Global analysis of intraplate basins
NASA Astrophysics Data System (ADS)
Heine, C.; Mueller, D. R.; Dyksterhuis, S.
2005-12-01
Broad intraplate sedimentary basins often show a mismatch of lithospheric extension factors compared to those inferred from sediment thickness and subsidence modelling, not conforming to the current understanding of rift basin evolution. Mostly, these basins are underlain by a very heterogeneous and structurally complex basement which has been formed as a product of Phanerozoic continent-continent or terrane/arc-continent collision and is usually referred to as being accretionary. Most likely, the basin-underlying substrate is one of the key factors controlling the style of extension. In order to investigate and model the geodynamic framework and mechanics controlling formation and evolution of these long-term depositional regions, we have been analysing a global set of more than 200 basins using various remotely sensed geophysical data sets and relational geospatial databases. We have compared elevation, crustal and sediment thickness, heatflow, crustal structure, basin ages and -geometries with computed differential beta, anomalous tectonic subsidence, and differential extension factor grids for these basins. The crust/mantle interactions in the basin regions are investigated using plate tectonic reconstructions in a mantle convection framework for the last 160 Ma. Characteristic parameters and patterns derived from this global analysis are then used to generate a classification scheme, to estimate the misfit between models derived from either crustal thinning or sediment thickness, and as input for extension models using particle-in-cell finite element codes. Basins with high differential extension values include the ``classical'' intraplate-basins, like the Michigan Basin in North America, the Zaire Basin in Africa, basins of the Arabian Penisula, and the West Siberian Basin. According to our global analysis so far, these basins show, that with increasing basin age, the amount of crustal extension vs. the extension values estimated from sediment thickness
PECH, S.H.
2000-08-23
This report describes the methodology used in conducting the K Basins Hazard Analysis, which provides the foundation for the K Basins Final Safety Analysis Report. This hazard analysis was performed in accordance with guidance provided by DOE-STD-3009-94, Preparation Guide for U. S. Department of Energy Nonreactor Nuclear Facility Safety Analysis Reports and implements the requirements of DOE Order 5480.23, Nuclear Safety Analysis Report.
WEBB, R.H.
1999-12-29
This report describes the methodology used in conducting the K Basins Hazard Analysis, which provides the foundation for the K Basins Safety Analysis Report (HNF-SD-WM-SAR-062, Rev.4). This hazard analysis was performed in accordance with guidance provided by DOE-STD-3009-94, Preparation Guide for U. S. Department of Energy Nonreactor Nuclear Facility Safety Analysis Reports and implements the requirements of DOE Order 5480.23, Nuclear Safety Analysis Report.
Porten, D.R.; Crowe, R.D.
1994-12-16
The purpose of this accident safety analysis is to document in detail, analyses whose results were reported in summary form in the K Basins Safety Analysis Report WHC-SD-SNF-SAR-001. The safety analysis addressed the potential for release of radioactive and non-radioactive hazardous material located in the K Basins and their supporting facilities. The safety analysis covers the hazards associated with normal K Basin fuel storage and handling operations, fuel encapsulation, sludge encapsulation, and canister clean-up and disposal. After a review of the Criticality Safety Evaluation of the K Basin activities, the following postulated events were evaluated: Crane failure and casks dropped into loadout pit; Design basis earthquake; Hypothetical loss of basin water accident analysis; Combustion of uranium fuel following dryout; Crane failure and cask dropped onto floor of transfer area; Spent ion exchange shipment for burial; Hydrogen deflagration in ion exchange modules and filters; Release of Chlorine; Power availability and reliability; and Ashfall.
Morgan, David S.; Jones, Joseph L.
1999-01-01
A numerical ground-water flow model of a hypothetical basin typical of those in the Puget Sound Lowland of western Washington simulated effects of ground-water withdrawals on rates of natural discharge to streams and springs. The model was calibrated to natural conditions and simulated effects by varying distance from well to stream, presence of confining layers, pumping rate, depth of pumped aquifer, distance from well to a bluff, well density, and recharge rate.
Numerical analysis of bifurcations
Guckenheimer, J.
1996-06-01
This paper is a brief survey of numerical methods for computing bifurcations of generic families of dynamical systems. Emphasis is placed upon algorithms that reflect the structure of the underlying mathematical theory while retaining numerical efficiency. Significant improvements in the computational analysis of dynamical systems are to be expected from more reliance of geometric insight coming from dynamical systems theory. {copyright} {ital 1996 American Institute of Physics.}
Ketkar, S.P.
1999-07-01
This new volume is written for both practicing engineers who want to refresh their knowledge in the fundamentals of numerical thermal analysis as well as for students of numerical heat transfer. it is a handy desktop reference that covers all the basics of finite difference, finite element, and control volume methods. In this volume, the author presents a unique hybrid method that combines the best features of finite element modeling and the computational efficiency of finite difference network solution techniques. It is a robust technique that is used in commercially available software. The contents include: heat conduction: fundamentals and governing equations; finite difference method; control volume method; finite element method; the hybrid method; and software selection.
NASA Astrophysics Data System (ADS)
Galushkin, Yu. I.; El Maghbi, Ali; El Gtlawi, M.
2014-01-01
The GALO basin modeling system has been applied for the numerical reconstruction of the subsidence history, variations in temperature, and maturity of the organic matter of sedimentary rocks composing the main tectonic structures of Sirte Basin. The reconstruction was carried out for eight sedimentary cross sections along the profile stretching from the Cyrenaica Platform on the eastern coast of the basin to the Hun Graben on its western wall. The interval of depths for temperature calculations included the sedimentary layer, consolidated crust, and the mantle to below 100 km. This extensive depth coverage made it possible to use the analysis of the variations in the tectonic subsidence of the basin for estimating the amplitudes and duration of the events of thermal activation and extension of the lithosphere of the basin in the history of its evolution. The modeling suggests that thermal activations of the lithosphere in the Albian-Cenomanian and Oligocene-Pleistocene are common for all tectonic structures of the Sirte Basin and the Cyrenaica Platform and that a relatively high temperature regime is also characteristic of the present-day conditions in the Sirte Basin and Cyrenaica Platform. To a considerable extent, such a regime is caused by the thermal activation of the lithosphere of the basin during the last 10 Ma. The intensity of this activation is highest in the western part of the basin, where it is accompanied by the highest erosion amplitudes. The analysis of the variations in tectonic subsidence of the basement also suggests a series of intervals of lithospheric extension, which accounts for the stages of relatively rapid subsidence of the basin. Two intervals of significant extension of the lithosphere in the Upper Cretaceous and Paleocene are common for all areas within the basin. Here, the total amplitudes of the crustal extension attained 1.5 in the central part of the Sirte Basin (the Ajdabiya and Maradah troughs and Zelten and Dahra platforms
NASA Astrophysics Data System (ADS)
Li, Lu; Qiu, Nansheng; Xu, Wei
2016-04-01
Jiyang sub-basin is an oil-rich depression located in the southeast of Bohai Bay Basin, which is one of the most important hydrocarbon area in east of China. The thermal-rheological structure of the lithosphere can explain the dynamics evolution processes of basins, continental margins and orogenic belts, which directly reflects the characteristics of the lithosphere geodynamics. Nevertheless it is poorly to understand the evolution of lithospheric thermal-rheological structure in Jiyang sub-basin and its implication for basin extension. In this study, two dimensional numerical modelling is applied to calculate the paleo-temperature field and the thermo-lithospheric structure, which are used to estimate the evolution of lithospheric thermal-rheological structure. The results of study show that in Mesozoic the lithosphere was of relative rigidity and stable, as featured by large thickness and strength whereas after late Cretaceous the lithospheric strength decreased rapidly. The analysis of thermal-rheological properties shows that the lithospheric thermo-lithospheric structure is sandwiched-like with two ductile layers and two brittle layers. The upper crust is usually brittle. The brittle layers appear at outer 20km of the crust, below 20km ductile deformation predominates. There is also a 10km brittle layer on the top of the upper mantle. The integrated lithospheric yield strength is about 1.3-4.5×1012N/m, showing a weak lithosphere which may support the idea that the extension achieved by the ductile flow below the brittle layers. Keywords: lithospheric thermal-rheological structure; Jiyang sub-basin; Numerical modeling
Numerical models of carbonate hosted gold mineralization, Great Basin Nevada
NASA Astrophysics Data System (ADS)
Person, M.; Hofstra, A.; Gao, Y.; Sweetkind, D.; Banerjee, A.
2006-12-01
The Great Basin, Nevada contains many modern hydrothermal system and world class gold deposits hosted within Paleozoic carbonate rocks. Temperature profiles, fluid inclusion studies, and isotopic evidence suggest that modern geothermal and fossil hydrothermal systems associated with gold mineralization share many common features including the absence of a clear magmatic source, flow restricted to fault zones, and remarkably high temperatures at shallow depth. While the plumbing of these systems is not well understood, geochemical and isotopic data suggest that fluid circulation along fault zones is relatively deep (greater than 5 km) and comprised of relatively unexchanged Pleistocene meteoric water with small (less than 2.5 per mill) shifts from the MWL. Many fossil ore-forming systems were also dominated by meteoric water, but are usually exhibit shifts of 5 to 15 per mill from the MWL. Here we present two-dimensional numerical models to reconstruct the plumbing of modern geothermal and Tertiary hydrothermal systems in the Great Basin. Multiple tracers are used in our models, including O- and C-isotopic compositions of fluids/rocks, silica transport/ precipitation, and temperature anomalies, to constrain the plumbing of these systems. Our results suggest that both fossil hydrothermal and modern geothermal systems were probably driven by natural convection cells associated with localized high basal heating. We conclude that the fault controlled flow systems responsible for the genesis of Carlin gold mineralization and modern geothermal systems had to be transient in nature. Permeability changes within the carbonate reservoir was probably associated with extensional tectonic events.
Chronologic Analysis of Terrestrial Sediments and Basin Evolution
NASA Technical Reports Server (NTRS)
Burbank, D.
1985-01-01
The use of magnetic-polarity stratigraphy to provide detailed chronologies of numerous areas within a sedimentary basin is discussed. Sediments suitable for magnetostratigraphic studies are identified. Sets of figures intended to illustrate some of the applications of magnetic-polarity stratigraphy to various aspects of basin analysis are given. Most of the examples are drawn from the Himalayan molasse (Indo-Gangetic foredeep) in northern Pakistan and northwestern India. Each of the figures illustrates an example of how detailed chronologies can be utilized in enhancing and refining models of basin analysis and tectonic deformation.
Numerical analysis of engine instability
NASA Astrophysics Data System (ADS)
Habiballah, M.; Dubois, I.
Following a literature review on numerical analyses of combustion instability, to give the state of the art in the area, the paper describes the ONERA methodology used to analyze the combustion instability in liquid propellant engines. Attention is also given to a model (named Phedre) which describes the unsteady turbulent two-phase reacting flow in a liquid rocket engine combustion chamber. The model formulation includes axial or radial propellant injection, baffles, and acoustic resonators modeling, and makes it possible to treat different engine types. A numerical analysis of a cryogenic engine stability is presented, and the results of the analysis are compared with results of tests of the Viking engine and the gas generator of the Vulcain engine, showing good qualitative agreement and some general trends between experiments and numerical analysis.
NASA Astrophysics Data System (ADS)
Potter, R. W. K.; Head, J. W., III
2014-12-01
Impact cratering is a fundamental geological process throughout the Solar System. The Moon is an ideal location to document the impact cratering process due to the number and excellent state of preservation of large craters and basins, and the wide range of geological, geophysical, topographic, mineralogic, remote sensing and returned sample data. Despite the number and excellent preservation state of many large complex craters and basins, their formation and the origin of their structural features and the stages in their evolution remain contentious. To more comprehensively document the final stage of lunar impact basin formation, we have compiled detailed topographic, geological and mineralogic maps of several type examples of peak-ring and multi-ring basins, including the Orientale basin. These data include the mineralogic characteristics of basin ring structures and assist in the interpretation of the target stratigraphy, and the depth of origin of basin rings. Data for the current structure of basins is compared to numerical model outputs of basin-forming impacts, which track formation to the conclusion of dynamic processes (2 to 3 hours after impact). We use the Orientale basin as an example and provide combined correlations and interpretations that assign rings to various stages in the numerical models, and compare these candidates to crustal stratigraphy, with the ultimate aim of producing a consistent model for large crater/basin formation. The shock physics code iSALE is used to numerically model the basin-scale impacts. Constitutive equations and equations of state for materials analogous to the lunar crust (gabbroic anorthosite) and mantle (dunite) are used. Aspects of the numerically-produced lunar basins (e.g., material distribution and accumulated stress) are compared and contrasted to remote observations and geological maps of the Orientale rings and geological units, including ejecta and impact melt deposits.
Numerical analysis of Stirling engine
NASA Astrophysics Data System (ADS)
Sekiya, Hiroshi
1992-11-01
A simulation model of the Stirling engine based on the third order method of analysis is presented. The fundamental equations are derived by applying conservation laws of physics to the machine model, the characteristic equations for heat transfer and gas flow are represented, and a numerical calculation technique using these equations is discussed. A numerical model of the system for balancing pressure in four cylinders is included in the simulation model. Calculations results from the model are compared with experimental results. A comparable study of engine performance using helium and hydrogen as working gas is conducted, clarifying the heat transfer and gas flow characteristics, and the effects of temperature conditions in the hot and cold engine sections on driving conditions. The design optimization of the heat exchanger is addressed.
Using PASCAL for numerical analysis
NASA Technical Reports Server (NTRS)
Volper, D.; Miller, T. C.
1978-01-01
The data structures and control structures of PASCAL enhance the coding ability of the programmer. Proposed extensions to the language further increase its usefulness in writing numeric programs and support packages for numeric programs.
An Ensemble Numerical Modeling Study of Atlantic Basin Hurricane Intensification
NASA Astrophysics Data System (ADS)
Brown, Bonnie R.
Rapid intensification of tropical cyclones is an active area of research in the atmospheric sciences due to the difficulty of forecasting cyclone intensity and the unclear mechanism by which a hurricane my undergo explosive deepening. Ensemble numerical modeling studies of six tropical cyclones from 2009, 2010 and 2011 which underwent periods of strong intensification are conducted here. The goal is to identify common storm structures in intensifying hurricanes while filling a gap in the current research between case studies of rapid intensification and climatological/statistical type studies of hurricane intensification rates by using a compositing method. A 96-member ensemble is run for a 24 hour forecast using the Weather Research and Forecasting (WRF) model for hurricanes Bill (2009), Earl (2010), Igor (2010), Julia (2010), Katia (2011), and Ophelia (2011). Ensemble sensitivity analysis is used to investigate which patterns in the analysis have a strong influence on the forecast intensity and then a novel sensitivity compositing is used to identify common patterns which affect the forecast intensity. It is found that these hurricanes are all predicted to respond to an increased primary and secondary circulation, an increased warm core, a raised tropopause and moistening of rain bands with an increased forecast intensity. Perturbed initial conditions show a linear model response for small perturbations but also signs of non-linearity at large perturbations, indicating that these sensitivity patterns are robust for limited additional strengthening of the hurricane. When perturbations are partitioned into dry and moist variables, it is seen that most of the model response is achieved by the dry dynamics. Further investigation is conducted into the rapid intensification of Earl (2010) and Igor (2010) but creating ensemble forecasts with additional, high-resolution nested domains which allow explicit convection. When the ensemble sensitivity analysis is repeated
Numerical Relativity meets Data Analysis
NASA Astrophysics Data System (ADS)
Schmidt, Patricia
2016-03-01
Gravitational waveforms (GW) from coalescing black hole binaries obtained by Numerical Relativity (NR) play a crucial role in the construction and validation of waveform models used as templates in GW matched filter searches and parameter estimation. In previous efforts, notably the NINJA and NINJA-2 collaborations, NR groups and data analysts worked closely together to use NR waveforms as mock GW signals to test the search and parameter estimation pipelines employed by LIGO. Recently, however, NR groups have been able to simulate hundreds of different binary black holes systems. It is desirable to directly use these waveforms in GW data analysis, for example to assess systematic errors in waveform models, to test general relativity or to appraise the limitations of aligned-spin searches among many other applications. In this talk, I will introduce recent developments that aim to fully integrate NR waveforms into the data analysis pipelines through a standardized interface. I will highlight a number of select applications for this new infrastructure.
BasinVis 1.0: A MATLAB®-based program for sedimentary basin subsidence analysis and visualization
NASA Astrophysics Data System (ADS)
Lee, Eun Young; Novotny, Johannes; Wagreich, Michael
2016-06-01
Stratigraphic and structural mapping is important to understand the internal structure of sedimentary basins. Subsidence analysis provides significant insights for basin evolution. We designed a new software package to process and visualize stratigraphic setting and subsidence evolution of sedimentary basins from well data. BasinVis 1.0 is implemented in MATLAB®, a multi-paradigm numerical computing environment, and employs two numerical methods: interpolation and subsidence analysis. Five different interpolation methods (linear, natural, cubic spline, Kriging, and thin-plate spline) are provided in this program for surface modeling. The subsidence analysis consists of decompaction and backstripping techniques. BasinVis 1.0 incorporates five main processing steps; (1) setup (study area and stratigraphic units), (2) loading well data, (3) stratigraphic setting visualization, (4) subsidence parameter input, and (5) subsidence analysis and visualization. For in-depth analysis, our software provides cross-section and dip-slip fault backstripping tools. The graphical user interface guides users through the workflow and provides tools to analyze and export the results. Interpolation and subsidence results are cached to minimize redundant computations and improve the interactivity of the program. All 2D and 3D visualizations are created by using MATLAB plotting functions, which enables users to fine-tune the results using the full range of available plot options in MATLAB. We demonstrate all functions in a case study of Miocene sediment in the central Vienna Basin.
NASA Astrophysics Data System (ADS)
Dai, Liming; Li, Sanzhong; Lou, Da; Liu, Xin; Suo, Yanhui; Yu, Shan
2014-06-01
The East China Sea Shelf Basin is an important oil- and gas-bearing basin in the West Pacific continental margin. This region was affected by subduction of the Pacific Plate and the Philippine Plate in Cenozoic and experienced multi-stage tectonic inversions. This paper presents results from a numerical simulation by finite element method to the Xihu Sag in the East China Sea Shelf Basin and neighboring areas in an attempt to evaluate the WNW-directed compression on the sag during Late Miocene. Based on comprehensive structural analysis of a large number of seismic profiles, we determine the structural geometry of the sag, including the basement of the basin, the sedimentary cover, and 29 major faults in the Xihu Sag. Simulation results show that under continuous WNW-directed compression, tectonic inversion occurred firstly in the Longjing and Yuquan tectonic zones in the sag. Based on quantitative analysis of vertical displacement field of the Xihu Sag and peripheral areas and its stress intensity evolution, we identify a compressional regime in the Longjing Anticline Zone with a gradually propagated uplifting from south to north; whereas the propagation of uplifting in the Yuquan Anticline Zone is from north to south. The inversion intensity decreases from north to south. The formation of the tectonic inversion zone in the Xihu Sag is not only correlated to the direction of compression and fault patterns in the basin, but also closely related to the spatial configuration of fault surfaces of the Xihu-Jilong Fault in the Xihu Sag.
Numerical Modeling of Water Circulation and Pollutant Transport in a Shallow Basin
NASA Astrophysics Data System (ADS)
Charafi, My. M.; Sadok, A.; Kamal, A.; Menai, A.
A two-dimensional numerical model was developed1-3 to simulate the sediment and pollutant transport in a shallow basin. The developed model consist of two modules: Hydrodynamic module and sediment/pollutant transport module. A numerical hydrodynamic module based on the Saint-Venant equations, is resolved by a MacCormack numerical scheme and is used to simulate the circulation pattern in the basin. The obtained flow circulation is used as an input to the sediment/pollutant transport module to simulate the transport and dispersion of a pollutant emitted into the basin. To calibrate the numerical model, the distorted scale model of the Windermere Basin4 was used. In this physical model, the flow visualization and pollutant transport experiments provide a good calibration. The simulated results were found to be in good agreement with the experimental measurements and the results in Ref. 4. With the aid of the validated model, the influence of the construction of dikes on the residence time distributions in the basin was examined.
Numerical Package in Computer Supported Numeric Analysis Teaching
ERIC Educational Resources Information Center
Tezer, Murat
2007-01-01
At universities in the faculties of Engineering, Sciences, Business and Economics together with higher education in Computing, it is stated that because of the difficulty, calculators and computers can be used in Numerical Analysis (NA). In this study, the learning computer supported NA will be discussed together with important usage of the…
Flemings, P.B.; Jordan, T.E.; Reynolds, S.
1986-05-01
Lithospheric flexure that generates basin in a broke foreland setting (e.g., the Laramide foreland of Wyoming) is a three-dimensional system related to shortening along basin-bounding faults. The authors modeled the elastic flexure in three dimensions for two broken foreland basins: the early Cenozoic Green River basin and the analogous late Cenozoic Bermejo basin of Argentina. Each basin is located between a thrust belt and a reverse-fault-bounded basement uplift. Both basins are asymmetric toward the basement uplifts and have a central basement high: the Rock Springs uplift and the Pie de Palo uplift, respectively. The model applies loads generated by crustal thickening to an elastic lithosphere overlying a fluid mantle. Using the loading conditions of the Bermejo basin based on topography, limited drilling, and reflection and earthquake seismology, the model predicts the current Bermejo basin geometry. Similarly, flexure under the loading conditions in the Green River basin, which are constrained by stratigraphy, well logs, and seismic profiling and summed for Late Cretaceous (Lance Formation) through Eocene (Wasatch Formation), successfully models the observed geometry of the pre-Lance surface. Basin depocenters (> 4 km for the Green River basin; > 7 km for the Bermejo basin) and central uplifts are predicted to result from constructive interference of the nonparallel applied loads. Their Bermejo model implies that instantaneous basin geometry is successfully modeled by crustal loading, whereas the Green River basin analysis suggests that basin evolution can be modeled over large time steps (e.g., 20 Ma). This result links instantaneous basin geometry to overall basin evolution and is a first step in predicting stratigraphic development.
SE Great Basin Play Fairway Analysis
Adam Brandt
2015-11-15
Within this submission are multiple .tif images with accompanying metadata of magnetotelluric conductor occurrence, fault critical stress composite risk segment (CRS), permeability CRS, Quaternary mafic extrusions, Quaternary fault density, and Quaternary rhyolite maps. Each of these contributed to a final play fairway analysis (PFA) for the SE Great Basin study area.
NASA Astrophysics Data System (ADS)
Rybarski, S.; Pohll, G.; Pohlmann, K.; Plume, R.
2014-12-01
In recent years, hydraulic fracturing (fracking) has become an increasingly popular method for extraction of oil and natural gas from tight formations. Concerns have been raised over a number of environmental risks associated with fracking, including contamination of groundwater by fracking fluids, upwelling of deep subsurface brines, and methane migration. Given the potentially long time scale for contaminant transport associated with hydraulic fracturing, numerical modeling remains the best practice for risk assessment. Oil shale in the Humboldt basin of northeastern Nevada has now become a target for hydraulic fracturing operations. Analysis of regional and shallow groundwater flow is used to assess several potential migration pathways specific to the geology and hydrogeology of this basin. The model domain in all simulations is defined by the geologic structure of the basin as determined by deep oil and gas well bores and formation outcrops. Vertical transport of gaseous methane along a density gradient is simulated in TOUGH2, while fluid transport along faults and/or hydraulic fractures and lateral flow through more permeable units adjacent to the targeted shale are modeled in FEFLOW. Sensitivity analysis considers basin, fault, and hydraulic fracturing parameters, and results highlight key processes that control fracking fluid and methane migration and time scales under which it might occur.
Tularosa Basin Play Fairway Analysis: Strain Analysis
Adam Brandt
2015-11-15
A DEM of the Tularosa Basin was divided into twelve zones, each of which a ZR ratio was calculated for. This submission has a TIFF image of the zoning designations, along with a table with respective ZR ratio calculations in the metadata.
Khangaonkar, Tarang; Yang, Zhaoqing; Kim, Tae Yun; Roberts, Mindy
2011-07-20
Through extensive field data collection and analysis efforts conducted since the 1950s, researchers have established an understanding of the characteristic features of circulation in Puget Sound. The pattern ranges from the classic fjordal behavior in some basins, with shallow brackish outflow and compensating inflow immediately below, to the typical two-layer flow observed in many partially mixed estuaries with saline inflow at depth. An attempt at reproducing this behavior by fitting an analytical formulation to past data is presented, followed by the application of a three-dimensional circulation and transport numerical model. The analytical treatment helped identify key physical processes and parameters, but quickly reconfirmed that response is complex and would require site-specific parameterization to include effects of sills and interconnected basins. The numerical model of Puget Sound, developed using unstructured-grid finite volume method, allowed resolution of the sub-basin geometric features, including presence of major islands, and site-specific strong advective vertical mixing created by bathymetry and multiple sills. The model was calibrated using available recent short-term oceanographic time series data sets from different parts of the Puget Sound basin. The results are compared against (1) recent velocity and salinity data collected in Puget Sound from 2006 and (2) a composite data set from previously analyzed historical records, mostly from the 1970s. The results highlight the ability of the model to reproduce velocity and salinity profile characteristics, their variations among Puget Sound subbasins, and tidally averaged circulation. Sensitivity of residual circulation to variations in freshwater inflow and resulting salinity gradient in fjordal sub-basins of Puget Sound is examined.
NASA Astrophysics Data System (ADS)
Chaljub, Emmanuel; Maufroy, Emeline; deMartin, Florent; Hollender, Fabrice; Guyonnet-Benaize, Cédric; Manakou, Maria; Savvaidis, Alexandros; Kiratzi, Anastasia; Roumelioti, Zaferia; Theodoulidis, Nikos
2014-05-01
Understanding the origin of the variability of earthquake ground motion is critical for seismic hazard assessment. Here we present the results of a numerical analysis of the sensitivity of earthquake ground motion to seismic source parameters, focusing on the Mygdonian basin near Thessaloniki (Greece). We use an extended model of the basin (65 km [EW] x 50 km [NS]) which has been elaborated during the Euroseistest Verification and Validation Project. The numerical simulations are performed with two independent codes, both implementing the Spectral Element Method. They rely on a robust, semi-automated, mesh design strategy together with a simple homogenization procedure to define a smooth velocity model of the basin. Our simulations are accurate up to 4 Hz, and include the effects of surface topography and of intrinsic attenuation. Two kinds of simulations are performed: (1) direct simulations of the surface ground motion for real regional events having various back azimuth with respect to the center of the basin; (2) reciprocity-based calculations where the ground motion due to 980 different seismic sources is computed at a few stations in the basin. In the reciprocity-based calculations, we consider epicentral distances varying from 2.5 km to 40 km, source depths from 1 km to 15 km and we span the range of possible back-azimuths with a 10 degree bin. We will present some results showing (1) the sensitivity of ground motion parameters to the location and focal mechanism of the seismic sources; and (2) the variability of the amplification caused by site effects, as measured by standard spectral ratios, to the source characteristics
Precambrian shield and basement tectonics in sedimentary basin analysis
Touborg, J.F.
1984-04-01
This study focused on the use of (1) regional structural analysis of basement and Precambrian rocks surrounding a sedimentary basin, and (2) tracing basement structures into the sedimentary basin. The structural analysis of the Precambrian shield has a fundamental bearing on interpretation of overlying sedimentary cover rocks. This is expressed in the southern part of the Hudson's Bay basin and its southeastern arm, the Moose River basin. For instance, the rims of both basins are controlled by faults or graben structures. Approximately 13 major fault systems with strike lengths of 200-300 km (125-186 mi) or more can be traced from the exposed Precambrian shield into the basin in terms of lineament arrays and/or aeromagnetic and/or gravity signature. The data suggest reactivation of faults during basin sedimentation. This type of basement structural analysis in areas adjacent to sedimentary basins can provide a valuable interpretation base for subsequent seismic surveys and basin evaluation.
NASA Astrophysics Data System (ADS)
Istanbulluoglu, E.; Vivoni, E. R.; Ivanov, V. Y.; Bras, R. L.
2005-12-01
Landscape morphology has an important control on the spatial and temporal organization of basin hydrologic response to climate forcing, affecting soil moisture redistribution as well as vegetation function. On the other hand, erosion, driven by hydrology and modulated by vegetation, produces landforms over geologic time scales that reflect characteristic signatures of the dominant land forming process. Responding to extreme climate events or anthropogenic disturbances of the land surface, infrequent but rapid forms of erosion (e.g., arroyo development, landsliding) can modify topography such that basin hydrology is significantly influenced. Despite significant advances in both hydrologic and geomorphic modeling over the past two decades, the dynamic interactions between basin hydrology, geomorphology and terrestrial ecology are not adequately captured in current model frameworks. In order to investigate hydrologic-geomorphic-ecologic interactions at the basin scale we present initial efforts in integrating the CHILD landscape evolution model (Tucker et al. 2001) with the tRIBS hydrology model (Ivanov et al. 2004), both developed in a common software environment. In this talk, we present preliminary results of the numerical modeling of the coupled evolution of basin hydro-geomorphic response and resulting landscape morphology in two sets of examples. First, we discuss the long-term evolution of both the hydrologic response and the resulting basin morphology from an initially uplifted plateau. In the second set of modeling experiments, we implement changes in climate and land-use to an existing topography and compare basin hydrologic response to the model results when landscape form is fixed (e.g. no coupling between hydrology and geomorphology). Model results stress the importance of internal basin dynamics, including runoff generation mechanisms and hydrologic states, in shaping hydrologic response as well as the importance of employing comprehensive
NASA Astrophysics Data System (ADS)
Gems, B.; Wörndl, M.; Gabl, R.; Weber, C.; Aufleger, M.
2014-02-01
Mountain debris cones in the Alpine region often provide space for dense population and cultivation. Hence, a great number of buildings are exposed to torrential hazards. In order to protect the settlement areas against flooding and overbank sedimentation, torrent defence structures are implemented at various locations within catchments. Directly at the debris cones, these protection measures often include a deposition basin at the fan apex and/or a confined channel that passes through the settlement. The work presented within this paper deals with the effect of specific outlet structure layouts, situated at the lower end of a selected deposition basin, on bed-load transport processes and flood protection. A case study analysis was accomplished comprising a 3-D numerical model (FLOW-3D) and a physical scale model test (1 : 30). The subject of investigation was the deposition basin of the Larsennbach torrent in the Austrian Northern Limestone Alps. The basin is situated on a large debris cone and opens out into a paved channel. Since the basin is undersized and the accumulation of sediment in the outlet section reduces the available cross section during floods, adjoining settlements are considerably endangered of lateral overtopping of both clear water and sediment. Aiming for an upgrade in flood protection, certain layouts for a "closing-off structure" at the outlet were tested within this project. For the most efficient design layout, its effect on flood protection, a continuous bed-load output from the basin and the best possible use of the retention volume are pointed out. The simple design of the structure and the key aspects that have to be taken into consideration for implementation are highlighted.
NASA Astrophysics Data System (ADS)
Gems, B.; Wörndl, M.; Gabl, R.; Weber, C.; Aufleger, M.
2013-07-01
Mountain debris cones in the Alpine region often provide space for dense population and cultivation. Hence, a great number of buildings are exposed to torrential hazards. In order to protect the settlement areas against flooding and overbank sedimentation, torrent defence structures are implemented directly at the debris cones. In many cases, these protection measures include a deposition basin at the head of the debris cone and/or a confined channel that passes or tracks through the settlement. The work presented within this paper deals with the effect of specific outlet structure layouts, situated at the lower end of a selected deposition basin, on bed-load transport processes and flood protection. A case study analysis was accomplished comprising of a 3-D-numerical model (FLOW-3D) and a physical scale model test (1:30). The subject of investigation was the deposition basin of the Larsennbach torrent in the Austrian Northern Limestone Alps. The basin is situated on a large debris cone and opens out into a paved channel. Since the basin is undersized and the accumulation of sediment in the outlet section reduces the available cross section during floods, adjoining settlements are considerably endangered of lateral overtopping of both clear water and sediment. Aiming for an upgrade in flood protection, certain layouts for a "closing-off structure" at the outlet were tested within this project. For the most efficient design layout, its effect on flood protection, a continuous bed-load output from the basin and the best possible use of the retention volume are pointed out. The simple design of the structure and the key aspects, that have to be taken into consideration for implementation, are highlighted.
Analysis of K west basin canister gas
Trimble, D.J., Fluor Daniel Hanford
1997-03-06
Gas and Liquid samples have been collected from a selection of the approximately 3,820 spent fuel storage canisters in the K West Basin. The samples were taken to characterize the contents of the gas and water in the canisters providing source term information for two subprojects of the Spent Nuclear Fuel Project (SNFP) (Fulton 1994): the K Basins Integrated Water Treatment System Subproject (Ball 1996) and the K Basins Fuel Retrieval System Subproject (Waymire 1996). The barrels of ten canisters were sampled for gas and liquid in 1995, and 50 canisters were sampled in a second campaign in 1996. The analysis results from the first campaign have been reported (Trimble 1995a, 1995b, 1996a, 1996b). The analysis results from the second campaign liquid samples have been documented (Trimble and Welsh 1997; Trimble 1997). This report documents the results for the gas samples from the second campaign and evaluates all gas data in terms of expected releases when opening the canisters for SNFP activities. The fuel storage canisters consist of two closed and sealed barrels, each with a gas trap. The barrels are attached at a trunion to make a canister, but are otherwise independent (Figure 1). Each barrel contains up to seven N Reactor fuel element assemblies. A gas space of nitrogen was established in the top 2.2 to 2.5 inches (5.6 to 6.4 cm) of each barrel. Many of the fuel elements were damaged allowing the metallic uranium fuel to be corroded by the canister water. The corrosion releases fission products and generates hydrogen gas. The released gas mixes with the gas-space gas and excess gas passes through the gas trap into the basin water. The canister design does not allow canister water to be exchanged with basin water.
Three-dimensional numerical models of the evolution of pull-apart basins
NASA Astrophysics Data System (ADS)
Petrunin, A. G.; Sobolev, S. V.
2008-12-01
Pull-apart basins are depressions that form as the result of crustal extension along strike-slip systems where the sense of fault stepping or bending coincides with that of fault slip. They are common features of strike-slip systems. We perform a number of numerical thermomechanical experiments to explore how the rheology of the lithosphere influences basin evolution and lithospheric structure beneath the basin. Our modeling shows that basin subsidence results from the competition of extension of the brittle part of the lithosphere, which leads to its subsidence, and of the compensating flow of the deeper ductile part of the lithosphere, which pushes the extended brittle block upwards. The result of this competition is the subsidence rate. Strain partitioning beneath the basin and crustal structures is controlled by (i) the thickness of the brittle layer and basin width, (ii) the magnitude of strike-slip displacement, (iii) the rate of frictional softening of the crust, and (iv) the viscosity of the ductile part of the lithosphere. The thickness of the brittle layer and the viscosity of the underlying ductile part of the lithosphere in turn depend on temperature, composition and material softening. We interpret the modeling results, deducing simple analytical expressions based on the "brittle brick stretching" (BBS) approach, which despite its simplicity describes the structure and evolution of pull-apart basins reasonably well. We also demonstrate that the structure and evolution of the Dead Sea Basin, located at a left step of the Dead Sea Transform in the Middle East, is consistent with a BBS type of deformation with only a minor contribution from compensational flow in the ductile part of the lithosphere. Finally, we show that the formation of a deep narrow pull-apart basin in relatively cold lithosphere, as in the Dead Sea Basin, requires very low friction at major faults (lower than 0.1-0.2). If this condition is not satisfied, strike-slip deformation does
Numerical Simulation of Petroleum Generation and Migration in the Song Hong Basin, Vietnam
NASA Astrophysics Data System (ADS)
Son, Byeong-Kook; Thi Nguyen, Hong; Park, Mee-Sook
2014-05-01
The numerical modeling of petroleum systems is an effective tool to understand generation, migration and accumulation of hydrocarbons in a sedimentary basin and hence to determine future targets for the hydrocarbon exploration. The numerical modeling identifies two petroleum systems in the Song Hong Basin, which is a petroliferous Cenozoic basin, offshore eastern Vietnam. These petroleum systems were named DinhCao-PhuCu(.) Petroleum System and SongHuong-BienDong(.) Petroleum System. DinhCao-PhuCu(.) Petroleum System covers northern and central parts of the Song Hong basin with Oligocene shale and coaly shale source rocks of Dinh Cao formation, which are dominated by type II-III kerogens. The hydrocarbon generation starts at 13 Ma within deeply buried Oligocene strata located in the centre of the basin. The hydrocarbon expels from the Oligocene source rock and migrates laterally and then up dip toward marginal areas where Middle Miocene sandstones of Phu Cu formation are present as major reservoirs. The numerical model shows that the critical moment occurs at about 3.5 Ma. The DinhCao-PhuCu(.) petroleum system is confirmed by sparse occurrence of oil and gas along the coast of eastern Vietnam. SongHuong-BienDong(.) Petroleum System is identified in limited areas of the central and southern Song Hong basin. The major source rock of this petroleum system is Lower Miocene dark claystones of Song Huong formation which contain gas prone, type III kerogen. The migration model shows that hydrocarbons are generated from the Miocene source rocks in the center of the basin at about 12 Ma, and migrates updip through sand bodies of Quang Ngai formation to the major boundaries faults, and further moves into highly permeable up-dipping units, the Bien Dong formation. The best depiction of the generation-migration-accumulation of hydrocarbons occurs at about 2 Ma. The presence of the SongHuong-BienDong(.) Petroleum System is indicated by the large gas fields in the central and
SE Great Basin Play Fairway Analysis
Adam Brandt
2015-11-15
This submission includes a Na/K geothermometer probability greater than 200 deg C map, as well as two play fairway analysis (PFA) models. The probability map acts as a composite risk segment for the PFA models. The PFA models differ in their application of magnetotelluric conductors as composite risk segments. These PFA models map out the geothermal potential in the region of SE Great Basin, Utah.
Numerical analysis of wave scattering
NASA Astrophysics Data System (ADS)
Beran, Mark J.
1994-12-01
The following topics were studied in detail during the report period: (1) Combined volume and surface scattering in a channel, using a modal formulation. (2) Two-way formulation to account for backscattering in a channel. (3) Data analysis to determine vertical and horizontal correlation lengths of the random index-of-refraction fluctuations in a channel. (4) The effect of random fluctuations on the two-frequency coherence function in a shallow channel. (5) Approximate eigenfunctions and eigenvalues for linear sound-speed profiles. (6) The effect of sea-water absorption on scattering in a shallow channel.
Basin analysis of South Mozambique graben
Iliffe, J.; Lerche, I.; De Buyl, M.
1987-05-01
Basin analysis of the South Mozambique graben between latitudes 25/sup 0/ and 26/sup 0/ and longitudes 34/sup 0/ and 35/sup 0/ demonstrates how modeling techniques may help to assess the oil potential of a speculative basin with only minimal seismic data. Two-dimensional restoration of the seismic profiles, using a backstripping and decompaction program on pseudowells linked with structural reconstruction, assesses the rift's two-phase extensional history. Since no well or thermal indicator data exist within the basin, the thermal history had to be derived from extensional models. The best fit of observed subsidence curves and those predicted by the models results in values of lithospheric extension (gamma). The disagreement in observed and theoretical basement subsidence curves was minimized by taking a range of gamma for each model for each well. These extension factors were then used in each model's equations for paleoheat flux to derive the heat-flow histories. (It is noted that a systematic basinwide variance of gamma occurs.) The heat-flux histories were then used with a one-dimensional fluid flow/compaction model to calculate TTI values and oil windows. A Tissot generation model was applied to each formation in every well for kerogen Types I, II, and III. The results were contoured across the basin to assess possible oil- and gas-prone formations. The extensional, burial, and thermal histories are integrated into an overall basin development picture and provide an oil and gas provenance model. Thus they estimate the basinwide hydrocarbon potential and also gain insight into the additional data necessary to significantly decrease the uncertainty.
NASA Astrophysics Data System (ADS)
Girou, O.; Lemieux, J. M.; Malo, M.
2015-12-01
Full-scale carbon capture and storage in deep saline aquifers implies injecting important quantities of carbon in order to significantly reduce greenhouse gases emissions. At the basin scale, impacts related to CO2 injection are pressure perturbation as well as brine migration into freshwater aquifers. In this study, potential impacts of an industrial-scale carbon capture and storage project in Bécancour (Quebec, Canada), in the St. Lawrence Lowlands basin, are discussed, as well as the role played by regional normal faults that divide the basin into multiple compartments. The basin is 300 km long and 90 km wide, formed by sub-horizontal Paleozoic formations on top of which the Utica and Lorraine shale formations represent the caprock of the potential CO2reservoir. These formations cover most of the basin, except in its eroded northwestern part, located between 10 to 40 km away from the potential injection sites. Three injection scenarios were considered, corresponding to greenhouse gases emissions from large emitters located; in Bécancour industrial park, in a larger area that allow affordable transport and in the entire basin without considering transport costs (1, 5, 10 Mt/yr). The numerical model FEFLOW was used to simulate CO2 injection into different compartments to evaluate pressure build up propagation and brine migration in order to define which compartments are best suited for long-term storage. The simulations considered an injection period of 100 years and post-injections period of 1000 years. Numerical simulations indicate that normal faults, which exhibit a low hydraulic conductivity, play a major role orienting pressure build-up and brine migration. Due to the presence of normal faults, no pressure build up occurred close to the surface. Similarly, preliminary mass transport simulations show very limited brine migration. These first results indicate that basin-scale impacts of carbon injection are low for the 3 injection scenarios, however, the
Simple Numerical Analysis of Longboard Speedometer Data
ERIC Educational Resources Information Center
Hare, Jonathan
2013-01-01
Simple numerical data analysis is described, using a standard spreadsheet program, to determine distance, velocity (speed) and acceleration from voltage data generated by a skateboard/longboard speedometer (Hare 2012 "Phys. Educ." 47 409-17). This simple analysis is an introduction to data processing including scaling data as well as…
Multivariate analysis of environmental data for two hydrographic basins
Andrade, J.M.; Prada, D.; Muniategui, S.; Gonzalez, E.; Alonso, E. )
1992-02-01
A multivariate study (PCA Analysis and Cluster analysis) of two Spanish hydrographic basins (The Mandeo and Mero basins) was made to achieve reliable conclusions about their actual physico-chemical environmental situation. Two police-samples' are defined, their effects explained, and are introduced in Cluster analysis as a way to examine sample quality. The multivariate analysis shows different qualities in the two hydrographic basins.
Numerical analysis of randomly forced glycolitic oscillations
Ryashko, Lev
2015-03-10
Randomly forced glycolytic oscillations in Higgins model are studied both numerically and analytically. Numerical analysis is based on the direct simulation of the solutions of stochastic system. Non-uniformity of the stochastic bundle along the deterministic cycle is shown. For the analytical investigation of the randomly forced Higgins model, the stochastic sensitivity function technique and confidence domains method are applied. Results of the influence of additive noise on the cycle of this model are given.
Numerical modeling of the ejecta distribution and formation of the Orientale basin on the Moon
NASA Astrophysics Data System (ADS)
Zhu, Meng-Hua; Wünnemann, Kai; Potter, Ross W. K.
2015-12-01
The formation and structure of the Orientale basin on the Moon has been extensively studied in the past; however, estimates of its transient crater size, excavated volume and depth, and ejecta distribution remain uncertain. Here we present a new numerical model to reinvestigate the formation and structure of Orientale basin and better constrain impact parameters such as impactor size and velocity. Unlike previous models, the observed ejecta distribution and ejecta thickness were used as the primary constraints to estimate transient crater size—the best measure of impact energy. Models were also compared to basin morphology and morphometry, and subsurface structures derived from high-resolution remote sensing observations and gravity data, respectively. The best fit model suggests a 100 km diameter impactor with a velocity of ~12 km s-1 formed the Orientale basin on a relatively "cold" Moon. In this impact scenario the transient crater diameter is ~400 km or 460 km depending on whether the crater is defined using the diameter of the excavation zone or the diameter of the growing cavity at the time of maximum crater volume, respectively. The volume of ejecta material is ~4.70 × 106 km3, in agreement with recent estimates of the Orientale ejecta blanket thickness from remote sensing studies. The model also confirms the remote sensing spectroscopic observations that no mantle material was excavated and deposited at Orientale's rim.
A.B. Gilliam; R.W.H. Carroll; G. Pohll; R.L. Hershey
2006-01-01
A detailed, transient, three-dimensional, finite-difference groundwater flow model was created for the Mercury Valley Administrative Groundwater Basin (MVB). The MVB is a distinct groundwater basin as defined by the State of Nevada and is located partially within the boundary of the Nevada Test Site. This basin is being studied as a potential location for new industrial facilities and therefore would be subject to Nevada water-use limitations. The MVB model was used to estimate the volume of water that could be withdrawn from Mercury Valley without inducing laterally or vertically extensive water-table effects. In each model simulation, water-table drawdown was limited to a maximum of 0.5 m at the boundary of the basin and held within the screened interval of the well. Water withdrawal from Nevada groundwater basins is also limited to the State-defined perennial yield for that area. The perennial yield for the MVB is 27,036 m{sup 3}/day. The one existing water-supply well in Mercury Valley is capable of sustaining significantly higher withdrawal rates than it currently produces. Simulations showed this single well could produce 50 percent of the basin?s perennial yield with limited water-table drawdown. Pumping from six hypothetical water-supply wells was also simulated. Each hypothetical well was placed in an area of high hydraulic conductivity and far from the basin's boundaries. Each of these wells was capable of producing at least 50 percent of the basin's perennial yield. One of the hypothetical wells could simulate 100 percent of the perennial yield while staying within drawdown limitations. Multi-well simulations where two or more water-supply wells were simultaneously pumping were also conducted. These simulations almost always resulted in very limited lateral and vertical drawdown and produced 100 percent of Mercury Valley's perennial yield. A water-budget analysis was also conducted for each of the various stress simulations. Each of the stress scenarios
Key Curriculum Reform Research on Numerical Analysis
NASA Astrophysics Data System (ADS)
Li, Zhong; Peng, Chensong
Based on the current undergraduate teaching characteristics and the actual teaching situation of numerical analysis curriculum, this paper gives a useful discussion and appropriate adjustments for this course's teaching content and style, and it also proposes some new curriculum reform plans to improve the teaching effectiveness which can develop student's abilities of mathematical thinking and computational practice.
Systems Improved Numerical Fluids Analysis Code
NASA Technical Reports Server (NTRS)
Costello, F. A.
1990-01-01
Systems Improved Numerical Fluids Analysis Code, SINFAC, consists of additional routines added to April, 1983, version of SINDA. Additional routines provide for mathematical modeling of active heat-transfer loops. Simulates steady-state and pseudo-transient operations of 16 different components of heat-transfer loops, including radiators, evaporators, condensers, mechanical pumps, reservoirs, and many types of valves and fittings. Program contains property-analysis routine used to compute thermodynamic properties of 20 different refrigerants. Source code written in FORTRAN 77.
NASA Astrophysics Data System (ADS)
Fernández, V.; Dietrich, D. E.; Haney, R. L.; Tintoré, J.
In situ and satellite data obtained during the last ten years have shown that the circula- tion in the Mediterranean Sea is extremely complex in space, with significant features ranging from mesoscale to sub-basin and basin scale, and highly variable in time, with mesoscale to seasonal and interannual signals. Also, the steep bottom topography and the variable atmospheric conditions from one sub-basin to another, make the circula- tion to be composed of numerous energetic and narrow coastal currents, density fronts and mesoscale structures that interact at sub-basin scale with the large scale circula- tion. To simulate numerically and better understand these features, besides high grid resolution, a low numerical dispersion and low physical dissipation ocean model is required. We present the results from a 1/8z horizontal resolution numerical simula- tion of the Mediterranean Sea using DieCAST ocean model, which meets the above requirements since it is stable with low general dissipation and uses accurate fourth- order-accurate approximations with low numerical dispersion. The simulations are carried out with climatological surface forcing using monthly mean winds and relax- ation towards climatological values of temperature and salinity. The model reproduces the main features of the large basin scale circulation, as well as the seasonal variabil- ity of sub-basin scale currents that are well documented by observations in straits and channels. In addition, DieCAST brings out natural fronts and eddies that usually do not appear in numerical simulations of the Mediterranean and that lead to a natural interannual variability. The role of this intrinsic variability in the general circulation will be discussed.
Manufacturing in space: Fluid dynamics numerical analysis
NASA Technical Reports Server (NTRS)
Robertson, S. J.; Nicholson, L. A.; Spradley, L. W.
1981-01-01
Natural convection in a spherical container with cooling at the center was numerically simulated using the Lockheed-developed General Interpolants Method (GIM) numerical fluid dynamic computer program. The numerical analysis was simplified by assuming axisymmetric flow in the spherical container, with the symmetry axis being a sphere diagonal parallel to the gravity vector. This axisymmetric spherical geometry was intended as an idealization of the proposed Lal/Kroes growing experiments to be performed on board Spacelab. Results were obtained for a range of Rayleigh numbers from 25 to 10,000. For a temperature difference of 10 C from the cooling sting at the center to the container surface, and a gravitional loading of 0.000001 g a computed maximum fluid velocity of about 2.4 x 0.00001 cm/sec was reached after about 250 sec. The computed velocities were found to be approximately proportional to the Rayleigh number over the range of Rayleigh numbers investigated.
Ferrofluids: Modeling, numerical analysis, and scientific computation
NASA Astrophysics Data System (ADS)
Tomas, Ignacio
This dissertation presents some developments in the Numerical Analysis of Partial Differential Equations (PDEs) describing the behavior of ferrofluids. The most widely accepted PDE model for ferrofluids is the Micropolar model proposed by R.E. Rosensweig. The Micropolar Navier-Stokes Equations (MNSE) is a subsystem of PDEs within the Rosensweig model. Being a simplified version of the much bigger system of PDEs proposed by Rosensweig, the MNSE are a natural starting point of this thesis. The MNSE couple linear velocity u, angular velocity w, and pressure p. We propose and analyze a first-order semi-implicit fully-discrete scheme for the MNSE, which decouples the computation of the linear and angular velocities, is unconditionally stable and delivers optimal convergence rates under assumptions analogous to those used for the Navier-Stokes equations. Moving onto the much more complex Rosensweig's model, we provide a definition (approximation) for the effective magnetizing field h, and explain the assumptions behind this definition. Unlike previous definitions available in the literature, this new definition is able to accommodate the effect of external magnetic fields. Using this definition we setup the system of PDEs coupling linear velocity u, pressure p, angular velocity w, magnetization m, and magnetic potential ϕ We show that this system is energy-stable and devise a numerical scheme that mimics the same stability property. We prove that solutions of the numerical scheme always exist and, under certain simplifying assumptions, that the discrete solutions converge. A notable outcome of the analysis of the numerical scheme for the Rosensweig's model is the choice of finite element spaces that allow the construction of an energy-stable scheme. Finally, with the lessons learned from Rosensweig's model, we develop a diffuse-interface model describing the behavior of two-phase ferrofluid flows and present an energy-stable numerical scheme for this model. For a
Numerical Analysis of Rocket Exhaust Cratering
NASA Technical Reports Server (NTRS)
2008-01-01
Supersonic jet exhaust impinging onto a flat surface is a fundamental flow encountered in space or with a missile launch vehicle system. The flow is important because it can endanger launch operations. The purpose of this study is to evaluate the effect of a landing rocket s exhaust on soils. From numerical simulations and analysis, we developed characteristic expressions and curves, which we can use, along with rocket nozzle performance, to predict cratering effects during a soft-soil landing. We conducted a series of multiphase flow simulations with two phases: exhaust gas and sand particles. The main objective of the simulation was to obtain the numerical results as close to the experimental results as possible. After several simulating test runs, the results showed that packing limit and the angle of internal friction are the two critical and dominant factors in the simulations.
Numerical analysis method for linear induction machines.
NASA Technical Reports Server (NTRS)
Elliott, D. G.
1972-01-01
A numerical analysis method has been developed for linear induction machines such as liquid metal MHD pumps and generators and linear motors. Arbitrary phase currents or voltages can be specified and the moving conductor can have arbitrary velocity and conductivity variations from point to point. The moving conductor is divided into a mesh and coefficients are calculated for the voltage induced at each mesh point by unit current at every other mesh point. Combining the coefficients with the mesh resistances yields a set of simultaneous equations which are solved for the unknown currents.
Numerical Analysis of Convection/Transpiration Cooling
NASA Technical Reports Server (NTRS)
Glass, David E.; Dilley, Arthur D.; Kelly, H. Neale
1999-01-01
An innovative concept utilizing the natural porosity of refractory-composite materials and hydrogen coolant to provide CONvective and TRANspiration (CONTRAN) cooling and oxidation protection has been numerically studied for surfaces exposed to a high heat flux high temperature environment such as hypersonic vehicle engine combustor walls. A boundary layer code and a porous media finite difference code were utilized to analyze the effect of convection and transpiration cooling on surface heat flux and temperature. The boundary layer code determined that transpiration flow is able to provide blocking of the surface heat flux only if it is above a minimum level due to heat addition from combustion of the hydrogen transpirant. The porous media analysis indicated that cooling of the surface is attained with coolant flow rates that are in the same range as those required for blocking, indicating that a coupled analysis would be beneficial.
Numerical Analysis of Convection/Transpiration Cooling
NASA Technical Reports Server (NTRS)
Glass, David E.; Dilley, Arthur D.; Kelly, H. Neale
1999-01-01
An innovative concept utilizing the natural porosity of refractory-composite materials and hydrogen coolant to provide CONvective and TRANspiration (CONTRAN) cooling and oxidation protection has been numerically studied for surfaces exposed to a high heat flux, high temperature environment such as hypersonic vehicle engine combustor walls. A boundary layer code and a porous media finite difference code were utilized to analyze the effect of convection and transpiration cooling on surface heat flux and temperature. The boundary, layer code determined that transpiration flow is able to provide blocking of the surface heat flux only if it is above a minimum level due to heat addition from combustion of the hydrogen transpirant. The porous media analysis indicated that cooling of the surface is attained with coolant flow rates that are in the same range as those required for blocking, indicating that a coupled analysis would be beneficial.
Three Dimensional Numerical Analysis on Discharge Properties
NASA Astrophysics Data System (ADS)
Takaishi, Kenji; Katsurai, Makoto
2003-10-01
A three dimensional simulation code with the finite difference time domain (FDTD) method combined with the two fluids model for electron and ion has been developed for the microwave excited surface wave plasma in the RDL-SWP device. This code permits the numerical analysis of the spatial distributions of electric field, power absorption, electron density and electron temperature. At low gas pressure of about 10 mTorr, the numerical results compared with the experimental measurements that shows the validity of this 3-D simulation code. A simplified analysis assuming that an electron density is spatially uniform has been studied and its applicability is evaluated by 3-D simulation. The surface wave eigenmodes are determined by electron density, and it is found that the structure of the device strongly influences to the spatial distribution of the electric fields of surface wave in a low density area. A method to irradiate a microwave to the whole surface area of the plasma is proposed which is found to be effective to obtain a high uniformity distribution of electron density.
A theoretical analysis of basin-scale groundwater temperature distribution
NASA Astrophysics Data System (ADS)
An, Ran; Jiang, Xiao-Wei; Wang, Jun-Zhi; Wan, Li; Wang, Xu-Sheng; Li, Hailong
2015-03-01
The theory of regional groundwater flow is critical for explaining heat transport by moving groundwater in basins. Domenico and Palciauskas's (1973) pioneering study on convective heat transport in a simple basin assumed that convection has a small influence on redistributing groundwater temperature. Moreover, there has been no research focused on the temperature distribution around stagnation zones among flow systems. In this paper, the temperature distribution in the simple basin is reexamined and that in a complex basin with nested flow systems is explored. In both basins, compared to the temperature distribution due to conduction, convection leads to a lower temperature in most parts of the basin except for a small part near the discharge area. There is a high-temperature anomaly around the basin-bottom stagnation point where two flow systems converge due to a low degree of convection and a long travel distance, but there is no anomaly around the basin-bottom stagnation point where two flow systems diverge. In the complex basin, there are also high-temperature anomalies around internal stagnation points. Temperature around internal stagnation points could be very high when they are close to the basin bottom, for example, due to the small permeability anisotropy ratio. The temperature distribution revealed in this study could be valuable when using heat as a tracer to identify the pattern of groundwater flow in large-scale basins. Domenico PA, Palciauskas VV (1973) Theoretical analysis of forced convective heat transfer in regional groundwater flow. Geological Society of America Bulletin 84:3803-3814
Numerical analysis of flows in reciprocating engines
NASA Astrophysics Data System (ADS)
Takata, H.; Kojima, M.
1986-07-01
A numerical method of the analysis for three-dimensional turbulent flow in cylinders of reciprocating engines with arbitrary geometry is described. A scheme of the finite volume/finite element methods is used, employing a large number of small elements of arbitrary shapes to form a cylinder. The fluid dynamic equations are expressed in integral form for each element, taking into account the deformation of the element shape according to the piston movements, and are solved in the physical space using rectangular coordinates. The conventional k-epsilon two-equation model is employed to describe the flow turbulence. Example calculations are presented for simple pancake-type combustion chambers having an annular intake port at either center or asymmetric position of the cylinder head. The suction inflow direction is also changed in several ways. The results show a good simulation of overall fluid movements within the engine cylinder.
The DESIRE Airborne gravity project in the Dead Sea Basin and 3D numerical gravity modeling
NASA Astrophysics Data System (ADS)
Choi, S.; Goetze, H.; Meyer, U.; Group, D.
2008-12-01
This geo-scientific research focuses on the geological setting of the Dead Sea Transform (DST) and the Dead Sea Basin (DSB) and its resulting pull-apart basins. Since the late 1970s, crustal scale geophysical experiments have been carried out in this region. However, the nature of the crust underlying the eastern and western shoulders of the DSB and underneath the DST itself is still a hotly debated topic among researchers. To address one of the central questions of plate tectonics - How do large transform systems work and what are their typical features? - An international geoscientific Dead Sea Integrated Research project (DESIRE) is being conducted by colleagues from Germany, Israel, Palestine, and Jordan. In order to provide a high resolution gravity database that support 3D numerical modeling and hence a more comprehensive understanding of the nature and segmentation of the DST, an airborne gravity survey as a part of the DESIRE project has been carried out from February to March 2007. The airborne gravity survey covered the DST from Elat/Aqaba in the South to the northern rim of the Dead Sea. The low speed and terrain-following helicopter gravity flights were performed to acquire the highest possible data quality. In total, 32 north-south profiles and 16 west-east profiles crossing the DST have been measured. Most of the profiles concentrated in areas that lacked terrestrial gravity data coverage, e. g. over the shoulders of the DSB. The airborne gravity data are merged with existing conventional (terrestrial) data sets to provide a seamless gravity map of the area of interest. Using that combined gravity dataset and DESIRE wide angle refractions seismic interpretation we modified density structures in the DSB. As results we estimated that (1) the Moho depth varies from 26 km in the Israel side to 34 km in the Jordan side. (2) The maximum thickness of the Dead Sea sediment Basin is about 15 km. (3) The salt rock with an average thickness of about 5 km is
183-H Basin Mixed Waste Analysis and Testing Report
1995-04-01
The purpose of this sampling and analysis report is to provide data necessary to support treatment and disposal options for the low-level mixed waste from the 183-H solar evaporation ponds. In 1973, four of the 16 flocculation and sedimentation basins were designated for use as solar evaporation basins to provide waste reduction by natural evaporation of liquid chemical wastes from the 300 Area fuel fabrication facilities. The primary purpose of this effort is to gather chemical and bulk property data for the waste in the drums/boxes of sediment removed from the basin at Central Waste Complex.
Tularosa Basin Play Fairway Analysis: Water Chemistry
Adam Brandt
2015-12-15
This shapefile contains 409 well data points on Tularosa Basin Water Chemistry, each of which have a location (UTM), temperature, quartz and Potassium/Magnesium geothermometer; as well as concentrations of chemicals like Mn, Fe, Ba, Sr, Cs, Rb, As, NH4, HCO3, SO4, F, Cl, B, SiO2, Mg, Ca, K, Na, and Li.
Two numerical models for landslide dynamic analysis
NASA Astrophysics Data System (ADS)
Hungr, Oldrich; McDougall, Scott
2009-05-01
Two microcomputer-based numerical models (Dynamic ANalysis (DAN) and three-dimensional model DAN (DAN3D)) have been developed and extensively used for analysis of landslide runout, specifically for the purposes of practical landslide hazard and risk assessment. The theoretical basis of both models is a system of depth-averaged governing equations derived from the principles of continuum mechanics. Original features developed specifically during this work include: an open rheological kernel; explicit use of tangential strain to determine the tangential stress state within the flowing sheet, which is both more realistic and beneficial to the stability of the model; orientation of principal tangential stresses parallel with the direction of motion; inclusion of the centripetal forces corresponding to the true curvature of the path in the motion direction and; the use of very simple and highly efficient free surface interpolation methods. Both models yield similar results when applied to the same sets of input data. Both algorithms are designed to work within the semi-empirical framework of the "equivalent fluid" approach. This approach requires selection of material rheology and calibration of input parameters through back-analysis of real events. Although approximate, it facilitates simple and efficient operation while accounting for the most important characteristics of extremely rapid landslides. The two models have been verified against several controlled laboratory experiments with known physical basis. A large number of back-analyses of real landslides of various types have also been carried out. One example is presented. Calibration patterns are emerging, which give a promise of predictive capability.
Neotectonics of the Surma Basin, Bangladesh from GPS analysis
NASA Astrophysics Data System (ADS)
Bulbul, M. A. U.
2015-12-01
The Surma Basin is a sub-basin of the Bengal Basin situated at the northeastern corner of Bangladesh. The tectonically-active basin lies at the junction of three tectonic plates: the Indian plate, the Eurasian plate and the Burma platelet. The Surma Basin is bounded on the north by the Shillong Massif, east and southeast by CTFB of the Indo-Burman Ranges, west by the Indian Shield and to the south and southeast it is open to the main part of Bengal Basin. The Surma basin is subsiding at a high rate, which is controlled by flexure loading along the southern margin of the 2-km high Shillong Massif because of Dauki thrust fault system. The objective of this study is to explore and reconstruct the present scenario of the tectonically active zone of the northeastern Bangladesh, identify the active faults, identify the relation between the neotectonic activities and seismicity, relation between neotectonic activities and natural hazards and describe the nature of the possible future earthquakes. The present effort to establish the tectonics of the Surma basin mainly utilizes the horizontal and vertical movements of the area using GPS geodetic data and other constraints on the structure of the region. We also make use historical seismologic data, field geology, and satellite image data. The GPS data has been processed using GAMIT-GLOBK. The analysis of 5 continuous GPS geodetic stations installed in the Surma Basin are combined with published data from the adjacent parts of India. While the area is moving northeast at a rate of 50-52 mm/year relative to ITRF2008 reference frame, it is moving south in an Indian reference frame. The velocities reflect that the Surma Basin being overthrust by both Shillong Plateau from the north and Burmese microplate from the east, respectively. The combined GPS velocity data indicates shortening across Dauki Fault and Indo Burman Ranges at a rate of 7 mm/yr and 18 mm/yr, respectively. The complex anticlinal structures in and around the
Sedimentary basin analysis using airborne gravity data: a case study from the Bohai Bay Basin, China
NASA Astrophysics Data System (ADS)
Li, Wenyong; Liu, Yanxu; Zhou, Jianxin; Zhou, Xihua; Li, Bing
2015-12-01
In this paper, we discuss the application of an airborne gravity survey to sedimentary basin analysis. Using high-precision airborne gravity data constrained by drilling and seismic data from the Bohai Bay Basin in eastern China, we interpreted faults, structural elements, sedimentary thickness, structural styles and local structures (belts) in the central area of the Basin by the wavelet transform method. Subsequently, these data were subtracted from the Bouguer gravity to calculate the residual gravity anomalies. On this basis, the faults were interpreted mainly by linear zones of high gravity gradients and contour distortion, while the sedimentary thicknesses were computed by the Euler deconvolution. The structural styles were identified by the combination of gravity anomalies and the local structures interpreted by the first vertical derivative of the residual gravity. The results showed evidence for seven faults, one sag and ten new local structure belts.
Nonclassicality thresholds for multiqubit states: Numerical analysis
Gruca, Jacek; Zukowski, Marek; Laskowski, Wieslaw; Kiesel, Nikolai; Wieczorek, Witlef; Weinfurter, Harald; Schmid, Christian
2010-07-15
States that strongly violate Bell's inequalities are required in many quantum-informational protocols as, for example, in cryptography, secret sharing, and the reduction of communication complexity. We investigate families of such states with a numerical method which allows us to reveal nonclassicality even without direct knowledge of Bell's inequalities for the given problem. An extensive set of numerical results is presented and discussed.
Numerical Simulation of Ground-Water Withdrawals in the Southern Lihue Basin, Kauai, Hawaii
Izuka, Scot K.; Oki, Delwyn S.
2002-01-01
Numerical simulations indicate that ground-water withdrawals from the Hanamaulu and Puhi areas of the southern Lihue Basin will result in a decline in water levels and reductions in base flows of streams near proposed new water-supply wells. Most of the changes will be attained within 10 to 20 years of the start of pumping. Except for areas such as Puhi and Kilohana, the freshwater lens in most inland areas of the southern Lihue Basin is thick and model simulations indicate that changes in water level and the position of the freshwater- saltwater interface in response to pumping will be small relative to the present thickness of the freshwater lens. Effects of the proposed withdrawals on streamflow depend on withdrawal rate and proximity of the wells to streams. Placing pumped wells away from streams with low base flow and toward streams with high base flow can reduce the relative effect on individual streams. Simulation of the 0.42-million-gallon-per-day increase in withdrawal projected for 2000 indicates that the resulting changes in water levels and interface position, relative to conditions prior to the withdrawal increase, will be small, and that stream base flow will be reduced by less than 10 percent. Simulation of the 0.83-million-gallon-per-day withdrawal projected for 2010 indicates further thinning of the freshwater lens in the Puhi area, where the lens already may be thin, as well as base-flow reduction in Nawiliwili Stream. Simulation of an alternative distribution of the 0.83-million-gallon-per-day withdrawal indicates that the effects can be reduced by shifting most of the new withdrawal to the Hanamaulu area where the freshwater lens is thicker and stream base flows are greater. Simulation of the 1.16-million-gallon-per-day increase in withdrawal projected for 2020 indicates that if withdrawal is distributed only among Hana-maulu wells 1, 3, and 4, and Puhi well 5A, further thinning of the already-thin freshwater lens in the Puhi area would occur
NASA Astrophysics Data System (ADS)
Gardner, W. Payton; Susong, David D.; Solomon, D. Kip; Heasler, Henry P.
2013-06-01
Heat and fluid flow fields are simulated for several conceptual permeability fields and compared to processes inferred from environmental tracers in springs around Norris Geyser Basin, Yellowstone National Park. Large hydrothermal basins require specific permeability distributions in the upper crust. High permeability connections must exist between the land surface and high-temperature environments at depths of up to 5 km. The highest modeled temperatures are produced with a vertical conduit permeability of 10-15m2. Permeability at depths of 3-5 km must be within one order of magnitude of the near-surface permeability and must be ≥10-16m2. Environmental tracers from springs are used to develop a plausible numerical model of the local to regional groundwater flow field for the Norris Geyser Basin area. The model simulations provide insight into the dynamics of heat and fluid flow in a large regional hydrothermal system.
NASA Astrophysics Data System (ADS)
Cédric, Guyonnet-Benaize; Fabrice, Hollender; Maria, Manakou; Alexandros, Savvaidis; Elena, Zargli; Cécile, Cornou; Nikolaos, Veranis; Dimitrios, Raptakis; Artemios, Atzemoglou; Pierre-Yves, Bard; Nikolaos, Theodulidis; Kyriazis, Pitilakis; Emmanuelle, Chaljub
2013-04-01
The Mygdonian basin, located 30 km E-NE close to Thessaloniki, is a typical active tectonic basin, trending E-NW, filled by sediments 200 to 400 m thick. This basin has been chosen as a European experimental site since 1993 (European Commission research projects - EUROSEISTEST). It has been investigated for experimental and theoretical studies on site effects. The Mygdonian basin is currently covered by a permanent seismological network and has been mainly characterized in 2D and 3D with geophysical and geotechnical studies (Bastani et al, 2011; Cadet and Savvaidis, 2011; Gurk et al, 2007; Manakou et al, 2007; Manakou et al, 2010; Pitilakis et al, 1999; Raptakis et al, 2000; Raptakis et al, 2005). All these studies allowed understanding the influence of geological structures and local site conditions on seismic site response. For these reasons, this site has been chosen for a verification exercise for numerical simulations in the framework of an ongoing international collaborative research project (Euroseistest Verification and Validation Project - E2VP). The verification phase has been made using a first 3D geophysical and geotechnical model (Manakou, 2007) about 5 km wide and 15 km long, centered on the Euroseistest site. After this verification phase, it has been decided to update, optimize and extend this model in order to obtain a more detailed model of the 3D geometry of the entire basin, especially the bedrock 3D geometry which can affect drastically the results of numerical simulations for site effect studies. In our study, we build a 3D geological model of the present-day structure of the entire Mygdonian basin. This "precise" model is 12 km wide, 65 km long and is 400 m deep in average. It has been built using geophysical, geotechnical and geological data. The database is heterogeneous and composed of hydrogeological boreholes, seismic refraction surveys, array microtremor measurements, electrical and geotechnical surveys. We propose an integrated
Numerical analysis and measurement in corner-fired furnace
Zhengjun, S.; Rongsheng, G.
1999-07-01
For several years, numerical analysis has been successfully used by Dongfang Boiler (Group) Co., Ltd. at a 200MW boiler, a 300MW boiler and so on, which were designed and made by DBC. The distribution of results is agreement each other between numerical analysis and measurement. In conclusion, it is considered that numerical analysis can be used as an important reference method in pulverized coal boiler design and test.
Numerical analysis of granular soil fabrics
NASA Astrophysics Data System (ADS)
Torbahn, L.; Huhn, K.
2012-04-01
Soil stability strongly depends on the material strength that is in general influenced by deformation processes and vice versa. Hence, investigation of material strength is of great interest in many geoscientific studies where soil deformations occur, e.g. the destabilization of slopes or the evolution of fault gouges. Particularly in the former case, slope failure occurs if the applied forces exceed the shear strength of slope material. Hence, the soil resistance or respectively the material strength acts contrary to deformation processes. Besides, geotechnical experiments, e.g. direct shear or ring shear tests, suggest that shear resistance mainly depends on properties of soil structure, texture and fabric. Although laboratory tests enable investigations of soil structure and texture during shear, detailed observations inside the sheared specimen during the failure processes as well as fabric effects are very limited. So, high-resolution information in space and time regarding texture evolution and/or grain behavior during shear is refused. However, such data is essential to gain a deeper insight into the key role of soil structure, texture, etc. on material strength and the physical processes occurring during material deformation on a micro-scaled level. Additionally, laboratory tests are not completely reproducible enabling a detailed statistical investigation of fabric during shear. So, almost identical setups to run methodical tests investigating the impact of fabric on soil resistance are hard to archive under laboratory conditions. Hence, we used numerical shear test experiments utilizing the Discrete Element Method to quantify the impact of different material fabrics on the shear resistance of soil as this granular model approach enables to investigate failure processes on a grain-scaled level. Our numerical setup adapts general settings from laboratory tests while the model characteristics are fixed except for the soil structure particularly the used
Morphometric analysis of the Marmara Sea river basins, Turkey
NASA Astrophysics Data System (ADS)
Elbaşı, Emre; Ozdemir, Hasan
2014-05-01
The drainage basin, the fundamental unit of the fluvial landscape, has been focus of research aimed at understanding the geometric characteristics of the master channel and its tributary network. This geometry is referred to as the basin morphometry and is nicely reviewed by Abrahams (1984). A great amount of research has focused on geometric characteristic of drainage basins, including the topology of the stream networks, and quantitative description of drainage texture, pattern, shape, and relief characteristics. Evaluation of morphometric parameters necessitates the analysis of various drainage parameters such as ordering of the various streams, measurement of basin area and perimeter, length of drainage channels, drainage density (Dd), stream frequency (Fs), bifurcation ratio (Rb), texture ratio (T), basin relief (Bh), Ruggedness number (Rn), time of concentration (Tc), hypsometric curve and integral (Hc and Hi) (Horton, 1932, Schumn, 1956, Strahler, 1957; Verstappen 1983; Keller and Pinter, 2002; Ozdemir and Bird, 2009). These morphometric parameters have generally been used to predict flood peaks, to assess sediment yield, and to estimate erosion rates in the basins. River basins of the Marmara Sea, has an area of approximately 40,000 sqkm, are the most important basins in Turkey based on their dense populations, industry and transportation systems. The primary aim of this study is to determine and analyse of morphometric characteristics of the Marmara Sea river basins using 10 m resolution Digital Elevation Model (DEM) and to evaluate of the results. For these purposes, digital 10 m contour maps scaled 1:25000 and geological maps scaled 1:100000 were used as the main data sources in the study. 10 m resolution DEM data were created using the contour maps and then drainage networks and their watersheds were extracted using D8 pour point model. Finally, linear, areal and relief morphometries were applied to the river basins using Geographic Information Systems
NASA Astrophysics Data System (ADS)
Niu, Jun; Chen, Ji; Sun, Liqun
2015-07-01
The knowledge of drought evolution characteristics may aid the decision making process in mitigating drought impacts. This study uses a macro-scale hydrological model, Variable Infiltration Capacity (VIC) model, to simulate terrestrial hydrological processes over the Xijiang (West River) basin in South China. Three drought indices, namely standardized precipitation index (SPI), standardized runoff index (SRI), and soil moisture anomaly index (SMAI), are employed to examine the spatio-temporal and evolution features of drought events. SPI, SRI and SMAI represent meteorological drought, hydrological drought and agricultural drought, respectively. The results reveal that the drought severity depicted by SPI and SRI is similar with increasing timescales; SRI is close to that of SPI in the wet season for the Liu River basin as the high-frequency precipitation is conserved more by runoff; the time lags appear between SPI and SRI due to the delay response of runoff to precipitation variability for the You River basin. The case study in 2010 spring drought further shows that the spatio-temporal evolutions are modulated by the basin-scale topography. There is more consistency between meteorological and hydrological droughts for the fan-like basin with a converged river network. For the west area of the Xijiang basin with the high elevation, the hydrological drought severity is less than meteorological drought during the developing stage. The recovery of hydrological and agricultural droughts is slower than that of meteorological drought for basins with a longer mainstream.
SINFAC - SYSTEMS IMPROVED NUMERICAL FLUIDS ANALYSIS CODE
NASA Technical Reports Server (NTRS)
Costello, F. A.
1994-01-01
The Systems Improved Numerical Fluids Analysis Code, SINFAC, consists of additional routines added to the April 1983 revision of SINDA, a general thermal analyzer program. The purpose of the additional routines is to allow for the modeling of active heat transfer loops. The modeler can simulate the steady-state and pseudo-transient operations of 16 different heat transfer loop components including radiators, evaporators, condensers, mechanical pumps, reservoirs and many types of valves and fittings. In addition, the program contains a property analysis routine that can be used to compute the thermodynamic properties of 20 different refrigerants. SINFAC can simulate the response to transient boundary conditions. SINFAC was first developed as a method for computing the steady-state performance of two phase systems. It was then modified using CNFRWD, SINDA's explicit time-integration scheme, to accommodate transient thermal models. However, SINFAC cannot simulate pressure drops due to time-dependent fluid acceleration, transient boil-out, or transient fill-up, except in the accumulator. SINFAC also requires the user to be familiar with SINDA. The solution procedure used by SINFAC is similar to that which an engineer would use to solve a system manually. The solution to a system requires the determination of all of the outlet conditions of each component such as the flow rate, pressure, and enthalpy. To obtain these values, the user first estimates the inlet conditions to the first component of the system, then computes the outlet conditions from the data supplied by the manufacturer of the first component. The user then estimates the temperature at the outlet of the third component and computes the corresponding flow resistance of the second component. With the flow resistance of the second component, the user computes the conditions down stream, namely the inlet conditions of the third. The computations follow for the rest of the system, back to the first component
Fractal Analysis of Drainage Basins on Mars
NASA Technical Reports Server (NTRS)
Stepinski, T. F.; Marinova, M. M.; McGovern, P. J.; Clifford, S. M.
2002-01-01
We used statistical properties of drainage networks on Mars as a measure of martian landscape morphology and an indicator of landscape evolution processes. We utilize the Mars Orbiter Laser Altimeter (MOLA) data to construct digital elevation maps (DEMs) of several, mostly ancient, martian terrains. Drainage basins and channel networks are computationally extracted from DEMs and their structures are analyzed and compared to drainage networks extracted from terrestrial and lunar DEMs. We show that martian networks are self-affine statistical fractals with planar properties similar to terrestrial networks, but vertical properties similar to lunar networks. The uniformity of martian drainage density is between those for terrestrial and lunar landscapes. Our results are consistent with the roughening of ancient martian terrains by combination of rainfall-fed erosion and impacts, although roughening by other fluvial processes cannot be excluded. The notion of sustained rainfall in recent Mars history is inconsistent with our findings.
Numerical likelihood analysis of cosmic ray anisotropies
Carlos Hojvat et al.
2003-07-02
A numerical likelihood approach to the determination of cosmic ray anisotropies is presented which offers many advantages over other approaches. It allows a wide range of statistically meaningful hypotheses to be compared even when full sky coverage is unavailable, can be readily extended in order to include measurement errors, and makes maximum unbiased use of all available information.
Tularosa Basin Play Fairway Analysis: Methodology Flow Charts
Adam Brandt
2015-11-15
These images show the comprehensive methodology used for creation of a Play Fairway Analysis to explore the geothermal resource potential of the Tularosa Basin, New Mexico. The deterministic methodology was originated by the petroleum industry, but was custom-modified to function as a knowledge-based geothermal exploration tool. The stochastic PFA flow chart uses weights of evidence, and is data-driven.
Application of Sediment Backstripping Corrections for Basin Analysis Using Microcomputers.
ERIC Educational Resources Information Center
Wilkerson, Marlon Scott; Hsui, Albert Tong-Kwan
1989-01-01
Discussed is a program created to serve as an instructional tool for teaching basin analysis. Described is the use of the program for interpreting plots resulting from backstripping methods. Included in the discussion are implementation, applications and availability of the "Subside!" program. (CW)
A Numerical Model for Atomtronic Circuit Analysis
Chow, Weng W.; Straatsma, Cameron J. E.; Anderson, Dana Z.
2015-07-16
A model for studying atomtronic devices and circuits based on finite-temperature Bose-condensed gases is presented. The approach involves numerically solving equations of motion for atomic populations and coherences, derived using the Bose-Hubbard Hamiltonian and the Heisenberg picture. The resulting cluster expansion is truncated at a level giving balance between physics rigor and numerical demand mitigation. This approach allows parametric studies involving time scales that cover both the rapid population dynamics relevant to nonequilibrium state evolution, as well as the much longer time durations typical for reaching steady-state device operation. This model is demonstrated by studying the evolution of a Bose-condensed gas in the presence of atom injection and extraction in a double-well potential. In this configuration phase locking between condensates in each well of the potential is readily observed, and its influence on the evolution of the system is studied.
Numerical model for atomtronic circuit analysis
NASA Astrophysics Data System (ADS)
Chow, Weng W.; Straatsma, Cameron J. E.; Anderson, Dana Z.
2015-07-01
A model for studying atomtronic devices and circuits based on finite-temperature Bose-condensed gases is presented. The approach involves numerically solving equations of motion for atomic populations and coherences, derived using the Bose-Hubbard Hamiltonian and the Heisenberg picture. The resulting cluster expansion is truncated at a level giving balance between physics rigor and numerical demand mitigation. This approach allows parametric studies involving time scales that cover both the rapid population dynamics relevant to nonequilibrium state evolution, as well as the much longer time durations typical for reaching steady-state device operation. The model is demonstrated by studying the evolution of a Bose-condensed gas in the presence of atom injection and extraction in a double-well potential. In this configuration phase locking between condensates in each well of the potential is readily observed, and its influence on the evolution of the system is studied.
Numerical Analysis of the SCHOLAR Supersonic Combustor
NASA Technical Reports Server (NTRS)
Rodriguez, Carlos G.; Cutler, Andrew D.
2003-01-01
The SCHOLAR scramjet experiment is the subject of an ongoing numerical investigation. The facility nozzle and combustor were solved separate and sequentially, with the exit conditions of the former used as inlet conditions for the latter. A baseline configuration for the numerical model was compared with the available experimental data. It was found that ignition-delay was underpredicted and fuel-plume penetration overpredicted, while the pressure rise was close to experimental values. In addition, grid-convergence by means of grid-sequencing could not be established. The effects of the different turbulence parameters were quantified. It was found that it was not possible to simultaneously predict the three main parameters of this flow: pressure-rise, ignition-delay, and fuel-plume penetration.
Numerical Analysis of Robust Phase Estimation
NASA Astrophysics Data System (ADS)
Rudinger, Kenneth; Kimmel, Shelby
Robust phase estimation (RPE) is a new technique for estimating rotation angles and axes of single-qubit operations, steps necessary for developing useful quantum gates [arXiv:1502.02677]. As RPE only diagnoses a few parameters of a set of gate operations while at the same time achieving Heisenberg scaling, it requires relatively few resources compared to traditional tomographic procedures. In this talk, we present numerical simulations of RPE that show both Heisenberg scaling and robustness against state preparation and measurement errors, while also demonstrating numerical bounds on the procedure's efficacy. We additionally compare RPE to gate set tomography (GST), another Heisenberg-limited tomographic procedure. While GST provides a full gate set description, it is more resource-intensive than RPE, leading to potential tradeoffs between the procedures. We explore these tradeoffs and numerically establish criteria to guide experimentalists in deciding when to use RPE or GST to characterize their gate sets.Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.
Analysis of single ring infiltrometer test by direct numerical modeling
NASA Astrophysics Data System (ADS)
Réfloch, Aurore; Oxarango, Laurent; Rossier, Yvan; Gaudet, Jean Paul
2016-04-01
The well field of the Lyon metropolitan area provides drinking water to approximately 1,300,000 inhabitants. It is equipped with 12 infiltration basins. These basins have two main goals: sustaining the water table in times of peak demand for water, and preventing a possible contamination from the Rhône river by inverting groundwater flow direction. The water infiltration under the basins is thus crucial for the overall hydrogeologic behavior of the site. In order to characterize this phenomenon, a set of infiltrometer tests were performed to estimate the soil hydraulic properties. The soil is a coarse alluvial deposits. In order to deal with its sparse granulometric curve, a large single ring infiltrometer (1 meter in diameter) was used. A constant hydraulic head (=0.07 m) was imposed during the test. Two kinds of data are recorded: the amount of water infiltrated over time and the extension of the moisture stain around the ring. The main hydraulic properties are estimated using Richard's equation in a 2D axi-symmetric configuration. Simulations are performed using a finite element commercial software package (Comsol Multiphysics 5.1). According to simplified numerical models, an average homogeneous saturated permeability of the alluvial deposits is estimated at 5.0 10-6 m.s-1. However, such a simple model is not able to represent accurately the moisture stain at the soil surface. More complex models introduce anisotropy of permeability in the alluvium layer, with mono or bi-layer domain. In these cases, experimental and modeling results are consistent, both for the amount of water infiltrated over time and the extension of the moisture stain around the ring. The hydraulic anisotropy in the soil could be due to the stratified nature of alluvial deposits and to soil compaction during the construction of infiltration basins. Keywords: Single ring infiltrometer test, artificial aquifer recharge, numerical modeling.
NASA Astrophysics Data System (ADS)
Benaïchouche, Abed; Stab, Olivier; Tessier, Bruno; Cojan, Isabelle
2016-01-01
In landscapes dominated by fluvial erosion, the landscape morphology is closely related to the hydrographic network system. In this paper, we investigate the hydrographic network reorganization caused by a headward piracy mechanism between two drainage basins in France, the Meuse and the Moselle. Several piracies occurred in the Meuse basin during the past one million years, and the basin's current characteristics are favorable to new piracies by the Moselle river network. This study evaluates the consequences over the next several million years of a relative lowering of the Moselle River (and thus of its basin) with respect to the Meuse River. The problem is addressed with a numerical modeling approach (landscape evolution model, hereafter LEM) that requires empirical determinations of parameters and threshold values. Classically, fitting of the parameters is based on analysis of the relationship between the slope and the drainage area and is conducted under the hypothesis of equilibrium. Application of this conventional approach to the capture issue yields incomplete results that have been consolidated by a parametric sensitivity analysis. The LEM equations give a six-dimensional parameter space that was explored with over 15,000 simulations using the landscape evolution model GOLEM. The results demonstrate that stream piracies occur in only four locations in the studied reach near the city of Toul. The locations are mainly controlled by the local topography and are model-independent. Nevertheless, the chronology of the captures depends on two parameters: the river concavity (given by the fluvial advection equation) and the hillslope erosion factor. Thus, the simulations lead to three different scenarios that are explained by a phenomenon of exclusion or a string of events.
Ernest A. Mancini; Paul Aharon; Donald A. Goddard; Roger Barnaby
2006-02-28
The principal research effort for Year 3 of the project is basin modeling and petroleum system identification, comparative basin evaluation and resource assessment. In the first six (6) months of Year 3, the research focus is on basin modeling and petroleum system identification and the remainder of the year the emphasis is on the comparative basin evaluation and resource assessment. No major problems have been encountered to date, and the project is on schedule. The principal objectives of the project are to develop through basin analysis and modeling the concept that petroleum systems acting in a basin can be identified through basin modeling and to demonstrate that the information and analysis resulting from characterizing and modeling of these petroleum systems in the North Louisiana Salt Basin and the Mississippi Interior Salt Basin can be used in providing a more reliable and advanced approach for targeting stratigraphic traps and specific reservoir facies within a geologic system and in providing a refined assessment of undiscovered and underdeveloped reservoirs and associated oil and gas resources.
Numerical Analysis of the Symmetric Methods
NASA Astrophysics Data System (ADS)
Xu, Ji-Hong; Zhang, A.-Li
1995-03-01
Aimed at the initial value problem of the particular second-order ordinary differential equations,y ″=f(x, y), the symmetric methods (Quinlan and Tremaine, 1990) and our methods (Xu and Zhang, 1994) have been compared in detail by integrating the artificial earth satellite orbits in this paper. In the end, we point out clearly that the integral accuracy of numerical integration of the satellite orbits by applying our methods is obviously higher than that by applying the same order formula of the symmetric methods when the integration time-interval is not greater than 12000 periods.
NASA Astrophysics Data System (ADS)
Zodiatis, George; Radhakrishnan, Hari; Lardner, Robin; Hayes, Daniel; Gertman, Isaac; Menna, Milena; Poulain, Pierre-Marie
2014-05-01
The general anticlockwise circulation along the coastline of the Eastern Mediterranean Levantine Basin was first proposed by Nielsen in 1912. Half a century later the schematic of the circulation in the area was enriched with sub-basin flow structures. In late 1980s, a more detailed picture of the circulation composed of eddies, gyres and coastal-offshore jets was defined during the POEM cruises. In 2005, Millot and Taupier-Letage have used SST satellite imagery to argue for a simpler pattern similar to the one proposed almost a century ago. During the last decade, renewed in-situ multi-platforms investigations under the framework of CYBO, CYCLOPS, NEMED, GROOM, HaiSec and PERSEUS projects, as well the development of the operational ocean forecasts and hindcasts in the framework of the MFS, ECOOP, MERSEA and MyOcean projects, have made possible to obtain an improved, higher spatial and temporal resolution picture of the circulation in the area. After some years of scientific disputes on the circulation pattern of the region, the new in-situ data sets and the operational numerical simulations confirm the relevant POEM results. The existing POM-based Cyprus Coastal Ocean Forecasting System (CYCOFOS), downscaling the MyOcean MFS, has been providing operational forecasts in the Eastern Mediterranean Levantine Basin region since early 2002. Recently, Radhakrishnan et al. (2012) parallelized the CYCOFOS hydrodynamic flow model using MPI to improve the accuracy of predictions while reducing the computational time. The parallel flow model is capable of modeling the Eastern Mediterranean Levantine Basin flow at a resolution of 500 m. The model was run in hindcast mode during which the innovations were computed using the historical data collected using gliders and cruises. Then, DD-OceanVar (D'Amore et al., 2013), a data assimilation tool based on 3DVAR developed by CMCC was used to compute the temperature and salinity field corrections. Numerical modeling results after the
NASA Astrophysics Data System (ADS)
Ings, Steven; Albertz, Markus
2014-05-01
Deformation of salt and sediments owing to the flow of weak evaporites is a common phenomenon in sedimentary basins worldwide, and the resulting structures and thermal regimes have a significant impact on hydrocarbon exploration. Evaporite sequences ('salt') of significant thickness (e.g., >1km) are typically deposited in many cycles of seawater inundation and evaporation in restricted basins resulting in layered autochthonous evaporite packages. However, analogue and numerical models of salt tectonics typically treat salt as a homogeneous viscous material, often with properties of halite, the weakest evaporite. In this study, we present results of two-dimensional plane-strain numerical experiments designed to illustrate the effects of variable evaporite viscosity and embedded frictional-plastic ('brittle') sediment layers on the style of salt flow and associated deformation of the sedimentary overburden. Evaporite viscosity is a first-order control on salt flow rate and the style of overburden deformation. Near-complete evacuation of low-viscosity salt occurs beneath expulsion basins, whereas significant salt is trapped when viscosity is high. Embedded frictional-plastic sediment layers (with finite yield strength) partition salt flow and develop transient contractional structures (folds, thrust faults, and folded faults) in a seaward salt-squeeze flow regime. Multiple internal sediment layers reduce the overall seaward salt flow during sediment aggradation, leaving more salt behind to be re-mobilized during subsequent progradation. This produces more seaward extensive allochthonous salt sheets. If there is a density difference between the embedded layers and the surrounding salt, then the embedded layers 'fractionate' during deformation and either float to the surface or sink to the bottom (depending on density), creating a thick zone of pure halite. Such a process of 'buoyancy fractionation' may partially explain the apparent paradox of layered salt in
Numerical analysis of slender vortex motion
Zhou, H.
1996-02-01
Several numerical methods for slender vortex motion (the local induction equation, the Klein-Majda equation, and the Klein-Knio equation) are compared on the specific example of sideband instability of Kelvin waves on a vortex. Numerical experiments on this model problem indicate that all these methods yield qualitatively similar behavior, and this behavior is different from the behavior of a non-slender vortex with variable cross-section. It is found that the boundaries between stable, recurrent, and chaotic regimes in the parameter space of the model problem depend on the method used. The boundaries of these domains in the parameter space for the Klein-Majda equation and for the Klein-Knio equation are closely related to the core size. When the core size is large enough, the Klein-Majda equation always exhibits stable solutions for our model problem. Various conclusions are drawn; in particular, the behavior of turbulent vortices cannot be captured by these local approximations, and probably cannot be captured by any slender vortex model with constant vortex cross-section. Speculations about the differences between classical and superfluid hydrodynamics are also offered.
Procedures for numerical analysis of circadian rhythms
REFINETTI, ROBERTO; LISSEN, GERMAINE CORNÉ; HALBERG, FRANZ
2010-01-01
This article reviews various procedures used in the analysis of circadian rhythms at the populational, organismal, cellular and molecular levels. The procedures range from visual inspection of time plots and actograms to several mathematical methods of time series analysis. Computational steps are described in some detail, and additional bibliographic resources and computer programs are listed. PMID:23710111
Carbonate aquifer of the Central Roswell Basin: recharge estimation by numerical modeling
Rehfeldt, K.R.; Gross, G.W.
1982-02-01
The flow of ground water in the Roswell, New Mexico, Artesian Basin, has been studied since the early 1900s and varied ideas have been proposed to explain different aspects of the ground water flow system. The purpose of the present study was to delineate the spatial distribution and source, or sources, of recharge to the carbonate aquifer of the central Roswell Basin. A computer model was used to simulate ground water flow in the carbonate aquifer, beneath and west of Roswell and in the Glorieta Sandstone and Yeso Formation west of the carbonate aquifer.
Numerical Analysis of Magnetic Sail Spacecraft
Sasaki, Daisuke; Yamakawa, Hiroshi; Usui, Hideyuki; Funaki, Ikkoh; Kojima, Hirotsugu
2008-12-31
To capture the kinetic energy of the solar wind by creating a large magnetosphere around the spacecraft, magneto-plasma sail injects a plasma jet into a strong magnetic field produced by an electromagnet onboard the spacecraft. The aim of this paper is to investigate the effect of the IMF (interplanetary magnetic field) on the magnetosphere of magneto-plasma sail. First, using an axi-symmetric two-dimensional MHD code, we numerically confirm the magnetic field inflation, and the formation of a magnetosphere by the interaction between the solar wind and the magnetic field. The expansion of an artificial magnetosphere by the plasma injection is then simulated, and we show that the magnetosphere is formed by the interaction between the solar wind and the magnetic field expanded by the plasma jet from the spacecraft. This simulation indicates the size of the artificial magnetosphere becomes smaller when applying the IMF.
Research in applied mathematics, numerical analysis, and computer science
NASA Technical Reports Server (NTRS)
1984-01-01
Research conducted at the Institute for Computer Applications in Science and Engineering (ICASE) in applied mathematics, numerical analysis, and computer science is summarized and abstracts of published reports are presented. The major categories of the ICASE research program are: (1) numerical methods, with particular emphasis on the development and analysis of basic numerical algorithms; (2) control and parameter identification; (3) computational problems in engineering and the physical sciences, particularly fluid dynamics, acoustics, and structural analysis; and (4) computer systems and software, especially vector and parallel computers.
NASA Astrophysics Data System (ADS)
Sehrt, Manuel; Glasmacher, Ulrich A.
2014-05-01
The Tarfaya Basin is the northern part of the Tarfaya-Laâyoune-Dakhla Basin that extends over 1000 km along the western Saharan margin from the Mauritanian border to the Canary Islands in the north. The basin is bounded by the Mauritanide thrust belt and Precambrian Reguibat Arch in the SE-E and the Palaeozoic fold belt of the Anti-Atlas in the NE. A large amount of Mesozoic terrigenous sedimentary rocks are deposited in most of the basins along the continental margin of Morocco indicating a major episode of erosion occurred during the rift and early post-rift period in the Central Atlantic. In the Tarfaya-Laâyoune-Dakhla Basin, the Mesozoic to Cenozoic sedimentary cover reaches a thickness of up to 12 km. The presence of high surface elevations in the Anti-Atlas mountain belt (2700 m) indicates a potential source area for the surrounding basins, i.e. the Tarfaya Basin. The present study was focused on the thermal and inversion history of the Tarfaya Basin, the provenance of the Meso-Cenozoic sedimentary rocks of the basin and additionally on the thermal and exhumation history of the Western Anti-Atlas. In order to characterize the t-T history, apatite and zircon fission-track dating, apatite and zircon (U-Th-Sm)/He dating and furthermore 2-D modelling with 'HeFTy' software has been carried out at Precambrian rocks of the Western Anti-Atlas and Cretaceous to Neogene sedimentary rocks from the Tarfaya Basin. Thermochronological data and t-T path modelling indicate an inversion of the onshore Tarfaya Basin in the Palaeogene. The provenance analysis suggests an almost continuous sediment transport from the Anti-Atlas to the Tarfaya Basin and a simultaneous sediment input from the Reguibat Shield.
Dongarra, J. |; Rosener, B.
1991-12-01
This report describes a facility called NA-NET created to allow numerical analysts (na) an easy method of communicating with one another. The main advantage of the NA-NET is uniformity of addressing. All mail is addressed to the Internet host ``na-net.ornl.gov`` at Oak Ridge National Laboratory. Hence, members of the NA-NET do not need to remember complicated addresses or even where a member is currently located. As long as moving members change their e-mail address in the NA-NET everything works smoothly. The NA-NET system is currently located at Oak Ridge National Laboratory. It is running on the same machine that serves netlib. Netlib is a separate facility that distributes mathematical software via electronic mail. For more information on netlib consult, or send the one-line message ``send index`` to netlib{at}ornl.gov. The following report describes the current NA-NET system from both a user`s perspective and from an implementation perspective. Currently, there are over 2100 members in the NA-NET. An average of 110 mail messages pass through this facility daily.
Dongarra, J. . Dept. of Computer Science Oak Ridge National Lab., TN ); Rosener, B. . Dept. of Computer Science)
1991-12-01
This report describes a facility called NA-NET created to allow numerical analysts (na) an easy method of communicating with one another. The main advantage of the NA-NET is uniformity of addressing. All mail is addressed to the Internet host na-net.ornl.gov'' at Oak Ridge National Laboratory. Hence, members of the NA-NET do not need to remember complicated addresses or even where a member is currently located. As long as moving members change their e-mail address in the NA-NET everything works smoothly. The NA-NET system is currently located at Oak Ridge National Laboratory. It is running on the same machine that serves netlib. Netlib is a separate facility that distributes mathematical software via electronic mail. For more information on netlib consult, or send the one-line message send index'' to netlib{at}ornl.gov. The following report describes the current NA-NET system from both a user's perspective and from an implementation perspective. Currently, there are over 2100 members in the NA-NET. An average of 110 mail messages pass through this facility daily.
NASA Astrophysics Data System (ADS)
Sophocleous, M. A.; Koelliker, J. K.; Govindaraju, R. S.; Birdie, T.; Ramireddygari, S. R.; Perkins, S. P.
1999-01-01
The objective of this article is to develop and implement a comprehensive computer model that is capable of simulating the surface-water, ground-water, and stream-aquifer interactions on a continuous basis for the Rattlesnake Creek basin in south-central Kansas. The model is to be used as a tool for evaluating long-term water-management strategies. The agriculturally-based watershed model SWAT and the ground-water model MODFLOW with stream-aquifer interaction routines, suitably modified, were linked into a comprehensive basin model known as SWATMOD. The hydrologic response unit concept was implemented to overcome the quasi-lumped nature of SWAT and represent the heterogeneity within each subbasin of the basin model. A graphical user-interface and a decision support system were also developed to evaluate scenarios involving manipulation of water rights and agricultural land uses on stream-aquifer system response. An extensive sensitivity analysis on model parameters was conducted, and model limitations and parameter uncertainties were emphasized. A combination of trial-and-error and inverse modeling techniques were employed to calibrate the model against multiple calibration targets of measured ground-water levels, streamflows, and reported irrigation amounts. The split-sample technique was employed for corroborating the calibrated model. The model was run for a 40 y historical simulation period, and a 40 y prediction period. A number of hypothetical management scenarios involving reductions and variations in withdrawal rates and patterns were simulated. The SWATMOD model was developed as a hydrologically rational low-flow model for analyzing, in a user-friendly manner, the conditions in the basin when there is a shortage of water.
Sophocleous, M.A.; Koelliker, J.K.; Govindaraju, R.S.; Birdie, T.; Ramireddygari, S.R.; Perkins, S.P.
1999-01-01
The objective of this article is to develop and implement a comprehensive computer model that is capable of simulating the surface-water, ground-water, and stream-aquifer interactions on a continuous basis for the Rattlesnake Creek basin in south-central Kansas. The model is to be used as a tool for evaluating long-term water-management strategies. The agriculturally-based watershed model SWAT and the ground-water model MODFLOW with stream-aquifer interaction routines, suitably modified, were linked into a comprehensive basin model known as SWATMOD. The hydrologic response unit concept was implemented to overcome the quasi-lumped nature of SWAT and represent the heterogeneity within each subbasin of the basin model. A graphical user-interface and a decision support system were also developed to evaluate scenarios involving manipulation of water fights and agricultural land uses on stream-aquifer system response. An extensive sensitivity analysis on model parameters was conducted, and model limitations and parameter uncertainties were emphasized. A combination of trial-and-error and inverse modeling techniques were employed to calibrate the model against multiple calibration targets of measured ground-water levels, streamflows, and reported irrigation amounts. The split-sample technique was employed for corroborating the calibrated model. The model was run for a 40 y historical simulation period, and a 40 y prediction period. A number of hypothetical management scenarios involving reductions and variations in withdrawal rates and patterns were simulated. The SWATMOD model was developed as a hydrologically rational low-flow model for analyzing, in a user-friendly manner, the conditions in the basin when there is a shortage of water.
NASA Astrophysics Data System (ADS)
Zanini, A.; Tanda, M.
2007-12-01
The groundwater in Italy plays an important role as drinking water; in fact it covers about the 30% of the national demand (70% in Northern Italy). The mineral water distribution in Italy is an important business with an increasing demand from abroad countries. The mineral water Companies have a great interest in order to increase the water extraction, but for the delicate and complex geology of the subsoil, where such very high quality waters are contained, a particular attention must be paid in order to avoid an excessive lowering of the groundwater reservoirs or great changes in the groundwater flow directions. A big water Company asked our University to set up a numerical model of the groundwater basin, in order to obtain a useful tool which allows to evaluate the strength of the aquifer and to design new extraction wells. The study area is located along Appennini Mountains and it covers a surface of about 18 km2; the topography ranges from 200 to 600 m a.s.l.. In ancient times only a spring with naturally sparkling water was known in the area, but at present the mineral water is extracted from deep pumping wells. The area is characterized by a very complex geology: the subsoil structure is described by a sequence of layers of silt-clay, marl-clay, travertine and alluvial deposit. Different groundwater layers are present and the one with best quality flows in the travertine layer; the natural flow rate seems to be not subjected to seasonal variations. The water age analysis revealed a very old water which means that the mineral aquifers are not directly connected with the meteoric recharge. The Geologists of the Company suggest that the water supply of the mineral aquifers comes from a carbonated unit located in the deep layers of the mountains bordering the spring area. The valley is crossed by a river that does not present connections to the mineral aquifers. Inside the area there are about 30 pumping wells that extract water at different depths. We built a 3
An analysis of the carbon balance of the Arctic Basin
Mcguire, David; Hayes, Daniel J; Kicklighter, David W.; Manizza, Manfredi; Zhuang, Qianlai; Chen, Min; Follows, Michael J; Gurney, Kevin; Mcclelland, James W; Melillo, Jerry; Peterson, Bruce; Prinn, Ronald
2010-01-01
This study used several model-based tools to analyse the dynamics of the Arctic Basin between 1997 and 2006 as a linked system of land-ocean-atmosphere C exchange. The analysis estimates that terrestrial areas of the Arctic Basin lost 62.9 Tg C yr 1 and that the Arctic Ocean gained 94.1 Tg C yr 1. Arctic lands and oceans were a net CO2 sink of 108.9 Tg C yr 1, which is within the range of uncertainty in estimates from atmospheric inversions. Although both lands and oceans of the Arctic were estimated to be CO2 sinks, the land sink diminished in strength because of increased fire disturbance compared to previous decades, while the ocean sink increased in strength because of increased biological pump activity associated with reduced sea ice cover. Terrestrial areas of the Arctic were a net source of 41.5 Tg CH4 yr 1 that increased by 0.6 Tg CH4 yr 1 during the decade of analysis, a magnitude that is comparable with an atmospheric inversion of CH4. Because the radiative forcing of the estimated CH4 emissions is much greater than the CO2 sink, the analysis suggests that the Arctic Basin is a substantial net source of green house gas forcing to the climate system.
Numerical analysis and design of upwind sails
NASA Astrophysics Data System (ADS)
Shankaran, Sriram
The use of computational techniques that solve the Euler or the Navier-Stokes equations are increasingly being used by competing syndicates in races like the Americas Cup. For sail configurations, this desire stems from a need to understand the influence of the mast on the boundary layer and pressure distribution on the main sail, the effect of camber and planform variations of the sails on the driving and heeling force produced by them and the interaction of the boundary layer profile of the air over the surface of the water and the gap between the boom and the deck on the performance of the sail. Traditionally, experimental methods along with potential flow solvers have been widely used to quantify these effects. While these approaches are invaluable either for validation purposes or during the early stages of design, the potential advantages of high fidelity computational methods makes them attractive candidates during the later stages of the design process. The aim of this study is to develop and validate numerical methods that solve the inviscid field equations (Euler) to simulate and design upwind sails. The three dimensional compressible Euler equations are modified using the idea of artificial compressibility and discretized on unstructured tetrahedral grids to provide estimates of lift and drag for upwind sail configurations. Convergence acceleration techniques like multigrid and residual averaging are used along with parallel computing platforms to enable these simulations to be performed in a few minutes. To account for the elastic nature of the sail cloth, this flow solver was coupled to NASTRAN to provide estimates of the deflections caused by the pressure loading. The results of this aeroclastic simulation, showed that the major effect of the sail elasticity; was in altering the pressure distribution around the leading edge of the head and the main sail. Adjoint based design methods were developed next and were used to induce changes to the camber
Dinicola, Richard S.
2001-01-01
The validity of a previously determined numerical modeling method was assessed. Numerical models for 11 drainage basins were constructed with the Hydrologic Simulation Program-FORTRAN (HSPF) with parameter values that were generalized for the physiographic region. Large and recurrent simulation errors were initially identified, but three systematic modifications of the models corrected those errors for 10 out of the 11 basins. The validity of the numerical modeling method for simulating rainfall-runoff relations in the study area, as modified during this investigation, was not rejected, but observed streamflow data were needed to apply the method.
Numerical bifurcation analysis of immunological models with time delays
NASA Astrophysics Data System (ADS)
Luzyanina, Tatyana; Roose, Dirk; Bocharov, Gennady
2005-12-01
In recent years, a large number of mathematical models that are described by delay differential equations (DDEs) have appeared in the life sciences. To analyze the models' dynamics, numerical methods are necessary, since analytical studies can only give limited results. In turn, the availability of efficient numerical methods and software packages encourages the use of time delays in mathematical modelling, which may lead to more realistic models. We outline recently developed numerical methods for bifurcation analysis of DDEs and illustrate the use of these methods in the analysis of a mathematical model of human hepatitis B virus infection.
Numerical Uncertainty Quantification for Radiation Analysis Tools
NASA Technical Reports Server (NTRS)
Anderson, Brooke; Blattnig, Steve; Clowdsley, Martha
2007-01-01
Recently a new emphasis has been placed on engineering applications of space radiation analyses and thus a systematic effort of Verification, Validation and Uncertainty Quantification (VV&UQ) of the tools commonly used for radiation analysis for vehicle design and mission planning has begun. There are two sources of uncertainty in geometric discretization addressed in this paper that need to be quantified in order to understand the total uncertainty in estimating space radiation exposures. One source of uncertainty is in ray tracing, as the number of rays increase the associated uncertainty decreases, but the computational expense increases. Thus, a cost benefit analysis optimizing computational time versus uncertainty is needed and is addressed in this paper. The second source of uncertainty results from the interpolation over the dose vs. depth curves that is needed to determine the radiation exposure. The question, then, is what is the number of thicknesses that is needed to get an accurate result. So convergence testing is performed to quantify the uncertainty associated with interpolating over different shield thickness spatial grids.
A numerical comparison of sensitivity analysis techniques
Hamby, D.M.
1993-12-31
Engineering and scientific phenomena are often studied with the aid of mathematical models designed to simulate complex physical processes. In the nuclear industry, modeling the movement and consequence of radioactive pollutants is extremely important for environmental protection and facility control. One of the steps in model development is the determination of the parameters most influential on model results. A {open_quotes}sensitivity analysis{close_quotes} of these parameters is not only critical to model validation but also serves to guide future research. A previous manuscript (Hamby) detailed many of the available methods for conducting sensitivity analyses. The current paper is a comparative assessment of several methods for estimating relative parameter sensitivity. Method practicality is based on calculational ease and usefulness of the results. It is the intent of this report to demonstrate calculational rigor and to compare parameter sensitivity rankings resulting from various sensitivity analysis techniques. An atmospheric tritium dosimetry model (Hamby) is used here as an example, but the techniques described can be applied to many different modeling problems. Other investigators (Rose; Dalrymple and Broyd) present comparisons of sensitivity analyses methodologies, but none as comprehensive as the current work.
Numerical analysis on pump turbine runaway points
NASA Astrophysics Data System (ADS)
Guo, L.; Liu, J. T.; Wang, L. Q.; Jiao, L.; Li, Z. F.
2012-11-01
To research the character of pump turbine runaway points with different guide vane opening, a hydraulic model was established based on a pumped storage power station. The RNG k-ε model and SMPLEC algorithms was used to simulate the internal flow fields. The result of the simulation was compared with the test data and good correspondence was got between experimental data and CFD result. Based on this model, internal flow analysis was carried out. The result show that when the pump turbine ran at the runway speed, lots of vortexes appeared in the flow passage of the runner. These vortexes could always be observed even if the guide vane opening changes. That is an important way of energy loss in the runaway condition. Pressure on two sides of the runner blades were almost the same. So the runner power is very low. High speed induced large centrifugal force and the small guide vane opening gave the water velocity a large tangential component, then an obvious water ring could be observed between the runner blades and guide vanes in small guide vane opening condition. That ring disappeared when the opening bigger than 20°. These conclusions can provide a theory basis for the analysis and simulation of the pump turbine runaway points.
Synoptic climatological analysis of persistent cold air pools over the Carpathian Basin
NASA Astrophysics Data System (ADS)
Szabóné André, Karolina; Bartholy, Judit; Pongrácz, Rita
2016-04-01
A persistent cold air pool (PCAP) is a winter-time, anticyclone-related weather event over a relatively large basin. During this time the air is colder near the surface than aloft. This inversion near the surface can last even for weeks. As the cold air cools down, relative humidity increases and fog forms. The entire life cycle of a PCAP depends on the large scale circulation pattern. PCAP usually appears when an anticyclone builds up after a cold front passed over the examined basin, and it is usually destructed by a coming strong cold front of another midlatitude cyclone. Moreover, the intensity of the anticyclone affects the intensity of the PCAP. PCAP may result in different hazards for the population: (1) Temperature inversion in the surface layers together with weak wind may lead to severe air pollution causing health problems for many people, especially, elderly and children. (2) The fog and/or smog during chilly weather conditions often results in freezing rain. Both fog and freezing rain can distract transportation and electricity supply. Unfortunately, the numerical weather prediction models have difficulties to predict PCAP formation and destruction. One of the reasons is that PCAP is not defined objectively with a simple formula, which could be easily applied to the numerical output data. However, according to some recommendations from the synoptic literature, the shallow convective potential energy (SCPE) can be used to mathematically describe PCAP. In this study, we used the ERA-Interim reanalysis datasets to examine this very specific weather event (i.e., PCAP) over the Carpathian Basin. The connection between the mean sea level pressure and some PCAP measures (e.g., SCPE, energy deficit, etc.) is evaluated. For instance, we used logistic regression to identify PCAP periods over the Carpathian Basin. Then, further statistical analysis includes the evaluation of the length and intensity of these PCAP periods.
Numerical analysis of human dental occlusal contact
NASA Astrophysics Data System (ADS)
Bastos, F. S.; Las Casas, E. B.; Godoy, G. C. D.; Meireles, A. B.
2010-06-01
The purpose of this study was to obtain real contact areas, forces, and pressures acting on human dental enamel as a function of the nominal pressure during dental occlusal contact. The described development consisted of three steps: characterization of the surface roughness by 3D contact profilometry test, finite element analysis of micro responses for each pair of main asperities in contact, and homogenization of macro responses using an assumed probability density function. The inelastic deformation of enamel was considered, adjusting the stress-strain relationship of sound enamel to that obtained from instrumented indentation tests conducted with spherical tip. A mechanical part of the static friction coefficient was estimated as the ratio between tangential and normal components of the overall resistive force, resulting in μd = 0.057. Less than 1% of contact pairs reached the yield stress of enamel, indicating that the occlusal contact is essentially elastic. The micro-models indicated an average hardness of 6.25GPa, and the homogenized result for macroscopic interface was around 9GPa. Further refinements of the methodology and verification using experimental data can provide a better understanding of processes related to contact, friction and wear of human tooth enamel.
Combustion irreversibilities: Numerical simulation and analysis
NASA Astrophysics Data System (ADS)
Silva, Valter; Rouboa, Abel
2012-08-01
An exergy analysis was performed considering the combustion of methane and agro-industrial residues produced in Portugal (forest residues and vines pruning). Regarding that the irreversibilities of a thermodynamic process are path dependent, the combustion process was considering as resulting from different hypothetical paths each one characterized by four main sub-processes: reactant mixing, fuel oxidation, internal thermal energy exchange (heat transfer), and product mixing. The exergetic efficiency was computed using a zero dimensional model developed by using a Visual Basic home code. It was concluded that the exergy losses were mainly due to the internal thermal energy exchange sub-process. The exergy losses from this sub-process are higher when the reactants are preheated up to the ignition temperature without previous fuel oxidation. On the other hand, the global exergy destruction can be minored increasing the pressure, the reactants temperature and the oxygen content on the oxidant stream. This methodology allows the identification of the phenomena and processes that have larger exergy losses, the understanding of why these losses occur and how the exergy changes with the parameters associated to each system which is crucial to implement the syngas combustion from biomass products as a competitive technology.
NASCRIN - NUMERICAL ANALYSIS OF SCRAMJET INLET
NASA Technical Reports Server (NTRS)
Kumar, A.
1994-01-01
The NASCRIN program was developed for analyzing two-dimensional flow fields in supersonic combustion ramjet (scramjet) inlets. NASCRIN solves the two-dimensional Euler or Navier-Stokes equations in conservative form by an unsplit, explicit, two-step finite-difference method. A more recent explicit-implicit, two-step scheme has also been incorporated in the code for viscous flow analysis. An algebraic, two-layer eddy-viscosity model is used for the turbulent flow calculations. NASCRIN can analyze both inviscid and viscous flows with no struts, one strut, or multiple struts embedded in the flow field. NASCRIN can be used in a quasi-three-dimensional sense for some scramjet inlets under certain simplifying assumptions. Although developed for supersonic internal flow, NASCRIN may be adapted to a variety of other flow problems. In particular, it should be readily adaptable to subsonic inflow with supersonic outflow, supersonic inflow with subsonic outflow, or fully subsonic flow. The NASCRIN program is available for batch execution on the CDC CYBER 203. The vectorized FORTRAN version was developed in 1983. NASCRIN has a central memory requirement of approximately 300K words for a grid size of about 3,000 points.
Analysis of water from K west basin canisters (second campaign)
Trimble, D.J., Fluor Daniel Hanford
1997-03-06
Gas and liquid samples have been obtained from a selection of the approximately 3,820 spent fuel storage canisters in the K West Basin. The samples were taken to characterize the contents of the gas and water in the canisters. The data will provide source term information for two subprojects of the Spent Nuclear Fuel Project (SNFP) (Fulton 1994): the K Basins Integrated Water Treatment System subproject (Ball 1996) and the K Basins Fuel Retrieval System subproject (Waymire 1996). The barrels of ten canisters were sampled in 1995, and 50 canisters were sampled in a second campaign in 1996. The analysis results for the gas and liquid samples of the first campaign have been reported (Trimble 1995a; Trimble 1995b; Trimble 1996a; Trimble 1996b). An analysis of cesium-137 (137CS ) data from the second campaign samples was reported (Trimble and Welsh 1997), and the gas sample results are documented in Trimble 1997. This report documents the results of all analytes of liquid samples from the second campaign.
Ernest A. Mancini
2004-02-05
The principal research effort for Year 1 of the project is data compilation and the determination of the tectonic and depositional histories of the North Louisiana Salt Basin. In the first three (3) to six (6) months of Year 1, the research focus is on data compilation and the remainder of the year the emphasis is on the tectonic and depositional histories of the basin. No major problems have been encountered to date, and the project is on schedule. The principal objectives of the project are to develop through basin analysis and modeling the concept that petroleum systems acting in a basin can be identified through basin modeling and to demonstrate that the information and analysis resulting from characterizing and modeling of these petroleum systems in the North Louisiana Salt Basin and the Mississippi Interior Salt Basin can be used in providing a more reliable and advanced approach for targeting stratigraphic traps and specific reservoir facies within a geologic system and in providing a refined assessment of undiscovered and underdeveloped reservoirs and associated oil and gas resources.
Carlson, Carl S.; Mondazzi, Remo A.; Bjerklie, David M.; Brown, Craig J.
2010-01-01
A study of the groundwater and stream-aquifer interaction in the Pootatuck River Basin, Newtown, Connecticut, was conducted to analyze the effect of production wells on the groundwater levels and streamflow in the Pootatuck River as part of a cooperative program between the U.S. Geological Survey and Newtown, Connecticut. This study will help address concerns about the increasing competition for water for human uses and protection of aquatic habitat. The groundwater-flow model developed in the study was designed for use as a tool to assist planners in assessing the effects of potential future development, which will change the amount and distribution of recharge available to the groundwater system. Several different techniques were used to investigate the interconnection between the stream and the aquifer. Temperature, groundwater levels, stream stage, and stable-isotope data collected during aquifer tests at the principal production wells in the Pootatuck River Basin, as well as groundwater-flow simulations of the system, indicate that more than half of the water pumped from the wells comes from the Pootatuck River. This finding potentially has a large effect on approaches for protecting the water quality of the pumped water. Increases in the amount of impervious surface from future development will reduce and redistribute recharge to the groundwater system. The simulation of future development scenarios showed a decrease in the simulated base flow in the main stem of the Pootatuck River and in all of the 26 simulated subbasins, with some of the subbasins showing a decrease of more than 20 percent when new development had 85 percent impervious area. The groundwater-flow model and particle tracking were used to determine areas that contribute recharge to the five production wells available for use in the Pootatuck River Basin. These areas included narrow portions of the aquifer that extended beyond the immediate upgradient areas, probably because of deeper
NASA Astrophysics Data System (ADS)
Yamato, Philippe; Castelltort, Sébastien; Willett, Sean
2010-05-01
The last two decades have been marked by a large amount of studies on the relative influences of climate and tectonics on landscape evolution. Coevally, considerable advances have been achieved in numerical modelling of landscape evolution. These have been particularly useful in testing hypotheses and scenarios of the potential controls and feedbacks between climate, tectonics and landscape evolution. However, our current knowledge of the physical processes of erosion in nature remains incomplete. Indeed, although the predictions of landscape evolution models are often insightful, they are also sometimes overlooked due to their lack of physical basis. In parallel with current field and experimental investigations on erosion processes, one way to tackle this problem is to compare simulated and natural landscapes. Then, this allows us to know how can one assess whether a simulated landscape is realistic in a long-standing problem in geomorphology. The scaling between stream length and upstream drainage area, a relation known as Hack's law (Hack, 1957) provides a constrain on the geometry of natural landscapes. It is however notoriously difficult to use this law to assess the goodness of a landscape evolution model since it must be regarded over a logarithmic range of scales (stream orders), which is usually not possible in landscape evolution models because of their resolution. The convergence angle, a measure of a basin's elongation (Castelltort et al., 2009) is a similar metrics of drainage basin shape. It is controlled by the slope and roughness of the undissected surface on which a new basin develops. This relation arises from analytical predictions of water flow over simple topography and is supported by data on median to large-scale natural networks. In the present study we investigate the influence of slope and surface roughness on the shape of river basins using the CASCADE code (Braun and Sambridge, 1997). Results show that the rules used to route water in
Regional Slip Tendency Analysis of the Great Basin Region
Faulds, James E.
2013-09-30
are shown on Figure 3. For faults within the Great Basin proper, we applied a normal faulting stress regime, where the vertical stress (sv) is larger than the maximum horizontal stress (shmax), which is larger than the minimum horizontal stress (sv>shmax>shmin). Based on visual inspection of the limited stress magnitude data in the Great Basin, we used magnitudes such that shmin/shmax = .527 and shmin/sv= .46. These values are consistent with stress magnitude data at both Dixie Valley (Hickman et al., 2000) and Yucca Mountain (Stock et al., 1985). For faults within the Walker Lane/Eastern California Shear Zone, we applied a strike‐slip faulting stress, where shmax > sv > shmin. Upon visual inspection of limited stress magnitude data from the Walker Lane and Eastern California Shear zone, we chose values such that SHmin/SHmax = .46 and Shmin/Sv= .527 representative of the region. Results: The results of our slip and dilation tendency analysis are shown in Figures 4 (dilation tendency), 5 (slip tendency) and 6 (slip tendency + dilation tendency). Shmin varies from northwest to east‐west trending throughout much of the Great Basin. As such, north‐ to northeast‐striking faults have the highest tendency to slip and to dilate, depending on the local trend of shmin. These results provide a first order filter on faults and fault systems in the Great Basin, affording focusing of local‐scale exploration efforts for blind or hidden geothermal resources.
NASA Astrophysics Data System (ADS)
Sonibare, W. A.; Scheck-Wenderoth, M.; Sippel, J.; Mikeš, D.
2012-04-01
+ (Interactive Gravity and Magnetic Assistant System; Götze et al., 2010 and Schmidt et al., 2011). The ensuing model will be applied to predict the present-day deep crustal configuration and thermal field characteristics of the basin. Thereafter, 3D volumetric backstripping analysis will be performed to predict basin subsidence mechanisms (i.e. tectonic, thermal and sediment load) through time as well as to estimate paleo-water depths for paleogeographic reconstruction. The information gathered from crust-scale basin dynamics will be subsequently used at the petroleum system modelling stage to holistically assess the hydrocarbon potential of the basin in terms of source rock maturity and hydrocarbon generation, migration, timing and accumulation.
A hydrologic analysis for the infiltration basins planned on Jeju Island, Korea
NASA Astrophysics Data System (ADS)
Lee, S.; Kang, T.; Lee, J.; Kang, S.
2010-12-01
Urban development is a cause of expansion of impervious area. It reduces infiltration of rain water and may increase runoff volume from storms. Infiltration basins can be a method to receive storm water and to let the water move into the soil. The contents of the study include a hydrologic analysis on a site and an evaluation of the capacity of infiltration basins planned on the site. Most region of Jeju Island, Korea is highly pervious. Three infiltration basins were designed on the area of the Jeju English Education City. To evaluate adequacy of the capacities of the infiltration basins, infiltration rates were measured and storm water runoff was simulated. Infiltration rates on the surface of the reserved land for infiltration basins were measured by a standard double ring infiltrometer or a small infiltrometer. A FORTRAN version of SWMM was modified to incorporate the infiltration basin and the basic equations of the infiltration basin are same as those of the infiltration trench used in MIDUSS. The code modified was used to simulate storm runoff from watersheds, infiltration from the infiltration basins, and reservoir routing of the infiltration basins. The saturated hydraulic conductivities on the reserved sites were measured by 0.0068, 0.0038, and 0.00017 cm/sec. The return period of the design rainfall is fifty years. The following results were obtained from a hydrologic analysis on the watersheds and the infiltration basins to be built. The two infiltration basins with higher infiltration rates have adequate capacities to infiltrate the total water inflow to the basins. Some water, however releases from the other infiltration basin and the capacity of the basin is not sufficient to infiltrate the total runoff after the land use change. A channel is needed in which the water released from the less pervious basin flows. The hydrologic analysis method of the study can be used for capacity evaluation of future infiltration basins on highly pervious areas in
NASA Astrophysics Data System (ADS)
Cruciani, Francesco; Manconi, Andrea; Rinaldo Barchi, Massimiliano
2014-05-01
Gravity-driven deformation processes at continental passive margins occur at different scales, from small-scale turbidity currents and sediment slides, to large-scale mass transport complexes (MTCs), to the giant-scale deep water fold and thrust belts (DW-FTBs), which affect most or the entire sedimentary sequence. This kind of giant structures, quite widespread in passive margins, may be active for tens of millions of years. In this context, the Brazilian Atlantic margin hosts several well-known DW-FTBs detached on both shale and salt décollement. Despite of their relevant scientific and economic importance, the mechanical processes driving the onset and evolution of these giant-scale structures are still poorly investigated. In this work, we focus on the shale décollement DW-FTB of the Barreirinhas Basin, where the continental slope has been affected by multi-phase gravitational processes since the Late Cretaceous. This DW-FTB consists of a linked fault system of listric normal faults updip and thrust faults downdip, detached over a common concave upward décollement surface. From the onshore extensional to the offshore compressional domain the DW-FTB is about 50 km wide and involve a sedimentary sequence up to 5 km thick. Shortening within the compressional domain is accommodated almost entirely from a single thrust ramp with a large related anticline fold. Previous studies have shown that the main activity phases of the gravitational processes are closely linked to significant increases in the sediment supply within the basin. Indeed, the highest deformation rate, accounting for about 80% of the net strain, occurred in the Upper Miocene following a drainage rearrangement which led to the birth of the modern Amazon River drainage system. The Barreirinhas Basin DW-FTB entails a rather simple geometrical structure, which can be well schematized, therefore is particularly suitable for numerical simulations aimed to study and understand the dynamics of DW-FTB at
A general numerical model for wave rotor analysis
NASA Technical Reports Server (NTRS)
Paxson, Daniel W.
1992-01-01
Wave rotors represent one of the promising technologies for achieving very high core temperatures and pressures in future gas turbine engines. Their operation depends upon unsteady gas dynamics and as such, their analysis is quite difficult. This report describes a numerical model which has been developed to perform such an analysis. Following a brief introduction, a summary of the wave rotor concept is given. The governing equations are then presented, along with a summary of the assumptions used to obtain them. Next, the numerical integration technique is described. This is an explicit finite volume technique based on the method of Roe. The discussion then focuses on the implementation of appropriate boundary conditions. Following this, some results are presented which first compare the numerical approximation to the governing differential equations and then compare the overall model to an actual wave rotor experiment. Finally, some concluding remarks are presented concerning the limitations of the simplifying assumptions and areas where the model may be improved.
NASA Astrophysics Data System (ADS)
Pfunt, Helena; Houben, Georg; Himmelsbach, Thomas
2016-04-01
Gas production from shale formations by hydraulic fracturing has raised concerns about the effects on the quality of fresh groundwater. The migration of injected fracking fluids towards the surface was investigated in the North German Basin, based on the known standard lithology. This included cases with natural preferential pathways such as permeable fault zones and fracture networks. Conservative assumptions were applied in the simulation of flow and mass transport triggered by a high pressure boundary of up to 50 MPa excess pressure. The results show no significant fluid migration for a case with undisturbed cap rocks and a maximum of 41 m vertical transport within a permeable fault zone during the pressurization. Open fractures, if present, strongly control the flow field and migration; here vertical transport of fracking fluids reaches up to 200 m during hydraulic fracturing simulation. Long-term transport of the injected water was simulated for 300 years. The fracking fluid rises vertically within the fault zone up to 485 m due to buoyancy. Progressively, it is transported horizontally into sandstone layers, following the natural groundwater flow direction. In the long-term, the injected fluids are diluted to minor concentrations. Despite the presence of permeable pathways, the injected fracking fluids in the reported model did not reach near-surface aquifers, either during the hydraulic fracturing or in the long term. Therefore, the probability of impacts on shallow groundwater by the rise of fracking fluids from a deep shale-gas formation through the geological underground to the surface is small.
Investigating Convergence Patterns for Numerical Methods Using Data Analysis
ERIC Educational Resources Information Center
Gordon, Sheldon P.
2013-01-01
The article investigates the patterns that arise in the convergence of numerical methods, particularly those in the errors involved in successive iterations, using data analysis and curve fitting methods. In particular, the results obtained are used to convey a deeper level of understanding of the concepts of linear, quadratic, and cubic…
Scilab and Maxima Environment: Towards Free Software in Numerical Analysis
ERIC Educational Resources Information Center
Mora, Angel; Galan, Jose Luis; Aguilera, Gabriel; Fernandez, Alvaro; Merida, Enrique; Rodriguez, Pedro
2010-01-01
In this work we will present the ScilabUMA environment we have developed as an alternative to Matlab. This environment connects Scilab (for numerical analysis) and Maxima (for symbolic computations). Furthermore, the developed interface is, in our opinion at least, as powerful as the interface of Matlab. (Contains 3 figures.)
Mancini, Ernest A.
2003-02-06
The project objectives are improving access to information for the Mississippi Interior Salt Basin by inventorying data files and records of the major information repositories in the region, making these inventories easily accessible in electronic format, increasing the amount of information available on domestic sedimentary basins through a comprehensive analysis of the Mississippi Interior Salt Basin, and enhancing the understanding of the petroleum systems operating in the Mississippi Interior Salt Basin.
Tularosa Basin Play Fairway Analysis: Partial Basin and Range Heat and Zones of Critical Stress Maps
Adam Brandt
2015-11-15
Interpolated maps of heat flow, temperature gradient, and quartz geothermometers are included as TIF files. Zones of critical stress map is also included as a TIF file. The zones are given a 5km diameter buffer. The study area is only a part of the Basin and Range, but it does includes the Tularosa Basin.
Classification and analysis of candidate impact crater-hosted closed-basin lakes on Mars
NASA Astrophysics Data System (ADS)
Goudge, Timothy A.; Aureli, Kelsey L.; Head, James W.; Fassett, Caleb I.; Mustard, John F.
2015-11-01
We present a new catalog of 205 candidate closed-basin lakes contained within impact craters across the surface of Mars. These basins have an inlet valley that incises the crater rim and flows into the basin but no visible outlet valley, and are considered candidate closed-basin lakes; the presence of a valley flowing into a basin does not necessitate the formation of a standing body of water. The major geomorphic distinction within our catalog of candidate paleolakes is the length of the inlet valley(s), with two major classes - basins with long (>20 km) inlet valleys (30 basins), and basins with short (<20 km) inlet valleys (175 basins). We identify 55 basins that contain sedimentary fan deposits at the mouths of their inlet valleys, of which nine are fed by long inlet valleys and 46 are fed by short inlet valleys. Analysis of the mineralogy of these fan deposits suggests that they are primarily composed of detrital material. Additionally, we find no evidence for widespread evaporite deposit formation within our catalog of candidate closed-basin lakes, which we conclude is indicative of a general transience for any lakes that did form within these basins. Morphometric characteristics for our catalog indicate that as an upper limit, these basins represent a volume of water equivalent to a ∼1.2 m global equivalent layer (GEL) of water spread evenly across the martian surface; this is a small fraction of the modern water ice reservoir on Mars. Our catalog offers a broader context within which results from the Mars Science Laboratory Curiosity rover can be interpreted, as Gale crater is a candidate closed-basin lake contained within our catalog. Gale is also one of 12 closed-basin lakes fed by both long and short inlet valleys, and so in␣situ analyses by Curiosity can shed light on the relative importance of these two types of inlets for any lacustrine activity within the basin.
NASA Astrophysics Data System (ADS)
Dhaoui, Mohamed; Gabtni, Hakim; Jallouli, Chokri; Jleilia, Ali; Mickus, Kevin Lee; Turki, Mohamed Moncef
2014-12-01
Gravity data were analyzed to determine the structural development of the northern boundary of the Ghadames Basin in southern Tunisia. The Ghadames Basin which also occurs in eastern Algeria and northwestern Libya is one of the most prolific hydrocarbon producers in North Africa with several of the largest oil fields occurring along its northern boundary. The Ghadames Basin was formed during a series of tectonic events ranging from the Early Paleozoic to the Early Cenozoic. These tectonic events produced a basin in southern Tunisia that has a complex basement configuration which is not completely known. A residual gravity anomaly map constructed using polynomial trend surfaces, and vertical and horizontal gravity derivative maps indicate that the northern boundary contains a series of maxima and minima anomalies that trend in two prominent directions: northeast-southwest and east-west. The horizontal and vertical derivative gravity anomaly maps indicate that the width of the basement structures range between 10 and 20 km in width. Three-dimensional (3D) Euler deconvolution and 3D forward modeling constrained by well data, one seismic reflection profile and remote sensing data confirm the width of the basement structures and indicates that the depth of basin varies between 1.5 and 5 km, with deeper sections in general more numerous in the southern sections of the boundary. The gravity analysis constrained by the seismic reflection profile and well data implies that the basement topography may have been formed during the Pan African and/or late Mesozoic rifting. However, additional seismic reflection and well data are needed to confirm this conclusion. The discovery of the numerous basement structures suggests that there may exist additional hydrocarbon traps within the northern boundary of the Ghadames Basin.
Formulation of numerical procedures for dynamic analysis of spinning structures
NASA Technical Reports Server (NTRS)
Gupta, K. K.
1986-01-01
The paper presents the descriptions of recently developed numerical algorithms that prove to be useful for the solution of the free vibration problem of spinning structures. First, a generalized procedure for the computation of nodal centrifugal forces in a finite element owing to any specified spin rate is derived in detail. This is followed by a description of an improved eigenproblem solution procedure that proves to be economical for the free vibration analysis of spinning structures. Numerical results are also presented which indicate the efficacy of the currently developed procedures.
Basin analysis of tertiary strata in the Pattani Basin, Gulf of Thailand
Chonchawalit, A. ); Bustin, R.M. )
1994-07-01
The stratigraphic and structural evolution of the Pattani basin, the most prolific petroleum basin in Thailand, reflects the extensional tectonics of continental southeast Asia. East-west extension, a product of the northward collision of India with Eurasia since the early Tertiary resulted in the formation of a series of north-south-trending sedimentary basins including the Pattani basin. Subsidence and thermal histories of the basin can generally be accounted for by nonuniform lithospheric stretching. The validity of nonuniform lithospheric stretching as a mechanic for the formation of the Pattani basin is confirmed by a reasonably good agreement between modeled and observed vitrinite reflectance at various depths and locations. The amount of stretching and surface heat flow generally increases from the basin margin to the basin center. Crustal stretching factor ([beta]) ranges from 1.3 at the basin margin to 2.8 in the center. Subcrustal stretching factor ([sigma]) ranges from 1.3 at the margin to more than 3.0 in the center. The stretching of the lithosphere may have extended basement rocks as much as 45 to 90 km and may have caused the upwelling of asthenosphere, resulting in high heat flow. The sedimentary succession in the Pattani basin is divisible into synrift and postrift sequences. The synrift sequences comprise (1) late Eocene ( ) to early Oligocene alluvial fan, braided river, and flood-plain deposits; (2) late Oligocene to early Miocene floodplain and channel deposits; and (3) an early Miocene regressive package of marine to nonmarine sediments. Deposition of synrift sequences corresponded to rifting and extension, which included episodic block faulting and rapid subsidence. Postrift succession comprises (1) an early to middle Miocene regressive package of shallow marine to nonmarine sediments, (2) a late early Miocene transgressive package; and (3) a late Miocene to Pleistocene transgression succession.
NASA Astrophysics Data System (ADS)
Singh, A.; Palombi, D.; Huff, G. F.
2014-12-01
A regional scale study of groundwater flow dynamics was undertaken in the Western Canada Sedimentary Basin (WCSB), comprising parts of Alberta, Saskatchewan and British Columbia. The objective of the study is to investigate basin-scale hydrogeology in WCSB and to establish boundary conditions for future local-scale groundwater management models. Earlier work in the Alberta basin has acknowledged the fact that in addition to topography controlled conditions, a substantial part of the basin exhibits sub-hydrostatic regimes. The basin-scale model (approx. 420,000 km2) includes Upper Cretaceous aquifers to Recent age sediments which collectively attain maximum thicknesses of >2600 m. Regional aquifer units considered for the numerical model are Quaternary sediments, and the sedimentary rocks of the Paskapoo, Scollard, Horseshoe Canyon formations and the Belly River Group. Regional aquitards delineated include the Battle and Bear Paw formations. The study area is bound to the west by the Brazeau-Waptiti thrust belt and to the south by the Canada-USA international border. The boundary to the north and east is delineated by the maximum extent of the Wapiti and Belly River groups and Judith River Formation. USGS MODFLOW was implemented for numerical simulation. The steady state numerical model was calibrated using a Response Surface based (Radial Basis Functions) optimization method. The calibration targets (~2000) were comprised of drill stem tests for deeper units and static water levels for shallower units. Petrophysical analyses of cores averaged K values from analyses of aquifer test results,and literature values were used to provide initial values and calibration ranges for hydraulic properties. Results indicate predominance of topography driven, local- to intermediate-scale flow systems in all hydrostratigraphic units with recharge of these units occurring in the foothills of the Rocky Mountains. The Battle aquitard, where present, acts to retard regional flow
Numerical analysis of the big bounce in loop quantum cosmology
Laguna, Pablo
2007-01-15
Loop quantum cosmology (LQC) homogeneous models with a massless scalar field show that the big-bang singularity can be replaced by a big quantum bounce. To gain further insight on the nature of this bounce, we study the semidiscrete loop quantum gravity Hamiltonian constraint equation from the point of view of numerical analysis. For illustration purposes, we establish a numerical analogy between the quantum bounces and reflections in finite difference discretizations of wave equations triggered by the use of nonuniform grids or, equivalently, reflections found when solving numerically wave equations with varying coefficients. We show that the bounce is closely related to the method for the temporal update of the system and demonstrate that explicit time-updates in general yield bounces. Finally, we present an example of an implicit time-update devoid of bounces and show back-in-time, deterministic evolutions that reach and partially jump over the big-bang singularity.
Numerical analysis of 3-D potential flow in centrifugal turbomachines
NASA Astrophysics Data System (ADS)
Daiguji, H.
1983-09-01
A numerical method is developed for analysing a three-dimensional steady incompressible potential flow through an impeller in centrifugal turbomachines. The method is the same as the previous method which was developed for the axial flow turbomachines, except for some treatments in the downstream region. In order to clarify the validity and limitation of the method, a comparison with the existing experimental data and numerical results is made for radial flow compressor impellers. The calculated blade surface pressure distributions almost coincide with the quasi-3-D calculation by Krimerman and Adler (1978), but are different partly from the quasi-3-D calculation using one meridional flow analysis. It is suggested from this comparison that the flow through an impeller with high efficiency near the design point can be predicted by this fully 3-D numerical method.
Numerical Analysis of Deflections of Multi-Layered Beams
NASA Astrophysics Data System (ADS)
Biliński, Tadeusz; Socha, Tomasz
2015-03-01
The paper concerns the rheological bending problem of wooden beams reinforced with embedded composite bars. A theoretical model of the behaviour of a multi-layered beam is presented. The component materials of this beam are described with equations for the linear viscoelastic five-parameter rheological model. Two numerical analysis methods for the long-term response of wood structures are presented. The first method has been developed with SCILAB software. The second one has been developed with the finite element calculation software ABAQUS and user subroutine UMAT. Laboratory investigations were conducted on sample beams of natural dimensions in order to validate the proposed theoretical model and verify numerical simulations. Good agreement between experimental measurements and numerical results is observed.
Integrated numerical methods for hypersonic aircraft cooling systems analysis
NASA Technical Reports Server (NTRS)
Petley, Dennis H.; Jones, Stuart C.; Dziedzic, William M.
1992-01-01
Numerical methods have been developed for the analysis of hypersonic aircraft cooling systems. A general purpose finite difference thermal analysis code is used to determine areas which must be cooled. Complex cooling networks of series and parallel flow can be analyzed using a finite difference computer program. Both internal fluid flow and heat transfer are analyzed, because increased heat flow causes a decrease in the flow of the coolant. The steady state solution is a successive point iterative method. The transient analysis uses implicit forward-backward differencing. Several examples of the use of the program in studies of hypersonic aircraft and rockets are provided.
Large-scale numerical analysis of three-dimensional seismic waves
NASA Astrophysics Data System (ADS)
Wojcik, G. L.; Vaughan, D. K.
1984-05-01
This report concludes our study of large-scale vectorized numerical analysis applied to time domain seismic wave phenomena in filled basins. Applications include calculations of waves from simple surface or buried sources in a variety of idealized 2-D Basin and Range models (36,000 to 120,000 nodes) described in an interim report, and one large 3-D model (400,000 nodes) from Yucca Flat, Nevada Test Site, described here. Analysis is based on an explicit, finite element, elastic wave solver designed for vectorized execution on the CRAY-1. The primary result of the present 3-D study is that, given the database available from investigations in Yucca Flat, Nevada Test Site, the size of feasible 3-D computational models on the CRAY-1S is adequate to simulate elastic wave fields and interpret arrivals for comparison with existing 3-D ground motion data. Synthetic seismograms from a 400,000 element 3-D simulation of the COALORA event a Yucca Flat indicate that a significant source of transverse motion on radial lines through the source is diffraction from a discontinuity in the Rainier Mesa tuff layer across the Yucca fault. Successful time-domain simulations in 3-D are feasible with pipelined supercomputers but optimal processing requires careful tailoring of the algorithm to vectorize inner code loops and eliminate nonessential arithmetic.
NASA Astrophysics Data System (ADS)
Kim, J.; Kihm, J.; Park, S.; SNU CO2 GEO-SEQ TEAM
2011-12-01
A conventional method, which was suggested by NETL (2007), has been widely used for estimating the geologic storage capacity of carbon dioxide in sedimentary basins. Because of its simple procedure, it has been straightforwardly applied to even spatially very complicate sedimentary basins. Thus, the results from the conventional method are often not accurate and reliable because it can not consider spatial distributions of fluid conditions and carbon dioxide properties, which are not uniform but variable within sedimentary basins. To overcome this limit of the conventional method, a new method, which can consider such spatially variable distributions of fluid conditions and carbon dioxide properties within sedimentary basins, is suggested and applied in this study. In this new method, a three-dimensional geologic formation model of a target sedimentary basin is first established and discretized into volume elements. The fluid conditions (i.e., pressure, temperature, and salt concentration) within each element are then obtained by performing thermo-hydrological numerical modeling. The carbon dioxide properties (i.e., phase, density, dynamic viscosity, and solubility to groundwater) within each element are then calculated from thermodynamic database under corresponding fluid conditions. Finally, the geologic storage capacity of carbon dioxide with in each element is estimated using the corresponding carbon dioxide properties as well as porosity and element volume, and that within the whole sedimentary basin is determined by summation over all elements. This new method is applied to the Bukpyeong Basin, which is one of the prospective offshore sedimentary basins for geologic storage of carbon dioxide in Korea. A three-dimensional geologic formation model of the Bukpyeong Basin is first established considering the elevation data of the boundaries between the geologic formations obtained from seismic survey and geologic maps at the sea floor surface. This geologic
Resource Purpose:The U.S EPA's water programs and their counterparts in states and pollution control agencies are increasingly emphasizing watershed- and water quality-based assessment and integrated analysis of point and nonpoint sources. Better Assessment Science Integra...
Analysis of sludge from Hanford K East Basin canisters
Makenas, B.J.; Welsh, T.L.; Baker, R.B.; Hoppe, E.W.; Schmidt, A.J.; Abrefah, J.; Tingey, J.M.; Bredt, P.R.; Golcar, G.R.
1997-09-12
Sludge samples from the canisters in the Hanford K East Basin fuel storage pool have been retrieved and analyzed. Both chemical and physical properties have been determined. The results are to be used to determine the disposition of the bulk of the sludge and to assess the impact of residual sludge on dry storage of the associated intact metallic uranium fuel elements. This report is a summary and review of the data provided by various laboratories. Although raw chemistry data were originally reported on various bases (compositions for as-settled, centrifuged, or dry sludge) this report places all of the data on a common comparable basis. Data were evaluated for internal consistency and consistency with respect to the governing sample analysis plan. Conclusions applicable to sludge disposition and spent fuel storage are drawn where possible.
Dupree, Jean A.; Crowfoot, Richard M.
2012-01-01
The drainage basin is a fundamental hydrologic entity used for studies of surface-water resources and during planning of water-related projects. Numeric drainage areas published by the U.S. Geological Survey water science centers in Annual Water Data Reports and on the National Water Information Systems (NWIS) Web site are still primarily derived from hard-copy sources and by manual delineation of polygonal basin areas on paper topographic map sheets. To expedite numeric drainage area determinations, the Colorado Water Science Center developed a digital database structure and a delineation methodology based on the hydrologic unit boundaries in the National Watershed Boundary Dataset. This report describes the digital database architecture and delineation methodology and also presents the results of a comparison of the numeric drainage areas derived using this digital methodology with those derived using traditional, non-digital methods. (Please see report for full Abstract)
Accounting for Errors in Model Analysis Theory: A Numerical Approach
NASA Astrophysics Data System (ADS)
Sommer, Steven R.; Lindell, Rebecca S.
2004-09-01
By studying the patterns of a group of individuals' responses to a series of multiple-choice questions, researchers can utilize Model Analysis Theory to create a probability distribution of mental models for a student population. The eigenanalysis of this distribution yields information about what mental models the students possess, as well as how consistently they utilize said mental models. Although the theory considers the probabilistic distribution to be fundamental, there exists opportunities for random errors to occur. In this paper we will discuss a numerical approach for mathematically accounting for these random errors. As an example of this methodology, analysis of data obtained from the Lunar Phases Concept Inventory will be presented. Limitations and applicability of this numerical approach will be discussed.
A numerical analysis of the unsteady flow past bluff bodies
NASA Astrophysics Data System (ADS)
Fernando, M. S. U. K.; Modi, V. J.
1990-01-01
The paper describes in detail a relatively sophisticated numerical approach, using the Boundary Element Method in conjunction with the Discrete Vortex Model, to represent the complex unsteady flow field around a bluff body with separating shear layers. Important steps in the numerical analysis of this challenging problem are discussed and a performance evaluation algorithm established. Of considerable importance is the effect of computational parameters such as number of elements representing the geometry, time-step size, location of the nascent vortices, etc., on the accuracy of results and the associated cost. As an example, the method is applied to the analysis of the flow around a stationary Savonius rotor. A detailed parametric study provides fundamental information concerning the starting torque time histories, evolution of the wake, Strouhal number, etc. A comparison with the wind tunnel test data shows remarkable correlation suggesting considerable promise for the approach.
Numerical simulation of unidirectional irregular nonlinear waves in the basin of intermediate depth
NASA Astrophysics Data System (ADS)
Slunyaev, Alexey; Sergeeva, Anna; Didenkulova, Ira
2016-04-01
waves over intermediate-depth waves, we show that in the situation of very rough sea, the extreme waves possess noticeable front-rear asymmetry in all considered cases. In the situation of modulationaly stable waves, kph ≈ 1 < 1.36, the asymmetry is equally pronounced as in the deeper water situations. Thus the Benjamin - Feir instability seems to be irrelevant for this peculiarity of extreme wave shapes. The results of numerical simulations are discussed in view of available in-situ measurements at shallow regions of the Baltic Sea. [1] A. Sergeeva, A. Slunyaev, Rogue waves, rogue events and extreme wave kinematics in spatio-temporal fields of simulated sea states. Nat. Hazards Earth Syst. Sci. 13, 1759-1771 (2013).
Asymptotic/numerical analysis of supersonic propeller noise
NASA Technical Reports Server (NTRS)
Myers, M. K.; Wydeven, R.
1989-01-01
An asymptotic analysis based on the Mach surface structure of the field of a supersonic helical source distribution is applied to predict thickness and loading noise radiated by high speed propeller blades. The theory utilizes an integral representation of the Ffowcs-Williams Hawkings equation in a fully linearized form. The asymptotic results are used for chordwise strips of the blade, while required spanwise integrations are performed numerically. The form of the analysis enables predicted waveforms to be interpreted in terms of Mach surface propagation. A computer code developed to implement the theory is described and found to yield results in close agreement with more exact computations.
Numerical analysis on thermal drilling of aluminum metal matrix composite
NASA Astrophysics Data System (ADS)
Hynes, N. Rajesh Jesudoss; Maheshwaran, M. V.
2016-05-01
The work-material deformation is very large and both the tool and workpiece temperatures are high in thermal drilling. Modeling is a necessary tool to understand the material flow, temperatures, stress, and strains, which are difficult to measure experimentally during thermal drilling. The numerical analysis of thermal drilling process of aluminum metal matrix composite has been done in the present work. In this analysis the heat flux of different stages is calculated. The calculated heat flux is applied on the surface of work piece and thermal distribution is predicted in different stages during the thermal drilling process.
Sequential analysis of the numerical Stroop effect reveals response suppression.
Cohen Kadosh, Roi; Gevers, Wim; Notebaert, Wim
2011-09-01
Automatic processing of irrelevant stimulus dimensions has been demonstrated in a variety of tasks. Previous studies have shown that conflict between relevant and irrelevant dimensions can be reduced when a feature of the irrelevant dimension is repeated. The specific level at which the automatic process is suppressed (e.g., perceptual repetition, response repetition), however, is less understood. In the current experiment we used the numerical Stroop paradigm, in which the processing of irrelevant numerical values of 2 digits interferes with the processing of their physical size, to pinpoint the precise level of the suppression. Using a sequential analysis, we dissociated perceptual repetition from response repetition of the relevant and irrelevant dimension. Our analyses of reaction times, error rates, and diffusion modeling revealed that the congruity effect is significantly reduced or even absent when the response sequence of the irrelevant dimension, rather than the numerical value or the physical size, is repeated. These results suggest that automatic activation of the irrelevant dimension is suppressed at the response level. The current results shed light on the level of interaction between numerical magnitude and physical size as well as the effect of variability of responses and stimuli on automatic processing. PMID:21500951
Numerical analysis of volcanic SO{sub 2} plume transport
Uno, Itsushi
1996-12-31
Mt. Sakurajima volcano (1060m) located southern part of Kyushu island, Japan, emitted a huge amount of volcanic gas (e.g., 1000-2000 SO{sub 2}-ton/day) and has a strong impact in the environmental SO{sub 2} concentration. This volcanic SO{sub 2} plume transport process over the Kyushu island was simulated by a random walk model based on the wind and turbulence fields simulated by a mesoscale numerical model using four-dimensional data assimilation (FDDA). Continuous four days of numerical simulation was the period covering from May 7 to May 10, 1987. Grided global analysis by ECMWF and the special pilot-balloon observation data were used in the FDDA. Mesoscale numerical model with FDDA simulated well the general wind fields during the passage of high pressure system, and the complicated local wind circulation within the planetary boundary layer (PBL). Simulated surface wind variation was quantitatively compared with the observation data, and showed the good agreements. Numerical results of plume transport process were compared with SO{sub 2} surface and 3-D airborne measurements. It was revealed that simulated three-dimensional plume behavior explained well the observed SO{sub 2} variation, and the day-time development of PBL played an important role for the transport of the volcanic SO{sub 2} aloft to the surface level. Transformation rate from SO{sub 2} to sulfate was also determined from the trajectory by the random walk calculation.
Clustered Numerical Data Analysis Using Markov Lie Monoid Based Networks
NASA Astrophysics Data System (ADS)
Johnson, Joseph
2016-03-01
We have designed and build an optimal numerical standardization algorithm that links numerical values with their associated units, error level, and defining metadata thus supporting automated data exchange and new levels of artificial intelligence (AI). The software manages all dimensional and error analysis and computational tracing. Tables of entities verses properties of these generalized numbers (called ``metanumbers'') support a transformation of each table into a network among the entities and another network among their properties where the network connection matrix is based upon a proximity metric between the two items. We previously proved that every network is isomorphic to the Lie algebra that generates continuous Markov transformations. We have also shown that the eigenvectors of these Markov matrices provide an agnostic clustering of the underlying patterns. We will present this methodology and show how our new work on conversion of scientific numerical data through this process can reveal underlying information clusters ordered by the eigenvalues. We will also show how the linking of clusters from different tables can be used to form a ``supernet'' of all numerical information supporting new initiatives in AI.
NASA Astrophysics Data System (ADS)
de Pablo, M. A.; Márquez, A.; Centeno, J. D.
The Atlantis basin is one of the martian highlands areas where there was proposed the existence of an ancient lake during the early geological history of Mars [1] [2] [3] [4]. The existence of some morphological features inside the basin and in the surrounding area, allow to check the existence of liquid water in the past of the planet. On the other hand, other morphological features indicate the existence of snow and liquid groundwater in recent times. The detailed study of the geomorphologic features allows to make an approach to the hydrological evolution of the Atlantis basin. The study of the geomorphology of this region has been carried out by means of the analysis of MOC high resolution images obtained by the Mars Global Surveyor mission and the THEMIS images, in the visible spectrum, sent by Mars Odyssey spacecrafts. The most clearly morphological feature indicative of the existence of water in the surface of Mars in the past are the numerous channels that end into Atlantis basin from the highest terrains. In addiction to these fluvial channels, the existence of mass flow deposits is also indicative of the existence of water in the area. Some of these slumps are in the internal slopes of impact craters, but others cover huge extensions around the chaotic terrains of the studied area. The lobated ejecta deposits observed in the Atlantis basin region are indicative of the existence of groundwater (solid or liquid) [5]. Serrated reliefs and tables in the borders of the basins are indicative of the existence of a water sheet. Beneath this water sheet some deposits was formed which was eroded, due to the gradual desiccation of the basin, forming the tables and serrated reliefs. The existence of different chaotic terrains in the area implies the existence of huge amounts of water under the surface according to the different models of chaotic terrain formation [6] [7]. The existence of groundwater could be decided by the existence of collapses in the near to the
NASA Astrophysics Data System (ADS)
de Pablo, M. A.; Márquez, A.; Centeno, J. D.
The Atlantis basin is one of the martian highlands areas where there was proposed the existence of an ancient lake during the early geological history of Mars [1] [2] [3] [4]. The existence of some morphological features inside the basin and in the surrounding area, allow to check the existence of liquid water in the past of the planet. On the other hand, other morphological features indicate the existence of snow and liquid groundwater in recent times. The detailed study of the geomorphologic features allows to make an approach to the hydrological evolution of the Atlantis basin. The study of the geomorphology of this region has been carried out by means of the analysis of MOC high resolution images obtained by the Mars Global Surveyor mission and the THEMIS images, in the visible spectrum, sent by Mars Odyssey spacecrafts. The most clearly morphological feature indicative of the existence of water in the surface of Mars in the past are the numerous channels that end into Atlantis basin from the highest terrains. In addiction to these fluvial channels, the existence of mass flow deposits is also indicative of the existence of water in the area. Some of these slumps are in the internal slopes of impact craters, but others cover huge extensions around the chaotic terrains of the studied area. The lobated ejecta deposits observed in the Atlantis basin region are indicative of the existence of groundwater (solid or liquid) [5]. Serrated reliefs and tables in the borders of the basins are indicative of the existence of a water sheet. Beneath this water sheet some deposits was formed which was eroded, due to the gradual desiccation of the basin, forming the tables and serrated reliefs. The existence of different chaotic terrains in the area implies the existence of huge amounts of water under the surface according to the different models of chaotic terrain formation [6] [7]. The existence of groundwater could be decided by the existence of collapses in the near to the
NASA Astrophysics Data System (ADS)
Wahid, Ali; Salim, Ahmed Mohamed Ahmed; Gaafar, Gamal Ragab; Yusoff, Wan Ismail Wan
2016-02-01
Geostatistics or statistical approach is based on the studies of temporal and spatial trend, which depend upon spatial relationships to model known information of variable(s) at unsampled locations. The statistical technique known as kriging was used for petrophycial and facies analysis, which help to assume spatial relationship to model the geological continuity between the known data and the unknown to produce a single best guess of the unknown. Kriging is also known as optimal interpolation technique, which facilitate to generate best linear unbiased estimation of each horizon. The idea is to construct a numerical model of the lithofacies and rock properties that honor available data and further integrate with interpreting seismic sections, techtonostratigraphy chart with sea level curve (short term) and regional tectonics of the study area to find the structural and stratigraphic growth history of the NW Bonaparte Basin. By using kriging technique the models were built which help to estimate different parameters like horizons, facies, and porosities in the study area. The variograms were used to determine for identification of spatial relationship between data which help to find the depositional history of the North West (NW) Bonaparte Basin.
Numerical analysis of free vibrations of damped rotating structures
NASA Technical Reports Server (NTRS)
Gupta, K. K.
1977-01-01
This paper is concerned with the efficient numerical solution of damped and undamped free vibration problems of rotating structures. While structural discretization is achieved by the finite element method, the associated eigenproblem solution is effected by a combined Sturm sequence and inverse iteration technique that enables the computation of a few required roots only without having to compute any other. For structures of complex configurations, a modal synthesis technique is also presented, which is based on appropriate combinations of eigenproblem solution of various structural components. Such numerical procedures are general in nature, which fully exploit matrix sparsity inherent in finite element discretizations, and prove to be most efficient for the vibration analysis of any damped rotating structure, such as rotating machineries, helicopter and turbine blades, spinning space stations, among others.
Numerical Ergonomics Analysis in Operation Environment of CNC Machine
NASA Astrophysics Data System (ADS)
Wong, S. F.; Yang, Z. X.
2010-05-01
The performance of operator will be affected by different operation environments [1]. Moreover, poor operation environment may cause health problems of the operator [2]. Physical and psychological considerations are two main factors that will affect the performance of operator under different conditions of operation environment. In this paper, applying scientific and systematic methods find out the pivot elements in the field of physical and psychological factors. There are five main factors including light, temperature, noise, air flow and space that are analyzed. A numerical ergonomics model has been built up regarding the analysis results which can support to advance the design of operation environment. Moreover, the output of numerical ergonomic model can provide the safe, comfortable, more productive conditions for the operator.
Analysis of Ignition Testing on K-West Basin Fuel
J. Abrefah; F.H. Huang; W.M. Gerry; W.J. Gray; S.C. Marschman; T.A. Thornton
1999-08-10
Approximately 2100 metric tons of spent nuclear fuel (SNF) discharged from the N-Reactor have been stored underwater at the K-Basins in the 100 Area of the Hanford Site. The spent fuel has been stored in the K-East Basin since 1975 and in the K-West Basin since 1981. Some of the SNF elements in these basins have corroded because of various breaches in the Zircaloy cladding that occurred during fuel discharge operations and/or subsequent handling and storage in the basins. Consequently, radioactive material in the fuel has been released into the basin water, and water has leaked from the K-East Basin into the soil below. To protect the Columbia River, which is only 380 m from the basins, the SNF is scheduled to be removed and transported for interim dry storage in the 200 East Area, in the central portion of the Site. However, before being shipped, the corroded fuel elements will be loaded into Multi-Canister OverPacks and conditioned. The conditioning process will be selected based on the Integrated Process Strategy (IPS) (WHC 1995), which was prepared on the basis of the dry storage concept developed by the Independent Technical Assessment (ITA) team (ITA 1994).
Analysis of runoff from small drainage basins in Wyoming
Craig, Gordon S.; Rankl, James G.
1978-01-01
A flood-hydrograph study has defined the magnitude and frequency of flood volumes and flood peaks that can be expected from drainage basins smaller than 11 square miles in the plains and valley areas of Wyoming. Rainfall and runoff data, collected for 9 years on a seasonal basis (April through September), were used to calibrate a rainfall-runoff model on each of 22 small basins. Long-term records of runoff volume and peak discharge were synthesized for these 22 basins. Flood volumes and flood peaks of specific recurrence intervals (2, 5, 10, 25, 50, and 100 years) were then related to basin characteristics with a high degree of correlation. Flood volumes were related to drainage area, maximum relief, and basin slope. Flood peaks were related to drainage area, maximum relief, basin slope, and channel slope. An investigation of ponding behind a highway embankment, with available storage capacity and with a culvert to allow outflow, has shown that the single fast-rising peak is most important in culvert design. Consequently, a dimensionless hydrograph defines the characteristic shape of flood hydrographs to be expected from small drainage basins in Wyoming. For design purposes, a peak and volume can be estimated from basin characteristics and used with the dimensionless hydrograph to produce a synthetic single-peak hydrograph. Incremental discharges of the hydrograph can be routed along a channel, where a highway fill and culvert are to be placed, to help determine the most economical size of culvert if embankment storage is to be considered.
Numeral-Incorporating Roots in Numeral Systems: A Comparative Analysis of Two Sign Languages
ERIC Educational Resources Information Center
Fuentes, Mariana; Massone, Maria Ignacia; Fernandez-Viader, Maria del Pilar; Makotrinsky, Alejandro; Pulgarin, Francisca
2010-01-01
Numeral-incorporating roots in the numeral systems of Argentine Sign Language (LSA) and Catalan Sign Language (LSC), as well as the main features of the number systems of both languages, are described and compared. Informants discussed the use of numerals and roots in both languages (in most cases in natural contexts). Ten informants took part in…
Ernest Mancini
2001-03-01
Part 3 (Petroleum System Modeling of the Jurassic Smackover Formation) objectives are to provide an analysis of the Smackover petroleum system in Years 4 and 5 of the project and to transfer effectively the research results to producers through workshops and topical reports. Work Accomplished (Year 5): Task 1 - Basin Flow - Basin flow modeling has been completed and the topical report has been submitted to the U.S. DOE for review. Task 2 - Petroleum Source Rocks - Work on the characterization of Smackover petroleum source rocks has been integrated into the basin flow model. The information on the source rocks is being prepared for inclusion in the final report. Task 3 - Petroleum Reservoirs - Work on the characterization of Smackover petroleum reservoirs continues. The cores to be described have been identified and many of the cores for the eastern and western parts of the basin have been described. Task 4 - Reservoir Diagenesis - Work on reservoir diagenesis continues. Samples from the cores selected for the reservoir characterization are being used for this task. Task 5 - Underdeveloped Reservoirs - Two underdeveloped Smackover reservoirs have been identified. They are the microbial reef and shoal reservoirs. Work Planned (Year 5): Task 1 - Basin Flow - This task has been completed and the topical report has been submitted to the U.S. DOE. Task 2 - Petroleum Source Rocks - Petroleum source rock information will continue to be prepared for the final report. Task 3 - Petroleum Reservoirs - Characterization of petroleum reservoirs will continue through core studies. Task 4 - Reservoir Diagenesis - Characterization of reservoir diagenesis will continue through petrographic analysis. Task 5 - Underdeveloped Reservoirs - Study of Smackover underdeveloped reservoirs will continue with focus on the microbial reef and shoal reservoirs.
Unsaturated Shear Strength and Numerical Analysis Methods for Unsaturated Soils
NASA Astrophysics Data System (ADS)
Kim, D.; Kim, G.; Kim, D.; Baek, H.; Kang, S.
2011-12-01
The angles of shearing resistance(φb) and internal friction(φ') appear to be identical in low suction range, but the angle of shearing resistance shows non-linearity as suction increases. In most numerical analysis however, a fixed value for the angle of shearing resistance is applied even in low suction range for practical reasons, often leading to a false conclusion. In this study, a numerical analysis has been undertaken employing the estimated shear strength curve of unsaturated soils from the residual water content of SWCC proposed by Vanapalli et al.(1996). The result was also compared with that from a fixed value of φb. It is suggested that, in case it is difficult to measure the unsaturated shear strength curve through the triaxial soil tests, the estimated shear strength curve using the residual water content can be a useful alternative. This result was applied for analyzing the slope stablity of unsaturated soils. The effects of a continuous rainfall on slope stability were analyzed using a commercial program "SLOPE/W", with the coupled infiltration analysis program "SEEP/W" from the GEO-SLOPE International Ltd. The results show that, prior to the infiltration by the intensive rainfall, the safety factors using the estimated shear strength curve were substantially higher than that from the fixed value of φb at all time points. After the intensive infiltration, both methods showed a similar behavior.
An improved numerical model for wave rotor design and analysis
NASA Technical Reports Server (NTRS)
Paxson, Daniel E.; Wilson, Jack
1992-01-01
A numerical model has been developed which can predict both the unsteady flows within a wave rotor and the steady averaged flows in the ports. The model is based on the assumptions of one-dimensional, unsteady, and perfect gas flow. Besides the dominant wave behavior, it is also capable of predicting the effects of finite tube opening time, leakage from the tube ends, and viscosity. The relative simplicity of the model makes it useful for design, optimization, and analysis of wave rotor cycles for any application. This paper discusses some details of the model and presents comparisons between the model and two laboratory wave rotor experiments.
Numerical analysis of decoy state quantum key distribution protocols
Harrington, Jim W; Rice, Patrick R
2008-01-01
Decoy state protocols are a useful tool for many quantum key distribution systems implemented with weak coherent pulses, allowing significantly better secret bit rates and longer maximum distances. In this paper we present a method to numerically find optimal three-level protocols, and we examine how the secret bit rate and the optimized parameters are dependent on various system properties, such as session length, transmission loss, and visibility. Additionally, we show how to modify the decoy state analysis to handle partially distinguishable decoy states as well as uncertainty in the prepared intensities.
Srisuk, K; Sriboonlue, V; Buaphan, C; Archvichai, L; Youngme, W; Satarak, P; Jaruchaikul, S
2001-01-01
The objective of the project is to establish a conceptual groundwater model over the lower Nam Kam Basin in order to apply a numerical technique for the prediction of the impact of saline water transport due to the proposed weir across the Nam Kam River. Hydrogeological investigations including mapping, drilling, piezometer installations and monitoring were systematically conducted during 1997 to 1998. Brackish groundwater is saturated under the area with a depth of 30-60 m. Groundwater regionally flows from the south (the Phu Phan Range) to the north and discharges to the Nam Kam River. Another direction is from the northern region to the southern region, discharging to the central region. A two-dimensional model was constructed along the principal gradient in the NW-SE direction. There are several local recharge and discharge areas across the Nam Kam floodplain. A local groundwater flow is active within the depth of 2 m to 30 m below the ground surface within the sand and gravel unit. Simulations were calibrated with hydraulic heads and salinity of groundwater in the piezometers. It is found that the recharge and evapotranspiration rates are 1% to 40% of the rainfall and 10% to 15% of a pan evaporation, respectively. The ranges of horizontal hydraulic conductivity to vertical hydraulic conductivity are 0.1 to 0.01. The possible longitudinal dispersivity values of the hydrostratigraphic units are 20 m to 500 m, but the transverse dispersivity is less than the longitude by one order of magnitude. The comparison of calculated heads and measured heads give a root mean square error of less than 1 m. The different salinity concentrations are still in a range of 2000-5000 mg/l. Ten year simulation of saline water transport indicates that the reservoir ponding with water level at +140.5 m above mean sea level may divert groundwater flow and discharging to the northern boundary of the reservoir at Ban Don Kao. PMID:11724482
Geologic Analysis of Priority Basins for Exploration and Drilling
Carroll, H.B.; Reeves, T.K.
1999-04-27
There has been a substantial decline in both exploratory drilling and seismic field crew activity in the United States over the last 10 years, due primarily to the declining price of oil. To reverse this trend and to preserve the entrepreneurial independent operator, the U.S. DOE is attempting to encourage hydrocarbon exploration activities in some of the under exploited regions of the United States. This goal is being accomplished by conducting broad regional reviews of potentially prospective areas within the lower 48 states. Data are being collected on selected areas, and studies are being done on a regional scale generally unavailable to the smaller independent. The results of this work will be made available to the public to encourage the undertaking of operations in areas which have been overlooked until this project. Fifteen criteria have been developed for the selection of study areas. Eight regions have been identified where regional geologic analysis will be performed. This report discusses preliminary findings concerning the geology, early tectonic history, structure and potential unconventional source rocks for the Black Mesa basin and South Central states region, the two highest priority study areas.
An analysis of stream temperatures, Green River Basin, Wyoming
Lowham, H.W.
1978-01-01
A method for estimating temperatures of streams in the Green River basin, Wyoming, utilizes a regional model for estimating mean daily temperatures of streams at unmeasured sites. The regional model was developed by describing annual temperature patterns at 43 measured sites and by applying the harmonic function T = M + A -sin (0.0172 t + C)- where: T is mean daily temperature; M, A, and C are harmonic coefficients calculated from data for each stream-temperature station; and t is the day of the water year. Application of the equation for estimating temperatures at unmeasured sites requires regionalized estimates of M, A, and C. Regional estimates were developed with the aid of multiple-regression techniques, whereby the calculated harmonic coefficients were regressed against physical and climatic characteristics of the stream-temperature stations. Stream elevation was a significant factor affecting water temperature. Analysis of areal and temporal variations in temperature showed that springs, irrigation return flows, and reservoir storage were affecting reaches of several major streams. (Woodard-USGS)
Numerical Analysis on Air Ingress Behavior in GTHTR300H
Tetsuaki Takeda; Xing Yan; Kazuhiko Kunitomi
2006-07-01
Japan Atomic Energy Agency (JAEA) has been developing the analytical code for the safety characteristics of the HTGR and carrying out design study of the gas turbine high temperature reactor of 300 MWe nominal-capacity for hydrogen production, the GTHTR300H (Gas Turbine High Temperature Reactor 300 for Hydrogen). The objective of this study is to clarify safety characteristics of the GTHTR300H for the pipe rupture accident. A numerical analysis of heat and mass transfer fluid flow with multi-component gas mixture has been performed to obtain the variation of the density of the gas mixture, and the onset time of natural circulation of air. From the results obtained in this analysis, it was found that the duration time of the air ingress by molecular diffusion would increase due to the existence of the recuperator in the GTHTR300H system. (authors)
Numerical analysis of cocurrent conical and cylindrical axial cyclone separators
NASA Astrophysics Data System (ADS)
Nor, M. A. M.; Al-Kayiem, H. H.; Lemma, T. A.
2015-12-01
Axial concurrent liquid-liquid separator is seen as an alternative unit to the traditional tangential counter current cyclone due to lower droplet break ups, turbulence and pressure drop. This paper presents the numerical analysis of a new conical axial cocurrent design along with a comparison to the cylindrical axial cocurrent type. The simulation was carried out using CFD technique in ANSYS-FLUENT software. The simulation results were validated by comparison with experimental data from literature, and mesh independency and quality were performed. The analysis indicates that the conical version achieves better separation performance compared to the cylindrical type. Simulation results indicate tangential velocity with 8% higher and axial velocity with 80% lower recirculation compared to the cylindrical type. Also, the flow visualization counters shows smaller recirculation region relative to the cylindrical unit. The proposed conical design seems more efficient and suits the crude/water separation in O&G industry.
Asymptotic and numerical analysis of electrohydrodynamic flows of dielectric liquid.
Suh, Y K; Baek, K H; Cho, D S
2013-08-01
We perform an asymptotic analysis of electrohydrodynamic (EHD) flow of nonpolar liquid subjected to an external, nonuniform electric field. The domain of interest covers the bulk as well as the thin dissociation layers (DSLs) near the electrodes. Outer (i.e., bulk) equations for the ion transport in hierarchical order of perturbation parameters can be expressed in linear form, whereas the inner (i.e., DSL) equations take a nonlinear form. We derive a simple formula in terms of various parameters which can be used to estimate the relative importance of the DSL-driven flow compared with the bulk-driven flow. EHD flow over a pair of cylindrical electrodes is then solved asymptotically and numerically. It is found that in large geometric scale and high ion concentration the EHD flow is dominated by the bulk-charge-induced flow. As the scale and concentration are decreased, the DSL-driven slip velocity increases and the resultant flow tends to dominate the domain and finally leads to flow reversal. We also conduct a flow-visualization experiment to verify the analysis and attain good agreement between the two results with parameter tuning. We finally show, based on the comparison of experimental and numerical solutions, that the rate of free-ion generation (dissociation) should be less than the one predicted from the existing formula. PMID:24032920
Numerical analysis of distortion characteristics of heterojunction bipolar transistor laser
NASA Astrophysics Data System (ADS)
Piramasubramanian, S.; Ganesh Madhan, M.; Nagella, Jyothsna; Dhanapriya, G.
2015-12-01
Numerical analysis of harmonic and third order intermodulation distortion of transistor laser is presented in this paper. The three level rate equations are numerically solved to determine the modulation and distortion characteristics. DC and AC analysis on the device are carried out to determine its power-current and frequency response characteristics. Further, the effects of quantum well recombination time and electron capture time in the quantum well, on the modulation depth and distortion characteristics are examined. It is observed that the threshold current density of the device decreases with increasing electron lifetime, which coincides with earlier findings. Also, the magnitude of harmonic distortion and intermodulation products are found to reduce with increasing current density and with a reduction of spontaneous emission recombination lifetime. However, an increase of electron capture time improves the distortion performance. A maximum modulation depth of 18.42 dB is obtained for 50 ps spontaneous emission life time and 1 ps electron capture time, for 2.4 GHz frequency at a current density of 2Jth. A minimum second harmonic distortion magnitude of -66.8 dBc is predicted for 50 ps spontaneous emission life time and 1 ps electron capture time for 2.4 GHz frequency, at a current density of 7Jth. Similarly, a minimum third order intermodulation distortion of -83.93 dBc is obtained for 150 ps spontaneous emission life time and 5 ps electron capture time under similar biasing conditions.
Numerical analysis and experimental verification of vehicle trajectories
NASA Astrophysics Data System (ADS)
Wekezer, J. W.; Cichocki, K.
2003-09-01
The paper presents research results of a study, in which computational mechanics was utilized to predict vehicle trajectories upon traversing standard Florida DOT street curbs. Computational analysis was performed using LS-DYNA non-linear, finite element computer code with two public domain, finite element models of motor vehicles: Ford Festiva and Ford Taurus. Shock absorbers were modeled using discrete spring and damper elements. Connections for the modifie suspension systems were carefully designed to assure proper range of motion for the suspension models. Inertia properties of the actual vehicles were collected using tilt-table tests and were used for LS-DYNA vehicle models. Full-scale trajectory tests have been performed at Texas Transportation Institute to validate the numerical models and predictions from computational mechanics. Experiments were conducted for Ford Festiva and Ford Taurus, both for two values of approach angle: 15 and 90 degrees, with impact velocity of 45 mph. Experimental data including accelerations, displacements and overall vehicles behavior were collected by high-speed video cameras and have e been compared with numerical results. Verification results indicated a good correlation between computational analysis and full-scale test data. The study also underlined a strong dependence of properly modeled suspension and tires on resulting vehicle trajectories.
Numerical analysis of modified Central Solenoid insert design
Khodak, Andrei; Martovetsky, Nicolai; Smirnov, Aleksandre; Titus, Peter
2015-06-21
The United States ITER Project Office (USIPO) is responsible for fabrication of the Central Solenoid (CS) for ITER project. The ITER machine is currently under construction by seven parties in Cadarache, France. The CS Insert (CSI) project should provide a verification of the conductor performance in relevant conditions of temperature, field, currents and mechanical strain. The US IPO designed the CSI that will be tested at the Central Solenoid Model Coil (CSMC) Test Facility at JAEA, Naka. To validate the modified design we performed three-dimensional numerical simulations using coupled solver for simultaneous structural, thermal and electromagnetic analysis. Thermal and electromagnetic simulations supported structural calculations providing necessary loads and strains. According to current analysis design of the modified coil satisfies ITER magnet structural design criteria for the following conditions: (1) room temperature, no current, (2) temperature 4K, no current, (3) temperature 4K, current 60 kA direct charge, and (4) temperature 4K, current 60 kA reverse charge. Fatigue life assessment analysis is performed for the alternating conditions of: temperature 4K, no current, and temperature 4K, current 45 kA direct charge. Results of fatigue analysis show that parts of the coil assembly can be qualified for up to 1 million cycles. Distributions of the Current Sharing Temperature (TCS) in the superconductor were obtained from numerical results using parameterization of the critical surface in the form similar to that proposed for ITER. Lastly, special ADPL scripts were developed for ANSYS allowing one-dimensional representation of TCS along the cable, as well as three-dimensional fields of TCS in superconductor material. Published by Elsevier B.V.
Numerical analysis of modified Central Solenoid insert design
Khodak, Andrei; Martovetsky, Nicolai; Smirnov, Aleksandre; Titus, Peter
2015-06-21
The United States ITER Project Office (USIPO) is responsible for fabrication of the Central Solenoid (CS) for ITER project. The ITER machine is currently under construction by seven parties in Cadarache, France. The CS Insert (CSI) project should provide a verification of the conductor performance in relevant conditions of temperature, field, currents and mechanical strain. The US IPO designed the CSI that will be tested at the Central Solenoid Model Coil (CSMC) Test Facility at JAEA, Naka. To validate the modified design we performed three-dimensional numerical simulations using coupled solver for simultaneous structural, thermal and electromagnetic analysis. Thermal and electromagneticmore » simulations supported structural calculations providing necessary loads and strains. According to current analysis design of the modified coil satisfies ITER magnet structural design criteria for the following conditions: (1) room temperature, no current, (2) temperature 4K, no current, (3) temperature 4K, current 60 kA direct charge, and (4) temperature 4K, current 60 kA reverse charge. Fatigue life assessment analysis is performed for the alternating conditions of: temperature 4K, no current, and temperature 4K, current 45 kA direct charge. Results of fatigue analysis show that parts of the coil assembly can be qualified for up to 1 million cycles. Distributions of the Current Sharing Temperature (TCS) in the superconductor were obtained from numerical results using parameterization of the critical surface in the form similar to that proposed for ITER. Lastly, special ADPL scripts were developed for ANSYS allowing one-dimensional representation of TCS along the cable, as well as three-dimensional fields of TCS in superconductor material. Published by Elsevier B.V.« less
Analysis of runoff from small drainage basins in Wyoming
Craig, Gordon S.; Rankl, James G.
1977-01-01
A flood-hydrograph study has defined the magnitude and frequency of flood volumes and flood peaks that can be expected from drainage basins smaller than 11 square miles in the plains and valley areas of Wyoming. Rainfall and runoff data, collected for 9 years on a seasonal basis (April through September), were used to calibrate a rainfall-runoff model on each of 22 small basins. Long-term records of runoff volume and peak discharge were synthesized for these 22 basins. Flood volumes and flood peaks of specific recurrence intervals (2, 5, 10, 25, 50, and 100 years) were then related to basin characteristics with a high degree of correlation. Flood volumes were related to drainage area, maximum relief, and basin slope. Flood peaks were related to drainage area, maximum relief, basin slope, and channel slope. An investigation of ponding behind a highway embankment, with available storage capacity and with a culvert to allow outflow, has shown that the single fast-rising peak is most important in culvert design. Consequently, a dimensionless hydrograph defines the characteristic shape of flood hydrographs to be expected from small drainage basins in Wyoming. For design purposes, a peak and volume can be estimated from basin characteristics and used with the dimensionless hydrograph to produce a synthetic single-peak hydrograph. Incremental discharges of the hydrograph can be routed along a channel, where a highway fill and culvert are to be placed, to help determine the most economical size of culvert if embankment storage is to be considered. (Woodard-USGS)
Analysis of urban storm-water quality for seven basins near Portland, Oregon
Miller, Timothy L.; McKenzie, Stuart W.
1978-01-01
Over a 1.5-year period, water-quality data were collected for seven small drainage basins in urban aeas of Portland, Oreg. Analysis of the data followed three approaches. First, the constituent concentrations were analyzed. Average concentrations of suspended sediment, settleable solids, and fecal coliform bacteria generally exceeded levels expected for secondary waste-treatment plant effluent, whereas biochemical oxygen demand concentrations were lower than expected. The second analytical approach established correlations and bivariate regression relationships between constituents for individual storms in each basin, for all storms in each basin, and for all storms in all basins. Generally, correlation coefficients decreased when progressing from data for individual storms in each basin, to data for all storms in each basin, to data for all storms in all basins. In the third approach, storm yields for 10 constituents were related to basin and precipitation characteristics by use of multiple-linear-regression techniques. Storm yields for suspended sediment varied by about four orders of magnitude. Generally, results of the multiple-regression analysis indicated that variations in storm yields were highly dependent on precipitation characteristics, with total rainfall of the storm frequently explaining most of the variation of the dependent variable. (Woodard-USGS)
Analysis of urban storm-water quality for seven basins near Portland, Oregon
Miller, Timothy L.; McKenzie, Stuart W.
1978-01-01
Over a 1.5-year period, water-quality data were collected for seven small drainage basins in urban aeas of Portland, Oreg. Analysis of the data followed three approaches. First, the constituent concentrations were analyzed. Average concentrations of suspended sediment, settleable solids, and fecal coliform bacteria generally exceeded levels expected for secondary waste-treatment plant effluent, whereas biochemical oxygen demand concentrations were lower than expected. The second analytical approach established correlations and bivariate regression relationships between constituents for individual storms in each basin, for all storms in each basin, and for all storms in all basins. Generally, correlation coefficients decreased when progressing from data for individual storms in each basin, to data for all storms in each basin, to data for all storms in all basins. In the third approach, storm yields for 10 constituents were related to basin and precipitation characteristics by use of multiple-linear-regression techniques. Storm yields for suspended sediment varied by about four orders of magnitude. Generally, results of the multiple-regression analysis indicated that variations in storm yields were highly dependent on precipitation characteristics, with total rainfall of the storm frequently explaining most of the variation of the dependent variable.
Application of GIS and RS for Morphometric Analysis of Upper Bhima Basin: A Case Study
NASA Astrophysics Data System (ADS)
Pawar, Amol D.; Sarup, Jyoti; Mittal, Sushil Kumar
2014-12-01
This study presents a morphometric analysis of Upper Bhima Basin (UBB), located in state of Maharahstra, India. Study area is in western part of Maharashtra State, which has a huge socio—economic impact as many towns and metros are emerged as important centres for employment, industrial hubs, and Information Technology (IT) parks. The study focuses only on the morphometric analysis of UBB. Analysis done using ArcGIS software, by digitizing the toposheets, georeferencing them and then analyzing in the GIS environment. The analysis revealed that the basin was of seventh order with dendritic type of drainage pattern. Results revealed that the value of bifurcation ratio Rb lies between 3 and 5. Values of drainage density range from 1.60 to 0.01 km/km2, indicating low drainage density. Average value of drainage density is 0.374 km/km2 for entire basin, so classifying the basin as coarse.
105-N basin sediment disposition phase-two sampling and analysis plan
Smith, R. C.
1997-03-14
The sampling and analysis plan for Phase 2 of the 105-N Basin sediment disposition task defines the sampling and analytical activities that will be performed to support characterization of the sediment and selection of an appropriate sediment disposal option.
TCLP Preparation and Analysis of K East Basin Composite Sludge Samples
Silvers, Kurt L.
2000-08-15
This report contains results from TCLP preparation and analysis of K East Basin floor and canister composite sludge samples. Analyses were performed in the Radiochemical Processing Laboratory (PNNL, 325 Building).
NASA Technical Reports Server (NTRS)
Smith, Eric A.; Einaudi, Franco (Technical Monitor)
2001-01-01
A comprehensive understanding of the meteorological and microphysical nature of Mediterranean storms requires a combination of in situ data analysis, radar data analysis, and satellite data analysis, effectively integrated with numerical modeling studies at various scales. An important aspect of understanding microphysical controls of severe storms, is first understanding the meteorological controls under which a storm has evolved, and then using that information to help characterize the dominant microphysical processes. For hazardous Mediterranean storms, highlighted by the October 5-6, 1998 Friuli flood event in northern Italy, a comprehensive microphysical interpretation requires an understanding of the multiple phases of storm evolution. This involves intense convective development, Sratiform decay, orographic lifting, and sloped frontal lifting processes, as well as the associated vertical motions and thermodynamical instabilities governing physical processes that effect details of the size distributions and fall rates of the various types of hydrometeors found within the storm environment. This talk overviews the microphysical elements of a severe Mediterranean storm in such a context, investigated with the aid of TRMM satellite and other remote sensing measurements, but guided by a nonhydrostatic mesoscale model simulation of the Friuli flood event. The data analysis for this paper was conducted by my research groups at the Global Hydrology and Climate Center in Huntsville, AL and Florida State University in Tallahassee, and in collaboration with Dr. Alberto Mugnai's research group at the Institute of Atmospheric Physics in Rome. The numerical modeling was conducted by Professor Oreg Tripoli and Ms. Giulia Panegrossi at the University of Wisconsin in Madison, using Professor Tripoli's nonhydrostatic modeling system (NMS). This is a scalable, fully nested mesoscale model capable of resolving nonhydrostatic circulations from regional scale down to cloud scale
Stochastic algorithms for the analysis of numerical flame simulations
Bell, John B.; Day, Marcus S.; Grcar, Joseph F.; Lijewski, Michael J.
2004-04-26
Recent progress in simulation methodologies and high-performance parallel computers have made it is possible to perform detailed simulations of multidimensional reacting flow phenomena using comprehensive kinetics mechanisms. As simulations become larger and more complex, it becomes increasingly difficult to extract useful information from the numerical solution, particularly regarding the interactions of the chemical reaction and diffusion processes. In this paper we present a new diagnostic tool for analysis of numerical simulations of reacting flow. Our approach is based on recasting an Eulerian flow solution in a Lagrangian frame. Unlike a conventional Lagrangian view point that follows the evolution of a volume of the fluid, we instead follow specific chemical elements, e.g., carbon, nitrogen, etc., as they move through the system . From this perspective an ''atom'' is part of some molecule of a species that is transported through the domain by advection and diffusion. Reactions cause the atom to shift from one chemical host species to another and the subsequent transport of the atom is given by the movement of the new species. We represent these processes using a stochastic particle formulation that treats advection deterministically and models diffusion and chemistry as stochastic processes. In this paper, we discuss the numerical issues in detail and demonstrate that an ensemble of stochastic trajectories can accurately capture key features of the continuum solution. The capabilities of this diagnostic are then demonstrated by applications to study the modulation of carbon chemistry during a vortex-flame interaction, and the role of cyano chemistry in rm NO{sub x} production for a steady diffusion flame.
Numerical analysis of impact-damaged sandwich composites
NASA Astrophysics Data System (ADS)
Hwang, Youngkeun
Sandwich structures are used in a wide variety of structural applications due to their relative advantages over other conventional structural materials in terms of improved stability, weight savings, and ease of manufacture and repair. Foreign object impact damage in sandwich composites can result in localized damage to the facings, core, and core-facing interface. Such damage may result in drastic reductions in composite strength, elastic moduli, and durability and damage tolerance characteristics. In this study, physically-motivated numerical models have been developed for predicting the residual strength of impact-damaged sandwich composites comprised of woven-fabric graphite-epoxy facesheets and Nomex honeycomb cores subjected to compression-after-impact loading. Results from non-destructive inspection and destructive sectioning of damaged sandwich panels were used to establish initial conditions for damage (residual facesheet indentation, core crush dimension, etc.) in the numerical analysis. Honeycomb core crush test results were used to establish the nonlinear constitutive behavior for the Nomex core. The influence of initial facesheet property degradation and progressive loss of facesheet structural integrity on the residual strength of impact-damaged sandwich panels was examined. The influence of damage of various types and sizes, specimen geometry, support boundary conditions, and variable material properties on the estimated residual strength is discussed. Facesheet strains from material and geometric nonlinear finite element analyses correlated relatively well with experimentally determined values. Moreover, numerical predictions of residual strength are consistent with experimental observations. Using a methodology similar to that presented in this work, it may be possible to develop robust residual strength estimates for complex sandwich composite structural components with varying levels of in-service damage. Such studies may facilitate sandwich
Xu, Hua-Shan; Xu, Zong-Xue; Tang, Fang-Fang; Yu, Wei-Dong; Cheng, Yan-Ping
2012-02-01
In this study, several statistical methods including cluster analysis, seasonal Kendall test, factor analysis/principal component analysis and principal component regression were used to evaluate the spatiotemporal variation of water quality and identify the sources of water pollution in the Zhangweinan River basin. Results of spatial cluster analysis and principal component analysis indicated that the Zhangweinan River basin can be classified into two regions. One is the Zhang River upstream located in the northwest of the Zhangweinan River basin where water quality is good. The other one covers the Wei River and eastern plain of the Zhangweinan River basin, where water is seriously polluted. In this region, pollutants from point sources flow into the river and the water quality changes greatly. Results of temporal cluster analysis and seasonal Kendall test indicated that the study periods may be classified into three periods and two different trends were detected during the period of 2002-2009. The first period was the year of 2002-2003, during which water quality had deteriorated and serious pollution was observed in the Wei river basin and eastern plain of the Zhangweinan River basin. The second period was the year of 2004-2006, during which water quality became better. The year of 2007-2009 is the third period, during which water quality had been improved greatly. Despite that water quality in the Zhangweinan River basin had been improved during the period of 2004-2009, the water quality in the Wei River (southwestern part of the basin), the Wei Canal River and the Zhangweixin River (eastern plain of the basin) is still poor. Principal component analysis and multi-linear regression of the absolute principal component scores showed that the main pollutants of the Zhangweinan River basin came from point source discharge such as heavy industrial wastewater, municipal sewage, chemical industries wasterwater and mine drainage in upstream. Non-point source pollution
NASA Astrophysics Data System (ADS)
Tepe, Çiǧdem; Sözbilir, Hasan
2016-04-01
The purpose of this study is to discuss the geological and geomorphological features of active faults controlling Kemalpaşa Basin. The study consists of basin-bounding faults expressions, kinematic and geomorphic analysis. Kemalpaşa Basin, which is approximately ENE trending and asymmetric graben is located in the southern part of Gediz Graben. Menderes Massif and Bornova Complex comprise the basement rocks of basin. Kızılca Formation, Sütçüler Formation and Alluvium uncomformably overlie the basement rocks. Kemalpaşa Basin which is one of the Quaternary basin in the Western Anatolia Extensional Province was developed at the structural border of the Spildaǧı Fault Zone in the north and the Kemalpaşa Fault in the south. Both the north and south margin-bounding faults of Kemalpaşa Basin are oblique-slip normal faults. According to the results of kinematic analysis, Kemalpaşa Basin has been formed under a NE-GW trending extensional tectonic regime. The variation in the relative degree of tectonic activity in Kemalpaşa Basin and its surroundings were interpreted a detailed geomorphic study of the fault-generated mountain fronts and drainage pattern of the both sides. To identify the impacts of active faults controlling the north and south margins of Kemalpaşa Basin on the geomorphological evolution, the geomorphic indices such as drainage basin geometries, triangular facets, axial river profiles have been determined and the degree of tectonic activity in the both sides of Kemalpaşa Basin has been numerically defined using morphometric indexes such as asymmetry factor (AF), hypsometric curve and integral (HI), valley floor width-to-height ratio (Vf) and mountain front sinuosity (Smf). In morphometric analysis, the both sides of the basin were investigated separating into two segments as the west and east. The values of HI (0,28-0,60), Vf (0,27-0,60) and Smf (1,3) calculated for the western part of the north margin compared with the values of HI (0
Theoretical and Numerical Assessment of Strain Pattern Analysis
NASA Astrophysics Data System (ADS)
Milne, R. D.; Simpson, A.
1996-04-01
The Strain Pattern Analysis (SPA) method was conceived at the RAE in the 1970s as a means of estimating the displacement shape of a helicopter rotor blade by using only strain gauge data, but no attempt was made to provide theoretical justification for the procedure. In this paper, the SPA method is placed on a firm mathematical basis by the use of vector space theory. It is shown that the natural normwhich underlies the SPA projection is the strain energy functionalof the structure under consideration. The natural norm is a weightedversion of the original SPA norm. Numerical experiments on simple flexure and coupled flexure-torsion systems indicate that the use of the natural norm yields structural deflection estimates of significantly greater accuracy than those obtained from the original SPA procedure and that measurement error tolerance is also enhanced. Extensive numerical results are presented for an emulation of the SPA method as applied to existing mathematical models of the main rotor of the DRA Lynx ZD559 helicopter. The efficacy of SPA is demonstrated by using a quasi-linear rotor model in the frequency domain and a fully non-linear, kinematically exact model in the time domain: the procedure based on the natural (or weighted) norm is again found to be superior to that based on the original SPA method, both in respect of displacement estimates and measurement error tolerance.
Numerical model of solar dynamic radiator for parametric analysis
NASA Technical Reports Server (NTRS)
Rhatigan, Jennifer L.
1989-01-01
Growth power requirements for Space Station Freedom will be met through addition of 25 kW solar dynamic (SD) power modules. The SD module rejects waste heat from the power conversion cycle to space through a pumped-loop, multi-panel, deployable radiator. The baseline radiator configuration was defined during the Space Station conceptual design phase and is a function of the state point and heat rejection requirements of the power conversion unit. Requirements determined by the overall station design such as mass, system redundancy, micrometeoroid and space debris impact survivability, launch packaging, costs, and thermal and structural interaction with other station components have also been design drivers for the radiator configuration. Extensive thermal and power cycle modeling capabilities have been developed which are powerful tools in Station design and analysis, but which prove cumbersome and costly for simple component preliminary design studies. In order to aid in refining the SD radiator to the mature design stage, a simple and flexible numerical model was developed. The model simulates heat transfer and fluid flow performance of the radiator and calculates area mass and impact survivability for many combinations of flow tube and panel configurations, fluid and material properties, and environmental and cycle variations. A brief description and discussion of the numerical model, it's capabilities and limitations, and results of the parametric studies performed is presented.
Numerical Analysis of Film Cooling at High Blowing Ratio
NASA Technical Reports Server (NTRS)
El-Gabry, Lamyaa; Heidmann, James; Ameri, Ali
2009-01-01
Computational Fluid Dynamics is used in the analysis of a film cooling jet in crossflow. Predictions of film effectiveness are compared with experimental results for a circular jet at blowing ratios ranging from 0.5 to 2.0. Film effectiveness is a surface quantity which alone is insufficient in understanding the source and finding a remedy for shortcomings of the numerical model. Therefore, in addition, comparisons are made to flow field measurements of temperature along the jet centerline. These comparisons show that the CFD model is accurately predicting the extent and trajectory of the film cooling jet; however, there is a lack of agreement in the near-wall region downstream of the film hole. The effects of main stream turbulence conditions, boundary layer thickness, turbulence modeling, and numerical artificial dissipation are evaluated and found to have an insufficient impact in the wake region of separated films (i.e. cannot account for the discrepancy between measured and predicted centerline fluid temperatures). Analyses of low and moderate blowing ratio cases are carried out and results are in good agreement with data.
Thermo-tectonic history of Taranaki Basin (New Zealand) using Apatite Fission Track Analysis (AFTA)
Kamp, P.J.J.; Hegarty, K.A.; Green, P.F.
1988-01-01
The Taranaki basin, which extends offshore between the north and south island of New Zealand, contains several large gas fields (e.g., Maui field) and smaller oil fields. The Taranaki basin is New Zealand's only productive hydrocarbon basin. The basin trends north-south, is asymmetrical in cross section, and is faulted with up to 7 km of displacement along parts of its eastern margin. Preliminary results from Apatite Fission Track Analysis (AFTA) reveal the timing and magnitude of basin inversion. Four well cross sections from the southern part of the basin have been used. Initially, basin tectonics and sedimentation were associated with extension and the formation of half-grabens that began in the Late Cretaceous with the breakup of Gondwana. However, most of the observed subsidence and sedimentation resulted from mid-Cenozoic rifting throughout western New Zealand. Following the formation of the modern Australia-Pacific plate boundary during the early Miocene, the southern part of the basin, which lies 60 km from the Alpine fault in places, was partially inverted. AFTA parameters (apparent age and length) downhold at the Fresne-1 well show a distinct break in slope at 1,100 m depth (currently at 30/sup 0/C) where the apparent age is 15 Ma for the Late Cretaceous Parkawau Coal Measures. The data indicate that basin inversion began about 15 Ma and was accompanied by the removal of 2-3 km of section. Sedimentation began again in the Taranaki basin during the mid-Pliocene. The source of the gas and gas condensate in the basin is probably the Eocene coal measures. The maturation history of these beds and the overlying reservoirs was modeled using the constraints from AFTA data. Discrepancies exist between estimates of maximum paleotemperature from AFTA results and from vitrinite reflectance.
A GIS-based approach in drainage morphometric analysis of Kanhar River Basin, India
NASA Astrophysics Data System (ADS)
Rai, Praveen Kumar; Mohan, Kshitij; Mishra, Sameer; Ahmad, Aariz; Mishra, Varun Narayan
2014-11-01
The study indicates that analysis of morphometric parameters with the help of geographic information system (GIS) would prove a viable method of characterizing the hydrological response behaviour of the watershed. It is also well observed that remote sensing satellite data is emerging as the most effective, time saving and accurate technique for morphometric analysis of a basin. This technique is found relevant for the extraction of river basin and its stream networks through ASTER (DEM) in conjunction with remote sensing satellite data (Landsat etm+, 2013 and georeferenced survey of Indian toposheet, 1972). In this study, Kanhar basin a tributaries of Son River has been selected for detailed morphometric analysis. Seven sub-watersheds are also delineated within this basin to calculate the selected morphometric parameters. Morphometric parameters viz; stream order, stream length, bifurcation ratio, drainage density, stream frequency, form factor, circulatory ratio, etc., are calculated. The drainage area of the basin is 5,654 km2 and shows sub-dendritic to dendritic drainage pattern. The stream order of the basin is mainly controlled by physiographic and lithological conditions of the area. The study area is designated as seventh-order basin with the drainage density value being as 1.72 km/km2. The increase in stream length ratio from lower to higher order shows that the study area has reached a mature geomorphic stage.
Mas-Pla, Josep; Font, Eva; Astui, Oihane; Menció, Anna; Rodríguez-Florit, Agustí; Folch, Albert; Brusi, David; Pérez-Paricio, Alfredo
2012-12-01
Stream flow, as a part of a basin hydrological cycle, will be sensible to water scarcity as a result of climate change. Stream vulnerability should then be evaluated as a key component of the basin water budget. Numerical flow modeling has been applied to an alluvial formation in a small mountain basin to evaluate the stream-aquifer relationship under these future scenarios. The Arbúcies River basin (116 km(2)) is located in the Catalan Inner Basins (NE Spain) and its lower reach, which is related to an alluvial aquifer, usually becomes dry during the summer period. This study seeks to determine the origin of such discharge losses whether from natural stream leakage and/or induced capture due to groundwater withdrawal. Our goal is also investigating how discharge variations from the basin headwaters, representing potential effects of climate change, may affect stream flow, aquifer recharge, and finally environmental preservation and human supply. A numerical flow model of the alluvial aquifer, based on MODFLOW and especially in the STREAM routine, reproduced the flow system after the usual calibration. Results indicate that, in the average, stream flow provides more than 50% of the water inputs to the alluvial aquifer, being responsible for the amount of stored water resources and for satisfying groundwater exploitation for human needs. Detailed simulations using daily time-steps permit setting threshold values for the stream flow entering at the beginning of the studied area so surface discharge is maintained along the whole watercourse and ecological flow requirements are satisfied as well. The effects of predicted rainfall and temperature variations on the Arbúcies River alluvial aquifer water balance are also discussed from the outcomes of the simulations. Finally, model results indicate the relevance of headwater discharge management under future climate scenarios to preserve downstream hydrological processes. They also point out that small mountain basins
A Cartesian parametrization for the numerical analysis of material instability
Mota, Alejandro; Chen, Qiushi; Foulk, III, James W.; Ostien, Jakob T.; Lai, Zhengshou
2016-02-25
We examine four parametrizations of the unit sphere in the context of material stability analysis by means of the singularity of the acoustic tensor. We then propose a Cartesian parametrization for vectors that lie a cube of side length two and use these vectors in lieu of unit normals to test for the loss of the ellipticity condition. This parametrization is then used to construct a tensor akin to the acoustic tensor. It is shown that both of these tensors become singular at the same time and in the same planes in the presence of a material instability. Furthermore, themore » performance of the Cartesian parametrization is compared against the other parametrizations, with the results of these comparisons showing that in general, the Cartesian parametrization is more robust and more numerically efficient than the others.« less
Numerical Analysis for Structural Safety Evaluation of Butterfly Valves
NASA Astrophysics Data System (ADS)
Shin, Myung-Seob; Yoon, Joon-Yong; Park, Han-Yung
2010-06-01
Butterfly valves are widely used in current industry to control the fluid flow. They are used for both on-off and throttling applications involving large flows at relatively low operating pressure especially in large size pipelines. For the industrial application of butterfly valves, it must be ensured that the valve could be used safety under the fatigue life and the deformations produced by the pressure of the fluid. In this study, we carried out the structure analysis of the body and the valve disc of the butterfly valve and the numerical simulation was performed by using ANSYS v11.0. The reliability of valve is evaluated under the investigation of the deformation, the leak test and the durability of the valve.
Preliminary Numerical and Experimental Analysis of the Spallation Phenomenon
NASA Technical Reports Server (NTRS)
Martin, Alexandre; Bailey, Sean C. C.; Panerai, Francesco; Davuluri, Raghava S. C.; Vazsonyi, Alexander R.; Zhang, Huaibao; Lippay, Zachary S.; Mansour, Nagi N.; Inman, Jennifer A.; Bathel, Brett F.; Splinter, Scott C.; Danehy, Paul M.
2015-01-01
The spallation phenomenon was studied through numerical analysis using a coupled Lagrangian particle tracking code and a hypersonic aerothermodynamics computational fluid dynamics solver. The results show that carbon emission from spalled particles results in a significant modification of the gas composition of the post shock layer. Preliminary results from a test-campaign at the NASA Langley HYMETS facility are presented. Using an automated image processing of high-speed images, two-dimensional velocity vectors of the spalled particles were calculated. In a 30 second test at 100 W/cm2 of cold-wall heat-flux, more than 1300 particles were detected, with an average velocity of 102 m/s, and most frequent observed velocity of 60 m/s.
Numerical analysis of boosting scheme for scalable NMR quantum computation
SaiToh, Akira; Kitagawa, Masahiro
2005-02-01
Among initialization schemes for ensemble quantum computation beginning at thermal equilibrium, the scheme proposed by Schulman and Vazirani [in Proceedings of the 31st ACM Symposium on Theory of Computing (STOC'99) (ACM Press, New York, 1999), pp. 322-329] is known for the simple quantum circuit to redistribute the biases (polarizations) of qubits and small time complexity. However, our numerical simulation shows that the number of qubits initialized by the scheme is rather smaller than expected from the von Neumann entropy because of an increase in the sum of the binary entropies of individual qubits, which indicates a growth in the total classical correlation. This result--namely, that there is such a significant growth in the total binary entropy--disagrees with that of their analysis.
Numerical Analysis of a Finite Element/Volume Penalty Method
NASA Astrophysics Data System (ADS)
Maury, Bertrand
The penalty method makes it possible to incorporate a large class of constraints in general purpose Finite Element solvers like freeFEM++. We present here some contributions to the numerical analysis of this method. We propose an abstract framework for this approach, together with some general error estimates based on the discretization parameter ɛ and the space discretization parameter h. As this work is motivated by the possibility to handle constraints like rigid motion for fluid-particle flows, we shall pay a special attention to a model problem of this kind, where the constraint is prescribed over a subdomain. We show how the abstract estimate can be applied to this situation, in the case where a non-body-fitted mesh is used. In addition, we describe how this method provides an approximation of the Lagrange multiplier associated to the constraint.
Stability analysis and numerical simulation of simplified solid rocket motors
NASA Astrophysics Data System (ADS)
Boyer, G.; Casalis, G.; Estivalèzes, J.-L.
2013-08-01
This paper investigates the Parietal Vortex Shedding (PVS) instability that significantly influences the Pressure Oscillations of the long and segmented solid rocket motors. The eigenmodes resulting from the stability analysis of a simplified configuration, namely, a cylindrical duct with sidewall injection, are presented. They are computed taking into account the presence of a wall injection defect, which is shown to induce hydrodynamic instabilities at discrete frequencies. These instabilities exhibit eigenfunctions in good agreement with the measured PVS vortical structures. They are successfully compared in terms of temporal evolution and frequencies to the unsteady hydrodynamic fluctuations computed by numerical simulations. In addition, this study has shown that the hydrodynamic instabilities associated with the PVS are the driving force of the flow dynamics, since they are responsible for the emergence of pressure waves propagating at the same frequency.
Experimental and Numerical Analysis of Notched Composites Under Tension Loading
NASA Astrophysics Data System (ADS)
Aidi, Bilel; Case, Scott W.
2015-12-01
Experimental quasi-static tests were performed on center notched carbon fiber reinforced polymer (CFRP) composites having different stacking sequences made of G40-600/5245C prepreg. The three-dimensional Digital Image Correlation (DIC) technique was used during quasi-static tests conducted on quasi-isotropic notched samples to obtain the distribution of strains as a function of applied stress. A finite element model was built within Abaqus to predict the notched strength and the strain profiles for comparison with measured results. A user-material subroutine using the multi-continuum theory (MCT) as a failure initiation criterion and an energy-based damage evolution law as implemented by Autodesk Simulation Composite Analysis (ASCA) was used to conduct a quantitative comparison of strain components predicted by the analysis and obtained in the experiments. Good agreement between experimental data and numerical analyses results are observed. Modal analysis was carried out to investigate the effect of static damage on the dominant frequencies of the notched structure using the resulted degraded material elements. The first in-plane mode was found to be a good candidate for tracking the level of damage.
Structural and Kinematic Analysis of a Transpressional Basin in Central Anatolia: Çiçekdaǧ Basin
NASA Astrophysics Data System (ADS)
Tokay, Bülent; Lefebvre, Côme
2015-04-01
The Central Anatolian Crystalline Complex (CACC), which lies within Turkish Alpine orogenic belt, incorporates several basins located either within the complex or at and along its boundaries. Many of the basins developed during extension since Late Cretaceous and then evolved with advancing collision of Anatolide-Tauride with Pontides. With regard to deformation and evolution of the region, recent paleomagnetic study from the central Anatolian intrusives defines three blocks with characteristic rotation, pointing out the break-up of the CACC and the formation of two deformation zones between blocks. This study is focused on Çiçekdağ Basin (ÇB) which is located within one of the intensely deformed zones in the CACC. The structural analysis within and around ÇB in support of these models and claims is, however, limited. Thus this present study aims to provide more structural data that bears on the evolution of the Çiçekdağı Basin as well as the CACC, especially during regional contraction taking place at the end of the Eocene. Major structures of the study area fall into six groups: (i) E-W-trending synclines and a burried major reverse fault, suggesting N-S shortening; (ii) approximately NW-SE-trending plunging en-échelon folds, consistent with NE-SW compression; (iii) a NW-SE-trending (130°) left-lateral strike-slip fault; (iv) E-W-trending (260°) normal fault at southern edge of the basin and NW-SE-trending (~150°) normal fault; (v) NE-SW-trending reverse faults (~050°-055°) in the north of and middle of the basin, with hanging wall syncline geometry compatible with NW-SE to N-S compression; (vi) WNW- ESE trending reverse faults implying nearly N-S compression. At this stage, it is not clear to us if all these structures were encountered within the same strain field or they belong to a poly-phase deformation. This will be evaluated and discussed further.
Putnam, P.E.; Moore, S. ); Ward, G. )
1990-05-01
Linking hydrodynamics to detailed stratigraphic and structural analyses is a powerful tool in hydrocarbon exploration in mature basins, In southernmost Canada straddling the Alberta-Saskatchewan border, significant petroleum reserves are encountered within Mesozoic units which are largely controlled by subsurface flow cells. The Jurassic Sawtooth Formation is characterized by an eastward shift from lower shoreface quartzarenites to basinal coquinas. The Sawtooth is a blanket deposit and crops out along the flanks of several Tertiary uplifts in northern Montana. In the subsurface the Sawtooth is draped over several relatively young structures. Potentiometric mapping illustrates a northerly flow orientation within the Sawtooth, and oil pools under artesian conditions are located where flow paths cross steeply flanked structures. The Lower Cretaceous Sunburst Formation is a series of valley-fill sandstones with mainly southwesterly paleoflow orientations. Hydrocarbon pools (e.g., Manyberries field) are located within a regional potentiometric low formed by three converging cells which recharge in the south, northwest, and east. This potentiometric low is characterized by systematic changes in oil and water compositions, with progressively lighter oils and NaCl-rich waters found toward the low's center. Stratigraphic variability controls pooling within the low, with hydrocarbons located on the updip flanks of valley fills which border nonreservoir rocks. In the northwestern Williston basin regional hydrodynamic analysis, combined with standard subsurface approaches, allows operators to discern large new hydrocarbon-bearing trends within and between densely drilled areas characterized by complex structure and stratigraphy.
Effects of temperature on flood forecasting: analysis of an operative case study in Alpine basins
NASA Astrophysics Data System (ADS)
Ceppi, A.; Ravazzani, G.; Salandin, A.; Rabuffetti, D.; Montani, A.; Borgonovo, E.; Mancini, M.
2013-04-01
In recent years the interest in the forecast and prevention of natural hazards related to hydro-meteorological events has increased the challenge for numerical weather modelling, in particular for limited area models, to improve the quantitative precipitation forecasts (QPF) for hydrological purposes. After the encouraging results obtained in the MAP D-PHASE Project, we decided to devote further analyses to show recent improvements in the operational use of hydro-meteorological chains, and above all to better investigate the key role played by temperature during snowy precipitation. In this study we present a reanalysis simulation of one meteorological event, which occurred in November 2008 in the Piedmont Region. The attention is focused on the key role of air temperature, which is a crucial feature in determining the partitioning of precipitation in solid and liquid phase, influencing the quantitative discharge forecast (QDF) into the Alpine region. This is linked to the basin ipsographic curve and therefore by the total contributing area related to the snow line of the event. In order to assess hydrological predictions affected by meteorological forcing, a sensitivity analysis of the model output was carried out to evaluate different simulation scenarios, considering the forecast effects which can radically modify the discharge forecast. Results show how in real-time systems hydrological forecasters have to consider also the temperature uncertainty in forecasts in order to better understand the snow dynamics and its effect on runoff during a meteorological warning with a crucial snow line over the basin. The hydrological ensemble forecasts are based on the 16 members of the meteorological ensemble system COSMO-LEPS (developed by ARPA-SIMC) based on the non-hydrostatic model COSMO, while the hydrological model used to generate the runoff simulations is the rainfall-runoff distributed FEST-WB model, developed at Politecnico di Milano.
Buker, C.; Littke, R.; Welte, D.H.
1995-08-01
The detailed and reliable reconstruction of the geological and thermal evolution of sedimentary basins forms the indispensable basis of any simulation of generation, migration and accumulation of hydrocarbons. For this purpose - although often not taken into account - analysing and quantifying the uplift and erosion history is as important as the subsidence and temperature history. The reconstruction of the timing of hydrocarbon generation, petroleum expulsion and migration and the changing reservoir characteristics is only possible based on such an integrated approach. Applying this technique on the Carboniferous Ruhr Basin and the Lower Saxony Basin (western Germany) by utilising 1-D and 2-D forward modeling approaches resulted in important and new quantitative information on their temperature, subsidence and erosion histories which are of fundamental geological interest. The basin evolution models were calibrated using vitrinite reflectance data, fluid inclusion temperatures, and apatite and zircon fission track data. The detailed knowledge of the geological and thermal basin evolution then allowed in combination with a new kinetic model for gas generation from coals the modeling of generation, migration and accumulation of methane from Carboniferous coal seams.
Numerical analysis of sandstone composition, provenance, and paleogeography
Smosma, R.; Bruner, K.R.; Burns, A.
1999-09-01
Cretaceous deltaic sandstones of the National Petroleum Reserve in Alaska exhibit an extreme variability in their mineral makeup. A series of numerical techniques, however, provides some order to the petrographic characteristics of these complex rocks. Ten mineral constituents occur in the sandstones, including quartz, chert, feldspar, mica, and organic matter, plus rock fragments of volcanics, carbonates, shale, phyllite, and schist. A mixing coefficient quantities the degree of heterogeneity in each sample. Hierarchical cluster analysis then groups sandstones on the basis of similarities among all ten mineral components--in the Alaskan example, six groupings characterized mainly by the different rock fragments. Multidimensional scaling shows how the clusters relate to one another and arranges them along compositional gradients--two trends in Alaska based on varying proportions of metamorphic/volcanic and shale/carbonate rock fragments. The resulting sandstone clusters and petrographic gradients can be mapped across the study area and compared with the stratigraphic section. This study confirms the presence of three different source areas that provided diverse sediment to the Cretaceous deltas as well as the general transport directions and distances. In addition, the sand composition is shown to have changed over time, probably related to erosional unroofing in the source areas. This combination of multivariate-analysis techniques proves to be a powerful tool, revealing subtle spatial and temporal relationships among the sandstones and allowing one to enhance provenance and paleogeographic conclusions made from compositional data.
A hybrid neurocomputing/numerical strategy for nonlinear structural analysis
NASA Technical Reports Server (NTRS)
Szewczyk, Z. Peter; Noor, Ahmed K.
1995-01-01
A hybrid neurocomputing/numerical strategy is presented for geometrically nonlinear analysis of structures. The strategy combines model-free data processing capabilities of computational neural networks with a Pade approximants-based perturbation technique to predict partial information about the nonlinear response of structures. In the hybrid strategy, multilayer feedforward neural networks are used to extend the validity of solutions by using training samples produced by Pade approximations to the Taylor series expansion of the response function. The range of validity of the training samples is taken to be the radius of convergence of Pade approximants and is estimated by setting a tolerance on the diverging approximants. The norm of residual vector of unbalanced forces in a given element is used as a measure to assess the quality of network predictions. To further increase the accuracy and the range of network predictions, additional training data are generated by either applying linear regression to weight matrices or expanding the training data by using predicted coefficients in a Taylor series. The effectiveness of the hybrid strategy is assessed by performing large-deflection analysis of a doubly-curved composite panel with a circular cutout, and postbuckling analyses of stiffened composite panels subjected to an in-plane edge shear load. In all the problems considered, the hybrid strategy is used to predict selective information about the structural response, namely the total strain energy and the maximum displacement components only.
A stable and efficient numerical algorithm for unconfined aquifer analysis.
Keating, Elizabeth; Zyvoloski, George
2009-01-01
The nonlinearity of equations governing flow in unconfined aquifers poses challenges for numerical models, particularly in field-scale applications. Existing methods are often unstable, do not converge, or require extremely fine grids and small time steps. Standard modeling procedures such as automated model calibration and Monte Carlo uncertainty analysis typically require thousands of model runs. Stable and efficient model performance is essential to these analyses. We propose a new method that offers improvements in stability and efficiency and is relatively tolerant of coarse grids. It applies a strategy similar to that in the MODFLOW code to the solution of Richard's equation with a grid-dependent pressure/saturation relationship. The method imposes a contrast between horizontal and vertical permeability in gridblocks containing the water table, does not require "dry" cells to convert to inactive cells, and allows recharge to flow through relatively dry cells to the water table. We establish the accuracy of the method by comparison to an analytical solution for radial flow to a well in an unconfined aquifer with delayed yield. Using a suite of test problems, we demonstrate the efficiencies gained in speed and accuracy over two-phase simulations, and improved stability when compared to MODFLOW. The advantages for applications to transient unconfined aquifer analysis are clearly demonstrated by our examples. We also demonstrate applicability to mixed vadose zone/saturated zone applications, including transport, and find that the method shows great promise for these types of problem as well. PMID:19341374
A stable and efficient numerical algorithm for unconfined aquifer analysis
Keating, Elizabeth; Zyvoloski, George
2008-01-01
The non-linearity of equations governing flow in unconfined aquifers poses challenges for numerical models, particularly in field-scale applications. Existing methods are often unstable, do not converge, or require extremely fine grids and small time steps. Standard modeling procedures such as automated model calibration and Monte Carlo uncertainty analysis typically require thousands of forward model runs. Stable and efficient model performance is essential to these analyses. We propose a new method that offers improvements in stability and efficiency, and is relatively tolerant of coarse grids. It applies a strategy similar to that in the MODFLOW code to solution of Richard's Equation with a grid-dependent pressure/saturation relationship. The method imposes a contrast between horizontal and vertical permeability in gridblocks containing the water table. We establish the accuracy of the method by comparison to an analytical solution for radial flow to a well in an unconfined aquifer with delayed yield. Using a suite of test problems, we demonstrate the efficiencies gained in speed and accuracy over two-phase simulations, and improved stability when compared to MODFLOW. The advantages for applications to transient unconfined aquifer analysis are clearly demonstrated by our examples. We also demonstrate applicability to mixed vadose zone/saturated zone applications, including transport, and find that the method shows great promise for these types of problem, as well.
Analysis of sonic well logs applied to erosion estimates in the Bighorn Basin, Wyoming
Heasler, H.P.; Kharitonova, N.A.
1996-05-01
An improved exponential model of sonic transit time data as a function of depth takes into account the physical range of rock sonic velocities. In this way, the model is more geologically realistic for predicting compaction trends when compared to linear or simple exponential functions that fail at large depth intervals. The improved model is applied to the Bighorn basin of northwestern Wyoming for calculation of erosion amounts. This basin was chosen because of extensive geomorphic research that constrains erosion models and because of the importance of quantifying erosion amounts for basin analysis and hydrocarbon maturation prediction. Thirty-six wells were analyzed using the improved exponential model. Seven of these wells, due to limited data from the Tertiary section, were excluded from the basin erosion analysis. Erosion amounts from the remaining 29 wells ranged from 0 to 5600 ft (1700 m), with an average of 2500 ft (800 m).
NASA Astrophysics Data System (ADS)
Jones, Marvin Quenten, Jr.
The motion and behavior of quantum processes can be described by the Schrodinger equation using the wave function, Psi(x,t). The use of the Schrodinger equation to study quantum phenomena is known as Quantum Mechanics, akin to classical mechanics being the tool to study classical physics. This research focuses on the emphasis of numerical techniques: Finite-Difference, Fast Fourier Transform (spectral method), finite difference schemes such as the Leapfrog method and the Crank-Nicolson scheme and second quantization to solve and analyze the Schrodinger equation for the infinite square well problem, the free particle with periodic boundary conditions, the barrier problem, tight-binding hamiltonians and a potential wall problem. We discuss these techniques and the problems created to test how these different techniques draw both physical and numerical conclusions in a tabular summary. We observed both numerical stability and quantum stability (conservation of energy, probability, momentum, etc.). We found in our results that the Crank-Nicolson scheme is an unconditionally stable scheme and conserves probability (unitary), and momentum, though dissipative with energy. The time-independent problems conserved energy, momentum and were unitary, which is of interest, but we found when time-dependence was introduced, quantum stability (i.e. conservation of mass, momentum, etc.) was not implied by numerical stability. Hence, we observed schemes that were numerically stable, but not quantum stable as well as schemes that were quantum stable, but not numerically stable for all of time, t. We also observed that second quantization removed the issues with stability as the problem was transformed into a discrete problem. Moreover, all quantum information is conserved in second quantization. This method, however, does not work universally for all problems.
A LANDSCAPE ECOLOGY ANALYSIS OF THE GREAT LAKES BASIN
The U.S. Environmental Protection Agency (EPA) and Natural Resources Canada: Canada Centre for Remote Sensing (CCRS) are conducting a cooperative research landscape ecological study of the Great Lakes Basin. The analyses will include the areas located along the border of the Unit...
A REGIONAL ECOLOGICAL ANALYSIS OF THE GREAT LAKES BASIN
The U.S. Environmental Protection Agency (EPA) and Natural Resources Canada: Canada Centre for Remote Sensing (CCRS) are conducting a cooperative research landscape ecological study of the Great Lakes Basin. The analyses will include the areas located along the border of the Unit...
ALEXI analysis of water consumption in the Nile Basin
Technology Transfer Automated Retrieval System (TEKTRAN)
Remote sensing can be used to generate diagnostic estimates of evapotranspiration (ET) that provide information regarding consumptive water use across landscapes. These satellite-based assessments can be a valuable complement to prognostic simulations of basin-scale water budgets, providing an inde...
NASA Astrophysics Data System (ADS)
Fernández-Salas, Luis Miguel; Barcenas, Patricia; Macias, Jorge
2016-04-01
Numerical simulation of turbidity currents are used to study the formation of the seafloor undulations in the Adra prodeltaic system, western Mediterranean basin. A series of elongated and subparallel bathymetric undulations are distinguished in the foreset-bottomsets domain of the Holocene pro-deltaic wedge associated with the Adra river. In this study, multibeam data and surficial sediment samples have been used in comparison with numerical simulation to propose an evolutionary model of the seafloor undulations. Numerical model suggests that the depositional basin slope gradient is one of the factors more influent in the seafloor undulations formation. The simulations allowed to observe as seafloor undulations are approximately in phase with the undulations of the turbidity layer. Therefore, undulations are associated with Froude-supercritical flow. The upslope and downslope undulations boundaries are limited by a hydraulic jump where the flow makes a conversion from supercriticial flow (Fr>1) to subcritical flow (Fr<1), respectively. The undulations axis are characterized by a point where Fr=1. The subcritical zone generates net sediment deposition and the supercritical zone produces erosion. This explains why seafloor undulations migrate upslope. ACKNOWLEDGMENTS This research has been partially supported by the Junta de Andalucía research project TESELA (P11-RNM7069)
SAMSAN- MODERN NUMERICAL METHODS FOR CLASSICAL SAMPLED SYSTEM ANALYSIS
NASA Technical Reports Server (NTRS)
Frisch, H. P.
1994-01-01
SAMSAN was developed to aid the control system analyst by providing a self consistent set of computer algorithms that support large order control system design and evaluation studies, with an emphasis placed on sampled system analysis. Control system analysts have access to a vast array of published algorithms to solve an equally large spectrum of controls related computational problems. The analyst usually spends considerable time and effort bringing these published algorithms to an integrated operational status and often finds them less general than desired. SAMSAN reduces the burden on the analyst by providing a set of algorithms that have been well tested and documented, and that can be readily integrated for solving control system problems. Algorithm selection for SAMSAN has been biased toward numerical accuracy for large order systems with computational speed and portability being considered important but not paramount. In addition to containing relevant subroutines from EISPAK for eigen-analysis and from LINPAK for the solution of linear systems and related problems, SAMSAN contains the following not so generally available capabilities: 1) Reduction of a real non-symmetric matrix to block diagonal form via a real similarity transformation matrix which is well conditioned with respect to inversion, 2) Solution of the generalized eigenvalue problem with balancing and grading, 3) Computation of all zeros of the determinant of a matrix of polynomials, 4) Matrix exponentiation and the evaluation of integrals involving the matrix exponential, with option to first block diagonalize, 5) Root locus and frequency response for single variable transfer functions in the S, Z, and W domains, 6) Several methods of computing zeros for linear systems, and 7) The ability to generate documentation "on demand". All matrix operations in the SAMSAN algorithms assume non-symmetric matrices with real double precision elements. There is no fixed size limit on any matrix in any
Arnold, L.R.
2010-01-01
The Lost Creek Designated Ground Water Basin (Lost Creek basin) is an important alluvial aquifer for irrigation, public supply, and domestic water uses in northeastern Colorado. Beginning in 2005, the U.S. Geological Survey, in cooperation with the Lost Creek Ground Water Management District and the Colorado Water Conservation Board, collected hydrologic data and constructed a steady-state numerical groundwater flow model of the Lost Creek basin. The model builds upon the work of previous investigators to provide an updated tool for simulating the potential effects of various hydrologic stresses on groundwater flow and evaluating possible aquifer-management strategies. As part of model development, the thickness and extent of regolith sediments in the basin were mapped, and data were collected concerning aquifer recharge beneath native grassland, nonirrigated agricultural fields, irrigated agricultural fields, and ephemeral stream channels. The thickness and extent of regolith in the Lost Creek basin indicate the presence of a 2- to 7-mile-wide buried paleovalley that extends along the Lost Creek basin from south to north, where it joins the alluvial valley of the South Platte River valley. Regolith that fills the paleovalley is as much as about 190 ft thick. Average annual recharge from infiltration of precipitation on native grassland and nonirrigated agricultural fields was estimated by using the chloride mass-balance method to range from 0.1 to 0.6 inch, which represents about 1-4 percent of long-term average precipitation. Average annual recharge from infiltration of ephemeral streamflow was estimated by using apparent downward velocities of chloride peaks to range from 5.7 to 8.2 inches. Average annual recharge beneath irrigated agricultural fields was estimated by using passive-wick lysimeters and a water-balance approach to range from 0 to 11.3 inches, depending on irrigation method, soil type, crop type, and the net quantity of irrigation water applied
NASA Astrophysics Data System (ADS)
Schuller, V.; Frisch, W.
2003-12-01
The remnants of the Upper Cretaceous Gosau basins of the Apuseni Mts. record a similar sedimentary succession as the Gosau basins of the Eastern Alps: the Lower Gosau subgroup, represented by shallow marine sediments, and the Upper Gosau subgroup (turbiditic flysch and pelagic sediments). The controlling tectonic process of the Austroalpine Gosau basins is proposed to be subduction tectonic erosion, which led to the strong subsidence within these basins. Investigations on heavy minerals and the maturation of organic matter can help to understand the sudden subsidence which took place in Campanian/Maastrichtian time. The Lower Gosau subgroup reflects a predominantly metamorphic clastic source. In the Upper Gosau subgroup the metamorphic influence becomes less important. In some samples Chrome Spinel and Glaucophane has been identified. Both minerals in one assemblage show that a former accretional wedge with high-pressure rocks and obducted oceanic crust was eroded. The vitrinite reflectance data show a range of 0,8 to 1,8 % Rr within the Upper Cretaceous sequence. Increased coalification was measured close to large Banatitic and Neogene intrusions (up to 5.0 % Rr). For basin modeling, an erosion of 1600 m of Late Cretaceous sediments has been computed. Together with the measured and interpreted field data, the entire Gosau succession had a max. thickness of 2800 m. This thickness values are also reported from the Eastern Alps. Fission track dating was used to determine the age of the dedritic Zirkons. With this age-population-method a dynamic evolution of the hinterland concerning its exhumation and erosion can be modeled. Combined with models based on Apatit fission track length, a rapid uplift of the crystalline basement can be shown. All these results prove the similarity to the Gosau Basins of the Eastern Alps and the assumption that a direct connection to the Basins in the Apuseni Mts. existed during the Upper Cretaceous time. The main mechanism for the
Summary of research in applied mathematics, numerical analysis, and computer sciences
NASA Technical Reports Server (NTRS)
1986-01-01
The major categories of current ICASE research programs addressed include: numerical methods, with particular emphasis on the development and analysis of basic numerical algorithms; control and parameter identification problems, with emphasis on effective numerical methods; computational problems in engineering and physical sciences, particularly fluid dynamics, acoustics, and structural analysis; and computer systems and software, especially vector and parallel computers.
NASA Astrophysics Data System (ADS)
Nakayama, K.; Maruya, Y.; Matsumoto, K.; Komata, M.; Komai, K.; Kuwae, T.
2015-11-01
Total nitrogen (TN), which consists of total particulate nitrogen (TPN) and total dissolved nitrogen (TDN), is transported with not only in river channels but also across the entire river basin, including via ground water and migratory animals. In general, TPN export from an entire river basin to the ocean is larger than TDN in a mountainous region. Since marine derived nutrients (MDN) are hypothesized to be mainly transported as suspended matters from the ground surface, it is necessary to investigate the contribution of MDN to the forest floor (soils) in order to quantify the true role of MDN at the river ecosystem scale. This study investigated TN export from an entire river basin, and also we estimated the contribution of pink (Oncorhynchus gorbuscha) and chum salmon (O. keta) to total oceanic nitrogen input across a river basin. The maximum potential contribution of TN entering the river basin by salmon was found to be 23.8 % relative to the total amount of TN exported from the river basin. The contribution of particulate nitrogen based on suspended sediment from the ocean to the river basin soils was 22.9 % with SD of 3.6 % by using stable isotope analysis (SIA) of nitrogen (δ15N).
NASA Astrophysics Data System (ADS)
Zhurbas, V. M.; Oh, I. S.; Paka, V. T.
2003-01-01
A sigma ( σ)-coordinate ocean model by Blumberg and Mellor (POM) is applied to study the formation processes of mesoscale cyclones observed in the Eastern Gotland Basin following the dense water inflows. The initial conditions simulate a situation when the Arkona and Bornholm basins and partially the Slupsk Furrow are already filled with the inflow water of the North Sea origin, while the Eastern Gotland and Gdansk basins still contain the old water of pre-inflow stratification. Model runs with constant and time-dependent winds, changing the buoyancy forcing, grid geometry and bottom topography display the following. Entering the Eastern Gotland Basin from the Slupsk Furrow, the bottom intrusion of saline inflow water splits in two: one goes northeast towards the Gotland Deep, and second moves southeast towards the Gulf of Gdansk. An intensive mesoscale cyclonic eddy carrying the inflow water is generated just east of the Slupsk Furrow with the inflow pulse. A number of smaller cyclones with boluses of the inflow water are formed in the permanent halocline along the saline intrusion pathway to the Gotland Deep. Following Spall and Price [J. Phys. Oceanogr. 28 (1998) 1598], the cyclones are suggested to form by the adjustment of the high potential vorticity inflow water column to a low potential vorticity environment.
1-D Numerical Analysis of RBCC Engine Performance
NASA Technical Reports Server (NTRS)
Han, Samuel S.
1998-01-01
An RBCC engine combines air breathing and rocket engines into a single engine to increase the specific impulse over an entire flight trajectory. Considerable research pertaining to RBCC propulsion was performed during the 1960's and these engines were revisited recently as a candidate propulsion system for either a single-stage-to-orbit (SSTO) or two-stage-to-orbit (TSTO) launch vehicle. There are a variety of RBCC configurations that had been evaluated and new designs are currently under development. However, the basic configuration of all RBCC systems is built around the ejector scramjet engine originally developed for the hypersonic airplane. In this configuration, a rocket engine plays as an ejector in the air-augmented initial acceleration mode, as a fuel injector in scramjet mode and the rocket in all rocket mode for orbital insertion. Computational fluid dynamics (CFD) is a useful tool for the analysis of complex transport processes in various components in RBCC propulsion systems. The objective of the present research was to develop a transient 1-D numerical model that could be used to predict flow behavior throughout a generic RBCC engine following a flight path.
Numeric calculation of celestial bodies with spreadsheet analysis
NASA Astrophysics Data System (ADS)
Koch, Alexander
2016-04-01
The motion of the planets and moons in our solar system can easily be calculated for any time by the Kepler laws of planetary motion. The Kepler laws are a special case of the gravitational law of Newton, especially if you consider more than two celestial bodies. Therefore it is more basic to calculate the motion by using the gravitational law. But the problem is, that by gravitational law it is not possible to calculate the state of motion with only one step of calculation. The motion has to be numerical calculated for many time intervalls. For this reason, spreadsheet analysis is helpful for students. Skills in programmes like Excel, Calc or Gnumeric are important in professional life and can easily be learnt by students. These programmes can help to calculate the complex motions with many intervalls. The more intervalls are used, the more exact are the calculated orbits. The sutdents will first get a quick course in Excel. After that they calculate with instructions the 2-D-coordinates of the orbits of Moon and Mars. Step by step the students are coding the formulae for calculating physical parameters like coordinates, force, acceleration and velocity. The project is limited to 4 weeks or 8 lessons. So the calcualtion will only include the calculation of one body around the central mass like Earth or Sun. The three-body problem can only be shortly discussed at the end of the project.
Numerical Analysis of Heat Transfer During Quenching Process
NASA Astrophysics Data System (ADS)
Madireddi, Sowjanya; Krishnan, Krishnan Nambudiripad; Reddy, Ammana Satyanarayana
2016-06-01
A numerical model is developed to simulate the immersion quenching process of metals. The time of quench plays an important role if the process involves a defined step quenching schedule to obtain the desired characteristics. Lumped heat capacity analysis used for this purpose requires the value of heat transfer coefficient, whose evaluation requires large experimental data. Experimentation on a sample work piece may not represent the actual component which may vary in dimension. A Fluid-Structure interaction technique with a coupled interface between the solid (metal) and liquid (quenchant) is used for the simulations. Initial times of quenching shows boiling heat transfer phenomenon with high values of heat transfer coefficients (5000-2.5 × 105 W/m2K). Shape of the work piece with equal dimension shows less influence on the cooling rate Non-uniformity in hardness at the sharp corners can be reduced by rounding off the edges. For a square piece of 20 mm thickness, with 3 mm fillet radius, this difference is reduced by 73 %. The model can be used for any metal-quenchant combination to obtain time-temperature data without the necessity of experimentation.
Analysis of Numerical Simulation Results of LIPS-200 Lifetime Experiments
NASA Astrophysics Data System (ADS)
Chen, Juanjuan; Zhang, Tianping; Geng, Hai; Jia, Yanhui; Meng, Wei; Wu, Xianming; Sun, Anbang
2016-06-01
Accelerator grid structural and electron backstreaming failures are the most important factors affecting the ion thruster's lifetime. During the thruster's operation, Charge Exchange Xenon (CEX) ions are generated from collisions between plasma and neutral atoms. Those CEX ions grid's barrel and wall frequently, which cause the failures of the grid system. In order to validate whether the 20 cm Lanzhou Ion Propulsion System (LIPS-200) satisfies China's communication satellite platform's application requirement for North-South Station Keeping (NSSK), this study analyzed the measured depth of the pit/groove on the accelerator grid's wall and aperture diameter's variation and estimated the operating lifetime of the ion thruster. Different from the previous method, in this paper, the experimental results after the 5500 h of accumulated operation of the LIPS-200 ion thruster are presented firstly. Then, based on these results, theoretical analysis and numerical calculations were firstly performed to predict the on-orbit lifetime of LIPS-200. The results obtained were more accurate to calculate the reliability and analyze the failure modes of the ion thruster. The results indicated that the predicted lifetime of LIPS-200's was about 13218.1 h which could satisfy the required lifetime requirement of 11000 h very well.
Numerical Analysis of Orbital Perturbation Effects on Inclined Geosynchronous SAR.
Dong, Xichao; Hu, Cheng; Long, Teng; Li, Yuanhao
2016-01-01
The geosynchronous synthetic aperture radar (GEO SAR) is susceptible to orbit perturbations, leading to orbit drifts and variations. The influences behave very differently from those in low Earth orbit (LEO) SAR. In this paper, the impacts of perturbations on GEO SAR orbital elements are modelled based on the perturbed dynamic equations, and then, the focusing is analyzed theoretically and numerically by using the Systems Tool Kit (STK) software. The accurate GEO SAR slant range histories can be calculated according to the perturbed orbit positions in STK. The perturbed slant range errors are mainly the first and second derivatives, leading to image drifts and defocusing. Simulations of the point target imaging are performed to validate the aforementioned analysis. In the GEO SAR with an inclination of 53° and an argument of perigee of 90°, the Doppler parameters and the integration time are different and dependent on the geometry configurations. Thus, the influences are varying at different orbit positions: at the equator, the first-order phase errors should be mainly considered; at the perigee and apogee, the second-order phase errors should be mainly considered; at other positions, first-order and second-order exist simultaneously. PMID:27598168
a Numerical Method for Stability Analysis of Pinned Flexible Mechanisms
NASA Astrophysics Data System (ADS)
Beale, D. G.; Lee, S. W.
1996-05-01
A technique is presented to investigate the stability of mechanisms with pin-jointed flexible members. The method relies on a special floating frame from which elastic link co-ordinates are defined. Energies are easily developed for use in a Lagrange equation formulation, leading to a set of non-linear and mixed ordinary differential-algebraic equations of motion with constraints. Stability and bifurcation analysis is handled using a numerical procedure (generalized co-ordinate partitioning) that avoids the tedious and difficult task of analytically reducing the system of equations to a number equalling the system degrees of freedom. The proposed method was then applied to (1) a slider-crank mechanism with a flexible connecting rod and crank of constant rotational speed, and (2) a four-bar linkage with a flexible coupler with a constant speed crank. In both cases, a single pinned-pinned beam bending mode is employed to develop resonance curves and stability boundaries in the crank length-crank speed parameter plane. Flip and fold bifurcations are common occurrences in both mechanisms. The accuracy of the proposed method was also verified by comparison with previous experimental results [1].
Numerical Simulation and Scaling Analysis of Cell Printing
NASA Astrophysics Data System (ADS)
Qiao, Rui; He, Ping
2011-11-01
Cell printing, i.e., printing three dimensional (3D) structures of cells held in a tissue matrix, is gaining significant attention in the biomedical community. The key idea is to use inkjet printer or similar devices to print cells into 3D patterns with a resolution comparable to the size of mammalian cells. Achieving such a resolution in vitro can lead to breakthroughs in areas such as organ transplantation. Although the feasibility of cell printing has been demonstrated recently, the printing resolution and cell viability remain to be improved. Here we investigate a unit operation in cell printing, namely, the impact of a cell-laden droplet into a pool of highly viscous liquids. The droplet and cell dynamics are quantified using both direct numerical simulation and scaling analysis. These studies indicate that although cell experienced significant stress during droplet impact, the duration of such stress is very short, which helps explain why many cells can survive the cell printing process. These studies also revealed that cell membrane can be temporarily ruptured during cell printing, which is supported by indirect experimental evidence.
Wilkins, D.W.; Scott, W.B.; Kaehler, C.A.
1980-01-01
The study of the Southwest alluvial basins (east) will involve an analysis of the regional aquifer system in parts of Colorado, New Mexico, and Texas. This area has been divided into 22 basins. The study of the alluvial aquifer-system will be made in the following stages: (1) project planning, (2) literature searches, (3) compiling existing data, (4) data collection, (5) basin modeling, (6) regional aquifer modeling, and (7) reports. The regional aquifer study will be accomplished through studying each of the 22 basins. Data compilation and limited data collection will be part of each basin study. Digital computer models will be made for those basins where data are sufficient. A regional aquifer model will be developed from the basin models. In addition to this report, there will be basin hydrology reports and the final regional report. Included in the final report will be a description of the regional hydrology and geology. (USGS)
Numerical analysis of seismoelectromagnetic field conversion at confined geological units
NASA Astrophysics Data System (ADS)
Kroeger, B.; Kemna, A.
2010-12-01
It is well known that at material boundaries in fluid-saturated porous media, an incoming seismic wave can give rise to electric and magnetic fields due to electrokinetic coupling effects. Given its sensitivity to rock parameters governing fluid flow, this so-called seismoelectromagnetic (or seismoelectric, if only the electric field is considered) interface response is of strong interest with a view to hydro geophysical and petroleum exploration applications. However, the understanding of the correspondence of the converting interface geometry on the one hand and electric and magnetic field characteristics on the other hand is still poor. By means of two-dimensional finite-element modeling in the time domain, we here investigate the character of the seismoelectromagnetic interface response for the special case of spatially confined geological units, which may be representative for clay lenses embedded in an aquifer or petroleum deposits in a host rock. In the numerical analysis we consider the interface response generated by both compressional and shear wave. The modeling results, which are analyzed in terms of snapshots, time slices, and electro and magneto grams, reveal a significant influence of the confined geological units on the generation and character of the seismoelectro-magnetic interface response. The different conversion patterns can be attributed to the induced streaming currents at the interfaces caused by the oscillation of the seismic body waves. Pattern analysis of the interface responses is done with a view to an improved qualitative understanding of their spatio-temporal occurrence and evolution relative to the geometry of the converting interfaces. Our time-lapse simulations illustrate that the seismoelectromagnetic interface response captures characteristics of the geometry of the converting geological unit, indicating the potential of the seismoelectromagnetic method in particular for exploration of confined targets.
Numerical analysis of flow through oscillating cascade sections
NASA Technical Reports Server (NTRS)
Huff, Dennis L.
1989-01-01
The design of turbomachinery blades requires the prevention of flutter for all operating conditions. However, flow field predictions used for aeroelastic analysis are not well understood for all flow regimes. The present research focuses on numerical solutions of the Euler and Navier-Stokes equations using an ADI procedure to model two-dimensional, transonic flow through oscillating cascades. The model prescribes harmonic pitching motions for the blade sections for both zero and non-zero inter-blade phase angles. The code introduces the use of a deforming grid technique for convenient specification of the periodic boundary conditions. Approximate nonreflecting boundary conditions have been coded for the inlet and exit boundary conditions. Sample unsteady solutions have been performed for an oscillating cascade and compared to experimental data. Also, test cases were fun for a flat plate cascade to compare with an unsteady, small-perturbation, subsonic analysis. The predictions for oscillating cascades with non-zero inter-blade phase angles are in good agreement with experimental data and small-perturbation theory. The zero degree inter-blade phase angle cases, which were near a resonant condition, differ from the experiment and theory. Studies on reflecting versus non-reflecting inlet and exit boundary conditions show that the treatment of the boundary can have a significant effect on the first harmonic, unsteady pressure distributions for certain flow conditions. This code is expected to be used as a tool for reviewing simpler models that do not include the full nonlinear aerodynamics or as a final check for designs against flutter in turbomachinery.
Analysis of the Tanana River Basin using LANDSAT data
NASA Technical Reports Server (NTRS)
Morrissey, L. A.; Ambrosia, V. G.; Carson-Henry, C.
1981-01-01
Digital image classification techniques were used to classify land cover/resource information in the Tanana River Basin of Alaska. Portions of four scenes of LANDSAT digital data were analyzed using computer systems at Ames Research Center in an unsupervised approach to derive cluster statistics. The spectral classes were identified using the IDIMS display and color infrared photography. Classification errors were corrected using stratification procedures. The classification scheme resulted in the following eleven categories; sedimented/shallow water, clear/deep water, coniferous forest, mixed forest, deciduous forest, shrub and grass, bog, alpine tundra, barrens, snow and ice, and cultural features. Color coded maps and acreage summaries of the major land cover categories were generated for selected USGS quadrangles (1:250,000) which lie within the drainage basin. The project was completed within six months.
NASA Astrophysics Data System (ADS)
Cazzani, Antonio; Malagù, Marcello; Turco, Emilio
2016-03-01
We illustrate a numerical tool for analyzing plane arches such as those frequently used in historical masonry heritage. It is based on a refined elastic mechanical model derived from the isogeometric approach. In particular, geometry and displacements are modeled by means of non-uniform rational B-splines. After a brief introduction, outlining the basic assumptions of this approach and the corresponding modeling choices, several numerical applications to arches, which are typical of masonry structures, show the performance of this novel technique. These are discussed in detail to emphasize the advantage and potential developments of isogeometric analysis in the field of structural analysis of historical masonry buildings with complex geometries.
Great Basin NV Play Fairway Analysis - Carson Sink
Jim Faulds
2015-10-28
All datasets and products specific to the Carson Sink basin. Includes a packed ArcMap (.mpk), individually zipped shapefiles, and a file geodatabase for the Carson Sink area; a GeoSoft Oasis montaj project containing GM-SYS 2D gravity profiles along the trace of our seismic reflection lines; a 3D model in EarthVision; spreadsheet of links to published maps; and spreadsheets of well data.
NASA Astrophysics Data System (ADS)
Chaljub, Emmanuel; Maufroy, Emeline; Moczo, Peter; Kristek, Jozef; Priolo, Enrico; Klin, Peter; De Martin, Florent; Zhang, Zenghuo; Hollender, Fabrice; Bard, Pierre-Yves
2013-04-01
Numerical simulation is playing a role of increasing importance in the field of seismic hazard by providing quantitative estimates of earthquake ground motion, its variability, and its sensitivity to geometrical and mechanical properties of the medium. Continuous efforts to develop accurate and computationally efficient numerical methods, combined with increasing computational power have made it technically feasible to calculate seismograms in 3D realistic configurations and for frequencies of interest in seismic design applications. Now, in order to foster the use of numerical simulations in practical prediction of earthquake ground motion, it is important to evaluate the accuracy of current numerical methods when applied to realistic 3D sites. This process of verification is a necessary prerequisite to confrontation of numerical predictions and observations. Through the ongoing Euroseistest Verification and Validation Project (E2VP), which focuses on the Mygdonian basin (northern Greece), we investigated the capability of numerical methods to predict earthquake ground motion for frequencies up to 4 Hz. Numerical predictions obtained by several teams using a wide variety of methods were compared using quantitative goodness-of-fit criteria. In order to better understand the cause of misfits between different simulations, initially performed for the realistic geometry of the Mygdonian basin, we defined five stringent canonical configurations. The canonical models allow for identifying sources of misfits and quantify their importance. Detailed quantitative comparison of simulations in relation to dominant features of the models shows that even relatively simple heterogeneous models must be treated with maximum care in order to achieve sufficient level of accuracy. One important conclusion is that the numerical representation of models with strong variations (e.g. discontinuities) may considerably vary from one method to the other, and may become a dominant source of
Voronin, Lois M.; Densmore, Jill N.; Martin, Peter; Brush, Charles F.; Carlson, Carl S.; Miller, David M.
2013-01-01
Groundwater withdrawals began in 1992 from the Langford Basin within the Fort Irwin National Training Center (NTC), California. From April 1992 to December 2010, approximately 12,300 acre-feet of water (averaging about 650 acre-feet per year) has been withdrawn from the basin and transported to the adjacent Irwin Basin. Since withdrawals began, water levels in the basin have declined by as much as 40 feet, and the quality of the groundwater withdrawn from the basin has deteriorated. The U.S. Geological Survey collected geohydrologic data from Langford Basin during 1992–2011 to determine the quantity and quality of groundwater available in the basin. Geophysical surveys, including gravity, seismic refraction, and time-domain electromagnetic induction surveys, were conducted to determine the depth and shape of the basin, to delineate depths to the Quaternary-Tertiary interface, and to map the depth to the water table and changes in water quality. Data were collected from existing wells and test holes, as well as 11 monitor wells that were installed at 5 sites as part of this study. Water-quality samples collected from wells in the basin were used to determine the groundwater chemistry within the basin and to delineate potential sources of poor-quality groundwater. Analysis of stable isotopes of oxygen and hydrogen in groundwater indicates that present-day precipitation is not a major source of recharge to the basin. Tritium and carbon-14 data indicate that most of the basin was recharged prior to 1952, and the groundwater in the basin has an apparent age of 12,500 to 30,000 years. Recharge to the basin, estimated to be less than 50 acre-feet per year, has not been sufficient to replenish the water that is being withdrawn from the basin. A numerical groundwater-flow model was developed for the Langford Basin to better understand the aquifer system used by the Fort Irwin NTC as part of its water supply, and to provide a tool to help manage groundwater resources at
NASA Astrophysics Data System (ADS)
Hanson, Andrew Dean
Organic geochemistry of oils from the Tarim basin, NW China, distinguish at least seven genetic groups of oils. The largest group are derived from Middle-Upper Ordovician anoxic slope-facies marls coincident with the margins of structural uplifts. Other groups include non-marine derived oils in the Luntai uplift, from southwest Tarim, in the Kuqa depression, and west of the Bachu uplift. A seep sample from west of Kashi clusters with Luntai oils. These results suggest that numerous source-rock horizons occur, but they are really restricted. Organic geochemistry of oils from northern Qaidam defines a family of hypersaline, anoxic lacustrine derived oils. Cenozoic outcrop samples from northern Qaidam are too organic lean to be of source quality, but dark laminated upper Oligocene mudstones from the Shi 28 well are of fair to good quality. Biomarkers provide a good correlation between the oils and the core samples. Organic matter is from algae and bacteria and lacks terrestrial material. Hydrocarbons are contained in upper Oligocene, Miocene, and Pliocene reservoirs. Eight oils are from NW Qaidam, but one sample comes from NE Qaidam, an area previously believed to only produce oils derived from Jurassic source rocks. Thus an unidentified Cenozoic source rock occurs in NE Qaidam. Thermal modeling indicates generation occurred in northwestern Qaidam within the last 3 million years, agreeing with observed low maturity biomarker parameters. Cenozoic stratigraphy in northern Qaidam and southern Tarim basins record the tectonic history of the surrounding structural/topographic elements. Paleocurrents record flow away from adjacent ranges from the Miocene to the present. Provenance data tie sediments to adjacent structural elements. Petrography indicates increasingly immature sandstones in Miocene and younger sediments relative to pre-Miocene samples. Apatite fission-track results from southeastern Tarim yield a cooling age of 17 +/- 1 Ma indicative of unroofing since at
Ernest Mancini
2000-12-31
Part 3 (Petroleum System Modeling of the Jurassic Smackover Formation) objectives are to provide an analysis of the Smackover petroleum system in Years 4 and 5 of the project and to transfer effectively the research results to producers through workshops and topical reports. Work Accomplished (Year 5): Task 1 - Basin Flow - Basin flow modeling has been completed and the modeling results are being interpreted for report writing (Table 1). Task 2 - Petroleum Source Rocks - Work on the characterization of Smackover petroleum source rocks has been integrated into the basin flow model. Task 3 - Petroleum Reservoirs - Work on the characterization of Smackover petroleum reservoirs continues. The cores to be described have been identified and many of the cores for the eastern part of the basin have been described. Task 4 - Reservoir Diagenesis - Work on reservoir diagenesis has been initiated. Samples from the cores selected for the reservoir characterization are being used for this task. Work Planned (Year 5): Task 1 - Basin Flow - The report on basin flow will be completed. Task 2 - Petroleum Source Rocks - Petroleum source rock data will be reviewed in light of the basin flow model results. Task 3 - Petroleum Reservoirs - Characterization of petroleum reservoirs will continue through core studies. Task 4 - Reservoir Diagenesis - Characterization of reservoir diagenesis will continue through petrographic analysis.
Ernest A. Mancini; Donald A. Goddard
2005-08-01
The principal research effort for Year 3 of the project is basin modeling and petroleum system identification, comparative basin evaluation and resource assessment. In the first six (6) months of Year 3, the research focus is on basin modeling and petroleum system identification and the remainder of the year the emphasis is on the comparative basin evaluation and resource assessment. No major problems have been encountered to date, and the project is on schedule.
NASA Astrophysics Data System (ADS)
Hedrick, A. R.; Marks, D. G.; Winstral, A. H.; Marshall, H. P.
2014-12-01
The ability to forecast snow water equivalent, or SWE, in mountain catchments would benefit many different communities ranging from avalanche hazard mitigation to water resource management. Historical model runs of Isnobal, the physically based energy balance snow model, have been produced over the 2150 km2 Boise River Basin for water years 2012 - 2014 at 100-meter resolution. Spatially distributed forcing parameters such as precipitation, wind, and relative humidity are generated from automated weather stations located throughout the watershed, and are supplied to Isnobal at hourly timesteps. Similarly, the Weather Research & Forecasting (WRF) Model provides hourly predictions of the same forcing parameters from an atmospheric physics perspective. This work aims to quantitatively compare WRF model output to the spatial meteorologic fields developed to force Isnobal, with the hopes of eventually using WRF predictions to create accurate hourly forecasts of SWE over a large mountainous basin.
Investigation of Biogrout processes by numerical analysis at pore scale
NASA Astrophysics Data System (ADS)
Bergwerff, Luke; van Paassen, Leon A.; Picioreanu, Cristian; van Loosdrecht, Mark C. M.
2013-04-01
Biogrout is a soil improving process that aims to improve the strength of sandy soils. The process is based on microbially induced calcite precipitation (MICP). In this study the main process is based on denitrification facilitated by bacteria indigenous to the soil using substrates, which can be derived from pretreated waste streams containing calcium salts of fatty acids and calcium nitrate, making it a cost effective and environmentally friendly process. The goal of this research is to improve the understanding of the process by numerical analysis so that it may be improved and applied properly for varying applications, such as borehole stabilization, liquefaction prevention, levee fortification and mitigation of beach erosion. During the denitrification process there are many phases present in the pore space including a liquid phase containing solutes, crystals, bacteria forming biofilms and gas bubbles. Due to the amount of phases and their dynamic changes (multiphase flow with (non-linear) reactive transport), there are many interactions making the process very complex. To understand this complexity in the system, the interactions between these phases are studied in a reductionist approach, increasing the complexity of the system by one phase at a time. The model will initially include flow, solute transport, crystal nucleation and growth in 2D at pore scale. The flow will be described by Navier-Stokes equations. Initial study and simulations has revealed that describing crystal growth for this application on a fixed grid can introduce significant fundamental errors. Therefore a level set method will be employed to better describe the interface of developing crystals in between sand grains. Afterwards the model will be expanded to 3D to provide more realistic flow, nucleation and clogging behaviour at pore scale. Next biofilms and lastly gas bubbles may be added to the model. From the results of these pore scale models the behaviour of the system may be
Numerical analysis of fume formation mechanism in arc welding
NASA Astrophysics Data System (ADS)
Tashiro, Shinichi; Zeniya, Tasuku; Yamamoto, Kentaro; Tanaka, Manabu; Nakata, Kazuhiro; Murphy, Anthony B.; Yamamoto, Eri; Yamazaki, Kei; Suzuki, Keiichi
2010-11-01
In order to clarify the fume formation mechanism in arc welding, a quantitative investigation based on the knowledge of interaction among the electrode, arc and weld pool is indispensable. A fume formation model consisting of a heterogeneous condensation model, a homogeneous nucleation model and a coagulation model has been developed and coupled with the GTA or GMA welding model. A series of processes from evaporation of metal vapour to fume formation from the metal vapour was totally investigated by employing this simulation model. The aim of this paper is to visualize the fume formation process and clarify the fume formation mechanism theoretically through a numerical analysis. Furthermore, the reliability of the simulation model was also evaluated through a comparison of the simulation result with the experimental result. As a result, it was found that the size of the secondary particles consisting of small particles with a size of several tens of nanometres reached 300 nm at maximum and the secondary particle was in a U-shaped chain form in helium GTA welding. Furthermore, it was also clarified that most part of the fume was produced in the downstream region of the arc originating from the metal vapour evaporated mainly from the droplet in argon GMA welding. The fume was constituted by particles with a size of several tens of nanometres and had similar characteristics to that of GTA welding. On the other hand, if the metal transfer becomes unstable and the metal vapour near the droplet diffuses directly towards the surroundings of the arc not getting into the plasma flow, the size of the particles reaches several hundred nanometres.
Numerical Analysis of the Sea State Bias for Satellite Altimetry
NASA Technical Reports Server (NTRS)
Glazman, R. E.; Fabrikant, A.; Srokosz, M. A.
1996-01-01
Theoretical understanding of the dependence of sea state bias (SSB) on wind wave conditions has been achieved only for the case of a unidirectional wind-driven sea. Recent analysis of Geosat and TOPEX altimeter data showed that additional factors, such as swell, ocean currents, and complex directional properties of realistic wave fields, may influence SSB behavior. Here we investigate effects of two-dimensional multimodal wave spectra using a numerical model of radar reflection from a random, non-Gaussian surface. A recently proposed ocean wave spectrum is employed to describe sea surface statistics. The following findings appear to be of particular interest: (1) Sea swell has an appreciable effect in reducing the SSB coefficient compared with the pure wind sea case but has less effect on the actual SSB owing to the corresponding increase in significant wave height. (2) Hidden multimodal structure (the two-dimensional wavenumber spectrum contains separate peaks, for swell and wind seas, while the frequency spectrum looks unimodal) results in an appreciable change of SSB. (3) For unimodal, purely wind-driven seas, the influence of the angular spectral width is relatively unimportant; that is, a unidirectional sea provides a good qualitative model for SSB if the swell is absent. (4) The pseudo wave age is generally much better fo parametrization the SSB coefficient than the actual wave age (which is ill-defined for a multimodal sea) or wind speed. (5) SSB can be as high as 5% of the significant wave height, which is significantly greater than predicted by present empirical model functions tuned on global data sets. (6) Parameterization of SSB in terms of wind speed is likely to lead to errors due to the dependence on the (in practice, unknown) fetch.
NASA Astrophysics Data System (ADS)
Anka, Zahie; Ondrak, Robert; Kowitz, Astrid; Schødt, Niels
2013-09-01
We present a combined approach of interpretation of 2D seismic-reflection data and numerical modelling of hydrocarbon generation and migration across the southern slope of the Lower Congo Basin, in order to investigate the factors controlling timing and distribution of hydrocarbon leakage in this area. We identified three main families of past and present-day leakage features: (1) Mid-Upper Miocene seismic chimneys concentrated basinwards and ending up on buried pockmarks, (2) Plio-Pleistocene chimneys, rather clustered to the east of the study area and ending up in seafloor pockmarks, and (3) fewer scattered chimneys identified within the Miocene sequences ending up in shallow enhanced reflectors ("Flat spots"). Stratigraphic and structural elements seem to control the distribution of these features. At least two major events of leakage occurred during the Middle-Late Miocene and intermittently during the Pliocene-Present. External factors as sediment supply are associated to the Miocene leakage event, whilst internal structural elements probably triggered the Pliocene to present-day leakage. A major seabed morphological feature, represented by a margin-paralleled belt of more than 1-km-wide mounds, was identified above growth faults to the east of the study area. Data-constrained 2D HC generation and migration modelling suggests a genetic link between these structures and vertical migration/leakage of thermogenic methane sourced from either currently mature Oligo-Miocene source rocks or secondary cracking and further expulsion from over-mature Upper-Cretaceous source rocks. Hence, the mounds are likely to represent a lineation of methane-derived carbonate build-ups. Despite the natural limitations of a 2D migration model, when combined and calibrated with observations from seismic data, it can be used as a valid tool to assess petroleum migration routes in sedimentary basins. To the best of our knowledge, this is the first integrated approach combining both
NASA Astrophysics Data System (ADS)
Mohanty, S.; Jha, Madan K.; Kumar, Ashwani; Panda, D. K.
2013-07-01
In view of worldwide concern for the sustainability of groundwater resources, basin-wide modeling of groundwater flow is essential for the efficient planning and management of groundwater resources in a groundwater basin. The objective of the present study is to evaluate the performance of finite difference-based numerical model MODFLOW and the artificial neural network (ANN) model developed in this study in simulating groundwater levels in an alluvial aquifer system. Calibration of the MODFLOW was done by using weekly groundwater level data of 2 years and 4 months (February 2004 to May 2006) and validation of the model was done using 1 year of groundwater level data (June 2006 to May 2007). Calibration of the model was performed by a combination of trial-and-error method and automated calibration code PEST with a mean RMSE (root mean squared error) value of 0.62 m and a mean NSE (Nash-Sutcliffe efficiency) value of 0.915. Groundwater levels at 18 observation wells were simulated for the validation period. Moreover, artificial neural network models were developed to predict groundwater levels in 18 observation wells in the basin one time step (i.e., week) ahead. The inputs to the ANN model consisted of weekly rainfall, evaporation, river stage, water level in the drain, pumping rate of the tubewells and groundwater levels in these wells at the previous time step. The time periods used in the MODFLOW were also considered for the training and testing of the developed ANN models. Out of the 174 data sets, 122 data sets were used for training and 52 data sets were used for testing. The simulated groundwater levels by MODFLOW and ANN model were compared with the observed groundwater levels. It was found that the ANN model provided better prediction of groundwater levels in the study area than the numerical model for short time-horizon predictions.
Sheet Hydroforming Process Numerical Model Improvement Through Experimental Results Analysis
NASA Astrophysics Data System (ADS)
Gabriele, Papadia; Antonio, Del Prete; Alfredo, Anglani
2010-06-01
The increasing application of numerical simulation in metal forming field has helped engineers to solve problems one after another to manufacture a qualified formed product reducing the required time [1]. Accurate simulation results are fundamental for the tooling and the product designs. The wide application of numerical simulation is encouraging the development of highly accurate simulation procedures to meet industrial requirements. Many factors can influence the final simulation results and many studies have been carried out about materials [2], yield criteria [3] and plastic deformation [4,5], process parameters [6] and their optimization. In order to develop a reliable hydromechanical deep drawing (HDD) numerical model the authors have been worked out specific activities based on the evaluation of the effective stiffness of the blankholder structure [7]. In this paper after an appropriate tuning phase of the blankholder force distribution, the experimental activity has been taken into account to improve the accuracy of the numerical model. In the first phase, the effective capability of the blankholder structure to transfer the applied load given by hydraulic actuators to the blank has been explored. This phase ended with the definition of an appropriate subdivision of the blankholder active surface in order to take into account the effective pressure map obtained for the given loads configuration. In the second phase the numerical results obtained with the developed subdivision have been compared with the experimental data of the studied model. The numerical model has been then improved, finding the best solution for the blankholder force distribution.
Tularosa Basin Play Fairway Analysis: Hydrothermal Alteration Map
Adam Brandt
2015-11-15
This is a hydrothermal alteration map of the Tularosa Basin area, New Mexico and Texas that was created using Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) multispectral data band ratios based upon diagnostic features of clay, calcite, silica, gypsum, ferric iron, and ferrous iron. Mesoproterozoic granite in the San Andreas Range often appeared altered, but this may be from clays produced by weathering or, locally, by hydrothermal alteration. However, no field checking was done. This work was done under U.S. D.O.E. Contract #DE-EE0006730
NASA Astrophysics Data System (ADS)
Nakayama, K.; Maruya, Y.; Matsumoto, K.; Komata, M.; Komai, K.; Kuwae, T.
2015-04-01
Since marine derived nutrients (MDN) are transported not only in river channels but also across the entire river basin, including via ground water and migratory animals, it is necessary to investigate the contribution of MDN to the forest floor (soils) in order to quantify the true role of MDN at the river ecosystem scale. This study investigated the contribution of pink (Oncorhynchus gorbuscha) and chum salmon (O. keta) to total oceanic nitrogen (TN) input across a river basin using stable isotope analysis (SIA) of nitrogen (δ15N). The contribution of TN entering the river basin by salmon was 23.8 % relative to the total amount of TN exported from the river basin, providing a first estimate of MDN export for a river basin. The contribution of nitrogen from the ocean to the river basin soils was between 22.9 and 23.8 %. Furthermore, SIA showed that the transport of oceanic TN by sea eagles (Haliaeetus spp.) was greater than that by bears (Ursus arctos), which had previously been that bears are thought to be the major animal transporter of nutrients in the northern part of Japan.
Quantitative analysis of numerical solvers for oscillatory biomolecular system models
Quo, Chang F; Wang, May D
2008-01-01
Background This article provides guidelines for selecting optimal numerical solvers for biomolecular system models. Because various parameters of the same system could have drastically different ranges from 10-15 to 1010, the ODEs can be stiff and ill-conditioned, resulting in non-unique, non-existing, or non-reproducible modeling solutions. Previous studies have not examined in depth how to best select numerical solvers for biomolecular system models, which makes it difficult to experimentally validate the modeling results. To address this problem, we have chosen one of the well-known stiff initial value problems with limit cycle behavior as a test-bed system model. Solving this model, we have illustrated that different answers may result from different numerical solvers. We use MATLAB numerical solvers because they are optimized and widely used by the modeling community. We have also conducted a systematic study of numerical solver performances by using qualitative and quantitative measures such as convergence, accuracy, and computational cost (i.e. in terms of function evaluation, partial derivative, LU decomposition, and "take-off" points). The results show that the modeling solutions can be drastically different using different numerical solvers. Thus, it is important to intelligently select numerical solvers when solving biomolecular system models. Results The classic Belousov-Zhabotinskii (BZ) reaction is described by the Oregonator model and is used as a case study. We report two guidelines in selecting optimal numerical solver(s) for stiff, complex oscillatory systems: (i) for problems with unknown parameters, ode45 is the optimal choice regardless of the relative error tolerance; (ii) for known stiff problems, both ode113 and ode15s are good choices under strict relative tolerance conditions. Conclusions For any given biomolecular model, by building a library of numerical solvers with quantitative performance assessment metric, we show that it is possible
Tectonic Subsidence Analysis of the Pearl River Mouth Basin, Northern South China Sea
NASA Astrophysics Data System (ADS)
Tang, X.; Huang, S. S. X. E. C.; Zhuang, W.; LIU, Z.; Duan, W.; Hu, S.
2015-12-01
The Pearl River Mouth Basin (PRMB hereafter) in the northern margin of the South China Sea has attracted great attention not only because of its special tectonic location but also for its abundant hydrocarbon resources. Tectonic evolution controls the petroleum geological condition of hydrocarbon-bearing basins. Efforts have been made to understand the tectonic evolution of this basin. However, many issues about the tectonic features and the evolution process of this basin, such as the age of the breakup unconformities and the anomalously accelerated subsidence during the post-rifting stage, remain controversial. Here we employ tectonic subsidence analysis of sedimentary basins, a technique of removing isostatic loading and compaction effects by back-stripping, to investigate the tectonic controls on the basin formation of the PRMB. We performed the analysis on 4 drill wells and 43 synthetic wells constructed based on recently acquired seismic profiles. The result shows that tectonic subsidence in the eastern sags of the PRMB began to decrease at ~30Ma while in the western sags the onset was ~23.8Ma. This suggests that the break-up time i.e. the end of rifting in the PRMB is earlier in the eastern sags than in the western sags. Abnormally accelerated tectonic subsidence occurred between 17.5-16.4Ma during the post-rifting stage, at an average subsidence rate as high as 301.9m/Ma. This phenomenon discriminates the PRMB from the category of classical Atlantic passive continental marginal basins, of which the tectonic subsidence during the post-rifting stage decays exponentially. The main objective of this paper is to provide insights into the geological and geodynamic evolution of the PRMB. The result bears significance to hydrocarbon exploration in this region.
Differentiated control of web traffic: a numerical analysis
NASA Astrophysics Data System (ADS)
Guo, Liang; Matta, Ibrahim
2002-07-01
Internet measurements show that the size distribution of Web-based transactions is usually very skewed; a few large requests constitute most of the total traffic. Motivated by the advantages of scheduling algorithms which favor short jobs, we propose to perform differentiated control over Web-based transactions to give preferential service to short web requests. The control is realized through service semantics provided by Internet Traffic Managers, a Diffserv-like architecture. To evaluate the performance of such a control system, it is necessary to have a fast but accurate analytical method. To this end, we model the Internet as a time-shared system and propose a numerical approach which utilizes Kleinrock's conservation law to solve the model. The numerical results are shown to match well those obtained by packet-level simulation, which runs orders of magnitude slower than our numerical method.
NASA Astrophysics Data System (ADS)
Xie, Wen-Jie; Jiang, Zhi-Qiang; Gu, Gao-Feng; Xiong, Xiong; Zhou, Wei-Xing
2015-10-01
Many complex systems generate multifractal time series which are long-range cross-correlated. Numerous methods have been proposed to characterize the multifractal nature of these long-range cross correlations. However, several important issues about these methods are not well understood and most methods consider only one moment order. We study the joint multifractal analysis based on partition function with two moment orders, which was initially invented to investigate fluid fields, and derive analytically several important properties. We apply the method numerically to binomial measures with multifractal cross correlations and bivariate fractional Brownian motions without multifractal cross correlations. For binomial multifractal measures, the explicit expressions of mass function, singularity strength and multifractal spectrum of the cross correlations are derived, which agree excellently with the numerical results. We also apply the method to stock market indexes and unveil intriguing multifractality in the cross correlations of index volatilities.
An alternative basin characteristic for use in estimating impervious area in urban Missouri basins
Southard, R.E.
1986-01-01
A previous regression analysis of flood peaks on urban basins in St. Louis County, Missouri, indicated that the basin characteristics of percentage of impervious area and drainage area were statistically significant for estimating the 2-, 5-, 10-, 25-, 50-. and 100-yr peak discharges at ungaged urban basins. In this statewide regression analysis of the urban basins for Missouri, an alternative basin characteristic called the percentage of developed area was evaluated. A regression analysis of the percentage of developed area (independent variable), resulted in a simple equation for computing percentage of impervious area. The percentage of developed area also was evaluated using flood-frequency data for 23 streamflow gaging stations, and the use of this variable was determined to be valid. Using nationwide data, an urban basin characteristic known as the basin development factor was determined to be valid for inclusion in urban regression equations for estimating flood flows. The basin development factor and the percentage of developed area were compared for use in regression equations to estimate peak flows of streams in Missouri. The equations with the basin development factor produced peak flow estimates with slightly smaller average standard errors of estimate than the equation with the percentage of developed area; however, this study indicates that there was not enough statistical or numerical difference to warrant using the basin development factor instead of the percentage of developed area in Missouri. The selection of a basin characteristic to describe the physical conditions of a drainage basin will depend not only on its contribution to accuracy of regression equations, but also on the ease of determining the characteristics; the percentage of developed area has this advantage. A correlation analysis was made by correlating drainage area to percentage of impervious area, the percentage of developed area, and the basin development factor. The results of
Numerical analysis of stiffened shear webs in the postbuckling range
NASA Technical Reports Server (NTRS)
Stein, M.; Starnes, J. H., Jr.
1973-01-01
The postbuckling behavior of shear webs divided into rectangular panels by stiffeners (uprights) was studied numerically, using the STAGS program in which two-dimensional finite differences are used to solve buckling and nonlinear problems. Universal nondimensional parameters, suggested by linear buckling data, are found to hold for the postbuckling range. Results indicate that the postbuckling stiffness of shear webs with isotropic panels is roughly two thirds of the prebuckling stiffness. The postbuckling behavior of shear webs with isotropic and orthotropic material properties is compared. Some practical aspects of solving nonlinear problems of this type by the numerical method employed are examined.
Numerical analysis of entropy generation in a turbulent diffusion flame
NASA Astrophysics Data System (ADS)
Bouras, F.; Khaldi, F.
2016-01-01
Thermodynamic irreversibilities generated by the combustion process are evaluated and analyzed numerically. The numerical simulation is performed for a reference case study for which experimental data are available in the literature: diffusion flame properties in a common burner configuration are studied by the Fluent software with the standard k-ɛ turbulence model and two-step chemical reaction. The study quantifies the contribution of each mechanism to entropy generation, i.e., friction, heat conduction, species diffusion, and chemical reaction. The chemical reaction and heat conduction are found to be the major sources of entropy production. Preheating of air reduces thermodynamic irreversibilities within the combustor.
Method Study of Flood Hazard Analysis for Plain River Network Area, Taihu Basin, China
NASA Astrophysics Data System (ADS)
HAN, C.; Liu, S.; Zhong, G.; Zhang, X.
2015-12-01
Flood is one of the most common and serious natural calamities. Taihu Basin is located in delta region of the Yangtze River in East China (see Fig. 1). Because of the abundant rainfall and low-lying terrain, the area frequently suffers from flood hazard which have caused serious casualty and economic loss. In order to reduce the severe impacts of floods events, numerous polder areas and hydraulic constructions (including pumps, water gates etc.) were constructed. Flood Hazard Map is an effective non-structural flood mitigation tool measures. Numerical simulation of flood propagation is one of the key technologies of flood hazard mapping. Because of the complexity of its underlying surface characteristics, numerical simulation of flood propagation was faced with some special problems for the plain river network area in Taihu Basin. In this paper, a coupled one and two dimensional hydrodynamic model was established. Densely covered and interconnected river networks, numerous polder areas and complex scheduling hydraulic constructions were generalized in the model. The model was proved to be believable and stable. Based on the results of the simulation of flood propagation, flood hazard map was compiled.
NASA Astrophysics Data System (ADS)
Empinotti, Thais; Spychala, Yvonne; Luthi, Stefan; Hodgson, David
2016-04-01
The depositional architectures of deep-water turbiditic deposits are strongly influenced by seafloor topography. Slope gradient variations of less than one degree might be sufficient to change the distribution of sands significantly along the basin profile. Stratigraphic units of deep-water sandstones from the Fort Brown Fm. in the Laingsburg depocentre (Karoo Basin, South Africa) are an example of that. Regional mapping and stratigraphic correlation of Units C to F (Van der Merwe et al., 2014) show a change from sand-attached systems in Units C and D to sand-detached systems in Units E and F. The sand-attached systems show a continuity of sands from entrenched slope valleys to basin-floor lobe complexes, while in the sand-detached systems there are widespread sand bypass zones of approximately 10 to 30 km where almost no sand is deposited and erosive features are observed. This is interpreted to reflect the development of a stepped slope profile. Lobe deposits occur before and after the bypass region, but significant differences in depositional architecture are noticed between these lobe deposits. The intraslope lobes are characterized by an aggradational to compensational stacking pattern and a common occurrence of erosive features, while the basin floor lobes show a lateral compensating stacking pattern with less erosive features. In this study, process-based numerical modelling of turbidity currents are performed to test if a stepped slope to basin profile with subtle gradient changes similar to that interpreted for the Laingsburg depocentre during the deposition of Unit E are suitable to generate the sediment distribution pattern observed in the field. Through an iterative modelling workflow we aim to constrain the paleoslope gradient changes using the parameters constrained from outcrop. The study also investigates how flow parameters such as sediment concentration, flow velocity, flow thickness and Froude number behave as a function of different slope
NASA Astrophysics Data System (ADS)
Lagmay, A. M. F.; Tengonciang, A. M. P.; Uy, H. S.
2005-06-01
Mayon Volcano is located within the Bicol Basin in the southeastern region of Luzon, Philippines. The basin is contained within a releasing bend associated with the curvature of the central segment of the left-lateral Philippine Fault. A structural analysis of the faults that traverse the Bicol Basin was conducted through reviews of existing literature, seismic data interpretation, and remote sensing; in particular, those structures that may have influenced the growth and evolution of Mayon. Dynamic analysis of the aforementioned structures reveals a regional transtensional stress regime for the Bicol Basin. Field investigation on Mayon's slopes revealed the existence of fractures along its western and eastern flanks. These structures on Mayon have the same geometry as the dominant faults found within the Bicol Basin. Interpretation of these fractures indicates a tectonic control over their origin. The identification of fractures on Mayon's slopes is the first description of such features on its edifice. These new data highlight the probable landslide hazards associated with an oversteepened volcano that may have been further destabilized by tectonic activity.
Wellbore stability analysis and its application in the Fergana basin, central Asia
NASA Astrophysics Data System (ADS)
Chuanliang, Yan; Jingen, Deng; Baohua, Yu; Hailong, Liu; Fucheng, Deng; Zijian, Chen; Lianbo, Hu; Haiyan, Zhu; Qin, Han
2014-02-01
Wellbore instability is one of the major problems hampering the drilling speed in the Fergana basin. Comprehensive analysis of the geological and engineering data in this area indicates that the Fergana basin is characterized by high in situ stress and plenty of natural fractures, especially in the formations which are rich in bedding structure and have several high-pressure systems. Complex accidents such as wellbore collapse, sticking, well kick and lost circulation happen frequently. Tests and theoretical analysis reveals that the wellbore instability in the Fergana basin was influenced by multiple interactive mechanisms dominated by the instability of the bedding shale. Selecting a proper drilling fluid density and improving the sealing characteristic of the applied drilling fluid is the key to preventing wellbore instability in the Fergana basin. The mechanical mechanism of wellbore instability in the Fergana basin was analysed and a method to determine the proper drilling fluid density was proposed. The research results were successfully used to guide the drilling work of the Jida-4 well; compared with the Jida-3 well, the drilling cycle of the Jida-4 well was reduced by 32%.
NASA Astrophysics Data System (ADS)
Sun, Bin; Wang, Liangshu; Dong, Ping; Wu, YongJing; Li, Changbo; Hu, Bo; Wang, Chong
2012-11-01
The Hailar Basin is one of the typical basins among the NE China Basin Groups, which is situated in the east of East Asia Orogene between the Siberia Plate and the North China Plate. Based on the detailed analysis of magnetic, gravity, petrophysical, geothermal and seismological data, we separate the Gravity and Magnetic Anomalies (GMA) into four orders using Wavelet Multi-scale Decomposition (WMD). The apparent depths of causative sources were then assessed by Power Spectrum Analysis (PSA) of each order. Low-order wavelet detail anomalies were used to study the basin's basement structure such as major faults, the basement lithology, uplifts and depressions. High-order ones were used for the inversion of Moho and Curie discontinuities using the Parker method. The results show that the Moho uplifting area of the Hailar Basin is located at the NE part of the basin, the Curie uplifting area is at the NW part, and neither of them is consistent with the basin's sedimentary center. This indicates that the Hailar Basin may differ in basin building pattern from other middle and eastern basins of the basin groups, and the Hailar Basin might be of a passive type. When the Pacific Plate was subducting to NE China, the frontier of the plate lying on the mantle transition zone didn't pass through the Great Khingan Mountains region, so there is not an obvious magma upwelling or lithospheric extension in the Hailar Basin area. Finally, based on the seismological data and results of WMD, a probable 2D crust model is derived from an across-basin profile using the 2D forward modeling of the Bouguer gravity anomaly. The results agree with those from seismic inversion, suggesting WMD is suitable for identifying major crustal density interfaces.
A numerical study of strike-slip bend formation with application to the Salton Sea pull-apart basin
NASA Astrophysics Data System (ADS)
Ye, Jiyang; Liu, Mian; Wang, Hui
2015-03-01
How stepovers of strike-slip faults connect to form bends is a question important for understanding the formation of push-up ranges (restraining bends) and pull-apart basins (releasing bends). We investigated the basic mechanics of this process in a simple three-dimensional viscoelastoplastic finite element model. Our model predicts localized plastic strain within stepovers that may eventually lead to the formation of strike-slip bends. Major parameters controlling strain localization include the relative fault strength, geometry of the fault system, and the plasticity model assumed. Using the Drucker-Prager plasticity model, in which the plastic yield strength of the crust depends on both shear and normal stresses, our results show that a releasing bend is easier to develop than a restraining bend under similar conditions. These results may help explain the formation of the Salton Sea pull-apart basin in Southern California 0.5-0.1 Ma ago, when the stepover between the Imperial Fault and the San Andreas Fault was connected by the Brawley seismic zone.
A spatial analysis of phosphorus in the Mississippi river basin.
Jacobson, Linda M; David, Mark B; Drinkwater, Laurie E
2011-01-01
Phosphorus (P) in rivers in the Mississippi River basin (MRB) contributes to hypoxia in the Gulf of Mexico and impairs local water quality. We analyzed the spatial pattern of P in the MRB to determine the counties with the greatest January to June P riverine yields and the most critical factors related to this P loss. Using a database of P inputs and landscape characteristics from 1997 through 2006 for each county in the MRB, we created regression models relating riverine total P (TP), dissolved reactive P (DRP), and particulate P (PP) yields for watersheds within the MRB to these factors. Riverine yields of P were estimated from the average concentration of each form of P during January to June for the 10-yr period, multiplied by the average daily flow, and then summed for the 6-mo period. The fraction of land planted in crops, human consumption of P, and precipitation were found to best predict TP yields with a spatial error regression model ( = 0.48, = 101). Dissolved reactive P yields were predicted by fertilizer P inputs, human consumption of P, and precipitation in a multiple regression model ( = 0.42, = 73), whereas PP yields were explained by crop fraction, human consumption of P, and soil bulk density in a spatial error regression model ( = 0.49, = 61). Overall, the Upper Midwest's Cornbelt region and lower Mississippi basin had the counties with the greatest P yields. These results help to point out specific areas where agricultural conservation practices that reduce losses to streams and rivers and point source P removal might limit the intensity or spatial occurrence of Gulf of Mexico hypoxia and improve local water quality. PMID:21546679
Numerical analysis of sapphire crystal growth by the Kyropoulos technique
NASA Astrophysics Data System (ADS)
Demina, S. E.; Bystrova, E. N.; Lukanina, M. A.; Mamedov, V. M.; Yuferev, V. S.; Eskov, E. V.; Nikolenko, M. V.; Postolov, V. S.; Kalaev, V. V.
2007-09-01
A numerical model has been suggested to analyze processes occurring during sapphire crystal growth by the Kyropoulos technique. The model accounts for the radiative heat exchange in the crystal and melt convection together with the crystallization front formation. The theoretical predictions agree well with available experimental data.
Finite Element Analysis Of Structural And Magmatic Interactions At Mono Basin (California)
NASA Astrophysics Data System (ADS)
La Marra, D.; Manconi, A.; Battaglia, M.
2010-12-01
Mono Basin is a northward trending graben situated east of the Sierra Nevada and west of Cowtrack Mountains, extending from the northern edge of Long Valley Caldera towards the Bodie Hills. From a hydrographic perspective, the Mono Basin is defined by all streams that drain into Mono Lake. The Mono-Inyo Craters forms a prominent 25-km-long volcanic complex from the NW corner of Long Valley caldera to the southern edge of Mono Lake. The late Quaternary Hartley Springs fault occurs along the Sierran range front between June Lake and the northern border of Long Valley Caldera. Recently it has been proposed that the manifestation of the volcanic and of the tectonic activity in this area is likely interrelated. According to Bursik et al (2003), stratigraphic data suggest that during the North Mono-Inyo eruption sequence of ~1350 A.D., a series of strong earthquakes occurred across the end of the North Mono explosive phase and the beginning of the Inyo explosive phase. Moreover, geological and geomorphic features of the Hartley Springs fault are consistent with rupture of the fault during the eruption sequence. We use the Finite Element Method (FEM) to simulate a three-dimensional model and investigate the feedback mechanism between dike intrusion and slip along the Hartley Springs fault. We first validate our numerical model against the Okada (1985) analytical solution for a homogeneous and elastic flat half-space. Subsequently, we evaluate the distribution of local stress changes to study the influence of the Inyo Dike intrusion in ~1350 A.D. on Hartley Springs fault, and how the fault slip may encourage the propagation of dikes towards the surface. To this end, we considered the standard Coulomb stress change as failure criterion. Finally, we analyze the effects of the topography and of vertical and lateral heterogeneities of the crust on the distribution of local and regional stress changes. In this presentation, we highlight the preliminary results of our analysis
The numerical analysis of a turbulent compressible jet
NASA Astrophysics Data System (ADS)
Debonis, James Raymond
2000-10-01
A numerical method to simulate high Reynolds number jet flows was formulated and applied to gain a better understanding of the flow physics. Large-eddy simulation was chosen as the most promising approach to model the turbulent structures due to its compromise between accuracy and computational expense. The filtered Navier-Stokes equations were developed including a total energy form of the energy equation. Sub-grid scale models for the momentum and energy equations were adapted from compressible forms of Smagorinsky's original model. The effect of using disparate temporal and spatial accuracy in a numerical scheme was discovered through one-dimensional model problems and a new uniformly fourth-order accurate numerical method was developed. Results from two and three dimensional validation exercises show that the code accurately reproduces both viscous and inviscid flows. Numerous axisymmetric jet simulations were performed to investigate the effect of grid resolution, numerical scheme, exit boundary conditions and sub-grid scale modeling on the solution and the results were used to guide the three-dimensional calculations. Three-dimensional calculations of a Mach 1.4 jet showed that this LES simulation accurately captures the physics of the turbulent flow. The agreement with experimental data relatively good and is much better than results in the current literature. Turbulent intensities indicate that the turbulent structures at this level of modeling are not isotropic and this information could lend itself to the development of improved sub-grid scale models for LES and turbulence models for RANS simulations. A two point correlation technique was used to quantify the turbulent structures. Two point space correlations were used to obtain a measure of the integral length scale, which proved to be approximately ½Dj. Two point space-time correlations were used to obtain the convection velocity for the turbulent structures. This velocity ranged from 0.57 to 0.71 Uj.
Numerical Analysis of the Impedance of Fractal Electrodes
NASA Astrophysics Data System (ADS)
Cao, Qi-Zhong
The constant-phase-angle (CPA) impedance observed in electrochemical cells is often thought to be due to fractal roughness on the electrode surface. This idea was pursued by numerous theoretical and experimental studies in the last decade but there is no consensus on the quantitative relationship between the roughness and the impedance. In this study, we consider the partial differential equations that govern the electrostatic potential and the concentrations of anions and cations between two blocking electrodes which have no chemical reactions. We assume that diffusion and conduction are the only transport mechanisms and the Poisson -Boltzmann equation is obeyed. These equations are linearized and solved analytically in one dimension and numerically in two dimensions. For the latter, we used electrodes shaped like Koch curves and saw-tooth curves. A special grid was generated by conformal mapping to fit these boundaries with singularities and the equations are solved by finite -difference method on this grid. The numerical results are compared to the one-dimensional solution that give the behavior of the flat electrode. We find that the only observable effect of surface roughness is that it increases the interfacial capacitance due to the increased surface area. No evidence of the CPA impedance could be seen in our numerical data. We also studied the problem with the boundary-element method. It confirms that the numerical results are rigorously correct in the high and low frequency limit. Requiring the impedance in the intermediate frequency regime to match smoothly with these limits rule out the possibility of a CPA impedance. We suggest that the CPA impedance observed in many experiments is caused either by the adsorption and desorption of ions on the surface, or by oxidation and corrosion on the surface that changed the boundary conditions in the system.
NASA Technical Reports Server (NTRS)
Bowman, Kenneth P.; Sacks, Jerome; Chang, Yue-Fang
1993-01-01
Methods for the design and analysis of numerical experiments that are especially useful and efficient in multidimensional parameter spaces are presented. The analysis method, which is similar to kriging in the spatial analysis literature, fits a statistical model to the output of the numerical model. The method is applied to a fully nonlinear, global, equivalent-barotropic dynamical model. The statistical model also provides estimates for the uncertainty of predicted numerical model output, which can provide guidance on where in the parameter space to conduct further experiments, if necessary. The method can provide significant improvements in the efficiency with which numerical sensitivity experiments are conducted.
Brown, Larry R.
1996-01-01
Available data through 1992 on aquatic biota in the San Joaquin-Tulare Basins study unit of the National Water-Quality Assessment Program were analyzed to provide a conceptual framework to guide study design. The analysis included information on the biology of fish, aquatic macroinvertebrates, aquatic algae, and concentrations of trace elements and organic pesticides in aquatic biota.
NASA Astrophysics Data System (ADS)
Belferman, Mariana; Katsman, Regina; Agnon, Amotz
2015-04-01
The Levant has been repeatedly devastated by numerous earthquakes since prehistorical time, as recorded in historical documents, archaeological ruins, and sedimentary archives. In order to understand the role of the dynamics of the water bodies in triggering the deformations in the Levant basin, a new theoretical thermo-mechanical model is constructed and extended by including a fluid flow component. The latter is modeled on a basis of two-way poroelastic coupling with momentum equation. This coupling is essential to capture the fluid flow evolution induced by dynamic water loading and to resolve porosity changes. All the components of the model, namely elasticity, creep, plasticity, fluid flow, etc., have been extensively verified and presented. Results of the initial sensitivity analysis addressing the relative importance of each process in earthquakes triggering are discussed. The rich archives of pre-instrumental destructive earthquakes will set constraints for future modeling under the present formulation.
Preliminary analysis of ERTS-relayed water resources data in the Delaware River Basin
NASA Technical Reports Server (NTRS)
Paulson, R. W.
1973-01-01
Preliminary analysis of ERTS-DCS data from water-resources stations in the Delaware River Basin indicates that the Data-Collection System is performing well. Data-Collections Platforms have been successfully interfaced with five stream-gaging station and three ground-water observation wells and are being interfaced with 12 water-quality monitors in the basin. Data are being relayed during four or five ERTS orbital passes per day, which is within the design specifications of the ERTS-DCS.
NASA Astrophysics Data System (ADS)
Wichura, Henry; Quinteros, Javier; Melnick, Daniel; Brune, Sascha; Schwanghart, Wolfgang; Strecker, Manfred R.
2015-04-01
Over the last four years sedimentologic and thermochronologic studies in the western and eastern branches of the Cenozoic East African Rift System (EARS) have supported the notion of a broadly contemporaneous onset of normal faulting and rift-basin formation in both segments. These studies support previous interpretations based on geophysical investigations from which an onset of rifting during the Paleogene had been postulated. In light of these studies we explore the evolution of the Lake Victoria basin, a shallow, unfaulted sedimentary basin centered between both branches of the EARS and located in the interior of the East African Plateau (EAP). We quantify the fluvial catchment evolution of the Lake Victoria basin and assess the topographic response of African crust to the onset of rifting in both branches. Furthermore, we evaluate and localize the nature of strain and flexural rift-flank uplift in both branches. We use a 3D numerical forward model that includes nonlinear temperature- and stress-dependent elasto-visco-plastic rheology. The model is able to reproduce the flexural response of variably thick lithosphere to rift-related deformation processes such as lithospheric thinning and asthenospheric upwelling. The model domain covers the entire EAP and integrates extensional processes in a heterogeneous, yet cold and thick cratonic block (Archean Tanzania craton), which is surrounded by mechanically weaker Proterozoic mobile belts, which are characterized by thinner lithosphere ("thin spots"). The lower limits of the craton (170 km) and the mobile belts (120 km) are simulated by different depths of the 1300 °C lithosphere-asthenosphere boundary. We assume a constant extension rate of 4 mm/a throughout the entire simulation of 30 Ma and neglect the effect of dynamic topography and magmatism. Even though the model setup is very simple and the resolution is not high enough to calculate realistic rift-flank uplift, it intriguingly reveals important topographic
An efficient numerical procedure for thermohydrodynamic analysis of cavitating bearings
NASA Technical Reports Server (NTRS)
Vijayaraghavan, D.
1995-01-01
An efficient and accurate numerical procedure to determine the thermo-hydrodynamic performance of cavitating bearings is described. This procedure is based on the earlier development of Elrod for lubricating films, in which the properties across the film thickness are determined at Lobatto points and their distributions are expressed by collocated polynomials. The cavitated regions and their boundaries are rigorously treated. Thermal boundary conditions at the surfaces, including heat dissipation through the metal to the ambient, are incorporated. Numerical examples are presented comparing the predictions using this procedure with earlier theoretical predictions and experimental data. With a few points across the film thickness and across the journal and the bearing in the radial direction, the temperature profile is very well predicted.
Numerical analysis of nanostructures for enhanced light extraction from OLEDs
NASA Astrophysics Data System (ADS)
Zschiedrich, Lin; Greiner, Horst J.; Burger, Sven; Schmidt, Frank
2013-03-01
Nanostructures, like periodic arrays of scatters or low-index gratings, are used to improve the light outcoupling from organic light-emitting diodes (OLED). In order to optimize geometrical and material properties of such structures, simulations of the outcoupling process are very helpful. The finite element method is best suited for an accurate discretization of the geometry and the singular-like field profile within the structured layer and the emitting layer. However, a finite element simulation of the overall OLED stack is often beyond available computer resources. The main focus of this paper is the simulation of a single dipole source embedded into a twofold infinitely periodic OLED structure. To overcome the numerical burden we apply the Floquet transform, so that the computational domain reduces to the unit cell. The relevant outcoupling data are than gained by inverse Flouqet transforming. This step requires a careful numerical treatment as reported in this paper.
Analysis of the numerics of physics-dynamics coupling
NASA Astrophysics Data System (ADS)
Staniforth, Andrew; Wood, Nigel; Côté, Jean
2002-10-01
A methodology for analysing the numerical properties of schemes for coupling physics parametrizations to a dynamical core is presented. As an example of its application, the methodology is used to study four coupling schemes ('explicit', 'implicit', 'split-implicit' and 'symmetrized split-implicit') in the context of a semi-implicit semi-Lagrangian dynamical core. Each coupling scheme is assessed in terms of its numerical stability and of the accuracy of both its transient and steady-state responses. Additionally, the occurrence of spurious, computational resonance is analysed and discussed. It is found that in this respect all four schemes behave similarly.In particular, in the absence of any damping mechanism to control resonance, the time-step restriction needed to avoid spurious resonance is twice as restrictive for time-dependent forcing as for stationary forcing.
Numerical analysis of a microwave torch with axial gas injection
Gritsinin, S. I.; Davydov, A. M.; Kossyi, I. A.; Kulumbaev, E. B.; Lelevkin, V. M.
2013-07-15
The characteristics of a microwave discharge in an argon jet injected axially into a coaxial channel with a shortened inner electrode are numerically analyzed using a self-consistent equilibrium gas-dynamic model. The specific features of the excitation and maintenance of the microwave discharge are determined, and the dependences of the discharge characteristics on the supplied electromagnetic power and gas flow rate are obtained. The calculated results are compared with experimental data.
Numerical analysis for the optimum condition of ultrasonic nebulizing
NASA Astrophysics Data System (ADS)
Kim, Jungsoon; Kim, Jihyang; Ha, Kanglyeol; Kim, Moojoon
2016-07-01
To obtain the optimal driving conditions for ultrasonic nebulizing, the capillary wave caused by ultrasound on the water surface was analyzed theoretically. From the possible solutions of Mathieu’s equation, the condition for amplitude diverging with time changes was investigated. The possible ranges of the driving frequency and the vibration displacement for nebulizing were obtained numerically, and the droplet size distribution was obtained in these ranges. The results of this study could be applied to design the desirable ultrasonic nebulizer.
NASA Astrophysics Data System (ADS)
Gamboa, Davide; Williams, John; Kirk, Karen; Gent, Christopher; Bentham, Michelle; Fellgett, Mark; Schofield, David
2016-04-01
Carbon Capture and Storage (CCS) is a vital technology towards low-carbon energy resources and the mitigation of global warming trends induced by rising CO2 levels in the atmosphere. The East Irish Sea Basin (EISB) is a key area for CCS in the western UK, having high CO2 storage potentials in explored hydrocarbon fields and in saline aquifers within the Permo-Triassic Sherwood Sandstone Formation. However, the theoretical storage potential of the EISB could be poorly estimated as the reservoir-prone Lower Permian formations are not considered in detail by current estimations. This work aims to fill this gap, focusing on the characterisation of the Lower Permian Collyhurst Sandstone Formation as a viable storage unit. The potential for CO2 storage is estimated as the total volume/area of suitable closures that are isolated by structural traps, occurring at depths suitable for CO2 injection and containment (>800m). Detailed structural and stratigraphic interpretations were made using 3D seismic data to assess the storage potential of the Collyhurst Sandstone Formation in the southern EISB. The basin strata is compartmentalised by numerous N-S trending faults. A higher degree of compartmentalisation occurs within regional anticlines where elongated tilted blocks are observed, bound by predominantly west-dipping faults that induce a variable offset of the Collyhurst Sandstone strata. Contrastingly, higher lateral continuity of this formation is observed within graben basins were faults are less frequent and with minor offset, thus potentially creating larger storage closures. Fault dip orientation in the grabens is variable, with west and east dipping faults occurring as a function of large east-dipping listric faults. This study was complemented by the stress modelling of the interpreted faults in order to assess the risk of CO2 leakage. Analysis of borehole breakouts observed in four approximately vertical wells in the EISB suggest a maximum horizontal stress
Numerical bifurcation analysis of the bipedal spring-mass model
NASA Astrophysics Data System (ADS)
Merker, Andreas; Kaiser, Dieter; Hermann, Martin
2015-01-01
The spring-mass model and its numerous extensions are currently one of the best candidates for templates of human and animal locomotion. However, with increasing complexity, their applications can become very time-consuming. In this paper, we present an approach that is based on the calculation of bifurcations in the bipedal spring-mass model for walking. Since the bifurcations limit the region of stable walking, locomotion can be studied by computing the corresponding boundaries. Originally, the model was implemented as a hybrid dynamical system. Our new approach consists of the transformation of the series of initial value problems on different intervals into a single boundary value problem. Using this technique, discontinuities can be avoided and sophisticated numerical methods for studying parametrized nonlinear boundary value problems can be applied. Thus, appropriate extended systems are used to compute transcritical and period-doubling bifurcation points as well as turning points. We show that the resulting boundary value problems can be solved by the simple shooting method with sufficient accuracy, making the application of the more extensive multiple shooting superfluous. The proposed approach is fast, robust to numerical perturbations and allows determining complete manifolds of periodic solutions of the original problem.
Numerical and semiclassical analysis of some generalized Casimir pistons
Schaden, M.
2009-05-15
The Casimir force due to a scalar field in a cylinder of radius r with a spherical cap of radius R>r is computed numerically in the world-line approach. A geometrical subtraction scheme gives the finite interaction energy that determines the Casimir force. The spectral function of convex domains is obtained from a probability measure on convex surfaces that is induced by the Wiener measure on Brownian bridges the convex surfaces are the hulls of. Due to reflection positivity, the vacuum force on the piston by a scalar field satisfying Dirichlet boundary conditions is attractive in these geometries, but the strength and short-distance behavior of the force depend strongly on the shape of the piston casing. For a cylindrical casing with a hemispherical head, the force on the piston does not depend on the dimension of the casing at small piston elevation a<
Numerical analysis of biosonar beamforming mechanisms and strategies in bats.
Müller, Rolf
2010-09-01
Beamforming is critical to the function of most sonar systems. The conspicuous noseleaf and pinna shapes in bats suggest that beamforming mechanisms based on diffraction of the outgoing and incoming ultrasonic waves play a major role in bat biosonar. Numerical methods can be used to investigate the relationships between baffle geometry, acoustic mechanisms, and resulting beampatterns. Key advantages of numerical approaches are: efficient, high-resolution estimation of beampatterns, spatially dense predictions of near-field amplitudes, and the malleability of the underlying shape representations. A numerical approach that combines near-field predictions based on a finite-element formulation for harmonic solutions to the Helmholtz equation with a free-field projection based on the Kirchhoff integral to obtain estimates of the far-field beampattern is reviewed. This method has been used to predict physical beamforming mechanisms such as frequency-dependent beamforming with half-open resonance cavities in the noseleaf of horseshoe bats and beam narrowing through extension of the pinna aperture with skin folds in false vampire bats. The fine structure of biosonar beampatterns is discussed for the case of the Chinese noctule and methods for assessing the spatial information conveyed by beampatterns are demonstrated for the brown long-eared bat. PMID:20815475
Numerical Analysis of Electromagnetic Fields in Multiscale Model
NASA Astrophysics Data System (ADS)
Ma, Ji; Fang, Guang-You; Ji, Yi-Cai
2015-04-01
Modeling technique for electromagnetic fields excited by antennas is an important topic in computational electromagnetics, which is concerned with the numerical solution of Maxwell's equations. In this paper, a novel hybrid technique that combines method of moments (MoM) with finite-difference time-domain (FDTD) method is presented to handle the problem. This approach employed Huygen's principle to realize the hybridization of the two classical numerical algorithms. For wideband electromagnetic data, the interpolation scheme is used in the MoM based on the dyadic Green's function. On the other hand, with the help of equivalence principle, the scattered electric and magnetic fields on the Huygen's surface calculated by MoM are taken as the sources for FDTD. Therefore, the electromagnetic fields in the environment can be obtained by employing finite-difference time-domain method. Finally, numerical results show the validity of the proposed technique by analyzing two canonical samples. Supported in part by China Postdoctoral Science Foundation under Grant No. 201M550839, and in part by the Key Research Program of the Chinese Academy of Sciences under Grant No. KGZD-EW-603
Experimental and Numerical Analysis of Inserts in Sandwich Structures
NASA Astrophysics Data System (ADS)
Bunyawanichakul, P.; Castanie, B.; Barrau, J.-J.
2005-05-01
In aeronautics, sandwich structures are widely used for secondary structures like flaps or landing gear doors. In the case of landing gear doors, the junction is made by a local reinforcement called an insert. This insert is made by a resin molded in the Nomex™ sandwich core. Such structures are still designed mainly using test results and the lack of an efficient numerical model remains a problem. The purpose of this study is on the one hand to perform experiments in order to be able to identify the failure modes and on the other hand to propose an efficient numerical model. Pull-out tests with cycling were conducted and 3D displacement measured by optical methods. The potential failure modes are numerous (delamination, local fiber breaking, skin/core debonding, core crushing, core shear buckling, potting failure, etc.). Experiments demonstrated that, for the lower loads, the non-linearity and the hysteresis are mainly due to core shear buckling. From this observation, the nonlinear behavior of the core is identified by a 3 point-bending test. The shear-modulus damage law is then implemented on a non-linear finite element model and an acceptable correlation of the tests is achieved. As a consequence, some improvements of the technology will be proposed, manufactured and tested.
Fish Pectoral Fin Hydrodynamics; Part II: Numerical Simulations and Analysis
NASA Astrophysics Data System (ADS)
Dong, H.; Madden, P. G.
2005-11-01
High-fidelity numerical simulations are being used to examine the key hydrodynamic features and thrust performance of the pectoral fin of a bluegill sunfish which is moving at a constant forward velocity. The numerical modeling approach employs a parallelized immersed boundary solver which can perform direct (DNS) or large-eddy simulation (LES) of flow past highly deformable bodies such as fish pectoral fins. The three-dimensional, time-dependent fin kinematics is obtained via a stereo-videographic technique and experiments also provide PIV data which is used to validate the numerical simulations. The primary objectives of the CFD effort are to quantify the thrust performance of the bluegill sunfish pectoral fin as well as to establish the mechanisms responsible for thrust production. Simulations show that the pectoral fin produces a relatively large amount of thrust at all phases in the fin motion while limiting the magnitude of the transverse forces. The motion of the fin produces a distinct system of connected vortices which are examined in detail in order to gain insight into the thrust producing mechanisms.
Analysis of future precipitation in the Koshi river basin, Nepal
NASA Astrophysics Data System (ADS)
Agarwal, Anshul; Babel, Mukand S.; Maskey, Shreedhar
2014-05-01
We analyzed precipitation projections for the Koshi river basin in Nepal using outputs from 10 General Circulation Models (GCMs) under three emission scenarios (B1, A1B and A2). The low resolution future precipitation data obtained from the GCMs was downscaled using the statistical downscaling model LARS-WG. The data was downscaled for 48 stations located in the six physiographic regions in the Koshi basin. The precipitation projections for three future periods, i.e. 2020s, 2055s and 2090s, are presented using empirical Probability Density Functions (PDFs) for each physiographic region. The differences between the mean values of individual GCM projections and the mean value of the multi-model for the three scenarios allow for the estimation of uncertainty in the projections. We also analyzed the precipitation of the baseline and future periods using six indices that are recommended by the Expert Team on Climate Change Detection, Monitoring and Indices (ETCCDMI). Results indicate that not all GCMs agree on weather changes in precipitation will be positive or negative. A majority of the GCMs and the average values of all the GCMs for each scenario, indicate a positive change in summer, autumn and annual precipitation but a negative change in spring precipitation. Differences in the GCM projections exist for all the three future periods and the differences increase with time. The estimated uncertainty is higher for scenario A1B compared to B1 and A2. Differences among scenarios are small during the 2020s, which become significant during the 2055s and 2090s. The length of the wet spell is expected to increase, whereas the length of the dry spell is expected to decrease in all three future periods. There is a large scatter in the values of the indices: number of days with precipitation above 20 mm, 1-day maximum precipitation, 5-day maximum precipitation, and amount of precipitation on the days with precipitation above 95th percentile, both in direction and magnitude of
Howell, P.D.; Budai, J.M.
1989-03-01
Quantitative paleobathymetry is difficult to determine for any rock sequence with a significant subtidal component. Water depth estimates are traditionally obtained from detailed sedimentology and paleontology, but this type of data is seldom available in subsurface work. Further, a good geological data base may be inconclusive for paleobathymetry in subtidal or substorm-wave base environments. More accurate facies prediction would be possible if paleobathymetry could be determined from the conventional subsurface data normally available to explorationists. Subsidence analysis of sedimentary basins has the potential to provide precise paleobathymetric estimates for a variety of depositional settings. This technique is illustrated using the Middle Ordovician carbonates of the Michigan basin. Tectonic subsidence patterns established from stratigraphic and subsidence modeling of the Lower-Middle Ordovician Prairie du Chien Group in Michigan are projected forward through the Middle Ordovician. Isopach thicknesses of the Black River and Trenton carbonates are superimposed on the tectonic subsidence patterns to provide a quantitative basin-fill model. The model paleobathymetry is then compared with core data from exploration wells to evaluate the model facies interpretation. An excellent fit is achieved for the shallow to deep subtidal platform and basinal Trenton carbonates. This technique allows paleobathymetry to be calculated in many basins where tectonic subsidence patterns can be accurately modeled.
NASA Astrophysics Data System (ADS)
Chang, Hsiao-Tung
2016-06-01
Urban Heat Island (UHI) has been becoming a key factor in deteriorating the urban ecological environment. Spatial-temporal analysis on its prototype of basin city's UHI and quantitatively evaluating effect from rapid urbanization will provide theoretical foundation for relieving UHI effect. Based on Landsat 8, ETM+ and TM images of Taipei basin areas from 1900 to 2015, this article has retrieved the land surface temperature (LST) at summer solstice of each year, and then analysed spatial-temporal pattern and evolution characters of UHI in Taipei basin in this decade. The results showed that the expansion built district, UHI area constantly expanded from centre city to the suburb areas. The prototype of UHI in Taipei basin that showed in addition to higher temperatures in the centre city also were relatively high temperatures gathered boundaries surrounded by foot of mountains side. It calls "sinking heat island". From 1900 to 2000, the higher UHI areas were different land use type change had obvious difference by public infrastructure works. And then, in next 15 years till 2015, building density of urban area has been increasing gradually. It has the trend that UHI flooding raises follow urban land use density. Hot spot of UHI in Taipei basin also has the same characteristics. The results suggest that anthropogenic heat release probably plays a significant role in the UHI effect, and must be considered in urban planning adaptation strategies.
NASA Astrophysics Data System (ADS)
Zhi, Y.; Yang, Z. F.; Yin, X. A.
2013-12-01
Decomposition analysis of water footprint (WF) changes, or assessing the changes in WF and identifying the contributions of factors leading to the changes, is important to water resource management. However, conventional studies focus on WF from the perspective of administrative region rather than river basin. Decomposition analysis of WF changes from the perspective of the river basin is more scientific. To address this perspective, we built a framework in which the input-output (IO) model and the Structural Decomposition Analysis (SDA) model for WF could be implemented in a river basin by computing IO data for the river basin with the Generating Regional IO Tables (GRIT) method. This framework is illustrated in the Haihe River Basin (HRB), which is a typical water-limited river basin. It shows that the total WF in the HRB increased from 4.3 × 1010 m3 in 2002 to 5.6 × 1010 m3 in 2007, and the agriculture sector makes the dominant contribution to the increase. Both the WF of domestic products (internal) and the WF of imported products (external) increased, and the proportion of external WF rose from 29.1% to 34.4%. The technological effect was the dominant contributor to offsetting the increase of WF; however, the growth of WF caused by the economic structural effect and the scale effect was greater, so the total WF increased. This study provides insights about water challenges in the HRB and proposes possible strategies for the future, and serves as a reference for WF management and policy making in other water-limited river basins.
Lower Permian Dry Mountain trough, eastern Nevada: preliminary basin analysis
Schwarz, D.L.; Snyder, W.S.; Spinosa, C.
1987-08-01
The Lower Permian Dry Mountain trough (DMT) is one of several basins that developed during the Late Pennsylvanian to Permian along the western edge of the North American continent. A tectonic mechanism has been suggested for the subsidence of the DMT, possibly due to reactivation of the Antler orogenic belt during the waning stages of Ancestral Rocky Mountain deformation. The DMT records marked subsidence with the appearance during the Artinskian (latest Wolfcampian) of a deeper water facies that consists of thin-bedded silty micrites and micritic mudstones rich in radiolarians and sponge spicules, characterized by a relative abundance of ammonoids, and rarer conodonts and Nereites ichnofacies trace fossils. Taxa recovered from a distinctive concretionary horizon at various locations provide an Artinskian datum on which to palinspastically reconstruct the DMT paleogeography. These taxa include ammonoids: Uraloceras, Medlicottia, Marathonites, Crimites, Metalegoceras, properrinitids; and conodonts: Neogondolella bisselli, Sweetognathus whitei, S. behnkeni, and Diplognathodus stevensi. The western margin facies of the DMT consists of Permian Carbon Ridge/Garden Valley Formations. Here, lowermost black Artinskianage euxinic micrites, considered a potential source rock for petroleum generation, are overlain by base-of-slope carbonate apron deposits, which, in turn, are overlain by base-of-slope carbonate apron deposits, which, in turn, are overlain by a thick, eastwardly prograding conglomerate wedge. Seismic profiles across Diamond Valley indicate a 3.0-4.6-km thick Tertiary sequence above the Paleozoic strata.
Application of Integrated Flood Analysis System (IFAS) for Dungun River Basin
NASA Astrophysics Data System (ADS)
Hafiz, I.; Nor, N. D. M.; Sidek, L. M.; Basri, H.; K, F.; Hanapi, M. N.; L, Livia
2013-06-01
The Northeast monsoon happening during the months of October until January is the major rainy season found in the eastern part of Peninsular Malaysia. The Dungun river basin (1,858 km2) is exposed to this season thus experiencing characteristically regular flooding due to the prolong rainfall events. The annual rainfall over the river basins are 2,880 mm with great proportion falling in the months of December (19.4%). This study is to apply the Integrated Flood Analysis System (IFAS) model which Dungun river basin has been chosen for this study as the catchments have range of flood and relevant data that can be used to develop the model. The satellite data used in this study is provided by JAXA Global Rainfall Watch. The main feature of this real-time flood analysis model is the satellite-based rainfall data input employed during the model creation phase. The performance of the model for the river basins from satellite and ground-based rainfall data are compared using three error analysis methods.
NASA Astrophysics Data System (ADS)
Horvath, K.; Ivančan-Picek, B.
2009-03-01
A 12-15 November 2004 cyclone on the lee side of the Atlas Mountains and the related occurrence of severe bora along the eastern Adriatic coast are numerically analyzed using the MM5 mesoscale model. Motivated by the fact that sub-synoptic scales are more sensitive to initialization errors and dominate forecast error growth, this study is designed in order to assess the sensitivity of the mesoscale forecast to the intensity of mesoscale potential vorticity (PV) anomalies. Five sensitivity simulations are performed after subtracting the selected anomalies from the initial conditions, allowing for the analysis of the cyclone intensity and track, and additionally, the associated severe bora in the Adriatic. The results of the ensemble show that the cyclone is highly sensitive to the exact details of the upper-level dynamic forcing. The spread of cyclone intensities is the greatest in the mature phase of the cyclone lifecycle, due to different cyclone advection speeds towards the Mediterranean. However, the cyclone tracks diffluence appears to be the greatest during the cyclone movement out of the Atlas lee, prior to the mature stage of cyclone development, most likely due to the predominant upper-level steering control and its influence on the thermal anomaly creation in the mountain lee. Furthermore, it is quantitatively shown that the southern Adriatic bora is more sensitive to cyclone presence in the Mediterranean then bora in the northern Adriatic, due to unequal influence of the cyclone on the cross-mountain pressure gradient formation. The orographically induced pressure perturbation is strongly correlated with bora in the northern and to a lesser extent in the southern Adriatic, implying the existence of additional controlling mechanisms to bora in the southern part of the basin. In addition, it is shown that the bora intensity in the southern Adriatic is highly sensitive to the precise sub-synoptic pressure distribution in the cyclone itself, indicating a
FUTURE WATER ALLOCATION AND IN-STREAM VALUES IN THE WILLAMETTE RIVER BASIN: A BASIN-WIDE ANALYSIS
Our research investigated the impact on surface water resources of three different scenarios for the future development of the Willamette River Basin in Oregon (USA). Water rights in the basin, and in the western United States in general, are based on a system of law that binds ...
Analysis and modeling of subgrid scalar mixing using numerical data
NASA Technical Reports Server (NTRS)
Girimaji, Sharath S.; Zhou, YE
1995-01-01
Direct numerical simulations (DNS) of passive scalar mixing in isotropic turbulence is used to study, analyze and, subsequently, model the role of small (subgrid) scales in the mixing process. In particular, we attempt to model the dissipation of the large scale (supergrid) scalar fluctuations caused by the subgrid scales by decomposing it into two parts: (1) the effect due to the interaction among the subgrid scales; and (2) the effect due to interaction between the supergrid and the subgrid scales. Model comparisons with DNS data show good agreement. This model is expected to be useful in the large eddy simulations of scalar mixing and reaction.
Numerical analysis of heat input effects in thermography
Tossell, D.A.
1987-06-01
A numerical model, suited for use on microcomputers, has been developed to examine the effect of heat input function on surface temperature contrast for passive thermographic NDE. Single and double step input functions have been compared, and the effects of varying pulse length and power, defect condition, defect depth to diameter ratio, and maximum allowed front face temperature rise examined. Results indicate that a two-step heat input function enhances the generated surface temperature contrast by up to 10% over the single pulse and compares well with that generated by contact heating.
Preliminary numerical analysis of improved gas chromatograph model
NASA Technical Reports Server (NTRS)
Woodrow, P. T.
1973-01-01
A mathematical model for the gas chromatograph was developed which incorporates the heretofore neglected transport mechanisms of intraparticle diffusion and rates of adsorption. Because a closed-form analytical solution to the model does not appear realizable, techniques for the numerical solution of the model equations are being investigated. Criteria were developed for using a finite terminal boundary condition in place of an infinite boundary condition used in analytical solution techniques. The class of weighted residual methods known as orthogonal collocation is presently being investigated and appears promising.
NASA Astrophysics Data System (ADS)
Carniello, L.; Silvestri, S.; Marani, M.; D'Alpaos, A.; Volpe, V.; Defina, A.
2014-04-01
The morphological evolution of shallow tidal systems strongly depends on gradients in transport that control sediment erosion and deposition. A spatially refined quantitative description of suspended sediment patterns and dynamics is therefore a key requirement to address issues connected with dynamical trends, responses, and conservation of these systems. Here we use a combination of numerical models of sediment transport dynamics, high temporal resolution point observations, and high spatial resolution remote sensing data to overcome the intrinsic limitations of traditional monitoring approaches and to establish the robustness of numerical models in reproducing space-time suspended sediment concentration (SSC) patterns. The comparison of SSC distributions in the Venice Lagoon (Italy) computed with a numerical model with SSC retrievals from remote sensing data allows us to define the ability of the model to properly describe spatial patterns and gradients in the SSC fields. The use of point observations similarly allows us to constrain the model temporally, thus leading to a complete space-time evaluation of model abilities. Our results highlight the fundamental control exerted on sediment transport intensity and patterns by the sheltering effect associated with artificial and natural intertidal landforms. Furthermore, we show how the stabilizing effect of benthic vegetation is a main control of sediment dynamics at the system scale, confirming a notion previously established in the laboratory or at small field scales.
Lightning climatology in the Congo Basin: detailed analysis
NASA Astrophysics Data System (ADS)
Soula, Serge; Kigotsi, Jean; Georgis, Jean-François; Barthe, Christelle
2016-04-01
The lightning climatology of the Congo Basin including several countries of Central Africa is analyzed in detail for the first time. It is based on World Wide Lightning Location Network (WWLLN) data for the period from 2005 to 2013. A comparison of these data with the Lightning Imaging Sensor (LIS) data for the same period shows the WWLLN detection efficiency (DE) in the region increases from about 1.70 % in the beginning of the period to 5.90 % in 2013, relative to LIS data, but not uniformly over the whole 2750 km × 2750 km area. Both the annual flash density and the number of stormy days show sharp maximum values localized in eastern of Democratic Republic of Congo (DRC) and west of Kivu Lake, regardless of the reference year and the period of the year. These maxima reach 12.86 fl km-2 and 189 days, respectively, in 2013, and correspond with a very active region located at the rear of the Virunga mountain range characterised with summits that can reach 3000 m. The presence of this range plays a role in the thunderstorm development along the year. The estimation of this local maximum of the lightning density by taking into account the DE, leads to a value consistent with that of the global climatology by Christian et al. (2003) and other authors. Thus, a mean maximum value of about 157 fl km-2 y-1 is found for the annual lightning density. The zonal distribution of the lightning flashes exhibits a maximum between 1°S and 2°S and about 56 % of the flashes located below the equator in the 10°S - 10°N interval. The diurnal evolution of the flash rate has a maximum between 1400 and 1700 UTC, according to the reference year, in agreement with previous works in other regions of the world.
Numerical analysis and prediction of laser forming of thin plate
NASA Astrophysics Data System (ADS)
Tamsaout, Toufik; Amara, EL-Hachemi
2012-03-01
Laser forming is a technique consisting in the design and the construction of complex metallic work-pieces with special shapes, difficult to achieve with the conventional techniques. By using lasers, the main advantage of the process is that it is contactless and does not require any external force. It offers also more flexibility for a lower price. This kind of processing interests the industries that use the stamping or other costly ways for prototypes such as in the aero-spatial, automotive, naval and microelectronics industries. The analytical modeling of laser forming process is often complex or impossible to achieve, since the dimensions and the mechanical properties change with the time and in the space. Therefore, the numerical approach is more suitable for laser forming modeling. Our numerical study is divided into two models, the first one is a purely thermal treatment which allows the determination of the temperature field produced by a laser pass, and the second one consists in the thermomechanical coupling treatment. The temperature field resulting from the first stage is used to calculate the stress field, the deformations and the bending angle of the plate. The thermo-mechanical properties of material are isotropic, but temperature-dependant.
Numerical analysis and prediction of laser forming of thin plate
NASA Astrophysics Data System (ADS)
Tamsaout, Toufik; Amara, EL-Hachemi
2011-11-01
Laser forming is a technique consisting in the design and the construction of complex metallic work-pieces with special shapes, difficult to achieve with the conventional techniques. By using lasers, the main advantage of the process is that it is contactless and does not require any external force. It offers also more flexibility for a lower price. This kind of processing interests the industries that use the stamping or other costly ways for prototypes such as in the aero-spatial, automotive, naval and microelectronics industries. The analytical modeling of laser forming process is often complex or impossible to achieve, since the dimensions and the mechanical properties change with the time and in the space. Therefore, the numerical approach is more suitable for laser forming modeling. Our numerical study is divided into two models, the first one is a purely thermal treatment which allows the determination of the temperature field produced by a laser pass, and the second one consists in the thermomechanical coupling treatment. The temperature field resulting from the first stage is used to calculate the stress field, the deformations and the bending angle of the plate. The thermo-mechanical properties of material are isotropic, but temperature-dependant.
Numerical analysis of the spatial range of the Kondo effect
Busser, C. A.; Martins, G. B.; Ribeiro, L. Costa; Vernek, E.; Anda, E. V.; Dagotto, Elbio R
2010-01-01
The spatial length of the Kondo screening is still a controversial issue related to Kondo physics. While renormalization-group and Bethe-Ansatz solutions have provided detailed information about the thermodynamics of magnetic impurities, they are insufficient to study the effect on the surrounding electrons, i.e., the spatial range of the correlations created by the Kondo effect between the localized magnetic moment and the conduction electrons. The objective of this work is to present a quantitative way of measuring the extension of these correlations by studying their effect directly on the local density of states (LDOS) at arbitrary distances from the impurity. The numerical techniques used, the embedded cluster approximation, the finite-U slave bosons, and numerical renormalization group, calculate the Green s functions in real space. With this information, one can calculate how the local density of states away from the impurity is modified by its presence, below and above the Kondo temperature, and then estimate the range of the disturbances in the noninteracting Fermi sea due to the Kondo effect, and how it changes with the Kondo temperature TK. The results obtained agree with results obtained through spin-spin correlations, showing that the LDOS captures the phenomenology of the Kondo cloud as well.
Numerical analysis of electrical defibrillation. The parallel approach.
Ng, K T; Hutchinson, S A; Gao, S
1995-01-01
Numerical modeling offers a viable tool for studying electrical defibrillation, allowing the behavior of field quantities to be observed easily as the different system parameters are varied. One numerical technique, namely the finite-element method, has been found particularly effective for modeling complex thoracic anatomies. However, an accurate finite-element model of the thorax often requires a large number of elements and nodes, leading to a large set of equations that cannot be solved effectively with the computational power of conventional computers. This is especially true if many finite-element solutions need to be achieved within a reasonable time period (eg, electrode configuration optimization). In this study, the use of massively parallel computers to provide the memory and reduction in solution time for solving these large finite-element problems is discussed. Both the uniform and unstructured grid approaches are considered. Algorithms that allow efficient mapping of uniform and unstructured grids to data-parallel and message-passing parallel computers are discussed. An automatic iterative procedure for electrode configuration optimization is presented. The procedure is based on the minimization of an objective function using the parallel direct search technique. Computational performance results are presented together with simulation results. PMID:8656104
Numerical solution-space analysis of satisfiability problems
NASA Astrophysics Data System (ADS)
Mann, Alexander; Hartmann, A. K.
2010-11-01
The solution-space structure of the three-satisfiability problem (3-SAT) is studied as a function of the control parameter α (ratio of the number of clauses to the number of variables) using numerical simulations. For this purpose one has to sample the solution space with uniform weight. It is shown here that standard stochastic local-search (SLS) algorithms like average satisfiability (ASAT) exhibit a sampling bias, as does “Metropolis-coupled Markov chain Monte Carlo” (MCMCMC) (also known as “parallel tempering”) when run for feasible times. Nevertheless, unbiased samples of solutions can be obtained using the “ballistic-networking approach,” which is introduced here. It is a generalization of “ballistic search” methods and yields also a cluster structure of the solution space. As application, solutions of 3-SAT instances are generated using ASAT plus ballistic networking. The numerical results are compatible with a previous analytical prediction of a simple solution-space structure for small values of α and a transition to a clustered phase at αc≈3.86 , where the solution space breaks up into several non-negligible clusters. Furthermore, in the thermodynamic limit there are, even for α=4.25 close to the SAT-UNSAT transition αs≈4.267 , always clusters without any frozen variables. This may explain why some SLS algorithms are able to solve very large 3-SAT instances close to the SAT-UNSAT transition.
Numerical solution-space analysis of satisfiability problems.
Mann, Alexander; Hartmann, A K
2010-11-01
The solution-space structure of the three-satisfiability problem (3-SAT) is studied as a function of the control parameter α (ratio of the number of clauses to the number of variables) using numerical simulations. For this purpose one has to sample the solution space with uniform weight. It is shown here that standard stochastic local-search (SLS) algorithms like average satisfiability (ASAT) exhibit a sampling bias, as does "Metropolis-coupled Markov chain Monte Carlo" (MCMCMC) (also known as "parallel tempering") when run for feasible times. Nevertheless, unbiased samples of solutions can be obtained using the "ballistic-networking approach," which is introduced here. It is a generalization of "ballistic search" methods and yields also a cluster structure of the solution space. As application, solutions of 3-SAT instances are generated using ASAT plus ballistic networking. The numerical results are compatible with a previous analytical prediction of a simple solution-space structure for small values of α and a transition to a clustered phase at α(c)≈3.86 , where the solution space breaks up into several non-negligible clusters. Furthermore, in the thermodynamic limit there are, even for α=4.25 close to the SAT-UNSAT transition α(s)≈4.267 , always clusters without any frozen variables. This may explain why some SLS algorithms are able to solve very large 3-SAT instances close to the SAT-UNSAT transition. PMID:21230614
Numerical Analysis of Transient Temperature Response of Soap Film
NASA Astrophysics Data System (ADS)
Tanaka, Seiichi; Tatesaku, Akihiro; Dantsuka, Yuki; Fujiwara, Seiji; Kunimine, Kanji
2015-11-01
Measurements of thermophysical properties of thin liquid films are important to understand interfacial phenomena due to film structures composed of amphiphilic molecules in soap film, phospholipid bilayer of biological cell and emulsion. A transient hot-wire technique for liquid films less than 1 \\upmu m thick such as soap film has been proposed to measure the thermal conductivity and diffusivity simultaneously. Two-dimensional heat conduction equations for a solid cylinder with a liquid film have been solved numerically. The temperature of a thin wire with liquid film increases steeply with its own heat generation. The feasibility of this technique is verified through numerical experiments for various thermal conductivities, diffusivities, and film thicknesses. Calculated results indicate that the increase in the volumetric average temperature of the thin wire sufficiently varies with the change of thermal conductivity and diffusivity of the soap film. Therefore, the temperature characteristics could be utilized to evaluate both the thermal conductivity and diffusivity using the Gauss-Newton method.
Notes on numerical reliability of several statistical analysis programs
Landwehr, J.M.; Tasker, Gary D.
1999-01-01
This report presents a benchmark analysis of several statistical analysis programs currently in use in the USGS. The benchmark consists of a comparison between the values provided by a statistical analysis program for variables in the reference data set ANASTY and their known or calculated theoretical values. The ANASTY data set is an amendment of the Wilkinson NASTY data set that has been used in the statistical literature to assess the reliability (computational correctness) of calculated analytical results.
Ernest A. Mancini; Paul Aharon; Donald A. Goddard; Roger Barnaby
2006-05-26
The principal research effort for Phase 1 (Concept Development) of the project has been data compilation; determination of the tectonic, depositional, burial, and thermal maturation histories of the North Louisiana Salt Basin; basin modeling (geohistory, thermal maturation, hydrocarbon expulsion); petroleum system identification; comparative basin evaluation; and resource assessment. Existing information on the North Louisiana Salt Basin has been evaluated, an electronic database has been developed, and regional cross sections have been prepared. Structure, isopach and formation lithology maps have been constructed, and burial history, thermal maturation history, and hydrocarbon expulsion profiles have been prepared. Seismic data, cross sections, subsurface maps and burial history, thermal maturation history, and hydrocarbon expulsion profiles have been used in evaluating the tectonic, depositional, burial and thermal maturation histories of the basin. Oil and gas reservoirs have been found to be associated with salt-supported anticlinal and domal features (salt pillows, turtle structures and piercement domes); with normal faulting associated with the northern basin margin and listric down-to-the-basin faults (state-line fault complex) and faulted salt features; and with combination structural and stratigraphic features (Sabine and Monroe Uplifts) and monoclinal features with lithologic variations. Petroleum reservoirs include Upper Jurassic and Cretaceous fluvial-deltaic sandstone facies; shoreline, marine bar and shallow shelf sandstone facies; and carbonate shoal, shelf and reef facies. Cretaceous unconformities significantly contribute to the hydrocarbon trapping mechanism capacity in the North Louisiana Salt Basin. The chief petroleum source rock in this basin is Upper Jurassic Smackover lime mudstone beds. The generation of hydrocarbons from Smackover lime mudstone was initiated during the Early Cretaceous and continued into the Tertiary. Hydrocarbon
Analysis of temporal and spatial trends of hydro-climatic variables in the Wei River Basin.
Zhao, Jing; Huang, Qiang; Chang, Jianxia; Liu, Dengfeng; Huang, Shengzhi; Shi, Xiaoyu
2015-05-01
The Wei River is the largest tributary of the Yellow River in China. The relationship between runoff and precipitation in the Wei River Basin has been changed due to the changing climate and increasingly intensified human activities. In this paper, we determine abrupt changes in hydro-climatic variables and identify the main driving factors for the changes in the Wei River Basin. The nature of the changes is analysed based on data collected at twenty-one weather stations and five hydrological stations in the period of 1960-2010. The sequential Mann-Kendall test analysis is used to capture temporal trends and abrupt changes in the five sub-catchments of the Wei River Basin. A non-parametric trend test at the basin scale for annual data shows a decreasing trend of precipitation and runoff over the past fifty-one years. The temperature exhibits an increase trend in the entire period. The potential evaporation was calculated based on the Penman-Monteith equation, presenting an increasing trend of evaporation since 1990. The stations with a significant decreasing trend in annual runoff mainly are located in the west of the Wei River primarily interfered by human activities. Regression analysis indicates that human activity was possibly the main cause of the decline of runoff after 1970. PMID:25619963
Numerical analysis of EPR spectra. 7. The simplex algorithm
NASA Astrophysics Data System (ADS)
Beckwith, Athelstan L. J.; Brumby, Steven
The Simplex algorithm is well suited to the least-squares analysis of highly complex EPR spectra. The application of the algorithm to the analysis of the spectra of benzo[ a]pyrenyl-6-oxy, chloro(methoxycarbonyl)methyl, and cyano(methoxy)methyl free radicals is described.
Numerical analysis and experimental research of the rubber boot of the joint drive vehicle
NASA Astrophysics Data System (ADS)
Ziobro, Jan
2016-04-01
The article presents many numerical studies and experimental research of the drive rubber boot of the joint drive vehicle. Performance requirements have been discussed and the required coefficients of the mathematical model for numerical simulation have been determined. The behavior of living in MSC.MARC environment was examined. In the analysis the following have been used: hyperplastic two-parameter model of the Mooney-Rivlin material, large displacements procedure, safe contact condition, friction on the sides of the boots. 3D numerical model of the joint bootwas analyzed under influence of the forces: tensile, compressive, centrifugal and angular. Numerous results of studies have been presented. An appropriate test stand was built and comparison of the results of the numerical analysis and the results of experimental studies was made. Numerous requests and recommendations for utilitarian character have been presented.
Numerical analysis of kinematic soil-pile interaction
Castelli, Francesco; Maugeri, Michele; Mylonakis, George
2008-07-08
In the present study, the response of singles pile to kinematic seismic loading is investigated using the computer program SAP2000. The objectives of the study are: (1) to develop a numerical model that can realistically simulate kinematic soil-structure interaction for piles accounting for discontinuity conditions at the pile-soil interface, energy dissipation and wave propagation; (2) to use the model for evaluating kinematic interaction effects on pile response as function of input ground motion; and (3) to present a case study in which theoretical predictions are compared with results obtained from other formulations. To evaluate the effects of kinematic loading, the responses of both the free-field soil (with no piles) and the pile were compared. Time history and static pushover analyses were conducted to estimate the displacement and kinematic pile bending under seismic loadings.
Numerical analysis of turbulent coaxial flow with internal heat generation
NASA Technical Reports Server (NTRS)
Lin, A.; Weinstein, H.
1981-01-01
A computational method with which to obtain a physical understanding of the turbulent field of two coaxial jets entering an axisymmetric chamber is developed. Even the laminar field of this flow is quite complicated. This is due to the many different domains which exist in the field especially in the entrance region. Physically, three regions may be identified: the wall region, the initial region near the axis of symmetry and the mixing region. Advancing downstream, these regions change relative size with the ratio of the two jets' mass fluxes as the main parameter. The turbulent field of these flows is much more complicated due to the difference in the effective transport coefficients and turbulence level from region to region. However, being aware beforehand of the complications and the different regions of this field, the appropriate turbulence model and numerical scheme can be adjusted to treat the problem.
Experimental and Numerical Analysis of Structural Acousticcontrol Interior Noise Reduction
NASA Technical Reports Server (NTRS)
Mei, Chuh; Bevan, Jeffrey S.
1999-01-01
The research results contained in this technical report were performed under the NASA grant entitled "Experimental and Numerical Structural Acoustic Control for Interior Noise Reduction". The report is based essentially on partial progress of the Ph.D. dissertation prepared by Jeffrey S. Bevan under direct guidance of Dr. Chuh Mei. The document presents a finite element formulation and control of sound radiated from cylindrical panels embedded with piezoceramic actuators. The extended MIN6 shallow shell element is fully electrical-structural coupled. A piezoelectric modal actuator participation (PMAP) is defined which indicates the actuator performance to each of the offending modes. Genetic algorithm is also employed to validate the sensor and actuator locations determined by the PMAP criteria. The work was conducted at the Department of Aerospace Engineering, Old Dominion University. Mr. Travis L. Turner, Structural Acoustics Branch, NASA Langley Research Center is the technical monitor.
Analysis of free turbulent shear flows by numerical methods
NASA Technical Reports Server (NTRS)
Korst, H. H.; Chow, W. L.; Hurt, R. F.; White, R. A.; Addy, A. L.
1973-01-01
Studies are described in which the effort was essentially directed to classes of problems where the phenomenologically interpreted effective transport coefficients could be absorbed by, and subsequently extracted from (by comparison with experimental data), appropriate coordinate transformations. The transformed system of differential equations could then be solved without further specifications or assumptions by numerical integration procedures. An attempt was made to delineate different regimes for which specific eddy viscosity models could be formulated. In particular, this would account for the carryover of turbulence from attached boundary layers, the transitory adjustment, and the asymptotic behavior of initially disturbed mixing regions. Such models were subsequently used in seeking solutions for the prescribed two-dimensional test cases, yielding a better insight into overall aspects of the exchange mechanisms.
Numerical analysis of kinematic soil—pile interaction
NASA Astrophysics Data System (ADS)
Castelli, Francesco; Maugeri, Michele; Mylonakis, George
2008-07-01
In the present study, the response of singles pile to kinematic seismic loading is investigated using the computer program SAP2000@. The objectives of the study are: (1) to develop a numerical model that can realistically simulate kinematic soil-structure interaction for piles accounting for discontinuity conditions at the pile-soil interface, energy dissipation and wave propagation; (2) to use the model for evaluating kinematic interaction effects on pile response as function of input ground motion; and (3) to present a case study in which theoretical predictions are compared with results obtained from other formulations. To evaluate the effects of kinematic loading, the responses of both the free-field soil (with no piles) and the pile were compared. Time history and static pushover analyses were conducted to estimate the displacement and kinematic pile bending under seismic loadings.
Upward movement of tritium from contaminated groundwaters: a numerical analysis.
Belot, Y; Watkins, B M; Edlund, O; Galeriu, D; Guinois, G; Golubev, A V; Meurville, C; Raskob, W; Täschner, M; Yamazawa, H
2005-01-01
This paper describes a research-oriented modelling exercise that addresses the problem of assessing the movement of tritium from a contaminated perched aquifer to the land surface. Participants were provided with information on water table depth, soil characteristics, hourly meteorological and evapotranspiration data. They were asked to predict the upward migration of tritium through the unsaturated soil into the atmosphere. Eight different numerical models were used to calculate the movement of tritium. The modelling results agree within a factor of two, if very small time and space increments are used. The agreement is not so good when the near-surface soil becomes dry. The modelling of the alternate upward and downward transport of tritium close to the ground surface generally requires rather complex models and detailed input because tritium concentration varies sharply over short distances and is very sensitive to many interactive factors including rainfall amount, evapotranspiration rate, rooting depth and water table position. PMID:15990205
Numerical analysis of internal waves in stratified wake flows
NASA Astrophysics Data System (ADS)
Fraunie, Philppe
2014-05-01
In laboratory investigations, increased attention has been given to internal waves generated by stationary placed oscillating sources and moving bodies in stratified fluids [1]. The main attention was paid to study flows past bodies of perfect shapes like sphere [2], cylinder [3] of thin strip [3] which are the best theoretical (analytical or numerical) studies. Due to simplicity of geometry, flow around a strip has a potential to investigate separately effects of a drag and lift forces on the body by changing the slope of the horizontally moving strip which can be placed vertically [1], horizontally [2], or be tilted under some angle to the direction of towing velocity [5]. Numeric modeling of a flow past vertical strip uniformly towing with permanent velocity in horizontal direction in a linearly stratified talk which was based on a finite differences solver adapted to the low Reynolds Navier-Stokes equation with transport equation for salinity (LES simulation [6] and RANS [7]) has demonstrated reasonable agreement with data of Schlieren visualization, density marker and probe measurements of internal wave fields. The chosen test cases allowed demonstrating the ability of selected numerical methods to represent stably stratified flows over horizontal strip [4] and hill type 2D obstacles [1, 3] with generation of internal waves. ACKNOWLEDGMENTS This research work was supported by the Region Provence Alpes Côte d'Azur - Modtercom project. The work was also supported by the Russian Foundation for Basic Research (grant 12-01-00128). REFERENCES [1] Chashechkin Yu.D., Mitkin V.V. Experimental study of a fine structure of 2D wakes and mixing past an obstacle in a continuously stratified fluid // Dynamics of Atmosphere and Oceans. 2001. V. 34. P. 165-187. [2] Chashechkin, Yu. D. Hydrodynamics of a sphere in a stratified fluid // Fluid Dyn. 1989. V.24(1) P. 1-7. [3] Mitkin V. V., Chashechkin Yu. D. Transformation of hanging discontinuities into vortex systems in a
Time Series Analysis for the Drac River Basin (france)
NASA Astrophysics Data System (ADS)
Parra-Castro, K.; Donado-Garzon, L. D.; Rodriguez, E.
2013-12-01
This research is based on analyzing of discharge time-series in four stream flow gage stations located in the Drac River basin in France: (i) Guinguette Naturelle, (ii) Infernet, (iii) Parassat and the stream flow gage (iv) Villard Loubière. In addition, time-series models as the linear regression (single and multiple) and the MORDOR model were implemented to analyze the behavior the Drac River from year 1969 until year 2010. Twelve different models were implemented to assess the daily and monthly discharge time-series for the four flow gage stations. Moreover, five selection criteria were use to analyze the models: average division, variance division, the coefficient R2, Kling-Gupta Efficiency (KGE) and the Nash Number. The selection of the models was made to have the strongest models with an important level confidence. In this case, according to the best correlation between the time-series of stream flow gage stations and the best fitting models. Four of the twelve models were selected: two models for the stream flow gage station Guinguette Naturel, one for the station Infernet and one model for the station Villard Loubière. The R2 coefficients achieved were 0.87, 0.95, 0.85 and 0.87 respectively. Consequently, both confidence levels (the modeled and the empirical) were tested in the selected model, leading to the best fitting of both discharge time-series and models with the empirical confidence interval. Additionally, a procedure for validation of the models was conducted using the data for the year 2011, where extreme hydrologic and changes in hydrologic regimes events were identified. Furthermore, two different forms of estimating uncertainty through the use of confidence levels were studied: the modeled and the empirical confidence levels. This research was useful to update the used procedures and validate time-series in the four stream flow gage stations for the use of the company Électricité de France. Additionally, coefficients for both the models and
NASA Astrophysics Data System (ADS)
Boesche, N.; Trauth, M.
2012-04-01
Provenance analysis is an essential discipline for describing the generation and dispersal of sediments and yields a fundamental understanding of hydrological and sedimentological processes. Chew Bahir basin is a hardly accessible terrain in southern Ethiopia, which is barely investigated by sedimentological studies until today. In this work, those studies were conducted via remotely sensed digital image analysis (ASTER, Landsat ETM+, Worldview-1 and SRTM) combined with a climatological approach through precipitation data from the Tropical Rainfall Measuring Mission (TRMM). Besides remote sensing, sedimentological investigations were achieved from a highly resolved paleo-climate record through a short drill-core from Chew Bahir basin. In order to identify and localize potential source areas and to describe the dispersal of sediments, different processing methodologies were applied (achievement of sediment composition, land-surface classification, digital terrain analysis and generation of remote sensing time series). The result of this work demonstrates two different source rocks, which belong to two distinct source localities. Hence, the analysis of remote sensed digital imaginary provides an effective tool for studying the provenance of sediments, especially in remote regions such as Chew Bahir basin. Moreover, remotely sensed time series provide important insights into climatologically induced variations in the uppermost sediment-layer. However, fully automated analysis of remotely sensed imaginary cannot replace fieldwork, but provides outstanding contributions to interdisciplinarity.
Ernest A. Mancini; Donald A. Goddard; Ronald K. Zimmerman
2005-05-10
The principal research effort for Year 2 of the project has been data compilation and the determination of the burial and thermal maturation histories of the North Louisiana Salt Basin and basin modeling and petroleum system identification. In the first nine (9) months of Year 2, the research focus was on the determination of the burial and thermal maturation histories, and during the remainder of the year the emphasis has basin modeling and petroleum system identification. Existing information on the North Louisiana Salt Basin has been evaluated, an electronic database has been developed, regional cross sections have been prepared, structure and isopach maps have been constructed, and burial history, thermal maturation history and hydrocarbon expulsion profiles have been prepared. Seismic data, cross sections, subsurface maps and related profiles have been used in evaluating the tectonic, depositional, burial and thermal maturation histories of the basin. Oil and gas reservoirs have been found to be associated with salt-supported anticlinal and domal features (salt pillows, turtle structures and piercement domes); with normal faulting associated with the northern basin margin and listric down-to-the-basin faults (state-line fault complex) and faulted salt features; and with combination structural and stratigraphic features (Sabine and Monroe Uplifts) and monoclinal features with lithologic variations. Petroleum reservoirs are mainly Upper Jurassic and Lower Cretaceous fluvial-deltaic sandstone facies and Lower Cretaceous and Upper Cretaceous shoreline, marine bar and shallow shelf sandstone facies. Cretaceous unconformities significantly contribute to the hydrocarbon trapping mechanism capacity in the North Louisiana Salt Basin. The chief petroleum source rock in this basin is Upper Jurassic Smackover lime mudstone beds. The generation of hydrocarbons from Smackover lime mudstone was initiated during the Early Cretaceous and continued into the Tertiary
NASA Astrophysics Data System (ADS)
Lee, Sang-Mook; Kim, Yoon-Mi
2016-04-01
Marginal basins locate between the continent and arc islands often exhibit diverse style of opening, from regions that appear to have formed by well-defined and localized spreading center (manifested by the presence of distinct seafloor magnetic anomaly patterns) to those with less obvious zones of extension and a broad magmatic emplacement most likely in the lower crust. Such difference in the style of back-arc basin formation may lead to marked difference in crustal structure in terms of its overall thickness and spatial variations. The Ulleung Basin, one of three major basins in the East Sea/Sea of Japan, is considered to represent a continental rifting end-member of back-arc opening. Although a great deal of work has been conducted on the sedimentary sections in the last several decades, the deep crustal sections have not been systematically investigated for long time, and thus the structure and characteristics of the crust remain poorly understood. This study examines the marine gravity anomalies of the Ulleung Basin in order to understand the crustal structure using crucial sediment-thickness information. Our analysis shows that the Moho depth in general varies from 16 km at the basin center to 22 km at the margins. However, within the basin center, the inferred thickness of the crust is more or less the same (10-12 km), thus by varying only about 10-20% of the total thickness, contrary to the previous impression. The almost-uniformly-thick crust that is thicker than a normal oceanic crust (~ 7 km) is consistent with previous observations using ocean bottom seismometers and recent deep seismic results from the nearby Yamato Basin. Another important finding is that small residual mantle gravity anomaly highs exist in the northern part of the basin. These highs are aligned in the NNE-SSW direction which correspond to the orientation of the major tectonic structures on the Korean Peninsula, raising the possibility that, though by a small degree, they are a
Minimizing Errors in Numerical Analysis of Chemical Data.
ERIC Educational Resources Information Center
Rusling, James F.
1988-01-01
Investigates minimizing errors in computational methods commonly used in chemistry. Provides a series of examples illustrating the propagation of errors, finite difference methods, and nonlinear regression analysis. Includes illustrations to explain these concepts. (MVL)
Ernest A. Mancini
2005-03-31
The principal research effort for Year 2 of the project is the determination of the burial and thermal maturation histories and basin modeling and petroleum system identification of the North Louisiana Salt Basin. In the first six (6) to nine (9) months of Year 2, the research focus is on the determination of the burial and thermal maturation histories and the remainder of the year the emphasis is on basin modeling and petroleum system identification. No major problems have been encountered to date, and the project is on schedule.
Ernest A. Mancini
2004-11-05
The principal research effort for Year 2 of the project is the determination of the burial and thermal maturation histories and basin modeling and petroleum system identification of the North Louisiana Salt Basin. In the first six (6) to nine (9) months of Year 2, the research focus is on the determination of the burial and thermal maturation histories and the remainder of the year the emphasis is on basin modeling and petroleum system identification. No major problems have been encountered to date, and the project is on schedule.
Graphic analysis of resources by numerical evaluation techniques (Garnet)
Olson, A.C.
1977-01-01
An interactive computer program for graphical analysis has been developed by the U.S. Geological Survey. The program embodies five goals, (1) economical use of computer resources, (2) simplicity for user applications, (3) interactive on-line use, (4) minimal core requirements, and (5) portability. It is designed to aid (1) the rapid analysis of point-located data, (2) structural mapping, and (3) estimation of area resources. ?? 1977.
A general numerical analysis program for the superconducting quasiparticle mixer
NASA Technical Reports Server (NTRS)
Hicks, R. G.; Feldman, M. J.; Kerr, A. R.
1986-01-01
A user-oriented computer program SISCAP (SIS Computer Analysis Program) for analyzing SIS mixers is described. The program allows arbitrary impedance terminations to be specified at all LO harmonics and sideband frequencies. It is therefore able to treat a much more general class of SIS mixers than the widely used three-frequency analysis, for which the harmonics are assumed to be short-circuited. An additional program, GETCHI, provides the necessary input data to program SISCAP. The SISCAP program performs a nonlinear analysis to determine the SIS junction voltage waveform produced by the local oscillator. The quantum theory of mixing is used in its most general form, treating the large signal properties of the mixer in the time domain. A small signal linear analysis is then used to find the conversion loss and port impedances. The noise analysis includes thermal noise from the termination resistances and shot noise from the periodic LO current. Quantum noise is not considered. Many aspects of the program have been adequately verified and found accurate.
NASA Astrophysics Data System (ADS)
Goggin, Valerie; Jacquin, Thierry; Gaulier, Jean Michel
1997-12-01
The mechanisms governing the development of the Paris Basin throughout the Triassic are regarded as being the result of superimposed and successive processes. In this study, the Triassic succession of the Paris Basin was re-interpreted in a sequence stratigraphic context, using essentially wireline log data. From this, a series of isopach maps, lithofacies maps and palaeobathymetric maps was produced for each sequence. Three-dimensional accommodation analysis was then carried out sequence by sequence, over the entire basin to produce a precise, detailed accommodation history for the entire Triassic succession. Previous studies have proposed that the Triassic was deposited during a rift period in a transtensional stress regime, with the formation of a trough superposed onto three fault systems derived from the Variscan structural framework. In this study, Scythian to Ladinian sediments (Buntsandstein and Muschelkalk) record the stress regime that prevailed over much of NW Europe. The basin architecture at this time is in continuity with the neighbouring Germanic Basin. Our three-dimensional accommodation modelling shows that the stress regime changed during the Carnian and the late Norian (Keuper). The Carnian events are marked by (1) the creation of a large depocentre infilled with halite, and (2) a northwest migration of this depocentre during the mid-late Carnian along with deposition of the Grès-à-Roseaux, an extensive fluvial deposit. This documents renewed strike-slip movement along the Bray fault. The Norian events involved major tectonic uplift on the basin margins, producting fan delta progradation into the basin. Rotation of the previous depocentre axis occurs on the downthrown side of the Bray fault. This may be viewed as a consequence of sinistral strike-slip displacement along the Bray fault, forming a local transpressive stress regime. The following Liassic cycle commenced with the Rhaetic sequences and illustrates a complete change in the stress
Numerical methods for the design and analysis of wings at supersonic speeds
NASA Technical Reports Server (NTRS)
Carlson, H. W.; Miller, D. S.
1974-01-01
Numerical methods for the design and analysis of arbitrary-planform wings at supersonic speeds are reviewed. Certain deficiencies are revealed, particularly in application to wings with slightly subsonic leading edges. Recently devised numerical techniques which overcome the major part of these deficiencies are presented. The original development as well as the more recent revisions are subjected to a thorough review.
Temporal precipitation trend analysis at the Langat River Basin, Selangor, Malaysia
NASA Astrophysics Data System (ADS)
Palizdan, Narges; Falamarzi, Yashar; Huang, Yuk Feng; Lee, Teang Shui; Ghazali, Abdul Halim
2015-12-01
The Langat River Basin provides fresh water for about 1.2 million people in the Langat and Klang valleys. Any change in the pattern of rainfall could affect the quantity of water in the basin. Studying the pattern of change in rainfall is crucial for managing the available water resources in the basin. Thus, in this study, for the first time, both parametric and non-parametric methods were employed to detect rainfall trend in the basin for the period 1982-2011. The trends were determined at 30 rainfall stations using the Mann-Kendall (MK) test, the Sen's slope estimator and the linear regression analysis. Lag-1 approach was utilized to test the serial correlation of the series. On the annual scale, it was found that most of the stations in the basin were characterized with insignificant trends. The significant trends were found only at the four stations, namely 44301, 44305, 44320 and 2719001. The results of the seasonal trend analysis showed that most of the stations during the northeast monsoon (NEM) and the inter monsoon 1 (INT1) seasons and half of the stations during the southwest monsoon (SWM) season experienced insignificant positive trends. To the contrary, for the inter monsoon 2 (INT2) season, majority of the stations showed negative trends. It was found that during the NEM season the station 44301, for the INT1 season stations 44301, 2719001 and 3118069 were established as having significant changes, while in the SWM season station 2917001 and during the INT2 season, the stations 2615131 and 44301 showed significant trends. It is worth mentioning that the maximum rainfall occurs in inter-monsoon seasons.
Surface plasmon resonance sensor based on spectral interferometry: numerical analysis.
Zhang, Yunfang; Li, Hui; Duan, Jingyuan; Shi, Ancun; Liu, Yuliang
2013-05-10
In this paper, we introduce a numerical simulation of a phase detecting surface plasmon resonance (SPR) scheme based on spectral interference. Based on the simulation, we propose a method to optimize various aspects of SPR sensors, which enables better performance in both measurement range (MR) and sensitivity. In the simulation, four parameters including the spectrum of the broadband light source, incident angle, Au film thickness, and refractive index of the prism coupler are analyzed. The results show that it is a good solution for better performance to use a warm white broadband (625-800 nm) light source, a divergence angle of the collimated incident light less than 0.02°, and an optimized 48 nm thick Au film when a visible broadband light source is used. If a near-IR light source is used, however, the Au film thickness should be somewhat thinner according the specific spectrum. In addition, a wider MR could be obtained if a prism coupler with higher refractive index is used. With all the parameters appropriately set, the SPR MR could be extended to 0.55 refractive index units while keeping the sensitivity at a level of 10(-8). PMID:23669838
A Hybrid Numerical Analysis Method for Structural Health Monitoring
NASA Technical Reports Server (NTRS)
Forth, Scott C.; Staroselsky, Alexander
2001-01-01
A new hybrid surface-integral-finite-element numerical scheme has been developed to model a three-dimensional crack propagating through a thin, multi-layered coating. The finite element method was used to model the physical state of the coating (far field), and the surface integral method was used to model the fatigue crack growth. The two formulations are coupled through the need to satisfy boundary conditions on the crack surface and the external boundary. The coupling is sufficiently weak that the surface integral mesh of the crack surface and the finite element mesh of the uncracked volume can be set up independently. Thus when modeling crack growth, the finite element mesh can remain fixed for the duration of the simulation as the crack mesh is advanced. This method was implemented to evaluate the feasibility of fabricating a structural health monitoring system for real-time detection of surface cracks propagating in engine components. In this work, the authors formulate the hybrid surface-integral-finite-element method and discuss the mechanical issues of implementing a structural health monitoring system in an aircraft engine environment.
Containment steam blowdown analysis : experimental and numerical comparisons.
NguyenLe, Q.; Ishii, M.; Reactor Analysis; Purdue Univ.
1999-01-01
This paper compares the numerical simulation with the experimental data of a steam blowdown event in a light water reactor containment building. A three step approach was used to analyze the steam jet behavior. First, the temperature and pressure data of a steam blowdown event was measured at the Purdue University Multi-Dimensional Integrated Test Assembly (PUMA), a scaled model of the General Electric Simplified Boiling Water Reactor. Second, a 1-dimensonial, system level RELAP5/Mod3.2 model of the steam blowdown event was created and the results used to set the initial conditions for the PUMA blowdown experiments. Finally, 2-dimensional and 3-dimensional CFD models of the discharged steam jets were computed using PHOENICS, a commercially available CFD package. It was found that RELAP5 is reasonably capable in predicting the general temperature and pressure trends in the RPV. However, due to modeling compromises and the code's built-in capabilities, RELAP5 1-dimensional predictions of containment temperature and pressure did not compare well with measured data. On the other hand, with minor modfications to the k-{var_epsilon} turbulence model, the 2-dimensional and 3-dimensional PHOENICS CFD solutions compared extremely well with the measured data.
Interaction of debris with a solid obstacle: numerical analysis.
Kosinska, Anna
2010-05-15
The subject of this research is the propagation of a cloud of solid particles formed from an explosion-damaged construction. The main objective is the interaction of the cloud (debris) with a solid beam located at some distance from the explosion. The mathematical model involves the flow of the gas using standard conservation equations, and this part of the model is solved numerically. The solid particles are treated as a system of solid points (so-called Lagrangian approach), whose motion is the result of the flowing gas as well as collisions with obstacles. These two issues are described respectively by Newton's second law and the hard-sphere model. The model is used to simulate various cases where the influence of different parameters like the value of the pressure of the explosion, the particle size, the number of particles and the obstacle location are investigated. The results are presented as snapshots of particle location, and also as the particle total momentum during collision with the beam. PMID:20060218
Numerical Analysis Of Three Component Induction Logging In Geothermal Reservoirs
Dr. David L. Alumbaugh
2002-01-09
This project is supporting the development of the ''Geo-Bilt'', geothermal electromagnetic-induction logging tool that is being built by ElectroManetic Instruments, Inc. The tool consists of three mutually orthogonal magnetic field antennas, and three-component magnetic field receivers located at different distances from the source. In its current configuration, the source that has a moment aligned along the borehole axis consists of a 1m long solenoid, while the two trans-axial sources consist of 1m by 8cm loops of wire. The receivers are located 2m and 5m away from the center of the sources, and five frequencies from 2 kHz to 40 kHz are being employed. This study is numerically investigating (1) the effect of the borehole on the measurements, and (2) the sensitivity of the tool to fracture zone-geometries that might be encountered in a geothermal field. The benefits of the results are that they will lead to a better understanding of the data that the tool produces during its testing phase and an idea of what the limitations of the tool are.
Numerical Analysis of a Radiant Heat Flux Calibration System
NASA Technical Reports Server (NTRS)
Jiang, Shanjuan; Horn, Thomas J.; Dhir, V. K.
1998-01-01
A radiant heat flux gage calibration system exists in the Flight Loads Laboratory at NASA's Dryden Flight Research Center. This calibration system must be well understood if the heat flux gages calibrated in it are to provide useful data during radiant heating ground tests or flight tests of high speed aerospace vehicles. A part of the calibration system characterization process is to develop a numerical model of the flat plate heater element and heat flux gage, which will help identify errors due to convection, heater element erosion, and other factors. A 2-dimensional mathematical model of the gage-plate system has been developed to simulate the combined problem involving convection, radiation and mass loss by chemical reaction. A fourth order finite difference scheme is used to solve the steady state governing equations and determine the temperature distribution in the gage and plate, incident heat flux on the gage face, and flat plate erosion. Initial gage heat flux predictions from the model are found to be within 17% of experimental results.
Numerical analysis of dipole sound source around high speed trains.
Takaishi, Takehisa; Sagawa, Akio; Nagakura, Kiyoshi; Maeda, Tatsuo
2002-06-01
As the maximum speed of high speed trains increases, the effect of aeroacoustic noise on the sound level on the ground becomes increasingly important. In this paper, the distribution of dipole sound sources at the bogie section of high speed trains is predicted numerically. The three-dimensional unsteady flow around a train is solved by the large eddy simulation technique. The time history of vortices shows that unstable shear layer separation at the leading edge of the bogie section sheds vortices periodically. These vortices travel downstream while growing to finally impinge upon the trailing edge of the section. The wavelength of sound produced by these vortices is large compared to the representative length of the bogie section, so that the source region can be regarded as acoustically compact. Thus a compact Green's function adapted to the shape can be used to determine the sound. By coupling the instantaneous flow properties with the compact Green's function, the distribution of dipole sources is obtained. The results reveal a strong dipole source at the trailing edge of the bogie section where the shape changes greatly and the variation of flow with time is also great. On the other hand, the bottom of the bogie section where the shape does not change, or the leading edge and boundary layer where the variation of flow with time is small, cannot generate a strong dipole source. PMID:12083191
Numerical analysis of dipole sound source around high speed trains
NASA Astrophysics Data System (ADS)
Takaishi, Takehisa; Sagawa, Akio; Nagakura, Kiyoshi; Maeda, Tatsuo
2002-06-01
As the maximum speed of high speed trains increases, the effect of aeroacoustic noise on the sound level on the ground becomes increasingly important. In this paper, the distribution of dipole sound sources at the bogie section of high speed trains is predicted numerically. The three-dimensional unsteady flow around a train is solved by the large eddy simulation technique. The time history of vortices shows that unstable shear layer separation at the leading edge of the bogie section sheds vortices periodically. These vortices travel downstream while growing to finally impinge upon the trailing edge of the section. The wavelength of sound produced by these vortices is large compared to the representative length of the bogie section, so that the source region can be regarded as acoustically compact. Thus a compact Green's function adapted to the shape can be used to determine the sound. By coupling the instantaneous flow properties with the compact Green's function, the distribution of dipole sources is obtained. The results reveal a strong dipole source at the trailing edge of the bogie section where the shape changes greatly and the variation of flow with time is also great. On the other hand, the bottom of the bogie section where the shape does not change, or the leading edge and boundary layer where the variation of flow with time is small, cannot generate a strong dipole source. copyright 2002 Acoustical Society of America.
Numerical analysis for cavitation flow of marine propeller
NASA Astrophysics Data System (ADS)
Tauviqirrahman, Mohammad; Muchammad, Ismail, Rifky; Jamari, J.
2015-12-01
Concerning the environmental issue and the increase of fuel price, optimizing the fuel consumption has been recently an important subject in all industries. In marine industries one of the ways to decrease the energy consumption was by reducing the presence of cavitation on marine propeller blades. This will give a higher propulsive efficiency. This paper provides an investigation into the influence of the cavitation on a hydrodynamic performance around the propeller based on numerical method. Hydrofoil representing the blade form of propeller was of particular of interest. Two types of cavitation model were investigated with respect to the accuracy of the result and the effectiveness of the method. The results include the hydrodynamic characteristics of cavitation phenomenon like lift/drag variation with respect to the cavity extent. It was found that a high accuracy and low computational time is achieved when the cavitation model of Zwart-Gerber-Belamri is used. The interesting outcome of this study is that the results can be used as a good evaluation tool for high marine propeller performance.
Numerical Analysis of Thermal Comfort at Urban Environment
NASA Astrophysics Data System (ADS)
Papakonstantinou, K.; Belias, C.
2009-08-01
The present paper refers to the numerical simulation of air velocity at open air spaces and the conducting thermal comfort after the evaluation of the examined space using CFD methods, taking into account bioclimatic principles at the architectural design. More specially, the paper draws attention to the physical procedures governing air movement at an open environment area in Athens (athletic park), named "Serafeio Athletic and Cultural Centre," trying to form them in such way that will lead to the thermal comfort of the area's visitors. The study presents a mathematical model, implemented in a general computer code that can provide detailed information on velocity, prevailing in three-dimensional spaces of any geometrical complexity. Turbulent flow is simulated and buoyancy effects are taken into account. This modelling procedure is intended to contribute to the effort towards designing open areas, such as parks, squares or outdoor building environments, using thermal comfort criteria at the bioclimatic design. A computer model of this kind will provide the architects or the environmental engineers with powerful and economical means of evaluating alternative spaces' designs.
Numerical Analysis of Thermal Comfort at Open Air Spaces
NASA Astrophysics Data System (ADS)
Papakonstantinou, K.; Belias, C.; Pantos-Kikkos, S.; Assana, A.
2008-09-01
The present paper refers to the numerical simulation of air velocity at open air spaces and the conducting thermal comfort after the evaluation of the examined space using CFD methods, taking into account bioclimatic principles at the architectural design. More specially, the paper draws attention to the physical procedures governing air movement at an open environment area in Athens (urban park), named "Attiko Alsos," trying to form them in such way that will lead to the thermal comfort of the area's visitors. The study presents a mathematical model, implemented in a general computer code that can provide detailed information on velocity, prevailing in three-dimensional spaces of any geometrical complexity. Turbulent flow is simulated and buoyancy effects are taken into account. This modelling procedure is intended to contribute to the effort towards designing open areas, such as parks, squares or outdoor building environments, using thermal comfort criteria at the bioclimatic design. A computer model of this kind will provide the architects or the environmental engineers with powerful and economical means of evaluating alternative spaces' designs.
Numerical analysis of the ultraprecision machining of copper
Stevens, R.; Anderson, C.; Rhorer, R.; Lucca, D.
1995-03-01
Modeling of the ultraprecision machining process can aid in the understanding of the relative importance of various process parameters and ultimately lead to improved methods of generating ultraprecision surfaces such as those required for metal optics and single crystal microelectronics substrates. Any modeling method should be verified by direct comparison to experimental data. Until recently it has been difficult to accurately measure the cutting edge, or sharpness, of a diamond tool; and therefore, most models have assumed an infinitely sharp cutting tip. With the relatively new technology of the Atomic Force Microscope (AFM), the cutting edge of single crystal diamond tools can be quantitatively described. Ultraprecision machining experiments using an AFM characterized cutting tool and orthogonal geometry have been performed. These experiments have resulted in measured cutting and thrust forces for different depths of cut in copper (Te-Cu: 99.4-99.5% Cu, 0.5-0.6% Te, 4-5 micron grain size, 225 MPa yield strength) with a well characterized diamond tool. By using this actual tool tip geometry the authors have been able to develop a model that can predict cutting and thrust forces for depths of cut on the order of the sharpness of the tool. Forces predicted by this numerical model are compared to the experimentally measured forces.
Numerical analysis of hemodynamics in spastic middle cerebral arteries.
Wen, Jun; Wang, Qingfeng; Wang, Qingyuan; Khoshmanesh, Khashayar; Zheng, Tinghui
2016-11-01
Cerebral vasospasm (CVS) is the most common serious complication of subarachnoid hemorrhage. Among the many factors that are associated with the pathogenesis of CVS, hemodynamics plays an important role in the initiation and development of CVS. Numerical simulation was carried out to obtain the flow patterns and wall shear stress (WSS) distribution in spastic middle cerebral arteries. The blood was assumed to be incompressible, laminar, homogenous, Newtonian, and steady. Our simulations reveal that flow velocity and WSS level increase at the stenosis segment of the spastic vessels, but further downstream of stenosis, the WSS significantly decreases along the inner wall, and flow circulation and stagnation are observed. The hydrodynamic resistance increases with the increase of vessel spasm. Moreover, the change of flow field and hydrodynamic forces are not linearly proportional to the spasm level, and the rapid change of hemodynamic parameters is observed as the spasm is more than 50%. Accordingly, in the view of hemodynamic physiology, vessels with less than 30% stenosis are capable of self-restoration towards normal conditions. However, vessels with more than 50% stenosis may eventually lose their capacity to adapt to differing physiologic conditions due to the extreme non-physilogic hemodynamic environment, and the immediate expansion of the vessel lumen might be needed to minimize serious and non-reversible effects. PMID:26942314
A numerical model for dynamic wave rotor analysis
NASA Technical Reports Server (NTRS)
Paxson, D. E.
1995-01-01
A numerical model has been developed which can predict the dynamic (and steady state) performance of a wave rotor, given the geometry and time dependent boundary conditions. The one-dimensional, perfect gas, CFD based code tracks the gasdynamics in each of the wave rotor passages as they rotate past the various ducts. The model can operate both on and off-design, allowing dynamic behavior to be studied throughout the operating range of the wave rotor. The model accounts for several major loss mechanisms including finite passage opening time, fluid friction, heat transfer to and from the passage walls, and leakage to and from the passage ends. In addition, it can calculate the amount of work transferred to and from the fluid when the flow in the ducts is not aligned with the passages such as occurs in off-design operation. Since it is one-dimensional, the model runs reasonably fast on a typical workstation. This paper will describe the model and present the results of some transient calculations for a conceptual four port wave rotor designed as a topping cycle for a small gas turbine engine.
Numerical Analysis including Pressure Drop in Oscillating Water Column Device
NASA Astrophysics Data System (ADS)
das Neves Gomes, Mateus; Domingues dos Santos, Elizaldo; Isoldi, Liércio André; Rocha, Luiz Alberto Oliveira
2015-06-01
The wave energy conversion into electricity has been increasingly studied in the last years. There are several proposed converters. Among them, the oscillatingwater column (OWC) device has been widespread evaluated in literature. In this context, the main goal of this work was to perform a comparison between two kinds of physical constraints in the chimney of the OWC device, aiming to represent numerically the pressure drop imposed by the turbine on the air flow inside the OWC. To do so, the conservation equations of mass,momentumand one equation for the transport of volumetric fraction were solved with the finite volume method (FVM). To tackle thewater-air interaction, the multiphase model volume of fluid (VOF)was used. Initially, an asymmetric constraint inserted in chimney duct was reproduced and investigated. Subsequently, a second strategywas proposed,where a symmetric physical constraint with an elliptical shapewas analyzed. Itwas thus possible to establish a strategy to reproduce the pressure drop in OWC devices caused by the presence of the turbine, as well as to generate its characteristic curve.
Numerical analysis of electromagnetic cascades in emulsion chambers
NASA Technical Reports Server (NTRS)
Plyasheshnikov, A. V.; Vorobyev, K. V.
1985-01-01
A new calculational scheme of the Monte Carlo method assigned for the investigation of the development of high and extremely high energy electromagnetic cascades (EMC) in the matter was elaborated. The scheme was applied to the analysis of angular and radial distributions of EMC electrons in the atmosphere. By means of this scheme the EMC development in dense medium is investigated and some preliminary data are presented on the behavior of EMC in emulsion chambers. The results of more detailed theoretical analysis of the EMC development in emulsion chambers are discussed.
Numerical analysis of the Iosipescu specimen for composite materials
NASA Technical Reports Server (NTRS)
Ho, H.; Tsai, M. Y.; Morton, J.; Farley, G. L.
1993-01-01
A finite element analysis of the Iosipescu shear tests for unidirectional and cross-ply composites is presented. It is shown that an iterative analysis procedure must be used to model the fixture-specimen kinematics. The correction factors which are needed to compensate for the nonuniformity of stress distribution in calculating shear modulus are shown to be dependent on the material orthotropic ratio and the finite element loading models. Test section strain distributions representative of typical graphite-epoxy specimens are also presented.
Numerical analysis of the Iosipescu specimen for composite materials
NASA Technical Reports Server (NTRS)
Ho, H.; Tsai, M. Y.; Morton, J.; Farley, G. L.
1992-01-01
A finite element analysis of the Iosipescu shear tests for unidirectional and cross-ply composites is presented. It is shown that an iterative analysis procedure must be used to model the fixture-specimen kinematics. The correction factors which are needed to compensate for the nonuniformity of stress distribution in calculating shear modulus are shown to be dependent on the material orthotropic ratio and the finite element loading models. Test section strain distributions representative of typical graphite-epoxy specimens are also presented.
Ernest A. Mancini
2003-11-11
The principal research effort for Year 1 of the project is data compilation and the determination of the tectonic and depositional histories of the North Louisiana Salt Basin. In the first three (3) to six (6) months of Year 1, the research focus is on data compilation and the remainder of the year the emphasis is on the tectonic and depositional histories of the basin. No major problems have been encountered to date, and the project is on schedule.
Ernest A. Mancini
2003-09-11
The principal research effort for Year 1 of the project is data compilation and the determination of the tectonic and depositional histories of the North Louisiana Salt Basin. In the first three (3) to six (6) months of Year 1, the research focus is on data compilation and the remainder of the year the emphasis is on the tectonic and depositional histories of the basin. No major problems have been encountered to date, and the project is on schedule.
NASA Astrophysics Data System (ADS)
Cai, Ximing; McKinney, Daene C.; Lasdon, Leon S.
2002-06-01
Sustainable water management in irrigation-dominated river basins attempts to ensure a long-term, stable, and flexible water supply to meet crop water demands, as well as growing municipal and industrial water demands, while mitigating negative environmental consequences. To achieve this delicate balance, new models are needed which can use indicators of sustainability to guide the decision-making process. This paper presents a new long-term modeling framework which uses quantified sustainability criteria in a long-term optimization model of a basin, ensuring risk minimization in water supply, environmental conservation, equity in water allocation, and economic efficiency in water infrastructure development. ``Current'' and ``future'' water supply and demand are combined into a coherent system which takes account of the cumulative effects of short-term water use decisions and deals with the tradeoffs between the benefits of current and future generations. The modeling framework is demonstrated with an application to the Syr Darya River Basin of central Asia. Model results show the effectiveness of this tool for policy analysis in the context of the river basin.
An analysis of the coal-seam gas resource of the Piceance Basin, Colorado
McFall, K.S.; Wicks, D.E.; Kelso, B.S.; Brandenburg, C.F.
1988-06-01
A detailed geologic analysis of the Piceance basin in northwestern Colorado shows that nearly 84 Tcf (2.4 x 10/sup 12/ m/sup 3/) of coal-seam gas is in place in three target coal groups. The Cameo coal group contains the most coalbed methane with 65 Tcf (1.8 x 10/sup 12/ m/sup 3/). The more areally limited Coal Ridge and Black Diamond coal groups contain significantly less gas, 10 and 9 Tcf (280 x 10/sup 9/ and 255 x 10/sup 9/ m/sup 3/), respectively. The areas of highest methane concentration are in the east-central portion of the Piceance basin. These areas coincide with thick deposits of high-rank coal at significant depths and their associated higher gas contents. Also, these areas appear to have been structurally (tectonically) altered, leading to enhanced permeability to gas and water. Thus, the east-central basin area appears favorable for coalbed methane production. This study relied on extensive well data to correlate and map the subsurface extent of the Cretaceous coals of the Piceance basin. Newly derived correlations of coal-rank/depth with gas content were used along with estimates of coal volume to determine gas in place.
Basin Analysis - Richton Dome Area, Mississippi: annual status report for fiscal year 1982
Not Available
1983-06-01
Basin Analysis is an investigation of regional sedimentary and tectonic conditions in the Mississippi Salt Basin and their implications for the stability of Richton Dome. Approximately 7000 oil- and gas-well completion records were reviewed and a computer-based file of stratigraphic data (STRATDAT) from 1295 wells was assembled during fiscal year 1982. The STRATDAT file was used to produce machine-generated structure contour maps for select stratigraphic horizons and as a source of data for manually constructed regional cross sections. Maps of seven horizons including the Vicksburg, Wilcox, Midway, and Selma groups, Lower Cretaceous System, Paluxy Formation, and Louann Salt illustrate the variability of data density and distribution in the present data base. The influences of the basin's major structural features (Pickens Gilbertown Fault System, Jackson-Mobile Graben, Wiggins Anticline, and Perry Basin) are visible in the cross sections and all maps except the Vicksburg and Louann Salt horizons. The STRATDAT file will become more comprehensive in data distribution and data type in fiscal year 1983 through the addition of stratigraphic data from more completion records, geophysical logs, and seismic refraction interpretations.
Stream analysis of small drainage basins in an ancient landform, Korean Peninsula
NASA Astrophysics Data System (ADS)
Han, Jong-Gyu; Choi, Sung-Ja
2014-12-01
Much of the topography of Korea is ancient, but many Quaternary fault outcrops and marine terraces have been observed in the southeastern part of the Korean Peninsula. Sufficient evidence of a Quaternary fault is lacking in the geological features of the commercially developed Jukbyun and Uljin areas. Knickpoints that develop on streams can be formed by tectonic activity such as faulting and folding, or can result simply from the differential erosion rates of bedrock. In this study, we investigated the relationship between stream steepness and faults in the Jukbyun area. Stream profile analyses of the Bugu and Namdae basins were performed using a digital elevation model to estimate Quaternary tectonic movements. Stream parameters obtained from analysis of the longitudinal stream profiles of the Bugu and Namdae drainage basins in the northeastern part of the Korean Peninsula indicated neotectonic movement. Thirty of the thirty-nine knickpoints that developed in the downstream areas of the fluvial channels corresponded to fault zones. It is thought that fault activity results in knickpoints in river systems. The normalized relative slope (Ksn) value (54.9) of the BS1 stream in the Bugu drainage basin was higher than that (28.8-36.3) of the other streams in both basins, despite a similar lithology to NS1 and NS2. Therefore, we concluded that stream steepness might be a result of tectonic forcing rather than a product of rock strength in the study area and that stream parameters could provide indirect evidence of Quaternary tectonics in ancient landforms.
Kohles, K.M.; Potts, J. ); Reid, F.S.
1991-03-01
The Washakie and Red Desert basins comprise the eastern portion of the Greater Green River basins of southwestern Wyoming. Stratigraphically the basins are dominated by a thick package of Cretaceous clastic sediments, as much as 16,000 ft thick, which resulted from several major transgressive-regressive cycles. Upper Cretaceous strata deposited during the latest cycle contain extensive deposits of commercial hydrocarbons, particularly gas. Much of the present structural configuration of the area is the result of the Laramide Orogeny in Late Cretaceous time. To facilitate a comprehensive geological analysis of the area a computerized subsurface data base was constructed from available well logs for approximately 3,000 wells in the Washakie and Red Desert basins. This data base contains correlated tops for most of the major Upper Cretaceous stratigraphic units, including selected subdivisions and net sand thickness values. Consistent correlations were achieved through the use of a tight, loop-tied cross section and key well network containing over 400 correlated well-logs. A complete suite of structure contour maps on all correlated horizons was generated from the data base with commercially available software. These maps, along with selected computer-generated structural cross sections, reveal a detailed subsurface picture of the Washakie and Red Desert basins. Isopachous maps of selected intervals were also produced to illustrate the Late Cretaceous depositional history of the area.
Numerical Fracture Analysis of Cryogenically Treated Alloy Steel Weldments
NASA Astrophysics Data System (ADS)
Rasool Mohideen, S.; Thamizhmanii, S.; Fatah, M. M. Muhammed Abdul; Saidin, W. Najmuddin W.
2016-02-01
Cryogenic treatment is being used commercially in the industries in the last two decades for improving the life of many engineering component such as bearings and cutting tools. Though their influence in improving the wear resistance of tool materials is well established, the effect of treatment on weldments is not much investigated. In the present work, a two dimensional finite element analysis was carried out on the compact tension specimen model for simulating the treatment process and to study the fracture behaviour. The weldments were modelled by thermo- mechanical coupled field analysis for simulating he temperature distribution in the model during weld pool cooling and introducing thermal stresses due to uneven contraction and cooling. The model was subjected to cryogenic treatment by adopting radiation effect. The fracture analysis was carried out using Rice's J- Integral approach. The analysis produced a similar outcome of experimental results i.e. Increase in the fracture toughness of the specimen after cryogenic treatment in the heat affected zone of weldment.
NASA Astrophysics Data System (ADS)
Mikhailov, V. O.; Parsons, T.; Simpson, R. W.; Timoshkina, E. P.; Williams, C.
2007-01-01
Data on present-day heat flow, subsidence history, and paleotemperature for the Sacramento Delta region, California, have been employed to constrain a numerical model of tectonic subsidence and thermal evolution of forearc basins. The model assumes an oceanic basement with an initial thermal profile dependent on its age subjected to refrigeration caused by a subducting slab. Subsidence in the Sacramento Delta region appears to be close to that expected for a forearc basin underlain by normal oceanic lithosphere of age 150 Ma, demonstrating that effects from both the initial thermal profile and the subduction process are necessary and sufficient. Subsidence at the eastern and northern borders of the Sacramento Valley is considerably less, approximating subsidence expected from the dynamics of the subduction zone alone. These results, together with other geophysical data, show that Sacramento Delta lithosphere, being thinner and having undergone deeper subsidence, must differ from lithosphere of the transitional type under other parts of the Sacramento Valley. Thermal modeling allows evaluation of the rheological properties of the lithosphere. Strength diagrams based on our thermal model show that, even under relatively slow deformation (10-17 s-1), the upper part of the delta crystalline crust (down to 20-22 km) can fail in brittle fashion, which is in agreement with deeper earthquake occurrence. Hypocentral depths of earthquakes under the Sacramento Delta region extend to nearly 20 km, whereas, in the Coast Ranges to the west, depths are typically less than 12-15 km. The greater width of the seismogenic zone in this area raises the possibility that, for fault segments of comparable length, earthquakes of somewhat greater magnitude might occur than in the Coast Ranges to the west.
Mikhailov, V.O.; Parsons, T.; Simpson, R.W.; Timoshkina, E.P.; Williams, C.
2007-01-01
Data on present-day heat flow, subsidence history, and paleotemperature for the Sacramento Delta region, California, have been employed to constrain a numerical model of tectonic subsidence and thermal evolution of forearc basins. The model assumes an oceanic basement with an initial thermal profile dependent on its age subjected to refrigeration caused by a subducting slab. Subsidence in the Sacramento Delta region appears to be close to that expected for a forearc basin underlain by normal oceanic lithosphere of age 150 Ma, demonstrating that effects from both the initial thermal profile and the subduction process are necessary and sufficient. Subsidence at the eastern and northern borders of the Sacramento Valley is considerably less, approximating subsidence expected from the dynamics of the subduction zone alone. These results, together with other geophysical data, show that Sacramento Delta lithosphere, being thinner and having undergone deeper subsidence, must differ from lithosphere of the transitional type under other parts of the Sacramento Valley. Thermal modeling allows evaluation of the rheological properties of the lithosphere. Strength diagrams based on our thermal model show that, even under relatively slow deformation (10−17 s−1), the upper part of the delta crystalline crust (down to 20–22 km) can fail in brittle fashion, which is in agreement with deeper earthquake occurrence. Hypocentral depths of earthquakes under the Sacramento Delta region extend to nearly 20 km, whereas, in the Coast Ranges to the west, depths are typically less than 12–15 km. The greater width of the seismogenic zone in this area raises the possibility that, for fault segments of comparable length, earthquakes of somewhat greater magnitude might occur than in the Coast Ranges to the west.
Multivariate analysis of groundwater resources in Ganga-Yamuna basin (India).
Sargaonkar, Aabha P; Gupta, Apurba; Devotta, Sukumar
2008-07-01
Groundwater quality data on physico-chemical, bacteriological and heavy metal concentrations in three cities (Faridabad, Allahabad and Varanasi) in Ganga-Yamuna basin was subjected to multivariate analysis (MVA) using SPSS. The factors extracted showed high loading (> 0.3) of various parameters, such as Cl, conductivity, TDS, hardness, Na, Mg, and SO4, indicating contamination due to leaching of pollutants. Major manifest variable associated with these factors is the unorganized solid waste dumping practiced in all the cities. Bacterial contamination of hand pump samples in Allahabad is attributed to surface water-groundwater interaction. The factor with high loading of Ca and F is indicative of geological conditions of the region. Wells in Yamuna river sub-watershed exhibit less freshwater recharge, which is attributed to surface water pollution and sediment deposition in the river. Thus, the methodology for hydrogeological analysis is useful to identify critical water quality issues and possible sources of pollution in river basins. PMID:19552076
NASA Astrophysics Data System (ADS)
Dwelle, M. C.; Ivanov, V. Y.; Berrocal, V.
2014-12-01
Forecasting rainfall in areas with sparse monitoring efforts is critical to making inferences about the health of ecosystems and built environments. Recent advances in scientific computing have allowed forecasting and climate models to increase their spatial and temporal resolution. Combined with observed point precipitation from monitoring stations, these models can be used to inform dynamic spatial statistical models for precipitation using methods from geostatistics and machine learning. To prove the feasibility, process, and capabilities of these statistical models, we present a case study of two statistical models of precipitation for the Amazon River basin from 2003-2010 that can infer a spatial process at a point using areal data from numerical model output. We investigate the seasonality and accumulation of rainfall, and the occurrence of no-rainfall and large-rainfall events. These parameters are used since they provide valuable information on possible model biases when using climate models for forecasts of the future process of precipitation in the Amazon basin. This information can be vital for ecosystem, agriculture, and water-resource management. We use observed precipitation data from weather stations, three areal datasets derived from observed precipitation (CFSR, CMORPH-CRT, GPCC) and three climate model precipitation datasets from CMIP5 (MIROC4h, HadGEM2-CC, and GISS-E2H) to construct the models. The observational data in the model domain is sparse, with 195 stations in the approximate 7×106 square kilometers of the Amazon basin, and therefore requires the areal data to create a more robust model. The first model uses the method of Bayesian melding to combine and make inferences from the included data sets, and the second uses a regression model with spatially and temporally-varying coefficients. The models of precipitation are fitted using the areal products and a subset of the point data, while another subset of point data is held out for
NASA Astrophysics Data System (ADS)
Zhi, Y.; Yang, Z. F.; Yin, X. A.
2014-05-01
Decomposition analysis of water footprint (WF) changes, or assessing the changes in WF and identifying the contributions of factors leading to the changes, is important to water resource management. Instead of focusing on WF from the perspective of administrative regions, we built a framework in which the input-output (IO) model, the structural decomposition analysis (SDA) model and the generating regional IO tables (GRIT) method are combined to implement decomposition analysis for WF in a river basin. This framework is illustrated in the WF in Haihe River basin (HRB) from 2002 to 2007, which is a typical water-limited river basin. It shows that the total WF in the HRB increased from 4.3 × 1010 m3 in 2002 to 5.6 × 1010 m3 in 2007, and the agriculture sector makes the dominant contribution to the increase. Both the WF of domestic products (internal) and the WF of imported products (external) increased, and the proportion of external WF rose from 29.1 to 34.4%. The technological effect was the dominant contributor to offsetting the increase of WF. However, the growth of WF caused by the economic structural effect and the scale effect was greater, so the total WF increased. This study provides insights about water challenges in the HRB and proposes possible strategies for the future, and serves as a reference for WF management and policy-making in other water-limited river basins.
NASA Astrophysics Data System (ADS)
Sun, B.; Wang, L.; Dong, P.; Scientific Team Of Applied Geophysics
2010-12-01
The Hailar Basin is one of the most representative basins among the Northeast China Basin Group, which is situated in the east of East Asia Orogene between the Siberia Plate and the North China Plate. Based on the detailed analysis of the Bouguer gravity anomaly, aeromagnetic anomaly as well as petrophysical data, we studied the features of gravity-magnetic fields in the basin and its neighboring areas. A combined approach of Wavelet Multi-scale Decomposition and Power Spectrum Analysis was adopted to quantitatively grade the gravity and magnetic anomalies into four levels. Accordingly, the apparent depths of the source fields can be assessed. The results reveal the crustal density and magnetic structures of the Hailar Basin. Low-order wavelet details of gravity-magnetic anomalies were carried out on studying basin basement structure. Seven major basement faults of the basin were identified, and the basement lithology was discussed and predicted. Three major uplifts and 14 depressions were delineated according to basement depth inversion by the Park method. High-order wavelet approximations of gravity-magnetic anomalies were carried out on studying deep tectonics of the basin. The average Moho depth of the study area is about 40 km, with a mantle uplift located in the northeast of the basin. The average depth of the Curie interface is about 19 km, while the uplift of the Curie interface is in the basin center and its east and west sides are depressions. Finally, inversion of Bouguer gravity anomalies was conducted on an across-basin GGT profile using the Wavelet Multi-scale Decomposition. The inversion results are consistent with those of GGT seismic inversion, suggesting that the Wavelet Multi-scale Decomposition can be applied to distinguish major crustal density interfaces.
Geotechnical Analysis of Five Shelby Tube Samples from H-Area Retention Basin
Langton, C.A.
1999-06-02
Geotechnical and geochemical analyses were performed on five Shelby tube samples collected in the H-Area Retention Basin (HRB) during July and August of 1998. The samples were collected as part of the HRB characterization study. The test results, which are documented in this report, will be used to support the HRB contaminant fate and transport modeling/analysis and to evaluate remedial options. The results will also be used as a base line for future treatability studies.
Numerical analysis of EPR spectra. 8. Relative concentrations
NASA Astrophysics Data System (ADS)
Beckwith, Athelstan L. J.; Brumby, Steven
A method for determining the relative concentrations of paramagnetic species in mixtures by least-squares analysis of the EPR spectra is described. The method is especially useful when the double integration method cannot be used because of overlap between the component spectra. In two examples, the relative steady-state concentrations of free radicals formed during the photolysis of dimethoxymethane/di- tert-butyl peroxide and cyclopropylmethyl methyl ether/di- tert-butyl peroxide/cyclopropane solutions are determined.
Vesselinov, V. V.; Keating, E. H.; Zyvoloski, G. A.
2002-01-01
Predictions and their uncertainty are key aspects of any modeling effort. The prediction uncertainty can be significant when the predictions depend on uncertain system parameters. We analyze prediction uncertainties through constrained nonlinear second-order optimization of an inverse model. The optimized objective function is the weighted squared-difference between observed and simulated system quantities (flux and time-dependent head data). The constraints are defined by the maximization/minimization of the prediction within a given objective-function range. The method is applied in capture-zone analyses of groundwater-supply systems using a three-dimensional numerical model of the Espanola Basin aquifer. We use the finite-element simulator FEHM coupled with parameter-estimation/predictive-analysis code PEST. The model is run in parallel on a multi-processor supercomputer. We estimate sensitivity and uncertainty of model predictions such as capture-zone identification and travel times. While the methodology is extremely powerful, it is numerically intensive.
Experimental and numerical analysis of Al6063 duralumin using Taylor impact test
NASA Astrophysics Data System (ADS)
Kruszka, L.; Anaszewicz, Ł.; Janiszewski, J.; Grązka, M.
2012-08-01
The paper presents results of experimental and numerical analysis of dynamic behaviour Al6063 duralumin. Dynamical experiments were made using Taylor impact test. Experimental results at next step of study were used in numerical analyses of dynamic yield stress of tested material and model parameters of the Johnson-Cook constitutive equation. The main aim of this analysis is to find out dynamical properties of Al6063 duralumin tested in Taylor impact test.
NASA Astrophysics Data System (ADS)
Polovnikov, V. Yu.; Piskunov, M. V.
2014-08-01
The numerical investigation of thermal stresses within low-temperature insulation covering cryogenic pipelines and the numerical probability analysis of low-temperature insulation destruction under the condition of periodic duty were carried out. The minimal longevity values for foamed polyurethane and mineral cotton were established. The results of longevity analysis for foamed polyurethane and mineral cotton under the condition of environment temperature variation were obtained.
An analysis of the carbon balance of the Arctic Basin from 1997 to 2006
McGuire, A.D.; Hayes, D.J.; Kicklighter, D.W.; Manizza, M.; Zhuang, Q.; Chen, M.; Follows, M.J.; Gurney, K.R.; McClelland, J.W.; Melillo, J.M.; Peterson, B.J.; Prinn, R.G.
2010-01-01
This study used several model-based tools to analyse the dynamics of the Arctic Basin between 1997 and 2006 as a linked system of land-ocean-atmosphere C exchange. The analysis estimates that terrestrial areas of the Arctic Basin lost 62.9 Tg C yr-1 and that the Arctic Ocean gained 94.1 Tg C yr-1. Arctic lands and oceans were a net CO2 sink of 108.9 Tg C yr-1, which is within the range of uncertainty in estimates from atmospheric inversions. Although both lands and oceans of the Arctic were estimated to be CO2 sinks, the land sink diminished in strength because of increased fire disturbance compared to previous decades, while the ocean sink increased in strength because of increased biological pump activity associated with reduced sea ice cover. Terrestrial areas of the Arctic were a net source of 41.5 Tg CH4 yr-1 that increased by 0.6 Tg CH4 yr-1 during the decade of analysis, a magnitude that is comparable with an atmospheric inversion of CH4. Because the radiative forcing of the estimated CH4 emissions is much greater than the CO2 sink, the analysis suggests that the Arctic Basin is a substantial net source of green house gas forcing to the climate system.
Analysis of Meteorological Drought in Gandaki River Basin Nepal By Standardized Precipitation Index.
NASA Astrophysics Data System (ADS)
Dahal, P.; Shrestha, N. S.
2014-12-01
This paper presents a comprehensive analysis of meteorological drought phenomenon in Gandaki River Basin of Central Nepal using Standardized Precipitation Index (SPI) computed at different time scales: 3, 6, 12 months and for monsoon (4 month SPI, June to September) and winter (3 month SPI, December to February) seasons. The study based on high-resolution (0.05 degree) daily precipitation data produced by APHRODITE's Water Resources project obtained from Department of Hydrology and Meteorology, Government of Nepal. SPI were computed using monthly precipitation data from 1961 to 2004 for 78 APHRODITE precipitation stations around the basin. According to the trend analysis, most of the stations are characterized by increasing SPI value for all time scales which indicate decreases in drought magnitude in GRB. But few stations at High Mountain show significant decreasing trend. The Principle component analysis is also applied to SPI time series and it enabled to identify the spatial disparities in drought. The areas having high annual precipitation have increasing trends in SPI value and area having low annual precipitation have decreasing trend in SPI value for all time scales. This implies that wet areas are becoming wetter and dry areas are becoming dryer in the basin, which affects the smallholder and subsistence farmers the most.
Quantitative numerical analysis of transient IR-experiments on buildings
NASA Astrophysics Data System (ADS)
Maierhofer, Ch.; Wiggenhauser, H.; Brink, A.; Röllig, M.
2004-12-01
Impulse-thermography has been established as a fast and reliable tool in many areas of non-destructive testing. In recent years several investigations have been done to apply active thermography to civil engineering. For quantitative investigations in this area of application, finite difference calculations have been performed for systematic studies on the influence of environmental conditions, heating power and time, defect depth and size and thermal properties of the bulk material (concrete). The comparison of simulated and experimental data enables the quantitative analysis of defects.
Design of braided composite tubes by numerical analysis method
Hamada, Hiroyuki; Fujita, Akihiro; Maekawa, Zenichiro; Nakai, Asami; Yokoyama, Atsushi
1995-11-01
Conventional composite laminates have very poor strength through thickness and as a result are limited in their application for structural parts with complex shape. In this paper, the design for braided composite tube was proposed. The concept of analysis model which involved from micro model to macro model was presented. This method was applied to predict bending rigidity and initial fracture stress under bending load of the braided tube. The proposed analytical procedure can be included as a unit in CAE system for braided composites.
A Gravity Analysis of the Subsurface Structure of the Utopia Impact Basin
NASA Technical Reports Server (NTRS)
Barnerdt, W. B.
2004-01-01
The large, shallow, circular depression in Utopia Planitia has been identified as a huge impact basin, based on both geological evidence and detailed analysis of MOLA topography. Its diameter (approximately 3000 km) is equivalent to that of the Hellas basin, as is its inferred age (early Noachian). However, there the similarity ends. Their appearance, both surficially and geophysically, are virtually polar opposites. Whereas Hellas is extremely deep with rough terrain and large slopes, high-precision MOLA measurements were required to unambiguously define the smooth, shallow, almost imperceptible bowl of the Utopia basin. Conversely, Utopia displays one of the largest (non-Tharsis-related) positive geoid anomalies on Mars, in contrast to a more subdued negative anomaly over Hellas. As these two features presumably formed roughly contemporaneously by similar mechanisms, it is reasonable to assume that they were originally quite similar, and that their differences are due largely to different paths of subsequent modification. The obvious source for these differences is in their elevations: Hellas is located in the southern highlands at a rim elevation of about 3km, whereas Utopia is in the lowlying northern plains, at an average elevation of 4 km. Thus Utopia has been in an especially gravitationally favorable position to be subjected to infilling, for example, by lava flows, sedimentation, or water. In fact, its floor was almost certainly the lowest point on the planet at one time, and it would have been the termination point for down-slope drainage from over two-thirds of Mars. Thus the nature of the material filling this basin has strong connections to the sedimentary and/or volcanic processes acting on Mars in the Noachian and Early Hesperian periods. In particular, it may be able to shed some light on amount and persistence of water on early Mars in general and in the Utopia basin in particular. In this study I will use the inferred early correspondence between
NASA Astrophysics Data System (ADS)
Kult, Jonathan M.; Fry, Lauren M.; Gronewold, Andrew D.; Choi, Woonsup
2014-11-01
Methods for predicting streamflow in areas with limited or nonexistent measures of hydrologic response commonly rely on regionalization techniques, where knowledge pertaining to gauged watersheds is transferred to ungauged watersheds. Hydrologic response indices have frequently been employed in contemporary regionalization research related to predictions in ungauged basins. In this study, we developed regionalization models using multiple linear regression and regression tree analysis to derive relationships between hydrologic response and watershed physical characteristics for 163 watersheds in the Great Lakes basin. These models provide an empirical means for simulating runoff in ungauged basins at a monthly time step without implementation of a rainfall-runoff model. For the dependent variable in these regression models, we used monthly runoff ratio as the indicator of hydrologic response and defined it at two temporal scales: (1) treating all monthly runoff ratios as individual observations, and (2) using the mean of these monthly runoff ratios for each watershed as a representative observation. Application of the models to 62 validation watersheds throughout the Great Lakes basin indicated that model simulations were far more sensitive to the temporal characterization of hydrologic response than to the type of regression technique employed, and that models conditioned on individual monthly runoff ratios (rather than long term mean values) performed better. This finding is important in light of the increased usage of hydrologic response indices in recent regionalization studies. Models using individual observations for the dependent variable generally simulated monthly runoff with reasonable skill in the validation watersheds (median Nash-Sutcliffe efficiency = 0.53, median R2 = 0.66, median magnitude of the deviation of runoff volume = 13%). These results suggest the viability of empirical approaches to simulate runoff in ungauged basins. This finding is
Asymptotic analysis of dissipative waves with applications to their numerical simulation
NASA Technical Reports Server (NTRS)
Hagstrom, Thomas
1990-01-01
Various problems involving the interplay of asymptotics and numerics in the analysis of wave propagation in dissipative systems are studied. A general approach to the asymptotic analysis of linear, dissipative waves is developed. It was applied to the derivation of asymptotic boundary conditions for numerical solutions on unbounded domains. Applications include the Navier-Stokes equations. Multidimensional traveling wave solutions to reaction-diffusion equations are also considered. A preliminary numerical investigation of a thermo-diffusive model of flame propagation in a channel with heat loss at the walls is presented.
Harper, W.V.; Basinger, K.L.; Furr, J.M.
1988-01-01
This report details a geostatistical analysis of potentiometric data from the Pennsylvanian aquifer in the Palo Duro Basin, Texas. Such an analysis is a part of an overall uncertainty analysis for a high-level waste repository in salt. Both an expected potentiometric surface and the associated standard error surface are produced. The Pennsylvanian data are found to be well explained by a linear trend with a superimposed spherical semivariogram. A cross-validation of the analysis confirms this. In addition, the cross-validation provides a point-by-point check to test for possible anomalous data. The analysis is restricted to that portion of the Pennsylvanian aquifer that lies to the southwest of the Amarillo Uplift. The Pennsylvanian is absent is some areas across the uplift and data to the northeast were not used in this analysis. The surfaces produced in that analysis are included for comparison. 9 refs., 15 figs.
NASA Astrophysics Data System (ADS)
Avellar, J.; Duarte, L. G. S.; da Mota, L. A. C. P.; de Melo, N.; Skea, J. E. F.
2012-09-01
A set of Maple routines is presented, fully compatible with the new releases of Maple (14 and higher). The package deals with the numerical evolution of dynamical systems and provide flexible plotting of the results. The package also brings an initial conditions generator, a numerical solver manager, and a focusing set of routines that allow for better analysis of the graphical display of the results. The novelty that the package presents an optional C interface is maintained. This allows for fast numerical integration, even for the totally inexperienced Maple user, without any C expertise being required. Finally, the package provides the routines to calculate the fractal dimension of boundaries (via box counting). New version program summary Program Title: Ndynamics Catalogue identifier: %Leave blank, supplied by Elsevier. Licensing provisions: no. Programming language: Maple, C. Computer: Intel(R) Core(TM) i3 CPU M330 @ 2.13 GHz. Operating system: Windows 7. RAM: 3.0 GB Keywords: Dynamical systems, Box counting, Fractal dimension, Symbolic computation, Differential equations, Maple. Classification: 4.3. Catalogue identifier of previous version: ADKH_v1_0. Journal reference of previous version: Comput. Phys. Commun. 119 (1999) 256. Does the new version supersede the previous version?: Yes. Nature of problem Computation and plotting of numerical solutions of dynamical systems and the determination of the fractal dimension of the boundaries. Solution method The default method of integration is a fifth-order Runge-Kutta scheme, but any method of integration present on the Maple system is available via an argument when calling the routine. A box counting [1] method is used to calculate the fractal dimension [2] of the boundaries. Reasons for the new version The Ndynamics package met a demand of our research community for a flexible and friendly environment for analyzing dynamical systems. All the user has to do is create his/her own Maple session, with the system to
Dimensionless Analysis and Numerical Modeling of Rebalancing Phenomena During Levitation
NASA Astrophysics Data System (ADS)
Gao, Lei; Shi, Zhe; Li, Donghui; McLean, Alexander; Chattopadhyay, Kinnor
2016-06-01
Electromagnetic levitation (EML) has proved to be a powerful tool for research activities in areas pertaining to materials physics and engineering. The customized EML setups in various fields, ranging from solidification to nanomaterial manufacturing, require the designing of stable levitation systems. Since the elevated droplet is opaque, the most effective way to research on EML is mathematical modeling. In the present study, a 3D model was built to investigate the rebalancing phenomenon causing instabilities during droplet melting. A mathematical model modified based on Hooke's law (spring) was proposed to describe the levitation system. This was combined with dimensionless analysis to investigate the generation of levitation forces as it will significantly affect the behavior of the spring model.
Numerical analysis for in-plane behavior of infilled frames
Jamal, B.D.; Bennett, R.M. . Dept. of Civil Engineering); Flanagan, R.D. )
1992-02-27
A nonlinear finite element study was conducted for the Y-12 Plant to evaluate the in-plane behavior of masonry infilled steel frames. ABAQUS was used to develop the finite element model and perform a parametric analysis. The model was verified by comparing the results with the experimental program series carried out at the University of Brunswick, Canada. The initial stiffness could be matched using an elastic model with an interface element. The ultimate load could be matched using the ABAQUS nonlinear concrete model for the infill. A softened interface was used to account for the localized mortar crushing that tends to occur at the corners of infilled frames. This model was used to match the secant stiffness at approximately 50% of the ultimate load. A parametric study was performed on the initial stiffness. Results indicated that an appropriate equivalent strut could closely match the behavior.
NASA Astrophysics Data System (ADS)
Loegering, Markus; Anka, Zahie; Rodriguez, Jorge; Marchal, Denis; di Primio, Rolando; Vallejo, Eduardo; Kohler, Guillermina; Pangaro, Francisco
2010-05-01
The analysis of a dense 2D seismic reflection dataset and 12 exploration wells data, allowed us to reconstruct the geological evolution of the Colorado Basin, offshore Argentina. We identified and mapped the major syn- and post-rift seismic sequences, and their boundaries such as unconformities and regional seismic markers, present on the continental shelf and slope (water depths from 50 to 1800 m) of the Colorado Basin. Seismic-to-well log correlations, as well as integration with biostratigraphic data provided a chrono-stratigraphic framework for the interpreted horizons. The construction of isochronal (twt) maps provided a 3D spatial visualisation of the stratigraphic relationship among the sequences. The maps show a change in configuration from the break-up unconformity (130 Ma) to the present-day seafloor. The break-up unconformity displays a central EW-elongated graben which prevails on the overlying sequences up to the Miocene. The EW Colorado basin turns NW-SE towards the East, going perpendicular to the present-day continental margin (oriented NE-SW). The strong obliquity of the basin orientation related to the direction corresponding to the opening of the South Atlantic (NE-SW) suggests a structural control from the pre-rift basement on the rift and post-rift sequences. Starting from the break-up unconformity, the history of basin filling is illustrated up to the flat seafloor. The basin sag phase is represented by the sequences deposited between the break-up unconformity and the Colorado discontinuity (Aptian to Campanian). The Campanian to Eocene successions are more or less parallel- layered suggesting sequence aggradation. The distribution of liquid/gas hydrocarbon-leakage features (i.e. gas chimneys, mud volcanoes, and seabed pockmarks) should allow the definition of potential migration pathways. In this sense, a systematic mapping of these paleo- and present-day features observed in the seismic profiles has been performed and their distribution was
Theoretical and numerical analysis of the corneal air puff test
NASA Astrophysics Data System (ADS)
Simonini, Irene; Angelillo, Maurizio; Pandolfi, Anna
2016-08-01
Ocular analyzers are used in the current clinical practice to estimate, by means of a rapid air jet, the intraocular pressure and other eye's parameters. In this study, we model the biomechanical response of the human cornea to the dynamic test with two approaches. In the first approach, the corneal system undergoing the air puff test is regarded as a harmonic oscillator. In the second approach, we use patient-specific geometries and the finite element method to simulate the dynamic test on surgically treated corneas. In spite of the different levels of approximation, the qualitative response of the two models is very similar, and the most meaningful results of both models are not significantly affected by the inclusion of viscosity of the corneal material in the dynamic analysis. Finite element calculations reproduce the observed snap-through of the corneal shell, including two applanate configurations, and compare well with in vivo images provided by ocular analyzers, suggesting that the mechanical response of the cornea to the air puff test is actually driven only by the elasticity of the stromal tissue. These observations agree with the dynamic characteristics of the test, since the frequency of the air puff impulse is several orders of magnitude larger than the reciprocal of any reasonable relaxation time for the material, downplaying the role of viscosity during the fast snap-through phase.
Numerical methods for analysis of clay tile infills
Flanagan, R.D.; Tenbus, M.A.; Bennett, R.M.
1993-10-20
Recent Department of Energy requirements have led to a comprehensive evaluation of the industrial facilities at the Oak Ridge Y-12 Plant. The structures consist of simply connected steel frames infilled with structural clay tile walls. The objective of the evaluation was to determine the stability of the unreinforced infills, and whether they provide the lateral capacity necessary to resist the moderate seismic hazard at the site. Due to lack of information on the behavior of structural clay tile infills, various large-scale tests were performed to investigate the in-plane, out-of-plane and combined in-plane and out-of-plane behavior. The results of these tests are briefly summarized, and the development of analytical guidelines based on these tests is given. Little interaction between in-plane and out-of-plane loads was observed, both in terms of stiffness and strength. Out-of-plane stability can be examined panel by panel based on arching action. Inter-story drift does not appear to present a stability problem for the type of infill construction investigated. In-plane behavior may be adequately modeled with a nonlinear compression strut. A typical building is chosen for an illustrative application. The methodology and results of the seismic analysis are presented for this structure.
Experimental and numerical analysis of automotive gearbox rattle noise
NASA Astrophysics Data System (ADS)
Kadmiri, Younes; Rigaud, Emmanuel; Perret-Liaudet, Joël; Vary, Laurence
2012-06-01
The aim of this work is to characterize the rattle noise of automotive gearboxes, resulting from impacts between toothed wheels of unselected gear ratios. These stereo-mechanical impacts are modeled by a coefficient of restitution which describes damping during the squeezing of the lubricant film for approaching surfaces, and the elastic deformation of impacting bodies. The dynamic response of the loose gear first depends on the design parameters and the engine operating conditions. The unknown parameters are the drag torque and the coefficient of restitution. They are identified experimentally through implementation of two optical encoders in an actual automotive gearbox and the operation of a specific test bench which replicates the automotive power train. Models of the different drag torque sources are validated from analysis of the free damped response of the driveline. The coefficient of restitution and its probability density function are measured from experiments under stationary operating conditions. A nonlinear model is built. The dynamic response of the loose gear depends on the dimensionless backlash, the coefficient of restitution and a dimensionless parameter proposed to describe the rattle excitation level. Experiments under controlled excitation are performed to validate the assumptions, to confirm the ability of the parameter proposed to describe the rattle noise threshold, and to characterize the dynamic response. The nonlinear model predictions are fitted with the drag torque and coefficient of restitution previously identified. They are compared with measurements to demonstrate the ability of the model to predict gear rattle for any loose gear, any gearbox and any operating condition.
NASA Astrophysics Data System (ADS)
Ahn, Kuk-Hyun; Palmer, Richard
2016-09-01
Despite wide use of regression-based regional flood frequency analysis (RFFA) methods, the majority are based on either ordinary least squares (OLS) or generalized least squares (GLS). This paper proposes 'spatial proximity' based RFFA methods using the spatial lagged model (SLM) and spatial error model (SEM). The proposed methods are represented by two frameworks: the quantile regression technique (QRT) and parameter regression technique (PRT). The QRT develops prediction equations for flooding quantiles in average recurrence intervals (ARIs) of 2, 5, 10, 20, and 100 years whereas the PRT provides prediction of three parameters for the selected distribution. The proposed methods are tested using data incorporating 30 basin characteristics from 237 basins in Northeastern United States. Results show that generalized extreme value (GEV) distribution properly represents flood frequencies in the study gages. Also, basin area, stream network, and precipitation seasonality are found to be the most effective explanatory variables in prediction modeling by the QRT and PRT. 'Spatial proximity' based RFFA methods provide reliable flood quantile estimates compared to simpler methods. Compared to the QRT, the PRT may be recommended due to its accuracy and computational simplicity. The results presented in this paper may serve as one possible guidepost for hydrologists interested in flood analysis at ungaged sites.
NASA Astrophysics Data System (ADS)
Liu, K. K.; Li, C. H.; Cai, Y. P.; Xu, M.; Xia, X. H.
2014-05-01
In this paper, a fuzzy multi-attribute decision analysis approach (FMADAA) was developed for supporting the evaluation of water resources security in nine provinces within the Yellow River basin. A numerical approximation system and a modified left-right scoring approach were adopted to cope with the uncertainties in the acquired information. Also, four conventional multi-attribute decision analysis (MADA) methods were implemented in the evaluation model for impact evaluation, including simple weighted addition (SWA), weighted product (WP), cooperative game theory (CGT) and technique for order preference by similarity to ideal solution (TOPSIS). Moreover, several aggregation methods including average ranking procedure, Borda and Copeland methods were used to integrate the ranking results, helping rank the water resources security in those nine provinces as well as improving reliability of evaluation results. The ranking results showed that the water resources security of the entire basin was in critical condition, including the insecurity and absolute insecurity states, especially in Shanxi, Inner Mongolia and Ningxia provinces in which water resources were lower than the average quantity in China. Hence, the improvement of water eco-environment statuses in the above-mentioned provinces should be prioritized in the future planning of the Yellow River basin.
Mehrian, Majid Ramezani; Hernandez, Raul Ponce; Yavari, Ahmad Reza; Faryadi, Shahrzad; Salehi, Esmaeil
2016-08-01
Lake Urmia is the second largest hypersaline lake in the world in terms of surface area. In recent decades, the drop in water level of the lake has been one of the most important environmental issues in Iran. At present, the entire basin is threatened due to abrupt decline of the lake's water level and the consequent increase in salinity. Despite the numerous studies, there is still an ambiguity about the main cause of this environmental crisis. This paper is an attempt to detect the changes in the landscape structure of the main elements of the whole basin using remote sensing techniques and analyze the results against climate data with time series analysis for the purpose of achieving a more clarified illustration of processes and trends. Trend analysis of the different affecting factors indicates that the main cause of the drastic dry out of the lake is the huge expansion of irrigated agriculture in the basin between 1999 and 2014. The climatological parameters including precipitation and temperature cannot be the main reasons for reduced water level in the lake. The results show how the increase in irrigated agricultural area without considering the water resources limits can lead to a regional disaster. The approach used in this study can be a useful tool to monitor and assess the causality of environmental disaster. PMID:27406207
Twumasi, Yaw A.; Merem, Edmund C.
2008-01-01
This paper uses remote sensing and geographic information systems (GIS); and descriptive statistics in the assessment of environmental change along the Savannah River Basin of Georgia. Results of the study show that Savannah River basin side of Georgia has been experiencing environmental change due to several decades of relentless pressure induced by anthropocentric activities and host of other socio-economic factors. Normalized Difference Vegetation Index (NDVI) analysis of the area also shows a decline in vegetation cover. The pace of ecological change showed some variations across time and space. Generally, the results point to a decline in water bodies, vegetation, and increase in population, loss of harvested cropland, farms and increasing threats to the environmental systems of the region. PMID:18441406
Trend analysis of rainfall time series for Sindh river basin in India
NASA Astrophysics Data System (ADS)
Gajbhiye, Sarita; Meshram, Chandrashekhar; Mirabbasi, Rasoul; Sharma, S. K.
2015-06-01
The study of precipitation trends is critically important for a country like India whose food security and economy are dependent on the timely availability of water such as 83 % water used for agriculture sector, 12 % for industry sector and only 5 % for domestic sector. In this study, the historical rainfall data for the periods 1901-2002 and 1942-2002 of the Sindh river basin, India, were analysed for monthly, seasonal and annual trends. The conventional Mann-Kendall test (MK) and Mann-Kendall test (MMK), after the removal of the effect of all significant autocorrelation coefficients, and Sen's slope estimator were used to identify the trends. Kriging technique was used for interpolating the spatial pattern using Arc GIS 9.3. The analysis suggested significant increase in the trend of rainfall for seasonal and annual series in the Sindh basin during 1901-2002.
Trend analysis of rainfall time series for Sindh river basin in India
NASA Astrophysics Data System (ADS)
Gajbhiye, Sarita; Meshram, Chandrashekhar; Mirabbasi, Rasoul; Sharma, S. K.
2016-08-01
The study of precipitation trends is critically important for a country like India whose food security and economy are dependent on the timely availability of water such as 83 % water used for agriculture sector, 12 % for industry sector and only 5 % for domestic sector. In this study, the historical rainfall data for the periods 1901-2002 and 1942-2002 of the Sindh river basin, India, were analysed for monthly, seasonal and annual trends. The conventional Mann-Kendall test (MK) and Mann-Kendall test (MMK), after the removal of the effect of all significant autocorrelation coefficients, and Sen's slope estimator were used to identify the trends. Kriging technique was used for interpolating the spatial pattern using Arc GIS 9.3. The analysis suggested significant increase in the trend of rainfall for seasonal and annual series in the Sindh basin during 1901-2002.
Morphometrical Analysis and Peak Runoff Estimation for the Sub-Lower Niger River Basin, Nigeria
NASA Astrophysics Data System (ADS)
Salami, Adebayo Wahab; Amoo, Oseni Taiwo; Adeyemo, Joshiah Adetayo; Mohammed, Abdulrasaq Apalando; Adeogun, Adeniyi Ganiyu
2016-03-01
This study utilized Spatial Information Technology (SIT) such as Remote Sensing (RS), a Geographical Information System (GIS), the Global Positioning System (GPS) and a high-resolution Digital Elevation Model (DEM) for a morphometrical analysis of five sub-basins within the Lower Niger River Basin, Nigeria. Morpho-metrical parameters, such as the total relief, relative relief, relief ratio, ruggedness number, texture ratio, elongation ratio, circularity ratio, form factor ratio, drainage density, stream frequency, sinuosity factor and bifurcation ratio, have been computed and analyzed. The study revealed that the contribution of the morphometric parameters to flooding suggest catchment No. 1 has the least concentration time and the highest runoff depth. Catchment No. 4 has the highest circularity ratio (0.35) as the most hazardous site where floods could reach a great volume over a small area.
Copula-Based Flood Frequency Analysis at Ungauged Basin Confluences: Nashville, Tennessee
Kao, Shih-Chieh; Chang, Ni-Bin
2012-01-01
Many cities are located at or near the confluence of streams where availability of water resources may be enhanced to sustain user needs while also posing an increased flooding risk from multiple tributaries. An accurate flood frequency estimator that models the joint flood potential at a basin confluence is needed. Given that long-term flow observations are often unavailable, estimating flood frequency at ungaged basin confluences proves challenging. Through the use of copulas, this case study demonstrates how an improved flood frequency analysis can be performed for stream confluences at Nashville, TN. The approach involves four major steps including initial data quality control, fitting of marginal distributions of tributary peak flows, construction of a suitable dependence structure, and identification of flood frequency at the confluence point based on synthesized peak flows. This case study may help researchers and practitioners develop a better understanding of joint flood frequency with consideration of upstream dam regulation among several contributing watersheds.
In-situ analysis of solid bitumen in coal: Examples from the Bowen Basin and the Illinois Basin
Mastalerz, Maria; Glikson, M.
2000-01-01
Solid bitumen and associated vitrinite from selected coals from the Bowen Basin and the Illinois Basin were studied using electron microprobe and micro-FTIR techniques. The coal studied covers a range of vitrinite reflectance from 0.59% to 1.33%. Carbon content in the bitumen is generally lower than in vitrinite in coals with vitrinite reflectance below 0.67%. In coals with reflectance above 0.67%, carbon content of bitumen is higher than in vitrinite, reflecting higher aromaticity due to hydrocarbon generation. Sulfur and iron content are comparable between vitrinite and bitumen. Functional group distribution suggests the presence of two types of bitumen in the Illinois Basin coals. The more aliphatic variety occurring in veins and cleats is interpreted as pre-gas generation bitumen, and the more aromatic variety filling cells and voids in inertinite as post-gas generation bitumen. (C) 2000 Elsevier Science B.V. All rights reserved.Solid bitumen and associated vitrinite from selected coals from the Bowen Basin and the Illinois Basin were studied using electron microprobe and micro-FTIR techniques. The coal studied covers a range of vitrinite reflectance from 0.59% to 1.33%. Carbon content in the bitumen is generally lower than in vitrinite in coals with vitrinite reflectance below 0.67%. In coals with reflectance above 0.67%, carbon content of bitumen is higher than in vitrinite, reflecting higher aromaticity due to hydrocarbon generation. Sulfur and iron content are comparable between vitrinite and bitumen. Functional group distribution suggests the presence of two types of bitumen in the Illinois Basin coals. The more aliphatic variety occurring in veins and cleats is interpreted as pre-gas generation bitumen, and the more aromatic variety filling cells and voids in inertinite as post-gas generation bitumen.
NASA Astrophysics Data System (ADS)
Syvitski, James P. M.; Hutton, Eric W. H.
2001-07-01
Numerical simulators of the dynamics of strata formation of continental margins fuse information from the atmosphere, ocean and regional geology. Such models can provide information for areas and times for which actual measurements are not available, or for when purely statistical estimates are not adequate by themselves. SEDFLUX is such a basin-fill model, written in ANSI-standard C, able to simulate the delivery of sediment and their accumulation over time scales of tens of thousands of years. SEDFLUX includes the effects of sea-level fluctuations, river floods, ocean storms, and other relevant environmental factors (climate trends, random catastrophic events), at a time step (daily to yearly) that is sensitive to short-term variations of the seafloor. SEDFLUX combines individual process-response models into one fully interactive model, delivering a multi-sized sediment load onto and across a continental margin, including sediment redistribution by (1) river mouth dynamics, (2) buoyant surface plumes, (3) hyperpycnal flows, (4) ocean storms, (5) slope instabilities, (6) turbidity currents, and (7) debris flows. The model allows for the deposit to compact, to undergo tectonic processes (faults, uplift) and isostatic subsidence from the sediment load. The modeled architecture has a typical vertical resolution of 1-25 cm, and a typical horizontal resolution of between 1 and 100 m.
NASA Astrophysics Data System (ADS)
Kim, Seonok; Wang, Sookyun; Lee, Minhee
2016-04-01
Long term containment of stored CO2 in deep geological formation will be dependent on the performance of the caprock to prevent the buoyant CO2. The study aims to identify CO2-brine-caprock interactions and develop a framework, within which, geochemical reaction in caprock due CO2 injection can be evaluated. A series of autoclave experiments were conducted with caprock from drilling cores of Pohang basin where many researches have been focused as a candidate for geological CO2 sequestration at 50℃ with 100 bar of CO2 for 15day. XRD, XRF, ICP-OES and SEM-EDS studies were performed to characterize the reaction products. Also the numerical modeling with use of Geochemist's Workbench 10.0.6 (GWB) in two stages was performed. The first one was aimed at simulating the immediate changes in the aquifer and insulating caprocks impacted by the beginning of CO2 injection (100 days), the second enabling assessment of long-term effects of sequestration (10000 years). The simulations allowed to determine the suitability of the formation for carbon dioxide storage.
Bradfield, A.D.
1986-01-01
Coal-mining impacts on Smoky Creek, eastern Tennessee were evaluated using water quality and benthic invertebrate data. Data from mined sites were also compared with water quality and invertebrate fauna found at Crabapple Branch, an undisturbed stream in a nearby basin. Although differences in water quality constituent concentrations and physical habitat conditions at sampling sites were apparent, commonly used measures of benthic invertebrate sample data such as number of taxa, sample diversity, number of organisms, and biomass were inadequate for determining differences in stream environments. Clustering algorithms were more useful in determining differences in benthic invertebrate community structure and composition. Normal (collections) and inverse (species) analyses based on presence-absence data of species of Ephemeroptera, Plecoptera, and Tricoptera were compared using constancy, fidelity, and relative abundance of species found at stations with similar fauna. These analyses identified differences in benthic community composition due to seasonal variations in invertebrate life histories. When data from a single season were examined, sites on tributary streams generally clustered separately from sites on Smoky Creek. These analyses compared with differences in water quality, stream size, and substrate characteristics between tributary sites and the more degraded main stem sites, indicated that numerical classification of invertebrate data can provide discharge-independent information useful in rapid evaluations of in-stream environmental conditions. (Author 's abstract)
Loomis, K.B.; Ingle, J.C. Jr.
1988-03-01
The Neogene Point Arena basin of northwestern California is located west of the San Andreas fault system and south of the Mendocino triple junction. Key units of the Point Arena sequence are exposed from Iversen Landing north to Point Arena, California, including the Oligocene-Miocene Iversen Basalt (23.8 Ma), the lower Miocene Skooner Gulch and Gallaway Formations, and the lower to mid-Miocene Point Arena Formation. Lithologic and thickness data, together with evidence of age and paleobathymetry from both onshore and offshore sequences in the Point Arena basin, were used in a geohistory analysis of basin development. The resulting geohistory diagram tracks depths of specific stratigraphic zones, variations in paleobathymetry, and patterns of subsidence and uplift during late Paleogene through Neogene time. Geohistory analysis indicates that the late Paleogene margin was uplifted during approach of the Pacific-Farallon spreading ridge. Subsequently, a pulse of volcanism during latest Oligocene-Miocene signaled initial Neogene subsidence of the margin as marked by the Iversen Basalt. Subsidence likely involved both initial thermal subsidence as well as later transtensional deformation during the passage of the Mendocino triple junction and initiation of the San Andreas fault system. Rapid initial subsidence was accompanied by deposition of turbidites (Skooner Gulch and Gallaway Formation). The highly organic shales and petroliferous sands of the overlying Point Arena Formation indicate an abrupt cessation of turbidite deposition and a slower rate of basin subsidence during the middle Miocene. Episodes of warping from mid-Miocene through Holocene can be attributed to crustal flexing associated with wrench tectonism, with a major event bringing the Point Arena sequence above sea level during the late Pliocene-Pleistocene.
Teresa E. Jordan
2015-11-15
This collection of files are part of a larger dataset uploaded in support of Low Temperature Geothermal Play Fairway Analysis for the Appalachian Basin (GPFA-AB, DOE Project DE-EE0006726). Phase 1 of the GPFA-AB project identified potential Geothermal Play Fairways within the Appalachian basin of Pennsylvania, West Virginia and New York. This was accomplished through analysis of 4 key criteria or ‘risks’: thermal quality, natural reservoir productivity, risk of seismicity, and heat utilization. Each of these analyses represent a distinct project task, with the fifth task encompassing combination of the 4 risks factors. Supporting data for all five tasks has been uploaded into the Geothermal Data Repository node of the National Geothermal Data System (NGDS). This submission comprises the data for Thermal Quality Analysis (project task 1) and includes all of the necessary shapefiles, rasters, datasets, code, and references to code repositories that were used to create the thermal resource and risk factor maps as part of the GPFA-AB project. The identified Geothermal Play Fairways are also provided with the larger dataset. Figures (.png) are provided as examples of the shapefiles and rasters. The regional standardized 1 square km grid used in the project is also provided as points (cell centers), polygons, and as a raster. Two ArcGIS toolboxes are available: 1) RegionalGridModels.tbx for creating resource and risk factor maps on the standardized grid, and 2) ThermalRiskFactorModels.tbx for use in making the thermal resource maps and cross sections. These toolboxes contain “item description” documentation for each model within the toolbox, and for the toolbox itself. This submission also contains three R scripts: 1) AddNewSeisFields.R to add seismic risk data to attribute tables of seismic risk, 2) StratifiedKrigingInterpolation.R for the interpolations used in the thermal resource analysis, and 3) LeaveOneOutCrossValidation.R for the cross validations used in
NASA Technical Reports Server (NTRS)
Pittman, C. M.; Howser, L. M.
1972-01-01
The differential equations governing the transient response of the char layer of an ablating axisymmetric body, internal pyrolysis gas flow effects being considered, have been derived. These equations have been expanded into finite difference form and programed for numerical solution on a digital computer. Numerical results compare favorably with simplified exact solutions. The complete numerical analysis was used to obtain solutions for two representative body shapes subjected to a typical entry heating environment. Pronounced effects of the lateral flow of pyrolysis gases on the mass flow field within the char layer and the associated surface and pyrolysis interface recession rates are shown.
Geometric invariants for initial data sets: analysis, exact solutions, computer algebra, numerics
NASA Astrophysics Data System (ADS)
Valiente Kroon, Juan A.
2011-09-01
A personal perspective on the interaction of analytical, numerical and computer algebra methods in classical Relativity is given. This discussion is inspired by the problem of the construction of invariants that characterise key solutions to the Einstein field equations. It is claimed that this kind of ideas will be or importance in the analysis of dynamical black hole spacetimes by either analytical or numerical methods.
Testing and Analysis of Consolidated Sludge Samples from the 105 K East Basin Floor and Canisters
Bredt, Paul R. ); Delegard, Calvin H. ); Schmidt, Andrew J. ); Silvers, Kurt L. )
2000-11-06
The testing reported here was performed on K East Basin consolidated sludge samples to generate data needed for the evaluation and design of the systems that will be used to disposition the K Basin sludge to T-Plant for interim storage. The tests were conducted by Pacific Northwest National Laboratory from May through November 1999 under the direction of the Spent Nuclear Fuel (SNF) Project. The samples used in the work discussed here were collected by the SNF Characterization Project from the KE Basin floor and canisters during March and April 1999. These samples (3 from the floor and 3 from the canisters) were shipped to the storage pool at the Postirradiation Testing Laboratory (327 Building) and later transferred to the PNNL Radiochemical Processing Laboratory (325 Building), where they were recovered for testing and analysis. Testing activities presented in this report include particle size measurement via wet sieving, sludge settling and sludge density measurements, sludge shear strength measurement, and measurement of sludge dissolution enthalpy to ascertain the uranium metal content of the sludge. Section 1.0 provides the summary and conclusions to date. Section 2.0 describes the consolidated sample container system, the sample collection and transfer, inspection, and recovery of the samples for testing. Section 3.0 describes the testing methodologies and presents the results and analyses.
NASA Astrophysics Data System (ADS)
Russo, T. A.; Fisher, A. T.; Hanson, R. T.; Lockwood, B. S.
2011-12-01
The Pajaro Valley Groundwater Basin (PVGB), central coastal California, relies almost entirely on groundwater to satisfy agricultural and municipal/domestic needs (83% and 17% of water usage, respectively). The rate of groundwater extraction and other outflows from the PVGB over the last five decades has exceeded the total rate of inflows, resulting in chronic overdraft. This has led to a lowering of water levels throughout the basin and seawater intrusion near the coast. Managed aquifer recharge (MAR) likely will become increasingly important for sustaining groundwater supply in future years; however, identifying areas amenable to MAR remains challenging. A geographical information system (GIS) analysis was completed to evaluate areas of the PVGB suitable for MAR. Initially GIS analyses used topographic, land use, bedrock geology, and soil property data to assess shallow conditions, and subsequent analyses have included subsurface information such as aquifer and associated confining layer locations, properties, thicknesses, and historical changes in water levels. Additional GIS coverages included potential supplemental water supplies. A preliminary map of MAR site suitability suggests that about 10% of the basin may be suitable for MAR. Ongoing field testing will provide "ground truth" for the assessment of GIS-based calculations, and both field and GIS analyses will provide critical input for regional hydrologic models that will be used to quantify the potential influences of different MAR scenarios. Collectively, these studies are helping to evaluate management options for improving long-term groundwater conditions throughout the PVGB.
NASA Astrophysics Data System (ADS)
Vonhof, H.; Lubbe, J. V. D.; Joordens, J. J.; Feibel, C. S.; Junginger, A.; Garcin, Y.; Krause-Nehring, J.; Beck, C.; Johnson, T. C.
2015-12-01
Lake Turkana in northern Kenya is one of the largest lakes in the East African Rift System (EARS) that experienced significant climate-driven lake level variation over the Holocene. Arguably the most important feature of Holocene climate change in the EARS is the termination of the African Humid Period (AHP), that caused a ~70 meter lake level drop in Lake Turkana. The precise hydrological response to the termination of the AHP is potentially complex, because Lake Turkana lies at the cross roads of two large atmospheric convection systems; the Intertropical Convergence Zone (ITCZ) and the Congo Air Boundary (CAB). Shifting of these atmospheric systems around the end of the AHP dramatically rearranged spatial rainfall patterns in the Turkana Basin catchment, causing changes in relative runoff contributions from the different sub-catchments in the Turkana Basin. We here present a Holocene Turkana lake water Sr-isotope reconstruction, based on the analysis of well-dated lacustrine ostracods and shells. This reconstruction reveals consistently high Sr isotope values for the early Holocene, followed by a remarkable drop of Sr isotope ratios around the AHP termination. We interpret this pattern to represent a westward shift in the location of the CAB, leading to the reduction and eventual shutdown of runoff contribution from the Chew Bahir Basin to the Turkana Basin at the end of the AHP. The record demonstrates the exceptional suitability of Sr isotope data for this type of paleohydrological reconstructions. This is mainly due to the chemically conservative Sr-isotope mass balance in EARS lake systems, which is insensitive to environmental change at seasonal timescales that so often overprints the longer term climate signal in stable (oxygen and carbon) isotope records of these lakes. Furthermore, when Sr-isotope signatures of the contributing sub-catchments are known, the observed Sr isotope trends can be interpreted in terms of spatial shifts in climate driven runoff
NASA Astrophysics Data System (ADS)
Huang, X.; Bandilla, K.; Celia, M. A.; Bachu, S.
2013-12-01
Geological carbon sequestration can significantly contribute to climate-change mitigation only if it is deployed at a very large scale. This means that injection scenarios must occur, and be analyzed, at the basin scale. Various mathematical models of different complexity may be used to assess the fate of injected CO2 and/or resident brine. These models span the range from multi-dimensional, multi-phase numerical simulators to simple single-phase analytical solutions. In this study, we consider a range of models, all based on vertically-integrated governing equations, to predict the basin-scale pressure response to specific injection scenarios. The Canadian section of the Basal Aquifer is used as a test site to compare the different modeling approaches. The model domain covers an area of approximately 811,000 km2, and the total injection rate is 63 Mt/yr, corresponding to 9 locations where large point sources have been identified. Predicted areas of critical pressure exceedance are used as a comparison metric among the different modeling approaches. Comparison of the results shows that single-phase numerical models may be good enough to predict the pressure response over a large aquifer; however, a simple superposition of semi-analytical or analytical solutions is not sufficiently accurate because spatial variability of formation properties plays an important role in the problem, and these variations are not captured properly with simple superposition. We consider two different injection scenarios: injection at the source locations and injection at locations with more suitable aquifer properties. Results indicate that in formations with significant spatial variability of properties, strong variations in injectivity among the different source locations can be expected, leading to the need to transport the captured CO2 to suitable injection locations, thereby necessitating development of a pipeline network. We also consider the sensitivity of porosity and
NASA Astrophysics Data System (ADS)
Modu, B.; Herbert, B.
2014-11-01
The Chad basin which covers an area of about 2.4 million kilometer square is one of the largest drainage basins in Africa in the centre of Lake Chad .This basin was formed as a result of rifting and drifting episode, as such it has no outlet to the oceans or seas. It contains large area of desert from the north to the west. The basin covers in part seven countries such as Chad, Nigeria, Central African Republic, Cameroun, Niger, Sudan and Algeria. It is named Chad basin because 43.9% falls in Chad republic. Since its formation, the basin continues to experienced water shortage due to the activities of Dams combination, increase in irrigations and general reduction in rainfall. Chad basin needs an external water source for it to be function at sustainable level, hence needs for exploitation of higher east African river basin called Congo basin; which covers an area of 3.7 million square km lies in an astride the equator in west-central Africa-world second largest river basin after Amazon. The Congo River almost pans around republic of Congo, the democratic republic of Congo, the Central African Republic, western Zambia, northern Angola, part of Cameroun, and Tanzania. The remotely sensed imagery analysis and observation revealed that Congo basin is on the elevation of 275 to 460 meters and the Chad basin is on elevation of 240 meters. This implies that water can be drained from Congo basin via headrace down to the Chad basin for the water sustainability.
NASA Astrophysics Data System (ADS)
Hinder, Ian; Buonanno, Alessandra; Boyle, Michael; Etienne, Zachariah B.; Healy, James; Johnson-McDaniel, Nathan K.; Nagar, Alessandro; Nakano, Hiroyuki; Pan, Yi; Pfeiffer, Harald P.; Pürrer, Michael; Reisswig, Christian; Scheel, Mark A.; Schnetter, Erik; Sperhake, Ulrich; Szilágyi, Bela; Tichy, Wolfgang; Wardell, Barry; Zenginoğlu, Anıl; Alic, Daniela; Bernuzzi, Sebastiano; Bode, Tanja; Brügmann, Bernd; Buchman, Luisa T.; Campanelli, Manuela; Chu, Tony; Damour, Thibault; Grigsby, Jason D.; Hannam, Mark; Haas, Roland; Hemberger, Daniel A.; Husa, Sascha; Kidder, Lawrence E.; Laguna, Pablo; London, Lionel; Lovelace, Geoffrey; Lousto, Carlos O.; Marronetti, Pedro; Matzner, Richard A.; Mösta, Philipp; Mroué, Abdul; Müller, Doreen; Mundim, Bruno C.; Nerozzi, Andrea; Paschalidis, Vasileios; Pollney, Denis; Reifenberger, George; Rezzolla, Luciano; Shapiro, Stuart L.; Shoemaker, Deirdre; Taracchini, Andrea; Taylor, Nicholas W.; Teukolsky, Saul A.; Thierfelder, Marcus; Witek, Helvi; Zlochower, Yosef
2013-01-01
The Numerical-Relativity-Analytical-Relativity (NRAR) collaboration is a joint effort between members of the numerical relativity, analytical relativity and gravitational-wave data analysis communities. The goal of the NRAR collaboration is to produce numerical-relativity simulations of compact binaries and use them to develop accurate analytical templates for the LIGO/Virgo Collaboration to use in detecting gravitational-wave signals and extracting astrophysical information from them. We describe the results of the first stage of the NRAR project, which focused on producing an initial set of numerical waveforms from binary black holes with moderate mass ratios and spins, as well as one non-spinning binary configuration which has a mass ratio of 10. All of the numerical waveforms are analysed in a uniform and consistent manner, with numerical errors evaluated using an analysis code created by members of the NRAR collaboration. We compare previously-calibrated, non-precessing analytical waveforms, notably the effective-one-body (EOB) and phenomenological template families, to the newly-produced numerical waveforms. We find that when the binary's total mass is ˜100-200M⊙, current EOB and phenomenological models of spinning, non-precessing binary waveforms have overlaps above 99% (for advanced LIGO) with all of the non-precessing-binary numerical waveforms with mass ratios ⩽4, when maximizing over binary parameters. This implies that the loss of event rate due to modelling error is below 3%. Moreover, the non-spinning EOB waveforms previously calibrated to five non-spinning waveforms with mass ratio smaller than 6 have overlaps above 99.7% with the numerical waveform with a mass ratio of 10, without even maximizing on the binary parameters.
New mapping of Radlandi basin and detailed analysis of its inner plains
NASA Astrophysics Data System (ADS)
Minelli, Francesco; Giorgetti, Carolina; Mondini, Alessandro; Pauselli, Cristina; Mancinelli, Paolo
2013-04-01
NEW MAPPING OF RADITLADI BASIN AND DETAILED ANALYSIS OF ITS INNER PLAINS. Francesco Minelli 1, Carolina Giorgetti 1, Alessandro C. Mondini 2, Cristina Pauselli 1, Paolo Mancinelli1. 1 Gruppo di Geologia Strutturale e Geofisica (GSG), Dipartimento di Scienze della Terra, Università degli Studi di Perugia, 06123, Perugia, Italy . Email: minelli91@yahoo.it. 2 CNR IRPI Perugia, 06123, Perugia. Introduction: The Raditladi basin is a large peak-ring impact crater discovered during the MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) first flyby of Mercury in January 2008 [1]. The Raditladi basin is relatively young [2], and the study of the internal structures give an indication of the processes that acted recently in Mercury's geological history. Geological mapping: We first present the geological mapping of Raditladi crater. In the map we defined different sub-units on the base of previous studies [4][5] and surface morphology and reflectance. Through a GIS software we associated a polygonal layer to each sub-unit, this allowed to distinguish nine different layers. Due to the similarities with the Rachmaninoff basin, to define sub-units mapped on Raditladi, we adopted Rachmaninoff crater's units definitions made by Marchi et al. (2011) [4]. Structures analysis : We also mapped secondary structures consisting in concentric troughs arranged in a circular pattern. We defined two different kinds of troughs: (i) structures characterized by a distinct flat floor and interpretable as grabens, and (ii) structures with linear and curvilinear segments [5]. Inner plain deposit: The analysis of the topography made possible the estimation of the deposit's thickness. The measurement of the thickness is possible thanks to the presence of two small craters, crater A and crater, located in Raditladi's Inner plain. Observing the morphology of the two small craters' rim and hummocky central floor, we distinguished two different units: the shallower consists in
Free vibrations of beam-mass-spring systems: analytical analysis with numerical confirmation
NASA Astrophysics Data System (ADS)
Darabi, Mohammad A.; Kazemirad, Siavash; Ghayesh, Mergen H.
2012-04-01
Free vibrations of a beam-mass-spring system with different boundary conditions are analyzed both analytically and numerically. In the analytical analysis, the system is divided into three subsystems and the effects of the spring and the point mass are considered as internal boundary conditions between any two neighboring subsystems. The partial differential equations governing the motion of the subsystems and internal boundary conditions are then solved using the method of separation of variables. In the numerical analysis, the whole system is considered as a single system and the effects of the spring and point mass are introduced using the Dirac delta function. The Galerkin method is then employed to discretize the equation of motion and the resulting set of ordinary differential equations are solved via eigenvalue analysis. Analytical and numerical results are shown to be in very good agreement.
NASA Astrophysics Data System (ADS)
Liu, K. K.; Li, C. H.; Cai, Y. P.; Xu, M.; Xia, X. H.
2014-01-01
In this paper, a Fuzzy Multi-Attribute Decision Analysis Approach (FMADAA) was adopted in water resources security evaluation for the nine provinces in the Yellow River basin in 2006. A numerical approximation system and a modified left-right scoring approach were adopted to cope with the uncertainties in the acquired information. Four multi-attribute decision making methods were implemented in the evaluation model for impact evaluation, including simple weighted addition (SWA), weighted product (WP), cooperative game theory (CGT) and technique for order preference by similarity to ideal solution (TOPSIS) which could be used for helping rank the water resources security in those nine provinces as well as the criteria alternatives. Moreover, several aggregation methods including average ranking procedure, borda and copeland methods were used to integrate the ranking results. The ranking results showed that the water resources security of the entire basin is in critical, insecurity and absolute insecurity state, especially in Shanxi, Inner Mongolia and Ningxia provinces in which water resources were lower than the average quantity in China. Hence, future planning of the Yellow River basin should mainly focus on the improvement of water eco-environment status in the provinces above.
Tectono-Sedimentary Analysis of Rift Basins: Insights from the Corinth Rift, Greece
NASA Astrophysics Data System (ADS)
Gawthorpe, Robert; Ford, Mary
2015-04-01
the Pliocene rift fill is similar to rift initiation in high sediment flux locations in the west and rift climax in low sediment flux locations in the east. Major shifts in the locus of fault activity within the Corinth Rift further complicate tectono-stratigraphy analysis of its basin fill. Pliocene depocentres are largely located onshore, south of the present-day Gulf of Corinth and involved activity that was distributed among north- and south-dipping faults. A northward shift in the southern rift margin in the early Pleistocene, established the present-day Gulf of Corinth as the site of several main depocentres and caused abandonment, uplift and reworking of a large portion of the Pliocene rift. Changes in the locus of fault activity during the Pleistocene record a change from activity on north- and south-dipping faults to mainly north-dipping faults. Such shifts in fault activity have a profound effect on the basin fill, with new footwall areas subject to subaerial exposure and incision while contemporaneous hangingwall depocentres undergo rapid subsidence and drowning. Such local complexity is not surprising, but factors such as major antecedent sediment transport pathways and marked temporal and spatial shifts in fault activity make application of conventional tectono-sedimentary subdivsions of pre-, syn-, and post-rift difficult to apply at the basin-scale.
Hugman, R.H.
1988-01-01
Deep gas resources have assumed a growing role in the United States gas picture since the mid-1960s. The deep Anadarko basin has been one of the areas of heavy activity, and is thought to contain a significant portion of the remaining unproven deep gas resource in the lower-48 states. A detailed analysis of gas production and proven reserves in the deep basin has established the characteristics and historical importance of each of the major plays and productive formations. The analysis should prove to be a valuable tool in estimating the undiscovered gas potential of the deep basin. Through 1985, there were 908 completions in the deep Anadarko basin. These completions accounted for 6.10 tcf of proven ultimate recovery, an average of 6.72 bcf per completion. In general, there is one completion per well and one well per section. Thus, ultimate recovery per completion represents ultimate recovery per section. The Hunton Group has the highest mean ultimate recovery at 15.3 bcf, followed by the Arbuckle Group at 10.1 bcf. In an attempt to evaluate existing resource appraisals of the deep basin, the areal distribution of production by formation was determined for the mature, shallow part of the basin. Over 20,000 completions were included in this analysis, demonstrating a significant database application. By using this distribution as a guide, along with certain other constraints, a range of 15-47 tcf of undiscovered potential was estimated.
NASA Astrophysics Data System (ADS)
Nicoll, Graeme; Straathof, Gijs; Tait, Jenny; Lo, Khalidou; Ousmane, N'diaye; El Moctar Dahmada, Mohamed; Berndt, Jasper; Key, Roger
2010-05-01
We have dated over 800 detrital zircon grains from the Neoproterozoic sediments within the Taoudeni Basin of Mauritania on the West African craton. This sequence of sediments preserves a relatively condensed mixed continental and marine succession as well as Neoproterozoic glacial and glacially influenced deposits. The underlying Archaean and Birimian basement of the West African craton is exposed on the Reguibat shield in the north, and on the Leo shield in the south although smaller inliers occur scattered along the Bassaride and Mauritanide belts, as well as in the core of the Anti-Atlas belt. The large West African craton is totally surrounded by Pan-African fold belts. Sedimentation within the Taoudeni basin started around 1000Ma and lasted until the end of the Carboniferous. The basin is 1000-1500 km in diameter and the sedimentary pile is on average 3000 m thick. All dated zircons in the stratigraphically lowest Char and Atar Groups are older than ~1800Ma. These groups show a strong input of 2950 and 2075Ma ages, indicating sourcing from the local underlying granitic and gneissic basement. These basal sediments also include a large input from a rare 2475Ma source. Samples from the upper Assebet El Hassiane Group contain numerous zircons of 2000-900Ma. While the Neoproterozoic Marinoan glaciogenic "Triad" Jbeliat Group and stratigraphically above formations show a large range of 3200-595Ma ages. We have also undertaken a detailed Carbon isotope profile study through the carbonates which cap the Glacial Jbeliat Group. The upper part of the Jbeliat cap carbonate displays a distinct and pronounced rise from -4.3 to +3.8 13C, followed by the final demise of carbonate productivity. This positive trend is consistent with the upper part of the globally extensive Ghaub/Nantuo/Marinoan cap carbonate sequences. This world-wide sequence is characterized by composite negative-to-positive trends up section and so this isotope stratigraphy along with the zircon data helps
Ruskauff, G.J.
1996-12-31
A regional groundwater flow model has been developed to be used as a management tool for the Albuquerque Basin. It is crucial to recognize the impact of the inherent uncertainty in aquifer hydrogeology when applying the model, and an understanding of the effects of uncertainty can be accomplished using a probabilistic approach to address the role of natural variability of aquifer properties on management strategies. Statistical analysis shows that the hydraulic conductivity data is moderately skewed to the right, but is not lognormal. Geostatistical analysis revealed zonal anisotropy oriented due north-south, which is directly related to the flow direction of the ancestral Rio Grande which laid down the Upper Santa Fe Group deposits. The presence of multiple depositional environments within the Upper Santa Fe Group violates the assumption of stationarity. This can be circumvented by choosing the simulation search radius so that local stationarity holds, or by separating the basin into two portions to be simulated separately and then combined for flow model analysis.
Numerical simulation of wind effects on the temperature analysis of bridges
NASA Astrophysics Data System (ADS)
Chen, Lan; Li, Fengwu; Zhou, Linren; Ji, Jing
2016-04-01
Structural temperatures and their uneven distributions have significantly negative effects on bridges. It is very important to accurately calculate the structural temperatures. Structural temperatures are deeply affected by the surrounding weather conditions, and the environmental wind is a critical factor. In this study, the wind effects on the thermal analysis of bridges are investigated using numerical simulation. Frist, the traditional theory and method are briefly introduced to show the important effects of wind on structural heat transfer analysis. Then, a new approach is proposed to take account of the wind effects for temperature analysis of bridges. At last, numerical study based on the finite element transient heat transfer analysis of a box-girder bridge is carried out and discussed to verify the proposed method. The results indicate that the proposed method is more reasonable than the traditional methods. This method can be easily implemented in practice for temperature analysis of bridges.
Analysis of Rainfall Changes in Transnational Basins in Portugal and Spain
NASA Astrophysics Data System (ADS)
Guerreiro, S. B.; Kilsby, C. G.; Serinaldi, F.
2012-04-01
The impact of climate regime variability on the hydrology and water resources of the major transnational basins in Iberia (Portugal and Spain) is being studied. Spain is the source of the three major rivers that flow through Portugal, leaving this country in a vulnerable position. There is a strong interannual precipitation variability in Iberia, with very wet and very dry years occurring frequently. Situations of water scarcity are already frequent in the south of Portugal and Spain, so in the future, a critical problem of water availability for Iberia might arise. An analysis of changes in rainfall records covering the three major transnational basins was performed, using data from Spain and Portugal which are normally considered separately. This study area, defined by basins instead of countries, is more coherent for water resources analysis. Change point and trend analysis was performed on rainfall records in the transnational basins of rivers Douro, Tagus and Guadiana for the period 1961 to 2009. Non-parametric tests (Pettitt test, cusum test and Mann-Kendall test) were used in order not to have to assume a specific distribution for the data. Field significance was taken into account when calculating trends and change points. The importance of spatial correlation when calculating field significance was demonstrated. As well as finding changes in rainfall which have great significance for water resources, some important issues are raised as to the nature of changes in rainfall to be expected. Significant decreases in rainfall were found for the month of February and, to a lesser extent, March. Significant increases in rainfall were found for October in the Spanish side of Douro and Tagus catchments. The NAO index was considered as a possible explanation for the changes detected. It was also demonstrated that changes in rainfall cannot always be interpreted as trends or change points because the pattern of change can be more complex than these two simplistic
Discovery of a 450 km diameter, multi-ring basin on Mars through analysis of MOLA topographic data
NASA Astrophysics Data System (ADS)
Frey, Herbert; Sakimoto, Susan E. H.; Roark, James H.
Mars Orbiter Laser Altimeter (MOLA) topographic data have revealed a previously unknown, 450 km wide, 2 km deep basin centered at 30N, 312W near the Phison Rupes. This basin, as large as and deeper than the obvious Cassini impact basin located 1000 km to the SW, is not apparent in the existing but good quality Viking imagery. Gridded MOLA data show the feature as a closed depression. Based on analysis of slope breaks readily visible in two MOLA profiles, we suggest this Phison Rupes Basin has three topographic rings with diameters approximately 350, 455 and 670 km. These rings outline a region of lower impact crater density and smoother inter-crater plains. Similar previously unknown features may exist elsewhere on Mars, and MOLA topographic data may be able to locate them.
Analysis of Proterozoic rifting and subsequent subsidence of the Central Congo Basin
NASA Astrophysics Data System (ADS)
Kadima Kabongo, Etienne; Sebagenzi Mwene Ntabwoba, Stanislas; Lucazeau, Francis
2010-05-01
The Central Basin (or Cuvette Centrale) of Congo is a late-Proterozoic to Recent basin covering near one million km2 with up to 9 km of sediment. Its subsidence has been related to a preexisting failed rift (Daly et al, 1992), whose origin, geometry and structure remain largely unknown. Here we present a combined analysis of subsidence and gravity that provides new lines of evidence for a rift origin. Although the dataset for the Central Basin is poor and has not been improved for a long time (only four deep wells with depths between 1856 and 4666 meters and 33 seismic lines covering 2900 km), it is sufficient for the first order characteristics. The analysis of wells data reveals that the long term subsidence (~450 m.y.) and present-day surface heat flow (~40 mWm-2) are both characteristic of a 250 km thick thermal lithosphere. This is consistent with the Archean age of the craton but not with thermal reworking during Paleozoic as hypothesized by Artemieva (2006). From the seismic lines, we can derive a 3D geometrical basin model divided into three different units defined by two major uncomformities. Each layer is assigned an average density value inferred from geophysical logs and then gravity effect is determined and subtracted from the observed gravity anomalies. The residual map shows a positive SE-NW elongated structure that can be related to a possible rift prior to basin subsidence. In order to determine the associated crustal structure, we simply assumed that the post-rift subsidence is flexural and that the rift isostasy is governed by a depth of necking. The procedure involves first flexural backstripping of sediments assuming a given Equivalent Elastic Thickness EET and then determination of the crustal thickness assuming a given depth of necking DON. EET and DON are varied in order to obtain the minimum misfit between predicted and observed gravity. The best results are obtained for EET = 100 km, DON = 10 km and an initial crust thickness of 35 km. The
NASA Astrophysics Data System (ADS)
Dalla Valle, Giacomo; Trincardi, Fabio; Foglini, Federica; Campiani, Elisabetta; Pellegrini, Claudio
2016-04-01
The Plio-Pleistocene sedimentary succession of the western continental margin that surround the Southern Adriatic basin mainly consists of contourite depositional systems. The architectural stacking pattern of the contourites-linked bodies is sometimes interrupted by the presence of large-scale mass-transport complexes (MTCs). MTCs are spatially diffused along the margin and are characterized by high variability in size, morphology and geometries. In the northern sector of the margin MTCs derive from the remobilisation of upper-slope contourite drifts, whereas in the southern sector of the margin sedimentary instability involves shelf-margin, progradational deposits. The most prominent MTC of the northern sector of the margin is the Gondola Slide (GS) a large, deep-seated MTC composed of at least three distinct MTDs involving up to 40km3 of sediments. The events that have generated these MTDs have been enclosed within a robust chronological framework using sedimentary shallow piston-cores collected along the continental slope. The reconstruction of the age of these MTDs indicates that failures have repeatedly occurred along the margin during at least the last 55,000 years. Therefore, the GS case indicates that sediment instability processes can span a large portion of a sea-level cycle, pointing to triggering mechanisms that are independent from variations in the relative sea level position. The repeated GS failure events are therefore interpreted to be mainly triggered by earthquake shocks. The Southern Adriatic basin represents a seismically active area and earthquakes are generally cluster along long-lived shear zones. One of these zones, the Gondola Zone, which run across the shelf and the slope, close to the GS-MTC, has been site of paleoseismology analysis, indicating recent (younger than 5.5 kyr) tectonic deformation through E-W strike-slip faulting . Basin-scale MTDs characterize also the southern sector of the continental margin. MTDs are present both
Trend analysis of selected water-quality constituents in the Verde River Basin, central Arizona
Baldys, S. )
1990-01-01
Temporal trends of eight water quality constituents at six data collection sites in the Verde River basin in central Arizona were investigated using seasonal Kendall tau and ordinary least-squares regression methods of analysis. The constituents are dissolved solids, dissolved sulfate, dissolved arsenic, total phosphorus, pH, total nitrite plus nitrate-nitrogen, dissolved iron, and fecal coliform bacteria. Increasing trends with time in dissolved-solids concentrations of 7 to 8 mg/L/yr at Verde River near Camp Verde were found at significant level. An increasing trend in dissolved-sulfate concentrations of 3.59 mg/L/yr was also found at Verde River near Camp Verde, although at nonsignificant levels. Statistically significant decreasing trends with time in dissolved-solids and dissolved-sulfate concentrations were found at Verde River above Horseshoe Reservoir, which is downstream from Verde River near Camp Verde. Observed trends in the other constituents do not indicate the emergence of water quality problems in the Verde River basin. Analysis of the eight water quality constituents generally indicate nonvarying concentration levels after adjustment for seasonality and streamflow were made.
Ediger, V.S.
1986-01-01
The Productive Coal Measures are the most important unit because major coal deposition in this basin is unique for the Newark Supergroup. There is a good relationship between the rock color, specific gravity, and organic matter content of the carbonaceous mudrocks of the Vinita Beds. These mudrocks show cyclic stratification whose average thickness is about 13 m. The variation of some sedimentological and palynological parameters suggests that these lacustrine meso-scale cycles were formed as a result of cyclic variation in depth and extent of the Richmond lake every 42,000 years, approximately. Ninety-three fossil spores-pollen taxa are encountered from the Productive Coal Measures and Vinita Beds. The Productive Coal Measures flora is dominated by spores, especially Aratrisporites, whereas the Vinita Beds flora by gymnospermous pollen. A transitional flora also exists between them. As a result of correlation between them. As a results of correlation between the European and North American biozonse, it is concluded that the paludal Productive Coal Measures are probably synchronous with European Lettenkohle which is of late Ladinian age in most part. The lacustrine-deltaic Vinita Beds were deposited in latest Ladinian-early Carnian. Sedimentation of these units lasted about 4 million years starting from 232 Ma. Paleogeographic studies show that the sedimentation in the early rift basins was strongly influenced from the transgression of the Tethys Sea into the depressions of the proto-Atlantic region. The presence of coal in the Richmond Basin and vicinity may be related to changes in the sedimentary-tectonic pattern or in climate caused by transgressions, and the initiation of earliest rifting around the Carolina Trough.
NASA Astrophysics Data System (ADS)
Wiejak, W.; Wymysłowski, A.
2016-01-01
Travelling Wave Tube (TWT) is an electronic vacuum microwave device, which is used as a high power microwave amplifier, mainly in telecommunication purposes, e.g. radar systems. TWT's is an alternative solution in comparison to semiconductor devices in case of high power and high frequency applications. Thermal behaviour of TWT is one of the key aspects influencing its reliability and working parameters. The main goal of the research was to perform analytical, experimental and numerical analysis of a temperature distribution of a low band TWT in case of a typical working condition. Because the theoretical analysis seems to be very complex thus it was decided to compare the experimental results with the numerical simulations as well as with the simplified analytical formulas. As a first step of the presented research, the analytical analysis and numerical modelling of the helix TWT was carried out. The objective of the thermal analysis was to assess the temperature distribution in different parts of the helix TWT assembly during the extreme standard and working conditions. As a second stage of the research the numerical results were validated by the experimental measurements, which were carried out using a specially designed TWT test samples and corresponding experimental measurement tools.
Research in progress in applied mathematics, numerical analysis, and computer science
NASA Technical Reports Server (NTRS)
1990-01-01
Research conducted at the Institute in Science and Engineering in applied mathematics, numerical analysis, and computer science is summarized. The Institute conducts unclassified basic research in applied mathematics in order to extend and improve problem solving capabilities in science and engineering, particularly in aeronautics and space.
NASA Technical Reports Server (NTRS)
Heldenfels, Richard R
1951-01-01
A numerical method is presented for the stress analysis of stiffened-shell structures of arbitrary cross section under nonuniform temperature distributions. The method is based on a previously published procedure that is extended to include temperature effects and multicell construction. The application of the method to practical problems is discussed and an illustrative analysis is presented of a two-cell box beam under the combined action of vertical loads and a nonuniform temperature distribution.
[Numerical Analysis of Particle Trajectories in Living Cells under Uncertainty Conditions].
Pisarev, A S; Rukolaine, S A; Samsonov, A M; Samsonova, M G
2015-01-01
We have developed a numerical method for the analysis of particle trajectories in living cells, where a type of movement is determined by Akaike's information criterion, while model parameters are identified by a weighted least squares method. The method is realized in computer software, written in the Java programming language, that enables us to automatically conduct the analysis of trajectories. The method is tested on synthetic trajectories with known parameters, and applied to the analysis of replication complexes in cells, infected with hepatitis C virus. Results of the analysis are in agreement with available data on the movement of biological objects along microtubules. PMID:26591609
NASA Astrophysics Data System (ADS)
Kavetski, D.; Clark, M. P.; Fenicia, F.
2011-12-01
Hydrologists often face sources of uncertainty that dwarf those normally encountered in many engineering and scientific disciplines. Especially when representing large scale integrated systems, internal heterogeneities such as stream networks, preferential flowpaths, vegetation, etc, are necessarily represented with a considerable degree of lumping. The inputs to these models are themselves often the products of sparse observational networks. Given the simplifications inherent in environmental models, especially lumped conceptual models, does it really matter how they are implemented? At the same time, given the complexities usually found in the response surfaces of hydrological models, increasingly sophisticated analysis methodologies are being proposed for sensitivity analysis, parameter calibration and uncertainty assessment. Quite remarkably, rather than being caused by the model structure/equations themselves, in many cases model analysis complexities are consequences of seemingly trivial aspects of the model implementation - often, literally, whether the start-of-step or end-of-step fluxes are used! The extent of problems can be staggering, including (i) degraded performance of parameter optimization and uncertainty analysis algorithms, (ii) erroneous and/or misleading conclusions of sensitivity analysis, parameter inference and model interpretations and, finally, (iii) poor reliability of a calibrated model in predictive applications. While the often nontrivial behavior of numerical approximations has long been recognized in applied mathematics and in physically-oriented fields of environmental sciences, it remains a problematic issue in many environmental modeling applications. Perhaps detailed attention to numerics is only warranted for complicated engineering models? Would not numerical errors be an insignificant component of total uncertainty when typical data and model approximations are present? Is this really a serious issue beyond some rare isolated
Numerical simulation analysis on Wenchuan seismic strong motion in Hanyuan region
NASA Astrophysics Data System (ADS)
Chen, X.; Gao, M.; Guo, J.; Li, Z.; Li, T.
2015-12-01
69227 deaths, 374643 injured, 17923 people missing, direct economic losses 845.1 billion, and a large number houses collapse were caused by Wenchuan Ms8 earthquake in Sichuan Province on May 12, 2008, how to reproduce characteristics of its strong ground motion and predict its intensity distribution, which have important role to mitigate disaster of similar giant earthquake in the future. Taking Yunnan-Sichuan Province, Wenchuan town, Chengdu city, Chengdu basin and its vicinity as the research area, on the basis of the available three-dimensional velocity structure model and newly topography data results from ChinaArray of Institute of Geophysics, China Earthquake Administration, 2 type complex source rupture process models with the global and local source parameters are established, we simulated the seismic wave propagation of Wenchuan Ms8 earthquake throughout the whole three-dimensional region by the GMS discrete grid finite-difference techniques with Cerjan absorbing boundary conditions, and obtained the seismic intensity distribution in this region through analyzing 50×50 stations data (simulated ground motion output station). The simulated results indicated that: (1)Simulated Wenchuan earthquake ground motion (PGA) response and the main characteristics of the response spectrum are very similar to those of the real Wenchuan earthquake records. (2)Wenchuan earthquake ground motion (PGA) and the response spectra of the Plain are much greater than that of the left Mountain area because of the low velocity of the shallow surface media and the basin effect of the Chengdu basin structure. Simultaneously, (3) the source rupture process (inversion) with far-field P-wave, GPS data and InSAR information and the Longmenshan Front Fault (source rupture process) are taken into consideration in GMS numerical simulation, significantly different waveform and frequency component of the ground motion are obtained, though the strong motion waveform is distinct asymmetric
NASA Technical Reports Server (NTRS)
Conel, J. E.; Lang, H. R.; Paylor, E. D.; Alley, R. E.
1985-01-01
A Landsat-4 Thematic Mapper (TM) image of the Wind River Basin area in Wyoming is currently under analysis for stratigraphic and structural mapping and for assessment of spectral and spatial characteristics using visible, near infrared, and short wavelength infrared bands. To estimate the equivalent Lambertian surface reflectance, TM radiance data were calibrated to remove atmospheric and instrumental effects. Reflectance measurements for homogeneous natural and cultural targets were acquired about one year after data acquisition. Calibration data obtained during the analysis were used to calculate new gains and offsets to improve scanner response for earth science applications. It is shown that the principal component images calculated from the TM data were the result of linear transformations of ground reflectance. In images prepared from this transform, the separation of spectral classes was independent of systematic atmospheric and instrumental factors. Several examples of the processed images are provided.
Uncertainty analysis of a long term reactive transport modeling of CO2 storage at Subei Basin, China
NASA Astrophysics Data System (ADS)
Shi, X.; Zheng, F.; Wu, J.; Zhao, L.; Chen, Y.; Xu, H.
2012-12-01
Geological storage of CO2 in deep saline aquifers is one of the most promising means for mitigating climate change. Here we reported a numerical modeling study of the long term storage of CO2 in a saline aquifer at the northern Jiangsu basin, which is one of the most promising reservoirs for geological storage in China. Based on the preliminary study of geological formation in the northern Jiangsu Basin, the Yancheng Formation is selected as the suitable saline aquifer for CO2 storage, owing to (1) multiple sandstone-mudstone sequences' structure consisting of gray coarse sandstone-sandy conglomerate and reddish brown mudstone; (2) the good reservoir quality of sandstone with high permeability and porosity; (3) adequate burning depth (>1000m); (4) occurrence of high salinity formation water. A 2D vertical radial geometry model was built using TOUGHREACT to predict how CO2 will be trapped because of geochemical reactions for long term simulations. The primary minerals of sandstone stratum are quartz, k-feldspar, Na-feldspar, epidote, almandine, muscovite, biotite, pyrite, hornblende and hematite. Various sources of uncertainties are associated with the cumulative CO2 sequestration amount, especially mineral precipitation and dissolution kinetic (i.e., rate) parameters have a large impact on mineral trapping. In this content, the cumulative amount of CO2 mineral sequestration is considered as the response function and its influence of eight sources of uncertainties is studied, namely the intrinsic permeability, the porosity, the pore compressibility, the capillary model parameters, the residual fluid and gas saturation and the salinity. Unlike the commonly used "one factor at a time" approach (local sensitivity analysis), we used global sensitivity analysis to measure parameter importance so that the potential co-operative effects between input parameters are also investigated. Results of this study can be used as an inductive tool to enhance understanding of
NASA Technical Reports Server (NTRS)
1994-01-01
This report summarizes research conducted at the Institute for Computer Applications in Science and Engineering in applied mathematics, fluid mechanics, and computer science during the period October 1, 1993 through March 31, 1994. The major categories of the current ICASE research program are: (1) applied and numerical mathematics, including numerical analysis and algorithm development; (2) theoretical and computational research in fluid mechanics in selected areas of interest to LaRC, including acoustics and combustion; (3) experimental research in transition and turbulence and aerodynamics involving LaRC facilities and scientists; and (4) computer science.
Numerical analysis of elliptic reflector radiating into lossy dielectric half-space
NASA Astrophysics Data System (ADS)
Chen, Yinchao; Beker, Benjamin
1995-05-01
Numerical analysis of an elliptic reflector above a lossy dielectric half-space is presented. The equivalence principle is used in of the combined-field surface integral equations for the currents on the reflector and air-to-lossy-half-space interface. An approximate model for the equivalent electric and magnetic currents on the interface is used to calculate the fields inside the lossy half-space. The numerical results show that the lossy half-space is an effective tool for focusing the radiated beam; especially in the shallow region, even for high values of the lossy permittivity.
Gover, A.; Friedman, A.; Luccio, A.
1986-09-01
A full 3-D Analysis of super-radiant (bunched electron) free electron harmonic radiation is presented. A generalized form of the FEL pendulum equation was derived and numerically solved. Both spectral and phasor formulation were developed to treat the radiation in the time domain. In space the radiation field is expanded in terms of either a set of free space discrete modes or plane waves. The numerical solutions reveal some new distinctly 3-D effects to which we provide a physical explanation. 12 refs., 9 figs., 5 tabs.
Study and numerical analysis on formability of quenching and partitioning steel sheets of auto-body
NASA Astrophysics Data System (ADS)
Hu, Xing; Liu, Yifan; Zhu, Lin
2013-05-01
Advanced high strength steel is the basic structure material for lightweight design and safety enhancement for automobile industry. Quenching and partitioning steel is a recently developed kind of low carbon and low alloy material with retained Austenite for the requirements of both high strength and high ductility. This paper focuses on the formability of a hinge pillar for some car under numerical modelling analysis. The results show that QP980 has an equal elongation comparing with DP590. Moreover, the numerical modelling results of QP980 are more sensitive to the selection of yielding equation comparing with DP590.
Numerical analysis of a measured efficiency hysteresis on a bulb turbine model
NASA Astrophysics Data System (ADS)
Houde, S.; Carrier, A.; Buron, J. D.; Deschênes, C.
2014-03-01
Within the framework of the BulbT project, simulations were performed to understand the origin of a measured hysteresis on the efficiency hill chart of a bulb turbine model. This hysteresis is associated with a sharp drop of efficiency located at slightly higher discharge than the best efficiency operating condition. It appears as a variation in the turbine performance whether an operating condition located in the efficiency drop is reached from a lower or a higher discharge. This hysteresis was reproduced numerically using Reynolds Averaged Navier Stokes (RANS) simulations. The paper presents the experimental results, the numerical methodology and a comprehensive analysis of the simulations to shed light on this interesting phenomenon.
Holmquist-Johnson, C. L.
2009-01-01
River spanning rock structures are being constructed for water delivery as well as to enable fish passage at barriers and provide or improve the aquatic habitat for endangered fish species. Current design methods are based upon anecdotal information applicable to a narrow range of channel conditions. The complex flow patterns and performance of rock weirs is not well understood. Without accurate understanding of their hydraulics, designers cannot address the failure mechanisms of these structures. Flow characteristics such as jets, near bed velocities, recirculation, eddies, and plunging flow govern scour pool development. These detailed flow patterns can be replicated using a 3D numerical model. Numerical studies inexpensively simulate a large number of cases resulting in an increased range of applicability in order to develop design tools and predictive capability for analysis and design. The analysis and results of the numerical modeling, laboratory modeling, and field data provide a process-based method for understanding how structure geometry affects flow characteristics, scour development, fish passage, water delivery, and overall structure stability. Results of the numerical modeling allow designers to utilize results of the analysis to determine the appropriate geometry for generating desirable flow parameters. The end product of this research will develop tools and guidelines for more robust structure design or retrofits based upon predictable engineering and hydraulic performance criteria. ?? 2009 ASCE.
Blodgett, J.C.; Stiehr, Patrick Lenard
1974-01-01
Inundation of State Highway 162 across Butte Basin at the latitude of Butte City results from overland floodflow from the Sacramento River and flooding on Butte Creek. Flooding of Butte Basin from the Sacramento River will occur whenever flow in the main channel at Butte City exceeds 90,000 cubic feet per second (2550 cubic metres per second), a discharge with a recurrence interval of about 3 years. The distribution of floodflow across the basin is not uniform. During the flood of January 24, 1970, 84 percent of the total discharge resulted from overland flow from the Sacramento River and 16 percent from flooding on Butte Creek. When flooding in Butte Basin is severe enough to affect State Highway 162, overflow across the road first occurs between bridges 11-21 and 11-22. The construction of bridges or culverts at two locations between bridges 11-21 and 11-22 would increase the period of time that the road is usable. Analysis of the present roadway, bridge geometry, and ground elevations adjacent to the roadway indicates that backwater is less than 0.6 foot (0.2 metre) for flows of the magnitude experienced during the flood of January 24, 1970. The concurrent maximum velocity of flow at the bridges is 6.8 feet per second (2.1 metres per second). Part of the backwater is caused by ground elevations adjacent to the roadway that are, at many locations, higher than the road crown. If the roadway embankment were raised to prevent overtopping by a flood equivalent to that of January 24, 1970, without increasing the capacity or number of the bridges, backwater greater than 0.5 foot (0.2 metre) would result upstream from 6 of the 15 bridges on State Highway 162, and velocities would be excessive. Additional bridge openings to discharge a total of 37,800 cubic feet per second (1070 cubic metres per second) would be required for at least six locations if backwater and velocity were to be kept to levels similar to those observed for present conditions. During the flood of
NASA Astrophysics Data System (ADS)
Chaanda, Mohammed S.; Jerrett, Rhodri; Grimes, Stephen T.; Price, Gregory D.; Anderson, Mark
2014-05-01
The Petrockstow and Bovey basins are two similar pull apart (strike slip) basins belonging to the Sticklepath - Lustleigh Fault Zone (SLFZ) in Devon, SW England. The SLFZ is one of the several faults on the Cornubian Peninsula and may be linked to Variscan structures rejuvenated in Palaeogene times. The bulk of the basins' fill consists of clays, silts, lignites and sands of Palaeogene age, comparable to the Lough Neagh Basin (Northern Ireland), which is also thought to be part of the SLFZ. The greater part of the British Isles was a land area throughout the Palaeogene. The basin-fills therefore, provide rare, potentially expanded sections through the Palaeocene Eocene Thermal Maximum (PETM), and the Eocene-Oligocene (Oi-1) cooling event in the U.K. Facies analysis has been undertaken on sediments of the Petrockstow and Bovey basins in order to provide a tectonic and palaeoenvironmental context for palaeoclimate reconstructions using palynology, organic geochemistry Methylation Branched Tetraethers/Cyclisation Branched Tetraethers and carbon isotope analyses which have identified the Carbon Isotope Excursion (CIE) associated with the PETM. The following lithofacies types from two boreholes from the Petrockstow Basin (boreholes 1A and 1B) and from outcrop exposed in the Bovey Basin. The lithofacies identified are (a): Silty clay; (b): Red mottled and sideritic clay; (c): laminated silty clay; (d): Minor sand and gravel; (e): Major coarse sand and granules and (f): Lignite. Our new facies model involves: firstly Sand filled fluvial channels, secondly a lake with ready supply of organic debris, and thirdly a lake prone to drying-out. The abrupt transition from sand filled fluvial channels to Lake Facies is coincident with the recognition of the CIE. The possible effect of the Oi-1 glaciation may be linked to the third phase of a lake prone to drying-out facies which is ambiguous in the Bovey Basin. Repeated sub aerial exposure suggests that the lakes present in both
Xie, Ying; Li, Xuyong; Wang, Huiliang; Li, Wenzan
2013-01-01
The analysis of river pollution and assessment of spatial and temporal variation in hydrochemistry are essential to river water pollution control in the context of rapid economic growth and growing pollution threats in China. In this study, we focused on hydrochemical characteristics of the Luanhe River Basin (China) and evaluation of 12 hydrochemical variables obtained from 32 monitoring stations during 2001-2010. In each study year, the streams were monitored in the three hydrological periods (April, August, and October) to observe differences in the impacts of agricultural activity and rainfall pattern. Multivariate statistical methods were applied to the data set, and the river water hydrochemical characteristics were assessed using the water quality identification index (WQIIM). The results showed that parameters had variable contribution to water quality status in different months except for ammonia nitrogen (NH4-N) and total nitrogen (TN), which were the most important parameters in contributing to water quality variations for all three periods. Results of WQIIM revealed that 18 sites were classified as 'meeting standard' while the other 14 sites were classified as 'not meeting standard', with most of the seriously polluted sites located in urban area, mainly due to discharge of wastewater from domestic and industrial sources. Sites with low pollution level were located primarily in smaller tributaries, whereas sites of medium and high pollution levels were in the main river channel and the larger tributaries. Our findings provide valuable information and guidance for water pollution control and water resource management in the Luanhe River Basin. PMID:23508159
An ecometric analysis of the fossil mammal record of the Turkana Basin
Žliobaitė, Indrė; Kaya, Ferhat; Bibi, Faysal; Bobe, René; Leakey, Louise; Leakey, Meave; Patterson, David; Rannikko, Janina; Werdelin, Lars
2016-01-01
Although ecometric methods have been used to analyse fossil mammal faunas and environments of Eurasia and North America, such methods have not yet been applied to the rich fossil mammal record of eastern Africa. Here we report results from analysis of a combined dataset spanning east and west Turkana from Kenya between 7 and 1 million years ago (Ma). We provide temporally and spatially resolved estimates of temperature and precipitation and discuss their relationship to patterns of faunal change, and propose a new hypothesis to explain the lack of a temperature trend. We suggest that the regionally arid Turkana Basin may between 4 and 2 Ma have acted as a ‘species factory’, generating ecological adaptations in advance of the global trend. We show a persistent difference between the eastern and western sides of the Turkana Basin and suggest that the wetlands of the shallow eastern side could have provided additional humidity to the terrestrial ecosystems. Pending further research, a transient episode of faunal change centred at the time of the KBS Member (1.87–1.53 Ma), may be equally plausibly attributed to climate change or to a top-down ecological cascade initiated by the entry of technologically sophisticated humans. This article is part of the themed issue ‘Major transitions in human evolution’. PMID:27298463
Regional L-Moment-Based Flood Frequency Analysis in the Upper Vistula River Basin, Poland
NASA Astrophysics Data System (ADS)
Rutkowska, A.; Żelazny, M.; Kohnová, S.; Łyp, M.; Banasik, K.
2016-05-01
The Upper Vistula River basin was divided into pooling groups with similar dimensionless frequency distributions of annual maximum river discharge. The cluster analysis and the Hosking and Wallis (HW) L-moment-based method were used to divide the set of 52 mid-sized catchments into disjoint clusters with similar morphometric, land use, and rainfall variables, and to test the homogeneity within clusters. Finally, three and four pooling groups were obtained alternatively. Two methods for identification of the regional distribution function were used, the HW method and the method of Kjeldsen and Prosdocimi based on a bivariate extension of the HW measure. Subsequently, the flood quantile estimates were calculated using the index flood method. The ordinary least squares (OLS) and the generalised least squares (GLS) regression techniques were used to relate the index flood to catchment characteristics. Predictive performance of the regression scheme for the southern part of the Upper Vistula River basin was improved by using GLS instead of OLS. The results of the study can be recommended for the estimation of flood quantiles at ungauged sites, in flood risk mapping applications, and in engineering hydrology to help design flood protection structures.
Systemic analysis of desertification processes taking place in the Limpopo river basin
NASA Astrophysics Data System (ADS)
Messina, Mario; Attorre, Fabio; Vitale, Marcello
2016-04-01
Desertification and land degradation are phenomena that ranks among the greatest environmental challenges of our time. Desertification is a global issue, with serious implications worldwide for biodiversity, socio-economic stability and sustainable development. Biophysical indicators of land degradation and desertification, like Net Primary Productivity (NPP) and Total Ecosystem Respiration (Reco) were provided by remote sensing technology (MODIS). The study aims to evaluate the dynamical changes of NPP and Reco in the Limpopo river basin, a Southern African region that includes, Botswana, Mozambique, South Africa and Zimbabwe, during the time period 2001-2010. In particular, the relations between NPP, Reco, environmental, physiological and land use parameters have been widely investigated through the application of a new and powerful statistical classifier, the Random Forest Analysis (RFA), and a general non-linear model, the Response Surface Regression Model (GRM). RFA highlighted that Temperature is one of the most important predictors affecting NPP and Reco in the Limpopo river basin. Conversely, other environmental parameters like, Precipitation, Evapotranspiration and Vegetation cover rarely influence NPP and Reco. Our results provide information on desertification and land degradation phenomena and a first step for identifying practices to mitigate their negative impacts. However, it must be taken into account that NPP and Reco depend by a multitude of factors (e.g. human activities, socio-economic policies) and can vary in relation to spatial and temporal scale. In order to achieve a better understanding of land degradation and desertification processes, land use and socio-economic variables should be considered.
NASA Astrophysics Data System (ADS)
Li, Xian; Shu, Longcang; Liu, Lihong; Yin, Dan; Wen, Jinmei
2012-06-01
Jinci Spring in Shanxi, north China, is a major local water source. It dried up in April 1994 due to groundwater overexploitation. The groundwater system is complex, involving many nonlinear and uncertain factors. Artificial neural network (ANN) models are statistical techniques to study parameter nonlinear relationships of groundwater systems. However, ANN models offer little explanatory insight into the mechanisms of prediction models. Sensitivity analysis can overcome this shortcoming. In this study, a back-propagation neural network model was built based on the relationship between groundwater level and its sensitivity factors in Jinci Spring Basin; these sensitivity factors included precipitation, river seepage, mining drainage, groundwater withdrawals and lateral discharge to the associated Quaternary aquifer. All the sensitivity factors were analyzed with Garson's algorithm based on the connection weights of the neural network model. The concept of "sensitivity range" was proposed to describe the value range of the input variables to which the output variables are most sensitive. The sensitivity ranges were analyzed by a local sensitivity approach. The results showed that coal mining drainage is the most sensitive anthropogenic factor, having a large effect on groundwater level of the Jinci Spring Basin.
An ecometric analysis of the fossil mammal record of the Turkana Basin.
Fortelius, Mikael; Žliobaitė, Indrė; Kaya, Ferhat; Bibi, Faysal; Bobe, René; Leakey, Louise; Leakey, Meave; Patterson, David; Rannikko, Janina; Werdelin, Lars
2016-07-01
Although ecometric methods have been used to analyse fossil mammal faunas and environments of Eurasia and North America, such methods have not yet been applied to the rich fossil mammal record of eastern Africa. Here we report results from analysis of a combined dataset spanning east and west Turkana from Kenya between 7 and 1 million years ago (Ma). We provide temporally and spatially resolved estimates of temperature and precipitation and discuss their relationship to patterns of faunal change, and propose a new hypothesis to explain the lack of a temperature trend. We suggest that the regionally arid Turkana Basin may between 4 and 2 Ma have acted as a 'species factory', generating ecological adaptations in advance of the global trend. We show a persistent difference between the eastern and western sides of the Turkana Basin and suggest that the wetlands of the shallow eastern side could have provided additional humidity to the terrestrial ecosystems. Pending further research, a transient episode of faunal change centred at the time of the KBS Member (1.87-1.53 Ma), may be equally plausibly attributed to climate change or to a top-down ecological cascade initiated by the entry of technologically sophisticated humans.This article is part of the themed issue 'Major transitions in human evolution'. PMID:27298463
NASA Technical Reports Server (NTRS)
Beam, R. M.; Warming, R. F.; Yee, H. C.
1981-01-01
Implicit, noniterative, finite difference schemes were recently developed by several authors for multidimensional systems of nonlinear hyperbolic partial differential equations. When applied to linear model equations with periodic boundary conditions those schemes are unconditionally stable (A-stable). As applied in practice the algorithms often face a severe time step restriction. A major source of the difficulty is the treatment of the numerical boundary conditions. One conjecture was that unconditional stability requires implicit numerical boundary conditions. An apparent counter example was the space time extrapolation considered by Gustafsson, Kreiss, and Sunstrom. Spatial (implicit) and space time (explicit) extrapolation using normal mode analysis for a finite and infinite number of spatial mesh intervals are examined. The results indicate that for unconditional stability with a finite number of spatial mesh intervals, the numerical boundary conditions must be implicit.
Identifying the causes of water crises: A configurational frequency analysis of 22 basins world wide
NASA Astrophysics Data System (ADS)
Srinivasan, V.; Gorelick, S.; Lambin, E.; Rozelle, S.; Thompson, B.
2010-12-01
Freshwater "scarcity" has been identified as being a major problem world-wide, but it is surprisingly hard to assess if water is truly scarce at a global or even regional scale. Most empirical water research remains location specific. Characterizing water problems, transferring lessons across regions, to develop a synthesized global view of water issues remains a challenge. In this study we attempt a systematic understanding of water problems across regions. We compared case studies of basins across different regions of the world using configurational frequency analysis. Because water crises are multi-symptom and multi-causal, a major challenge was to categorize water problems so as to make comparisons across cases meaningful. In this study, we focused strictly on water unsustainability, viz. the inability to sustain current levels of the anthropogenic (drinking water, food, power, livelihood) and natural (aquatic species, wetlands) into the future. For each case, the causes of three outcome variables, groundwater declines, surface water declines and aquatic ecosystem declines, were classified and coded. We conducted a meta-analysis in which clusters of peer-reviewed papers by interdisciplinary teams were considered to ensure that the results were not biased towards factors privileged by any one discipline. Based on our final sample of 22 case study river basins, some clear patterns emerged. The meta-analysis suggests that water resources managers have long overemphasized the factors governing supply of water resources and while insufficient attention has been paid to the factors driving demand. Overall, uncontrolled increase in demand was twice as frequent as declines in availability due to climate change or decreased recharge. Moreover, groundwater and surface water declines showed distinct causal pathways. Uncontrolled increases in demand due to lack of credible enforcement were a key factor driving groundwater declines; while increased upstream abstractions
Tandon, K.; Tuncay, K.; Hubbard, K.; Comer, J.; Ortoleva, P.
2004-01-01
A data assimilation approach is demonstrated whereby seismic inversion is both automated and enhanced using a comprehensive numerical sedimentary basin simulator to study the physics and chemistry of sedimentary basin processes in response to geothermal gradient in much greater detail than previously attempted. The approach not only reduces costs by integrating the basin analysis and seismic inversion activities to understand the sedimentary basin evolution with respect to geodynamic parameters-but the technique also has the potential for serving as a geoinfomatics platform for understanding various physical and chemical processes operating at different scales within a sedimentary basin. Tectonic history has a first-order effect on the physical and chemical processes that govern the evolution of sedimentary basins. We demonstrate how such tectonic parameters may be estimated by minimizing the difference between observed seismic reflection data and synthetic ones constructed from the output of a reaction, transport, mechanical (RTM) basin model. We demonstrate the method by reconstructing the geothermal gradient. As thermal history strongly affects the rate of RTM processes operating in a sedimentary basin, variations in geothermal gradient history alter the present-day fluid pressure, effective stress, porosity, fracture statistics and hydrocarbon distribution. All these properties, in turn, affect the mechanical wave velocity and sediment density profiles for a sedimentary basin. The present-day state of the sedimentary basin is imaged by reflection seismology data to a high degree of resolution, but it does not give any indication of the processes that contributed to the evolution of the basin or causes for heterogeneities within the basin that are being imaged. Using texture and fluid properties predicted by our Basin RTM simulator, we generate synthetic seismograms. Linear correlation using power spectra as an error measure and an efficient quadratic
Analysis of potential climate change impact on mean flow in Somes, river basin, Romania
NASA Astrophysics Data System (ADS)
Mic, Rodica Paula; Corbuş, Ciprian
2014-05-01
This paper presents the results obtained by the National Institute of Hydrology and Water Management (NIHWM) in collaboration with the Swedish Meteorological and Hydrological Institute (SMHI) within the ECLISE project ("Enabling CLimate Information Services for Europe"). In order to estimate the modifications due by the climate change on the mean flow of the Somes river basin in the time horizon 2021 - 2050 the hydrological model WATBAL was used, a water balance model with monthly time step, using as input data series of monthly precipitation and mean monthly temperature. These series resulted from data processing of climate projections obtained by four regional climate models: CNRM_RM5.1_ARPEGE (A), HC_HadRM3Q0_HadCM3Q0 (B), SMHI_RCA3_BCM (C) and SMHI_RCA3_ECHAM5 (D). WATBAL model parameters were calibrated by the flow simulation in 33 analysed cross-sections from Somes river basin using as input data the monthly precipitation and mean monthly temperatures recorded at weather stations located into the area, during 1971-2000, considered as reference period. Hydrological simulation was performed taking into account two scenarios: Scenario 0, in which mean monthly discharge was computed for the reference period, considering the meteorological inputs simulated with climate models, and Scenario 1, which suppose the simulation of mean monthly discharge for the next period 2021-2050, with the same hydrological model, considering as inputs the climate change projections. Comparative analysis of water flow simulations in Somes river basin, regarding the regime of multi-annual mean monthly, seasonal and annual discharges, for the reference period and for the next period have been carried out. From the analysis performed in this study resulted that the variation of the multi-annual monthly mean discharges based on the 4 climate models considered in the assumption of climate change (period 2021-2050) compared to the current flowing regime (period 1971-2000) is often
NASA Astrophysics Data System (ADS)
Velpuri, N. M.; Senay, G. B.; Verdin, J. P.
2014-12-01
Change in storage is an important component of water cycle that is often ignored in large-scale hydrologic studies due to limited data and difficulty in measurement. For the first time, this study quantifies and inter-compares storage changes in major river basins of the world. Gravity Recovery and Climate Experiment (GRACE) monthly mass deviation in storage (MDS) data over 2003-2013 is used to compute monthly, annual and long-term change in storage (ΔS) for 51 major river basins of the world (> 200,000 km2). For each river basin, GRACE ΔS is analyzed to understand a) temporal variability in ΔS b) magnitude of ΔS at annual and decadal time scales and c) duration of storage cycle (time taken by a basin in months to return to initial storage condition). This study identified that 11, 33 and 7 out of 51 basins showed high, medium and low month to month variability in storage changes, respectively. Compared to basin precipitation, 48 out of 51 river basins showed storage to be considerable (5 - 35% of basin annual precipitation). Only 3 basins (Irrawaddy, St. Lawrence, and Brahmaputra) showed minimum variability in storage (< 5%). At long-term (decadal) time-scales, all the 51 river basins showed negligible storage changes (< 0.5%). This result emphasizes the fact that change in storage, ΔS is substantial at monthly and annual time scales but can be ignored over a decadal time scale. Analysis of storage cycle for each basin revealed that a basin can take anywhere from 5 to 12 months to restore itself. While, 14 out of 51 basins showed biannual storage cycle (≤ 6 months), six basins (Zambezi, Mekong, Orinoco, Tocantins, and Amazon) showed annual storage cycle of 12 months. Our results indicate that most basins within the tropics show positive correlation with precipitation indicating that precipitation is the main driver of storage. On the other hand, ΔS in the basins located in the higher latitudes mostly show negative correlation with precipitation. This study
de Foy, B.; Fast, Jerome D.; Paech, S. J.; Phillips, D.; Walters, J. T.; Coulter, Richard L.; Martin, Tim J.; Pekour, Mikhail S.; Shaw, William J.; Kastendeuch, P. P.; Marley, Nancy A.; Retama, A.; Molina, Luisa T.
2008-03-03
The MILAGRO field campaign was a multi-agency international collaborative project to evaluate the regional impacts of the Mexico City air pollution plume as a means of understanding urban impacts on the global climate. Mexico City lies on an elevated plateau with mountains on three sides and has complex mountain and surface-driven wind flows. This paper asks what the wind transport was in the basin during the field campaign and how representative it was of the climatology. Surface meteorology and air quality data, radiosoundings and radar wind profiler data were collected at sites in the basin and its vicinity. Cluster analysis is used to identify the dominant wind patterns both during the campaign and within the past 10 years of operational data from the warm dry season. Our analysis shows that March 2006 was representative of typical flow patterns experienced in the basin. Six episode types were identified for the basin scale circulation providing a way of interpreting atmospheric chemistry and particulate data collected during the campaign. Decoupling between surface winds and those aloft had a strong influence in leading to convection and poor air quality episodes. Hourly characterisation of wind circulation during the MILAGRO, MCMA-2003 and IMADA field campaigns will enable the comparisons of similar air pollution episodes and the evaluation of the impact of wind transport on measurements of the atmospheric chemistry taking place in the basin.
NASA Astrophysics Data System (ADS)
McCrory, Patricia A.
1989-03-01
Geohistory analysis of Neogene Humboldt basin strata provides important constraints for hypotheses of the tectonic evolution of the southern Cascadia subduction margin, leading up to the arrival of the Mendocino triple junction. This analysis suggests that the tectonic evolution of the Humboldt basin area was dominated by coupling between the downgoing Juan de Fuca plate and the continental margin. This coupling is reflected in the timing of major hiatuses within the basin sedimentary sequence and margin uplift and subsidence which occur during periods of tectonic plate adjustment. Stratigraphic evidence indicates that Humboldt basin originated at the base of the continental slope in early Miocene time. Syndepositional uplift of basin strata began in the late Pliocene and was both thermal isostatic and tectonic in origin. Isostatic uplift was a function of an increasingly more buoyant slab being subducted, whereas tectonic uplift was due to imbricated thrusting of the accretionary complex and underplating of offscraped sediment during subduction. A component of margin uplift is postulated to have been caused by a change in the rate of convergence between the Juan de Fuca and North American plates. Coeval with late Pliocene uplift documented onshore was a sharp decrease in covergence rate ˜3 Ma. A reduction in rate of tectonic uplift, observed in the Eel River section, in early Pleistocene time was coeval with a marked increase in relative motion parallel to the continental margin. This localized subsidence may have been caused by syndepositional folding.
Development of a numerical model for vehicle-bridge interaction analysis of railway bridges
NASA Astrophysics Data System (ADS)
Kim, Hee Ju; Cho, Eun Sang; Ham, Jun Su; Park, Ki Tae; Kim, Tae Heon
2016-04-01
In the field of civil engineering, analyzing dynamic response was main concern for a long time. These analysis methods can be divided into moving load analysis method and moving mass analysis method, and formulating each an equation of motion has recently been studied after dividing vehicles and bridges. In this study, the numerical method is presented, which can consider the various train types and can solve the equations of motion for a vehicle-bridge interaction analysis by non-iteration procedure through formulating the coupled equations for motion. Also, 3 dimensional accurate numerical models was developed by KTX-vehicle in order to analyze dynamic response characteristics. The equations of motion for the conventional trains are derived, and the numerical models of the conventional trains are idealized by a set of linear springs and dashpots with 18 degrees of freedom. The bridge models are simplified by the 3 dimensional space frame element which is based on the Euler-Bernoulli theory. The rail irregularities of vertical and lateral directions are generated by PSD functions of the Federal Railroad Administration (FRA).
Sampling and Analysis Plan for canister liquid and gas sampling at 105-KW fuel storage basin
Harris, R.A.; Green, M.A.; Makenas, B.J.; Trimble, D.J.
1995-03-01
This Sampling and Analysis Plan (SAP) details the sampling and analyses to be performed on fuel canisters transferred to the Weasel Pit of the 105-KW fuel storage basin. The radionuclide content of the liquid and gas in the canisters must be evaluated to support the shipment of fuel elements to the 300 Area in support of the fuel characterization studies (Abrefah, et al. 1994, Trimble 1995). The following sections provide background information and a description of the facility under investigation, discuss the existing site conditions, present the constituents of concern, outline the purpose and scope of the investigation, outline the data quality objectives (DQO), provide analytical detection limit, precision, and accuracy requirements, and address other quality assurance (QA) issues.
Vegetation analysis in the Laramie Basin, Wyoming from ERTS-1 imagery
NASA Technical Reports Server (NTRS)
Evans, M. A.; Redfern, F. R.
1973-01-01
The author has identified the following significant results. The application of ERTS-1 imagery to vegetation mapping and identification was tested and confirmed by field checking. ERTS-1 imagery interpretation and density contour mapping allows definition of minute vegetation features and estimation of vegetative biomass and species composition. Large- and small-scale vegetation maps were constructed for test areas in the Laramie Basin and Laramie mountains of Wyoming. Vegetative features reflecting grazing intensity, moisture availability, changes within the growing season, cutting of hay crops, and plant community constituents in forest and grassland are discussed and illustrated. Theoretical considerations of scattering, sun angle, slope, and instrument aperture upon image and map resolution were investigated. Future suggestions for applications of ERTS-1 data to vegetative analysis are included.
Shedrow, C.B.
1999-11-29
The Safety Analysis Report documents the safety authorization basis for the Receiving Basin for Offsite Fuels (RBOF) and the Resin Regeneration Facility (RRF) at the Savannah River Site (SRS). The present mission of the RBOF and RRF is to continue in providing a facility for the safe receipt, storage, handling, and shipping of spent nuclear fuel assemblies from power and research reactors in the United States, fuel from SRS and other Department of Energy (DOE) reactors, and foreign research reactors fuel, in support of the nonproliferation policy. The RBOF and RRF provide the capability to handle, separate, and transfer wastes generated from nuclear fuel element storage. The DOE and Westinghouse Savannah River Company, the prime operating contractor, are committed to managing these activities in such a manner that the health and safety of the offsite general public, the site worker, the facility worker, and the environment are protected.
Hydropower potential mapping in mountain basins by high-resolution hydrological and GIS analysis
NASA Astrophysics Data System (ADS)
Claps, P.; Gallo, E.; Ganora, D.; Laio, F.; Masoero, A.
2013-12-01
Even in regions with mature hydropower development, needs for stable renewable power sources suggest to revise plans of exploitation of water resources, in compliance to the framework of international and national environmental regulations. This goal requires high-resolution hydrological analysis, that allows to : i) comply with the effects of existing hydropower plants or of other types of water withdrawals; ii) to assist the planner to figure out potential of new plants with still high marginal efficiency; iii) to assist the regulator in the process of comparing projects based on different solutions and different underlying hydrologic estimation methods. Flow duration curves (FDC) are the tool usually adopted to represent water availability and variability for hydropower purposes. They are usually determined in ungauged basins by means of regional statistical analysis. For this study, a 'spatially smooth' regional estimation method (SSEM) has been developed for FDC estimation, with some evolutions from a previous version: i) the method keeps the estimates of mean annual runoff congruent in the confluences by considering only raster-summable explanatory variables; ii) the presence of existing reservoirs and hydropower plants is taken into account by restoring the ';natural' statistics of the curve. The SSEM reconstructs the the FDC in ungauged basins using its L-moments from regressions on geomorphoclimatic descriptors. Relations are obtained on more than 100 gauged basins located in Northwestern Italy. To support the assessment of residual hydropower potential on two specific mountain watersheds the model has been applied extensively (Hi-Res) by mapping the estimated mean flow for each pixel of a DEM-derived river network raster model. 25000 sections were then identified over the network extracted from a 50m-resolution DTM. Spatial algorithms and data management were developed using Free&OpenSource Software (FOSS) (GRASS GIS and PostgreSQL/PostGIS), with the
NASA Astrophysics Data System (ADS)
Klimczak, Christian; Watters, Thomas R.; Ernst, Carolyn M.; Freed, Andrew M.; Byrne, Paul K.; Solomon, Sean C.; Blair, David M.; Head, James W.
2012-09-01
Since its insertion into orbit about Mercury in March 2011, the MESSENGER spacecraft has imaged most previously unseen regions of the planet in unprecedented detail, revealing extensive regions of contiguous smooth plains at high northern latitudes and surrounding the Caloris basin. These smooth plains, thought to be emplaced by flood volcanism, are populated with several hundred ghost craters and basins, nearly to completely buried impact features having rims for which the surface expressions are now primarily rings of deformational landforms. Associated with some ghost craters are interior groups of graben displaying mostly polygonal patterns. The origin of these graben is not yet fully understood, but comparison with numerical models suggests that the majority of such features are the result of stresses from local thermal contraction. In this paper, we highlight a previously unreported category of ghost craters, quantify extensional strains across graben-bearing ghost craters, and make use of graben geometries to gain insights into the subsurface geology of smooth plains areas. In particular, the style and mechanisms of graben development imply that flooding of impact craters and basins led to substantial pooling of lavas, to thicknesses of ˜1.5 km. In addition, surface strains derived from groups of graben are generally in agreement with theoretically and numerically derived strains for thermal contraction.
3D Numerical Analysis of Flow Control on Wind Turbine Blades
NASA Astrophysics Data System (ADS)
Sahni, Onkar; Karaismail, Ertan
2011-11-01
Wind turbine blades are exposed to unsteady and spatially-varying loadings in a real field. These loadings result in fluctuating structural forces which in turn lead to failure of blades as well as gearbox. In this study, we perform numerical analysis of flow over a wind turbine blade placed in a wind tunnel; where dynamic motions are imposed to the blade in order to emulate scenarios observed in a real field. Furthermore, we also study the effect of active flow control (via synthetic-jets) on unsteady aerodynamic characteristics of the blade under dynamic motions; the idea is to be able to control aerodynamic loads and mitigate failures. Numerical analysis is based on massively parallel simulations using hybrid turbulence models. Comparisons with experimental data will also be included.
NASA Astrophysics Data System (ADS)
Farhoudi, Gh.; Samiee Ardabili, J.
2009-04-01
The Kaftar lake basin is located in the High Zagros Mountain Belt in the southwest of Namdan plain in the northern part of Fars province (Iran). The studied area surrounded by Gandboi ridge with E-W trend in the north and NW-SE trended Bareaftab anticline in the south. The main faults in the studied area are Moosakhani and Korchool (Kaftar) thrust faults, which are recorded in the Iran aeromagnetic map with T-12 and T-46, respectively. These faults are on the south eastern edge of the Zagros thrust system. With this study, in which we have used automatic lineament extraction algorithm from multi sources, high resolution morphometric data, analysis of morphotectonic elements based on high spatial resolution satellite imagery and digital elevation model, and field study. We have tried to detect the tectonic activities and understand the origin and evolution of the Kaftar lake basin. Based on analysis of existing data and results of this study, Gandboi ridge is a syncline with complex topography uplifted and rotated by Korchool fault. Bareaftab anticline, which is located in the hanging wall of Moosakhani fault, is a fault propagation fold and has also been formed by this fault. Based on the bed rock map of Namdan plain,The Kaftar lake has been produced in a depression within folds caused by Korchool fault. The high tectonic and karstic activities as well as the fact that the lake is not salty, indicatig a drain of the lake, proved that the Kaftar lake is a part of a polje of the karst system of Namdan plain.
Flood Frequency Analysis For Partial Duration Series In Ganjiang River Basin
NASA Astrophysics Data System (ADS)
zhangli, Sun; xiufang, Zhu; yaozhong, Pan
2016-04-01
Accurate estimation of flood frequency is key to effective, nationwide flood damage abatement programs. The partial duration series (PDS) method is widely used in hydrologic studies because it considers all events above a certain threshold level as compared to the annual maximum series (AMS) method, which considers only the annual maximum value. However, the PDS has a drawback in that it is difficult to define the thresholds and maintain an independent and identical distribution of the partial duration time series; this drawback is discussed in this paper. The Ganjiang River is the seventh largest tributary of the Yangtze River, the longest river in China. The Ganjiang River covers a drainage area of 81,258 km2 at the Wanzhou hydrologic station as the basin outlet. In this work, 56 years of daily flow data (1954-2009) from the Wanzhou station were used to analyze flood frequency, and the Pearson-III model was employed as the hydrologic probability distribution. Generally, three tasks were accomplished: (1) the threshold of PDS by percentile rank of daily runoff was obtained; (2) trend analysis of the flow series was conducted using PDS; and (3) flood frequency analysis was conducted for partial duration flow series. The results showed a slight upward trend of the annual runoff in the Ganjiang River basin. The maximum flow with a 0.01 exceedance probability (corresponding to a 100-year flood peak under stationary conditions) was 20,000 m3/s, while that with a 0.1 exceedance probability was 15,000 m3/s. These results will serve as a guide to hydrological engineering planning, design, and management for policymakers and decision makers associated with hydrology.
Regional flood frequency analysis for the Gan-Ming River basin in China
NASA Astrophysics Data System (ADS)
Jingyi, Zhang; Hall, M. J.
2004-08-01
A regionalised relationship to estimate flood magnitudes for ungauged and poorly gauged catchments can be established using regional flood frequency analysis. The geographical approach (Residuals method), Ward's cluster method, the Fuzzy c-means method and a Kohonen neural network were applied to 86 sites in the Gan River Basin of Jiangxi Province and the Ming River Basin of Fujian Province in the southeast of China to delineate homogeneous regions based on site characteristics. Similar groupings of sites into sub-regions were obtained from all but the Residuals method. Since the Kohonen neural network can be employed to identify the number of sub-regions as well as the allocation of sites to sub-regions, this method is to be preferred over Ward's method and the Fuzzy c-means approach. For each sub-region, growth curves must be constructed and the value of an index flood must be related to catchment characteristics. The regional L-moment algorithm may be used to advantage both to identify an appropriate underlying frequency distribution and to construct sub-regional growth curves. However, the membership levels produced by the Fuzzy c-means method may also be used as weights to derive a regional at-site growth curve from those of all the sub-regions. The latter method is likely to be most useful where the sub-regional growth curves are of strongly contrasting shape. An index flood may be related to catchment characteristics using Multiple Linear Regression Analysis, but application to the Gan-Ming data demonstrates that estimates with lower standard errors of estimate can be produced using an artificial neural network (ANN). However, in order to apply such ANNs, sufficient sites must be available so that enough processing elements can be employed without impairing the ability of the network to generalise outside the training data set.
Petrophysical Analysis and Geographic Information System for San Juan Basin Tight Gas Reservoirs
Martha Cather; Robert Lee; Robert Balch; Tom Engler; Roger Ruan; Shaojie Ma
2008-10-01
The primary goal of this project is to increase the availability and ease of access to critical data on the Mesaverde and Dakota tight gas reservoirs of the San Juan Basin. Secondary goals include tuning well log interpretations through integration of core, water chemistry and production analysis data to help identify bypassed pay zones; increased knowledge of permeability ratios and how they affect well drainage and thus infill drilling plans; improved time-depth correlations through regional mapping of sonic logs; and improved understanding of the variability of formation waters within the basin through spatial analysis of water chemistry data. The project will collect, integrate, and analyze a variety of petrophysical and well data concerning the Mesaverde and Dakota reservoirs of the San Juan Basin, with particular emphasis on data available in the areas defined as tight gas areas for purpose of FERC. A relational, geo-referenced database (a geographic information system, or GIS) will be created to archive this data. The information will be analyzed using neural networks, kriging, and other statistical interpolation/extrapolation techniques to fine-tune regional well log interpretations, improve pay zone recognition from old logs or cased-hole logs, determine permeability ratios, and also to analyze water chemistries and compatibilities within the study area. This single-phase project will be accomplished through four major tasks: Data Collection, Data Integration, Data Analysis, and User Interface Design. Data will be extracted from existing databases as well as paper records, then cleaned and integrated into a single GIS database. Once the data warehouse is built, several methods of data analysis will be used both to improve pay zone recognition in single wells, and to extrapolate a variety of petrophysical properties on a regional basis. A user interface will provide tools to make the data and results of the study accessible and useful. The final deliverable
NASA Astrophysics Data System (ADS)
Senay, G. B.; Velpuri, N. M.; Bohms, S.; Demissie, Y.; Gebremichael, M.
2014-12-01
The Nile River is the longest in the world with a length of 6,800 km. However, the contrast between the length of the river or the size of the basin and the comparatively small volume of basin runoff generated is a unique feature of the Nile Basin. Due to non-availability of in-situ hydrologic data, we do not clearly understand the spatial distribution of hydrologic sources and sinks and how much they control input-output dynamics? In this study, we integrated satellite-derived precipitation, and modeled evapotranspiration data (2000-2012) to describe spatial variability of hydrologic sources and sinks in the Nile Basin. We also used long-term gridded runoff and river discharge data (1869-1984) to understand the discrepancy in the observed and expected flow along the Nile River. Results indicate that over 2000-2012 period, 4 out of 11 countries (Ethiopia, Tanzania, Kenya, and Uganda) in the Nile basin showed a positive water balance while three downstream countries (South Sudan, Sudan, and Egypt) showed a negative balance. The top three countries that contribute most to the flow are Ethiopia, Tanzania and Kenya. The study revealed that ~85% of the runoff generated in the Equatorial region is lost in an inter-station basin that includes the Sudd wetlands in South Sudan; this proportion is higher than the reported loss of 50% at the Sudd wetlands alone. The loss in runoff and flow volume at different sections of the river tend to be more than what can be explained by evaporation losses, suggesting a potential recharge to deeper aquifers that are not connected to the Nile channel systems. On the other hand, we also found that the expected average annual Nile flow at Aswan is larger (97 km3) than the reported amount (84 km3). Gravity Recovery and Climate Experiment (GRACE) mass deviation in storage data analysis showed that at annual time-scales, the Nile Basin shows storage change is substantial while over longer-time periods, it is minimal (<1% of basin precipitation
Nonequilibrium flow computations. I - An analysis of numerical formulations of conservation laws
NASA Technical Reports Server (NTRS)
Liu, Yen; Vinokur, Marcel
1989-01-01
Modern numerical techniques employing properties of flux Jacobian matrices are extended to general, nonequilibrium flows. Generalizations of the Beam-Warming scheme, Steger-Warming and van Leer Flux-vector splittings, and Roe's approximate Riemann solver are presented for 3-D, time-varying grids. The analysis is based on a thermodynamic model that includes the most general thermal and chemical nonequilibrium flow of an arbitrary gas. Various special cases are also discussed.
Nonequilibrium flow computations. 1: An analysis of numerical formulations of conservation laws
NASA Technical Reports Server (NTRS)
Liu, Yen; Vinokur, Marcel
1988-01-01
Modern numerical techniques employing properties of flux Jacobian matrices are extended to general, nonequilibrium flows. Generalizations of the Beam-Warming scheme, Steger-Warming and van Leer Flux-vector splittings, and Roe's approximate Riemann solver are presented for 3-D, time-varying grids. The analysis is based on a thermodynamic model that includes the most general thermal and chemical nonequilibrium flow of an arbitrary gas. Various special cases are also discussed.
Numerical Analysis of Large Telescopes in Terms of Induced Loads and Resulting Geometrical Stability
NASA Astrophysics Data System (ADS)
Upnere, S.; Jekabsons, N.; Joffe, R.
2013-03-01
Comprehensive numerical studies, involving structural and Computational Fluid Dynamics (CFD) analysis, have been carried out at the Engineering Research Institute "Ventspils International Radio Astron- omy Center" (VIRAC) of the Ventspils University College to investigate the gravitational and wind load effects on large, ground-based radio tele- scopes RT-32 performance. Gravitational distortions appear to be the main limiting factor for the reflector performance in everyday operation. Random loads caused by wind gusts (unavoidable at zenith) contribute to the fatigue accumulation.
Design analysis for the control and drive retrofit of a numerically controlled lathe
Cotter, S.L.
1980-01-01
A system approach to the retrofit of a numerically controlled two-axis lathe was taken to identify component function and interrelation. The dynamic system of the motor and machine was modeled and parameter identification experiments were done. This model, in state equation form, was used with the parameters data as the basis of a digital simulation of the system. From this and further analysis of the control characteristics, recommendations for component selection were presented.
NASA Astrophysics Data System (ADS)
Ohchi, Masashi; Furukawa, Tatsuya; Tanaka, Shin-Ichiro
Among several numerical methods, a Finite Element Method (FEM) has been adopted in various engineering problems. In such a background, it is necessary to instruct university students in the numerical analysis. The authors have designed and implemented the numerical analysis education support system for learning electromagnetic fields with Graphical User Interface (GUI) based on the server-client model using Java. In the paper, a feasibility study on the student laboratory class in the third year is described.
Sampling and analysis plan for sludge located in fuel storage canisters of the 105-K east basin
Baker, R.B., Westinghouse Hanford
1996-05-20
This Sampling and Analysis Plan (SAP) provides direction for the first sampling of sludge from the K East Basin spent fuel canisters. The specially developed sampling equipment used removes representative samples of sludge while maintaining the radioactive sample underwater in the basin pool (equipment is described in WHC-SD-SNF-SDD-004). Included are the basic background logic for sample selection, the overall laboratory analyses required and the laboratory reporting required. These are based on requirements put forth in the data quality objectives (WHC-SD-SNF-DQO-008) established for this sampling and characterization activity.
Sampling and analysis plan for sludge located in fuel storage canisters of the 105-K West basin
Baker, R.B.
1997-04-30
This Sampling and Analysis Plan (SAP) provides direction for the first sampling of sludge from the K West Basin spent fuel canisters. The specially developed sampling equipment removes representative samples of sludge while maintaining the radioactive sample underwater in the basin pool (equipment is described in WHC-SD-SNF-SDD-004). Included are the basic background logic for sample selection, the overall laboratory analyses required and the laboratory reporting required. These are based on requirements put forth in the data quality objectives (WHC-SD-SNF-DQO-012) established for this sampling and characterization activity.
Numerical analysis of stress distribution in embedded highly birefringent PANDA fibers
NASA Astrophysics Data System (ADS)
Lesiak, Piotr; Woliński, Tomasz
2015-09-01
The paper presents numerical analysis compared with experimental data of influence of polymerization shrinkage on highly birefringent (HB) PANDA optical fibers embedded in a composite material. Since polymerization is a chemical process consisting in combining single molecules in a macromolecular compound [1], principal directions of the polymerization shrinkage depend on a number of the composite layers associated with this process. In this paper a detailed analysis of the piezo-optic effects occurring in HB optical fibers before and after the lamination process answers the question to what extent a degree of the material degradation can be properly estimated.
Experimental and Numerical Analysis of Screw Fixation in Anterior Cruciate Ligament Reconstruction
NASA Astrophysics Data System (ADS)
Chizari, Mahmoud; Wang, Bin; Snow, Martyn; Barrett, Mel
2008-09-01
This paper reports the results of an experimental and finite element analysis of tibial screw fixation in anterior cruciate ligament (ACL) reconstruction. The mechanical properties of the bone and tendon graft are obtained from experiments using porcine bone and bovine tendon. The results of the numerical study are compared with those from mechanical testing. Analysis shows that the model may be used to establish the optimum placement of the tunnel in anterior cruciate ligament reconstruction by predicting mechanical parameters such as stress, strain and displacement at regions in the tunnel wall.
Tokurakawa, Masaki; Shirakawa, Akira
2015-10-01
Numerical analysis of fast saturable absorber mode-locked Yb(3+)-doped solid state lasers is reported. The analysis includes a special case in which the spectral bandwidth of the short pulse is larger than the fluorescence bandwidth of the gain material. The relationship between the available shortest pulse duration and modulation depth for a standard bulk and thin disk laser geometries with several gain materials are shown. The characteristic phenomena observed in our previous Kerr-lens mode-locked laser experiments were reproduced in the simulation. PMID:26480142
Sampling and analysis plan for sludge located on the floor and in the pits of the 105-K basins
BAKER, R.B.
1998-11-20
This Sampling and Analysis Plan (SAP) provides direction for the sampling of the sludge found on the floor and in the remote pits of the 105-K Basins to provide: (1) basic data for the sludges that have not been characterized to-date and (2) representative Sludge material for process tests to be made by the SNF Project/K Basins sludge treatment process subproject. The sampling equipment developed will remove representative samples of the radioactive sludge from underwater at the K Basins, depositing them in shielded containers for transport to the Hanford Site laboratories. Included in the present document is the basic background logic for selection of the samples to meet the requirements established in the Data Quality Objectives (DQO), HNF-2033, for this sampling activity. The present document also includes the laboratory analyses, methods, procedures, and reporting that will be required to meet the DQO.
NASA Astrophysics Data System (ADS)
Han, Tao; Xie, Yaowen; Jiang, Youyan
2015-12-01
In the paper, the use of 1994 and 2005 Landsat TM data monitors the land use and changes of the Shiyang river basin with remote sensing classification comparison under the support of GIS. The result shows that from 1994 to 2005, the area of farmland and settlement land increased greatly and that of grass and forest reduces obviously in this basin; Minqin which is in the lower reaches of Shiyang river basin has a serious desertification with low grass coverage degradation into desert. With a comprehensive analysis about the driving factors of nature and human, population pressure and irrational use of water resource are the key factors of the Land use change and between the natural factor and human factor, human acts leading role.
Scattering of guided waves from discontinuities in cylinders: Numerical and experimental analysis
NASA Astrophysics Data System (ADS)
Benmeddour, Farouk; Laguerre, Laurent; Treyssède, Fabien
2012-05-01
The aim of this work is to study the fundamental compressional (L(0,1)) Pochhammer-Chree mode interaction with nonaxisymmetric damages in cylinders. To this end, experimental and numerical investigations of non-axisymmetric vertical cracks are considered. A non-contact magnetostrictive device is used for experimental investigations. Magnetostrictive transducers are used to generate and receive compressional guided waves. These are enabled by using an axisymmetric and longitudinal magnetic polarising field. Both, the incident and the reflected signals are acquired by the same receiver which allows a direct calculation of the reflected power flow. Different vertical cracks with various depths milled in steel cylinders are considered. The power flows are compared with those obtained by a three dimensional numerical method. This numerical method is based on a hybrid three dimensional (3D) approach combining the classical finite element (FE) method with the semi-analytical finite element (SAFE) technique. The near field surrounding the damage is analysed with the 3D FE method whereas transparent conditions are applied to the wave guide sections for the far field analysis. These transparent conditions are based on modal expansions on cross-sections. The SAFE technique is used to compute the eigenmodes. Eigenforces and modal power flows are post-processed on a straightforward way. First, the hybrid method is validated with published results in the literature obtained for a free-end cylinder. Finally, numerical and experimental results are compared with success.
Fischetti, Sebastian; Cadonati, Laura; Mohapatra, Satyanarayan R. P.; Healy, James; London, Lionel; Shoemaker, Deirdre
2011-02-15
Recent years have witnessed tremendous progress in numerical relativity and an ever improving performance of ground-based interferometric gravitational wave detectors. In preparation for the Advanced Laser Interferometer Gravitational Wave Observatory (Advanced LIGO) and a new era in gravitational wave astronomy, the numerical relativity and gravitational wave data analysis communities are collaborating to ascertain the most useful role for numerical relativity waveforms in the detection and characterization of binary black hole coalescences. In this paper, we explore the detectability of equal mass, merging black hole binaries with precessing spins and total mass M{sub T}(set-membership sign)[80,350]M{sub {center_dot}}, using numerical relativity waveforms and templateless search algorithms designed for gravitational wave bursts. In particular, we present a systematic study using waveforms produced by the MayaKranc code that are added to colored, Gaussian noise and analyzed with the Omega burst search algorithm. Detection efficiency is weighed against the orientation of one of the black-hole's spin axes. We find a strong correlation between the detection efficiency and the radiated energy and angular momentum, and that the inclusion of the l=2, m={+-}1, 0 modes, at a minimum, is necessary to account for the full dynamics of precessing systems.
NASA Astrophysics Data System (ADS)
Michelioudakis, Dimitrios G.; Hobbs, Richard W.; Caiado, Camila C. S.
2016-04-01
Quantifying the depths of target horizons from seismic reflection data is among the most important aspects of exploration geophysics. In order to constrain these depths we need a reliable and accurate velocity model. Here, we apply Bayesian methods, such as Gaussian process emulators, to estimate the uncertainties of the depths of key horizons near the well DSDP-258 located in the Mentelle Basin, south west of Australia, and compared the results with the drilled core extracted from that well. Eventually, this method will be applied to identify the drilling targets for the International Ocean Discovery Program (IODP), leg 369. The Mentelle Basin is a sparsely explored, deep water sedimentary basin, located between the Naturaliste Plateau and the southern part of the Western Australian Shelf. Its main depocenter, is believed to contain sediments that span from Cretaceous to Holecene, but most importantly it hosts a continuous shale sequence that it is over a kilometer thick, the study of which, is crucial for the correlation between the paleoclimate conditions and the tectonic history of the region. Using two 2D multichannel seismic reflection profiles around the drill site, we generate detailed anisotropic velocity models for the well location in order to construct initially the optimum Pre -- stack time (PSTM) and eventually the Pre - stack depth migrated (PSDM) subsurface images. Moreover, in order to enhance the sub - basalt imaging of the region of interest with the goal to constrain the tectonic models of the area, we apply deterministic deconvolution filters using the source function extracted from our seismic data. The best velocity model created from the initial processing serves as the prior information to the Bayesian model. The final goal is to try to build a multi-layered model of n layers and estimate the zero offset two way time, t0, and the interval velocities,Vi, both for isotropic (Vxi ≈ Vzi) and anisotropic (Vxi ≠ Vzi) cases, in terms of a
Molecular Mapping and Candidate Gene Analysis for Numerous Spines on the Fruit of Cucumber.
Zhang, Shengping; Liu, Shulin; Miao, Han; Wang, Min; Liu, Panna; Wehner, Todd C; Gu, Xingfang
2016-09-01
Number of spines on the fruit is an important quality trait in cucumber. The inheritance and identification of molecular markers for fruit spine density gene can provide a basis for breeding and lay the foundation for gene cloning. Cucumber inbred lines NCG-122 with numerous spines and NCG-121 with few spines were used for genetic analysis and gene mapping in this study. Genetic analysis showed that the numerous spines trait in NCG-122 was qualitative, and a single recessive nuclear gene (ns) controlled this trait. The few spines trait was dominant over the numerous spines trait. In the preliminary genetic mapping of the ns gene, 8 SSR markers were found to be linked to ns, which mapped to chromosome 2 (Chr.2) of cucumber. The closest flanking markers SSR22338 and SSR11596 were linked to the ns gene, with genetic distances of 10.2 and 1.7cM, respectively. One-hundred and thirty pairs of new SSR primers and 28 pairs of Indel primers were developed based on sequence information in the preliminary mapping region of ns Fifteen SSR markers and 2 Indel markers were identified to be linked to the ns gene after analysis on the F2 mapping population using the new molecular markers. The 2 closest flanking markers, SSRns-127 and SSR04219, were 0.7 and 2.4 cM from ns, respectively. The physical distance between SSRns-127 and SSR04219 was 266.1kb, containing 27 predicted genes. Csa2G285390 was speculated as the probable candidate gene for numerous spines. The accuracy of the closest linked marker to the ns gene, SSRns-127, for MAS breeding was 95.0%. PMID:27317924
Analysis of Coincident HICO and Airborne Hyperspectral Images Over Lake Erie Western Basin HABs
NASA Astrophysics Data System (ADS)
Cline, M., Jr.; Becker, R.; Lekki, J.; Bridgeman, T. B.; Tokars, R. P.; Anderson, R. C.
2015-12-01
Harmful algal blooms (HABs) produce waterborne toxins that pose a significant threat to people, livestock, and wildlife. 40 million people in both Canada and the U.S. depend on Great Lakes water. In the summer of 2014, in the Lake Erie Western Basin, an HAB of the cyanobacteria Microsystis was so severe that a water-use ban was in effect for the greater Toledo area, Ohio. This shut off the water supply to over 400,000 people from a single water intake. We investigated bloom intensity, composition, and spatial variability by comparing hyperspectral data from NASA's HICO, multispectral data from MODIS spaceborne imagers and NASA GRC's HSI imagers to on-lake ASD radiometer measurements using in situ water quality testing as ground reference data, all acquired on a single day during the bloom in 2014. HICO imagery acquired on Aug 15, 2014 was spatially georeferenced and atmospherically corrected using empirical line method utilizing on-lake ASD spectra. HSI imagery were processed in a similar way. Cyanobacteria Index (CI) images were created from processed images using the Wynne (2010) algorithm, previously used for MODIS and MERIS imagery. This algorithm-generated CI images provide reliable results for both ground level (R²=0.7784), and satellite imagery (R²=0.7794) for seven sampling points in Lake Erie's western basin. Spatial variability in the bloom was high, and was not completely characterized by the lower spatial resolution MODIS data. The ability to robustly atmospherically correct and generate useful CI maps from airborne and satellite sensors can provide a time- and cost-effective method for HABs analysis. Timely processing of these high spatial and spectral resolution remote sensing data can aid in management of water intake resources.
NASA Astrophysics Data System (ADS)
Safavi, Hamid R.; Golmohammadi, Mohammad H.; Sandoval-Solis, Samuel
2016-08-01
The goal of this study is to develop and analyze three scenarios in the Zayandehrud river basin in Iran using a model already built and calibrated by Safavi et al. (2015) that has results for the baseline scenario. Results from the baseline scenario show that water demands will be supplied at the cost of depletion of surface and ground water resources, making this scenario undesirable and unsustainable. Supply Management, Demand Management, and Meta (supply and demand management) scenarios are the selected scenarios in this study. They are to be developed and declared into the Zayandehrud model to assess and evaluate the imminent status of the basin. Certain strategies will be employed for this purpose to improve and rectify the current management policies. The five performance criteria of time-based and volumetric reliability, resilience, vulnerability, and maximum deficit will be employed in the process of scenario analysis and evaluation. The results obtained from the performance criteria will be summed up into a so-called 'Water Resources Sustainability Index' to facilitate comparison among the likely trade-offs. Uncertainties arising from historical data, management policies, rainfall-runoff model, demand priorities, and performance criteria are considered in the proposed conceptual framework and modeled by appropriate approaches. Results show that the Supply Management scenario can be used to improve upon the demand supply but that it has no tangible effects on the improvement of the resources in the study region. In this regard, the Demand Management scenario is found to be more effective than the water supply one although it still remains unacceptable. Results of the Meta scenario indicate that both the supply and demand management scenarios must be applied if the water resources are to be safeguarded against degradation and depletion. In other words, the supply management scenario is necessary but not adequate; rather, it must be coupled to the demand
A Basin-based Analysis of Global Lake Stress from Scarcity of Sustainable Water Resource
NASA Astrophysics Data System (ADS)
Wang, J.; Sheng, Y.
2010-12-01
Lakes are a major storage of surface fresh water readily accessible to human. However, lake water resource is unequally distributed on Earth due to variations of lake abundance, human water demand, and availability of sustainable water supply (primarily, river discharge). This study aims at presenting a global view of contemporary lake stress through analyzing water availability and human demand at fine spatial resolutions. Two scientific questions are progressively explored: i) What is the geographic cross-tabulation of lake distribution vs. population and human water demand? and ii) What is the potential stress of lake water from the scarcity of river discharge? We begin with a straightforward analysis of the spatiotemporal pattern between lake and population distributions. Preliminary results indicate that excluding the extreme climatic zones such as the Pan-Arctic and Tibetan Plateau, lake densities exhibits an intrinsically positive correlation with population density and increase rate. Lake stresses on drainage basin levels are further quantified with integration of river discharge, lake volume, and water withdrawal data. Lake water per capita is computed for each basin. An index of lake water stress (LWS) is developed to characterize the pressure of unit lake/reservoir water exerted from the scarcity of river discharge due to water withdrawal. The revealed LWS pattern provides a spatial-explicit guideline with respect to how lake water is presently in stress and thus potentially redistributed under the baseline of sustainable water scarcity. Several major regions with high LWS values are highlighted to further compare the contributions of human demand and natural water availability to the local lake stress.
Analysis of sediment production from two small semiarid basins in Wyoming
Rankl, J.G.
1987-01-01
Data were collected at two small, semiarid basins in Wyoming to determine the relation between rainfall, runoff, and sediment production. The basins were Dugout Creek tributary and Saint Marys Ditch tributary. Sufficient rainfall and runoff data were collected at Dugout Creek tributary to determine the source of sediment and the dominant sediment production processes. Because runoff from only one storm occurred in Saint Marys Ditch tributary, emphasis of the study was placed on the analysis of data collected at Dugout Creek tributary. At Dugout Creek tributary, detailed measurements were made to establish the source of sediment. To determine the quantity of material removed from headcuts during the study, two headcuts were surveyed. Aerial photographs were used to define movement of all headcuts. The total quantity of sediment removed from all headcuts between September 26, 1982, and September 26, 1983, was estimated to be 1,220 tons, or 15%-25% of the estimated total sediment load passing the streamflow-gaging station. A soil plot was used to sample upland erosion. A rainfall and runoff modeling system was used to evaluate the interaction between the physical processes which control sediment production. The greatest change in computed sediment load was caused by changing the parameter values for equations used to compute the detachment of sediment particles by rainfall and overland flow resulted in very small changes in computed sediment load. The upland areas were the primary source of sediment. A relationship was developed between the peak of storm runoff and the total sediment load for that storm runoff. The sediment concentration used to compute the total sediment load for the storm runoff was determined from sediment samples collected by two automatic pumping samplers. The coefficient of variation of the relationship is 34% with a 0.99 correlation coefficient. (Author 's abstract)
NASA Astrophysics Data System (ADS)
Chen, Liang-Yu; Pan, Min-Cheng; Pan, Min-Chun
2013-01-01
The purpose of this study is to propose an objective contrast-and-size detail (CSD) analysis for near infrared diffuse optical tomography (NIR DOT), of which the concept is derived from the subjective contrast detail (CD) analysis. We define a measure for numerical CSD analysis based on the resolution estimation of contrast and size. Following that, the contrast-and-size map of resolution can be calculated and displayed for each corresponding image in the map; furthermore, a CSD resolution curve can be plotted by calculating the average value of the projection corresponding to the physical quantity/axis (size or contrast). To provide some worked examples about the proposed CSD analysis evaluating the imaging performance of different reconstruction methods, Tikhonov regularization and edge-preserving regularization with different weighting functions were employed. Results suggested that using edge-preserving regularization with the generalized Lorentzian weighting function is the most attractive for the estimation of absorption-coefficient images.
Stress analysis and damage evaluation of flawed composite laminates by hybrid-numerical methods
NASA Technical Reports Server (NTRS)
Yang, Yii-Ching
1992-01-01
Structural components in flight vehicles is often inherited flaws, such as microcracks, voids, holes, and delamination. These defects will degrade structures the same as that due to damages in service, such as impact, corrosion, and erosion. It is very important to know how a structural component can be useful and survive after these flaws and damages. To understand the behavior and limitation of these structural components researchers usually do experimental tests or theoretical analyses on structures with simulated flaws. However, neither approach has been completely successful. As Durelli states that 'Seldom does one method give a complete solution, with the most efficiency'. Examples of this principle is seen in photomechanics which additional strain-gage testing can only average stresses at locations of high concentration. On the other hand, theoretical analyses including numerical analyses are implemented with simplified assumptions which may not reflect actual boundary conditions. Hybrid-Numerical methods which combine photomechanics and numerical analysis have been used to correct this inefficiency since 1950's. But its application is limited until 1970's when modern computer codes became available. In recent years, researchers have enhanced the data obtained from photoelasticity, laser speckle, holography and moire' interferometry for input of finite element analysis on metals. Nevertheless, there is only few of literature being done on composite laminates. Therefore, this research is dedicated to this highly anisotropic material.
Numerical studies of motion of vortex filaments - Implementing the asymptotic analysis
NASA Technical Reports Server (NTRS)
Liu, C. H.; Tavantzis, J.; Ting, L.
1984-01-01
A computational code is developed for the integro-differential equations governing the motion of the centerlines of vortex filaments submerged in a background potential flow. These equations, which are derived from the method of matched asymptotic analysis, include the effect of the decaying large-magnitude circumferential and axial velocity components in the vortical cores. Numerical examples are presented to assess the effect of a large axial velocity and that of nonsimilar initial profiles in the vortical cores. The initial configurations of the filaments are chosen so as to fulfill the basic assumption of the asymptotic analysis, which is that the effective vortical core size is much smaller than all the other length scales in the flowfield, e.g., the radius of curvature and the interfilament distance. The computations are continued until the basic assumption is no longer valid, that is when the merging or intersection of filaments has begun. A classification of the various types of local or global merging or intersection of filaments is made and demonstrated by numerical examples. It is then shown that the asymptotic solution not only provides the initial data but also can be used to formulate the appropriate boundary conditions for the numerical solution of a merged region.
Experimental and numerical analysis of metal leaching from fly ash-amended highway bases
Cetin, Bora; Aydilek, Ahmet H.; Li, Lin
2012-05-15
Highlights: Black-Right-Pointing-Pointer This study is the evaluation of leaching potential of fly ash-lime mixed soils. Black-Right-Pointing-Pointer This objective is met with experimental and numerical analysis. Black-Right-Pointing-Pointer Zn leaching decreases with increase in fly ash content while Ba, B, Cu increases. Black-Right-Pointing-Pointer Decrease in lime content promoted leaching of Ba, B and Cu while Zn increases. Black-Right-Pointing-Pointer Numerical analysis predicted lower field metal concentrations. - Abstract: A study was conducted to evaluate the leaching potential of unpaved road materials (URM) mixed with lime activated high carbon fly ashes and to evaluate groundwater impacts of barium, boron, copper, and zinc leaching. This objective was met by a combination of batch water leach tests, column leach tests, and computer modeling. The laboratory tests were conducted on soil alone, fly ash alone, and URM-fly ash-lime kiln dust mixtures. The results indicated that an increase in fly ash and lime content has significant effects on leaching behavior of heavy metals from URM-fly ash mixture. An increase in fly ash content and a decrease in lime content promoted leaching of Ba, B and Cu whereas Zn leaching was primarily affected by the fly ash content. Numerically predicted field metal concentrations were significantly lower than the peak metal concentrations obtained in laboratory column leach tests, and field concentrations decreased with time and distance due to dispersion in soil vadose zone.
Basins of attraction for chimera states
NASA Astrophysics Data System (ADS)
Martens, Erik A.; Panaggio, Mark J.; Abrams, Daniel M.
2016-02-01
Chimera states—curious symmetry-broken states in systems of identical coupled oscillators—typically occur only for certain initial conditions. Here we analyze their basins of attraction in a simple system comprised of two populations. Using perturbative analysis and numerical simulation we evaluate asymptotic states and associated destination maps, and demonstrate that basins form a complex twisting structure in phase space. Understanding the basins’ precise nature may help in the development of control methods to switch between chimera patterns, with possible technological and neural system applications.
NASA Astrophysics Data System (ADS)
Atha, J. B.
2010-12-01
The production and entrainment of large wood and its dynamics within fluvial channels in riparian areas increases complexity of river environments by providing aquatic habitat in addition to having a significant role in modifying channel hydraulics and morphology. While the presence and dynamics of large wood in river floodplains have been studied in a multitude of settings due to its importance in monitoring and managing ecohydrologic systems; limitations occur when studying fluvial wood on a basin scale. With the employment of Google Earth, satellite images may be used to identify large wood and measure floodplain width across broader spatial scales previously inhibited by cumbersome remote sensing and mapped data. In this study relationships between the amount of fluvial wood present on a reach-scale as well as a basin scale and the geomorphology of the main-stem of the Queets River in the Olympic Peninsula, Washington are examined. Analysis of the data reveals significance in several of the variables collected through Google Earth in addition to drainage area derivation through GIS.
NASA Astrophysics Data System (ADS)
Baker, J.; Lowe, C.
2005-12-01
The Bowser and Sustut basins occupy an area of more than 60,000 km2 in northern British Columbia, Canada. They comprise three, dominantly sedimentary, stratigraphic successions, in part overlapping in age: the Bowser Lake Group, the Skeena Group, and the Sustut Group. These three successions overlie arc volcanic and volcaniclastic strata of Stikinia, an allochtonous island arc terrane that accreted to the western margin of North America in the Early Jurassic to early Middle Jurassic. All three basin successions and underlying Stikinia were deformed during development of a thin-skinned fold and thrust belt (the Skeena Fold and Thrust Belt) in Cretaceous and possibly into earliest Tertiary time. Recently, the basins have been the focus of intense geological studies which have resulted in major revisions to the stratigraphic and structural framework of the basins and demonstrated that they have significantly higher petroleum potential than had been previously recognized. To advance these new findings further requires better imaging of the three-dimensional geometry and architecture of the basins. In this study we harness existing magnetic anomaly data to provide the first quantitative estimates of sedimentary thickness across the entire extents of both basins. Our results, which are in general in accord with geological interpretations, indicate that basin-fill is relatively thin and fairly uniform in the Sustut Basin (2.5-3 km), but highly variable in the Bowser Basin, ranging from less than 2 km to more than 6 km. Overall, sedimentary fill is thicker in the northern half of Bowser Basin compared to the south and is typically less than 2 km near the basins northern, western and southern margins. In addition, we demonstrate how a large, buried intrusion beneath the northeast part of Bowser Basin can account for an observed magnetic anomaly and explain the high coalification gradients and localized high maturation levels of the overlying sedimentary rocks. Neither of
Residence times in river basins as determined by analysis of long-term tritium records
NASA Astrophysics Data System (ADS)
Michel, Robert L.
1992-01-01
The US Geological Survey has maintained a network of stations to collect samples for the measurement of tritium concentrations in precipitation and streamflow since the early 1960s. Tritium data from outflow waters of river basins draining 4500-75000 km 2 are used to determine average residence times of water within the basins. The basins studied are the Colorado River above Cisco, Utah; the Kissimmee River above Lake Okeechobee, Florida; the Mississippi River above Anoka, Minnesota; the Neuse River above Streets Ferry Bridge near Vanceboro, North Carolina; the Potomac River above Point of Rocks, Maryland; the Sacramento River above Sacramento, California; the Susquehanna River above Harrisburg, Pennsylvania. The basins are modeled with the assumption that the outflow in the river comes from two sources—prompt (within-year) runoff from precipitation, and flow from the long-term reservoirs of the basin. Tritium concentration in the outflow water of the basin is dependent on three factors: (1) tritium concentration in runoff from the long-term reservoir, which depends on the residence time for the reservoir and historical tritium concentrations in precipitation; (2) tritium concentrations in precipitation (the within-year runoff component); (3) relative contributions of flow from the long-term and within-year components. Predicted tritium concentrations for the outflow water in the river basins were calculated for different residence times and for different relative contributions from the two reservoirs. A box model was used to calculate tritium concentrations in the long-term reservoir. Calculated values of outflow tritium concentrations for the basin were regressed against the measured data to obtain a slope as close as possible to 1. These regressions assumed an intercept of zero and were carried out for different values of residence time and reservoir contribution to maximize the fit of modeled versus actual data for all the above rivers. The final slopes of
Residence times in river basins as determined by analysis of long-term tritium records
Michel, R.L.
1992-01-01
The US Geological Survey has maintained a network of stations to collect samples for the measurement of tritium concentrations in precipitation and streamflow since the early 1960s. Tritium data from outflow waters of river basins draining 4500-75000 km2 are used to determine average residence times of water within the basins. The basins studied are the Colorado River above Cisco, Utah; the Kissimmee River above Lake Okeechobee, Florida; the Mississippi River above Anoka, Minnesota; the Neuse River above Streets Ferry Bridge near Vanceboro, North Carolina; the Potomac River above Point of Rocks, Maryland; the Sacramento River above Sacramento, California; the Susquehanna River above Harrisburg, Pennsylvania. The basins are modeled with the assumption that the outflow in the river comes from two sources-prompt (within-year) runoff from precipitation, and flow from the long-term reservoirs of the basin. Tritium concentration in the outflow water of the basin is dependent on three factors: (1) tritium concentration in runoff from the long-term reservoir, which depends on the residence time for the reservoir and historical tritium concentrations in precipitation; (2) tritium concentrations in precipitation (the within-year runoff component); (3) relative contributions of flow from the long-term and within-year components. Predicted tritium concentrations for the outflow water in the river basins were calculated for different residence times and for different relative contributions from the two reservoirs. A box model was used to calculate tritium concentrations in the long-term reservoir. Calculated values of outflow tritium concentrations for the basin were regressed against the measured data to obtain a slope as close as possible to 1. These regressions assumed an intercept of zero and were carried out for different values of residence time and reservoir contribution to maximize the fit of modeled versus actual data for all the above rivers. The final slopes of the
Analysis of the flamelet concept in the numerical simulation of laminar partially premixed flames
Consul, R.; Oliva, A.; Perez-Segarra, C.D.; Carbonell, D.; de Goey, L.P.H.
2008-04-15
The aim of this work is to analyze the application of flamelet models based on the mixture fraction variable and its dissipation rate to the numerical simulation of partially premixed flames. Although the main application of these models is the computation of turbulent flames, this work focuses on the performance of flamelet concept in laminar flame simulations removing, in this way, turbulence closure interactions. A well-known coflow methane/air laminar flame is selected. Five levels of premixing are taken into account from an equivalence ratio {phi}={infinity} (nonpremixed) to {phi}=2.464. Results obtained using the flamelet approaches are compared to data obtained from the detailed solution of the complete transport equations using primitive variables. Numerical simulations of a counterflow flame are also presented to support the discussion of the results. Special emphasis is given to the analysis of the scalar dissipation rate modeling. (author)
RC structures strengthened by metal shear panels: experimental and numerical analysis
De Matteis, G.; Formisano, A.; Mazzolani, F. M.
2008-07-08
Metal shear panels (MSPs) may be effectively used as a lateral load resisting system for framed structures. In the present paper, such a technique is applied for the seismic protection of existing RC buildings, by setting up a specific design procedure, which has been developed on the basis of preliminary full-scale experimental tests. The obtained results allowed the development of both simplified and advanced numerical models of both the upgraded structure and the applied shear panels. Also, the proposed design methodology, which is framed in the performance base design philosophy, has been implemented for the structural upgrading of a real Greek existing multi-storey RC building. The results of the numerical analysis confirmed the effectiveness of the proposed technique, also emphasising the efficiency of the implemented design methodology.
Numerical Analysis of Incipient Separation on 53 Deg Swept Diamond Wing
NASA Technical Reports Server (NTRS)
Frink, Neal T.
2015-01-01
A systematic analysis of incipient separation and subsequent vortex formation from moderately swept blunt leading edges is presented for a 53 deg swept diamond wing. This work contributes to a collective body of knowledge generated within the NATO/STO AVT-183 Task Group titled 'Reliable Prediction of Separated Flow Onset and Progression for Air and Sea Vehicles'. The objective is to extract insights from the experimentally measured and numerically computed flow fields that might enable turbulence experts to further improve their models for predicting swept blunt leading-edge flow separation. Details of vortex formation are inferred from numerical solutions after establishing a good correlation of the global flow field and surface pressure distributions between wind tunnel measurements and computed flow solutions. From this, significant and sometimes surprising insights into the nature of incipient separation and part-span vortex formation are derived from the wealth of information available in the computational solutions.
Numerical analysis of the beam quality and spectrum of wavelength-beam-combined laser diode arrays
NASA Astrophysics Data System (ADS)
Tang, Xuan; Wang, Xiao-Jun; Ke, Wei-Wei
2015-02-01
In this paper, a numerical model is presented to simulation the performance of the wavelength-beam-combined laser diode arrays (LDA) system. The eigen mode expansion method is used to describe the two-dimensional optical amplification and the strength of field feedback of external cavity. To describe the mode competition in laser diodes, the gain saturation effect is considered. The two-dimension distributions of the carrier concentration, recombination rates, and optical gain are calculated for solving the laser dynamic equation. The Fresnel integration, grating equation and mode overlap integration are used to obtain the feedback coefficient of extent cavity diffraction. Quantum noise is considered to evaluate the spectral linewidth of semiconductor laser. Based on the numerical model, the impact of the mutual optical feedback on the beam quality and spectrum of the LDA is present and analysis.
Numerical analysis of composite systems by using interphase/interface models
NASA Astrophysics Data System (ADS)
Chaboche, J. L.; Girard, R.; Schaff, A.
1997-07-01
The paper considers two classes of approaches for the numerical analysis of composite systems: the first one discretizes the assumed interphase (between matrix and fibre) as volumic elements and uses material models that degenerate from Continuum Damage Mechanics. The second one introduces interface elements that relate non linearly the normal and tangential tractions to the corresponding displacement discontinuities, incorporating a progressive decohesion, following the lines of Needleman (1987) and Tvergaard (1990). The respective capabilities of these two approaches are discussed on the basis of some numerical results obtained for a unidirectional metal matrix composite system. When the models are consistently adjusted they are able to reproduce the same kind of results. The advantages of the second class of method is underlined and two new versions of interface models are proposed that guarantee the continuity and the monotonicity of the shear stiffness between the progressive decohesion phase and the subsequent contact/friction law that plays role under compressive shear after complete separation.
Samak, M. Mosleh E. Abu; Bakar, A. Ashrif A.; Kashif, Muhammad; Zan, Mohd Saiful Dzulkifly
2016-01-01
This paper discusses numerical analysis methods for different geometrical features that have limited interval values for typically used sensor wavelengths. Compared with existing Finite Difference Time Domain (FDTD) methods, the alternating direction implicit (ADI)-FDTD method reduces the number of sub-steps by a factor of two to three, which represents a 33% time savings in each single run. The local one-dimensional (LOD)-FDTD method has similar numerical equation properties, which should be calculated as in the previous method. Generally, a small number of arithmetic processes, which result in a shorter simulation time, are desired. The alternating direction implicit technique can be considered a significant step forward for improving the efficiency of unconditionally stable FDTD schemes. This comparative study shows that the local one-dimensional method had minimum relative error ranges of less than 40% for analytical frequencies above 42.85 GHz, and the same accuracy was generated by both methods.
Borazjani, Iman; Westerdale, John; McMahon, Eileen M.; Rajaraman, Prathish K.; Heys, Jeffrey J.
2013-01-01
The left ventricle (LV) pumps oxygenated blood from the lungs to the rest of the body through systemic circulation. The efficiency of such a pumping function is dependent on blood flow within the LV chamber. It is therefore crucial to accurately characterize LV hemodynamics. Improved understanding of LV hemodynamics is expected to provide important clinical diagnostic and prognostic information. We review the recent advances in numerical and experimental methods for characterizing LV flows and focus on analysis of intraventricular flow fields by echocardiographic particle image velocimetry (echo-PIV), due to its potential for broad and practical utility. Future research directions to advance patient-specific LV simulations include development of methods capable of resolving heart valves, higher temporal resolution, automated generation of three-dimensional (3D) geometry, and incorporating actual flow measurements into the numerical solution of the 3D cardiovascular fluid dynamics. PMID:23690874
Numerical analysis of the method of internal dialysis of giant axons.
Horn, L W
1983-01-01
This paper presents a numerical analysis of the method of internal dialysis used for studies of membrane transport in giant axons. Account is taken of the complete geometry, end effects, and finite dialyzate flow rates. Both influx and efflux experimental conditions are considered. Results place quantitative limits on system performance that are sufficiently general for use in experimental design. The completeness of solute equilibration and the uniformity of solute concentration at the axon membrane are assessed, as well as the sensitivity to dialysis solution flow rate. The effects of undialyzed axon ends on the equilibration rate and on the uniformity of concentration are determined, and the contribution of undialyzed ends to influx measurements is evaluated. Equilibration times are correlated with physical properties of axoplasm and dialysis tubing, and with dialysis solution flow rate. Numerical results confirm the general qualitative assessments of the method that are based on years of successful application. PMID:6191787
NASA Astrophysics Data System (ADS)
van Alstine, Jana M.
The Ordos basin is a large, non-marine sedimentary basin presently located in north-central China. During the Paleozoic and Mesozoic, the basin was located at the center of Asian continental assembly, and was a focused zone of deformation. Throughout its evolution, stress has been accommodated by deformation on the Ordos basin margins, while the interior has remained stable. Deformation of the margins generated narrow perimeter basins along the Triassic northwest and Jurassic northeast margins. The south and southwestern Ordos basin was a large subsiding Triassic-Jurassic foreland connected to a flat-laying Ordos basin interior, which remains undeformed with approximately 4 km of sedimentary fill. In this study, detailed fluvial and lacustrine stratigraphy was used to create depositional frameworks for the perimeter sub-basins. Each was analyzed using the frameworks, available structural constraints and paleoclimate data. Previous studies of the northern Ordos sub-basins interpreted the basins as extensional half-grabens, which do not agree with their tectonic context. In this study, the data and interpretations of the sub-basins refine the previous interpretations, and (1) offer alternative scenarios of sub-basin development, (2) integrate the development scenarios of the sub-basins into the history of the larger Ordos basin, and (3) suggest a transtensional boundary along the northern Ordos basin. On the south and west margins and the Ordos basin interior, observations and interpretations made in this study were used in conjunction with available published data. This study shows that a large lake formed in a foreland depression along the south and southwestern margins. It expanded to the northeast from the Late Triassic through the Middle Jurassic to occupy the southern half of the Ordos basin. The detailed analyses of the basin margins and interior are used to develop a comprehensive understanding of the tectono-sedimentary evolution of an integrated Ordos Basin
Regional analysis of changes in snow pack in mountainous basins in the central Danube region
NASA Astrophysics Data System (ADS)
Balint, Gabor; Juričeková, Katarina; Gauzer, Balazs; Hlavčová, Kamila; Kohnová, Silvia; Szolgay, Jan; Zsideková, Beata
2013-04-01
Accurate estimation of the volume of water stored in the snow pack and its rate of release is essential to predict the flow during the snowmelt period. In mountainous drainage basins water stored in the snow pack represents an important component of the water budget. Two modelling tools are compared. The first, HOLV snowmelt model is developed by the Hungarian National Hydrological Forecasting Service (VITUKI NHFS) for regional assessment of snow accumulation and ablation of the central Danube. The model originates from the early 80's and it is under continuous development, while its recent distributed version over a grid with 0.1 degree resolution is in use. The snowmelt model has a flexible structure; it is able to change its own structure in function of data availability. In case when only precipitation and air temperature data are available temperature index method is used. When also other data are accessible (cloudiness, dew point, wind speed) using of energy balance model is to be preferred. If there are suitable data available for calculation of the energy terms, the energy balance method can be applied. The second semi-distributed Hron model, developed at the Slovak University of Technology was applied to a smaller sub-basin to represent spatial distribution of snow cover by simulated snow water equivalent. The upper Hron river basin with an area of 1766 km2 is located in central Slovakia. The conceptual semi-distributed tool applied contains three basic storage components with 15 calibrated parameters, as the flow routing component the cascade of linear reservoirs is used as opposed to the original simple triangular routing function. The snow sub-model uses the temperature index (degree-day) method for snow accumulation and snowmelt calculations. Uncertainty of model parameters was reduced by multi-calibration on the mean daily discharges in the basin outlet and measured stations data of snow water equivalent. Changes in the model parameters during the
The role of scenario analysis in water resources management in Yanqi Basin, Xinjiang, China
NASA Astrophysics Data System (ADS)
Li, N.; Kinzelbach, W. K.; Li, W.; Dong, X.
2011-12-01
With the rapid increase of world population and food demand, the demand for water resources is also increasing. At the same time shifts in rain patterns due to global climate change make the water resources situation more uncertain. A global water crisis can therefore not be excluded. The socio-economic and environmental problems induced by such a water crisis are especially prominent in arid and semiarid regions. The Yanqi Basin in Xinjiang province is a typical case study in China's arid and semi-arid areas, where rainfall is scarce and evaporation is extremely high. Thus its water resources have been under great pressure to satisfy the increasing water demand of agriculture and urban and industrial expansion in the last decades. The development has been accompanied by a number of environmental problems. Yanqi Basin is an important cultivated area which is irrigated by water diverted from rivers. Because of the long-term flood irrigation and an inefficient drainage system, the groundwater level under the cultivated area rose, accelerating the phreatic evaporation and leading to increased soil salinization. Simultaneously, the water quantity and quality of Boston Lake have been impaired in past years because of the decreased river discharge and the increased salt flux contained in the drainage discharge. Thus the ecosystems depending on the inflow to and outflow from the lake suffered. The riverine forests in the downstream area were degraded due to declining groundwater levels, and aquatic life as well as downstream water users had to cope with deteriorating water quality. The big challenge for decision makers in the basin is how to balance the justified requirements of agriculture, industrial development and the ecosystem. In order to provide a scientific basis to the decision making process, a scenario analysis was adopted. Here several scenarios are proposed: the basic scenario, scenario 1, describes the status of the year 2008. A second scenario maximizes the
NASA Astrophysics Data System (ADS)
Gomez-Cabrera, Pedro Tomas
2003-10-01
Southeastern Mexico has been affected by regional and local tectonic events. Regional tectonic events are the Gulf of Mexico opening and the lateral movement of micro-plates on the Pacific margin. The local tectonic events are related to salt tectonics. Autochthonous Jurassic salt serves as the detachment level for the main compressional event in the late Miocene. Jurassic salt was allochthonously emplaced in the late Miocene, then partially displaced by a huge quantity of terrigenous sediments during the Plio-Pleistocene. This research is a study of the main geological processes that have influenced the structural and stratigraphic evolution of the Neogene sediments in the offshore portion of the Salina del Istmo basin known as the Marbella area. Owing to data availability, the project was divided into regional and local studies. The regional study is based on 2D multi-channel seismic reflection data, and the local study is based on a 3D seismic streamer survey. Structural analysis in the regional study permits the recognition of four buried fold belts (Agua Dulce, Catemaco, Marbella, and Marbella Norte) trending roughly NE. These fold belts are the result of tectonic convergence in the pacific margin during late Miocene. The Agua Dulce and Marbella Norte fold belts are separated by an enormous salt withdrawal basin called the Pescadores basin. The Pescadores basin is bounded on the north by a spectacular stepped, counter-regional structure. Beyond the Pescadores basin, a salt mini-basin area is recognized in the upper continental slope. Another important structural element is the Sal Somera canopy in the southern part of the study area. Sedimentation-rate analysis, based on isochore mapping in the local study area, indicates that from SB-2.4 to SB-2.6 Ma, deposition rate peaked with a maximum of 7.5 mm/yr. Regional and local structural restorations show that, in general, the maximum allochthonous salt mobilization was during the Plio-Pleistocene because of the
Brown, C. Erwin
1987-01-01
Sixty-two Schlumberger electrical soundings were made in the Durham Triassic basin in an effort to determine basin structural geometry, depth of the sedimentary layers, and spatial distribution of individual rock facies. A digital computer program was used to invert the sounding curves of apparent resistivity versus distance to apparent resistivity versus depth. The apparent-resistivity-versus-depth data from the computer-modeling program were used to construct a geoelectric model of the basin that is believed to accurately represent the subsurface geology of the basin. The largest depth to basement in the basin along a resistivity profile (geoelectric section) was determined to be 1,800 m. A resistivity decrease was observed on certain soundings from depths of 100 to 1,000 m; below a 1,000-m depth, apparent resistivity increased to the bottom of the basin. Resistivity values for basement rocks were greater than 1,000 ohm-m and less than 350 ohm-m for the sedimentary layers in the basin. The data suggest that the basin contains a system of step faults near its eastern boundary. ?? 1987.
Drought Analysis of the Haihe River Basin Based on GRACE Terrestrial Water Storage
Wang, Jianhua; Jiang, Dong; Huang, Yaohuan; Wang, Hao
2014-01-01
The Haihe river basin (HRB) in the North China has been experiencing prolonged, severe droughts in recent years that are accompanied by precipitation deficits and vegetation wilting. This paper analyzed the water deficits related to spatiotemporal variability of three variables of the gravity recovery and climate experiment (GRACE) derived terrestrial water storage (TWS) data, precipitation, and EVI in the HRB from January 2003 to January 2013. The corresponding drought indices of TWS anomaly index (TWSI), precipitation anomaly index (PAI), and vegetation anomaly index (AVI) were also compared for drought analysis. Our observations showed that the GRACE-TWS was more suitable for detecting prolonged and severe droughts in the HRB because it can represent loss of deep soil water and ground water. The multiyear droughts, of which the HRB has sustained for more than 5 years, began in mid-2007. Extreme drought events were detected in four periods at the end of 2007, the end of 2009, the end of 2010, and in the middle of 2012. Spatial analysis of drought risk from the end of 2011 to the beginning of 2012 showed that human activities played an important role in the extent of drought hazards in the HRB. PMID:25202732
Analysis of the Water Resources on Baseflow River Basin in Jeju Island, Korea
NASA Astrophysics Data System (ADS)
Yang, S.-K.; Jung, W.-Y.; Kang, M.-S.
2012-04-01
Jeju Island is a volcanic island located at the southernmost of Korea, and is the heaviest raining area in Korea, but due to its hydrological / geological characteristics different from those of inland areas, most streams are of the dry form, and it relies on groundwater for water resources. As for some streams, however, springwater is discharged at a point near the downstream of the final discharge to maintain the flow of the stream; this has been developed as the source for water supply since the past, but the studies on detail observations and analysis are yet inadequate. This study utilizes the ADCP (Acoustic Doppler Current Profiler) hydrometer to regularly observe the flow amount of base run-off stream, and the water resources of base discharge basin of Jeju Island were analyzed using the SWAT (Soil & Water Assessment Tool) model. The detail water resource analysis study using modeling and site observation with high precision for Jeju Island water resources is expected to become the foundation for efficient usage and security of water resources against future climate changes.
Towards an integrated analysis of rural systems: the case study of the Alento basin
NASA Astrophysics Data System (ADS)
Quaranta, Giovanni; Salvia, Rosanna
2014-05-01
The role and the functions of rural areas are undergoing considerable change due to economic, social and environmental drivers. The outcome of the transformation is the production of highly heterogeneous landscapes, rural mosaics, which are home to varying degrees of intensity of land-use and processes of deactivation, abandonment and land degradation. The identification of rural mosaics has implications both for determining the impacts on the stock of connected natural resources and for defining measures and policies able to support the resilience of rural territories and the identification of sustainable strategies for development. The study proposes a methodology for the integrated analysis of the rural territory which combines the analysis of land cover dynamics, using GIS, with an assessment of socio-economic dynamics, reconstructed through the combined use of indicators and local history, and which is aware that the differences and peculiarities within rural territories are the result of actions taken over time and of the different adaptive strategies undertaken by communities operating in different fields, under the influence of specific ecologic and environmental conditions. The methodology, applied to a socio-ecological system which is representative of the Mediterranean basin, is proposed as a tool to support the territorialisation of polices, opening the process up to perspectives able to better comprehend the dynamic evolution of rural territories, internalising that evolution in the definition of the instruments and measures to adopt.
Stream network analysis from orbital and suborbital imagery, Colorado River Basin, Texas
NASA Technical Reports Server (NTRS)
Baker, V. R. (Principal Investigator)
1973-01-01
The author has identified the following significant results. Orbital SL-2 imagery (earth terrain camera S-190B), received September 5, 1973, was subjected to quantitative network analysis and compared to 7.5 minute topographic mapping (scale: 1/24,000) and U.S.D.A. conventional black and white aerial photography (scale: 1/22,200). Results can only be considered suggestive because detail on the SL-2 imagery was badly obscured by heavy cloud cover. The upper Bee Creek basin was chosen for analysis because it appeared in a relatively cloud-free portion of the orbital imagery. Drainage maps were drawn from the three sources digitized into a computer-compatible format, and analyzed by the WATER system computer program. Even at its small scale (1/172,000) and with bad haze the orbital photo showed much drainage detail. The contour-like character of the Glen Rose Formation's resistant limestone units allowed channel definition. The errors in pattern recognition can be attributed to local areas of dense vegetation and to other areas of very high albedo caused by surficial exposure of caliche. The latter effect caused particular difficulty in the determination of drainage divides.
Drought analysis of the Haihe river basin based on GRACE terrestrial water storage.
Wang, Jianhua; Jiang, Dong; Huang, Yaohuan; Wang, Hao
2014-01-01
The Haihe river basin (HRB) in the North China has been experiencing prolonged, severe droughts in recent years that are accompanied by precipitation deficits and vegetation wilting. This paper analyzed the water deficits related to spatiotemporal variability of three variables of the gravity recovery and climate experiment (GRACE) derived terrestrial water storage (TWS) data, precipitation, and EVI in the HRB from January 2003 to January 2013. The corresponding drought indices of TWS anomaly index (TWSI), precipitation anomaly index (PAI), and vegetation anomaly index (AVI) were also compared for drought analysis. Our observations showed that the GRACE-TWS was more suitable for detecting prolonged and severe droughts in the HRB because it can represent loss of deep soil water and ground water. The multiyear droughts, of which the HRB has sustained for more than 5 years, began in mid-2007. Extreme drought events were detected in four periods at the end of 2007, the end of 2009, the end of 2010, and in the middle of 2012. Spatial analysis of drought risk from the end of 2011 to the beginning of 2012 showed that human activities played an important role in the extent of drought hazards in the HRB. PMID:25202732
Woolfenden, Linda R.; Koczot, Kathryn M.
2001-01-01
The Rialto?Colton Basin, in western San Bernardino County, California, was chosen for storage of imported water because of the good quality of native ground water, the known storage capacity for additional ground-water storage in the basin, and the availability of imported water. To supplement native ground-water resources and offset overdraft conditions in the basin during dry periods, artificial-recharge operations during wet periods in the Rialto?Colton Basin were begun in 1982 to store surplus imported water. Local water purveyors recognized that determining the movement and ultimate disposition of the artificially recharged imported water would require a better understanding of the ground-water flow system. In this study, a finite-difference model was used to simulate ground-water flow in the Rialto?Colton Basin to gain a better understanding of the ground-water flow system and to evaluate the hydraulic effects of artificial recharge of imported water. The ground-water basin was simulated as four horizontal layers representing the river- channel deposits and the upper, middle, and lower water-bearing units. Several flow barriers bordering and internal to the Rialto?Colton Basin influence the direction of ground-water flow. Ground water may flow relatively unrestricted in the shallow parts of the flow system; however, the faults generally become more restrictive at depth. A particle-tracking model was used to simulate advective transport of imported water within the ground-water flow system and to evaluate three artificial-recharge alternatives. The ground-water flow model was calibrated to transient conditions for 1945?96. Initial conditions for the transient-state simulation were established by using 1945 recharge and discharge rates, and assuming no change in storage in the basin. Average hydrologic conditions for 1945?96 were used for the predictive simulations (1997?2027). Ground-water-level measurements made during 1945 were used for comparison with the
The Analysis and Design of Low Boom Configurations Using CFD and Numerical Optimization Techniques
NASA Technical Reports Server (NTRS)
Siclari, Michael J.
1999-01-01
The use of computational fluid dynamics (CFD) for the analysis of sonic booms generated by aircraft has been shown to increase the accuracy and reliability of predictions. CFD takes into account important three-dimensional and nonlinear effects that are generally neglected by modified linear theory (MLT) methods. Up to the present time, CFD methods have been primarily used for analysis or prediction. Some investigators have used CFD to impact the design of low boom configurations using trial and error methods. One investigator developed a hybrid design method using a combination of Modified Linear Theory (e.g. F-functions) and CFD to provide equivalent area due to lift driven by a numerical optimizer to redesign or modify an existing configuration to achieve a shaped sonic boom signature. A three-dimensional design methodology has not yet been developed that completely uses nonlinear methods or CFD. Constrained numerical optimization techniques have existed for some time. Many of these methods use gradients to search for the minimum of a specified objective function subject to a variety of design variable bounds, linear and nonlinear constraints. Gradient based design optimization methods require the determination of the objective function gradients with respect to each of the design variables. These optimization methods are efficient and work well if the gradients can be obtained analytically. If analytical gradients are not available, the objective gradients or derivatives with respect to the design variables must be obtained numerically. To obtain numerical gradients, say, for 10 design variables, might require anywhere from 10 to 20 objective function evaluations. Typically, 5-10 global iterations of the optimizer are required to minimize the objective function. In terms of using CFD as a design optimization tool, the numerical evaluation of gradients can require anywhere from 100 to 200 CFD computations per design for only 10 design variables. If one CFD
McTaggart, Lisa R; Brown, Elizabeth M; Richardson, Susan E
2016-01-01
Blastomyces dermatitidis and Blastomyces gilchristii are dimorphic fungal pathogens that cause serious pulmonary and systemic infections in humans. Although their natural habitat is in the environment, little is known about their specific ecologic niche(s). Here, we analyzed 25 microsatellite loci from 169 strains collected from various regions throughout their known endemic range in North America, representing the largest and most geographically diverse collection of isolates studied to date. Genetic analysis of multilocus microsatellite data divided the strains into four populations of B. dermatitidis and four populations of B. gilchristii. B. dermatitidis isolates were recovered from areas throughout North America, while the B. gilchristii strains were restricted to Canada and some northern US states. Furthermore, the populations of both species were associated with major freshwater drainage basins. The four B. dermatitidis populations were partitioned among (1) the Nelson River drainage basin, (2) the St. Lawrence River and northeast Atlantic Ocean Seaboard drainage basins, (3) the Mississippi River System drainage basin, and (4) the Gulf of Mexico Seaboard and southeast Atlantic Ocean Seaboard drainage basins. A similar partitioning of the B. gilchristii populations was observed among the more northerly drainage basins only. These associations suggest that the ecologic niche where the sexual reproduction, growth, and dispersal of B. dermatitidis and B. gilchristii occur is intimately linked to freshwater systems. For most populations, sexual reproduction was rare enough to produce significant linkage disequilibrium among loci but frequent enough that mating-type idiomorphic ratios were not skewed from 1:1. Furthermore, the evolutionary divergence of B. dermatitidis and B. gilchristii was estimated at 1.9 MYA during the Pleistocene epoch. We suggest that repeated glaciations during the Pleistocene period and resulting biotic refugia may have provided the
Wang, Weiliang; Liu, Xiaohui; Wang, Yufan; Guo, Xiaochun; Lu, Shaoyong
2016-03-01
Based on the data analysis of the water environmental quality and economic development from 2002 to 2012 in the Nansi Lake basin, the correlation and change between the water environmental quality and economic development were studied. Results showed that the GDP and wastewater emissions of point source in the Nansi Lake basin had an average annual growth of 7.30 and 7.68 %, respectively, from 2002 to 2012. The emissions of chemical oxygen demand (COD) and ammonia nitrogen (NH3-N) had the average annual decrease of 7.69 and 6.79 % in 2012, respectively, compared to 2002. Basin water quality overall improved, reaching the Class III of the "Environmental quality standards for surface water (GB3838-2002)," in which the main reason was that sewage treatment rate increased gradually and was above 90 % in 2012 (an increase of 10 % compared to 2002) with the progress of pollution abatement technology and the implementation of relevant policies and regulations. The contribution of water environmental pollution was analyzed from related cities (Ji'ning, Zaozhuang, Heze). Results indicated that Ji'ning had the largest contribution to water pollution of the Nansi Lake basin, and the pollutant from domestic sources accounted for a higher percentage compared to industrial sources. The wastewater, COD, and NH3-N mainly came from mining and washing of coal, manufacture of raw chemical materials and chemical products, papermaking industry, and food processing industry. According to the water pollution characteristics of the Nansi Lake basin, the basin pollution treatment strategy and prevention and treatment system were dissected to provide a scientific basis for prevention and control of lakeside point source pollution along the Nansi Lake. PMID:26545892
McTaggart, Lisa R.; Brown, Elizabeth M.; Richardson, Susan E.
2016-01-01
Blastomyces dermatitidis and Blastomyces gilchristii are dimorphic fungal pathogens that cause serious pulmonary and systemic infections in humans. Although their natural habitat is in the environment, little is known about their specific ecologic niche(s). Here, we analyzed 25 microsatellite loci from 169 strains collected from various regions throughout their known endemic range in North America, representing the largest and most geographically diverse collection of isolates studied to date. Genetic analysis of multilocus microsatellite data divided the strains into four populations of B. dermatitidis and four populations of B. gilchristii. B. dermatitidis isolates were recovered from areas throughout North America, while the B. gilchristii strains were restricted to Canada and some northern US states. Furthermore, the populations of both species were associated with major freshwater drainage basins. The four B. dermatitidis populations were partitioned among (1) the Nelson River drainage basin, (2) the St. Lawrence River and northeast Atlantic Ocean Seaboard drainage basins, (3) the Mississippi River System drainage basin, and (4) the Gulf of Mexico Seaboard and southeast Atlantic Ocean Seaboard drainage basins. A similar partitioning of the B. gilchristii populations was observed among the more northerly drainage basins only. These associations suggest that the ecologic niche where the sexual reproduction, growth, and dispersal of B. dermatitidis and B. gilchristii occur is intimately linked to freshwater systems. For most populations, sexual reproduction was rare enough to produce significant linkage disequilibrium among loci but frequent enough that mating-type idiomorphic ratios were not skewed from 1:1. Furthermore, the evolutionary divergence of B. dermatitidis and B. gilchristii was estimated at 1.9 MYA during the Pleistocene epoch. We suggest that repeated glaciations during the Pleistocene period and resulting biotic refugia may have provided the
Three-dimensional Numerical Analysis of a Liquid Metal MHD Generator
NASA Astrophysics Data System (ADS)
Yamada, Katsunori; Maeda, Tetsuhiko; Hasegawa, Yasuo; Okuno, Yoshihiro
Three-dimensional numerical analysis of a liquid metal MHD generator has been carried out. The three-dimensional structures of the electromagnetic field and fluid flow in the MHD generator have been clarified, and the effect of the electrode width on the performance has been also examined, taking account of the current flow in the electrode. Structures of the electromagnetic field and fluid flow are complicated owing to the three-dimensional current flow, induced magnetic field, and Lorentz force. The highest performance is found to be obtained when the width of electrode is equal to that of the generator. The performance predicted from three-dimensional analysis is somewhat lower than that from two-dimensional an