Science.gov

Sample records for physics model investigation

  1. Investigating Student Understanding of Quantum Physics: Spontaneous Models of Conductivity.

    ERIC Educational Resources Information Center

    Wittmann, Michael C.; Steinberg, Richard N.; Redish, Edward F.

    2002-01-01

    Investigates student reasoning about models of conduction. Reports that students often are unable to account for the existence of free electrons in a conductor and create models that lead to incorrect predictions and responses contradictory to expert descriptions of the physics involved. (Contains 36 references.) (Author/YDS)

  2. Preliminary Investigation of Microdosimetric Track Structure Physics Models in Geant4-DNA and RITRACKS

    PubMed Central

    Bezak, Eva

    2015-01-01

    The major differences between the physics models in Geant4-DNA and RITRACKS Monte Carlo packages are investigated. Proton and electron ionisation interactions and electron excitation interactions in water are investigated in the current work. While these packages use similar semiempirical physics models for inelastic cross-sections, the implementation of these models is demonstrated to be significantly different. This is demonstrated in a simple Monte Carlo simulation designed to identify differences in interaction cross-sections. PMID:26124856

  3. NEESROCK: A Physical and Numerical Modeling Investigation of Seismically Induced Rock-Slope Failure

    NASA Astrophysics Data System (ADS)

    Applegate, K. N.; Wartman, J.; Keefer, D. K.; Maclaughlin, M.; Adams, S.; Arnold, L.; Gibson, M.; Smith, S.

    2013-12-01

    Worldwide, seismically induced rock-slope failures have been responsible for approximately 30% of the most significant landslide catastrophes of the past century. They are among the most common, dangerous, and still today, least understood of all seismic hazards. Seismically Induced Rock-Slope Failure: Mechanisms and Prediction (NEESROCK) is a major research initiative that fully integrates physical modeling (geotechnical centrifuge) and advanced numerical simulations (discrete element modeling) to investigate the fundamental mechanisms governing the stability of rock slopes during earthquakes. The research is part of the National Science Foundation-supported Network for Earthquake Engineering Simulation Research (NEES) program. With its focus on fractures and rock materials, the project represents a significant departure from the traditional use of the geotechnical centrifuge for studying soil, and pushes the boundaries of physical modeling in new directions. In addition to advancing the fundamental understanding of the rock-slope failure process under seismic conditions, the project is developing improved rock-slope failure assessment guidelines, analysis procedures, and predictive tools. Here, we provide an overview of the project, present experimental and numerical modeling results, discuss special considerations for the use of synthetic rock materials in physical modeling, and address the suitability of discrete element modeling for simulating the dynamic rock-slope failure process.

  4. Investigation of Pupils' Levels of MVPA and VPA during Physical Education Units Focused on Direct Instruction and Tactical Games Models

    ERIC Educational Resources Information Center

    Harvey, Stephen; Smith, Lindsey; Fairclough, Stuart; Savory, Louise; Kerr, Catherine

    2015-01-01

    We investigated the moderate to vigorous physical activity (MVPA) and vigorous physical activity (VPA) levels of pupils during coeducational physical education units focused on direct instruction and tactical games models (TGM). Thirty-two children (11-12 years, 17 girls) were randomly assigned to either a direct instruction (control) or TGM…

  5. Development of a General Modeling Framework for Investigating Complex Interactions among Biological and Physical Ecosystem Dynamics

    NASA Astrophysics Data System (ADS)

    Bennett, C.; Poole, G. C.; Kimball, J. S.; Stanford, J. A.; O'Daniel, S. J.; Mertes, L. A.

    2005-05-01

    Historically, physical scientists have developed models with highly accurate governing equations, while biologists have excelled at abstraction (the strategic simplification of system complexity). These different modeling paradigms yield biological (e.g. food web) and physical (e.g. hydrologic) models that can be difficult to integrate. Complex biological dynamics may be impossible to represent with governing equations. Conversely, physical processes may be oversimplified in biological models. Using agent-based modeling, a technique applied widely in social sciences and economics, we are developing a general modeling system to integrate accurate representations of physical dynamics such as water and heat flux with abstracted biological processes such as nutrient transformations. The modeling system represents an ecosystem as a complex integrated network of intelligent physical and biological "agents" that store, transform, and trade ecosystem resources (e.g., water, heat, nutrients, carbon) using equations that describe either abstracted concepts and/or physical laws. The modular design of the system allows resource submodels to be developed independently and installed into the simulation architecture. The modeling system provides a useful heuristic tool to support integrated physical and biological research topics, such as the influence of hydrologic dynamics and spatio-temporal physical heterogeneity on trophic (food web) dynamics and/or nutrient cycling.

  6. Investigating the relationship between hydrologic model parameters and physical catchment metrics for improved modeling in data-sparse regions

    NASA Astrophysics Data System (ADS)

    Marshall, L. A.; Weber, K.; Greenwood, M. C.; Smith, T. J.; Sharma, A.

    2013-12-01

    In regions with sparse data, hydrologic modelers often endeavor to transfer information from longer-term gauged catchments to those with limited data. In this approach, it is assumed that these gauged ';surrogates' can provide useful information for those ungauged catchments that are hydrologically similar. One recent method aims to pool catchments with similar hydrologic behavior so that models may be more convincingly applied to catchments without detailed observations. An ongoing concern, however, is how to identify catchments that behave similarly in terms of hydrologic processes and thus classify catchments in terms of their modeled behavior. In this study, we investigate the complex relationship between physical catchment characteristics, hydrologic signatures, and optimized hydrologic models for regions with sparse data. We make use of a data set of over 150 catchments located in southeast Australia with basic climatic and hydrologic time series and limited information on physical catchment characteristics. A conceptual rainfall-runoff model is calibrated for each of the catchments and hierarchical clustering is performed to link catchments based on their calibrated model parameters. We then aim to isolate the physical and spatial metrics that are common to each member of a given cluster with the ultimate goal of providing insight to the selection of gauged surrogates for ungauged watersheds. A Permutational Multivariate Analysis of Variance (perMANOVA) is performed to determine if significant differences exist between clusters according to certain physical and climatic catchment descriptors. We further analyze the data using a classification tree to determine the extent to which cluster membership can be predicted by basic catchment descriptors. Our results show support for the 'surrogate' technique for hydrologic regionalization by demonstrating that the clusters, though built using calibrated model parameters, are related to clear differences in the

  7. Physically based hydrologic modeling: 1. A terrain-based model for investigative purposes

    NASA Astrophysics Data System (ADS)

    Grayson, Rodger B.; Moore, Ian D.; McMahon, Thomas A.

    1992-10-01

    THALES, a simple distributed parameter hydrologic model is presented and applied to two catchments in Australia and the United States, each with different dominant hydrologic responses. The model simulates Hortonian overland flow and runoff from saturated source areas and is used to identify some of the barriers to modeling the hydrology of small catchments. At Wagga Wagga in New South Wales, Australia, runoff is produced from saturated source areas, whereas on the Lucky Hills catchments at Walnut Gulch in Arizona, Hortonian overland flow processes dominate. Simulations at Wagga Wagga are based on published parameters and field data measured as part of an intensive field program and result in a relatively poor fit of the outflow hydrographs for a series of storms. The simulated position and growth of saturated areas coincides with the limited available information, indicating that at least the gross effects of subsurface water movement are being represented. For the Lucky Hills catchments, the hydrographs at the catchment outlet and points within the catchment are simulated for a storm series. The results are highly dependent on the parameter values, which are poorly defined, highlighting the lack of measured field data and lack of methodology for the collection of data at a scale appropriate for such models. The model structure is also shown to have a major influence on the output. The influence of simulating surface flow as sheet flow or rill flow or through a series of ephemeral gullies, as well as the choice of the surface roughness parameter and antecedent soil water conditions, is shown to have a profound effect on the distributed flow depth and velocity predictions. By fitting model parameters, a simulation assuming Hortonian overland flow produced similar results at the catchment outlet to those based on partial area runoff. These results are of concern since it is common to calibrate and verify hydrologic models based on the accuracy with which the

  8. Physical modelling in biomechanics.

    PubMed Central

    Koehl, M A R

    2003-01-01

    Physical models, like mathematical models, are useful tools in biomechanical research. Physical models enable investigators to explore parameter space in a way that is not possible using a comparative approach with living organisms: parameters can be varied one at a time to measure the performance consequences of each, while values and combinations not found in nature can be tested. Experiments using physical models in the laboratory or field can circumvent problems posed by uncooperative or endangered organisms. Physical models also permit some aspects of the biomechanical performance of extinct organisms to be measured. Use of properly scaled physical models allows detailed physical measurements to be made for organisms that are too small or fast to be easily studied directly. The process of physical modelling and the advantages and limitations of this approach are illustrated using examples from our research on hydrodynamic forces on sessile organisms, mechanics of hydraulic skeletons, food capture by zooplankton and odour interception by olfactory antennules. PMID:14561350

  9. Physics in Police Investigations.

    ERIC Educational Resources Information Center

    Young, Peter

    1980-01-01

    Described are several techniques and pieces of equipment developed by the Police Scientific Department Branch in its application of physics to police problems. Topics discussed include fingerprints, documents, and photographs. (Author/DS)

  10. Computational investigations on polymerase actions in gene transcription and replication: Combining physical modeling and atomistic simulations

    NASA Astrophysics Data System (ADS)

    Jin, Yu

    2016-01-01

    Polymerases are protein enzymes that move along nucleic acid chains and catalyze template-based polymerization reactions during gene transcription and replication. The polymerases also substantially improve transcription or replication fidelity through the non-equilibrium enzymatic cycles. We briefly review computational efforts that have been made toward understanding mechano-chemical coupling and fidelity control mechanisms of the polymerase elongation. The polymerases are regarded as molecular information motors during the elongation process. It requires a full spectrum of computational approaches from multiple time and length scales to understand the full polymerase functional cycle. We stay away from quantum mechanics based approaches to the polymerase catalysis due to abundant former surveys, while addressing statistical physics modeling approaches along with all-atom molecular dynamics simulation studies. We organize this review around our own modeling and simulation practices on a single subunit T7 RNA polymerase, and summarize commensurate studies on structurally similar DNA polymerases as well. For multi-subunit RNA polymerases that have been actively studied in recent years, we leave systematical reviews of the simulation achievements to latest computational chemistry surveys, while covering only representative studies published very recently, including our own work modeling structure-based elongation kinetic of yeast RNA polymerase II. In the end, we briefly go through physical modeling on elongation pauses and backtracking activities of the multi-subunit RNAPs. We emphasize on the fluctuation and control mechanisms of the polymerase actions, highlight the non-equilibrium nature of the operation system, and try to build some perspectives toward understanding the polymerase impacts from the single molecule level to a genome-wide scale. Project supported by the National Natural Science Foundation (Grant No. 11275022).

  11. Investigation of the Sound Pressure Level (SPL) of earphones during music listening with the use of physical ear canal models

    NASA Astrophysics Data System (ADS)

    Aying, K. P.; Otadoy, R. E.; Violanda, R.

    2015-06-01

    This study investigates on the sound pressure level (SPL) of insert-type earphones that are commonly used for music listening of the general populace. Measurements of SPL from earphones of different respondents were measured by plugging the earphone to a physical ear canal model. Durations of the earphone used for music listening were also gathered through short interviews. Results show that 21% of the respondents exceed the standard loudness/duration relation recommended by the World Health Organization (WHO).

  12. Investigating the Effect of Hydraulic Data and Heterogeneity on Stochastic Inversion of a Physically Based Groundwater Model

    NASA Astrophysics Data System (ADS)

    Wang, D.; Zhang, Y.

    2014-12-01

    This research explores the interactions between data quantity, data quality and heterogeneity resolution on stochastic inversion of a physically based model. To further investigate aquifer heterogeneity, simulations are used to examine the impact of geostatistical models on inversion quality, as well as the spatial sensitivity to heterogeneity using local and global methods. The model domain is a two-dimensional steady-state confined aquifer with lateral flows through two hydrofacies with alternating patterns.To examine general effects, the control variable method was adopted to reveal the impact of three factors on estimated hydraulic conductivity (K) and hydraulic head boundary conditions (BCs): (1) data availability, (2) data error, and (3) characterization of heterogeneity. Results show that fewer data increase model sensitivity to measurement error and heterogeneity. Extremely large data errors can cause severe model deterioration, regardless of sufficient data availability or high resolution representation of heterogeneity. Smaller data errors can alleviate the bias caused by the limited observations. For heterogeneity resolution, once general patterns of geological structures are captured, its influence is minimal compared to the other factors.Next, two geostatistical models (spherical and exponential variograms), were used to explore the representation of heterogeneity under the same nugget effects. The results show that stochastic inversion based on the exponential variogram improves both the precision and accuracy of the inverse model, as compared to the spherical variogram. This difference is particularly important for determining accurate BCs through stochastic inversion.Last, sensitivity analysis was conducted to further investigate the effect of varying the K of each hydrofacies on model inversion. Results from the partial local method show that the inversion is more sensitive to perturbations of K in regions with high heterogeneity. Using the

  13. Advanced Propulsion Physics Lab: Eagleworks Investigations

    NASA Technical Reports Server (NTRS)

    Scogin, Tyler

    2014-01-01

    Eagleworks Laboratory is an advanced propulsions physics laboratory with two primary investigations currently underway. The first is a Quantum Vacuum Plasma Thruster (QVPT or Q-thrusters), an advanced electric propulsion technology in the development and demonstration phase. The second investigation is in Warp Field Interferometry (WFI). This is an investigation of Dr. Harold "Sonny" White's theoretical physics models for warp field equations using optical experiments in the Electro Optical laboratory (EOL) at Johnson Space Center. These investigations are pursuing technology necessary to enable human exploration of the solar system and beyond.

  14. Physical analog (centrifuge) model investigation of contrasting structural styles in the Salt Range and Potwar Plateau, northern Pakistan

    NASA Astrophysics Data System (ADS)

    Faisal, Shah; Dixon, John M.

    2015-08-01

    We use scaled physical analog (centrifuge) modeling to investigate along- and across-strike structural variations in the Salt Range and Potwar Plateau of the Himalayan foreland fold-thrust belt of Pakistan. The models, composed of interlayered plasticine and silicone putty laminae, comprise four mechanical units representing the Neoproterozoic Salt Range Formation (basal detachment), Cambrian-Eocene carapace sequence, and Rawalpindi and Siwalik Groups (Neogene molasse), on a rigid base representing the Indian craton. Pre-cut ramps simulate basement faults with various structural geometries. A pre-existing north-dipping basement normal fault under the model foreland induces a frontal ramp and a prominent fault-bend-fold culmination, simulating the Salt Range. The ramp localizes displacement on a frontal thrust that occurs out-of-sequence with respect to other foreland folds and thrusts. With a frontal basement fault terminating to the east against a right-stepping, east-dipping lateral ramp, deformation propagates further south in the east; strata to the east of the lateral ramp are telescoped in ENE-trending detachment folds, fault-propagation folds and pop-up structures above a thick basal detachment (Salt Range Formation), in contrast to translated but less-deformed strata with E-W-trending Salt-Range structures to the west. The models are consistent with Salt Range-Potwar Plateau structural style contrasts being due to basement fault geometry and variation in detachment thickness.

  15. Numerical investigation of the physical model of a high-power electromagnetic wave in a magnetically insulated transmission line

    SciTech Connect

    Samokhin, A. A.

    2010-02-15

    An efficient numerical code for simulating the propagation of a high-power electromagnetic pulse in a vacuum transmission line is required to study the physical phenomena occurring in such a line, to analyze the operation of present-day megavolt generators at an {approx}10-TW power level, and to design such new devices. The main physical theoretical principles are presented, and the stability of flows in the near-threshold region at the boundary of the regime of magnetic self-insulation is investigated based on one-dimensional telegraph equations with electron losses. Numerical (difference) methods-specifically, a method of characteristics and a finite-difference scheme-are described and their properties and effectiveness are compared by analyzing the high-frequency modes.

  16. Investigation for improving Global Positioning System (GPS) orbits using a discrete sequential estimator and stochastic models of selected physical processes

    NASA Technical Reports Server (NTRS)

    Goad, Clyde C.; Chadwell, C. David

    1993-01-01

    GEODYNII is a conventional batch least-squares differential corrector computer program with deterministic models of the physical environment. Conventional algorithms were used to process differenced phase and pseudorange data to determine eight-day Global Positioning system (GPS) orbits with several meter accuracy. However, random physical processes drive the errors whose magnitudes prevent improving the GPS orbit accuracy. To improve the orbit accuracy, these random processes should be modeled stochastically. The conventional batch least-squares algorithm cannot accommodate stochastic models, only a stochastic estimation algorithm is suitable, such as a sequential filter/smoother. Also, GEODYNII cannot currently model the correlation among data values. Differenced pseudorange, and especially differenced phase, are precise data types that can be used to improve the GPS orbit precision. To overcome these limitations and improve the accuracy of GPS orbits computed using GEODYNII, we proposed to develop a sequential stochastic filter/smoother processor by using GEODYNII as a type of trajectory preprocessor. Our proposed processor is now completed. It contains a correlated double difference range processing capability, first order Gauss Markov models for the solar radiation pressure scale coefficient and y-bias acceleration, and a random walk model for the tropospheric refraction correction. The development approach was to interface the standard GEODYNII output files (measurement partials and variationals) with software modules containing the stochastic estimator, the stochastic models, and a double differenced phase range processing routine. Thus, no modifications to the original GEODYNII software were required. A schematic of the development is shown. The observational data are edited in the preprocessor and the data are passed to GEODYNII as one of its standard data types. A reference orbit is determined using GEODYNII as a batch least-squares processor and the

  17. Investigating ice cliff evolution and contribution to glacier mass-balance using a physically-based dynamic model

    NASA Astrophysics Data System (ADS)

    Buri, Pascal; Miles, Evan; Ragettli, Silvan; Brun, Fanny; Steiner, Jakob; Pellicciotti, Francesca

    2016-04-01

    Supraglacial cliffs are a surface feature typical of debris-covered glaciers, affecting surface evolution, glacier downwasting and mass balance by providing a direct ice-atmosphere interface. As a result, melt rates can be very high and ice cliffs may account for a significant portion of the total glacier mass loss. However, their contribution to glacier mass balance has rarely been quantified through physically-based models. Most cliff energy balance models are point scale models which calculate energy fluxes at individual cliff locations. Results from the only grid based model to date accurately reflect energy fluxes and cliff melt, but modelled backwasting patterns are in some cases unrealistic, as the distribution of melt rates would lead to progressive shallowing and disappearance of cliffs. Based on a unique multitemporal dataset of cliff topography and backwasting obtained from high-resolution terrestrial and aerial Structure-from-Motion analysis on Lirung Glacier in Nepal, it is apparent that cliffs exhibit a range of behaviours but most do not rapidly disappear. The patterns of evolution cannot be explained satisfactorily by atmospheric melt alone, and are moderated by the presence of supraglacial ponds at the base of cliffs and by cliff reburial with debris. Here, we document the distinct patterns of evolution including disappearance, growth and stability. We then use these observations to improve the grid-based energy balance model, implementing periodic updates of the cliff geometry resulting from modelled melt perpendicular to the ice surface. Based on a slope threshold, pixels can be reburied by debris or become debris-free. The effect of ponds are taken into account through enhanced melt rates in horizontal direction on pixels selected based on an algorithm considering distance to the water surface, slope and lake level. We use the dynamic model to first study the evolution of selected cliffs for which accurate, high resolution DEMs are available

  18. Kinesthetic Investigations in the Physics Classroom

    ERIC Educational Resources Information Center

    Whitworth, Brooke A.; Chiu, Jennifer L.; Bell, Randy L.

    2014-01-01

    Creating investigations that allow students to see physics in their everyday world and to be kinesthetically active outside of the traditional physics classroom can be incredibly engaging and effective. The investigations we developed were inquiry investigations in which students engaged in concrete experiences before we discussed the abstract…

  19. Physics. Teacher's Guide. Investigations in Natural Science.

    ERIC Educational Resources Information Center

    Renner, John W.; And Others

    Investigations in Natural Science is a program in secondary school biology, chemistry, and physics based upon the description of science as a quest for knowledge, not the knowledge itself. This teaching guide is designed for use with the 36 physics investigations found in the student manual. These investigations focus on concepts related to:…

  20. Investigation of Higher Brain Functions in Music Composition Using Models of the Cortex Based on Physical System Analogies.

    NASA Astrophysics Data System (ADS)

    Leng, Xiaodan

    The trion model was developed using the Mountcastle organizational principle for the column as the basic neuronal network in the cortex and the physical system analogy of Fisher's ANNNI spin model. An essential feature is that it is highly structured in time and in spatial connections. Simulations of a network of trions have shown that large numbers of quasi-stable, periodic spatial-temporal firing patterns can be excited. Characteristics of these patterns include the quality of being readily enhanced by only a small change in connection strengths, and that the patterns evolve in certain natural sequences from one to another. With only somewhat different parameters than used for studying memory and pattern recognition, much more flowing and intriguing patterns emerged from the simulations. The results were striking when these probabilistic evolutions were mapped onto pitches and instruments to produce music: For example different simple mappings of the same evolution give music having the "flavor" of a minuet, a waltz, folk music, or styles of specific periods. A theme can be learned so that evolutions have this theme and its variations reoccurring more often. That the trion model is a viable model for the coding of musical structure in human composition and perception is suggested. It is further proposed that model is relevant for examining creativity in the higher cognitive functions of mathematics and chess, which are similar to music. An even higher level of cortical organization was modeled by coupling together several trion networks. Further, one of the crucial features of higher brain function, especially in music composition or appreciation, is the role of emotion and mood as controlled by the many neuromodulators or neuropeptides. The MILA model whose underlying basis is zero-level representation of Kac-Moody algebra is used to modulate periodically the firing threshold of each network. Our preliminary results show that the introduction of "neuromodulation

  1. Physics. Student Investigations and Readings. Investigations in Natural Science.

    ERIC Educational Resources Information Center

    Renner, John W.; And Others

    Investigations in Natural Science is a program in secondary school biology, chemistry, and physics based upon the description of science as a quest for knowledge, not the knowledge itself. This student manual contains the 36 physics investigations which focus on concepts related to: movement; vectors; falling objects; force and acceleration; a…

  2. Numerical investigation of the Taylor-Couette and Batchelor flows with heat transfer: physics and numerical modelling

    NASA Astrophysics Data System (ADS)

    Kiełczewski, K.; Tuliszka-Sznitko, E.; Bontoux, P.

    2014-08-01

    In the paper the authors present the results obtained during a numerical investigation (Direct Numerical Simulation/Spectral Vanishing Viscosity method - DNS/SVV) of a flow with heat transfer in rotating cavities (i.e. the flow between two concentric disks and two concentric cylinders). These model flows are useful from numerical and experimental point of view among others because of the simplicity of their geometry. Simultaneously, the flows in rotating cavities appear in numerous industrial installations and machines in the field of mechanics and chemistry, e.g., in ventilation installations, desalination tanks and waste water tanks, in cooling system, in gas turbines and axial compressors. In the paper attention is focused on the laminar-turbulent region in the configuration of the large aspect ratio i.e. Taylor-Couette flow (a Batchelor flow case of small aspect ratio Γ = 0.04 is also presented for comparison). The main purpose of computations is to investigate the influence of different parameters (the aspect ratio, the end-wall boundary conditions and temperature gradient) on the flow structure and flow characteristics. For the non-isothermal flow cases the Nusselt number distributions along cylinders are presented and are correlated with the flow structures. The λ2 method has been used for visualization.

  3. Beyond Standard Model Physics

    SciTech Connect

    Bellantoni, L.

    2009-11-01

    There are many recent results from searches for fundamental new physics using the TeVatron, the SLAC b-factory and HERA. This talk quickly reviewed searches for pair-produced stop, for gauge-mediated SUSY breaking, for Higgs bosons in the MSSM and NMSSM models, for leptoquarks, and v-hadrons. There is a SUSY model which accommodates the recent astrophysical experimental results that suggest that dark matter annihilation is occurring in the center of our galaxy, and a relevant experimental result. Finally, model-independent searches at D0, CDF, and H1 are discussed.

  4. Physical, Chemical, and Immunohistochemical Investigation of the Damage to Salivary Glands in a Model of Intoxication with Aluminium Citrate

    PubMed Central

    da Costa, Natacha M. M.; Correa, Russell S.; Júnior, Ismael S. M.; Figueiredo, Adilson J. R.; Vilhena, Kelly F. B.; Farias-Junior, Paulo M. A.; Teixeira, Francisco B.; Ferreira, Nayana M. M.; Pereira-Júnior, João B.; Dantas, Kelly das Graças F.; da Silva, Marcia C. F.; Silva-Junior, Ademir F.; Alves-Junior, Sergio de M.; Pinheiro, João de Jesus V.; Lima, Rafael Rodrigues

    2014-01-01

    Aluminum absorption leads to deposits in several tissues. In this study, we have investigated, to our knowledge for the first time, aluminum deposition in the salivary glands in addition to the resultant cellular changes in the parotid and submandibular salivary glands in a model of chronic intoxication with aluminum citrate in rats. Aluminum deposits were observed in the parotid and submandibular glands. Immunohistochemical evaluation of cytokeratin-18 revealed a decreased expression in the parotid gland with no changes in the submandibular gland. A decreased expression of α-smooth muscle actin was observed in the myoepithelial cells of both glands. The expression of metallothionein I and II (MT-I/II), a group of metal-binding proteins, which are useful indicators for detecting physiological responses to metal exposure, was higher in both glands. In conclusion, we have shown that at a certain time and quantity of dosage, aluminum citrate promotes aluminum deposition in the parotid and submandibular glands, leads to an increased expression of MT-I/II in both the glands, damages the cytoskeleton of the myoepithelial cells in both glands, and damages the cytoskeleton of the acinar/ductal cells of the parotid glands, with the submandibular glands showing resistance to the toxicity of the latter. PMID:25464135

  5. Physical, chemical, and immunohistochemical investigation of the damage to salivary glands in a model of intoxication with aluminium citrate.

    PubMed

    da Costa, Natacha M M; Correa, Russell S; Júnior, Ismael S M; Figueiredo, Adilson J R; Vilhena, Kelly F B; Farias-Junior, Paulo M A; Teixeira, Francisco B; Ferreira, Nayana M M; Pereira-Júnior, João B; Dantas, Kelly das Graças F; da Silva, Marcia C F; Silva-Junior, Ademir F; Alves-Junior, Sergio de M; Pinheiro, João de Jesus V; Lima, Rafael Rodrigues

    2014-12-01

    Aluminum absorption leads to deposits in several tissues. In this study, we have investigated, to our knowledge for the first time, aluminum deposition in the salivary glands in addition to the resultant cellular changes in the parotid and submandibular salivary glands in a model of chronic intoxication with aluminum citrate in rats. Aluminum deposits were observed in the parotid and submandibular glands. Immunohistochemical evaluation of cytokeratin-18 revealed a decreased expression in the parotid gland with no changes in the submandibular gland. A decreased expression of α-smooth muscle actin was observed in the myoepithelial cells of both glands. The expression of metallothionein I and II (MT-I/II), a group of metal-binding proteins, which are useful indicators for detecting physiological responses to metal exposure, was higher in both glands. In conclusion, we have shown that at a certain time and quantity of dosage, aluminum citrate promotes aluminum deposition in the parotid and submandibular glands, leads to an increased expression of MT-I/II in both the glands, damages the cytoskeleton of the myoepithelial cells in both glands, and damages the cytoskeleton of the acinar/ductal cells of the parotid glands, with the submandibular glands showing resistance to the toxicity of the latter.

  6. Physical and chemical investigations on natural dyes

    NASA Astrophysics Data System (ADS)

    Acquaviva, S.; D'Anna, E.; de Giorgi, M. L.; Della Patria, A.; Baraldi, P.

    2010-09-01

    Natural dyes have been used extensively in the past for many purposes, such us to colour fibers and to produce inks, watercolours and paints, but their use declined rapidly after the discovery of synthetic colours. Nowadays we witness a renewed interest, as natural dyes are neither toxic nor polluting. In this work, physical and chemical properties of four selected dyes, namely red (Madder), yellow (Weld and Turmeric) and blue (Woad) colours, produced by means of traditional techniques at the Museo dei Colori Naturali (Lamoli, Italy), have been investigated. The chromatic properties have been studied through the reflectance spectroscopy, a non-invasive technique for the characterisation of chromaticity. Reflection spectra both from powders and egg-yolk tempera models have been acquired to provide the typical features of the dyes in the UV-vis spectral range. Moreover, to assess the feasibility of laser cleaning procedures, tempera layers were investigated after irradiation with an excimer laser. Micro Raman spectroscopy, Scanning Electron Microscopy and Energy Dispersive X-Ray analyses have complemented the survey, returning compositional and morphological information as well. Efforts have been made to give scientific feedback to the production processes and to support the research activity in the restoration of the artworks where these dyes were employed.

  7. Ionospheric irregularity physics modelling

    SciTech Connect

    Ossakow, S.L.; Keskinen, M.J.; Zalesak, S.T.

    1982-01-01

    Theoretical and numerical simulation techniques have been employed to study ionospheric F region plasma cloud striation phenomena, equatorial spread F phenomena, and high latitude diffuse auroral F region irregularity phenomena. Each of these phenomena can cause scintillation effects. The results and ideas from these studies are state-of-the-art, agree well with experimental observations, and have induced experimentalists to look for theoretically predicted results. One conclusion that can be drawn from these studies is that ionospheric irregularity phenomena can be modelled from a first principles physics point of view. Theoretical and numerical simulation results from the aforementioned ionospheric irregularity areas will be presented.

  8. Investigating the effect of an education plan based on the health belief model on the physical activity of women who are at risk for hypertension

    PubMed Central

    Hoseini, Habibollah; Maleki, Fatemeh; Moeini, Mahin; Sharifirad, Gholam Reza

    2014-01-01

    Background: Hypertension is the main risk factor of many diseases and the main reason of death all over the world. Because the signs of hypertension are not clear, people do not feel its dangers and do not believe they are at risk. This problem makes preventing hypertension a great challenge for the health system. One factor that is related to lifestyle and is effective in preventing hypertension is increasing exercise. The aim of this study is investigate the effect of an education plan based on the health belief model on the physical activity of women who are at risk for hypertension. Materials and Methods: This is a field experimental study. Field of study was two health care centers in Isfahan, which were selected through simple random sampling. Ninety-two females who were at risk for hypertension were the subjects of study. Subjects were selected through systematic sampling. Beck questionnaire was used to evaluate the physical activity of both experimental and control group subjects before and 2 months after the intervention. The intervention plan was three education sections that were conducted in 4 weeks. The data were analyzed by descriptive statistical tests and inferential tests of repetitive variance analysis and t-test through SPSS. Results: The results showed that the average of physical activity increased significantly in the intervention group 2 months after education (P = 0.03). Conclusions: The findings of the study confirm the efficiency of education plan based on the health belief model on the physical activity of women who are at risk for hypertension. PMID:25558264

  9. Physical Models of Cognition

    NASA Technical Reports Server (NTRS)

    Zak, Michail

    1994-01-01

    This paper presents and discusses physical models for simulating some aspects of neural intelligence, and, in particular, the process of cognition. The main departure from the classical approach here is in utilization of a terminal version of classical dynamics introduced by the author earlier. Based upon violations of the Lipschitz condition at equilibrium points, terminal dynamics attains two new fundamental properties: it is spontaneous and nondeterministic. Special attention is focused on terminal neurodynamics as a particular architecture of terminal dynamics which is suitable for modeling of information flows. Terminal neurodynamics possesses a well-organized probabilistic structure which can be analytically predicted, prescribed, and controlled, and therefore which presents a powerful tool for modeling real-life uncertainties. Two basic phenomena associated with random behavior of neurodynamic solutions are exploited. The first one is a stochastic attractor ; a stable stationary stochastic process to which random solutions of a closed system converge. As a model of the cognition process, a stochastic attractor can be viewed as a universal tool for generalization and formation of classes of patterns. The concept of stochastic attractor is applied to model a collective brain paradigm explaining coordination between simple units of intelligence which perform a collective task without direct exchange of information. The second fundamental phenomenon discussed is terminal chaos which occurs in open systems. Applications of terminal chaos to information fusion as well as to explanation and modeling of coordination among neurons in biological systems are discussed. It should be emphasized that all the models of terminal neurodynamics are implementable in analog devices, which means that all the cognition processes discussed in the paper are reducible to the laws of Newtonian mechanics.

  10. MODELING PHYSICAL HABITAT PARAMETERS

    EPA Science Inventory

    Salmonid populations can be affected by alterations in stream physical habitat. Fish productivity is determined by the stream's physical habitat structure ( channel form, substrate distribution, riparian vegetation), water quality, flow regime and inputs from the watershed (sedim...

  11. Evolutionary Industrial Physical Model Generation

    NASA Astrophysics Data System (ADS)

    Carrascal, Alberto; Alberdi, Amaia

    Both complexity and lack of knowledge associated to physical processes makes physical models design an arduous task. Frequently, the only available information about the physical processes are the heuristic data obtained from experiments or at best a rough idea on what are the physical principles and laws that underlie considered physical processes. Then the problem is converted to find a mathematical expression which fits data. There exist traditional approaches to tackle the inductive model search process from data, such as regression, interpolation, finite element method, etc. Nevertheless, these methods either are only able to solve a reduced number of simple model typologies, or the given black-box solution does not contribute to clarify the analyzed physical process. In this paper a hybrid evolutionary approach to search complex physical models is proposed. Tests carried out on a real-world industrial physical process (abrasive water jet machining) demonstrate the validity of this approach.

  12. Building Mental Models by Dissecting Physical Models

    ERIC Educational Resources Information Center

    Srivastava, Anveshna

    2016-01-01

    When students build physical models from prefabricated components to learn about model systems, there is an implicit trade-off between the physical degrees of freedom in building the model and the intensity of instructor supervision needed. Models that are too flexible, permitting multiple possible constructions require greater supervision to…

  13. Practitioner review: physical investigations in mental retardation.

    PubMed

    Gillberg, C

    1997-11-01

    Mental retardation occurs in more than 1% of the child population. A cause can be found in almost 80% of individuals with severe mental retardation, but in fewer than 40% of those with mild mental retardation. A work-up is indicated in all cases of mental retardation. A medical doctor with specific training in the field is needed to make "decision-tree diagnosis" and to suggest the most appropriate physical investigations in each case. This paper provides practical guidelines for diagnosis and work-up both in severe and mild mental retardation. PMID:9413789

  14. Streamflow generation in humid West Africa: the role of Bas-fonds investigated with a physically based model of the Critical Zone

    NASA Astrophysics Data System (ADS)

    Hector, B.; Cohard, J. M.; Séguis, L.

    2015-12-01

    In West Africa, the drought initiated in the 70's-80's together with intense land-use change due to increasing food demand produced very contrasted responses on water budgets of the critical zone (CZ) depending on the lithological and pedological contexts. In Sahel, streamflow increased, mostly due to increasing hortonian runoff from soil crusting, and so did groundwater storage. On the contrary, in the more humid southern Sudanian area, streamflow decreased and no clear signal has been observed concerning water storage in this hard-rock basement area. There, Bas-fonds are fundamental landscape features. They are seasonally water-logged valley bottoms from which first order streams originate, mostly composed of baseflow. They are a key feature for understanding streamflow generation processes. They also carry an important agronomic potential due to their moisture and nutrient availability. The role of Bas-fond in streamflow generation processes is investigated using a physically-based coupled model of the CZ, ParFlow-CLM at catchment scale (10km²). The model is evaluated against classical hydrological measurements (water table, soil moisture, streamflow, fluxes), acquired in the AMMA-CATCH observing system for the West African monsoon, but also hybrid gravity data which measure integrated water storage changes. The bas-fond system is shown to be composed of two components with different time scales. The slow component is characterized by the seasonal and interannual amplitude of the permanent water table, which is disconnected from streams, fed by direct recharge and lowered by evapotranspiration, mostly from riparian areas. The fast component is characterized by thresholds in storage and perched and permanent water tables surrounding the bas-fond during the wet season, which are linked with baseflow generation. This is a first step toward integrating these features into larger scale modeling of the critical zone for evaluating the effect of precipitation

  15. Improvement of Learning Process and Learning Outcomes in Physics Learning by Using Collaborative Learning Model of Group Investigation at High School (Grade X, SMAN 14 Jakarta)

    ERIC Educational Resources Information Center

    Astra, I. Made; Wahyuni, Citra; Nasbey, Hadi

    2015-01-01

    The aim of this research is to improve the quality of physics learning through application of collaborative learning of group investigation at grade X MIPA 2 SMAN 14 Jakarta. The method used in this research is classroom action research. This research consisted of three cycles was conducted from April to May in 2014. Each cycle consists of…

  16. An investigation of the effect of instruction in physics on the formation of mental models for problem-solving in the context of simple electric circuits

    NASA Astrophysics Data System (ADS)

    Beh, Kian Lim

    2000-10-01

    This study was designed to explore the effect of a typical traditional method of instruction in physics on the formation of useful mental models among college students for problem-solving using simple electric circuits as a context. The study was also aimed at providing a comprehensive description of the understanding regarding electric circuits among novices and experts. In order to achieve these objectives, the following two research approaches were employed: (1) A students survey to collect data from 268 physics students; and (2) An interview protocol to collect data from 23 physics students and 24 experts (including 10 electrical engineering graduates, 4 practicing electrical engineers, 2 secondary school physics teachers, 8 physics lecturers, and 4 electrical engineers). Among the major findings are: (1) Most students do not possess accurate models of simple electric circuits as presented implicitly in physics textbooks; (2) Most students display good procedural understanding for solving simple problems concerning electric circuits but have no in-depth conceptual understanding in terms of practical knowledge of current, voltage, resistance, and circuit connections; (3) Most students encounter difficulty in discerning parallel connections that are drawn in a non-conventional format; (4) After a year of college physics, students show significant improvement in areas, including practical knowledge of current and voltage, ability to compute effective resistance and capacitance, ability to identify circuit connections, and ability to solve problems; however, no significance was found in practical knowledge of resistance and ability to connect circuits; and (5) The differences and similarities between the physics students and the experts include: (a) Novices perceive parallel circuits more in terms of 'branch', 'current', and 'resistors with the same resistance' while experts perceive parallel circuits more in terms of 'node', 'voltage', and 'less resistance'; and

  17. Physical Modeling of the Piano

    NASA Astrophysics Data System (ADS)

    Giordano, N.; Jiang, M.

    2004-12-01

    A project aimed at constructing a physical model of the piano is described. Our goal is to calculate the sound produced by the instrument entirely from Newton's laws. The structure of the model is described along with experiments that augment and test the model calculations. The state of the model and what can be learned from it are discussed.

  18. Modeling QCD for Hadron Physics

    SciTech Connect

    Tandy, P. C.

    2011-10-24

    We review the approach to modeling soft hadron physics observables based on the Dyson-Schwinger equations of QCD. The focus is on light quark mesons and in particular the pseudoscalar and vector ground states, their decays and electromagnetic couplings. We detail the wide variety of observables that can be correlated by a ladder-rainbow kernel with one infrared parameter fixed to the chiral quark condensate. A recently proposed novel perspective in which the quark condensate is contained within hadrons and not the vacuum is mentioned. The valence quark parton distributions, in the pion and kaon, as measured in the Drell Yan process, are investigated with the same ladder-rainbow truncation of the Dyson-Schwinger and Bethe-Salpeter equations.

  19. Modeling QCD for Hadron Physics

    NASA Astrophysics Data System (ADS)

    Tandy, P. C.

    2011-10-01

    We review the approach to modeling soft hadron physics observables based on the Dyson-Schwinger equations of QCD. The focus is on light quark mesons and in particular the pseudoscalar and vector ground states, their decays and electromagnetic couplings. We detail the wide variety of observables that can be correlated by a ladder-rainbow kernel with one infrared parameter fixed to the chiral quark condensate. A recently proposed novel perspective in which the quark condensate is contained within hadrons and not the vacuum is mentioned. The valence quark parton distributions, in the pion and kaon, as measured in the Drell Yan process, are investigated with the same ladder-rainbow truncation of the Dyson-Schwinger and Bethe-Salpeter equations.

  20. Physical Modeling of Microtubules Network

    NASA Astrophysics Data System (ADS)

    Allain, Pierre; Kervrann, Charles

    2014-10-01

    Microtubules (MT) are highly dynamic tubulin polymers that are involved in many cellular processes such as mitosis, intracellular cell organization and vesicular transport. Nevertheless, the modeling of cytoskeleton and MT dynamics based on physical properties is difficult to achieve. Using the Euler-Bernoulli beam theory, we propose to model the rigidity of microtubules on a physical basis using forces, mass and acceleration. In addition, we link microtubules growth and shrinkage to the presence of molecules (e.g. GTP-tubulin) in the cytosol. The overall model enables linking cytosol to microtubules dynamics in a constant state space thus allowing usage of data assimilation techniques.

  1. Investigation of the behavior of VOCs in ground water across fine- and coarse-grained geological contacts using a medium-scale physical model

    SciTech Connect

    Hoffman, F.; Chiarappa, M.L.

    1998-03-01

    One of the serious impediments to the remediation of ground water contaminated with volatile organic compounds (VOCs) is that the VOCs are retarded with respect to the movement of the ground water. Although the processes that result in VOC retardation are poorly understood, we have developed a conceptual model that includes several retarding mechanisms. These include adsorption to inorganic surfaces, absorption to organic carbon, and diffusion into areas of immobile waters. This project was designed to evaluate the relative contributions of these mechanisms; by improving our understanding, we hope to inspire new remediation technologies or approaches. Our project consisted of a series of column experiments designed to measure the retardation, in different geological media, of four common ground water VOCs (chloroform, carbon tetrachloride, trichloroethylene, and tetrachloroethylene) which have differing physical and chemical characteristics. It also included a series of diffusion parameters that constrain the model, we compared the data from these experiments to the output of a computational model.

  2. A new approach of monitoring and physically-based modelling to investigate urban wash-off process on a road catchment near Paris.

    PubMed

    Hong, Yi; Bonhomme, Celine; Le, Minh-Hoang; Chebbo, Ghassan

    2016-10-01

    Nowadays, the increasing use of vehicles is causing contaminated stormwater runoff to drain from roads. The detailed understanding of urban wash-off processes is essential for addressing urban management issues. However, existing modelling approaches are rarely applied for these objectives due to the lack of realistic input data, unsuitability of physical descriptions, and inadequate documentation of model testing. In this context, we implement a method of coupling monitoring surveys with the physically-based FullSWOF (Full Shallow Water equations for Overland Flow) model (Delestre et al., 2014) and the process-based H-R (Hairsine-Rose) model (Hairsine and Rose, 1992a, 1992b) to evaluate urban wash-off process on a road catchment near Paris (Le Perreux sur Marne, Val de Marne, France, 2661 m(2)). This work is the first time that such an approach is applied for road wash-off modelling in the context of urban stormwater runoff. On-site experimental measurements have shown that only the finest particles of the road dry stocks could be transferred to the sewer inlet during rainfall events, and most Polycyclic Aromatic Hydrocarbons (PAHs) are found in the particulate phase. Simulations over different rainfall events represent promising results in reproducing the various dynamics of water flows and sediment transports at the road catchment scale. Elementary Effects method is applied for sensitivity analysis. It is confirmed that settling velocity (Vs) and initial dry stocks (S) are the most influential parameters in both overall and higher order effects. Furthermore, flow-driven detachment seems to be insignificant in our case study, while raindrop-driven detachment is shown to be the major force for detaching sediment from the studied urban surface. Finally, a multiple sediment classification regarding the Particle Size Distribution (PSD) can be suggested for improving the model performance for future studies. PMID:27328366

  3. A new approach of monitoring and physically-based modelling to investigate urban wash-off process on a road catchment near Paris.

    PubMed

    Hong, Yi; Bonhomme, Celine; Le, Minh-Hoang; Chebbo, Ghassan

    2016-10-01

    Nowadays, the increasing use of vehicles is causing contaminated stormwater runoff to drain from roads. The detailed understanding of urban wash-off processes is essential for addressing urban management issues. However, existing modelling approaches are rarely applied for these objectives due to the lack of realistic input data, unsuitability of physical descriptions, and inadequate documentation of model testing. In this context, we implement a method of coupling monitoring surveys with the physically-based FullSWOF (Full Shallow Water equations for Overland Flow) model (Delestre et al., 2014) and the process-based H-R (Hairsine-Rose) model (Hairsine and Rose, 1992a, 1992b) to evaluate urban wash-off process on a road catchment near Paris (Le Perreux sur Marne, Val de Marne, France, 2661 m(2)). This work is the first time that such an approach is applied for road wash-off modelling in the context of urban stormwater runoff. On-site experimental measurements have shown that only the finest particles of the road dry stocks could be transferred to the sewer inlet during rainfall events, and most Polycyclic Aromatic Hydrocarbons (PAHs) are found in the particulate phase. Simulations over different rainfall events represent promising results in reproducing the various dynamics of water flows and sediment transports at the road catchment scale. Elementary Effects method is applied for sensitivity analysis. It is confirmed that settling velocity (Vs) and initial dry stocks (S) are the most influential parameters in both overall and higher order effects. Furthermore, flow-driven detachment seems to be insignificant in our case study, while raindrop-driven detachment is shown to be the major force for detaching sediment from the studied urban surface. Finally, a multiple sediment classification regarding the Particle Size Distribution (PSD) can be suggested for improving the model performance for future studies.

  4. [Investigation of physical activity among adults].

    PubMed

    Meboniia, N M; Kalandadze, I L; Chachava, T D; Sadzhaia, M V

    2006-06-01

    Lack of physical activity as well as smoking, overweight, high blood cholesterol level and hypertension are independent risk factors for development of various chronic diseases. Lack of physical activity is a main cause of non-communicable diseases morbidity and mortality in about 23% of cases (WHO, 2002). Goal of the survey was the identification and characteristics of physical activity among adults. We conducted epidemiologic survey among the school-children and students in Tbilisi. Survey was carried out in 40 schools from all regions of Tbilisi and 9 state and private institutes. Schools were selected by randomized trail in each region of Tbilisi and in each school were questioned all teen-agers from 14-17 year old. For selecting group of survey was used method of "proportional probability of value". There were questioned 2 500 school children and 1000 students, 38% boys and 62% girls. The results of survey ascertained that 23,5%-39,5% of respondents are training or engaged in sport everyday, or several times per week; 17,2% - once in a month; 9,3% once in a year; or 10,5% - never. Adults are less informed about useful effect of physical activity. Respondents had different point of on the role of physical activity: some of them thought it controls weight; others - prevents development of different diseases; the rest thinks that it copes with psycho-emotional stress, and none of them precise about effectiveness of physical activity in all cases mentioned above. Propaganda of healthy life stile must be associated with the effectiveness of physical activity on health.

  5. Using a physically-based model, tRIBS-Erosion, for investigating the effects of climate change in semi-arid headwater basins.

    NASA Astrophysics Data System (ADS)

    Francipane, Antonio; Fatichi, Simone; Ivanov, Valeriy Y.; Noto, Leonardo V.

    2013-04-01

    Soil erosion due to rainfall detachment and flow entrainment of soil particles is a physical process responsible for a continuous evolution of landscapes. The rate and spatial distribution of this phenomenon depend on several factors such as climate, hydrologic regime, geomorphic characteristics, and vegetation of a basin. Many studies have demonstrated that climate-erosion linkage in particular influences basin sediment yield and landscape morphology. Although soil erosion rates are expected to change in response to climate, these changes can be highly non-linear and thus require mechanistic understanding of underlying causes. In this study, an integrated geomorphic component of the physically-based, spatially distributed hydrological model, tRIBS, the TIN-based Real-time Integrated Basin Simulator, is used to analyze the sensitivity of semi-arid headwater basins to climate change. Downscaled outputs of global circulation models are used to inform a stochastic weather generator that produces an ensemble of climate scenarios for an area in the Southwest U.S. The ensemble is used as input to the integrated model that is applied to different headwater basins of the Walnut Gulch Experimental Watershed to understand basin response to climate change in terms of runoff and sediment yield. Through a model application to multiple catchments, a scaling relationship between specific sediment yield and drainage basin area is also addressed and probabilistic inferences on future changes in catchment runoff and yield are drawn. Geomorphological differences among catchments do not influence specific changes in runoff and sediment transport that are mostly determined by precipitation changes. Despite a large uncertainty dictated by climate change projections and stochastic variability, sediment transport is predicted to decrease despite a non-negligible possibility of larger runoff rates.

  6. Physics beyond the standard model

    SciTech Connect

    Womersley, J.

    2000-01-24

    The author briefly summarizes the prospects for extending the understanding of physics beyond the standard model within the next five years. He interprets ``beyond the standard model'' to mean the physics of electroweak symmetry breaking, including the standard model Higgs boson. The nature of this TeV-scale new physics is perhaps the most crucial question facing high-energy physics, but one should recall (neutrino oscillations) that there is ample evidence for interesting physics in the flavour section too. In the next five years, before the LHC starts operations, the facilities available will be LEP2, HERA and the Fermilab Tevatron. He devotes a bit more time to the Tevatron as it is a new initiative for United Kingdom institutions. The Tevatron schedule now calls for data taking in Run II, using two upgraded detectors, to begin on March 1, 2001, with 2 fb{sup {minus}1} accumulated in the first two years. A nine-month shutdown will follow, to allow new silicon detector layers to be installed, and then running will resume with a goal of accumulating 15 fb{sup {minus}1} (or more) by 2006.

  7. Standard Model of Particle Physics--a health physics perspective.

    PubMed

    Bevelacqua, J J

    2010-11-01

    The Standard Model of Particle Physics is reviewed with an emphasis on its relationship to the physics supporting the health physics profession. Concepts important to health physics are emphasized and specific applications are presented. The capability of the Standard Model to provide health physics relevant information is illustrated with application of conservation laws to neutron and muon decay and in the calculation of the neutron mean lifetime.

  8. Building mental models by dissecting physical models.

    PubMed

    Srivastava, Anveshna

    2016-01-01

    When students build physical models from prefabricated components to learn about model systems, there is an implicit trade-off between the physical degrees of freedom in building the model and the intensity of instructor supervision needed. Models that are too flexible, permitting multiple possible constructions require greater supervision to ensure focused learning; models that are too constrained require less supervision, but can be constructed mechanically, with little to no conceptual engagement. We propose "model-dissection" as an alternative to "model-building," whereby instructors could make efficient use of supervisory resources, while simultaneously promoting focused learning. We report empirical results from a study conducted with biology undergraduate students, where we demonstrate that asking them to "dissect" out specific conceptual structures from an already built 3D physical model leads to a significant improvement in performance than asking them to build the 3D model from simpler components. Using questionnaires to measure understanding both before and after model-based interventions for two cohorts of students, we find that both the "builders" and the "dissectors" improve in the post-test, but it is the latter group who show statistically significant improvement. These results, in addition to the intrinsic time-efficiency of "model dissection," suggest that it could be a valuable pedagogical tool. PMID:26712513

  9. Accelerator physics and modeling: Proceedings

    SciTech Connect

    Parsa, Z.

    1991-01-01

    This report contains papers on the following topics: Physics of high brightness beams; radio frequency beam conditioner for fast-wave free-electron generators of coherent radiation; wake-field and space-charge effects on high brightness beams. Calculations and measured results for BNL-ATF; non-linear orbit theory and accelerator design; general problems of modeling for accelerators; development and application of dispersive soft ferrite models for time-domain simulation; and bunch lengthening in the SLC damping rings.

  10. Accelerator physics and modeling: Proceedings

    SciTech Connect

    Parsa, Z.

    1991-12-31

    This report contains papers on the following topics: Physics of high brightness beams; radio frequency beam conditioner for fast-wave free-electron generators of coherent radiation; wake-field and space-charge effects on high brightness beams. Calculations and measured results for BNL-ATF; non-linear orbit theory and accelerator design; general problems of modeling for accelerators; development and application of dispersive soft ferrite models for time-domain simulation; and bunch lengthening in the SLC damping rings.

  11. Investigating Electroweak Physics at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Tien, Pin-Ju

    The basic principle of naturalness has driven the majority of the Large Hadron Collider (LHC) program, but so far all searches for new physics beyond the Standard Model (SM) have come up empty. On the other hand, a few existing measurements of SM processes contain interesting anomalies, for instance in the measurement of the WW cross section. The deviation of WW cross section was seen both at ATLAS and CMS and both at 7 and 8 TeV. The discrepancy also became larger at 8 TeV. Combined results with LHC 7 TeV and 8 TeV implies around a three sigma deviation from the SM NLO calculation. This allows for the possibility of new physics with mass scales very close to the Electroweak Scale. We show that the addition of physics beyond the SM at electroweak scale can improve the agreement with the data. In particular supersymmetric models involving charginos, stops and sleptons all provide better fits with the data. In the case of models of sleptons that agree better with the WW data, they can also explain dark matter and the (g-2) anomaly. Furthermore, we show that there are several different classes of stop driven scenarios that not only evade all direct searches, but improve the agreement with the data in the SM measurement of the WW cross section. We also demonstrate that even if these anomalies are not due to new physics, the WW channel can also be used to derive new exclusion limits which are more powerful than existing results using the same ATLAS and CMS datasets. By examining the differential WW cross section we show that the gap between LHC and LEP exclusions can be start to be closed. In particular, we lay out a program under which the diffcult to search for regions of new physics models with large SM backgrounds can be investigated.

  12. Waste glass melter numerical and physical modeling

    SciTech Connect

    Eyler, L.L.; Peters, R.D.; Lessor, D.L.; Lowery, P.S.; Elliott, M.L.

    1991-10-01

    Results of physical and numerical simulation modeling of high-level liquid waste vitrification melters are presented. Physical modeling uses simulant fluids in laboratory testing. Visualization results provide insight into convective melt flow patterns from which information is derived to support performance estimation of operating melters and data to support numerical simulation. Numerical simulation results of several melter configurations are presented. These are in support of programs to evaluate melter operation characteristics and performance. Included are investigations into power skewing and alternating current electric field phase angle in a dual electrode pair reference design and bi-modal convective stability in an advanced design. 9 refs., 9 figs., 1 tab.

  13. Review of Some Promising Fractional Physical Models

    NASA Astrophysics Data System (ADS)

    Tarasov, Vasily E.

    2013-04-01

    Fractional dynamics is a field of study in physics and mechanics investigating the behavior of objects and systems that are characterized by power-law nonlocality, power-law long-term memory or fractal properties by using integrations and differentiation of non-integer orders, i.e., by methods in the fractional calculus. This paper is a review of physical models that look very promising for future development of fractional dynamics. We suggest a short introduction to fractional calculus as a theory of integration and differentiation of noninteger order. Some applications of integro-differentiations of fractional orders in physics are discussed. Models of discrete systems with memory, lattice with long-range inter-particle interaction, dynamics of fractal media are presented. Quantum analogs of fractional derivatives and model of open nano-system systems with memory are also discussed.

  14. Physical and mathematical cochlear models

    NASA Astrophysics Data System (ADS)

    Lim, Kian-Meng

    2000-10-01

    The cochlea is an intricate organ in the inner ear responsible for our hearing. Besides acting as a transducer to convert mechanical sound vibrations to electrical neural signals, the cochlea also amplifies and separates the sound signal into its spectral components for further processing in the brain. It operates over a broad-band of frequency and a huge dynamic range of input while maintaining a low power consumption. The present research takes the approach of building cochlear models to study and understand the underlying mechanics involved in the functioning of the cochlea. Both physical and mathematical models of the cochlea are constructed. The physical model is a first attempt to build a life- sized replica of the human cochlea using advanced micro- machining techniques. The model takes a modular design, with a removable silicon-wafer based partition membrane encapsulated in a plastic fluid chamber. Preliminary measurements in the model are obtained and they compare roughly with simulation results. Parametric studies on the design parameters of the model leads to an improved design of the model. The studies also revealed that the width and orthotropy of the basilar membrane in the cochlea have significant effects on the sharply tuned responses observed in the biological cochlea. The mathematical model is a physiologically based model that includes three-dimensional viscous fluid flow and a tapered partition with variable properties along its length. A hybrid asymptotic and numerical method provides a uniformly valid and efficient solution to the short and long wave regions in the model. Both linear and non- linear activity are included in the model to simulate the active cochlea. The mathematical model has successfully reproduced many features of the response in the biological cochlea, as observed in experiment measurements performed on animals. These features include sharply tuned frequency responses, significant amplification with inclusion of activity

  15. The Role of Various Curriculum Models on Physical Activity Levels

    ERIC Educational Resources Information Center

    Culpepper, Dean O.; Tarr, Susan J.; Killion, Lorraine E.

    2011-01-01

    Researchers have suggested that physical education curricula can be highly effective in increasing physical activity levels at school (Sallis & Owen, 1999). The purpose of this study was to investigate the impact of various curriculum models on physical activity. Total steps were measured on 1,111 subjects and three curriculum models were studied…

  16. Investigating correlation between legal and physical property: possibilities and constraints

    NASA Astrophysics Data System (ADS)

    Dimopoulou, E.; Kitsakis, D.; Tsiliakou, E.

    2015-06-01

    Contemporary urban environment is characterized by complexity and mixed use of space, in which overlapping land parcels and different RRRs (Rights, Restrictions and Responsibilities) are frequent phenomena. Internationally, real property legislation either focuses on surface property or has introduced individual 3D real property units. The former approach merely accommodates issues related to subdivision, expropriation and transactions on part of the real property above or below surface, while the latter provides for defining and registering 3D real property units. National laws require two-dimensional real property descriptions and only a limited number of jurisdictions provide for threedimensional data presentation and recording. International awareness on 3D Cadastre may be apparent through the proposals for transition of existing cadastral systems to 3D along with legal amendments improving national 3D Cadastre legislation. Concurrently the use of appropriate data sources and the correct depiction of 3D property units' boundaries and spatial relationships need to be addressed. Spatial relations and constraints amongst real world objects could be modeled geometrically and topologically utilizing numerous modeling tools, e.g. CityGML, BIM and further sophisticated 3D software or by adapting international standards, e.g. LADM. A direct correlation between legal and physical property should be based on consistent geometry between physical and legal space, improving the accuracy that legal spaces' volumes or locations are defined. To address these issues, this paper investigates correlation possibilities and constraints between legal and physical space of typical 3D property cases. These cases comprise buildings or their interior spaces with mixed use, as well as complex structures described by explicit facade patterns, generated by procedural or by BIM ready 3D models. The 3D models presented are evaluated, regarding compliancy to physical or legal reality.

  17. Combined Experimental and Numerical Investigations into Laser Propulsion Engineering Physics

    NASA Astrophysics Data System (ADS)

    Kenoyer, David Adam

    The RPI pulsed Laser Propulsion (LP) research effort focuses on the future application of launching nano- and micro-satellites (1-10 kg payloads) into Low Earth Orbit (LEO), using a remote Ground Based Laser (GBL) power station to supply the required energy for flight. This research program includes both experimental and numerical studies investigating the propulsive performance of several engine geometries (constituting a lightcraft family). Using the Lumonics twin K-922m TEA pulsed laser system, axial and lateral thrust, C m, Isp, and η measurements were made for these engine geometries, examining the effects of several critical factors including: engine orientation (e.g. lateral and angular offset), laser pulse energy, pulse repetition frequency, pulse duration, propellant type, and engine size-scaling effects. Investigation into the origins of lateral "beam riding" forces was of particular interest. Lateral impulse measurements and high speed Schlieren photography were utilized to provide an understanding of laser beam-riding/propulsive physics. The acquired lightcraft database was used to further develop an existing 7-Degree Of Freedom (DOF) flight dynamics model extensively calibrated against 16 actual trajectories of small scale model lightcraft flown at White Sands Missile Range, NM on a 10 kW pulsed CO2 laser called PLVTS. The full system 7-DOF model is comprised of updated individual aerodynamics, engine, laser beam propagation, variable vehicle inertia, reaction controls system, and dynamics models, integrated to represent all major phenomena in a consistent framework. This flight dynamics model and associated 7-DOF code provide a physics-based predictive tool for basic research investigations into laser launched lightcraft for suborbital and orbital missions. Simulations were performed to demonstrate the flight capabilities of each engine geometry using the updated lightcraft propulsion database, the results of which further demonstrate that autonomous

  18. Levitation Force Investigation of Bulk HTSC Above Halbach PMG with Different Cross-Section Physical Dimensions by 3D-Modeling Numerical Method

    NASA Astrophysics Data System (ADS)

    Lu, Yiyun; Liu, Guoliang; Qin, Yujie

    2014-10-01

    The levitation force of a bulk high temperature superconductor (HTSC) over Halbach permanent magnet guideways (PMG) with different cross-section configuration is studied by numerical method. The Halbach PMG is composed of three host permanent magnets (HPMs) and two slave permanent magnets (SPMs). One cylindrical bulk HTSC with a diameter of 30 mm and height of 15 mm is used. The 3D-modeling is formulated by the H-method. The numerical resolving codes are practiced using finite element method (FEM). The E-J power law is used to describe the electric current nonlinear characteristics of bulk HTSC. By the method, the influence of the cross-section physical dimensions of Halbach PMG on the levitation forces of bulk HTSC levitated above the PMG is studied. The simulation results show that increasing the width of SPM ( can enhance the bulk HTSC levitation performance immediately under the condition of keeping the ratio of ( : the width of HPM) to between 1.6 and 1.8, the ratio of td (the height of the PMG) to between 1.2 and 1.4. By the method, the bulk HTSC better levitation performance can be expected.

  19. A gender study investigating physics self-efficacy

    NASA Astrophysics Data System (ADS)

    Sawtelle, Vashti

    The underrepresentation of women in physics has been well documented and a source of concern for both policy makers and educators. My dissertation focuses on understanding the role self-efficacy plays in retaining students, particularly women, in introductory physics. I use an explanatory mixed methods approach to first investigate quantitatively the influence of self-efficacy in predicting success and then to qualitatively explore the development of self-efficacy. In the initial quantitative studies, I explore the utility of self-efficacy in predicting the success of introductory physics students, both women and men. Results indicate that self-efficacy is a significant predictor of success for all students. I then disaggregate the data to examine how self-efficacy develops differently for women and men in the introductory physics course. Results show women rely on different sources of self-efficacy than do men, and that a particular instructional environment, Modeling Instruction, has a positive impact on these sources of self-efficacy. In the qualitative phase of the project, this dissertation focuses on the development of self-efficacy. Using the qualitative tool of microanalysis, I introduce a methodology for understanding how self-efficacy develops moment-by-moment using the lens of self-efficacy opportunities. I then use the characterizations of self-efficacy opportunities to focus on a particular course environment and to identify and describe a mechanism by which Modeling Instruction impacts student self-efficacy. Results indicate that the emphasizing the development and deployment of models affords opportunities to impact self-efficacy. The findings of this dissertation indicate that introducing key elements into the classroom, such as cooperative group work, model development and deployment, and interaction with the instructor, create a mechanism by which instructors can impact the self-efficacy of their students. Results from this study indicate that

  20. Physical modeling of the piano

    NASA Astrophysics Data System (ADS)

    Giordano, N.; Jiang, M.

    2003-10-01

    Over the past several years, this project has been aimed at constructing a physical model of the piano. The goal is to use Newton's laws to describe the motion of the hammers, strings, soundboard, and surrounding air, and thereby calculate the sound produced by the instrument entirely from first principles. The structure of the model is described, along with experiments that have provided essential tests and guidance to the calculations. The state of the model and, especially, how this work can lead to new insights and understanding into the piano are discussed. In many cases the work and the specific questions addressed along the way have followed paths initially inspired and developed by Gabriel Weinreich. [Work supported by NSF.

  1. Simulated, Emulated, and Physical Investigative Analysis (SEPIA) of networked systems.

    SciTech Connect

    Burton, David P.; Van Leeuwen, Brian P.; McDonald, Michael James; Onunkwo, Uzoma A.; Tarman, Thomas David; Urias, Vincent E.

    2009-09-01

    This report describes recent progress made in developing and utilizing hybrid Simulated, Emulated, and Physical Investigative Analysis (SEPIA) environments. Many organizations require advanced tools to analyze their information system's security, reliability, and resilience against cyber attack. Today's security analysis utilize real systems such as computers, network routers and other network equipment, computer emulations (e.g., virtual machines) and simulation models separately to analyze interplay between threats and safeguards. In contrast, this work developed new methods to combine these three approaches to provide integrated hybrid SEPIA environments. Our SEPIA environments enable an analyst to rapidly configure hybrid environments to pass network traffic and perform, from the outside, like real networks. This provides higher fidelity representations of key network nodes while still leveraging the scalability and cost advantages of simulation tools. The result is to rapidly produce large yet relatively low-cost multi-fidelity SEPIA networks of computers and routers that let analysts quickly investigate threats and test protection approaches.

  2. Cabin Environment Physics Risk Model

    NASA Technical Reports Server (NTRS)

    Mattenberger, Christopher J.; Mathias, Donovan Leigh

    2014-01-01

    This paper presents a Cabin Environment Physics Risk (CEPR) model that predicts the time for an initial failure of Environmental Control and Life Support System (ECLSS) functionality to propagate into a hazardous environment and trigger a loss-of-crew (LOC) event. This physics-of failure model allows a probabilistic risk assessment of a crewed spacecraft to account for the cabin environment, which can serve as a buffer to protect the crew during an abort from orbit and ultimately enable a safe return. The results of the CEPR model replace the assumption that failure of the crew critical ECLSS functionality causes LOC instantly, and provide a more accurate representation of the spacecraft's risk posture. The instant-LOC assumption is shown to be excessively conservative and, moreover, can impact the relative risk drivers identified for the spacecraft. This, in turn, could lead the design team to allocate mass for equipment to reduce overly conservative risk estimates in a suboptimal configuration, which inherently increases the overall risk to the crew. For example, available mass could be poorly used to add redundant ECLSS components that have a negligible benefit but appear to make the vehicle safer due to poor assumptions about the propagation time of ECLSS failures.

  3. Topos models for physics and topos theory

    SciTech Connect

    Wolters, Sander

    2014-08-15

    What is the role of topos theory in the topos models for quantum theory as used by Isham, Butterfield, Döring, Heunen, Landsman, Spitters, and others? In other words, what is the interplay between physical motivation for the models and the mathematical framework used in these models? Concretely, we show that the presheaf topos model of Butterfield, Isham, and Döring resembles classical physics when viewed from the internal language of the presheaf topos, similar to the copresheaf topos model of Heunen, Landsman, and Spitters. Both the presheaf and copresheaf models provide a “quantum logic” in the form of a complete Heyting algebra. Although these algebras are natural from a topos theoretic stance, we seek a physical interpretation for the logical operations. Finally, we investigate dynamics. In particular, we describe how an automorphism on the operator algebra induces a homeomorphism (or isomorphism of locales) on the associated state spaces of the topos models, and how elementary propositions and truth values transform under the action of this homeomorphism. Also with dynamics the focus is on the internal perspective of the topos.

  4. Equity investigation of attitudinal shifts in introductory physics

    NASA Astrophysics Data System (ADS)

    Traxler, Adrienne; Brewe, Eric

    2015-12-01

    We report on seven years of attitudinal data using the Colorado Learning Attitudes about Science Survey from University Modeling Instruction (UMI) sections of introductory physics at Florida International University. University Modeling Instruction is a curricular and pedagogical transformation of introductory university physics that engages students in building and testing conceptual models in an integrated lab and lecture learning environment. This work expands upon previous studies that reported consistently positive attitude shifts in UMI courses; here, we disaggregate the data by gender and ethnicity to look for any disparities in the pattern of favorable shifts. We find that women and students from statistically underrepresented ethnic groups have gains that are comparable to those of men and students from well-represented ethnic groups on this attitudinal measure, and that this result holds even when interaction effects of gender and ethnicity are included. We conclude with suggestions for future work in UMI courses and for attitudinal equity investigations generally. We encourage researchers to expand their scope beyond simple performance gaps when considering equity concerns, and to avoid relying on a single measure to evaluate student success. Finally, we conjecture that students' social and academic networks are one means by which attitudinal and efficacy beliefs about the course are propagated.

  5. A Multivariate Model of Physics Problem Solving

    ERIC Educational Resources Information Center

    Taasoobshirazi, Gita; Farley, John

    2013-01-01

    A model of expertise in physics problem solving was tested on undergraduate science, physics, and engineering majors enrolled in an introductory-level physics course. Structural equation modeling was used to test hypothesized relationships among variables linked to expertise in physics problem solving including motivation, metacognitive planning,…

  6. Equity Investigation of Attitudinal Shifts in Introductory Physics

    ERIC Educational Resources Information Center

    Traxler, Adrienne; Brewe, Eric

    2015-01-01

    We report on seven years of attitudinal data using the Colorado Learning Attitudes about Science Survey from University Modeling Instruction (UMI) sections of introductory physics at Florida International University. University Modeling Instruction is a curricular and pedagogical transformation of introductory university physics that engages…

  7. A Gender Study Investigating Physics Self-Efficacy

    ERIC Educational Resources Information Center

    Sawtelle, Vashti

    2011-01-01

    The underrepresentation of women in physics has been well documented and a source of concern for both policy makers and educators. My dissertation focuses on understanding the role self-efficacy plays in retaining students, particularly women, in introductory physics. I use an explanatory mixed methods approach to first investigate quantitatively…

  8. Development and assessment of a physics-based simulation model to investigate residential PM2.5 infiltration across the US housing stock

    EPA Science Inventory

    The Lawrence Berkeley National Laboratory Population Impact Assessment Modeling Framework (PIAMF) was expanded to enable determination of indoor PM2.5 concentrations and exposures in a set of 50,000 homes representing the US housing stock. A mass-balance model is used to calculat...

  9. Physics modeling support contract: Final report

    SciTech Connect

    Not Available

    1987-09-30

    This document is the final report for the Physics Modeling Support contract between TRW, Inc. and the Lawrence Livermore National Laboratory for fiscal year 1987. It consists of following projects: TIBER physics modeling and systems code development; advanced blanket modeling task; time dependent modeling; and free electron maser for TIBER II.

  10. Model Formulation for Physics Problem Solving. Draft.

    ERIC Educational Resources Information Center

    Novak, Gordon S., Jr.

    The major task in solving a physics problem is to construct an appropriate model of the problem in terms of physical principles. The functions performed by such a model, the information which needs to be represented, and the knowledge used in selecting and instantiating an appropriate model are discussed. An example of a model for a mechanics…

  11. Evaluating a Model of Youth Physical Activity

    PubMed Central

    Heitzler, Carrie D.; Lytle, Leslie A.; Erickson, Darin J.; Barr-Anderson, Daheia; Sirard, John R.; Story, Mary

    2011-01-01

    Objective To explore the relationship between social influences, self-efficacy, enjoyment, and barriers and physical activity. Methods Structural equation modeling examined relationships between parent and peer support, parent physical activity, individual perceptions, and objectively measured physical activity using accelerometers among a sample of youth aged 10–17 years (N=720). Results Peer support, parent physical activity, and perceived barriers were directly related to youth activity. The proposed model accounted for 14.7% of the variance in physical activity. Conclusions The results demonstrate a need to further explore additional individual, social, and environmental factors that may influence youth’s regular participation in physical activity. PMID:20524889

  12. Physical modeling of Tibetan bowls

    NASA Astrophysics Data System (ADS)

    Antunes, Jose; Inacio, Octavio

    2001-05-01

    Tibetan bowls produce rich penetrating sounds, used in musical contexts and to induce a state of relaxation for meditation or therapy purposes. To understand the dynamics of these instruments under impact and rubbing excitation, we developed a simulation method based on the modal approach, following our previous papers on physical modeling of plucked/bowed strings and impacted/bowed bars. This technique is based on a compact representation of the system dynamics, in terms of the unconstrained bowl modes. Nonlinear contact/friction interaction forces, between the exciter (puja) and the bowl, are computed at each time step and projected on the bowl modal basis, followed by step integration of the modal equations. We explore the behavior of two different-sized bowls, for extensive ranges of excitation conditions (contact/friction parameters, normal force, and tangential puja velocity). Numerical results and experiments show that various self-excited motions may arise depending on the playing conditions and, mainly, on the contact/friction interaction parameters. Indeed, triggering of a given bowl modal frequency mainly depends on the puja material. Computed animations and experiments demonstrate that self-excited modes spin, following the puja motion. Accordingly, the sensed pressure field pulsates, with frequency controlled by the puja spinning velocity and the spatial pattern of the singing mode.

  13. A qualitative model of physical fields

    SciTech Connect

    Lundell, M.

    1996-12-31

    A qualitative model of the spatio-temporal behaviour of distributed parameter systems based on physical fields is presented. Field-based models differ from the object-based models normally used in qualitative physics by treating parameters as continuous entities instead of as attributes of discrete objects. This is especially suitable for natural physical systems, e.g. in ecology. The model is divided into a static and a dynamic part. The static model describes the distribution of each parameter as a qualitative physical field. Composite fields are constructed from intersection models of pairs of fields. The dynamic model describes processes acting on the fields, and qualitative relationships between parameters. Spatio-temporal behaviour is modelled by interacting temporal processes, influencing single points in space, and spatial processes that gradually spread temporal processes over space. We give an example of a qualitative model of a natural physical system and discuss the ambiguities that arise during simulation.

  14. NUMERICAL MODELING OF FINE SEDIMENT PHYSICAL PROCESSES.

    USGS Publications Warehouse

    Schoellhamer, David H.

    1985-01-01

    Fine sediment in channels, rivers, estuaries, and coastal waters undergo several physical processes including flocculation, floc disruption, deposition, bed consolidation, and resuspension. This paper presents a conceptual model and reviews mathematical models of these physical processes. Several general fine sediment models that simulate some of these processes are reviewed. These general models do not directly simulate flocculation and floc disruption, but the conceptual model and existing functions are shown to adequately model these two processes for one set of laboratory data.

  15. From metallurgy to modelling of electrical steels: A multiple approach to their behaviour and use based on physics and experimental investigations

    NASA Astrophysics Data System (ADS)

    Cornut, B.; Kedous-Lebouc, A.; Waeckerlé, Th.

    1996-07-01

    Research on SiFe is a busy field which corresponds to the main soft magnetic materials interests of the Laboratoire d'Electrotechnique de Grenoble. Three mutually enriched areas are being explored: metallurgical research towards the production of cube textured sheets, instrumentation research allowing precise measurements of magnetic properties under extreme conditions, and models of magnetization vectorial laws or loss prediction to be included in computer aided design.

  16. Guest investigator program study: Physics of equatorial plasma bubbles

    NASA Technical Reports Server (NTRS)

    Tsunoda, Roland T.

    1994-01-01

    Plasma bubbles are large-scale (10 to 100 km) depletions in plasma density found in the night-time equatorial ionosphere. Their formation has been found to entail the upward transport of plasma over hundreds of kilometers in altitude, suggesting that bubbles play significant roles in the physics of many of the diverse and unique features found in the low-latitude ionosphere. In the simplest scenario, plasma bubbles appear first as perturbations in the bottomside F layer, which is linearly unstable to the gravitationally driven Rayleigh-Taylor instability. Once initiated, bubbles develop upward through the peak of the F layer into its topside (sometimes to altitudes in excess of 1000 km), a behavior predicted by the nonlinear form of the same instability. While good general agreement has been found between theory and observations, little is known about the detailed physics associated with plasma bubbles. Our research activity centered around two topics: the shape of plasma bubbles and associated electric fields, and the day-to-day variability in the occurrence of plasma bubbles. The first topic was pursued because of a divergence in view regarding the nonlinear physics associated with plasma bubble development. While the development of perturbations in isodensity contours in the bottomside F layer into plasma bubbles is well accepted, some believed bubbles to be cylinder-like closed regions of depleted plasma density that floated upward leaving a turbulent wake behind them (e.g., Woodman and LaHoz, 1976; Ott, 1978; Kelley and Ott, 1978). Our results, summarized in a paper submitted to the Journal of Geophysical Research, consisted of incoherent scatter radar measurements that showed unambiguously that the depleted region is wedgelike and not cylinderlike, and a case study and modeling of SM-D electric field instrument (EFI) measurements that showed that the absence of electric-field perturbations outside the plasma-depleted region is a distinct signature of wedge

  17. Physics models of centriole replication.

    PubMed

    Cheng, Kang; Zou, Changhua

    2006-01-01

    Our previous pre-clinic experimental results have showed that the epithelialization can be enhanced by the externally applied rectangular pulsed electrical current stimulation (RPECS). The results are clinically significant for patients, especially for those difficult patients whose skin wounds need long periods to heal. However, the results also raise questions: How does the RPECS accelerate the epithelium cell proliferation? To answer these questions, we have previously developed several models for animal cells, in a view of physics, to explain mechanisms of mitosis and cytokinesis at a cellular level, and separation of nucleotide sequences and the unwinding of a double helix during DNA replication at a bio-molecular level. In this paper, we further model the mechanism of centriole replication during a natural and normal mitosis and cytokinesis to explore the mechanism of epithelialization enhanced with the externally applied RPECS at a bio-molecular level. Our models suggest: (1) Centriole replication is an information flowing. The direction of the information flowing is from centrioles to centrioles based on a cylindrical template of 9 x 3 protein microtubules (MTs) pattern. (2) A spontaneous and strong electromagnetic field (EMF) force is a pushing force that separates a mother and a daughter centrioles in centrosomes or in cells, while a pulling force of interacting fibers and pericentriolar materials delivers new babies. The newly born babies inherit the pattern information from their mother(s) and grow using microtubule fragments that come through the centrosome pores. A daughter centriole is always born and grows along stronger EMF. The EMF mostly determines centrioles positions and plays key role in centriole replication. We also hypothesize that the normal centriole replication could not been disturbed in centrosome in the epithelium cells by our RPECS, because the centrioles have two non-conducting envelope (cell and centrosome membranes), that protect

  18. Multi-physics modelling contributions to investigate the atmospheric cosmic rays on the single event upset sensitivity along the scaling trend of CMOS technologies.

    PubMed

    Hubert, G; Regis, D; Cheminet, A; Gatti, M; Lacoste, V

    2014-10-01

    Particles originating from primary cosmic radiation, which hit the Earth's atmosphere give rise to a complex field of secondary particles. These particles include neutrons, protons, muons, pions, etc. Since the 1980s it has been known that terrestrial cosmic rays can penetrate the natural shielding of buildings, equipment and circuit package and induce soft errors in integrated circuits. Recently, research has shown that commercial static random access memories are now so small and sufficiently sensitive that single event upsets (SEUs) may be induced from the electronic stopping of a proton. With continued advancements in process size, this downward trend in sensitivity is expected to continue. Then, muon soft errors have been predicted for nano-electronics. This paper describes the effects in the specific cases such as neutron-, proton- and muon-induced SEU observed in complementary metal-oxide semiconductor. The results will allow investigating the technology node sensitivity along the scaling trend.

  19. Multi-physics modelling contributions to investigate the atmospheric cosmic rays on the single event upset sensitivity along the scaling trend of CMOS technologies.

    PubMed

    Hubert, G; Regis, D; Cheminet, A; Gatti, M; Lacoste, V

    2014-10-01

    Particles originating from primary cosmic radiation, which hit the Earth's atmosphere give rise to a complex field of secondary particles. These particles include neutrons, protons, muons, pions, etc. Since the 1980s it has been known that terrestrial cosmic rays can penetrate the natural shielding of buildings, equipment and circuit package and induce soft errors in integrated circuits. Recently, research has shown that commercial static random access memories are now so small and sufficiently sensitive that single event upsets (SEUs) may be induced from the electronic stopping of a proton. With continued advancements in process size, this downward trend in sensitivity is expected to continue. Then, muon soft errors have been predicted for nano-electronics. This paper describes the effects in the specific cases such as neutron-, proton- and muon-induced SEU observed in complementary metal-oxide semiconductor. The results will allow investigating the technology node sensitivity along the scaling trend. PMID:24500239

  20. Statistical physical models of cellular motility

    NASA Astrophysics Data System (ADS)

    Banigan, Edward J.

    Cellular motility is required for a wide range of biological behaviors and functions, and the topic poses a number of interesting physical questions. In this work, we construct and analyze models of various aspects of cellular motility using tools and ideas from statistical physics. We begin with a Brownian dynamics model for actin-polymerization-driven motility, which is responsible for cell crawling and "rocketing" motility of pathogens. Within this model, we explore the robustness of self-diffusiophoresis, which is a general mechanism of motility. Using this mechanism, an object such as a cell catalyzes a reaction that generates a steady-state concentration gradient that propels the object in a particular direction. We then apply these ideas to a model for depolymerization-driven motility during bacterial chromosome segregation. We find that depolymerization and protein-protein binding interactions alone are sufficient to robustly pull a chromosome, even against large loads. Next, we investigate how forces and kinetics interact during eukaryotic mitosis with a many-microtubule model. Microtubules exert forces on chromosomes, but since individual microtubules grow and shrink in a force-dependent way, these forces lead to bistable collective microtubule dynamics, which provides a mechanism for chromosome oscillations and microtubule-based tension sensing. Finally, we explore kinematic aspects of cell motility in the context of the immune system. We develop quantitative methods for analyzing cell migration statistics collected during imaging experiments. We find that during chronic infection in the brain, T cells run and pause stochastically, following the statistics of a generalized Levy walk. These statistics may contribute to immune function by mimicking an evolutionarily conserved efficient search strategy. Additionally, we find that naive T cells migrating in lymph nodes also obey non-Gaussian statistics. Altogether, our work demonstrates how physical

  1. High-Energy Physics Outstanding Junior Investigating Program

    SciTech Connect

    Kaplan, David, E.

    2009-10-12

    Throughout the past five years I have worked to uncover what physics lies beyond that of the standard model. My main focus in the first two and a half years has been to understand physics at the electroweak scale, and to a lesser extent understand the relationship between particle physics and cosmology. My final two and a half years was spent on studying the feasibility of discovering “non-standard” models of electroweak physics at hadron colliders, working in close contact with experimentalists at the Tevatron and the LHC. My biggest successes during this period has been both in electroweak physics – expanding our understanding of the Higgs sector in supersymmetric theories and ultraviolet completions of little Higgs theories – and in collider physics – discovering a method for identifying high momentum top quarks and realizing the potential for LHCb to discover some versions of supersymmetry. I have also made some progress towards a particle physics/effective field theory solution of the cosmological constant problem.

  2. Evaluating a Model of Youth Physical Activity

    ERIC Educational Resources Information Center

    Heitzler, Carrie D.; Lytle, Leslie A.; Erickson, Darin J.; Barr-Anderson, Daheia; Sirard, John R.; Story, Mary

    2010-01-01

    Objective: To explore the relationship between social influences, self-efficacy, enjoyment, and barriers and physical activity. Methods: Structural equation modeling examined relationships between parent and peer support, parent physical activity, individual perceptions, and objectively measured physical activity using accelerometers among a…

  3. Modelling biological complexity: a physical scientist's perspective.

    PubMed

    Coveney, Peter V; Fowler, Philip W

    2005-09-22

    We discuss the modern approaches of complexity and self-organization to understanding dynamical systems and how these concepts can inform current interest in systems biology. From the perspective of a physical scientist, it is especially interesting to examine how the differing weights given to philosophies of science in the physical and biological sciences impact the application of the study of complexity. We briefly describe how the dynamics of the heart and circadian rhythms, canonical examples of systems biology, are modelled by sets of nonlinear coupled differential equations, which have to be solved numerically. A major difficulty with this approach is that all the parameters within these equations are not usually known. Coupled models that include biomolecular detail could help solve this problem. Coupling models across large ranges of length- and time-scales is central to describing complex systems and therefore to biology. Such coupling may be performed in at least two different ways, which we refer to as hierarchical and hybrid multiscale modelling. While limited progress has been made in the former case, the latter is only beginning to be addressed systematically. These modelling methods are expected to bring numerous benefits to biology, for example, the properties of a system could be studied over a wider range of length- and time-scales, a key aim of systems biology. Multiscale models couple behaviour at the molecular biological level to that at the cellular level, thereby providing a route for calculating many unknown parameters as well as investigating the effects at, for example, the cellular level, of small changes at the biomolecular level, such as a genetic mutation or the presence of a drug. The modelling and simulation of biomolecular systems is itself very computationally intensive; we describe a recently developed hybrid continuum-molecular model, HybridMD, and its associated molecular insertion algorithm, which point the way towards the

  4. Modelling biological complexity: a physical scientist's perspective

    PubMed Central

    Coveney, Peter V; Fowler, Philip W

    2005-01-01

    We discuss the modern approaches of complexity and self-organization to understanding dynamical systems and how these concepts can inform current interest in systems biology. From the perspective of a physical scientist, it is especially interesting to examine how the differing weights given to philosophies of science in the physical and biological sciences impact the application of the study of complexity. We briefly describe how the dynamics of the heart and circadian rhythms, canonical examples of systems biology, are modelled by sets of nonlinear coupled differential equations, which have to be solved numerically. A major difficulty with this approach is that all the parameters within these equations are not usually known. Coupled models that include biomolecular detail could help solve this problem. Coupling models across large ranges of length- and time-scales is central to describing complex systems and therefore to biology. Such coupling may be performed in at least two different ways, which we refer to as hierarchical and hybrid multiscale modelling. While limited progress has been made in the former case, the latter is only beginning to be addressed systematically. These modelling methods are expected to bring numerous benefits to biology, for example, the properties of a system could be studied over a wider range of length- and time-scales, a key aim of systems biology. Multiscale models couple behaviour at the molecular biological level to that at the cellular level, thereby providing a route for calculating many unknown parameters as well as investigating the effects at, for example, the cellular level, of small changes at the biomolecular level, such as a genetic mutation or the presence of a drug. The modelling and simulation of biomolecular systems is itself very computationally intensive; we describe a recently developed hybrid continuum-molecular model, HybridMD, and its associated molecular insertion algorithm, which point the way towards the

  5. Investigating physics teaching and learning in a university setting

    NASA Astrophysics Data System (ADS)

    Guisasola, Jenaro; De Cock, Mieke; Kanim, Stephen; Ivanjek, Lana; Zuza, Kristina; Bollen, Laurens; van Kampen, Paul

    2016-05-01

    Most of the initiatives taken by the European Community and by other countries internationally in the field of science education focus on elementary and secondary levels of education, and relatively few reports have analysed the state of science education in higher education. However, research in science education, and in particular in physics education, has shown repeatedly that the way teachers teach in elementary and secondary school is strongly influenced by their own prior experience as university students. The education that future professionals, such as scientists, engineers and science teachers, receive at the university is worthy of study, because it allows us to investigate student learning relatively independently of developmental issues, and because of the more rigorous treatment of physics topics at the university level. For these reasons, it seems appropriate to identify, analyse and provide solutions to the problems of teaching and learning related to the university physics curriculum. In this symposium, we present examples of physics education research from different countries that is focused on physics topics

  6. Are Physical Education Majors Models for Fitness?

    ERIC Educational Resources Information Center

    Kamla, James; Snyder, Ben; Tanner, Lori; Wash, Pamela

    2012-01-01

    The National Association of Sport and Physical Education (NASPE) (2002) has taken a firm stance on the importance of adequate fitness levels of physical education teachers stating that they have the responsibility to model an active lifestyle and to promote fitness behaviors. Since the NASPE declaration, national initiatives like Let's Move…

  7. Modeling Physics with Easy Java Simulations

    ERIC Educational Resources Information Center

    Christian, Wolfgang; Esquembre, Francisco

    2007-01-01

    Modeling has been shown to correct weaknesses of traditional instruction by engaging students in the design of physical models to describe, explain, and predict phenomena. Although the modeling method can be used without computers, the use of computers allows students to study problems that are difficult and time consuming, to visualize their…

  8. The trinucleons: Physical observables and model properties

    SciTech Connect

    Gibson, B.F.

    1992-01-01

    Our progress in understanding the properties of {sup 3}H and {sup 3}He in terms of a nonrelativistic Hamiltonian picture employing realistic nuclear forces is reviewed. Trinucleon model properties are summarized for a number of contemporary force models, and predictions for physical observables are presented. Disagreement between theoretical model results and experimental results are highlighted.

  9. The trinucleons: Physical observables and model properties

    SciTech Connect

    Gibson, B.F.

    1992-05-01

    Our progress in understanding the properties of {sup 3}H and {sup 3}He in terms of a nonrelativistic Hamiltonian picture employing realistic nuclear forces is reviewed. Trinucleon model properties are summarized for a number of contemporary force models, and predictions for physical observables are presented. Disagreement between theoretical model results and experimental results are highlighted.

  10. Investigation of physical parameters in stellar flares observed by GINGA

    NASA Technical Reports Server (NTRS)

    Stern, Robert A.

    1994-01-01

    This program involves analysis and interpretation of results from GINGA Large Area Counter (LAC) observations from a group of large stellar X-ray flares. All LAC data are re-extracted using the standard Hayashida method of LAC background subtraction and analyzed using various models available with the XSPEC spectral fitting program.Temperature-emission measure histories are available for a total of 5 flares observed by GINGA. These will be used to compare physical parameters of these flares with solar and stellar flare models.

  11. Investigation of physical parameters in stellar flares observed by GINGA

    NASA Technical Reports Server (NTRS)

    Stern, Robert A.

    1994-01-01

    This program involves analysis and interpretation of results from GINGA Large Area Counter (LAC) observations from a group of large stellar x-ray flares. All LAC data are re-extracted using the standard Hayashida method of LAC background subtraction and analyzed using various models available with the XSPEC spectral fitting program. Temperature-emission measure histories are available for a total of 5 flares observed by GINGA. These will be used to compare physical parameters of these flares with solar and stellar flare models.

  12. Physics of the Quark Model

    ERIC Educational Resources Information Center

    Young, Robert D.

    1973-01-01

    Discusses the charge independence, wavefunctions, magnetic moments, and high-energy scattering of hadrons on the basis of group theory and nonrelativistic quark model with mass spectrum calculated by first-order perturbation theory. The presentation is explainable to advanced undergraduate students. (CC)

  13. An investigation using Spectroscopic Ellipsometery in Bio-Physical

    NASA Astrophysics Data System (ADS)

    Pfeiffer, Galen; Thompson, Daniel; Berberov, Emil; Woollam, John; Bleiweiss, Michael; Datta, Timir

    2001-03-01

    The present work is an investigation of bio-physical systems using spectroscopic ellipsometry (SE), with wavelengths ranging from deep-ultraviolet to the far infrared. Recent advances in SE hardware, software and data analysis permit rapid, non-contact investigation of physical properties of nano-dimensional soft-material films and interfaces such as bio-films under liquids. The kinetics of attachment, layer thickness, density of coverage, and identification of interfacial chemistry of proteins, for example, on surfaces is of practical and fundamental importance in biology and medicine, and are potentially measurable by SE. Our initial findings determine adsorption rates of Bovine Serum Albumin (BSA) and other bio-films on gold and polystyrene substrates, as well as their spatial distributions. We were also able to identify attachment of a 2.5 nm layer of the diarrhea causing E. coli enterotoxin (LT) to ganglioside (GM1) receptor, potentially simplifying and providing more information to standard enzyme linked immuno sorbent assay (ELISA) methods. Results of studies of several different bio-physical systems using SE will be discussed.

  14. The Standard Model of Nuclear Physics

    NASA Astrophysics Data System (ADS)

    Detmold, William

    2015-04-01

    At its core, nuclear physics, which describes the properties and interactions of hadrons, such as protons and neutrons, and atomic nuclei, arises from the Standard Model of particle physics. However, the complexities of nuclei result in severe computational difficulties that have historically prevented the calculation of central quantities in nuclear physics directly from this underlying theory. The availability of petascale (and prospect of exascale) high performance computing is changing this situation by enabling us to extend the numerical techniques of lattice Quantum Chromodynamics (LQCD), applied successfully in particle physics, to the more intricate dynamics of nuclear physics. In this talk, I will discuss this revolution and the emerging understanding of hadrons and nuclei within the Standard Model.

  15. Gas diffusion and physical property investigations for polar firn

    NASA Astrophysics Data System (ADS)

    Adolph, A. C.; Albert, M. R.

    2012-12-01

    Improved understanding of physical and gas transport properties of firn and their controls on interstitial gas diffusion would inform ice core interpretation and snow/atmosphere exchange processes. In particular, gas diffusivity is relevant in the important calculation of gas age/ice age differences, but extensive direct measurements of gas diffusivity of firn have not been made. This paper describes an investigation that relates gas diffusivity and permeability based on measurements of the physical properties of firn over a wide range of density. Gas diffusivity and permeability measurements were made on a set of homogeneous samples from varying depths between the surface and pore close-off at Summit, Greenland. Microstructural properties were obtained using Micro-CT measurements. Correlations between our findings and firn densification processes are examined.

  16. PHYSICAL MODELING OF CONTRACTED FLOW.

    USGS Publications Warehouse

    Lee, Jonathan K.

    1987-01-01

    Experiments on steady flow over uniform grass roughness through centered single-opening contractions were conducted in the Flood Plain Simulation Facility at the U. S. Geological Survey's Gulf Coast Hydroscience Center near Bay St. Louis, Miss. The experimental series was designed to provide data for calibrating and verifying two-dimensional, vertically averaged surface-water flow models used to simulate flow through openings in highway embankments across inundated flood plains. Water-surface elevations, point velocities, and vertical velocity profiles were obtained at selected locations for design discharges ranging from 50 to 210 cfs. Examples of observed water-surface elevations and velocity magnitudes at basin cross-sections are presented.

  17. Waste Feed Evaporation Physical Properties Modeling

    SciTech Connect

    Daniel, W.E.

    2003-08-25

    This document describes the waste feed evaporator modeling work done in the Waste Feed Evaporation and Physical Properties Modeling test specification and in support of the Hanford River Protection Project (RPP) Waste Treatment Plant (WTP) project. A private database (ZEOLITE) was developed and used in this work in order to include the behavior of aluminosilicates such a NAS-gel in the OLI/ESP simulations, in addition to the development of the mathematical models. Mathematical models were developed that describe certain physical properties in the Hanford RPP-WTP waste feed evaporator process (FEP). In particular, models were developed for the feed stream to the first ultra-filtration step characterizing its heat capacity, thermal conductivity, and viscosity, as well as the density of the evaporator contents. The scope of the task was expanded to include the volume reduction factor across the waste feed evaporator (total evaporator feed volume/evaporator bottoms volume). All the physical properties were modeled as functions of the waste feed composition, temperature, and the high level waste recycle volumetric flow rate relative to that of the waste feed. The goal for the mathematical models was to predict the physical property to predicted simulation value. The simulation model approximating the FEP process used to develop the correlations was relatively complex, and not possible to duplicate within the scope of the bench scale evaporation experiments. Therefore, simulants were made of 13 design points (a subset of the points used in the model fits) using the compositions of the ultra-filtration feed streams as predicted by the simulation model. The chemistry and physical properties of the supernate (the modeled stream) as predicted by the simulation were compared with the analytical results of experimental simulant work as a method of validating the simulation software.

  18. Physical Modelling of Sedimentary Basin

    SciTech Connect

    Yuen, David A.

    2003-04-24

    The main goals of the first three years have been achieved, i.e., the development of particle-based and continuum-based algorithms for cross-scaleup-scale analysis of complex fluid flows. The U. Minnesota team has focused on particle-based methods, wavelets (Rustad et al., 2001) and visualization and has had great success with the dissipative and fluid particle dynamics algorithms, as applied to colloidal, polymeric and biological systems, wavelet filtering and visualization endeavors. We have organized two sessions in nonlinear geophysics at the A.G.U. Fall Meeting (2000,2002), which have indeed synergetically stimulated the community and promoted cross-disciplinary efforts in the geosciences. The LANL team has succeeded with continuum-based algorithms, in particular, fractal interpolating functions (fif). These have been applied to 1-D flow and transport equations (Travis, 2000; 2002) as a proof of principle, providing solutions that capture dynamics at all scales. In addition, the fif representations can be integrated to provide sub-grid-scale homogenization, which can be used in more traditional finite difference or finite element solutions of porous flow and transport. Another useful tool for fluid flow problems is the ability to solve inverse problems, that is, given present-time observations of a fluid flow, what was the initial state of that fluid system? We have demonstrated this capability for a large-scale problem of 3-D flow in the Earth's crust (Bunge, Hagelberg & Travis, 2002). Use of the adjoint method for sensitivity analysis (Marchuk, 1995) to compute derivatives of models makes the large-scale inversion feasible in 4-D, , space and time. Further, a framework for simulating complex fluid flow in the Earth's crust has been implemented (Dutrow et al, 2001). The remaining task of the first three-year campaign is to extend the implementation of the fif formalism to our 2-D and 3-D computer codes, which is straightforward, but involved.

  19. Physical-statistical modeling in geophysics

    NASA Astrophysics Data System (ADS)

    Berliner, L. Mark

    2003-12-01

    Two powerful formulas have been available to scientists for more than two centuries: Newton's second law, providing a foundation for classical physics, and Bayes's theorem, prescribing probabilistic learning about unknown quantities based on observations. For the most part the use of these formulas has been separated, with Newton being the more dominant in geophysics. This separation is arguably surprising since numerous sources of uncertainty arise in the application of classical physics in complex situations. One explanation for the separation is the difficulty in implementing Bayesian analysis in complex settings. However, recent advances in both modeling strategies and computational tools have contributed to a significant change in the scope and feasibility of Bayesian analysis. This paradigm provides opportunities for the combination of physical reasoning and observational data in a coherent analysis framework but in a fashion which manages the uncertainties in both information sources. A key to the modeling is the hierarchical viewpoint, in which separate statistical models are developed for the process variables studied and for the observations conditional on those variables. Modeling process variables in this way enables the incorporation of physics across a spectrum of levels of intensity, ranging from a qualitative use of physical reasoning to a strong reliance on numerical models. Selected examples from this spectrum are reviewed. So far as the laws of mathematics refer to reality, they are not certain. And so far as they are certain, they do not refer to reality.Albert Einstein (1921)

  20. Investigating elementary education and physical therapy majors' perceptions of an inquiry-based physics content course

    NASA Astrophysics Data System (ADS)

    Hilton, John Martin

    This study investigates why physical therapy assistant majors engage and perform better than elementary education majors in an inquiry-based conceptual physics course at Mid-Atlantic Community College. The students from each major are demographically similar, both courses are similar in depth and structure, and each course supports the students' program. However, there is an observed difference in the levels of engagement with the curriculum and performance on writing-based assessments between the two groups. To explore possible explanations for the difference, I examine students' affinity for science, their beliefs about the nature of science and scientific knowledge in the classroom, and their perception of the usefulness of science to their program. During semi-structured interviews, students from both majors displayed nearly identical weak affinities for science, epistemological beliefs, and uncertainty about the usefulness of the class. However, the physical therapy majors' ability to see the relevance of the physics course experience to their program enhanced their interest and motivation. In contrast, the elementary education students do not see connections between the course and their program, and do not see a purpose for their learning of physics content. To improve the program, I propose a two-pronged approach - designing a faded-scaffolded-inquiry approach for both classes, and developing a field-based/seminar class for the elementary education majors. The scaffolded inquiry will help both groups develop better orientations toward lab activities, and the structured observations and reflection will help the elementary group connect the material to their program.

  1. [Investigations in dynamics of gauge theories in theoretical particle physics

    SciTech Connect

    Not Available

    1993-02-01

    The major theme of the theoretical physics research conducted under DOE support over the past several years has been within the rubric of the standard model, and concerned the interplay between symmetries and dynamics. The research was thus carried out mostly in the context of gauge field theories, and usually in the presence of chiral fermions. Dynamical symmetry breaking was examined both from the point of view of perturbation theory, as well as from non-perturbative techniques associated with certain characteristic features of specific theories. Among the topics of research were: the implications of abelian and non-abelian anomalies on the spectrum and possible dynamical symmetry breaking in any theory, topological and conformal properties of quantum fields in two and higher dimensions, the breaking of global chiral symmetries by vector-like gauge theories such as QCD, the phenomenological implications of a strongly interacting Higgs sector in the standard model, and the application of soliton ideas to the physics to be explored at the SSC.

  2. LETTER: Statistical physics of the Schelling model of segregation

    NASA Astrophysics Data System (ADS)

    Dall'Asta, L.; Castellano, C.; Marsili, M.

    2008-07-01

    We investigate the static and dynamic properties of a celebrated model of social segregation, providing a complete explanation of the mechanisms leading to segregation both in one- and two-dimensional systems. Standard statistical physics methods shed light on the rich phenomenology of this simple model, exhibiting static phase transitions typical of kinetic constrained models, non-trivial coarsening like in driven-particle systems and percolation-related phenomena.

  3. Simplified models for LHC new physics searches

    NASA Astrophysics Data System (ADS)

    Alves, Daniele; Arkani-Hamed, Nima; Arora, Sanjay; Bai, Yang; Baumgart, Matthew; Berger, Joshua; Buckley, Matthew; Butler, Bart; Chang, Spencer; Cheng, Hsin-Chia; Cheung, Clifford; Sekhar Chivukula, R.; Cho, Won Sang; Cotta, Randy; D'Alfonso, Mariarosaria; El Hedri, Sonia; Essig (Editor, Rouven; Evans, Jared A.; Fitzpatrick, Liam; Fox, Patrick; Franceschini, Roberto; Freitas, Ayres; Gainer, James S.; Gershtein, Yuri; Gray, Richard; Gregoire, Thomas; Gripaios, Ben; Gunion, Jack; Han, Tao; Haas, Andy; Hansson, Per; Hewett, JoAnne; Hits, Dmitry; Hubisz, Jay; Izaguirre, Eder; Kaplan, Jared; Katz, Emanuel; Kilic, Can; Kim, Hyung-Do; Kitano, Ryuichiro; Koay, Sue Ann; Ko, Pyungwon; Krohn, David; Kuflik, Eric; Lewis, Ian; Lisanti (Editor, Mariangela; Liu, Tao; Liu, Zhen; Lu, Ran; Luty, Markus; Meade, Patrick; Morrissey, David; Mrenna, Stephen; Nojiri, Mihoko; Okui, Takemichi; Padhi, Sanjay; Papucci, Michele; Park, Michael; Park, Myeonghun; Perelstein, Maxim; Peskin, Michael; Phalen, Daniel; Rehermann, Keith; Rentala, Vikram; Roy, Tuhin; Ruderman, Joshua T.; Sanz, Veronica; Schmaltz, Martin; Schnetzer, Stephen; Schuster (Editor, Philip; Schwaller, Pedro; Schwartz, Matthew D.; Schwartzman, Ariel; Shao, Jing; Shelton, Jessie; Shih, David; Shu, Jing; Silverstein, Daniel; Simmons, Elizabeth; Somalwar, Sunil; Spannowsky, Michael; Spethmann, Christian; Strassler, Matthew; Su, Shufang; Tait (Editor, Tim; Thomas, Brooks; Thomas, Scott; Toro (Editor, Natalia; Volansky, Tomer; Wacker (Editor, Jay; Waltenberger, Wolfgang; Yavin, Itay; Yu, Felix; Zhao, Yue; Zurek, Kathryn; LHC New Physics Working Group

    2012-10-01

    This document proposes a collection of simplified models relevant to the design of new-physics searches at the Large Hadron Collider (LHC) and the characterization of their results. Both ATLAS and CMS have already presented some results in terms of simplified models, and we encourage them to continue and expand this effort, which supplements both signature-based results and benchmark model interpretations. A simplified model is defined by an effective Lagrangian describing the interactions of a small number of new particles. Simplified models can equally well be described by a small number of masses and cross-sections. These parameters are directly related to collider physics observables, making simplified models a particularly effective framework for evaluating searches and a useful starting point for characterizing positive signals of new physics. This document serves as an official summary of the results from the ‘Topologies for Early LHC Searches’ workshop, held at SLAC in September of 2010, the purpose of which was to develop a set of representative models that can be used to cover all relevant phase space in experimental searches. Particular emphasis is placed on searches relevant for the first ˜50-500 pb-1 of data and those motivated by supersymmetric models. This note largely summarizes material posted at http://lhcnewphysics.org/, which includes simplified model definitions, Monte Carlo material, and supporting contacts within the theory community. We also comment on future developments that may be useful as more data is gathered and analyzed by the experiments.

  4. Simplified Models for LHC New Physics Searches

    SciTech Connect

    Alves, Daniele; Arkani-Hamed, Nima; Arora, Sanjay; Bai, Yang; Baumgart, Matthew; Berger, Joshua; Buckley, Matthew; Butler, Bart; Chang, Spencer; Cheng, Hsin-Chia; Cheung, Clifford; Chivukula, R.Sekhar; Cho, Won Sang; Cotta, Randy; D'Alfonso, Mariarosaria; El Hedri, Sonia; Essig, Rouven,; Evans, Jared A.; Fitzpatrick, Liam; Fox, Patrick; Franceschini, Roberto; /more authors..

    2012-06-01

    This document proposes a collection of simplified models relevant to the design of new-physics searches at the LHC and the characterization of their results. Both ATLAS and CMS have already presented some results in terms of simplified models, and we encourage them to continue and expand this effort, which supplements both signature-based results and benchmark model interpretations. A simplified model is defined by an effective Lagrangian describing the interactions of a small number of new particles. Simplified models can equally well be described by a small number of masses and cross-sections. These parameters are directly related to collider physics observables, making simplified models a particularly effective framework for evaluating searches and a useful starting point for characterizing positive signals of new physics. This document serves as an official summary of the results from the 'Topologies for Early LHC Searches' workshop, held at SLAC in September of 2010, the purpose of which was to develop a set of representative models that can be used to cover all relevant phase space in experimental searches. Particular emphasis is placed on searches relevant for the first {approx} 50-500 pb{sup -1} of data and those motivated by supersymmetric models. This note largely summarizes material posted at http://lhcnewphysics.org/, which includes simplified model definitions, Monte Carlo material, and supporting contacts within the theory community. We also comment on future developments that may be useful as more data is gathered and analyzed by the experiments.

  5. A physical corrosion model for bioabsorbable metal stents.

    PubMed

    Grogan, J A; Leen, S B; McHugh, P E

    2014-05-01

    Absorbable metal stents (AMSs) are an emerging technology in the treatment of heart disease. Computational modelling of AMS performance will facilitate the development of this technology. In this study a physical corrosion model is developed for AMSs based on the finite element method and adaptive meshing. The model addresses a gap between currently available phenomenological corrosion models for AMSs and physical corrosion models that have been developed for more simple geometries than those of a stent. The model developed in this study captures the changing surface of a corroding three-dimensional AMS structure for the case of diffusion-controlled corrosion. Comparisons are made between model predictions and those of previously developed phenomenological corrosion models for AMSs in terms of predicted device geometry and mechanical performance during corrosion. Relationships between alloy solubility and diffusivity in the corrosion environment and device performance during corrosion are also investigated.

  6. Comparisons between physical model and numerical model results

    SciTech Connect

    Sagasta, P.F.

    1986-04-01

    Physical modeling scaling laws provide the opportunity to compare results among numerical modeling programs, including two- and three-dimensional interactive-raytracing and more sophisticated wave-equation-approximation methods, and seismic data collected over a known, three-dimensional model in a water tank. The sixfold closely spaced common-midpoint water-tank data modeled for this study simulate a standard marine three-dimensional survey shot over a three-layered physical model (a structured upper layer overlying two flat layers. Using modeling theory, the physical-tank model dimensions scale to realistic exploration dimensions, and the ultrasonic frequencies scale to seismic frequencies of 2-60 Hz. A comparison of P and converted-S events and amplitudes among these physical tank data and numerical modeling results illustrates many of the advantages and limitations of modeling methods available to the exploration geophysicist. The ability of three-dimensional raytracing to model off-line events and more closely predict waveform phase due to geometric effects shows the greater usefulness of three-dimensional modeling methods over two-dimensional methods in seismic interpretation. Forward modeling of P to Sv-converted events and multiples predicts their presence in the seismic data. The geometry of the physical model leads to examples where raytracing approximations are limited and the more time-consuming finite-element technique is useful to better understand wave propagation within the physical model. All of the numerical modeling programs used show limitations in matching the amplitudes and phase of events in the physical-model seismic data.

  7. Physical and stochastic models of earthquake clustering

    NASA Astrophysics Data System (ADS)

    Console, Rodolfo; Murru, Maura; Catalli, Flaminia

    2006-04-01

    The phenomenon of earthquake clustering, i.e., the increase of occurrence probability for seismic events close in space and time to other previous earthquakes, has been modeled both by statistical and physical processes. From a statistical viewpoint the so-called epidemic model (ETAS) introduced by Ogata in 1988 and its variations have become fairly well known in the seismological community. Tests on real seismicity and comparison with a plain time-independent Poissonian model through likelihood-based methods have reliably proved their validity. On the other hand, in the last decade many papers have been published on the so-called Coulomb stress change principle, based on the theory of elasticity, showing qualitatively that an increase of the Coulomb stress in a given area is usually associated with an increase of seismic activity. More specifically, the rate-and-state theory developed by Dieterich in the '90s has been able to give a physical justification to the phenomenon known as Omori law. According to this law, a mainshock is followed by a series of aftershocks whose frequency decreases in time as an inverse power law. In this study we give an outline of the above-mentioned stochastic and physical models, and build up an approach by which these models can be merged in a single algorithm and statistically tested. The application to the seismicity of Japan from 1970 to 2003 shows that the new model incorporating the physical concept of the rate-and-state theory performs not worse than the purely stochastic model with two free parameters only. The numerical results obtained in these applications are related to physical characters of the model as the stress change produced by an earthquake close to its edges and to the A and σ parameters of the rate-and-state constitutive law.

  8. A physical analogue of the Schelling model

    NASA Astrophysics Data System (ADS)

    Vinković, Dejan; Kirman, Alan

    2006-12-01

    We present a mathematical link between Schelling's socio-economic model of segregation and the physics of clustering. We replace the economic concept of "utility" by the physics concept of a particle's internal energy. As a result cluster dynamics is driven by the "surface tension" force. The resultant segregated areas can be very large and can behave like spherical "liquid" droplets or as a collection of static clusters in "frozen" form. This model will hopefully provide a useful framework for studying many spatial economic phenomena that involve individuals making location choices as a function of the characteristics and choices of their neighbors.

  9. Physical methods for investigating structural colours in biological systems

    PubMed Central

    Vukusic, P.; Stavenga, D.G.

    2009-01-01

    Many biological systems are known to use structural colour effects to generate aspects of their appearance and visibility. The study of these phenomena has informed an eclectic group of fields ranging, for example, from evolutionary processes in behavioural biology to micro-optical devices in technologically engineered systems. However, biological photonic systems are invariably structurally and often compositionally more elaborate than most synthetically fabricated photonic systems. For this reason, an appropriate gamut of physical methods and investigative techniques must be applied correctly so that the systems' photonic behaviour may be appropriately understood. Here, we survey a broad range of the most commonly implemented, successfully used and recently innovated physical methods. We discuss the costs and benefits of various spectrometric methods and instruments, namely scatterometers, microspectrophotometers, fibre-optic-connected photodiode array spectrometers and integrating spheres. We then discuss the role of the materials' refractive index and several of the more commonly used theoretical approaches. Finally, we describe the recent developments in the research field of photonic crystals and the implications for the further study of structural coloration in animals. PMID:19158009

  10. Plasma simulation studies using multilevel physics models

    SciTech Connect

    Park, W.; Belova, E.V.; Fu, G.Y.

    2000-01-19

    The question of how to proceed toward ever more realistic plasma simulation studies using ever increasing computing power is addressed. The answer presented here is the M3D (Multilevel 3D) project, which has developed a code package with a hierarchy of physics levels that resolve increasingly complete subsets of phase-spaces and are thus increasingly more realistic. The rationale for the multilevel physics models is given. Each physics level is described and examples of its application are given. The existing physics levels are fluid models (3D configuration space), namely magnetohydrodynamic (MHD) and two-fluids; and hybrid models, namely gyrokinetic-energetic-particle/MHD (5D energetic particle phase-space), gyrokinetic-particle-ion/fluid-electron (5D ion phase-space), and full-kinetic-particle-ion/fluid-electron level (6D ion phase-space). Resolving electron phase-space (5D or 6D) remains a future project. Phase-space-fluid models are not used in favor of delta f particle models. A practical and accurate nonlinear fluid closure for noncollisional plasmas seems not likely in the near future.

  11. Dilution physics modeling: Dissolution/precipitation chemistry

    SciTech Connect

    Onishi, Y.; Reid, H.C.; Trent, D.S.

    1995-09-01

    This report documents progress made to date on integrating dilution/precipitation chemistry and new physical models into the TEMPEST thermal-hydraulics computer code. Implementation of dissolution/precipitation chemistry models is necessary for predicting nonhomogeneous, time-dependent, physical/chemical behavior of tank wastes with and without a variety of possible engineered remediation and mitigation activities. Such behavior includes chemical reactions, gas retention, solids resuspension, solids dissolution and generation, solids settling/rising, and convective motion of physical and chemical species. Thus this model development is important from the standpoint of predicting the consequences of various engineered activities, such as mitigation by dilution, retrieval, or pretreatment, that can affect safe operations. The integration of a dissolution/precipitation chemistry module allows the various phase species concentrations to enter into the physical calculations that affect the TEMPEST hydrodynamic flow calculations. The yield strength model of non-Newtonian sludge correlates yield to a power function of solids concentration. Likewise, shear stress is concentration-dependent, and the dissolution/precipitation chemistry calculations develop the species concentration evolution that produces fluid flow resistance changes. Dilution of waste with pure water, molar concentrations of sodium hydroxide, and other chemical streams can be analyzed for the reactive species changes and hydrodynamic flow characteristics.

  12. Service Learning In Physics: The Consultant Model

    NASA Astrophysics Data System (ADS)

    Guerra, David

    2005-04-01

    Each year thousands of students across the country and across the academic disciplines participate in service learning. Unfortunately, with no clear model for integrating community service into the physics curriculum, there are very few physics students engaged in service learning. To overcome this shortfall, a consultant based service-learning program has been developed and successfully implemented at Saint Anselm College (SAC). As consultants, students in upper level physics courses apply their problem solving skills in the service of others. Most recently, SAC students provided technical and managerial support to a group from Girl's Inc., a national empowerment program for girls in high-risk, underserved areas, who were participating in the national FIRST Lego League Robotics competition. In their role as consultants the SAC students provided technical information through brainstorming sessions and helped the girls stay on task with project management techniques, like milestone charting. This consultant model of service-learning, provides technical support to groups that may not have a great deal of resources and gives physics students a way to improve their interpersonal skills, test their technical expertise, and better define the marketable skill set they are developing through the physics curriculum.

  13. Transforming teacher knowledge: Modeling instruction in physics

    NASA Astrophysics Data System (ADS)

    Cabot, Lloyd H.

    I show that the Modeling physics curriculum is readily accommodated by most teachers in favor of traditional didactic pedagogies. This is so, at least in part, because Modeling focuses on a small set of connected models embedded in a self-consistent theoretical framework and thus is closely congruent with human cognition in this context which is to generate mental models of physical phenomena as both predictive and explanatory devices. Whether a teacher fully implements the Modeling pedagogy depends on the depth of the teacher's commitment to inquiry-based instruction, specifically Modeling instruction, as a means of promoting student understanding of Newtonian mechanics. Moreover, this commitment trumps all other characteristics: teacher educational background, content coverage issues, student achievement data, district or state learning standards, and district or state student assessments. Indeed, distinctive differences exist in how Modeling teachers deliver their curricula and some teachers are measurably more effective than others in their delivery, but they all share an unshakable belief in the efficacy of inquiry-based, constructivist-oriented instruction. The Modeling Workshops' pedagogy, duration, and social interactions impacts teachers' self-identification as members of a professional community. Finally, I discuss the consequences my research may have for the Modeling Instruction program designers and for designers of professional development programs generally.

  14. Full-waveform modeling and inversion of physical model data

    NASA Astrophysics Data System (ADS)

    Cai, Jian; Zhang, Jie

    2016-08-01

    Because full elastic waveform inversion requires considerable computation time for forward modeling and inversion, acoustic waveform inversion is often applied to marine data for reducing the computational time. To understand the validity of the acoustic approximation, we study data collected from an ultrasonic laboratory with a known physical model by applying elastic and acoustic waveform modeling and acoustic waveform inversion. This study enables us to evaluate waveform differences quantitatively between synthetics and real data from the same physical model and to understand the effects of different objective functions in addressing the waveform differences for full-waveform inversion. Because the materials used in the physical experiment are viscoelastic, we find that both elastic and acoustic synthetics differ substantially from the physical data over offset in true amplitude. If attenuation is taken into consideration, the amplitude versus offset (AVO) of viscoelastic synthetics more closely approximates the physical data. To mitigate the effect of amplitude differences, we apply trace normalization to both synthetics and physical data in acoustic full-waveform inversion. The objective function is equivalent to minimizing the phase differences with indirect contributions from the amplitudes. We observe that trace normalization helps to stabilize the inversion and obtain more accurate model solutions for both synthetics and physical data.

  15. Modelling Students' Construction of Energy Models in Physics.

    ERIC Educational Resources Information Center

    Devi, Roshni; And Others

    1996-01-01

    Examines students' construction of experimentation models for physics theories in energy storage, transformation, and transfers involving electricity and mechanics. Student problem solving dialogs and artificial intelligence modeling of these processes is analyzed. Construction of models established relations between elements with linear causal…

  16. Advantages of High Resolution Modeling to Investigate Urbanization Impacts

    NASA Astrophysics Data System (ADS)

    Kirsch, B.; Lopez, S. R.; Condon, L. E.; Maxwell, R. M.

    2012-12-01

    Urban infrastructures have impervious surfaces that directly affect the hydrology of the system. Impervious surfaces affect drainage networks, alter aqueous flow paths, change feedbacks to the atmosphere and promote contaminant transport. Through the usage of a fully integrated physical hydrology model, this study aims to investigate the impacts of green infrastructure within an urban environment. The model used for analysis is ParFlow, a fully coupled physical hydrologic model that simulates surface and subsurface water interactions, coupled with the common land model (CLM) to simulate land surface processes. Analysis includes investigating stormwater routing, infiltration, pollutant transport and water quality during infiltration and storage on a test domain. This work will also investigate, from an economic perspective, the costs of urbanization upon water resources and under what conditions green infrastructure projects may produce positive benefit-cost ratios, as well as how such infrastructure may impact optimal water resource management strategies.

  17. Physics Beyond the Standard Model: Supersymmetry

    SciTech Connect

    Nojiri, M.M.; Plehn, T.; Polesello, G.; Alexander, John M.; Allanach, B.C.; Barr, Alan J.; Benakli, K.; Boudjema, F.; Freitas, A.; Gwenlan, C.; Jager, S.; /CERN /LPSC, Grenoble

    2008-02-01

    This collection of studies on new physics at the LHC constitutes the report of the supersymmetry working group at the Workshop 'Physics at TeV Colliders', Les Houches, France, 2007. They cover the wide spectrum of phenomenology in the LHC era, from alternative models and signatures to the extraction of relevant observables, the study of the MSSM parameter space and finally to the interplay of LHC observations with additional data expected on a similar time scale. The special feature of this collection is that while not each of the studies is explicitly performed together by theoretical and experimental LHC physicists, all of them were inspired by and discussed in this particular environment.

  18. Investigating Attitudes toward Physical Education: Validation across Two Instruments

    ERIC Educational Resources Information Center

    Donovan, Corinne Baron; Mercier, Kevin; Phillips, Sharon R.

    2015-01-01

    The Centers for Disease Control have suggested that physical education plays a role in promoting healthy lifestyles. Prior research suggests a link between attitudes toward physical education and physical activity outside school. The current study provides additional evidence of construct validity through a validation across two instruments…

  19. Physics of Granular Materials: Investigations in Support of Astrobiology

    NASA Technical Reports Server (NTRS)

    Marshall, John R.

    2002-01-01

    This publication list is submitted as a summary of the work conducted under Cooperative Agreement 1120. The goal of the 1120 research was to study granular materials within a planetary, astrophysical, and astrobiological context. This involved research on the physical, mechanical and electrostatic properties of granular systems, as well as the examination of these materials with atomic force microscopy and x-ray analysis. Instruments for analyzing said materials in planetary environments were developed, including the MECA (Mars Environment Compatibility Assessment) experiment for the MSP '01 lander, the ECHOS/MATADOR experiment for the MSP '03 lander, an ISRU experiment for the '03 lander, and MiniLEAP technology. Flight experiments for microgravity (Space Station and Shuttle) have also been developed for the study of granular materials. As expressed in the publications, work on 1120 encompassed laboratory research, theoretical modeling, field experiments, and flight experiments: a series of successful new models were developed for understanding the behavior of triboelectrostatically charged granular masses, and 4 separate instruments were selected for space flight. No inventions or patents were generated by the research under this Agreement.

  20. Prototyping of cerebral vasculature physical models

    PubMed Central

    Khan, Imad S.; Kelly, Patrick D.; Singer, Robert J.

    2014-01-01

    Background: Prototyping of cerebral vasculature models through stereolithographic methods have the ability to accurately depict the 3D structures of complicated aneurysms with high accuracy. We describe the method to manufacture such a model and review some of its uses in the context of treatment planning, research, and surgical training. Methods: We prospectively used the data from the rotational angiography of a 40-year-old female who presented with an unruptured right paraclinoid aneurysm. The 3D virtual model was then converted to a physical life-sized model. Results: The model constructed was shown to be a very accurate depiction of the aneurysm and its associated vasculature. It was found to be useful, among other things, for surgical training and as a patient education tool. Conclusion: With improving and more widespread printing options, these models have the potential to become an important part of research and training modalities. PMID:24678427

  1. Physical Modeling of the Composting Ecosystem †

    PubMed Central

    Hogan, J. A.; Miller, F. C.; Finstein, M. S.

    1989-01-01

    A composting physical model with an experimental chamber with a working volume of 14 × 103 cm3 (0.5 ft3) was designed to avoid exaggerated conductive heat loss resulting from, relative to field-scale piles, a disproportionately large outer surface-area-to-volume ratio. In the physical model, conductive flux (rate of heat flow through chamber surfaces) was made constant and slight through a combination of insulation and temperature control of the surrounding air. This control was based on the instantaneous conductive flux, as calculated from temperature differentials via a conductive heat flow model. An experiment was performed over a 10-day period in which control of the composting process was based on ventilative heat removal in reference to a microbially favorable temperature ceiling (temperature feedback). By using the conduction control system (surrounding air temperature controlled), 2.4% of the total heat evolved from the chamber was through conduction, whereas the remainder was through the ventilative mechanisms of the latent heat of vaporization and the sensible temperature increase of air. By comparison, with insulation alone (the conduction control system was not used) conduction accounted for 33.5% of the total heat evolved. This difference in conduction resulted in substantial behavioral differences with respect to the temperature of the composting matrix and the amount of water removed. By emphasizing the slight conduction system (2.4% of total heat flow) as being a better representative of field conditions, a comparison was made between composting system behavior in the laboratory physical model and field-scale piles described in earlier reports. Numerous behavioral patterns were qualitatively similar in the laboratory and field (e.g., temperature gradient, O2 content, and water removal). It was concluded that field-scale composting system behavior can be simulated reasonably faithfully in the physical model. Images PMID:16347903

  2. Dissolution of magnetically marked tablets: investigations in a physical phantom.

    PubMed

    Biller, S; Domey, J; Fiedler, P; Holzhey, R; Richert, H; Haueisen, J

    2012-01-01

    Pharmacological research is strongly driven by maximizing the bioavailability of new pharmaceuticals. For orally applied drugs the bioavailability highly depends on the process of dissolution in the gastrointestinal tract and is affected by numerous physiological and environmental factors. Available techniques for in vivo monitoring of the dissolution process are very limited and not applicable for large studies. The technique of magnetic marker monitoring provides new prospects for these investigations. However, it is currently limited due to low fields common magnetic markers produce. Hence, only highly sensitive sensors are applicable. In this paper, we performed dissolution tests of novel markers in a physical phantom with magnetoresistive sensors in an unshielded environment. The markers were continuously localized and the movement through the phantom was tracked. By analyzing the changing magnetic moment of the markers we were able to monitor the progress of dissolution in the phantom. We conclude that our proposed phantom and tracking technique is an important step towards new systems for in vivo monitoring of pharmaceutical dissolution processes. PMID:23366328

  3. Investigating Transitions in Planetary Dynamo Models

    NASA Astrophysics Data System (ADS)

    Soderlund, Krista Marie

    All planets in the solar system have or once had intrinsic magnetic fields, with the possible exception of Venus. The properties and characteristics of these fields are as diverse as the planets themselves. Given this diversity, the fundamental goal is to determine what controls the strength, morphology, and evolution of planetary magnetic fields. Since these fields are thought to result from dynamo action driven by thermochemical convection in electrically-conducting fluid regions, the coupling between magnetic fields, fluid flow, and heat/mass transfer must also be understood. We seek to investigate this coupling and to understand better the processes that occur in numerical dynamo models and, hopefully, in planetary cores as well. I have carried out a suite of dynamo and non-magnetic, but otherwise identical, models which are compared in order to quantify the influence of magnetic fields on convective dynamics systematically and to understand why the Lorentz force has a surprisingly weak dynamical role in magnetic systems. The characteristics of convection, including convective flow structures and speeds as well as heat transfer, are found to be only weakly affected by the presence of magnetic fields. We compare different parameterizations of the relative influence of magnetic and rotational forces and show that the traditional Elsasser number overestimates the role of the Lorentz force in dynamos. Instead, we argue that an alternatively defined 'dynamic Elsasser number' better represents the Lorentz to Coriolis force ratio. We also find a sharp transition between dipolar and multipolar dynamos. This morphological transition is linked to the breakdown of helical flow as inertial forces become stronger than viscous forces. Because viscous forces are negligible in planetary interiors, my findings imply that present day dynamo models with moderate rotation rates ( E ≳ 10-4) may be too viscous to reproduce the physical mechanisms of field generation in planetary

  4. Quantitative investigation of ligament strains during physical tests for sacroiliac joint pain using finite element analysis.

    PubMed

    Kim, Yoon Hyuk; Yao, Zhidong; Kim, Kyungsoo; Park, Won Man

    2014-06-01

    It may be assumed that the stability is affected when some ligaments are injured or loosened, and this joint instability causes sacroiliac joint pain. Several physical examinations have been used to diagnose sacroiliac pain and to isolate the source of the pain. However, more quantitative and objective information may be necessary to identify unstable or injured ligaments during these tests due to the lack of understanding of the quantitative relationship between the physical tests and the biomechanical parameters that may be related to pains in the sacroiliac joint and the surrounding ligaments. In this study, a three-dimensional finite element model of the sacroiliac joint was developed and the biomechanical conditions for six typical physical tests such as the compression test, distraction test, sacral apex pressure test, thigh thrust test, Patrick's test, and Gaenslen's test were modelled. The sacroiliac joint contact pressure and ligament strain were investigated for each test. The values of contact pressure and the combination of most highly strained ligaments differed markedly among the tests. Therefore, these findings in combination with the physical tests would be helpful to identify the pain source and to understand the pain mechanism. Moreover, the technology provided in this study might be a useful tool to evaluate the physical tests, to improve the present test protocols, or to develop a new physical test protocol.

  5. Introduction. Stochastic physics and climate modelling.

    PubMed

    Palmer, T N; Williams, P D

    2008-07-28

    Finite computing resources limit the spatial resolution of state-of-the-art global climate simulations to hundreds of kilometres. In neither the atmosphere nor the ocean are small-scale processes such as convection, clouds and ocean eddies properly represented. Climate simulations are known to depend, sometimes quite strongly, on the resulting bulk-formula representation of unresolved processes. Stochastic physics schemes within weather and climate models have the potential to represent the dynamical effects of unresolved scales in ways which conventional bulk-formula representations are incapable of so doing. The application of stochastic physics to climate modelling is a rapidly advancing, important and innovative topic. The latest research findings are gathered together in the Theme Issue for which this paper serves as the introduction.

  6. Some Generalized Physical Models Through Homographic Group

    NASA Astrophysics Data System (ADS)

    Agop, Maricel; Gavriluţ, Alina

    2015-10-01

    In the present paper some generalized physical models are established using differential and integral elements geometry of the homographic group. The generalization of the hyperbolic motions (with constant acceleration) on the Minkowskian space-time and classical Kepler problems is analyzed using a variational principle of Matzner-Misner type. This way the Skyrme theory is placed in an inherent continuity with respect to the Newtonian natural philosophy.

  7. Physical modelling of failure in composites.

    PubMed

    Talreja, Ramesh

    2016-07-13

    Structural integrity of composite materials is governed by failure mechanisms that initiate at the scale of the microstructure. The local stress fields evolve with the progression of the failure mechanisms. Within the full span from initiation to criticality of the failure mechanisms, the governing length scales in a fibre-reinforced composite change from the fibre size to the characteristic fibre-architecture sizes, and eventually to a structural size, depending on the composite configuration and structural geometry as well as the imposed loading environment. Thus, a physical modelling of failure in composites must necessarily be of multi-scale nature, although not always with the same hierarchy for each failure mode. With this background, the paper examines the currently available main composite failure theories to assess their ability to capture the essential features of failure. A case is made for an alternative in the form of physical modelling and its skeleton is constructed based on physical observations and systematic analysis of the basic failure modes and associated stress fields and energy balances. This article is part of the themed issue 'Multiscale modelling of the structural integrity of composite materials'. PMID:27242307

  8. Physical models of polarization mode dispersion

    SciTech Connect

    Menyuk, C.R.; Wai, P.K.A.

    1995-12-31

    The effect of randomly varying birefringence on light propagation in optical fibers is studied theoretically in the parameter regime that will be used for long-distance communications. In this regime, the birefringence is large and varies very rapidly in comparison to the nonlinear and dispersive scale lengths. We determine the polarization mode dispersion, and we show that physically realistic models yield the same result for polarization mode dispersion as earlier heuristic models that were introduced by Poole. We also prove an ergodic theorem.

  9. Investigating and Accounting for Physics Graduate Students' Tutorial Classroom Practice

    ERIC Educational Resources Information Center

    Goertzen, Renee Michelle

    2010-01-01

    Physics Education researchers have been working to understanding how students learn physics, which has led to the creation of a body of research-based curricula. It is equally important to study novice instructors, graduate teaching assistants (TAs), who often teach these students. The study of TAs has similarities to how students have been…

  10. Physics Instruction in Secondary Schools: An Investigation of Teachers' Beliefs towards Physics Laboratory and ICT

    ERIC Educational Resources Information Center

    Siorenta, Anastassia; Jimoyiannis, Athanassios

    2008-01-01

    This paper reports on the examination of physics teachers' beliefs and perceptions of laboratory and ICT supported physics instruction. The findings indicate that the teachers in the sample were generally positive about the affordances offered by the physics lab and ICT in physics instruction. However, school culture context, mainly the need to…

  11. A Comprehensive Investigation Into Modeling Supernovae Spectra

    NASA Astrophysics Data System (ADS)

    Hillier, Desmond

    Supernovae are a rich source of information. By studying their light curves and spectra we gain insights into stellar evolution, the nature of the progenitor star, surface abundances at the time of the explosion, whether previous mass-loss episodes have occurred, the physics of the explosion including the amount and type of elements synthesized, and whether the explosion has produced significant mixing between shells of different chemical composition. To maximize the information that can be gleaned from observations of supernovae it is essential that we have the necessary spectroscopic tools. To this end, we are developing a code, CMFGEN, capable of modeling supernova light curves and spectra. The code is currently being used, to study core-collapse supernovae as well as those arising from the nuclear detonation of a White Dwarf star. We wish to extend CMFGEN's capabilities by developing a procedure to handle non-monotonic velocity flows so that we can treat shock breakout and the interaction of supernova ejecta with circumstellar material. We will also investigate magnetar-powered SNe, and explore the connection between Type Ib and Type Ic supernovae and those supernovae associated with long-duration gamma-ray bursters. Through detailed studies of individual supernova, and through the construction of model grids, we are able to infer deficiencies in our modeling, in our atomic data, and in the progenitor models, and hence make refinements so that we can improve our understanding of all SNe classes. Previous (IUE), current (HST, Chandra, GALEX), and future NASA missions (James Webb Telescope) do/will provide a wealth of data on supernovae. The proposed research is related to strategic subgoal 3D: "Discover the origin, structure, evolution, and destiny of the universe, and search for Earth-like planets." Supernovae are inherently coupled to the evolution of the universe and life: They can trigger star formation and they provide the raw materials (e.g., oxygen

  12. Investigation of the Physics of Flocculation in Algal Systems

    NASA Astrophysics Data System (ADS)

    Pierce, Flint; Lechman, Jeremy; Hewson, John

    2012-02-01

    Algae biofuel production has gained a great deal of interest in recent years due to the high photosynthetic efficiency of various algae strains and the ability of stressed algae populations to produce large quantities of lipids within their cells. Separation of the algae from the background aqueous medium engenders large energetic costs for standard separation techniques including filtration, centrifugation, and dissolved air flotation since algae cells are small (microns to 10s of microns), have densities similar to the surrounding fluid, and normally occur at low volume fractions (1E-4 -> 1E-3). Flocculation is one possible route to reducing the cost of collecting the algae biomass, since large algae flocs can easily be removed from the aqueous environment through either differential settling or standard filtration. To this end, We model flocculating systems of algae cells using discrete particle dynamics techniques which incorporate a recently developed adhesive granular potential to govern the cell interactions. This potential is shown to reproduce morphological characteristics, kinetics, and size distributions that agree well with known results for flocculation in the diffusive regime (DLCA). We further investigate flocculation under steady shear and compare our results to both experiment and predictions from various orthokinetic models.

  13. Physical vs. Mathematical Models in Rock Mechanics

    NASA Astrophysics Data System (ADS)

    Morozov, I. B.; Deng, W.

    2013-12-01

    One of the less noted challenges in understanding the mechanical behavior of rocks at both in situ and lab conditions is the character of theoretical approaches being used. Currently, the emphasis is made on spatial averaging theories (homogenization and numerical models of microstructure), empirical models for temporal behavior (material memory, compliance functions and complex moduli), and mathematical transforms (Laplace and Fourier) used to infer the Q-factors and 'relaxation mechanisms'. In geophysical applications, we have to rely on such approaches for very broad spatial and temporal scales which are not available in experiments. However, the above models often make insufficient use of physics and utilize, for example, the simplified 'correspondence principle' instead of the laws of viscosity and friction. As a result, the commonly-used time- and frequency dependent (visco)elastic moduli represent apparent properties related to the measurement procedures and not necessarily to material properties. Predictions made from such models may therefore be inaccurate or incorrect when extrapolated beyond the lab scales. To overcome the above challenge, we need to utilize the methods of micro- and macroscopic mechanics and thermodynamics known in theoretical physics. This description is rigorous and accurate, uses only partial differential equations, and allows straightforward numerical implementations. One important observation from the physical approach is that the analysis should always be done for the specific geometry and parameters of the experiment. Here, we illustrate these methods on axial deformations of a cylindrical rock sample in the lab. A uniform, isotropic elastic rock with a thermoelastic effect is considered in four types of experiments: 1) axial extension with free transverse boundary, 2) pure axial extension with constrained transverse boundary, 3) pure bulk expansion, and 4) axial loading harmonically varying with time. In each of these cases, an

  14. A physical model of Titan's clouds

    NASA Technical Reports Server (NTRS)

    Toon, O. B.; Pollack, J. B.; Turco, R. P.

    1980-01-01

    A physical model of the formation and growth of aerosols in the atmosphere of Titan has been constructed in light of the observed correlation between variations in Titan's albedo and the sunspot cycle. The model was developed to fit spectral observations of deep methane bands, pressures, temperature distributions, and cloud structure, and is based on a one-dimensional physical-chemical model developed to simulate the earth's stratospheric aerosol layer. Sensitivity tests reveal the model parameters to be relatively insensitive to particle shape but sensitive to particle density, with high particle densities requiring larger aerosol mass production rates to produce compatible clouds. Solution of the aerosol continuity equations for particles of sizes 13 A to about 3 microns indicates the importance of a warm upper atmosphere and a high-altitude mass injection layer, and the production of aerosols at very low aerosol optical depths. Limits are obtained for the chemical production of aerosol mass and the eddy diffusion coefficient, and it is found that an increase in mass input causes a decrease in mean particle size.

  15. Future high precision experiments and new physics beyond Standard Model

    SciTech Connect

    Luo, Mingxing

    1993-04-01

    High precision (< 1%) electroweak experiments that have been done or are likely to be done in this decade are examined on the basis of Standard Model (SM) predictions of fourteen weak neutral current observables and fifteen W and Z properties to the one-loop level, the implications of the corresponding experimental measurements to various types of possible new physics that enter at the tree or loop level were investigated. Certain experiments appear to have special promise as probes of the new physics considered here.

  16. Future high precision experiments and new physics beyond Standard Model

    SciTech Connect

    Luo, Mingxing.

    1993-01-01

    High precision (< 1%) electroweak experiments that have been done or are likely to be done in this decade are examined on the basis of Standard Model (SM) predictions of fourteen weak neutral current observables and fifteen W and Z properties to the one-loop level, the implications of the corresponding experimental measurements to various types of possible new physics that enter at the tree or loop level were investigated. Certain experiments appear to have special promise as probes of the new physics considered here.

  17. A Physical Model of Electron Radiation Belts of Saturn

    NASA Astrophysics Data System (ADS)

    Lorenzato, L.; Sicard-Piet, A.; Bourdarie, S.

    2012-04-01

    Radiation belts causes irreversible damages on on-board instruments materials. That's why for two decades, ONERA proposes studies about radiation belts of magnetized planets. First, in the 90's, the development of a physical model, named Salammbô, carried out a model of the radiation belts of the Earth. Then, for few years, analysis of the magnetosphere of Jupiter and in-situ data (Pioneer, Voyager, Galileo) allow to build a physical model of the radiation belts of Jupiter. Enrolling on the Cassini age and thanks to all information collected, this study permits to adapt Salammbô jovian radiation belts model to the case of Saturn environment. Indeed, some physical processes present in the kronian magnetosphere are similar to those present in the magnetosphere of Jupiter (radial diffusion; interaction of energetic electrons with rings, moons, atmosphere; synchrotron emission). However, some physical processes have to be added to the kronian model (compared to the jovian model) because of the particularity of the magnetosphere of Saturn: interaction of energetic electrons with neutral particles from Enceladus, and wave-particle interaction. This last physical process has been studied in details with the analysis of CASSINI/RPWS (Radio and Plasma Waves Science) data. The major importance of the wave particles interaction is now well known in the case of the radiation belts of the Earth but it is important to investigate on its role in the case of Saturn. So, importance of each physical process has been studied and analysis of Cassini MIMI-LEMMS and CAPS data allows to build a model boundary condition (at L = 6). Finally, results of this study lead to a kronian electrons radiation belts model including radial diffusion, interactions of energetic electrons with rings, moons and neutrals particles and wave-particle interaction (interactions of electrons with atmosphere particles and synchrotron emission are too weak to be taken into account in this model). Then, to

  18. Beyond the standard model of particle physics.

    PubMed

    Virdee, T S

    2016-08-28

    The Large Hadron Collider (LHC) at CERN and its experiments were conceived to tackle open questions in particle physics. The mechanism of the generation of mass of fundamental particles has been elucidated with the discovery of the Higgs boson. It is clear that the standard model is not the final theory. The open questions still awaiting clues or answers, from the LHC and other experiments, include: What is the composition of dark matter and of dark energy? Why is there more matter than anti-matter? Are there more space dimensions than the familiar three? What is the path to the unification of all the fundamental forces? This talk will discuss the status of, and prospects for, the search for new particles, symmetries and forces in order to address the open questions.This article is part of the themed issue 'Unifying physics and technology in light of Maxwell's equations'. PMID:27458261

  19. Beyond the standard model of particle physics.

    PubMed

    Virdee, T S

    2016-08-28

    The Large Hadron Collider (LHC) at CERN and its experiments were conceived to tackle open questions in particle physics. The mechanism of the generation of mass of fundamental particles has been elucidated with the discovery of the Higgs boson. It is clear that the standard model is not the final theory. The open questions still awaiting clues or answers, from the LHC and other experiments, include: What is the composition of dark matter and of dark energy? Why is there more matter than anti-matter? Are there more space dimensions than the familiar three? What is the path to the unification of all the fundamental forces? This talk will discuss the status of, and prospects for, the search for new particles, symmetries and forces in order to address the open questions.This article is part of the themed issue 'Unifying physics and technology in light of Maxwell's equations'.

  20. Investigation of physical and chemical stability of ointment with herbals.

    PubMed

    Zdoryk, Oleksandr A; Khokhlova, Kateryna O; Georgiyants, Victoriya A; Vyshnevska, Liliia I

    2014-01-01

    The physical and chemical stability of a stock preparation ointment with active ingredients-herbal tinctures of calendula and arnica-for the treatment of hemorrhoids was studied. Evaluations for physical and chemical stability were performed initially and throughout the storage period. Physical stability of the ointment was assessed by means of visual observation in normal room light. Throughout the study period, the physical appearance of the ointment did not change. The chemical stability of the ointment was evaluated by means of a stability-indicating, thin-layer chromatography analytical technique. The shelf-life was found to be one month at 25 degrees C +/- 2 degrees C/60% RH and two months at 5 degrees C +/- 3 degrees C, when protected from light. PMID:25306773

  1. Investigation of physical and chemical stability of ointment with herbals.

    PubMed

    Zdoryk, Oleksandr A; Khokhlova, Kateryna O; Georgiyants, Victoriya A; Vyshnevska, Liliia I

    2014-01-01

    The physical and chemical stability of a stock preparation ointment with active ingredients-herbal tinctures of calendula and arnica-for the treatment of hemorrhoids was studied. Evaluations for physical and chemical stability were performed initially and throughout the storage period. Physical stability of the ointment was assessed by means of visual observation in normal room light. Throughout the study period, the physical appearance of the ointment did not change. The chemical stability of the ointment was evaluated by means of a stability-indicating, thin-layer chromatography analytical technique. The shelf-life was found to be one month at 25 degrees C +/- 2 degrees C/60% RH and two months at 5 degrees C +/- 3 degrees C, when protected from light.

  2. Models in Physics, Models for Physics Learning, and Why the Distinction May Matter in the Case of Electric Circuits

    ERIC Educational Resources Information Center

    Hart, Christina

    2008-01-01

    Models are important both in the development of physics itself and in teaching physics. Historically, the consensus models of physics have come to embody particular ontological assumptions and epistemological commitments. Educators have generally assumed that the consensus models of physics, which have stood the test of time, will also work well…

  3. Structured physical examination data: a modeling challenge.

    PubMed

    Doupi, P; van Ginneken, A M

    2001-01-01

    The success of systems facilitating collection of structured data by clinicians is largely dependent on the flexibility of the interface. The Open Record for CAre (ORCA) makes use of a generic model to support knowledge-based structured data entry for a variety of medical domains. An endeavor undertaken recently aimed to cover the broader area of Physical Examination by expanding the contents of the knowledge base. The model was found to be adequately expressive for supporting this task. Maintaining the balance between flexibility of the interface and constraints dictated by reliable retrieval, however, proved to be a considerable challenge. In this paper we illustrate through specific examples the effect of this trade off on the modeling process, together with the rationale for the chosen solutions and suggestions for future research focus.

  4. Physical modelling of the nuclear pore complex

    PubMed Central

    Fassati, Ariberto; Ford, Ian J.; Hoogenboom, Bart W.

    2013-01-01

    Physically interesting behaviour can arise when soft matter is confined to nanoscale dimensions. A highly relevant biological example of such a phenomenon is the Nuclear Pore Complex (NPC) found perforating the nuclear envelope of eukaryotic cells. In the central conduit of the NPC, of ∼30–60 nm diameter, a disordered network of proteins regulates all macromolecular transport between the nucleus and the cytoplasm. In spite of a wealth of experimental data, the selectivity barrier of the NPC has yet to be explained fully. Experimental and theoretical approaches are complicated by the disordered and heterogeneous nature of the NPC conduit. Modelling approaches have focused on the behaviour of the partially unfolded protein domains in the confined geometry of the NPC conduit, and have demonstrated that within the range of parameters thought relevant for the NPC, widely varying behaviour can be observed. In this review, we summarise recent efforts to physically model the NPC barrier and function. We illustrate how attempts to understand NPC barrier function have employed many different modelling techniques, each of which have contributed to our understanding of the NPC.

  5. Ionospheric irregularity physics modelling. Memorandum report

    SciTech Connect

    Ossakow, S.L.; Keskinen, M.J.; Zalesak, S.T.

    1982-02-09

    Theoretical and numerical simulation techniques have been employed to study ionospheric F region plasma cloud striation phenomena, equatorial spread F phenomena, and high latitude diffuse auroral F region irregularity phenomena. Each of these phenomena can cause scintillation effects. The results and ideas from these studies are state-of-the-art, agree well with experimental observations, and have induced experimentalists to look for theoretically predicted results. One conclusion that can be drawn from these studies is that ionospheric irregularity phenomena can be modelled from a first principles physics point of view. Theoretical and numerical simulation results from the aforementioned ionospheric irregularity areas will be presented.

  6. Physical modeling synthesis of recorder sound

    NASA Astrophysics Data System (ADS)

    Shiraiwa, Hiroko; Kishi, Kenshi; Nakamura, Isao

    2003-04-01

    A time-domain simulation of the soprano baroque recorder based on the digital waveguide model (DWM) and an air reed model is introduced. The air reed model is developed upon the negative acoustic displacement model (NADM), which was proposed for the organ flue-pipe simulation [Adachi, Proc. of ISMA 1997, pp. 251-260], based on the semiempirical model by Fletcher [Fletcher and Rossing, The Physics of Musical Instruments, 2nd ed. (Springer, Berlin, 2000)]. Two models are proposed to couple DWM and NADM. The jet amplification coefficient is remodeled for the application of NADM for the recorder, regarding the recent experimental reports [Yoshikawa and Arimoto, Proc. of ISMA 2001, pp. 309-312]. The simulation results are presented in terms of the mode transient characteristics and the spectral characteristics of the synthesized sounds. They indicate that the NADM is not sufficient to describe the realistic mode transient of the recorder, while the synthesized sounds maintained almost resemble timbre to the recorder sounds.

  7. Experimental Investigation of Iron Plasma Opacity Models

    SciTech Connect

    Bailey, J. E.; Rochau, G. A.; Hansen, S. B.; Nash, T. J.; Nielsen, D. S.; Lake, P. W.; Iglesias, C. A.; Mancini, R. C.; MacFarlane, J. J.; Golovkin, I.; Wang, P.; Blancard, C.; Cosse, Ph.; Faussurier, G.; Gilleron, F.; Pain, J. C.; Abdallah, J. Jr.; Pradhan, A. K.; Nahar, S. N.

    2009-09-10

    Recent experiments extended iron opacity model tests to temperatures above 150 eV for the first time. The experiments use the Z Facility to volumetrically heat a CH-tamped Fe/Mg plasma using x-rays. The frequency dependent sample transmission is measured by viewing a backlight through the sample. The plasma conditions are inferred from the Mg K-shell absorption. The strategy for this research is to examine the underlying physics within Fe opacity models by comparisons with the measured transmission. Physics topics of interest include charge state distribution, energy level structure, and line broadening. In this talk we discuss methods to exploit the data and advance understanding for these topics. In addition, we review new experiments under way to further improve the data and to achieve higher energy density conditions.

  8. Reappraising the Relationships between Physics Students' Mental Models and Predictions: An Example of Heat Convection

    ERIC Educational Resources Information Center

    Chiou, Guo-Li

    2013-01-01

    Although prediction is claimed to be a prime function of mental models, to what extent students can run their mental models to make predictions of physical phenomena remains uncertain. The purpose of this study, therefore, was first to investigate 30 physics students' mental models of heat convection, and then to examine the relationship between…

  9. The Effect of Physical Attractiveness of Models on Advertising Effectiveness for Male and Female Adolescents

    ERIC Educational Resources Information Center

    Tsai, Chia-Ching; Chang, Chih-Hsiang

    2007-01-01

    This study investigates the effect of advertising with physically attractive models on male and female adolescents. The findings suggest that highly attractive models are less effective than those who are normally attractive. Implications of social comparison are discussed.

  10. Investigating Student Ownership of Projects in Upper-Division Physics Laboratory Courses

    NASA Astrophysics Data System (ADS)

    Stanley, Jacob

    In undergraduate research experiences, student development of an identity as a scientist is coupled to their sense of ownership of their research projects. As a first step towards studying similar connections in physics laboratory courses, we investigate student ownership of projects in a lasers-based upper-division course. Students spent the final seven weeks of the semester working in groups on final projects of their choosing. Using data from the Project Ownership Survey and weekly student reflections, we investigate student ownership as it relates to students' personal agency, self-efficacy, peer interactions, and complex affective responses to challenges and successes. We present evidence of students' project ownership in an upper-division physics lab. Additionally, we propose a model for student development of ownership through cycles of frustration and excitement as students progress on their projects. This work was supported by NSF Grant Nos. DUE-1323101 and DUE-1334170.

  11. Investigating Students' Reflective Thinking in the Introductory Physics Course

    NASA Astrophysics Data System (ADS)

    Boudreaux, Andrew

    2010-10-01

    Over the past 30 years, physics education research has guided the development of instructional strategies that can significantly enhance students' functional understanding of concepts in introductory physics. Recently, attention has shifted to instructional goals that, while widely shared by teachers of physics, are often more implicit than explicit in our courses. These goals involve the expectations and attitudes that students have about what it means to learn and understand physics, together with the behaviors and actions students think they should engage in to accomplish this learning. Research has shown that these ``hidden'' elements of the curriculum are remarkably resistant to instruction. In fact, traditional physics courses tend to produce movement away from expert-like behaviors. At Western Washington University, we are exploring ways of promoting metacognition, an aspect of the hidden curriculum that involves the conscious monitoring of one's own thinking and learning. We have found that making this reflective thinking an explicit part of the course may not be enough: adequate framing and scaffolding may be necessary for students to meaningfully engage in metacognition. We have thus taken the basic approach of developing metacognition, like conceptual understanding, through guided inquiry. During our teaching experiments, we have collected written and video data, with twin goals of guiding iterative modifications to the instruction as well as contributing to the knowledge base about student metacognition in introductory physics. This talk will provide examples of metacognition activities from course assignments and labs, and will present written data to assess the effectiveness of instruction and to illustrate specific modes of students' reflective thinking.

  12. Investigating the impact of representation upon coarse-grained models

    NASA Astrophysics Data System (ADS)

    Foley, Thomas; Shell, M. Scott; Noid, William

    The first step in building a coarse-grained (CG) model is choosing a representation or `mapping' of the original system at a reduced resolution. In practice, the mapping is often chosen on the basis of `physical intuition.' Consequently this crucial step would greatly benefit from the development of systematic and principled methodologies. Accordingly, we have studied the relationship between the mapping and the resulting CG model. As a starting point, we have analytically derived, as a function of the CG mapping, the exact many-body potential of mean force (PMF) for the simple Gaussian Network Model (GNM) of protein fluctuations. We use this as a simple model for investigating the effect of the CG mapping upon the information loss and quality of the CG model. Moreover, by considering the GNM's for different proteins, we investigate the significance of high resolution structural features for the quality of the CG model. We acknowledge support from the NSF, Alfred P. Sloan Foundation, and KITP.

  13. Systems and models with anticipation in physics and its applications

    NASA Astrophysics Data System (ADS)

    Makarenko, A.

    2012-11-01

    Investigations of recent physics processes and real applications of models require the new more and more improved models which should involved new properties. One of such properties is anticipation (that is taking into accounting some advanced effects).It is considered the special kind of advanced systems - namely a strong anticipatory systems introduced by D. Dubois. Some definitions, examples and peculiarities of solutions are described. The main feature is presumable multivaluedness of the solutions. Presumable physical examples of such systems are proposed: self-organization problems; dynamical chaos; synchronization; advanced potentials; structures in micro-, meso- and macro- levels; cellular automata; computing; neural network theory. Also some applications for modeling social, economical, technical and natural systems are described.

  14. Evaluating performances of simplified physically based landslide susceptibility models.

    NASA Astrophysics Data System (ADS)

    Capparelli, Giovanna; Formetta, Giuseppe; Versace, Pasquale

    2015-04-01

    Rainfall induced shallow landslides cause significant damages involving loss of life and properties. Prediction of shallow landslides susceptible locations is a complex task that involves many disciplines: hydrology, geotechnical science, geomorphology, and statistics. Usually to accomplish this task two main approaches are used: statistical or physically based model. This paper presents a package of GIS based models for landslide susceptibility analysis. It was integrated in the NewAge-JGrass hydrological model using the Object Modeling System (OMS) modeling framework. The package includes three simplified physically based models for landslides susceptibility analysis (M1, M2, and M3) and a component for models verifications. It computes eight goodness of fit indices (GOF) by comparing pixel-by-pixel model results and measurements data. Moreover, the package integration in NewAge-JGrass allows the use of other components such as geographic information system tools to manage inputs-output processes, and automatic calibration algorithms to estimate model parameters. The system offers the possibility to investigate and fairly compare the quality and the robustness of models and models parameters, according a procedure that includes: i) model parameters estimation by optimizing each of the GOF index separately, ii) models evaluation in the ROC plane by using each of the optimal parameter set, and iii) GOF robustness evaluation by assessing their sensitivity to the input parameter variation. This procedure was repeated for all three models. The system was applied for a case study in Calabria (Italy) along the Salerno-Reggio Calabria highway, between Cosenza and Altilia municipality. The analysis provided that among all the optimized indices and all the three models, Average Index (AI) optimization coupled with model M3 is the best modeling solution for our test case. This research was funded by PON Project No. 01_01503 "Integrated Systems for Hydrogeological Risk

  15. Detailed Physical Trough Model for NREL's Solar Advisor Model: Preprint

    SciTech Connect

    Wagner, M. J.; Blair, N.; Dobos, A.

    2010-10-01

    Solar Advisor Model (SAM) is a free software package made available by the National Renewable Energy Laboratory (NREL), Sandia National Laboratory, and the US Department of Energy. SAM contains hourly system performance and economic models for concentrating solar power (CSP) systems, photovoltaic, solar hot-water, and generic fuel-use technologies. Versions of SAM prior to 2010 included only the parabolic trough model based on Excelergy. This model uses top-level empirical performance curves to characterize plant behavior, and thus is limited in predictive capability for new technologies or component configurations. To address this and other functionality challenges, a new trough model; derived from physical first principles was commissioned to supplement the Excelergy-based empirical model. This new 'physical model' approaches the task of characterizing the performance of the whole parabolic trough plant by replacing empirical curve-fit relationships with more detailed calculations where practical. The resulting model matches the annual performance of the SAM empirical model (which has been previously verified with plant data) while maintaining run-times compatible with parametric analysis, adding additional flexibility in modeled system configurations, and providing more detailed performance calculations in the solar field, power block, piping, and storage subsystems.

  16. Physics model for wringing of wet cloth

    NASA Astrophysics Data System (ADS)

    Dany Rahmayanti, Handika; Utami, Fisca Dian; Abdullah, Mikrajuddin

    2016-11-01

    One activity that has been performed by human beings for a long time is washing clothes. Before the invention of the washing machine, clothes were washed by hand and then wrung before drying in the open air. When observed carefully, the wringing of cloth presents some interesting phenomena. However, there are no reports on the physical modelling of this very old activity. This paper reports a simple model to explain the discharge of water from clothes when squeezed. A simple tool was also designed to retrieve data to confirm the theory. We found that the theoretical predictions accurately explained the experimental results. The experiments were conducted on two types of cloth: towels and batik cloth. We also obtained a universal curve to which all the data converged.

  17. Semi-Empirical Modeling of SLD Physics

    NASA Technical Reports Server (NTRS)

    Wright, William B.; Potapczuk, Mark G.

    2004-01-01

    The effects of supercooled large droplets (SLD) in icing have been an area of much interest in recent years. As part of this effort, the assumptions used for ice accretion software have been reviewed. A literature search was performed to determine advances from other areas of research that could be readily incorporated. Experimental data in the SLD regime was also analyzed. A semi-empirical computational model is presented which incorporates first order physical effects of large droplet phenomena into icing software. This model has been added to the LEWICE software. Comparisons are then made to SLD experimental data that has been collected to date. Results will be presented for the comparison of water collection efficiency, ice shape and ice mass.

  18. Emotional Arousal of Beginning Physics Teachers during Extended Experimental Investigations

    ERIC Educational Resources Information Center

    Ritchie, Stephen M.; Tobin, Kenneth; Sandhu, Maryam; Sandhu, Satwant; Henderson, Senka; Roth, Wolff-Michael

    2013-01-01

    Teachers often have difficulty implementing inquiry-based activities, leading to the arousal of negative emotions. In this multicase study of beginning physics teachers in Australia, we were interested in the extent to which their expectations were realized and how their classroom experiences while implementing extended experimental investigations…

  19. An Investigation of Physics Undergraduates' Attitudes towards Mathematics

    ERIC Educational Resources Information Center

    Symonds, Ria; Lawson, Duncan; Robinson, Carol

    2010-01-01

    In recent years, the failure rate on first-year mathematics modules on Physics courses at Loughborough University has given cause for concern. It was feared that failure in the first year would result in students performing poorly in future mathematics modules. Hence, a proactive support system was introduced for the mathematically less…

  20. Toward understanding writing to learn in physics: Investigating student writing

    NASA Astrophysics Data System (ADS)

    Demaree, Dedra

    It is received wisdom that writing in a discipline helps students learn the discipline, and millions of dollars have been committed at many universities to supporting such writing. We show that evidence for effectiveness is anecdotal, and that little data-based material informs these prejudices. This thesis begins the process of scientific study of writing in the discipline, in specific, in physics, and creates means to judge whether such writing is effective. The studies culminating in this thesis are an aggressive start to addressing these complex questions. Writing is often promoted as an activity that, when put into classrooms in specific disciplines, not only helps students learn to write in the methods of that discipline but also helps students learn content knowledge. Students at the Ohio State University are being asked to write more in introductory courses, and the Engineering schools want their students to have more writing skills for the job market. Combined with the desire of many educators to have students be able to explain the course content knowledge clearly, it would seem that writing activities would be important and useful in physics courses. However, the question of whether writing helps learning or whether students learn writing within a non-English classroom helps learning in the discipline are open to debate, and data are needed before such claims can be made. This thesis presents several studies aimed at understanding the correlation of writing and content, and tracking and characterizing student writing behaviors to see how they are impacted by writing in physics courses. It consists of four parts: summer and autumn 2005 focus on writing in introductory physics labs with and without explicit instruction, while winter and spring 2006 focus on tracking and analyzing student writing and revising behavior in Physics by Inquiry (PbI). With these related projects, we establish three main results. First, there is a need for quantitative studies of

  1. Physics-based models of the plasmasphere

    SciTech Connect

    Jordanova, Vania K; Pierrard, Vivane; Goldstein, Jerry; Andr'e, Nicolas; Lemaire, Joseph F; Liemohn, Mike W; Matsui, H

    2008-01-01

    We describe recent progress in physics-based models of the plasmasphere using the Auid and the kinetic approaches. Global modeling of the dynamics and inAuence of the plasmasphere is presented. Results from global plasmasphere simulations are used to understand and quantify (i) the electric potential pattern and evolution during geomagnetic storms, and (ii) the inAuence of the plasmasphere on the excitation of electromagnetic ion cyclotron (ElvIIC) waves a.nd precipitation of energetic ions in the inner magnetosphere. The interactions of the plasmasphere with the ionosphere a.nd the other regions of the magnetosphere are pointed out. We show the results of simulations for the formation of the plasmapause and discuss the inAuence of plasmaspheric wind and of ultra low frequency (ULF) waves for transport of plasmaspheric material. Theoretical formulations used to model the electric field and plasma distribution in the plasmasphere are given. Model predictions are compared to recent CLUSTER and MAGE observations, but also to results of earlier models and satellite observations.

  2. 3-D physical models of amitosis (cytokinesis).

    PubMed

    Cheng, Kang; Zou, Changhua

    2005-01-01

    Based on Newton's laws, extended Coulomb's law and published biological data, we develop our 3-D physical models of natural and normal amitosis (cytokinesis), for prokaryotes (bacterial cells) in M phase. We propose following hypotheses: Chromosome rings exclusion: No normally and naturally replicated chromosome rings (RCR) can occupy the same prokaryote, a bacterial cell. The RCR produce spontaneous and strong electromagnetic fields (EMF), that can be alternated environmentally, in protoplasm and cortex. The EMF is approximately a repulsive quasi-static electric (slowly variant and mostly electric) field (EF). The EF forces between the RCR are strong enough, and orderly accumulate contractile proteins that divide the procaryotes in the cell cortex of division plane or directly split the cell compartment envelope longitudinally. The radial component of the EF forces could also make furrows or cleavages of procaryotes. The EF distribution controls the protoplasm partition and completes the amitosis (cytokinesis). After the cytokinesis, the spontaneous and strong EF disappear because the net charge accumulation becomes weak, in the protoplasm. The exclusion is because the two sets of informative objects (RCR) have identical DNA codes information and they are electro magnetically identical, therefore they repulse from each other. We also compare divisions among eukaryotes, prokaryotes, mitochondria and chloroplasts and propose our hypothesis: The principles of our models are applied to divisions of mitochondria and chloroplasts of eucaryotes too because these division mechanisms are closer than others in a view of physics. Though we develop our model using 1 division plane (i.e., 1 cell is divided into 2 cells) as an example, the principle of our model is applied to the cases with multiple division planes (i.e., 1 cell is divided into multiple cells) too.

  3. Propulsion Physics Using the Chameleon Density Model

    NASA Technical Reports Server (NTRS)

    Robertson, Glen A.

    2011-01-01

    To grow as a space faring race, future spaceflight systems will require a new theory of propulsion. Specifically one that does not require mass ejection without limiting the high thrust necessary to accelerate within or beyond our solar system and return within a normal work period or lifetime. The Chameleon Density Model (CDM) is one such model that could provide new paths in propulsion toward this end. The CDM is based on Chameleon Cosmology a dark matter theory; introduced by Khrouy and Weltman in 2004. Chameleon as it is hidden within known physics, where the Chameleon field represents a scalar field within and about an object; even in the vacuum. The CDM relates to density changes in the Chameleon field, where the density changes are related to matter accelerations within and about an object. These density changes in turn change how an object couples to its environment. Whereby, thrust is achieved by causing a differential in the environmental coupling about an object. As a demonstration to show that the CDM fits within known propulsion physics, this paper uses the model to estimate the thrust from a solid rocket motor. Under the CDM, a solid rocket constitutes a two body system, i.e., the changing density of the rocket and the changing density in the nozzle arising from the accelerated mass. Whereby, the interactions between these systems cause a differential coupling to the local gravity environment of the earth. It is shown that the resulting differential in coupling produces a calculated value for the thrust near equivalent to the conventional thrust model used in Sutton and Ross, Rocket Propulsion Elements. Even though imbedded in the equations are the Universe energy scale factor, the reduced Planck mass and the Planck length, which relates the large Universe scale to the subatomic scale.

  4. Physical modeling of traffic with stochastic cellular automata

    SciTech Connect

    Schreckenberg, M.; Nagel, K. |

    1995-09-01

    A new type of probabilistic cellular automaton for the physical description of single and multilane traffic is presented. In this model space, time and the velocity of the cars are represented by integer numbers (as usual in cellular automata) with local update rules for the velocity. The model is very efficient for both numerical simulations and analytical investigations. The numerical results from extensive simulations reproduce very well data taken from real traffic (e.g. fundamental diagrams). Several analytical results for the model are presented as well as new approximation schemes for stationary traffic. In addition the relation to continuum hydrodynamic theory (Lighthill-Whitham) and the follow-the-leader models is discussed. The model is part of an interdisciplinary research program in Northrhine-Westfalia (``NRW Forschungsverbund Verkehrssimulation``) for the construction of a large scale microsimulation model for network traffic, supported by the government of NRW.

  5. Investigation of physical properties of TiO2 nanolayers

    NASA Astrophysics Data System (ADS)

    Struk, Przemyslaw; Pustelny, Tadeusz

    2015-12-01

    We present applications of titanium dioxide wide bandgap oxide semiconductor and its application in integrated optics devices. The paper is focus on research of physical properties TiO2 such as: spectral transmittance, refractive index, extinction coefficient in the UV-VIS-IR range of light as well as surface topography. In addition we show the numerical calculation and optical characterization of fabricated optical planar waveguide based on TiO2.

  6. Investigations in Experimental and Theoretical High Energy Physics

    SciTech Connect

    Krennrich, Frank

    2013-07-29

    We report on the work done under DOE grant DE-FG02-01ER41155. The experimental tasks have ongoing efforts at CERN (ATLAS), the Whipple observatory (VERITAS) and R&D work on dual readout calorimetry and neutrino-less double beta decay. The theoretical task emphasizes the weak interaction and in particular CP violation and neutrino physics. The detailed descriptions of the final report on each project are given under the appropriate task section of this report.

  7. Tactile Teaching: Exploring Protein Structure/Function Using Physical Models

    ERIC Educational Resources Information Center

    Herman, Tim; Morris, Jennifer; Colton, Shannon; Batiza, Ann; Patrick, Michael; Franzen, Margaret; Goodsell, David S.

    2006-01-01

    The technology now exists to construct physical models of proteins based on atomic coordinates of solved structures. We review here our recent experiences in using physical models to teach concepts of protein structure and function at both the high school and the undergraduate levels. At the high school level, physical models are used in a…

  8. Computer Integrated Manufacturing: Physical Modelling Systems Design. A Personal View.

    ERIC Educational Resources Information Center

    Baker, Richard

    A computer-integrated manufacturing (CIM) Physical Modeling Systems Design project was undertaken in a time of rapid change in the industrial, business, technological, training, and educational areas in Australia. A specification of a manufacturing physical modeling system was drawn up. Physical modeling provides a flexibility and configurability…

  9. Fuzzy modelling of Atlantic salmon physical habitat

    NASA Astrophysics Data System (ADS)

    St-Hilaire, André; Mocq, Julien; Cunjak, Richard

    2015-04-01

    Fish habitat models typically attempt to quantify the amount of available river habitat for a given fish species for various flow and hydraulic conditions. To achieve this, information on the preferred range of values of key physical habitat variables (e.g. water level, velocity, substrate diameter) for the targeted fishs pecies need to be modelled. In this context, we developed several habitat suitability indices sets for three Atlantic salmon life stages (young-of-the-year (YOY), parr, spawning adults) with the help of fuzzy logic modeling. Using the knowledge of twenty-seven experts, from both sides of the Atlantic Ocean, we defined fuzzy sets of four variables (depth, substrate size, velocity and Habitat Suitability Index, or HSI) and associated fuzzy rules. When applied to the Romaine River (Canada), median curves of standardized Weighted Usable Area (WUA) were calculated and a confidence interval was obtained by bootstrap resampling. Despite the large range of WUA covered by the expert WUA curves, confidence intervals were relatively narrow: an average width of 0.095 (on a scale of 0 to 1) for spawning habitat, 0.155 for parr rearing habitat and 0.160 for YOY rearing habitat. When considering an environmental flow value corresponding to 90% of the maximum reached by WUA curve, results seem acceptable for the Romaine River. Generally, this proposed fuzzy logic method seems suitable to model habitat availability for the three life stages, while also providing an estimate of uncertainty in salmon preferences.

  10. Evaluating nuclear physics inputs in core-collapse supernova models

    SciTech Connect

    Lentz, Eric J; Hix, William Raphael; Baird, Mark L; Messer, Bronson; Mezzacappa, Anthony

    2010-01-01

    Core-collapse supernova models depend on the details of the nuclear and weak interaction physics inputs just as they depend on the details of the macroscopic physics (transport, hydrodynamics, etc.), numerical methods, and progenitors. We present the results of our ongoing comparison studies of nuclear and weak interaction physics inputs to core collapse supernova models using the spherically-symmetric, general relativistic, neutrino radiation hydrodynamics code Agile-Boltztran. We focus on comparisons of the effects of the nuclear EoS and the effects of improving the opacities, particularly neutrino--nucleon interactions. We present the results of our ongoing comparison studies of nuclear and weak interaction physics inputs to core collapse supernova models using the spherically-symmetric, general relativistic, neutrino radiation hydrodynamics code Agile-Boltztran. We focus on comparisons of the effects of the nuclear EoS and the effects of improving the opacities, particularly neutrino--nucleon interactions. We also investigate the feedback between different EoSs and opacities in the context of different progenitors.

  11. Physical and Chemical Investigations of Selected Buckminsterfullerene-Based Materials

    NASA Astrophysics Data System (ADS)

    Dykes, John West

    Studies of materials based on the molecule C _{60} have been performed in three complementary areas; namely, the reaction and passivation of aluminum with C_{60}, nanometer-scale materials engineering utilizing C _{60}, and the critical magnetic fields of superconducting rm K_3C _{60}. The majority of the C _{60} powder used in the investigations was produced in-house. Steps of the process for generating C_{60} from graphitic carbon are given. Fullerene-containing soot was generated in a modified plasma-arc reactor. Fullerenes were separated from soot using Soxhlet extraction. Lastly, C _{60} was separated from the other fullerenes using liquid chromatography. Experiments on the reaction of C_ {60} with aluminum were done on aluminum foils in ultra-high vacuum using Auger spectroscopy, temperature -programmed desorption, photoluminescence, and soft x-ray photoelectron spectroscopy. Strong bonding between C _{60} and aluminum is reported. Results show that when multilayer C_{60} is evaporated onto clean aluminum, all molecules except the monolayer in contact with the aluminum desorb when the sample is heated to 578 K. Photoelectron spectroscopy measurements indicate that electrons transfer from C _{60} to the aluminum at the interface. Additionally, the data may reveal that C_{60} molecules diffuse intact into the aluminum bulk when heating to the aluminum surface melting temperature occurs. The ease of preparing monolayer C_ {60} coverage on a surface by multilayer C_{60} evaporation followed by sublimation of all molecules but those in direct surface contact was examined for the preparation of multilayer and binding structures. The viability of the technique was not definitive. However, Fe/C_{60 }/Fe trilayers may show antiferromagnetic coupling and hence giant magnetoresistance at room temperature. Further, the use of C_{60} to bond metals to semiconductors is related. To resolve superconducting properties, an examination of rm K_3C_{60} was initiated. Most of

  12. Compass models: Theory and physical motivations

    NASA Astrophysics Data System (ADS)

    Nussinov, Zohar; van den Brink, Jeroen

    2015-01-01

    Compass models are theories of matter in which the couplings between the internal spin (or other relevant field) components are inherently spatially (typically, direction) dependent. A simple illustrative example is furnished by the 90° compass model on a square lattice in which only couplings of the form τixτjx (where {τia}a denote Pauli operators at site i ) are associated with nearest-neighbor sites i and j separated along the x axis of the lattice while τiyτjy couplings appear for sites separated by a lattice constant along the y axis. Similar compass-type interactions can appear in diverse physical systems. For instance, compass models describe Mott insulators with orbital degrees of freedom where interactions sensitively depend on the spatial orientation of the orbitals involved as well as the low-energy effective theories of frustrated quantum magnets, and a host of other systems such as vacancy centers, and cold atomic gases. The fundamental interdependence between internal (spin, orbital, or other) and external (i.e., spatial) degrees of freedom which underlies compass models generally leads to very rich behaviors, including the frustration of (semi-)classical ordered states on nonfrustrated lattices, and to enhanced quantum effects, prompting, in certain cases, the appearance of zero-temperature quantum spin liquids. As a consequence of these frustrations, new types of symmetries and their associated degeneracies may appear. These intermediate symmetries lie midway between the extremes of global symmetries and local gauge symmetries and lead to effective dimensional reductions. In this article, compass models are reviewed in a unified manner, paying close attention to exact consequences of these symmetries and to thermal and quantum fluctuations that stabilize orders via order-out-of-disorder effects. This is complemented by a survey of numerical results. In addition to reviewing past works, a number of other models are introduced and new results

  13. Satellite attitude motion models for capture and retrieval investigations

    NASA Technical Reports Server (NTRS)

    Cochran, John E., Jr.; Lahr, Brian S.

    1986-01-01

    The primary purpose of this research is to provide mathematical models which may be used in the investigation of various aspects of the remote capture and retrieval of uncontrolled satellites. Emphasis has been placed on analytical models; however, to verify analytical solutions, numerical integration must be used. Also, for satellites of certain types, numerical integration may be the only practical or perhaps the only possible method of solution. First, to provide a basis for analytical and numerical work, uncontrolled satellites were categorized using criteria based on: (1) orbital motions, (2) external angular momenta, (3) internal angular momenta, (4) physical characteristics, and (5) the stability of their equilibrium states. Several analytical solutions for the attitude motions of satellite models were compiled, checked, corrected in some minor respects and their short-term prediction capabilities were investigated. Single-rigid-body, dual-spin and multi-rotor configurations are treated. To verify the analytical models and to see how the true motion of a satellite which is acted upon by environmental torques differs from its corresponding torque-free motion, a numerical simulation code was developed. This code contains a relatively general satellite model and models for gravity-gradient and aerodynamic torques. The spacecraft physical model for the code and the equations of motion are given. The two environmental torque models are described.

  14. The Usability of a Commercial Game Physics Engine to Develop Physics Educational Materials: An Investigation

    ERIC Educational Resources Information Center

    Price, Colin B.

    2008-01-01

    Commercial computer games contain "physics engine" components, responsible for providing realistic interactions among game objects. The question naturally arises of whether these engines can be used to develop educational materials for high school and university physics education. To answer this question, the author's group recently conducted a…

  15. Physical Activity during Physical Education Lessons: A Qualitative Investigation of Australian PE Teacher Perceptions

    ERIC Educational Resources Information Center

    Bennie, Andrew; Langan, Edel

    2015-01-01

    School physical education (PE) experiences play a critical role in adolescents' physical activity (PA) levels. Teachers are crucial to students' initial experiences in PA; however, limited research has explored teachers' perspectives about PA during PE using in-depth qualitative research techniques. We conducted interviews with 25 current…

  16. A Holoinformational Model of the Physical Observer

    NASA Astrophysics Data System (ADS)

    Biase, Francisco Di

    2013-09-01

    The author proposes a holoinformational view of the observer based, on the holonomic theory of brain/mind function and quantum brain dynamics developed by Karl Pribram, Sir John Eccles, R.L. Amoroso, Hameroff, Jibu and Yasue, and in the quantumholographic and holomovement theory of David Bohm. This conceptual framework is integrated with nonlocal information properties of the Quantum Field Theory of Umesawa, with the concept of negentropy, order, and organization developed by Shannon, Wiener, Szilard and Brillouin, and to the theories of self-organization and complexity of Prigogine, Atlan, Jantsch and Kauffman. Wheeler's "it from bit" concept of a participatory universe, and the developments of the physics of information made by Zureck and others with the concepts of statistical entropy and algorithmic entropy, related to the number of bits being processed in the mind of the observer are also considered. This new synthesis gives a self-organizing quantum nonlocal informational basis for a new model of awareness in a participatory universe. In this synthesis, awareness is conceived as meaningful quantum nonlocal information interconnecting the brain and the cosmos, by a holoinformational unified field (integrating nonlocal holistic (quantum) and local (Newtonian). We propose that the cosmology of the physical observer is this unified nonlocal quantum-holographic cosmos manifesting itself through awareness, interconnected in a participatory holistic and indivisible way the human mind-brain to all levels of the self-organizing holographic anthropic multiverse.

  17. An investigation of the theoretical content of physical activity brochures

    PubMed Central

    Gainforth, Heather L.; Barg, Carolyn J.; Latimer, Amy E.; Schmid, Kristina L.; O'Malley, Deborah; Salovey, Peter

    2011-01-01

    New evidence-based physical activity guidelines and recommendations for constructing messages supplementing the guidelines have been put forth. As well, recent reviewshave identified theoretical constructs that hold promise as targets for intervention: self-regulation, outcome expectancies and self-efficacy. The purpose of this study was to examine the integration of messages targeting self-regulation, self-efficacy and outcome expectancies in existing physical activity brochures. Twenty-two PA brochures from Canadian and American National Health Organizations were assessed for their use self-efficacy, self-regulatory processes and outcome expectancies. Brochures were analyzed line-by-line using a modified version of the validated Content Analysis Approach to Theory-Specified Persuasive Educational Communication (CAATSPEC; Abraham et al., 2007). One third of the brochures were coded by two independent raters coded a third of the brochures (n = 7). Inter-rater reliability was acceptable for 17 of the 20 categories (rs> .79). Discrepancies in all categories were discussed and agreement was reached. The remaining brochures were coded by one of the two raters. Usage of thethree key theoretical constructs accounted for only 36.43% of brochure content (20.23% self-efficacy, 10.40% outcome expectancies, 5.80% self-regulation). Brochures lacked the use of a variety of theoretical strategies, specifically goal-setting, planning and verbal persuasion and rarely highlighted the affective benefits of physical activity. In the future brochures should aim to place increased emphasis on self-regulation, self-efficacy, and affective outcome expectancies. PMID:22125418

  18. Modelling urban rainfall-runoff responses using an experimental, two-tiered physical modelling environment

    NASA Astrophysics Data System (ADS)

    Green, Daniel; Pattison, Ian; Yu, Dapeng

    2016-04-01

    Surface water (pluvial) flooding occurs when rainwater from intense precipitation events is unable to infiltrate into the subsurface or drain via natural or artificial drainage channels. Surface water flooding poses a serious hazard to urban areas across the world, with the UK's perceived risk appearing to have increased in recent years due to surface water flood events seeming more severe and frequent. Surface water flood risk currently accounts for 1/3 of all UK flood risk, with approximately two million people living in urban areas at risk of a 1 in 200-year flood event. Research often focuses upon using numerical modelling techniques to understand the extent, depth and severity of actual or hypothetical flood scenarios. Although much research has been conducted using numerical modelling, field data available for model calibration and validation is limited due to the complexities associated with data collection in surface water flood conditions. Ultimately, the data which numerical models are based upon is often erroneous and inconclusive. Physical models offer a novel, alternative and innovative environment to collect data within, creating a controlled, closed system where independent variables can be altered independently to investigate cause and effect relationships. A physical modelling environment provides a suitable platform to investigate rainfall-runoff processes occurring within an urban catchment. Despite this, physical modelling approaches are seldom used in surface water flooding research. Scaled laboratory experiments using a 9m2, two-tiered 1:100 physical model consisting of: (i) a low-cost rainfall simulator component able to simulate consistent, uniformly distributed (>75% CUC) rainfall events of varying intensity, and; (ii) a fully interchangeable, modular plot surface have been conducted to investigate and quantify the influence of a number of terrestrial and meteorological factors on overland flow and rainfall-runoff patterns within a modelled

  19. Physical and Statistical Modeling of Saturn's Troposphere

    NASA Astrophysics Data System (ADS)

    Yanamandra-Fisher, Padmavati A.; Braverman, Amy J.; Orton, Glenn S.

    2002-12-01

    The 5.2-μm atmospheric window on Saturn is dominated by thermal radiation and weak gaseous absorption, with a 20% contribution from sunlight reflected from clouds. The striking variability displayed by Saturn's clouds at 5.2 μm and the detection of PH3 (an atmospheric tracer) variability near or below the 2-bar level and possibly at lower pressures provide salient constraints on the dynamical organization of Saturn's atmosphere by constraining the strength of vertical motions at two levels across the disk. We analyse the 5.2-μm spectra of Saturn by utilising two independent methods: (a) physical models based on the relevant atmospheric parameters and (b) statistical analysis, based on principal components analysis (PCA), to determine the influence of the variation of phosphine and the opacity of clouds deep within Saturn's atmosphere to understand the dynamics in its atmosphere.

  20. Outstanding questions: physics beyond the Standard Model.

    PubMed

    Ellis, John

    2012-02-28

    The Standard Model of particle physics agrees very well with experiment, but many important questions remain unanswered, among them are the following. What is the origin of particle masses and are they due to a Higgs boson? How does one understand the number of species of matter particles and how do they mix? What is the origin of the difference between matter and antimatter, and is it related to the origin of the matter in the Universe? What is the nature of the astrophysical dark matter? How does one unify the fundamental interactions? How does one quantize gravity? In this article, I introduce these questions and discuss how they may be addressed by experiments at the Large Hadron Collider, with particular attention to the search for the Higgs boson and supersymmetry. PMID:22253238

  1. [Physical reproduction of cardiac sutures. A new field of investigation in cardiology].

    PubMed

    Mirochnik, N; Hagège, A; Zacouto, F; Guérot, C

    2000-10-01

    A new technique of physical reproduction of cardiac anatomy has been developed from volumetric data and its practical value assessed in cardiological practice. The acquisition of the volumetric data was by 3D echocardiography. Parallel and equidistant 2D views were selected from this information. The images were printed at a scale adjusted to the true dimensions of the structures of interest and then stuck on a support, the thickness of which was identical to the distance between the views, and the slices were superimposed while respecting the initial orientation. This technique has been adapted secondarily to modern industrial processes of rapid prototyping (3D printing and powdering) allowing automatic tooling of models. Several physical models have been made: whole heart in end diastole, mitral valve stenosis and prolapse, atrial septal defect with insertion of a percutaneous prosthetic device, great vessels at the base of the heart. There are many possible cardiological applications of physical models: investigation of complex cardiac disease, pre- and per-operative simulation of surgical procedures, elaboration of prosthetic material, physiopathological studies, teaching and training, patient information.

  2. Investigating ICRF Core Physics with a Hybrid Method using δf Particles

    NASA Astrophysics Data System (ADS)

    Austin, T. M.; Smithe, D. N.

    2011-12-01

    Particle-in-cell simulations of ICRF core physics yield a significant amount of noise that can overwhelm the low amplitude signals associated with ICRH. To overcome this noise, we employ a hybrid approach that uses a fluid model for electrons and the delta-f particle-in-cell (DFPIC) method for ions. Noise is reduced to a level well below the amplitude of the signal and time steps are permitted to go beyond the electron time scales. With this formulation we have explored minority heating scenarios in Alcator C-Mod and high harmonic heating scenarios in NSTX. We can also employ the fluid model for both electrons and ions to investigate cold plasma scenarios. Here we examine ion test particles with particular attention paid to particle paths near resonance layers. We present our technique for investigating full particle orbits from a single toroidal mode expansion.

  3. Investigating the Impact of Teachers' Physics CK on Students Outcomes

    ERIC Educational Resources Information Center

    Ohle, Annika; Boone, William J.; Fischer, Hans E.

    2015-01-01

    Decreasing student interest and achievement during the transition from elementary to secondary school is an international problem, especially in science education. The question of what factors influence this decline has been a widely discussed topic. This study focuses on investigating the relationship of elementary school teachers' content…

  4. A Conceptual Model of Observed Physical Literacy

    ERIC Educational Resources Information Center

    Dudley, Dean A.

    2015-01-01

    Physical literacy is a concept that is gaining greater acceptance around the world with the United Nations Educational, Cultural, and Scientific Organization (2013) recognizing it as one of several central tenets in a quality physical education framework. However, previous attempts to understand progression in physical literacy learning have been…

  5. Physical modeling of transverse drainage mechanisms

    NASA Astrophysics Data System (ADS)

    Douglass, J. C.; Schmeeckle, M. W.

    2005-12-01

    Streams that incise across bedrock highlands such as anticlines, upwarps, cuestas, or horsts are termed transverse drainages. Their relevance today involves such diverse matters as highway and dam construction decisions, location of wildlife corridors, better-informed sediment budgets, and detailed studies into developmental histories of late Cenozoic landscapes. The transient conditions responsible for transverse drainage incision have been extensively studied on a case-by-case basis, and the dominate mechanisms proposed include: antecedence, superimposition, overflow, and piracy. Modeling efforts have been limited to antecedence, and such the specific erosional conditions required for transverse drainage incision, with respect to the individual mechanisms, remains poorly understood. In this study, fifteen experiments attempted to simulate the four mechanisms and constructed on a 9.15 m long, 2.1 m wide, and 0.45 m deep stream table. Experiments lasted between 50 and 220 minutes. The stream table was filled with seven tons of sediment consisting of a silt and clay (30%) and a fine to coarse sand (70%) mixture. The physical models highlighted the importance of downstream aggradation with regard to antecedent incision versus possible defeat and diversion. The overflow experiments indicate that retreating knickpoints across a basin outlet produce a high probability of downstream flooding when associated with a deep lake. Misters used in a couple of experiments illustrate a potential complication with regard to headward erosion driven piracy. Relatively level asymmetrically sloped ridges allow for the drainage divide across the ridge to retreat from headward erosion, but hindered when the ridge's apex undulates or when symmetrically sloped. Although these physical models cannot strictly simulate natural transverse drainages, the observed processes, their development over time, and resultant landforms roughly emulate their natural counterparts. Proposed originally from

  6. A Structural Equation Model of Expertise in College Physics

    ERIC Educational Resources Information Center

    Taasoobshirazi, Gita; Carr, Martha

    2009-01-01

    A model of expertise in physics was tested on a sample of 374 college students in 2 different level physics courses. Structural equation modeling was used to test hypothesized relationships among variables linked to expert performance in physics including strategy use, pictorial representation, categorization skills, and motivation, and these…

  7. Models for Curriculum and Pedagogy in Elementary School Physical Education

    ERIC Educational Resources Information Center

    Kulinna, Pamela Hodges

    2008-01-01

    The purpose of this article is to review current models for curriculum and pedagogy used in elementary school physical education programs. Historically, physical educators have developed and used a multiactivity curriculum in order to educate students through physical movement. More recently, a variety of alternative curricular models have been…

  8. A Structural Equation Model of Conceptual Change in Physics

    ERIC Educational Resources Information Center

    Taasoobshirazi, Gita; Sinatra, Gale M.

    2011-01-01

    A model of conceptual change in physics was tested on introductory-level, college physics students. Structural equation modeling was used to test hypothesized relationships among variables linked to conceptual change in physics including an approach goal orientation, need for cognition, motivation, and course grade. Conceptual change in physics…

  9. Investigation of the kinetic model equations

    NASA Astrophysics Data System (ADS)

    Liu, Sha; Zhong, Chengwen

    2014-03-01

    Currently the Boltzmann equation and its model equations are widely used in numerical predictions for dilute gas flows. The nonlinear integro-differential Boltzmann equation is the fundamental equation in the kinetic theory of dilute monatomic gases. By replacing the nonlinear fivefold collision integral term by a nonlinear relaxation term, its model equations such as the famous Bhatnagar-Gross-Krook (BGK) equation are mathematically simple. Since the computational cost of solving model equations is much less than that of solving the full Boltzmann equation, the model equations are widely used in predicting rarefied flows, multiphase flows, chemical flows, and turbulent flows although their predictions are only qualitatively right for highly nonequilibrium flows in transitional regime. In this paper the differences between the Boltzmann equation and its model equations are investigated aiming at giving guidelines for the further development of kinetic models. By comparing the Boltzmann equation and its model equations using test cases with different nonequilibrium types, two factors (the information held by nonequilibrium moments and the different relaxation rates of high- and low-speed molecules) are found useful for adjusting the behaviors of modeled collision terms in kinetic regime. The usefulness of these two factors are confirmed by a generalized model collision term derived from a mathematical relation between the Boltzmann equation and BGK equation that is also derived in this paper. After the analysis of the difference between the Boltzmann equation and the BGK equation, an attempt at approximating the collision term is proposed.

  10. Nuclear spin physics in quantum dots: An optical investigation

    NASA Astrophysics Data System (ADS)

    Urbaszek, Bernhard; Marie, Xavier; Amand, Thierry; Krebs, Olivier; Voisin, Paul; Maletinsky, Patrick; Högele, Alexander; Imamoglu, Atac

    2013-01-01

    The mesoscopic spin system formed by the 104-106 nuclear spins in a semiconductor quantum dot offers a unique setting for the study of many-body spin physics in the condensed matter. The dynamics of this system and its coupling to electron spins is fundamentally different from its bulk counterpart or the case of individual atoms due to increased fluctuations that result from reduced dimensions. In recent years, the interest in studying quantum-dot nuclear spin systems and their coupling to confined electron spins has been further fueled by its importance for possible quantum information processing applications. The fascinating nonlinear (quantum) dynamics of the coupled electron-nuclear spin system is universal in quantum dot optics and transport. In this article, experimental work performed over the last decade in studying this mesoscopic, coupled electron-nuclear spin system is reviewed. Here a special focus is on how optical addressing of electron spins can be exploited to manipulate and read out the quantum-dot nuclei. Particularly exciting recent developments in applying optical techniques to efficiently establish nonzero mean nuclear spin polarizations and using them to reduce intrinsic nuclear spin fluctuations are discussed. Both results critically influence the preservation of electron-spin coherence in quantum dots. This overall recently gained understanding of the quantum-dot nuclear spin system could enable exciting new research avenues such as experimental observations of spontaneous spin ordering or nonclassical behavior of the nuclear spin bath.

  11. Investigation of Self-Oscillation using Particle Balance Model

    NASA Astrophysics Data System (ADS)

    Bae, Inshik; Na, Byungkeun; Chang, Hongyoung

    2015-09-01

    Self-oscillation, which is obtained by using a DC-only power supply with specific anode voltage conditions, is investigated in a cylindrical system with thermal electrons using tungsten filaments. From analysis of the obtained oscillation profiles, the experimental data is consistent with the model derived from the particle balance model. The self-oscillation period characteristics with respect to the pressure and gas species are also analyzed. As the physics and particle motion of self-oscillation near the electron avalanche is analyzed in different perspective, this study may advance the understanding of this phenomenon. This research was supported by the Ministry of Knowledge Economy (MKE) of Korea (Grant No. 10041681).

  12. Investigation of self-oscillation using particle balance model

    SciTech Connect

    Bae, Inshik; Na, Byungkeun Chang, Hongyoung

    2015-08-15

    Self-oscillation obtained using a DC-only power supply under specific anode voltage conditions is investigated in a cylindrical system with thermal electrons using tungsten filaments. Analysis of the obtained oscillation profiles reveals that the experimental data are consistent with a model derived from the particle balance model. The self-oscillation period characteristics with respect to the pressure and gas species are also analyzed. As the physics and particle motion of self-oscillation near the plasma transition region are analyzed from different perspectives, this paper may advance the study of this phenomenon.

  13. Repassivation Investigations on Aluminium: Physical Chemistry of the Passive State

    NASA Astrophysics Data System (ADS)

    Nagy, Tristan Oliver; Weimerskirch, Morris Jhängi Joseph; Pacher, Ulrich; Kautek, Wolfgang

    2016-09-01

    We show the temporal change in repassivation mechanism as a time-dependent linear combination of a high-field model of oxide growth (HFM) and the point defect model (PDM). The observed switch in transient repassivation current-decrease under potentiostatic control occurs independently of the active electrode size and effective repassivation time for all applied overpotentials. For that, in situ depassivation of plasma electrolytically oxidized (PEO) coatings on aluminium was performed with nanosecond laser pulses at 266 nm and the repassivation current transients were recorded as a function of pulse number. A mathematical model combines the well established theories of oxide-film formation and growth kinetics, giving insight in the non linear transient behaviour of micro-defect passivation. According to our findings, the repassivation process can be described as a charge consumption via two concurrent channels. While the major current-decay at the very beginning of the fast healing oxide follows a point-defect type exponential damping, the HFM mechanism supersedes gradually, the longer the repassivation evolves. Furthermore, the material seems to reminisce former laser treatments via defects built-in during depassivation, leading to a higher charge contribution of the PDM mechanism at higher pulse numbers.

  14. Evolution and physics in comparative protein structure modeling.

    PubMed

    Fiser, András; Feig, Michael; Brooks, Charles L; Sali, Andrej

    2002-06-01

    From a physical perspective, the native structure of a protein is a consequence of physical forces acting on the protein and solvent atoms during the folding process. From a biological perspective, the native structure of proteins is a result of evolution over millions of years. Correspondingly, there are two types of protein structure prediction methods, de novo prediction and comparative modeling. We review comparative protein structure modeling and discuss the incorporation of physical considerations into the modeling process. A good starting point for achieving this aim is provided by comparative modeling by satisfaction of spatial restraints. Incorporation of physical considerations is illustrated by an inclusion of solvation effects into the modeling of loops.

  15. Physics of the inner heliosphere: Mechanisms, models and observational signatures

    NASA Technical Reports Server (NTRS)

    Withbroe, George L.

    1987-01-01

    Selected problems concerned with the important physical processes that occur in the corona and solar wind acceleration region, particularly time dependent phenomena were studied. Both the physics of the phenomena and the resultant effects on observational signatures, particularly spectroscopic signatures were also studied. Phenomena under study include: wave motions, particularly Alfven and fast mode waves; the formation of standing shocks in the inner heliosphere as a result of momentum and/or heat addition to the wind; and coronal transient phenomena where momentum and/or heat are deposited in the corona to produce transient plasma heating and/or mass ejection. The development of theoretical models for the inner heliosphere, the theoretical investigation of spectroscopic plasma diagnostics for this region, and the analysis of existing skylab and other relevant data are also included.

  16. Investigation and Modeling of Cranberry Weather Stress.

    NASA Astrophysics Data System (ADS)

    Croft, Paul Joseph

    Cranberry bog weather conditions and weather-related stress were investigated for development of crop yield prediction models and models to predict daily weather conditions in the bog. Field investigations and data gathering were completed at the Rutgers University Blueberry/Cranberry Research Center experimental bogs in Chatsworth, New Jersey. Study indicated that although cranberries generally exhibit little or no stomatal response to changing atmospheric conditions, the evaluation of weather-related stress could be accomplished via use of micrometeorological data. Definition of weather -related stress was made by establishing critical thresholds of the frequencies of occurrence, and magnitudes of, temperature and precipitation in the bog based on values determined by a review of the literature and a grower questionnaire. Stress frequencies were correlated with cranberry yield to develop predictive models based on the previous season's yield, prior season data, prior and current season data, current season data; and prior and current season data through July 31 of the current season. The predictive ability of the prior season models was best and could be used in crop planning and production. Further examination of bog micrometeorological data permitted the isolation of those weather conditions conducive to cranberry scald and allowed for the institution of a pilot scald advisory program during the 1991 season. The micrometeorological data from the bog was also used to develop models to predict daily canopy temperature and precipitation, based on upper air data, for grower use. Models were developed for each month for maximum and minimum temperatures and for precipitation and generally performed well. The modeling of bog weather conditions is an important first step toward daily prediction of cranberry weather-related stress.

  17. Investigating the physical basis of biomineralization. Final report

    SciTech Connect

    Dove, Patricia M.

    2001-01-01

    During the three years of this project, Professor Dove's laboratory made tremendous progress in understanding fundamental controls on crystal growth in simple model systems for the complex phenomenon of biological mineralization. Our collaboration with J.J. DeYoreo was productive and we surpassed the goals set forth in the original proposal to establish a new quantitative understanding of carbonate mineral crystallization. The findings from this project have been widely recognized across the scientific community by the award of the Mineralogical Society of America best paper award in 1998 and the Best University Research Award of 1999 at the Basic Energy sciences, Division of Geosciences ''Interfacial Processes Symposium''. In addition, two students working on this project received six different awards for their research findings.

  18. A simple physical model for deep moonquake occurrence times

    USGS Publications Warehouse

    Weber, R.C.; Bills, B.G.; Johnson, C.L.

    2010-01-01

    The physical process that results in moonquakes is not yet fully understood. The periodic occurrence times of events from individual clusters are clearly related to tidal stress, but also exhibit departures from the temporal regularity this relationship would seem to imply. Even simplified models that capture some of the relevant physics require a large number of variables. However, a single, easily accessible variable - the time interval I(n) between events - can be used to reveal behavior not readily observed using typical periodicity analyses (e.g., Fourier analyses). The delay-coordinate (DC) map, a particularly revealing way to display data from a time series, is a map of successive intervals: I(n+. 1) plotted vs. I(n). We use a DC approach to characterize the dynamics of moonquake occurrence. Moonquake-like DC maps can be reproduced by combining sequences of synthetic events that occur with variable probability at tidal periods. Though this model gives a good description of what happens, it has little physical content, thus providing only little insight into why moonquakes occur. We investigate a more mechanistic model. In this study, we present a series of simple models of deep moonquake occurrence, with consideration of both tidal stress and stress drop during events. We first examine the behavior of inter-event times in a delay-coordinate context, and then examine the output, in that context, of a sequence of simple models of tidal forcing and stress relief. We find, as might be expected, that the stress relieved by moonquakes influences their occurrence times. Our models may also provide an explanation for the opposite-polarity events observed at some clusters. ?? 2010.

  19. ATOMIC AND MOLECULAR PHYSICS: Modelling of a DNA packaging motor

    NASA Astrophysics Data System (ADS)

    Qian, Jun; Xie, Ping; Xue, Xiao-Guang; Wang, Peng-Ye

    2009-11-01

    During the assembly of many viruses, a powerful molecular motor packages the genome into a preassembled capsid. The Bacillus subtilis phage phi29 is an excellent model system to investigate the DNA packaging mechanism because of its highly efficient in vitro DNA packaging activity and the development of a single-molecule packaging assay. Here we make use of structural and biochemical experimental data to build a physical model of DNA packaging by the phi29 DNA packaging motor. Based on the model, various dynamic behaviours such as the packaging rate, pause frequency and slip frequency under different ATP concentrations, ADP concentrations, external loads as well as capsid fillings are studied by using Monte Carlo simulation. Good agreement is obtained between the simulated and available experimental results. Moreover, we make testable predictions that should guide future experiments related to motor function.

  20. Engaging Students In Modeling Instruction for Introductory Physics

    NASA Astrophysics Data System (ADS)

    Brewe, Eric

    2016-05-01

    Teaching introductory physics is arguably one of the most important things that a physics department does. It is the primary way that students from other science disciplines engage with physics and it is the introduction to physics for majors. Modeling instruction is an active learning strategy for introductory physics built on the premise that science proceeds through the iterative process of model construction, development, deployment, and revision. We describe the role that participating in authentic modeling has in learning and then explore how students engage in this process in the classroom. In this presentation, we provide a theoretical background on models and modeling and describe how these theoretical elements are enacted in the introductory university physics classroom. We provide both quantitative and video data to link the development of a conceptual model to the design of the learning environment and to student outcomes. This work is supported in part by DUE #1140706.

  1. Modelling Mathematical Reasoning in Physics Education

    ERIC Educational Resources Information Center

    Uhden, Olaf; Karam, Ricardo; Pietrocola, Mauricio; Pospiech, Gesche

    2012-01-01

    Many findings from research as well as reports from teachers describe students' problem solving strategies as manipulation of formulas by rote. The resulting dissatisfaction with quantitative physical textbook problems seems to influence the attitude towards the role of mathematics in physics education in general. Mathematics is often seen as a…

  2. We need more empirical investigations and model validation for a better understanding of crime. Comment on "Statistical physics of crime: A review" by M.R. D'Orsogna and M. Perc

    NASA Astrophysics Data System (ADS)

    Ribeiro, Haroldo V.

    2015-03-01

    Since the seminal works of Wilson and Kelling [1] in 1982, the "broken windows theory" seems to have been widely accepted among the criminologists and, in fact, empirical findings actually point out that criminals tend to return to previously visited locations. Crime has always been part of the urban society's agenda and has also attracted the attention of scholars from social sciences ever since. Furthermore, over the past six decades the world has experienced a quick and notorious urbanization process: by the eighties the urban population was about 40% of total population, and today more than half (54%) of the world population is urban [2]. The urbanization has brought us many benefits such as better working opportunities and health care, but has also created several problems such as pollution and a considerable rise in the criminal activities. In this context of urban problems, crime deserves a special attention because there is a huge necessity of empirical and mathematical (modeling) investigations which, apart from the natural academic interest, may find direct implications for the organization of our society by improving political decisions and resource allocation.

  3. Teacher Fidelity to One Physical Education Curricular Model

    ERIC Educational Resources Information Center

    Kloeppel, Tiffany; Kulinna, Pamela Hodges; Stylianou, Michalis; van der Mars, Hans

    2013-01-01

    This study addressed teachers' fidelity to one Physical Education curricular model. The theoretical framework guiding this study included professional development and fidelity to curricular models. In this study, teachers' fidelity to the Dynamic Physical Education (DPE) curricular model was measured for high and nonsupport district groups.…

  4. Experimental investigations in particle physics at intermediate energies

    SciTech Connect

    Auerbach, L.B.; Highland, V.L.; Martoff, C.J.; McFarlane, K.W.; Guss, C.; Kettell, S.

    1991-09-30

    The major elements of this project continues to be on fundamental symmetries and parameters of the Standard Model. The projects in the current period have been BNL E791 (a search for the decay K{sub L}{sup 0} {yields} {mu}e, which would violate the rule of separate lepton number conservation), test of an upgrade proposal (E871), and LSND, a neutrino experiment at LAMPF. For E791, data taking was completed in June 1990, and preliminary results are now available for the decays K{sub L}{sup 0} {yields} {mu}e and K{sub L}{sup 0} {yields} {mu}{mu}from the entire data set. The data for decay K{sub L}{sup 0} {yields} ee are still being analysed. These are an upper limit for the branching fraction for K{sub L}{sup 0} {yields} {mu}e of 3.5 {times} 10{sup {minus}11} (90% C.L.). From the 1990 data alone, we have a new (preliminary) value of the branching fraction for K{sub L}{sup 0} {yields} {mu}{mu} of (6.96{plus minus}0. 4{plus minus}0.22) {times} 10{sup {minus}9}, with a sample of 349 events. Combining this with earlier data gives (6.96{plus minus}0.34) {times} 10{sup 9}, by far the most precise value. The limit on the decay K{sub L}{sup 0} {yields} {mu}e places a lower limit on the mass of a new particle mediating such decays of 85 TeV. The LSND (Large Scintillator Neutrino Detector), a search for neutrino oscillations at LAMPF, has been approved, and is now underway. Other neutrino work at Los Alamos, E764, has resulted in a final publication. This includes the best, measurement of {nu}-nuclear scattering, in {nu}{sub mu} {sup 12}C inclusive cross sections. The measurement of the cross section for the exclusive reaction {nu}{sup mu}{sup 12}C {yields} {mu}{sup {minus}12} N is unique. In a new development, Dr. Martoff has established a facility for fabrication of superconducting detectors of nuclear radiation; the equipment has been funded and is partly installed. Planned uses include scattering for Dark Matter.' In summary, the objectives for this year have been met.

  5. Physical and Numerical Modeling of Buoyant Groundwater Plumes

    NASA Astrophysics Data System (ADS)

    Brakefield, L. K.; Abarca, E.; Langevin, C. D.; Clement, T. P.

    2007-12-01

    In coastal states, the injection of treated wastewater into deep saline aquifers offers a disposal alternative to ocean outfalls and discharge directly into local waterways. The density of treated wastewater is similar to that of freshwater but is often much lower than the ambient density of deep aquifers. This significant density contrast can cause upward buoyant movement of the wastewater plume during and after injection. Since some wastewater treatment plants inject more than 100 MGD of this treated wastewater, it is of the utmost importance to be able to not only determine the fate and transport rates of the plume, but to be able to best determine locations for monitoring wells for early detection of possible problems. In this study, both physical and numerical modeling were undertaken to investigate and understand buoyant plume behavior and transport. Physical models using a 2D cross-sectional Plexiglas tank filled with glass beads were carried out under different ambient density scenarios. The experiments consisted of injection of a freshwater pulse-source bubble into a fully saline tank. The injection occurred in an initially static system with no ambient flow. In the scenarios, the freshwater plume migrated vertically upward until reaching the top of the tank. Fingers developed because of the heterogeneity of the density dependent flow field. The vertical velocities and transport patterns of these plumes were compared to one another to investigate variances due to different ambient water densities. Using the finite-difference numerical code SEAWAT to simulate variable density flow, the experiments were numerically modeled and compared with the physical model results. Due to the sensitivity of this problem to numerical resolution, results from three different grids were compared to determine a reasonable compromise between computer runtimes and numerical accuracy. Furthermore, a comparison of advection solvers was undertaken to identify the best solver to

  6. Modelling surface water flood risk using coupled numerical and physical modelling techniques

    NASA Astrophysics Data System (ADS)

    Green, D. L.; Pattison, I.; Yu, D.

    2015-12-01

    Surface water (pluvial) flooding occurs due to intense precipitation events where rainfall cannot infiltrate into the sub-surface or drain via storm water systems. The perceived risk appears to have increased in recent years with pluvial flood events seeming more severe and frequent within the UK. Surface water flood risk currently accounts for one third of all UK flood risk, with approximately two million people living in urban areas being at risk of a 1 in 200 year flood event. Surface water flooding research often focuses upon using 1D, 2D or 1D-2D coupled numerical modelling techniques to understand the extent, depth and severity of actual or hypothetical flood scenarios. Although much research has been conducted using numerical modelling, field data available for model calibration and validation is limited due to the complexities associated with data collection in surface water flood conditions. Ultimately, the data which numerical models are based upon is often erroneous and inconclusive. Physical models offer an alternative and innovative environment to collect data within. A controlled, closed system allows independent variables to be altered individually to investigate cause and effect relationships. Despite this, physical modelling approaches are seldom used in surface water flooding research. Scaled laboratory experiments using a 9m2, two-tiered physical model consisting of: (i) a mist nozzle type rainfall simulator able to simulate a range of rainfall intensities similar to those observed within the United Kingdom, and; (ii) a fully interchangeable, scaled plot surface have been conducted to investigate and quantify the influence of factors such as slope, impermeability, building density/configuration and storm dynamics on overland flow and rainfall-runoff patterns within a range of terrestrial surface conditions. Results obtained within the physical modelling environment will be compared with numerical modelling results using FloodMap (Yu & Lane, 2006

  7. Intentional Development: A Model to Guide Lifelong Physical Activity

    ERIC Educational Resources Information Center

    Cherubini, Jeffrey M.

    2009-01-01

    Framed in the context of researching influences on physical activity and actually working with individuals and groups seeking to initiate, increase or maintain physical activity, the purpose of this review is to present the model of Intentional Development as a multi-theoretical approach to guide research and applied work in physical activity.…

  8. High school students' scientific epistemological beliefs, self-efficacy in learning physics and attitudes toward physics: a structural equation model

    NASA Astrophysics Data System (ADS)

    Kapucu, Serkan; Bahçivan, Eralp

    2015-05-01

    Background: There are some theoretical evidences that explain the relationships between core beliefs (i.e., epistemological beliefs) and peripheral beliefs (self-efficacy in learning) in the literature. The close relationships of such type of beliefs with attitudes are also discussed by some researchers. Constructing a model that investigates these relationships by considering theoretical and empirical evidences can empower researchers to discuss these relationships more comprehensively. Purpose: The purpose of this study is to explore the relationships among Turkish high school students' scientific epistemological beliefs, self-efficacy in learning physics and their attitudes toward physics. Sample: A total of 632 high school students participated in this study; however, 269 female and 229 male (a total of 498) high school students' data were used. Design and methods: Three distinct instruments that measure scientific epistemological beliefs, self-efficacy in learning physics and attitudes toward physics were combined into a unique questionnaire form and it was distributed to high school students. To explore the relationships among these variables, structural equation modeling was used. Results: The results showed that scientific epistemological belief dimensions uncovered by the nature of knowing (source and justification) significantly and positively related to both self-efficacy in learning physics and attitudes toward other important physics dimensions. Additionally, self-efficacy in learning physics significantly and positively predicted attitudes toward multiple physics dimensions (importance, comprehension and requirement). However, epistemological belief dimensions related to the nature of knowledge (certainty and development) did not have significant impact on self-efficacy in learning physics or attitudes toward physics. Conclusions: This study concludes that there are positive and significant relationships among Turkish high school students' scientific

  9. Animal models for investigating chronic pancreatitis

    PubMed Central

    2011-01-01

    Chronic pancreatitis is defined as a continuous or recurrent inflammatory disease of the pancreas characterized by progressive and irreversible morphological changes. It typically causes pain and permanent impairment of pancreatic function. In chronic pancreatitis areas of focal necrosis are followed by perilobular and intralobular fibrosis of the parenchyma, by stone formation in the pancreatic duct, calcifications in the parenchyma as well as the formation of pseudocysts. Late in the course of the disease a progressive loss of endocrine and exocrine function occurs. Despite advances in understanding the pathogenesis no causal treatment for chronic pancreatitis is presently available. Thus, there is a need for well characterized animal models for further investigations that allow translation to the human situation. This review summarizes existing experimental models and distinguishes them according to the type of pathological stimulus used for induction of pancreatitis. There is a special focus on pancreatic duct ligation, repetitive overstimulation with caerulein and chronic alcohol feeding. Secondly, attention is drawn to genetic models that have recently been generated and which mimic features of chronic pancreatitis in man. Each technique will be supplemented with data on the pathophysiological background of the model and their limitations will be discussed. PMID:22133269

  10. ConMap: Investigating new computer-based approaches to assessing conceptual knowledge structure in physics

    NASA Astrophysics Data System (ADS)

    Beatty, Ian D.

    2000-06-01

    There is a growing consensus among educational researchers that traditional problem-based assessments are not effective tools for diagnosing a student's knowledge state and for guiding pedagogical intervention, and that new tools grounded in the results of cognitive science research are needed. The ConMap (``Conceptual Mapping'') project, described in this dissertation, proposed and investigated some novel methods for assessing the conceptual knowledge structure of physics students. A set of brief computer-administered tasks for eliciting students' conceptual associations was designed. The basic approach of the tasks was to elicit spontaneous term associations from subjects by presenting them with a prompt term, or problem, or topic area, and having them type a set of response terms. Each response was recorded along with the time spent thinking of and typing it. Several studies were conducted in which data was collected on introductory physics students' performance on the tasks. A detailed statistical description of the data was compiled. Phenomenological characterization of the data (description and statistical summary of observed patterns) provided insight into the way students respond to the tasks, and discovered some notable features to guide modeling efforts. Possible correlations were investigated, some among different aspects of the ConMap data, others between aspects of the data and students' in-course exam scores. Several correlations were found which suggest that the ConMap tasks can successfully reveal information about students' knowledge structuring and level of expertise. Similarity was observed between data from one of the tasks and results from a traditional concept map task. Two rudimentary quantitative models for the temporal aspects of student performance on one of the tasks were constructed, one based on random probability distributions and the other on a detailed deterministic representation of conceptual knowledge structure. Both models were

  11. Investigating accident causation through information network modelling.

    PubMed

    Griffin, T G C; Young, M S; Stanton, N A

    2010-02-01

    Management of risk in complex domains such as aviation relies heavily on post-event investigations, requiring complex approaches to fully understand the integration of multi-causal, multi-agent and multi-linear accident sequences. The Event Analysis of Systemic Teamwork methodology (EAST; Stanton et al. 2008) offers such an approach based on network models. In this paper, we apply EAST to a well-known aviation accident case study, highlighting communication between agents as a central theme and investigating the potential for finding agents who were key to the accident. Ultimately, this work aims to develop a new model based on distributed situation awareness (DSA) to demonstrate that the risk inherent in a complex system is dependent on the information flowing within it. By identifying key agents and information elements, we can propose proactive design strategies to optimize the flow of information and help work towards avoiding aviation accidents. Statement of Relevance: This paper introduces a novel application of an holistic methodology for understanding aviation accidents. Furthermore, it introduces an ongoing project developing a nonlinear and prospective method that centralises distributed situation awareness and communication as themes. The relevance of findings are discussed in the context of current ergonomic and aviation issues of design, training and human-system interaction. PMID:20099174

  12. The Effect of Modeling and Visualization Resources on Student Understanding of Physical Hydrology

    ERIC Educational Resources Information Center

    Marshall, Jilll A.; Castillo, Adam J.; Cardenas, M. Bayani

    2015-01-01

    We investigated the effect of modeling and visualization resources on upper-division, undergraduate and graduate students' performance on an open-ended assessment of their understanding of physical hydrology. The students were enrolled in one of five sections of a physical hydrology course. In two of the sections, students completed homework…

  13. SHERLOCK: A quasi-model-independent new physics search strategy.

    NASA Astrophysics Data System (ADS)

    Knuteson, Bruce

    2000-04-01

    We develop a quasi-model-independent prescription for searching for physics responsible for the electroweak symmetry breaking in the Standard Model, and show a preliminary version of what we find when this prescription is applied to the DZero data.

  14. TOWARD EFFICIENT RIPARIAN RESTORATION: INTEGRATING ECONOMIC, PHYSICAL, AND BIOLOGICAL MODELS

    EPA Science Inventory

    This paper integrates economic, biological, and physical models to determine the efficient combination and spatial allocation of conservation efforts for water quality protection and salmonid habitat enhancement in the Grande Ronde basin, Oregon. The integrated modeling system co...

  15. An Empirical Investigation of the Dimensionality of the Physical Literacy Environment in Early Childhood Classrooms

    ERIC Educational Resources Information Center

    Dynia, Jaclyn M.; Schachter, Rachel E.; Piasta, Shayne B.; Justice, Laura M.; O'Connell, Ann A.; Yeager Pelatti, Christina

    2016-01-01

    This study investigated the dimensionality of the physical literacy environment of early childhood education classrooms. Data on the classroom physical literacy environment were collected from 245 classrooms using the Classroom Literacy Observation Profile. A combination of confirmatory and exploratory factor analysis was used to identify five…

  16. Investigation of Global Citizenship Levels of Pre-Service Physical Education Teachers

    ERIC Educational Resources Information Center

    Kayisoglu, Numan Bahadir

    2016-01-01

    The purpose of the present research is to define global citizenship levels of pre-service physical education teachers and investigate whether their global citizenship levels vary by various variables. A total of 485 pre-service teachers, studying at 3rd and 4th grades of undergraduate programs of physical education teaching at thirteen different…

  17. Investigation of a Chaotic Double Pendulum in the Basic Level Physics Teaching Laboratory

    ERIC Educational Resources Information Center

    Vanko, Peter

    2007-01-01

    First-year physics students at the Technical University of Budapest carry out a wide range of measurements in the Basic Level Physics Teaching Laboratory. One of the most exciting experiments is the investigation of a chaotic double pendulum by a V-scope, a powerful three-dimensional motion tracking system. After a brief introduction to the…

  18. Investigation of the Perceived Causes of Pre-Service Physics Teachers' Problems Encountered in School Experience

    ERIC Educational Resources Information Center

    Körhasan, Nilüfer Didis; Didis, M. Gözde

    2015-01-01

    This study investigates a group of pre-service physics teachers' perceptions about the causes of problems in school experience through the attribution theory. The participants were thirteen pre-service physics teachers from a public university in Turkey. Data were collected through the interviews by requesting the participants to reflect their own…

  19. Investigating the Reciprocal Nature of Service-Learning in Physical Education Teacher Education

    ERIC Educational Resources Information Center

    Galvan, Christine; Parker, Melissa

    2011-01-01

    Constructivism theory (Crotty, 1998) served as the framework to investigate the reciprocal nature of a service-learning project that involved physical education pre-service teachers and urban underserved youth. Participants included three physical education teacher education (PETE) candidates and 15 youth between the ages of 6 and 13 who were…

  20. An Empirical-Mathematical Modelling Approach to Upper Secondary Physics

    ERIC Educational Resources Information Center

    Angell, Carl; Kind, Per Morten; Henriksen, Ellen K.; Guttersrud, Oystein

    2008-01-01

    In this paper we describe a teaching approach focusing on modelling in physics, emphasizing scientific reasoning based on empirical data and using the notion of multiple representations of physical phenomena as a framework. We describe modelling activities from a project (PHYS 21) and relate some experiences from implementation of the modelling…

  1. Assessing the Integration of Computational Modeling and ASU Modeling Instruction in the High School Physics Classroom

    NASA Astrophysics Data System (ADS)

    Aiken, John; Schatz, Michael; Burk, John; Caballero, Marcos; Thoms, Brian

    2012-03-01

    We describe the assessment of computational modeling in a ninth grade classroom in the context of the Arizona Modeling Instruction physics curriculum. Using a high-level programming environment (VPython), students develop computational models to predict the motion of objects under a variety of physical situations (e.g., constant net force), to simulate real world phenomenon (e.g., car crash), and to visualize abstract quantities (e.g., acceleration). The impact of teaching computation is evaluated through a proctored assignment that asks the students to complete a provided program to represent the correct motion. Using questions isomorphic to the Force Concept Inventory we gauge students understanding of force in relation to the simulation. The students are given an open ended essay question that asks them to explain the steps they would use to model a physical situation. We also investigate the attitudes and prior experiences of each student using the Computation Modeling in Physics Attitudinal Student Survey (COMPASS) developed at Georgia Tech as well as a prior computational experiences survey.

  2. Apnoeic oxygenation in pregnancy: a modelling investigation.

    PubMed

    Pillai, A; Chikhani, M; Hardman, J G

    2016-09-01

    Recent studies have shown that nasal oxygen delivery can prolong the time to desaturation during apnoea in the non-pregnant population. We investigated the benefits of apnoeic oxygenation during rapid sequence induction in the obstetric population using computational modelling. We used the Nottingham Physiology Simulator, and pre-oxygenated seven models of pregnancy for 3 min using Fi O2 1.0, before inducing apnoea. We found that increasing Fi O2 at the open glottis increased the time to desaturation, extending the time taken for Sa O2 to reach 40% from 4.5 min to 58 min in the average parturient model (not in labour). Our study suggests that a small increase in time to desaturation could be achieved at Fi O2 0.4-0.6, which could be delivered by standard nasal cannulae. The greatest increases in time to desaturation were seen at Fi O2 1.0, which could be delivered by high-flow nasal cannulae under ideal conditions. PMID:27440389

  3. Using the Bifocal Modeling Framework to Resolve "Discrepant Events" between Physical Experiments and Virtual Models in Biology

    ERIC Educational Resources Information Center

    Blikstein, Paulo; Fuhrmann, Tamar; Salehi, Shima

    2016-01-01

    In this paper, we investigate an approach to supporting students' learning in science through a combination of physical experimentation and virtual modeling. We present a study that utilizes a scientific inquiry framework, which we call "bifocal modeling," to link student-designed experiments and computer models in real time. In this…

  4. Modeling the Discrimination Power of Physics Items

    ERIC Educational Resources Information Center

    Mesic, Vanes

    2011-01-01

    For the purposes of tailoring physics instruction in accordance with the needs and abilities of the students it is useful to explore the knowledge structure of students of different ability levels. In order to precisely differentiate the successive, characteristic states of student achievement it is necessary to use test items that possess…

  5. Investigating Students' Ideas About X-rays While Developing Teaching Materials for a Medical Physics Course

    SciTech Connect

    Kalita, Spartak; Zollman, Dean

    2007-01-30

    The goal of the Modern Miracle Medical Machines project is to promote pre-med students' interest in physics by using the context of contemporary medical imaging. The X-ray medical imaging learning module will be a central part of this effort. To investigate students' transfer of learning in this context we have conducted a series of clinical and teaching interviews. In the latter interview, some of the proposed learning materials were used. The students brought to our discussion pieces of knowledge transferred from very different sources such as their own X-ray experiences, previous learning and the mass media. This transfer seems to result in more or less firm mental models which often are not always internally consistent or coherent.

  6. An innovation in physical modelling for testing marine renewables technology

    NASA Astrophysics Data System (ADS)

    Todd, David; Whitehouse, Richard; Harris, John; Liddiard, Mark

    2015-04-01

    HR Wallingford has undertaken physical modelling of scour around structures since its creation as a government research laboratory in 1947. Since privatisation in 1982 HR Wallingford has carried out a large number of studies for offshore developments including renewable energy developments and offshore wind in particular, looking at scour around offshore foundations and cables. To maintain our position as both a research and consultancy organisation delivering high quality work we have developed a new purpose built physical modelling facility. The Fast Flow Facility is a dual-channel, race track shaped flume and the only large scale physical modelling facility of this kind offering wave, fast tidal current and recirculating sediment capabilities. The 75 m long, 8 m wide and 2.5 m deep Fast Flow Facility has two working channels of 4 m and 2.6 m width. Holding up to a million litres of water the facility can generate waves with significant wave heights, Hs, of up to 0.5 m and maximum wave heights of up to 1 m in combination with flows of up to 2 m/s (~4 knots). This state-of-the-art facility combines fast, reversible currents with wave generation and sediment transport modelling in a single flume, allowing us to further develop our understanding of sediment transport within the marine environment and keep us at the forefront of sediment transport research. The facility has been designed with the marine renewables sector in mind, with a 4 x 4 x 1m deep sediment pit in the centre of the flume allowing investigations to provide improved understanding of the detailed processes which lead to scour, and enabling improvements in prediction capabilities for marine scour in different sediment seabed compositions (non-cohesive and cohesive) for a range of structure types (monopiles, jackets, gravity base foundations, jack-ups etc.). The facility also enables the testing of scour protection methodologies at relatively large scale (typically 1: 10 - 1:20) and allows for

  7. Testing a Theoretical Model of Immigration Transition and Physical Activity.

    PubMed

    Chang, Sun Ju; Im, Eun-Ok

    2015-01-01

    The purposes of the study were to develop a theoretical model to explain the relationships between immigration transition and midlife women's physical activity and test the relationships among the major variables of the model. A theoretical model, which was developed based on transitions theory and the midlife women's attitudes toward physical activity theory, consists of 4 major variables, including length of stay in the United States, country of birth, level of acculturation, and midlife women's physical activity. To test the theoretical model, a secondary analysis with data from 127 Hispanic women and 123 non-Hispanic (NH) Asian women in a national Internet study was used. Among the major variables of the model, length of stay in the United States was negatively associated with physical activity in Hispanic women. Level of acculturation in NH Asian women was positively correlated with women's physical activity. Country of birth and level of acculturation were significant factors that influenced physical activity in both Hispanic and NH Asian women. The findings support the theoretical model that was developed to examine relationships between immigration transition and physical activity; it shows that immigration transition can play an essential role in influencing health behaviors of immigrant populations in the United States. The NH theoretical model can be widely used in nursing practice and research that focus on immigrant women and their health behaviors. Health care providers need to consider the influences of immigration transition to promote immigrant women's physical activity. PMID:26502554

  8. Testing a Theoretical Model of Immigration Transition and Physical Activity.

    PubMed

    Chang, Sun Ju; Im, Eun-Ok

    2015-01-01

    The purposes of the study were to develop a theoretical model to explain the relationships between immigration transition and midlife women's physical activity and test the relationships among the major variables of the model. A theoretical model, which was developed based on transitions theory and the midlife women's attitudes toward physical activity theory, consists of 4 major variables, including length of stay in the United States, country of birth, level of acculturation, and midlife women's physical activity. To test the theoretical model, a secondary analysis with data from 127 Hispanic women and 123 non-Hispanic (NH) Asian women in a national Internet study was used. Among the major variables of the model, length of stay in the United States was negatively associated with physical activity in Hispanic women. Level of acculturation in NH Asian women was positively correlated with women's physical activity. Country of birth and level of acculturation were significant factors that influenced physical activity in both Hispanic and NH Asian women. The findings support the theoretical model that was developed to examine relationships between immigration transition and physical activity; it shows that immigration transition can play an essential role in influencing health behaviors of immigrant populations in the United States. The NH theoretical model can be widely used in nursing practice and research that focus on immigrant women and their health behaviors. Health care providers need to consider the influences of immigration transition to promote immigrant women's physical activity.

  9. Simple universal models capture all classical spin physics.

    PubMed

    De las Cuevas, Gemma; Cubitt, Toby S

    2016-03-11

    Spin models are used in many studies of complex systems because they exhibit rich macroscopic behavior despite their microscopic simplicity. Here, we prove that all the physics of every classical spin model is reproduced in the low-energy sector of certain "universal models," with at most polynomial overhead. This holds for classical models with discrete or continuous degrees of freedom. We prove necessary and sufficient conditions for a spin model to be universal and show that one of the simplest and most widely studied spin models, the two-dimensional Ising model with fields, is universal. Our results may facilitate physical simulations of Hamiltonians with complex interactions.

  10. Numerical modelling for intense laser physics

    SciTech Connect

    Audit, Edouard; Schurtz, Guy

    2007-04-06

    The recent start-up of large intense laser facilities such as the Ligne d'Integration Laser (LIL) or the LULI2000 and the arrival in the near future of the Laser Megajoule (LMJ) gives a great perspective for laboratory astrophysics, dense matter studies and inertial fusion. To make the most of these opportunities, several teams have set up a program which aims at satisfying simulation needs in the fields of Astrophysics, Hot Dense Matter and Inertial Confinement Fusion. A large part of the scientific production in these fields relies upon simulations of complex unsteady hydro flows, coupled to non equilibrium transport and chemical kinetics. As the characteristic time scales of transport may be much shorter than the fluid time scale, implicit numerical methods are often required. Atomics physics data, and in particular equation of states and opacities, are a key and critical ingredients for the simulations done in stellar physics, laboratory astrophysics and in many other fields of astrophysics. We will show the different codes used in the various fields of the project and the different methods used to capture the desired physics. We will also present ODALISC, a new opacity database aiming at providing the community with spectral opacities and numerical tools to use them efficiently in radiation-hydrodynamics codes.

  11. A model-based view of physics for computational activities in the introductory physics course

    NASA Astrophysics Data System (ADS)

    Buffler, Andy; Pillay, Seshini; Lubben, Fred; Fearick, Roger

    2008-04-01

    A model-based view of physics provides a framework within which computational activities may be structured so as to present to students an authentic representation of physics as a discipline. The use of the framework in teaching computation at the introductory physics level is illustrated by a case study based on the simultaneous translation and rotation of a disk-shaped spaceship. Student responses to an interactive worksheet are used to support guidelines for the design of computational tasks to enhance the understanding of physical systems through numerical problem solving.

  12. Relativistic models in nuclear and particle physics

    SciTech Connect

    Coester, F.

    1988-01-01

    A comparative overview is presented of different approaches to the construction of phenomenological dynamical models that respect basic principles of quantum theory and relativity. Wave functions defined as matrix elements of products of field operators on one hand and wave functions that are defined as representatives of state vectors in model Hilbert spaces are related differently to observables and dynamical models for these wave functions have each distinct advantages and disadvantages 34 refs.

  13. Aspects of Particle Physics Beyond the Standard Model

    NASA Astrophysics Data System (ADS)

    Lu, Xiaochuan

    This dissertation describes a few aspects of particles beyond the Standard Model, with a focus on the remaining questions after the discovery of a Standard Model-like Higgs boson. In specific, three topics are discussed in sequence: neutrino mass and baryon asymmetry, naturalness problem of Higgs mass, and placing constraints on theoretical models from precision measurements. First, the consequence of the neutrino mass anarchy on cosmology is studied. Attentions are paid in particular to the total mass of neutrinos and baryon asymmetry through leptogenesis. With the assumption of independence among mass matrix entries in addition to the basis independence, Gaussian measure is the only choice. On top of Gaussian measure, a simple approximate U(1) flavor symmetry makes leptogenesis highly successful. Correlations between the baryon asymmetry and the light-neutrino quantities are investigated. Also discussed are possible implications of recently suggested large total mass of neutrinos by the SDSS/BOSS data. Second, the Higgs mass implies fine-tuning for minimal theories of weak-scale supersymmetry (SUSY). Non-decoupling effects can boost the Higgs mass when new states interact with the Higgs, but new sources of SUSY breaking that accompany such extensions threaten naturalness. I will show that two singlets with a Dirac mass can increase the Higgs mass while maintaining naturalness in the presence of large SUSY breaking in the singlet sector. The modified Higgs phenomenology of this scenario, termed "Dirac NMSSM", is also studied. Finally, the sensitivities of future precision measurements in probing physics beyond the Standard Model are studied. A practical three-step procedure is presented for using the Standard Model effective field theory (SM EFT) to connect ultraviolet (UV) models of new physics with weak scale precision observables. With this procedure, one can interpret precision measurements as constraints on the UV model concerned. A detailed explanation is

  14. Physic-Based Imaginary Potential and Incoherent Current Models for RTD Simulation Using Optical Model

    NASA Astrophysics Data System (ADS)

    Sharifi, M. J.; Navi, Keivan

    In this study, a physic-based model for calculating incoherent current of Resonant Tunneling Diode (RTD) has been introduced which is based on the meta-stable states of RTD. Also a physic-based model for imaginary potential is introduced which has full position, bias, energy and temperature dependency of the imaginary potential. By incorporating these two physic-based models, the conventional optical model becomes a completely physic-based approach to RTD.

  15. The Investigation of Physical Performance Status of Visually and Hearing Impaired Applying Judo Training Program

    ERIC Educational Resources Information Center

    Karakoc, Onder

    2016-01-01

    It was aimed to investigate the physical performances of visually and hearing impaired doing judo training in this study. 32 male athletes, who were doing judo training, volunteer and, visually and hearing impaired, participated in this study. The investigation was applied to visually impaired (N = 12, mean ± SD; age: 25.75 ± 3.55 years, height:…

  16. Investigating Allegations of Inappropriate Physical Punishment of Students by School Employees.

    ERIC Educational Resources Information Center

    Pearce, Alexis C.

    1992-01-01

    Any complaint against a school employee regarding inappropriate physical punishment should be taken seriously by administrators and pursued vigorously by an investigating attorney. The standards (especially regarding probable cause and obtaining warrants) for investigating such allegations are less stringent than those imposed in criminal…

  17. Investigation of the Reasons of Negative Perceptions of Undergraduate Students Regarding the Modern Physics Course

    ERIC Educational Resources Information Center

    Aksakalli, Ayhan; Salar, Riza; Turgut, Umit

    2016-01-01

    In this research, the negative perceptions of undergraduate students regarding modern physics course and the causes of their negative perceptions have been investigated. For this investigation, a qualitative and quantitative method (mix method) was chosen for data collection and analysis. The study group of the research consists of a total of 169…

  18. An Investigation into the Effectiveness of Problem-Based Learning in a Physical Chemistry Laboratory Course

    ERIC Educational Resources Information Center

    Gurses, Ahmet; Acikyildiz, Metin; Dogar, Cetin; Sozbilir, Mustafa

    2007-01-01

    The aim of this study was to investigate the effectiveness of a problem-based learning (PBL) approach in a physical chemistry laboratory course. The parameters investigated were students' attitudes towards a chemistry laboratory course, scientific process skills of students and their academic achievement. The design of the study was one group…

  19. Experimental investigation of a flapping wing model

    NASA Astrophysics Data System (ADS)

    Hubel, Tatjana Y.; Tropea, Cameron

    The main objective of this research study was to investigate the aerodynamic forces of an avian flapping wing model system. The model size and the flow conditions were chosen to approximate the flight of a goose. Direct force measurements, using a three-component balance, and PIV flow field measurements parallel and perpendicular to the oncoming flow, were performed in a wind tunnel at Reynolds numbers between 28,000 and 141,000 (3-15 m/s), throughout a range of reduced frequencies between 0.04 and 0.20. The appropriateness of quasi-steady assumptions used to compare 2D, time-averaged particle image velocimetry (PIV) measurements in the wake with direct force measurements was evaluated. The vertical force coefficient for flapping wings was typically significantly higher than the maximum coefficient of the fixed wing, implying the influence of unsteady effects, such as delayed stall, even at low reduced frequencies. This puts the validity of the quasi-steady assumption into question. The (local) change in circulation over the wing beat cycle and the circulation distribution along the wingspan were obtained from the measurements in the tip and transverse vortex planes. Flow separation could be observed in the distribution of the circulation, and while the circulation derived from the wake measurements failed to agree exactly with the absolute value of the circulation, the change in circulation over the wing beat cycle was in excellent agreement for low and moderate reduced frequencies. The comparison between the PIV measurements in the two perpendicular planes and the direct force balance measurements, show that within certain limitations the wake visualization is a powerful tool to gain insight into force generation and the flow behavior on flapping wings over the wing beat cycle.

  20. Experimental investigation of a flapping wing model

    NASA Astrophysics Data System (ADS)

    Hubel, Tatjana Y.; Tropea, Cameron

    2009-05-01

    The main objective of this research study was to investigate the aerodynamic forces of an avian flapping wing model system. The model size and the flow conditions were chosen to approximate the flight of a goose. Direct force measurements, using a three-component balance, and PIV flow field measurements parallel and perpendicular to the oncoming flow, were performed in a wind tunnel at Reynolds numbers between 28,000 and 141,000 (3-15 m/s), throughout a range of reduced frequencies between 0.04 and 0.20. The appropriateness of quasi-steady assumptions used to compare 2D, time-averaged particle image velocimetry (PIV) measurements in the wake with direct force measurements was evaluated. The vertical force coefficient for flapping wings was typically significantly higher than the maximum coefficient of the fixed wing, implying the influence of unsteady effects, such as delayed stall, even at low reduced frequencies. This puts the validity of the quasi-steady assumption into question. The (local) change in circulation over the wing beat cycle and the circulation distribution along the wingspan were obtained from the measurements in the tip and transverse vortex planes. Flow separation could be observed in the distribution of the circulation, and while the circulation derived from the wake measurements failed to agree exactly with the absolute value of the circulation, the change in circulation over the wing beat cycle was in excellent agreement for low and moderate reduced frequencies. The comparison between the PIV measurements in the two perpendicular planes and the direct force balance measurements, show that within certain limitations the wake visualization is a powerful tool to gain insight into force generation and the flow behavior on flapping wings over the wing beat cycle.

  1. Engineered Barrier System: Physical and Chemical Environment Model

    SciTech Connect

    D. M. Jolley; R. Jarek; P. Mariner

    2004-02-09

    The conceptual and predictive models documented in this Engineered Barrier System: Physical and Chemical Environment Model report describe the evolution of the physical and chemical conditions within the waste emplacement drifts of the repository. The modeling approaches and model output data will be used in the total system performance assessment (TSPA-LA) to assess the performance of the engineered barrier system and the waste form. These models evaluate the range of potential water compositions within the emplacement drifts, resulting from the interaction of introduced materials and minerals in dust with water seeping into the drifts and with aqueous solutions forming by deliquescence of dust (as influenced by atmospheric conditions), and from thermal-hydrological-chemical (THC) processes in the drift. These models also consider the uncertainty and variability in water chemistry inside the drift and the compositions of introduced materials within the drift. This report develops and documents a set of process- and abstraction-level models that constitute the engineered barrier system: physical and chemical environment model. Where possible, these models use information directly from other process model reports as input, which promotes integration among process models used for total system performance assessment. Specific tasks and activities of modeling the physical and chemical environment are included in the technical work plan ''Technical Work Plan for: In-Drift Geochemistry Modeling'' (BSC 2004 [DIRS 166519]). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system analysis model reports.

  2. Chewing simulation with a physically accurate deformable model.

    PubMed

    Pascale, Andra Maria; Ruge, Sebastian; Hauth, Steffen; Kordaß, Bernd; Linsen, Lars

    2015-01-01

    Nowadays, CAD/CAM software is being used to compute the optimal shape and position of a new tooth model meant for a patient. With this possible future application in mind, we present in this article an independent and stand-alone interactive application that simulates the human chewing process and the deformation it produces in the food substrate. Chewing motion sensors are used to produce an accurate representation of the jaw movement. The substrate is represented by a deformable elastic model based on the finite linear elements method, which preserves physical accuracy. Collision detection based on spatial partitioning is used to calculate the forces that are acting on the deformable model. Based on the calculated information, geometry elements are added to the scene to enhance the information available for the user. The goal of the simulation is to present a complete scene to the dentist, highlighting the points where the teeth came into contact with the substrate and giving information about how much force acted at these points, which therefore makes it possible to indicate whether the tooth is being used incorrectly in the mastication process. Real-time interactivity is desired and achieved within limits, depending on the complexity of the employed geometric models. The presented simulation is a first step towards the overall project goal of interactively optimizing tooth position and shape under the investigation of a virtual chewing process using real patient data (Fig 1). PMID:26389135

  3. Hidden sector DM models and Higgs physics

    SciTech Connect

    Ko, P.

    2014-06-24

    We present an extension of the standard model to dark sector with an unbroken local dark U(1){sub X} symmetry. Including various singlet portal interactions provided by the standard model Higgs, right-handed neutrinos and kinetic mixing, we show that the model can address most of phenomenological issues (inflation, neutrino mass and mixing, baryon number asymmetry, dark matter, direct/indirect dark matter searches, some scale scale puzzles of the standard collisionless cold dark matter, vacuum stability of the standard model Higgs potential, dark radiation) and be regarded as an alternative to the standard model. The Higgs signal strength is equal to one as in the standard model for unbroken U(1){sub X} case with a scalar dark matter, but it could be less than one independent of decay channels if the dark matter is a dark sector fermion or if U(1){sub X} is spontaneously broken, because of a mixing with a new neutral scalar boson in the models.

  4. Physical and Mathematical Modeling in Experimental Papers.

    PubMed

    Möbius, Wolfram; Laan, Liedewij

    2015-12-17

    An increasing number of publications include modeling. Often, such studies help us to gain a deeper insight into the phenomena studied and break down barriers between experimental and theoretical communities. However, combining experimental and theoretical work is challenging for authors, reviewers, and readers. To help maximize the usefulness and impact of combined theoretical and experimental research, this Primer describes the purpose, usefulness, and different types of models and addresses the practical aspect of integrated publications by outlining characteristics of good modeling, presentation, and fruitful collaborations.

  5. Physical and Mathematical Modeling in Experimental Papers.

    PubMed

    Möbius, Wolfram; Laan, Liedewij

    2015-12-17

    An increasing number of publications include modeling. Often, such studies help us to gain a deeper insight into the phenomena studied and break down barriers between experimental and theoretical communities. However, combining experimental and theoretical work is challenging for authors, reviewers, and readers. To help maximize the usefulness and impact of combined theoretical and experimental research, this Primer describes the purpose, usefulness, and different types of models and addresses the practical aspect of integrated publications by outlining characteristics of good modeling, presentation, and fruitful collaborations. PMID:26687351

  6. Educational Value and Models-Based Practice in Physical Education

    ERIC Educational Resources Information Center

    Kirk, David

    2013-01-01

    A models-based approach has been advocated as a means of overcoming the serious limitations of the traditional approach to physical education. One of the difficulties with this approach is that physical educators have sought to use it to achieve diverse and sometimes competing educational benefits, and these wide-ranging aspirations are rarely if…

  7. A Model of Physical Performance for Occupational Tasks.

    ERIC Educational Resources Information Center

    Hogan, Joyce

    This report acknowledges the problems faced by industrial/organizational psychologists who must make personnel decisions involving physically demanding jobs. The scarcity of criterion-related validation studies and the difficulty of generalizing validity are considered, and a model of physical performance that builds on Fleishman's (1984)…

  8. Early Childhood Educators' Experience of an Alternative Physical Education Model

    ERIC Educational Resources Information Center

    Tsangaridou, Niki; Genethliou, Nicholas

    2016-01-01

    Alternative instructional and curricular models are regarded as more comprehensive and suitable approaches to providing quality physical education (Kulinna 2008; Lund and Tannehill 2010; McKenzie and Kahan 2008; Metzler 2011; Quay and Peters 2008). The purpose of this study was to describe the impact of the Early Steps Physical Education…

  9. Physical models of giant subaqueous rock avalanches

    NASA Astrophysics Data System (ADS)

    De Blasio, F. V.

    2011-12-01

    Large subaqueous rock avalanches are characterized by horizontal run-outs approximately ten times longer than the fall height. It is shown that this mobility is somehow puzzling, as it corresponds to a decrease of the effective friction coefficient by a factor 10-50 compared to bare rock. Two dynamical models are so introduced to explain the observed mobility. In the first model, the fast-moving fragmented rock avalanche is subjected to a lift force that makes it hydroplane, avoiding contact with the sea floor. In a second model the fragmented material ingests water, transforming into a non-Newtonian fluid that progressively reduces its shear strength. Both models give peak velocity of 65-70 m/s, which implies a high potential for tsunami generation.

  10. Discrete mathematical physics and particle modeling

    NASA Astrophysics Data System (ADS)

    Greenspan, D.

    The theory and application of the arithmetic approach to the foundations of both Newtonian and special relativistic mechanics are explored. Using only arithmetic, a reformulation of the Newtonian approach is given for: gravity; particle modeling of solids, liquids, and gases; conservative modeling of laminar and turbulent fluid flow, heat conduction, and elastic vibration; and nonconservative modeling of heat convection, shock-wave generation, the liquid drop problem, porous flow, the interface motion of a melting solid, soap films, string vibrations, and solitons. An arithmetic reformulation of special relativistic mechanics is given for theory in one space dimension, relativistic harmonic oscillation, and theory in three space dimensions. A speculative quantum mechanical model of vibrations in the water molecule is also discussed.

  11. Massive Stars: Input Physics and Stellar Models

    NASA Astrophysics Data System (ADS)

    El Eid, M. F.; The, L.-S.; Meyer, B. S.

    2009-10-01

    We present a general overview of the structure and evolution of massive stars of masses ≥12 M ⊙ during their pre-supernova stages. We think it is worth reviewing this topic owing to the crucial role of massive stars in astrophysics, especially in the evolution of galaxies and the universe. We have performed several test computations with the aim to analyze and discuss many physical uncertainties still encountered in massive-star evolution. In particular, we explore the effects of mass loss, convection, rotation, 12C( α, γ)16O reaction and initial metallicity. We also compare and analyze the similarities and differences among various works and ours. Finally, we present useful comments on the nucleosynthesis from massive stars concerning the s-process and the yields for 26Al and 60Fe.

  12. A Physically Based Coupled Chemical and Physical Weathering Model for Simulating Soilscape Evolution

    NASA Astrophysics Data System (ADS)

    Willgoose, G. R.; Welivitiya, D.; Hancock, G. R.

    2015-12-01

    A critical missing link in existing landscape evolution models is a dynamic soil evolution models where soils co-evolve with the landform. Work by the authors over the last decade has demonstrated a computationally manageable model for soil profile evolution (soilscape evolution) based on physical weathering. For chemical weathering it is clear that full geochemistry models such as CrunchFlow and PHREEQC are too computationally intensive to be couplable to existing soilscape and landscape evolution models. This paper presents a simplification of CrunchFlow chemistry and physics that makes the task feasible, and generalises it for hillslope geomorphology applications. Results from this simplified model will be compared with field data for soil pedogenesis. Other researchers have previously proposed a number of very simple weathering functions (e.g. exponential, humped, reverse exponential) as conceptual models of the in-profile weathering process. The paper will show that all of these functions are possible for specific combinations of in-soil environmental, geochemical and geologic conditions, and the presentation will outline the key variables controlling which of these conceptual models can be realistic models of in-profile processes and under what conditions. The presentation will finish by discussing the coupling of this model with a physical weathering model, and will show sample results from our SSSPAM soilscape evolution model to illustrate the implications of including chemical weathering in the soilscape evolution model.

  13. Propulsion Physics Under the Changing Density Field Model

    NASA Technical Reports Server (NTRS)

    Robertson, Glen A.

    2011-01-01

    To grow as a space faring race, future spaceflight systems will requires new propulsion physics. Specifically a propulsion physics model that does not require mass ejection without limiting the high thrust necessary to accelerate within or beyond our solar system and return within a normal work period or lifetime. In 2004 Khoury and Weltman produced a density dependent cosmology theory they called Chameleon Cosmology, as at its nature, it is hidden within known physics. This theory represents a scalar field within and about an object, even in the vacuum. Whereby, these scalar fields can be viewed as vacuum energy fields with definable densities that permeate all matter; having implications to dark matter/energy with universe acceleration properties; implying a new force mechanism for propulsion physics. Using Chameleon Cosmology, the author has developed a new propulsion physics model, called the Changing Density Field (CDF) Model. This model relates to density changes in these density fields, where the density field density changes are related to the acceleration of matter within an object. These density changes in turn change how an object couples to the surrounding density fields. Whereby, thrust is achieved by causing a differential in the coupling to these density fields about an object. Since the model indicates that the density of the density field in an object can be changed by internal mass acceleration, even without exhausting mass, the CDF model implies a new propellant-less propulsion physics model

  14. Investigation of post hydraulic fracturing well cleanup physics in the Cana Woodford Shale

    NASA Astrophysics Data System (ADS)

    Lu, Rong

    Hydraulic fracturing was first carried out in the 1940s and has gained popularity in current development of unconventional resources. Flowing back the fracturing fluids is critical to a frac job, and determining well cleanup characteristics using the flowback data can help improve frac design. It has become increasingly important as a result of the unique flowback profiles observed in some shale gas plays due to the unconventional formation characteristics. Computer simulation is an efficient and effective way to tackle the problem. History matching can help reveal some mechanisms existent in the cleanup process. The Fracturing, Acidizing, Stimulation Technology (FAST) Consortium at Colorado School of Mines previously developed a numerical model for investigating the hydraulic fracturing process, cleanup, and relevant physics. It is a three-dimensional, gas-water, coupled fracture propagation-fluid flow simulator, which has the capability to handle commonly present damage mechanisms. The overall goal of this research effort is to validate the model on real data and to investigate the dominant physics in well cleanup for the Cana Field, which produces from the Woodford Shale in Oklahoma. To achieve this goal, first the early time delayed gas production was explained and modeled, and a simulation framework was established that included all three relevant damage mechanisms for a slickwater fractured well. Next, a series of sensitivity analysis of well cleanup to major reservoir, fracture, and operational variables was conducted; five of the Cana wells' initial flowback data were history matched, specifically the first thirty days' gas and water producing rates. Reservoir matrix permeability, net pressure, Young's modulus, and formation pressure gradient were found to have an impact on the gas producing curve's shape, in different ways. Some moderately good matches were achieved, with the outcome of some unknown reservoir information being proposed using the

  15. Investigating System Dependability Modeling Using AADL

    NASA Technical Reports Server (NTRS)

    Hall, Brendan; Driscoll, Kevin R.; Madl, Gabor

    2013-01-01

    This report describes Architecture Analysis & Design Language (AADL) models for a diverse set of fault-tolerant, embedded data networks and describes the methods and tools used to created these models. It also includes error models per the AADL Error Annex. Some networks were modeled using Error Detection Isolation Containment Types (EDICT). This report gives a brief description for each of the networks, a description of its modeling, the model itself, and evaluations of the tools used for creating the models. The methodology includes a naming convention that supports a systematic way to enumerate all of the potential failure modes.

  16. Standard model status (in search of new physics'')

    SciTech Connect

    Marciano, W.J.

    1993-03-01

    A perspective on successes and shortcomings of the standard model is given. The complementarity between direct high energy probes of new physics and lower energy searches via precision measurements and rare reactions is described. Several illustrative examples are discussed.

  17. Standard model status (in search of ``new physics``)

    SciTech Connect

    Marciano, W.J.

    1993-03-01

    A perspective on successes and shortcomings of the standard model is given. The complementarity between direct high energy probes of new physics and lower energy searches via precision measurements and rare reactions is described. Several illustrative examples are discussed.

  18. Evaluation and development of physically-based embankment breach models

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The CEATI Dam Safety Interest Group (DSIG) working group on embankment erosion and breach modelling has evaluated three physically-based numerical models used to simulate embankment erosion and breach development. The three models identified by the group were considered to be good candidates for fu...

  19. Kinetic exchange models: From molecular physics to social science

    NASA Astrophysics Data System (ADS)

    Patriarca, Marco; Chakraborti, Anirban

    2013-08-01

    We discuss several multi-agent models that have their origin in the kinetic exchange theory of statistical mechanics and have been recently applied to a variety of problems in the social sciences. This class of models can be easily adapted for simulations in areas other than physics, such as the modeling of income and wealth distributions in economics and opinion dynamics in sociology.

  20. Harmony Theory: Problem Solving, Parallel Cognitive Models, and Thermal Physics.

    ERIC Educational Resources Information Center

    Smolensky, Paul; Riley, Mary S.

    This document consists of three papers. The first, "A Parallel Model of (Sequential) Problem Solving," describes a parallel model designed to solve a class of relatively simple problems from elementary physics and discusses implications for models of problem-solving in general. It is shown that one of the most salient features of problem solving,…

  1. Rock Physic Modeling of Carbonate Sediments

    NASA Astrophysics Data System (ADS)

    Ruiz, F. J.; Dvorkin, J.; Nur, A.

    2006-12-01

    We offer an effective-medium model for estimating the elastic properties of high-porosity marine carbonate sediment. This model treats carbonate as a pack of porous elastic grains. The effective elastic moduli of the grains are calculated using the Differential Effective Medium model (DEM) where the ellipsoidal inclusions have a fixed aspect ratio and are filled with sea water. Then the elastic moduli of a pack of these grains are calculated using a modified (scaled to the critical porosity) upper Hashin-Shtrikman bound. We find that the best match between the model-predicted compressional and shear-wave velocity and ODP data from three wells is achieved for the aspect ratio 0.25. We also examine a laboratory data set for low-porosity consolidated carbonate rock. In this case we treat the grains as solid without inclusions and then use DEM to calculate the effective bulk and shear moduli of the whole rock. The best fit to the experimental data is achieved for the pore aspect ratio in the range between 0.1 and 0.2. These effective medium predictions also match the empirical Raymer's (1980) equation applied to pure calcite rock. The basic conclusion is that in spite of the apparent wide variation in the shape and size distribution of pores in carbonate, its elastic properties can be predicted by assuming a single aspect ratio (shape) of the pores. The combination of the above two models provides a predictive estimate for the elastic-wave velocity of calcite sediment (at least for the data under examination) in a wide porosity range between zero and almost 100% porosity. It is important to emphasize that our effective-medium approach assigns finite non-zero values to the shear modulus of high-porosity marine sediment unlike the suspension model commonly used in such depositional setting.

  2. Modelling Spatial Hydrologic Patterns Using Physically-Based Models Driven by Remote- Sensing and Reanalysis Data

    NASA Astrophysics Data System (ADS)

    Liu, M.; Bardossy, A.

    2008-12-01

    Due to the interaction with energy inputs (solar radiation, precipitation, and wind, etc.), natural catchments tend to evolve to an equilibrium state characterized by stable spatial patterns of vegetation, topography, soil distribution and river system, which in turn lead to stable patterns of certain hydrological variables, i.e., soil moisture, evapotranspiration, and snow cover. In this work, these three important hydrologic parameters have been investigated at a fine scale (500m to 1000m). The authors start from obtaining the spatial patterns of basic meteorological inputs with physically based models driven by globally available data, i.e., spatial solar radiation is generated by radiation models, and spatial wind is obtained by a meso-scale meteorological model driven by NCEP/NCAR reanalysis data. The SWAP model has been adapted to calculate the evapotranspiration and soil moisture at grid scale. The approach is validated in SADC (Southern African Development Community) region with the remote sensing soil moisture data available from ESA TIGER Innovator project. In a parallel study, MODIS snow cover data has been reconstructed applying a spatial and temporal filter with land surface temperature as auxiliary information, to investigate the characteristics of its spatial distribution. In both studies, statistical analysis reveals a strong relationship between the hydrological variables and topography, as well as land cover. Since the approach is based on physically based models and driven by globally available data, it is general for any catchment and time period.

  3. An Expectancy-Value Model for Sustained Enrolment Intentions of Senior Secondary Physics Students

    NASA Astrophysics Data System (ADS)

    Abraham, Jessy; Barker, Katrina

    2015-08-01

    This study investigates the predictive influences of achievement motivational variables that may sustain students' engagement in physics and influence their future enrolment plans in the subject. Unlike most studies attempting to address the decline of physics enrolments through capturing students' intention to enrol in physics before ever studying the subject, this study is novel because it captures the perceptions of students currently enrolled in senior secondary physics and their subsequent enrolment intentions after completing modules from the physics curriculum. Participants comprised of senior secondary students in year 11 completing their first year of physics in Australia across nine high schools in New South Wales. The Sustained Enrolment Models for Physics (SEMP), which drew upon the Expectancy-Value (EV) theoretical foundation, proposed predictive relations among students' achievement motivation, sustained engagement, and enrolment intentions in relation to physics. The data showed a good fit to the theoretically developed model for all four physics topics from the year 11 curriculum. The path coefficients of the models demonstrated the strength of relationships among the variables for each of the topics. The topic specificity of SEMPs allowed the mapping of students' motivational patterns at a more sensitive level than the domain-specific level and suggested that the relative influence of motivational precursors can vary by topic. This study advanced the EV research knowledge that, while values may be significant, it is the expectancies that largely predict students' sustained choice intentions in relation to physics. Implications for these findings are discussed.

  4. Numerical investigation of algebraic oceanic turbulent mixing-layer models

    NASA Astrophysics Data System (ADS)

    Chacón-Rebollo, T.; Gómez-Mármol, M.; Rubino, S.

    2013-11-01

    In this paper we investigate the finite-time and asymptotic behaviour of algebraic turbulent mixing-layer models by numerical simulation. We compare the performances given by three different settings of the eddy viscosity. We consider Richardson number-based vertical eddy viscosity models. Two of these are classical algebraic turbulence models usually used in numerical simulations of global oceanic circulation, i.e. the Pacanowski-Philander and the Gent models, while the other one is a more recent model (Bennis et al., 2010) proposed to prevent numerical instabilities generated by physically unstable configurations. The numerical schemes are based on the standard finite element method. We perform some numerical tests for relatively large deviations of realistic initial conditions provided by the Tropical Atmosphere Ocean (TAO) array. These initial conditions correspond to states close to mixing-layer profiles, measured on the Equatorial Pacific region called the West-Pacific Warm Pool. We conclude that mixing-layer profiles could be considered as kinds of "absorbing configurations" in finite time that asymptotically evolve to steady states under the application of negative surface energy fluxes.

  5. Value-Added Modeling in Physical Education

    ERIC Educational Resources Information Center

    Hushman, Glenn; Hushman, Carolyn

    2015-01-01

    The educational reform movement in the United States has resulted in a variety of states moving toward a system of value-added modeling (VAM) to measure a teacher's contribution to student achievement. Recently, many states have begun using VAM scores as part of a larger system to evaluate teacher performance. In the past decade, only "core…

  6. Using the Bifocal Modeling Framework to Resolve "Discrepant Events" Between Physical Experiments and Virtual Models in Biology

    NASA Astrophysics Data System (ADS)

    Blikstein, Paulo; Fuhrmann, Tamar; Salehi, Shima

    2016-08-01

    In this paper, we investigate an approach to supporting students' learning in science through a combination of physical experimentation and virtual modeling. We present a study that utilizes a scientific inquiry framework, which we call "bifocal modeling," to link student-designed experiments and computer models in real time. In this study, a group of high school students designed computer models of bacterial growth with reference to a simultaneous physical experiment they were conducting, and were able to validate the correctness of their model against the results of their experiment. Our findings suggest that as the students compared their virtual models with physical experiments, they encountered "discrepant events" that contradicted their existing conceptions and elicited a state of cognitive disequilibrium. This experience of conflict encouraged students to further examine their ideas and to seek more accurate explanations of the observed natural phenomena, improving the design of their computer models.

  7. A physical model of sensorimotor interactions during locomotion

    NASA Astrophysics Data System (ADS)

    Klein, Theresa J.; Lewis, M. Anthony

    2012-08-01

    In this paper, we describe the development of a bipedal robot that models the neuromuscular architecture of human walking. The body is based on principles derived from human muscular architecture, using muscles on straps to mimic agonist/antagonist muscle action as well as bifunctional muscles. Load sensors in the straps model Golgi tendon organs. The neural architecture is a central pattern generator (CPG) composed of a half-center oscillator combined with phase-modulated reflexes that is simulated using a spiking neural network. We show that the interaction between the reflex system, body dynamics and CPG results in a walking cycle that is entrained to the dynamics of the system. We also show that the CPG helped stabilize the gait against perturbations relative to a purely reflexive system, and compared the joint trajectories to human walking data. This robot represents a complete physical, or ‘neurorobotic’, model of the system, demonstrating the usefulness of this type of robotics research for investigating the neurophysiological processes underlying walking in humans and animals.

  8. Three-Dimensional Ultrasound-Derived Physical Mitral Valve Modeling

    PubMed Central

    Witschey, Walter RT; Pouch, Alison M; McGarvey, Jeremy R; Ikeuchi, Kaori; Contijoch, Francisco; Levack, Melissa M; Yushkevick, Paul A; Sehgal, Chandra M; Jackson, Benjamin; Gorman, Robert C; Gorman, Joseph H

    2015-01-01

    Purpose Advances in mitral valve repair and adoption have been partly attributed to improvements in echocardiographic imaging technology. To further educate and guide repair surgery, we have developed a methodology to quickly produce physical models of the valve using novel 3D echocardiographic imaging software in combination with stereolithographic printing. Description Quantitative virtual mitral valve shape models were developed from 3D transesophageal echocardiographic images using software based on semi-automated image segmentation and continuous medial representation (cm-rep) algorithms. These quantitative virtual shape models were then used as input to a commercially available stereolithographic printer to generate a physical model of the each valve at end systole and end diastole. Evaluation Physical models of normal and diseased valves (ischemic mitral regurgitation and myxomatous degeneration) were constructed. There was good correspondence between the virtual shape models and physical models. Conclusions It was feasible to create a physical model of mitral valve geometry under normal, ischemic and myxomatous valve conditions using 3D printing of 3D echocardiographic data. Printed valves have the potential to guide surgical therapy for mitral valve disease. PMID:25087790

  9. Search for physics beyond the Standard Model using jet observables

    NASA Astrophysics Data System (ADS)

    Kousouris, Konstantinos

    2015-11-01

    Jet observables have been exploited extensively during the LHC Run 1 to search for physics beyond the Standard Model. In this article, the most recent results from the ATLAS and CMS collaborations are summarized. Data from proton-proton collisions at 7 and 8 TeV center-of-mass energy have been analyzed to study monojet, dijet, and multijet final states, searching for a variety of new physics signals that include colored resonances, contact interactions, extra dimensions, and supersymmetric particles. The exhaustive searches with jets in Run 1 did not reveal any signal, and the results were used to put stringent exclusion limits on the new physics models.

  10. A physical model for z ~ 2 dust-obscured galaxies

    NASA Astrophysics Data System (ADS)

    Narayanan, Desika; Dey, Arjun; Hayward, Christopher C.; Cox, Thomas J.; Bussmann, R. Shane; Brodwin, Mark; Jonsson, Patrik; Hopkins, Philip F.; Groves, Brent; Younger, Joshua D.; Hernquist, Lars

    2010-09-01

    We present a physical model for the origin of z ~ 2 dust-obscured galaxies (DOGs), a class of high-redshift ultraluminous infrared galaxies (ULIRGs) selected at 24μm which are particularly optically faint (F24μm/FR > 1000). By combining N-body/smoothed particle hydrodynamic simulations of high-redshift galaxy evolution with 3D polychromatic dust radiative transfer models, we find that luminous DOGs (with F24 >~ 0.3mJy at z ~ 2) are well modelled as extreme gas-rich mergers in massive (~5 × 1012-1013Msolar) haloes, with elevated star formation rates (SFR; ~500-1000Msolaryr-1) and/or significant active galactic nuclei (AGN) growth , whereas less luminous DOGs are more diverse in nature. At final coalescence, merger-driven DOGs transition from being starburst dominated to AGN dominated, evolving from a `bump' to a power-law (PL) shaped mid-IR (Infrared Array Camera, IRAC) spectral energy distribution (SED). After the DOG phase, the galaxy settles back to exhibiting a `bump' SED with bluer colours and lower SFRs. While canonically PL galaxies are associated with being AGN dominated, we find that the PL mid-IR SED can owe both to direct AGN contribution and to a heavily dust obscured stellar bump at times that the galaxy is starburst dominated. Thus, PL galaxies can be either starburst or AGN dominated. Less luminous DOGs can be well-represented either by mergers or by massive (Mbaryon ~ 5 × 1011Msolar) secularly evolving gas-rich disc galaxies (with SFR >~ 50Msolaryr-1). By utilizing similar models as those employed in the submillimetre galaxy (SMG) formation study of Narayanan et al., we investigate the connection between DOGs and SMGs. We find that the most heavily star-forming merger-driven DOGs can be selected as submillimetre galaxies, while both merger-driven and secularly evolving DOGs typically satisfy the BzK selection criteria. The model SEDs from the simulated galaxies match observed data reasonably well, though Mrk 231 and Arp 220 templates provide

  11. Validation and upgrading of physically based mathematical models

    NASA Technical Reports Server (NTRS)

    Duval, Ronald

    1992-01-01

    The validation of the results of physically-based mathematical models against experimental results was discussed. Systematic techniques are used for: (1) isolating subsets of the simulator mathematical model and comparing the response of each subset to its experimental response for the same input conditions; (2) evaluating the response error to determine whether it is the result of incorrect parameter values, incorrect structure of the model subset, or unmodeled external effects of cross coupling; and (3) modifying and upgrading the model and its parameter values to determine the most physically appropriate combination of changes.

  12. Role Modeling Attitudes, Physical Activity and Fitness Promoting Behaviors of Prospective Physical Education Specialists and Non-Specialists.

    ERIC Educational Resources Information Center

    Cardinal, Bradley J.; Cardinal, Marita K.

    2002-01-01

    Compared the role modeling attitudes and physical activity and fitness promoting behaviors of undergraduate students majoring in physical education and in elementary education. Student teacher surveys indicated that physical education majors had more positive attitudes toward role modeling physical activity and fitness promoting behaviors and…

  13. Characterizing, modeling, and addressing gender disparities in introductory college physics

    NASA Astrophysics Data System (ADS)

    Kost-Smith, Lauren Elizabeth

    2011-12-01

    The underrepresentation and underperformance of females in physics has been well documented and has long concerned policy-makers, educators, and the physics community. In this thesis, we focus on gender disparities in the first- and second-semester introductory, calculus-based physics courses at the University of Colorado. Success in these courses is critical for future study and careers in physics (and other sciences). Using data gathered from roughly 10,000 undergraduate students, we identify and model gender differences in the introductory physics courses in three areas: student performance, retention, and psychological factors. We observe gender differences on several measures in the introductory physics courses: females are less likely to take a high school physics course than males and have lower standardized mathematics test scores; males outscore females on both pre- and post-course conceptual physics surveys and in-class exams; and males have more expert-like attitudes and beliefs about physics than females. These background differences of males and females account for 60% to 70% of the gender gap that we observe on a post-course survey of conceptual physics understanding. In analyzing underlying psychological factors of learning, we find that female students report lower self-confidence related to succeeding in the introductory courses (self-efficacy) and are less likely to report seeing themselves as a "physics person". Students' self-efficacy beliefs are significant predictors of their performance, even when measures of physics and mathematics background are controlled, and account for an additional 10% of the gender gap. Informed by results from these studies, we implemented and tested a psychological, self-affirmation intervention aimed at enhancing female students' performance in Physics 1. Self-affirmation reduced the gender gap in performance on both in-class exams and the post-course conceptual physics survey. Further, the benefit of the self

  14. Atomistic Model of Physical Ageing in Se-rich As-Se Glasses

    SciTech Connect

    Golovchak,R.; Shpotyuk, O.; Kozdras, A.; Bureau, B.; Vlcek, M.; Ganjoo, A.; Jain, H.

    2007-01-01

    Thermal, optical, X-ray excited and magnetic methods were used to develop a microstructural model of physical ageing in Se-rich glasses. The glass composition As10Se90, possessing a typical cross-linked chain structure, was chosen as a model object for the investigations. The effect of physical ageing in this glass was revealed by differential scanning calorimetry, whereas the corresponding changes in its atomic arrangement were studied by extended X-ray absorption fine structure, Raman and solid-state 77Se nuclear magnetic resonance spectroscopy. Straightening-shrinkage processes are shown to be responsible for the physical ageing in this Se-rich As-Se glass.

  15. A GLOBAL PHYSICAL MODEL FOR CEPHEIDS

    SciTech Connect

    Pejcha, Ondrej; Kochanek, Christopher S. E-mail: ckochanek@astronomy.ohio-state.edu

    2012-04-01

    We perform a global fit to {approx}5000 radial velocity and {approx}177, 000 magnitude measurements in 29 photometric bands covering 0.3 {mu}m to 8.0 {mu}m distributed among 287 Galactic, Large Magellanic Cloud, and Small Magellanic Cloud Cepheids with P > 10 days. We assume that the Cepheid light curves and radial velocities are fully characterized by distance, reddening, and time-dependent radius and temperature variations. We construct phase curves of radius and temperature for periods between 10 and 100 days, which yield light-curve templates for all our photometric bands and can be easily generalized to any additional band. With only four to six parameters per Cepheid, depending on the existence of velocity data and the amount of freedom in the distance, the models have typical rms light and velocity curve residuals of 0.05 mag and 3.5 km s{sup -1}. The model derives the mean Cepheid spectral energy distribution and its derivative with respect to temperature, which deviate from a blackbody in agreement with metal-line and molecular opacity effects. We determine a mean reddening law toward the Cepheids in our sample, which is not consistent with standard assumptions in either the optical or near-IR. Based on stellar atmosphere models, we predict the biases in distance, reddening, and temperature determinations due to the metallicity and quantify the metallicity signature expected for our fit residuals. The observed residuals as a function of wavelength show clear differences between the individual galaxies, which are compatible with these predictions. In particular, we find that metal-poor Cepheids appear hotter. Finally, we provide a framework for optimally selecting filters that yield the smallest overall errors in Cepheid parameter determination or filter combinations for suppressing or enhancing the metallicity effects on distance determinations. We make our templates publicly available.

  16. Application of physical parameter identification to finite element models

    NASA Technical Reports Server (NTRS)

    Bronowicki, Allen J.; Lukich, Michael S.; Kuritz, Steven P.

    1986-01-01

    A time domain technique for matching response predictions of a structural dynamic model to test measurements is developed. Significance is attached to prior estimates of physical model parameters and to experimental data. The Bayesian estimation procedure allows confidence levels in predicted physical and modal parameters to be obtained. Structural optimization procedures are employed to minimize an error functional with physical model parameters describing the finite element model as design variables. The number of complete FEM analyses are reduced using approximation concepts, including the recently developed convoluted Taylor series approach. The error function is represented in closed form by converting free decay test data to a time series model using Prony' method. The technique is demonstrated on simulated response of a simple truss structure.

  17. The limitations of mathematical modeling in high school physics education

    NASA Astrophysics Data System (ADS)

    Forjan, Matej

    The theme of the doctoral dissertation falls within the scope of didactics of physics. Theoretical analysis of the key constraints that occur in the transmission of mathematical modeling of dynamical systems into field of physics education in secondary schools is presented. In an effort to explore the extent to which current physics education promotes understanding of models and modeling, we analyze the curriculum and the three most commonly used textbooks for high school physics. We focus primarily on the representation of the various stages of modeling in the solved tasks in textbooks and on the presentation of certain simplifications and idealizations, which are in high school physics frequently used. We show that one of the textbooks in most cases fairly and reasonably presents the simplifications, while the other two half of the analyzed simplifications do not explain. It also turns out that the vast majority of solved tasks in all the textbooks do not explicitly represent model assumptions based on what we can conclude that in high school physics the students do not develop sufficiently a sense of simplification and idealizations, which is a key part of the conceptual phase of modeling. For the introduction of modeling of dynamical systems the knowledge of students is also important, therefore we performed an empirical study on the extent to which high school students are able to understand the time evolution of some dynamical systems in the field of physics. The research results show the students have a very weak understanding of the dynamics of systems in which the feedbacks are present. This is independent of the year or final grade in physics and mathematics. When modeling dynamical systems in high school physics we also encounter the limitations which result from the lack of mathematical knowledge of students, because they don't know how analytically solve the differential equations. We show that when dealing with one-dimensional dynamical systems

  18. Physics beyond the Standard Model from hydrogen spectroscopy

    NASA Astrophysics Data System (ADS)

    Ubachs, W.; Koelemeij, J. C. J.; Eikema, K. S. E.; Salumbides, E. J.

    2016-02-01

    Spectroscopy of hydrogen can be used for a search into physics beyond the Standard Model. Differences between the absorption spectra of the Lyman and Werner bands of H2 as observed at high redshift and those measured in the laboratory can be interpreted in terms of possible variations of the proton-electron mass ratio μ =mp /me over cosmological history. Investigation of ten such absorbers in the redshift range z = 2.0 -4.2 yields a constraint of | Δμ / μ | < 5 ×10-6 at 3σ. Observation of H2 from the photospheres of white dwarf stars inside our Galaxy delivers a constraint of similar magnitude on a dependence of μ on a gravitational potential 104 times as strong as on the Earth's surface. While such astronomical studies aim at finding quintessence in an indirect manner, laboratory precision measurements target such additional quantum fields in a direct manner. Laser-based precision measurements of dissociation energies, vibrational splittings and rotational level energies in H2 molecules and their deuterated isotopomers HD and D2 produce values for the rovibrational binding energies fully consistent with quantum ab initio calculations including relativistic and quantum electrodynamical (QED) effects. Similarly, precision measurements of high-overtone vibrational transitions of HD+ ions, captured in ion traps and sympathetically cooled to mK temperatures, also result in transition frequencies fully consistent with calculations including QED corrections. Precision measurements of inter-Rydberg transitions in H2 can be extrapolated to yield accurate values for level splittings in the H2+ -ion. These comprehensive results of laboratory precision measurements on neutral and ionic hydrogen molecules can be interpreted to set bounds on the existence of possible fifth forces and of higher dimensions, phenomena describing physics beyond the Standard Model.

  19. Sediment dynamics in the Adriatic Sea investigated with coupled models

    USGS Publications Warehouse

    Sherwood, Christopher R.; Book, Jeffrey W.; Carniel, Sandro; Cavaleri, Luigi; Chiggiato, Jacopo; Das, Himangshu; Doyle, James D.; Harris, Courtney K.; Niedoroda, Alan W.; Perkins, Henry; Poulain, Pierre-Marie; Pullen, Julie; Reed, Christopher W.; Russo, Aniello; Sclavo, Mauro; Signell, Richard P.; Traykovski, Peter A.; Warner, John C.

    2004-01-01

    Several large research programs focused on the Adriatic Sea in winter 2002-2003, making it an exciting place for sediment dynamics modelers (Figure 1). Investigations of atmospheric forcing and oceanic response (including wave generation and propagation, water-mass formation, stratification, and circulation), suspended material, bottom boundary layer dynamics, bottom sediment, and small-scale stratigraphy were performed by European and North American researchers participating in several projects. The goal of EuroSTRATAFORM researchers is to improve our ability to understand and simulate the physical processes that deliver sediment to the marine environment and generate stratigraphic signatures. Scientists involved in the Po and Apennine Sediment Transport and Accumulation (PASTA) experiment benefited from other major research programs including ACE (Adriatic Circulation Experiment), DOLCE VITA (Dynamics of Localized Currents and Eddy Variability in the Adriatic), EACE (the Croatian East Adriatic Circulation Experiment project), WISE (West Istria Experiment), and ADRICOSM (Italian nowcasting and forecasting) studies.

  20. Numerical and measured data from the 3D salt canopy physical modeling project

    SciTech Connect

    Bradley, C.; House, L.; Fehler, M.; Pearson, J.; TenCate, J.; Wiley, R.

    1997-11-01

    The evolution of salt structures in the Gulf of Mexico have been shown to provide a mechanism for the trapping of significant hydrocarbon reserves. Most of these structures have complex geometries relative to the surrounding sedimentary layers. This aspect in addition to high velocities within the salt tend to scatter and defocus seismic energy and make imaging of subsalt lithology extremely difficult. An ongoing program the SEG/EAEG modeling project (Aminzadeh et al. 1994a: Aminzadeh et al. 1994b: Aminzadeh et al. 1995), and a follow-up project funded as part of the Advanced Computational Technology Initiative (ACTI) (House et al. 1996) have sought to investigate problems with imaging beneath complex salt structures using numerical modeling and more recently, construction of a physical model patterned after the numerical subsalt model (Wiley and McKnight. 1996). To date, no direct comparison of the numerical and physical aspects of these models has been attempted. We present the results of forward modeling a numerical realization of the 3D salt canopy physical model with the French Petroleum Institute (IFP) acoustic finite difference algorithm used in the numerical subsalt tests. We compare the results from the physical salt canopy model, the acoustic modeling of the physical/numerical model and the original numerical SEG/EAEG Salt Model. We will be testing the sensitivity of migration to the presence of converted shear waves and acquisition geometry.

  1. "Let's get physical": advantages of a physical model over 3D computer models and textbooks in learning imaging anatomy.

    PubMed

    Preece, Daniel; Williams, Sarah B; Lam, Richard; Weller, Renate

    2013-01-01

    Three-dimensional (3D) information plays an important part in medical and veterinary education. Appreciating complex 3D spatial relationships requires a strong foundational understanding of anatomy and mental 3D visualization skills. Novel learning resources have been introduced to anatomy training to achieve this. Objective evaluation of their comparative efficacies remains scarce in the literature. This study developed and evaluated the use of a physical model in demonstrating the complex spatial relationships of the equine foot. It was hypothesized that the newly developed physical model would be more effective for students to learn magnetic resonance imaging (MRI) anatomy of the foot than textbooks or computer-based 3D models. Third year veterinary medicine students were randomly assigned to one of three teaching aid groups (physical model; textbooks; 3D computer model). The comparative efficacies of the three teaching aids were assessed through students' abilities to identify anatomical structures on MR images. Overall mean MRI assessment scores were significantly higher in students utilizing the physical model (86.39%) compared with students using textbooks (62.61%) and the 3D computer model (63.68%) (P < 0.001), with no significant difference between the textbook and 3D computer model groups (P = 0.685). Student feedback was also more positive in the physical model group compared with both the textbook and 3D computer model groups. Our results suggest that physical models may hold a significant advantage over alternative learning resources in enhancing visuospatial and 3D understanding of complex anatomical architecture, and that 3D computer models have significant limitations with regards to 3D learning.

  2. Progress in Hadronic Physics Modelling in Geant4

    SciTech Connect

    Apostolakis, John; Folger, Gunter; Grichine, Vladimir; Heikkinen, Aatos; Howard, Alexander; Ivanchenko, Vladimir; Kaitaniemi, Pekka; Koi, Tatsumi; Kosov, Mikhail; Quesada, Jose Manuel; Ribon, Alberto; Uzhinsky, Vladimir; Wright, Dennis; /SLAC

    2011-11-28

    Geant4 offers a set of models to simulate hadronic showers in calorimeters. Recent improvements to several models relevant to the modelling of hadronic showers are discussed. These include improved cross sections, a revision of the FTF model, the addition of quasi-elastic scattering to the QGS model, and enhancements in the nuclear precompound and de-excitation models. The validation of physics models against thin target experiments has been extended especially in the energy region 10 GeV and below. Examples of new validation results are shown.

  3. Applying Transtheoretical Model to Promote Physical Activities Among Women

    PubMed Central

    Pirzadeh, Asiyeh; Mostafavi, Firoozeh; Ghofranipour, Fazllolah; Feizi, Awat

    2015-01-01

    Background: Physical activity is one of the most important indicators of health in communities but different studies conducted in the provinces of Iran showed that inactivity is prevalent, especially among women. Objectives: Inadequate regular physical activities among women, the importance of education in promoting the physical activities, and lack of studies on the women using transtheoretical model, persuaded us to conduct this study with the aim of determining the application of transtheoretical model in promoting the physical activities among women of Isfahan. Materials and Methods: This research was a quasi-experimental study which was conducted on 141 women residing in Isfahan, Iran. They were randomly divided into case and control groups. In addition to the demographic information, their physical activities and the constructs of the transtheoretical model (stages of change, processes of change, decisional balance, and self-efficacy) were measured at 3 time points; preintervention, 3 months, and 6 months after intervention. Finally, the obtained data were analyzed through t test and repeated measures ANOVA test using SPSS version 16. Results: The results showed that education based on the transtheoretical model significantly increased physical activities in 2 aspects of intensive physical activities and walking, in the case group over the time. Also, a high percentage of people have shown progress during the stages of change, the mean of the constructs of processes of change, as well as pros and cons. On the whole, a significant difference was observed over the time in the case group (P < 0.01). Conclusions: This study showed that interventions based on the transtheoretical model can promote the physical activity behavior among women. PMID:26834796

  4. Investigation of Thermal Creep and Thermal Stress Effects in Microgravity Physical Vapor Transport

    NASA Technical Reports Server (NTRS)

    Mackowski, D. W. (Principal Investigator); Knight, R. W. (Principal Investigator)

    1996-01-01

    Reported here are the results of our numerical investigation into the mechanisms which affect the transport and growth processes in physical vapor transport (PVT) crystal growth ampoules. The first part of the report consists of a brief summary of the major accomplishments and conclusions of our work. The second part consists of two manuscripts, submitted to the Journal of Crystal Growth, which provided a detailed description of the findings in our investigation.

  5. Physical modeling of air flow during air sparging remediation.

    PubMed

    Hu, Liming; Wu, Xiaofeng; Liu, Yan; Meegoda, Jay N; Gao, Shengyan

    2010-05-15

    Air sparging (AS) is one of the most efficient techniques for remediating saturated soils and groundwater contaminated with volatile organic compounds. A series of physical modeling tests for different sizes of porous media under varied injection pressure were conducted to investigate the effect of particle size and air injection pressure on size and shape of the zone of influence (ZOI). The test results show that ZOI can be expressed by two components: the horizontal expansion due to pneumatic fracture or preferential intrusion around the injection point and the angle of ZOI which is the angle between the vertical line and the boundary of ZOI. There exists a limited angle of ZOI for each type of porous media. The measured minimum and maximum air injection pressures in 1g tests are compared with corresponding theoretical values, and it is found that the measured minimum injection pressure is slightly lower than the theoretical value, while the measured maximum injection pressure is much higher than the theoretical maximum injection pressure. Centrifugal test results confirmed nonapplicability of theoretical maximum injection pressure to air sparging design. All of the above provide valuable information for design and theoretical modeling of air sparging for groundwater remediation.

  6. Technical Manual for the SAM Physical Trough Model

    SciTech Connect

    Wagner, M. J.; Gilman, P.

    2011-06-01

    NREL, in conjunction with Sandia National Lab and the U.S Department of Energy, developed the System Advisor Model (SAM) analysis tool for renewable energy system performance and economic analysis. This paper documents the technical background and engineering formulation for one of SAM's two parabolic trough system models in SAM. The Physical Trough model calculates performance relationships based on physical first principles where possible, allowing the modeler to predict electricity production for a wider range of component geometries than is possible in the Empirical Trough model. This document describes the major parabolic trough plant subsystems in detail including the solar field, power block, thermal storage, piping, auxiliary heating, and control systems. This model makes use of both existing subsystem performance modeling approaches, and new approaches developed specifically for SAM.

  7. Spin-foam models and the physical scalar product

    SciTech Connect

    Alesci, Emanuele; Noui, Karim; Sardelli, Francesco

    2008-11-15

    This paper aims at clarifying the link between loop quantum gravity and spin-foam models in four dimensions. Starting from the canonical framework, we construct an operator P acting on the space of cylindrical functions Cyl({gamma}), where {gamma} is the four-simplex graph, such that its matrix elements are, up to some normalization factors, the vertex amplitude of spin-foam models. The spin-foam models we are considering are the topological model, the Barrett-Crane model, and the Engle-Pereira-Rovelli model. If one of these spin-foam models provides a covariant quantization of gravity, then the associated operator P should be the so-called ''projector'' into physical states and its matrix elements should give the physical scalar product. We discuss the possibility to extend the action of P to any cylindrical functions on the space manifold.

  8. Model Rocketry in the 21st-Century Physics Classroom

    NASA Astrophysics Data System (ADS)

    Horst, Ken

    2004-10-01

    Model rocketry has changed since my introduction to it as an eighth-grade student. Two of these changes are important for the use of rocketry in the physics classroom. First, simulation software, which is relatively inexpensive and very powerful, allows students to create and fly virtual models of their rocket designs. Second, lightweight and sophisticated electronics2 are available for logging flight data and for controlling flight operations such as deploying parachutes. In this technology-rich context, designing, building, and flying model rockets can capture the interest of today's physics students.

  9. Quantum monadology: a consistent world model for consciousness and physics.

    PubMed

    Nakagomi, Teruaki

    2003-04-01

    The NL world model presented in the previous paper is embodied by use of relativistic quantum mechanics, which reveals the significance of the reduction of quantum states and the relativity principle, and locates consciousness and the concept of flowing time consistently in physics. This model provides a consistent framework to solve apparent incompatibilities between consciousness (as our interior experience) and matter (as described by quantum mechanics and relativity theory). Does matter have an inside? What is the flowing time now? Does physics allow the indeterminism by volition? The problem of quantum measurement is also resolved in this model.

  10. Investigating Middle School Students' Ability to Develop Energy as a Framework for Analyzing Simple Physical Phenomena

    ERIC Educational Resources Information Center

    Papadouris, Nicos; Constantinou, Constantinos P.

    2016-01-01

    We investigated whether it is possible for 12-year-old students to develop a qualitative conceptualization of energy and four associate features (forms of energy, transfer processes, conservation, and degradation) as a framework for constructing interpretive accounts for the operation of physical phenomena (specifically, for changes taking place…

  11. An Investigation of Students' Embodied Discourses in Physical Education: A Gender Project

    ERIC Educational Resources Information Center

    Azzarito, Laura; Solmon, Melinda

    2009-01-01

    Despite significant theoretical and practical progress over the past 20 years, the social construction of gender and its link to youths' participation in physical activity in school contexts remain critical issues that call for further socioeducational scrutiny. In this study, researchers investigated the ways students' embodiment of discursive…

  12. Investigating Factors in the Retention of Students in High School Physical Education

    ERIC Educational Resources Information Center

    Lodewyk, Ken R.; Pybus, Colin M.

    2013-01-01

    Several studies have reported declining student enrolment rates in optional physical education. This study--incorporating constructs from social cognitive, self-determination, and body image theory--investigated factors that might be influential to this trend. Surveys were administered to 227 tenth-grade students from five schools in one school…

  13. An Investigation of the Self-Regulation Components Students Employ in the Physical Education Setting

    ERIC Educational Resources Information Center

    Kermarrec, Gilles; Todorovich, John; Fleming, David

    2004-01-01

    Research in educational psychology and sport psychology indicates that school achievement depends on students' capacity to self-regulate their own learning processes. The purpose of this study was to investigate the self-regulation components employed by students in a natural physical education setting. Twenty-three French students, 14 and 15…

  14. Investigation of Professional Self Sufficiency Levels of Physical Education and Sports Teachers

    ERIC Educational Resources Information Center

    Saracaoglu, Asuman Seda; Ozsaker, Murat; Varol, Rana

    2012-01-01

    The present research aimed at detecting professional self sufficiency levels of physical education and sports teachers who worked in Izmir Province and at investigating them in terms of some variables. For data collection, Teacher's Sense of Efficacy Scale-developed by Moran and Woolfolk-Hoy (2001) and Turkish validity and reliability studies…

  15. PE on YouTube--Investigating Participation in Physical Education Practice

    ERIC Educational Resources Information Center

    Quennerstedt, Mikael

    2013-01-01

    Background: In this article, students' diverse ways of participating in physical education (PE) practice shown in clips on YouTube were investigated. YouTube is the largest user-generated video-sharing website on the Internet, where different video content is presented. The clips on YouTube, as used in this paper, can be seen as a user-generated…

  16. Snyder-de Sitter model from two-time physics

    SciTech Connect

    Carrisi, M. C.; Mignemi, S.

    2010-11-15

    We show that the symplectic structure of the Snyder model on a de Sitter background can be derived from two-time physics in seven dimensions and propose a Hamiltonian for a free particle consistent with the symmetries of the model.

  17. Rock.XML - Towards a library of rock physics models

    NASA Astrophysics Data System (ADS)

    Jensen, Erling Hugo; Hauge, Ragnar; Ulvmoen, Marit; Johansen, Tor Arne; Drottning, Åsmund

    2016-08-01

    Rock physics modelling provides tools for correlating physical properties of rocks and their constituents to the geophysical observations we measure on a larger scale. Many different theoretical and empirical models exist, to cover the range of different types of rocks. However, upon reviewing these, we see that they are all built around a few main concepts. Based on this observation, we propose a format for digitally storing the specifications for rock physics models which we have named Rock.XML. It does not only contain data about the various constituents, but also the theories and how they are used to combine these building blocks to make a representative model for a particular rock. The format is based on the Extensible Markup Language XML, making it flexible enough to handle complex models as well as scalable towards extending it with new theories and models. This technology has great advantages as far as documenting and exchanging models in an unambiguous way between people and between software. Rock.XML can become a platform for creating a library of rock physics models; making them more accessible to everyone.

  18. Applying Socioecological Model to Improve Women’s Physical Activity: A Randomized Control Trial

    PubMed Central

    Tehrani, Hadi; Majlessi, Fershteh; Shojaeizadeh, Davoud; Sadeghi, Roya; Hasani Kabootarkhani, Marzieh

    2016-01-01

    Background: A sedentary life without sufficient physical activity is recognized as a risk factor for various diseases, and a major modifiable risk factor for noncommunicable diseases. This study was conducted to investigate the effect of intervention using socioecological model in promoting women’s physical activity in the city of Kerman, Iran. Materials and Methods: In this randomized, double-blinded, controlled study, 360 women were studied at health and medical centers of Kerman. This educational intervention was based on socioecological model and conducted on 4 levels of personal, social, organizational, and political. Data collection tool included a researcher-made questionnaire based on constructs of socioecological model and the international physical activity inventory. Results: The results indicated insignificant differences between the two groups in terms of perceived social, physical, and political support and also with regard to level of physical activity before intervention. However after the intervention and according to independent t test, significant differences were observed between two groups in perceived social, physical, and political support and also level of physical activity (P < 0.001). Furthermore, mean values of the above terms increased in the intervention group. Conclusions: According to the results, interventions based on socioecological model can positively affect women’s physical activity. PMID:27247781

  19. Beyond Standard Model Physics: At the Frontiers of Cosmology and Particle Physics

    NASA Astrophysics Data System (ADS)

    Lopez-Suarez, Alejandro O.

    I begin to write this thesis at a time of great excitement in the field of cosmology and particle physics. The aim of this thesis is to study and search for beyond the standard model (BSM) physics in the cosmological and high energy particle fields. There are two main questions, which this thesis aims to address: 1) what can we learn about the inflationary epoch utilizing the pioneer gravitational wave detector Adv. LIGO?, and 2) what are the dark matter particle properties and interactions with the standard model particles?. This thesis will focus on advances in answering both questions.

  20. Using resource graphs to model learning in physics.

    NASA Astrophysics Data System (ADS)

    Wittmann, Michael

    2007-04-01

    Physics education researchers have many valuable ways of describing student reasoning while learning physics. One can describe the correct physics and look at specific student difficulties, for example, though that doesn't quite address the issue of how the latter develops into the former. A recent model (building on work by A.A. diSessa and D. Hammer) is to use resource graphs, which are networks of connected, small-scale ideas that describe reasoning about a specific physics topic in a specific physics context. We can compare resource graphs before and after instruction to represent conceptual changes that occur during learning. The representation describes several well documented forms of conceptual change and suggests others. I will apply the resource graphs representation to describe reasoning about energy loss in quantum tunneling. I will end the talk with a brief discussion (in the context of Newton's Laws) of how a resource perspective affects our instructional choices.

  1. The Effects of a Model-Based Physics Curriculum Program with a Physics First Approach: A Causal-Comparative Study

    ERIC Educational Resources Information Center

    Liang, Ling L.; Fulmer, Gavin W.; Majerich, David M.; Clevenstine, Richard; Howanski, Raymond

    2012-01-01

    The purpose of this study is to examine the effects of a model-based introductory physics curriculum on conceptual learning in a Physics First (PF) Initiative. This is the first comparative study in physics education that applies the Rasch modeling approach to examine the effects of a model-based curriculum program combined with PF in the United…

  2. The relation between student motivation and student grades in physical education: A 3-year investigation.

    PubMed

    Barkoukis, V; Taylor, I; Chanal, J; Ntoumanis, N

    2014-10-01

    Enhancing students' academic engagement is the key element of the educational process; hence, research in this area has focused on understanding the mechanisms that can lead to increased academic engagement. The present study investigated the relation between motivation and grades in physical education (PE) employing a 3-year longitudinal design. Three hundred fifty-four Greek high school students participated in the study. Students completed measures of motivation to participate in PE on six occasions; namely, at the start and the end of the school year in the first, second, and third year of junior high school. Students' PE grades were also recorded at these time points. The results of the multilevel growth models indicated that students' PE grades increased over the 3 years and students had better PE grades at the end of each year than at the beginning of the subsequent year. In general, students and classes with higher levels of controlling motivation achieved lower PE grades, whereas higher levels of autonomous motivation were associated with higher PE grades. These findings provide new insight on the associations between class- and individual-level motivation with objectively assessed achievement in PE.

  3. Investigating the Place and Meaning of "Physical Education" to Preschool Children: Methodological Lessons from a Research Study

    ERIC Educational Resources Information Center

    McEvilly, Nollaig

    2015-01-01

    Preschool physical education has not been extensively researched. Furthermore, research in physical activity and physical education rarely seeks young children's perspectives. The current paper focuses on one aspect of a post-structural study concerned with investigating the place and meaning of "physical education" to practitioners…

  4. Search for Beyond the Standard Model Physics at D0

    SciTech Connect

    Kraus, James

    2011-08-01

    The standard model (SM) of particle physics has been remarkably successful at predicting the outcomes of particle physics experiments, but there are reasons to expect new physics at the electroweak scale. Over the last several years, there have been a number of searches for beyond the standard model (BSM) physics at D0. Here, we limit our focus to three: searches for diphoton events with large missing transverse energy (E{sub T}), searches for leptonic jets and E{sub T}, and searches for single vector-like quarks. We have discussed three recent searches at D0. There are many more, including limits on heavy neutral gauge boson in the ee channel, a search for scalar top quarks, a search for quirks, and limits on a new resonance decaying to WW or WZ.

  5. A physical model of Titan's aerosols.

    PubMed

    Toon, O B; McKay, C P; Griffith, C A; Turco, R P

    1992-01-01

    Microphysical simulations of Titan's stratospheric haze show that aerosol microphysics is linked to organized dynamical processes. The detached haze layer may be a manifestation of 1 cm sec-1 vertical velocities at altitudes above 300 km. The hemispherical asymmetry in the visible albedo may be caused by 0.05 cm sec-1 vertical velocities at altitudes of 150 to 200 km, we predict contrast reversal beyond 0.6 micrometer. Tomasko and Smith's (1982, Icarus 51, 65-95) model, in which a layer of large particles above 220 km altitude is responsible for the high forward scattering observed by Rages and Pollack (1983, Icarus 55, 50-62), is a natural outcome of the detached haze layer being produced by rising motions if aerosol mass production occurs primarily below the detached haze layer. The aerosol's electrical charge is critical for the particle size and optical depth of the haze. The geometric albedo, particularly in the ultraviolet and near infrared, requires that the particle size be near 0.15 micrometer down to altitudes below 100 km, which is consistent with polarization observations (Tomasko and Smith 1982, West and Smith 1991, Icarus 90, 330-333). Above about 400 km and below about 150 km Yung et al.'s (1984, Astrophys. J. Suppl. Ser. 55, 465-506) diffusion coefficients are too small. Dynamical processes control the haze particles below about 150 km. The relatively large eddy diffusion coefficients in the lower stratosphere result in a vertically extensive region with nonuniform mixing ratios of condensable gases, so that most hydrocarbons may condense very near the tropopause rather than tens of kilometers above it. The optical depths of hydrocarbon clouds are probably less than one, requiring that abundant gases such as ethane condense on a subset of the haze particles to create relatively large, rapidly removed particles. The wavelength dependence of the optical radius is calculated for use in analyzing observations of the geometric albedo. The lower

  6. Physical and numerical modeling of Joule-heated melters

    NASA Astrophysics Data System (ADS)

    Eyler, L. L.; Skarda, R. J.; Crowder, R. S., III; Trent, D. S.; Reid, C. R.; Lessor, D. L.

    1985-10-01

    The Joule-heated ceramic-lined melter is an integral part of the high level waste immobilization process under development by the US Department of Energy. Scaleup and design of this waste glass melting furnace requires an understanding of the relationships between melting cavity design parameters and the furnace performance characteristics such as mixing, heat transfer, and electrical requirements. Developing empirical models of these relationships through actual melter testing with numerous designs would be a very costly and time consuming task. Additionally, the Pacific Northwest Laboratory (PNL) has been developing numerical models that simulate a Joule-heated melter for analyzing melter performance. This report documents the method used and results of this modeling effort. Numerical modeling results are compared with the more conventional, physical modeling results to validate the approach. Also included are the results of numerically simulating an operating research melter at PNL. Physical Joule-heated melters modeling results used for qualiying the simulation capabilities of the melter code included: (1) a melter with a single pair of electrodes and (2) a melter with a dual pair (two pairs) of electrodes. The physical model of the melter having two electrode pairs utilized a configuration with primary and secondary electrodes. The principal melter parameters (the ratio of power applied to each electrode pair, modeling fluid depth, electrode spacing) were varied in nine tests of the physical model during FY85. Code predictions were made for five of these tests. Voltage drops, temperature field data, and electric field data varied in their agreement with the physical modeling results, but in general were judged acceptable.

  7. Physical and numerical modeling of Joule-heated melters

    SciTech Connect

    Eyler, L.L.; Skarda, R.J.; Crowder, R.S. III; Trent, D.S.; Reid, C.R.; Lessor, D.L.

    1985-10-01

    The Joule-heated ceramic-lined melter is an integral part of the high level waste immobilization process under development by the US Department of Energy. Scaleup and design of this waste glass melting furnace requires an understanding of the relationships between melting cavity design parameters and the furnace performance characteristics such as mixing, heat transfer, and electrical requirements. Developing empirical models of these relationships through actual melter testing with numerous designs would be a very costly and time consuming task. Additionally, the Pacific Northwest Laboratory (PNL) has been developing numerical models that simulate a Joule-heated melter for analyzing melter performance. This report documents the method used and results of this modeling effort. Numerical modeling results are compared with the more conventional, physical modeling results to validate the approach. Also included are the results of numerically simulating an operating research melter at PNL. Physical Joule-heated melters modeling results used for qualiying the simulation capabilities of the melter code included: (1) a melter with a single pair of electrodes and (2) a melter with a dual pair (two pairs) of electrodes. The physical model of the melter having two electrode pairs utilized a configuration with primary and secondary electrodes. The principal melter parameters (the ratio of power applied to each electrode pair, modeling fluid depth, electrode spacing) were varied in nine tests of the physical model during FY85. Code predictions were made for five of these tests. Voltage drops, temperature field data, and electric field data varied in their agreement with the physical modeling results, but in general were judged acceptable. 14 refs., 79 figs., 17 tabs.

  8. Mathematical modeling and physical reality in noncovalent interactions.

    PubMed

    Politzer, Peter; Murray, Jane S; Clark, Timothy

    2015-03-01

    The Hellmann-Feynman theorem provides a straightforward interpretation of noncovalent bonding in terms of Coulombic interactions, which encompass polarization (and accordingly include dispersion). Exchange, Pauli repulsion, orbitals, etc., are part of the mathematics of obtaining the system's wave function and subsequently its electronic density. They do not correspond to physical forces. Charge transfer, in the context of noncovalent interactions, is equivalent to polarization. The key point is that mathematical models must not be confused with physical reality. PMID:25697332

  9. Physically representative atomistic modeling of atomic-scale friction

    NASA Astrophysics Data System (ADS)

    Dong, Yalin

    Nanotribology is a research field to study friction, adhesion, wear and lubrication occurred between two sliding interfaces at nano scale. This study is motivated by the demanding need of miniaturization mechanical components in Micro Electro Mechanical Systems (MEMS), improvement of durability in magnetic storage system, and other industrial applications. Overcoming tribological failure and finding ways to control friction at small scale have become keys to commercialize MEMS with sliding components as well as to stimulate the technological innovation associated with the development of MEMS. In addition to the industrial applications, such research is also scientifically fascinating because it opens a door to understand macroscopic friction from the most bottom atomic level, and therefore serves as a bridge between science and engineering. This thesis focuses on solid/solid atomic friction and its associated energy dissipation through theoretical analysis, atomistic simulation, transition state theory, and close collaboration with experimentalists. Reduced-order models have many advantages for its simplification and capacity to simulating long-time event. We will apply Prandtl-Tomlinson models and their extensions to interpret dry atomic-scale friction. We begin with the fundamental equations and build on them step-by-step from the simple quasistatic one-spring, one-mass model for predicting transitions between friction regimes to the two-dimensional and multi-atom models for describing the effect of contact area. Theoretical analysis, numerical implementation, and predicted physical phenomena are all discussed. In the process, we demonstrate the significant potential for this approach to yield new fundamental understanding of atomic-scale friction. Atomistic modeling can never be overemphasized in the investigation of atomic friction, in which each single atom could play a significant role, but is hard to be captured experimentally. In atomic friction, the

  10. A physical data model for fields and agents

    NASA Astrophysics Data System (ADS)

    de Jong, Kor; de Bakker, Merijn; Karssenberg, Derek

    2016-04-01

    Two approaches exist in simulation modeling: agent-based and field-based modeling. In agent-based (or individual-based) simulation modeling, the entities representing the system's state are represented by objects, which are bounded in space and time. Individual objects, like an animal, a house, or a more abstract entity like a country's economy, have properties representing their state. In an agent-based model this state is manipulated. In field-based modeling, the entities representing the system's state are represented by fields. Fields capture the state of a continuous property within a spatial extent, examples of which are elevation, atmospheric pressure, and water flow velocity. With respect to the technology used to create these models, the domains of agent-based and field-based modeling have often been separate worlds. In environmental modeling, widely used logical data models include feature data models for point, line and polygon objects, and the raster data model for fields. Simulation models are often either agent-based or field-based, even though the modeled system might contain both entities that are better represented by individuals and entities that are better represented by fields. We think that the reason for this dichotomy in kinds of models might be that the traditional object and field data models underlying those models are relatively low level. We have developed a higher level conceptual data model for representing both non-spatial and spatial objects, and spatial fields (De Bakker et al. 2016). Based on this conceptual data model we designed a logical and physical data model for representing many kinds of data, including the kinds used in earth system modeling (e.g. hydrological and ecological models). The goal of this work is to be able to create high level code and tools for the creation of models in which entities are representable by both objects and fields. Our conceptual data model is capable of representing the traditional feature data

  11. Female role models in physics education in Ireland

    NASA Astrophysics Data System (ADS)

    Chormaic, Síle Nic; Fee, Sandra; Tobin, Laura; Hennessy, Tara

    2013-03-01

    In this paper we consider the statistics on undergraduate student representation in Irish universities and look at student numbers in secondary (high) schools in one region in Ireland. There seems to be no significant change in female participation in physics from 2002 to 2011. Additionally, we have studied the influence of an educator's gender on the prevalence of girls studying physics in secondary schools in Co. Louth, Ireland, and at the postgraduate level in Irish universities. It would appear that strong female role models have a positive influence and lead to an increase in girls' participation in physics.

  12. Numerical investigation of the seismo-acoustic responses of the Source Physics Experiment underground explosions

    NASA Astrophysics Data System (ADS)

    Antoun, T.; Ezzedine, S. M.; Vorobiev, O.; Glenn, L. A.

    2015-12-01

    We have performed three-dimensional high resolution simulations of underground explosions conducted recently in jointed rock outcrop as part of the Source Physics Experiment (SPE) being conducted at the Nevada National Security Site (NNSS). The main goal of the current study is to investigate the effects of the structural and geomechanical properties on the spall phenomena due to underground explosions and its subsequent effect on the seismo-acoustic signature at far distances. Two parametric studies have been undertaken to assess the impact of different 1) conceptual geological models including a single layer and two layers model, with and without joints and with and without varying geomechanical properties, and 2) depth of bursts of the explosions and explosion yields. Through these investigations we have explored not only the near-field response of the explosions but also the far-field responses of the seismic and the acoustic signatures. The near-field simulations were conducted using the Eulerian and Lagrangian codes, GEODYN and GEODYN -L, respectively, while the far-field seismic simulations were conducted using the elastic wave propagation code, WPP, and the acoustic response using the Kirchhoff-Helmholtz-Rayleigh time-dependent approximation code, KHR. Though a series of simulations, we have recorded the velocity field histories a) at the ground surface on an acoustic-source-patch for the acoustic simulations, and 2) on a seismic-source-box for the seismic simulations. We first analyzed the SPE3 and SPE4-prime experimental data and simulated results, and then simulated SPE5, SPE6/7 to anticipate their seismo-acoustic responses given conditions of uncertainties. SPE experiments were conducted in a granitic formation; we have extended the parametric study to include other geological settings such dolomite and alluvial formations. These parametric studies enabled us 1) investigating the geotechnical and geophysical key parameters that impact the seismo

  13. Source signature and acoustic field of seismic physical modeling

    NASA Astrophysics Data System (ADS)

    Lin, Q.; Jackson, C.; Tang, G.; Burbach, G.

    2004-12-01

    As an important tool of seismic research and exploration, seismic physical modeling simulates the real world data acquisition by scaling the model, acquisition parameters, and some features of the source generated by a transducer. Unlike the numerical simulation where a point source is easily satisfied, the transducer can't be made small enough for approximating the point source in physical modeling, therefore yield different source signature than the sources applied in the field data acquisition. To better understand the physical modeling data, characterizing the wave field generated by ultrasonic transducers is desirable and helpful. In this study, we explode several aspects of source characterization; including their radiation pattern, directivity, sensitivity and frequency response. We also try to figure out how to improve the acquired data quality, such as minimize ambient noise, use encoded chirp to prevent ringing, apply deterministic deconvolution to enhance data resolution and t-P filtering to remove linear events. We found that the transducer and their wave field, the modeling system performance, as well as material properties of the model and their coupling conditions all play roles in the physical modeling data acquisition.

  14. A Goddard Multi-Scale Modeling System with Unified Physics

    NASA Technical Reports Server (NTRS)

    Tao, W.K.; Anderson, D.; Atlas, R.; Chern, J.; Houser, P.; Hou, A.; Lang, S.; Lau, W.; Peters-Lidard, C.; Kakar, R.; Kumar, S.; Lapenta, W.; Li, X.; Matsui, T.; Rienecker, M.; Shen, B.W.; Shi, J.J.; Simpson, J.; Zeng, X.

    2008-01-01

    Numerical cloud resolving models (CRMs), which are based the non-hydrostatic equations of motion, have been extensively applied to cloud-scale and mesoscale processes during the past four decades. Recent GEWEX Cloud System Study (GCSS) model comparison projects have indicated that CRMs agree with observations in simulating various types of clouds and cloud systems from different geographic locations. Cloud resolving models now provide statistical information useful for developing more realistic physically based parameterizations for climate models and numerical weather prediction models. It is also expected that Numerical Weather Prediction (NWP) and regional scale model can be run in grid size similar to cloud resolving model through nesting technique. Current and future NASA satellite programs can provide cloud, precipitation, aerosol and other data at very fine spatial and temporal scales. It requires a coupled global circulation model (GCM) and cloud-scale model (termed a szrper-parameterization or multi-scale modeling -framework, MMF) to use these satellite data to improve the understanding of the physical processes that are responsible for the variation in global and regional climate and hydrological systems. The use of a GCM will enable global coverage, and the use of a CRM will allow for better and more sophisticated physical parameterization. NASA satellite and field campaign can provide initial conditions as well as validation through utilizing the Earth Satellite simulators. At Goddard, we have developed a multi-scale modeling system with unified physics. The modeling system consists a coupled GCM-CRM (or MMF); a state-of-the-art weather research forecast model (WRF) and a cloud-resolving model (Goddard Cumulus Ensemble model). In these models, the same microphysical schemes (2ICE, several 3ICE), radiation (including explicitly calculated cloud optical properties), and surface models are applied. In addition, a comprehensive unified Earth Satellite

  15. An investigation into field effects of consciousness from the perspectives of Maharishi's Vedic Science and physics

    NASA Astrophysics Data System (ADS)

    Kleinschnitz, Kurt Warren

    1997-05-01

    A long-range field effect of consciousness has been reported repeatedly in the scientific literature over the past twenty years. This phenomenon is called the Maharishi Effect, after Maharishi Mahesh Yogi, the first to predict it. The Maharishi Effect is the phenomenon of improved societal trends resulting from the practice of the Transcendental Meditationoler program or group practice of the TM-Sidhioler program by a small fraction of a population. The Maharishi Effect is fundamentally a phenomenon of radiation of evolutionary influence arising from the enlivenment of pure consciousness, the unified field of natural law, in the perspective of Maharishi's Vedic Science. This perspective is corroborated by forty-three published or presented papers reporting on results of Maharishi Effect interventions world-wide at city, national, international, and global scales. Present day standard- model physics and physiology do not account for the outcomes of the research on the Maharishi Effect. Because the observed societal impact of the Maharishi Effect influence must be based in an impact on the individual, and investigators report detection of the effect in individual physiological measurements, a simple robust indicator for the effect might aid physiologists and physicists in the effort to extend their sciences to include such field effects of consciousness. Thus, this dissertation reports on two experiments investigating simple, robust, objective indicators for the effect. The dissertation concludes on a practical note with a description of the promise, available through concerted utilization of the knowledge and technologies of consciousness in Maharishi's Vedic Science, for enhanced national and global security in the face of unprecedented nuclear, biological, and genetic threats for which the modern sciences offer few sensible solutions. ftnolerTranscendental Meditation and TM-Sidhi are service marks registered in the United States Patent and Trademark Office

  16. Deciphering the Physical Basis of Biomineralization through Investigations of Nanoscale Growth Processes

    NASA Astrophysics Data System (ADS)

    Dove, P. M.; Davis, K. J.; De Yoreo, J. J.; Orme, C. A.

    2001-12-01

    Microbes and higher organisms direct the formation of complex structures in controlled biomineralization. Using biologically mediated crystallization strategies that have evolved over millenia, organisms have developed the ability to produce nanophase structures as single crystals and composite materials with remarkable properties that fulfill specific functional needs. Modern organisms, as well as those found in the sediment and rock records, chronicle Nature's ability to synthesize sophisticated nanostructures. Although biomineral compositions and their morphologies are windows to interpreting environments of prosperity and decline, most current interpretations lack an understanding of fundamental processes. Hence, the physical basis of biological mineralization continues as one of Nature's best kept secrets. Recently, the biomineralization processes of marine microorganisms have emerged as particularly important owing to the use of biomineral products as paleoclimate indicators. Besides providing critical information on crystal growth history, the minor and trace elements found in these materials also behave as impurities to regulate their properties and formation rates. Using integrated approaches, we are investigating the kinetics and thermodynamics of calcite growth to decipher mechanisms of biomineral formation. Our focus is to link molecular interactions with surface processes and nanoscale controls on crystal morphology. The molecular-scale structure of the crystalline interface is a critical growth determinant, especially when considering nanocrystalline phases. By combining in situ AFM studies of growth that use carefully characterized solution chemistries with molecular modeling and surface spectroscopic investigations, we couple observations of nanoscale growth mechanisms with quantitative kinetic and thermodynamic information. This approach is showing how key inorganic growth impurities, Mg2+ and Sr2+, affect mineralization through complex ion

  17. Retrospective examination of injuries and physical fitness during Federal Bureau of Investigation new agent training

    PubMed Central

    2011-01-01

    Background A retrospective examination was conducted of injuries, physical fitness, and their association among Federal Bureau of Investigation (FBI) new agent trainees. Methods Injuries and activities associated with injuries were obtained from a review of medical records in the medical clinic that served the new agents. A physical fitness test (PFT) was administered at Weeks 1, 7 and 14 of the 17-week new agent training course. The PFT consisted of push-ups, sit-ups, pull-ups, a 300-meter sprint, and a 1.5-mile run. Injury data were available from 2000 to 2008 and fitness data were available from 2004 to early 2009. Results During the survey period, 37% of men and 44% of women experienced one or more injuries during the new agent training course (risk ratio (women/men) = 1.18, 95% confidence interval = 1.07-1.31). The most common injury diagnoses were musculoskeletal pain (not otherwise specified) (27%), strains (11%), sprains (10%), contusions (9%), and abrasions/lacerations (9%). Activities associated with injury included defensive tactics training (48%), physical fitness training (26%), physical fitness testing (6%), and firearms training (6%). Over a 6-year period, there was little difference in performance of push-ups, sit-ups, pull-ups, or the 300-meter sprint; 1.5-mile run performance was higher in recent years. Among both men and women, higher injury incidence was associated with lower performance on any of the physical fitness measures. Conclusion This investigation documented injury diagnoses, activities associated with injury, and changes in physical fitness, and demonstrated that higher levels of physical fitness were associated with lower injury risk. PMID:21981817

  18. Messages on Flavour Physics Beyond the Standard Model

    NASA Astrophysics Data System (ADS)

    Buras, Andrzej J.

    2008-12-01

    We present a brief summary of the main results on flavour physics beyond the Standard Model that have been obtained in 2008 by my collaborators and myself in my group at TUM. In particular we list main messages coming from our analyses of flavour and CP-violating processes in Supersymmetry, Littlest Higgs model with T-Parity and a warped extra dimension model with custodial protection for the flavour diagonal and non-diagonal Z boson couplings.

  19. Macrocomposite mechanical design, modeling, and behavior of physical models of bioinspired fish armor

    NASA Astrophysics Data System (ADS)

    Browning, Ashley; Ortiz, Christine; Boyce, Mary C.

    2012-02-01

    The macrocomposite design of flexible biological exoskeletons, consisting of overlapping mineralized armor units embedded in a compliant tissue, is a key determinant of their mechanical function (e.g penetration resistance and biomechanical flexibility). Here, we investigate the role of macrocomposite structure, composition, geometric orientation, and spatial distribution in a flexible model natural armor system present in the majority of teleost fish species. Physical multi-material composite models are fabricated using a combination of 3-D printing and molding methods. Mechanical experiments using digital image correlation enable measurement of both the macroscopic response and underlying deformation mechanisms during various loading scenarios. Finite element-based mechanical models yield detailed insights into the roles and the tradeoffs of the composite structure providing constraint, shear, and bending mechanisms to impart protection and flexibility.

  20. Investigating Nitrogen Pollution: Activities and Models.

    ERIC Educational Resources Information Center

    Green Teacher, 2000

    2000-01-01

    Introduces activities on nitrogen, nitrogen pollution from school commuters, nitrogen response in native and introduced species, and nutrient loading models. These activities help students determine the nitrogen contribution from their parents' cars, test native plant responses to nitrogen, and experiment with the results of removing water from…

  1. Investigating Population Heterogeneity With Factor Mixture Models

    ERIC Educational Resources Information Center

    Lubke, Gitta H.; Muthen, Bengt

    2005-01-01

    Sources of population heterogeneity may or may not be observed. If the sources of heterogeneity are observed (e.g., gender), the sample can be split into groups and the data analyzed with methods for multiple groups. If the sources of population heterogeneity are unobserved, the data can be analyzed with latent class models. Factor mixture models…

  2. Investigating the Effect of Damage Progression Model Choice on Prognostics Performance

    NASA Technical Reports Server (NTRS)

    Daigle, Matthew; Roychoudhury, Indranil; Narasimhan, Sriram; Saha, Sankalita; Saha, Bhaskar; Goebel, Kai

    2011-01-01

    The success of model-based approaches to systems health management depends largely on the quality of the underlying models. In model-based prognostics, it is especially the quality of the damage progression models, i.e., the models describing how damage evolves as the system operates, that determines the accuracy and precision of remaining useful life predictions. Several common forms of these models are generally assumed in the literature, but are often not supported by physical evidence or physics-based analysis. In this paper, using a centrifugal pump as a case study, we develop different damage progression models. In simulation, we investigate how model changes influence prognostics performance. Results demonstrate that, in some cases, simple damage progression models are sufficient. But, in general, the results show a clear need for damage progression models that are accurate over long time horizons under varied loading conditions.

  3. Reading Time as Evidence for Mental Models in Understanding Physics

    NASA Astrophysics Data System (ADS)

    Brookes, David T.; Mestre, José; Stine-Morrow, Elizabeth A. L.

    2007-11-01

    We present results of a reading study that show the usefulness of probing physics students' cognitive processing by measuring reading time. According to contemporary discourse theory, when people read a text, a network of associated inferences is activated to create a mental model. If the reader encounters an idea in the text that conflicts with existing knowledge, the construction of a coherent mental model is disrupted and reading times are prolonged, as measured using a simple self-paced reading paradigm. We used this effect to study how "non-Newtonian" and "Newtonian" students create mental models of conceptual systems in physics as they read texts related to the ideas of Newton's third law, energy, and momentum. We found significant effects of prior knowledge state on patterns of reading time, suggesting that students attempt to actively integrate physics texts with their existing knowledge.

  4. Transport in Polymer-Electrolyte Membranes I. Physical Model

    SciTech Connect

    Weber, Adam Z.; Newman, John

    2003-06-02

    In this paper, a physical model is developed that is semiphenomenological and takes into account Schroeder's paradox. Using the wealth of knowledge contained in the literature regarding polymer-electrolyte membranes as a basis, a novel approach is taken in tying together all of the data into a single coherent theory. This approach involves describing the structural changes of the membrane due to water content, and casting this in terms of capillary phenomena. By treating the membrane in this fashion, Schroeder's paradox can be elucidated. Along with the structural changes, two different transport mechanisms are presented and discussed. These mechanisms, along with the membrane's structural changes, comprise the complete physical model of the membrane. The model is shown to agree qualitatively with different membranes and different membrane forms, and is applicable to modeling perfluorinated sulfonic acid and similar membranes. It is also the first physically based comprehensive model of transport in a membrane that includes a physical description of Schroeder's paradox, and it bridges the gap between the two types of macroscopic models currently in the literature.

  5. Investigating diet and physical activity in Malaysia: education and family history of diabetes relate to lower levels of physical activity

    PubMed Central

    Tam, Cai Lian; Bonn, Gregory; Yeoh, Si Han; Wong, Chee Piau

    2014-01-01

    The National Health and Morbidity Survey (NHMS, 2011), estimates that the number of Malaysian adults suffering from type 2 diabetes has increased from 8.3 to 31.2% since 1996. This study is a preliminary investigation of possible factors contributing to this epidemic. Knowledge of diabetes, health locus of control, diet and exercise habits, as well as family history, education level and other demographic factors to better understand the correlates of risky and healthy behaviors. This was done as part of a larger initiative to improve prevention efforts. Questionnaires were completed by 770 individuals from three Malaysian states: Selangor, Penang, and Terengganu. Findings showed that people with better health knowledge and those who have a family history of type 2 diabetes were more likely to have healthy diets. Also, health knowledge related to lower alcohol consumption. Participants with diabetic family members, however, also reported higher levels of stress. Counterintuitively, higher educational levels, higher internal locus of control, better health knowledge, as well as a family history of diabetes all correlated with lower levels of physical activity. Thus, it is suggested that, while increasing health knowledge will be important in addressing the type 2 diabetes epidemic in Malaysia, especially in relation to diet, other cultural factors, specifically norms related to exercise and physical activity, also need to be addressed if the spread of type 2 diabetes is to be addressed over the long term. PMID:25520676

  6. Investigating diet and physical activity in Malaysia: education and family history of diabetes relate to lower levels of physical activity.

    PubMed

    Tam, Cai Lian; Bonn, Gregory; Yeoh, Si Han; Wong, Chee Piau

    2014-01-01

    The National Health and Morbidity Survey (NHMS, 2011), estimates that the number of Malaysian adults suffering from type 2 diabetes has increased from 8.3 to 31.2% since 1996. This study is a preliminary investigation of possible factors contributing to this epidemic. Knowledge of diabetes, health locus of control, diet and exercise habits, as well as family history, education level and other demographic factors to better understand the correlates of risky and healthy behaviors. This was done as part of a larger initiative to improve prevention efforts. Questionnaires were completed by 770 individuals from three Malaysian states: Selangor, Penang, and Terengganu. Findings showed that people with better health knowledge and those who have a family history of type 2 diabetes were more likely to have healthy diets. Also, health knowledge related to lower alcohol consumption. Participants with diabetic family members, however, also reported higher levels of stress. Counterintuitively, higher educational levels, higher internal locus of control, better health knowledge, as well as a family history of diabetes all correlated with lower levels of physical activity. Thus, it is suggested that, while increasing health knowledge will be important in addressing the type 2 diabetes epidemic in Malaysia, especially in relation to diet, other cultural factors, specifically norms related to exercise and physical activity, also need to be addressed if the spread of type 2 diabetes is to be addressed over the long term.

  7. Combined physical and chemical nonequilibrium transport model for solution conduits

    NASA Astrophysics Data System (ADS)

    Field, Malcolm S.; Leij, Feike J.

    2014-02-01

    Solute transport in karst aquifers is primarily constrained to relatively complex and inaccessible solution conduits where transport is often rapid, turbulent, and at times constrictive. Breakthrough curves generated from tracer tests in solution conduits are typically positively-skewed with long tails evident. Physical nonequilibrium models to fit breakthrough curves for tracer tests in solution conduits are now routinely employed. Chemical nonequilibrium processes are likely important interactions, however. In addition to partitioning between different flow domains, there may also be equilibrium and nonequilibrium partitioning between the aqueous and solid phases. A combined physical and chemical nonequilibrium (PCNE) model was developed for an instantaneous release similar to that developed by Leij and Bradford (2009) for a pulse release. The PCNE model allows for partitioning open space in solution conduits into mobile and immobile flow regions with first-order mass transfer between the two regions to represent physical nonequilibrium in the conduit. Partitioning between the aqueous and solid phases proceeds either as an equilibrium process or as a first-order process and represents chemical nonequilibrium for both the mobile and immobile regions. Application of the model to three example breakthrough curves demonstrates the applicability of the combined physical and chemical nonequilibrium model to tracer tests conducted in karst aquifers, with exceptionally good model fits to the data. The three models, each from a different state in the United States, exhibit very different velocities, dispersions, and other transport properties with most of the transport occurring via the fraction of mobile water. Fitting the model suggests the potentially important interaction of physical and chemical nonequilibrium processes.

  8. A physics based investigation of Gurney flaps for enhancement of rotorcraft flight characteristics

    NASA Astrophysics Data System (ADS)

    Min, Byung-Young

    Helicopters are versatile vehicles that can vertically take off and land, hover, and perform maneuver at very low forward speeds. These characteristics make them unique for a number of civilian and military applications. However, the radial and azimuthal variation of dynamic pressure causes rotors to experience adverse phenomena such as transonic shocks and 3-D dynamic stall. Adverse interactions such as blade vortex interaction and rotor-airframe interaction may also occur. These phenomena contribute to noise and vibrations. Finally, in the event of an engine failure, rotorcraft tends to descend at high vertical velocities causing structural damage and loss of lives. A variety of techniques have been proposed for reducing the noise and vibrations. These techniques include on-board control (OBC) devices, individual blade control (IBC), and higher harmonic control (HHC). Addition of these devices adds to the weight, cost, and complexity of the rotor system, and reduces the reliability of operations. Simpler OBC concepts will greatly alleviate these drawbacks and enhance the operating envelope of vehicles. In this study, the use of Gurney flaps is explored as an OBC concept using a physics based approach. A three dimensional Navier-Stokes solver developed by the present investigator is coupled to an existing free wake model of the wake structure. The method is further enhanced for modeling of Blade-Vortex-Interactions (BVI). Loose coupling with an existing comprehensive structural dynamics analysis solver (DYMORE) is implemented for the purpose of rotor trim and modeling of aeroelastic effects. Results are presented for Gurney flaps as an OBC concept for improvements in autorotation, rotor vibration reduction, and BVI characteristics. As a representative rotor, the HART-II model rotor is used. It is found that the Gurney flap increases propulsive force in the driving region while the drag force is increased in the driven region. It is concluded that the deployable

  9. A mathematical look at a physical power prediction model

    SciTech Connect

    Landberg, L.

    1997-12-31

    This paper takes a mathematical look at a physical model used to predict the power produced from wind farms. The reason is to see whether simple mathematical expressions can replace the original equations, and to give guidelines as to where the simplifications can be made and where they can not. This paper shows that there is a linear dependence between the geostrophic wind and the wind at the surface, but also that great care must be taken in the selection of the models since physical dependencies play a very important role, e.g. through the dependence of the turning of the wind on the wind speed.

  10. Physics-based model for electro-chemical process

    SciTech Connect

    Zhang, Jinsuo

    2013-07-01

    Considering the kinetics of electrochemical reactions and mass transfer at the surface and near-surface of the electrode, a physics-based separation model for separating actinides from fission products in an electro-refiner is developed. The model, taking into account the physical, chemical and electrochemical processes at the electrode surface, can be applied to study electrorefining kinetics. One of the methods used for validation has been to apply the developed model to the computation of the cyclic voltammetry process of PuCl{sub 3} and UCl{sub 3} at a solid electrode in molten KCl-LiCl. The computed results appear to be similar to experimental measures. The separation model can be applied to predict materials flows under normal and abnormal operation conditions. Parametric studies can be conducted based on the model to identify the most important factors that affect the electrorefining processes.

  11. Highly physical penumbra solar radiation pressure modeling with atmospheric effects

    NASA Astrophysics Data System (ADS)

    Robertson, Robert; Flury, Jakob; Bandikova, Tamara; Schilling, Manuel

    2015-10-01

    We present a new method for highly physical solar radiation pressure (SRP) modeling in Earth's penumbra. The fundamental geometry and approach mirrors past work, where the solar radiation field is modeled using a number of light rays, rather than treating the Sun as a single point source. However, we aim to clarify this approach, simplify its implementation, and model previously overlooked factors. The complex geometries involved in modeling penumbra solar radiation fields are described in a more intuitive and complete way to simplify implementation. Atmospheric effects are tabulated to significantly reduce computational cost. We present new, more efficient and accurate approaches to modeling atmospheric effects which allow us to consider the high spatial and temporal variability in lower atmospheric conditions. Modeled penumbra SRP accelerations for the Gravity Recovery and Climate Experiment (GRACE) satellites are compared to the sub-nm/s2 precision GRACE accelerometer data. Comparisons to accelerometer data and a traditional penumbra SRP model illustrate the improved accuracy which our methods provide. Sensitivity analyses illustrate the significance of various atmospheric parameters and modeled effects on penumbra SRP. While this model is more complex than a traditional penumbra SRP model, we demonstrate its utility and propose that a highly physical model which considers atmospheric effects should be the basis for any simplified approach to penumbra SRP modeling.

  12. Physics-based simulation models for EBSD: advances and challenges

    NASA Astrophysics Data System (ADS)

    Winkelmann, A.; Nolze, G.; Vos, M.; Salvat-Pujol, F.; Werner, W. S. M.

    2016-02-01

    EBSD has evolved into an effective tool for microstructure investigations in the scanning electron microscope. The purpose of this contribution is to give an overview of various simulation approaches for EBSD Kikuchi patterns and to discuss some of the underlying physical mechanisms.

  13. Investigating habits: strategies, technologies and models

    PubMed Central

    Smith, Kyle S.; Graybiel, Ann M.

    2014-01-01

    Understanding habits at a biological level requires a combination of behavioral observations and measures of ongoing neural activity. Theoretical frameworks as well as definitions of habitual behaviors emerging from classic behavioral research have been enriched by new approaches taking account of the identification of brain regions and circuits related to habitual behavior. Together, this combination of experimental and theoretical work has provided key insights into how brain circuits underlying action-learning and action-selection are organized, and how a balance between behavioral flexibility and fixity is achieved. New methods to monitor and manipulate neural activity in real time are allowing us to have a first look “under the hood” of a habit as it is formed and expressed. Here we discuss ideas emerging from such approaches. We pay special attention to the unexpected findings that have arisen from our own experiments suggesting that habitual behaviors likely require the simultaneous activity of multiple distinct components, or operators, seen as responsible for the contrasting dynamics of neural activity in both cortico-limbic and sensorimotor circuits recorded concurrently during different stages of habit learning. The neural dynamics identified thus far do not fully meet expectations derived from traditional models of the structure of habits, and the behavioral measures of habits that we have made also are not fully aligned with these models. We explore these new clues as opportunities to refine an understanding of habits. PMID:24574988

  14. Validation of the physical modeling approach for braided rivers

    NASA Astrophysics Data System (ADS)

    Rosatti, Giorgio

    2002-12-01

    Laboratory channels are often used to study the complexity of braiding mechanisms for the advantages with respect to field studies. Nevertheless, the extensive use of experimental data raises the question of how representative laboratory braided channels are as compared to real braided rivers. This study verifies to what extent laboratory braided patterns reproduce the main features of braided rivers. Experimental data display isotropic and anisotropic scaling of braided patterns, state-space plot of total widths, anisotropic scaling of islands, and statistical distribution of island areas that are similar to those observed in real rivers. Moreover, the data reveals scaling in the perimeter-area relation. These results support both the reliability of experimental braided channels as physical models of braided rivers and also the possibility of investigating some aspects of braiding in the laboratory that are difficult to address in the field. The lack of preferential scales in island characteristics suggests that other phenomena must play a key role in generating island shapes besides classical sediment transport-based mechanisms which tend to select well-defined length scales.

  15. Developing physical frailty specifications for investigation of frailty pathways in older people.

    PubMed

    Ding, Yew Y

    2016-04-01

    Different frailty definitions are suitable for different purposes. When investigating its key multidimensional predictors and effects, narrower definitions of frailty that exclude these elements may be more desirable. For this purpose, candidate physical frailty specifications are constructed and then evaluated on their construct and concurrent validity. For 4638 participants aged 65 to 89 years from wave 2 (2004) of the English Longitudinal Study of Ageing, confirmatory factor analysis is performed to create physical frailty specifications with four indicators (slowness, weakness, exhaustion, and weight loss) and with three indicators (slowness, weakness, and either exhaustion or weight loss). Using derived factor scores, their convergent, discriminant, and concurrent validity are compared. For specifications with four indicators and with three indicators including exhaustion, slowness contributes dominantly to the physical frailty factor. However, with three indicators including weight loss, weakness contributes most. Where represented, weight loss only contributes minimally. Higher factor scores are significantly associated with chronic diseases, functional impairment, and poor self-rated health, although less so for the third specification. Factor scores for the first two specifications have low correlation with psychological and social frailty while those for the third have negligible correlation. Factor scores increase with higher Frailty Index although again less so for the third specification. Minor differences are seen across gender. On account of their convergent, discriminatory, and concurrent validity, physical frailty specifications with four indicators and with three indicators including exhaustion hold promise for use in investigation of frailty pathways involving multidimensional predictors and effects. PMID:27059656

  16. Loop quantum cosmology in Bianchi type I models: Analytical investigation

    SciTech Connect

    Chiou, D.-W.

    2007-01-15

    The comprehensive formulation for loop quantum cosmology in the spatially flat, isotropic model was recently constructed. In this paper, the methods are extended to the anisotropic Bianchi I cosmology. Both the precursor and the improved strategies are applied and the expected results are established: (i) the scalar field again serves as an internal clock and is treated as emergent time; (ii) the total Hamiltonian constraint is derived by imposing the fundamental discreteness and gives the evolution as a difference equation; and (iii) the physical Hilbert space, Dirac observables, and semiclassical states are constructed rigorously. It is also shown that the state in the kinematical Hilbert space associated with the classical singularity is decoupled in the difference evolution equation, indicating that the big bounce may take place when any of the area scales undergoes the vanishing behavior. The investigation affirms the robustness of the framework used in the isotropic model by enlarging its domain of validity and provides foundations to conduct the detailed numerical analysis.

  17. Cavitation erosion - scale effect and model investigations

    NASA Astrophysics Data System (ADS)

    Geiger, F.; Rutschmann, P.

    2015-12-01

    The experimental works presented in here contribute to the clarification of erosive effects of hydrodynamic cavitation. Comprehensive cavitation erosion test series were conducted for transient cloud cavitation in the shear layer of prismatic bodies. The erosion pattern and erosion rates were determined with a mineral based volume loss technique and with a metal based pit count system competitively. The results clarified the underlying scale effects and revealed a strong non-linear material dependency, which indicated significantly different damage processes for both material types. Furthermore, the size and dynamics of the cavitation clouds have been assessed by optical detection. The fluctuations of the cloud sizes showed a maximum value for those cavitation numbers related to maximum erosive aggressiveness. The finding suggests the suitability of a model approach which relates the erosion process to cavitation cloud dynamics. An enhanced experimental setup is projected to further clarify these issues.

  18. Geometric investigations of a vorticity model equation

    NASA Astrophysics Data System (ADS)

    Bauer, Martin; Kolev, Boris; Preston, Stephen C.

    2016-01-01

    This article consists of a detailed geometric study of the one-dimensional vorticity model equation which is a particular case of the generalized Constantin-Lax-Majda equation. Wunsch showed that this equation is the Euler-Arnold equation on Diff (S1) when the latter is endowed with the right-invariant homogeneous H ˙ 1 / 2-metric. In this article we prove that the exponential map of this Riemannian metric is not Fredholm and that the sectional curvature is locally unbounded. Furthermore, we prove a Beale-Kato-Majda-type blow-up criterion, which we then use to demonstrate a link to our non-Fredholmness result. Finally, we extend a blow-up result of Castro-Córdoba to the periodic case and to a much wider class of initial conditions, using a new generalization of an inequality for Hilbert transforms due to Córdoba-Córdoba.

  19. An Investigation of Item Fit Statistics for Mixed IRT Models

    ERIC Educational Resources Information Center

    Chon, Kyong Hee

    2009-01-01

    The purpose of this study was to investigate procedures for assessing model fit of IRT models for mixed format data. In this study, various IRT model combinations were fitted to data containing both dichotomous and polytomous item responses, and the suitability of the chosen model mixtures was evaluated based on a number of model fit procedures.…

  20. Coarse-grained, foldable, physical model of the polypeptide chain

    PubMed Central

    Chakraborty, Promita; Zuckermann, Ronald N.

    2013-01-01

    Although nonflexible, scaled molecular models like Pauling–Corey’s and its descendants have made significant contributions in structural biology research and pedagogy, recent technical advances in 3D printing and electronics make it possible to go one step further in designing physical models of biomacromolecules: to make them conformationally dynamic. We report here the design, construction, and validation of a flexible, scaled, physical model of the polypeptide chain, which accurately reproduces the bond rotational degrees of freedom in the peptide backbone. The coarse-grained backbone model consists of repeating amide and α-carbon units, connected by mechanical bonds (corresponding to φ and ψ) that include realistic barriers to rotation that closely approximate those found at the molecular scale. Longer-range hydrogen-bonding interactions are also incorporated, allowing the chain to readily fold into stable secondary structures. The model is easily constructed with readily obtainable parts and promises to be a tremendous educational aid to the intuitive understanding of chain folding as the basis for macromolecular structure. Furthermore, this physical model can serve as the basis for linking tangible biomacromolecular models directly to the vast array of existing computational tools to provide an enhanced and interactive human–computer interface. PMID:23898168

  1. Investigating children's spiritual experiences through the Health and Physical Education (HPE) learning area in Australian schools.

    PubMed

    Lynch, Timothy

    2015-02-01

    The purpose of this study is to explore spirituality within the Health and Physical Education (HPE) learning area, through investigating children's experiences within three Brisbane Catholic Education primary schools (Queensland, Australia). There are seven dimensions of wellness: physical, intellectual, emotional, social, spiritual, environmental, and occupational, which are all strongly connected (Robbins et al. in A wellness way of life, 9th edition, McGraw Hill, USA, 2011). It is logical that HPE, which promotes students to adopt lifelong health and well-being, offers opportunities for spirituality to be experienced and warrants investigation. Data gathered in this qualitative research suggest that regular quality inclusive HPE lessons increased students' potential for spiritual experiences. PMID:24306452

  2. Effectiveness of the Sport Education Fitness Model on Fitness Levels, Knowledge, and Physical Activity

    ERIC Educational Resources Information Center

    Pritchard, Tony; Hansen, Andrew; Scarboro, Shot; Melnic, Irina

    2015-01-01

    The purpose of this study was to investigate changes in fitness levels, content knowledge, physical activity levels, and participants' perceptions following the implementation of the sport education fitness model (SEFM) at a high school. Thirty-two high school students participated in 20 lessons using the SEFM. Aerobic capacity, muscular…

  3. Modeling the Stress Complexities of Teaching and Learning of School Physics in Nigeria

    ERIC Educational Resources Information Center

    Emetere, Moses E.

    2014-01-01

    This study was designed to investigate the validity of the stress complexity model (SCM) to teaching and learning of school physics in Abuja municipal area council of Abuja, North. About two hundred students were randomly selected by a simple random sampling technique from some schools within the Abuja municipal area council. A survey research…

  4. The Effectiveness of Physical Models in Teaching Anatomy: A Meta-Analysis of Comparative Studies

    ERIC Educational Resources Information Center

    Yammine, Kaissar; Violato, Claudio

    2016-01-01

    There are various educational methods used in anatomy teaching. While three dimensional (3D) visualization technologies are gaining ground due to their ever-increasing realism, reports investigating physical models as a low-cost 3D traditional method are still the subject of considerable interest. The aim of this meta-analysis is to quantitatively…

  5. Physical and Interpersonal Attractiveness of the Model and Imitation in Adults.

    ERIC Educational Resources Information Center

    Adams, Gerald R.; LaVoie, Joseph C.

    The effects of physical attractiveness, warmth, and sex of an adult model on imitation behavior of adult males and females were investigated. Subjects were randomly paired with confederates of low or high facial attractiveness who interacted with the subject in a cold-unfriendly or warm-friendly manner. The imitation task involved the confederate…

  6. The Implementation of Models-Based Practice in Physical Education through Action Research

    ERIC Educational Resources Information Center

    Casey, Ashley; Dyson, Ben

    2009-01-01

    The purpose of this study was to explore the use of action research as a framework to investigate cooperative learning and tactical games as instructional models in physical education (PE). The teacher/researcher taught a tennis unit using a combination of Cooperative Learning and Teaching Games for Understanding to three classes of boys aged…

  7. A comprehensive physics-based model encompassing variable surface resistance and underlying physics of ionic polymer-metal composite actuators

    NASA Astrophysics Data System (ADS)

    Shen, Qi; Palmre, Viljar; Stalbaum, Tyler; Kim, Kwang J.

    2015-09-01

    The ionic polymer-metal composite (IPMC) is an emerging smart material in actuation and sensing applications, such as artificial muscles, underwater actuators, and advanced medical devices. However, the effect of the change in surface electrode properties on the actuating of IPMC has not been well studied. To address this problem, we theoretically predict and experimentally investigate the dynamic electro-mechanical response of the IPMC thin-strip actuator. A model of the IPMC actuator is proposed based on the Poisson-Nernst-Planck equations for ion transport and charge dynamics in the polymer membrane, while a physical model for the change of surface resistance of the electrodes of the IPMC due to deformation is also incorporated. By incorporating these two models, a complete, dynamic, physics-based model for IPMC actuators is presented. To verify the model, IPMC samples were prepared and experiments were conducted. The results show that the theoretical model can accurately predict the actuating performance of IPMC actuators over a range of dynamic conditions. Additionally, the charge dynamics inside the polymer during the oscillation of the IPMC is presented. It is also shown that the charge at the boundary mainly affects the induced stress of the IPMC. The current study is beneficial for the comprehensive understanding of the surface electrode effect on the performance of IPMC actuators.

  8. Compressive sensing as a paradigm for building physics models

    NASA Astrophysics Data System (ADS)

    Nelson, Lance J.; Hart, Gus L. W.; Zhou, Fei; Ozoliņš, Vidvuds

    2013-01-01

    The widely accepted intuition that the important properties of solids are determined by a few key variables underpins many methods in physics. Though this reductionist paradigm is applicable in many physical problems, its utility can be limited because the intuition for identifying the key variables often does not exist or is difficult to develop. Machine learning algorithms (genetic programming, neural networks, Bayesian methods, etc.) attempt to eliminate the a priori need for such intuition but often do so with increased computational burden and human time. A recently developed technique in the field of signal processing, compressive sensing (CS), provides a simple, general, and efficient way of finding the key descriptive variables. CS is a powerful paradigm for model building; we show that its models are more physical and predict more accurately than current state-of-the-art approaches and can be constructed at a fraction of the computational cost and user effort.

  9. Progress in Geant4 Electromagnetic Physics Modelling and Validation

    NASA Astrophysics Data System (ADS)

    Apostolakis, J.; Asai, M.; Bagulya, A.; Brown, J. M. C.; Burkhardt, H.; Chikuma, N.; Cortes-Giraldo, M. A.; Elles, S.; Grichine, V.; Guatelli, S.; Incerti, S.; Ivanchenko, V. N.; Jacquemier, J.; Kadri, O.; Maire, M.; Pandola, L.; Sawkey, D.; Toshito, T.; Urban, L.; Yamashita, T.

    2015-12-01

    In this work we report on recent improvements in the electromagnetic (EM) physics models of Geant4 and new validations of EM physics. Improvements have been made in models of the photoelectric effect, Compton scattering, gamma conversion to electron and muon pairs, fluctuations of energy loss, multiple scattering, synchrotron radiation, and high energy positron annihilation. The results of these developments are included in the new Geant4 version 10.1 and in patches to previous versions 9.6 and 10.0 that are planned to be used for production for run-2 at LHC. The Geant4 validation suite for EM physics has been extended and new validation results are shown in this work. In particular, the effect of gamma-nuclear interactions on EM shower shape at LHC energies is discussed.

  10. Filamentous Phages As a Model System in Soft Matter Physics.

    PubMed

    Dogic, Zvonimir

    2016-01-01

    Filamentous phages have unique physical properties, such as uniform particle lengths, that are not found in other model systems of rod-like colloidal particles. Consequently, suspensions of such phages provided powerful model systems that have advanced our understanding of soft matter physics in general and liquid crystals in particular. We described some of these advances. In particular we briefly summarize how suspensions of filamentous phages have provided valuable insight into the field of colloidal liquid crystals. We also describe recent experiments on filamentous phages that have elucidated a robust pathway for assembly of 2D membrane-like materials. Finally, we outline unique structural properties of filamentous phages that have so far remained largely unexplored yet have the potential to further advance soft matter physics and material science. PMID:27446051

  11. An Introduction to the Standard Model of Particle Physics

    NASA Astrophysics Data System (ADS)

    Cottingham, W. Noel; Greenwood, Derek A.

    1999-01-01

    This graduate textbook provides a concise, accessible introduction to the Standard Model of particle physics. Theoretical concepts are developed clearly and carefully throughout the book--from the electromagnetic and weak interactions of leptons and quarks to the strong interactions of quarks. Chapters developing the theory are interspersed with chapters describing some of the wealth of experimental data supporting the model. The book assumes only the standard mathematics taught in an undergraduate physics course; more sophisticated mathematical ideas are developed in the text and in appendices. For graduate students in particle physics and physicists working in other fields who are interested in the current understanding of the ultimate constituents of matter, this textbook provides a lucid and up-to-date introduction.

  12. A stochastic physical system approach to modeling river water quality

    NASA Astrophysics Data System (ADS)

    Curi, W. F.; Unny, T. E.; Kay, J. J.

    1995-06-01

    In this paper, concepts of network thermodynamics are applied to a river water quality model, which is based on Streeter-Phelps equations, to identify the corresponding physical components and their topology. Then, the randomness in the parameters, input coefficients and initial conditions are modeled by Gaussian white noises. From the stochastic components of the physical system description of problem and concepts of physical system theory, a set of stochastic differential equations can be automatically generated in a computer and the recent developments on the automatic formulation of the moment equations based on Ito calculus can be used. This procedure is illustrated through the solution of an example of stochastic river water quality problem and it is also shown how other related problems with different configurations can be automatically solved in a computer using just one software.

  13. Filamentous Phages As a Model System in Soft Matter Physics.

    PubMed

    Dogic, Zvonimir

    2016-01-01

    Filamentous phages have unique physical properties, such as uniform particle lengths, that are not found in other model systems of rod-like colloidal particles. Consequently, suspensions of such phages provided powerful model systems that have advanced our understanding of soft matter physics in general and liquid crystals in particular. We described some of these advances. In particular we briefly summarize how suspensions of filamentous phages have provided valuable insight into the field of colloidal liquid crystals. We also describe recent experiments on filamentous phages that have elucidated a robust pathway for assembly of 2D membrane-like materials. Finally, we outline unique structural properties of filamentous phages that have so far remained largely unexplored yet have the potential to further advance soft matter physics and material science.

  14. Filamentous Phages As a Model System in Soft Matter Physics

    PubMed Central

    Dogic, Zvonimir

    2016-01-01

    Filamentous phages have unique physical properties, such as uniform particle lengths, that are not found in other model systems of rod-like colloidal particles. Consequently, suspensions of such phages provided powerful model systems that have advanced our understanding of soft matter physics in general and liquid crystals in particular. We described some of these advances. In particular we briefly summarize how suspensions of filamentous phages have provided valuable insight into the field of colloidal liquid crystals. We also describe recent experiments on filamentous phages that have elucidated a robust pathway for assembly of 2D membrane-like materials. Finally, we outline unique structural properties of filamentous phages that have so far remained largely unexplored yet have the potential to further advance soft matter physics and material science. PMID:27446051

  15. Towards gender equity in physics in India: Initiatives, investigations, and questions

    NASA Astrophysics Data System (ADS)

    Shastri, P.; Kurup, A.; Resmi, L.; Ramaswamy, R.; Ubale, S.; Bagchi, S.; Rao, S.; Narasimhan, S.

    2015-12-01

    Initiatives towards gender parity in the sciences in India have occurred both at national, governmental levels and at local, institutional levels. A gender gap persists in physics, but data suggest that this gap is due neither to lack of interest in science nor to a lack of career goals in science among girls. We outline investigations that are important to pursue and recommendations that build on the existing science interest and the impact of initiatives so far.

  16. An integrated numerical and physical modeling system for an enhanced in situ bioremediation process.

    PubMed

    Huang, Y F; Huang, G H; Wang, G Q; Lin, Q G; Chakma, A

    2006-12-01

    Groundwater contamination due to releases of petroleum products is a major environmental concern in many urban districts and industrial zones. Over the past years, a few studies were undertaken to address in situ bioremediation processes coupled with contaminant transport in two- or three-dimensional domains. However, they were concentrated on natural attenuation processes for petroleum contaminants or enhanced in situ bioremediation processes in laboratory columns. In this study, an integrated numerical and physical modeling system is developed for simulating an enhanced in situ biodegradation (EISB) process coupled with three-dimensional multiphase multicomponent flow and transport simulation in a multi-dimensional pilot-scale physical model. The designed pilot-scale physical model is effective in tackling natural attenuation and EISB processes for site remediation. The simulation results demonstrate that the developed system is effective in modeling the EISB process, and can thus be used for investigating the effects of various uncertainties.

  17. Scratch as a computational modelling tool for teaching physics

    NASA Astrophysics Data System (ADS)

    Lopez, Victor; Hernandez, Maria Isabel

    2015-05-01

    The Scratch online authoring tool, which features a simple programming language that has been adapted to primary and secondary students, is being used more and more in schools as it offers students and teachers the opportunity to use a tool to build scientific models and evaluate their behaviour, just as can be done with computational modelling programs. In this article, we briefly discuss why Scratch could be a useful tool for computational modelling in the primary or secondary physics classroom, and we present practical examples of how it can be used to build a model.

  18. A physics investigation of deadtime losses in neutron counting at low rates with Cf252

    SciTech Connect

    Evans, Louise G; Croft, Stephen

    2009-01-01

    {sup 252}Cf spontaneous fission sources are used for the characterization of neutron counters and the determination of calibration parameters; including both neutron coincidence counting (NCC) and neutron multiplicity deadtime (DT) parameters. Even at low event rates, temporally-correlated neutron counting using {sup 252}Cf suffers a deadtime effect. Meaning that in contrast to counting a random neutron source (e.g. AmLi to a close approximation), DT losses do not vanish in the low rate limit. This is because neutrons are emitted from spontaneous fission events in time-correlated 'bursts', and are detected over a short period commensurate with their lifetime in the detector (characterized by the system die-away time, {tau}). Thus, even when detected neutron events from different spontaneous fissions are unlikely to overlap in time, neutron events within the detected 'burst' are subject to intrinsic DT losses. Intrinsic DT losses for dilute Pu will be lower since the multiplicity distribution is softer, but real items also experience self-multiplication which can increase the 'size' of the bursts. Traditional NCC DT correction methods do not include the intrinsic (within burst) losses. We have proposed new forms of the traditional NCC Singles and Doubles DT correction factors. In this work, we apply Monte Carlo neutron pulse train analysis to investigate the functional form of the deadtime correction factors for an updating deadtime. Modeling is based on a high efficiency {sup 3}He neutron counter with short die-away time, representing an ideal {sup 3}He based detection system. The physics of dead time losses at low rates is explored and presented. It is observed that new forms are applicable and offer more accurate correction than the traditional forms.

  19. Theoretical investigations of the physical properties of zircon-type YVO{sub 4}

    SciTech Connect

    Huang Zuocai; Feng Jing; Pan Wei

    2012-01-15

    The crystal structure, electronic properties, elastic properties, hardness and thermodynamic properties of the laser host material zircon-type YVO{sub 4} are studied using the pseudopotential plane wave method within the local density approximation (LDA) and generalized gradient approximation (GGA). The calculated ground state values such as lattice parameter, bulk modulus and its pressure derivative, the band structure and densities of states were in favorable agreement with previous works and the existed experimental data. The elastic constants C{sub ij}, the aggregate elastic moduli (B, G, E), Poisson's ratio and elastic anisotropy have been investigated. In YVO{sub 4}, V-O bonds with shorter bond length and larger Mulliken population make great contribution to hardness than Y-O bonds. Using quasi-harmonic Debye model considering the phonon effects, bulk modulus, heat capacity and thermal expansion coefficient of YVO{sub 4} are calculated within a range of 0-6 GPa and 0-1200 K. - Graphical Abstract: (a) Directional dependence of Young's modulus in zircon-type YVO{sub 4} and (b) projections of the directional dependent Young's modulus in different planes for zircon-type YVO{sub 4}. The units are in GPa. Highlights: Black-Right-Pointing-Pointer This paper systematically studied the physical properties of zircon-type YVO{sub 4} from first-principles calculations. Black-Right-Pointing-Pointer Zircon-type YVO{sub 4} is mechanically stable and it is ductile for B/G>1.75 and v>0.26. Black-Right-Pointing-Pointer Universal elastic anisotropy index A{sup U} for zircon-type YVO{sub 4} is 2.41, so YVO{sub 4} is anisotropic. Black-Right-Pointing-Pointer V-O bonds with shorter bond length and larger Mulliken population make greater contribution to the hardness of YVO{sub 4}.

  20. Physics Beyond the Standard Model from Molecular Hydrogen Spectroscopy

    NASA Astrophysics Data System (ADS)

    Ubachs, Wim; Salumbides, Edcel John; Bagdonaite, Julija

    2015-06-01

    The spectrum of molecular hydrogen can be measured in the laboratory to very high precision using advanced laser and molecular beam techniques, as well as frequency-comb based calibration [1,2]. The quantum level structure of this smallest neutral molecule can now be calculated to very high precision, based on a very accurate (10-15 precision) Born-Oppenheimer potential [3] and including subtle non-adiabatic, relativistic and quantum electrodynamic effects [4]. Comparison between theory and experiment yields a test of QED, and in fact of the Standard Model of Physics, since the weak, strong and gravitational forces have a negligible effect. Even fifth forces beyond the Standard Model can be searched for [5]. Astronomical observation of molecular hydrogen spectra, using the largest telescopes on Earth and in space, may reveal possible variations of fundamental constants on a cosmological time scale [6]. A study has been performed at a 'look-back' time of 12.5 billion years [7]. In addition the possible dependence of a fundamental constant on a gravitational field has been investigated from observation of molecular hydrogen in the photospheres of white dwarfs [8]. The latter involves a test of the Einsteins equivalence principle. [1] E.J. Salumbides et al., Phys. Rev. Lett. 107, 143005 (2011). [2] G. Dickenson et al., Phys. Rev. Lett. 110, 193601 (2013). [3] K. Pachucki, Phys. Rev. A82, 032509 (2010). [4] J. Komasa et al., J. Chem. Theory Comp. 7, 3105 (2011). [5] E.J. Salumbides et al., Phys. Rev. D87, 112008 (2013). [6] F. van Weerdenburg et al., Phys. Rev. Lett. 106, 180802 (2011). [7] J. Badonaite et al., Phys. Rev. Lett. 114, 071301 (2015). [8] J. Bagdonaite et al., Phys. Rev. Lett. 113, 123002 (2014).

  1. Speedminton: Using the Tactical Games Model in Secondary Physical Education

    ERIC Educational Resources Information Center

    Oh, Hyun-Ju; Bullard, Susan; Hovatter, Rhonda

    2011-01-01

    Teaching and learning of sport and sports-related games dominates the curriculum in most secondary physical education programs in America. For many secondary school students, playing games can be exciting and lead to a lifetime of participation in sport-related activities. Using the Tactical Games Model (TGM) (Mitchell et al., 2006) to teach the…

  2. Physical-scale models of engineered log jams in rivers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stream restoration and river engineering projects are employing engineered log jams increasingly for stabilization and in-stream improvements. To further advance the design of these structures and their morphodynamic effects on corridors, the basis for physical-scale models of rivers with engineere...

  3. Advanced Ground Systems Maintenance Physics Models for Diagnostics Project

    NASA Technical Reports Server (NTRS)

    Harp, Janicce Leshay

    2014-01-01

    The project will use high-fidelity physics models and simulations to simulate real-time operations of cryogenic and systems and calculate the status/health of the systems. The project enables the delivery of system health advisories to ground system operators. The capability will also be used to conduct planning and analysis of cryogenic system operations.

  4. Project Physics Text 5, Models of the Atom.

    ERIC Educational Resources Information Center

    Harvard Univ., Cambridge, MA. Harvard Project Physics.

    Basic atomic theories are presented in this fifth unit of the Project Physics text for use by senior high students. Chemical basis of atomic models in the early years of the 18th Century is discussed n connection with Dalton's theory, atomic properties, and periodic tables. The discovery of electrons is described by using cathode rays, Millikan's…

  5. Project Physics Tests 5, Models of the Atom.

    ERIC Educational Resources Information Center

    Harvard Univ., Cambridge, MA. Harvard Project Physics.

    Test items relating to Project Physics Unit 5 are presented in this booklet. Included are 70 multiple-choice and 23 problem-and-essay questions. Concepts of atomic model are examined on aspects of relativistic corrections, electron emission, photoelectric effects, Compton effect, quantum theories, electrolysis experiments, atomic number and mass,…

  6. Aspects of the Cognitive Model of Physics Problem Solving.

    ERIC Educational Resources Information Center

    Brekke, Stewart E.

    Various aspects of the cognitive model of physics problem solving are discussed in detail including relevant cues, encoding, memory, and input stimuli. The learning process involved in the recognition of familiar and non-familiar sensory stimuli is highlighted. Its four components include selection, acquisition, construction, and integration. The…

  7. Evaluation of an Interdisciplinary, Physically Active Lifestyle Course Model

    ERIC Educational Resources Information Center

    Fede, Marybeth H.

    2009-01-01

    The purpose of this study was to evaluate a fit for life program at a university and to use the findings from an extensive literature review, consultations with formative and summative committees, and data collection to develop an interdisciplinary, physically active lifestyle (IPAL) course model. To address the 5 research questions examined in…

  8. TOWARD EFFICIENT RIPARIAN RESTORATION: INTEGRATING ECONOMIC, PHYSICAL, AND BIOLOGICAL MODELS

    EPA Science Inventory

    This paper integrates economic, biological, and physical models to explore the efficient combination and spatial allocation of conservation efforts to protect water quality and increase salmonid populations in the Grande Ronde basin, Oregon. We focus on the effects of shade on wa...

  9. PHYSICAL AND NUMERICAL MODELING OF ASD EXHAUST DISPERSION AROUND HOUSES

    EPA Science Inventory

    The report discusses the use of a wind tunnel to physically model the dispersion of exhaust plumes from active soil depressurization (ASD) radon mitigation systems in houses. he testing studied the effects of exhaust location (grade level vs. above the eave), as house height, roo...

  10. The Role of Computer-Aided Modelling in Learning Physics.

    ERIC Educational Resources Information Center

    Niedderer, H.; And Others

    1991-01-01

    Described is how an iconic model building software can be used to help students gain a deeper qualitative conceptual understanding of physics concepts. The program, STELLA, links research about misconceptions and new teaching strategies with the use of modern information technology tools. (31 references) (KR)

  11. Linear Sigma Model Toolshed for D-brane Physics

    SciTech Connect

    Hellerman, Simeon

    2001-08-23

    Building on earlier work, we construct linear sigma models for strings on curved spaces in the presence of branes. Our models include an extremely general class of brane-worldvolume gauge field configurations. We explain in an accessible manner the mathematical ideas which suggest appropriate worldsheet interactions for generating a given open string background. This construction provides an explanation for the appearance of the derived category in D-brane physic complementary to that of recent work of Douglas.

  12. Plasma physics modeling and the Cray-2 multiprocessor

    SciTech Connect

    Killeen, J.

    1985-01-01

    The importance of computer modeling in the magnetic fusion energy research program is discussed. The need for the most advanced supercomputers is described. To meet the demand for more powerful scientific computers to solve larger and more complicated problems, the computer industry is developing multiprocessors. The role of the Cray-2 in plasma physics modeling is discussed with some examples. 28 refs., 2 figs., 1 tab.

  13. Two-fluid model for heavy electron physics

    NASA Astrophysics Data System (ADS)

    Yang, Yi-feng

    2016-07-01

    The two-fluid model is a phenomenological description of the gradual change of the itinerant and local characters of f-electrons with temperature and other tuning parameters and has been quite successful in explaining many unusual and puzzling experimental observations in heavy electron materials. We review some of these results and discuss possible implications of the two-fluid model in understanding the microscopic origin of heavy electron physics.

  14. Childhood physical abuse and midlife physical health: Testing a multi-pathway life course model

    PubMed Central

    Springer, K. W.

    2009-01-01

    Although prior research has established that childhood abuse adversely affects midlife physical health outcomes, it is unclear how abuse continues to harm health decades after the abuse has ended. In this project, I assess four life course pathways (behavioral, emotional, cognitive, and social relations) that plausibly link childhood physical abuse to three midlife physical health outcomes (bronchitis diagnosis, ulcer diagnosis, and general physical health). These three outcomes are etiologically distinct, leading to unique testable hypotheses. Multivariate models controlling for childhood background and early adversity were estimated using data from over 3,000 respondents in the Wisconsin Longitudinal Study, USA. The results indicate that midlife social relations and cognition do not function as pathways for any outcome. However, smoking is a crucial pathway connecting childhood abuse with bronchitis; mental health is important for ulcers; and BMI, smoking, and mental health are paramount for general physical health. These findings suggest that abuse survivors’ coping mechanisms can lead to an array of midlife health problems. Furthermore, the results validate the use of etiologically distinct outcomes for understanding plausible causal pathways when using cross-sectional data. PMID:19446943

  15. Childhood physical abuse and midlife physical health: testing a multi-pathway life course model.

    PubMed

    Springer, Kristen W

    2009-07-01

    Although prior research has established that childhood abuse adversely affects midlife physical health, it is unclear how abuse continues to harm health decades after the abuse has ended. In this project, I assess four life course pathways (health behaviors, cognition, mental health, and social relation) that plausibly link childhood physical abuse to three midlife physical health outcomes (bronchitis diagnosis, ulcer diagnosis, and general physical health). These three outcomes are etiologically distinct, leading to unique testable hypotheses. Multivariate models controlling for childhood background and early adversity were estimated using data from over 3000 respondents in the Wisconsin Longitudinal Study, USA. The results indicate that midlife social relations and cognition do not function as pathways for any outcome. However, smoking is a crucial pathway connecting childhood abuse with bronchitis; mental health is important for ulcers; and BMI, smoking, and mental health are paramount for general physical health. These findings suggest that abuse survivors' coping mechanisms can lead to an array of midlife health problems. Furthermore, the results validate the use of etiologically distinct outcomes for understanding plausible causal pathways when using cross-sectional data.

  16. Physical-Socio-Economic Modeling of Climate Change

    NASA Astrophysics Data System (ADS)

    Chamberlain, R. G.; Vatan, F.

    2008-12-01

    Because of the global nature of climate change, any assessment of the effects of plans, policies, and response to climate change demands a model that encompasses the entire Earth System, including socio- economic factors. Physics-based climate models of the factors that drive global temperatures, rainfall patterns, and sea level are necessary but not sufficient to guide decision making. Actions taken by farmers, industrialists, environmentalists, politicians, and other policy makers may result in large changes to economic factors, international relations, food production, disease vectors, and beyond. These consequences will not be felt uniformly around the globe or even across a given region. Policy models must comprehend all of these considerations. Combining physics-based models of the Earth's climate and biosphere with societal models of population dynamics, economics, and politics is a grand challenge with high stakes. We propose to leverage our recent advances in modeling and simulation of military stability and reconstruction operations to models that address all these areas of concern. Following over twenty years' experience of successful combat simulation, JPL has started developing Minerva, which will add demographic, economic, political, and media/information models to capabilities that already exist. With these new models, for which we have design concepts, it will be possible to address a very wide range of potential national and international problems that were previously inaccessible. Our climate change model builds on Minerva and expands the geographical horizon from playboxes containing regions and neighborhoods to the entire globe. This system consists of a collection of interacting simulation models that specialize in different aspects of the global situation. They will each contribute to and draw from a pool of shared data. The basic models are: the physical model; the demographic model; the political model; the economic model; and the media

  17. Evaluating performances of simplified physically based models for landslide susceptibility

    NASA Astrophysics Data System (ADS)

    Formetta, G.; Capparelli, G.; Versace, P.

    2015-12-01

    Rainfall induced shallow landslides cause loss of life and significant damages involving private and public properties, transportation system, etc. Prediction of shallow landslides susceptible locations is a complex task that involves many disciplines: hydrology, geotechnical science, geomorphology, and statistics. Usually to accomplish this task two main approaches are used: statistical or physically based model. Reliable models' applications involve: automatic parameters calibration, objective quantification of the quality of susceptibility maps, model sensitivity analysis. This paper presents a methodology to systemically and objectively calibrate, verify and compare different models and different models performances indicators in order to individuate and eventually select the models whose behaviors are more reliable for a certain case study. The procedure was implemented in package of models for landslide susceptibility analysis and integrated in the NewAge-JGrass hydrological model. The package includes three simplified physically based models for landslides susceptibility analysis (M1, M2, and M3) and a component for models verifications. It computes eight goodness of fit indices by comparing pixel-by-pixel model results and measurements data. Moreover, the package integration in NewAge-JGrass allows the use of other components such as geographic information system tools to manage inputs-output processes, and automatic calibration algorithms to estimate model parameters. The system was applied for a case study in Calabria (Italy) along the Salerno-Reggio Calabria highway, between Cosenza and Altilia municipality. The analysis provided that among all the optimized indices and all the three models, the optimization of the index distance to perfect classification in the receiver operating characteristic plane (D2PC) coupled with model M3 is the best modeling solution for our test case.

  18. Pre-Service Physics Teachers' Knowledge of Models and Perceptions of Modelling

    ERIC Educational Resources Information Center

    Ogan-Bekiroglu, Feral

    2006-01-01

    One of the purposes of this study was to examine the differences between knowledge of pre-service physics teachers who experienced model-based teaching in pre-service education and those who did not. Moreover, it was aimed to determine pre-service physics teachers' perceptions of modelling. Posttest-only control group experimental design was used…

  19. Rock Physics Models of Biofilm Growth in Porous Media

    NASA Astrophysics Data System (ADS)

    Jaiswal, P.; alhadhrami, F. M.; Atekwana, E. A.

    2013-12-01

    Recent studies suggest the potential to use acoustic techniques to image biofilm growth in porous media. Nonetheless the interpretation of the seismic response to biofilm growth and development remains speculative because of the lack of quantitative petrophysical models that can relate changes in biofilm saturation to changes in seismic attributes. Here, we report our efforts in developing quantitative rock physics models to biofilm saturation with increasing and decreasing P-wave velocity (VP) and amplitudes recorded in the Davis et al. [2010] physical scale experiment. We adapted rock physics models developed for modeling gas hydrates in unconsolidated sediments. Two distinct growth models, which appear to be a function of pore throat size, are needed to explain the experimental data. First, introduction of biofilm as an additional mineral grain in the sediment matrix (load-bearing mode) is needed to explain the increasing time-lapse VP. Second, introduction of biofilm as part of the pore fluid (pore-filling mode) is required to explain the decreasing time-lapse VP. To explain the time-lapse VP, up to 15% of the pore volume was required to be saturated with biofilm. The recorded seismic amplitudes, which can be expressed as a function of porosity, permeability and grain size, showed a monotonic time-lapse decay except on Day 3 at a few selected locations, where it increased. Since porosity changes are constrained by VP, amplitude increase could be modeled by increasing hydraulic conductivity. Time lapse VP at locations with increasing amplitudes suggest that these locations have a load-bearing growth style. We conclude that permeability can increase by up to 10% at low (~2%) biofilm saturation in load-bearing growth style due to the development of channels within the biofilm structure. Developing a rock physics model for the biofilm growth in general may help create a field guide for interpreting porosity and permeability changes in bioremediation, MEOR and

  20. Barriers to transport induced by periodic oscillations in a physical model of the human vitreous chamber

    NASA Astrophysics Data System (ADS)

    Oliveri, Alberto; Stocchino, Alessandro; Storace, Marco

    2011-03-01

    Understanding mixing processes that occur in the human vitreous chamber is of fundamental importance due to the relevant clinical implications in drug delivery treatments of several eye conditions. In this article we rely on experimental observations (which demonstrated that dispersion coefficients largely dominate diffusive coefficients) on a physical model of the human eye to perform an analysis based on Lagrangian trajectories. In particular, we study barriers to transport in a particularly significant two-dimensional section of the eye model by using nonlinear dynamical systems theoretical and numerical tools. Bifurcations in the system dynamics are investigated by varying the main physical parameters of the problem.

  1. Barriers to transport induced by periodic oscillations in a physical model of the human vitreous chamber.

    PubMed

    Oliveri, Alberto; Stocchino, Alessandro; Storace, Marco

    2011-03-01

    Understanding mixing processes that occur in the human vitreous chamber is of fundamental importance due to the relevant clinical implications in drug delivery treatments of several eye conditions. In this article we rely on experimental observations (which demonstrated that dispersion coefficients largely dominate diffusive coefficients) on a physical model of the human eye to perform an analysis based on Lagrangian trajectories. In particular, we study barriers to transport in a particularly significant two-dimensional section of the eye model by using nonlinear dynamical systems theoretical and numerical tools. Bifurcations in the system dynamics are investigated by varying the main physical parameters of the problem.

  2. The ESA Meteoroid Model 2010: Enhanced Physical Model

    NASA Astrophysics Data System (ADS)

    Dikarev, Valeri; Mints, Alexey; Drolshagen, Gerhard

    The orbital distributions of meteoroids in interplanetary space are revised in the ESA meteoroid model. In the present update, the chemical composition of the meteoroids is simulated in more detail than in the previous meteoroid models. Silicate and carbonaceous fractions are introduced for all meteoroid populations, and in addition to asteroids and Jupiter-crossing comets, comet 2P/Encke is added as a source. The orbital evolution under planetary gravity, Poynting-Robertson effect and mutual collisions is simulated using analytical approximations. Infrared observations of the zodiacal cloud by the COBE DIRBE instrument, in situ flux measurements by the dust detectors on board Galileo, Ulysses, Pioneer 11 and Helios-1 spacecraft, and the crater size distributions on lunar rock samples retrieved by the Apollo missions are incorporated in the model.

  3. Application of physical parameter identification to finite-element models

    NASA Technical Reports Server (NTRS)

    Bronowicki, Allen J.; Lukich, Michael S.; Kuritz, Steven P.

    1987-01-01

    The time domain parameter identification method described previously is applied to TRW's Large Space Structure Truss Experiment. Only control sensors and actuators are employed in the test procedure. The fit of the linear structural model to the test data is improved by more than an order of magnitude using a physically reasonable parameter set. The electro-magnetic control actuators are found to contribute significant damping due to a combination of eddy current and back electro-motive force (EMF) effects. Uncertainties in both estimated physical parameters and modal behavior variables are given.

  4. Model Independent Search For New Physics At The Tevatron

    SciTech Connect

    Choudalakis, Georgios

    2008-04-01

    The Standard Model of elementary particles can not be the final theory. There are theoretical reasons to expect the appearance of new physics, possibly at the energy scale of few TeV. Several possible theories of new physics have been proposed, each with unknown probability to be confirmed. Instead of arbitrarily choosing to examine one of those theories, this thesis is about searching for any sign of new physics in a model-independent way. This search is performed at the Collider Detector at Fermilab (CDF). The Standard Model prediction is implemented in all final states simultaneously, and an array of statistical probes is employed to search for significant discrepancies between data and prediction. The probes are sensitive to overall population discrepancies, shape disagreements in distributions of kinematic quantities of final particles, excesses of events of large total transverse momentum, and local excesses of data expected from resonances due to new massive particles. The result of this search, first in 1 fb-1 and then in 2 fb-1, is null, namely no considerable evidence of new physics was found.

  5. Crossing borders between social and physical sciences in post-event investigations

    NASA Astrophysics Data System (ADS)

    Ruin, I.; Gruntfest, E.; Lutoff, C.; Anquetin, S.; Scolobig, A.; Creutin, J.-D.; Borga, M.

    2009-04-01

    In natural hazard research social and physical scientists tend to approach post-event investigations within their narrow disciplinary lenses. Efforts that are called trans-disciplinary often add social science but do not integrate it effectively. For example, an economist might be brought in to address a question of "value" without any understanding or interest in the context in which the value will be applied (e.g., Merrell et al. 2002, Simmons and Sutter 2005). At the same time, social scientists would benefit from some knowledge of geology, meteorology, hydrology, forecasting operations, and hazard detection systems in order, for instance, to understand the nature and types of uncertainty in the physical systems. Proactive partnership between social and physical scientists in post-event investigations needs a background knowledge and a preparation about several issues from both sides. Moreover neither physical nor social scientists necessarily understand and appreciate the contributions that they can reciprocally bring to their works. Post-event collaborations between social and physical science are rare. The few examples of multi-disciplinary work, when examined closely, are not integrated collaborative projects but patchwork quilts of a variety of specialists taking separate aspects of an issue. There are examples where social scientists and engineers are engaged in one project, but the efforts tend to include social scientists as an "add on" to an existing physical science investigation. In this way, true integration of information, data and knowledge from different fields is lacking and the result is that neither the physical nor the social science perspectives gain a comprehensive picture of the issue under scrutiny. Looking at the flash flood problem, the atmospheric and hydrological generating mechanisms of the phenomenon are poorly understood, leading to highly uncertain forecasts of and warnings for these events. On the other hand warning and crisis

  6. Precision Higgs Boson Physics and Implications for Beyond the Standard Model Physics Theories

    SciTech Connect

    Wells, James

    2015-06-10

    The discovery of the Higgs boson is one of science's most impressive recent achievements. We have taken a leap forward in understanding what is at the heart of elementary particle mass generation. We now have a significant opportunity to develop even deeper understanding of how the fundamental laws of nature are constructed. As such, we need intense focus from the scientific community to put this discovery in its proper context, to realign and narrow our understanding of viable theory based on this positive discovery, and to detail the implications the discovery has for theories that attempt to answer questions beyond what the Standard Model can explain. This project's first main object is to develop a state-of-the-art analysis of precision Higgs boson physics. This is to be done in the tradition of the electroweak precision measurements of the LEP/SLC era. Indeed, the electroweak precision studies of the past are necessary inputs to the full precision Higgs program. Calculations will be presented to the community of Higgs boson observables that detail just how well various couplings of the Higgs boson can be measured, and more. These will be carried out using state-of-the-art theory computations coupled with the new experimental results coming in from the LHC. The project's second main objective is to utilize the results obtained from LHC Higgs boson experiments and the precision analysis, along with the direct search studies at LHC, and discern viable theories of physics beyond the Standard Model that unify physics to a deeper level. Studies will be performed on supersymmetric theories, theories of extra spatial dimensions (and related theories, such as compositeness), and theories that contain hidden sector states uniquely accessible to the Higgs boson. In addition, if data becomes incompatible with the Standard Model's low-energy effective lagrangian, new physics theories will be developed that explain the anomaly and put it into a more unified framework beyond

  7. Physical and numerical investigation of cavitating flows around a pitching hydrofoil

    NASA Astrophysics Data System (ADS)

    Huang, Biao; Ducoin, Antoine; Young, Yin Lu

    2013-10-01

    The objective of this paper is to investigate cavitating flows around a pitching hydrofoil via combined physical and numerical studies. The aims are to (1) improve the understanding of the interplay between unsteady cavitating flow, hydrofoil motion, and hydrodynamic performance, (2) quantify the influence of pitching rate on subcavitating and cavitating responses, and (3) quantify the influence of cavitation on the hydrodynamic load coefficients and surrounding flow structures. Results are presented for a NACA66 hydrofoil undergoing controlled, slow (dot α = 6^circ /s) and fast (dot α = 63^circ /s) pitching motions from α = 0° to α = 15° and back to α = 0° for both subcavitating and cavitating conditions at a moderate Reynolds number of Re = 750 000. The experimental studies were conducted in a cavitation tunnel at the French Naval Academy, France. The numerical simulations are performed by solving the incompressible, multiphase Unsteady Reynolds-Averaged Navier-Stokes Equations via the commercial code CFX using a transport equation-based cavitation model; a modified k-ω SST turbulence model is used to account for the effect of local compressibility on the turbulent eddy viscosity. The results showed that increases in the pitching rate suppressed laminar to turbulent transition, delayed stall, and significantly modified post-stall behavior. Cavitation inception at the leading edge modified the pressure distribution, which in turn significantly changed the interaction between leading edge and trailing edge vortices, and hence the magnitude as well as the frequency of the load fluctuations. For a fixed cavitation number, increases in pitching rate lead to increase in cavitation volume, which in turn changed the cavity shedding frequencies and significantly modified the hydrodynamic loads. Inversely, the leading edge cavitation observed for the low pitching velocity case tends to stabilize the stall because of the decrease of the pressure gradient due to the

  8. Comparing Self-Reported Versus Objectively Measured Physical Activity Behavior: A Preliminary Investigation of Older Filipino American Women

    ERIC Educational Resources Information Center

    Atienza, Audie A.; King, Abby C.

    2005-01-01

    The importance of examining health behaviors, such as physical activity, among Filipino Americans is highlighted by their higher rates of chronic disease. As physical inactivity has been linked to chronic diseases (U.S. Department of Health and Human Services, 1996), this study investigated the physical activity levels of older Filipinas. This…

  9. Unifying wildfire models from ecology and statistical physics.

    PubMed

    Zinck, Richard D; Grimm, Volker

    2009-11-01

    Understanding the dynamics of wildfire regimes is crucial for both regional forest management and predicting global interactions between fire regimes and climate. Accordingly, spatially explicit modeling of forest fire ecosystems is a very active field of research, including both generic and highly specific models. There is, however, a second field in which wildfire has served as a metaphor for more than 20 years: statistical physics. So far, there has been only limited interaction between these two fields of wildfire modeling. Here we show that two typical generic wildfire models from ecology are structurally equivalent to the most commonly used model from statistical physics. All three models can be unified to a single model in which they appear as special cases of regrowth-dependent flammability. This local "ecological memory" of former fire events is key to self-organization in wildfire ecosystems. The unified model is able to reproduce three different patterns observed in real boreal forests: fire size distributions, fire shapes, and a hump-shaped relationship between disturbance intensity (average annual area burned) and diversity of succession stages. The unification enables us to bring together insights from both disciplines in a novel way and to identify limitations that provide starting points for further research.

  10. Unifying wildfire models from ecology and statistical physics.

    PubMed

    Zinck, Richard D; Grimm, Volker

    2009-11-01

    Understanding the dynamics of wildfire regimes is crucial for both regional forest management and predicting global interactions between fire regimes and climate. Accordingly, spatially explicit modeling of forest fire ecosystems is a very active field of research, including both generic and highly specific models. There is, however, a second field in which wildfire has served as a metaphor for more than 20 years: statistical physics. So far, there has been only limited interaction between these two fields of wildfire modeling. Here we show that two typical generic wildfire models from ecology are structurally equivalent to the most commonly used model from statistical physics. All three models can be unified to a single model in which they appear as special cases of regrowth-dependent flammability. This local "ecological memory" of former fire events is key to self-organization in wildfire ecosystems. The unified model is able to reproduce three different patterns observed in real boreal forests: fire size distributions, fire shapes, and a hump-shaped relationship between disturbance intensity (average annual area burned) and diversity of succession stages. The unification enables us to bring together insights from both disciplines in a novel way and to identify limitations that provide starting points for further research. PMID:19799499

  11. Physically-based modeling and simulation of extraocular muscles.

    PubMed

    Wei, Qi; Sueda, Shinjiro; Pai, Dinesh K

    2010-12-01

    Dynamic simulation of human eye movements, with realistic physical models of extraocular muscles (EOMs), may greatly advance our understanding of the complexities of the oculomotor system and aid in treatment of visuomotor disorders. In this paper we describe the first three dimensional (3D) biomechanical model which can simulate the dynamics of ocular motility at interactive rates. We represent EOMs using "strands", which are physical primitives that can model an EOM's complex nonlinear anatomical and physiological properties. Contact between the EOMs, the globe, and orbital structures can be explicitly modeled. Several studies were performed to assess the validity and utility of the model. EOM deformation during smooth pursuit was simulated and compared with published experimental data; the model reproduces qualitative features of the observed nonuniformity. The model is able to reproduce realistic saccadic trajectories when the lateral rectus muscle was driven by published measurements of abducens neuron discharge. Finally, acute superior oblique palsy, a pathological condition, was simulated to further evaluate the system behavior; the predicted deviation patterns agree qualitatively with experimental observations. This example also demonstrates potential clinical applications of such a model. PMID:20868704

  12. Evaluating plume dispersion models: Expanding the practice to include the model physics

    SciTech Connect

    Weil, J.C.

    1994-12-31

    Plume dispersion models are used in a variety of air-quality applications including the determination of source emission limits, new source sites, etc. The cost of pollution control and siting has generated much interest in model evaluation and accuracy. Two questions are of primary concern: (1) How well does a model predict the high ground-level concentrations (GLCs) that are necessary in assessing compliance with air-quality regulations? This prompts an operational performance evaluation; (2) Is the model based on sound physical principles and does it give good predictions for the {open_quotes}right{close_quotes} reasons? This prompts a model physics evaluation. Although air-quality managers are interested primarily in operational performance, model physics should be an equally important issue. The purpose in establishing good physics is to build confidence in model predictions beyond the limited experimental range, i.e., for new source applications.

  13. Microphysics in Multi-scale Modeling System with Unified Physics

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo

    2012-01-01

    Recently, a multi-scale modeling system with unified physics was developed at NASA Goddard. It consists of (1) a cloud-resolving model (Goddard Cumulus Ensemble model, GCE model), (2) a regional scale model (a NASA unified weather research and forecast, WRF), (3) a coupled CRM and global model (Goddard Multi-scale Modeling Framework, MMF), and (4) a land modeling system. The same microphysical processes, long and short wave radiative transfer and land processes and the explicit cloud-radiation, and cloud-land surface interactive processes are applied in this multi-scale modeling system. This modeling system has been coupled with a multi-satellite simulator to use NASA high-resolution satellite data to identify the strengths and weaknesses of cloud and precipitation processes simulated by the model. In this talk, a review of developments and applications of the multi-scale modeling system will be presented. In particular, the microphysics development and its performance for the multi-scale modeling system will be presented.

  14. Use of Chemical and Physical Characteristics To Investigate Trends in Biochar Feedstocks

    PubMed Central

    Mukome, Fungai N. D.; Zhang, Xiaoming; Silva, Lucas C. R.; Six, Johan; Parikh, Sanjai J.

    2014-01-01

    Studies have shown that pyrolysis method and temperature are the key factors influencing biochar chemical and physical properties; however, information on the nature of biochar feedstocks is more accessible to consumers, making feedstock a better measure for selecting biochars. This study characterizes physical and chemical properties of commercially available biochars and investigates trends in biochar properties related to feedstock material to develop guidelines for biochar use. Twelve biochars were analyzed for physical and chemical properties. Compiled data from this study and from the literature (n = 85) were used to investigate trends in biochar characteristics related to feedstock. Analysis of compiled data reveals that despite clear differences in biochar properties from feedstocks of algae, grass, manure, nutshells, pomace, and wood (hard- and softwoods), characteristic generalizations can be made. Feedstock was a better predictor of biochar ash content and C/N ratio, but surface area was also temperature dependent for wood-derived biochar. Significant differences in ash content (grass and manure > wood) and C/N ratio (softwoods > grass and manure) enabled the first presentation of guidelines for biochar use based on feedstock material. PMID:23343098

  15. Physical security and vulnerability modeling for infrasturcture facilities.

    SciTech Connect

    Nozick, Linda Karen; Jones, Dean A.; Davis, Chad Edward; Turnquist, Mark Alan

    2006-07-01

    A model of malicious intrusions in infrastructure facilities is developed, using a network representation of the system structure together with Markov models of intruder progress and strategy. This structure provides an explicit mechanism to estimate the probability of successful breaches of physical security, and to evaluate potential improvements. Simulation is used to analyze varying levels of imperfect information on the part of the intruders in planning their attacks. An example of an intruder attempting to place an explosive device on an airplane at an airport gate illustrates the structure and potential application of the model.

  16. Channel and physical models of the Jovian subnebula

    NASA Technical Reports Server (NTRS)

    Lewis, J. S.

    1982-01-01

    A semiempirical physical model of the Jovian subnebula was developed by analogy with the primitive solar nebula itself. The chemical aspects of this model are developed according to the principles developed in the study of the thermochemistry and gas kinetic behavior of the solar nebula, but with important modifications to take into account the higher pressures and densities in the Jovian subnebula. The bulk compositions and densities of the inner satellites of Jupiter are calculated. It is proposed that Europa differs from Io chiefly in that in has suffered a less severe thermal history. The general features of this model are applicable with minor modification to the systems of Saturn and Uranus.

  17. Physics-Based Reactive Burn Model: Grain Size Effects

    NASA Astrophysics Data System (ADS)

    Lu, X.; Hamate, Y.; Horie, Y.

    2007-12-01

    We have been developing a physics-based reactive burn (PBRB) model, which was formulated based on the concept of a statistical hot spot cell. In the model, essential thermomechanics and physiochemical features are explicitly modeled. In this paper, we have extended the statistical hot spot model to explicitly describe the ignition and growth of hot spots. In particular, grain size effects are explicitly delineated through introduction of grain size-dependent, thickness of the hot-region, energy deposition criterion, and specific surface area. Besides the linear relationships between the run distance to detonation and the critical diameter with respect to the reciprocal specific surface area of heterogeneous explosives (HE), which is based on the original model and discussed in a parallel paper of this meeting, parametric studies have shown that the extended PBRB model can predict a non-monotonic variation of shock sensitivity with grain size, as observed by Moulard et al.

  18. An integrated physical and biological model for anaerobic lagoons.

    PubMed

    Wu, Binxin; Chen, Zhenbin

    2011-04-01

    A computational fluid dynamics (CFD) model that integrates physical and biological processes for anaerobic lagoons is presented. In the model development, turbulence is represented using a transition k-ω model, heat conduction and solar radiation are included in the thermal model, biological oxygen demand (BOD) reduction is characterized by first-order kinetics, and methane yield rate is expressed as a linear function of temperature. A test of the model applicability is conducted in a covered lagoon digester operated under tropical climate conditions. The commercial CFD software, ANSYS-Fluent, is employed to solve the integrated model. The simulation procedures include solving fluid flow and heat transfer, predicting local resident time based on the converged flow fields, and calculating the BOD reduction and methane production. The simulated results show that monthly methane production varies insignificantly, but the time to achieve a 99% BOD reduction in January is much longer than that in July.

  19. A Framework for Understanding Physics Students' Computational Modeling Practices

    NASA Astrophysics Data System (ADS)

    Lunk, Brandon Robert

    With the growing push to include computational modeling in the physics classroom, we are faced with the need to better understand students' computational modeling practices. While existing research on programming comprehension explores how novices and experts generate programming algorithms, little of this discusses how domain content knowledge, and physics knowledge in particular, can influence students' programming practices. In an effort to better understand this issue, I have developed a framework for modeling these practices based on a resource stance towards student knowledge. A resource framework models knowledge as the activation of vast networks of elements called "resources." Much like neurons in the brain, resources that become active can trigger cascading events of activation throughout the broader network. This model emphasizes the connectivity between knowledge elements and provides a description of students' knowledge base. Together with resources resources, the concepts of "epistemic games" and "frames" provide a means for addressing the interaction between content knowledge and practices. Although this framework has generally been limited to describing conceptual and mathematical understanding, it also provides a means for addressing students' programming practices. In this dissertation, I will demonstrate this facet of a resource framework as well as fill in an important missing piece: a set of epistemic games that can describe students' computational modeling strategies. The development of this theoretical framework emerged from the analysis of video data of students generating computational models during the laboratory component of a Matter & Interactions: Modern Mechanics course. Student participants across two semesters were recorded as they worked in groups to fix pre-written computational models that were initially missing key lines of code. Analysis of this video data showed that the students' programming practices were highly influenced by

  20. Influence of a health-related physical fitness model on students' physical activity, perceived competence, and enjoyment.

    PubMed

    Fu, You; Gao, Zan; Hannon, James; Shultz, Barry; Newton, Maria; Sibthorp, Jim

    2013-12-01

    This study was designed to explore the effects of a health-related physical fitness physical education model on students' physical activity, perceived competence, and enjoyment. 61 students (25 boys, 36 girls; M age = 12.6 yr., SD = 0.6) were assigned to two groups (health-related physical fitness physical education group, and traditional physical education group), and participated in one 50-min. weekly basketball class for 6 wk. Students' in-class physical activity was assessed using NL-1000 pedometers. The physical subscale of the Perceived Competence Scale for Children was employed to assess perceived competence, and children's enjoyment was measured using the Sport Enjoyment Scale. The findings suggest that students in the intervention group increased their perceived competence, enjoyment, and physical activity over a 6-wk. intervention, while the comparison group simply increased physical activity over time. Children in the intervention group had significantly greater enjoyment.

  1. Open-Ended Laboratory Investigations in a High School Physics Course: The Difficulties and Rewards of Implementing Inquiry-Based Learning in a Physics Lab

    ERIC Educational Resources Information Center

    Szott, Aaron

    2014-01-01

    Traditional physics labs at the high school level are often closed-ended. The outcomes are known in advance and students replicate procedures recommended by the teacher. Over the years, I have come to appreciate the great opportunities created by allowing students investigative freedom in physics laboratories. I have realized that a laboratory…

  2. A Goddard Multi-Scale Modeling System with Unified Physics

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo

    2010-01-01

    A multi-scale modeling system with unified physics has been developed at NASA Goddard Space Flight Center (GSFC). The system consists of an MMF, the coupled NASA Goddard finite-volume GCM (fvGCM) and Goddard Cumulus Ensemble model (GCE, a CRM); the state-of-the-art Weather Research and Forecasting model (WRF) and the stand alone GCE. These models can share the same microphysical schemes, radiation (including explicitly calculated cloud optical properties), and surface models that have been developed, improved and tested for different environments. In this talk, I will present: (1) A brief review on GCE model and its applications on the impact of the aerosol on deep precipitation processes, (2) The Goddard MMF and the major difference between two existing MMFs (CSU MMF and Goddard MMF), and preliminary results (the comparison with traditional GCMs), and (3) A discussion on the Goddard WRF version (its developments and applications). We are also performing the inline tracer calculation to comprehend the physical processes (i.e., boundary layer and each quadrant in the boundary layer) related to the development and structure of hurricanes and mesoscale convective systems. In addition, high - resolution (spatial. 2km, and temporal, I minute) visualization showing the model results will be presented.

  3. Earthquake research: Premonitory models and the physics of crustal distortion

    NASA Technical Reports Server (NTRS)

    Whitcomb, J. H.

    1981-01-01

    Seismic, gravity, and electrical resistivity data, believed to be most relevent to development of earthquake premonitory models of the crust, are presented. Magnetotellurics (MT) are discussed. Radon investigations are reviewed.

  4. A physically based model of global freshwater surface temperature

    NASA Astrophysics Data System (ADS)

    Beek, Ludovicus P. H.; Eikelboom, Tessa; Vliet, Michelle T. H.; Bierkens, Marc F. P.

    2012-09-01

    Temperature determines a range of physical properties of water and exerts a strong control on surface water biogeochemistry. Thus, in freshwater ecosystems the thermal regime directly affects the geographical distribution of aquatic species through their growth and metabolism and indirectly through their tolerance to parasites and diseases. Models used to predict surface water temperature range between physically based deterministic models and statistical approaches. Here we present the initial results of a physically based deterministic model of global freshwater surface temperature. The model adds a surface water energy balance to river discharge modeled by the global hydrological model PCR-GLOBWB. In addition to advection of energy from direct precipitation, runoff, and lateral exchange along the drainage network, energy is exchanged between the water body and the atmosphere by shortwave and longwave radiation and sensible and latent heat fluxes. Also included are ice formation and its effect on heat storage and river hydraulics. We use the coupled surface water and energy balance model to simulate global freshwater surface temperature at daily time steps with a spatial resolution of 0.5° on a regular grid for the period 1976-2000. We opt to parameterize the model with globally available data and apply it without calibration in order to preserve its physical basis with the outlook of evaluating the effects of atmospheric warming on freshwater surface temperature. We validate our simulation results with daily temperature data from rivers and lakes (U.S. Geological Survey (USGS), limited to the USA) and compare mean monthly temperatures with those recorded in the Global Environment Monitoring System (GEMS) data set. Results show that the model is able to capture the mean monthly surface temperature for the majority of the GEMS stations, while the interannual variability as derived from the USGS and NOAA data was captured reasonably well. Results are poorest for

  5. A robotic model to investigate human motor control.

    PubMed

    Lenzi, Tommaso; Vitiello, Nicola; McIntyre, Joseph; Roccella, Stefano; Carrozza, Maria Chiara

    2011-07-01

    The role of the mechanical properties of the neuromuscular system in motor control has been investigated for a long time in both human and animal subjects, mainly through the application of mechanical perturbations to the limb during natural movements and the observation of its corrective responses. These methods have provided a wealth of insight into how the central nervous system controls the limb. They suffer, however, from the fact that it is almost impossible to separate the active and passive components of the measured arm stiffness and that the measurement may themselves alter the stiffness characteristic of the arm. As a complement to these analyses, the implementation of a given neuroscientific hypothesis on a real mechanical system could overcome these measurement artifact and provide a tool that is, under full control of the experimenter, able to replicate the relevant functional features of the human arm. In this article, we introduce the NEURARM platform, a robotic arm intended to test hypotheses on the human motor control system. As such, NEURARM satisfies two key requirements. First, its kinematic parameters and inertia are similar to that of the human arm. Second, NEURARM mimics the main physical features of the human actuation system, specifically, the use of tendons to transfer force, the presence of antagonistic muscle pairs, the passive elasticity of muscles in the absence of any neural feedback and the non-linear elastic behaviour. This article presents the design and characterization of the NEURARM actuation system. The resulting mechanical behaviour, which has been tested in joint and Cartesian space under static and dynamic conditions, proves that the NEURARM platform can be exploited as a robotic model of the human arm, and could thus represent a powerful tool for neuroscience investigations.

  6. Dynamic inverse models in human-cyber-physical systems

    NASA Astrophysics Data System (ADS)

    Robinson, Ryan M.; Scobee, Dexter R. R.; Burden, Samuel A.; Sastry, S. Shankar

    2016-05-01

    Human interaction with the physical world is increasingly mediated by automation. This interaction is characterized by dynamic coupling between robotic (i.e. cyber) and neuromechanical (i.e. human) decision-making agents. Guaranteeing performance of such human-cyber-physical systems will require predictive mathematical models of this dynamic coupling. Toward this end, we propose a rapprochement between robotics and neuromechanics premised on the existence of internal forward and inverse models in the human agent. We hypothesize that, in tele-robotic applications of interest, a human operator learns to invert automation dynamics, directly translating from desired task to required control input. By formulating the model inversion problem in the context of a tracking task for a nonlinear control system in control-a_ne form, we derive criteria for exponential tracking and show that the resulting dynamic inverse model generally renders a portion of the physical system state (i.e., the internal dynamics) unobservable from the human operator's perspective. Under stability conditions, we show that the human can achieve exponential tracking without formulating an estimate of the system's state so long as they possess an accurate model of the system's dynamics. These theoretical results are illustrated using a planar quadrotor example. We then demonstrate that the automation can intervene to improve performance of the tracking task by solving an optimal control problem. Performance is guaranteed to improve under the assumption that the human learns and inverts the dynamic model of the altered system. We conclude with a discussion of practical limitations that may hinder exact dynamic model inversion.

  7. Experimental Investigation and Modeling of Copper Smelting Slags

    NASA Astrophysics Data System (ADS)

    Starodub, Konstantin; Kuminova, Yaroslava; Dinsdale, Alan; Cheverikin, Vladimir; Filichkina, Vera; Saynazarov, Abdukahhar; Khvan, Alexandra; Kondratiev, Alex

    2016-07-01

    Effective extraction of copper from sulfide ores requires careful operation of a copper smelter, which in turn depends very much on chemistry of the feed and resulted slag and matte. For example, chemical composition of copper smelting slags has to be in a certain range to ensure that their properties are within specific limits. Disobeying these rules may lead to complications in smelting operation, poor quality of the copper products, and premature shutdown of the copper smelter. In the present paper the microstructure and phase composition of slags from the Almalyk copper flash smelter were investigated experimentally and then modeled thermodynamically to evaluate potential ways of improvement and optimization of the copper smelting process and its products. The slag samples were taken at different stages of the copper smelting process: on slag tapping, after slag transportation to a deposition site, and at the site. Experimental investigation included the XRD, XRF, and SEM techniques, which were also confirmed by the traditional wet chemistry analysis. Thermodynamic modeling was carried out using thermochemical software package MTDATA, which enables thermodynamic and physical properties of the matte, slag, and gas phases to be calculated in a wide range of temperatures, pressures, and chemical compositions. In addition, slag viscosities and corresponding matte settling rates were estimated using the modified Urbain and Utigard-Warczok models, and the Hadamard-Rybczynski equation, respectively. It was found that the copper content in the slags may vary significantly depending on the location of slag sampling. Cu was found to be present as sulfide particles, almost no Cu was found to be dissolved in the slag. Analysis of microstructure and phase composition showed that major phase found in the samples is fayalite, while other phases are complex spinels (based on magnetite), different sulfides, and a glass-like phase. Thermodynamic calculations demonstrated the

  8. Experimental Investigation and Modeling of Copper Smelting Slags

    NASA Astrophysics Data System (ADS)

    Starodub, Konstantin; Kuminova, Yaroslava; Dinsdale, Alan; Cheverikin, Vladimir; Filichkina, Vera; Saynazarov, Abdukahhar; Khvan, Alexandra; Kondratiev, Alex

    2016-10-01

    Effective extraction of copper from sulfide ores requires careful operation of a copper smelter, which in turn depends very much on chemistry of the feed and resulted slag and matte. For example, chemical composition of copper smelting slags has to be in a certain range to ensure that their properties are within specific limits. Disobeying these rules may lead to complications in smelting operation, poor quality of the copper products, and premature shutdown of the copper smelter. In the present paper the microstructure and phase composition of slags from the Almalyk copper flash smelter were investigated experimentally and then modeled thermodynamically to evaluate potential ways of improvement and optimization of the copper smelting process and its products. The slag samples were taken at different stages of the copper smelting process: on slag tapping, after slag transportation to a deposition site, and at the site. Experimental investigation included the XRD, XRF, and SEM techniques, which were also confirmed by the traditional wet chemistry analysis. Thermodynamic modeling was carried out using thermochemical software package MTDATA, which enables thermodynamic and physical properties of the matte, slag, and gas phases to be calculated in a wide range of temperatures, pressures, and chemical compositions. In addition, slag viscosities and corresponding matte settling rates were estimated using the modified Urbain and Utigard-Warczok models, and the Hadamard-Rybczynski equation, respectively. It was found that the copper content in the slags may vary significantly depending on the location of slag sampling. Cu was found to be present as sulfide particles, almost no Cu was found to be dissolved in the slag. Analysis of microstructure and phase composition showed that major phase found in the samples is fayalite, while other phases are complex spinels (based on magnetite), different sulfides, and a glass-like phase. Thermodynamic calculations demonstrated the

  9. An experimental investigation of the flow physics of high-lift systems

    NASA Technical Reports Server (NTRS)

    Thomas, Flint O.; Nelson, R. C.

    1995-01-01

    This progress report, a series of viewgraphs, outlines experiments on the flow physics of confluent boundary layers for high lift systems. The design objective is to design high lift systems with improved C(sub Lmax) for landing approach and improved take-off L/D and simultaneously reduce acquisition and maintenance costs. In effect, achieve improved performance with simpler designs. The research objectives include: establish the role of confluent boundary layer flow physics in high-lift production; contrast confluent boundary layer structure for optimum and non-optimum C(sub L) cases; formation of a high quality, detailed archival data base for CFD/modeling; and examination of the role of relaminarization and streamline curvature.

  10. A minimal physical model captures the shapes of crawling cells

    NASA Astrophysics Data System (ADS)

    Tjhung, E.; Tiribocchi, A.; Marenduzzo, D.; Cates, M. E.

    2015-01-01

    Cell motility in higher organisms (eukaryotes) is crucial to biological functions ranging from wound healing to immune response, and also implicated in diseases such as cancer. For cells crawling on hard surfaces, significant insights into motility have been gained from experiments replicating such motion in vitro. Such experiments show that crawling uses a combination of actin treadmilling (polymerization), which pushes the front of a cell forward, and myosin-induced stress (contractility), which retracts the rear. Here we present a simplified physical model of a crawling cell, consisting of a droplet of active polar fluid with contractility throughout, but treadmilling connected to a thin layer near the supporting wall. The model shows a variety of shapes and/or motility regimes, some closely resembling cases seen experimentally. Our work strongly supports the view that cellular motility exploits autonomous physical mechanisms whose operation does not need continuous regulatory effort.

  11. Physical model assisted probability of detection in nondestructive evaluation

    SciTech Connect

    Li, M.; Meeker, W. Q.; Thompson, R. B.

    2011-06-23

    Nondestructive evaluation is used widely in many engineering and industrial areas to detect defects or flaws such as cracks inside parts or structures during manufacturing or for products in service. The standard statistical model is a simple empirical linear regression between the (possibly transformed) signal response variables and the (possibly transformed) explanatory variables. For some applications, such a simple empirical approach is inadequate. An important alternative approach is to use knowledge of the physics of the inspection process to provide information about the underlying relationship between the response and explanatory variables. Use of such knowledge can greatly increase the power and accuracy of the statistical analysis and enable, when needed, proper extrapolation outside the range of the observed explanatory variables. This paper describes a set of physical model-assisted analyses to study the capability of two different ultrasonic testing inspection methods to detect synthetic hard alpha inclusion and flat-bottom hole defects in a titanium forging disk.

  12. Model of cosmology and particle physics at an intermediate scale

    SciTech Connect

    Bastero-Gil, M.; Di Clemente, V.; King, S. F.

    2005-05-15

    We propose a model of cosmology and particle physics in which all relevant scales arise in a natural way from an intermediate string scale. We are led to assign the string scale to the intermediate scale M{sub *}{approx}10{sup 13} GeV by four independent pieces of physics: electroweak symmetry breaking; the {mu} parameter; the axion scale; and the neutrino mass scale. The model involves hybrid inflation with the waterfall field N being responsible for generating the {mu} term, the right-handed neutrino mass scale, and the Peccei-Quinn symmetry breaking scale. The large scale structure of the Universe is generated by the lightest right-handed sneutrino playing the role of a coupled curvaton. We show that the correct curvature perturbations may be successfully generated providing the lightest right-handed neutrino is weakly coupled in the seesaw mechanism, consistent with sequential dominance.

  13. A Linearization Approach for Rational Nonlinear Models in Mathematical Physics

    NASA Astrophysics Data System (ADS)

    Robert, A. Van Gorder

    2012-04-01

    In this paper, a novel method for linearization of rational second order nonlinear models is discussed. In particular, we discuss an application of the δ expansion method (created to deal with problems in Quantum Field Theory) which will enable both the linearization and perturbation expansion of such equations. Such a method allows for one to quickly obtain the order zero perturbation theory in terms of certain special functions which are governed by linear equations. Higher order perturbation theories can then be obtained in terms of such special functions. One benefit to such a method is that it may be applied even to models without small physical parameters, as the perturbation is given in terms of the degree of nonlinearity, rather than any physical parameter. As an application, we discuss a method of linearizing the six Painlevé equations by an application of the method. In addition to highlighting the benefits of the method, we discuss certain shortcomings of the method.

  14. Investigation on thermo physical characteristics of ethylene glycol based Al:ZnO nanofluids

    NASA Astrophysics Data System (ADS)

    R, Kiruba.; George, Ritty; M, Gopalakrishnan.; A, Kingson Solomon Jeevaraj.

    2015-06-01

    The present work describes the experimental aspects of viscosity and thermal conductivity characteristics of nanofluids. Aluminium doped zinc oxide nanostructures were synthesized by chemical precipitation method. Ultrasonic technique is used to disperse the nanostructures in ethylene glycol. Structural and morphological properties of Al doped ZnO nanostructures are characterized using X-ray diffractometer and scanning electron microscopic technique. The effect of concentration and temperature on thermo-physical properties of Al/ZnO nanofluids is also investigated. The experimental results showed there is enhancement in thermal conductivity with rise in temperature which can be utilized for coolant application.

  15. Aqueous foams: a field of investigation at the frontier between chemistry and physics.

    PubMed

    Langevin, Dominique

    2008-03-14

    This paper reviews the properties of aqueous foams. The current state of knowledge is summarized briefly and the interdisciplinary aspects of this field of investigation are emphasized. Many phenomena are controlled by physical laws, but they are highly dependent upon the chemicals used as foam stabilizers: surfactants, polymers, particles. Most of the existing work is related to surfactants and polymer foams, and little is known yet for particle foams although research in this field is becoming popular. This article presents the general concepts used to describe the monolayers and the films and also some of the recent advances being made in this area.

  16. Investigation on thermo physical characteristics of ethylene glycol based Al:ZnO nanofluids

    SciTech Connect

    Kiruba, R. E-mail: drkingson@karunya.edu; George, Ritty; Gopalakrishnan, M.; Kingson Solomon Jeevaraj, A.

    2015-06-24

    The present work describes the experimental aspects of viscosity and thermal conductivity characteristics of nanofluids. Aluminium doped zinc oxide nanostructures were synthesized by chemical precipitation method. Ultrasonic technique is used to disperse the nanostructures in ethylene glycol. Structural and morphological properties of Al doped ZnO nanostructures are characterized using X-ray diffractometer and scanning electron microscopic technique. The effect of concentration and temperature on thermo-physical properties of Al/ZnO nanofluids is also investigated. The experimental results showed there is enhancement in thermal conductivity with rise in temperature which can be utilized for coolant application.

  17. Advancing reservoir operation description in physically based hydrological models

    NASA Astrophysics Data System (ADS)

    Anghileri, Daniela; Giudici, Federico; Castelletti, Andrea; Burlando, Paolo

    2016-04-01

    Last decades have seen significant advances in our capacity of characterizing and reproducing hydrological processes within physically based models. Yet, when the human component is considered (e.g. reservoirs, water distribution systems), the associated decisions are generally modeled with very simplistic rules, which might underperform in reproducing the actual operators' behaviour on a daily or sub-daily basis. For example, reservoir operations are usually described by a target-level rule curve, which represents the level that the reservoir should track during normal operating conditions. The associated release decision is determined by the current state of the reservoir relative to the rule curve. This modeling approach can reasonably reproduce the seasonal water volume shift due to reservoir operation. Still, it cannot capture more complex decision making processes in response, e.g., to the fluctuations of energy prices and demands, the temporal unavailability of power plants or varying amount of snow accumulated in the basin. In this work, we link a physically explicit hydrological model with detailed hydropower behavioural models describing the decision making process by the dam operator. In particular, we consider two categories of behavioural models: explicit or rule-based behavioural models, where reservoir operating rules are empirically inferred from observational data, and implicit or optimization based behavioural models, where, following a normative economic approach, the decision maker is represented as a rational agent maximising a utility function. We compare these two alternate modelling approaches on the real-world water system of Lake Como catchment in the Italian Alps. The water system is characterized by the presence of 18 artificial hydropower reservoirs generating almost 13% of the Italian hydropower production. Results show to which extent the hydrological regime in the catchment is affected by different behavioural models and reservoir

  18. Modelling skin disease: lessons from the worlds of mathematics, physics and computer science.

    PubMed

    Gilmore, Stephen

    2005-05-01

    Theoretical biology is a field that attempts to understand the complex phenomena of life in terms of mathematical and physical principles. Likewise, theoretical medicine employs mathematical arguments and models as a methodology in approaching the complexities of human disease. Naturally, these concepts can be applied to dermatology. There are many possible methods available in the theoretical investigation of skin disease. A number of examples are presented briefly. These include the mathematical modelling of pattern formation in congenital naevi and erythema gyratum repens, an information-theoretic approach to the analysis of genetic networks in autoimmunity, and computer simulations of early melanoma growth. To conclude, an analogy is drawn between the behaviour of well-known physical processes, such as earthquakes, and the spatio-temporal evolution of skin disease. Creating models in skin disease can lead to predictions that can be investigated experimentally or by observation and offer the prospect of unexpected or important insights into pathogenesis.

  19. Explore Physics Beyond the Standard Model with GLAST

    SciTech Connect

    Lionetto, A. M.

    2007-07-12

    We give an overview of the possibility of GLAST to explore theories beyond the Standard Model of particle physics. Among the wide taxonomy we will focus in particular on low scale supersymmetry and theories with extra space-time dimensions. These theories give a suitable dark matter candidate whose interactions and composition can be studied using a gamma ray probe. We show the possibility of GLAST to disentangle such exotic signals from a standard production background.

  20. Qweak, N → Δ, and physics beyond the standard model

    NASA Astrophysics Data System (ADS)

    Leacock, J.

    2014-01-01

    The data-taking phase of the Qweak experiment ended in May of 2012 at the Thomas Jefferson National Accelerator Facility. Qweak aims to measure the weak charge of the proton, Q {/W p }, via parity-violating elastic electron-proton scattering. The expected value of Q {/W p } is fortuitously suppressed, which leads to an increased sensitivity to physics beyond the Standard Model.

  1. Physics Beyond the Standard Model, search for non-perturbative models of electroweak symmetry breaking

    NASA Astrophysics Data System (ADS)

    Cheng, Michael

    2012-03-01

    The Standard Model provides an elegant mechanism for electroweak symmetry breaking (EWSB) via the introduction of a scalar Higgs field. However, the Standard Model Higgs mechanism is not the only way to explain EWSB. A class of models, broadly known as Technicolor, postulates the existence of a new strongly-interacting gauge sector at the TeV scale, coupled to the Standard Model through technifermions charged under electroweak. In technicolor, the spontaneous breaking of chiral symmetry triggers EWSB, with the resulting Goldstone bosons ``eaten'' by the massive W, Z gauge bosons. Because they are strongly-coupled and inherently non-perturbative, numerical lattice gauge theory provides an ideal arena in which technicolor can be explored. The maturation of lattice methods and availability of sufficient computing power has spurred the investigation of technicolor using lattice gauge theory techniques, in particular one variant known as ``walking'' technicolor. A technicolor model that resembles QCD is problematic that it does not satisfy the constraints of precision electro-weak observables, most notably those encapsulated by the Peskin-Takeuchi parameters, as well as the contraints on flavor-changing neutral currents. Walking technicolor is a class of models where the theory is near-conformal, i.e. the gauge coupling runs very slowly (``walks'') over some large range of energy scales. This walking behavior produces a large separation of scales between the natural cut-off for the theory and the EWSB scale, allowing one to naturally generate fermion masses without violating contrainsts on flavor-changing neutral currents. The dynamics of walking theories may also allow it to satisfy the bounds on the Peskin-Takeuchi parameters. We discuss the results of recent lattice calculations that explore the properties of walking technicolor models and the its implications on possible physics beyond the Standard Model.

  2. Physics models in the toroidal transport code PROCTR

    SciTech Connect

    Howe, H.C.

    1990-08-01

    The physics models that are contained in the toroidal transport code PROCTR are described in detail. Time- and space-dependent models are included for the plasma hydrogenic-ion, helium, and impurity densities, the electron and ion temperatures, the toroidal rotation velocity, and the toroidal current profile. Time- and depth-dependent models for the trapped and mobile hydrogenic particle concentrations in the wall and a time-dependent point model for the number of particles in the limiter are also included. Time-dependent models for neutral particle transport, neutral beam deposition and thermalization, fusion heating, impurity radiation, pellet injection, and the radial electric potential are included and recalculated periodically as the time-dependent models evolve. The plasma solution is obtained either in simple flux coordinates, where the radial shift of each elliptical, toroidal flux surface is included to maintain an approximate pressure equilibrium, or in general three-dimensional torsatron coordinates represented by series of helical harmonics. The detailed coupling of the plasma, scrape-off layer, limiter, and wall models through the neutral transport model makes PROCTR especially suited for modeling of recycling and particle control in toroidal plasmas. The model may also be used in a steady-state profile analysis mode for studying energy and particle balances starting with measured plasma profiles.

  3. A Multi-Scale Modeling System with Unified Physics

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo

    2008-01-01

    Numerical cloud models, which are based the non-hydrostatic equations of motion, have been extensively applied to cloud-scale and mesoscale processes during the past four decades. Because cloud-scale dynamics are treated explicitly, uncertainties stemming from convection that have to be parameterized in (hydrostatic) large-scale models are obviated, or at least mitigated, in cloud models. Global models will use the non-hydrostatic framework when their horizontal resolution becomes about 10 km, the theoretical limit for the hydrostatic approximation. This juncture will be reached one to two decades from now. In recent years, exponentially increasing computer power has extended cloud-resolving-mode1 integrations from hours to months, the number of computational grid points from less than a thousand to close to ten million. Three-dimensional models are now more prevalent. Much attention is devoted to precipitating cloud systems where the crucial 1-km scales are resolved in horizontal domains as large as 10,000 km in two-dimensions, and 1,000 x 1,000 km2 in three-dimensions. Cloud resolving models now provide statistical information useful for developing more realistic physically based parameterizations for climate models and numerical weather prediction models. It is also expected that NWP and mesoscale model can be run in grid size similar to cloud resolving model through nesting technique.

  4. On Wiener filtering and the physics behind statistical modeling.

    PubMed

    Marbach, Ralf

    2002-01-01

    The closed-form solution of the so-called statistical multivariate calibration model is given in terms of the pure component spectral signal, the spectral noise, and the signal and noise of the reference method. The "statistical" calibration model is shown to be as much grounded on the physics of the pure component spectra as any of the "physical" models. There are no fundamental differences between the two approaches since both are merely different attempts to realize the same basic idea, viz., the spectrometric Wiener filter. The concept of the application-specific signal-to-noise ratio (SNR) is introduced, which is a combination of the two SNRs from the reference and the spectral data. Both are defined and the central importance of the latter for the assessment and development of spectroscopic instruments and methods is explained. Other statistics like the correlation coefficient, prediction error, slope deficiency, etc., are functions of the SNR. Spurious correlations and other practically important issues are discussed in quantitative terms. Most important, it is shown how to use a priori information about the pure component spectra and the spectral noise in an optimal way, thereby making the distinction between statistical and physical calibrations obsolete and combining the best of both worlds. Companies and research groups can use this article to realize significant savings in cost and time for development efforts.

  5. Causal modeling of secondary science students' intentions to enroll in physics

    NASA Astrophysics Data System (ADS)

    Crawley, Frank E.; Black, Carolyn B.

    The purpose of this study was to explore the utility of the theory of planned behavior model developed by social psychologists for understanding and predicting the behavioral intentions of secondary science students regarding enrolling in physics. In particular, the study used a three-stage causal model to investigate the links from external variables to behavioral, normative, and control beliefs; from beliefs to attitudes, subjective norm, and perceived behavioral control; and from attitudes, subjective norm, and perceived behavioral control to behavioral intentions. The causal modeling method was employed to verify the underlying causes of secondary science students' interest in enrolling physics as predicted in the theory of planned behavior. Data were collected from secondary science students (N = 264) residing in a central Texas city who were enrolled in earth science (8th grade), biology (9th grade), physical science (10th grade), or chemistry (11th grade) courses. Cause-and-effect relationships were analyzed using path analysis to test the direct effects of model variables specified in the theory of planned behavior. Results of this study indicated that students' intention to enroll in a high school physics course was determined by their attitude toward enrollment and their degree of perceived behavioral control. Attitude, subjective norm, and perceived behavioral control were, in turn, formed as a result of specific beliefs that students held about enrolling in physics. Grade level and career goals were found to be instrumental in shaping students' attitude. Immediate family members were identified as major referents in the social support system for enrolling in physics. Course and extracurricular conflicts and the fear of failure were shown to be the primary beliefs obstructing students' perception of control over physics enrollment. Specific recommendations are offered to researchers and practitioners for strengthening secondary school students

  6. Investigations into the physical mechanisms that facilitate transformation hysteresis in shape memory alloys

    NASA Astrophysics Data System (ADS)

    Hamilton, Reginald F.

    Shape Memory Alloys (SMAs) undergo a reversible martensitic transformation (MT) that may be thermal- or stress-induced enabling the recovery of large deformations, up to 12% strain, can be fully recovered, albeit a hysteresis exists. Characterizing the hysteresis for classes of SMAs is essential for their practical application. It is well known that the hysteresis is due to energy dissipative mechanisms, with the primary mechanisms being frictional resistance to interfacial motion and partial plastic accommodation of shape and volume changes. In previous work, however, the origins of potential dissipative mechanisms have not been clarified, and the factors that influence these mechanisms (i.e. external stress fields, matrix strength properties, precipitate microstructure, plastic accommodation, detwinning, etc.) have not been investigated with rigorous experimentation. In this study, an experimental program is designed to address this issue. This comprehensive experimental program, including stress-free thermal cycling, constant load thermal cycling, and constant temperature stress/strain cycling, is undertaken for NiTi, CoNiAl, NiFeGa, and NiMnGa SMAs in the aged and unaged states. The NiFeGa and NiMnGa classes of SMAs undergo martensite to martensite inter-martensitic transformations. The experimental findings characterize the effect of second-phase particles and inter-martensitic transformations on the level of hysteresis. To ascertain physical mechanisms responsible for the hysteresis, in-situ transmission electron microscopy (TEM) analysis provides insight into microstructure features. The results expose the role of frictional resistance and partial plastic accommodation on the observed differential magnitudes of thermal and stress hysteresis. In particular, larger hysteresis magnitudes are mainly attributed to dislocation emissions at the austenite/martensite phase boundary, designated micro-scale plasticity, that lower coherent interface strains, and thus

  7. Investigation of Mental Health in Patients with Medically Unexplained Physical Symptoms‎

    PubMed Central

    Riahi, Frough; Izadi-mazidi, Maryam; Khajeddin, Niloufar; Nasirzadeh, Shahriar; Shafieian, Fatemeh; Helalinasab, Ammar; Deilamani, Mozhgan

    2016-01-01

    Objective: Medically unexplained symptoms are physical symptoms, which cannot be explained by organic ‎causes. This study aimed to investigate mental health in patients with medically unexplained ‎physical symptoms. ‎ Method: One hundred outpatients who were admitted to the Electro Diagnosis Clinic of Imam Khomeini ‎hospital, Ahvaz/Iran, participated in this study. Data were collected using physical examination, ‎paraclinical examinations, and SCL-90-R, and analyzed through multivariate analysis of variance ‎‎ (MANOVA), Chi-square test and Fisher’s exact test. ‎ Results: The findings revealed significant differences between clients with medically explained and ‎unexplained symptoms in obsessive compulsive and somatization (p<0.05). Differences in ‎depression, anxiety, phobia, psychosis, aggression and paranoia were not significant (p>0.05).‎ Conclusion: The present study suggested an association between some psychological problems and somatic ‎symptoms. Therefore, screening for psychological impairments can improve clinical outcomes.‎ PMID:27252765

  8. Investigation of Transmission Line Models for Switching Overvoltages Studies

    NASA Astrophysics Data System (ADS)

    Sadeghkhani, Iman; Ketabi, Abbas; Feuillet, Rene

    2013-06-01

    Overvoltages caused by switching operation of power system equipments might damage some equipment and delay power system restoration. This paper presents a comparison between transmission line (TL) models for overvoltages study and investigates which TL model is most proper for every case study. Both simulation time and accuracy factors of TL models are considered for selecting best TL model. Various cases of switching of transformer, shunt reactor, capacitor bank, and transmission line are investigated and simulation results for a partial of 39-bus New England test system, show that the proposed TL model evaluation increase accuracy and reduce simulation time (accelerate power system restoration) properly.

  9. Experimental investigations of the optical and physical properties of interstellar and lunar dust grains

    NASA Astrophysics Data System (ADS)

    Tankosic, Dragana

    2010-10-01

    Dust grains constitute a major component of matter in the universe. About half of all elements in the interstellar medium (ISM) heavier than helium are in the form of dust. Dust particles are formed in astrophysical environments by processes such as stellar outflows and supernovae. Ejected into the ISM, they lead to the formation of diffuse and dense molecular clouds of gas and dust. The gas and dust in the interstellar clouds undergo a variety of complex physical and chemical evolutionary processes leading to the formation of stars and planetary systems, forming a cosmic dust cycle. Micron/submicron size cosmic dust grains have a significant role in physical and dynamical processes in the galaxy, the ISM, and the interplanetary and planetary environments. Therefore, the knowledge of the physical, optical, and charging properties of the cosmic dust provides valuable information about many issues related to the role of dust in astrophysical environments. An experimental facility based on an electrodynamic balance (EDB) has been developed at NASA- Marshall Space Flight Center (MSFC) for investigation of several different properties and processes of individual, levitated micron/submicron size dust grains in simulated space environments. This dissertation focuses on experimental investigations in the following areas: (1) Radiation pressure on individual micron-sized dust grains; (2) Rotation and alignment of micron-sized dust grains simulating rotation of dust grains in astrophysical environment; (3) Charging of analogs of individual cosmic dust grains and lunar dust grains by UV radiation; (4) Charging of Apollo 11 & 17 lunar dust grains by electron impact simulating the charging of lunar dust by the solar wind plasma. The experimental results obtained on individual micron/submicron-size dust grains in the EDB facility at NASA/MSFC in each of the above four areas were unique and first to be reported. Experimental studies of the physical and optical properties of

  10. Investigation of Atmospheric Recycling Rate from Observation and Model

    NASA Astrophysics Data System (ADS)

    Trammell, J. H.; Jiang, X.; Li, L.; Liang, M.; Zhou, J.; Yung, Y. L.

    2012-12-01

    Precipitation plays an important role in the hydrological cycle on Earth. Based on the long-term (1988-2009) meteorological data sets, our observational study (Li et al., 2011) revealed that the precipitation increased over the wet area (i.e., monthly precipitation > 200 mm) and decreased over the dry area (i.e., monthly precipitation < 50 mm) during the past two decades. The precipitation trend reported in our study is consistent with a "rich-get-richer" mechanism suggested by theoretical studies (Chou and Neelin, 2004; Neelin et al., 2006; Chou et al., 2009). Here, we investigate whether the current atmospheric models can quantitatively capture the characteristics of precipitation from the observational study (Li et al., 2011). Quantitatively simulating the precipitation trend over the globe during the past two decades not only help predict the variation of precipitation in the future but also provide a numerical basis to better understand the physics behind the temporal variation of precipitation. The NASA Goddard Institute for Space Studies (GISS) model is used to look at a historic run of the global precipitation, temperature, and water vapor, in which the historic greenhouse gases are included. We compare the historic simulation from the GISS model with the actual observations provided by the Special Sensor Microwave Imager (SSM/I) and the Global Precipitation Climatology Project (GPCP) (Li et al., 2011). We also compare the historic run with a control run, in which the concentrations of the greenhouse gases are fixed. With the global warming due to the historic greenhouse gases, the historic run precipitation data in the "wet" areas illustrate an increasing trend of precipitation over the wet area, which is consistent with the observational analysis (Li et al., 2011). In contrast, the control run does not show a significant temporal variation in the global temperature and precipitation. The comparison between the historic run and the control run suggests

  11. Investigation on Multi-Physics Simulation-Based Virtual Machining System for Vibratory Finishing of Integrally Bladed Rotors (IBRS)

    NASA Astrophysics Data System (ADS)

    Achiamah-Ampomah, N.; Cheng, Kai

    2016-02-01

    An investigation was carried out to improve the slow surface finishing times of integrally bladed rotors (IBRs) in the aerospace industry. Traditionally they are finished by hand, or more currently by abrasive flow machining. The use of a vibratory finishing technique to improve process times has been suggested; however as a largely empirical process, very few studies have been done to improve and optimize the cycle times, showing that critical and ongoing research is still needed in this area. An extensive review of the literature was carried out, and the findings used to identify the key parameters and model equations which govern the vibratory process. Recommendations were made towards a multi-physics-based simulation model, as well as projections made for the future of vibratory finishing and optimization of surface finishes and cycle times.

  12. Boltzmann-Arrhenius (baz) Model in Physics-Of Problems

    NASA Astrophysics Data System (ADS)

    Suhir, E.; Kang, S.-M.

    2013-05-01

    Boltzmann-Arrhenius-Zhurkov (BAZ) model enables one to obtain a simple, easy-to-use and physically meaningful formula for the evaluation of the probability of failure (PoF) of a material after the given time in operation at the given temperature and under the given stress (not necessarily mechanical). It is shown that the material degradation (aging, damage accumulation, flaw propagation, etc.) can be viewed, when BAZ model is considered, as a Markovian process, and that the BAZ model can be obtained as the steady-state solution to the Fokker-Planck equation in the theory of Markovian processes. It is shown also that the BAZ model addresses the worst and a reasonably conservative situation, when the highest PoF is expected. It is suggested therefore that the transient period preceding the condition addressed by the steady-state BAZ model need not be accounted for in engineering evaluations. However, when there is an interest in understanding the physics of the transient degradation process, the obtained solution to the Fokker-Planck equation can be used for this purpose.

  13. Investigating impacts of chemistry and transport model formulation on model performance at European scale

    NASA Astrophysics Data System (ADS)

    Pirovano, G.; Balzarini, A.; Bessagnet, B.; Emery, C.; Kallos, G.; Meleux, F.; Mitsakou, C.; Nopmongcol, U.; Riva, G. M.; Yarwood, G.

    2012-06-01

    The CAMx and CHIMERE chemistry and transport models were applied over Europe for the year 2006 in the framework of the AQMEII inter-comparison exercise. Model simulations used the same input data set thus allowing model performance evaluation to focus on differences related to model chemistry and physics. Model performance was investigated according to different conditions, such as monitoring station classification and geographical features. An improved evaluation methodology, based on the Wilcoxon statistical test, was implemented to provide objectivity in the comparison of model performance. The models demonstrated similar geographical variations in model performance with just a few exceptions. Both models displayed great performance variability from region to region and within the same region for NO2 and PM10. Station type is relevant mainly for pollutants directly influenced by low level emission sources, such as NO2 and PM10. The analysis of the differences between CAMx and CHIMERE results revealed that both physical and chemical processes influenced the model performance. Particularly, differences in vertical diffusion coefficients (Kz) and 1st layer wind speed can affect the surface concentration of primary compounds, especially for stable conditions. Differently, differences in the vertical profiles of Kz strongly influenced the impact of aloft sources on ground level concentrations of both primary pollutants such as SO2 as well as PM10 compounds. CAMx showed stronger photochemistry than CHIMERE giving rise to higher ozone concentrations that agreed better with observations. Nonetheless, in some areas the more effective photochemistry showed by CAMx actually compensated for an underestimation in the background concentration. Finally, PM10 performance was rather poor for both models in most regions. CAMx performed always better than CHIMERE in terms of bias, while CHIMERE score for correlation was always higher than CAMx. As already mentioned, vertical

  14. Physical and mathematical modeling of antimicrobial photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Bürgermeister, Lisa; López, Fernando Romero; Schulz, Wolfgang

    2014-07-01

    Antimicrobial photodynamic therapy (aPDT) is a promising method to treat local bacterial infections. The therapy is painless and does not cause bacterial resistances. However, there are gaps in understanding the dynamics of the processes, especially in periodontal treatment. This work describes the advances in fundamental physical and mathematical modeling of aPDT used for interpretation of experimental evidence. The result is a two-dimensional model of aPDT in a dental pocket phantom model. In this model, the propagation of laser light and the kinetics of the chemical reactions are described as coupled processes. The laser light induces the chemical processes depending on its intensity. As a consequence of the chemical processes, the local optical properties and distribution of laser light change as well as the reaction rates. The mathematical description of these coupled processes will help to develop treatment protocols and is the first step toward an inline feedback system for aPDT users.

  15. Reduced-Order Modeling: New Approaches for Computational Physics

    NASA Technical Reports Server (NTRS)

    Beran, Philip S.; Silva, Walter A.

    2001-01-01

    In this paper, we review the development of new reduced-order modeling techniques and discuss their applicability to various problems in computational physics. Emphasis is given to methods ba'sed on Volterra series representations and the proper orthogonal decomposition. Results are reported for different nonlinear systems to provide clear examples of the construction and use of reduced-order models, particularly in the multi-disciplinary field of computational aeroelasticity. Unsteady aerodynamic and aeroelastic behaviors of two- dimensional and three-dimensional geometries are described. Large increases in computational efficiency are obtained through the use of reduced-order models, thereby justifying the initial computational expense of constructing these models and inotivatim,- their use for multi-disciplinary design analysis.

  16. Modelling the physics in iterative reconstruction for transmission computed tomography

    PubMed Central

    Nuyts, Johan; De Man, Bruno; Fessler, Jeffrey A.; Zbijewski, Wojciech; Beekman, Freek J.

    2013-01-01

    There is an increasing interest in iterative reconstruction (IR) as a key tool to improve quality and increase applicability of X-ray CT imaging. IR has the ability to significantly reduce patient dose, it provides the flexibility to reconstruct images from arbitrary X-ray system geometries and it allows to include detailed models of photon transport and detection physics, to accurately correct for a wide variety of image degrading effects. This paper reviews discretisation issues and modelling of finite spatial resolution, Compton scatter in the scanned object, data noise and the energy spectrum. Widespread implementation of IR with highly accurate model-based correction, however, still requires significant effort. In addition, new hardware will provide new opportunities and challenges to improve CT with new modelling. PMID:23739261

  17. A physically-based abrasive wear model for composite materials

    SciTech Connect

    Lee, Gun Y.; Dharan, C.K.H.; Ritchie, Robert O.

    2001-05-01

    A simple physically-based model for the abrasive wear of composite materials is presented based on the mechanics and mechanisms associated with sliding wear in soft (ductile) matrix composites containing hard (brittle) reinforcement particles. The model is based on the assumption that any portion of the reinforcement that is removed as wear debris cannot contribute to the wear resistance of the matrix material. The size of this non-contributing portion of the reinforcement is estimated by modeling the three primary wear mechanisms, specifically plowing, interfacial cracking and particle removal. Critical variables describing the role of the reinforcement, such as its relative size and the nature of the matrix/reinforcement interface, are characterized by a single contribution coefficient, C. Predictions are compared with the results of experimental two-body (pin-on drum) abrasive wear tests performed on a model aluminum particulate-reinforced epoxy matrix composite material.

  18. Investigating student communities with network analysis of interactions in a physics learning center

    NASA Astrophysics Data System (ADS)

    Brewe, Eric; Kramer, Laird; Sawtelle, Vashti

    2012-06-01

    Developing a sense of community among students is one of the three pillars of an overall reform effort to increase participation in physics, and the sciences more broadly, at Florida International University. The emergence of a research and learning community, embedded within a course reform effort, has contributed to increased recruitment and retention of physics majors. We utilize social network analysis to quantify interactions in Florida International University’s Physics Learning Center (PLC) that support the development of academic and social integration. The tools of social network analysis allow us to visualize and quantify student interactions and characterize the roles of students within a social network. After providing a brief introduction to social network analysis, we use sequential multiple regression modeling to evaluate factors that contribute to participation in the learning community. Results of the sequential multiple regression indicate that the PLC learning community is an equitable environment as we find that gender and ethnicity are not significant predictors of participation in the PLC. We find that providing students space for collaboration provides a vital element in the formation of a supportive learning community.

  19. An experimental investigation of the flow physics of high-lift systems

    NASA Technical Reports Server (NTRS)

    Thomas, Flint O.; Nelson, R. C.

    1995-01-01

    This progress report is a series of overviews outlining experiments on the flow physics of confluent boundary layers for high-lift systems. The research objectives include establishing the role of confluent boundary layer flow physics in high-lift production; contrasting confluent boundary layer structures for optimum and non-optimum C(sub L) cases; forming a high quality, detailed archival data base for CFD/modelling; and examining the role of relaminarization and streamline curvature. Goals of this research include completing LDV study of an optimum C(sub L) case; performing detailed LDV confluent boundary layer surveys for multiple non-optimum C(sub L) cases; obtaining skin friction distributions for both optimum and non-optimum C(sub L) cases for scaling purposes; data analysis and inner and outer variable scaling; setting-up and performing relaminarization experiments; and a final report establishing the role of leading edge confluent boundary layer flow physics on high-lift performance.

  20. Investigating students’ mental models about the nature of light in different contexts

    NASA Astrophysics Data System (ADS)

    Özcan, Özgür

    2015-11-01

    In this study, we investigated pre-service physics teachers’ mental models of light in different contexts, such as blackbody radiation, the photoelectric effect and the Compton effect. The data collected through the paper-and-pencil questionnaire (PPQ) were analyzed both quantitatively and qualitatively. Sampling of this study consists of a total of 110 physics education students who were taking a modern physics course at two different state universities in Turkey. As a result, three mental models, which were called the beam ray model (BrM), hybrid model (HM) and particle model (PM), were being used by the students while explaining these phenomena. The most model fluctuation was seen in HM and BrM. In addition, some students were in a mixed-model state where they use multiple mental models in explaining a phenomenon and used these models inconsistently. On the other hand, most of the students who used the particle model can be said to be in a pure model state.

  1. An investigation into the effectiveness of problem-based learning in a physical chemistry laboratory course

    NASA Astrophysics Data System (ADS)

    Gürses, Ahmet; Açıkyıldız, Metin; Doğar, Çetin; Sözbilir, Mustafa

    2007-04-01

    The aim of this study was to investigate the effectiveness of a problem-based learning (PBL) approach in a physical chemistry laboratory course. The parameters investigated were students’ attitudes towards a chemistry laboratory course, scientific process skills of students and their academic achievement. The design of the study was one group pre-test post-test. Four experiments, covering the topics adsorption, viscosity, surface tension and conductivity were performed using a PBL approach in the fall semester of the 2003/04 academic year at Kazim Karabekir Education Faculty of Atatürk University. Each experiment was done over a three week period. A total of 40 students, 18 male and 22 female, participated in the study. Students took the Physical Chemistry Laboratory Concept Test (PCLCT), Attitudes towards Chemistry Laboratory (ATCL) questionnaire and Science Process Skills Test (SPST) as pre and post-tests. In addition, the effectiveness of the PBL approach was also determined through four different scales; Scales Specific to Students’ Views of PBL. A statistically significant difference between the students’ academic achievement and scientific process skills at p

  2. Reference earth orbital research and applications investigations (blue book). Volume 3: Physics

    NASA Technical Reports Server (NTRS)

    1971-01-01

    The definition of physics experiments to be conducted aboard the space station is presented. The four functional program elements are: (1) space physics research laboratory, (2) plasma physics and environmental perturbation laboratory, (3) cosmic ray physics laboratory, and (4) physics and chemistry laboratory. The experiments to be conducted by each facility are defined and the crew member requirements to accomplish the experiments are presented.

  3. Possibilities: A framework for modeling students' deductive reasoning in physics

    NASA Astrophysics Data System (ADS)

    Gaffney, Jonathan David Housley

    Students often make errors when trying to solve qualitative or conceptual physics problems, and while many successful instructional interventions have been generated to prevent such errors, the process of deduction that students use when solving physics problems has not been thoroughly studied. In an effort to better understand that reasoning process, I have developed a new framework, which is based on the mental models framework in psychology championed by P. N. Johnson-Laird. My new framework models how students search possibility space when thinking about conceptual physics problems and suggests that errors arise from failing to flesh out all possibilities. It further suggests that instructional interventions should focus on making apparent those possibilities, as well as all physical consequences those possibilities would incur. The possibilities framework emerged from the analysis of data from a unique research project specifically invented for the purpose of understanding how students use deductive reasoning. In the selection task, participants were given a physics problem along with three written possible solutions with the goal of identifying which one of the three possible solutions was correct. Each participant was also asked to identify the errors in the incorrect solutions. For the study presented in this dissertation, participants not only performed the selection task individually on four problems, but they were also placed into groups of two or three and asked to discuss with each other the reasoning they used in making their choices and attempt to reach a consensus about which solution was correct. Finally, those groups were asked to work together to perform the selection task on three new problems. The possibilities framework appropriately models the reasoning that students use, and it makes useful predictions about potentially helpful instructional interventions. The study reported in this dissertation emphasizes the useful insight the

  4. A Physical Model of the Metric Expansion of Space

    NASA Astrophysics Data System (ADS)

    Laubenstein, John

    2010-02-01

    At the heart of IWPD's Scale Metrics (ISM) theory is the realization that any orthogonal relationship may be equivalently expressed as a linear relationship multiplied by a mathematical scalar. This has significance in the relationship of a worldline to its 4-Velocity and observed 3-Velocity, as well as in understanding the divergence between energy and momentum as invariant mass increases. Spacetime may be depicted by taking the time dimension within four-dimensional spacetime and rotating it until it becomes embedded as a line segment (or ring) within the three spatial dimensions. This allows velocity and momentum to be determined based upon a linear subtraction of physical entities multiplied by a mathematical scalar (X). We will provide evidence supporting the mathematical and physical significance of this scaling factor along with the benefits of ISM theory. This model provides a physical explanation of the metric expansion of space and defines the initial singularity present at the earliest moment of the universe. ISM theory addresses many of the current challenges in physics and makes predictions that are testable with technologies currently in place. )

  5. Modeling Physical Systems Using Vensim PLE Systems Dynamics Software

    NASA Astrophysics Data System (ADS)

    Widmark, Stephen

    2012-02-01

    Many physical systems are described by time-dependent differential equations or systems of such equations. This makes it difficult for students in an introductory physics class to solve many real-world problems since these students typically have little or no experience with this kind of mathematics. In my high school physics classes, I address this problem by having my students use a variety of software solutions to model physical systems described by differential equations. These include spreadsheets, applets, software my students themselves create, and systems dynamics software. For the latter, cost is often the main issue in choosing a solution for use in a public school and so I researched no-cost software. I found Sphinx SD,2OptiSim,3 Systems Dynamics,4 Simile (Trial Edition),5 and Vensim PLE.6 In evaluating each of these solutions, I looked for the fewest restrictions in the license for educational use, ease of use by students, power, and versatility. In my opinion, Vensim PLE best fulfills these criteria.7

  6. A formal hybrid modeling scheme for handling discontinuities in physical system models

    SciTech Connect

    Mosterman, P.J.; Biswas, G.

    1996-12-31

    Physical systems are by nature continuous, but often exhibit nonlinearities that make behavior generation complex and hard to analyze. Complexity is often reduced by linearizing model constraints and by abstracting the time scale for behavior generation. In either case, the physical components are modeled to operate in multiple modes, with abrupt changes between modes. This paper discusses a hybrid modeling methodology and analysis algorithms that combine continuous energy flow modeling and localized discrete signal flow modeling to generate complex, multi-mode behavior in a consistent and correct manner. Energy phase space analysis is employed to demonstrate the correctness of the algorithm, and the reachability of a continuous mode.

  7. Dynamic modeling, property investigation, and adaptive controller design of serial robotic manipulators modeled with structural compliance

    NASA Technical Reports Server (NTRS)

    Tesar, Delbert; Tosunoglu, Sabri; Lin, Shyng-Her

    1990-01-01

    Research results on general serial robotic manipulators modeled with structural compliances are presented. Two compliant manipulator modeling approaches, distributed and lumped parameter models, are used in this study. System dynamic equations for both compliant models are derived by using the first and second order influence coefficients. Also, the properties of compliant manipulator system dynamics are investigated. One of the properties, which is defined as inaccessibility of vibratory modes, is shown to display a distinct character associated with compliant manipulators. This property indicates the impact of robot geometry on the control of structural oscillations. Example studies are provided to illustrate the physical interpretation of inaccessibility of vibratory modes. Two types of controllers are designed for compliant manipulators modeled by either lumped or distributed parameter techniques. In order to maintain the generality of the results, neither linearization is introduced. Example simulations are given to demonstrate the controller performance. The second type controller is also built for general serial robot arms and is adaptive in nature which can estimate uncertain payload parameters on-line and simultaneously maintain trajectory tracking properties. The relation between manipulator motion tracking capability and convergence of parameter estimation properties is discussed through example case studies. The effect of control input update delays on adaptive controller performance is also studied.

  8. The physical theory and propagation model of THz atmospheric propagation

    NASA Astrophysics Data System (ADS)

    Wang, R.; Yao, J. Q.; Xu, D. G.; Wang, J. L.; Wang, P.

    2011-02-01

    Terahertz (THz) radiation is extensively applied in diverse fields, such as space communication, Earth environment observation, atmosphere science, remote sensing and so on. And the research on propagation features of THz wave in the atmosphere becomes more and more important. This paper firstly illuminates the advantages and outlook of THz in space technology. Then it introduces the theoretical framework of THz atmospheric propagation, including some fundamental physical concepts and processes. The attenuation effect (especially the absorption of water vapor), the scattering of aerosol particles and the effect of turbulent flow mainly influence THz atmosphere propagation. Fundamental physical laws are illuminated as well, such as Lamber-beer law, Mie scattering theory and radiative transfer equation. The last part comprises the demonstration and comparison of THz atmosphere propagation models like Moliere(V5), SARTre and AMATERASU. The essential problems are the deep analysis of physical mechanism of this process, the construction of atmospheric propagation model and databases of every kind of material in the atmosphere, and the standardization of measurement procedures.

  9. The physical model for research of behavior of grouting mixtures

    NASA Astrophysics Data System (ADS)

    Hajovsky, Radovan; Pies, Martin; Lossmann, Jaroslav

    2016-06-01

    The paper deals with description of physical model designed for verification of behavior of grouting mixtures when applied below underground water level. Described physical model has been set up to determine propagation of grouting mixture in a given environment. Extension of grouting in this environment is based on measurement of humidity and temperature with the use of combined sensors located within preinstalled special measurement probes around grouting needle. Humidity was measured by combined capacity sensor DTH-1010, temperature was gathered by a NTC thermistor. Humidity sensors measured time when grouting mixture reached sensor location point. NTC thermistors measured temperature changes in time starting from initial of injection. This helped to develop 3D map showing the distribution of grouting mixture through the environment. Accomplishment of this particular measurement was carried out by a designed primary measurement module capable of connecting 4 humidity and temperature sensors. This module also takes care of converting these physical signals into unified analogue signals consequently brought to the input terminals of analogue input of programmable automation controller (PAC) WinPAC-8441. This controller ensures the measurement itself, archiving and visualization of all data. Detail description of a complex measurement system and evaluation in form of 3D animations and graphs is supposed to be in a full paper.

  10. Advanced Ground Systems Maintenance Physics Models For Diagnostics Project

    NASA Technical Reports Server (NTRS)

    Perotti, Jose M.

    2015-01-01

    The project will use high-fidelity physics models and simulations to simulate real-time operations of cryogenic and systems and calculate the status/health of the systems. The project enables the delivery of system health advisories to ground system operators. The capability will also be used to conduct planning and analysis of cryogenic system operations. This project will develop and implement high-fidelity physics-based modeling techniques tosimulate the real-time operation of cryogenics and other fluids systems and, when compared to thereal-time operation of the actual systems, provide assessment of their state. Physics-modelcalculated measurements (called “pseudo-sensors”) will be compared to the system real-timedata. Comparison results will be utilized to provide systems operators with enhanced monitoring ofsystems' health and status, identify off-nominal trends and diagnose system/component failures.This capability can also be used to conduct planning and analysis of cryogenics and other fluidsystems designs. This capability will be interfaced with the ground operations command andcontrol system as a part of the Advanced Ground Systems Maintenance (AGSM) project to helpassure system availability and mission success. The initial capability will be developed for theLiquid Oxygen (LO2) ground loading systems.

  11. Simplified Physics Based Models Research Topical Report on Task #2

    SciTech Connect

    Mishra, Srikanta; Ganesh, Priya

    2014-10-31

    We present a simplified-physics based approach, where only the most important physical processes are modeled, to develop and validate simplified predictive models of CO2 sequestration in deep saline formation. The system of interest is a single vertical well injecting supercritical CO2 into a 2-D layered reservoir-caprock system with variable layer permeabilities. We use a set of well-designed full-physics compositional simulations to understand key processes and parameters affecting pressure propagation and buoyant plume migration. Based on these simulations, we have developed correlations for dimensionless injectivity as a function of the slope of fractional-flow curve, variance of layer permeability values, and the nature of vertical permeability arrangement. The same variables, along with a modified gravity number, can be used to develop a correlation for the total storage efficiency within the CO2 plume footprint. Similar correlations are also developed to predict the average pressure within the injection reservoir, and the pressure buildup within the caprock.

  12. Physical and numerical investigations of channel bar response to hydrograph form

    NASA Astrophysics Data System (ADS)

    Kenworthy, M.; Yager, E.; Yarnell, S. M.; Merritt, D.

    2013-12-01

    Physical and numerical modeling of river channel morphology often consider the influence of a single discharge or a series of individual discharges assumed to be in normal, steady conditions. However, the rate of change between these discharges may also affect channel morphology. Rapid flooding has been linked to poorly sorted, less armored beds compared to more gradual floods, but the influence on morphology is rarely considered. In addition, installation of vegetation is common in restoration projects though it is not always clear how this will impact morphological features such as bars. Here we present results from a set of flume experiments and 2D modeling designed to investigate the influence of hydrograph shape and vegetation on the morphology of a forced bar in sand-bed channel. Flume experiments were conducted in the Outdoor Stream Lab at Saint Anthony Falls Laboratory, Minneapolis, MN. We ran three falling limb only hydrographs with different recession rates (10, 30, and 70%). Minimum discharge, total volumetric water discharge, and estimated sediment transport capacity were held within 10% between runs. The ratio of sediment supply to estimated transport capacity was also held constant at all times. The 10% run peaked at 150 L/s, while the 30% and 70% runs peaked at 284 L/s. The 30 and 70% runs were repeated with vegetation (Juncus and Carex) that mimicked vegetation established at approximately bankful height. Similar initial conditions for all runs were established by running the flume to equilibrium at constant flow and feed rates. Detailed bar topography/bathymetry data were collected before, during, and following each run. Bar morphology at the conclusion of recession hydrographs indicated that bar development declines as recession rate increases. Both with and without vegetation, the faster recessions resulted in bar morphology that was less distinct. This observation is supported by bar-top widths and areas that both declined as recession rate

  13. Numerical modeling of piezoelectric transducers using physical parameters.

    PubMed

    Cappon, Hans; Keesman, Karel J

    2012-05-01

    Design of ultrasonic equipment is frequently facilitated with numerical models. These numerical models, however, need a calibration step, because usually not all characteristics of the materials used are known. Characterization of material properties combined with numerical simulations and experimental data can be used to acquire valid estimates of the material parameters. In our design application, a finite element (FE) model of an ultrasonic particle separator, driven by an ultrasonic transducer in thickness mode, is required. A limited set of material parameters for the piezoelectric transducer were obtained from the manufacturer, thus preserving prior physical knowledge to a large extent. The remaining unknown parameters were estimated from impedance analysis with a simple experimental setup combined with a numerical optimization routine using 2-D and 3-D FE models. Thus, a full set of physically interpretable material parameters was obtained for our specific purpose. The approach provides adequate accuracy of the estimates of the material parameters, near 1%. These parameter estimates will subsequently be applied in future design simulations, without the need to go through an entire series of characterization experiments. Finally, a sensitivity study showed that small variations of 1% in the main parameters caused changes near 1% in the eigenfrequency, but changes up to 7% in the admittance peak, thus influencing the efficiency of the system. Temperature will already cause these small variations in response; thus, a frequency control unit is required when actually manufacturing an efficient ultrasonic separation system.

  14. Validation of Geant4 hadronic physics models at intermediate energies

    NASA Astrophysics Data System (ADS)

    Banerjee, Sunanda; Geant4 Hadronic Group

    2010-04-01

    GEANT4 provides a number of physics models at intermediate energies (corresponding to incident momenta in the range 1-20 GeV/c). Recently, these models have been validated with existing data from a number of experiments: (a) inclusive proton and neutron production with a variety of beams (π-, π+, p) at different energies between 1 and 9 GeV/c on a number of nuclear targets (from beryllium to uranium); (2) inclusive pion/kaon/proton production from 14.6 GeV/c proton beams on nuclear targets (from beryllium to gold); (3) inclusive pion production from pion beams between 3-13 GeV/c on a number of nuclear targets (from beryllium to lead). The results of simulation/data comparison for different GEANT4 models are discussed in the context of validating the models and determining their usage in physics lists for high energy application. Due to the increasing number of validations becoming available, and the requirement that they be done at regular intervals corresponding to the GEANT4 release schedule, automated methods of validation are being developed.

  15. UQ-Guided Selection of Physical Parameterizations in Climate Models

    NASA Astrophysics Data System (ADS)

    Lucas, D. D.; Debusschere, B.; Ghan, S.; Rosa, D.; Bulaevskaya, V.; Anderson, G. J.; Chowdhary, K.; Qian, Y.; Lin, G.; Larson, V. E.; Zhang, G. J.; Randall, D. A.

    2015-12-01

    Given two or more parameterizations that represent the same physical process in a climate model, scientists are sometimes faced with difficult decisions about which scheme to choose for their simulations and analysis. These decisions are often based on subjective criteria, such as "which scheme is easier to use, is computationally less expensive, or produces results that look better?" Uncertainty quantification (UQ) and model selection methods can be used to objectively rank the performance of different physical parameterizations by increasing the preference for schemes that fit observational data better, while at the same time penalizing schemes that are overly complex or have excessive degrees-of-freedom. Following these principles, we are developing a perturbed-parameter UQ framework to assist in the selection of parameterizations for a climate model. Preliminary results will be presented on the application of the framework to assess the performance of two alternate schemes for simulating tropical deep convection (CLUBB-SILHS and ZM-trigmem) in the U.S. Dept. of Energy's ACME climate model. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344, is supported by the DOE Office of Science through the Scientific Discovery Through Advanced Computing (SciDAC), and is released as LLNL-ABS-675799.

  16. Diastolic filling in a physical model of obstructive hypertrophic cardiomyopathy

    NASA Astrophysics Data System (ADS)

    Schovanec, Joseph; Samaee, Milad; Lai, Hong Kuan; Santhanakrishnan, Arvind

    2015-11-01

    Hypertrophic Cardiomyopathy (HCM) is an inherited heart disease that affects as much as one in 500 individuals, and is the most common cause of sudden death in young athletes. The myocardium becomes abnormally thick in HCM and deforms the internal geometry of the left ventricle (LV). Previous studies have shown that a vortex is formed during diastolic filling, and further that the dilated LV morphology seen in systolic heart failure results in altering the filling vortex from elliptical to spherical shape. We have also previously shown that increasing LV wall stiffness decreases the filling vortex circulation. However, alterations to intraventricular filling fluid dynamics due to an obstructive LV morphology and locally elevated wall stiffness (in the hypertrophied region) have not been previously examined from a mechanistic standpoint. We conducted an experimental study using an idealized HCM physical model and compared the intraventricular flow fields obtained from 2D PIV to a baseline LV physical model with lower wall stiffness and anatomical geometry. The obstruction in the HCM model leads to earlier breakdown of the filling vortex as compared to the anatomical LV. Intraventricular filling in both models under increased heart rates will be discussed.

  17. Coupled model of physical and biological processes affecting maize pollination

    NASA Astrophysics Data System (ADS)

    Arritt, R.; Westgate, M.; Riese, J.; Falk, M.; Takle, E.

    2003-04-01

    Controversy over the use of genetically modified (GM) crops has led to increased interest in evaluating and controlling the potential for inadvertent outcrossing in open-pollinated crops such as maize. In response to this problem we have developed a Lagrangian model of pollen dispersion as a component of a coupled end-to-end (anther to ear) physical-biological model of maize pollination. The Lagrangian method is adopted because of its generality and flexibility: first, the method readily accommodates flow fields of arbitrary complexity; second, each element of the material being transported can be identified by its source, time of release, or other properties of interest. The latter allows pollen viability to be estimated as a function of such factors as travel time, temperature, and relative humidity, so that the physical effects of airflow and turbulence on pollen dispersion can be considered together with the biological aspects of pollen release and viability. Predicted dispersion of pollen compares well both to observations and to results from a simpler Gaussian plume model. Ability of the Lagrangian model to handle complex air flows is demonstrated by application to pollen dispersion in the vicinity of an agricultural shelter belt. We also show results indicating that pollen viability can be quantified by an "aging function" that accounts for temperature, humidity, and time of exposure.

  18. Modeling Feedbacks Between Individual Human Decisions and Hydrology Using Interconnected Physical and Social Models

    NASA Astrophysics Data System (ADS)

    Murphy, J.; Lammers, R. B.; Proussevitch, A. A.; Ozik, J.; Altaweel, M.; Collier, N. T.; Alessa, L.; Kliskey, A. D.

    2014-12-01

    The global hydrological cycle intersects with human decision making at multiple scales, from dams and irrigation works to the taps in individuals' homes. Residential water consumers are commonly encouraged to conserve; these messages are heard against a background of individual values and conceptions about water quality, uses, and availability. The degree to which these values impact the larger-hydrological dynamics, the way that changes in those values have impacts on the hydrological cycle through time, and the feedbacks by which water availability and quality in turn shape those values, are not well explored. To investigate this domain we employ a global-scale water balance model (WBM) coupled with a social-science-grounded agent-based model (ABM). The integration of a hydrological model with an agent-based model allows us to explore driving factors in the dynamics in coupled human-natural systems. From the perspective of the physical hydrologist, the ABM offers a richer means of incorporating the human decisions that drive the hydrological system; from the view of the social scientist, a physically-based hydrological model allows the decisions of the agents to play out against constraints faithful to the real world. We apply the interconnected models to a study of Tucson, Arizona, USA, and its role in the larger Colorado River system. Our core concept is Technology-Induced Environmental Distancing (TIED), which posits that layers of technology can insulate consumers from direct knowledge of a resource. In Tucson, multiple infrastructure and institutional layers have arguably increased the conceptual distance between individuals and their water supply, offering a test case of the TIED framework. Our coupled simulation allows us to show how the larger system transforms a resource with high temporal and spatial variability into a consumer constant, and the effects of this transformation on the regional system. We use this to explore how pricing, messaging, and

  19. Physics-based prognostic modelling of filter clogging phenomena

    NASA Astrophysics Data System (ADS)

    Eker, Omer F.; Camci, Fatih; Jennions, Ian K.

    2016-06-01

    In industry, contaminant filtration is a common process to achieve a desired level of purification, since contaminants in liquids such as fuel may lead to performance drop and rapid wear propagation. Generally, clogging of filter phenomena is the primary failure mode leading to the replacement or cleansing of filter. Cascading failures and weak performance of the system are the unfortunate outcomes due to a clogged filter. Even though filtration and clogging phenomena and their effects of several observable parameters have been studied for quite some time in the literature, progression of clogging and its use for prognostics purposes have not been addressed yet. In this work, a physics based clogging progression model is presented. The proposed model that bases on a well-known pressure drop equation is able to model three phases of the clogging phenomena, last of which has not been modelled in the literature yet. In addition, the presented model is integrated with particle filters to predict the future clogging levels and to estimate the remaining useful life of fuel filters. The presented model has been implemented on the data collected from an experimental rig in the lab environment. In the rig, pressure drop across the filter, flow rate, and filter mesh images are recorded throughout the accelerated degradation experiments. The presented physics based model has been applied to the data obtained from the rig. The remaining useful lives of the filters used in the experimental rig have been reported in the paper. The results show that the presented methodology provides significantly accurate and precise prognostic results.

  20. Physical models for the source of Lascar's harmonic tremor

    NASA Astrophysics Data System (ADS)

    Hellweg, M.

    2000-08-01

    Over an 18 h interval in April 1994, the tremor at Lascar volcano, Chile, was characterized by a spectrum with narrow peaks at a fundamental freqency of about 0.63 Hz and more than 25 overtones at exact integer multiples. This harmonic tremor was recorded at four three-component, high-dynamic range stations during the deployment of the Proyecto de Investigación Sismológica de la Cordillera Occidental 94 (PISCO'94). Usually this tremor's source is modeled as the resonance of a fluid-filled crack or organ pipe-like structure in the volcano. The resonance of a real, physical structure, however, can produce neither as many overtones nor such exact multiples as those observed in the harmonic tremor at Lascar. Harmonics also occur in a spectrum if the source signal is repetitive but nonsinusoidal. Fluid dynamics offers at least three realistic source models for harmonic tremor which produce repetitive, nonsinusoidal waveforms: the release of gas through a very small outlet (the soda bottle model), slug flow in a narrow conduit, and von Kármán vortices produced at obstacles. These models represent different flow regimes, each with its own characteristic range of Reynolds numbers. For each model the fundamental frequency of the tremor is related to the Reynolds number for the flow. Combining the Reynolds numbers for each model with typical kinematic viscosities for the possible fluids present in a volcano—magma, water, steam, air or some combination, at appropriate temperatures and pressures—provides limits on such physical parameters of the volcano as the dimensions of the flow conduit and the flow velocity of the fluid generating the tremor. If any single one of these three models is actually the process in the volcano which generates harmonic tremor, then the tremor is caused by movements of water or gases in the hydrothermal system near the volcano's surface.

  1. Physical model of bathymetric effects on the Antarctic circumpolar current

    SciTech Connect

    Boyer, D.L.; Ruirong Chen; Lijun Tao ); Davies, P.A. )

    1993-02-15

    Laboratory experiments were conducted to simulate some of the effects of the bathymetry of the southern ocean on the physical characteristics of the Antarctic Circumpolar Current (ACC). An idealized zonal wind stress, which varied inversely with the distance from the model Antarctic continent, was simulated in the laboratory model by a radially inward sink-source flow in a thin layer along the surface of the circular test cell. The present model, however, has the limitation of not accounting for such factors as the longitudinal variations in the wind shear and the decrease in wind stress on approaching the Antarctic continent from the north. Planetary beta effects were neglected because the topographic beta term can be shown to dominate over large portions of the model area. The neglect of beta effects is also a limitation of the model. In spite of these limitations, however, the simulations of the physical model for both the homogeneous and linearly stratified cases were shown to be in good agreement with observations of the ACC. These include well-defined strong currents along the mid-ocean ridge; strong perturbations in the vicinity of the Macquarie Ridge, Campbell Plateau, and Kerguelen Gaussberg Plateau; strong meridional transport to the east of the Drake Passage; and anomalies to the south (wave troughs) and to the north (wave ridges) of the main circumpolar current over ocean basins and mountain ridges, respectively. It was shown that the Eltanin and Udintsev fracture zones in the vicinity of 135[degrees]W are important factors in directing the ACC eastward across the Southeast Pacific Basin to the Drake Passage. The estimated volume transports through the Drake Passage based on the model results are in fair agreement with oceanic observations. Estimates of the spin-up time of the system for homogeneous and stratified cases have been provided. 28 refs., 21 figs., 1 tab.

  2. The nature and role of physical models in enhancing sixth grade students' mental models of groundwater and groundwater processes

    NASA Astrophysics Data System (ADS)

    Duffy, Debra Lynne Foster

    Through a non-experimental descriptive and comparative mixed-methods approach, this study investigated the experiences of sixth grade earth science students with groundwater physical models through an extended SE learning cycle format. The data collection was based on a series of quantitative and qualitative research tools intended to investigate students' ideas and changes in ideas rather than measure their achievement. The measures included a groundwater survey, classroom observations, and one-on-one follow-up student interviews for triangulation of data sources. The research was carried out at a K-12 independent school in eastern Virginia using two classes of sixth grade earth science students (n=30). The findings suggest that physical models help students identify the components porosity and permeability with respect to water flow in groundwater systems. Higher levels of system thinking were best demonstrated in model components that allowed students to experience groundwater pollution activities and pumping groundwater wells. However, the results also indicated that due to model constraints, students can develop misconceptions during the use of physical models, specifically more complex physical models as in the Groundwater Exploration Activity Model. A pure discovery learning format while using physical models without guidance or formative assessment probes can lead to misconceptions about groundwater processes as well as confusion between model attributes and real world groundwater systems. The implications of this study relate directly to the inclusion of groundwater in the new national science standards released in 2011; A Framework for K-12 Science Standard; Practices, Crosscutting Concepts, and Core Ideas (NRC, 2011). The new national standards, as in other educational reform efforts, will have the ability to affect curricular and instructional strategies in science education. From the results of this study, it was concluded that best practices for using

  3. [Investigations in dynamics of gauge theories in theoretical particle physics]. [Virginia Polytechnic Institute State Univ. , Blacksburg

    SciTech Connect

    Not Available

    1993-01-01

    The major theme of the theoretical physics research conducted under DOE support over the past several years has been within the rubric of the standard model, and concerned the interplay between symmetries and dynamics. The research was thus carried out mostly in the context of gauge field theories, and usually in the presence of chiral fermions. Dynamical symmetry breaking was examined both from the point of view of perturbation theory, as well as from non-perturbative techniques associated with certain characteristic features of specific theories. Among the topics of research were: the implications of abelian and non-abelian anomalies on the spectrum and possible dynamical symmetry breaking in any theory, topological and conformal properties of quantum fields in two and higher dimensions, the breaking of global chiral symmetries by vector-like gauge theories such as QCD, the phenomenological implications of a strongly interacting Higgs sector in the standard model, and the application of soliton ideas to the physics to be explored at the SSC.

  4. Overwriting information: Correlations, physical costs, and environment models

    NASA Astrophysics Data System (ADS)

    Anderson, Neal G.

    2012-03-01

    In this sequel to our previous study of the entropic and energetic costs of information erasure [N.G. Anderson, Phys. Lett. A 372 (2008) 5552], we consider direct overwriting of classical information encoded in a quantum-mechanical memory system interacting with a heat bath. Lower bounds on physical costs of overwriting - in both “single-shot” and “sequential” overwriting scenarios - are obtained from globally unitary quantum dynamics and entropic inequalities alone, all within a referential approach that grounds information content in correlations between physical system states. A heterogeneous environment model, required for consistent treatment of sequential overwriting, is introduced and used to establish and relate bounds for various cases.

  5. Fluid transport processes within sea ice: towards physically derived models

    NASA Astrophysics Data System (ADS)

    Wells, A. J.; Wettlaufer, J. S.; Orszag, S.

    2012-12-01

    Rather than being an impermeable solid barrier, young sea ice forms a porous matrix of ice crystals through which the interstitial brine can flow. Gravity drainage of dense brine is of particular importance in young sea ice, with the resulting fluid flow redistributing heat, salt, and passive tracers through the ice and controlling exchanges with the ocean. Hence, an understanding of this buoyancy-driven flow is critical for quantifying ice-ocean tracer fluxes, biogeochemical cycles, and evolution of the salinity-dependent material properties of ice that influence growth and decay. We use mushy layer theory, which describes the thermodynamics of the relevant multiphase flow, simulations and analogue experiments to provide insight into these processes. The approach provides a structure to evaluate ad-hoc parameterizations of brine drainage for consistency with the underlying physics. The resulting theoretical framework points towards a bottom-up approach to deriving models via a homogenization of the underlying physical processes.

  6. Dynamic modeling of physical phenomena for PRAs using neural networks

    SciTech Connect

    Benjamin, A.S.; Brown, N.N.; Paez, T.L.

    1998-04-01

    In most probabilistic risk assessments, there is a set of accident scenarios that involves the physical responses of a system to environmental challenges. Examples include the effects of earthquakes and fires on the operability of a nuclear reactor safety system, the effects of fires and impacts on the safety integrity of a nuclear weapon, and the effects of human intrusions on the transport of radionuclides from an underground waste facility. The physical responses of the system to these challenges can be quite complex, and their evaluation may require the use of detailed computer codes that are very time consuming to execute. Yet, to perform meaningful probabilistic analyses, it is necessary to evaluate the responses for a large number of variations in the input parameters that describe the initial state of the system, the environments to which it is exposed, and the effects of human interaction. Because the uncertainties of the system response may be very large, it may also be necessary to perform these evaluations for various values of modeling parameters that have high uncertainties, such as material stiffnesses, surface emissivities, and ground permeabilities. The authors have been exploring the use of artificial neural networks (ANNs) as a means for estimating the physical responses of complex systems to phenomenological events such as those cited above. These networks are designed as mathematical constructs with adjustable parameters that can be trained so that the results obtained from the networks will simulate the results obtained from the detailed computer codes. The intent is for the networks to provide an adequate simulation of the detailed codes over a significant range of variables while requiring only a small fraction of the computer processing time required by the detailed codes. This enables the authors to integrate the physical response analyses into the probabilistic models in order to estimate the probabilities of various responses.

  7. The Standard Model as a 2T-Physics Theory

    NASA Astrophysics Data System (ADS)

    Bars, I.

    2007-04-01

    New developments in 2T-physics, that connect 2T-physics field theory directly to the real world, are reported in this talk. An action is proposed in field theory in 4+2 dimensions which correctly reproduces the Standard Model (SM) in 3+1 dimensions (and no junk). Everything that is known to work in the SM still works in the emergent 3+1 theory, but some of the problems of the SM get resolved. The resolution is due to new restrictions on interactions inherited from 4+2 dimensions that lead to some interesting physics and new points of view not discussed before in 3+1 dimensions. In particular the strong CP violation problem is resolved without an axion, and the electro-weak symmetry breakdown that generates masses requires the participation of the dilaton, thus relating the electro-weak phase transition to other phase transitions (such as evolution of the universe, vacuum selection in string theory, etc.) that also require the participation of the dilaton. The underlying principle of 2T-physics is the local symmetry Sp(2,R) under which position and momentum become indistinguishable at any instant. This principle inevitably leads to deep consequences, one of which is the two-time structure of spacetime in which ordinary 1-time spacetime is embedded. The proposed action for the Standard Model in 4+2 dimensions follows from new gauge symmetries in field theory related to the fundamental principles of Sp(2,R). These gauge symmetries thin out the degrees of freedom from 4+2 to 3+1 dimensions without any Kaluza-Klein modes.

  8. Physical models have gender‐specific effects on student understanding of protein structure–function relationships

    PubMed Central

    Harris, Michelle A.; Chang, Wesley S.; Dent, Erik W.; Nordheim, Erik V.; Franzen, Margaret A.

    2016-01-01

    Abstract Understanding how basic structural units influence function is identified as a foundational/core concept for undergraduate biological and biochemical literacy. It is essential for students to understand this concept at all size scales, but it is often more difficult for students to understand structure–function relationships at the molecular level, which they cannot as effectively visualize. Students need to develop accurate, 3‐dimensional mental models of biomolecules to understand how biomolecular structure affects cellular functions at the molecular level, yet most traditional curricular tools such as textbooks include only 2‐dimensional representations. We used a controlled, backward design approach to investigate how hand‐held physical molecular model use affected students' ability to logically predict structure–function relationships. Brief (one class period) physical model use increased quiz score for females, whereas there was no significant increase in score for males using physical models. Females also self‐reported higher learning gains in their understanding of context‐specific protein function. Gender differences in spatial visualization may explain the gender‐specific benefits of physical model use observed. © 2016 The Authors Biochemistry and Molecular Biology Education published by Wiley Periodicals, Inc. on behalf of International Union of Biochemistry and Molecular Biology, 44(4):326–335, 2016. PMID:26923186

  9. Physical models have gender-specific effects on student understanding of protein structure-function relationships.

    PubMed

    Forbes-Lorman, Robin M; Harris, Michelle A; Chang, Wesley S; Dent, Erik W; Nordheim, Erik V; Franzen, Margaret A

    2016-07-01

    Understanding how basic structural units influence function is identified as a foundational/core concept for undergraduate biological and biochemical literacy. It is essential for students to understand this concept at all size scales, but it is often more difficult for students to understand structure-function relationships at the molecular level, which they cannot as effectively visualize. Students need to develop accurate, 3-dimensional mental models of biomolecules to understand how biomolecular structure affects cellular functions at the molecular level, yet most traditional curricular tools such as textbooks include only 2-dimensional representations. We used a controlled, backward design approach to investigate how hand-held physical molecular model use affected students' ability to logically predict structure-function relationships. Brief (one class period) physical model use increased quiz score for females, whereas there was no significant increase in score for males using physical models. Females also self-reported higher learning gains in their understanding of context-specific protein function. Gender differences in spatial visualization may explain the gender-specific benefits of physical model use observed. © 2016 The Authors Biochemistry and Molecular Biology Education published by Wiley Periodicals, Inc. on behalf of International Union of Biochemistry and Molecular Biology, 44(4):326-335, 2016. PMID:26923186

  10. Physical models have gender-specific effects on student understanding of protein structure-function relationships

    PubMed Central

    Harris, Michelle A.; Chang, Wesley S.; Dent, Erik W.; Nordheim, Erik V.; Franzen, Margaret A.

    2016-01-01

    Understanding how basic structural units influence function is identified as a foundational/core concept for undergraduate biological and biochemical literacy. It is essential for students to understand this concept at all size scales, but it is often more difficult for students to understand structure-function relationships at the molecular level, which they cannot as effectively visualize. Students need to develop accurate, 3-dimensional (3D) mental models of biomolecules to understand how biomolecular structure affects cellular functions at the molecular level, yet most traditional curricular tools such as textbooks include only 2-dimensional (2D) representations. We used a controlled, backwards design approach to investigate how hand-held physical molecular model use affected students’ ability to logically predict structure-function relationships. Brief (one class period) physical model use increased quiz score for females, whereas there was no significant increase in score for males using physical models. Females also self-reported higher learning gains in their understanding of context-specific protein function. Gender differences in spatial visualization may explain the gender-specific benefits of physical model use observed. PMID:26923186

  11. Expedition Earth and Beyond: Student Scientist Guidebook. Model Research Investigation

    NASA Technical Reports Server (NTRS)

    Graff, Paige Valderrama

    2009-01-01

    The Expedition Earth and Beyond Student Scientist Guidebook is designed to help student researchers model the process of science and conduct a research investigation. The Table of Contents listed outlines the steps included in this guidebook

  12. Statistical-physical model of the hydraulic conductivity

    NASA Astrophysics Data System (ADS)

    Usowicz, B.; Marczewski, W.; Usowicz, J. B.; Lukowski, M. I.

    2012-04-01

    The water content in unsaturated subsurface soil layer is determined by processes of exchanging mass and energy between media of soil and atmosphere, and particular members of layered media. Generally they are non-homogeneous on different scales, considering soil porosity, soil texture including presence of vegetation elements in the root zone, and canopy above the surface, and varying biomass density of plants above the surface in clusters. That heterogeneity determines statistically effective values of particular physical properties. This work considers mainly those properties which determine the hydraulic conductivity of soil. This property is necessary for characterizing physically water transfer in the root zone and access of nutrient matter for plants, but it also the water capacity on the field scale. The temporal variability of forcing conditions and evolutionarily changing vegetation causes substantial effects of impact on the water capacity in large scales, bringing the evolution of water conditions in the entire area, spanning a possible temporal state in the range between floods and droughts. The dynamic of this evolution of water conditions is highly determined by vegetation but is hardly predictable in evaluations. Hydrological models require feeding with input data determining hydraulic properties of the porous soil which are proposed in this paper by means of the statistical-physical model of the water hydraulic conductivity. The statistical-physical model was determined for soils being typical in Euroregion Bug, Eastern Poland. The model is calibrated on the base of direct measurements in the field scales, and enables determining typical characteristics of water retention by the retention curves bounding the hydraulic conductivity to the state of water saturation of the soil. The values of the hydraulic conductivity in two reference states are used for calibrating the model. One is close to full saturation, and another is for low water content far

  13. Standard model of particles and forces in the framework of two-time physics

    NASA Astrophysics Data System (ADS)

    Bars, Itzhak

    2006-10-01

    In this paper it will be shown that the standard model in 3+1 dimensions is a gauge fixed version of a 2T physics field theory in 4+2 dimensions, thus establishing that 2T physics provides a correct description of nature from the point of view of 4+2 dimensions. The 2T formulation leads to phenomenological consequences of considerable significance. In particular, the higher structure in 4+2 dimensions prevents the problematic F*F term in QCD. This resolves the strong CP problem without a need for the Peccei-Quinn symmetry or the corresponding elusive axion. Mass generation with the Higgs mechanism is less straightforward in the new formulation of the standard model, but its resolution leads to an appealing deeper physical basis for mass, coupled with phenomena that could be measurable. In addition, there are some brand new mechanisms of mass generation related to the higher dimensions that deserve further study. The technical progress is based on the construction of a new field theoretic version of 2T physics including interactions in an action formalism in d+2 dimensions. The action is invariant under a new type of gauge symmetry which we call 2T-gauge symmetry in field theory. This opens the way for investigations of the standard model directly in 4+2 dimensions, or from the point of view of various embeddings of 3+1 dimensions, by using the duality, holography, symmetry, and unifying features of 2T physics.

  14. An investigation of helicopter dynamic coupling using an analytical model

    NASA Technical Reports Server (NTRS)

    Keller, Jeffrey D.

    1995-01-01

    Many attempts have been made in recent years to predict the off-axis response of a helicopter to control inputs, and most have had little success. Since physical insight is limited by the complexity of numerical simulation models, this paper examines the off-axis response problem using an analytical model, with the goal of understanding the mechanics of the coupling. A new induced velocity model is extended to include the effects of wake distortion from pitch rate. It is shown that the inclusion of these results in a significant change in the lateral flap response to a steady pitch rate. The proposed inflow model is coupled with the full rotor/body dynamics, and comparisons are made between the model and flight test data for a UH-60 in hover. Results show that inclusion of induced velocity variations due to shaft rate improves correlation in the pitch response to lateral cycle inputs.

  15. Physically Based Landslide Hazard Model U Method and Issues

    NASA Astrophysics Data System (ADS)

    Dhakal, A. S.; Sidle, R. C.

    An Integrated Dynamic Slope Stability Model (IDSSM) that integrates GIS with topo- graphic, distributed hydrologic and vegetation models to assess the slope stability at a basin scale is described to address the issues related to prediction of landslide hazards with physically based landslide models. Data limitations, which can be addressed as one of the major problem range from lack of spatially distributed data on soil depth, soil physical and engineering properties, and vegetation root strength to the need for better digital elevation models to characterize topography. Many times point data and their averages such as for soil depth and soil cohesion needs to be used as the represen- tative values at the element scale. These factors result in a great degree of uncertainty in the simulation results. Since factors related to landsliding have different degree of importance in causing landsliding the introduced uncertainties may not be identical for the entire variables. The sensitivities of different parameters associated with landslid- ing were examined using the IDSSM. Since many variables are important for landslide occurrence effects of most of the soil and vegetation parameters were evaluated. To test for parameter uncertainty, one variable is altered while others were held constant and cumulative areas (percentage of the drainage area) with safety factor less than certain values were compared. The sensitivity analysis suggests that the safety factor is most sensitive to changes in soil cohesion, soil depth, and internal frictional an- gle. Changes in hydraulic conductivity greatly influenced ground water table and thus slope stability. Parameters such as soil unit weight and tree surcharge was less sen- sitive to landsliding. Considering the possible fine spatial variation of soil depth and hydraulic conductivity in a forest soil these two factors seem to produce large uncer- tainties. In forest soil, the presence of macropores and preferential flow presents

  16. Stochastic physical ecohydrologic-based model for estimating irrigation requirement

    NASA Astrophysics Data System (ADS)

    Alizadeh, H.; Mousavi, S. J.

    2012-04-01

    Climate uncertainty affects both natural and managed hydrological systems. Therefore, methods which could take this kind of uncertainty into account are of primal importance for management of ecosystems, especially agricultural ecosystems. One of the famous problems in these ecosystems is crop water requirement estimation under climatic uncertainty. Both deterministic physically-based methods and stochastic time series modeling have been utilized in the literature. Like other fields of hydroclimatic sciences, there is a vast area in irrigation process modeling for developing approaches integrating physics of the process and statistics aspects. This study is about deriving closed-form expressions for probability density function (p.d.f.) of irrigation water requirement using a stochastic physically-based model, which considers important aspects of plant, soil, atmosphere and irrigation technique and policy in a coherent framework. An ecohydrologic stochastic model, building upon the stochastic differential equation of soil moisture dynamics at root zone, is employed as a basis for deriving the expressions considering temporal stochasticity of rainfall. Due to distinguished nature of stochastic processes of micro and traditional irrigation applications, two different methodologies have been used. Micro-irrigation application has been modeled through dichotomic process. Chapman-Kolomogrov equation of time integral of the dichotomic process for transient condition has been solved to derive analytical expressions for probability density function of seasonal irrigation requirement. For traditional irrigation, irrigation application during growing season has been modeled using a marked point process. Using the renewal theory, probability mass function of seasonal irrigation requirement, which is a discrete-value quantity, has been analytically derived. The methodology deals with estimation of statistical properties of the total water requirement in a growing season that

  17. FPGA-based distributed computing microarchitecture for complex physical dynamics investigation.

    PubMed

    Borgese, Gianluca; Pace, Calogero; Pantano, Pietro; Bilotta, Eleonora

    2013-09-01

    In this paper, we present a distributed computing system, called DCMARK, aimed at solving partial differential equations at the basis of many investigation fields, such as solid state physics, nuclear physics, and plasma physics. This distributed architecture is based on the cellular neural network paradigm, which allows us to divide the differential equation system solving into many parallel integration operations to be executed by a custom multiprocessor system. We push the number of processors to the limit of one processor for each equation. In order to test the present idea, we choose to implement DCMARK on a single FPGA, designing the single processor in order to minimize its hardware requirements and to obtain a large number of easily interconnected processors. This approach is particularly suited to study the properties of 1-, 2- and 3-D locally interconnected dynamical systems. In order to test the computing platform, we implement a 200 cells, Korteweg-de Vries (KdV) equation solver and perform a comparison between simulations conducted on a high performance PC and on our system. Since our distributed architecture takes a constant computing time to solve the equation system, independently of the number of dynamical elements (cells) of the CNN array, it allows us to reduce the elaboration time more than other similar systems in the literature. To ensure a high level of reconfigurability, we design a compact system on programmable chip managed by a softcore processor, which controls the fast data/control communication between our system and a PC Host. An intuitively graphical user interface allows us to change the calculation parameters and plot the results.

  18. FPGA-based distributed computing microarchitecture for complex physical dynamics investigation.

    PubMed

    Borgese, Gianluca; Pace, Calogero; Pantano, Pietro; Bilotta, Eleonora

    2013-09-01

    In this paper, we present a distributed computing system, called DCMARK, aimed at solving partial differential equations at the basis of many investigation fields, such as solid state physics, nuclear physics, and plasma physics. This distributed architecture is based on the cellular neural network paradigm, which allows us to divide the differential equation system solving into many parallel integration operations to be executed by a custom multiprocessor system. We push the number of processors to the limit of one processor for each equation. In order to test the present idea, we choose to implement DCMARK on a single FPGA, designing the single processor in order to minimize its hardware requirements and to obtain a large number of easily interconnected processors. This approach is particularly suited to study the properties of 1-, 2- and 3-D locally interconnected dynamical systems. In order to test the computing platform, we implement a 200 cells, Korteweg-de Vries (KdV) equation solver and perform a comparison between simulations conducted on a high performance PC and on our system. Since our distributed architecture takes a constant computing time to solve the equation system, independently of the number of dynamical elements (cells) of the CNN array, it allows us to reduce the elaboration time more than other similar systems in the literature. To ensure a high level of reconfigurability, we design a compact system on programmable chip managed by a softcore processor, which controls the fast data/control communication between our system and a PC Host. An intuitively graphical user interface allows us to change the calculation parameters and plot the results. PMID:24808576

  19. The 5th Generation model of Particle Physics

    NASA Astrophysics Data System (ADS)

    Lach, Theodore

    2009-05-01

    The Standard model of Particle Physics is able to account for all known HEP phenomenon, yet it is not able to predict the masses of the quarks or leptons nor can it explain why they have their respective values. The Checker Board Model (CBM) predicts that there are 5 generation of quarks and leptons and shows a pattern to those masses, namely each three quarks or leptons (within adjacent generations or within a generation) are related to each other by a geometric mean relationship. A 2D structure of the nucleus can be imaged as 2D plate spinning on its axis, it would for all practical circumstances appear to be a 3D object. The masses of the hypothesized ``up'' and ``dn'' quarks determined by the CBM are 237.31 MeV and 42.392 MeV respectively. These new quarks in addition to a lepton of 7.4 MeV make up one of the missing generations. The details of this new particle physics model can be found at the web site: checkerboard.dnsalias.net. The only areas were this theory conflicts with existing dogma is in the value of the mass of the Top quark. The particle found at Fermi Lab must be some sort of composite particle containing Top quarks.

  20. Physical model for characterizing and simulating a FLOTOX EEPROM device

    NASA Astrophysics Data System (ADS)

    Wu, Ching-Yuan; Chen, Chiou-Feng

    1992-05-01

    A physical model has been developed to analyze the dynamic characteristics of a FLOTOX EEPROM device. The effects of the structural parameters such as the area and thickness of the tunneling-oxide and interpoly-oxide layers are characterized by a coupling ratio to describe the discrete programming or erasing operation. The physical parameters including the electron trapping and positive-charge generation effects are used to describe the endurance and retention operations of an EEPROM device. Computer simulations based on this model have been performed to analyze the operations of an EEPROM device, including the effects of three different programming/erasing input voltage waveforms (pulse, exponential rise and triangular). A method for protecting an EEPROM device from overshooting or undershooting during programming or erasing operation is proposed. Therefore, the proposed model can be used as a computer-aided-design (CAD) tool for device design and an efficient simulation tool for describing the dynamic operation and reliability of an EEPROM device.

  1. Energy Blocks — A Physical Model for Teaching Energy Concepts

    NASA Astrophysics Data System (ADS)

    Hertting, Scott

    2016-01-01

    Most physics educators would agree that energy is a very useful, albeit abstract topic. It is therefore important to use various methods to help the student internalize the concept of energy itself and its related ideas. These methods include using representations such as energy bar graphs, energy pie charts, or energy tracking diagrams. Activities and analogies like Energy Theater and Richard Feynman's blocks, as well as the popular money (or wealth) analogy, can also be very effective. The goal of this paper is to describe a physical model of Feynman's blocks that can be employed by instructors to help students learn the following energy-related concepts: 1. The factors affecting each individual mechanical energy storage mode (this refers to what has been traditionally called a form of energy, and while the Modeling Method of instruction is not the focus of this paper, much of the energy related language used is specific to the Modeling Method). For example, how mass or height affects gravitational energy; 2. Energy conservation; and 3. The graphical relationships between the energy storage mode and a factor affecting it. For example, the graphical relationship between elastic energy and the change in length of a spring.

  2. Model problems in plasma physics and gas dynamics

    SciTech Connect

    Soto, L.A.

    1984-01-01

    The solution for the distribution function of heavy ions in a background of electrons is studied. It is found that quite broad physical conditions on the distribution function are sufficient to eliminate any ambiguity in the steady state solutions and to determine a discrete spectrum of the Fokker Planck operator for the time dependent case. The more physical case of a Maxwell Boltzman electron distribution function is treated, and under the small mass ratio expansion it is shown to lead to one of the model solutions in zero order. First order mass ratio corrections are calculated. They do not change the discrete nature of the spectrum. A plasma heating application is suggested. A hydrodynamic model is formulated to account for the collision of two compressible flows. This model is applied to the problem of the interaction of the solar wind and the interstellar medium, and for a compressible flow past a sphere as a limit case. Both flows are considered to be steady, polytropic, and potential. The compressible problem is solved by means of two different perturbation schemes (The Janzen-Rayleigh method and the coordinate expansion). For the free-stream Mach number expansion the solution up to the third order is found.

  3. Physical vulnerability modelling in natural hazard risk assessment

    NASA Astrophysics Data System (ADS)

    Douglas, J.

    2007-04-01

    An evaluation of the risk to an exposed element from a hazardous event requires a consideration of the element's vulnerability, which expresses its propensity to suffer damage. This concept allows the assessed level of hazard to be translated to an estimated level of risk and is often used to evaluate the risk from earthquakes and cyclones. However, for other natural perils, such as mass movements, coastal erosion and volcanoes, the incorporation of vulnerability within risk assessment is not well established and consequently quantitative risk estimations are not often made. This impedes the study of the relative contributions from different hazards to the overall risk at a site. Physical vulnerability is poorly modelled for many reasons: the cause of human casualties (from the event itself rather than by building damage); lack of observational data on the hazard, the elements at risk and the induced damage; the complexity of the structural damage mechanisms; the temporal and geographical scales; and the ability to modify the hazard level. Many of these causes are related to the nature of the peril therefore for some hazards, such as coastal erosion, the benefits of considering an element's physical vulnerability may be limited. However, for hazards such as volcanoes and mass movements the modelling of vulnerability should be improved by, for example, following the efforts made in earthquake risk assessment. For example, additional observational data on induced building damage and the hazardous event should be routinely collected and correlated and also numerical modelling of building behaviour during a damaging event should be attempted.

  4. The Intervention Effects of Acupuncture on Fatigue Induced by Exhaustive Physical Exercises: A Metabolomics Investigation

    PubMed Central

    Ma, Haifeng; Liu, Xia; Wu, Ying; Zhang, Naixia

    2015-01-01

    In this study, the antifatigue effects of acupuncture had been investigated at the metabolic level on the young male athletes with exhaustive physical exercises. After a series of exhaustive physical exercises and a short-term rest, the athletes either were treated with needling acupuncture on selected acupoints (TA group) or enjoyed an extended rest (TR group). NMR-based metabolomics analysis was then applied to depict the metabolic profiles of urine samples, which were collected from the athletes at three time points including the time before exercises, the time before and after the treatment of acupuncture, or taking the extended rest. The results from multivariate statistical analysis indicated that the recoveries of disturbed metabolites in the athletes treated with acupuncture were significantly faster than in those only taking rest. After the treatment with acupuncture, the levels of distinguished metabolites, 2-hydroxybutyrate, 3-hydroxyisovalerate, lactate, pyruvate, citrate, dimethylglycine, choline, glycine, hippurate, and hypoxanthine were recovered at an accelerated speed in the TA group in comparison with the TR group. The above-mentioned results indicated that the acupuncture treatment ameliorated fatigue by backregulating the perturbed energy metabolism, choline metabolism, and attenuating the ROS-induced stress at an accelerated speed, which demonstrated that acupuncture could serve as an alternative fatigue-relieving approach. PMID:26442121

  5. The investigation of physical conditions of boron uptake region in proton boron fusion therapy (PBFT)

    NASA Astrophysics Data System (ADS)

    Jung, Joo-Young; Yoon, Do-Kun; Lee, Heui Chang; Lu, Bo; Suh, Tae Suk

    2016-09-01

    We conducted a quantitative study to identify the effectiveness of proton boron fusion therapy (PBFT). Four simulation scenarios were designed to investigate the escalation in total dose with the proton boron reaction using a Monte Carlo n-particle extended (MCNPX 2.6.0) simulation. The peak integrated dose was obtained for three different physical conditions (i.e., boron uptake region (BUR) thickness, BUR location, and boron concentration) with differing proton beam energy (60-90 MeV). We found that the peak integrated dose was increased by up to 96.62% compared to the pristine proton Bragg-peak. For the synergetic effect to take place with 60-70 MeV proton beam, the BUR had to be at least 0.3 cm thick while spanning the Bragg-peak. Similarly to the thickness, the BUR location needed to be within 0.3 cm from the Bragg-peak when the thickness was maintained at 0.9 cm. An effective proton boron reaction required the boron concentration to be equal to or greater than 14.4 mg/g. These results demonstrate the impact of various physical and beam conditions of the PBFT, which are critical environmental factors for the treatment planning. We envision that this study will advance our understanding of the PBFT, which can be an invaluable treatment method for maximizing the potential of proton therapy.

  6. Social inequality: from data to statistical physics modeling

    NASA Astrophysics Data System (ADS)

    Chatterjee, Arnab; Ghosh, Asim; Inoue, Jun-ichi; Chakrabarti, Bikas K.

    2015-09-01

    Social inequality is a topic of interest since ages, and has attracted researchers across disciplines to ponder over it origin, manifestation, characteristics, consequences, and finally, the question of how to cope with it. It is manifested across different strata of human existence, and is quantified in several ways. In this review we discuss the origins of social inequality, the historical and commonly used non-entropic measures such as Lorenz curve, Gini index and the recently introduced k index. We also discuss some analytical tools that aid in understanding and characterizing them. Finally, we argue how statistical physics modeling helps in reproducing the results and interpreting them.

  7. Non-perturbative QCD Modeling and Meson Physics

    SciTech Connect

    Nguyen, T.; Souchlas, N. A.; Tandy, P. C.

    2009-04-20

    Using a ladder-rainbow kernel previously established for light quark hadron physics, we explore the extension to masses and electroweak decay constants of ground state pseudoscalar and vector quarkonia and heavy-light mesons in the c- and b-quark regions. We make a systematic study of the effectiveness of a constituent mass concept as a replacement for a heavy quark dressed propagator for such states. The difference between vector and axial vector current correlators is explored within the same model to provide an estimate of the four quark chiral condensate and the leading distance scale for the onset of non-perturbative phenomena in QCD.

  8. An Aerosol Physical Chemistry Model for the Upper Troposphere

    NASA Technical Reports Server (NTRS)

    Lin, Jin-Sheng

    2001-01-01

    This report is the final report for the Cooperative Agreement NCC2-1000. The tasks outlined in the various proposals are listed with a brief comment as to the research performed. The publications titles are: The effects of particle size and nitric acid uptake on the homogenous freezing of sulfate aerosols; Parameterization of an aerosol physical chemistry model (APCM) for the NH3/H2SO4/HNO3/H2O system at cold temperatures; and The onset, extent and duration of dehydration in the Southern Hemisphere polar vortex.

  9. Non-perturbative QCD Modeling and Meson Physics

    NASA Astrophysics Data System (ADS)

    Nguyen, T.; Souchlas, N. A.; Tandy, P. C.

    2009-04-01

    Using a ladder-rainbow kernel previously established for light quark hadron physics, we explore the extension to masses and electroweak decay constants of ground state pseudoscalar and vector quarkonia and heavy-light mesons in the c- and b-quark regions. We make a systematic study of the effectiveness of a constituent mass concept as a replacement for a heavy quark dressed propagator for such states. The difference between vector and axial vector current correlators is explored within the same model to provide an estimate of the four quark chiral condensate and the leading distance scale for the onset of non-perturbative phenomena in QCD.

  10. Investigation of Hybrid States in the VES Experiment at the Institute for High Energy Physics (Protvino)

    SciTech Connect

    Amelin, D.V.; Gavrilov, Yu.G.; Gouz, Yu.P.; Dorofeev, V.A.; Dzhelyadin, R.I.; Zaitsev, A.M.; Zenin, A.V.; Ivashin, A.V.; Kachaev, I.A.; Kabachenko, V.V.; Karyukhin, A.N.; Konoplyannikov, A.N.; Konstantinov, V.F.; Kostyukhin, V.V.; Matveev, V.D.; Nikolaenko, V.I.; Ostankov, A.P.; Polyakov, B.F.; Ryabchikov, D.I.; Solodkov, A.A.

    2005-03-01

    Experimental investigations of candidates for hybrid mesons in the VES experiment at the Institute for High Energy Physics (Protvino) are surveyed. The data in question concern {pi}{sub 1}(1400) characterized by the exotic quantum numbers of J{sup PC} = 1{sup -+} and observed in the {eta}{pi}{sup -} final state; J{sup PC} 1{sup -+} {pi}{sub 1}(1600) in the {eta}{sup '}{pi}{sup -}, b{sub 1}(1235){pi}, and f{sub 1}(1285){pi}{sup -} final states; and J{sup PC} = 0{sup -+} {pi}(1800) in the f{sub 0}(980){pi}{sup -}, f{sub 0}(1300){pi}{sup -}, f{sub 0}(1500){pi}{sup -}, and a{sub 0}{sup -}(980){eta} final states. New results are given along with data published previously.

  11. Investigation of physical and biological properties of polypyrrole nanotubes-chitosan nanocomposites.

    PubMed

    Upadhyay, J; Kumar, A; Gupta, K; Mandal, M

    2015-11-01

    Polypyrrole nanotubes-chitosan (PPy-NTs:chitosan) nanocomposite films have been synthesized with varying concentration of polypyrrole nanotubes (PPy-NTs) and their physical and biological properties have been investigated. Scanning electron microscopy (SEM) micrographs exhibit the increase in surface roughness of the nanocomposite films with increasing concentration of PPy-NTs. Enhancement in hydrophilicity of the nanocomposite films has been observed after surface functionalization with glutaraldehyde which is attributed to increase in surface energy due to the incorporation of polar groups on the films surface. The increasing amount of PPy-NTs in the nanocomposite leads to an increase in haemolysis activity, while the treatment with glutaraldehyde results in the decrease in haemolysis activity giving rise to higher biocompatibility. Urease immobilization in glutaraldehyde treated films exhibits higher enzymatic activity as compared to that of the untreated films, which is attributed to the enhancement in hydrophilicity and biocompatibility of the PPy-NTs:chitosan nanocomposites after functionalization with glutaraldehyde. PMID:26256373

  12. Investigating the LGBTQ Responsive Model for Supervision of Group Work

    ERIC Educational Resources Information Center

    Luke, Melissa; Goodrich, Kristopher M.

    2013-01-01

    This article reports an investigation of the LGBTQ Responsive Model for Supervision of Group Work, a trans-theoretical supervisory framework to address the needs of lesbian, gay, bisexual, transgender, and questioning (LGBTQ) persons (Goodrich & Luke, 2011). Findings partially supported applicability of the LGBTQ Responsive Model for Supervision…

  13. An investigation of simple nonsmooth power system models

    SciTech Connect

    Mantri, R.; Venkatasubramanian, V.; Saberi, A.

    1994-12-31

    Recently new notions of solutions and equilibrium points have been proposed for analyzing nonsmooth system descriptions. This paper observes certain new phenomena in simple nonsmooth power system models presenting a preliminary analysis. The results include an investigation of new Hopf-like bifurcations related to the birth of limit cycles in two dimensional non-Lipschitzian power system models.

  14. The Ising model in physics and statistical genetics.

    PubMed

    Majewski, J; Li, H; Ott, J

    2001-10-01

    Interdisciplinary communication is becoming a crucial component of the present scientific environment. Theoretical models developed in diverse disciplines often may be successfully employed in solving seemingly unrelated problems that can be reduced to similar mathematical formulation. The Ising model has been proposed in statistical physics as a simplified model for analysis of magnetic interactions and structures of ferromagnetic substances. Here, we present an application of the one-dimensional, linear Ising model to affected-sib-pair (ASP) analysis in genetics. By analyzing simulated genetics data, we show that the simplified Ising model with only nearest-neighbor interactions between genetic markers has statistical properties comparable to much more complex algorithms from genetics analysis, such as those implemented in the Allegro and Mapmaker-Sibs programs. We also adapt the model to include epistatic interactions and to demonstrate its usefulness in detecting modifier loci with weak individual genetic contributions. A reanalysis of data on type 1 diabetes detects several susceptibility loci not previously found by other methods of analysis.

  15. Physics-based Entry, Descent and Landing Risk Model

    NASA Technical Reports Server (NTRS)

    Gee, Ken; Huynh, Loc C.; Manning, Ted

    2014-01-01

    A physics-based risk model was developed to assess the risk associated with thermal protection system failures during the entry, descent and landing phase of a manned spacecraft mission. In the model, entry trajectories were computed using a three-degree-of-freedom trajectory tool, the aerothermodynamic heating environment was computed using an engineering-level computational tool and the thermal response of the TPS material was modeled using a one-dimensional thermal response tool. The model was capable of modeling the effect of micrometeoroid and orbital debris impact damage on the TPS thermal response. A Monte Carlo analysis was used to determine the effects of uncertainties in the vehicle state at Entry Interface, aerothermodynamic heating and material properties on the performance of the TPS design. The failure criterion was set as a temperature limit at the bondline between the TPS and the underlying structure. Both direct computation and response surface approaches were used to compute the risk. The model was applied to a generic manned space capsule design. The effect of material property uncertainty and MMOD damage on risk of failure were analyzed. A comparison of the direct computation and response surface approach was undertaken.

  16. A Goddard Multi-Scale Modeling System with Unified Physics

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo

    2010-01-01

    A multi-scale modeling system with unified physics has been developed at NASA Goddard Space Flight Center (GSFC). The system consists of an MMF, the coupled NASA Goddard finite-volume GCM (fvGCM) and Goddard Cumulus Ensemble model (GCE, a CRM); the state-of-the-art Weather Research and Forecasting model (WRF) and the stand alone GCE. These models can share the same microphysical schemes, radiation (including explicitly calculated cloud optical properties), and surface models that have been developed, improved and tested for different environments. In this talk, I will present: (1) A brief review on GCE model and its applications on the impact of the aerosol on deep precipitation processes, (2) The Goddard MMF and the major difference between two existing MMFs (CSU MMF and Goddard MMF), and preliminary results (the comparison with traditional GCMs), and (3) A discussion on the Goddard WRF version (its developments and applications). We are also performing the inline tracer calculation to comprehend the ph ysical processes (i.e., boundary layer and each quadrant in the boundary layer) related to the development and structure of hurricanes and mesoscale convective systems.

  17. Increasing physical activity levels in primary school physical education: The SHARP Principles Model

    PubMed Central

    Powell, Emma; Woodfield, Lorayne A.; Nevill, Alan M.

    2015-01-01

    Objectives: To evaluate the effectiveness of a one-year teaching intervention to increase moderate to vigorous physical activity (MVPA) during primary school physical education (PE). Methods: A quasi-experimental, non-equivalent group design involving four classes from two primary schools in the West Midlands, UK. In March 2014 schools were selected through purposive sampling to match schools in terms of size and demographics (baseline, n = 111: post-intervention, n = 95); data were collected from children in school years 3 and 4 (aged 7 to 9 years). The intervention involved developing teacher effectiveness through the SHARP Principles Model which was grounded in the Self Determination Theory (SDT), the Social Ecological Model (SEM) and three key ingredients from the Behaviour Change Taxonomy (BCT). MVPA was assessed at baseline and four weeks post-intervention using the System for Observing Fitness and Instruction Time (SOFIT). Four individual teacher interviews were conducted with the intervention school, to explore teachers' perceptions of the intervention. Results: A two-way ANOVA (Analysis of Variance) indicated large interaction effect sizes for time spent in MVPA (F(1, 27) = 11.07, p = 0.003, ηp2 = .316) and vigorous activity (VPA) (F = (1,27) = 8.557, p = .007, ηp2 = .263). PA in the intervention school increased significantly whereas in the control school MVPA remained relatively constant and VPA decreased. The qualitative findings revealed two main emergent themes: a paradigm shift and teacher's developing pedagogy. Conclusions: The intervention was effective in increasing MVPA in PE. Recommendations based on this evaluation would be for the SHARP Principles Model to be replicated and evaluated on a wider scale across a variety of contexts. PMID:26844179

  18. Noise in the brain: a physical network model.

    PubMed

    Haken, H

    1996-09-01

    In the brain as in any other open physical systems, noise is inevitable. We present an explicit model of an active physical system that is borrowed from laser physics and allows us to establish the properties of the fluctuating forces that cause noise in the system. It is shown how the cooperation of the individual parts of a system (atoms or neurons) can considerably reduce the noise level. In particular we determine the correlation function between the individual parts. The basic equations can be transformed in such a way that a close analogy with typical equations of neural nets are obtained. In particular, the nonlinear properties of neurons described by the sigmoid function are well captured. Propagation of excitation in axons and dendrites is represented by a linear equation, where we consider both a bandwidth filter and more or less free propagation. In the latter case, a close analogy with an equation for neural activity in the sense of Nunez and established by Jirsa and Haken is pointed out.

  19. Impact Flash Physics: Modeling and Comparisons With Experimental Results

    NASA Astrophysics Data System (ADS)

    Rainey, E.; Stickle, A. M.; Ernst, C. M.; Schultz, P. H.; Mehta, N. L.; Brown, R. C.; Swaminathan, P. K.; Michaelis, C. H.; Erlandson, R. E.

    2015-12-01

    Hypervelocity impacts frequently generate an observable "flash" of light with two components: a short-duration spike due to emissions from vaporized material, and a long-duration peak due to thermal emissions from expanding hot debris. The intensity and duration of these peaks depend on the impact velocity, angle, and the target and projectile mass and composition. Thus remote sensing measurements of planetary impact flashes have the potential to constrain the properties of impacting meteors and improve our understanding of impact flux and cratering processes. Interpreting impact flash measurements requires a thorough understanding of how flash characteristics correlate with impact conditions. Because planetary-scale impacts cannot be replicated in the laboratory, numerical simulations are needed to provide this insight for the solar system. Computational hydrocodes can produce detailed simulations of the impact process, but they lack the radiation physics required to model the optical flash. The Johns Hopkins University Applied Physics Laboratory (APL) developed a model to calculate the optical signature from the hot debris cloud produced by an impact. While the phenomenology of the optical signature is understood, the details required to accurately model it are complicated by uncertainties in material and optical properties and the simplifications required to numerically model radiation from large-scale impacts. Comparisons with laboratory impact experiments allow us to validate our approach and to draw insight regarding processes that occur at all scales in impact events, such as melt generation. We used Sandia National Lab's CTH shock physics hydrocode along with the optical signature model developed at APL to compare with a series of laboratory experiments conducted at the NASA Ames Vertical Gun Range. The experiments used Pyrex projectiles to impact pumice powder targets with velocities ranging from 1 to 6 km/s at angles of 30 and 90 degrees with respect to

  20. Comparison between empirical and physically based models of atmospheric correction

    NASA Astrophysics Data System (ADS)

    Mandanici, E.; Franci, F.; Bitelli, G.; Agapiou, A.; Alexakis, D.; Hadjimitsis, D. G.

    2015-06-01

    A number of methods have been proposed for the atmospheric correction of the multispectral satellite images, based on either atmosphere modelling or images themselves. Full radiative transfer models require a lot of ancillary information about the atmospheric conditions at the acquisition time. Whereas, image based methods cannot account for all the involved phenomena. Therefore, the aim of this paper is the comparison of different atmospheric correction methods for multispectral satellite images. The experimentation was carried out on a study area located in the catchment area of Yialias river, 20 km South of Nicosia, the Cyprus capital. The following models were tested, both empirical and physically based: Dark object subtraction, QUAC, Empirical line, 6SV, and FLAASH. They were applied on a Landsat 8 multispectral image. The spectral signatures of ten different land cover types were measured during a field campaign in 2013 and 15 samples were collected for laboratory measurements in a second campaign in 2014. GER 1500 spectroradiometer was used; this instrument can record electromagnetic radiation from 350 up to 1050 nm, includes 512 different channels and each channel covers about 1.5 nm. The spectral signatures measured were used to simulate the reflectance values for the multispectral sensor bands by applying relative spectral response filters. These data were considered as ground truth to assess the accuracy of the different image correction models. Results do not allow to establish which method is the most accurate. The physics-based methods describe better the shape of the signatures, whereas the image-based models perform better regarding the overall albedo.