surveillance sites in the Bengal Delta and their association with regional hydroclimatic and environmental drivers. More specifically, we use salinity and flood inundation modeling across the vulnerable districts of Bangladesh to test earlier proposed hypotheses on the role of these environmental variables. Our results show strong influence of seasonal and interannual variability in estuarine salinity on spring outbreaks and inland flooding on fall outbreaks. A large segment of the population in the Bengal Delta floodplains remain vulnerable to these biannual cholera transmission mechanisms that provide ecologic and environmental conditions for outbreaks over large geographic regions.

  1. Silicon crystal growth from the melt: Analysis from atomic and macro scales

    Energy Technology Data Exchange (ETDEWEB)

    Kakimoto, K.; Liu, L.; Kitashima, T.; Murakawa, A.; Hashimoto, Y. [Research Institute for Applied Mechanics, Kyushu University, 6-1, Kasuga-Koen, Kasuga 816-8580 (Japan)

    2005-04-01

    The effect of impurity concentration on thermal conductivity of natural and isotope silicon by using equilibrium molecular dynamics simulation is investigated. It was found that the concentrations of the impurities such as boron, phosphor and arsene play an important role in the propagation of phonons in silicon crystals. It was also clarified that a mass difference of impurities and host crystals results in degradation of thermal conductivity of silicon. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Data driven clustering of rain events: microphysics information derived from macro scale observations

    OpenAIRE

    Dilmi, Mohamed Djallel; Mallet, Cécile; Barthes, Laurent; Chazottes, Aymeric

    2016-01-01

    The study of rain time series records is mainly carried out using rainfall rate or rain accumulation parameters estimated on a fixed duration (typically 1 min, 1 hour or 1 day). In this paper we used the concept of rain event. Among the numerous existing variables dedicated to the characterisation of rain events, the first part of this paper aims to obtain a parsimonious characterisation of these events using a minimal set of variables. In this context an algorithm based on Genetic Algorithm ...

  3. Predator-prey interactions as macro-scale drivers of species diversity in mammals

    DEFF Research Database (Denmark)

    Sandom, Christopher James; Sandel, Brody Steven; Dalby, Lars

    -down). We gathered distributional range, mass and diet data for 4,091 terrestrial mammal species, excluding bats. Species richness maps were created for predators and prey and structural equation modelling was used to test the three hypotheses at continental and global scales. We also explored...

  4. Characterizing pesticide sorption and degradation in macro scale biopurification systems using column displacement experiments.

    Science.gov (United States)

    De Wilde, Tineke; Spanoghe, Pieter; Mertens, Jan; Sniegowksi, Kristel; Ryckeboer, Jaak; Jaeken, Peter; Springael, Dirk

    2009-04-01

    The efficiency of biopurification systems to treat pesticide-contaminated water was previously studied in microcosms. To validate the obtained results, macrocosm systems were set-up. Four pesticides (linuron, isoproturon, bentazone, and metalaxyl) were continuously applied to ten different organic substrate mixes. Retention of the pesticides was similar and in some cases slightly lower in the macrocosms compared to the microcosms. Differences in retention between the different mixes were however minimal. Moreover, the classification of the retention strength of the pesticides was identical to that observed in microcosms: linuron>isoproturon>metalaxyl>bentazone. Monod kinetics were used to describe delayed degradation, which occurred for isoproturon, metalaxyl and bentazone. No breakthrough of linuron was observed, thus, this pesticide was appointed as the most retained and/or degraded pesticide, followed by isoproturon, metalaxyl and bentazone. Finally, most of the matrix mixes efficient in degrading or retaining pesticides were mixes containing dried cow manure.

  5. Characterizing pesticide sorption and degradation in macro scale biopurification systems using column displacement experiments

    Energy Technology Data Exchange (ETDEWEB)

    Wilde, Tineke de [Laboratory of Crop Protection Chemistry, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent (Belgium)], E-mail: Tineke.DeWilde@UGent.be; Spanoghe, Pieter [Laboratory of Crop Protection Chemistry, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent (Belgium); Mertens, Jan; Sniegowksi, Kristel; Ryckeboer, Jaak [Division of Soil and Water Management, Faculty of Bioscience Engineering, K.U. Leuven, Kasteelpark Arenberg 20, B-3001 Heverlee (Belgium); Jaeken, Peter [PCF-Royal Research Station of Gorsem, De Brede Akker 13, 3800 Sint-Truiden (Belgium); Springael, Dirk [Division of Soil and Water Management, Faculty of Bioscience Engineering, K.U. Leuven, Kasteelpark Arenberg 20, B-3001 Heverlee (Belgium)

    2009-04-15

    The efficiency of biopurification systems to treat pesticide-contaminated water was previously studied in microcosms. To validate the obtained results, macrocosm systems were set-up. Four pesticides (linuron, isoproturon, bentazone, and metalaxyl) were continuously applied to ten different organic substrate mixes. Retention of the pesticides was similar and in some cases slightly lower in the macrocosms compared to the microcosms. Differences in retention between the different mixes were however minimal. Moreover, the classification of the retention strength of the pesticides was identical to that observed in microcosms: linuron > isoproturon > metalaxyl > bentazone. Monod kinetics were used to describe delayed degradation, which occurred for isoproturon, metalaxyl and bentazone. No breakthrough of linuron was observed, thus, this pesticide was appointed as the most retained and/or degraded pesticide, followed by isoproturon, metalaxyl and bentazone. Finally, most of the matrix mixes efficient in degrading or retaining pesticides were mixes containing dried cow manure. - Transport of pesticides in macrocosm containing organic substrates.

  6. Micro- and macro-scale self-organization in a dissipative plasma

    Energy Technology Data Exchange (ETDEWEB)

    Skoric, M.M.; Sato, T. [National Inst. for Fusion Science, Toki, Gifu (Japan); Maluckov, A.; Jovanovic, M.S.

    1998-10-01

    We study a nonlinear three-wave interaction in an open dissipative model of stimulated Raman backscattering in a plasma. A hybrid kinetic-fluid scheme is proposed to include anomalous kinetic dissipation due to electron trapping and plasma wave breaking. We simulate a finite plasma with open boundaries and vary a transport parameter to examine a route to spatio-temporal complexity. An interplay between self-organization at micro (kinetic) and macro (wave/fluid) scales is revealed through quasi-periodic and intermittent evolution of dynamical variables, dissipative structures and related entropy rates. An evidence that entropy rate extrema correspond to structural transitions is found. (author)

  7. Negative-resistance voltage-current characteristics of superconductor contact junctions for macro-scale applications

    CERN Document Server

    Takayasu, M; Minervini, J V; 10.1109/TASC.2003.812854

    2003-01-01

    Voltage-current characteristics of mechanical pressure contact junctions between superconducting wires are investigated using a voltage-driving method. It is found that the switching regions at low voltages result from negative resistance of the contact junction. The current transport of the contact junctions is discussed from the perspective of two existing models: the multiple Andreev reflections at the two SN interfaces of a SNS (Superconductor/Normal metal /Superconductor) junction and the inhomogeneous multiple Josephson weak-link array. (13 refs).

  8. Turbulent velocity and concentration measurements in a macro-scale multi-inlet vortex nanoprecipitation reactor

    Science.gov (United States)

    Liu, Zhenping; Fox, Rodney; Hill, James; Olsen, Michael

    2013-11-01

    Flash Nanoprecipitation (FNP) is a technique to produce monodisperse functional nanoparticles. Microscale multi-inlet vortex reactors (MIVR) have been effectively applied to FNP due to their ability to provide rapid mixing and flexibility of inlet flow conditions. A scaled-up MIVR could potentially generate large quantities of functional nanoparticles, giving FNP wider applicability in industry. In the presented research, the turbulent velocity field inside a scaled-up, macroscale MIVR is measured by particle image velocimetry (PIV). Within the reactor, velocity is measured using both two-dimensional and stereoscopic PIV at two Reynolds numbers (3500 and 8750) based on the flow at each inlet. Data have been collected at numerous locations in the inlet channels, the reaction chamber, and the reactor outlet. Mean velocity and Reynolds stresses have been obtained based on 5000 instantaneous velocity realizations at each measurement location. The turbulent mixing process has also been investigated with passive scalar planar laser-induced fluorescence and simultaneous PIV/PLIF. Velocity and concentration results are compared to results from previous experiments in a microscale MIVR. Scaled profiles of turbulent quantities are similar to those previously found in the microscale MIVR.

  9. Experimental study of erosion by suffusion at the micro-macro scale

    Science.gov (United States)

    Nguyen, Cong Doan; Benahmed, Nadia; Philippe, Pierre; Diaz Gonzalez, Elizabeth Victoria

    2017-06-01

    Internal erosion is a complex phenomenon which represents one of the main sources of risk to the safety of earth hydraulic structures such as embankment dams, dikes and levees. Its occurrence may cause instability and failure of these structures with consequences that can be dramatic. Erosion by suffusion corresponds to the process of detachment and transport, under the action of hydraulic flow, of the finest soil particles within the porous media formed mainly of large grains. Its occurrence usually causes change of the initial microstructure and hence a change in the physical, hydraulic and mechanical characteristics of the soil. In this study, we present first an experimental characterization of the erosion mechanism during its occurrence within a granular soil. Particular emphasis was put on the role of hydraulic conditions in triggering of fines migration. Thereafter, we present a preliminary microstructural characterization of the erosion process through direct visualization by optical techniques of particles migration using crushed glass samples as model materials.

  10. A MACRO-SCALE SEMI-DISTRIBUTED HYDROLOGICAL MODEL AND APPLICATION TO THE DATONG RIVER VALLEY

    Institute of Scientific and Technical Information of China (English)

    YANG Zhi-feng; LIU Lu-liu; SHEN Zhen-yao; GORDON G. Huang

    2005-01-01

    A daily distributed hydrological model was developed using routine hydro-meteorological data on the basis of the raster DEM and land cover data.Then the model was used to model daily runoff of the Datong River Valley located in the upper catchment of the Yellow River Basin.The runoff comprises surface flow, subsurface flow and ground water flow.Evapotranspiration comprises canopy evaporation, snow sublimation and soil evapotranspiration.The infiltration to the soil was estimated with improved Green-Ampt model, and the potential evapotranspiration is estimated with Morton CRAE method, which only needs the routine meteorological data.Simulation results and the comparison with semi-distributed SLURP hydrological model show that the structure of the model presented herein is reasonable.

  11. A global fingerprint of macro-scale changes in urban structure from 1999 to 2009

    Science.gov (United States)

    Frolking, Steve; Milliman, Tom; Seto, Karen C.; Friedl, Mark A.

    2013-06-01

    Urban population now exceeds rural population globally, and 60-80% of global energy consumption by households, businesses, transportation, and industry occurs in urban areas. There is growing evidence that built-up infrastructure contributes to carbon emissions inertia, and that investments in infrastructure today have delayed climate cost in the future. Although the United Nations statistics include data on urban population by country and select urban agglomerations, there are no empirical data on built-up infrastructure for a large sample of cities. Here we present the first study to examine changes in the structure of the world’s largest cities from 1999 to 2009. Combining data from two space-borne sensors—backscatter power (PR) from NASA’s SeaWinds microwave scatterometer, and nighttime lights (NL) from NOAA’s defense meteorological satellite program/operational linescan system (DMSP/OLS)—we report large increases in built-up infrastructure stock worldwide and show that cities are expanding both outward and upward. Our results reveal previously undocumented recent and rapid changes in urban areas worldwide that reflect pronounced shifts in the form and structure of cities. Increases in built-up infrastructure are highest in East Asian cities, with Chinese cities rapidly expanding their material infrastructure stock in both height and extent. In contrast, Indian cities are primarily building out and not increasing in verticality. This new dataset will help characterize the structure and form of cities, and ultimately improve our understanding of how cities affect regional-to-global energy use and greenhouse gas emissions.

  12. Solving for Micro- and Macro- Scale Electrostatic Configurations Using the Robin Hood Algorithm

    CERN Document Server

    Formaggio, J A; Corona, T J; Stefancic, H; Abraham, H; Gluck, F

    2011-01-01

    We present a novel technique by which highly-segmented electrostatic configurations can be solved. The Robin Hood method is a matrix-inversion algorithm optimized for solving high density boundary element method (BEM) problems. We illustrate the capabilities of this solver by studying two distinct geometry scales: (a) the electrostatic potential of a large volume beta-detector and (b) the field enhancement present at surface of electrode nano-structures. Geometries with elements numbering in the O(10^5) are easily modeled and solved without loss of accuracy. The technique has recently been expanded so as to include dielectrics and magnetic materials.

  13. Transpression / transtension: a model for micro- to macro-scale deformation

    Science.gov (United States)

    Sanderson, David J.

    2014-05-01

    Transpression and transtension were terms introduces by Harland (1971) to define deformation that involves both transcurrent (strike-slip) movement along a zone and compression or extension across it. Sanderson & Marchini (1984) produced a strain model for transpression, and the concept has subsequently been applied in a variety of tectonic settings over a wide range of scales. Transpression is modelled by the simultaneous application of a transcurrent shear and horizontal shortening orthogonal to a block, with no lateral stretch. Sanderson & Marchini originally used two parameters α (the vertical elongation) and γ (the shear strain on the zone boundary) to define the deformation within the block. For constant volume deformation, the shortening across the zone is simply β = α-1, but volume change (Δ) is easily incorporated in the models, where α β = (1+Δ). One may also specify transpression in terms of the strain rates (δɛsgγ) and the direction (A) and amount (S) of convergence/divergence, where tan A = δγ / δɛ. The transpressional model has a number of important implications, which include: It generally leads to triaxial deformation, hence is intrinsically 3-dimensional, e.g. flattening strains characterise transpressional zones, whereas constrictional strains result from transtension. It represents a spectrum of strain states, providing a useful way of classifying deformational styles between generalised compressional, strike-slip and extensional regimes. The vorticity axis will be normal to the shear direction (vertical) and does not need to be parallel to the intermediate principle stain axis. At a convergence angle of A ≡70.5O the incremental and finite strain axes may be differently oriented and this may produce situations where structures may appear to develop in unusual orientations with respect to the finite strain fabrics Both the compressional and shear components contribute to the stretch Sn normal to the zone, where Sn = (α2 + γ2)-1 /2 . Thus the shortening (stretch) measured across a transpression zone (including simple shear zones), by methods such as balancing sections, should not be confused with the parameter β, which measures the convergence of the zone boundaries. It may be applied to zones of deformation on a variety of scales. It has been generalised to include several other components of deformation, including lateral extrusion, vertical shear both parallel and normal to the zone and oblique shear, inclined shear, etc. The controlling parameters may vary spatially within a zone (spatial partitioning) or with time during its evolution (temporal partitioning). In many settings involving oblique convergence, the strike-slip component may be taken up mainly on faults within the zone, whilst the compression is more broadly distributed. Spatial partitioning can allow continuity across the zone boundary (e.g. Robin & Cruden 1994).

  14. From Micro- to Macro-scales in the Heliosphere and Magnetospheres

    CERN Document Server

    Shaikh, Dastgeer; Lu, Q M; Zank, G P

    2010-01-01

    From a broader perspective, the heliosphere and planetary magnetospheres provide a test bed to explore the plasma physics of the Universe. In particular, the underlying nonlinear coupling of different spatial and temporal scales plays a key role in determining the structure and dynamics of space plasmas and electromagnetic fields. Plasmas and fields exhibit both laminar and turbulent properties, corresponding to either well organized or disordered states, and the development of quantitative theoretical and analytical descriptions from physics based first principles is a profound challenge. Limited observations and complications introduced by geometry and physical parameters conspire to complicate the problem. Dimensionless scaling analysis and statistical methods are universally applied common approaches that allow for the application of related ideas to multiple physical problems. We discuss several examples of the interplay between the scales in a variety of space plasma environments, as exemplified in the ...

  15. Characterizing Micro- and Macro-Scale Seismicity from Bayou Corne, Louisiana

    Science.gov (United States)

    Baig, A. M.; Urbancic, T.; Karimi, S.

    2013-12-01

    The initiation of felt seismicity in Bayou Corne, Louisiana, coupled with other phenomena detected by residents on the nearby housing development, prompted a call to install a broadband seismic network to monitor subsurface deformation. The initial deployment was in place to characterize the deformation contemporaneous with the formation of a sinkhole located in close proximity to a salt dome. Seismic events generated during this period followed a swarm-like behaviour with moment magnitudes culminating around Mw2.5. However, the seismic data recorded during this sequence suffer from poor signal to noise, onsets that are very difficult to pick, and the presence of a significant amount of energy arriving later in the waveforms. Efforts to understand the complexity in these waveforms are ongoing, and involve invoking the complexities inherent in recording in a highly attenuating swamp overlying a complex three-dimensional structure with the strong material property contrast of the salt dome. In order to understand the event character, as well as to locally lower the completeness threshold of the sequence, a downhole array of 15 Hz sensors was deployed in a newly drilled well around the salt dome. Although the deployment lasted a little over a month in duration, over 1000 events were detected down to moment magnitude -Mw3. Waveform quality tended to be excellent, with very distinct P and S wave arrivals observable across the array for most events. The highest magnitude events were seen as well on the surface network and allowed for the opportunity to observe the complexities introduced by the site effects, while overcoming the saturation effects on the higher-frequency downhole geophones. This hybrid downhole and surface array illustrates how a full picture of subsurface deformation is only made possible by combining the high-frequency downhole instrumentation to see the microseismicity complemented with a broadband array to accurately characterize the source parameters for the larger magnitude events. Our presentation is focused on investigating this deformation, characterizing the scaling behaviour and the other source processes by taking advantage of the wide-band afforded to us through the deployment.

  16. Dynamic monitoring and prediction of Dianchi Lake cyanobacteria outbreaks in the context of rapid urbanization.

    Science.gov (United States)

    Luo, Yi; Yang, Kun; Yu, Zhenyu; Chen, Junyi; Xu, Yufei; Zhou, Xiaolu; Yang, Yang

    2017-02-01

    Water crises have been among the most serious environmental problems worldwide since the twenty-first century. A water crisis is marked by a severe shortage of water resources and deteriorating water quality. As an important component of water resources, lake water quality has deteriorated rapidly in the context of fast urbanization and climate change. This deterioration has altered the water ecosystem structure and influenced lake functionality. To curb these trends, various strategies and procedures have been used in many urban lakes. Among these procedures, accurate and responsive water environment monitoring is the basis of the forecasting and prevention of large-scale cyanobacteria outbreaks and improvement of water quality. To dynamically monitor and predict the outbreak of cyanobacteria in Dianchi Lake, in this study, wireless sensors networks (WSNs) and the geographic information system (GIS) are used to monitor water quality at the macro-scale and meso-scale. Historical, real-time water quality and weather condition data were collected, and a combination prediction model (adaptive grey model (AGM) and back propagation artificial neural network (BPANN)) was proposed. The correlation coefficient (R) of the simulation experiment reached 0.995. Moreover, we conducted an empirical experiment in Dianchi Lake, Yunnan, China using the proposed method. R was 0.93, and the predicting error was 4.77. The results of the experiment suggest that our model has good performance for water quality prediction and can forecast cyanobacteria outbreaks. This system provides responsive forewarning and data support for lake protection and pollution control.

  17. 一次冬季锋面暴风雪天气过程的斜压边界层特征的观测分析%Observational Analyses of Baroclinic Boundary Layer Characteristics during One Frontal Winter Snowstorm

    Institute of Scientific and Technical Information of China (English)

    许吟隆; 钱粉兰; 陈陟; 李诗明; 周明煜

    2002-01-01

    The evolution and characteristics of the baroclinic boundary layer for one frontal winter snowstorm were analyzed by using the well-documented dataset during Intensive Observation Period (IOP) 17 of STORM-FEST. It is found that when the warm moist air was lifted across the front, a great amount of la tent heat release because of snowing increased the frontal temperature contrast to intensify frontogenesis. Itis shown in the zig-zag section diagram of potential temperature that when the frontogenesis got stronger, a cold trough was formed and both low-level jet (LLJ) and upper-level jet (ULJ) emerged ahead of the front.In the strongest stage of frontogenesis, the frontal contrast of potential temperature of cold trough reached as high as 20 K. Hereafter the LLJ ahead of the front tended to weaken and the LLJ behind the front tended to strengthen. The frontal circulation system was dominated by the cold air advection behind the front,which transported the cold air behind the front forward to the warm area ahead of the front to weaken the cold trough and finally frontolysis occurred. It is shown by the analyses of turbulent characteristics of front al baroclinic boundary-layer that the vertical shear (wv) above the boundary layer was very large, and the pumping of the strong wind shear in turbulent energy budget made the characteristic variables within the PBL well mixed. Sufficient moisture carried by southerly flow from the Mexico Gulf, and the strong baroclinity of the frontal boundary layer played key roles in this frontal winter snowstorm, and the large-scale ULJ behind the cold front is also advantageous to the development of the convective boundary layer.%对STORM-FEST IOP 1 7一次冬季锋面暴风雪天气过程的斜压边界层结构演变及特征进行了分析.发现:暖湿空气沿锋面抬升凝结成云,产生降水过程中释放的大量潜热显著增加锋两侧的水平温度差异,产生锋生.与锋生相伴,在锋前产生低空急流和高

  18. Predicting cell viability within tissue scaffolds under equiaxial strain: multi-scale finite element model of collagen-cardiomyocytes constructs.

    Science.gov (United States)

    Elsaadany, Mostafa; Yan, Karen Chang; Yildirim-Ayan, Eda

    2017-01-16

    Successful tissue engineering and regenerative therapy necessitate having extensive knowledge about mechanical milieu in engineered tissues and the resident cells. In this study, we have merged two powerful analysis tools, namely finite element analysis and stochastic analysis, to understand the mechanical strain within the tissue scaffold and residing cells and to predict the cell viability upon applying mechanical strains. A continuum-based multi-length scale finite element model (FEM) was created to simulate the physiologically relevant equiaxial strain exposure on cell-embedded tissue scaffold and to calculate strain transferred to the tissue scaffold (macro-scale) and residing cells (micro-scale) upon various equiaxial strains. The data from FEM were used to predict cell viability under various equiaxial strain magnitudes using stochastic damage criterion analysis. The model validation was conducted through mechanically straining the cardiomyocyte-encapsulated collagen constructs using a custom-built mechanical loading platform (EQUicycler). FEM quantified the strain gradients over the radial and longitudinal direction of the scaffolds and the cells residing in different areas of interest. With the use of the experimental viability data, stochastic damage criterion, and the average cellular strains obtained from multi-length scale models, cellular viability was predicted and successfully validated. This methodology can provide a great tool to characterize the mechanical stimulation of bioreactors used in tissue engineering applications in providing quantification of mechanical strain and predicting cellular viability variations due to applied mechanical strain.

  19. Large-eddy simulation of the atmospheric boundary layer: Influence of unsteady forcing, baroclinicity, inversion strength and stability on the wind profile

    DEFF Research Database (Denmark)

    Pedersen, Jesper Grønnegaard

    of the large-scale pressure forcing, when using LES for prediction of real-world wind profiles. In the Høvsøre case study, simulated wind speeds agree well with measurements throughout the ABL, but only when the applied forcing follows a height- and time-dependent pressure gradient estimated from continuous...... facilitate the formation of a super-geostrophic jet near the top of the ABL. It is considered to be a rare phenomena in the real-world ABL, and is not accounted for by the analytical models of the wind shear included in this study. It is furthermore shown that the considered wind profile model can...... the site in Hamburg are insufficient for accurate estimation of the driving pressure gradient, and that phenomena such as large-scale subsidence and advection also should be included in the LES for accurate wind profile prediction. A range of simulations of more idealized conditions are performed to study...

  20. AN EXPERIMENTAL STUDY ON THE β EFFECT ACTING ONTHE THERMAL STRUCTURE OF BAROCLINIC WAVES IN A ROTATING ANNULUS%β平面上斜压波热力结构特性的实验研究

    Institute of Scientific and Technical Information of China (English)

    林上金; 仲孝恭; 成新喜; 魏岗; 周凯; 刘宇迪

    2001-01-01

    首次用转环实验模拟方法研究了β效应对斜压波热力结构的影响,发现β效应有抑制流动的水平混合和垂直混合的作用,使流动趋于正压;β平面上急流随高度降低而减弱,在急流的内外两侧各有一个无量纲温度值分布的突跃区,它们的空间结构与大气环流中的极锋锋区和北极锋锋区的结构相似.%The rotating annulus experiment is an important means in the study of rotating fluid dynamics. Geophysical fluid flows includes the atmosphere circulation. The generation, development and dynamics of the baroclinic can be simulated by rotating fluid annulus experiment.Therefor, the dynamic of the large scale quasi-geostrophic of atmosphere and ocean can be understand more deeply. The β effect is an important factor acting on the geophysical fluid flow. But there is no general accepted point of view in the important the β effect. There are two points of view to characters of atmospheric long wave, i.e., The one based on the classical theory, the other newer point of view believes that it is not the Rossby wave, but just a barolinic wave influenced by the β effect. An experiment study about the β effect action on the baroclinic wave in an rotating annulus is outlined in this paper. The quantization measures of temperature field of fluid flow in the rotating annulus has been accomplishes and the qualitative analysis about the inner thermal structure of the flow that acted by theβ effect is accomplished. The equipment of the experiment is a rotating annulus in which the inner wall and outer wall are kept at low and high temperature by a temperature control. The inner temperature of the flow is detected by the thermodetector with three dimensional fine grid. Comparing a group of the inner thermal structure of same surface flow pattern on the f plane and the β effect plane, the following results have been gotten in this paper. (1) On the f plane, the fluid flow are obviously. The

  1. Spectral Analysis of Dow Jones Index and Comparison with Model Predicted Cycles During 1900-2005

    CERN Document Server

    Selvam, A M

    2006-01-01

    The day-to day fluctuations of Dow Jones Index exhibit fractal fluctuations, namely, a zigzag pattern of successive increases followed by decreases on all space-time scales. Self-similar fractal fluctuations are generic to dynamical systems in nature and imply long-range space-time correlations. The apparently unpredictable (chaotic) fluctuations of dynamical systems exhibit underlying order with the power spectra exhibiting inverse power law form, now identified as self-organized criticality. The physics of self-organized criticality is not yet identified. A general systems theory developed by the author shows that self-similar fractal fluctuations are signatures of quantum-like chaos in dynamical systems of all size scales ranging from the subatomic dynamics of quantum systems to macro-scale fluid flows. The model predicts the universal inverse power-law form of the statistical normal distribution for the power spectra of fractal space-time fluctuations of dynamical systems. In this paper it is shown that t...

  2. Predicting the steady state thickness of passive films in order to prevent degradations of implant

    CERN Document Server

    Geringer, Jean; Macdonald, Digby D

    2014-01-01

    Some implants have approximately a lifetime of 15 years. The femoral stem, for example, should be made of 316L/316LN stainless steel. Fretting corrosion, friction under small displacements, should occur during human gait, due to repeated loadings and un-loadings, between stainless steel and bone for instance. Some experimental investigations of fretting corrosion have been practiced. As well known, metallic alloys and especially stainless steels are covered with a passive film that prevents from the corrosion and degradation. This passive layer of few nanometers, at ambient temperature, is the key of our civilization according to some authors. This work is dedicated to predict the passive layer thicknesses of stainless steel under fretting corrosion with a specific emphasis on the role of proteins. The model is based on the Point Defect Model (micro scale) and an update of the model on the friction process (micro-macro scale). Genetic algorithm was used for finding solution of the problem. The major results a...

  3. Multi-level machine learning prediction of protein–protein interactions in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Julian Zubek

    2015-07-01

    Full Text Available Accurate identification of protein–protein interactions (PPI is the key step in understanding proteins’ biological functions, which are typically context-dependent. Many existing PPI predictors rely on aggregated features from protein sequences, however only a few methods exploit local information about specific residue contacts. In this work we present a two-stage machine learning approach for prediction of protein–protein interactions. We start with the carefully filtered data on protein complexes available for Saccharomyces cerevisiae in the Protein Data Bank (PDB database. First, we build linear descriptions of interacting and non-interacting sequence segment pairs based on their inter-residue distances. Secondly, we train machine learning classifiers to predict binary segment interactions for any two short sequence fragments. The final prediction of the protein–protein interaction is done using the 2D matrix representation of all-against-all possible interacting sequence segments of both analysed proteins. The level-I predictor achieves 0.88 AUC for micro-scale, i.e., residue-level prediction. The level-II predictor improves the results further by a more complex learning paradigm. We perform 30-fold macro-scale, i.e., protein-level cross-validation experiment. The level-II predictor using PSIPRED-predicted secondary structure reaches 0.70 precision, 0.68 recall, and 0.70 AUC, whereas other popular methods provide results below 0.6 threshold (recall, precision, AUC. Our results demonstrate that multi-scale sequence features aggregation procedure is able to improve the machine learning results by more than 10% as compared to other sequence representations. Prepared datasets and source code for our experimental pipeline are freely available for download from: http://zubekj.github.io/mlppi/ (open source Python implementation, OS independent.

  4. Multi-level machine learning prediction of protein-protein interactions in Saccharomyces cerevisiae.

    Science.gov (United States)

    Zubek, Julian; Tatjewski, Marcin; Boniecki, Adam; Mnich, Maciej; Basu, Subhadip; Plewczynski, Dariusz

    2015-01-01

    Accurate identification of protein-protein interactions (PPI) is the key step in understanding proteins' biological functions, which are typically context-dependent. Many existing PPI predictors rely on aggregated features from protein sequences, however only a few methods exploit local information about specific residue contacts. In this work we present a two-stage machine learning approach for prediction of protein-protein interactions. We start with the carefully filtered data on protein complexes available for Saccharomyces cerevisiae in the Protein Data Bank (PDB) database. First, we build linear descriptions of interacting and non-interacting sequence segment pairs based on their inter-residue distances. Secondly, we train machine learning classifiers to predict binary segment interactions for any two short sequence fragments. The final prediction of the protein-protein interaction is done using the 2D matrix representation of all-against-all possible interacting sequence segments of both analysed proteins. The level-I predictor achieves 0.88 AUC for micro-scale, i.e., residue-level prediction. The level-II predictor improves the results further by a more complex learning paradigm. We perform 30-fold macro-scale, i.e., protein-level cross-validation experiment. The level-II predictor using PSIPRED-predicted secondary structure reaches 0.70 precision, 0.68 recall, and 0.70 AUC, whereas other popular methods provide results below 0.6 threshold (recall, precision, AUC). Our results demonstrate that multi-scale sequence features aggregation procedure is able to improve the machine learning results by more than 10% as compared to other sequence representations. Prepared datasets and source code for our experimental pipeline are freely available for download from: http://zubekj.github.io/mlppi/ (open source Python implementation, OS independent).

  5. Research on Two-scale Numerical Simulation Method for Predicting Pressure Drop of Fibrous Filter Medium%纤维滤料压力损失预测的两尺度数值模拟方法研究

    Institute of Scientific and Technical Information of China (English)

    王伟; 吴金辉; 王政

    2012-01-01

    A two-scale numerical simulation approach that can reduce the amount of computation, increase the predictive accuracy and allow the process of computation carrying on a personal computer was proposed to predict the pressure drop of fibrous filter medium of entire thickness. A micro-scale model and a macro-scale model of the selected (typical) glass fibrous filter medium(H13) were built. The pressure drop of micro-scale model was computed using Fluent software and the results were then used in the macro-scale model developed by porous model in Fluent software in order to predict the pressure drop of fibrous filter medium of entire thickness. The result shows that the number of grids in simulating the flow in the micro-scale model and the macro-scale model of fibrous filter medium are about half a million and 130 thousand respectively that can be easily computed on PC. The predicted values are compared with experimental values and values of theoretical models in the literature. The results indicate that the pressure drop linearly increases with the surface velocity. The predicted values are in excellent agreement with the experimental results and the relative error is 10.7% -23.7%. But the values of theoretical models are far away from the predicted values and experimental values.%为解决利用数值模拟方法对纤维滤料全厚度方向的压力损失进行预测时计算量大、准确性低、PC机上难以进行的问题,提出了一种两尺度数值模拟方法.建立了所选定的一种典型玻璃纤维滤料(H13)微观及宏观模型.利用Fluent软件对微观模型的压力损失进行数值计算,并将模拟结果应用到基于Fluent软件多孔介质模型建立的宏观模型中,用以预测纤维滤料全厚度方向压力损失.结果表明,纤维滤料微观、宏观模型网格划分数量分别为约50万和13万,满足PC机的运算要求.压力损失模拟预测值、理论值以及试验值的对比表明,纤维滤料压力损失随面

  6. Impact of satellite data assimilation on the predictability of monsoon intraseasonal oscillations in a regional model

    KAUST Repository

    Parekh, Anant

    2017-04-07

    This study reports the improvement in the predictability of circulation and precipitation associated with monsoon intraseasonal oscillations (MISO) when the initial state is produced by assimilating Atmospheric Infrared Sounder (AIRS) retrieved temperature and water vapour profiles in Weather Research Forecast (WRF) model. Two separate simulations are carried out for nine years (2003 to 2011) . In the first simulation, forcing is from National Centers for Environmental Prediction (NCEP, CTRL) and in the second, apart from NCEP forcing, AIRS temperature and moisture profiles are assimilated (ASSIM). Ten active and break cases are identified from each simulation. Three dimensional temperature states of identified active and break cases are perturbed using twin perturbation method and carried out predictability tests. Analysis reveals that the limit of predictability of low level zonal wind is improved by four (three) days during active (break) phase. Similarly the predictability of upper level zonal wind (precipitation) is enhanced by four (two) and two (four) days respectively during active and break phases. This suggests that the initial state using AIRS observations could enhance predictability limit of MISOs in WRF. More realistic baroclinic response and better representation of vertical state of atmosphere associated with monsoon enhance the predictability of circulation and rainfall.

  7. Predicting the steady state thickness of passive films with the Point Defect Model in fretting corrosion experiments

    CERN Document Server

    Geringer, Jean; Taylor, Mathew L

    2013-01-01

    Some implants have approximately a lifetime of 15 years. The femoral stem, for example, should be made of 316L/316LN stainless steel. Fretting corrosion, friction under small displacements, should occur during human gait, due to repeated loadings and un-loadings, between stainless steel and bone for instance. Some experimental investigations of fretting corrosion have been practiced. As well known, metallic alloys and especially stainless steels are covered with a passive film that prevents from the corrosion and degradation. This passive layer of few nanometers, at ambient temperature, is the key of our civilization according to some authors. This work is dedicated to predict the passive layer thicknesses of stainless steel under fretting corrosion with a specific emphasis on the role of proteins. The model is based on the Point Defect Model (micro scale) and an update of the model on the friction process (micro-macro scale). Genetic algorithm was used for finding solution of the problem. The major results a...

  8. A computational remodeling approach to predict the physiological architecture of the collagen fibril network in corneo-scleral shells.

    Science.gov (United States)

    Grytz, Rafael; Meschke, Günther

    2010-04-01

    Organized collagen fibrils form complex networks that introduce strong anisotropic and highly nonlinear attributes into the constitutive response of human eye tissues. Physiological adaptation of the collagen network and the mechanical condition within biological tissues are complex and mutually dependent phenomena. In this contribution, a computational model is presented to investigate the interaction between the collagen fibril architecture and mechanical loading conditions in the corneo-scleral shell. The biomechanical properties of eye tissues are derived from the single crimped fibril at the micro-scale via the collagen network of distributed fibrils at the meso-scale to the incompressible and anisotropic soft tissue at the macro-scale. Biomechanically induced remodeling of the collagen network is captured on the meso-scale by allowing for a continuous re-orientation of preferred fibril orientations and a continuous adaptation of the fibril dispersion. The presented approach is applied to a numerical human eye model considering the cornea and sclera. The predicted fibril morphology correlates well with experimental observations from X-ray scattering data.

  9. Macro-scale complexity of nano- to micro-scale architecture of olivine crystals through an iodine vapour transport mechanism

    Indian Academy of Sciences (India)

    Raymond L D Whitby; Takahiro Fukuda; Toru Maekawa

    2014-04-01

    The production of nano- to micro-scale olivine (magnesium and iron silicate) crystals has been achieved at relatively low temperatures through an iodine vapour transport of the metal onto amorphous silicon dioxide. The process occurs down a temperature gradient from 800 to 600°C yielding high quality crystals with long range crystallinity, highly complex interconnectivity and intricate macroscale architecture. Scanning electron microscopy (SEM) imaging of the substrate before and after the reaction reveals that the amorphous silicon oxide species is mobile, due to the lack of correlation between the silicon oxide layer and the final olivine particles, leading to a vapour–liquid–solid or vapour–solid growth mechanism. This technique demonstrates a facile, low temperature synthetic route towards olivine crystals with nano- to micro-scale dimensions.

  10. A Spatially Explicit and Seasonally Varying Cholera Prevalence Model With Distributed Macro-Scale Environmental and Hydroclimatic Forcings

    Science.gov (United States)

    Akanda, A. S.; Jutla, A. S.; Eltahir, E. A.; Islam, S.

    2011-12-01

    Despite major advances in the ecological and microbiological understanding of the bacterium Vibrio cholerae, the role of underlying large-scale processes in the progression of the cholera disease in space and time is not well understood. Here, we present a spatially explicit and seasonally varying coupled hydroclimatology-epidemiology model for understanding regional scale cholera prevalence in response to large scale hydroclimatic and environmental forcings. Our results show that environmental cholera transmission can be modulated by two spatially and seasonally distinct mechanisms - influenced by dry and wet season hydrologic determinants. The model is applied to the Ganges-Brahmaputra-Meghna Basin areas in Bangladesh to simulate spatially explicit cholera prevalence rates, and validated with long-term cholera data from Dhaka and shorter-term records from regional surveillance locations. The model reproduces the variability of cholera prevalence at monthly, seasonal, and interannual timescales and highlights the role of asymmetric large scale hydroclimatic processes as the dominant controls. Our findings have important implications for formulating effective cholera intervention strategies, and for understanding the impacts of changing climate patterns on seasonal cholera transmission.

  11. From macro-scale to micro-scale computational anatomy: a perspective on the next 20 years.

    Science.gov (United States)

    Mori, Kensaku

    2016-10-01

    This paper gives our perspective on the next two decades of computational anatomy, which has made great strides in the recognition and understanding of human anatomy from conventional clinical images. The results from this field are now used in a variety of medical applications, including quantitative analysis of organ shapes, interventional assistance, surgical navigation, and population analysis. Several anatomical models have also been used in computational anatomy, and these mainly target millimeter-scale shapes. For example, liver-shape models are almost completely modeled at the millimeter scale, and shape variations are described at such scales. Most clinical 3D scanning devices have had just under 1 or 0.5 mm per voxel resolution for over 25 years, and this resolution has not changed drastically in that time. Although Z-axis (head-to-tail direction) resolution has been drastically improved by the introduction of multi-detector CT scanning devices, in-plane resolutions have not changed very much either. When we look at human anatomy, we can see different anatomical structures at different scales. For example, pulmonary blood vessels and lung lobes can be observed in millimeter-scale images. If we take 10-µm-scale images of a lung specimen, the alveoli and bronchiole regions can be located in them. Most work in millimeter-scale computational anatomy has been done by the medical-image analysis community. In the next two decades, we encourage our community to focus on micro-scale computational anatomy. In this perspective paper, we briefly review the achievements of computational anatomy and its impacts on clinical applications; furthermore, we show several possibilities from the viewpoint of microscopic computational anatomy by discussing experimental results from our recent research activities.

  12. Three-dimensional Biomimetic Technology: Novel Biorubber Creates Defined Micro- and Macro-scale Architectures in Collagen Hydrogels.

    Science.gov (United States)

    Rodriguez-Rivera, Veronica; Weidner, John W; Yost, Michael J

    2016-02-12

    Tissue scaffolds play a crucial role in the tissue regeneration process. The ideal scaffold must fulfill several requirements such as having proper composition, targeted modulus, and well-defined architectural features. Biomaterials that recapitulate the intrinsic architecture of in vivo tissue are vital for studying diseases as well as to facilitate the regeneration of lost and malformed soft tissue. A novel biofabrication technique was developed which combines state of the art imaging, three-dimensional (3D) printing, and selective enzymatic activity to create a new generation of biomaterials for research and clinical application. The developed material, Bovine Serum Albumin rubber, is reaction injected into a mold that upholds specific geometrical features. This sacrificial material allows the adequate transfer of architectural features to a natural scaffold material. The prototype consists of a 3D collagen scaffold with 4 and 3 mm channels that represent a branched architecture. This paper emphasizes the use of this biofabrication technique for the generation of natural constructs. This protocol utilizes a computer-aided software (CAD) to manufacture a solid mold which will be reaction injected with BSA rubber followed by the enzymatic digestion of the rubber, leaving its architectural features within the scaffold material.

  13. Experimental Investigation on Effect of Fin Height on Microscale Heat Transfer and Fluid Flow for Macro Scale Industrial Applications

    Science.gov (United States)

    Cheng, K. X.; Goh, A. L.; Hadi, M.; Ooi, K. T.

    2017-03-01

    Microchannel for macro geometry application is gaining popularity particularly in aerospace, biomedical and photovoltaic. A novel method of employing microchannel in macro geometry at lower cost using conventional machining methods has been developed. A solid cylinder on outer diameter 19.4 mm is placed concentrically into a copper pipe of inner diameter 20 mm, forming an annular microchannel with 300 μm gap. This study takes a step further by introducing surface profile of different heights on the surface of solid cylinder and investigating the effect on two main design objectives- increasing heat removal capability at same pumping power and reducing pumping power for the same heat removal duty. Four surface profiles -parallel fins as well as fins with height of 0.1, 0.2 and 0.3 mm, were investigated experimentally at constant heat flux at Reynolds number from 690 to 4600. The amount of fluid in the microchannel, channel length of 30 mm, bifurcating angle of 75 degrees and mean hydraulic diameter of 600 μm are kept as constant parameters. A plain insert is used as benchmark for comparison of enhancement. In this study, insert with fins of 0.3 mm attains the highest enhancement of 43 percent increment in heat transfer as compared to plain insert using the same pumping power. While keeping the heat removal duty constant, the same insert is able to perform the duty using less than 50 percent the pumping power required by the plain insert at low Reynolds numbers.

  14. Meso-Scale and Macro-Scale Analysis of the Geochemical and Physical Processes Responsible for Acid Rock Drainage

    Science.gov (United States)

    Otwinowski, Matthew

    1997-08-01

    We have developed a computer model which describes the geochemical and physical processes responsible for acid drainage from waste rock piles. The model is in the form of coupled nonlinear PDEs which describe: the kinetics of the chemical reactions, the release of contaminants, the generation of energy due to the exothermic oxidation of sulphides, the diffusive and convective transport of oxygen and water, and the transport of energy by conduction and convection. The meso-scale and large-scale characterization of waste rock and waste rock piles is discussed. We show that long-term leaching rates are inversely proportional to the square of particle diameter and that the previously used models underestimate the particle size effect on long-term sulphide oxidation. Experimental data on rock fragmentation are used for a fractal statistical characterization of waste rock piles. The acid generation rates, oxygen consumption rates and temperature profiles have been determined for piles containing from fifty thousand to five hundred thousand tonnes of waste rock. The thermodynamic instabilities, which occur at certain critical values of pile height, are responsible for thermodynamic catastrophes which result in a rapid increase of acid generation rates. The critical height is determined by the values of sulphide concentration, particle size, pile porosity and other factors. The numerical code is based on the finite elements method with an adaptive grid generator. abstract.

  15. Modelling PM10 aerosol data from the Qalabotjha low-smoke fuels macro-scale experiment in South Africa

    CSIR Research Space (South Africa)

    Engelbrecht, JP

    2000-03-30

    Full Text Available D-grade (i.e. poor quality) coal is widely used for household cooking and heating purposes by lower-income urban communities in South Africa. The smoke from the combustion of coal has had a severe impact on the health of society in the townships...

  16. Glaciers and small ice caps in the macro-scale hydrological cycle - an assessment of present conditions and future changes

    Science.gov (United States)

    Lammers, Richard; Hock, Regine; Prusevich, Alexander; Bliss, Andrew; Radic, Valentina; Glidden, Stanley; Grogan, Danielle; Frolking, Steve

    2014-05-01

    Glacier and small ice cap melt water contributions to the global hydrologic cycle are an important component of human water supply and for sea level rise. This melt water is used in many arid and semi-arid parts of the world for direct human consumption as well as indirect consumption by irrigation for crops, serving as frozen reservoirs of water that supplement runoff during warm and dry periods of summer when it is needed the most. Additionally, this melt water reaching the oceans represents a direct input to sea level rise and therefore accurate estimates of this contribution have profound economic and geopolitical implications. It has been demonstrated that, on the scale of glacierized river catchments, land surface hydrological models can successfully simulate glacier contribution to streamflow. However, at global scales, the implementation of glacier melt in hydrological models has been rudimentary or non-existent. In this study, a global glacier mass balance model is coupled with the University of New Hampshire Water Balance/Transport Model (WBM) to assess recent and projected future glacier contributions to the hydrological cycle over the global land surface (excluding the ice sheets of Greenland and Antarctica). For instance, results of WBM simulations indicate that seasonal glacier melt water in many arid climate watersheds comprises 40 % or more of their discharge. Implicitly coupled glacier and WBM models compute monthly glacier mass changes and resulting runoff at the glacier terminus for each individual glacier from the globally complete Randolph Glacier Inventory including over 200 000 glaciers. The time series of glacier runoff is aggregated over each hydrological modeling unit and delivered to the hydrological model for routing downstream and mixing with non-glacial contribution of runoff to each drainage basin outlet. WBM tracks and uses glacial and non-glacial components of the in-stream water for filling reservoirs, transfers of water between drainage basins (inter-basin hydrological transfers), and irrigation along the global system of rivers with net discharge to the ocean. Climate scenarios from global climate models prepared for IPCC AR5 are used to explore an expected range of possible future glacier outflow variability to estimate the impacts on human use of these valuable waters and their poorly understood net contribution to sea level change.

  17. 斜压Ertel-Rossby不变量在梅雨锋降水过程中的研究与应用%The Study and Application of Baroclinic Ertel-Rossby Invariant in Meiyu Front Precipitation Process

    Institute of Scientific and Technical Information of China (English)

    高守亭; 梁生俊; 邓涤菲; 林青

    2012-01-01

    绝热无摩擦下,位涡(PV)的守恒性、不可渗透性和可反演性使之非常广泛地应用在中高纬度天气学诊断分析中,但由于其本身不包含力管项,无法描述强烈天气的快速流形等局限性,因此分析了Zdunkowski and Bott(2003)提出的斜压Ertrl-Rossby不变量(ERI),结果表明,绝热无摩擦条件下的ERI在其表达式中就已经明确地包含了螺旋度和PV的表达式,同时也涵盖了斜压大气中的力管项效应,可以描述快速流形的天气系统,具有PV所不能取代的优点,这使得它具有非常广泛的潜在应用价值.在此基础上,还利用ERI诊断了2003年7月3~6日的一次梅雨降水过程,结果表明,ERI完整地刻画了这次降水带南移及降水强度变化的特点,随着24h累积降水带的移动,ERI低值区也随之移动,二者吻合非常好.和PV相比,ERI对降水落区及强度变化的诊断能力更强.%In adiabatic and frictionless flow, Potential Vorticity (PV), characterized by its features of conservation, impermeability, and inversion, is widely used in diagnosis and analysis of the weather system over middle-high latitude.Due to its limitations of excluding the term of solenoid and of incapable of describing "fast-manifold" severe weather system, baroclinic Ertel-Rossby Invariant (ERI) proposed by Zdunkowski and Bott (2003) is analyzed and applied. The results show that under the condition of adiabatic and frictionless atmosphere, the expression of ERI includes the helicity. PV, and solenoid, and it can depict the "fast-manifold" systems, which make it possess huge potential practical value. Furthermore, the authors invoke ERI to diagnose a Meiyu front precipitation process from 3 Jul to 6 Jul 2003. The experiment reveals that the minimum of ERI coincides well with the 24-h accumulated rain band. Compared to PV, ERI is much capable in depicting and diagnosing the rainfall areas and rainfall amount.

  18. Bed load transport in a very steep mountain stream (Riedbach, Switzerland): Measurement and prediction

    Science.gov (United States)

    Schneider, Johannes M.; Rickenmann, Dieter; Turowski, Jens M.; Schmid, Bastian; Kirchner, James W.

    2016-12-01

    Compared to lower-gradient channels, steep mountain streams typically have rougher beds and shallower flow depths, making macro-scale flow resistance (due to, e.g., immobile boulders and irregular bedforms) more important as controls on sediment transport. The marked differences in hydraulics, flow resistance, and grain mobility between steep and lower-gradient streams raise the question of whether the same equations can predict bed load transport rates across wide ranges of channel gradients. We studied a steep, glacier-fed mountain stream (Riedbach, Ct. Valais, Switzerland) that provides a natural experiment for exploring how stream gradients affect bed load transport rates. The streambed gradient increases over a 1 km stream reach by roughly one order of magnitude (from 3% to 38%), while flow discharge and width remain approximately constant. Sediment transport rates were determined in the 3% reach using Bunte bed load traps and in the 38% reach using the Swiss plate geophone system. Despite a ten-fold increase in bed gradient, bed load transport rates did not increase substantially. Observed transport rates for these two very different bed gradients could be predicted reasonably well by using a flow resistance partitioning approach to account for increasing bed roughness (D84 changes from 0.17 m to 0.91 m) within a fractional bed load transport equation. This suggests that sediment transport behavior across this large range of steep slopes agrees with patterns established in previous studies for both lower-gradient and steep reaches, and confirms the applicability of the flow resistance and bed load transport equations at very steep slopes.

  19. Micromechanics model for predicting anisotropic electrical conductivity of carbon fiber composite materials

    Science.gov (United States)

    Haider, Mohammad Faisal; Haider, Md. Mushfique; Yasmeen, Farzana

    2016-07-01

    Heterogeneous materials, such as composites consist of clearly distinguishable constituents (or phases) that show different electrical properties. Multifunctional composites have anisotropic electrical properties that can be tailored for a particular application. The effective anisotropic electrical conductivity of composites is strongly affected by many parameters including volume fractions, distributions, and orientations of constituents. Given the electrical properties of the constituents, one important goal of micromechanics of materials consists of predicting electrical response of the heterogeneous material on the basis of the geometries and properties of the individual phases, a task known as homogenization. The benefit of homogenization is that the behavior of a heterogeneous material can be determined without resorting or testing it. Furthermore, continuum micromechanics can predict the full multi-axial properties and responses of inhomogeneous materials, which are anisotropic in nature. Effective electrical conductivity estimation is performed by using classical micromechanics techniques (composite cylinder assemblage method) that investigates the effect of the fiber/matrix electrical properties and their volume fractions on the micro scale composite response. The composite cylinder assemblage method (CCM) is an analytical theory that is based on the assumption that composites are in a state of periodic structure. The CCM was developed to extend capabilities variable fiber shape/array availability with same volume fraction, interphase analysis, etc. The CCM is a continuum-based micromechanics model that provides closed form expressions for upper level length scales such as macro-scale composite responses in terms of the properties, shapes, orientations and constituent distributions at lower length levels such as the micro-scale.

  20. Predicting future of predictive analysis

    OpenAIRE

    Piyush, Duggal

    2014-01-01

    With enormous growth in analytical data and insight about advantage of managing future brings Predictive Analysis in picture. It really has potential to be called one of efficient and competitive technologies that give an edge to business operations. The possibility to predict future market conditions and to know customers’ needs and behavior in advance is the area of interest of every organization. Other areas of interest may be maintenance prediction where we tend to predict when and where ...

  1. Non-linear behaviour of electrical parameters in porous, water-saturated rocks: a model to predict pore size distribution

    Science.gov (United States)

    Hallbauer-Zadorozhnaya, Valeriya; Santarato, Giovanni; Abu Zeid, Nasser

    2015-08-01

    In this paper, two separate but related goals are tackled. The first one is to demonstrate that in some saturated rock textures the non-linear behaviour of induced polarization (IP) and the violation of Ohm's law not only are real phenomena, but they can also be satisfactorily predicted by a suitable physical-mathematical model, which is our second goal. This model is based on Fick's second law. As the model links the specific dependence of resistivity and chargeability of a laboratory sample to the injected current and this in turn to its pore size distribution, it is able to predict pore size distribution from laboratory measurements, in good agreement with mercury injection capillary pressure test results. This fact opens up the possibility for hydrogeophysical applications on a macro scale. Mathematical modelling shows that the chargeability acquired in the field under normal conditions, that is at low current, will always be very small and approximately proportional to the applied current. A suitable field test site for demonstrating the possible reliance of both resistivity and chargeability on current was selected and a specific measuring strategy was established. Two data sets were acquired using different injected current strengths, while keeping the charging time constant. Observed variations of resistivity and chargeability are in agreement with those predicted by the mathematical model. These field test data should however be considered preliminary. If confirmed by further evidence, these facts may lead to changing the procedure of acquiring field measurements in future, and perhaps may encourage the design and building of a new specific geo-resistivity meter. This paper also shows that the well-known Marshall and Madden's equations based on Fick's law cannot be solved without specific boundary conditions.

  2. Effects of optimal initial errors on predicting the seasonal reduction of the upstream Kuroshio transport

    Science.gov (United States)

    Zhang, Kun; Wang, Qiang; Mu, Mu; Liang, Peng

    2016-10-01

    With the Regional Ocean Modeling System (ROMS), we realistically simulated the transport variations of the upstream Kuroshio (referring to the Kuroshio from its origin to the south of Taiwan), particularly for the seasonal transport reduction. Then, we investigated the effects of the optimal initial errors estimated by the conditional nonlinear optimal perturbation (CNOP) approach on predicting the seasonal transport reduction. Two transport reduction events (denoted as Event 1 and Event 2) were chosen, and CNOP1 and CNOP2 were obtained for each event. By examining the spatial structures of the two types of CNOPs, we found that the dominant amplitudes are located around (128°E, 17°N) horizontally and in the upper 1000 m vertically. For each event, the two CNOPs caused large prediction errors. Specifically, at the prediction time, CNOP1 (CNOP2) develops into an anticyclonic (cyclonic) eddy-like structure centered around 124°E, leading to the increase (decrease) of the upstream Kuroshio transport. By investigating the time evolution of the CNOPs in Event 1, we found that the eddy-like structures originating from east of Luzon gradually grow and simultaneously propagate westward. The eddy-energetic analysis indicated that the errors obtain energy from the background state through barotropic and baroclinic instabilities and that the latter plays a more important role. These results suggest that improving the initial conditions in east of Luzon could lead to better prediction of the upstream Kuroshio transport variation.

  3. Predictive medicine

    NARCIS (Netherlands)

    Boenink, Marianne; Have, ten Henk

    2015-01-01

    In the last part of the twentieth century, predictive medicine has gained currency as an important ideal in biomedical research and health care. Research in the genetic and molecular basis of disease suggested that the insights gained might be used to develop tests that predict the future health sta

  4. Predicting Macrosomia

    National Research Council Canada - National Science Library

    Pates, Jason A; McIntire, Donald D; Casey, Brian M; Leveno, Kenneth J

    2008-01-01

    Objective. The purpose of this study was to evaluate the prediction of fetal macrosomia based on ultrasound estimates of fetal weight and amniotic fluid volume combined with clinical risk factors. Methods...

  5. Using soft computing techniques to predict corrected air permeability using Thomeer parameters, air porosity and grain density

    Science.gov (United States)

    Nooruddin, Hasan A.; Anifowose, Fatai; Abdulraheem, Abdulazeez

    2014-03-01

    Soft computing techniques are recently becoming very popular in the oil industry. A number of computational intelligence-based predictive methods have been widely applied in the industry with high prediction capabilities. Some of the popular methods include feed-forward neural networks, radial basis function network, generalized regression neural network, functional networks, support vector regression and adaptive network fuzzy inference system. A comparative study among most popular soft computing techniques is presented using a large dataset published in literature describing multimodal pore systems in the Arab D formation. The inputs to the models are air porosity, grain density, and Thomeer parameters obtained using mercury injection capillary pressure profiles. Corrected air permeability is the target variable. Applying developed permeability models in recent reservoir characterization workflow ensures consistency between micro and macro scale information represented mainly by Thomeer parameters and absolute permeability. The dataset was divided into two parts with 80% of data used for training and 20% for testing. The target permeability variable was transformed to the logarithmic scale as a pre-processing step and to show better correlations with the input variables. Statistical and graphical analysis of the results including permeability cross-plots and detailed error measures were created. In general, the comparative study showed very close results among the developed models. The feed-forward neural network permeability model showed the lowest average relative error, average absolute relative error, standard deviations of error and root means squares making it the best model for such problems. Adaptive network fuzzy inference system also showed very good results.

  6. Dynamics and predictability of a low-order wind-driven ocean - atmosphere model

    Science.gov (United States)

    Vannitsem, Stéphane

    2013-04-01

    The dynamics of a low order coupled wind-driven Ocean-Atmosphere (OA) system is investigated with emphasis on its predictability properties. The low-order coupled deterministic system is composed of a baroclinic atmosphere for which 12 dominant dynamical modes are only retained (Charney and Straus, 1980) and a wind-driven, quasi-geostrophic and reduced-gravity shallow ocean whose field is truncated to four dominant modes able to reproduce the large scale oceanic gyres (Pierini, 2011). The two models are coupled through mechanical forcings only. The analysis of its dynamics reveals first that under aperiodic atmospheric forcings only dominant single gyres (clockwise or counterclockwise) appear. This feature is expected to be related with the specific domain choice over which the coupled system is defined. Second the dynamical quantities characterizing the short-term predictability (Lyapunov exponents, Lyapunov dimension, Kolmogorov-Sinaï (KS) entropy) displays a complex dependence as a function of the key parameters of the system, namely the coupling strength and the external thermal forcing. In particular, the KS-entropy is increasing as a function of the coupling in most of the experiments, implying an increase of the rate of loss of information about the localization of the system on his attractor. Finally the dynamics of the error is explored and indicates, in particular, a rich variety of short term behaviors of the error in the atmosphere depending on the (relative) amplitude of the initial error affecting the ocean, from polynomial (at2 + bt3 + ct4) up to purely exponential evolutions. These features are explained and analyzed in the light of the recent findings on error growth (Nicolis et al, 2009). References Charney J G, Straus DM (1980) Form-Drag Instability, Multiple Equilibria and Propagating Planetary Waves in Baroclinic, Orographically Forced, Planetary Wave Systems. J Atmos Sci 37: 1157-1176. Nicolis C, Perdigao RAP, Vannitsem S (2009) Dynamics of

  7. Prediction Markets

    DEFF Research Database (Denmark)

    Horn, Christian Franz; Ivens, Bjørn Sven; Ohneberg, Michael

    2014-01-01

    In recent years, Prediction Markets gained growing interest as a forecasting tool among researchers as well as practitioners, which resulted in an increasing number of publications. In order to track the latest development of research, comprising the extent and focus of research, this article...

  8. Inter-annual variability and long term predictability of exchanges through the Strait of Gibraltar

    Science.gov (United States)

    Boutov, Dmitri; Peliz, Álvaro; Miranda, Pedro M. A.; Soares, Pedro M. M.; Cardoso, Rita M.; Prieto, Laura; Ruiz, Javier; García-Lafuente, Jesus

    2014-03-01

    Inter-annual variability of calculated barotropic (netflow) and simulated baroclinic (inflow and outflow) exchanges through the Strait of Gibraltar is analyzed and their response to the main modes of atmospheric variability is investigated. Time series of the outflow obtained by high resolution simulations and estimated from in-situ Acoustic Doppler Current Profiler (ADCP) current measurements are compared. The time coefficients (TC) of the leading empirical orthogonal function (EOF) modes that describe zonal atmospheric circulation in the vicinity of the Strait (1st and 3rd of Sea-Level Pressure (SLP) and 1st of the wind) show significant covariance with the inflow and outflow. Based on these analyses, a regression model between these SLP TCs and outflow of the Mediterranean Water was developed. This regression outflow time series was compared with estimates based on current meter observations and the predictability and reconstruction of past exchange variability based on atmospheric pressure fields are discussed. The simple regression model seems to reproduce the outflow evolution fairly reasonably, with the exception of the year 2008, which is apparently anomalous without available physical explanation yet. The exchange time series show a reduced inter-annual variability (less than 1%, 2.6% and 3.1% of total 2-day variability, for netflow, inflow and outflow, respectively). From a statistical point of view no clear long-term tendencies were revealed. Anomalously high baroclinic fluxes are reported for the years of 2000-2001 that are coincident with strong impact on the Alboran Sea ecosystem. The origin of the anomalous flow is associated with a strong negative anomaly (~ - 9 hPa) in atmospheric pressure fields settled north of Iberian Peninsula and extending over the central Atlantic, favoring an increased zonal circulation in winter 2000/2001. These low pressure fields forced intense and durable westerly winds in the Gulf of Cadiz-Alboran system. The signal of

  9. A data-driven prediction method for fast-slow systems

    Science.gov (United States)

    Groth, Andreas; Chekroun, Mickael; Kondrashov, Dmitri; Ghil, Michael

    2016-04-01

    In this work, we present a prediction method for processes that exhibit a mixture of variability on low and fast scales. The method relies on combining empirical model reduction (EMR) with singular spectrum analysis (SSA). EMR is a data-driven methodology for constructing stochastic low-dimensional models that account for nonlinearity and serial correlation in the estimated noise, while SSA provides a decomposition of the complex dynamics into low-order components that capture spatio-temporal behavior on different time scales. Our study focuses on the data-driven modeling of partial observations from dynamical systems that exhibit power spectra with broad peaks. The main result in this talk is that the combination of SSA pre-filtering with EMR modeling improves, under certain circumstances, the modeling and prediction skill of such a system, as compared to a standard EMR prediction based on raw data. Specifically, it is the separation into "fast" and "slow" temporal scales by the SSA pre-filtering that achieves the improvement. We show, in particular that the resulting EMR-SSA emulators help predict intermittent behavior such as rapid transitions between specific regions of the system's phase space. This capability of the EMR-SSA prediction will be demonstrated on two low-dimensional models: the Rössler system and a Lotka-Volterra model for interspecies competition. In either case, the chaotic dynamics is produced through a Shilnikov-type mechanism and we argue that the latter seems to be an important ingredient for the good prediction skills of EMR-SSA emulators. Shilnikov-type behavior has been shown to arise in various complex geophysical fluid models, such as baroclinic quasi-geostrophic flows in the mid-latitude atmosphere and wind-driven double-gyre ocean circulation models. This pervasiveness of the Shilnikow mechanism of fast-slow transition opens interesting perspectives for the extension of the proposed EMR-SSA approach to more realistic situations.

  10. Predictable earthquakes?

    Science.gov (United States)

    Martini, D.

    2002-12-01

    acceleration) and global number of earthquake for this period from published literature which give us a great picture about the dynamical geophysical phenomena. Methodology: The computing of linear correlation coefficients gives us a chance to quantitatively characterise the relation among the data series, if we suppose a linear dependence in the first step. The correlation coefficients among the Earth's rotational acceleration and Z-orbit acceleration (perpendicular to the ecliptic plane) and the global number of the earthquakes were compared. The results clearly demonstrate the common feature of both the Earth's rotation and Earth's Z-acceleration around the Sun and also between the Earth's rotational acceleration and the earthquake number. This fact might means a strong relation among these phenomena. The mentioned rather strong correlation (r = 0.75) and the 29 year period (Saturn's synodic period) was clearly shown in the counted cross correlation function, which gives the dynamical characteristic of correlation, of Earth's orbital- (Z-direction) and rotational acceleration. This basic period (29 year) was also obvious in the earthquake number data sets with clear common features in time. Conclusion: The Core, which involves the secular variation of the Earth's magnetic field, is the only sufficiently mobile part of the Earth with a sufficient mass to modify the rotation which probably effects on the global time distribution of the earthquakes. Therefore it might means that the secular variation of the earthquakes is inseparable from the changes in Earth's magnetic field, i.e. the interior process of the Earth's core belongs to the dynamical state of the solar system. Therefore if the described idea is real the global distribution of the earthquakes in time is predictable.

  11. The dynamical integrity concept for interpreting/ predicting experimental behaviour: from macro- to nano-mechanics.

    Science.gov (United States)

    Lenci, Stefano; Rega, Giuseppe; Ruzziconi, Laura

    2013-06-28

    The dynamical integrity, a new concept proposed by J.M.T. Thompson, and developed by the authors, is used to interpret experimental results. After reviewing the main issues involved in this analysis, including the proposal of a new integrity measure able to capture in an easy way the safe part of basins, attention is dedicated to two experiments, a rotating pendulum and a micro-electro-mechanical system, where the theoretical predictions are not fulfilled. These mechanical systems, the former at the macro-scale and the latter at the micro-scale, permit a comparative analysis of different mechanical and dynamical behaviours. The fact that in both cases the dynamical integrity permits one to justify the difference between experimental and theoretical results, which is the main achievement of this paper, shows the effectiveness of this new approach and suggests its use in practical situations. The men of experiment are like the ant, they only collect and use; the reasoners resemble spiders, who make cobwebs out of their own substance. But the bee takes the middle course: it gathers its material from the flowers of the garden and field, but transforms and digests it by a power of its own. Not unlike this is the true business of philosophy (science); for it neither relies solely or chiefly on the powers of the mind, nor does it take the matter which it gathers from natural history and mechanical experiments and lay up in the memory whole, as it finds it, but lays it up in the understanding altered and digested. Therefore, from a closer and purer league between these two faculties, the experimental and the rational (such as has never been made), much may be hoped. (Francis Bacon 1561-1626) But are we sure of our observational facts? Scientific men are rather fond of saying pontifically that one ought to be quite sure of one's observational facts before embarking on theory. Fortunately those who give this advice do not practice what they preach. Observation and theory get

  12. On the predictivity of pore-scale simulations: Estimating uncertainties with multilevel Monte Carlo

    Science.gov (United States)

    Icardi, Matteo; Boccardo, Gianluca; Tempone, Raúl

    2016-09-01

    proposed method can be efficiently used in many porous media applications for problems such as stochastic homogenization/upscaling, propagation of uncertainty from microscopic fluid and rock properties to macro-scale parameters, robust estimation of Representative Elementary Volume size for arbitrary physics.

  13. On the predictivity of pore-scale simulations: estimating uncertainties with multilevel Monte Carlo

    KAUST Repository

    Icardi, Matteo

    2016-02-08

    , extrapolation and post-processing techniques. The proposed method can be efficiently used in many porous media applications for problems such as stochastic homogenization/upscaling, propagation of uncertainty from microscopic fluid and rock properties to macro-scale parameters, robust estimation of Representative Elementary Volume size for arbitrary physics.

  14. Interconnecting Urban Planning with Multi-Scale Urban Quality: Review of Macro Scale Urban Redevelopment Project on Micro Scale Urban Quality in Shenzhen

    NARCIS (Netherlands)

    Deng, X.

    2015-01-01

    The Shenzhen planning system has been effective in promoting economic growth through the prodigious urbanization of land. It has given priority to the ‘macro-level’ planning goals of economic growth through physical development. Questions can be raised about the physical and social outcomes from the

  15. Simulation and experimental determination of the macro-scale layer thickness distribution of electrodeposited Cu-line patterns on a wafer substrate

    DEFF Research Database (Denmark)

    Pantleon, Karen; Bossche, Bart van den; Purcar, Marius

    2005-01-01

    The impact of adjacent patterned zones with different active area densities on the current density and electrodeposited layer thickness distribution over a wafer substrate is examined, both by experiment and numerical simulation. The experiments consist in running an acid copper plating process......) approach to compute the current density distribution over the electrodes. Experimental and computed layer thickness distributions are in very good agreement....

  16. Interconnecting Urban Planning with Multi-Scale Urban Quality: Review of Macro Scale Urban Redevelopment Project on Micro Scale Urban Quality in Shenzhen

    OpenAIRE

    Deng, X.

    2015-01-01

    The Shenzhen planning system has been effective in promoting economic growth through the prodigious urbanization of land. It has given priority to the ‘macro-level’ planning goals of economic growth through physical development. Questions can be raised about the physical and social outcomes from the development process at the ‘micro-level’, not least in the level of ‘quality’ of the physical environment at the micro scale and the creation of a ‘place identity’ (Chen, 2010; Hang, 2006; Wu, 201...

  17. Interconnecting Urban Planning with Multi-Scale Urban Quality: Review of Macro Scale Urban Redevelopment Project on Micro Scale Urban Quality in Shenzhen

    NARCIS (Netherlands)

    Deng, X.

    2015-01-01

    The Shenzhen planning system has been effective in promoting economic growth through the prodigious urbanization of land. It has given priority to the ‘macro-level’ planning goals of economic growth through physical development. Questions can be raised about the physical and social outcomes from the

  18. Macro-scale assessment of demographic and environmental variation within genetically derived evolutionary lineages of eastern hemlock (Tsuga canadensis), an imperiled conifer of the eastern United States

    Science.gov (United States)

    Anantha M. Prasad; Kevin M. Potter

    2017-01-01

    Eastern hemlock (Tsuga canadensis) occupies a large swath of eastern North America and has historically undergone range expansion and contraction resulting in several genetically separate lineages. This conifer is currently experiencing mortality across most of its range following infestation of a non-native insect. With the goal of better...

  19. Simulation and experimental determination of the macro-scale layer thickness distribution of electrodeposited Cu-line patterns on a wafer substrate

    DEFF Research Database (Denmark)

    Pantleon, Karen; Bossche, Bart van den; Purcar, Marius;

    2005-01-01

    The impact of adjacent patterned zones with different active area densities on the current density and electrodeposited layer thickness distribution over a wafer substrate is examined, both by experiment and numerical simulation. The experiments consist in running an acid copper plating process...... on the patterned wafer, and layer thickness measurements by means of X-ray fluorescence (XRF) and atomic force microscopy (AFM). The simulations are based on a potential model approach taking into account electrolyte ohmic drop and electrode polarization effects, combined to a boundary element method (BEM......) approach to compute the current density distribution over the electrodes. Experimental and computed layer thickness distributions are in very good agreement....

  20. Remote sensing based evapotranspiration and runoff modeling of agricultural, forest and urban flux sites in Denmark: From field to macro-scale

    DEFF Research Database (Denmark)

    Bøgh, E.; Poulsen, R.N.; Butts, M.

    2009-01-01

    and most sensitive to the spatial land surface representation. A good agreement was observed in the timing and size of peak flows in catchment dominated by agricultural, forest and urban land uses in periods when E has important control on the water balance and soil water percolation to groundwater...... E modeling, (3) high accuracy remote sensing based estimation of vegetation parameters is particularly important during sparsely vegetated conditions, and (4) the use of component stream flow data to evaluate the physical consistency of spatial-deterministic models appears to be feasible and should...

  1. Design of periodic nano- and macro-scale textures for high-performance thin-film multi-junction solar cells

    Science.gov (United States)

    Krc, J.; Sever, M.; Kovacic, M.; Moulin, E.; Campa, A.; Lipovsek, B.; Steltenpool, M.; van Erven, A. J. M.; Haug, F.-J.; Ballif, C.; Topic, M.

    2016-06-01

    Surface textures in thin-film silicon multi-junction solar cells play an important role in gaining the photocurrent of the devices. In this paper, a design of the textures is carried out for the case of amorphous silicon/micro-crystalline silicon (a-Si:H/μc-Si:H) solar cells, employing advanced modelling to determine the textures for defect-free silicon layer growth and to increase the photocurrent. A model of non-conformal layer growth and a hybrid optical modelling approach are used to perform realistic 3D simulations of the structures. The hybrid optical modelling includes rigorous modelling based on the finite element method and geometrical optics models. This enables us to examine the surface texture scaling from nano- to macro-sized (several tens or hundreds of micrometers) texturisation features. First, selected random and periodic nanotextures are examined with respect to critical positions of defect-region formation in Si layers. We show that despite careful selection of a well-suited semi-ellipsoidal periodic texture for defect-free layer growth, defective regions in Si layers of a-Si:H/μc-Si:H cell cannot be avoided if the lateral and vertical dimensions of the nano features are optimised only for high gain in photocurrent. Macro features are favourable for defect-free layer growth, but do not render the photocurrent gains as achieved with light-scattering properties of the optimised nanotextures. Simulation results show that from the optical point of view the semi-ellipsoidal periodic nanotextures with lateral features smaller than 0.4 μm and vertical peak-to-peak heights around or above 0.3 μm are required to achieve a gain in short-circuit current of the top cell with respect to the state-of-the-art random texture (>16% increase), whereas lateral dimensions around 0.8 μm and heights around 0.6 μm lead to a >6% gain in short-circuit current of the bottom cell.

  2. Land Market Interactions between Heterogeneous Agents in a Heterogeneous Landscape—Tracing the Macro-Scale Effects of Individual Trade-Offs between Environmental Amenities and Disamenities

    NARCIS (Netherlands)

    Filatova, Tatiana; Veen, van der Anne; Parker, Dawn C.

    2009-01-01

    Heterogeneity in both the spatial environment and economic agents is a crucial driver of land market dynamics. We present an agent-based land market model where land from agriculture use is transferred into urban. The model combines the microeconomic demand, supply, and bidding foundations of spatia

  3. Making detailed predictions makes (some) predictions worse

    Science.gov (United States)

    Kelly, Theresa F.

    In this paper, we investigate whether making detailed predictions about an event makes other predictions worse. Across 19 experiments, 10,895 participants, and 415,960 predictions about 724 professional sports games, we find that people who made detailed predictions about sporting events (e.g., how many hits each baseball team would get) made worse predictions about more general outcomes (e.g., which team would win). We rule out that this effect is caused by inattention or fatigue, thinking too hard, or a differential reliance on holistic information about the teams. Instead, we find that thinking about game-relevant details before predicting winning teams causes people to give less weight to predictive information, presumably because predicting details makes information that is relatively useless for predicting the winning team more readily accessible in memory and therefore incorporated into forecasts. Furthermore, we show that this differential use of information can be used to predict what kinds of games will and will not be susceptible to the negative effect of making detailed predictions.

  4. Fully Implicit Numerical Methods for the Baroclinic Primitive Equations

    Science.gov (United States)

    Cohn, S. E.; Isaacson, E.

    1984-01-01

    A fully implicit code was developed to solve the three-dimensional primitive equations of atmospheric flow. The scheme is second order accurate in time and fourth order accurate in the horizontal and vertical directions. Furthermore, as a result of being fully implicit, the time step is not restricted by the mesh spacing near the poles, nor by the speed of inertia-gravity waves. Rather, the time step, deltat is determined simply by the requirement that it be small enough to adequately resolve the atmospheric flow of interest. The accuracy and efficiency of current models for fine grids should be significantly improved.

  5. Internal wave emission from baroclinic jets: experimental results

    Science.gov (United States)

    Borcia, Ion D.; Rodda, Costanza; Harlander, Uwe

    2016-04-01

    Large-scale balanced flows can spontaneously radiate meso-scale inertia-gravity waves (IGWs) and are thus in fact unbalanced. While flow-dependent parameterizations for the radiation of IGWs from orographic and convective sources do exist, the situation is less developed for spontaneously emitted IGWs. Observations identify increased IGW activity in the vicinity of jet exit regions. A direct interpretation of those based on geostrophic adjustment might be tempting. However, directly applying this concept to the parameterization of spontaneous imbalance is difficult since the dynamics itself is continuously re-establishing an unbalanced flow which then sheds imbalances by GW radiation. Examining spontaneous IGW emission in the atmosphere and validating parameterization schemes confronts the scientist with particular challenges. Due to its extreme complexity, GW emission will always be embedded in the interaction of a multitude of interdependent processes, many of which are hardly detectable from analysis or campaign data. The benefits of repeated and more detailed measurements, while representing the only source of information about the real atmosphere, are limited by the non-repeatability of an atmospheric situation. The same event never occurs twice. This argues for complementary laboratory experiments, which can provide a more focused dialogue between experiment and theory. Indeed, life cycles are also examined in rotating-annulus laboratory experiments. Thus, these experiments might form a useful empirical benchmark for theoretical and modeling work that is also independent of any sort of subgrid model. In addition, the more direct correspondence between experimental and model data and the data reproducibility makes lab experiments a powerful testbed for parameterizations. Here we show first results from a small rotating annulus experiments and we will further present our new experimental facility to study wave emission from jets and fronts.

  6. Hysteresis and Wavenumber Vacillation in Unstable Baroclinic Flows

    Science.gov (United States)

    Chou, Shih-Hung; Goodman, H. Michael (Technical Monitor)

    2001-01-01

    Hysteresis and wavenumber vacillation are studied numerically in a weakly stratified quasigeostrophic model. In general, the amplitude of the most unstable wave increases, as the flow becomes more unstable. When the wave becomes saturated, the next longer wave will grow at the expanse of the most unstable wave and becomes the dominant wave. However, once the longwave state is established, it may remain in that regime even as the instability is decreased beyond the threshold where it first developed, thus constituting a hysteresis loop. In a highly unstable case, the flow may not show a preference for any single wave. Instead, the dominant wave aperiodically varies among several long waves. This phenomenon is known as wavenumber vacillation. Hysteresis is further examined in terms of eddy heat flux. It is shown that total eddy heat flux increases as the flow becomes more unstable, but displays a sharp drop when transition to a longer wave occurs. However, in a longwave state, the heat flux always decreases with decreasing instability even pass the threshold when wave transition first occurs.

  7. The convective stability of fully stratified baroclinic discs

    CERN Document Server

    Volponi, Francesco

    2016-01-01

    We examine the convective stability of hydrodynamic discs with full stratification in the local approximation and in the presence of thermal diffusion (or relaxation). Various branches of the relevant axisymmetric dispersion relation derived by Urpin (2003) are discussed. We find that when the vertical Richardson number is larger than or equal to the radial one (i.e. $|Ri_z|\\geq|Ri_x|$) and wavenumbers are comparable (i.e. $|k_x|\\sim|k_z|$) the disc becomes unstable, even in the presence of radial and vertical stratifications with $Ri_x>0$ and $Ri_z>0$. The origin of this resides in an hybrid radial-vertical Richardson number. We propose an equilibrium profile with temperature depending on the radial and vertical coordinates and with $Ri_z>0$ for which this destabilization mechanism occurs. We notice as well that the dispersion relation of the "convective overstability" is the branch of the one here discussed in the limit $|k_z|\\gg|k_x|$ (i. e. two-dimensional disc).

  8. Wind-induced baroclinic response of Lake Constance

    Directory of Open Access Journals (Sweden)

    Y. Wang

    Full Text Available We present results of various circulation scenarios for the wind-induced three-dimensional currents in Lake Constance, obtained with the aid of a semi-spectral semi-implicit finite difference code developed in Haidvogel et al. and Wang and Hutter. Internal Kelvin and Poincaré-type oscillations are demonstrated in the numerical results, whose periods depend upon the stratification and the geometry of the basin and agree well with measured data. By solving the eigenvalue problem of the linearized shallow water equations in the two-layered stratified Lake Constance, the interpretation of the oscillations as Kelvin and Poincaré-type waves is corroborated.

    Key words: Oceanography: general (limnology; numerical modeling – Oceanography: physical (internal and inertial waves

  9. The Impact of Horizontal Resolution on the CNOP and on Its Identified Sensitive Areas for Tropical Cyclone Predictions

    Institute of Scientific and Technical Information of China (English)

    ZHOU Feifan; MU Mu

    2012-01-01

    In this study,the impacts of horizontal resolution on the conditional nonlinear optimal perturbation (CNOP) and on its identified sensitive areas were investigated for tropical cyclone predictions.Three resolutions,30 km,60 km,and 120 km,were studied for three tropical cyclones,TC Mindulle (2004),TC Meari (2004),and TC Matsa (2005).Results show that CNOP may present different structures with different resolutions,and the major parts of CNOP become increasingly localized with increased horizontal resolution.CNOP produces spiral and baroclinic structures,which partially account for its rapid amplification.The differences in CNOP structures result in different sensitive areas,but there are common areas for the CNOP-identified sensitive areas at various resolutions,and the size of the common areas is different from case to case.Generally,the forecasts benefit more from the reduction of the initial errors in the sensitive areas identified using higher resolutions than those using lower resolutions.However,the largest improvement of the forecast can be obtained at the resolution that is not the highest for some cases.In addition,the sensitive areas identified at lower resolutions are also helpful for improving the forecast with a finer resolution,but the sensitive areas identified at the same resolution as the forecast would be the most beneficial.

  10. Predicting outdoor sound

    CERN Document Server

    Attenborough, Keith; Horoshenkov, Kirill

    2014-01-01

    1. Introduction  2. The Propagation of Sound Near Ground Surfaces in a Homogeneous Medium  3. Predicting the Acoustical Properties of Outdoor Ground Surfaces  4. Measurements of the Acoustical Properties of Ground Surfaces and Comparisons with Models  5. Predicting Effects of Source Characteristics on Outdoor Sound  6. Predictions, Approximations and Empirical Results for Ground Effect Excluding Meteorological Effects  7. Influence of Source Motion on Ground Effect and Diffraction  8. Predicting Effects of Mixed Impedance Ground  9. Predicting the Performance of Outdoor Noise Barriers  10. Predicting Effects of Vegetation, Trees and Turbulence  11. Analytical Approximations including Ground Effect, Refraction and Turbulence  12. Prediction Schemes  13. Predicting Sound in an Urban Environment.

  11. A Multiphysics Framework to Learn and Predict in Presence of Multiple Scales

    Science.gov (United States)

    Tomin, P.; Lunati, I.

    2015-12-01

    Modeling complex phenomena in the subsurface remains challenging due to the presence of multiple interacting scales, which can make it impossible to focus on purely macroscopic phenomena (relevant in most applications) and neglect the processes at the micro-scale. We present and discuss a general framework that allows us to deal with the situation in which the lack of scale separation requires the combined use of different descriptions at different scale (for instance, a pore-scale description at the micro-scale and a Darcy-like description at the macro-scale) [1,2]. The method is based on conservation principles and constructs the macro-scale problem by numerical averaging of micro-scale balance equations. By employing spatiotemporal adaptive strategies, this approach can efficiently solve large-scale problems [2,3]. In addition, being based on a numerical volume-averaging paradigm, it offers a tool to illuminate how macroscopic equations emerge from microscopic processes, to better understand the meaning of microscopic quantities, and to investigate the validity of the assumptions routinely used to construct the macro-scale problems. [1] Tomin, P., and I. Lunati, A Hybrid Multiscale Method for Two-Phase Flow in Porous Media, Journal of Computational Physics, 250, 293-307, 2013 [2] Tomin, P., and I. Lunati, Local-global splitting and spatiotemporal-adaptive Multiscale Finite Volume Method, Journal of Computational Physics, 280, 214-231, 2015 [3] Tomin, P., and I. Lunati, Spatiotemporal adaptive multiphysics simulations of drainage-imbibition cycles, Computational Geosciences, 2015 (under review)

  12. Genomic Prediction in Barley

    DEFF Research Database (Denmark)

    Edriss, Vahid; Cericola, Fabio; Jensen, Jens D;

    Genomic prediction uses markers (SNPs) across the whole genome to predict individual breeding values at an early growth stage potentially before large scale phenotyping. One of the applications of genomic prediction in plant breeding is to identify the best individual candidate lines to contribut...

  13. Genomic Prediction in Barley

    DEFF Research Database (Denmark)

    Edriss, Vahid; Cericola, Fabio; Jensen, Jens D;

    2015-01-01

    Genomic prediction uses markers (SNPs) across the whole genome to predict individual breeding values at an early growth stage potentially before large scale phenotyping. One of the applications of genomic prediction in plant breeding is to identify the best individual candidate lines to contribut...

  14. Introduction of the NWP Model Development Project at Korea Institute of Atmospheric Prediction Systems - KIAPS

    Science.gov (United States)

    Kim, Y.

    2012-12-01

    Korea Meteorological Administration (KMA) launched a 9-year project in 2011 to develop Korea's own global NWP system with the total funding of about 100 million US dollars. To lead the effort, Korea Institute of Atmospheric Prediction Systems (KIAPS) was founded by KMA as a non-profit foundation. The project consists of three stages. We are in the middle of the first stage (2011-2013), which is to set up the Institute, recruit researchers, lay out plans for the research and development, and design the basic structure and explore/develop core NWP technologies. The second stage (2014-2016) aims at developing the modules for the dynamical core, physical parameterizations and data assimilation systems as well as the system framework and couplers to connect the modules in a systematic and efficient way, and eventually building a prototype NWP system. The third stage (2017-2019) is for evaluating the prototype system by selecting/improving modules, and refining/finalizing it for operational use at KMA as well as developing necessary post-processing systems. In 2012, we are designing key modules for the dynamical core by adopting existing and/or developing new cores, and developing the barographic model first and the baroclinic model later with code parallelization and optimization in mind. We are collecting various physical parameterization schemes, mostly developed by Korean scientists, and evaluating and improving them by using single-column and LES models, etc. We are designing control variables for variational data assimilation systems, constructing testbeds for observational data pre-processing systems, developing linear models for a barographic system, designing modules for cost function minimization. We are developing the module framework, which is flexible for prognostic and diagnostic variables, designing the I/O structure of the system, coupling modules for external systems, and also developing post-processing systems. At the meeting, we will present the

  15. Applied predictive control

    CERN Document Server

    Sunan, Huang; Heng, Lee Tong

    2002-01-01

    The presence of considerable time delays in the dynamics of many industrial processes, leading to difficult problems in the associated closed-loop control systems, is a well-recognized phenomenon. The performance achievable in conventional feedback control systems can be significantly degraded if an industrial process has a relatively large time delay compared with the dominant time constant. Under these circumstances, advanced predictive control is necessary to improve the performance of the control system significantly. The book is a focused treatment of the subject matter, including the fundamentals and some state-of-the-art developments in the field of predictive control. Three main schemes for advanced predictive control are addressed in this book: • Smith Predictive Control; • Generalised Predictive Control; • a form of predictive control based on Finite Spectrum Assignment. A substantial part of the book addresses application issues in predictive control, providing several interesting case studie...

  16. Predicting Predictable about Natural Catastrophic Extremes

    Science.gov (United States)

    Kossobokov, Vladimir

    2015-04-01

    By definition, an extreme event is rare one in a series of kindred phenomena. Usually (e.g. in Geophysics), it implies investigating a small sample of case-histories with a help of delicate statistical methods and data of different quality, collected in various conditions. Many extreme events are clustered (far from independent) and follow fractal or some other "strange" distribution (far from uniform). Evidently, such an "unusual" situation complicates search and definition of reliable precursory behaviors to be used for forecast/prediction purposes. Making forecast/prediction claims reliable and quantitatively probabilistic in the frames of the most popular objectivists' viewpoint on probability requires a long series of "yes/no" forecast/prediction outcomes, which cannot be obtained without an extended rigorous test of the candidate method. The set of errors ("success/failure" scores and space-time measure of alarms) and other information obtained in such a control test supplies us with data necessary to judge the candidate's potential as a forecast/prediction tool and, eventually, to find its improvements. This is to be done first in comparison against random guessing, which results confidence (measured in terms of statistical significance). Note that an application of the forecast/prediction tools could be very different in cases of different natural hazards, costs and benefits that determine risks, and, therefore, requires determination of different optimal strategies minimizing reliable estimates of realistic levels of accepted losses. In their turn case specific costs and benefits may suggest a modification of the forecast/prediction tools for a more adequate "optimal" application. Fortunately, the situation is not hopeless due to the state-of-the-art understanding of the complexity and non-linear dynamics of the Earth as a Physical System and pattern recognition approaches applied to available geophysical evidences, specifically, when intending to predict

  17. Formal derivation of a 6 equation macro scale model for two-phase flows - link with the 4 equation macro scale model implemented in Flica 4; Etablissement formel d'un modele diphasique macroscopique a 6 equations - lien avec le modele macroscopique a 4 equations flica 4

    Energy Technology Data Exchange (ETDEWEB)

    Gregoire, O

    2008-07-01

    In order to simulate nuclear reactor cores, we presently use the 4 equation model implemented within FLICA4 code. This model is complemented with 2 algebraic closures for thermal disequilibrium and relative velocity between phases. Using such closures, means an 'a priori' knowledge of flows calculated in order to ensure that modelling assumptions apply. In order to improve the degree of universality to our macroscopic modelling, we propose in the report to derive a more general 6 equation model (balance equations for mass, momentum and enthalpy for each phase) for 2-phase flows. We apply the up-scaling procedure (Whitaker, 1999) classically used in porous media analysis to the statistically averaged equations (Aniel-Buchheit et al., 2003). By doing this, we apply the double-averaging procedure (Pedras and De Lemos, 2001 and Pinson et al. 2006): statistical and spatial averages. Then, using weighted averages (analogous to Favre's average) we extend the spatial averaging concept to variable density and 2-phase flows. This approach allows the global recovering of the structure of the systems of equations implemented in industrial codes. Supplementary contributions, such as dispersion, are also highlighted. Mechanical and thermal exchanges between solids and fluid are formally derived. Then, thanks to realistic simplifying assumptions, we show how it is possible to derive the original 4 equation model from the full 6 equation model. (author)

  18. Predictive systems ecology.

    Science.gov (United States)

    Evans, Matthew R; Bithell, Mike; Cornell, Stephen J; Dall, Sasha R X; Díaz, Sandra; Emmott, Stephen; Ernande, Bruno; Grimm, Volker; Hodgson, David J; Lewis, Simon L; Mace, Georgina M; Morecroft, Michael; Moustakas, Aristides; Murphy, Eugene; Newbold, Tim; Norris, K J; Petchey, Owen; Smith, Matthew; Travis, Justin M J; Benton, Tim G

    2013-11-22

    Human societies, and their well-being, depend to a significant extent on the state of the ecosystems that surround them. These ecosystems are changing rapidly usually in response to anthropogenic changes in the environment. To determine the likely impact of environmental change on ecosystems and the best ways to manage them, it would be desirable to be able to predict their future states. We present a proposal to develop the paradigm of predictive systems ecology, explicitly to understand and predict the properties and behaviour of ecological systems. We discuss the necessary and desirable features of predictive systems ecology models. There are places where predictive systems ecology is already being practised and we summarize a range of terrestrial and marine examples. Significant challenges remain but we suggest that ecology would benefit both as a scientific discipline and increase its impact in society if it were to embrace the need to become more predictive.

  19. Predictability of conversation partners

    CERN Document Server

    Takaguchi, Taro; Sato, Nobuo; Yano, Kazuo; Masuda, Naoki

    2011-01-01

    Recent developments in sensing technologies have enabled us to examine the nature of human social behavior in greater detail. By applying an information theoretic method to the spatiotemporal data of cell-phone locations, Song et al. (2010) found that human mobility patterns are remarkably predictable. Inspired by their work, we address a similar predictability question in a different kind of human social activity: conversation events. The predictability in the sequence of one's conversation partners is defined as the degree to which one's next conversation partner can be predicted given the current partner. We quantify this predictability by using the mutual information. We examine the predictability of conversation events for each individual using the longitudinal data of face-to-face interactions collected from two company offices in Japan. Each subject wears a name tag equipped with an infrared sensor node, and conversation events are marked when signals are exchanged between close sensor nodes. We find t...

  20. Distribution Free Prediction Bands

    CERN Document Server

    Lei, Jing

    2012-01-01

    We study distribution free, nonparametric prediction bands with a special focus on their finite sample behavior. First we investigate and develop different notions of finite sample coverage guarantees. Then we give a new prediction band estimator by combining the idea of "conformal prediction" (Vovk et al. 2009) with nonparametric conditional density estimation. The proposed estimator, called COPS (Conformal Optimized Prediction Set), always has finite sample guarantee in a stronger sense than the original conformal prediction estimator. Under regularity conditions the estimator converges to an oracle band at a minimax optimal rate. A fast approximation algorithm and a data driven method for selecting the bandwidth are developed. The method is illustrated first in simulated data. Then, an application shows that the proposed method gives desirable prediction intervals in an automatic way, as compared to the classical linear regression modeling.

  1. Predictability of Conversation Partners

    Science.gov (United States)

    Takaguchi, Taro; Nakamura, Mitsuhiro; Sato, Nobuo; Yano, Kazuo; Masuda, Naoki

    2011-08-01

    Recent developments in sensing technologies have enabled us to examine the nature of human social behavior in greater detail. By applying an information-theoretic method to the spatiotemporal data of cell-phone locations, [C. Song , ScienceSCIEAS0036-8075 327, 1018 (2010)] found that human mobility patterns are remarkably predictable. Inspired by their work, we address a similar predictability question in a different kind of human social activity: conversation events. The predictability in the sequence of one’s conversation partners is defined as the degree to which one’s next conversation partner can be predicted given the current partner. We quantify this predictability by using the mutual information. We examine the predictability of conversation events for each individual using the longitudinal data of face-to-face interactions collected from two company offices in Japan. Each subject wears a name tag equipped with an infrared sensor node, and conversation events are marked when signals are exchanged between sensor nodes in close proximity. We find that the conversation events are predictable to a certain extent; knowing the current partner decreases the uncertainty about the next partner by 28.4% on average. Much of the predictability is explained by long-tailed distributions of interevent intervals. However, a predictability also exists in the data, apart from the contribution of their long-tailed nature. In addition, an individual’s predictability is correlated with the position of the individual in the static social network derived from the data. Individuals confined in a community—in the sense of an abundance of surrounding triangles—tend to have low predictability, and those bridging different communities tend to have high predictability.

  2. Solar Cycle Predictions

    Science.gov (United States)

    Pesnell, William Dean

    2012-01-01

    Solar cycle predictions are needed to plan long-term space missions; just like weather predictions are needed to plan the launch. Fleets of satellites circle the Earth collecting many types of science data, protecting astronauts, and relaying information. All of these satellites are sensitive at some level to solar cycle effects. Predictions of drag on LEO spacecraft are one of the most important. Launching a satellite with less propellant can mean a higher orbit, but unanticipated solar activity and increased drag can make that a Pyrrhic victory as you consume the reduced propellant load more rapidly. Energetic events at the Sun can produce crippling radiation storms that endanger all assets in space. Solar cycle predictions also anticipate the shortwave emissions that cause degradation of solar panels. Testing solar dynamo theories by quantitative predictions of what will happen in 5-20 years is the next arena for solar cycle predictions. A summary and analysis of 75 predictions of the amplitude of the upcoming Solar Cycle 24 is presented. The current state of solar cycle predictions and some anticipations how those predictions could be made more accurate in the future will be discussed.

  3. Genomic Prediction in Barley

    DEFF Research Database (Denmark)

    Edriss, Vahid; Cericola, Fabio; Jensen, Jens D

    2015-01-01

    Genomic prediction uses markers (SNPs) across the whole genome to predict individual breeding values at an early growth stage potentially before large scale phenotyping. One of the applications of genomic prediction in plant breeding is to identify the best individual candidate lines to contribute...... to next generation. The main goal of this study was to see the potential of using genomic prediction in a commercial Barley breeding program. The data used in this study was from Nordic Seed company which is located in Denmark. Around 350 advanced lines were genotyped with 9K Barely chip from Illumina...

  4. Is Time Predictability Quantifiable?

    DEFF Research Database (Denmark)

    Schoeberl, Martin

    2012-01-01

    -case execution time. To compare different approaches we would like to quantify time predictability. That means we need to measure time predictability. In this paper we discuss the different approaches for these measurements and conclude that time predictability is practically not quantifiable. We can only......Computer architects and researchers in the realtime domain start to investigate processors and architectures optimized for real-time systems. Optimized for real-time systems means time predictable, i.e., architectures where it is possible to statically derive a tight bound of the worst...... compare the worst-case execution time bounds of different architectures....

  5. Predicting AD conversion

    DEFF Research Database (Denmark)

    Liu, Yawu; Mattila, Jussi; Ruiz, Miguel �ngel Mu�oz

    2013-01-01

    To compare the accuracies of predicting AD conversion by using a decision support system (PredictAD tool) and current research criteria of prodromal AD as identified by combinations of episodic memory impairment of hippocampal type and visual assessment of medial temporal lobe atrophy (MTA) on MRI...

  6. Predicting the MJO

    Science.gov (United States)

    Hendon, H.

    2003-04-01

    Extended range prediction of the Madden Julian Oscillation (MJO) and seasonal prediction of MJO activity are reviewed. Skillful prediction of individual MJO events offers the possibility of forecasting increased risk of cyclone development throughout the global tropics, altered risk of extreme rainfall events in both tropics and extratropics, and displacement of storm tracks with 3-4 week lead times. The level of MJO activity within a season, which affects the mean intensity of the Australian summer monsoon and possibly the evolution of ENSO, may be governed by variations of sea surface temperature that are predictable with lead times of a few seasons. The limit of predictability for individual MJO events is unknown. Empirical-statistical schemes are skillful out to about 3 weeks and have better skill than dynamical forecast models at lead times longer than about 5 days. The dynamical forecast models typically suffer from a poor representation (or complete lack) of the MJO and large initial error. They are better used to ascertain the global impacts of the lack of the MJO rather than for determination of the limit of predictability. Dynamical extended range prediction within a GCM that has a good representation of the MJO indicates potential skill comparable to the empirical schemes. Examples of operational extended range prediction with POAMA, the new coupled seasonal forecast model at the Bureau of Meteorology that also reasonably simulates the MJO, will be presented.

  7. Protein Sorting Prediction

    DEFF Research Database (Denmark)

    Nielsen, Henrik

    2017-01-01

    Many computational methods are available for predicting protein sorting in bacteria. When comparing them, it is important to know that they can be grouped into three fundamentally different approaches: signal-based, global-property-based and homology-based prediction. In this chapter, the strengths...

  8. Improved nonlinear prediction method

    Science.gov (United States)

    Adenan, Nur Hamiza; Md Noorani, Mohd Salmi

    2014-06-01

    The analysis and prediction of time series data have been addressed by researchers. Many techniques have been developed to be applied in various areas, such as weather forecasting, financial markets and hydrological phenomena involving data that are contaminated by noise. Therefore, various techniques to improve the method have been introduced to analyze and predict time series data. In respect of the importance of analysis and the accuracy of the prediction result, a study was undertaken to test the effectiveness of the improved nonlinear prediction method for data that contain noise. The improved nonlinear prediction method involves the formation of composite serial data based on the successive differences of the time series. Then, the phase space reconstruction was performed on the composite data (one-dimensional) to reconstruct a number of space dimensions. Finally the local linear approximation method was employed to make a prediction based on the phase space. This improved method was tested with data series Logistics that contain 0%, 5%, 10%, 20% and 30% of noise. The results show that by using the improved method, the predictions were found to be in close agreement with the observed ones. The correlation coefficient was close to one when the improved method was applied on data with up to 10% noise. Thus, an improvement to analyze data with noise without involving any noise reduction method was introduced to predict the time series data.

  9. Seismology for rockburst prediction.

    CSIR Research Space (South Africa)

    De Beer, W

    2000-02-01

    Full Text Available . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.1.3 Establish the predictive power, applicability and efficiency for each model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 3.1.3.1 Non-parametric statistics... . . . . . . . . . . . . . . . . . . . . . . . . 9 3.1.3.2 Time to failure prediction algorithm . . . . . . . . . . . . . . . 9 3.1.4 Testing for deterministic components of time series of interest, noise reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3...

  10. The Prediction Value

    NARCIS (Netherlands)

    Koster, M.; Kurz, S.; Lindner, I.; Napel, S.

    2013-01-01

    We introduce the prediction value (PV) as a measure of players’ informational importance in probabilistic TU games. The latter combine a standard TU game and a probability distribution over the set of coalitions. Player i’s prediction value equals the difference between the conditional expectations

  11. Predicting protein structure classes from function predictions

    DEFF Research Database (Denmark)

    Sommer, I.; Rahnenfuhrer, J.; de Lichtenberg, Ulrik;

    2004-01-01

    We introduce a new approach to using the information contained in sequence-to-function prediction data in order to recognize protein template classes, a critical step in predicting protein structure. The data on which our method is based comprise probabilities of functional categories; for given...... query sequences these probabilities are obtained by a neural net that has previously been trained on a variety of functionally important features. On a training set of sequences we assess the relevance of individual functional categories for identifying a given structural family. Using a combination...... of the most relevant categories, the likelihood of a query sequence to belong to a specific family can be estimated. Results: The performance of the method is evaluated using cross-validation. For a fixed structural family and for every sequence, a score is calculated that measures the evidence for family...

  12. Improving Prediction Skill of Imperfect Turbulent Models Through Statistical Response and Information Theory

    Science.gov (United States)

    Majda, Andrew J.; Qi, Di

    2016-02-01

    Turbulent dynamical systems with a large phase space and a high degree of instabilities are ubiquitous in climate science and engineering applications. Statistical uncertainty quantification (UQ) to the response to the change in forcing or uncertain initial data in such complex turbulent systems requires the use of imperfect models due to the lack of both physical understanding and the overwhelming computational demands of Monte Carlo simulation with a large-dimensional phase space. Thus, the systematic development of reduced low-order imperfect statistical models for UQ in turbulent dynamical systems is a grand challenge. This paper applies a recent mathematical strategy for calibrating imperfect models in a training phase and accurately predicting the response by combining information theory and linear statistical response theory in a systematic fashion. A systematic hierarchy of simple statistical imperfect closure schemes for UQ for these problems is designed and tested which are built through new local and global statistical energy conservation principles combined with statistical equilibrium fidelity. The forty mode Lorenz 96 (L-96) model which mimics forced baroclinic turbulence is utilized as a test bed for the calibration and predicting phases for the hierarchy of computationally cheap imperfect closure models both in the full phase space and in a reduced three-dimensional subspace containing the most energetic modes. In all of phase spaces, the nonlinear response of the true model is captured accurately for the mean and variance by the systematic closure model, while alternative methods based on the fluctuation-dissipation theorem alone are much less accurate. For reduced-order model for UQ in the three-dimensional subspace for L-96, the systematic low-order imperfect closure models coupled with the training strategy provide the highest predictive skill over other existing methods for general forced response yet have simple design principles based on a

  13. Prediction by Compression

    CERN Document Server

    Ratsaby, Joel

    2010-01-01

    It is well known that text compression can be achieved by predicting the next symbol in the stream of text data based on the history seen up to the current symbol. The better the prediction the more skewed the conditional probability distribution of the next symbol and the shorter the codeword that needs to be assigned to represent this next symbol. What about the opposite direction ? suppose we have a black box that can compress text stream. Can it be used to predict the next symbol in the stream ? We introduce a criterion based on the length of the compressed data and use it to predict the next symbol. We examine empirically the prediction error rate and its dependency on some compression parameters.

  14. Structural prediction in aphasia

    Directory of Open Access Journals (Sweden)

    Tessa Warren

    2015-05-01

    Full Text Available There is considerable evidence that young healthy comprehenders predict the structure of upcoming material, and that their processing is facilitated when they encounter material matching those predictions (e.g., Staub & Clifton, 2006; Yoshida, Dickey & Sturt, 2013. However, less is known about structural prediction in aphasia. There is evidence that lexical prediction may be spared in aphasia (Dickey et al., 2014; Love & Webb, 1977; cf. Mack et al, 2013. However, predictive mechanisms supporting facilitated lexical access may not necessarily support structural facilitation. Given that many people with aphasia (PWA exhibit syntactic deficits (e.g. Goodglass, 1993, PWA with such impairments may not engage in structural prediction. However, recent evidence suggests that some PWA may indeed predict upcoming structure (Hanne, Burchert, De Bleser, & Vashishth, 2015. Hanne et al. tracked the eyes of PWA (n=8 with sentence-comprehension deficits while they listened to reversible subject-verb-object (SVO and object-verb-subject (OVS sentences in German, in a sentence-picture matching task. Hanne et al. manipulated case and number marking to disambiguate the sentences’ structure. Gazes to an OVS or SVO picture during the unfolding of a sentence were assumed to indicate prediction of the structure congruent with that picture. According to this measure, the PWA’s structural prediction was impaired compared to controls, but they did successfully predict upcoming structure when morphosyntactic cues were strong and unambiguous. Hanne et al.’s visual-world evidence is suggestive, but their forced-choice sentence-picture matching task places tight constraints on possible structural predictions. Clearer evidence of structural prediction would come from paradigms where the content of upcoming material is not as constrained. The current study used self-paced reading study to examine structural prediction among PWA in less constrained contexts. PWA (n=17 who

  15. Aggregate driver model to enable predictable behaviour

    Science.gov (United States)

    Chowdhury, A.; Chakravarty, T.; Banerjee, T.; Balamuralidhar, P.

    2015-09-01

    The categorization of driving styles, particularly in terms of aggressiveness and skill is an emerging area of interest under the broader theme of intelligent transportation. There are two possible discriminatory techniques that can be applied for such categorization; a microscale (event based) model and a macro-scale (aggregate) model. It is believed that an aggregate model will reveal many interesting aspects of human-machine interaction; for example, we may be able to understand the propensities of individuals to carry out a given task over longer periods of time. A useful driver model may include the adaptive capability of the human driver, aggregated as the individual propensity to control speed/acceleration. Towards that objective, we carried out experiments by deploying smartphone based application to be used for data collection by a group of drivers. Data is primarily being collected from GPS measurements including position & speed on a second-by-second basis, for a number of trips over a two months period. Analysing the data set, aggregate models for individual drivers were created and their natural aggressiveness were deduced. In this paper, we present the initial results for 12 drivers. It is shown that the higher order moments of the acceleration profile is an important parameter and identifier of journey quality. It is also observed that the Kurtosis of the acceleration profiles stores major information about the driving styles. Such an observation leads to two different ranking systems based on acceleration data. Such driving behaviour models can be integrated with vehicle and road model and used to generate behavioural model for real traffic scenario.

  16. Prediction of alumina penetration

    Energy Technology Data Exchange (ETDEWEB)

    Mandell, D A

    1993-02-01

    The MESA hydrocode was used to predict two-dimensional tests of L/D 10 and L/D 15 tungsten rods impacting AD 90 alumina with a steel backing. The residual penetration into the steel is the measured quantity in these experiments conducted at the Southwest Research Institute (SWR). The interface velocity as a function of time between an alumina target and a lithium fluoride window, impacted by an alumina disk at velocities between 544 m/s and 2329 m/s, was also predicted. These one-dimensional flyer plate experiments were conducted at Sandia National Laboratories using Coors AD 995 alumina. The material strength and fracture models are important in the prediction of ceramic experiments. The models used in these predictions are discussed. The penetrations in the two-dimensional tests were predicted to 11.4 percent or better. In five of the six experiments, the predicted penetration depth was deeper than the measured value. This trend is expected since the calculation is based on ideal conditions. The results show that good agreement between the 1-D flyer plate data and the MESA predictions exists at the lower impact velocities, but the maximum velocity is overpredicted as the flyer plate velocity increases. At a flyer plate velocity of 2329 m/s the code overpredicted the data by 12.3 percent.

  17. Evolution prediction from tomography

    Science.gov (United States)

    Dominy, Jason M.; Venuti, Lorenzo Campos; Shabani, Alireza; Lidar, Daniel A.

    2017-03-01

    Quantum process tomography provides a means of measuring the evolution operator for a system at a fixed measurement time t. The problem of using that tomographic snapshot to predict the evolution operator at other times is generally ill-posed since there are, in general, infinitely many distinct and compatible solutions. We describe the prediction, in some "maximal ignorance" sense, of the evolution of a quantum system based on knowledge only of the evolution operator for finitely many times 0evolution at times away from the measurement times. Even if the original evolution is unitary, the predicted evolution is described by a non-unitary, completely positive map.

  18. Wind power prediction models

    Science.gov (United States)

    Levy, R.; Mcginness, H.

    1976-01-01

    Investigations were performed to predict the power available from the wind at the Goldstone, California, antenna site complex. The background for power prediction was derived from a statistical evaluation of available wind speed data records at this location and at nearby locations similarly situated within the Mojave desert. In addition to a model for power prediction over relatively long periods of time, an interim simulation model that produces sample wind speeds is described. The interim model furnishes uncorrelated sample speeds at hourly intervals that reproduce the statistical wind distribution at Goldstone. A stochastic simulation model to provide speed samples representative of both the statistical speed distributions and correlations is also discussed.

  19. Wind Power Prediction Investigation

    Directory of Open Access Journals (Sweden)

    Yuanlong Liu

    2013-02-01

    Full Text Available Daily and real-time forecast data of wind power is predicted in this study using three methods, which are Kalman filter model, GARCH model and time-series-based BP neural network model. Then, owing to evaluation to the calculation of accuracy and qualification rate, the best method, the time-series-based BP neural network model, was selected for its highest accuracy. Moreover, the prediction error influence due to convergence of wind turbine is on consideration according to the evaluation. Finally, suggestions of improving the prediction accuracy were put forward based on the discussion of accuracy-obstacle factors.

  20. Methane prediction in collieries

    CSIR Research Space (South Africa)

    Creedy, DP

    1999-06-01

    Full Text Available The primary aim of the project was to assess the current status of research on methane emission prediction for collieries in South Africa in comparison with methods used and advances achieved elsewhere in the world....

  1. Predicted value of $0 \\, \

    CERN Document Server

    Maedan, Shinji

    2016-01-01

    Assuming that the lightest neutrino mass $ m_0 $ is measured, we study the influence of error of the measured $ m_0 $ on the uncertainty of the predicted value of the neutrinoless double beta decay ($0 \\, \

  2. CMAQ predicted concentration files

    Data.gov (United States)

    U.S. Environmental Protection Agency — CMAQ predicted ozone. This dataset is associated with the following publication: Gantt, B., G. Sarwar, J. Xing, H. Simon, D. Schwede, B. Hutzell, R. Mathur, and A....

  3. Predictable grammatical constructions

    DEFF Research Database (Denmark)

    Lucas, Sandra

    2015-01-01

    My aim in this paper is to provide evidence from diachronic linguistics for the view that some predictable units are entrenched in grammar and consequently in human cognition, in a way that makes them functionally and structurally equal to nonpredictable grammatical units, suggesting...... that these predictable units should be considered grammatical constructions on a par with the nonpredictable constructions. Frequency has usually been seen as the only possible argument speaking in favor of viewing some formally and semantically fully predictable units as grammatical constructions. However, this paper...... semantically and formally predictable. Despite this difference, [méllo INF], like the other future periphrases, seems to be highly entrenched in the cognition (and grammar) of Early Medieval Greek language users, and consequently a grammatical construction. The syntactic evidence speaking in favor of [méllo...

  4. Highlights, predictions, and changes.

    Science.gov (United States)

    Jeang, Kuan-Teh

    2012-11-15

    Recent literature highlights at Retrovirology are described. Predictions are made regarding "hot" retrovirology research trends for the coming year based on recent journal access statistics. Changes in Retrovirology editor and the frequency of the Retrovirology Prize are announced.

  5. Predicting toxicity of nanoparticles

    OpenAIRE

    BURELLO ENRICO; Worth, Andrew

    2011-01-01

    A statistical model based on a quantitative structure–activity relationship accurately predicts the cytotoxicity of various metal oxide nanoparticles, thus offering a way to rapidly screen nanomaterials and prioritize testing.

  6. Outcome predictability biases learning.

    Science.gov (United States)

    Griffiths, Oren; Mitchell, Chris J; Bethmont, Anna; Lovibond, Peter F

    2015-01-01

    Much of contemporary associative learning research is focused on understanding how and when the associative history of cues affects later learning about those cues. Very little work has investigated the effects of the associative history of outcomes on human learning. Three experiments extended the "learned irrelevance" paradigm from the animal conditioning literature to examine the influence of an outcome's prior predictability on subsequent learning of relationships between cues and that outcome. All 3 experiments found evidence for the idea that learning is biased by the prior predictability of the outcome. Previously predictable outcomes were readily associated with novel predictive cues, whereas previously unpredictable outcomes were more readily associated with novel nonpredictive cues. This finding highlights the importance of considering the associative history of outcomes, as well as cues, when interpreting multistage designs. Associative and cognitive explanations of this certainty matching effect are discussed.

  7. Chapter VII. Predicting Fertility

    Science.gov (United States)

    Section 2. Visual and Microscopic Approaches for Differentiating Unfertilized Germinal Discs and Early dead Embryos from Pre-Incubated Blastoderms Section 3. Predicting the Duration of fertility by Counting Sperm in the Outer Perivitelline Layer of Laid Eggs...

  8. Predictable return distributions

    DEFF Research Database (Denmark)

    Pedersen, Thomas Quistgaard

    This paper provides detailed insights into predictability of the entire stock and bond return distribution through the use of quantile regression. This allows us to examine speci…c parts of the return distribution such as the tails or the center, and for a suf…ciently …ne grid of quantiles we can...... are predictable as a function of economic state variables. The results are, however, very different for stocks and bonds. The state variables primarily predict only location shifts in the stock return distribution, while they also predict changes in higher-order moments in the bond return distribution. Out...... trace out the entire distribution. A univariate quantile regression model is used to examine stock and bond return distributions individually, while a multivariate model is used to capture their joint distribution. An empirical analysis on US data shows that certain parts of the return distributions...

  9. Predicting Online Purchasing Behavior

    OpenAIRE

    W.R BUCKINX; D. VAN DEN POEL

    2003-01-01

    This empirical study investigates the contribution of different types of predictors to the purchasing behaviour at an online store. We use logit modelling to predict whether or not a purchase is made during the next visit to the website using both forward and backward variable-selection techniques, as well as Furnival and Wilson’s global score search algorithm to find the best subset of predictors. We contribute to the literature by using variables from four different categories in predicting...

  10. Stuck pipe prediction

    KAUST Repository

    Alzahrani, Majed

    2016-03-10

    Disclosed are various embodiments for a prediction application to predict a stuck pipe. A linear regression model is generated from hook load readings at corresponding bit depths. A current hook load reading at a current bit depth is compared with a normal hook load reading from the linear regression model. A current hook load greater than a normal hook load for a given bit depth indicates the likelihood of a stuck pipe.

  11. Nonparametric Predictive Regression

    OpenAIRE

    Ioannis Kasparis; Elena Andreou; Phillips, Peter C.B.

    2012-01-01

    A unifying framework for inference is developed in predictive regressions where the predictor has unknown integration properties and may be stationary or nonstationary. Two easily implemented nonparametric F-tests are proposed. The test statistics are related to those of Kasparis and Phillips (2012) and are obtained by kernel regression. The limit distribution of these predictive tests holds for a wide range of predictors including stationary as well as non-stationary fractional and near unit...

  12. Aircraft Noise Prediction

    OpenAIRE

    2014-01-01

    This contribution addresses the state-of-the-art in the field of aircraft noise prediction, simulation and minimisation. The point of view taken in this context is that of comprehensive models that couple the various aircraft systems with the acoustic sources, the propagation and the flight trajectories. After an exhaustive review of the present predictive technologies in the relevant fields (airframe, propulsion, propagation, aircraft operations, trajectory optimisation), the paper add...

  13. Uncertainty quantified trait predictions

    Science.gov (United States)

    Fazayeli, Farideh; Kattge, Jens; Banerjee, Arindam; Schrodt, Franziska; Reich, Peter

    2015-04-01

    Functional traits of organisms are key to understanding and predicting biodiversity and ecological change, which motivates continuous collection of traits and their integration into global databases. Such composite trait matrices are inherently sparse, severely limiting their usefulness for further analyses. On the other hand, traits are characterized by the phylogenetic trait signal, trait-trait correlations and environmental constraints, all of which provide information that could be used to statistically fill gaps. We propose the application of probabilistic models which, for the first time, utilize all three characteristics to fill gaps in trait databases and predict trait values at larger spatial scales. For this purpose we introduce BHPMF, a hierarchical Bayesian extension of Probabilistic Matrix Factorization (PMF). PMF is a machine learning technique which exploits the correlation structure of sparse matrices to impute missing entries. BHPMF additionally utilizes the taxonomic hierarchy for trait prediction. Implemented in the context of a Gibbs Sampler MCMC approach BHPMF provides uncertainty estimates for each trait prediction. We present comprehensive experimental results on the problem of plant trait prediction using the largest database of plant traits, where BHPMF shows strong empirical performance in uncertainty quantified trait prediction, outperforming the state-of-the-art based on point estimates. Further, we show that BHPMF is more accurate when it is confident, whereas the error is high when the uncertainty is high.

  14. Predicting affective choice.

    Science.gov (United States)

    Suri, Gaurav; Sheppes, Gal; Gross, James J

    2013-08-01

    Affect is increasingly recognized as central to decision making. However, it is not clear whether affect can be used to predict choice. To address this issue, we conducted 4 studies designed to create and test a model that could predict choice from affect. In Study 1, we used an image rating task to develop a model that predicted approach-avoidance motivations. This model quantified the role of two basic dimensions of affect--valence and arousal--in determining choice. We then tested the predictive power of this model for two types of decisions involving images: preference based selections (Study 2) and risk-reward trade-offs (Study 3). In both cases, the model derived in Study 1 predicted choice and outperformed competing models drawn from well-established theoretical views. Finally, we showed that this model has ecological validity: It predicted choices between news articles on the basis of headlines (Study 4). These findings have implications for diverse fields, including neuroeconomics and judgment and decision making. PsycINFO Database Record (c) 2013 APA, all rights reserved.

  15. Operational Dust Prediction

    Science.gov (United States)

    Benedetti, Angela; Baldasano, Jose M.; Basart, Sara; Benincasa, Francesco; Boucher, Olivier; Brooks, Malcolm E.; Chen, Jen-Ping; Colarco, Peter R.; Gong, Sunlin; Huneeus, Nicolas; Jones, Luke; Lu, Sarah; Menut, Laurent; Morcrette, Jean-Jacques; Mulcahy, Jane; Nickovic, Slobodan; Garcia-Pando, Carlos P.; Reid, Jeffrey S.; Sekiyama, Thomas T.; Tanaka, Taichu Y.; Terradellas, Enric; Westphal, Douglas L.; Zhang, Xiao-Ye; Zhou, Chun-Hong

    2014-01-01

    Over the last few years, numerical prediction of dust aerosol concentration has become prominent at several research and operational weather centres due to growing interest from diverse stakeholders, such as solar energy plant managers, health professionals, aviation and military authorities and policymakers. Dust prediction in numerical weather prediction-type models faces a number of challenges owing to the complexity of the system. At the centre of the problem is the vast range of scales required to fully account for all of the physical processes related to dust. Another limiting factor is the paucity of suitable dust observations available for model, evaluation and assimilation. This chapter discusses in detail numerical prediction of dust with examples from systems that are currently providing dust forecasts in near real-time or are part of international efforts to establish daily provision of dust forecasts based on multi-model ensembles. The various models are introduced and described along with an overview on the importance of dust prediction activities and a historical perspective. Assimilation and evaluation aspects in dust prediction are also discussed.

  16. Dynamics and predictability of a low-order wind-driven ocean-atmosphere coupled model

    Science.gov (United States)

    Vannitsem, Stéphane

    2014-04-01

    The dynamics of a low-order coupled wind-driven ocean-atmosphere system is investigated with emphasis on its predictability properties. The low-order coupled deterministic system is composed of a baroclinic atmosphere for which 12 dominant dynamical modes are only retained (Charney and Straus in J Atmos Sci 37:1157-1176, 1980) and a wind-driven, quasi-geostrophic and reduced-gravity shallow ocean whose field is truncated to four dominant modes able to reproduce the large scale oceanic gyres (Pierini in J Phys Oceanogr 41:1585-1604, 2011). The two models are coupled through mechanical forcings only. The analysis of its dynamics reveals first that under aperiodic atmospheric forcings only dominant single gyres (clockwise or counterclockwise) appear, while for periodic atmospheric solutions the double gyres emerge. In the present model domain setting context, this feature is related to the level of truncation of the atmospheric fields, as indicated by a preliminary analysis of the impact of higher wavenumber ("synoptic" scale) modes on the development of oceanic gyres. In the latter case, double gyres appear in the presence of a chaotic atmosphere. Second the dynamical quantities characterizing the short-term predictability (Lyapunov exponents, Lyapunov dimension, Kolmogorov-Sinaï (KS) entropy) displays a complex dependence as a function of the key parameters of the system, namely the coupling strength and the external thermal forcing. In particular, the KS-entropy is increasing as a function of the coupling in most of the experiments, implying an increase of the rate of loss of information about the localization of the system on its attractor. Finally the dynamics of the error is explored and indicates, in particular, a rich variety of short term behaviors of the error in the atmosphere depending on the (relative) amplitude of the initial error affecting the ocean, from polynomial ( at 2 + bt 3 + ct 4) up to exponential-like evolutions. These features are explained

  17. Location predicting methods for UAVs

    Science.gov (United States)

    Peng, Xiaodong; Zhang, Yu

    2017-08-01

    Location prediction of unmanned aerial vehicle (UAV) is important for fighting with its enemy and ensuring its normal operation. This paper presents the motion model of UAVs and reduces the state space into 7 dimensions. The Bayesian Network, Markov Chain, Curve Fitting and Neural Network are introduced for designing predicting methods. Then Curve Fitting Predicting method, Markov Chain Predicting method, Bayesian Network Predicting method and Neural Network Predicting method are designed for UAVs. The simulation result shows that 1) Neural Network Predicting method has highest predicting accuracy; 2) Markov Chain Predicting method and Bayesian Network Predicting method methods have similar performance and both are better than Bayesian Network Predicting method methods; 3) Neural Network Predicting method is the first choice when predicting the locations of UAVs.

  18. Cytomics in predictive medicine

    Science.gov (United States)

    Tarnok, Attila; Valet, Guenther K.

    2004-07-01

    Predictive Medicine aims at the detection of changes in patient's disease state prior to the manifestation of deterioration or improvement of the current status. Patient-specific, disease-course predictions with >95% or >99% accuracy during therapy would be highly valuable for everyday medicine. If these predictors were available, disease aggravation or progression, frequently accompanied by irreversible tissue damage or therapeutic side effects, could then potentially be avoided by early preventive therapy. The molecular analysis of heterogeneous cellular systems (Cytomics) by cytometry in conjunction with pattern-oriented bioinformatic analysis of the multiparametric cytometric and other data provides a promising approach to individualized or personalized medical treatment or disease management. Predictive medicine is best implemented by cell oriented measurements e.g. by flow or image cytometry. Cell oriented gene or protein arrays as well as bead arrays for the capture of solute molecules form serum, plasma, urine or liquor are equally of high value. Clinical applications of predictive medicine by Cytomics will include multi organ failure in sepsis or non infectious posttraumatic shock in intensive care, or the pretherapeutic identification of high risk patients in cancer cytostatic. Early individualized therapy may provide better survival chances for individual patient at concomitant cost containment. Predictive medicine guided early reduction or stop of therapy may lower or abrogate potential therapeutic side effects. Further important aspects of predictive medicine concern the preoperative identification of patients with a tendency for postoperative complications or coronary artery disease patients with an increased tendency for restenosis. As a consequence, better patient care and new forms of inductive scientific hypothesis development based on the interpretation of predictive data patterns are at reach.

  19. Candidate Prediction Models and Methods

    DEFF Research Database (Denmark)

    Nielsen, Henrik Aalborg; Nielsen, Torben Skov; Madsen, Henrik

    2005-01-01

    This document lists candidate prediction models for Work Package 3 (WP3) of the PSO-project called ``Intelligent wind power prediction systems'' (FU4101). The main focus is on the models transforming numerical weather predictions into predictions of power production. The document also outlines...... the possibilities w.r.t. different numerical weather predictions actually available to the project....

  20. Aircraft noise prediction

    Science.gov (United States)

    Filippone, Antonio

    2014-07-01

    This contribution addresses the state-of-the-art in the field of aircraft noise prediction, simulation and minimisation. The point of view taken in this context is that of comprehensive models that couple the various aircraft systems with the acoustic sources, the propagation and the flight trajectories. After an exhaustive review of the present predictive technologies in the relevant fields (airframe, propulsion, propagation, aircraft operations, trajectory optimisation), the paper addresses items for further research and development. Examples are shown for several airplanes, including the Airbus A319-100 (CFM engines), the Bombardier Dash8-Q400 (PW150 engines, Dowty R408 propellers) and the Boeing B737-800 (CFM engines). Predictions are done with the flight mechanics code FLIGHT. The transfer function between flight mechanics and the noise prediction is discussed in some details, along with the numerical procedures for validation and verification. Some code-to-code comparisons are shown. It is contended that the field of aircraft noise prediction has not yet reached a sufficient level of maturity. In particular, some parametric effects cannot be investigated, issues of accuracy are not currently addressed, and validation standards are still lacking.

  1. Predicting tile drainage discharge

    DEFF Research Database (Denmark)

    Iversen, Bo Vangsø; Kjærgaard, Charlotte; Petersen, Rasmus Jes;

    of the water load coming from the tile drainage system is therefore essential. This work aims at predicting tile drainage discharge using dynamic as well as a statistical predictive models. A large dataset of historical tile drain discharge data, daily discharge values as well as yearly average values were......More than 50 % of Danish agricultural areas are expected to be artificial tile drained. Transport of water and nutrients through the tile drain system to the aquatic environment is expected to be significant. For different mitigation strategies such as constructed wetlands an exact knowledge...... used in the analysis. For the dynamic modelling, a simple linear reservoir model was used where different outlets in the model represented tile drain as well as groundwater discharge outputs. This modelling was based on daily measured tile drain discharge values. The statistical predictive model...

  2. Predicting Ideological Prejudice

    Science.gov (United States)

    Brandt, Mark J.

    2017-01-01

    A major shortcoming of current models of ideological prejudice is that although they can anticipate the direction of the association between participants’ ideology and their prejudice against a range of target groups, they cannot predict the size of this association. I developed and tested models that can make specific size predictions for this association. A quantitative model that used the perceived ideology of the target group as the primary predictor of the ideology-prejudice relationship was developed with a representative sample of Americans (N = 4,940) and tested against models using the perceived status of and choice to belong to the target group as predictors. In four studies (total N = 2,093), ideology-prejudice associations were estimated, and these observed estimates were compared with the models’ predictions. The model that was based only on perceived ideology was the most parsimonious with the smallest errors. PMID:28394693

  3. Partially predictable chaos

    CERN Document Server

    Wernecke, Hendrik; Gros, Claudius

    2016-01-01

    For a chaotic system pairs of initially close-by trajectories become eventually fully uncorrelated on the attracting set. This process of decorrelation is split into an initial decrease characterized by the maximal Lyapunov exponent and a subsequent diffusive process on the chaotic attractor causing the final loss of predictability. The time scales of both processes can be either of the same or of very different orders of magnitude. In the latter case the two trajectories linger within a finite but small distance (with respect to the overall size of the attractor) for exceedingly long times and therefore remain partially predictable. We introduce a 0-1 indicator for chaos capable of describing this scenario, arguing, in addition, that the chaotic closed braids found close to a period-doubling transition are generically partially predictable.

  4. Predicting Anthracycline Benefit

    DEFF Research Database (Denmark)

    Bartlett, John M S; McConkey, Christopher C; Munro, Alison F

    2015-01-01

    PURPOSE: Evidence supporting the clinical utility of predictive biomarkers of anthracycline activity is weak, with a recent meta-analysis failing to provide strong evidence for either HER2 or TOP2A. Having previously shown that duplication of chromosome 17 pericentromeric alpha satellite as measu......PURPOSE: Evidence supporting the clinical utility of predictive biomarkers of anthracycline activity is weak, with a recent meta-analysis failing to provide strong evidence for either HER2 or TOP2A. Having previously shown that duplication of chromosome 17 pericentromeric alpha satellite...

  5. Prediction of Antibody Epitopes

    DEFF Research Database (Denmark)

    Nielsen, Morten; Marcatili, Paolo

    2015-01-01

    Antibodies recognize their cognate antigens in a precise and effective way. In order to do so, they target regions of the antigenic molecules that have specific features such as large exposed areas, presence of charged or polar atoms, specific secondary structure elements, and lack of similarity...... to self-proteins. Given the sequence or the structure of a protein of interest, several methods exploit such features to predict the residues that are more likely to be recognized by an immunoglobulin.Here, we present two methods (BepiPred and DiscoTope) to predict linear and discontinuous antibody...

  6. Linguistic Structure Prediction

    CERN Document Server

    Smith, Noah A

    2011-01-01

    A major part of natural language processing now depends on the use of text data to build linguistic analyzers. We consider statistical, computational approaches to modeling linguistic structure. We seek to unify across many approaches and many kinds of linguistic structures. Assuming a basic understanding of natural language processing and/or machine learning, we seek to bridge the gap between the two fields. Approaches to decoding (i.e., carrying out linguistic structure prediction) and supervised and unsupervised learning of models that predict discrete structures as outputs are the focus. W

  7. Nuclear level density predictions

    Directory of Open Access Journals (Sweden)

    Bucurescu Dorel

    2015-01-01

    Full Text Available Simple formulas depending only on nuclear masses were previously proposed for the parameters of the Back-Shifted Fermi Gas (BSFG model and of the Constant Temperature (CT model of the nuclear level density, respectively. They are now applied for the prediction of the level density parameters of all nuclei with available masses. Both masses from the new 2012 mass table and from different models are considered and the predictions are discussed in connection with nuclear regions most affected by shell corrections and nuclear structure effects and relevant for the nucleosynthesis.

  8. Basis of predictive mycology.

    Science.gov (United States)

    Dantigny, Philippe; Guilmart, Audrey; Bensoussan, Maurice

    2005-04-15

    For over 20 years, predictive microbiology focused on food-pathogenic bacteria. Few studies concerned modelling fungal development. On one hand, most of food mycologists are not familiar with modelling techniques; on the other hand, people involved in modelling are developing tools dedicated to bacteria. Therefore, there is a tendency to extend the use of models that were developed for bacteria to moulds. However, some mould specificities should be taken into account. The use of specific models for predicting germination and growth of fungi was advocated previously []. This paper provides a short review of fungal modelling studies.

  9. A Characterization of Prediction Errors

    OpenAIRE

    Meek, Christopher

    2016-01-01

    Understanding prediction errors and determining how to fix them is critical to building effective predictive systems. In this paper, we delineate four types of prediction errors and demonstrate that these four types characterize all prediction errors. In addition, we describe potential remedies and tools that can be used to reduce the uncertainty when trying to determine the source of a prediction error and when trying to take action to remove a prediction errors.

  10. Predicting Classroom Success.

    Science.gov (United States)

    Kessler, Ronald P.

    A study was conducted at Rancho Santiago College (RSC) to identify personal and academic factors that are predictive of students' success in their courses. The study examined the following possible predictors of success: language and math test scores; background characteristics; length of time out of high school; high school background; college…

  11. Genetically optimizing weather predictions

    Science.gov (United States)

    Potter, S. B.; Staats, Kai; Romero-Colmenero, Encarni

    2016-07-01

    humidity, air pressure, wind speed and wind direction) into a database. Built upon this database, we have developed a remarkably simple approach to derive a functional weather predictor. The aim is provide up to the minute local weather predictions in order to e.g. prepare dome environment conditions ready for night time operations or plan, prioritize and update weather dependent observing queues. In order to predict the weather for the next 24 hours, we take the current live weather readings and search the entire archive for similar conditions. Predictions are made against an averaged, subsequent 24 hours of the closest matches for the current readings. We use an Evolutionary Algorithm to optimize our formula through weighted parameters. The accuracy of the predictor is routinely tested and tuned against the full, updated archive to account for seasonal trends and total, climate shifts. The live (updated every 5 minutes) SALT weather predictor can be viewed here: http://www.saao.ac.za/ sbp/suthweather_predict.html

  12. PREDICTION OF OVULATION

    Institute of Scientific and Technical Information of China (English)

    LIUYong; CHENSu-Ru; ZHOUJin-Ting; LIUJi-Ying

    1989-01-01

    The purpose or this research is: I) to observe the secretory pattern of five reproductive hormones in Chinese women with normal menstrual cyclcs, especially at the prc-ovulatory peroid; 2) to study whether urinary LH measurement could be used instead of serum LH measurement; 3) to evaluate the significance of LH-EIA kit (Right-Day) for ovulation prediction.

  13. Prediction method abstracts

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-12-31

    This conference was held December 4--8, 1994 in Asilomar, California. The purpose of this meeting was to provide a forum for exchange of state-of-the-art information concerning the prediction of protein structure. Attention if focused on the following: comparative modeling; sequence to fold assignment; and ab initio folding.

  14. Predictive models in urology.

    Science.gov (United States)

    Cestari, Andrea

    2013-01-01

    Predictive modeling is emerging as an important knowledge-based technology in healthcare. The interest in the use of predictive modeling reflects advances on different fronts such as the availability of health information from increasingly complex databases and electronic health records, a better understanding of causal or statistical predictors of health, disease processes and multifactorial models of ill-health and developments in nonlinear computer models using artificial intelligence or neural networks. These new computer-based forms of modeling are increasingly able to establish technical credibility in clinical contexts. The current state of knowledge is still quite young in understanding the likely future direction of how this so-called 'machine intelligence' will evolve and therefore how current relatively sophisticated predictive models will evolve in response to improvements in technology, which is advancing along a wide front. Predictive models in urology are gaining progressive popularity not only for academic and scientific purposes but also into the clinical practice with the introduction of several nomograms dealing with the main fields of onco-urology.

  15. Predicting Visibility of Aircraft

    Science.gov (United States)

    Watson, Andrew; Ramirez, Cesar V.; Salud, Ellen

    2009-01-01

    Visual detection of aircraft by human observers is an important element of aviation safety. To assess and ensure safety, it would be useful to be able to be able to predict the visibility, to a human observer, of an aircraft of specified size, shape, distance, and coloration. Examples include assuring safe separation among aircraft and between aircraft and unmanned vehicles, design of airport control towers, and efforts to enhance or suppress the visibility of military and rescue vehicles. We have recently developed a simple metric of pattern visibility, the Spatial Standard Observer (SSO). In this report we examine whether the SSO can predict visibility of simulated aircraft images. We constructed a set of aircraft images from three-dimensional computer graphic models, and measured the luminance contrast threshold for each image from three human observers. The data were well predicted by the SSO. Finally, we show how to use the SSO to predict visibility range for aircraft of arbitrary size, shape, distance, and coloration. PMID:19462007

  16. 'Red Flag' Predictions

    DEFF Research Database (Denmark)

    Hallin, Carina Antonia; Andersen, Torben Juul; Tveterås, Sigbjørn

    This conceptual article introduces a new way to predict firm performance based on aggregation of sensing among frontline employees about changes in operational capabilities to update strategic action plans and generate innovations. We frame the approach in the context of first- and second-generat...

  17. Hypotheses and Inductive Predictions

    NARCIS (Netherlands)

    ROMEYN, J.-W.

    2008-01-01

    ABSTRACT. This paper studies the use of hypotheses schemes in generating inductive predictions. After discussing Carnap–Hintikka inductive logic, hypotheses schemes are defined and illustrated with two partitions. One partition results in the Carnapian continuum of inductive methods, the other resul

  18. Vertebral Fracture Prediction

    DEFF Research Database (Denmark)

    2008-01-01

    Vertebral Fracture Prediction A method of processing data derived from an image of at least part of a spine is provided for estimating the risk of a future fracture in vertebraeof the spine. Position data relating to at least four neighbouring vertebrae of the spine is processed. The curvature...

  19. Predicting rainfall beyond tomorrow

    Science.gov (United States)

    NOAA’s Climate Prediction Center issues climate precipitation forecasts that offer potential support for water resource managers and farmers and ranchers in New Mexico, but the forecasts are frequently misunderstood and not widely used in practical decision making. The objectives of this newsletter ...

  20. Neurological abnormalities predict disability

    DEFF Research Database (Denmark)

    Poggesi, Anna; Gouw, Alida; van der Flier, Wiesje

    2014-01-01

    To investigate the role of neurological abnormalities and magnetic resonance imaging (MRI) lesions in predicting global functional decline in a cohort of initially independent-living elderly subjects. The Leukoaraiosis And DISability (LADIS) Study, involving 11 European centres, was primarily aimed...

  1. Predicting coronary heart disease

    DEFF Research Database (Denmark)

    Sillesen, Henrik; Fuster, Valentin

    2012-01-01

    Atherosclerosis is the leading cause of death and disabling disease. Whereas risk factors are well known and constitute therapeutic targets, they are not useful for prediction of risk of future myocardial infarction, stroke, or death. Therefore, methods to identify atherosclerosis itself have been...

  2. Hypotheses and Inductive Predictions

    NARCIS (Netherlands)

    ROMEYN, J.-W.

    2008-01-01

    ABSTRACT. This paper studies the use of hypotheses schemes in generating inductive predictions. After discussing Carnap–Hintikka inductive logic, hypotheses schemes are defined and illustrated with two partitions. One partition results in the Carnapian continuum of inductive methods, the other resul

  3. Predicting Intrinsic Motivation

    Science.gov (United States)

    Martens, Rob; Kirschner, Paul A.

    2004-01-01

    Intrinsic motivation can be predicted from participants' perceptions of the social environment and the task environment (Ryan & Deci, 2000)in terms of control, relatedness and competence. To determine the degree of independence of these factors 251 students in higher vocational education (physiotherapy and hotel management) indicated the extent to…

  4. Highlights, predictions, and changes

    Directory of Open Access Journals (Sweden)

    Jeang Kuan-Teh

    2012-11-01

    Full Text Available Abstract Recent literature highlights at Retrovirology are described. Predictions are made regarding “hot” retrovirology research trends for the coming year based on recent journal access statistics. Changes in Retrovirology editor and the frequency of the Retrovirology Prize are announced.

  5. Highlights, predictions, and changes

    OpenAIRE

    Jeang Kuan-Teh

    2012-01-01

    Abstract Recent literature highlights at Retrovirology are described. Predictions are made regarding “hot” retrovirology research trends for the coming year based on recent journal access statistics. Changes in Retrovirology editor and the frequency of the Retrovirology Prize are announced.

  6. Predicting Reasoning from Memory

    Science.gov (United States)

    Heit, Evan; Hayes, Brett K.

    2011-01-01

    In an effort to assess the relations between reasoning and memory, in 8 experiments, the authors examined how well responses on an inductive reasoning task are predicted from responses on a recognition memory task for the same picture stimuli. Across several experimental manipulations, such as varying study time, presentation frequency, and the…

  7. MODEL PREDICTIVE CONTROL FUNDAMENTALS

    African Journals Online (AJOL)

    2012-07-02

    Jul 2, 2012 ... paper, we will present an introduction to the theory and application of MPC with Matlab codes written to ... model predictive control, linear systems, discrete-time systems, ... and then compute very rapidly for this open-loop con-.

  8. THE PREDICTION OF OVULATION

    Institute of Scientific and Technical Information of China (English)

    WANGXin-Xing; ZHAShu-Wei; WUZhou-Ya

    1989-01-01

    The authors present their work on the prediction of ovulation in forty-five women with normal menstrual cycles for a total of 72 cycles by several indices, including ultrasonography, BBT graph, cervical mucus and mittelschmerz, LH peak values were also determined for reference in 20 cases ( 20 cycles ), Results are as follows:

  9. Predicting Lotto Numbers

    NARCIS (Netherlands)

    Jorgensen, C.B.; Suetens, S.; Tyran, J.R.

    2011-01-01

    We investigate the "law of small numbers" using a unique panel data set on lotto gambling. Because we can track individual players over time, we can measure how they react to outcomes of recent lotto drawings. We can therefore test whether they behave as if they believe they can predict lotto

  10. Candidate Prediction Models and Methods

    DEFF Research Database (Denmark)

    Nielsen, Henrik Aalborg; Nielsen, Torben Skov; Madsen, Henrik

    2005-01-01

    This document lists candidate prediction models for Work Package 3 (WP3) of the PSO-project called ``Intelligent wind power prediction systems'' (FU4101). The main focus is on the models transforming numerical weather predictions into predictions of power production. The document also outlines...

  11. Predictability of Solar Flares

    Science.gov (United States)

    Mares, Peter; Balasubramaniam, K. S.

    2009-05-01

    Solar flares are significant drivers of space weather. With the availability of high cadence solar chromospheric and photospheric data from the USAF's Optical Solar PAtrol Network (OSPAN; photosphere and chromosphere imaging) Telescope and the Global Oscillations Network Group (GONG; photosphere magnetic imaging), at the National Solar Observatory, we have gained insights into potential uses of the data for solar flare prediction. We apply the Principal Component Analysis (PCA) to parameterize the flaring system and extract consistent observables at solar chromospheric and photospheric layers that indicate a viable recognition of flaring activity. Rather than limiting ourselves to a few known indicators of solar activity, PCA helps us to characterize the entire system using several tens of variables for each observed layer. The components of the Eigen vectors derived from PCA help us recognize and quantify innate characteristics of solar flares and compare them. We will present an analysis of these results to explore the viability of PCA to assist in predicting solar flares.

  12. Crystal structure and prediction.

    Science.gov (United States)

    Thakur, Tejender S; Dubey, Ritesh; Desiraju, Gautam R

    2015-04-01

    The notion of structure is central to the subject of chemistry. This review traces the development of the idea of crystal structure since the time when a crystal structure could be determined from a three-dimensional diffraction pattern and assesses the feasibility of computationally predicting an unknown crystal structure of a given molecule. Crystal structure prediction is of considerable fundamental and applied importance, and its successful execution is by no means a solved problem. The ease of crystal structure determination today has resulted in the availability of large numbers of crystal structures of higher-energy polymorphs and pseudopolymorphs. These structural libraries lead to the concept of a crystal structure landscape. A crystal structure of a compound may accordingly be taken as a data point in such a landscape.

  13. Chaos detection and predictability

    CERN Document Server

    Gottwald, Georg; Laskar, Jacques

    2016-01-01

    Distinguishing chaoticity from regularity in deterministic dynamical systems and specifying the subspace of the phase space in which instabilities are expected to occur is of utmost importance in as disparate areas as astronomy, particle physics and climate dynamics.   To address these issues there exists a plethora of methods for chaos detection and predictability. The most commonly employed technique for investigating chaotic dynamics, i.e. the computation of Lyapunov exponents, however, may suffer a number of problems and drawbacks, for example when applied to noisy experimental data.   In the last two decades, several novel methods have been developed for the fast and reliable determination of the regular or chaotic nature of orbits, aimed at overcoming the shortcomings of more traditional techniques. This set of lecture notes and tutorial reviews serves as an introduction to and overview of modern chaos detection and predictability techniques for graduate students and non-specialists.   The book cover...

  14. Predicting Bankruptcy in Pakistan

    Directory of Open Access Journals (Sweden)

    Abdul RASHID

    2011-09-01

    Full Text Available This paper aims to identify the financial ratios that are most significant in bankruptcy prediction for the non-financial sector of Pakistan based on a sample of companies which became bankrupt over the time period 1996-2006. Twenty four financial ratios covering four important financial attributes, namely profitability, liquidity, leverage, and turnover ratios, were examined for a five-year period prior bankruptcy. The discriminant analysis produced a parsimonious model of three variables viz. sales to total assets, EBIT to current liabilities, and cash flow ratio. Our estimates provide evidence that the firms having Z-value below zero fall into the “bankrupt” whereas the firms with Z-value above zero fall into the “non-bankrupt” category. The model achieved 76.9% prediction accuracy when it is applied to forecast bankruptcies on the underlying sample.

  15. Prediction of delayed subsidence

    Science.gov (United States)

    Burns, K.

    A predictive model of delayed subsidence is discussed. A numerical implementation is tested on one of the best-described study areas, Allegheny County in Pennsylvania. In planning insurance of restitution measures, a predictive model is of value in estimating the magnitude of the problem and the size of long-term budgetary commitments. Contrary to active subsidence, which occurs concurrently with mining operations, or is completed within a few days following coal extraction, delayed subsidence may take many years to appear at the surface after coal mines are abandoned. There are two principal morphological types of delayed subsidence: troughs, which are shallow depressions, and sinks, which are steep-sided crown pits. Both types are damaging to surface structures, and a variety of methods were introduced to deal with the problem, ranging from subsidence insurance to site restitution.

  16. Predicting Lotto Numbers

    DEFF Research Database (Denmark)

    Jørgensen, Claus Bjørn; Suetens, Sigrid; Tyran, Jean-Robert

    numbers based on recent drawings. While most players pick the same set of numbers week after week without regards of numbers drawn or anything else, we find that those who do change, act on average in the way predicted by the law of small numbers as formalized in recent behavioral theory. In particular......We investigate the “law of small numbers” using a unique panel data set on lotto gambling. Because we can track individual players over time, we can measure how they react to outcomes of recent lotto drawings. We can therefore test whether they behave as if they believe they can predict lotto......, on average they move away from numbers that have recently been drawn, as suggested by the “gambler’s fallacy”, and move toward numbers that are on streak, i.e. have been drawn several weeks in a row, consistent with the “hot hand fallacy”....

  17. Essays on Earnings Predictability

    DEFF Research Database (Denmark)

    Bruun, Mark

    affect the accuracy of analysts´earnings forecasts. Finally, the objective of the dissertation is to investigate how the stock market is affected by the accuracy of corporate earnings projections. The dissertation contributes to a deeper understanding of these issues. First, it is shown how earnings...... of analysts’ earnings forecasts. Furthermore, the dissertation shows how the stock market’s reaction to the disclosure of information about corporate earnings depends on how well corporate earnings can be predicted. The dissertation indicates that the stock market’s reaction to the disclosure of earnings...... forecasts are not more accurate than the simpler forecasts based on a historical timeseries of earnings. Secondly, the dissertation shows how accounting standards affect analysts’ earnings predictions. Accounting conservatism contributes to a more volatile earnings process, which lowers the accuracy...

  18. Prediction of the

    Directory of Open Access Journals (Sweden)

    Prasenjit Dey

    2016-06-01

    Full Text Available The aerodynamic behavior of a square cylinder with rounded corner edges in steady flow regime in the range of Reynolds number (Re 5–45; is predicted by Artificial Neural Network (ANN using MATLAB. The ANN has trained by back propagation algorithm. The ANN requires input and output data to train the network, which is obtained from the commercial Computational Fluid Dynamics (CFD software FLUENT in the present study. In FLUENT, all the governing equations are discretized by the finite volume method. Results from numerical simulation and back propagation based ANN have been compared. It has been discovered that the ANN predicts the aerodynamic behavior correctly within the given range of the training data. It is additionally observed that back propagation based ANN is an effective tool to forecast the aerodynamic behavior than simulation, that has very much longer computational time.

  19. Reliability prediction techniques

    Energy Technology Data Exchange (ETDEWEB)

    Whittaker, B.; Worthington, B.; Lord, J.F.; Pinkard, D.

    1986-01-01

    The paper demonstrates the feasibility of applying reliability assessment techniques to mining equipment. A number of techniques are identified and described and examples of their use in assessing mining equipment are given. These techniques include: reliability prediction; failure analysis; design audit; maintainability; availability and the life cycle costing. Specific conclusions regarding the usefulness of each technique are outlined. The choice of techniques depends upon both the type of equipment being assessed and its stage of development, with numerical prediction best suited for electronic equipment and fault analysis and design audit suited to mechanical equipment. Reliability assessments involve much detailed and time consuming work but it has been demonstrated that the resulting reliability improvements lead to savings in service costs which more than offset the cost of the evaluation.

  20. From Prediction to Process

    DEFF Research Database (Denmark)

    Nielsen, Kristian Steensen

    2017-01-01

    and highlighting the relevance of self-regulation for environmental behavior change. The article focuses on the two primary components of self-regulation: goal setting and goal striving. Self-regulation research differs from the prediction models commonly employed in environmental research (e.g. theory of planned...... behavior or value-belief-norm theory), as it focuses on the dynamic psychological mechanisms that result in either success or failure in acting relative to a certain standard or goal. Similar to the intention-behavior gap, self-regulation research recognizes the occasional failure of people to adhere...... to their own environmental standards and goals. However, unlike prediction models, self-regulation research gives directions on how to reduce the frequency by which these failures occur....

  1. Predictability of Critical Transitions

    CERN Document Server

    Zhang, Xiaozhu; Hallerberg, Sarah

    2015-01-01

    Critical transitions in multistable systems have been discussed as models for a variety of phenomena ranging from the extinctions of species to socio-economic changes and climate transitions between ice-ages and warm-ages. From bifurcation theory we can expect certain critical transitions to be preceded by a decreased recovery from external perturbations. The consequences of this critical slowing down have been observed as an increase in variance and autocorrelation prior to the transition. However especially in the presence of noise it is not clear, whether these changes in observation variables are statistically relevant such that they could be used as indicators for critical transitions. In this contribution we investigate the predictability of critical transitions in conceptual models. We study the the quadratic integrate-and-fire model and the van der Pol model, under the influence of external noise. We focus especially on the statistical analysis of the success of predictions and the overall predictabil...

  2. Predicting Lotto Numbers

    DEFF Research Database (Denmark)

    Jørgensen, Claus Bjørn; Suetens, Sigrid; Tyran, Jean-Robert

    We investigate the “law of small numbers” using a unique panel data set on lotto gambling. Because we can track individual players over time, we can measure how they react to outcomes of recent lotto drawings. We can therefore test whether they behave as if they believe they can predict lotto...... numbers based on recent drawings. While most players pick the same set of numbers week after week without regards of numbers drawn or anything else, we find that those who do change, act on average in the way predicted by the law of small numbers as formalized in recent behavioral theory. In particular......, on average they move away from numbers that have recently been drawn, as suggested by the “gambler’s fallacy”, and move toward numbers that are on streak, i.e. have been drawn several weeks in a row, consistent with the “hot hand fallacy”....

  3. Urban pluvial flood prediction

    DEFF Research Database (Denmark)

    Thorndahl, Søren Liedtke; Nielsen, Jesper Ellerbæk; Jensen, David Getreuer

    2016-01-01

    Flooding produced by high-intensive local rainfall and drainage system capacity exceedance can have severe impacts in cities. In order to prepare cities for these types of flood events – especially in the future climate – it is valuable to be able to simulate these events numerically both...... historically and in real-time. There is a rather untested potential in real-time prediction of urban floods. In this paper radar data observations with different spatial and temporal resolution, radar nowcasts of 0–2 h lead time, and numerical weather models with lead times up to 24 h are used as inputs...... to an integrated flood and drainage systems model in order to investigate the relative difference between different inputs in predicting future floods. The system is tested on a small town Lystrup in Denmark, which has been flooded in 2012 and 2014. Results show it is possible to generate detailed flood maps...

  4. Predictive dynamic digital holography

    Science.gov (United States)

    Sulaiman, Sennan; Gibson, Steve; Spencer, Mark

    2016-09-01

    Digital holography has received recent attention for many imaging and sensing applications, including imaging through turbulent and turbid media, adaptive optics, three dimensional projective display technology and optical tweezing. A significant obstacle for digital holography in real-time applications, such as wavefront sensing for high energy laser systems and high speed imaging for target tracking, is the fact that digital holography is computationally intensive; it requires iterative virtual wavefront propagation and hill-climbing to optimize some sharpness criteria. This paper demonstrates real-time methods for digital holography based on approaches developed recently at UCLA for optimal and adaptive identification, prediction, and control of optical wavefronts. The methods presented integrate minimum variance wavefront prediction into digital holography schemes to short-circuit the computationally intensive algorithms for iterative propagation of virtual wavefronts and hill climbing for sharpness optimization.

  5. Comparing Spatial Predictions

    KAUST Repository

    Hering, Amanda S.

    2011-11-01

    Under a general loss function, we develop a hypothesis test to determine whether a significant difference in the spatial predictions produced by two competing models exists on average across the entire spatial domain of interest. The null hypothesis is that of no difference, and a spatial loss differential is created based on the observed data, the two sets of predictions, and the loss function chosen by the researcher. The test assumes only isotropy and short-range spatial dependence of the loss differential but does allow it to be non-Gaussian, non-zero-mean, and spatially correlated. Constant and nonconstant spatial trends in the loss differential are treated in two separate cases. Monte Carlo simulations illustrate the size and power properties of this test, and an example based on daily average wind speeds in Oklahoma is used for illustration. Supplemental results are available online. © 2011 American Statistical Association and the American Society for Qualitys.

  6. Predicting appointment breaking.

    Science.gov (United States)

    Bean, A G; Talaga, J

    1995-01-01

    The goal of physician referral services is to schedule appointments, but if too many patients fail to show up, the value of the service will be compromised. The authors found that appointment breaking can be predicted by the number of days to the scheduled appointment, the doctor's specialty, and the patient's age and gender. They also offer specific suggestions for modifying the marketing mix to reduce the incidence of no-shows.

  7. Nominal model predictive control

    OpenAIRE

    Grüne, Lars

    2013-01-01

    5 p., to appear in Encyclopedia of Systems and Control, Tariq Samad, John Baillieul (eds.); International audience; Model Predictive Control is a controller design method which synthesizes a sampled data feedback controller from the iterative solution of open loop optimal control problems.We describe the basic functionality of MPC controllers, their properties regarding feasibility, stability and performance and the assumptions needed in order to rigorously ensure these properties in a nomina...

  8. Prediction of Algebraic Instabilities

    Science.gov (United States)

    Zaretzky, Paula; King, Kristina; Hill, Nicole; Keithley, Kimberlee; Barlow, Nathaniel; Weinstein, Steven; Cromer, Michael

    2016-11-01

    A widely unexplored type of hydrodynamic instability is examined - large-time algebraic growth. Such growth occurs on the threshold of (exponentially) neutral stability. A new methodology is provided for predicting the algebraic growth rate of an initial disturbance, when applied to the governing differential equation (or dispersion relation) describing wave propagation in dispersive media. Several types of algebraic instabilities are explored in the context of both linear and nonlinear waves.

  9. Multivariate respiratory motion prediction

    Science.gov (United States)

    Dürichen, R.; Wissel, T.; Ernst, F.; Schlaefer, A.; Schweikard, A.

    2014-10-01

    In extracranial robotic radiotherapy, tumour motion is compensated by tracking external and internal surrogates. To compensate system specific time delays, time series prediction of the external optical surrogates is used. We investigate whether the prediction accuracy can be increased by expanding the current clinical setup by an accelerometer, a strain belt and a flow sensor. Four previously published prediction algorithms are adapted to multivariate inputs—normalized least mean squares (nLMS), wavelet-based least mean squares (wLMS), support vector regression (SVR) and relevance vector machines (RVM)—and evaluated for three different prediction horizons. The measurement involves 18 subjects and consists of two phases, focusing on long term trends (M1) and breathing artefacts (M2). To select the most relevant and least redundant sensors, a sequential forward selection (SFS) method is proposed. Using a multivariate setting, the results show that the clinically used nLMS algorithm is susceptible to large outliers. In the case of irregular breathing (M2), the mean root mean square error (RMSE) of a univariate nLMS algorithm is 0.66 mm and can be decreased to 0.46 mm by a multivariate RVM model (best algorithm on average). To investigate the full potential of this approach, the optimal sensor combination was also estimated on the complete test set. The results indicate that a further decrease in RMSE is possible for RVM (to 0.42 mm). This motivates further research about sensor selection methods. Besides the optical surrogates, the sensors most frequently selected by the algorithms are the accelerometer and the strain belt. These sensors could be easily integrated in the current clinical setup and would allow a more precise motion compensation.

  10. Characterization of Mesoscale Predictability

    Science.gov (United States)

    2013-09-30

    assimilation to either create pairs of different initial conditions (Bei and Zhang 2007, Mapes et al. 2008) or to initialize a large ensemble (Durran et...curves over all wave numbers where the error had not yet saturated. Following the terminology suggested by Mapes et al. (2008), the evolution of... Mapes , B., S. Tulich, T. Nasuno, and M. Satoh, 2008: Predictability aspects of global aqua- planet simulations with explicit convection. J. Meteor. Soc

  11. Nominal Model Predictive Control

    OpenAIRE

    Grüne, Lars

    2014-01-01

    5 p., to appear in Encyclopedia of Systems and Control, Tariq Samad, John Baillieul (eds.); International audience; Model Predictive Control is a controller design method which synthesizes a sampled data feedback controller from the iterative solution of open loop optimal control problems.We describe the basic functionality of MPC controllers, their properties regarding feasibility, stability and performance and the assumptions needed in order to rigorously ensure these properties in a nomina...

  12. Predictive Game Theory

    Science.gov (United States)

    Wolpert, David H.

    2005-01-01

    Probability theory governs the outcome of a game; there is a distribution over mixed strat.'s, not a single "equilibrium". To predict a single mixed strategy must use our loss function (external to the game's players. Provides a quantification of any strategy's rationality. Prove rationality falls as cost of computation rises (for players who have not previously interacted). All extends to games with varying numbers of players.

  13. Time-predictable architectures

    CERN Document Server

    Rochange, Christine; Uhrig , Sascha

    2014-01-01

    Building computers that can be used to design embedded real-time systems is the subject of this title. Real-time embedded software requires increasingly higher performances. The authors therefore consider processors that implement advanced mechanisms such as pipelining, out-of-order execution, branch prediction, cache memories, multi-threading, multicorearchitectures, etc. The authors of this book investigate the timepredictability of such schemes.

  14. Predicting Human Cooperation.

    Directory of Open Access Journals (Sweden)

    John J Nay

    Full Text Available The Prisoner's Dilemma has been a subject of extensive research due to its importance in understanding the ever-present tension between individual self-interest and social benefit. A strictly dominant strategy in a Prisoner's Dilemma (defection, when played by both players, is mutually harmful. Repetition of the Prisoner's Dilemma can give rise to cooperation as an equilibrium, but defection is as well, and this ambiguity is difficult to resolve. The numerous behavioral experiments investigating the Prisoner's Dilemma highlight that players often cooperate, but the level of cooperation varies significantly with the specifics of the experimental predicament. We present the first computational model of human behavior in repeated Prisoner's Dilemma games that unifies the diversity of experimental observations in a systematic and quantitatively reliable manner. Our model relies on data we integrated from many experiments, comprising 168,386 individual decisions. The model is composed of two pieces: the first predicts the first-period action using solely the structural game parameters, while the second predicts dynamic actions using both game parameters and history of play. Our model is successful not merely at fitting the data, but in predicting behavior at multiple scales in experimental designs not used for calibration, using only information about the game structure. We demonstrate the power of our approach through a simulation analysis revealing how to best promote human cooperation.

  15. 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.

  16. Kuiper Belt Occultation Predictions

    CERN Document Server

    Fraser, Wesley C; Trujillo, Chad; Stephens, Andrew W; Kavelaars, JJ; Brown, Michael E; Bianco, Federica B; Boyle, Richard P; Brucker, Melissa J; Hetherington, Nathan; Joner, Michael; Keel, William C; Langill, Phil P; Lister, Tim; McMillan, Russet J; Young, Leslie

    2013-01-01

    Here we present observations of 7 large Kuiper Belt Objects. From these observations, we extract a point source catalog with $\\sim0.01"$ precision, and astrometry of our target Kuiper Belt Objects with $0.04-0.08"$ precision within that catalog. We have developed a new technique to predict the future occurrence of stellar occultations by Kuiper Belt Objects. The technique makes use of a maximum likelihood approach which determines the best-fit adjustment to cataloged orbital elements of an object. Using simulations of a theoretical object, we discuss the merits and weaknesses of this technique compared to the commonly adopted ephemeris offset approach. We demonstrate that both methods suffer from separate weaknesses, and thus, together provide a fair assessment of the true uncertainty in a particular prediction. We present occultation predictions made by both methods for the 7 tracked objects, with dates as late as 2015. Finally, we discuss observations of three separate close passages of Quaoar to field star...

  17. Is Suicide Predictable?

    Directory of Open Access Journals (Sweden)

    S Asmaee

    2012-04-01

    Full Text Available Background:The current study aimed to test the hypothesis: Is suicide predictable? And try to classify the predictive factors in multiple suicide attempts.Methods:A cross-sectional study was administered to 223 multiple attempters, women who came to a medical poison centre after a suicide attempt.The participants were young, poor, and single.A Logistic Regression Analiysis was used to classify the predictive factors of suicide.Results:Women who had multiple suicide attempts exhibited a significant tendency to attempt suicide again. They had a history for more than two years of multiple suicide attempts, from three to as many as 18 times, plus mental illnesses such as depression and substance abuse.They also had a positive history of mental illnesses.Conclusion:Results indicate that contributing factors for another suicide attempt include previous suicide attempts, mental illness (depression,or a positive history of mental illnesses in the family affecting them at a young age, and substance abuse.

  18. An Analysis of Numerical Weather Prediction of the Diabatic Rossby Vortex

    Science.gov (United States)

    2014-06-01

    expected for a typical extratropical cyclone . These factors together are evidence of baroclinic conversion of APE to kinetic energy , as outlined above in...the observed lifecycle of a DRV associated with recurving tropical cyclone Chaba. An assessment of the control forecast indicated significant...The script is verified via an examination of the observed lifecycle of a DRV associated with recurving tropical cyclone Chaba. An assessment of the

  19. Prediction of resonant oscillation

    DEFF Research Database (Denmark)

    2010-01-01

    The invention relates to methods for prediction of parametric rolling of vessels. The methods are based on frequency domain and time domain information in order do set up a detector able to trigger an alarm when parametric roll is likely to occur. The methods use measurements of e.g. pitch and roll...... oscillations and compare the measured oscillations using FFT analysis of signal correlations, variance analysis of signals and other comparisons. As an example, the presence of a growing peak around a frequency that doubles the roll natural frequency indicates the possibility that parametric roll is going...

  20. Predicting Sustainable Work Behavior

    DEFF Research Database (Denmark)

    Hald, Kim Sundtoft

    2013-01-01

    Sustainable work behavior is an important issue for operations managers – it has implications for most outcomes of OM. This research explores the antecedents of sustainable work behavior. It revisits and extends the sociotechnical model developed by Brown et al. (2000) on predicting safe behavior....... Employee characteristics and general attitudes towards safety and work condition are included in the extended model. A survey was handed out to 654 employees in Chinese factories. This research contributes by demonstrating how employee- characteristics and general attitudes towards safety and work...... condition influence their sustainable work behavior. A new definition of sustainable work behavior is proposed....

  1. Foundations of predictive analytics

    CERN Document Server

    Wu, James

    2012-01-01

    Drawing on the authors' two decades of experience in applied modeling and data mining, Foundations of Predictive Analytics presents the fundamental background required for analyzing data and building models for many practical applications, such as consumer behavior modeling, risk and marketing analytics, and other areas. It also discusses a variety of practical topics that are frequently missing from similar texts. The book begins with the statistical and linear algebra/matrix foundation of modeling methods, from distributions to cumulant and copula functions to Cornish--Fisher expansion and o

  2. Consciousness -- A Verifiable Prediction

    Science.gov (United States)

    Panchapakesan, N.

    2014-07-01

    Consciousness may or may not be completely within the realm of science. We have argued elsewhere that there is a high probability that it is not within the purview of science, just like humanities and arts are outside science. Even social sciences do not come under science when human interactions are involved. Here, we suggest a possible experiment to decide whether it is part of science. We suggest that a scientific signal may be available to investigate the prediction in the form of an electromagnetic brainwave background radiation.

  3. Predicting Lotto Numbers

    DEFF Research Database (Denmark)

    Suetens, Sigrid; Galbo-Jørgensen, Claus B.; Tyran, Jean-Robert Karl

    2016-01-01

    as formalized in recent behavioral theory. In particular, players tend to bet less on numbers that have been drawn in the preceding week, as suggested by the ‘gambler’s fallacy’, and bet more on a number if it was frequently drawn in the recent past, consistent with the ‘hot-hand fallacy’.......We investigate the ‘law of small numbers’ using a data set on lotto gambling that allows us to measure players’ reactions to draws. While most players pick the same set of numbers week after week, we find that those who do change react on average as predicted by the law of small numbers...

  4. Epitope prediction methods

    DEFF Research Database (Denmark)

    Karosiene, Edita

    on machine learning techniques. Several MHC class I binding prediction algorithms have been developed and due to their high accuracy they are used by many immunologists to facilitate the conventional experimental process of epitope discovery. However, the accuracy of these methods depends on data defining...... the NetMHCIIpan-3.0 predictor based on artificial neural networks, which is capable of giving binding affinities to any human MHC class II molecule. Chapter 4 of this thesis gives an overview of bioinformatics tools developed by the Immunological Bioinformatics group at Center for Biological Sequence...

  5. Predicting photothermal field performance

    Science.gov (United States)

    Gonzalez, C. C.; Ross, R. G., Jr.

    1984-01-01

    Photothermal field performance in flat plate solar collectors was predicted. An analytical model which incorporates the measured dependency between transmittance loss and UV and temperature exposure levels was developed. The model uses SOLMET weather data extrapolated to 30 years for various sites and module mounting configurations. It is concluded that the temperature is the key to photothermally induced transmittance loss. The sensitivity of transmittance loss to UV level is nonlinear with minimum in curve near one sun. The ethylene vinyl acetate (EVA) results are consistent with 30 year life allocation.

  6. Towards Predictive Association Theories

    DEFF Research Database (Denmark)

    Kontogeorgis, Georgios; Tsivintzelis, Ioannis; Michelsen, Michael Locht

    2011-01-01

    Association equations of state like SAFT, CPA and NRHB have been previously applied to many complex mixtures. In this work we focus on two of these models, the CPA and the NRHB equations of state and the emphasis is on the analysis of their predictive capabilities for a wide range of applications...... and water–MEG–aliphatic hydrocarbons LLE using interaction parameters obtained from the binary data alone. Moreover, it is demonstrated that the NRHB equation of state is a versatile tool which can be employed equally well to mixtures with pharmaceuticals and solvents, including mixed solvents, as well...

  7. Chloride ingress prediction

    DEFF Research Database (Denmark)

    Frederiksen, Jens Mejer; Geiker, Mette Rica

    2008-01-01

    Prediction of chloride ingress into concrete is an important part of durability design of reinforced concrete structures exposed to chloride containing environment. This paper presents experimentally based design parameters for Portland cement concretes with and without silica fume and fly ash...... in marine atmospheric and submersed South Scandinavian environment. The design parameters are based on sequential measurements of 86 chloride profiles taken over ten years from 13 different types of concrete. The design parameters provide the input for an analytical model for chloride profiles as function...

  8. Predicting Lotto Numbers

    DEFF Research Database (Denmark)

    Suetens, Sigrid; Galbo-Jørgensen, Claus B.; Tyran, Jean-Robert Karl

    2016-01-01

    We investigate the ‘law of small numbers’ using a data set on lotto gambling that allows us to measure players’ reactions to draws. While most players pick the same set of numbers week after week, we find that those who do change react on average as predicted by the law of small numbers...... as formalized in recent behavioral theory. In particular, players tend to bet less on numbers that have been drawn in the preceding week, as suggested by the ‘gambler’s fallacy’, and bet more on a number if it was frequently drawn in the recent past, consistent with the ‘hot-hand fallacy’....

  9. Prediction of Biomolecular Complexes

    KAUST Repository

    Vangone, Anna

    2017-04-12

    Almost all processes in living organisms occur through specific interactions between biomolecules. Any dysfunction of those interactions can lead to pathological events. Understanding such interactions is therefore a crucial step in the investigation of biological systems and a starting point for drug design. In recent years, experimental studies have been devoted to unravel the principles of biomolecular interactions; however, due to experimental difficulties in solving the three-dimensional (3D) structure of biomolecular complexes, the number of available, high-resolution experimental 3D structures does not fulfill the current needs. Therefore, complementary computational approaches to model such interactions are necessary to assist experimentalists since a full understanding of how biomolecules interact (and consequently how they perform their function) only comes from 3D structures which provide crucial atomic details about binding and recognition processes. In this chapter we review approaches to predict biomolecular complexesBiomolecular complexes, introducing the concept of molecular dockingDocking, a technique which uses a combination of geometric, steric and energetics considerations to predict the 3D structure of a biological complex starting from the individual structures of its constituent parts. We provide a mini-guide about docking concepts, its potential and challenges, along with post-docking analysis and a list of related software.

  10. Predicting Alloreactivity in Transplantation

    Directory of Open Access Journals (Sweden)

    Kirsten Geneugelijk

    2014-01-01

    Full Text Available Human leukocyte Antigen (HLA mismatching leads to severe complications after solid-organ transplantation and hematopoietic stem-cell transplantation. The alloreactive responses underlying the posttransplantation complications include both direct recognition of allogeneic HLA by HLA-specific alloantibodies and T cells and indirect T-cell recognition. However, the immunogenicity of HLA mismatches is highly variable; some HLA mismatches lead to severe clinical B-cell- and T-cell-mediated alloreactivity, whereas others are well tolerated. Definition of the permissibility of HLA mismatches prior to transplantation allows selection of donor-recipient combinations that will have a reduced chance to develop deleterious host-versus-graft responses after solid-organ transplantation and graft-versus-host responses after hematopoietic stem-cell transplantation. Therefore, several methods have been developed to predict permissible HLA-mismatch combinations. In this review we aim to give a comprehensive overview about the current knowledge regarding HLA-directed alloreactivity and several developed in vitro and in silico tools that aim to predict direct and indirect alloreactivity.

  11. Predicting Microsurgical Aptitude.

    Science.gov (United States)

    Osborn, Heather A; Kuthubutheen, Jafri; Yao, Christopher; Chen, Joseph M; Lin, Vincent Y

    2015-08-01

    Microscopic techniques are an essential part of otolaryngologic practice. These procedures demand advanced psychomotor and visuospatial skills, and trainees possess these abilities to varying degrees. No method currently exists to predict who will possess an aptitude for microscopic surgery. Our goal was to determine whether performance can be predicted by background experiences or skills. Retrospective cohort study. Tertiary academic hospital. Students with no previous surgical experience. Subjects were surveyed on a wide range characteristics thought to affect surgical aptitude, with a primary focus on video gaming and musical training. Subjects performed a microsurgical task using a novel simulator and their performance was assessed by blinded investigators. Forty-six students were assessed. There was no correlation between video gaming and improved microsurgical performance. Rather, video gamers obtained worse scores, although this difference did not reach significance. The majority of students played a musical instrument. Within this group, musicians who began playing at younger ages obtained higher scores, with the highest scores obtained by musicians who began playing before age 6. However, musicians did not obtain higher scores than non-musicians, regardless of their age of initiation. No improvement in microsurgical aptitude was seen in subjects who had a history of video gaming or musical instrument playing.

  12. Energy Predictions 2011

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-10-15

    Even as the recession begins to subside, the energy sector is still likely to experience challenging conditions as we enter 2011. It should be remembered how very important a role energy plays in driving the global economy. Serving as a simple yet global and unified measure of economic recovery, it is oil's price range and the strength and sustainability of the recovery which will impact the ways in which all forms of energy are produced and consumed. The report aims for a closer insight into these predictions: What will happen with M and A (Mergers and Acquisitions) in the energy industry?; What are the prospects for renewables?; Will the water-energy nexus grow in importance?; How will technological leaps and bounds affect E and P (exploration and production) operations?; What about electric cars? This is the second year Deloitte's Global Energy and Resources Group has published its predictions for the year ahead. The report is based on in-depth interviews with clients, industry analysts, and senior energy practitioners from Deloitte member firms around the world.

  13. Theory use in social predictions.

    Science.gov (United States)

    Bazinger, Claudia; Kühberger, Anton

    2012-12-01

    In a commentary to our article on the role of theory and simulation in social predictions, Krueger (2012) argues that the role of theory is neglected in social psychology for a good reason. He considers evidence indicating that people readily generalize from themselves to others. In response, we stress the role of theoretical knowledge in predicting other people's behavior. Importantly, prediction by simulation and prediction by theory can lead to high as well as to low correlations between own and predicted behavior. This renders correlations largely useless for identifying the prediction strategy. We argue that prediction by theory is a serious alternative to prediction by simulation, and that reliance on correlation has led to a bias toward simulation.

  14. Theory use in social predictions

    OpenAIRE

    Bazinger, Claudia; Kühberger, Anton

    2012-01-01

    In a commentary to our article on the role of theory and simulation in social predictions, Krueger (2012) argues that the role of theory is neglected in social psychology for a good reason. He considers evidence indicating that people readily generalize from themselves to others. In response, we stress the role of theoretical knowledge in predicting other people’s behavior. Importantly, prediction by simulation and prediction by theory can lead to high as well as to low correlations between o...

  15. Protein docking prediction using predicted protein-protein interface

    Directory of Open Access Journals (Sweden)

    Li Bin

    2012-01-01

    Full Text Available Abstract Background Many important cellular processes are carried out by protein complexes. To provide physical pictures of interacting proteins, many computational protein-protein prediction methods have been developed in the past. However, it is still difficult to identify the correct docking complex structure within top ranks among alternative conformations. Results We present a novel protein docking algorithm that utilizes imperfect protein-protein binding interface prediction for guiding protein docking. Since the accuracy of protein binding site prediction varies depending on cases, the challenge is to develop a method which does not deteriorate but improves docking results by using a binding site prediction which may not be 100% accurate. The algorithm, named PI-LZerD (using Predicted Interface with Local 3D Zernike descriptor-based Docking algorithm, is based on a pair wise protein docking prediction algorithm, LZerD, which we have developed earlier. PI-LZerD starts from performing docking prediction using the provided protein-protein binding interface prediction as constraints, which is followed by the second round of docking with updated docking interface information to further improve docking conformation. Benchmark results on bound and unbound cases show that PI-LZerD consistently improves the docking prediction accuracy as compared with docking without using binding site prediction or using the binding site prediction as post-filtering. Conclusion We have developed PI-LZerD, a pairwise docking algorithm, which uses imperfect protein-protein binding interface prediction to improve docking accuracy. PI-LZerD consistently showed better prediction accuracy over alternative methods in the series of benchmark experiments including docking using actual docking interface site predictions as well as unbound docking cases.

  16. The KIAPS global NWP model development project at the Korea Institute of Atmospheric Prediction Systems (KIAPS.org)

    Science.gov (United States)

    Kim, Young-Joon; Shin, Dong-Wook; Jin, Emilia; Oh, Tae-Jin; Song, Hyo-Jong; Song, In-Sun

    2013-04-01

    A nine-year project to develop Korea's own global Numerical Weather Prediction (NWP) system was launched in 2011 by the Korea Meteorological Administration (KMA) with the total funding of about 100 million US dollars. For the task, the Korea Institute of Atmospheric Prediction Systems (KIAPS) was founded by KMA as an independent, non-profit organization. The project consists of three main stages. The first stage (2011-2013) is to set up the Institute, recruit researchers, lay out plans for the research and development, and design the basic structure and explore/develop core NWP technologies. The second stage (2014-2016) aims at developing the basic modules for the dynamical core, physical parameterizations and data assimilation systems as well as the applied module for the system framework and couplers to connect the basic modules and external models, respectively, in a systematic and efficient way. The third stage (2017-2019) is for validating the prototype NWP system built in stage 2, including necessary post-processing systems, by selecting/improving modules and refining/finalizing the system for operational use at KMA. KIAPS designed key modules for the dynamical core by adopting existing and/or developing new cores, and developed a barotropic model first and a baroclinic model later with code parallelization and optimization in mind. Various physical parameterization schemes, including those used operationally in NWP models as well as those developed by Korean scientists, are being evaluated and improved by using single-column and LES models, and explicit simulations, etc. The control variables for variational data assimilation systems, the testbeds for observational data pre-processing systems, have been designed, the linear models for a barotropic system have been constructed, and the modules for cost function minimization have been developed. The module framework, which is flexible for prognostic and diagnostic variables, is being developed, the I

  17. Motor degradation prediction methods

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, J.R.; Kelly, J.F.; Delzingaro, M.J.

    1996-12-01

    Motor Operated Valve (MOV) squirrel cage AC motor rotors are susceptible to degradation under certain conditions. Premature failure can result due to high humidity/temperature environments, high running load conditions, extended periods at locked rotor conditions (i.e. > 15 seconds) or exceeding the motor`s duty cycle by frequent starts or multiple valve stroking. Exposure to high heat and moisture due to packing leaks, pressure seal ring leakage or other causes can significantly accelerate the degradation. ComEd and Liberty Technologies have worked together to provide and validate a non-intrusive method using motor power diagnostics to evaluate MOV rotor condition and predict failure. These techniques have provided a quick, low radiation dose method to evaluate inaccessible motors, identify degradation and allow scheduled replacement of motors prior to catastrophic failures.

  18. Permeability prediction in chalks

    DEFF Research Database (Denmark)

    Alam, Mohammad Monzurul; Fabricius, Ida Lykke; Prasad, Manika

    2011-01-01

    The velocity of elastic waves is the primary datum available for acquiring information about subsurface characteristics such as lithology and porosity. Cheap and quick (spatial coverage, ease of measurement) information of permeability can be achieved, if sonic velocity is used for permeability....... The relationships between permeability and porosity from core data were first examined using Kozeny’s equation. The data were analyzed for any correlations to the specific surface of the grain, Sg, and to the hydraulic property defined as the flow zone indicator (FZI). These two methods use two different approaches...... to enhance permeability prediction fromKozeny’s equation. The FZI is based on a concept of a tortuous flow path in a granular bed. The Sg concept considers the pore space that is exposed to fluid flow and models permeability resulting from effective flow parallel to pressure drop. The porosity-permeability...

  19. Essays on Earnings Predictability

    DEFF Research Database (Denmark)

    Bruun, Mark

    affect the accuracy of analysts´earnings forecasts. Finally, the objective of the dissertation is to investigate how the stock market is affected by the accuracy of corporate earnings projections. The dissertation contributes to a deeper understanding of these issues. First, it is shown how earnings...... forecasts can be generated based on historical timeseries patterns of financial ratios. This is done by modeling the return on equity and the growth-rate in equity as two separate but correlated timeseries processes which converge to a long-term, constant level. Empirical results suggest that these earnings...... of analysts’ earnings forecasts. Furthermore, the dissertation shows how the stock market’s reaction to the disclosure of information about corporate earnings depends on how well corporate earnings can be predicted. The dissertation indicates that the stock market’s reaction to the disclosure of earnings...

  20. Requirements for Predictive Analytics

    Energy Technology Data Exchange (ETDEWEB)

    Troy Hiltbrand

    2012-03-01

    It is important to have a clear understanding of how traditional Business Intelligence (BI) and analytics are different and how they fit together in optimizing organizational decision making. With tradition BI, activities are focused primarily on providing context to enhance a known set of information through aggregation, data cleansing and delivery mechanisms. As these organizations mature their BI ecosystems, they achieve a clearer picture of the key performance indicators signaling the relative health of their operations. Organizations that embark on activities surrounding predictive analytics and data mining go beyond simply presenting the data in a manner that will allow decisions makers to have a complete context around the information. These organizations generate models based on known information and then apply other organizational data against these models to reveal unknown information.

  1. Predictive coarse-graining

    Science.gov (United States)

    Schöberl, Markus; Zabaras, Nicholas; Koutsourelakis, Phaedon-Stelios

    2017-03-01

    We propose a data-driven, coarse-graining formulation in the context of equilibrium statistical mechanics. In contrast to existing techniques which are based on a fine-to-coarse map, we adopt the opposite strategy by prescribing a probabilistic coarse-to-fine map. This corresponds to a directed probabilistic model where the coarse variables play the role of latent generators of the fine scale (all-atom) data. From an information-theoretic perspective, the framework proposed provides an improvement upon the relative entropy method [1] and is capable of quantifying the uncertainty due to the information loss that unavoidably takes place during the coarse-graining process. Furthermore, it can be readily extended to a fully Bayesian model where various sources of uncertainties are reflected in the posterior of the model parameters. The latter can be used to produce not only point estimates of fine-scale reconstructions or macroscopic observables, but more importantly, predictive posterior distributions on these quantities. Predictive posterior distributions reflect the confidence of the model as a function of the amount of data and the level of coarse-graining. The issues of model complexity and model selection are seamlessly addressed by employing a hierarchical prior that favors the discovery of sparse solutions, revealing the most prominent features in the coarse-grained model. A flexible and parallelizable Monte Carlo - Expectation-Maximization (MC-EM) scheme is proposed for carrying out inference and learning tasks. A comparative assessment of the proposed methodology is presented for a lattice spin system and the SPC/E water model.

  2. Data-Based Predictive Control with Multirate Prediction Step

    Science.gov (United States)

    Barlow, Jonathan S.

    2010-01-01

    Data-based predictive control is an emerging control method that stems from Model Predictive Control (MPC). MPC computes current control action based on a prediction of the system output a number of time steps into the future and is generally derived from a known model of the system. Data-based predictive control has the advantage of deriving predictive models and controller gains from input-output data. Thus, a controller can be designed from the outputs of complex simulation code or a physical system where no explicit model exists. If the output data happens to be corrupted by periodic disturbances, the designed controller will also have the built-in ability to reject these disturbances without the need to know them. When data-based predictive control is implemented online, it becomes a version of adaptive control. One challenge of MPC is computational requirements increasing with prediction horizon length. This paper develops a closed-loop dynamic output feedback controller that minimizes a multi-step-ahead receding-horizon cost function with multirate prediction step. One result is a reduced influence of prediction horizon and the number of system outputs on the computational requirements of the controller. Another result is an emphasis on portions of the prediction window that are sampled more frequently. A third result is the ability to include more outputs in the feedback path than in the cost function.

  3. Emerging approaches in predictive toxicology.

    Science.gov (United States)

    Zhang, Luoping; McHale, Cliona M; Greene, Nigel; Snyder, Ronald D; Rich, Ivan N; Aardema, Marilyn J; Roy, Shambhu; Pfuhler, Stefan; Venkatactahalam, Sundaresan

    2014-12-01

    Predictive toxicology plays an important role in the assessment of toxicity of chemicals and the drug development process. While there are several well-established in vitro and in vivo assays that are suitable for predictive toxicology, recent advances in high-throughput analytical technologies and model systems are expected to have a major impact on the field of predictive toxicology. This commentary provides an overview of the state of the current science and a brief discussion on future perspectives for the field of predictive toxicology for human toxicity. Computational models for predictive toxicology, needs for further refinement and obstacles to expand computational models to include additional classes of chemical compounds are highlighted. Functional and comparative genomics approaches in predictive toxicology are discussed with an emphasis on successful utilization of recently developed model systems for high-throughput analysis. The advantages of three-dimensional model systems and stem cells and their use in predictive toxicology testing are also described.

  4. Earthquake prediction with electromagnetic phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Hayakawa, Masashi, E-mail: hayakawa@hi-seismo-em.jp [Hayakawa Institute of Seismo Electomagnetics, Co. Ltd., University of Electro-Communications (UEC) Incubation Center, 1-5-1 Chofugaoka, Chofu Tokyo, 182-8585 (Japan); Advanced Wireless & Communications Research Center, UEC, Chofu Tokyo (Japan); Earthquake Analysis Laboratory, Information Systems Inc., 4-8-15, Minami-aoyama, Minato-ku, Tokyo, 107-0062 (Japan); Fuji Security Systems. Co. Ltd., Iwato-cho 1, Shinjyuku-ku, Tokyo (Japan)

    2016-02-01

    Short-term earthquake (EQ) prediction is defined as prospective prediction with the time scale of about one week, which is considered to be one of the most important and urgent topics for the human beings. If this short-term prediction is realized, casualty will be drastically reduced. Unlike the conventional seismic measurement, we proposed the use of electromagnetic phenomena as precursors to EQs in the prediction, and an extensive amount of progress has been achieved in the field of seismo-electromagnetics during the last two decades. This paper deals with the review on this short-term EQ prediction, including the impossibility myth of EQs prediction by seismometers, the reason why we are interested in electromagnetics, the history of seismo-electromagnetics, the ionospheric perturbation as the most promising candidate of EQ prediction, then the future of EQ predictology from two standpoints of a practical science and a pure science, and finally a brief summary.

  5. Predictive Maturity of Multi-Scale Simulation Models for Fuel Performance

    Energy Technology Data Exchange (ETDEWEB)

    Atamturktur, Sez [Clemson Univ., SC (United States); Unal, Cetin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hemez, Francois [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Williams, Brian [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tome, Carlos [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-03-16

    The project proposed to provide a Predictive Maturity Framework with its companion metrics that (1) introduce a formalized, quantitative means to communicate information between interested parties, (2) provide scientifically dependable means to claim completion of Validation and Uncertainty Quantification (VU) activities, and (3) guide the decision makers in the allocation of Nuclear Energy’s resources for code development and physical experiments. The project team proposed to develop this framework based on two complimentary criteria: (1) the extent of experimental evidence available for the calibration of simulation models and (2) the sophistication of the physics incorporated in simulation models. The proposed framework is capable of quantifying the interaction between the required number of physical experiments and degree of physics sophistication. The project team has developed this framework and implemented it with a multi-scale model for simulating creep of a core reactor cladding. The multi-scale model is composed of the viscoplastic self-consistent (VPSC) code at the meso-scale, which represents the visco-plastic behavior and changing properties of a highly anisotropic material and a Finite Element (FE) code at the macro-scale to represent the elastic behavior and apply the loading. The framework developed takes advantage of the transparency provided by partitioned analysis, where independent constituent codes are coupled in an iterative manner. This transparency allows model developers to better understand and remedy the source of biases and uncertainties, whether they stem from the constituents or the coupling interface by exploiting separate-effect experiments conducted within the constituent domain and integral-effect experiments conducted within the full-system domain. The project team has implemented this procedure with the multi- scale VPSC-FE model and demonstrated its ability to improve the predictive capability of the model. Within this

  6. Protein Chemical Shift Prediction

    CERN Document Server

    Larsen, Anders S

    2014-01-01

    The protein chemical shifts holds a large amount of information about the 3-dimensional structure of the protein. A number of chemical shift predictors based on the relationship between structures resolved with X-ray crystallography and the corresponding experimental chemical shifts have been developed. These empirical predictors are very accurate on X-ray structures but tends to be insensitive to small structural changes. To overcome this limitation it has been suggested to make chemical shift predictors based on quantum mechanical(QM) calculations. In this thesis the development of the QM derived chemical shift predictor Procs14 is presented. Procs14 is based on 2.35 million density functional theory(DFT) calculations on tripeptides and contains corrections for hydrogen bonding, ring current and the effect of the previous and following residue. Procs14 is capable at performing predictions for the 13CA, 13CB, 13CO, 15NH, 1HN and 1HA backbone atoms. In order to benchmark Procs14, a number of QM NMR calculatio...

  7. Predictive Food Microbiology

    DEFF Research Database (Denmark)

    Østergaard, Nina Bjerre

    Listeria monocytogenes is a well-known food borne pathogen that potentially causes listeriosis. No outbreaks or cases of listeriosis have been associated with cottage cheese, but several confirmed cases and outbreaks in the EU and the US have been related to dairy products made from raw or pasteu......Listeria monocytogenes is a well-known food borne pathogen that potentially causes listeriosis. No outbreaks or cases of listeriosis have been associated with cottage cheese, but several confirmed cases and outbreaks in the EU and the US have been related to dairy products made from raw...... or pasteurised milk. This, in combination with the fact that cottage cheese support growth of Listeria monocytogenes, induces a documentation requirement on the food producer. In the EU regulatory framework, mathematical models are recognised as a suitable supplement to traditional microbiological methods...... of the present PhD-project is thought to be important in relation to the development of predictive models that are valuable for, and readily applicable in the food industry....

  8. Predicting happiness among centenarians.

    Science.gov (United States)

    Bishop, Alex J; Martin, Peter; MacDonald, Maurice; Poon, Leonard; Jazwinski, S M; Green, R C; Gearing, M; Markesbery, W R; Woodard, J L; Johnson, M A; Tenover, J S; Siegler, I C; Rodgers, W L; Hausman, D B; Rott, C; Davey, A; Arnold, J

    2010-01-01

    Happiness is believed to evolve from the comparison of current circumstances relative to past achievement. However, gerontological literature on happiness in extreme old age has been limited. The purpose of this study was to determine how perceptions of health, social provisions, and economics link past satisfaction with life to current feelings of happiness among persons living to 100 years of age and beyond. A total of 158 centenarians from the Georgia Centenarian Study were included to conduct the investigation. Items reflecting congruence and happiness from the Life Satisfaction Index were used to evaluate a model of happiness. Pathways between congruence, perceived economic security, subjective health, perceived social provisions, and happiness were analyzed using structural equation modeling. Congruence emerged as a key predictor of happiness. Furthermore, congruence predicted perceived economic security and subjective health, whereas perceived economic security had a strong influence on subjective health status. It appears that past satisfaction with life influences how centenarians frame subjective evaluations of health status and economic security. Furthermore, past satisfaction with life is directly associated with present happiness. This presents implications relative to understanding how perception of resources may enhance quality of life among persons who live exceptionally long lives. Copyright 2010 S. Karger AG, Basel.

  9. Useful theories make predictions.

    Science.gov (United States)

    Howes, Andrew

    2012-01-01

    Stephen and Van Orden (this issue) propose that there is a complex system approach to cognitive science, and collectively the authors of the papers presented in this issue believe that this approach provides the means to drive a revolution in the science of the mind. Unfortunately, however illuminating, this explanation is absent and hyperbole is all too extensive. In contrast, I argue (1) that dynamic systems theory is not new to cognitive science and does not provide a basis for a revolution, (2) it is not necessary to reject cognitive science in order to explain the constraints imposed by the body and the environment, (3) it is not necessary, as Silberstein and Chemero (this issue) appear to do, to reject cognitive science in order to explain consciousness, and (4) our understanding of pragmatics is not advanced by Gibbs and Van Orden's (this issue) "self-organized criticality".? Any debate about the future of cognitive science could usefully focus on predictive adequacy. Unfortunately, this is not the approach taken by the authors of this issue.

  10. Melanoma risk prediction models

    Directory of Open Access Journals (Sweden)

    Nikolić Jelena

    2014-01-01

    Full Text Available Background/Aim. The lack of effective therapy for advanced stages of melanoma emphasizes the importance of preventive measures and screenings of population at risk. Identifying individuals at high risk should allow targeted screenings and follow-up involving those who would benefit most. The aim of this study was to identify most significant factors for melanoma prediction in our population and to create prognostic models for identification and differentiation of individuals at risk. Methods. This case-control study included 697 participants (341 patients and 356 controls that underwent extensive interview and skin examination in order to check risk factors for melanoma. Pairwise univariate statistical comparison was used for the coarse selection of the most significant risk factors. These factors were fed into logistic regression (LR and alternating decision trees (ADT prognostic models that were assessed for their usefulness in identification of patients at risk to develop melanoma. Validation of the LR model was done by Hosmer and Lemeshow test, whereas the ADT was validated by 10-fold cross-validation. The achieved sensitivity, specificity, accuracy and AUC for both models were calculated. The melanoma risk score (MRS based on the outcome of the LR model was presented. Results. The LR model showed that the following risk factors were associated with melanoma: sunbeds (OR = 4.018; 95% CI 1.724- 9.366 for those that sometimes used sunbeds, solar damage of the skin (OR = 8.274; 95% CI 2.661-25.730 for those with severe solar damage, hair color (OR = 3.222; 95% CI 1.984-5.231 for light brown/blond hair, the number of common naevi (over 100 naevi had OR = 3.57; 95% CI 1.427-8.931, the number of dysplastic naevi (from 1 to 10 dysplastic naevi OR was 2.672; 95% CI 1.572-4.540; for more than 10 naevi OR was 6.487; 95%; CI 1.993-21.119, Fitzpatricks phototype and the presence of congenital naevi. Red hair, phototype I and large congenital naevi were

  11. Predicting the unpredictable.

    Science.gov (United States)

    Bonabeau, Eric

    2002-03-01

    The collective behavior of people in crowds, markets, and organizations has long been a mystery. Why, for instance, do employee bonuses sometimes lead to decreases in productivity? Why do some products generate tremendous buzz, seemingly out of nowhere, while others languish despite multimillion-dollar marketing campaigns? How could a simple clerical error snowball into a catastrophic loss that bankrupts a financial institution? Traditional approaches like spreadsheet and regression analyses have failed to explain such "emergent phenomena," says Eric Bonabeau, because they work from the top down, trying to apply global equations and frameworks to a particular situation. But the behavior of emergent phenomena, contends Bonabeau, is formed from the bottom up--starting with the local interactions of individuals who alter their actions in response to other participants. Together, the myriad interactions result in a group behavior that can easily elude any top-down analysis. But now, thanks to "agent-based modeling," some companies are finding ways to analyze--and even predict--emergent phenomena. Macy's, for instance, has used the technology to investigate better ways to design its department stores. Hewlett-Packard has run agent-based simulations to anticipate how changes in its hiring strategy would affect its corporate culture. And Société Générale has used the technology to determine the operational risk of its asset management group. This article discusses emergent phenomena in detail and explains why they have become more prevalent in recent years. In addition to providing real-world examples of companies that have improved their business practices through agent-based modeling, Bonabeau also examines the future of this technology and points to several fields that may be revolutionized by its use.

  12. Predictions From Eternal Inflation

    Science.gov (United States)

    Leichenauer, Stefan

    We investigate the physics of eternal inflation, particularly the use of multiverse ideas to explain the observed values of the cosmological constant and the coincidences of cosmological timescales. We begin by reviewing eternal inflation, the multiverse, and the resulting measure problem. Then follows a detailed study of proposals to solve the measure problem, both analytical and numerical, including an analysis of their predictions for cosmological observables. A key outcome of this investigation is that the traditional anthropic calculations, which take into account the necessity of galaxies and heavy elements to produce observers, are redundant in our framework. The cosmological coincidence problem, the seemingly coincidental equality of the timescales of observation and of vacuum domination, is solved for the first time without appeal to detailed anthropic assumptions: very general geometric considerations do the job automatically. We also estimate a 10% likelihood that evidence for eternal inflation will be found in upcoming measurements of the energy density of the universe. Encouraged by this success, we go on to construct a modified version of the light-cone time measure which has conceptual advantages but also reproduces the phenomenology of its predecessor. We complete our study of the measure problem by noting that for a wide class of proposed solutions, including the one developed here, there is an implicit assumption being made about a catastrophic end to the universe. Finally, as a by-product of this research program we find geometries which violate some of the accepted common knowledge on holographic entropy bounds. We point this out and conjecture a general result.

  13. Networked and Distributed Predictive Control

    CERN Document Server

    Christofides, Panagiotis D; De La Pena, David Munoz

    2011-01-01

    "Networked and Distributed Predictive Control" presents rigorous, yet practical, methods for the design of networked and distributed predictive control systems - the first book to do so. The design of model predictive control systems using Lyapunov-based techniques accounting for the influence of asynchronous and delayed measurements is followed by a treatment of networked control architecture development. This shows how networked control can augment dedicated control systems in a natural way and takes advantage of additional, potentially asynchronous and delayed measurements to main

  14. Predictive regressions for macroeconomic data

    OpenAIRE

    Fukang Zhu; Zongwu Cai; Liang Peng

    2014-01-01

    Researchers have constantly asked whether stock returns can be predicted by some macroeconomic data. However, it is known that macroeconomic data may exhibit nonstationarity and/or heavy tails, which complicates existing testing procedures for predictability. In this paper we propose novel empirical likelihood methods based on some weighted score equations to test whether the monthly CRSP value-weighted index can be predicted by the log dividend-price ratio or the log earnings-price ratio. Th...

  15. Risk prediction for invasive candidiasis

    Directory of Open Access Journals (Sweden)

    Armin Ahmed

    2014-01-01

    Full Text Available Over past few years, treatment of invasive candidiasis (IC has evolved from targeted therapy to prophylaxis, pre-emptive and empirical therapy. Numerous predisposing factors for IC have been grouped together in various combinations to design risk prediction models. These models in general have shown good negative predictive value, but poor positive predictive value. They are useful in selecting the population which is less likely to benefit from empirical antifungal therapy and thus prevent overuse of antifungal agents. Current article deals with various risk prediction models for IC and their external validation studies.

  16. Risk prediction for invasive candidiasis.

    Science.gov (United States)

    Ahmed, Armin; Azim, Afzal; Baronia, Arvind Kumar; Marak, K Rungmei S K; Gurjar, Mohan

    2014-10-01

    Over past few years, treatment of invasive candidiasis (IC) has evolved from targeted therapy to prophylaxis, pre-emptive and empirical therapy. Numerous predisposing factors for IC have been grouped together in various combinations to design risk prediction models. These models in general have shown good negative predictive value, but poor positive predictive value. They are useful in selecting the population which is less likely to benefit from empirical antifungal therapy and thus prevent overuse of antifungal agents. Current article deals with various risk prediction models for IC and their external validation studies.

  17. Predictability of Forced Lorenz Systems

    Science.gov (United States)

    Li, Baosheng; Ding, Ruiqiang; Li, Jianping; Zhong, Quanjia

    2017-04-01

    Based on the nonlinear local Lyapunov exponent (NLLE) approach, the influences of external forcing on the predictability are studied in the Lorenz systems with constant and quasi-periodic forces in this paper. The results indicate that for the Lorenz systems with constant and quasi-periodic forces, their predictability limits increase with the forcing strength. With the same magnitude and different directions, the constant or quasi-periodic forcing shows different effects on the predictability limit in the Lorenz system, and these effects become significant with the increase of the forcing strength. Generally speaking, the positive forcing leads to a higher predictability limit than the negative forcing. Therefore, when we think about the effects of positive and negative elements and phases in the atmosphere and ocean research, the predictability problems driven by different phases should be considered separately. In addition, the influences of constant and quasi-periodic forces on the predictability are different in the Lorenz system. The effect of the constant forcing on the predictability is mainly reflected in the linear phase of error growth, while the nonlinear phase should also be considered for the situation of the quasi-periodic forcing. The predictability limit of the system under constant forcing is longer than the system under quasi-periodic forcing. These results based on simple chaotic model could provide insight into the studies of the actual atmosphere predictability.

  18. Total Ozone Prediction: Stratospheric Dynamics

    Science.gov (United States)

    Jackman, Charles H.; Kawa, S. Ramdy; Douglass, Anne R.

    2003-01-01

    The correct prediction of total ozone as a function of latitude and season is extremely important for global models. This exercise tests the ability of a particular model to simulate ozone. The ozone production (P) and loss (L) will be specified from a well- established global model and will be used in all GCMs for subsequent prediction of ozone. This is the "B-3 Constrained Run" from M&MII. The exercise mostly tests a model stratospheric dynamics in the prediction of total ozone. The GCM predictions will be compared and contrasted with TOMS measurements.

  19. Solar Cycle Predictions (Invited Review)

    Science.gov (United States)

    Pesnell, W. Dean

    2012-11-01

    Solar cycle predictions are needed to plan long-term space missions, just as weather predictions are needed to plan the launch. Fleets of satellites circle the Earth collecting many types of science data, protecting astronauts, and relaying information. All of these satellites are sensitive at some level to solar cycle effects. Predictions of drag on low-Earth orbit spacecraft are one of the most important. Launching a satellite with less propellant can mean a higher orbit, but unanticipated solar activity and increased drag can make that a Pyrrhic victory as the reduced propellant load is consumed more rapidly. Energetic events at the Sun can produce crippling radiation storms that endanger all assets in space. Solar cycle predictions also anticipate the shortwave emissions that cause degradation of solar panels. Testing solar dynamo theories by quantitative predictions of what will happen in 5 - 20 years is the next arena for solar cycle predictions. A summary and analysis of 75 predictions of the amplitude of the upcoming Solar Cycle 24 is presented. The current state of solar cycle predictions and some anticipations of how those predictions could be made more accurate in the future are discussed.

  20. A tutorial on conformal prediction

    CERN Document Server

    Shafer, Glenn

    2007-01-01

    Conformal prediction uses past experience to determine precise levels of confidence in new predictions. Given an error probability $\\epsilon$, together with a method that makes a prediction $\\hat{y}$ of a label $y$, it produces a set of labels, typically containing $\\hat{y}$, that also contains $y$ with probability $1-\\epsilon$. Conformal prediction can be applied to any method for producing $\\hat{y}$: a nearest-neighbor method, a support-vector machine, ridge regression, etc. Conformal prediction is designed for an on-line setting in which labels are predicted successively, each one being revealed before the next is predicted. The most novel and valuable feature of conformal prediction is that if the successive examples are sampled independently from the same distribution, then the successive predictions will be right $1-\\epsilon$ of the time, even though they are based on an accumulating dataset rather than on independent datasets. In addition to the model under which successive examples are sampled indepen...

  1. Prediction based on mean subset

    DEFF Research Database (Denmark)

    Øjelund, Henrik; Brown, P. J.; Madsen, Henrik;

    2002-01-01

    , it is found that the proposed mean subset method has superior prediction performance than prediction based on the best subset method, and in some settings also better than the ridge regression and lasso methods. The conclusions drawn from the Monte Carlo study is corroborated in an example in which prediction......Shrinkage methods have traditionally been applied in prediction problems. In this article we develop a shrinkage method (mean subset) that forms an average of regression coefficients from individual subsets of the explanatory variables. A Bayesian approach is taken to derive an expression of how...

  2. Predicting Marital Success with PREPARE: A Predictive Validity Study.

    Science.gov (United States)

    Fowers, Blaine J.; Olson, David H.

    1986-01-01

    Assessed the utility of the premarital inventory, PREPARE, in predicting marital success. Conducted a three-year follow-up study with couples (N=164) who took PREPARE during their engagement. Found that the PREPARE scores from three months before marriage could predict with 80-90% accuracy which couples were separated and divorced from those that…

  3. PREDICT : model for prediction of survival in localized prostate cancer

    NARCIS (Netherlands)

    Kerkmeijer, Linda G W; Monninkhof, Evelyn M.; van Oort, Inge M.; van der Poel, Henk G.; de Meerleer, Gert; van Vulpen, Marco

    2016-01-01

    Purpose: Current models for prediction of prostate cancer-specific survival do not incorporate all present-day interventions. In the present study, a pre-treatment prediction model for patients with localized prostate cancer was developed.Methods: From 1989 to 2008, 3383 patients were treated with I

  4. Predictability and Prediction for an Experimental Cultural Market

    Science.gov (United States)

    Colbaugh, Richard; Glass, Kristin; Ormerod, Paul

    Individuals are often influenced by the behavior of others, for instance because they wish to obtain the benefits of coordinated actions or infer otherwise inaccessible information. In such situations this social influence decreases the ex ante predictability of the ensuing social dynamics. We claim that, interestingly, these same social forces can increase the extent to which the outcome of a social process can be predicted very early in the process. This paper explores this claim through a theoretical and empirical analysis of the experimental music market described and analyzed in [1]. We propose a very simple model for this music market, assess the predictability of market outcomes through formal analysis of the model, and use insights derived through this analysis to develop algorithms for predicting market share winners, and their ultimate market shares, in the very early stages of the market. The utility of these predictive algorithms is illustrated through analysis of the experimental music market data sets [2].

  5. Predictive Manufacturing: A Classification Strategy to Predict Product Failures

    DEFF Research Database (Denmark)

    Khan, Abdul Rauf; Schiøler, Henrik; Kulahci, Murat

    2017-01-01

    Predicting failures can be considered a meaningful insight for the optimal planning of an industrial manufacturing process. In this era of advanced sensor technologies, when the collection of data from each step of the manufacturing process is common practice and advanced analytical skills enable...... us to efficiently analyze heterogeneous data streams, predicting failure becomes an achievable task. In this article: first, we propose a data mining strategy to deal with heterogeneous streams of data to predict failures in the production process; second, we aim to build a novel predictive...... manufacturing analytics model that employs a big data approach to predicting product failures; third, we illustrate the issue of high dimensionality, along with statistically redundant information; and, finally, our proposed method will be compared against the well-known classification methods (SVM, K...

  6. Macro-scale deformation behavior and characterization of deformation mechanisms below µm-scale in experimentally deformed Boom Clay by using the combination of triaxial compression, X-ray µ-CT imaging, DIC, BIB cross sectioning, and SEM

    Science.gov (United States)

    Oelker, Anne; Desbois, Guillaume; Urai, Janos L.; Bésuelle, Pierre; Viggiani, Gioacchino; Levasseur, Séverine

    2017-04-01

    Boom Clay is one formation being studied in Belgium as a potential host rock for deep geological disposal of radioactive waste. This poorly indurated clay presents in its natural state favorable properties against the migration of radionuclides: low permeability, low solute diffusion rates, good retention and sorption capacity for many radionuclides and good self-sealing capacity. During construction of disposal galleries, stress redistribution will lead to perturbation of the clay and the formation around galleries of the so-called "Excavation disturbed Zone" (EdZ). The study of deformation mechanisms and evolution of Boom Clay properties at macro but also micro scale allows to assess in a more mechanistic way the evolution of Boom Clay properties in this EdZ. In this work, we show microstructural investigations of Boom Clay deformed in undrained triaxial compression by linking conventional stress/strain curves with Digital Image Correlation (DIC) and scanning electron microscopy (SEM) imaging of broad-ion-beam (BIB) milled cross-sections to deduce deformation mechanisms based on microstructures at sub-micron resolution. Two specimens, collected in Mol (Belgium) at the European Underground Laboratories (URL) on HADES level, were analyzed: The major principal stress σ1 was applied parallel as well as perpendicular to the bedding direction with an initial mean normal effective stress of 4.5 MPa and an initial pore water pressure of 2.3 MPa, which are equal to the in-situ values. Linking the resulting DIC-derived maps of incremental strains with the corresponding stress/strain curve give not only information about the moment of the shear band development, but also on the way strain evolves within the specimen throughout the rest. Incremental DIC analysis of X-ray tomographic scans performed during loading tests give a time evolution of the strain field, and subsequently allow to detect strain localization which appears close to the stress peak. Regions with a comparable high and low shear strain were chosen and prepared for BIB-SEM investigations. In this case, shear bands show typical characteristics of uncemented small-grained clay-rich materials deformed at high shear strains including anastomosing shears. At nano-scale, the preferential orientation of clay particles in the anastomosing shears are construed to be responsible for the shear weakness. In addition, the reorientation of clay particles during the deformation leads to the strong reduction of porosity in the shear band. Ductile deformation mechanisms represented by grain-rotation, grain-sliding, bending, and granular flow are strongly involved for the development of the shear band.

  7. Predicting epileptic seizures in advance.

    Directory of Open Access Journals (Sweden)

    Negin Moghim

    Full Text Available Epilepsy is the second most common neurological disorder, affecting 0.6-0.8% of the world's population. In this neurological disorder, abnormal activity of the brain causes seizures, the nature of which tend to be sudden. Antiepileptic Drugs (AEDs are used as long-term therapeutic solutions that control the condition. Of those treated with AEDs, 35% become resistant to medication. The unpredictable nature of seizures poses risks for the individual with epilepsy. It is clearly desirable to find more effective ways of preventing seizures for such patients. The automatic detection of oncoming seizures, before their actual onset, can facilitate timely intervention and hence minimize these risks. In addition, advance prediction of seizures can enrich our understanding of the epileptic brain. In this study, drawing on the body of work behind automatic seizure detection and prediction from digitised Invasive Electroencephalography (EEG data, a prediction algorithm, ASPPR (Advance Seizure Prediction via Pre-ictal Relabeling, is described. ASPPR facilitates the learning of predictive models targeted at recognizing patterns in EEG activity that are in a specific time window in advance of a seizure. It then exploits advanced machine learning coupled with the design and selection of appropriate features from EEG signals. Results, from evaluating ASPPR independently on 21 different patients, suggest that seizures for many patients can be predicted up to 20 minutes in advance of their onset. Compared to benchmark performance represented by a mean S1-Score (harmonic mean of Sensitivity and Specificity of 90.6% for predicting seizure onset between 0 and 5 minutes in advance, ASPPR achieves mean S1-Scores of: 96.30% for prediction between 1 and 6 minutes in advance, 96.13% for prediction between 8 and 13 minutes in advance, 94.5% for prediction between 14 and 19 minutes in advance, and 94.2% for prediction between 20 and 25 minutes in advance.

  8. Crystal plasticity modeling of through-thickness texture heterogeneity in heavily rolled aluminum

    DEFF Research Database (Denmark)

    Delannay, Laurent; Mishin, Oleg V.

    2013-01-01

    The textures measured at different depths inside a cold rolled aluminium sheet are compared to results obtained by crystal plasticity predictions. Different assumptions about the micro-to-macro scale transitions are considered. The input texture reveals a through-thickness gradient that originate...

  9. Smeared crack modelling approach for corrosion-induced concrete damage

    DEFF Research Database (Denmark)

    Thybo, Anna Emilie Anusha; Michel, Alexander; Stang, Henrik

    2017-01-01

    compared to experimental data obtained by digital image correlation and published in the literature. Excellent agreements between experimentally observed and numerically predicted crack patterns at the micro and macro scale indicate the capability of the modelling approach to accurately capture corrosion...

  10. Predicting responses in multiple environments

    NARCIS (Netherlands)

    Malosetti Zunin, Marcos; Bustos-Korts, Daniela; Boer, Martin P.; Eeuwijk, van Fred A.

    2016-01-01

    Prediction of the phenotypes for a set of genotypes across multiple environments is a fundamental task in any plant breeding program. Genomic prediction (GP) can assist selection decisions by combining incomplete phenotypic information over multiple environments (MEs) with dense sets of markers.

  11. Solomonoff Prediction and Occam's Razor

    NARCIS (Netherlands)

    Sterkenburg, T.F.

    2016-01-01

    Algorithmic information theory gives an idealized notion of compressibility that is often presented as an objective measure of simplicity. It is suggested at times that Solomonoff prediction, or algorithmic information theory in a predictive setting, can deliver an argument to justify Occam’s razor.

  12. Zephyr - the next generation prediction

    DEFF Research Database (Denmark)

    Giebel, G.; Landberg, L.; Nielsen, Torben Skov

    2001-01-01

    Two of the most successful short-term prediction models (and the only ones in operational use at utilities) are going to be merged into one: the Risø model, developed by Landberg and the Wind Power Prediction Tool WPPT, developed at the Department of Mathematical Modelling IMM of the Danish Techn...

  13. Predictions of nuclear charge radii

    Science.gov (United States)

    Bao, M.; Lu, Y.; Zhao, Y. M.; Arima, A.

    2016-12-01

    The nuclear charge radius is a fundamental property of an atomic nucleus. In this article we study the predictive power of empirical relations for experimental nuclear charge radii of neighboring nuclei and predict the unknown charge radii of 1085 nuclei based on the experimental CR2013 database within an uncertainty of 0.03 fm.

  14. Update on protein structure prediction

    DEFF Research Database (Denmark)

    Hubbard, T; Tramontano, A; Barton, G

    1996-01-01

    Computational tools for protein structure prediction are of great interest to molecular, structural and theoretical biologists due to a rapidly increasing number of protein sequences with no known structure. In October 1995, a workshop was held at IRBM to predict as much as possible about a numbe...

  15. Quadratic prediction of factor scores

    NARCIS (Netherlands)

    Wansbeek, T

    1999-01-01

    Factor scores are naturally predicted by means of their conditional expectation given the indicators y. Under normality this expectation is linear in y but in general it is an unknown function of y. II is discussed that under nonnormality factor scores can be more precisely predicted by a quadratic

  16. Predicting Acoustics in Class Rooms

    DEFF Research Database (Denmark)

    Christensen, Claus Lynge; Rindel, Jens Holger

    2005-01-01

    Typical class rooms have fairly simple geometries, even so room acoustics in this type of room is difficult to predict using today's room acoustic computer modeling software. The reasons why acoustics of class rooms are harder to predict than acoustics of complicated concert halls might...

  17. Predictions for Excited Strange Baryons

    Energy Technology Data Exchange (ETDEWEB)

    Fernando, Ishara P.; Goity, Jose L. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-04-01

    An assessment is made of predictions for excited hyperon masses which follow from flavor symmetry and consistency with a 1/N c expansion of QCD. Such predictions are based on presently established baryonic resonances. Low lying hyperon resonances which do not seem to fit into the proposed scheme are discussed.

  18. Can Satellites Aid Earthquake Predictions?

    Institute of Scientific and Technical Information of China (English)

    John Roach; 李晓辉

    2004-01-01

    @@ Earthquake prediction is an imprecise science, and to illustrate the point,many experts point to the story of Tangshen①, China. On July 28, 1976, a magnitude② 7. 6 earthquake struck the city of Tangshen, China, without warning. None of the signs of the successful prediction from a year and half earlier were present. An estimated 250,000 people died.

  19. Prediction, Regression and Critical Realism

    DEFF Research Database (Denmark)

    Næss, Petter

    2004-01-01

    This paper considers the possibility of prediction in land use planning, and the use of statistical research methods in analyses of relationships between urban form and travel behaviour. Influential writers within the tradition of critical realism reject the possibility of predicting social...... of prediction necessary and possible in spatial planning of urban development. Finally, the political implications of positions within theory of science rejecting the possibility of predictions about social phenomena are addressed....... phenomena. This position is fundamentally problematic to public planning. Without at least some ability to predict the likely consequences of different proposals, the justification for public sector intervention into market mechanisms will be frail. Statistical methods like regression analyses are commonly...

  20. Psychometric prediction of penitentiary recidivism.

    Science.gov (United States)

    Medina García, Pedro M; Baños Rivera, Rosa M

    2016-05-01

    Attempts to predict prison recidivism based on the personality have not been very successful. This study aims to provide data on recidivism prediction based on the scores on a personality questionnaire. For this purpose, a predictive model combining the actuarial procedure with a posteriori probability was developed, consisting of the probabilistic calculation of the effective verification of the event once it has already occurred. Cuestionario de Personalidad Situacional (CPS; Fernández, Seisdedos, & Mielgo, 1998) was applied to 978 male inmates classified as recidivists or non-recidivists. High predictive power was achieved, with the area under the curve (AUC) of 0.85 (p <.001; Se = 0.012; 95% CI [0.826, 0.873]. The answers to the CPS items made it possible to properly discriminate 77.3% of the participants. These data indicate the important role of the personality as a key factor in understanding delinquency and predicting recidivism.

  1. Prediction of molecular crystal structures

    CERN Document Server

    Beyer, T

    2001-01-01

    The ab initio prediction of molecular crystal structures is a scientific challenge. Reliability of first-principle prediction calculations would show a fundamental understanding of crystallisation. Crystal structure prediction is also of considerable practical importance as different crystalline arrangements of the same molecule in the solid state (polymorphs)are likely to have different physical properties. A method of crystal structure prediction based on lattice energy minimisation has been developed in this work. The choice of the intermolecular potential and of the molecular model is crucial for the results of such studies and both of these criteria have been investigated. An empirical atom-atom repulsion-dispersion potential for carboxylic acids has been derived and applied in a crystal structure prediction study of formic, benzoic and the polymorphic system of tetrolic acid. As many experimental crystal structure determinations at different temperatures are available for the polymorphic system of parac...

  2. A Regenerative Prediction Algorithm for Indian Rainfall Prediction

    Directory of Open Access Journals (Sweden)

    SEEMA MAHAJAN

    2013-11-01

    Full Text Available Rainfall forecasting is critical for the crop planning and water management strategies. Proposed study presents a novel approach for modelling time series precipitation data. The 51 years of Indian rainfall data is used for the development of the model. We use nonlinear predictive code based on 11th order with 240 coefficients. Coefficients are optimized using gradient descendent algorithm. Algorithm is tested using 40 years of rainfall training data. Prediction error tested outside training period is found less than1% for few months. Prediction period is extended to one year by including progressive predicted values in input samples using regenerative feedback algorithm. This model is applied for different training and testing periods with average error of 2% to 10%.

  3. Prediction of Competitive Microbial Growth.

    Science.gov (United States)

    Fujikawa, Hiroshi

    2016-01-01

     Prediction of competitive microbial growth is becoming important for microbial food safety. There would be two approaches to predict competitive microbial growth with mathematical models. The first approach is the development of a growth model for competitive microbes. Among several candidates for the competition model considered, the combination of the primary growth model of the new logistic (NL) model and the competition model of the Lotka-Vorttera (LV) model showed the best performance in predicting microbial competitive growth in the mixed culture of two species. This system further successfully predicted the growth of three competitive species in mixed culture. The second approach is the application of the secondary model especially for the parameter of the maximum cell population in the primary growth model. The combination of the NL model and a polynomial model for the maximum population successfully predicted Salmonella growth in raw ground beef. This system further successfully predicted Salmonella growth in beef at various initial concentrations and temperatures. The first approach requires microbial growth data in monoculture for analysis. The second approach to the prediction of competitive growth from the viewpoint of microbial food safety would be more suitable for practical application.

  4. Toolbox for Protein Structure Prediction.

    Science.gov (United States)

    Roche, Daniel Barry; McGuffin, Liam James

    2016-01-01

    Protein tertiary structure prediction algorithms aim to predict, from amino acid sequence, the tertiary structure of a protein. In silico protein structure prediction methods have become extremely important, as in vitro-based structural elucidation is unable to keep pace with the current growth of sequence databases due to high-throughput next-generation sequencing, which has exacerbated the gaps in our knowledge between sequences and structures.Here we briefly discuss protein tertiary structure prediction, the biennial competition for the Critical Assessment of Techniques for Protein Structure Prediction (CASP) and its role in shaping the field. We also discuss, in detail, our cutting-edge web-server method IntFOLD2-TS for tertiary structure prediction. Furthermore, we provide a step-by-step guide on using the IntFOLD2-TS web server, along with some real world examples, where the IntFOLD server can and has been used to improve protein tertiary structure prediction and aid in functional elucidation.

  5. SIFT missense predictions for genomes.

    Science.gov (United States)

    Vaser, Robert; Adusumalli, Swarnaseetha; Leng, Sim Ngak; Sikic, Mile; Ng, Pauline C

    2016-01-01

    The SIFT (sorting intolerant from tolerant) algorithm helps bridge the gap between mutations and phenotypic variations by predicting whether an amino acid substitution is deleterious. SIFT has been used in disease, mutation and genetic studies, and a protocol for its use has been previously published with Nature Protocols. This updated protocol describes SIFT 4G (SIFT for genomes), which is a faster version of SIFT that enables practical computations on reference genomes. Users can get predictions for single-nucleotide variants from their organism of interest using the SIFT 4G annotator with SIFT 4G's precomputed databases. The scope of genomic predictions is expanded, with predictions available for more than 200 organisms. Users can also run the SIFT 4G algorithm themselves. SIFT predictions can be retrieved for 6.7 million variants in 4 min once the database has been downloaded. If precomputed predictions are not available, the SIFT 4G algorithm can compute predictions at a rate of 2.6 s per protein sequence. SIFT 4G is available from http://sift-dna.org/sift4g.

  6. Numerical weather prediction model tuning via ensemble prediction system

    Science.gov (United States)

    Jarvinen, H.; Laine, M.; Ollinaho, P.; Solonen, A.; Haario, H.

    2011-12-01

    This paper discusses a novel approach to tune predictive skill of numerical weather prediction (NWP) models. NWP models contain tunable parameters which appear in parameterizations schemes of sub-grid scale physical processes. Currently, numerical values of these parameters are specified manually. In a recent dual manuscript (QJRMS, revised) we developed a new concept and method for on-line estimation of the NWP model parameters. The EPPES ("Ensemble prediction and parameter estimation system") method requires only minimal changes to the existing operational ensemble prediction infra-structure and it seems very cost-effective because practically no new computations are introduced. The approach provides an algorithmic decision making tool for model parameter optimization in operational NWP. In EPPES, statistical inference about the NWP model tunable parameters is made by (i) generating each member of the ensemble of predictions using different model parameter values, drawn from a proposal distribution, and (ii) feeding-back the relative merits of the parameter values to the proposal distribution, based on evaluation of a suitable likelihood function against verifying observations. In the presentation, the method is first illustrated in low-order numerical tests using a stochastic version of the Lorenz-95 model which effectively emulates the principal features of ensemble prediction systems. The EPPES method correctly detects the unknown and wrongly specified parameters values, and leads to an improved forecast skill. Second, results with an atmospheric general circulation model based ensemble prediction system show that the NWP model tuning capacity of EPPES scales up to realistic models and ensemble prediction systems. Finally, a global top-end NWP model tuning exercise with preliminary results is published.

  7. The Theory of Linear Prediction

    CERN Document Server

    Vaidyanathan, PP

    2007-01-01

    Linear prediction theory has had a profound impact in the field of digital signal processing. Although the theory dates back to the early 1940s, its influence can still be seen in applications today. The theory is based on very elegant mathematics and leads to many beautiful insights into statistical signal processing. Although prediction is only a part of the more general topics of linear estimation, filtering, and smoothing, this book focuses on linear prediction. This has enabled detailed discussion of a number of issues that are normally not found in texts. For example, the theory of vecto

  8. Adaptive filtering prediction and control

    CERN Document Server

    Goodwin, Graham C

    2009-01-01

    Preface1. Introduction to Adaptive TechniquesPart 1. Deterministic Systems2. Models for Deterministic Dynamical Systems3. Parameter Estimation for Deterministic Systems4. Deterministic Adaptive Prediction5. Control of Linear Deterministic Systems6. Adaptive Control of Linear Deterministic SystemsPart 2. Stochastic Systems7. Optimal Filtering and Prediction8. Parameter Estimation for Stochastic Dynamic Systems9. Adaptive Filtering and Prediction10. Control of Stochastic Systems11. Adaptive Control of Stochastic SystemsAppendicesA. A Brief Review of Some Results from Systems TheoryB. A Summary o

  9. Confidence scores for prediction models

    DEFF Research Database (Denmark)

    Gerds, Thomas Alexander; van de Wiel, MA

    2011-01-01

    modelling strategy is applied to different training sets. For each modelling strategy we estimate a confidence score based on the same repeated bootstraps. A new decomposition of the expected Brier score is obtained, as well as the estimates of population average confidence scores. The latter can be used...... to distinguish rival prediction models with similar prediction performances. Furthermore, on the subject level a confidence score may provide useful supplementary information for new patients who want to base a medical decision on predicted risk. The ideas are illustrated and discussed using data from cancer...

  10. Arctic Sea Ice Predictability and the Sea Ice Prediction Network

    Science.gov (United States)

    Wiggins, H. V.; Stroeve, J. C.

    2014-12-01

    Drastic reductions in Arctic sea ice cover have increased the demand for Arctic sea ice predictions by a range of stakeholders, including local communities, resource managers, industry and the public. The science of sea-ice prediction has been challenged to keep up with these developments. Efforts such as the SEARCH Sea Ice Outlook (SIO; http://www.arcus.org/sipn/sea-ice-outlook) and the Sea Ice for Walrus Outlook have provided a forum for the international sea-ice prediction and observing community to explore and compare different approaches. The SIO, originally organized by the Study of Environmental Change (SEARCH), is now managed by the new Sea Ice Prediction Network (SIPN), which is building a collaborative network of scientists and stakeholders to improve arctic sea ice prediction. The SIO synthesizes predictions from a variety of methods, including heuristic and from a statistical and/or dynamical model. In a recent study, SIO data from 2008 to 2013 were analyzed. The analysis revealed that in some years the predictions were very successful, in other years they were not. Years that were anomalous compared to the long-term trend have proven more difficult to predict, regardless of which method was employed. This year, in response to feedback from users and contributors to the SIO, several enhancements have been made to the SIO reports. One is to encourage contributors to provide spatial probability maps of sea ice cover in September and the first day each location becomes ice-free; these are an example of subseasonal to seasonal, local-scale predictions. Another enhancement is a separate analysis of the modeling contributions. In the June 2014 SIO report, 10 of 28 outlooks were produced from models that explicitly simulate sea ice from dynamic-thermodynamic sea ice models. Half of the models included fully-coupled (atmosphere, ice, and ocean) models that additionally employ data assimilation. Both of these subsets (models and coupled models with data

  11. Predicting Success in Elementary Algebra

    Science.gov (United States)

    Mogull, R. G.; Rosengarten, W., Jr.

    1974-01-01

    The purpose of this study was to develop a device for predicting student success in a high school Elementary Algebra course. It was intended to assist guidance counselors in advising students in selecting the most appropriate mathematics course. (Editor)

  12. Time-predictable Stack Caching

    DEFF Research Database (Denmark)

    Abbaspourseyedi, Sahar

    complicated and less imprecise. Time-predictable computer architectures provide solutions to this problem. As accesses to the data in caches are one source of timing unpredictability, devising methods for improving the timepredictability of caches are important. Stack data, with statically analyzable......Embedded systems are computing systems for controlling and interacting with physical environments. Embedded systems with special timing constraints where the system needs to meet deadlines are referred to as real-time systems. In hard real-time systems, missing a deadline causes the system to fail...... addresses, provides an opportunity to predict and tighten the WCET of accesses to data in caches. In this thesis, we introduce the time-predictable stack cache design and implementation within a time-predictable processor. We introduce several optimizations to our design for tightening the WCET while...

  13. Shortcomings in wheat yield predictions

    Science.gov (United States)

    Semenov, Mikhail A.; Mitchell, Rowan A. C.; Whitmore, Andrew P.; Hawkesford, Malcolm J.; Parry, Martin A. J.; Shewry, Peter R.

    2012-06-01

    Predictions of a 40-140% increase in wheat yield by 2050, reported in the UK Climate Change Risk Assessment, are based on a simplistic approach that ignores key factors affecting yields and hence are seriously misleading.

  14. New Tool to Predict Glaucoma

    Science.gov (United States)

    ... News About Us Donate In This Section A New Tool to Predict Glaucoma email Send this article ... determine if a patient has glaucoma. Recently, a new tool has become available to eye care specialists ...

  15. Prediction, Regression and Critical Realism

    DEFF Research Database (Denmark)

    Næss, Petter

    2004-01-01

    This paper considers the possibility of prediction in land use planning, and the use of statistical research methods in analyses of relationships between urban form and travel behaviour. Influential writers within the tradition of critical realism reject the possibility of predicting social...... seen as necessary in order to identify aggregate level effects of policy measures, but are questioned by many advocates of critical realist ontology. Using research into the relationship between urban structure and travel as an example, the paper discusses relevant research methods and the kinds...... of prediction necessary and possible in spatial planning of urban development. Finally, the political implications of positions within theory of science rejecting the possibility of predictions about social phenomena are addressed....

  16. Trading Network Predicts Stock Price

    Science.gov (United States)

    Sun, Xiao-Qian; Shen, Hua-Wei; Cheng, Xue-Qi

    2014-01-01

    Stock price prediction is an important and challenging problem for studying financial markets. Existing studies are mainly based on the time series of stock price or the operation performance of listed company. In this paper, we propose to predict stock price based on investors' trading behavior. For each stock, we characterize the daily trading relationship among its investors using a trading network. We then classify the nodes of trading network into three roles according to their connectivity pattern. Strong Granger causality is found between stock price and trading relationship indices, i.e., the fraction of trading relationship among nodes with different roles. We further predict stock price by incorporating these trading relationship indices into a neural network based on time series of stock price. Experimental results on 51 stocks in two Chinese Stock Exchanges demonstrate the accuracy of stock price prediction is significantly improved by the inclusion of trading relationship indices.

  17. Time series prediction in agroecosystems

    Science.gov (United States)

    Cortina-Januchs, M. G.; Quintanilla-Dominguez, J.; Vega-Corona, A.; Andina, D.

    2012-04-01

    This work proposes a novel model to predict time series such as frost, precipitation, temperature, solar radiation, all of them important variables for the agriculture process. In the proposed model, Artificial Neural Networks (ANN) combined with clustering algorithms and sensor data fusion are used. The real time series are obtained from different sensors. The clustering algorithms find relationships between variables, clustering involves the task of dividing data sets, which assigns the same label to members who belong to the same group, so that each group is homogeneous and distinct from the others. Those relationships provide information to the ANN in order to obtain the time series prediction. The most important issue of ANN in time series prediction is generalization, which refers to their ability to produce reasonable predictions on data sets other than those used for the estimation of the model parameters.

  18. Trading network predicts stock price.

    Science.gov (United States)

    Sun, Xiao-Qian; Shen, Hua-Wei; Cheng, Xue-Qi

    2014-01-16

    Stock price prediction is an important and challenging problem for studying financial markets. Existing studies are mainly based on the time series of stock price or the operation performance of listed company. In this paper, we propose to predict stock price based on investors' trading behavior. For each stock, we characterize the daily trading relationship among its investors using a trading network. We then classify the nodes of trading network into three roles according to their connectivity pattern. Strong Granger causality is found between stock price and trading relationship indices, i.e., the fraction of trading relationship among nodes with different roles. We further predict stock price by incorporating these trading relationship indices into a neural network based on time series of stock price. Experimental results on 51 stocks in two Chinese Stock Exchanges demonstrate the accuracy of stock price prediction is significantly improved by the inclusion of trading relationship indices.

  19. GIPSy: Genomic island prediction software.

    Science.gov (United States)

    Soares, Siomar C; Geyik, Hakan; Ramos, Rommel T J; de Sá, Pablo H C G; Barbosa, Eudes G V; Baumbach, Jan; Figueiredo, Henrique C P; Miyoshi, Anderson; Tauch, Andreas; Silva, Artur; Azevedo, Vasco

    2016-08-20

    Bacteria are highly diverse organisms that are able to adapt to a broad range of environments and hosts due to their high genomic plasticity. Horizontal gene transfer plays a pivotal role in this genome plasticity and in evolution by leaps through the incorporation of large blocks of genome sequences, ordinarily known as genomic islands (GEIs). GEIs may harbor genes encoding virulence, metabolism, antibiotic resistance and symbiosis-related functions, namely pathogenicity islands (PAIs), metabolic islands (MIs), resistance islands (RIs) and symbiotic islands (SIs). Although many software for the prediction of GEIs exist, they only focus on PAI prediction and present other limitations, such as complicated installation and inconvenient user interfaces. Here, we present GIPSy, the genomic island prediction software, a standalone and user-friendly software for the prediction of GEIs, built on our previously developed pathogenicity island prediction software (PIPS). We also present four application cases in which we crosslink data from literature to PAIs, MIs, RIs and SIs predicted by GIPSy. Briefly, GIPSy correctly predicted the following previously described GEIs: 13 PAIs larger than 30kb in Escherichia coli CFT073; 1 MI for Burkholderia pseudomallei K96243, which seems to be a miscellaneous island; 1 RI of Acinetobacter baumannii AYE, named AbaR1; and, 1 SI of Mesorhizobium loti MAFF303099 presenting a mosaic structure. GIPSy is the first life-style-specific genomic island prediction software to perform analyses of PAIs, MIs, RIs and SIs, opening a door for a better understanding of bacterial genome plasticity and the adaptation to new traits.

  20. Prediction of CBS tidal evolution

    Science.gov (United States)

    Dryomova, G. N.

    The time series of basic processes, accompanying the tidal evolution of star components of Close Binary Systems (CBS) are predicted in the framework of evolutionary stellar models by Claret (2004). The series includes the apsidal motion period, timescale of synchronization of axial rotation of a star with the orbital revolution, the orbit circularization timescale, and the age. Data from the catalogues by Svechnikov & Perevozkina (1999) and by Torres, Andersen, Gimenez (2010) are used for testing the sensitivity of the numerical prediction algorithm.

  1. High sensitivity RNA pseudoknot prediction

    OpenAIRE

    Huang, Xiaolu; Ali, Hesham

    2006-01-01

    Most ab initio pseudoknot predicting methods provide very few folding scenarios for a given RNA sequence and have low sensitivities. RNA researchers, in many cases, would rather sacrifice the specificity for a much higher sensitivity for pseudoknot detection. In this study, we introduce the Pseudoknot Local Motif Model and Dynamic Partner Sequence Stacking (PLMM_DPSS) algorithm which predicts all PLM model pseudoknots within an RNA sequence in a neighboring-region-interference-free fashion. T...

  2. Dividend Predictability around the World

    DEFF Research Database (Denmark)

    Rangvid, Jesper; Schmeling, Maik; Schrimpf, Andreas

    in the time-series dimension (time variation in dividend yields strongly predicts future dividend growth rates) and in the cross- country dimension (sorting countries into portfolios depending on their lagged dividend yield produces a spread in dividend growth rates of more than 20% p.a.). In an economic...... assessment of this finding, we show that cash flow predictability is stronger in smaller and medium- sized countries because these countries also have more volatile cash flow growth and higher idiosyncratic return volatility....

  3. Prediction of the Chandler wobble

    Science.gov (United States)

    Zotov, L.; Bizouard, C.

    2015-08-01

    Chandler wobble amplitude have been decreasing in 2010s as in 1930s. We try to predict its future behaviour through prediction of its complex envelope. The excitation of the Chandler wobble (ChW) reconstructed by Panteleev's filter was also analized. The equation for the complex envelope propagation through the Euler-Liouville equation was derived. Similarities with the climate change characteristics are discussed.

  4. Prediction of molecular crystal structures

    Energy Technology Data Exchange (ETDEWEB)

    Beyer, Theresa

    2001-07-01

    The ab initio prediction of molecular crystal structures is a scientific challenge. Reliability of first-principle prediction calculations would show a fundamental understanding of crystallisation. Crystal structure prediction is also of considerable practical importance as different crystalline arrangements of the same molecule in the solid state (polymorphs)are likely to have different physical properties. A method of crystal structure prediction based on lattice energy minimisation has been developed in this work. The choice of the intermolecular potential and of the molecular model is crucial for the results of such studies and both of these criteria have been investigated. An empirical atom-atom repulsion-dispersion potential for carboxylic acids has been derived and applied in a crystal structure prediction study of formic, benzoic and the polymorphic system of tetrolic acid. As many experimental crystal structure determinations at different temperatures are available for the polymorphic system of paracetamol (acetaminophen), the influence of the variations of the molecular model on the crystal structure lattice energy minima, has also been studied. The general problem of prediction methods based on the assumption that the experimental thermodynamically stable polymorph corresponds to the global lattice energy minimum, is that more hypothetical low lattice energy structures are found within a few kJ mol{sup -1} of the global minimum than are likely to be experimentally observed polymorphs. This is illustrated by the results for molecule I, 3-oxabicyclo(3.2.0)hepta-1,4-diene, studied for the first international blindtest for small organic crystal structures organised by the Cambridge Crystallographic Data Centre (CCDC) in May 1999. To reduce the number of predicted polymorphs, additional factors to thermodynamic criteria have to be considered. Therefore the elastic constants and vapour growth morphologies have been calculated for the lowest lattice energy

  5. Predictive Characteristics of Malignant Pheochromocytoma

    OpenAIRE

    Park, Junsoo; Song, Cheryn; Park, Myungchan; Yoo, Sangjun; Park, Se Jun; Hong, SeokJun; Hong, Bumsik; Kim, Choung-Soo; Ahn, Hanjong

    2011-01-01

    Purpose The prognosis of patients with malignant pheochromocytoma is poor, but the predictive factors are not well understood. We aimed to identify the clinical characteristics predictive of malignancy after initial surgical removal in patients with pheochromocytoma. Materials and Methods We retrospectively reviewed the records of 152 patients diagnosed with pheochromocytoma, including 5 (3.3%) with metastasis at the time of the initial surgical excision and 12 (7.9%) who developed metastasis...

  6. Global Predictability and Prediction Skill of Atmospheric Rivers

    Science.gov (United States)

    Deflorio, M. J.

    2016-12-01

    Atmospheric rivers (ARs) are responsible for the majority of horizontal water vapor transport in the midlatitudes and can intensify downstream precipitation and influence flooding, snowpack and water availability. Consequently, there is significant incentive to estimate the predictability and quantify our prediction skill of AR events in operational forecast models, especially weeks to months in advance. Understanding and exploiting the full extent of AR predictability is vital for watershed and hazard preparation and water resource management in areas that are sensitive to heavy precipitation events often associated with ARs. Though the predictability limits and prediction skill of AR-related quantities such as precipitation and integrated vapor transport have recently been quantified for very limited regional areas, a systematic assessment of AR events themselves (with explicit consideration of AR geometries/intensities) using contemporary operational forecast models on a global scale has not yet been made. In this study, we create new objective skill metrics for AR events and quantify predictability limits and prediction skill of ARs in two decades of AR hindcasts from several operational models at lead times ranging from 1 day to 1 month. Our methodology is performed globally, but also allows for regional investigation of observed AR events of interest. We also examine the sensitivity of these skill estimates to large scale modes of climate variability (e.g. the El Niño-Southern Oscillation) in an effort to leverage higher skill conditioned upon particular phases of these modes. This study contributes to the overarching goals of the international WMO Subseasonal to Seasonal Project by utilizing operational forecast and hindcast experiments with an emphasis on subseasonal forecasting applications.

  7. Seasonal Drought Prediction in India

    Science.gov (United States)

    Shah, R.; Mishra, V.

    2015-12-01

    Drought is among the most costly natural disasters in India. Seasonal prediction of drought can assist planners to manage agriculture and water resources. Such information can be valuable for a country like India where 60% of agriculture is rain-fed. Here we evaluate precipitation and temperature forecast from the NCEP's CFSV2 for seasonal drought prediction in India. We demonstrate the utility of the seasonal prediction of precipitation and temperature for drought forecast at 1-2 months lead time at a high spatial resolution. Precipitation from CFSv2 showed moderate correlations with observed up to two months lead. For one month lead, we found a significant correlation between CFSv2 and observed precipitation during winter season. Air temperature from the CFSv2 showed a good correlation with observed temperature during the winter. We forced the Variable Infiltration Capacity (VIC) model with the CFSv2 forecast of precipitation and air temperature to generate forecast of hydrologic variables such as soil moisture and total runoff. We find that errors of the prediction reduce for the two month lead time in the majority of the study domain except the northern India. Skills of Initial Hydrologic Conditions combined with moderate skills of forcings based on the CFSv2 showed ability of drought prediction in India. The developed system was able to successfully predict observed top layer soil moisture and observed drought based on satellite remote sensing in India.

  8. Strategy and methodology of dynamical analogue prediction

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In order to effectively improve numerical prediction level by using current models and data, the strategy and methodology of dynamical analogue prediction (DAP) is deeply studied in the present paper. A new idea to predict the prediction errors of dynamical model on the basis of historical analogue information is put forward so as to transform the dynamical prediction problem into the estimation problem of prediction errors. In terms of such an idea, a new prediction method of final analogue correction of errors (FACE) is developed. Furthermore, the FACE is applied to extra-seasonal prediction experiments on an operational atmosphere-ocean coupled general circulation model. Prediction results of summer mean circulation and total precipitation show that the FACE can to some extent reduce prediction errors, recover prediction variances, and improve prediction skills. Besides, sensitive experiments also show that predictions based on the FACE are evidently influenced by the number of analogues, analogue-selected variables and analogy metric.

  9. Neural Elements for Predictive Coding

    Directory of Open Access Journals (Sweden)

    Stewart SHIPP

    2016-11-01

    Full Text Available Predictive coding theories of sensory brain function interpret the hierarchical construction of the cerebral cortex as a Bayesian, generative model capable of predicting the sensory data consistent with any given percept. Predictions are fed backwards in the hierarchy and reciprocated by prediction error in the forward direction, acting to modify the representation of the outside world at increasing levels of abstraction, and so to optimize the nature of perception over a series of iterations. This accounts for many ‘illusory’ instances of perception where what is seen (heard, etc is unduly influenced by what is expected, based on past experience. This simple conception, the hierarchical exchange of prediction and prediction error, confronts a rich cortical microcircuitry that is yet to be fully documented. This article presents the view that, in the current state of theory and practice, it is profitable to begin a two-way exchange: that predictive coding theory can support an understanding of cortical microcircuit function, and prompt particular aspects of future investigation, whilst existing knowledge of microcircuitry can, in return, influence theoretical development. As an example, a neural inference arising from the earliest formulations of predictive coding is that the source populations of forwards and backwards pathways should be completely separate, given their functional distinction; this aspect of circuitry – that neurons with extrinsically bifurcating axons do not project in both directions – has only recently been confirmed. Here, the computational architecture prescribed by a generalized (free-energy formulation of predictive coding is combined with the classic ‘canonical microcircuit’ and the laminar architecture of hierarchical extrinsic connectivity to produce a template schematic, that is further examined in the light of (a updates in the microcircuitry of primate visual cortex, and (b rapid technical advances made

  10. Predictive mechanisms in idiom comprehension.

    Science.gov (United States)

    Vespignani, Francesco; Canal, Paolo; Molinaro, Nicola; Fonda, Sergio; Cacciari, Cristina

    2010-08-01

    Prediction is pervasive in human cognition and plays a central role in language comprehension. At an electrophysiological level, this cognitive function contributes substantially in determining the amplitude of the N400. In fact, the amplitude of the N400 to words within a sentence has been shown to depend on how predictable those words are: The more predictable a word, the smaller the N400 elicited. However, predictive processing can be based on different sources of information that allow anticipation of upcoming constituents and integration in context. In this study, we investigated the ERPs elicited during the comprehension of idioms, that is, prefabricated multiword strings stored in semantic memory. When a reader recognizes a string of words as an idiom before the idiom ends, she or he can develop expectations concerning the incoming idiomatic constituents. We hypothesized that the expectations driven by the activation of an idiom might differ from those driven by discourse-based constraints. To this aim, we compared the ERP waveforms elicited by idioms and two literal control conditions. The results showed that, in both cases, the literal conditions exhibited a more negative potential than the idiomatic condition. Our analyses suggest that before idiom recognition the effect is due to modulation of the N400 amplitude, whereas after idiom recognition a P300 for the idiomatic sentence has a fundamental role in the composition of the effect. These results suggest that two distinct predictive mechanisms are at work during language comprehension, based respectively on probabilistic information and on categorical template matching.

  11. Link Prediction via Matrix Completion

    CERN Document Server

    Pech, Ratha; Pan, Liming; Cheng, Hong; Zhou, Tao

    2016-01-01

    Inspired by practical importance of social networks, economic networks, biological networks and so on, studies on large and complex networks have attracted a surge of attentions in the recent years. Link prediction is a fundamental issue to understand the mechanisms by which new links are added to the networks. We introduce the method of robust principal component analysis (robust PCA) into link prediction, and estimate the missing entries of the adjacency matrix. On one hand, our algorithm is based on the sparsity and low rank property of the matrix, on the other hand, it also performs very well when the network is dense. This is because a relatively dense real network is also sparse in comparison to the complete graph. According to extensive experiments on real networks from disparate fields, when the target network is connected and sufficiently dense, whatever it is weighted or unweighted, our method is demonstrated to be very effective and with prediction accuracy being considerably improved comparing wit...

  12. Human motion simulation predictive dynamics

    CERN Document Server

    Abdel-Malek, Karim

    2013-01-01

    Simulate realistic human motion in a virtual world with an optimization-based approach to motion prediction. With this approach, motion is governed by human performance measures, such as speed and energy, which act as objective functions to be optimized. Constraints on joint torques and angles are imposed quite easily. Predicting motion in this way allows one to use avatars to study how and why humans move the way they do, given specific scenarios. It also enables avatars to react to infinitely many scenarios with substantial autonomy. With this approach it is possible to predict dynamic motion without having to integrate equations of motion -- rather than solving equations of motion, this approach solves for a continuous time-dependent curve characterizing joint variables (also called joint profiles) for every degree of freedom. Introduces rigorous mathematical methods for digital human modelling and simulation Focuses on understanding and representing spatial relationships (3D) of biomechanics Develops an i...

  13. Predictability of Mobile Phone Associations

    DEFF Research Database (Denmark)

    Jensen, Bjørn Sand; Larsen, Jan; Hansen, Lars Kai

    2010-01-01

    Prediction and understanding of human behavior is of high importance in many modern applications and research areas ranging from context-aware services, wireless resource allocation to social sciences. In this study we collect a novel dataset using standard mobile phones and analyze how...... representation, and general behavior. This is of vital interest in the development of context-aware services which rely on forecasting based on mobile phone sensors....... the predictability of mobile sensors, acting as proxies for humans, change with time scale and sensor type such as GSM and WLAN. Applying recent information theoretic methods, it is demonstrated that an upper bound on predictability is relatively high for all sensors given the complete history (typically above 90...

  14. Algorithms for Protein Structure Prediction

    DEFF Research Database (Denmark)

    Paluszewski, Martin

    The problem of predicting the three-dimensional structure of a protein given its amino acid sequence is one of the most important open problems in bioinformatics. One of the carbon atoms in amino acids is the C-atom and the overall structure of a protein is often represented by a so-called C...... is competitive in quality and speed with other state-of-the-art decoy generation algorithms. Our third C-trace reconstruction approach is based on bee-colony optimization [24]. We demonstrate why this algorithm has some important properties that makes it suitable for protein structure prediction. Our approach......-trace. Here we present three different approaches for reconstruction of C-traces from predictable measures. In our first approach [63, 62], the C-trace is positioned on a lattice and a tabu-search algorithm is applied to find minimum energy structures. The energy function is based on half-sphere-exposure (HSE...

  15. High sensitivity RNA pseudoknot prediction.

    Science.gov (United States)

    Huang, Xiaolu; Ali, Hesham

    2007-01-01

    Most ab initio pseudoknot predicting methods provide very few folding scenarios for a given RNA sequence and have low sensitivities. RNA researchers, in many cases, would rather sacrifice the specificity for a much higher sensitivity for pseudoknot detection. In this study, we introduce the Pseudoknot Local Motif Model and Dynamic Partner Sequence Stacking (PLMM_DPSS) algorithm which predicts all PLM model pseudoknots within an RNA sequence in a neighboring-region-interference-free fashion. The PLM model is derived from the existing Pseudobase entries. The innovative DPSS approach calculates the optimally lowest stacking energy between two partner sequences. Combined with the Mfold, PLMM_DPSS can also be used in predicting complicated pseudoknots. The test results of PLMM_DPSS, PKNOTS, iterated loop matching, pknotsRG and HotKnots with Pseudobase sequences have shown that PLMM_DPSS is the most sensitive among the five methods. PLMM_DPSS also provides manageable pseudoknot folding scenarios for further structure determination.

  16. Intelligent Prediction of Ship Maneuvering

    Directory of Open Access Journals (Sweden)

    Miroslaw Lacki

    2016-09-01

    Full Text Available In this paper the author presents an idea of the intelligent ship maneuvering prediction system with the usage of neuroevolution. This may be also be seen as the ship handling system that simulates a learning process of an autonomous control unit, created with artificial neural network. The control unit observes input signals and calculates the values of required parameters of the vessel maneuvering in confined waters. In neuroevolution such units are treated as individuals in population of artificial neural networks, which through environmental sensing and evolutionary algorithms learn to perform given task efficiently. The main task of the system is to learn continuously and predict the values of a navigational parameters of the vessel after certain amount of time, regarding an influence of its environment. The result of a prediction may occur as a warning to navigator to aware him about incoming threat.

  17. Sentence-Level Attachment Prediction

    Science.gov (United States)

    Albakour, M.-Dyaa; Kruschwitz, Udo; Lucas, Simon

    Attachment prediction is the task of automatically identifying email messages that should contain an attachment. This can be useful to tackle the problem of sending out emails but forgetting to include the relevant attachment (something that happens all too often). A common Information Retrieval (IR) approach in analyzing documents such as emails is to treat the entire document as a bag of words. Here we propose a finer-grained analysis to address the problem. We aim at identifying individual sentences within an email that refer to an attachment. If we detect any such sentence, we predict that the email should have an attachment. Using part of the Enron corpus for evaluation we find that our finer-grained approach outperforms previously reported document-level attachment prediction in similar evaluation settings.

  18. Zephyr - the next generation prediction

    DEFF Research Database (Denmark)

    Giebel, G.; Landberg, L.; Nielsen, Torben Skov

    2001-01-01

    Two of the most successful short-term prediction models (and the only ones in operational use at utilities) are going to be merged into one: the Risø model, developed by Landberg and the Wind Power Prediction Tool WPPT, developed at the Department of Mathematical Modelling IMM of the Danish...... Technical University. This paper will describe a new project funded by the Danish Ministry of Energy where the largest Danish utilities (Elkraft, Elsam, Eltra and SEAS) are participating. Two advantages can be achieved by combining the effort: The software architecture will be state-of-the-art, using...... the Java2TM platform and Enterprise Java Beans technology, and it will ensure that the best forecasts are given on all prediction horizons from the short range (0-9 hours) to the long range (36-48 hours). This is because the IMM approach uses online data and advanced statistical methods, which...

  19. Algorithms for Drug Sensitivity Prediction

    Directory of Open Access Journals (Sweden)

    Carlos De Niz

    2016-11-01

    Full Text Available Precision medicine entails the design of therapies that are matched for each individual patient. Thus, predictive modeling of drug responses for specific patients constitutes a significant challenge for personalized therapy. In this article, we consider a review of approaches that have been proposed to tackle the drug sensitivity prediction problem especially with respect to personalized cancer therapy. We first discuss modeling approaches that are based on genomic characterizations alone and further the discussion by including modeling techniques that integrate both genomic and functional information. A comparative analysis of the prediction performance of four representative algorithms, elastic net, random forest, kernelized Bayesian multi-task learning and deep learning, reflecting the broad classes of regularized linear, ensemble, kernelized and neural network-based models, respectively, has been included in the paper. The review also considers the challenges that need to be addressed for successful implementation of the algorithms in clinical practice.

  20. Prediction models in complex terrain

    DEFF Research Database (Denmark)

    Marti, I.; Nielsen, Torben Skov; Madsen, Henrik

    2001-01-01

    are calculated using on-line measurements of power production as well as HIRLAM predictions as input thus taking advantage of the auto-correlation, which is present in the power production for shorter pediction horizons. Statistical models are used to discribe the relationship between observed energy production......The objective of the work is to investigatethe performance of HIRLAM in complex terrain when used as input to energy production forecasting models, and to develop a statistical model to adapt HIRLAM prediction to the wind farm. The features of the terrain, specially the topography, influence...... and HIRLAM predictions. The statistical models belong to the class of conditional parametric models. The models are estimated using local polynomial regression, but the estimation method is here extended to be adaptive in order to allow for slow changes in the system e.g. caused by the annual variations...

  1. Evoked emotions predict food choice.

    Science.gov (United States)

    Dalenberg, Jelle R; Gutjar, Swetlana; Ter Horst, Gert J; de Graaf, Kees; Renken, Remco J; Jager, Gerry

    2014-01-01

    In the current study we show that non-verbal food-evoked emotion scores significantly improve food choice prediction over merely liking scores. Previous research has shown that liking measures correlate with choice. However, liking is no strong predictor for food choice in real life environments. Therefore, the focus within recent studies shifted towards using emotion-profiling methods that successfully can discriminate between products that are equally liked. However, it is unclear how well scores from emotion-profiling methods predict actual food choice and/or consumption. To test this, we proposed to decompose emotion scores into valence and arousal scores using Principal Component Analysis (PCA) and apply Multinomial Logit Models (MLM) to estimate food choice using liking, valence, and arousal as possible predictors. For this analysis, we used an existing data set comprised of liking and food-evoked emotions scores from 123 participants, who rated 7 unlabeled breakfast drinks. Liking scores were measured using a 100-mm visual analogue scale, while food-evoked emotions were measured using 2 existing emotion-profiling methods: a verbal and a non-verbal method (EsSense Profile and PrEmo, respectively). After 7 days, participants were asked to choose 1 breakfast drink from the experiment to consume during breakfast in a simulated restaurant environment. Cross validation showed that we were able to correctly predict individualized food choice (1 out of 7 products) for over 50% of the participants. This number increased to nearly 80% when looking at the top 2 candidates. Model comparisons showed that evoked emotions better predict food choice than perceived liking alone. However, the strongest predictive strength was achieved by the combination of evoked emotions and liking. Furthermore we showed that non-verbal food-evoked emotion scores more accurately predict food choice than verbal food-evoked emotions scores.

  2. Evoked emotions predict food choice.

    Directory of Open Access Journals (Sweden)

    Jelle R Dalenberg

    Full Text Available In the current study we show that non-verbal food-evoked emotion scores significantly improve food choice prediction over merely liking scores. Previous research has shown that liking measures correlate with choice. However, liking is no strong predictor for food choice in real life environments. Therefore, the focus within recent studies shifted towards using emotion-profiling methods that successfully can discriminate between products that are equally liked. However, it is unclear how well scores from emotion-profiling methods predict actual food choice and/or consumption. To test this, we proposed to decompose emotion scores into valence and arousal scores using Principal Component Analysis (PCA and apply Multinomial Logit Models (MLM to estimate food choice using liking, valence, and arousal as possible predictors. For this analysis, we used an existing data set comprised of liking and food-evoked emotions scores from 123 participants, who rated 7 unlabeled breakfast drinks. Liking scores were measured using a 100-mm visual analogue scale, while food-evoked emotions were measured using 2 existing emotion-profiling methods: a verbal and a non-verbal method (EsSense Profile and PrEmo, respectively. After 7 days, participants were asked to choose 1 breakfast drink from the experiment to consume during breakfast in a simulated restaurant environment. Cross validation showed that we were able to correctly predict individualized food choice (1 out of 7 products for over 50% of the participants. This number increased to nearly 80% when looking at the top 2 candidates. Model comparisons showed that evoked emotions better predict food choice than perceived liking alone. However, the strongest predictive strength was achieved by the combination of evoked emotions and liking. Furthermore we showed that non-verbal food-evoked emotion scores more accurately predict food choice than verbal food-evoked emotions scores.

  3. Prediction of eyespot infection risks

    Directory of Open Access Journals (Sweden)

    M. Váòová

    2012-12-01

    Full Text Available The objective of the study was to design a prediction model for eyespot (Tapesia yallundae infection based on climatic factors (temperature, precipitation, air humidity. Data from experiment years 1994-2002 were used to study correlations between the eyespot infection index and individual weather characteristics. The model of prediction was constructed using multiple regression when a separate parameter is assigned to each factor, i.e. the frequency of days with optimum temperatures, humidity, and precipitation. The correlation between relative air humidity and precipitation and the infection index is significant.

  4. Wind energy prediction; Prediccion eolica

    Energy Technology Data Exchange (ETDEWEB)

    Xiberta, B. J.; Florez, M. V. E.

    2004-07-01

    On March 12th, 2004 the Spanish Government modified the legal situation of the renewable energies following the approval of RD 436/2004. This makes necessary the development of wind energy prediction models for its entrance to the daily electricity market like the conventional energies. The improvement of physical models, meteorological models, or a combination of both, is necessary for the prediction of the wind generation. This will guarantee the wind energy full utilization and the participation in the electrical market, as well as the remuneration of the complementary services and the regulation of reactive electricity. In this way wind energy turns into a perfectly manageable one. (Author)

  5. Methods for Predicting Stock Indexes

    Directory of Open Access Journals (Sweden)

    Martha Cecilia García

    2013-11-01

    Full Text Available This paper presents a literature review on methods that have been used in the last two decades to predict Stock Market Indexes. Methods studied range from those enabling to grab the linear characteristics present in the stock market indexes, going through those that focus on non-linear features and finally hybrid methods that are more robust, since they capture linear and non-linear features. In addition, this research includes methods that use macroeconomic variables to predict indexes from different stock exchanges around the world.

  6. Predicting Acoustics in Class Rooms

    DEFF Research Database (Denmark)

    Christensen, Claus Lynge; Rindel, Jens Holger

    2005-01-01

    Typical class rooms have fairly simple geometries, even so room acoustics in this type of room is difficult to predict using today's room acoustic computer modeling software. The reasons why acoustics of class rooms are harder to predict than acoustics of complicated concert halls might...... coefficients that are used in order to describe surface scattering (roughness of material) as well as scattering of reflected sound caused by limited surface size (diffraction). A method which combines scattering caused by diffraction due to surface dimensions, angle of incidence and incident path length...

  7. Predictive models of forest dynamics.

    Science.gov (United States)

    Purves, Drew; Pacala, Stephen

    2008-06-13

    Dynamic global vegetation models (DGVMs) have shown that forest dynamics could dramatically alter the response of the global climate system to increased atmospheric carbon dioxide over the next century. But there is little agreement between different DGVMs, making forest dynamics one of the greatest sources of uncertainty in predicting future climate. DGVM predictions could be strengthened by integrating the ecological realities of biodiversity and height-structured competition for light, facilitated by recent advances in the mathematics of forest modeling, ecological understanding of diverse forest communities, and the availability of forest inventory data.

  8. Prediction of dental caries activity

    OpenAIRE

    Crossner, Claes-Göran

    1980-01-01

    The aim of the present thesis was to find a test for prediction of caries activity which would be useful in routine clinical work.Correlations between oral health, general health, food habits and socioeconomic conditions were investigated in 4- and 8-year-old children. It was found that the salivary secretion rate and the prevalence of oral lactobacilli were factors which might be useful in caries prediction.In 5- and 8-year-old children negative correlations between caries frequency and secr...

  9. Dinosaur fossils predict body temperatures.

    Directory of Open Access Journals (Sweden)

    James F Gillooly

    2006-07-01

    Full Text Available Perhaps the greatest mystery surrounding dinosaurs concerns whether they were endotherms, ectotherms, or some unique intermediate form. Here we present a model that yields estimates of dinosaur body temperature based on ontogenetic growth trajectories obtained from fossil bones. The model predicts that dinosaur body temperatures increased with body mass from approximately 25 degrees C at 12 kg to approximately 41 degrees C at 13,000 kg. The model also successfully predicts observed increases in body temperature with body mass for extant crocodiles. These results provide direct evidence that dinosaurs were reptiles that exhibited inertial homeothermy.

  10. Information criteria for multistep ahead predictions

    OpenAIRE

    Yano, Keisuke; Komaki, Fumiyasu

    2015-01-01

    We propose an information criterion for multistep ahead predictions. It is also used for extrapolations. For the derivation, we consider multistep ahead predictions under local misspecification. In the prediction, we show that Bayesian predictive distributions asymptotically have smaller Kullback--Leibler risks than plug-in predictive distributions. From the results, we construct an information criterion for multistep ahead predictions by using an asymptotically unbiased estimator of the Kull...

  11. CERAPP: Collaborative Estrogen Receptor Activity Prediction Project

    Data.gov (United States)

    U.S. Environmental Protection Agency — Data from a large-scale modeling project called CERAPP (Collaborative Estrogen Receptor Activity Prediction Project) demonstrating using predictive computational...

  12. Hysteresis and the transition between axisymmetric flow and wave flow in the baroclinic annulus

    Science.gov (United States)

    Miller, Timothy L.; Butler, Karen A.

    1991-01-01

    A numerical model is employed to establish the transitions between axisymmetric flow and wave flow in the rotating, differentially heated annulus experiments of Fein for both rigid lid and free surface cases. It is shown that, for most of the transitions, the method of computing a steady axisymmetric flow and then testing its linear stability to wave disturbance results in good agreement with the experiments. Implications for the investigation of the dynamics of the earth's atmosphere are considered.

  13. Long-time Behavior of a Two-layer Model of Baroclinic Quasi-geostrophic Turbulence

    CERN Document Server

    Farhat, Aseel; Titi, Edriss S; Ziane, Mohammed

    2012-01-01

    We study a viscous two-layer quasi-geostrophic beta-plane model that is forced by imposition of a spatially uniform vertical shear in the eastward (zonal) component of the layer flows, or equivalently a spatially uniform north-south temperature gradient. We prove that the model is linearly unstable, but that non-linear solutions are bounded in time by a bound which is independent of the initial data and is determined only by the physical parameters of the model. We further prove, using arguments first presented in the study of the Kuramoto-Sivashinsky equation, the existence of an absorbing ball in appropriate function spaces, and in fact the existence of a compact finite-dimensional attractor, and provide upper bounds for the fractal and Hausdorff dimensions of the attractor. Finally, we show the existence of an inertial manifold for the dynamical system generated by the model's solution operator. Our results provide rigorous justification for observations made by Panetta based on long-time numerical integra...

  14. A note on the deflection of a baroclinic current by a continental shelf

    Science.gov (United States)

    Hsueh, Y.; Zhong, Liejun

    2003-05-01

    The deflection, at a step-shelf fronted coast, of a constant potential vorticity current in a reduced-gravity, inviscid model ocean is studied theoretically. The step shelf, with a depth smaller than the reservoir depth, forces the uplifting of the approaching current and causes water column foreshortening, leading to relative vorticity generation that enhances current deflection to the right (facing the coast). As a consequence, in comparison to the case of a vertical wall coast, the proportion of the transport to the right is increased. For normal incidence for a shelf-depth/reservoir-depth ratio of 0.3 and shelf width to deformation radius ratio of 1.5, more than 90% of the approaching current transport goes to the right and less than 10% to the left. In addition, the (barotropic) dynamic pressure at the coast is low to the right and high to the left (with the highest pressure at the stagnation point). In the vertical wall case, the wall pressures on the flank are equal. For oblique incidence from the left, the deflection to the left is drastically reduced. In fact, there is practically no steady-state flow diverted to the left (less than 2%) when the approach angle is greater than 60° to the left of normal. In the vertical wall case, the same angle would have to be 90° for the flow to the left to vanish, namely only when the approach current is parallel to the coast to the right.

  15. Formation of columnar baroclinic vortices in thermally stratified nonlinear spin-up

    NARCIS (Netherlands)

    Pacheco, J.R.; Verzicco, R.

    2012-01-01

    We investigate the mechanisms that affect the formation of columnar vortices for spin-up in a cylinder where the temperatures at the horizontal walls are prescribed. Numerical results from the three-dimensional Navier–Stokes equations show that a short-lived instability, suppressed by the combined e

  16. Effects of surface drag on upper-level frontogenesis within a developing baroclinic wave

    Science.gov (United States)

    Zhang, Yi; Tan, Zhemin; Chu, Kekuan

    2016-08-01

    This paper investigates the effects of surface drag on upper-level front with a three-dimensional nonhydrostatic mesoscale numerical model (MM5). To this end, a new and simple potential vorticity intrusion (PVI) index is proposed to quantitatively describe the extent and path that surface drag affects upper-level front. From a PV perspective, the formation of the upper-level front is illustrated as the tropopause folding happens from the stratosphere. The PVI index shows a good correlation with the minimum surface pressure, and tends to increase with the deepening of the surface cyclone and upper-level front. The surface drag acts to damp and delay the development of upper-level front, which could reduce the growth rate of the PVI index. However, the damping presents different effects in different development stages. It is the most significant during the rapid development stage of the surface cyclone. Compared with no surface drag cases, the tropopause is less inclined to intrude into the troposphere due to the surface drag. Positive feedback between the surface cyclone and upper-level front could accelerate the development of the frontal system.

  17. Evidence of Multimodal Structure of the Baroclinic Tide in the Strait of Gibraltar

    Science.gov (United States)

    2006-09-08

    Data ’Departamento de Fisica Aplicada, Facultad de Ciencias del Mar y [6] The experimental data used in this paper were col- Ambientales , Universidad de...de Ciencias del Mar y Ambientales , Universidad de the Norwegian-Greenland Sea, Deep Sea Res., 26, 1199-1223. C~idiz, E-11510 Puerto Real, Spain

  18. Baroclinic internal wave energy distribution in the Baltic Sea derived from 45 years of circulation simulations

    Science.gov (United States)

    Rybin, Artem; Soomere, Tarmo; Kurkina, Oxana; Kurkin, Andrey; Rouvinskaya, Ekaterina; Markus Meier, H. E.

    2016-04-01

    Internal waves and internal tides are an essential component of the functioning of stratified shelf seas. They carry substantial amounts of energy through the water masses, drive key hydrophysical processes such as mixing and overturning and support the functioning of marine ecosystem in many ways. Their particular impact becomes evident near and at the bottom where they often create substantial loads to engineering structures and exert a wide range of impacts on the bottom sediments and evolution of the seabed. We analyse several properties of spatio-temporal distributions of energy of relatively long-period large-scale internal wave motions in the Baltic Sea. The analysis is based on numerically simulated pycnocline variations that are extracted from the hydrographic data calculated by the Rossby Centre Ocean circulation model (RCO) for the entire Baltic Sea for 1961-2005. This model has a horizontal resolution of 2 nautical miles and uses 41 vertical layers with a thickness between 3 m close to the surface and 12 m in 250 m depth. The model is forced with atmospheric data derived from the ERA-40 re-analysis using a regional atmosphere model with a horizontal resolution of 25 km. It also accounts for river inflow and water exchange through the Danish Straits. See (Meier, H.E.M., Höglund, A., 2013. Studying the Baltic Sea circulation with Eulerian tracers, in Soomere, T., Quak, E., eds., Preventive Methods for Coastal Protection, Springer, Cham, Heidelberg, 101-130) for a detailed description of the model and its forcing. The resolution of the model output used in this study (once in 6 hours) is sufficient for estimates of spectral amplitudes of the displacements of isopycnal surfaces with a typical period of 2-12 days. We provide the analysis of kinetic and potential energy of motions with these periods. The resulting maps of the maxima of energy and spatial distributions of near-bottom velocities have been evaluated for the entire simulation interval of 45 years and for single 5-yr intervals. The maxima of energy of such motions are concentrated in an approximately 50 km wide domain along the nearshore of Latvia and the Western Estonian archipelago. Several narrower regions of relatively high concentrations of energy are located around the southern tip of Sweden, along the coasts of Poland and the island of Gotland, and at the northern and north-eastern coasts of the Sea of Bothnia. The performed analysis sheds new light on the potential impact areas of long-period internal wave motions in the Baltic Sea and associated regions of intense mixing and large wave-driven near-bottom velocities.

  19. Nonhydrostatic effects in numerical modeling of mesoscale convective systems and baroclinic waves

    Science.gov (United States)

    Cohen, Charles

    1993-01-01

    The present investigation is concerned with the role of convection upon mesoscale modeling results, particularly when the grid resolution becomes small enough that there is not a clear scale separation between the explicitly resolved circulations and the parameterized clouds. In those situations, the vertical accelerations in explicitly resolved circulations become strong enough that the hydrostatic assumption may no longer be valid. These concerns arise from interests in improving mesoscale modeling per se and in improving the subgrid-scale parameterizations in global models. The hydrostatic and the nonhydrostatic options of the Colorado State University Regional Atmospheric Modeling System were used to simulate dry gravity currents in two dimensions, using several different horizontal grid sizes. With horizontal grid intervals of 10 km or less, nonhydrostatic simulations produce wider and colder heads and weaker but wider forced updrafts than do the hydrostatic simulations. Comparing the hydrostatic and nonhydrostatic models show that the difference between the vertical mass fluxes is much less than the difference between the vertical velocities. When the grid is fine enough to resolve the head of the gravity current, horizontal convergence at the gust front extends upwards almost to the head of the cold air. Vertical mass flux in the forced updraft at the front varies with horizontal grid size mainly as a function of the height of the simulated head. For coarser grids, which do not resolve the head, vertical mass flux at all heights decreases with increasing horizontal grid size. A comparison on nonhydrostatic simulations with horizontal grid intervals of 1 km and 2 km illustrates how decreasing the grid size does not necessarily increase the intensity of the resolved circulation. The smaller grid enables the simulated gravity current to entrain a bubble of warm air behind the head, which results in a weaker circulation with a shorter head and weaker updraft.

  20. Simulation of barotropic and baroclinic tides in the South China Sea

    Institute of Scientific and Technical Information of China (English)

    WU Ziku; LU Xianqing; TIAN Jiwei

    2005-01-01

    The four leading tidal constituents M2, S2, K1 and O1 in the South China Sea are simulated by using POM. The model is forced with tide-generating potential and four leading tidal constituents at the open boundary. In order to simulate more exactly, TOPEX/Poseidon altimeter data are assimilated into the model and the open boundary is optimized. The computed co-tidal charts for M2 and K1 constituents are generally consistent with previous results in this region. The numerical simulation shows that energetic internal tides are generated over the bottom topography such as the Dongsha Islands, the Xisha Islands, the Zhongsha Islands, the Nansha Islands and the Luzon Strait.

  1. Focus on astronomical predictable events

    DEFF Research Database (Denmark)

    Jacobsen, Aase Roland

    2006-01-01

    At the Steno Museum Planetarium we have for many occasions used a countdown clock to get focus om astronomical events. A countdown clock can provide actuality to predictable events, for example The Venus Transit, Opportunity landing on Mars and The Solar Eclipse. The movement of the clock attracs...

  2. Evoked Emotions Predict Food Choice

    NARCIS (Netherlands)

    Dalenberg, Jelle R.; Gutjar, Swetlana; ter Horst, Gert J.; de Graaf, Kees; Renken, Remco J.; Jager, Gerry

    2014-01-01

    In the current study we show that non-verbal food-evoked emotion scores significantly improve food choice prediction over merely liking scores. Previous research has shown that liking measures correlate with choice. However, liking is no strong predictor for food choice in real life environments.

  3. Bankruptcy Prediction with Rough Sets

    NARCIS (Netherlands)

    J.C. Bioch (Cor); V. Popova (Viara)

    2001-01-01

    textabstractThe bankruptcy prediction problem can be considered an or dinal classification problem. The classical theory of Rough Sets describes objects by discrete attributes, and does not take into account the order- ing of the attributes values. This paper proposes a modification of the Rough Set

  4. Predicting Volleyball Serve-Reception

    NARCIS (Netherlands)

    Paulo, Ana; Zaal, Frank T J M; Fonseca, Sofia; Araujo, Duarte

    2016-01-01

    Serve and serve-reception performance have predicted success in volleyball. Given the impact of serve-reception on the game, we aimed at understanding what it is in the serve and receiver's actions that determines the selection of the type of pass used in serve-reception and its efficacy. Four

  5. Making predictions skill level analysis

    Science.gov (United States)

    Katarína, Krišková; Marián, Kireš

    2017-01-01

    The current trend in the education is focused on skills that are cross-subject and have a great importance for the pupil future life. Pupils should acquire different types of skills during their education to be prepared for future careers and life in the 21st century. Physics as a subject offers many opportunities for pupils' skills development. One of the skills that are expected to be developed in physics and also in other sciences is making predictions. The prediction, in the meaning of the argument about what may happen in the future, is an integral part of the empirical cognition, in which students confront existing knowledge and experience with new, hitherto unknown and surprising phenomena. The extent of the skill is the formulation of hypotheses, which is required in the upper secondary physics education. In the contribution, the prediction skill is specified and its eventual levels are classified. Authors focus on the tools for skill level determination based on the analysis of pupils` worksheets. Worksheets are the part of the educational activities conducted within the Inquiry Science Laboratory Steelpark. Based on the formulation of pupils' prediction the pupils thinking can be seen and their understanding of the topic, as well as preconceptions and misconceptions.

  6. Predictive medical information and underwriting.

    Science.gov (United States)

    Dodge, John H

    2007-01-01

    Medical underwriting involves the application of actuarial science by analyzing medical information to predict the future risk of a claim. The objective is that individuals with like risk are treated in a like manner so that the premium paid is proportional to the risk of future claim.

  7. Prediction models in complex terrain

    DEFF Research Database (Denmark)

    Marti, I.; Nielsen, Torben Skov; Madsen, Henrik

    2001-01-01

    The objective of the work is to investigatethe performance of HIRLAM in complex terrain when used as input to energy production forecasting models, and to develop a statistical model to adapt HIRLAM prediction to the wind farm. The features of the terrain, specially the topography, influence...

  8. Solution Patterns Predicting Pythagorean Triples

    Science.gov (United States)

    Ezenweani, Ugwunna Louis

    2013-01-01

    Pythagoras Theorem is an old mathematical treatise that has traversed the school curricula from secondary to tertiary levels. The patterns it produced are quite interesting that many researchers have tried to generate a kind of predictive approach to identifying triples. Two attempts, namely Diophantine equation and Brahmagupta trapezium presented…

  9. Prediction of Malaysian monthly GDP

    Science.gov (United States)

    Hin, Pooi Ah; Ching, Soo Huei; Yeing, Pan Wei

    2015-12-01

    The paper attempts to use a method based on multivariate power-normal distribution to predict the Malaysian Gross Domestic Product next month. Letting r(t) be the vector consisting of the month-t values on m selected macroeconomic variables, and GDP, we model the month-(t+1) GDP to be dependent on the present and l-1 past values r(t), r(t-1),…,r(t-l+1) via a conditional distribution which is derived from a [(m+1)l+1]-dimensional power-normal distribution. The 100(α/2)% and 100(1-α/2)% points of the conditional distribution may be used to form an out-of sample prediction interval. This interval together with the mean of the conditional distribution may be used to predict the month-(t+1) GDP. The mean absolute percentage error (MAPE), estimated coverage probability and average length of the prediction interval are used as the criterions for selecting the suitable lag value l-1 and the subset from a pool of 17 macroeconomic variables. It is found that the relatively better models would be those of which 2 ≤ l ≤ 3, and involving one or two of the macroeconomic variables given by Market Indicative Yield, Oil Prices, Exchange Rate and Import Trade.

  10. Predicting Noise From Wind Turbines

    Science.gov (United States)

    Grosveld, Ferdinand W.

    1990-01-01

    Computer program WINDY predicts broadband noise spectra of horizontal-axis wind-turbine generators. Enables adequate assessment of impact of broadband wind-turbine noise. Effects of turbulence, trailing-edge wakes, and bluntness taken into account. Program has practical application in design and siting of wind-turbine machines acceptable to community. Written in GW-Basic.

  11. Predicting severity of paranoid schizophrenia

    OpenAIRE

    Kolesnichenko Elena Vladimirovna

    2015-01-01

    Clinical symptoms, course and outcomes of paranoid schizophrenia are polymorphic. 206 cases of paranoid schizophrenia were investigated. Clinical predictors were collected from hospital records and interviews. Quantitative assessment of the severity of schizophrenia as special indexes was used. Schizoid, epileptoid, psychasthenic and conformal accentuation of personality in the premorbid, early onset of psychosis, paranoid and hallucinatory-paranoid variants of onset predicted more expressed ...

  12. Predictive implications of Gompertz's law

    Science.gov (United States)

    Richmond, Peter; Roehner, Bertrand M.

    2016-04-01

    Gompertz's law tells us that for humans above the age of 35 the death rate increases exponentially with a doubling time of about 10 years. Here, we show that the same law continues to hold up to age 106. At that age the death rate is about 50%. Beyond 106 there is so far no convincing statistical evidence available because the number of survivors are too small even in large nations. However, assuming that Gompertz's law continues to hold beyond 106, we conclude that the mortality rate becomes equal to 1 at age 120 (meaning that there are 1000 deaths in a population of one thousand). In other words, the upper bound of human life is near 120. The existence of this fixed-point has interesting implications. It allows us to predict the form of the relationship between death rates at age 35 and the doubling time of Gompertz's law. In order to test this prediction, we first carry out a transversal analysis for a sample of countries comprising both industrialized and developing nations. As further confirmation, we also develop a longitudinal analysis using historical data over a time period of almost two centuries. Another prediction arising from this fixed-point model, is that, above a given population threshold, the lifespan of the oldest persons is independent of the size of their national community. This prediction is also supported by empirical evidence.

  13. Predicting Leakage in Labyrinth Seals

    Science.gov (United States)

    Morrison, G. L.; Rhode, D. L.; Cogan, K. C.; Chi, D.; Demko, J.

    1985-01-01

    Analytical and empirical methods evaluated. 264-page report presents comprehensive information on leakage in labyrinth seals. Summarizes previous analyses of leakage, reviews leakage tests conducted by authors and evaluates various analytical and experimental methods of determining leakage and discusses leakage prediction techniques.

  14. Predicting Volleyball Serve-Reception

    NARCIS (Netherlands)

    Paulo, Ana; Zaal, Frank T J M; Fonseca, Sofia; Araujo, Duarte

    2016-01-01

    Serve and serve-reception performance have predicted success in volleyball. Given the impact of serve-reception on the game, we aimed at understanding what it is in the serve and receiver's actions that determines the selection of the type of pass used in serve-reception and its efficacy. Four high-

  15. Evoked Emotions Predict Food Choice

    NARCIS (Netherlands)

    Dalenberg, J.R.; Gutjar, S.; Horst, ter G.J.; Graaf, de C.; Renken, R.; Jager, G.

    2014-01-01

    In the current study we show that non-verbal food-evoked emotion scores significantly improve food choice prediction over merely liking scores. Previous research has shown that liking measures correlate with choice. However, liking is no strong predictor for food choice in real life environments. Th

  16. Can Creativity Predict Cognitive Reserve?

    Science.gov (United States)

    Palmiero, Massimiliano; Di Giacomo, Dina; Passafiume, Domenico

    2016-01-01

    Cognitive reserve relies on the ability to effectively cope with aging and brain damage by using alternate processes to approach tasks when standard approaches are no longer available. In this study, the issue if creativity can predict cognitive reserve has been explored. Forty participants (mean age: 61 years) filled out: the Cognitive Reserve…

  17. Working postures: prediction and evaluation

    NARCIS (Netherlands)

    Delleman, N.J.

    1999-01-01

    To date, workstation designers cannot see the effects of a design on working posture before a mock-up/prototype is available. At that moment, usually the margin for creating the conditions required for adopting favourable working postures is still very limited. Posture prediction at an early design

  18. Detecting failure of climate predictions

    Science.gov (United States)

    Runge, Michael C.; Stroeve, Julienne C.; Barrett, Andrew P.; McDonald-Madden, Eve

    2016-09-01

    The practical consequences of climate change challenge society to formulate responses that are more suited to achieving long-term objectives, even if those responses have to be made in the face of uncertainty. Such a decision-analytic focus uses the products of climate science as probabilistic predictions about the effects of management policies. Here we present methods to detect when climate predictions are failing to capture the system dynamics. For a single model, we measure goodness of fit based on the empirical distribution function, and define failure when the distribution of observed values significantly diverges from the modelled distribution. For a set of models, the same statistic can be used to provide relative weights for the individual models, and we define failure when there is no linear weighting of the ensemble models that produces a satisfactory match to the observations. Early detection of failure of a set of predictions is important for improving model predictions and the decisions based on them. We show that these methods would have detected a range shift in northern pintail 20 years before it was actually discovered, and are increasingly giving more weight to those climate models that forecast a September ice-free Arctic by 2055.

  19. Detecting failure of climate predictions

    Science.gov (United States)

    Runge, Michael C.; Stroeve, Julienne C.; Barrett, Andrew P.; McDonald-Madden, Eve

    2016-01-01

    The practical consequences of climate change challenge society to formulate responses that are more suited to achieving long-term objectives, even if those responses have to be made in the face of uncertainty1, 2. Such a decision-analytic focus uses the products of climate science as probabilistic predictions about the effects of management policies3. Here we present methods to detect when climate predictions are failing to capture the system dynamics. For a single model, we measure goodness of fit based on the empirical distribution function, and define failure when the distribution of observed values significantly diverges from the modelled distribution. For a set of models, the same statistic can be used to provide relative weights for the individual models, and we define failure when there is no linear weighting of the ensemble models that produces a satisfactory match to the observations. Early detection of failure of a set of predictions is important for improving model predictions and the decisions based on them. We show that these methods would have detected a range shift in northern pintail 20 years before it was actually discovered, and are increasingly giving more weight to those climate models that forecast a September ice-free Arctic by 2055.

  20. Can Creativity Predict Cognitive Reserve?

    Science.gov (United States)

    Palmiero, Massimiliano; Di Giacomo, Dina; Passafiume, Domenico

    2016-01-01

    Cognitive reserve relies on the ability to effectively cope with aging and brain damage by using alternate processes to approach tasks when standard approaches are no longer available. In this study, the issue if creativity can predict cognitive reserve has been explored. Forty participants (mean age: 61 years) filled out: the Cognitive Reserve…