Basin analysis in a Tertiary delta by numerical modeling: Mahakam case study (Indonesia)
Burrus, J.; Brosse, E. ); Grosjean, Y.; Choppin de Janvry, G.; Oudin, J.L. ); Bessereau, G. )
1990-05-01
The evolution of the Mahakam delta is discussed on the basis of a quantitative reconstruction using the two-dimensional TEMISPACK software developed at Institut Francais du Petrole. The following steps are achieved. (1) An east-west 80-km-long regional seismic line tied on wells is used to establish a depth-section divided in 25 chronostratigraphic levels, and 40 vertical columns. Fifteen different lithologies are distinguished (between shales and sandstones, with variable total organic carbon), as interpreted from well data and seismic profiles. (2) Porosity-depth relations derived from log-data are used to backstrip the section and reconstruct the past geometries. The development of geopressures is investigated after calibration of the permeabilities on the observed lithologies. In particular, the authors account for the small-scale variations of the sandshale ratio by introducing a high anisotropy of the permeabilities. The model is shown to reproduce well observations such as depth at which geopressures appear, and gradient of pressure in the overpressured zone. The simulations show that the geopressures essentially are controlled by the distribution of the sandy layers, and are due to compaction disequilibrium (3) The generation of hydrocarbons simulated by a kinetic model and the migration (separate phase flow) of hydrocarbons is discussed. Boundary conditions and underconstrained parameters, such as capillary forces, past heat flow, etc., are discussed on the basis of a sensitivity analysis.
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.
Ichnofabric and basin analysis
Bottjer, D.J. ); Droser, M.L. )
1991-06-01
Utilization of ichnofabric indices for measuring recorded extent of bioturbation allows comparative studies of ichnofabric between different facies. In vertical sequences, measurements of ichnofabric indices can be normalized to percent of the total thickness measured for each ichnofabric index. These data can be presented as histograms, or ichnograms, when measurements are from strata deposited in a single genetically-defined sedimentary environment. Ichnograms can be used in conjunction with ichnofacies analysis to present a more complete summary of bioturbation in a sedimentary unit. Using a knowledge of the factors which contribute towards producing ichnofabric in different sedimentary environments, the range of possible ichnograms for any environment can be modeled. In addition to ichnograms, an average ichnofabric index also can be calculated as a useful summary characterization of the extent of bioturbation recorded in a sedimentary unit. Through measurement of ichnofabric indices, construction of ichnograms, and calculation of average ichnofabric index, broad-scale summary data are produced that can allow a more complete understanding of the physical and biological dynamics of sedimentary basins, especially when employed in conjunction with other basin analysis approaches.
NASA Astrophysics Data System (ADS)
Henderson, Michael
1997-08-01
The Numerical Analysis Objects project (NAO) is a project in the Mathematics Department of IBM's TJ Watson Research Center. While there are plenty of numerical tools available today, it is not an easy task to combine them into a custom application. NAO is directed at the dual problems of building applications from a set of tools, and creating those tools. There are several "reuse" projects, which focus on the problems of identifying and cataloging tools. NAO is directed at the specific context of scientific computing. Because the type of tools is restricted, problems such as tools with incompatible data structures for input and output, and dissimilar interfaces to tools which solve similar problems can be addressed. The approach we've taken is to define interfaces to those objects used in numerical analysis, such as geometries, functions and operators, and to start collecting (and building) a set of tools which use these interfaces. We have written a class library (a set of abstract classes and implementations) in C++ which demonstrates the approach. Besides the classes, the class library includes "stub" routines which allow the library to be used from C or Fortran, and an interface to a Visual Programming Language. The library has been used to build a simulator for petroleum reservoirs, using a set of tools for discretizing nonlinear differential equations that we have written, and includes "wrapped" versions of packages from the Netlib repository. Documentation can be found on the Web at "http://www.research.ibm.com/nao". I will describe the objects and their interfaces, and give examples ranging from mesh generation to solving differential equations.
Gravity Analysis of the Jeffera Basin, Tunisia
NASA Astrophysics Data System (ADS)
Mickus, K.; Gabtni, H.; Jallouli, C.
2004-12-01
Southern Tunisia consists of two main tectonic provinces: 1) the Saharan Platform and 2) the folded Atlasic domain, separated by the North Saharan Flexure. The Saharan Platform, which contains the Ghadames Basin and the Telemzane Arch, consists of gently dipping Paleozoic strata overlain by Triassic to Cretaceous sediments. The Atlasic domain consists of a thicker sequence of mainly Mesozoic and younger rock with less complete sequences of Paleozoic strata. Within the Atlasic domain are the still actively subsiding Chotts and Jeffera basins. The Jeffera basin, which occurs to the east of the Telemzane Arch contains at least eight kilometers of Paleozoic and younger sediment that were formed during numerous subsidence episodes since Carboniferous time. The Jeffera basin is dominated by tilted fault blocks that were formed during numerous tectonic episodes. Several unpublished seismic reflection profiles and well data exist for the Jeffera basin, however a deep structural analysis of the basin has not been published. We examined the existing gravity data in conjunction with available well and geologic data to determine structural features within the basin. The Bouguer gravity anomaly map shows that the Jeffera basin is dominated by a narrow northwest-trending gravity minimum. However, a more detailed analysis consisting of wavelength filtering and edge enhancements indicate that the structure of the basin is more complicated than indicated by the Bouguer gravity anomaly map. A residual gravity anomaly map indicates that the Jeffera basin consists of at least three and maybe four subbasins. Additionally, the Jeffera Fault marks the boundary between northwest-trending gravity anomalies to its northeast and east-trending anomalies over the Saharan Platform. The above observation is amplified by the construction of the enhanced horizontal derivatives (EHG) of both the complete Bouguer gravity and the residual gravity anomaly maps. The EHG maps highlight the lateral
Principles of Sedimentary Basin Analysis
NASA Astrophysics Data System (ADS)
Stanton, Robert J., Jr.
Basin analysis is the ultimate act of synthesis in stratigraphy. Its objective is to weave together the diverse strands of information in order to portray the tectonic evolution of a basin, its filling with sediments in a broad range of depositional environments, the subsequent diagenesis and lithification of these sediments, and the localization therein of mineral and petroleum resources. Thus, although the primary emphasis in basin analysis is stratigraphic and sedimentologic in nature, paleontologic, tectonic, and geophysical data, among others, are also integral components of the effort. It is scientifically challenging and, in practical terms, forms the foundation for the exploration for strata-bound resources. The wide range of topics that must be incorporated into a basin analysis requires that it be a group project of specialists and means that it is a difficult subject to teach or to present in a book.
BASIN: Beowulf Analysis Symbolic INterface
NASA Astrophysics Data System (ADS)
Vesperini, Enrico; Goldberg, David M.; McMillan, Stephen L. W.; Dura, James; Jones, Douglas
2013-08-01
BASIN (Beowulf Analysis Symbolic INterface) is a flexible, integrated suite of tools for multiuser parallel data analysis and visualization that allows researchers to harness the power of Beowulf PC clusters and multi-processor machines without necessarily being experts in parallel programming. It also includes general tools for data distribution and parallel operations on distributed data for developing libraries for specific tasks.
Numerical modelling of ground motion in the Taipei Basin: basin and source effects
NASA Astrophysics Data System (ADS)
Miksat, J.; Wen, K.-L.; Wenzel, F.; Sokolov, V.; Chen, C.-T.
2010-12-01
found from the analysis of observed earthquakes. These values clearly exceed the amplification values of about 2-3 obtained when applying standard 1-D site effect analysis. Our simulations for different earthquake positions show that ground motion depends strongly on earthquake location and fault orientation. Therefore, the application of average values of spectral amplification obtained from the analysis of recorded data from distant earthquakes with different azimuths and fault planes may significantly underestimate future ground motions of possible earthquakes on known faults close to the Taipei basin. The simulation of a small earthquake near the Taipei basin presented in this study will help to set up adequate simulation parameters for a possible large earthquake close to the Taipei basin. Such a simulation of a scenario earthquake close to the Taipei basin would allow to significantly improve hazard assessment as no observations of strong earthquakes in the vicinity of the basin exist.
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
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.
NASA Astrophysics Data System (ADS)
Moczo, P.; Kristek, J.; Galis, M.; Pazak, P.
2009-12-01
applicable to media with large Vp/Vs ratio and thus to real sedimentary basins. Surprisingly, FD_DS_PSG is the worst scheme for the lowest values of the Vp/Vs ratio. Errors of FD_DS_SG and FD_VS_SG are very close and small (relative to other schemes), and they are least sensitive to variation in Vp/Vs. In parallel with the numerical results and their analysis we compare the numerical schemes themselves in terms of their inherent structures and applied approximations. We also discuss properties of recent higher-order numerical schemes.
Geohistorical analysis of Paradox Basin
Lemke, L.D.
1985-05-01
The Paradox basin is an elongate sedimentary basin, asymmetric in profile, extending across common corners of Utah, Colorado, Arizona, and New Mexico. Subsidence of the basin began in Desmoinesian time and was coincident with the development of the ancestral Rocky Mountains. The Uncompahgre uplift formed the northeast boundary of the basin during Pennsylvanian and Permian times. Formation thickness and lithologies were obtained from lithologic and radioactivity logs from various parts of the basin. The stratigraphic column at each well, restored through the Upper Cretaceous, was back-stripped and decompacted to reconstruct its depositional history. Decompacted geohistory diagrams and residual (tectonic) subsidence curves were then generated for each well. The Mobil 1 McCormick well, drilled in 1977, penetrates Pennsylvanian strata beneath reverse-faulted granitic basement; this indicates that the basin was flexed down in response to pennsylvanian and Permian thrust faulting along the flank of the Uncompahgre uplift. However, close correspondence of the residual subsidence curves to theoretical thermal subsidence curves indicates that the basin formed by crustal extension. Consequently, development of the basin may have involved crustal stretching (transtensional.) beneath the basin floor, followed by thrusting (transpressional.) along the flank of the Uncompahgre uplift.
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 Simulation of Extent of Carbon Dioxide Plume Injected in the Gyeongsang Basin, Korea
NASA Astrophysics Data System (ADS)
Kihm, J.; Park, S.; Kim, J.
2012-12-01
A series of thermo-hydro-chemical numerical simulations was performed to evaluate extent of carbon dioxide plume injected in the Gyeongsang Basin, which is one of the prospective onshore sedimentary basins for geologic storage of carbon dioxide in Korea. The carbon dioxide plume extent is an important factor in estimating storage efficiency and thus storage capacity of carbon dioxide in a storage formation because it represents an actual volume of the storage formation, which is occupied by injected carbon dioxide. The carbon dioxide plume extent is also an essential component in risk analysis of geologic storage of carbon dioxide because most of thermo-hydro-mechanical-chemical responses to carbon dioxide injection occur within it. To evaluate impacts of injection scenarios (i.e., injection rate and period) of carbon dioxide and geological conditions (i.e., thickness and depth) and hydrogeochemical properties (i.e., porosity, intrinsic permeability, salt concentration in groundwater, and volume fraction of chlorite) of a storage formation on the carbon dioxide plume extent, a series of sensitivity tests was also performed. The numerical simulation results show that the carbon dioxide plume extent is significantly affected by such injection scenarios, geological conditions, and hydrogeochemical properties. The carbon dioxide plume extent increases as the injection rate (with a constant injection period) increases, and this trend does not change with time. The carbon dioxide plume extent decreases as the injection period (with a constant total injection amount) increases until about 50 years, while it is not sensitive to the injection period after about 50 years. The carbon dioxide plume extent also decreases as the thickness increases until about 100 years, while it is not sensitive to the thickness after about 100 years. In contrast, the carbon dioxide plume extent decreases as the depth increases, and this trend is intensified with time. On the other hand, the
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.
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…
Numerical modeling of the formation and structure of the Orientale impact basin
NASA Astrophysics Data System (ADS)
Potter, Ross W. K.; Kring, David A.; Collins, Gareth S.; Kiefer, Walter S.; McGovern, Patrick J.
2013-05-01
The Orientale impact basin is the youngest and best-preserved lunar multi-ring basin and has, thus, been the focus of studies investigating basin-forming processes and final structures. A consensus about how multi-ring basins form, however, remains elusive. Here we numerically model the Orientale basin-forming impact with the aim of resolving some of the uncertainties associated with this basin. By using two thermal profiles estimating lunar conditions at the time of Orientale's formation and constraining the numerical models with crustal structures inferred from gravity data, we provide estimates for Orientale's impact energy (2-9 × 1025 J), impactor size (50-80 km diameter), transient crater size (˜320-480 km), excavation depth (40-55 km), and impact melt volume (˜106 km3). We also analyze the distribution and deformation of target material and compare our model results and Orientale observations with the Chicxulub crater to investigate similarities between these two impact structures.
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.
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)
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
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)
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)
Chernov, Anton; Kurkin, Andrey; Pelinovsky, Efim; Yalciner, Ahmet; Zaytsev, Andrey
2010-05-01
A short cut numerical method for evaluation of the modes of free oscillations of the basins which have irregular geometry and bathymetry was presented in the paper (Yalciner A.C., Pelinovsky E., 2007). In the method, a single wave is inputted to the basin as an initial impulse. The respective agitation in the basin is computed by using the numerical method solving the nonlinear form of long wave equations. The time histories of water surface fluctuations at different locations due to propagation of the waves in relation to the initial impulse are stored and analyzed by the fast Fourier transform technique (FFT) and energy spectrum curves for each location are obtained. The frequencies of each mode of free oscillations are determined from the peaks of the spectrum curves. Some main features were added for this method and will be discussed here: 1. Instead of small number of gauges which were manually installed in the studied area the information from numerical simulation now is recorded on the regular net of the «simulation» gauges which was place everywhere on the sea surface in the depth deeper than "coast" level with the fixed presetted distance between gauges. The spectral analysis of wave records was produced by Welch periodorgam method instead of simple FFT so it's possible to get spectral power estimation for wave process and determine confidence interval for spectra peaks. 2. After the power spectral estimation procedure the common peak of studied seiche can be found and mean spectral amplitudes for this peak were calculated numerically by a Simpson integration method for all gauges in the basin and the mean spectral amplitudes spatial distribution map can be ploted. The spatial distribution helps to study structure of seiche and determine effected dangerous areas. 3. Nested grid module in the NAMI-DANCE - nonlinear shallow water equations calculation software package was developed. This is very important feature for complicated different scale (ocean
Retrieval, Analysis, and Display of Numeric Data.
ERIC Educational Resources Information Center
Berger, Mary C.; Wanger, Judith
1982-01-01
This introduction to online numeric database systems describes the types of databases associated with such systems, shows the major functions which they can perform (retrieval, analysis, display), and identifies the major characteristics of user interfaces. Examples of numeric database use are appended. (EJS)
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
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.
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)
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
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.
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…
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.
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.
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.
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
3-D-geomechanical-numerical model of the contemporary crustal stress state in the Alberta Basin
NASA Astrophysics Data System (ADS)
Reiter, K.; Heidbach, O.
2014-08-01
In the context of examining the potential usage of safe and sustainable geothermal energy in the Alberta Basin whether in deep sediments or crystalline rock, the understanding of the in-situ stress state is crucial. It is a key challenge to estimate the 3-D stress state at an arbitrary chosen point in the crust, based on sparsely distributed in-situ stress data. To address this challenge, we present a large-scale 3-D geomechanical-numerical model (700 km × 1200 km × 80 km) from a large portion of the Alberta Basin, to provide a 3-D continuous quantification of the contemporary stress orientations and stress magnitudes. To calibrate the model, we use a large database of in-situ stress orientation (321 SHmax) as well as stress magnitude data (981 SV, 1720 SHmin and 2 (+1) SHmax) from the Alberta Basin. To find the best-fit model we vary the material properties and primarily the kinematic boundary conditions of the model. This study focusses in detail on the statistical calibration procedure, because of the large amount of available data, the diversity of data types, and the importance of the order of data tests. The best-fit model provides the total 3-D stress tensor for nearly the whole Alberta Basin and allows estimation of stress orientation and stress magnitudes in advance of any well. First order implications for the well design and configuration of enhanced geothermal systems are revealed. Systematic deviations of the modelled stress from in-situ data are found for stress orientations in the Peace River- and the Bow Island Arch as well as for leak-off-test magnitudes.
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
Three-dimensional thermohaline numerical investigations within the Northeast German Basin
NASA Astrophysics Data System (ADS)
Kaiser, B. O.; Cacace, M.; Scheck-Wenderoth, M.
2013-12-01
The identification of geothermal target reservoirs for potential energy supply requires a regional understanding of the thermal setting of sedimentary basins. The Northeast German Basin (NEGB, in northern Germany) hosts a significant amount of groundwater and heat resources. However, the main physical transport processes responsible for these resources are still not completely understood. In Germany, the NEGB represents a complex heterogeneous geological system characterized by several stratified aquifer complexes of regional relevance. The sedimentary structure of the NEGB is affected by a thick Zechstein salt sequence structured in numerous salt pillows and diapirs piercing the overlying Mesozoic aquifers. At shallower depths, an embedded aquitard consisting of fine clayey deposits (Rupelian Clay) separates the Quaternary to late Tertiary freshwater aquifer from the underlying Mesozoic saline aquifers. An important feature is that discontinues within this aquitard exist in areas where the Rupelian clay was not deposited or has been eroded leading to hydraulic connections between the upper and lower aquifers (hydrogeological windows). As a consequence of both salt diapirism and due to existing geological discontinuities in the Rupelian aquitard (hydrogeological windows) the depths and thicknesses of the major Mesozoic aquifers vary widely on the basin scale. Moreover groundwater in the vicinity around salt structures may be subjected to lateral fluid density gradients triggered by abrupt variations in the fluid temperature and salinity. As a result, a complex groundwater flow field is expected within the basin system which is affected both by the complex geometry of the different horizons (aquifers and aquitards) as well as by external (hydraulic gradient) and internal (buoyancy) driving forces. Within the project GeoEn (Joint Research Project on GeoEnergy Research) three-dimensional thermohaline numerical simulations are carried out to discriminate interrelated
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.
Ahmad, Zulfiqar; Ashraf, Arshad; Fryar, Alan; Akhter, Gulraiz
2011-02-01
The integration of the Geographic Information System (GIS) with groundwater modeling and satellite remote sensing capabilities has provided an efficient way of analyzing and monitoring groundwater behavior and its associated land conditions. A 3-dimensional finite element model (Feflow) has been used for regional groundwater flow modeling of Upper Chaj Doab in Indus Basin, Pakistan. The approach of using GIS techniques that partially fulfill the data requirements and define the parameters of existing hydrologic models was adopted. The numerical groundwater flow model is developed to configure the groundwater equipotential surface, hydraulic head gradient, and estimation of the groundwater budget of the aquifer. GIS is used for spatial database development, integration with a remote sensing, and numerical groundwater flow modeling capabilities. The thematic layers of soils, land use, hydrology, infrastructure, and climate were developed using GIS. The Arcview GIS software is used as additive tool to develop supportive data for numerical groundwater flow modeling and integration and presentation of image processing and modeling results. The groundwater flow model was calibrated to simulate future changes in piezometric heads from the period 2006 to 2020. Different scenarios were developed to study the impact of extreme climatic conditions (drought/flood) and variable groundwater abstraction on the regional groundwater system. The model results indicated a significant response in watertable due to external influential factors. The developed model provides an effective tool for evaluating better management options for monitoring future groundwater development in the study area. PMID:20213054
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.
Numerical and experimental analysis of a retrievable offshore loading facility
Sterndorff, M.J.; O`Brien, P.
1995-12-31
ROLF (Retrievable Offshore Loading Facility) has been proposed as an alternative offshore oil export tanker loading system for the North Sea. The system consists of a flexible riser ascending from the seabed in a lazy wave configuration to the bow of a dynamically positioned tanker. In order to supplant and support the numerical analyses performed to design the system, an extensive model test program was carried out in a 3D offshore basin at scale 1:50. A model riser with properties equivalent to the properties of the oil filled prototype riser installed in seawater was tested in several combinations of waves and current. During the tests the forces at the bow of the tanker and at the pipeline end manifold were measured together with the motions of the tanker and the riser. The riser motions were measured by means of a video based 3D motion monitoring system. Of special importance was accurate determination of the minimum bending radius for the riser. This was derived based on the measured riser motions. The results of the model tests were compared to numerical analyses by an MCS proprietary riser analysis program.
Generalized Diffuse Field Within a 2d Alluvial Basin: a Numerical Example
NASA Astrophysics Data System (ADS)
Molina Villegas, J.; Baena, M.; Piña, J.; Perton, M.; Suarez, M.; Sanchez-Sesma, F. J.
2013-05-01
Since the pioneering work of Aki (1957), the seismic noise has been used to infer the wave velocity distribution of soil formations. Later, diffuse-field concepts from room acoustics began to be used in elastodynamics by Weaver (1982) and flourished in many applications thanks to the contributions of Campillo and coworkers. It was established that diffusion like regimes are obtained when the field is produced by equipartitioned, uniform illumination. Within an elastodynamic diffuse-field the average correlation of the displacement field between two stations is proportional to the Green function of the system for those points. Usually, the surface waves can be interpreted by means of the retrieved Green function, from which very important information about the properties in depth can be obtained. Seismic noise and coda are frequently considered as diffuse-fields. This assumption is well supported by ideas of multiple scattering of waves and the resultant energy equipartition. There are few examples of numerically generated diffuse-fields. Some are based on random distributed forces (e.g. Sánchez-Sesma et al., 2006), while others used a set of plane waves with varying incidence angles and polarization (e.g. Sánchez-Sesma and Campillo 2006; Kawase et al. 2011). In this work we generate numerically a diffuse field within the Kawase and Aki (1989) 2D model using a random set of independent and uncorrelated incident plane P, SV and Rayleigh waves. For the simulations we use the indirect boundary element method (IBEM). Thus, we obtained the Green function for pairs of receivers by averaging correlations between different stations on the surface. In order to validate our results we compute the model's Green function as the response for a unit point load using the IBEM. Our numerical experiment provides guidelines for actual calculations of earthquakes in real alluvial basins.
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.
Stilling Basin Performance Analysis by ADV
NASA Astrophysics Data System (ADS)
Aleyasin, Sobhan; Fathi, Nima; Vorobieff, Peter
2014-11-01
The outlet flow from dams, channels, and pipes, as well as the river flow, can cause damage to the bed of the river or channel and cause scouring of structures such as the saddles of bridges, because of the huge amount of the kinetic energy carried by the flow. One of the ways to dissipate this energy is via the use of stilling basins, which are structures that calm the flow. Here we present a study of one type of stilling basins for pipe outlets based on a widely used standard. During the study, splitters and cellular baffles were placed in the stilling basin, and their locations were changed to assess their effect on the flow dissipation. Velocity at several locations in the basin was measured via acoustic Doppler velocimetry (ADV) for different Froude numbers to investigate the effect of flow rate and inlet velocity. Based on the findings of the experiments, we make several suggestions regarding the efficiency and geometry of stilling basins.
Phytoremediation of metals: a numerical analysis.
Lugli, Francesco; Mahler, Claudio Fernando
2015-01-01
A finite element code was used for investigating the effect of some relevant characteristics of a phytoremediation project (crop type and density, presence of an irrigation system, soil capping and root depth). The evolution of the plume of contamination of Cd2+, Pb2+, and Zn2+ was simulated taking into account reactive transport and root processes. The plant contaminant uptake model was previously calibrated using data from greenhouse experiments. The simulations adopted pedological and climatological data representative of a sub-tropical environment. Although the results obtained were specific for the proposed scenario, it was observed that, for more mobile contaminants, poor water conditions favor stabilization but inhibit plant extraction. Otherwise an irrigation system that decreases crop water stress had an opposite effect. For less mobile contaminants, the remediation process did not have appreciable advantages. Despite its simplifying assumptions, particularly about contaminant sorption in the soil and plant system, the numerical analysis provided useful insight for the phytoextraction process important in view of field experiments. PMID:25397982
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)
Cui, Y.
2015-12-01
In order to study surface water and groundwater exchange and renewal capacity of groundwater system of Qaidam Basin, inland northwest China, TOUGH2 (Transport of Unsaturated Groundwater and Heat 2) simulation software was used to establish a two-dimensional variable saturated numerical model of a typical cross-section from the Nuomuhong river to the Amunike mountain. According to previous results, evaporation is a function of soil saturation given as an upper boundary to characterize water transport near surface through iterative calculation. Parameters were calibrated with 52 groundwater observation data by trial-and-error method. Particle tracking and isotopic dating results were combined to simulate groundwater age and calibrate models. The results showed that the typical profile of Qaidam basin can be divided into three lumped groundwater flow systems: (1) The circulation depth (CD) of local groundwater flow system is about 200m, where discharge in this lumped system accounts for 74.4% of the total amount of discharge (TAD), of which spring overflow constitutes large fraction. Groundwater age is generally less than 500 years and renewal rate is 1.13% a-1; (2) The CD of middle flow system can reach 800m, where it takes up 18.5% of TAD, evaporation and river overflows is the main outlet of discharge. Groundwater age is generally less than 10ka and renewal rate is 0.094% a-1; (3) The CD of regional flow system is from 1000 to 1500m. It accounts for 7.1% of TAD, of which evaporation is the largest component. Groundwater age is from 10ka to 50ka and renewal rate of which is 0.0074% a-1. Sulingguole river is the discharge area of regional groundwater system, the age of which is greater than 30ka. The method used here can obtain the renewal capacity of groundwater system and better reflect regional circulation characteristics, which have certain significance for the urgent study of regional groundwater circulation and flow systems in areas with limited available data.
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.
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.
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.
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.
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
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
An object-oriented expert system for sedimentary basin analysis
Miller, B.M. )
1991-08-01
Some of the basic earth-science problems that span industry, academia, and the government, and are likely candidates for the application of knowledge-based expert systems, pertain to energy and mineral resource studies. Most of the world's energy resources and many of its metallic and mineral resources are derived from complex sources in sedimentary basins. A comprehensive basin analysis requires an understanding of data from many specialties including sedimentology, stratigraphy, geophysics, structural geology, and geochemistry. Such as integrated analysis is almost impossible without a computer. Research efforts in the US Geological Survey are currently being directed at exploring the feasibility of applying expert systems and knowledge acquisition techniques to the design and development of a global system of classification and geological analysis of sedimentary basins to assess their petroleum potential. The primary objective is the design of a prototype object-oriented expert system, interfaced with a Geographic Information System (GIS), that captures both the logic used to define the geologic concepts and the reasoning under uncertainty that enables geologists to understand and reconstruct geologic history of a sedimentary basins. The systems are designed to analyze the traditional concepts of source, reservoir, and trapping mechanism; to help diagnose geologic conditions favorable for the occurrence of petroleum or other energy resources; and to assist in assessing these resources. The design and content of the expert systems program is discussed for application to basin analysis studies to aid in petroleum resource assessment.
Numerical analysis of a vortex controlled diffuser
NASA Technical Reports Server (NTRS)
Spall, Robert E.
1993-01-01
A numerical study of a prototypical vortex controlled diffuser is performed. The basic diffuser geometry consists of a step expansion in a pipe of area ratio 2.25:1. The incompressible Reynolds averaged Navier-Stokes equations, employing the K-epsilon turbulence model, are solved. Results are presented for bleed rates ranging from 1 to 7 percent. Diffuser efficiencies in excess of 80 percent are obtained. Reattachment lengths are reduced by a factor of up to 3. These results are in qualitative agreement with previous experimental work. However, differences in some basic details of experimentally observed and the present numerically generated flowfields exist. The effect of swirl is also investigated.
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
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.
Microfabric analysis of the Appalachian basin Williamson and Willowvale shales
Burkins, D.L.; Woodard, M. . Geology Dept.)
1993-03-01
Shale samples from the Williamson and Willovale formations (Upper Llandoverian, Silurian) were studied to determine the relationship of microfabric (particle orientation) to sedimentary environment and processes. The shales were sampled along a traverse from Utica to Rochester, New York in the Appalachian foreland basin. Samples were taken from proximal and distal parts of the basin and analyzed using a scanning electron microscope (SEM) and using thin sections to determine the relationship between microfabric and basin position. Results show samples taken from the proximal part of the basin contain large amounts of silt grains, random orientation of clay flakes, and a high degree of bioturbation. Basinward, the samples become less silty, less bioturbated, and have more preferred orientation of clay flakes. The samples at the basin axis show the highest degree of preferred orientation and contain no silt grains. It can be concluded that the shale fabrics vary basinward and microfabric analysis is useful in determining the relative position of samples within a sedimentary basin.
New technique for structural analysis of low-relief basins
Berger, Z.
1986-05-01
A new technique for structural analysis of low-relief basins integrates Landsat data with other geologic data sets such as gravity, magnetic, subsurface, and production data. Five analytical steps are recommended, and examples are supported by surface and subsurface controls. These steps are: (1) analyzing exposed structures that form the basin margin; (2) recognizing structural trends within the basin; (3) recognizing buried and obscured structures within the basin; (4) constructing an exploration model; and (5) generating new leads for the entire region. Examples cited are from various low-relief basins such as the Powder River, and the Central Basin platform of west Texas. Surface expressions of buried and obscured structures are attributed to differential compaction, loading, structural reactivation, and other processes related to abnormal flows of ground and surface waters near the structures. These well-recognized processes occur under various climatic and surface conditions. Landsat data can be used in low-relief frontier areas as a reconnaissance tool to identify regional trends, structural types, and potentially prospective structures. These data can also be used in low-relief mature areas to locate subtle structures not identified by other exploration techniques.
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.
Nurmi, R.D.
1984-12-01
The history of the Michigan basin (Early Ordovician to Early Devonian) is that of a nonuniformly subsiding basin, with the Michigan basin, at times, nearly disappearing as either a topographic feature or a depositional center. This history is interpreted from the analysis of lithostratigraphic units, time stratigraphic features, and log formats (term by J. Forgotson). These units are defined for wells throughout the Michigan basin, and they extended eastward into the Appalachian basin. The definition and thickness mapping of these lithostratigraphic units and formats are accomplished using well cuttings, cores, and wire-line geophysical well logs. From these data, it is possible to interpret the major aspects of both the subsidence and depositional history of the basin. During deposition of both the Trenton limestones and Early Silurian carbonates and shales, the Michigan basin behaved as if it were part of the greater Appalachian basin, whereas prior to the deposition of the Trenton (Middle Ordovician) and during Middle and Late Silurian, the Michigan basin was an entity separate from, and with an apparent structural independence of, the greater Appalachian basin. The structural and topography of the Trenton prior to the deposition of the Utica Shale was mapped throughout Michigan to provide insight into the nature of petroleum entrapment in the Trenton formation. The structural entrapment of petroleum in southeast Michigan contrasts with the combination diagenetic to structural Albio-Scipio trend of south-central Michigan. Evidence is available that more of these two types of traps occur in unproducing areas of the Michigan basin.
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.
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
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.
Floods in the Niger basin - analysis and attribution
NASA Astrophysics Data System (ADS)
Aich, V.; Koné, B.; Hattermann, F. F.; Müller, E. N.
2014-08-01
This study addresses the increasing flood risk in the Niger basin and assesses the damages that arise from flooding. Statistics from three different sources (EM-DAT, Darthmouth Flood Observatory, NatCat Munich RE) on people affected by floods show positive trends for the entire basin beginning in the 1980s. An assessment of four subregions across the Niger basin indicates even exponential trends for the Sahelian and Sudanian regions. These positive trends for flooding damage match up to a time series of annual maximum discharge (AMAX): the strongest trends in AMAX are detected in the Sahelian and Sudanian regions, where the population is also increasing the fastest and vulnerability generally appears to be very high. The joint effect of these three factors can possibly explain the exponential increase in people affected by floods in these subregions. In a second step, the changes in AMAX are attributed to changes in precipitation and land use via a data-based approach within a hypothesis-testing framework. Analysis of rainfall, heavy precipitation and the runoff coefficient shows a coherent picture of a return to wet conditions in the basin, which we identify as the main driver of the increase in AMAX in the Niger basin. The analysis of flashiness (using the Richards-Baker Index) and the focus on the "Sahel Paradox" of the Sahelian region reveal an additional influence of land-use change, but it seems minor compared to the increase in precipitation.
Ground water budget analysis and cross-formational leakage in an arid basin.
Hutchison, William R; Hibbs, Barry J
2008-01-01
Ground water budget analysis in arid basins is substantially aided by integrated use of numerical models and environmental isotopes. Spatial variability of recharge, storage of water of both modern and pluvial age, and complex three-dimensional flow processes in these basins provide challenges to the development of a good conceptual model. Ground water age dating and mixing analysis with isotopic tracers complement standard hydrogeologic data that are collected and processed as an initial step in the development and calibration of a numerical model. Environmental isotopes can confirm or refute a priori assumptions of ground water flow, such as the general assumption that natural recharge occurs primarily along mountains and mountain fronts. Isotopes also serve as powerful tools during postaudits of numerical models. Ground water models provide a means of developing ground water budgets for entire model domains or for smaller regions within the model domain. These ground water budgets can be used to evaluate the impacts of pumping and estimate the magnitude of capture in the form of induced recharge from streams, as well as quantify storage changes within the system. The coupled analyses of ground water budget analysis and isotope sampling and analysis provide a means to confirm, refute, or modify conceptual models of ground water flow.
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.
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.
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
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.
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)
NASA Astrophysics Data System (ADS)
Son, Byeong-Kook; Lee, Seul-A.; Park, Mee-Sook
2015-04-01
Petroleum system modeling calculates and visualizes how and when hydrocarbons generate, migrate, and accumulate in a sedimentary basin. Therefore, it can be used effectively to predict the future prospects of oil and gas based on the understanding of the petroleum system in time and space. The petroleum system modeling was performed on the Sora Basin which is a small Cenozoic basin located offshore southern Korea, also including the offshore area of western Kyushu, Japan. Oil and gas shows were detected in two wells drilled in the basin, indicating that petroleum systems are present in the basin. Input parameters were selected from the well data as well as previous geological and geophysical studies for the 1-D model, from which thermal parameters such as heat flow and thermal maturity are also calculated and applied to 2-D model. The 2-D modeling was performed on an E-W seismic section across the basin from western margin in the Korea Block to eastern margin in Japanese Block. The PetroMod software was employed in the 2-D modeling, and stratigraphy, including lithology and organic content, was obtained from the wells and previous geological studies. 2-D modeling shows that hydrocarbons were expelled from the pod of the Eocene source rock in the Miocene time. The hydrocarbons migrate vertically along faults to the upper Oligocene sandstone formation, rather than the updip migrations along the sandstone bed, and hence form small-sized accumulations in the upper part of the sandstone formation. 3-D model was also performed based on depth maps of each formation in the Sora basin. Hydrocarbons are generated and expelled from the pod of the source rock of Eocene formation from 32Ma. In addition, the 3-D model shows that the hydrocarbon migrates northwestward and eastward in the carrier bed of sandstone. The petroleum models indicate that only a small amount of hydrocarbons are accumulated in the reservoir formation, probably due to small size of the basin and low degree
Sampling and Analysis Plan for the 105-N Basin Water
R.O. Mahood
1997-12-31
This sampling and analysis plan defines the strategy, and field and laboratory methods that will be used to characterize 105-N Basin water. The water will be shipped to the 200 Area Effluent Treatment Facility for treatment and disposal as part of N Reactor deactivation. These analyses are necessary to ensure that the water will meet the acceptance criteria of the ETF, as established in the Memorandum of Understanding for storage and treatment of water from N-Basin (Appendix A), and the characterization requirements for 100-N Area water provided in a letter from ETF personnel (Appendix B)
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
Manufacturing in space: Fluid dynamics numerical analysis
NASA Technical Reports Server (NTRS)
Robertson, S. J.; Nicholson, L. A.; Spradley, L. W.
1982-01-01
Numerical computations were performed for natural convection in circular enclosures under various conditions of acceleration. It was found that subcritical acceleration vectors applied in the direction of the temperature gradient will lead to an eventual state of rest regardless of the initial state of motion. Supercritical acceleration vectors will lead to the same steady state condition of motion regardless of the initial state of motion. Convection velocities were computed for acceleration vectors at various angles of the initial temperature gradient. The results for Rayleigh numbers of 1000 or less were found to closely follow Weinbaum's first order theory. Higher Rayleigh number results were shown to depart significantly from the first order theory. Supercritical behavior was confirmed for Rayleigh numbers greater than the known supercritical value of 9216. Response times were determined to provide an indication of the time required to change states of motion for the various cases considered.
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.
Numerical analysis of a thermal deicer
NASA Technical Reports Server (NTRS)
Wright, W. B.; Keith, T. G., Jr.; Dewitt, K. J.
1992-01-01
An algorithm has been developed to numerically model the concurrent phenomena of two-dimensional transient heat transfer, ice accretion and ice shedding which arise from the use of an electrothermal pad. The Alternating Direction Implicit method is used to simultaneously solve the heat transfer and accretion equations occurring in a multilayered body covered with ice. In order to model the phase change between ice and water, a technique was used which assumes a phase for each node. This allows the equations to be linearized such that a direct solution is possible. This technique requires an iterative procedure to find the correct phase at each node. The computer program developed to find this solution has been integrated with the NASA/Lewis flow/trajectory code LEWICE.
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.
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.
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.
Numerical analysis for finite Fresnel transform
NASA Astrophysics Data System (ADS)
Aoyagi, Tomohiro; Ohtsubo, Kouichi; Aoyagi, Nobuo
2016-10-01
The Fresnel transform is a bounded, linear, additive, and unitary operator in Hilbert space and is applied to many applications. In this study, a sampling theorem for a Fresnel transform pair in polar coordinate systems is derived. According to the sampling theorem, any function in the complex plane can be expressed by taking the products of the values of a function and sampling function systems. Sampling function systems are constituted by Bessel functions and their zeros. By computer simulations, we consider the application of the sampling theorem to the problem of approximating a function to demonstrate its validity. Our approximating function is a circularly symmetric function which is defined in the complex plane. Counting the number of sampling points requires the calculation of the zeros of Bessel functions, which are calculated by an approximation formula and numerical tables. Therefore, our sampling points are nonuniform. The number of sampling points, the normalized mean square error between the original function and its approximation function and phases are calculated and the relationship between them is revealed.
Numerical analysis for finite Fresnel transform
NASA Astrophysics Data System (ADS)
Aoyagi, Tomohiro; Ohtsubo, Kouichi; Aoyagi, Nobuo
2016-08-01
The Fresnel transform is a bounded, linear, additive, and unitary operator in Hilbert space and is applied to many applications. In this study, a sampling theorem for a Fresnel transform pair in polar coordinate systems is derived. According to the sampling theorem, any function in the complex plane can be expressed by taking the products of the values of a function and sampling function systems. Sampling function systems are constituted by Bessel functions and their zeros. By computer simulations, we consider the application of the sampling theorem to the problem of approximating a function to demonstrate its validity. Our approximating function is a circularly symmetric function which is defined in the complex plane. Counting the number of sampling points requires the calculation of the zeros of Bessel functions, which are calculated by an approximation formula and numerical tables. Therefore, our sampling points are nonuniform. The number of sampling points, the normalized mean square error between the original function and its approximation function and phases are calculated and the relationship between them is revealed.
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
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.
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 analysis of the orthogonal descent method
Shokov, V.A.; Shchepakin, M.B.
1994-11-01
The author of the orthogonal descent method has been testing it since 1977. The results of these tests have only strengthened the need for further analysis and development of orthogonal descent algorithms for various classes of convex programming problems. Systematic testing of orthogonal descent algorithms and comparison of test results with other nondifferentiable optimization methods was conducted at TsEMI RAN in 1991-1992 using the results.
Basin analysis studies of lower Paleozoic rocks, Powder River basin, Wyoming and Montana
Macke, D.L.
1988-07-01
The lower Paleozoic (Cambrian through Mississippian) sedimentary rocks of the Powder River basin represent nearly half of Phanerozoic time, yet they remain virtually unexplored in the subsurface. Rocks of the same age in the Big Horn and Williston basins and in the Central Montana trough have produced much oil and gas, as have the overlying Pennsylvanian strata of the Powder River basin. A synthesis of published stratigraphic information, together with a regional analysis of sedimentary sequences, has been undertaken to evaluate the economic potential of the lower Paleozoic formations. The lack of an economic impetus to study these rocks has hampered the development of precise depositional models for these sequences. Furthermore, the depths of prospective beds, as well as long-standing misconceptions about the regional stratigraphy, have also served to restrain exploration. Stratigraphic studies have documented a succession of marine transgressions and regressions on the flanks of a highland in southeastern Wyoming. The highland persisted as a subdued geographic feature through most of early Paleozoic time, until it rose at the end of the Mississippian. Erosion during the Late Silurian and Devonian removed much of the depositional record in the area, but onlap can be demonstrated with relative certainty for Ordovician and Mississippian rocks. The repetition of sedimentologic features indicates persistent geologic controls in the region and suggests that these paleoenvironments might provide good targets for exploration.
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
NASA Astrophysics Data System (ADS)
Reiter, K.; Heidbach, O.
2014-11-01
In the context of examining the potential usage of safe and sustainable geothermal energy in the Alberta Basin, whether in deep sediments or crystalline rock, the understanding of the in situ stress state is crucial. It is a key challenge to estimate the 3-D stress state at an arbitrarily chosen point in the crust, based on sparsely distributed in situ stress data. To address this challenge, we present a large-scale 3-D geomechanical-numerical model (700 km × 1200 km × 80 km) from a large portion of the Alberta Basin, to provide a 3-D continuous quantification of the contemporary stress orientations and stress magnitudes. To calibrate the model, we use a large database of in situ stress orientation (321 SHmax) as well as stress magnitude data (981 SV, 1720 Shmin and 2 (+11) SHmax) from the Alberta Basin. To find the best-fit model, we vary the material properties and primarily the displacement boundary conditions of the model. This study focusses in detail on the statistical calibration procedure, because of the large amount of available data, the diversity of data types, and the importance of the order of data tests. The best-fit model provides the total 3-D stress tensor for nearly the whole Alberta Basin, and allows estimation of stress orientation and stress magnitudes in advance of any well. First-order implications for the well design and configuration of enhanced geothermal systems are revealed. Systematic deviations of the modelled stress from the in situ data are found for stress orientations in the Peace River and the Bow Island Arch as well as for leak-off test magnitudes.
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.
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.
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
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.
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.
Sampling and Analysis Plan for K Basins Debris
WESTCOTT, J.L.
2000-06-21
This Sampling and Analysis Plan presents the rationale and strategy for sampling and analysis activities to support removal of debris from the K-East and K-West Basins located in the 100K Area at the Hanford Site. This project is focused on characterization to support waste designation for disposal of waste at the Environmental Restoration Disposal Facility (ERDF). This material has previously been dispositioned at the Hanford Low-Level Burial Grounds or Central Waste Complex. The structures that house the basins are classified as radioactive material areas. Therefore, all materials removed from the buildings are presumed to be radioactively contaminated. Because most of the materials that will be addressed under this plan will be removed from the basins, and because of the cost associated with screening materials for release, it is anticipated that all debris will be managed as low-level waste. Materials will be surveyed, however, to estimate radionuclide content for disposal and to determine that the debris is not contaminated with levels of transuranic radionuclides that would designate the debris as transuranic waste.
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.
NASA Astrophysics Data System (ADS)
Tallman, A. A.; Richards, K. E.; Stringer, A. C.; Weaver, J.; Daus, A.; Robinson, J. C.
2008-12-01
Geomatrix conducted a hydrogeologic assessment of the Inarajan and Tinaga River basins in southern Guam to develop a conceptual understanding of groundwater flow and occurrence in support of design, construction, and operation of a regional municipal landfill. Few previous hydrologic studies have focused on southern Guam, and thus this study provided the first detailed comprehensive assessment of groundwater and surface water conditions in the area. Data collected from an extensive field program, along with previous investigations were used to develop a hydrogeologic conceptual model describing regional and site geology, hydrostratigraphy, and groundwater and surface water flow. A three-dimensional numerical groundwater flow model of the system was developed using MODFLOW-SURFACT. The model was used to test various alternative conceptualizations and to provide a tool to evaluate landfill design and potential impacts to water resources from construction and operation of the landfill. The nature of the local watershed systems allowed for design of a basin-scale model. Historic USGS daily discharge measurements on the Inarajan and Tinaga Rivers coupled with historic precipitation records facilitated the basin scale approach. The model was calibrated to both steady state and transient conditions allowing for simulation of groundwater flow under a variety of conditions. Following calibration, predictive simulations were conducted to assess various aspects of landfill construction. The primary finding of the predictive assessments was that elimination of areal recharge resulting from construction of the landfill will cause a dramatic lowering of the water table in the weathered and fractured pyroclastic units that underlie the site. In addition, construction of the landfill will likely result in some reduction in stream base flow. Discharge of storm water runoff from the landfill into adjacent wetlands will mitigate some of the predicted impacts to base flow and
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.
Drought Analysis for River Basins, Using the Hydrological Model SIMGRO
NASA Astrophysics Data System (ADS)
Querner, E.; van Lanen, H.; Rhebergen, W.
2009-05-01
Drought is a recurring and worldwide phenomenon, with spatial and temporal characteristics that vary significantly from one region to another. Drought has major impacts on society and affects among others the environment and the economy. Impacts are likely to increase with time as societies demands higher services for water and the environment. This will even be more pronounced in the coming decades with the projected climate change, i.e. droughts are becoming more severe in large parts of the world. The prediction of droughts is an essential part of impact assessment for current and future conditions, as part of integrated land and water management. An important question is how changes in meteorological drought will propagate into hydrological droughts in terms of changes in the groundwater system or in the river flow. The objective of our study is to develop and test tools that quantify the space-time development of droughts in a river basin. The spatial aspect of a hydrological drought (spatially-distributed recharge and groundwater heads), in a river basin brings different challenges with respect to describing the characteristics of a drought, such as: onset, duration, severity and extend. We used the regional hydrological model SIMGRO as a basis to generate the necessary data for the drought analysis. SIMGRO is a distributed physically-based model that simulates regional transient saturated groundwater flow, unsaturated flow, actual evapotranspiration, sprinkler irrigation, stream flow, groundwater and surface water levels as a response to rainfall, reference evapotranspiration, and groundwater abstraction. The model is used within the GIS environment Arc-View, which enables the use of digital data, such as soil map, land use, watercourses, as input data for the model. It is also a tool for analysis, because interactively data and results can be presented, as will be shown. Droughts in different hydrological variables (recharge, groundwater heads, river flow
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.
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)
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
NASA Astrophysics Data System (ADS)
Petersen, K. D.; Nielsen, S. B.
2007-12-01
The North Sea sedimentary basin contains more than 3km of post Mid-Jurassic sediments. These are located in a trilete graben system consisting of the Moray Firth and the Viking and Central grabens, but also in a broad region surrounding the grabens, corresponding to the post-mid Cretaceous sediment deposits During the Mid- Jurassic the area was exposed to volcanism, domal regional uplift and erosion, followed by crustal thinning and normal faulting in the grabens. We use a numerical model considering 3D thermal evolution, flexural isostasy, erosion, sedimentation and compaction together with isopach data to simulate the geodynamic evolution of the area since the Mid-Jurassic. Our modelling studies show that the broad distribution of post Jurassic sediments cannot be explained by uniform stretching in the graben areas alone. Regional Mid-Jurassic thinning of the subcrustal lithosphere producing first uplift and erosion and later accommodation space for Cretaceous and Cenozoic sediments is also required. The uniform crustal thinning factor in the grabens amounts to a maximum of 1.14. The required subcrustal lithospheric thinning amounts to about 15 km. Our results are in accordance with observations from recent rift systems such as the Rhine Graben, Eastern Africa and the Baikal Rift, which show that crustal thinning is restricted to the graben areas while thinning of the subcrustal lithosphere (up to 100 km) and the associated domal surface uplift are more regionally distributed.
NASA Astrophysics Data System (ADS)
Petersen, K. D.; Nielsen, S. B.
2004-12-01
The North Sea sedimentary basin contains more than 3km of post Mid-Jurassic sediments. These are located in a trilete graben system consisting of the Moray Firth and the Viking and Central grabens, but also in a broad region surrounding the grabens, corresponding to the post-mid Cretaceous sediment deposits During the Mid- Jurassic the area was exposed to volcanism, domal regional uplift and erosion, followed by crustal thinning and normal faulting in the grabens. We use a numerical model considering 3D thermal evolution, flexural isostasy, erosion, sedimentation and compaction together with isopach data to simulate the geodynamic evolution of the area since the Mid-Jurassic. Our modelling studies show that the broad distribution of post Jurassic sediments cannot be explained by uniform stretching in the graben areas alone. Regional Mid-Jurassic thinning of the subcrustal lithosphere producing first uplift and erosion and later accommodation space for Cretaceous and Cenozoic sediments is also required. The uniform crustal thinning factor in the grabens amounts to a maximum of 1.14. The required subcrustal lithospheric thinning amounts to about 15 km. Our results are in accordance with observations from recent rift systems such as the Rhine Graben, Eastern Africa and the Baikal Rift, which show that crustal thinning is restricted to the graben areas while thinning of the subcrustal lithosphere (up to 100 km) and the associated domal surface uplift are more regionally distributed.
Analysis of water level variations in Brazilian basins using GRACE
NASA Astrophysics Data System (ADS)
Matos, A.; Blitzkow, D.; Almeida, F.; Costa, S.; Campos, I.; Barbosa, A.
2012-01-01
A comparison between daily
NASA Astrophysics Data System (ADS)
Pfunt, Helena; Houben, Georg; Himmelsbach, Thomas
2016-09-01
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.
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.
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.
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.)
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…
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 model and analysis of transistors with polysilicon emitters
NASA Astrophysics Data System (ADS)
Yu, Z.
With the advent of Very Large Scale Integration (VLS) technology, innovative bipolar devices with shallow junctions and high performances are being developed both for silicon and compound semiconductor materials. In the composite structure, such as HBJT (Heterojunction Bipolar Junction Transistor), the device characteristics are controlled not only by the doping profile but also by the composition of the structure. A complete physical and numerical model was developed to handle the carrier transport in such composite structure. An analytical approach (the introduction of an effective recombination velocity) to analyze carrier transport in the emitter of the bipolar transistor is discussed. Both analytical and numerical methods are then applied to the analysis of the device characteristics of transistors with polysilicon emitters. Good agreement between simulations and experimental results is achieved, and a regime of carrier distribution in the base space charge region is revealed. The numerical implementation of the model--a general purpose, one dimensional device simulation program (SEDAN) is briefly discussed.
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.
Morphometric analysis of a subtropical Andean basin (Tucumán, Argentina)
NASA Astrophysics Data System (ADS)
Mesa, L. M.
2006-09-01
A morphometric analysis was done to determine the drainage characteristics of Lules River basin using land-sat imageries and topographical maps. This catchment was divided into seven sub-basins for the analysis: Liquimayo, Hoyada, Ciénaga, De Las Tablas, Siambón, Potrerillo and San Javier. Yungas ecoregion covers almost all the watershed. The drainage patterns of the sub-basins are dendritic and parallel. The basin includes seventh order stream and lower streams order mostly dominate the basin. The development of stream segments is affected by slope and local relief. The mean bifurcation ratio indicates that the drainage pattern is not much influenced by geological structures. The shape parameters also reveal the elongation of the basin and sub-basins.
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.
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
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.
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.
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.
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)
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
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.
Recent advances in numerical analysis of structural eigenvalue problems
NASA Technical Reports Server (NTRS)
Gupta, K. K.
1973-01-01
A wide range of eigenvalue problems encountered in practical structural engineering analyses is defined, in which the structures are assumed to be discretized by any suitable technique such as the finite-element method. A review of the usual numerical procedures for the solution of such eigenvalue problems is presented and is followed by an extensive account of recently developed eigenproblem solution procedures. Particular emphasis is placed on the new numerical algorithms and associated computer programs based on the Sturm sequence method. Eigenvalue algorithms developed for efficient solution of natural frequency and buckling problems of structures are presented, as well as some eigenvalue procedures formulated in connection with the solution of quadratic matrix equations associated with free vibration analysis of structures. A new algorithm is described for natural frequency analysis of damped structural systems.
Numerical study of water flow in a system of two basins connected by a channel with periodic forcing
NASA Astrophysics Data System (ADS)
Lopez Sanchez, Erick Javier; Ruiz Chavarria, Gerardo
2010-11-01
In oceanography the transport of particles is a frecuent phenomenon, for instance ocean currents carry the plankton from one place to another. In shallow waters drag and depositation of sand can affect positively or negatively certain human activities, such as the navigation near the coast; on the other hand, sand banks can help to mitigate the force with which a tsunami approaches a populated coastline. We study the flow of water in a system of two basins connected by a channel, generated by a periodic forcing that simulates the tidal force. The simulation is done by solving the system of equations in stream function (ψ ) - vorticity (φ ) formulation, obtained from the Navier-Stokes and continuity in two dimensions. A pseudo-spectral method based on polynomials Chebyshev is used. The tidal forcing is reflected in the fact that Reynolds number becomes time dependent. We obtained results that are consistent with previous works (like: Wells, M. G. and Van Heijst, G.J.F., Dynamics of Atmospheres and Oceans, 37 (2003) 223-244). For example the formation and displacement of a dipole at the exit of the channel is observed. The velocity field obtained numerically is used to study the transport of particles by the flow, where the dipole moves away from the channel output or return to it, depending on the geometry of the system and period occurrence of the phenomenon.
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).
BSAS: A basic program for two-dimensional subsidence analysis in sedimentary basins
NASA Astrophysics Data System (ADS)
Jin, Jiuqiang
1994-11-01
Subsidence analysis, including geohistory analysis and backstripping, now is a usual approach in basin analysis to investigate quantitatively the basin formation and evolution. Its results are used widely in basin simulation as framework for other reconstructions such as stratigraphic and thermal modeling. These analyses may have been restricted to individual wells from which the necessary data are available. This restriction limits the two- and three-dimensional basin analysis and modeling. A BASIC computer program is presented for handling this problem. The program, BSAS, uses a key well as a control point to obtain the basic data for subsidence analysis, and extrapolates the data set to a cross section throughout the entire basin. In this way, geohistory analysis and backstripping can be carried out at any site along the section in order to generate the corresponding tectonic and total subsidence curves. Furthermore, the two-dimensional tectonic and total subsidence profiles for selected geological time slices can be plotted.
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.
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.
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.
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.
1-D Numerical Analysis of ABCC Engine Performance
NASA Technical Reports Server (NTRS)
Holden, Richard
1999-01-01
ABCC engine combines air breathing and rocket engine into a single engine to increase the specific impulse over an entire flight trajectory. Except for the heat source, the basic operation of the ABCC is similar to the basic operation of the RBCC engine. The ABCC is intended to have a higher specific impulse than the RBCC for single stage Earth to orbit vehicle. Computational fluid dynamics (CFD) is a useful tool for the analysis of complex transport processes in various components in ABCC propulsion system. The objective of the present research was to develop a transient 1-D numerical model using conservation of mass, linear momentum, and energy equations that could be used to predict flow behavior throughout a generic ABCC engine following a flight path. At specific points during the development of the 1-D numerical model a myriad of tests were performed to prove the program produced consistent, realistic numbers that follow compressible flow theory for various inlet conditions.
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.
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…
NASA Astrophysics Data System (ADS)
Yang, Jianwen; Bull, Stuart; Large, Ross
2004-10-01
This paper presents the first hydrogeological model that fully couples transient fluid flow, heat and solute transport associated with the formation of the HYC SEDEX deposit in the McArthur Basin, northern Australia. Numerical results reveal that salinity plays an important role in controlling hydrothermal fluid migration. In particular, it appears that it is the distribution of evaporitic units within a given basin, rather than their absolute abundance, that controls the development of free convection. Relatively saline conditions at the seafloor strengthen the thermally-induced buoyancy force and hence promote free convection of basinal solutions; whereas high salinities at the bottom counteract the thermal function of natural geothermal gradient and suppress the development of convective hydrothermal fluid circulation. In the latter case, higher thermal gradients are required to initiate substantial free convective fluid flow. Numerical experiments also suggest the position of an ore body with respect to its vent system may be controlled by the spatial and temporal salinity distributions in the basin. Vent-distal ore formation, a result of exhalation of brines that are denser than seawater and hence can flow away from the vent region, is promoted by moderate salinity at the seafloor and higher salinity in the aquifer. Vent-proximal ore accumulation, a result of pluming upon exhalation of brines less dense than seawater, is favored by the highest salinity conditions occurring near the level of the seafloor.
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
Enhancement of the robustness on dynamic speckle laser numerical analysis
NASA Astrophysics Data System (ADS)
Cardoso, R. R.; Braga, R. A.
2014-12-01
When a dynamic process occurs in a material under laser illumination the phenomenon that appears is named dynamic laser speckle, or biospeckle laser (BSL) if we have a biological material. The work with biological material and its dispersion of light brings considerable complexity, and the way we can deal with that complex outputs is based on a sophisticated analysis of the images associated to statistical approaches. One of the most known numerical analysis of the BSL has been applied in many applications, and it is named Inertia Moment, however its outputs have great coefficients of variation, most of the time attributed to the variability of the biological material. A change in the inertia moment method was done and the Absolute Value of the Differences (AVD) was presented as an alternative to reduce the variations and to follow a broader range of frequencies than before. However, it was not enough concerning with the variability of the outputs. This study aimed to improve the BSL technique in order to enhance the robustness of the numerical method known as Inertia Moment (IM) and improve the absolute value of the differences reducing even more its coefficient of variation by means of changes in the normalization provided in both methods. The new normalization was tested in simulated data, as well as in real data. The results showed the improvements of the methods, IM and AVD, with the reduction of the coefficients of variation of the activity in the outputs, increasing the robustness of the analysis.
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.
Hybridizing experimental, numerical, and analytical stress analysis techniques
NASA Astrophysics Data System (ADS)
Rowlands, Robert E.
2001-06-01
Good measurements enjoy the advantage of conveying what actually occurs. However, recognizing that vast amounts of displacement, strain and/or stress-related information can now be recorded at high resolution, effective and reliable means of processing the data become important. It can therefore be advantageous to combine measured result with analytical and computations methods. This presentation will describe such synergism and applications to engineering problems. This includes static and transient analysis, notched and perforated composites, and fracture of composites and fiber-filled cement. Experimental methods of moire, thermo elasticity and strain gages are emphasized. Numerical techniques utilized include pseudo finite-element and boundary-element concepts.
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.
Diffraction patterns from multiple tilted laser apertures: numerical analysis
NASA Astrophysics Data System (ADS)
Kovalev, Anton V.; Polyakov, Vadim M.
2016-03-01
We propose a Rayleigh-Sommerfeld based method for numerical calculation of multiple tilted apertures near and far field diffraction patterns. Method is based on iterative procedure of fast Fourier transform based circular convolution of the initial field complex amplitudes distribution and impulse response function modified in order to account aperture and observation planes mutual tilt. The method is computationally efficient and has good accordance with the results of experimental diffraction patterns and can be applied for analysis of spatial noises occurring in master oscillator power amplifier laser systems. The example of diffraction simulation for a Phobos-Ground laser rangefinder amplifier is demonstrated.
A Preliminary Analysis of Disturbance Tracksover the Mediterranean Basin
NASA Astrophysics Data System (ADS)
Karas, S.; Zangvil, A.
The Mediterranean basin experiences considerable cyclone activity mostly during fall, winter and spring and diminished activity during summer. In this study we present results of synoptic disturbance track analysis for two contrasting winter months and two, near average, summer months over the eastern Mediterranean. The surface and 500hPa disturbance tracks were subjectively analyzed from two points of view. First, looking at tracks of conventionally defined cyclone centers (eddies) based on actual pressure and height distribution and second, looking at tracks of transient cyclonic disturbances (TRADs), defined as centers of negative deviations from the time mean. The second type of analysis demonstrated a considerable increase in the number of detectable tracks. Over the Mediterranean and vicinity the ratio between the number of surface TRAD tracks to cyclone tracks is, about 2, whereas at 500hPa the ratio is much higher, about 5. However, the average life span of transient disturbances was only slightly longer than that of conventional cyclones (mainly at 500hPa). At the surface and at 500hPa about 50% of the cyclone tracks coincided to a certain extent with TRAD tracks. In summer, when conventional analysis over the eastern Mediterranean yields mostly quasi-stationary low pressure centers associated with the Persian Gulf Trough, we detected clear signs of transient disturbances. Some interpretations of the differences between cyclones and TRADs in terms of weather in the eastern Mediterranean are also made.
The Lake Tahoe Basin: A systems analysis of its characteristics and human carrying capacity
NASA Astrophysics Data System (ADS)
Gilliland, Martha W.; Clark, B. David
1981-09-01
A systems analysis of the Lake Tahoe Basin indicates significant and accelerating environmental deterioration within the basin, suggests that Tahoe is poised for yet another round of urban expansion, delineates the portion of Tahoe's resources that are consumed by gaming recreation vis-à-vis outdoor recreation, and identifies the Federal government as a contributor to Tahoe's problems. In response to the need for a holistic approach to basin-wide planning and management, ecological carrying capacity concepts are explored as they may be applicable to the Basin's growth patterns, and ideas on establishing a carrying capacity for Tahoe are developed.
NASA Astrophysics Data System (ADS)
Magesh, N. S.; Jitheshlal, K. V.; Chandrasekar, N.; Jini, K. V.
2013-06-01
A morphometric analysis of Bharathapuzha river basin has been carried out using geoprocessing techniques in GIS. This technique is found relevant for the extraction of river basin and its drainage networks. The extracted drainage network was classified according to Strahler's system of classification and it reveals that the terrain exhibits dendritic to sub-dendritic drainage pattern. The Bharathapuzha drainage basin is sprawled over an area of 5,988.56 km2. The study area was designated as seventh-order basin and lower order streams mostly dominate the basin with the drainage density value of 1.07 km/km2. The slope of basin varied from 0° to 70° and the slope variation is chiefly controlled by the local geology and erosion cycles. The elongation ratio of the basin is 0.57 indicating that the study area is elongated with moderate relief and steep slopes. The drainage texture of the basin is 7.78 which indicates an intermediate texture that exists over the region. Hence, from the study, it can be concluded that remote sensing data (SRTM-DEM) coupled with geoprocessing techniques prove to be a competent tool in morphometric analysis and the data can be used for basin management and other hydrological studies in future.
Brisbin, S.A.
1996-03-06
This document delineates the plan for preparation, review, and approval of the Packaging Design Crieteria for the K Basin Sludge Transportation System and the Associated on-site Safety Analysis Report for Packaging. The transportation system addressed in the subject documents will be used to transport sludge from the K Basins using bulk packaging.
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.
Asymptotic and numerical analysis of electrohydrodynamic flows of dielectric liquid
NASA Astrophysics Data System (ADS)
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.
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.
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).
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.
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
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.
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.
NASA Astrophysics Data System (ADS)
Anka, Z.; Rodrigues, E.; Ostanin, I.; di Primio, R.; Stoddart, D.; Horsfield, B.
2012-04-01
The Hammerfest Basin, located in the SW Barents Sea, is characterized by present-day under-filled hydrocarbon accumulations, which are known to have leaked in the past (Dimakis, 1998; Ohm et al. 2008). Late Cenozoic erosion and high latitude glaciations are thought to have driven the redistribution and leakage of these thermogenic fluids providing a source of thermogenic methane to the hydrosphere. The timing, extent and driving factors for the leakage events are still largely unconstrained. Therefore, we investigated present and past leakage of liquid and gaseous hydrocarbons over the Snøhvit and Albatross gas fields of the Hammerfest Basin and analyse its dynamics in response to multiple phases of tectonic uplift and glaciations by means of a combined approach of numerical modelling and interpretation of a high resolution 3D seismic reflection cube. Our data-constrained 3D basin model of the basin allowed us to quantify the masses of hydrocarbons generated, accumulated and eventually leaked from the reservoirs during the evolution of the basin. Particular emphasis was placed on analysing the fate of leaked volumes of methane within the dynamics of Plio-Quaternary glacial cycles and possible formation or destabilization of gas hydrate deposits. Besides reproducing quite accurately the composition and volume of the hydrocarbons -particularly the gaseous phase- present in the main reservoirs, the model predicts the development of overpressures in the reservoirs due to the ice loading of the basin during the glacial periods. Predicted reservoir pressure fluctuations derived from cyclic loading-unloading during the glacial-interglacial periods are up to 5 MPa. The under-filled nature of the present-day accumulations would result from leakage events during the episodes of glacial retreat, in the transition from glacial to interglacial periods. Considerations of the gas hydrate stability conditions in the basin during the time span between 1.00Ma and ≈11,500 years
NASA Astrophysics Data System (ADS)
Jones, A. P.
2000-09-01
Understanding basin-wide sediment dynamics, both spatially and temporally, is an important antecedent to eventual quantitative interpretation of sediment transfer within mountain fluvial systems. This paper describes an attempt to trace sediment transfer modes and pathways using clast lithological analysis in a small mountain basin strongly influenced by glaciation: the Pineta Basin in the central Pyrenees of Spain. The paper interprets slope-channel interaction by encompassing the whole basin, enabling staged sedimentary pathways to be revealed. Additionally, bed-material textures of the modern rivers and youngest La Sarra Terrace were investigated to provide further information on the geomorphic coupling of the system. Relatively few studies have taken this approach. Glacial and later, fluvial systems transferred the sediments creating laterally extensive, polylithological sediment stores. Local depositional systems overprint this inherited signature. To what extent depends on the size and energy of the local system. Significant impacts are made by conduits, such as large-scale fluvially dominated fans and waterfalls, which deliver local lithologies to the main river. Conduits may be part of the main river system or part of the tributary system. Conduits are the most important elements when considering provenance studies and theoretical modelling.
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
Anderson, M.; Matti, J.; Jachens, R.
2004-01-01
The San Bernardino basin is an area of Quaternary extension between the San Jacinto and San Andreas Fault zones in southern California. New gravity data are combined with aeromagnetic data to produce two- and three-dimensional models of the basin floor. These models are used to identify specific faults that have normal displacements. In addition, aeromagnetic maps of the basin constrain strike-slip offset on many faults. Relocated seismicity, focal mechanisms, and a seismic reflection profile for the basin area support interpretations of the gravity and magnetic anomalies. The shape of the basin revealed by our interpretations is different from past interpretations, broadening its areal extent while confining the deepest parts to an area along the modern San Jacinto fault, west of the city of San Bernardino. Through these geophysical observations and related geologic information, we propose a model for the development of the basin. The San Jacinto fault-related strike-slip displacements started on fault strands in the basin having a stepping geometry thus forming a pull-apart graben, and finally cut through the graben in a simpler, bending geometry. In this model, the San Bernardino strand of the San Andreas Fault has little influence on the formation of the basin. The deep, central part of the basin resembles classic pull-apart structures and our model describes a high level of detail for this structure that can be compared to other pull-apart structures as well as analog and numerical models in order to better understand timing and kinematics of pull-apart basin formation. Copyright 2004 by the American Geophysical Union.
Analysis of Oblique Wedges Using Analog and Numerical Models
NASA Astrophysics Data System (ADS)
Haq, S. S.; Koster, K.; Martin, R. S.; Flesch, L. M.
2010-12-01
Oblique plate motion is understood to be a primary factor in determining the style and location of deformation at many convergent margins. These margins are frequently characterized by a dominant strike-slip fault parallel to the margin, which accommodates margin-parallel motion and shear and is adjacent to partitioned and near margin-normal thrusting. We have performed a series of analog experiment in which we have simulated oblique wedges with frictional and layered, friction over viscous, rheologies. Using the detailed analysis of topography and strain from these analog models we have compared them to geometrically similar 2D and 3D numerical models. While our pure frictional analog wedges are characterized by numerous discrete thrust faults in the pro-wedge and a zone of shear between the pro-wedge and the retro-wedges, our layered wedges have a dominate shear zone that is long-lived. In all models the highest rate of contractional deformation is at the thrust front, while the highest rate of shear is isolated in a relatively narrow zone at the back of the pro-wedge. Because the layered analog wedge is better able isolate shear behind the pro-wedge it can better partition strain into dip-slip thrusting normal to the margin. Our numerical simulations support the assertion that a relatively small amount of extensional stress is needed to play a significant role in the structural evolution of convergent systems. However, the manner in which this stress is localized on discrete structures, and in particular, how the style of strain (extension or contraction) will evolve, is a strong function of rheology and its strength at depth for a given initial geometry.
Stochastic algorithms for the analysis of numerical flame simulations
Bell, John B.; Day, Marcus S.; Grcar, Joseph F.; Lijewski, Michael J.
2001-12-14
Recent progress in simulation methodologies and new, high-performance parallel architectures have made it is possible to perform detailed simulations of multidimensional combustion phenomena using comprehensive kinetics mechanisms. However, as simulation complexity increases, it becomes increasingly difficult to extract detailed quantitative information about the flame from the numerical solution, particularly regarding the details of chemical processes. In this paper we present a new diagnostic tool for analysis of numerical simulations of combustion phenomena. Our approach is based on recasting an Eulerian flow solution in a Lagrangian frame. Unlike a conventional Lagrangian viewpoint in which we follow 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 that is transported through the domain by advection and diffusion. Reactions ca use the atom to shift from one species to another with the subsequent transport given by the movement of the new species. We represent these processes using a stochastic particle formulation that treats advection deterministically and models diffusion as a suitable random-walk process. Within this probabilistic framework, reactions can be viewed as a Markov process transforming molecule to molecule with given probabilities. In this paper, we discuss the numerical issues in more detail and demonstrate that an ensemble of stochastic trajectories can accurately capture key features of the continuum solution. We also illustrate how the method can be applied to studying the role of cyanochemistry on NOx production in a diffusion flame.
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
Numerical analysis of the V-Y shaped advancement flap.
Remache, D; Chambert, J; Pauchot, J; Jacquet, E
2015-10-01
The V-Y advancement flap is a usual technique for the closure of skin defects. A triangular flap is incised adjacent to a skin defect of rectangular shape. As the flap is advanced to close the initial defect, two smaller defects in the shape of a parallelogram are formed with respect to a reflection symmetry. The height of the defects depends on the apex angle of the flap and the closure efforts are related to the defects height. Andrades et al. 2005 have performed a geometrical analysis of the V-Y flap technique in order to reach a compromise between the flap size and the defects width. However, the geometrical approach does not consider the mechanical properties of the skin. The present analysis based on the finite element method is proposed as a complement to the geometrical one. This analysis aims to highlight the major role of the skin elasticity for a full analysis of the V-Y advancement flap. Furthermore, the study of this technique shows that closing at the flap apex seems mechanically the most interesting step. Thus different strategies of defect closure at the flap apex stemming from surgeon's know-how have been tested by numerical simulations. PMID:26342442
Schreffler, Curtis L.
1996-01-01
A water-use analysis computer program was developed for the Neshaminy Creek Basin to assist in managing and allocating water resources in the basin. The program was developed for IBM-compatible personal computers. Basin analysis and the methodologies developed for the Neshaminy Creek Basin can be transferred to other watersheds. The development and structure of the water-use analysis program is documented in this report. The report also serves as a user's guide. The program uses common relational database-management software that allows for water use-data input, editing, updating and output and can be used to generate a watershed water-use analysis report. The watershed-analysis report lists summations of public-supply well withdrawals; a combination of industrial, commercial, institutional, and ground-water irrigation well withdrawals; spray irrigation systems; a combination of public, industrial, and private surface-water withdrawals; wastewater-tratement-facility dishcarges; estimates of aggregate domestic ground-water withdrawals on an areal basin or subbasin basis; imports and exports of wastewater across basin or subbasin divides; imports and exports of public water supplies across basin or subbasin divides; estimates of evaporative loss and consumptive loss from produce incorporation; industrial septic-system discharges to ground water; and ground-water well-permit allocations.
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.
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
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.
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
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.
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.
Numerical analysis of the dynamics of distributed vortex configurations
NASA Astrophysics Data System (ADS)
Govorukhin, V. N.
2016-08-01
A numerical algorithm is proposed for analyzing the dynamics of distributed plane vortex configurations in an inviscid incompressible fluid. At every time step, the algorithm involves the computation of unsteady vortex flows, an analysis of the configuration structure with the help of heuristic criteria, the visualization of the distribution of marked particles and vorticity, the construction of streamlines of fluid particles, and the computation of the field of local Lyapunov exponents. The inviscid incompressible fluid dynamic equations are solved by applying a meshless vortex method. The algorithm is used to investigate the interaction of two and three identical distributed vortices with various initial positions in the flow region with and without the Coriolis force.
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.
Asymptotic analysis of numerical wave propagation in finite difference equations
NASA Technical Reports Server (NTRS)
Giles, M.; Thompkins, W. T., Jr.
1983-01-01
An asymptotic technique is developed for analyzing the propagation and dissipation of wave-like solutions to finite difference equations. It is shown that for each fixed complex frequency there are usually several wave solutions with different wavenumbers and the slowly varying amplitude of each satisfies an asymptotic amplitude equation which includes the effects of smoothly varying coefficients in the finite difference equations. The local group velocity appears in this equation as the velocity of convection of the amplitude. Asymptotic boundary conditions coupling the amplitudes of the different wave solutions are also derived. A wavepacket theory is developed which predicts the motion, and interaction at boundaries, of wavepackets, wave-like disturbances of finite length. Comparison with numerical experiments demonstrates the success and limitations of the theory. Finally an asymptotic global stability analysis is developed.
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.
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.
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)
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
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
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.
Numerical analysis of field-scale transport of bromacil
NASA Astrophysics Data System (ADS)
Russo, David; Tauber-Yasur, Inbar; Laufer, Asher; Yaron, Bruno
Field-scale transport of bromacil (5-bromo-3- sec-butyl-6-methyluracil) was analyzed using two different model processes for local description of the transport. The first was the classical, one-region convection dispersion equation (CDE) model while the second was the two-region, mobile-immobile (MIM) model. The analyses were performed by means of detailed three-dimensional, numerical simulations of the flow and the transport [Russo, D., Zaidel, J. and Laufer, A., Numerical analysis of flow and transport in a three-dimensional partially saturated heterogeneous soil. Water Resour. Res., 1998, in press], employing local soil hydraulic properties parameters from field measurements and local adsorption/desorption coefficients and the first-order degradation rate coefficient from laboratory measurements. Results of the analyses suggest that for a given flow regime, mass exchange between the mobile and the immobile regions retards the bromacil degradation, considerably affects the distribution of the bromacil resident concentration, c, at relatively large travel times, slightly affects the spatial moments of the distribution of c, and increases the skewing of the bromacil breakthrough and the uncertainty in its prediction, compared with the case in which the soil contained only a single (mobile) region. Mean and standard deviation of the simulated concentration profiles at various elapsed times were compared with measurements from a field-scale transport experiment [Tauber-Yasur, I., Hadas, A., Russo, D. and Yaron, B., Leaching of terbuthylazine and bromacil through field soils. Water, Air Soil Poln., 1998, in press] conducted at the Bet Dagan site. Given the limitations of the present study (e.g. the lack of detailed field data on the spatial variability of the soil chemical properties) the main conclusion of the present study is that the field-scale transport of bromacil at the Bet Dagan site is better quantified with the MIM model than the CDE model.
ERIC Educational Resources Information Center
Henle, James M.
This pamphlet consists of 17 brief chapters, each containing a discussion of a numeration system and a set of problems on the use of that system. The numeration systems used include Egyptian fractions, ordinary continued fractions and variants of that method, and systems using positive and negative bases. The book is informal and addressed to…
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
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.
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.
NASA Astrophysics Data System (ADS)
Kavetski, Dmitri; Clark, Martyn P.
2010-10-01
Despite the widespread use of conceptual hydrological models in environmental research and operations, they remain frequently implemented using numerically unreliable methods. This paper considers the impact of the time stepping scheme on model analysis (sensitivity analysis, parameter optimization, and Markov chain Monte Carlo-based uncertainty estimation) and prediction. It builds on the companion paper (Clark and Kavetski, 2010), which focused on numerical accuracy, fidelity, and computational efficiency. Empirical and theoretical analysis of eight distinct time stepping schemes for six different hydrological models in 13 diverse basins demonstrates several critical conclusions. (1) Unreliable time stepping schemes, in particular, fixed-step explicit methods, suffer from troublesome numerical artifacts that severely deform the objective function of the model. These deformations are not rare isolated instances but can arise in any model structure, in any catchment, and under common hydroclimatic conditions. (2) Sensitivity analysis can be severely contaminated by numerical errors, often to the extent that it becomes dominated by the sensitivity of truncation errors rather than the model equations. (3) Robust time stepping schemes generally produce "better behaved" objective functions, free of spurious local optima, and with sufficient numerical continuity to permit parameter optimization using efficient quasi Newton methods. When implemented within a multistart framework, modern Newton-type optimizers are robust even when started far from the optima and provide valuable diagnostic insights not directly available from evolutionary global optimizers. (4) Unreliable time stepping schemes lead to inconsistent and biased inferences of the model parameters and internal states. (5) Even when interactions between hydrological parameters and numerical errors provide "the right result for the wrong reason" and the calibrated model performance appears adequate, unreliable
Mukhopadhyay, Sumit; Spycher, Nicolas; Pester, Nick; Saldi, Giuseppe; Beyer, John; Houseworth, Jim; Knauss, Kevin
2014-09-04
This report presents findings for hydrological and chemical characteristics and processes relevant to large-scale geologic CO_{2} sequestration in the Newark Basin of southern New York and northern New Jersey. This work has been conducted in collaboration with the Tri-Carb Consortium for Carbon Sequestration — comprising Sandia Technologies, LLC; Conrad Geoscience; and Schlumberger Carbon Services.
A Structural Analysis of the Lewiston Basin, Clarkston, WA
NASA Astrophysics Data System (ADS)
Alloway, M.; Watkinson, A.; Reidel, S. P.
2010-12-01
The Lewiston Structure is located in southeastern Washington / west-central Idaho and is a generally E-W trending asymmetric, non-cylindrical anticline in the Columbia River Basalt Group (CRBG) that transfers displacement into the Limekiln fault system to the southeast. A serial cross-section analysis and 3-D construction of this structure shows how the fold varies along its trend and sheds light on the deformational history of the Lewiston Basin. Construction of the fold’s 3-D form shows that the fold’s wavelength increases and amplitude decreases eastward along its trend. Balanced cross-sections show approximately 5% shortening across the structure which is consistent with the Yakima Fold Belt (YFB). Although the structure is similar to the YFB, it does not form part of a belt and its local nature has been suggested to mark the cratonic boundary of the Cretaceous. Discovery of an angular unconformity in the Grande Ronde Basalt - reverse polarity unit 1 (GRB-R1) proves that the NE trending section of the fold was deforming during emplacement of R1 and allows separation of the fold into two structural domains. Analysis of the two domains using the Gauss method for heterogeneous fault-slip data indicate NW-SE shortening during R1 time and N-S shortening for post CRBG emplacement. Furthermore, slip data for strain-inversion and specification of spatial-distribution patterns help identify the existence of a transpressional tectonic environment. The nature of faulting associated with the Lewiston Structure is a topic of some debate, namely the presence of a reverse fault on the southern limb of the fold conspicuously hidden by the Snake River. The reverse fault under debate outcrops to the east of the field area and is GRB-R2 (reverse polarity unit 2) thrust over Pliocene gravels. Better control on unit thicknesses and map contacts rule out the possibility of a reverse fault exposed on the surface of the southern limb of the fold in the field area. This major fault
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
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.
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 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.
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 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.
Numerical Analysis of Orbital Perturbation Effects on Inclined Geosynchronous SAR.
Dong, Xichao; Hu, Cheng; Long, Teng; Li, Yuanhao
2016-09-02
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.
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.
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
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).
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...
Trace fossil analysis of lacustrine facies and basins
Buatois, L.A.; Mangano, M.G.
1998-01-01
Two ichnofacies are typical of lacustrine depositional systems. The Scoyenia ichnofacies characterizes transitional terrestrial/nonmarine aquatic substrates, periodically inundated or desiccated, and therefore is commonly present in lake margin facies. The Mermia ichnofacies is associated with well oxygenated, permanent subaqueous, fine-grained substrates of hydrologically open, perennial lakes. Bathymetric zonations within the Mermia ichnofacies are complicated by the wide variability of lacustrine systems. Detected proximal-distal trends are useful within particular lake basins, but commonly difficult to extrapolate to other lakes. Other potential ichnofacies include the typically marine Skolithos ichnofacies for high-energy zones of lakes and substrate-controlled, still unnamed ichnofacies, associated to lake margin deposits. Trace fossils are useful for sedimentologic analysis of event beds. Lacustrine turbidites are characterized by low-diversity suites, reflecting colonization by opportunistic organisms after the turbidite event. Underflow current beds record animal activity contemporaneous with nearly continuous sedimentation. Ichnologic studies may also help to distinguish between marine and lacustrine turbidites. Deep-marine turbidites host the Nereites ichnofacies that consists of high diversity of ornate grazing traces and graphoglyptids, recording highly specialized feeding strategies developed to solve the problem of the scarcity of food in the deep sea. Deep lacustrine environments contain the Mermia ichnofacies, which is dominated by unspecialized grazing and feeding traces probably related to the abundance and accessibility of food in lacustrine systems. The lower diversity of lacustrine ichnofaunas in comparison with deep-sea assemblages more likely reflects lower species diversity as a consequence of less stable conditions. Increase of depth and extent of bioturbation through geologic time produced a clear signature in the ichnofabric record of
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).
Miller, B.M. )
1990-05-01
Most of the world's energy resources and many of its metallic and mineral resources are derived from complex sources in sedimentary basins. A comprehensive basin analysis requires an understanding of data from many specialties, including sedimentology, stratigraphy geophysics, structural geology, and geochemistry. Such an integrated analysis is almost impossible without a computer. Research efforts in the US Geological Survey are currently being directed at exploring the feasibility of applying expert systems and knowledge acquisition techniques to the design and development of a global system of classification and geological analysis of sedimentary basins to assess their petroleum potential. The primary objective is the design of a prototype object-oriented expert system interfaced with a geographic information system (GIS) that captures both the logic used to define the geologic concepts and the reasoning under uncertainty that enables geologists to understand and reconstruct the geologic history of a sedimentary basin. NEXPERT OBJECT, a hybrid expert system that has the ability to support both a reasoning system and an object-oriented representation, is currently being used as the design tool to provide high-level, expert-oriented features to create, edit, and build knowledge bases for the basin analysis program. This system provides these capabilities through documentation of major basin analysis components such as stratigraphy, structural geology, and sedimentology. It is designed to analyze the traditional concepts of source, reservoir, and trapping mechanism; to help in the diagnosis of geological conditions favorable for the occurrence of petroleum or other energy resources; and to assist in the assessment of these resources. The design and content of the expert system program is discussed for application to basin analysis studies.
Analysis of coaxial spray combustion flames and related numerical issues
NASA Technical Reports Server (NTRS)
Liang, P. Y.
1986-01-01
An approach to the simulation of strongly coupled multiphase flows in combustion hardware is sketched and its unique requirements highlighted. An example of a successful application to a coaxial injector flame is presented. Furthermore, several numerical issues that tend to interact with the physics of the problem are discussed with special regard to their potential impact on the choices of numerical parameters by the analyst. These include the issues of stability, numerical diffusivity, stiffness, and boundary conditions. The theme of this paper focuses on the intriguing relationships among the grid, the solution algorithm, and the actual physical mechanisms themselves.
Heilweil, V.M.; Freethey, G.W.; Wilkowske, C.D.; Stolp, B.J.; Wilberg, D.E.
2000-01-01
Because rapid growth of communities in Washington and Iron Counties, Utah, is expected to cause an increase in the future demand for water resources, a hydrologic investigation was done to better understand ground-water resources within the central Virgin River basin. This study focused on two of the principal ground-water reservoirs within the basin: the upper Ash Creek basin ground-water system and the Navajo and Kayenta aquifer system. The ground-water system of the upper Ash Creek drainage basin consists of three aquifers: the uppermost Quaternary basin-fill aquifer, the Tertiary alluvial-fan aquifer, and the Tertiary Pine Valley monzonite aquifer. These aquifers are naturally bounded by the Hurricane Fault and by drainage divides. On the basis of measurements, estimates, and numerical simulations of reasonable values for all inflow and outflow components, total water moving through the upper Ash Creek drainage basin ground-water system is estimated to be about 14,000 acre-feet per year. Recharge to the upper Ash Creek drainage basin ground-water system is mostly from infiltration of precipitation and seepage from ephemeral and perennial streams. The primary source of discharge is assumed to be evapotranspiration; however, subsurface discharge near Ash Creek Reservoir also may be important. The character of two of the hydrologic boundaries of the upper Ash Creek drainage basin ground-water system is speculative. The eastern boundary provided by the Hurricane Fault is assumed to be a no-flow boundary, and a substantial part of the ground-water discharge from the system is assumed to be subsurface outflow beneath Ash Creek Reservoir along the southern boundary. However, these assumptions might be incorrect because alternative numerical simulations that used different boundary conditions also proved to be feasible. The hydrogeologic character of the aquifers is uncertain because of limited data. Difference in well yield indicate that there is considerable
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)
Oblique opening of Skyros Basin in the North Aegean Sea, based on Morphotectonic Analysis
NASA Astrophysics Data System (ADS)
Papanikolaou, Dimitris; Nomikou, Paraskevi; Livanos, Isidoros; Papantoniou, George; Rousakis, Grigoris; Lampridou, Danai
2015-04-01
Detailed analysis of swath bathymetry and seismic reflection profiling has revealed the morphotectonic structure of the Skyros Basin in North Aegean Sea (Greece). The overall geometry of the basin is shaped by a major slope discontinuity, separating the continental platform from the continental slope at depths between 200-400m. The basin forms an equilateral triangle. Its base is 50km long NW-SE trending at the southwest, parallel to the Skyros Island, whereas its pic is located at the northeast, north of Lesvos Island. The basin comprises 9 sub-basins at depths varying from 1200m at the southwest to 600m to the northeast and is structurally divided into three parts: i) the eastern part forms a longitudinal semi-graben with one sub-basin trending ENE-WSW of 45km length, but only 5-8 Km width at depths varing between 600-700m. This sub-basin is bounded to the south by a marginal fault of >1.5km throw but with unknown horizontal displacement. ii) the central part that forms the predominant part of the triangle with 45 Km long NW-SE trending base and 70km long axis at the NE-SW direction. The central part corresponds to an assymetric graben with a 70km long major marginal fault with >1500m throw along its southern slopes and a 70 km long antithetic fault with >400m throw along its northern slopes. It comprises 5 sub-basins with depths ranging between 950-700m, bounded by important E-W trending strike slip fault zones, characterized by flower structures, with minor vertical components ranging from a few meters up to 200m. iii) the western part of the basin trends NW-SE, is 55 Km long and 25 Km wide, revealing a NW-SE tectonic graben. It comprises two sub-basins, oriented NW-SE separated by an intermediate transverse fault zone. The throw of the western marginal faults offshore Skyros Island exceeds 1200m, whereas the throw of the parallel faults creating the NW-SE tectonic graben is limited to a few hundreds meters. It should be emphasized that the Alpine basement was
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
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.
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.
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.
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.
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
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.
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.
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.
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
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.
NASA Astrophysics Data System (ADS)
Baristeas, N.; Anka, Z.; di Primio, R.; Rodriguez, J. F.; Marchal, D.; Dominguez, F.
2012-04-01
A detailed tectono-stratigraphic analysis of the Malvinas Basin development, located offshore the Argentinean margin, was carried out. This was achieved through the interpretation of around 65,000 km of 2D seismic reflection profiles, spanning a dense grid on the shelf and the upper-slope of the basin. Five main seismo-stratigraphic units and their sub-units, informally named U1 to U5 a/b, bound by major unconformities were identified and correlated with the Mesozoic to Cenozoic main tectonic phases of the basin. U1 (Pre-168 Ma) represents the seismic basement and deepens gradually southwards. U2 (168-150.5 Ma, syn rift phase) fills regional depressions, onlapping the basement, and it thickens and deepens southwards. U1 and U2 are affected by several syn-rift normal faults, which have a main NE-SW strike direction in the south of the basin and a NW-SE strike direction in the centre of the basin. This suggests that the Malvinas Basin may have been developed initially as a rift basin with two different extensional directions. (1) a NW-SE directed extension probably linked with the opening of the Weddell Sea (Early Mid-Jurassic) and (2) a NE-SW directed extension most likely linked with the opening of the South Atlantic during Mid-Jurassic to Early Cretaceous. U3 (150.5-68 Ma, sag phase) is mainly an aggradational wedge-shaped unit. Some syn-rift faults continue into the Cretaceous. Sedimentation in this unit is mainly derived from the north and during Mid-Cretaceous also from the northeast, as documented by the presence of a southwestward prograding sedimentary fan located in the northeast of the basin. U4 (68-42.5 Ma, transtensional foredeep phase) overlies unconformly U3 and thickens to the south. Sediment input decreases dramatically during that time and only a thin sedimentary succession was deposited over the entire basin. Although a regional compressional regime is established from late Cretaceous to Cenozoic due to the Andean orogenesis, an extensional regime
Microstructure analysis of marine seismogenic turbidites in Kumano forearc basin
NASA Astrophysics Data System (ADS)
Okutsu, N.; Ashi, J.; Omura, A.; Yamaguchi, A.; Suganuma, Y.; Murayama, M.
2015-12-01
An elongated depression was located in an ENE-WSW direction between the southern margin of the forearc basin and the outer ridge off Kumano. A terminal basin that captures all sediments supplied from outside is developed within this depression, making it an adequate site to study paleoseismology using seismogenic turbidites. Previous study results reveal the Cs-137 and Pb-210 that the upper 17-cm mud layer was deposited immediately after the 2004 off Kii Peninsula earthquakes (Ashi et al., 2015, JpGU Meeting abstract). We herein investigate the characteristics of marine seismogenic turbidites based on various measurements including their compositions, X-ray CT images, and anisotropy of magnetic susceptibility (AMS). We observed a very thin fine-grained sand layer of 6 mm thick at 17 cm below seafloor and a volcanic ash layer of 15 cm thick at 5.1 m. The X-ray CT image shows seven silty clay laminations thinning upwards at 6 -15 cm below seafloor with homogeneous clay based silt above it, and several foraminifera-enriched layer below 1.7 m. The AMS parameters decrease upwards in the interval showing parallel/cross laminations and the lowest value is measured in the overlying silt layer. Moreover, the paleocurrent directions showed the NW-SE flow direction. These results indicate that the upper 17 cm layer beginning from the very fine-grained sand can be interpreted to be formed by a low density reflected gravity flow between the SE and NW dipping slopes of the basin. Structural observations by X-ray CT scanner reveal characteristic structures yielding various orientation oblique to bedding plane at the mud layer 17 cm below seafloor, suggesting that the structure is likely formed by coseismic deformation accompanied by the earthquake in 2004 or earlier ones. Magnetic fabrics derived from AMS measurements and the structure observed by X-ray CT scanner also agree to this picture.
Numerical analysis of initial stage of thermal shock
NASA Astrophysics Data System (ADS)
Demidov, V. N.
2016-07-01
The paper studies a problem of a thermal shock at the surface of a half-space, which properties are described by elastic-plastic model taking into account dynamic effects, heat inertia, coupling between thermal and mechanical fields. The problem is solved numerically using finite-difference method of S.K. Godunov.
Noel, J.A.; Cole, J.; Innes, C.; Juzwick, S.
1987-09-01
In May 1986, the Ohio Board of Regents awarded a research grant to Ashland College to investigate the basinal origin of crude oil through trace-element analysis. The major thrust of the project was to attempt to finger print crude oils of various ages and depths from the northern Appalachian, eastern Illinois, and southern Michigan basins, to learn if the oldest crudes may have migrated among the basins. This in turn might give a more definitive time for the separation of the three basins. Nickel to vanadium ratios, were chosen to be the discriminators. Nickel to vanadium ratios show that the Trenton oil from the fields at Lima, Ohio; Oak Harbor in Ottawa County, Ohio; Urbana, Indiana; Peru, Indiana; and Albion, Michigan, are all different. The Trempealeau oils in Harmony and Lincoln Townships, Morrow County, are similar but they are different from those in Peru and Bennington Townships. The Devonian oils of the Illinois and Appalachian basins are distinctly different. The Berea oil shows little or no variability along strike. The Mississippian oils of the Illinois basin are different from the Berea oils and the Salem oil is different from the Chester. The only thing consistent about the Clinton is its inconsistency.
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.
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
Dartnell, P.; Gardner, J.V.
2009-01-01
The seafloor off greater Los Angeles, California, has been extensively studied for the past century. Terrain analysis of recently compiled multibeam bathymetry reveals the detailed seafloor morphology along the Los Angeles Margin and San Pedro Basin. The terrain analysis uses the multibeam bathymetry to calculate two seafloor indices, a seafloor slope, and a Topographic Position Index. The derived grids along with depth are analyzed in a hierarchical, decision-tree classification to delineate six seafloor provinces-high-relief shelf, low-relief shelf, steep-basin slope, gentle-basin slope, gullies and canyons, and basins. Rock outcrops protrude in places above the generally smooth continental shelf. Gullies incise the steep-basin slopes, and some submarine canyons extend from the coastline to the basin floor. San Pedro Basin is separated from the Santa Monica Basin to the north by a ridge consisting of the Redondo Knoll and the Redondo Submarine Canyon delta. An 865-m-deep sill separates the two basins. Water depths of San Pedro Basin are ??100 m deeper than those in the San Diego Trough to the south, and three passes breach a ridge that separates the San Pedro Basin from the San Diego Trough. Information gained from this study can be used as base maps for such future studies as tectonic reconstructions, identifying sedimentary processes, tracking pollution transport, and defining benthic habitats. ?? 2009 The Geological Society of America.
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.
Burrus, J. ); De Choppin, J.G.; Grosjean, J.L.; Oudin, J.L. ); Schwarzer, T. ); Schroeder, F.; Lander, R. )
1993-09-01
Integrated numerical modeling of petroleum, generation and migration is difficult to apply in deltaic series. Using Institut Francais du Petrole's two-dimensional model TEMISPACK, we tried to simulate the petroleum history along a 70 km long east-west regional section in the Mahakam delta (Indonesia) and a 800 km long north-south section in south Louisiana/Gulf of Mexico. The two basins contain thick (>10 km) accumulations of the post middle miocene. The principal results are as follows (1) Both basins have similar overpressure profiles caused by thick shales with nano-darcy permeabilities. Compaction, not oil or gas generation, controls the overpressure histories. (2) In both basins, the thermal history is dominated by burial rate, thermal blanketing, and undercompaction. Basinward increases in thermal gradients are probably due to basinward increases in shale content and undercompaction, rather than geodynamic processes. (3) We used an upscaling procedure to define sedimentary facies and properties for each cell in the models. In both cases, we found a huge permeability anisotropy of interbedded facies was necessary to match observed pressure profiles and hydrocarbon distributions. This anisotropy results in a dominant [open quotes]parallel-to-bedding[close quotes] migration pattern, with only a moderate (<0.5 km) vertical migration component. (4) A fundamental difference between the Mahakam and the Gulf coast petroleum systems is the hole of growth faults. In the Gulf Coast, huge growth faults connect deep overpressured, overmature Tertiary source facies with shallow, interbedded sandy reservoirs. Enhanced vertical permeability in the vicinity of these fault zones allows for several kilometers of vertical migration. In the Mahakam delta, where growth faults are less prevalent, deep overpressured shales have very poor expulsion efficiency; gas and oil in shallow reservoirs are shown to be fed mostly by coals located above, and not within, the overpressured zone.
NASA Astrophysics Data System (ADS)
Dodd, J. P.; Pollyea, R.
2014-12-01
The Atacama Desert of northern Chile is one of the driest regions on Earth and receives less than 5mm of precipitation annually. The Pampa del Tamarugal (PdT) Basin contains the largest aquifer system in the region, yet the mechanisms and timing of aquifer recharge and continental-scale groundwater flux are poorly understood. Although there is little debate that the source of groundwater recharge is the higher elevation regions of the Andean Altiplano to the east of the PdT Basin, there remains much uncertainty surrounding the mechanisms and timing of aquifer recharge and continental-scale groundwater flux. Most recharge models of the PdT focus on surface water runoff and alluvial fan recharge on shorter time scales, but many of these models explicitly neglect deep flow pathways. Previous investigators have combined the thermal aquifer profile and 14C groundwater ages to propose an alternative conceptual model in which cold meteoric water infiltrates deep into the Cordillera before circulating upward into the PdT by thermal convection through fault-controlled migration pathways. Although this conceptual model provides a convincing theoretical argument for deep fluid circulation, it cannot constrain the magnitude of this deep recharge flux. In this work, we revisit deep-flow conceptual model by combining the spatial distribution of hydrogen and oxygen isotope values as groundwater tracers with a non-isothermal model of continental scale groundwater flow through a two-dimensional transect from the Chilean Andes to the PdT Basin. This work provides first-order estimates on the contribution of deep groundwater circulation within the PdT Aquifer, while providing a framework for (1) quantifying boundary conditions for high resolution models of groundwater resources within the PdT Aquifer, (2) assessing the influence of variable future climate scenarios for groundwater availability in the region, and (3) further integrating conservative tracers and numerical models for
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)
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
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.
NASA Astrophysics Data System (ADS)
Oteng, F. M.; Yidana, S. M.; Alo, C. A.
2012-12-01
Effective development and informed management of groundwater resources represent a critical opportunity for improved rural water supply in Ghana and enhanced livelihoods particularly in the northern part of the White Volta Basin, a region already prone to a myriad of water-related infirmities. If adequately developed, the resource will form a sufficient buffer against the effects of climate change/variability and foster food security and sustainable livelihoods among the largely peasant communities in the region. This research presents the results of a preliminary assessment of the hydrogeological conditions and recharge regimes of the aquifers in the Northern parts of the White Volta Basin, Ghana. Results of estimates of groundwater recharge through the conventional isotopic and mass balance techniques are presented. Details of the groundwater flow pattern and preliminary delineation of local and regional groundwater recharge areas are presented from initial simulations of the hydrogeological system with a robust groundwater flow simulation code, MODFLOW, in the Groundwater Modeling System, GMS, version 7.1. The stream flow and evapotranspiration components of the program were activated to incorporate surface flow processes, so that the resulting model represents the conditions of the entire hydrological system. The results of this study form a platform for detailed numerical assessment of the conditions of the aquifers in the area under transient conditions of fluctuating rainfall patterns in the face of climate change/variability.
Numerical analysis of quench in coated conductors with defects
NASA Astrophysics Data System (ADS)
Liu, Wenbin; Yong, Huadong; Zhou, Youhe
2016-09-01
When the superconductor is subjected to local thermal perturbations, a large amount of joule heat may be generated in the conductor, which may lead to a quench. In a quench event, a normal zone irreversibly spreads throughout the conductor leading to failure of the superconducting device. In this paper, we will discuss the one-dimensional quench behavior in the coated conductors with internal defects or interface defects. Based on the numerical procedure given in the previous works, the normal zone propagation is studied by using the finite difference method. The numerical results are presented to discuss the normal zone propagation. We consider the effect of internal defect on the nonuniform temperature propagation. For the conductor with interface defects, it can be found that the normal zone propagation velocity is increased by defects.
Fourier analysis of numerical algorithms for the Maxwell equations
NASA Technical Reports Server (NTRS)
Liu, Yen
1993-01-01
The Fourier method is used to analyze the dispersive, dissipative, and isotropy errors of various spatial and time discretizations applied to the Maxwell equations on multi-dimensional grids. Both Cartesian grids and non-Cartesian grids based on hexagons and tetradecahedra are studied and compared. The numerical errors are quantitatively determined in terms of phase speed, wave number, propagation direction, gridspacings, and CFL number. The study shows that centered schemes are more efficient than upwind schemes. The non-Cartesian grids yield superior isotropy and higher accuracy than the Cartesian ones. For the centered schemes, the staggered grids produce less errors than the unstaggered ones. A new unstaggered scheme which has all the best properties is introduced. The study also demonstrates that a proper choice of time discretization can reduce the overall numerical errors due to the spatial discretization.
Algebraic multilevel preconditioning in isogeometric analysis: Construction and numerical studies
NASA Astrophysics Data System (ADS)
Gahalaut, K. P. S.; Tomar, S. K.; Kraus, J. K.
2013-11-01
We present algebraic multilevel iteration (AMLI) methods for isogeometric discretization of scalar second order elliptic problems. The construction of coarse grid operators and hierarchical complementary operators are given. Moreover, for a uniform mesh on a unit interval, the explicit representation of B-spline basis functions for a fixed mesh size $h$ is given for $p=2,3,4$ and for $C^{0}$- and $C^{p-1}$-continuity. The presented methods show $h$- and (almost) $p$-independent convergence rates. Supporting numerical results for convergence factor and iterations count for AMLI cycles ($V$-, linear $W$-, nonlinear $W$-) are provided. Numerical tests are performed, in two-dimensions on square domain and quarter annulus, and in three-dimensions on quarter thick ring.
Numerical Analysis of an Active Magnetic Regenerator (AMR) Refrigeration Cycle
NASA Astrophysics Data System (ADS)
Dikeos, J.; Rowe, A.; Tura, A.
2006-04-01
An alternative cycle proposed for refrigeration and gas liquefaction is active magnetic regenerator (AMR) refrigeration. This technology relies on solid materials exhibiting the magnetocaloric effect (MCE), a nearly reversible temperature change induced by a magnetic field change. This work focuses on numerical simulations of the AMR refrigeration cycle. A transient one-dimensional finite element model developed in FEMLAB™ incorporates energy equations for the refrigerant and the heat transfer fluid. The results of the model are validated by comparison to room temperature experiments with Gd. Predictions are then made for the performance of DyAl2 AMR beds near 70 K. Numerical results for simulations significantly above the Curie temperature are found to be dependent upon the initial conditions.
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.
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 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.
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 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
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.
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.
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
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
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.
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.
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.
Numerical analysis of Weyl's method for integrating boundary layer equations
NASA Technical Reports Server (NTRS)
Najfeld, I.
1982-01-01
A fast method for accurate numerical integration of Blasius equation is proposed. It is based on the limit interchange in Weyl's fixed point method formulated as an iterated limit process. Each inner limit represents convergence to a discrete solution. It is shown that the error in a discrete solution admits asymptotic expansion in even powers of step size. An extrapolation process is set up to operate on a sequence of discrete solutions to reach the outer limit. Finally, this method is extended to related boundary layer equations.
Error analysis of a ratio pyrometer by numerical simulation
Gathers, G.R. )
1992-01-01
A numerical method has been devised to evaluate measurement errors for a three-channel ratio pyrometer as a function of temperature. The pyrometer is simulated by computer codes, which can be used to explore the behavior of various designs. The influence of the various components in the system can be evaluated. General conclusions can be drawn about what makes a good pyrometer, and an existing pyrometer was evaluated, to predict its behavior as a function of temperature. The results show which combination of two channels gives the best precision. 13 refs., 12 figs.
Error analysis of a ratio pyrometer by numerical simulation
Gathers, G.R.
1990-05-01
A numerical method has been devised to evaluate measurement errors for a three channel ratio pyrometer as a function of temperature. The pyrometer is simulated by computer codes, which can be used to explore the behavior of various designs. The influence of the various components in the system can be evaluated. General conclusions can be drawn about what makes a good pyrometer, and an existing pyrometer was evaluated, to predict its behavior as a function of temperature. The results show which combination of two channels gives the best precision. 12 refs., 12 figs.
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.
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 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.
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 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.
Jones, Joseph L.; Johnson, Kenneth H.; Frans, Lonna M.
2013-01-01
A groundwater-flow model was developed to evaluate potential future effects of growth and of water-management strategies on water resources in the Chimacum Creek Basin. The model covers an area of about 64 square miles (mi2) on the Olympic Peninsula in northeastern Jefferson County, Washington. The Chimacum Creek Basin drains an area of about 53 mi2 and consists of Chimacum Creek and its tributary East Fork Chimacum Creek, which converge near the town of Chimacum and discharge to Port Townsend Bay near the town of Irondale. The topography of the model area consists of north-south oriented, narrow, regularly spaced parallel ridges and valleys that are characteristic of fluted glaciated surfaces. Thick accumulations of peat occur along the axis of East Fork Chimacum Creek and provide rich soils for agricultural use. The study area is underlain by a north-thickening sequence of unconsolidated glacial (till and outwash) and interglacial (fluvial and lacustrine) deposits, and sedimentary and igneous bedrock units that crop out along the margins and the western interior of the model area. Six hydrogeologic units in the model area form the basis of the groundwater-flow model. They are represented by model layers UC (upper confining), UA (upper aquifer), MC (middle confining), LA (lower aquifer), LC (lower confining), and OE (bedrock). Groundwater flow in the Chimacum Creek Basin and vicinity was simulated using the groundwater-flow model, MODFLOW-2005. The finite-difference model grid comprises 245 columns, 313 rows, and 6 layers. Each model cell has a horizontal dimension of 200 × 200 feet (ft). The thickness of model layers varies throughout the model area and ranges from 5 ft in the non-bedrock units to more than 2,400 ft in the bedrock. Groundwater flow was simulated for steady-state conditions, which were simulated for calibration of the model using average recharge, discharge, and water levels for the 180-month period October 1994–September 2009. The model as
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
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.
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.
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.
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.
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.
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
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 contaminant removal from fractured rock during boiling.
Chen, Fei; Falta, Ronald W; Murdoch, Lawrence C
2012-06-01
A multiphase heat transfer numerical model is used to simulate a laboratory experiment of contaminant removal at boiling temperatures from a rock core representing the matrix adjacent to a fracture. The simulated temperature, condensate production, contaminant and bromide concentrations are similar to experimental data. A key observation from the experiment and simulation is that boiling out approximately 1/2 pore volume (50 mL) of water results in the removal of essentially 100% of the dissolved volatile contaminant (1,2-DCA). A field-scale simulation using the multiple interacting continua (MINC) discretization approach is conducted to illustrate possible applications of thermal remediation of fractured geologic media, assuming uniform heating. The results show that after 28% of the pore water (including both steam vapor and liquid water) was extracted, and essentially all the 1,2-DCA mass (more than 99%) was removed.
A Numerical Analysis of a Light Slowing and Storage
NASA Astrophysics Data System (ADS)
Chough, Young-Tak
2015-12-01
We provide an in-depth numerical study on creation of stationary light pulses (SLP) in a cold atomic medium, locating the optimal parameter space for experimental realization. We visualize the dynamics of the atoms and the field inside the medium. We find that as the coupling field strength increases, the light slowing effect is actually diminished. It also turns out that the spatial profile of the pulse inside the medium is indeed not symmetric around its apex, and we point out that this asymmetry causes the energy imbalance between the two signals retrieved into the opposite directions, in addition to such extrinsic reasons as the disparity between the coupling field strengths or the imperfect centering of the pulse in the medium at the time of "writing".
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.
Thermoeconomic analysis of a CHP system by iterative numerical techniques
Damshala, P.R.
2000-07-01
This paper deals with the determination of the thermoeconomic optimum conditions for a constant space heat load imposed on the air coil of a combined heating and power (CHP) system using iterative numerical techniques. From the thermodynamic relations and equations derived from the energy balance and heat exchanger characteristics, an objective function and constraining equations are obtained. A computer program is developed based on the Redlich-Kwong equation of state to estimate the thermodynamic properties of the refrigerant fluid R-22. Additional computer subroutines are developed to perform thermodynamic and thermoeconomic optimization. Optimum values of the operating variables are identified at thermodynamic and thermoeconomic optimum conditions. Results show that the total irreversibilities produced in the system and the cost of fuel consumption are minimum at thermodynamic optimum conditions, but the annual cost of owning and operating the system is minimum at the thermoeconomic optimum condition, which is 34% lower than at the thermodynamic optimum condition.
Numerical analysis of Coleman-de Luccia tunneling
NASA Astrophysics Data System (ADS)
Goto, Yuhei; Okuyama, Kazumi
2016-08-01
In this paper, we study the false vacuum decay of a single scalar field ϕ coupled to gravity described by the Coleman-de Luccia (CdL) instanton. We show that it is possible to numerically calculate the bounce factor, which is related to the CdL tunneling rate, without using the thin-wall approximation. In this paper, we consider 1/cosh(ϕ)- and cos(ϕ)-type potentials as examples, which have cosmological and phenomenological applications. Especially, in the cos(ϕ)-type potential, we show that the range of values in which axion decay constant can take is restricted by the form of the periodic potential if the CdL tunneling occurs.
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
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.
Mathematical analysis and numerical simulation of a model of morphogenesis.
Muñoz, Ana I; Tello, José Ignacio
2011-10-01
We consider a simple mathematical model of distribution of morphogens (signaling molecules responsible for the differentiation of cells and the creation of tissue patterns). The mathematical model is a particular case of the model proposed by Lander, Nie and Wan in 2006 and similar to the model presented in Lander, Nie, Vargas and Wan 2005. The model consists of a system of three equations: a PDE of parabolic type with dynamical boundary conditions modelling the distribution of free morphogens and two ODEs describing the evolution of bound and free receptors. Three biological processes are taken into account: diffusion, degradation and reversible binding. We study the stationary solutions and the evolution problem. Numerical simulations show the behavior of the solution depending on the values of the parameters.
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.
Fracture analysis of the upper devonian antrim shale, Michigan basin
Richards, J.A.; Budai, J.M.; Walter, L.M.; Abriola, L.M. )
1994-08-01
The Antrim Shale is a fractured, unconventional gas reservoir in the northern Michigan basin. Controls on gas production are poorly constrained but must depend on the fracture framework. Analyses of fracture geometry (orientation, spacing, and aperture width) were undertaken to better evaluate reservoir permeability and, hence, pathways for fluid migration. Measurements from nearly 600 fractures were made from outcrop, core, and Formation MicroScanner logs covering three members of the Antrim Shale (Norwood, Paxton, Lachine) and the Ellsworth Shale. Fracture analyses indicate pronounced reservoir anisotropy among the members. Together related with lithologic variations, this leads to unique reservoir characteristics within each member. There are two dominant fracture sets, northeast-southwest and northwest-southeast. Fracture density varies among stratigraphic intervals but always is lowest in the northwest-southeast fracture set and is greatest in the northeast-southwest fracture set. While aperture width decreases markedly with depth, subsurface variation in mean aperture width is significant. Based on fracture density and mean aperture width, the Norwood member has the largest intrinsic permeability and the Ellsworth Shale the lowest intrinsic permeability. The highest intrinsic fracture permeability in all intervals is associated with the northeast-southwest fracture set. The Norwood and Lachine members thus exhibit the best reservoir character. This information is useful in developing exploration strategies and completion practices in the Antrim Shale gas play.
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.
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
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 ...
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)
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.
Numerical analysis of hypersonic turbulent film cooling flows
NASA Technical Reports Server (NTRS)
Chen, Y. S.; Chen, C. P.; Wei, H.
1992-01-01
As a building block, numerical capabilities for predicting heat flux and turbulent flowfields of hypersonic vehicles require extensive model validations. Computational procedures for calculating turbulent flows and heat fluxes for supersonic film cooling with parallel slot injections are described in this study. Two injectant mass flow rates with matched and unmatched pressure conditions using the database of Holden et al. (1990) are considered. To avoid uncertainties associated with the boundary conditions in testing turbulence models, detailed three-dimensional flowfields of the injection nozzle were calculated. Two computational fluid dynamics codes, GASP and FDNS, with the algebraic Baldwin-Lomax and k-epsilon models with compressibility corrections were used. It was found that the B-L model which resolves near-wall viscous sublayer is very sensitive to the inlet boundary conditions at the nozzle exit face. The k-epsilon models with improved wall functions are less sensitive to the inlet boundary conditions. The testings show that compressibility corrections are necessary for the k-epsilon model to realistically predict the heat fluxes of the hypersonic film cooling problems.
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 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 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.
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.
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.
Numerical analysis of mixing enhancement for micro-electroosmotic flow
NASA Astrophysics Data System (ADS)
Tang, G. H.; He, Y. L.; Tao, W. Q.
2010-05-01
Micro-electroosmotic flow is usually slow with negligible inertial effects and diffusion-based mixing can be problematic. To gain an improved understanding of electroosmotic mixing in microchannels, a numerical study has been carried out for channels patterned with wall blocks, and channels patterned with heterogeneous surfaces. The lattice Boltzmann method has been employed to obtain the external electric field, electric potential distribution in the electrolyte, the flow field, and the species concentration distribution within the same framework. The simulation results show that wall blocks and heterogeneous surfaces can significantly disturb the streamlines by fluid folding and stretching leading to apparently substantial improvements in mixing. However, the results show that the introduction of such features can substantially reduce the mass flow rate and thus effectively prolongs the available mixing time when the flow passes through the channel. This is a non-negligible factor on the effectiveness of the observed improvements in mixing efficiency. Compared with the heterogeneous surface distribution, the wall block cases can achieve more effective enhancement in the same mixing time. In addition, the field synergy theory is extended to analyze the mixing enhancement in electroosmotic flow. The distribution of the local synergy angle in the channel aids to evaluate the effectiveness of enhancement method.
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.
A numerical analysis of crack growth in brittle microcracking composites
Biner, S.B.
1993-04-01
A set of numerical analyses of crack growth was performed to elucidate the mechanism of microcracking on the observed fracture behavior of brittle solids and composites. The random nucleation, orientation and size effects of discrete microcracks and resulting interactions are fully accounted for in a hybrid finite element model. The results indicate that the energy expenditure due the microcrack nucleation seems not to contribute significantly to the resistance to crack growth. The main controlling parameter appears to be elastic interaction of the microcracks with the main crack in the absence of a reinforcing phase; therefore, the microcrack density plays an important role. In the case of the composites, the interaction of the main crack with the stress fields of the reinforcing phase, rather than interaction of microcracks, is the controlling parameter for the resistance to the crack growth even in the presence of a large population of microcracks. It will be also shown that the crack branching and crack kinking can readily develop as a result of microcracking.
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
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.
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.
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
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.
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.
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
Process-based distributed modeling approach for analysis of sediment dynamics in a river basin
NASA Astrophysics Data System (ADS)
Kabir, M. A.; Dutta, D.; Hironaka, S.
2010-08-01
Modeling of sediment dynamics for developing best management practices of reducing soil erosion and of sediment control has become essential for sustainable management of watersheds. Precise estimation of sediment dynamics is very important since soils are a major component of enormous environmental processes and sediment transport controls lake and river pollution extensively. Different hydrological processes govern sediment dynamics in a river basin, which are highly variable in spatial and temporal scales. This paper presents a process-based distributed modeling approach for analysis of sediment dynamics at river basin scale by integrating sediment processes (soil erosion, sediment transport and deposition) with an existing process-based distributed hydrological model. In this modeling approach, the watershed is divided into an array of homogeneous grids to capture the catchment spatial heterogeneity. Hillslope and river sediment dynamic processes have been modeled separately and linked to each other consistently. Water flow and sediment transport at different surface grids and river nodes are modeled using one-dimensional kinematic wave approximation of Saint-Venant equations. The mechanics of sediment dynamics are integrated into the model using representative physical equations after a comprehensive review. The model has been tested on river basins in two different hydro climatic areas, the Abukuma River Basin, Japan and Latrobe River Basin, Australia. Sediment transport and deposition are modeled using Govers transport capacity equation. All spatial datasets, such as, Digital Elevation Model (DEM), land use and soil classification data, etc., have been prepared using raster "Geographic Information System (GIS)" tools. The results of relevant statistical checks (Nash-Sutcliffe efficiency and R-squared value) indicate that the model simulates basin hydrology and its associated sediment dynamics reasonably well. This paper presents the model including
Process-based distributed modeling approach for analysis of sediment dynamics in a river basin
NASA Astrophysics Data System (ADS)
Kabir, M. A.; Dutta, D.; Hironaka, S.
2011-04-01
Modeling of sediment dynamics for developing best management practices of reducing soil erosion and of sediment control has become essential for sustainable management of watersheds. Precise estimation of sediment dynamics is very important since soils are a major component of enormous environmental processes and sediment transport controls lake and river pollution extensively. Different hydrological processes govern sediment dynamics in a river basin, which are highly variable in spatial and temporal scales. This paper presents a process-based distributed modeling approach for analysis of sediment dynamics at river basin scale by integrating sediment processes (soil erosion, sediment transport and deposition) with an existing process-based distributed hydrological model. In this modeling approach, the watershed is divided into an array of homogeneous grids to capture the catchment spatial heterogeneity. Hillslope and river sediment dynamic processes have been modeled separately and linked to each other consistently. Water flow and sediment transport at different land grids and river nodes are modeled using one dimensional kinematic wave approximation of Saint-Venant equations. The mechanics of sediment dynamics are integrated into the model using representative physical equations after a comprehensive review. The model has been tested on river basins in two different hydro climatic areas, the Abukuma River Basin, Japan and Latrobe River Basin, Australia. Sediment transport and deposition are modeled using Govers transport capacity equation. All spatial datasets, such as, Digital Elevation Model (DEM), land use and soil classification data, etc., have been prepared using raster "Geographic Information System (GIS)" tools. The results of relevant statistical checks (Nash-Sutcliffe efficiency and R-squared value) indicate that the model simulates basin hydrology and its associated sediment dynamics reasonably well. This paper presents the model including descriptions
Numerical analysis of electrically tunable aspherical optofluidic lenses.
In this work, we use the numerical simulation platform Zemax to investigate the optical properties of electrically tunable aspherical liquid lenses, as we recently reported in an experimental study [
2016-06-27
In this work, we use the numerical simulation platform Zemax to investigate the optical properties of electrically tunable aspherical liquid lenses, as we recently reported in an experimental study [
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
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
Von Der Dick, H.; Callejon-Gimenez, A.; Bosman, D.
1996-08-01
Traditional exploration techniques in near surface gas surveys usually apply hydrocarbon (HC) gas concentrations and HC gas ratios to extract information relevant to exploration. Although gas surveys are sometimes used to define exploration fairways or to evaluate prospects, nearsurface data are often misleading and prone to misinterpretation. This is largely the result of a poor understanding of the origin, distribution and fate of HC gases in near surface regime. We report new numerical techniques based on unmixing algorithms that allow for the discrimination and determination of individual gas sources in near surface sediments. Results clearly show a variety of HC gas sources that build up complex gas compositions and gas associations in this shallow environment. The bulk of non-seepage related HC gases is discriminated from a (usually) small fraction of shallow HC gases related to seepage. Model calculations are used to systematically search for a defined seepage signal in these gas data sets. This technique, termed GEL (Geochemical Exploration Lead), is described and exploration examples are provided from the Llanos area, Venezuela. Drilling results on some anomalies show commercial deep oil reservoirs with very low gas/oil - ratio. The prognosis of the well status clearly points to an increased success ratio when GEL data are incorporated into seismic/geologic information.
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.
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.
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.
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.
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.
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.
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.
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.
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 analysis for in-plane behavior of infilled frames
Jamal, B.D.; Bennett, R.M.; 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.
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.
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.
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
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.
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.
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)
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. 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. 25 refs., 14 figs., 22 tabs.
Numerical Analysis of Microwave Heating on Saponification Reaction
NASA Astrophysics Data System (ADS)
Huang, Kama; Jia, Kun
2005-01-01
Currently, microwave is widely used in chemical industry to accelerate chemical reactions. Saponification reaction has important applications in industry; some research results have shown that microwave heating can significantly accelerate the reaction [1]. But so far, no efficient method has been reported for the analysis of the heating process and design of an efficient reactor powered by microwave. In this paper, we present a method to study the microwave heating process on saponification reaction, where the reactant in a test tube is considered as a mixture of dilute solution. According to the preliminary measurement results, the effective permittivity of the mixture is approximately the permittivity of water, but the conductivity, which could change with the reaction, is derived from the reaction equation (RE). The electromagnetic field equation and reaction equation are coupled by the conductivity. Following that, the whole heating processes, which is described by Maxwell's equations, the reaction equation and heat transport equation (HTE), is analyzed by finite difference time domain (FDTD) method. The temperature rising in the test tube are measured and compared with the computational results. Good agreement can be seen between the measured and calculated results.
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.
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.
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.
NASA Astrophysics Data System (ADS)
Dutta, Dushmanta; Herath, Srikantha; Musiake, Katumi
2006-04-01
An application of a flood risk analysis system is presented for the analysis on the impact of a proposed flood control plan in the Ichinomiya river basin, Chiba Prefecture, Japan. The system consists of two main modules: a physically based distributed hydrological model for flood inundation and a geographical information system (GIS)-based raster model for flood loss estimation. In the system, the grid-based distributed hydrological model simulates surface flood inundation parameters for user-specified spatial and temporal resolutions. At the end of each time step the simulated flood parameters in each grid are transferred to the GIS-based model for economic loss estimation. The proposed flood control plan consisted of three structural measures. These measures were then incorporated into the system to analyze their impacts on the reduction of flood inundation and resulting economic impacts for 50-year and 100-year return-period rainfall scenarios in the basin. From the analyses, it was found that the proposed flood control plan can reduce flood inundation in the basin for 50-year and 100-year return-period rainfalls to a great extent, and the resulting urban and agriculture damage in the basin can be reduced by over 70%.
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.
McCrory, P.A.
1989-01-01
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. -from Author
Numerical analysis and control for cantilever flexible beams using PZT patches
NASA Astrophysics Data System (ADS)
Yan, Shi; Zhang, Hao
2008-03-01
This paper presents a numerical study on a vibration control of a cantilever flexible beam using PZT patches. The PZT patches used as both actuators and sensors were adopted in the forms of surface-bond devices on the flexible aluminum beam to control actively the vibration responses. The beam was actuated electrically by the PZT actuator to generate the vibration and the feedback signals were collected by the PZT sensors during the numerical analysis and experimental validation. A finite element method (FEM) in which the materials of the beam and PZTs were coupled was used numerically to analyze the vibration and structural control. A compare study between the numerical simulation and experiment results was finished. The results of the FEM simulation showed that it was effective to use PZT patches to control the responses of flexible structure and the proposed numerical method was also successful in analyzing the vibration responses of the coupled material structures.
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 Technical Reports Server (NTRS)
Gassaway, J. D.
1976-01-01
An analysis is presented which is based upon a numerical solution of Gauss's law for the multiple dielectric semiconductor and electrode structure. The formulation resulted in a large set of equations, usually nonlinear, which were solved by an iterative scheme based upon the Gauss-Seidel method employing a relaxation parameter. Proper consideration of the nonlinearity of the space-charge in the semiconductor allowed convergent solutions which can give reasonable approximations to the channel potential profiles though not as good for estimating the space charge itself. The results of this work, which are three computer programs, are listed. None of the programs give the electric field explicitly as output data. However, when this information is desired, the programs can be expanded to include field estimations based on a polynominal fit to the potential field, or they may serve as subprograms for main programs dealing with general aspects of charge transfer.
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
NASA Astrophysics Data System (ADS)
Curto, J. B.; Blakely, R. J.; Vidotti, R. M.; Fuck, R. A.
2015-12-01
The South American Platform includes two major geological components with common structural roots: the Transbrasiliano Lineament (LTB) and the Paraná Basin. Important relationships between the two components occur within the northwest Paraná Basin and concealed beneath sedimentary cover. We integrated all available airborne magnetic and gravity surveys and ground-based gravity data to produce consistent, digital magnetic and Bouguer anomaly maps. Data-processing and modeling techniques then were used in order to reveal principal crustal compartments and basin-basement structures at various depths. Three large magnetic discontinuities delineate crustal compartments in the area with N30°E, N60°E, and N70°E strike, from east to west, respectively. These magnetic lineaments bound regions with distinct gravity anomaly character. Robust matched-filter analysis applied to magnetic and gravity data yielded important depth estimates: (i) 2.5 km to the top of the Paraná Basin Neoproterozoic basement; (ii) 4-6 km to the top of a second group of basement units; (iii) 20 km, possibly associated with the upper-lower crust interface; and (iv) 33-39 and 43 km related to crustal thicknesses west and southeast of a major N30°E trending lineament, respectively. The 2D joint modeling of gravity and magnetic data sheds light on the asymmetric geometry of the basement beneath the Paraná basin, with at least three half-grabens formed by LTB reactivated structures. The central region of the study area is characterized by thinner crust and higher crustal weakness, where important structures have developed in the Mesozoic, including NW trending reactivations, linked to crustal uplift and evolution of small NE-aligned Cretaceous basins. Important depocenters occur to the north and east of the study area, with N70ºE and N30°E - NS strike, respectively.
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.
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
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.
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.
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.
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
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.
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.
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.
Twumasi, Yaw A; Merem, Edmund C
2008-03-01
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.
Analysis of Long-term Terrestrial Water Storage Variations in the Yangtze River Basin
NASA Astrophysics Data System (ADS)
Su, Bob; Huang, Ying; Wang, Lichun; Salama, Suhyb; Krol, Maaten; Hoekstra, Arjen; Zhou, Yunxuan; van der Velde, Rogier
2014-05-01
In this study, we analyze 32 years of TWS data obtained from Interim Reanalysis Data (ERA-Interim) and Noah model from Global Land Data Assimilation System (GLDAS-Noah) for the period between 1979 and 2010. The accuracy of these datasets is validated against 26 years (1979-2004) of runoff dataset from Yichang gauging station and compared to 32 years of independent precipitation data obtained from Global Precipitation Climatology Centre Full Data Reanalysis Version 6 (GPCC) and NOAA's PRECipitation REConstruction over Land (PREC/L). Spatial and temporal analysis of the TWS data shows that TWS in the Yangtze River basin is decreasing significantly since the year 1998. The driest period of the basin is noted from 2005 to 2010, especially in the middle and lower Yangtze reaches. The TWS changed abruptly into persistently high negative anomalies in the middle and lower Yangtze Reaches in 2004. From both basin and annual perspectives, 2006 is detected as the major inflection point at which the system exhibits a persistent decrease in TWS. Comparing these TWS trends to independent precipitation datasets shows that the recent decrease in TWS can mainly be attributed to a decrease in precipitation amount. Our finding is based on observation and modeling data sets and confirms previous results based on gauging station datasets. Reference: Huang, Y., Salama, M.S., Krol, M.S., van der Velde, R., Hoekstra, A.Y., Zhou, Y. and Su, Z. (2013) Analysis of long - term terrestrial water storage variations in the Yangtze River basin. In: Hydrology and earth system sciences (HESS): 17 (2013)5 pp. 1985-2000.
An Analysis of Two Schemes to Numerically Solve the Stochastic Collection Growth Equation.
NASA Astrophysics Data System (ADS)
de Almeida, Fausto Carlos; Dennett, Roger D.
1980-12-01
Two schemes for the numerical solution of the stochastic collection growth equation for cloud drops are compared. Their numerical approaches are different. One (the Berry/Reinhardt method) emphasizes accuracy; the other (the Bleck method) emphasizes speed. Our analysis shows that for applications where the number of solutions (time steps) does not exceed 104 the accuracy-oriented scheme is faster. For larger, repetitive applications, such as a comprehensive cloud model, an objective analysis can be made on the merits of exchanging accuracy for computational time.
Numerical and asymptotic analysis of the 't Hooft-Polyakov magnetic monopole
NASA Astrophysics Data System (ADS)
Forgács, P.; Obadia, N.; Reuillon, S.
2005-02-01
A high precision numerical analysis of the static, spherically symmetric SU(2) magnetic monopole equations is carried out. Using multishooting and multidomain spectral methods, the mass of the monopole is obtained rather precisely as a function of β=MH/MW for a large β-interval (MH and MW denote the mass of the Higgs and gauge field, respectively). The numerical results necessitated the reexamination and subsequent correction of a previous asymptotic analysis of the monopole mass in the literature for β≪1.
Numerical analysis of the steam flow field in shell and tube heat exchanger
NASA Astrophysics Data System (ADS)
Bartoszewicz, Jarosław; Bogusławski, Leon
2016-06-01
In the paper, the results of numerical simulations of the steam flow in a shell and tube heat exchanger are presented. The efficiency of different models of turbulence was tested. In numerical calculations the following turbulence models were used: k-ɛ, RNG k-ɛ, Wilcox k-ω, Chen-Kim k-ɛ, and Lam-Bremhorst k-ɛ. Numerical analysis of the steam flow was carried out assuming that the flow at the inlet section of the heat exchanger were divided into three parts. The angle of steam flow at inlet section was determined individually in order to obtain the best configuration of entry vanes and hence improve the heat exchanger construction. Results of numerical studies were verified experimentally for a real heat exchanger. The modification of the inlet flow direction according to theoretical considerations causes the increase of thermal power of a heat exchanger of about 14%.
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.
A multivariate statistical analysis of surface water chemistry data--the Ankobra Basin, Ghana.
Yidana, Sandow M; Ophori, Duke; Banoeng-Yakubo, Bruce
2008-01-01
R-mode hierarchical cluster and principal component analysis (PCA) were simultaneously applied to surface water hydrochemical data from three different locations, Ankwaso, Dominase and Prestea, along the Ankobra Basin, Ghana, to extract principal factors corresponding to the different sources of variation in the hydrochemistry, with the objective of defining the main controls on the hydrochemistry at the basin scale. Using the Kaiser criterion, principal components (PC) were extracted from the data and rotated using varimax normalization, for each location. The varimax rotation ensured that variation in the data was maximized for easy interpretation of the results. The analysis reduced 30, 33 and 33 data points, respectively, for Ankwaso, Dominase and Prestea to four, three and four PC representing the sources of variation in the hydrochemistry at the three different locations. Though the PC analysis proved to be more robust at unveiling the sources of variation in the hydrochemistry than the R-mode hierarchical cluster analysis (HCA), the combined use of both techniques resulted in more reliable interpretations of the hydrochemistry. On the basis of these analyses, the hydrochemistry of the basin is controlled largely by the weathering of minerals (silicates, carbonates, gypsum and apatite) from the underlying meta-sediments of the Birimian and Tarkwaian Systems, and the decay of organic matter from the heavily forested regions. Concentrations of the major chemical parameters are within naturally acceptable limits and do not pose threats to the local ecology and humans. There is no strong evidence of high anthropogenic impacts on the major anions and cations used for this research, though there are variations at the different locations studied. The hydrochemistry at Ankwaso is principally controlled by the weathering of silicate minerals, whereas those of Dominase and Prestea are, respectively, influenced by precipitation and domestic wastewaters, and the decay of
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
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.
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
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
Numerical analysis of two-phase flow in networks. Final report
Porsching, T.A.
1984-09-01
Many computer programs that simulate the thermal and hydraulic behavoir of LWR systems employ network models of homogeneous or two-fluid two-phase flow. Part I of this report documents a new numerical for such homogeneous models. The technique is based on the Dual Variable Method developed under a previous EPRI Reseach Project. The analysis shows that the new method is both robust and efficient. A set of three numerical simulations involving a fast transient, a slow transient and a phase boundary crossing support the analysis. Part II presents a systematic derivation of a two-fluid network model that exactly conserves the mass and total energy of the moisture in the network. Two numerical examples are presented to illustrate its use.
Water-quality assessment of the Potomac River Basin: analysis of available pesticide data, 1972-1990
Zappia, Humbert; Fisher, Gary T.
1997-01-01
A study of available data for the period from 1972 to 1990 was conducted to characterize the occurrence and distribution of pesticides in sur-face water, bottom material, ground water, and fish tissue in the Potomac River Basin. The study was conducted by the Potomac River study unit of the U.S. Geological Survey?s National Water-Quality Assessment (NAWQA) program. Exist-ing data coverage was evaluated to guide future data-collection activities. Data from computer data bases and from published and unpublished reports were obtained from local, State, and Fed-eral agencies in the four Potomac River Basin states and the District of Columbia. Data are available for all environmental media, but geo-graphic and temporal coverage are limited. Clusters of data occur in the north-central parts of the basin, with numerous samples at discrete loca-tions in the Shenandoah and Monocacy River Basins, along the mainstem Potomac River, in the Washington, D.C., area, and in streams along the Potomac Estuary. Much of the available surface-water and bottom-material data are from the ear-lier years of the period of interest, the ground-water data are from the middle years, and the fish-tissue data are distributed over much of the period. Overall, temporal coverage is not sufficient for analysis of trends. Comparisons between different sample media are possible in some areas of the Potomac River Basin, particularly in the northern end of the Great Valley. Residual concentrations of some pesticides have been found in surface water, bottom mate-rial, ground water, and fish tissue. Samples have been analyzed for a total of at least 69 pesticides and related compounds in surface water, bottom material, ground water, and fish tissue. Most con-centrations of the pesticides analyzed during the period from 1972 to 1990 were less than or equal to reporting limits. For surface-water samples, 13 out of 41 pes-ticides and related compounds analyzed had concentrations equal to or greater than the
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.
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.
NASA Astrophysics Data System (ADS)
Dombrowsky, Ines; Almog, Ram; Becker, Nir; Feitelson, Eran; Klawitter, Simone; Lindemann, Stefan; Mutlak, Natalie
2010-05-01
The basin scale has been promoted universally as the optimal management unit that allows for the internalization of all external effects caused by multiple water uses. However, the basin scale has been put forward largely on the basis of experience in temperate zones. Hence whether the basin scale is the best scale for management in other settings remains questionable. To address these questions this paper analyzes the economic viability and the political feasibility of alternative management options in the Kidron/Wadi Nar region. The Kidron/Wadi Nar is a small basin in which wastewater from eastern Jerusalem flows through the desert to the Dead Sea. Various options for managing these wastewater flows were analyzed ex ante on the basis of both a cost benefit and a multi-criteria analysis. The paper finds that due to economies of scale, a pure basin approach is not desirable from a physical and economic perspective. Furthermore, in terms of political feasibility, it seems that the option which prompts the fewest objections from influential stakeholder groups in the two entities under the current asymmetrical political setting is not a basin solution either, but a two plant solution based on an outsourcing arrangement. These findings imply that the river basin management approach can not be considered the best management approach for the arid transboundary case at hand, and hence is not unequivocally universally applicable.
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.
Structure of unilamellar vesicles: Numerical analysis based on small-angle neutron scattering data
Zemlyanaya, E. V. Kiselev, M. A.; Zbytovska, J.; Almasy, L.; Aswal, V. K.; Strunz, P.; Wartewig, S.; Neubert, R.
2006-12-15
The structure of polydispersed populations of unilamellar vesicles is studied by small-angle neutron scattering for three types of lipid systems, namely, single-, two-and four-component vesicular systems. Results of the numerical analysis based on the separated-form-factor model are reported.
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.
Synoptic climatological analysis of the high level winds over the Carpathian Basin
NASA Astrophysics Data System (ADS)
Zsilinszki, Anna; Soósné Dezsö, Zsuzsanna; Bartholy, Judit; Pongrácz, Rita
2016-04-01
In recent years several „unusual" weather events have been recorded in the Carpathian Basin, e.g. severe snow in March 2013. In this paper we evaluate the hypothesis assuming that these weather events are related to the high level winds, especially, to the characterictics of the polar jet-stream. For this puspose, first, we performed a general statistical analysis of the high level wind fields of the region for 18 vertical layers above the 500 hPa pressure level, including the detaled analysis of average wind speed and wind directions, trend analysis of daily wind speed values, and extreme wind speed values. In addition, we examined the relationship between the regional climatic conditions and the jet stream, for which we used NAO (North Atlantic Oscillation) and AO (Arctic Oscillation) indices for first estimations since these teleconnection pattern indices are closely related to the jet-stream. We calculated linear correlation coefficients between NAO and AO indices, and local weather conditions for 30 years (1981-2010) on annual, seasonal, and monthly time scales as well as for special cases. Our final goal is to evaluate the possible effects of climate change on the high level winds, and thereby the weather conditions in the Carpathian Basin.
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
Numerical models of diapiric structures - analysis of the finite strain distribution
NASA Astrophysics Data System (ADS)
Fuchs*, L.; Schmeling, H.
2012-04-01
In gravity driven tectonic structures finite strain is a key parameter to understand the evolution of the underlying dynamic processes. In the study conducted here, the strain was analyzed numerically for two different diapiric models, the model of a classical Rayleigh-Taylor instability [1], which is mainly important for magmatic diapirs, and the down-building model [2], which is especially important for salt diapirs where the rise is driven by differential sediment loading. The equations of conservation of mass, momentum, and composition are solved by a 2D finite difference code (FDCON) based on a stream function formulation in combination with a marker approach based on a predictor-corrector Runge-Kutta 4th order scheme. The finite deformation was determined using the algorithm of McKenzie [3] calculated centered in time and in space, where the information of the deformation matrix is advected with the markers in the model. Two series of different viscosity contrasts m = ηbuoyant ηtop and different thicknesses were calculated for each hbuoyant of a Rayleigh-Taylor like instability with both no slip and free slip boundary conditions at the top and bottom. In the case of the down-building models we present two model series with different viscosity regimes: one with a stiff subsiding sediment layer, with the result of high deformation within the salt and negligible deformation in the ambient sediments and another with relatively weak sediments, in which the deformation is partitioned between the salt and the sediments. In addition to the local analysis of the strains in each layer, the strain partitioning is considered on the entire volume of the two layers. Therefore the maximum shear strain [4] is integrated in each layer and forms the ratio Sr between the integrated values of the upper and lower layer. This ratio provides information on how the strain is distributed between the two layers. For the RTI models the maximum values of the finite deformation inside
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
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
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.
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 secondary flow in a two-stage turbine
NASA Technical Reports Server (NTRS)
Kirtley, K. R.; Beach, T. A.; Adamczyk, J. J.
1990-01-01
The three-dimensional viscous average passage flow in the Pratt and Whitney alternate design Space Shuttle Main Engine fuel turbine has been simulated. The effect of secondary flows generated by upstream blade rows on the performance of downstream blade rows is studied. The numerical results are compared to the design intent to validate improved models in the average passage equations. Analysis of the results centers on the primary spanwise mixing mechanism in this low aspect ratio turbine. A multigrid method has also been incorporated to improve the overall convergence rate of the numerical algorithm.
Analysis of the numerical effects of parallelism on a parallel genetic algorithm
Hart, W.E.; Belew, R.K.; Kohn, S.; Baden, S.
1995-09-18
This paper examines the effects of relaxed synchronization on both the numerical and parallel efficiency of parallel genetic algorithms (GAs). We describe a coarse-grain geographically structured parallel genetic algorithm. Our experiments show that asynchronous versions of these algorithms have a lower run time than-synchronous GAs. Furthermore, we demonstrate that this improvement in performance is partly due to the fact that the numerical efficiency of the asynchronous genetic algorithm is better than the synchronous genetic algorithm. Our analysis includes a critique of the utility of traditional parallel performance measures for parallel GAs, and we evaluate the claims made by several researchers that parallel GAs can have superlinear speedup.
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.
NASA Astrophysics Data System (ADS)
Belov, S.; Donchytz, G.; Kivva, S.; Kuschan, A.; Zheleznyak, M.
2003-04-01
The implementation of new flood forecasting systems for the Ukrainian part of the Tisza basin has started last years by the customisation of Mike-11 model for the Uzh River and Latoritsa River (part of the Bodrog Catchment) in the frame of the joint project with the 'DHI Water&Environment'. The calibration and testing of the lumped parameter model NAM was provided in collaboration with the Ukrainian Hydrometcenter and the Uzhgorod Hydrometcenter for the period 1998-2000, which includes two hazardous floods of years 1998 and 2000. The tuning of hydrodynamical module of Mike-11 is provided in collaboration with the Transcarpathian Branch of State Committee of Water Management (SCWM), Uzhgorod. The information about existing and designed hydraulic structures in the river channels, -bridges, polders, dikes, pump stations is used for the model tuning. The flood forecasting system for Uzh River and Latoritsa River based on Mike -11 is in pre-operational use in Uzhgorod Hydromet and SCUWM offices. The advance time of the flood forecasts can be increased by the real-time assimilation of the precipitation forecasts of a Numerical Weather Predictions (NWP) model. The Penn State University /UCAR NWP model MM5 was customized for the Ukrainian territory in resolution 30*30 km on the basis of the rare gridded forecasting data from the German meteorological center Offenbach, assimilating the data from the Ukrainian meteorological stations, processed by the Ukrainian Hydrometcenter. The region of the Uzh and Latoritsa watersheds was simulated by MM5 in the resolution 10*10 km for the linking with the Mike -11 (NAM). The preliminary results of flood forecasting on the basis of the meteorological forecasts are analyzed. For further improvement of the flood forecasting systems the implementations of GIS based distributed models are planned. Two types of distributed models based upon physically meaningful parameters are comparatively studied- 2-D finite- difference model RUNTOX (Kivva
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
NASA Astrophysics Data System (ADS)
Daams, R.; Díaz-Molina, M.; Mas, R.
1996-03-01
A detailed stratigraphic and sedimentological analysis is given of Late Oligocene to Early Miocene continental sediments in a small area (1 km 2) of the Loranca Basin (Province of Cuenca). The studied exposure is a part of the Tórtola fluvial fan and mainly consists of superimposed meander belt sediments. The ages of base and top of the sedimentary succession were obtained by a combination of biostratigraphic and palaeomagnetic data, thus allowing us to estimate the mean sedimentation rates of the section (10 cm/ka). Our estimation of the sediment accumulation rate based on the analysis of palaeosols (18 cm/ka) appears to be reasonably reliable for short-term accumulation rates. The small size of palaeochannels and the relatively wide basin section may have allowed the development of a distributary fluvial system and may have caused the low vertical recurrence of relatively episodic sedimentation. The time interval covered by the sediments studied shows a progressive trend toward drier conditions and higher temperatures, inferred from qualitative and quantitative changes in fossil rodent faunas. These trends coincide with a gradual decrease of maximum values of estimated discharge of our fluvial systems. In these sediments it is dangerous to establish a correlation between the detected possible climatic changes and Milankovitch cycles. This is due to the low sedimentation rate and the frequent discontinuities in our stratigraphic record.
NASA Astrophysics Data System (ADS)
Chaibou Begou, Jamilatou; Jomaa, Seifeddine; Benabdallah, Sihem; Bazie, Pibgnina; Afouda, Abel; Rode, Michael
2016-04-01
The objective of this study was to determine physiographic similarity, as indicator of hydrologic similarity between catchments located in the Bani basin, and to derive the dominant factors controlling each group singularity. We utilized a dataset of 28 catchments described by 16 physical and climatic properties distributed across a wide region with strong environmental gradients. Catchments attributes were first standardized before they underwent an integrated exploratory data analysis composed by Principal Component Analysis (PCA) followed by Hierarchical Clustering. Results showed a clear distribution into 3 major clusters. Two of them were well separated and partitioned into northerly flat and semi-arid catchments, and southerly hilly and humid catchments. This nomenclature came from the interpretation of the main factors, topography, precipitation and latitude, which seem to control the most important variability inside these clusters. Moreover, the group of northerly catchments was designated to be dominated by agricultural land use and ferric luvisols soil type, two additional drivers of similarity. The third cluster was located in the center of the study basin, inside which, none of the descriptors seems to exert a strong control on the similarity. The outcome of this study can help understanding catchment functioning and provide a support for a regionalization of hydrological information.
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.
A Numerical Analysis on Freezing Behavior of Flowing Water inside a Pipe Cooled from Surroundings
NASA Astrophysics Data System (ADS)
Chiba, Ryoichi; Izumi, Masaaki
A freezing phenomenon in forced convectional flow inside a pipe is investigated numerically in this paper .The numerical analysis is carried out to assess the transient freezing behavior of flowing water inside a pipe cooled from surroundings in consideration of pressure drop caused by the freezing. The finite element technique is applied to solve the equations of motion and energy transport for laminar flow. The numerical model attempts to capture the solid-fluid interface on a fixed computational grid. The correlations among cooling conditions of pipe, velocity and temperature of water at the inlet, and location at which the freezing starts are examined to show the critical velocity to avoid freezing. In addition, under the condition that pressure remains constant at the inlet, the period in which the pipe is not blockaded by ice is calculated. The period is illustrated with some dimensionless parameters to predict the conditions under which blockage occurs within a given time.
NASA Technical Reports Server (NTRS)
Pittman, C. M.; Brinkley, K. L.
1976-01-01
A one-dimensional numerical analysis of the transient thermal response of multilayer insulative systems has been developed. The analysis can determine the temperature distribution through a system consisting of from one to four layers, one of which can be an air gap. Concentrated heat sinks at any interface can be included. The computer program based on the analysis will determine the thickness of a specified layer that will satisfy a temperature limit criterion at any point in the insulative system. The program will also automatically calculate the thickness at several points on a vehicle and determine total system mass.
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
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).
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.
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
GIS Analysis of Size Relationships between Drainage Basins and Alluvial Fans
NASA Astrophysics Data System (ADS)
Wright, S. N.; Scuderi, L. A.; Weissmann, G. S.; Hartley, A. J.
2014-12-01
Imagery from the global database of modern sedimentary basins compiled by Weissman et al. (2010) allows us to test whether a size relationship between drainage basin area and distributive fluvial system (DFS) area exists. We are testing this hypothesis using a combination of SRTM-based digital elevation models and Landsat satellite imagery in ArcGIS. Sedimentary basins are delineated by preforming a Gaussian smoothing on the DEM, followed by optimal edge detection through application of a modified Canny edge detector. The pour points defining the link between contributing hydrologic basins and these sedimentary basins are then located by generating a stream network in ArcGIS and intersecting the stream network arcs with the sedimentary basin polygons. From these pour points we delineate the adjacent contributing drainage basin using the watershed tool in ArcGIS. We manually digitize the boundary and geometry of the DFS identified for each drainage basin, using the higher resolution imagery found on Google Earth for visual confirmation if the scale or resolution of the Landsat imagery requires it. We then extract drainage basins and DFS polygon parameters and calculate areal extents in order to evaluate whether such a size relationship exists within basins, regionally across several basins, or across different basin types (e.g., endorheic vs exhoreic). A limitation of this approach is that we cannot evaluate sediment volumes, only aerial coverage. Results from this study may provide a better understanding of extrabasinal processes that control DFS shape and size.
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
Numerical analysis of specific on-resistance for trench gate superjunction MOSFETs
NASA Astrophysics Data System (ADS)
Onishi, Yasuhiko; Hashimoto, Yoshio
2015-02-01
The numerical analysis results and theoretical limit of specific on-resistance (RON·A) for a parallel trench gate superjunction (SJ) MOSFET where a striped trench gate structure is parallel to a striped SJ structure and a perpendicular trench gate SJ-MOSFET where the striped trench gate structure is perpendicular to the striped SJ structure are presented. Analytical equations for relationships between breakdown voltage and RON·A are verified by device simulation and show good agreement with simulation results. When the MOSFET cell pitch is below half of the SJ pitch, in accordance with the numerical analysis results, the RON·A of the perpendicular SJ-MOSFET is smaller than that of the parallel SJ-MOSFET. This is due to the fact that the drift resistance including a current spreading effect and the channel resistance including a current narrowing effect in the perpendicular SJ-MOSFET are reduced by reducing the MOSFET cell pitch.
A Numerical Analysis on the Local Deformation of a Spacer Grid Structure for Nuclear Fuel Cells
NASA Astrophysics Data System (ADS)
Jang, Myung-Geun; Na, Geum Ju; Shin, Hyunho; Kim, Jong-Bong
2016-08-01
The result of a preliminary numerical investigation on local deformation characteristics of a multi-layered spacer-grid structure with five guide tubes is reported based on implicit finite element analysis. For the numerical analysis, displacements of top and bottom cross sections of each guide tube in a single-layer model were constrained while a lateral displacement was imposed on the single layer. Unlike the impact hammer test that is generally employed to characterize the deformation characteristics of the space-grid structure, the buckling phenomenon occurs locally in this study; it takes place at the inner grids around each tube and the degree of bucking is more apparent for tubes near the lateral surface where the lateral displacement was imposed.
Numerical Analysis of Helicopter Rotor Hovering in Close Proximity to the Ground with a Wall
NASA Astrophysics Data System (ADS)
Itoga, Noriaki; Iboshi, Naohiro; Horimoto, Mitsumasa; Saito, Shigeru; Tanabe, Yasutada
In rescue operations and emergency medical services, helicopters are frequently required to operate near the ground with obstacles such as buildings and sidewalls of highway. In this paper, numerical analysis of helicopter rotor hovering in close proximity to the ground with an obstacle is done by solving unsteady 3D compressible Euler equations with an overlapped grid system. The obstacle is simulated by a wall vertically set up on the ground. The parameters for numerical analysis are the rotor height and distance from the rotor-hub-center to the wall. The effects of combinations of these parameters on the flowfields around the rotor, inflow distributions on the rotor disc and behaviors of blade flapping motion are discussed. It is also clarified the cause that the helicopter rotor hovering in close proximity to the ground with a wall does not have the enough ground effect depending on the combinations of these parameters.
Transient analysis of a pulsed detonation combustor using the numerical propulsion system simulation
NASA Astrophysics Data System (ADS)
Hasler, Anthony Scott
The performance of a hybrid mixed flow turbofan (with detonation tubes installed in the bypass duct) is investigated in this study and compared with a baseline model of a mixed flow turbofan with a standard combustion chamber as a duct burner. Previous studies have shown that pulsed detonation combustors have the potential to be more efficient than standard combustors, but they also present new challenges that must be overcome before they can be utilized. The Numerical Propulsion System Simulation (NPSS) will be used to perform the analysis with a pulsed detonation combustor model based on a numerical simulation done by Endo, Fujiwara, et. al. Three different cases will be run using both models representing a take-off situation, a subsonic cruise and a supersonic cruise situation. Since this study investigates a transient analysis, the pulse detonation combustor is run in a rig setup first and then its pressure and temperature are averaged for the cycle to obtain quasi-steady results.
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
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.
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'.
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 Astrophysics Data System (ADS)
Torrisi, L.; Italiano, A.; Torrisi, A.
2016-11-01
Bronze coins coming from the area of the Mediterranean basin, dated back the II-X Cent. A.D., were analyzed using different physical analytical techniques. Characteristic X-ray fluorescence was used with electrons and photons, in order to investigate the elemental composition of both the surface layers and bulk. Moreover, the quadrupole mass spectrometry coupled to laser ablation (LAMQS technique) in high vacuum was used to analyse typical material compounds from surface contamination. Mass spectrometry, at high resolution and sensitivity, extended up to 300 amu, allowed measuring the 208Pb/206Pb and 207Pb/206Pb isotopic ratios into the coins. Quantitative relative analyses of these isotopic ratios identify the coin composition such as a "fingerprint" depending on the mineral used to extract the lead. Isotopic ratios in coins can be compared to those of the possible minerals used to produce the bronze alloy. A comparison between the measured isotope ratios in the analyzed coins and the literature database, related to the mineral containing Pb as a function of its geological and geophysical extraction mine, is presented. The analysis, restricted to old coins and the mines of the Mediterranean basin, indicates a possible correlation between the coin compositions and the possible geological sites of the extracted mineral.
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.
Numerical Analysis of Flow-Induced Vibrations in Closed Side Branches
NASA Astrophysics Data System (ADS)
KníŽat, Branislav; Troják, Michal
2011-12-01
Vibrations occuring in closed side branches connected to a main pipe are a frequent problem during pipeline system operation. At the design stage of pipeline systems, this problem is sometimes overlooked or underestimated which can later lead to the shortening of the systems life cycle or may even cause injury. The aim of this paper is a numerical analysis of the start of self-induced vibrations on the edge of a closed side branch. Calculation conditions and obtained results are presented within.
Analysis of CO2 emission in traffic flow and numerical tests
NASA Astrophysics Data System (ADS)
Zhu, Wen-Xing
2013-10-01
We investigated the carbon dioxide emission rate in traffic flow analytically and numerically. The emission model was derived based on Bando’s optimal velocity model with a consideration of slope. Simulations were conducted to examine the relationship between the CO2 emission rate of vehicles and slope of road, traffic density, and road length. Analysis of the results shows that some original laws of CO2 emission in traffic flow with congestion were exhibited.
NASA Astrophysics Data System (ADS)
Cherepanov, Roman O.; Cherepanov, Oleg I.; Krektuleva, Raisa A.
2015-10-01
This paper proposes a wavelet based numerical method for the solution of elastoplastic problem. The method is based on the Lagrange variational equation of elastic static and the Haar wavelet transform of the components of deformation field. Some examples of analysis of multilevel deformation are shown for the demonstration of the method's capabilities. Some differences in the wavelet spectrums of multilevel inhomogeneous media are shown and discussed.
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.
NASA Astrophysics Data System (ADS)
Beaudoin, N.; Bellahsen, N.; Lacombe, O.; Emmanuel, L.; Pironon, J.
2012-04-01
While fluid flows associated with thin-skinned folded structures have been extensively studied, reconstructions of paleofluid systems associated with thick-skinned tectonics remain scarce. In addition, major thrusts are usually considered as the preferential channels for fluids: investigating the role of diffuse fracture sets as potential drains for fluids has received poor attention. In this work, we tentatively reconstruct the paleofluid system related to the Bighorn basin (Wyoming, USA), a Sevier-Laramide foreland basin affected by large basement uplifts during the Laramide thick-skinned tectonic event. Fracture pattern and related paleofluid flow were studied in selected folds within this basin. For this purpose, Oxygen, Carbon and Strontium isotopic studies were performed on host rocks as well as on pre-folding and on fold-related calcite veins; these studies were combined to fluid inclusion chemical and microthermometric analysis. The results suggest a strong control of fluid chemistry by the tectonic style: our work evidences migration of exotic hydrothermal fluids (temperatures of homogenisation of fluid inclusion reaching 140°C) in basement-cored, thrust-related folds, while in detachment folds, only intra-formational fluids were characterized.At the scale of the entire basin, the open paleofluid system reconstructed in basement-cored folds appears to be consistent, with oxygen isotopic signature ranging from -25‰ to -5‰ PDB. Indeed, the scattering of oxygen isotopic signatures in cemented veins shows different degree of mixing between local basinal fluids and exotic hydrothermal fluids remaining unequilibrated with surrounding limestones. Strontium isotopic analyses suggest that these exotic hydrothermal fluids are a mixing of meteoric fluids and basinal fluids that havemigrated in basement rocks, likely deeper than the basement/cover interface. The timing of the fast upward flow of these fluids through the cover is given by, and related to
NASA Astrophysics Data System (ADS)
Sohn, Jeong L.
1988-08-01
The purpose of the study is the evaluation of the numerical accuracy of FIDAP (Fluid Dynamics Analysis Package). Accordingly, four test problems in laminar and turbulent incompressible flows are selected and the computational results of these problems compared with other numerical solutions and/or experimental data. These problems include: (1) 2-D laminar flow inside a wall-driven cavity; (2) 2-D laminar flow over a backward-facing step; (3) 2-D turbulent flow over a backward-facing step; and (4) 2-D turbulent flow through a turn-around duct.
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
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
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.
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.
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.
Impact of Entropy Generation on Stagnation-Point Flow of Sutterby Nanofluid: A Numerical Analysis
NASA Astrophysics Data System (ADS)
Azhar, Ehtsham; Iqbal, Z.; Maraj, E. N.
2016-09-01
The present article dicusses the computational analysis of entropy generation for the stagnation-point flow of Sutterby nanofluid over a linear stretching plate. The Sutterby fluid is chosen to study the effect for three major classes of non-Newtonian fluids, i.e. pseudoplastic, Newtonian, and dilatant. The effects of pertinent physical parameters are examined under the approximation of boundary layer. The system of coupled nonlinear partial differential equations is simplified by incorporating suitable similarity transformation into a system of non-linear-coupled ordinary differential equations. Entropy generation analysis is conducted numerically, and the results are displayed through graphs and tables. Significant findings are listed in the closing remarks.
Finite strip method combined with other numerical methods for the analysis of plates
NASA Astrophysics Data System (ADS)
Cheung, M. S.; Li, Wenchang
1992-09-01
Finite plate strips are combined with finite elements or boundary elements in the analysis of rectangular plates with some minor irregularities such as openings, skew edges, etc. The plate is divided into regular and irregular regions. The regular region is analyzed by the finite strip method while the irregular one is analyzed by the finite element or boundary element method. A special transition element and strip are developed in order to connect the both regions. Numerical examples will show the accuracy and efficiency of this combined analysis.
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.
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
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.
Preisig, Giona; Cornaton, Fabien Joel; Perrochet, Pierre
2014-01-01
Changes in effective stress due to water pressure variations modify the intrinsic hydrodynamic properties of aquifers and aquitards. Overexploited groundwater systems, such as basins with heavy pumping, are subject to nonrecoverable modifications. This results in loss of permeability, porosity, and specific storage due to system consolidation. This paper presents (1) the analytical development of model functions relating effective stress to hydrodynamic parameters for aquifers and aquitards constituted of unconsolidated granular sediments, and (2) a modeling approach for the analysis of aquifer systems affected by effective stress variations, taking into account the aforementioned dependency. The stress-dependent functions were fit to laboratory data, and used in the suggested modeling approach. Based on only few unknowns, this approach is computationally simple, efficiently captures the hydromechanical processes that are active in regional aquifer systems under stress, and readily provides an estimate of their consolidation. PMID:23448260
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.
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
Three Dimensional Analysis of Fault Interaction along a Simple Pull-Apart Basin
NASA Astrophysics Data System (ADS)
Sagy, A.; Hamiel, Y.
2015-12-01
Pull-apart basins reflect basic interaction between two faults and have been studied in detail during the last decades. However, the true three-dimensional geometry of pull-apart basins is seldom known. We therefore present a new study focused on the architecture of a pull-apart basin and the associated stresses. We analyze the structure of a ~250 m long pull-apart basin developed in carbonate rocks at the Galilee heights, Israel. The reconstruction of the basin geometry is based on detailed mapping and LiDAR measurements of fault scarps. The architecture of faults is then used as a boundary condition for calculating the stress pattern in the vicinity of the basin, using a dislocation model. The basin is found to be an asymmetrical structure bordered by two longitudinal oblique right lateral strike-slip faults. The strike of one of the faults is bent at the eastern edge of the basin, generating a transverse boundary fault which joins the second boundary fault orthogonally. The overall lateral displacement is smaller than the basin length and no transverse or diagonal fault is observed in the western end of the basin. The deformation around the basin is mostly displayed by fractures. Yet, folds and fault branches are observed near the tips of the boundary faults and near kink points of fault segments. We found that the interaction of the two subparallel strike-slip segments observed in the outcrop is expressed by a V-shaped basin structure. Therefore, a subsurface bending in the main fault is expressed by step-over and by subsidence close to the upper surface. The geometry of the basin deviates from the typical rhomb shape even in map view, as the basin is not bordered by transverse or diagonal faults on its western edge. The lateral displacement along the basin is localized on oblique bordering strike-slip faults with less slip partitioning than observed in larger pull-apart basins. 3D modeling of the stress field around the basin demonstrated that the pull
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.
The numerical analysis of the rotational theory for the formation of lunar globules
NASA Technical Reports Server (NTRS)
Ross, J.; Bastin, J.; Stewart, K.
1982-01-01
The morphology of lunar globules is studied through the application of a numerical analysis of their rotation in space during cooling. It is assumed that molten rock is shot from the surface of the moon, solidifies in space above the moon and then falls back to the surface. The rotational theory studied makes the following assumptions: the volume of the molten rock does not change during cooling; the angular momentum is conserved; there are no internal motions because of the high viscosity of the molten rock, i.e., in equilibrium the globule is rotating as a rigid body; finally, the kinetic reaction of the globule to the forces is fast relative to the rate of cooling, i.e., the globule reaches equilibrium at constant energy. These assumptions are subjected to numerical analysis yielding good agreement between the actual globule shapes and the numerical results, but leaving some doubt as to the validity of the rotational theory due to the failure to establish the existence of true local minima and an incomplete understanding of the thermokentics.
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.
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.
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
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 for Optimal Design of Fin and Tube Type Adsorber
NASA Astrophysics Data System (ADS)
Kariya, Keishi; Kuwahara, Ken; Shigeru, Koyama
Adsorption cooling systems driven by low temperature waste heat (below 100°C) or renewable energy sources have gained considerable attention as one of the solutions for both energy and environment related problems. In this study, a two dimensional numerical analysis is carried out to evaluate the adsorption characteristics and to determine the performance of a fin and tube type adsorber/desorber heat exchanger; activated carbon fiber (ACF) of type A-20, which has relatively higher surface area, and ethanol are used as adsorbent/refrigerant pair. The effects of heat exchanger design configurations such as fin height, fin thickness, fin pitch, tube diameter and apparent density of ACF bed on the performance are examined numerically. The simulation results show that the cooling capacity can be optimized in the condition of fin height 15mm and fin pitch 5.5mm when other parameters are fixed.
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.
Kabala, Z.J.; Milly, P.C.D. )
1990-04-01
Sensitivity analysis is one of the tools available for analyzing the effects of parameter uncertainty and soil heterogeneity on the transport of moisture in the unsaturated similar porous media. Direct differentiation of the discretized Richards equation with respect to parameters defining spatial variability leads to linear systems of equations for elementary sensitivities that are readily solved in conjunction with the original equation. These elementary sensitivities can be easily transformed into approximations of functional sensitivities and into sensitivities of boundary fluxes. A numerical implementation of this technique in one space dimension yields results that are consistent with exact analytical solutions and with numerical perturbation calculations. The effects of a given heterogeneity can be modeled adequately provided that the maximum relative change of the scale factor from one grid to the next not exceed a number on the order of unity.
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.
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.
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)
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
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.
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.
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.
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.
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
Linear stability analysis and direct numerical simulation of a miscible two-fluid channel flow
NASA Astrophysics Data System (ADS)
Haapanen, Siina Ilona
The temporal evolution of an initially laminar two-fluid channel flow is investigated using linear stability analysis and direct numerical simulation. The stability of a two-fluid shear flow is encountered in numerous situations, including water wave generation by wind, atomization of fuels, aircraft deicing and nuclear reactor cooling. The application of particular interest in this study is liquefying hybrid combustion, for which the two-fluid channel flow is used as a model problem to characterize the relevant mixing and entrainment mechanisms. The two fluids are miscible with dissimilar densities and viscosities. The thickness of one of the fluid layers is much smaller than that of the other, with the denser and more viscous fluid comprising the thin layer. Linear stability analysis is used to identify possibly unstable modes in the two-fluid configuration. The analysis is considered for two different situations. In one case, the fluid density and viscosity change discontinuously across a sharp interface, while in the other, the fluids are separated by a finite thickness transition layer, over which the fluid properties vary continuously. In the sharp interface limit, the linear stability is governed by an Orr-Sommerfeld equation in each fluid layer, coupled by boundary conditions at the interface. A numerical solution of the system of equations is performed using a Chebyshev spectral collocation method. In the case where the fluids are separated by a finite thickness transition zone, an Orr-Sommerfeld-type equation is solved with the compound matrix method. The non-linear stages of the flow evolution are investigated by direct numerical simulation. In a temporal simulation, two of the three spatial dimensions are periodic. Fourier spectral discretization is used in these dimensions, while a compact finite difference scheme is utilized in the non-periodic direction. The time advancement is performed by a projection method with a third order Adams
Kondig, John P; Turell, Michael J; Lee, John S; O'Guinn, Monica L; Wasieloski, Leonard P
2007-03-01
Identifying viral isolates from field-collected mosquitoes can be difficult and time-consuming, particularly in regions of the world where numerous closely related viruses are co-circulating (e.g., the Amazon Basin region of Peru). The use of molecular techniques may provide rapid and efficient methods for identifying these viruses in the laboratory. Therefore, we determined the complete nucleotide sequence of two South American eastern equine encephalomyelitis viruses (EEEVs): one member from the Peru-Brazil (Lineage II) clade and one member from the Argentina-Panama (Lineage III) clade. In addition, we determined the nucleotide sequence for the nonstructural P3 protein (nsP3) and envelope 2 (E2) protein genes of 36 additional isolates of EEEV from mosquitoes captured in Peru between 1996 and 2001. The 38 isolates were evenly distributed between lineages II and III virus groupings. However, analysis of the nsP3 gene for lineage III strongly suggested that the 19 isolates from this lineage could be divided into two sub-clades, designated as lineages III and IIIA. Compared with North American EEEV (lineage I, GA97 strain), we found that the length of the nsP3 gene was shorter in the strains isolated from South America. A total of 60 nucleotides was deleted in lineage II, 69 in lineage III, and 72 in lineage IIIA. On the basis of the sequences we determined for South American EEEVs and those for other viruses detected in the same area, we developed a series of primers for characterizing these viruses.
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
Stone, M.A.; Parliman, D.J.; Schaefer, J.L.
1996-01-01
The U.S. Geological Survey began a regional aquifer-system analysis of the Northern Rocky Mountains of northern and central Idaho and western Montana in 1990. The analysis helped establish a regional framework of information for aquifers in about 70 ntermontane basins in an area of 80,000 square miles. In many areas, ground water is the only suitable source of supply, yet little information is available about this resource. Selected geohydrologic data from 1,004 wells in 19 intermontane basins in Idaho were compiled as part of the regional analysis. Data consist of basin name and well number, altitude of land surface, date of well construction, geologic unit, depth of well, diameter of casing, type of finish, top of open interval, primary use of water, date of water level measurement, water level, discharge, specific capacity, source of discharge data, type of log available, date of water-quality constituent measurement, specific conductance, pH, and temperature. A similar report for intermontane basins in Montana has been published by the U.S. Geologcial Survey in Montana. (USGS)
Numerical continuation and bifurcation analysis in aircraft design: an industrial perspective.
Sharma, Sanjiv; Coetzee, Etienne B; Lowenberg, Mark H; Neild, Simon A; Krauskopf, Bernd
2015-09-28
Bifurcation analysis is a powerful method for studying the steady-state nonlinear dynamics of systems. Software tools exist for the numerical continuation of steady-state solutions as parameters of the system are varied. These tools make it possible to generate 'maps of solutions' in an efficient way that provide valuable insight into the overall dynamic behaviour of a system and potentially to influence the design process. While this approach has been employed in the military aircraft control community to understand the effectiveness of controllers, the use of bifurcation analysis in the wider aircraft industry is yet limited. This paper reports progress on how bifurcation analysis can play a role as part of the design process for passenger aircraft.
Numerical continuation and bifurcation analysis in aircraft design: an industrial perspective.
Sharma, Sanjiv; Coetzee, Etienne B; Lowenberg, Mark H; Neild, Simon A; Krauskopf, Bernd
2015-09-28
Bifurcation analysis is a powerful method for studying the steady-state nonlinear dynamics of systems. Software tools exist for the numerical continuation of steady-state solutions as parameters of the system are varied. These tools make it possible to generate 'maps of solutions' in an efficient way that provide valuable insight into the overall dynamic behaviour of a system and potentially to influence the design process. While this approach has been employed in the military aircraft control community to understand the effectiveness of controllers, the use of bifurcation analysis in the wider aircraft industry is yet limited. This paper reports progress on how bifurcation analysis can play a role as part of the design process for passenger aircraft. PMID:26303915
Coupled numerical analysis to investigate the heating mechanism of ultrasonic imprint lithography.
Park, Jong Han; Lee, Ki Yeon; Park, Keun
2015-07-01
Ultrasonic imprint lithography (UIL) is a micropattern replication technology on thermoplastic polymers using ultrasonic vibration energy. The UIL process involves three steps: (i) microscale vibration from an ultrasonic horn causes repetitive deformation of a polymer surface, (ii) the polymer surface is locally softened by repetitive deformation and friction, and (iii) micro/nanoscale patterns engraved on the horn or the mold are replicated on the softened substrate. To replicate micro/nano patterns with high accuracy, the effects of various processing conditions should be investigated, and so far, these have been studied experimentally. In this study, coupled numerical analysis was performed using finite element simulation to investigate the heating mechanism of the UIL process, by joining transient structural analysis and heat transfer analysis. The effect of imprinting conditions on the heating capability was investigated using the proposed coupled simulation. The differences between direct and indirect imprinting are also discussed in terms of heating mechanism, and compared with experiments.
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
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)
Hydrologic properties of coal beds in the Powder River Basin, Montana I. Geophysical log analysis
Morin, R.H.
2005-01-01
As part of a multidisciplinary investigation designed to assess the implications of coal-bed methane development on water resources for the Powder River Basin of southeastern Montana, six wells were drilled through Paleocene-age coal beds along a 31-km east-west transect within the Tongue River drainage basin. Analysis of geophysical logs obtained in these wells provides insight into the hydrostratigraphic characteristics of the coal and interbedded siliciclastic rocks and their possible interaction with the local stress field. Natural gamma and electrical resistivity logs were effective in distinguishing individual coal beds. Full-waveform sonic logs were used to determine elastic properties of the coal and an attendant estimate of aquifer storage is in reasonable agreement with that computed from a pumping test. Inspection of magnetically oriented images of the borehole walls generated from both acoustic and optical televiewers and comparison with coal cores infer a face cleat orientation of approximately N33??E, in close agreement with regional lineament patterns and the northeast trend of the nearby Tongue River. The local tectonic stress field in this physiographic province as inferred from a nearby 1984 earthquake denotes an oblique strike-slip faulting regime with dominant east-west compression and north-south extension. These stress directions are coincident with those of the primary fracture sets identified from the televiewer logs and also with the principle axes of the drawdown ellipse produced from a complementary aquifer test, but oblique to apparent cleat orientation. Consequently, examination of these geophysical logs within the context of local hydrologic characteristics indicates that transverse transmissivity anisotropy in these coals is predominantly controlled by bedding configuration and perhaps a mechanical response to the contemporary stress field rather than solely by cleat structure.
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)
Castaldo, R.; Tizzani, P.; Lollino, P.; Calò, F.; Ardizzone, F.; Lanari, R.; Guzzetti, F.; Manunta, M.
2015-11-01
The aim of this paper is to propose a methodology to perform inverse numerical modelling of slow landslides that combines the potentialities of both numerical approaches and well-known remote-sensing satellite techniques. In particular, through an optimization procedure based on a genetic algorithm, we minimize, with respect to a proper penalty function, the difference between the modelled displacement field and differential synthetic aperture radar interferometry (DInSAR) deformation time series. The proposed methodology allows us to automatically search for the physical parameters that characterize the landslide behaviour. To validate the presented approach, we focus our analysis on the slow Ivancich landslide (Assisi, central Italy). The kinematical evolution of the unstable slope is investigated via long-term DInSAR analysis, by exploiting about 20 years of ERS-1/2 and ENVISAT satellite acquisitions. The landslide is driven by the presence of a shear band, whose behaviour is simulated through a two-dimensional time-dependent finite element model, in two different physical scenarios, i.e. Newtonian viscous flow and a deviatoric creep model. Comparison between the model results and DInSAR measurements reveals that the deviatoric creep model is more suitable to describe the kinematical evolution of the landslide. This finding is also confirmed by comparing the model results with the available independent inclinometer measurements. Our analysis emphasizes that integration of different data, within inverse numerical models, allows deep investigation of the kinematical behaviour of slow active landslides and discrimination of the driving forces that govern their deformation processes.
NASA Astrophysics Data System (ADS)
Brunetti, J.; Massi, F.; Saulot, A.; Renouf, M.; D`Ambrogio, W.
2015-06-01
Mechanical systems present several contact surfaces between deformable bodies. The contact interface can be either static (joints) or in sliding (active interfaces). The sliding interfaces can have several roles and according to their application they can be developed either for maximizing the friction coefficient and the energy dissipation (e.g. brakes) or rather to allow the relative displacement at joints with a maximum efficiency. In both cases the coupling between system and local contact dynamics can bring to system dynamics instabilities (e.g. brake squeal or squeaking of hip prostheses). This results in unstable vibrations of the system, induced by the oscillation of the contact forces. In the literature, a large number of works deal with such kind of instabilities and are mainly focused on applied problems such as brake squeal noise. This paper shows a more general numerical analysis of a simple system constituted by two bodies in sliding contact: a rigid cylinder rotating inside a deformable one. The parametrical Complex Eigenvalue Analysis and the transient numerical simulations show how the friction forces can give rise to in-plane dynamic instabilities due to the interaction between two system modes, even for such a simple system characterized by one deformable body. Results from transient simulations highlight the key role of realistic values of the material damping to have convergence of the model and, consequently, reliable physical results. To this aim an experimental estimation of the material damping has been carried out. Moreover, the simplicity of the system allows for a deeper analysis of the contact instability and a balance of the energy flux among friction, system vibrations and damping. The numerical results have been validated by comparison with experimental ones, obtained by a specific test bench developed to reproduce and analyze the contact friction instabilities.
NASA Astrophysics Data System (ADS)
Crow, W.; Gasda, S. E.; Williams, D. B.; Celia, M. A.; Carey, J. W.
2008-12-01
An important aspect of the risk associated with geological CO2 sequestration is the integrity of existing wellbores that penetrate geological layers targeted for CO2 injection. CO2 leakage may occur through multiple pathways along a wellbore, including through micro-fractures and micro-annuli within the "disturbed zone" surrounding the well casing. The effective permeability of this zone is a key parameter of wellbore integrity required for validation of numerical models. This parameter depends on a number of complex factors, including long-term attack by aggressive fluids, poor well completion and actions related to production of fluids through the wellbore. Recent studies have sought to replicate downhole conditions in the laboratory to identify the mechanisms and rates at which cement deterioration occurs. However, field tests are essential to understanding the in situ leakage properties of the millions of wells that exist in the mature sedimentary basins in North America. In this study, we present results from a field study of a 30-year-old production well from a natural CO2 reservoir. The wellbore was potentially exposed to a 96% CO2 fluid from the time of cement placement, and therefore cement degradation may be a significant factor leading to leakage pathways along this wellbore. A series of downhole tests was performed, including bond logs and extraction of sidewall cores. The cores were analyzed in the laboratory for mineralogical and hydrologic properties. A pressure test was conducted over an 11-ft section of well to determine the extent of hydraulic communication along the exterior of the well casing. Through analysis of this pressure test data, we are able estimate the effective permeability of the disturbed zone along the exterior of wellbore over this 11-ft section. We find the estimated range of effective permeability from the field test is consistent with laboratory analysis and bond log data. The cement interfaces with casing and/or formation are
NASA Astrophysics Data System (ADS)
Rivola, Alessandro; Troncossi, Marco
2014-10-01
The development of high-performance vehicle engines requires advanced investigations in order to provide engineers with proper analysis tools to optimize the system design. The elastodynamic behaviour of the engine powertrain may be critical at high velocities (when the flexibility of the system components can have a major role on the overall performance) with consequences on the valve timing and the transmission of dynamic loads. A thorough numerical/experimental investigation was performed on the timing system of a racing motorbike engine. The timing system included the geartrain, which transmits power from the crankshaft to the camshafts, and the valve train, formed by the camshafts and the cam-follower mechanisms for the valve actuation. An experimental campaign was designed and carried out with the purpose of inspecting the timing system behaviour for different velocities and different design parameters. A numerical model was developed in order to provide a simulation/analysis tool that permits the design optimization of the main system components. The present work focuses on the geartrain elastodynamic analysis, which is the main novelty of a long-lasting activity carried out by the authors in collaborations with Ducati Motor Holding S.p.a. (Bologna, Italy). The experimental campaign, the model development and validation, and some simulation results are reported and discussed.
Exploring the tecto-sedimentary history of the lower Kumano basin: insights from 3D seismic analysis
NASA Astrophysics Data System (ADS)
Ramirez, S. G.; Gulick, S. P.; Hayman, N. W.
2013-12-01
The Nankai accretionary margin is seismically active, representing a hazard for the people living along the southwestern Japanese shores. In an effort to better understand its behavior, 3D seismic and well data have been acquired in the area. We are using such data in order to address open research topics such as: the conditions for forearc basin initiation, the role of former slope basins and slope cover sediments in the formation of forearc basins and the role of changes in sedimentation as a major controlling factor in forearc basin evolution. New 3D maps of key surfaces that bound and lie within the lower Kumano basin help us illuminate these topics. The lower bounding surface, UC4, represents missing section between 5.6-3.8 Ma. Toward the SE UC4 is relatively undeformed, with some structures approximately parallel to the modern-day trench. In contrast, toward the NW UC4 is intensely deformed with two main synforms whose hinges are oriented 15 degrees to the modern-trench. The two synforms have similar wavelengths and amplitudes and define the thickest sediment accumulations in the lower Kumano basin. We hypothesize that UC4 had a protracted evolution with early synform (thrust-bound slope-basins?) followed by a change in the maximum strain/plate convergence direction. This change caused the structural trend observed to the SE. This interpretation is in agreement with previous independent estimations of block rotation based on paleomagnetic analysis of samples from core recovered in the area. The upper bounding surface of the lower Kumano basin, UC2, underlies 1.6 Ma and younger sediments. Its morphology resembles a much smoother and less deformed version of UC4. It is slightly tilted landward. Seaward, it pinches out against UC4. Between the two bounding surfaces we recognized a major unconformity that we called UC3a and that we were able to track through most of the studied part of the seismic volume. Morphologically, UC3a is very similar to UC2. We interpret
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.
Kwon, T.H.; Kim, C.S.
1995-07-01
A numerical modeling is proposed for the simulation of flow, heat transfer, and reaction kinetics during the compression molding of three-dimensional thin parts. A nonisothermal, non-Newtonian model including the kinetic equation for a curing mechanism of thermosetting materials is implemented in a computer program, and a finite element method is used to simulate a preheating, a filling, and a post-heating stage during the entire compression molding process. As a more rigorous approach, a moving boundary condition due to the drag motion of an upper mold of a nonplanar shape or due to an apparent slip phenomena of particle filled materials is introduced into the present modeling, resulting in a new governing equation and the corresponding finite element formulation. Verifications of the analysis program were performed with a simple geometry for the Newtonian and non-Newtonian isothermal cases, in which the numerical results are found to be in good agreement with theoretical results. Effects of the moving boundary condition and processing conditions, such as thickness of compression molded parts, mold closing velocity and the preheating stage on overall compression molding processing, are numerically investigated.
Numerical analysis of water and solute transport in variably-saturated fractured clayey till.
Rosenbom, Annette E; Therrien, Rene; Refsgaard, Jens Christian; Jensen, Karsten H; Ernstsen, Vibeke; Klint, Knud Erik S
2009-02-16
This study numerically investigates the influence of initial water content and rain intensities on the preferential migration of two fluorescent tracers, Acid Yellow 7 (AY7) and Sulforhodamine B (SB), through variably-saturated fractured clayey till. The simulations are based on the numerical model HydroGeoSphere, which solves 3D variably-saturated flow and solute transport in discretely-fractured porous media. Using detailed knowledge of the matrix, fracture, and biopore properties, the numerical model is calibrated and validated against experimental high-resolution tracer images/data collected under dry and wet soil conditions and for three different rain events. The model could reproduce reasonably well the observed preferential migration of AY7 and SB through the fractured till, although it did not capture the exact depth of migration and the negligible impact of the dead-end biopores in a near-saturated matrix. A sensitivity analysis suggests fast flow mechanisms and dynamic surface coating in the biopores, and the presence of a plough pan in the till.
Analysis of the variability of the axial dipole moment of a numerical geodynamo model
NASA Astrophysics Data System (ADS)
Kuipers, J.; Hoyng, P.; Wicht, J.; Barkema, G. T.
2009-04-01
We have analysed the time evolution of the axial dipole moments (ADMs) from three numerical geodynamo models by relating it to the Fokker-Planck equation governing the systematic and random ADM motion. We have determined the effective growth rate of the ADM and the diffusion coefficient D characterising its random fluctuations. We find that the numerical ADM data exhibit a nonlinear quenching that is not significantly different from that of the Sint-2000 data. The quenching is only partly due to a reduction of the r.m.s. convective flow speed with increasing ADM. Our results suggest that in these numerical models similar mechanisms may be at work as in the earth's core, and that the results of Brendel et al. [Brendel, K., Kuipers, J., Barkema, G.T., Hoyng, P., 2007. An analysis of the fluctuations of the geomagnetic dipole. Phys. Earth Planet. Inter. 162, 249-255] are unlikely to be an artifact caused by the restricted length of the dataset. They also suggest that the dynamics of the ADM is that of a Brownian particle (i.e. driven by additive noise) in a bistable potential, and we illustrate some consequences of this idea.
NASA Technical Reports Server (NTRS)
Coppolino, R. N.
1974-01-01
Details are presented of the implementation of the new formulation into NASTRAN including descriptions of the DMAP statements required for conversion of the program and details pertaining to problem definition and bulk data considerations. Details of the current 1/8-scale space shuttle external tank mathematical model, numerical results and analysis/test comparisons are also presented. The appendices include a description and listing of a FORTRAN program used to develop harmonic transformation bulk data (multipoint constraint statements) and sample bulk data information for a number of hydroelastic problems.
Ben Gur, Hila; Kosa, Gabor; Brand, Moshe
2015-08-01
This paper presents a numerical analysis of the hemodynamics in an abdominal aorta (AA) with an aneurysm repaired by a stent graft (SG) system using the chimney technique. Computational fluid dynamics (CFD) simulations were conducted in a model of an AA repaired with a chimney stent graft (CSG) inserted into a renal artery parallel to an aortic SG and a model of a healthy AA. Comparing the simulation results of these two cases suggests that the presence of the CSG in the AA causes changes in average wall shear stress (WSS), potentially damaging recirculation zones, and additional changes in flow patterns. PMID:26736427
Trousson, P.; Lion, Y.
1985-05-09
A study of long-range proton coupling in nitroxide radicals has been performed with a numerical analysis program using the Fourier transform technique. The present method provides a means for further identification of radicals which is particularly useful for species that are otherwise indistinguishable. The superhyperfine structure of piperidine and pyrrolidine-1-oxyl derivatives, showing ..gamma..-nuclei coupling constants as small as 0.2 G, has been brought out. The results are in good agreement with those obtained by other resolution-enhancement methods. 17 references, 7 figures, 3 tables.
A Numerical Analysis of the Resistance and Stiffness of the Aluminium and Concrete Composite Beam
NASA Astrophysics Data System (ADS)
Polus, Łukasz; Szumigała, Maciej
2015-03-01
In this paper a numerical analysis of the resistance and stiffness of the aluminium and concrete composite beam is presented. Composite aluminium and concrete structures are quite new and they have not been thoroughly tested. Composite structures have a lot of advantages. The composite aluminium and concrete beam is more corrosion-resistant, fire-resistant and stiff than the aluminium beam. The contemporary idea of sustainable buildings relies on new solutions which are more environmentally friendly. Aluminium is lighter and more resistant to corrosion than steel, which is often used in composite structures.
Hofland, G.S.; Barton, C.C.
1990-10-01
The computer program FREQFIT is designed to perform regression and statistical chi-squared goodness of fit analysis on one-dimensional or two-dimensional data. The program features an interactive user dialogue, numerous help messages, an option for screen or line printer output, and the flexibility to use practically any commercially available graphics package to create plots of the program`s results. FREQFIT is written in Microsoft QuickBASIC, for IBM-PC compatible computers. A listing of the QuickBASIC source code for the FREQFIT program, a user manual, and sample input data, output, and plots are included. 6 refs., 1 fig.
Error analysis of numerical gravitational waveforms from coalescing binary black holes
NASA Astrophysics Data System (ADS)
Fong, Heather; Chu, Tony; Kumar, Prayush; Pfeiffer, Harald; Boyle, Michael; Hemberger, Daniel; Kidder, Lawrence; Scheel, Mark; Szilagyi, Bela; SXS Collaboration
2016-03-01
The Advanced Laser Interferometer Gravitational-wave Observatory (Advanced LIGO) has finished a successful first observation run and will commence its second run this summer. Detection of compact object binaries utilizes matched-filtering, which requires a vast collection of highly accurate gravitational waveforms. This talk will present a set of about 100 new aligned-spin binary black hole simulations. I will discuss their properties, including a detailed error analysis, which demonstrates that the numerical waveforms are sufficiently accurate for gravitational wave detection purposes, as well as for parameter estimation purposes.
Peters, J.G.
1987-01-01
The Indiana Department of Natural Resources (IDNR) is developing water-management policies designed to assess the effects of irrigation and other water uses on water supply in the basin. In support of this effort, the USGS, in cooperation with IDNR, began a study to evaluate appropriate methods for analyzing the effects of pumping on ground-water levels and streamflow in the basin 's glacial aquifer systems. Four analytical models describe drawdown for a nonleaky, confined aquifer and fully penetrating well; a leaky, confined aquifer and fully penetrating well; a leaky, confined aquifer and partially penetrating well; and an unconfined aquifer and partially penetrating well. Analytical equations, simplifying assumptions, and methods of application are described for each model. In addition to these four models, several other analytical models were used to predict the effects of ground-water pumping on water levels in the aquifer and on streamflow in local areas with up to two pumping wells. Analytical models for a variety of other hydrogeologic conditions are cited. A digital ground-water flow model was used to describe how a numerical model can be applied to a glacial aquifer system. The numerical model was used to predict the effects of six pumping plans in 46.5 sq mi area with as many as 150 wells. Water budgets for the six pumping plans were used to estimate the effect of pumping on streamflow reduction. Results of the analytical and numerical models indicate that, in general, the glacial aquifers in the basin are highly permeable. Radial hydraulic conductivity calculated by the analytical models ranged from 280 to 600 ft/day, compared to 210 and 360 ft/day used in the numerical model. Maximum seasonal pumping for irrigation produced maximum calculated drawdown of only one-fourth of available drawdown and reduced streamflow by as much as 21%. Analytical models are useful in estimating aquifer properties and predicting local effects of pumping in areas with
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
Temporal scaling analysis of irradiance estimated from daily satellite data and numerical modelling
NASA Astrophysics Data System (ADS)
Vindel, Jose M.; Navarro, Ana A.; Valenzuela, Rita X.; Ramírez, Lourdes
2016-11-01
The temporal variability of global irradiance estimated from daily satellite data and numerical models has been compared for different spans of time. According to the time scale considered, a different behaviour can be expected for each climate. Indeed, for all climates and at small scale, the persistence decreases as this scale increases, but the mediterranean climate, and its continental variety, shows higher persistence than oceanic climate. The probabilities of maintaining the values of irradiance after a certain period of time have been used as a first approximation to analyse the quality of each source, according to the climate. In addition, probability distributions corresponding to variations of clearness indices measured at several stations located in different climate zones have been compared with those obtained from satellite and modelling estimations. For this work, daily radiation data from the reanalysis carried out by the European Centre for Medium-Range Weather Forecasts and from the Satellite Application Facilities on climate monitoring have been used for mainland Spain. According to the results, the temporal series estimation of irradiance is more accurate when using satellite data, independent of the climate considered. In fact, the coefficients of determination corresponding to the locations studied are always above 0.92 in the case of satellite data, while this coefficient decreases to 0.69 for some cases of the numerical model. This conclusion is more evident in oceanic climates, where the most important errors can be observed. Indeed, in this case, the RRMSE derived from the CM-SAF estimations is 20.93%, while in the numerical model, it is 48.33%. Analysis of the probabilities corresponding to variations in the clearness indices also shows a better behaviour of the satellite-derived estimates for oceanic climate. For the standard mediterranean climate, the satellite also provides better results, though the numerical model improves
NASA Astrophysics Data System (ADS)
Rasmussen, Robert Gary
Several topics relating to the objective analysis of humidity for regional scale numerical weather prediction are investigated. These include: (1) sampling the humidity field; (2) choosing an analysis scheme; (3) choosing an analysis variable; (4) using surface data to diagnose upper -air humidity (SFC-DIAG); (5) using cloud analysis data to diagnose surface and upper-air humidities (3DNEPH-DIAG); and (6) modeling the humidity lateral autocorrelation function. Regression equations for the diagnosed humidities and several correlation models are developed and validated. Four types of data are used in a preliminary demonstration: observations (radiosonde and surface), SFC-DIAG data, 3DNEPH-DIAG data, and forecast data from the Drexel/NCAR Limited-Area and Mesoscale Prediction System (LAMPS). The major conclusions are: (1) independent samples of relative humidity can be obtained by sampling at intervals of two days and 1750 km, on the average; (2) Gandin's optimum interpolation (OI) is preferable to Cressman's successive correction and Panofsky's surface fitting schemes; (3) relative humidity (RH) is a better analysis variable than dew-point depression; (4) RH*, the square root of (1-RH), is better than RH; (5) both surface and cloud analysis data can be used to diagnose the upper-air humidity; (6) pooling dense data prior to OI analysis can improve the quality of the analysis and reduce its computational burden; (7) iteratively pooling data is economical; (8) for the types of data considered, use of more than about eight data in an OI point analysis cannot be justified by expectations of further reducing the analysis error variance; and (9) the statistical model in OI is faulty in that an analyzed humidity can be biased too much toward the first guess.
NASA Technical Reports Server (NTRS)
Lacasse, James M.
1995-01-01
A multiblock sensitivity analysis method is applied in a numerical aerodynamic shape optimization technique. The Sensitivity Analysis Domain Decomposition (SADD) scheme which is implemented in this study was developed to reduce the computer memory requirements resulting from the aerodynamic sensitivity analysis equations. Discrete sensitivity analysis offers the ability to compute quasi-analytical derivatives in a more efficient manner than traditional finite-difference methods, which tend to be computationally expensive and prone to inaccuracies. The direct optimization procedure couples CFD analysis based on the two-dimensional thin-layer Navier-Stokes equations with a gradient-based numerical optimization technique. The linking mechanism is the sensitivity equation derived from the CFD discretized flow equations, recast in adjoint form, and solved using direct matrix inversion techniques. This investigation is performed to demonstrate an aerodynamic shape optimization technique on a multiblock domain and its applicability to complex geometries. The objectives are accomplished by shape optimizing two aerodynamic configurations. First, the shape optimization of a transonic airfoil is performed to investigate the behavior of the method in highly nonlinear flows and the effect of different grid blocking strategies on the procedure. Secondly, shape optimization of a two-element configuration in subsonic flow is completed. Cases are presented for this configuration to demonstrate the effect of simultaneously reshaping interfering elements. The aerodynamic shape optimization is shown to produce supercritical type airfoils in the transonic flow from an initially symmetric airfoil. Multiblocking effects the path of optimization while providing similar results at the conclusion. Simultaneous reshaping of elements is shown to be more effective than individual element reshaping due to the inclusion of mutual interference effects.
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)
Barrios, S.; Merinero, R.; Lozano, R.; Orea, I.
2015-12-01
With present techniques it is difficult to determine whether the gold particles present at fluvial placers have come from one or multiple sources. Knowledge of this would be useful in prospecting for larger gold deposits. The aim of the present work was to test the potential of a technique based on modern visual and classic statistical methods to determine the single or multisource origin of gold particles at different sites in the Tormes Basin (Central Iberian Zone of the Iberian Massif, Iberian Peninsula). This basin contains numerous lode and placer gold deposits that have been exploited since ancient times. Today, gold nuggets (usually associated with quartz, 0.2-6 g in weight, 0.53-3.74 cm long and mostly discoidal in shape and of intermediate roundness) can be recovered from the sediments of the upper reaches of the River Tormes. These nuggets, as well as small gold particles collected at three gravel pits from across the basin (all of which showed abrasion marks) were examined by optical and/or environmental scanning electron microscopy, and the differences in their dimensions and morphological features noted. Simple correspondence analysis of the sphericity and roundness of the nuggets and particles was used to morphologically classify the gold samples collected at each location. The gold nuggets were best classified as elongated rods of intermediate roundness. Surprisingly, the gold particles from the most upstream and downstream gravel pits were best described as discs/sub-discs of rounded appearance, while those from the intermediate gravel pit were discs of intermediate roundness. Analysis of the variance followed by the Tukey honest significant differences test revealed the particles from the most upstream gravel pit to be significantly more flattened and smaller. These were therefore transported further from their source than the particles collected at the other two pits. These results suggest that multiple sources of sedimentary gold exist in the
Facies analysis of strawn submarine fan complex, Fort Worth basin, central Texas
Pranter, M.J. )
1990-02-01
The Fort Worth basin is a Paleozoic foreland basin located in central Texas. The basin developed in direct response to the tectonic evolution of the Ouachita thrust belt. Fan delta, submarine fan, and related slope depositional systems comprising the lower Strawn Group were deposited within the Fort Worth foreland basin and platform and shelf-edge carbonates developed on the adjacent Concho platform. The Ouachita thrust belt and related structural highlands served as the principal source areas for the thick accumulation of lower Strawn submarine fan sequences. The nature and distribution of depositional environments were controlled by active subsidence within the Fort Worth basin. Both sediment loading and tectonic loading following thrust-sheet propagation were major contributors to basin subsidence. The most rapid subsidence within the Fort Worth basin occurred during the early and late Atokan and continued into the early Desmoinesian. Decreasing subsidence and sedimentation rates during the late Desmoinesian and early Missourian established a setting for the development of upper Strawn fluvial and deltaic systems, which eventually prograded across the Fort Worth basin. Several cycles of fan progradation and abandonment are represented within the lower Strawn. The lower Strawn delta-fed submarine fan turbidites were deposited at the base of the slope forming an aggrading ramplike depositional feature. Individual facies recognized in outcrop and within the subsurface include fan delta, prodelta slope, proximal ramp, and distal ramp facies. Sandstone geometries and sediment distribution patterns reflect this ramplike feature.
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.
Characterisation of the Bahía Blanca estuary by data analysis and numerical modelling
NASA Astrophysics Data System (ADS)
Campuzano, Francisco Javier; Pierini, Jorge O.; Leitão, Paulo C.; Gómez, Eduardo A.; Neves, Ramiro J.
2014-01-01
The Bahía Blanca estuary is a complex system of channels and tidal flats where the most important deep water harbour system of Argentina is located. The main goal of the present work was to obtain a hydrodynamic conceptual model for the Bahía Blanca coastal area. For this reason, a combined analysis of observed data and numerical modelling has been performed for the whole area. The gained knowledge on the system hydrodynamics could aid in the decision support for navigation security, waste water discharges management, sediment dredging and rejection operations among other applications. Due to the Bahía Blanca coastal vast area, hydrodynamic observations are scarce and located near the populated areas. In order to describe the hydrodynamics of such a complex and large system, the analysed tidal and current data from different periods have been completed through numerical modelling. Data analysis served to determine the main processes governing the Bahía Blanca hydrodynamics, to characterise the area using general descriptors, to provide inputs for the numerical model and to aid in evaluating its performance. In addition, a 2-dimensional application was set up using the MOHID water modelling system for the Bahía Blanca estuary. This application aimed to gain a better understanding of the system dynamics, to explain and test the consistency of the observed data and to reproduce the processes taking place. Model results were in good agreement with the analysed data and served to confirm an inconsistency found on the sea level observations. The combination of both methodologies served to further describe the hydrodynamic processes governing this coastal area and also to obtain a conceptual model for the water and property circulation in the Bahía Blanca estuary.
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.