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Sample records for airshed model uam

  1. User's guide for the Urban Airshed Model. Volume 5. Description and operation of the ROM - UAM interface program system

    SciTech Connect

    Tang, R.T.; Gerry, S.C.; Newsome, J.S.; Van Meter, A.R.; Wayland, R.A.

    1990-06-01

    The user's guide for the Urban Airshed Model (UAM) is divided into five volumes. Volume V describes the ROM-UAM interface program system, a software package that can be used to generate UAM input files from inputs and outputs provided by the EPA Regional Oxidant Model (ROM).

  2. Sensitivity of Urban Airshed Model (UAM-IV) calculated air pollutant concentrations to the vertical diffusion parameterization during convective meteorological situations

    SciTech Connect

    Nowacki, P.; Samson, P.J.; Sillman, S.

    1996-10-01

    It is shown that Urban Airshed Model (UAM-IV) calculated air pollutant concentrations during photochemical smog episodes in Atlanta, Georgia, depend strongly on the numerical parameterization of the daytime vertical diffusivity. Results found suggest that vertical mixing is overestimated by the UAM-IV during unstable daytime conditions, as calculated vertical diffusivity values exceed measured and comparable literature values. Although deviations between measured and UAM-IV calculated air pollutant concentrations may only in part be due the UAM-IV diffusivity parameterization, results indicate the large error potential in vertical diffusivity parameterization. Easily implemented enhancements to UAM-IV algorithms are proposed, thus improving UAM-IV modeling performance during unstable stratification. 38 refs., 14 figs., 1 tab.

  3. A field study for the validation and implementation of the urban airshed model (UAM) in the complex terrain surrounding Salt Lake City, Utah

    SciTech Connect

    Swart, H.R.; Barickman, P.R.; Wilkerson, G.W.; Hauze, W.

    1998-12-31

    Historically the Wasatch Front has exceeded the existing one-hour ozone standard, and is expected to have difficulty meeting the new 8-hour standard. To better understand and forecast these exceedance episodes the Utah Division of Air Quality (UDAQ) has elected to apply the Urban Airshed Model (UAM). The application of UAM in this area is difficult because of the Wasatch mountain range to the east of the urbanized area and the Great Salt Lake to the west. The UDAQ sponsored a field data measurement project during the summer of 1996 to support the UAM effort. Special intensive measurements of meteorology, precursor emissions, and chemistry, at ground level and aloft, were conducted on five days to develop a more complete understanding of ozone and its evolutionary process. Aircraft and ground-based mobile measurements of air quality and meteorology supplemented the existing networks to define the boundary conditions as well as document the chemical changes and transport within the airshed. On the study days ozone concentrations did not exceed the 1-hour standard but did exceed the 8-hour standard. The field effort has provided valuable data for characterizing the complex meteorology and boundary conditions in the airshed. This paper discusses the data analysis as it applies to the development of wind fields with the Diagnostic Wind Model (DWM)1 for use in the UAM.

  4. Sensitivity of the urban airshed model to mixing height profiles

    SciTech Connect

    Rao, S.T.; Sistla, G.; Ku, J.Y.; Zhou, N.; Hao, W.

    1994-12-31

    The United States Environmental Protection Agency (USEPA) has recommended the use of the Urban Airshed Model (UAM), a grid-based photochemical model, for regulatory applications. One of the important parameters in applications of the UAM is the height of the mixed layer or the diffusion break. In this study, we examine the sensitivity of the UAM-predicted ozone concentrations to (a) a spatially invariant diurnal mixing height profile, and (b) a spatially varying diurnal mixing height profile for a high ozone episode of July 1988 for the New York Airshed. The 1985/88 emissions inventory used in the EPA`s Regional Oxidant Modeling simulations has been regridded for this study. Preliminary results suggest that the spatially varying case yields a higher peak ozone concentrations compared to the spatially invariant mixing height simulation, with differences in the peak ozone ranging from a few ppb to about 40 ppb for the days simulated. These differences are attributed to the differences in the shape of the mixing height profiles and its rate of growth during the morning hours when peak emissions are injected into the atmosphere. Examination of the impact of emissions reductions associated with these two mixing height profiles indicates that NO{sub x}-focussed controls provide a greater change in the predicted ozone peak under spatially invariant mixing heights than under the spatially varying mixing height profile. On the other hand, VOC-focussed controls provide a greater change in the predicted peak ozone levels under spatially varying mixing heights than under the spatially invariant mixing height profile.

  5. Photochemical urban airshed modeling using diagnostic and dynamic meteorological fields

    NASA Astrophysics Data System (ADS)

    Godowitch, J. M.; Vukovich, J. M.

    1994-06-01

    Spatial pollutant patterns and peak concentrations are strongly influenced by meteorological parameters. Therefore, accurate hourly, gridded meteorological data sets are crucial inputs for photochemical modeling. An effort has been underway to apply both diagnostic and dynamic meteorological models in order to generate inputs needed in photochemical grid model simulations. The model being employed is a modified version of the Urban Airshed Model (UAM), which was designed to accept input files generated from both meteorological approaches. The diagnostic meteorological model (UAMMET) relies on routine or intensive measurements to generate hourly 3-D gridded fields of winds, temperatures, vertical eddy diffusivities, photolytic rates, and hourly spatially-varying fields of mixing height and deposition velocities. The diagnostic wind model (DWM) is a key module used generate 3-D wind fields. A dynamic mesoscale meteorological model (a numerical hydrostatic code equipped with a four-dimensional data assimilation technique) generates a gridded meteorological output file, which is post-processed through an interface program to create UAM-compatible wind and mixing height files. In this effort, both meteorological models were exercised in two different urban domains situated next to water bodies and with significant terrain features (i.e., greater metropolitan NYC and LA basin). Results of simulations with the modified UAM model were evaluated in order to investigate the impact on modeled ozone patterns and peak concentrations using inputs from these two meteorological approaches. A historical high ozone day in the NYC domain was simulated which exhibited a strong large scale flow pattern conducive to interurban transport along the northeastern coast. The evaluation results revealed absolute errors were comparable (about 22%) among the simulations, however, higher peak ozone was obtained using dynamically generated wind fields. Results from simulations of an ozone episode

  6. The suitability of low-cost urban airshed modeling in the Chicago area

    SciTech Connect

    Fernau, M.E.; Makofske, W.J.; South, D.W.

    1994-01-01

    The interesting composition of the utility mix in the Chicago region and the potential for electric vehicle use in that area make it an interesting candidate for emissions sensitivity and scenario studies. However, it is difficult to apply the Urban Airshed Model (UAM) to the Chicago region because of the complex meteorology associated with Lake Michigan. The Lake Michigan Air Directors consortium (LADCO) has developed, at considerable expense, an improved version with nested grids and embedded plumes (UAM-V) for application in the Lake Michigan Ozone Study (LMOS) and for regulatory use. The complexity of the LMOS modeling system makes it costly and time-consuming to implement. In this study, the authors apply UAM-IV (US Environmental Protection, 1990a) in its simple ``PLANR (Practice for Low-cost Application in Nonattainment Regions)`` mode (US Environmental Protect Agency, 1990b) to the Chicago region to study various interesting scenarios in a rapid and low-cost manner. The details of the data sets, methods and results of this study are contained in Fernau et al. and are summarized here. In addition, the authors comment on the usefulness of this type of limited-data study as compared to more complex modeling systems and data inputs.

  7. Study using a three-dimensional photochemical smog formation model under conditions of complex flow: Application of the Urban Airshed Model to the Tokyo Metropolitan Area. Rept. for Jan 85-Jan 91

    SciTech Connect

    Wakamatsu, S.; Schere, K.L.

    1991-03-01

    The purpose of the study is to evaluate the Urban Airshed Model (UAM), a three-dimensional photochemical urban air quality simulation model, using field observations from the Tokyo Metropolitan Area. Emphasis was placed on the photochemical smog formation mechanism under stagnant meteorological conditions. The UAM produced reasonable calculated results for the diurnal, areal and vertical distributions of O3 concentrations covering the Tokyo Metropolitan Area. The role and significance of the previous day's secondary pollutants on O3 formation mechanisms were also investigated. During the night time, high values of secondary pollutant concentrations were predicted above the radiation inversion layer. These aged pollutants were then entrained into the mixing layer during the day in accordance with the elevation of the lid. These characteristic features were also observed in the field study.

  8. Sensitivity of the UAM-predicted ozone concentrations to wind fields in the New York metropolitan area

    SciTech Connect

    Sistla, G.; Ku, J.Y.; Zhou, N.; Hao, W.; Rao, S.T.; Thunis, P.; Bornstein, R.; Freedman, F.

    1994-12-31

    The New York airshed modeling domain, extending from northern Philadelphia, PA to the southern Massachusetts, is part of the large urban corridor stretching from Virginia to Maine alone the eastern sea-board of United States. Due to the continued non-attainment of the National Ambient Air Quality Standard (NAAQS) for ozone, the area has been designated to be in the {open_quotes}severe{close_quotes} classification under the 1990 Clean Air Act Amendments. This requires demonstration of compliance with the ozone NAAQS with grid-based photochemical models such as the Urban Airshed Model (UAM). The United States Environmental Protection Agency (USEPA) has recommended the use of a one-way model nesting scheme, with the Regional Oxidant Model (ROM) providing initial and boundary conditions and other ancillary data for the UAM. Meteorological data and emissions data can also be developed by alternative methods for use with UAM, if considered more appropriate than those derived from the ROM-UAM system.

  9. SAI (Systems Applications, Incorporated) airshed model operations manuals. Volume 2: Systems manual

    NASA Astrophysics Data System (ADS)

    Ames, J.; Hayes, S. R.; Myers, T. C.; Whitney, D. C.

    1985-04-01

    The SAI Airshed Model System is described fro a programmer's point of view. Included are discussions of all subroutines and how they fit together, run-time core allocation techniques, internal methods of segment handling using secondary storage, and detailed definitions of the structure of each file in the ystem. This manual also includes suggestions for implementing the programs on different computers. The SAI Airshed Model System consists of 17 programs that communicate with each other through 17; data files; both the programs and files are described in detail in this manual. An overview briefly describing the programs used to perform each of the five system functions is presented. Guidelines for implementing the programs, detailed descriptions of the programs by function, including hierarchical subroutine tables and short module descriptions, and detailed file structure definitions for each file in the system are given.

  10. Development of a comprehensive air quality modeling framework for a coastal urban airshed in south Texas

    NASA Astrophysics Data System (ADS)

    Farooqui, Mohmmed Zuber

    Tropospheric ozone is one of the major air pollution problems affecting urban areas of United States as well as other countries in the world. Analysis of surface observed ozone levels in south and central Texas revealed several days exceeding 8-hour average ozone National Ambient of Air Quality Standards (NAAQS) over the past decade. Two major high ozone episodes were identified during September of 1999 and 2002. A photochemical modeling framework for the high ozone episodes in 1999 and 2002 were developed for the Corpus Christi urban airshed. The photochemical model was evaluated as per U.S. Environmental Protection Agency (EPA) recommended statistical methods and the models performed within the limits set by EPA. An emission impact assessment of various sources within the urban airshed was conducted using the modeling framework. It was noted that by nudging MM5 with surface observed meteorological parameters and sea-surface temperature, the coastal meteorological predictions improved. Consequently, refined meteorology helped the photochemical model to better predict peak ozone levels in urban airsheds along the coastal margins of Texas including in Corpus Christi. The emissions assessment analysis revealed that Austin and San Antonio areas were significantly affected by on-road mobile emissions from light-duty gasoline and heavy-duty diesel vehicles. The urban areas of San Antonio, Austin, and Victoria areas were estimated to be NOx sensitive. Victoria was heavily influenced by point sources in the region while Corpus Christi was influenced by both point and non-road mobile sources and was identified to be sensitive to VOC emissions. A rise in atmospheric temperature due to climate change potentially increase ozone exceedances and the peak ozone levels within the study region and this will be a major concern for air quality planners. This study noted that any future increase in ambient temperature would result in a significant increase in the urban and regional

  11. Using the regional acid deposition model to determine the nitrogen deposition airshed of the Chesapeake Bay watershed. Book chapter

    SciTech Connect

    Dennis, R.L.

    1995-08-25

    The Regional Acid Deposition Model, RADM, an advanced Eulerian model, is used to develop an estimate of the primary airshed of nitrogen oxide (NOx) emissions that is contributing nitrogen deposition to the Chesapeake Bay watershed. A brief description of RADM together with a summary of the aggregation method used to develop annual average deposition is given. The evaluation background of RADM is summarized. The transport range of the nitrogen affecting deposition, principally the termination product nitric acid, is first established in the model. This range is compared to that determined for sulfur.

  12. Urban airshed modeling of air quality impacts of alternative transportation fuel use in Los Angeles and Atlanta

    SciTech Connect

    1997-12-01

    The main objective of NREL in supporting this study is to determine the relative air quality impact of the use of compressed natural gas (CNG) as an alternative transportation fuel when compared to low Reid vapor pressure (RVP) gasoline and reformulated gasoline (RFG). A table lists the criteria, air toxic, and greenhouse gas pollutants for which emissions were estimated for the alternative fuel scenarios. Air quality impacts were then estimated by performing photochemical modeling of the alternative fuel scenarios using the Urban Airshed Model Version 6.21 and the Carbon Bond Mechanism Version IV (CBM-IV) (Geary et al., 1988) Using this model, the authors examined the formation and transport of ozone under alternative fuel strategies for motor vehicle transportation sources for the year 2007. Photochemical modeling was performed for modeling domains in Los Angeles, California, and Atlanta, Georgia.

  13. Evaluating spatial outliers and integrating temporal data in air pollution models for the Detroit-Windsor airshed

    NASA Astrophysics Data System (ADS)

    O'Leary, Brendan F.

    The heterogeneous nature of urban air complicates human exposure estimates and creates a need for accurate, highly detailed spatiotemporal air contaminant models. The study expands on previous investigations by the Geospatial Determinants of Health Outcomes Consortium that examined relationships between air pollutant distributions and asthma exacerbations. Two approaches, the removal of spatial data outliers and the integration of spatial and temporal data, were used to refine air quality models in the Detroit and Windsor international airshed. The evaluation of associations between the resulting air quality models and asthma exacerbations in Detroit and Windsor revealed weaker correlations with spatial outliers removed but improved correlations with the addition of temporal data. Recommendations for future work include increasing the spatial and temporal resolution of the asthma datasets and incorporating Windsor NAPS data through temporal scaling to help confirm the findings of the Detroit temporal scaling.

  14. SPATIAL ANALYSIS OF AIR POLLUTION AND DEVELOPMENT OF A LAND-USE REGRESSION ( LUR ) MODEL IN AN URBAN AIRSHED

    EPA Science Inventory

    The Detroit Children's Health Study is an epidemiologic study examining associations between chronic ambient environmental exposures to gaseous air pollutants and respiratory health outcomes among elementary school-age children in an urban airshed. The exposure component of this...

  15. Modeling the effects of VOC/NOx emissions on ozone synthesis in the cascadia airshed of the Pacific Northwest.

    PubMed

    Barna, M; Lamb, B; Westberg, H

    2001-07-01

    A modeling system consisting of MM5, Calmet, and Calgrid was used to investigate the sensitivity of anthropogenic volatile organic compound (VOC) and oxides of nitrogen (NOx) reductions on ozone formation within the Cascadia airshed of the Pacific Northwest. An ozone episode that occurred on July 11-14, 1996, was evaluated. During this event, high ozone levels were recorded at monitors downwind of Seattle, WA, and Portland, OR, with one monitor exceeding the 1 hr/120 ppb National Ambient Air Quality Standard (at 148 ppb), and six monitors above the proposed 8 hr/80 ppb standard (at 82-130 ppb). For this particular case, significant emissions reductions, between 25 and 75%, would be required to decrease peak ozone concentrations to desired levels. Reductions in VOC emissions alone, or a combination of reduced VOC and NOx emissions, were generally found to be most effective; reducing NOx emissions alone resulted in increased ozone in the Seattle area. When only VOC emissions were curtailed, ozone reductions occurred in the immediate vicinity of densely populated areas, while NOx reductions resulted in more widespread ozone reductions. PMID:15658221

  16. Development of Land Use Regression models for particulate matter and associated components in a low air pollutant concentration airshed

    NASA Astrophysics Data System (ADS)

    Dirgawati, Mila; Heyworth, Jane S.; Wheeler, Amanda J.; McCaul, Kieran A.; Blake, David; Boeyen, Jonathon; Cope, Martin; Yeap, Bu Beng; Nieuwenhuijsen, Mark; Brunekreef, Bert; Hinwood, Andrea

    2016-11-01

    Perth, Western Australia represents an area where pollutant concentrations are considered low compared with international locations. Land Use Regression (LUR) models for PM10, PM2.5 and PM2.5 Absorbance (PM2.5Abs) along with their elemental components: Fe, K, Mn, V, S, Zn and Si were developed for the Perth Metropolitan area in order to estimate air pollutant concentrations across Perth. The most important predictor for PM10 was green spaces. Heavy vehicle traffic load was found to be the strongest predictor for PM2.5Abs. Traffic variables were observed to be the important contributors for PM10 and PM2.5 elements in Perth, except for PM2.5 V which had distance to coast as the predominant predictor. Open green spaces explained more of the variability in the PM10 elements than for PM2.5 elements, and population density was more important for PM2.5 elements than for PM10 elements. The PM2.5 and PM2.5Abs LUR models explained 67% and 82% of the variance, respectively, but the PM10 model only explained 35% of the variance. The PM2.5 models for Mn, V, and Zn explained between 70% and 90% of the variability in concentrations. PM10 V, Si, K, S and Fe models explained between 53% and 71% of the variability in respective concentrations. Testing the models using leave one-out cross validation, hold out validation and cross-hold out validation supported the validity of LUR models for PM10, PM2.5 and PM2.5Abs and their corresponding elements in Metropolitan Perth despite the relatively low concentrations.

  17. Air quality modeling of selected aromatic and non-aromatic air toxics in the Houston urban and industrial airshed

    NASA Astrophysics Data System (ADS)

    Coarfa, Violeta Florentina

    2007-12-01

    Air toxics, also called hazardous air pollutants (HAPs), pose a serious threat to human health and the environment. Their study is important in the Houston area, where point sources, mostly located along the Ship Channel, mobile and area sources contribute to large emissions of such toxic pollutants. Previous studies carried out in this area found dangerous levels of different HAPs in the atmosphere. This thesis presents several studies that were performed for the aromatic and non-aromatic air toxics in the HGA. For these studies we developed several tools: (1) a refined chemical mechanism, which explicitly represents 18 aromatic air toxics that were lumped under two model species by the previous version, based on their reactivity with the hydroxyl radical; (2) an engineering version of an existing air toxics photochemical model that enables us to perform much faster long-term simulations compared to the original model, that leads to a 8--9 times improvement in the running time across different computing platforms; (3) a combined emission inventory based on the available emission databases. Using the developed tools, we quantified the mobile source impact on a few selected air toxics, and analyzed the temporal and spatial variation of selected aromatic and non-aromatic air toxics in a few regions within the Houston area; these regions were characterized by different emissions and environmental conditions.

  18. Comparison of ionospheric parameters calculated with UAM and measured at Voeykovo observatory

    NASA Astrophysics Data System (ADS)

    Rybakov, M. V.; Namgaladze, A. A.; Karpov, M. I.

    2016-09-01

    The measurements of the critical frequencies of the ionospheric F2 layer based on vertical radiosounding, which was performed with a CADI digital ionosonde at the Voeykovo magnetic-ionospheric observatory in February 2013, have been considered. The observations have been compared with the upper atmosphere numerical model (UAM) data for three days that differ in the amplitude and the character of solar and magnetic activity and correspond to quiet and moderately disturbed states of the ionosphere. The work was performed in order to improve the methods for determining the ionospheric state by vertical sounding ionograms. The time variations in the F2 layer critical frequency, electric field vector zonal component, and thermospheric wind velocity meridional component have been analyzed. Calculations were performed with three UAM variants. The UAM version providing the best agreement with the CADI ionosonde data was the version in which the neutral temperature, neutral composition, and pressure gradients are calculated according to the MSIS empirical model and the horizontal neutral wind velocity is determined by the equation of motion with pressure gradients from MSIS. The calculated values corresponded to the measurements, except those for the evening, because the electron density at the ionospheric F2 layer maximum depends more strongly on electric fields and thermospheric wind velocities during this period. Thus, the indicated UAM version with the above limitations can be used to determine the state of the subauroral ionosphere.

  19. Georgia Basin-Puget Sound Airshed Characterization Report 2014

    EPA Science Inventory

    The Georgia Basin - Puget Sound Airshed Characterization Report, 2012 was undertaken to characterize the air quality within the Georgia Basin/Puget Sound region,a vibrant, rapidly growing, urbanized area of the Pacific Northwest. The Georgia Basin - Puget Sound Airshed Characteri...

  20. On the construction, comparison, and variability of airsheds for interpreting semivolatile organic compounds in passively sampled air.

    PubMed

    Westgate, John N; Wania, Frank

    2011-10-15

    Air mass origin as determined by back trajectories often aids in explaining some of the short-term variability in the atmospheric concentrations of semivolatile organic contaminants. Airsheds, constructed by amalgamating large numbers of back trajectories, capture average air mass origins over longer time periods and thus have found use in interpreting air concentrations obtained by passive air samplers. To explore some of their key characteristics, airsheds for 54 locations on Earth were constructed and compared for roundness, seasonality, and interannual variability. To avoid the so-called "pole problem" and to simplify the calculation of roundness, a "geodesic grid" was used to bin the back-trajectory end points. Departures from roundness were seen to occur at all latitudes and to correlate significantly with local slope but no strong relationship between latitude and roundness was revealed. Seasonality and interannual variability vary widely enough to imply that static models of transport are not sufficient to describe the proximity of an area to potential sources of contaminants. For interpreting an air measurement an airshed should be generated specifically for the deployment time of the sampler, especially when investigating long-term trends. Samples taken in a single season may not represent the average annual atmosphere, and samples taken in linear, as opposed to round, airsheds may not represent the average atmosphere in the area. Simple methods are proposed to ascertain the significance of an airshed or individual cell. It is recommended that when establishing potential contaminant source regions only end points with departure heights of less than ∼700 m be considered.

  1. Lumping, testing, tuning: The invention of an artificial chemistry in atmospheric transport modeling

    NASA Astrophysics Data System (ADS)

    Heymann, Matthias

    Since the late 1950s computer simulation has been used to investigate the transport of pollutants in the atmosphere. About 20 years later also the chemical transformation of atmospheric pollutants was included in computer models of photochemical smog formation. Due to limited knowledge of atmospheric chemistry and due to limited computer capacity, chemical processes in the atmosphere were modeled with the help of simplified chemical models. In these models chemical substances are lumped together forming artificial virtual compounds with virtual characteristics. The paper aims at studying the practices developed in chemical model building and the creation of confidence in these models. Core of the paper will be the analysis of the Urban Airshed Model (UAM) for the Los Angeles region, a pioneering development in the early 1970s. The construction of the UAM involved the "lumping" of chemical processes and extensive testing and tuning. These practices led to a consistent model representation, in which diverse pieces of information fitted and were mutually stabilized. The pragmatic achievement of consistency created confidence, even though empirical tests of the models remained ambiguous and problematic.

  2. Model simulation of meteorology and air quality during the summer PUMA intensive measurement campaign in the UK West Midlands conurbation.

    PubMed

    Baggott, Sarah; Cai, Xiaoming; McGregor, Glenn; Harrison, Roy M

    2006-05-01

    The Regional Atmospheric Modeling System (RAMS) and Urban Airshed Model (UAM IV) have been implemented for prediction of air pollutant concentrations within the West Midlands conurbation of the United Kingdom. The modelling results for wind speed, direction and temperature are in reasonable agreement with observations for two stations, one in a rural area and the other in an urban area. Predictions of surface temperature are generally good for both stations, but the results suggest that the quality of temperature prediction is sensitive to whether cloud cover is reproduced reliably by the model. Wind direction is captured very well by the model, while wind speed is generally overestimated. The air pollution climate of the UK West Midlands is very different to those for which the UAM model was primarily developed, and the methods used to overcome these limitations are described. The model shows a tendency towards under-prediction of primary pollutant (NOx and CO) concentrations, but with suitable attention to boundary conditions and vertical profiles gives fairly good predictions of ozone concentrations. Hourly updating of chemical concentration boundary conditions yields the best results, with input of vertical profiles desirable. The model seriously underpredicts NO2/NO ratios within the urban area and this appears to relate to inadequate production of peroxy radicals. Overall, the chemical reactivity predicted by the model appears to fall well below that occurring in the atmosphere.

  3. Model simulation of meteorology and air quality during the summer PUMA intensive measurement campaign in the UK West Midlands conurbation.

    PubMed

    Baggott, Sarah; Cai, Xiaoming; McGregor, Glenn; Harrison, Roy M

    2006-05-01

    The Regional Atmospheric Modeling System (RAMS) and Urban Airshed Model (UAM IV) have been implemented for prediction of air pollutant concentrations within the West Midlands conurbation of the United Kingdom. The modelling results for wind speed, direction and temperature are in reasonable agreement with observations for two stations, one in a rural area and the other in an urban area. Predictions of surface temperature are generally good for both stations, but the results suggest that the quality of temperature prediction is sensitive to whether cloud cover is reproduced reliably by the model. Wind direction is captured very well by the model, while wind speed is generally overestimated. The air pollution climate of the UK West Midlands is very different to those for which the UAM model was primarily developed, and the methods used to overcome these limitations are described. The model shows a tendency towards under-prediction of primary pollutant (NOx and CO) concentrations, but with suitable attention to boundary conditions and vertical profiles gives fairly good predictions of ozone concentrations. Hourly updating of chemical concentration boundary conditions yields the best results, with input of vertical profiles desirable. The model seriously underpredicts NO2/NO ratios within the urban area and this appears to relate to inadequate production of peroxy radicals. Overall, the chemical reactivity predicted by the model appears to fall well below that occurring in the atmosphere. PMID:16266739

  4. Biomedical Engineering curriculum at UAM-I: a critical review.

    PubMed

    Martinez Licona, Fabiola; Azpiroz-Leehan, Joaquin; Urbina Medal, E Gerardo; Cadena Mendez, Miguel

    2014-01-01

    The Biomedical Engineering (BME) curriculum at Universidad Autónoma Metropolitana (UAM) has undergone at least four major transformations since the founding of the BME undergraduate program in 1974. This work is a critical assessment of the curriculum from the point of view of its results as derived from an analysis of, among other resources, institutional databases on students, graduates and their academic performance. The results of the evaluation can help us define admission policies as well as reasonable limits on the maximum duration of undergraduate studies. Other results linked to the faculty composition and the social environment can be used to define a methodology for the evaluation of teaching and the implementation of mentoring and tutoring programs. Changes resulting from this evaluation may be the only way to assure and maintain leadership and recognition from the BME community.

  5. Atmospheric speciation of mercury in two contrasting Southeastern US airsheds

    NASA Astrophysics Data System (ADS)

    Gabriel, Mark C.; Williamson, Derek G.; Brooks, Steve; Lindberg, Steve

    Simultaneous measurement of gaseous elemental, reactive gaseous, and fine particulate mercury took place in Tuscaloosa AL, (urban airshed) and Cove Mountain, TN (non-urban airshed) during the summers of 2002 and 2003. The objective of this research was to (1) summarize the temporal distribution of each mercury specie at each site and compare to other speciation data sets developed by other researchers and (2) provide insight into urban and non-urban mercury speciation effects using various statistical methods. Average specie concentrations were as follows: 4.05 ng m -3 (GEM), 13.6 pg m -3 (RGM), 16.4 pg m -3 (Hg-p) for Tuscaloosa; 3.20 ng m -3 (GEM), 13.6 pg m -3 (RGM), 9.73 pg m -3 (Hg-p) for Cove Mountain. As a result of urban airshed impacts, short periods of high concentration for all mercury species was common in Tuscaloosa. At Cove Mountain a consistent mid-day rise and evening drop for mercury species was found. This pattern was primarily the result of un-impacted physical boundary layer movement, although, other potential impacts were ambient photochemistry and air-surface exchange of mercury. Meteorological parameters that are known to heavily impact mercury speciation were similar for the study period for Tuscaloosa and Cove Mountain except for wind speed (m s -1), which was higher at Cove Mountain. For both sites statistically significant ( p<0.0001), inverse relationships existed between wind speed and Hg 0 concentration. A weaker windspeed-Hg 0 correlation existed for Tuscaloosa. By analyzing Hg concentration—wind speed magnitude change at both sites it was found that wind speed at Cove Mountain had a greater influence on Hg 0 concentration variability than Tuscaloosa by a factor of 3. Using various statistical tests, we concluded that the nature of Tuscaloosa's atmospheric mercury speciation was the result of typical urban airshed impacts. Cove Mountain showed atmospheric mercury speciation characteristics indicative of a non-urban area along with

  6. Air Quality in the Puebla-Tlaxcala Airshed in Mexico during April 2009

    NASA Astrophysics Data System (ADS)

    Ruiz Suarez, L. G.; Torres Jardón, R.; Torres Jaramillo, J. A.; Barrera, H.; Castro, T.; Mar Morales, B. E.; García Reynoso, J. A.; Molina, L. T.

    2012-04-01

    East of the Mexico Megacity, is the metropolitan area of Puebla-Tlaxcala which is reproducing the same patterns of urban sprawl as in the Mexico City Metropolitan Area. Is an area of high industrial density, the fragmented urban sprawl boost the use of particular cars in detrimental of public transport use. Emissions inventories reflect this fact; they also show a considerable use of biomass energy in households and small using a set of industries and service business. In April 2009 we carried out a preliminary field campaign in the basin, we deployed three mobile units, one in the north, in a site connecting with the valley of Mexico basin, one in the south where it may connect with the Cuautla-Cuernavaca Airshed and one in a receptor site to the Puebla Metropolitan Area. In addition to the available data from local air quality network within the City of Puebla. Analysis of the 2009 data show a complex flow pattern induced by the Popocateptl and Iztaccihuatl volcanoes to the west and La Malinche volcano to the east. Excess NOx emissions in the urban and industrial core lead to very low ozone levels within but high ozone concentrations are observed in the peri-urban and rural areas, exceeding the Mexican Air Quality Standards. In our presentation we will describe and explain these observations and will describe a field campaign to be carried out in March-April 2012 aiming to better document the air quality in the Puebla-Tlaxcala Airshed. Hybrid observation-model maps for ozone critical levels show the population exposed to exeedences to the official standards. AOT40 maps also show that crops and forests in the region are exposed to unhealthy ozone levels. These results add to those from MILAGRO and CARIEM field campaigns on the regional scale of the air quality issues in central Mexico. A point is made on the need to update the Mexicp Air Quality Standard for ozone.

  7. Modeling ozone episodes in the Baltimore-Washington region

    NASA Technical Reports Server (NTRS)

    Ryan, William F.

    1994-01-01

    Surface ozone (O3) concentrations in excess of the National Ambient Air Quality Standard (NAAQS) continue to occur in metropolitan areas in the United States despite efforts to control emissions of O3 precursors. Future O3 control strategies will be based on results from modeling efforts that have just begun in many areas. Two initial questions that arise are model sensitivity to domain-specific conditions and the selection of episodes for model evaluation and control strategy development. For the Baltimore-Washington region (B-W), the presence of the Chesapeake Bay introduces a number of issues relevant to model sensitivity. In this paper, the specific questions of the determination of model volume (mixing height) for the Urban Airshed Model (UAM) is discussed and various alternative methods compared. For the latter question, several analytic approaches, Cluster Analysis and classification and Regression Tree (CART) analysis are undertaken to determine meteorological conditions associated with severe O3 events in the B-W domain.

  8. Formaldehyde and its relation to CO, PAN, and SO2 in the Houston-Galveston airshed

    NASA Astrophysics Data System (ADS)

    Rappenglück, B.; Dasgupta, P. K.; Leuchner, M.; Li, Q.; Luke, W.

    2010-03-01

    The Houston-Galveston Airshed (HGA) is one of the major metropolitan areas in the US that is classified as a nonattainment area of federal ozone standards. Formaldehyde (HCHO) is a key species in understanding ozone related air pollution; some of the highest HCHO concentrations in North America have been reported for the HGA. We report on HCHO measurements in the HGA from summer 2006. Among several sites, maximum HCHO mixing ratios were observed in the Houston Ship Channel (HSC), a region with a very high density of industrial/petrochemical operations. HCHO levels at the Moody Tower (MT) site close to downtown were dependent on the wind direction: southerly maritime winds brought in background levels (0.5-1 ppbv) while trajectories originating in the HSC resulted in high HCHO (up to 31.5 ppbv). Based on the best multiparametric linear regression model fit, the HCHO levels at the MT site can be accounted for as follows: 38.5±12.3% from primary vehicular emissions (using CO as an index of vehicular emission), 24.1±17.7% formed photochemically (using peroxyacetic nitric anhydride (PAN) as an index of photochemical activity) and 8.9±11.2% from industrial emissions (using SO2 as an index of industrial emissions). The balance 28.5±12.7% constituted the residual which cannot be easily ascribed to the above categories and/or which is transported into the HGA. The CO related HCHO fraction is dominant during the morning rush hour (06:00-09:00 h, all times are given in CDT); on a carbon basis, HCHO emissions are up to 0.7% of the CO emissions. The SO2 related HCHO fraction is significant between 09:00-12:00 h. After 12:00 h HCHO is largely formed through secondary processes. The HCHO/PAN ratios are dependent on the SO2 levels. The SO2 related HCHO fraction at the downtown site originates in the ship channel. Aside from traffic-related primary HCHO emissions, HCHO of industrial origin serves as an appreciable source for OH in the morning.

  9. Formaldehyde and its relation to CO, PAN, and SO2 in the Houston-Galveston airshed

    NASA Astrophysics Data System (ADS)

    Rappenglück, B.; Dasgupta, P. K.; Leuchner, M.; Li, Q.; Luke, W.

    2009-11-01

    The Houston-Galveston Airshed (HGA) is one of the major metropolitan areas in the US that is classified as a nonattainment area of Federal ozone standards. Formaldehyde (HCHO) is a key species in understanding ozone related air pollution; some of the highest HCHO concentrations in North America have been reported for the HGA. We report on HCHO measurements in the HGA from summer 2006. Among several sites, maximum HCHO mixing ratios were observed in the Houston Ship Channel (HSC), a region with a very high density of industrial/petrochemical operations. HCHO levels at the Moody Tower (MT) site close to downtown were dependent on the wind direction: southerly maritime winds brought in background levels (0.5-1 ppbv) while trajectories originating in the HSC resulted in high HCH (up to 31.5 ppbv). Based on the best multiparametric linear regression model fit, the HCHO levels at the MT site can be accounted for as follows: 38.5±12.3% from primary vehicular emissions (using CO as an index of vehicular emission), 24.1±17.7% formed photochemically (using peroxyacetic nitric anhydride (PAN) as an index of photochemical activity) and 8.9±11.2% from industrial emissions (using SO2 as an index of industrial emissions). The balance 28.5±12.7% constituted the residual which cannot be easily ascribed to the above categories and/or which is transported into the HGA. The CO related HCHO fraction is dominant during the morning rush hour (06:00-09:00 h, all times are given in CDT); on a carbon basis, HCHO emissions are up to 0.7% of the CO emissions. The SO2 related HCHO fraction is significant between 09:00-12:00 h. After 12:00 h HCHO is largely formed through secondary processes. The HCHO/PAN ratios are dependent on the SO2 levels. The SO2 related HCHO fraction at the downtown site originates in the ship channel. Aside from traffic-related primary HCHO emissions, HCHO of industrial origin serves as an appreciable source for OH in the morning.

  10. Exposure and risk from ambient particle-bound pollution in an airshed dominated by residential wood combustion and mobile sources.

    PubMed Central

    Cupitt, L T; Glen, W G; Lewtas, J

    1994-01-01

    A major field study was conducted in Boise, Idaho, during the heating season of 1986 to 1987 as part of the Integrated Air Cancer Project. Filter samples were systematically collected in residences and in the ambient air across the community to characterize the particle-bound pollutants. The extractable organic matter (EOM) from the filter samples was apportioned to its source of origin, either residential wood combustion (RWC) or mobile sources (MS). Two composite samples, with apportioned contributions from RWC and MS, were prepared from the Boise ambient samples and tested for tumor-initiation potency. A comparative potency lung cancer risk estimate has been made based on the two ambient composite samples from this airshed. In addition, a microenvironmental exposure model was developed from the Boise data and from national survey data to estimate the exposure to EOM from RWC and MS. In this paper, the microenvironmental model is extrapolated to provide an estimate of the average annual exposure and dose in Boise to EOM from RWC and MS. The annual model considers actual pollutant levels in Boise, historical changes in RWC usage and meteorological dilution factors and the likely activities in the various microenvironmental zones and their resultant inhalation rates. Combined with the lifetime risk estimates, the average annual dose suggests a risk of about 4 x 10(-4) based upon the composite ambient samples. Despite the fact that RWC accounts for 73% of the EOM on an annual average basis, it accounts for only about 20% of the estimated lifetime risk. PMID:7529707

  11. Staphylococcus aureus ClpC divergently regulates capsule via sae and codY in strain newman but activates capsule via codY in strain UAMS-1 and in strain Newman with repaired saeS.

    PubMed

    Luong, Thanh T; Sau, Keya; Roux, Christelle; Sau, Subrata; Dunman, Paul M; Lee, Chia Y

    2011-02-01

    ClpC is an ATPase chaperone found in most Gram-positive low-GC bacteria. It has been recently reported that ClpC affected virulence gene expression in Staphylococcus aureus. Here we report that ClpC regulates transcription of the cap operon and accumulation of capsule, a major virulence factor for S. aureus. As virulence genes are regulated by a complex regulatory network in S. aureus, we have used capsule as a model to understand this regulation. By microarray analyses of strain Newman, we found that ClpC strongly activates transcription of the sae operon, whose products are known to negatively regulate capsule synthesis in this strain. Further studies indicated that ClpC repressed capsule production by activating the sae operon in strain Newman. Interestingly, the clpC gene cloned into a multiple-copy plasmid vector exhibited an activation phenotype, suggesting that ClpC overexpression has a net positive effect. In the absence of sae function, by either deletion or correction of a native mutation within saeS, we found that ClpC had a positive effect on capsule production. Indeed, in the UAMS-1 strain, which does not have the saeS mutation, ClpC functioned as an activator of capsule production. Our microarray analyses of strain Newman also revealed that CodY, a repressor of capsule production, was repressed by ClpC. Using genetic approaches, we showed that CodY functioned downstream of ClpC, leading to capsule activation both in Newman and in UAMS-1. Thus, ClpC functions in two opposite pathways in capsule regulation in strain Newman but functions as a positive activator in strain UAMS-1.

  12. Effect of cadmium on the bioelement composition of Nostoc UAM208: Interaction with calcium

    SciTech Connect

    Fernandez-Pinas, F.; Mateo, P.; Bonilla, I.

    1997-04-01

    Heavy metals may cause effects on the cyanobacterial cell including possible damage to the membranes and leakage from cells resulting in the loss or reduction of essential bioelements. There are many reports in the literature concerning morphological, biochemical and physiological changes caused by cadmium in cyanobacteria, but data on the influence of cadmium on the ion balance of the cell dealing with the interactive effect of cadmium and calcium are limited. Calcium has been found to exert a protective role against heavy metal toxicity in a variety of organisms, We previously reported that calcium is able to counteract the toxic effect of cadmium towards growth, photosynthesis, nitrogenase activity and pigment content of the cyanobacterium Nostoc UAM208. In the present study, we analyzed the content of essential ions, as affected by cadmium treatment, to search for possible mechanisms of heavy metal damage and toxicity in Nostoc. We also studied whether calcium enrichment (1.1 mM final concentration) has any influence on the heavy metal effect on those ionic contents. 13 refs., 2 figs.

  13. Potential impacts of Title I nonattainment on the electric power industry: A Chicago case study (Phase 2)

    SciTech Connect

    Fernau, M.E.; Makofske, W.J.; South, D.W.

    1993-06-01

    This study uses version IV of the Urban Airshed Model (UAM-IV) to examine the potential impacts of Title I (nonattainment) and Title IV (acid rain) of the Clean Air Act Amendments of 1990 (CAAA) on the utility industry. The UAM is run for a grid that covers the Commonwealth Edison Power Pool and encompasses the greater Chicago area and surrounding rural areas. Meteorological conditions are selected from an ozone (O{sub 3}) episode on July 5 and 6, 1988.

  14. Understanding the Evolution of Organic Aerosols in the Mexico City Airshed in 2002, 2003 and 2006 using Positive Matrix Factorization

    NASA Astrophysics Data System (ADS)

    Ulbrich, I. M.; Dzepina, K.; Canagaratna, M.; Zhang, Q.; Decarlo, P.; Salcedo, D.; Aiken, A. C.; Onasch, T. B.; Allan, J.; Russell, L. M.; Grivicke, R.; Lamb, B.; Alexander, M. L.; Worsnop, D. R.; Jimenez, J.

    2008-12-01

    Aerosol mass spectrometric measurements yield spectra of ambient aerosols that are a mix of various primary and secondary sources. Organic aerosol (OA) datasets acquired using Aerodyne aerosol mass spectrometers (Q-AMS, C-ToF-AMS, and HR-ToF-AMS) deployed in 2002, 2003, and 2006 in the Mexico City Metropolitan Area (MCMA) at multiple ground locations and from aircraft flights are analyzed with Positive Matrix Factorization to deconvolve information about important sources and processes for organic aerosols. Several components are identified in each dataset. Most datasets resolve contributions from: reduced (oxidative state) hydrocarbon-like OA (HOA), which correlates well with primary combustion tracers such as CO, NOx, and BC; biomass burning OA (BBOA), which correlates with regional fire counts, potassium, levoglucosan, acetonitrile, and HCN; highly-oxidized OA (OOA-I) which shows more regional behavior; and less oxidized OA (OOA-II) which correlates with semivolatile inorganic species such as ammonium nitrate and gas-phase secondary species such as Ox (NO2 + O3) and glyoxal. These correlations are consistent across most datasets when run separately in PMF. Factor spectra are also compared to reference spectra, and ratios of factor concentrations to relevant tracers (e.g., HOA/CO, OOA/Ox) are presented. Factor spectra, time series, diurnal cycles, and ratios are compared at sampling locations across the MCMA and in different years in order to understand the evolution of OA across the airshed. The effect of running multiple datasets within a single PMF model (e.g., simultaneous measurements made at two locations in Mexico City), and the stability of PMF solutions will be described.

  15. Photochemical smog modeling for assessment of potential impacts of different management strategies on air quality of the Bangkok Metropolitan Region, Thailand.

    PubMed

    Oanh, Nguyen Thi Kim; Zhang, Baoning

    2004-10-01

    A photochemical smog model system, the Variable-Grid Urban Airshed Model/Systems Applications International Mesoscale Model (UAM-V/SAIMM), was used to investigate photochemical pollution in the Bangkok Metropolitan Region (BMR). The model system was first applied to simulate a historical photochemical smog episode of two days (January 13-14, 1997) using the 1997 anthropogenic emission database available at the Pollution Control Department and an estimated biogenic emission. The output 1-hr ozone (O3) for BMR, however, did not meet the U.S. Environmental Protection Agency suggested performance criteria. The simulated minimum and maximum O3 values in the domain were much higher than the observations. Multiple model runs with different precursor emission reduction scenarios showed that the best model performance with the simulated 1-hr O3 meeting all the criteria was obtained when the volatile organic compound (VOC) and oxides of nitrogen (NOx) emission from mobile source reduced by 50% and carbon monoxide by 20% from the original database. Various combinations of anthropogenic and biogenic emissions in Bangkok and surrounding provinces were simulated to assess the contribution of different sources to O3 pollution in the city. O3 formation in Bangkok was found to be more VOC-sensitive than NOx-sensitive. To attain the Thailand ambient air quality standard for 1-hr O3 of 100 ppb, VOC emission in BMR should be reduced by 50-60%. Management strategies considered in the scenario study consist of Stage I, Stage II vapor control, replacement of two-stroke by four-stroke motorcycles, 100% compressed natural gas bus, 100% natural gas-fired power plants, and replacement of methyltertiarybutylether by ethanol as an additive for gasoline.

  16. Quantification of Wood Smoke Markers in Fine Atmospheric PM in the New York City Airshed

    NASA Astrophysics Data System (ADS)

    Hawley, H. A.; Mazurek, M. A.; Li, M.

    2007-12-01

    Seasonal emissions from residential wood combustion, natural wildfires, agricultural burning and solid waste combustion are considered to be major sources of fine particles to the NYC metropolitan airshed. Wood smoke produced from the combustion of cellulosic material consists of polar organic compounds which are highly water-soluble. As alternative forms of energy production including biofuels for residential heating are developed and become more widely used, a key science question is how much of the carbonaceous PM2.5 currently is from wood smoke in urbanized areas and to what extent is this influencing atmospheric chemical properties. This project focuses on the quantitation of polar organic compounds extracted from fine particle samples (PM2.5) collected as part of the Speciation of Organics for Apportionment of PM-2.5 in the New York City Area (SOAP). The SOAP network operated from May 2002 to May 2003 at four sites: Queens, NYC (high density urban residential); Elizabeth, NJ (adjacent to the NJ Turnpike); Westport, CT (downwind NYC residential); and a regional background site in Chester, NJ (upwind NYC). A quantitative extraction and gas chromatographic/mass spectrometric (GC/MS) chemical analysis procedure was developed and evaluated. Trimethylsilyl (TMS) derivatives were prepared prior to GC/MS analysis and 5-point calibrations and multiple replicates were evaluated to ensure method precision. Levoglucosan was used as the primary marker for cellulose combustion; however a suite of monosaccharides and disaccharides and dehydroabietic acid, a marker indicative of soft wood combustion, also were quantified. Levoglucosan was found during each season at all four sampling locations with ambient mass concentrations ranging from 2.36 ng/m3 to 189 ng/m3. These values represent an estimated low of 0.73 percent to a high of 69 percent of organic carbon in the fine PM from wood smoke. The lowest levoglucosan concentrations were present consistently at the Chester, NJ

  17. Survey of volatile organic compounds associated with automotive emissions in the urban airshed of São Paulo, Brazil

    NASA Astrophysics Data System (ADS)

    Colón, Maribel; Pleil, Joachim D.; Hartlage, Thomas A.; Lucia Guardani, M.; Helena Martins, M.

    The Metropolitan Region of São Paulo (MRSP), Brazil, is one of the largest metropolitan areas in the world (population 17 million, approx.) and relies heavily on alcohol-based fuels for automobiles. It is estimated that about 40% of the total volume of fuel is ethanol with some vehicles using pure ethanol and others a gasoline/ethanol blend. As such, São Paulo is an excellent example of an oxygenates-dominated airshed of mobile sources and is most likely indicative of the future in heavily populated areas in the US such as Los Angeles where "oxy-fuels" are becoming an important replacement for the conventional pure petroleum-based fuels. In this work, we surveyed the ambient air to identify and quantify the organic compounds associated with the evaporative and exhaust emissions of these fuels and to begin to understand the potential for human exposure. Because this was an initial test without detailed prior knowledge of the airshed of the area, we applied two different air sampling methods for various time periods to assess the ambient concentrations of a variety of polar and nonpolar volatile organic compounds (VOCs). For quality assurance (QA), we collected all the samples in duplicate (whole-air samples in Summa canisters and adsorbent-based samples on Perkin-Elmer Air Toxics tubes) at various flow rates to test performance. All samples were collected over identical time frames, typically for 1-, 2-, and 4-h periods per day at six different locations over a period of 1 week. Overall São Paulo results demonstrate that mean concentrations of single-ring aromatics are 2-3 times higher, volatile aldehydes are 5-10 times higher, and simple alcohols 10-100 times higher as compared to results of a recent study performed by EPA in the Los Angeles basin. C 4-C 11n-alkanes were only slightly elevated in São Paulo.

  18. Using Sediment Records to Reconstruct Historical Inputs Combustion-Derived Contaminants to Urban Airsheds/Watersheds: A Case Study From the Puget Sound

    NASA Astrophysics Data System (ADS)

    Louchouarn, P. P.; Kuo, L.; Brandenberger, J.; Marcantonio, F.; Wade, T. L.; Crecelius, E.; Gobeil, C.

    2008-12-01

    Urban centers are major sources of combustion-derived particulate matter (e.g. black carbon (BC), polycyclic aromatic hydrocarbons (PAH), anhydrosugars) and volatile organic compounds to the atmosphere. Evidence is mounting that atmospheric emissions from combustion sources remain major contributors to air pollution of urban systems. For example, recent historical reconstructions of depositional fluxes for pyrogenic PAHs close to urban systems have shown an unanticipated reversal in the trends of decreasing emissions initiated during the mid-20th Century. Here we compare a series of historical reconstructions of combustion emission in urban and rural airsheds over the last century using sedimentary records. A complex suite of combustion proxies (BC, PAHs, anhydrosugars, stable lead concentrations and isotope signatures) assisted in elucidating major changes in the type of atmospheric aerosols originating from specific processes (i.e. biomass burning vs. fossil fuel combustion) or fuel sources (wood vs. coal vs. oil). In all studied locations, coal continues to be a major source of combustion-derived aerosols since the early 20th Century. Recently, however, oil and biomass combustion have become substantial additional sources of atmospheric contamination. In the Puget Sound basin, along the Pacific Northwest region of the U.S., rural locations not impacted by direct point sources of contamination have helped assess the influence of catalytic converters on concentrations of oil-derived PAH and lead inputs since the early 1970s. Although atmospheric deposition of lead has continued to drop since the introduction of catalytic converters and ban on leaded gasoline, PAH inputs have "rebounded" in the last decade. A similar steady and recent rise in PAH accumulations in urban systems has been ascribed to continued urban sprawl and increasing vehicular traffic. In the U.S., automotive emissions, whether from gasoline or diesel combustion, are becoming a major source of

  19. Aryl hydrocarbon receptor-mediated activity of particulate organic matter from the Paso del Norte airshed along the U.S.-Mexico border.

    PubMed Central

    Arrieta, Daniel E; Ontiveros, Cynthia C; Li, Wen-Whai; Garcia, Jose H; Denison, Michael S; McDonald, Jacob D; Burchiel, Scott W; Washburn, Barbara Shayne

    2003-01-01

    In this study, we determined the biologic activity of dichloromethane-extracted particulate matter < 10 micro m in aerodynamic diameter (PM10) obtained from filters at three sites in the Paso del Norte airshed, which includes El Paso, Texas, USA; Juarez, Chihuahua, Mexico, and Sunland Park, New Mexico, USA. The extracts were rich in polycyclic aromatic hydrocarbons (PAHs) and had significant biologic activity, measured using two in vitro assay systems: ethoxyresorufin-(O-deethylase (EROD) induction and the aryl hydrocarbon-receptor luciferase reporter system. In most cases, both EROD (5.25 pmol/min/mg protein) and luciferase activities (994 relative light units/mg) were highest in extracts from the Advance site located in an industrial neighborhood in Juarez. These values represented 58% and 55%, respectively, of induction associated with 1 micro M ss-naphthoflavone exposures. In contrast, little activity was observed at the Northeast Clinic site in El Paso, the reference site. In most cases, luciferase and EROD activity from extracts collected from the Tillman Health Center site, situated in downtown El Paso, fell between those observed at the other two sites. Overall, a statistically significant correlation existed between PM10 and EROD and luciferase activities. Chemical analysis of extracts collected from the Advance site demonstrated that concentrations of most PAHs were higher than those reported in most other metropolitan areas in the United States. Calculations made with these data suggest a cancer risk of 5-12 cases per 100,000 people. This risk estimate, as well as comparisons with the work of other investigators, raises concern regarding the potential for adverse health effects to the residents of this airshed. Further work is needed to understand the sources, exposure, and effects of PM10 and particulate organic material in the Paso del Norte airshed. PMID:12896850

  20. Final Report of the Grant: ''Vertical Transport and Mixing in Complex Terrain Airsheds''

    SciTech Connect

    Fernando, Joseph Harindra; Anderson, James; Boyer, Don; Berman, Neil

    2004-12-29

    Stable stratification associated with nocturnal thermal circulation in areas of complex terrain leads to interesting and important phenomena that govern local meteorology and contaminant dispersion. Given that most urban areas are in complex topography, understanding and prediction of such phenomena are of immediate practical importance. This project dealt with theoretical, laboratory, numerical and field experimental studies aimed at understanding stratified flow and turbulence phenomena in urban areas, with particular emphasis on flow, turbulence and contaminant transport and diffusion in such flows. A myriad of new results were obtained and some of these results were used to improve the predictive capabilities of the models.

  1. Aerosol characterizaton in El Paso-Juarez airshed using optical methods

    NASA Astrophysics Data System (ADS)

    Esparza, Angel Eduardo

    2011-12-01

    The assessment and characterization of atmospheric aerosols and their optical properties are of great significance for several applications such as air pollution studies, atmospheric visibility, remote sensing of the atmosphere, and impacts on climate change. Decades ago, the interest in atmospheric aerosols was primarily for visibility impairment problems; however, recently interest has intensified with efforts to quantify the optical properties of aerosols, especially because of the uncertainties surrounding the role of aerosols in climate change. The main objective of the optical characterization of aerosols is to understand their properties. These properties are determined by the aerosols' chemical composition, size, shape and concentration. The general purpose of this research was to contribute to a better characterization of the aerosols present in the Paso del Norte Basin. This study permits an alternative approach in the understanding of air pollution for this zone by analyzing the predominant components and their contributions to the local environment. This dissertation work had three primary objectives, in which all three are intertwined by the general purpose of the aerosol characterization in the Paso del Norte region. The first objective was to retrieve the columnar aerosol size distribution for two different cases (clean and polluted scenarios) at each season (spring, summer, fall and winter) of the year 2009. In this project, instruments placed in buildings within the University of Texas at El Paso (UTEP) as well as a monitoring site (CAMS 12) from the Texas Commission on Environmental Quality (TCEQ) provided the measurements that delimited the aerosol size distribution calculated by our model, the Environmental Physics Inverse Reconstruction (EPIRM) model. The purpose of this objective was to provide an alternate method of quantifying and size-allocating aerosols in situ, by using the optical properties of the aerosols and inversely reconstruct and

  2. Associations between immune function and air pollution among postmenopausal women living in the Puget Sound airshed

    NASA Astrophysics Data System (ADS)

    Williams, Lori A.

    Air pollution is associated with adverse health outcomes, and changes in the immune system may be intermediate steps between exposure and a clinically relevant adverse health outcome. We analyzed the associations between three different types of measures of air pollution exposure and five biomarkers of immune function among 115 overweight and obese postmenopausal women whose immunity was assessed as part of a year-long moderate exercise intervention trial. For air pollution metrics, we assessed: (1) residential proximity to major roads (freeways, major arterials and truck routes), (2) fine particulate matter(PM2.5) at the nearest monitor to the residence averaged over three time windows (3-days, 30-days and 60-days), and (3) nitrogen dioxide (NO2) modeled based on land use characteristics. Our immune biomarkers included three measures of inflammation---C-reactive protein, serum amyloid A and interleukin-6---and two measures of cellular immunity---natural killer cell cytotoxicity and T lymphocyte proliferation. We hypothesized that living near a major road, increased exposure to PM2.5 and increased exposure to NO2 would each be independently associated with increased inflammation and decreased immune function. We observed a 21% lower average natural killer cell cytotoxicity among women living within 150 meters of a major arterial road compared to other women. For PM2.5 , we observed changes in 3 of 4 indicators of lymphocyte proliferation stimulated by anti-CD3---an antibody to the T cell receptor associated with increases in 3-day averaged PM2.5. For 30-day averaged PM 2.5 and 60-day averaged PM2.5 we did not observe any statistically significant associations. We observed an increase in lymphocyte proliferation index stimulated by the plant protein phytohemagglutinin (PHA) at 1 of 2 PHA concentrations in association with modeled NO2. For the three inflammatory markers, we observed no notable associations with any of our measures of air pollution. If confirmed, our

  3. RECEPTOR MODEL COMPARISONS AND WIND DIRECTION ANALYSES OF VOLATILE ORGANIC COMPOUNDS AND SUBMICROMETER PARTICLES IN AN ARID, BINATIONAL, URBAN AIRSHED

    EPA Science Inventory

    The relationship between continuous measurements of volatile organic compounds sources and particle number was evaluated at a Photochemical Assessment Monitoring Station Network (PAMS) site located near the U.S.-Mexico Border in central El Paso, TX. Sources of volatile organic...

  4. AIRSHED DOMAINS FOR MODELING ATMOSPHERIC DEPOSITION OF OXIDIZED AND REDUCED NITROGEN TO THE NEUSE/PAMLICO SYSTEM OF NORTH CAROLINA

    EPA Science Inventory

    Atmospheric deposition is important to nutrient loadings to coastal estuaries. Atmospheric emissions of nitrogen travel hundreds of kilometers as they are removed via atmospheric deposition. Long-range transport from outside the Neuse/Pamlico system in North Carolina is an impo...

  5. EVALUATING THE PERFORMANCE OF REGIONAL-SCALE PHOTOCHEMICAL MODELING SYSTEMS: PART II--OZONE PREDICTIONS. (R825260)

    EPA Science Inventory

    In this paper, the concept of scale analysis is applied to evaluate ozone predictions from two regional-scale air quality models. To this end, seasonal time series of observations and predictions from the RAMS3b/UAM-V and MM5/MAQSIP (SMRAQ) modeling systems for ozone were spectra...

  6. Trends in emissions and concentrations of air pollutants in the lower troposphere in the Baltimore/Washington airshed from 1997 to 2011

    NASA Astrophysics Data System (ADS)

    He, H.; Stehr, J. W.; Hains, J. C.; Krask, D. J.; Doddridge, B. G.; Vinnikov, K. Y.; Canty, T. P.; Hosley, K. M.; Salawitch, R. J.; Worden, H. M.; Dickerson, R. R.

    2013-08-01

    Trends in the composition of the lower atmosphere (0-1500 m altitude) and surface air quality over the Baltimore/Washington area and surrounding states were investigated for the period from 1997 to 2011. We examined emissions of ozone precursors from monitors and inventories as well as ambient ground-level and aircraft measurements to characterize trends in air pollution. The US EPA Continuous Emissions Monitoring System (CEMS) program reported substantial decreases in emission of summertime nitrogen oxides (NOx) from power plants, up to ∼80% in the mid-Atlantic States. These large reductions in emission of NOx are reflected in a sharp decrease of ground-level concentrations of NOx starting around 2003. The decreasing trend of tropospheric column CO observed by aircraft is ∼0.8 Dobson unit (DU) per year, corresponding to ∼35 ppbv yr-1 in the lower troposphere (the surface to 1500 m above ground level). Satellite observations of long-term, near-surface CO show a ∼40% decrease over western Maryland between 2000 and 2011; the same magnitude is indicated by aircraft measurements above these regions upwind of the Baltimore/Washington airshed. With decreasing emissions of ozone precursors, the ground-level ozone in the Baltimore/Washington area shows a 0.6 ppbv yr-1 decrease in the past 15 yr. Since photochemical production of ozone is substantially influenced by ambient temperature, we introduce the climate penalty factor (CPF) into the trend analysis of long-term aircraft measurements. After compensating for inter-annual variations in temperature, historical aircraft measurements indicate that the daily net production of tropospheric ozone over the Baltimore/Washington area decreased from ∼20 ppbv day-1 in the late 1990s to ∼7 ppbv day-1 in the early 2010s during ozone season. A decrease in the long-term column ozone is observed as ∼0.2 DU yr-1 in the lowest 1500 m, corresponding to an improvement of ∼1.3 ppbv yr-1. Our aircraft

  7. EVALUATING THE PERFORMANCE OF REGIONAL-SCALE PHOTOCHEMICAL MODELING SYSTEMS. PART III-PRECURSOR PREDICTIONS. (R825260)

    EPA Science Inventory

    Abstract

    Two regional-scale photochemical modeling systems, RAMS/UAM-V and MM5/MAQSIP, are used to simulate precursor concentrations for 4 June¯31 August 1995 period. The time series of simulated and observed precursor concentrations are spectrally deco...

  8. Cytotoxic responses and potential respiratory health effects of carbon and carbonaceous nanoparticulates in the Paso del Norte airshed environment.

    PubMed

    Soto, K F; Murr, L E; Garza, K M

    2008-03-01

    We have utilized a range of manufactured or commercial nanoparticulate materials, including surrogate carbon nano-PM along with combustion-generated carbonaceous (soot) nano-PM characteristic of environmental nano- PM (both indoor and outdoor) to investigate and compare their cytotoxic response in vitro with an immortalized human epithelial (lung model) cell line (A549). These have included nano-Ag, Al2O3, TiO2, Fe2O3, ZrO2, Si3N4, chrysotile asbestos, BC, 2 types of MWCNT-aggregate PM (MWCNT-R and MWCNT-N), and high-volume glass fiber collected soots: candle, wood, diesel (truck), tire, and 3-types of natural gas kitchen burner-generated soots: yellow (fuel-rich) flame, low-flow blue flame, and normal flow blue flame soot PM. These carbonaceous nano-PM species can be found in either the indoor and outdoor environments or microenvironments. Two-day and two-week in-vitro cultures of A549 showed cell death (or decreased cell viability) for all nanoparticulate materials, but especially significant for all but the TiO2 and candle, wood, and diesel PM. The natural gas kitchen burner combustion PM cell death response was characteristic of BC and MWCNT PM. There was no correlation with total PAH content of the soot PM. Cytokine release (IL-6, IL-8) was detected for the Ag, Fe2 O3, asbestos, BC and the MWCNT PM. Reactive oxygen species (ROS) production was also detected for Ag, Fe2 O3, ZrO2, asbestos, BC, and the MWCNT aggregate PM, as well as the natural gas kitchen burner combustion PM. TEM, FESEM, and optical microscopy examination of these nanomaterials illustrate the wide range in PM morphologies and crystallinities as well as cell morphologies. Taken together, these results illustrate proinflammatory and related respiratory health issues in relation to environmental nanoparticulates.

  9. Cytotoxic Responses and Potential Respiratory Health Effects of Carbon and Carbonaceous Nanoparticulates in the Paso del Norte Airshed Environment

    PubMed Central

    Soto, K. F.; Murr, L. E.; Garza, K. M.

    2008-01-01

    We have utilized a range of manufactured or commercial nanoparticulate materials, including surrogate carbon nano-PM along with combustion-generated carbonaceous (soot) nano-PM characteristic of environmental nano-PM (both indoor and outdoor) to investigate and compare their cytotoxic response in vitro with an immortalized human epithelial (lung model) cell line (A549). These have included nano-Ag, Al2O3, TiO2, Fe2O3, ZrO2, Si3N4, chrysotile asbestos, BC, 2 types of MWCNT-aggregate PM (MWCNT-R and MWCNT-N), and high-volume glass fiber collected soots: candle, wood, diesel (truck), tire, and 3-types of natural gas kitchen burner-generated soots: yellow (fuel-rich) flame, low-flow blue flame, and normal flow blue flame soot PM. These carbonaceous nano-PM species can be found in either the indoor and outdoor environments or microenvironments. Two-day and two-week in-vitro cultures of A549 showed cell death (or decreased cell viability) for all nanoparticulate materials, but especially significant for all but the TiO2 and candle, wood, and diesel PM. The natural gas kitchen burner combustion PM cell death response was characteristic of BC and MWCNT PM. There was no correlation with total PAH content of the soot PM. Cytokine release (IL-6, IL-8) was detected for the Ag, Fe2 O3, asbestos, BC and the MWCNT PM. Reactive oxygen species (ROS) production was also detected for Ag, Fe2 O3, ZrO2, asbestos, BC, and the MWCNT aggregate PM, as well as the natural gas kitchen burner combustion PM. TEM, FESEM, and optical microscopy examination of these nanomaterials illustrate the wide range in PM morphologies and crystallinities as well as cell morphologies. Taken together, these results illustrate proinflammatory and related respiratory health issues in relation to environmental nanoparticulates. PMID:18441401

  10. Cytotoxic responses and potential respiratory health effects of carbon and carbonaceous nanoparticulates in the Paso del Norte airshed environment.

    PubMed

    Soto, K F; Murr, L E; Garza, K M

    2008-03-01

    We have utilized a range of manufactured or commercial nanoparticulate materials, including surrogate carbon nano-PM along with combustion-generated carbonaceous (soot) nano-PM characteristic of environmental nano- PM (both indoor and outdoor) to investigate and compare their cytotoxic response in vitro with an immortalized human epithelial (lung model) cell line (A549). These have included nano-Ag, Al2O3, TiO2, Fe2O3, ZrO2, Si3N4, chrysotile asbestos, BC, 2 types of MWCNT-aggregate PM (MWCNT-R and MWCNT-N), and high-volume glass fiber collected soots: candle, wood, diesel (truck), tire, and 3-types of natural gas kitchen burner-generated soots: yellow (fuel-rich) flame, low-flow blue flame, and normal flow blue flame soot PM. These carbonaceous nano-PM species can be found in either the indoor and outdoor environments or microenvironments. Two-day and two-week in-vitro cultures of A549 showed cell death (or decreased cell viability) for all nanoparticulate materials, but especially significant for all but the TiO2 and candle, wood, and diesel PM. The natural gas kitchen burner combustion PM cell death response was characteristic of BC and MWCNT PM. There was no correlation with total PAH content of the soot PM. Cytokine release (IL-6, IL-8) was detected for the Ag, Fe2 O3, asbestos, BC and the MWCNT PM. Reactive oxygen species (ROS) production was also detected for Ag, Fe2 O3, ZrO2, asbestos, BC, and the MWCNT aggregate PM, as well as the natural gas kitchen burner combustion PM. TEM, FESEM, and optical microscopy examination of these nanomaterials illustrate the wide range in PM morphologies and crystallinities as well as cell morphologies. Taken together, these results illustrate proinflammatory and related respiratory health issues in relation to environmental nanoparticulates. PMID:18441401

  11. Electroacoustics modeling of piezoelectric welders for ultrasonic additive manufacturing processes

    NASA Astrophysics Data System (ADS)

    Hehr, Adam; Dapino, Marcelo J.

    2016-04-01

    Ultrasonic additive manufacturing (UAM) is a recent 3D metal printing technology which utilizes ultrasonic vibrations from high power piezoelectric transducers to additively weld similar and dissimilar metal foils. CNC machining is used intermittent of welding to create internal channels, embed temperature sensitive components, sensors, and materials, and for net shaping parts. Structural dynamics of the welder and work piece influence the performance of the welder and part quality. To understand the impact of structural dynamics on UAM, a linear time-invariant model is used to relate system shear force and electric current inputs to the system outputs of welder velocity and voltage. Frequency response measurements are combined with in-situ operating measurements of the welder to identify model parameters and to verify model assumptions. The proposed LTI model can enhance process consistency, performance, and guide the development of improved quality monitoring and control strategies.

  12. Modeling Visibility in the EL Paso del Norte Region

    NASA Astrophysics Data System (ADS)

    Fitzgerald, R. M.; Medina, R.; DuBois, D. W.; Novlan, D.

    2013-12-01

    Poor visibility is a subject of growing public concern throughout the U.S, and an active area of research. Its societal impacts in air quality, aviation transport and traffic are significant. Aerosols play a fundamental role in the attenuation of solar radiation, and also affect visibility. The scattering and extinction coefficients of aerosol particles in the Paso del Norte Region have been calculated using the T- matrix model in conjunction with a laser particle counter. Inter-comparison of the model's results of the scattering and absorption coefficients against the corresponding data from a Photoacustic Extinctiometer instrument (which measures in-situ absorption and scattering coefficients of aerosol particles) shows excellent agreement. In addition, the volume-weighted method is used to determine the composite index of refraction which is representative of the aerosols for the Paso del Norte Airshed to obtain information of the type of aerosol particles present in the Airshed. The Single Scattering Albedo has also been retrieved using our methodology to obtain further insight into the type of aerosols present on a given day. Finally, the Koschmieder equation has been used to calculate the visual range or visibility, and was correlated with the PM2.5 and PM10 particle concentration present in the Airshed. Our methodology will allow a better understanding of the size and type of aerosol particles that are most detrimental to the visibility for the Paso del Norte Region.

  13. Receptor model source attributions for Utah’s Salt Lake City airshed and the impacts of wintertime secondary ammonium nitrate and ammonium chloride aerosol.

    EPA Science Inventory

    Communities along Utah’s Wasatch Front are currently developing strategies to reduce daily average PM2.5 levels to below National Ambient Air Quality Standards during wintertime, persistent, multi-day stable atmospheric conditions or cold-air pools. Speciated PM2.5 data from the ...

  14. Adaptation of the South-West Wing of Collegium Chemicum of Adam Mickiewicz University in Poznań for Storage Facilities/ Adaptacja Południowo-Zachodniego Skrzydła Budynku Collegium Chemicum Uam W Poznaniu Na Cele Magazynowe

    NASA Astrophysics Data System (ADS)

    Ścigałło, Jacek

    2015-06-01

    The article refers to the problems of adaptation of Collegium Chemicum facilities belonging to Adam Mickiewicz Uniwersity in Poznań to its storage needs. The subject building is situated in Grunwaldzka Street in Poznań. In the introduction part, the building and its structural solutions are described. The results of the materials research and the measurements of the used reinforcement have been presented. The structure diagnostic analyses were performed basing on measurements and research. The analysis allowed the determination of the limit loads. The results of the performed analysis of the current state turned out to be unsatisfactory, not only in terms of the planned storage load but also in terms of the current load state, as was shown by the construction analysis. W pracy przedstawiono problemy związane z adaptacją budynku dydaktycznego Collegium Chemicum przy ul. Grunwaldzkiej w Poznaniu na cele magazynowe Biblioteki Głównej UAM. Na wstępie opisano badany budynek oraz scharakteryzowano zastosowane w nim rozwiązania konstrukcyjne. Przedstawiono wyniki wykonanych badań materiałowych oraz pomiarów inwentaryzacyjnych zastosowanego zbrojenia. Na podstawie wykonanych pomiarów i badań przeprowadzono analizę diagnostyczną konstrukcji, która pozwoliła na wyznaczenie dopuszczalnych wartości obciążeń powierzchni stropowych. Wyniki wykonanej analizy konstrukcji w stanie istniejącym okazały się dalece niezadowalające nie tylko z punktu widzenia planowanych, znacznych obciążeń magazynowych. Analiza wykazała bowiem, że konstrukcja jest już znacznie przeciążona w aktualnym stanie jej obciążenia

  15. Particulate matter formation in the San Joaquin Valley: Modeling of a winter episode

    SciTech Connect

    Kaduwela, A.P.; Hughes, V.M.; Hackney, R.J.; Jackson, B.J.; Magliano, K.L.; Ranzieri, A.J.

    1998-12-31

    The gaseous and particulate matter concentrations in the San Joaquin Valley simulated using UAM-AERO for the January 4--6, 1996 winter episode are presented and compared with the measurements made during this period. The emphasis here is on the formation of secondary aerosols. The sensitivity of modeled results to input data such as initial/boundary conditions, emissions, and meteorological conditions is also described.

  16. Modeling aerosol processes at the local scale

    SciTech Connect

    Lazaridis, M.; Isukapalli, S.S.; Georgopoulos, P.G.

    1998-12-31

    This work presents an approach for modeling photochemical gaseous and aerosol phase processes in subgrid plumes from major localized (e.g. point) sources (plume-in-grid modeling), thus improving the ability to quantify the relationship between emission source activity and ambient air quality. This approach employs the Reactive Plume Model (RPM-AERO) which extends the regulatory model RPM-IV by incorporating aerosol processes and heterogeneous chemistry. The physics and chemistry of elemental carbon, organic carbon, sulfate, sodium, chloride and crustal material of aerosols are treated and attributed to the PM size distribution. A modified version of the Carbon Bond IV chemical mechanism is included to model the formation of organic aerosol, and the inorganic multicomponent atmospheric aerosol equilibrium model, SEQUILIB is used for calculating the amounts of inorganic species in particulate matter. Aerosol dynamics modeled include mechanisms of nucleation, condensation and gas/particle partitioning of organic matter. An integrated trajectory-in-grid modeling system, UAM/RPM-AERO, is under continuing development for extracting boundary and initial conditions from the mesoscale photochemical/aerosol model UAM-AERO. The RPM-AERO is applied here to case studies involving emissions from point sources to study sulfate particle formation in plumes. Model calculations show that homogeneous nucleation is an efficient process for new particle formation in plumes, in agreement with previous field studies and theoretical predictions.

  17. Mesoscale modeling of combined aerosol and photo-oxidant processes in the Eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Lazaridis, M.; Spyridaki, A.; Solberg, S.; Smolík, J.; Zdímal, V.; Eleftheriadis, K.; Aleksanropoulou, V.; Hov, O.; Georgopoulos, P. G.

    2005-03-01

    Particulate matter and photo-oxidant processes in the Eastern Mediterranean have been studied using the UAM-AERO mesoscale air quality model in conjunction with the NILU-CTM regional model. Meteorological data were obtained from the RAMS prognostic meteorological model. The modeling domain includes the eastern Mediterranean area between the Greek mainland and the island of Crete. The modeling system is applied to study the atmospheric processes in three periods, i.e. 13-16 July 2000, 26-30 July 2000 and 7-14 January 2001. The spatial and temporal distributions of both gaseous and particulate matter pollutants have been extensively studied together with the identification of major emission sources in the area. The modeling results were compared with field data obtained in the same period. The objective of the current modeling work was mainly to apply the UAM-AERO mesoscale model in the eastern Mediterranean in order to assess the performed field campaigns and determine that the applied mesoscale model is fit for this purpose. Comparison of the modeling results with measured data was performed for a number of gaseous and aerosol species. The UAM-AERO model underestimates the PM10 measured concentrations during summer and winter campaigns. Discrepancies between modeled and measured data are attributed to unresolved particulate matter emissions. Particulate matter in the area is mainly composed by sulphate, sea salt and crustal materials, and with significant amounts of nitrate, ammonium and organics. During winter the particulate matter and oxidant concentrations were lower than the summer values.

  18. Final Technical Report: Development of the DUSTRAN GIS-Based Complex Terrain Model for Atmospheric Dust Dispersion

    SciTech Connect

    Allwine, K Jerry; Rutz, Frederick C.; Shaw, William J.; Rishel, Jeremy P.; Fritz, Brad G.; Chapman, Elaine G.; Hoopes, Bonnie L.; Seiple, Timothy E.

    2007-05-01

    Activities at U.S. Department of Defense (DoD) training and testing ranges can be sources of dust in local and regional airsheds governed by air-quality regulations. The U.S. Department of Energy’s Pacific Northwest National Laboratory just completed a multi-year project to develop a fully tested and documented atmospheric dispersion modeling system (DUST TRANsport or DUSTRAN) to assist the DoD in addressing particulate air-quality issues at military training and testing ranges.

  19. Use of an inverse method to resolve the temporal and spatial distribution of anthropogenic and biogenic emissions in Atlanta, Georgia

    SciTech Connect

    Chang, M.E.; Hartley, D.; Cardelino, C.; Chang, W.L.

    1996-12-31

    The Urban Airshed Model (UAM) has been used by the State of Georgia in an attempt to demonstrate attainment of the ozone standard for Atlanta. A recent comparison of UAM data to ambient data collected during the 1992 Southern Oxidants Study Atlanta intensive revealed that the model accurately predicts ozone concentrations, but is poorly simulates the concurrent ozone precursors. There were discrepancies in both the anthropogenic and biogenic precursors. For anthropogenic emissions, the ambient ratios of anthropogenic hydrocarbons (AHC) to oxides of nitrogen (NO{sub x}), AHC/NO{sub x}, and carbon monoxide (CO) to NO{sub x}, CO/NO{sub x}, were higher than the emission ratios by 20% and 73% respectively. In this study, the authors use an inverse method to reconcile the differences between the observed and predicted concentrations of ozone precursors. Inverse methods have been successfully applied to many fields including medical imaging, missile guidance, and underground tomography. This study is the first to apply the inverse method to estimate the emissions of the relatively short-lived species important to urban oxidants formation.

  20. Mesoscale modeling of combined aerosol and photo-oxidant processes in the eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Lazaridis, M.; Spyridaki, A.; Solberg, S.; Smolík, J.; Ždímal, V.; Eleftheriadis, K.; Aleksandropoulou, V.; Hov, O.; Georgopoulos, P. G.

    2004-09-01

    Particulate matter and photo-oxidant processes in the Eastern Mediterranean have been studied using the UAM-AERO mesoscale air quality model in conjunction with the NILU-CTM regional model. Meteorological data were obtained from the RAMS prognostic meteorological model. The modeling domain includes the eastern Mediterranean area between the Greek mainland and the island of Crete. The modeling system is applied to study the atmospheric processes in three periods, i.e. 13-16 July 2000, 26-30 July 2000 and 7-14 January 2001. The spatial and temporal distributions of both gaseous and particulate matter pollutants have been extensively studied together with the identification of major emission sources in the area. The modeling results were compared with field data obtained in the same period. Comparison of the modeling results with measured data was performed for a number of gaseous and aerosol species. The UAM-AERO model underestimates the PM10 measured concentrations during summer but better comparison has been obtained for the winter data.

  1. Component based modelling of piezoelectric ultrasonic actuators for machining applications

    NASA Astrophysics Data System (ADS)

    Saleem, A.; Salah, M.; Ahmed, N.; Silberschmidt, V. V.

    2013-07-01

    Ultrasonically Assisted Machining (UAM) is an emerging technology that has been utilized to improve the surface finishing in machining processes such as turning, milling, and drilling. In this context, piezoelectric ultrasonic transducers are being used to vibrate the cutting tip while machining at predetermined amplitude and frequency. However, modelling and simulation of these transducers is a tedious and difficult task. This is due to the inherent nonlinearities associated with smart materials. Therefore, this paper presents a component-based model of ultrasonic transducers that mimics the nonlinear behaviour of such a system. The system is decomposed into components, a mathematical model of each component is created, and the whole system model is accomplished by aggregating the basic components' model. System parameters are identified using Finite Element technique which then has been used to simulate the system in Matlab/SIMULINK. Various operation conditions are tested and performed to demonstrate the system performance.

  2. Chance-constrained/stochastic linear programming model for acid rain abatement—II. Limited colinearity

    NASA Astrophysics Data System (ADS)

    Ellis, J. H.; McBean, E. A.; Farquhar, G. J.

    In Part I of this work, a deterministic model for development of acid rain abatement strategies was extended to a stochastic form through the incorporation of uncertainty in the transfer coefficients which describe long-range pollutant transport and transformation. The two extreme cases of: (i) complete dependence between transfer coefficients (i.e. colinearity); (ii) complete independence (noncolinearity) were developed. In this work, a more realistic 'middle ground' between these two extremes is investigated. This approach and its associated transfer coefficient covariance structure involve limited colinearity. A simplified linear version of the limited colinearity optimization model is employed. An application is presented which shows that a central three-state, one-receptor sub-system ('sub-airshed') in eastern North America plays a dominant role with respect to determining overall system performance characteristics. Nonlinear, nonlinearnonseparable and multiobjective extensions of the stochastic model are discussed.

  3. Comparison of Homogeneous and Heterogeneous CFD Fuel Models for Phase I of the IAEA CRP on HTR Uncertainties Benchmark

    SciTech Connect

    Gerhard Strydom; Su-Jong Yoon

    2014-04-01

    Computational Fluid Dynamics (CFD) evaluation of homogeneous and heterogeneous fuel models was performed as part of the Phase I calculations of the International Atomic Energy Agency (IAEA) Coordinate Research Program (CRP) on High Temperature Reactor (HTR) Uncertainties in Modeling (UAM). This study was focused on the nominal localized stand-alone fuel thermal response, as defined in Ex. I-3 and I-4 of the HTR UAM. The aim of the stand-alone thermal unit-cell simulation is to isolate the effect of material and boundary input uncertainties on a very simplified problem, before propagation of these uncertainties are performed in subsequent coupled neutronics/thermal fluids phases on the benchmark. In many of the previous studies for high temperature gas cooled reactors, the volume-averaged homogeneous mixture model of a single fuel compact has been applied. In the homogeneous model, the Tristructural Isotropic (TRISO) fuel particles in the fuel compact were not modeled directly and an effective thermal conductivity was employed for the thermo-physical properties of the fuel compact. On the contrary, in the heterogeneous model, the uranium carbide (UCO), inner and outer pyrolytic carbon (IPyC/OPyC) and silicon carbide (SiC) layers of the TRISO fuel particles are explicitly modeled. The fuel compact is modeled as a heterogeneous mixture of TRISO fuel kernels embedded in H-451 matrix graphite. In this study, a steady-state and transient CFD simulations were performed with both homogeneous and heterogeneous models to compare the thermal characteristics. The nominal values of the input parameters are used for this CFD analysis. In a future study, the effects of input uncertainties in the material properties and boundary parameters will be investigated and reported.

  4. Development of aroCACM/MPMPO 1.0: a model to simulate secondary organic aerosol from aromatic precursors in regional models

    NASA Astrophysics Data System (ADS)

    Dawson, Matthew L.; Xu, Jialu; Griffin, Robert J.; Dabdub, Donald

    2016-06-01

    The atmospheric oxidation of aromatic compounds is an important source of secondary organic aerosol (SOA) in urban areas. The oxidation of aromatics depends strongly on the levels of nitrogen oxides (NOx). However, details of the mechanisms by which oxidation occurs have only recently been elucidated. Xu et al. (2015) developed an updated version of the gas-phase Caltech Atmospheric Chemistry Mechanism (CACM) designed to simulate toluene and m-xylene oxidation in chamber experiments over a range of NOx conditions. The output from such a mechanism can be used in thermodynamic predictions of gas-particle partitioning leading to SOA. The current work reports the development of a model for SOA formation that combines the gas-phase mechanism of Xu et al. (2015) with an updated lumped SOA-partitioning scheme (Model to Predict the Multi-phase Partitioning of Organics, MPMPO) that allows partitioning to multiple aerosol phases and that is designed for use in larger-scale three-dimensional models. The resulting model is termed aroCACM/MPMPO 1.0. The model is integrated into the University of California, Irvine - California Institute of Technology (UCI-CIT) Airshed Model, which simulates the South Coast Air Basin (SoCAB) of California. Simulations using 2012 emissions indicate that "low-NOx" pathways to SOA formation from aromatic oxidation play an important role, even in regions that typically exhibit high-NOx concentrations.

  5. Ionosphere/thermosphere simulations with the Canadian Atmosphere And Ionosphere Model

    NASA Astrophysics Data System (ADS)

    Martynenko, Oleg; Ward, William E.; Shepherd, Gordon; Cho, Young-Min; Fomichev, Victor; Sinem Ince, Elmas; Pagiatakis, Spiros; McWilliams, Kathryn

    2016-07-01

    The Canadian Ionosphere and Atmosphere Model (C-IAM) is a newly developed whole atmosphere model. It consists of two pre-existing first principles models: the extended Canadian Middle Atmosphere (CMAM) and the ionospheric part of the Upper Atmosphere Model (UAM). Two-way coupling is implemented between the neutral atmosphere and ionosphere throughout the model domain (which extends from the surface to the inner magnetosphere). The C-IAM is a self-consistent, whole atmosphere model that is capable of studying both the impact of the lower atmosphere on the thermosphere and the ionosphere and the impact of geomagnetic conditions on the neutral atmosphere. In addition to the first principles modelling blocks, the C-IAM includes additional empirical models (e.g., MSISE) which can be incorporated for specific studies. To reproduce the response to specific space weather events, the real (observed) high-latitudinal electric field distribution can be used as input to the model simulations. Successful applications include simulating the wave number 4 features observed in the nighttime O ionospheric emission at 135.6 nm, modelling the 732 nm O+ daytime emission and retrieving from it the atomic oxygen concentration, and explaining disturbances measured by the GOCE satellite accelerometers over high latitudes during geomagnetically active days. This paper will introduce the model and describe these successes.

  6. Modeling METREX Tracer Releases Using High-Resolution WRF Meteorology

    NASA Astrophysics Data System (ADS)

    Hegarty, J. D.; Draxler, R. R.; Nehrkorn, T.

    2014-12-01

    The Metropolitan Tracer Experiment (METREX) was conducted throughout 1984 over the Washington DC area and consisted of hundreds of passive tracer releases with air samples collected at many downwind locations. The experiment included intensive 4-hour tracer releases conducted once per month starting in April of 1984. We simulate several of these intensive releases that had good air sampling coverage using the HYSPLIT Lagrangian particle dispersion model driven by meteorological fields generated by WRF on grids as fine as 1 km and utilizing an urban canopy model (UCM) to parameterize the bulk impacts of buildings within the DC urban airshed. Results indicate that 1 km meteorology generated with the UCM dramatically improve the dispersion simulation compared to those using coarser meteorological inputs generated without the UCM for the November 8th intensive release. This improvement is due to better representation of the vertical mixing at night in WRF. However, for other cases the impact of resolution and the UCM is not as significant as the dispersion was influenced by other factors. We also investigate the sensitivity of the dispersion calculations to the topographic wind speed correction available in WRF 3.6 and several WRF planetary boundary layer (PBL) parameterizations.

  7. Inclusion in the Workforce for Students with Intellectual Disabilities: A Case Study of a Spanish Postsecondary Education Program

    ERIC Educational Resources Information Center

    Judge, Sharon; Gasset, Dolores Izuzquiza

    2015-01-01

    The Autonomous University of Madrid (UAM) is the first Spanish university to provide training to young people with intellectual disabilities (ID) in the university environment, which qualifies them for inclusion in the workforce. In this practice brief we describe the UAM-Prodis Patronage Chair program, a successful model used at Spanish…

  8. Quantitative comparisons of various air pollutant emission sources of ozone precursors in East Tennessee - a study evaluated from the emission inventory development

    SciTech Connect

    Bandyopadhyay, N.

    1996-12-31

    The United States Department of the Interior has raised concerns regarding air pollution impacts in the Great Smoky Mountains National Park (GSMNP). The formation of the Southern Appalachian Mountains Initiative (SAMI) is regional effort to understand the air quality impacts of emission sources upon the Appalachian Mountains. The Tennessee Division of Air Pollution Control (TDAPC) has recently committed additional resources for the analyses of proposals for increased emissions of air pollutants in East Tennessee. The TDAPC has planned to assess these effects by conducting an air quality modeling project. The United States Environmental Protection Agency`s (US EPA`s) Urban Airshed Model (UAM) has been used as the primary air quality model for this purpose. The purpose of this project will be to evaluate the expected impact of any major new or modified air pollution source located in Tennessee on ozone in the GSMNP. An accurate emission inventory is essential to any air quality modeling analysis. A modeling inventory has been developed by the TDAPC for the base year 1993. The modeling area includes 40 counties in East and Middle Tennessee and 42 counties in neighboring states. For the counties in Tennessee, a detailed inventory of the point sources was prepared. For the other states inside the modeling domain, the EPA`s Aerometric Information Retrieval System (AIRS)-AIRS Facility Subsystem (AFS) was used to obtain point source data, The accuracy of the AFS data for the other states was not addressed, A detailed quantitative analysis has been conducted with the emission inventory developed for Tennessee counties. The purpose of this study is to quantify the relative contributions of the emissions of Volatile Organic Compounds (VOCs) and Nitrogen Oxides (NO{sub x}) from different point, area, mobile and biogenic sources to ozone formation in the vicinity of the GSMNP.

  9. Modeling the convective transport of pollutants from eastern Colorado, USA into Rocky Mountain National Park

    NASA Astrophysics Data System (ADS)

    Pina, A.; Schumacher, R. S.; Denning, S.

    2015-12-01

    Rocky Mountain National Park (RMNP) is a Class I Airshed designated under the Clean Air Act. Atmospheric nitrogen (N) deposition in the Park has been a known problem since weekly measurements of wet deposition of inorganic N began in the 1980s by the National Atmospheric Deposition Program (NADP). The addition of N from urban and agriculture emissions along the Colorado Front Range to montane ecosystems degrades air quality/visibility, water quality, and soil pH levels. Based on NADP data during summers 1994-2014, wet N deposition at Beaver Meadows in RMNP exhibited a bimodal gamma distribution. In this study, we identified meteorological transport mechanisms for 3 high wet-N deposition events (all events were within the secondary peak of the gamma distribution) using the North American Regional Reanalysis (NARR) and the Weather Research and Forecasting (WRF) model. The NARR was used to identify synoptic-scale influences on the transport; the WRF model was used to analyze the convective transport of pollutants from a concentrated animal feeding operation near Greeley, Colorado, USA. The WRF simulation included a passive tracer from the feeding operation and a convection-permitting horizontal spacing of 4/3 km. The three cases suggest (a) synoptic-scale moisture and flow patterns are important for priming summer transport events and (b) convection plays a vital role in the transport of Front Range pollutants into RMNP.

  10. Development of a speciated, hourly, and gridded air pollutants emission modeling system--a case study on the precursors of photochemical smog in the Seoul metropolitan area, Korea.

    PubMed

    Kim, D Y; Kim, J W

    2000-03-01

    A speciated, hourly, and gridded air pollutants emission modeling system (SHEMS) was developed and applied in predicting hourly nitrogen dioxide (NO2) and ozone (O3) levels in the Seoul Metropolitan Area (SMA). The primary goal of the SHEMS was to produce a systemized emission inventory for air pollutants including ozone precursors for modeling air quality in urban areas. The SHEMS is principally composed of three parts: (1) a pre-processor to process emission factors, activity levels, and spatial and temporal information using a geographical information system; (2) an emission model for each source type; and (3) a post-processor to produce report and input data for air quality models through database modeling. The source categories in SHEMS are point, area, mobile, natural, and other sources such as fugitive emissions. The emission database produced by SHEMS contains 22 inventoried compounds: sulfur dioxide, NO2, carbon monoxide, and 19 speciated volatile organic compounds. To validate SHEMS, the emission data were tested with the Urban Airshed Model to predict NO2 and O3 concentrations in the SMA during selected episode days in 1994. The results turned out to be reliable in describing temporal variation and spatial distribution of those pollutants.

  11. A comparative analysis of the model calculated and GPS-observed TEC variations before the Haiti, 2010 and Japan, 2011 earthquakes

    NASA Astrophysics Data System (ADS)

    Namgaladze, Alexander; Karpov, Mikhail; Zolotov, Oleg

    2013-04-01

    Model simulations of the ionosphere Total Electron Content (TEC) variations have been performed for the Haiti January 12, 2010 and Japan March 11, 2011 earthquakes. Calculations have been carried out using the global numerical Upper Atmosphere Model (UAM). The seismogenic impacts in the model have been set as lower boundary conditions for the electric potential equation. Namely, the vertical electric currents of ~ 20 nA/m2 flowing from the ionosphere to the Earth have been set at the near-epicenter area of ~ 250 by 2000 km. The simulated relative (%) TEC disturbances for both events have been compared to each other and to the corresponding GPS-observed data. The common features persisting at both observed and modeled TEC variations are: (1) the appearance of positive disturbances 20 - 40% by magnitude at night hours for 2 - 4 days before the earthquake, (2) the geomagnetic conjugation of the effects and (3) the lack of migration (movements) of the TEC deviations during their lifetime (of ~ 8 hours). Main differences between the considered events (Haiti and Japan), both modeled and observed, are most evidently pronounced in the TEC disturbances' maximum location relative to the geomagnetic equator. In case of the Haiti earthquake the strongest by magnitude TEC disturbances are located near the magnetically conjugated to the earthquake's epicenter region at the Southern hemisphere, while in case of the Japan earthquake - near the epicenter at the Northern hemisphere. We have attributed this difference to the different seasons the events have taken place in. The asymmetry of the Haiti model TEC disturbances relative to the magnetic meridian of the earthquake's epicenter is in agreement with the GPS-observed one. In case of the Japan earthquake the asymmetry of the TEC deviations relative to the magnetic meridian of the earthquake's epicenter is negligible in the observations, while in the model results it is similar to the Haiti case. In order to remove this asymmetry

  12. Bioavailable transition metals in particulate matter mediate cardiopulmonary injury in healthy and compromised animal models.

    PubMed Central

    Costa, D L; Dreher, K L

    1997-01-01

    Many epidemiologic reports associate ambient levels of particulate matter (PM) with human mortality and morbidity, particularly in people with preexisting cardiopulmonary disease (e.g., chronic obstructive pulmonary disease, infection, asthma). Because much ambient PM is derived from combustion sources, we tested the hypothesis that the health effects of PM arise from anthropogenic PM that contains bioavailable transition metals. The PM samples studied derived from three emission sources (two oil and one coal fly ash) and four ambient airsheds (St. Louis, MO; Washington; Dusseldorf, Germany; and Ottawa, Canada). PM was administered to rats by intratracheal instillation in equimass or equimetal doses to address directly the influence of PM mass versus metal content on acute lung injury and inflammation. Our results indicated that the lung dose of bioavailable transition metal, not instilled PM mass, was the primary determinant of the acute inflammatory response for both the combustion source and ambient PM samples. Residual oil fly ash, a combustion PM rich in bioavailable metal, was evaluated in a rat model of cardiopulmonary disease (pulmonary vasculitis/hypertension) to ascertain whether the disease state augmented sensitivity to that PM. Significant mortality and enhanced airway responsiveness were observed. Analysis of the lavaged lung fluids suggested that the milieu of the inflamed lung amplified metal-mediated oxidant chemistry to jeopardize the compromised cardiopulmonary system. We propose that soluble metals from PM mediate the array of PM-associated injuries to the cardiopulmonary system of the healthy and at-risk compromised host. PMID:9400700

  13. Modeling total reduced sulfur and sulfur dioxide emissions from a kraft recovery boiler using an artificial neural network, and, Investigating volatile organic compounds in an urban intermountain valley using a TD/GC/MS methodology and intrinsic tracer molecules

    NASA Astrophysics Data System (ADS)

    Wrobel, Christopher Louis

    2000-11-01

    Back-propagation neural networks were trained to predict total reduced sulfur (TRS) and SO2 emissions from kraft recovery boiler operational data. A 0.721 coefficient of correlation was achieved between actual and predicted sulfur emissions on test data withheld from network training. The artificial neural network (ANN) models found an inverse, linear relationship between TRS/SO2 emissions and percent opacity. A number of relationships among operating parameters and sulfur emissions were identified by the ANN models. These relationships were used to formulate strategies for reducing sulfur emissions. Disagreement between ANN model predictions on a subsequent data set revealed an additional scenario for sulfur release not present in the training data. ANN modeling was demonstrated to be an effective tool for analyzing process variables when balancing productivity and environmental concerns. Five receptor sites distributed in the Missoula Valley, Montana, were employed to investigate possible VOC (benzene, 2,3,4-trimethylpentane, toluene, ethylbenzene, m-/p-xylene, o-xylene, naphthalene, acetone, chloroform, α-pinene, β-pinene, p-cymene and limonene) sources. The most dominant source of VOCs was found to be vehicle emissions. Furthermore, anthropogenic sources of terpenoids overwhelmed biogenic emissions, on a local scale. Difficulties correlating wind direction and pollutant levels could be explained by wind direction variability, low wind speed and seasonally dependent meteorological factors. Significant evidence was compiled to support the use of p-cymene as a tracer molecule for pulp mill VOC emissions. Apportionment techniques using o-xylene and p-cymene as tracers for automobile and pulp mill emissions, respectively, were employed to estimate each source's VOC contribution. Motor vehicles were estimated to contribute between 56 and 100 percent of the aromatic pollutants in the Missoula Valley airshed, depending upon the sampling location. Pulp mill emissions

  14. Remote sensing and hydrological modeling of burn scars

    NASA Astrophysics Data System (ADS)

    Miller, Mary Ellen

    This study examined the potential usefulness of combining remote sensing data with hydrologic models and mapping tools available from Geographic Information Systems (GIS), to evaluate the effects of wildfire. Four subprojects addressed this issue: (1) validation of burn scar maps derived from the Advanced Very High Resolution Radiometer (AVHRR) with the National Fire Occurrence Database; (2) testing the potential of thermal MODIS (Moderate Resolution Imaging Spectroradiometer) data for near-real time burn scar and fire severity mapping; (3) evaluation of Landsat derived burn severity maps within WEPP through the Geo-spatial interface for the Water Erosion Prediction Project (GeoWEPP), and (4) predicting potential post-fire erosion for western U.S. forests utilizing existing datasets and models. Wildfire poses incredibly complex management problems in all of its stages. Today's land managers have the option of trying to mitigate the effects of a severe fire before it occurs by fuel management practices. This process is expensive especially considering the uncertainty of when and where the next fire in a given region will occur. When a wildfire does occur, deciding when to let it burn and when to suppress it may lead to controversial decisions. In addition to the threat to life and property from the fire itself, smoke emissions from large fires can cause air quality problems in distant airsheds. Even after the fire is extinguished, erosion and water quality problems may pose difficult management questions. Contributions stemming from these studies include improved burn scar maps for studying historical fire extent and demonstration of the feasibility of using thermal satellite data to predict burn scar extent when clouds and smoke obscure visible bands. The incorporation of Landsat derived burn severity maps was shown to improve post-fire erosion modeling results. Finally the potential post-fire burn severity and erosion risk maps generated for western US forests

  15. The cold air drainage model KLAM_21

    NASA Astrophysics Data System (ADS)

    Kossmann, M.

    2010-09-01

    A brief description of the physics and numerical techniques of the cold air drainage model KLAM_21 is presented. The model has been developed by the Deutscher Wetterdienst (Sievers, 2005) for simulations of nocturnal airflow in hilly and mountainous terrain under dry fair weather conditions. The model has been widely used as an environmental consultancy tool. Typical model applications include frost protection (cold air ponding) and air quality (nocturnal ventilation). The single-layer model calculates the depth and the mean wind of a surface based stable layer that evolves from a neutrally stratified atmosphere during nighttime. The prediction of the velocity and direction of the cold air drainage is based on vertically averaged momentum tendency equations. Temporal changes in the total heat deficit in the cold air layer are calculated from a prescribed local heat loss rate (describing turbulent and radiative cooling) and advection (donor-cell algorithm). The depth of the cold air layer (depth of the surface based temperature inversion) is calculated diagnostically from the total heat loss deficit. The model is initialised with neutral stratification at sunset (onset time of nocturnal cooling). Optionally, effects of an ambient (regional) wind and/or the dispersion of a passive tracer can be simulated. Integration over time is carried out on a regular Arakawa C grid using dynamically calculated time steps. Spatial gradients are discretised using centred differential quotients. The standard size of the computational domains can reach up to 1500 x 1500 grid cells. Grid resolutions usually range between 10 m and 500 m. High resolution simulation can be limited to a nested inner grid domain, while the courser outer domain is covering the entire airshed of interest. A friendly user interface allows easy setup, control, and evaluation of model simulations. Some selected examples of KLAM_21 applications are shown to illustrate the features and capabilities of the model

  16. The use of wind fields in a land use regression model to predict air pollution concentrations for health exposure studies

    NASA Astrophysics Data System (ADS)

    Arain, M. A.; Blair, R.; Finkelstein, N.; Brook, J. R.; Sahsuvaroglu, T.; Beckerman, B.; Zhang, L.; Jerrett, M.

    A methodology is developed to include wind flow effects in land use regression (LUR) models for predicting nitrogen dioxide (NO 2) concentrations for health exposure studies. NO 2 is widely used in health studies as an indicator of traffic-generated air pollution in urban areas. Incorporation of high-resolution interpolated observed wind direction from a network of 38 weather stations in a LUR model improved NO 2 concentration estimates in densely populated, high traffic and industrial/business areas in Toronto-Hamilton urban airshed (THUA) of Ontario, Canada. These small-area variations in air pollution concentrations that are probably more important for health exposure studies may not be detected by sparse continuous air pollution monitoring network or conventional interpolation methods. Observed wind fields were also compared with wind fields generated by Global Environmental Multiscale-High resolution Model Application Project (GEM-HiMAP) to explore the feasibility of using regional weather forecasting model simulated wind fields in LUR models when observed data are either sparse or not available. While GEM-HiMAP predicted wind fields well at large scales, it was unable to resolve wind flow patterns at smaller scales. These results suggest caution and careful evaluation of regional weather forecasting model simulated wind fields before incorporating into human exposure models for health studies. This study has demonstrated that wind fields may be integrated into the land use regression framework. Such integration has a discernable influence on both the overall model prediction and perhaps more importantly for health effects assessment on the relative spatial distribution of traffic pollution throughout the THUA. Methodology developed in this study may be applied in other large urban areas across the world.

  17. EXPOSURE TO VOLATILE ORGANIC COMPOUNDS MEASURED IN A SOURCE IMPACTED AIRSHED

    EPA Science Inventory

    A three-year exposure monitoring study is being conducted in a large city in the Midwestern U.S. The study is aimed at determining the factors influencing exposures to air pollutants of outdoor origin, including volatile organic compounds (VOCs) and particulate matter.

  18. Inverse Modeling for the anthropogenic emission estimation by 4D-var

    NASA Astrophysics Data System (ADS)

    Paschalidi, Zoi; Elbern, Hendrik; Friese, Elmar; Kasradze, Ketevan

    2014-05-01

    A key to better understanding the complex atmospheric processes is the quantitative determination of the emission patterns. Emissions of urban areas contribute to influence greater areas than the actual city area. These influences can be local (air-pollution, heat islands), regional (air-pollution, precipitation) or potentially global (long range transport and vertical transport into the UTLS levels). That is why our study deals with the estimations of the anthropogenic emission strength and the chemical evolution of urban air-sheds, using the techniques of Inverse Modeling. The chemical four-dimensional data assimilation system that is applied within the European Air Pollution and Dispersion chemistry-transport model and its inverse modeling module (EURAD-IM), is already generalized by including not only chemical state estimates, but also emission rate optimization. This achievement follows the objectives of data assimilation and provides an accurate and consistent image of the atmosphere. In the present work an extension of this state is done for a better estimation of the emission factors. A novel approach has been produced, which gives the best estimation of the multivariate covariance matrices of the optimization problem. This is done by updating the emission factor error covariance matrix to 24 emitted species, as well as by adapting the adjoint code to the new online emission model by TNO. Joint optimization of the initial values of the chemical constituents and the emission rates takes place in the study of two special episodes in North Rhine-Westphalia (NRW) region in Germany: an ozone episode in July 2010 and an aerosol episode during the winter of 2012. The nesting techniques that are applied go from 15 km resolution, for the European domain, down to 5 km resolution for Central Europe, and is scheduled to end with 1 km resolution for NRW, implying an indispensable knowledge of the emission patterns. For the assimilation, different kind of observational

  19. An investigation into using the CALMET/CALPUFF modeling system for assessing atmospheric nitrogen deposition in the Chesapeake Bay

    SciTech Connect

    Sherwell, J.; Garrison, M.

    1997-12-31

    The Maryland Department of Natural Resources Power Plant Research Program (PPRP) has a long-standing interest in the water quality of the Chesapeake Bay. A plan has been developed for the ten tributary regions in Maryland that feed into the Chesapeake Bay. Possible reductions in NO{sub x} deposition rates achievable from reductions in airborne NO{sub x} due to Clean Air Act mandates for power plants are of interest in helping to meet the nutrient reduction targets. The Regional Acid Deposition Model (RADM) has been used to estimate NO{sub x} deposition quantities and the extent of the airshed for the Chesapeake Bay. The CALMET/CALPUFF modeling system, recently made available to the public via EPA`s Technology Transfer Network (TTN), is a meteorological and concentration/deposition modeling system that offers a great deal of flexibility for modeling airborne NO{sub x} deposition and for possibly complementing the RADM analyses. A study by PPRP is underway to explore different ways in which the CALMET/CALPUFF modeling system can provide insights into magnitudes, sources, and possible reductions of NO{sub x} deposition to the Bay. The Penn State/NCAR Mesoscale Model (MM4) gridded data set for 1990 has been used for meteorological inputs, and EPA`s 1990 National Emissions Inventory for NO{sub x} has been used to derive source inputs. The CALPUFF analysis is being conducted to provide information in three primary areas: first, detailed deposition estimates for the northern part of the Chesapeake Bay around Baltimore; second, source or source group-specific estimates of deposition in the receptor region for both local and distant sources; and third, time series of deposition patterns throughout the receptor region. This paper reports on the experiences gained in preparing and running the CALMET/CALPUFF system, and on the preliminary results of the analysis of NO{sub x} deposition to the Chesapeake Bay.

  20. Modeling smog chamber measurements of incremental reactivities of volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Chang, T. Y.; Nance, B. I.; Kelly, N. A.

    A series of experiments performed at the GM chamber facility provided useful data for the evaluation of two current chemical mechanisms used in airshed models (SAPRC97 and SAPRC93 mechanisms) and a test of their predictions of maximum incremental reactivities which describe the change in ozone caused by adding a small amount of a compound to a polluted urban mixture under high-NO x conditions. In general, the SAPRC97 detailed mechanism performed well in simulating the volatile organic compound (VOC) reactivity experiments for most test species; however, it had a tendency to underpredict incremental reactivities. For base-case runs containing a nine-component urban-surrogate mixture under high-NO x conditions, where maximum concentrations of either O 3 or the smog produced (SP=the initial NO oxidized plus the ozone produced) were not attained during a 12-h irradiation, the SAPRC97 performed well while the SAPRC93 underestimated SP or O 3 significantly. Under low-NO x conditions where SP or O 3 maximums were attained, the SAPRC97 as well as the SAPRC93 underpredicted SP or O 3 for runs containing the urban-surrogate mixture. Simulations of incremental reactivity experiments and special chamber runs showed that the SAPRC97 mechanism performed poorly for n-octane and some aromatic isomers such as ethylbenzene and p-xylene, while it performed well for other aromatic isomers such as toluene, m-xylene and 1,3,5-trimethylbenzene. Although, additional chamber data for aromatic isomers is needed to further clarify the parameterized chemical mechanisms for aromatic isomers, the newer SAPRC97 mechanism appears to be much improved over the older SAPRC93 mechanism for simulating aromatic chemistry.

  1. Characterization of Steel-Ta Dissimilar Metal Builds Made Using Very High Power Ultrasonic Additive Manufacturing (VHP-UAM)

    NASA Astrophysics Data System (ADS)

    Sridharan, Niyanth; Norfolk, Mark; Babu, Sudarsanam Suresh

    2016-05-01

    Ultrasonic additive manufacturing is a solid-state additive manufacturing technique that utilizes ultrasonic vibrations to bond metal tapes into near net-shaped components. The major advantage of this process is the ability to manufacture layered structures with dissimilar materials without any intermetallic formation. Majority of the published literature had focused only on the bond formation mechanism in Aluminum alloys. The current work pertains to explain the microstructure evolution during dissimilar joining of iron and tantalum using very high power ultrasonic additive manufacturing and characterization of the interfaces using electron back-scattered diffraction and Nano-indentation measurement. The results showed extensive grain refinement at the bonded interfaces of these metals. This phenomenon was attributed to continuous dynamic recrystallization process driven by the high strain rate plastic deformation and associated adiabatic heating that is well below 50 pct of melting point of both iron and Ta.

  2. Modeling

    SciTech Connect

    Loth, E.; Tryggvason, G.; Tsuji, Y.; Elghobashi, S. E.; Crowe, Clayton T.; Berlemont, A.; Reeks, M.; Simonin, O.; Frank, Th; Onishi, Yasuo; Van Wachem, B.

    2005-09-01

    Slurry flows occur in many circumstances, including chemical manufacturing processes, pipeline transfer of coal, sand, and minerals; mud flows; and disposal of dredged materials. In this section we discuss slurry flow applications related to radioactive waste management. The Hanford tank waste solids and interstitial liquids will be mixed to form a slurry so it can be pumped out for retrieval and treatment. The waste is very complex chemically and physically. The ARIEL code is used to model the chemical interactions and fluid dynamics of the waste.

  3. Winter season air pollution in El Paso-Ciudad Juarez. A review of air pollution studies in an international airshed

    SciTech Connect

    Einfeld, W.; Church, H.W.

    1995-03-01

    This report summarizes a number of research efforts completed over the past 20 years in the El Paso del Norte region to characterize pollution sources and air quality trends. The El Paso del Norte region encompasses the cities of El Paso, Texas and Ciudad Juarez, Chihuahua and is representative of many US-Mexico border communities that are facing important air quality issues as population growth and industrialization of Mexican border communities continue. Special attention is given to a group of studies carried out under special US Congressional funding and administered by the US Environmental Protection Agency. Many of these studies were fielded within the last several years to develop a better understanding of air pollution sources and trends in this typical border community. Summary findings from a wide range of studies dealing with such issues as the temporal and spatial distribution of pollutants and pollution potential from both stationary and mobile sources in both cities are presented. Particular emphasis is given to a recent study in El Paso-Ciudad Juarez that focussed on winter season PM{sub 10} pollution in El Paso-Ciudad Juarez. Preliminary estimates from this short-term study reveal that biomass combustion products and crustal material are significant components of winter season PM{sub 10} in this international border community.

  4. STUDYING THE EFFECTS OF AEROSOLS ON VERTICAL PHOTOLYSIS RATE COEFFICIENT AND TEMPERATURE PROFILES OVER AN URBAN AIRSHED (R823186)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  5. Characterization of primary and secondary organic aerosols in Melbourne airshed: The influence of biogenic emissions, wood smoke and bushfires

    NASA Astrophysics Data System (ADS)

    Iinuma, Yoshiteru; Keywood, Melita; Herrmann, Hartmut

    2016-04-01

    Detailed chemical characterisation was performed for wintertime and summertime PM10 samples collected in Melbourne, Australia. The samples were analysed for marker compounds of biomass burning and biogenic secondary organic aerosol (SOA). The chemical analysis showed that the site was significantly influenced by the emissions from wintertime domestic wood combustion and summertime bushfires. Monosaccharide anhydrides were major primary biomass burning marker compounds found in the samples with the average concentrations of 439, 191, 57 and 3630 ngm-3 for winter 2004, winter 2005, summer 2005 and summer 2006, respectively. The highest concentration was determined during the summer 2006 bushfire season with the concentration of 15,400 ngm-3. Biomass burning originating SOA compounds detected in the samples include substituted nitrophenols, mainly 4-nitrocatechol (Mr 155), methyl-nitrocatechols (Mr 169) and dimethyl-nitrocatechols (Mr 183) with the sum concentrations as high as 115 ngm-3 for the wintertime samples and 770 ngm-3 for the bushfire influenced samples. In addition to this, elevated levels of biogenic SOA marker compounds were determined in the summertime samples influence by bushfire smoke. These marker compounds can be categorised into carboxylic acid marker compounds and heteroatomic organic acids containing nitrogen and sulfur. Carboxylic acid marker compounds can be largely attributed to oxidation products originating from 1,8-cineole, α-pinene and β-pinene that are main constituents of eucalyptus VOC emissions. Among those, diaterpenylic acid, terpenylic acid and daterebic acid were found at elevated levels in the bushfire influenced samples. Heteroatomic monoterpene SOA marker compounds (Mr 295, C10H17NO7S) were detected during both winter and summer periods. Especially high levels of these compounds were determined in the severe bushfire samples from summer 2006. Based on the results obtained from the chemical analysis and a macro tracer method, we estimated that 1,8-cineole SOA alone contributed up to 3.5% of secondary organic carbon mass during the bushfire period in 2006. It is likely that biogenic VOC oxidation can be an important source of biomass burning organic aerosol mass.

  6. SURVEY OF VOLATILE ORGANIC COMPOUNDS ASSOCIATED WITH AUTOMOTIVE EMISSIONS IN THE URBAN AIRSHED OF SAO PAULO, BRAZIL

    EPA Science Inventory

    The Metropolitan Region of Sao Paulo (MRSP), Brazil, is one of the largest metropolitan areas in the world (population 17 million, approx.) and relies heavily on alcohol-based fuels for automobiles. It is estimated that about 40% of the total volume of fuel is ethanol with som...

  7. Optimal welding parameters for very high power ultrasonic additive manufacturing of smart structures with aluminum 6061 matrix

    NASA Astrophysics Data System (ADS)

    Wolcott, Paul J.; Hehr, Adam; Dapino, Marcelo J.

    2014-03-01

    Ultrasonic additive manufacturing (UAM) is a recent solid state manufacturing process that combines ad- ditive joining of thin metal tapes with subtractive milling operations to generate near net shape metallic parts. Due to the minimal heating during the process, UAM is a proven method of embedding Ni-Ti, Fe-Ga, and PVDF to create active metal matrix composites. Recently, advances in the UAM process utilizing 9 kW very high power (VHP) welding has improved bonding properties, enabling joining of high strength materials previously unweldable with 1 kW low power UAM. Consequently, a design of experiments study was conducted to optimize welding conditions for aluminum 6061 components. This understanding is critical in the design of UAM parts containing smart materials. Build parameters, including weld force, weld speed, amplitude, and temperature were varied based on a Taguchi experimental design matrix and tested for me- chanical strength. Optimal weld parameters were identi ed with statistical methods including a generalized linear model for analysis of variance (ANOVA), mean e ects plots, and interaction e ects plots.

  8. IAEA CRP on HTGR Uncertainty Analysis: Benchmark Definition and Test Cases

    SciTech Connect

    Gerhard Strydom; Frederik Reitsma; Hans Gougar; Bismark Tyobeka; Kostadin Ivanov

    2012-11-01

    Uncertainty and sensitivity studies are essential elements of the reactor simulation code verification and validation process. Although several international uncertainty quantification activities have been launched in recent years in the LWR, BWR and VVER domains (e.g. the OECD/NEA BEMUSE program [1], from which the current OECD/NEA LWR Uncertainty Analysis in Modelling (UAM) benchmark [2] effort was derived), the systematic propagation of uncertainties in cross-section, manufacturing and model parameters for High Temperature Reactor (HTGR) designs has not been attempted yet. This paper summarises the scope, objectives and exercise definitions of the IAEA Coordinated Research Project (CRP) on HTGR UAM [3]. Note that no results will be included here, as the HTGR UAM benchmark was only launched formally in April 2012, and the specification is currently still under development.

  9. A Detailed Process Based Evaluation of Photochemical Air Quality Model Simulations of Houston, TX

    NASA Astrophysics Data System (ADS)

    Vizuete, W.; Kioumourtzoglou, M.; Jeffries, H.

    2006-12-01

    This work will present a process based evaluation of several modeling attempts of the Houston, TX non- attainment area. These modeling attempts include efforts by the Texas state agency, private consultants, and several Universities, resulting in multiple simulations of the same modeling episode and domain. These simulations were performed with the Comprehensive Air quality Model with extensions (CAMx) under a variety of meteorological and emission inputs. Through an initial comparison of model and ambient data the model underpredicts ozone concentrations in nearly every modeling attempt. This observation held true even when a large artificial imputation of ozone precursors, specifically ethylene and propylene, were added to some modeling simulations. An examination of the level of agreement between model predictions and observations of ozone concentrations, however, is not a sufficient method to understand the reasons for this inaccuracy. This is especially true in a non-linear feedback system such as ozone formation where the same ozone prediction can be reached through the combination of various physical and chemical processess. A more meaningful method of model analysis that focuses on theses processes lead to the development of the pyPA (Process Analysis in python) tool. This tool provides a framework for an in-depth analysis of modeling data by quantifying radical budgets, source and fate of ozone precursors, and the physical processes that effect each species. The pyPA tool was used to analyze each simulation scenario of the Houston airshed allowing for a process based intercomparison. An analysis of the radical budget revealed a deficient source of organically derived free radicals (HO2 and OH.) in the modeling system. Atmospheric reactivity and consequently ozone formation was limited by lack of radical sources; regardless of the levels of ethylene or propylene introduced into the system. NOx overpredictions by a factor of two further depleted the limited

  10. Mechanical and Thermal Characterization of Ultrasonic Additive Manufacturing

    NASA Astrophysics Data System (ADS)

    Foster, Daniel R.

    Additive manufacturing is an emerging production technology used to create net shaped 3-D objects from a digital model. Ultrasonic Additive Manufacturing (UAM) is a relatively new type of additive manufacturing that uses ultrasonic energy to sequentially bond layers of metal foils at temperatures much lower than the melting temperature of the material. Constructing metal structures without melting allows UAM to have distinct advantages over beam based additive manufacturing and other traditional manufacturing processes. This is because solidification defects can be avoided, structures can be composed of dissimilar material and secondary materials (both metallic and non-metallic) can be successfully embedded into the metal matrix. These advantages allow UAM to have tremendous potential to create metal matrix composite structures that cannot be built using any other manufacturing technique. Although UAM has tremendous engineering potential, the effect of interfacial bonding defects on the mechanical and thermal properties have not be characterized. Incomplete interfacial bonding at the laminar surfaces due to insufficient welding energy can result in interfacial voids. Voids create discontinuities in the structure which change the mechanical and thermal properties of the component, resulting in a structure that has different properties than the monolithic material used to create it. In-situ thermal experiments and thermal modeling demonstrates that voids at partially bonded interfaces significantly affected heat generation and thermal conductivity in. UAM parts during consolidation as well as in the final components. Using ultrasonic testing, elastic properties of UAM structures were found to be significantly reduced due to the presence of voids, with the reduction being the most severe in the transverse (foil staking) direction. Elastic constants in all three material directions decreased linearly with a reduction in the interfacial bonded area. The linear trend

  11. Validation of the emission inventory in the Sao Paulo Metropolitan Area of Brazil, based on ambient concentrations ratios of CO, NMOG and NO x and on a photochemical model

    NASA Astrophysics Data System (ADS)

    Vivanco, Marta G.; Andrade, Maria de Fátima

    than the official, emission inventories are used, ozone and NO concentrations predicted by the California Institute of Technology (CIT) airshed model more closely match observed values.

  12. Uncertainty characterization and quantification in air pollution models. Application to the CHIMERE model

    NASA Astrophysics Data System (ADS)

    Debry, Edouard; Mallet, Vivien; Garaud, Damien; Malherbe, Laure; Bessagnet, Bertrand; Rouïl, Laurence

    2010-05-01

    probability density function (PDF) is associated with an input parameter, according to its assumed uncertainty. Then the combined PDFs are propagated into the model, by means of several simulations with randomly perturbed input parameters. One may then obtain an approximation of the PDF of modeled concentrations, provided the Monte Carlo process has reasonably converged. The uncertainty analysis with CHIMERE has been led with a Monte Carlo method on the French domain and on two periods : 13 days during January 2009, with a focus on particles, and 28 days during August 2009, with a focus on ozone. The results show that for the summer period and 500 simulations, the time and space averaged standard deviation for ozone is 16 µg/m3, to be compared with an averaged concentration of 89 µg/m3. It is noteworthy that the space averaged standard deviation for ozone is relatively constant over time (the standard deviation of the timeseries itself is 1.6 µg/m3). The space variation of the ozone standard deviation seems to indicate that emissions have a significant impact, followed by western boundary conditions. Monte Carlo simulations are then post-processed by both ensemble [4] and Bayesian [5] methods in order to assess the quality of the uncertainty estimation. (1) Rao, K.S. Uncertainty Analysis in Atmospheric Dispersion Modeling, Pure and Applied Geophysics, 2005, 162, 1893-1917. (2) Beekmann, M. and Derognat, C. Monte Carlo uncertainty analysis of a regional-scale transport chemistry model constrained by measurements from the Atmospheric Pollution Over the Paris Area (ESQUIF) campaign, Journal of Geophysical Research, 2003, 108, 8559-8576. (3) Hanna, S.R. and Lu, Z. and Frey, H.C. and Wheeler, N. and Vukovich, J. and Arunachalam, S. and Fernau, M. and Hansen, D.A. Uncertainties in predicted ozone concentrations due to input uncertainties for the UAM-V photochemical grid model applied to the July 1995 OTAG domain, Atmospheric Environment, 2001, 35, 891-903. (4) Mallet, V., and B

  13. Contribution of upper airway geometry to convective mixing.

    PubMed

    Jayaraju, Santhosh T; Paiva, Manuel; Brouns, Mark; Lacor, Chris; Verbanck, Sylvia

    2008-12-01

    We investigated the axial dispersive effect of the upper airway structure (comprising mouth cavity, oropharynx, and trachea) on a traversing aerosol bolus. This was done by means of aerosol bolus experiments on a hollow cast of a realistic upper airway model (UAM) and three-dimensional computational fluid dynamics (CFD) simulations in the same UAM geometry. The experiments showed that 50-ml boluses injected into the UAM dispersed to boluses with a half-width ranging from 80 to 90 ml at the UAM exit, across both flow rates (250, 500 ml/s) and both flow directions (inspiration, expiration). These experimental results imply that the net half-width induced by the UAM typically was 69 ml. Comparison of experimental bolus traces with a one-dimensional Gaussian-derived analytical solution resulted in an axial dispersion coefficient of 200-250 cm(2)/s, depending on whether the bolus peak and its half-width or the bolus tail needed to be fully accounted for. CFD simulations agreed well with experimental results for inspiratory boluses and were compatible with an axial dispersion of 200 cm(2)/s. However, for expiratory boluses the CFD simulations showed a very tight bolus peak followed by an elongated tail, in sharp contrast to the expiratory bolus experiments. This indicates that CFD methods that are widely used to predict the fate of aerosols in the human upper airway, where flow is transitional, need to be critically assessed, possibly via aerosol bolus simulations. We conclude that, with all its geometric complexity, the upper airway introduces a relatively mild dispersion on a traversing aerosol bolus for normal breathing flow rates in inspiratory and expiratory flow directions.

  14. Contribution of upper airway geometry to convective mixing.

    PubMed

    Jayaraju, Santhosh T; Paiva, Manuel; Brouns, Mark; Lacor, Chris; Verbanck, Sylvia

    2008-12-01

    We investigated the axial dispersive effect of the upper airway structure (comprising mouth cavity, oropharynx, and trachea) on a traversing aerosol bolus. This was done by means of aerosol bolus experiments on a hollow cast of a realistic upper airway model (UAM) and three-dimensional computational fluid dynamics (CFD) simulations in the same UAM geometry. The experiments showed that 50-ml boluses injected into the UAM dispersed to boluses with a half-width ranging from 80 to 90 ml at the UAM exit, across both flow rates (250, 500 ml/s) and both flow directions (inspiration, expiration). These experimental results imply that the net half-width induced by the UAM typically was 69 ml. Comparison of experimental bolus traces with a one-dimensional Gaussian-derived analytical solution resulted in an axial dispersion coefficient of 200-250 cm(2)/s, depending on whether the bolus peak and its half-width or the bolus tail needed to be fully accounted for. CFD simulations agreed well with experimental results for inspiratory boluses and were compatible with an axial dispersion of 200 cm(2)/s. However, for expiratory boluses the CFD simulations showed a very tight bolus peak followed by an elongated tail, in sharp contrast to the expiratory bolus experiments. This indicates that CFD methods that are widely used to predict the fate of aerosols in the human upper airway, where flow is transitional, need to be critically assessed, possibly via aerosol bolus simulations. We conclude that, with all its geometric complexity, the upper airway introduces a relatively mild dispersion on a traversing aerosol bolus for normal breathing flow rates in inspiratory and expiratory flow directions. PMID:18818384

  15. Feasibility study of using the RoboEarth cloud engine for rapid mapping and tracking with small unmanned aerial systems

    NASA Astrophysics Data System (ADS)

    Li-Chee-Ming, J.; Armenakis, C.

    2014-11-01

    This paper presents the ongoing development of a small unmanned aerial mapping system (sUAMS) that in the future will track its trajectory and perform 3D mapping in near-real time. As both mapping and tracking algorithms require powerful computational capabilities and large data storage facilities, we propose to use the RoboEarth Cloud Engine (RCE) to offload heavy computation and store data to secure computing environments in the cloud. While the RCE's capabilities have been demonstrated with terrestrial robots in indoor environments, this paper explores the feasibility of using the RCE in mapping and tracking applications in outdoor environments by small UAMS. The experiments presented in this work assess the data processing strategies and evaluate the attainable tracking and mapping accuracies using the data obtained by the sUAMS. Testing was performed with an Aeryon Scout quadcopter. It flew over York University, up to approximately 40 metres above the ground. The quadcopter was equipped with a single-frequency GPS receiver providing positioning to about 3 meter accuracies, an AHRS (Attitude and Heading Reference System) estimating the attitude to about 3 degrees, and an FPV (First Person Viewing) camera. Video images captured from the onboard camera were processed using VisualSFM and SURE, which are being reformed as an Application-as-a-Service via the RCE. The 3D virtual building model of York University was used as a known environment to georeference the point cloud generated from the sUAMS' sensor data. The estimated position and orientation parameters of the video camera show increases in accuracy when compared to the sUAMS' autopilot solution, derived from the onboard GPS and AHRS. The paper presents the proposed approach and the results, along with their accuracies.

  16. Impact of urbanization and land-use/land-cover change on diurnal temperature range: a case study of tropical urban airshed of India using remote sensing data.

    PubMed

    Mohan, Manju; Kandya, Anurag

    2015-02-15

    Diurnal temperature range (DTR) is an important climate change index. Its knowledge is important to a range of issues and themes in earth sciences central to urban climatology and human-environment interactions. The present study investigates the effect of urbanization on the land surface temperature (LST) based DTR. This study presents spatial and temporal variations of satellite based estimates of annually averaged DTR over megacity Delhi, the capital of India, which are shown for a period of 11 years during 2001-2011 and analyzes this with regard to its land-use/land-cover (LU/LC) changes and population growth. Delhi which witnessed massive urbanization in terms of population growth (decadal growth rate of Delhi during 2001-2011 was 20.96%) and major transformations in the LU/LC (built-up area crossed more than 53%) are experiencing severity in its micro and macroclimate. There was a consistent increase in the areas experiencing DTR below 11°C which typically resembled the 'urban class' viz. from 26.4% in the year 2001 to 65.3% in the year 2011 and subsequently the DTR of entire Delhi which was 12.48°C in the year 2001 gradually reduced to 10.34°C in the year 2011, exhibiting a significant decreasing trend. Rapidly urbanizing areas like Rohini, Dwarka, Vasant Kunj, Kaushambi, Khanjhawala Village, IIT, Safdarjung Airport, etc. registered a significant decreasing trend in the DTR. In the background of the converging DTR, which was primarily due to the increase in the minimum temperatures, a grim situation in terms of potentially net increase in the heat-related mortality rate especially for the young children below 15years of age is envisaged for Delhi. Considering the earlier findings that the level of risk of death remained the highest and longest for Delhi, in comparison to megacities like Sao Paulo and London, the study calls for strong and urgent heat island mitigation measures.

  17. Impact of urbanization and land-use/land-cover change on diurnal temperature range: a case study of tropical urban airshed of India using remote sensing data.

    PubMed

    Mohan, Manju; Kandya, Anurag

    2015-02-15

    Diurnal temperature range (DTR) is an important climate change index. Its knowledge is important to a range of issues and themes in earth sciences central to urban climatology and human-environment interactions. The present study investigates the effect of urbanization on the land surface temperature (LST) based DTR. This study presents spatial and temporal variations of satellite based estimates of annually averaged DTR over megacity Delhi, the capital of India, which are shown for a period of 11 years during 2001-2011 and analyzes this with regard to its land-use/land-cover (LU/LC) changes and population growth. Delhi which witnessed massive urbanization in terms of population growth (decadal growth rate of Delhi during 2001-2011 was 20.96%) and major transformations in the LU/LC (built-up area crossed more than 53%) are experiencing severity in its micro and macroclimate. There was a consistent increase in the areas experiencing DTR below 11°C which typically resembled the 'urban class' viz. from 26.4% in the year 2001 to 65.3% in the year 2011 and subsequently the DTR of entire Delhi which was 12.48°C in the year 2001 gradually reduced to 10.34°C in the year 2011, exhibiting a significant decreasing trend. Rapidly urbanizing areas like Rohini, Dwarka, Vasant Kunj, Kaushambi, Khanjhawala Village, IIT, Safdarjung Airport, etc. registered a significant decreasing trend in the DTR. In the background of the converging DTR, which was primarily due to the increase in the minimum temperatures, a grim situation in terms of potentially net increase in the heat-related mortality rate especially for the young children below 15years of age is envisaged for Delhi. Considering the earlier findings that the level of risk of death remained the highest and longest for Delhi, in comparison to megacities like Sao Paulo and London, the study calls for strong and urgent heat island mitigation measures. PMID:25437763

  18. A new dust transport approach to quantify anthropogenic sources of atmospheric PM10 deposition on lakes

    NASA Astrophysics Data System (ADS)

    Weiss, Lee; Thé, Jesse; Gharabaghi, Bahram; Stainsby, Eleanor A.; Winter, Jennifer G.

    2014-10-01

    Windblown dust simulations are one of the most uncertain types of atmospheric transport models. This study presents an integrated PM10 emission, transport and deposition model which has been validated using monitored data. This model characterizes the atmospheric phosphorus load focusing on the major local sources within the Lake Simcoe airshed including paved and unpaved roads, agricultural sources, construction sites and aggregate mining sources. This new approach substantially reduces uncertainty by providing improved estimates of the friction velocities than those developed previously. Modeling improvements were also made by generating and validating an hourly windfield using detailed meteorology, topography and land use data for the study area. The model was used to estimate dust emissions generated in the airshed and to simulate the long-range transport and deposition of PM10 to Lake Simcoe. The deposition results from the model were verified against observed bulk collector phosphorus concentration data for both wet and dry deposition. Bulk collector data from stations situated outside the airshed in a remote, undeveloped area were also compared to determine the background contribution from distant sources.

  19. Introduction: Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5)

    NASA Astrophysics Data System (ADS)

    Martin, S. T.; Artaxo, P.; Machado, L. A. T.; Manzi, A. O.; Souza, R. A. F.; Schumacher, C.; Wang, J.; Andreae, M. O.; Barbosa, H. M. J.; Fan, J.; Fisch, G.; Goldstein, A. H.; Guenther, A.; Jimenez, J. L.; Pöschl, U.; Silva Dias, M. A.; Smith, J. N.; Wendisch, M.

    2015-11-01

    The Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) Experiment was carried out in the environs of Manaus, Brazil, in the central region of the Amazon basin during two years from 1 January 2014 through 31 December 2015. The experiment focused on the complex interactions among vegetation, atmospheric chemistry, and aerosol production on the one hand and their connections to aerosols, clouds, and precipitation on the other. The objective was to understand and quantify these linked processes, first under natural conditions to obtain a baseline and second when altered by the effects of human activities. To this end, the pollution plume from the Manaus metropolis, superimposed on the background conditions of the central Amazon basin, served as a natural laboratory. The present paper, as the Introduction to the GoAmazon2014/5 Special Issue, presents the context and motivation of the GoAmazon2014/5 Experiment. The nine research sites, including the characteristics and instrumentation of each site, are presented. The sites range from time point zero (T0) upwind of the pollution, to T1 in the midst of the pollution, to T2 just downwind of the pollution, to T3 furthest downwind of the pollution (70 km). In addition to the ground sites, a low-altitude G-159 Gulfstream I (G1) observed the atmospheric boundary layer and low clouds, and a high-altitude Gulfstream G550 (HALO) operated in the free troposphere. During the two-year experiment, two Intensive Operating Periods (IOP1 and IOP2) also took place that included additional specialized research instrumentation at the ground sites as well as flights of the two aircraft. GoAmazon2014/5 IOP1 was carried out from 1 February to 31 March 2014 in the wet season. GoAmazon2014/5 IOP2 was conducted from 15 August to 15 October 2014 in the dry season. The G1 aircraft flew during both IOP1 and IOP2, and the HALO aircraft flew during IOP2. In the context of the Amazon basin, the two IOPs also correspond to the clean

  20. Introduction: Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5)

    NASA Astrophysics Data System (ADS)

    Martin, S. T.; Artaxo, P.; Machado, L. A. T.; Manzi, A. O.; Souza, R. A. F.; Schumacher, C.; Wang, J.; Andreae, M. O.; Barbosa, H. M. J.; Fan, J.; Fisch, G.; Goldstein, A. H.; Guenther, A.; Jimenez, J. L.; Pöschl, U.; Silva Dias, M. A.; Smith, J. N.; Wendisch, M.

    2016-04-01

    The Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) Experiment was carried out in the environs of Manaus, Brazil, in the central region of the Amazon basin for 2 years from 1 January 2014 through 31 December 2015. The experiment focused on the complex interactions among vegetation, atmospheric chemistry, and aerosol production on the one hand and their connections to aerosols, clouds, and precipitation on the other. The objective was to understand and quantify these linked processes, first under natural conditions to obtain a baseline and second when altered by the effects of human activities. To this end, the pollution plume from the Manaus metropolis, superimposed on the background conditions of the central Amazon basin, served as a natural laboratory. The present paper, as the introduction to the special issue of GoAmazon2014/5, presents the context and motivation of the GoAmazon2014/5 Experiment. The nine research sites, including the characteristics and instrumentation of each site, are presented. The sites range from time point zero (T0) upwind of the pollution, to T1 in the midst of the pollution, to T2 just downwind of the pollution, to T3 furthest downwind of the pollution (70 km). In addition to the ground sites, a low-altitude G-159 Gulfstream I (G-1) observed the atmospheric boundary layer and low clouds, and a high-altitude Gulfstream G550 (HALO) operated in the free troposphere. During the 2-year experiment, two Intensive Operating Periods (IOP1 and IOP2) also took place that included additional specialized research instrumentation at the ground sites as well as flights of the two aircraft. GoAmazon2014/5 IOP1 was carried out from 1 February to 31 March 2014 in the wet season. GoAmazon2014/5 IOP2 was conducted from 15 August to 15 October 2014 in the dry season. The G-1 aircraft flew during both IOP1 and IOP2, and the HALO aircraft flew during IOP2. In the context of the Amazon basin, the two IOPs also correspond to the clean and

  1. Introduction: Observations and modeling of the Green Ocean Amazon (GoAmazon2014/5)

    DOE PAGES

    Martin, S. T.; Artaxo, P.; Machado, L. A. T.; Manzi, A. O.; Souza, R. A. F.; Schumacher, C.; Wang, J.; Andreae, M. O.; Barbosa, H. M. J.; Fan, J.; et al

    2016-04-19

    The Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) Experiment was carried out in the environs of Manaus, Brazil, in the central region of the Amazon basin for 2 years from 1 January 2014 through 31 December 2015. The experiment focused on the complex interactions among vegetation, atmospheric chemistry, and aerosol production on the one hand and their connections to aerosols, clouds, and precipitation on the other. The objective was to understand and quantify these linked processes, first under natural conditions to obtain a baseline and second when altered by the effects of human activities. To this end, the pollution plume from themore » Manaus metropolis, superimposed on the background conditions of the central Amazon basin, served as a natural laboratory. The present paper, as the introduction to the special issue of GoAmazon2014/5, presents the context and motivation of the GoAmazon2014/5 Experiment. The nine research sites, including the characteristics and instrumentation of each site, are presented. The sites range from time point zero (T0) upwind of the pollution, to T1 in the midst of the pollution, to T2 just downwind of the pollution, to T3 furthest downwind of the pollution (70 km). In addition to the ground sites, a low-altitude G-159 Gulfstream I (G-1) observed the atmospheric boundary layer and low clouds, and a high-altitude Gulfstream G550 (HALO) operated in the free troposphere. During the 2-year experiment, two Intensive Operating Periods (IOP1 and IOP2) also took place that included additional specialized research instrumentation at the ground sites as well as flights of the two aircraft. GoAmazon2014/5 IOP1 was carried out from 1 February to 31 March 2014 in the wet season. GoAmazon2014/5 IOP2 was conducted from 15 August to 15 October 2014 in the dry season. In addition, the G-1 aircraft flew during both IOP1 and IOP2, and the HALO aircraft flew during IOP2. In the context of the Amazon basin, the two IOPs

  2. Genetic Algorithms and Nucleation in VIH-AIDS transition.

    NASA Astrophysics Data System (ADS)

    Barranon, Armando

    2003-03-01

    VIH to AIDS transition has been modeled via a genetic algorithm that uses boom-boom principle and where population evolution is simulated with a cellular automaton based on SIR model. VIH to AIDS transition is signed by nucleation of infected cells and low probability of infection are obtained for different mutation rates in agreement with clinical results. A power law is obtained with a critical exponent close to the critical exponent of cubic, spherical percolation, colossal magnetic resonance, Ising Model and liquid-gas phase transition in heavy ion collisions. Computations were carried out at UAM-A Supercomputing Lab and author acknowledges financial support from Division of CBI at UAM-A.

  3. Deformation Mechanisms in NiTi-Al Composites Fabricated by Ultrasonic Additive Manufacturing

    NASA Astrophysics Data System (ADS)

    Chen, Xiang; Hehr, Adam; Dapino, Marcelo J.; Anderson, Peter M.

    2015-09-01

    Thermally active NiTi shape memory alloy (SMA) fibers can be used to tune or tailor the effective coefficient of thermal expansion (CTE) of a metallic matrix composite. In this paper, a novel NiTi-Al composite is fabricated using ultrasonic additive manufacturing (UAM). A combined experimental-simulation approach is used to develop and validate a microstructurally based finite element model of the composite. The simulations are able to closely reproduce the macroscopic strain versus temperature cyclic response, including initial transient effects in the first cycle. They also show that the composite CTE is minimized if the austenite texture in the SMA wires is <001>B2, that a fiber aspect ratio >10 maximizes fiber efficiency, and that the UAM process may reduce hysteresis in embedded SMA wires.

  4. Leadership Models.

    ERIC Educational Resources Information Center

    Freeman, Thomas J.

    This paper discusses six different models of organizational structure and leadership, including the scalar chain or pyramid model, the continuum model, the grid model, the linking pin model, the contingency model, and the circle or democratic model. Each model is examined in a separate section that describes the model and its development, lists…

  5. Evaluation of Antibiotics Active against Methicillin-Resistant Staphylococcus aureus Based on Activity in an Established Biofilm.

    PubMed

    Meeker, Daniel G; Beenken, Karen E; Mills, Weston B; Loughran, Allister J; Spencer, Horace J; Lynn, William B; Smeltzer, Mark S

    2016-10-01

    We used in vitro and in vivo models of catheter-associated biofilm formation to compare the relative activity of antibiotics effective against methicillin-resistant Staphylococcus aureus (MRSA) in the specific context of an established biofilm. The results demonstrated that, under in vitro conditions, daptomycin and ceftaroline exhibited comparable activity relative to each other and greater activity than vancomycin, telavancin, oritavancin, dalbavancin, or tigecycline. This was true when assessed using established biofilms formed by the USA300 methicillin-resistant strain LAC and the USA200 methicillin-sensitive strain UAMS-1. Oxacillin exhibited greater activity against UAMS-1 than LAC, as would be expected, since LAC is an MRSA strain. However, the activity of oxacillin was less than that of daptomycin and ceftaroline even against UAMS-1. Among the lipoglycopeptides, telavancin exhibited the greatest overall activity. Specifically, telavancin exhibited greater activity than oritavancin or dalbavancin when tested against biofilms formed by LAC and was the only lipoglycopeptide capable of reducing the number of viable bacteria below the limit of detection. With biofilms formed by UAMS-1, telavancin and dalbavancin exhibited comparable activity relative to each other and greater activity than oritavancin. Importantly, ceftaroline was the only antibiotic that exhibited greater activity than vancomycin when tested in vivo in a murine model of catheter-associated biofilm formation. These results emphasize the need to consider antibiotics other than vancomycin, most notably, ceftaroline, for the treatment of biofilm-associated S. aureus infections, including by the matrix-based antibiotic delivery methods often employed for local antibiotic delivery in the treatment of these infections.

  6. Models and role models.

    PubMed

    ten Cate, Jacob M

    2015-01-01

    Developing experimental models to understand dental caries has been the theme in our research group. Our first, the pH-cycling model, was developed to investigate the chemical reactions in enamel or dentine, which lead to dental caries. It aimed to leverage our understanding of the fluoride mode of action and was also utilized for the formulation of oral care products. In addition, we made use of intra-oral (in situ) models to study other features of the oral environment that drive the de/remineralization balance in individual patients. This model addressed basic questions, such as how enamel and dentine are affected by challenges in the oral cavity, as well as practical issues related to fluoride toothpaste efficacy. The observation that perhaps fluoride is not sufficiently potent to reduce dental caries in the present-day society triggered us to expand our knowledge in the bacterial aetiology of dental caries. For this we developed the Amsterdam Active Attachment biofilm model. Different from studies on planktonic ('single') bacteria, this biofilm model captures bacteria in a habitat similar to dental plaque. With data from the combination of these models, it should be possible to study separate processes which together may lead to dental caries. Also products and novel agents could be evaluated that interfere with either of the processes. Having these separate models in place, a suggestion is made to design computer models to encompass the available information. Models but also role models are of the utmost importance in bringing and guiding research and researchers. PMID:25871413

  7. Models, Fiction, and Fictional Models

    NASA Astrophysics Data System (ADS)

    Liu, Chuang

    2014-03-01

    The following sections are included: * Introduction * Why Most Models in Science Are Not Fictional * Typically Fictional Models in Science * Modeling the Unobservable * Fictional Models for the Unobservable? * References

  8. XerC Contributes to Diverse Forms of Staphylococcus aureus Infection via agr-Dependent and agr-Independent Pathways.

    PubMed

    Atwood, Danielle N; Beenken, Karen E; Loughran, Allister J; Meeker, Daniel G; Lantz, Tamara L; Graham, Justin W; Spencer, Horace J; Smeltzer, Mark S

    2016-04-01

    We demonstrate that mutation of xerC, which reportedly encodes a homologue of an Escherichia coli recombinase, limits biofilm formation in the methicillin-resistant Staphylococcus aureus strain LAC and the methicillin-sensitive strain UAMS-1. This was not due to the decreased production of the polysaccharide intracellular adhesin (PIA) in either strain because the amount of PIA was increased in a UAMS-1xerC mutant and undetectable in both LAC and its isogenic xerC mutant. Mutation of xerC also resulted in the increased production of extracellular proteases and nucleases in both LAC and UAMS-1, and limiting the production of either class of enzymes increased biofilm formation in the isogenic xerC mutants. More importantly, the limited capacity to form a biofilm was correlated with increased antibiotic susceptibility in both strains in the context of an established biofilm in vivo. Mutation of xerC also attenuated virulence in a murine bacteremia model, as assessed on the basis of the bacterial loads in internal organs and overall lethality. It also resulted in the decreased accumulation of alpha toxin and the increased accumulation of protein A. These findings suggest that xerC may impact the functional status of agr. This was confirmed by demonstrating the reduced accumulation of RNAIII and AgrA in LAC and UAMS-1xerC mutants. However, this cannot account for the biofilm-deficient phenotype of xerC mutants because mutation of agr did not limit biofilm formation in either strain. These results demonstrate that xerC contributes to biofilm-associated infections and acute bacteremia and that this is likely due to agr-independent and -dependent pathways, respectively.

  9. Impact of sarA and Phenol-Soluble Modulins on the Pathogenesis of Osteomyelitis in Diverse Clinical Isolates of Staphylococcus aureus.

    PubMed

    Loughran, Allister J; Gaddy, Dana; Beenken, Karen E; Meeker, Daniel G; Morello, Roy; Zhao, Haibo; Byrum, Stephanie D; Tackett, Alan J; Cassat, James E; Smeltzer, Mark S

    2016-09-01

    We used a murine model of acute, posttraumatic osteomyelitis to evaluate the virulence of two divergent Staphylococcus aureus clinical isolates (the USA300 strain LAC and the USA200 strain UAMS-1) and their isogenic sarA mutants. The results confirmed that both strains caused comparable degrees of osteolysis and reactive new bone formation in the acute phase of osteomyelitis. Conditioned medium (CM) from stationary-phase cultures of both strains was cytotoxic to cells of established cell lines (MC3TC-E1 and RAW 264.7 cells), primary murine calvarial osteoblasts, and bone marrow-derived osteoclasts. Both the cytotoxicity of CM and the reactive changes in bone were significantly reduced in the isogenic sarA mutants. These results confirm that sarA is required for the production and/or accumulation of extracellular virulence factors that limit osteoblast and osteoclast viability and that thereby promote bone destruction and reactive bone formation during the acute phase of S. aureus osteomyelitis. Proteomic analysis confirmed the reduced accumulation of multiple extracellular proteins in the LAC and UAMS-1 sarA mutants. Included among these were the alpha class of phenol-soluble modulins (PSMs), which were previously implicated as important determinants of osteoblast cytotoxicity and bone destruction and repair processes in osteomyelitis. Mutation of the corresponding operon reduced the cytotoxicity of CM from both UAMS-1 and LAC cultures for osteoblasts and osteoclasts. It also significantly reduced both reactive bone formation and cortical bone destruction by CM from LAC cultures. However, this was not true for CM from cultures of a UAMS-1 psmα mutant, thereby suggesting the involvement of additional virulence factors in such strains that remain to be identified. PMID:27354444

  10. XerC Contributes to Diverse Forms of Staphylococcus aureus Infection via agr-Dependent and agr-Independent Pathways

    PubMed Central

    Beenken, Karen E.; Loughran, Allister J.; Meeker, Daniel G.; Lantz, Tamara L.; Graham, Justin W.; Spencer, Horace J.

    2016-01-01

    We demonstrate that mutation of xerC, which reportedly encodes a homologue of an Escherichia coli recombinase, limits biofilm formation in the methicillin-resistant Staphylococcus aureus strain LAC and the methicillin-sensitive strain UAMS-1. This was not due to the decreased production of the polysaccharide intracellular adhesin (PIA) in either strain because the amount of PIA was increased in a UAMS-1 xerC mutant and undetectable in both LAC and its isogenic xerC mutant. Mutation of xerC also resulted in the increased production of extracellular proteases and nucleases in both LAC and UAMS-1, and limiting the production of either class of enzymes increased biofilm formation in the isogenic xerC mutants. More importantly, the limited capacity to form a biofilm was correlated with increased antibiotic susceptibility in both strains in the context of an established biofilm in vivo. Mutation of xerC also attenuated virulence in a murine bacteremia model, as assessed on the basis of the bacterial loads in internal organs and overall lethality. It also resulted in the decreased accumulation of alpha toxin and the increased accumulation of protein A. These findings suggest that xerC may impact the functional status of agr. This was confirmed by demonstrating the reduced accumulation of RNAIII and AgrA in LAC and UAMS-1 xerC mutants. However, this cannot account for the biofilm-deficient phenotype of xerC mutants because mutation of agr did not limit biofilm formation in either strain. These results demonstrate that xerC contributes to biofilm-associated infections and acute bacteremia and that this is likely due to agr-independent and -dependent pathways, respectively. PMID:26857575

  11. UDP-arabinopyranose mutase 3 is required for pollen wall morphogenesis in rice (Oryza sativa).

    PubMed

    Sumiyoshi, Minako; Inamura, Takuya; Nakamura, Atsuko; Aohara, Tsutomu; Ishii, Tadashi; Satoh, Shinobu; Iwai, Hiroaki

    2015-02-01

    l-Arabinose is one of the main constituents of cell wall polysaccharides such as pectic rhamnogalacturonan I (RG-I), glucuronoarabinoxylans and other glycoproteins. It is found predominantly in the furanose form rather than in the thermodynamically more stable pyranose form. UDP-L-arabinofuranose (UDP-Araf), rather than UDP-L-arabinopyranose (UDP-Arap), is a sugar donor for the biosynthesis of arabinofuranosyl (Araf) residues. UDP-arabinopyranose mutases (UAMs) have been shown to interconvert UDP-Araf and UDP-Arap and are involved in the biosynthesis of polysaccharides including Araf. The UAM gene family has three members in Oryza sativa. Co-expression network in silico analysis showed that OsUAM3 expression was independent from OsUAM1 and OsUAM2 co-expression networks. OsUAM1 and OsUAM2 were expressed ubiquitously throughout plant development, but OsUAM3 was expressed primarily in reproductive tissue, particularly at the pollen cell wall formation developmental stage. OsUAM3 co-expression networks include pectin catabolic enzymes. To determine the function of OsUAMs in reproductive tissues, we analyzed RNA interference (RNAi)-knockdown transformants (OsUAM3-KD) specific for OsUAM3. OsUAM3-KD plants grew normally and showed abnormal phenotypes in reproductive tissues, especially in terms of the pollen cell wall and exine. In addition, we examined modifications of cell wall polysaccharides at the cellular level using antibodies against polysaccharides including Araf. Immunolocalization of arabinan using the LM6 antibody showed low levels of arabinan in OsUAM3-KD pollen grains. Our results suggest that the function of OsUAM3 is important for synthesis of arabinan side chains of RG-I and is required for reproductive developmental processes, especially the formation of the cell wall in pollen.

  12. Models, Part IV: Inquiry Models.

    ERIC Educational Resources Information Center

    Callison, Daniel

    2002-01-01

    Discusses models for information skills that include inquiry-oriented activities. Highlights include WebQuest, which uses Internet resources supplemented with videoconferencing; Minnesota's Inquiry Process based on the Big Six model for information problem-solving; Indiana's Student Inquiry Model; constructivist learning models for inquiry; and…

  13. Supermatrix models

    SciTech Connect

    Yost, S.A.

    1991-05-01

    Radom matrix models based on an integral over supermatrices are proposed as a natural extension of bosonic matrix models. The subtle nature of superspace integration allows these models to have very different properties from the analogous bosonic models. Two choices of integration slice are investigated. One leads to a perturbative structure which is reminiscent of, and perhaps identical to, the usual Hermitian matrix models. Another leads to an eigenvalue reduction which can be described by a two component plasma in one dimension. A stationary point of the model is described.

  14. Supermatrix models

    SciTech Connect

    Yost, S.A. . Dept. of Physics and Astronomy)

    1992-09-30

    In this paper, random matrix models based on an integral over supermatrices are proposed as a natural extension of bosonic matrix models. The subtle nature of superspace integration allows these models to have very different properties from the analogous bosonic models. Two choices of integration slice are investigated. One leads to a perturbative structure which is reminiscent of, and perhaps identical to, the usual Hermitian matrix models. Another leads to an eigenvalue reduction which can be described by a two-component plasma in one dimension. A stationary point of the model is described.

  15. Turbulence modeling

    NASA Technical Reports Server (NTRS)

    Rubesin, Morris W.

    1987-01-01

    Recent developments at several levels of statistical turbulence modeling applicable to aerodynamics are briefly surveyed. Emphasis is on examples of model improvements for transonic, two-dimensional flows. Experience with the development of these improved models is cited to suggest methods of accelerating the modeling process necessary to keep abreast of the rapid movement of computational fluid dynamics into the computation of complex three-dimensional flows.

  16. Architectural Models

    ERIC Educational Resources Information Center

    Levenson, Harold E.; Hurni, Andre

    1978-01-01

    Suggests building models as a way to reinforce and enhance related subjects such as architectural drafting, structural carpentry, etc., and discusses time, materials, scales, tools or equipment needed, how to achieve realistic special effects, and the types of projects that can be built (model of complete building, a panoramic model, and model…

  17. Radiation Models

    ERIC Educational Resources Information Center

    James, W. G. G.

    1970-01-01

    Discusses the historical development of both the wave and the corpuscular photon model of light. Suggests that students should be informed that the two models are complementary and that each model successfully describes a wide range of radiation phenomena. Cites 19 references which might be of interest to physics teachers and students. (LC)

  18. Hydrological models are mediating models

    NASA Astrophysics Data System (ADS)

    Babel, L. V.; Karssenberg, D.

    2013-08-01

    Despite the increasing role of models in hydrological research and decision-making processes, only few accounts of the nature and function of models exist in hydrology. Earlier considerations have traditionally been conducted while making a clear distinction between physically-based and conceptual models. A new philosophical account, primarily based on the fields of physics and economics, transcends classes of models and scientific disciplines by considering models as "mediators" between theory and observations. The core of this approach lies in identifying models as (1) being only partially dependent on theory and observations, (2) integrating non-deductive elements in their construction, and (3) carrying the role of instruments of scientific enquiry about both theory and the world. The applicability of this approach to hydrology is evaluated in the present article. Three widely used hydrological models, each showing a different degree of apparent physicality, are confronted to the main characteristics of the "mediating models" concept. We argue that irrespective of their kind, hydrological models depend on both theory and observations, rather than merely on one of these two domains. Their construction is additionally involving a large number of miscellaneous, external ingredients, such as past experiences, model objectives, knowledge and preferences of the modeller, as well as hardware and software resources. We show that hydrological models convey the role of instruments in scientific practice by mediating between theory and the world. It results from these considerations that the traditional distinction between physically-based and conceptual models is necessarily too simplistic and refers at best to the stage at which theory and observations are steering model construction. The large variety of ingredients involved in model construction would deserve closer attention, for being rarely explicitly presented in peer-reviewed literature. We believe that devoting

  19. Model Experiments and Model Descriptions

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.; Ko, Malcolm K. W.; Weisenstein, Debra; Scott, Courtney J.; Shia, Run-Lie; Rodriguez, Jose; Sze, N. D.; Vohralik, Peter; Randeniya, Lakshman; Plumb, Ian

    1999-01-01

    The Second Workshop on Stratospheric Models and Measurements Workshop (M&M II) is the continuation of the effort previously started in the first Workshop (M&M I, Prather and Remsberg [1993]) held in 1992. As originally stated, the aim of M&M is to provide a foundation for establishing the credibility of stratospheric models used in environmental assessments of the ozone response to chlorofluorocarbons, aircraft emissions, and other climate-chemistry interactions. To accomplish this, a set of measurements of the present day atmosphere was selected. The intent was that successful simulations of the set of measurements should become the prerequisite for the acceptance of these models as having a reliable prediction for future ozone behavior. This section is divided into two: model experiment and model descriptions. In the model experiment, participant were given the charge to design a number of experiments that would use observations to test whether models are using the correct mechanisms to simulate the distributions of ozone and other trace gases in the atmosphere. The purpose is closely tied to the needs to reduce the uncertainties in the model predicted responses of stratospheric ozone to perturbations. The specifications for the experiments were sent out to the modeling community in June 1997. Twenty eight modeling groups responded to the requests for input. The first part of this section discusses the different modeling group, along with the experiments performed. Part two of this section, gives brief descriptions of each model as provided by the individual modeling groups.

  20. Analytical Models

    NASA Technical Reports Server (NTRS)

    1984-01-01

    A system-level design and analysis model was developed. This model was conceived to have several key elements: a solar pond thermodynamic performance model, a power generation subsystem model, and an economic analysis element. The basic approach was to create these elements or modules and refine them on an individual basis yet retain the capability to easily couple them into a full system design model. This building block approach allows for maximum flexibility and substitution of refined descriptions as the technology develops. A general overview of interconnecting these subsystem models is presented. The primary program control element will perform the administrative functions of data input, data output, information storage and transfer, and sequential calling of the subsystem models. From the point of view of the requirements of a system design model, a power conversion subsystem model was developed. The goal of the effort was a preliminary subsystem model compatible with the solar pond subsystem model so that a first order system simulation analysis could be performed.

  1. Modeling Pharmacokinetics.

    PubMed

    Bois, Frederic Y; Brochot, Céline

    2016-01-01

    Pharmacokinetics is the study of the fate of xenobiotics in a living organism. Physiologically based pharmacokinetic (PBPK) models provide realistic descriptions of xenobiotics' absorption, distribution, metabolism, and excretion processes. They model the body as a set of homogeneous compartments representing organs, and their parameters refer to anatomical, physiological, biochemical, and physicochemical entities. They offer a quantitative mechanistic framework to understand and simulate the time-course of the concentration of a substance in various organs and body fluids. These models are well suited for performing extrapolations inherent to toxicology and pharmacology (e.g., between species or doses) and for integrating data obtained from various sources (e.g., in vitro or in vivo experiments, structure-activity models). In this chapter, we describe the practical development and basic use of a PBPK model from model building to model simulations, through implementation with an easily accessible free software. PMID:27311461

  2. ICRF modelling

    SciTech Connect

    Phillips, C.K.

    1985-12-01

    This lecture provides a survey of the methods used to model fast magnetosonic wave coupling, propagation, and absorption in tokamaks. The validity and limitations of three distinct types of modelling codes, which will be contrasted, include discrete models which utilize ray tracing techniques, approximate continuous field models based on a parabolic approximation of the wave equation, and full field models derived using finite difference techniques. Inclusion of mode conversion effects in these models and modification of the minority distribution function will also be discussed. The lecture will conclude with a presentation of time-dependent global transport simulations of ICRF-heated tokamak discharges obtained in conjunction with the ICRF modelling codes. 52 refs., 15 figs.

  3. Ventilation Model

    SciTech Connect

    H. Yang

    1999-11-04

    The purpose of this analysis and model report (AMR) for the Ventilation Model is to analyze the effects of pre-closure continuous ventilation in the Engineered Barrier System (EBS) emplacement drifts and provide heat removal data to support EBS design. It will also provide input data (initial conditions, and time varying boundary conditions) for the EBS post-closure performance assessment and the EBS Water Distribution and Removal Process Model. The objective of the analysis is to develop, describe, and apply calculation methods and models that can be used to predict thermal conditions within emplacement drifts under forced ventilation during the pre-closure period. The scope of this analysis includes: (1) Provide a general description of effects and heat transfer process of emplacement drift ventilation. (2) Develop a modeling approach to simulate the impacts of pre-closure ventilation on the thermal conditions in emplacement drifts. (3) Identify and document inputs to be used for modeling emplacement ventilation. (4) Perform calculations of temperatures and heat removal in the emplacement drift. (5) Address general considerations of the effect of water/moisture removal by ventilation on the repository thermal conditions. The numerical modeling in this document will be limited to heat-only modeling and calculations. Only a preliminary assessment of the heat/moisture ventilation effects and modeling method will be performed in this revision. Modeling of moisture effects on heat removal and emplacement drift temperature may be performed in the future.

  4. Climate Models

    NASA Technical Reports Server (NTRS)

    Druyan, Leonard M.

    2012-01-01

    Climate models is a very broad topic, so a single volume can only offer a small sampling of relevant research activities. This volume of 14 chapters includes descriptions of a variety of modeling studies for a variety of geographic regions by an international roster of authors. The climate research community generally uses the rubric climate models to refer to organized sets of computer instructions that produce simulations of climate evolution. The code is based on physical relationships that describe the shared variability of meteorological parameters such as temperature, humidity, precipitation rate, circulation, radiation fluxes, etc. Three-dimensional climate models are integrated over time in order to compute the temporal and spatial variations of these parameters. Model domains can be global or regional and the horizontal and vertical resolutions of the computational grid vary from model to model. Considering the entire climate system requires accounting for interactions between solar insolation, atmospheric, oceanic and continental processes, the latter including land hydrology and vegetation. Model simulations may concentrate on one or more of these components, but the most sophisticated models will estimate the mutual interactions of all of these environments. Advances in computer technology have prompted investments in more complex model configurations that consider more phenomena interactions than were possible with yesterday s computers. However, not every attempt to add to the computational layers is rewarded by better model performance. Extensive research is required to test and document any advantages gained by greater sophistication in model formulation. One purpose for publishing climate model research results is to present purported advances for evaluation by the scientific community.

  5. Phenomenological models

    SciTech Connect

    Braby, L.A.

    1990-09-01

    The biological effects of ionizing radiation exposure are the result of a complex sequence of physical, chemical, biochemical, and physiological interactions. One way to begin a search for an understanding of health effects of radiation is through the development of phenomenological models of the response. Many models have been presented and tested in the slowly evolving process of characterizing cellular response. A range of models covering different endpoints and phenomena has developed in parallel. Many of these models employ similar assumptions about some underlying processes while differing about the nature of others. An attempt is made to organize many of the models into groups with similar features and to compare the consequences of those features with the actual experimental observations. It is assumed that by showing that some assumptions are inconsistent with experimental observations, the job of devising and testing mechanistic models can be simplified. 43 refs., 13 figs.

  6. The ionospheric current system and its contribution to the Earth's magnetic field

    NASA Astrophysics Data System (ADS)

    Prokhorov, Boris E.; Förster, Matthias; Stolle, Claudia; Lesur, Vincent; Namgalagze, Alexander A.; Holschneider, Matthias

    2016-04-01

    The ionospheric currents are a highly variable part of the coupled Magnetosphere - Ionosphere - Thermosphere (MIT) system. This system is driven by the solar wind and Interplanetary Magnetic Field (IMF) interaction with the Earth's magnetosphere. The solar wind and IMF interactions transfer energy to the MIT system via reconnection processes at the magnetopause. The Field Aligned Currents (FACs) constitute the energetic link between the magnetosphere and the Earth's ionosphere. The system of ionospheric currents depends on the geomagnetic conditions and has significant seasonal and UT variation. The first aim of the present investigation is to model the global dynamic ionospheric current system. For this purpose, we use an improved version of the first-principle, time-dependent, and fully self-consistent numerical global Upper Atmosphere Model (UAM-P). This model describes the thermosphere, ionosphere, plasmasphere and inner magnetosphere as well as the electrodynamics of the coupled MIT system for the altitudinal range from 80 (60) km up to the 15 Earth radii. For this study, the lower latitudinal and equatorial electrodynamics of the UAM-P model was improved. The second aim of this research is to calculate the ionospheric contribution to the Earth's magnetic field. The additional magnetic field is obtained from the global ionospheric current system calculated with the UAM-P model. The ionospheric magnetic field is calculated using the Biot-Savart law. The maximum magnitudes of the ionospheric magnetic field are located close to the areas of the auroral and equatorial electrojets. The contribution of the equatorial electrojet to the magnetic field is significant and comparable to the influence of the high latitude current system.

  7. Building models

    SciTech Connect

    Burr, M.T.

    1995-04-01

    As developers make progress on independent power projects around the world, models for success are beginning to emerge. Different models are evolving to create ownership structures that accomoate a complex system of regulatory requirements. Other frameworks make use of previously untapped fuel resources, or establish new sources of financing; however, not all models may be applied to a given project. This article explores how developers are finding new alternatives for overcoming development challenges that are common to projects in many countries.

  8. Calorimetry modeling

    SciTech Connect

    Robinson, C.E.

    1990-01-01

    A heat-flow calorimeter has been modeled on a Compaq PC, using the Algor Heat Transfer Modeling and Analysis Program, Algor Interactive Systems, Inc., Pittsburgh, PA. Employed in this application of the Algor finite element analysis program are two-dimensional axisymmetric thermal conductivity elements. The development of a computer calorimeter modeling program allows for the testing of new materials and techniques without actual fabrication of the calorimeter. 2 figs.

  9. Cloud Modeling

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo; Moncrieff, Mitchell; Einaud, Franco (Technical Monitor)

    2001-01-01

    Numerical cloud models have been developed and applied extensively to study cloud-scale and mesoscale processes during the past four decades. The distinctive aspect of these cloud models is their ability to treat explicitly (or resolve) cloud-scale dynamics. This requires the cloud models to be formulated from the non-hydrostatic equations of motion that explicitly include the vertical acceleration terms since the vertical and horizontal scales of convection are similar. Such models are also necessary in order to allow gravity waves, such as those triggered by clouds, to be resolved explicitly. In contrast, the hydrostatic approximation, usually applied in global or regional models, does allow the presence of gravity waves. In addition, the availability of exponentially increasing computer capabilities has resulted in time integrations increasing from hours to days, domain grids boxes (points) increasing from less than 2000 to more than 2,500,000 grid points with 500 to 1000 m resolution, and 3-D models becoming increasingly prevalent. The cloud resolving model is now at a stage where it can provide reasonably accurate statistical information of the sub-grid, cloud-resolving processes poorly parameterized in climate models and numerical prediction models.

  10. Ventilation Model

    SciTech Connect

    V. Chipman

    2002-10-05

    The purpose of the Ventilation Model is to simulate the heat transfer processes in and around waste emplacement drifts during periods of forced ventilation. The model evaluates the effects of emplacement drift ventilation on the thermal conditions in the emplacement drifts and surrounding rock mass, and calculates the heat removal by ventilation as a measure of the viability of ventilation to delay the onset of peak repository temperature and reduce its magnitude. The heat removal by ventilation is temporally and spatially dependent, and is expressed as the fraction of heat carried away by the ventilation air compared to the fraction of heat produced by radionuclide decay. One minus the heat removal is called the wall heat fraction, or the remaining amount of heat that is transferred via conduction to the surrounding rock mass. Downstream models, such as the ''Multiscale Thermohydrologic Model'' (BSC 2001), use the wall heat fractions as outputted from the Ventilation Model to initialize their post-closure analyses. The Ventilation Model report was initially developed to analyze the effects of preclosure continuous ventilation in the Engineered Barrier System (EBS) emplacement drifts, and to provide heat removal data to support EBS design. Revision 00 of the Ventilation Model included documentation of the modeling results from the ANSYS-based heat transfer model. The purposes of Revision 01 of the Ventilation Model are: (1) To validate the conceptual model for preclosure ventilation of emplacement drifts and verify its numerical application in accordance with new procedural requirements as outlined in AP-SIII-10Q, Models (Section 7.0). (2) To satisfy technical issues posed in KTI agreement RDTME 3.14 (Reamer and Williams 2001a). Specifically to demonstrate, with respect to the ANSYS ventilation model, the adequacy of the discretization (Section 6.2.3.1), and the downstream applicability of the model results (i.e. wall heat fractions) to initialize post

  11. Model Selection for Geostatistical Models

    SciTech Connect

    Hoeting, Jennifer A.; Davis, Richard A.; Merton, Andrew A.; Thompson, Sandra E.

    2006-02-01

    We consider the problem of model selection for geospatial data. Spatial correlation is typically ignored in the selection of explanatory variables and this can influence model selection results. For example, the inclusion or exclusion of particular explanatory variables may not be apparent when spatial correlation is ignored. To address this problem, we consider the Akaike Information Criterion (AIC) as applied to a geostatistical model. We offer a heuristic derivation of the AIC in this context and provide simulation results that show that using AIC for a geostatistical model is superior to the often used approach of ignoring spatial correlation in the selection of explanatory variables. These ideas are further demonstrated via a model for lizard abundance. We also employ the principle of minimum description length (MDL) to variable selection for the geostatistical model. The effect of sampling design on the selection of explanatory covariates is also explored.

  12. Turbulence modeling

    NASA Technical Reports Server (NTRS)

    Bardina, Jorge E.

    1995-01-01

    The objective of this work is to develop, verify, and incorporate the baseline two-equation turbulence models which account for the effects of compressibility into the three-dimensional Reynolds averaged Navier-Stokes (RANS) code and to provide documented descriptions of the models and their numerical procedures so that they can be implemented into 3-D CFD codes for engineering applications.

  13. Dispersion Modeling.

    ERIC Educational Resources Information Center

    Budiansky, Stephen

    1980-01-01

    This article discusses the need for more accurate and complete input data and field verification of the various models of air pollutant dispension. Consideration should be given to changing the form of air quality standards based on enhanced dispersion modeling techniques. (Author/RE)

  14. Modeling Sunspots

    ERIC Educational Resources Information Center

    Oh, Phil Seok; Oh, Sung Jin

    2013-01-01

    Modeling in science has been studied by education researchers for decades and is now being applied broadly in school. It is among the scientific practices featured in the "Next Generation Science Standards" ("NGSS") (Achieve Inc. 2013). This article describes modeling activities in an extracurricular science club in a high…

  15. Phonological Models.

    ERIC Educational Resources Information Center

    Ballard, W.L.

    1968-01-01

    The article discusses models of synchronic and diachronic phonology and suggests changes in them. The basic generative model of phonology is outlined with the author's reinterpretations. The systematic phonemic level is questioned in terms of its unreality with respect to linguistic performance and its lack of validity with respect to historical…

  16. Student Modelers.

    ERIC Educational Resources Information Center

    Confrey, Jere; Doerr, Helen M.

    1994-01-01

    Presents an argument for learner-centered modeling tools and approaches that take into account students' conceptions. Based on a theoretical argument for the interplay of grounded activity and systematic inquiry, the article reports on a study of an integrated science and mathematics high school class that investigated modeling activities.…

  17. Protein structure modeling with MODELLER.

    PubMed

    Webb, Benjamin; Sali, Andrej

    2014-01-01

    Genome sequencing projects have resulted in a rapid increase in the number of known protein sequences. In contrast, only about one-hundredth of these sequences have been characterized at atomic resolution using experimental structure determination methods. Computational protein structure modeling techniques have the potential to bridge this sequence-structure gap. In this chapter, we present an example that illustrates the use of MODELLER to construct a comparative model for a protein with unknown structure. Automation of a similar protocol has resulted in models of useful accuracy for domains in more than half of all known protein sequences.

  18. Linguistic models and linguistic modeling.

    PubMed

    Pedryez, W; Vasilakos, A V

    1999-01-01

    The study is concerned with a linguistic approach to the design of a new category of fuzzy (granular) models. In contrast to numerically driven identification techniques, we concentrate on budding meaningful linguistic labels (granules) in the space of experimental data and forming the ensuing model as a web of associations between such granules. As such models are designed at the level of information granules and generate results in the same granular rather than pure numeric format, we refer to them as linguistic models. Furthermore, as there are no detailed numeric estimation procedures involved in the construction of the linguistic models carried out in this way, their design mode can be viewed as that of a rapid prototyping. The underlying algorithm used in the development of the models utilizes an augmented version of the clustering technique (context-based clustering) that is centered around a notion of linguistic contexts-a collection of fuzzy sets or fuzzy relations defined in the data space (more precisely a space of input variables). The detailed design algorithm is provided and contrasted with the standard modeling approaches commonly encountered in the literature. The usefulness of the linguistic mode of system modeling is discussed and illustrated with the aid of numeric studies including both synthetic data as well as some time series dealing with modeling traffic intensity over a broadband telecommunication network.

  19. UNMIX modeling of ambient PM 2.5 near an interstate highway in Cincinnati, OH, USA

    NASA Astrophysics Data System (ADS)

    Hu, Shaohua; McDonald, Rafael; Martuzevicius, Dainius; Biswas, Pratim; Grinshpun, Sergey A.; Kelley, Anna; Reponen, Tiina; Lockey, James; LeMasters, Grace

    The "Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS)" is underway to determine if infants who are exposed to diesel engine exhaust particles are at an increased risk for atopy and atopic respiratory disorders, and to determine if this effect is magnified in a genetically at risk population. In support of this study, a methodology has been developed to allocate local traffic source contributions to ambient PM 2.5 in the Cincinnati airshed. As a first step towards this allocation, UNMIX was used to generate factors for ambient PM 2.5 at two sites near at interstate highway. Procedures adopted to collect, analyze and prepare the data sets to run UNMIX are described. The factors attributed to traffic sources were similar for the two sites. These factors were also similar to locally measured truck engine-exhaust enriched ambient profiles. The temporal variation of the factors was analyzed with clear differences observed between factors attributed to traffic sources and combustion-related regional secondary sources.

  20. OSPREY Model

    SciTech Connect

    Veronica J. Rutledge

    2013-01-01

    The absence of industrial scale nuclear fuel reprocessing in the U.S. has precluded the necessary driver for developing the advanced simulation capability now prevalent in so many other countries. Thus, it is essential to model complex series of unit operations to simulate, understand, and predict inherent transient behavior and feedback loops. A capability of accurately simulating the dynamic behavior of advanced fuel cycle separation processes will provide substantial cost savings and many technical benefits. The specific fuel cycle separation process discussed in this report is the off-gas treatment system. The off-gas separation consists of a series of scrubbers and adsorption beds to capture constituents of interest. Dynamic models are being developed to simulate each unit operation involved so each unit operation can be used as a stand-alone model and in series with multiple others. Currently, an adsorption model has been developed within Multi-physics Object Oriented Simulation Environment (MOOSE) developed at the Idaho National Laboratory (INL). Off-gas Separation and REcoverY (OSPREY) models the adsorption of off-gas constituents for dispersed plug flow in a packed bed under non-isothermal and non-isobaric conditions. Inputs to the model include gas, sorbent, and column properties, equilibrium and kinetic data, and inlet conditions. The simulation outputs component concentrations along the column length as a function of time from which breakthrough data is obtained. The breakthrough data can be used to determine bed capacity, which in turn can be used to size columns. It also outputs temperature along the column length as a function of time and pressure drop along the column length. Experimental data and parameters were input into the adsorption model to develop models specific for krypton adsorption. The same can be done for iodine, xenon, and tritium. The model will be validated with experimental breakthrough curves. Customers will be given access to

  1. Model hydrographs

    USGS Publications Warehouse

    Mitchell, W.D.

    1972-01-01

    Model hydrographs are composed of pairs of dimensionless ratios, arrayed in tabular form, which, when modified by the appropriate values of rainfall exceed and by the time and areal characteristics of the drainage basin, satisfactorily represent the flood hydrograph for the basin. Model bydrographs are developed from a dimensionless translation hydrograph, having a time base of T hours and appropriately modified for storm duration by routing through reservoir storage, S=kOx. Models fall into two distinct classes: (1) those for which the value of x is unity and which have all the characteristics of true unit hydrographs and (2) those for which the value of x is other than unity and to which the unit-hydrograph principles of proportionality and superposition do not apply. Twenty-six families of linear models and eight families of nonlinear models in tabular form from the principal subject of this report. Supplemental discussions describe the development of the models and illustrate their application. Other sections of the report, supplemental to the tables, describe methods of determining the hydrograph characteristics, T, k, and x, both from observed hydrograph and from the physical characteristics of the drainage basin. Five illustrative examples of use show that the models, when properly converted to incorporate actual rainfall excess and the time and areal characteristics of the drainage basins, do indeed satisfactorily represent the observed flood hydrographs for the basins.

  2. Stereometric Modelling

    NASA Astrophysics Data System (ADS)

    Grimaldi, P.

    2012-07-01

    These mandatory guidelines are provided for preparation of papers accepted for publication in the series of Volumes of The The stereometric modelling means modelling achieved with : - the use of a pair of virtual cameras, with parallel axes and positioned at a mutual distance average of 1/10 of the distance camera-object (in practice the realization and use of a stereometric camera in the modeling program); - the shot visualization in two distinct windows - the stereoscopic viewing of the shot while modelling. Since the definition of "3D vision" is inaccurately referred to as the simple perspective of an object, it is required to add the word stereo so that "3D stereo vision " shall stand for "three-dimensional view" and ,therefore, measure the width, height and depth of the surveyed image. Thanks to the development of a stereo metric model , either real or virtual, through the "materialization", either real or virtual, of the optical-stereo metric model made visible with a stereoscope. It is feasible a continuous on line updating of the cultural heritage with the help of photogrammetry and stereometric modelling. The catalogue of the Architectonic Photogrammetry Laboratory of Politecnico di Bari is available on line at: http://rappresentazione.stereofot.it:591/StereoFot/FMPro?-db=StereoFot.fp5&-lay=Scheda&-format=cerca.htm&-view

  3. Phenomenological models.

    PubMed

    Braby, L A

    1991-01-01

    The biological effects of ionizing radiation exposure are the result of a complex sequence of physical, chemical, biochemical, and physiological interactions which are modified by characteristics of the radiation, the timing of its administration, the chemical and physical environment, and the nature of the biological system. However, it is generally agreed that the health effects in animals originate from changes in individual cells, or possibly small groups of cells, and that these cellular changes are initiated by ionizations and excitations produced by the passage of charged particles through the cells. One way to begin a search for an understanding of health effects of radiation is through the development of phenomenological models of the response. Many models have been presented and tested in the slowly evolving process of characterizing cellular response. Different phenomena (LET dependence, dose rate effect, oxygen effect etc.) and different end points (cell survival, aberration formation, transformation, etc.) have been observed, and no single model has been developed to cover all of them. Instead, a range of models covering different end points and phenomena have developed in parallel. Many of these models employ similar assumptions about some underlying processes while differing about the nature of others. An attempt is made to organize many of the models into groups with similar features and to compare the consequences of those features with the actual experimental observations. It is assumed that by showing that some assumptions are inconsistent with experimental observations, the job of devising and testing mechanistic models can be simplified. PMID:1811477

  4. Phenomenological models.

    PubMed

    Braby, L A

    1991-01-01

    The biological effects of ionizing radiation exposure are the result of a complex sequence of physical, chemical, biochemical, and physiological interactions which are modified by characteristics of the radiation, the timing of its administration, the chemical and physical environment, and the nature of the biological system. However, it is generally agreed that the health effects in animals originate from changes in individual cells, or possibly small groups of cells, and that these cellular changes are initiated by ionizations and excitations produced by the passage of charged particles through the cells. One way to begin a search for an understanding of health effects of radiation is through the development of phenomenological models of the response. Many models have been presented and tested in the slowly evolving process of characterizing cellular response. Different phenomena (LET dependence, dose rate effect, oxygen effect etc.) and different end points (cell survival, aberration formation, transformation, etc.) have been observed, and no single model has been developed to cover all of them. Instead, a range of models covering different end points and phenomena have developed in parallel. Many of these models employ similar assumptions about some underlying processes while differing about the nature of others. An attempt is made to organize many of the models into groups with similar features and to compare the consequences of those features with the actual experimental observations. It is assumed that by showing that some assumptions are inconsistent with experimental observations, the job of devising and testing mechanistic models can be simplified.

  5. Modular Modeling System Model Builder

    SciTech Connect

    McKim, C.S.; Matthews, M.T.

    1996-12-31

    The latest release of the Modular Modeling System (MMS) Model Builder adds still more time-saving features to an already powerful MMS dynamic-simulation tool set. The Model Builder takes advantage of 32-bit architecture within the Microsoft Windows 95/NT{trademark} Operating Systems to better integrate a mature library of power-plant components. In addition, the MMS Library of components can now be modified and extended with a new tool named MMS CompGen{trademark}. The MMS Model Builder allows the user to quickly build a graphical schematic representation for a plant by selecting from a library of predefined power plant components to dynamically simulate their operation. In addition, each component has a calculation subroutine stored in a dynamic-link library (DLL), which facilitates the determination of a steady-state condition and performance of routine calculations for the component. These calculations, termed auto-parameterization, help avoid repetitive and often tedious hand calculations for model initialization. In striving to meet the needs for large models and increase user productivity, the MMS Model Builder has been completely revamped to make power plant model creation and maintainability easier and more efficient.

  6. A Model for Math Modeling

    ERIC Educational Resources Information Center

    Lin, Tony; Erfan, Sasan

    2016-01-01

    Mathematical modeling is an open-ended research subject where no definite answers exist for any problem. Math modeling enables thinking outside the box to connect different fields of studies together including statistics, algebra, calculus, matrices, programming and scientific writing. As an integral part of society, it is the foundation for many…

  7. Energy Models

    EPA Science Inventory

    Energy models characterize the energy system, its evolution, and its interactions with the broader economy. The energy system consists of primary resources, including both fossil fuels and renewables; power plants, refineries, and other technologies to process and convert these r...

  8. Modeling Arcs

    SciTech Connect

    Insepov, Z.; Norem, J.; Vetizer, S.; Mahalingam, S.

    2011-12-23

    Although vacuum arcs were first identified over 110 years ago, they are not yet well understood. We have since developed a model of breakdown and gradient limits that tries to explain, in a self-consistent way: arc triggering, plasma initiation, plasma evolution, surface damage and gradient limits. We use simple PIC codes for modeling plasmas, molecular dynamics for modeling surface breakdown, and surface damage, and mesoscale surface thermodynamics and finite element electrostatic codes for to evaluate surface properties. Since any given experiment seems to have more variables than data points, we have tried to consider a wide variety of arcing (rf structures, e beam welding, laser ablation, etc.) to help constrain the problem, and concentrate on common mechanisms. While the mechanisms can be comparatively simple, modeling can be challenging.

  9. Programming models

    SciTech Connect

    Daniel, David J; Mc Pherson, Allen; Thorp, John R; Barrett, Richard; Clay, Robert; De Supinski, Bronis; Dube, Evi; Heroux, Mike; Janssen, Curtis; Langer, Steve; Laros, Jim

    2011-01-14

    A programming model is a set of software technologies that support the expression of algorithms and provide applications with an abstract representation of the capabilities of the underlying hardware architecture. The primary goals are productivity, portability and performance.

  10. PREDICTIVE MODELS

    SciTech Connect

    Ray, R.M. )

    1986-12-01

    PREDICTIVE MODELS is a collection of five models - CFPM, CO2PM, ICPM, PFPM, and SFPM - used in the 1982-1984 National Petroleum Council study of enhanced oil recovery (EOR) potential. Each pertains to a specific EOR process designed to squeeze additional oil from aging or spent oil fields. The processes are: 1) chemical flooding, where soap-like surfactants are injected into the reservoir to wash out the oil; 2) carbon dioxide miscible flooding, where carbon dioxide mixes with the lighter hydrocarbons making the oil easier to displace; 3) in-situ combustion, which uses the heat from burning some of the underground oil to thin the product; 4) polymer flooding, where thick, cohesive material is pumped into a reservoir to push the oil through the underground rock; and 5) steamflood, where pressurized steam is injected underground to thin the oil. CFPM, the Chemical Flood Predictive Model, models micellar (surfactant)-polymer floods in reservoirs, which have been previously waterflooded to residual oil saturation. Thus, only true tertiary floods are considered. An option allows a rough estimate of oil recovery by caustic or caustic-polymer processes. CO2PM, the Carbon Dioxide miscible flooding Predictive Model, is applicable to both secondary (mobile oil) and tertiary (residual oil) floods, and to either continuous CO2 injection or water-alternating gas processes. ICPM, the In-situ Combustion Predictive Model, computes the recovery and profitability of an in-situ combustion project from generalized performance predictive algorithms. PFPM, the Polymer Flood Predictive Model, is switch-selectable for either polymer or waterflooding, and an option allows the calculation of the incremental oil recovery and economics of polymer relative to waterflooding. SFPM, the Steamflood Predictive Model, is applicable to the steam drive process, but not to cyclic steam injection (steam soak) processes.

  11. Mechanistic models

    SciTech Connect

    Curtis, S.B.

    1990-09-01

    Several models and theories are reviewed that incorporate the idea of radiation-induced lesions (repairable and/or irreparable) that can be related to molecular lesions in the DNA molecule. Usually the DNA double-strand or chromatin break is suggested as the critical lesion. In the models, the shoulder on the low-LET survival curve is hypothesized as being due to one (or more) of the following three mechanisms: (1) interaction'' of lesions produced by statistically independent particle tracks; (2) nonlinear (i.e., linear-quadratic) increase in the yield of initial lesions, and (3) saturation of repair processes at high dose. Comparisons are made between the various approaches. Several significant advances in model development are discussed; in particular, a description of the matrix formulation of the Markov versions of the RMR and LPL models is given. The more advanced theories have incorporated statistical fluctuations in various aspects of the energy-loss and lesion-formation process. An important direction is the inclusion of physical and chemical processes into the formulations by incorporating relevant track structure theory (Monte Carlo track simulations) and chemical reactions of radiation-induced radicals. At the biological end, identification of repair genes and how they operate as well as a better understanding of how DNA misjoinings lead to lethal chromosome aberrations are needed for appropriate inclusion into the theories. More effort is necessary to model the complex end point of radiation-induced carcinogenesis.

  12. Mechanistic models

    SciTech Connect

    Curtis, S.B.

    1990-09-01

    Several models and theories are reviewed that incorporate the idea of radiation-induced lesions (repairable and/or irreparable) that can be related to molecular lesions in the DNA molecule. Usually the DNA double-strand or chromatin break is suggested as the critical lesion. In the models, the shoulder on the low-LET survival curve is hypothesized as being due to one (or more) of the following three mechanisms: (1) ``interaction`` of lesions produced by statistically independent particle tracks; (2) nonlinear (i.e., linear-quadratic) increase in the yield of initial lesions, and (3) saturation of repair processes at high dose. Comparisons are made between the various approaches. Several significant advances in model development are discussed; in particular, a description of the matrix formulation of the Markov versions of the RMR and LPL models is given. The more advanced theories have incorporated statistical fluctuations in various aspects of the energy-loss and lesion-formation process. An important direction is the inclusion of physical and chemical processes into the formulations by incorporating relevant track structure theory (Monte Carlo track simulations) and chemical reactions of radiation-induced radicals. At the biological end, identification of repair genes and how they operate as well as a better understanding of how DNA misjoinings lead to lethal chromosome aberrations are needed for appropriate inclusion into the theories. More effort is necessary to model the complex end point of radiation-induced carcinogenesis.

  13. Ultrasonic Additive Manufacturing: Weld Optimization for Aluminum 6061, Development of Scarf Joints for Aluminum Sheet Metal, and Joining of High Strength Metals

    NASA Astrophysics Data System (ADS)

    Wolcott, Paul J.

    Ultrasonic additive manufacturing (UAM) is a low temperature, solid-state manufacturing process that enables the creation of layered, solid metal structures with designed anisotropies and embedded materials. As a low temperature process, UAM enables the creation of active composites containing smart materials, components with embedded sensors, thermal management devices, and many others. The focus of this work is on the improvement and characterization of UAM aluminum structures, advancing the capabilities of ultrasonic joining into sheet geometries, and examination of dissimilar material joints using the technology. Optimized process parameters for Al 6061 were identified via a design of experiments study indicating a weld amplitude of 32.8 synum and a weld speed of 200 in/min as optimal. Weld force and temperature were not significant within the levels studied. A methodology of creating large scale builds is proposed, including a prescribed random stacking sequence and overlap of 0.0035 in. (0.0889 mm) for foils to minimize voids and maximize mechanical strength. Utilization of heat treatments is shown to significantly increase mechanical properties of UAM builds, within 90% of bulk material. The applied loads during the UAM process were investigated to determine the stress fields and plastic deformation induced during the process. Modeling of the contact mechanics via Hertzian contact equations shows that significant stress is applied via sonotrode contact in the process. Contact modeling using finite element analysis (FEA), including plasticity, indicates that 5000 N normal loads result in plastic deformation in bulk aluminum foil, while at 3000 N no plastic deformation occurs. FEA studies on the applied loads during the process, specifically a 3000 N normal force and 2000 N shear force, show that high stresses and plastic deformation occur at the edges of a welded foil, and base of the UAM build. Microstructural investigations of heat treated foils confirms

  14. Modeling reality

    NASA Technical Reports Server (NTRS)

    Denning, Peter J.

    1990-01-01

    Although powerful computers have allowed complex physical and manmade hardware systems to be modeled successfully, we have encountered persistent problems with the reliability of computer models for systems involving human learning, human action, and human organizations. This is not a misfortune; unlike physical and manmade systems, human systems do not operate under a fixed set of laws. The rules governing the actions allowable in the system can be changed without warning at any moment, and can evolve over time. That the governing laws are inherently unpredictable raises serious questions about the reliability of models when applied to human situations. In these domains, computers are better used, not for prediction and planning, but for aiding humans. Examples are systems that help humans speculate about possible futures, offer advice about possible actions in a domain, systems that gather information from the networks, and systems that track and support work flows in organizations.

  15. Supernova models

    SciTech Connect

    Woosley, S.E.; Weaver, T.A.

    1980-01-01

    Recent progress in understanding the observed properties of Type I supernovae as a consequence of the thermonuclear detonation of white dwarf stars and the ensuing decay of the /sup 56/Ni produced therein is reviewed. Within the context of this model for Type I explosions and the 1978 model for Type II explosions, the expected nucleosynthesis and gamma-line spectra from both kinds of supernovae are presented. Finally, a qualitatively new approach to the problem of massive star death and Type II supernovae based upon a combination of rotation and thermonuclear burning is discussed.

  16. Painting models

    NASA Astrophysics Data System (ADS)

    Baart, F.; Donchyts, G.; van Dam, A.; Plieger, M.

    2015-12-01

    The emergence of interactive art has blurred the line between electronic, computer graphics and art. Here we apply this art form to numerical models. Here we show how the transformation of a numerical model into an interactive painting can both provide insights and solve real world problems. The cases that are used as an example include forensic reconstructions, dredging optimization, barrier design. The system can be fed using any source of time varying vector fields, such as hydrodynamic models. The cases used here, the Indian Ocean (HYCOM), the Wadden Sea (Delft3D Curvilinear), San Francisco Bay (3Di subgrid and Delft3D Flexible Mesh), show that the method used is suitable for different time and spatial scales. High resolution numerical models become interactive paintings by exchanging their velocity fields with a high resolution (>=1M cells) image based flow visualization that runs in a html5 compatible web browser. The image based flow visualization combines three images into a new image: the current image, a drawing, and a uv + mask field. The advection scheme that computes the resultant image is executed in the graphics card using WebGL, allowing for 1M grid cells at 60Hz performance on mediocre graphic cards. The software is provided as open source software. By using different sources for a drawing one can gain insight into several aspects of the velocity fields. These aspects include not only the commonly represented magnitude and direction, but also divergence, topology and turbulence .

  17. Atmospheric Modeling

    EPA Science Inventory

    Although air quality models have been applied historically to address issues specific to ambient air quality standards (i.e., one criteria pollutant at a time) or welfare (e.g.. acid deposition or visibility impairment). they are inherently multipollutant based. Therefore. in pri...

  18. Modeling Muscles

    ERIC Educational Resources Information Center

    Goodwyn, Lauren; Salm, Sarah

    2007-01-01

    Teaching the anatomy of the muscle system to high school students can be challenging. Students often learn about muscle anatomy by memorizing information from textbooks or by observing plastic, inflexible models. Although these mediums help students learn about muscle placement, the mediums do not facilitate understanding regarding integration of…

  19. Modeling Convection

    ERIC Educational Resources Information Center

    Ebert, James R.; Elliott, Nancy A.; Hurteau, Laura; Schulz, Amanda

    2004-01-01

    Students must understand the fundamental process of convection before they can grasp a wide variety of Earth processes, many of which may seem abstract because of the scales on which they operate. Presentation of a very visual, concrete model prior to instruction on these topics may facilitate students' understanding of processes that are largely…

  20. Ensemble Models

    EPA Science Inventory

    Ensemble forecasting has been used for operational numerical weather prediction in the United States and Europe since the early 1990s. An ensemble of weather or climate forecasts is used to characterize the two main sources of uncertainty in computer models of physical systems: ...

  1. Criticality Model

    SciTech Connect

    A. Alsaed

    2004-09-14

    The ''Disposal Criticality Analysis Methodology Topical Report'' (YMP 2003) presents the methodology for evaluating potential criticality situations in the monitored geologic repository. As stated in the referenced Topical Report, the detailed methodology for performing the disposal criticality analyses will be documented in model reports. Many of the models developed in support of the Topical Report differ from the definition of models as given in the Office of Civilian Radioactive Waste Management procedure AP-SIII.10Q, ''Models'', in that they are procedural, rather than mathematical. These model reports document the detailed methodology necessary to implement the approach presented in the Disposal Criticality Analysis Methodology Topical Report and provide calculations utilizing the methodology. Thus, the governing procedure for this type of report is AP-3.12Q, ''Design Calculations and Analyses''. The ''Criticality Model'' is of this latter type, providing a process evaluating the criticality potential of in-package and external configurations. The purpose of this analysis is to layout the process for calculating the criticality potential for various in-package and external configurations and to calculate lower-bound tolerance limit (LBTL) values and determine range of applicability (ROA) parameters. The LBTL calculations and the ROA determinations are performed using selected benchmark experiments that are applicable to various waste forms and various in-package and external configurations. The waste forms considered in this calculation are pressurized water reactor (PWR), boiling water reactor (BWR), Fast Flux Test Facility (FFTF), Training Research Isotope General Atomic (TRIGA), Enrico Fermi, Shippingport pressurized water reactor, Shippingport light water breeder reactor (LWBR), N-Reactor, Melt and Dilute, and Fort Saint Vrain Reactor spent nuclear fuel (SNF). The scope of this analysis is to document the criticality computational method. The criticality

  2. Contribution of the nos-pdt Operon to Virulence Phenotypes in Methicillin-Sensitive Staphylococcus aureus

    PubMed Central

    Almand, Erin A.; Rivera, Frances E.; Shaw, Lindsey N.; Richardson, Anthony R.; Rice, Kelly C.

    2014-01-01

    Nitric oxide (NO) is emerging as an important regulator of bacterial stress resistance, biofilm development, and virulence. One potential source of endogenous NO production in the pathogen Staphylococcus aureus is its NO-synthase (saNOS) enzyme, encoded by the nos gene. Although a role for saNOS in oxidative stress resistance, antibiotic resistance, and virulence has been recently-described, insights into the regulation of nos expression and saNOS enzyme activity remain elusive. To this end, transcriptional analysis of the nos gene in S. aureus strain UAMS-1 was performed, which revealed that nos expression increases during low-oxygen growth and is growth-phase dependent. Furthermore, nos is co-transcribed with a downstream gene, designated pdt, which encodes a prephenate dehydratase (PDT) enzyme involved in phenylalanine biosynthesis. Deletion of pdt significantly impaired the ability of UAMS-1 to grow in chemically-defined media lacking phenylalanine, confirming the function of this enzyme. Bioinformatics analysis revealed that the operon organization of nos-pdt appears to be unique to the staphylococci. As described for other S. aureus nos mutants, inactivation of nos in UAMS-1 conferred sensitivity to oxidative stress, while deletion of pdt did not affect this phenotype. The nos mutant also displayed reduced virulence in a murine sepsis infection model, and increased carotenoid pigmentation when cultured on agar plates, both previously-undescribed nos mutant phenotypes. Utilizing the fluorescent stain 4-Amino-5-Methylamino-2',7'-Difluorofluorescein (DAF-FM) diacetate, decreased levels of intracellular NO/reactive nitrogen species (RNS) were detected in the nos mutant on agar plates. These results reinforce the important role of saNOS in S. aureus physiology and virulence, and have identified an in vitro growth condition under which saNOS activity appears to be upregulated. However, the significance of the operon organization of nos-pdt and potential

  3. Contribution of the nos-pdt operon to virulence phenotypes in methicillin-sensitive Staphylococcus aureus.

    PubMed

    Sapp, April M; Mogen, Austin B; Almand, Erin A; Rivera, Frances E; Shaw, Lindsey N; Richardson, Anthony R; Rice, Kelly C

    2014-01-01

    Nitric oxide (NO) is emerging as an important regulator of bacterial stress resistance, biofilm development, and virulence. One potential source of endogenous NO production in the pathogen Staphylococcus aureus is its NO-synthase (saNOS) enzyme, encoded by the nos gene. Although a role for saNOS in oxidative stress resistance, antibiotic resistance, and virulence has been recently-described, insights into the regulation of nos expression and saNOS enzyme activity remain elusive. To this end, transcriptional analysis of the nos gene in S. aureus strain UAMS-1 was performed, which revealed that nos expression increases during low-oxygen growth and is growth-phase dependent. Furthermore, nos is co-transcribed with a downstream gene, designated pdt, which encodes a prephenate dehydratase (PDT) enzyme involved in phenylalanine biosynthesis. Deletion of pdt significantly impaired the ability of UAMS-1 to grow in chemically-defined media lacking phenylalanine, confirming the function of this enzyme. Bioinformatics analysis revealed that the operon organization of nos-pdt appears to be unique to the staphylococci. As described for other S. aureus nos mutants, inactivation of nos in UAMS-1 conferred sensitivity to oxidative stress, while deletion of pdt did not affect this phenotype. The nos mutant also displayed reduced virulence in a murine sepsis infection model, and increased carotenoid pigmentation when cultured on agar plates, both previously-undescribed nos mutant phenotypes. Utilizing the fluorescent stain 4-Amino-5-Methylamino-2',7'-Difluorofluorescein (DAF-FM) diacetate, decreased levels of intracellular NO/reactive nitrogen species (RNS) were detected in the nos mutant on agar plates. These results reinforce the important role of saNOS in S. aureus physiology and virulence, and have identified an in vitro growth condition under which saNOS activity appears to be upregulated. However, the significance of the operon organization of nos-pdt and potential

  4. Models, Part V: Composition Models.

    ERIC Educational Resources Information Center

    Callison, Daniel

    2003-01-01

    Describes four models: The Authoring Cycle, a whole language approach that reflects the inquiry process; I-Search, an approach to research that uses the power of student interests; Cultural Celebration, using local heritage topics; and Science Lab Report, for the composition of a lab report. (LRW)

  5. Modeling Molecules

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The molecule modeling method known as Multibody Order (N) Dynamics, or MBO(N)D, was developed by Moldyn, Inc. at Goddard Space Flight Center through funding provided by the SBIR program. The software can model the dynamics of molecules through technology which stimulates low-frequency molecular motions and properties, such as movements among a molecule's constituent parts. With MBO(N)D, a molecule is substructured into a set of interconnected rigid and flexible bodies. These bodies replace the computation burden of mapping individual atoms. Moldyn's technology cuts computation time while increasing accuracy. The MBO(N)D technology is available as Insight II 97.0 from Molecular Simulations, Inc. Currently the technology is used to account for forces on spacecraft parts and to perform molecular analyses for pharmaceutical purposes. It permits the solution of molecular dynamics problems on a moderate workstation, as opposed to on a supercomputer.

  6. Dendrite Model

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Dr. Donald Gilles, the Discipline Scientist for Materials Science in NASA's Microgravity Materials Science and Applications Department, demonstrates to Carl Dohrman a model of dendrites, the branch-like structures found in many metals and alloys. Dohrman was recently selected by the American Society for Metals International as their 1999 ASM International Foundation National Merit Scholar. The University of Illinois at Urbana-Champaign freshman recently toured NASA's materials science facilities at the Marshall Space Flight Center.

  7. Modeling biomembranes.

    SciTech Connect

    Plimpton, Steven James; Heffernan, Julieanne; Sasaki, Darryl Yoshio; Frischknecht, Amalie Lucile; Stevens, Mark Jackson; Frink, Laura J. Douglas

    2005-11-01

    Understanding the properties and behavior of biomembranes is fundamental to many biological processes and technologies. Microdomains in biomembranes or ''lipid rafts'' are now known to be an integral part of cell signaling, vesicle formation, fusion processes, protein trafficking, and viral and toxin infection processes. Understanding how microdomains form, how they depend on membrane constituents, and how they act not only has biological implications, but also will impact Sandia's effort in development of membranes that structurally adapt to their environment in a controlled manner. To provide such understanding, we created physically-based models of biomembranes. Molecular dynamics (MD) simulations and classical density functional theory (DFT) calculations using these models were applied to phenomena such as microdomain formation, membrane fusion, pattern formation, and protein insertion. Because lipid dynamics and self-organization in membranes occur on length and time scales beyond atomistic MD, we used coarse-grained models of double tail lipid molecules that spontaneously self-assemble into bilayers. DFT provided equilibrium information on membrane structure. Experimental work was performed to further help elucidate the fundamental membrane organization principles.

  8. Model checking

    NASA Technical Reports Server (NTRS)

    Dill, David L.

    1995-01-01

    Automatic formal verification methods for finite-state systems, also known as model-checking, successfully reduce labor costs since they are mostly automatic. Model checkers explicitly or implicitly enumerate the reachable state space of a system, whose behavior is described implicitly, perhaps by a program or a collection of finite automata. Simple properties, such as mutual exclusion or absence of deadlock, can be checked by inspecting individual states. More complex properties, such as lack of starvation, require search for cycles in the state graph with particular properties. Specifications to be checked may consist of built-in properties, such as deadlock or 'unspecified receptions' of messages, another program or implicit description, to be compared with a simulation, bisimulation, or language inclusion relation, or an assertion in one of several temporal logics. Finite-state verification tools are beginning to have a significant impact in commercial designs. There are many success stories of verification tools finding bugs in protocols or hardware controllers. In some cases, these tools have been incorporated into design methodology. Research in finite-state verification has been advancing rapidly, and is showing no signs of slowing down. Recent results include probabilistic algorithms for verification, exploitation of symmetry and independent events, and the use symbolic representations for Boolean functions and systems of linear inequalities. One of the most exciting areas for further research is the combination of model-checking with theorem-proving methods.

  9. Molecular Modeling

    NASA Astrophysics Data System (ADS)

    Holmes, Jon L.

    1999-06-01

    Molecular modeling has trickled down from the realm of pharmaceutical and research laboratories into the realm of undergraduate chemistry instruction. It has opened avenues for the visualization of chemical concepts that previously were difficult or impossible to convey. I am sure that many of you have developed exercises using the various molecular modeling tools. It is the desire of this Journal to become an avenue for you to share these exercises among your colleagues. It is to this end that Ron Starkey has agreed to edit such a column and to publish not only the description of such exercises, but also the software documents they use. The WWW is the obvious medium to distribute this combination and so accepted submissions will appear online as a feature of JCE Internet. Typical molecular modeling exercise: finding conformation energies. Molecular Modeling Exercises and Experiments is the latest feature column of JCE Internet, joining Conceptual Questions and Challenge Problems, Hal's Picks, and Mathcad in the Chemistry Curriculum. JCE Internet continues to seek submissions in these areas of interest and submissions of general interest. If you have developed materials and would like to submit them, please see our Guide to Submissions for more information. The Chemical Education Resource Shelf, Equipment Buyers Guide, and WWW Site Review would also like to hear about chemistry textbooks and software, equipment, and WWW sites, respectively. Please consult JCE Internet Features to learn more about these resources at JCE Online. Email Announcements Would you like to be informed by email when the latest issue of the Journal is available online? when a new JCE Software title is shipping? when a new JCE Internet article has been published or is available for Open Review? when your subscription is about to expire? A new feature of JCE Online makes this possible. Visit our Guestbook to learn how. When

  10. Students' Models of Curve Fitting: A Models and Modeling Perspective

    ERIC Educational Resources Information Center

    Gupta, Shweta

    2010-01-01

    The Models and Modeling Perspectives (MMP) has evolved out of research that began 26 years ago. MMP researchers use Model Eliciting Activities (MEAs) to elicit students' mental models. In this study MMP was used as the conceptual framework to investigate the nature of students' models of curve fitting in a problem-solving environment consisting of…

  11. 10. MOVABLE BED SEDIMENTATION MODELS. DOGTOOTH BEND MODEL (MODEL SCALE: ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. MOVABLE BED SEDIMENTATION MODELS. DOGTOOTH BEND MODEL (MODEL SCALE: 1' = 400' HORIZONTAL, 1' = 100' VERTICAL), AND GREENVILLE BRIDGE MODEL (MODEL SCALE: 1' = 360' HORIZONTAL, 1' = 100' VERTICAL). - Waterways Experiment Station, Hydraulics Laboratory, Halls Ferry Road, 2 miles south of I-20, Vicksburg, Warren County, MS

  12. Biomimetic modelling.

    PubMed Central

    Vincent, Julian F V

    2003-01-01

    Biomimetics is seen as a path from biology to engineering. The only path from engineering to biology in current use is the application of engineering concepts and models to biological systems. However, there is another pathway: the verification of biological mechanisms by manufacture, leading to an iterative process between biology and engineering in which the new understanding that the engineering implementation of a biological system can bring is fed back into biology, allowing a more complete and certain understanding and the possibility of further revelations for application in engineering. This is a pathway as yet unformalized, and one that offers the possibility that engineers can also be scientists. PMID:14561351

  13. Fault models

    NASA Astrophysics Data System (ADS)

    Sayah, H. R.; Buehler, M. G.

    1985-06-01

    A major problem in the qualification of integrated circuit cells and in the development of adequate tests for the circuits is to lack of information on the nature and density of fault models. Some of this information is being obtained from the test structures. In particular, the Pinhole Array Capacitor is providing values for the resistance of gate oxide shorts, and the Addressable Inverter Matrix is providing values for parameter distributions such as noise margins. Another CMOS fault mode, that of the open-gated transistor, is examined and the state of the transistors assessed. Preliminary results are described for a number of open-gated structures such as transistors, inverters, and NAND gates. Resistor faults are applied to various CMOS gates and the time responses are noted. The critical value for the resistive short to upset the gate response was determined.

  14. Modeling uncertainty: quicksand for water temperature modeling

    USGS Publications Warehouse

    Bartholow, John M.

    2003-01-01

    Uncertainty has been a hot topic relative to science generally, and modeling specifically. Modeling uncertainty comes in various forms: measured data, limited model domain, model parameter estimation, model structure, sensitivity to inputs, modelers themselves, and users of the results. This paper will address important components of uncertainty in modeling water temperatures, and discuss several areas that need attention as the modeling community grapples with how to incorporate uncertainty into modeling without getting stuck in the quicksand that prevents constructive contributions to policy making. The material, and in particular the reference, are meant to supplement the presentation given at this conference.

  15. Pre-Modeling Ensures Accurate Solid Models

    ERIC Educational Resources Information Center

    Gow, George

    2010-01-01

    Successful solid modeling requires a well-organized design tree. The design tree is a list of all the object's features and the sequential order in which they are modeled. The solid-modeling process is faster and less prone to modeling errors when the design tree is a simple and geometrically logical definition of the modeled object. Few high…

  16. CISNET lung models: Comparison of model assumptions and model structures

    PubMed Central

    McMahon, Pamela M.; Hazelton, William; Kimmel, Marek; Clarke, Lauren

    2012-01-01

    Sophisticated modeling techniques can be powerful tools to help us understand the effects of cancer control interventions on population trends in cancer incidence and mortality. Readers of journal articles are however rarely supplied with modeling details. Six modeling groups collaborated as part of the National Cancer Institute’s Cancer Intervention and Surveillance Modeling Network (CISNET) to investigate the contribution of US tobacco control efforts towards reducing lung cancer deaths over the period 1975 to 2000. The models included in this monograph were developed independently and use distinct, complementary approaches towards modeling the natural history of lung cancer. The models used the same data for inputs and agreed on the design of the analysis and the outcome measures. This article highlights aspects of the models that are most relevant to similarities of or differences between the results. Structured comparisons can increase the transparency of these complex models. PMID:22882887

  17. 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…

  18. I&C Modeling in SPAR Models

    SciTech Connect

    John A. Schroeder

    2012-06-01

    The Standardized Plant Analysis Risk (SPAR) models for the U.S. commercial nuclear power plants currently have very limited instrumentation and control (I&C) modeling [1]. Most of the I&C components in the operating plant SPAR models are related to the reactor protection system. This was identified as a finding during the industry peer review of SPAR models. While the Emergency Safeguard Features (ESF) actuation and control system was incorporated into the Peach Bottom Unit 2 SPAR model in a recent effort [2], various approaches to expend resources for detailed I&C modeling in other SPAR models are investigated.

  19. Comparative Protein Structure Modeling Using MODELLER.

    PubMed

    Webb, Benjamin; Sali, Andrej

    2014-09-08

    Functional characterization of a protein sequence is one of the most frequent problems in biology. This task is usually facilitated by accurate three-dimensional (3-D) structure of the studied protein. In the absence of an experimentally determined structure, comparative or homology modeling can sometimes provide a useful 3-D model for a protein that is related to at least one known protein structure. Comparative modeling predicts the 3-D structure of a given protein sequence (target) based primarily on its alignment to one or more proteins of known structure (templates). The prediction process consists of fold assignment, target-template alignment, model building, and model evaluation. This unit describes how to calculate comparative models using the program MODELLER and discusses all four steps of comparative modeling, frequently observed errors, and some applications. Modeling lactate dehydrogenase from Trichomonas vaginalis (TvLDH) is described as an example. The download and installation of the MODELLER software is also described.

  20. Thermosphere and ionosphere response on seismogenic disturbances of the global electric circuit

    NASA Astrophysics Data System (ADS)

    Karpov, Mikhail; Namgaladze, Aleksandr; Knyazeva, Maria

    2016-04-01

    Conditions of warm, humid and ionized air over the active tectonic faults favor the formation of clouds and generation of the intense vertical electric current between the Earth and ionosphere. The latter arises due to separation and vertical transport of the oppositely charged particles by the gravity force and pressure gradients. Additional transport of charged particles into the ionosphere causes disturbances of the ionosphere plasma (under the action of the electric currents in the E-layer and electromagnetic plasma drift in the F2-layer) and thermosphere neutral gas (via the momentum transfer from electric to neutral particles). The thermosphere and ionosphere variations formed under the action of the electric field created by this vertical electric current have been calculated by using the Upper Atmosphere Model (UAM), and a good agreement was found between observed and the UAM calculated perturbations of the electric field, electron and ion concentrations, total electron content (TEC), ion and electron temperatures as well as wind velocities and neutral gas temeperature and concentrations. The roles of the internal gravity waves and electromagnetic plasma drift in generation of the seismogenic TEC variations are discussed.

  1. Interfacial shear strength estimates of NiTi-Al matrix composites fabricated via ultrasonic additive manufacturing

    NASA Astrophysics Data System (ADS)

    Hehr, Adam; Pritchard, Joshua; Dapino, Marcelo J.

    2014-03-01

    The purpose of this study is to understand and improve the interfacial shear strength of metal matrix composites fabricated via very high power (VHP) ultrasonic additive manufacturing (UAM). VHP-UAM NiTi-Al composites have shown a dramatic decrease in thermal expansion compared to Al, yet thermal blocking stresses developed during thermal cycling have been found to degrade and eventually cause interface failure. Consequently, to improve understanding of the interface and guide the development of stronger NiTi- Al composites, the interface strength was investigated through the use of single ber pullout tests. It was found that the matrix yielded prior to the interface breaking since adhered aluminum was consistently observed on all pullout samples. Additionally, measured pullout loads were utilized as an input to a nite element model for stress and shear lag analysis, which, in turn showed that the Al matrix experienced a peak shear stress near 230 MPa. This stress is above the Al matrix's ultimate shear strength of 150-200 MPa, thus this large stress corroborates with matrix failure observed during testing. The in uence of various ber surface treatments on bond mechanisms was also studied with scanning electron microscopy and energy dispersive X-ray spectroscopy.

  2. Characterization of embedded fiber optic strain sensors into metallic structures via ultrasonic additive manufacturing

    NASA Astrophysics Data System (ADS)

    Schomer, John J.; Hehr, Adam J.; Dapino, Marcelo J.

    2016-04-01

    Fiber Bragg Grating (FBG) sensors measure deviation in a reflected wavelength of light to detect in-situ strain. These sensors are immune to electromagnetic interference, and the inclusion of multiple FBGs on the same fiber allows for a seamlessly integrated sensing network. FBGs are attractive for embedded sensing in aerospace applications due to their small noninvasive size and prospect of constant, real-time nondestructive evaluation. In this study, FBG sensors are embedded in aluminum 6061 via ultrasonic additive manufacturing (UAM), a rapid prototyping process that uses high power ultrasonic vibrations to weld similar and dissimilar metal foils together. UAM was chosen due to the desire to embed FBG sensors at low temperatures, a requirement that excludes other additive processes such as selective laser sintering or fusion deposition modeling. In this paper, the embedded FBGs are characterized in terms of birefringence losses, post embedding strain shifts, consolidation quality, and strain sensing performance. Sensors embedded into an ASTM test piece are compared against an exterior surface mounted foil strain gage at both room and elevated temperatures using cyclic tensile tests.

  3. Comparative Protein Structure Modeling Using MODELLER.

    PubMed

    Webb, Benjamin; Sali, Andrej

    2016-01-01

    Comparative protein structure modeling predicts the three-dimensional structure of a given protein sequence (target) based primarily on its alignment to one or more proteins of known structure (templates). The prediction process consists of fold assignment, target-template alignment, model building, and model evaluation. This unit describes how to calculate comparative models using the program MODELLER and how to use the ModBase database of such models, and discusses all four steps of comparative modeling, frequently observed errors, and some applications. Modeling lactate dehydrogenase from Trichomonas vaginalis (TvLDH) is described as an example. The download and installation of the MODELLER software is also described. © 2016 by John Wiley & Sons, Inc. PMID:27322406

  4. Comparative Protein Structure Modeling Using MODELLER.

    PubMed

    Webb, Benjamin; Sali, Andrej

    2016-06-20

    Comparative protein structure modeling predicts the three-dimensional structure of a given protein sequence (target) based primarily on its alignment to one or more proteins of known structure (templates). The prediction process consists of fold assignment, target-template alignment, model building, and model evaluation. This unit describes how to calculate comparative models using the program MODELLER and how to use the ModBase database of such models, and discusses all four steps of comparative modeling, frequently observed errors, and some applications. Modeling lactate dehydrogenase from Trichomonas vaginalis (TvLDH) is described as an example. The download and installation of the MODELLER software is also described. © 2016 by John Wiley & Sons, Inc.

  5. An extended cure model and model selection.

    PubMed

    Peng, Yingwei; Xu, Jianfeng

    2012-04-01

    We propose a novel interpretation for a recently proposed Box-Cox transformation cure model, which leads to a natural extension of the cure model. Based on the extended model, we consider an important issue of model selection between the mixture cure model and the bounded cumulative hazard cure model via the likelihood ratio test, score test and Akaike's Information Criterion (AIC). Our empirical study shows that AIC is informative and both the score test and the likelihood ratio test have adequate power to differentiate between the mixture cure model and the bounded cumulative hazard cure model when the sample size is large. We apply the tests and AIC methods to leukemia and colon cancer data to examine the appropriateness of the cure models considered for them in the literature.

  6. Model selection for logistic regression models

    NASA Astrophysics Data System (ADS)

    Duller, Christine

    2012-09-01

    Model selection for logistic regression models decides which of some given potential regressors have an effect and hence should be included in the final model. The second interesting question is whether a certain factor is heterogeneous among some subsets, i.e. whether the model should include a random intercept or not. In this paper these questions will be answered with classical as well as with Bayesian methods. The application show some results of recent research projects in medicine and business administration.

  7. Multilevel Model Prediction

    ERIC Educational Resources Information Center

    Frees, Edward W.; Kim, Jee-Seon

    2006-01-01

    Multilevel models are proven tools in social research for modeling complex, hierarchical systems. In multilevel modeling, statistical inference is based largely on quantification of random variables. This paper distinguishes among three types of random variables in multilevel modeling--model disturbances, random coefficients, and future response…

  8. "Bohr's Atomic Model."

    ERIC Educational Resources Information Center

    Willden, Jeff

    2001-01-01

    "Bohr's Atomic Model" is a small interactive multimedia program that introduces the viewer to a simplified model of the atom. This interactive simulation lets students build an atom using an atomic construction set. The underlying design methodology for "Bohr's Atomic Model" is model-centered instruction, which means the central model of the…

  9. Sand-box modelling

    SciTech Connect

    Avery, P.

    1983-01-01

    As the result of an enquiry into BHRA's physical-reservoir-modelling experience, the use of sand box models was investigated. The type of model was considered a possible means of confirmation of a numerical model. The problem facing the numerical model user was comparing the performance of inclined or horizontal oil wells with that of the conventional vertical well.

  10. Solicited abstract: Global hydrological modeling and models

    NASA Astrophysics Data System (ADS)

    Xu, Chong-Yu

    2010-05-01

    The origins of rainfall-runoff modeling in the broad sense can be found in the middle of the 19th century arising in response to three types of engineering problems: (1) urban sewer design, (2) land reclamation drainage systems design, and (3) reservoir spillway design. Since then numerous empirical, conceptual and physically-based models are developed including event based models using unit hydrograph concept, Nash's linear reservoir models, HBV model, TOPMODEL, SHE model, etc. From the late 1980s, the evolution of global and continental-scale hydrology has placed new demands on hydrologic modellers. The macro-scale hydrological (global and regional scale) models were developed on the basis of the following motivations (Arenll, 1999). First, for a variety of operational and planning purposes, water resource managers responsible for large regions need to estimate the spatial variability of resources over large areas, at a spatial resolution finer than can be provided by observed data alone. Second, hydrologists and water managers are interested in the effects of land-use and climate variability and change over a large geographic domain. Third, there is an increasing need of using hydrologic models as a base to estimate point and non-point sources of pollution loading to streams. Fourth, hydrologists and atmospheric modellers have perceived weaknesses in the representation of hydrological processes in regional and global climate models, and developed global hydrological models to overcome the weaknesses of global climate models. Considerable progress in the development and application of global hydrological models has been achieved to date, however, large uncertainties still exist considering the model structure including large scale flow routing, parameterization, input data, etc. This presentation will focus on the global hydrological models, and the discussion includes (1) types of global hydrological models, (2) procedure of global hydrological model development

  11. Bohr model as an algebraic collective model

    SciTech Connect

    Rowe, D. J.; Welsh, T. A.; Caprio, M. A.

    2009-05-15

    Developments and applications are presented of an algebraic version of Bohr's collective model. Illustrative examples show that fully converged calculations can be performed quickly and easily for a large range of Hamiltonians. As a result, the Bohr model becomes an effective tool in the analysis of experimental data. The examples are chosen both to confirm the reliability of the algebraic collective model and to show the diversity of results that can be obtained by its use. The focus of the paper is to facilitate identification of the limitations of the Bohr model with a view to developing more realistic, computationally tractable models.

  12. 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

  13. Geologic Framework Model Analysis Model Report

    SciTech Connect

    R. Clayton

    2000-12-19

    The purpose of this report is to document the Geologic Framework Model (GFM), Version 3.1 (GFM3.1) with regard to data input, modeling methods, assumptions, uncertainties, limitations, and validation of the model results, qualification status of the model, and the differences between Version 3.1 and previous versions. The GFM represents a three-dimensional interpretation of the stratigraphy and structural features of the location of the potential Yucca Mountain radioactive waste repository. The GFM encompasses an area of 65 square miles (170 square kilometers) and a volume of 185 cubic miles (771 cubic kilometers). The boundaries of the GFM were chosen to encompass the most widely distributed set of exploratory boreholes (the Water Table or WT series) and to provide a geologic framework over the area of interest for hydrologic flow and radionuclide transport modeling through the unsaturated zone (UZ). The depth of the model is constrained by the inferred depth of the Tertiary-Paleozoic unconformity. The GFM was constructed from geologic map and borehole data. Additional information from measured stratigraphy sections, gravity profiles, and seismic profiles was also considered. This interim change notice (ICN) was prepared in accordance with the Technical Work Plan for the Integrated Site Model Process Model Report Revision 01 (CRWMS M&O 2000). The constraints, caveats, and limitations associated with this model are discussed in the appropriate text sections that follow. The GFM is one component of the Integrated Site Model (ISM) (Figure l), which has been developed to provide a consistent volumetric portrayal of the rock layers, rock properties, and mineralogy of the Yucca Mountain site. The ISM consists of three components: (1) Geologic Framework Model (GFM); (2) Rock Properties Model (RPM); and (3) Mineralogic Model (MM). The ISM merges the detailed project stratigraphy into model stratigraphic units that are most useful for the primary downstream models and the

  14. Models of Magnetism.

    ERIC Educational Resources Information Center

    Borges, A. Tarciso; Gilbert, John K.

    1998-01-01

    Investigates the mental models that people construct about magnetic phenomena. Involves students, physics teachers, engineers, and practitioners. Proposes five models following a progression from simple description to a field model. Contains 28 references. (DDR)

  15. Educating with Aircraft Models

    ERIC Educational Resources Information Center

    Steele, Hobie

    1976-01-01

    Described is utilization of aircraft models, model aircraft clubs, and model aircraft magazines to promote student interest in aerospace education. The addresses for clubs and magazines are included. (SL)

  16. Forest succession models

    SciTech Connect

    Shugart, H.H. Jr.; West, D.C.

    1980-05-01

    Studies in succession attempt to determine the changes in species composition and other ecosystem attributes expected to occur over periods of time. Mathematical models developed in forestry and ecology to study ecological succession are reviewed. Tree models, gap models and forest models are discussed. Model validation or testing procedures are described. Model applications can involve evaluating large-scale and long-term changes in the ambient levels of pollutants and assessing the effects of climate change on the environment. (RJC)

  17. Modeling of geothermal systems

    SciTech Connect

    Bodvarsson, G.S.; Pruess, K.; Lippmann, M.J.

    1985-03-01

    During the last decade the use of numerical modeling for geothermal resource evaluation has grown significantly, and new modeling approaches have been developed. In this paper we present a summary of the present status in numerical modeling of geothermal systems, emphasizing recent developments. Different modeling approaches are described and their applicability discussed. The various modeling tasks, including natural-state, exploitation, injection, multi-component and subsidence modeling, are illustrated with geothermal field examples. 99 refs., 14 figs.

  18. Generalized smooth models

    SciTech Connect

    Glosup, J.

    1992-07-23

    The class of gene linear models is extended to develop a class of nonparametric regression models known as generalized smooth models. The technique of local scoring is used to estimate a generalized smooth model and the estimation procedure based on locally weighted regression is shown to produce local likelihood estimates. The asymptotically correct distribution of the deviance difference is derived and its use in comparing the fits of generalized linear models and generalized smooth models is illustrated. The relationship between generalized smooth models and generalized additive models is discussed, also.

  19. ROCK PROPERTIES MODEL ANALYSIS MODEL REPORT

    SciTech Connect

    Clinton Lum

    2002-02-04

    The purpose of this Analysis and Model Report (AMR) is to document Rock Properties Model (RPM) 3.1 with regard to input data, model methods, assumptions, uncertainties and limitations of model results, and qualification status of the model. The report also documents the differences between the current and previous versions and validation of the model. The rock properties models are intended principally for use as input to numerical physical-process modeling, such as of ground-water flow and/or radionuclide transport. The constraints, caveats, and limitations associated with this model are discussed in the appropriate text sections that follow. This work was conducted in accordance with the following planning documents: WA-0344, ''3-D Rock Properties Modeling for FY 1998'' (SNL 1997, WA-0358), ''3-D Rock Properties Modeling for FY 1999'' (SNL 1999), and the technical development plan, Rock Properties Model Version 3.1, (CRWMS M&O 1999c). The Interim Change Notice (ICNs), ICN 02 and ICN 03, of this AMR were prepared as part of activities being conducted under the Technical Work Plan, TWP-NBS-GS-000003, ''Technical Work Plan for the Integrated Site Model, Process Model Report, Revision 01'' (CRWMS M&O 2000b). The purpose of ICN 03 is to record changes in data input status due to data qualification and verification activities. These work plans describe the scope, objectives, tasks, methodology, and implementing procedures for model construction. The constraints, caveats, and limitations associated with this model are discussed in the appropriate text sections that follow. The work scope for this activity consists of the following: (1) Conversion of the input data (laboratory measured porosity data, x-ray diffraction mineralogy, petrophysical calculations of bound water, and petrophysical calculations of porosity) for each borehole into stratigraphic coordinates; (2) Re-sampling and merging of data sets; (3) Development of geostatistical simulations of porosity; (4

  20. Scaled models, scaled frequencies, and model fitting

    NASA Astrophysics Data System (ADS)

    Roxburgh, Ian W.

    2015-12-01

    I show that given a model star of mass M, radius R, and density profile ρ(x) [x = r/R], there exists a two parameter family of models with masses Mk, radii Rk, density profile ρk(x) = λρ(x) and frequencies νknℓ = λ1/2νnℓ, where λ,Rk/RA are scaling factors. These models have different internal structures, but all have the same value of separation ratios calculated at given radial orders n, and all exactly satisfy a frequency matching algorithm with an offset function determined as part of the fitting procedure. But they do not satisfy ratio matching at given frequencies nor phase shift matching. This illustrates that erroneous results may be obtained when model fitting with ratios at given n values or frequency matching. I give examples from scaled models and from non scaled evolutionary models.

  1. Simulation of the Lower and Upper Atmosphere Interconnection

    NASA Astrophysics Data System (ADS)

    Beloushko, Konstantin

    Attempt to develop the united numerical model of the Earth’s atmosphere is undertaken. Purpose of the project is development of the general methodologies and technologies of coupling of models with use of the so-called frame approach [1]. As a basis to this metamodel was taken Upper Atmosphere Model (UAM) [2, 3]. UAM is for today the advanced and perspective Russian model of the upper atmosphere qualitatively comparable to foreign analogues and in a number of aspects surpassing them (on a covered range of heights, for example, from 60 up to 100000 km). As model of the lower atmosphere the General circulation model of atmosphere and ocean by Institute of Numerical Mathematics of the Russian Academy of Science (INM RAS, Moscow) is chosen. This model is equal to quality and competes with modern foreign forecasting models of weather and climate [4]. Coupling of UAM and INM RAS models will allow not only to develop united model of atmosphere of the Earth, but also thus to remove the uncertainty, connected with definition the upper boundary conditions in weather area and lower boundary conditions in upper atmosphere. As a result of named problem analysis the following algorithm for coupling of models is offered: on range of coverage by both models an interval of heights (60-90 km) the iterative exchange of boundary conditions performed. Results of some joined simulations on the basis of model of upper atmosphere UAM and model of general circulation of INM RAS are presented and discussed. Author thanks for discussions and giving model data by A.A. Namgaladze (MSTU, Murmansk) and E.M. Volodin (INM, Moscow). References begin{enumerate} Beloushko K. E. Simulation of the Coupling of the Upper and Lower Atmosphere // Russian Journal of Physical Chemistry B, 2013, Vol. 7, № 6, pp. 783-787. DOI: 10.1134/S199079311305014X Namgaladze A.A., Korenkov Yu.N., Klimenko V.V., Karpov I.V., Bessarab F.S., Surotkin V.A., Gluschenko T.A., Naumova N.M. Global model of the thermosphere

  2. Better models are more effectively connected models

    NASA Astrophysics Data System (ADS)

    Nunes, João Pedro; Bielders, Charles; Darboux, Frederic; Fiener, Peter; Finger, David; Turnbull-Lloyd, Laura; Wainwright, John

    2016-04-01

    The concept of hydrologic and geomorphologic connectivity describes the processes and pathways which link sources (e.g. rainfall, snow and ice melt, springs, eroded areas and barren lands) to accumulation areas (e.g. foot slopes, streams, aquifers, reservoirs), and the spatial variations thereof. There are many examples of hydrological and sediment connectivity on a watershed scale; in consequence, a process-based understanding of connectivity is crucial to help managers understand their systems and adopt adequate measures for flood prevention, pollution mitigation and soil protection, among others. Modelling is often used as a tool to understand and predict fluxes within a catchment by complementing observations with model results. Catchment models should therefore be able to reproduce the linkages, and thus the connectivity of water and sediment fluxes within the systems under simulation. In modelling, a high level of spatial and temporal detail is desirable to ensure taking into account a maximum number of components, which then enables connectivity to emerge from the simulated structures and functions. However, computational constraints and, in many cases, lack of data prevent the representation of all relevant processes and spatial/temporal variability in most models. In most cases, therefore, the level of detail selected for modelling is too coarse to represent the system in a way in which connectivity can emerge; a problem which can be circumvented by representing fine-scale structures and processes within coarser scale models using a variety of approaches. This poster focuses on the results of ongoing discussions on modelling connectivity held during several workshops within COST Action Connecteur. It assesses the current state of the art of incorporating the concept of connectivity in hydrological and sediment models, as well as the attitudes of modellers towards this issue. The discussion will focus on the different approaches through which connectivity

  3. Biosphere Model Report

    SciTech Connect

    D. W. Wu

    2003-07-16

    The purpose of this report is to document the biosphere model, the Environmental Radiation Model for Yucca Mountain, Nevada (ERMYN), which describes radionuclide transport processes in the biosphere and associated human exposure that may arise as the result of radionuclide release from the geologic repository at Yucca Mountain. The biosphere model is one of the process models that support the Yucca Mountain Project (YMP) Total System Performance Assessment (TSPA) for the license application (LA), the TSPA-LA. The ERMYN model provides the capability of performing human radiation dose assessments. This report documents the biosphere model, which includes: (1) Describing the reference biosphere, human receptor, exposure scenarios, and primary radionuclides for each exposure scenario (Section 6.1); (2) Developing a biosphere conceptual model using site-specific features, events, and processes (FEPs), the reference biosphere, the human receptor, and assumptions (Section 6.2 and Section 6.3); (3) Building a mathematical model using the biosphere conceptual model and published biosphere models (Sections 6.4 and 6.5); (4) Summarizing input parameters for the mathematical model, including the uncertainty associated with input values (Section 6.6); (5) Identifying improvements in the ERMYN model compared with the model used in previous biosphere modeling (Section 6.7); (6) Constructing an ERMYN implementation tool (model) based on the biosphere mathematical model using GoldSim stochastic simulation software (Sections 6.8 and 6.9); (7) Verifying the ERMYN model by comparing output from the software with hand calculations to ensure that the GoldSim implementation is correct (Section 6.10); and (8) Validating the ERMYN model by corroborating it with published biosphere models; comparing conceptual models, mathematical models, and numerical results (Section 7).

  4. Biosphere Model Report

    SciTech Connect

    M. A. Wasiolek

    2003-10-27

    The purpose of this report is to document the biosphere model, the Environmental Radiation Model for Yucca Mountain, Nevada (ERMYN), which describes radionuclide transport processes in the biosphere and associated human exposure that may arise as the result of radionuclide release from the geologic repository at Yucca Mountain. The biosphere model is one of the process models that support the Yucca Mountain Project (YMP) Total System Performance Assessment (TSPA) for the license application (LA), the TSPA-LA. The ERMYN model provides the capability of performing human radiation dose assessments. This report documents the biosphere model, which includes: (1) Describing the reference biosphere, human receptor, exposure scenarios, and primary radionuclides for each exposure scenario (Section 6.1); (2) Developing a biosphere conceptual model using site-specific features, events, and processes (FEPs), the reference biosphere, the human receptor, and assumptions (Section 6.2 and Section 6.3); (3) Building a mathematical model using the biosphere conceptual model and published biosphere models (Sections 6.4 and 6.5); (4) Summarizing input parameters for the mathematical model, including the uncertainty associated with input values (Section 6.6); (5) Identifying improvements in the ERMYN model compared with the model used in previous biosphere modeling (Section 6.7); (6) Constructing an ERMYN implementation tool (model) based on the biosphere mathematical model using GoldSim stochastic simulation software (Sections 6.8 and 6.9); (7) Verifying the ERMYN model by comparing output from the software with hand calculations to ensure that the GoldSim implementation is correct (Section 6.10); and (8) Validating the ERMYN model by corroborating it with published biosphere models; comparing conceptual models, mathematical models, and numerical results (Section 7).

  5. Qualitative Student Models.

    ERIC Educational Resources Information Center

    Clancey, William J.

    The concept of a qualitative model is used as the focus of this review of qualitative student models in order to compare alternative computational models and to contrast domain requirements. The report is divided into eight sections: (1) Origins and Goals (adaptive instruction, qualitative models of processes, components of an artificial…

  6. Biomass Scenario Model

    SciTech Connect

    2015-09-01

    The Biomass Scenario Model (BSM) is a unique, carefully validated, state-of-the-art dynamic model of the domestic biofuels supply chain which explicitly focuses on policy issues, their feasibility, and potential side effects. It integrates resource availability, physical/technological/economic constraints, behavior, and policy. The model uses a system dynamics simulation (not optimization) to model dynamic interactions across the supply chain.

  7. The Instrumental Model

    ERIC Educational Resources Information Center

    Yeates, Devin Rodney

    2011-01-01

    The goal of this dissertation is to enable better predictive models by engaging raw experimental data through the Instrumental Model. The Instrumental Model captures the protocols and procedures of experimental data analysis. The approach is formalized by encoding the Instrumental Model in an XML record. Decoupling the raw experimental data from…

  8. AIDS Epidemiological models

    NASA Astrophysics Data System (ADS)

    Rahmani, Fouad Lazhar

    2010-11-01

    The aim of this paper is to present mathematical modelling of the spread of infection in the context of the transmission of the human immunodeficiency virus (HIV) and the acquired immune deficiency syndrome (AIDS). These models are based in part on the models suggested in the field of th AIDS mathematical modelling as reported by ISHAM [6].

  9. Enclosure fire dynamics model

    NASA Technical Reports Server (NTRS)

    Bellan, J.

    1979-01-01

    A practical situation of an enclosure fire is presented and why the need for a fire dynamic model is addressed. The difficulties in establishing a model are discussed, along with a brief review of enclosure fire models available. The approximation of the practical situation and the model developed are presented.

  10. Modeling for Understanding.

    ERIC Educational Resources Information Center

    Klopfer, Eric; Colella, Vanessa

    This paper focuses on one method used to introduce model design and creation using StarLogo to a group of high school teachers. Teachers with model-building skills can easily customize modeling environments for their classes. More importantly, model building can enable teachers to approach their curricula from a more holistic perspective, as well…

  11. Calibrated Properties Model

    SciTech Connect

    C.F. Ahlers, H.H. Liu

    2001-12-18

    The purpose of this Analysis/Model Report (AMR) is to document the Calibrated Properties Model that provides calibrated parameter sets for unsaturated zone (UZ) flow and transport process models for the Yucca Mountain Site Characterization Project (YMP). This work was performed in accordance with the AMR Development Plan for U0035 Calibrated Properties Model REV00 (CRWMS M&O 1999c). These calibrated property sets include matrix and fracture parameters for the UZ Flow and Transport Model (UZ Model), drift seepage models, drift-scale and mountain-scale coupled-processes models, and Total System Performance Assessment (TSPA) models as well as Performance Assessment (PA) and other participating national laboratories and government agencies. These process models provide the necessary framework to test conceptual hypotheses of flow and transport at different scales and predict flow and transport behavior under a variety of climatic and thermal-loading conditions.

  12. Calibrated Properties Model

    SciTech Connect

    C. Ahlers; H. Liu

    2000-03-12

    The purpose of this Analysis/Model Report (AMR) is to document the Calibrated Properties Model that provides calibrated parameter sets for unsaturated zone (UZ) flow and transport process models for the Yucca Mountain Site Characterization Project (YMP). This work was performed in accordance with the ''AMR Development Plan for U0035 Calibrated Properties Model REV00. These calibrated property sets include matrix and fracture parameters for the UZ Flow and Transport Model (UZ Model), drift seepage models, drift-scale and mountain-scale coupled-processes models, and Total System Performance Assessment (TSPA) models as well as Performance Assessment (PA) and other participating national laboratories and government agencies. These process models provide the necessary framework to test conceptual hypotheses of flow and transport at different scales and predict flow and transport behavior under a variety of climatic and thermal-loading conditions.

  13. Power weighted L p -inequalities for Laguerre-Riesz transforms

    NASA Astrophysics Data System (ADS)

    Harboure, Eleonor; Segovia, Carlos; Torrea, José L.; Viviani, Beatriz

    2008-10-01

    In this paper we give a complete description of the power weighted inequalities, of strong, weak and restricted weak type for the pair of Riesz transforms associated with the Laguerre function system \\{mathcal{L}_k^{α}\\}, for any given α>-1. We achieve these results by a careful estimate of the kernels: near the diagonal we show that they are local Calderón-Zygmund operators while in the complement they are majorized by Hardy type operators and the maximal heat-diffusion operator. We also show that in all the cases our results are sharp.

  14. Introduction to Adjoint Models

    NASA Technical Reports Server (NTRS)

    Errico, Ronald M.

    2015-01-01

    In this lecture, some fundamentals of adjoint models will be described. This includes a basic derivation of tangent linear and corresponding adjoint models from a parent nonlinear model, the interpretation of adjoint-derived sensitivity fields, a description of methods of automatic differentiation, and the use of adjoint models to solve various optimization problems, including singular vectors. Concluding remarks will attempt to correct common misconceptions about adjoint models and their utilization.

  15. Stable models of superacceleration

    SciTech Connect

    Kaplinghat, Manoj; Rajaraman, Arvind

    2007-05-15

    We discuss an instability in a large class of models where dark energy is coupled to matter. In these models the mass of the scalar field is much larger than the expansion rate of the Universe. We find models in which this instability is absent, and show that these models generically predict an apparent equation of state for dark energy smaller than -1, i.e., superacceleration. These models have no acausal behavior or ghosts.

  16. Identification and influence of spatial outliers in air quality measurements

    NASA Astrophysics Data System (ADS)

    O'Leary, B. F.; Lemke, L. D.

    2015-12-01

    The heterogeneous nature of urban air complicates the analysis of spatial and temporal variability in air quality measurements. Evaluation of potentially inaccurate measurements (i.e., outliers) poses particularly difficult challenges in extensive air quality datasets with multiple measurements distributed in time and space. This study investigated the identification and impact of outliers in measurements of NO­2, BTEX, PM2.5, and PM10 in the contiguous Detroit, Michigan, USA and Windsor, Ontario, Canada international airshed. Measurements were taken at 100 locations during September 2008 and June 2009 and modeled at a 300m by 300m scale resolution. The objective was to determine if outliers were present and, if so, to quantify the magnitude of their impact on modeled spatial pollution distributions. The study built upon previous investigations by the Geospatial Determinants of Health Outcomes Consortium that examined relationships between air pollutant distributions and asthma exacerbations in the Detroit and Windsor airshed. Four independent approaches were initially employed to identify potential outliers: boxplots, variogram clouds, difference maps, and the Local Moran's I statistic. Potential outliers were subsequently reevaluated for consistency among methods and individually assessed to select a final set of outliers. The impact of excluding individual outliers was subsequently determined by revising the spatially variable air pollution models and recalculating associations between air contaminant concentrations and asthma exacerbations in Detroit and Windsor in 2008. For the pollutants examined, revised associations revealed weaker correlations with spatial outliers removed. Nevertheless, the approach employed improves the model integrity by increasing our understanding of the spatial variability of air pollution in the built environment and providing additional insights into the association between acute asthma exacerbations and air pollution.

  17. WASP TRANSPORT MODELING AND WASP ECOLOGICAL MODELING

    EPA Science Inventory

    A combination of lectures, demonstrations, and hands-on excercises will be used to introduce pollutant transport modeling with the U.S. EPA's general water quality model, WASP (Water Quality Analysis Simulation Program). WASP features include a user-friendly Windows-based interfa...

  18. Multiple model inference.

    SciTech Connect

    Swiler, Laura Painton; Urbina, Angel

    2010-07-01

    This paper compares three approaches for model selection: classical least squares methods, information theoretic criteria, and Bayesian approaches. Least squares methods are not model selection methods although one can select the model that yields the smallest sum-of-squared error function. Information theoretic approaches balance overfitting with model accuracy by incorporating terms that penalize more parameters with a log-likelihood term to reflect goodness of fit. Bayesian model selection involves calculating the posterior probability that each model is correct, given experimental data and prior probabilities that each model is correct. As part of this calculation, one often calibrates the parameters of each model and this is included in the Bayesian calculations. Our approach is demonstrated on a structural dynamics example with models for energy dissipation and peak force across a bolted joint. The three approaches are compared and the influence of the log-likelihood term in all approaches is discussed.

  19. Model Validation Status Review

    SciTech Connect

    E.L. Hardin

    2001-11-28

    The primary objective for the Model Validation Status Review was to perform a one-time evaluation of model validation associated with the analysis/model reports (AMRs) containing model input to total-system performance assessment (TSPA) for the Yucca Mountain site recommendation (SR). This review was performed in response to Corrective Action Request BSC-01-C-01 (Clark 2001, Krisha 2001) pursuant to Quality Assurance review findings of an adverse trend in model validation deficiency. The review findings in this report provide the following information which defines the extent of model validation deficiency and the corrective action needed: (1) AMRs that contain or support models are identified, and conversely, for each model the supporting documentation is identified. (2) The use for each model is determined based on whether the output is used directly for TSPA-SR, or for screening (exclusion) of features, events, and processes (FEPs), and the nature of the model output. (3) Two approaches are used to evaluate the extent to which the validation for each model is compliant with AP-3.10Q (Analyses and Models). The approaches differ in regard to whether model validation is achieved within individual AMRs as originally intended, or whether model validation could be readily achieved by incorporating information from other sources. (4) Recommendations are presented for changes to the AMRs, and additional model development activities or data collection, that will remedy model validation review findings, in support of licensing activities. The Model Validation Status Review emphasized those AMRs that support TSPA-SR (CRWMS M&O 2000bl and 2000bm). A series of workshops and teleconferences was held to discuss and integrate the review findings. The review encompassed 125 AMRs (Table 1) plus certain other supporting documents and data needed to assess model validity. The AMRs were grouped in 21 model areas representing the modeling of processes affecting the natural and

  20. Trapped Radiation Model Uncertainties: Model-Data and Model-Model Comparisons

    NASA Technical Reports Server (NTRS)

    Armstrong, T. W.; Colborn, B. L.

    2000-01-01

    The standard AP8 and AE8 models for predicting trapped proton and electron environments have been compared with several sets of flight data to evaluate model uncertainties. Model comparisons are made with flux and dose measurements made on various U.S. low-Earth orbit satellites (APEX, CRRES, DMSP, LDEF, NOAA) and Space Shuttle flights, on Russian satellites (Photon-8, Cosmos-1887, Cosmos-2044), and on the Russian Mir Space Station. This report gives the details of the model-data comparisons-summary results in terms of empirical model uncertainty factors that can be applied for spacecraft design applications are given in a combination report. The results of model-model comparisons are also presented from standard AP8 and AE8 model predictions compared with the European Space Agency versions of AP8 and AE8 and with Russian-trapped radiation models.

  1. Trapped Radiation Model Uncertainties: Model-Data and Model-Model Comparisons

    NASA Technical Reports Server (NTRS)

    Armstrong, T. W.; Colborn, B. L.

    2000-01-01

    The standard AP8 and AE8 models for predicting trapped proton and electron environments have been compared with several sets of flight data to evaluate model uncertainties. Model comparisons are made with flux and dose measurements made on various U.S. low-Earth orbit satellites (APEX, CRRES, DMSP. LDEF, NOAA) and Space Shuttle flights, on Russian satellites (Photon-8, Cosmos-1887, Cosmos-2044), and on the Russian Mir space station. This report gives the details of the model-data comparisons -- summary results in terms of empirical model uncertainty factors that can be applied for spacecraft design applications are given in a companion report. The results of model-model comparisons are also presented from standard AP8 and AE8 model predictions compared with the European Space Agency versions of AP8 and AE8 and with Russian trapped radiation models.

  2. Modeling nonstationary longitudinal data.

    PubMed

    Núñez-Antón, V; Zimmerman, D L

    2000-09-01

    An important theme of longitudinal data analysis in the past two decades has been the development and use of explicit parametric models for the data's variance-covariance structure. A variety of these models have been proposed, of which most are second-order stationary. A few are flexible enough to accommodate nonstationarity, i.e., nonconstant variances and/or correlations that are not a function solely of elapsed time between measurements. We review five nonstationary models that we regard as most useful: (1) the unstructured covariance model, (2) unstructured antedependence models, (3) structured antedependence models, (4) autoregressive integrated moving average and similar models, and (5) random coefficients models. We evaluate the relative strengths and limitations of each model, emphasizing when it is inappropriate or unlikely to be useful. We present three examples to illustrate the fitting and comparison of the models and to demonstrate that nonstationary longitudinal data can be modeled effectively and, in some cases, quite parsimoniously. In these examples, the antedependence models generally prove to be superior and the random coefficients models prove to be inferior. We conclude that antedependence models should be given much greater consideration than they have historically received.

  3. Modeling Hydrothermal Mineralization: Fractal or Multifrcatal Models?

    NASA Astrophysics Data System (ADS)

    Cheng, Q.

    2004-05-01

    Hydrothermal mineralization occurs when the natural geo-processes involve the interaction of ore material-carrying hydrothermal fluids with rocks in the earth's crust in a specific geological environment. Mineralization can cause element concentration enrichment or depletion in the country rocks. Local enrichment may form ore body that can be mined for profit at the current economic and technological conditions. To understand the spatial distribution of element concentration enrichment or depletion caused by mineralization in a mineral district is essential for mineral exploration and mineral prediction. Grade-tonnage model and mineral deposits size distribution model are common models used for characterizing mineral deposits. This paper proposes a non-linear mineralization model on the basis of a modified classical igneous differentiation mineralization model to describe the generation of multifractal distribution of element concentration in the country rocks as well as grade-tonnage fractal/multifractal distribution of ore deposits that have been often observed in hydrothermal mineralization. This work may also lead to a singularity model to explain the common properties of mineralization and mineralization-associated geochemical anomaly diversity and the generalized self-similarity of the anomalies. The model has been applied to a case study of mineral deposits prediction and mineral resource assessment in the Abitibi district, northern Ontario, Canada.

  4. Modeling the transition region

    NASA Technical Reports Server (NTRS)

    Singer, Bart A.

    1993-01-01

    The current status of transition-region models is reviewed in this report. To understand modeling problems, various flow features that influence the transition process are discussed first. Then an overview of the different approaches to transition-region modeling is given. This is followed by a detailed discussion of turbulence models and the specific modifications that are needed to predict flows undergoing laminar-turbulent transition. Methods for determining the usefulness of the models are presented, and an outlook for the future of transition-region modeling is suggested.

  5. Ensemble Atmospheric Dispersion Modeling

    SciTech Connect

    Addis, R.P.

    2002-06-24

    Prognostic atmospheric dispersion models are used to generate consequence assessments, which assist decision-makers in the event of a release from a nuclear facility. Differences in the forecast wind fields generated by various meteorological agencies, differences in the transport and diffusion models, as well as differences in the way these models treat the release source term, result in differences in the resulting plumes. Even dispersion models using the same wind fields may produce substantially different plumes. This talk will address how ensemble techniques may be used to enable atmospheric modelers to provide decision-makers with a more realistic understanding of how both the atmosphere and the models behave.

  6. Holographic twin Higgs model.

    PubMed

    Geller, Michael; Telem, Ofri

    2015-05-15

    We present the first realization of a "twin Higgs" model as a holographic composite Higgs model. Uniquely among composite Higgs models, the Higgs potential is protected by a new standard model (SM) singlet elementary "mirror" sector at the sigma model scale f and not by the composite states at m_{KK}, naturally allowing for m_{KK} beyond the LHC reach. As a result, naturalness in our model cannot be constrained by the LHC, but may be probed by precision Higgs measurements at future lepton colliders, and by direct searches for Kaluza-Klein excitations at a 100 TeV collider.

  7. Holographic twin Higgs model.

    PubMed

    Geller, Michael; Telem, Ofri

    2015-05-15

    We present the first realization of a "twin Higgs" model as a holographic composite Higgs model. Uniquely among composite Higgs models, the Higgs potential is protected by a new standard model (SM) singlet elementary "mirror" sector at the sigma model scale f and not by the composite states at m_{KK}, naturally allowing for m_{KK} beyond the LHC reach. As a result, naturalness in our model cannot be constrained by the LHC, but may be probed by precision Higgs measurements at future lepton colliders, and by direct searches for Kaluza-Klein excitations at a 100 TeV collider. PMID:26024160

  8. Modeling worldwide highway networks

    NASA Astrophysics Data System (ADS)

    Villas Boas, Paulino R.; Rodrigues, Francisco A.; da F. Costa, Luciano

    2009-12-01

    This Letter addresses the problem of modeling the highway systems of different countries by using complex networks formalism. More specifically, we compare two traditional geographical models with a modified geometrical network model where paths, rather than edges, are incorporated at each step between the origin and the destination vertices. Optimal configurations of parameters are obtained for each model and used for the comparison. The highway networks of Australia, Brazil, India, and Romania are considered and shown to be properly modeled by the modified geographical model.

  9. Energy-consumption modelling

    SciTech Connect

    Reiter, E.R.

    1980-01-01

    A highly sophisticated and accurate approach is described to compute on an hourly or daily basis the energy consumption for space heating by individual buildings, urban sectors, and whole cities. The need for models and specifically weather-sensitive models, composite models, and space-heating models are discussed. Development of the Colorado State University Model, based on heat-transfer equations and on a heuristic, adaptive, self-organizing computation learning approach, is described. Results of modeling energy consumption by the city of Minneapolis and Cheyenne are given. Some data on energy consumption in individual buildings are included.

  10. Reliability model generator

    NASA Technical Reports Server (NTRS)

    McMann, Catherine M. (Inventor); Cohen, Gerald C. (Inventor)

    1991-01-01

    An improved method and system for automatically generating reliability models for use with a reliability evaluation tool is described. The reliability model generator of the present invention includes means for storing a plurality of low level reliability models which represent the reliability characteristics for low level system components. In addition, the present invention includes means for defining the interconnection of the low level reliability models via a system architecture description. In accordance with the principles of the present invention, a reliability model for the entire system is automatically generated by aggregating the low level reliability models based on the system architecture description.

  11. A future of the model organism model

    PubMed Central

    Rine, Jasper

    2014-01-01

    Changes in technology are fundamentally reframing our concept of what constitutes a model organism. Nevertheless, research advances in the more traditional model organisms have enabled fresh and exciting opportunities for young scientists to establish new careers and offer the hope of comprehensive understanding of fundamental processes in life. New advances in translational research can be expected to heighten the importance of basic research in model organisms and expand opportunities. However, researchers must take special care and implement new resources to enable the newest members of the community to engage fully with the remarkable legacy of information in these fields. PMID:24577733

  12. Develop a Model Component

    NASA Technical Reports Server (NTRS)

    Ensey, Tyler S.

    2013-01-01

    During my internship at NASA, I was a model developer for Ground Support Equipment (GSE). The purpose of a model developer is to develop and unit test model component libraries (fluid, electrical, gas, etc.). The models are designed to simulate software for GSE (Ground Special Power, Crew Access Arm, Cryo, Fire and Leak Detection System, Environmental Control System (ECS), etc. .) before they are implemented into hardware. These models support verifying local control and remote software for End-Item Software Under Test (SUT). The model simulates the physical behavior (function, state, limits and 110) of each end-item and it's dependencies as defined in the Subsystem Interface Table, Software Requirements & Design Specification (SRDS), Ground Integrated Schematic (GIS), and System Mechanical Schematic.(SMS). The software of each specific model component is simulated through MATLAB's Simulink program. The intensiv model development life cycle is a.s follows: Identify source documents; identify model scope; update schedule; preliminary design review; develop model requirements; update model.. scope; update schedule; detailed design review; create/modify library component; implement library components reference; implement subsystem components; develop a test script; run the test script; develop users guide; send model out for peer review; the model is sent out for verifictionlvalidation; if there is empirical data, a validation data package is generated; if there is not empirical data, a verification package is generated; the test results are then reviewed; and finally, the user. requests accreditation, and a statement of accreditation is prepared. Once each component model is reviewed and approved, they are intertwined together into one integrated model. This integrated model is then tested itself, through a test script and autotest, so that it can be concluded that all models work conjointly, for a single purpose. The component I was assigned, specifically, was a

  13. Biosphere Model Report

    SciTech Connect

    D.W. Wu; A.J. Smith

    2004-11-08

    The purpose of this report is to document the biosphere model, the Environmental Radiation Model for Yucca Mountain, Nevada (ERMYN), which describes radionuclide transport processes in the biosphere and associated human exposure that may arise as the result of radionuclide release from the geologic repository at Yucca Mountain. The biosphere model is one of the process models that support the Yucca Mountain Project (YMP) Total System Performance Assessment (TSPA) for the license application (LA), TSPA-LA. The ERMYN provides the capability of performing human radiation dose assessments. This report documents the biosphere model, which includes: (1) Describing the reference biosphere, human receptor, exposure scenarios, and primary radionuclides for each exposure scenario (Section 6.1); (2) Developing a biosphere conceptual model using site-specific features, events, and processes (FEPs) (Section 6.2), the reference biosphere (Section 6.1.1), the human receptor (Section 6.1.2), and approximations (Sections 6.3.1.4 and 6.3.2.4); (3) Building a mathematical model using the biosphere conceptual model (Section 6.3) and published biosphere models (Sections 6.4 and 6.5); (4) Summarizing input parameters for the mathematical model, including the uncertainty associated with input values (Section 6.6); (5) Identifying improvements in the ERMYN compared with the model used in previous biosphere modeling (Section 6.7); (6) Constructing an ERMYN implementation tool (model) based on the biosphere mathematical model using GoldSim stochastic simulation software (Sections 6.8 and 6.9); (7) Verifying the ERMYN by comparing output from the software with hand calculations to ensure that the GoldSim implementation is correct (Section 6.10); (8) Validating the ERMYN by corroborating it with published biosphere models; comparing conceptual models, mathematical models, and numerical results (Section 7).

  14. Does air pollution pose a public health problem for New Zealand?

    PubMed

    Scoggins, Amanda

    2004-02-01

    Air pollution is increasingly documented as a threat to public health and a major focus of regulatory activity in developed and developing countries. Air quality indicators suggest New Zealand has clean air relative to many other countries. However, media releases such as 'Christchurch wood fires pump out deadly smog' and 'Vehicle pollution major killer' have sparked public health concern regarding exposure to ambient air pollution, especially in anticipation of increasing emissions and population growth. Recent evidence is presented on the effects of air quality on health, which has been aided by the application of urban airshed models and Geographic Information Systems (GIS). Future directions for research into the effects of air quality on health in New Zealand are discussed, including a national ambient air quality management project: HAPINZ--Health and Air Pollution in New Zealand. PMID:15108741

  15. Does air pollution pose a public health problem for New Zealand?

    PubMed

    Scoggins, Amanda

    2004-02-01

    Air pollution is increasingly documented as a threat to public health and a major focus of regulatory activity in developed and developing countries. Air quality indicators suggest New Zealand has clean air relative to many other countries. However, media releases such as 'Christchurch wood fires pump out deadly smog' and 'Vehicle pollution major killer' have sparked public health concern regarding exposure to ambient air pollution, especially in anticipation of increasing emissions and population growth. Recent evidence is presented on the effects of air quality on health, which has been aided by the application of urban airshed models and Geographic Information Systems (GIS). Future directions for research into the effects of air quality on health in New Zealand are discussed, including a national ambient air quality management project: HAPINZ--Health and Air Pollution in New Zealand.

  16. Aerosol Modeling for the Global Model Initiative

    NASA Technical Reports Server (NTRS)

    Weisenstein, Debra K.; Ko, Malcolm K. W.

    2001-01-01

    The goal of this project is to develop an aerosol module to be used within the framework of the Global Modeling Initiative (GMI). The model development work will be preformed jointly by the University of Michigan and AER, using existing aerosol models at the two institutions as starting points. The GMI aerosol model will be tested, evaluated against observations, and then applied to assessment of the effects of aircraft sulfur emissions as needed by the NASA Subsonic Assessment in 2001. The work includes the following tasks: 1. Implementation of the sulfur cycle within GMI, including sources, sinks, and aqueous conversion of sulfur. Aerosol modules will be added as they are developed and the GMI schedule permits. 2. Addition of aerosol types other than sulfate particles, including dust, soot, organic carbon, and black carbon. 3. Development of new and more efficient parameterizations for treating sulfate aerosol nucleation, condensation, and coagulation among different particle sizes and types.

  17. Nonlinear Modeling by Assembling Piecewise Linear Models

    NASA Technical Reports Server (NTRS)

    Yao, Weigang; Liou, Meng-Sing

    2013-01-01

    To preserve nonlinearity of a full order system over a parameters range of interest, we propose a simple modeling approach by assembling a set of piecewise local solutions, including the first-order Taylor series terms expanded about some sampling states. The work by Rewienski and White inspired our use of piecewise linear local solutions. The assembly of these local approximations is accomplished by assigning nonlinear weights, through radial basis functions in this study. The efficacy of the proposed procedure is validated for a two-dimensional airfoil moving at different Mach numbers and pitching motions, under which the flow exhibits prominent nonlinear behaviors. All results confirm that our nonlinear model is accurate and stable for predicting not only aerodynamic forces but also detailed flowfields. Moreover, the model is robustness-accurate for inputs considerably different from the base trajectory in form and magnitude. This modeling preserves nonlinearity of the problems considered in a rather simple and accurate manner.

  18. Aggregation in ecosystem models and model stability

    NASA Astrophysics Data System (ADS)

    Giricheva, Evgeniya

    2015-05-01

    Using a multimodal approach to research ecosystems improves usage of available information on an object. This study presents several models of the Bering Sea ecosystem. The ecosystem is considered as a closed object, that is, the influence of the environment is not provided. We then add the links with the external medium in the models. The models differ in terms of the degree and method of grouping components. Our method is based on the differences in habitat and food source of groups, which allows us to determine the grouping of species with a greater effect on system dynamics. In particular, we determine whether benthic fish aggregation or pelagic fish aggregation can change the consumption structure of some groups of species, and consequently, the behavior of the entire model system.

  19. PREDICTIVE MODELS. Enhanced Oil Recovery Model

    SciTech Connect

    Ray, R.M.

    1992-02-26

    PREDICTIVE MODELS is a collection of five models - CFPM, CO2PM, ICPM, PFPM, and SFPM - used in the 1982-1984 National Petroleum Council study of enhanced oil recovery (EOR) potential. Each pertains to a specific EOR process designed to squeeze additional oil from aging or spent oil fields. The processes are: 1 chemical flooding, where soap-like surfactants are injected into the reservoir to wash out the oil; 2 carbon dioxide miscible flooding, where carbon dioxide mixes with the lighter hydrocarbons making the oil easier to displace; 3 in-situ combustion, which uses the heat from burning some of the underground oil to thin the product; 4 polymer flooding, where thick, cohesive material is pumped into a reservoir to push the oil through the underground rock; and 5 steamflood, where pressurized steam is injected underground to thin the oil. CFPM, the Chemical Flood Predictive Model, models micellar (surfactant)-polymer floods in reservoirs, which have been previously waterflooded to residual oil saturation. Thus, only true tertiary floods are considered. An option allows a rough estimate of oil recovery by caustic or caustic-polymer processes. CO2PM, the Carbon Dioxide miscible flooding Predictive Model, is applicable to both secondary (mobile oil) and tertiary (residual oil) floods, and to either continuous CO2 injection or water-alternating gas processes. ICPM, the In-situ Combustion Predictive Model, computes the recovery and profitability of an in-situ combustion project from generalized performance predictive algorithms. PFPM, the Polymer Flood Predictive Model, is switch-selectable for either polymer or waterflooding, and an option allows the calculation of the incremental oil recovery and economics of polymer relative to waterflooding. SFPM, the Steamflood Predictive Model, is applicable to the steam drive process, but not to cyclic steam injection (steam soak) processes.

  20. Modeling EERE deployment programs

    SciTech Connect

    Cort, K. A.; Hostick, D. J.; Belzer, D. B.; Livingston, O. V.

    2007-11-01

    The purpose of the project was to identify and characterize the modeling of deployment programs within the EERE Technology Development (TD) programs, address possible improvements to the modeling process, and note gaps in knowledge for future research.

  1. Bounding species distribution models

    USGS Publications Warehouse

    Stohlgren, T.J.; Jarnevich, C.S.; Esaias, W.E.; Morisette, J.T.

    2011-01-01

    Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS) might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for "clamping" model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART) and maximum entropy (Maxent) models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used. ?? 2011 Current Zoology.

  2. Bounding Species Distribution Models

    NASA Technical Reports Server (NTRS)

    Stohlgren, Thomas J.; Jarnevich, Cahterine S.; Morisette, Jeffrey T.; Esaias, Wayne E.

    2011-01-01

    Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS) might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for "clamping" model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART) and maximum entropy (Maxent) models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5): 642-647, 2011].

  3. Communication system modeling

    NASA Technical Reports Server (NTRS)

    Holland, L. D.; Walsh, J. R., Jr.; Wetherington, R. D.

    1971-01-01

    This report presents the results of work on communications systems modeling and covers three different areas of modeling. The first of these deals with the modeling of signals in communication systems in the frequency domain and the calculation of spectra for various modulations. These techniques are applied in determining the frequency spectra produced by a unified carrier system, the down-link portion of the Command and Communications System (CCS). The second modeling area covers the modeling of portions of a communication system on a block basis. A detailed analysis and modeling effort based on control theory is presented along with its application to modeling of the automatic frequency control system of an FM transmitter. A third topic discussed is a method for approximate modeling of stiff systems using state variable techniques.

  4. Protein solubility modeling

    NASA Technical Reports Server (NTRS)

    Agena, S. M.; Pusey, M. L.; Bogle, I. D.

    1999-01-01

    A thermodynamic framework (UNIQUAC model with temperature dependent parameters) is applied to model the salt-induced protein crystallization equilibrium, i.e., protein solubility. The framework introduces a term for the solubility product describing protein transfer between the liquid and solid phase and a term for the solution behavior describing deviation from ideal solution. Protein solubility is modeled as a function of salt concentration and temperature for a four-component system consisting of a protein, pseudo solvent (water and buffer), cation, and anion (salt). Two different systems, lysozyme with sodium chloride and concanavalin A with ammonium sulfate, are investigated. Comparison of the modeled and experimental protein solubility data results in an average root mean square deviation of 5.8%, demonstrating that the model closely follows the experimental behavior. Model calculations and model parameters are reviewed to examine the model and protein crystallization process. Copyright 1999 John Wiley & Sons, Inc.

  5. SEDIMENT GEOCHEMICAL MODEL

    EPA Science Inventory

    Until recently, sediment geochemical models (diagenetic models) have been only able to explain sedimentary flux and concentration profiles for a few simplified geochemical cycles (e.g., nitrogen, carbon and sulfur). However with advances in numerical methods, increased accuracy ...

  6. Mass modeling for bars

    NASA Technical Reports Server (NTRS)

    Butler, Thomas G.

    1987-01-01

    Methods of modeling mass for bars are surveyed. A method for extending John Archer's concept of consistent mass beyond just translational inertia effects is included. Recommendations are given for various types of modeling situations.

  7. Models (Part 1).

    ERIC Educational Resources Information Center

    Callison, Daniel

    2002-01-01

    Defines models and describes information search models that can be helpful to instructional media specialists in meeting users' abilities and information needs. Explains pathfinders and Kuhlthau's information search process, including the pre-writing information search process. (LRW)

  8. Modeling Infectious Diseases

    MedlinePlus

    ... MIDAS models require a breadth of knowledge, the network draws together an interdisciplinary team of researchers with expertise in epidemiology, infectious diseases, computational biology, statistics, social sciences, physics, computer sciences and informatics. In 2006, MIDAS modelers simulated ...

  9. Of Molecules and Models.

    ERIC Educational Resources Information Center

    Brinner, Bonnie

    1992-01-01

    Presents an activity in which models help students visualize both the DNA process and transcription. After constructing DNA, RNA messenger, and RNA transfer molecules; students model cells, protein synthesis, codons, and RNA movement. (MDH)

  10. Consistent model driven architecture

    NASA Astrophysics Data System (ADS)

    Niepostyn, Stanisław J.

    2015-09-01

    The goal of the MDA is to produce software systems from abstract models in a way where human interaction is restricted to a minimum. These abstract models are based on the UML language. However, the semantics of UML models is defined in a natural language. Subsequently the verification of consistency of these diagrams is needed in order to identify errors in requirements at the early stage of the development process. The verification of consistency is difficult due to a semi-formal nature of UML diagrams. We propose automatic verification of consistency of the series of UML diagrams originating from abstract models implemented with our consistency rules. This Consistent Model Driven Architecture approach enables us to generate automatically complete workflow applications from consistent and complete models developed from abstract models (e.g. Business Context Diagram). Therefore, our method can be used to check practicability (feasibility) of software architecture models.

  11. Modeling DNA Replication.

    ERIC Educational Resources Information Center

    Bennett, Joan

    1998-01-01

    Recommends the use of a model of DNA made out of Velcro to help students visualize the steps of DNA replication. Includes a materials list, construction directions, and details of the demonstration using the model parts. (DDR)

  12. System Advisor Model

    2010-03-01

    The System Advisor Model (SAM) is a performance and economic model designed to facilitate decision making for people involved in the renewable energy industry, ranging from project managers and engineers to incentive program designers, technology developers, and researchers.

  13. Future of groundwater modeling

    USGS Publications Warehouse

    Langevin, Christian D.; Panday, Sorab

    2012-01-01

    With an increasing need to better manage water resources, the future of groundwater modeling is bright and exciting. However, while the past can be described and the present is known, the future of groundwater modeling, just like a groundwater model result, is highly uncertain and any prediction is probably not going to be entirely representative. Thus we acknowledge this as we present our vision of where groundwater modeling may be headed.

  14. Mathematical circulatory system model

    NASA Technical Reports Server (NTRS)

    Lakin, William D. (Inventor); Stevens, Scott A. (Inventor)

    2010-01-01

    A system and method of modeling a circulatory system including a regulatory mechanism parameter. In one embodiment, a regulatory mechanism parameter in a lumped parameter model is represented as a logistic function. In another embodiment, the circulatory system model includes a compliant vessel, the model having a parameter representing a change in pressure due to contraction of smooth muscles of a wall of the vessel.

  15. Modeling of spacecraft charging

    NASA Technical Reports Server (NTRS)

    Whipple, E. C., Jr.

    1977-01-01

    Three types of modeling of spacecraft charging are discussed: statistical models, parametric models, and physical models. Local time dependence of circuit upset for DoD and communication satellites, and electron current to a sphere with an assumed Debye potential distribution are presented. Four regions were involved in spacecraft charging: (1) undisturbed plasma, (2) plasma sheath region, (3) spacecraft surface, and (4) spacecraft equivalent circuit.

  16. Hierarchical Bass model

    NASA Astrophysics Data System (ADS)

    Tashiro, Tohru

    2014-03-01

    We propose a new model about diffusion of a product which includes a memory of how many adopters or advertisements a non-adopter met, where (non-)adopters mean people (not) possessing the product. This effect is lacking in the Bass model. As an application, we utilize the model to fit the iPod sales data, and so the better agreement is obtained than the Bass model.

  17. Wonderland climate model

    NASA Astrophysics Data System (ADS)

    Hansen, J.; Ruedy, R.; Lacis, A.; Russell, G.; Sato, M.; Lerner, J.; Rind, D.; Stone, P.

    1997-03-01

    We obtain a highly efficient global climate model by defining a sector version (120° of longitude) of the coarse resolution Goddard Institute for Space Studies model II. The geography of Wonderland is chosen such that the amount of land as a function of latitude is the same as on Earth. We show that the zonal mean climate of the Wonderland model is very similar to that of the parent model II.

  18. Soil moisture modeling review

    NASA Technical Reports Server (NTRS)

    Hildreth, W. W.

    1978-01-01

    A determination of the state of the art in soil moisture transport modeling based on physical or physiological principles was made. It was found that soil moisture models based on physical principles have been under development for more than 10 years. However, these models were shown to represent infiltration and redistribution of soil moisture quite well. Evapotranspiration has not been as adequately incorporated into the models.

  19. Modeling Complex Calorimeters

    NASA Technical Reports Server (NTRS)

    Figueroa-Feliciano, Enectali

    2004-01-01

    We have developed a software suite that models complex calorimeters in the time and frequency domain. These models can reproduce all measurements that we currently do in a lab setting, like IV curves, impedance measurements, noise measurements, and pulse generation. Since all these measurements are modeled from one set of parameters, we can fully describe a detector and characterize its behavior. This leads to a model than can be used effectively for engineering and design of detectors for particular applications.

  20. Updating applied diffusion models

    SciTech Connect

    Weil, J.C.

    1985-11-01

    Most diffusion models currently used in air quality applications are substantially out of date with understanding of turbulence and diffusion in the planetary boundary layer. Under a Cooperative Agreement with the Environmental Protection Agency, the American Meteorological Society organized a workshop to help improve the basis of such models, their physics and hopefuly their performance. Reviews and recommendations were made on models in three areas: diffusion in the convective boundary layer (CBL), diffusion in the stabe boundary layer (SBL), and model uncertainty.

  1. Models of change.

    PubMed

    Reineck, Carol

    2007-09-01

    Implementing change in organizations is a key nursing leadership competency. At the same time, it is a daunting responsibility. Fortunately, models of successful change illustrate useful concepts for leaders. Change concepts embedded in successful models include careful use of power, reason, reeducation, structure, behavior, and technology. This article discusses models of change. Learning from models may help nurse executives avoid perils such as change fatigue and may promote smoother movement toward safer systems of care.

  2. A Model Chemistry Class.

    ERIC Educational Resources Information Center

    Summerlin, Lee; Borgford, Christie

    1989-01-01

    Described is an activity which uses a 96-well reaction plate and soda straws to construct a model of the periodic table of the elements. The model illustrates the ionization energies of the various elements. Construction of the model and related concepts are discussed. (CW)

  3. Generalized Latent Trait Models.

    ERIC Educational Resources Information Center

    Moustaki, Irini; Knott, Martin

    2000-01-01

    Discusses a general model framework within which manifest variables with different distributions in the exponential family can be analyzed with a latent trait model. Presents a unified maximum likelihood method for estimating the parameters of the generalized latent trait model and discusses the scoring of individuals on the latent dimensions.…

  4. Modern Media Education Models

    ERIC Educational Resources Information Center

    Fedorov, Alexander

    2011-01-01

    The author supposed that media education models can be divided into the following groups: (1) educational-information models (the study of the theory, history, language of media culture, etc.), based on the cultural, aesthetic, semiotic, socio-cultural theories of media education; (2) educational-ethical models (the study of moral, religions,…

  5. Modeling EERE Deployment Programs

    SciTech Connect

    Cort, K. A.; Hostick, D. J.; Belzer, D. B.; Livingston, O. V.

    2007-11-01

    This report compiles information and conclusions gathered as part of the “Modeling EERE Deployment Programs” project. The purpose of the project was to identify and characterize the modeling of deployment programs within the EERE Technology Development (TD) programs, address possible improvements to the modeling process, and note gaps in knowledge in which future research is needed.

  6. Campus Energy Modeling Platform

    SciTech Connect

    Sides, Scott; Kemper, Travis; Larsen, Ross; Graf, Peter

    2014-09-19

    NREL's Campus Energy Modeling project provides a suite of simulation tools for integrated, data driven energy modeling of commercial buildings and campuses using Simulink. The tools enable development of fully interconnected models for commercial campus energy infrastructure, including electrical distribution systems, district heating and cooling, onsite generation (both conventional and renewable), building loads, energy storage, and control systems.

  7. Biophysical and spectral modeling

    NASA Technical Reports Server (NTRS)

    Goel, N. S. (Principal Investigator)

    1982-01-01

    Activities and results of a project to develop strategies for modeling vegetative canopy reflectance are reported. Specific tasks included the inversion of canopy reflectance models to estimate agronomic variables (particularly leaf area index) from in-situ reflectance measurements, and a study of possible uses of ecological models in analyzing temporal profiles of greenness.

  8. Modeling rapidly rotating stars

    NASA Astrophysics Data System (ADS)

    Rieutord, M.

    2006-06-01

    We review the quest of modeling rapidly rotating stars during the past 40 years and detail the challenges to be taken up by models facing new data from interferometry, seismology, spectroscopy... We then present the progress of the ESTER project aimed at giving a physically self-consistent model for the structure and evolution of rapidly rotating stars.

  9. IR DIAL performance modeling

    SciTech Connect

    Sharlemann, E.T.

    1994-07-01

    We are developing a DIAL performance model for CALIOPE at LLNL. The intent of the model is to provide quick and interactive parameter sensitivity calculations with immediate graphical output. A brief overview of the features of the performance model is given, along with an example of performance calculations for a non-CALIOPE application.

  10. Crushed Salt Constitutive Model

    SciTech Connect

    Callahan, G.D.

    1999-02-01

    The constitutive model used to describe the deformation of crushed salt is presented in this report. Two mechanisms -- dislocation creep and grain boundary diffusional pressure solution -- are combined to form the basis for the constitutive model governing the deformation of crushed salt. The constitutive model is generalized to represent three-dimensional states of stress. Upon complete consolidation, the crushed-salt model reproduces the Multimechanism Deformation (M-D) model typically used for the Waste Isolation Pilot Plant (WIPP) host geological formation salt. New shear consolidation tests are combined with an existing database that includes hydrostatic consolidation and shear consolidation tests conducted on WIPP and southeastern New Mexico salt. Nonlinear least-squares model fitting to the database produced two sets of material parameter values for the model -- one for the shear consolidation tests and one for a combination of the shear and hydrostatic consolidation tests. Using the parameter values determined from the fitted database, the constitutive model is validated against constant strain-rate tests. Shaft seal problems are analyzed to demonstrate model-predicted consolidation of the shaft seal crushed-salt component. Based on the fitting statistics, the ability of the model to predict the test data, and the ability of the model to predict load paths and test data outside of the fitted database, the model appears to capture the creep consolidation behavior of crushed salt reasonably well.

  11. A Model Performance

    ERIC Educational Resources Information Center

    Thornton, Bradley D.; Smalley, Robert A.

    2008-01-01

    Building information modeling (BIM) uses three-dimensional modeling concepts, information technology and interoperable software to design, construct and operate a facility. However, BIM can be more than a tool for virtual modeling--it can provide schools with a 3-D walkthrough of a project while it still is on the electronic drawing board. BIM can…

  12. Modeling Natural Selection

    ERIC Educational Resources Information Center

    Bogiages, Christopher A.; Lotter, Christine

    2011-01-01

    In their research, scientists generate, test, and modify scientific models. These models can be shared with others and demonstrate a scientist's understanding of how the natural world works. Similarly, students can generate and modify models to gain a better understanding of the content, process, and nature of science (Kenyon, Schwarz, and Hug…

  13. Progress in mix modeling

    SciTech Connect

    Harrison, A.K.

    1997-03-14

    We have identified the Cranfill multifluid turbulence model (Cranfill, 1992) as a starting point for development of subgrid models of instability, turbulent and mixing processes. We have differenced the closed system of equations in conservation form, and coded them in the object-oriented hydrodynamics code FLAG, which is to be used as a testbed for such models.

  14. Modelling a Suspension Bridge.

    ERIC Educational Resources Information Center

    Rawlins, Phil

    1991-01-01

    The quadratic function can be modeled in real life by a suspension bridge that supports a uniform weight. This activity uses concrete models and computer generated graphs to discover the mathematical model of the shape of the main cable of a suspension bridge. (MDH)

  15. Tests of Rating Models

    ERIC Educational Resources Information Center

    Masin, Sergio Cesare; Busetto, Martina

    2010-01-01

    The study reports empirical tests of Anderson's, Haubensak's, Helson's, and Parducci's rating models when two end anchors are used for rating. The results show that these models cannot predict the judgment effect called here the Dai Pra effect. It is shown that an extension of Anderson's model is consistent with this effect. The results confirm…

  16. Molecular Models in Biology

    ERIC Educational Resources Information Center

    Goodman, Richard E.

    1970-01-01

    Describes types of molecular models (ball-and-stick, framework, and space-filling) and evaluates commercially available kits. Gives instructions for constructive models from polystyrene balls and pipe-cleaners. Models are useful for class demonstrations although not sufficiently accurate for research use. Illustrations show biologically important…

  17. Open Source Molecular Modeling

    PubMed Central

    Pirhadi, Somayeh; Sunseri, Jocelyn; Koes, David Ryan

    2016-01-01

    The success of molecular modeling and computational chemistry efforts are, by definition, dependent on quality software applications. Open source software development provides many advantages to users of modeling applications, not the least of which is that the software is free and completely extendable. In this review we categorize, enumerate, and describe available open source software packages for molecular modeling and computational chemistry. PMID:27631126

  18. Impact-GMI Model

    2007-03-22

    IMPACT-GMI is an atmospheric chemical transport model designed to run on massively parallel computers. It is designed to model trace pollutants in the atmosphere. It includes models for emission, chemistry and deposition of pollutants. It can be used to assess air quality and its impact on future climate change.

  19. Modeling Climate Dynamically

    ERIC Educational Resources Information Center

    Walsh, Jim; McGehee, Richard

    2013-01-01

    A dynamical systems approach to energy balance models of climate is presented, focusing on low order, or conceptual, models. Included are global average and latitude-dependent, surface temperature models. The development and analysis of the differential equations and corresponding bifurcation diagrams provides a host of appropriate material for…

  20. Elementary Teacher Training Models.

    ERIC Educational Resources Information Center

    Blewett, Evelyn J., Ed.

    This collection of articles contains descriptions of nine elementary teacher training program models conducted at universities throughout the United States. The articles include the following: (a) "The University of Toledo Model Program," by George E. Dickson; (b) "The Florida State University Model Program," by G. Wesley Sowards; (c) "The…

  1. Model Breaking Points Conceptualized

    ERIC Educational Resources Information Center

    Vig, Rozy; Murray, Eileen; Star, Jon R.

    2014-01-01

    Current curriculum initiatives (e.g., National Governors Association Center for Best Practices and Council of Chief State School Officers 2010) advocate that models be used in the mathematics classroom. However, despite their apparent promise, there comes a point when models break, a point in the mathematical problem space where the model cannot,…

  2. Rock Properties Model

    SciTech Connect

    C. Lum

    2004-09-16

    The purpose of this model report is to document the Rock Properties Model version 3.1 with regard to input data, model methods, assumptions, uncertainties and limitations of model results, and qualification status of the model. The report also documents the differences between the current and previous versions and validation of the model. The rock properties model provides mean matrix and lithophysae porosity, and the cross-correlated mean bulk density as direct input to the ''Saturated Zone Flow and Transport Model Abstraction'', MDL-NBS-HS-000021, REV 02 (BSC 2004 [DIRS 170042]). The constraints, caveats, and limitations associated with this model are discussed in Section 6.6 and 8.2. Model validation accomplished by corroboration with data not cited as direct input is discussed in Section 7. The revision of this model report was performed as part of activities being conducted under the ''Technical Work Plan for: The Integrated Site Model, Revision 05'' (BSC 2004 [DIRS 169635]). The purpose of this revision is to bring the report up to current procedural requirements and address the Regulatory Integration Team evaluation comments. The work plan describes the scope, objectives, tasks, methodology, and procedures for this process.

  3. Modeling and Remodeling Writing

    ERIC Educational Resources Information Center

    Hayes, John R.

    2012-01-01

    In Section 1 of this article, the author discusses the succession of models of adult writing that he and his colleagues have proposed from 1980 to the present. He notes the most important changes that differentiate earlier and later models and discusses reasons for the changes. In Section 2, he describes his recent efforts to model young…

  4. Models, Norms and Sharing.

    ERIC Educational Resources Information Center

    Harris, Mary B.

    To investigate the effect of modeling on altruism, 156 third and fifth grade children were exposed to a model who either shared with them, gave to a charity, or refused to share. The test apparatus, identified as a game, consisted of a box with signal lights and a chute through which marbles were dispensed. Subjects and the model played the game…

  5. Models for Products

    ERIC Educational Resources Information Center

    Speiser, Bob; Walter, Chuck

    2011-01-01

    This paper explores how models can support productive thinking. For us a model is a "thing", a tool to help make sense of something. We restrict attention to specific models for whole-number multiplication, hence the wording of the title. They support evolving thinking in large measure through the ways their users redesign them. They assume new…

  6. Model Rockets and Microchips.

    ERIC Educational Resources Information Center

    Fitzsimmons, Charles P.

    1986-01-01

    Points out the instructional applications and program possibilities of a unit on model rocketry. Describes the ways that microcomputers can assist in model rocket design and in problem calculations. Provides a descriptive listing of model rocket software for the Apple II microcomputer. (ML)

  7. New Directions for Modeling?

    ERIC Educational Resources Information Center

    Mason, Thomas R.

    1976-01-01

    Noting the disappointing results of past experimentation with computer modeling technology in higher education, the author discusses developments which promise potential: communication between model builders and users, interaction between large- and small-scale models, interface with operating data systems, emphasis on outcomes, and continued…

  8. Surface complexation modeling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adsorption-desorption reactions are important processes that affect the transport of contaminants in the environment. Surface complexation models are chemical models that can account for the effects of variable chemical conditions, such as pH, on adsorption reactions. These models define specific ...

  9. Modelling Vocabulary Loss

    ERIC Educational Resources Information Center

    Meara, Paul

    2004-01-01

    This paper describes some simple simulation models of vocabulary attrition. The attrition process is modelled using a random autonomous Boolean network model, and some parallels with real attrition data are drawn. The paper argues that applying a complex systems approach to attrition can provide some important insights, which suggest that real…

  10. Modelling MIZ dynamics in a global model

    NASA Astrophysics Data System (ADS)

    Rynders, Stefanie; Aksenov, Yevgeny; Feltham, Daniel; Nurser, George; Naveira Garabato, Alberto

    2016-04-01

    Exposure of large, previously ice-covered areas of the Arctic Ocean to the wind and surface ocean waves results in the Arctic pack ice cover becoming more fragmented and mobile, with large regions of ice cover evolving into the Marginal Ice Zone (MIZ). The need for better climate predictions, along with growing economic activity in the Polar Oceans, necessitates climate and forecasting models that can simulate fragmented sea ice with a greater fidelity. Current models are not fully fit for the purpose, since they neither model surface ocean waves in the MIZ, nor account for the effect of floe fragmentation on drag, nor include sea ice rheology that represents both the now thinner pack ice and MIZ ice dynamics. All these processes affect the momentum transfer to the ocean. We present initial results from a global ocean model NEMO (Nucleus for European Modelling of the Ocean) coupled to the Los Alamos sea ice model CICE. The model setup implements a novel rheological formulation for sea ice dynamics, accounting for ice floe collisions, thus offering a seamless framework for pack ice and MIZ simulations. The effect of surface waves on ice motion is included through wave pressure and the turbulent kinetic energy of ice floes. In the multidecadal model integrations we examine MIZ and basin scale sea ice and oceanic responses to the changes in ice dynamics. We analyse model sensitivities and attribute them to key sea ice and ocean dynamical mechanisms. The results suggest that the effect of the new ice rheology is confined to the MIZ. However with the current increase in summer MIZ area, which is projected to continue and may become the dominant type of sea ice in the Arctic, we argue that the effects of the combined sea ice rheology will be noticeable in large areas of the Arctic Ocean, affecting sea ice and ocean. With this study we assert that to make more accurate sea ice predictions in the changing Arctic, models need to include MIZ dynamics and physics.

  11. Adapting industry-style business model to academia in a system of Performance-based Incentive Compensation.

    PubMed

    Reece, E Albert; Nugent, Olan; Wheeler, Richard P; Smith, Charles W; Hough, Aubrey J; Winter, Charles

    2008-01-01

    Performance-Based Incentive Compensation (PBIC) plans currently prevail throughout industry and have repeatedly demonstrated effectiveness as powerful motivational tools for attracting and retaining top talent, enhancing key indicators, increasing employee productivity, and, ultimately, enhancing mission-based parameters. The University of Arkansas for Medical Sciences (UAMS) College of Medicine introduced its PBIC plan to further the transition of the college to a high-performing academic and clinical enterprise. A forward-thinking compensation plan was progressively implemented during a three-year period. After the introduction of an aggressive five-year vision plan in 2002, the college introduced a PBIC plan designed to ensure the retention and recruitment of high-quality faculty through the use of uncapped salaries that reflect each faculty member's clinical, research, and education duties. The PBIC plan was introduced with broad, schoolwide principles adaptable to each department and purposely flexible to allow for tailor-made algorithms to fit the specific approaches required by individual departments. As of July 2006, the college had begun to reap a variety of short-term benefits from Phase I of its PBIC program, including increases in revenue and faculty salaries, and increased faculty morale and satisfaction.Successful implementation of a PBIC plan depends on a host of factors, including the development of a process for evaluating performance that is considered fair and reliable to the entire faculty. The college has become more efficient and effective by adopting such a program, which has helped it to increase overall productivity. The PBIC program continues to challenge our faculty members to attain their highest potential while rewarding them accordingly. PMID:18162757

  12. Technical Report -- Essentials of which will be published as a journal paper

    SciTech Connect

    Harindra J. S. Fernando; James Anderson; Don Boyer

    2005-10-25

    Vertical Transport and Mixing in Complex Terrain Airsheds: Implementation of a Stable PBL Turbulence Parameterization for the Mesoscale Model MM5 The difficulties associated with parameterization of turbulence in the stable nocturnal atmospheric boundary layer have been a great challenge for the night-time predictions of mesoscale meteorological models such as MM5. As such, there is a general consensus on the need for better stable boundary-layer parameterizations. To this end, two new turbulence parameterizations based on the measurements of the Vertical Transport and Mixing (VTMX) field campaign were implemented and evaluated in MM5. A unique aspect of this parameterization is the use of a stability dependent turbulent Prandtl number that allows momentum to be transported by the internal waves, while heat diffusion is impeded by the stratification. This improvement alleviates the problem of over-prediction of heat diffusion under stable conditions, which is a characteristic of conventional PBL schemes, such as MRF and Blackadar schemes employed in MM5. The predictions made with the new PBL scheme for the complex terrain airshed of Salt Lake City were compared with those made with a default scheme of MM5 and with observations made during the VTMX campaign. The new schemes showed an improvement in predictions, particularly for the nocturnal near surface temperature. Surface wind predictions also improved slightly, but not to the extent of temperature predictions. The default MRF scheme showed a significantly warmer surface temperature than observed, which could be attributed to the enhanced vertical heat exchange brought about by its turbulence parameterization. The modified parameterizations reduced the surface sensible heat flux, thus enhancing the strength of the near surface inversion and lowering the temperature toward the observed values.

  13. Advances in Watershed Models and Modeling

    NASA Astrophysics Data System (ADS)

    Yeh, G. T.; Zhang, F.

    2015-12-01

    The development of watershed models and their applications to real-world problems has evolved significantly since 1960's. Watershed models can be classified based on what media are included, what processes are dealt with, and what approaches are taken. In term of media, a watershed may include segregated overland regime, river-canal-open channel networks, ponds-reservoirs-small lakes, and subsurface media. It may also include integrated media of all these or a partial set of these as well as man-made control structures. In term of processes, a watershed model may deal with coupled or decoupled hydrological and biogeochemical cycles. These processes include fluid flow, thermal transport, salinity transport, sediment transport, reactive transport, and biota and microbe kinetics. In terms of approaches, either parametric or physics-based approach can be taken. This talk discusses the evolution of watershed models in the past sixty years. The advances of watershed models center around their increasing design capability to foster these segregated or integrated media and coupled or decoupled processes. Widely used models developed by academia, research institutes, government agencies, and private industries will be reviewed in terms of the media and processes included as well as approaches taken. Many types of potential benchmark problems in general can be proposed and will be discussed. This presentation will focus on three benchmark problems of biogeochemical cycles. These three problems, dealing with water quality transport, will be formulated in terms of reactive transport. Simulation results will be illustrated using WASH123D, a watershed model developed and continuously updated by the author and his PhD graduates. Keywords: Hydrological Cycles, Biogeochemical Cycles, Biota Kinetics, Parametric Approach, Physics-based Approach, Reactive Transport.

  14. Transgenesis for pig models

    PubMed Central

    Yum, Soo-Young; Yoon, Ki-Young; Lee, Choong-Il; Lee, Byeong-Chun

    2016-01-01

    Animal models, particularly pigs, have come to play an important role in translational biomedical research. There have been many pig models with genetically modifications via somatic cell nuclear transfer (SCNT). However, because most transgenic pigs have been produced by random integration to date, the necessity for more exact gene-mutated models using recombinase based conditional gene expression like mice has been raised. Currently, advanced genome-editing technologies enable us to generate specific gene-deleted and -inserted pig models. In the future, the development of pig models with gene editing technologies could be a valuable resource for biomedical research. PMID:27030199

  15. The FREZCHEM Model

    NASA Astrophysics Data System (ADS)

    Marion, Giles M.; Kargel, Jeffrey S.

    Implementation of the Pitzer approach is through the FREZCHEM (FREEZING CHEMISTRY) model, which is at the core of this work. This model was originally designed to simulate salt chemistries and freezing processes at low temperatures (-54 to 25°C) and 1 atm pressure. Over the years, this model has been broadened to include more chemistries (from 16 to 58 solid phases), a broader temperature range for some chemistries (to 113°C), and incorporation of a pressure dependence (1 to 1000 bars) into the model. Implementation, parameterization, validation, and limitations of the FREZCHEM model are extensively discussed in Chapter 3.

  16. Mechanics of materials model

    NASA Technical Reports Server (NTRS)

    Meister, Jeffrey P.

    1987-01-01

    The Mechanics of Materials Model (MOMM) is a three-dimensional inelastic structural analysis code for use as an early design stage tool for hot section components. MOMM is a stiffness method finite element code that uses a network of beams to characterize component behavior. The MOMM contains three material models to account for inelastic material behavior. These include the simplified material model, which assumes a bilinear stress-strain response; the state-of-the-art model, which utilizes the classical elastic-plastic-creep strain decomposition; and Walker's viscoplastic model, which accounts for the interaction between creep and plasticity that occurs under cyclic loading conditions.

  17. Models of Goldstone gauginos

    NASA Astrophysics Data System (ADS)

    Alves, Daniele S. M.; Galloway, Jamison; McCullough, Matthew; Weiner, Neal

    2016-04-01

    Models with Dirac gauginos are appealing scenarios for physics beyond the Standard Model. They have smaller radiative corrections to scalar soft masses, a suppression of certain supersymmetry (SUSY) production processes at the LHC, and ameliorated flavor constraints. Unfortunately, they are generically plagued by tachyons charged under the Standard Model, and attempts to eliminate such states typically spoil the positive features. The recently proposed "Goldstone gaugino" mechanism provides a simple realization of Dirac gauginos that is automatically free of dangerous tachyonic states. We provide details on this mechanism and explore models for its origin. In particular, we find SUSY QCD models that realize this idea simply and discuss scenarios for unification.

  18. UZ Colloid Transport Model

    SciTech Connect

    M. McGraw

    2000-04-13

    The UZ Colloid Transport model development plan states that the objective of this Analysis/Model Report (AMR) is to document the development of a model for simulating unsaturated colloid transport. This objective includes the following: (1) use of a process level model to evaluate the potential mechanisms for colloid transport at Yucca Mountain; (2) Provide ranges of parameters for significant colloid transport processes to Performance Assessment (PA) for the unsaturated zone (UZ); (3) Provide a basis for development of an abstracted model for use in PA calculations.

  19. CRAC2 model description

    SciTech Connect

    Ritchie, L.T.; Alpert, D.J.; Burke, R.P.; Johnson, J.D.; Ostmeyer, R.M.; Aldrich, D.C.; Blond, R.M.

    1984-03-01

    The CRAC2 computer code is a revised version of CRAC (Calculation of Reactor Accident Consequences) which was developed for the Reactor Safety Study. This document provides an overview of the CRAC2 code and a description of each of the models used. Significant improvements incorporated into CRAC2 include an improved weather sequence sampling technique, a new evacuation model, and new output capabilities. In addition, refinements have been made to the atmospheric transport and deposition model. Details of the modeling differences between CRAC2 and CRAC are emphasized in the model descriptions.

  20. TEAMS Model Analyzer

    NASA Technical Reports Server (NTRS)

    Tijidjian, Raffi P.

    2010-01-01

    The TEAMS model analyzer is a supporting tool developed to work with models created with TEAMS (Testability, Engineering, and Maintenance System), which was developed by QSI. In an effort to reduce the time spent in the manual process that each TEAMS modeler must perform in the preparation of reporting for model reviews, a new tool has been developed as an aid to models developed in TEAMS. The software allows for the viewing, reporting, and checking of TEAMS models that are checked into the TEAMS model database. The software allows the user to selectively model in a hierarchical tree outline view that displays the components, failure modes, and ports. The reporting features allow the user to quickly gather statistics about the model, and generate an input/output report pertaining to all of the components. Rules can be automatically validated against the model, with a report generated containing resulting inconsistencies. In addition to reducing manual effort, this software also provides an automated process framework for the Verification and Validation (V&V) effort that will follow development of these models. The aid of such an automated tool would have a significant impact on the V&V process.

  1. A model of strength

    USGS Publications Warehouse

    Johnson, Douglas H.; Cook, R.D.

    2013-01-01

    In her AAAS News & Notes piece "Can the Southwest manage its thirst?" (26 July, p. 362), K. Wren quotes Ajay Kalra, who advocates a particular method for predicting Colorado River streamflow "because it eschews complex physical climate models for a statistical data-driven modeling approach." A preference for data-driven models may be appropriate in this individual situation, but it is not so generally, Data-driven models often come with a warning against extrapolating beyond the range of the data used to develop the models. When the future is like the past, data-driven models can work well for prediction, but it is easy to over-model local or transient phenomena, often leading to predictive inaccuracy (1). Mechanistic models are built on established knowledge of the process that connects the response variables with the predictors, using information obtained outside of an extant data set. One may shy away from a mechanistic approach when the underlying process is judged to be too complicated, but good predictive models can be constructed with statistical components that account for ingredients missing in the mechanistic analysis. Models with sound mechanistic components are more generally applicable and robust than data-driven models.

  2. Calibrated Properties Model

    SciTech Connect

    T. Ghezzehej

    2004-10-04

    The purpose of this model report is to document the calibrated properties model that provides calibrated property sets for unsaturated zone (UZ) flow and transport process models (UZ models). The calibration of the property sets is performed through inverse modeling. This work followed, and was planned in, ''Technical Work Plan (TWP) for: Unsaturated Zone Flow Analysis and Model Report Integration'' (BSC 2004 [DIRS 169654], Sections 1.2.6 and 2.1.1.6). Direct inputs to this model report were derived from the following upstream analysis and model reports: ''Analysis of Hydrologic Properties Data'' (BSC 2004 [DIRS 170038]); ''Development of Numerical Grids for UZ Flow and Transport Modeling'' (BSC 2004 [DIRS 169855]); ''Simulation of Net Infiltration for Present-Day and Potential Future Climates'' (BSC 2004 [DIRS 170007]); ''Geologic Framework Model'' (GFM2000) (BSC 2004 [DIRS 170029]). Additionally, this model report incorporates errata of the previous version and closure of the Key Technical Issue agreement TSPAI 3.26 (Section 6.2.2 and Appendix B), and it is revised for improved transparency.

  3. Distributed fuzzy system modeling

    SciTech Connect

    Pedrycz, W.; Chi Fung Lam, P.; Rocha, A.F.

    1995-05-01

    The paper introduces and studies an idea of distributed modeling treating it as a new paradigm of fuzzy system modeling and analysis. This form of modeling is oriented towards developing individual (local) fuzzy models for specific modeling landmarks (expressed as fuzzy sets) and determining the essential logical relationships between these local models. The models themselves are implemented in the form of logic processors being regarded as specialized fuzzy neural networks. The interaction between the processors is developed either in an inhibitory or excitatory way. In more descriptive way, the distributed model can be sought as a collection of fuzzy finite state machines with their individual local first or higher order memories. It is also clarified how the concept of distributed modeling narrows down a gap between purely numerical (quantitative) models and the qualitative ones originated within the realm of Artificial Intelligence. The overall architecture of distributed modeling is discussed along with the detailed learning schemes. The results of extensive simulation experiments are provided as well. 17 refs.

  4. Modelling Farm Animal Welfare

    PubMed Central

    Collins, Lisa M.; Part, Chérie E.

    2013-01-01

    Simple Summary In this review paper we discuss the different modeling techniques that have been used in animal welfare research to date. We look at what questions they have been used to answer, the advantages and pitfalls of the methods, and how future research can best use these approaches to answer some of the most important upcoming questions in farm animal welfare. Abstract The use of models in the life sciences has greatly expanded in scope and advanced in technique in recent decades. However, the range, type and complexity of models used in farm animal welfare is comparatively poor, despite the great scope for use of modeling in this field of research. In this paper, we review the different modeling approaches used in farm animal welfare science to date, discussing the types of questions they have been used to answer, the merits and problems associated with the method, and possible future applications of each technique. We find that the most frequently published types of model used in farm animal welfare are conceptual and assessment models; two types of model that are frequently (though not exclusively) based on expert opinion. Simulation, optimization, scenario, and systems modeling approaches are rarer in animal welfare, despite being commonly used in other related fields. Finally, common issues such as a lack of quantitative data to parameterize models, and model selection and validation are discussed throughout the review, with possible solutions and alternative approaches suggested. PMID:26487411

  5. Modelling structured data with Probabilistic Graphical Models

    NASA Astrophysics Data System (ADS)

    Forbes, F.

    2016-05-01

    Most clustering and classification methods are based on the assumption that the objects to be clustered are independent. However, in more and more modern applications, data are structured in a way that makes this assumption not realistic and potentially misleading. A typical example that can be viewed as a clustering task is image segmentation where the objects are the pixels on a regular grid and depend on neighbouring pixels on this grid. Also, when data are geographically located, it is of interest to cluster data with an underlying dependence structure accounting for some spatial localisation. These spatial interactions can be naturally encoded via a graph not necessarily regular as a grid. Data sets can then be modelled via Markov random fields and mixture models (e.g. the so-called MRF and Hidden MRF). More generally, probabilistic graphical models are tools that can be used to represent and manipulate data in a structured way while modeling uncertainty. This chapter introduces the basic concepts. The two main classes of probabilistic graphical models are considered: Bayesian networks and Markov networks. The key concept of conditional independence and its link to Markov properties is presented. The main problems that can be solved with such tools are described. Some illustrations are given associated with some practical work.

  6. Toward Scientific Numerical Modeling

    NASA Technical Reports Server (NTRS)

    Kleb, Bil

    2007-01-01

    Ultimately, scientific numerical models need quantified output uncertainties so that modeling can evolve to better match reality. Documenting model input uncertainties and verifying that numerical models are translated into code correctly, however, are necessary first steps toward that goal. Without known input parameter uncertainties, model sensitivities are all one can determine, and without code verification, output uncertainties are simply not reliable. To address these two shortcomings, two proposals are offered: (1) an unobtrusive mechanism to document input parameter uncertainties in situ and (2) an adaptation of the Scientific Method to numerical model development and deployment. Because these two steps require changes in the computational simulation community to bear fruit, they are presented in terms of the Beckhard-Harris-Gleicher change model.

  7. Foam process models.

    SciTech Connect

    Moffat, Harry K.; Noble, David R.; Baer, Thomas A.; Adolf, Douglas Brian; Rao, Rekha Ranjana; Mondy, Lisa Ann

    2008-09-01

    In this report, we summarize our work on developing a production level foam processing computational model suitable for predicting the self-expansion of foam in complex geometries. The model is based on a finite element representation of the equations of motion, with the movement of the free surface represented using the level set method, and has been implemented in SIERRA/ARIA. An empirically based time- and temperature-dependent density model is used to encapsulate the complex physics of foam nucleation and growth in a numerically tractable model. The change in density with time is at the heart of the foam self-expansion as it creates the motion of the foam. This continuum-level model uses an homogenized description of foam, which does not include the gas explicitly. Results from the model are compared to temperature-instrumented flow visualization experiments giving the location of the foam front as a function of time for our EFAR model system.

  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. Phyloclimatic modeling: combining phylogenetics and bioclimatic modeling.

    PubMed

    Yesson, C; Culham, A

    2006-10-01

    We investigate the impact of past climates on plant diversification by tracking the "footprint" of climate change on a phylogenetic tree. Diversity within the cosmopolitan carnivorous plant genus Drosera (Droseraceae) is focused within Mediterranean climate regions. We explore whether this diversity is temporally linked to Mediterranean-type climatic shifts of the mid-Miocene and whether climate preferences are conservative over phylogenetic timescales. Phyloclimatic modeling combines environmental niche (bioclimatic) modeling with phylogenetics in order to study evolutionary patterns in relation to climate change. We present the largest and most complete such example to date using Drosera. The bioclimatic models of extant species demonstrate clear phylogenetic patterns; this is particularly evident for the tuberous sundews from southwestern Australia (subgenus Ergaleium). We employ a method for establishing confidence intervals of node ages on a phylogeny using replicates from a Bayesian phylogenetic analysis. This chronogram shows that many clades, including subgenus Ergaleium and section Bryastrum, diversified during the establishment of the Mediterranean-type climate. Ancestral reconstructions of bioclimatic models demonstrate a pattern of preference for this climate type within these groups. Ancestral bioclimatic models are projected into palaeo-climate reconstructions for the time periods indicated by the chronogram. We present two such examples that each generate plausible estimates of ancestral lineage distribution, which are similar to their current distributions. This is the first study to attempt bioclimatic projections on evolutionary time scales. The sundews appear to have diversified in response to local climate development. Some groups are specialized for Mediterranean climates, others show wide-ranging generalism. This demonstrates that Phyloclimatic modeling could be repeated for other plant groups and is fundamental to the understanding of

  10. Phyloclimatic modeling: combining phylogenetics and bioclimatic modeling.

    PubMed

    Yesson, C; Culham, A

    2006-10-01

    We investigate the impact of past climates on plant diversification by tracking the "footprint" of climate change on a phylogenetic tree. Diversity within the cosmopolitan carnivorous plant genus Drosera (Droseraceae) is focused within Mediterranean climate regions. We explore whether this diversity is temporally linked to Mediterranean-type climatic shifts of the mid-Miocene and whether climate preferences are conservative over phylogenetic timescales. Phyloclimatic modeling combines environmental niche (bioclimatic) modeling with phylogenetics in order to study evolutionary patterns in relation to climate change. We present the largest and most complete such example to date using Drosera. The bioclimatic models of extant species demonstrate clear phylogenetic patterns; this is particularly evident for the tuberous sundews from southwestern Australia (subgenus Ergaleium). We employ a method for establishing confidence intervals of node ages on a phylogeny using replicates from a Bayesian phylogenetic analysis. This chronogram shows that many clades, including subgenus Ergaleium and section Bryastrum, diversified during the establishment of the Mediterranean-type climate. Ancestral reconstructions of bioclimatic models demonstrate a pattern of preference for this climate type within these groups. Ancestral bioclimatic models are projected into palaeo-climate reconstructions for the time periods indicated by the chronogram. We present two such examples that each generate plausible estimates of ancestral lineage distribution, which are similar to their current distributions. This is the first study to attempt bioclimatic projections on evolutionary time scales. The sundews appear to have diversified in response to local climate development. Some groups are specialized for Mediterranean climates, others show wide-ranging generalism. This demonstrates that Phyloclimatic modeling could be repeated for other plant groups and is fundamental to the understanding of

  11. Loehlin's original models and model contributions.

    PubMed

    McArdle, John J

    2014-11-01

    This is a short story about John C. Loehlin who is now at the University of Texas at Austin, dealing with his original simulation models and developments, which led to his current latent variable models. This talk was initially presented at a special meeting for John before the BGA in Rhode Island, and I was very pleased to contribute. It probably goes without saying, but John helped create this important society, has been a key contributor to this journal for several decades, and he deserves a lot for this leadership.

  12. Constitutive models in LAME.

    SciTech Connect

    Hammerand, Daniel Carl; Scherzinger, William Mark

    2007-09-01

    The Library of Advanced Materials for Engineering (LAME) provides a common repository for constitutive models that can be used in computational solid mechanics codes. A number of models including both hypoelastic (rate) and hyperelastic (total strain) constitutive forms have been implemented in LAME. The structure and testing of LAME is described in Scherzinger and Hammerand ([3] and [4]). The purpose of the present report is to describe the material models which have already been implemented into LAME. The descriptions are designed to give useful information to both analysts and code developers. Thus far, 33 non-ITAR/non-CRADA protected material models have been incorporated. These include everything from the simple isotropic linear elastic models to a number of elastic-plastic models for metals to models for honeycomb, foams, potting epoxies and rubber. A complete description of each model is outside the scope of the current report. Rather, the aim here is to delineate the properties, state variables, functions, and methods for each model. However, a brief description of some of the constitutive details is provided for a number of the material models. Where appropriate, the SAND reports available for each model have been cited. Many models have state variable aliases for some or all of their state variables. These alias names can be used for outputting desired quantities. The state variable aliases available for results output have been listed in this report. However, not all models use these aliases. For those models, no state variable names are listed. Nevertheless, the number of state variables employed by each model is always given. Currently, there are four possible functions for a material model. This report lists which of these four methods are employed in each material model. As far as analysts are concerned, this information is included only for the awareness purposes. The analyst can take confidence in the fact that model has been properly implemented

  13. Preliminary DIAL model

    SciTech Connect

    Gentry, S.; Taylor, J.; Stephenson, D.

    1994-06-01

    A unique end-to-end LIDAR sensor model has been developed supporting the concept development stage of the CALIOPE UV DIAL and UV laser-induced-fluorescence (LIF) efforts. The model focuses on preserving the temporal and spectral nature of signals as they pass through the atmosphere, are collected by the optics, detected by the sensor, and processed by the sensor electronics and algorithms. This is done by developing accurate component sub-models with realistic inputs and outputs, as well as internal noise sources and operating parameters. These sub-models are then configured using data-flow diagrams to operate together to reflect the performance of the entire DIAL system. This modeling philosophy allows the developer to have a realistic indication of the nature of signals throughout the system and to design components and processing in a realistic environment. Current component models include atmospheric absorption and scattering losses, plume absorption and scattering losses, background, telescope and optical filter models, PMT (photomultiplier tube) with realistic noise sources, amplifier operation and noise, A/D converter operation, noise and distortion, pulse averaging, and DIAL computation. Preliminary results of the model will be presented indicating the expected model operation depicting the October field test at the NTS spill test facility. Indications will be given concerning near-term upgrades to the model.

  14. Differential Topic Models.

    PubMed

    Chen, Changyou; Buntine, Wray; Ding, Nan; Xie, Lexing; Du, Lan

    2015-02-01

    In applications we may want to compare different document collections: they could have shared content but also different and unique aspects in particular collections. This task has been called comparative text mining or cross-collection modeling. We present a differential topic model for this application that models both topic differences and similarities. For this we use hierarchical Bayesian nonparametric models. Moreover, we found it was important to properly model power-law phenomena in topic-word distributions and thus we used the full Pitman-Yor process rather than just a Dirichlet process. Furthermore, we propose the transformed Pitman-Yor process (TPYP) to incorporate prior knowledge such as vocabulary variations in different collections into the model. To deal with the non-conjugate issue between model prior and likelihood in the TPYP, we thus propose an efficient sampling algorithm using a data augmentation technique based on the multinomial theorem. Experimental results show the model discovers interesting aspects of different collections. We also show the proposed MCMC based algorithm achieves a dramatically reduced test perplexity compared to some existing topic models. Finally, we show our model outperforms the state-of-the-art for document classification/ideology prediction on a number of text collections. PMID:26353238

  15. Quantitative Rheological Model Selection

    NASA Astrophysics Data System (ADS)

    Freund, Jonathan; Ewoldt, Randy

    2014-11-01

    The more parameters in a rheological the better it will reproduce available data, though this does not mean that it is necessarily a better justified model. Good fits are only part of model selection. We employ a Bayesian inference approach that quantifies model suitability by balancing closeness to data against both the number of model parameters and their a priori uncertainty. The penalty depends upon prior-to-calibration expectation of the viable range of values that model parameters might take, which we discuss as an essential aspect of the selection criterion. Models that are physically grounded are usually accompanied by tighter physical constraints on their respective parameters. The analysis reflects a basic principle: models grounded in physics can be expected to enjoy greater generality and perform better away from where they are calibrated. In contrast, purely empirical models can provide comparable fits, but the model selection framework penalizes their a priori uncertainty. We demonstrate the approach by selecting the best-justified number of modes in a Multi-mode Maxwell description of PVA-Borax. We also quantify relative merits of the Maxwell model relative to powerlaw fits and purely empirical fits for PVA-Borax, a viscoelastic liquid, and gluten.

  16. Geochemical modeling: a review

    SciTech Connect

    Jenne, E.A.

    1981-06-01

    Two general families of geochemical models presently exist. The ion speciation-solubility group of geochemical models contain submodels to first calculate a distribution of aqueous species and to secondly test the hypothesis that the water is near equilibrium with particular solid phases. These models may or may not calculate the adsorption of dissolved constituents and simulate the dissolution and precipitation (mass transfer) of solid phases. Another family of geochemical models, the reaction path models, simulates the stepwise precipitation of solid phases as a result of reacting specified amounts of water and rock. Reaction path models first perform an aqueous speciation of the dissolved constituents of the water, test solubility hypotheses, then perform the reaction path modeling. Certain improvements in the present versions of these models would enhance their value and usefulness to applications in nuclear-waste isolation, etc. Mass-transfer calculations of limited extent are certainly within the capabilities of state-of-the-art models. However, the reaction path models require an expansion of their thermodynamic data bases and systematic validation before they are generally accepted.

  17. Generalized Multilevel Structural Equation Modeling

    ERIC Educational Resources Information Center

    Rabe-Hesketh, Sophia; Skrondal, Anders; Pickles, Andrew

    2004-01-01

    A unifying framework for generalized multilevel structural equation modeling is introduced. The models in the framework, called generalized linear latent and mixed models (GLLAMM), combine features of generalized linear mixed models (GLMM) and structural equation models (SEM) and consist of a response model and a structural model for the latent…

  18. A Rasch Hierarchical Measurement Model.

    ERIC Educational Resources Information Center

    Maier, Kimberly S.

    This paper describes a model that integrates an item response theory (IRT) Rasch model and a hierarchical linear model and presents a method of estimating model parameter values that does not rely on large-sample theory and normal approximations. The model resulting from the integration of a hierarchical linear model and the Rasch model allows one…

  19. Modeling Imports in a Keynesian Expenditure Model

    ERIC Educational Resources Information Center

    Findlay, David W.

    2010-01-01

    The author discusses several issues that instructors of introductory macroeconomics courses should consider when introducing imports in the Keynesian expenditure model. The analysis suggests that the specification of the import function should partially, if not completely, be the result of a simple discussion about the spending and import…

  20. Energy balance climate models

    NASA Technical Reports Server (NTRS)

    North, G. R.; Cahalan, R. F.; Coakley, J. A., Jr.

    1981-01-01

    An introductory survey of the global energy balance climate models is presented with an emphasis on analytical results. A sequence of increasingly complicated models involving ice cap and radiative feedback processes are solved, and the solutions and parameter sensitivities are studied. The model parameterizations are examined critically in light of many current uncertainties. A simple seasonal model is used to study the effects of changes in orbital elements on the temperature field. A linear stability theorem and a complete nonlinear stability analysis for the models are developed. Analytical solutions are also obtained for the linearized models driven by stochastic forcing elements. In this context the relation between natural fluctuation statistics and climate sensitivity is stressed.

  1. Extended frequency turbofan model

    NASA Technical Reports Server (NTRS)

    Mason, J. R.; Park, J. W.; Jaekel, R. F.

    1980-01-01

    The fan model was developed using two dimensional modeling techniques to add dynamic radial coupling between the core stream and the bypass stream of the fan. When incorporated into a complete TF-30 engine simulation, the fan model greatly improved compression system frequency response to planar inlet pressure disturbances up to 100 Hz. The improved simulation also matched engine stability limits at 15 Hz, whereas the one dimensional fan model required twice the inlet pressure amplitude to stall the simulation. With verification of the two dimensional fan model, this program formulated a high frequency F-100(3) engine simulation using row by row compression system characteristics. In addition to the F-100(3) remote splitter fan, the program modified the model fan characteristics to simulate a proximate splitter version of the F-100(3) engine.

  2. Load Model Data Tool

    2013-04-30

    The LMDT software automates the process of the load composite model data preparation in the format supported by the major power system software vendors (GE and Siemens). Proper representation of the load composite model in power system dynamic analysis is very important. Software tools for power system simulation like GE PSLF and Siemens PSSE already include algorithms for the load composite modeling. However, these tools require that the input information on composite load to bemore » provided in custom formats. Preparation of this data is time consuming and requires multiple manual operations. The LMDT software enables to automate this process. Software is designed to generate composite load model data. It uses the default load composition data, motor information, and bus information as an input. Software processes the input information and produces load composition model. Generated model can be stored in .dyd format supported by GE PSLF package or .dyr format supported by Siemens PSSE package.« less

  3. Carcinogenesis models: An overview

    SciTech Connect

    Moolgavkar, S.H.

    1992-12-31

    Biologically based mathematical models of carcinogenesis are not only an essential part of a rational approach to quantitative cancer risk assessment but also raise fundamental questions about the nature of the events leading to malignancy. In this paper two such models are reviewed. The first is the multistage model proposed by Armitage and Doll in the 1950s; most of the paper is devoted to a discussion of the two-mutation model proposed by the author and his colleagues. This model is a generalization of the idea of recessive oncogenesis proposed by Knudson and has been shown to be consistent with a large body of epidemiologic and experimental data. The usefulness of the model is illustrated by analyzing a large experimental data set in which rats exposed to radon developed malignant lung tumors.

  4. Load Model Data Tool

    SciTech Connect

    David Chassin, Pavel Etingov

    2013-04-30

    The LMDT software automates the process of the load composite model data preparation in the format supported by the major power system software vendors (GE and Siemens). Proper representation of the load composite model in power system dynamic analysis is very important. Software tools for power system simulation like GE PSLF and Siemens PSSE already include algorithms for the load composite modeling. However, these tools require that the input information on composite load to be provided in custom formats. Preparation of this data is time consuming and requires multiple manual operations. The LMDT software enables to automate this process. Software is designed to generate composite load model data. It uses the default load composition data, motor information, and bus information as an input. Software processes the input information and produces load composition model. Generated model can be stored in .dyd format supported by GE PSLF package or .dyr format supported by Siemens PSSE package.

  5. Modelling of biofilm reactors

    SciTech Connect

    Rodrigues, A.; Grasmick, A.; Elmaleh, S.

    1982-10-01

    Comprehensive models of biofilm reactors are developed. Model I assumes a zero-order reaction of a limiting substrate and a diffusional mass transport through the biofilm; in the diffusion-controlled regime the model is fully characterized by one parameter alpha. From this model the conversion of substrate or reactor efficiency can be calculated, for continuously stirred tank reactors (CSTRs) and plug flow reactors respectively, as follows: EA = )alpha(alpha + 2)) 1/2 - alpha; and Ep = (2 alpha) 1/2 - alpha/2: Validation of the model is tested for different experimental systems. Model II includes liquid film mass transfer resistance. The conversion gap between plug flow reactors and CSTRs is always lower than 25% and, as a first approximation, the biofilm reactor design does not then require accurate residence time distribution measurements. (Refs. 23).

  6. Multiscale Cancer Modeling

    PubMed Central

    Macklin, Paul; Cristini, Vittorio

    2013-01-01

    Simulating cancer behavior across multiple biological scales in space and time, i.e., multiscale cancer modeling, is increasingly being recognized as a powerful tool to refine hypotheses, focus experiments, and enable more accurate predictions. A growing number of examples illustrate the value of this approach in providing quantitative insight on the initiation, progression, and treatment of cancer. In this review, we introduce the most recent and important multiscale cancer modeling works that have successfully established a mechanistic link between different biological scales. Biophysical, biochemical, and biomechanical factors are considered in these models. We also discuss innovative, cutting-edge modeling methods that are moving predictive multiscale cancer modeling toward clinical application. Furthermore, because the development of multiscale cancer models requires a new level of collaboration among scientists from a variety of fields such as biology, medicine, physics, mathematics, engineering, and computer science, an innovative Web-based infrastructure is needed to support this growing community. PMID:21529163

  7. Cloud model bat algorithm.

    PubMed

    Zhou, Yongquan; Xie, Jian; Li, Liangliang; Ma, Mingzhi

    2014-01-01

    Bat algorithm (BA) is a novel stochastic global optimization algorithm. Cloud model is an effective tool in transforming between qualitative concepts and their quantitative representation. Based on the bat echolocation mechanism and excellent characteristics of cloud model on uncertainty knowledge representation, a new cloud model bat algorithm (CBA) is proposed. This paper focuses on remodeling echolocation model based on living and preying characteristics of bats, utilizing the transformation theory of cloud model to depict the qualitative concept: "bats approach their prey." Furthermore, Lévy flight mode and population information communication mechanism of bats are introduced to balance the advantage between exploration and exploitation. The simulation results show that the cloud model bat algorithm has good performance on functions optimization. PMID:24967425

  8. Probabilistic Mesomechanical Fatigue Model

    NASA Technical Reports Server (NTRS)

    Tryon, Robert G.

    1997-01-01

    A probabilistic mesomechanical fatigue life model is proposed to link the microstructural material heterogeneities to the statistical scatter in the macrostructural response. The macrostructure is modeled as an ensemble of microelements. Cracks nucleation within the microelements and grow from the microelements to final fracture. Variations of the microelement properties are defined using statistical parameters. A micromechanical slip band decohesion model is used to determine the crack nucleation life and size. A crack tip opening displacement model is used to determine the small crack growth life and size. Paris law is used to determine the long crack growth life. The models are combined in a Monte Carlo simulation to determine the statistical distribution of total fatigue life for the macrostructure. The modeled response is compared to trends in experimental observations from the literature.

  9. Animal models of scoliosis.

    PubMed

    Bobyn, Justin D; Little, David G; Gray, Randolph; Schindeler, Aaron

    2015-04-01

    Multiple techniques designed to induce scoliotic deformity have been applied across many animal species. We have undertaken a review of the literature regarding experimental models of scoliosis in animals to discuss their utility in comprehending disease aetiology and treatment. Models of scoliosis in animals can be broadly divided into quadrupedal and bipedal experiments. Quadrupedal models, in the absence of axial gravitation force, depend upon development of a mechanical asymmetry along the spine to initiate a scoliotic deformity. Bipedal models more accurately mimic human posture and consequently are subject to similar forces due to gravity, which have been long appreciated to be a contributing factor to the development of scoliosis. Many effective models of scoliosis in smaller animals have not been successfully translated to primates and humans. Though these models may not clarify the aetiology of human scoliosis, by providing a reliable and reproducible deformity in the spine they are a useful means with which to test interventions designed to correct and prevent deformity.

  10. Outside users payload model

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The outside users payload model which is a continuation of documents and replaces and supersedes the July 1984 edition is presented. The time period covered by this model is 1985 through 2000. The following sections are included: (1) definition of the scope of the model; (2) discussion of the methodology used; (3) overview of total demand; (4) summary of the estimated market segmentation by launch vehicle; (5) summary of the estimated market segmentation by user type; (6) details of the STS market forecast; (7) summary of transponder trends; (8) model overview by mission category; and (9) detailed mission models. All known non-NASA, non-DOD reimbursable payloads forecast to be flown by non-Soviet-block countries are included in this model with the exception of Spacelab payloads and small self contained payloads. Certain DOD-sponsored or cosponsored payloads are included if they are reimbursable launches.

  11. Teaching macromolecular modeling.

    PubMed

    Harvey, S C; Tan, R K

    1992-12-01

    Training newcomers to the field of macromolecular modeling is as difficult as is training beginners in x-ray crystallography, nuclear magnetic resonance, or other methods in structural biology. In one or two lectures, the most that can be conveyed is a general sense of the relationship between modeling and other structural methods. If a full semester is available, then students can be taught how molecular structures are built, manipulated, refined, and analyzed on a computer. Here we describe a one-semester modeling course that combines lectures, discussions, and a laboratory using a commercial modeling package. In the laboratory, students carry out prescribed exercises that are coordinated to the lectures, and they complete a term project on a modeling problem of their choice. The goal is to give students an understanding of what kinds of problems can be attacked by molecular modeling methods and which problems are beyond the current capabilities of those methods.

  12. Open source molecular modeling.

    PubMed

    Pirhadi, Somayeh; Sunseri, Jocelyn; Koes, David Ryan

    2016-09-01

    The success of molecular modeling and computational chemistry efforts are, by definition, dependent on quality software applications. Open source software development provides many advantages to users of modeling applications, not the least of which is that the software is free and completely extendable. In this review we categorize, enumerate, and describe available open source software packages for molecular modeling and computational chemistry. An updated online version of this catalog can be found at https://opensourcemolecularmodeling.github.io.

  13. F-14 modeling study

    NASA Technical Reports Server (NTRS)

    Levison, W. H.; Baron, S.

    1984-01-01

    Preliminary results in the application of a closed loop pilot/simulator model to the analysis of some simulator fidelity issues are discussed in the context of an air to air target tracking task. The closed loop model is described briefly. Then, problem simplifications that are employed to reduce computational costs are discussed. Finally, model results showing sensitivity of performance to various assumptions concerning the simulator and/or the pilot are presented.

  14. Acid rain: Mesoscale model

    NASA Technical Reports Server (NTRS)

    Hsu, H. M.

    1980-01-01

    A mesoscale numerical model of the Florida peninsula was formulated and applied to a dry, neutral atmosphere. The prospective use of the STAR-100 computer for the submesoscale model is discussed. The numerical model presented is tested under synoptically undisturbed conditions. Two cases, differing only in the direction of the prevailing geostrophic wind, are examined: a prevailing southwest wind and a prevailing southeast wind, both 6 m/sec at all levels initially.

  15. Computer Models of Proteins

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Dr. Marc Pusey (seated) and Dr. Craig Kundrot use computers to analyze x-ray maps and generate three-dimensional models of protein structures. With this information, scientists at Marshall Space Flight Center can learn how proteins are made and how they work. The computer screen depicts a proten structure as a ball-and-stick model. Other models depict the actual volume occupied by the atoms, or the ribbon-like structures that are crucial to a protein's function.

  16. Modeling Frequency Comb Sources

    NASA Astrophysics Data System (ADS)

    Li, Feng; Yuan, Jinhui; Kang, Zhe; Li, Qian; Wai, P. K. A.

    2016-06-01

    Frequency comb sources have revolutionized metrology and spectroscopy and found applications in many fields. Stable, low-cost, high-quality frequency comb sources are important to these applications. Modeling of the frequency comb sources will help the understanding of the operation mechanism and optimization of the design of such sources. In this paper,we review the theoretical models used and recent progress of the modeling of frequency comb sources.

  17. The Integrated Medical Model

    NASA Technical Reports Server (NTRS)

    Kerstman, Eric; Minard, Charles; Saile, Lynn; Freiere deCarvalho, Mary; Myers, Jerry; Walton, Marlei; Butler, Douglas; Iyengar, Sriram; Johnson-Throop, Kathy; Baumann, David

    2010-01-01

    The goals of the Integrated Medical Model (IMM) are to develop an integrated, quantified, evidence-based decision support tool useful to crew health and mission planners and to help align science, technology, and operational activities intended to optimize crew health, safety, and mission success. Presentation slides address scope and approach, beneficiaries of IMM capabilities, history, risk components, conceptual models, development steps, and the evidence base. Space adaptation syndrome is used to demonstrate the model's capabilities.

  18. Atmospheric prediction model survey

    NASA Technical Reports Server (NTRS)

    Wellck, R. E.

    1976-01-01

    As part of the SEASAT Satellite program of NASA, a survey of representative primitive equation atmospheric prediction models that exist in the world today was written for the Jet Propulsion Laboratory. Seventeen models developed by eleven different operational and research centers throughout the world are included in the survey. The surveys are tutorial in nature describing the features of the various models in a systematic manner.

  19. Open source molecular modeling.

    PubMed

    Pirhadi, Somayeh; Sunseri, Jocelyn; Koes, David Ryan

    2016-09-01

    The success of molecular modeling and computational chemistry efforts are, by definition, dependent on quality software applications. Open source software development provides many advantages to users of modeling applications, not the least of which is that the software is free and completely extendable. In this review we categorize, enumerate, and describe available open source software packages for molecular modeling and computational chemistry. An updated online version of this catalog can be found at https://opensourcemolecularmodeling.github.io. PMID:27631126

  20. AREST model description

    SciTech Connect

    Engel, D.W.; McGrail, B.P.

    1993-11-01

    The Office of Civilian Radioactive Waste Management and the Power Reactor and Nuclear Fuel Development Corporation of Japan (PNC) have supported the development of the Analytical Repository Source-Term (AREST) at Pacific Northwest Laboratory. AREST is a computer model developed to evaluate radionuclide release from an underground geologic repository. The AREST code can be used to calculate/estimate the amount and rate of each radionuclide that is released from the engineered barrier system (EBS) of the repository. The EBS is the man-made or disrupted area of the repository. AREST was designed as a system-level models to simulate the behavior of the total repository by combining process-level models for the release from an individual waste package or container. AREST contains primarily analytical models for calculating the release/transport of radionuclides to the lost rock that surrounds each waste package. Analytical models were used because of the small computational overhead that allows all the input parameters to be derived from a statistical distribution. Recently, a one-dimensional numerical model was also incorporated into AREST, to allow for more detailed modeling of the transport process with arbitrary length decay chains. The next step in modeling the EBS, is to develop a model that couples the probabilistic capabilities of AREST with a more detailed process model. This model will need to look at the reactive coupling of the processes that are involved with the release process. Such coupling would include: (1) the dissolution of the waste form, (2) the geochemical modeling of the groundwater, (3) the corrosion of the container overpacking, and (4) the backfill material, just to name a few. Several of these coupled processes are already incorporated in the current version of AREST.

  1. Conceptual IT model

    NASA Astrophysics Data System (ADS)

    Arnaoudova, Kristina; Stanchev, Peter

    2015-11-01

    The business processes are the key asset for every organization. The design of the business process models is the foremost concern and target among an organization's functions. Business processes and their proper management are intensely dependent on the performance of software applications and technology solutions. The paper is attempt for definition of new Conceptual model of IT service provider, it could be examined as IT focused Enterprise model, part of Enterprise Architecture (EA) school.

  2. Global Atmospheric Aerosol Modeling

    NASA Technical Reports Server (NTRS)

    Hendricks, Johannes; Aquila, Valentina; Righi, Mattia

    2012-01-01

    Global aerosol models are used to study the distribution and properties of atmospheric aerosol particles as well as their effects on clouds, atmospheric chemistry, radiation, and climate. The present article provides an overview of the basic concepts of global atmospheric aerosol modeling and shows some examples from a global aerosol simulation. Particular emphasis is placed on the simulation of aerosol particles and their effects within global climate models.

  3. Liftoff Model for MELCOR.

    SciTech Connect

    Young, Michael F.

    2015-07-01

    Aerosol particles that deposit on surfaces may be subsequently resuspended by air flowing over the surface. A review of models for this liftoff process is presented and compared to available data. Based on this review, a model that agrees with existing data and is readily computed is presented for incorporation into a system level code such as MELCOR. Liftoff Model for MELCOR July 2015 4 This page is intentionally blank

  4. Determining air quality and greenhouse gas impacts of hydrogen infrastructure and fuel cell vehicles.

    PubMed

    Stephens-Romero, Shane; Carreras-Sospedra, Marc; Brouwer, Jacob; Dabdub, Donald; Samuelsen, Scott

    2009-12-01

    Adoption of hydrogen infrastructure and hydrogen fuel cell vehicles (HFCVs) to replace gasoline internal combustion engine (ICE) vehicles has been proposed as a strategy to reduce criteria pollutant and greenhouse gas (GHG) emissions from the transportation sector and transition to fuel independence. However, it is uncertain (1) to what degree the reduction in criteria pollutants will impact urban air quality, and (2) how the reductions in pollutant emissions and concomitant urban air quality impacts compare to ultralow emission gasoline-powered vehicles projected for a future year (e.g., 2060). To address these questions, the present study introduces a "spatially and temporally resolved energy and environment tool" (STREET) to characterize the pollutant and GHG emissions associated with a comprehensive hydrogen supply infrastructure and HFCVs at a high level of geographic and temporal resolution. To demonstrate the utility of STREET, two spatially and temporally resolved scenarios for hydrogen infrastructure are evaluated in a prototypical urban airshed (the South Coast Air Basin of California) using geographic information systems (GIS) data. The well-to-wheels (WTW) GHG emissions are quantified and the air quality is established using a detailed atmospheric chemistry and transport model followed by a comparison to a future gasoline scenario comprised of advanced ICE vehicles. One hydrogen scenario includes more renewable primary energy sources for hydrogen generation and the other includes more fossil fuel sources. The two scenarios encompass a variety of hydrogen generation, distribution, and fueling strategies. GHG emissions reductions range from 61 to 68% for both hydrogen scenarios in parallel with substantial improvements in urban air quality (e.g., reductions of 10 ppb in peak 8-h-averaged ozone and 6 mug/m(3) in 24-h-averaged particulate matter concentrations, particularly in regions of the airshed where concentrations are highest for the gasoline scenario

  5. Determining air quality and greenhouse gas impacts of hydrogen infrastructure and fuel cell vehicles.

    PubMed

    Stephens-Romero, Shane; Carreras-Sospedra, Marc; Brouwer, Jacob; Dabdub, Donald; Samuelsen, Scott

    2009-12-01

    Adoption of hydrogen infrastructure and hydrogen fuel cell vehicles (HFCVs) to replace gasoline internal combustion engine (ICE) vehicles has been proposed as a strategy to reduce criteria pollutant and greenhouse gas (GHG) emissions from the transportation sector and transition to fuel independence. However, it is uncertain (1) to what degree the reduction in criteria pollutants will impact urban air quality, and (2) how the reductions in pollutant emissions and concomitant urban air quality impacts compare to ultralow emission gasoline-powered vehicles projected for a future year (e.g., 2060). To address these questions, the present study introduces a "spatially and temporally resolved energy and environment tool" (STREET) to characterize the pollutant and GHG emissions associated with a comprehensive hydrogen supply infrastructure and HFCVs at a high level of geographic and temporal resolution. To demonstrate the utility of STREET, two spatially and temporally resolved scenarios for hydrogen infrastructure are evaluated in a prototypical urban airshed (the South Coast Air Basin of California) using geographic information systems (GIS) data. The well-to-wheels (WTW) GHG emissions are quantified and the air quality is established using a detailed atmospheric chemistry and transport model followed by a comparison to a future gasoline scenario comprised of advanced ICE vehicles. One hydrogen scenario includes more renewable primary energy sources for hydrogen generation and the other includes more fossil fuel sources. The two scenarios encompass a variety of hydrogen generation, distribution, and fueling strategies. GHG emissions reductions range from 61 to 68% for both hydrogen scenarios in parallel with substantial improvements in urban air quality (e.g., reductions of 10 ppb in peak 8-h-averaged ozone and 6 mug/m(3) in 24-h-averaged particulate matter concentrations, particularly in regions of the airshed where concentrations are highest for the gasoline scenario).

  6. Risk factors for increased BTEX exposure in four Australian cities.

    PubMed

    Hinwood, Andrea L; Rodriguez, Clemencia; Runnion, Tina; Farrar, Drew; Murray, Frank; Horton, Anthony; Glass, Deborah; Sheppeard, Vicky; Edwards, John W; Denison, Lynnette; Whitworth, Tom; Eiser, Chris; Bulsara, Max; Gillett, Rob W; Powell, Jenny; Lawson, S; Weeks, Ian; Galbally, Ian

    2007-01-01

    Benzene, toluene, ethylbenzene and xylenes (BTEX) are common volatile organic compounds (VOCs) found in urban airsheds. Elevated levels of VOCs have been reported in many airsheds at many locations, particularly those associated with industrial activity, wood heater use and heavy traffic. Exposure to some VOCs has been associated with health risks. There have been limited investigations into community exposures to BTEX using personal monitoring to elucidate the concentrations to which members of the community may be exposed and the main contributors to that exposure. In this cross sectional study we investigated BTEX exposure of 204 non-smoking, non-occupationally exposed people from four Australian cities. Each participant wore a passive BTEX sampler over 24h on five consecutive days in both winter and summer and completed an exposure source questionnaire for each season and a diary for each day of monitoring. The geometric mean (GM) and range of daily BTEX concentrations recorded for the study population were benzene 0.80 (0.04-23.8 ppb); toluene 2.83 (0.03-2120 ppb); ethylbenzene 0.49 (0.03-119 ppb); and xylenes 2.36 (0.04-697 ppb). A generalised linear model was used to investigate significant risk factors for increased BTEX exposure. Activities and locations found to increase personal exposure included vehicle repair and machinery use, refuelling of motor vehicles, being in an enclosed car park and time spent undertaking arts and crafts. A highly significant difference was found between the mean exposures in each of the four cities, which may be explained by differences in fuel composition, differences in the mix and density of industry, density of motor vehicles and air pollution meteorology. PMID:16837022

  7. Dataset Modelability by QSAR

    PubMed Central

    Golbraikh, Alexander; Muratov, Eugene; Fourches, Denis; Tropsha, Alexander

    2014-01-01

    We introduce a simple MODelability Index (MODI) that estimates the feasibility of obtaining predictive QSAR models (Correct Classification Rate above 0.7) for a binary dataset of bioactive compounds. MODI is defined as an activity class-weighted ratio of the number of the nearest neighbor pairs of compounds with the same activity class versus the total number of pairs. The MODI values were calculated for more than 100 datasets and the threshold of 0.65 was found to separate non-modelable from the modelable datasets. PMID:24251851

  8. Mathematical model of sarcoidosis

    PubMed Central

    Hao, Wenrui; Crouser, Elliott D.; Friedman, Avner

    2014-01-01

    Sarcoidosis is a disease involving abnormal collection of inflammatory cells forming nodules, called granulomas. Such granulomas occur in the lung and the mediastinal lymph nodes, in the heart, and in other vital and nonvital organs. The origin of the disease is unknown, and there are only limited clinical data on lung tissue of patients. No current model of sarcoidosis exists. In this paper we develop a mathematical model on the dynamics of the disease in the lung and use patients’ lung tissue data to validate the model. The model is used to explore potential treatments. PMID:25349384

  9. Models of Reality.

    SciTech Connect

    Brown-VanHoozer, S. A.

    1999-06-02

    Conscious awareness of our environment is based on a feedback loop comprised of sensory input transmitted to the central nervous system leading to construction of our ''model of the world,'' (Lewis et al, 1982). We then assimilate the neurological model at the unconscious level into information we can later consciously consider useful in identifying belief systems and behaviors for designing diverse systems. Thus, we can avoid potential problems based on our open-to-error perceived reality of the world. By understanding how our model of reality is organized, we allow ourselves to transcend content and develop insight into how effective choices and belief systems are generated through sensory derived processes. These are the processes which provide the designer the ability to meta model (build a model of a model) the user; consequently, matching the mental model of the user with that of the designer's and, coincidentally, forming rapport between the two participants. The information shared between the participants is neither assumed nor generalized, it is closer to equivocal; thus minimizing error through a sharing of each other's model of reality. How to identify individual mental mechanisms or processes, how to organize the individual strategies of these mechanisms into useful patterns, and to formulate these into models for success and knowledge based outcomes is the subject of the discussion that follows.

  10. Computer Modeling and Simulation

    SciTech Connect

    Pronskikh, V. S.

    2014-05-09

    Verification and validation of computer codes and models used in simulation are two aspects of the scientific practice of high importance and have recently been discussed by philosophers of science. While verification is predominantly associated with the correctness of the way a model is represented by a computer code or algorithm, validation more often refers to model’s relation to the real world and its intended use. It has been argued that because complex simulations are generally not transparent to a practitioner, the Duhem problem can arise for verification and validation due to their entanglement; such an entanglement makes it impossible to distinguish whether a coding error or model’s general inadequacy to its target should be blamed in the case of the model failure. I argue that in order to disentangle verification and validation, a clear distinction between computer modeling (construction of mathematical computer models of elementary processes) and simulation (construction of models of composite objects and processes by means of numerical experimenting with them) needs to be made. Holding on to that distinction, I propose to relate verification (based on theoretical strategies such as inferences) to modeling and validation, which shares the common epistemology with experimentation, to simulation. To explain reasons of their intermittent entanglement I propose a weberian ideal-typical model of modeling and simulation as roles in practice. I suggest an approach to alleviate the Duhem problem for verification and validation generally applicable in practice and based on differences in epistemic strategies and scopes

  11. Models of HERG gating.

    PubMed

    Bett, Glenna C L; Zhou, Qinlian; Rasmusson, Randall L

    2011-08-01

    HERG (Kv11.1, KCNH2) is a voltage-gated potassium channel with unique gating characteristics. HERG has fast voltage-dependent inactivation, relatively slow deactivation, and fast recovery from inactivation. This combination of gating kinetics makes study of HERG difficult without using mathematical models. Several HERG models have been developed, with fundamentally different organization. HERG is the molecular basis of I(Kr), which plays a critical role in repolarization. We programmed and compared five distinct HERG models. HERG gating cannot be adequately replicated using Hodgkin-Huxley type formulation. Using Markov models, a five-state model is required with three closed, one open, and one inactivated state, and a voltage-independent step between some of the closed states. A fundamental difference between models is the presence/absence of a transition directly from the proximal closed state to the inactivated state. The only models that effectively reproduce HERG data have no direct closed-inactivated transition, or have a closed-inactivated transition that is effectively zero compared to the closed-open transition, rendering the closed-inactivation transition superfluous. Our single-channel model demonstrates that channels can inactivate without conducting with a flickering or bursting open-state. The various models have qualitative and quantitative differences that are critical to accurate predictions of HERG behavior during repolarization, tachycardia, and premature depolarizations. PMID:21806931

  12. Modeling plant morphogenesis.

    PubMed

    Prusinkiewicz, Przemyslaw; Rolland-Lagan, Anne-Gaëlle

    2006-02-01

    Applications of computational techniques to developmental plant biology include the processing of experimental data and the construction of simulation models. Substantial progress has been made in these areas over the past few years. Complex image-processing techniques are used to integrate sequences of two-dimensional images into three-dimensional descriptions of development over time and to extract useful quantitative traits. Large amounts of data are integrated into empirical models of developing plant organs and entire plants. Mechanistic models link molecular-level phenomena with the resulting phenotypes. Several models shed light on the possible properties of active auxin transport and its role in plant morphogenesis. PMID:16376602

  13. Model Error Budgets

    NASA Technical Reports Server (NTRS)

    Briggs, Hugh C.

    2008-01-01

    An error budget is a commonly used tool in design of complex aerospace systems. It represents system performance requirements in terms of allowable errors and flows these down through a hierarchical structure to lower assemblies and components. The requirements may simply be 'allocated' based upon heuristics or experience, or they may be designed through use of physics-based models. This paper presents a basis for developing an error budget for models of the system, as opposed to the system itself. The need for model error budgets arises when system models are a principle design agent as is increasingly more common for poorly testable high performance space systems.

  14. Lightning return stroke models

    NASA Technical Reports Server (NTRS)

    Lin, Y. T.; Uman, M. A.; Standler, R. B.

    1980-01-01

    We test the two most commonly used lightning return stroke models, Bruce-Golde and transmission line, against subsequent stroke electric and magnetic field wave forms measured simultaneously at near and distant stations and show that these models are inadequate to describe the experimental data. We then propose a new return stroke model that is physically plausible and that yields good approximations to the measured two-station fields. Using the new model, we derive return stroke charge and current statistics for about 100 subsequent strokes.

  15. Modeling plant morphogenesis.

    PubMed

    Prusinkiewicz, Przemyslaw; Rolland-Lagan, Anne-Gaëlle

    2006-02-01

    Applications of computational techniques to developmental plant biology include the processing of experimental data and the construction of simulation models. Substantial progress has been made in these areas over the past few years. Complex image-processing techniques are used to integrate sequences of two-dimensional images into three-dimensional descriptions of development over time and to extract useful quantitative traits. Large amounts of data are integrated into empirical models of developing plant organs and entire plants. Mechanistic models link molecular-level phenomena with the resulting phenotypes. Several models shed light on the possible properties of active auxin transport and its role in plant morphogenesis.

  16. Particle bed reactor modeling

    NASA Technical Reports Server (NTRS)

    Sapyta, Joe; Reid, Hank; Walton, Lew

    1993-01-01

    The topics are presented in viewgraph form and include the following: particle bed reactor (PBR) core cross section; PBR bleed cycle; fuel and moderator flow paths; PBR modeling requirements; characteristics of PBR and nuclear thermal propulsion (NTP) modeling; challenges for PBR and NTP modeling; thermal hydraulic computer codes; capabilities for PBR/reactor application; thermal/hydralic codes; limitations; physical correlations; comparison of predicted friction factor and experimental data; frit pressure drop testing; cold frit mask factor; decay heat flow rate; startup transient simulation; and philosophy of systems modeling.

  17. Photovoltaic array performance model.

    SciTech Connect

    Kratochvil, Jay A.; Boyson, William Earl; King, David L.

    2004-08-01

    This document summarizes the equations and applications associated with the photovoltaic array performance model developed at Sandia National Laboratories over the last twelve years. Electrical, thermal, and optical characteristics for photovoltaic modules are included in the model, and the model is designed to use hourly solar resource and meteorological data. The versatility and accuracy of the model has been validated for flat-plate modules (all technologies) and for concentrator modules, as well as for large arrays of modules. Applications include system design and sizing, 'translation' of field performance measurements to standard reporting conditions, system performance optimization, and real-time comparison of measured versus expected system performance.

  18. Modelling approaches in biomechanics.

    PubMed Central

    Alexander, R McN

    2003-01-01

    Conceptual, physical and mathematical models have all proved useful in biomechanics. Conceptual models, which have been used only occasionally, clarify a point without having to be constructed physically or analysed mathematically. Some physical models are designed to demonstrate a proposed mechanism, for example the folding mechanisms of insect wings. Others have been used to check the conclusions of mathematical modelling. However, others facilitate observations that would be difficult to make on real organisms, for example on the flow of air around the wings of small insects. Mathematical models have been used more often than physical ones. Some of them are predictive, designed for example to calculate the effects of anatomical changes on jumping performance, or the pattern of flow in a 3D assembly of semicircular canals. Others seek an optimum, for example the best possible technique for a high jump. A few have been used in inverse optimization studies, which search for variables that are optimized by observed patterns of behaviour. Mathematical models range from the extreme simplicity of some models of walking and running, to the complexity of models that represent numerous body segments and muscles, or elaborate bone shapes. The simpler the model, the clearer it is which of its features is essential to the calculated effect. PMID:14561333

  19. Wind power prediction models

    NASA Technical Reports Server (NTRS)

    Levy, R.; Mcginness, H.

    1976-01-01

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

  20. DISJUNCTIVE NORMAL SHAPE MODELS

    PubMed Central

    Ramesh, Nisha; Mesadi, Fitsum; Cetin, Mujdat; Tasdizen, Tolga

    2016-01-01

    A novel implicit parametric shape model is proposed for segmentation and analysis of medical images. Functions representing the shape of an object can be approximated as a union of N polytopes. Each polytope is obtained by the intersection of M half-spaces. The shape function can be approximated as a disjunction of conjunctions, using the disjunctive normal form. The shape model is initialized using seed points defined by the user. We define a cost function based on the Chan-Vese energy functional. The model is differentiable, hence, gradient based optimization algorithms are used to find the model parameters. PMID:27403233

  1. Multifamily Envelope Leakage Model

    SciTech Connect

    Faakye, O.; Griffiths, D.

    2015-05-01

    The objective of the 2013 research project was to develop the model for predicting fully guarded test results (FGT), using unguarded test data and specific building features of apartment units. The model developed has a coefficient of determination R2 value of 0.53 with a root mean square error (RMSE) of 0.13. Both statistical metrics indicate that the model is relatively strong. When tested against data that was not included in the development of the model, prediction accuracy was within 19%, which is reasonable given that seasonal differences in blower door measurements can vary by as much as 25%.

  2. Models of HERG Gating

    PubMed Central

    Bett, Glenna C.L.; Zhou, Qinlian; Rasmusson, Randall L.

    2011-01-01

    HERG (Kv11.1, KCNH2) is a voltage-gated potassium channel with unique gating characteristics. HERG has fast voltage-dependent inactivation, relatively slow deactivation, and fast recovery from inactivation. This combination of gating kinetics makes study of HERG difficult without using mathematical models. Several HERG models have been developed, with fundamentally different organization. HERG is the molecular basis of IKr, which plays a critical role in repolarization. We programmed and compared five distinct HERG models. HERG gating cannot be adequately replicated using Hodgkin-Huxley type formulation. Using Markov models, a five-state model is required with three closed, one open, and one inactivated state, and a voltage-independent step between some of the closed states. A fundamental difference between models is the presence/absence of a transition directly from the proximal closed state to the inactivated state. The only models that effectively reproduce HERG data have no direct closed-inactivated transition, or have a closed-inactivated transition that is effectively zero compared to the closed-open transition, rendering the closed-inactivation transition superfluous. Our single-channel model demonstrates that channels can inactivate without conducting with a flickering or bursting open-state. The various models have qualitative and quantitative differences that are critical to accurate predictions of HERG behavior during repolarization, tachycardia, and premature depolarizations. PMID:21806931

  3. Radiation Environment Modeling for Spacecraft Design: New Model Developments

    NASA Technical Reports Server (NTRS)

    Barth, Janet; Xapsos, Mike; Lauenstein, Jean-Marie; Ladbury, Ray

    2006-01-01

    A viewgraph presentation on various new space radiation environment models for spacecraft design is described. The topics include: 1) The Space Radiatio Environment; 2) Effects of Space Environments on Systems; 3) Space Radiatio Environment Model Use During Space Mission Development and Operations; 4) Space Radiation Hazards for Humans; 5) "Standard" Space Radiation Environment Models; 6) Concerns about Standard Models; 7) Inadequacies of Current Models; 8) Development of New Models; 9) New Model Developments: Proton Belt Models; 10) Coverage of New Proton Models; 11) Comparison of TPM-1, PSB97, AP-8; 12) New Model Developments: Electron Belt Models; 13) Coverage of New Electron Models; 14) Comparison of "Worst Case" POLE, CRESELE, and FLUMIC Models with the AE-8 Model; 15) New Model Developments: Galactic Cosmic Ray Model; 16) Comparison of NASA, MSU, CIT Models with ACE Instrument Data; 17) New Model Developmemts: Solar Proton Model; 18) Comparison of ESP, JPL91, KIng/Stassinopoulos, and PSYCHIC Models; 19) New Model Developments: Solar Heavy Ion Model; 20) Comparison of CREME96 to CREDO Measurements During 2000 and 2002; 21) PSYCHIC Heavy ion Model; 22) Model Standardization; 23) Working Group Meeting on New Standard Radiation Belt and Space Plasma Models; and 24) Summary.

  4. Groundwater Model Validation

    SciTech Connect

    Ahmed E. Hassan

    2006-01-24

    Models have an inherent uncertainty. The difficulty in fully characterizing the subsurface environment makes uncertainty an integral component of groundwater flow and transport models, which dictates the need for continuous monitoring and improvement. Building and sustaining confidence in closure decisions and monitoring networks based on models of subsurface conditions require developing confidence in the models through an iterative process. The definition of model validation is postulated as a confidence building and long-term iterative process (Hassan, 2004a). Model validation should be viewed as a process not an end result. Following Hassan (2004b), an approach is proposed for the validation process of stochastic groundwater models. The approach is briefly summarized herein and detailed analyses of acceptance criteria for stochastic realizations and of using validation data to reduce input parameter uncertainty are presented and applied to two case studies. During the validation process for stochastic models, a question arises as to the sufficiency of the number of acceptable model realizations (in terms of conformity with validation data). Using a hierarchical approach to make this determination is proposed. This approach is based on computing five measures or metrics and following a decision tree to determine if a sufficient number of realizations attain satisfactory scores regarding how they represent the field data used for calibration (old) and used for validation (new). The first two of these measures are applied to hypothetical scenarios using the first case study and assuming field data consistent with the model or significantly different from the model results. In both cases it is shown how the two measures would lead to the appropriate decision about the model performance. Standard statistical tests are used to evaluate these measures with the results indicating they are appropriate measures for evaluating model realizations. The use of validation

  5. Why business models matter.

    PubMed

    Magretta, Joan

    2002-05-01

    "Business model" was one of the great buzz-words of the Internet boom. A company didn't need a strategy, a special competence, or even any customers--all it needed was a Web-based business model that promised wild profits in some distant, ill-defined future. Many people--investors, entrepreneurs, and executives alike--fell for the fantasy and got burned. And as the inevitable counterreaction played out, the concept of the business model fell out of fashion nearly as quickly as the .com appendage itself. That's a shame. As Joan Magretta explains, a good business model remains essential to every successful organization, whether it's a new venture or an established player. To help managers apply the concept successfully, she defines what a business model is and how it complements a smart competitive strategy. Business models are, at heart, stories that explain how enterprises work. Like a good story, a robust business model contains precisely delineated characters, plausible motivations, and a plot that turns on an insight about value. It answers certain questions: Who is the customer? How do we make money? What underlying economic logic explains how we can deliver value to customers at an appropriate cost? Every viable organization is built on a sound business model, but a business model isn't a strategy, even though many people use the terms interchangeably. Business models describe, as a system, how the pieces of a business fit together. But they don't factor in one critical dimension of performance: competition. That's the job of strategy. Illustrated with examples from companies like American Express, EuroDisney, WalMart, and Dell Computer, this article clarifies the concepts of business models and strategy, which are fundamental to every company's performance.

  6. Biosphere Process Model Report

    SciTech Connect

    J. Schmitt

    2000-05-25

    To evaluate the postclosure performance of a potential monitored geologic repository at Yucca Mountain, a Total System Performance Assessment (TSPA) will be conducted. Nine Process Model Reports (PMRs), including this document, are being developed to summarize the technical basis for each of the process models supporting the TSPA model. These reports cover the following areas: (1) Integrated Site Model; (2) Unsaturated Zone Flow and Transport; (3) Near Field Environment; (4) Engineered Barrier System Degradation, Flow, and Transport; (5) Waste Package Degradation; (6) Waste Form Degradation; (7) Saturated Zone Flow and Transport; (8) Biosphere; and (9) Disruptive Events. Analysis/Model Reports (AMRs) contain the more detailed technical information used to support TSPA and the PMRs. The AMRs consists of data, analyses, models, software, and supporting documentation that will be used to defend the applicability of each process model for evaluating the postclosure performance of the potential Yucca Mountain repository system. This documentation will ensure the traceability of information from its source through its ultimate use in the TSPA-Site Recommendation (SR) and in the National Environmental Policy Act (NEPA) analysis processes. The objective of the Biosphere PMR is to summarize (1) the development of the biosphere model, and (2) the Biosphere Dose Conversion Factors (BDCFs) developed for use in TSPA. The Biosphere PMR does not present or summarize estimates of potential radiation doses to human receptors. Dose calculations are performed as part of TSPA and will be presented in the TSPA documentation. The biosphere model is a component of the process to evaluate postclosure repository performance and regulatory compliance for a potential monitored geologic repository at Yucca Mountain, Nevada. The biosphere model describes those exposure pathways in the biosphere by which radionuclides released from a potential repository could reach a human receptor

  7. Bayesian Data-Model Fit Assessment for Structural Equation Modeling

    ERIC Educational Resources Information Center

    Levy, Roy

    2011-01-01

    Bayesian approaches to modeling are receiving an increasing amount of attention in the areas of model construction and estimation in factor analysis, structural equation modeling (SEM), and related latent variable models. However, model diagnostics and model criticism remain relatively understudied aspects of Bayesian SEM. This article describes…

  8. Spiral model pilot project information model

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The objective was an evaluation of the Spiral Model (SM) development approach to allow NASA Marshall to develop an experience base of that software management methodology. A discussion is presented of the Information Model (IM) that was used as part of the SM methodology. A key concept of the SM is the establishment of an IM to be used by management to track the progress of a project. The IM is the set of metrics that is to be measured and reported throughout the life of the project. These metrics measure both the product and the process to ensure the quality of the final delivery item and to ensure the project met programmatic guidelines. The beauty of the SM, along with the IM, is the ability to measure not only the correctness of the specification and implementation of the requirements but to also obtain a measure of customer satisfaction.

  9. The IAEA Coordinated Research Program on HTGR Uncertainty Analysis: Phase I Status and Initial Results

    SciTech Connect

    Strydom, Gerhard; Bostelmann, Friederike; Ivanov, Kostadin

    2014-10-01

    required confidence level. In order to address uncertainty propagation in analysis and methods in the HTGR community the IAEA initiated a Coordinated Research Project (CRP) on the HTGR Uncertainty Analysis in Modelling (UAM) that officially started in 2013. Although this project focuses specifically on the peculiarities of HTGR designs and its simulation requirements, many lessons can be learned from the LWR community and the significant progress already made towards a consistent methodology uncertainty analysis. In the case of LWRs the NRC has already in 1988 amended 10 CFR 50.46 to allow best-estimate (plus uncertainties) calculations of emergency core cooling system performance. The Nuclear Energy Agency (NEA) of the Organization for Economic Co-operation and Development (OECD) also established an Expert Group on "Uncertainty Analysis in Modelling" which finally led to the definition of the "Benchmark for Uncertainty Analysis in Modelling (UAM) for Design, Operation and Safety Analysis of LWRs". The CRP on HTGR UAM will follow as far as possible the on-going OECD Light Water Reactor UAM benchmark activity.

  10. Automated Student Model Improvement

    ERIC Educational Resources Information Center

    Koedinger, Kenneth R.; McLaughlin, Elizabeth A.; Stamper, John C.

    2012-01-01

    Student modeling plays a critical role in developing and improving instruction and instructional technologies. We present a technique for automated improvement of student models that leverages the DataShop repository, crowd sourcing, and a version of the Learning Factors Analysis algorithm. We demonstrate this method on eleven educational…

  11. Modeling Antibody Diversity.

    ERIC Educational Resources Information Center

    Baker, William P.; Moore, Cathy Ronstadt

    1998-01-01

    Understanding antibody structure and function is difficult for many students. The rearrangement of constant and variable regions during antibody differentiation can be effectively simulated using a paper model. Describes a hands-on laboratory exercise which allows students to model antibody diversity using readily available resources. (PVD)

  12. Canister Model, Systems Analysis

    1993-09-29

    This packges provides a computer simulation of a systems model for packaging nuclear waste and spent nuclear fuel in canisters. The canister model calculates overall programmatic cost, number of canisters, and fuel and waste inventories for the Idaho Chemical Processing Plant (other initial conditions can be entered).

  13. Earth and ocean modeling

    NASA Technical Reports Server (NTRS)

    Knezovich, F. M.

    1976-01-01

    A modular structured system of computer programs is presented utilizing earth and ocean dynamical data keyed to finitely defined parameters. The model is an assemblage of mathematical algorithms with an inherent capability of maturation with progressive improvements in observational data frequencies, accuracies and scopes. The Eom in its present state is a first-order approach to a geophysical model of the earth's dynamics.

  14. Fictional models in science

    NASA Astrophysics Data System (ADS)

    Morrison, Margaret

    2014-02-01

    When James Clerk Maxwell set out his famous equations 150 years ago, his model of electromagnetism included a piece of pure fiction: an invisible, all-pervasive "aether" made up of elastic vortices separated by electric charges. Margaret Morrison explores how this and other "fictional" models shape science.

  15. Modeling Water Filtration

    ERIC Educational Resources Information Center

    Parks, Melissa

    2014-01-01

    Model-eliciting activities (MEAs) are not new to those in engineering or mathematics, but they were new to Melissa Parks. Model-eliciting activities are simulated real-world problems that integrate engineering, mathematical, and scientific thinking as students find solutions for specific scenarios. During this process, students generate solutions…

  16. Dasymetric Modeling and Uncertainty

    PubMed Central

    Nagle, Nicholas N.; Buttenfield, Barbara P.; Leyk, Stefan; Speilman, Seth

    2014-01-01

    Dasymetric models increase the spatial resolution of population data by incorporating related ancillary data layers. The role of uncertainty in dasymetric modeling has not been fully addressed as of yet. Uncertainty is usually present because most population data are themselves uncertain, and/or the geographic processes that connect population and the ancillary data layers are not precisely known. A new dasymetric methodology - the Penalized Maximum Entropy Dasymetric Model (P-MEDM) - is presented that enables these sources of uncertainty to be represented and modeled. The P-MEDM propagates uncertainty through the model and yields fine-resolution population estimates with associated measures of uncertainty. This methodology contains a number of other benefits of theoretical and practical interest. In dasymetric modeling, researchers often struggle with identifying a relationship between population and ancillary data layers. The PEDM model simplifies this step by unifying how ancillary data are included. The P-MEDM also allows a rich array of data to be included, with disparate spatial resolutions, attribute resolutions, and uncertainties. While the P-MEDM does not necessarily produce more precise estimates than do existing approaches, it does help to unify how data enter the dasymetric model, it increases the types of data that may be used, and it allows geographers to characterize the quality of their dasymetric estimates. We present an application of the P-MEDM that includes household-level survey data combined with higher spatial resolution data such as from census tracts, block groups, and land cover classifications. PMID:25067846

  17. Connectionist Modelling and Education.

    ERIC Educational Resources Information Center

    Evers, Colin W.

    2000-01-01

    Provides a detailed, technical introduction to the state of cognitive science research, in particular the rise of the "new cognitive science," especially artificial neural net (ANN) models. Explains one influential ANN model and describes diverse applications and their implications for education. (EV)

  18. Unitary Response Regression Models

    ERIC Educational Resources Information Center

    Lipovetsky, S.

    2007-01-01

    The dependent variable in a regular linear regression is a numerical variable, and in a logistic regression it is a binary or categorical variable. In these models the dependent variable has varying values. However, there are problems yielding an identity output of a constant value which can also be modelled in a linear or logistic regression with…

  19. Animal models for osteoporosis

    NASA Technical Reports Server (NTRS)

    Turner, R. T.; Maran, A.; Lotinun, S.; Hefferan, T.; Evans, G. L.; Zhang, M.; Sibonga, J. D.

    2001-01-01

    Animal models will continue to be important tools in the quest to understand the contribution of specific genes to establishment of peak bone mass and optimal bone architecture, as well as the genetic basis for a predisposition toward accelerated bone loss in the presence of co-morbidity factors such as estrogen deficiency. Existing animal models will continue to be useful for modeling changes in bone metabolism and architecture induced by well-defined local and systemic factors. However, there is a critical unfulfilled need to develop and validate better animal models to allow fruitful investigation of the interaction of the multitude of factors which precipitate senile osteoporosis. Well characterized and validated animal models that can be recommended for investigation of the etiology, prevention and treatment of several forms of osteoporosis have been listed in Table 1. Also listed are models which are provisionally recommended. These latter models have potential but are inadequately characterized, deviate significantly from the human response, require careful choice of strain or age, or are not practical for most investigators to adopt. It cannot be stressed strongly enough that the enormous potential of laboratory animals as models for osteoporosis can only be realized if great care is taken in the choice of an appropriate species, age, experimental design, and measurements. Poor choices will results in misinterpretation of results which ultimately can bring harm to patients who suffer from osteoporosis by delaying advancement of knowledge.

  20. Models and Metaphors

    ERIC Educational Resources Information Center

    Ivie, Stanley D.

    2007-01-01

    Humanity delights in spinning conceptual models of the world. These models, in turn, mirror their respective root metaphors. Three root metaphors--spiritual, organic, and mechanical--have dominated western thought. The spiritual metaphor runs from Plato, through Hegel, and connects with Montessori. The organic metaphor extends from Aristotle,…

  1. Pathological Gambling: Psychiatric Models

    ERIC Educational Resources Information Center

    Westphal, James R.

    2008-01-01

    Three psychiatric conceptual models: addictive, obsessive-compulsive spectrum and mood spectrum disorder have been proposed for pathological gambling. The objectives of this paper are to (1) evaluate the evidence base from the most recent reviews of each model, (2) update the evidence through 2007 and (3) summarize the status of the evidence for…

  2. Evaluating Causal Models.

    ERIC Educational Resources Information Center

    Watt, James H., Jr.

    Pointing out that linear causal models can organize the interrelationships of a large number of variables, this paper contends that such models are particularly useful to mass communication research, which must by necessity deal with complex systems of variables. The paper first outlines briefly the philosophical requirements for establishing a…

  3. Modeling Carbon Exchange

    NASA Technical Reports Server (NTRS)

    Sellers, Piers

    2012-01-01

    Model results will be reviewed to assess different methods for bounding the terrestrial role in the global carbon cycle. It is proposed that a series of climate model runs could be scoped that would tighten the limits on the "missing sink" of terrestrial carbon and could also direct future satellite image analyses to search for its geographical location and understand its seasonal dynamics.

  4. Using Models Effectively

    ERIC Educational Resources Information Center

    Eichinger, John

    2005-01-01

    Models are crucial to science teaching and learning, yet they can create unforeseen and overlooked challenges for students and teachers. For example, consider the time-tested clay volcano that relies on a vinegar and-baking-soda mixture for its "eruption." Based on a classroom demonstration of that geologic model, elementary students may interpret…

  5. Multilevel Mixture Factor Models

    ERIC Educational Resources Information Center

    Varriale, Roberta; Vermunt, Jeroen K.

    2012-01-01

    Factor analysis is a statistical method for describing the associations among sets of observed variables in terms of a small number of underlying continuous latent variables. Various authors have proposed multilevel extensions of the factor model for the analysis of data sets with a hierarchical structure. These Multilevel Factor Models (MFMs)…

  6. Modelling extended chromospheres

    NASA Technical Reports Server (NTRS)

    Linsky, J. L.

    1986-01-01

    Attention is given to the concept that the warm, partially ionized plasma (presently called chromosphere) associated with such stars as Alpha Boo and Rho Per extends outwards at least several photospheric radii. Calculations are presented for the Mg II K line in light of two input model atmospheres. Specific predictions are deduced from the results obtained by each of the two models.

  7. Model-Based Reasoning

    ERIC Educational Resources Information Center

    Ifenthaler, Dirk; Seel, Norbert M.

    2013-01-01

    In this paper, there will be a particular focus on mental models and their application to inductive reasoning within the realm of instruction. A basic assumption of this study is the observation that the construction of mental models and related reasoning is a slowly developing capability of cognitive systems that emerges effectively with proper…

  8. A night sky model.

    NASA Astrophysics Data System (ADS)

    Erpylev, N. P.; Smirnov, M. A.; Bagrov, A. V.

    A night sky model is proposed. It includes different components of light polution, such as solar twilight, moon scattered light, zodiacal light, Milky Way, air glow and artificial light pollution. The model is designed for calculating the efficiency of astronomical installations.

  9. Solar Atmosphere Models

    NASA Astrophysics Data System (ADS)

    Rutten, R. J.

    2002-12-01

    This contribution honoring Kees de Jager's 80th birthday is a review of "one-dimensional" solar atmosphere modeling that followed on the initial "Utrecht Reference Photosphere" of Heintze, Hubenet & de Jager (1964). My starting point is the Bilderberg conference, convened by de Jager in 1967 at the time when NLTE radiative transfer theory became mature. The resulting Bilderberg model was quickly superseded by the HSRA and later by the VAL-FAL sequence of increasingly sophisticated NLTE continuum-fitting models from Harvard. They became the "standard models" of solar atmosphere physics, but Holweger's relatively simple LTE line-fitting model still persists as a favorite of solar abundance determiners. After a brief model inventory I discuss subsequent work on the major modeling issues (coherency, NLTE, dynamics) listed as to-do items by de Jager in 1968. The present conclusion is that one-dimensional modeling recovers Schwarzschild's (1906) finding that the lower solar atmosphere is grosso modo in radiative equilibrium. This is a boon for applications regarding the solar atmosphere as one-dimensional stellar example - but the real sun, including all the intricate phenomena that now constitute the mainstay of solar physics, is vastly more interesting.

  10. Stereolithography models. Final report

    SciTech Connect

    Smith, R.E.

    1995-03-01

    This report describes the first stereolithographic models made, which proved in a new release of ProEngineer software (Parametric Technologies, or PTC) and 3D Systems (Valencia, California) software for the SLA 250 machine. They are a model of benzene and the {alpha}-carbon backbone of the variable region of an antibody.

  11. Mathematical models of hysteresis

    SciTech Connect

    1998-08-01

    The ongoing research has largely been focused on the development of mathematical models of hysteretic nonlinearities with nonlocal memories. The distinct feature of these nonlinearities is that their current states depend on past histories of input variations. It turns out that memories of hysteretic nonlinearities are quite selective. Indeed, experiments show that only some past input extrema (not the entire input variations) leave their marks upon future states of hysteretic nonlinearities. Thus special mathematical tools are needed in order to describe nonlocal selective memories of hysteretic nonlinearities. The origin of such tools can be traced back to the landmark paper of Preisach. Their research has been primarily concerned with Preisach-type models of hysteresis. All these models have a common generic feature; they are constructed as superpositions of simplest hysteretic nonlinearities-rectangular loops. During the past four years, the study has been by and large centered around the following topics: (1) further development of Scalar and vector Preisach-type models of hysteresis; (2) experimental testing of Preisach-type models of hysteresis; (3) development of new models for viscosity (aftereffect) in hysteretic systems; (4) development of mathematical models for superconducting hysteresis in the case of gradual resistive transitions; (5) software implementation of Preisach-type models of hysteresis; and (6) development of new ideas which have emerged in the course of the research work. The author briefly describes the main scientific results obtained in the areas outlined above.

  12. Dynamic Eye Model.

    ERIC Educational Resources Information Center

    Journal of Science and Mathematics Education in Southeast Asia, 1981

    1981-01-01

    Instructions (with diagrams and parts list) are provided for constructing an eye model with a pliable lens made from a plastic bottle which can vary its convexity to accommodate changing positions of an object being viewed. Also discusses concepts which the model can assist in developing. (Author/SK)

  13. Model for Coastal Restoration

    SciTech Connect

    Thom, Ronald M.; Judd, Chaeli

    2007-07-27

    Successful restoration of wetland habitats depends on both our understanding of our system and our ability to characterize it. By developing a conceptual model, looking at different spatial scales and integrating diverse data streams: GIS datasets and NASA products, we were able to develop a dynamic model for site prioritization based on both qualitative and quantitative relationships found in the coastal environment.

  14. Modelling Hadronic Matter

    NASA Astrophysics Data System (ADS)

    Menezes, Débora P.

    2016-04-01

    Hadron physics stands somewhere in the diffuse intersection between nuclear and particle physics and relies largely on the use of models. Historically, around 1930, the first nuclear physics models known as the liquid drop model and the semi-empirical mass formula established the grounds for the study of nuclei properties and nuclear structure. These two models are parameter dependent. Nowadays, around 500 hundred non-relativistic (Skyrme-type) and relativistic models are available in the literature and largely used and the vast majority are parameter dependent models. In this review I discuss some of the shortcomings of using non-relativistic models and the advantages of using relativistic ones when applying them to describe hadronic matter. I also show possible applications of relativistic models to physical situations that cover part of the QCD phase diagram: I mention how the description of compact objects can be done, how heavy-ion collisions can be investigated and particle fractions obtained and show the relation between liquid-gas phase transitions and the pasta phase.

  15. Models in Biology.

    ERIC Educational Resources Information Center

    Flannery, Maura C.

    1997-01-01

    Addresses the most popular models currently being chosen for biological research and the reasons behind those choices. Among the current favorites are zebra fish, fruit flies, mice, monkeys, and yeast. Concludes with a brief examination of the ethical issues involved, and why some animals may need to be replaced in research with model systems.…

  16. Anticipatory model of cavitation

    NASA Astrophysics Data System (ADS)

    Kercel, Stephen W.; Allgood, Glenn O.; Dress, William B.; Hylton, James O.

    1999-03-01

    The Anticipatory System (AS) formalism developed by Robert Rosen provides some insight into the problem of embedding intelligent behavior in machines. AS emulates the anticipatory behavior of biological systems. AS bases its behavior on its expectations about the near future and those expectations are modified as the system gains experience. The expectation is based on an internal model that is drawn from an appeal to physical reality. To be adaptive, the model must be able to update itself. To be practical, the model must run faster than real-time. The need for a physical model and the requirement that the model execute at extreme speeds, has held back the application of AS to practical problems. Two recent advances make it possible to consider the use of AS for practical intelligent sensors. First, advances in transducer technology make it possible to obtain previously unavailable data from which a model can be derived. For example, acoustic emissions (AE) can be fed into a Bayesian system identifier that enables the separation of a weak characterizing signal, such as the signature of pump cavitation precursors, from a strong masking signal, such as a pump vibration feature. The second advance is the development of extremely fast, but inexpensive, digital signal processing hardware on which it is possible to run an adaptive Bayesian-derived model faster than real-time. This paper reports the investigation of an AS using a model of cavitation based on hydrodynamic principles and Bayesian analysis of data from high-performance AE sensors.

  17. A Model for Implementation.

    ERIC Educational Resources Information Center

    O'Connor-Petruso, Sharon Anne

    2003-01-01

    Describes the Constructural Multi-Modalities Model for MST (math, science, and technology) Inquiry Units. The MST Model uses an interdisciplinary and constructivist approach and allows teachers to create lesson plans that: integrate MST in tandem; adhere to local, state, and national standards; and actively engage students' differentiated learning…

  18. Video Self-Modeling

    ERIC Educational Resources Information Center

    Buggey, Tom; Ogle, Lindsey

    2012-01-01

    Video self-modeling (VSM) first appeared on the psychology and education stage in the early 1970s. The practical applications of VSM were limited by lack of access to tools for editing video, which is necessary for almost all self-modeling videos. Thus, VSM remained in the research domain until the advent of camcorders and VCR/DVD players and,…

  19. Model State Efforts.

    ERIC Educational Resources Information Center

    Morgan, Gwen

    Models of state involvement in training child care providers are briefly discussed and the employers' role in training is explored. Six criteria for states that are taken as models are identified, and four are described. Various state activities are described for each criterion. It is noted that little is known about employer and other private…

  20. Modeling HIV Cure

    NASA Astrophysics Data System (ADS)

    Perelson, Alan; Conway, Jessica; Cao, Youfang

    A large effort is being made to find a means to cure HIV infection. I will present a dynamical model of post-treatment control (PTC) or ``functional cure'' of HIV-infection. Some patients treated with suppressive antiviral therapy have been taken off of therapy and then spontaneously control HIV infection such that the amount of virus in the circulation is maintained undetectable by clinical assays for years. The model explains PTC occurring in some patients by having a parameter regime in which the model exhibits bistability, with both a low and high steady state viral load being stable. The model makes a number of predictions about how to attain the low PTC steady state. Bistability in this model depends upon the immune response becoming exhausted when over stimulated. I will also present a generalization of the model in which immunotherapy can be used to reverse immune exhaustion and compare model predictions with experiments in SIV infected macaques given immunotherapy and then taken off of antiretroviral therapy. Lastly, if time permits, I will discuss one of the hurdles to true HIV eradication, latently infected cells, and present clinical trial data and a new model addressing pharmacological means of flushing out the latent reservoir. Supported by NIH Grants AI028433 and OD011095.

  1. Symposium on ID Models.

    ERIC Educational Resources Information Center

    Silber, Kenneth H., Ed.

    1980-01-01

    Presents papers on four different instructional development models currently in use either in a university or a business setting. All phases of systematic development are covered, including project selection, production, implementation, performance analysis, constraints, and unusual features that distinguish each model. References are listed. (BK)

  2. Math, Science, and Models

    ERIC Educational Resources Information Center

    Weinburgh, Molly; Silva, Cecilia

    2011-01-01

    For the past five summers, the authors have taught summer school to recent immigrants and refugees. Their experiences with these fourth-grade English language learners (ELL) have taught them the value of using models to build scientific and mathematical concepts. In this article, they describe the use of different forms of 2- and 3-D models to…

  3. Dual-Schemata Model

    NASA Astrophysics Data System (ADS)

    Taniguchi, Tadahiro; Sawaragi, Tetsuo

    In this paper, a new machine-learning method, called Dual-Schemata model, is presented. Dual-Schemata model is a kind of self-organizational machine learning methods for an autonomous robot interacting with an unknown dynamical environment. This is based on Piaget's Schema model, that is a classical psychological model to explain memory and cognitive development of human beings. Our Dual-Schemata model is developed as a computational model of Piaget's Schema model, especially focusing on sensori-motor developing period. This developmental process is characterized by a couple of two mutually-interacting dynamics; one is a dynamics formed by assimilation and accommodation, and the other dynamics is formed by equilibration and differentiation. By these dynamics schema system enables an agent to act well in a real world. This schema's differentiation process corresponds to a symbol formation process occurring within an autonomous agent when it interacts with an unknown, dynamically changing environment. Experiment results obtained from an autonomous facial robot in which our model is embedded are presented; an autonomous facial robot becomes able to chase a ball moving in various ways without any rewards nor teaching signals from outside. Moreover, emergence of concepts on the target movements within a robot is shown and discussed in terms of fuzzy logics on set-subset inclusive relationships.

  4. Modeling for Insights

    SciTech Connect

    Jacob J. Jacobson; Gretchen Matthern

    2007-04-01

    System Dynamics is a computer-aided approach to evaluating the interrelationships of different components and activities within complex systems. Recently, System Dynamics models have been developed in areas such as policy design, biological and medical modeling, energy and the environmental analysis, and in various other areas in the natural and social sciences. The real power of System Dynamic modeling is gaining insights into total system behavior as time, and system parameters are adjusted and the effects are visualized in real time. System Dynamic models allow decision makers and stakeholders to explore long-term behavior and performance of complex systems, especially in the context of dynamic processes and changing scenarios without having to wait decades to obtain field data or risk failure if a poor management or design approach is used. The Idaho National Laboratory recently has been developing a System Dynamic model of the US Nuclear Fuel Cycle. The model is intended to be used to identify and understand interactions throughout the entire nuclear fuel cycle and suggest sustainable development strategies. This paper describes the basic framework of the current model and presents examples of useful insights gained from the model thus far with respect to sustainable development of nuclear power.

  5. SOSS ICN Model Validation

    NASA Technical Reports Server (NTRS)

    Zhu, Zhifan

    2016-01-01

    Under the NASA-KAIA-KARI ATM research collaboration agreement, SOSS ICN Model has been developed for Incheon International Airport. This presentation describes the model validation work in the project. The presentation will show the results and analysis of the validation.

  6. Animal models of candidiasis.

    PubMed

    Clancy, Cornelius J; Cheng, Shaoji; Nguyen, Minh Hong

    2009-01-01

    Animal models are powerful tools to study the pathogenesis of diverse types of candidiasis. Murine models are particularly attractive because of cost, ease of handling, technical feasibility, and experience with their use. In this chapter, we describe methods for two of the most popular murine models of disease caused by Candida albicans. In an intravenously disseminated candidiasis (DC) model, immunocompetent mice are infected by lateral tail vein injections of a C. albicans suspension. Endpoints include mortality, tissue burdens of infection (most importantly in the kidneys, although spleens and livers are sometimes also assessed), and histopathology of infected organs. In a model of oral/esophageal candidiasis, mice are immunosuppressed with cortisone acetate and inoculated in the oral cavities using swabs saturated with a C. albicans suspension. Since mice do not die from oral candidiasis in this model, endpoints are tissue burden of infection and histopathology. The DC and oral/esophageal models are most commonly used for studies of C. albicans virulence, in which the disease-causing ability of a mutant strain is compared with an isogenic parent strain. Nevertheless, the basic techniques we describe are also applicable to models adapted to investigate other aspects of pathogenesis, such as spatiotemporal patterns of gene expression, specific aspects of host immune response and assessment of antifungal agents, immunomodulatory strategies, and vaccines.

  7. SUSY GUT Model Building

    SciTech Connect

    Raby, Stuart

    2008-11-23

    In this talk I discuss the evolution of SUSY GUT model building as I see it. Starting with 4 dimensional model building, I then consider orbifold GUTs in 5 dimensions and finally orbifold GUTs embedded into the E{sub 8}xE{sub 8} heterotic string.

  8. Modelling University Governance

    ERIC Educational Resources Information Center

    Trakman, Leon

    2008-01-01

    Twentieth century governance models used in public universities are subject to increasing doubt across the English-speaking world. Governments question if public universities are being efficiently governed; if their boards of trustees are adequately fulfilling their trust obligations towards multiple stakeholders; and if collegial models of…

  9. On Some Electroconvection Models

    NASA Astrophysics Data System (ADS)

    Constantin, Peter; Elgindi, Tarek; Ignatova, Mihaela; Vicol, Vlad

    2016-08-01

    We consider a model of electroconvection motivated by studies of the motion of a two-dimensional annular suspended smectic film under the influence of an electric potential maintained at the boundary by two electrodes. We prove that this electroconvection model has global in time unique smooth solutions.

  10. Acid rain: Microphysical model

    NASA Technical Reports Server (NTRS)

    Dingle, A. N.

    1980-01-01

    A microphysical model was used to simulate the case of a ground cloud without dilution by entrainment and without precipitation. The numerical integration techniques of the model are presented. The droplet size spectra versus time and the droplet molalities for each value of time are discussed.

  11. THE AQUATOX MODEL

    EPA Science Inventory

    This lecture will present AQUATOX, an aquatic ecosystem simulation model developed by Dr. Dick Park and supported by the U.S. EPA. The AQUATOX model predicts the fate of various pollutants, such as nutrients and organic chemicals, and their effects on the ecosystem, including fi...

  12. Stormwater Management Model

    EPA Science Inventory

    SWMM is a model for urban hydrology. It has a long history and is relied upon by professional engineers in the US and around the world. SWMM provides both gray and green Infrastructure modeling capabilities. As such, it is a convenient tool for understanding the tradeoff between ...

  13. Structural Equation Model Trees

    ERIC Educational Resources Information Center

    Brandmaier, Andreas M.; von Oertzen, Timo; McArdle, John J.; Lindenberger, Ulman

    2013-01-01

    In the behavioral and social sciences, structural equation models (SEMs) have become widely accepted as a modeling tool for the relation between latent and observed variables. SEMs can be seen as a unification of several multivariate analysis techniques. SEM Trees combine the strengths of SEMs and the decision tree paradigm by building tree…

  14. Generalized simplicial chiral models

    NASA Astrophysics Data System (ADS)

    Alimohammadi, Masoud

    2000-02-01

    Using the auxiliary field representation of the simplicial chiral models on a ( d-1)-dimensional simplex, the simplicial chiral models are generalized through replacing the term Tr (AA †) in the Lagrangian of these models by an arbitrary class function of AA †; V(AA †) . This is the same method used in defining the generalized two-dimensional Yang-Mills theories (gYM 2) from ordinary YM 2. We call these models the "generalized simplicial chiral models". Using the results of the one-link integral over a U( N) matrix, the large- N saddle-point equations for eigenvalue density function ρ( z) in the weak ( β> βc) and strong ( β< βc) regions are computed. In d=2, where the model is in some sense related to the gYM 2 theory, the saddle-point equations are solved for ρ( z) in the two regions, and the explicit value of critical point βc is calculated for V(B)= Tr B n(B=AA †) . For V(B)= Tr B 2, Tr B 3, and Tr B4, the critical behaviour of the model at d=2 is studied, and by calculating the internal energy, it is shown that these models have a third order phase transition.

  15. Introduction to Theoretical Modelling

    NASA Astrophysics Data System (ADS)

    Davis, Matthew J.; Gardiner, Simon A.; Hanna, Thomas M.; Nygaard, Nicolai; Proukakis, Nick P.; Szymańska, Marzena H.

    2013-02-01

    We briefly overview commonly encountered theoretical notions arising in the modelling of quantum gases, intended to provide a unified background to the `language' and diverse theoretical models presented elsewhere in this book, and aimed particularly at researchers from outside the quantum gases community.

  16. Model Children's Code.

    ERIC Educational Resources Information Center

    New Mexico Univ., Albuquerque. American Indian Law Center.

    The Model Children's Code was developed to provide a legally correct model code that American Indian tribes can use to enact children's codes that fulfill their legal, cultural and economic needs. Code sections cover the court system, jurisdiction, juvenile offender procedures, minor-in-need-of-care, and termination. Almost every Code section is…

  17. Reliability model generator specification

    NASA Technical Reports Server (NTRS)

    Cohen, Gerald C.; Mccann, Catherine

    1990-01-01

    The Reliability Model Generator (RMG), a program which produces reliability models from block diagrams for ASSIST, the interface for the reliability evaluation tool SURE is described. An account is given of motivation for RMG and the implemented algorithms are discussed. The appendices contain the algorithms and two detailed traces of examples.

  18. Warm Inflation Model Building

    NASA Astrophysics Data System (ADS)

    Bastero-Gil, Mar; Berera, Arjun

    We review the main aspects of the warm inflation scenario, focusing on the inflationary dynamics and the predictions related to the primordial spectrum of perturbations, to be compared with the recent cosmological observations. We study in detail three different classes of inflationary models, chaotic, hybrid models and hilltop models, and discuss their embedding into supersymmetric models and the consequences for model building of the warm inflationary dynamics based on first principles calculations. Due to the extra friction term introduced in the inflaton background evolution generated by the dissipative dynamics, inflation can take place generically for smaller values of the field, and larger values of couplings and masses. When the dissipative dynamics dominates over the expansion, in the so-called strong dissipative regime, inflation proceeds with sub-Planckian inflaton values. Models can be naturally embedded into a supergravity framework, with SUGRA corrections suppressed by the Planck mass now under control, for a larger class of Kähler potentials. In particular, this provides a simpler solution to the "eta" problem in supersymmetric hybrid inflation, without restricting the Kähler potentials compatible with inflation. For chaotic models dissipation leads to a smaller prediction for the tensor-to-scalar ratio and a less tilted spectrum when compared to the cold inflation scenario. We find in particular that a small component of dissipation renders the quartic model now consistent with the current CMB data.

  19. Computational Modeling of Tires

    NASA Technical Reports Server (NTRS)

    Noor, Ahmed K. (Compiler); Tanner, John A. (Compiler)

    1995-01-01

    This document contains presentations and discussions from the joint UVA/NASA Workshop on Computational Modeling of Tires. The workshop attendees represented NASA, the Army and Air force, tire companies, commercial software developers, and academia. The workshop objectives were to assess the state of technology in the computational modeling of tires and to provide guidelines for future research.

  20. Animal models of tinnitus.

    PubMed

    Brozoski, Thomas J; Bauer, Carol A

    2016-08-01

    Presented is a thematic review of animal tinnitus models from a functional perspective. Chronic tinnitus is a persistent subjective sound sensation, emergent typically after hearing loss. Although the sensation is experientially simple, it appears to have central a nervous system substrate of unexpected complexity that includes areas outside of those classically defined as auditory. Over the past 27 years animal models have significantly contributed to understanding tinnitus' complex neurophysiology. In that time, a diversity of models have been developed, each with its own strengths and limitations. None has clearly become a standard. Animal models trace their origin to the 1988 experiments of Jastreboff and colleagues. All subsequent models derive some of their features from those experiments. Common features include behavior-dependent psychophysical determination, acoustic conditions that contrast objective sound and silence, and inclusion of at least one normal-hearing control group. In the present review, animal models have been categorized as either interrogative or reflexive. Interrogative models use emitted behavior under voluntary control to indicate hearing. An example would be pressing a lever to obtain food in the presence of a particular sound. In this type of model animals are interrogated about their auditory sensations, analogous to asking a patient, "What do you hear?" These models require at least some training and motivation management, and reflect the perception of tinnitus. Reflexive models, in contrast, employ acoustic modulation of an auditory reflex, such as the acoustic startle response. An unexpected loud sound will elicit a reflexive motor response from many species, including humans. Although involuntary, acoustic startle can be modified by a lower-level preceding event, including a silent sound gap. Sound-gap modulation of acoustic startle appears to discriminate tinnitus in animals as well as humans, and requires no training or

  1. Modeling cytomegalovirus infection in mouse tumor models.

    PubMed

    Price, Richard Lee; Chiocca, Ennio Antonio

    2015-01-01

    The hypothesis that cytomegalovirus (CMV) modulates cancer is evolving. Originally discovered in glioblastoma in 2002, the number of cancers, where intratumoral CMV antigen is detected, has increased in recent years suggesting that CMV actively affects the pathobiology of certain tumors. These findings are controversial as several groups have also reported inability to replicate these results. Regardless, several clinical trials for glioblastoma are underway or have been completed that target intratumoral CMV with anti-viral drugs or immunotherapy. Therefore, a better understanding of the possible pathobiology of CMV in cancer needs to be ascertained. We have developed genetic, syngeneic, and orthotopic malignant glioma mouse models to study the role of CMV in cancer development and progression. These models recapitulate for the most part intratumoral CMV expression as seen in human tumors. Additionally, we discovered that CMV infection in Trp53(-/+) mice promotes pleomorphic rhabdomyosarcomas. These mouse models are not only a vehicle for studying pathobiology of the viral-tumor interaction but also a platform for developing and testing cancer therapeutics. PMID:25853089

  2. Integrated Environmental Control Model

    1999-09-03

    IECM is a powerful multimedia engineering software program for simulating an integrated coal-fired power plant. It provides a capability to model various conventional and advanced processes for controlling air pollutant emissions from coal-fired power plants before, during, or after combustion. The principal purpose of the model is to calculate the performance, emissions, and cost of power plant configurations employing alternative environmental control methods. The model consists of various control technology modules, which may be integratedmore » into a complete utility plant in any desired combination. In contrast to conventional deterministic models, the IECM offers the unique capability to assign probabilistic values to all model input parameters, and to obtain probabilistic outputs in the form of cumulative distribution functions indicating the likelihood of dofferent costs and performance results. A Graphical Use Interface (GUI) facilitates the configuration of the technologies, entry of data, and retrieval of results.« less

  3. Modeling earthquake dynamics

    NASA Astrophysics Data System (ADS)

    Charpentier, Arthur; Durand, Marilou

    2015-07-01

    In this paper, we investigate questions arising in Parsons and Geist (Bull Seismol Soc Am 102:1-11, 2012). Pseudo causal models connecting magnitudes and waiting times are considered, through generalized regression. We do use conditional model (magnitude given previous waiting time, and conversely) as an extension to joint distribution model described in Nikoloulopoulos and Karlis (Environmetrics 19: 251-269, 2008). On the one hand, we fit a Pareto distribution for earthquake magnitudes, where the tail index is a function of waiting time following previous earthquake; on the other hand, waiting times are modeled using a Gamma or a Weibull distribution, where parameters are functions of the magnitude of the previous earthquake. We use those two models, alternatively, to generate the dynamics of earthquake occurrence, and to estimate the probability of occurrence of several earthquakes within a year or a decade.

  4. Direct insolation models

    SciTech Connect

    Bird, R.; Hulstrom, R.L.

    1980-01-01

    Several recently published models of the direct component of the broadband insolation are compared for clear sky conditions. The comparison includes seven simple models and one rigorous model that is used as a basis for determining accuracy. Where possible, the comparison is made between the results of each model for each atmospheric constituent (H/sub 2/O, CO/sub 2/, O/sub 3/, O/sub 2/, aerosol and molecular scattering) separately as well as for the combined effect of all of the constituents. Two optimum simple models of varying degrees of complexity are developed as a result of this comparison. The study indicates: aerosols dominate the attenuation of the direct beam for reasonable atmospheric conditions; molecular scattering is next in importance; water vapor is an important absorber; and carbon dioxide and oxygen are relatively unimportant as attenuators of the broadband solar energy.

  5. A Preliminary Jupiter Model

    NASA Astrophysics Data System (ADS)

    Hubbard, W. B.; Militzer, B.

    2016-03-01

    In anticipation of new observational results for Jupiter's axial moment of inertia and gravitational zonal harmonic coefficients from the forthcoming Juno orbiter, we present a number of preliminary Jupiter interior models. We combine results from ab initio computer simulations of hydrogen-helium mixtures, including immiscibility calculations, with a new nonperturbative calculation of Jupiter's zonal harmonic coefficients, to derive a self-consistent model for the planet's external gravity and moment of inertia. We assume helium rain modified the interior temperature and composition profiles. Our calculation predicts zonal harmonic values to which measurements can be compared. Although some models fit the observed (pre-Juno) second- and fourth-order zonal harmonics to within their error bars, our preferred reference model predicts a fourth-order zonal harmonic whose absolute value lies above the pre-Juno error bars. This model has a dense core of about 12 Earth masses and a hydrogen-helium-rich envelope with approximately three times solar metallicity.

  6. Criticality Model Report

    SciTech Connect

    J.M. Scaglione

    2003-03-12

    The purpose of the ''Criticality Model Report'' is to validate the MCNP (CRWMS M&O 1998h) code's ability to accurately predict the effective neutron multiplication factor (k{sub eff}) for a range of conditions spanned by various critical configurations representative of the potential configurations commercial reactor assemblies stored in a waste package may take. Results of this work are an indication of the accuracy of MCNP for calculating eigenvalues, which will be used as input for criticality analyses for spent nuclear fuel (SNF) storage at the proposed Monitored Geologic Repository. The scope of this report is to document the development and validation of the criticality model. The scope of the criticality model is only applicable to commercial pressurized water reactor fuel. Valid ranges are established as part of the validation of the criticality model. This model activity follows the description in BSC (2002a).

  7. Hypertabastic survival model.

    PubMed

    Tabatabai, Mohammad A; Bursac, Zoran; Williams, David K; Singh, Karan P

    2007-10-26

    A new two-parameter probability distribution called hypertabastic is introduced to model the survival or time-to-event data. A simulation study was carried out to evaluate the performance of the hypertabastic distribution in comparison with popular distributions. We then demonstrate the application of the hypertabastic survival model by applying it to data from two motivating studies. The first one demonstrates the proportional hazards version of the model by applying it to a data set from multiple myeloma study. The second one demonstrates an accelerated failure time version of the model by applying it to data from a randomized study of glioma patients who underwent radiotherapy treatment with and without radiosensitizer misonidazole. Based on the results from the simulation study and two applications, the proposed model shows to be a flexible and promising alternative to practitioners in this field.

  8. Testing bow shock models

    NASA Astrophysics Data System (ADS)

    Alrefay, Thamer; Meziane, Karim; Hamza, A. M.

    2016-07-01

    Space plasmas studies of bow shock dynamics, given the fundamental transport role and impact natural transition boundaries, have continued to attract much interest. With the overwhelming availability of data collected by various space science missions, several empirical models have been put forward to account for the location of the Earth's bow shock. Various solar wind and IMF measured parameters are used to constrain the proposed models published in the literature. For each of these empirical models, the bow shock nose velocity, at the standoff distance, is computed; each of these velocities is then compared with the observed shock speed as determined from a multipoint measurement provided by the Cluster quartet. The present study reveals to what extent the model parameters used are significant and determinant, and suggests that some empirical models are more accurate than others are.

  9. Fuzzy object modeling

    NASA Astrophysics Data System (ADS)

    Udupa, Jayaram K.; Odhner, Dewey; Falcao, Alexandre X.; Ciesielski, Krzysztof C.; Miranda, Paulo A. V.; Vaideeswaran, Pavithra; Mishra, Shipra; Grevera, George J.; Saboury, Babak; Torigian, Drew A.

    2011-03-01

    To make Quantitative Radiology (QR) a reality in routine clinical practice, computerized automatic anatomy recognition (AAR) becomes essential. As part of this larger goal, we present in this paper a novel fuzzy strategy for building bodywide group-wise anatomic models. They have the potential to handle uncertainties and variability in anatomy naturally and to be integrated with the fuzzy connectedness framework for image segmentation. Our approach is to build a family of models, called the Virtual Quantitative Human, representing normal adult subjects at a chosen resolution of the population variables (gender, age). Models are represented hierarchically, the descendents representing organs contained in parent organs. Based on an index of fuzziness of the models, 32 thorax data sets, and 10 organs defined in them, we found that the hierarchical approach to modeling can effectively handle the non-linear relationships in position, scale, and orientation that exist among organs in different patients.

  10. Cardiovascular modeling and diagnostics

    SciTech Connect

    Kangas, L.J.; Keller, P.E.; Hashem, S.; Kouzes, R.T.

    1995-12-31

    In this paper, a novel approach to modeling and diagnosing the cardiovascular system is introduced. A model exhibits a subset of the dynamics of the cardiovascular behavior of an individual by using a recurrent artificial neural network. Potentially, a model will be incorporated into a cardiovascular diagnostic system. This approach is unique in that each cardiovascular model is developed from physiological measurements of an individual. Any differences between the modeled variables and the variables of an individual at a given time are used for diagnosis. This approach also exploits sensor fusion to optimize the utilization of biomedical sensors. The advantage of sensor fusion has been demonstrated in applications including control and diagnostics of mechanical and chemical processes.

  11. Rainfall erosion model

    NASA Astrophysics Data System (ADS)

    Sukhanovskii, Yu. P.

    2010-09-01

    A model describing rainfall erosion over the course of a long time period is proposed. The model includes: (1) a new equation of detachment of soil particles by water flows based on the Mirtskhulava equation; (2) a new equation for the transport capacity of the flow based on a modified Bagnold equation, which is used in the AGNPS model; (3) modified SCS runoff equation; (4) probability distributions for rainfall. The proposed equations agree satisfactorily with the data of on-site observations of the Moldova and Nizhnedevitsk water-balance stations. The Monte Carlo method is used for numerical modeling of random variables. The results of modeling agree satisfactorily with empirical equations developed for conditions in Russia and the United States. The effect of climatic conditions on the dependence of longtime average annual soil loss on various factors is analyzed. Minimum information is used for assigning the initial data.

  12. XAFS Model Compound Library

    DOE Data Explorer

    Newville, Matthew

    The XAFS Model Compound Library contains XAFS data on model compounds. The term "model" compounds refers to compounds of homogeneous and well-known crystallographic or molecular structure. Each data file in this library has an associated atoms.inp file that can be converted to a feff.inp file using the program ATOMS. (See the related Searchable Atoms.inp Archive at http://cars9.uchicago.edu/~newville/adb/) This Library exists because XAFS data on model compounds is useful for several reasons, including comparing to unknown data for "fingerprinting" and testing calculations and analysis methods. The collection here is currently limited, but is growing. The focus to date has been on inorganic compounds and minerals of interest to the geochemical community. [Copied, with editing, from http://cars9.uchicago.edu/~newville/ModelLib/

  13. Stochastic patch exploitation model

    PubMed Central

    Rita, H.; Ranta, E.

    1998-01-01

    A solitary animal is foraging in a patch consisting of discrete prey items. We develop a stochastic model for the accumulation of gain as a function of elapsed time in the patch. The model is based on the waiting times between subsequent encounters with the prey items. The novelty of the model is in that it renders possible–via parameterization of the waiting time distributions: the incorporation of different foraging situations and patch structures into the gain process. The flexibility of the model is demonstrated with different foraging scenarios. Dependence of gain expectation and variance of the parameters of the waiting times is studied under these conditions. The model allows us to comment upon some of the basic concepts in contemporary foraging theory.

  14. Impedance modelling of pipes

    NASA Astrophysics Data System (ADS)

    Creasy, M. Austin

    2016-03-01

    Impedance models of pipes can be used to estimate resonant frequencies of standing waves and model acoustic pressure of closed and open ended pipes. Modelling a pipe with impedance methods allows additional variations to the pipe to be included in the overall model as a system. Therefore an actuator can be attached and used to drive the system and the impedance model is able to include the dynamics of the actuator. Exciting the pipe system with a chirp signal allows resonant frequencies to be measured in both the time and frequency domain. The measurements in the time domain are beneficial for introducing undergraduates to resonances without needing an understanding of fast Fourier transforms. This paper also discusses resonant frequencies in open ended pipes and how numerous texts incorrectly approximate the resonant frequencies for this specific pipe system.

  15. Proton channel models

    PubMed Central

    Pupo, Amaury; Baez-Nieto, David; Martínez, Agustín; Latorre, Ramón; González, Carlos

    2014-01-01

    Voltage-gated proton channels are integral membrane proteins with the capacity to permeate elementary particles in a voltage and pH dependent manner. These proteins have been found in several species and are involved in various physiological processes. Although their primary topology is known, lack of details regarding their structures in the open conformation has limited analyses toward a deeper understanding of the molecular determinants of their function and regulation. Consequently, the function-structure relationships have been inferred based on homology models. In the present work, we review the existing proton channel models, their assumptions, predictions and the experimental facts that support them. Modeling proton channels is not a trivial task due to the lack of a close homolog template. Hence, there are important differences between published models. This work attempts to critically review existing proton channel models toward the aim of contributing to a better understanding of the structural features of these proteins. PMID:24755912

  16. Stratiform chromite deposit model

    USGS Publications Warehouse

    Schulte, Ruth F.; Taylor, Ryan D.; Piatak, Nadine M.; Seal, Robert R., II

    2010-01-01

    Stratiform chromite deposits are of great economic importance, yet their origin and evolution remain highly debated. Layered igneous intrusions such as the Bushveld, Great Dyke, Kemi, and Stillwater Complexes, provide opportunities for studying magmatic differentiation processes and assimilation within the crust, as well as related ore-deposit formation. Chromite-rich seams within layered intrusions host the majority of the world's chromium reserves and may contain significant platinum-group-element (PGE) mineralization. This model of stratiform chromite deposits is part of an effort by the U.S. Geological Survey's Mineral Resources Program to update existing models and develop new descriptive mineral deposit models to supplement previously published models for use in mineral-resource and mineral-environmental assessments. The model focuses on features that may be common to all stratiform chromite deposits as a way to gain insight into the processes that gave rise to their emplacement and to the significant economic resources contained in them.

  17. Updating applied diffusion models

    SciTech Connect

    Weil, J.C.

    1985-01-01

    Most diffusion models currently used in air-quality applications are substantially out of date with understanding of turbulence and diffusion in the planetary boundary layer. Under a Cooperative Agreement with the Environmental Protection Agency, the American Meteorological Society organized a workshop to help improve the basis of such models, their physics and hopefully their performance. Reviews and recommendations were made on models in three areas: diffusion in the convective boundary layer (CBL), diffusion in the stable boundary layer (SBL), and model uncertainty. Progress has been made in all areas, but it is most significant and ready for application to practical models in the case of the CBL. This has resulted from a clear understanding of the vertical structure and diffusion in the CBL, as demonstrated by laboratory experiments, numerical simulations, and field observations. Understanding of turbulence structure and diffusion in the SBL is less complete and not yet ready for general use in applications.

  18. Strength Modeling Report

    NASA Technical Reports Server (NTRS)

    Badler, N. I.; Lee, P.; Wong, S.

    1985-01-01

    Strength modeling is a complex and multi-dimensional issue. There are numerous parameters to the problem of characterizing human strength, most notably: (1) position and orientation of body joints; (2) isometric versus dynamic strength; (3) effector force versus joint torque; (4) instantaneous versus steady force; (5) active force versus reactive force; (6) presence or absence of gravity; (7) body somatotype and composition; (8) body (segment) masses; (9) muscle group envolvement; (10) muscle size; (11) fatigue; and (12) practice (training) or familiarity. In surveying the available literature on strength measurement and modeling an attempt was made to examine as many of these parameters as possible. The conclusions reached at this point toward the feasibility of implementing computationally reasonable human strength models. The assessment of accuracy of any model against a specific individual, however, will probably not be possible on any realistic scale. Taken statistically, strength modeling may be an effective tool for general questions of task feasibility and strength requirements.

  19. Varicella infection modeling.

    SciTech Connect

    Jones, Katherine A.; Finley, Patrick D.; Moore, Thomas W.; Nozick, Linda Karen; Martin, Nathaniel; Bandlow, Alisa; Detry, Richard Joseph; Evans, Leland B.; Berger, Taylor Eugen

    2013-09-01

    Infectious diseases can spread rapidly through healthcare facilities, resulting in widespread illness among vulnerable patients. Computational models of disease spread are useful for evaluating mitigation strategies under different scenarios. This report describes two infectious disease models built for the US Department of Veteran Affairs (VA) motivated by a Varicella outbreak in a VA facility. The first model simulates disease spread within a notional contact network representing staff and patients. Several interventions, along with initial infection counts and intervention delay, were evaluated for effectiveness at preventing disease spread. The second model adds staff categories, location, scheduling, and variable contact rates to improve resolution. This model achieved more accurate infection counts and enabled a more rigorous evaluation of comparative effectiveness of interventions.

  20. VENTILATION MODEL REPORT

    SciTech Connect

    V. Chipman

    2002-10-31

    The purpose of the Ventilation Model is to simulate the heat transfer processes in and around waste emplacement drifts during periods of forced ventilation. The model evaluates the effects of emplacement drift ventilation on the thermal conditions in the emplacement drifts and surrounding rock mass, and calculates the heat removal by ventilation as a measure of the viability of ventilation to delay the onset of peak repository temperature and reduce its magnitude. The heat removal by ventilation is temporally and spatially dependent, and is expressed as the fraction of heat carried away by the ventilation air compared to the fraction of heat produced by radionuclide decay. One minus the heat removal is called the wall heat fraction, or the remaining amount of heat that is transferred via conduction to the surrounding rock mass. Downstream models, such as the ''Multiscale Thermohydrologic Model'' (BSC 2001), use the wall heat fractions as outputted from the Ventilation Model to initialize their postclosure analyses.

  1. Conditional statistical model building

    NASA Astrophysics Data System (ADS)

    Hansen, Mads Fogtmann; Hansen, Michael Sass; Larsen, Rasmus

    2008-03-01

    We present a new statistical deformation model suited for parameterized grids with different resolutions. Our method models the covariances between multiple grid levels explicitly, and allows for very efficient fitting of the model to data on multiple scales. The model is validated on a data set consisting of 62 annotated MR images of Corpus Callosum. One fifth of the data set was used as a training set, which was non-rigidly registered to each other without a shape prior. From the non-rigidly registered training set a shape prior was constructed by performing principal component analysis on each grid level and using the results to construct a conditional shape model, conditioning the finer parameters with the coarser grid levels. The remaining shapes were registered with the constructed shape prior. The dice measures for the registration without prior and the registration with a prior were 0.875 +/- 0.042 and 0.8615 +/- 0.051, respectively.

  2. Modeling glacial climates

    NASA Technical Reports Server (NTRS)

    North, G. R.; Crowley, T. J.

    1984-01-01

    Mathematical climate modelling has matured as a discipline to the point that it is useful in paleoclimatology. As an example a new two dimensional energy balance model is described and applied to several problems of current interest. The model includes the seasonal cycle and the detailed land-sea geographical distribution. By examining the changes in the seasonal cycle when external perturbations are forced upon the climate system it is possible to construct hypotheses about the origin of midlatitude ice sheets and polar ice caps. In particular the model predicts a rather sudden potential for glaciation over large areas when the Earth's orbital elements are only slightly altered. Similarly, the drift of continents or the change of atmospheric carbon dioxide over geological time induces radical changes in continental ice cover. With the advance of computer technology and improved understanding of the individual components of the climate system, these ideas will be tested in far more realistic models in the near future.

  3. Global ice sheet modeling

    SciTech Connect

    Hughes, T.J.; Fastook, J.L.

    1994-05-01

    The University of Maine conducted this study for Pacific Northwest Laboratory (PNL) as part of a global climate modeling task for site characterization of the potential nuclear waste respository site at Yucca Mountain, NV. The purpose of the study was to develop a global ice sheet dynamics model that will forecast the three-dimensional configuration of global ice sheets for specific climate change scenarios. The objective of the third (final) year of the work was to produce ice sheet data for glaciation scenarios covering the next 100,000 years. This was accomplished using both the map-plane and flowband solutions of our time-dependent, finite-element gridpoint model. The theory and equations used to develop the ice sheet models are presented. Three future scenarios were simulated by the model and results are discussed.

  4. Integrated Workforce Modeling System

    NASA Technical Reports Server (NTRS)

    Moynihan, Gary P.

    2000-01-01

    There are several computer-based systems, currently in various phases of development at KSC, which encompass some component, aspect, or function of workforce modeling. These systems may offer redundant capabilities and/or incompatible interfaces. A systems approach to workforce modeling is necessary in order to identify and better address user requirements. This research has consisted of two primary tasks. Task 1 provided an assessment of existing and proposed KSC workforce modeling systems for their functionality and applicability to the workforce planning function. Task 2 resulted in the development of a proof-of-concept design for a systems approach to workforce modeling. The model incorporates critical aspects of workforce planning, including hires, attrition, and employee development.

  5. Linear models: permutation methods

    USGS Publications Warehouse

    Cade, B.S.; Everitt, B.S.; Howell, D.C.

    2005-01-01

    Permutation tests (see Permutation Based Inference) for the linear model have applications in behavioral studies when traditional parametric assumptions about the error term in a linear model are not tenable. Improved validity of Type I error rates can be achieved with properly constructed permutation tests. Perhaps more importantly, increased statistical power, improved robustness to effects of outliers, and detection of alternative distributional differences can be achieved by coupling permutation inference with alternative linear model estimators. For example, it is well-known that estimates of the mean in linear model are extremely sensitive to even a single outlying value of the dependent variable compared to estimates of the median [7, 19]. Traditionally, linear modeling focused on estimating changes in the center of distributions (means or medians). However, quantile regression allows distributional changes to be estimated in all or any selected part of a distribution or responses, providing a more complete statistical picture that has relevance to many biological questions [6]...

  6. Beyond the Standard Model

    SciTech Connect

    Peskin, M.E.

    1997-05-01

    These lectures constitute a short course in ``Beyond the Standard Model`` for students of experimental particle physics. The author discusses the general ideas which guide the construction of models of physics beyond the Standard model. The central principle, the one which most directly motivates the search for new physics, is the search for the mechanism of the spontaneous symmetry breaking observed in the theory of weak interactions. To illustrate models of weak-interaction symmetry breaking, the author gives a detailed discussion of the idea of supersymmetry and that of new strong interactions at the TeV energy scale. He discusses experiments that will probe the details of these models at future pp and e{sup +}e{sup {minus}} colliders.

  7. Open ocean tide modelling

    NASA Technical Reports Server (NTRS)

    Parke, M. E.

    1978-01-01

    Two trends evident in global tidal modelling since the first GEOP conference in 1972 are described. The first centers on the incorporation of terms for ocean loading and gravitational self attraction into Laplace's tidal equations. The second centers on a better understanding of the problem of near resonant modelling and the need for realistic maps of tidal elevation for use by geodesists and geophysicists. Although new models still show significant differences, especially in the South Atlantic, there are significant similarities in many of the world's oceans. This allows suggestions to be made for future locations for bottom pressure gauge measurements. Where available, estimates of M2 tidal dissipation from the new models are significantly lower than estimates from previous models.

  8. Australia's Next Top Fraction Model

    ERIC Educational Resources Information Center

    Gould, Peter

    2013-01-01

    Peter Gould suggests Australia's next top fraction model should be a linear model rather than an area model. He provides a convincing argument and gives examples of ways to introduce a linear model in primary classrooms.

  9. Staged Models for Interdisciplinary Research.

    PubMed

    Lafuerza, Luis F; Dyson, Louise; Edmonds, Bruce; McKane, Alan J

    2016-01-01

    Modellers of complex biological or social systems are often faced with an invidious choice: to use simple models with few mechanisms that can be fully analysed, or to construct complicated models that include all the features which are thought relevant. The former ensures rigour, the latter relevance. We discuss a method that combines these two approaches, beginning with a complex model and then modelling the complicated model with simpler models. The resulting "chain" of models ensures some rigour and relevance. We illustrate this process on a complex model of voting intentions, constructing a reduced model which agrees well with the predictions of the full model. Experiments with variations of the simpler model yield additional insights which are hidden by the complexity of the full model. This approach facilitated collaboration between social scientists and physicists-the complex model was specified based on the social science literature, and the simpler model constrained to agree (in core aspects) with the complicated model. PMID:27362836

  10. Saturn Radiation (SATRAD) Model

    NASA Technical Reports Server (NTRS)

    Garrett, H. B.; Ratliff, J. M.; Evans, R. W.

    2005-01-01

    The Saturnian radiation belts have not received as much attention as the Jovian radiation belts because they are not nearly as intense-the famous Saturnian particle rings tend to deplete the belts near where their peak would occur. As a result, there has not been a systematic development of engineering models of the Saturnian radiation environment for mission design. A primary exception is that of Divine (1990). That study used published data from several charged particle experiments aboard the Pioneer 1 1, Voyager 1, and Voyager 2 spacecraft during their flybys at Saturn to generate numerical models for the electron and proton radiation belts between 2.3 and 13 Saturn radii. The Divine Saturn radiation model described the electron distributions at energies between 0.04 and 10 MeV and the proton distributions at energies between 0.14 and 80 MeV. The model was intended to predict particle intensity, flux, and fluence for the Cassini orbiter. Divine carried out hand calculations using the model but never formally developed a computer program that could be used for general mission analyses. This report seeks to fill that void by formally developing a FORTRAN version of the model that can be used as a computer design tool for missions to Saturn that require estimates of the radiation environment around the planet. The results of that effort and the program listings are presented here along with comparisons with the original estimates carried out by Divine. In addition, Pioneer and Voyager data were scanned in from the original references and compared with the FORTRAN model s predictions. The results were statistically analyzed in a manner consistent with Divine s approach to provide estimates of the ability of the model to reproduce the original data. Results of a formal review of the model by a panel of experts are also presented. Their recommendations for further tests, analyses, and extensions to the model are discussed.

  11. Maximally Expressive Task Modeling

    NASA Technical Reports Server (NTRS)

    Japp, John; Davis, Elizabeth; Maxwell, Theresa G. (Technical Monitor)

    2002-01-01

    Planning and scheduling systems organize "tasks" into a timeline or schedule. The tasks are defined within the scheduling system in logical containers called models. The dictionary might define a model of this type as "a system of things and relations satisfying a set of rules that, when applied to the things and relations, produce certainty about the tasks that are being modeled." One challenging domain for a planning and scheduling system is the operation of on-board experiment activities for the Space Station. The equipment used in these experiments is some of the most complex hardware ever developed by mankind, the information sought by these experiments is at the cutting edge of scientific endeavor, and the procedures for executing the experiments are intricate and exacting. Scheduling is made more difficult by a scarcity of space station resources. The models to be fed into the scheduler must describe both the complexity of the experiments and procedures (to ensure a valid schedule) and the flexibilities of the procedures and the equipment (to effectively utilize available resources). Clearly, scheduling space station experiment operations calls for a "maximally expressive" modeling schema. Modeling even the simplest of activities cannot be automated; no sensor can be attached to a piece of equipment that can discern how to use that piece of equipment; no camera can quantify how to operate a piece of equipment. Modeling is a human enterprise-both an art and a science. The modeling schema should allow the models to flow from the keyboard of the user as easily as works of literature flowed from the pen of Shakespeare. The Ground Systems Department at the Marshall Space Flight Center has embarked on an effort to develop a new scheduling engine that is highlighted by a maximally expressive modeling schema. This schema, presented in this paper, is a synergy of technological advances and domain-specific innovations.

  12. Animal Models of Atherosclerosis

    PubMed Central

    Getz, Godfrey S.; Reardon, Catherine A.

    2012-01-01

    Atherosclerosis is a chronic inflammatory disorder that is the underlying cause of most cardiovascular disease. Both cells of the vessel wall and cells of the immune system participate in atherogenesis. This process is heavily influenced by plasma lipoproteins, genetics and the hemodynamics of the blood flow in the artery. A variety of small and large animal models have been used to study the atherogenic process. No model is ideal as each has its own advantages and limitations with respect to manipulation of the atherogenic process and modeling human atherosclerosis or lipoprotein profile. Useful large animal models include pigs, rabbits and non-human primates. Due in large part to the relative ease of genetic manipulation and the relatively short time frame for the development of atherosclerosis, murine models are currently the most extensively used. While not all aspects of murine atherosclerosis are identical to humans, studies using murine models have suggested potential biological processes and interactions that underlie this process. As it becomes clear that different factors may influence different stages of lesion development, the use of mouse models with the ability to turn on or delete proteins or cells in tissue specific and temporal manner will be very valuable. PMID:22383700

  13. VPPA weld model evaluation

    NASA Astrophysics Data System (ADS)

    McCutcheon, Kimble D.; Gordon, Stephen S.; Thompson, Paul A.

    1992-07-01

    NASA uses the Variable Polarity Plasma Arc Welding (VPPAW) process extensively for fabrication of Space Shuttle External Tanks. This welding process has been in use at NASA since the late 1970's but the physics of the process have never been satisfactorily modeled and understood. In an attempt to advance the level of understanding of VPPAW, Dr. Arthur C. Nunes, Jr., (NASA) has developed a mathematical model of the process. The work described in this report evaluated and used two versions (level-0 and level-1) of Dr. Nunes' model, and a model derived by the University of Alabama at Huntsville (UAH) from Dr. Nunes' level-1 model. Two series of VPPAW experiments were done, using over 400 different combinations of welding parameters. Observations were made of VPPAW process behavior as a function of specific welding parameter changes. Data from these weld experiments was used to evaluate and suggest improvements to Dr. Nunes' model. Experimental data and correlations with the model were used to develop a multi-variable control algorithm for use with a future VPPAW controller. This algorithm is designed to control weld widths (both on the crown and root of the weld) based upon the weld parameters, base metal properties, and real-time observation of the crown width. The algorithm exhibited accuracy comparable to that of the weld width measurements for both aluminum and mild steel welds.

  14. Biophysical models in hadrontherapy

    NASA Astrophysics Data System (ADS)

    Scholz, M.; Elsaesser, T.

    One major rationale for the application of ion beams in tumor therapy is their increased relative biological effectiveness RBE in the Bragg peak region For dose prescription the increased effectiveness has to be taken into account in treatment planning Hence the complex dependencies of RBE on the dose level biological endpoint position in the field etc require biophysical models which have to fulfill two important criteria simplicity and quantitative precision Simplicity means that the number of free parameters should be kept at a minimum Due to the lack of precise quantitative data at least at present this requirement is incompatible with approaches aiming at the molecular modeling of the whole chain of production processing and repair of biological damages Quantitative precision is required since steep gradients in the dose response curves are observed for most tumor and normal tissues thus even small uncertainties in the estimation of the biologically effective dose can transform into large uncertainties in the clinical outcome The paper will give a general introduction into the field followed by a brief description of a specific model the so called Local Effect Model LEM This model has been successfully applied within treatment planning in the GSI pilot project for carbon ion tumor therapy over almost 10 years now The model is based on the knowledge of charged particle track structure in combination with the response of the biological objects to conventional photon radiation The model will be critically discussed with respect to other

  15. Acute radiation risk models

    NASA Astrophysics Data System (ADS)

    Smirnova, Olga

    Biologically motivated mathematical models, which describe the dynamics of the major hematopoietic lineages (the thrombocytopoietic, lymphocytopoietic, granulocytopoietic, and erythropoietic systems) in acutely/chronically irradiated humans are developed. These models are implemented as systems of nonlinear differential equations, which variables and constant parameters have clear biological meaning. It is shown that the developed models are capable of reproducing clinical data on the dynamics of these systems in humans exposed to acute radiation in the result of incidents and accidents, as well as in humans exposed to low-level chronic radiation. Moreover, the averaged value of the "lethal" dose rates of chronic irradiation evaluated within models of these four major hematopoietic lineages coincides with the real minimal dose rate of lethal chronic irradiation. The demonstrated ability of the models of the human thrombocytopoietic, lymphocytopoietic, granulocytopoietic, and erythropoietic systems to predict the dynamical response of these systems to acute/chronic irradiation in wide ranges of doses and dose rates implies that these mathematical models form an universal tool for the investigation and prediction of the dynamics of the major human hematopoietic lineages for a vast pattern of irradiation scenarios. In particular, these models could be applied for the radiation risk assessment for health of astronauts exposed to space radiation during long-term space missions, such as voyages to Mars or Lunar colonies, as well as for health of people exposed to acute/chronic irradiation due to environmental radiological events.

  16. Modeling mitochondrial function.

    PubMed

    Balaban, Robert S

    2006-12-01

    The mitochondrion represents a unique opportunity to apply mathematical modeling to a complex biological system. Understanding mitochondrial function and control is important since this organelle is critical in energy metabolism as well as playing key roles in biochemical synthesis, redox control/signaling, and apoptosis. A mathematical model, or hypothesis, provides several useful insights including a rigorous test of the consensus view of the operation of a biological process as well as providing methods of testing and creating new hypotheses. The advantages of the mitochondrial system for applying a mathematical model include the relative simplicity and understanding of the matrix reactions, the ability to study the mitochondria as a independent contained organelle, and, most importantly, one can dynamically measure many of the internal reaction intermediates, on line. The developing ability to internally monitor events within the metabolic network, rather than just the inflow and outflow, is extremely useful in creating critical bounds on complex mathematical models using the individual reaction mechanisms available. However, many serious problems remain in creating a working model of mitochondrial function including the incomplete definition of metabolic pathways, the uncertainty of using in vitro enzyme kinetics, as well as regulatory data in the intact system and the unknown chemical activities of relevant molecules in the matrix. Despite these formidable limitations, the advantages of the mitochondrial system make it one of the best defined mammalian metabolic networks that can be used as a model system for understanding the application and use of mathematical models to study biological systems.

  17. Invertebrate models of alcoholism.

    PubMed

    Scholz, Henrike; Mustard, Julie A

    2013-01-01

    For invertebrates to become useful models for understanding the genetic and physiological mechanisms of alcoholism related behaviors and the predisposition towards alcoholism, several general requirements must be fulfilled. The animal should encounter ethanol in its natural habitat, so that the central nervous system of the organism will have evolved mechanisms for responding to ethanol exposure. How the brain adapts to ethanol exposure depends on its access to ethanol, which can be regulated metabolically and/or by physical barriers. Therefore, a model organism should have metabolic enzymes for ethanol degradation similar to those found in humans. The neurons and supporting glial cells of the model organism that regulate behaviors affected by ethanol should share the molecular and physiological pathways found in humans, so that results can be compared. Finally, the use of invertebrate models should offer advantages over traditional model systems and should offer new insights into alcoholism-related behaviors. In this review we will summarize behavioral similarities and identified genes and mechanisms underlying ethanol-induced behaviors in invertebrates. This review mainly focuses on the use of the nematode Caenorhabditis elegans, the honey bee Apis mellifera and the fruit fly Drosophila melanogaster as model systems. We will discuss insights gained from those studies in conjunction with their vertebrate model counterparts and the implications for future research into alcoholism and alcohol-induced behaviors.

  18. Intraocular Lymphoma Models

    PubMed Central

    Aronow, Mary E.; Shen, Defen; Hochman, Jacob; Chan, Chi-Chao

    2015-01-01

    Primary vitreoretinal lymphoma (PVRL) is a subtype of primary central nervous system lymphoma (PCNSL), a high-grade, extranodal, non-Hodgkin's lymphoma, predominantly of B-cell origin. PVRL is an aggressive disease with a poor prognosis. Human studies are not ideally suited for the study of intraocular lymphoma pathogenesis or treatment strategies due to the rare nature of the disease, its variable presentation, limited volume of available ocular fluids, and fragility of sampled lymphoma cells. Animal models have been critical in making progress in understanding intraocular lymphoma pathogenesis and investigating potential therapeutic strategies. Early murine models for intraocular lymphoma used intraperitoneal injection of mouse T-cell lymphomas. This was followed by intravitreal T-cell murine models. More recent murine models have used B-cell lymphomas to more closely mimic human disease. The most current B-cell lymphoma models employ a combined approach of inoculating both the mouse vitreous cavity and brain. The challenge in murine models for intraocular lymphoma lies in recreating the clinical features, disease behavior, molecular profile, systemic immunity, and the microenvironment observed in human disease. In the future, animal models will continue to be central to furthering our understanding of the disease and in the investigation of potential treatment targets. PMID:27171354

  19. VPPA weld model evaluation

    NASA Technical Reports Server (NTRS)

    Mccutcheon, Kimble D.; Gordon, Stephen S.; Thompson, Paul A.

    1992-01-01

    NASA uses the Variable Polarity Plasma Arc Welding (VPPAW) process extensively for fabrication of Space Shuttle External Tanks. This welding process has been in use at NASA since the late 1970's but the physics of the process have never been satisfactorily modeled and understood. In an attempt to advance the level of understanding of VPPAW, Dr. Arthur C. Nunes, Jr., (NASA) has developed a mathematical model of the process. The work described in this report evaluated and used two versions (level-0 and level-1) of Dr. Nunes' model, and a model derived by the University of Alabama at Huntsville (UAH) from Dr. Nunes' level-1 model. Two series of VPPAW experiments were done, using over 400 different combinations of welding parameters. Observations were made of VPPAW process behavior as a function of specific welding parameter changes. Data from these weld experiments was used to evaluate and suggest improvements to Dr. Nunes' model. Experimental data and correlations with the model were used to develop a multi-variable control algorithm for use with a future VPPAW controller. This algorithm is designed to control weld widths (both on the crown and root of the weld) based upon the weld parameters, base metal properties, and real-time observation of the crown width. The algorithm exhibited accuracy comparable to that of the weld width measurements for both aluminum and mild steel welds.

  20. SPAR Model Structural Efficiencies

    SciTech Connect

    John Schroeder; Dan Henry

    2013-04-01

    The Nuclear Regulatory Commission (NRC) and the Electric Power Research Institute (EPRI) are supporting initiatives aimed at improving the quality of probabilistic risk assessments (PRAs). Included in these initiatives are the resolution of key technical issues that are have been judged to have the most significant influence on the baseline core damage frequency of the NRC’s Standardized Plant Analysis Risk (SPAR) models and licensee PRA models. Previous work addressed issues associated with support system initiating event analysis and loss of off-site power/station blackout analysis. The key technical issues were: • Development of a standard methodology and implementation of support system initiating events • Treatment of loss of offsite power • Development of standard approach for emergency core cooling following containment failure Some of the related issues were not fully resolved. This project continues the effort to resolve outstanding issues. The work scope was intended to include substantial collaboration with EPRI; however, EPRI has had other higher priority initiatives to support. Therefore this project has addressed SPAR modeling issues. The issues addressed are • SPAR model transparency • Common cause failure modeling deficiencies and approaches • Ac and dc modeling deficiencies and approaches • Instrumentation and control system modeling deficiencies and approaches

  1. Atmospheric Models for Aerocapture

    NASA Technical Reports Server (NTRS)

    Justus, C. G.; Duvall, Aleta L.; Keller, Vernon W.

    2004-01-01

    There are eight destinations in the solar System with sufficient atmosphere for aerocapture to be a viable aeroassist option - Venus, Earth, Mars, Jupiter, Saturn and its moon Titan, Uranus, and Neptune. Engineering-level atmospheric models for four of these targets (Earth, Mars, Titan, and Neptune) have been developed for NASA to support systems analysis studies of potential future aerocapture missions. Development of a similar atmospheric model for Venus has recently commenced. An important capability of all of these models is their ability to simulate quasi-random density perturbations for Monte Carlo analyses in developing guidance, navigation and control algorithm, and for thermal systems design. Similarities and differences among these atmospheric models are presented, with emphasis on the recently developed Neptune model and on planned characteristics of the Venus model. Example applications for aerocapture are also presented and illustrated. Recent updates to the Titan atmospheric model are discussed, in anticipation of applications for trajectory and atmospheric reconstruct of Huygens Probe entry at Titan.

  2. Functional Generalized Additive Models.

    PubMed

    McLean, Mathew W; Hooker, Giles; Staicu, Ana-Maria; Scheipl, Fabian; Ruppert, David

    2014-01-01

    We introduce the functional generalized additive model (FGAM), a novel regression model for association studies between a scalar response and a functional predictor. We model the link-transformed mean response as the integral with respect to t of F{X(t), t} where F(·,·) is an unknown regression function and X(t) is a functional covariate. Rather than having an additive model in a finite number of principal components as in Müller and Yao (2008), our model incorporates the functional predictor directly and thus our model can be viewed as the natural functional extension of generalized additive models. We estimate F(·,·) using tensor-product B-splines with roughness penalties. A pointwise quantile transformation of the functional predictor is also considered to ensure each tensor-product B-spline has observed data on its support. The methods are evaluated using simulated data and their predictive performance is compared with other competing scalar-on-function regression alternatives. We illustrate the usefulness of our approach through an application to brain tractography, where X(t) is a signal from diffusion tensor imaging at position, t, along a tract in the brain. In one example, the response is disease-status (case or control) and in a second example, it is the score on a cognitive test. R code for performing the simulations and fitting the FGAM can be found in supplemental materials available online.

  3. Computationally modeling interpersonal trust

    PubMed Central

    Lee, Jin Joo; Knox, W. Bradley; Wormwood, Jolie B.; Breazeal, Cynthia; DeSteno, David

    2013-01-01

    We present a computational model capable of predicting—above human accuracy—the degree of trust a person has toward their novel partner by observing the trust-related nonverbal cues expressed in their social interaction. We summarize our prior work, in which we identify nonverbal cues that signal untrustworthy behavior and also demonstrate the human mind's readiness to interpret those cues to assess the trustworthiness of a social robot. We demonstrate that domain knowledge gained from our prior work using human-subjects experiments, when incorporated into the feature engineering process, permits a computational model to outperform both human predictions and a baseline model built in naiveté of this domain knowledge. We then present the construction of hidden Markov models to investigate temporal relationships among the trust-related nonverbal cues. By interpreting the resulting learned structure, we observe that models built to emulate different levels of trust exhibit different sequences of nonverbal cues. From this observation, we derived sequence-based temporal features that further improve the accuracy of our computational model. Our multi-step research process presented in this paper combines the strength of experimental manipulation and machine learning to not only design a computational trust model but also to further our understanding of the dynamics of interpersonal trust. PMID:24363649

  4. Interactive geologic modeling

    SciTech Connect

    Glaeser, J.D.; Krajewski, S.A.

    1984-04-01

    Improved success in finding hydrocarbons and minerals depends on developing geologic models from seismic, gravity, and magnetic data that most closely approximate real-world settings. Although data processing remains the chore of mainframe and minicomputers, interpretations and modeling of geologic and geophysical information now are best accomplished on personal computers because these computers afford the explorationist maximum freedom to shape and fine tune geophysical evaluations. Three case histories use the GEOSIM geophysical modeling systems to delineate exploration targets. The first example is Silurian Niagaran reef trends in the Michigan basin. Here, differences in seismic reef anomalies result from variations in carbonate-evaporite stratigraphy encasing the reefs, reef geometry, and reef reservoir parameters. These variations which influence real seismic-response differences can be successfully matched using appropriate geologic models in generating synthetic seismic reef anomalies. The second example applies gravity and magnetic data to seismic modeling of a Wyoming coal field. Detailed seismic stratigraphy helps locate those portions of the field having multiple seams, although it does not resolve individual economic zones. Gravity data do identify pinchout margins of multiseam zones and pinchouts between principal coals. Magnetic data are then used to delineate the burn (clinker) margin. Seismic modeling of subtle stratigraphic traps is the broader area of exploration interest contained in the first 2 examples. In the third, successfully modeled and tested examples of lateral changes in deltaic facies and of faulted, unconformity-bounded continent-margin sequences are shown to be successful guides to reinterpretation of seismic data.

  5. SSCL groundwater model

    SciTech Connect

    Romero, V.; Bull, J.; Stapleton, G.; Baker, S.; Goss, D.; Coulson, L.

    1994-02-01

    Activation of groundwater due to accelerator operations has been a consideration since the conceptual stages of the SSC. Prior to site selection, an elementary hydrological model assuming a porous medium with a shallow well in proximity to the tunnel was used to determine the radionuclide concentrations in the water pumped from a well. The model assumed that radionuclides produced within a few feet of the tunnel would migrate to the shallow well and be diluted as the well drew water from a conically symmetric region. After the Ellis County site was selected, the compatibility of this model with the site specific geology was evaluated. The host geology at the selected site is low permeability rock, Austin chalk, shale, and marl, however, vertical fractures do exist. Since the host rock has a low permeability, groundwater in proximity to the tunnel would have to travel primarily through fractures. This hydrology is not compatible with the above mentioned model since water does not percolate uniformly from the surrounding rock into local wells. The amount of dilution of activated water will vary significantly depending on the specific relationship of the well to the activation zone. A further complication in the original model is that it assumes the high energy particles escaping from the accelerator enclosure are localized. The model does not provide for particles being lost over a large area as will happen with routine operational losses. These losses will be distributed along the accelerator over the life of the project. The SSCL groundwater model has been recast to account for the site specific hydrology and both point and distributed losses. Using the new groundwater model, the SSC accelerators are designed to limit the activation concentration in the water located one meter outside the accelerator enclosure to meet the federal drinking water standards. This technical note provides the details of this model.

  6. Turbulence Modeling Workshop

    NASA Technical Reports Server (NTRS)

    Rubinstein, R. (Editor); Rumsey, C. L. (Editor); Salas, M. D. (Editor); Thomas, J. L. (Editor); Bushnell, Dennis M. (Technical Monitor)

    2001-01-01

    Advances in turbulence modeling are needed in order to calculate high Reynolds number flows near the onset of separation and beyond. To this end, the participants in this workshop made the following recommendations. (1) A national/international database and standards for turbulence modeling assessment should be established. Existing experimental data sets should be reviewed and categorized. Advantage should be taken of other efforts already under-way, such as that of the European Research Community on Flow, Turbulence, and Combustion (ERCOFTAC) consortium. Carefully selected "unit" experiments will be needed, as well as advances in instrumentation, to fill the gaps in existing datasets. A high priority should be given to document existing turbulence model capabilities in a standard form, including numerical implementation issues such as grid quality and resolution. (2) NASA should support long-term research on Algebraic Stress Models and Reynolds Stress Models. The emphasis should be placed on improving the length-scale equation, since it is the least understood and is a key component of two-equation and higher models. Second priority should be given to the development of improved near-wall models. Direct Numerical Simulations (DNS) and Large Eddy Simulations (LES) would provide valuable guidance in developing and validating new Reynolds-averaged Navier-Stokes (RANS) models. Although not the focus of this workshop, DNS, LES, and hybrid methods currently represent viable approaches for analysis on a limited basis. Therefore, although computer limitations require the use of RANS methods for realistic configurations at high Reynolds number in the foreseeable future, a balanced effort in turbulence modeling development, validation, and implementation should include these approaches as well.

  7. SMC: SCENIC Model Control

    NASA Technical Reports Server (NTRS)

    Srivastava, Priyaka; Kraus, Jeff; Murawski, Robert; Golden, Bertsel, Jr.

    2015-01-01

    NASAs Space Communications and Navigation (SCaN) program manages three active networks: the Near Earth Network, the Space Network, and the Deep Space Network. These networks simultaneously support NASA missions and provide communications services to customers worldwide. To efficiently manage these resources and their capabilities, a team of student interns at the NASA Glenn Research Center is developing a distributed system to model the SCaN networks. Once complete, the system shall provide a platform that enables users to perform capacity modeling of current and prospective missions with finer-grained control of information between several simulation and modeling tools. This will enable the SCaN program to access a holistic view of its networks and simulate the effects of modifications in order to provide NASA with decisional information. The development of this capacity modeling system is managed by NASAs Strategic Center for Education, Networking, Integration, and Communication (SCENIC). Three primary third-party software tools offer their unique abilities in different stages of the simulation process. MagicDraw provides UMLSysML modeling, AGIs Systems Tool Kit simulates the physical transmission parameters and de-conflicts scheduled communication, and Riverbed Modeler (formerly OPNET) simulates communication protocols and packet-based networking. SCENIC developers are building custom software extensions to integrate these components in an end-to-end space communications modeling platform. A central control module acts as the hub for report-based messaging between client wrappers. Backend databases provide information related to mission parameters and ground station configurations, while the end user defines scenario-specific attributes for the model. The eight SCENIC interns are working under the direction of their mentors to complete an initial version of this capacity modeling system during the summer of 2015. The intern team is composed of four students in

  8. Sandia Material Model Driver

    2005-09-28

    The Sandia Material Model Driver (MMD) software package allows users to run material models from a variety of different Finite Element Model (FEM) codes in a standalone fashion, independent of the host codes. The MMD software is designed to be run on a variety of different operating system platforms as a console application. Initial development efforts have resulted in a package that has been shown to be fast, convenient, and easy to use, with substantialmore » growth potential.« less

  9. Computer Modeling Of Atomization

    NASA Technical Reports Server (NTRS)

    Giridharan, M.; Ibrahim, E.; Przekwas, A.; Cheuch, S.; Krishnan, A.; Yang, H.; Lee, J.

    1994-01-01

    Improved mathematical models based on fundamental principles of conservation of mass, energy, and momentum developed for use in computer simulation of atomization of jets of liquid fuel in rocket engines. Models also used to study atomization in terrestrial applications; prove especially useful in designing improved industrial sprays - humidifier water sprays, chemical process sprays, and sprays of molten metal. Because present improved mathematical models based on first principles, they are minimally dependent on empirical correlations and better able to represent hot-flow conditions that prevail in rocket engines and are too severe to be accessible for detailed experimentation.

  10. Modeling EERE Deployment Programs

    SciTech Connect

    Cort, Katherine A.; Hostick, Donna J.; Belzer, David B.; Livingston, Olga V.

    2007-11-08

    The purpose of this report is to compile information and conclusions gathered as part of three separate tasks undertaken as part of the overall project, “Modeling EERE Deployment Programs,” sponsored by the Planning, Analysis, and Evaluation office within the Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE). The purpose of the project was to identify and characterize the modeling of deployment programs within the EERE Technology Development (TD) programs, address improvements to modeling in the near term, and note gaps in knowledge where future research is needed.

  11. Component-specific modeling

    NASA Technical Reports Server (NTRS)

    Mcknight, R. L.

    1985-01-01

    Accomplishments are described for the second year effort of a 3-year program to develop methodology for component specific modeling of aircraft engine hot section components (turbine blades, turbine vanes, and burner liners). These accomplishments include: (1) engine thermodynamic and mission models; (2) geometry model generators; (3) remeshing; (4) specialty 3-D inelastic stuctural analysis; (5) computationally efficient solvers, (6) adaptive solution strategies; (7) engine performance parameters/component response variables decomposition and synthesis; (8) integrated software architecture and development, and (9) validation cases for software developed.

  12. 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.

  13. Vesta thermal models

    NASA Astrophysics Data System (ADS)

    Formisano, M.; Federico, C.; Coradini, A.

    Vesta thermal evolution and structural models are compared. These models, based on decay of 26Al, 60Fe and long-lived radionuclides (40K, 232Th, 235U and 238U), differ for the delay in injection (Delta td) of 26Al by the nebula in which Vesta was formed. In all models we can see the pristine formation of a metallic core followed by the differentiation of silicatic mantle and we can observe the evolution of the crust. This is in preparation of the Dawn mission that will provide us with constraints on the crust thickness and composition of the crust and underlying mantle.

  14. Acoustooptical spectrum analysis modeling

    NASA Astrophysics Data System (ADS)

    Carmody, M. J.

    1981-06-01

    A summary of Bragg deflection theory and various approaches to direct detection acoustooptic spectrum analysis (AOSA) modeling is presented. A suitable model is chosen and extended to include the effects of diffraction efficiency, transducer efficiency, irradiance profiles of incident laser illumination, aperture size of the Bragg cell, and the acoustic attenuation experienced by the acoustic wavetrain generated by the input r-f signal. A FORTRAN program is developed to model the AOSA and predict the output image plane intensity profiles. A second version of the program includes a time variable permitting dynamic simulation of the system response.

  15. Hierarchical model of matching

    NASA Technical Reports Server (NTRS)

    Pedrycz, Witold; Roventa, Eugene

    1992-01-01

    The issue of matching two fuzzy sets becomes an essential design aspect of many algorithms including fuzzy controllers, pattern classifiers, knowledge-based systems, etc. This paper introduces a new model of matching. Its principal features involve the following: (1) matching carried out with respect to the grades of membership of fuzzy sets as well as some functionals defined on them (like energy, entropy,transom); (2) concepts of hierarchies in the matching model leading to a straightforward distinction between 'local' and 'global' levels of matching; and (3) a distributed character of the model realized as a logic-based neural network.

  16. Global Core Plasma Model

    NASA Technical Reports Server (NTRS)

    Gallagher, Dennis L.; Craven, P. D.; Comfort, R. H.

    1999-01-01

    Abstract. The Global Core Plasma Model (GCPM) provides, empirically derived, core plasma density as a function of geomagnetic and solar conditions throughout the inner magnetosphere. It is continuous in value and gradient and is composed of separate models for the ionosphere, the plasmasphere, the plasmapause, the trough, and the polar cap. The relative composition of plasmaspheric H+, He+, and O+ is included in the GCPM. A blunt plasmaspheric bulge and rotation of the bulge with changing geomagnetic conditions is included. The GCPM is an amalgam of density models, intended to serve as a framework for continued improvement as new measurements become available and are used to characterize core plasma density, composition, and temperature.

  17. Modeling Hofmeister Effects.

    PubMed

    Hribar-Lee, Barbara; Vlachy, Vojko; Dill, Ken A

    2009-03-11

    A two dimensional model of water, so-called Mercedes-Benz model, was used to study effects of the size of hydrophobic solute on the insertion thermodynamics in electrolyte solutions. The model was examined by the constant pressure Monte Carlo computer simulation. The results were compared with the experimental data for noble gasses and methane in water and electrolyte solution. The influence of different ions at infinite dilution on the free energy of transfer was explored. Qualitative agreement with the experimental results was obtained. The mechanism of Hofmeister effects was proposed.

  18. Modeling Hofmeister Effects

    PubMed Central

    Hribar-Lee, Barbara; Vlachy, Vojko; Dill, Ken A.

    2009-01-01

    A two dimensional model of water, so-called Mercedes-Benz model, was used to study effects of the size of hydrophobic solute on the insertion thermodynamics in electrolyte solutions. The model was examined by the constant pressure Monte Carlo computer simulation. The results were compared with the experimental data for noble gasses and methane in water and electrolyte solution. The influence of different ions at infinite dilution on the free energy of transfer was explored. Qualitative agreement with the experimental results was obtained. The mechanism of Hofmeister effects was proposed. PMID:20161468

  19. The Finslerian wormhole models

    NASA Astrophysics Data System (ADS)

    Rahaman, Farook; Paul, Nupur; Banerjee, Ayan; De, S. S.; Ray, Saibal; Usmani, A. A.

    2016-05-01

    We present models of wormhole under the Finslerian structure of spacetime. This is a sequel of our previous work (Eur Phys J 75:564, 2015) where we constructed a toy model for compact stars based on the Finslerian spacetime geometry. In the present investigation, a wide variety of solutions are obtained, which explore the wormhole geometry by considering different choices for the form function and energy density. The solutions, like in the previous work, are revealed to be physically interesting and viable models for the explanation of wormholes as far as the background theory and literature are concerned.

  20. Perspectives on multifield models

    SciTech Connect

    Banerjee, S.

    1997-07-01

    Multifield models for prediction of nuclear reactor thermalhydraulics are reviewed from the viewpoint of their structure and requirements for closure relationships. Their strengths and weaknesses are illustrated with examples, indicating that they are effective in predicting separated and distributed flow regimes, but have problems for flows with large oscillations. Needs for multifield models are also discussed in the context of reactor operations and accident simulations. The highest priorities for future developments appear to relate to closure relationships for three-dimensional multifield models with emphasis on those needed for calculations of phase separation and entrainment/de-entrainment in complex geometries.

  1. Modeling Compressed Turbulence

    SciTech Connect

    Israel, Daniel M.

    2012-07-13

    From ICE to ICF, the effect of mean compression or expansion is important for predicting the state of the turbulence. When developing combustion models, we would like to know the mix state of the reacting species. This involves density and concentration fluctuations. To date, research has focused on the effect of compression on the turbulent kinetic energy. The current work provides constraints to help development and calibration for models of species mixing effects in compressed turbulence. The Cambon, et al., re-scaling has been extended to buoyancy driven turbulence, including the fluctuating density, concentration, and temperature equations. The new scalings give us helpful constraints for developing and validating RANS turbulence models.

  2. The inert Zee model

    NASA Astrophysics Data System (ADS)

    Longas, Robinson; Portillo, Dilia; Restrepo, Diego; Zapata, Oscar

    2016-03-01

    We study a realization of the topology of the Zee model for the generation of neutrino masses at one-loop with a minimal set of vector-like fermions. After imposing an exact Z 2 symmetry to avoid tree-level Higgs-mediated flavor changing neutral currents, one dark matter candidate is obtained from the subjacent inert doublet model, but with the presence of new co-annihilating particles. We show that the model is consistent with the constraints coming from lepton flavor violation processes, oblique parameters, dark matter and neutrino oscillation data.

  3. Dynamical model for thyroid

    NASA Astrophysics Data System (ADS)

    Rokni Lamooki, Gholam Reza; Shirazi, Amir H.; Mani, Ali R.

    2015-05-01

    Thyroid's main chemical reactions are employed to develop a mathematical model. The presented model is based on differential equations where their dynamics reflects many aspects of thyroid's behavior. Our main focus here is the well known, but not well understood, phenomenon so called as Wolff-Chaikoff effect. It is shown that the inhibitory effect of intake iodide on the rate of one single enzyme causes a similar effect as Wolff-Chaikoff. Besides this issue, the presented model is capable of revealing other complex phenomena of thyroid hormones homeostasis.

  4. Quantum causal modelling

    NASA Astrophysics Data System (ADS)

    Costa, Fabio; Shrapnel, Sally

    2016-06-01

    Causal modelling provides a powerful set of tools for identifying causal structure from observed correlations. It is well known that such techniques fail for quantum systems, unless one introduces ‘spooky’ hidden mechanisms. Whether one can produce a genuinely quantum framework in order to discover causal structure remains an open question. Here we introduce a new framework for quantum causal modelling that allows for the discovery of causal structure. We define quantum analogues for core features of classical causal modelling techniques, including the causal Markov condition and faithfulness. Based on the process matrix formalism, this framework naturally extends to generalised structures with indefinite causal order.

  5. Deconstructed Higgsless Models

    SciTech Connect

    Casalbuoni, Roberto

    2006-01-12

    We consider the possibility of constructing realistic Higgsless models within the context of deconstructed or moose models. We show that the constraints coming from the electro-weak experimental data are very severe and that it is very difficult to reconcile them with the requirement of improving the unitarity bound of the Higgsless Standard Model. On the other hand, with some fine tuning, a solution is found by delocalizing the standard fermions along the lattice line, that is allowing the fermions to couple to the moose gauge fiel0008.

  6. Modeling relativistic nuclear collisions.

    SciTech Connect

    Anderlik, C.; Magas, V.; Strottman, D.; Csernai, L. P.

    2001-01-01

    Modeling Ultra-Relativistic Heavy Ion Collisioiis at RHIC and LHC energies using a Multi Module Model is presented. The first Module is the Effective String Rope Model for the calculation of the initial stages of the reaction; the output of this module is used as the initial state for the subsequent one-fluid hydrodynainical calculation module. It is shown that such an initial state leads to the creation of the third flow component. The hydrodynamical evolution of the energy density distribution is presented for RHIC energies. The final module describing the Freeze Out; and Hadronization is also discussed.

  7. ATHENA radiation model

    SciTech Connect

    Shumway, R.W.

    1987-10-01

    The ATHENA computer program has many features that make it desirable to use as a space reactor evaluation tool. One of the missing features was a surface-to-surface thermal radiation model. A model was developed that allows any of the regular ATHENA heat slabs to radiate to any other heat slab. The view factors and surface emissivities must be specified by the user. To verify that the model was properly accounting for radiant energy transfer, two different types of test calculations were performed. Both calculations have excellent results. The updates have been used on both the INEL CDC-176 and the Livermore Cray. 7 refs., 2 figs., 6 tabs.

  8. Freeze Prediction Model

    NASA Technical Reports Server (NTRS)

    Morrow, C. T. (Principal Investigator)

    1981-01-01

    Measurements of wind speed, net irradiation, and of air, soil, and dew point temperatures in an orchard at the Rock Springs Agricultural Research Center, as well as topographical and climatological data and a description of the major apple growing regions of Pennsylvania were supplied to the University of Florida for use in running the P-model, freeze prediction program. Results show that the P-model appears to have considerable applicability to conditions in Pennsylvania. Even though modifications may have to be made for use in the fruit growing regions, there are advantages for fruit growers with the model in its present form.

  9. Aviation Safety Simulation Model

    NASA Technical Reports Server (NTRS)

    Houser, Scott; Yackovetsky, Robert (Technical Monitor)

    2001-01-01

    The Aviation Safety Simulation Model is a software tool that enables users to configure a terrain, a flight path, and an aircraft and simulate the aircraft's flight along the path. The simulation monitors the aircraft's proximity to terrain obstructions, and reports when the aircraft violates accepted minimum distances from an obstruction. This model design facilitates future enhancements to address other flight safety issues, particularly air and runway traffic scenarios. This report shows the user how to build a simulation scenario and run it. It also explains the model's output.

  10. Stochastic ontogenetic growth model

    NASA Astrophysics Data System (ADS)

    West, B. J.; West, D.

    2012-02-01

    An ontogenetic growth model (OGM) for a thermodynamically closed system is generalized to satisfy both the first and second law of thermodynamics. The hypothesized stochastic ontogenetic growth model (SOGM) is shown to entail the interspecies allometry relation by explicitly averaging the basal metabolic rate and the total body mass over the steady-state probability density for the total body mass (TBM). This is the first derivation of the interspecies metabolic allometric relation from a dynamical model and the asymptotic steady-state distribution of the TBM is fit to data and shown to be inverse power law.

  11. Modeling Hofmeister Effects.

    PubMed

    Hribar-Lee, Barbara; Vlachy, Vojko; Dill, Ken A

    2009-03-11

    A two dimensional model of water, so-called Mercedes-Benz model, was used to study effects of the size of hydrophobic solute on the insertion thermodynamics in electrolyte solutions. The model was examined by the constant pressure Monte Carlo computer simulation. The results were compared with the experimental data for noble gasses and methane in water and electrolyte solution. The influence of different ions at infinite dilution on the free energy of transfer was explored. Qualitative agreement with the experimental results was obtained. The mechanism of Hofmeister effects was proposed. PMID:20161468

  12. Expert Models and Modeling Processes Associated with a Computer-Modeling Tool

    ERIC Educational Resources Information Center

    Zhang, BaoHui; Liu, Xiufeng; Krajcik, Joseph S.

    2006-01-01

    Holding the premise that the development of expertise is a continuous process, this study concerns expert models and modeling processes associated with a modeling tool called Model-It. Five advanced Ph.D. students in environmental engineering and public health used Model-It to create and test models of water quality. Using "think aloud" technique…

  13. Lifting Body Model

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Scaled model of the Langley Personnel Launch System (PLS) Vehicle. Concept used to measure aerodynamic performance characteristics over a wide range of flow conditions and attitudes in several Langley wind tunnels.

  14. Fluidized bed combustor modeling

    NASA Technical Reports Server (NTRS)

    Horio, M.; Rengarajan, P.; Krishnan, R.; Wen, C. Y.

    1977-01-01

    A general mathematical model for the prediction of performance of a fluidized bed coal combustor (FBC) is developed. The basic elements of the model consist of: (1) hydrodynamics of gas and solids in the combustor; (2) description of gas and solids contacting pattern; (3) kinetics of combustion; and (4) absorption of SO2 by limestone in the bed. The model is capable of calculating the combustion efficiency, axial bed temperature profile, carbon hold-up in the bed, oxygen and SO2 concentrations in the bubble and emulsion phases, sulfur retention efficiency and particulate carry over by elutriation. The effects of bed geometry, excess air, location of heat transfer coils in the bed, calcium to sulfur ratio in the feeds, etc. are examined. The calculated results are compared with experimental data. Agreement between the calculated results and the observed data are satisfactory in most cases. Recommendations to enhance the accuracy of prediction of the model are suggested.

  15. Contact dynamics math model

    NASA Technical Reports Server (NTRS)

    Glaese, John R.; Tobbe, Patrick A.

    1986-01-01

    The Space Station Mechanism Test Bed consists of a hydraulically driven, computer controlled six degree of freedom (DOF) motion system with which docking, berthing, and other mechanisms can be evaluated. Measured contact forces and moments are provided to the simulation host computer to enable representation of orbital contact dynamics. This report describes the development of a generalized math model which represents the relative motion between two rigid orbiting vehicles. The model allows motion in six DOF for each body, with no vehicle size limitation. The rotational and translational equations of motion are derived. The method used to transform the forces and moments from the sensor location to the vehicles' centers of mass is also explained. Two math models of docking mechanisms, a simple translational spring and the Remote Manipulator System end effector, are presented along with simulation results. The translational spring model is used in an attempt to verify the simulation with compensated hardware in the loop results.

  16. Modeling Ionospheric Electrodynamics (Invited)

    NASA Astrophysics Data System (ADS)

    Huba, J. D.

    2009-12-01

    We present modeling results of ionospheric electrodynamics using the 3D NRL ionosphere model SAMI3. Recently, SAMI3 has been upgraded to solve the potential equation that determines the electrostatic potential from the ionospheric conductances (Pedersen and Hall) and drivers: neutral wind, gravity, and parallel current systems. We present results showing the impact of different neutral wind models (e.g., HWM93, HWM07, TIMEGCM) on the dynamics of the low- to mid-latitude ionosphere, as well as the Region 1 and 2 current systems. We point out issues and concerns with obtaining an accurate specification of the global electric field within the context of existing models.(with J. Krall, G. Joyce, S. Slinker, and G. Crowley). Research supported by NASA and ONR

  17. Modelling pulmonary blood flow

    PubMed Central

    Tawhai, Merryn H.; Burrowes, Kelly S.

    2008-01-01

    Computational model analysis is a method that has been used widely to understand and interpret complexity of interactions in the pulmonary system. Pulmonary blood transport is a multi-scale phenomenon that involves scale-dependent structure and function, therefore requiring different model assumptions for the microcirculation and the arterial or venous flows. The blood transport systems interact with the surrounding lung tissue, and are dependent on hydrostatic pressure gradients, control of vasoconstriction, and the topology and material composition of the vascular trees. This review focuses on computational models that have been developed to study the different mechanisms contributing to regional perfusion of the lung. Different models for the microcirculation and the pulmonary arteries are considered, including fractal approaches and anatomically-based methods. The studies that are reviewed illustrate the different complementary approaches that can be used to address the same physiological question of flow heterogeneity. PMID:18434260

  18. Modeling collective cell motility

    NASA Astrophysics Data System (ADS)

    Rappel, Wouter-Jan

    Eukaryotic cells often move in groups, a critical aspect of many biological and medical processes including wound healing, morphogenesis and cancer metastasis. Modeling can provide useful insights into the fundamental mechanisms of collective cell motility. Constructing models that incorporate the physical properties of the cells, however, is challenging. Here, I discuss our efforts to build a comprehensive cell motility model that includes cell membrane properties, cell-substrate interactions, cell polarity, and cell-cell interaction. The model will be applied to a variety of systems, including motion on micropatterned substrates and the migration of border cells in Drosophila. This work was supported by NIH Grant No. P01 GM078586 and NSF Grant No. 1068869.

  19. Maximally Expressive Modeling

    NASA Technical Reports Server (NTRS)

    Jaap, John; Davis, Elizabeth; Richardson, Lea

    2004-01-01

    Planning and scheduling systems organize tasks into a timeline or schedule. Tasks are logically grouped into containers called models. Models are a collection of related tasks, along with their dependencies and requirements, that when met will produce the desired result. One challenging domain for a planning and scheduling system is the operation of on-board experiments for the International Space Station. In these experiments, the equipment used is among the most complex hardware ever developed; the information sought is at the cutting edge of scientific endeavor; and the procedures are intricate and exacting. Scheduling is made more difficult by a scarcity of station resources. The models to be fed into the scheduler must describe both the complexity of the experiments and procedures (to ensure a valid schedule) and the flexibilities of the procedures and the equipment (to effectively utilize available resources). Clearly, scheduling International Space Station experiment operations calls for a maximally expressive modeling schema.

  20. GEOS-5 Modeled Clouds

    NASA Video Gallery

    This visualization shows clouds from a simulation using the Goddard Earth Observing System Model, Verison 5 (GEOS-5). The global atmospheric simulation covers a period from Feb 3, 2010 through Feb ...