Ocean General Circulation Models
Yoon, Jin-Ho; Ma, Po-Lun
2012-09-30
1. Definition of Subject The purpose of this text is to provide an introduction to aspects of oceanic general circulation models (OGCMs), an important component of Climate System or Earth System Model (ESM). The role of the ocean in ESMs is described in Chapter XX (EDITOR: PLEASE FIND THE COUPLED CLIMATE or EARTH SYSTEM MODELING CHAPTERS). The emerging need for understanding the Earth’s climate system and especially projecting its future evolution has encouraged scientists to explore the dynamical, physical, and biogeochemical processes in the ocean. Understanding the role of these processes in the climate system is an interesting and challenging scientific subject. For example, a research question how much extra heat or CO2 generated by anthropogenic activities can be stored in the deep ocean is not only scientifically interesting but also important in projecting future climate of the earth. Thus, OGCMs have been developed and applied to investigate the various oceanic processes and their role in the climate system.
Adaptive Grids for Atmospheric General Circulation Models
Jablonowski, Christiane
the wind speed OMEGA model Courtesy of A. Sarma (SAIC, NC, USA) #12;Two Adaptive Shallow Water Models AMR the vertical resolutions adds another factor of 2 We need to increase our computational power by a factor
Simulation of snow mass and extent in general circulation models
Yang, Zong-Liang
Simulation of snow mass and extent in general circulation models Zong-Liang Yang,1,2* Robert E Scheme (BATS) snow submodel was conducted, both in a stand-alone mode and within the National Center Union and from Mammoth Mountain, California. The BATS snow scheme reproduces well the seasonal evolution
Application of Improved Radiation Modeling to General Circulation Models
Michael J Iacono
2011-04-07
This research has accomplished its primary objectives of developing accurate and efficient radiation codes, validating them with measurements and higher resolution models, and providing these advancements to the global modeling community to enhance the treatment of cloud and radiative processes in weather and climate prediction models. A critical component of this research has been the development of the longwave and shortwave broadband radiative transfer code for general circulation model (GCM) applications, RRTMG, which is based on the single-column reference code, RRTM, also developed at AER. RRTMG is a rigorously tested radiation model that retains a considerable level of accuracy relative to higher resolution models and measurements despite the performance enhancements that have made it possible to apply this radiation code successfully to global dynamical models. This model includes the radiative effects of all significant atmospheric gases, and it treats the absorption and scattering from liquid and ice clouds and aerosols. RRTMG also includes a statistical technique for representing small-scale cloud variability, such as cloud fraction and the vertical overlap of clouds, which has been shown to improve cloud radiative forcing in global models. This development approach has provided a direct link from observations to the enhanced radiative transfer provided by RRTMG for application to GCMs. Recent comparison of existing climate model radiation codes with high resolution models has documented the improved radiative forcing capability provided by RRTMG, especially at the surface, relative to other GCM radiation models. Due to its high accuracy, its connection to observations, and its computational efficiency, RRTMG has been implemented operationally in many national and international dynamical models to provide validated radiative transfer for improving weather forecasts and enhancing the prediction of global climate change.
Robertson, Andrew W.
Solving Problems with GCMs: General Circulation Models and Their Role in the Climate Modeling of a hierarchy of models for solving problems in climate dynamics. General circulation models (GCMs) occupy, capture all the phenomena, and solve all the problems. Hence the concept of a hierarchy of climate models
Modelling ocean circulation processes in the MIT general circulation model using nen
Barnshaw, Heather E
2007-09-24
Previous work by Reitsma and Albrecht (2005, 2006) and Reitsma and Dubayah (2006) documented the development and implementation of a new process-based data model, called nen. This paper extends that work by applying the ...
Extension of a Martian general circulation model to thermospheric altitudes: UV heating
Forget, François
Extension of a Martian general circulation model to thermospheric altitudes: UV heating altitudes: UV heating and photochemical models, J. Geophys. Res., 110, E09008, doi:10.1029/2004JE002312. 1. Introduction [2] New modeling efforts and new data from spacecraft instrumentation are two relevant topics
The Effect of Topography on Storm-Track Intensity in a Relatively Simple General Circulation Model
Son, Seok-Woo
The Effect of Topography on Storm-Track Intensity in a Relatively Simple General Circulation Model The effect of topography on storm-track intensity is examined with a set of primitive equation model flow impinging on the topography. If the background flow consists of a weak double jet, higher
Fridlind, Ann
jcl92c.tex The Importance of Mesoscale Circulations Generated by SubgridScale Landscape Oceanography, Cook Campus, Rutgers University, New Brunswick, NJ 08903, USA. #12; Abstract A mesoscale. These results emphasize the need to parameterize mesoscale processes induced by landscape discontinuities
Burtis, M.D.; Razuvaev, V.N.; Sivachok, S.G.
1996-10-01
This report presents English-translated abstracts of important Russian-language literature concerning general circulation models as they relate to climate change. Into addition to the bibliographic citations and abstracts translated into English, this report presents the original citations and abstracts in Russian. Author and title indexes are included to assist the reader in locating abstracts of particular interest.
Impact Assessment of Satellite-Derived Leaf Area Index Datasets Using a General Circulation Model
Xue, Yongkang
Impact Assessment of Satellite-Derived Leaf Area Index Datasets Using a General Circulation Model the impact of two different remote sensingderived leaf area index (RSLAI) datasets retrieved from the same using the RSLAI and other satellite-derived land surface products showed sub- stantial improvements
Investigating the ability of general circulation models to capture the effects of Eurasian snow of general circulation models (GCMs) to reproduce the observed strong correlations of Eurasian snow extent in the troposphere in response to snow-forced surface cooling and a coupled zonal-mean stratosphere
Fesen, C.G. (Dartmouth College, Hanover, NH (United States)); Roble, R.G.; Ridley, E.C. (National Center for Atmospheric Research, Boulder, CO (United States))
1993-05-01
The authors use the National Center for Atmospheric Research (NCAR) thermosphere/ionosphere general circulation model (TIGCM) to model tides and dynamics in the thermosphere. This model incorporates the latest advances in the thermosphere general circulation model. Model results emphasized the 70[degree] W longitude region to overlap a series of incoherent radar scatter installations. Data and the model are available on data bases. The results of this theoretical modeling are compared with available data, and with prediction of more empirical models. In general there is broad agreement within the comparisons.
Kim, Joong Tae
2007-09-17
Open water in sea ice, such as leads and polynyas, plays a crucial role in determining the formation of deep- and bottom-water, as well as their long-term global properties and circulation. Ocean general circulation models (GCMs) designed...
Thornton, P. E.; Doney, S. C.; Lindsay, Keith; Moore, J. K.; Mahowald, N. M.; Randerson, J. T.; Fung, I.; Lamarque, J. F.; Feddema, Johannes J.
2009-01-01
Abstract. Inclusion of fundamental ecological interactions between carbon and nitrogen cycles in the land component of an atmosphere-ocean general circulation model (AOGCM) leads to decreased carbon uptake associated ...
Electrodynamic effects of thermospheric winds from the NCAR thermospheric general circulation model
Richmond, A.D.; Roble, R.G.
1987-11-01
The ionospheric electric fields and currents and the associated ground magnetic variations, generated by the dynamo action of winds simulated with the National Center for Atmospheric Research, Boulder, Colo. (NCAR) Thermospheric General Circulation Model (TGCM), are modelled and compared with observations for equinox solar minimum conditions. The dynamo model uses a tilted dipole geomagnetic field and allows for field-aligned current flow between conjugate points, but no magnetospheric dynamo effects are included. Two TGCM wind simulations are used, one of which is driven only by in situ solar ultraviolet heating and the other of which includes lower boundary forcing that mimics the effects of upward propagating semidiurnal tides, as described by Fesen et al. (1986). Without tidal forcing, the TGCM winds produce ground magnetic variations that have the general pattern of observed Sq variations but are only about half as strong.
Collett Jr., Jeffrey L.
Convective Precipitation Variability as a Tool for General Circulation Model Analysis CHARLOTTE A Precipitation variability is analyzed in two versions of the Community Atmospheric Model (CAM), the standard rainfall as soon as the boundary layer energizes. Precipitation is also concurrent with tropospheric
Ocean mixed layer processes in the Pacific Decadal Oscillation in coupled general circulation models
Qiu, Bo
Ocean mixed layer processes in the Pacific Decadal Oscillation in coupled general circulation to be larger for CGCMs with a larger ocean heat transport in the region. Keywords Pacific Decadal Oscillation Á. 1994a, b; Zhanget al. 1996), ocean-atmosphere interactions over the North Pacific (e.g., Latif
A comparison of general circulation model predictions to sand drift and dune orientations
Blumberg, D.G.; Greeley, R.
1996-12-01
The growing concern over climate change and decertification stresses the importance of aeolian process prediction. In this paper the use of a general circulation model to predict current aeolian features is examined. A GCM developed at NASA/Goddard Space Flight Center was used in conjunction with White`s aeolian sand flux model to produce a global potential aeolian transport map. Surface wind shear stress predictions were used from the output of a GCM simulation that was performed as part of the Atmospheric Model Intercomparison Project on 1979 climate conditions. The spatial resolution of this study (as driven by the GCM) is 4{degrees} X 5{degrees}; instantaneous 6-hourly wind stress data were saved by the GCM and used in this report. A global map showing potential sand transport was compared to drift potential directions as inferred from Landsat images from the 1980s for several sand seas and a coastal dune field. Generally, results show a good correlation between the simulated sand drift direction and the drift direction inferred for dune forms. Discrepancies between the drift potential and the drift inferred from images were found in the North American deserts and the Arabian peninsula. An attempt to predict the type of dune that would be formed in specific regions was not successful. The model could probably be further improved by incorporating soil moisture, surface roughness, and vegetation information for a better assessment of sand threshold conditions. The correlation may permit use of a GCM to analyze {open_quotes}fossil{close_quotes} dunes or to forecast aeolian processes. 48 refs., 8 figs.
Wan, Hui; Rasch, Philip J.; Zhang, Kai; Qian, Yun; Yan, Huiping; Zhao, Chun
2014-09-08
This paper explores the feasibility of an experimentation strategy for investigating sensitivities in fast components of atmospheric general circulation models. The basic idea is to replace the traditional serial-in-time long-term climate integrations by representative ensembles of shorter simulations. The key advantage of the proposed method lies in its efficiency: since fewer days of simulation are needed, the computational cost is less, and because individual realizations are independent and can be integrated simultaneously, the new dimension of parallelism can dramatically reduce the turnaround time in benchmark tests, sensitivities studies, and model tuning exercises. The strategy is not appropriate for exploring sensitivity of all model features, but it is very effective in many situations. Two examples are presented using the Community Atmosphere Model version 5. The first example demonstrates that the method is capable of characterizing the model cloud and precipitation sensitivity to time step length. A nudging technique is also applied to an additional set of simulations to help understand the contribution of physics-dynamics interaction to the detected time step sensitivity. In the second example, multiple empirical parameters related to cloud microphysics and aerosol lifecycle are perturbed simultaneously in order to explore which parameters have the largest impact on the simulated global mean top-of-atmosphere radiation balance. Results show that in both examples, short ensembles are able to correctly reproduce the main signals of model sensitivities revealed by traditional long-term climate simulations for fast processes in the climate system. The efficiency of the ensemble method makes it particularly useful for the development of high-resolution, costly and complex climate models.
Phillips, T J; Potter, G L; Williamson, D L; Cederwall, R T; Boyle, J S; Fiorino, M; Hnilo, J J; Olson, J G; Xie, S; Yio, J J
2004-05-06
To significantly improve the simulation of climate by general circulation models (GCMs), systematic errors in representations of relevant processes must first be identified, and then reduced. This endeavor demands that the GCM parameterizations of unresolved processes, in particular, should be tested over a wide range of time scales, not just in climate simulations. Thus, a numerical weather prediction (NWP) methodology for evaluating model parameterizations and gaining insights into their behavior may prove useful, provided that suitable adaptations are made for implementation in climate GCMs. This method entails the generation of short-range weather forecasts by a realistically initialized climate GCM, and the application of six-hourly NWP analyses and observations of parameterized variables to evaluate these forecasts. The behavior of the parameterizations in such a weather-forecasting framework can provide insights on how these schemes might be improved, and modified parameterizations then can be tested in the same framework. In order to further this method for evaluating and analyzing parameterizations in climate GCMs, the U.S. Department of Energy is funding a joint venture of its Climate Change Prediction Program (CCPP) and Atmospheric Radiation Measurement (ARM) Program: the CCPP-ARM Parameterization Testbed (CAPT). This article elaborates the scientific rationale for CAPT, discusses technical aspects of its methodology, and presents examples of its implementation in a representative climate GCM.
Passive tracers in a general circulation model of the Southern Ocean I. G. Stevens, D. P. Stevens
Stevens, David
Passive tracers in a general circulation model of the Southern Ocean I. G. Stevens, D. P. Stevens: 22 January 1999 / Accepted: 12 February 1999 Abstract. Passive tracers are used in an o-line version and provide information on the inter-ocean exchange of water masses. The use of passive tracers allows
Gnanadesikan, Anand
shortwave penetration in the high-latitude Southern Ocean causes an increase in the formation of mode waterOcean Water Clarity and the Ocean General Circulation in a Coupled Climate Model ANAND GNANADESIKAN Jersey (Manuscript received 11 October 2007, in final form 17 July 2008) ABSTRACT Ocean water clarity
Forced and free variations of the surface temperature field in a general circulation model
North, G.R.; Yip, K.J.J.; Laiyung Leung (Texas A M Univ., College Station (United States)); Chervin, R.M. (National Center for Atmospheric Research, Boulder, CO (United States))
1992-03-01
The concept of forced' and free' variations of large-scale surface temperature is examined by analyzing several long runs of the Community Climate Model (CCM0) with idealized boundary conditions and forcing. (1) The planet is all land with uniform sea-level topography and fixed soil moisture. (2) The planetary surface and prescribed ozone are reflection symmetric across the equator and there is no generation of snow. (3) The obliquity is set to zero so that the climate is for a perpetual equinox solar insolation (i.e., sun fixed over the equator). After examining some relevant aspects of the undisturbed climate (surface temperature field) such as temporal and spatial autocorrelations and the corresponding spectra, two types of changes in external forcing are imposed to study the model response: (1) sinusoidal changes of the solar constant (5%, 10%, 20%, and 40% amplitudes) at periods of 15 and 30 days (the latter is the autocorrelation time for the global average surface temperature) and 20% at 60 days and (2) insertion of steady heat sources (points and zonal bands) of variable strength at the surface. Then the temporal spectra of large scales for the periodically forced climate and the ensemble-averaged influence functions are examined for the point source disturbed climates. In each class of experiments the response of ensemble-averaged amplitudes was found to be proportional to the amplitude of the forcing. These results suggest that the lowest moments of the surface temperature field have a particularly simple dependence on forcing. Furthermore, the apparent finiteness of the variance spectrum at low frequencies suggest that estimates of long-term statistics are stable in this type of atmospheric general circulation model. 31 refs., 17 figs.
Shackley, Simon.; Risbey, James; Stone, Peter H.; Wynne, Brian
This paper surveys and interprets the attitudes of scientists to the use of flux adjustments in climate projections with coupled Atmosphere Ocean General Circulation Models. The survey is based largely on the responses of ...
Quaas, Johannes; Ming, Yi; Menon, Surabi; Takemura, Toshihiko; Wang, Minghuai; Penner, Joyce E.; Gettelman, Andrew; Lohmann, Ulrike; Bellouin, Nicolas; Boucher, Olivier; Sayer, Andrew M.; Thomas, Gareth E.; McComiskey, Allison; Feingold, Graham; Hoose, Corinna; Kristjansson, Jon Egill; Liu, Xiaohong; Balkanski, Yves; Donner, Leo J.; Ginoux, Paul A.; Stier, Philip; Feichter, Johann; Sednev, Igor; Bauer, Susanne E.; Koch, Dorothy; Grainger, Roy G.; Kirkevag, Alf; Iversen, Trond; Seland, Oyvind; Easter, Richard; Ghan, Steven J.; Rasch, Philip J.; Morrison, Hugh; Lamarque, Jean-Francois; Iacono, Michael J.; Kinne, Stefan; Schulz, Michael
2009-04-10
Aerosol indirect effects continue to constitute one of the most important uncertainties for anthropogenic climate perturbations. Within the international AEROCOM initiative, the representation of aerosol-cloud-radiation interactions in ten different general circulation models (GCMs) is evaluated using three satellite datasets. The focus is on stratiform liquid water clouds since most GCMs do not include ice nucleation effects, and none of the model explicitly parameterizes aerosol effects on convective clouds. We compute statistical relationships between aerosol optical depth (Ta) and various cloud and radiation quantities in a manner that is consistent between the models and the satellite data. It is found that the model-simulated influence of aerosols on cloud droplet number concentration (Nd) compares relatively well to the satellite data at least over the ocean. The relationship between Ta and liquid water path is simulated much too strongly by the models. It is shown that this is partly related to the representation of the second aerosol indirect effect in terms of autoconversion. A positive relationship between total cloud fraction (fcld) and Ta as found in the satellite data is simulated by the majority of the models, albeit less strongly than that in the satellite data in most of them. In a discussion of the hypotheses proposed in the literature to explain the satellite-derived strong fcld - Ta relationship, our results indicate that none can be identified as unique explanation. Relationships similar to the ones found in satellite data between Ta and cloud top temperature or outgoing long-wave radiation (OLR) are simulated by only a few GCMs. The GCMs that simulate a negative OLR - Ta relationship show a strong positive correlation between Ta and fcld The short-wave total aerosol radiative forcing as simulated by the GCMs is strongly influenced by the simulated anthropogenic fraction of Ta, and parameterisation assumptions such as a lower bound on Nd. Nevertheless, the strengths of the statistical relationships are good predictors for the aerosol forcings in the models. An estimate of the total short-wave aerosol forcing inferred from the combination of these predictors for the modelled forcings with the satellite-derived statistical relationships yields a global annual mean value of -1.5+-0.5 Wm-2. An alternative estimate obtained by scaling the simulated clear- and cloudy-sky forcings with estimates of anthropogenic Ta and satellite-retrieved Nd - Ta regression slopes, respectively, yields a global annual mean clear-sky (aerosol direct effect) estimate of -0.4+-0.2 Wm-2 and a cloudy-sky (aerosol indirect effect) estimate of -0.7+-0.5 Wm-2, with a total estimate of -1.2+-0.4 Wm-2.
Quaas, Johannes; Ming, Yi; Menon, Surabi; Takemura, Toshihiko; Wang, Minghuai; Penner, Joyce E.; Gettelman, Andrew; Lohmann, Ulrike; Bellouin, Nicolas; Boucher, Olivier; Sayer, Andrew M.; Thomas, Gareth E.; McComiskey, Allison; Feingold, Graham; Hoose, Corinna; Kristansson, Jon Egill; Liu, Xiaohong; Balkanski, Yves; Donner, Leo J.; Ginoux, Paul A.; Stier, Philip; Grandey, Benjamin; Feichter, Johann; Sednev, Igor; Bauer, Susanne E.; Koch, Dorothy; Grainger, Roy G.; Kirkevag, Alf; Iversen, Trond; Seland, Oyvind; Easter, Richard; Ghan, Steven J.; Rasch, Philip J.; Morrison, Hugh; Lamarque, Jean-Francois; Iacono, Michael J.; Kinne, Stefan; Schulz, Michael
2010-03-12
Aerosol indirect effects continue to constitute one of the most important uncertainties for anthropogenic climate perturbations. Within the international AEROCOM initiative, the representation of aerosol-cloud-radiation interactions in ten different general circulation models (GCMs) is evaluated using three satellite datasets. The focus is on stratiform liquid water clouds since most GCMs do not include ice nucleation effects, and none of the model explicitly parameterises aerosol effects on convective clouds. We compute statistical relationships between aerosol optical depth ({tau}{sub a}) and various cloud and radiation quantities in a manner that is consistent between the models and the satellite data. It is found that the model-simulated influence of aerosols on cloud droplet number concentration (N{sub d}) compares relatively well to the satellite data at least over the ocean. The relationship between {tau}{sub a} and liquid water path is simulated much too strongly by the models. This suggests that the implementation of the second aerosol indirect effect mainly in terms of an autoconversion parameterisation has to be revisited in the GCMs. A positive relationship between total cloud fraction (f{sub cld}) and {tau}{sub a} as found in the satellite data is simulated by the majority of the models, albeit less strongly than that in the satellite data in most of them. In a discussion of the hypotheses proposed in the literature to explain the satellite-derived strong f{sub cld} - {tau}{sub a} relationship, our results indicate that none can be identified as a unique explanation. Relationships similar to the ones found in satellite data between {tau}{sub a} and cloud top temperature or outgoing long-wave radiation (OLR) are simulated by only a few GCMs. The GCMs that simulate a negative OLR - {tau}{sub a} relationship show a strong positive correlation between {tau}{sub a} and f{sub cld} The short-wave total aerosol radiative forcing as simulated by the GCMs is strongly influenced by the simulated anthropogenic fraction of {tau}{sub a}, and parameterization assumptions such as a lower bound on N{sub d}. Nevertheless, the strengths of the statistical relationships are good predictors for the aerosol forcings in the models. An estimate of the total short-wave aerosol forcing inferred from the combination of these predictors for the modelled forcings with the satellite-derived statistical relationships yields a global annual mean value of -1.5 {+-} 0.5 Wm{sup -2}. In an alternative approach, the radiative flux perturbation due to anthropogenic aerosols can be broken down into a component over the cloud-free portion of the globe (approximately the aerosol direct effect) and a component over the cloudy portion of the globe (approximately the aerosol indirect effect). An estimate obtained by scaling these simulated clear- and cloudy-sky forcings with estimates of anthropogenic {tau}{sub a} and satellite-retrieved Nd - {tau}{sub a} regression slopes, respectively, yields a global, annual-mean aerosol direct effect estimate of -0.4 {+-} 0.2 Wm{sup -2} and a cloudy-sky (aerosol indirect effect) estimate of -0.7 {+-} 0.5 Wm{sup -2}, with a total estimate of -1.2 {+-} 0.4 Wm{sup -2}.
Zalucha, Angela
2012-01-01
We present a 3D general circulation model of Pluto and Triton's atmospheres, which uses radiative-conductive-convective forcing. In both the Pluto and Triton models, an easterly (prograde) jet is present at the equator with a maximum magnitude of 10-12 m/s and 4 m/s, respectively. Neither atmosphere shows any significant overturning circulation in the meridional and vertical directions. Rather, it is horizontal motions (mean circulation and transient waves) that transport heat meridionally at a magnitude of 1 and 3 x 10^7 W at Pluto's autumn equinox and winter solstice, respectively (seasons referenced to the Northern Hemisphere). The meridional and dayside-nightside temperature contrast is small (<5 K). We find that the lack of vertical motion can be explained on Pluto by the strong temperature inversion in the lower atmosphere. The height of the Voyager 2 plumes on Triton can be explained by the dynamical properties of the lower atmosphere alone (i.e., strong wind shear) and does not require a thermally ...
USE OF GENERAL CIRCULATION MODEL OUTPUT IN THE CREATION OF CLIMATE CHANGE SCENARIOS
Robock, Alan
, Sub-Saharan Africa and Venezuela, for use in biological effects models. By combining the general, and possible solar variations, and all agree that surface air temperatures will rise, pre- cipitation patterns will change, and sea level will rise. Even though such projections of the future are relatively crude
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Saenz, Juan A.; Chen, Qingshan; Ringler, Todd
2015-05-19
Recent work has shown that taking the thickness-weighted average (TWA) of the Boussinesq equations in buoyancy coordinates results in exact equations governing the prognostic residual mean flow where eddy–mean flow interactions appear in the horizontal momentum equations as the divergence of the Eliassen–Palm flux tensor (EPFT). It has been proposed that, given the mathematical tractability of the TWA equations, the physical interpretation of the EPFT, and its relation to potential vorticity fluxes, the TWA is an appropriate framework for modeling ocean circulation with parameterized eddies. The authors test the feasibility of this proposition and investigate the connections between the TWAmore »framework and the conventional framework used in models, where Eulerian mean flow prognostic variables are solved for. Using the TWA framework as a starting point, this study explores the well-known connections between vertical transfer of horizontal momentum by eddy form drag and eddy overturning by the bolus velocity, used by Greatbatch and Lamb and Gent and McWilliams to parameterize eddies. After implementing the TWA framework in an ocean general circulation model, we verify our analysis by comparing the flows in an idealized Southern Ocean configuration simulated using the TWA and conventional frameworks with the same mesoscale eddy parameterization.« less
Kuroda, Takeshi; Yi?it, Erdal; Hartogh, Paul
2015-01-01
Global characteristics of the small-scale gravity wave (GW) field in the Martian atmosphere obtained from a high-resolution general circulation model (GCM) are presented for the first time. The simulated GW-induced temperature variances are in a good agreement with available radio occultation data in the lower atmosphere between 10 and 30 km. The model reveals a latitudinal asymmetry with stronger wave generation in the winter hemisphere, and two distinctive sources of GWs: mountainous regions and the meandering winter polar jet. Orographic GWs are filtered while propagating upward, and the mesosphere is primarily dominated by harmonics with faster horizontal phase velocities. Wave fluxes are directed mainly against the local wind. GW dissipation in the upper mesosphere generates body forces of tens of m~s$^{-1}$~sol$^{-1}$, which tend to close the simulated jets. The results represent a realistic surrogate for missing observations, which can be used for constraining GW parameterizations and validating GCM si...
Whetton, P.H.; Pittock, A.B.; Haylock, M.R. ); Rayner, P.J. )
1994-03-01
To assist in estimating likely future climate change in the Australian region, the authors examine the results of four different general circulation modeling experiments run to assess the equilibrium impact of doubling greenhouse gases. The results examined were the most recent available at the time of study from various research centers in North America and Europe, as well as those of the Commonwealth Scientific and Industrial Research Organisation (CSIRO). The approach used is, first, to assess the quality of the control (1 x CO[sub 2]) simulations from each of the models of mean sea level (MSL) pressure and precipitation in the Australian region by comparing these with the corresponding observed patterns; and, second, to then analyze the 2 x CO[sub 2] results of only those model experiments with the best control simulations. Of the models examined two are chosen on the basis of their simulation of current climate in the region: the CSIRO four-level model (CSIRO4) and the United Kingdom Meteorological Office (UKMO) model. For conditions of equivalent doubling of CO[sub 2], both models show substantial increases in surface air temperature of around 4[degrees]-6[degrees] inland and 2[degrees]-4[degrees]C in coastal regions. Both models show decreased MSL pressure over the Australian continent and increases in rainfall over northern, central, and eastern Australia, particularly in the summer half of the year. The CSIRO4 model, but not the UKMO model, also shows increased pressure to the south of the continent and decreased winter rainfall in southwest and southern Australia. Generally, field significance tests show the pattern and magnitude of the changes to be significant of CSIRO4 (for which the necessary monthly simulated data were available). 42 refs., 20 figs., 5 tabs.
Robert G. Ellingson
2004-09-28
One specific goal of the Atmospheric Radiation Measurements (ARM) program is to improve the treatment of radiative transfer in General Circulation Models (GCMs) under clear-sky, general overcast and broken cloud conditions. Our project was geared to contribute to this goal by attacking major problems associated with one of the dominant radiation components of the problem --longwave radiation. The primary long-term project objectives were to: (1) develop an optimum longwave radiation model for use in GCMs that has been calibrated with state-of-the-art observations for clear and cloudy conditions, and (2) determine how the longwave radiative forcing with an improved algorithm contributes relatively in a GCM when compared to shortwave radiative forcing, sensible heating, thermal advection and convection. The approach has been to build upon existing models in an iterative, predictive fashion. We focused on comparing calculations from a set of models with operationally observed data for clear, overcast and broken cloud conditions. The differences found through the comparisons and physical insights have been used to develop new models, most of which have been tested with new data. Our initial GCM studies used existing GCMs to study the climate model-radiation sensitivity problem. Although this portion of our initial plans was curtailed midway through the project, we anticipate that the eventual outcome of this approach will provide both a better longwave radiative forcing algorithm and from our better understanding of how longwave radiative forcing influences the model equilibrium climate, how improvements in climate prediction using this algorithm can be achieved.
Sokolov, Andrei P.
Conducting probabilistic climate projections with a particular climate model requires the ability to vary the model’s characteristics, such as its climate sensitivity. In this study, the authors implement and validate a ...
Arumugam, Sankar
Improving Groundwater Predictions Utilizing Seasonal Precipitation Forecasts from General. The research reported in this paper evaluates the potential in developing 6-month-ahead groundwater Surface Temperature forecasts. Ten groundwater wells and nine streamgauges from the USGS Groundwater
Upward Shift of the Atmospheric General Circulation under Global Warming: Theory and Simulations
Singh, Martin Simran
Many features of the general circulation of the atmosphere shift upward in response to warming in simulations of climate change with both general circulation models (GCMs) and cloud-system-resolving models. The importance ...
Petascale Atmospheric General Circulation Models R. D. Nair and H. M. Tufo#
Nair, Ramachandran D.
) into an Earth system model will require a highly scalable and accurate flux-form formulation of the dynamics
Cloud/Aerosol Parameterizations: Application and Improvement of General Circulation Models
Penner, Joyce
2012-06-30
One of the biggest uncertainties associated with climate models and climate forcing is the treatment of aerosols and their effects on clouds. The effect of aerosols on clouds can be divided into two components: The first indirect effect is the forcing associated with increases in droplet concentrations; the second indirect effect is the forcing associated with changes in liquid water path, cloud morphology, and cloud lifetime. Both are highly uncertain. This project applied a cloud-resolving model to understand the response of clouds under a variety of conditions to changes in aerosols. These responses are categorized according to the large-scale meteorological conditions that lead to the response. Meteorological conditions were sampled from various fields, which, together with a global aerosol model determination of the change in aerosols from present day to pre-industrial conditions, was used to determine a first order estimate of the response of global cloud fields to changes in aerosols. The response of the clouds in the NCAR CAM3 GCM coupled to our global aerosol model were tested by examining whether the response is similar to that of the cloud resolving model and methods for improving the representation of clouds and cloud/aerosol interactions were examined.
NOAA Technical Memorandum ERL GLERL-16 A GENERAL CIRCULATION MODEL FOR LAKES
Stability 4.5 Energy Conservation PRELIMINARY RESULTS SUMMARY AND CONCLUSIONS . ACKNOWLEDGMENTS REFERENCES of prognostic variables. Vertically integrated transport function under the south- westerly wind. Time evolution of the kinetic energy in the Lake Ontario model; (a) Total kinetic energy, (b) Kinetic energy of the barorropic
Accelerated simulation of passive tracers in ocean circulation models
Khatiwala, Samar
to be particularly powerful tools when combined with ocean general circulation models (GCMs). (See England and Maier's circulation, such as the poleward transport of heat, water mass transfor- mation and ventilation
Ellingson, R.G.; Baer, F.
1998-09-01
DOE has launched a major initiative -- the Atmospheric Radiation Measurements (ARM) Program -- directed at improving the parameterization of the physics governing cloud and radiative processes in general circulation models (GCMs). One specific goal of ARM is to improve the treatment of radiative transfer in GCMs under clear-sky, general overcast and broken cloud conditions. In 1990, the authors proposed to contribute to this goal by attacking major problems connected with one of the dominant radiation components of the problem -- longwave radiation. In particular, their long-term research goals are to: develop an optimum longwave radiation model for use in GCMs that has been calibrated with state-of-the-art observations, assess the impact of the longwave radiative forcing in a GCM, determine the sensitivity of a GCM to the radiative model used in it, and determine how the longwave radiative forcing contributes relatively when compared to shortwave radiative forcing, sensible heating, thermal advection and expansion.
Roble, R.G.; Ridley, E.C.
1994-03-15
A new simulation model of the mesosphere, thermosphere, and ionosphere with coupled electrodynamics has been developed and used to calculate the global circulation, temperature and compositional structure between 30-500 km for equinox, solar cycle minimum, geomagnetic quiet conditions. The model incorporates all of the features of the NCAR thermosphere-ionosphere-electrodynamics general circulation model (TIE-GCM) but the lower boundary has been extended downward from 97 to 30 km (10 mb) and it includes the physical and chemical processes appropriate for the mesosphere and upper stratosphere. The first simulation used Rayleigh friction to represent gravity wave drag in the middle atmosphere and although it was able to close the mesospheric jets it severely damped the diurnal tide. Reduced Rayleigh friction allowed the tide to penetrate to thermospheric heights but did not close the jets. A gravity wave parameterization developed by Fritts and Lu allows both features to exist simultaneously with the structure of tides and mean flow dependent upon the strength of the gravity wave source. The model calculates a changing dynamic structure with the mean flow and diurnal tide dominant in the mesosphere, the in-situ generated semi-diurnal tide dominating the lower thermosphere and an in-situ generated diurnal tide in the upper thermosphere. The results also show considerable interaction between dynamics and composition, especially atomic oxygen between 85 and 120 km. 31 refs., 3 figs.
Ellingson, R.G.; Baer, F.
1993-12-31
This report summarizes the activities of our group to meet our stated objectives. The report is divided into sections entitled: Radiation Model Testing Activities, General Circulation Model Testing Activities, Science Team Activities, and Publications, Presentations and Meetings. The section on Science Team Activities summarizes our participation with the science team to further advance the observation and modeling programs. Appendix A lists graduate students supported, and post-doctoral appointments during the project. Reports on the activities during each of the first two years are included as Appendix B. Significant progress has been made in: determining the ability of line-by-line radiation models to calculate the downward longwave flux at the surface; determining the uncertainties in calculated the downwelling radiance and flux at the surface associated with the use of different proposed profiling techniques; intercomparing clear-sky radiance and flux observations with calculations from radiation codes from different climate models; determining the uncertainties associated with estimating N* from surface longwave flux observations; and determining the sensitivity of model calculations to different formulations of the effects of finite sized clouds.
Boyle, J.S.
1994-11-01
Divergence and convergence centers at 200 hPa and mean sea level pressure (MSLP) cyclones were located every 6 hr for a 10-yr general circulation model (GCM) simulation with the ECMWF (Cycle 36) for the boreal winters from 1980 to 1988. The simulation used the observed monthly mean sea surface temperature (SST) for the decade. Analysis of the frequency, location, and strength of these centers and cyclones gives insight into the dynamical response of the model to the varying SST. The results indicate that (1) the model produces reasonable climatologies of upper-level divergence and MSLP cyclones; (2) the model distribution of anomalies of divergence and convergence centers and MSLP cyclones is consistent with observations for the 1982-83 and 1986-87 El Nifio events; (3) the tropical Indian Ocean is the region of greatest divergence activity and interannual variability in the model; (4) the variability of the divergence centers is greater than that of the convergence centers; (5) strong divergence centers occur chiefly over the ocean in the midlatitudes but are more land-based in the tropics, except in the Indian Ocean; and (6) locations of divergence and convergence centers can be a useful tool for the intercomparison of global atmospheric simulations.
Water isotopes and the general circulation
Noone, David
quantities are equator to pole temperature gradient, and the vertical thermal stratification #12;Isotopic" is the fractionation factor is a function of temperature F depends on large scale circulation and thermal state Both, temperature gradient/condensation) 2. Entrainment of non-depleted water (humidity, stratification/sheer) #12
Climatic variations of the work done by the wind on the ocean's general circulation
Naveira Garabato, Alberto
Climatic variations of the work done by the wind on the ocean's general circulation J. M for the deep overturning circulation. In a coarse-resolution ocean model, northward-shifted winds increase Circumpolar Current (ACC). Alternatively, energy supply is diminished by southward-shifted winds, primarily
On the Wind Power Input to the Ocean General Circulation
Zhai, Xiaoming
The wind power input to the ocean general circulation is usually calculated from the time-averaged wind products. Here, this wind power input is reexamined using available observations, focusing on the role of the synoptically ...
Tao, Wei-Kuo; Houze, Robert, A., Jr.; Zeng, Xiping
2013-03-14
This three-year project, in cooperation with Professor Bob Houze at University of Washington, has been successfully finished as planned. Both ARM (the Atmospheric Radiation Measurement Program) data and cloud-resolving model (CRM) simulations were used to identify the water budgets of clouds observed in two international field campaigns. The research results achieved shed light on several key processes of clouds in climate change (or general circulation models), which are summarized below. 1. Revealed the effect of mineral dust on mesoscale convective systems (MCSs) Two international field campaigns near a desert and a tropical coast provided unique data to drive and evaluate CRM simulations, which are TWP-ICE (the Tropical Warm Pool International Cloud Experiment) and AMMA (the African Monsoon Multidisciplinary Analysis). Studies of the two campaign data were contrasted, revealing that much mineral dust can bring about large MCSs via ice nucleation and clouds. This result was reported as a PI presentation in the 3rd ASR Science Team meeting held in Arlington, Virginia in March 2012. A paper on the studies was published in the Journal of the Atmospheric Sciences (Zeng et al. 2013). 2. Identified the effect of convective downdrafts on ice crystal concentration Using the large-scale forcing data from TWP-ICE, ARM-SGP (the Southern Great Plains) and other field campaigns, Goddard CRM simulations were carried out in comparison with radar and satellite observations. The comparison between model and observations revealed that convective downdrafts could increase ice crystal concentration by up to three or four orders, which is a key to quantitatively represent the indirect effects of ice nuclei, a kind of aerosol, on clouds and radiation in the Tropics. This result was published in the Journal of the Atmospheric Sciences (Zeng et al. 2011) and summarized in the DOE/ASR Research Highlights Summaries (see http://www.arm.gov/science/highlights/RMjY5/view). 3. Used radar observations to evaluate model simulations In cooperation with Profs. Bob Houze at University of Washington and Steven Rutledge at Colorado State University, numerical model results were evaluated with observations from W- and C-band radars and CloudSat/TRMM satellites. These studies exhibited some shortcomings of current numerical models, such as too little of thin anvil clouds, directing the future improvement of cloud microphysics parameterization in CRMs. Two papers of Powell et al (2012) and Zeng et al. (2013), summarizing these studies, were published in the Journal of the Atmospheric Sciences. 4. Analyzed the water budgets of MCSs Using ARM data from TWP-ICE, ARM-SGP and other field campaigns, the Goddard CRM simulations were carried out to analyze the water budgets of clouds from TWP-ICE and AMMA. The simulations generated a set of datasets on clouds and radiation, which are available http://cloud.gsfc.nasa.gov/. The cloud datasets were available for modelers and other researchers aiming to improve the representation of cloud processes in multi-scale modeling frameworks, GCMs and climate models. Special datasets, such as 3D cloud distributions every six minutes for TWP-ICE, were requested and generated for ARM/ASR investigators. Data server records show that 86,206 datasets were downloaded by 120 users between April of 2010 and January of 2012. 5. MMF simulations The Goddard MMF (multi-scale modeling framework) has been improved by coupling with the Goddard Land Information System (LIS) and the Goddard Earth Observing System Model, Version 5 (GOES5). It has also been optimized on NASA HEC supercomputers and can be run over 4000 CPUs. The improved MMF with high horizontal resolution (1 x 1 degree) is currently being applied to cases covering 2005 and 2006. The results show that the spatial distribution pattern of precipitation rate is well simulated by the MMF through comparisons with satellite retrievals from the CMOPRH and GPCP data sets. In addition, the MMF results were compared with three reanalyses (MERRA, ERA-Interim and CFSR). Although the MMF tends
Predictive models of circulating fluidized bed combustors
Gidaspow, D.
1992-07-01
Steady flows influenced by walls cannot be described by inviscid models. Flows in circulating fluidized beds have significant wall effects. Particles in the form of clusters or layers can be seen to run down the walls. Hence modeling of circulating fluidized beds (CFB) without a viscosity is not possible. However, in interpreting Equations (8-1) and (8-2) it must be kept in mind that CFB or most other two phase flows are never in a true steady state. Then the viscosity in Equations (8-1) and (8-2) may not be the true fluid viscosity to be discussed next, but an Eddy type viscosity caused by two phase flow oscillations usually referred to as turbulence. In view of the transient nature of two-phase flow, the drag and the boundary layer thickness may not be proportional to the square root of the intrinsic viscosity but depend upon it to a much smaller extent. As another example, liquid-solid flow and settling of colloidal particles in a lamella electrosettler the settling process is only moderately affected by viscosity. Inviscid flow with settling is a good first approximation to this electric field driven process. The physical meaning of the particulate phase viscosity is described in detail in the chapter on kinetic theory. Here the conventional derivation resented in single phase fluid mechanics is generalized to multiphase flow.
Collett Jr., Jeffrey L.
NASA's new modeling framework for integrating cloud processes explicitly within each grid column, AND SIMPSON--Laboratory for Atmospheres, NASA Goddard Space Flight Center, Greenbelt, Maryland; CHERN--Laboratory for Atmospheres, NASA Goddard Space Flight Center, Greenbelt, and Goddard Earth Sciences and Technology Center
MPO 665: General Circulation of the Atmosphere Spring 2007
Miami, University of
: dnolan@rsmas.miami.edu; phone: 305-421-4930 MSC 329, Mondays and Wednesdays, 10:40-12:10 Topics: I Circulation A. Radiation, temperature, pressure, winds, moisture B. The oceans, land, ice, and their effects C climate models B. Hadley cell models C. First look at wave and eddy transports D. Zonally averaged heat
Dansereau, Véronique
2012-01-01
Interactions between the ocean circulation in sub-ice shelf cavities and the overlying ice shelf have received considerable attention in the context of observed changes in flow speeds of marine ice sheets around Antarctica. ...
Stachnik, Justin Paul
2013-03-25
This dissertation presents a series of work related to the representation of the Hadley circulation (HC) in atmospheric reanalyses and general circulation models (GCMs), with connections to the underlying tropical and ...
Houze, Jr., Robert A.
2013-11-13
We examined cloud radar data in monsoon climates, using cloud radars at Darwin in the Australian monsoon, on a ship in the Bay of Bengal in the South Asian monsoon, and at Niamey in the West African monsoon. We followed on with a more in-depth study of the continental MCSs over West Africa. We investigated whether the West African anvil clouds connected with squall line MCSs passing over the Niamey ARM site could be simulated in a numerical model by comparing the observed anvil clouds to anvil structures generated by the Weather Research and Forecasting (WRF) mesoscale model at high resolution using six different ice-phase microphysical schemes. We carried out further simulations with a cloud-resolving model forced by sounding network budgets over the Niamey region and over the northern Australian region. We have devoted some of the effort of this project to examining how well satellite data can determine the global breadth of the anvil cloud measurements obtained at the ARM ground sites. We next considered whether satellite data could be objectively analyzed to so that their large global measurement sets can be systematically related to the ARM measurements. Further differences were detailed between the land and ocean MCS anvil clouds by examining the interior structure of the anvils with the satellite-detected the CloudSat Cloud Profiling Radar (CPR). The satellite survey of anvil clouds in the Indo-Pacific region was continued to determine the role of MCSs in producing the cloud pattern associated with the MJO.
Kaspi, Yohai
2008-01-01
This thesis studies the dynamics of a rotating compressible gas sphere, driven by internal convection, as a model for the dynamics on the giant planets. We develop a new general circulation model for the Jovian atmosphere, ...
Continuous VRML output fromContinuous VRML output from regional circulation models: aregional and volume to viewview ·· Generate Virtual Reality Modeling LanguageGenerate Virtual Reality ModelingDesktop or laptop PC with web browser High speed/large RAM not essentialHigh speed/large RAM not essential
On the Wind Power Input to the Ocean General Circulation XIAOMING ZHAI
Wunsch, Carl
On the Wind Power Input to the Ocean General Circulation XIAOMING ZHAI Atmospheric, Oceanic January 2012, in final form 3 May 2012) ABSTRACT The wind power input to the ocean general circulation is usually calculated from the time-averaged wind products. Here, this wind power input is reexamined using
Lee, Jung-Eun; Johnson, Kathleen; Fung, Inez
2009-01-01
Modeling d 18 O in precipitation over the tropical Americas:2007), Millennial-scale precipitation changes in southernStable isotopes in precipitation, Tellus, 16, 436 – Fedorov,
Power-Law and Long-Memory Characteristics of the Atmospheric General Circulation DMITRY I. VYUSHIN memory'' or ``power-law'' model. Such a model fits a temporal spectrum to a single power-law function, which thereby accumulates more power at lower frequencies than an AR1 fit. In this study, several power
V. Ramaswamy; L. J. Donner; J-C. Golaz; S. A. Klein
2010-06-17
This report briefly summarizes the progress made by ARM postdoctoral fellow, Yanluan Lin, at GFDL during the period from October 2008 to present. Several ARM datasets have been used for GFDL model evaluation, understanding, and improvement. This includes a new ice fall speed parameterization with riming impact and its test in GFDL AM3, evaluation of model cloud and radiation diurnal and seasonal variation using ARM CMBE data, model ice water content evaluation using ARM cirrus data, and coordination of the TWPICE global model intercomparison. The work illustrates the potential and importance of ARM data for GCM evaluation, understanding, and ultimately, improvement of GCM cloud and radiation parameterizations. Future work includes evaluation and improvement of the new dynamicsPDF cloud scheme and aerosol activation in the GFDL model.
COMPUTATIONAL MODELING OF CIRCULATING FLUIDIZED BED REACTORS
Ibrahim, Essam A
2013-01-09
Details of numerical simulations of two-phase gas-solid turbulent flow in the riser section of Circulating Fluidized Bed Reactor (CFBR) using Computational Fluid Dynamics (CFD) technique are reported. Two CFBR riser configurations are considered and modeled. Each of these two riser models consist of inlet, exit, connecting elbows and a main pipe. Both riser configurations are cylindrical and have the same diameter but differ in their inlet lengths and main pipe height to enable investigation of riser geometrical scaling effects. In addition, two types of solid particles are exploited in the solid phase of the two-phase gas-solid riser flow simulations to study the influence of solid loading ratio on flow patterns. The gaseous phase in the two-phase flow is represented by standard atmospheric air. The CFD-based FLUENT software is employed to obtain steady state and transient solutions for flow modulations in the riser. The physical dimensions, types and numbers of computation meshes, and solution methodology utilized in the present work are stated. Flow parameters, such as static and dynamic pressure, species velocity, and volume fractions are monitored and analyzed. The differences in the computational results between the two models, under steady and transient conditions, are compared, contrasted, and discussed.
Testing Components of New Community Isopycnal Ocean Circulation Model
Bryan, Kirk
2008-05-09
The ocean and atmosphere are both governed by the same physical laws and models of the two media have many similarities. However, there are critical differences that call for special methods to provide the best simulation. One of the most important difference is that the ocean is nearly opaque to radiation in the visible and infra-red part of the spectrum. For this reason water mass properties in the ocean are conserved along trajectories for long distances and for long periods of time. For this reason isopycnal coordinate models would seem to have a distinct advantage in simulating ocean circulation. In such a model the coordinate surfaces are aligned with the natural paths of near adiabatic, density conserving flow in the main thermocline. The difficulty with this approach is at the upper and lower boundaries of the ocean, which in general do not coincide with density surfaces. For this reason hybrid coordinate models were proposed by Bleck and Boudra (1981) in which Cartesian coordinates were used near the ocean surface and isopycnal coordinates were used in the main thermocline. This feature is now part of the HICOM model (Bleck, 2002).
1950 B i M d l 1960 General Circulation
Rannacher, Rolf
AFA 2001 TAR 2000 Earth System Models (ESMs) 2014 ARS Climate Research Meteo- rology Climate Change Atmosphere Ocean Models (AOGCMs) 1979 Charney Report 1990 FAR 1995 SAR 2007 AFA 2001 TAR 2000 Earth System Models (ESMs) 2014 ARS Climate Research Meteo- rology Climate Change Science and Policy 1 Cl Re Meteo
The Mars thermosphere. 2. General circulation with coupled dynamics and composition
Bougher, S.W. (Univ. of Arizona, Tucson (USA)); Roble, R.G.; Ridley, E.C.; Dickinson, R.E. (National Center for Atmospheric Research, Boulder, CO (USA))
1990-08-30
The National Center for Atmospheric Research thermospheric general circulation model (TGCM) for the Earth's thermosphere has been modified to examine the three-dimensional structure and circulation of the upper mesosphere and thermosphere of Mars (MTGCM). The computational framework and major processes unique to a CO{sub 2} thermosphere are similar to those utilized in a recent Venus TGCM. Solar EUV, UV, and IR heating alone combine to drive the Martian winds above {approximately}100 km. An equinox version of the code is used to examine the Mars global dynamics and structure for two specific observational periods spanning a range of solar activity: Viking 1 (July 1976) and Mariner 6-7 (August-September 1969). The MTGCM is then modified to predict the state of the Mars thermosphere for various combinations of solar and orbital conditions. Calculations show that no nightside cryosphere of the type observed on Venus is obtained on the Mars nightside. Instead, planetary rotation significantly modifies the winds and the day-to-night contrast in densities and temperatures, giving a diurnal behavior similar to the Earth under quiet solar conditions. Maximum exospheric temperatures are calculated near 1,500 LT ({le} 305 K), with minimum values at 0500 LT ({le} 175 K). The global temperature distribution is strongly modified by nightside adiabatic heating (subsidence) and dayside cooling (upwelling). The global winds also affect vertical density distributions; vertical eddy diffusion much weaker than used in previous one-dimensional models is required to maintain observed Viking profiles. A solar cycle variation in dayside exospheric temperatures of {approximately}195-305 K is simulated by the Viking and Mariner runs.
Estimates of the Southern Ocean general circulation improved by animal-borne instruments
Wunsch, Carl
of the Southern Ocean have become available through the use of instrumented seals. ConductivityEstimates of the Southern Ocean general circulation improved by animal-borne instruments Fabien collection of seal-derived hydrographic data is now available, consisting of more than 165,000 profiles
Modeling the Circulation in Penobscot Bay, Maine Huijie Xue1
Xiu, Peng
Xue et al1 Modeling the Circulation in Penobscot Bay, Maine Huijie Xue1 , Yu Xu1 , David Brooks2 , Neal Pettigrew1 , John Wallinga1 1. School of Marine Sciences, University of Maine, Orono, ME 04469 Penobscot Bay, with approximate dimensions 50 x 100 km, is the largest estuarine embayment along the Maine
Modeling of a coal-fired natural circulation boiler
Bhambare, K.S.; Mitra, S.K.; Gaitonde, U.N.
2007-06-15
Modeling of a natural circulation boiler for a coal-fired thermal power station is presented here. The boiler system is divided into seven subcomponents, and for each section, models based on conservation of mass, momentum, and energy are formulated. The pressure drop at various sections and the heat transfer coefficients are computed using empirical correlations. Solutions are obtained by using SIMULINK. The model is validated by comparing its steady state and dynamic responses with the actual plant data. Open loop responses of the model to the step changes in the operating parameters, such as pressure, temperature, steam flow, feed water flow, are also analyzed. The present model can be used for the development and design of effective boiler control systems.
A regional numerical ocean model of the circulation in the Bay of Biscay
Drijfhout, Sybren
A regional numerical ocean model of the circulation in the Bay of Biscay Y. Friocourt,1,2,3 B Peninsula and in the Bay of Biscay is investigated by means of a regional ocean model. In particular numerical ocean model of the circulation in the Bay of Biscay, J. Geophys. Res., 112, C09008, doi:10
Lyapunov Exponents of a Simple Stochastic Model of the Thermally and Wind-Driven Ocean Circulation
Monahan, Adam Hugh
Lyapunov Exponents of a Simple Stochastic Model of the Thermally and Wind-Driven Ocean Circulation, then the leading Lyapunov exponent of the circulation can become positive for sufficiently strong fluctuations of the leading Lyapunov exponent can have a substantial effect on the predictability of the system. 1 #12
3D modeling of GJ1214b's atmosphere: vertical mixing driven by an anti-Hadley circulation
Charnay, Benjamin; Leconte, Jérémy
2015-01-01
GJ1214b is a warm sub-Neptune transiting in front of a nearby M dwarf star. Recent observations indicate the presence of high and thick clouds or haze whose presence requires strong atmospheric mixing. In order to understand the transport and distribution of such clouds/haze, we study the atmospheric circulation and the vertical mixing of GJ1214b with a 3D General Circulation Model for cloud-free hydrogen-dominated atmospheres (metallicity of 1, 10 and 100 times the solar value) and for a water-dominated atmosphere. We analyze the effect of the atmospheric metallicity on the thermal structure and zonal winds. We also analyze the zonal mean meridional circulation and show that it corresponds to an anti-Hadley circulation in most of the atmosphere with upwelling at mid-latitude and downwelling at the equator in average. This circulation must be present on a large range of synchronously rotating exoplanets with strong impact on cloud formation and distribution. Using simple tracers, we show that vertical winds o...
Predictive models of circulating fluidized bed combustors. 12th technical progress report
Gidaspow, D.
1992-07-01
Steady flows influenced by walls cannot be described by inviscid models. Flows in circulating fluidized beds have significant wall effects. Particles in the form of clusters or layers can be seen to run down the walls. Hence modeling of circulating fluidized beds (CFB) without a viscosity is not possible. However, in interpreting Equations (8-1) and (8-2) it must be kept in mind that CFB or most other two phase flows are never in a true steady state. Then the viscosity in Equations (8-1) and (8-2) may not be the true fluid viscosity to be discussed next, but an Eddy type viscosity caused by two phase flow oscillations usually referred to as turbulence. In view of the transient nature of two-phase flow, the drag and the boundary layer thickness may not be proportional to the square root of the intrinsic viscosity but depend upon it to a much smaller extent. As another example, liquid-solid flow and settling of colloidal particles in a lamella electrosettler the settling process is only moderately affected by viscosity. Inviscid flow with settling is a good first approximation to this electric field driven process. The physical meaning of the particulate phase viscosity is described in detail in the chapter on kinetic theory. Here the conventional derivation resented in single phase fluid mechanics is generalized to multiphase flow.
Posters A Stratiform Cloud Parameterization for General Circulation Models
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass mapSpeedingProgram Guidelines This document outlines the majorL.Posters Posters51
Posters Comparison Between General Circulation Model Simulation and Central Equatorial
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass mapSpeedingProgram Guidelines This document outlines the majorL.Posters
Posters Treatment of Cloud Radiative Effects in General Circulation Models
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass mapSpeedingProgram Guidelines This document outlines the majorL.Posters955 Posters3735
Evaluation of cirrus statistics produced by general circulation models
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submitKansasCommunitiesof Energy8) Wigner Home Â·the EffectEvaluation
NearCoM-TVD --A quasi-3D nearshore circulation and sediment transport model
Kirby, James T.
NearCoM-TVD -- A quasi-3D nearshore circulation and sediment transport model Jia-Lin Chen , Fengyan: Nearshore community model TVD-scheme Sediment transport Sandbar migration The newly developed nearshore). For sediment transport applications, two sediment transport models are applied to pre- dict three sandbar
Spiga, Aymeric
A new model to simulate the Martian mesoscale and microscale atmospheric circulation: Validation) Mesoscale Model is a new versatile simulator of the Martian atmosphere and environment at horizontal scales, and photochemistry cycles. Since LMD-GCM large-scale simulations are also used to drive the mesoscale model
structure in Lake Michigan: spring thermal bar, full stratification, deepening of the thermocline duringModeling circulation and thermal structure in Lake Michigan: Annual cycle and interannual and thermal structure in the lake. The model was able to reproduce all of the basic features of the thermal
An unsteady wave driver for narrowbanded waves: modeling nearshore circulation driven by wave groups
Kirby, James T.
An unsteady wave driver for narrowbanded waves: modeling nearshore circulation driven by wave Abstract In this paper, we derive an unsteady refractiondiffraction model for narrowbanded water waves for use in computing coupled wavecurrent motion in the nearshore. The end result is a variable
Modeling wind-driven circulation during the March 1998 sediment resuspension event in Lake Michigan
Modeling wind-driven circulation during the March 1998 sediment resuspension event in Lake Michigan Lake Michigan caused by a storm with winds up to 20 m/s. The hydrodynamic model is driven with surface winds derived from observed meteorological conditions at 18 land stations and a meteorological buoy
Model-free adaptive control of supercritical circulating fluidized-bed boilers
Cheng, George Shu-Xing; Mulkey, Steven L
2014-12-16
A novel 3-Input-3-Output (3.times.3) Fuel-Air Ratio Model-Free Adaptive (MFA) controller is introduced, which can effectively control key process variables including Bed Temperature, Excess O2, and Furnace Negative Pressure of combustion processes of advanced boilers. A novel 7-input-7-output (7.times.7) MFA control system is also described for controlling a combined 3-Input-3-Output (3.times.3) process of Boiler-Turbine-Generator (BTG) units and a 5.times.5 CFB combustion process of advanced boilers. Those boilers include Circulating Fluidized-Bed (CFB) Boilers and Once-Through Supercritical Circulating Fluidized-Bed (OTSC CFB) Boilers.
A Continuous ` \\Gamma oe Vertical Coordinate for a Baroclinic Model of the Atmospheric Circulation
Drake, John B.
meteorolgoical coordinate system is developed which can support a continuous isentropic oe vertical coordinate and boundary layer approximations were addressed by the introduction of a hybrid (patched) model [15]. By use analysis [14, 8]. The effects of heating on the circulation are most clearly seen with the isentropic
Follows, Mick
Evaluating carbon sequestration efficiency in an ocean circulation model by adjoint sensitivity the application of the adjoint method to develop three-dimensional maps of carbon sequestration efficiency. Sequestration efficiency (the percentage of carbon injected at a continuous point source that remains
Parameterization of gravity current entrainment for ocean circulation models using a high-order 3D
Ozgökmen, Tamay M.
Parameterization of gravity current entrainment for ocean circulation models using a high-order 3D on the work by Turner [Turner, J.S., 1986. The development of the entrainment assumption and its application. Weather Rev. 128, 14021419], an algebraic parameterization of the entrainment process in gravity current
DETECTING AND TRACKING OF MESOSCALE OCEANIC FEATURES IN THE MIAMI ISOPYCNIC CIRCULATION OCEAN MODEL
Tandon, Amit
DETECTING AND TRACKING OF MESOSCALE OCEANIC FEATURES IN THE MIAMI ISOPYCNIC CIRCULATION OCEAN MODEL developed to automatically detect, locate and track mesoscale eddies spatially and temporally. Using an invaluable tool to assess mesoscale oceanic features. Key Words Scientific Visualization, Eddy Detection
WORK IN PROGRESS --NOT FOR GENERAL CIRCULATION Animal Spirits: Affective and Deliberative
, and that the person's behavior is chosen to best achieve those goals. We develop a model in which a person's behavior model provides a framework for understanding many departures from full rationality discussed on factors that moderate the relative influence of the two systems, our model generates a variety of novel
Paris-Sud XI, Université de
Central South Pacific thermocline water circulation from a high-resolution ocean model validated. Introduction [2] Most South Pacific Ocean studies have been focused on its western or eastern part, leaving 12 January 2009; accepted 28 January 2009; published 13 May 2009. [1] The oceanic circulation
40 greater influence and penetration of deep water formed in 41 the Southern Ocean [e.g., Oppo2 Ocean circulation at the Last Glacial Maximum: 3 A combined modeling and magnetic proxy (NADW) is an important component of the ocean thermohaline 7 circulation, but debate exists over
MODELING STRATEGIES TO COMPUTE NATURAL CIRCULATION USING CFD IN A VHTR AFTER A LOFA
Yu-Hsin Tung; Richard W. Johnson; Ching-Chang Chieng; Yuh-Ming Ferng
2012-11-01
A prismatic gas-cooled very high temperature reactor (VHTR) is being developed under the next generation nuclear plant program (NGNP) of the U.S. Department of Energy, Office of Nuclear Energy. In the design of the prismatic VHTR, hexagonal shaped graphite blocks are drilled to allow insertion of fuel pins, made of compacted TRISO fuel particles, and coolant channels for the helium coolant. One of the concerns for the reactor design is the effects of a loss of flow accident (LOFA) where the coolant circulators are lost for some reason, causing a loss of forced coolant flow through the core. In such an event, it is desired to know what happens to the (reduced) heat still being generated in the core and if it represents a problem for the fuel compacts, the graphite core or the reactor vessel (RV) walls. One of the mechanisms for the transport of heat out of the core is by the natural circulation of the coolant, which is still present. That is, how much heat may be transported by natural circulation through the core and upwards to the top of the upper plenum? It is beyond current capability for a computational fluid dynamic (CFD) analysis to perform a calculation on the whole RV with a sufficiently refined mesh to examine the full potential of natural circulation in the vessel. The present paper reports the investigation of several strategies to model the flow and heat transfer in the RV. It is found that it is necessary to employ representative geometries of the core to estimate the heat transfer. However, by taking advantage of global and local symmetries, a detailed estimate of the strength of the resulting natural circulation and the level of heat transfer to the top of the upper plenum is obtained.
Study of natural circulation in a VHTR after a LOFA using different turbulence models
Yu-Hsin Tung; Yuh-Ming Ferng; Richard W. Johnson; Ching-Chang Chieng
2013-10-01
Natural convection currents in the core are anticipated in the event of the failure of the gas circulator in a prismatic gas-cooled very high temperature reactor (VHTR). The paths that the helium coolant takes in forming natural circulation loops and the effective heat transport are of interest. The heated flow in the reactor core is turbulent during normal operating conditions and at the beginning of the LOFA with forced convection, but the flow may significantly be slowed down after the event and laminarized with mixed convection. In the present study, the potential occurrence and effective heat transport of natural circulation are demonstrated using computational fluid dynamic (CFD) calculations with different turbulence models as well as laminar flow. Validations and recommendation on turbulence model selection are conducted. The study concludes that large loop natural convection is formed due to the enhanced turbulence levels by the buoyancy effect and the turbulent regime near the interface of upper plenum and flow channels increases the flow resistance for channel flows entering upper plenum and thus less heat can be removed from the core than the prediction by laminar flow assumption.
Ma, Po-Lun; Rasch, Philip J.; Wang, Hailong; Zhang, Kai; Easter, Richard C.; Tilmes, S.; Fast, Jerome D.; Liu, Xiaohong; Yoon, Jin-Ho; Lamarque, Jean-Francois
2013-05-28
Current climate models generally under-predict the surface concentration of black carbon (BC) in the Arctic due to the uncertainties associated with emissions, transport, and removal. This bias is also present in the Community Atmosphere Model Version 5.1 (CAM5). In this study, we investigate the uncertainty of Arctic BC due to transport processes simulated by CAM5 by configuring the model to run in an “offline mode” in which the large-scale circulations are prescribed. We compare the simulated BC transport when the offline model is driven by the meteorology predicted by the standard free-running CAM5 with simulations where the meteorology is constrained to agree with reanalysis products. Some circulation biases are apparent: the free-running CAM5 produces about 50% less transient eddy transport of BC than the reanalysis-driven simulations, which may be attributed to the coarse model resolution insufficient to represent eddies. Our analysis shows that the free-running CAM5 reasonably captures the essence of the Arctic Oscillation (AO), but some discernable differences in the spatial pattern of the AO between the free-running CAM5 and the reanalysis-driven simulations result in significantly different AO modulation of BC transport over Northeast Asia and Eastern Europe. Nevertheless, we find that the overall climatological circulation patterns simulated by the free-running CAM5 generally resembles those from the reanalysis products, and BC transport is very similar in both simulation sets. Therefore, the simulated circulation features regulating the long-range BC transport is unlikely the most important cause of the large under-prediction of surface BC concentration in the Arctic.
GENERAL CIRCULATION Energy Cycle
Grotjahn, Richard
process. PE is useful for global energy balance. Solar radiant energy does not reach the Earth equally static energy (DSE), while including the third defines moist static energy (MSE). Potential energy (PE) is usually defined as DSE. A tiny fraction of the PE, called the available potential energy, APE, can be used
Simple implementation of general dark energy models
Bloomfield, Jolyon K. [MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Ave #37241, Cambridge, MA, 02139 (United States); Pearson, Jonathan A., E-mail: jolyon@mit.edu, E-mail: jonathan.pearson@durham.ac.uk [Centre for Particle Theory, Department of Mathematical Sciences, Durham University, South Road, Durham, DH1 3LE (United Kingdom)
2014-03-01
We present a formalism for the numerical implementation of general theories of dark energy, combining the computational simplicity of the equation of state for perturbations approach with the generality of the effective field theory approach. An effective fluid description is employed, based on a general action describing single-scalar field models. The formalism is developed from first principles, and constructed keeping the goal of a simple implementation into CAMB in mind. Benefits of this approach include its straightforward implementation, the generality of the underlying theory, the fact that the evolved variables are physical quantities, and that model-independent phenomenological descriptions may be straightforwardly investigated. We hope this formulation will provide a powerful tool for the comparison of theoretical models of dark energy with observational data.
Santoso, Agus
Circumpolar Deep Water Circulation and Variability in a Coupled Climate Model AGUS SANTOSO Deep Water (CDW) is analyzed using a long-term integration of a coupled climate model. The variability into the Southern Ocean via North Atlantic Deep Water (NADW). Salinity dipole anomalies appear to propagate around
Newtonian Aspects of General Relativistic Galaxy Models
Aleksandar Rakic; Dominik J. Schwarz
2008-11-13
Many cosmological observations call for the existence of dark matter. The most direct evidence for dark matter is inferred from the measured flatness of galactic rotation curves. The latter is based on Newtonian gravity. Alternative approaches to the rotation curve problem by means of general relativity have recently been put forward. The class of models of interest is a subset of the axially symmetric and stationary solutions of Einstein's equations with rotating dust. As a step toward the understanding of general relativistic galaxy models, we analyse rigidly as well as non-rigidly rotating (Post-)Newtonian spacetimes. We find that the Newtonian limit of the considered general relativistic galaxy model leads to Post-Newtonian terms in the metric.
Modelling anisotropic fluid spheres in general relativity
Petarpa Boonserm; Tritos Ngampitipan; Matt Visser
2015-02-03
We argue that an arbitrary general relativistic anisotropic fluid sphere, (spherically symmetric but with transverse pressure not equal to radial pressure), can nevertheless be successfully modelled by suitable linear combinations of quite ordinary classical matter: an isotropic perfect fluid, a classical electromagnetic field, and a classical (minimally coupled) scalar field. While the most general decomposition is not unique, a preferred minimal decomposition can be constructed that is unique. We show how the classical energy conditions for the anisotropic fluid sphere can be related to energy conditions for the isotropic perfect fluid, electromagnetic field, and scalar field components of the model. Furthermore we show how this decomposition relates to the distribution of electric charge density and scalar charge density throughout the model that is used to mimic the anisotropic fluid sphere. Consequently, we can build physically reasonable matter models for almost any spherically symmetric spacetime.
Modelling anisotropic fluid spheres in general relativity
Boonserm, Petarpa; Visser, Matt
2015-01-01
We argue that an arbitrary general relativistic anisotropic fluid sphere, (spherically symmetric but with transverse pressure not equal to radial pressure), can nevertheless be successfully modelled by suitable linear combinations of quite ordinary classical matter: an isotropic perfect fluid, a classical electromagnetic field, and a classical (minimally coupled) scalar field. While the most general decomposition is not unique, a preferred minimal decomposition can be constructed that is unique. We show how the classical energy conditions for the anisotropic fluid sphere can be related to energy conditions for the isotropic perfect fluid, electromagnetic field, and scalar field components of the model. Furthermore we show how this decomposition relates to the distribution of electric charge density and scalar charge density throughout the model that is used to mimic the anisotropic fluid sphere. Consequently, we can build physically reasonable matter models for almost any spherically symmetric spacetime.
Abstract polymer models with general pair interactions
Aldo Procacci
2008-11-26
A convergence criterion of cluster expansion is presented in the case of an abstract polymer system with general pair interactions (i.e. not necessarily hard core or repulsive). As a concrete example, the low temperature disordered phase of the BEG model with infinite range interactions, decaying polynomially as $1/r^{d+\\lambda}$ with $\\lambda>0$, is studied.
Single-Column Modeling A Stratiform Cloud Parameterization for General Circulation Models
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effect Photovoltaics -7541 UnlimitedShiftwater vapor andParticle DatabaseC.J.A
Atlantic Ocean circulation at the last glacial maximum : inferences from data and models
Dail, Holly Janine
2012-01-01
This thesis focuses on ocean circulation and atmospheric forcing in the Atlantic Ocean at the Last Glacial Maximum (LGM, 18-21 thousand years before present). Relative to the pre-industrial climate, LGM atmospheric CO? ...
deYoung, Brad
. INDEX TERMS: 4219 Oceanography: General: Continental shelf processes; 4255 Oceanography: General: Numerical modeling; 4223 Oceanography: General: Descriptive and regional oceanography; 4263 Oceanography of the quasi-stationary, or mean, circu- lation is a common challenge in oceanography. Despite some formal
Mechanisms for Tropical Tropospheric Circulation Change in Response to Global Warming*
Xie, Shang-Ping
Mechanisms for Tropical Tropospheric Circulation Change in Response to Global Warming* JIAN MA change in global warming is studied by comparing the response of an atmospheric general circulation model globally in response to SST warming. A diagnostic framework is developed based on a linear baroclinic model
Interactions between the Indonesian Throughflow and circulations in the Indian and Pacific Oceans
Jensen, Tommy
Interactions between the Indonesian Throughflow and circulations in the Indian and Pacific Oceans with the Indonesian Throughflow (IT), particularly concerning subsurface currents in the Pacific Ocean, are studied model (LOM), both confined to the Indo-Pacific basin; and a global, ocean general circulation model
Seasonal Mean Circulation in the Yellow Sea A ModelGenerated Climatology
. Data in puts include seasonal hydrography, seasonal mean wind and river input, and oceanic tides pattern. The Changjiang discharge is driven offshore toward the Korean Strait by the summer wind. Results for winter and summer exhibit two distinct circulation modes. In winter, strong northerly wind
Vertical circulation and thermospheric composition: a modelling study H. Rishbeth1
Mueller-Wodarg, Ingo
-layer. At equinox, the vertical air motion is basically up by day, down by night, and the atomic oxygen is greater in winter than in summer, the semiannual anomaly exists if NmF2 is greater at equinox than by global-scale vertical and horizontal winds associated with a worldwide thermospheric circulation
Llamas Vidales, Jose Ricardo
2009-01-01
The liver regulates a myriad of vital functions including bile acid synthesis, hepatobiliary circulation, cholesterol homeostasis, drug metabolism, etc. This thesis focuses on the use of a 3D in vitro model of liver to ...
New model for nucleon generalized parton distributions
Radyushkin, Anatoly V.
2014-01-01
We describe a new type of models for nucleon generalized parton distributions (GPDs) H and E. They are heavily based on the fact nucleon GPDs require to use two forms of double distribution (DD) representations. The outcome of the new treatment is that the usual DD+D-term construction should be amended by an extra term, {xi} E{sub +}{sup 1} (x,{xi}) which has the DD structure {alpha}/{beta} e({beta},{alpha}, with e({beta},{alpha}) being the DD that generates GPD E(x,{xi}). We found that this function, unlike the D-term, has support in the whole -1 <= x <= 1 region. Furthermore, it does not vanish at the border points |x|={xi}.
Dynamical Reduction Models with General Gaussian Noises
Angelo Bassi; GianCarlo Ghirardi
2002-01-27
We consider the effect of replacing in stochastic differential equations leading to the dynamical collapse of the statevector, white noise stochastic processes with non white ones. We prove that such a modification can be consistently performed without altering the most interesting features of the previous models. One of the reasons to discuss this matter derives from the desire of being allowed to deal with physical stochastic fields, such as the gravitational one, which cannot give rise to white noises. From our point of view the most relevant motivation for the approach we propose here derives from the fact that in relativistic models the occurrence of white noises is the main responsible for the appearance of untractable divergences. Therefore, one can hope that resorting to non white noises one can overcome such a difficulty. We investigate stochastic equations with non white noises, we discuss their reduction properties and their physical implications. Our analysis has a precise interest not only for the above mentioned subject but also for the general study of dissipative systems and decoherence.
EXTENSIONS OF GENERALIZED LINEAR MODELING APPROACH TO STOCHASTIC WEATHER GENERATORS
Katz, Richard
weather) -- Software R open source statistical programming language: Function glm "Family;(2) Generalized Linear Models Statistical Framework -- Multiple Regression Analysis (Linear model or LM) Response
Discriminating robust and non-robust atmospheric circulation responses to global warming
Discriminating robust and non-robust atmospheric circulation responses to global warming Michael response to global warming in a set of atmospheric general circulation models (AGCMs) is investigated. The global-warmed climate is forced by a global pattern of warmed ocean surface temperatures
Extending Stochastic Resonance for Neuron Models to General Levy Noise
Applebaum, David
Extending Stochastic Resonance for Neuron Models to General Levy Noise David Applebaum, Probability resonance for general feedback continuous and spiking neuron models using additive Levy noise constrained extends to general Levy noise models. We achieve this by showing that "large jump" discontinuities
General single phase wellbore flow model
Ouyang, Liang-Biao; Arbabi, S.; Aziz, K.
1997-02-05
A general wellbore flow model, which incorporates not only frictional, accelerational and gravitational pressure drops, but also the pressure drop caused by inflow, is presented in this report. The new wellbore model is readily applicable to any wellbore perforation patterns and well completions, and can be easily incorporated in reservoir simulators or analytical reservoir inflow models. Three dimensionless numbers, the accelerational to frictional pressure gradient ratio R{sub af}, the gravitational to frictional pressure gradient ratio R{sub gf}, and the inflow-directional to accelerational pressure gradient ratio R{sub da}, have been introduced to quantitatively describe the relative importance of different pressure gradient components. For fluid flow in a production well, it is expected that there may exist up to three different regions of the wellbore: the laminar flow region, the partially-developed turbulent flow region, and the fully-developed turbulent flow region. The laminar flow region is located near the well toe, the partially-turbulent flow region lies in the middle of the wellbore, while the fully-developed turbulent flow region is at the downstream end or the heel of the wellbore. Length of each region depends on fluid properties, wellbore geometry and flow rate. As the distance from the well toe increases, flow rate in the wellbore increases and the ratios R{sub af} and R{sub da} decrease. Consequently accelerational and inflow-directional pressure drops have the greatest impact in the toe region of the wellbore. Near the well heel the local wellbore flow rate becomes large and close to the total well production rate, here R{sub af} and R{sub da} are small, therefore, both the accelerational and inflow-directional pressure drops can be neglected.
Lo, Min-Hui; Famiglietti, James S
2011-01-01
spatially variable water and energy balance processes, Waterdescribe fluxes of energy, water, and momentum between thewater vapor in the lower tropo- sphere increases moist static energy [
Interactive chemistry in the Laboratoire de Meteorologie Dynamique general circulation model
Hourdin, Chez Frédéric
of soluble species. The global and annual mean methane (7.9 years) and methylchloroform (4.6 years) chemical chemical scheme representative of the background chemistry of the troposphere is considered. We derive rapid interhemispheric exchange times of 1.13 1.38 years and 0.700.82 years, based on surface
Beltrami, Hugo
and compared to those obtained from subsurface geothermal data. Since GCMs have bottom boundary conditions. In addition, the agreement between the LSM surface fluxes and the borehole temperature reconstructed fluxes
Farrara, J. D.; Yu, J.-Y.
2002-01-01
surface solar fluxes decrease. In the Gulf of Mexico, thesolar radiative fluxes (not shown). For the Gulf of Mexico,
Farrara, J. D.; Yu, J.-Y.
2002-01-01
the recent notable Midwest summer flood ( drought) events ofdrought in particular—the rain- fall anomalies in the Midwest
Lo, Min-Hui; Famiglietti, James S
2011-01-01
LO AND FAMIGLIETTI: PRECIPITATION RESPONSE TO LAND PROCESSES2006), Regional tropical precipitation change mechanisms inrobustness of tropical precipitation asymmetry, J. Clim. ,
Modeling International Relationships in Applied General Equilibrium...
in Applied General Equilibrium (MIRAGE) AgencyCompany Organization: International Food Policy Research Institute, Centre d'Etudes Prospectives et d'Informations...
A Generalized Pyrolysis Model for Combustible Solids
Lautenberger, Chris
2007-01-01
development of the FDS5 pyrolysis model have helped shapebeta versions of the pyrolysis model, but never complained,pyrolysis. 153 Figure
Comparative Evaluation of Generalized River/Reservoir System Models
Wurbs, Ralph A.
2005-01-01
modeling systems that simulate the storage, flow, and diversion of water in a system of reservoirs and river reaches. Generalized means that a computer modeling system is designed for application to a range of concerns dealing with river basin systems...
Testing Generalized Linear Models Using Smoothing Spline Methods
Wang, Yuedong
Testing Generalized Linear Models Using Smoothing Spline Methods Anna Liu, Wendy Meiring and Yuedong Wang University of California, Santa Barbara Abstract This article considers testing exponential families. The tests developed are based on the connection between the smoothing spline models
A GENERAL EMPIRICALLY BASED MICROINSTABILITY TRANSPORT MODEL
Vlad, Gregorio
by turbulent processes. At present, no definitive transport model (i.e. a closed expression for energygyro-Bohm, shear dependent thermal diffusion coefficient to model the anomalous thermal transport in tokamaks processes generated by small scale, collisionless, electro- static microinstabilities (Romanelli, F., Zonca
Valerio Lucarini; Antonio Speranza; Renato VItolo
2005-11-24
A quasi-geostrophic intermediate complexity model is considered, providing a schematic representation of the baroclinic conversion processes which characterize the physics of the mid-latitudes atmospheric circulation. The model is relaxed towards a given latitudinal temperature profile, which acts as baroclinic forcing, controlled by a parameter TE determining the forced equator-to-pole temperature gradient. As TE increases, a transition takes place from a stationary regime to a periodic regime, and eventually to an earth-like chaotic regime where evolution takes place on a strange attractor. The dependence of the attractor dimension, metric entropy, and bounding box volume in phase space is studied by varying both TE and model resolution. The statistical properties of observables having physical relevance, namely the total energy of the system and the latitudinally averaged zonal wind, are also examined. It is emphasized that while the attractor's properties are quite sensitive to model resolution, the global physical observables depend less critically on it. For more detailed physical observables, such as the latitudinal profiles of the zonal wind, model resolution again may be critical: the effectiveness of the zonal wind convergence, acting as barotropic stabilization of the baroclinic waves, heavily relies on the details of the latitudinal structure of the fields. The necessity and complementarity of both the dynamical systems and physical approach is underlined.
Generalized matrix models and AGT correspondence at all genera
Giulio Bonelli; Kazunobu Maruyoshi; Alessandro Tanzini; Futoshi Yagi
2011-07-11
We study generalized matrix models corresponding to n-point Virasoro conformal blocks on Riemann surfaces with arbitrary genus g. Upon AGT correspondence, these describe four dimensional N=2 SU(2)^{n+3g-3} gauge theories with generalized quiver diagrams. We obtain the generalized matrix models from the perturbative evaluation of the Liouville correlation functions and verify the consistency of the description with respect to degenerations of the Riemann surface. Moreover, we derive the Seiberg-Witten curve for the N=2 gauge theory as the spectral curve of the generalized matrix model, thus providing a check of AGT correspondence at all genera.
Droidel: A General Approach to Android Framework Modeling Sam Blackshear
Chang, Bor-Yuh Evan
Droidel: A General Approach to Android Framework Modeling Sam Blackshear University of Colorado.chang@colorado.edu Abstract We present an approach and tool for general-purpose modeling of Android for static analysis. Our approach is to explicate the reflective bridge between the Android framework and an application to make
Zalucha, Angela M. (Angela Marie)
2010-01-01
Previous work with Mars General Circulation Models (MGCMs) has shown that the north-south slope in Martian topography causes asymmetries in the Hadley cells at equinox and in the annual average. To quantitatively solve for ...
Vangala, Prathyusha
2015-05-06
Modelling crash data has been an integral part of the research done in highway safety. Different tools have been suggested by researchers to analyze crash data. One such tool, which was recently proposed, is the Negative Binomial Generalized...
Generalized models and benchmarks for channel coordination
Toptal, Aysegul
2004-09-30
Models and Benchmarks for Channel Coordination. (August 2003) Ay¸ ¨ Toptal, B.S., Bilkent University, Turkey; M.S., Bilkent University, Turkey Chair of Advisory Committee: Dr. Sõla Cetinkaya This dissertation takes into account the latest industrial... of the Idea Behind Algorithm 3 . . . . . . . . . . . 58 12 Illustration of the Cost and Material Flows . . . . . . . . . . . . . 89 13 Illustration of Piv(Q) when (c -p)Pv > Rv . . . . . . . . . . . . . . 121 14 Different illustrations of Piv...
Orthogonal Forward Regression based on Directly Maximizing Model Generalization Capability
Chen, Sheng
for costly model evaluation. Index Terms -- orthogonal forward regression, structure identification, cross struc- ture construction process as a cost function in order to op- timize the model generalization introduces a construction algorithm for sparse kernel modelling using the leave-one-out test score also known
The Transition-Zone Water Filter Model for Global Material Circulation: Where Do We Stand?
with a small melt fraction, highly incompatible elements including hydro- gen, helium and argon are sequestered the fraction of water is small. Models have been developed to understand the structure of a melt layer Hilst, et al., 1997]), then the whole mantle is depleted with only a small volume (~10%) of relatively
Seiberg-Witten curve via generalized matrix model
Kazunobu Maruyoshi; Futoshi Yagi
2010-12-27
We study the generalized matrix model which corresponds to the n-point toric Virasoro conformal block. This describes four-dimensional N=2 SU(2)^n gauge theory with circular quiver diagram by the AGT relation. We first verify that it is obtained from the perturbative calculation of the Liouville correlation function. We derive the Seiberg-Witten curve for N=2 gauge theory as a spectral curve of the generalized matrix model.
Song, Guodong
Previous experimental studies to assess the contribution of blood-borne circulating (BBC) cells to cutaneous wound healing have relied on discontinuous pulsing of labeled BBC elements or bone marrow transplant protocols. ...
Paul, Ephraim Udo
2014-06-20
In-?depth knowledge of nearshore wave, circulation, and sediment processes are vital to effective and efficient management, operation, and regulation of ports and harbors. The scientific knowledge of these processes is currently lacking in Ibaka...
Bleck, R.
2004-05-19
The overall aim of this project was to continue development of a global version of the Miami Isopycnic Coordinate Ocean Model (MICOM) with the intent of turning it into a full-fledged oceanic component of an earth system model.
Generalization of neuron network model with delay feedback
Sanjeet Maisnam; R. K. Brojen Singh
2015-07-16
We present generalized delayed neural network (DNN) model with positive delay feedback and neuron history. The local stability analysis around trivial local equilibria of delayed neural networks has applied and determine the conditions for the existence of zero root. We develop few innovative delayed neural network models in different dimensions through transformation and extension of some existing models. We found that zero root can have multiplicity two under certain conditions. We further show how the characteristic equation can have zero root and its multiplicity is dependent on the conditions undertaken. Finally, we generalize the neural network of $N$ neurons through which we determine the general form of Jacobian of the linear form and corresponding characteristic equation of the system.
Modeling Smart Grid using Generalized Stochastic Petri Net
Dey, Amrita; Sanyal, Sugata
2011-01-01
Building smart grid for power system is a major challenge for safe, automated and energy efficient usage of electricity. The full implementation of the smart grid will evolve over time. However, before a new set of infrastructures are invested to build the smart grid, proper modeling and analysis is needed to avoid wastage of resources. Modeling also helps to identify and prioritize appropriate systems parameters. In this paper, an all comprehensive model of smart grid have been proposed using Generalized Stochastic Petri Nets (GSPN). The model is used to analyze the constraints and deliverables of the smart power grid of future.
A-model and generalized Chern-Simons theory
A. Schwarz
2005-01-30
The relation between open topological strings and Chern-Simons theory was discovered by E. Witten. He proved that A-model on T*M where M is a three-dimensional manifold is equivalent to Chern-Simons theory on M and that A-model on arbitrary Calabi-Yau 3-fold is related to Chern-Simons theory with instanton corrections. In present paper we discuss multidimensional generalization of these results.
General Network Lifetime and Cost Models for Evaluating Sensor Network
Heinzelman, Wendi
General Network Lifetime and Cost Models for Evaluating Sensor Network Deployment Strategies Zhao Cheng, Mark Perillo, and Wendi B. Heinzelman, Senior Member, IEEE Abstract--In multihop wireless sensor to energy imbalance among sensors often appear. Sensors closer to a data sink are usually required
Abstract polymer models with general pair interactions Aldo Procacci
Procacci, Aldo
Abstract polymer models with general pair interactions Aldo Procacci Dep. MatemÂ´atica-ICEx, UFMG (i.e. not necessarily hard core or repulsive). A concrete example is given in which polymers are r0 (possibly attractive), of the type 1/rd+ with > 0. 1. Introduction The abstract polymer gas is an important
A General Method for Feature Matching and Model Extraction
Olson, Clark F.
A General Method for Feature Matching and Model Extraction Clark F. Olson Jet Propulsion Laboratory is extracted from or #12;t to data that draws bene#12;ts from both generate-and-test methods and those based that are ecient and robust. We apply this method to object recognition, geometric primitive extraction, robust
GENERALIZED LINEAR MODELING APPROACH TO STOCHASTIC WEATHER GENERATORS
Katz, Richard
) Multisites (Spatial dependence of daily weather) -- Software R open source statistical programming language (Capable of "reproducing" any desired statistic) -- Disadvantages Synthetic weather looks too much like") Not amenable to uncertainty analysis #12;#12;#12;(2) Generalized Linear Models · Statistical Framework
Bayesian Comparison of Spatially Regularised General Linear Models
Penny, Will
Bayesian Comparison of Spatially Regularised General Linear Models Will Penny,1* Guillaume Flandin, London WC1N 3BG 2 Cuban Neuroscience Center, Havana, Cuba Abstract: In previous work (Penny et al., [2005. In neuroimaging, BMC is used in the analysis of func- tional integration [Penny et al., 2004]. This allows infer
A general holographic metal/superconductor phase transition model
Yan Peng; Yunqi Liu
2015-03-03
We study the scalar condensation of a general holographic superconductor model in AdS black hole background away from the probe limit. We find the model parameters together with the scalar mass and backreaction can determine the order of phase transitions completely. In addition, we observe two types of discontinuities of the scalar operator in the case of first order phase transitions. We analyze in detail the effects of the scalar mass and backreaction on the formation of discontinuities and arrive at an approximate relation between the threshold model parameters. Furthermore, we obtain superconductor solutions corresponding to higher energy states and examine the stability of these superconductor solutions.
A dark energy model alternative to generalized Chaplygin gas
Hova, Hoavo
2010-01-01
We propose a new fluid model of dark energy for $-1 \\leq \\omega_{\\text{eff}} \\leq 0$ as an alternative to the generalized Chaplygin gas models. The energy density of dark energy fluid is severely suppressed during barotropic matter dominant epochs, and it dominates the universe evolution only for eras of small redshift. From the perspective of fundamental physics, the fluid is a tachyon field with a scalar potential flatter than that of power-law decelerated expansion. Different from the standard $\\Lambda\\text{CDM}$ model, the suggested dark energy model claims that the cosmic acceleration at present epoch can not continue forever but will cease in the near future and a decelerated cosmic expansion will recover afterwards.
A dark energy model alternative to generalized Chaplygin gas
Hoavo Hova; Huanxiong Yang
2010-11-22
We propose a new fluid model of dark energy for $-1 \\leq \\omega_{\\text{eff}} \\leq 0$ as an alternative to the generalized Chaplygin gas models. The energy density of dark energy fluid is severely suppressed during barotropic matter dominant epochs, and it dominates the universe evolution only for eras of small redshift. From the perspective of fundamental physics, the fluid is a tachyon field with a scalar potential flatter than that of power-law decelerated expansion. Different from the standard $\\Lambda\\text{CDM}$ model, the suggested dark energy model claims that the cosmic acceleration at present epoch can not continue forever but will cease in the near future and a decelerated cosmic expansion will recover afterwards.
Exceptional and regular spectra of a generalized Rabi model
Michael Tomka; Omar El Araby; Mikhail Pletyukhov; Vladimir Gritsev
2014-12-05
We study the spectrum of the generalized Rabi model in which co- and counter-rotating terms have different coupling strengths. It is also equivalent to the model of a two-dimensional electron gas in a magnetic field with Rashba and Dresselhaus spin-orbit couplings. Like in case of the Rabi model, the spectrum of the generalized Rabi model consists of the regular and the exceptional parts. The latter is represented by the energy levels which cross at certain parameters' values which we determine explicitly. The wave functions of these exceptional states are given by finite order polynomials in the Bargmann representation. The roots of these polynomials satisfy a Bethe ansatz equation of the Gaudin type. At the exceptional points the model is therefore quasi-exactly solvable. An analytical approximation is derived for the regular part of the spectrum in the weak- and strong-coupling limits. In particular, in the strong-coupling limit the spectrum consists of two quasi-degenerate equidistant ladders.
Long-term effects of anthropogenic CO2 emissions simulated with a complex earth system model
Winguth, Arne
Long-term effects of anthropogenic CO2 emissions simulated with a complex earth system model Uwe earth system model con- sisting of an atmospheric general circulation model, an ocean general
Reshocks, rarefactions, and the generalized Layzer model for hydrodynamic instabilities
Mikaelian, K O
2008-06-10
We report numerical simulations and analytic modeling of shock tube experiments on Rayleigh-Taylor and Richtmyer-Meshkov instabilities. We examine single interfaces of the type A/B where the incident shock is initiated in A and the transmitted shock proceeds into B. Examples are He/air and air/He. In addition, we study finite-thickness or double-interface A/B/A configurations like air/SF{sub 6}/air gas-curtain experiments. We first consider conventional shock tubes that have a 'fixed' boundary: A solid endwall which reflects the transmitted shock and reshocks the interface(s). Then we focus on new experiments with a 'free' boundary--a membrane disrupted mechanically or by the transmitted shock, sending back a rarefaction towards the interface(s). Complex acceleration histories are achieved, relevant for Inertial Confinement Fusion implosions. We compare our simulation results with a generalized Layzer model for two fluids with time-dependent densities, and derive a new freeze-out condition whereby accelerating and compressive forces cancel each other out. Except for the recently reported failures of the Layzer model, the generalized Layzer model and hydrocode simulations for reshocks and rarefactions agree well with each other, and remain to be verified experimentally.
A General Approach to the Modelling of Trophic Chains
Rui Dilao; Tiago Domingos
1999-02-10
Based on the law of mass action (and its microscopic foundation) and mass conservation, we present here a method to derive consistent dynamic models for the time evolution of systems with an arbitrary number of species. Equations are derived through a mechanistic description, ensuring that all parameters have ecological meaning. After discussing the biological mechanisms associated to the logistic and Lotka-Volterra equations, we show how to derive general models for trophic chains, including the effects of internal states at fast time scales. We show that conformity with the mass action law leads to different functional forms for the Lotka-Volterra and trophic chain models. We use mass conservation to recover the concept of carrying capacity for an arbitrary food chain.
A general two-cycle network model of molecular motors
Yunxin Zhang
2009-04-24
Molecular motors are single macromolecules that generate forces at the piconewton range and nanometer scale. They convert chemical energy into mechanical work by moving along filamentous structures. In this paper, we study the velocity of two-head molecular motors in the framework of a mechanochemical network theory. The network model, a generalization of the recently work of Liepelt and Lipowsky (PRL 98, 258102 (2007)), is based on the discrete mechanochemical states of a molecular motor with multiple cycles. By generalizing the mathematical method developed by Fisher and Kolomeisky for single cycle motor (PNAS(2001) 98(14) P7748-7753), we are able to obtain an explicit formula for the velocity of a molecular motor.
Improved Indoor Tracking Based on Generalized t-Distribution Noise Model
Shuo, Liu; Le, Yin; Khuen, Ho Weng; Voon, Ling Keck
2015-01-01
t distribution noise model. Industrial & EngineeringGeneralized t -Distribution Noise Model Liu Shuo Yin Le Hogeneralized t-distribution noise model based on influence
Goodness-of-Fit Test Issues in Generalized Linear Mixed Models
Chen, Nai-Wei
2012-02-14
Linear mixed models and generalized linear mixed models are random-effects models widely applied to analyze clustered or hierarchical data. Generally, random effects are often assumed to be normally distributed in the ...
Dynamics of the Thermohaline Circulation under Wind forcing
Hongjun Gao; Jinqiao Duan
2001-08-12
The ocean thermohaline circulation, also called meridional overturning circulation, is caused by water density contrasts. This circulation has large capacity of carrying heat around the globe and it thus affects the energy budget and further affects the climate. We consider a thermohaline circulation model in the meridional plane under external wind forcing. We show that, when there is no wind forcing, the stream function and the density fluctuation (under appropriate metrics) tend to zero exponentially fast as time goes to infinity. With rapidly oscillating wind forcing, we obtain an averaging principle for the thermohaline circulation model. This averaging principle provides convergence results and comparison estimates between the original thermohaline circulation and the averaged thermohaline circulation, where the wind forcing is replaced by its time average. This establishes the validity for using the averaged thermohaline circulation model for numerical simulations at long time scales.
Electromagnetic Mass Models in General Theory of Relativity
Sumana Bhadra
2007-10-30
"Electromagnetic mass" where gravitational mass and other physical quantities originate from the electromagnetic field alone has a century long distinguished history. In the introductory chapter we have divided this history into three broad categories -- classical, quantum mechanical and general relativistic. Each of the categories has been described at a length to get the detailed picture of the physical background. Recent developments on Repulsive Electromagnetic Mass Models are of special interest in this introductory part of the thesis. In this context we have also stated motivation of our work. In the subsequent chapters we have presented our results and their physical significances. It is concluded that the electromagnetic mass models which are the sources of purely electromagnetic origin ``have not only heuristic flavor associated with the conjecture of Lorentz but even a physics having unconventional yet novel features characterizing their own contributions independent of the rest of the physics".
as they are actually a strong limitation in assimilation performance when assimilating any real data set. INDEX TERMS Caledonia, France Jacques Verron Laboratoire des Ecoulements Ge´ophysiques et Industriels, Centre National must be taken into proper account in conjunction with temperature and altimetric data. The sensitivity
2009-01-01
2009 P. E. Thornton et al. : Carbon-nitrogen interactionsregulate climate-carbon cycle feedbacks Monfray, P. ,T. H. : A global ocean carbon climatology: Results from
Global warming and changes in ocean circulation
Duffy, P.B.; Caldeira, K.C.
1998-02-01
This final report provides an overview of the goals and accomplishments of this project. Modeling and observational work has raised the possibility that global warming may cause changes in the circulation of the ocean. If such changes would occur they could have important climatic consequences. The first technical goal of this project was to investigate some of these possible changes in ocean circulation in a quantitative way, using a state-of -the-art numerical model of the ocean. Another goal was to develop our ocean model, a detailed three-dimensional numerical model of the ocean circulation and ocean carbon cycles. A major non-technical goal was to establish LLNL as a center of excellence in modelling the ocean circulation and carbon cycle.
Deep South China Sea circulation Guihua Wang,1,2
Xie, Shang-Ping
Deep South China Sea circulation Guihua Wang,1,2 ShangPing Xie,2,3 Tangdong Qu,2 and Rui Xin Huang4 Environment Model reveals a basin scale cyclonic circulation over the deep South China Sea (SCS). The cyclonic, and potential density in the deep SCS are consistent with the existence of the cyclonic circulation
Proton radioactivity within a generalized liquid drop model
J. M. Dong; H. F. Zhang; G. Royer
2009-06-02
The proton radioactivity half-lives of spherical proton emitters are investigated theoretically. The potential barriers preventing the emission of protons are determined in the quasimolecular shape path within a generalized liquid drop model (GLDM) including the proximity effects between nuclei in a neck and the mass and charge asymmetry. The penetrability is calculated with the WKB approximation. The spectroscopic factor has been taken into account in half-life calculation, which is obtained by employing the relativistic mean field (RMF) theory combined with the BCS method with the force NL3. The half-lives within the GLDM are compared with the experimental data and other theoretical values. The GLDM works quite well for spherical proton emitters when the spectroscopic factors are considered, indicating the necessity of introducing the spectroscopic factor and the success of the GLDM for proton emission. Finally, we present two formulas for proton emission half-life calculation similar to the Viola-Seaborg formulas and Royer's formulas of alpha decay.
Circulating Fluid Bed Combustor
Fraley, L. D.; Do, L. N.; Hsiao, K. H.
1982-01-01
The circulating bed combustor represents an alternative concept of burning coal in fluid bed technology, which offers distinct advantages over both the current conventional fluidized bed combustion system and the pulverized coal boilers equipped...
Generalized Min Cost Circulation Kevin Wayne
Wayne, Kevin
conversion, machine loading, fuel utilization, crop management, aircraft fleet assignment $40 £20$ £ = 1-cut theorem no integrality theorem Kevin Wayne 5 #12;Problem History Kantorovich '39 dual simplex Dantzig '62 network simplex Jewell '62 primal-dual Vaidya '89 interior point O (m1.5 n2 log B) time
Sharma, Abhishek
2015-05-04
Accurate prediction of wave environment is critical to the design of ports, harbors and coastal structures. In this dissertation, two advancements for existing phase-resolving models based on elliptic mild-slope equation (EMSE) are proposed. First...
Interacting generalized Chaplygin gas model in non-flat universe
M R Setare
2007-11-04
We employ the generalized Chaplygin gas of interacting dark energy to obtain the equation of state for the generalized Chaplygin gas energy density in non-flat universe. By choosing a negative value for $B$ we see that $w_{\\rm \\Lambda}^{eff}universe dominated by phantom dark energy.
PAC-Learning with General Class Noise Models Shahin Jabbari1
Holte, Robert
-dimension with the Empirical Risk Minimization (ERM) strategy. We introduce simple noise models for which classical ERM is not successful. Aiming at a more general- purpose algorithm for learning under noise, we generalize ERM to a more
Generalized charge-screening in relativistic Thomas–Fermi model
Akbari-Moghanjoughi, M.
2014-10-15
In this paper, we study the charge shielding within the relativistic Thomas-Fermi model for a wide range of electron number-densities and the atomic-number of screened ions. A generalized energy-density relation is obtained using the force-balance equation and taking into account the Chandrasekhar's relativistic electron degeneracy pressure. By numerically solving a second-order nonlinear differential equation, the Thomas-Fermi screening length is investigated, and the results are compared for three distinct regimes of the solid-density, warm-dense-matter, and white-dwarfs (WDs). It is revealed that our nonlinear screening theory is compatible with the exponentially decaying Thomas-Fermi-type shielding predicted by the linear response theory. Moreover, the variation of relative Thomas-Fermi screening length shows that extremely dense quantum electron fluids are relatively poor charge shielders. Calculation of the total number of screening electrons around a nucleus shows that there is a position of maximum number of screening localized electrons around the screened nucleus, which moves closer to the point-like nucleus by increase in the plasma number density but is unaffected due to increase in the atomic-number value. It is discovered that the total number of screening electrons, (N{sub s}?r{sub TF}{sup 3}/r{sub d}{sup 3} where r{sub TF} and r{sub d} are the Thomas-Fermi and interparticle distance, respectively) has a distinct limit for extremely dense plasmas such as WD-cores and neutron star crusts, which is unique for all given values of the atomic-number. This is equal to saying that in an ultrarelativistic degeneracy limit of electron-ion plasma, the screening length couples with the system dimensionality and the plasma becomes spherically self-similar. Current analysis can provide useful information on the effects of relativistic correction to the charge screening for a wide range of plasma density, such as the inertial-confined plasmas and compact stellar objects.
Modelling of the last 2ka Steven J. Phipps1
Phipps, Steven J.
of the past 2,000 years: Earth's orbital geometry is varied Atmospheric CO2, CH4 and N2O concentrations · Low-resolution General Circulation Models (GCMs) CSIRO Mk3L CCSM FOAM · IPCC-class models
van Hulten, Marco; Middag, Rob; de Baar, Hein; Gehlen, Marion; Dutay, Jean-Claude; Tagliabue, Alessandro
2014-01-01
The distribution of dissolved aluminium in the West Atlantic Ocean shows a mirror image with that of dissolved silicic acid, hinting at intricate interactions between the ocean cycling of Al and Si. The marine biogeochemistry of Al is of interest because of its potential impact on diatom opal remineralisation, hence Si availability. Furthermore, the dissolved Al concentration at the surface ocean has been used as a tracer for dust input, dust being the most important source of the bio-essential trace element iron to the ocean. Previously, the dissolved concentration of Al was simulated reasonably well with only a dust source, and scavenging by adsorption on settling biogenic debris as the only removal process. Here we explore the impacts of (i) a sediment source of Al in the Northern Hemisphere (especially north of ~40{\\deg}N), (ii) the imposed velocity field, and (iii) biological incorporation of Al on the modelled Al distribution in the ocean. The sediment source clearly improves the model results, and usin...
A Generalized Cohesive Zone Model of Peel Test for Pressure Sensitive Adhesives
Zhang, Liang
2010-01-16
itself. Generally, the failure of the adhesive is accompanied with a process of cavitation and fibrillation. Therefore, the cohesive zone is modeled as a continuous fibrillated region. A Maxwell model is employed to characterize the viscoelastic behavior...
The Transient Circulation Response to Radiative Forcings and Sea Surface Warming
Staten, Paul; Reichler, Thomas; Lu, Jian
2014-12-15
Tropospheric circulation shifts have strong potential to impact surface climate. But the magnitude of these shifts in a changing climate, and the attending regional hydrological changes, are difficult to project. Part of this difficulty arises from our lack of understanding of the physical mechanisms behind the circulation shifts themselves. In order to better delineate circulation shifts and their respective causes, we decompose the circulation response into (1) the "direct" response to radiative forcings themselves, and (2) the "indirect" response to changing sea surface temperatures. Using ensembles of 90-day climate model simulations with immediate switch-on forcings, including perturbed greenhouse gas concentrations, stratospheric ozone concentrations, and sea surface temperatures, we document the direct and indirect transient responses of the zonal mean general circulation, and investigate the roles of previously proposed mechanisms in shifting the midlatitude jet. We find that both the direct and indirect wind responses often begin in the lower stratosphere. Changes in midlatitude eddies are ubiquitous and synchronous with the midlatitude zonal wind response. Shifts in the critical latitude of wave absorption on either flank of the jet are not indicted as primary factors for the poleward shifting jet, although we see some evidence for increasing equatorward wave reflection over the southern hemisphere in response to sea surface warming. Mechanisms for the northern hemisphere jet shift are less clear.
Generalized Functional Linear Models Hans-Georg Muller (UC Davis) und U. Stadtmuller
Ulm, Universität
Generalized Functional Linear Models Hans-Georg M¨uller (UC Davis) und U. Stadtm¨uller Preprint FUNCTIONAL LINEAR MODELS Hans-Georg M¨uller1 and Ulrich Stadtm¨uller2 March 2004 1Department of Statistics. Wahrscheinlichkeitstheorie, Universit¨at Ulm, 89069 Ulm, Germany #12;ABSTRACT We propose a generalized functional linear
GENERALIZED FUNCTIONAL LINEAR MODELS Hans-Georg Muller1 and Ulrich Stadtmuller2
Müller, Hans-Georg
GENERALIZED FUNCTIONAL LINEAR MODELS Hans-Georg M¨uller1 and Ulrich Stadtm¨uller2 March 2004 1 a generalized functional linear regression model for a regression situation where the response variable is a scalar and the predictor is a random function. A linear predictor is obtained by forming the scalar
From residue matching patterns to protein folding topographies: General model and bovine
Berry, R. Stephen
From residue matching patterns to protein folding topographies: General model and bovine pancreatic-grained model for protein-folding dynamics is introduced based on a discretized representation of torsional, pattern recognition, and general characteristics of protein folding kinetics. Topology here implies
Learning Algorithms in a Decentralized General Equilibrium Model
Tesfatsion, Leigh
by lowering prices. This suggests that agent-based models with decentralized interaction risk untenable The growing body of ACE literature has addressed issues in finance (LeBaron 2000), labour markets (Tesfatsion
Shelf circulation patterns off Nigeria
Rider, Kelly Elizabeth
2005-08-29
Little has been published about the shelf circulation off the coast of Nigeria. Due to increased activity and associated incidents in the shallow waters offshore Nigeria, there is a need to more clearly define the near-shore circulation patterns...
Stochastic resonance in a generalized Von Foerster population growth model
Lumi, N.; Mankin, R.
2014-11-12
The stochastic dynamics of a population growth model, similar to the Von Foerster model for human population, is studied. The influence of fluctuating environment on the carrying capacity is modeled as a multiplicative dichotomous noise. It is established that an interplay between nonlinearity and environmental fluctuations can cause single unidirectional discontinuous transitions of the mean population size versus the noise amplitude, i.e., an increase of noise amplitude can induce a jump from a state with a moderate number of individuals to that with a very large number, while by decreasing the noise amplitude an opposite transition cannot be effected. An analytical expression of the mean escape time for such transitions is found. Particularly, it is shown that the mean transition time exhibits a strong minimum at intermediate values of noise correlation time, i.e., the phenomenon of stochastic resonance occurs. Applications of the results in ecology are also discussed.
Generalized Ginzburg-Landau models for non-conventional superconductors
S. Esposito; G. Salesi
2009-06-20
We review some recent extensions of the Ginzburg-Landau model able to describe several properties of non-conventional superconductors. In the first extension, s-wave superconductors endowed with two different critical temperatures are considered, their main thermodynamical and magnetic properties being calculated and discussed. Instead in the second extension we describe spin-triplet superconductivity (with a single critical temperature), studying in detail the main predicted physical properties. A thorough discussion of the peculiar predictions of our models and their physical consequences is as well performed.
A new eight vertex model and higher dimensional, multiparameter generalizations
B. Abdesselam; A. Chakrabarti
2008-02-12
We study statistical models, specifically transfer matrices corresponding to a multiparameter hierarchy of braid matrices of $(2n)^2\\times(2n)^2$ dimensions with $2n^2$ free parameters $(n=1,2,3,...)$. The simplest, $4\\times 4$ case is treated in detail. Powerful recursion relations are constructed giving the dependence on the spectral parameter $\\theta$ of the eigenvalues of the transfer matrix explicitly at each level of coproduct sequence. A brief study of higher dimensional cases ($n\\geq 2$) is presented pointing out features of particular interest. Spin chain Hamiltonians are also briefly presented for the hierarchy. In a long final section basic results are recapitulated with systematic analysis of their contents. Our eight vertex $4\\times 4$ case is compared to standard six vertex and eight vertex models.
System Advisor Model, SAM 2011.12.2: General Description
Gilman, P.; Dobos, A.
2012-02-01
This document describes the capabilities of the U.S. Department of Energy and National Renewable Energy Laboratory's System Advisor Model (SAM), Version 2011.12.2, released on December 2, 2011. SAM is software that models the cost and performance of renewable energy systems. Project developers, policy makers, equipment manufacturers, and researchers use graphs and tables of SAM results in the process of evaluating financial, technology, and incentive options for renewable energy projects. SAM simulates the performance of solar, wind, geothermal, biomass, and conventional power systems. The financial model can represent financing structures for projects that either buy and sell electricity at retail rates (residential and commercial) or sell electricity at a price determined in a power purchase agreement (utility). Advanced analysis options facilitate parametric, sensitivity, and statistical analyses, and allow for interfacing SAM with Microsoft Excel or with other computer programs. SAM is available as a free download at http://sam.nrel.gov. Technical support and more information about the software are available on the website.
System Advisor Model, SAM 2014.1.14: General Description
Blair, N.; Dobos, A. P.; Freeman, J.; Neises, T.; Wagner, M.; Ferguson, T.; Gilman, P.; Janzou, S.
2014-02-01
This document describes the capabilities of the U.S. Department of Energy and National Renewable Energy Laboratory's System Advisor Model (SAM), Version 2013.9.20, released on September 9, 2013. SAM is a computer model that calculates performance and financial metrics of renewable energy systems. Project developers, policy makers, equipment manufacturers, and researchers use graphs and tables of SAM results in the process of evaluating financial, technology, and incentive options for renewable energy projects. SAM simulates the performance of photovoltaic, concentrating solar power, solar water heating, wind, geothermal, biomass, and conventional power systems. The financial model can represent financial structures for projects that either buy and sell electricity at retail rates (residential and commercial) or sell electricity at a price determined in a power purchase agreement (utility). SAM's advanced simulation options facilitate parametric and sensitivity analyses, and statistical analysis capabilities are available for Monte Carlo simulation and weather variability (P50/P90) studies. SAM can also read input variables from Microsoft Excel worksheets. For software developers, the SAM software development kit (SDK) makes it possible to use SAM simulation modules in their applications written in C/C++, C#, Java, Python, and MATLAB. NREL provides both SAM and the SDK as free downloads at http://sam.nrel.gov. Technical support and more information about the software are available on the website.
Independent review of SCDAP/RELAP5 natural circulation calculations
Martinez, G.M.; Gross, R.J.; Martinez, M.J.; Rightley, G.S.
1994-01-01
A review and assessment of the uncertainties in the calculated response of reactor coolant system natural circulation using the SCDAP/RELAP5 computer code were completed. The SCDAP/RELAP5 calculation modeled a station blackout transient in the Surry nuclear power plant and concluded that primary system depressurization from natural circulation induced primary system failure is more likely than previously thought.
Generalized models as a universal approach to the analysis of nonlinear dynamical systems
Thilo Gross; Ulrike Feudel
2006-01-29
We present a universal approach to the investigation of the dynamics in generalized models. In these models the processes that are taken into account are not restricted to specific functional forms. Therefore a single generalized models can describe a class of systems which share a similar structure. Despite this generality, the proposed approach allows us to study the dynamical properties of generalized models efficiently in the framework of local bifurcation theory. The approach is based on a normalization procedure that is used to identify natural parameters of the system. The Jacobian in a steady state is then derived as a function of these parameters. The analytical computation of local bifurcations using computer algebra reveals conditions for the local asymptotic stability of steady states and provides certain insights on the global dynamics of the system. The proposed approach yields a close connection between modelling and nonlinear dynamics. We illustrate the investigation of generalized models by considering examples from three different disciplines of science: a socio-economic model of dynastic cycles in china, a model for a coupled laser system and a general ecological food web.
Unified Einstein-Virasoro Master Equation in the General Non-Linear Sigma Model
Boer, J. de; Halpern, M.B.
1996-06-05
The Virasoro master equation (VME) describes the general affine-Virasoro construction $T=L^abJ_aJ_b+iD^a \\dif J_a$ in the operator algebra of the WZW model, where $L^ab$ is the inverse inertia tensor and $D^a $ is the improvement vector. In this paper, we generalize this construction to find the general (one-loop) Virasoro construction in the operator algebra of the general non-linear sigma model. The result is a unified Einstein-Virasoro master equation which couples the spacetime spin-two field $L^ab$ to the background fields of the sigma model. For a particular solution $L_G^ab$, the unified system reduces to the canonical stress tensors and conventional Einstein equations of the sigma model, and the system reduces to the general affine-Virasoro construction and the VME when the sigma model is taken to be the WZW action. More generally, the unified system describes a space of conformal field theories which is presumably much larger than the sum of the general affine-Virasoro construction and the sigma model with its canonical stress tensors. We also discuss a number of algebraic and geometrical properties of the system, including its relation to an unsolved problem in the theory of $G$-structures on manifolds with torsion.
Mohri, Mehryar
applications or for adaptation purposes, one often needs to construct a language model based on the out put has been incorporated in a general software library for language modeling, the GRM Library, information extraction, machine translation, or document classification. In all cases, a language model
An integrated life cycle quality model for general public market software products
Suryn, Witold
An integrated life cycle quality model for general public market software products Witold Suryn1 of the software product results from its ultimate quality seen by both acquirers and end users. An integrated life cycle quality model, further called complement model for software product quality combines high level
THE BETA-JACOBI MATRIX MODEL, THE CS DECOMPOSITION, AND GENERALIZED SINGULAR
Sutton, Brian
THE BETA-JACOBI MATRIX MODEL, THE CS DECOMPOSITION, AND GENERALIZED SINGULAR VALUE PROBLEMS ALAN EDELMAN AND BRIAN D. SUTTON Abstract. We provide a solution to the -Jacobi matrix model problem posed the algorithm on a Haar-distributed random matrix to produce the -Jacobi matrix model. The Jacobi ensemble on Rn
Robust Bayesian general linear models W.D. Penny, J. Kilner, and F. Blankenburg
Penny, Will
Robust Bayesian general linear models W.D. Penny, J. Kilner, and F. Blankenburg Wellcome Department or cardiac noise sources (Penny et al., 2003). More recently, a number of approaches based on robust
Recurrence and non-ergodicity in generalized wind-tree models
Krzysztof Fr?czek; Pascal Hubert
2015-06-19
In this paper, we consider generalized wind-tree models and $\\Z^d$-covers over compact translation surfaces. Under suitable hypothesis, we prove recurrence of the linear flow in a generic direction and non-ergodicity of Lebesgue measure.
Generalized Poland-Scheraga denaturation model and two-dimensional renewal processes
Giambattista Giacomin; Maha Khatib
2015-10-27
The Poland-Scheraga model describes the denaturation transition of two complementary - in particular, equally long - strands of DNA, and it has enjoyed a remarkable success both for quantitative modeling purposes and at a more theoretical level. The solvable character of the homogeneous version of the model is one of features to which its success is due. In the bio-physical literature a generalization of the model, allowing different length and non complementarity of the strands, has been considered and the solvable character extends to this substantial generalization. We present a mathematical analysis of the homogeneous generalized Poland-Scheraga model. Our approach is based on the fact that such a model is a homogeneous pinning model based on a bivariate renewal process, much like the basic Poland-Scheraga model is a pinning model based on a univariate, i.e. standard, renewal. We present a complete analysis of the free energy singularities, which include the localization-delocalization critical point and (in general) other critical points that have been only partially captured in the physical literature. We obtain also precise estimates on the path properties of the model.
Constraining uncertainties in climate models using climate change detection techniques
Forest, Chris Eliot.; Allen, Myles R.; Stone, Peter H.; Sokolov, Andrei P.
Different atmosphere-ocean general circulation models produce significantly different projections of climate change in response to increases in greenhouse gases and aerosol concentrations in the atmosphere. The main reasons ...
Climate Determinism Revisited: Multiple Equilibria in a Complex Climate Model
Ferreira, David
Multiple equilibria in a coupled ocean–atmosphere–sea ice general circulation model (GCM) of an aquaplanet with many degrees of freedom are studied. Three different stable states are found for exactly the same set of ...
New self-dual $k$-generalized Abelian-Higgs models
Casana, R; Santos, A C
2015-01-01
We have shown the existence of self-dual solutions in new Maxwell-Higgs scenarios whose gauge field possess $k$-generalized dynamics, i.e., the kinetic part of the gauge action being highly nonlinear. We have implemented the BPS formalism providing highly nonlinear generalized self-dual equations whose solutions possess a total energy proportional to the magnetic flux. However, there is a key condition which allows to express the self-dual equations in a form mathematically similar those arising in the Maxwell-Higgs model. Under such a key condition, we have analyzed the general properties of the self-dual axially symmetric vortices. We have observed the generalization modifies the vortex core, the magnetic field amplitude and the bosonic masses but the total energy remains proportional to the quantized magnetic flux. Finally, we have established a prescription which allows to obtain different $k$-generalized Abelian Higgs models providing self-dual configurations.
AcceptedArticleThe effect of moist convection on thermally induced mesoscale circulations
Gentine, Pierre
AcceptedArticleThe effect of moist convection on thermally induced mesoscale circulations Malte of thermally induced mesoscale circulations rests primarily on observations and model studies of dry convection-eddy simulations are used to investigate the effect of moist convection on an idealized mesoscale circulation
OLAF ---A General Modeling System to Evaluate and Optimize the Location of an Air
Fliege, Jörg
OLAF --- A General Modeling System to Evaluate and Optimize the Location of an Air Polluting.2 The Air Dispersion Model . . . . . . . . . . . . . . . . . . . . . 14 3 Ecology and Chemokinetics 17 3 . . . . . . . . . . . . . . . . . . . . . . . 48 6.1.3 Meteorological Data . . . . . . . . . . . . . . . . . . . . 48 6.1.4 Pollutant Data
Modeling benzene plume elongation mechanisms exerted by ethanol using RT3D with a general
Alvarez, Pedro J.
Modeling benzene plume elongation mechanisms exerted by ethanol using RT3D with a general substrate ethanol on benzene fate and transport in fuel-contaminated groundwater and to discern the most influential benzene plume elongation mechanisms. The model, developed as a module for the Reactive Transport in 3
GENERAL TECHNICAL REPORT PSW-GTR-245 Fuel Load Modeling From Mensuration
of this study was to model a dead fuel load based on forest mensuration attributes from forest management from management programs are an efficient and low-cost alternative for estimating forest fuel loadsGENERAL TECHNICAL REPORT PSW-GTR-245 274 Fuel Load Modeling From Mensuration Attributes
A GENERALIZED MODEL OF MUTATION-SELECTION BALANCE WITH APPLICATIONS TO AGING
Evans, Steven N.
A GENERALIZED MODEL OF MUTATION-SELECTION BALANCE WITH APPLICATIONS TO AGING DAVID STEINSALTZ to cover mutation-driven changes in full age-specific demo- graphic schedules. The model accommodates of solutions in a restricted case. Examples are given of applications to the biodemography of aging. 1
The biogeochemistry and residual mean circulation of the southern ocean
Ito, Takamitsu, 1976-
2005-01-01
I develop conceptual models of the biogeochemistry and physical circulation of the Southern Ocean in order to study the air-sea fluxes of trace gases and biological productivity and their potential changes over ...
Geometry and General Relativity in the Groupoid Model with a Finite Structure Group
M. Heller; T. Miller; L. Pysiak; W. Sasin
2015-01-08
In a series of papers we proposed a model unifying general relativity and quantum mechanics. The idea was to deduce both general relativity and quantum mechanics from a noncommutative algebra ${\\cal A}_{\\Gamma}$ defined on a transformation groupoid $\\Gamma$ determined by the action of the Lorentz group on the frame bundle $(E, \\pi_M, M)$ over space-time $M$. In the present work, we construct a simplified version of the gravitational sector of this model in which the Lorentz group is replaced by a finite group $G$ and the frame bundle is trivial $E=M\\times G$. The model is fully computable. We define the Einstein-Hilbert action, with the help of which we derive the generalized vacuum Einstein equations. When the equations are projected to space-time (giving the "general relativistic limit"), the extra terms that appear due to our generalization can be interpreted as "matter terms", as in Kaluza-Klein-type models. To illustrate this effect we further simplify the metric matrix to a block diagonal form, compute for it the generalized Einstein equations and find two of their "Friedmann-like" solutions for the special case when $G =\\mathbb{Z}_2$. One of them gives the flat Minkowski space-time (which, however, is not static), another, a hyperbolic, linearly expanding universe.
Thermohaline Circulation Lynne D Talley
Talley, Lynne D.
currents. The convective source regions and ocean basins are connected through deep western boundary cur of the upper 2000 m of the ocean are about 10 times faster, reaching 1 m s 1 in bound- ary currents and about 0, Ltd, Chichester, 2002 #12;Thermohaline Circulation Thermohaline circulation is the part of the ocean
M. R. Setare
2007-01-26
In the present paper we consider the interacting holographic model of dark energy to investigate the validity of the generalized second laws of thermodynamics in non-flat (closed) universe enclosed by the event horizon measured from the sphere of the horizon named $L$. We show that for $L$ as the system's IR cut-off the generalized second law is respected for the special range of the deceleration parameter.
Exclusive $B \\to PV $ Decays and CP Violation in the General two-Higgs-doublet Model
Wu, Y L; 10.1103/PhysRevD.75.115006
2008-01-01
We calculate all the branching ratios and direct CP violations of $B \\to PV$ decays in a most general two-Higgs-doublet model with spontaneous CP violation. As the model has rich CP-violating sources, it is shown that the new physics effects to direct CP violations and branching ratios in some channels can be significant when adopting the generalized factorization approach to evaluate the hadronic matrix elements, which provides good signals for probing new physics beyond the SM in the future B experiments.
Exclusive $B \\to PV $ Decays and CP Violation in the General two-Higgs-doublet Model
Y. L. Wu; C. Zhuang
2007-01-10
We calculate all the branching ratios and direct CP violations of $B \\to PV$ decays in a most general two-Higgs-doublet model with spontaneous CP violation. As the model has rich CP-violating sources, it is shown that the new physics effects to direct CP violations and branching ratios in some channels can be significant when adopting the generalized factorization approach to evaluate the hadronic matrix elements, which provides good signals for probing new physics beyond the SM in the future B experiments.
A General Nonlinear Fluid Model for Reacting Plasma-Neutral Mixtures
Meier, E T; Shumlak, U
2012-04-06
A generalized, computationally tractable fluid model for capturing the effects of neutral particles in plasmas is derived. The model derivation begins with Boltzmann equations for singly charged ions, electrons, and a single neutral species. Electron-impact ionization, radiative recombination, and resonant charge exchange reactions are included. Moments of the reaction collision terms are detailed. Moments of the Boltzmann equations for electron, ion, and neutral species are combined to yield a two-component plasma-neutral fluid model. Separate density, momentum, and energy equations, each including reaction transfer terms, are produced for the plasma and neutral equations. The required closures for the plasma-neutral model are discussed.
Phase synchronization of coupled bursting neurons and the generalized Kuramoto model
Fabiano A. S. Ferrari; Ricardo L. Viana; Sérgio R. Lopes; Ruedi Stoop
2015-02-13
Bursting neurons fire rapid sequences of action potential spikes followed by a quiescent period. The basic dynamical mechanism of bursting is the slow currents that modulate a fast spiking activity caused by rapid ionic currents. Minimal models of bursting neurons must include both effects. We considered one of these models and its relation with a generalized Kuramoto model, thanks to the definition of a geometrical phase for bursting and a corresponding frequency. We considered neuronal networks with different connection topologies and investigated the transition from a non-synchronized to a partially phase-synchronized state as the coupling strength is varied. The numerically determined critical coupling strength value for this transition to occur is compared with theoretical results valid for the generalized Kuramoto model.
Tailleux, Remi
Identifying and quantifying nonconservative energy production/destruction terms in hydrostatic that physical inconsistencies between thermodynamics and dynamics usually introduce nonconservative production/destruction terms in the local total energy balance equation in numerical ocean general circulation models (OGCMs
Proton radioactivity within a generalized liquid drop model J. M. Dong,1
Paris-Sud XI, UniversitÃ© de
Proton radioactivity within a generalized liquid drop model J. M. Dong,1 H. F. Zhang,1 and G. Royer) The proton radioactivity half-lives of spherical proton emitters are investigated theoretically. The potential barriers preventing the emission of proton are determined in the quasimolecular shape path within
A generalized kinetic model for the formation and growth of single-walled metal oxide nanotubes
Nair, Sankar
A generalized kinetic model for the formation and growth of single-walled metal oxide nanotubes G,n a School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA b School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA c
Tighter Relaxations for Higher-Order Models based on Generalized Roof Duality
Lunds Universitet
Tighter Relaxations for Higher-Order Models based on Generalized Roof Duality Johan Fredriksson one of the most successful approaches, namely roof duality, for approximately solving such problems cone. In the sec- ond method, it is shown that the roof dual bound can be applied in an iterated way
Towards a Generalized Regression Model for On-body Energy Prediction from Treadmill Walking
Sukhatme, Gaurav S.
Towards a Generalized Regression Model for On-body Energy Prediction from Treadmill Walking sensor data to energy expenditure is the ques- tion of normalizating across physiological parameters. Common approaches such as weight scaling require validation for each new population. An alternative
Jia, Yan-Bin
IEEE TRANSACTIONS ON ROBOTICS, VOL. 26, NO. 5, OCTOBER 2010 837 Modeling Deformations of General Parametric Shells Grasped by a Robot Hand Jiang Tian and Yan-Bin Jia, Member, IEEE Abstract--The robot hand and normal of the contact area. Design and analysis of a manipulation strategy thus depend on reliable
Capacity Planning in a General Supply Chain with Multiple Contract Types Single Period Model
Graves, Stephen C.
and sufficient capacity to meet market demands. However, capacity planning is a very challenging task for manyCapacity Planning in a General Supply Chain with Multiple Contract Types Single Period Model Xin Huang · Stephen C. Graves Department of Electrical Engineering and Computer Science, Massachusetts
Change of variables as a method to study general ?-models: Bulk universality
Shcherbina, M.
2014-04-15
We consider ? matrix models with real analytic potentials. Assuming that the corresponding equilibrium density ? has a one-interval support (without loss of generality ? = [?2, 2]), we study the transformation of the correlation functions after the change of variables ?{sub i} ? ?(?{sub i}) with ?(?) chosen from the equation ?{sup ?}(?)?(?(?)) = ?{sub sc}(?), where ?{sub sc}(?) is the standard semicircle density. This gives us the “deformed” ?-model which has an additional “interaction” term. Standard transformation with the Gaussian integral allows us to show that the “deformed” ?-model may be reduced to the standard Gaussian ?-model with a small perturbation n{sup ?1}h(?). This reduces most of the problems of local and global regimes for ?-models to the corresponding problems for the Gaussian ?-model with a small perturbation. In the present paper, we prove the bulk universality of local eigenvalue statistics for both one-cut and multi-cut cases.
Well-posedness and generalized plane waves simulations of a 2D mode conversion model
Imbert-Gérard, Lise-Marie
2015-01-01
Certain types of electro-magnetic waves propagating in a plasma can undergo a mode conversion process. In magnetic confinement fusion, this phenomenon is very useful to heat the plasma, since it permits to transfer the heat at or near the plasma center. This work focuses on a mathematical model of wave propagation around the mode conversion region, from both theoretical and numerical points of view. It aims at developing, for a well-posed equation, specific basis functions to study a wave mode conversion process. These basis functions, called generalized plane waves, are intrinsically based on variable coefficients. As such, they are particularly adapted to the mode conversion problem. The design of generalized plane waves for the proposed model is described in detail. Their implementation within a discontinuous Galerkin method then provides numerical simulations of the process. These first 2D simulations for this model agree with qualitative aspects studied in previous works.
Well-posedness and generalized plane waves simulations of a 2D mode conversion model
Lise-Marie Imbert-Gérard
2015-04-27
Certain types of electro-magnetic waves propagating in a plasma can undergo a mode conversion process. In magnetic confinement fusion, this phenomenon is very useful to heat the plasma, since it permits to transfer the heat at or near the plasma center. This work focuses on a mathematical model of wave propagation around the mode conversion region, from both theoretical and numerical points of view. It aims at developing, for a well-posed equation, specific basis functions to study a wave mode conversion process. These basis functions, called generalized plane waves, are intrinsically based on variable coefficients. As such, they are particularly adapted to the mode conversion problem. The design of generalized plane waves for the proposed model is described in detail. Their implementation within a discontinuous Galerkin method then provides numerical simulations of the process. These first 2D simulations for this model agree with qualitative aspects studied in previous works.
Liou, K. N.
On the correlation between ice water content and ice crystal size and its application to radiative analysis involving ice water content (IWC) and mean effective ice crystal size (De) intended, K. N., Y. Gu, Q. Yue, and G. McFarguhar (2008), On the correlation between ice water content and ice
Barnett, T.P.
1998-11-30
The objectives of this report are to determine the structure of oceanic natural variability at time scales of decades to centuries, characterize the physical mechanisms responsible for the variability; determine the relative importance of heat, fresh water, and moment fluxes on the variability; determine the predictability of the variability on these times scales. (B204)
Subin, Z.M.
2013-01-01
in the Community Earth System Model 1 (CESM1) By ZACHARY M.into the Community Earth System Model 1 (CESM1) to study thearea. In the Community Earth System Model 1 (CESM1; http://
N. Itagaki; H. Matsuno; T. Suhara
2015-07-09
The antisymmetrized quasi-cluster model (AQCM) is a method to describe a transition from the alpha-cluster wave function to the jj-coupling shell model wave function. In this model, the cluster-shell transition is characterized by only two parameters; R representing the distance between alpha clusters and Lambda describing the breaking of alpha clusters, and the contribution of the spin-orbit interaction, very important in the jj-coupling shell model, can be taken into account starting with the alpha cluster model wave function. In this article we show the generality of AQCM by extending the application to heavier region; various 4N nuclei from 4He to 52Fe. We show and compare the energy curves for the alpha+40Ca cluster configuration calculated with and without alpha breaking effect in 44Ti.
Agarwala, R. [National Institutes of Health, Bethesda, MD (United States); Batzoglou, S. [MIT, Cambridge, MA (United States); Dancik, V. [Univ. of Southern California, Los Angeles, CA (United States)] [and others
1997-06-01
We consider the problem of determining the three-dimensional folding of a protein given its one-dimensional amino acid sequence. We use the HP model for protein folding proposed by Dill, which models protein as a chain of amino acid residues that are either hydrophobic or polar, and hydrophobic interactions are the dominant initial driving force for the protein folding. Hart and Istrail gave approximation algorithms for folding proteins on the cubic lattice under HP model. In this paper, we examine the choice of a lattice by considering its algorithmic and geometric implications and argue that triangular lattice is a more reasonable choice. We present a set of folding rules for a triangular lattice and analyze the approximation ratio which they achieve. In addition, we introduce a generalization of the HP model to account for residues having different levels of hydrophobicity. After describing the biological foundation for this generalization, we show that in the new model we are able to achieve similar constant factor approximation guarantees on the triangular lattice as were achieved in the standard HP model. While the structures derived from our folding rules are probably still far from biological reality, we hope that having a set of folding rules with different properties will yield more interesting folds when combined.
A General Hippocampal Computational Model Combining Episodic and Spatial Memory in a Spiking Model
Aguiar, Paulo de Castro
The hippocampus, in humans and rats, plays crucial roles in spatial tasks and nonspatial tasks involving episodic-type memory. This thesis presents a novel computational model of the hippocampus (CA1, CA3 and dentate ...
Zwickl, Derrick J.; Holder, Mark T.
2004-01-01
.— Bayesian phylo^enetic methods reiiuire Ihe selection of prior probability distribulions for all parameters of the model of evolution. These distribulii>ns allow one to incorporate prior information into a liayesian analysis, but even in the absence...
Energy-Momentum of the Friedmann Models in General Relativity and Teleparallel Theory of Gravity
M. Sharif; M. Jamil Amir
2008-09-09
This paper is devoted to the evaluation of the energy-momentum density components for the Friedmann models. For this purpose, we have used M${\\o}$ller's pseudotensor prescription in General Relativity and a certain energy-momentum density developed from his teleparallel formulation. It is shown that the energy density of the closed Friedmann universe vanishes on the spherical shell at the radius $\\rho=2\\sqrt{3}$. This coincides with the earlier results available in the literature. We also discuss the energy of the flat and open models. A comparison shows a partial consistency between the M${\\o}$ller's pseudotensor for General Relativity and teleparallel theory. Further, it is shown that the results are independent of the free dimensionless coupling constant of the teleparallel gravity.
Fourier analysis for generalized cylinders with polar models of cross-sections
Forsythe, William Clarence
1990-01-01
. Background 1. 2. Modeling Criteria 1. 3. Modeling Methods 1. 3. 1. Voxel Methods 1. 3. 2. Constructive Solid Geometry 1. 3. 3. Boundary Representation 1. 3. 4. Superquadrics 1. 4. Generalized Cylinder 1. 4. 1. GC Definition 1. 4. 2. GC Research 1. 4. 3. GC... such as spheres, cuboids, and tetrahedrons. This method works well with man-made objects. For instance, a table may be represented with five cuboids, using one cuboid for the top of the table, and one cuboid each, positioned appropriately, for the four legs...
Nonlinear dynamics of system oscillations modeled by a forced Van der Pol generalized oscillator
L. A. Hinvi; C. H. Miwadinou; A. V. Monwanou; J. B. Chabi Orou
2014-02-18
This paper considers the oscillations modeled by a forced Van der Pol generalized oscillator. These oscillations are described by a nonlinear differential equation of the form $ \\ddot{x}+x-\\varepsilon\\left(1-ax^2-b\\dot{x}^2\\right)\\dot{x}=E\\sin{{\\Omega}t}.$ The amplitudes of the forced harmonic, primary resonance superharmonic and subharmonic oscillatory states are obtained using the harmonic balance technique and the multiple time scales methods. We obtain also the hysteresis and jump phenomena in the system oscillations. Bifurcation sequences displayed by the model for each type of oscillatory states are performed numerically through the fourth-order Runge- Kutta scheme.
Allu, Srikanth; Velamur Asokan, Badri; Shelton, William A; Philip, Bobby; Pannala, Sreekanth
2014-01-01
A generalized three dimensional computational model based on unied formulation of electrode- electrolyte-electrode system of a electric double layer supercapacitor has been developed. The model accounts for charge transport across the solid-liquid system. This formulation based on volume averaging process is a widely used concept for the multiphase ow equations ([28] [36]) and is analogous to porous media theory typically employed for electrochemical systems [22] [39] [12]. This formulation is extended to the electrochemical equations for a supercapacitor in a consistent fashion, which allows for a single-domain approach with no need for explicit interfacial boundary conditions as previously employed ([38]). In this model it is easy to introduce the spatio-temporal variations, anisotropies of physical properties and it is also conducive for introducing any upscaled parameters from lower length{scale simulations and experiments. Due to the irregular geometric congurations including porous electrode, the charge transport and subsequent performance characteristics of the super-capacitor can be easily captured in higher dimensions. A generalized model of this nature also provides insight into the applicability of 1D models ([38]) and where multidimensional eects need to be considered. In addition, simple sensitivity analysis on key input parameters is performed in order to ascertain the dependence of the charge and discharge processes on these parameters. Finally, we demonstarted how this new formulation can be applied to non-planar supercapacitors
Minimum Description Length Model Selection Criteria for Generalized Linear Models Mark Hansen
Yu, Bin
of simulations for logistic regression illustrate that mixture MDL can ``bridge'' AIC and BIC in the sense. By viewing statistical modeling as a means of generating descriptions of observed data, the MDL framework (cf for a probability distribution Q on A. An integervalued function L corresponds to the code length of a binary
Nagurney, Anna
A General Multitiered Supply Chain Network Model of Quality Competition with Suppliers Dong Li1 a general multitiered supply chain network equilibrium model consisting of competing suppliers and competing, along with sensi- tivity analysis in which the impacts of capacity disruptions and complete supplier
Polvani, Lorenzo M.
[1] The effect of ozone depletion on temperature trends in the tropical lower stratosphere is explored with an atmospheric general circulation model, and directly contrasted to the effect of increased greenhouse gases and ...
Generalized Uncertainty Relations and Long Time Limits for Quantum Brownian Motion Models
C. Anastopoulos; J. J. Halliwell
1994-07-27
We study the time evolution of the reduced Wigner function for a class of quantum Brownian motion models. We derive two generalized uncertainty relations. The first consists of a sharp lower bound on the uncertainty function, $U = (\\Delta p)^2 (\\Delta q)^2 $, after evolution for time $t$ in the presence of an environment. The second, a stronger and simpler result, consists of a lower bound at time $t$ on a modified uncertainty function, essentially the area enclosed by the $1-\\sigma$ contour of the Wigner function. In both cases the minimizing initial state is a non-minimal Gaussian pure state. These generalized uncertainty relations supply a measure of the comparative size of quantum and thermal fluctuations. We prove two simple inequalites, relating uncertainty to von Neumann entropy, and the von Neumann entropy to linear entropy. We also prove some results on the long-time limit of the Wigner function for arbitrary initial states. For the harmonic oscillator the Wigner function for all initial states becomes a Gaussian at large times (often, but not always, a thermal state). We derive the explicit forms of the long-time limit for the free particle (which does not in general go to a Gaussian), and also for more general potentials in the approximation of high temperature.
Generalized Second Law of Thermodynamics for Non-canonical Scalar Field Model with Corrected-Entropy
Das, Sudipta; Mamon, Abdulla Al
2015-01-01
In this work, we have considered a non-canonical scalar field dark energy model in the framework of flat FRW background. It has also been assumed that the dark matter sector interacts with the non-canonical dark energy sector through some interaction term. Using the solutions for this interacting non-canonical scalar field dark energy model, we have investigated the validity of generalized second law (GSL) of thermodynamics in various scenarios using first law and area law of thermodynamics. For this purpose, we have assumed two types of horizons viz apparent horizon and event horizon for the universe and using first law of thermodynamics, we have examined the validity of GSL on both apparent and event horizons. Next, we have considered two types of entropy-corrections on apparent and event horizons. Using the modified area law, we have examined the validity of GSL of thermodynamics on apparent and event horizons under some restrictions of model parameters.
General model selection estimation of a periodic regression with a Gaussian noise
Konev, Victor; 10.1007/s10463-008-0193-1
2010-01-01
This paper considers the problem of estimating a periodic function in a continuous time regression model with an additive stationary gaussian noise having unknown correlation function. A general model selection procedure on the basis of arbitrary projective estimates, which does not need the knowledge of the noise correlation function, is proposed. A non-asymptotic upper bound for quadratic risk (oracle inequality) has been derived under mild conditions on the noise. For the Ornstein-Uhlenbeck noise the risk upper bound is shown to be uniform in the nuisance parameter. In the case of gaussian white noise the constructed procedure has some advantages as compared with the procedure based on the least squares estimates (LSE). The asymptotic minimaxity of the estimates has been proved. The proposed model selection scheme is extended also to the estimation problem based on the discrete data applicably to the situation when high frequency sampling can not be provided.
Circulation in gas-slurry column reactors
Clark, N.; Kuhlman, J.; Celik, I.; Gross, R.; Nebiolo, E.; Wang, Yi-Zun.
1990-08-15
Circulation in bubble columns, such as those used in fischer-tropsch synthesis, detracts from their performance in that gas is carried on average more rapidly through the column, and the residence time distribution of the gas in the column is widened. Both of these factors influence mass-transfer operations in bubble columns. Circulation prediction and measurement has been undertaken using probes, one-dimensional models, laser Doppler velocimetry, and numerical modeling. Local void fraction was measured using resistance probes and a newly developed approach to determining air/water threshold voltage for the probe. A tall column of eight inch diameter was constructed of Plexiglas and the distributor plate was manufactured to distribute air evenly through the base of the column. Data were gathered throughout the volume at three different gas throughputs. Bubble velocities proved difficult to measure using twin probes with cross-correlation because of radial bubble movement. A series of three-dimensional mean and RMS bubble and liquid velocity measurements were also obtained for a turbulent flow in a laboratory model of a bubble column. These measurements have been made using a three-component laser Doppler velocimeter (LDV), to determine velocity distributions non-intrusively. Finally, the gas-liquid flow inside a vertically situated circular isothermal column reactor was simulated numerically. 74 refs., 170 figs., 5 tabs.
Ocean Circulation Lynne D Talley
Talley, Lynne D.
to the topography, with low pressure in the center. Ocean currents transport heat from the tropics to the poles have gone to sea. As knowledge about ocean currents and capabilities to observe it below the surfaceOcean Circulation Lynne D Talley Volume 1, The Earth system: physical and chemical dimensions
On-chip superconducting microwave circulator from synthetic rotation
Joseph Kerckhoff; Kevin Lalumière; Benjamin J. Chapman; Alexandre Blais; K. W. Lehnert
2015-02-21
We analyze the design of a potential replacement technology for the commercial ferrite circulators that are ubiquitous in contemporary quantum superconducting microwave experiments. The lossless, lumped element design is capable of being integrated on chip with other superconducting microwave devices, thus circumventing the many performance-limiting aspects of ferrite circulators. The design is based on the dynamic modulation of DC superconducting microwave quantum interference devices (SQUIDs) that function as nearly linear, tunable inductors. The connection to familiar ferrite-based circulators is a simple frame boost in the internal dynamics' equation of motion. In addition to the general, schematic analysis, we also give an overview of many considerations necessary to achieve a practical design with a tunable center frequency in the 4-8 GHz frequency band, a bandwidth of 240 MHz, reflections at the -20 dB level, and a maximum signal power of approximately order 100 microwave photons per inverse bandwidth.
On the Patterns of Wind-Power Input to the Ocean Circulation
Roquet, Fabien
Pathways of wind-power input into the ocean general circulation are analyzed using Ekman theory. Direct rates of wind work can be calculated through the wind stress acting on the surface geostrophic flow. However, because ...
Modeling Climate and Production-related Impacts on Ice-core Beryllium-10
Modeling Climate and Production-related Impacts on Ice-core Beryllium-10 Christy Veeder Submitted Modeling Climate and Production-related Impacts on Ice-core Beryllium-10 Christy Veeder I use the Goddard Institute for Space Studies ModelE general circulation model to ex- amine the how beryllium-10, a cosmogenic
Stability of Thermohaline circulation with respect to fresh water release
Ajay Patwardhan; Vivek Tewary
2008-05-16
The relatively warm climate found in the North- Western Europe is due to the gulf stream that circulates warm saline water from southern latitudes to Europe. In North Atlantic ocean the stream gives out a large amount of heat, cools down and sinks to the bottom to complete the Thermohaline circulation. There is considerable debate on the stability of the stream to inputs of fresh water from the melting ice in Greenland and Arctic. The circulation, being switched off, will have massive impact on the climate of Europe. Intergovernmental panel on climate change (IPCC) has warned of this danger in its recent report. Our aim is to model the Thermohaline circulation at the point where it sinks in the North-Atlantic. We create a two dimensional discrete map modeling the salinity gradient and vertical velocity of the stream. We look for how a perturbation in the form of fresh water release can destabilise the circulation by pushing the velocity below a certain threshold.
A Generalized Linear Transport Model for Spatially-Correlated Stochastic Media
Anthony B. Davis; Feng Xu
2014-10-29
We formulate a new model for transport in stochastic media with long-range spatial correlations where exponential attenuation (controlling the propagation part of the transport) becomes power law. Direct transmission over optical distance $\\tau(s)$, for fixed physical distance $s$, thus becomes $(1+\\tau(s)/a)^{-a}$, with standard exponential decay recovered when $a\\to\\infty$. Atmospheric turbulence phenomenology for fluctuating optical properties rationalizes this switch. Foundational equations for this generalized transport model are stated in integral form for $d=1,2,3$ spatial dimensions. A deterministic numerical solution is developed in $d=1$ using Markov Chain formalism, verified with Monte Carlo, and used to investigate internal radiation fields. Standard two-stream theory, where diffusion is exact, is recovered when $a=\\infty$. Differential diffusion equations are not presently known when $adetection, the other in a transition from one position to another in the medium.
Stuttgart, Universität
EGU General Assembly 2014, Vienna, Austria Relative importance of coloured noise vs. model errors produced by time-variable background model errors. In particular, the effects of measurement noise models for every time epoch which provides the observables in the dimension of range acceleration
Degeneracies and scaling relations in general power-law models for gravitational lenses
Olaf Wucknitz
2002-02-20
The time delay in gravitational lenses can be used to derive the Hubble constant in a relatively simple way. The results of this method are less dependent on astrophysical assumptions than in many other methods. The most important uncertainty is related to the mass model used. We discuss a family of models with a separable radial power-law and an arbitrary angular dependence for the potential psi = r^beta * F(theta). Isothermal potentials are a special case of these models with beta=1. An additional external shear is used to take into account perturbations from other galaxies. Using a simple linear formalism for quadruple lenses, we can derive H0 as a function of the observables and the shear. If the latter is fixed, the result depends on the assumed power-law exponent according to H0 proportional to (2-beta)/beta. The effect of external shear is quantified by introducing a `critical shear' gamma_c as a measure for the amount of shear that changes the result significantly. The analysis shows, that in the general case H0 and gamma_c do not depend on the position of the lens galaxy. We discuss these results and compare with numerical models for a number of real lens systems.
Hall Effect Gyrators and Circulators
Giovanni Viola; David P. DiVincenzo
2014-03-04
The electronic circulator, and its close relative the gyrator, are invaluable tools for noise management and signal routing in the current generation of low-temperature microwave systems for the implementation of new quantum technologies. The current implementation of these devices using the Faraday effect is satisfactory, but requires a bulky structure whose physical dimension is close to the microwave wavelength employed. The Hall effect is an alternative non-reciprocal effect that can also be used to produce desired device functionality. We review earlier efforts to use an ohmically-contacted four-terminal Hall bar, explaining why this approach leads to unacceptably high device loss. We find that capacitive coupling to such a Hall conductor has much greater promise for achieving good circulator and gyrator functionality. We formulate a classical Ohm-Hall analysis for calculating the properties of such a device, and show how this classical theory simplifies remarkably in the limiting case of the Hall angle approaching 90 degrees. In this limit we find that either a four-terminal or a three-terminal capacitive device can give excellent circulator behavior, with device dimensions far smaller than the a.c. wavelength. An experiment is proposed to achieve GHz-band gyration in millimetre (and smaller) scale structures employing either semiconductor heterostructure or graphene Hall conductors. An inductively coupled scheme for realising a Hall gyrator is also analysed.
Heermann, Dieter W.
A new general model with non-spherical interactions for dense polymer systems and a potential of Bisphenol-A-Poly- carbonate, which is regarded here, the torsional potential is
Eos, Vol. 91, No. 30, 27 July 2010 Global ocean circulation is a primary
Susanto, R. Dwi
, in addition to modify- ing marine ecosystems, primary productiv- ity, and seasonal fish migration. ThereforeEos, Vol. 91, No. 30, 27 July 2010 Global ocean circulation is a primary mechanism for transporting is important for verification of ocean circulation models and of primary interest to climate research
The Circulation of Tampa Bay Driven by Buoyancy, Tides and Winds, as Simulated
Meyers, Steven D.
1 The Circulation of Tampa Bay Driven by Buoyancy, Tides and Winds, as Simulated using a Finite by rivers, tides and winds. Because of a mean wind velocity vector directed down the estuary axis we ran a parallel model experiment without winds to distinguish the estuarine circulation by gravitational
A general approach to statistical modeling of physical laws: nonparametric regression
I. Grabec
2007-04-01
Statistical modeling of experimental physical laws is based on the probability density function of measured variables. It is expressed by experimental data via a kernel estimator. The kernel is determined objectively by the scattering of data during calibration of experimental setup. A physical law, which relates measured variables, is optimally extracted from experimental data by the conditional average estimator. It is derived directly from the kernel estimator and corresponds to a general nonparametric regression. The proposed method is demonstrated by the modeling of a return map of noisy chaotic data. In this example, the nonparametric regression is used to predict a future value of chaotic time series from the present one. The mean predictor error is used in the definition of predictor quality, while the redundancy is expressed by the mean square distance between data points. Both statistics are used in a new definition of predictor cost function. From the minimum of the predictor cost function, a proper number of data in the model is estimated.
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Hartle's model within the general theory of perturbative matchings: the change in mass
Borja Reina; Raül Vera
2014-12-22
Hartle's model provides the most widely used analytic framework to describe isolated compact bodies rotating slowly in equilibrium up to second order in perturbations in the context of General Relativity. Apart from some explicit assumptions, there are some implicit, like the "continuity" of the functions in the perturbed metric across the surface of the body. In this work we sketch the basics for the analysis of the second order problem using the modern theory of perturbed matchings. In particular, the result we present is that when the energy density of the fluid in the static configuration does not vanish at the boundary, one of the functions of the second order perturbation in the setting of the original work by Hartle is not continuous. This discrepancy affects the calculation of the change in mass of the rotating star with respect to the static configuration needed to keep the central energy density unchanged.
Of Bulk and Boundaries: Generalized Transfer Matrices for Tight-Binding Models
Vatsal Dwivedi; Victor Chua
2015-10-14
We construct a generalized transfer matrix corresponding to noninteracting tight-binding lattice models, which can subsequently be used to compute the bulk bands as well as the edge states. Crucially, our formalism works even in cases where the hopping matrix is non-invertible. Following Hatsugai [PRL 71, 3697 (1993)], we explicitly construct the energy Riemann surfaces associated with the band structure for a specific class of systems which includes systems like Chern insulator, Dirac semimetal and graphene. The edge states can then be interpreted as non-contractible loops, with the winding number equal to the bulk Chern number. For these systems, the transfer matrix is symplectic, and hence we also describe the windings associated with the edge states on $Sp(2, \\mathbb{R})$ and interpret the corresponding winding number as a Maslov index.
Of Bulk and Boundaries: Generalized Transfer Matrices for Tight-Binding Models
Vatsal Dwivedi; Victor Chua
2015-10-26
We construct a generalized transfer matrix corresponding to noninteracting tight-binding lattice models, which can subsequently be used to compute the bulk bands as well as the edge states. Crucially, our formalism works even in cases where the hopping matrix is non-invertible. Following Hatsugai [PRL 71, 3697 (1993)], we explicitly construct the energy Riemann surfaces associated with the band structure for a specific class of systems which includes systems like Chern insulator, Dirac semimetal and graphene. The edge states can then be interpreted as non-contractible loops, with the winding number equal to the bulk Chern number. For these systems, the transfer matrix is symplectic, and hence we also describe the windings associated with the edge states on $Sp(2, \\mathbb{R})$ and interpret the corresponding winding number as a Maslov index.
Wakamatsu, M.; Tsujimoto, H. [Department of Physics, Faculty of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan)
2005-04-01
The theoretical predictions are given for the forward limit of the unpolarized spin-flip isovector generalized parton distribution function (E{sup u}-E{sup d})(x,{xi},t) within the framework of the chiral quark soliton model, with full inclusion of the polarization of Dirac sea quarks. We observe that [(H{sup u}-H{sup d})+(E{sup u}-E{sup d})](x,0,0) has a sharp peak around x=0, which we interpret as a signal of the importance of the pionic qq excitation with large spatial extension in the transverse direction. Another interesting indication given by the predicted distribution in combination with Ji's angular momentum sum rule is that the d quark carries more angular momentum than the u quark in the proton, which may have some relation with the physics of the violation of the Gottfried sum rule.
Lu, Jian; Sun, Lantao; Wu, Yutian; Chen, Gang
2014-03-15
The atmospheric circulation response to the global warming-like tropical upper tropospheric heating is revisited using a dry atmospheric general circulation model (AGCM) in light of a new diagnostics based on the concept of finite-amplitude wave activity (FAWA) on equivalent latitude. For a given tropical heating profile, the linear Wentzel-Kramers-Brillouin (WKB) wave refraction analysis sometimes gives a very different and even opposite prediction of the eddy momentum flux response to that of the actual full model simulation, exposing the limitation of the traditional linear approach in understanding the full dynamics of the atmospheric response under global warming. The implementation of the FAWA diagnostics reveals that in response to the upper tropospheric heating, effective diffusivity, a measure of the mixing efficiency, increases and advances upward and poleward in the subtropics and the resultant enhancement and the poleward encroachment of eddy potential vorticity mixing leads to a poleward displaced potential vorticity (PV) gradient peak in the upper troposphere. The anomalous eddy PV flux, in balance with the PV dissipation, gives rise to a poleward shift in the eddy-driven jet and eddy-driven mean meridional circulation. Sensitivity experiments show that these irreversible dissipation processes in the upper troposphere are robust, regardless of the width of the tropical heating.
Yock, Adam D. Kudchadker, Rajat J.; Rao, Arvind; Dong, Lei; Beadle, Beth M.; Garden, Adam S.; Court, Laurence E.
2014-05-15
Purpose: The purpose of this work was to develop and evaluate the accuracy of several predictive models of variation in tumor volume throughout the course of radiation therapy. Methods: Nineteen patients with oropharyngeal cancers were imaged daily with CT-on-rails for image-guided alignment per an institutional protocol. The daily volumes of 35 tumors in these 19 patients were determined and used to generate (1) a linear model in which tumor volume changed at a constant rate, (2) a general linear model that utilized the power fit relationship between the daily and initial tumor volumes, and (3) a functional general linear model that identified and exploited the primary modes of variation between time series describing the changing tumor volumes. Primary and nodal tumor volumes were examined separately. The accuracy of these models in predicting daily tumor volumes were compared with those of static and linear reference models using leave-one-out cross-validation. Results: In predicting the daily volume of primary tumors, the general linear model and the functional general linear model were more accurate than the static reference model by 9.9% (range: ?11.6%–23.8%) and 14.6% (range: ?7.3%–27.5%), respectively, and were more accurate than the linear reference model by 14.2% (range: ?6.8%–40.3%) and 13.1% (range: ?1.5%–52.5%), respectively. In predicting the daily volume of nodal tumors, only the 14.4% (range: ?11.1%–20.5%) improvement in accuracy of the functional general linear model compared to the static reference model was statistically significant. Conclusions: A general linear model and a functional general linear model trained on data from a small population of patients can predict the primary tumor volume throughout the course of radiation therapy with greater accuracy than standard reference models. These more accurate models may increase the prognostic value of information about the tumor garnered from pretreatment computed tomography images and facilitate improved treatment management.
On the circulation and tidal flushing of Mobile Bay, Alabama
Austin, George Belden
1953-01-01
of Symbols, Tables ~ . . . I, INTRODUCTION Historical B. Classification of Estuaries C. Ob]ectives II. GENERAL DISCUSSION OF NOBILE BAY A. Geomorphological B. Geological C. Biological iii ~ ~ vi ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ o sic.... Collection of Data 27 2B V, ANALYSIS OF THE DATA A. Methods B. Distribution of Temperature, Salinity, and Fresh Water Page 30 30 C. Circulation D. Mass Transport . E. Tidal Flushing of Mobile Bay . VI ~ SUMMAHY AND CONCLUSIONS VII, BIBLIOGRAPHY...
Circulation in Enewetak Atoll lagoon
Atkinson, M.; Smith, S.V.; Stroup, E.D.
1981-11-01
Currents at Enewetak Atoll, Marshall Islands, were measured on the reef margins, in the channels, and in the lagoon. Lagoon circulation is dominated by wind-driven downwind surface flow and an upwind middepth return flow. This wind-driven flow has the characteristics of an Ekman spiral in an enclosed sea. Lagoon flushing is accomplished primarily by surf-driven water input over the windward (eastern) reefs and southerly drift out the South Channel. Mean water residence time is 1 month, while water entering the northern portion of the atoll takes about 4 months to exit.
Crauel, Hans
A General Asset-Liability Management Model for the Efficient Simulation of Portfolios of Life and a stronger competition have increased the importance of stochastic asset-liability management (ALM) models development of life insurance products. Keywords: asset-liability management, participating policies
Reversing the Circulation of Magnetic Vortices
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
at the ALS, researchers have shown for the first time how to use pulsed magnetic fields to reverse the circulation. Taming the Whirlwind Although magnetic vortices may seem...
L General Permit Parking LOT A General Permit Parking LOT C General Permit Parking LOT R Reserved Parking LOT D Faculty/Staff Parking LOT K General Permit Parking LOT J Reserved Parking PV LOT General Parking after 3 p.m. WEST CAMPUS PARKING LOT O General Permit Parking LOT M General Permit Parking LOT P
98 28 28 60 96 31 7 23 LOT L General Permit Parking LOT A General Permit Parking LOT C General Permit Parking LOT R Reserved Parking LOT D Faculty/Staff Parking LOT K General Permit Parking LOT J Reserved Parking PV LOT General Parking after 3 p.m. WEST CAMPUS PARKING LOT O General Permit Parking LOT M General
Bolshov, L.; Kondratenko, P.; Matveev, L.; Pruess, K.
2008-09-01
In this study, new elements were developed to generalize the dual-porosity model for moisture infiltration on and solute transport in unsaturated rocks, taking into account fractal aspects of the percolation process. Random advection was considered as a basic mechanism of solute transport in self-similar fracture systems. In addition to spatial variations in the infiltration velocity field, temporal fluctuations were also taken into account. The rock matrix, a low-permeability component of the heterogeneous geologic medium, acts as a trap for solute particles and moisture. Scaling relations were derived for the moisture infiltration flux, the velocity correlation length, the average velocity of infiltration, and the velocity correlation function. The effect of temporal variations in precipitation intensity on the infiltration processes was analyzed. It showed that the mode of solute transport is determined by the power exponent in the advection velocity correlation function and the dimensionality of the trapping system, both of which may change with time. Therefore, depending on time, various transport regimes may be realized: superdiffusion, subdiffusion, or classical diffusion. The complex structure of breakthrough curves from changes in the transport regimes was also examined. A renormalization of the solute source strength due to characteristic fluctuations of highly disordered media was established.
Scott, Jeffery R.
The response of the ocean’s meridional overturning circulation (MOC) to increased greenhouse gas forcing is examined using a coupled model of intermediate complexity, including a dynamic 3D ocean subcomponent. Parameters ...
Modeling production and climate-related impacts on Be concentration in ice cores
strength and the solar activity modulation parameter (f), CO2, sea surface temperatures, and volcanic for studying changes in solar output. However, interpreting 10 Be ice core records on centennial timescales. By using the Goddard Institute for Space Studies ModelE general circulation model to selectively vary
The Maine Coastal Current: Spring Climatological Circulation
The Maine Coastal Current: Spring Climatological Circulation Daniel R. Lynch, Monica J. Holboke in the Gulf of Maine, with special emphasis on its coastal current in the periods MarchApril and May of Maine cyclonic circulation is persistent, with significant bimonthly modulation of key Maine Coastal
Downhole material injector for lost circulation control
Glowka, D.A.
1991-01-01
This invention is comprised of an apparatus and method for simultaneously and separately emplacing two streams of different materials through a drillstring in a borehole to a downhole location for lost circulation control. The two streams are mixed outside the drillstring at the desired downhole location and harden only after mixing for control of a lost circulation zone.
Microfluidic Platforms for Capturing Circulating Tumor Cells
Tang, William C
Microfluidic Platforms for Capturing Circulating Tumor Cells Sweta Gupta, Allison C. Baker-cost microfluidic device that can be used to isolate and capture circulating tumor cells (CTCs) from whole blood. The device was made from polydimethylsiloxane (PDMS) consisting of a microfluidic channel with microposts
Downhole material injector for lost circulation control
Glowka, D.A.
1994-09-06
Apparatus and method are disclosed for simultaneously and separately emplacing two streams of different materials through a drill string in a borehole to a downhole location for lost circulation control. The two streams are mixed outside the drill string at the desired downhole location and harden only after mixing for control of a lost circulation zone. 6 figs.
Wave Energy Converter (WEC) Array Effects on Wave Current and Sediment Circulation: Monterey Bay CA.
Roberts, Jesse D.; Jones, Craig; Magalen, Jason
2014-09-01
The goal s of this study were to develop tools to quantitatively characterize environments where wave energy converter ( WEC ) devices may be installed and to assess e ffects on hydrodynamics and lo cal sediment transport. A large hypothetical WEC array was investigated using wave, hydrodynamic, and sediment transport models and site - specific average and storm conditions as input. The results indicated that there were significant changes in sediment s izes adjacent to and in the lee of the WEC array due to reduced wave energy. The circulation in the lee of the array was also altered; more intense onshore currents were generated in the lee of the WECs . In general, the storm case and the average case show ed the same qualitative patterns suggesting that these trends would be maintained throughout the year. The framework developed here can be used to design more efficient arrays while minimizing impacts on nearshore environmen ts.
the polymer with nanoinclusions of carbon nanotubes and graphene sheets and other structures. PolymerUsing Theory to Model Polymer Properties There are two general themes to this research: (1) polymer degradation that occurs when polymers are exposed to low earth orbit conditions, and (2) polymer mechanical
Wisconsin at Madison, University of
Multivariate General Linear Models (MGLM) on Riemannian Manifolds with Applications to Statistical range of such methods by deriv- ing schemes for multivariate multiple linear regression -- a manifold ] , ^ = ¯y - ^¯x. (2) If x and y are multivariates, one can easily replace the mul- tiplication and division
Jayaram, Bhyravabotla
Solvation Free Energy of Biomacromolecules: Parameters for a Modified Generalized Born Model provides rapid estimates of the electrostatic free energies of solvation for diverse molecules of parameters compatible with the AMBER force field is described. The method is used to estimate free energies
Trampedach, Regner; Collet, Remo; Nordlund, Åke; Stein, Robert F
2013-01-01
Present grids of stellar atmosphere models are the workhorses in interpreting stellar observations, and determining their fundamental parameters. These models rely on greatly simplified models of convection, however, lending less predictive power to such models of late type stars. We present a grid of improved and more reliable stellar atmosphere models of late type stars, based on deep, 3D, convective, stellar atmosphere simulations. This grid is to be used in general for interpreting observations, and improve stellar and asteroseismic modeling. We solve the Navier Stokes equations in 3D and concurrent with the radiative transfer equation, for a range of atmospheric parameters, covering most of stellar evolution with convection at the surface. We emphasize use of the best available atomic physics for quantitative predictions and comparisons with observations. We present granulation size, convective expansion of the acoustic cavity, asymptotic adiabat, as function of atmospheric parameters. These and other re...
Improved Indoor Tracking Based on Generalized t-Distribution Noise Model
Shuo, Liu; Le, Yin; Khuen, Ho Weng; Voon, Ling Keck
2015-01-01
function. Industrial & engineering chemistry research, 42(model. Industrial & Engineering Chemistry Research, 52(11):
Improved Indoor Tracking Based on Generalized t-Distribution Noise Model
Shuo, Liu; Le, Yin; Khuen, Ho Weng; Voon, Ling Keck
2015-01-01
objective function. Industrial & engineering chemistryfunction approac. Industrial & Engineering Chem- istrynoise model. Industrial & Engineering Chemistry Research,
Thermodynamical description of modified generalized Chaplygin gas model of dark energy
H. Ebadi; H. Moradpour
2015-04-15
We consider a universe filled by a modified generalized Chaplygin gas together with a pressureless dark matter component. We get a thermodynamical interpretation for the modified generalized Chaplygin gas confined to the apparent horizon of FRW universe, whiles dark sectors do not interact with each other. Thereinafter, by taking into account a mutual interaction between the dark sectors of the cosmos, we find a thermodynamical interpretation for interacting modified generalized Chaplygin gas. Additionally, probable relation between the thermal fluctuations of the system and the assumed mutual interaction is investigated. Finally, we show that if one wants to solve the coincidence problem by using this mutual interaction, then the coupling constants of the interaction will be constrained. The corresponding constraint is also addressed. Moreover, the thermodynamic interpretation of using either a generalized Chaplygin gas or a Chaplygin gas to describe dark energy is also addressed throughout the paper.
RF power recovery feedback circulator
Sharamentov, Sergey I. (Bolingbrook, IL)
2011-03-29
A device and method for improving the efficiency of RF systems having a Reflective Load. In the preferred embodiment, Reflected Energy from a superconducting resonator of a particle accelerator is reintroduced to the resonator after the phase of the Reflected Energy is aligned with the phase of the Supply Energy from a RF Energy Source. In one embodiment, a Circulator is used to transfer Reflected Energy from the Reflective Load into a Phase Adjuster which aligns the phase of the Reflected Energy with that of the Supply Energy. The phase-aligned energy is then combined with the Supply Energy, and reintroduced into the Reflective Load. In systems having a constant phase shift, the Phase Adjuster may be designed to shift the phase of the Reflected Energy by a constant amount using a Phase Shifter. In systems having a variety (variable) phase shifts, a Phase Shifter controlled by a phase feedback loop comprising a Phase Detector and a Feedback Controller to account for the various phase shifts is preferable.
Menke, William
trivially. 4. The damped least squares generalized inverse has the form Note that since is symmetric, its least squares generalized inverse % GMG = (G'*G + epsi*eye(M,M)) \\ G' epsi = 0.1; A = (G'*G + epsi data kernel s=0.1; G=random('Normal',0, s, N, M ) + eye(N,M); % stddev of data sigmad = 1; % use damped
CIRCULATING MOVING BED COMBUSTION PROOF OF CONCEPT
Jukkola, Glen
2010-06-30
Circulating Moving Bed (CMB) combustion technology has its roots in traditional circulating fluidized bed technology and involves a novel method of solid fuel combustion and heat transfer. CMB technology represents a step change in improved performance and cost relative to conventional PC and FBC boilers. The CMB heat exchanger preheats the energy cycle working fluid, steam or air, to the high temperature levels required in systems for advanced power generation. Unique features of the CMB are the reduction of the heat transfer surfaces by about 60% as a result of the enhanced heat transfer rates, flexibility of operation, and about 30% lower cost over existing technology. The CMB Phase I project ran from July 2001 through March 2003. Its objective was to continue development of the CMB technology with a series of proof of concept tests. The tests were conducted at a scale that provided design data for scale up to a demonstration plant. These objectives were met by conducting a series of experiments in ALSTOM Power’s Multi-use Test Facility (MTF). The MTF was modified to operate under CMB conditions of commercial interest. The objective of the tests were to evaluate gas-to-solids heat transfer in the upper furnace, assess agglomeration in the high temperature CMB bubbling bed, and evaluate solids-to-tube heat transfer in the moving bed heat exchanger. The Phase I program results showed that there are still some significant technical uncertainties that needed to be resolved before the technology can be confidently scaled up for a successful demonstration plant design. Work remained in three primary areas: • scale up of gas to solid heat transfer • high temperature finned surface design • the overall requirements of mechanical and process design. The CMB Phase II workscope built upon the results of Phase I and specifically addressed the remaining technical uncertainties. It included a scaled MTF heat transfer test to provide the necessary data to scale up gas-to-solids heat transfer. A stress test rig was built and tested to provide validation data for a stress model needed to support high temperature finned surface design. Additional cold flow model tests and MTF tests were conducted to address mechanical and process design issues. This information was then used to design and cost a commercial CMB design concept. Finally, the MBHE was reconfigured into a slice arrangement and tested for an extended duration at a commercial CFB plant.
focus. There, several external sources of circulation have been identified (wind, deep convection using a layered, hydrostatic ocean model. The specific experiments planned are (i), the concentration, also optically. The fourth set of experiments requires special comment. Numerical modeling
Lautenberger, Chris; Fernandez-Pello, Carlos
2006-01-01
State-of-the-Art in Pyrolysis Modeling of LignocellulosicC. & Fernandez-Pello, A.C. , “Pyrolysis Modeling, ThermalKuo, J.T. & Hsi, C. -L. , “Pyrolysis and Ignition of Single
Testing Lack-of-Fit of Generalized Linear Models via Laplace Approximation
Glab, Daniel Laurence
2012-07-16
In this study we develop a new method for testing the null hypothesis that the predictor function in a canonical link regression model has a prescribed linear form. The class of models, which we will refer to as canonical ...
Allauzen, Cyril
applications or for adaptation purposes, one often needs to construct a language model based on the out- put library for language modeling, the GRM Library, that includes many other text and grammar processing classification. In all cases, a language model is used in combination with other in- formation sources to rank
PHYSICS OF OCEAN CIRCULATION Instructor: S. Riser
Riser, Stephen C.
Topography Tides Wind Geothermal heating Surface flows elsewhere #12;How deep is the ocean? The average ocean circulation #12;UNITS Horizontal distance: km (= 105 cm) Vertical distance: m Velocity: cm/sec Density: g/cm3
Circulation and convection in the Irminger Sea
Våge, Kjetil
2010-01-01
Aspects of the circulation and convection in the Irminger Sea are investigated using a variety of in-situ, satellite, and atmospheric reanalysis products. Westerly Greenland tip jet events are intense, small-scale wind ...
Continuous Circulation System: a new enabling technology
Kenawy, Walid F.
2002-01-01
of drilled cuttings. It also causes some operating problems in underbalanced drilling. A new technology in drilling has been introduced through a joint industry project to overcome problems caused by interruption of circulation. This technology...
Cops and Robber on Circulant Graphs
Bonato, Anthony
Edward Island #12;Cops and Robber Played on a finite, simple graph Cops have perfect information TwoCops and Robber on Circulant Graphs Shannon Fitzpatrick John Paul Larkin University of Prince
Laura Sampson; Neil Cornish; Nicolas Yunes
2013-03-05
We study generic tests of strong-field General Relativity using gravitational waves emitted during the inspiral of compact binaries. Previous studies have considered simple extensions to the standard post-Newtonian waveforms that differ by a single term in the phase. Here we improve on these studies by (i) increasing the realism of injections and (ii) determining the optimal waveform families for detecting and characterizing such signals. We construct waveforms that deviate from those in General Relativity through a series of post-Newtonian terms, and find that these higher-order terms can affect our ability to test General Relativity, in some cases by making it easier to detect a deviation, and in some cases by making it more difficult. We find that simple single-phase post-Einsteinian waveforms are sufficient for detecting deviations from General Relativity, and there is little to be gained from using more complicated models with multiple phase terms. The results found here will help guide future attempts to test General Relativity with advanced ground-based detectors.
Vassilis S. Geroyannis; Vasileios G. Karageorgopoulos
2014-09-30
We develop a "hybrid approximative scheme" in the framework of the post-Newtonian approximation for computing general-relativistic polytropic models simulating neutron stars in critical rigid rotation. We treat the differential equations governing such a model as a "complex initial value problem", and we solve it by using the so-called "complex-plane strategy". We incorporate into the computations the complete solution for the relativistic effects, this issue representing a significant improvement with regard to the classical post-Newtonian approximation, as verified by extended comparisons of the numerical results.
de Souza, R S; Buelens, B; Riggs, J D; Cameron, E; Ishida, E E O; Chies-Santos, A L; Killedar, M
2015-01-01
In this paper, the third in a series illustrating the power of generalized linear models (GLMs) for the astronomical community, we elucidate the potential of the class of GLMs which handles count data. The size of a galaxy's globular cluster population $N_{\\rm GC}$ is a prolonged puzzle in the astronomical literature. It falls in the category of count data analysis, yet it is usually modelled as if it were a continuous response variable. We have developed a Bayesian negative binomial regression model to study the connection between $N_{\\rm GC}$ and the following galaxy properties: central black hole mass, dynamical bulge mass, bulge velocity dispersion, and absolute visual magnitude. The methodology introduced herein naturally accounts for heteroscedasticity, intrinsic scatter, errors in measurements in both axes (either discrete or continuous), and allows modelling the population of globular clusters on their natural scale as a non-negative integer variable. Prediction intervals of 99% around the trend for e...
Chandan Mondal; Dipankar Chakrabarti
2015-06-17
We present a study of the generalized parton distributions for the quarks in a proton in both momentum and position spaces using the light-front wave functions of a quark-diquark model for the nucleon predicted by the soft-wall model of AdS/QCD. The results are compared with the soft-wall AdS/QCD model of proton GPDs for zero skewness. We also calculate the GPDs for nonzero skewness. We observe that the GPDs have a diffraction pattern in longitudinal position space, as seen before in other models. Then we present a comparitive study of the nucleon charge and anomalous magnetization densities in the transverse plane. Flavor decompositions of the form factors and transverse densities are also discussed.
Hassan Amirhashchi
2010-11-26
Locally rotationally symmetric (L.R.S.) Bianchi type II stiff fluid cosmological model is investigated. To get the deterministic model of the universe, we have assumed a condition $A=B^{m}$ between metric potentials $A,~B$ where $n$ is the constant. It is shown that the vacuum energy density $\\Lambda$ is positive and proportional to $\\frac{1}{t^{2}}$. The values of deceleration parameter $q$, matter-energy density $\\Omega_{m}$ and dark-energy density $\\Omega_{\\Lambda}$ are found to be in good agreement with the values obtain from 5-years WMAP observations. the predicted value of the jerk parameter agrees with the SNLS SNIa and X-ray galaxy cluster distance data but does not with the SNIa gold sample data. In general, the model represent accelerating, shearing and non-rotating universe.The physical and geometrical behavior of these models are also discussed.
A Flexible Climate Model For Use In Integrated Assessments Andrei P. Sokolov and Peter H. Stone
penetration into the deep ocean is comparable with that of other significant uncertainties. 1. Introduction with coupled atmosphere ocean general circulation models (AOGCMs) because of their tremendous computer resource with a diffusive ocean model developed for use in the integrated framework of the MIT Joint Program on the Science
A new general model with non-spherical interactions for dense polymer systems and a
Heermann, Dieter W.
parametrization for Bisphenol-A-Polycarbonate Klaus M. Zimmer, Andreas Linke and Dieter W. Heermann Institut fur modeling of the monomer units. We apply the model to the special case of Bisphenol-A-Polycarbonate BPA material, we describe the approach for the Bisphenol-A-Polycarbonate BPA-PC and a variation
Bledsoe, Brian
The Nature Conservancy, Fort Collins, Colorado USA ABSTRACT Dams and water diversions can dramatically alter the hydraulic habitats of stream ecosystems. Predicting how water depth and velocity respond to flow alteration is possible using hydraulic models, such as Physical Habitat Simulation (PHABSIM); however, such models
Impact of cloud radiative heating on East Asian summer monsoon circulation
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Guo, Zhun; Zhou, Tianjun; Wang, Minghuai; Qian, Yun
2015-07-17
The impacts of cloud radiative heating on East Asian Summer Monsoon (EASM) over the southeastern China (105°-125°E, 20°-35°N) are explained by using the Community Atmosphere Model version 5 (CAM5). Sensitivity experiments demonstrate that the radiative heating of clouds leads to a positive effect on the local EASM circulation over southeastern China. Without the radiative heating of cloud, the EASM circulation and precipitation would be much weaker than that in the normal condition. The longwave heating of clouds dominates the changes of EASM circulation. The positive effect of clouds on EASM circulation is explained by the thermodynamic energy equation, i.e. themore »different heating rate between cloud base and cloud top enhances the convective instability over southeastern China, which enhances updraft consequently. The strong updraft would further result in a southward meridional wind above the center of the updraft through Sverdrup vorticity balance.« less
OLAF _ A General Modeling System to Evaluate and Optimize the Location of an Air
Fliege, Jörg
........................17 3.1.1The Standard Model ....................17 3.1.2Metabolism.1.2The Objective Function ..................40 5.1.3The Gradient of the Objective Function
Re-analysis of deep excavation collapse using a generalized effective stress soil model
Corral Jofré, Gonzalo Andrés
2010-01-01
This thesis re-analyzes the well-documented failure of a 30m deep braced excavation underconsolidated marine clay. Prior analyses of the collapse of the Nicoll Highway have relied on simplified soil models with undrained ...
A general model of resource production and exchange in systems of interdependent specialists.
Conrad, Stephen Hamilton; Finley, Patrick D.; Beyeler, Walter Eugene; Brown, Theresa Jean; Glass, Robert John, Jr.; Breen, Peter; Kuypers, Marshall; Norton, Matthew David; Quach, Tu-Thach; Antognoli, Matthew; Mitchell, Michael David
2011-11-01
Infrastructures are networks of dynamically interacting systems designed for the flow of information, energy, and materials. Under certain circumstances, disturbances from a targeted attack or natural disasters can cause cascading failures within and between infrastructures that result in significant service losses and long recovery times. Reliable interdependency models that can capture such multi-network cascading do not exist. The research reported here has extended Sandia's infrastructure modeling capabilities by: (1) addressing interdependencies among networks, (2) incorporating adaptive behavioral models into the network models, and (3) providing mechanisms for evaluating vulnerability to targeted attack and unforeseen disruptions. We have applied these capabilities to evaluate the robustness of various systems, and to identify factors that control the scale and duration of disruption. This capability lays the foundation for developing advanced system security solutions that encompass both external shocks and internal dynamics.
A generalized nutrition model for Odocoileus deer and its application in a natural environment
Applegath, Matthew Thomas
2002-01-01
A model of protein and energy balance was created for Odocoileus deer [white-tailed deer (Odocoileus virginianus), mule deer (O. hemionus), and black-tailed deer (O. h. columbianus, O. h. sitkensis)] capable of predicting changes in body weight...
Inference for Clustered Mixed Outcomes from a Multivariate Generalized Linear Mixed Model
Chen, Hsiang-Chun
2013-08-01
. Bayesian methods are widely used techniques for analyzing MGLMM. The need for noninformative priors arises when there is insufficient prior information on the model parameters. Another aim of this study is to propose an approximate uniform shrinkage prior...
Self-repelling fractional Brownian motion - a generalized Edwards model for chain polymers
Jinky Bornales; Maria João Oliveira; Ludwig Streit
2011-12-10
We present an extension of the Edwards model for conformations of individual chain molecules in solvents in terms of fractional Brownian motion, and discuss the excluded volume effect on the end-to-end length of such trajectories or molecules.
A general approach to develop reduced order models for simulation of solid oxide fuel cell stacks
Pan, Wenxiao; Bao, Jie; Lo, Chaomei; Lai, Canhai; Agarwal, Khushbu; Koeppel, Brian J.; Khaleel, Mohammad A.
2013-06-15
A reduced order modeling approach based on response surface techniques was developed for solid oxide fuel cell stacks. This approach creates a numerical model that can quickly compute desired performance variables of interest for a stack based on its input parameter set. The approach carefully samples the multidimensional design space based on the input parameter ranges, evaluates a detailed stack model at each of the sampled points, and performs regression for selected performance variables of interest to determine the responsive surfaces. After error analysis to ensure that sufficient accuracy is established for the response surfaces, they are then implemented in a calculator module for system-level studies. The benefit of this modeling approach is that it is sufficiently fast for integration with system modeling software and simulation of fuel cell-based power systems while still providing high fidelity information about the internal distributions of key variables. This paper describes the sampling, regression, sensitivity, error, and principal component analyses to identify the applicable methods for simulating a planar fuel cell stack.
Agarwala, R. [National Institutes of Health, Bethesda, MD (United States); Batzoglou, S. [MIT Lab. for Computer Science, Cambridge, MA (United States); Dancik, V. [Univ. of Southern California, Los Angeles, CA (United States)] [and others
1997-12-01
A long standing problem in molecular biology is to determine the three-dimensional structure of a protein, given its amino acid sequence. A variety of simplifying models have been proposed abstracting only the {open_quotes}essential physical properties{close_quotes} of real proteins. In these models, the three dimensional space is often represented by a lattice. Residues which are adjacent in the primary sequence (i.e. covalently linked) must be placed at adjacent points in the lattice. A conformation of a protein is simply a self-avoiding walk along the lattice. The protein folding problem STRING-FOLD is that of finding a conformation of the protein sequence on the lattice such that the overall energy is minimized, for some reasonable definition of energy. This formulation leaves open the choices of a lattice and an energy function. Once these choices are made, one may then address the algorithmic complexity of optimizing the energy function for the lattice. For a variety of such simple models, this minimization problem is in fact NP-hard. In this paper, we consider the Hydrophobic-Polar (HP) Model introduced by Dill. The HP model abstracts the problem by grouping the 20 amino acids into two classes: hydrophobic (or non-polar) residues and hydrophilic (or polar) residues. For concreteness, we will take our input to be a string from (H,P){sup +}, where P represents polar residues, and H represents hydrophobic residues. Dill et.al. survey the literature analyzing this model. 8 refs., 2 figs., 1 tab.
Factored Language Models and Generalized Parallel Backoff Jeff A. Bilmes Katrin Kirchhoff
Washington at Seattle, University of
model, a word is viewed as a vec- tor of k factors, so that wt {f1 t , f2 t , . . . , fK t }. Fac- tors. An FLM is a model over factors, i.e., p(f1:K t |f1:K t-1:t-n), that can be factored as a product of probabilities of the form p(f|f1, f2, . . . , fN ). Our task is twofold: 1) find an appropriate set of factors
Richard P. Sear
2013-07-29
Models without an explicit time dependence, called singular models, are widely used for fitting the distribution of temperatures at which water droplets freeze. In 1950 Levine developed the original singular model. His key assumption was that each droplet contained many nucleation sites, and that freezing occurred due to the nucleation site with the highest freezing temperature. The fact that freezing occurs due to the maximum value out of large number of nucleation temperatures, means that we can apply the results of what is called extreme-value statistics. This is the statistics of the extreme, i.e., maximum or minimum, value of a large number of random variables. Here we use the results of extreme-value statistics to show that we can generalise Levine's model to produce the most general singular model possible. We show that when a singular model is a good approximation, the distribution of freezing temperatures should always be given by what is called the generalised extreme-value distribution. In addition, we also show that the distribution of freezing temperatures for droplets of onesize, can be used to make predictions for the scaling of the median nucleation temperature with droplet size, and vice versa.
Finite-temperature properties of the generalized Falicov-Kimball model S. El Shawish,1
Bonèa, Janez
Laboratory, Los Alamos, New Mexico 87545, USA Received 4 July 2003; published 18 November 2003 in intermediate valence com- pounds. A renewed interest in this model started when Por- tengen et al.2 suggested an important role in defining the nature of the low energy spectrum of the ferroelectric state.4 For simplicity
Separating expansion from contraction: generalized TOV condition, LTB models with pressure and CDM
Paris-Sud XI, UniversitÃ© de
, we adopt the Generalised PainlevÃ©-Gullstrand (hereafter GPG) formalism used in Lasky & Lun [6], which TO LTB MODELS IN GPG SYSTEM We consider a spherically symmetric Generalised LemaÃ®tre-Tolman-Bondi metric to include pressure. Performing an ADM 3+1 splitting in the GPG coordinates [6] , the metric reads ds2 = -(t
Negative specific heat in a quasi-2D generalized vorticity model T. D. Andersen
Lim, Chjan C.
) model for the unbounded plane under strong magnetic confinement. We derive the specific heat using, this results in a runaway reaction leading to a collapse of the cluster. In a magnetic fusion system or other- found implications for fusion where extreme confinement is critical to a sustained reaction
Sanandaji, Borhan M.
Ancillary Service He Hao, Borhan M. Sanandaji, Kameshwar Poolla, and Tyrone L. Vincent Abstract for providing various ancillary services to the grid. In this work, we study aggregate modeling, and uncontrollability of renewable resources. To ensure the func- tionality and reliability of the grid, more ancillary
Computable General Equilibrium Models for the Analysis of Energy and Climate Policies
Wing, Ian Sue
Dept. of Geography and Environment, Boston University Joint Program on the Science and Policy of Global Change, MIT Prepared for the International Handbook of Energy Economics Abstract This chapter is a simple algebraic framework of a CGE model is developed from microeconomic fundamentals, and employed to illustrate
Internal noise driven generalized Langevin equation from a nonlocal continuum model
Saikat Sarkar; Shubhankar Roy Chowdhury; Debasish Roy; Ram Mohan Vasu
2015-03-10
Starting with a micropolar formulation, known to account for nonlocal microstructural effects at the continuum level, a generalized Langevin equation (GLE) for a particle, describing the predominant motion of a localized region through a single displacement degree-of-freedom (DOF), is derived. The GLE features a memory dependent multiplicative or internal noise, which appears upon recognising that the micro-rotation variables possess randomness owing to an uncertainty principle. Unlike its classical version, the new GLE qualitatively reproduces the experimentally measured fluctuations in the steady-state mean square displacement of scattering centers in a polyvinyl alcohol slab. The origin of the fluctuations is traced to nonlocal spatial interactions within the continuum. A constraint equation, similar to a fluctuation dissipation theorem (FDT), is shown to statistically relate the internal noise to the other parameters in the GLE.
N. Razzaghi
2015-05-17
We propose a phenomenological model of the Dirac neutrino mass matrix based on the Fridberg-Lee neutrino mass model at a special point. In this case, the Fridberg-Lee model reduces to the Democratic mass matrix with the $S_3$ permutation family symmetry. The Democratic mass matrix has an experimentally unfavored degenerate mass spectrum on the base of tribimaximal mixing matrix. We rescue the model to find a nondegenerate mass spectrum by adding the breaking mass term as preserving the twisted Fridberg-Lee symmetry. The tribimaximal mixing matrix can be also realized. Exact tribimaximal mixing leads to $\\theta_{13}=0$. However, the results from Daya Bay and RENO experiments have established a nonzero value for $\\theta_{13}$. Keeping the leading behavior of $U$ as tribimaximal, we use Broken Democratic neutrino mass model. We characterize a perturbation mass matrix which is responsible for a nonzero $\\theta_{13}$ along with CP violation, besides the solar neutrino mass splitting has been resulted from it. We consider this work in two stages: In the first stage, we obtain the perturbation mass matrix with real components which breaks softly the $\\mu-\\tau$ symmetry and this leads to a nonzero value for $\\theta_{13}$. In the second stage, we extend the perturbation mass matrix to a complex symmetric matrix which leads to CP violation. Therefore obtain a realistic neutrino mixing matrix with $\\theta_{23}=45^\\circ$. We obtain the solar mass splitting, the ordering of the neutrino masses is inverted. Using only two sets of the experimental data, we can fix all of the parameters of mass matrix and predict the masses of neutrinos and phases. These predictions include the following: $m_{1}\\approx(4.82-4.93)10^{-2}eV $, $|m_2|\\approx(4.90-5.01)10^{-2} eV$, $m_3\\approx0$ and, $\\phi\\approx(0.687^\\circ-10.31^\\circ)$ as the origin of the Majorana phases.
Jensen, Tommy
steps are taken to reduce the potential energy barrier to sacks crossing one another, the model the northern boundary for a time. Taking advantage of the new mixing scheme and lessons learned from Institute of Technol- ogy general circulation model (MITgcm). The SSOM and the MITgcm produce similar wind
Description of FLIPSIM V: a General Firm Level Policy Simulation Model.
Richardson, James W.; Nixon, Clair J.
1986-01-01
be taken for all purchases of equipment, as well as investment tax credit. If equipment or cattle are sold rather than traded in, the capital. gains or losses realized from the sale are calculated and used in computing personal income taxes. Depreciation...) standard tax tables. The model selects the tax strategy which results in the lower income tax liability. All investment tax credit allowances are deducted from the regular income tax liability with the result being compared to the income tax liability...
Examining the Generalized Waring Model for the Analysis of Traffic Crashes
Peng, Yichuan
2013-05-03
Figure 5.19 Sensitivity analysis of covariate ADT for Michigan data ........................ 95 Figure 6.1 Comparison of rankings between NB and GW models ............................. 99 x LIST OF TABLES... sites based on the available information, such as traffic flow and other road geometric variables. They also can be used to investigate specific or significant effects of the variables on the risk of the collision. In addition, the number of 2...
Weyermann, D.L.; Fight, R.D.; Garrett, F.D.
1991-08-01
This paper instructs resource analysts on using the southeast Alaska multiresource model (SAMM). SAMM is an interactive microcomputer program that allows users to explore relations among several resources in southeast Alaska (timber, anadromous fish, deer, and hydrology) and the effects of timber management activities (logging, thinning, and road building) on those relations and resources. This guide assists users in installing SAMM on a microcomputer, developing input data files, making simulation runs, and strong output data for external analysis and graphic display.
Recent technology improvements in Exxon's circulating zinc-bromine battery system
Bellows, R.J.
1981-01-01
Recent electrode and electrolyte performance on 500 wH and 3 kWh units indicates that Exxon's circulating zinc-bromine battery in 20 kWh designs will be capable of high energy density (65 to 70 wH/kg), and turn-around efficiency (65 to 70%). This performance, coupled with recent factory cost projections of $28/kWh (exclusive of R.O.I. and various indirect overheads), makes zinc/bromine an attractive advanced battery candidate for not only photovoltaic, but also electric vehicle and bulk energy storage applications. Recent technical developments in this program may be generally useful in other circulating electrolyte systems.
Horwitz, Rachel Mandy
2012-01-01
Observations from a three-year field program on the inner shelf south of Martha's Vineyard, MA and a numerical model are used to describe the effect of stratification on inner shelf circulation, transport, and sediment ...
Experimental analysis of the mechanics of reverse circulation air lift
Zeineddine, Talal Ibrahim
1980-01-01
investigation of the two-phase air-water flow in the lifting pipe of an air lift pump model was conducted. The effect of the diffuser design on the efficiency of the pump was then determined. The experimental study consisted of measuring the void frac- tion... circulation air lift device as a function of diffuser configuration. The two-phase flow in the vertical lifting pipe of the pump was studied in detail so that the flow parameters and their variations across and along the pipe were investigated...
Renormalization of lattice-regularized quantum gravity models I. General considerations
Joshua H. Cooperman
2014-10-21
Lattice regularization is a standard technique for the nonperturbative definition of a quantum theory of fields. Several approaches to the construction of a quantum theory of gravity adopt this technique either explicitly or implicitly. A crucial complement to lattice regularization is the process of renormalization through which a continuous description of the quantum theory arises. I provide a comprehensive conceptual discussion of the renormalization of lattice-regularized quantum gravity models. I begin with a presentation of the renormalization group from the Wilsonian perspective. I then consider the application of the renormalization group in four contexts: quantum field theory on a continuous nondynamical spacetime, quantum field theory on a lattice-regularized nondynamical spacetime, quantum field theory of continuous dynamical spacetime, and quantum field theory of lattice-regularized dynamical spacetime. The first three contexts serve to identify successively the particular issues that arise in the fourth context. These issues originate in the inescability of establishing all scales solely on the basis of the dynamics. While most of this discussion rehearses established knowledge, the attention that I pay to these issues, especially the previously underappreciated role of standard units of measure, is largely novel. I conclude by briefly reviewing past studies of renormalization of lattice-regularized quantum gravity models. In the second paper of this two-part series, I illustrate the ideas presented here by proposing a renormalization group scheme for causal dynamical triangulations.
Walter Del Pozzo; John Veitch; Alberto Vecchio
2011-01-07
Second generation interferometric gravitational wave detectors, such as Advanced LIGO and Advanced Virgo, are expected to begin operation by 2015. Such instruments plan to reach sensitivities that will offer the unique possibility to test General Relativity in the dynamical, strong field regime and investigate departures from its predictions, in particular using the signal from coalescing binary systems. We introduce a statistical framework based on Bayesian model selection in which the Bayes factor between two competing hypotheses measures which theory is favored by the data. Probability density functions of the model parameters are then used to quantify the inference on individual parameters. We also develop a method to combine the information coming from multiple independent observations of gravitational waves, and show how much stronger inference could be. As an introduction and illustration of this framework - and a practical numerical implementation through the Monte Carlo integration technique of nested sampling - we apply it to gravitational waves from the inspiral phase of coalescing binary systems as predicted by General Relativity and a very simple alternative theory in which the graviton has a non-zero mass. This method can trivially (and should) be extended to more realistic and physically motivated theories.
Vertical mixing and the ocean circulation
Jones, Peter JS
Changing sources of mixing Hurricanes Tidal dissipation 2 #12;Zonal Mean Ocean Temperature 3 #12;Sandström's Theorem A circulation cannot be driven unless heat is input at a lower depth than it is lost in the ocean? Wind-driven stirring Tidal generation of internal waves Biota Hurricanes Nasa 6 #12;Sources
A General Relativistic Model for Magnetic Monopole-Infused Compact Objects
Zoran Pazameta
2012-01-30
Emergent concepts from astroparticle physics are incorporated into a classical solution of the Einstein-Maxwell equations for a binary magnetohydrodynamic fluid, in order to describe the final equilibrium state of compact objects infused with magnetic monopoles produced by proton-proton collisions within the intense dipolar magnetic fields generated by these objects during their collapse. It is found that the effective mass of such an object's acquired monopolar magnetic field is three times greater than the mass of its native fluid and monopoles combined, necessitating that the interior matter undergo a transition to a state of negative pressure in order to attain equilibrium. Assuming full symmetry between the electric and magnetic Maxwell equations yields expressions for the monopole charge density and magnetic field by direct analogy with their electrostatic equivalents; inserting these into the Einstein equations then leads to an interior metric which is well-behaved from the origin to the surface, where it matches smoothly to an exterior magnetic Reissner-Nordstr\\"om metric free of any coordinate pathologies. The source fields comprising the model are all described by simple, well-behaved polynomial functions of the radial coordinate, and are combined with straightforward regularity conditions to yield expressions delimiting several fundamental physical parameters pertaining to this hypothetical astrophysical object.
M. Wakamatsu; H. Tsujimoto
2005-03-29
The theoretical predictions are given for the forward limit of the unpolarized spin-flip isovector generalized parton distribution function $(E^u - E^d)(x, \\xi, t)$ within the framework of the chiral quark soliton model, with full inclusion of the polarization of Dirac sea quarks. We observe that $[(H^u - H^d) + (E^u - E^d)](x,0,0)$ has a sharp peak around $x=0$, which we interpret as a signal of the importance of the pionic $q \\bar{q}$ excitation with large spatial extension in the transverse direction. Another interesting indication given by the predicted distribution in combination with Ji's angular momentum sum rule is that the $\\bar{d}$-quark carries more angular momentum than the $\\bar{u}$-quark in the proton, which may have some relation with the physics of the violation of the Gottfried sum rule.
ATMOSPHERIC CIRCULATION OF BROWN DWARFS: JETS, VORTICES, AND TIME VARIABILITY
Zhang, Xi; Showman, Adam P.
2014-06-10
A variety of observational evidence demonstrates that brown dwarfs exhibit active atmospheric circulations. In this study we use a shallow-water model to investigate the global atmospheric dynamics in the stratified layer overlying the convective zone on these rapidly rotating objects. We show that the existence and properties of the atmospheric circulation crucially depend on key parameters including the energy injection rate and radiative timescale. Under conditions of strong internal heat flux and weak radiative dissipation, a banded flow pattern comprised of east-west jet streams spontaneously emerges from the interaction of atmospheric turbulence with the planetary rotation. In contrast, when the internal heat flux is weak and/or radiative dissipation is strong, turbulence injected into the atmosphere damps before it can self-organize into jets, leading to a flow dominated by transient eddies and isotropic turbulence instead. The simulation results are not very sensitive to the form of the forcing. Based on the location of the transition between jet-dominated and eddy-dominated regimes, we suggest that many brown dwarfs may exhibit atmospheric circulations dominated by eddies and turbulence (rather than jets) due to the strong radiative damping on these worlds, but a jet structure is also possible under some realistic conditions. Our simulated light curves capture important features from observed infrared light curves of brown dwarfs, including amplitude variations of a few percent and shapes that fluctuate between single-peak and multi-peak structures. More broadly, our work shows that the shallow-water system provides a useful tool to illuminate fundamental aspects of the dynamics on these worlds.
The stability of the thermohaline circulation in global warming experiments
Schmittner, A.; Stocker, T.F.
1999-04-01
A simplified climate model of the coupled ocean-atmosphere system is used to perform extensive sensitivity studies concerning possible future climate change induced by anthropogenic greenhouse gas emissions. Supplemented with an active atmospheric hydrological cycle, experiments with different rates of CO{sub 2} increase and different climate sensitivities are performed. The model exhibits a threshold value of atmospheric CO{sub 2} concentration beyond which the North Atlantic Deep Water formation stops and never recovers. For a climate sensitivity that leads to an equilibrium warming of 3.6 C for a doubling of CO{sub 2} and a rate of CO{sub 2} increase of 1% yr{sup {minus}1}, the threshold lies between 650 and 700 ppmv. Moreover, it is shown that the stability of the thermohaline circulation depends on the rate of increase of greenhouse gases. For a slower increase of atmospheric pCO{sub 2} the final amount that can be reached without a shutdown of the circulation is considerably higher. This rate-sensitive response is due to the uptake of heat and excess freshwater from the uppermost layers to the deep ocean. The increased equator-to-pole freshwater transport in a warmer atmosphere is mainly responsible for the cessation of deep water formation in the North Atlantic. Another consequence of the enhanced latent heat transport is a stronger warming at high latitudes. A model version with fixed water vapor transport exhibits uniform warming at all latitudes. The inclusion of a simple parameterization of the ice-albedo feedback increases the model sensitivity and further decreases the pole-to-equator temperature difference in a greenhouse climate. The possible range of CO{sub 2} threshold concentrations and its dependency on the rate of CO{sub 2} increase, on the climate sensitivity, and on other model parameters are discussed.
Reducing mode circulating fluid bed combustion
Lin, Yung-Yi (Katy, TX); Sadhukhan, Pasupati (Katy, TX); Fraley, Lowell D. (Sugarland, TX); Hsiao, Keh-Hsien (Houston, TX)
1986-01-01
A method for combustion of sulfur-containing fuel in a circulating fluid bed combustion system wherein the fuel is burned in a primary combustion zone under reducing conditions and sulfur captured as alkaline sulfide. The reducing gas formed is oxidized to combustion gas which is then separated from solids containing alkaline sulfide. The separated solids are then oxidized and recycled to the primary combustion zone.
Heinemann, Detlev
IDENTIFICATION OF A GENERAL MODEL FOR THE MPP PERFORMANCE OF PV-MODULES FOR THE APPLICATION. ABSTRACT: To assure the maximal energy yield of grid connected PV systems, system faults have of this model for the application to grid connected PV systems using cSi, aSi and CIS modules is demonstrated. 1
Truong, Thanh N.
A general methodology for quantum modeling of free-energy profile of reactions in solution methodology for calculating free-energy profile of reaction in solution using quantum mechanical methods of molecules in solution, quantum model- ing of free-energy profile in solution still remains a challenge.1
The influence of the transition zone water filter on convective circulation in the mantle
The influence of the transition zone water filter on convective circulation in the mantle Garrett M 2004. [1] The ``transition zone water filter'' model of mantle convection attempts to reconcile bulk mass and heat transfer across mantle interfaces. Here we test the basic effect of the water filter
Sources of Variability in Gulf of Maine Circulation, and the Observations Needed to
Pringle, James "Jamie"
Sources of Variability in Gulf of Maine Circulation, and the Observations Needed to Model it. James in the Gulf of Maine are then quantified, with an emphasis on variability on timescales longer than tidal and the volume of water entering from the Scotian Shelf to the Gulf of Maine produce roughly comparable amounts
A numerical study of circulation and mixing in a macrotidal estuary: Cobscook Bay, Maine
Baca, Michael William
1998-01-01
A numerical, three-dimensional coastal ocean model was ics. used to study the circulation and subsequent mixing of Cobscook Bay by the lunar semi-diurnal tide. The results showed strong ebbing and flooding currents along a main channel connected...
Eocene circulation of the Southern Ocean: Was Antarctica kept warm by subtropical waters?
Döös, Kristofer
climate model simulations. We find that the EAC did not penetrate to high latitudes and ocean heatEocene circulation of the Southern Ocean: Was Antarctica kept warm by subtropical waters? Matthew suddenly grew and ocean productivity patterns changed. Previous studies conjectured that poleward
Raman, Sethu
(HIC) associated with an urban area can significantly alter lower tropospheric winds and lowObservations and Numerical Simulations of Urban Heat Island and Sea Breeze Circulations over New disaster on September 11, 2001. An ARPS model numerical simulation was conducted to explore the complex
TRANSPORT BY MERIDIONAL CIRCULATIONS IN SOLAR-TYPE STARS
Wood, T. S.; Brummell, N. H., E-mail: tsw25@soe.ucsc.edu [Department of Applied Mathematics and Statistics, Baskin School of Engineering, University of California Santa Cruz, CA (United States)
2012-08-20
Transport by meridional flows has significant consequences for stellar evolution, but is difficult to capture in global-scale numerical simulations because of the wide range of timescales involved. Stellar evolution models therefore usually adopt parameterizations for such transport based on idealized laminar or mean-field models. Unfortunately, recent attempts to model this transport in global simulations have produced results that are not consistent with any of these idealized models. In an effort to explain the discrepancies between global simulations and idealized models, here we use three-dimensional local Cartesian simulations of compressible convection to study the efficiency of transport by meridional flows below a convection zone in several parameter regimes of relevance to the Sun and solar-type stars. In these local simulations we are able to establish the correct ordering of dynamical timescales, although the separation of the timescales remains unrealistic. We find that, even though the generation of internal waves by convective overshoot produces a high degree of time dependence in the meridional flow field, the mean flow has the qualitative behavior predicted by laminar, 'balanced' models. In particular, we observe a progressive deepening, or 'burrowing', of the mean circulation if the local Eddington-Sweet timescale is shorter than the viscous diffusion timescale. Such burrowing is a robust prediction of laminar models in this parameter regime, but has never been observed in any previous numerical simulation. We argue that previous simulations therefore underestimate the transport by meridional flows.
THREE-DIMENSIONAL ATMOSPHERIC CIRCULATION OF HOT JUPITERS ON HIGHLY ECCENTRIC ORBITS
Kataria, T.; Showman, A. P.; Lewis, N. K. [Department of Planetary Sciences and Lunar and Planetary Laboratory, The University of Arizona, Tucson, AZ 85721 (United States)] [Department of Planetary Sciences and Lunar and Planetary Laboratory, The University of Arizona, Tucson, AZ 85721 (United States); Fortney, J. J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)] [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Marley, M. S.; Freedman, R. S., E-mail: tkataria@lpl.arizona.edu [NASA Ames Research Center 245-3, Moffett Field, CA 94035 (United States)
2013-04-10
Of the over 800 exoplanets detected to date, over half are on non-circular orbits, with eccentricities as high as 0.93. Such orbits lead to time-variable stellar heating, which has major implications for the planet's atmospheric dynamical regime. However, little is known about the fundamental dynamical regime of such planetary atmospheres, and how it may influence the observations of these planets. Therefore, we present a systematic study of hot Jupiters on highly eccentric orbits using the SPARC/MITgcm, a model which couples a three-dimensional general circulation model (the MITgcm) with a plane-parallel, two-stream, non-gray radiative transfer model. In our study, we vary the eccentricity and orbit-average stellar flux over a wide range. We demonstrate that the eccentric hot Jupiter regime is qualitatively similar to that of planets on circular orbits; the planets possess a superrotating equatorial jet and exhibit large day-night temperature variations. As in Showman and Polvani, we show that the day-night heating variations induce momentum fluxes equatorward to maintain the superrotating jet throughout its orbit. We find that as the eccentricity and/or stellar flux is increased (corresponding to shorter orbital periods), the superrotating jet strengthens and narrows, due to a smaller Rossby deformation radius. For a select number of model integrations, we generate full-orbit light curves and find that the timing of transit and secondary eclipse viewed from Earth with respect to periapse and apoapse can greatly affect what we see in infrared (IR) light curves; the peak in IR flux can lead or lag secondary eclipse depending on the geometry. For those planets that have large temperature differences from dayside to nightside and rapid rotation rates, we find that the light curves can exhibit 'ringing' as the planet's hottest region rotates in and out of view from Earth. These results can be used to explain future observations of eccentric transiting exoplanets.
T. P. Shestakova
2013-03-06
Among theoretical issues in General Relativity the problem of constructing its Hamiltonian formulation is still of interest. The most of attempts to quantize Gravity are based upon Dirac generalization of Hamiltonian dynamics for system with constraints. At the same time there exists another way to formulate Hamiltonian dynamics for constrained systems guided by the idea of extended phase space. We have already considered some features of this approach in the previous MG12 Meeting by the example of a simple isotropic model. Now we apply the approach to a generalized spherically symmetric model which imitates the structure of General Relativity much better. In particular, making use of a global BRST symmetry and the Noether theorem, we construct the BRST charge that generates correct gauge transformations for all gravitational degrees of freedom.
Wind induced circulation on the outer continental shelf of Texas, spring 1982
Beard, Daniel Walker
1984-01-01
in the record is offshore, to the southeast. On the 29th of March, in the wake of strong northeast winds, the current shifted to the west. In general, the westward direction was maintained throughout the deployment period. However, there was one occurrence... WIND INDUCED CIRCULATION ON THE OUTER CONTINENTAL SHELF OF TEXAS, SPRING 1982 A Thesis by DANIEL WALKER BEARD Submitted to the Graduate College of Texas AE M University in partial fulfillment of the requirements for the degree of MASTER...
Reversing the Circulation of Magnetic Vortices
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMassR&D100Nationalquestionnaires 0serial codesReversing the Circulation of Magnetic
Reversing the Circulation of Magnetic Vortices
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMassR&D100Nationalquestionnaires 0serial codesReversing the Circulation of
Reversing the Circulation of Magnetic Vortices
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMassR&D100Nationalquestionnaires 0serial codesReversing the Circulation ofReversing
Reversing the Circulation of Magnetic Vortices
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMassR&D100Nationalquestionnaires 0serial codesReversing the Circulation
Reversing the Circulation of Magnetic Vortices
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMassR&D100Nationalquestionnaires 0serial codesReversing the CirculationReversing
Carderock Circulating Water Channel | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX ECoopButte County,Camilla, Georgia: Energy ResourcesRanchCirculating Water Channel Jump
Hydrodynamic aspects of a circulating fluidized bed with internals
Balasubramanian, N.; Srinivasakannan, C.
1998-06-01
An attempt is made to examine the influence of internals (baffles) in the riser of the circulating fluidized bed. Experiments are conducted in a circulating fluidized bed, having perforated plates with different free areas. It is noticed from the present work that a circulating fluidized bed having 45% free area gives uniform solids concentration and pressure drop along the length of the riser. In addition to the uniformity, the circulating fluidized bed with internals gives higher pressure drop (solids concentration) compared to a conventional circulating fluidized bed. For internals having 67.6% free area the pressure drop is higher at the lower portion of the riser compared to the upper portion, similar to a conventional circulating fluidized bed. For 30% free area plates the solids concentration varies axially within the stage and remains uniform from stage to stage.
Rhode Island, University of
Impact of a Warm Ocean Eddy's Circulation on Hurricane-Induced Sea Surface Cooling with Implications for Hurricane Intensity RICHARD M. YABLONSKY AND ISAAC GINIS Graduate School of Oceanography) ABSTRACT Upper oceanic heat content (OHC) in advance of a hurricane is generally superior to prestorm sea
A PC simulation of heat transfer and temperature distribution in a circulating wellbore
Pierce, Robert Duane
1987-01-01
-Wold (Chair of Committee) James E. Russell (Member) Earl R. Hoskins (Member) D, Von Gonton (H ad of Department) December 1987 ABSTRACT A PC Simulation of Heat Transfer and Temperature Distribution in a Circulating Wellbore (December 1987) Robert... SUPPLEMENTAL SOURCES CONSULTED APPENDIX A: MATHEMATICAL MODEL AND TREATMENT 103 108 APPENDIX B: DERIVATION OF RAMEY'SS WELLBORE HEAT TRANSMISSION SOLUTION 112 APPENDIX C: RHEOLOGICAL PRESSURE LOSS MODEL CALCULATIONS APPENDIX D: OVER-ALL HEAT TRANSFER...
Progress in The Lost Circulation Technology Development Program
Glowka, D.A.; Schafer, D.M.; Loeppke, G.E.; Wright, E.K.
1991-01-01
Lost circulation is the loss of drilling fluid from the wellbore to fractures or pores in the rock formation. In geothermal drilling, lost circulation is often a serious problem that contributes greatly to the cost of the average geothermal well. The Lost Circulation Technology Development Program is sponsored at Sandia National Laboratories by the US Department of Energy. The goal of the program is to reduce lost circulation costs by 30--50{percent} through the development of mitigation and characterization technology. This paper describes the technical progress made in this program during the period April, 1990--March, 1991. 4 refs., 15 figs., 1 tab.
The Role of Circulation Features on Black Carbon Transport into...
Office of Scientific and Technical Information (OSTI)
significantly different AO modulation of BC transport over Northeast Asia and Eastern Europe. Nevertheless, we find that the overall climatological circulation patterns simulated...
Nairwita Mazumder; Subenoy Chakraborty
2010-05-19
In this letter, we investigate the validity of the generalized second law of thermodynamics of the universe bounded by the event horizon in the holographic dark energy model. The universe is chosen to be homogeneous and isotropic and the validity of the first law has been assumed here. The matter in the universe is taken in the form of non-interacting two fluid system- one component is the holographic dark energy model and the other component is in the form of dust.
Primary cementing across massive lost circulation zones
Turki, W.H.; Mackay, A.S.
1983-03-01
As a result of severe lost circulation problems in some wells in the Ghawar and Abqaiq Fields, Aramco has been unable to cover the Umm Er-Radhuma (Paleocene) and Wasia (Cretaceous) aquifers with cement. This has necessitated setting an extended liner opposite the Wasia aquifer, to ensure that there are two casing strings and a cement sheath across the aquifer, resulting in increased casing cost and reduced well productivity. This paper describes the results of field trial tests performed, along with conclusions and recommendations aimed at solving this problem. Field methods employed include light weight extended cements, ultra-light cement slurries weighing as little as 55 lbm/ft/sup 3/ (pcf), using ceramic hollow spheres, glass bubbles and foam, plus hydrostatic cementing, and mechanical devices. Finally, methods of job evaluation are discussed. These include temperature surveys, bond logs, radioactive tracers, and a new cement volume log.
Thermodynamics of atmospheric circulation on hot Jupiters
J. Goodman
2008-10-07
Atmospheric circulation on tidally-locked exoplanets is driven by the absorption and reradiation of heat from the host star. They are natural heat engines, converting heat into mechanical energy. A steady state is possible only if there is a mechanism to dissipate mechanical energy, or if the redistribution of heat is so effective that the Carnot efficiency is driven to zero. Simulations based on primitive, equivalent-barotropic, or shallow-water equations without explicit provision for dissipation of kinetic energy and for recovery of that energy as heat, violate energy conservation. More seriously perhaps, neglect of physical sources of drag may overestimate wind speeds and rates of advection of heat from the day to the night side.
Felice, Antonio De [TPTP and NEP, The Institute for Fundamental Study, Naresuan University, Phitsanulok 65000 (Thailand); Tsujikawa, Shinji, E-mail: antoniod@nu.ac.th, E-mail: shinji@rs.kagu.tus.ac.jp [Department of Physics, Faculty of Science, Tokyo University of Science, 1-3, Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan)
2012-02-01
In the Horndeski's most general scalar-tensor theories with second-order field equations, we derive the conditions for the avoidance of ghosts and Laplacian instabilities associated with scalar, tensor, and vector perturbations in the presence of two perfect fluids on the flat Friedmann-Lemaître-Robertson-Walker (FLRW) background. Our general results are useful for the construction of theoretically consistent models of dark energy. We apply our formulas to extended Galileon models in which a tracker solution with an equation of state smaller than -1 is present. We clarify the allowed parameter space in which the ghosts and Laplacian instabilities are absent and we numerically confirm that such models are indeed cosmologically viable.
Uncertainty quantification for large-scale ocean circulation predictions.
Safta, Cosmin; Debusschere, Bert J.; Najm, Habib N.; Sargsyan, Khachik
2010-09-01
Uncertainty quantificatio in climate models is challenged by the sparsity of the available climate data due to the high computational cost of the model runs. Another feature that prevents classical uncertainty analyses from being easily applicable is the bifurcative behavior in the climate data with respect to certain parameters. A typical example is the Meridional Overturning Circulation in the Atlantic Ocean. The maximum overturning stream function exhibits discontinuity across a curve in the space of two uncertain parameters, namely climate sensitivity and CO{sub 2} forcing. We develop a methodology that performs uncertainty quantificatio in the presence of limited data that have discontinuous character. Our approach is two-fold. First we detect the discontinuity location with a Bayesian inference, thus obtaining a probabilistic representation of the discontinuity curve location in presence of arbitrarily distributed input parameter values. Furthermore, we developed a spectral approach that relies on Polynomial Chaos (PC) expansions on each sides of the discontinuity curve leading to an averaged-PC representation of the forward model that allows efficient uncertainty quantification and propagation. The methodology is tested on synthetic examples of discontinuous data with adjustable sharpness and structure.
Van Gorder, Robert A.
2014-11-15
In R. A. Van Gorder, “General rotating quantum vortex filaments in the low-temperature Svistunov model of the local induction approximation,” Phys. Fluids 26, 065105 (2014) I discussed properties of generalized vortex filaments exhibiting purely rotational motion under the low-temperature Svistunov model of the local induction approximation. Such solutions are stationary in terms of translational motion. In the Comment [N. Hietala, “Comment on ‘General rotating quantum vortex filaments in the low-temperature Svistunov model of the local induction approximation’ [Phys. Fluids 26, 065105 (2014)],” Phys. Fluids 26, 119101 (2014)], the author criticizes my paper for not including translational motion (although it was clearly stated that the filament motion was assumed rotational). As it turns out, if one is interested in studying the geometric structure of solutions (which was the point of my paper), one obtains the needed qualitative results on the structure of such solutions by studying the purely rotational case. Nevertheless, in this Response I shall discuss the vortex filaments that have both rotational and translational motions. I then briefly discuss why one might want to study such generalized rotating filament solutions, in contrast to simple the standard helical or planar examples (which are really special cases). I also discuss how one can study the time evolution of filaments which exhibit more complicated dynamics than pure translation and rotation. Doing this, one can study non-stationary solutions which initially appear purely rotational and gradually display other dynamics as the filaments evolve.
Do Coupled Climate Models Correctly SImulate the Upward Branch of the Deept Ocean Global Conveyor?
Sarmiento, Jorge L; Downes, Stephanie; Bianchi, Daniele
2013-01-17
The large-scale meridional overturning circulation (MOC) connects the deep ocean, a major reservoir of carbon, to the other components of the climate system and must therefore be accurately represented in Earth System Models. Our project aims to address the specific question of the pathways and mechanisms controlling the upwelling branch of the MOC, a subject of significant disagreement between models and observational syntheses, and among general circulation models. Observations of these pathways are limited, particularly in regions of complex hydrography such as the Southern Ocean. As such, we rely on models to examine theories of the overturning circulation, both physically and biogeochemically. This grant focused on a particular aspect of the meridional overturning circulation (MOC) where there is currently significant disagreement between models and observationally based analyses of the MOC, and amongst general circulation models. In particular, the research focused on addressing the following questions: 1. Where does the deep water that sinks in the polar regions rise to the surface? 2. What processes are responsible for this rise? 3. Do state-of-the-art coupled GCMs capture these processes? Our research had three key components: observational synthesis, model development and model analysis. In this final report we outline the key results from these areas of research for the 2007 to 2012 grant period. The research described here was carried out primarily by graduate student, Daniele Bianchi (now a Postdoc at McGill University, Canada), and Postdoc Stephanie Downes (now a Research Fellow at The Australian national University, Australia). Additional support was provided for programmers Jennifer Simeon as well as Rick Slater.
Bill Jackson; Aldo Procacci; Alan D. Sokal
2014-12-02
We find zero-free regions in the complex plane at large |q| for the multivariate Tutte polynomial (also known in statistical mechanics as the Potts-model partition function) Z_G(q,w) of a graph G with general complex edge weights w = {w_e}. This generalizes a result of Sokal (cond-mat/9904146) that applies only within the complex antiferromagnetic regime |1+w_e| \\le 1. Our proof uses the polymer-gas representation of the multivariate Tutte polynomial together with the Penrose identity.
Estimates of the stratospheric residual circulation using the downward control principle
Rosenlof, K.H.; Holton, J.R. [Univ. of Washington, Seattle, WA (United States)
1993-06-20
The transformed Eulerian-mean momentum and continuity equations are used to calculate the residual mean meridional circulations for the lower stratosphere and troposphere. Momentum and temperature fluxes required for the computation are estimated from U.K. Meterological Office (UKMO) analyzed geopotential heights. National Center for Atmospheric Research (NCAR) CCM2 model output is used to assess the errors associated with the calculation. The model comparisons showed that the method works reasonably well for solstice seasons, but is inadequate for equinox seasons. In addition, it is found that some parameterization of gravity wave drag needs to be included with the planetary wave forcing to accurately estimate the residual mean circulation using this method. 24 refs., 10 figs., 5 tabs.
Ujjal Debnath; Surajit Chattopadhyay
2011-03-26
In this work, we have considered that the flat FRW universe is filled with the mixture of dark matter and the new holographic dark energy. If there is an interaction, we have investigated the natures of deceleration parameter, statefinder and $Om$ diagnostics. We have examined the validity of the first and generalized second laws of thermodynamics under these interactions on the event as well as apparent horizon. It has been observed that the first law is violated on the event horizon. However, the generalized second law is valid throughout the evolution of the universe enveloped by the apparent horizon. When the event horizon is considered as the enveloping horizon, the generalized second law is found to break down excepting at late stage of the universe.
Scarlat, Raluca Olga
2012-01-01
natural circulation solar water heater. Energy Conversionas water circulation in solar water heaters 60 , and passivewater circulation in solar water heaters 60 , and passive
Hietala, Niklas Hänninen, Risto
2014-11-15
Van Gorder considers a formulation of the local induction approximation, which allows the vortex to move in the direction of the reference axis [“General rotating quantum vortex filaments in the low-temperature Svistunov model of the local induction approximation,” Phys. Fluids 26, 065105 (2014)]. However, in his analytical and numerical study he does not use it. A mistake in the torsion of a helical vortex is also corrected.
The Role of Eddy-Tansport in the Thermohaline Circulation
Dr. Paola Cessi
2011-11-17
Several research themes were developed during the course of this project. (1) Low-frequency oceanic varibility; (2) The role of eddies in the Antarctic Circumpolar Current (ACC) region; (3) Deep stratification and the overturning circulation. The key findings were as follows: (1) The stratification below the main thermocline (at about 500m) is determined in the circumpolar region and then communicated to the enclosed portions of the oceans through the overturning circulation. (2) An Atlantic pole-to-pole overturning circulation can be maintained with very small interior mixing as long as surface buoyancy values are shared between the northern North Atlantic and the ACC region.
Does hydrologic circulation mask frictional heat on faults after large earthquakes?
Fulton, Patrick M.; Harris, Robert N.; Saffer, Demian M.; Brodsky, Emily E.
2010-01-01
from circulating fluids during drilling diffuse quickly5.1. Thermal Disturbance From Drilling Fluids [ 18 ]During drilling, fluids are circulated through the bore-
On the World-wide Circulation of the Deeper Waters of the World Ocean
Reid, Joseph L
2009-01-01
circulation of the Pacific Ocean: Flow patterns, tracers,in preparing the figures. Fig. 1 Pacific Ocean winds Fig.2 Pacific Ocean circulation Fig. 4 Pacific Ocean potential
Gilman, Lindsey Anne
2014-01-01
Advanced modeling capabilities were developed for application to subcooled flow boiling through this work. The target was to introduce, and demonstrate, all necessary mechanisms required to accurately predict the temperature ...
Gurgel, Angelo C.
We develop a forward-looking version of the MIT Emissions Prediction and Policy Analysis (EPPA) model, and apply it to examine the economic implications of proposals in the U.S. Congress to limit greenhouse gas (GHG) ...
Circulating heat exchangers for oscillating wave engines and refrigerators
Swift, Gregory W.; Backhaus, Scott N.
2003-10-28
An oscillating-wave engine or refrigerator having a regenerator or a stack in which oscillating flow of a working gas occurs in a direction defined by an axis of a trunk of the engine or refrigerator, incorporates an improved heat exchanger. First and second connections branch from the trunk at locations along the axis in selected proximity to one end of the regenerator or stack, where the trunk extends in two directions from the locations of the connections. A circulating heat exchanger loop is connected to the first and second connections. At least one fluidic diode within the circulating heat exchanger loop produces a superimposed steady flow component and oscillating flow component of the working gas within the circulating heat exchanger loop. A local process fluid is in thermal contact with an outside portion of the circulating heat exchanger loop.
Parameters of Integral Circulant Graphs and Periodic Quantum Dynamics
Nitin Saxena; Simone Severini; Igor Shparlinski
2007-03-26
The intention of the paper is to move a step towards a classification of network topologies that exhibit periodic quantum dynamics. We show that the evolution of a quantum system, whose hamiltonian is identical to the adjacency matrix of a circulant graph, is periodic if and only if all eigenvalues of the graph are integers (that is, the graph is integral). Motivated by this observation, we focus on relevant properties of integral circulant graphs. Specifically, we bound the number of vertices of integral circulant graphs in terms of their degree, characterize bipartiteness and give exact bounds for their diameter. Additionally, we prove that circulant graphs with odd order do not allow perfect state transfer.
Gas phase hydrodynamics inside a circulating fluidized bed
Moran, James C. (James Christopher)
2001-01-01
Circulating Fluidized Beds (CFB's) offer many advantages over traditional pulverized coal burners in the power generation industry. They operate at lower temperatures, have better environmental emissions and better fuel ...
Isentropic diagnostics of mid-latitude circulation and transport
Koh, Tieh-Yong, 1972-
2001-01-01
This thesis examines the mid-latitude circulation and tracer transport using zonal average isentropic diagnostics. The Underworld (i.e. the region roughly below the 300K-isentrope) is targeted by our research. Currently, ...
Coppola, Laurent
Thorium isotopes as tracers of particles dynamics and deep water circulation in the Indian sector to study the distribution of thorium isotopes (234 Th, 232 Th and 230 Th) in the water column of the Indian in surface water (0100 m) and a model was applied to estimate a residence time relative to the thorium
Kim, Who Myung
2013-05-02
warming. Yet, a variety source of observations and its assimilation into ocean circulation models have not supported such an AMOC decline so far. In this study, an aspect that has not been paid attention, regarding the maintenance of the AMOC strength...
Ganguly, A. E-mail: aganguly@maths.iitkgp.ernet.in; Das, A.
2014-11-15
We consider one-dimensional stationary position-dependent effective mass quantum model and derive a generalized Korteweg-de Vries (KdV) equation in (1+1) dimension through Lax pair formulation, one being the effective mass Schrödinger operator and the other being the time-evolution of wave functions. We obtain an infinite number of conserved quantities for the generated nonlinear equation and explicitly show that the new generalized KdV equation is an integrable system. Inverse scattering transform method is applied to obtain general solution of the nonlinear equation, and then N-soliton solution is derived for reflectionless potentials. Finally, a special choice has been made for the variable mass function to get mass-deformed soliton solution. The influence of position and time-dependence of mass and also of the different representations of kinetic energy operator on the nature of such solitons is investigated in detail. The remarkable features of such solitons are demonstrated in several interesting figures and are contrasted with the conventional KdV-soliton associated with constant-mass quantum model.
Integration of Different Wave Forcing Formulations with Nearshore Circulation Models
Sharma, Abhishek
2012-02-14
chaotic pattern of set-up/down and current field in the regions where the wave field is not purely progressive. The third approach ignores the effect of wave diffraction and reflection, and primarily simulates the effect of energy dissipation. Differences...
Zakirjon Kanokov; Juern W. P. Schmelzer; Avazbek K. Nasirov
2009-04-07
An analysis of a variety of existing experimental data leads to the conclusion on the existence of a resonance mechanism allowing weak magnetic fields to affect biological processes. These fields may either be static magnetic fields comparable in magnitude with the magnetic field of the earth or weak ultra-low frequency time-dependent fields. So far, a generally accepted theoretical model allowing one to understand the effect of magnetic and electric fields on biological processes is not available. By this reason, it is not clear which characteristics of the fields, like magnetic and electric field strength, frequency of change of the field, shape of the electromagnetic wave, the duration of the magnetic or electric influence or some particular combination of them, are responsible for the biological effect. In the present analysis it is shown that external time-independent magnetic fields may cause a resonance amplification of ionic electric currents in biological tissues and, in particular, in the vasculature system due to a Brownian motion of charges. These resonance electric currents may cause necrotic changes in the tissues or blood circulation and in this way significantly affect the biological organism. The magnitude of the magnetic fields leading to resonance effects is estimated, it is shown that it depends significantly on the radius of the blood capillaries.
Yang, Zhaoqing; Khangaonkar, Tarang
2010-11-19
Water circulation in Puget Sound, a large complex estuary system in the Pacific Northwest coastal ocean of the United States, is governed by multiple spatially and temporally varying forcings from tides, atmosphere (wind, heating/cooling, precipitation/evaporation, pressure), and river inflows. In addition, the hydrodynamic response is affected strongly by geomorphic features, such as fjord-like bathymetry and complex shoreline features, resulting in many distinguishing characteristics in its main and sub-basins. To better understand the details of circulation features in Puget Sound and to assist with proposed nearshore restoration actions for improving water quality and the ecological health of Puget Sound, a high-resolution (around 50 m in estuaries and tide flats) hydrodynamic model for the entire Puget Sound was needed. Here, a threedimensional circulation model of Puget Sound using an unstructured-grid finite volume coastal ocean model is presented. The model was constructed with sufficient resolution in the nearshore region to address the complex coastline, multi-tidal channels, and tide flats. Model open boundaries were extended to the entrance of the Strait of Juan de Fuca and the northern end of the Strait of Georgia to account for the influences of ocean water intrusion from the Strait of Juan de Fuca and the Fraser River plume from the Strait of Georgia, respectively. Comparisons of model results, observed data, and associated error statistics for tidal elevation, velocity, temperature, and salinity indicate that the model is capable of simulating the general circulation patterns on the scale of a large estuarine system as well as detailed hydrodynamics in the nearshore tide flats. Tidal characteristics, temperature/salinity stratification, mean circulation, and river plumes in estuaries with tide flats are discussed.
elimination capacity and on the rate of biomass growth were considered. Using model simulations, the influence-scale biotrickling filters have been installed for air treatment [4-7]. The main obstacle for the deployment time. Existing large biotrickling filters have therefore mostly been deployed for applications with low
Ezer,Tal
-order turbulence closure scheme that provides surface and BBL mixing and results in a quite re- alistic climatology-following grid. However, with the same turbulence scheme but using a z-level grid, the model was unable in the two grids is due to the larger vertical mixing generated by the turbulence scheme over the step
Nagurney, Anna
Supply Chain Performance Assessment and Supplier and Component Importance Identification competitive supply chain network game theory model, which includes the supplier tier. The firms components from one or more suppliers, who also are capacitated. The firms compete in a Cournot-Nash fashion
Simulation of NOx emission in circulating fluidized beds burning low-grade fuels
Afsin Gungor
2009-05-15
Nitrogen oxides are a major environmental pollutant resulting from combustion. This paper presents a modeling study of pollutant NOx emission resulting from low-grade fuel combustion in a circulating fluidized bed. The simulation model accounts for the axial and radial distribution of NOx emission in a circulating fluidized bed (CFB). The model results are compared with and validated against experimental data both for small-size and industrial-size CFBs that use different types of low-grade fuels given in the literature. The present study proves that CFB combustion demonstrated by both experimental data and model predictions produces low and acceptable levels of NOx emissions resulting from the combustion of low-grade fuels. Developed model can also investigate the effects of different operational parameters on overall NOx emission. As a result of this investigation, both experimental data and model predictions show that NOx emission increases with the bed temperature but decreases with excess air if other parameters are kept unchanged. 37 refs., 5 figs., 5 tabs.
Colbert, J.J.; Sheehan, K.A.
1995-08-16
This document describes the structure, organization, and mathematical formulations for the Stand-Damage Model and the Biological basis for these formulations. Growth, mortality, and regeneration are modeled along with the effects of user-prescribed defoliation and stand-management actions. The appendices provide a full description of the logic and mathematics in the form of code listings, structure charts, and files.
Optimization Under Generalized Uncertainty
Lodwick, Weldon
11 Optimization Under Generalized Uncertainty Optimization Modeling Math 4794/5794: Spring 2013 Weldon A. Lodwick Weldon.Lodwick@ucdenver.edu 2/14/2013 Optimization Modeling - Spring 2013 #12 in the context of optimization problems. The theoretical frame-work for these notes is interval analysis. From
Broader source: Energy.gov [DOE]
This position may be located in either the Office of Energy Statistics or the Office of Energy Analysis of EIA. This position is established to provide a professional general engineer to perform...
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Van Gorder, Robert A.
2014-06-15
In his study of superfluid turbulence in the low-temperature limit, Svistunov [“Superfluid turbulence in the low-temperature limit,” Phys. Rev. B 52, 3647 (1995)] derived a Hamiltonian equation for the self-induced motion of a vortex filament. Under the local induction approximation (LIA), the Svistunov formulation is equivalent to a nonlinear dispersive partial differential equation. In this paper, we consider a family of rotating vortex filament solutions for the LIA reduction of the Svistunov formulation, which we refer to as the 2D LIA (since it permits a potential formulation in terms of two of the three Cartesian coordinates). This class of solutions holds the well-known Hasimoto-type planar vortex filament [H. Hasimoto, “Motion of a vortex filament and its relation to elastica,” J. Phys. Soc. Jpn. 31, 293 (1971)] as one reduction and helical solutions as another. More generally, we obtain solutions which are periodic in the space variable. A systematic analytical study of the behavior of such solutions is carried out. In the case where vortex filaments have small deviations from the axis of rotation, closed analytical forms of the filament solutions are given. A variety of numerical simulations are provided to demonstrate the wide range of rotating filament behaviors possible. Doing so, we are able to determine a number of vortex filament structures not previously studied. We find that the solution structure progresses from planar to helical, and then to more intricate and complex filament structures, possibly indicating the onset of superfluid turbulence.
Basement Structure and Implications for Hydrothermal Circulation...
than along the axis of a single dike. Gravity modeling and subsurface data from deep geothermal wells indicate that the floor of the caldera is segmented into a number of...
images from 2011 and 2012 to define the near-global distribution of zonal winds and eddy momentum fluxes combined with the greater feature contrast in the northern hemisphere during the approach to spring equinox allow for better rejection of erroneous wind vectors, a more objective assessment at any latitude
O'Gorman, Paul
20052006). Dates of radiosonde changes (red dotted lines) are one sort of `metadata event',5 others--change of pressure sensor; triangle--change of wind equipment; square--change of relative humidity sensor. Photos
Canuto, V
2015-01-01
This is an English translation of the Italian version of an encyclopedia chapter that appeared in the Italian Encyclopedia of the Physical Sciences, edited by Bruno Bertotti (1994). Following requests from colleagues we have decided to make it available to a more general readership. We present the motivation for constructing General Relativity, provide a short discussion of tensor algebra, and follow the set up of Einstein equations. We discuss briefly the initial value problem, the linear approximation and how should non gravitational physics be described in curved spacetime.
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Recent progress on Exxon's circulating zinc bromine battery system
Bellows, R.J.
1981-01-01
The design, performance, and factory cost of Exxon's circulating zinc bromine batteries are described. The Exxon system has demonstrated stable performance in scale-ups to 3- and 10-kWh sub-modules. Cost studies based on recently demonstrated extrusion and injection molding techniques, have shown that this battery, with plastic electrodes, bipolar stacks, Br/sub 2/ complexation, and circulating electrolytes, could be produced (20 kWh units, 100,000 units/year) at a factory cost of $28/kWh (excluding R.O.I., and various indirect overheads).
Sponaugle, Su
model using a mesoscale-resolving ocean general circulation model (OGCM). Al- though the simulationsare
Amy Honchar
2012-11-12
The contribution of funds from DOE supported publication costs of a special issue of Deep Sea Research arising from presentations at the First U.S. Atlantic Meridional Overturning Circulation (AMOC) Meeting held 4-6 May, 2009 to review the US implementation plan and its coordination with other monitoring activities. The special issue includes a total of 16 papers, including publications from three DOE-supported investigators (ie Sevellec, F., and A.V. Fedorov; Hu et. al., and Wan et. al.,). The special issue addresses DOE interests in understanding and simulation/modeling of abrupt climate change.
Decadal variability of the Atlantic Meridional Overturning Circulation
Buckley, Martha Weaver
2011-01-01
In the mean, the Atlantic Ocean transports 1 to 1.5 PW of heat northward, and estimates suggest that 60% of this heat transport is associated with a circulation that reaches the cold waters of the abyss. Due to the role ...
Pandoe, Wahyu Widodo
2004-09-30
provides a basis for determining how the water circulation three-dimensionally controls the hydrodynamics of the system and ultimately transports the suspended and soluble materials due to combined currents and waves. A three-dimensional circulation model...
Benchmarking assessment of RELAP5/MOD3 for the low flow and natural circulation experiment
Martin, R.P. (EG and G Idaho, Inc., Idaho Falls, ID (United States)); Taylor, B.K. (Westinghouse Savannah River Co., Aiken, SC (United States))
1992-01-01
The RELAP5/MOD3 code was assessed against experimental thermal hydraulics data for a 12.5 foot test section comprised of two vertical concentric tubes with water flowing upward in the tubes. The inner tubewas stainless steel and uniformly heated. ne outer tube was transparent polycarbonate (lexan) and unheated. The experimental procedure incorporated a test matrix of 24 tests to address single- and two-phase flow, forced and natural circulation flow and heated and unheated fluid. The tests were conducted at system pressures of 14.7 and 17.0 psia. Nine of the tests representing the full range of test conditions were analyzed using RELAP5/MOD3. RELAP5/MOD3 analysis of the tests yielded general agreement with experiment with regard to the prediction of forced flow and natural circulation trends. However, a number of deficiencies were observed in the RELAP5/MOD3 treatment and these, along with recommendations for their resolution, are described in the paper.
Benchmarking assessment of RELAP5/MOD3 for the low flow and natural circulation experiment
Martin, R.P. [EG and G Idaho, Inc., Idaho Falls, ID (United States); Taylor, B.K. [Westinghouse Savannah River Co., Aiken, SC (United States)
1992-11-01
The RELAP5/MOD3 code was assessed against experimental thermal hydraulics data for a 12.5 foot test section comprised of two vertical concentric tubes with water flowing upward in the tubes. The inner tubewas stainless steel and uniformly heated. ne outer tube was transparent polycarbonate (lexan) and unheated. The experimental procedure incorporated a test matrix of 24 tests to address single- and two-phase flow, forced and natural circulation flow and heated and unheated fluid. The tests were conducted at system pressures of 14.7 and 17.0 psia. Nine of the tests representing the full range of test conditions were analyzed using RELAP5/MOD3. RELAP5/MOD3 analysis of the tests yielded general agreement with experiment with regard to the prediction of forced flow and natural circulation trends. However, a number of deficiencies were observed in the RELAP5/MOD3 treatment and these, along with recommendations for their resolution, are described in the paper.
The circulation of the ocean is usually divided into two parts, a wind-driven circulation that
measurements show that the thermohaline circulation turns over all the deep water in the ocean every 600 years, in the formation of new deep water in the North Atlantic and the Southern Ocean. Large volumes of cold polar water occurs and how upwelled deep water returns to the areas of deep-water formation. The main new development
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DRILLING MACHINES GENERAL INFORMATION
Gellman, Andrew J.
TC 9-524 Chapter 4 DRILLING MACHINES GENERAL INFORMATION PURPOSE This chapter contains basic information pertaining to drilling machines. A drilling machine comes in many shapes and sizes, from small hand-held power drills to bench mounted and finally floor-mounted models. They can perform operations
Traditional and novel approaches to palaeoclimate modelling
Crucifix, Michel
2012-01-01
Palaeoclimate archives contain information on climate variability, trends and mechanisms. Models are developed to explain observations and predict the response of the climate system to perturbations, in particular perturbations associated with the anthropogenic influence. Here, we review three classical frameworks of climate modelling: conceptual, simulator-based (including general circulation models and Earth system models of intermediate complexity), and statistical. The conceptual framework aims at a parsimonious representation of a given climate phenomenon; the simulator-based framework connects physical and biogeochemical principles with phenomena at different spatial and temporal scales; and statistical modelling is a framework for inference from observations, given hypotheses on systematic and random effects. Recently, solutions have been proposed in the literature to combine these frameworks, and new concepts have emerged: the emulator (a statistical, computing efficient surrogate for the simulator) a...
MFIX simulation of NETL/PSRI challenge problem of circulating fluidized bed
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Li, Tingwen; Dietiker, Jean-François; Shahnam, Mehrdad
2012-12-01
In this paper, numerical simulations of NETL/PSRI challenge problem of circulating fluidized bed (CFB) using the open-source code Multiphase Flow with Interphase eXchange (MFIX) are reported. Two rounds of simulation results are reported including the first-round blind test and the second-round modeling refinement. Three-dimensional high fidelity simulations are conducted to model a 12-inch diameter pilot-scale CFB riser. Detailed comparisons between numerical results and experimental data are made with respect to axial pressure gradient profile, radial profiles of solids velocity and solids mass flux along different radial directions at various elevations for operating conditions covering different fluidization regimes. Overall, the numericalmore »results show that CFD can predict the complex gas–solids flow behavior in the CFB riser reasonably well. In addition, lessons learnt from modeling this challenge problem are presented.« less
MFIX simulation of NETL/PSRI challenge problem of circulating fluidized bed
Li, Tingwen; Dietiker, Jean-François; Shahnam, Mehrdad
2012-12-01
In this paper, numerical simulations of NETL/PSRI challenge problem of circulating fluidized bed (CFB) using the open-source code Multiphase Flow with Interphase eXchange (MFIX) are reported. Two rounds of simulation results are reported including the first-round blind test and the second-round modeling refinement. Three-dimensional high fidelity simulations are conducted to model a 12-inch diameter pilot-scale CFB riser. Detailed comparisons between numerical results and experimental data are made with respect to axial pressure gradient profile, radial profiles of solids velocity and solids mass flux along different radial directions at various elevations for operating conditions covering different fluidization regimes. Overall, the numerical results show that CFD can predict the complex gas–solids flow behavior in the CFB riser reasonably well. In addition, lessons learnt from modeling this challenge problem are presented.
Joan Sola; David Lopez-Val
2011-07-07
We present an updated overview on the phenomenology of one-loop Higgs boson production at Linear Colliders within the general Two-Higgs-Doublet Model (2HDM). First we report on the Higgs boson pair production, and associated Higgs-Z boson production, at O(alpha^3_{ew}) from e+e- collisions. These channels furnish cross-sections in the range of 10-100 fb for Ecm=0.5 TeV and exhibit potentially large radiative corrections (of order 50%), whose origin can be traced back to the genuine enhancement capabilities of the triple Higgs boson self-interactions. Next we consider the loop-induced production of a single Higgs boson from direct gamma-gamma scattering. We single out sizable departures from the corresponding rates in the Standard Model, which are again correlated to trademark dynamical features of the 2HDM -- namely the balance of the non-standard Higgs/gauge, Higgs/fermion and Higgs self-interactions leading to sizable (destructive) interference effects. This pattern of quantum effects is unmatched in the MSSM, and could hence provide distinctive footprints of non-supersymmetric Higgs boson physics. Both calculations are revisited within a common, brought-to-date framework and include, in particular, the most stringent bounds from unitarity and flavor physics.
Experimental Study of the Circulation Air Volume of Recirculation Evaporative Cooling
Xiong, J.; Liu, Z.; Wang, C.; Chen, G.
2006-01-01
This paper introduces the technology of re-circulation evaporative cooling (REC), which uses a portion of supply air as secondary air to make cool water used to indirectly cool outside air through a heat exchanger. The circulation volume...
A self-circulating heat exchanger for use in stirling andthermoacoust...
Office of Scientific and Technical Information (OSTI)
Conference: A self-circulating heat exchanger for use in stirling and thermoacoustic-stirling engines Citation Details In-Document Search Title: A self-circulating heat exchanger...
Marshall, John C.
A series of coupled atmosphere–ocean–ice aquaplanet experiments is described in which topological constraints on ocean circulation are introduced to study the role of ocean circulation on the mean climate of the coupled ...
The effect of a hydraulic parameterisation of overflows on the ocean circulation
Born, Andreas
eine Bistabilit¨at erm¨oglichen. #12;Contents 1 Introduction 7 2 The circulation in the Atlantic Ocean
Mueller, Bernhard; Janka, Hans-Thomas; Marek, Andreas, E-mail: bjmuellr@mpa-garching.mpg.de, E-mail: thj@mpa-garching.mpg.de [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany)
2012-09-01
We present the first two-dimensional general relativistic (GR) simulations of stellar core collapse and explosion with the COCONUT hydrodynamics code in combination with the VERTEX solver for energy-dependent, three-flavor neutrino transport, using the extended conformal flatness condition for approximating the space-time metric and a ray-by-ray-plus ansatz to tackle the multi-dimensionality of the transport. For both of the investigated 11.2 and 15 M{sub Sun} progenitors we obtain successful, though seemingly marginal, neutrino-driven supernova explosions. This outcome and the time evolution of the models basically agree with results previously obtained with the PROMETHEUS hydro solver including an approximative treatment of relativistic effects by a modified Newtonian potential. However, GR models exhibit subtle differences in the neutrinospheric conditions compared with Newtonian and pseudo-Newtonian simulations. These differences lead to significantly higher luminosities and mean energies of the radiated electron neutrinos and antineutrinos and therefore to larger energy-deposition rates and heating efficiencies in the gain layer with favorable consequences for strong nonradial mass motions and ultimately for an explosion. Moreover, energy transfer to the stellar medium around the neutrinospheres through nucleon recoil in scattering reactions of heavy-lepton neutrinos also enhances the mentioned effects. Together with previous pseudo-Newtonian models, the presented relativistic calculations suggest that the treatment of gravity and energy-exchanging neutrino interactions can make differences of even 50%-100% in some quantities and is likely to contribute to a finally successful explosion mechanism on no minor level than hydrodynamical differences between different dimensions.
Environmental Impact and Sustainability Applied General Equilibrium...
Model (ENVISAGE) Jump to: navigation, search Tool Summary LAUNCH TOOL Name: Environmental Impact and Sustainability Applied General Equilibrium Model (ENVISAGE) Agency...
Parametric study of natural circulation flow in molten salt fuel in molten salt reactor
Pauzi, Anas Muhamad; Cioncolini, Andrea; Iacovides, Hector
2015-04-29
The Molten Salt Reactor (MSR) is one of the most promising system proposed by Generation IV Forum (GIF) for future nuclear reactor systems. Advantages of the MSR are significantly larger compared to other reactor system, and is mainly achieved from its liquid nature of fuel and coolant. Further improvement to this system, which is a natural circulating molten fuel salt inside its tube in the reactor core is proposed, to achieve advantages of reducing and simplifying the MSR design proposed by GIF. Thermal hydraulic analysis on the proposed system was completed using a commercial computation fluid dynamics (CFD) software called FLUENT by ANSYS Inc. An understanding on theory behind this unique natural circulation flow inside the tube caused by fission heat generated in molten fuel salt and tube cooling was briefly introduced. Currently, no commercial CFD software could perfectly simulate natural circulation flow, hence, modeling this flow problem in FLUENT is introduced and analyzed to obtain best simulation results. Results obtained demonstrate the existence of periodical transient nature of flow problem, hence improvements in tube design is proposed based on the analysis on temperature and velocity profile. Results show that the proposed system could operate at up to 750MW core power, given that turbulence are enhanced throughout flow region, and precise molten fuel salt physical properties could be defined. At the request of the authors and the Proceedings Editor the name of the co-author Andrea Cioncolini was corrected from Andrea Coincolini. The same name correction was made in the Acknowledgement section on page 030004-10 and in reference number 4. The updated article was published on 11 May 2015.
Dependence of heat transport on the strength and shear rate of prescribed circulating flows
Emily S. C. Ching; K. M. Pang
2001-11-28
We study numerically the dependence of heat transport on the maximum velocity and shear rate of physical circulating flows, which are prescribed to have the key characteristics of the large-scale mean flow observed in turbulent convection. When the side-boundary thermal layer is thinner than the viscous boundary layer, the Nusselt number (Nu), which measures the heat transport, scales with the normalized shear rate to an exponent 1/3. On the other hand, when the side-boundary thermal layer is thicker, the dependence of Nu on the Peclet number, which measures the maximum velocity, or the normalized shear rate when the viscous boundary layer thickness is fixed, is generally not a power law. Scaling behavior is obtained only in an asymptotic regime. The relevance of our results to the problem of heat transport in turbulent convection is also discussed.
Polymer grouts for plugging lost circulation in geothermal wells.
Galbreath, D. (Green Mountain International, Waynesvile, NC); Mansure, Arthur James; Bauer, Stephen J.
2004-12-01
We have concluded a laboratory study to evaluate the survival potential of polymeric materials used for lost circulation plugs in geothermal wells. We learned early in the study that these materials were susceptible to hydrolysis. Through a systematic program in which many potential chemical combinations were evaluated, polymers were developed which tolerated hydrolysis for eight weeks at 500 F. The polymers also met material, handling, cost, and emplacement criteria. This screening process identified the most promising materials. A benefit of this work is that the components of the polymers developed can be mixed at the surface and pumped downhole through a single hose. Further strength testing is required to determine precisely the maximum temperature at which extrusion through fractures or voids causes failure of the lost circulation plug.
On the circulation and stratification of the Weddell Gyre
Orsi, Alejandro H.
1990-01-01
, and probably also in deep water formation over the continental margins of the eastern sector. Within the ACC the upper portion of the CDW is characterized by a temperature maximum (8-max) and oxygen minimum (~-min). The lower part of the CDW (LCDW... on selected isopycnals. South of the eastward-flowing Antarctic Circumpolar Current, the Weddell Gyre is revealed as a weakly-sheared circulation elongated in the southwest-to-northeast direction. Southward penetration of Circumpolar Deep Water (CDW...
Circulant conference matrices for new complex Hadamard matrices
Petre Dita
2011-07-07
The circulant real and complex matrices are used to find new real and complex conference matrices. With them we construct Sylvester inverse orthogonal matrices by doubling the size of inverse complex conference matrices. When the free parameters take values on the unit circle the inverse orthogonal matrices transform into complex Hadamard matrices. The method is used for $n=6$ conference matrices and in this way we find new parametrisations of Hadamard matrices for dimension $ n=12$.
A toolkit for building earth system models
Foster, I.
1993-03-01
An earth system model is a computer code designed to simulate the interrelated processes that determine the earth's weather and climate, such as atmospheric circulation, atmospheric physics, atmospheric chemistry, oceanic circulation, and biosphere. I propose a toolkit that would support a modular, or object-oriented, approach to the implementation of such models.
A toolkit for building earth system models
Foster, I.
1993-03-01
An earth system model is a computer code designed to simulate the interrelated processes that determine the earth`s weather and climate, such as atmospheric circulation, atmospheric physics, atmospheric chemistry, oceanic circulation, and biosphere. I propose a toolkit that would support a modular, or object-oriented, approach to the implementation of such models.
Gidaspow, D.; Ettehadieh, B.; Lin, C.; Goyal, A.; Lyczkowski, R.W.
1980-01-01
The object of this investigation was to develop an experimentally verified hydrodynamic model to predict solids circulation around a jet in a fluidized bed gasifier. Hydrodynamic models of fluidization use the principles of conservation of mass, momentum and energy. To account for unequal velocities of solid and fluid phases, separate phase momentum balances are developed. Other fluid bed models used in the scale-up of gasifiers do not employ the principles of conservation of momentum. Therefore, these models cannot predict fluid and particle motion. In such models solids mixing is described by means of empirical transfer coefficients. A two dimensional unsteady state computer code was developed to give gas and solid velocities, void fractions and pressure in a fluid bed with a jet. The growth, propagation and collapse of bubbles was calculated. Time-averaged void fractions were calculated that showed an agreement with void fractions measured with a gamma ray densitometer. Calculated gas and solid velocities in the jet appeared to be reasonable. Pressure and void oscillations also appear to be reasonable. A simple analytical formula for the rate of solids circulation was developed from the equations of change. It agrees with Westinghouse fluidization data in a bed with a draft tube. One dimensional hydrodynamic models were applied to modeling of entrained-flow coal gasification reactors and compared with data. Further development of the hydrodynamic models should make the scale-up and simulation of fluidized bed reactors a reality.
Fedorov, Alexey
2013-11-23
The central goal of this research project is to understand the properties of the ocean meridional overturning circulation (MOC) – a topic critical for understanding climate variability and stability on a variety of timescales (from decadal to centennial and longer). Specifically, we have explored various factors that control the MOC stability and decadal variability in the Atlantic and the ocean thermal structure in general, including the possibility abrupt climate change. We have also continued efforts on improving the performance of coupled ocean-atmosphere GCMs.
Follows, Mick
Impact of circulation on export production, dissolved organic matter, and dissolved oxygen; published 8 August 2007. [1] Results are presented of export production, dissolved organic matter (DOM ± 6 Pg C yrÀ1 . Model means of globally averaged particle export, the fraction of total export
Constrained Generalized Supersymmetries
Toppan, Francesco; Kuznetsova, Zhanna
2005-10-17
We present a classification of admissible types of constraint (hermitian, holomorphic, with reality condition on the bosonic sectors, etc.) for generalized supersymmetries in the presence of complex spinors. A generalized supersymmetry algebra involving n-component real spinors Qa is given by the anticommutators {l_brace}Q{sub a},Q{sub b}{r_brace} = Z{sub ab} where the matrix Z appearing in the r.h.s. is the most general symmetric matrix. A complex generalized supersymmetry algebra is expressed in terms of complex spinors Qa and their complex conjugate Q* a. The most general (with a saturated r.h.s.) algebra is in this case given by {l_brace}Q{sub a},Q{sub b}{r_brace} P{sub ab}{l_brace}Q*{sub a}, Q*{sub b}{r_brace} = P*{sub ab}{l_brace}Q{sub a},Q*{sub b}{r_brace} = R{sub ab} where the matrix Pab is symmetric, while Rab is hermitian. The bosonic right hand side can be expressed in terms of the rank-k totally antisymmetric tensors P{sub ab} {sigma}k(C{gamma}{sub [{mu}}{sub 1...{mu}}{sub k]}){sub ab}P{sup [{mu}{sup 1...{mu}{sup k}]}.The decomposition in terms of anti-symmetric tensors for any space-time up to dimension D = 13 is presented. Real type, complex type, and quaternionic type space-times are classified. Any restriction on the saturated bosonic generators that allows all possible combinations of these tensors is in principle admissible by a Lorenz-covariant requirement. We investigate division algebra constraints and their influence on physical models. High spin theory models are presented as examples of the applications of such models.
HTGR-SC/C program baseline review meeting, Session IIC: circulators, C and I, and helium service
Not Available
1981-01-01
Information is presented concerning main and auxiliary circulators; reactor service equipment; and control and instrumentation systems.
Regional Climate Modeling: Progress, Challenges, and Prospects
Wang, Yuqing; Leung, Lai R.; McGregor, John L.; Lee, Dong-Kyou; Wang, Wei-Chyung; Ding, Yihui; Kimura, Fujio
2004-12-01
Regional climate modeling with regional climate models (RCMs) has matured over the past decade and allows for meaningful utilization in a broad spectrum of applications. In this paper, latest progresses in regional climate modeling studies are reviewed, including RCM development, applications of RCMs to dynamical downscaling for climate change assessment, seasonal climate predictions and climate process studies, and the study of regional climate predictability. Challenges and potential directions of future research in this important area are discussed, with the focus on those to which less attention has been given previously, such as the importance of ensemble simulations, further development and improvement of regional climate modeling approach, modeling extreme climate events and sub-daily variation of clouds and precipitation, model evaluation and diagnostics, applications of RCMs to climate process studies and seasonal predictions, and development of regional earth system models. It is believed that with both the demonstrated credibility of RCMs’ capability in reproducing not only monthly to seasonal mean climate and interannual variability but also the extreme climate events when driven by good quality reanalysis and the continuous improvements in the skill of global general circulation models (GCMs) in simulating large-scale atmospheric circulation, regional climate modeling will remain an important dynamical downscaling tool for providing the needed information for assessing climate change impacts and seasonal climate predictions, and a powerful tool for improving our understanding of regional climate processes. An internationally coordinated effort can be developed with different focuses by different groups to advance regional climate modeling studies. It is also recognized that since the final quality of the results from nested RCMs depends in part on the realism of the large-scale forcing provided by GCMs, the reduction of errors and improvement in physics parameterizations in both GCMs and RCMs remain a priority for climate modeling community.
Global Circulating Fluidized Bed Boilers Market | OpenEI Community
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QAsource History View New PagesSustainable UrbanKentucky:BoreOpenGilliamOhio: EnergyGlenwillow,Iowa:BusCirculating
Absolute Continuous Bivariate Generalized Exponential Distribution
Kundu, Debasis
Absolute Continuous Bivariate Generalized Exponential Distribution Debasis Kundu and Rameshwar D. Gupta Abstract Generalized exponential distribution has been used quite effectively to model posi- tively skewed lifetime data as an alternative to the well known Weibull or gamma distributions
Wang, Zhengyuan
Intestinal stem cells play a pivotal role in the epithelial tissue renewal, homeostasis and cancer development. The lack of a general marker for intestinal stem cells across species has hampered analysis of stem cell number ...
Intermediate- to Deep-Water Circulation Changes on Short and Long Time Scales
Murphy, Daniel Patrick
2012-07-16
. Deborah Thomas Oceanic circulation remains one of the poorly understood elements of the global climate system, despite its importance to planetary heat redistribution and carbon cycling. The nature of deep-water formation and circulation in ancient... oceans are even more poorly constrained. In order to understand climate dynamics of past and future climates we must have a better understanding of the role of deep-ocean circulation. In this dissertation I investigated changes in intermediate...
Massingill, Robert Derryl, Jr.
2006-04-12
, efforts have been focused on developing new Lost Circulation Materials (LCM?s) that are more effective and that minimize the operation costs by achieving sufficient FCS to allow drilling to continue.7,8 A variety of products have been proposed with a... chemical lost circulation treatments have emerged that focus on rapid application and effectively widening the mud weight window, therefore, minimizing drilling costs. Among the most popular LCM?s used while treating minor lost circulations are blended...
General Relativistic Radiative Transfer
S. Knop; P. H. Hauschildt; E. Baron
2006-11-30
We present a general method to calculate radiative transfer including scattering in the continuum as well as in lines in spherically symmetric systems that are influenced by the effects of general relativity (GR). We utilize a comoving wavelength ansatz that allows to resolve spectral lines throughout the atmosphere. The used numerical solution is an operator splitting (OS) technique that uses a characteristic formal solution. The bending of photon paths and the wavelength shifts due to the effects of GR are fully taken into account, as is the treatment of image generation in a curved spacetime. We describe the algorithm we use and demonstrate the effects of GR on the radiative transport of a two level atom line in a neutron star like atmosphere for various combinations of continuous and line scattering coefficients. In addition, we present grey continuum models and discuss the effects of different scattering albedos on the emergent spectra and the determination of effective temperatures and radii of neutron star atmospheres.
Atmospheric circulation of eccentric hot Jupiter HAT-P-2B
Lewis, Nikole K.; Showman, Adam P.; Fortney, Jonathan J.; Knutson, Heather A.; Marley, Mark S.
2014-11-10
The hot Jupiter HAT-P-2b has become a prime target for Spitzer Space Telescope observations aimed at understanding the atmospheric response of exoplanets on highly eccentric orbits. Here we present a suite of three-dimensional atmospheric circulation models for HAT-P-2b that investigate the effects of assumed atmospheric composition and rotation rate on global scale winds and thermal patterns. We compare and contrast atmospheric models for HAT-P-2b, which assume one and five times solar metallicity, both with and without TiO/VO as atmospheric constituents. Additionally we compare models that assume a rotation period of half, one, and two times the nominal pseudo-synchronous rotation period. We find that changes in assumed atmospheric metallicity and rotation rate do not significantly affect model predictions of the planetary flux as a function of orbital phase. However, models in which TiO/VO are present in the atmosphere develop a transient temperature inversion between the transit and secondary eclipse events that results in significant variations in the timing and magnitude of the peak of the planetary flux compared with models in which TiO/VO are omitted from the opacity tables. We find that no one single atmospheric model can reproduce the recently observed full orbit phase curves at 3.6, 4.5 and 8.0 ?m, which is likely due to a chemical process not captured by our current atmospheric models for HAT-P-2b. Further modeling and observational efforts focused on understanding the chemistry of HAT-P-2b's atmosphere are needed and could provide key insights into the interplay between radiative, dynamical, and chemical processes in a wide range of exoplanet atmospheres.
Interacting new generalized Chaplygin gas
Mubasher Jamil
2009-10-20
We have presented a model in which the new generalized Chaplygin gas interacts with matter. We find that there exists a stable scaling solution at late times in the evolution of the universe. Moreover, the phantom crossing scenario is observed in this model.
Generalized Dirac operators and superconnections
G. Roepstorff; Ch. Vehns
1999-11-04
Motivated by the supersymmetric version of Dirac's theory, chiral models in field theory, and the quest of a geometric fundament for the Standard Model, we describe an approach to the differential geometry of vector bundles on (semi)-Riemannian manifolds based on the concepts of superspaces, superalgebras, superconnections, and generalized Dirac operators. In doing so we stay within the realm of commutative geometry.
The Low-Energy State of Circulating Stored Ion Beams: Crystalline Beams
Wei, J.
2008-01-01
Proc. of the Workshop on Crystalline Ion Beams, Werheim,Critical Temperatures for Crystalline Beams", Proc. of theCirculating Stored Ion Beams: Crystalline Beams J. Wei, X. -
Intermediate-depth circulation of the Indian and South Pacific Oceans measured by autonomous floats
Davis, Russ E
2005-01-01
circulation of the Pacific Ocean: Flow patterns, tracers,the Indian and South Pacific Oceans Measured by Autonomousthe tropical and South Pacific Ocean and 228 were deployed
Estimating the solar meridional circulation by normal mode decomposition
Lars Krieger; Markus Roth; Oskar von der Luehe
2008-11-05
The objective of this article is to use Fourier-Hankel decomposition as suggested earlier by Braun & Fan (1998) to estimate the integrated horizontal meridional flow velocity as a function of mode penetration depth, and to find ways of potentially improve this technique. We use a time series of 43200 (30 days) consecutive full-disk Dopplergrams obtained by the MDI (Michelson Doppler Imager) instrument aboard the SOHO (Solar Heliospheric Observatory) spacecraft in April 1999. We find averaged meridional flow estimates of 15 m/s for modes with a penetration depth in the upper 20 Mm of the solar convection zone. This reproduces the results of the earlier investigations. Moreover we conclude that this method has the potential to become a new technique to measure the meridional circulation in the deep convection zone, if some improvements will be applied.
Options for Cryogenic Load Cooling with Forced Flow Helium Circulation
Peter Knudsen, Venkatarao Ganni, Roberto Than
2012-06-01
Cryogenic pumps designed to circulate super-critical helium are commonly deemed necessary in many super-conducting magnet and other cooling applications. Acknowledging that these pumps are often located at the coldest temperature levels, their use introduces risks associated with the reliability of additional rotating machinery and an additional load on the refrigeration system. However, as it has been successfully demonstrated, this objective can be accomplished without using these pumps by the refrigeration system, resulting in lower system input power and improved reliability to the overall cryogenic system operations. In this paper we examine some trade-offs between using these pumps vs. using the refrigeration system directly with examples of processes that have used these concepts successfully and eliminated using such pumps
Doppler Signatures of the Atmospheric Circulation on Hot Jupiters
Showman, Adam P; Lewis, Nikole K; Shabram, Megan
2013-01-01
The meteorology of hot Jupiters has been characterized primarily with thermal measurements, but recent observations suggest the possibility of directly detecting the winds by observing the Doppler shift of spectral lines seen during transit. Motivated by these observations, we show how Doppler measurements can place powerful constraints on the meteorology. We show that the atmospheric circulation--and Doppler signature--of hot Jupiters splits into two regimes. Under weak stellar insolation, the day-night thermal forcing generates fast zonal jet streams from the interaction of atmospheric waves with the mean flow. In this regime, air along the terminator (as seen during transit) flows toward Earth in some regions and away from Earth in others, leading to a Doppler signature exhibiting superposed blue- and redshifted components. Under intense stellar insolation, however, the strong thermal forcing damps these planetary-scale waves, inhibiting their ability to generate jets. Strong frictional drag likewise damps...
Bozeman, Jeffrey; Chen, Kuo-Huey
2014-12-09
On November 3, 2009, General Motors (GM) accepted U.S. Department of Energy (DOE) Cooperative Agreement award number DE-EE0000014 from the National Energy Technology Laboratory (NETL). GM was selected to execute a three-year cost shared research and development project on Solid State Energy Conversion for Vehicular Heating, Ventilation & Air Conditioning (HVAC) and for Waste Heat Recovery.
Computer support to run models of the atmosphere. Final report
Fung, I.
1996-08-30
This research is focused on a better quantification of the variations in CO{sub 2} exchanges between the atmosphere and biosphere and the factors responsible for these exchangers. The principal approach is to infer the variations in the exchanges from variations in the atmospheric CO{sub 2} distribution. The principal tool involves using a global three-dimensional tracer transport model to advect and convect CO{sub 2} in the atmosphere. The tracer model the authors used was developed at the Goddard institute for Space Studies (GISS) and is derived from the GISS atmospheric general circulation model. A special run of the GCM is made to save high-frequency winds and mixing statistics for the tracer model.
Aerosol specification in single-column Community Atmosphere Model version 5
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Lebassi-Habtezion, B.; Caldwell, P. M.
2015-03-27
Single-column model (SCM) capability is an important tool for general circulation model development. In this study, the SCM mode of version 5 of the Community Atmosphere Model (CAM5) is shown to handle aerosol initialization and advection improperly, resulting in aerosol, cloud-droplet, and ice crystal concentrations which are typically much lower than observed or simulated by CAM5 in global mode. This deficiency has a major impact on stratiform cloud simulations but has little impact on convective case studies because aerosol is currently not used by CAM5 convective schemes and convective cases are typically longer in duration (so initialization is less important).more »By imposing fixed aerosol or cloud-droplet and crystal number concentrations, the aerosol issues described above can be avoided. Sensitivity studies using these idealizations suggest that the Meyers et al. (1992) ice nucleation scheme prevents mixed-phase cloud from existing by producing too many ice crystals. Microphysics is shown to strongly deplete cloud water in stratiform cases, indicating problems with sequential splitting in CAM5 and the need for careful interpretation of output from sequentially split climate models. Droplet concentration in the general circulation model (GCM) version of CAM5 is also shown to be far too low (~ 25 cm?3) at the southern Great Plains (SGP) Atmospheric Radiation Measurement (ARM) site.« less
Author's personal copy Sensitivity of the Atlantic Ocean circulation to a hydraulic overflow
Levermann, Anders
Author's personal copy Sensitivity of the Atlantic Ocean circulation to a hydraulic overflow the explicit representation of the overflows using a parameterisation by hydraulic constraints and compare circulation (AMOC) (Redler and Böning, 1997; Kuhlbrodt et al., 2007). The potential energy stored in the dense
Control of the ocean circulation by boundaries and topography P.B. Rhines
energy in the ocean circulation is dominated by boundary currents, zonal jets and mesoscale eddies and jet-like zonal currents dominate the kinetic energy of the world ocean. They are key features of bothControl of the ocean circulation by boundaries and topography P.B. Rhines University of Washington
1 Drivers of the projected changes to the Pacific Ocean 2 equatorial circulation
Paris-Sud XI, Université de
1 Drivers of the projected changes to the Pacific Ocean 2 equatorial circulation 3 A. Sen Gupta,1 A), 29 Drivers of the projected changes to the Pacific Ocean equatorial 30 circulation, Geophys. Res. Lett., 39, LXXXXX, doi:10.1029/ 31 2012GL051447. 32 1. Introduction 33 [2] The equatorial Pacific Ocean
Mesoscale circulations and atmospheric CO2 variations in the Tapajos Region, Para, Brazil
Collett Jr., Jeffrey L.
Mesoscale circulations and atmospheric CO2 variations in the Tapajo´s Region, Para´, Brazil Lixin; published 2 November 2005. [1] We have investigated mesoscale circulations and atmospheric CO2 variations over a heterogeneous landscape of forests, pastures, and large rivers during the Santare´m Mesoscale
Sensitivity of the Overturning Circulation in the Southern Ocean to Decadal Changes in Wind Forcing
Naveira Garabato, Alberto
Sensitivity of the Overturning Circulation in the Southern Ocean to Decadal Changes in Wind Forcing circulation in the Southern Ocean to the recent decadal strengthening of the overlying winds is being to changes in winds. Fundamental to reconciling these diverse views is to un- derstand properly the role
On the role of topography and wind stress on the stability of the thermohaline circulation
Edwards, Neil
On the role of topography and wind stress on the stability of the thermohaline circulation Neil R or absence of wind stress. If the ow exhibits collapses we consider how topography and wind stress a ect the circulation by modifying the barotropic ow and reducing the depth of convection. Wind stress stabilizes
Thomas, Debbie
circulation in a greenhouse world Deborah J. Thomas and Mitchell Lyle Department of Oceanography, Texas A Ocean likely exerted the greatest marine influence on climate during the greenhouse interval and implications for thermohaline circulation in a greenhouse world, Geochem. Geophys. Geosyst., 9, Q02002, doi:10
Circulation during intermittent lung ventilation in the ~artel" snake Thamnophis WARREN B URG(;RFS
Burggren, Warren
I .'11 Circulation during intermittent lung ventilation in the ~artel" snake Thamnophis WARREN B" Vi'lllW5 Received April 26, 1'177 RU\\lung "/-'r1t relationship, within the central arterial circulation ",'ere observed during intermittent. voluntary lung
Wind- and Buoyancy-modulated Along-shore Circulation over the Texas-Louisiana Shelf
Zhang, Zhaoru
2013-07-22
Numerical experiments are used to study the wind- and buoyancy-modulated along-shore circulation over the Texas-Louisiana continental shelf inshore of 50-m water depth. Most attention is given to circulation in the non-summer flow regime. A major...
Leenaarts, J.; Pereira, T. M. D.; Carlsson, M.; De Pontieu, B. [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern, N-0315 Oslo (Norway); Uitenbroek, H., E-mail: jorritl@astro.uio.no, E-mail: tiago.pereira@astro.uio.no, E-mail: mats.carlsson@astro.uio.no, E-mail: bdp@lmsal.com, E-mail: huitenbroek@nso.edu [NSO/Sacramento Peak, P.O. Box 62, Sunspot, NM 88349-0062 (United States)
2013-08-01
NASA's Interface Region Imaging Spectrograph (IRIS) space mission will study how the solar atmosphere is energized. IRIS contains an imaging spectrograph that covers the Mg II h and k lines as well as a slit-jaw imager centered at Mg II k. Understanding the observations will require forward modeling of Mg II h and k line formation from three-dimensional (3D) radiation-MHD models. This paper is the first in a series where we undertake this forward modeling. We discuss the atomic physics pertinent to h and k line formation, present a quintessential model atom that can be used in radiative transfer computations, and discuss the effect of partial redistribution (PRD) and 3D radiative transfer on the emergent line profiles. We conclude that Mg II h and k can be modeled accurately with a four-level plus continuum Mg II model atom. Ideally radiative transfer computations should be done in 3D including PRD effects. In practice this is currently not possible. A reasonable compromise is to use one-dimensional PRD computations to model the line profile up to and including the central emission peaks, and use 3D transfer assuming complete redistribution to model the central depression.
Determining root causes of drilling problems by combining cases and general knowledge
Aamodt, Agnar
-based, knowledge intensive, oil well drilling 1 Introduction Drilling of oil wells is an expensive offshore based reasoning to improve efficiency of oil well drilling. Their focus was on lost circulation, whichDetermining root causes of drilling problems by combining cases and general knowledge Samad
Quantum Mechanics and the Generalized Uncertainty Principle
Jang Young Bang; Micheal S. Berger
2006-11-30
The generalized uncertainty principle has been described as a general consequence of incorporating a minimal length from a theory of quantum gravity. We consider a simple quantum mechanical model where the operator corresponding to position has discrete eigenvalues and show how the generalized uncertainty principle results for minimum uncertainty wave packets.
Bivariate Generalized Exponential Distribution
Kundu, Debasis
Bivariate Generalized Exponential Distribution Debasis Kundu and Rameshwar D. Gupta Abstract Recently it is observed that the generalized exponential distribution can be used quite effectively exponential distribution so that the marginals have generalized exponential distributions. It is observed
Lauderdale, Jonathan M.
The effect of idealized wind-driven circulation changes in the Southern Ocean on atmospheric CO[subscript 2] and the ocean carbon inventory is investigated using a suite of coarse-resolution, global coupled ocean circulation ...
Artificial general intelligence: an organism and level based position
Smith, Leslie S.
Artificial general intelligence: an organism and level based position statement Leslie S. SMITH 1. Keywords. artificial general intelligence, brain model, paramecium, level interaction Introduction There are many views of what should be described as artificial general intelligence. Gen- eral intelligence
Monge, Juan
2012-10-19
The economic impacts of a government-funded, forest-based sequestration program were analyzed under two different payment schemes. The impacts were obtained by developing a regional, static CGE model built to accommodate a modified IMPLAN SAM for a...
Khangaonkar, Tarang; Wang, Taiping
2013-01-02
Circulation in typical fjords is characterized by a shallow brackish layer at the surface over a deep long and narrow saltwater column. This surface layer is responsible for the outflow of water from the fjord, is easily disrupted by external forces, such as wind, and is influenced by freshwater inflow. In this paper, we postulate that the stability of fjordal circulation may also be vulnerable to impacts from anthropogenic alterations, such as floating structures, that could constrict the mixing and transport in the upper layers of the water column. The potential for alteration of circulation in Hood Canal, a silled-fjord located inside Puget Sound, Washington, has been examined. Using classical analytical treatments along the lines formulated by Hansen and Rattray [1965], Rattray [1967], Dyer [1973] and more recently, MacCready [2004], we develop a solution applicable to a range of estuary classifications varying from a partially mixed estuary regime to classical fjord conditions. Both estuary types exist in the Puget Sound system, and we compare our analytical solution with observed data. The analysis is based on an exponential variation of eddy viscosity with depth, and it has been extended further with modifications of the free surface boundary conditions to develop a solution representing the presence of a floating bridge at the estuary/fjord entrance. The model results show that tidally averaged mean circulation under the influence of such a constraint could reduce by as much as 30 to 50 percent. The overall water quality of fjords and narrow estuaries is dependent on net circulation and flushing. A potential decrease in residual flow or a corresponding increase in residence time of this magnitude merits further study.
Technical report: Multivariate generalized S-estimators
Van Aelst, Stefan
Technical report: Multivariate generalized S-estimators Roelant E. a, Van Aelst S. a Croux C. b a-estimators for the multivariate regression model. This class of estimators combines high robustness and high efficiency of residuals. In the special case of a multivariate location model, the generalized S-estimator has
Newton, James Edward
1982-01-01
calculat1on y1elded a I ground. state conf1gurat1on in which the bonding orbital has an occu- pation number of 1. 97 and the antibond1ng orbital has an occupat1on number of 0. 03 electrons. Both Pauling and Griffith geometr1es of Nn(0 )(H C H ) y1... Geometries. Basis sets. . Results Fenske-Hall molecular orbi tal calculations. Restricted Hartree-Fock-Roothaan-Configuration Interaction calculations. 56 58 59 ~ ~ 59 ~ ~ 61 62 62 65 Generalized Molecular Orbi tal-Conf i gurati on Interaction...
A cryogenic circulating advective multi-pass absorption cell
Stockett, M. H.; Lawler, J. E. [Department of Physics, University of Wisconsin, 1150 University Avenue, Madison, Wisconsin 53706 (United States)
2012-03-15
A novel absorption cell has been developed to enable a spectroscopic survey of a broad range of polycyclic aromatic hydrocarbons (PAH) under astrophysically relevant conditions and utilizing a synchrotron radiation continuum to test the still controversial hypothesis that these molecules or their ions could be carriers of the diffuse interstellar bands. The cryogenic circulating advective multi-pass absorption cell resembles a wind tunnel; molecules evaporated from a crucible or injected using a custom gas feedthrough are entrained in a laminar flow of cryogenically cooled buffer gas and advected into the path of the synchrotron beam. This system includes a multi-pass optical White cell enabling absorption path lengths of hundreds of meters and a detection sensitivity to molecular densities on the order of 10{sup 7} cm{sup -3}. A capacitively coupled radio frequency dielectric barrier discharge provides ionized and metastable buffer gas atoms for ionizing the candidate molecules via charge exchange and the Penning effect. Stronger than expected clustering of PAH molecules has slowed efforts to record gas phase PAH spectra at cryogenic temperatures, though such clusters may play a role in other interstellar phenomena.
Circulating fluidized-bed boiler makes inroads for waste recycling
1995-09-01
Circulating fluidized-bed (CFB) boilers have ben used for years in Scandinavia to burn refuse-derived fuel (RDF). Now, Foster Wheeler Power Systems, Inc., (Clinton, N.J.) is bringing the technology to the US. Touted as the world`s largest waste-to-energy plant to use CFB technology, the Robbins (III.) Resource Recovery Facility will have the capacity to process 1,600 tons/d of municipal solid waste (MSW) when it begins operation in early 1997. The facility will have two materials-separation and RDF-processing trains, each with dual trommel screens, magnetic and eddy current separators, and shredders. About 25% of the incoming MSW will be sorted and removed for recycling, while 75% of it will be turned into fuel, with a heat value of roughly 6,170 btu/lb. Once burned in the twin CFB boilers the resulting steam will be routed through a single turbine generator to produce 50,000 mW of electric power.
Modeling pCO sub 2 in the upper ocean
Archer, D.
1990-12-01
This report summarizes our current understanding of the physical, chemical, and biological processes that control the natural cycling of carbon dioxide (CO{sub 2}) in the surface ocean. Because the physics of mixing at the ocean surface creates the essential framework for the chemistry and biology, and because the literature on surface ocean mixing is extensive, a major focus of the report is to review existing mixed layer models for the upper ocean and their implementation in global ocean circulation models. Three families of mixed layer models have been developed. The integrated turbulent kinetic energy'' (TKE) models construct a budget for surface ocean TKE, using the wind stress as source and dissipation as sink for TKE. The shear instability'' models maintain profiles of current velocity resulting from the wind stress. Turbulence closure'' models are the most general and the most complicated of the three types, and are based on laboratory studies of fluid turbulence. This paper explores behavioral distinctions between the three types of models, and summarizes previously published comparisons of the generality, accuracy, and computational requirements of the three models. The application of mixed layer models to treatment of sea ice is also reviewed. 101 refs., 7 figs., 1 tab.
Wind Turbine Blockset General Overview
Wind Turbine Blockset in Saber General Overview and Description of the Models Florin Iov, Adrian Turbine Blockset in Saber Abstract. This report presents a new developed Saber Toolbox for wind turbine, optimize and design wind turbines". The report provides a quick overview of the Saber and then explains
-encounter-Bethe BEB model in which a simple expression for the optical-oscillator strength, based on the results from H, He, and H2, is employed in the ex- pression of the Bethe cross section. Both the BED and BEB
Gildor, Hezi
an ecological system that includes coral reefs and other tropical biota that are unique in such high latitudes importance and the severe anthropogenic stresses that endanger the gulf and may alter it permanently
QUANTUM MECHANICS, GENERAL PHYSICS; 74 ATOMIC AND MOLECULAR PHYSICS...
Office of Scientific and Technical Information (OSTI)
of model atoms in fields Milonni, P.W. 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 74 ATOMIC AND MOLECULAR PHYSICS; ATOMS; OPTICAL MODELS; QUANTUM MECHANICS;...
Polarized 3He Gas Circulating Technologies for Neutron Analyzers
Watt, David; Hersman, Bill
2014-12-10
We describe the development of an integrated system for quasi-continuous operation of a large volume neutron analyzer. The system consists of a non-magnetic diaphragm compressor, a prototype large volume helium polarizer, a surrogate neutron analyzer, a non-depolarizing gas storage reservoir, a non-ferrous valve manifold for handling gas distribution, a custom rubidium-vapor gas return purifier, and wire-wound transfer lines, all of which are immersed in a two-meter external magnetic field. Over the Phase II period we focused on three major tasks required for the successful deployment of these types of systems: 1) design and implementation of gas handling hardware, 2) automation for long-term operation, and 3) improvements in polarizer performance, specifically fabrication of aluminosilicate optical pumping cells. In this report we describe the design, implementation, and testing of the gas handling hardware. We describe improved polarizer performance resulting from improved cell materials and fabrication methods. These improvements yielded valved 8.5 liter cells with relaxation times greater than 12 hours. Pumping this cell with 1500W laser power with 1.25nm linewidth yielded peak polarizations of 60%, measured both inside and outside the polarizer. Fully narrowing this laser to 0.25nm, demonstrated separately on one stack of the four, would have allowed 70% polarization with this cell. We demonstrated the removal of 5 liters of polarized helium from the polarizer with no measured loss of polarization. We circulated the gas through a titanium-clad compressor with polarization loss below 3% per pass. We also prepared for the next phase of development by refining the design of the polarizer so that it can be engineer-certified for pressurized operation. The performance of our system far exceeds comparable efforts elsewhere.
Inference for Model Error Allan Seheult
Oakley, Jeremy
Reservoirs, Model Error, Reification, Thermohaline Circulation. 1 Introduction Mathematical models of complex that the uncertainties associated with both calibrating a mathematical model to observations on a physical system specification exercise of model error with the cosmologists, linked to an extensive analysis of model
The Full Water Disposal Ways and Study on Central Air-conditioning Circulation Cooling Water System
Zhang, J.
2006-01-01
This paper has been made the further study about the water quality issue of the central air-conditioning circulation cooling water. Based on the comparison of the existing common adopted disposal ways, put forward the new ways of combination...
The role of the geothermal heat flux in driving the abyssal ocean circulation
Mashayek, A.
The results presented in this paper demonstrate that the geothermal heat flux (GHF) from the solid Earth into the ocean plays a non-negligible role in determining both abyssal stratification and circulation strength. Based ...
Slip stream apparatus and method for treating water in a circulating water system
Cleveland, J.R.
1997-03-18
An apparatus is described for treating water in a circulating water system that has a cooling water basin which includes a slip stream conduit in flow communication with the circulating water system, a source of acid solution in flow communication with the slip stream conduit, and a decarbonator in flow communication with the slip stream conduit and the cooling water basin. In use, a slip stream of circulating water is drawn from the circulating water system into the slip stream conduit of the apparatus. The slip stream pH is lowered by contact with an acid solution provided from the source thereof. The slip stream is then passed through a decarbonator to form a treated slip stream, and the treated slip stream is returned to the cooling water basin. 4 figs.
Sensitivity of the Ocean's Meridional Overturning Circulation to Surface Conditions in the Paleogene
Haines, Brian Andrew
2012-10-19
Deep circulations in the ocean affect the distribution of physical, chemical, and biological properties, and are intimately entwined with the planetary-scale climate. Numerous proxies, including neodymium (Nd) in fossil fish teeth, point to a source...
Li, Xiaochang, S.M. Massachusetts Institute of Technology
2009-01-01
It is commonly accepted that media and communication technologies play pivotal roles in the complex processes of what is broadly termed "globalization." The increasing speed, volume, and scale of transnational circulation ...
Mayers, Jared R.
Most patients with pancreatic ductal adenocarcinoma (PDAC) are diagnosed with advanced disease and survive less than 12 months. PDAC has been linked with obesity and glucose intolerance, but whether changes in circulating ...
Armour, Kyle C.
We propose here that the Atlantic meridional overturning circulation (AMOC) plays an important role in setting the effective heat capacity of the World Ocean and thus impacts the pace of transient climate change. The depth ...
Stability analysis of natural circulation in BWRs at high pressure conditions
Hu, Rui, Ph. D. Massachusetts Institute of Technology
2007-01-01
At rated conditions, a natural circulation boiling water reactor (NCBWR) depends completely on buoyancy to remove heat from the reactor core. This raises the issue of potential unstable flow. oscillations. The objective ...
Telomere Length in Circulating Leukocytes Is Associated with Lung Function and Disease
Nyholt, Dale R.
Telomere Length in Circulating Leukocytes Is Associated with Lung Function and Disease Eva Albrecht. Comprehensive Pneumology Center Munich (CPC-M), Member of the German Center for Lung Research, Munich, Germany
Kaminski, Edouard
Porous compaction in transient creep regime and implications for melt, petroleum, and CO2 in transient creep regime and implications for melt, petroleum, and CO2 circulation, J. Geophys. Res., 113, B
Evolution of Atlantic deep-water circulation: from the greenhouse to the icehouse
Via, Rachael Kathleen
2005-11-01
To better understand how the evolution of Cenozoic deep-water circulation related to changes in global climate and ocean basin configuration, we generated Nd isotope records from Ocean Drilling Program sites in the southeastern Atlantic to track...
Slip stream apparatus and method for treating water in a circulating water system
Cleveland, Joe R. (West Hills, CA)
1997-01-01
An apparatus (10) for treating water in a circulating water system (12) t has a cooling water basin (14) includes a slip stream conduit (16) in flow communication with the circulating water system (12), a source (36) of acid solution in flow communication with the slip stream conduit (16), and a decarbonator (58) in flow communication with the slip stream conduit (16) and the cooling water basin (14). In use, a slip stream of circulating water is drawn from the circulating water system (12) into the slip stream conduit (16) of the apparatus (10). The slip stream pH is lowered by contact with an acid solution provided from the source (36) thereof. The slip stream is then passed through a decarbonator (58) to form a treated slip stream, and the treated slip stream is returned to the cooling water basin (14).
CaltechWater January 27, 2006 The Global Circulation of
Roca, Rémy
. Despite advances in computer power, energy balance models and their some- what embellished cousins for determining whether key processes operate in the same way in models as in the real world become brighter
Bed-inventory Overturn Mechanism for Pant-leg Circulating Fluidized Bed Boilers
Wang, Zhe; Yang, Zhiwei; West, Logan; Li, Zheng
2011-01-01
A numerical model was established to investigate the lateral mass transfer as well as the mechanism of bed-inventory overturn inside a pant-leg circulating fluidized bed (CFB), which are of great importance to maintain safe and efficient operation of the CFB. Results show that the special flow structure in which the solid particle volume fraction along the central line of the pant-leg CFB is relative high enlarges the lateral mass transfer rate and make it more possible for bed inventory overturn. Although the lateral pressure difference generated from lateral mass transfer inhibits continuing lateral mass transfer, providing the pant-leg CFB with self-balancing ability to some extent, the primary flow rate change due to the outlet pressure change often disable the self-balancing ability by continually enhancing the flow rate difference. As the flow rate of the primary air fan is more sensitive to its outlet pressure, it is easier to lead to bed inventory overturn. While when the solid particle is easier to c...
Experimental study of the hydrodynamics and cluster formation in a Circulating Fluidized Bed
Gautam, M.; Johnson, E.
1991-01-01
A novel non-invasive gas-solid flow measuring technique being developed and tested for studying the hydrodynamics inside the riser of a Circulating Fluidized Bed (CFB). First of the two aims of the overall program, namely, design, development and testing of the technique to characterize the particle and gas velocities in two-phase flows was accomplished in the past year. The fringe-model'' laser Doppler anemometry concept has been modified and extended by using particles coated with a fluorescent dye and introducing a narrow band pass filter in the receiving optics. The technique permits optical discrimination between the scattered light (laser wavelength from undyed particles) and the fluorescence emission (longer wavelength). Results from extensive testing of various dye-solvent combinations, counter processor settings, signal-to noise optimization and subsequent flow measurements in the test section have shown that the technique can effectively discriminate between two classes of particles--the smaller seed particles for the gas phase data and the larger bed particles. Use of a two-watt Argon-Ion laser assisted in the non-intrusive probing of the gas-solid flow and in enhancing the signal-to-noise ratio. An uncertainty analysis of LDA measurements is presented. Design of the cold flow CFB model, presently under fabrication, is outlined in this report. The Plexiglas CFB model will be employed for the riser core-annular flow studies using the fluorescence-emission based laser-Doppler anemometry. The results from this study will present a unique detailed description of the complex gas-solid behavior in the CFB riser.
Evaluation of equipment and methods to map lost circulation zones in geothermal wells
McDonald, W.J.; Leon, P.A.; Pittard, G.
1981-05-01
A study and evaluation of methods to locate, characterize, and quantify lost circulation zones are described. Twenty-five methods of mapping and quantifying lost circulation zones were evaluated, including electrical, acoustical, mechanical, radioactive, and optical systems. Each tool studied is described. The structured, numerical evaluation plan, used as the basis for comparing the 25 tools, and the resulting ranking among the tools is presented.
The generalized Schrödinger–Langevin equation
Bargueño, Pedro; Miret-Artés, Salvador
2014-07-15
In this work, for a Brownian particle interacting with a heat bath, we derive a generalization of the so-called Schrödinger–Langevin or Kostin equation. This generalization is based on a nonlinear interaction model providing a state-dependent dissipation process exhibiting multiplicative noise. Two straightforward applications to the measurement process are then analyzed, continuous and weak measurements in terms of the quantum Bohmian trajectory formalism. Finally, it is also shown that the generalized uncertainty principle, which appears in some approaches to quantum gravity, can be expressed in terms of this generalized equation. -- Highlights: •We generalize the Kostin equation for arbitrary system–bath coupling. •This generalization is developed both in the Schrödinger and Bohmian formalisms. •We write the generalized Kostin equation for two measurement problems. •We reformulate the generalized uncertainty principle in terms of this equation.
Use of Advanced Meteorological Model Output for Coastal Ocean Modeling in Puget Sound
Yang, Zhaoqing; Khangaonkar, Tarang; Wang, Taiping
2011-06-01
It is a great challenge to specify meteorological forcing in estuarine and coastal circulation modeling using observed data because of the lack of complete datasets. As a result of this limitation, water temperature is often not simulated in estuarine and coastal modeling, with the assumption that density-induced currents are generally dominated by salinity gradients. However, in many situations, temperature gradients could be sufficiently large to influence the baroclinic motion. In this paper, we present an approach to simulate water temperature using outputs from advanced meteorological models. This modeling approach was applied to simulate annual variations of water temperatures of Puget Sound, a fjordal estuary in the Pacific Northwest of USA. Meteorological parameters from North American Region Re-analysis (NARR) model outputs were evaluated with comparisons to observed data at real-time meteorological stations. Model results demonstrated that NARR outputs can be used to drive coastal ocean models for realistic simulations of long-term water-temperature distributions in Puget Sound. Model results indicated that the net flux from NARR can be further improved with the additional information from real-time observations.
The CNO Isotopes: Deep Circulation in Red Giants and First and Second Dredge-up
Arnold I. Boothroyd; I. -Juliana Sackmann
1998-06-16
It is demonstrated that deep circulation mixing below the base of the standard convective envelope, and the consequent "cool bottom processing" (CBP) of the CNO isotopes, can reproduce the trend with stellar mass of the C-12/C-13 observations in low mass red giants. (This trend is opposite to what is expected from standard first dredge-up.) Our models assume that extra mixing always reaches to the same distance in temperature from the H-burning shell, and that CBP begins when the H-burning shell erases the molecular weight discontinuity ("mu-barrier") established by first dredge-up. For Pop I stars, none of the other CNO isotopes except N-15 are expected to be altered by CBP. (If O-18 depletion occurs on the AGB, as some observations suggest, it would require that extra mixing reach closer to the H-burning shell on the AGB than on the RGB --- and should also result in a much lower C-12/C-13 ratio than is observed.) CBP increases as one reduces the stellar mass or metallicity --- roughly as 1/M^2 on the RGB, due to the longer RGB of low mass stars, and as 1/Z, due to higher H-shell burning temperatures at low metallicity. In low mass Pop II stars, all the CNO isotopes are expected to be altered by CBP. Field Pop II stars exhibit RGB abundances consistent with the predictions of our CBP models that have been normalized to reproduce the Pop I RGB abundances, but globular cluster stars are observed to encounter much more extensive processing; also, CBP is observed to start near the base of the globular cluster RGB (overcoming any "mu-barrier"). Standard first and second dredge-up are also presented, and enrichment of the interstellar medium, relative to SN. For light elements, see astro-ph/9512122.
Daniels, Megan Hanako
2010-01-01
groundwater, land-surface, and mesoscale atmospheric model-and modification of mesoscale circulations. , Mon. Wea.J. Davis, The effects of mesoscale surface heterogeneity on
Generalized Jordan-Wigner Transformations
Batista, C. D.; Ortiz, G.
2001-02-05
We introduce a new spin-fermion mapping, for arbitrary spin S generating the SU(2) group algebra, that constitutes a natural generalization of the Jordan-Wigner transformation for S=1/2. The mapping, valid for regular lattices in any spatial dimension d , serves to unravel hidden symmetries. We illustrate the power of the transformation by finding exact solutions to lattice models previously unsolved by standard techniques. We also show the existence of the Haldane gap in S=1 bilinear nearest-neighbor Heisenberg spin chains and discuss the relevance of the mapping to models of strongly correlated electrons. Moreover, we present a general spin-anyon mapping for the case d{<=}2 .
Generalized Jordan-Wigner Transformations
C. D. Batista; G. Ortiz
2000-08-25
We introduce a new spin-fermion mapping, for arbitrary spin $S$ generating the SU(2) group algebra, that constitutes a natural generalization of the Jordan-Wigner transformation for $S=1/2$. The mapping, valid for regular lattices in any spatial dimension $d$, serves to unravel hidden symmetries in one representation that are manifest in the other. We illustrate the power of the transformation by finding exact solutions to lattice models previously unsolved by standard techniques. We also present a proof of the existence of the Haldane gap in $S=$1 bilinear nearest-neighbors Heisenberg spin chains and discuss the relevance of the mapping to models of strongly correlated electrons. Moreover, we present a general spin-anyon mapping for the case $d \\leq 2$.
Bhattacharya, R.; Sarkar, B.; Vaghela, H.; Shah, N.
2014-01-29
Operation and control of superconducting (SC) magnets in the fusion devices having tokamak configuration opens up the domain of varying peak thermal energy environment as a function of time, commensurate with the plasma pulses. The varied thermal energy environment, thus propagated to upstream of the cooling system, is responsible for the system level instability of the overall cryogenic system. The cryogenic distribution system, the regime of first impact point, therefore, has to be tuned so as to stay at the nearly stable zone of operation. The configuration of the cryogenic distribution system, considered in the present study, involves a liquid helium (LHe) bath as a thermal buffer, LHe submerged heat exchangers and cold circulator apart from the valves for implementations of the precise controls. The cold circulator supplies the forced flow supercritical helium, used for the cooling of SC magnets. The transients of the thermal energy pulses can be attenuated in the cryogenic distribution system by various methodologies. One of the adopted methodologies in the present study is with the precise speed control of the cold circulators. The adopted methodology is applied to various configurations of arrangements of internal components in the distribution system for obtaining system responses with superior attenuation of energy pulses. The process simulation approach, assumptions, considered inputs and constraints, process modeling with different configuration as well as results to accomplish the control scheme for the attenuation of the thermal energy pulses are described.
Black holes in general relativity
Visser, Matt
2009-01-01
What is going on (as of August 2008) at the interface between theoretical general relativity, string-inspired models, and observational astrophysics? Quite a lot. In this mini-survey I will make a personal choice and focus on four specific questions: Do black holes "exist"? (For selected values of the word "exist".) Is black hole formation and evaporation unitary? Can one mimic a black hole to arbitrary accuracy? Can one detect the presence of a horizon using local physics?
Agent Model Development for Assessing Climate-Induced Geopolitical Instability.
Boslough, Mark B.; Backus, George A.
2005-12-01
We present the initial stages of development of new agent-based computational methods to generate and test hypotheses about linkages between environmental change and international instability. This report summarizes the first year's effort of an originally proposed three-year Laboratory Directed Research and Development (LDRD) project. The preliminary work focused on a set of simple agent-based models and benefited from lessons learned in previous related projects and case studies of human response to climate change and environmental scarcity. Our approach was to define a qualitative model using extremely simple cellular agent models akin to Lovelock's Daisyworld and Schelling's segregation model. Such models do not require significant computing resources, and users can modify behavior rules to gain insights. One of the difficulties in agent-based modeling is finding the right balance between model simplicity and real-world representation. Our approach was to keep agent behaviors as simple as possible during the development stage (described herein) and to ground them with a realistic geospatial Earth system model in subsequent years. This work is directed toward incorporating projected climate data--including various C02 scenarios from the Intergovernmental Panel on Climate Change (IPCC) Third Assessment Report--and ultimately toward coupling a useful agent-based model to a general circulation model.3
California Wintertime Precipitation in Regional and Global Climate Models
Caldwell, P M
2009-04-27
In this paper, wintertime precipitation from a variety of observational datasets, regional climate models (RCMs), and general circulation models (GCMs) is averaged over the state of California (CA) and compared. Several averaging methodologies are considered and all are found to give similar values when model grid spacing is less than 3{sup o}. This suggests that CA is a reasonable size for regional intercomparisons using modern GCMs. Results show that reanalysis-forced RCMs tend to significantly overpredict CA precipitation. This appears to be due mainly to overprediction of extreme events; RCM precipitation frequency is generally underpredicted. Overprediction is also reflected in wintertime precipitation variability, which tends to be too high for RCMs on both daily and interannual scales. Wintertime precipitation in most (but not all) GCMs is underestimated. This is in contrast to previous studies based on global blended gauge/satellite observations which are shown here to underestimate precipitation relative to higher-resolution gauge-only datasets. Several GCMs provide reasonable daily precipitation distributions, a trait which doesn't seem tied to model resolution. GCM daily and interannual variability is generally underpredicted.
Not Available
1995-01-01
The test plan is designed to demonstrate that oil shale co-combusted with municipal solid waste (MSW) can reduce gaseous pollutants (SO{sub 2}, CO) to acceptable levels (90%+ reduction) and produce a cementitious ash which will, at a minimum, be acceptable in normal land fills. The small-scale combustion testing will be accomplished in a 6-in. circulating fluid bed combustor (CFBC) at Hazen Research Laboratories. This work will be patterned after the study the authors conducted in 1988 when coal and oil shale were co-combusted in a program sponsored by the Electric Power Research Institute. The specific purpose of the test program will be to: determine the required ratio of oil shale to MSW by determining the ratio of absorbent to pollutant (A/P); determine the effect of temperature and resident time in the reactor; and determine if kinetic model developed for coal/oil shale mixture is applicable.
Generalized Elitzur's Theorem and Dimensional Reduction
Cristian D. Batista; Zohar Nussinov
2005-03-10
We extend Elitzur's theorem to systems with symmetries intermediate between global and local. In general, our theorem formalizes the idea of {\\it dimensional reduction}. We apply the results of this generalization to many systems that are of current interest. These include liquid crystalline phases of Quantum Hall systems, orbital systems, geometrically frustrated spin lattices, Bose metals, and models of superconducting arrays.
Wind-driven circulation on a shallow, stratified shelf
Austin, Jay Alan
1999-01-01
A detailed examination of the development of a deep convection event observed in the Greenland Sea in 1988-89 is carried out through a combination of modeling, scale estimates, and data analysis. We develop a prognostic ...
Residual Circulation in the Ocean R. Ferrari and A. Plumb
Ferrari, Raffaele
requires some eddy parameterization. Most climate models have adopted the Gent and McWilliams (hereafter GM suggest that mesoscale eddies tend to homogenize potential vorticity (hereafter PV) along isopycnals
Jin He
2010-01-29
Mach Principle presents the absolute universe. For example, when Einstein stood on the ground and relaxed, his arms fell down naturally. However, if he rotated his body then his arms were lifted up as the rotation was faster and faster. Mach principle is that the matter of the whole universe can affect local dynamic systems. That is, the matter of the whole universe sets up the local absolute reference frames. However, Einstein's general theory of relativity is against the absolute reference frames of Mach Principle.