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Sample records for experiment model fresh

  1. Direct-contact condensers for open-cycle OTEC applications: Model validation with fresh water experiments for structured packings

    SciTech Connect

    Bharathan, D.; Parsons, B.K.; Althof, J.A.

    1988-10-01

    The objective of the reported work was to develop analytical methods for evaluating the design and performance of advanced high-performance heat exchangers for use in open-cycle thermal energy conversion (OC-OTEC) systems. This report describes the progress made on validating a one-dimensional, steady-state analytical computer of fresh water experiments. The condenser model represents the state of the art in direct-contact heat exchange for condensation for OC-OTEC applications. This is expected to provide a basis for optimizing OC-OTEC plant configurations. Using the model, we examined two condenser geometries, a cocurrent and a countercurrent configuration. This report provides detailed validation results for important condenser parameters for cocurrent and countercurrent flows. Based on the comparisons and uncertainty overlap between the experimental data and predictions, the model is shown to predict critical condenser performance parameters with an uncertainty acceptable for general engineering design and performance evaluations. 33 refs., 69 figs., 38 tabs.

  2. Direct-contact condensers for open-cycle OTEC applications: Model validation with fresh water experiments for structured packings

    NASA Astrophysics Data System (ADS)

    Bharathan, D.; Parsons, B. K.; Althof, J. A.

    1988-10-01

    The objective of the reported work was to develop analytical methods for evaluating the design and performance of advanced high-performance heat exchangers for use in open-cycle thermal energy conversion (OC-OTEC) systems. This report describes the progress made on validating a one-dimensional, steady-state analytical computer of fresh water experiments. The condenser model represents the state of the art in direct-contact heat exchange for condensation for OC-OTEC applications. This is expected to provide a basis for optimizing OC-OTEC plant configurations. Using the model, we examined two condenser geometries, a cocurrent and a countercurrent configuration. This report provides detailed validation results for important condenser parameters for cocurrent and countercurrent flows. Based on the comparisons and uncertainty overlap between the experimental data and predictions, the model is shown to predict critical condenser performance parameters with an uncertainty acceptable for general engineering design and performance evaluations.

  3. Model experiments to establish behaviour of Yersinia enterocolitica O: 9 strains in various types of fresh dry sausage.

    PubMed

    Kleemann, J; Bergann, T

    1996-01-01

    In model experiments different kinds of raw sausages were inoculated with liquid cultures of virulent-plasmid-carrying clinical Yersinia (Y.) enterocolitica (e.) strains of the O: 9 serotype, doses being between 10(4) and 10(5) cfu g-1. The sausage samples were stored at 3-5 degrees C and 13-16 degrees C. During the first 10 d of storage the Y.e. plate count was detected with Desoxycholate-Citrate-Lactose-Sucrose Agar every day, later on in addition to it with phosphate buffer-enrichment and with enrichment according to Schiemann (1982) in intervals of several days' duration. The pH and aw values, the contents of salt and water were detected. The multitude of complexly acting factors and substances prevents obviously the proliferation of Y.e. in fresh dry sausages. Decay dynamics of Y.e. were found to be considerably affected by storage temperature. Cold storage, basically, had a conservation effect and thus delayed the dying process of model strains. Yersinia enterocolitica-contaminated fresh dry sausage may cause potential danger to consumers, because of relatively extended survival periods of the pathogen. Therefore, manufacturers are expected to observe most stringent hygienic rules of Good Manufacturing Practice. PMID:8698649

  4. Global modeling of fresh surface water temperature

    NASA Astrophysics Data System (ADS)

    Bierkens, M. F.; Eikelboom, T.; van Vliet, M. T.; Van Beek, L. P.

    2011-12-01

    Temperature determines a range of water physical properties, the solubility of oxygen and other gases and acts as a strong control on fresh water biogeochemistry, influencing chemical reaction rates, phytoplankton and zooplankton composition and the presence or absence of pathogens. Thus, in freshwater ecosystems the thermal regime affects the geographical distribution of aquatic species through their growth and metabolism, tolerance to parasites, diseases and pollution and life history. Compared to statistical approaches, physically-based models of surface water temperature have the advantage that they are robust in light of changes in flow regime, river morphology, radiation balance and upstream hydrology. Such models are therefore better suited for projecting the effects of global change on water temperature. Till now, physically-based models have only been applied to well-defined fresh water bodies of limited size (e.g., lakes or stream segments), where the numerous parameters can be measured or otherwise established, whereas attempts to model water temperature over larger scales has thus far been limited to regression type of models. Here, we present a first attempt to apply a physically-based model of global fresh surface water temperature. The model adds a surface water energy balance to river discharge modelled by the global hydrological model PCR-GLOBWB. In addition to advection of energy from direct precipitation, runoff and lateral exchange along the drainage network, energy is exchanged between the water body and the atmosphere by short and long-wave radiation and sensible and latent heat fluxes. Also included are ice-formation and its effect on heat storage and river hydraulics. We used the coupled surface water and energy balance model to simulate global fresh surface water temperature at daily time steps on a 0.5x0.5 degree grid for the period 1970-2000. Meteorological forcing was obtained from the CRU data set, downscaled to daily values with ECMWF

  5. Assessment of the recycling potential of fresh concrete waste using a factorial design of experiments.

    PubMed

    Correia, S L; Souza, F L; Dienstmann, G; Segadães, A M

    2009-11-01

    Recycling of industrial wastes and by-products can help reduce the cost of waste treatment prior to disposal and eventually preserve natural resources and energy. To assess the recycling potential of a given waste, it is important to select a tool capable of giving clear indications either way, with the least time and work consumption, as is the case of modelling the system properties using the results obtained from statistical design of experiments. In this work, the aggregate reclaimed from the mud that results from washout and cleaning operations of fresh concrete mixer trucks (fresh concrete waste, FCW) was recycled into new concrete with various water/cement ratios, as replacement of natural fine aggregates. A 3(2) factorial design of experiments was used to model fresh concrete consistency index and hardened concrete water absorption and 7- and 28-day compressive strength, as functions of FCW content and water/cement ratio, and the resulting regression equations and contour plots were validated with confirmation experiments. The results showed that the fresh concrete workability worsened with the increase in FCW content but the water absorption (5-10 wt.%), 7-day compressive strength (26-36 MPa) and 28-day compressive strength (32-44 MPa) remained within the specified ranges, thus demonstrating that the aggregate reclaimed from FCW can be recycled into new concrete mixtures with lower natural aggregate content. PMID:19596189

  6. Osmotic Power: A Fresh Look at an Old Experiment

    ERIC Educational Resources Information Center

    Dugdale, Pam

    2014-01-01

    Electricity from osmotic pressure might seem a far-fetched idea but this article describes a prototype in Norway where the osmotic pressure generated between salt and fresh water drives a turbine. This idea was applied in a student investigation, where they were tasked with researching which alternative materials could be used for the…

  7. Preparation of fresh cheese from caprine milk as a model for the reduction of allergenicity.

    PubMed

    Tomotake, Hiroyuki; Katagiri, Mitsuaki; Fujita, Masaru; Yamato, Masayuki

    2009-06-01

    Fresh cheese was prepared from caprine milk by isoelectric precipitation as a model experiment for reducing the allergenicity of milk. After acidic precipitation of casein, the beta-lactoglobulin content in curd was determined by ELISA using monoclonal antibody (MAb-beta209). The beta-lactoglobulin content was very high in the fresh cheese obtained from heat-treated (85 degrees C) bovine or caprine milk, while that obtained from untreated milk contained none of this protein. Taking it into account that caprine milk has only a small amount of alpha(s1)-casein, one of the major bovine milk allergens, the caprine fresh cheese sterilized after processing by precipitation may be useful as a protein source of low allergenicity. PMID:19602841

  8. Methodology for modeling the migration of EOR chemicals in fresh water aquifers

    SciTech Connect

    Royce, B.; Garrell, M.; Kahn, A.; Kaplan, E.

    1983-11-01

    The objective of this study is to develop a method for modeling the transport of EOR chemicals accidentally released to fresh water aquifers. Six examples involving hypothetical releases of EOR chemicals at surrogate aquifer sites are used to illustrate the application of this method. Typical injection rates and concentrations of EOR chemicals used at current or proposed projects were obtained from the literature and used as the basis for the hypothetical accidents. Four surrogate aquifer sites were selected from States where chemical flooding methods are employed. Each site is based on real hydrological data but presented in such a way to avoid identification with existing EOR fields. A significant amount of data is required to model ground water systems. The hypothetical examples help to indicate the type of data needed. The computer results illustrate that high levels of contamination are possible for many years. In addition, due to these high levels of contamination, it is possible for contaminants to migrate offsite of the EOR field. There are a variety of pathways through which EOR chemicals could be accidentally released to fresh water aquifers during normal EOR operations. There is insufficient EOR experience to date, however, to forecast risks accurately. 119 references, 10 figures, 9 tables.

  9. Analysis of fresh fuel critical experiments appropriate for burnup credit validation

    SciTech Connect

    DeHart, M.D.; Bowman, S.M.

    1995-10-01

    The ANS/ANS-8.1 standard requires that calculational methods used in determining criticality safety limits for applications outside reactors be validated by comparison with appropriate critical experiments. This report provides a detailed description of 34 fresh fuel critical experiments and their analyses using the SCALE-4.2 code system and the 27-group ENDF/B-IV cross-section library. The 34 critical experiments were selected based on geometry, material, and neutron interaction characteristics that are applicable to a transportation cask loaded with pressurized-water-reactor spent fuel. These 34 experiments are a representative subset of a much larger data base of low-enriched uranium and mixed-oxide critical experiments. A statistical approach is described and used to obtain an estimate of the bias and uncertainty in the calculational methods and to predict a confidence limit for a calculated neutron multiplication factor. The SCALE-4.2 results for a superset of approximately 100 criticals are included in uncertainty analyses, but descriptions of the individual criticals are not included.

  10. Numerical Modelling and Ejecta Distribution Analysis of a Martian Fresh Crater

    NASA Astrophysics Data System (ADS)

    Lucchetti, A.; Cremonese, G.; Cambianica, P.; Daubar, I.; McEwen, A. S.; Re, C.

    2015-12-01

    Images taken by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter reveal fresh craters on Mars that are known to be recent as they are constrained by before and after images (Daubar et al., 2013). In particular, on Nov. 19, 2013 an image acquired by HiRISE, ESP_034285_1835, observed a 25 m diameter fresh crater located at 3.7° N, 53.4° E. This impact occurred between July 2010 and May 2012, as constrained by Context camera (CTX) images. Because the terrain where the crater formed is dusty, the fresh crater appears blue in the enhanced color of the HiRISE image, due to removal of the reddish dust in that area. We analyze this crater using the iSALE shock physics code (Amsden et al., 1980, Collins et al., 2004, Ivanov et al., 1997, Melosh et al., 1992, Wünnemann et al., 2006) to model the formation of this impact structure which is ~25 m in diameter and ~ 2.5 - 3 m in depth. These values are obtained from the DTM profile we have generated. We model the Martian surface considering different target compositions as regolith and fractured basalt rock and we based our simulations on a basalt projectile with a porosity of 10% (which is derived from the average of the meteorite types proposed by Britt et al., 2002) that hits the Martian surface with a beginning velocity equal to 7 km/s (Le Feuvre & Wieczorek, 2011) and an impact angle of 90°. The projectile size is around 1 m and it is estimated from the comparison between the DTM profile and the profiles obtained by numerical modelling. The primary objective of this analysis is the detailed study of the ejecta, in fact we will track the ejecta coming from the simulation and compare them to the ejecta distribution computed on the image (the ejecta reached a distance of more than 15 km). From the matching of the simulated ejecta with their real distribution, we will be able to understand the goodness of the simulation and also put constraints on the target material.

  11. Modeling fresh water lens damage and recovery on atolls after storm-wave washover.

    PubMed

    Chui, Ting Fong May; Terry, James P

    2012-01-01

    The principal natural source of fresh water on scattered coral atolls throughout the tropical Pacific Ocean is thin unconfined groundwater lenses within islet substrates. Although there are many threats to the viability of atoll fresh water lenses, salinization caused by large storm waves washing over individual atoll islets is poorly understood. In this study, a mathematical modeling approach is used to examine the immediate responses, longer-term behavior, and subsequent (partial) recovery of a Pacific atoll fresh water lens after saline damage caused by cyclone-generated wave washover under different scenarios. Important findings include: (1) the saline plume formed by a washover event mostly migrates downward first through the top coral sand and gravel substrate, but then exits the aquifer to the ocean laterally through the more permeable basement limestone; (2) a lower water table position before the washover event, rather than a longer duration of storm washover, causes more severe damage to the fresh water lens; (3) relatively fresher water can possibly be found as a preserved horizon in the deeper part of an aquifer after disturbance, especially if the fresh water lens extends into the limestone under normal conditions; (4) post-cyclone accumulation of sea water in the central depression (swamp) of an atoll islet prolongs the later stage of fresh water lens recovery. PMID:21883195

  12. Numerical modeling of fresh concrete flow through porous medium

    NASA Astrophysics Data System (ADS)

    Kolařík, F.; Patzák, B.; Zeman, J.

    2016-06-01

    The paper focuses on a numerical modeling of a non-Newtonian fluid flow in a porous domain. It presents combination of a homogenization approach to obtain permeability from the underlying micro-structure with coupling of a Stokes and Darcy flow through the interface on the macro level. As a numerical method we employed the Finite Element method. The results obtained from the homogenization approach are validated against fully resolved solution computed by direct numerical simulation.

  13. Evaluation of hands-on seminar for reduced port surgery using fresh porcine cadaver model

    PubMed Central

    Poudel, Saseem; Kurashima, Yo; Shichinohe, Toshiaki; Kitashiro, Shuji; Kanehira, Eiji; Hirano, Satoshi

    2016-01-01

    BACKGROUND: The use of various biological and non-biological simulators is playing an important role in training modern surgeons with laparoscopic skills. However, there have been few reports of the use of a fresh porcine cadaver model for training in laparoscopic surgical skills. The purpose of this study was to report on a surgical training seminar on reduced port surgery using a fresh cadaver porcine model and to assess its feasibility and efficacy. MATERIALS AND METHODS: The hands-on seminar had 10 fresh porcine cadaver models and two dry boxes. Each table was provided with a unique access port and devices used in reduced port surgery. Each group of 2 surgeons spent 30 min at each station, performing different tasks assisted by the instructor. The questionnaire survey was done immediately after the seminar and 8 months after the seminar. RESULTS: All the tasks were completed as planned. Both instructors and participants were highly satisfied with the seminar. There was a concern about the time allocated for the seminar. In the post-seminar survey, the participants felt that the number of reduced port surgeries performed by them had increased. CONCLUSION: The fresh cadaver porcine model requires no special animal facility and can be used for training in laparoscopic procedures. PMID:27279391

  14. Measured and Modeled Humidification Factors of Fresh Smoke Particles From Biomass Burning: Role of Inorganic Constituents

    SciTech Connect

    Hand, Jenny L.; Day, Derek E.; McMeeking, Gavin M.; Levin, Ezra; Carrico, Christian M.; Kreidenweis, Sonia M.; Malm, William C.; Laskin, Alexander; Desyaterik, Yury

    2010-07-09

    During the 2006 FLAME study (Fire Laboratory at Missoula Experiment), laboratory burns of biomass fuels were performed to investigate the physico-chemical, optical, and hygroscopic properties of fresh biomass smoke. As part of the experiment, two nephelometers simultaneously measured dry and humidified light scattering coefficients (bsp(dry) and bsp(RH), respectively) in order to explore the role of relative humidity (RH) on the optical properties of biomass smoke aerosols. Results from burns of several biomass fuels showed large variability in the humidification factor (f(RH) = bsp(RH)/bsp(dry)). Values of f(RH) at RH=85-90% ranged from 1.02 to 2.15 depending on fuel type. We incorporated measured chemical composition and size distribution data to model the smoke hygroscopic growth to investigate the role of inorganic and organic compounds on water uptake for these aerosols. By assuming only inorganic constituents were hygroscopic, we were able to model the water uptake within experimental uncertainty, suggesting that inorganic species were responsible for most of the hygroscopic growth. In addition, humidification factors at 85-90% RH increased for smoke with increasing inorganic salt to carbon ratios. Particle morphology as observed from scanning electron microscopy revealed that samples of hygroscopic particles contained soot chains either internally or externally mixed with inorganic potassium salts, while samples of weak to non-hygroscopic particles were dominated by soot and organic constituents. This study provides further understanding of the compounds responsible for water uptake by young biomass smoke, and is important for accurately assessing the role of smoke in climate change studies and visibility regulatory efforts.

  15. 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.

  16. Hydrochemical Impacts of CO2 Leakage on Fresh Groundwater: a Field Scale Experiment

    NASA Astrophysics Data System (ADS)

    Lions, J.; Gal, F.; Gombert, P.; Lafortune, S.; Darmoul, Y.; Prevot, F.; Grellier, S.; Squarcioni, P.

    2013-12-01

    One of the questions related to the emerging technology for Carbon Geological Storage concerns the risk of CO2 migration beyond the geological storage formation. In the event of leakage toward the surface, the CO2 might affect resources in neighbouring formations (geothermal or mineral resources, groundwater) or even represent a hazard for human activities at the surface or in the subsurface. In view of the preservation of the groundwater resources mainly for human consumption, this project studies the potential hydrogeochemical impacts of CO2 leakage on fresh groundwater quality. One of the objectives is to characterize the bio-geochemical mechanisms that may impair the quality of fresh groundwater resources in case of CO2 leakage. To reach the above mentioned objectives, this project proposes a field experiment to characterize in situ the mechanisms that could impact the water quality, the CO2-water-rock interactions and also to improve the monitoring methodology by controlled CO2 leakage in shallow aquifer. The tests were carried out in an experimental site in the chalk formation of the Paris Basin. The site is equipped with an appropriate instrumentation and was previously characterized (8 piezometers, 25 m deep and 4 piezairs 11 m deep). The injection test was preceded by 6 months of monitoring in order to characterize hydrodynamics and geochemical baselines of the site (groundwater, vadose and soil). Leakage into groundwater is simulated via the injection of a small quantity of food-grade CO2 (~20 kg dissolved in 10 m3 of water) in the injection well at a depth of about 20 m. A plume of dissolved CO2 is formed and moves downward according to the direction of groundwater flow and probably by degassing in part to the surface. During the injection test, hydrochemical monitoring of the aquifer is done in situ and by sampling. The parameters monitored in the groundwater are the piezometric head, temperature, pH and electrical conductivity. Analysis on water

  17. A novel reflectance-based model for evaluating chlorophyll concentration of fresh and water-stressed leaves

    NASA Astrophysics Data System (ADS)

    Lin, C.; Popescu, S. C.; Huang, S. C.; Chen, Y. C.; Chang, P. T.; Wen, H. L.

    2013-11-01

    Water deficit can cause chlorophyll degradation which decreases foliar chlorophyll concentration (Chls). Few studies investigated the effectiveness of spectral indices under water stress conditions. Chlorophyll meters have been extensively used for a wide variety of leaf chlorophyll and nitrogen estimations. Since a chlorophyll meter works based on the sensing of leaves absorptance and transmittance, the reading of chlorophyll concentration will be affected by changes in transmittance as if there is a water deficit in leaves. The overall objective of this paper was to develop a novel and reliable reflectance-based model for estimating Chls of fresh and water stressed leaves using the reflectance at the absorption bands of chlorophyll a and b and the red edge spectrum. Three independent experiments were designed to collect data from three leaf sample sets for the construction and validation of Chls estimation models. First, a reflectance experiment was conducted to collect foliar Chls and reflectance of leaves with varying water stress using the ASD FieldSpec spectroradiometer. Second, a chlorophyll meter (SPAD-502) experiment was carried out to collect foliar Chls and meter reading. These two datasets were separately used for developing reflectance-based or absorptance-based Chls estimation models using linear and nonlinear regression analysis. Suitable models were suggested mainly based on the coefficient of determination (R2). Finally, an experiment was conducted to collect the third dataset for the validation of Chls models using the root mean squared error (RMSE) and the mean absolute error (MAE). In all of the experiments, the observations (real values) of the foliar Chls were extracted from acetone solution and determined by using a Hitachi U-2000 spectrophotometer. The spectral indices in the form of reflectance ratio/difference/slope derived from the chlb absorption bands (ρ645 and ρ455) provided Chls estimates with RMSE around 0.40-0.55 mg g-1 for both

  18. A novel reflectance-based model for evaluating chlorophyll concentrations of fresh and water-stressed leaves

    NASA Astrophysics Data System (ADS)

    Lin, C.; Popescu, S. C.; Huang, S. C.; Chang, P. T.; Wen, H. L.

    2015-01-01

    Water deficits can cause chlorophyll degradation which decreases the total concentration of chlorophyll a and b (Chls). Few studies have investigated the effectiveness of spectral indices under water-stressed conditions. Chlorophyll meters have been extensively used for a wide variety of leaf chlorophyll and nitrogen estimations. Since a chlorophyll meter works by sensing leaves absorptance and transmittance, the reading of chlorophyll concentration will be affected by changes in transmittance as if there were a water deficit in the leaves. The overall objective of this paper was to develop a novel and reliable reflectance-based model for estimating Chls of fresh and water-stressed leaves using the reflectance at the absorption bands of chlorophyll a and b and the red edge spectrum. Three independent experiments were designed to collect data from three leaf sample sets for the construction and validation of Chls estimation models. First, a reflectance experiment was conducted to collect foliar Chls and reflectance of leaves with varying water stress using the ASD FieldSpec spectroradiometer. Second, a chlorophyll meter (SPAD-502) experiment was carried out to collect foliar Chls and meter readings. These two data sets were separately used for developing reflectance-based or absorptance-based Chls estimation models using linear and nonlinear regression analysis. Suitable models were suggested mainly based on the coefficient of determination (R2). Finally, an experiment was conducted to collect the third data set for the validation of Chls models using the root mean squared error (RMSE) and the mean absolute error (MAE). In all of the experiments, the observations (real values) of the foliar Chls were extracted from acetone solution and determined by using a Hitachi U-2000 spectrophotometer. The spectral indices in the form of reflectance ratio/difference/slope derived from the Chl b absorption bands (ρ645 and ρ455) provided Chls estimates with RMSE around 0

  19. A Technique to Perfuse Cadavers that Extends the Useful Life of Fresh Tissues: The Duke Experience

    ERIC Educational Resources Information Center

    Messmer, Caroline; Kellogg, Ryan T.; Zhang, Yixin; Baiak, Andresa; Leiweke, Clinton; Marcus, Jeffrey R.; Levin, L. Scott; Zenn, Michael R.; Erdmann, Detlev

    2010-01-01

    The demand for laboratory-based teaching and training is increasing worldwide as medical training and education confront the pressures of shorter training time and rising costs. This article presents a cost-effective perfusion technique that extends the useful life of fresh tissue. Refrigerated cadavers are preserved in their natural state for up…

  20. Philip Morris toxicological experiments with fresh sidestream smoke: more toxic than mainstream smoke

    PubMed Central

    Schick, S; Glantz, S

    2005-01-01

    Background: Exposure to secondhand smoke causes lung cancer; however, there are little data in the open literature on the in vivo toxicology of fresh sidestream cigarette smoke to guide the debate about smoke-free workplaces and public places. Objective: To investigate the unpublished in vivo research on sidestream cigarette smoke done by Philip Morris Tobacco Company during the 1980s at its Institut für Biologische Forschung (INBIFO). Methods: Analysis of internal tobacco industry documents now available at the University of California San Francisco Legacy Tobacco Documents Library and other websites. Results: Inhaled fresh sidestream cigarette smoke is approximately four times more toxic per gram total particulate matter (TPM) than mainstream cigarette smoke. Sidestream condensate is approximately three times more toxic per gram and two to six times more tumourigenic per gram than mainstream condensate by dermal application. The gas/vapour phase of sidestream smoke is responsible for most of the sensory irritation and respiratory tract epithelium damage. Fresh sidestream smoke inhibits normal weight gain in developing animals. In a 21day exposure, fresh sidestream smoke can cause damage to the respiratory epithelium at concentrations of 2 µg/l TPM. Damage to the respiratory epithelium increases with longer exposures. The toxicity of whole sidestream smoke is higher than the sum of the toxicities of its major constituents. Conclusion: Fresh sidestream smoke at concentrations commonly encountered indoors is well above a 2 µg/m3 reference concentration (the level at which acute effects are unlikely to occur), calculated from the results of the INBIFO studies, that defines acute toxicity to humans. Smoke-free public places and workplaces are the only practical way to protect the public health from the toxins in sidestream smoke. PMID:16319363

  1. Use of a miniature laboratory fresh cheese model for investigating antimicrobial activities.

    PubMed

    Van Tassell, M L; Ibarra-Sánchez, L A; Takhar, S R; Amaya-Llano, S L; Miller, M J

    2015-12-01

    Hispanic-style fresh cheeses, such as queso fresco, have relatively low salt content, high water activity, and near neutral pH, which predisposes them to growth of Listeria monocytogenes. Biosafety constraints limit the incorporation of L. monocytogenes into cheeses manufactured via traditional methods in challenge studies, so few have focused on in situ testing of novel antimicrobials in fresh cheeses. We have developed a modular, miniaturized laboratory-scale queso fresco model for testing the incorporation of novel antilisterials. We have demonstrated the assessment of the antilisterials nisin and ferulic acid, alone and in combination, at various levels. Our results support the inhibitory effects of ferulic acid in cheese, against both L. monocytogenes and its common surrogate Listeria innocua, and we provide preliminary evaluation of its consumer acceptability. PMID:26454301

  2. Analysis of subcritical experiments using fresh and spent research reactor fuel assemblies

    NASA Astrophysics Data System (ADS)

    Zino, John Frederick

    1999-11-01

    This research investigated the concepts associated with crediting the burnup of spent nuclear fuel assemblies for the purposes of criticality safety. To accomplish this, a collaborative experimental research program was undertaken between Westinghouse, the University of Missouri Research Reactor (MURR) facility and Oak Ridge National Laboratory (ORNL). The purpose of the program was to characterize the subcritical behavior of a small array of fresh and spent MURR fuel assemblies using the 252Cf Source-driven noise technique. An aluminum test rig was built which was capable of holding up to four, highly enriched (93.15 wt.% 235U) MURR fuel assemblies in a 2 x 2 array. The rig was outfitted with one source and four detector drywells which allowed researchers to perform active neutron noise measurements on the array of fuel assemblies. The 1 atmosphere gas 3He neutron detectors used to perform the measurements were quenched with CF4 gas to allow improved discrimination of the neutron signals in the very high gamma-ray fields associated with spent fuel (˜8000 R/hr). In addition, the detector drywells were outfitted with 1″ lead collars to provide additional gamma-ray shielding from the spent fuel. Reactivity changes were induced in the subcritical lattice by replacing individual fresh assemblies (in a 4-assembly array) with spent assemblies of known, maximum burnup (143 Mw-D). The absolute and relative measured reactivity changes were then compared to those predicted by three-dimensional Monte Carlo calculations. The purpose of these comparisons was to investigate the accuracy of modern transport theory depletion calculations to accurately simulate the reactivity effects of burnup in spent nuclear fuel. A total of seven subcritical measurements were performed at the MURR reactor facility on July 20th and 27th, 1998. These measurements generated several estimates of prompt neutron decay constants (alpha) and ratios of spectral densities through frequency correlations

  3. Laparoscopic training model using fresh human cadavers without the establishment of penumoperitoneum

    PubMed Central

    Imakuma, Ernesto Sasaki; Ussami, Edson Yassushi; Meyer, Alberto

    2016-01-01

    BACKGROUND: Laparoscopy is a well-established alternative to open surgery for treating many diseases. Although laparoscopy has many advantages, it is also associated with disadvantages, such as slow learning curves and prolonged operation time. Fresh frozen cadavers may be an interesting resource for laparoscopic training, and many institutions have access to cadavers. One of the main obstacles for the use of cadavers as a training model is the difficulty in introducing a sufficient pneumoperitoneum to distend the abdominal wall and provide a proper working space. The purpose of this study was to describe a fresh human cadaver model for laparoscopic training without requiring a pneumoperitoneum. MATERIALS AND METHODS AND RESULTS: A fake abdominal wall device was developed to allow for laparoscopic training without requiring a pneumoperitoneum in cadavers. The device consists of a table-mounted retractor, two rail clamps, two independent frame arms, two adjustable handle and rotating features, and two frames of the abdominal wall. A handycam is fixed over a frame arm, positioned and connected through a USB connection to a television and dissector; scissors and other laparoscopic materials are positioned inside trocars. The laparoscopic procedure is thus simulated. CONCLUSION: Cadavers offer a very promising and useful model for laparoscopic training. We developed a fake abdominal wall device that solves the limitation of space when performing surgery on cadavers and removes the need to acquire more costly laparoscopic equipment. This model is easily accessible at institutions in developing countries, making it one of the most promising tools for teaching laparoscopy. PMID:27073318

  4. Turbulence modeling and experiments

    NASA Technical Reports Server (NTRS)

    Shabbir, Aamir

    1992-01-01

    The best way of verifying turbulence is to do a direct comparison between the various terms and their models. The success of this approach depends upon the availability of the data for the exact correlations (both experimental and DNS). The other approach involves numerically solving the differential equations and then comparing the results with the data. The results of such a computation will depend upon the accuracy of all the modeled terms and constants. Because of this it is sometimes difficult to find the cause of a poor performance by a model. However, such a calculation is still meaningful in other ways as it shows how a complete Reynolds stress model performs. Thirteen homogeneous flows are numerically computed using the second order closure models. We concentrate only on those models which use a linear (or quasi-linear) model for the rapid term. This, therefore, includes the Launder, Reece and Rodi (LRR) model; the isotropization of production (IP) model; and the Speziale, Sarkar, and Gatski (SSG) model. Which of the three models performs better is examined along with what are their weaknesses, if any. The other work reported deal with the experimental balances of the second moment equations for a buoyant plume. Despite the tremendous amount of activity toward the second order closure modeling of turbulence, very little experimental information is available about the budgets of the second moment equations. Part of the problem stems from our inability to measure the pressure correlations. However, if everything else appearing in these equations is known from the experiment, pressure correlations can be obtained as the closing terms. This is the closest we can come to in obtaining these terms from experiment, and despite the measurement errors which might be present in such balances, the resulting information will be extremely useful for the turbulence modelers. The purpose of this part of the work was to provide such balances of the Reynolds stress and heat

  5. Modelling the influence of time and temperature on the respiration rate of fresh oyster mushrooms.

    PubMed

    Azevedo, Sílvia; Cunha, Luís M; Fonseca, Susana C

    2015-12-01

    The respiration rate of mushrooms is an important indicator of postharvest senescence. Storage temperature plays a major role in their rate of respiration and, therefore, in their postharvest life. In this context, reliable predictions of respiration rates are critical for the development of modified atmosphere packaging that ultimately will maximise the quality of the product to be presented to consumers. This work was undertaken to study the influence of storage time and temperature on the respiration rate of oyster mushrooms. For that purpose, oyster mushrooms were stored at constant temperatures of 2, 6, 10, 14 and 18 ℃ under ambient atmosphere. Respiration rate data were measured with 8-h intervals up to 240 h. A decrease of respiration rate was found after cutting of the carpophores. Therefore, time effect on respiration rate was modelled using a first-order decay model. The results also show the positive influence of temperature on mushroom respiration rate. The model explaining the effect of time on oyster mushroom's respiration rate included the temperature dependence according to the Arrhenius equation, and the inclusion of a parameter describing the decrease of the respiration rate, from the initial time until equilibrium. These yielded an overall model that fitted well to the experimental data. Moreover, results show that the overall model is useful to predict respiration rate of oyster mushrooms at different temperatures and times, using the initial respiration rate of mushrooms. Furthermore, predictive modelling can be relevant for the choice of an appropriate packaging system for fresh oyster mushrooms. PMID:25339381

  6. Numerical modelling and hydrochemical characterisation of a fresh-water lens in the Belgian coastal plain

    NASA Astrophysics Data System (ADS)

    Vandenbohede, A.; Lebbe, L.

    2002-05-01

    The distribution of fresh and salt water in coastal aquifers is influenced by many processes. The influence of aquifer heterogeneity and human interference such as land reclamation is illustrated in the Belgian coastal plain where, around A.D. 1200, the reclamation of a tidally influenced environment was completed. The aquifer, which was filled with salt water, was thereafter freshened. The areal distribution of peat, clay, silt and sand influences the general flow and distribution of fresh and salt water along with the drainage pattern and results in the development of fresh-water lenses. The water quality in and around the fresh-water lenses below an inverted tidal channel ridge is surveyed. The hydrochemical evolution of the fresh water lens is reconstructed, pointing to cation exchange, solution of calcite and the oxidation of organic material as the major chemical reactions. The formation and evolution of the fresh water lens is modelled using a two-dimensional density-dependent solute transport model and the sensitivity of drainage and conductivities are studied. Drainage level mainly influences the depth of the fresh-water lens, whereas the time of formation is mainly influenced by conductivity. Résumé. La répartition de l'eau douce et de l'eau salée dans les aquifères littoraux est influencée par de nombreux mécanismes. L'influence de l'hétérogénéité de l'aquifère et des interférences anthropiques telles que la mise en valeur des terres est illustrée par la plaine côtière belge où, depuis l'an 1200, on a mis en valeur un environnement soumis aux marées. L'aquifère, qui contenait de l'eau salée, contient maintenant de l'eau douce. La distribution spatiale de tourbe, d'argile, de silt et de sable joue un rôle dans l'écoulement général et dans la répartition de l'eau douce et de l'eau salée le long du réseau de drainage et produit des lentilles d'eau douce. La qualité de l'eau dans et autour des lentilles d'eau douce sous une lev

  7. Electron-beam inactivation of a norovirus surrogate in fresh produce and model systems.

    PubMed

    Sanglay, Gabriel C; Li, Jianrong; Uribe, R M; Lee, Ken

    2011-07-01

    Norovirus remains the leading cause of foodborne illness, but there is no effective intervention to eliminate viral contaminants in fresh produce. Murine norovirus 1 (MNV-1) was inoculated in either 100 ml of liquid or 100 g of food. The inactivation of MNV-1 by electron-beam (e-beam), or high-energy electrons, at varying doses was measured in model systems (phosphate-buffered saline [PBS], Dulbecco's modified Eagle's medium [DMEM]) or from fresh foods (shredded cabbage, diced strawberries). E-beam was applied at a current of 1.5 mA, with doses of 0, 2, 4, 6, 8, 10, and 12 kGy. The surviving viral titer was determined by plaque assays in RAW 264.7 cells. In PBS and DMEM, e-beam at 0 and 2 kGy provided less than a 1-log reduction of virus. At doses of 4, 6, 8, 10, and 12 kGy, viral inactivation in PBS ranged from 2.37 to 6.40 log, while in DMEM inactivation ranged from 1.40 to 3.59 log. Irradiation of inoculated cabbage showed up to a 1-log reduction at 4 kGy, and less than a 3-log reduction at 12 kGy. On strawberries, less than a 1-log reduction occurred at doses up to 6 kGy, with a maximum reduction of 2.21 log at 12 kGy. These results suggest that a food matrix might provide increased survival for viruses. In foods, noroviruses are difficult to inactivate because of the protective effect of the food matrix, their small sizes, and their highly stable viral capsid. PMID:21740718

  8. Finite-difference model to simulate the areal flow of saltwater and fresh water separated by an interface

    USGS Publications Warehouse

    Mercer, James W.; Larson, S.P.; Faust, Charles R.

    1980-01-01

    Model documentation is presented for a two-dimensional (areal) model capable of simulating ground-water flow of salt water and fresh water separated by an interface. The partial differential equations are integrated over the thicknesses of fresh water and salt water resulting in two equations describing the flow characteristics in the areal domain. These equations are approximated using finite-difference techniques and the resulting algebraic equations are solved for the dependent variables, fresh water head and salt water head. An iterative solution method was found to be most appropriate. The program is designed to simulate time-dependent problems such as those associated with the development of coastal aquifers, and can treat water-table conditions or confined conditions with steady-state leakage of fresh water. The program will generally be most applicable to the analysis of regional aquifer problems in which the zone between salt water and fresh water can be considered a surface (sharp interface). Example problems and a listing of the computer code are included. (USGS).

  9. Involving regional expertise in nationwide modeling for adequate prediction of climate change effects on different demands for fresh water

    NASA Astrophysics Data System (ADS)

    de Lange, W. J.

    2014-05-01

    Wim J. de Lange, Geert F. Prinsen, Jacco H. Hoogewoud, Ab A Veldhuizen, Joachim Hunink, Erik F.W. Ruijgh, Timo Kroon Nationwide modeling aims to produce a balanced distribution of climate change effects (e.g. harm on crops) and possible compensation (e.g. volume fresh water) based on consistent calculation. The present work is based on the Netherlands Hydrological Instrument (NHI, www.nhi.nu), which is a national, integrated, hydrological model that simulates distribution, flow and storage of all water in the surface water and groundwater systems. The instrument is developed to assess the impact on water use on land-surface (sprinkling crops, drinking water) and in surface water (navigation, cooling). The regional expertise involved in the development of NHI come from all parties involved in the use, production and management of water, such as waterboards, drinking water supply companies, provinces, ngo's, and so on. Adequate prediction implies that the model computes changes in the order of magnitude that is relevant to the effects. In scenarios related to drought, adequate prediction applies to the water demand and the hydrological effects during average, dry, very dry and extremely dry periods. The NHI acts as a part of the so-called Deltamodel (www.deltamodel.nl), which aims to predict effects and compensating measures of climate change both on safety against flooding and on water shortage during drought. To assess the effects, a limited number of well-defined scenarios is used within the Deltamodel. The effects on demand of fresh water consist of an increase of the demand e.g. for surface water level control to prevent dike burst, for flushing salt in ditches, for sprinkling of crops, for preserving wet nature and so on. Many of the effects are dealt with by regional and local parties. Therefore, these parties have large interest in the outcome of the scenario analyses. They are participating in the assessment of the NHI previous to the start of the analyses

  10. Modelling the response of fresh groundwater to climate and vegetation changes in coral islands

    NASA Astrophysics Data System (ADS)

    Comte, Jean-Christophe; Join, Jean-Lambert; Banton, Olivier; Nicolini, Eric

    2014-12-01

    In coral islands, groundwater is a crucial freshwater resource for terrestrial life, including human water supply. Response of the freshwater lens to expected climate changes and subsequent vegetation alterations is quantified for Grande Glorieuse, a low-lying coral island in the Western Indian Ocean. Distributed models of recharge, evapotranspiration and saltwater phytotoxicity are integrated into a variable-density groundwater model to simulate the evolution of groundwater salinity. Model results are assessed against field observations including groundwater and geophysical measurements. Simulations show the major control currently exerted by the vegetation with regards to the lens morphology and the high sensitivity of the lens to climate alterations, impacting both quantity and salinity. Long-term changes in mean sea level and climatic conditions (rainfall and evapotranspiration) are predicted to be responsible for an average increase in salinity approaching 140 % (+8 kg m-3) when combined. In low-lying areas with high vegetation density, these changes top +300 % (+10 kg m-3). However, due to salinity increase and its phytotoxicity, it is shown that a corollary drop in vegetation activity can buffer the alteration of fresh groundwater. This illustrates the importance of accounting for vegetation dynamics to study groundwater in coral islands.

  11. Murine Model of Buckwheat Allergy by Intragastric Sensitization with Fresh Buckwheat Flour Extract

    PubMed Central

    Oh, Sejo; Lee, Kisun; Jang, Young-Ju; Sohn, Myung-Hyun; Lee, Kyoung-En; Kim, Kyu-Earn

    2005-01-01

    Food allergies affect about 4% of the Korean population, and buckwheat allergy is one of the most severe food allergies in Korea. The purpose of the present study was to develop a murine model of IgE-mediated buckwheat hypersensitivity induced by intragastric sensitization. Young female C3H/HeJ mice were sensitized and challenged intragastricly with fresh buckwheat flour (1, 5, 25 mg/dose of proteins) mixed in cholera toxin, followed by intragastric challenge. Anaphylactic reactions, antigen-specific antibodies, splenocytes proliferation assays and cytokine productions were evaluated. Oral buckwheat challenges of sensitized mice provoked anaphylactic reactions such as severe scratch, perioral/periorbital swellings, or decreased activity. Reactions were associated with elevated levels of buckwheat-specific IgE antibodies. Splenocytes from buckwheat allergic mice exhibited significantly greater proliferative responses to buckwheat than non-allergic mice. Buckwheat-stimulated IL-4, IL-5, and INF-γ productions were associated with elevated levels of buckwheat-specific IgE in sensitized mice. In this model, 1 mg and 5 mg dose of sensitization produced almost the same degree of Th2-directed immune response, however, a 25 mg dose showed blunted antibody responses. In conclusion, we developed IgE-mediated buckwheat allergy by intragastric sensitization and challenge, and this model could provide a good tool for future studies. PMID:16100445

  12. Neonatal transfusion models to determine the impact of using fresh red blood cells on inventory and exposure

    PubMed Central

    Quinn, Kerry; Quinn, Maureen; Moreno, Christina; Soundar, Esther; Teruya, Jun; Hui, Shiu-Ki

    2015-01-01

    Background Data on age of blood and its impact on donor exposure and inventory in the paediatric setting are lacking. The standard of practice of reserving a specific red blood cell (RBC) unit for neonates who may require repeat transfusions is unique to the paediatric setting. Requiring transfusion of fresher RBC units may increase the exposure of neonates to multiple units and negatively affect the supply of fresh RBC. We constructed a transfusion model based on a 6 months of retrospective neonatal transfusion data at our institution. Materials and methods All neonates (≤4 months old) at Texas Children’s Hospital who received a RBC transfusion from June to November 2011 were included and RBC transfusion data were compiled. The age of blood at the time of each RBC transfusion was recorded. These data were reviewed to calculate exposure and inventory impact if each transfusion had been restricted to RBC either ≤7 or ≤14 days old at transfusion. Results A total of 216 neonates received 938 RBC transfusions. Of these, 393 (42%) were fresh RBC (≤14 days old), even without a required age guideline. Requiring fresh (≤14 days) RBC for all transfusions in this period would have resulted in 70 additional fresh units and one or more additional exposures in 44 patients. Requiring fresher (≤7 days old) RBC would have resulted in an additional 147 units and. one or more additional exposures in 54 patients. Discussion The more conservative model of fresh (≤7 days old) RBC would greatly increase fresh RBC inventory requirements, and 25% of transfused neonates would require additional RBC exposure. Based on retrospective data and the two transfusion models, it can be concluded that requiring RBC ≤14 days old for neonatal transfusion would best balance the use of fresher RBC with the smallest increase in patient exposure (20%) and minimum impact on the RBC inventory. PMID:26192783

  13. Fresh Kills leachate treatment and minimization study: Volume 2, Modeling, monitoring and evaluation. Final report

    SciTech Connect

    Fillos, J.; Khanbilvardi, R.

    1993-09-01

    The New York City Department of Sanitation is developing a comprehensive landfill leachate management plan for the Fresh Kills landfill, located on the western shore of Staten Island, New York. The 3000-acre facility, owned and operated by the City of New York, has been developed into four distinct mounds that correspond to areas designated as Sections 1/9, 2/8, 3/4 and 6/7. In developing a comprehensive leachate management plan, the estimating leachate flow rates is important in designing appropriate treatment alternatives to reduce the offsite migration that pollutes both surface water and groundwater resources.Estimating the leachate flow rates from Sections 1/9 and 6/7 was given priority using an available model, hydrologic evaluation of landfill performance (HELP), and a new model, flow investigation for landfill leachate (FILL). The field-scale analysis for leachate flow included data collection of the leachate mound-level from piezometers and monitoring wells installed on-site, for six months period. From the leachate mound-head contours and flow-gradients, Leachate flow rates were computed using Darcy`s Law.

  14. Litchi freshness rapid non-destructive evaluating method using electronic nose and non-linear dynamics stochastic resonance model

    PubMed Central

    Ying, Xiaoguo; Liu, Wei; Hui, Guohua

    2015-01-01

    In this paper, litchi freshness rapid non-destructive evaluating method using electronic nose (e-nose) and non-linear stochastic resonance (SR) was proposed. EN responses to litchi samples were continuously detected for 6 d Principal component analysis (PCA) and non-linear stochastic resonance (SR) methods were utilized to analyze EN detection data. PCA method could not totally discriminate litchi samples, while SR signal-to-noise ratio (SNR) eigen spectrum successfully discriminated all litchi samples. Litchi freshness predictive model developed using SNR eigen values shows high predictive accuracy with regression coefficients R2 = 0 .99396. PMID:25920547

  15. A comprehensive sharp-interface simulation-optimization model for fresh and saline groundwater management in coastal areas

    NASA Astrophysics Data System (ADS)

    Park, Namsik; Shi, Lei

    2015-09-01

    Both fresh and saline groundwater may be of some value to coastal communities. A comprehensive simulation-optimization model was developed to identify optimal solutions for managing both types of groundwater in coastal areas. The model may be used for conventional management problems of fresh groundwater development and of seawater intrusion control. In addition, the model can be used for problems of concurrent development of fresh and saline/brackish groundwater for beneficial uses. A set of hypothetical examples is given to demonstrate the applicability of the proposed model. In the protection of an over-exploiting freshwater pumping well, the saltwater pumping scheme was less efficient than the freshwater injection scheme. Although the former scheme may be more advantageous in some limited cases, the latter should be considered first as it retains more freshwater in the aquifer. The example of the concurrent development of fresh and brackish groundwater exhibited two different sets of optimal solutions: one with a large amount of freshwater and a small amount of brackish water with high salinity, and the other with a small amount of freshwater and a large amount of brackish water with low salinity.

  16. A production planning model considering uncertain demand using two-stage stochastic programming in a fresh vegetable supply chain context.

    PubMed

    Mateo, Jordi; Pla, Lluis M; Solsona, Francesc; Pagès, Adela

    2016-01-01

    Production planning models are achieving more interest for being used in the primary sector of the economy. The proposed model relies on the formulation of a location model representing a set of farms susceptible of being selected by a grocery shop brand to supply local fresh products under seasonal contracts. The main aim is to minimize overall procurement costs and meet future demand. This kind of problem is rather common in fresh vegetable supply chains where producers are located in proximity either to processing plants or retailers. The proposed two-stage stochastic model determines which suppliers should be selected for production contracts to ensure high quality products and minimal time from farm-to-table. Moreover, Lagrangian relaxation and parallel computing algorithms are proposed to solve these instances efficiently in a reasonable computational time. The results obtained show computational gains from our algorithmic proposals in front of the usage of plain CPLEX solver. Furthermore, the results ensure the competitive advantages of using the proposed model by purchase managers in the fresh vegetables industry. PMID:27386288

  17. A new conceptual model on the fate and controls of fresh and pyrolized plant litter decomposition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The leaching of dissolved organic matter (DOM) from fresh and pyrolyzed aboveground plant inputs to the soil is a major pathway by which decomposing aboveground plant material contributes to soil organic matter formation. Understanding how aboveground plant input chemical traits control the partiti...

  18. CFD modeling to improve safe and efficient distribution of chlorine dioxide gas for packaging fresh produce

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The efficiency of the packaging system in inactivating food borne pathogens and prolonging the shelf life of fresh-cut produce is influenced by the design of the package apart from material and atmospheric conditions. Three different designs were considered to determine a specific package design ens...

  19. We Think You Need a Vacation...: The Discipline Model at Fresh Youth Initiatives

    ERIC Educational Resources Information Center

    Afterschool Matters, 2003

    2003-01-01

    Fresh Youth Initiative (FYI) is a youth development organization based in the Washington Heights-Inwood section of Manhattan. The group's mission is to support and encourage the efforts of neighborhood young people and their families to design and carry out community service and social action projects, develop leadership skills, fulfill their…

  20. An artificial intelligence approach for modeling volume and fresh weight of callus - A case study of cumin (Cuminum cyminum L.).

    PubMed

    Mansouri, Ali; Fadavi, Ali; Mortazavian, Seyed Mohammad Mahdi

    2016-05-21

    Cumin (Cuminum cyminum Linn.) is valued for its aroma and its medicinal and therapeutic properties. A supervised feedforward artificial neural network (ANN) trained with back propagation algorithms, was applied to predict fresh weight and volume of Cuminum cyminum L. calli. Pearson correlation coefficient was used to evaluate input/output dependency of the eleven input parameters. Area, feret diameter, minor axis length, perimeter and weighted density parameters were chosen as input variables. Different training algorithms, transfer functions, number of hidden nodes and training iteration were studied to find out the optimum ANN structure. The network with conjugate gradient fletcher-reeves (CGF) algorithm, tangent sigmoid transfer function, 17 hidden nodes and 2000 training epochs was selected as the final ANN model. The final model was able to predict the fresh weight and volume of calli more precisely relative to multiple linear models. The results were confirmed by R(2)≥0.89, R(i)≥0.94 and T value ≥0.86. The results for both volume and fresh weight values showed that almost 90% of data had an acceptable absolute error of ±5%. PMID:26987421

  1. Modelling spoilage of fresh turbot and evaluation of a time-temperature integrator (TTI) label under fluctuating temperature.

    PubMed

    Nuin, Maider; Alfaro, Begoña; Cruz, Ziortza; Argarate, Nerea; George, Susie; Le Marc, Yvan; Olley, June; Pin, Carmen

    2008-10-31

    Kinetic models were developed to predict the microbial spoilage and the sensory quality of fresh fish and to evaluate the efficiency of a commercial time-temperature integrator (TTI) label, Fresh Check(R), to monitor shelf life. Farmed turbot (Psetta maxima) samples were packaged in PVC film and stored at 0, 5, 10 and 15 degrees C. Microbial growth and sensory attributes were monitored at regular time intervals. The response of the Fresh Check device was measured at the same temperatures during the storage period. The sensory perception was quantified according to a global sensory indicator obtained by principal component analysis as well as to the Quality Index Method, QIM, as described by Rahman and Olley [Rahman, H.A., Olley, J., 1984. Assessment of sensory techniques for quality assessment of Australian fish. CSIRO Tasmanian Regional Laboratory. Occasional paper n. 8. Available from the Australian Maritime College library. Newnham. Tasmania]. Both methods were found equally valid to monitor the loss of sensory quality. The maximum specific growth rate of spoilage bacteria, the rate of change of the sensory indicators and the rate of change of the colour measurements of the TTI label were modelled as a function of temperature. The temperature had a similar effect on the bacteria, sensory and Fresh Check kinetics. At the time of sensory rejection, the bacterial load was ca. 10(5)-10(6) cfu/g. The end of shelf life indicated by the Fresh Check label was close to the sensory rejection time. The performance of the models was validated under fluctuating temperature conditions by comparing the predicted and measured values for all microbial, sensory and TTI responses. The models have been implemented in a Visual Basic add-in for Excel called "Fish Shelf Life Prediction (FSLP)". This program predicts sensory acceptability and growth of spoilage bacteria in fish and the response of the TTI at constant and fluctuating temperature conditions. The program is freely

  2. Introducing a Fresh Cadaver Model for Ultrasound-guided Central Venous Access Training in Undergraduate Medical Education

    PubMed Central

    Miller, Ryan; Ho, Hang; Ng, Vivienne; Tran, Melissa; Rappaport, Douglas; Rappaport, William J.A.; Dandorf, Stewart J.; Dunleavy, James; Viscusi, Rebecca; Amini, Richard

    2016-01-01

    Introduction Over the past decade, medical students have witnessed a decline in the opportunities to perform technical skills during their clinical years. Ultrasound-guided central venous access (USG-CVA) is a critical procedure commonly performed by emergency medicine, anesthesia, and general surgery residents, often during their first month of residency. However, the acquisition of skills required to safely perform this procedure is often deficient upon graduation from medical school. To ameliorate this lack of technical proficiency, ultrasound simulation models have been introduced into undergraduate medical education to train venous access skills. Criticisms of simulation models are the innate lack of realistic tactile qualities, as well as the lack of anatomical variances when compared to living patients. The purpose of our investigation was to design and evaluate a life-like and reproducible training model for USG-CVA using a fresh cadaver. Methods This was a cross-sectional study at an urban academic medical center. An 18-point procedural knowledge tool and an 18-point procedural skill evaluation tool were administered during a cadaver lab at the beginning and end of the surgical clerkship. During the fresh cadaver lab, procedure naïve third-year medical students were trained on how to perform ultrasound-guided central venous access of the femoral and internal jugular vessels. Preparation of the fresh cadaver model involved placement of a thin-walled latex tubing in the anatomic location of the femoral and internal jugular vein respectively. Results Fifty-six third-year medical students participated in this study during their surgical clerkship. The fresh cadaver model provided high quality and lifelike ultrasound images despite numerous cannulation attempts. Technical skill scores improved from an average score of 3 to 12 (p<0.001) and procedural knowledge scores improved from an average score of 4 to 8 (p<0.001). Conclusion The use of this novel cadaver

  3. Experimental evaluation of four infiltration models for calcareous soil irrigated with treated untreated grey water and fresh water

    NASA Astrophysics Data System (ADS)

    Gharaibeh, M. A.; Eltaif, N. I.; Alrababah, M. A.; Alhamad, M. N.

    2009-04-01

    Infiltration is vital for both irrigated and rainfed agriculture. The knowledge of infiltration characteristics of a soil is the basic information required for designing an efficient irrigation system. The objective of the present study was to model soil infiltration using four models: Green and Ampt, Horton, Kostaikov and modified Kostiakov. Infiltration tests were conducted on field plot irrigated with treated, untreated greywater and fresh water. The field water infiltration data used in these models were based on double ring infiltrometer tests conducted for 4 h. The algebraic parameters of the infiltration models and nonlinear least squares regression were fitted using measured infiltration time [I (t)] data. Among process-based infiltration models, the Horton model performed best and matched the measured I (t) data with lower sum of squares (SS).

  4. Evaluation of food protective property of five natural products using fresh-cut apple slice model.

    PubMed

    Hakkim, Faruk Lumanul; Mathiraj; Essa, Musthafa Mohamed; Arivazhagan, Girija; Guizani, Nejib; Hyuk, Song

    2012-01-01

    The present study evaluated the antioxidant (AA), antimicrobial and preservation effects of five plant derived natural products viz., Rosmarinic Acid (RA), p-Coumaric Acid (pCA), Trans-Cinnamic Acid (TCA), Hydroxyphenyllactic Acid (HPA) and Caffeic acid (CA) along with synthetic compounds (Ascorbic acid, gallic acid, citric acid and BHA) on fresh cut apple slices. Antimicrobial efficacy of these compounds against Bacillus licheniformis, Pseudomonas vulgaris, Shigella boydii, Salmonella typhi, Staphylococcus aureus, Listeria monocytogenes and Escherichia coli was found to be concentration dependent with the maximum inhibition observed at 500 microg mL(-1). A considerable AA potential of these compounds was observed in in vitro based assay system, with RA exhibiting significantly higher effect than the other compounds at 500 microg mL(-1). Furthermore the compounds at 500 microg mL(-1) significantly reduced the browning, maintained the acidic pH and restricted growth of L. monocytogenes even after 10 days of treatment. Ethanol accumulation in fresh cut apple slices increased significantly throughout the experimental period. Over all RA exhibited maximum effect in all the food preservation parameters studied suggesting that it has synchronized food protection effect and can be recommended as food additive. PMID:22530437

  5. Using density difference to store fresh water in saline subsurface

    NASA Astrophysics Data System (ADS)

    van Ginkel, M.; Olsthoorn, Th. N.; des Tombe, B.

    2012-04-01

    The storage of fresh water in the subsurface for later recovery and use (Aquifer Storage and Recovery) is becoming more and more important in the coming decades for seasonal or emergency storage, especially in the light of climate change and increasing population. However, fresh water storage in a saline subsurface poses a challenge: the initially vertical interface between injected fresh and native salt water is unstable and tends to rotate. The injected fresh water tends to float upward on top of native salt water, where it becomes hard or impossible to recover at a later stage. A wide body of literature exists about this buoyancy effect that is caused by the density difference between fresh and salt water. Yet, very few papers focus on solutions to this problem. In this paper we propose a storage principle to overcome this buoyancy problem by actually using the density difference to keep the fresh water in place, by combining salt water extraction and impermeable barriers. This technique seems promising and could solve many local fresh water storage problems. It is especially applicable in shallow water table aquifers for the storage of fresh water below parks and arable land or for seasonal storage of desalinated water. We performed laboratory-scale experiments and numerical modelling to study the dynamic behaviour of a fresh water bubble stored in saline subsurface using the technique of salt water extraction and impermeable barriers; including effects of operation dynamics, groundwater flow, and diffusion, dispersion and density differences.

  6. A comparison of the coupled fresh water-salt water flow and the Ghyben-Herzberg sharp interface approaches to modeling of transient behavior in coastal aquifer systems

    USGS Publications Warehouse

    Essaid, H.I.

    1986-01-01

    A quasi-three dimensional finite difference model which simulates coupled, fresh water and salt water flow, separated by a sharp interface, is used to investigate the effects of storage characteristics, transmissivity, boundary conditions and anisotropy on the transient responses of such flow systems. The magnitude and duration of the departure of aquifer response from the behavior predicted using the Ghyben-Herzberg, one-fluid approach is a function of the ease with which flow can be induced in the salt water region. In many common hydrogeologic settings short-term fresh water head responses, and transitional responses between short-term and long-term, can only be realistically reproduced by including the effects of salt water flow on the dynamics of coastal flow systems. The coupled fresh water-salt water flow modeling approach is able to reproduce the observed annual fresh water head response of the Waialae aquifer of southeastern Oahu, Hawaii. ?? 1986.

  7. Validation of a predictive model coupling gas transfer and microbial growth in fresh food packed under modified atmosphere.

    PubMed

    Guillard, V; Couvert, O; Stahl, V; Hanin, A; Denis, C; Huchet, V; Chaix, E; Loriot, C; Vincelot, T; Thuault, D

    2016-09-01

    Predicting microbial safety of fresh products in modified atmosphere packaging implies to take into account the dynamic of O2, CO2 and N2 exchanges in the system and its effect on microbial growth. In this paper a mechanistic model coupling gas transfer and predictive microbiology was validated using dedicated challenge-tests performed on poultry meat, fresh salmon and processed cheese, inoculated with either Listeria monocytogenes or Pseudomonas fluorescens and packed in commercially used packaging materials (tray + lid films). The model succeeded in predicting the relative variation of O2, CO2 and N2 partial pressure in headspace and the growth of the studied microorganisms without any parameter identification. This work highlighted that the respiration of the targeted microorganism itself and/or that of the naturally present microflora could not be neglected in most of the cases, and could, in the particular case of aerobic microbes contribute to limit the growth by removing all residual O2 in the package. This work also confirmed the low sensitivity of L. monocytogenes toward CO2 while that of P. fluorescens permitted to efficiently prevent its growth by choosing the right combination of packaging gas permeability value and initial % of CO2 initially flushed in the pack. PMID:27217358

  8. An Application of the PMI Model at the Project Level: Evaluation of the ESEA Title IV C Fresh Start Minischool Project.

    ERIC Educational Resources Information Center

    Harrison, Patricia C.

    The Planning, Monitoring, and Implementation Model (PMI) was developed to provide a model for systematic evaluation of educational programs to determine their effectiveness in achieving goals and objectives. This paper demonstrates the applicability of the PMI model at the project level. Fresh Start Minischool at Ballou High School (District of…

  9. Debris flows: Experiments and modelling

    NASA Astrophysics Data System (ADS)

    Turnbull, Barbara; Bowman, Elisabeth T.; McElwaine, Jim N.

    2015-01-01

    Debris flows and debris avalanches are complex, gravity-driven currents of rock, water and sediments that can be highly mobile. This combination of component materials leads to a rich morphology and unusual dynamics, exhibiting features of both granular materials and viscous gravity currents. Although extreme events such as those at Kolka Karmadon in North Ossetia (2002) [1] and Huascarán (1970) [2] strongly motivate us to understand how such high levels of mobility can occur, smaller events are ubiquitous and capable of endangering infrastructure and life, requiring mitigation. Recent progress in modelling debris flows has seen the development of multiphase models that can start to provide clues of the origins of the unique phenomenology of debris flows. However, the spatial and temporal variations that debris flows exhibit make this task challenging and laboratory experiments, where boundary and initial conditions can be controlled and reproduced, are crucial both to validate models and to inspire new modelling approaches. This paper discusses recent laboratory experiments on debris flows and the state of the art in numerical models.

  10. Methodology for modeling the disinfection efficiency of fresh-cut leafy vegetables wash water applied on peracetic acid combined with lactic acid.

    PubMed

    Van Haute, S; López-Gálvez, F; Gómez-López, V M; Eriksson, Markus; Devlieghere, F; Allende, Ana; Sampers, I

    2015-09-01

    A methodology to i) assess the feasibility of water disinfection in fresh-cut leafy greens wash water and ii) to compare the disinfectant efficiency of water disinfectants was defined and applied for a combination of peracetic acid (PAA) and lactic acid (LA) and comparison with free chlorine was made. Standardized process water, a watery suspension of iceberg lettuce, was used for the experiments. First, the combination of PAA+LA was evaluated for water recycling. In this case disinfectant was added to standardized process water inoculated with Escherichia coli (E. coli) O157 (6logCFU/mL). Regression models were constructed based on the batch inactivation data and validated in industrial process water obtained from fresh-cut leafy green processing plants. The UV254(F) was the best indicator for PAA decay and as such for the E. coli O157 inactivation with PAA+LA. The disinfection efficiency of PAA+LA increased with decreasing pH. Furthermore, PAA+LA efficacy was assessed as a process water disinfectant to be used within the washing tank, using a dynamic washing process with continuous influx of E. coli O157 and organic matter in the washing tank. The process water contamination in the dynamic process was adequately estimated by the developed model that assumed that knowledge of the disinfectant residual was sufficient to estimate the microbial contamination, regardless the physicochemical load. Based on the obtained results, PAA+LA seems to be better suited than chlorine for disinfecting process wash water with a high organic load but a higher disinfectant residual is necessary due to the slower E. coli O157 inactivation kinetics when compared to chlorine. PMID:26065727

  11. [Extending Hyperspectral Detecting Model of pH in Fresh Pork to New Breeds].

    PubMed

    Liu, Jiao; Li, Xiao-yu; Jin, Rui; Xu, Sen-miao; Ku, Jing

    2015-07-01

    Calibration transfer is an effective approach to solve model invalidation problems caused by the change of instruments or the prediction samples. However, most studies on calibration transfer were based on different instruments, and models were established by Near Infrared Spectroscopy. In this study, hyperspectral detecting model of pork pH value was established, and in order to enhance the applicability of model to different breeds of pork samples; a new transfer algorithm based on spectra Mahalanobis distance, sync correction of spectrum and prediction value (CSPV), has been proposed, and was compared with model updating method. Equations with correlation coefficient of prediction (rp) > or = 0.837 and residual prediction deviation (RPD) > or = 1.9 were considered as applicable to predict pork quality. In this paper, three breeds, duchangda, maojia and linghao pork were researched, and a pH detecting model of duchangda (the primary breed) was established using partial least squares (PLS) regression method with r(c) of 0.922, r(p) of 0.904, root mean squared error of cross validation (RMSECV) of 0.045, root mean squared error of prediction (RMSEP) of 0.046 and RPD of 2.380. However, the prediction of the model to samples from maojia and linghao breeds (the secondary breeds) was very poor with rp of 0. 770 and 0.731 respectively, RMSEP of 0.111 and 0.209, RPD reached only 1.533 and 1.234 separately. Obviously, the PLS model of duchangda was unable to achieve the prediction to maojia and linghao samples. With the transformation of CSPV algorithm to duchangda model, only 9 and 10 standard samples from maojia and linghao breeds were used respectively, the prediction ability was improved with r(c) of 0.889 and 0.900, RPD grew to 2.071 and 2.231, which met the requirement of r(p) 0.837 and RPD > or = 1.9. While with model updating method, when 11 and 9 representative samples fromitaojia and linghao breeds were added to calibration set of duchangda model, r(c) increased

  12. Involving regional expertise in nationwide modeling for adequate prediction of climate change effects on different demands for fresh water

    NASA Astrophysics Data System (ADS)

    de Lange, Wim; Prinsen, Geert.; Hoogewoud, Jacco; Veldhuizen, Ab; Ruijgh, Erik; Kroon, Timo

    2013-04-01

    Nationwide modeling aims to produce a balanced distribution of climate change effects (e.g. harm on crops) and possible compensation (e.g. volume fresh water) based on consistent calculation. The present work is based on the Netherlands Hydrological Instrument (NHI, www.nhi.nu), which is a national, integrated, hydrological model that simulates distribution, flow and storage of all water in the surface water and groundwater systems. The instrument is developed to assess the impact on water use on land-surface (sprinkling crops, drinking water) and in surface water (navigation, cooling). The regional expertise involved in the development of NHI come from all parties involved in the use, production and management of water, such as waterboards, drinking water supply companies, provinces, ngo's, and so on. Adequate prediction implies that the model computes changes in the order of magnitude that is relevant to the effects. In scenarios related to drought, adequate prediction applies to the water demand and the hydrological effects during average, dry, very dry and extremely dry periods. The NHI acts as a part of the so-called Deltamodel (www.deltamodel.nl), which aims to predict effects and compensating measures of climate change both on safety against flooding and on water shortage during drought. To assess the effects, a limited number of well-defined scenarios is used within the Deltamodel. The effects on demand of fresh water consist of an increase of the demand e.g. for surface water level control to prevent dike burst, for flushing salt in ditches, for sprinkling of crops, for preserving wet nature and so on. Many of the effects are dealt with? by regional and local parties. Therefore, these parties have large interest in the outcome of the scenario analyses. They are participating in the assessment of the NHI previous to the start of the analyses. Regional expertise is welcomed in the calibration phase of NHI. It aims to reduce uncertainties by improving the

  13. Modeling of microgravity combustion experiments

    NASA Technical Reports Server (NTRS)

    Buckmaster, John

    1993-01-01

    Modeling plays a vital role in providing physical insights into behavior revealed by experiment. The program at the University of Illinois is designed to improve our understanding of basic combustion phenomena through the analytical and numerical modeling of a variety of configurations undergoing experimental study in NASA's microgravity combustion program. Significant progress has been made in two areas: (1) flame-balls, studied experimentally by Ronney and his co-workers; (2) particle-cloud flames studied by Berlad and his collaborators. Additional work is mentioned below. NASA funding for the U. of Illinois program commenced in February 1991 but work was initiated prior to that date and the program can only be understood with this foundation exposed. Accordingly, we start with a brief description of some key results obtained in the pre - 2/91 work.

  14. How Famine Started in Somalia: A Simple Model of Fresh Water Use

    NASA Astrophysics Data System (ADS)

    Gustafson, K. C.; Motesharrei, S.; Miralles-Wilhelm, F. R.; Kalnay, E.; Rivas, J.; Freshwater Modeling Team

    2011-12-01

    Water is the origin of life on our planet and therefore the most valued and essential natural resource for sustaining life on earth. Human uses of freshwater include not only drinking, washing, and other daily domestic activities, but also manufacturing, energy production, agriculture, aquaculture, etc. Though our planet is 97% water, only a minute portion of this is available as freshwater to be used for anthropogenic necessities and the rate at which the natural system can filter and replenish the freshwater supply cannot compete with the rate of demand. That is why special attention must be given to availability of freshwater at present time and in future. We constructed a fairly elementary model of the water cycle while we were working on a more sophisticated water model that includes several additional details. Upon introducing data from different regions of the world (including United States) into our simple model and running simulations, we can gain insight into the future of water sources and availability of freshwater. In particular, we are able to simulate how drought can result in famine, a catastrophe currently taking place in certain areas of Somalia.

  15. Fresh clouds: A parameterized updraft method for calculating cloud densities in one-dimensional models

    NASA Astrophysics Data System (ADS)

    Wong, Michael H.; Atreya, Sushil K.; Kuhn, William R.; Romani, Paul N.; Mihalka, Kristen M.

    2015-01-01

    Models of cloud condensation under thermodynamic equilibrium in planetary atmospheres are useful for several reasons. These equilibrium cloud condensation models (ECCMs) calculate the wet adiabatic lapse rate, determine saturation-limited mixing ratios of condensing species, calculate the stabilizing effect of latent heat release and molecular weight stratification, and locate cloud base levels. Many ECCMs trace their heritage to Lewis (Lewis, J.S. [1969]. Icarus 10, 365-378) and Weidenschilling and Lewis (Weidenschilling, S.J., Lewis, J.S. [1973]. Icarus 20, 465-476). Calculation of atmospheric structure and gas mixing ratios are correct in these models. We resolve errors affecting the cloud density calculation in these models by first calculating a cloud density rate: the change in cloud density with updraft length scale. The updraft length scale parameterizes the strength of the cloud-forming updraft, and converts the cloud density rate from the ECCM into cloud density. The method is validated by comparison with terrestrial cloud data. Our parameterized updraft method gives a first-order prediction of cloud densities in a “fresh” cloud, where condensation is the dominant microphysical process. Older evolved clouds may be better approximated by another 1-D method, the diffusive-precipitative Ackerman and Marley (Ackerman, A.S., Marley, M.S. [2001]. Astrophys. J. 556, 872-884) model, which represents a steady-state equilibrium between precipitation and condensation of vapor delivered by turbulent diffusion. We re-evaluate observed cloud densities in the Galileo Probe entry site (Ragent, B. et al. [1998]. J. Geophys. Res. 103, 22891-22910), and show that the upper and lower observed clouds at ∼0.5 and ∼3 bars are consistent with weak (cirrus-like) updrafts under conditions of saturated ammonia and water vapor, respectively. The densest observed cloud, near 1.3 bar, requires unexpectedly strong updraft conditions, or higher cloud density rates. The cloud

  16. Functional Characterization and Drug Response of Freshly Established Patient-Derived Tumor Models with CpG Island Methylator Phenotype

    PubMed Central

    Maletzki, Claudia; Huehns, Maja; Knapp, Patrick; Waukosin, Nancy; Klar, Ernst; Prall, Friedrich; Linnebacher, Michael

    2015-01-01

    Patient-individual tumor models constitute a powerful platform for basic and translational analyses both in vitro and in vivo. However, due to the labor-intensive and highly time-consuming process, only few well-characterized patient-derived cell lines and/or corresponding xenografts exist. In this study, we describe successful generation and functional analysis of novel tumor models from patients with sporadic primary colorectal carcinomas (CRC) showing CpG island methylator phenotype (CIMP). Initial DNA fingerprint analysis confirmed identity with the patient in all four cases. These freshly established cells showed characteristic features associated with the CIMP-phenotype (HROC40: APCwt, TP53mut, KRASmut; 3/8 marker methylated; HROC43: APCmut, TP53mut, KRASmut; 4/8 marker methylated; HROC60: APCwt, TP53mut, KRASwt; 4/8 marker methylated; HROC183: APCmut, TP53mut, KRASmut; 6/8 marker methylated). Cell lines were of epithelial origin (EpCAM+) with distinct morphology and growth kinetics. Response to chemotherapeutics was quite individual between cells, with stage I-derived cell line HROC60 being most susceptible towards standard clinically approved chemotherapeutics (e.g. 5-FU, Irinotecan). Of note, most cell lines were sensitive towards “non-classical” CRC standard drugs (sensitivity: Gemcitabin > Rapamycin > Nilotinib). This comprehensive analysis of tumor biology, genetic alterations and assessment of chemosensitivity towards a broad range of (chemo-) therapeutics helps bringing forward the concept of personalized tumor therapy. PMID:26618628

  17. Need Of Modelling Radionuclide Transport In Fresh Water Lake System, Subject To Indian Context

    SciTech Connect

    Desai, Hiral; Christian, R. A.

    2010-10-26

    The operations of nuclear facilities results in low level radioactive effluents, which are required to be released into the environment. The effluents from nuclear installations are treated adequately and then released in a controlled manner under strict compliance of discharge criteria. The effluents released from installations into environment undergo dilution and dispersion. However, there is possibility of concentration by the biological process in the environment. Aquatic ecosystems are very complex webs of physical, chemical and biological interactions. It is generally both costly and laborious to describe their characteristics, and to predict them is even harder. Every aquatic ecosystem is unique, and yet it is impossible to study each system in the detail necessary for case-by-case assessment of ecological threats. In this situation, quantitative mathematical models are essential to predict, to guide assessment and to direct interventions.

  18. Experiments beyond the standard model

    SciTech Connect

    Perl, M.L.

    1984-09-01

    This paper is based upon lectures in which I have described and explored the ways in which experimenters can try to find answers, or at least clues toward answers, to some of the fundamental questions of elementary particle physics. All of these experimental techniques and directions have been discussed fully in other papers, for example: searches for heavy charged leptons, tests of quantum chromodynamics, searches for Higgs particles, searches for particles predicted by supersymmetric theories, searches for particles predicted by technicolor theories, searches for proton decay, searches for neutrino oscillations, monopole searches, studies of low transfer momentum hadron physics at very high energies, and elementary particle studies using cosmic rays. Each of these subjects requires several lectures by itself to do justice to the large amount of experimental work and theoretical thought which has been devoted to these subjects. My approach in these tutorial lectures is to describe general ways to experiment beyond the standard model. I will use some of the topics listed to illustrate these general ways. Also, in these lectures I present some dreams and challenges about new techniques in experimental particle physics and accelerator technology, I call these Experimental Needs. 92 references.

  19. Factors controlling the configuration of the fresh-saline water interface in the Dead Sea coastal aquifers: Synthesis of TDEM surveys and numerical groundwater modeling

    USGS Publications Warehouse

    Yechieli, Y.; Kafri, U.; Goldman, M.; Voss, C.I.

    2001-01-01

    TDEM (time domain electromagnetic) traverses in the Dead Sea (DS) coastal aquifer help to delineate the configuration of the interrelated fresh-water and brine bodies and the interface in between. A good linear correlation exists between the logarithm of TDEM resistivity and the chloride concentration of groundwater, mostly in the higher salinity range, close to that of the DS brine. In this range, salinity is the most important factor controlling resistivity. The configuration of the fresh-saline water interface is dictated by the hydraulic gradient, which is controlled by a number of hydrological factors. Three types of irregularities in the configuration of fresh-water and saline-water bodies were observed in the study area: 1. Fresh-water aquifers underlying more saline ones ("Reversal") in a multi-aquifer system. 2. "Reversal" and irregular residual saline-water bodies related to historical, frequently fluctuating DS base level and respective interfaces, which have not undergone complete flushing. A rough estimate of flushing rates may be obtained based on knowledge of the above fluctuations. The occurrence of salt beds is also a factor affecting the interface configuration. 3. The interface steepens towards and adjacent to the DS Rift fault zone. Simulation analysis with a numerical, variable-density flow model, using the US Geological Survey's SUTRA code, indicates that interface steep- ening may result from a steep water-level gradient across the zone, possibly due to a low hydraulic conductivity in the immediate vicinity of the fault.

  20. Changes in polyphenol profiles and color composition of freshly fermented model wine due to pulsed electric field, enzymes and thermovinification pretreatments.

    PubMed

    El Darra, Nada; Turk, Mohammad F; Ducasse, Marie-Agnès; Grimi, Nabil; Maroun, Richard G; Louka, Nicolas; Vorobiev, Eugène

    2016-03-01

    This work compares the effects of three pretreatments techniques: pulsed electric fields (PEFs), enzymes treatment (ET) and thermovinification (TV) on the improving of extraction of main phenolic compounds, color characteristics (L(∗)a(∗)b(∗)), and composition (copigmentation, non-discolored pigments) of freshly fermented model wine from Cabernet Sauvignon variety. The pretreatments produced differences in the wines, with the color of the freshly fermented model wine obtained from PEF and TV pretreated musts being the most different with an increase of 56% and 62%, respectively, compared to the control, while the color only increased by 22% for ET. At the end of the alcoholic fermentation, the contents of anthocyanins for all the pretreatments were not statistically different. However, for the content of total phenolics and total flavonols, PEF and TV were statistically different, but ET was not statistically different. The contents of flavonols in musts pretreated by PEF and TV were significantly higher comparing to the control. An increase of 48% and 97% was noted respectively, and only 4% for ET. A similar result was observed for the total phenolics with an increase by 18% and 32% respectively for PEF and TV, and only 3% for ET comparing to the control. The results suggest that the higher intensity and the difference of color composition between the control and pretreated freshly fermented model wines were not related only to a higher content of residual native polyphenols in these freshly fermented model wines. Other phenomena such as copigmentation and formation of derived pigments may be favored by these pretreatments. PMID:26471638

  1. Microbial Biomass in the Rhizosphere: Model Development and Column Experiments

    NASA Astrophysics Data System (ADS)

    Sung, K.; Corapcioglu, M.; Kim, J.

    2001-12-01

    Microorganisms are important factor in the major contribution to degradation of organic contaminants in bioremediation as well as in phytoremediation. Enhanced biodegradation takes place in soils if there are increased numbers of microorganisms stimulated by additional substrates such as root exudates, exogenous substrate addition, and indigenous substrate conversion. Roots can thus greatly affect the concentration and distribution of microbial biomass in soils. A mathematical model is presented that can be applied to various bioremediation methods, especially phytoremediation, for simulating microbial biomass changes in soils. Experiments were conducted in field lysimeters containing freshly contaminated soil and sown with Johnsongrass. The microbial biomass concentrations from rhizosphere soil, bulk soil, and unplanted soil were estimated for one year using an incubation-fumigation method. The mathematical model was applied to the field data on microbial biomass. To investigate the model behavior, numerical experiments were conducted before applying the model to actual field data. The results show good correlation between simulated and experimental data. Microbial effects on contaminant degradation in phytoremediation can be smaller than that resulting from additional substrates due to indigenous conversion or exogenous supply. However, the addition of exogenous substrates in phytoremediation can increase remediation efficiency in the early period when the roots may not produce exudates rapidly. Cultivation before planting may also increase microbial activity to accelerate degradation of contaminants in soil.

  2. Sonoluminescence: Experiments and models (Review)

    NASA Astrophysics Data System (ADS)

    Borisenok, V. A.

    2015-05-01

    Three models of the sonoluminescence source formation are considered: the shock-free compression model, the shock wave model, and the polarization model. Each of them is tested by experimental data on the size of the radiating region and the angular radiation pattern; the shape and duration of the radiation pulse; the influence of the type of liquid, gas composition, surfactants, sound frequency, and temperature of the liquid on the radiation intensity; the characteristics of the shock wave in the liquid; and the radiation spectra. It is shown that the most adequate qualitative explanation of the entire set of experimental data is given by the polarization model. Methods for verifying the model are proposed. Publications devoted to studying the possibility a thermonuclear fusion reaction in a cavitation system are reviewed.

  3. Experiments on a Model Eye

    ERIC Educational Resources Information Center

    Arell, Antti; Kolari, Samuli

    1978-01-01

    Explains a laboratory experiment dealing with the optical features of the human eye. Shows how to measure the magnification of the retina and the refractive anomaly of the eye could be used to measure the refractive power of the observer's eye. (GA)

  4. An experiment with interactive planning models

    NASA Technical Reports Server (NTRS)

    Beville, J.; Wagner, J. H.; Zannetos, Z. S.

    1970-01-01

    Experiments on decision making in planning problems are described. Executives were tested in dealing with capital investments and competitive pricing decisions under conditions of uncertainty. A software package, the interactive risk analysis model system, was developed, and two controlled experiments were conducted. It is concluded that planning models can aid management, and predicted uses of the models are as a central tool, as an educational tool, to improve consistency in decision making, to improve communications, and as a tool for consensus decision making.

  5. Modeling of microgravity combustion experiments

    NASA Technical Reports Server (NTRS)

    Buckmaster, John

    1995-01-01

    This program started in February 1991, and is designed to improve our understanding of basic combustion phenomena by the modeling of various configurations undergoing experimental study by others. Results through 1992 were reported in the second workshop. Work since that time has examined the following topics: Flame-balls; Intrinsic and acoustic instabilities in multiphase mixtures; Radiation effects in premixed combustion; Smouldering, both forward and reverse, as well as two dimensional smoulder.

  6. The Database for Reaching Experiments and Models

    PubMed Central

    Walker, Ben; Kording, Konrad

    2013-01-01

    Reaching is one of the central experimental paradigms in the field of motor control, and many computational models of reaching have been published. While most of these models try to explain subject data (such as movement kinematics, reaching performance, forces, etc.) from only a single experiment, distinct experiments often share experimental conditions and record similar kinematics. This suggests that reaching models could be applied to (and falsified by) multiple experiments. However, using multiple datasets is difficult because experimental data formats vary widely. Standardizing data formats promises to enable scientists to test model predictions against many experiments and to compare experimental results across labs. Here we report on the development of a new resource available to scientists: a database of reaching called the Database for Reaching Experiments And Models (DREAM). DREAM collects both experimental datasets and models and facilitates their comparison by standardizing formats. The DREAM project promises to be useful for experimentalists who want to understand how their data relates to models, for modelers who want to test their theories, and for educators who want to help students better understand reaching experiments, models, and data analysis. PMID:24244351

  7. Fresh SETI Strategies

    NASA Astrophysics Data System (ADS)

    Tough, A.

    If a smart probe or some other form of extraterrestrial intelligence has reached our planet, what is the next logical step in our scientific search for it? Fresh new search strategies are required. One innovative strategy, an invitation to ETI launched in 1996, was made possible by the creation of the World Wide Web. Other fresh search strategies, too, are emerging.

  8. Modeling Choice and Valuation in Decision Experiments

    ERIC Educational Resources Information Center

    Loomes, Graham

    2010-01-01

    This article develops a parsimonious descriptive model of individual choice and valuation in the kinds of experiments that constitute a substantial part of the literature relating to decision making under risk and uncertainty. It suggests that many of the best known "regularities" observed in those experiments may arise from a tendency for…

  9. Microwave scattering models and basic experiments

    NASA Technical Reports Server (NTRS)

    Fung, Adrian K.

    1989-01-01

    Progress is summarized which has been made in four areas of study: (1) scattering model development for sparsely populated media, such as a forested area; (2) scattering model development for dense media, such as a sea ice medium or a snow covered terrain; (3) model development for randomly rough surfaces; and (4) design and conduct of basic scattering and attenuation experiments suitable for the verification of theoretical models.

  10. Using ecosystem experiments to improve vegetation models

    NASA Astrophysics Data System (ADS)

    Medlyn, Belinda E.; Zaehle, Sönke; de Kauwe, Martin G.; Walker, Anthony P.; Dietze, Michael C.; Hanson, Paul J.; Hickler, Thomas; Jain, Atul K.; Luo, Yiqi; Parton, William; Prentice, I. Colin; Thornton, Peter E.; Wang, Shusen; Wang, Ying-Ping; Weng, Ensheng; Iversen, Colleen M.; McCarthy, Heather R.; Warren, Jeffrey M.; Oren, Ram; Norby, Richard J.

    2015-06-01

    Ecosystem responses to rising CO2 concentrations are a major source of uncertainty in climate change projections. Data from ecosystem-scale Free-Air CO2 Enrichment (FACE) experiments provide a unique opportunity to reduce this uncertainty. The recent FACE Model-Data Synthesis project aimed to use the information gathered in two forest FACE experiments to assess and improve land ecosystem models. A new 'assumption-centred' model intercomparison approach was used, in which participating models were evaluated against experimental data based on the ways in which they represent key ecological processes. By identifying and evaluating the main assumptions causing differences among models, the assumption-centred approach produced a clear roadmap for reducing model uncertainty. Here, we explain this approach and summarize the resulting research agenda. We encourage the application of this approach in other model intercomparison projects to fundamentally improve predictive understanding of the Earth system.

  11. Fresh Soy Oil Protects Against Vascular Changes in an Estrogen-Deficient Rat Model: An Electron Microscopy Study

    PubMed Central

    Adam, Siti Khadijah; Das, Srijit; Othman, Faizah; Jaarin, Kamsiah

    2009-01-01

    OBJECTIVE To observe the effects of consuming repeatedly heated soy oil on the aortic tissues of estrogen-deficient rats. METHODS Thirty female Sprague Dawley rats (200–250 g) were divided equally into five groups. One group served as the normal control (NC) group. The four treated groups were ovariectomized and were fed as follows: 2% cholesterol diet (OVXC); 2% cholesterol diet + fresh soy oil (FSO); 2% cholesterol diet + once-heated soy oil (1HSO); and 2% cholesterol diet + five-times-heated soy oil (5HSO). After four months, the rats were sacrificed, and the aortic tissues were obtained for histological studies. RESULTS After four months of feeding, the NC, FSO and 1HSO groups had a lower body weight gain compared to the OVXC and 5HSO groups. The tunica intima/media ratio in the 5HSO group was significantly thicker (p < 0.05) compared to the NC, OVXC and FSO groups. Electron microscopy showed that endothelial cells were normally shaped in the FSO and NC groups but irregular in the 1HSO and 5HSO groups. A greater number of collagen fibers and vacuoles were observed in the 5HSO group compared to the other treatment groups. CONCLUSIONS Fresh soy oil offered protection in the estrogen-deficient state, as these rats had similar features to those of the NC group. The damage to the tunica intima and the increase in the ratio of tunica intima/media thickness showed the deleterious effect of consuming repeatedly heated soy oil in castrated female rats. PMID:19936186

  12. A Hadronization Model for the MINOS Experiment

    NASA Astrophysics Data System (ADS)

    Yang, T.; Andreopoulos, C.; Gallagher, H.; Kehayias, P.

    2007-12-01

    We present a detailed description of the Andreopoulos-Gallagher-Kehayias-Yang (AGKY) hadronic multiparticle production model. This model was developed within the context of the MINOS experiment [4]. Its validity spans a wide invariant mass range starting from as low as the pion production threshold. It exhibits satisfactory agreement with a wide variety of experimental data.

  13. Fresh Veggies from Space

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Professor Marc Anderson of the University of Wisconsin-Madison developed a technology for use in plant-growth experiments aboard the Space Shuttle. Anderson's research and WCSAR's technology were funded by NASA and resulted in a joint technology licensed to KES Science and Technology, Inc. This transfer of space-age technology resulted in the creation of a new plant-saving product, an ethylene scrubber for plant growth chambers. This innovation presents commercial benefits for the food industry in the form of a new device, named Bio-KES. Bio-KES removes ethylene and helps to prevent spoilage. Ethylene accounts for up to 10 percent of produce losses and 5 percent of flower losses. Using Bio-KES in storage rooms and displays will increase the shelf life of perishable foods by more than one week, drastically reducing the costs associated with discarded rotten foods and flowers. The savings could potentially be passed on to consumers. For NASA, the device means that astronauts can conduct commercial agricultural research in space. Eventually, it may also help to grow food in space and keep it fresh longer. This could lead to less packaged food being taken aboard missions since it could be cultivated in an ethylene-free environment.

  14. Argonne Bubble Experiment Thermal Model Development

    SciTech Connect

    Buechler, Cynthia Eileen

    2015-12-03

    This report will describe the Computational Fluid Dynamics (CFD) model that was developed to calculate the temperatures and gas volume fractions in the solution vessel during the irradiation. It is based on the model used to calculate temperatures and volume fractions in an annular vessel containing an aqueous solution of uranium . The experiment was repeated at several electron beam power levels, but the CFD analysis was performed only for the 12 kW irradiation, because this experiment came the closest to reaching a steady-state condition. The aim of the study is to compare results of the calculation with experimental measurements to determine the validity of the CFD model.

  15. STELLA Experiment: Design and Model Predictions

    SciTech Connect

    Kimura, W. D.; Babzien, M.; Ben-Zvi, I.; Campbell, L. P.; Cline, D. B.; Fiorito, R. B.; Gallardo, J. C.; Gottschalk, S. C.; He, P.; Kusche, K. P.; Liu, Y.; Pantell, R. H.; Pogorelsky, I. V.; Quimby, D. C.; Robinson, K. E.; Rule, D. W.; Sandweiss, J.; Skaritka, J.; van Steenbergen, A.; Steinhauer, L. C.; Yakimenko, V.

    1998-07-05

    The STaged ELectron Laser Acceleration (STELLA) experiment will be one of the first to examine the critical issue of staging the laser acceleration process. The BNL inverse free electron laser (EEL) will serve as a prebuncher to generate {approx} 1 {micro}m long microbunches. These microbunches will be accelerated by an inverse Cerenkov acceleration (ICA) stage. A comprehensive model of the STELLA experiment is described. This model includes the EEL prebunching, drift and focusing of the microbunches into the ICA stage, and their subsequent acceleration. The model predictions will be presented including the results of a system error study to determine the sensitivity to uncertainties in various system parameters.

  16. Extracting Models in Single Molecule Experiments

    NASA Astrophysics Data System (ADS)

    Presse, Steve

    2013-03-01

    Single molecule experiments can now monitor the journey of a protein from its assembly near a ribosome to its proteolytic demise. Ideally all single molecule data should be self-explanatory. However data originating from single molecule experiments is particularly challenging to interpret on account of fluctuations and noise at such small scales. Realistically, basic understanding comes from models carefully extracted from the noisy data. Statistical mechanics, and maximum entropy in particular, provide a powerful framework for accomplishing this task in a principled fashion. Here I will discuss our work in extracting conformational memory from single molecule force spectroscopy experiments on large biomolecules. One clear advantage of this method is that we let the data tend towards the correct model, we do not fit the data. I will show that the dynamical model of the single molecule dynamics which emerges from this analysis is often more textured and complex than could otherwise come from fitting the data to a pre-conceived model.

  17. Using Ecosystem Experiments to Improve Vegetation Models

    SciTech Connect

    Medlyn, Belinda; Zaehle, S; DeKauwe, Martin G.; Walker, Anthony P.; Dietze, Michael; Hanson, Paul J.; Hickler, Thomas; Jain, Atul; Luo, Yiqi; Parton, William; Prentice, I. Collin; Thornton, Peter E.; Wang, Shusen; Wang, Yingping; Weng, Ensheng; Iversen, Colleen M.; McCarthy, Heather R.; Warren, Jeffrey; Oren, Ram; Norby, Richard J

    2015-05-21

    Ecosystem responses to rising CO2 concentrations are a major source of uncertainty in climate change projections. Data from ecosystem-scale Free-Air CO2 Enrichment (FACE) experiments provide a unique opportunity to reduce this uncertainty. The recent FACE Model–Data Synthesis project aimed to use the information gathered in two forest FACE experiments to assess and improve land ecosystem models. A new 'assumption-centred' model intercomparison approach was used, in which participating models were evaluated against experimental data based on the ways in which they represent key ecological processes. Identifying and evaluating the main assumptions caused differences among models, and the assumption-centered approach produced a clear roadmap for reducing model uncertainty. We explain this approach and summarize the resulting research agenda. We encourage the application of this approach in other model intercomparison projects to fundamentally improve predictive understanding of the Earth system.

  18. Using Ecosystem Experiments to Improve Vegetation Models

    DOE PAGESBeta

    Medlyn, Belinda; Zaehle, S; DeKauwe, Martin G.; Walker, Anthony P.; Dietze, Michael; Hanson, Paul J.; Hickler, Thomas; Jain, Atul; Luo, Yiqi; Parton, William; et al

    2015-05-21

    Ecosystem responses to rising CO2 concentrations are a major source of uncertainty in climate change projections. Data from ecosystem-scale Free-Air CO2 Enrichment (FACE) experiments provide a unique opportunity to reduce this uncertainty. The recent FACE Model–Data Synthesis project aimed to use the information gathered in two forest FACE experiments to assess and improve land ecosystem models. A new 'assumption-centred' model intercomparison approach was used, in which participating models were evaluated against experimental data based on the ways in which they represent key ecological processes. Identifying and evaluating the main assumptions caused differences among models, and the assumption-centered approach produced amore » clear roadmap for reducing model uncertainty. We explain this approach and summarize the resulting research agenda. We encourage the application of this approach in other model intercomparison projects to fundamentally improve predictive understanding of the Earth system.« less

  19. Experiences with two-equation turbulence models

    NASA Technical Reports Server (NTRS)

    Singhal, Ashok K.; Lai, Yong G.; Avva, Ram K.

    1995-01-01

    This viewgraph presentation discusses the following: introduction to CFD Research Corporation; experiences with two-equation models - models used, numerical difficulties, validation and applications, and strengths and weaknesses; and answers to three questions posed by the workshop organizing committee - what are your customers telling you, what are you doing in-house, and how can NASA-CMOTT (Center for Modeling of Turbulence and Transition) help.

  20. Quantification of the binding potential of cell-surface receptors in fresh excised specimens via dual-probe modeling of SERS nanoparticles

    PubMed Central

    Sinha, Lagnojita; Wang, Yu; Yang, Cynthia; Khan, Altaz; Brankov, Jovan G.; Liu, Jonathan T. C.; Tichauer, Kenneth M.

    2015-01-01

    The complete removal of cancerous tissue is a central aim of surgical oncology, but is difficult to achieve in certain cases, especially when the removal of surrounding normal tissues must be minimized. Therefore, when post-operative pathology identifies residual tumor at the surgical margins, re-excision surgeries are often necessary. An intraoperative approach for tumor-margin assessment, insensitive to nonspecific sources of molecular probe accumulation and contrast, is presented employing kinetic-modeling analysis of dual-probe staining using surface-enhanced Raman scattering nanoparticles (SERS NPs). Human glioma (U251) and epidermoid (A431) tumors were implanted subcutaneously in six athymic mice. Fresh resected tissues were stained with an equimolar mixture of epidermal growth factor receptor (EGFR)-targeted and untargeted SERS NPs. The binding potential (BP; proportional to receptor concentration) of EGFR – a cell-surface receptor associated with cancer – was estimated from kinetic modeling of targeted and untargeted NP concentrations in response to serial rinsing. EGFR BPs in healthy, U251, and A431 tissues were 0.06 ± 0.14, 1.13 ± 0.40, and 2.23 ± 0.86, respectively, which agree with flow-cytometry measurements and published reports. The ability of this approach to quantify the BP of cell-surface biomarkers in fresh tissues opens up an accurate new approach to analyze tumor margins intraoperatively. PMID:25716578

  1. Fresh Water Life.

    ERIC Educational Resources Information Center

    Kestler, Carol Susan

    1991-01-01

    Describes methodology for a fresh water life study with elementary through college age students with suggestions for proper equipment, useful guides, and other materials. Proposes an activity for the collection and study of plankton. Includes background information.(MCO)

  2. What determines fresh fish consumption in Croatia?

    PubMed

    Tomić, Marina; Matulić, Daniel; Jelić, Margareta

    2016-11-01

    Although fresh fish is widely available, consumption still remains below the recommended intake levels among the majority of European consumers. The economic crisis affects consumer food behaviour, therefore fresh fish is perceived as healthy but expensive food product. The aim of this study was to determine the factors influencing fresh fish consumption using an expanded Theory of Planned Behaviour (Ajzen, 1991) as a theoretical framework. The survey was conducted on a heterogeneous sample of 1151 Croatian fresh fish consumers. The study investigated the relationship between attitudes, perceived behavioural control, subjective norm, moral obligation, involvement in health, availability, intention and consumption of fresh fish. Structural Equation Modeling by Partial Least Squares was used to analyse the collected data. The results indicated that attitudes are the strongest positive predictor of the intention to consume fresh fish. Other significant predictors of the intention to consume fresh fish were perceived behavioural control, subjective norm, health involvement and moral obligation. The intention to consume fresh fish showed a strong positive correlation with behaviour. This survey provides valuable information for food marketing professionals and for the food industry in general. PMID:26721719

  3. Irradiation of Fresh and Fresh-Cut Fruits and Vegetables

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Consumption of fresh and fresh-cut fruits and vegetables in the USA has increased every year in the last decade. Unfortunately, the increasing consumption of fresh produce has been accompanied with an increase in the number of outbreaks and recalls due to contamination with human pathogens. Fresh f...

  4. Data production models for the CDF experiment

    SciTech Connect

    Antos, J.; Babik, M.; Benjamin, D.; Cabrera, S.; Chan, A.W.; Chen, Y.C.; Coca, M.; Cooper, B.; Genser, K.; Hatakeyama, K.; Hou, S.; Hsieh, T.L.; Jayatilaka, B.; Kraan, A.C.; Lysak, R.; Mandrichenko, I.V.; Robson, A.; Siket, M.; Stelzer, B.; Syu, J.; Teng, P.K.; /Kosice, IEF /Duke U. /Taiwan, Inst. Phys. /University Coll. London /Fermilab /Rockefeller U. /Michigan U. /Pennsylvania U. /Glasgow U. /UCLA /Tsukuba U. /New Mexico U.

    2006-06-01

    The data production for the CDF experiment is conducted on a large Linux PC farm designed to meet the needs of data collection at a maximum rate of 40 MByte/sec. We present two data production models that exploits advances in computing and communication technology. The first production farm is a centralized system that has achieved a stable data processing rate of approximately 2 TByte per day. The recently upgraded farm is migrated to the SAM (Sequential Access to data via Metadata) data handling system. The software and hardware of the CDF production farms has been successful in providing large computing and data throughput capacity to the experiment.

  5. Model-scale sound propagation experiment

    NASA Technical Reports Server (NTRS)

    Willshire, William L., Jr.

    1988-01-01

    The results of a scale model propagation experiment to investigate grazing propagation above a finite impedance boundary are reported. In the experiment, a 20 x 25 ft ground plane was installed in an anechoic chamber. Propagation tests were performed over the plywood surface of the ground plane and with the ground plane covered with felt, styrofoam, and fiberboard. Tests were performed with discrete tones in the frequency range of 10 to 15 kHz. The acoustic source and microphones varied in height above the test surface from flush to 6 in. Microphones were located in a linear array up to 18 ft from the source. A preliminary experiment using the same ground plane, but only testing the plywood and felt surfaces was performed. The results of this first experiment were encouraging, but data variability and repeatability were poor, particularly, for the felt surface, making comparisons with theoretical predictions difficult. In the main experiment the sound source, microphones, microphone positioning, data acquisition, quality of the anechoic chamber, and environmental control of the anechoic chamber were improved. High-quality, repeatable acoustic data were measured in the main experiment for all four test surfaces. Comparisons with predictions are good, but limited by uncertainties of the impedance values of the test surfaces.

  6. Modeling Hemispheric Detonation Experiments in 2-Dimensions

    SciTech Connect

    Howard, W M; Fried, L E; Vitello, P A; Druce, R L; Phillips, D; Lee, R; Mudge, S; Roeske, F

    2006-06-22

    Experiments have been performed with LX-17 (92.5% TATB and 7.5% Kel-F 800 binder) to study scaling of detonation waves using a dimensional scaling in a hemispherical divergent geometry. We model these experiments using an arbitrary Lagrange-Eulerian (ALE3D) hydrodynamics code, with reactive flow models based on the thermo-chemical code, Cheetah. The thermo-chemical code Cheetah provides a pressure-dependent kinetic rate law, along with an equation of state based on exponential-6 fluid potentials for individual detonation product species, calibrated to high pressures ({approx} few Mbars) and high temperatures (20000K). The parameters for these potentials are fit to a wide variety of experimental data, including shock, compression and sound speed data. For the un-reacted high explosive equation of state we use a modified Murnaghan form. We model the detonator (including the flyer plate) and initiation system in detail. The detonator is composed of LX-16, for which we use a program burn model. Steinberg-Guinan models5 are used for the metal components of the detonator. The booster and high explosive are LX-10 and LX-17, respectively. For both the LX-10 and LX-17, we use a pressure dependent rate law, coupled with a chemical equilibrium equation of state based on Cheetah. For LX-17, the kinetic model includes carbon clustering on the nanometer size scale.

  7. Decadal predictability of extreme fresh water export events from the Arctic Ocean into the Nordic Seas and subpolar North Atlantic

    NASA Astrophysics Data System (ADS)

    Schmith, Torben; Olsen, Steffen M.; Ringgaard, Ida M.; May, Wilhelm

    2016-04-01

    Abrupt fresh water releases originating in the Arctic Ocean have been documented to affect ocean circulation and climate in the North Atlantic area. Therefore, in this study, we investigate prospects for predicting such events up to one decade ahead. This is done in a perfect model setup by a combination of analyzing a 500 year control experiment and dedicated ensemble experiment aimed at predicting selected 10 year long segments of the control experiment. The selected segments are characterized by a large positive or negative trend in the total fresh water content in the Arctic Ocean. The analysis of the components (liquid fresh water and sea ice) reveals that they develop in a near random walk manner. From this we conclude that the main mechanism is integration of fresh water in the Beaufort Gyre through Ekman pumping from the randomly varying atmosphere. Therefore, the predictions from the ensemble experiments are on average not better than a damped persistence predictions. By running two different families of ensemble predictions, one starting from the 'observed' ocean globally, and one starting from climatology in the Arctic Ocean and from the observed ocean elsewhere, we conclude that the former outperforms the latter for the first few years as regards liquid fresh water and for the first year as regards sea ice. Analysis of the model experiments in terms of the fresh water export from the Arctic Ocean into Nordic seas and the subpolar North Atlantic reveals a very modest potential for predictability.

  8. Application of non-linear models to predict inhibition effects of various plant hydrosols on Listeria monocytogenes inoculated on fresh-cut apples.

    PubMed

    Ozturk, Ismet; Tornuk, Fatih; Sagdic, Osman; Kisi, Ozgur

    2012-07-01

    In this study, we studied the effects of some plant hydrosols obtained from bay leaf, black cumin, rosemary, sage, and thyme in reducing Listeria monocytogenes on the surface of fresh-cut apple cubes. Adaptive neuro-fuzzy inference system (ANFIS), artificial neural network (ANN), and multiple linear regression (MLR) models were used for describing the behavior of L. monocytogenes against the hydrosol treatments. Approximately 1-1.5 log CFU/g decreases in L. monocytogenes counts were observed after individual hydrosol treatments for 20 min. By extending the treatment time to 60 min, thyme, sage, or rosemary hydrosols eliminated L. monocytogenes, whereas black cumin and bay leaf hydrosols did not lead to additional reductions. In addition to antibacterial measurements, the abilities of ANFIS, ANN, and MLR models were compared with respect to estimation of the survival of L. monocytogenes. The root mean square error, mean absolute error, and determination coefficient statistics were used as comparison criteria. The comparison results indicated that the ANFIS model performed the best for estimating the effects of the plant hydrosols on L. monocytogenes counts. The ANN model was also effective; the MLR model was found to be poor at estimating L. monocytogenes numbers. PMID:22690764

  9. Conceptualization of a fresh groundwater lens influenced by climate change: A modeling study of an arid-region island in the Persian Gulf, Iran

    NASA Astrophysics Data System (ADS)

    Mahmoodzadeh, Davood; Ketabchi, Hamed; Ataie-Ashtiani, Behzad; Simmons, Craig T.

    2014-11-01

    Understanding the fresh groundwater lens (FGL) behavior and potential threat of climatic-induced seawater intrusion (SWI) are significant for the future water resources management of many small islands. In this paper, the FGL of Kish Island, an arid-region case in the Persian Gulf, Iran, is modeled using two-dimensional (2D) and three-dimensional (3D) simulations. These simulations are based on the application of SUTRA, a density-dependent groundwater numerical model. Also, the numerical model parameters are calibrated using PEST, an automated parameter estimation code. Firstly a detailed conceptualization of the FGL model is completed to understand the sensitivity of the FGL to some particular aspects of the model prior to analysis of climate change simulations. For these investigations, the FGL system is defined based on Kish Island system to accomplish the integrated comparison of features of a conceptual model that are representative of real-world systems. This is the first study which adopts such an approach. The comparison of cross-sectional simulations suggests that the two-layer properties of the Kish Island aquifer have a significant influence on the FGL while the impacts of lateral-boundary irregularities are negligible. The impacts of sea-level rise (SLR), associated land-surface inundation (LSI), and variations in recharge rate on the FGL salinization of Kish Island are investigated numerically. Variations of SLR value (1-4 m) and net recharge rate (17-24 mm/year) are considered to cover a possible range of climatic scenarios in this arid-region island. The 2D and 3D simulation results demonstrate that LSI caused by SLR and recharge rate variation impacts are more important factors in the FGL in comparison to estimated SLR impacts without LSI. It is also shown that climate change impacts on the FGL are long-term to reach a new FGL equilibrium in the case of Kish Island's aquifer system. The comparative analysis of 2D and 3D results shows that three

  10. Background modeling for the GERDA experiment

    NASA Astrophysics Data System (ADS)

    Becerici-Schmidt, N.; Gerda Collaboration

    2013-08-01

    The neutrinoless double beta (0νββ) decay experiment GERDA at the LNGS of INFN has started physics data taking in November 2011. This paper presents an analysis aimed at understanding and modeling the observed background energy spectrum, which plays an essential role in searches for a rare signal like 0νββ decay. A very promising preliminary model has been obtained, with the systematic uncertainties still under study. Important information can be deduced from the model such as the expected background and its decomposition in the signal region. According to the model the main background contributions around Qββ come from 214Bi, 228Th, 42K, 60Co and α emitting isotopes in the 226Ra decay chain, with a fraction depending on the assumed source positions.

  11. Background modeling for the GERDA experiment

    SciTech Connect

    Becerici-Schmidt, N.; Collaboration: GERDA Collaboration

    2013-08-08

    The neutrinoless double beta (0νββ) decay experiment GERDA at the LNGS of INFN has started physics data taking in November 2011. This paper presents an analysis aimed at understanding and modeling the observed background energy spectrum, which plays an essential role in searches for a rare signal like 0νββ decay. A very promising preliminary model has been obtained, with the systematic uncertainties still under study. Important information can be deduced from the model such as the expected background and its decomposition in the signal region. According to the model the main background contributions around Q{sub ββ} come from {sup 214}Bi, {sup 228}Th, {sup 42}K, {sup 60}Co and α emitting isotopes in the {sup 226}Ra decay chain, with a fraction depending on the assumed source positions.

  12. Impact polymorphs of quartz: experiments and modelling

    NASA Astrophysics Data System (ADS)

    Price, M. C.; Dutta, R.; Burchell, M. J.; Cole, M. J.

    2013-09-01

    We have used the light gas gun at the University of Kent to perform a series of impact experiments firing quartz projectiles onto metal, quartz and sapphire targets. The aim is to quantify the amount of any high pressure quartz polymorphs produced, and use these data to develop our hydrocode modelling to enable the predict ion of the quantity of polymorphs produced during a planetary scale impact.

  13. Data assimilation and model evaluation experiment datasets

    NASA Technical Reports Server (NTRS)

    Lai, Chung-Cheng A.; Qian, Wen; Glenn, Scott M.

    1994-01-01

    The Institute for Naval Oceanography, in cooperation with Naval Research Laboratories and universities, executed the Data Assimilation and Model Evaluation Experiment (DAMEE) for the Gulf Stream region during fiscal years 1991-1993. Enormous effort has gone into the preparation of several high-quality and consistent datasets for model initialization and verification. This paper describes the preparation process, the temporal and spatial scopes, the contents, the structure, etc., of these datasets. The goal of DAMEE and the need of data for the four phases of experiment are briefly stated. The preparation of DAMEE datasets consisted of a series of processes: (1) collection of observational data; (2) analysis and interpretation; (3) interpolation using the Optimum Thermal Interpolation System package; (4) quality control and re-analysis; and (5) data archiving and software documentation. The data products from these processes included a time series of 3D fields of temperature and salinity, 2D fields of surface dynamic height and mixed-layer depth, analysis of the Gulf Stream and rings system, and bathythermograph profiles. To date, these are the most detailed and high-quality data for mesoscale ocean modeling, data assimilation, and forecasting research. Feedback from ocean modeling groups who tested this data was incorporated into its refinement. Suggestions for DAMEE data usages include (1) ocean modeling and data assimilation studies, (2) diagnosis and theoretical studies, and (3) comparisons with locally detailed observations.

  14. Shop Around for Freshness.

    ERIC Educational Resources Information Center

    Evans, George P.

    1998-01-01

    Argues that cliches make writing stale and flat, and that getting rid of them is a necessity. Lists the "top 14" cliches gathered by a Columbia Scholastic Press Association judge. Uses examples to show how cleansing a passage of its superlatives and cliches improves the writing, adding clarity, fairness, and objectivity as well as freshness and…

  15. Microbial Successions Are Associated with Changes in Chemical Profiles of a Model Refrigerated Fresh Pork Sausage during an 80-Day Shelf Life Study

    PubMed Central

    David, Jairus R. D.; Gilbreth, Stefanie Evans; Smith, Gordon; Nietfeldt, Joseph; Legge, Ryan; Kim, Jaehyoung; Sinha, Rohita; Duncan, Christopher E.; Ma, Junjie; Singh, Indarpal

    2014-01-01

    Fresh pork sausage is produced without a microbial kill step and therefore chilled or frozen to control microbial growth. In this report, the microbiota in a chilled fresh pork sausage model produced with or without an antimicrobial combination of sodium lactate and sodium diacetate was studied using a combination of traditional microbiological methods and deep pyrosequencing of 16S rRNA gene amplicons. In the untreated system, microbial populations rose from 102 to 106 CFU/g within 15 days of storage at 4°C, peaking at nearly 108 CFU/g by day 30. Pyrosequencing revealed a complex community at day 0, with taxa belonging to the Bacilli, Gammaproteobacteria, Betaproteobacteria, Actinobacteria, Bacteroidetes, and Clostridia. During storage at 4°C, the untreated system displayed a complex succession, with species of Weissella and Leuconostoc that dominate the product at day 0 being displaced by species of Pseudomonas (P. lini and P. psychrophila) within 15 days. By day 30, a second wave of taxa (Lactobacillus graminis, Carnobacterium divergens, Buttiauxella brennerae, Yersinia mollaretti, and a taxon of Serratia) dominated the population, and this succession coincided with significant chemical changes in the matrix. Treatment with lactate-diacetate altered the dynamics dramatically, yielding a monophasic growth curve of a single species of Lactobacillus (L. graminis), followed by a uniform selective die-off of the majority of species in the population. Of the six species of Lactobacillus that were routinely detected, L. graminis became the dominant member in all samples, and its origins were traced to the spice blend used in the formulation. PMID:24928886

  16. Microbial successions are associated with changes in chemical profiles of a model refrigerated fresh pork sausage during an 80-day shelf life study.

    PubMed

    Benson, Andrew K; David, Jairus R D; Gilbreth, Stefanie Evans; Smith, Gordon; Nietfeldt, Joseph; Legge, Ryan; Kim, Jaehyoung; Sinha, Rohita; Duncan, Christopher E; Ma, Junjie; Singh, Indarpal

    2014-09-01

    Fresh pork sausage is produced without a microbial kill step and therefore chilled or frozen to control microbial growth. In this report, the microbiota in a chilled fresh pork sausage model produced with or without an antimicrobial combination of sodium lactate and sodium diacetate was studied using a combination of traditional microbiological methods and deep pyrosequencing of 16S rRNA gene amplicons. In the untreated system, microbial populations rose from 10(2) to 10(6) CFU/g within 15 days of storage at 4°C, peaking at nearly 10(8) CFU/g by day 30. Pyrosequencing revealed a complex community at day 0, with taxa belonging to the Bacilli, Gammaproteobacteria, Betaproteobacteria, Actinobacteria, Bacteroidetes, and Clostridia. During storage at 4°C, the untreated system displayed a complex succession, with species of Weissella and Leuconostoc that dominate the product at day 0 being displaced by species of Pseudomonas (P. lini and P. psychrophila) within 15 days. By day 30, a second wave of taxa (Lactobacillus graminis, Carnobacterium divergens, Buttiauxella brennerae, Yersinia mollaretti, and a taxon of Serratia) dominated the population, and this succession coincided with significant chemical changes in the matrix. Treatment with lactate-diacetate altered the dynamics dramatically, yielding a monophasic growth curve of a single species of Lactobacillus (L. graminis), followed by a uniform selective die-off of the majority of species in the population. Of the six species of Lactobacillus that were routinely detected, L. graminis became the dominant member in all samples, and its origins were traced to the spice blend used in the formulation. PMID:24928886

  17. Predictive modeling for growth of non- and cold-adapted Listeria Monocytogenes on fresh-cut cantaloupe at different storage temperatures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aim of this study was to determine the growth kinetics of Listeria monocytogenes, with and without cold-adaption, on fresh-cut cantaloupe under different storage temperatures. Fresh-cut samples, spot inoculated with a four-strain cocktail of L. monocytogenes (about 3.2 log CFU/g), were exposed t...

  18. Observation simulation experiments with regional prediction models

    NASA Technical Reports Server (NTRS)

    Diak, George; Perkey, Donald J.; Kalb, Michael; Robertson, Franklin R.; Jedlovec, Gary

    1990-01-01

    Research efforts in FY 1990 included studies employing regional scale numerical models as aids in evaluating potential contributions of specific satellite observing systems (current and future) to numerical prediction. One study involves Observing System Simulation Experiments (OSSEs) which mimic operational initialization/forecast cycles but incorporate simulated Advanced Microwave Sounding Unit (AMSU) radiances as input data. The objective of this and related studies is to anticipate the potential value of data from these satellite systems, and develop applications of remotely sensed data for the benefit of short range forecasts. Techniques are also being used that rely on numerical model-based synthetic satellite radiances to interpret the information content of various types of remotely sensed image and sounding products. With this approach, evolution of simulated channel radiance image features can be directly interpreted in terms of the atmospheric dynamical processes depicted by a model. Progress is being made in a study using the internal consistency of a regional prediction model to simplify the assessment of forced diabatic heating and moisture initialization in reducing model spinup times. Techniques for model initialization are being examined, with focus on implications for potential applications of remote microwave observations, including AMSU and Special Sensor Microwave Imager (SSM/I), in shortening model spinup time for regional prediction.

  19. Experiences in evaluating regional air quality models

    NASA Astrophysics Data System (ADS)

    Liu, Mei-Kao; Greenfield, Stanley M.

    Any area of the world concerned with the health and welfare of its people and the viability of its ecological system must eventually address the question of the control of air pollution. This is true in developed countries as well as countries that are undergoing a considerable degree of industrialization. The control or limitation of the emissions of a pollutant can be very costly. To avoid ineffective or unnecessary control, the nature of the problem must be fully understood and the relationship between source emissions and ambient concentrations must be established. Mathematical models, while admittedly containing large uncertainties, can be used to examine alternatives of emission restrictions for achieving safe ambient concentrations. The focus of this paper is to summarize our experiences with modeling regional air quality in the United States and Western Europe. The following modeling experiences have been used: future SO 2 and sulfate distributions and projected acidic deposition as related to coal development in the northern Great Plains in the U.S.; analysis of regional ozone and sulfate episodes in the northeastern U.S.; analysis of the regional ozone problem in western Europe in support of alternative emission control strategies; analysis of distributions of toxic chemicals in the Southeast Ohio River Valley in support of the design of a monitoring network human exposure. Collectively, these prior modeling analyses can be invaluable in examining a similar problem in other parts of the world as well, such as the Pacific rim in Asia.

  20. Ballistic Response of Fabrics: Model and Experiments

    NASA Astrophysics Data System (ADS)

    Orphal, Dennis L.; Walker Anderson, James D., Jr.

    2001-06-01

    Walker (1999)developed an analytical model for the dynamic response of fabrics to ballistic impact. From this model the force, F, applied to the projectile by the fabric is derived to be F = 8/9 (ET*)h^3/R^2, where E is the Young's modulus of the fabric, T* is the "effective thickness" of the fabric and equal to the ratio of the areal density of the fabric to the fiber density, h is the displacement of the fabric on the axis of impact and R is the radius of the fabric deformation or "bulge". Ballistic tests against Zylon^TM fabric have been performed to measure h and R as a function of time. The results of these experiments are presented and analyzed in the context of the Walker model. Walker (1999), Proceedings of the 18th International Symposium on Ballistics, pp. 1231.

  1. Process modelling for Space Station experiments

    NASA Technical Reports Server (NTRS)

    Alexander, J. Iwan D.; Rosenberger, Franz; Nadarajah, Arunan; Ouazzani, Jalil; Amiroudine, Sakir

    1990-01-01

    Examined here is the sensitivity of a variety of space experiments to residual accelerations. In all the cases discussed the sensitivity is related to the dynamic response of a fluid. In some cases the sensitivity can be defined by the magnitude of the response of the velocity field. This response may involve motion of the fluid associated with internal density gradients, or the motion of a free liquid surface. For fluids with internal density gradients, the type of acceleration to which the experiment is sensitive will depend on whether buoyancy driven convection must be small in comparison to other types of fluid motion, or fluid motion must be suppressed or eliminated. In the latter case, the experiments are sensitive to steady and low frequency accelerations. For experiments such as the directional solidification of melts with two or more components, determination of the velocity response alone is insufficient to assess the sensitivity. The effect of the velocity on the composition and temperature field must be considered, particularly in the vicinity of the melt-crystal interface. As far as the response to transient disturbances is concerned, the sensitivity is determined by both the magnitude and frequency of the acceleration and the characteristic momentum and solute diffusion times. The microgravity environment, a numerical analysis of low gravity tolerance of the Bridgman-Stockbarger technique, and modeling crystal growth by physical vapor transport in closed ampoules are discussed.

  2. Fresh embryo donation for human embryonic stem cell (hESC) research: the experiences and values of IVF couples asked to be embryo donors

    PubMed Central

    Haimes, E.; Taylor, K.

    2009-01-01

    BACKGROUND This article reports on an investigation of the views of IVF couples asked to donate fresh embryos for research and contributes to the debates on: the acceptability of human embryonic stem cell (hESC) research, the moral status of the human embryo and embryo donation for research. METHODS A hypothesis-generating design was followed. All IVF couples in one UK clinic who were asked to donate embryos in 1 year were contacted 6 weeks after their pregnancy result. Forty four in-depth interviews were conducted. RESULTS Interviewees were preoccupied with IVF treatment and the request to donate was a secondary consideration. They used a complex and dynamic system of embryo classification. Initially, all embryos were important but then their focus shifted to those that had most potential to produce a baby. At that point, ‘other’ embryos were less important though they later realise that they did not know what happened to them. Guessing that these embryos went to research, interviewees preferred not to contemplate what that might entail. The embryos that caused interviewees most concern were good quality embryos that might have produced a baby but went to research instead. ‘The’ embryo, the morally laden, but abstract, entity, did not play a central role in their decision-making. CONCLUSIONS This study, despite missing those who refuse to donate embryos, suggests that debates on embryo donation for hESC research should include the views of embryo donors and should consider the social, as well as the moral, status of the human embryo. PMID:19502616

  3. Magnitudes and sources of dissolved inorganic phosphorus inputs to surface fresh waters and the coastal zone: A new global model

    NASA Astrophysics Data System (ADS)

    Harrison, John A.; Bouwman, A. F.; Mayorga, Emilio; Seitzinger, Sybil

    2010-03-01

    As a limiting nutrient in aquatic systems, phosphorus (P) plays an important role in controlling freshwater and coastal primary productivity and ecosystem dynamics, increasing frequency and severity of harmful and nuisance algae blooms and hypoxia, as well as contributing to loss of biodiversity. Although dissolved inorganic P (DIP) often constitutes a relatively small fraction of the total P pool in aquatic systems, its bioavailability makes it an important determinant of ecosystem function. Here we describe, apply, evaluate, and interpret an enhanced version of the Global Nutrient Export from Watersheds (NEWS)-DIP model: NEWS-DIP-Half Degree (NEWS-DIP-HD). Improvements to NEWS-DIP-HD over the original NEWS DIP model include (1) the preservation of spatial resolution of input data sets at the 0.5 degree level and (2) explicit downstream routing of water and DIP from half-degree cell to half-degree cell using a global flow-direction representation. NEWS-DIP explains 78% and 62% of the variability in per-basin DIP export (DIP load) for U.S. Geological Survey (USGS) and global stations, respectively, similar to the original NEWS-DIP model and somewhat more than other global models of DIP loading and export. NEWS-DIP-HD output suggests that hot spots for DIP loading tend to occur in urban centers, with the highest per-area rate of DIP loading predicted for the half-degree grid cell containing Tokyo (6366 kg P km-2 yr-1). Furthermore, cities with populations >100,000 accounted for 35% of global surface water DIP loading while covering less than 2% of global land surface area. NEWS-DIP-HD also indicates that humans supply more DIP to surface waters than natural weathering over the majority (53%) of the Earth's land surface, with a much larger area dominated by DIP point sources than nonpoint sources (52% versus 1% of the global land surface, respectively). NEWS-DIP-HD also suggests that while humans had increased DIP input to surface waters more than fourfold globally

  4. Experience with the CMS Event Data Model

    SciTech Connect

    Elmer, P.; Hegner, B.; Sexton-Kennedy, L.; /Fermilab

    2009-06-01

    The re-engineered CMS EDM was presented at CHEP in 2006. Since that time we have gained a lot of operational experience with the chosen model. We will present some of our findings, and attempt to evaluate how well it is meeting its goals. We will discuss some of the new features that have been added since 2006 as well as some of the problems that have been addressed. Also discussed is the level of adoption throughout CMS, which spans the trigger farm up to the final physics analysis. Future plans, in particular dealing with schema evolution and scaling, will be discussed briefly.

  5. Experiments for foam model development and validation.

    SciTech Connect

    Bourdon, Christopher Jay; Cote, Raymond O.; Moffat, Harry K.; Grillet, Anne Mary; Mahoney, James F.; Russick, Edward Mark; Adolf, Douglas Brian; Rao, Rekha Ranjana; Thompson, Kyle Richard; Kraynik, Andrew Michael; Castaneda, Jaime N.; Brotherton, Christopher M.; Mondy, Lisa Ann; Gorby, Allen D.

    2008-09-01

    A series of experiments has been performed to allow observation of the foaming process and the collection of temperature, rise rate, and microstructural data. Microfocus video is used in conjunction with particle image velocimetry (PIV) to elucidate the boundary condition at the wall. Rheology, reaction kinetics and density measurements complement the flow visualization. X-ray computed tomography (CT) is used to examine the cured foams to determine density gradients. These data provide input to a continuum level finite element model of the blowing process.

  6. Multiaxial behavior of foams - Experiments and modeling

    NASA Astrophysics Data System (ADS)

    Maheo, Laurent; Guérard, Sandra; Rio, Gérard; Donnard, Adrien; Viot, Philippe

    2015-09-01

    Cellular materials are strongly related to pressure level inside the material. It is therefore important to use experiments which can highlight (i) the pressure-volume behavior, (ii) the shear-shape behavior for different pressure level. Authors propose to use hydrostatic compressive, shear and combined pressure-shear tests to determine cellular materials behavior. Finite Element Modeling must take into account these behavior specificities. Authors chose to use a behavior law with a Hyperelastic, a Viscous and a Hysteretic contributions. Specific developments has been performed on the Hyperelastic one by separating the spherical and the deviatoric part to take into account volume change and shape change characteristics of cellular materials.

  7. Modelling the optical properties of fresh biomass burning aerosol produced in a smoke chamber: results from the EFEU campaign

    NASA Astrophysics Data System (ADS)

    Hungershoefer, K.; Zeromskiene, K.; Iinuma, Y.; Helas, G.; Trentmann, J.; Trautmann, T.; Parmar, R. S.; Wiedensohler, A.; Andreae, M. O.; Schmid, O.

    2008-07-01

    A better characterisation of the optical properties of biomass burning aerosol as a function of the burning conditions is required in order to quantify their effects on climate and atmospheric chemistry. Controlled laboratory combustion experiments with different fuel types were carried out at the combustion facility of the Max Planck Institute for Chemistry (Mainz, Germany) as part of the "Impact of Vegetation Fires on the Composition and Circulation of the Atmosphere" (EFEU) project. The combustion conditions were monitored with concomitant CO2 and CO measurements. The mass scattering efficiencies of 8.9±0.2 m2 g-1 and 9.3±0.3 m2 g-1 obtained for aerosol particles from the combustion of savanna grass and an African hardwood (musasa), respectively, are larger than typically reported mainly due to differences in particle size distribution. The photoacoustically measured mass absorption efficiencies of 0.51±0.02 m2 g-1 and 0.50±0.02 m2 g-1 were at the lower end of the literature values. Using the measured size distributions as well as the mass scattering and absorption efficiencies, Mie calculations provided effective refractive indices of 1.60-0.010i (savanna grass) and 1.56-0.010i (musasa) (λ=0.55 μm). The apparent discrepancy between the low imaginary part of the refractive index and the high apparent elemental carbon (ECa) fractions (8 to 15%) obtained from the thermographic analysis of impactor samples can be explained by a positive bias in the elemental carbon data due to the presence of high molecular weight organic substances. Potential artefacts in optical properties due to instrument bias, non-natural burning conditions and unrealistic dilution history of the laboratory smoke cannot be ruled out and are also discussed in this study.

  8. Phytoavailability of thallium - A model soil experiment

    NASA Astrophysics Data System (ADS)

    Vanek, Ales; Mihaljevic, Martin; Galuskova, Ivana; Komarek, Michael

    2013-04-01

    The study deals with the environmental stability of Tl-modified phases (ferrihydrite, goethite, birnessite, calcite and illite) and phytoavailability of Tl in synthetically prepared soils used in a model vegetation experiment. The obtained data clearly demonstrate a strong relationship between the mineralogical position of Tl in the model soil and its uptake by the plant (Sinapis alba L.). The maximum rate of Tl uptake was observed for plants grown on soil containing Tl-modified illite. In contrast, soil enriched in Ksat-birnessite had the lowest potential for Tl release and phytoaccumulation. Root-induced dissolution of synthetic calcite and ferrihydrite in the rhizosphere followed by Tl mobilization was detected. Highly crystalline goethite was more stable in the rhizosphere, compared to ferrihydrite, leading to reduced biological uptake of Tl. Based on the results, the mineralogical aspect must be taken into account prior to general environmental recommendations in areas affected by Tl.

  9. Developing a Model using High School Students for Restoring, Monitoring and Conducting Research in Fresh Water Wetlands

    NASA Astrophysics Data System (ADS)

    Blueford, J. R.

    2010-12-01

    Tule Ponds at Tyson Lagoon in eastern San Francisco Bay is one of the largest sag ponds created by the Hayward Fault that has not been destroyed by urbanization. In the 1990’s Alameda County Flood Control and Water Conservation District designed a constructed wetland to naturally filter stormwater before it entered Tyson Lagoon on its way to the San Francisco Bay. The Math Science Nucleus, a non profit organization, manages the facility that incorporates high school students through community service, service learning, and research. Students do a variety of tasks from landscaping to scientific monitoring. Through contracts and grants, we create different levels of competency that the students can participate. Engineers and scientists from the two agencies involved, create tasks that are needed to be complete for successful restoration. Every year the students work on different components of restoration. A group of select student interns (usually juniors and seniors) collects and records the data during the year. Some of these students are part of a paid internship to insure their regular attendance. Every year the students compile and discuss with scientists from the Math Science Nucleus what the data set might mean and how problems can be improved. The data collected helps determine other longer term projects. This presentation will go over the journey of the last 10 years to this very successful program and will outline the steps necessary to maintain a restoration project. It will also outline the different groups that do larger projects (scouts) and liaisons with schools that allow teachers to assign projects at our facility. The validity of the data obtained by students and how we standardize our data collection from soil analysis, water chemistry, monitoring faults, and biological observations will be discussed. This joint agency model of cooperation to provide high school students with a real research opportunity has benefits that allow the program to

  10. Estimation of Fresh Water and Salt Transports in the Northern Indian Ocean Using Aquarius and Model Simulations

    NASA Astrophysics Data System (ADS)

    D'Addezio, J. M.; Bulusu, S.; Murty, V. S. N.; Nyadjro, E. S.

    2014-12-01

    The Northern Indian Ocean presents a unique dipolar Sea Surface Salinity (SSS) structure with the salty Arabian Sea (AS) on the west and the fresher Bay of Bengal (BoB) on the east. By using a combination of observational data, reanalyses, and model studies, the salinity structure of this dichotomous yet interconnected region is quantified. At the surface, the largest driver of salinity interseasonal variability is caused by the monsoonal winds and their ability to transport volume between the two water masses. Time-depth profiles reveal a rich vertical salinity profile. The AS presents with a mild salinity inversion, with salty waters above fresher ones for the majority of each annual cycle. This vertical gradient is approximately 1 psu between the surface and 200m depth. In the BoB the opposite occurs, where larger volumes of precipitation and river runoff create a lens of freshwater from the surface to approximately 50m depth year around. Salt and freshwater fluxes at the surface show a strong zonal component between the two basins along Sri Lanka twice a year. Within the basins, meridional fluxes dominate especially along the coastal regions where the EICC and WICC flow. Meridional depth-integrated salt, freshwater, and volume transports along a slice of each basin at 6°N reveal the approximate time its takes for each basin to return to equilibrium after strong transports during each monsoonal seasons advect salt and/or freshwater into or out of each respective region.

  11. Reactive transport modeling to quantify trace element release into fresh groundwater in case of CO2 leak from deep geological storage.

    NASA Astrophysics Data System (ADS)

    Lions, J.; Jakymiw, C.; Devau, N.; Barsotti, V.; Humez, P.

    2014-12-01

    Geological storage of CO2 in deep saline aquifers is one of the options considered for the mitigation of CO2 emissions into the atmosphere. A deep geological CO2 storage is not expected to leak but potential impacts on groundwater have to be studied. A better understanding on how it could affect groundwater quality, aquifer minerals and trace elements is necessary to characterize a future storage site. Moreover, monitoring and remediation solutions have to be evaluated before storage operations. As part of the ANR project CIPRES, we present here reactive transport works. In a 3D model using ToughReact v.2, we perform different CO2 leakage scenarios in a confined aquifer, considering CO2 gas leakage. The model is based on the Albian aquifer, a strategic water resource. It takes into account groundwater and rock chemistry of the Albian green sand layer (Quartz, Glauconite, Kaolinite) at 700 m deep. The geochemical model was elaborated from experimental data. The aquifer consists in a mesh, divided roughly in 20000 cells making a 60 m thick and a 500 m large layer. Furthermore, cells are subdivided near the leakage point to consider local phenomena (secondary precipitation, sorption/desorption...). The chemical model takes into account kinetics for mineral dissolution, ion exchange and surface complexation. We highlight the importance of sorption processes on trace element transport (As, Zn and Ni) in fresh groundwater. Moreover, we distinguish different geochemical behavior (CO2 plume shape, secondary precipitation, desorption...) according to different horizontal flow rates influenced by the hydrodynamics (regional gradient). Understanding how geochemical processes and regional flows influence water chemistry, allows to ascertain measurement monitoring and verification plan and remediation works in case of leak considering a given location.

  12. What Is the True Color of Fresh Meat? A Biophysical Undergraduate Laboratory Experiment Investigating the Effects of Ligand Binding on Myoglobin Using Optical, EPR, and NMR Spectroscopy

    ERIC Educational Resources Information Center

    Linenberger, Kimberly; Bretz, Stacey Lowery; Crowder, Michael W.; McCarrick, Robert; Lorigan, Gary A.; Tierney, David L.

    2011-01-01

    With an increased focus on integrated upper-level laboratories, we present an experiment integrating concepts from inorganic, biological, and physical chemistry content areas. Students investigate the effects of ligand strength on the spectroscopic properties of the heme center in myoglobin using UV-vis, [superscript 1]H NMR, and EPR…

  13. Micro Wire-Drawing: Experiments And Modelling

    SciTech Connect

    Berti, G. A.; Monti, M.; Bietresato, M.; D'Angelo, L.

    2007-05-17

    In the paper, the authors propose to adopt the micro wire-drawing as a key for investigating models of micro forming processes. The reasons of this choice arose in the fact that this process can be considered a quasi-stationary process where tribological conditions at the interface between the material and the die can be assumed to be constant during the whole deformation. Two different materials have been investigated: i) a low-carbon steel and, ii) a nonferrous metal (copper). The micro hardness and tensile tests performed on each drawn wire show a thin hardened layer (more evident then in macro wires) on the external surface of the wire and hardening decreases rapidly from the surface layer to the center. For the copper wire this effect is reduced and traditional material constitutive model seems to be adequate to predict experimentation. For the low-carbon steel a modified constitutive material model has been proposed and implemented in a FE code giving a better agreement with the experiments.

  14. Full-Scale Cookoff Model Validation Experiments

    SciTech Connect

    McClelland, M A; Rattanapote, M K; Heimdahl, E R; Erikson, W E; Curran, P O; Atwood, A I

    2003-11-25

    This paper presents the experimental results of the third and final phase of a cookoff model validation effort. In this phase of the work, two generic Heavy Wall Penetrators (HWP) were tested in two heating orientations. Temperature and strain gage data were collected over the entire test period. Predictions for time and temperature of reaction were made prior to release of the live data. Predictions were comparable to the measured values and were highly dependent on the established boundary conditions. Both HWP tests failed at a weld located near the aft closure of the device. More than 90 percent of unreacted explosive was recovered in the end heated experiment and less than 30 percent recovered in the side heated test.

  15. Modeling PBX 9501 overdriven release experiments

    SciTech Connect

    Tang, P.K.

    1997-11-01

    High Explosives (HE) performs work by the expansion of its detonation products. Along with the propagation of the detonation wave, the equation of state (EOS) of the products determines the HE performance in an engineering system. The authors show the failure of the standard Jones-Wilkins-Lee (JWL) equation of state (EOS) in modeling the overdriven release experiments of PBX 9501. The deficiency can be tracked back to inability of the same EOS in matching the shock pressure and the sound speed on the Hugoniot in the hydrodynamic regime above the Chapman-Jouguet pressure. After adding correction terms to the principal isentrope of the standard JWL EOS, the authors are able to remedy this shortcoming and the simulation was successful.

  16. Nanofluid Drop Evaporation: Experiment, Theory, and Modeling

    NASA Astrophysics Data System (ADS)

    Gerken, William James

    Nanofluids, stable colloidal suspensions of nanoparticles in a base fluid, have potential applications in the heat transfer, combustion and propulsion, manufacturing, and medical fields. Experiments were conducted to determine the evaporation rate of room temperature, millimeter-sized pendant drops of ethanol laden with varying amounts (0-3% by weight) of 40-60 nm aluminum nanoparticles (nAl). Time-resolved high-resolution drop images were collected for the determination of early-time evaporation rate (D2/D 02 > 0.75), shown to exhibit D-square law behavior, and surface tension. Results show an asymptotic decrease in pendant drop evaporation rate with increasing nAl loading. The evaporation rate decreases by approximately 15% at around 1% to 3% nAl loading relative to the evaporation rate of pure ethanol. Surface tension was observed to be unaffected by nAl loading up to 3% by weight. A model was developed to describe the evaporation of the nanofluid pendant drops based on D-square law analysis for the gas domain and a description of the reduction in liquid fraction available for evaporation due to nanoparticle agglomerate packing near the evaporating drop surface. Model predictions are in relatively good agreement with experiment, within a few percent of measured nanofluid pendant drop evaporation rate. The evaporation of pinned nanofluid sessile drops was also considered via modeling. It was found that the same mechanism for nanofluid evaporation rate reduction used to explain pendant drops could be used for sessile drops. That mechanism is a reduction in evaporation rate due to a reduction in available ethanol for evaporation at the drop surface caused by the packing of nanoparticle agglomerates near the drop surface. Comparisons of the present modeling predictions with sessile drop evaporation rate measurements reported for nAl/ethanol nanofluids by Sefiane and Bennacer [11] are in fairly good agreement. Portions of this abstract previously appeared as: W. J

  17. Development of FT-NIR models for the simultaneous estimation of chlorophyll and nitrogen content in fresh apple (Malus domestica) leaves.

    PubMed

    Tamburini, Elena; Ferrari, Giuseppe; Marchetti, Maria Gabriella; Pedrini, Paola; Ferro, Sergio

    2015-01-01

    Agricultural practices determine the level of food production and, to great extent, the state of the global environment. During the last decades, the indiscriminate recourse to fertilizers as well as the nitrogen losses from land application have been recognized as serious issues of modern agriculture, globally contributing to nitrate pollution. The development of a reliable Near-Infra-Red Spectroscopy (NIRS)-based method, for the simultaneous monitoring of nitrogen and chlorophyll in fresh apple (Malus domestica) leaves, was investigated on a set of 133 samples, with the aim of estimating the nutritional and physiological status of trees, in real time, cheaply and non-destructively. By means of a FT (Fourier Transform)-NIR instrument, Partial Least Squares (PLS) regression models were developed, spanning a concentration range of 0.577%-0.817% for the total Kjeldahl nitrogen (TKN) content (R2 = 0.983; SEC = 0.012; SEP = 0.028), and of 1.534-2.372 mg/g for the total chlorophyll content (R2 = 0.941; SEC = 0.132; SEP = 0.162). Chlorophyll-a and chlorophyll-b contents were also evaluated (R2 = 0.913; SEC = 0.076; SEP = 0.101 and R2 = 0.899; SEC = 0.059; SEP = 0.101, respectively). All calibration models were validated by means of 47 independent samples. The NIR approach allows a rapid evaluation of the nitrogen and chlorophyll contents, and may represent a useful tool for determining nutritional and physiological status of plants, in order to allow a correction of nutrition programs during the season. PMID:25629703

  18. Development of FT-NIR Models for the Simultaneous Estimation of Chlorophyll and Nitrogen Content in Fresh Apple (Malus Domestica) Leaves

    PubMed Central

    Tamburini, Elena; Ferrari, Giuseppe; Marchetti, Maria Gabriella; Pedrini, Paola; Ferro, Sergio

    2015-01-01

    Agricultural practices determine the level of food production and, to great extent, the state of the global environment. During the last decades, the indiscriminate recourse to fertilizers as well as the nitrogen losses from land application have been recognized as serious issues of modern agriculture, globally contributing to nitrate pollution. The development of a reliable Near-Infra-Red Spectroscopy (NIRS)-based method, for the simultaneous monitoring of nitrogen and chlorophyll in fresh apple (Malus domestica) leaves, was investigated on a set of 133 samples, with the aim of estimating the nutritional and physiological status of trees, in real time, cheaply and non-destructively. By means of a FT (Fourier Transform)-NIR instrument, Partial Least Squares (PLS) regression models were developed, spanning a concentration range of 0.577%–0.817% for the total Kjeldahl nitrogen (TKN) content (R2 = 0.983; SEC = 0.012; SEP = 0.028), and of 1.534–2.372 mg/g for the total chlorophyll content (R2 = 0.941; SEC = 0.132; SEP = 0.162). Chlorophyll-a and chlorophyll-b contents were also evaluated (R2 = 0.913; SEC = 0.076; SEP = 0.101 and R2 = 0.899; SEC = 0.059; SEP = 0.101, respectively). All calibration models were validated by means of 47 independent samples. The NIR approach allows a rapid evaluation of the nitrogen and chlorophyll contents, and may represent a useful tool for determining nutritional and physiological status of plants, in order to allow a correction of nutrition programs during the season. PMID:25629703

  19. Ringing load models verified against experiments

    SciTech Connect

    Krokstad, J.R.; Stansberg, C.T.

    1995-12-31

    What is believed to be the main reason for discrepancies between measured and simulated loads in previous studies has been assessed. One has focused on the balance between second- and third-order load components in relation to what is called ``fat body`` load correction. It is important to understand that the use of Morison strip theory in combination with second-order wave theory give rise to second- as well as third-order components in the horizontal force. A proper balance between second- and third-order components in horizontal force is regarded as the most central requirements for a sufficient accurate ringing load model in irregular sea. It is also verified that simulated second-order components are largely overpredicted both in regular and irregular seas. Nonslender diffraction effects are important to incorporate in the FNV formulation in order to reduce the simulated second-order component and to match experiments more closely. A sufficient accurate ringing simulation model with the use of simplified methods is shown to be within close reach. Some further development and experimental verification must however be performed in order to take non-slender effects into account.

  20. Numerical modeling of Deep Impact experiment

    NASA Astrophysics Data System (ADS)

    Sultanov, V. G.; Kim, V. V.; Lomonosov, I. V.; Shutov, A. V.; Fortov, V. E.

    2007-06-01

    The Deep Impact active space experiment has been done [1,2] to study a hypervelocity collision of a metal impactor with the comet 9P/Temple 1. The modeling of impact on solid or porous ice made it possible to conclude: the form and size of crater depends strongly on the density of comet material; the copper impactor does not melt and remains in the solid state; the temperature of ejecta varies from 5000 K for solid ice to 15000 K for porous ice. The impact on moist water- saturated sand demonstrated different results. In this case, the copper impactor practically does not penetrate the comet surface, melts, destroys and the ricochet process takes place. In the case of moist porous sand the produced crater is stretched in the direction of impact. The analysis of modeling results indicates to the presence of volatile easy-vaporized chemical compounds in the cometary surface. The hypothesis that the cometary surface consists of only ice does not agree with experimental and computational data on the forming and spreading of impact ejecta. [1] http://deepimpact.jpl.nasa.gov/home/index.html [2] M. F. A'Hearn et al, Deep Impact: Excavating Comet Tempel 1 // Science, 2005, v.310, pp. 258-264

  1. Collaborative Project: Understanding the Chemical Processes tat Affect Growth rates of Freshly Nucleated Particles

    SciTech Connect

    McMurry, Peter; Smuth, James

    2015-11-12

    This final technical report describes our research activities that have, as the ultimate goal, the development of a model that explains growth rates of freshly nucleated particles. The research activities, which combine field observations with laboratory experiments, explore the relationship between concentrations of gas-phase species that contribute to growth and the rates at which those species are taken up. We also describe measurements of the chemical composition of freshly nucleated particles in a variety of locales, as well as properties (especially hygroscopicity) that influence their effects on climate.

  2. Submarine sand volcanos: experiments and numerical modelling

    NASA Astrophysics Data System (ADS)

    Philippe, P.; Ngoma, J.; Delenne, J.

    2012-12-01

    Fluid overpressure at the bottom of a soil layer may generate fracturation in preferential paths for a cohesive material. But the case of sandy soils is rather different: a significant internal flow is allowed within the material and can potentially induce hydro-mechanical instabilities whose most common example is fluidization. Many works have been devoted to fluidization but very few have the issue of initiation and development of a fluidized zone inside a granular bed, prior entire fluidization of the medium. In this contribution, we report experimental results and numerical simulations on a model system of immersed sand volcanos generated by a localized upward spring of liquid, injected at constant flow-rate at the bottom of a granular layer. Such a localized state of fluidization is relevant for some industrial processes (spouted bed, maintenance of navigable waterways,…) and for several geological issues (kimberlite volcano conduits, fluid venting, oil recovery in sandy soil, More precisely, what is presented here is a comparison between experiments, carried out by direct visualization throughout the medium, and numerical simulations, based on DEM modelling of the grains coupled to resolution of NS equations in the liquid phase (LBM). There is a very good agreement between the experimental phenomenology and the simulation results. When the flow-rate is increased, three regimes are successively observed: static bed, fluidized cavity that does not extend to the top of the layer, and finally fluidization over the entire height of layer that creates a fluidized chimney. A very strong hysteretic effect is present here with an extended range of stability for fluidized cavities when flow-rate is decreased back. This can be interpreted in terms force chains and arches. The influences of grain diameter, layer height and injection width are studied and interpreted using a model previously developed by Zoueshtiagh [1]. Finally, growing rate of the fluidized zone and

  3. Multiwell experiment: reservoir modeling analysis, Volume II

    SciTech Connect

    Horton, A.I.

    1985-05-01

    This report updates an ongoing analysis by reservoir modelers at the Morgantown Energy Technology Center (METC) of well test data from the Department of Energy's Multiwell Experiment (MWX). Results of previous efforts were presented in a recent METC Technical Note (Horton 1985). Results included in this report pertain to the poststimulation well tests of Zones 3 and 4 of the Paludal Sandstone Interval and the prestimulation well tests of the Red and Yellow Zones of the Coastal Sandstone Interval. The following results were obtained by using a reservoir model and history matching procedures: (1) Post-minifracture analysis indicated that the minifracture stimulation of the Paludal Interval did not produce an induced fracture, and extreme formation damage did occur, since a 65% permeability reduction around the wellbore was estimated. The design for this minifracture was from 200 to 300 feet on each side of the wellbore; (2) Post full-scale stimulation analysis for the Paludal Interval also showed that extreme formation damage occurred during the stimulation as indicated by a 75% permeability reduction 20 feet on each side of the induced fracture. Also, an induced fracture half-length of 100 feet was determined to have occurred, as compared to a designed fracture half-length of 500 to 600 feet; and (3) Analysis of prestimulation well test data from the Coastal Interval agreed with previous well-to-well interference tests that showed extreme permeability anisotropy was not a factor for this zone. This lack of permeability anisotropy was also verified by a nitrogen injection test performed on the Coastal Red and Yellow Zones. 8 refs., 7 figs., 2 tabs.

  4. Fresh, Rayed Impact Crater

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-416, 9 July 2003

    This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a fresh, young meteor impact crater on the martian surface. It is less than 400 meters (less than 400 yards) across. While there is no way to know the exact age of this or any other martian surface feature, the rays are very well preserved. On a planet where wind can modify surface features at the present time, a crater with rayed ejecta patterns must be very young indeed. Despite its apparent youth, the crater could still be many hundreds of thousands, if not several million, of years old. This impact scar is located within the much larger Crommelin Crater, near 5.6oN, 10.0oW. Sunlight illuminates the scene from the left.

  5. Modeling active memory: Experiment, theory and simulation

    NASA Astrophysics Data System (ADS)

    Amit, Daniel J.

    2001-06-01

    Neuro-physiological experiments on cognitively performing primates are described to argue that strong evidence exists for localized, non-ergodic (stimulus specific) attractor dynamics in the cortex. The specific phenomena are delay activity distributions-enhanced spike-rate distributions resulting from training, which we associate with working memory. The anatomy of the relevant cortex region and the physiological characteristics of the participating elements (neural cells) are reviewed to provide a substrate for modeling the observed phenomena. Modeling is based on the properties of the integrate-and-fire neural element in presence of an input current of Gaussian distribution. Theory of stochastic processes provides an expression for the spike emission rate as a function of the mean and the variance of the current distribution. Mean-field theory is then based on the assumption that spike emission processes in different neurons in the network are independent, and hence the input current to a neuron is Gaussian. Consequently, the dynamics of the interacting network is reduced to the computation of the mean and the variance of the current received by a cell of a given population in terms of the constitutive parameters of the network and the emission rates of the neurons in the different populations. Within this logic we analyze the stationary states of an unstructured network, corresponding to spontaneous activity, and show that it can be stable only if locally the net input current of a neuron is inhibitory. This is then tested against simulations and it is found that agreement is excellent down to great detail. A confirmation of the independence hypothesis. On top of stable spontaneous activity, keeping all parameters fixed, training is described by (Hebbian) modification of synapses between neurons responsive to a stimulus and other neurons in the module-synapses are potentiated between two excited neurons and depressed between an excited and a quiescent neuron

  6. Global estimates of fresh submarine groundwater discharge

    NASA Astrophysics Data System (ADS)

    Luijendijk, Elco; Gleeson, Tom; Moosdorf, Nils

    2016-04-01

    Fresh submarine groundwater discharge, the flow of fresh groundwater to oceans, may be a significant contributor to the water and chemical budgets of the world's oceans. We present new estimates of the flux of fresh groundwater to the world's oceans. We couple density-dependent numerical simulations of generic models of coastal basins with geospatial databases of hydrogeological parameters and topography to resolve the rate of terrestrially-derived submarine groundwater discharge globally. We compare the model results to a new global compilation of submarine groundwater discharge observations. The results show that terrestrially-derived SGD is highly sensitive to permeability. In most watersheds only a small fraction of groundwater recharge contributes to submarine groundwater discharge, with most recharge instead contributing to terrestrial discharge in the form of baseflow or evapotranspiration. Fresh submarine groundwater discharge is only significant in watersheds that contain highly permeable sediments, such as coarse-grained siliciclastic sediments, karstic carbonates or volcanic deposits. Our estimates of global submarine groundwater discharge are much lower than most previous estimates. However, many tropical and volcanic islands are hotspots of submarine groundwater discharge and solute fluxes towards the oceans. The comparison of model results and data highlights the spatial variability of SGD and the difficulty of scaling up observations.

  7. Microbial safety of fresh produce

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The book entitled “Microbial Safety of Fresh Produce” with 23 chapters is divided into following six sections: Microbial contamination of fresh produce, Pre-harvest strategies, post-harvest interventions, Produce safety during processing and handling, Public, legal, and economic Perspectives, and Re...

  8. Investigation of models for large-scale meteorological prediction experiments

    NASA Technical Reports Server (NTRS)

    Spar, J.

    1975-01-01

    The feasibility of extended and long-range weather prediction by means of global atmospheric models was studied. A number of computer experiments were conducted at GISS with the GISS global general circulation model. Topics discussed include atmospheric response to sea-surface temperature anomalies, and monthly mean forecast experiments with the global model.

  9. Modeling of E-164X Experiment

    SciTech Connect

    Deng, S.; Muggli, P.; Barnes, C.D.; Clayton, C.E.; Decker, F.J.; Fonseca, R.A.; Huang, C.; Hogan, M.J.; Iverson, R.; Johnson, D.K.; Joshi, C.; Katsouleas, T.; Krejcik, P.; Lu, W.; Marsh, K.A.; Mori, W.B.; O'Connell, C.; Oz, E.; Tsung, F.; Zhou, M.M.; /Southern California U. /UCLA /SLAC /Lisbon, IST

    2005-06-28

    In current plasma-based accelerator experiments, very short bunches (100-150 {micro}m for E164 [1] and 10-20 {micro}m for E164X [2] experiment at Stanford Linear Accelerator Center (SLAC)) are used to drive plasma wakes and achieve high accelerating gradients, on the order of 10-100GV/m. The self-fields of such intense bunches can tunnel ionize neutral gases and create the plasma [3,4]. This may completely change the physics of plasma wakes. A 3-D object-oriented fully parallel PIC code OSIRIS [5] is used to simulate various gas types, beam parameters, etc. to support the design of the experiments. The simulation results for real experiment parameters are presented.

  10. Modeling of E-164X Experiment

    SciTech Connect

    Deng, S.; Muggli, P.; Katsouleas, T.; Oz, E.; Barnes, C.D.; Decker, F.J.; Hogan, M.J.; Iverson, R.; Krejcik, P.; O'Connell, C.; Clayton, C.E.; Huang, C.; Johnson, D.K.; Joshi, C.; Lu, W.; Marsh, K.A.; Mori, W.B.; Tsung, F.; Zhou, M.M.; Fonseca, R.A.

    2004-12-07

    In current plasma-based accelerator experiments, very short bunches (100-150{mu}m for E164 and 10-20 {mu}m for E164X experiment at Stanford Linear Accelerator Center (SLAC)) are used to drive plasma wakes and achieve high accelerating gradients, on the order of 10-100GV/m. The self-fields of such intense bunches can tunnel ionize neutral gases and create the plasma. This may completely change the physics of plasma wakes. A 3-D object-oriented fully parallel PIC code OSIRIS is used to simulate various gas types, beam parameters, etc. to support the design of the experiments. The simulation results for real experiment parameters are presented.

  11. Experiments with models committees for flow forecasting

    NASA Astrophysics Data System (ADS)

    Ye, J.; Kayastha, N.; van Andel, S. J.; Fenicia, F.; Solomatine, D. P.

    2012-04-01

    In hydrological modelling typically a single model accounting for all possible hydrological loads, seasons and regimes is used. We argue however, that if a model is not complex enough (and this is the case if conceptual or semi-distributed models are used), then a single model can hardly capture all facets of a complex process, and hence more flexible modelling architectures are required. One possibility here is building several specialized models and making them responsible for various sub-processes. An output would be then a combination of outputs of individual models. In machine learning this approach is widely applied: several learning models are combined in a committee (where each model has a "voting" right with a particular weight). In this presentation we concentrate on optimising the above mentioned process of building a model committee, and on various ways of (a) building individual specialized models (mainly concentrating on calibrating them on various subsets of data and regimes corresponding to hydrological sub-processes), and (b) on various ways of combining their outputs (using the ideas of a fuzzy committee with various parameterisations). In doing so, we extend the approaches developed in [1, 2] and present new results. We consider this problem in multi-objective optimization setting (where objective functions correspond to different hydrological regimes) - leading to a number of Pareto-optimal model combinations from which the most appropriate for a given task can be chosen. Applications of the presented approach to flow forecasting are presented.

  12. Nuclear reaction modeling, verification experiments, and applications

    SciTech Connect

    Dietrich, F.S.

    1995-10-01

    This presentation summarized the recent accomplishments and future promise of the neutron nuclear physics program at the Manuel Lujan Jr. Neutron Scatter Center (MLNSC) and the Weapons Neutron Research (WNR) facility. The unique capabilities of the spallation sources enable a broad range of experiments in weapons-related physics, basic science, nuclear technology, industrial applications, and medical physics.

  13. Modeling the Classic Meselson and Stahl Experiment.

    ERIC Educational Resources Information Center

    D'Agostino, JoBeth

    2001-01-01

    Points out the importance of molecular models in biology and chemistry. Presents a laboratory activity on DNA. Uses different colored wax strips to represent "heavy" and "light" DNA, cesium chloride for identification of small density differences, and three different liquids with varying densities to model gradient centrifugation. (YDS)

  14. Experiments with a Model Water Tunnel

    NASA Technical Reports Server (NTRS)

    Jacobs, Eastman N; Abbott, Ira H

    1930-01-01

    This report describes a model water tunnel built in 1928 by the NACA to investigate the possibility of using water tunnels for aerodynamic investigations at large scales. The model tunnel is similar to an open-throat wind tunnel, but uses water for the working fluid.

  15. Accelerating the connection between experiments and models: The FACE-MDS experience

    NASA Astrophysics Data System (ADS)

    Norby, R. J.; Medlyn, B. E.; De Kauwe, M. G.; Zaehle, S.; Walker, A. P.

    2014-12-01

    The mandate is clear for improving communication between models and experiments to better evaluate terrestrial responses to atmospheric and climatic change. Unfortunately, progress in linking experimental and modeling approaches has been slow and sometimes frustrating. Recent successes in linking results from the Duke and Oak Ridge free-air CO2 enrichment (FACE) experiments with ecosystem and land surface models - the FACE Model-Data Synthesis (FACE-MDS) project - came only after a period of slow progress, but the experience points the way to future model-experiment interactions. As the FACE experiments were approaching their termination, the FACE research community made an explicit attempt to work together with the modeling community to synthesize and deliver experimental data to benchmark models and to use models to supply appropriate context for the experimental results. Initial problems that impeded progress were: measurement protocols were not consistent across different experiments; data were not well organized for model input; and parameterizing and spinning up models that were not designed for simulating a specific site was difficult. Once these problems were worked out, the FACE-MDS project has been very successful in using data from the Duke and ORNL FACE experiment to test critical assumptions in the models. The project showed, for example, that the stomatal conductance model most widely used in models was supported by experimental data, but models did not capture important responses such as increased leaf mass per unit area in elevated CO2, and did not appropriately represent foliar nitrogen allocation. We now have an opportunity to learn from this experience. New FACE experiments that have recently been initiated, or are about to be initiated, include a eucalyptus forest in Australia; the AmazonFACE experiment in a primary, tropical forest in Brazil; and a mature oak woodland in England. Cross-site science questions are being developed that will have a

  16. Experience With Bayesian Image Based Surface Modeling

    NASA Technical Reports Server (NTRS)

    Stutz, John C.

    2005-01-01

    Bayesian surface modeling from images requires modeling both the surface and the image generation process, in order to optimize the models by comparing actual and generated images. Thus it differs greatly, both conceptually and in computational difficulty, from conventional stereo surface recovery techniques. But it offers the possibility of using any number of images, taken under quite different conditions, and by different instruments that provide independent and often complementary information, to generate a single surface model that fuses all available information. I describe an implemented system, with a brief introduction to the underlying mathematical models and the compromises made for computational efficiency. I describe successes and failures achieved on actual imagery, where we went wrong and what we did right, and how our approach could be improved. Lastly I discuss how the same approach can be extended to distinct types of instruments, to achieve true sensor fusion.

  17. As Leaching into Fresh Water from Highly Contaminated Hawaiian Soils

    NASA Astrophysics Data System (ADS)

    Niklis, N. J.; Rubin, K. H.; El-Kadi, A. I.

    2009-12-01

    Arsenic contamination of current and former agricultural soils in Hawaii is an unfortunate legacy of plantation era agricultural practices. Here, we report an investigation of As mobility in fresh water from highly contaminated (0.8 % As) A-zone Hawaiian andisols from the Hamakua Coast of the Island of Hawai’i. Aliquots of the same acidic soil (pH= 5.0) were exposed to fresh water for varying lengths of time and analyzed to quantify the fraction of As and other elements leached from the soil relative to concentrations determined by total digestion. A maximum of 0.04% of As and 0.05% of Fe were removed from the soils in initial rinses and multi-day leaches using 18 megaohm Millipore water, in experiments lasting up to 35 days. Arsenic concentrations were highest in initial soil rinses, indicating that a small fraction of the total As in the soil is either loosely bound or present as a fine-grained, soluble As-bearing phase. During subsequent leaching experiments, arsenic and most other inorganic ions that we analyzed for reached equilibrium after 3 days; Fe reached equilibrium concentrations after 10 days. All soil solutions contained As levels that exceeded the EPA acceptable drinking water limit of 0.01 ppm. However, contaminant transport modeling suggests that As contaminated leachates would not migrate substantially from this site, so that local isolation and storage of contaminated soils would likely be an acceptable containment method.

  18. Turning of slender workpieces: Modeling and experiments

    NASA Astrophysics Data System (ADS)

    Katz, R.; Lee, C. W.; Ulsoy, A. G.; Scott, R. A.

    1989-04-01

    This paper introduces a dynamic cutting force model for turning of slender workpieces, as well as experimental results related to the frequency response of the workpiece in turning. The model is based on a flexible workpiece and rigid machine tool, and a workpiece displacement dependent cutting force. The model is described and studied theoretically as well as experimentally. The experimental studies utilise both cutting force and workpiece vibration measurements in two orthogonal directions. This data is obtained for both cutting and non-cutting conditions, and analysed in the frequency domain. The model was found to be in partial agreement with the experimental results. The experimental procedure described here represents a new method for determining the cutting process damping ratio, based on differences in the measured workpiece natural frequencies with and without cutting.

  19. Hybrid rocket engine, theoretical model and experiment

    NASA Astrophysics Data System (ADS)

    Chelaru, Teodor-Viorel; Mingireanu, Florin

    2011-06-01

    The purpose of this paper is to build a theoretical model for the hybrid rocket engine/motor and to validate it using experimental results. The work approaches the main problems of the hybrid motor: the scalability, the stability/controllability of the operating parameters and the increasing of the solid fuel regression rate. At first, we focus on theoretical models for hybrid rocket motor and compare the results with already available experimental data from various research groups. A primary computation model is presented together with results from a numerical algorithm based on a computational model. We present theoretical predictions for several commercial hybrid rocket motors, having different scales and compare them with experimental measurements of those hybrid rocket motors. Next the paper focuses on tribrid rocket motor concept, which by supplementary liquid fuel injection can improve the thrust controllability. A complementary computation model is also presented to estimate regression rate increase of solid fuel doped with oxidizer. Finally, the stability of the hybrid rocket motor is investigated using Liapunov theory. Stability coefficients obtained are dependent on burning parameters while the stability and command matrixes are identified. The paper presents thoroughly the input data of the model, which ensures the reproducibility of the numerical results by independent researchers.

  20. Teaching "Instant Experience" with Graphical Model Validation Techniques

    ERIC Educational Resources Information Center

    Ekstrøm, Claus Thorn

    2014-01-01

    Graphical model validation techniques for linear normal models are often used to check the assumptions underlying a statistical model. We describe an approach to provide "instant experience" in looking at a graphical model validation plot, so it becomes easier to validate if any of the underlying assumptions are violated.

  1. Foods - fresh vs. frozen or canned

    MedlinePlus

    Frozen foods vs. fresh or canned; Fresh foods vs. frozen or canned; Frozen vegetables versus fresh ... a well-balanced diet. Many people wonder if frozen and canned vegetables are as healthy for you ...

  2. A Fresh Approach

    ERIC Educational Resources Information Center

    Violino, Bob

    2011-01-01

    Facilities and services are a huge drain on community college budgets. They are also vital to the student experience. As funding dries up across the country, many institutions are taking a team approach, working with partner colleges and private service providers to offset costs and generate revenue without sacrificing the services and amenities…

  3. Experiences Using Formal Methods for Requirements Modeling

    NASA Technical Reports Server (NTRS)

    Easterbrook, Steve; Lutz, Robyn; Covington, Rick; Kelly, John; Ampo, Yoko; Hamilton, David

    1996-01-01

    This paper describes three cases studies in the lightweight application of formal methods to requirements modeling for spacecraft fault protection systems. The case studies differ from previously reported applications of formal methods in that formal methods were applied very early in the requirements engineering process, to validate the evolving requirements. The results were fed back into the projects, to improve the informal specifications. For each case study, we describe what methods were applied, how they were applied, how much effort was involved, and what the findings were. In all three cases, the formal modeling provided a cost effective enhancement of the existing verification and validation processes. We conclude that the benefits gained from early modeling of unstable requirements more than outweigh the effort needed to maintain multiple representations.

  4. Silicon Carbide Derived Carbons: Experiments and Modeling

    SciTech Connect

    Kertesz, Miklos

    2011-02-28

    The main results of the computational modeling was: 1. Development of a new genealogical algorithm to generate vacancy clusters in diamond starting from monovacancies combined with energy criteria based on TBDFT energetics. The method revealed that for smaller vacancy clusters the energetically optimal shapes are compact but for larger sizes they tend to show graphitized regions. In fact smaller clusters of the size as small as 12 already show signatures of this graphitization. The modeling gives firm basis for the slit-pore modeling of porous carbon materials and explains some of their properties. 2. We discovered small vacancy clusters and their physical characteristics that can be used to spectroscopically identify them. 3. We found low barrier pathways for vacancy migration in diamond-like materials by obtaining for the first time optimized reaction pathways.

  5. Fundamental Rotorcraft Acoustic Modeling From Experiments (FRAME)

    NASA Technical Reports Server (NTRS)

    Greenwood, Eric

    2011-01-01

    A new methodology is developed for the construction of helicopter source noise models for use in mission planning tools from experimental measurements of helicopter external noise radiation. The models are constructed by employing a parameter identification method to an assumed analytical model of the rotor harmonic noise sources. This new method allows for the identification of individual rotor harmonic noise sources and allows them to be characterized in terms of their individual non-dimensional governing parameters. The method is applied to both wind tunnel measurements and ground noise measurements of two-bladed rotors. The method is shown to match the parametric trends of main rotor harmonic noise, allowing accurate estimates of the dominant rotorcraft noise sources to be made for operating conditions based on a small number of measurements taken at different operating conditions. The ability of this method to estimate changes in noise radiation due to changes in ambient conditions is also demonstrated.

  6. Plasma Reactor Modeling and Validation Experiments

    NASA Technical Reports Server (NTRS)

    Meyyappan, M.; Bose, D.; Hash, D.; Hwang, H.; Cruden, B.; Sharma, S. P.; Rao, M. V. V. S.; Arnold, Jim (Technical Monitor)

    2001-01-01

    Plasma processing is a key processing stop in integrated circuit manufacturing. Low pressure, high density plum reactors are widely used for etching and deposition. Inductively coupled plasma (ICP) source has become popular recently in many processing applications. In order to accelerate equipment and process design, an understanding of the physics and chemistry, particularly, plasma power coupling, plasma and processing uniformity and mechanism is important. This understanding is facilitated by comprehensive modeling and simulation as well as plasma diagnostics to provide the necessary data for model validation which are addressed in this presentation. We have developed a complete code for simulating an ICP reactor and the model consists of transport of electrons, ions, and neutrals, Poisson's equation, and Maxwell's equation along with gas flow and energy equations. Results will be presented for chlorine and fluorocarbon plasmas and compared with data from Langmuir probe, mass spectrometry and FTIR.

  7. Fundamental Rotorcraft Acoustic Modeling from Experiments (FRAME)

    NASA Astrophysics Data System (ADS)

    Greenwood, Eric, II

    2011-12-01

    A new methodology is developed for the construction of helicopter source noise models for use in mission planning tools from experimental measurements of helicopter external noise radiation. The models are constructed by employing a parameter identification method to an assumed analytical model of the rotor harmonic noise sources. This new method allows for the identification of individual rotor harmonic noise sources and allows them to be characterized in terms of their individual non-dimensional governing parameters. The method is applied to both wind tunnel measurements and ground noise measurements of two-bladed rotors. The method is shown to match the parametric trends of main rotor harmonic noise, allowing accurate estimates of the dominant rotorcraft noise sources to be made for operating conditions based on a small number of measurements taken at different operating conditions. The ability of this method to estimate changes in noise radiation due to changes in ambient conditions is also demonstrated.

  8. Modeling transfer of Escherichia coli O157:H7 and Listeria monocytogenes during preparation of fresh-cut salads: impact of cutting and shredding practices.

    PubMed

    Zilelidou, Evangelia A; Tsourou, Virginia; Poimenidou, Sofia; Loukou, Anneza; Skandamis, Panagiotis N

    2015-02-01

    Cutting and shredding of leafy vegetables increases the risk of cross contamination in household settings. The distribution of Escherichia coli O157:H7 and Listeria monocytogenes transfer rates (Tr) between cutting knives and lettuce leaves was investigated and a semi-mechanistic model describing the bacterial transfer during consecutive cuts of leafy vegetables was developed. For both pathogens the distribution of log10Trs from lettuce to knife was towards low values. Conversely log10Trs from knife to lettuce ranged from -2.1 to -0.1 for E. coli O157:H7 and -2.0 to 0 for L. monocytogenes, and indicated a more variable phenomenon. Regarding consecutive cuts, a rapid initial transfer was followed by an asymptotic tail at low populations moving to lettuce or residing on knife. E. coli O157:H7 was transferred at slower rates than L. monocytogenes. These trends were sufficiently described by the transfer-model, with RMSE values of 0.426-0.613 and 0.531-0.908 for L. monocytogenes and E. coli O157:H7, respectively. The model showed good performance in validation trials but underestimated bacterial transfer during extrapolation experiments. The results of the study can provide information regarding cross contamination events in a common household. The constructed model could be a useful tool for the risk-assessment during preparation of leafy-green salads. PMID:25500391

  9. Propagating precipitation waves: experiments and modeling.

    PubMed

    Tinsley, Mark R; Collison, Darrell; Showalter, Kenneth

    2013-12-01

    Traveling precipitation waves, including counterrotating spiral waves, are observed in the precipitation reaction of AlCl3 with NaOH [Volford, A.; et al. Langmuir 2007, 23, 961 - 964]. Experimental and computational studies are carried out to characterize the wave behavior in cross-section configurations. A modified sol-coagulation model is developed that is based on models of Liesegang band and redissolution systems. The dynamics of the propagating waves is characterized in terms of growth and redissolution of a precipitation feature that travels through a migrating band of colloidal precipitate. PMID:24191642

  10. Modelling of dynamic experiments in MCNP5 environment.

    PubMed

    Mosorov, Volodymyr; Zych, Marcin; Hanus, Robert; Petryka, Leszek

    2016-06-01

    The design of radiation measurement systems includes a modelling phase which ascertains the best 3D geometry for a projected gauge. To simulate measured counts by a detector, the widely-used rigorous phenomenological model is used. However, this model does not consider possible source or/and detector movement during a measurement interval. Therefore, the phenomenological model has been successfully modified in order to consider such a displacement during the time sampling interval in dynamic experiments. To validate the proposed model, a simple radiation system was accurately implemented in the MCNP5 code. The experiments confirmed the accuracy of the proposed model. PMID:27058321

  11. Computational Model of Fluorine-20 Experiment

    NASA Astrophysics Data System (ADS)

    Chuna, Thomas; Voytas, Paul; George, Elizabeth; Naviliat-Cuncic, Oscar; Gade, Alexandra; Hughes, Max; Huyan, Xueying; Liddick, Sean; Minamisono, Kei; Weisshaar, Dirk; Paulauskas, Stanley; Ban, Gilles; Flechard, Xavier; Lienard, Etienne

    2015-10-01

    The Conserved Vector Current (CVC) hypothesis of the standard model of the electroweak interaction predicts there is a contribution to the shape of the spectrum in the beta-minus decay of 20F related to a property of the analogous gamma decay of excited 20Ne. To provide a strong test of the CVC hypothesis, a precise measurement of the 20F beta decay spectrum will be taken at the National Superconducting Cyclotron Laboratory. This measurement uses unconventional measurement techniques in that 20F will be implanted directly into a scintillator. As the emitted electrons interact with the detector material, bremsstrahlung interactions occur and the escape of the resultant photons will distort the measured spectrum. Thus, a Monte Carlo simulation has been constructed using EGSnrc radiation transport software. This computational model's intended use is to quantify and correct for distortion in the observed beta spectrum due, primarily, to the aforementioned bremsstrahlung. The focus of this presentation is twofold: the analysis of the computational model itself and the results produced by the model. Wittenberg University.

  12. Modeling and analysis of pinhole occulter experiment

    NASA Technical Reports Server (NTRS)

    Ring, J. R.

    1986-01-01

    The objectives were to improve pointing control system implementation by converting the dynamic compensator from a continuous domain representation to a discrete one; to determine pointing stability sensitivites to sensor and actuator errors by adding sensor and actuator error models to treetops and by developing an error budget for meeting pointing stability requirements; and to determine pointing performance for alternate mounting bases (space station for example).

  13. Flexible robot control: Modeling and experiments

    NASA Technical Reports Server (NTRS)

    Oppenheim, Irving J.; Shimoyama, Isao

    1989-01-01

    Described here is a model and its use in experimental studies of flexible manipulators. The analytical model uses the equivalent of Rayleigh's method to approximate the displaced shape of a flexible link as the static elastic displacement which would occur under end rotations as applied at the joints. The generalized coordinates are thereby expressly compatible with joint motions and rotations in serial link manipulators, because the amplitude variables are simply the end rotations between the flexible link and the chord connecting the end points. The equations for the system dynamics are quite simple and can readily be formulated for the multi-link, three-dimensional case. When the flexible links possess mass and (polar moment of) inertia which are small compared to the concentrated mass and inertia at the joints, the analytical model is exact and displays the additional advantage of reduction in system dimension for the governing equations. Four series of pilot tests have been completed. Studies on a planar single-link system were conducted at Carnegie-Mellon University, and tests conducted at Toshiba Corporation on a planar two-link system were then incorporated into the study. A single link system under three-dimensional motion, displaying biaxial flexure, was then tested at Carnegie-Mellon.

  14. Reaction of seawater with fresh mid-ocean ridge gabbro creates ';atypical' REE pattern and high REE fluid fluxes: Experiments at 425 and 475 °C, 400 and 1000 bar

    NASA Astrophysics Data System (ADS)

    Beermann, O.; Garbe-Schönberg, D.; Holzheid, A. D.

    2013-12-01

    High-temperature MOR hydrothermalism significantly affects ocean chemistry. The Sisters Peak (SP) hydrothermal field at 5°S on the slow-spreading Mid-Atlantic Ridge (MAR) emanates fluids >400°C [1] that have high concentrations of H2, transition metals, and rare earth elements (REE) exhibiting ';atypical' REE pattern characterized by depletions of LREE and HREE relative to MREE and no Eu anomaly [2]. This is in contrast to the ';typical' LREE enrichment and strong positive Eu anomaly known from many MOR vent fluids observed world-wide [e.g., 3]. Besides temperature, the seawater-to-rock ratio (w/r ratio) has significant control on the fluid chemistry [e.g., 4, 5]. To understand how vent fluid REE-signatures are generated during water-rock interaction processes we reacted unaltered gabbro with natural bottom seawater at 425 °C and 400 bar and at 425 and 475 °C at 1000 bar at variable w/r (mass) ratios ranging from 0.5-10 by using cold seal pressure vessels (CSPV). The run durations varied from 3-72 h. Reacted fluids were analysed for major and trace elements by ICP-OES and ICP-MS. In our experiments, ';atypical' REE fluid pattern similar to those of SP fluids were obtained at high w/r ratio (5 and 10) that might be characteristic for focused fluid-flow along e.g., detachment faults at slow-spreading MOR [6]. In contrast, more ';typical'-like REE pattern with elevated LREE and slightly positive Eu anomalies have been reproduced at low w/r ratio (0.5-1). Results of numerical simulations imply that strong positive Eu anomalies of fluids and altered gabbro from high temperature MOR hydrothermal systems can be created by intense rock leaching processes at high w/r ratio (5-10). This suggests that hydrothermal circulation through the ocean crust creates ';typical' REE fluid pattern with strong positive Eu anomalies if seawater reacts with gabbroic host rock that has been already leached in REE at high fluid fluxes. Simulations of the temporal chemical evolution of

  15. Process modelling for materials preparation experiments

    NASA Technical Reports Server (NTRS)

    Rosenberger, Franz; Alexander, J. Iwan D.

    1993-01-01

    The main goals of the research under this grant consist of the development of mathematical tools and measurement of transport properties necessary for high fidelity modeling of crystal growth from the melt and solution, in particular, for the Bridgman-Stockbarger growth of mercury cadmium telluride (MCT) and the solution growth of triglycine sulphate (TGS). Of the tasks described in detail in the original proposal, two remain to be worked on: (1) development of a spectral code for moving boundary problems; and (2) diffusivity measurements on concentrated and supersaturated TGS solutions. Progress made during this seventh half-year period is reported.

  16. Process modelling for materials preparation experiments

    NASA Technical Reports Server (NTRS)

    Rosenberger, Franz; Alexander, J. Iwan D.

    1993-01-01

    The main goals of the research consist of the development of mathematical tools and measurement of transport properties necessary for high fidelity modeling of crystal growth from the melt and solution, in particular for the Bridgman-Stockbarger growth of mercury cadmium telluride (MCT) and the solution growth of triglycine sulphate (TGS). Of the tasks described in detail in the original proposal, two remain to be worked on: development of a spectral code for moving boundary problems, and diffusivity measurements on concentrated and supersaturated TGS solutions. During this eighth half-year period, good progress was made on these tasks.

  17. Process modelling for materials preparation experiments

    NASA Technical Reports Server (NTRS)

    Rosenberger, Franz; Alexander, J. Iwan D.

    1992-01-01

    The development is examined of mathematical tools and measurement of transport properties necessary for high fidelity modeling of crystal growth from the melt and solution, in particular for the Bridgman-Stockbarger growth of mercury cadmium telluride (MCT) and the solution growth of triglycine sulphate (TGS). The tasks include development of a spectral code for moving boundary problems, kinematic viscosity measurements on liquid MCT at temperatures close to the melting point, and diffusivity measurements on concentrated and supersaturated TGS solutions. A detailed description is given of the work performed for these tasks, together with a summary of the resulting publications and presentations.

  18. Recirculating Planar Magnetron Modeling and Experiments

    NASA Astrophysics Data System (ADS)

    Franzi, Matthew; Gilgenbach, Ronald; Hoff, Brad; French, Dave; Lau, Y. Y.

    2011-10-01

    We present simulations and initial experimental results of a new class of crossed field device: Recirculating Planar Magnetrons (RPM). Two geometries of RPM are being explored: 1) Dual planar-magnetrons connected by a recirculating section with axial magnetic field and transverse electric field, and 2) Planar cathode and anode-cavity rings with radial magnetic field and axial electric field. These RPMs have numerous advantages for high power microwave generation by virtue of larger area cathodes and anodes. The axial B-field RPM can be configured in either the conventional or inverted (faster startup) configuration. Two and three-dimensional EM PIC simulations show rapid electron spoke formation and microwave oscillation in pi-mode. Smoothbore prototype axial-B RPM experiments are underway using the MELBA accelerator at parameters of -300 kV, 1-20 kA and pulselengths of 0.5-1 microsecond. Implementation and operation of the first RPM slow wave structure, operating at 1GHz, will be discussed. Research supported by AFOSR, AFRL, L-3 Communications, and Northrop Grumman. Done...processed 1830 records...17:52:57 Beginning APS data extraction...17:52:57

  19. Statistical analysis of target acquisition sensor modeling experiments

    NASA Astrophysics Data System (ADS)

    Deaver, Dawne M.; Moyer, Steve

    2015-05-01

    The U.S. Army RDECOM CERDEC NVESD Modeling and Simulation Division is charged with the development and advancement of military target acquisition models to estimate expected soldier performance when using all types of imaging sensors. Two elements of sensor modeling are (1) laboratory-based psychophysical experiments used to measure task performance and calibrate the various models and (2) field-based experiments used to verify the model estimates for specific sensors. In both types of experiments, it is common practice to control or measure environmental, sensor, and target physical parameters in order to minimize uncertainty of the physics based modeling. Predicting the minimum number of test subjects required to calibrate or validate the model should be, but is not always, done during test planning. The objective of this analysis is to develop guidelines for test planners which recommend the number and types of test samples required to yield a statistically significant result.

  20. Indian Consortia Models: FORSA Libraries' Experiences

    NASA Astrophysics Data System (ADS)

    Patil, Y. M.; Birdie, C.; Bawdekar, N.; Barve, S.; Anilkumar, N.

    2007-10-01

    With increases in prices of journals, shrinking library budgets and cuts in subscriptions to journals over the years, there has been a big challenge facing Indian library professionals to cope with the proliferation of electronic information resources. There have been sporadic efforts by different groups of libraries in forming consortia at different levels. The types of consortia identified are generally based on various models evolved in India in a variety of forms depending upon the participants' affiliations and funding sources. Indian astronomy library professionals have formed a group called Forum for Resource Sharing in Astronomy and Astrophysics (FORSA), which falls under `Open Consortia', wherein participants are affiliated to different government departments. This is a model where professionals willingly come forward and actively support consortia formation; thereby everyone benefits. As such, FORSA has realized four consortia, viz. Nature Online Consortium; Indian Astrophysics Consortium for physics/astronomy journals of Springer/Kluwer; Consortium for Scientific American Online Archive (EBSCO); and Open Consortium for Lecture Notes in Physics (Springer), which are discussed briefly.

  1. The OECI model: the CRO Aviano experience.

    PubMed

    Da Pieve, Lucia; Collazzo, Raffaele; Masutti, Monica; De Paoli, Paolo

    2015-01-01

    In 2012, the "Centro di Riferimento Oncologico" (CRO) National Cancer Institute joined the accreditation program of the Organisation of European Cancer Institutes (OECI) and was one of the first institutes in Italy to receive recognition as a Comprehensive Cancer Center. At the end of the project, a strengths, weaknesses, opportunities, and threats (SWOT) analysis aimed at identifying the pros and cons, both for the institute and of the accreditation model in general, was performed. The analysis shows significant strengths, such as the affinity with other improvement systems and current regulations, and the focus on a multidisciplinary approach. The proposed suggestions for improvement concern mainly the structure of the standards and aim to facilitate the assessment, benchmarking, and sharing of best practices. The OECI accreditation model provided a valuable executive tool and a framework in which we can identify several important development projects. An additional impact for our institute is the participation in the project BenchCan, of which the OECI is lead partner. PMID:27096265

  2. Experiments and Valve Modelling in Thermoacoustic Device

    NASA Astrophysics Data System (ADS)

    Duthil, P.; Baltean Carlès, D.; Bétrancourt, A.; François, M. X.; Yu, Z. B.; Thermeau, J. P.

    2006-04-01

    In a so called heat driven thermoacoustic refrigerator, using either a pulse tube or a lumped boost configuration, heat pumping is induced by Stirling type thermodynamic cycles within the regenerator. The time phase between acoustic pressure and flow rate throughout must then be close to that met for a purely progressive wave. The study presented here relates the experimental characterization of passive elements such as valves, tubes and tanks which are likely to act on this phase relationship when included in the propagation line of the wave resonator. In order to carry out a characterization — from the acoustic point of view — of these elements, systematic measurements of the acoustic field are performed varying various parameters: mean pressure, oscillations frequency, supplied heat power. Acoustic waves are indeed generated by use of a thermoacoustic prime mover driving a pulse tube refrigerator. The experimental results are then compared with the solutions obtained with various one-dimensional linear models including non linear correction factors. It turns out that when using a non symmetrical valve, and for large dissipative effects, the measurements disagree with the linear modelling and non linear behaviour of this particular element is shown.

  3. Infusion of freshly isolated autologous bone marrow derived mononuclear cells prevents endotoxin-induced lung injury in an ex-vivo perfused swine model

    PubMed Central

    2013-01-01

    Introduction The acute respiratory distress syndrome (ARDS), affects up to 150,000 patients per year in the United States. We and other groups have demonstrated that bone marrow derived mesenchymal stromal stem cells prevent ARDS induced by systemic and local administration of endotoxin (lipopolysaccharide (LPS)) in mice. Methods A study was undertaken to determine the effects of the diverse populations of bone marrow derived cells on the pathophysiology of ARDS, using a unique ex-vivo swine preparation, in which only the ventilated lung and the liver are perfused with autologous blood. Six experimental groups were designated as: 1) endotoxin alone, 2) endotoxin + total fresh whole bone marrow nuclear cells (BMC), 3) endotoxin + non-hematopoietic bone marrow cells (CD45 neg), 4) endotoxin + hematopoietic bone marrow cells (CD45 positive), 5) endotoxin + buffy coat and 6) endotoxin + in vitro expanded swine CD45 negative adherent allogeneic bone marrow cells (cultured CD45neg). We measured at different levels the biological consequences of the infusion of the different subsets of cells. The measured parameters were: pulmonary vascular resistance (PVR), gas exchange (PO2), lung edema (lung wet/dry weight), gene expression and serum concentrations of the pro-inflammatory cytokines IL-1β, TNF-α and IL-6. Results Infusion of freshly purified autologous total BMCs, as well as non-hematopoietic CD45(-) bone marrow cells significantly reduced endotoxin-induced pulmonary hypertension and hypoxemia and reduced the lung edema. Also, in the groups that received BMCs and cultured CD45neg we observed a decrease in the levels of IL-1β and TNF-α in plasma. Infusion of hematopoietic CD45(+) bone marrow cells or peripheral blood buffy coat cells did not protect against LPS-induced lung injury. Conclusions We conclude that infusion of freshly isolated autologous whole bone marrow cells and the subset of non-hematopoietic cells can suppress the acute humoral and physiologic

  4. Process modelling for space station experiments

    NASA Technical Reports Server (NTRS)

    Rosenberger, Franz; Alexander, J. Iwan D.

    1988-01-01

    The work performed during the first year 1 Oct. 1987 to 30 Sept. 1988 involved analyses of crystal growth from the melt and from solution. The particular melt growth technique under investigation is directional solidification by the Bridgman-Stockbarger method. Two types of solution growth systems are also being studied. One involves growth from solution in a closed container, the other concerns growth of protein crystals by the hanging drop method. Following discussions with Dr. R. J. Naumann of the Low Gravity Science Division at MSFC it was decided to tackle the analysis of crystal growth from the melt earlier than originally proposed. Rapid progress was made in this area. Work is on schedule and full calculations were underway for some time. Progress was also made in the formulation of the two solution growth models.

  5. FIELD EXPERIMENTS AND MODELING AT CDG AIRPORTS

    NASA Astrophysics Data System (ADS)

    Ramaroson, R.

    2009-12-01

    Richard Ramaroson1,4, Klaus Schaefer2, Stefan Emeis2, Carsten Jahn2, Gregor Schürmann2, Maria Hoffmann2, Mikhael Zatevakhin3, Alexandre Ignatyev3. 1ONERA, Châtillon, France; 4SEAS, Harvard University, Cambridge, USA; 2FZK, Garmisch, Germany; (3)FSUE SPbAEP, St Petersburg, Russia. 2-month field campaigns have been organized at CDG airports in autumn 2004 and summer 2005. Air quality and ground air traffic emissions have been monitored continuously at terminals and taxi-runways, along with meteorological parameters onboard trucks and with a SODAR. This paper analyses the commercial engine emissions characteristics at airports and their effects on gas pollutants and airborne particles coupled to meteorology. LES model results for PM dispersion coupled to microphysics in the PBL are compared to measurements. Winds and temperature at the surface and their vertical profiles have been stored with turbulence. SODAR observations show the time-development of the mixing layer depth and turbulent mixing in summer up to 800m. Active low level jets and their regional extent have been observed and analyzed. PM number and mass size distribution, morphology and chemical contents are investigated. Formation of new ultra fine volatile (UFV) particles in the ambient plume downstream of running engines is observed. Soot particles are mostly observed at significant level at high power thrusts at take-off (TO) and on touch-down whereas at lower thrusts at taxi and aprons ultra the UFV PM emissions become higher. Ambient airborne PM1/2.5 is closely correlated to air traffic volume and shows a maximum beside runways. PM number distribution at airports is composed mainly by volatile UF PM abundant at apron. Ambient PM mass in autumn is higher than in summer. The expected differences between TO and taxi emissions are confirmed for NO, NO2, speciated VOC and CO. NO/NO2 emissions are larger at runways due to higher power. Reactive VOC and CO are more produced at low powers during idling at

  6. Postharvest treatments of fresh produce.

    PubMed

    Mahajan, P V; Caleb, O J; Singh, Z; Watkins, C B; Geyer, M

    2014-06-13

    Postharvest technologies have allowed horticultural industries to meet the global demands of local and large-scale production and intercontinental distribution of fresh produce that have high nutritional and sensory quality. Harvested products are metabolically active, undergoing ripening and senescence processes that must be controlled to prolong postharvest quality. Inadequate management of these processes can result in major losses in nutritional and quality attributes, outbreaks of foodborne pathogens and financial loss for all players along the supply chain, from growers to consumers. Optimal postharvest treatments for fresh produce seek to slow down physiological processes of senescence and maturation, reduce/inhibit development of physiological disorders and minimize the risk of microbial growth and contamination. In addition to basic postharvest technologies of temperature management, an array of others have been developed including various physical (heat, irradiation and edible coatings), chemical (antimicrobials, antioxidants and anti-browning) and gaseous treatments. This article examines the current status on postharvest treatments of fresh produce and emerging technologies, such as plasma and ozone, that can be used to maintain quality, reduce losses and waste of fresh produce. It also highlights further research needed to increase our understanding of the dynamic response of fresh produce to various postharvest treatments. PMID:24797137

  7. Postharvest treatments of fresh produce

    PubMed Central

    Mahajan, P. V.; Caleb, O. J.; Singh, Z.; Watkins, C. B.; Geyer, M.

    2014-01-01

    Postharvest technologies have allowed horticultural industries to meet the global demands of local and large-scale production and intercontinental distribution of fresh produce that have high nutritional and sensory quality. Harvested products are metabolically active, undergoing ripening and senescence processes that must be controlled to prolong postharvest quality. Inadequate management of these processes can result in major losses in nutritional and quality attributes, outbreaks of foodborne pathogens and financial loss for all players along the supply chain, from growers to consumers. Optimal postharvest treatments for fresh produce seek to slow down physiological processes of senescence and maturation, reduce/inhibit development of physiological disorders and minimize the risk of microbial growth and contamination. In addition to basic postharvest technologies of temperature management, an array of others have been developed including various physical (heat, irradiation and edible coatings), chemical (antimicrobials, antioxidants and anti-browning) and gaseous treatments. This article examines the current status on postharvest treatments of fresh produce and emerging technologies, such as plasma and ozone, that can be used to maintain quality, reduce losses and waste of fresh produce. It also highlights further research needed to increase our understanding of the dynamic response of fresh produce to various postharvest treatments. PMID:24797137

  8. Process modelling for materials preparation experiments

    NASA Technical Reports Server (NTRS)

    Rosenberger, Franz; Alexander, J. Iwan D.

    1994-01-01

    The main goals of the research under this grant consist of the development of mathematical tools and measurement techniques for transport properties necessary for high fidelity modelling of crystal growth from the melt and solution. Of the tasks described in detail in the original proposal, two remain to be worked on: development of a spectral code for moving boundary problems, and development of an expedient diffusivity measurement technique for concentrated and supersaturated solutions. We have focused on developing a code to solve for interface shape, heat and species transport during directional solidification. The work involved the computation of heat, mass and momentum transfer during Bridgman-Stockbarger solidification of compound semiconductors. Domain decomposition techniques and preconditioning methods were used in conjunction with Chebyshev spectral methods to accelerate convergence while retaining the high-order spectral accuracy. During the report period we have further improved our experimental setup. These improvements include: temperature control of the measurement cell to 0.1 C between 10 and 60 C; enclosure of the optical measurement path outside the ZYGO interferometer in a metal housing that is temperature controlled to the same temperature setting as the measurement cell; simultaneous dispensing and partial removal of the lower concentration (lighter) solution above the higher concentration (heavier) solution through independently motor-driven syringes; three-fold increase in data resolution by orientation of the interferometer with respect to diffusion direction; and increase of the optical path length in the solution cell to 12 mm.

  9. Underwater Blast Experiments and Modeling for Shock Mitigation

    SciTech Connect

    Glascoe, L; McMichael, L; Vandersall, K; Margraf, J

    2010-03-07

    A simple but novel mitigation concept to enforce standoff distance and reduce shock loading on a vertical, partially-submerged structure is evaluated using scaled aquarium experiments and numerical modeling. Scaled, water tamped explosive experiments were performed using three gallon aquariums. The effectiveness of different mitigation configurations, including air-filled media and an air gap, is assessed relative to an unmitigated detonation using the same charge weight and standoff distance. Experiments using an air-filled media mitigation concept were found to effectively dampen the explosive response of the aluminum plate and reduce the final displacement at plate center by approximately half. The finite element model used for the initial experimental design compares very well to the experimental DIC results both spatially and temporally. Details of the experiment and finite element aquarium models are described including the boundary conditions, Eulerian and Lagrangian techniques, detonation models, experimental design and test diagnostics.

  10. A Community Mentoring Model for STEM Undergraduate Research Experiences

    ERIC Educational Resources Information Center

    Kobulnicky, Henry A.; Dale, Daniel A.

    2016-01-01

    This article describes a community mentoring model for UREs that avoids some of the common pitfalls of the traditional paradigm while harnessing the power of learning communities to provide young scholars a stimulating collaborative STEM research experience.

  11. Applying modeling Results in designing a global tropospheric experiment

    NASA Technical Reports Server (NTRS)

    1982-01-01

    A set of field experiments and advanced modeling studies which provide a strategy for a program of global tropospheric experiments was identified. An expanded effort to develop space applications for trospheric air quality monitoring and studies was recommended. The tropospheric ozone, carbon, nitrogen, and sulfur cycles are addressed. Stratospheric-tropospheric exchange is discussed. Fast photochemical processes in the free troposphere are considered.

  12. Characteristics of a Model Industrial Technology Education Field Experience.

    ERIC Educational Resources Information Center

    Foster, Phillip R.; Kozak, Michael R.

    1986-01-01

    This report contains selected findings from a research project that investigated field experiences in industrial technology education. Funded by the Texas Education Agency, the project addressed the identification of characteristics of a model field experience in industrial technology education. This was accomplished using the Delphi technique.…

  13. Engineering teacher training models and experiences

    NASA Astrophysics Data System (ADS)

    González-Tirados, R. M.

    2009-04-01

    Education Area, we renewed the programme, content and methodology, teaching the course under the name of "Initial Teacher Training Course within the framework of the European Higher Education Area". Continuous Training means learning throughout one's life as an Engineering teacher. They are actions designed to update and improve teaching staff, and are systematically offered on the current issues of: Teaching Strategies, training for research, training for personal development, classroom innovations, etc. They are activities aimed at conceptual change, changing the way of teaching and bringing teaching staff up-to-date. At the same time, the Institution is at the disposal of all teaching staff as a meeting point to discuss issues in common, attend conferences, department meetings, etc. In this Congress we present a justification of both training models and their design together with some results obtained on: training needs, participation, how it is developing and to what extent students are profiting from it.

  14. Arctic pathways of Pacific Water: Arctic Ocean Model Intercomparison experiments

    NASA Astrophysics Data System (ADS)

    Aksenov, Yevgeny; Karcher, Michael; Proshutinsky, Andrey; Gerdes, Rüdiger; de Cuevas, Beverly; Golubeva, Elena; Kauker, Frank; Nguyen, An T.; Platov, Gennady A.; Wadley, Martin; Watanabe, Eiji; Coward, Andrew C.; Nurser, A. J. George

    2016-01-01

    Pacific Water (PW) enters the Arctic Ocean through Bering Strait and brings in heat, fresh water, and nutrients from the northern Bering Sea. The circulation of PW in the central Arctic Ocean is only partially understood due to the lack of observations. In this paper, pathways of PW are investigated using simulations with six state-of-the art regional and global Ocean General Circulation Models (OGCMs). In the simulations, PW is tracked by a passive tracer, released in Bering Strait. Simulated PW spreads from the Bering Strait region in three major branches. One of them starts in the Barrow Canyon, bringing PW along the continental slope of Alaska into the Canadian Straits and then into Baffin Bay. The second begins in the vicinity of the Herald Canyon and transports PW along the continental slope of the East Siberian Sea into the Transpolar Drift, and then through Fram Strait and the Greenland Sea. The third branch begins near the Herald Shoal and the central Chukchi shelf and brings PW into the Beaufort Gyre. In the models, the wind, acting via Ekman pumping, drives the seasonal and interannual variability of PW in the Canadian Basin of the Arctic Ocean. The wind affects the simulated PW pathways by changing the vertical shear of the relative vorticity of the ocean flow in the Canada Basin.

  15. 21 CFR 101.95 - “Fresh,” “freshly frozen,” “fresh frozen,” “frozen fresh.”

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 2 2012-04-01 2012-04-01 false âFresh,â âfreshly frozen,â âfresh frozen,â âfrozen... frozen,” “fresh frozen,” “frozen fresh.” The terms defined in this section may be used on the label or in... state and has not been frozen or subjected to any form of thermal processing or any other form...

  16. 21 CFR 101.95 - “Fresh,” “freshly frozen,” “fresh frozen,” “frozen fresh.”

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 2 2014-04-01 2014-04-01 false âFresh,â âfreshly frozen,â âfresh frozen,â âfrozen... frozen,” “fresh frozen,” “frozen fresh.” The terms defined in this section may be used on the label or in... state and has not been frozen or subjected to any form of thermal processing or any other form...

  17. 21 CFR 101.95 - “Fresh,” “freshly frozen,” “fresh frozen,” “frozen fresh.”

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 2 2013-04-01 2013-04-01 false âFresh,â âfreshly frozen,â âfresh frozen,â âfrozen... frozen,” “fresh frozen,” “frozen fresh.” The terms defined in this section may be used on the label or in... state and has not been frozen or subjected to any form of thermal processing or any other form...

  18. 21 CFR 101.95 - “Fresh,” “freshly frozen,” “fresh frozen,” “frozen fresh.”

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 2 2011-04-01 2011-04-01 false âFresh,â âfreshly frozen,â âfresh frozen,â âfrozen... frozen,” “fresh frozen,” “frozen fresh.” The terms defined in this section may be used on the label or in... state and has not been frozen or subjected to any form of thermal processing or any other form...

  19. Freshly brewed continental crust

    NASA Astrophysics Data System (ADS)

    Gazel, E.; Hayes, J. L.; Caddick, M. J.; Madrigal, P.

    2015-12-01

    Earth's crust is the life-sustaining interface between our planet's deep interior and surface. Basaltic crusts similar to Earth's oceanic crust characterize terrestrial planets in the solar system while the continental masses, areas of buoyant, thick silicic crust, are a unique characteristic of Earth. Therefore, understanding the processes responsible for the formation of continents is fundamental to reconstructing the evolution of our planet. We use geochemical and geophysical data to reconstruct the evolution of the Central American Land Bridge (Costa Rica and Panama) over the last 70 Ma. We also include new preliminary data from a key turning point (~12-6 Ma) from the evolution from an oceanic arc depleted in incompatible elements to a juvenile continental mass in order to evaluate current models of continental crust formation. We also discovered that seismic P-waves (body waves) travel through the crust at velocities closer to the ones observed in continental crust worldwide. Based on global statistical analyses of all magmas produced today in oceanic arcs compared to the global average composition of continental crust we developed a continental index. Our goal was to quantitatively correlate geochemical composition with the average P-wave velocity of arc crust. We suggest that although the formation and evolution of continents may involve many processes, melting enriched oceanic crust within a subduction zone, a process probably more common in the Achaean where most continental landmasses formed, can produce the starting material necessary for juvenile continental crust formation.

  20. A Comparison of Internship Stage Models: Evidence from Intern Experiences

    ERIC Educational Resources Information Center

    Diambra, Joel F.; Cole-Zakrzewski, Kylie G.; Booher, Josh

    2004-01-01

    Human service interns completing their four-year Bachelor of Science degree at the University of Tennessee participated in this study which focused on investigating student internship experiences from the perspective of three different internship stage models. the three models studied include those of Infester and Boss (1998), Sweitzer and King…

  1. Flow dynamics and salt transport in a coastal aquifer driven by a stratified saltwater body: Lab experiment and numerical modeling

    NASA Astrophysics Data System (ADS)

    Oz, Imri; Shalev, Eyal; Yechieli, Yoseph; Gavrieli, Ittai; Gvirtzman, Haim

    2014-04-01

    This paper examines the transient development and the steady-state configuration of groundwater within a coastal aquifer adjacent to a stratified saltwater body. Such systems consist of three different water types: the regional fresh groundwater, and low and high salinity brines forming the upper and lower water layers of the stratified water body, respectively. The dynamics, location and the geometry of the interfaces and the density-driven circulation flows that develop in the aquifer are examined using laboratory experiments and numerical modeling at the same scale. The results show that the transient intrusion of the different water bodies into the aquifer takes place at different rates, and that the locations of the interfaces between them change with time, before reaching steady-state. Under steady-state conditions both the model and the experiments show the existence of three interfaces between the three water types. The numerical model, which is calibrated against the salinity distribution and groundwater discharge rate in the laboratory experiments, allows the quantification of the flow rates and flow patterns within the aquifer. These flow patterns, which cannot be derived from laboratory experiments, show the transient development of three circulation cells which are confined between the three interfaces. These results confirm the hypothesis that has been previously suggested based solely on a steady-state numerical modeling defined by a conceptual understanding. Parametric analysis shows that the creation of three circulation cells and three interfaces is limited to certain conditions and defines the ranges for the creation of this unique system.

  2. Team Preceptorship Model: A Solution for Students' Clinical Experience

    PubMed Central

    Cooper Brathwaite, Angela; Lemonde, Manon

    2011-01-01

    There is a shortage of registered nurses in developed countries, and this shortage is due to the aging nursing workforce, demand for healthcare services, and shortage of nursing professors to teach students. In order to increase the number of clinical placements for nursing students, the authors developed and implemented a collaborative preceptorship model between a Canadian University and Public Health Department to facilitate the clinical experiences of Bachelor of Science of Nursing (BScN) students. This paper describes the Team Preceptorship Model which guided the clinical experience of nine students and 14 preceptors. It also highlights the model's evaluation, strengths, and limitations. PMID:21994893

  3. General Blending Models for Data From Mixture Experiments

    PubMed Central

    Brown, L.; Donev, A. N.; Bissett, A. C.

    2015-01-01

    We propose a new class of models providing a powerful unification and extension of existing statistical methodology for analysis of data obtained in mixture experiments. These models, which integrate models proposed by Scheffé and Becker, extend considerably the range of mixture component effects that may be described. They become complex when the studied phenomenon requires it, but remain simple whenever possible. This article has supplementary material online. PMID:26681812

  4. An Experiment in Determining Software Reliability Model Applicability

    NASA Technical Reports Server (NTRS)

    Nikora, Allen P.

    1995-01-01

    There have been few reports on the behavior of software reliability models under controlled conditions. That is to say, most of the reported experience with the models is during the testing phase of actual projects, during which researchers have little or no control over the data with which they work. Give that failure data for actual projects can be noisy, distorted, and uncertain, reported procedures for determining model applicability may be incomplete.

  5. Investigation of models for large scale meteorological prediction experiments

    NASA Technical Reports Server (NTRS)

    Spar, J.

    1982-01-01

    Long-range numerical prediction and climate simulation experiments with various global atmospheric general circulation models are reported. A chronological listing of the titles of all publications and technical reports already distributed is presented together with an account of the most recent reseach. Several reports on a series of perpetual January climate simulations with the GISS coarse mesh climate model are listed. A set of perpetual July climate simulations with the same model is presented and the results are described.

  6. Numerical Simulation and Cold Modeling experiments on Centrifugal Casting

    NASA Astrophysics Data System (ADS)

    Keerthiprasad, Kestur Sadashivaiah; Murali, Mysore Seetharam; Mukunda, Pudukottah Gopaliengar; Majumdar, Sekhar

    2011-02-01

    In a centrifugal casting process, the fluid flow eventually determines the quality and characteristics of the final product. It is difficult to study the fluid behavior here because of the opaque nature of melt and mold. In the current investigation, numerical simulations of the flow field and visualization experiments on cold models have been carried out for a centrifugal casting system using horizontal molds and fluids of different viscosities to study the effect of different process variables on the flow pattern. The effects of the thickness of the cylindrical fluid annulus formed inside the mold and the effects of fluid viscosity, diameter, and rotational speed of the mold on the hollow fluid cylinder formation process have been investigated. The numerical simulation results are compared with corresponding data obtained from the cold modeling experiments. The influence of rotational speed in a real-life centrifugal casting system has also been studied using an aluminum-silicon alloy. Cylinders of different thicknesses are cast at different rotational speeds, and the flow patterns observed visually in the actual castings are found to be similar to those recorded in the corresponding cold modeling experiments. Reasonable agreement is observed between the results of numerical simulation and the results of cold modeling experiments with different fluids. The visualization study on the hollow cylinders produced in an actual centrifugal casting process also confirm the conclusions arrived at from the cold modeling experiments and numerical simulation in a qualitative sense.

  7. Designing Experiments to Discriminate Families of Logic Models.

    PubMed

    Videla, Santiago; Konokotina, Irina; Alexopoulos, Leonidas G; Saez-Rodriguez, Julio; Schaub, Torsten; Siegel, Anne; Guziolowski, Carito

    2015-01-01

    Logic models of signaling pathways are a promising way of building effective in silico functional models of a cell, in particular of signaling pathways. The automated learning of Boolean logic models describing signaling pathways can be achieved by training to phosphoproteomics data, which is particularly useful if it is measured upon different combinations of perturbations in a high-throughput fashion. However, in practice, the number and type of allowed perturbations are not exhaustive. Moreover, experimental data are unavoidably subjected to noise. As a result, the learning process results in a family of feasible logical networks rather than in a single model. This family is composed of logic models implementing different internal wirings for the system and therefore the predictions of experiments from this family may present a significant level of variability, and hence uncertainty. In this paper, we introduce a method based on Answer Set Programming to propose an optimal experimental design that aims to narrow down the variability (in terms of input-output behaviors) within families of logical models learned from experimental data. We study how the fitness with respect to the data can be improved after an optimal selection of signaling perturbations and how we learn optimal logic models with minimal number of experiments. The methods are applied on signaling pathways in human liver cells and phosphoproteomics experimental data. Using 25% of the experiments, we obtained logical models with fitness scores (mean square error) 15% close to the ones obtained using all experiments, illustrating the impact that our approach can have on the design of experiments for efficient model calibration. PMID:26389116

  8. Configurational diffusion of asphaltenes in fresh and aged catalyst extrudates. Quarterly progress report, June 20, 1993--September 20, 1993

    SciTech Connect

    Guin, J.A.; Tarrer, A.R.

    1993-12-01

    This quarter, we measured the surface areas and effective diffusivities for fresh, spent and regenerated unimodal Criterion 324 and bimodal EXP-AO-60 catalysts. The results showed that the surface areas for spent catalysts decreased greatly due to coke formation and metal deposition during coal liquefaction process. After regeneration, the catalyst surface areas were partially or completely restored. Adsorption equilibrium experiments showed that the adsorption isotherms for quinoline in cyclohexane with these six sample of catalysts could be well represented by Freundlich isotherms. The effective diffusivities with these catalysts were obtained by fitting experimental data with the diffusional model. The results indicated that the effective diffusivity for fresh bimodal catalyst with larger pore size was greater than that for fresh unimodal catalyst with a smaller pore size. After the catalysts were used in a coal liquefaction process, the effective diffusivities decreased to less than 1% of those for fresh catalysts. When the spent catalysts were regenerated in air, the effective diffusivites were recovered to 35--50% of those for fresh catalysts.

  9. Rotating-fluid experiments with an atmospheric general circulation model

    NASA Technical Reports Server (NTRS)

    Geisler, J. E.; Pitcher, E. J.; Malone, R. C.

    1983-01-01

    In order to determine features of rotating fluid flow that are dependent on the geometry, rotating annulus-type experiments are carried out with a numerical model in spherical coordinates. Rather than constructing and testing a model expressly for this purpose, it is found expedient to modify an existing general circulation model of the atmosphere by removing the model physics and replacing the lower boundary with a uniform surface. A regime diagram derived from these model experiments is presented; its major features are interpreted and contrasted with the major features of rotating annulus regime diagrams. Within the wave regime, a narrow region is found where one or two zonal wave numbers are dominant. The results reveal no upper symmetric regime; wave activity at low rotation rates is thought to be maintained by barotropic rather than baroclinic processes.

  10. Cognitive Modeling of Video Game Player User Experience

    NASA Technical Reports Server (NTRS)

    Bohil, Corey J.; Biocca, Frank A.

    2010-01-01

    This paper argues for the use of cognitive modeling to gain a detailed and dynamic look into user experience during game play. Applying cognitive models to game play data can help researchers understand a player's attentional focus, memory status, learning state, and decision strategies (among other things) as these cognitive processes occurred throughout game play. This is a stark contrast to the common approach of trying to assess the long-term impact of games on cognitive functioning after game play has ended. We describe what cognitive models are, what they can be used for and how game researchers could benefit by adopting these methods. We also provide details of a single model - based on decision field theory - that has been successfUlly applied to data sets from memory, perception, and decision making experiments, and has recently found application in real world scenarios. We examine possibilities for applying this model to game-play data.

  11. Modeling a ponded infiltration experiment at Yucca Mountain, NV

    SciTech Connect

    Hudson, D.B.; Guertal, W.R.; Flint, A.L.

    1994-12-31

    Yucca Mountain, Nevada is being evaluated as a potential site for a geologic repository for high level radioactive waste. As part of the site characterization activities at Yucca Mountain, a field-scale ponded infiltration experiment was done to help characterize the hydraulic and infiltration properties of a layered dessert alluvium deposit. Calcium carbonate accumulation and cementation, heterogeneous layered profiles, high evapotranspiration, low precipitation, and rocky soil make the surface difficult to characterize.The effects of the strong morphological horizonation on the infiltration processes, the suitability of measured hydraulic properties, and the usefulness of ponded infiltration experiments in site characterization work were of interest. One-dimensional and two-dimensional radial flow numerical models were used to help interpret the results of the ponding experiment. The objective of this study was to evaluate the results of a ponded infiltration experiment done around borehole UE25 UZN {number_sign}85 (N85) at Yucca Mountain, NV. The effects of morphological horizons on the infiltration processes, lateral flow, and measured soil hydaulic properties were studied. The evaluation was done by numerically modeling the results of a field ponded infiltration experiment. A comparison the experimental results and the modeled results was used to qualitatively indicate the degree to which infiltration processes and the hydaulic properties are understood. Results of the field characterization, soil characterization, borehole geophysics, and the ponding experiment are presented in a companion paper.

  12. Cryogenic Tank Modeling for the Saturn AS-203 Experiment

    NASA Technical Reports Server (NTRS)

    Grayson, Gary D.; Lopez, Alfredo; Chandler, Frank O.; Hastings, Leon J.; Tucker, Stephen P.

    2006-01-01

    A computational fluid dynamics (CFD) model is developed for the Saturn S-IVB liquid hydrogen (LH2) tank to simulate the 1966 AS-203 flight experiment. This significant experiment is the only known, adequately-instrumented, low-gravity, cryogenic self pressurization test that is well suited for CFD model validation. A 4000-cell, axisymmetric model predicts motion of the LH2 surface including boil-off and thermal stratification in the liquid and gas phases. The model is based on a modified version of the commercially available FLOW3D software. During the experiment, heat enters the LH2 tank through the tank forward dome, side wall, aft dome, and common bulkhead. In both model and test the liquid and gases thermally stratify in the low-gravity natural convection environment. LH2 boils at the free surface which in turn increases the pressure within the tank during the 5360 second experiment. The Saturn S-IVB tank model is shown to accurately simulate the self pressurization and thermal stratification in the 1966 AS-203 test. The average predicted pressurization rate is within 4% of the pressure rise rate suggested by test data. Ullage temperature results are also in good agreement with the test where the model predicts an ullage temperature rise rate within 6% of the measured data. The model is based on first principles only and includes no adjustments to bring the predictions closer to the test data. Although quantitative model validation is achieved or one specific case, a significant step is taken towards demonstrating general use of CFD for low-gravity cryogenic fluid modeling.

  13. Merging observations with numerical models in oceanography: some approaches and experiences gained within ECCO (Invited)

    NASA Astrophysics Data System (ADS)

    Heimbach, P.

    2009-12-01

    The problem of extracting information of the state of the polar ice sheets and their evolution through time from sparse observations and with poorly known surface and basal boundary conditions is not unlike the one faced by oceanographers who seek to estimate the global time-varying ocean circulation. Through concerted sea-going campaigns during the World Ocean Circulation Experiment (WOCE), and through the advent of satellite remote sensing dedicated to oceanography the oceanographic community had for the first time nearly global, time-continuous, but diverse, data sets as well as rapidly improving general circulation models (GCMs). Observations remain mostly limited to the near-surface though, cannot be readily compared with each other (altimetry and gravity, for example, measure very different properties and scales), and a quantitative link to the very limited set of in-situ observations, particularly at depth, is difficult. The need to fully exploit the data and models for the purpose of describing and understanding the global ocean circulation and its variability led the establishment of the consortium Estimating the Ocean Circulation and Climate (ECCO). ECCO has sought three-dimensional time-evolving oceanographic estimates which were fully consistent with the available observations, and with the particular GCM being used (primarily the MITgcm), in turn subject to central conservation principles (volume, energy, fresh water, etc.) and, to the degree the GCM was dynamically consistent, with time evolution not subject to artificial jumps or the injection of unphysical sources and sinks e.g. of heat. The science goals of ECCO include the understanding and explanation of the transfers of enthalpy and fresh water to and from the atmosphere and sea ice fields, and so consistency with basic conservation laws is essential. An estimation method which fulfills this requirement, pursued initially by the MIT/SIO and recently by the MIT/AER groups is the adjoint or

  14. Theoretical and experimental studies on low-temperature adsorption drying of fresh ginger

    NASA Astrophysics Data System (ADS)

    Yang, Xiaoxi; Xu, Wei; Ding, Jing; Zhao, Yi

    2006-03-01

    The working principle of low-temperature adsorption drying and the advantages of its application for biological materials drying were introduced in this paper. By using fresh ginger as the drying material, the effects of temperature and relative humidity on its drying characteristics were examined. The results show that the drying rate increases with the temperature increasing or the humidity decreasing. The drying time to the equilibrium is almost the same under different humidity conditions, but low equilibrium moisture content can be acquired under low humidity. The shrinkage characteristics of fresh ginger were also studied. The change of its surface appearance during the drying process was characterized by the new Charged Coupled Device (CCD) and the Environmental Scanning Electron Microscopy (ESEM) technique. A mathematical model of drying dynamics was set up according to the experiments.

  15. Final Report: "Collaborative Project. Understanding the Chemical Processes That Affect Growth Rates of Freshly Nucleated Particles"

    SciTech Connect

    Smith, James N.; McMurry, Peter H.

    2015-11-12

    This final technical report describes our research activities that have, as the ultimate goal, the development of a model that explains growth rates of freshly nucleated particles. The research activities, which combine field observations with laboratory experiments, explore the relationship between concentrations of gas-phase species that contribute to growth and the rates at which those species are taken up. We also describe measurements of the chemical composition of freshly nucleated particles in a variety of locales, as well as properties (especially hygroscopicity) that influence their effects on climate. Our measurements include a self-organized, DOE-ARM funded project at the Southern Great Plains site, the New Particle Formation Study (NPFS), which took place during spring 2013. NPFS data are available to the research community on the ARM data archive, providing a unique suite observations of trace gas and aerosols that are associated with the formation and growth of atmospheric aerosol particles.

  16. Modeling a set of heavy oil aqueous pyrolysis experiments

    SciTech Connect

    Thorsness, C.B.; Reynolds, J.G.

    1996-11-01

    Aqueous pyrolysis experiments, aimed at mild upgrading of heavy oil, were analyzed using various computer models. The primary focus of the analysis was the pressure history of the closed autoclave reactors obtained during the heating of the autoclave to desired reaction temperatures. The models used included a means of estimating nonideal behavior of primary components with regard to vapor liquid equilibrium. The modeling indicated that to match measured autoclave pressures, which often were well below the vapor pressure of water at a given temperature, it was necessary to incorporate water solubility in the oil phase and an activity model for the water in the oil phase which reduced its fugacity below that of pure water. Analysis also indicated that the mild to moderate upgrading of the oil which occurred in experiments that reached 400{degrees}C or more using a FE(III) 2-ethylhexanoate could be reasonably well characterized by a simple first order rate constant of 1.7xl0{sup 8} exp(-20000/T)s{sup {minus}l}. Both gas production and API gravity increase were characterized by this rate constant. Models were able to match the complete pressure history of the autoclave experiments fairly well with relatively simple equilibria models. However, a consistent lower than measured buildup in pressure at peak temperatures was noted in the model calculations. This phenomena was tentatively attributed to an increase in the amount of water entering the vapor phase caused by a change in its activity in the oil phase.

  17. Community Climate System Model (CCSM) Experiments and Output Data

    DOE Data Explorer

    The National Center for Atmospheric Research (NCAR) created the first version of the Community Climate Model (CCM) in 1983 as a global atmosphere model. It was improved in 1994 when NCAR, with support from the National Science Foundation (NSF), developed and incorporated a Climate System Model (CSM) that included atmosphere, land surface, ocean, and sea ice. As the capabilities of the model grew, so did interest in its applications and changes in how it would be managed. A workshop in 1996 set the future management structure, marked the beginning of the second phase of the model, a phase that included full participation of the scientific community, and also saw additional financial support, including support from the Department of Energy. In recognition of these changes, the model was renamed to the Community Climate System Model (CCSM). It began to function as a model with the interactions of land, sea, and air fully coupled, providing computer simulations of Earth's past climate, its present climate, and its possible future climate. The CCSM website at http://www2.cesm.ucar.edu/ describes some of the research that has been done since then: A 300-year run has been performed using the CSM, and results from this experiment have appeared in a special issue of theJournal of Climate, 11, June, 1998. A 125-year experiment has been carried out in which carbon dioxide was described to increase at 1% per year from its present concentration to approximately three times its present concentration. More recently, the Climate of the 20th Century experiment was run, with carbon dioxide and other greenhouse gases and sulfate aerosols prescribed to evolve according to our best knowledge from 1870 to the present. Three scenarios for the 21st century were developed: a "business as usual" experiment, in which greenhouse gases are assumed to increase with no economic constraints; an experiment using the Intergovernmental Panel on Climate Change (IPCC) Scenario A1; and a "policy

  18. Integrated Experiment and Modeling of Insensitive High Explosives

    NASA Astrophysics Data System (ADS)

    Stewart, D. Scott; Lambert, David E.; Yoo, Sunhee; Lieber, M.; Holman, Steven

    2009-06-01

    New design paradigms for insensitive high explosives are being sought for use in munitions applications that require enhanced, safety, reliability and performance. We describe recent work of our group that uses an integrated approach to develop predictive models, guided by experiments. Insensitive explosive can have relatively longer detonation reaction zones and slower reaction rates than their sensitive counterparts. We employ reactive flow models that are constrained by detonation shock dynamics to pose candidate predictive models. We discuss variation of the pressure dependent reaction rate exponent and reaction order, on the length of the supporting reaction zone, the detonation velocity curvature relation, computed critical energy required for initiation, the relation between the diameter effect curve and the corresponding normal detonation velocity curvature relation. We discuss representative characterization experiments carried out at Eglin, AFB and the constraints imposed on models by a standardized experimental characterization sequence.

  19. HCCI in a CFR engine: experiments and detailed kinetic modeling

    SciTech Connect

    Flowers, D; Aceves, S; Smith, R; Torres, J; Girard, J; Dibble, R

    1999-11-05

    Single cylinder engine experiments and chemical kinetic modeling have been performed to study the effect of variations in fuel, equivalence ratio, and intake charge temperature on the start of combustion and the heat release rate. Neat propane and a fuel blend of 15% dimethyl-ether in methane have been studied. The results demonstrate the role of these parameters on the start of combustion, efficiency, imep, and emissions. Single zone kinetic modeling results show the trends consistent with the experimental results.

  20. A Mitigation Scheme for Underwater Blast: Experiments and Modeling

    NASA Astrophysics Data System (ADS)

    Glascoe, Lee; McMichael, Larry; Vandersall, Kevin; Margraf, Jon

    2011-06-01

    A novel but relatively easy-to-implement mitigation concept to enforce standoff distance and reduce shock loading on a vertical, partially-submerged structure is evaluated experimentally using scaled aquarium experiments and numerically using a high-fidelity finite element code. Scaled, water-tamped explosive experiments were performed using aquariums of two different sizes. The effectiveness of different mitigation configurations, including air-filled media and an air gap, is assessed relative to an unmitigated detonation using the same charge weight and standoff distance. Experiments using an air-filled media mitigation concept were found to effectively dampen the explosive response of an aluminum plate and reduce the final displacement at plate center by approximately half; an experiment using an air-gap alone resulted in a focused water jet. The finite element model used for the initial experimental design compares very well to the experimental DIC results both spatially and temporally. Details of the experiment and the finite element models of the aquarium, as well as a larger hypothetical structure, are described including the boundary conditions, numerical techniques, detonation models, experimental design and test diagnostics. This work was performed under the auspices of the US DOE by LLNL under Contract DE-AC52-07NA27344. We would like to thank DHS S & T Directorate for support and assistance.

  1. Experiments and Modeling of G-Jitter Fluid Mechanics

    NASA Technical Reports Server (NTRS)

    Leslie, F. W.; Ramachandran, N.; Whitaker, Ann F. (Technical Monitor)

    2002-01-01

    While there is a general understanding of the acceleration environment onboard an orbiting spacecraft, past research efforts in the modeling and analysis area have still not produced a general theory that predicts the effects of multi-spectral periodic accelerations on a general class of experiments nor have they produced scaling laws that a prospective experimenter can use to assess how an experiment might be affected by this acceleration environment. Furthermore, there are no actual flight experimental data that correlates heat or mass transport with measurements of the periodic acceleration environment. The present investigation approaches this problem with carefully conducted terrestrial experiments and rigorous numerical modeling for better understanding the effect of residual gravity and gentler on experiments. The approach is to use magnetic fluids that respond to an imposed magnetic field gradient in much the same way as fluid density responds to a gravitational field. By utilizing a programmable power source in conjunction with an electromagnet, both static and dynamic body forces can be simulated in lab experiments. The paper provides an overview of the technique and includes recent results from the experiments.

  2. Enriching the Student Experience Through a Collaborative Cultural Learning Model.

    PubMed

    McInally, Wendy; Metcalfe, Sharon; Garner, Bonnie

    2015-01-01

    This article provides a knowledge and understanding of an international, collaborative, cultural learning model for students from the United States and Scotland. Internationalizing the student experience has been instrumental for student learning for the past eight years. Both countries have developed programs that have enriched and enhanced the overall student learning experience, mainly through the sharing of evidence-based care in both hospital and community settings. Student learning is at the heart of this international model, and through practice learning, leadership, and reflective practice, student immersion in global health care and practice is immense. Moving forward, we are seeking new opportunities to explore learning partnerships to provide this collaborative cultural learning experience. PMID:26376575

  3. 21 CFR 101.95 - “Fresh,” “freshly frozen,” “fresh frozen,” “frozen fresh.”

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false âFresh,â âfreshly frozen,â âfresh frozen,â âfrozen fresh.â 101.95 Section 101.95 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION FOOD LABELING Specific Requirements...

  4. Design of Experiments, Model Calibration and Data Assimilation

    SciTech Connect

    Williams, Brian J.

    2014-07-30

    This presentation provides an overview of emulation, calibration and experiment design for computer experiments. Emulation refers to building a statistical surrogate from a carefully selected and limited set of model runs to predict unsampled outputs. The standard kriging approach to emulation of complex computer models is presented. Calibration refers to the process of probabilistically constraining uncertain physics/engineering model inputs to be consistent with observed experimental data. An initial probability distribution for these parameters is updated using the experimental information. Markov chain Monte Carlo (MCMC) algorithms are often used to sample the calibrated parameter distribution. Several MCMC algorithms commonly employed in practice are presented, along with a popular diagnostic for evaluating chain behavior. Space-filling approaches to experiment design for selecting model runs to build effective emulators are discussed, including Latin Hypercube Design and extensions based on orthogonal array skeleton designs and imposed symmetry requirements. Optimization criteria that further enforce space-filling, possibly in projections of the input space, are mentioned. Designs to screen for important input variations are summarized and used for variable selection in a nuclear fuels performance application. This is followed by illustration of sequential experiment design strategies for optimization, global prediction, and rare event inference.

  5. A Model for a Rural School Field Experience.

    ERIC Educational Resources Information Center

    Hull, Ray; Hegtvedt, Kathryn

    Fifteen University of Oregon undergraduate education majors participated in a successful 3-day program of total immersion in rural community living and teaching in Condon, Oregon. The field experience model had unique elements: (1) the course was offered as an alternative to a required course in teaching strategies and student teachers were…

  6. Demonstrating the Experimenting Society Model with Classwide Behavior Management Interventions.

    ERIC Educational Resources Information Center

    Johnson, Taya C.; Stoner, Gary; Green, Susan K.

    1996-01-01

    Demonstrates the experimenting society model using data-based decision making and collaborative consultation to evaluate behavior-management intervention strategies in 25 seventh graders. Each intervention results in improved behavior, but active teaching of classroom rules was determined to be most effective. (Author/JDM)

  7. Design of spatial experiments: Model fitting and prediction

    SciTech Connect

    Fedorov, V.V.

    1996-03-01

    The main objective of the paper is to describe and develop model oriented methods and algorithms for the design of spatial experiments. Unlike many other publications in this area, the approach proposed here is essentially based on the ideas of convex design theory.

  8. ASTP fluid transfer measurement experiment. [using breadboard model

    NASA Technical Reports Server (NTRS)

    Fogal, G. L.

    1974-01-01

    The ASTP fluid transfer measurement experiment flight system design concept was verified by the demonstration and test of a breadboard model. In addition to the breadboard effort, a conceptual design of the corresponding flight system was generated and a full scale mockup fabricated. A preliminary CEI specification for the flight system was also prepared.

  9. EBCE: The Far West Model. Experience-Based Career Education.

    ERIC Educational Resources Information Center

    Far West Lab. for Educational Research and Development, San Francisco, CA.

    This package of handbooks on the Far West Laboratory version of Experience-Based Career Education provides information on the distinctive features of the Far West model. Part 1 on management has four handbooks: program overview; administration (attendance, budget, insurance and liability, schedules, staff, troubleshooting and problem solving);…

  10. Physical mechanism of the Schwarzschild effect in film dosimetry—theoretical model and comparison with experiments

    NASA Astrophysics Data System (ADS)

    Djouguela, A.; Kollhoff, R.; Rühmann, A.; Willborn, K. C.; Harder, D.; Poppe, B.

    2006-09-01

    In consideration of the importance of film dosimetry for the dosimetric verification of IMRT treatment plans, the Schwarzschild effect or failure of the reciprocity law, i.e. the reduction of the net optical density under 'protraction' or 'fractionation' conditions at constant dose, has been experimentally studied for Kodak XOMAT-V (Martens et al 2002 Phys. Med. Biol. 47 2221-34) and EDR 2 dosimetry films (Djouguela et al 2005 Phys. Med. Biol. 50 N317-N321). It is known that this effect results from the competition between two solid-state physics reactions involved in the latent-image formation of the AgBr crystals, the aggregation of two Ag atoms freshly formed from Ag+ ions near radiation-induced occupied electron traps and the spontaneous decomposition of the Ag atoms. In this paper, we are developing a mathematical model of this mechanism which shows that the interplay of the mean lifetime τ of the Ag atoms with the time pattern of the irradiation determines the magnitude of the observed effects of the temporal dose distribution on the net optical density. By comparing this theory with our previous protraction experiments and recent fractionation experiments in which the duration of the pause between fractions was varied, a value of the time constant τ of roughly 10 s at room temperature has been determined for EDR 2. The numerical magnitude of the Schwarzschild effect in dosimetry films under the conditions generally met in radiotherapy amounts to only a few per cent of the net optical density (net OD), so that it can frequently be neglected from the viewpoint of clinical applications. But knowledge of the solid-state physical mechanism and a description in terms of a mathematical model involving a typical time constant of about 10 s are now available to estimate the magnitude of the effect should the necessity arise, i.e. in cases of large fluctuations of the temporal pattern of film exposure.

  11. Antimicrobial packaging for fresh-cut fruits

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fresh-cut fruits are minimally processed produce which are consumed directly at their fresh stage without any further kill step. Microbiological quality and safety are major challenges to fresh-cut fruits. Antimicrobial packaging is one of the innovative food packaging systems that is able to kill o...

  12. Insight Into Sustainability of Fresh Water

    NASA Astrophysics Data System (ADS)

    Simonovic, S. P.

    2002-05-01

    Global modeling often assumes that water is not an issue on the macro scale. WorldWater system dynamics model has been developed for modeling global world water balance and capturing the dynamic character of main variables affecting water availability and use in the future. In spite of not being a novel approach, system dynamics offers (i) a new way for identifying factors that are affecting the future availability of fresh water and provides (ii) insight into the impacts of different development strategies on the future availability of fresh water. WorldWater simulations are clearly demonstrating the strong feedback relation between water availability and different aspects of world development. Results of numerous simulations are contradictory to the assumption made by many global modelers and do confirm that water is an issue on the global scale. Two major observations are made from early model simulations: (a) the use of clean water for dilution and transport of wastewater, if not dealt in other ways, imposes a major stress on the global world water balance; and (b) water use by different sectors is demonstrating quite different dynamics then predicted by classical forecasting tools and other water-models. Inherent linkages between water quantity and quality sectors with food, industry, persistent pollution, technology, and nonrenewable resources sectors of the model create shoot and collapse behavior in water use dynamics. This presentation is discussing a number of different water-related scenarios and their implications on the future water balance. In particular, two extreme scenarios (business as usual - named `Chaos', and unlimited desalination - named `Ocean') will be discussed. Based on the conclusions derived from these two extreme cases a set of more moderate and realistic scenarios (named `Conservation') is proposed.

  13. Event-based Simulation Model for Quantum Optics Experiments

    SciTech Connect

    De Raedt, H.; Michielsen, K.

    2011-03-28

    We present a corpuscular simulation model of optical phenomena that does not require the knowledge of the solution of a wave equation of the whole system and reproduces the results of Maxwell's theory by generating detection events one-by-one. The event-based corpuscular model gives a unified description of multiple-beam fringes of a plane parallel plate and single-photon Mach-Zehnder interferometer, Wheeler's delayed choice, photon tunneling, quantum eraser, two-beam interference, double-slit, Einstein-Podolsky-Rosen-Bohm and Hanbury Brown-Twiss experiments. We also discuss the possibility to refute our corpuscular model.

  14. Scattering Models and Basic Experiments in the Microwave Regime

    NASA Technical Reports Server (NTRS)

    Fung, A. K.; Blanchard, A. J. (Principal Investigator)

    1985-01-01

    The objectives of research over the next three years are: (1) to develop a randomly rough surface scattering model which is applicable over the entire frequency band; (2) to develop a computer simulation method and algorithm to simulate scattering from known randomly rough surfaces, Z(x,y); (3) to design and perform laboratory experiments to study geometric and physical target parameters of an inhomogeneous layer; (4) to develop scattering models for an inhomogeneous layer which accounts for near field interaction and multiple scattering in both the coherent and the incoherent scattering components; and (5) a comparison between theoretical models and measurements or numerical simulation.

  15. Fresh squeezed orange juice odor: a review.

    PubMed

    Perez-Cacho, Pilar Ruiz; Rouseff, Russell L

    2008-08-01

    Fresh orange juice is a highly desirable but unstable product. This review examines analytical findings, odor activity, and variations due to cultivar, sampling methods, manner of juicing, plus possible enzymatic and microbial artifacts. Initial attempts to characterize orange juice odor were based on volatile quantitation and overemphasized the importance of high concentration volatiles. Although over 300 volatiles have been reported from GC-MS analytical studies, this review presents 36 consensus aroma active components from GC-olfactometry studies consisting of 14 aldehydes, 7 esters, 5 terpenes, 6 alcohols, and 4 ketones. Most are trace (microg/L) components. (+)-Limonene is an essential component in orange juice odor although its exact function is still uncertain. Total amounts of volatiles in mechanically squeezed juices are three to 10 times greater than hand-squeezed juices because of elevated peel oil levels. Elevated peel oil changes the relative proportion of several key odorants. Odor active components from solvent extraction studies differ from those collected using headspace techniques as they include volatiles with low vapor pressure such as vanillin. Some reported odorants such as 2,3-butanedione are microbial contamination artifacts. Orange juice odor models confirm that fresh orange aroma is complex as the most successful models contain 23 odorants. PMID:18663618

  16. Evaluation of phytotoxicity of quinoxyfen on fresh market tomatoes, 2012

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This experiment was conducted inTifton, Georgia to evaluate the phytotoxicity of quinoxyfen on fresh market tomatoes in 2012 for the control of bacterial spot and powdery mildew. Four directed foliar applications were applied on a 6-8 day schedule beginning on 2 May and ending on 24 May 2012 at rat...

  17. Evaluation of phytotoxicty of quinoxyfen on fresh market tomatoes, 2011

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This experiment was conducted inTifton, Georgia to evaluate the phytotoxicity of quinoxyfen on fresh market tomatoes in 2011 for the control of bacterial spot and powdery mildew. Four directed foliar applications were applied on a 6-8 day schedule beginning on 19 May and ending on 8 Jun 2011at rate...

  18. Evaluation of phytotoxicity of quinoxyfen on fresh market tomatoes, 2011

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This experiment was conducted inTifton, Georgia to evaluate the phytotoxicity of quinoxyfen on fresh market tomatoes in 2011 for the control of bacterial spot and powdery mildew. Four directed foliar applications were applied on a 6-8 day schedule beginning on 19 May and ending on 8 Jun 2011at rate...

  19. Application of constraint modelling to evaluation of crack growth experiments

    SciTech Connect

    Faleskog, J.; Nilsson, F.; Shehu, S.; Oeberg, H.

    1997-12-01

    A large number of fracture mechanics experiments were carried out using a variety of specimens in order to investigate the applicability of the J-Q approach to initiation and growth of cracks. The study was performed at different temperatures spanning the transition interval of a pressure vessel steel. A comparison of the cleavage initiation levels with the model by Ritchie et al. (RKR) was also conducted. The experiments did not show, although the scatter was large, any systematic geometry effects that could not be explained within the framework of the J-Q concept. This was also the case for surface-cracked plates subjected to nonproportional loading. The trends of the dependence of the initiation on constraint are in qualitative agreement with the RKR model, although this model seems to underestimate this dependence for the current material. The ductile initiation level seems to be fairly independent of constraint but showed a tendency of variation with temperature.

  20. Comparison of a radial fractional transport model with tokamak experiments

    SciTech Connect

    Kullberg, A. Morales, G. J.; Maggs, J. E.

    2014-03-15

    A radial fractional transport model [Kullberg et al., Phys. Rev. E 87, 052115 (2013)], that correctly incorporates the geometric effects of the domain near the origin and removes the singular behavior at the outer boundary, is compared to results of off-axis heating experiments performed in the Rijnhuizen Tokamak Project (RTP), ASDEX Upgrade, JET, and DIII-D tokamak devices. This comparative study provides an initial assessment of the presence of fractional transport phenomena in magnetic confinement experiments. It is found that the nonlocal radial model is robust in describing the steady-state temperature profiles from RTP, but for the propagation of heat waves in ASDEX Upgrade, JET, and DIII-D the model is not clearly superior to predictions based on Fick's law. However, this comparative study does indicate that the order of the fractional derivative, α, is likely a function of radial position in the devices surveyed.

  1. Comparison of a radial fractional transport model with tokamak experiments

    NASA Astrophysics Data System (ADS)

    Kullberg, A.; Morales, G. J.; Maggs, J. E.

    2014-03-01

    A radial fractional transport model [Kullberg et al., Phys. Rev. E 87, 052115 (2013)], that correctly incorporates the geometric effects of the domain near the origin and removes the singular behavior at the outer boundary, is compared to results of off-axis heating experiments performed in the Rijnhuizen Tokamak Project (RTP), ASDEX Upgrade, JET, and DIII-D tokamak devices. This comparative study provides an initial assessment of the presence of fractional transport phenomena in magnetic confinement experiments. It is found that the nonlocal radial model is robust in describing the steady-state temperature profiles from RTP, but for the propagation of heat waves in ASDEX Upgrade, JET, and DIII-D the model is not clearly superior to predictions based on Fick's law. However, this comparative study does indicate that the order of the fractional derivative, α, is likely a function of radial position in the devices surveyed.

  2. Mixture models for gene expression experiments with two species

    PubMed Central

    2014-01-01

    Cross-species research in drug development is novel and challenging. A bivariate mixture model utilizing information across two species was proposed to solve the fundamental problem of identifying differentially expressed genes in microarray experiments in order to potentially improve the understanding of translation between preclinical and clinical studies for drug development. The proposed approach models the joint distribution of treatment effects estimated from independent linear models. The mixture model posits up to nine components, four of which include groups in which genes are differentially expressed in both species. A comprehensive simulation to evaluate the model performance and one application on a real world data set, a mouse and human type II diabetes experiment, suggest that the proposed model, though highly structured, can handle various configurations of differential gene expression and is practically useful on identifying differentially expressed genes, especially when the magnitude of differential expression due to different treatment intervention is weak. In the mouse and human application, the proposed mixture model was able to eliminate unimportant genes and identify a list of genes that were differentially expressed in both species and could be potential gene targets for drug development. PMID:25085578

  3. High pressure experiments with a Mars general circulation model

    NASA Technical Reports Server (NTRS)

    Haberle, R. M.; Pollack, J. B.; Murphy, J. R.; Schaeffer, J.; Lee, H.

    1992-01-01

    The interaction of three physical processes will determine the stability of the Martian polar caps as the surface pressure increases: the greenhouse effect, atmospheric heat transport, and the change in the CO2 frost point temperature. The contribution of each is readily determined in the Mars general circulation model (GCM). Therefore, we have initiated experiments with the GCM to determine how these processes interact, and how the atmosphere-polar cap system responds to increasing surface pressure. The experiments are carried out for northern winter solstice and generally assume the atmosphere to be free of dust. Each experiment starts from resting isothermal conditions and runs for 50 Mars days. Mars' current orbital parameters are used. The experiments are for surface pressures of 120, 480, and 960 mb, which represent 16, 64, and 128 times the current value. To date we have analyzed the 120 mb experiment and the results indicate the contrary to the simpler models, the polar caps actually advance instead of retreat. Other aspects of this investigation are presented.

  4. Behavior analysis by model slope experiment of artificial rainfall

    NASA Astrophysics Data System (ADS)

    Park, Min Cheol

    2016-03-01

    In this study, we performed a model slope experiment with rainfall seepage, and the results were compared and verified with the unsaturated slope stability analysis method. In the model slope experiment, we measured the changes in water content and matric suction due to rainfall seepage, and determined the time at which the slope failure occurred and the shape of the failure. In addition, we compared and verified the changes in the factor of safety and the shape of the failure surface, which was calculated from the unsaturated slope stability analysis with the model experiment. From the results of experiment and analysis, it is concluded that the unsaturated slope stability analysis can be used to accurately analyze and predict rainfall-induced slope failure. It is also concluded that in seepage analysis, setting the initial conditions and boundary conditions is very important. If engineers will use the measured porewater pressure or matric suction, the accuracy of analysis can be enhanced. The real-time monitoring system of porewater pressure or matric suction can be used as a warning of rainfall-induced slope failure.

  5. Experiences & Tools from Modeling Instruction Applied to Earth Sciences

    NASA Astrophysics Data System (ADS)

    Cervenec, J.; Landis, C. E.

    2012-12-01

    The Framework for K-12 Science Education calls for stronger curricular connections within the sciences, greater depth in understanding, and tasks higher on Bloom's Taxonomy. Understanding atmospheric sciences draws on core knowledge traditionally taught in physics, chemistry, and in some cases, biology. If this core knowledge is not conceptually sound, well retained, and transferable to new settings, understanding the causes and consequences of climate changes become a task in memorizing seemingly disparate facts to a student. Fortunately, experiences and conceptual tools have been developed and refined in the nationwide network of Physics Modeling and Chemistry Modeling teachers to build necessary understanding of conservation of mass, conservation of energy, particulate nature of matter, kinetic molecular theory, and particle model of light. Context-rich experiences are first introduced for students to construct an understanding of these principles and then conceptual tools are deployed for students to resolve misconceptions and deepen their understanding. Using these experiences and conceptual tools takes an investment of instructional time, teacher training, and in some cases, re-envisioning the format of a science classroom. There are few financial barriers to implementation and students gain a greater understanding of the nature of science by going through successive cycles of investigation and refinement of their thinking. This presentation shows how these experiences and tools could be used in an Earth Science course to support students developing conceptually rich understanding of the atmosphere and connections happening within.

  6. Design and modeling of small scale multiple fracturing experiments

    SciTech Connect

    Cuderman, J F

    1981-12-01

    Recent experiments at the Nevada Test Site (NTS) have demonstrated the existence of three distinct fracture regimes. Depending on the pressure rise time in a borehole, one can obtain hydraulic, multiple, or explosive fracturing behavior. The use of propellants rather than explosives in tamped boreholes permits tailoring of the pressure risetime over a wide range since propellants having a wide range of burn rates are available. This technique of using the combustion gases from a full bore propellant charge to produce controlled borehole pressurization is termed High Energy Gas Fracturing (HEGF). Several series of HEGF, in 0.15 m and 0.2 m diameter boreholes at 12 m depths, have been completed in a tunnel complex at NTS where mineback permitted direct observation of fracturing obtained. Because such large experiments are costly and time consuming, smaller scale experiments are desirable, provided results from small experiments can be used to predict fracture behavior in larger boreholes. In order to design small scale gas fracture experiments, the available data from previous HEGF experiments were carefully reviewed, analytical elastic wave modeling was initiated, and semi-empirical modeling was conducted which combined predictions for statically pressurized boreholes with experimental data. The results of these efforts include (1) the definition of what constitutes small scale experiments for emplacement in a tunnel complex at the Nevada Test Site, (2) prediction of average crack radius, in ash fall tuff, as a function of borehole size and energy input per unit length, (3) definition of multiple-hydraulic and multiple-explosive fracture boundaries as a function of boreholes size and surface wave velocity, (4) semi-empirical criteria for estimating stress and acceleration, and (5) a proposal that multiple fracture orientations may be governed by in situ stresses.

  7. First Results of the Regional Earthquake Likelihood Models Experiment

    USGS Publications Warehouse

    Schorlemmer, D.; Zechar, J.D.; Werner, M.J.; Field, E.H.; Jackson, D.D.; Jordan, T.H.

    2010-01-01

    The ability to successfully predict the future behavior of a system is a strong indication that the system is well understood. Certainly many details of the earthquake system remain obscure, but several hypotheses related to earthquake occurrence and seismic hazard have been proffered, and predicting earthquake behavior is a worthy goal and demanded by society. Along these lines, one of the primary objectives of the Regional Earthquake Likelihood Models (RELM) working group was to formalize earthquake occurrence hypotheses in the form of prospective earthquake rate forecasts in California. RELM members, working in small research groups, developed more than a dozen 5-year forecasts; they also outlined a performance evaluation method and provided a conceptual description of a Testing Center in which to perform predictability experiments. Subsequently, researchers working within the Collaboratory for the Study of Earthquake Predictability (CSEP) have begun implementing Testing Centers in different locations worldwide, and the RELM predictability experiment-a truly prospective earthquake prediction effort-is underway within the U. S. branch of CSEP. The experiment, designed to compare time-invariant 5-year earthquake rate forecasts, is now approximately halfway to its completion. In this paper, we describe the models under evaluation and present, for the first time, preliminary results of this unique experiment. While these results are preliminary-the forecasts were meant for an application of 5 years-we find interesting results: most of the models are consistent with the observation and one model forecasts the distribution of earthquakes best. We discuss the observed sample of target earthquakes in the context of historical seismicity within the testing region, highlight potential pitfalls of the current tests, and suggest plans for future revisions to experiments such as this one. ?? 2010 The Author(s).

  8. Nanodosimetry of electrons: analysis by experiment and modelling.

    PubMed

    Bantsar, A; Pszona, S

    2015-09-01

    Nanodosimetry experiments for high-energy electrons from a (131)I radioactive source interacting with gaseous nitrogen with sizes on a scale equivalent to the mass per area of a segment of DNA and nucleosome are described. The discrete ionisation cluster-size distributions were measured in experiments carried out with the Jet Counter. The experimental results were compared with those obtained by Monte Carlo modelling. The descriptors of radiation damages have been derived from the data obtained from ionisation cluster-size distributions. PMID:25971347

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

    SciTech Connect

    Luo, Mingxing.

    1993-01-01

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

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

    SciTech Connect

    Luo, Mingxing

    1993-04-01

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

  11. Modeling and Simulation of Fluid Mixing Laser Experiments and Supernova

    SciTech Connect

    James Glimm

    2009-06-04

    The three year plan for this project was to develop novel theories and advanced simulation methods leading to a systematic understanding of turbulent mixing. A primary focus is the comparison of simulation models (Direct Numerical Simulation (DNS), Large Eddy Simulations (LES), full two fluid simulations and subgrid averaged models) to experiments. The comprehension and reduction of experimental and simulation data are central goals of this proposal. We model 2D and 3D perturbations of planar or circular interfaces. We compare these tests with models derived from averaged equations (our own and those of others). As a second focus, we develop physics based subgrid simulation models of diffusion across an interface, with physical but no numerical mass diffusion. Multiple layers and reshock are considered here.

  12. Modeling and Simulation of Fluid Mixing Laser Experiments and Supernova

    SciTech Connect

    Glimm, James

    2008-06-24

    The three year plan for this project is to develop novel theories and advanced simulation methods leading to a systematic understanding of turbulent mixing. A primary focus is the comparison of simulation models (both Direct Numerical Simulation and subgrid averaged models) to experiments. The comprehension and reduction of experimental and simulation data are central goals of this proposal. We will model 2D and 3D perturbations of planar interfaces. We will compare these tests with models derived from averaged equations (our own and those of others). As a second focus, we will develop physics based subgrid simulation models of diffusion across an interface, with physical but no numerical mass diffusion. We will conduct analytic studies of mix, in support of these objectives. Advanced issues, including multiple layers and reshock, will be considered.

  13. E-health stakeholders experiences with clinical modelling and standardizations.

    PubMed

    Gøeg, Kirstine Rosenbeck; Elberg, Pia Britt; Højen, Anne Randorff

    2015-01-01

    Stakeholders in e-health such as governance officials, health IT-implementers and vendors have to co-operate to achieve the goal of a future-proof interoperable e-health infrastructure. Co-operation requires knowledge on the responsibility and competences of stakeholder groups. To increase awareness on clinical modeling and standardization we conducted a workshop for Danish and a few Norwegian e-health stakeholders' and made them discuss their views on different aspects of clinical modeling using a theoretical model as a point of departure. Based on the model, we traced stakeholders' experiences. Our results showed there was a tendency that stakeholders were more familiar with e-health requirements than with design methods, clinical information models and clinical terminology as they are described in the scientific literature. The workshop made it possible for stakeholders to discuss their roles and expectations to each other. PMID:25991150

  14. Analysis of NIF experiments with the minimal energy implosion model

    SciTech Connect

    Cheng, B. Kwan, T. J. T.; Wang, Y. M.; Merrill, F. E.; Batha, S. H.; Cerjan, C. J.

    2015-08-15

    We apply a recently developed analytical model of implosion and thermonuclear burn to fusion capsule experiments performed at the National Ignition Facility that used low-foot and high-foot laser pulse formats. Our theoretical predictions are consistent with the experimental data. Our studies, together with neutron image analysis, reveal that the adiabats of the cold fuel in both low-foot and high-foot experiments are similar. That is, the cold deuterium-tritium shells in those experiments are all in a high adiabat state at the time of peak implosion velocity. The major difference between low-foot and high-foot capsule experiments is the growth of the shock-induced instabilities developed at the material interfaces which lead to fuel mixing with ablator material. Furthermore, we have compared the NIF capsules performance with the ignition criteria and analyzed the alpha particle heating in the NIF experiments. Our analysis shows that alpha heating was appreciable only in the high-foot experiments.

  15. Analysis of NIF experiments with the minimal energy implosion model

    NASA Astrophysics Data System (ADS)

    Cheng, B.; Kwan, T. J. T.; Wang, Y. M.; Merrill, F. E.; Cerjan, C. J.; Batha, S. H.

    2015-08-01

    We apply a recently developed analytical model of implosion and thermonuclear burn to fusion capsule experiments performed at the National Ignition Facility that used low-foot and high-foot laser pulse formats. Our theoretical predictions are consistent with the experimental data. Our studies, together with neutron image analysis, reveal that the adiabats of the cold fuel in both low-foot and high-foot experiments are similar. That is, the cold deuterium-tritium shells in those experiments are all in a high adiabat state at the time of peak implosion velocity. The major difference between low-foot and high-foot capsule experiments is the growth of the shock-induced instabilities developed at the material interfaces which lead to fuel mixing with ablator material. Furthermore, we have compared the NIF capsules performance with the ignition criteria and analyzed the alpha particle heating in the NIF experiments. Our analysis shows that alpha heating was appreciable only in the high-foot experiments.

  16. Computer simulation models are implementable as replacements for animal experiments.

    PubMed

    Badyal, Dinesh K; Modgill, Vikas; Kaur, Jasleen

    2009-04-01

    It has become increasingly difficult to perform animal experiments, because of issues related to the procurement of animals, and strict regulations and ethical issues related to their use. As a result, it is felt that the teaching of pharmacology should be more clinically oriented and that unnecessary animal experimentation should be avoided. Although a number of computer simulation models (CSMs) are available, they are not being widely used. Interactive demonstrations were conducted to encourage the departmental faculty to use CSMs. Four different animal experiments were selected, that dealt with actions of autonomic drugs. The students observed demonstrations of animal experiments involving conventional methods and the use of CSMs. This was followed by hands-on experience of the same experiment, but using CSMs in small groups, instead of hands-on experience with the animal procedures. Test scores and feedback showed that there was better understanding of the mechanisms of action of the drugs, gained in a shorter time. The majority of the students found the teaching programme used to be good to excellent. CSMs can be used repeatedly and independently by students, and this avoids unnecessary experimentation and also causing pain and trauma to animals. The CSM programme can be implemented in existing teaching schedules for pharmacology undergraduate teaching with basic infrastructure support, and is readily adaptable for use by other institutes. PMID:19453215

  17. Multicomponent reactive transport modeling of uranium bioremediation field experiments

    SciTech Connect

    Fang, Yilin; Yabusaki, Steven B.; Morrison, Stan J.; Amonette, James E.; Long, Philip E.

    2009-10-15

    Biostimulation field experiments with acetate amendment are being performed at a former uranium mill tailings site in Rifle, Colorado, to investigate subsurface processes controlling in situ bioremediation of uranium-contaminated groundwater. An important part of the research is identifying and quantifying field-scale models of the principal terminal electron-accepting processes (TEAPs) during biostimulation and the consequent biogeochemical impacts to the subsurface receiving environment. Integrating abiotic chemistry with the microbially mediated TEAPs in the reaction network brings into play geochemical observations (e.g., pH, alkalinity, redox potential, major ions, and secondary minerals) that the reactive transport model must recognize. These additional constraints provide for a more systematic and mechanistic interpretation of the field behaviors during biostimulation. The reaction network specification developed for the 2002 biostimulation field experiment was successfully applied without additional calibration to the 2003 and 2007 field experiments. The robustness of the model specification is significant in that 1) the 2003 biostimulation field experiment was performed with 3 times higher acetate concentrations than the previous biostimulation in the same field plot (i.e., the 2002 experiment), and 2) the 2007 field experiment was performed in a new unperturbed plot on the same site. The biogeochemical reactive transport simulations accounted for four TEAPs, two distinct functional microbial populations, two pools of bioavailable Fe(III) minerals (iron oxides and phyllosilicate iron), uranium aqueous and surface complexation, mineral precipitation, and dissolution. The conceptual model for bioavailable iron reflects recent laboratory studies with sediments from the Old Rifle Uranium Mill Tailings Remedial Action (UMTRA) site that demonstrated that the bulk (~90%) of Fe(III) bioreduction is associated with the phyllosilicates rather than the iron oxides

  18. Electrical Resistivity Monitoring of Voids: Results of Dynamic Modeling Experiments

    NASA Astrophysics Data System (ADS)

    Lane, J. W.; Day-Lewis, F. D.; Singha, K.

    2006-05-01

    Remote, non-invasive detection of voids is a challenging problem for environmental and engineering investigations in karst terrain. Many geophysical methods including gravity, electrical, electromagnetic, magnetic, and seismic have potential to detect voids in the subsurface; lithologic heterogeneity and method- specific sources of noise, however, can mask the geophysical signatures of voids. New developments in automated, autonomous geophysical monitoring technology now allow for void detection using differential geophysics. We propose automated collection of electrical resistivity measurements over time. This dynamic approach exploits changes in subsurface electrical properties related to void growth or water-table fluctuation in order to detect voids that would be difficult or impossible to detect using static imaging approaches. We use a series of synthetic modeling experiments to demonstrate the potential of difference electrical resistivity tomography for finding (1) voids that develop vertically upward under a survey line (e.g., an incipient sinkhole); (2) voids that develop horizontally toward a survey line (e.g., a tunnel); and (3) voids that are influenced by changing hydrologic conditions (e.g., void saturation and draining). Synthetic datasets are simulated with a 3D finite-element model, but the inversion assumes a 2D forward model to mimic conventional practice. The results of the synthetic modeling experiments provide insights useful for planning and implementing field-scale monitoring experiments using electrical methods.

  19. Simulation model for the closed plant experiment facility of CEEF.

    PubMed

    Abe, Koichi; Ishikawa, Yoshio; Kibe, Seishiro; Nitta, Keiji

    2005-01-01

    The Closed Ecology Experiment Facilities (CEEF) is a testbed for Controlled Ecological Life Support Systems (CELSS) investigations. CEEF including the physico-chemical material regenerative system has been constructed for the experiments of material circulation among plants, breeding animals and crew of CEEF. Because CEEF is a complex system, an appropriate schedule for the operation must be prepared in advance. The CEEF behavioral Prediction System, CPS, that will help to confirm the operation schedule, is under development. CPS will simulate CEEFs behavior with data (conditions of equipments, quantity of materials in tanks, etc.) of CEEF and an operation schedule that will be made by the operation team everyday, before the schedule will be carried out. The result of the simulation will show whether the operation schedule is appropriate or not. In order to realize CPS, models of the simulation program that is installed in CPS must mirror the real facilities of CEEF. For the first step of development, a flexible algorithm of the simulation program was investigated. The next step was development of a replicate simulation model of the material circulation system for the Closed Plant Experiment Facility (CPEF) that is a part of CEEF. All the parts of a real material circulation system for CPEF are connected together and work as a complex mechanism. In the simulation model, the system was separated into 38 units according to its operational segmentation. In order to develop each model for its corresponding unit, specifications for the model were fixed based on the specifications of the real part. These models were put into a simulation model for the system. PMID:16175692

  20. Simulation model for the closed plant experiment facility of CEEF

    NASA Astrophysics Data System (ADS)

    Abe, Koichi; Ishikawa, Yoshio; Kibe, Seishiro; Nitta, Keiji

    The Closed Ecology Experiment Facilities (CEEF) is a testbed for Controlled Ecological Life Support Systems (CELSS) investigations. CEEF including the physico-chemical material regenerative system has been constructed for the experiments of material circulation among plants, breeding animals and crew of CEEF. Because CEEF is a complex system, an appropriate schedule for the operation must be prepared in advance. The CEEF behavioral Prediction System, CPS, that will help to confirm the operation schedule, is under development. CPS will simulate CEEFs behavior with data (conditions of equipments, quantity of materials in tanks, etc.) of CEEF and an operation schedule that will be made by the operation team everyday, before the schedule will be carried out. The result of the simulation will show whether the operation schedule is appropriate or not. In order to realize CPS, models of the simulation program that is installed in CPS must mirror the real facilities of CEEF. For the first step of development, a flexible algorithm of the simulation program was investigated. The next step was development of a replicate simulation model of the material circulation system for the Closed Plant Experiment Facility (CPEF) that is a part of CEEF. All the parts of a real material circulation system for CPEF are connected together and work as a complex mechanism. In the simulation model, the system was separated into 38 units according to its operational segmentation. In order to develop each model for its corresponding unit, specifications for the model were fixed based on the specifications of the real part. These models were put into a simulation model for the system.

  1. Modeling HEDLA magnetic field generation experiments on laser facilities

    NASA Astrophysics Data System (ADS)

    Fatenejad, M.; Bell, A. R.; Benuzzi-Mounaix, A.; Crowston, R.; Drake, R. P.; Flocke, N.; Gregori, G.; Koenig, M.; Krauland, C.; Lamb, D.; Lee, D.; Marques, J. R.; Meinecke, J.; Miniati, F.; Murphy, C. D.; Park, H.-S.; Pelka, A.; Ravasio, A.; Remington, B.; Reville, B.; Scopatz, A.; Tzeferacos, P.; Weide, K.; Woolsey, N.; Young, R.; Yurchak, R.

    2013-03-01

    The Flash Center is engaged in a collaboration to simulate laser driven experiments aimed at understanding the generation and amplification of cosmological magnetic fields using the FLASH code. In these experiments a laser illuminates a solid plastic or graphite target launching an asymmetric blast wave into a chamber which contains either Helium or Argon at millibar pressures. Induction coils placed several centimeters away from the target detect large scale magnetic fields on the order of tens to hundreds of Gauss. The time dependence of the magnetic field is consistent with generation via the Biermann battery mechanism near the blast wave. Attempts to perform simulations of these experiments using the FLASH code have uncovered previously unreported numerical difficulties in modeling the Biermann battery mechanism near shock waves which can lead to the production of large non-physical magnetic fields. We report on these difficulties and offer a potential solution.

  2. Calibration of Predictor Models Using Multiple Validation Experiments

    NASA Technical Reports Server (NTRS)

    Crespo, Luis G.; Kenny, Sean P.; Giesy, Daniel P.

    2015-01-01

    This paper presents a framework for calibrating computational models using data from several and possibly dissimilar validation experiments. The offset between model predictions and observations, which might be caused by measurement noise, model-form uncertainty, and numerical error, drives the process by which uncertainty in the models parameters is characterized. The resulting description of uncertainty along with the computational model constitute a predictor model. Two types of predictor models are studied: Interval Predictor Models (IPMs) and Random Predictor Models (RPMs). IPMs use sets to characterize uncertainty, whereas RPMs use random vectors. The propagation of a set through a model makes the response an interval valued function of the state, whereas the propagation of a random vector yields a random process. Optimization-based strategies for calculating both types of predictor models are proposed. Whereas the formulations used to calculate IPMs target solutions leading to the interval value function of minimal spread containing all observations, those for RPMs seek to maximize the models' ability to reproduce the distribution of observations. Regarding RPMs, we choose a structure for the random vector (i.e., the assignment of probability to points in the parameter space) solely dependent on the prediction error. As such, the probabilistic description of uncertainty is not a subjective assignment of belief, nor is it expected to asymptotically converge to a fixed value, but instead it casts the model's ability to reproduce the experimental data. This framework enables evaluating the spread and distribution of the predicted response of target applications depending on the same parameters beyond the validation domain.

  3. Fracture Mechanics Modelling of an In Situ Concrete Spalling Experiment

    NASA Astrophysics Data System (ADS)

    Siren, Topias; Uotinen, Lauri; Rinne, Mikael; Shen, Baotang

    2015-07-01

    During the operation of nuclear waste disposal facilities, some sprayed concrete reinforced underground spaces will be in use for approximately 100 years. During this time of use, the local stress regime will be altered by the radioactive decay heat. The change in the stress state will impose high demands on sprayed concrete, as it may suffer stress damage or lose its adhesion to the rock surface. It is also unclear what kind of support pressure the sprayed concrete layer will apply to the rock. To investigate this, an in situ experiment is planned in the ONKALO underground rock characterization facility at Olkiluoto, Finland. A vertical experimental hole will be concreted, and the surrounding rock mass will be instrumented with heat sources, in order to simulate an increase in the surrounding stress field. The experiment is instrumented with an acoustic emission system for the observation of rock failure and temperature, as well as strain gauges to observe the thermo-mechanical interactive behaviour of the concrete and rock at several levels, in both rock and concrete. A thermo-mechanical fracture mechanics study is necessary for the prediction of the damage before the experiment, in order to plan the experiment and instrumentation, and for generating a proper prediction/outcome study due to the special nature of the in situ experiment. The prediction of acoustic emission patterns is made by Fracod 2D and the model later compared to the actual observed acoustic emissions. The fracture mechanics model will be compared to a COMSOL Multiphysics 3D model to study the geometrical effects along the hole axis.

  4. Innovative Fresh Water Production Process for Fossil Fuel Plants

    SciTech Connect

    James F. Klausner; Renwei Mei; Yi Li; Jessica Knight

    2006-09-29

    This project concerns a diffusion driven desalination (DDD) process where warm water is evaporated into a low humidity air stream, and the vapor is condensed out to produce distilled water. Although the process has a low fresh water to feed water conversion efficiency, it has been demonstrated that this process can potentially produce low cost distilled water when driven by low grade waste heat. This report summarizes the progress made in the development and analysis of a Diffusion Driven Desalination (DDD) system. Detailed heat and mass transfer analyses required to size and analyze the diffusion tower using a heated water input are described. The analyses agree quite well with the current data and the information available in the literature. The direct contact condenser has also been thoroughly analyzed and the system performance at optimal operating conditions has been considered using a heated water/ambient air input to the diffusion tower. The diffusion tower has also been analyzed using a heated air input. The DDD laboratory facility has successfully been modified to include an air heating section. Experiments have been conducted over a range of parameters for two different cases: heated air/heated water and heated air/ambient water. A theoretical heat and mass transfer model has been examined for both of these cases and agreement between the experimental and theoretical data is good. A parametric study reveals that for every liquid mass flux there is an air mass flux value where the diffusion tower energy consumption is minimal and an air mass flux where the fresh water production flux is maximized. A study was also performed to compare the DDD process with different inlet operating conditions as well as different packing. It is shown that the heated air/heated water case is more capable of greater fresh water production with the same energy consumption than the ambient air/heated water process at high liquid mass flux. It is also shown that there can be

  5. Integrated modeling of LHCD experiment on Alcator C-Mod

    SciTech Connect

    Shiraiwa, S.; Bonoli, P.; Parker, R.; Wallace, G.

    2014-02-12

    Recent progress in integrating the latest LHCD model based on ray-tracing into the Integrated Plasma Simulator (IPS) is reported. IPS, a python based framework for time dependent tokamak simulation, was expanded recently to incorporate LHCD simulation using GENRAY/CQL3D (ray-tracing/3D Fokker-Planck package). Using GENRAY/CQL3D in the IPS framework, it becomes possible to include parasitic LHCD power loss near the plasma edge, which was found to be important in experiments particularly at high density as expected on reactors. Moreover, it allows for evolving the velocity distribution function in 4 D (ν{sub ∥}, ν⊥, r/a, t) space self-consistently. In order to validate the code, IPS is applied to LHCD experiments on Alctor C-Mod. In this paper, a LHCD experiment performed at the density of n{sub e}∼0.5×10{sup 20}m{sup −3} where good LHCD efficiency and the development of internal transport barrier (ITB) was reported, is modelled in a predictive mode and the result is compared with experiment.

  6. Danish heathland manipulation experiment data in Model-Data-Fusion

    NASA Astrophysics Data System (ADS)

    Thum, Tea; Peylin, Philippe; Ibrom, Andreas; Van Der Linden, Leon; Beier, Claus; Bacour, Cédric; Santaren, Diego; Ciais, Philippe

    2013-04-01

    In ecosystem manipulation experiments (EMEs) the ecosystem is artificially exposed to different environmental conditions that aim to simulate circumstances in future climate. At Danish EME site Brandbjerg the responses of a heathland to drought, warming and increased atmospheric CO2 concentration are studied. The warming manipulation is realized by passive nighttime warming. The measurements include control plots as well as replicates for each three treatment separately and in combination. The Brandbjerg heathland ecosystem is dominated by heather and wavy hairgrass. These experiments provide excellent data for validation and development of ecosystem models. In this work we used a generic vegetation model ORCHIDEE with Model-Data-Fusion (MDF) approach. ORCHIDEE model is a process-based model that describes the exchanges of carbon, water and energy between the atmosphere and the vegetation. It can be run at different spatial scales from global to site level. Different vegetation types are described in ORCHIDEE as plant functional types. In MDF we are using observations from the site to optimize the model parameters. This enables us to assess the modelling errors and the performance of the model for different manipulation treatments. This insight will inform us whether the different processes are adequately modelled or if the model is missing some important processes. We used a genetic algorithm in the MDF. The data available from the site included measurements of aboveground biomass, heterotrophic soil respiration and total ecosystem respiration from years 2006-2008. The biomass was measured six times doing this period. The respiration measurements were done with manual chamber measurements. For the soil respiration we used results from an empirical model that has been developed for the site. This enabled us to have more data for the MDF. Before the MDF we performed a sensitivity analysis of the model parameters to different data streams. Fifteen most influential

  7. Generating a soliton splash through variational modelling and experiments

    NASA Astrophysics Data System (ADS)

    Kalogirou, Anna; Bokhove, Onno

    2015-11-01

    Mathematical modelling of water waves in tanks with wave generators is demonstrated by investigating variational methods asymptotically and numerically. A reduced potential flow water wave model is derived using variational techniques, which is based on the assumptions of waves with small amplitude and large wavelength. This model consists of a set of modified Benney-Luke equations describing the deviation from the still water surface η (x , y , t) and the bottom potential Φ (x , y , t) , and includes a time-dependent gravitional potential mimicking a removable ``sluice gate''. The asymptotic model is solved numerically using the automated system Firedrake. In particular, a (dis)continuous Galerkin finite element method is used, together with symplectic integrators for the time discretisation. As a validation, the numerical results are compared to a soliton splash experiment in a long water channel with a contraction at its end, resulting after a sluice gate is removed at a finite time.

  8. Experience in calibrating the double-hardening constitutive model Monot

    NASA Astrophysics Data System (ADS)

    Hicks, M. A.

    2003-11-01

    The Monot double-hardening soil model has previously been implemented within a general purpose finite element algorithm, and used in the analysis of numerous practical problems. This paper reviews experience gained in calibrating Monot to laboratory data and demonstrates how the calibration process may be simplified without detriment to the range of behaviours modelled. It describes Monot's principal features, important governing equations and various calibration methods, including strategies for overconsolidated, cemented and cohesive soils. Based on a critical review of over 30 previous Monot calibrations, for sands and other geomaterials, trends in parameter values have been identified, enabling parameters to be categorized according to their relative importance. It is shown that, for most practical purposes, a maximum of only 5 parameters is needed; for the remaining parameters, standard default values are suggested. Hence, the advanced stress-strain modelling offered by Monot is attainable with a similar number of parameters as would be needed for some simpler, less versatile, models. Copyright

  9. Testing a model of aging in animal experiments.

    PubMed

    Tyurin YuN; Yakovlev AYu; Shi, J; Bass, L

    1995-03-01

    A stochastic model of aging is developed in terms of accumulation and expression of intracellular lesions caused by environment or intrinsic genetic program. In contrast to the commonly used Gompertz-Makeham approach to the parametric analysis of mortality data, the model yields a hazard function that is bounded from above. For testing the model in experiments aimed at studying animal longevity, a Kolmogorov-type statistical test is presented with regard to the hypothesis involving unknown parameters. Examples concerning longevity of intact animals of two different species, as well as the effect of a prolonged irradiation at a low dose rate, are given to illustrate the model application and goodness-of-fit testing. The results of the analysis of published data show that the rate of lesion formation is not sustained at a constant level throughout life, though in some cases its variations with age can be considered negligible. PMID:7766791

  10. Early experiences building a software quality prediction model

    NASA Technical Reports Server (NTRS)

    Agresti, W. W.; Evanco, W. M.; Smith, M. C.

    1990-01-01

    Early experiences building a software quality prediction model are discussed. The overall research objective is to establish a capability to project a software system's quality from an analysis of its design. The technical approach is to build multivariate models for estimating reliability and maintainability. Data from 21 Ada subsystems were analyzed to test hypotheses about various design structures leading to failure-prone or unmaintainable systems. Current design variables highlight the interconnectivity and visibility of compilation units. Other model variables provide for the effects of reusability and software changes. Reported results are preliminary because additional project data is being obtained and new hypotheses are being developed and tested. Current multivariate regression models are encouraging, explaining 60 to 80 percent of the variation in error density of the subsystems.

  11. Numerical modeling of injection experiments at The Geysers

    SciTech Connect

    Pruess, Karsten; Enedy, Steve

    1993-01-28

    Data from injection experiments in the southeast Geysers are presented that show strong interference (both negative and positive) with a neighboring production well. Conceptual and numerical models are developed that explain the negative interference (decline of production rate) in terms of heat transfer limitations and water-vapor relative permeability effects. Recovery and overrecovery following injection shut-in are attributed to boiling of injected fluid, with heat of vaporization provided by the reservoir rocks.

  12. Explanatory Models and Illness Experience of People Living with HIV.

    PubMed

    Laws, M Barton

    2016-09-01

    Research into explanatory models of disease and illness typically explores people's conceptual understanding, and emphasizes differences between patient and provider models. However, the explanatory models framework of etiology, time and mode of onset of symptoms, pathophysiology, course of sickness, and treatment is built on categories characteristic of biomedical understanding. It is unclear how well these map onto people's lived experience of illness, and to the extent they do, how they translate. Scholars have previously studied the experience of people living with HIV through the lenses of stigma and identity theory. Here, through in-depth qualitative interviews with 32 people living with HIV in the northeast United States, we explored the experience and meanings of living with HIV more broadly using the explanatory models framework. We found that identity reformation is a major challenge for most people following the HIV diagnosis, and can be understood as a central component of the concept of course of illness. Salient etiological explanations are not biological, but rather social, such as betrayal, or living in a specific cultural milieu, and often self-evaluative. Given that symptoms can now largely be avoided through adherence to treatment, they are most frequently described in terms of observation of others who have not been adherent, or the resolution of symptoms following treatment. The category of pathophysiology is not ordinarily very relevant to the illness experience, as few respondents have any understanding of the mechanism of pathogenesis in HIV, nor much interest in it. Treatment has various personal meanings, both positive and negative, often profound. For people to engage successfully in treatment and live successfully with HIV, mechanistic explanation is of little significance. Rather, positive psychological integration of health promoting behaviors is of central importance. PMID:26971285

  13. Experiments and modelling of coal pyrolysis under fluidized bed conditions

    NASA Astrophysics Data System (ADS)

    Zhang, Yongzhe; Xu, Xiangdong; Zuo, Yu

    1999-09-01

    The pyrolysis behavior of two Chinese coals has been investigated in a laboratory-scale bubbling fluidized bed system in Siegen University, Germany. Experimental equipment and procedure are introduced. The amounts of pyrolysis species of each coal were measured, calculated and compared. A new method was presented to determine the needed parameters in FG-DVC model with the experimental results instead of other much more complicated experiments.

  14. Numerical modeling of injection experiments at The Geysers

    SciTech Connect

    Pruess, K. ); Enedy, S. )

    1993-01-01

    Data from injection experiments in the southeast Geysers are presented that show strong interference (both negative and positive) with a neighboring production well. Conceptual and numerical models are developed that explain the negative interference (decline of production rate) in terms of heat transfer limitations and water-vapor relative permeability effects. Recovery and over-recovery following injection shut-in are attributed to boiling of injected fluid, with heat of vaporization provided by the reservoir rocks.

  15. Analogue experiments as benchmarks for models of lava flow emplacement

    NASA Astrophysics Data System (ADS)

    Garel, F.; Kaminski, E. C.; Tait, S.; Limare, A.

    2013-12-01

    During an effusive volcanic eruption, the crisis management is mainly based on the prediction of lava flow advance and its velocity. The spreading of a lava flow, seen as a gravity current, depends on its "effective rheology" and on the effusion rate. Fast-computing models have arisen in the past decade in order to predict in near real time lava flow path and rate of advance. This type of model, crucial to mitigate volcanic hazards and organize potential evacuation, has been mainly compared a posteriori to real cases of emplaced lava flows. The input parameters of such simulations applied to natural eruptions, especially effusion rate and topography, are often not known precisely, and are difficult to evaluate after the eruption. It is therefore not straightforward to identify the causes of discrepancies between model outputs and observed lava emplacement, whereas the comparison of models with controlled laboratory experiments appears easier. The challenge for numerical simulations of lava flow emplacement is to model the simultaneous advance and thermal structure of viscous lava flows. To provide original constraints later to be used in benchmark numerical simulations, we have performed lab-scale experiments investigating the cooling of isoviscous gravity currents. The simplest experimental set-up is as follows: silicone oil, whose viscosity, around 5 Pa.s, varies less than a factor of 2 in the temperature range studied, is injected from a point source onto a horizontal plate and spreads axisymmetrically. The oil is injected hot, and progressively cools down to ambient temperature away from the source. Once the flow is developed, it presents a stationary radial thermal structure whose characteristics depend on the input flow rate. In addition to the experimental observations, we have developed in Garel et al., JGR, 2012 a theoretical model confirming the relationship between supply rate, flow advance and stationary surface thermal structure. We also provide

  16. An energetic model for macromolecules unfolding in stretching experiments

    PubMed Central

    De Tommasi, D.; Millardi, N.; Puglisi, G.; Saccomandi, G.

    2013-01-01

    We propose a simple approach, based on the minimization of the total (entropic plus unfolding) energy of a two-state system, to describe the unfolding of multi-domain macromolecules (proteins, silks, polysaccharides, nanopolymers). The model is fully analytical and enlightens the role of the different energetic components regulating the unfolding evolution. As an explicit example, we compare the analytical results with a titin atomic force microscopy stretch-induced unfolding experiment showing the ability of the model to quantitatively reproduce the experimental behaviour. In the thermodynamic limit, the sawtooth force–elongation unfolding curve degenerates to a constant force unfolding plateau. PMID:24047874

  17. Richtmyer-Meshkov mixing: Modeling and simulation of experiments

    NASA Astrophysics Data System (ADS)

    Denissen, Nicholas; Kurien, Susan

    2015-11-01

    Hydrodynamic instabilities that result from the interaction of a shock-wave with a perturbed interface are known as Richtmyer-Meshkov instabilities (RMI). RMI is important in a wide variety of applications including Inertial Confinement Fusion. Recent experiments at Los Alamos National Laboratory (LANL) have focused on careful measurement of initial conditions and repeated statistical measurements of the instability growth and transition to turbulence. This talk will discuss ongoing efforts to model these experiments using weakly non-linear theoretical models, one dimensional Reynolds-Averaged Navier-Stokes models and three-dimensional Implicit Large Eddy Simulations (ILES). Analysis of the experimental data supplies the initial condition for the theoretical model and the ILES calculations. The effect of different initial conditions and mesh resolutions will be examined in light of interest in international collaboration on an RMI test problem. Comparison of the different models to experimental data will be presented. All calculations are performed in the arbitrary Lagrangian/Eulerian (ALE) code FLAG, developed at LANL. The ALE framework allows us to assess the effects of numerical diffusion on RMI computations by varying the remap strategy.

  18. Design and MHD modeling of ATLAS experiments to study friction

    SciTech Connect

    Faehl, R. J.; Hammerberg, J. E.

    2002-01-01

    Transverse shear at the interface of two solids occurs when these solids move at different velocities. This frictional phenomenon is being studied in a series of experiments on the ATLAS capacitor bank at Los Alamos. Cylindrical targets to test friction force models are composed of alternating regions of high- and low-shock speed materials. When the target is impacted by a cylindrical, magnetically-accelerated aluminum liner, the differential shock velocity in the two materials establishes the desired shear at the interface. One- and two-dimensional MHD calculations have been performed to design liners with suitable properties to drive these 'friction-like' ATLAS experiments. A thick impactor allows the shock to be maintained for several microseconds. The ATLAS experiments use a liner that is approximately 10 mm thick at impact, with an inner surface velocity of {approx} 1.4-1.5 km/s. Interaction of this thick liner with the electrodes, or glide planes, results in significant deformation of the hardened stainless steel electrodes. Data from the ATLAS experiments and comparisons with the calculations will be presented, along with plans for future experiments.

  19. Toward an Improved Understanding of the Global Fresh Water Budget

    NASA Technical Reports Server (NTRS)

    Hildebrand, Peter H.

    2005-01-01

    The major components of the global fresh water cycle include the evaporation from the land and ocean surfaces, precipitation onto the Ocean and land surfaces, the net atmospheric transport of water from oceanic areas over land, and the return flow of water from the land back into the ocean. The additional components of oceanic water transport are few, principally, the mixing of fresh water through the oceanic boundary layer, transport by ocean currents, and sea ice processes. On land the situation is considerably more complex, and includes the deposition of rain and snow on land; water flow in runoff; infiltration of water into the soil and groundwater; storage of water in soil, lakes and streams, and groundwater; polar and glacial ice; and use of water in vegetation and human activities. Knowledge of the key terms in the fresh water flux budget is poor. Some components of the budget, e.g. precipitation, runoff, storage, are measured with variable accuracy across the globe. We are just now obtaining precise measurements of the major components of global fresh water storage in global ice and ground water. The easily accessible fresh water sources in rivers, lakes and snow runoff are only adequately measured in the more affluent portions of the world. presents proposals are suggesting methods of making global measurements of these quantities from space. At the same time, knowledge of the global fresh water resources under the effects of climate change is of increasing importance and the human population grows. This paper provides an overview of the state of knowledge of the global fresh water budget, evaluating the accuracy of various global water budget measuring and modeling techniques. We review the measurement capabilities of satellite instruments as compared with field validation studies and modeling approaches. Based on these analyses, and on the goal of improved knowledge of the global fresh water budget under the effects of climate change, we suggest

  20. Experiments and Computational Modeling of Pulverized-Clak Ignition.

    SciTech Connect

    Chen, J.C.

    1997-08-01

    Under typical conditions of pulverized-coal combustion, which is characterized by fine particles heated at very high rates, there is currently a lack of certainty regarding the ignition mechanism of bituminous and lower rank coals. It is unclear whether ignition occurs first at the particle-oxygen interface (heterogeneous ignition) or if it occurs in the gas phase due to ignition of the devolatilization products (homogeneous ignition). Furthermore, there have been no previous studies aimed at determining the dependence of the ignition mechanism on variations in experimental conditions, such as particle size, oxygen concentration, and heating rate. Finally, there is a need to improve current mathematical models of ignition to realistically and accurately depict the particle-to-particle variations that exist within a coal sample. Such a model is needed to extract useful reaction parameters from ignition studies, and to interpret ignition data in a more meaningful way. We propose to examine fundamental aspects of coal ignition through (1) experiments to determine the ignition mechanism of various coals by direct observation, and (2) modeling of the ignition process to derive rate constants and to provide a more insightful interpretation of data from ignition experiments. We propose to use a novel laser-based ignition experiment to achieve our objectives.

  1. Modeling of high power ICRF heating experiments on TFTR

    SciTech Connect

    Phillips, C.K.; Wilson, J.R.; Bell, M.; Fredrickson, E.; Hosea, J.C.; Majeski, R.; Ramsey, A.; Rogers, J.H.; Schilling, G.; Skinner, C.; Stevens, J.E.; Taylor, G.; Wong, K.L.; Khudaleev, A.; Petrov, M.P.; Murakami, M.

    1993-04-01

    Over the past two years, ICRF heating experiments have been performed on TFTR in the hydrogen minority heating regime with power levels reaching 11.2 MW in helium-4 majority plasmas and 8.4 MW in deuterium majority plasmas. For these power levels, the minority hydrogen ions, which comprise typically less than 10% of the total electron density, evolve into la very energetic, anisotropic non-Maxwellian distribution. Indeed, the excess perpendicular stored energy in these plasmas associated with the energetic minority tail ions is often as high as 25% of the total stored energy, as inferred from magnetic measurements. Enhanced losses of 0.5 MeV protons consistent with the presence of an energetic hydrogen component have also been observed. In ICRF heating experiments on JET at comparable and higher power levels and with similar parameters, it has been suggested that finite banana width effects have a noticeable effect on the ICRF power deposition. In particular, models indicate that finite orbit width effects lead to a reduction in the total stored energy and of the tail energy in the center of the plasma, relative to that predicted by the zero banana width models. In this paper, detailed comparisons between the calculated ICRF power deposition profiles and experimentally measured quantities will be presented which indicate that significant deviations from the zero banana width models occur even for modest power levels (P{sub rf} {approximately} 6 MW) in the TFTR experiments.

  2. Modeling of high power ICRF heating experiments on TFTR

    SciTech Connect

    Phillips, C.K.; Wilson, J.R.; Bell, M.; Fredrickson, E.; Hosea, J.C.; Majeski, R.; Ramsey, A.; Rogers, J.H.; Schilling, G.; Skinner, C.; Stevens, J.E.; Taylor, G.; Wong, K.L. . Plasma Physics Lab.); Khudaleev, A.; Petrov, M.P. ); Murakami, M. )

    1993-01-01

    Over the past two years, ICRF heating experiments have been performed on TFTR in the hydrogen minority heating regime with power levels reaching 11.2 MW in helium-4 majority plasmas and 8.4 MW in deuterium majority plasmas. For these power levels, the minority hydrogen ions, which comprise typically less than 10% of the total electron density, evolve into la very energetic, anisotropic non-Maxwellian distribution. Indeed, the excess perpendicular stored energy in these plasmas associated with the energetic minority tail ions is often as high as 25% of the total stored energy, as inferred from magnetic measurements. Enhanced losses of 0.5 MeV protons consistent with the presence of an energetic hydrogen component have also been observed. In ICRF heating experiments on JET at comparable and higher power levels and with similar parameters, it has been suggested that finite banana width effects have a noticeable effect on the ICRF power deposition. In particular, models indicate that finite orbit width effects lead to a reduction in the total stored energy and of the tail energy in the center of the plasma, relative to that predicted by the zero banana width models. In this paper, detailed comparisons between the calculated ICRF power deposition profiles and experimentally measured quantities will be presented which indicate that significant deviations from the zero banana width models occur even for modest power levels (P[sub rf] [approximately] 6 MW) in the TFTR experiments.

  3. The Dependent Poisson Race Model and Modeling Dependence in Conjoint Choice Experiments

    ERIC Educational Resources Information Center

    Ruan, Shiling; MacEachern, Steven N.; Otter, Thomas; Dean, Angela M.

    2008-01-01

    Conjoint choice experiments are used widely in marketing to study consumer preferences amongst alternative products. We develop a class of choice models, belonging to the class of Poisson race models, that describe a "random utility" which lends itself to a process-based description of choice. The models incorporate a dependence structure which…

  4. Synergy of fresh and accumulated organic matter to bacterial growth.

    PubMed

    Farjalla, Vinicius F; Marinho, Claudio C; Faria, Bias M; Amado, André M; Esteves, Francisco de A; Bozelli, Reinaldo L; Giroldo, Danilo

    2009-05-01

    The main goal of this research was to evaluate whether the mixture of fresh labile dissolved organic matter (DOM) and accumulated refractory DOM influences bacterial production, respiration, and growth efficiency (BGE) in aquatic ecosystems. Bacterial batch cultures were set up using DOM leached from aquatic macrophytes as the fresh DOM pool and DOM accumulated from a tropical humic lagoon. Two sets of experiments were performed and bacterial growth was followed in cultures composed of each carbon substrate (first experiment) and by carbon substrates combined (second experiment), with and without the addition of nitrogen and phosphorus. In both experiments, bacterial production, respiration, and BGE were always higher in cultures with N and P additions, indicating a consistent inorganic nutrient limitation. Bacterial production, respiration, and BGE were higher in cultures set up with leachate DOM than in cultures set up with humic DOM, indicating that the quality of the organic matter pool influenced the bacterial growth. Bacterial production and respiration were higher in the mixture of substrates (second experiment) than expected by bacterial production and respiration in single substrate cultures (first experiment). We suggest that the differences in the concentration of some compounds between DOM sources, the co-metabolism on carbon compound decomposition, and the higher diversity of molecules possibly support a greater bacterial diversity which might explain the higher bacterial growth observed. Finally, our results indicate that the mixture of fresh labile and accumulated refractory DOM that naturally occurs in aquatic ecosystems could accelerate the bacterial growth and bacterial DOM removal. PMID:18985269

  5. Ontological and Epistemological Issues Regarding Climate Models and Computer Experiments

    NASA Astrophysics Data System (ADS)

    Vezer, M. A.

    2010-12-01

    Recent philosophical discussions (Parker 2009; Frigg and Reiss 2009; Winsberg, 2009; Morgon 2002, 2003, 2005; Gula 2002) about the ontology of computer simulation experiments and the epistemology of inferences drawn from them are of particular relevance to climate science as computer modeling and analysis are instrumental in understanding climatic systems. How do computer simulation experiments compare with traditional experiments? Is there an ontological difference between these two methods of inquiry? Are there epistemological considerations that result in one type of inference being more reliable than the other? What are the implications of these questions with respect to climate studies that rely on computer simulation analysis? In this paper, I examine these philosophical questions within the context of climate science, instantiating concerns in the philosophical literature with examples found in analysis of global climate change. I concentrate on Wendy Parker’s (2009) account of computer simulation studies, which offers a treatment of these and other questions relevant to investigations of climate change involving such modelling. Two theses at the center of Parker’s account will be the focus of this paper. The first is that computer simulation experiments ought to be regarded as straightforward material experiments; which is to say, there is no significant ontological difference between computer and traditional experimentation. Parker’s second thesis is that some of the emphasis on the epistemological importance of materiality has been misplaced. I examine both of these claims. First, I inquire as to whether viewing computer and traditional experiments as ontologically similar in the way she does implies that there is no proper distinction between abstract experiments (such as ‘thought experiments’ as well as computer experiments) and traditional ‘concrete’ ones. Second, I examine the notion of materiality (i.e., the material commonality between

  6. Opinion Formation by Social Influence: From Experiments to Modeling

    PubMed Central

    Chacoma, Andrés; Zanette, Damián H.

    2015-01-01

    Predicting different forms of collective behavior in human populations, as the outcome of individual attitudes and their mutual influence, is a question of major interest in social sciences. In particular, processes of opinion formation have been theoretically modeled on the basis of a formal similarity with the dynamics of certain physical systems, giving rise to an extensive collection of mathematical models amenable to numerical simulation or even to exact solution. Empirical ground for these models is however largely missing, which confine them to the level of mere metaphors of the real phenomena they aim at explaining. In this paper we present results of an experiment which quantifies the change in the opinions given by a subject on a set of specific matters under the influence of others. The setup is a variant of a recently proposed experiment, where the subject’s confidence on his or her opinion was evaluated as well. In our realization, which records the quantitative answers of 85 subjects to 20 questions before and after an influence event, the focus is put on characterizing the change in answers and confidence induced by such influence. Similarities and differences with the previous version of the experiment are highlighted. We find that confidence changes are to a large extent independent of any other recorded quantity, while opinion changes are strongly modulated by the original confidence. On the other hand, opinion changes are not influenced by the initial difference with the reference opinion. The typical time scales on which opinion varies are moreover substantially longer than those of confidence change. Experimental results are then used to estimate parameters for a dynamical agent-based model of opinion formation in a large population. In the context of the model, we study the convergence to full consensus and the effect of opinion leaders on the collective distribution of opinions. PMID:26517825

  7. Historical and idealized climate model experiments: an EMIC intercomparison

    NASA Astrophysics Data System (ADS)

    Eby, M.; Weaver, A. J.; Alexander, K.; Zickfeld, K.; Abe-Ouchi, A.; Cimatoribus, A. A.; Crespin, E.; Drijfhout, S. S.; Edwards, N. R.; Eliseev, A. V.; Feulner, G.; Fichefet, T.; Forest, C. E.; Goosse, H.; Holden, P. B.; Joos, F.; Kawamiya, M.; Kicklighter, D.; Kienert, H.; Matsumoto, K.; Mokhov, I. I.; Monier, E.; Olsen, S. M.; Pedersen, J. O. P.; Perrette, M.; Philippon-Berthier, G.; Ridgwell, A.; Schlosser, A.; Schneider von Deimling, T.; Shaffer, G.; Smith, R. S.; Spahni, R.; Sokolov, A. P.; Steinacher, M.; Tachiiri, K.; Tokos, K.; Yoshimori, M.; Zeng, N.; Zhao, F.

    2012-08-01

    Both historical and idealized climate model experiments are performed with a variety of Earth System Models of Intermediate Complexity (EMICs) as part of a community contribution to the Intergovernmental Panel on Climate Change Fifth Assessment Report. Historical simulations start at 850 CE and continue through to 2005. The standard simulations include changes in forcing from solar luminosity, Earth's orbital configuration, CO2, additional greenhouse gases, land-use, and sulphate and volcanic aerosols. In spite of very different modelled pre-industrial global surface air temperatures, overall 20th century trends in surface air temperature and carbon uptake are reasonably well simulated when compared to observed trends. Land carbon fluxes show much more variation between models than ocean carbon fluxes, and recent land fluxes seem to be underestimated. It is possible that recent modelled climate trends or climate-carbon feedbacks are overestimated resulting in too much land carbon loss or that carbon uptake due to CO2 and/or nitrogen fertilization is underestimated. Several one thousand year long, idealized, 2x and 4x CO2 experiments are used to quantify standard model characteristics, including transient and equilibrium climate sensitivities, and climate-carbon feedbacks. The values from EMICs generally fall within the range given by General Circulation Models. Seven additional historical simulations, each including a single specified forcing, are used to assess the contributions of different climate forcings to the overall climate and carbon cycle response. The response of surface air temperature is the linear sum of the individual forcings, while the carbon cycle response shows considerable synergy between land-use change and CO2 forcings for some models. Finally, the preindustrial portions of the last millennium simulations are used to assess historical model carbon-climate feedbacks. Given the specified forcing, there is a tendency for the EMICs to

  8. Multi-injector modeling of transverse combustion instability experiments

    NASA Astrophysics Data System (ADS)

    Shipley, Kevin J.

    Concurrent simulations and experiments are used to study combustion instabilities in a multiple injector element combustion chamber. The experiments employ a linear array of seven coaxial injector elements positioned atop a rectangular chamber. Different levels of instability are driven in the combustor by varying the operating and geometry parameters of the outer driving injector elements located near the chamber end-walls. The objectives of the study are to apply a reduced three-injector model to generate a computational test bed for the evaluation of injector response to transverse instability, to apply a full seven-injector model to investigate the inter-element coupling between injectors in response to transverse instability, and to further develop this integrated approach as a key element in a predictive methodology that relies heavily on subscale test and simulation. To measure the effects of the transverse wave on a central study injector element two opposing windows are placed in the chamber to allow optical access. The chamber is extensively instrumented with high-frequency pressure transducers. High-fidelity computational fluid dynamics simulations are used to model the experiment. Specifically three-dimensional, detached eddy simulations (DES) are used. Two computational approaches are investigated. The first approach models the combustor with three center injectors and forces transverse waves in the chamber with a wall velocity function at the chamber side walls. Different levels of pressure oscillation amplitudes are possible by varying the amplitude of the forcing function. The purpose of this method is to focus on the combustion response of the study element. In the second approach, all seven injectors are modeled and self-excited combustion instability is achieved. This realistic model of the chamber allows the study of inter-element flow dynamics, e.g., how the resonant motions in the injector tubes are coupled through the transverse pressure

  9. RANS Modeling of Benchmark Shockwave / Boundary Layer Interaction Experiments

    NASA Technical Reports Server (NTRS)

    Georgiadis, Nick; Vyas, Manan; Yoder, Dennis

    2010-01-01

    This presentation summarizes the computations of a set of shock wave / turbulent boundary layer interaction (SWTBLI) test cases using the Wind-US code, as part of the 2010 American Institute of Aeronautics and Astronautics (AIAA) shock / boundary layer interaction workshop. The experiments involve supersonic flows in wind tunnels with a shock generator that directs an oblique shock wave toward the boundary layer along one of the walls of the wind tunnel. The Wind-US calculations utilized structured grid computations performed in Reynolds-averaged Navier-Stokes mode. Three turbulence models were investigated: the Spalart-Allmaras one-equation model, the Menter Shear Stress Transport wavenumber-angular frequency two-equation model, and an explicit algebraic stress wavenumber-angular frequency formulation. Effects of grid resolution and upwinding scheme were also considered. The results from the CFD calculations are compared to particle image velocimetry (PIV) data from the experiments. As expected, turbulence model effects dominated the accuracy of the solutions with upwinding scheme selection indicating minimal effects.!

  10. Exploration in free word association networks: models and experiment.

    PubMed

    Ludueña, Guillermo A; Behzad, Mehran Djalali; Gros, Claudius

    2014-05-01

    Free association is a task that requires a subject to express the first word to come to their mind when presented with a certain cue. It is a task which can be used to expose the basic mechanisms by which humans connect memories. In this work, we have made use of a publicly available database of free associations to model the exploration of the averaged network of associations using a statistical and the adaptive control of thought-rational (ACT-R) model. We performed, in addition, an online experiment asking participants to navigate the averaged network using their individual preferences for word associations. We have investigated the statistics of word repetitions in this guided association task. We find that the considered models mimic some of the statistical properties, viz the probability of word repetitions, the distance between repetitions and the distribution of association chain lengths, of the experiment, with the ACT-R model showing a particularly good fit to the experimental data for the more intricate properties as, for instance, the ratio of repetitions per length of association chains. PMID:24264368

  11. Hyperspectral imaging technique for determination of pork freshness attributes

    NASA Astrophysics Data System (ADS)

    Li, Yongyu; Zhang, Leilei; Peng, Yankun; Tang, Xiuying; Chao, Kuanglin; Dhakal, Sagar

    2011-06-01

    Freshness of pork is an important quality attribute, which can vary greatly in storage and logistics. The specific objectives of this research were to develop a hyperspectral imaging system to predict pork freshness based on quality attributes such as total volatile basic-nitrogen (TVB-N), pH value and color parameters (L*,a*,b*). Pork samples were packed in seal plastic bags and then stored at 4°C. Every 12 hours. Hyperspectral scattering images were collected from the pork surface at the range of 400 nm to 1100 nm. Two different methods were performed to extract scattering feature spectra from the hyperspectral scattering images. First, the spectral scattering profiles at individual wavelengths were fitted accurately by a three-parameter Lorentzian distribution (LD) function; second, reflectance spectra were extracted from the scattering images. Partial Least Square Regression (PLSR) method was used to establish prediction models to predict pork freshness. The results showed that the PLSR models based on reflectance spectra was better than combinations of LD "parameter spectra" in prediction of TVB-N with a correlation coefficient (r) = 0.90, a standard error of prediction (SEP) = 7.80 mg/100g. Moreover, a prediction model for pork freshness was established by using a combination of TVB-N, pH and color parameters. It could give a good prediction results with r = 0.91 for pork freshness. The research demonstrated that hyperspectral scattering technique is a valid tool for real-time and nondestructive detection of pork freshness.

  12. Integrated Experiment and Modeling of Insensitive High Explosives

    NASA Astrophysics Data System (ADS)

    Stewart, D. Scott; Lambert, David E.; Yoo, Sunhee; Lieber, Mark; Holman, Steven

    2009-12-01

    New design paradigms for insensitive high explosives are being sought for use in munitions applications that require enhanced safety, reliability and performance. We describe recent work of our group that uses an integrated approach to develop predictive models, guided by experiments. Insensitive explosive can have relatively longer detonation reaction zones and slower reaction rates than their sensitive counterparts. We employ reactive flow models that are constrained by detonation shock dynamics (DSD) to pose candidate predictive models. We discuss the variation of the pressure dependent reaction rate exponent and reaction order on the length of the supporting reaction zone, the detonation velocity curvature relation, the computed critical energy required for initiation, the relation between the diameter effect curve and the corresponding normal detonation velocity curvature relation.

  13. '23 h Model' for breast surgery: an early experience.

    PubMed

    Hainsworth, A J; Lobo, C R; Williams, P; Case, C; Surridge, F; Sharma, A K; Banerjee, D

    2013-10-01

    The principles of fast track surgery are well established in colorectal surgery. It is an evidence based model aimed at reducing length of stay, convalescence and morbidity by optimising both clinical and organisational factors. Despite this, the implementation of fast track surgery in breast cancer patients has been slow. The 23 h discharge model for breast cancer surgery patients has been outlined by the NHS Improvement Programme and is a breakthrough from traditional inpatient care. This paper outlines the early experience of implementation of this model in a single institution during a 3-month audit period. Over 80% of patients undergoing non-reconstructive breast surgery were discharged safely within '23 h'. This suggests that good communication links, reorganisation of existing resources, active user involvement (both patients and clinical team) and strong project management ensures fast-tracking to be safe for the patient with significant economic benefits for the hospital. PMID:23664255

  14. Beyond Performance: A Motivational Experiences Model of Stereotype Threat

    PubMed Central

    Thoman, Dustin B.; Smith, Jessi L.; Brown, Elizabeth R.; Chase, Justin; Lee, Joo Young K.

    2013-01-01

    The contributing role of stereotype threat (ST) to learning and performance decrements for stigmatized students in highly evaluative situations has been vastly documented and is now widely known by educators and policy makers. However, recent research illustrates that underrepresented and stigmatized students’ academic and career motivations are influenced by ST more broadly, particularly through influences on achievement orientations, sense of belonging, and intrinsic motivation. Such a focus moves conceptualizations of ST effects in education beyond the influence on a student’s performance, skill level, and feelings of self-efficacy per se to experiencing greater belonging uncertainty and lower interest in stereotyped tasks and domains. These negative experiences are associated with important outcomes such as decreased persistence and domain identification, even among students who are high in achievement motivation. In this vein, we present and review support for the Motivational Experience Model of ST, a self-regulatory model framework for integrating research on ST, achievement goals, sense of belonging, and intrinsic motivation to make predictions for how stigmatized students’ motivational experiences are maintained or disrupted, particularly over long periods of time. PMID:23894223

  15. Multi-scale modelling for HEDP experiments on Orion

    NASA Astrophysics Data System (ADS)

    Sircombe, N. J.; Ramsay, M. G.; Hughes, S. J.; Hoarty, D. J.

    2016-05-01

    The Orion laser at AWE couples high energy long-pulse lasers with high intensity short-pulses, allowing material to be compressed beyond solid density and heated isochorically. This experimental capability has been demonstrated as a platform for conducting High Energy Density Physics material properties experiments. A clear understanding of the physics in experiments at this scale, combined with a robust, flexible and predictive modelling capability, is an important step towards more complex experimental platforms and ICF schemes which rely on high power lasers to achieve ignition. These experiments present a significant modelling challenge, the system is characterised by hydrodynamic effects over nanoseconds, driven by long-pulse lasers or the pre-pulse of the petawatt beams, and fast electron generation, transport, and heating effects over picoseconds, driven by short-pulse high intensity lasers. We describe the approach taken at AWE; to integrate a number of codes which capture the detailed physics for each spatial and temporal scale. Simulations of the heating of buried aluminium microdot targets are discussed and we consider the role such tools can play in understanding the impact of changes to the laser parameters, such as frequency and pre-pulse, as well as understanding effects which are difficult to observe experimentally.

  16. Beyond Performance: A Motivational Experiences Model of Stereotype Threat.

    PubMed

    Thoman, Dustin B; Smith, Jessi L; Brown, Elizabeth R; Chase, Justin; Lee, Joo Young K

    2013-06-01

    The contributing role of stereotype threat (ST) to learning and performance decrements for stigmatized students in highly evaluative situations has been vastly documented and is now widely known by educators and policy makers. However, recent research illustrates that underrepresented and stigmatized students' academic and career motivations are influenced by ST more broadly, particularly through influences on achievement orientations, sense of belonging, and intrinsic motivation. Such a focus moves conceptualizations of ST effects in education beyond the influence on a student's performance, skill level, and feelings of self-efficacy per se to experiencing greater belonging uncertainty and lower interest in stereotyped tasks and domains. These negative experiences are associated with important outcomes such as decreased persistence and domain identification, even among students who are high in achievement motivation. In this vein, we present and review support for the Motivational Experience Model of ST, a self-regulatory model framework for integrating research on ST, achievement goals, sense of belonging, and intrinsic motivation to make predictions for how stigmatized students' motivational experiences are maintained or disrupted, particularly over long periods of time. PMID:23894223

  17. Medical students' emotional development in early clinical experience: a model.

    PubMed

    Helmich, Esther; Bolhuis, Sanneke; Laan, Roland; Dornan, Tim; Koopmans, Raymond

    2014-08-01

    Dealing with emotions is a critical feature of professional behaviour. There are no comprehensive theoretical models, however, explaining how medical students learn about emotions. We aimed to explore factors affecting their emotions and how they learn to deal with emotions in themselves and others. During a first-year nursing attachment in hospitals and nursing homes, students wrote daily about their most impressive experiences, explicitly reporting what they felt, thought, and did. In a subsequent interview, they discussed those experiences in greater detail. Following a grounded theory approach, we conducted a constant comparative analysis, collecting and then interpreting data, and allowing the interpretation to inform subsequent data collection. Impressive experiences set up tensions, which gave rise to strong emotions. We identified four 'axes' along which tensions were experienced: 'idealism versus reality', 'critical distance versus adaptation', 'involvement versus detachment' and 'feeling versus displaying'. We found many factors, which influenced how respondents relieved those tensions. Their personal attributes and social relationships both inside and outside the medical community were important ones. Respondents' positions along the different dimensions, as determined by the balance between attributes and tensions, shaped their learning outcomes. Medical students' emotional development occurs through active participation in medical practice and having impressive experiences within relationships with patients and others on wards. Tensions along four dimensions give rise to strong emotions. Gaining insight into the many conditions that influence students' learning about emotions might support educators and supervisors in fostering medical students' emotional and professional development. PMID:23949724

  18. Modeling, simulation, and experiments of coating growth on nanofibers

    SciTech Connect

    Clemons, C. B.; Hamrick, P.; Heminger, J.; Kreider, K. L.; Young, G. W.; Buldum, A.; Evans, E.; Zhang, G.

    2008-02-15

    This work is a comparison of modeling and simulation results with experiments for an integrated experimental/modeling investigation of a procedure to coat nanofibers and core-clad nanostructures with thin film materials using plasma enhanced physical vapor deposition. In the experimental effort, electrospun polymer nanofibers are coated with metallic materials under different operating conditions to observe changes in the coating morphology. The modeling effort focuses on linking simple models at the reactor level, nanofiber level and atomic level to form a comprehensive model. The comprehensive model leads to the definition of an evolution equation for the coating free surface around an isolated nanofiber. This evolution equation was previously derived and solved under conditions of a nearly circular coating, with a concentration field that was only radially dependent and that was independent of the location of the coating free surface. These assumptions permitted the development of analytical expressions for the concentration field. The present work does not impose the above-mentioned conditions and considers numerical simulations of the concentration field that couple with level set simulations of the evolution equation for the coating free surface. Further, the cases of coating an isolated fiber as well as a multiple fiber mat are considered. Simulation results are compared with experimental results as the reactor pressure and power, as well as the nanofiber mat porosity, are varied.

  19. Dynamic crack initiation toughness : experiments and peridynamic modeling.

    SciTech Connect

    Foster, John T.

    2009-10-01

    This is a dissertation on research conducted studying the dynamic crack initiation toughness of a 4340 steel. Researchers have been conducting experimental testing of dynamic crack initiation toughness, K{sub Ic}, for many years, using many experimental techniques with vastly different trends in the results when reporting K{sub Ic} as a function of loading rate. The dissertation describes a novel experimental technique for measuring K{sub Ic} in metals using the Kolsky bar. The method borrows from improvements made in recent years in traditional Kolsky bar testing by using pulse shaping techniques to ensure a constant loading rate applied to the sample before crack initiation. Dynamic crack initiation measurements were reported on a 4340 steel at two different loading rates. The steel was shown to exhibit a rate dependence, with the recorded values of K{sub Ic} being much higher at the higher loading rate. Using the knowledge of this rate dependence as a motivation in attempting to model the fracture events, a viscoplastic constitutive model was implemented into a peridynamic computational mechanics code. Peridynamics is a newly developed theory in solid mechanics that replaces the classical partial differential equations of motion with integral-differential equations which do not require the existence of spatial derivatives in the displacement field. This allows for the straightforward modeling of unguided crack initiation and growth. To date, peridynamic implementations have used severely restricted constitutive models. This research represents the first implementation of a complex material model and its validation. After showing results comparing deformations to experimental Taylor anvil impact for the viscoplastic material model, a novel failure criterion is introduced to model the dynamic crack initiation toughness experiments. The failure model is based on an energy criterion and uses the K{sub Ic} values recorded experimentally as an input. The failure model

  20. Software reliability: Additional investigations into modeling with replicated experiments

    NASA Technical Reports Server (NTRS)

    Nagel, P. M.; Schotz, F. M.; Skirvan, J. A.

    1984-01-01

    The effects of programmer experience level, different program usage distributions, and programming languages are explored. All these factors affect performance, and some tentative relational hypotheses are presented. An analytic framework for replicated and non-replicated (traditional) software experiments is presented. A method of obtaining an upper bound on the error rate of the next error is proposed. The method was validated empirically by comparing forecasts with actual data. In all 14 cases the bound exceeded the observed parameter, albeit somewhat conservatively. Two other forecasting methods are proposed and compared to observed results. Although demonstrated relative to this framework that stages are neither independent nor exponentially distributed, empirical estimates show that the exponential assumption is nearly valid for all but the extreme tails of the distribution. Except for the dependence in the stage probabilities, Cox's model approximates to a degree what is being observed.

  1. Binary Time Series Modeling with Application to Adhesion Frequency Experiments

    PubMed Central

    Hung, Ying; Zarnitsyna, Veronika; Zhang, Yan; Zhu, Cheng; Wu, C. F. Jeff

    2011-01-01

    Repeated adhesion frequency assay is the only published method for measuring the kinetic rates of cell adhesion. Cell adhesion plays an important role in many physiological and pathological processes. Traditional analysis of adhesion frequency experiments assumes that the adhesion test cycles are independent Bernoulli trials. This assumption can often be violated in practice. Motivated by the analysis of repeated adhesion tests, a binary time series model incorporating random effects is developed in this paper. A goodness-of-fit statistic is introduced to assess the adequacy of distribution assumptions on the dependent binary data with random effects. The asymptotic distribution of the goodness-of-fit statistic is derived and its finite-sample performance is examined via a simulation study. Application of the proposed methodology to real data from a T-cell experiment reveals some interesting information, including the dependency between repeated adhesion tests. PMID:22180690

  2. Experience Modulates Vicarious Freezing in Rats: A Model for Empathy

    PubMed Central

    Atsak, Piray; Orre, Marie; Bakker, Petra; Cerliani, Leonardo; Roozendaal, Benno

    2011-01-01

    The study of the neural basis of emotional empathy has received a surge of interest in recent years but mostly employing human neuroimaging. A simpler animal model would pave the way for systematic single cell recordings and invasive manipulations of the brain regions implicated in empathy. Recent evidence has been put forward for the existence of empathy in rodents. In this study, we describe a potential model of empathy in female rats, in which we studied interactions between two rats: a witness observes a demonstrator experiencing a series of footshocks. By comparing the reaction of witnesses with or without previous footshock experience, we examine the role of prior experience as a modulator of empathy. We show that witnesses having previously experienced footshocks, but not naïve ones, display vicarious freezing behavior upon witnessing a cage-mate experiencing footshocks. Strikingly, the demonstrator's behavior was in turn modulated by the behavior of the witness: demonstrators froze more following footshocks if their witness froze more. Previous experiments have shown that rats emit ultrasonic vocalizations (USVs) when receiving footshocks. Thus, the role of USV in triggering vicarious freezing in our paradigm is examined. We found that experienced witness-demonstrator pairs emitted more USVs than naïve witness-demonstrator pairs, but the number of USVs was correlated with freezing in demonstrators, not in witnesses. Furthermore, playing back the USVs, recorded from witness-demonstrator pairs during the empathy test, did not induce vicarious freezing behavior in experienced witnesses. Thus, our findings confirm that vicarious freezing can be triggered in rats, and moreover it can be modulated by prior experience. Additionally, our result suggests that vicarious freezing is not triggered by USVs per se and it influences back onto the behavior of the demonstrator that had elicited the vicarious freezing in witnesses, introducing a paradigm to study empathy

  3. Selection Experiments in the Penna Model for Biological Aging

    NASA Astrophysics Data System (ADS)

    Medeiros, G.; Idiart, M. A.; de Almeida, R. M. C.

    We consider the Penna model for biological aging to investigate correlations between early fertility and late life survival rates in populations at equilibrium. We consider inherited initial reproduction ages together with a reproduction cost translated in a probability that mother and offspring die at birth, depending on the mother age. For convenient sets of parameters, the equilibrated populations present genetic variability in what regards both genetically programmed death age and initial reproduction age. In the asexual Penna model, a negative correlation between early life fertility and late life survival rates naturally emerges in the stationary solutions. In the sexual Penna model, selection experiments are performed where individuals are sorted by initial reproduction age from the equilibrated populations and the separated populations are evolved independently. After a transient, a negative correlation between early fertility and late age survival rates also emerges in the sense that populations that start reproducing earlier present smaller average genetically programmed death age. These effects appear due to the age structure of populations in the steady state solution of the evolution equations. We claim that the same demographic effects may be playing an important role in selection experiments in the laboratory.

  4. Rolling friction—models and experiment. An undergraduate student project

    NASA Astrophysics Data System (ADS)

    Vozdecký, L.; Bartoš, J.; Musilová, J.

    2014-09-01

    In this paper the rolling friction (rolling resistance) model is studied theoretically and experimentally in undergraduate level fundamental general physics courses. Rolling motions of a cylinder along horizontal or inclined planes are studied by simple experiments, measuring deformations of the underlay or of the rolling body. The rolling of a hard cylinder on a soft underlay as well as of a soft cylinder on a hard underlay is studied. The experimental data are treated by the open source software Tracker, appropriate for use at the undergraduate level of physics. Interpretation of results is based on elementary considerations comprehensible to university students—beginners. It appears that the commonly accepted model of rolling resistance based on the idea of a warp (little bulge) on the underlay in front of the rolling body does not correspond with experimental results even for the soft underlay and hard rolling body. The alternative model of the rolling resistance is suggested in agreement with experiment and the corresponding concept of the rolling resistance coefficient is presented. In addition to the obtained results we can conclude that the project can be used as a task for students in practical exercises of fundamental general physics undergraduate courses. Projects of similar type effectively contribute to the development of the physical thinking of students.

  5. Solute and heat transport model of the Henry and Hilleke laboratory experiment

    USGS Publications Warehouse

    Langevin, C.D.; Dausman, A.M.; Sukop, M.C.

    2010-01-01

    SEAWAT is a coupled version of MODFLOW and MT3DMS designed to simulate variable-density ground water flow and solute transport. The most recent version of SEAWAT, called SEAWAT Version 4, includes new capabilities to represent simultaneous multispecies solute and heat transport. To test the new features in SEAWAT, the laboratory experiment of Henry and Hilleke (1972) was simulated. Henry and Hilleke used warm fresh water to recharge a large sand-filled glass tank. A cold salt water boundary was represented on one side. Adjustable heating pads were used to heat the bottom and left sides of the tank. In the laboratory experiment, Henry and Hilleke observed both salt water and fresh water flow systems separated by a narrow transition zone. After minor tuning of several input parameters with a parameter estimation program, results from the SEAWAT simulation show good agreement with the experiment. SEAWAT results suggest that heat loss to the room was more than expected by Henry and Hilleke, and that multiple thermal convection cells are the likely cause of the widened transition zone near the hot end of the tank. Other computer programs with similar capabilities may benefit from benchmark testing with the Henry and Hilleke laboratory experiment. Journal Compilation ?? 2009 National Ground Water Association.

  6. Solute and heat transport model of the Henry and hilleke laboratory experiment.

    PubMed

    Langevin, Christian D; Dausman, Alyssa M; Sukop, Michael C

    2010-01-01

    SEAWAT is a coupled version of MODFLOW and MT3DMS designed to simulate variable-density ground water flow and solute transport. The most recent version of SEAWAT, called SEAWAT Version 4, includes new capabilities to represent simultaneous multispecies solute and heat transport. To test the new features in SEAWAT, the laboratory experiment of Henry and Hilleke (1972) was simulated. Henry and Hilleke used warm fresh water to recharge a large sand-filled glass tank. A cold salt water boundary was represented on one side. Adjustable heating pads were used to heat the bottom and left sides of the tank. In the laboratory experiment, Henry and Hilleke observed both salt water and fresh water flow systems separated by a narrow transition zone. After minor tuning of several input parameters with a parameter estimation program, results from the SEAWAT simulation show good agreement with the experiment. SEAWAT results suggest that heat loss to the room was more than expected by Henry and Hilleke, and that multiple thermal convection cells are the likely cause of the widened transition zone near the hot end of the tank. Other computer programs with similar capabilities may benefit from benchmark testing with the Henry and Hilleke laboratory experiment. PMID:19563419

  7. Integrated healthy workplace model: An experience from North Indian industry

    PubMed Central

    Thakur, Jarnail Singh; Bains, Puneet; Kar, Sitanshu Sekhar; Wadhwa, Sanjay; Moirangthem, Prabha; Kumar, Rajesh; Wadwalker, Sanjay; Sharma, Yashpal

    2012-01-01

    Background: Keeping in view of rapid industrialization and growing Indian economy, there has been a substantial increase in the workforce in India. Currently there is no organized workplace model for promoting health of industrial workers in India. Objective: To develop and implement a healthy workplace model in three industrial settings of North India. Materials and Methods: An operations research was conducted for 12 months in purposively selected three industries of Chandigarh. In phase I, a multi-stakeholder workshop was conducted to finalize the components and tools for the healthy workplace model. NCD risk factors were assessed in 947 employees in these three industries. In phase II, the healthy workplace model was implemented on pilot basis for a period of 12 months in these three industries to finalize the model. Findings: Healthy workplace committee with involvement of representatives of management, labor union and research organization was formed in three industries. Various tools like comprehensive and rapid healthy workplace assessment forms, NCD work-lite format for risk factors surveillance and monitoring and evaluation format were developed. The prevalence of tobacco use, ever alcoholics was found to be 17.8% and 47%, respectively. Around one-third (28%) of employees complained of back pain in the past 12 months. Healthy workplace model with focus on three key components (physical environment, psychosocial work environment, and promoting healthy habits) was developed, implemented on pilot basis, and finalized based on experience in participating industries. A stepwise approach for model with a core, expanded, and optional components were also suggested. An accreditation system is also required for promoting healthy workplace program. Conclusion: Integrated healthy workplace model is feasible, could be implemented in industrial setting in northern India and needs to be pilot tested in other parts of the country. PMID:23776318

  8. Discrete Harmonic Model for Stacked Membranes: Theory and Experiment

    NASA Astrophysics Data System (ADS)

    Lei, Ning; Safinya, C. R.; Bruinsma, R. F.

    1995-08-01

    The discrete harmonic (DH) model has been developed which describes the static structure factor of stacked membranes. The (DH) model was used to analyze a synchrotron small-angle X-ray scattering study in stacked membranes. We studied lyotropic lamellar Lα phase samples in a quaternary mixture consisting of thin water layers coated with surfactant sodium dodecyl sulfate (SDS) and cosurfactant (pentanol) molecules, separated by oil. The experiments on highly oriented Lα phase samples covered a large interlayer spacing range from d=49.1 to 255.8 Å produced by dodecane dilution, which considerably exceeded those of previous high resolution synchrotron scattering studies of powder samples. Two significant differences emerge between the (DH) model and the continuum Caillé model description of smectic-A liquid crystals and multilayer membranes. First, whereas the continuum model is necessarily restricted to the vicinity of the Bragg peaks of the structure factor, the discrete nature of the (DH) model allowed us to fit the experimentally measured X-ray structure factor over the full range of wave-vectors and dilutions. This enabled measurements of the membrane bending and multilayer compressiblity elastic constants kappa and B separately, in contrast to the continuum model which gives reliable measurement of the product kappa B. Second, the (DH) model is able to account for the universally observed anomalously large small angle scattering (SAS) in strongly fluctuating dilute fluid multilayer membranes. The (SAS) is shown to contain contributions both due to concentration fluctuations described previously by Porte et al. and Nallet et al. and unexpectedly from a divergent thermal-coherent diffraction effect which dominates in single crystal multilayers.

  9. Inverse modelling of multiple infiltration-outflow experiments

    NASA Astrophysics Data System (ADS)

    Sobotková, M.; Snehota, M.; Dohnal, M.; Cislerova, M.

    2009-04-01

    Changes of (quasi)steady state water flow rates were observed in laboratory infiltration experiments done on columns of compacted sand and on two undisturbed soil columns of sandy loam and loamy sand cambisol soil. Infiltration-outflow experiments consisted of series of ponded infiltration runs with seepage face boundary condition at the lower end of columns. The initial water contents were different for each run. The results of the experiment done on an undisturbed soil column showed that the flux rates and water contents measured during quasi-steady state differ between infiltration runs. This finding contradicts the standard theory. The fluctuations of the water content during the steady state flow can be ascribed to the variations in volume of the entrapped air. The same behaviour was not observed in the sample of homogeneous sand. Computer tomography was used to characterize the structure of the undisturbed soil sample with focus on potential preferential flow pathways. In order to asses the changes between runs quantitatively, hydraulic characteristics were estimated for each infiltration run separately by inverse modelling. Experimental outflow data and tensiometric pressure head data were used as an input for inverse modelling. Numerical code based on dual permeability approach was coupled with parameter estimator. Result of the inverse modelling for each column is specific set of hydraulic properties for each infiltration run of particular soil column. Since we hypothesise that the steady state flow is affected by soil water content at the beginning of the infiltration run, we will study the relationships between initial moistures and hydraulic parameters values. Furthermore we will test if the above phenomena can be ascribed to hysteresis of hydraulic functions.

  10. Coupled Thermal-Chemical-Mechanical Modeling of Validation Cookoff Experiments

    SciTech Connect

    ERIKSON,WILLIAM W.; SCHMITT,ROBERT G.; ATWOOD,A.I.; CURRAN,P.D.

    2000-11-27

    The cookoff of energetic materials involves the combined effects of several physical and chemical processes. These processes include heat transfer, chemical decomposition, and mechanical response. The interaction and coupling between these processes influence both the time-to-event and the violence of reaction. The prediction of the behavior of explosives during cookoff, particularly with respect to reaction violence, is a challenging task. To this end, a joint DoD/DOE program has been initiated to develop models for cookoff, and to perform experiments to validate those models. In this paper, a series of cookoff analyses are presented and compared with data from a number of experiments for the aluminized, RDX-based, Navy explosive PBXN-109. The traditional thermal-chemical analysis is used to calculate time-to-event and characterize the heat transfer and boundary conditions. A reaction mechanism based on Tarver and McGuire's work on RDX{sup 2} was adjusted to match the spherical one-dimensional time-to-explosion data. The predicted time-to-event using this reaction mechanism compares favorably with the validation tests. Coupled thermal-chemical-mechanical analysis is used to calculate the mechanical response of the confinement and the energetic material state prior to ignition. The predicted state of the material includes the temperature, stress-field, porosity, and extent of reaction. There is little experimental data for comparison to these calculations. The hoop strain in the confining steel tube gives an estimation of the radial stress in the explosive. The inferred pressure from the measured hoop strain and calculated radial stress agree qualitatively. However, validation of the mechanical response model and the chemical reaction mechanism requires more data. A post-ignition burn dynamics model was applied to calculate the confinement dynamics. The burn dynamics calculations suffer from a lack of characterization of the confinement for the flaw

  11. Systematic Study of the Content of Phytochemicals in Fresh and Fresh-Cut Vegetables

    PubMed Central

    Alarcón-Flores, María Isabel; Romero-González, Roberto; Martínez Vidal, José Luis; Garrido Frenich, Antonia

    2015-01-01

    Vegetables and fruits have beneficial properties for human health, because of the presence of phytochemicals, but their concentration can fluctuate throughout the year. A systematic study of the phytochemical content in tomato, eggplant, carrot, broccoli and grape (fresh and fresh-cut) has been performed at different seasons, using liquid chromatography coupled to triple quadrupole mass spectrometry. It was observed that phenolic acids (the predominant group in carrot, eggplant and tomato) were found at higher concentrations in fresh carrot than in fresh-cut carrot. However, in the case of eggplant, they were detected at a higher content in fresh-cut than in fresh samples. Regarding tomato, the differences in the content of phenolic acids between fresh and fresh-cut were lower than in other matrices, except in winter sampling, where this family was detected at the highest concentration in fresh tomato. In grape, the flavonols content (predominant group) was higher in fresh grape than in fresh-cut during all samplings. The content of glucosinolates was lower in fresh-cut broccoli than in fresh samples in winter and spring sampling, although this trend changes in summer and autumn. In summary, phytochemical concentration did show significant differences during one-year monitoring, and the families of phytochemicals presented different behaviors depending on the matrix studied. PMID:26783709

  12. Systematic Study of the Content of Phytochemicals in Fresh and Fresh-Cut Vegetables.

    PubMed

    Alarcón-Flores, María Isabel; Romero-González, Roberto; Vidal, José Luis Martínez; Frenich, Antonia Garrido

    2015-01-01

    Vegetables and fruits have beneficial properties for human health, because of the presence of phytochemicals, but their concentration can fluctuate throughout the year. A systematic study of the phytochemical content in tomato, eggplant, carrot, broccoli and grape (fresh and fresh-cut) has been performed at different seasons, using liquid chromatography coupled to triple quadrupole mass spectrometry. It was observed that phenolic acids (the predominant group in carrot, eggplant and tomato) were found at higher concentrations in fresh carrot than in fresh-cut carrot. However, in the case of eggplant, they were detected at a higher content in fresh-cut than in fresh samples. Regarding tomato, the differences in the content of phenolic acids between fresh and fresh-cut were lower than in other matrices, except in winter sampling, where this family was detected at the highest concentration in fresh tomato. In grape, the flavonols content (predominant group) was higher in fresh grape than in fresh-cut during all samplings. The content of glucosinolates was lower in fresh-cut broccoli than in fresh samples in winter and spring sampling, although this trend changes in summer and autumn. In summary, phytochemical concentration did show significant differences during one-year monitoring, and the families of phytochemicals presented different behaviors depending on the matrix studied. PMID:26783709

  13. Discrete Element Modeling (DEM) of Triboelectrically Charged Particles: Revised Experiments

    NASA Technical Reports Server (NTRS)

    Hogue, Michael D.; Calle, Carlos I.; Curry, D. R.; Weitzman, P. S.

    2008-01-01

    In a previous work, the addition of basic screened Coulombic electrostatic forces to an existing commercial discrete element modeling (DEM) software was reported. Triboelectric experiments were performed to charge glass spheres rolling on inclined planes of various materials. Charge generation constants and the Q/m ratios for the test materials were calculated from the experimental data and compared to the simulation output of the DEM software. In this paper, we will discuss new values of the charge generation constants calculated from improved experimental procedures and data. Also, planned work to include dielectrophoretic, Van der Waals forces, and advanced mechanical forces into the software will be discussed.

  14. Experiments of reconstructing discrete atmospheric dynamic models from data (I)

    NASA Astrophysics Data System (ADS)

    Lin, Zhenshan; Zhu, Yanyu; Deng, Ziwang

    1995-03-01

    In this paper, we give some experimental results of our study in reconstructing discrete atmospheric dynamic models from data. After a great deal of numerical experiments, we found that the logistic map, x n + 1 = 1- μx {2/n}, could be used in monthly mean temperature prediction when it was approaching the chaotic region, and its predictive results were in reverse states to the practical data. This means that the nonlinear developing behavior of the monthly mean temperature system is bifurcating back into the critical chaotic states from the chaotic ones.

  15. The NASA/GISS Mars general circulation model: Preliminary experiments

    NASA Technical Reports Server (NTRS)

    Allison, Michael; Chandler, M. A.; Delgenio, A. D.; Lacis, A.; Rind, D.; Rossow, W. B.; Travis, L. D.; Zhou, W.

    1993-01-01

    The NASA/GISS Mars General Circulation Model (GCM) is an adapted version of the GISS Global Climate/Middle Atmosphere Model, specifically developed for the diagnostic validation and objective analysis of measured atmospheric temperatures from the Mars Observer Pressure Modulator Infrared Radiometer (PMIRR) experiment. The GISS Mars GCM has 23 vertical layers extending from the surface to approximately 80 km altitude, representing a vertical resolution of about 0.3 scale heights. The primitive (vertically hydrostatic) equations are solved in finite difference form on the Krakawa B grid, with a horizontal resolution of 8 deg x 10 deg (latitude-longitude). The model includes a diurnal solar cycle, heat transport within a two-layer ground, and a high-order 'slopes-scheme' for the advection of heat in the upper atmosphere. The radiative transfer scheme is based on the correlated k distribution method for the treatment of nongray gaseous absorption thermal emission, and multiple scattering, including options for suspended dust. A special feature of the model of particular importance for Mars is a parameterization of gravity-wave-induced drag incorporating orographic forcing, wind shear, convection, and radiative damping. The implementation of the GISS Mars model includes global maps of topography, roughness, and albedo.

  16. Blast Loading Experiments of Surrogate Models for Tbi Scenarios

    NASA Astrophysics Data System (ADS)

    Alley, M. D.; Son, S. F.

    2009-12-01

    This study aims to characterize the interaction of explosive blast waves through simulated anatomical models. We have developed physical models and a systematic approach for testing traumatic brain injury (TBI) mechanisms and occurrences. A simplified series of models consisting of spherical PMMA shells housing synthetic gelatins as brain simulants have been utilized. A series of experiments was conducted to compare the sensitivity of the system response to mechanical properties of the simulants under high strain-rate explosive blasts. Small explosive charges were directed at the models to produce a realistic blast wave in a scaled laboratory test cell setting. Blast profiles were measured and analyzed to compare system response severity. High-speed shadowgraph imaging captured blast wave interaction with the head model while particle tracking captured internal response for displacement and strain correlation. The results suggest amplification of shock waves inside the head near material interfaces due to impedance mismatches. In addition, significant relative displacement was observed between the interacting materials suggesting large strain values of nearly 5%. Further quantitative results were obtained through shadowgraph imaging of the blasts confirming a separation of time scales between blast interaction and bulk movement. These results lead to the conclusion that primary blast effects could cause TBI occurrences.

  17. Nursing preceptors' experiences of two clinical education models.

    PubMed

    Mamhidir, Anna-Greta; Kristofferzon, Marja-Leena; Hellström-Hyson, Eva; Persson, Elisabeth; Mårtensson, Gunilla

    2014-08-01

    Preceptors play an important role in the process of developing students' knowledge and skills. There is an ongoing search for the best learning and teaching models in clinical education. Little is known about preceptors' perspectives on different models. The aim of the study was to describe nursing preceptors' experiences of two clinical models of clinical education: peer learning and traditional supervision. A descriptive design and qualitative approach was used. Eighteen preceptors from surgical and medical departments at two hospitals were interviewed, ten representing peer learning (student work in pairs) and eight traditional supervision (one student follows a nurse during a shift). The findings showed that preceptors using peer learning created room for students to assume responsibility for their own learning, challenged students' knowledge by refraining from stepping in and encouraged critical thinking. Using traditional supervision, the preceptors' individual ambitions influenced the preceptorship and their own knowledge was empathized as being important to impart. They demonstrated, observed and gradually relinquished responsibility to the students. The choice of clinical education model is important. Peer learning seemed to create learning environments that integrate clinical and academic skills. Investigation of pedagogical models in clinical education should be of major concern to managers and preceptors. PMID:24512652

  18. Dissolution-precipitation processes in tank experiments for testing numerical models for reactive transport calculations: Experiments and modelling

    NASA Astrophysics Data System (ADS)

    Poonoosamy, Jenna; Kosakowski, Georg; Van Loon, Luc R.; Mäder, Urs

    2015-06-01

    In the context of testing reactive transport codes and their underlying conceptual models, a simple 2D reactive transport experiment was developed. The aim was to use simple chemistry and design a reproducible and fast to conduct experiment, which is flexible enough to include several process couplings: advective-diffusive transport of solutes, effect of liquid phase density on advective transport, and kinetically controlled dissolution/precipitation reactions causing porosity changes. A small tank was filled with a reactive layer of strontium sulfate (SrSO4) of two different grain sizes, sandwiched between two layers of essentially non-reacting quartz sand (SiO2). A highly concentrated solution of barium chloride was injected to create an asymmetric flow field. Once the barium chloride reached the reactive layer, it forced the transformation of strontium sulfate into barium sulfate (BaSO4). Due to the higher molar volume of barium sulfate, its precipitation caused a decrease of porosity and lowered the permeability. Changes in the flow field were observed with help of dye tracer tests. The experiments were modelled using the reactive transport code OpenGeosys-GEM. Tests with non-reactive tracers performed prior to barium chloride injection, as well as the density-driven flow (due to the high concentration of barium chloride solution), could be well reproduced by the numerical model. To reproduce the mineral bulk transformation with time, two populations of strontium sulfate grains with different kinetic rates of dissolution were applied. However, a default porosity permeability relationship was unable to account for measured pressure changes. Post mortem analysis of the strontium sulfate reactive medium provided useful information on the chemical and structural changes occurring at the pore scale at the interface that were considered in our model to reproduce the pressure evolution with time.

  19. Dissolution-precipitation processes in tank experiments for testing numerical models for reactive transport calculations: Experiments and modelling.

    PubMed

    Poonoosamy, Jenna; Kosakowski, Georg; Van Loon, Luc R; Mäder, Urs

    2015-01-01

    In the context of testing reactive transport codes and their underlying conceptual models, a simple 2D reactive transport experiment was developed. The aim was to use simple chemistry and design a reproducible and fast to conduct experiment, which is flexible enough to include several process couplings: advective-diffusive transport of solutes, effect of liquid phase density on advective transport, and kinetically controlled dissolution/precipitation reactions causing porosity changes. A small tank was filled with a reactive layer of strontium sulfate (SrSO4) of two different grain sizes, sandwiched between two layers of essentially non-reacting quartz sand (SiO2). A highly concentrated solution of barium chloride was injected to create an asymmetric flow field. Once the barium chloride reached the reactive layer, it forced the transformation of strontium sulfate into barium sulfate (BaSO4). Due to the higher molar volume of barium sulfate, its precipitation caused a decrease of porosity and lowered the permeability. Changes in the flow field were observed with help of dye tracer tests. The experiments were modelled using the reactive transport code OpenGeosys-GEM. Tests with non-reactive tracers performed prior to barium chloride injection, as well as the density-driven flow (due to the high concentration of barium chloride solution), could be well reproduced by the numerical model. To reproduce the mineral bulk transformation with time, two populations of strontium sulfate grains with different kinetic rates of dissolution were applied. However, a default porosity permeability relationship was unable to account for measured pressure changes. Post mortem analysis of the strontium sulfate reactive medium provided useful information on the chemical and structural changes occurring at the pore scale at the interface that were considered in our model to reproduce the pressure evolution with time. PMID:25805363

  20. Modelling hot electron generation in short pulse target heating experiments

    NASA Astrophysics Data System (ADS)

    Sircombe, N. J.; Hughes, S. J.

    2013-11-01

    Target heating experiments planned for the Orion laser facility, and electron beam driven fast ignition schemes, rely on the interaction of a short pulse high intensity laser with dense material to generate a flux of energetic electrons. It is essential that the characteristics of this electron source are well known in order to inform transport models in radiation hydrodynamics codes and allow effective evaluation of experimental results and forward modelling of future campaigns. We present results obtained with the particle in cell (PIC) code EPOCH for realistic target and laser parameters, including first and second harmonic light. The hot electron distributions are characterised and their implications for onward transport and target heating are considered with the aid of the Monte-Carlo transport code THOR.

  1. First experience of vectorizing electromagnetic physics models for detector simulation

    SciTech Connect

    Amadio, G.; Apostolakis, J.; Bandieramonte, M.; Bianchini, C.; Bitzes, G.; Brun, R.; Canal, P.; Carminati, F.; Licht, J.de Fine; Duhem, L.; Elvira, D.; Gheata, A.; Jun, S. Y.; Lima, G.; Novak, M.; Presbyterian, M.; Shadura, O.; Seghal, R.; Wenzel, S.

    2015-12-23

    The recent emergence of hardware architectures characterized by many-core or accelerated processors has opened new opportunities for concurrent programming models taking advantage of both SIMD and SIMT architectures. The GeantV vector prototype for detector simulations has been designed to exploit both the vector capability of mainstream CPUs and multi-threading capabilities of coprocessors including NVidia GPUs and Intel Xeon Phi. The characteristics of these architectures are very different in terms of the vectorization depth, parallelization needed to achieve optimal performance or memory access latency and speed. An additional challenge is to avoid the code duplication often inherent to supporting heterogeneous platforms. In this paper we present the first experience of vectorizing electromagnetic physics models developed for the GeantV project.

  2. First experience of vectorizing electromagnetic physics models for detector simulation

    NASA Astrophysics Data System (ADS)

    Amadio, G.; Apostolakis, J.; Bandieramonte, M.; Bianchini, C.; Bitzes, G.; Brun, R.; Canal, P.; Carminati, F.; de Fine Licht, J.; Duhem, L.; Elvira, D.; Gheata, A.; Jun, S. Y.; Lima, G.; Novak, M.; Presbyterian, M.; Shadura, O.; Seghal, R.; Wenzel, S.

    2015-12-01

    The recent emergence of hardware architectures characterized by many-core or accelerated processors has opened new opportunities for concurrent programming models taking advantage of both SIMD and SIMT architectures. The GeantV vector prototype for detector simulations has been designed to exploit both the vector capability of mainstream CPUs and multi-threading capabilities of coprocessors including NVidia GPUs and Intel Xeon Phi. The characteristics of these architectures are very different in terms of the vectorization depth, parallelization needed to achieve optimal performance or memory access latency and speed. An additional challenge is to avoid the code duplication often inherent to supporting heterogeneous platforms. In this paper we present the first experience of vectorizing electromagnetic physics models developed for the GeantV project.

  3. Thermosphere-ionosphere coupling - An experiment in interactive modeling

    NASA Technical Reports Server (NTRS)

    Forbes, Jeffrey M.; Roble, Raymond G.

    1990-01-01

    Using the NCAR thermosphere general circulation model, a series of controlled experiments is performed to investigate the interactive coupling between ionospheric plasma densities and thermospheric neutral winds. The interaction is accomplished by parameterizing the F layer peak height, h(m)F2, in an empirical ionospheric model in terms of the meridional wind, v(south), and by forcing the h(m)F2 and the v(south) parameters to remain mutually coupled in a dynamical calculation. It was found that mutual coupling between forcing and meridional wind is weak during the daytime when the F layer exhibits a broad vertical structure. At night, when the F2 layer is more localized, the neutral dynamical structure is dependent on whether forcing is significantly above or below the altitude (about 275-300 km) at which ion drag effectively competes with viscosity in the neutral momentum balance.

  4. Tailoring the fresh state properties of concrete

    NASA Astrophysics Data System (ADS)

    Tregger, Nathan Allen

    In this research, two types of concrete whose performance relies on their fresh-state abilities will be discussed. The first is self-consolidating concrete, which possesses high flowability without aggregate segregation. Quality control of flowability is typically predicted by the final diameter ( Df) of the slump-flow test, which in turn, has been related to yield stress of the fresh concrete. Currently, there are no reliable measures of viscosity from a field-friendly test such as the slump-flow test. It will be demonstrated that the viscosity can be related to the time to final diameter (Tf) from the minislump-flow tests for cement pastes. This relationship is extended to concrete systems where T f of the slump-flow test is correlated to dynamic segregation. For the concrete system, Tf was increased systematically using a viscosity modifying agent, while the Df was kept constant by adjusting the superplasticizer content. Segregation is determined by measuring the radial aggregate distribution from the slump-flow test. The results demonstrate that increasing the Tf improves dynamic segregation resistance. Furthermore, Tf was more indicative of viscosity than the time to reach a diameter of 50 cm (T50), which is currently used in the field as a measure of viscosity. Computational models are implemented to investigate these relationships for both cement and concrete systems. The second type of concrete is an improved slipform concrete with the ability to consolidate under minimal external energy yet maintain shape stability after being slipformed. This balance between flowability and shape stability is achieved through combination of fly ash and small dosages of micro and nano clays. A microstructural investigation of the effect of clays on the fresh state is carried out to relate macro behaviors with changes in the paste microstructure. Shear and compressive rheology techniques are used to measure how the solids volume fraction of the suspensions with different

  5. Social Aggregation in Pea Aphids: Experiment and Random Walk Modeling

    PubMed Central

    Nilsen, Christa; Paige, John; Warner, Olivia; Mayhew, Benjamin; Sutley, Ryan; Lam, Matthew; Bernoff, Andrew J.; Topaz, Chad M.

    2013-01-01

    From bird flocks to fish schools and ungulate herds to insect swarms, social biological aggregations are found across the natural world. An ongoing challenge in the mathematical modeling of aggregations is to strengthen the connection between models and biological data by quantifying the rules that individuals follow. We model aggregation of the pea aphid, Acyrthosiphon pisum. Specifically, we conduct experiments to track the motion of aphids walking in a featureless circular arena in order to deduce individual-level rules. We observe that each aphid transitions stochastically between a moving and a stationary state. Moving aphids follow a correlated random walk. The probabilities of motion state transitions, as well as the random walk parameters, depend strongly on distance to an aphid's nearest neighbor. For large nearest neighbor distances, when an aphid is essentially isolated, its motion is ballistic with aphids moving faster, turning less, and being less likely to stop. In contrast, for short nearest neighbor distances, aphids move more slowly, turn more, and are more likely to become stationary; this behavior constitutes an aggregation mechanism. From the experimental data, we estimate the state transition probabilities and correlated random walk parameters as a function of nearest neighbor distance. With the individual-level model established, we assess whether it reproduces the macroscopic patterns of movement at the group level. To do so, we consider three distributions, namely distance to nearest neighbor, angle to nearest neighbor, and percentage of population moving at any given time. For each of these three distributions, we compare our experimental data to the output of numerical simulations of our nearest neighbor model, and of a control model in which aphids do not interact socially. Our stochastic, social nearest neighbor model reproduces salient features of the experimental data that are not captured by the control. PMID:24376691

  6. Social aggregation in pea aphids: experiment and random walk modeling.

    PubMed

    Nilsen, Christa; Paige, John; Warner, Olivia; Mayhew, Benjamin; Sutley, Ryan; Lam, Matthew; Bernoff, Andrew J; Topaz, Chad M

    2013-01-01

    From bird flocks to fish schools and ungulate herds to insect swarms, social biological aggregations are found across the natural world. An ongoing challenge in the mathematical modeling of aggregations is to strengthen the connection between models and biological data by quantifying the rules that individuals follow. We model aggregation of the pea aphid, Acyrthosiphon pisum. Specifically, we conduct experiments to track the motion of aphids walking in a featureless circular arena in order to deduce individual-level rules. We observe that each aphid transitions stochastically between a moving and a stationary state. Moving aphids follow a correlated random walk. The probabilities of motion state transitions, as well as the random walk parameters, depend strongly on distance to an aphid's nearest neighbor. For large nearest neighbor distances, when an aphid is essentially isolated, its motion is ballistic with aphids moving faster, turning less, and being less likely to stop. In contrast, for short nearest neighbor distances, aphids move more slowly, turn more, and are more likely to become stationary; this behavior constitutes an aggregation mechanism. From the experimental data, we estimate the state transition probabilities and correlated random walk parameters as a function of nearest neighbor distance. With the individual-level model established, we assess whether it reproduces the macroscopic patterns of movement at the group level. To do so, we consider three distributions, namely distance to nearest neighbor, angle to nearest neighbor, and percentage of population moving at any given time. For each of these three distributions, we compare our experimental data to the output of numerical simulations of our nearest neighbor model, and of a control model in which aphids do not interact socially. Our stochastic, social nearest neighbor model reproduces salient features of the experimental data that are not captured by the control. PMID:24376691

  7. A new Geoengineering Model Intercomparison Project (GeoMIP) experiment designed for climate and chemistry models

    NASA Astrophysics Data System (ADS)

    Tilmes, S.; Mills, M. J.; Niemeier, U.; Schmidt, H.; Robock, A.; Kravitz, B.; Lamarque, J.-F.; Pitari, G.; English, J. M.

    2015-01-01

    A new Geoengineering Model Intercomparison Project (GeoMIP) experiment "G4 specified stratospheric aerosols" (short name: G4SSA) is proposed to investigate the impact of stratospheric aerosol geoengineering on atmosphere, chemistry, dynamics, climate, and the environment. In contrast to the earlier G4 GeoMIP experiment, which requires an emission of sulfur dioxide (SO2) into the model, a prescribed aerosol forcing file is provided to the community, to be consistently applied to future model experiments between 2020 and 2100. This stratospheric aerosol distribution, with a total burden of about 2 Tg S has been derived using the ECHAM5-HAM microphysical model, based on a continuous annual tropical emission of 8 Tg SO2 yr-1. A ramp-up of geoengineering in 2020 and a ramp-down in 2070 over a period of 2 years are included in the distribution, while a background aerosol burden should be used for the last 3 decades of the experiment. The performance of this experiment using climate and chemistry models in a multi-model comparison framework will allow us to better understand the impact of geoengineering and its abrupt termination after 50 years in a changing environment. The zonal and monthly mean stratospheric aerosol input data set is available at https://www2.acd.ucar.edu/gcm/geomip-g4-specified-stratospheric-aerosol-data-set.

  8. A new Geoengineering Model Intercomparison Project (GeoMIP) experiment designed for climate and chemistry models

    DOE PAGESBeta

    Tilmes, S.; Mills, Mike; Niemeier, Ulrike; Schmidt, Hauke; Robock, Alan; Kravitz, Benjamin S.; Lamarque, J. F.; Pitari, G.; English, J. M.

    2015-01-15

    A new Geoengineering Model Intercomparison Project (GeoMIP) experiment "G4 specified stratospheric aerosols" (short name: G4SSA) is proposed to investigate the impact of stratospheric aerosol geoengineering on atmosphere, chemistry, dynamics, climate, and the environment. In contrast to the earlier G4 GeoMIP experiment, which requires an emission of sulfur dioxide (SO₂) into the model, a prescribed aerosol forcing file is provided to the community, to be consistently applied to future model experiments between 2020 and 2100. This stratospheric aerosol distribution, with a total burden of about 2 Tg S has been derived using the ECHAM5-HAM microphysical model, based on a continuous annualmore » tropical emission of 8 Tg SO₂ yr⁻¹. A ramp-up of geoengineering in 2020 and a ramp-down in 2070 over a period of 2 years are included in the distribution, while a background aerosol burden should be used for the last 3 decades of the experiment. The performance of this experiment using climate and chemistry models in a multi-model comparison framework will allow us to better understand the impact of geoengineering and its abrupt termination after 50 years in a changing environment. The zonal and monthly mean stratospheric aerosol input data set is available at https://www2.acd.ucar.edu/gcm/geomip-g4-specified-stratospheric-aerosol-data-set.« less

  9. A new Geoengineering Model Intercomparison Project (GeoMIP) experiment designed for climate and chemistry models

    SciTech Connect

    Tilmes, S.; Mills, Mike; Niemeier, Ulrike; Schmidt, Hauke; Robock, Alan; Kravitz, Benjamin S.; Lamarque, J. F.; Pitari, G.; English, J. M.

    2015-01-15

    A new Geoengineering Model Intercomparison Project (GeoMIP) experiment "G4 specified stratospheric aerosols" (short name: G4SSA) is proposed to investigate the impact of stratospheric aerosol geoengineering on atmosphere, chemistry, dynamics, climate, and the environment. In contrast to the earlier G4 GeoMIP experiment, which requires an emission of sulfur dioxide (SO₂) into the model, a prescribed aerosol forcing file is provided to the community, to be consistently applied to future model experiments between 2020 and 2100. This stratospheric aerosol distribution, with a total burden of about 2 Tg S has been derived using the ECHAM5-HAM microphysical model, based on a continuous annual tropical emission of 8 Tg SO₂ yr⁻¹. A ramp-up of geoengineering in 2020 and a ramp-down in 2070 over a period of 2 years are included in the distribution, while a background aerosol burden should be used for the last 3 decades of the experiment. The performance of this experiment using climate and chemistry models in a multi-model comparison framework will allow us to better understand the impact of geoengineering and its abrupt termination after 50 years in a changing environment. The zonal and monthly mean stratospheric aerosol input data set is available at https://www2.acd.ucar.edu/gcm/geomip-g4-specified-stratospheric-aerosol-data-set.

  10. Development of the Play Experience Model to Enhance Desirable Qualifications of Early Childhood

    ERIC Educational Resources Information Center

    Panpum, Watchara; Soonthornrojana, Wimonrat; Nakunsong, Thatsanee

    2015-01-01

    The objectives of this research were to develop the play experience model and to study the effect of usage in play experience model for enhancing the early childhood's desirable qualification. There were 3 phases of research: 1) the document and context in experience management were studied, 2) the play experience model was developed, and 3) the…

  11. Estimating fresh biomass of maize plants from their RGB images in greenhouse phenotyping

    NASA Astrophysics Data System (ADS)

    Ge, Yufeng; Pandey, Piyush; Bai, Geng

    2016-05-01

    High throughput phenotyping (HTP) is an emerging frontier field across many basic and applied plant science disciplines. RGB imaging is most widely used in HTP to extract image-based phenotypes such as pixel volume or projected area. These image-based phenotypes are further used to derive plant physical parameters including plant fresh biomass, plant dry biomass, water use efficiency etc. In this paper, we investigated the robustness of regression models to predict fresh biomass of maize plants from image-based phenotypes. Data used in this study were from three different experiments. Data were grouped into five datasets, two for model development and three for independent model validation. Three image-derived phenotypes were investigated: BioVolume, Projected.Area.1, and Projected.Area.2. Models were assessed with R2, Bias, and RMSEP (Root Mean Squared Error of Prediction). The results showed that almost all models were validated with high R2 values, indicating that these digital phenotypes can be useful to rank plant biomass on a relative basis. However, in many occasions when accurate prediction of plant biomass is needed, it is important for researchers to know that models that relate image-based phenotypes to plant biomass should be carefully constructed. Our results show that the range of plant size and the genotypic diversity of the calibration sets in relation to the validation sets have large impact on the model accuracy. Large maize plants cause systematic bias as they grow toward the top-view camera. Excluding top-view images from modeling can there benefit modeling for the experiments involving large maize plants.

  12. Lattice Boltzmann modeling of directional wetting: comparing simulations to experiments.

    PubMed

    Jansen, H Patrick; Sotthewes, Kai; van Swigchem, Jeroen; Zandvliet, Harold J W; Kooij, E Stefan

    2013-07-01

    Lattice Boltzmann Modeling (LBM) simulations were performed on the dynamic behavior of liquid droplets on chemically striped patterned surfaces, ultimately with the aim to develop a predictive tool enabling reliable design of future experiments. The simulations accurately mimic experimental results, which have shown that water droplets on such surfaces adopt an elongated shape due to anisotropic preferential spreading. Details of the contact line motion such as advancing of the contact line in the direction perpendicular to the stripes exhibit pronounced similarities in experiments and simulations. The opposite of spreading, i.e., evaporation of water droplets, leads to a characteristic receding motion first in the direction parallel to the stripes, while the contact line remains pinned perpendicular to the stripes. Only when the aspect ratio is close to unity, the contact line also starts to recede in the perpendicular direction. Very similar behavior was observed in the LBM simulations. Finally, droplet movement can be induced by a gradient in surface wettability. LBM simulations show good semiquantitative agreement with experimental results of decanol droplets on a well-defined striped gradient, which move from high- to low-contact angle surfaces. Similarities and differences for all systems are described and discussed in terms of the predictive capabilities of LBM simulations to model direction wetting. PMID:23944550

  13. Modeling of Carbon Migration During JET Injection Experiments

    SciTech Connect

    Strachan, J. D.; Likonen, J.; Coad, P.; Rubel, M.; Widdowson, A.; Airila, M.; Andrew, P.; Brezinsek, S.; Corrigan, G.; Esser, H. G.; Jachmich, S.; Kallenbach, A.; Kirschner, A.; Kreter, A.; Matthews, G. F.; Philipps, V.; Pitts, R. A.; Spence, J.; Stamp, M.; Wiesen, S.

    2008-10-15

    JET has performed two dedicated carbon migration experiments on the final run day of separate campaigns (2001 and 2004) using {sup 13}CH{sub 4} methane injected into repeated discharges. The EDGE2D/NIMBUS code modelled the carbon migration in both experiments. This paper describes this modelling and identifies a number of important migration pathways: (1) deposition and erosion near the injection location, (2) migration through the main chamber SOL, (3) migration through the private flux region aided by E x B drifts, and (4) neutral migration originating near the strike points. In H-Mode, type I ELMs are calculated to influence the migration by enhancing erosion during the ELM peak and increasing the long-range migration immediately following the ELM. The erosion/re-deposition cycle along the outer target leads to a multistep migration of {sup 13}C towards the separatrix which is called 'walking'. This walking created carbon neutrals at the outer strike point and led to {sup 13}C deposition in the private flux region. Although several migration pathways have been identified, quantitative analyses are hindered by experimental uncertainty in divertor leakage, and the lack of measurements at locations such as gaps and shadowed regions.

  14. Modeling and Analysis of AGS (1998) Thermal Shock Experiments

    SciTech Connect

    Haines, J.R.; Kim, S.H.; Taleyarkhan, R.P.

    1999-11-14

    An overview is provided on modeling and analysis of thermal shock experiments conducted during 1998 with high-energy, short-pulse energy deposition in a mercury filled container in the Alternating Gradient Synchrotron (AGS) facility at Brookhaven National Laboratory (BNL). The simulation framework utilized along with the results of simulations for pressure and strain profiles are presented. While the magnitude of penk strain predictions versus data are in reasonable agreement, the temporal variations were found to differ significantly in selected cases, indicating lack of modeling of certain physical phenomena or due to uncertainties in the experimental data gathering techniques. Key thermal-shock related issues and uncertainties are highlighted. Specific experiments conducted at BNL's AGS facility during 1998 (the subject of this paper) involved high-energy (24 GeV) proton energy deposition in the mercury target over a time frame of - 0.1s. The target consisted of an - 1 m. long cylindrical stainless steel shell with a hemispherical dome at the leading edge. It was filled with mercury at room temperature and pressure. Several optical strain gages were attached to the surface of the steel target. Figure 1 shows a schematic representation of the test vessel along with the main dimensions and positions of three optical strain gages at which meaningful data were obtained. As

  15. Evaporation of J13 water: laboratory experiments and geochemical modeling

    SciTech Connect

    Dibley, M.J.; Knauss, K.G.; Rosenberg, N.D.

    1999-08-11

    We report results from experiments on the evaporative chemical evolution of synthetic J13 water, representative of water from well J13, a common reference water in the Yucca Mountain Project. Data include anion and cation analysis and qualitative mineral identification for a series of open system experiments, with and without crushed tuff present, conducted at sub-boiling temperatures. Ca and Mg precipitated readily as carbonates and anions Cl, F, NO{sub 3} and SO{sub 4} remained in solution in nearly identical ratios. The pH stabilized at about 10. After {approx} 1000x concentration, the minerals formed were amorphous silica, aragonite and calcite. The presence of tuff appears to have very little effect on the relative distribution of the anions in solution, except for possibly F, which had a relatively lower concentration ratio. The Si was lower in the solutions with tuff present suggesting that the tuff enhances SiO{sub 2} precipitation. Even though the tools to model highly-concentrated salt solutions are limited, we compare our experimental results with the results of geochemical models, with (perhaps) surprising good results. In response to different assumed CO{sub 2} levels, pH varied, but anion concentrations were not greatly affected.

  16. Anomalous reactive transport in porous media: Experiments and modeling

    NASA Astrophysics Data System (ADS)

    Edery, Yaniv; Dror, Ishai; Scher, Harvey; Berkowitz, Brian

    2015-05-01

    We analyze dynamic behavior of chemically reactive species in a porous medium, subject to anomalous transport. In this context, we present transport experiments in a refraction-index-matched, three-dimensional, water-saturated porous medium. A pH indicator (Congo red) was used as either a conservative or a reactive tracer, depending on the tracer solution pH relative to that of the background solution. The porous medium consisted of an acrylic polymer material formed as spherical beads that have pH-buffering capacity. The magnitude of reaction during transport through the porous medium was related to the color change of the Congo red, via image analysis. Here, we focused on point injection of the tracer into a macroscopically uniform flow field containing water at a pH different from that of the injected tracer. The setup yielded measurements of the temporally evolving spatial (local-in-space) concentration field. Parallel experiments with the same tracer, but without reactions (no changes in pH), enabled identification of the transport itself to be anomalous (non-Fickian); this was quantified by a continuous time random walk (CTRW) formulation. A CTRW particle tracking model was then used to quantify the spatial and temporal migration of both the conservative and reactive tracer plumes. Model parameters related to the anomalous transport were determined from the conservative tracer experiments. An additional term accounting for chemical reaction was established solely from analysis of the reactant concentrations, and significantly, no other fitting parameters were required. The measurements and analysis emphasized the localized nature of reaction, caused by small-scale concentration fluctuations and preferential pathways. In addition, a threshold radius for pH-controlled reactive transport processes was defined under buffering conditions, which delineated the region in which reactions occurred rapidly.

  17. Space Weathering of Olivine: Samples, Experiments and Modeling

    NASA Technical Reports Server (NTRS)

    Keller, L. P.; Berger, E. L.; Christoffersen, R.

    2016-01-01

    Olivine is a major constituent of chondritic bodies and its response to space weathering processes likely dominates the optical properties of asteroid regoliths (e.g. S- and many C-type asteroids). Analyses of olivine in returned samples and laboratory experiments provide details and insights regarding the mechanisms and rates of space weathering. Analyses of olivine grains from lunar soils and asteroid Itokawa reveal that they display solar wind damaged rims that are typically not amorphized despite long surface exposure ages, which are inferred from solar flare track densities (up to 10 (sup 7 y)). The olivine damaged rim width rapidly approaches approximately 120 nm in approximately 10 (sup 6 y) and then reaches steady-state with longer exposure times. The damaged rims are nanocrystalline with high dislocation densities, but crystalline order exists up to the outermost exposed surface. Sparse nanophase Fe metal inclusions occur in the damaged rims and are believed to be produced during irradiation through preferential sputtering of oxygen from the rims. The observed space weathering effects in lunar and Itokawa olivine grains are difficult to reconcile with laboratory irradiation studies and our numerical models that indicate that olivine surfaces should readily blister and amorphize on relatively short time scales (less than 10 (sup 3 y)). These results suggest that it is not just the ion fluence alone, but other variable, the ion flux that controls the type and extent of irradiation damage that develops in olivine. This flux dependence argues for caution in extrapolating between high flux laboratory experiments and the natural case. Additional measurements, experiments, and modeling are required to resolve the discrepancies among the observations and calculations involving solar wind processing of olivine.

  18. Blast Loading Experiments of Developed Surrogate Models for TBI Scenarios

    NASA Astrophysics Data System (ADS)

    Alley, Matthew; Son, Steven

    2009-06-01

    This study aims to characterize the interaction of explosive blast waves through simulated anatomical systems. We have developed physical models and a systematic approach for testing traumatic brain injury (TBI) mechanisms and occurrences. A simplified series of models consisting of spherical PMMA shells followed by SLA prototyped skulls housing synthetic gelatins as brain simulants have been utilized. A series of experiments was conducted with the simple geometries to compare the sensitivity of the system response to mechanical properties of the simulants under high strain-rate explosive blasts. Small explosive charges were directed at the models to produce a realistic blast wave in a scaled laboratory setting. Blast profiles were measured and analyzed to compare system response severity. High-speed shadowgraph imaging captured blast wave interaction with the head model while particle tracking captured internal response for displacement and strain correlation. The results suggest amplification of shock waves inside the head due to impedance mismatches. Results from the strain correlations added to the theory of internal shearing between tissues.

  19. Experience and extensions to the ASM2 family of models.

    PubMed

    Dudley, J; Buck, G; Ashley, R; Jack, A

    2002-01-01

    The development of ASM2 has created a complex model for biological phosphorus removal. Most of the published work on calibrating this model has focused on the design of experiments to maximise information with which to calibrate the model, or the use of hourly data collected around and within an aeration tank. But many sewage works do not collect such data, nor have such instrumentation. The application of ASM2 with sparse data collected at a low frequency, and mostly only input-output, is considered in this paper, based on data collected at a Swedish sewage works. This paper shows that ASM2 can be calibrated with such measurements. This paper also looks at a modification to ASM2d to better handle heterotrophic usage of volatile fatty acids, and the use of this model to study the effects of large increases in in-sewer storage on sewage treatment works. Concern about the generation of large quantities of VFAs, and their effect on the sewage treatment processes, was unfounded. PMID:11989871

  20. Stress corrosion cracking of metal matrix composites: Modeling and experiment

    SciTech Connect

    Jones, R.H.

    1990-10-01

    The stress corrosion crack growth ate of metal matrix composites has been described by a model which is dependent on the length-to- diameter ({ell}/d) ratio and volume fraction of the reinforcing phase and matrix creep component. The model predicts a large dependence of the stress corrosion crack growth rate of a metal matrix composite on {ell}/d and matrix creep component and a small dependence on the volume fraction of reinforcement. Experimentally determined crack growth rates for 7090 Al/SiC tested in 3.5% NcCl solution, 6061 Al/SiC tested in moist air with NaCl and immersed in NaCl solution, and Mg/Al{sub 2}0{sub 3} tested in a chloride/chromate solution are all consistent with the model. The close correspondence between the model and experiment for a matrix creep stress exponent of 3 suggest that there is little corrosion damage to the reinforcing phase in these systems. 16 refs., 5 figs.

  1. Real-data Calibration Experiments On A Distributed Hydrologic Model

    NASA Astrophysics Data System (ADS)

    Brath, A.; Montanari, A.; Toth, E.

    The increasing availability of extended information on the study watersheds does not generally overcome the need for the determination through calibration of at least a part of the parameters of distributed hydrologic models. The complexity of such models, making the computations highly intensive, has often prevented an extensive analysis of calibration issues. The purpose of this study is an evaluation of the validation results of a series of automatic calibration experiments (using the shuffled complex evolu- tion method, Duan et al., 1992) performed with a highly conceptualised, continuously simulating, distributed hydrologic model applied on the real data of a mid-sized Ital- ian watershed. Major flood events occurred in the 1990-2000 decade are simulated with the parameters obtained by the calibration of the model against discharge data observed at the closure section of the watershed and the hydrological features (overall agreement, volumes, peaks and times to peak) of the discharges obtained both in the closure and in an interior stream-gauge are analysed for validation purposes. A first set of calibrations investigates the effect of the variability of the calibration periods, using the data from several single flood events and from longer, continuous periods. Another analysis regards the influence of rainfall input and it is carried out varying the size and distribution of the raingauge network, in order to examine the relation between the spatial pattern of observed rainfall and the variability of modelled runoff. Lastly, a comparison of the hydrographs obtained for the flood events with the model parameterisation resulting when modifying the objective function to be minimised in the automatic calibration procedure is presented.

  2. Striving for safety in fresh and fresh-cut fruits and vegetables

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Consumption of fresh produce is a central component of a healthy diet. However, contamination of leafy greens, tomatoes, cantaloupes and other fresh and fresh-cut fruits and vegetables with human pathogens is a source of ongoing concern for consumers. Industry and regulators have worked together to ...

  3. CFD Simulation of the distribution of ClO2 in fresh produce to improve safety

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The shelf life of fresh-cut produce may be prolonged with the injection of bactericide gases like chlorine dioxide (ClO2). A comparative study has been conducted by modeling the injection of three different gases, CO2, ClO2 and N2 inside a PET clamshell containers commonly use to package fresh produ...

  4. DIETARY FIBER CONTENT IN FRESH CITRUS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is a wide variation in the reported values for pectin and dietary fiber content in the edible portions of fresh orange and grapefruit. Two studies done by the Produce Marketing Association in 1990 reported 4.0 g dietary fiber/ 100 g of fresh edible grapefruit and 4.4 g dietary fiber / 100 g f...

  5. DISPERSIBILITY OF CRUDE OIL IN FRESH WATER

    EPA Science Inventory

    The effects of surfactant composition on the ability of chemical dispersants to disperse crude oil in fresh water were investigated. The objective of this research was to determine whether effective fresh water dispersants can be designed in case this technology is ever consider...

  6. Microbial Safety of Fresh Produce - Preface

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fresh produce has been the source of recent outbreaks of foodborne illness which have caused sickness, hospitalizations and deaths of consumers, as well as serious adverse economic impact on growers and processors. The preface for the book entitled “Microbial Safety of Fresh Produce” discusses possi...

  7. [A method for assessing the total viable count of fresh meat based on hyperspectral scattering technique].

    PubMed

    Song, Yu-Lin; Peng, Yan-Kun; Guo, Hui; Zhang, Lei-Lei; Zhao, Juan

    2014-03-01

    The objective of this study is to develop a hyperspectral imaging system to predict the bacteria total viable count in fresh pork. The hyperspectral scattering data were curvefitted by different fitting methods, and correlation differences of models were compared based on the bacteria total viable count of fresh pork, thus providing modeling basis of device for future study. Total 63 fresh pork samples which was used in the experiment were stored at 4 degrees C in the refrigerator of constant temperature. Experiment was performed everyday for 15 days. 4 or 5 random samples were used each day for the experiment. Hyperspectral scattering images and spectral scattering optical data in the wavelength region of 400 to 1 100 nm were acquired from the surface of all of the pork samples. Lorentz and Gompertz function and the modified function was applied to fit the scattering profiles of pork samples. Different parameters could be obtained by Lorentz and Gompertz fitting and the modified function fitting. The different parameters could represent the optical characteristic of the scattering profiles. The standard values of the bacteria total viable count of pork were obtained by classical microbiological plating methods. Because the standard value of the bacteria total viable count was big, log10 of the bacteria total viable count obtained by classical microbiological plating was used to simplify the calculation. Both individual parameters and integrated parameters were explored to develop the models. The multi-linear regression statistical approach was used to establish the models for predicting pork the bacteria total viable count. Both Lorentz and Gompertz function and the modified function included three and four parameters formula. The results showed that correlation coefficient of the models is higher with Lorentz three parameters combination, Lorentz four parameters combination and Gompertz four parameters combination than the individual parameters and other two or

  8. Modeling of Thermal-Hydrological-Chemical Laboratory Experiments

    SciTech Connect

    P. F. Dobson; T. J. Kneafsey; E. L. Sonnenthal; Nicolas Spycher

    2001-05-31

    The emplacement of heat-generating nuclear waste in the potential geologic repository at Yucca Mountain, Nevada, will result in enhanced water-rock interaction around the emplacement drifts. Water present in the matrix and fractures of the rock around the drift may vaporize and migrate via fractures to cooler regions where condensation would occur. The condensate would react with the surrounding rock, resulting in mineral dissolution. Mineralized water flowing under gravity back towards the heat zone would boil, depositing the dissolved minerals. Such mineral deposition would reduce porosity and permeability above the repository, thus altering the flow paths of percolating water. The objective of this research is to use coupled thermal-hydrological-chemical (THC) models to simulate previously conducted laboratory experiments involving tuff dissolution and mineral precipitation in a boiling, unsaturated fracture. Numerical simulations of tuff dissolution and fracture plugging were performed using a modified version of the TOUGHREACT code developed at LBNL by T. Xu and K. Pruess. The models consider the transport of heat, water, gas and dissolved constituents, reactions between gas, mineral and aqueous phases, and the coupling of porosity and permeability to mineral dissolution and precipitation. The model dimensions and initial fluid chemistry, rock mineralogy, permeability, and porosity were defined using the experimental conditions. A 1-D plug-flow model was used to simulate dissolution resulting from reaction between deionized water and crushed ash flow tuff. A 2-D model was developed to simulate the flow of mineralized water through a planar fracture within a block of ash flow tuff where boiling conditions led to mineral precipitation. Matrix blocks were assigned zero permeability to confine fluid flow to the fracture, and permeability changes in the fracture were specified using the porosity cubic law relationship.

  9. The Mechanics of Neutrophils: Synthetic Modeling of Three Experiments

    PubMed Central

    Herant, Marc; Marganski, William A.; Dembo, Micah

    2003-01-01

    Much experimental data exist on the mechanical properties of neutrophils, but so far, they have mostly been approached within the framework of liquid droplet models. This has two main drawbacks: 1), It treats the cytoplasm as a single phase when in reality, it is a composite of cytosol and cytoskeleton; and 2), It does not address the problem of active neutrophil deformation and force generation. To fill these lacunae, we develop here a comprehensive continuum-mechanical paradigm of the neutrophil that includes proper treatment of the membrane, cytosol, and cytoskeleton components. We further introduce two models of active force production: a cytoskeletal swelling force and a polymerization force. Armed with these tools, we present computer simulations of three classic experiments: the passive aspiration of a neutrophil into a micropipette, the active extension of a pseudopod by a neutrophil exposed to a local stimulus, and the crawling of a neutrophil inside a micropipette toward a chemoattractant against a varying counterpressure. Principal results include: 1), Membrane cortical tension is a global property of the neutrophil that is affected by local area-increasing shape changes. We argue that there exists an area dilation viscosity caused by the work of unfurling membrane-storing wrinkles and that this viscosity is responsible for much of the regulation of neutrophil deformation. 2), If there is no swelling force of the cytoskeleton, then it must be endowed with a strong cohesive elasticity to prevent phase separation from the cytosol during vigorous suction into a capillary tube. 3), We find that both swelling and polymerization force models are able to provide a unifying fit to the experimental data for the three experiments. However, force production required in the polymerization model is beyond what is expected from a simple short-range Brownian ratchet model. 4), It appears that, in the crawling of neutrophils or other amoeboid cells inside a micropipette

  10. Model Evaluation and Hindcasting: An Experiment with an Integrated Assessment Model

    SciTech Connect

    Chaturvedi, Vaibhav; Kim, Son H.; Smith, Steven J.; Clarke, Leon E.; Zhou, Yuyu; Kyle, G. Page; Patel, Pralit L.

    2013-11-01

    Integrated assessment models have been extensively used for analyzing long term energy and greenhouse emissions trajectories and have influenced key policies on this subject. Though admittedly these models are focused on the long term trajectories, how well these models are able to capture historical dynamics is an open question. In a first experiment of its kind, we present a framework for evaluation of such integrated assessment models. We use Global Change Assessment Model for this zero order experiment, and focus on the building sector results for USA. We calibrate the model for 1990 and run it forward up to 2095 in five year time steps. This gives us results for 1995, 2000, 2005 and 2010 which we compare to observed historical data at both fuel level and service level. We focus on bringing out the key insights for the wider process of model evaluation through our experiment with GCAM. We begin with highlighting that creation of an evaluation dataset and identification of key evaluation metric is the foremost challenge in the evaluation process. Our analysis highlights that estimation of functional form of the relationship between energy service demand, which is an unobserved variable, and its drivers is a significant challenge in the absence of adequate historical data for both the dependent and driver variables. Historical data availability for key metrics is a serious limiting factor in the process of evaluation. Interestingly, service level data against which such models need to be evaluated are itself a result of models. Thus for energy services, the best we can do is compare our model results with other model results rather than observed and measured data. We show that long term models, by the nature of their construction, will most likely underestimate the rapid growth in some services observed in a short time span. Also, we learn that modeling saturated energy services like space heating is easier than modeling unsaturated services like space cooling

  11. Atmospheric Climate Model Experiments Performed at Multiple Horizontal Resolutions

    SciTech Connect

    Phillips, T; Bala, G; Gleckler, P; Lobell, D; Mirin, A; Maxwell, R; Rotman, D

    2007-12-21

    This report documents salient features of version 3.3 of the Community Atmosphere Model (CAM3.3) and of three climate simulations in which the resolution of its latitude-longitude grid was systematically increased. For all these simulations of global atmospheric climate during the period 1980-1999, observed monthly ocean surface temperatures and sea ice extents were prescribed according to standard Atmospheric Model Intercomparison Project (AMIP) values. These CAM3.3 resolution experiments served as control runs for subsequent simulations of the climatic effects of agricultural irrigation, the focus of a Laboratory Directed Research and Development (LDRD) project. The CAM3.3 model was able to replicate basic features of the historical climate, although biases in a number of atmospheric variables were evident. Increasing horizontal resolution also generally failed to ameliorate the large-scale errors in most of the climate variables that could be compared with observations. A notable exception was the simulation of precipitation, which incrementally improved with increasing resolution, especially in regions where orography plays a central role in determining the local hydroclimate.

  12. Model experiments on the 100,000-yr glacial cycle

    NASA Astrophysics Data System (ADS)

    Oerlemans, J.

    1980-10-01

    It is believed that during the Quaternary era changes in global ice volume were mainly due to changes in the size of the ice sheets on the Eurasian and American continents. Time spectra of oxygen isotope records from deep-sea cores and of the Earth's orbital parameters are remarkably similar in the 10,000-120,000-yr range1,2, suggesting that changes in global ice volume are forced by insolation variations. Model studies by Weertman3,4 and Pollard5 have confirmed this point to some extent: the 20,000- and 40,000-yr cycles can be reproduced, but the 100,000-yr cycle does not show up. Recently, Imbrie and Imbrie6 have fitted simple nonlinear mathematical models to δ18O curves. They found that reasonable fits are obtained if the time scale for ice-sheet growth is about 27,000 yr and for decay about 7,000 yr. The present study considers the problem of the 100,000-yr cycle in a similar way. Experiments with a Northern Hemisphere ice-sheet model show that the 100,000-yr cycle and its sawtooth shape may be explained by ice sheet/bedrock dynamics alone. This cycle seems to be an internally generated feature and is not forced by variations in the eccentricity of the Earth's orbit.

  13. Laboratory photoionized plasma experiments at Z - Comparison with modeling

    NASA Astrophysics Data System (ADS)

    Mayes, D.; Lockard, T.; Durmaz, T.; Hall, I.; Mancini, R.; Bailey, J.; Rochau, G.; Loisel, G.; Heeter, R.; Liedahl, D.

    2013-10-01

    Photoionized plasmas are common in astrophysical environments, such as x-ray binaries and active galactic nuclei. We discuss an experimental and modeling effort to study the atomic kinetics in plasmas of this type via K-shell line absorption spectroscopy. Results from a first pass thru our 2nd-generation dataset are compared with results of several modeling codes attempting to simulate our experimental conditions. The experiment employs the intense x-ray flux emitted by the collapse of a z-pinch to produce and backlight a Neon photoionized plasma in a cm-scale gas cell at various distances from the z-pinch. The filling pressure is monitored in situ providing the plasma particle number density. High-resolution spectra from a TREX spectrometer are processed with a suite of specially designed IDL tools to produce transmission spectra, which show absorption in several ionization stages of Neon. Analysis independent of atomic kinetics calculations yields the charge state distribution and ion areal densities used to benchmark atomic kinetics codes. In addition, the electron temperature, extracted from a level population ratio, is used to test heating models. This work is sponsored in part by the National Nuclear Security Administration under the High Energy Density Laboratory Plasmas grant program through DOE Grant DE-FG52-09NA29551, and the Z Facility Fundamental Science Program of SNL.

  14. Edge effect modeling and experiments on active lap processing.

    PubMed

    Liu, Haitao; Wu, Fan; Zeng, Zhige; Fan, Bin; Wan, Yongjian

    2014-05-01

    Edge effect is regarded as one of the most difficult technical issues for fabricating large primary mirrors, especially for large polishing tools. Computer controlled active lap (CCAL) uses a large size pad (e.g., 1/3 to 1/5 workpiece diameters) to grind and polish the primary mirror. Edge effect also exists in the CCAL process in our previous fabrication. In this paper the material removal rules when edge effects happen (i.e. edge tool influence functions (TIFs)) are obtained through experiments, which are carried out on a Φ1090-mm circular flat mirror with a 375-mm-diameter lap. Two methods are proposed to model the edge TIFs for CCAL. One is adopting the pressure distribution which is calculated based on the finite element analysis method. The other is building up a parametric equivalent pressure model to fit the removed material curve directly. Experimental results show that these two methods both effectively model the edge TIF of CCAL. PMID:24921777

  15. Comparing models of contrast gain using psychophysical experiments.

    PubMed

    DiMattina, Christopher

    2016-07-01

    In a wide variety of neural systems, neurons tuned to a primary dimension of interest often have responses that are modulated in a multiplicative manner by other features such as stimulus intensity or contrast. In this methodological study, we present a demonstration that it is possible to use psychophysical experiments to compare competing hypotheses of multiplicative gain modulation in a neural population, using the specific example of contrast gain modulation in orientation-tuned visual neurons. We demonstrate that fitting biologically interpretable models to psychophysical data yields physiologically accurate estimates of contrast tuning parameters and allows us to compare competing hypotheses of contrast tuning. We demonstrate a powerful methodology for comparing competing neural models using adaptively generated psychophysical stimuli and demonstrate that such stimuli can be highly effective for distinguishing qualitatively similar hypotheses. We relate our work to the growing body of literature that uses fits of neural models to behavioral data to gain insight into neural coding and suggest directions for future research. PMID:27380470

  16. Global discharge modelling experiments with the TIGGE archive

    NASA Astrophysics Data System (ADS)

    Zsoter, Ervin; Smith, Paul; Dutra, Emanuel; Pappenberger, Florian; Wetterhall, Fredrik; Bogner, Konrad; Balsamo, Gianpaolo; Richardson, David; Di Giuseppe, Francesca

    2015-04-01

    In this study we derived and analysed global ensemble discharge forecasts for TIGGE (THORPEX Interactive Grand Global Ensemble) models using the modelling and technical infrastructure available at ECMWF. We focussed on the global characteristics of discharge with special emphasis on the analysis of errors stemming from different segments of the production system and also on the post-processing possibilities of the data. The modelling work was based on the HTESSEL (Hydrology-Tiled ECMWF Scheme for Surface Exchange over Land) land-surface model used operationally at ECMWF. The offline version of HTESSEL was extended to accommodate ensemble forecast runs from TIGGE and the climate and initial conditions were taken from ERA Interim. Finally the model output runoff was coupled to the CaMa-Flood distributed global river routing model to provide river discharge. The initial state of the river network for the routing was provided by 30-year ERA Interim HTESSEL integration coupled with CaMa-Flood. The production of the daily discharge forecasts up to 10 days covered the period 2008-2013 for four TIGGE models (ECMWF, UKMO, NCEP and CMA) for about 400 global river catchments with upstream area over 40000 km2. The impact of the HTESSEL atmospheric forcing on the discharge was investigated as it played a crucial role in the experiments. The sensitivity analysis to the forcing parameter choices showed some interesting behaviour in the impact of wind, radiation, temperature, humidity and precipitation on the global discharge forecasts. The positive influence of the improved ERA Interim precipitation forcing (GPCP v2.0 corrected) on the quality of the initial river flow in the forecast routing was also highlighted. To help interpreting the discharge performance two of the HTESSEL atmospheric forcing parameters, 2m temperature and 24-hour total precipitation were verified and the performance characteristics explored using four TIGGE models and the equal weight multi-model

  17. Computer modeling of active experiments in space plasmas

    NASA Astrophysics Data System (ADS)

    Bollens, Ross John

    1993-01-01

    Our understanding of space plasmas is expanding rapidly. This is, in large part, due to the ambitious efforts of scientists from around the world who are performing large scale active experiments in the space plasma surrounding the earth. One such effort was designated the Active Magnetospheric Particle Tracer Explorers (AMPTE) and consisted of a series of plasma releases that were completed during 1984 and 1985. What makes the AMPTE experiments particularly interesting was the occurrence of a dramatic anomaly that was completely unpredicted. During the AMPTE experiment, three satellites traced the solar wind flow into the earth's magnetosphere. One satellite, built by West Germany, released a series of barium and lithium canisters that were detonated and subsequently photoionized via solar radiation, thereby creating an artificial comet. Another satellite, built by Great Britain and in the vicinity during detonation, carried, as did the first satellite, a comprehensive set of magnetic field, particle, and wave instruments. Upon detonation, what was observed by the satellites, as well as by aircraft and ground-based observers, was quite unexpected. The initial deflection of the ion clouds was not in the ambient solar wind's flow direction (V) but rather in the direction transverse to the solar wind and the background magnetic field (V x B). This result was not predicted by any existing theories or simulation models; it is the main subject discussed in this dissertation. A large three dimensional computer simulation was produced to demonstrate that this transverse motion can be explained in terms of a rocket effect. Due to the extreme computer resources utilized in producing this work, the computer methods used to complete the calculation and the visualization techniques used to view the results are also discussed.

  18. Model Experiment on the Generation of the Korotkoff Sounds

    NASA Astrophysics Data System (ADS)

    Arakawa, Mieko

    1980-07-01

    The mechanism of the genesis of the Korotkoff sounds is investigated by model experiment using latex tubes and a segment of isolated blood vessel of dogs. The tube compliance is much reduced when the transmural (internal minus external) pressure is very high or very low, and increases radically for intermediate states. It can be concluded that there are two different mechanisms by which the sounds are emitted. One is durable sounds caused by self-excited vibration in the process of collapse of the tube, and the other is impulsive sounds emitted transiently when the tube compliance is abruptly decreased. It is possible to explain qualitatively the change of sound phases over a wide range from systole to diastole as an appropriate mixture of durable and impulsive sounds.

  19. Electrostatic Model Applied to ISS Charged Water Droplet Experiment

    NASA Technical Reports Server (NTRS)

    Stevenson, Daan; Schaub, Hanspeter; Pettit, Donald R.

    2015-01-01

    The electrostatic force can be used to create novel relative motion between charged bodies if it can be isolated from the stronger gravitational and dissipative forces. Recently, Coulomb orbital motion was demonstrated on the International Space Station by releasing charged water droplets in the vicinity of a charged knitting needle. In this investigation, the Multi-Sphere Method, an electrostatic model developed to study active spacecraft position control by Coulomb charging, is used to simulate the complex orbital motion of the droplets. When atmospheric drag is introduced, the simulated motion closely mimics that seen in the video footage of the experiment. The electrostatic force's inverse dependency on separation distance near the center of the needle lends itself to analytic predictions of the radial motion.

  20. Development of Supersonic Combustion Experiments for CFD Modeling

    NASA Technical Reports Server (NTRS)

    Baurle, Robert; Bivolaru, Daniel; Tedder, Sarah; Danehy, Paul M.; Cutler, Andrew D.; Magnotti, Gaetano

    2007-01-01

    This paper describes the development of an experiment to acquire data for developing and validating computational fluid dynamics (CFD) models for turbulence in supersonic combusting flows. The intent is that the flow field would be simple yet relevant to flows within hypersonic air-breathing engine combustors undergoing testing in vitiated-air ground-testing facilities. Specifically, it describes development of laboratory-scale hardware to produce a supersonic combusting coaxial jet, discusses design calculations, operability and types of flames observed. These flames are studied using the dual-pump coherent anti- Stokes Raman spectroscopy (CARS) - interferometric Rayleigh scattering (IRS) technique. This technique simultaneously and instantaneously measures temperature, composition, and velocity in the flow, from which many of the important turbulence statistics can be found. Some preliminary CARS data are presented.

  1. Ignition and Growth Modeling of LX-17 Hockey Puck Experiments

    SciTech Connect

    Tarver, C M

    2004-04-19

    Detonating solid plastic bonded explosives (PBX) formulated with the insensitive molecule triaminotrinitrobenzene (TATB) exhibit measurable reaction zone lengths, curved shock fronts, and regions of failing chemical reaction at abrupt changes in the charge geometry. A recent set of ''hockey puck'' experiments measured the breakout times of diverging detonation waves in ambient temperature LX-17 (92.5 % TATB plus 7.5% Kel-F binder) and the breakout times at the lower surfaces of 15 mm thick LX-17 discs placed below the detonator-booster plane. The LX-17 detonation waves in these discs grow outward from the initial wave leaving regions of unreacted or partially reacted TATB in the corners of these charges. This new experimental data is accurately simulated for the first time using the Ignition and Growth reactive flow model for LX-17, which is normalized to a great deal of detonation reaction zone, failure diameter and diverging detonation data. A pressure cubed dependence for the main growth of reaction rate yields excellent agreement with experiment, while a pressure squared rate diverges too quickly and a pressure quadrupled rate diverges too slowly in the LX-17 below the booster equatorial plane.

  2. Representing plants as rigid cylinders in experiments and models

    NASA Astrophysics Data System (ADS)

    Vargas-Luna, Andrés; Crosato, Alessandra; Calvani, Giulio; Uijttewaal, Wim S. J.

    2016-07-01

    Simulating the morphological adaptation of water systems often requires including the effects of plants on water and sediment dynamics. Physical and numerical models need representing vegetation in a schematic easily-quantifiable way despite the variety of sizes, shapes and flexibility of real plants. Common approaches represent plants as rigid cylinders, but the ability of these schematizations to reproduce the effects of vegetation on morphodynamic processes has never been analyzed systematically. This work focuses on the consequences of representing plants as rigid cylinders in laboratory tests and numerical simulations. New experiments show that the flow resistance decreases for increasing element Reynolds numbers for both plants and rigid cylinders. Cylinders on river banks can qualitatively reproduce vegetation effects on channel width and bank-related processes. A comparative review of numerical simulations shows that Baptist's method that sums the contribution of bed shear stress and vegetation drag, underestimates bed erosion within sparse vegetation in real rivers and overestimates the mean flow velocity in laboratory experiments. This is due to assuming uniform flow among plants and to an overestimation of the role of the submergence ratio.

  3. Numerically Modeling Pulsed-Current, Kinked Wire Experiments

    NASA Astrophysics Data System (ADS)

    Filbey, Gordon; Kingman, Pat

    1999-06-01

    The U.S. Army Research Laboratory (ARL) has embarked on a program to provide far-term land fighting vehicles with electromagnetic armor protection. Part of this work seeks to establish robust simulations of magneto-solid-mechanics phenomena. Whether describing violent rupture of a fuse link resulting from a large current pulse or the complete disruption of a copper shaped-charge jet subjected to high current densities, the simulations must include effects of intense Lorentz body forces and rapid Ohmic heating. Material models are required that describe plasticity, flow and fracture, conductivity, and equation of state (EOS) parameters for media in solid, liquid, and vapor phases. An extended version of the Eulerian wave code CTH has been used to predict the apex motion of a V-shaped (``kinked'') copper wire 3mm in diameter during a 400 kilo-amp pulse. These predictions, utilizing available material, EOS, and conductivity data for copper and the known characteristics of an existing capacitor-bank pulsed power supply, were then used to configure an experiment. The experiments were in excellent agreement with the prior simulations. Both computational and experimental results (including electrical data and flash X-rays) will be presented.

  4. Numerical Modelling of the Deep Impact Mission Experiment

    NASA Technical Reports Server (NTRS)

    Wuennemann, K.; Collins, G. S.; Melosh, H. J.

    2005-01-01

    NASA s Deep Impact Mission (launched January 2005) will provide, for the first time ever, insights into the interior of a comet (Tempel 1) by shooting a approx.370 kg projectile onto the surface of a comets nucleus. Although it is usually assumed that comets consist of a very porous mixture of water ice and rock, little is known about the internal structure and in particular the constitutive material properties of a comet. It is therefore difficult to predict the dimensions of the excavated crater. Estimates of the crater size are based on laboratory experiments of impacts into various target compositions of different densities and porosities using appropriate scaling laws; they range between 10 s of meters up to 250 m in diameter [1]. The size of the crater depends mainly on the physical process(es) that govern formation: Smaller sizes are expected if (1) strength, rather than gravity, limits crater growth; and, perhaps even more crucially, if (2) internal energy losses by pore-space collapse reduce the coupling efficiency (compaction craters). To investigate the effect of pore space collapse and strength of the target we conducted a suite of numerical experiments and implemented a novel approach for modeling porosity and the compaction of pores in hydrocode calculations.

  5. Representation of Thwaites Glacier Bed Uncertainty for Modeling Experiments

    NASA Astrophysics Data System (ADS)

    Jackson, C. S.; Goff, J. A.; Waibel, S.; Greene, C. A.; Johnson, J. V.; Young, D. A.; Blankenship, D. D.

    2013-12-01

    Thwaites catchment includes a landward sloping bed and a marine ice sheet. The sensitivity of this glacier to a warming ocean is likely dependent on specific details of its bed. Goff et al., (submitted to JGR Earth Surface) has created a conditional simulation of Thwaites Glacier bed that includes inhomogeneous statistics and channelized morphology that takes advantage of the high resolution inferences of bed geometry taken from flight paths of aerogeophysical surveys to make inferences of the type of features that are likely to exist between flight paths. This effort is now being extended to represent the uncertainties due to 1) off-nadir radar energy being interpreted inappropriately as being from bed features at nadir, 2) mischaracterization of roughness, 3) flight track spacing density, and 4) the failure to identify individual glacier carved channels. Estimates of the high-resolution bed (at 250 meter resolution) and its uncertainty will be compared against a so-called 'mass conserving' bed. The point of this effort is to capture the elements of the way ice-penetrating radar data is used to estimate ice thickness for use in modeling experiments where bed uncertainties are likely to play an important role. This exercise is interesting from an uncertainty quantification point of view insofar as while the actual uncertainties are high dimensional (i.e. every grid point that has not been observed directly), what matters to sea level rise experiments is some low-dimensional summary of what is important to glacier dynamics.

  6. Kinetic modeling of molecular motors: pause model and parameter determination from single-molecule experiments

    NASA Astrophysics Data System (ADS)

    Morin, José A.; Ibarra, Borja; Cao, Francisco J.

    2016-05-01

    Single-molecule manipulation experiments of molecular motors provide essential information about the rate and conformational changes of the steps of the reaction located along the manipulation coordinate. This information is not always sufficient to define a particular kinetic cycle. Recent single-molecule experiments with optical tweezers showed that the DNA unwinding activity of a Phi29 DNA polymerase mutant presents a complex pause behavior, which includes short and long pauses. Here we show that different kinetic models, considering different connections between the active and the pause states, can explain the experimental pause behavior. Both the two independent pause model and the two connected pause model are able to describe the pause behavior of a mutated Phi29 DNA polymerase observed in an optical tweezers single-molecule experiment. For the two independent pause model all parameters are fixed by the observed data, while for the more general two connected pause model there is a range of values of the parameters compatible with the observed data (which can be expressed in terms of two of the rates and their force dependencies). This general model includes models with indirect entry and exit to the long-pause state, and also models with cycling in both directions. Additionally, assuming that detailed balance is verified, which forbids cycling, this reduces the ranges of the values of the parameters (which can then be expressed in terms of one rate and its force dependency). The resulting model interpolates between the independent pause model and the indirect entry and exit to the long-pause state model

  7. Modeling of drive-symmetry experiments in gas-filled hohlraums at Nova

    SciTech Connect

    Lindman, E.L.; Magelssen, G.R.; Delamater, E.L.; Hauer, A.A.; Wilde, B.H.; Powers, L.V.; Murphy, T.J.; Pollaine, S.M.; Suter, L.J.

    1995-05-01

    Experiments on capsule implosions in gas-filled hohlraums have been carried out on the NOVA Laser at Lawrence Livermore National Laboratory. Observed capsule shapes are more oblate than predicted using modeling methods which agree well with experiments in evacuated hohlraums. Improvements in modeling required to calculate these experiments and additional experiments are being pursued.

  8. Recent Experiences in Aftershock Hazard Modelling in New Zealand

    NASA Astrophysics Data System (ADS)

    Gerstenberger, M.; Rhoades, D. A.; McVerry, G.; Christophersen, A.; Bannister, S. C.; Fry, B.; Potter, S.

    2014-12-01

    The occurrence of several sequences of earthquakes in New Zealand in the last few years has meant that GNS Science has gained significant recent experience in aftershock hazard and forecasting. First was the Canterbury sequence of events which began in 2010 and included the destructive Christchurch earthquake of February, 2011. This sequence is occurring in what was a moderate-to-low hazard region of the National Seismic Hazard Model (NSHM): the model on which the building design standards are based. With the expectation that the sequence would produce a 50-year hazard estimate in exceedance of the existing building standard, we developed a time-dependent model that combined short-term (STEP & ETAS) and longer-term (EEPAS) clustering with time-independent models. This forecast was combined with the NSHM to produce a forecast of the hazard for the next 50 years. This has been used to revise building design standards for the region and has contributed to planning of the rebuilding of Christchurch in multiple aspects. An important contribution to this model comes from the inclusion of EEPAS, which allows for clustering on the scale of decades. EEPAS is based on three empirical regressions that relate the magnitudes, times of occurrence, and locations of major earthquakes to regional precursory scale increases in the magnitude and rate of occurrence of minor earthquakes. A second important contribution comes from the long-term rate to which seismicity is expected to return in 50-years. With little seismicity in the region in historical times, a controlling factor in the rate is whether-or-not it is based on a declustered catalog. This epistemic uncertainty in the model was allowed for by using forecasts from both declustered and non-declustered catalogs. With two additional moderate sequences in the capital region of New Zealand in the last year, we have continued to refine our forecasting techniques, including the use of potential scenarios based on the aftershock

  9. Anomalous transport in fracture networks: field scale experiments and modelling

    NASA Astrophysics Data System (ADS)

    Kang, P. K.; Le Borgne, T.; Bour, O.; Dentz, M.; Juanes, R.

    2012-12-01

    Anomalous transport is widely observed in different settings and scales of transport through porous and fractured geologic media. A common signature of anomalous transport is the late-time power law tailing in breakthrough curves (BTCs) during tracer tests. Various conceptual models of anomalous transport have been proposed, including multirate mass transfer, continuous time random walk, and stream tube models. Since different conceptual models can produce equally good fits to a single BTC, tracer test interpretation has been plagued with ambiguity. Here, we propose to resolve such ambiguity by analyzing BTCs obtained from both convergent and push-pull flow configurations at two different fracture planes. We conducted field tracer tests in a fractured granite formation close to Ploemeur, France. We observe that BTC tailing depends on the flow configuration and the injection fracture. Specifically the tailing disappears under push-pull geometry, and when we injected at a fracture with high flux (Figure 1). This indicates that for this fractured granite, BTC tailing is controlled by heterogeneous advection and not by matrix diffusion. To explain the change in tailing behavior for different flow configurations, we employ a simple lattice network model with heterogeneous conductivity distribution. The model assigns random conductivities to the fractures and solves the Darcy equation for an incompressible fluid, enforcing mass conservation at fracture intersections. The mass conservation constraint yields a correlated random flow through the fracture system. We investigate whether BTC tailing can be explained by the spatial distribution of preferential flow paths and stagnation zones, which is controlled by the conductivity variance and correlation length. By combining the results from the field tests and numerical modeling, we show that the reversibility of spreading is a key mechanism that needs to be captured. We also demonstrate the dominant role of the injection

  10. Simple models for the heating curve in magnetic hyperthermia experiments

    NASA Astrophysics Data System (ADS)

    Landi, G. T.

    2013-01-01

    The use of magnetic nanoparticles for magnetic hyperthermia cancer treatment is a rapidly developing field of multidisciplinary research. From the material's standpoint, the main challenge is to optimize the heating properties of the material while maintaining the frequency of the exciting field as low as possible to avoid biological side effects. The figure of merit in this context is the specific absorption rate (SAR), which is usually measured from calorimetric experiments. Such measurements, which we refer to as heating curves, contain a substantial amount of information regarding the energy barrier distribution of the sample. This follows because the SAR itself is a function of temperature, and reflect the underlying magneto-thermal properties of the system. Unfortunately, however, this aspect of the problem is seldom explored and, commonly, only the SAR at ambient temperature is extracted from the heating curve. In this paper we introduce a simple model capable of describing the entire heating curve via a single differential equation. The SAR enters as a forcing term, thus facilitating the use of different models for it. We discuss in detail the heating in the context of Néel relaxation and show that high anisotropy samples may present an inflection point related to the reduction of the energy barrier caused by the increase in temperature. Mono-disperse and poli-disperse systems are discussed in detail and a new alternative to compute the temperature dependence of the SAR from the heating curve is presented.

  11. Eulerian hydrocode modeling of a dynamic tensile extrusion experiment (u)

    SciTech Connect

    Burkett, Michael W; Clancy, Sean P

    2009-01-01

    Eulerian hydrocode simulations utilizing the Mechanical Threshold Stress flow stress model were performed to provide insight into a dynamic extrusion experiment. The dynamic extrusion response of copper (three different grain sizes) and tantalum spheres were simulated with MESA, an explicit, 2-D Eulerian continuum mechanics hydrocode and compared with experimental data. The experimental data consisted of high-speed images of the extrusion process, recovered extruded samples, and post test metallography. The hydrocode was developed to predict large-strain and high-strain-rate loading problems. Some of the features of the features of MESA include a high-order advection algorithm, a material interface tracking scheme and a van Leer monotonic advection-limiting. The Mechanical Threshold Stress (MTS) model was utilized to evolve the flow stress as a function of strain, strain rate and temperature for copper and tantalum. Plastic strains exceeding 300% were predicted in the extrusion of copper at 400 m/s, while plastic strains exceeding 800% were predicted for Ta. Quantitative comparisons between the predicted and measured deformation topologies and extrusion rate were made. Additionally, predictions of the texture evolution (based upon the deformation rate history and the rigid body rotations experienced by the copper during the extrusion process) were compared with the orientation imaging microscopy measurements. Finally, comparisons between the calculated and measured influence of the initial texture on the dynamic extrusion response of tantalum was performed.

  12. Bio-inspired design of dental multilayers: experiments and model.

    PubMed

    Niu, Xinrui; Rahbar, Nima; Farias, Stephen; Soboyejo, Wole

    2009-12-01

    This paper combines experiments, simulations and analytical modeling that are inspired by the stress reductions associated with the functionally graded structures of the dentin-enamel-junctions (DEJs) in natural teeth. Unlike conventional crown structures in which ceramic crowns are bonded to the bottom layer with an adhesive layer, real teeth do not have a distinct "adhesive layer" between the enamel and the dentin layers. Instead, there is a graded transition from enamel to dentin within a approximately 10 to 100 microm thick regime that is called the Dentin Enamel Junction (DEJ). In this paper, a micro-scale, bio-inspired functionally graded structure is used to bond the top ceramic layer (zirconia) to a dentin-like ceramic-filled polymer substrate. The bio-inspired functionally graded material (FGM) is shown to exhibit higher critical loads over a wide range of loading rates. The measured critical loads are predicted using a rate dependent slow crack growth (RDEASCG) model. The implications of the results are then discussed for the design of bio-inspired dental multilayers. PMID:19716103

  13. Theileriosis control modelling (experiences from Southern Province, Zambia).

    PubMed

    Penne, K; D'Haese, L

    1999-09-01

    Effects of different tick-borne disease control strategies on cattle productivity are simulated based on a 30-year herd projection, calculated by a modified Markov Chain model. Input data can be grouped in technical, economic and epidemiological parameters. The output is a set of economic parameters such as benefit/cost ratio (BCR), net present value (NPV) of the profit, internal rate of return (IRR), total economic cost (TEC) as well as graphs showing animal production over time. Shadow prices are obtained for input and output in kind. Throughout the calculations a distinction is made between transactions in cash and transactions in kind. A case study was run for Southern Province, Zambia, to illustrate the model. Either vector control or treatment, or a combination of these, controls theileriosis at farm level after natural infection. Preventive immunization against the parasite is also possible. Although the calculations are based on a mixture of data obtained from literature, field experience, expert opinion and assumptions, the importance of theileriosis control is clearly indicated. Immunization gives better economic results than chemotherapy. Vector control can only be used as a last resort. PMID:10540313

  14. Modelling of the Remote Fusion Cutting Process Based on Experiments

    NASA Astrophysics Data System (ADS)

    Kristiansen, Morten; Villumsen, Sigurd; Olsen, Flemming O.

    Remote fusion cutting (RFC) is an interesting industrial process compared to traditional laser cutting. It is because traditional laser cutting is limiting travel speed and accessibility due to the required positioning of the cutting head just above the workpiece for providing a cutting gas pressure. For RFC this pressure is created by the vapor, which is formed when the laser beam evaporates the cut material. The drawback of RFC compared to traditional laser cutting is a worse cut quality, wide cut kerf and a slower travel speed. The contribution of this paper is an experimental investigation, which determined the process window for RFC in stainless steel with a single mode fiber laser. The process variables: travel speed, focus position, power and sheet thickness were investigated. Based on the results of the experiments and process knowledge the aim of this work was to determine and describe the most important driving mechanisms for understanding and modelling the RFC process. The purpose is to deepen the understanding of the mechanisms in the process and find the factors, which can improve the performance and also determine the limitations. The validation results show that the developed model of the RFC process gives a similar process window as the experimental results for the tested parameters and variation of travel speed and focus position.

  15. A new Geoengineering Model Intercomparison Project (GeoMIP) experiment designed for climate and chemistry models

    NASA Astrophysics Data System (ADS)

    Tilmes, S.; Mills, M. J.; Niemeier, U.; Schmidt, H.; Robock, A.; Kravitz, B.; Lamarque, J.-F.; Pitari, G.; English, J. M.

    2014-08-01

    A new Geoengineering Model Intercomparison Project (GeoMIP) experiment "G4 specified stratospheric aerosols" (short name: G4SSA) is proposed to investigate the impact of stratospheric aerosol geoengineering on atmospheric composition, climate, and the environment. In contrast to the earlier G4 GeoMIP experiment, which requires an emission of sulphur dioxide (SO2) into the model, a prescribed aerosol forcing file is provided to the community, to be consistently applied to future model experiments between 2020 and 2100. This stratospheric aerosol distribution, with a total burden of about 2 Tg S has been derived using the ECHAM5-HAM microphysical model, based on a continuous annual tropical emission of 8 Tg SO2 year-1. A ramp-up of geoengineering in 2020 and a ramp-down in 2070 over a period of two years are included in the distribution, while a background aerosol burden should be used for the last 3 decades of the experiment. The performance of this experiment using climate and chemistry models in a multi-model comparison framework will allow us to better understand the significance of the impact of geoengineering and the abrupt termination after 50 years on climate and composition of the atmosphere in a changing environment. The zonal and monthly mean stratospheric aerosol input dataset is available at https://www2.acd.ucar.edu/gcm/geomip-g4-specified-stratospheric-aerosol-data-set.

  16. Inverse modeling of flow tomography experiments in fractured media

    NASA Astrophysics Data System (ADS)

    Klepikova, Maria; Le Borgne, Tanguy; Bour, Olivier; de Dreuzy, Jean-Raynald

    2014-05-01

    Inverse modeling of fracture hydraulic properties and connectivity is a very challenging objective due to the strong heterogeneity of the medium at multiple scales and the scarcity of data. Cross-borehole flowmeter tests, which consist of measuring changes in vertical borehole flows when pumping a neighboring borehole, were shown to be an efficient technique to provide information on the properties of the flow zones that connect borehole pairs (Paillet, 1998, Le Borgne et al., 2007). The interpretation of such experiments may, however, be quite uncertain when multiple connections exist. We propose the flow tomography approach (i.e., sequential cross-borehole flowmeter tests) to characterize the connectivity and transmissivity of preferential permeable flow paths in fractured aquifers (Klepikova et al., 2013). An inverse model approach is developed to estimate log-transformed transmissivity values of hydraulically active fractures between the pumping and observation wells by inverting cross-borehole flow and water level data. Here a simplified discrete fracture network approach that highlights main connectivity structures is used. This conceptual model attempts to reproduce fracture network connectivity without taking fracture geometry (length, orientation, dip) into account. We demonstrate that successively exchanging the roles of pumping and observation boreholes improves the quality of available information and reduces the under-determination of the problem. The inverse method is validated for several synthetic flow scenarios. It is shown to provide a good estimation of connectivity patterns and transmissivities of main flow paths. It also allows the estimation of the transmissivity of fractures that connect the flow paths but do not cross the boreholes, although the associated uncertainty may be high for some geometries. The results of this investigation encourage the application of flow tomography to natural fractured aquifers.

  17. A New Model for Climate Science Research Experiences for Teachers

    NASA Astrophysics Data System (ADS)

    Hatheway, B.

    2012-12-01

    After two years of running a climate science teacher professional development program for secondary teachers, science educators from UCAR and UNC-Greeley have learned the benefits of providing teachers with ample time to interact with scientists, informal educators, and their teaching peers. Many programs that expose teachers to scientific research do a great job of energizing those teachers and getting them excited about how research is done. We decided to try out a twist on this model - instead of matching teachers with scientists and having them do science in the lab, we introduced the teachers to scientists who agreed share their data and answer questions as the teachers developed their own activities, curricula, and classroom materials related to the research. Prior to their summer experience, the teachers took three online courses on climate science, which increased their background knowledge and gave them an opportunity to ask higher-level questions of the scientists. By spending time with a cohort of practicing teachers, each individual had much needed time to interact with their peers, share ideas, collaborate on curriculum, and learn from each other. And because the goal of the program was to create classroom modules that could be implemented in the coming school year, the teachers were able to both learn about climate science research by interacting with scientists and visiting many different labs, and then create materials using data from the scientists. Without dedicated time for creating these classroom materials, it would have been up to the teachers to carve out time during the school year in order to find ways to apply what they learned in the research experience. We feel this approach worked better for the teachers, had a bigger impact on their students than we originally thought, and gave us a new approach to teacher professional development.

  18. MACH2 modeling of LANL plasma-flow-switch experiments

    SciTech Connect

    Wysocki, F.J.

    1994-12-31

    The plasma-flow opening-switch (PFS) is being developed at the Los Alamos National Laboratory as part of the Athena Program. The present goal is to switch 10--20 MA of current into a cylindrical-foil implosion load in 300--400 ns. Primary drivers currently in use include the Pegasus-II capacitor bank which delivers 8--10 MA to the PFS in 3--4 {mu}s and the Procyon explosively-driven flux-compression generator which delivers 15--18 MA in 2--3 {mu}s. A series of experiments using Pegasus-II and Procyon have characterized the PFS performance for a variety of experimental conditions. Issues examined with Pegasus-II include switch-mass (50-mg vs. 100-mg), switch fabrication (wire-array vs. graded-thickness-foil), current level (7 MA vs. 10 MA), presence or absence of a plasma trap, and static load vs. implosion load. Procyon has been used to characterize a PFS with a 1/r aerial-mass-density profile (as opposed to the Pegasus-II 1/r{sup 2} profile). The MACH2 two-dimensional magnetohydrodynamic code has been used to model these experiments and comparison of simulation data to the experimental data has been made. This includes direct comparison of data from an array of B-dot probes present on all tests (19--23 probes), direct comparison of x-ray yield and power for those tests with implosion loads, and qualitative comparison to framing and streak data. The agreement between simulation data and experimental data is reasonably good.

  19. Lava-substrate heat transfer: Laboratory experiments and thermodynamic modeling

    NASA Astrophysics Data System (ADS)

    Rumpf, M.; Fagents, S. A.; Hamilton, C. W.; Wright, R.; Crawford, I.

    2012-12-01

    We have performed laboratory experiments and numerical modeling to investigate the heat transfer from a lava flow into various substrate materials, focusing on the effects of the differing thermophysical properties of substrate materials. Initial motivation for this project developed from the desire to understand the loss of solar wind volatiles embedded in lunar regolith deposits that were subsequently covered by a lava flow. The Moon lacks a significant atmosphere and magnetosphere, leaving the surface regolith exposed to bombardment by solar flare and solar wind particles, and by the cosmogenic products of galactic cosmic rays. Preservation of particle-rich regolith deposits may have occurred by the emplacement of an active lava flow on top of the regolith layer, provided the embedded particles survive heating by the lava. During future expeditions to the lunar surface, ancient regolith deposits could be sampled through surface drilling to extract the extra-lunar particles, revealing a history of the solar activity and galactic events not available on the Earth. This project also has important implications for terrestrial lava flows, particularly in the prediction of lava flow hazards. Lava erupted on Earth may be emplaced on various substrates, including solid lava rock, volcanic tephra, sands, soils, etc. The composition, grain size, consolidation, moisture content, etc. of these materials will vary greatly and have different effects on the cooling of the flow. Accounting for specific properties of the substrate could be an important improvement in lava flow models We have performed laboratory experiments in collaboration with the Department of Art and Art History at the University of Hawaii at Manoa in which ~5-6 kg of basalt, collected at Kilauea Volcano, Hawaii, is melted to ~1200 °C. The lava is poured into a device constructed of calcium silicate sheeting that has been filled with a solid or particulate substrate material and embedded with thermocouples

  20. Foods - fresh vs. frozen or canned

    MedlinePlus

    ... canned vegetables. Try to buy those without added salt and don't overcook any vegetable, whether fresh, frozen, or canned. Instead of boiling them in water for longer periods of time, they should be ...

  1. A Curriculum Model for an Integrated Senior Year Clinical Experience.

    ERIC Educational Resources Information Center

    Wukasch, Ruth N.; Blue, Carolyn L.; Overbay, Jane

    2000-01-01

    A flexible clinical experience for nursing seniors integrates pediatrics, public health, and nursing leadership. Experiences in hospital units, schools, nurse-directed clinics, and home visits expose students to a wide range of settings and issues. (SK)

  2. Astrometry and geodesy with radio interferometry: experiments, models, results

    NASA Astrophysics Data System (ADS)

    Sovers, Ojars J.; Fanselow, John L.; Jacobs, Christopher S.

    1998-10-01

    Interferometry at radio frequencies between Earth-based receivers separated by intercontinental distances has made significant contributions to astrometry and geophysics during the past three decades. Analyses of such very long baseline interferometric (VLBI) experiments now permit measurements of relative positions of points on the Earth's surface and of angles between celestial objects at levels of better than one cm and one nanoradian, respectively. The relative angular positions of extragalactic radio sources inferred from this technique presently form the best realization of an inertial reference frame. This review summarizes the current status of radio interferometric measurements for astrometric and geodetic applications. It emphasizes the theoretical models that are required to extract results from the VLBI observables at present accuracy levels. An unusually broad cross section of physics contributes to the required modeling. Both special and general relativity need to be considered in properly formulating the geometric part of the propagation delay. While high-altitude atmospheric charged-particle (ionospheric) effects are easily calibrated for measurements employing two well-separated frequencies, the contribution of the neutral atmosphere at lower altitudes is more difficult to remove. In fact, mismodeling of the troposphere remains the dominant error source. Plate tectonic motions of the observing stations need to be taken into account, as well as the nonpointlike intensity distributions of many sources. Numerous small periodic and quasiperiodic tidal effects also make important contributions to space geodetic observables at the centimeter level, and some of these are just beginning to be characterized. Another area of current rapid advances is the specification of the orientation of the Earth's spin axis in inertial space: nutation and precession. Highlights of the achievements of very long baseline interferometry are presented in four areas

  3. Penaeus orientolis prawn freshness rapid determination method based on electronic nose and non-linear stochastic resonance technique

    PubMed Central

    Wei, Liu; Yuanyuan, Han; Yanping, Cai; Jiaojiao, Jin; Guohua, Hui

    2015-01-01

    In this paper, Penaeus orientolis prawn freshness rapid determination method using electronic nose (e-nose) and non-linear data processing technique is studied. E-nose responses to prawns stored at 4°C are measured. Meanwhile, physical/chemical indexes (firmness, pH, total volatile basic nitrogen (TVB-N), total viable count (TVC), and human sensory evaluation) are examined to provide freshness references for e-nose analysis. E-nose measurement data is analyzed by principal component analysis (PCA), stochastic resonance (SR), and double-layered cascaded serial stochastic resonance (DCSSR). PCA partially discriminates prawns under different storage time. SR and DCSSR signal-to-noise ratio (SNR) spectrum eigen values discriminate prawns successfully. Multi-variables regressions (MVR) are conducted between physical/chemical indexes and SR/DCSSR output SNR minimal (SNR-Min) values. Results indicate that SNR-Min values present more significant linearity relation with physical/chemical indexes. Prawn freshness forecasting model is developed via Harris fitting regression on DCSSR SNR-Min values. Validating experiments demonstrate that forecasting accuracy of this model is 94.29%. PMID:25551520

  4. Phospholipid interactions in model membrane systems. I. Experiments on monolayers.

    PubMed Central

    Mingins, J; Stigter, D; Dill, K A

    1992-01-01

    We study the lateral headgroup interactions among phosphatidylcholine (PC) molecules and among phosphatidylethanolamine (PE) molecules in monolayers and extend our previous models. In this paper, we present an extensive set of pressure-area isotherms and surface potential experiments on monolayers of phospholipids ranging from 14 to 22 carbons in length at the n-heptane/water interface, over a wide range of temperature, salt concentration, and pH on the acid side. The pressure data presented here are a considerable extension of previous data (1) to higher surface densities, comprehensively checked for monolayer loss, and include new data on PE molecules. We explore surface densities ranging from extremely low to intermediate, near to the main phase transition, in which range the surface pressures and potentials are found to be independent of the chain length. Thus, these data bear directly on the headgroup interactions. These interactions are observed to be independent of ionic strength. PC and PE molecules differ strongly in two respects: (a) the lateral repulsion among PC molecules is much stronger than for PE, and (b) the lateral repulsion among PC molecules increases strongly with temperature whereas PE interactions are almost independent of temperature. Similarly, the surface potential for PC is found to increase with temperature whereas for PE it does not. In this and the following paper we show that these data from dilute to semidilute monolayers are consistent with a theoretical model that predicts that, independent of coverage, for PC the P-N+ dipole is oriented slightly into the oil phase because of the hydrophobicity of the methyl groups, increasingly so with temperature, whereas for PE the P-N+ dipole is directed into the water phase. PMID:1617140

  5. COUNTERCURRENT FLOW LIMITATION EXPERIMENTS AND MODELING FOR IMPROVED REACTOR SAFETY

    SciTech Connect

    Vierow, Karen

    2008-09-26

    This project is investigating countercurrent flow and “flooding” phenomena in light water reactor systems to improve reactor safety of current and future reactors. To better understand the occurrence of flooding in the surge line geometry of a PWR, two experimental programs were performed. In the first, a test facility with an acrylic test section provided visual data on flooding for air-water systems in large diameter tubes. This test section also allowed for development of techniques to form an annular liquid film along the inner surface of the “surge line” and other techniques which would be difficult to verify in an opaque test section. Based on experiences in the air-water testing and the improved understanding of flooding phenomena, two series of tests were conducted in a large-diameter, stainless steel test section. Air-water test results and steam-water test results were directly compared to note the effect of condensation. Results indicate that, as for smaller diameter tubes, the flooding phenomena is predominantly driven by the hydrodynamics. Tests with the test sections inclined were attempted but the annular film was easily disrupted. A theoretical model for steam venting from inclined tubes is proposed herein and validated against air-water data. Empirical correlations were proposed for air-water and steam-water data. Methods for developing analytical models of the air-water and steam-water systems are discussed, as is the applicability of the current data to the surge line conditions. This report documents the project results from July 1, 2005 through June 30, 2008.

  6. Hazardous materials in Fresh Kills landfill

    SciTech Connect

    Hirschhorn, J.S.

    1997-12-31

    No environmental monitoring and corrective action programs can pinpoint multiple locations of hazardous materials the total amount of them in a large landfill. Yet the consequences of hazardous materials in MSW landfills are considerable, in terms of public health concerns, environmental damage, and cleanup costs. In this paper a rough estimation is made of how much hazardous material may have been disposed in Fresh Kills landfill in Staten Island, New York. The logic and methods could be used for other MSW landfills. Fresh Kills has frequently been described as the world`s largest MSW landfill. While records of hazardous waste disposal at Fresh Kills over nearly 50 years of operation certainly do not exist, no reasonable person would argue with the conclusion that large quantities of hazardous waste surely have been disposed at Fresh Kills, both legally and illegally. This study found that at least 2 million tons of hazardous wastes and substances have been disposed at Fresh Kills since 1948. Major sources are: household hazardous waste, commercial RCRA hazardous waste, incinerator ash, and commercial non-RCRA hazardous waste, governmental RCRA hazardous waste. Illegal disposal of hazardous waste surely has contributed even more. This is a sufficient amount to cause serious environmental contamination and releases, especially from such a landfill without an engineered liner system, for example. This figure is roughly 1% of the total amount of waste disposed in Fresh Kills since 1948, probably at least 200 million tons.

  7. Improved LHCD simulation model and implication for future experiments

    NASA Astrophysics Data System (ADS)

    Shiraiwa, S.; Wallace, G.; Baek, S.; Bonoli, P.; Faust, I.; Parker, R.; Labombard, B.; White, A.; Wukitch, S.

    2015-11-01

    The simulation model for LHCD using the raytracing/FokkerPlanck (GENRAY/CQL3D) code has been improved. Including realistic 2D SOL profiles resolves the discrepancy previously observed at high density (ne > 1 ×1020m-3). Impact of nonlinear interaction in front of the launcher is investigated. It is shown that the distortion of launch n| | spectrum is rather small (up to 10% of injected power). These simulation results suggest that improvement of current drive observed on Alcator C-Mod is indeed caused by realizing preferable SOL plasma profiles. Implication of these results to future experiments will be discussed. In order to minimize edge parasitic losses, realizing high single pass absorption and reducing prompt losses in front of launcher are both crucial. The advantage of LH launch from low field side (LFS) and high field side (HFS) is compared in this regards. A compact LH launcher suitable to test LH wave launch from HFS on a small scale device is designed and its plasma coupling characteristic will be presented. This work was performed on the Alcator C-Mod tokamak, a DoE Office of Science user facility, and is supported by USDoE awards DE-FC02-99ER54512 and DE-AC02-09CH11466.

  8. Experiments versus modeling of buoyant drying of porous media

    NASA Astrophysics Data System (ADS)

    Salin, Dominique; Yiotis, Andreas; Tajer, Eshan; Yortsos, Yannis

    2013-11-01

    A series of isothermal drying experiments in packed glass beads saturated with hydrocarbons are conducted. The transparent cell allow observation of the formation of liquid films, as the gaseous phase invades the pore space. We demonstrate the existence of an early Constant Rate Period that lasts as long as the films saturate the surface of the packing, and of a subsequent Falling Rate Period that begins practically after the detachment of the film tips from the external surface. During the CRP, the process is controlled by diffusion within the stagnant gaseous phase in the upper part of the cells. During the FRP, the process is controlled by diffusion within the packing, with a drying rate inversely proportional to the observed position of the observed tips in the cell. Our model incorporates effects of corner film flow, internal and external mass transfer and the effect of gravity. Analytical results were derived. We are thus able to obtain results for the drying rates, the critical saturation and the extent of the film region with respect to the various dimensionless numbers that describe the process; the Bond, Capillary numbers and the dimensionless extent of the mass boundary layer. The experimental results agree very well with the theory, provided that the latter is generalized to account for the effects of corner roundness in the film region which were neglected in our analytical approach.

  9. Storytelling Voice Conversion: Evaluation Experiment Using Gaussian Mixture Models

    NASA Astrophysics Data System (ADS)

    Přibil, Jiří; Přibilová, Anna; Ďuračková, Daniela

    2015-07-01

    In the development of the voice conversion and personification of the text-to-speech (TTS) systems, it is very necessary to have feedback information about the users' opinion on the resulting synthetic speech quality. Therefore, the main aim of the experiments described in this paper was to find out whether the classifier based on Gaussian mixture models (GMM) could be applied for evaluation of different storytelling voices created by transformation of the sentences generated by the Czech and Slovak TTS system. We suppose that it is possible to combine this GMM-based statistical evaluation with the classical one in the form of listening tests or it can replace them. The results obtained in this way were in good correlation with the results of the conventional listening test, so they confirm practical usability of the developed GMM classifier. With the help of the performed analysis, the optimal setting of the initial parameters and the structure of the input feature set for recognition of the storytelling voices was finally determined.

  10. OEDGE Modeling of Detachment Threshold Experiments on DIII-D

    NASA Astrophysics Data System (ADS)

    Elder, J. D.; Stangeby, P. C.; McLean, A. G.; Leonard, A. W.; Watkins, J. G.

    2015-11-01

    A detachment threshold experiment was performed on DIII-D in which the divertor plasma transitioned from attached to weakly detached at the strike point with minimal changes in upstream parameters. The value of Te at the outer strike point measured by Thompson scattering decreased from ~ 10eV (attached) to ~ 2 eV (weakly detached). Both the Langmuir probes and the divertor Thomson diagnostics recorded increases in the particle flux on the order of a factor of two between these divertor conditions. OEDGE is used to model both of these plasma regimes for both L-mode and H-mode discharges. The behaviour of molecular hydrogen is assessed using OEDGE and possible roles of hydrogen molecules in the detachment process are examined. Work supported by the US Department of Energy under DE-FC02-04ER54698, DE-FG02-04ER54578, DE-AC04-94AL85000, DE-AC05-00OR22725, and DE-AC52-07NA27344.

  11. Subsonic jet aeroacoustics: associating experiment, modelling and simulation

    NASA Astrophysics Data System (ADS)

    Jordan, Peter; Gervais, Yves

    2008-01-01

    An overview of jet noise research is presented wherein the principal movements in the field are traced since its beginnings. Particular attention is paid to the evolution of our understanding of what we call a “source mechanism” in free shear flows; to the theoretical, experimental and numerical studies which have nurtured this understanding; and to the currently unresolved conceptual difficulties which render analysis of experimental and numerical data so difficult. As it is clear that accelerated progress in this field of research can be made possible by a more effective synergy between the theoretical, experimental and numerical disciplines—one which draws in particular on the impressive recent progress in experimental and numerical techniques—we endeavour to elucidate the various “source” characteristics identified by these different means of study; the points on which the studies agree or disagree, and the significance of such accord or discord; and, the new analysis possibilities which can now be realised by effectively associating experiment, modelling and simulation.

  12. Hydrodynamic Modeling of the Plasma Liner Experiment (PLX)

    NASA Astrophysics Data System (ADS)

    Cassibry, Jason; Hsu, Scott; Witherspoon, Doug; Gilmore, Marc

    2009-11-01

    Implosions of plasma liners in cylindrically or spherically convergent geometries can produce high pressures and temperatures with a confinement or dwell time of the order of the rarefaction timescale of the liner. The Plasma Liner Experiment (PLX), to be built at LANL, will explore and demonstrate the feasibility of forming imploding plasma liners with the spherical convergence of hypersonic plasma jets. Modeling will be performed using SPHC and MACH2. According to preliminary 3D SPHC results, high Z plasma liners imploding on vacuum with ˜1.5MJ of initial stored energy will reach ˜100kbar, which is a main objective of the experimental program. Among the objectives of the theoretical PLX effort are to assist in the diagnostic analysis of the PLX, identify possible deleterious effects due to instabilities or asymmetries, identify departures from ideal behavior due to thermal and radiative transport, and help determine scaling laws for possible follow-on applications of ˜1 Mbar HEDP plasmas and magneto-inertial fusion. An overview of the plan to accomplish these objectives will be presented, and preliminary results will be summarized.

  13. Review of free-surface MHD experiments and modeling.

    SciTech Connect

    Molokov, S.; Reed, C. B.

    2000-06-02

    This review paper was prepared to survey the present status of analytical and experimental work in the area of free surface MHD and thus provide a well informed starting point for further work by the Advanced Limiter-diverter Plasma-facing Systems (ALPS) program. ALPS were initiated to evaluate the potential for improved performance and lifetime for plasma-facing systems. The main goal of the program is to demonstrate the advantages of advanced limiter/diverter systems over conventional systems in terms of power density capability, component lifetime, and power conversion efficiency, while providing for safe operation and minimizing impurity concerns for the plasma. Most of the work to date has been applied to free surface liquids. A multi-disciplinary team from several institutions has been organized to address the key issues associated with these systems. The main performance goals for advanced limiters and diverters are a peak heat flux of >50 MW/m{sup 2}, elimination of a lifetime limit for erosion, and the ability to extract useful heat at high power conversion efficiency ({approximately}40%). The evaluation of various options is being conducted through a combination of laboratory experiments, modeling of key processes, and conceptual design studies.

  14. Island Divertor Plate Modeling for the Compact Toroidal Hybrid Experiment

    NASA Astrophysics Data System (ADS)

    Hartwell, G. J.; Massidda, S. D.; Ennis, D. A.; Knowlton, S. F.; Maurer, D. A.; Bader, A.

    2015-11-01

    Edge magnetic island divertors can be used as a method of plasma particle and heat exhaust in long pulse stellarator experiments. Detailed power loading on these structures and its relationship to the long connection length scrape off layer physics is a new Compact Toroidal Hybrid (CTH) research thrust. CTH is a five field period, l = 2 torsatron with R0 = 0 . 75 m, ap ~ 0 . 2 m, and | B | <= 0 . 7 T. For these studies CTH is configured as a pure stellarator using a 28 GHz, 200 kW gyrotron operating at 2nd harmonic for ECRH. We report the results of EMC3-EIRENE modeling of divertor plates near magnetic island structures. The edge rotational transform is varied by adjusting the ratio of currents in the helical and toroidal field coils. A poloidal field coil adjusts the shear of the rotational transform profile, and width of the magnetic island, while the phase of the island is rotated with a set of five error coils producing an n = 1 perturbation. For the studies conducted, a magnetic configuration with a large n = 1 , m = 3 magnetic island at the edge is generated. Results from multiple potential divertor plate locations will be presented and discussed. This work is supported by U.S. Department of Energy Grant No. DE-FG02-00ER54610.

  15. Model slope infiltration experiments for shallow landslides early warning

    NASA Astrophysics Data System (ADS)

    Damiano, E.; Greco, R.; Guida, A.; Olivares, L.; Picarelli, L.

    2009-04-01

    simple empirical models [Versace et al., 2003] based on correlation between some features of rainfall records (cumulated height, duration, season etc.) and the correspondent observed landslides. Laboratory experiments on instrumented small scale slope models represent an effective way to provide data sets [Eckersley, 1990; Wang and Sassa, 2001] useful for building up more complex models of landslide triggering prediction. At the Geotechnical Laboratory of C.I.R.I.AM. an instrumented flume to investigate on the mechanics of landslides in unsaturated deposits of granular soils is available [Olivares et al. 2003; Damiano, 2004; Olivares et al., 2007]. In the flume a model slope is reconstituted by a moist-tamping technique and subjected to an artificial uniform rainfall since failure happens. The state of stress and strain of the slope is monitored during the entire test starting from the infiltration process since the early post-failure stage: the monitoring system is constituted by several mini-tensiometers placed at different locations and depths, to measure suction, mini-transducers to measure positive pore pressures, laser sensors, to measure settlements of the ground surface, and high definition video-cameras to obtain, through a software (PIV) appositely dedicated, the overall horizontal displacement field. Besides, TDR sensors, used with an innovative technique [Greco, 2006], allow to reconstruct the water content profile of soil along the entire thickness of the investigated deposit and to monitor its continuous changes during infiltration. In this paper a series of laboratory tests carried out on model slopes in granular pyroclastic soils taken in the mountainous area north-eastern of Napoli, are presented. The experimental results demonstrate the completeness of information provided by the various sensors installed. In particular, very useful information is given by the coupled measurements of soil water content by TDR and suction by tensiometers. Knowledge of

  16. Experimental determination of circumferential properties of fresh carotid artery plaques.

    PubMed

    Lawlor, Michael G; O'Donnell, Michael R; O'Connell, Barry M; Walsh, Michael T

    2011-06-01

    Carotid endarterectomy (CEA) is currently accepted as the gold standard for interventional revascularisation of diseased arteries belonging to the carotid bifurcation. Despite the proven efficacy of CEA, great interest has been generated in carotid angioplasty and stenting (CAS) as an alternative to open surgical therapy. CAS is less invasive compared with CEA, and has the potential to successfully treat lesions close to the aortic arch or distal internal carotid artery (ICA). Following promising results from two recent trials (CREST; Carotid revascularisation endarterectomy versus stenting trial, and ICSS; International carotid stenting study) it is envisaged that there will be a greater uptake in carotid stenting, especially amongst the group who do not qualify for open surgical repair, thus creating pressure to develop computational models that describe a multitude of plaque models in the carotid arteries and their reaction to the deployment of such interventional devices. Pertinent analyses will require fresh human atherosclerotic plaque material characteristics for different disease types. This study analysed atherosclerotic plaque characteristics from 18 patients tested on site, post-surgical revascularisation through endarterectomy, with 4 tissue samples being excluded from tensile testing based on large width-length ratios. According to their mechanical behaviour, atherosclerotic plaques were separated into 3 grades of stiffness. Individual and group material coefficients were then generated analytically using the Yeoh strain energy function. The ultimate tensile strength (UTS) of each sample was also recorded, showing large variation across the 14 atherosclerotic samples tested. Experimental Green strains at rupture varied from 0.299 to 0.588 and the Cauchy stress observed in the experiments was between 0.131 and 0.779 MPa. It is expected that this data may be used in future design optimisation of next generation interventional medical devices for the

  17. The long-term fate of fresh and frozen orthotopic bone allografts in genetically defined rats.

    PubMed

    Bos, G D; Goldberg, V M; Gordon, N H; Dollinger, B M; Zika, J M; Powell, A E; Heiple, K G

    1985-01-01

    Fresh and frozen orthotopic iliac crest bone grafts in rats were studied histologically for determination of the long-term effects of histocompatibility matching and the freezing process on orthotopic bone graft incorporation. Grafts exchanged between groups of inbred rats, syngeneic or differing with respect to major or minor histocompatibility loci, were studied histologically at 20, 30, 40, 50, and 150 days after bone transplantation. A numerical histologic scoring system was developed and used by three observers for evaluation of coded hematoxylin and eosin sections. All frozen graft groups had the same fate regardless of histocompatibility relations between donors and recipients, and all grafts were inferior to fresh syngeneic grafts. Both fresh allograft groups received similar scores and initially at 20 and 30 days had scores similar to those of the fresh syngeneic groups. In the later intervals, however, the fresh allografts were inferior to the fresh syngeneic grafts and similar to the frozen groups. This is consistent with an older model describing two distinct phases of osteogenesis. In the long term, frozen syngeneic and fresh and frozen allografts across major and minor histocompatibility barriers were comparable, but all were significantly inferior to fresh syngeneic bone grafts. PMID:3893828

  18. Fresh Water Content Variability in the Arctic Ocean

    NASA Technical Reports Server (NTRS)

    Hakkinen, Sirpa; Proshutinsky, Andrey

    2003-01-01

    Arctic Ocean model simulations have revealed that the Arctic Ocean has a basin wide oscillation with cyclonic and anticyclonic circulation anomalies (Arctic Ocean Oscillation; AOO) which has a prominent decadal variability. This study explores how the simulated AOO affects the Arctic Ocean stratification and its relationship to the sea ice cover variations. The simulation uses the Princeton Ocean Model coupled to sea ice. The surface forcing is based on NCEP-NCAR Reanalysis and its climatology, of which the latter is used to force the model spin-up phase. Our focus is to investigate the competition between ocean dynamics and ice formation/melt on the Arctic basin-wide fresh water balance. We find that changes in the Atlantic water inflow can explain almost all of the simulated fresh water anomalies in the main Arctic basin. The Atlantic water inflow anomalies are an essential part of AOO, which is the wind driven barotropic response to the Arctic Oscillation (AO). The baroclinic response to AO, such as Ekman pumping in the Beaufort Gyre, and ice meldfreeze anomalies in response to AO are less significant considering the whole Arctic fresh water balance.

  19. Model slope infiltration experiments for shallow landslides early warning

    NASA Astrophysics Data System (ADS)

    Damiano, E.; Greco, R.; Guida, A.; Olivares, L.; Picarelli, L.

    2009-04-01

    simple empirical models [Versace et al., 2003] based on correlation between some features of rainfall records (cumulated height, duration, season etc.) and the correspondent observed landslides. Laboratory experiments on instrumented small scale slope models represent an effective way to provide data sets [Eckersley, 1990; Wang and Sassa, 2001] useful for building up more complex models of landslide triggering prediction. At the Geotechnical Laboratory of C.I.R.I.AM. an instrumented flume to investigate on the mechanics of landslides in unsaturated deposits of granular soils is available [Olivares et al. 2003; Damiano, 2004; Olivares et al., 2007]. In the flume a model slope is reconstituted by a moist-tamping technique and subjected to an artificial uniform rainfall since failure happens. The state of stress and strain of the slope is monitored during the entire test starting from the infiltration process since the early post-failure stage: the monitoring system is constituted by several mini-tensiometers placed at different locations and depths, to measure suction, mini-transducers to measure positive pore pressures, laser sensors, to measure settlements of the ground surface, and high definition video-cameras to obtain, through a software (PIV) appositely dedicated, the overall horizontal displacement field. Besides, TDR sensors, used with an innovative technique [Greco, 2006], allow to reconstruct the water content profile of soil along the entire thickness of the investigated deposit and to monitor its continuous changes during infiltration. In this paper a series of laboratory tests carried out on model slopes in granular pyroclastic soils taken in the mountainous area north-eastern of Napoli, are presented. The experimental results demonstrate the completeness of information provided by the various sensors installed. In particular, very useful information is given by the coupled measurements of soil water content by TDR and suction by tensiometers. Knowledge of

  20. Modeling of coherent ultrafast magneto-optical experiments: Light-induced molecular mean-field model

    SciTech Connect

    Hinschberger, Y.; Hervieux, P.-A.

    2015-12-28

    We present calculations which aim to describe coherent ultrafast magneto-optical effects observed in time-resolved pump-probe experiments. Our approach is based on a nonlinear semi-classical Drude-Voigt model and is used to interpret experiments performed on nickel ferromagnetic thin film. Within this framework, a phenomenological light-induced coherent molecular mean-field depending on the polarizations of the pump and probe pulses is proposed whose microscopic origin is related to a spin-orbit coupling involving the electron spins of the material sample and the electric field of the laser pulses. Theoretical predictions are compared to available experimental data. The model successfully reproduces the observed experimental trends and gives meaningful insight into the understanding of magneto-optical rotation behavior in the ultrafast regime. Theoretical predictions for further experimental studies are also proposed.

  1. Establishing the Global Fresh Water Sensor Web

    NASA Technical Reports Server (NTRS)

    Hildebrand, Peter H.

    2005-01-01

    This paper presents an approach to measuring the major components of the water cycle from space using the concept of a sensor-web of satellites that are linked to a data assimilation system. This topic is of increasing importance, due to the need for fresh water to support the growing human population, coupled with climate variability and change. The net effect is that water is an increasingly valuable commodity. The distribution of fresh water is highly uneven over the Earth, with both strong latitudinal distributions due to the atmospheric general circulation, and even larger variability due to landforms and the interaction of land with global weather systems. The annual global fresh water budget is largely a balance between evaporation, atmospheric transport, precipitation and runoff. Although the available volume of fresh water on land is small, the short residence time of water in these fresh water reservoirs causes the flux of fresh water - through evaporation, atmospheric transport, precipitation and runoff - to be large. With a total atmospheric water store of approx. 13 x 10(exp 12)cu m, and an annual flux of approx. 460 x 10(exp 12)cu m/y, the mean atmospheric residence time of water is approx. 10 days. River residence times are similar, biological are approx. 1 week, soil moisture is approx. 2 months, and lakes and aquifers are highly variable, extending from weeks to years. The hypothesized potential for redistribution and acceleration of the global hydrological cycle is therefore of concern. This hypothesized speed-up - thought to be associated with global warming - adds to the pressure placed upon water resources by the burgeoning human population, the variability of weather and climate, and concerns about anthropogenic impacts on global fresh water availability.

  2. Mesoscale Modeling During Mixed-Phase Arctic Cloud Experiment

    SciTech Connect

    Avramov, A.; Harringston, J.Y.; Verlinde, J.

    2005-03-18

    Mixed-phase arctic stratus clouds are the predominant cloud type in the Arctic (Curry et al. 2000) and through various feedback mechanisms exert a strong influence on the Arctic climate. Perhaps one of the most intriguing of their features is that they tend to have liquid tops that precipitate ice. Despite the fact that this situation is colloidally unstable, these cloud systems are quite long lived - from a few days to over a couple of weeks. It has been hypothesized that mixed-phase clouds are maintained through a balance between liquid water condensation resulting from the cloud-top radiative cooling and ice removal by precipitation (Pinto 1998; Harrington et al. 1999). In their modeling study Harrington et al. (1999) found that the maintenance of this balance depends strongly on the ambient concentration of ice forming nucleus (IFN). In a follow-up study, Jiang et al. (2002), using only 30% of IFN concentration predicted by Meyers et al. (1992) IFN parameterization were able to obtain results similar to the observations reported by Pinto (1998). The IFN concentration measurements collected during the Mixed-Phase Arctic Cloud Experiment (M-PACE), conducted in October 2004 over the North Slope of Alaska and the Beaufort Sea (Verlinde et al. 2005), also showed much lower values then those predicted (Prenne, pers. comm.) by currently accepted ice nucleation parameterizations (e.g. Meyers et al. 1992). The goal of this study is to use the extensive IFN data taken during M-PACE to examine what effects low IFN concentrations have on mesoscale cloud structure and coastal dynamics.

  3. Earthquake nucleation mechanisms and periodic loading: Models, Experiments, and Observations

    NASA Astrophysics Data System (ADS)

    Dahmen, K.; Brinkman, B.; Tsekenis, G.; Ben-Zion, Y.; Uhl, J.

    2010-12-01

    The project has two main goals: (a) Improve the understanding of how earthquakes are nucleated ¬ with specific focus on seismic response to periodic stresses (such as tidal or seasonal variations) (b) Use the results of (a) to infer on the possible existence of precursory activity before large earthquakes. A number of mechanisms have been proposed for the nucleation of earthquakes, including frictional nucleation (Dieterich 1987) and fracture (Lockner 1999, Beeler 2003). We study the relation between the observed rates of triggered seismicity, the period and amplitude of cyclic loadings and whether the observed seismic activity in response to periodic stresses can be used to identify the correct nucleation mechanism (or combination of mechanisms). A generalized version of the Ben-Zion and Rice model for disordered fault zones and results from related recent studies on dislocation dynamics and magnetization avalanches in slowly magnetized materials are used in the analysis (Ben-Zion et al. 2010; Dahmen et al. 2009). The analysis makes predictions for the statistics of macroscopic failure events of sheared materials in the presence of added cyclic loading, as a function of the period, amplitude, and noise in the system. The employed tools include analytical methods from statistical physics, the theory of phase transitions, and numerical simulations. The results will be compared to laboratory experiments and observations. References: Beeler, N.M., D.A. Lockner (2003). Why earthquakes correlate weakly with the solid Earth tides: effects of periodic stress on the rate and probability of earthquake occurrence. J. Geophys. Res.-Solid Earth 108, 2391-2407. Ben-Zion, Y. (2008). Collective Behavior of Earthquakes and Faults: Continuum-Discrete Transitions, Evolutionary Changes and Corresponding Dynamic Regimes, Rev. Geophysics, 46, RG4006, doi:10.1029/2008RG000260. Ben-Zion, Y., Dahmen, K. A. and J. T. Uhl (2010). A unifying phase diagram for the dynamics of sheared solids

  4. Exposures from indoor powder releases: models and experiments

    SciTech Connect

    Cooper, D.W.; Horowitz, M.

    1986-04-01

    Two models of the dispersion of a solid contaminant in a room were compared. The first model was the perfect mixing model. widely used in room air modeling to predict concentration, thus exposure (the integral of concentration over time). The second model was the turbulent puff diffusion model, sometimes used in atmospheric dispersion modeling. The models predicted different consequences from a solid contaminant release in a room, such as from a bulk-loading operation or a spill. The predicted exposures from a release were evaluated for both models. The models also were compared against data from an illustrative set of experimental measurements with the use of powder spill as a source. In the room, the exposures decreased almost inversely with distance, behavior more in accord with the turbulent puff model than with the perfect mixing model.

  5. Response Surface Model Building Using Orthogonal Arrays for Computer Experiments

    NASA Technical Reports Server (NTRS)

    Unal, Resit; Braun, Robert D.; Moore, Arlene A.; Lepsch, Roger A.

    1997-01-01

    This study investigates response surface methods for computer experiments and discusses some of the approaches available. Orthogonal arrays constructed for computer experiments are studied and an example application to a technology selection and optimization study for a reusable launch vehicle is presented.

  6. Antimicrobial properties of natural substances in irradiated fresh poultry

    NASA Astrophysics Data System (ADS)

    Mahrour, A.; Lacroix, M.; Nketsa-Tabiri, J.; Calderon, N.; Gagnon, M.

    1998-06-01

    This study was undertaken to determine if a combined treatment (marinating in natural plant extracts or vacuum) with irradiation could have a synergetic effect, in order to reduce the dose required for complete elimination of Salmonella on fresh poultry. The effect of these combined treatments on the shelf-life extension was also evaluated. The fresh chicken legs were irradiated at 0, 3 and 5 kGy. The poultry underwent microbial analysis(mesophilic and Salmonella detection). For each treatment, the total microbial count decreased with increase of irradiation dose. The marinating treatment have a synergistic effect with irradiation treatment to reduce the total microbial count and controlling the proliferation during storage at 4°C. Irradiation of fresh chicken pieces with a dose of 3 kGy appears to be able to extend the microbial shelf-life by a factor of 2. When the chicken is marinating and irradiated at 3 kGy or when irradiated at 5 kGy without marinating, the microbial shelf-life is extended by a factor of 7 to 8. No Salmonella was found during all the experiment in the chicken in air and marinated. However, a presence of Salmonella was found in samples irradiated at 5 kGy under vacuum, in unirradiated samples and samples irradiated at 3kGy in air and under vacuum.

  7. Quality and shelf-life prediction for retail fresh hake (Merluccius merluccius).

    PubMed

    García, Míriam R; Vilas, Carlos; Herrera, Juan R; Bernárdez, Marta; Balsa-Canto, Eva; Alonso, Antonio A

    2015-09-01

    Fish quality has a direct impact on market price and its accurate assessment and prediction are of main importance to set prices, increase competitiveness, resolve conflicts of interest and prevent food wastage due to conservative product shelf-life estimations. In this work we present a general methodology to derive predictive models of fish freshness under different storage conditions. The approach makes use of the theory of optimal experimental design, to maximize data information and in this way reduce the number of experiments. The resulting growth model for specific spoilage microorganisms in hake (Merluccius merluccius) is sufficiently informative to estimate quality sensory indexes under time-varying temperature profiles. In addition it incorporates quantitative information of the uncertainty induced by fish variability. The model has been employed to test the effect of factors such as fishing gear or evisceration, on fish spoilage and therefore fish quality. Results show no significant differences in terms of microbial growth between hake fished by long-line or bottom-set nets, within the implicit uncertainty of the model. Similar conclusions can be drawn for gutted and un-gutted hake along the experiment horizon. In addition, whenever there is the possibility to carry out the necessary experiments, this approach is sufficiently general to be used in other fish species and under different stress variables. PMID:26058006

  8. Fresh fruit: microstructure, texture, and quality

    NASA Astrophysics Data System (ADS)

    Wood, Delilah F.; Imam, Syed H.; Orts, William J.; Glenn, Gregory M.

    2009-05-01

    Fresh-cut produce has a huge following in today's supermarkets. The trend follows the need to decrease preparation time as well as the desire to follow the current health guidelines for consumption of more whole "heart-healthy" foods. Additionally, consumers are able to enjoy a variety of fresh produce regardless of the local season because produce is now shipped world-wide. However, most fruits decompose rapidly once their natural packaging has been disrupted by cutting. In addition, some intact fruits have limited shelf-life which, in turn, limits shipping and storage. Therefore, a basic understanding of how produce microstructure relates to texture and how microstructure changes as quality deteriorates is needed to ensure the best quality in the both the fresh-cut and the fresh produce markets. Similarities between different types of produce include desiccation intolerance which produces wrinkling of the outer layers, cracking of the cuticle and increased susceptibility to pathogen invasion. Specific examples of fresh produce and their corresponding ripening and storage issues, and degradation are shown in scanning electron micrographs.

  9. (A Model for a Rural School Field Experience--The "Condon Experience".)

    ERIC Educational Resources Information Center

    Hull, Ray; And Others

    1979-01-01

    Condon, a community of approximately 950 people in central Oregon, opened its high school to 15 undergraduate secondary education students from the University of Oregon and provided them with perhaps the richest experience of their preprofessional training. (Author/BR)

  10. Historical and idealized climate model experiments: an intercomparison of Earth system models of intermediate complexity

    NASA Astrophysics Data System (ADS)

    Eby, M.; Weaver, A. J.; Alexander, K.; Zickfeld, K.; Abe-Ouchi, A.; Cimatoribus, A. A.; Crespin, E.; Drijfhout, S. S.; Edwards, N. R.; Eliseev, A. V.; Feulner, G.; Fichefet, T.; Forest, C. E.; Goosse, H.; Holden, P. B.; Joos, F.; Kawamiya, M.; Kicklighter, D.; Kienert, H.; Matsumoto, K.; Mokhov, I. I.; Monier, E.; Olsen, S. M.; Pedersen, J. O. P.; Perrette, M.; Philippon-Berthier, G.; Ridgwell, A.; Schlosser, A.; Schneider von Deimling, T.; Shaffer, G.; Smith, R. S.; Spahni, R.; Sokolov, A. P.; Steinacher, M.; Tachiiri, K.; Tokos, K.; Yoshimori, M.; Zeng, N.; Zhao, F.

    2013-05-01

    Both historical and idealized climate model experiments are performed with a variety of Earth system models of intermediate complexity (EMICs) as part of a community contribution to the Intergovernmental Panel on Climate Change Fifth Assessment Report. Historical simulations start at 850 CE and continue through to 2005. The standard simulations include changes in forcing from solar luminosity, Earth's orbital configuration, CO2, additional greenhouse gases, land use, and sulphate and volcanic aerosols. In spite of very different modelled pre-industrial global surface air temperatures, overall 20th century trends in surface air temperature and carbon uptake are reasonably well simulated when compared to observed trends. Land carbon fluxes show much more variation between models than ocean carbon fluxes, and recent land fluxes appear to be slightly underestimated. It is possible that recent modelled climate trends or climate-carbon feedbacks are overestimated resulting in too much land carbon loss or that carbon uptake due to CO2 and/or nitrogen fertilization is underestimated. Several one thousand year long, idealized, 2 × and 4 × CO2 experiments are used to quantify standard model characteristics, including transient and equilibrium climate sensitivities, and climate-carbon feedbacks. The values from EMICs generally fall within the range given by general circulation models. Seven additional historical simulations, each including a single specified forcing, are used to assess the contributions of different climate forcings to the overall climate and carbon cycle response. The response of surface air temperature is the linear sum of the individual forcings, while the carbon cycle response shows a non-linear interaction between land-use change and CO2 forcings for some models. Finally, the preindustrial portions of the last millennium simulations are used to assess historical model carbon-climate feedbacks. Given the specified forcing, there is a tendency for the

  11. Model-experiment interaction to improve representation of phosphorus limitation in land models

    NASA Astrophysics Data System (ADS)

    Norby, R. J.; Yang, X.; Cabugao, K. G. M.; Childs, J.; Gu, L.; Haworth, I.; Mayes, M. A.; Porter, W. S.; Walker, A. P.; Weston, D. J.; Wright, S. J.

    2015-12-01

    Carbon-nutrient interactions play important roles in regulating terrestrial carbon cycle responses to atmospheric and climatic change. None of the CMIP5 models has included routines to represent the phosphorus (P) cycle, although P is commonly considered to be the most limiting nutrient in highly productive, lowland tropical forests. Model simulations with the Community Land Model (CLM-CNP) show that inclusion of P coupling leads to a smaller CO2 fertilization effect and warming-induced CO2 release from tropical ecosystems, but there are important uncertainties in the P model, and improvements are limited by a dearth of data. Sensitivity analysis identifies the relative importance of P cycle parameters in determining P availability and P limitation, and thereby helps to define the critical measurements to make in field campaigns and manipulative experiments. To improve estimates of P supply, parameters that describe maximum amount of labile P in soil and sorption-desorption processes are necessary for modeling the amount of P available for plant uptake. Biochemical mineralization is poorly constrained in the model and will be improved through field observations that link root traits to mycorrhizal activity, phosphatase activity, and root depth distribution. Model representation of P demand by vegetation, which currently is set by fixed stoichiometry and allometric constants, requires a different set of data. Accurate carbon cycle modeling requires accurate parameterization of the photosynthetic machinery: Vc,max and Jmax. Relationships between the photosynthesis parameters and foliar nutrient (N and P) content are being developed, and by including analysis of covariation with other plant traits (e.g., specific leaf area, wood density), we can provide a basis for more dynamic, trait-enabled modeling. With this strong guidance from model sensitivity and uncertainty analysis, field studies are underway in Puerto Rico and Panama to collect model-relevant data on P

  12. Fresh groundwater resources in a large sand replenishment

    NASA Astrophysics Data System (ADS)

    Huizer, Sebastian; Oude Essink, Gualbert H. P.; Bierkens, Marc F. P.

    2016-08-01

    The anticipation of sea-level rise and increases in extreme weather conditions has led to the initiation of an innovative coastal management project called the Sand Engine. In this pilot project a large volume of sand (21.5 million m3) - also called sand replenishment or nourishment - was placed on the Dutch coast. The intention is that the sand is redistributed by wind, current, and tide, reinforcing local coastal defence structures and leading to a unique, dynamic environment. In this study we investigated the potential effect of the long-term morphological evolution of the large sand replenishment and climate change on fresh groundwater resources. The potential effects on the local groundwater system were quantified with a calibrated three-dimensional (3-D) groundwater model, in which both variable-density groundwater flow and salt transport were simulated. Model simulations showed that the long-term morphological evolution of the Sand Engine results in a substantial growth of fresh groundwater resources, in all adopted climate change scenarios. Thus, the application of a local sand replenishment could provide coastal areas the opportunity to combine coastal protection with an increase of the local fresh groundwater availability.

  13. Prediction of tomato freshness using infrared thermal imaging and transient step heating

    NASA Astrophysics Data System (ADS)

    Xie, Jing; Hsieh, Sheng-Jen; Tan, Zuojun; Wang, Hongjin; Zhang, Jian

    2016-05-01

    Tomatoes are the world's 8th most valuable agricultural product, valued at $58 billion dollars annually. Nondestructive testing and inspection of tomatoes is challenging and multi-faceted. Optical imaging is used for quality grading and ripeness. Spectral and hyperspectral imaging are used to detect surface detects and cuticle cracks. Infrared thermography has been used to distinguish between different stages of maturity. However, determining the freshness of tomatoes is still an open problem. For this research, infrared thermography was used for freshness prediction. Infrared images were captured at a rate of 1 frame per second during heating (0 to 40 seconds) and cooling (0 to 160 seconds). The absolute temperatures of the acquired images were plotted. Regions with higher temperature differences between fresh and less fresh (rotten within three days) tomatoes of approximately uniform size and shape were used as the input nodes in a three-layer artificial neural network (ANN) model. Two-thirds of the data were used for training and one-third was used for testing. Results suggest that by using infrared imaging data as input to an ANN model, tomato freshness can be predicted with 90% accuracy. T-tests and F-tests were conducted based on absolute temperature over time. The results suggest that there is a mean temperature difference between fresh and less fresh tomatoes (α = 0.05). However, there is no statistical difference in terms of temperature variation, which suggests a water concentration difference.

  14. Synchronization Experiments With A Global Coupled Model of Intermediate Complexity

    NASA Astrophysics Data System (ADS)

    Selten, Frank; Hiemstra, Paul; Shen, Mao-Lin

    2013-04-01

    In the super modeling approach an ensemble of imperfect models are connected through nudging terms that nudge the solution of each model to the solution of all other models in the ensemble. The goal is to obtain a synchronized state through a proper choice of connection strengths that closely tracks the trajectory of the true system. For the super modeling approach to be successful, the connections should be dense and strong enough for synchronization to occur. In this study we analyze the behavior of an ensemble of connected global atmosphere-ocean models of intermediate complexity. All atmosphere models are connected to the same ocean model through the surface fluxes of heat, water and momentum, the ocean is integrated using weighted averaged surface fluxes. In particular we analyze the degree of synchronization between the atmosphere models and the characteristics of the ensemble mean solution. The results are interpreted using a low order atmosphere-ocean toy model.

  15. Development and validation of an evaporation duct model. Part I: Model establishment and sensitivity experiments

    NASA Astrophysics Data System (ADS)

    Ding, Juli; Fei, Jianfang; Huang, Xiaogang; Cheng, Xiaoping; Hu, Xiaohua; Ji, Liang

    2015-06-01

    Based on the Coupled Ocean-Atmospheric Response Experiment (COARE) bulk algorithm and the Naval Postgraduate School (NPS) model, a universal evaporation duct (UED) model that can flexibly accommodate the latest improvements in component (such as stability function, velocity roughness, and scalar roughness) schemes for different stratification and wind conditions, is proposed in this paper. With the UED model, the sensitivity of the model-derived evaporation duct height (EDH) to stability function ( ψ), ocean wave effect under moderate to high wind speeds, and scalar roughness length parameterization, is investigated, and relative contributions of these factors are compared. The results show that the stability function is a key factor influencing the simulated EDH values. Under unstable conditions, the EDH values from stability functions of Fairall et al. (1996) and Hu and Zhang (1992) are generally higher than those from others; while under stable conditions, unreasonably high EDHs can be avoided by use of the stability functions of Hu and Zhang (1992) and Grachev et al. (2007). Under moderate to high wind speeds, the increase in velocity roughness length z 0 due to consideration of the true ocean wave effect acts to reduce modeled EDH values; this trend is more pronounced under stable conditions. Although the scalar roughness length parameterization has a minor effect on the model-derived EDH, a positive correlation is found between the scalar roughness length z 0 q and the model-derived EDH.

  16. Caesium sorption by hydrated cement as a function of degradation state: Experiments and modelling

    SciTech Connect

    Ochs, M. . E-mail: michael.ochs@bmgeng.ch; Pointeau, I.

    2006-07-01

    To provide reliable K {sub d} data for Cs required for the performance assessment of cement-based radioactive waste repositories, two complementary approaches were followed. First, Cs sorption was determined on a range of hydrated cement paste (HCP) and mortar samples of CEM I and CEM V for different degradation states and solution compositions, as well as on some single mineral phases. Second, a surface complexation-diffuse layer model previously developed by Pointeau et al. [Pointeau, I., Marmier, N., Fromage, F., Fedoroff, M., Giffaut, E., 2001. Cs and Pb uptake by CSH phases of hydrated cement. Material Research Society Symposium Proceedings, 663, 105-113] for Cs sorption on synthetic CSH phases was simplified to facilitate its application to whole HCP and mortars or concrete, following re-assessment of the model parameters. All measurements were compared with model predictions. The sorption data obtained on the different solid phases as a function of conditions corroborate that CSH minerals are the main sorbing phase for Cs in HCP. The data also clearly show the important influence of pH and the dissolved concentration of Na, K and Ca on K {sub d}. It is further suggested that a decrease of pH is concomitant with a decrease of the Ca/Si ratio and a corresponding increase in surface sites with high affinity for Cs and, thus, K {sub d}. Elevated concentrations of cations able to compete with Cs for these sites lead to a decrease of K {sub d}, on the other hand. The simplified model was applied to the sorption measurements performed within this study as well as to a variety of literature data, mainly K {sub d} values for a variety of fresh HCP and mortar or concrete samples based on different samples of Ordinary Portland Cement as well as blended cements. The results show that the model can be applied reasonably well to a very large variety of conditions in terms of solid and solution compositions that cover a range of K {sub d} values from 10{sup -4} to ca. 3

  17. Caesium sorption by hydrated cement as a function of degradation state: experiments and modelling.

    PubMed

    Ochs, M; Pointeau, I; Giffaut, E

    2006-01-01

    To provide reliable K(d) data for Cs required for the performance assessment of cement-based radioactive waste repositories, two complementary approaches were followed. First, Cs sorption was determined on a range of hydrated cement paste (HCP) and mortar samples of CEM I and CEM V for different degradation states and solution compositions, as well as on some single mineral phases. Second, a surface complexation-diffuse layer model previously developed by Pointeau et al. [Pointeau, I., Marmier, N., Fromage, F., Fedoroff, M., Giffaut, E., 2001. Cs and Pb uptake by CSH phases of hydrated cement. Material Research Society Symposium Proceedings, 663, 105-113] for Cs sorption on synthetic CSH phases was simplified to facilitate its application to whole HCP and mortars or concrete, following re-assessment of the model parameters. All measurements were compared with model predictions. The sorption data obtained on the different solid phases as a function of conditions corroborate that CSH minerals are the main sorbing phase for Cs in HCP. The data also clearly show the important influence of pH and the dissolved concentration of Na, K and Ca on K(d). It is further suggested that a decrease of pH is concomitant with a decrease of the Ca/Si ratio and a corresponding increase in surface sites with high affinity for Cs and, thus, K(d). Elevated concentrations of cations able to compete with Cs for these sites lead to a decrease of K(d), on the other hand. The simplified model was applied to the sorption measurements performed within this study as well as to a variety of literature data, mainly K(d) values for a variety of fresh HCP and mortar or concrete samples based on different samples of Ordinary Portland Cement as well as blended cements. The results show that the model can be applied reasonably well to a very large variety of conditions in terms of solid and solution compositions that cover a range of K(d) values from 10(-4) to ca. 3.2m(3)/kg. The large scatter

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

    NASA Astrophysics Data System (ADS)

    Blikstein, Paulo; Fuhrmann, Tamar; Salehi, Shima

    2016-08-01

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

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

    NASA Astrophysics Data System (ADS)

    Blikstein, Paulo; Fuhrmann, Tamar; Salehi, Shima

    2016-05-01

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

  20. Decontamination of fresh and fresh-cut fruits and vegetables with cold plasma technology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Contamination of fresh and fresh-cut fruits and vegetables by foodborne pathogens has prompted research into novel interventions. Cold plasma is a nonthermal food processing technology which uses energetic, reactive gases to inactivate contaminating microbes. This flexible sanitizing method uses ele...

  1. What is a fresh scent in perfumery? Perceptual freshness is correlated with substantivity.

    PubMed

    Zarzo, Manuel

    2013-01-01

    Perfumes are manufactured by mixing odorous materials with different volatilities. The parameter that measures the lasting property of a material when applied on the skin is called substantivity or tenacity. It is well known by perfumers that citrus and green notes are perceived as fresh and they tend to evaporate quickly, while odors most dissimilar to 'fresh' (e.g., oriental, powdery, erogenic and animalic scents) are tenacious. However, studies aimed at quantifying the relationship between fresh odor quality and substantivity have not received much attention. In this work, perceptual olfactory ratings on a fresh scale, estimated in a previous study, were compared with substantivity parameters and antierogenic ratings from the literature. It was found that the correlation between fresh odor character and odorant substantivity is quite strong (r = -0.85). 'Fresh' is sometimes interpreted in perfumery as 'cool' and the opposite of 'warm'. This association suggests that odor freshness might be somehow related to temperature. Assuming that odor perception space was shaped throughout evolution in temperate climates, results reported here are consistent with the hypothesis that 'fresh' evokes scents typically encountered in the cool season, while 'warm' would be evoked by odors found in nature during summer. This hypothesis is rather simplistic but it may provide a new insight to better understand the perceptual space of scents. PMID:23275083

  2. Consumer's Fresh Produce Food Safety Practices: Outcomes of a Fresh Produce Safety Education Program

    ERIC Educational Resources Information Center

    Scott, Amanda R.; Pope, Paul E.; Thompson, Britta M.

    2009-01-01

    The Centers for Disease Control and Prevention estimate that there are 76 million cases of foodborne disease annually. Foodborne disease is usually associated with beef, poultry, and seafood. However, there is an increasing number of foodborne disease cases related to fresh produce. Consumers may not associate fresh produce with foodborne disease…

  3. Irradiation of fresh and fresh-cut fruits and vegetables: quality and shelf-life

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of ionizing radiation on each quality parameters (appearance, texture, flavor/taste and nutritional values) of fresh produce are reviewed with a focus on recent developments on fresh-cut fruits and vegetables. Changes in respiration rate, ethylene production and enzymatic activities are ...

  4. A fresh fruit and vegetable program improves high school students' consumption of fresh produce

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Low fruit and vegetable intake may be associated with overweight. The United States Department of Agriculture implemented the Fresh Fruit and Vegetable Program in 2006-2007. One Houston-area high school was selected and received funding to provide baskets of fresh fruits and vegetables daily for eac...

  5. Critical Issues in Maintaining Fresh and Fresh-cut Produce Safety

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An increasing number of food-borne illness outbreaks have been associated with the consumption of fresh and fresh-cut produce contaminated with human pathogens. Produce grows in the natural environment and undergoes much handling on its journey from farm to table, making it vulnerable to human path...

  6. Inheritance of fresh-cut fruit quality attributes in Capsicum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fresh-cut fruit and vegetable industry has expanded rapidly during the past decade, due to freshness, convenience and the high nutrition that fresh-cut produce offers to consumers. The current report evaluates the inheritance of postharvest attributes that contribute to pepper fresh-cut product...

  7. 9 CFR 319.141 - Fresh pork sausage.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Fresh pork sausage. 319.141 Section... Sausage § 319.141 Fresh pork sausage. “Fresh Pork Sausage” is sausage prepared with fresh pork or frozen pork or both, but not including pork byproducts, and may contain Mechanically Separated (Species)...

  8. Modified atmosphere packaging for fresh-cut fruits and vegetables

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The latest development in and different aspects of modified atmosphere packaging for fresh-cut fruits and vegetables are reviewed in the book. This book provides all readers, including fresh-cut academic researchers, fresh-cut R&D personnel, and fresh-cut processing engineers, with unique, essential...

  9. A portable device for rapid nondestructive detection of fresh meat quality

    NASA Astrophysics Data System (ADS)

    Lin, Wan; Peng, Yankun

    2014-05-01

    Quality attributes of fresh meat influence nutritional value and consumers' purchasing power. In order to meet the demand of inspection department for portable device, a rapid and nondestructive detection device for fresh meat quality based on ARM (Advanced RISC Machines) processor and VIS/NIR technology was designed. Working principal, hardware composition, software system and functional test were introduced. Hardware system consisted of ARM processing unit, light source unit, detection probe unit, spectral data acquisition unit, LCD (Liquid Crystal Display) touch screen display unit, power unit and the cooling unit. Linux operating system and quality parameters acquisition processing application were designed. This system has realized collecting spectral signal, storing, displaying and processing as integration with the weight of 3.5 kg. 40 pieces of beef were used in experiment to validate the stability and reliability. The results indicated that prediction model developed using PLSR method using SNV as pre-processing method had good performance, with the correlation coefficient of 0.90 and root mean square error of 1.56 for validation set for L*, 0.95 and 1.74 for a*,0.94 and 0.59 for b*, 0.88 and 0.13 for pH, 0.79 and 12.46 for tenderness, 0.89 and 0.91 for water content, respectively. The experimental result shows that this device can be a useful tool for detecting quality of meat.

  10. HCCI experiments with toluene reference fuels modeled by a semidetailed chemical kinetic model

    SciTech Connect

    Andrae, J.C.G.; Brinck, T.; Kalghatgi, G.T.

    2008-12-15

    A semidetailed mechanism (137 species and 633 reactions) and new experiments in a homogeneous charge compression ignition (HCCI) engine on the autoignition of toluene reference fuels are presented. Skeletal mechanisms for isooctane and n-heptane were added to a detailed toluene submechanism. The model shows generally good agreement with ignition delay times measured in a shock tube and a rapid compression machine and is sensitive to changes in temperature, pressure, and mixture strength. The addition of reactions involving the formation and destruction of benzylperoxide radical was crucial to modeling toluene shock tube data. Laminar burning velocities for benzene and toluene were well predicted by the model after some revision of the high-temperature chemistry. Moreover, laminar burning velocities of a real gasoline at 353 and 500 K could be predicted by the model using a toluene reference fuel as a surrogate. The model also captures the experimentally observed differences in combustion phasing of toluene/n-heptane mixtures, compared to a primary reference fuel of the same research octane number, in HCCI engines as the intake pressure and temperature are changed. For high intake pressures and low intake temperatures, a sensitivity analysis at the moment of maximum heat release rate shows that the consumption of phenoxy radicals is rate-limiting when a toluene/n-heptane fuel is used, which makes this fuel more resistant to autoignition than the primary reference fuel. Typical CPU times encountered in zero-dimensional calculations were on the order of seconds and minutes in laminar flame speed calculations. Cross reactions between benzylperoxy radicals and n-heptane improved the model predictions of shock tube experiments for {phi}=1.0 and temperatures lower than 800 K for an n-heptane/toluene fuel mixture, but cross reactions had no influence on HCCI simulations. (author)

  11. A mitigation scheme for underwater blast: Experiments and modeling

    NASA Astrophysics Data System (ADS)

    Glascoe, Lee G.; Margraf, Jon; McMichael, Larry; Vandersall, Kevin S.

    2012-03-01

    A novel but relatively easy-to-implement mitigation concept to enforce standoff distance and reduce shock loading on a vertical, partially-submerged structure is evaluated experimentally using scaled aquarium experiments and numerically using a high-fidelity finite element code. Scaled, watertamped explosive experiments were performed using aquariums of different sizes. The effectiveness of different mitigation configurations, including air-filled media and an air gap, is assessed relative to an unmitigated detonation using the same charge weight and standoff distance. Experiments using an airfilled media mitigation concept effectively dampen the explosive response of an aluminum plate and reduce the final displacement at plate center by approximately half. Experiments using an air-gap resulted in a focused water slug hitting the plate, an effect we hypothesize to be due to water encasement of the charge. Finite element simulations used for the initial experimental design compare very well to experiments both spatially and temporally for the unmitigated case and for the air-filled media mitigation; simulations accounting for water encasement bound air gap experiments. Details of numerical and experimental approach are provided as well as a discussion of results.

  12. Hot water, fresh beer, and salt

    NASA Astrophysics Data System (ADS)

    Crawford, Frank S.

    1990-11-01

    In the ``hot chocolate effect'' the best musical scales (those with the finest tone quality, largest range, and best tempo) are obtained by adding salt to a glass of hot water supersaturated with air. Good scales can also be obtained by adding salt to a glass of freshly opened beer (supersaturated with CO2) provided you first (a) get rid of much of the excess CO2 so as to produce smaller, hence slower, rising bubbles, and (b) get rid of the head of foam, which damps the standing wave and ruins the tone quality. Finally the old question, ``Do ionizing particles produce bubbles in fresh beer?'' is answered experimentally.

  13. Uncertainty Analysis with Site Specific Groundwater Models: Experiences and Observations

    SciTech Connect

    Brewer, K.

    2003-07-15

    Groundwater flow and transport predictions are a major component of remedial action evaluations for contaminated groundwater at the Savannah River Site. Because all groundwater modeling results are subject to uncertainty from various causes; quantification of the level of uncertainty in the modeling predictions is beneficial to project decision makers. Complex site-specific models present formidable challenges for implementing an uncertainty analysis.

  14. INNOVATIVE FRESH WATER PRODUCTION PROCESS FOR FOSSIL FUEL PLANTS

    SciTech Connect

    James F. Klausner; Renwei Mei; Yi Li; Mohamed Darwish; Diego Acevedo; Jessica Knight

    2003-09-01

    This report describes the annual progress made in the development and analysis of a Diffusion Driven Desalination (DDD) system, which is powered by the waste heat from low pressure condensing steam in power plants. The desalination is driven by water vapor saturating dry air flowing through a diffusion tower. Liquid water is condensed out of the air/vapor mixture in a direct contact condenser. A thermodynamic analysis demonstrates that the DDD process can yield a fresh water production efficiency of 4.5% based on a feed water inlet temperature of only 50 C. An example is discussed in which the DDD process utilizes waste heat from a 100 MW steam power plant to produce 1.51 million gallons of fresh water per day. The main focus of the initial development of the desalination process has been on the diffusion tower. A detailed mathematical model for the diffusion tower has been described, and its numerical implementation has been used to characterize its performance and provide guidance for design. The analysis has been used to design a laboratory scale diffusion tower, which has been thoroughly instrumented to allow detailed measurements of heat and mass transfer coefficient, as well as fresh water production efficiency. The experimental facility has been described in detail.

  15. Freshness estimation of intact frozen fish using fluorescence spectroscopy and chemometrics of excitation-emission matrix.

    PubMed

    ElMasry, Gamal; Nagai, Hiroto; Moria, Keisuke; Nakazawa, Naho; Tsuta, Mizuki; Sugiyama, Junichi; Okazaki, Emiko; Nakauchi, Shigeki

    2015-10-01

    The current study attempted to provide a convenient, non-invasive and time-saving method to estimate the freshness of intact horse mackerel (Trachurus japonicus) fish in a frozen state using autofluorescence spectroscopy in tandem with multivariate analysis of fluorescence excitation-emission matrices (EEM). The extracted fluorescence data from different freshness conditions were pretreated, masked and reorganized to resolve fish fluorescence spectra from overlapping signals and scattering profiles for detecting and characterizing freshness changes. The real freshness values of the examined fish samples were then traditionally determined by the hard chemical analysis using the high performance liquid chromatography (HPLC) method and expressed as K-values. The fluorescence EEM data and the real freshness values were modeled using partial least square (PLS) regression and a novel algorithm was proposed to identify the ideal combinations of excitation and emission wavelengths being used as perfect predictors. The results revealed that freshness of frozen fish could be accurately predicted with R(2) of 0.89 and root mean square error estimated by cross validation (RMSECV) of 9.66%. This work substantially demonstrated that the autofluorescence spectroscopy associated with the proposed technical approaches has a high potential in non-destructive sensing of fish freshness in the frozen state. PMID:26078142

  16. Experiments and modeling of flow processes in freshwater lenses in layered island aquifers: Analysis of age stratification, travel times and interface propagation

    NASA Astrophysics Data System (ADS)

    Stoeckl, Leonard; Houben, Georg J.; Dose, Eduardo J.

    2015-10-01

    The management of fresh groundwater resources and the delineation of protection zones on islands require a thorough understanding of flow processes within freshwater lenses. Previous studies of freshwater lenses have mainly focused on interface geometries, disregarding flow patterns within the lens. In this study we use physical, analytical and numerical modeling to investigate the influence of vertically and horizontally layered aquifers and variations in recharge on the age stratification, travel times and transient development of freshwater lenses. Four generalized settings were examined in detail on a laboratory-scale. The experiments show significant deviations from homogeneous models. The case of a high permeability layer underlying a layer of lower permeability shows the strongest deviations in the processes investigated here. Water in the more permeable lower layer overtakes water flowing only through the upper layer, causing a bimodal distribution of travel times and a vertical repeating of the age stratification near the coast. The effects of heterogeneities revealed by the physical model experiments are expected to also occur on real islands and have thus to be considered when developing conceptual models for the management of such freshwater lenses.

  17. Subsurface imaging, TAIGER experiments and tectonic models of Taiwan

    NASA Astrophysics Data System (ADS)

    Wu, Francis T.; Kuo-Chen, H.; McIntosh, K. D.

    2014-08-01

    The seismicity, deformation rates and associated erosion in the Taiwan region clearly demonstrate that plate tectonic and orogenic activities are at a high level. Major geologic units can be neatly placed in the plate tectonic context, albeit critical mapping in specific areas is still needed, but the key processes involved in the building of the island remain under discussion. Of the two plates in the vicinity of Taiwan, the Philippine Sea Plate (PSP) is oceanic in its origin while the Eurasian Plate (EUP) is comprised partly of the Asian continental lithosphere and partly of the transitional lithosphere of the South China Sea basin. It is unanimously agreed that the collision of PSP and EU is the cause of the Taiwan orogeny, but several models of the underlying geological processes have been proposed, each with its own evolutionary history and implied subsurface tectonics. TAIGER (TAiwan Integrated GEodynamics Research) crustal- and mantle-imaging experiments recently made possible a new round of testing and elucidation. The new seismic tomography resolved structures under and offshore of Taiwan to a depth of about 200 km. In the upper mantle, the steeply east-dipping high velocity anomalies from southern to central Taiwan are clear, but only the extreme southern part is associated with seismicity; toward the north the seismicity disappears. The crustal root under the Central Range is strongly asymmetrical; using 7.5 km/s as a guide, the steep west-dipping face on the east stands in sharp contrast to a gradual east-dipping face on the west. A smaller root exists under the Coastal Range or slightly to the east of it. Between these two roots lies a well delineated high velocity rise spanning the length from Hualien to Taitung. The 3-D variations in crustal and mantle structures parallel to the trend of the island are closely correlated with the plate tectonic framework of Taiwan. The crust is thickest in the central Taiwan collision zone, and although it thins

  18. A Model for an Introductory Undergraduate Research Experience

    ERIC Educational Resources Information Center

    Canaria, Jeffrey A.; Schoffstall, Allen M.; Weiss, David J.; Henry, Renee M.; Braun-Sand, Sonja B.

    2012-01-01

    An introductory, multidisciplinary lecture-laboratory course linked with a summer research experience has been established to provide undergraduate biology and chemistry majors with the skills needed to be successful in the research laboratory. This three-credit hour course was focused on laboratory skills and was designed to reinforce and develop…

  19. Applying the Job Characteristics Model to the College Education Experience

    ERIC Educational Resources Information Center

    Kass, Steven J.; Vodanovich, Stephen J.; Khosravi, Jasmine Y.

    2011-01-01

    Boredom is one of the most common complaints among university students, with studies suggesting its link to poor grades, drop out, and behavioral problems. Principles borrowed from industrial-organizational psychology may help prevent boredom and enrich the classroom experience. In the current study, we applied the core dimensions of the job…

  20. Experiments and Modeling of Evaporating/Condensing Menisci

    NASA Technical Reports Server (NTRS)

    Plawsky, Joel; Wayner, Peter C., Jr.

    2013-01-01

    Discuss the Constrained Vapor Bubble (CVB) experiment and how it aims to achieve a better understanding of the physics of evaporation and condensation and how they affect cooling processes in microgravity using a remotely controlled microscope and a small cooling device.

  1. Composing a model of outer space through virtual experiences

    NASA Astrophysics Data System (ADS)

    Aguilera, Julieta C.

    2015-03-01

    This paper frames issues of trans-scalar perception in visualization, reflecting on the limits of the human senses, particularly those which are related to space, and describe planetarium shows, presentations, and exhibit experiences of spatial immersion and interaction in real time.

  2. A Stochastic Decision Model for Experiments in Discrimination Learning.

    ERIC Educational Resources Information Center

    Egelston, Richard L.

    Decisions to terminate training for subjects involved with discrete trial experiments in discrimination learning should utilize a probability criterion rather than a deterministic criterion. Furthermore, these decisions should be based upon the number of correct and error responses made by the subject, with the decision made to terminate training…

  3. Methods for Chemical Analysis of Fresh Waters.

    ERIC Educational Resources Information Center

    Golterman, H. L.

    This manual, one of a series prepared for the guidance of research workers conducting studies as part of the International Biological Programme, contains recommended methods for the analysis of fresh water. The techniques are grouped in the following major sections: Sample Taking and Storage; Conductivity, pH, Oxidation-Reduction Potential,…

  4. Dielectric Spectroscopy of Fresh Chicken Breast Meat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The dielectric properties of fresh chicken breast meat were measured at temperatures from 5 to 85 'C over the frequency range from 10 MHz to 1.8 GHz by dielectric spectroscopy techniques with an open-ended coaxial-line probe and impedance analyzer. Samples were cut from both the Pectoralis major an...

  5. Dielectric Spectroscopy of Fresh Chicken Breast Meat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Technical abstract The dielectric properties of fresh chicken breast meat were measured at temperatures from 5 to 85 degrees °C over the frequency range from 10 MHz to 1.8 GHz by dielectric spectroscopy techniques with an open-ended coaxial-line probe and impedance analyzer. Samples were cut from ...

  6. Breeding lettuce for fresh-cut processing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lettuce is increasingly consumed in fresh-cut packaged salads. New cultivars specifically bred for this use can enhance production and processing efficiency and extend shelf life. Cultivars with novel head architectures and leaf traits are being released by private and public breeding programs with ...

  7. Color Quality of Fresh and Processed Strawberries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Color and appearance are very important quality attributes of fresh and processed strawberries (Fragaria × ananassa Duch. ex Rozier). In evaluating new germplasm, the plant breeder considers size, shape, uniformity, along with hue and whether the berries are too light or too dark. The attractive col...

  8. Inactivation of Microbial Contaminants in Fresh Produce

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With the microbial safety of fresh produce of increasing concern, conventional sanitizing treatments need to be supplemented with effective new interventions to inactivate human pathogens. The Produce Safety research project at the US Dept. Agriculture’s Eastern Regional Research Center develops and...

  9. Inactivation of Microbial Contaminants in Fresh Produce

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With the microbial safety of fresh produce of increasing concern, conventional sanitizing treatments need to be supplemented with effective new interventions to inactivate human pathogens. Our research group has shown that inoculation with suppressive microbial communities inhibits the growth of Sal...

  10. Electron cyclotron thruster new modeling results preparation for initial experiments

    NASA Technical Reports Server (NTRS)

    Hooper, E. Bickford

    1993-01-01

    The following topics are discussed: a whistler-based electron cyclotron resonance heating (ECRH) thruster; cross-field coupling in the helicon approximation; wave propagation; wave structure; plasma density; wave absorption; the electron distribution function; isothermal and adiabatic plasma flow; ECRH thruster modeling; a PIC code model; electron temperature; electron energy; and initial experimental tests. The discussion is presented in vugraph form.

  11. TURBULENT DIFFUSION BEHIND VEHICLES: EXPERIMENTS AND VERIFICATION OF ROADWAY MODELS

    EPA Science Inventory

    Tracer gas was released behind model vehicles in a moving floor wind tunnel and sampled extensively at various downwind distances. A numerical model was used to test various expressions for the eddy diffusion coefficients. The best formulation has been incorporated into the ROADW...

  12. Working Towards Explicit Modelling: Experiences of a New Teacher Educator

    ERIC Educational Resources Information Center

    White, Elizabeth

    2011-01-01

    As a new teacher educator of beginner teachers on the Graduate Teacher Programme in a large School of Education in a UK university, I have reflected on how I have been able to develop the effectiveness of modelling good professional practice to student-teachers. In this paper I will present ways in which I have made modelling more explicit, how…

  13. Teaching through Modeling: Four Schools' Experiences in Sustainability Education

    ERIC Educational Resources Information Center

    Higgs, Amy Lyons; McMillan, Victoria M.

    2006-01-01

    In this article, the authors examine how 4 innovative secondary schools model sustainable practices to their students. During school visits, the authors conducted interviews, observed daily life, and reviewed school documents. They found that modeling is a valuable approach to sustainability education, promoting both learning about sustainability…

  14. Pliocene Model Intercomparison Project (PlioMIP): experimental design and boundary conditions (Experiment 2)

    USGS Publications Warehouse

    Haywood, A.M.; Dowsett, H.J.; Robinson, M.M.; Stoll, D.K.; Dolan, A.M.; Lunt, D.J.; Otto-Bliesner, B.; Chandler, M.A.

    2011-01-01

    The Palaeoclimate Modelling Intercomparison Project has expanded to include a model intercomparison for the mid-Pliocene warm period (3.29 to 2.97 million yr ago). This project is referred to as PlioMIP (the Pliocene Model Intercomparison Project). Two experiments have been agreed upon and together compose the initial phase of PlioMIP. The first (Experiment 1) is being performed with atmosphere-only climate models. The second (Experiment 2) utilises fully coupled ocean-atmosphere climate models. Following on from the publication of the experimental design and boundary conditions for Experiment 1 in Geoscientific Model Development, this paper provides the necessary description of differences and/or additions to the experimental design for Experiment 2.

  15. Pliocene Model Intercomparison Project (PlioMIP): Experimental Design and Boundary Conditions (Experiment 2)

    NASA Technical Reports Server (NTRS)

    Haywood, A. M.; Dowsett, H. J.; Robinson, M. M.; Stoll, D. K.; Dolan, A. M.; Lunt, D. J.; Otto-Bliesner, B.; Chandler, M. A.

    2011-01-01

    The Palaeoclimate Modelling Intercomparison Project has expanded to include a model intercomparison for the mid-Pliocene warm period (3.29 to 2.97 million yr ago). This project is referred to as PlioMIP (the Pliocene Model Intercomparison Project). Two experiments have been agreed upon and together compose the initial phase of PlioMIP. The first (Experiment 1) is being performed with atmosphere only climate models. The second (Experiment 2) utilizes fully coupled ocean-atmosphere climate models. Following on from the publication of the experimental design and boundary conditions for Experiment 1 in Geoscientific Model Development, this paper provides the necessary description of differences and/or additions to the experimental design for Experiment 2.

  16. Design and analysis of numerical experiments. [applicable to fully nonlinear, global, equivalent-barotropic model

    NASA Technical Reports Server (NTRS)

    Bowman, Kenneth P.; Sacks, Jerome; Chang, Yue-Fang

    1993-01-01

    Methods for the design and analysis of numerical experiments that are especially useful and efficient in multidimensional parameter spaces are presented. The analysis method, which is similar to kriging in the spatial analysis literature, fits a statistical model to the output of the numerical model. The method is applied to a fully nonlinear, global, equivalent-barotropic dynamical model. The statistical model also provides estimates for the uncertainty of predicted numerical model output, which can provide guidance on where in the parameter space to conduct further experiments, if necessary. The method can provide significant improvements in the efficiency with which numerical sensitivity experiments are conducted.

  17. A controlled experiment in ground water flow model calibration

    USGS Publications Warehouse

    Hill, M.C.; Cooley, R.L.; Pollock, D.W.

    1998-01-01

    Nonlinear regression was introduced to ground water modeling in the 1970s, but has been used very little to calibrate numerical models of complicated ground water systems. Apparently, nonlinear regression is thought by many to be incapable of addressing such complex problems. With what we believe to be the most complicated synthetic test case used for such a study, this work investigates using nonlinear regression in ground water model calibration. Results of the study fall into two categories. First, the study demonstrates how systematic use of a well designed nonlinear regression method can indicate the importance of different types of data and can lead to successive improvement of models and their parameterizations. Our method differs from previous methods presented in the ground water literature in that (1) weighting is more closely related to expected data errors than is usually the case; (2) defined diagnostic statistics allow for more effective evaluation of the available data, the model, and their interaction; and (3) prior information is used more cautiously. Second, our results challenge some commonly held beliefs about model calibration. For the test case considered, we show that (1) field measured values of hydraulic conductivity are not as directly applicable to models as their use in some geostatistical methods imply; (2) a unique model does not necessarily need to be identified to obtain accurate predictions; and (3) in the absence of obvious model bias, model error was normally distributed. The complexity of the test case involved implies that the methods used and conclusions drawn are likely to be powerful in practice.Nonlinear regression was introduced to ground water modeling in the 1970s, but has been used very little to calibrate numerical models of complicated ground water systems. Apparently, nonlinear regression is thought by many to be incapable of addressing such complex problems. With what we believe to be the most complicated synthetic

  18. HCCI experiments with gasoline surrogate fuels modeled by a semidetailed chemical kinetic model

    SciTech Connect

    Andrae, J.C.G.; Head, R.A.

    2009-04-15

    Experiments in a homogeneous charge compression ignition (HCCI) engine have been conducted with four gasoline surrogate fuel blends. The pure components in the surrogate fuels consisted of n-heptane, isooctane, toluene, ethanol and diisobutylene and fuel sensitivities (RON-MON) in the fuel blends ranged from two to nine. The operating conditions for the engine were p{sub in}=0.1 and 0.2 MPa, T{sub in}=80 and 250 C, {phi}=0.25 in air and engine speed 1200 rpm. A semidetailed chemical kinetic model (142 species and 672 reactions) for gasoline surrogate fuels, validated against ignition data from experiments conducted in shock tubes for gasoline surrogate fuel blends at 1.0{<=} p{<=}5.0MPa, 700{<=} T{<=}1200 K and {phi}=1.0, was successfully used to qualitatively predict the HCCI experiments using a single zone modeling approach. The fuel blends that had higher fuel sensitivity were more resistant to autoignition for low intake temperature and high intake pressure and less resistant to autoignition for high intake temperature and low intake pressure. A sensitivity analysis shows that at high intake temperature the chemistry of the fuels ethanol, toluene and diisobutylene helps to advance ignition. This is consistent with the trend that fuels with the least Negative Temperature Coefficient (NTC) behavior show the highest octane sensitivity, and become less resistant to autoignition at high intake temperatures. For high intake pressure the sensitivity analysis shows that fuels in the fuel blend with no NTC behavior consume OH radicals and acts as a radical scavenger for the fuels with NTC behavior. This is consistent with the observed trend of an increase in RON and fuel sensitivity. With data from shock tube experiments in the literature and HCCI modeling in this work, a correlation between the reciprocal pressure exponent on the ignition delay to the fuel sensitivity and volume percentage of single-stage ignition fuel in the fuel blend was found. Higher fuel

  19. Looking beyond Lewis Structures: A General Chemistry Molecular Modeling Experiment Focusing on Physical Properties and Geometry

    ERIC Educational Resources Information Center

    Linenberger, Kimberly J.; Cole, Renee S.; Sarkar, Somnath

    2011-01-01

    We present a guided-inquiry experiment using Spartan Student Version, ready to be adapted and implemented into a general chemistry laboratory course. The experiment provides students an experience with Spartan Molecular Modeling software while discovering the relationships between the structure and properties of molecules. Topics discussed within…

  20. Medium term hurricane catastrophe models: a validation experiment

    NASA Astrophysics Data System (ADS)

    Bonazzi, Alessandro; Turner, Jessica; Dobbin, Alison; Wilson, Paul; Mitas, Christos; Bellone, Enrica

    2013-04-01

    Climate variability is a major source of uncertainty for the insurance industry underwriting hurricane risk. Catastrophe models provide their users with a stochastic set of events that expands the scope of the historical catalogue by including synthetic events that are likely to happen in a defined time-frame. The use of these catastrophe models is widespread in the insurance industry but it is only in recent years that climate variability has been explicitly accounted for. In the insurance parlance "medium term catastrophe model" refers to products that provide an adjusted view of risk that is meant to represent hurricane activity on a 1 to 5 year horizon, as opposed to long term models that integrate across the climate variability of the longest available time series of observations. In this presentation we discuss how a simple reinsurance program can be used to assess the value of medium term catastrophe models. We elaborate on similar concepts as discussed in "Potential Economic Value of Seasonal Hurricane Forecasts" by Emanuel et al. (2012, WCAS) and provide an example based on 24 years of historical data of the Chicago Mercantile Hurricane Index (CHI), an insured loss proxy. Profit and loss volatility of a hypothetical primary insurer are used to score medium term models versus their long term counterpart. Results show that medium term catastrophe models could help a hypothetical primary insurer to improve their financial resiliency to varying climate conditions.

  1. CELSS experiment model and design concept of gas recycle system

    NASA Technical Reports Server (NTRS)

    Nitta, K.; Oguchi, M.; Kanda, S.

    1986-01-01

    In order to prolong the duration of manned missions around the Earth and to expand the human existing region from the Earth to other planets such as a Lunar Base or a manned Mars flight mission, the controlled ecological life support system (CELSS) becomes an essential factor of the future technology to be developed through utilization of space station. The preliminary system engineering and integration efforts regarding CELSS have been carried out by the Japanese CELSS concept study group for clarifying the feasibility of hardware development for Space station experiments and for getting the time phased mission sets after FY 1992. The results of these studies are briefly summarized and the design and utilization methods of a Gas Recycle System for CELSS experiments are discussed.

  2. Mechanical Regulation of Bone Regeneration: Theories, Models, and Experiments

    PubMed Central

    Betts, Duncan Colin; Müller, Ralph

    2014-01-01

    How mechanical forces influence the regeneration of bone remains an open question. Their effect has been demonstrated experimentally, which has allowed mathematical theories of mechanically driven tissue differentiation to be developed. Many simulations driven by these theories have been presented, however, validation of these models has remained difficult due to the number of independent parameters considered. An overview of these theories and models is presented along with a review of experimental studies and the factors they consider. Finally limitations of current experimental data and how this influences modeling are discussed and potential solutions are proposed. PMID:25540637

  3. Variational Water Wave Modelling: from Continuum to Experiment

    NASA Astrophysics Data System (ADS)

    Bokhove, Onno; Kalogirou, Anna

    2015-04-01

    Variational methods are investigated asymptotically and numerically to model water waves in tanks with wave generators. A modified Benney-Luke model is derived using variational techniques including a time-dependent gravitional potential mimicking a removable "sluice gate". As a validation, our modelling results using (dis)continuous Galerkin finite elements will be compared to a soliton splash event resulting after a sluice gate is removed during a finite time in a long water channel with a contraction at its end. Future work will explore these methods for wave-energy devices and ships in modest to heavy seas.

  4. An Acoustic Demonstration Model for CW and Pulsed Spectrosocopy Experiments

    NASA Astrophysics Data System (ADS)

    Starck, Torben; Mäder, Heinrich; Trueman, Trevor; Jäger, Wolfgang

    2009-06-01

    High school and undergraduate students have often difficulties if new concepts are introduced in their physics or chemistry lectures. Lecture demonstrations and references to more familiar analogues can be of great help to the students in such situations. We have developed an experimental setup to demonstrate the principles of cw absorption and pulsed excitation - emission spectroscopies, using acoustical analogues. Our radiation source is a speaker and the detector is a microphone, both controlled by a computer sound card. The acoustical setup is housed in a plexiglas box, which serves as a resonator. It turns out that beer glasses are suitable samples; this also helps to keep the students interested! The instrument is controlled by a LabView program. In a cw experiment, the sound frequency is swept through a certain frequency range and the microphone response is recorded simultaneously as function of frequency. A background signal without sample is recorded, and background subtraction yields the beer glass spectrum. In a pulsed experiment, a short sound pulse is generated and the microphone is used to record the resulting emission signal of the beer glass. A Fourier transformation of the time domain signal gives then the spectrum. We will discuss the experimental setup and show videos of the experiments.

  5. Investigation of models for large-scale meteorological prediction experiments

    NASA Technical Reports Server (NTRS)

    Spar, J.

    1981-01-01

    An attempt is made to compute the contributions of various surface boundary conditions to the monthly mean states generated by the 7 layer, 8 x 10 GISS climate model (Hansen et al., 1980), and also to examine the influence of initial conditions on the model climate simulations. Obvious climatic controls as the shape and rotation of the Earth, the solar radiation, and the dry composition of the atmosphere are fixed, and only the surface boundary conditions are altered in the various climate simulations.

  6. A business process modeling experience in a complex information system re-engineering.

    PubMed

    Bernonville, Stéphanie; Vantourout, Corinne; Fendeler, Geneviève; Beuscart, Régis

    2013-01-01

    This article aims to share a business process modeling experience in a re-engineering project of a medical records department in a 2,965-bed hospital. It presents the modeling strategy, an extract of the results and the feedback experience. PMID:23920743

  7. Experience and Cultural Models Matter: Placing Firm Limits on Childhood Anthropocentrism

    ERIC Educational Resources Information Center

    Waxman, Sandra; Medin, Douglas

    2007-01-01

    This paper builds on Hatano and Inagaki's pioneering work on the role of experience and cultural models in children's biological reasoning. We use a category-based induction task to consider how experience and cultural models shape rural and urban children's patterns of biological reasoning. We discuss the implications of these findings for…

  8. Using a high biomass plant Pennisetum hydridum to phyto-treat fresh municipal sewage sludge.

    PubMed

    Hei, Liang; Lee, Charles C C; Wang, Hui; Lin, Xiao-Yan; Chen, Xiao-Hong; Wu, Qi-Tang

    2016-10-01

    The study was carried out to investigate the use of a high biomass plant, Pennisetum hydridum, to treat municipal sewage sludge (MSS). An experiment composed of plots with four treatments, soil, fresh sludge, soil-sludge mixture and phyto-treated sludge, was conducted. It showed that the plant could not survive directly in fresh MSS when cultivated from stem cuttings. The experiment transplanting the incubated cutting with nurse medium of P. hydridum in soil and fresh MSS, showed that the plants grew normally in fresh MSS. The pilot experiment of P. hydridum and Alocasia macrorrhiza showed that the total yield and nutrient amount of P. hydridum were 9.2 times and 3.6 times more than that of A. macrorrhiza. After plant treatment, MSS was dried, stabilized and suitable to be landfilled or incinerated, with a calorific value of about 5.6MJ/kg (compared to the initial value of 1.9MJ/kg fresh sludge). PMID:26897473

  9. Cardiovascular model for the simulation of exercise, lower body negative pressure, and tilt experiments

    NASA Technical Reports Server (NTRS)

    Croston, R. C.; Fitzjerrell, D. G.

    1974-01-01

    A mathematical model and digital computer simulation of the human cardiovascular system and its controls have been developed to simulate pulsatile dynamic responses to the cardiovascular experiments of the Skylab missions and to selected physiological stresses of manned space flight. Specific model simulations of the bicycle ergometry, lower body negative pressure, and tilt experiments have been developed and verified for 1-g response by comparison with available experimental data. The zero-g simulations of two Skylab experiments are discussed.

  10. Interim Service ISDN Satellite (ISIS) network model for advanced satellite designs and experiments

    NASA Technical Reports Server (NTRS)

    Pepin, Gerard R.; Hager, E. Paul

    1991-01-01

    The Interim Service Integrated Services Digital Network (ISDN) Satellite (ISIS) Network Model for Advanced Satellite Designs and Experiments describes a model suitable for discrete event simulations. A top-down model design uses the Advanced Communications Technology Satellite (ACTS) as its basis. The ISDN modeling abstractions are added to permit the determination and performance for the NASA Satellite Communications Research (SCAR) Program.

  11. Mathematical modelling of microtumour infiltration based on in vitro experiments.

    PubMed

    Luján, Emmanuel; Guerra, Liliana N; Soba, Alejandro; Visacovsky, Nicolás; Gandía, Daniel; Calvo, Juan C; Suárez, Cecilia

    2016-08-01

    The present mathematical models of microtumours consider, in general, volumetric growth and spherical tumour invasion shapes. Nevertheless in many cases, such as in gliomas, a need for more accurate delineation of tumour infiltration areas in a patient-specific manner has arisen. The objective of this study was to build a mathematical model able to describe in a case-specific way as well as to predict in a probabilistic way the growth and the real invasion pattern of multicellular tumour spheroids (in vitro model of an avascular microtumour) immersed in a collagen matrix. The two-dimensional theoretical model was represented by a reaction-convection-diffusion equation that considers logistic proliferation, volumetric growth, a rim with proliferative cells at the tumour surface and invasion with diffusive and convective components. Population parameter values of the model were extracted from the experimental dataset and a shape function that describes the invasion area was derived from each experimental case by image processing. New possible and aleatory shape functions were generated by data mining and Monte Carlo tools by means of a satellite EGARCH model, which were fed with all the shape functions of the dataset. Then the main model is used in two different ways: to reproduce the growth and invasion of a given experimental tumour in a case-specific manner when fed with the corresponding shape function (descriptive simulations) or to generate new possible tumour cases that respond to the general population pattern when fed with an aleatory-generated shape function (predictive simulations). Both types of simulations are in good agreement with empirical data, as it was revealed by area quantification and Bland-Altman analysis. This kind of experimental-numerical interaction has wide application potential in designing new strategies able to predict as much as possible the invasive behaviour of a tumour based on its particular characteristics and microenvironment

  12. The estimation of parameters in nonlinear, implicit measurement error models with experiment-wide measurements

    SciTech Connect

    Anderson, K.K.

    1994-05-01

    Measurement error modeling is a statistical approach to the estimation of unknown model parameters which takes into account the measurement errors in all of the data. Approaches which ignore the measurement errors in so-called independent variables may yield inferior estimates of unknown model parameters. At the same time, experiment-wide variables (such as physical constants) are often treated as known without error, when in fact they were produced from prior experiments. Realistic assessments of the associated uncertainties in the experiment-wide variables can be utilized to improve the estimation of unknown model parameters. A maximum likelihood approach to incorporate measurements of experiment-wide variables and their associated uncertainties is presented here. An iterative algorithm is presented which yields estimates of unknown model parameters and their estimated covariance matrix. Further, the algorithm can be used to assess the sensitivity of the estimates and their estimated covariance matrix to the given experiment-wide variables and their associated uncertainties.

  13. Characteristics of the tensile mechanical properties of fresh and dry forewings of beetles.

    PubMed

    Tuo, Wanyong; Chen, Jinxiang; Wu, Zhishen; Xie, Juan; Wang, Yong

    2016-08-01

    Based on a tensile experiment and observations by scanning electron microscopy (SEM), this study demonstrated the characteristics of the tensile mechanical properties of the fresh and dry forewings of two types of beetles. The results revealed obvious differences in the tensile fracture morphologies and characteristics of the tensile mechanical properties of fresh and dry forewings of Cybister tripunctatus Olivier and Allomyrina dichotoma. For fresh forewings of these two types of beetles, a viscous, flow-like, polymer matrix plastic deformation was observed on the fracture surfaces, with soft morphologies and many fibers being pulled out, whereas on the dry forewings, the tensile fracture surfaces were straightforward, and there were no features resembling those found on the fresh forewings. The fresh forewings exhibited a greater fracture strain than the dry forewings, which was caused by the relative slippage of hydroxyl inter-chain bonds due to the presence of water in the fibers and proteins in the fresh forewings. Our study is the first to demonstrate the phenomenon of sudden stress drops caused by the fracturing of the lower skin because the lower skin fractured before the forewings of A. dichotoma reached their ultimate tensile strength. We also investigated the reasons underlying this phenomenon. This research provides a much better understanding of the mechanical properties of beetle forewings and facilitates the correct selection of study objects for biomimetic materials and development of the corresponding applications. PMID:27157727

  14. Differentiation of fresh and frozen-thawed fish samples using Raman spectroscopy coupled with chemometric analysis.

    PubMed

    Velioğlu, Hasan Murat; Temiz, Havva Tümay; Boyaci, Ismail Hakki

    2015-04-01

    The potential of Raman spectroscopy was investigated in terms of its capability to discriminate the species of the fish samples and determine their freshness according to the number of freezing/thawing cycles they exposed. Species discrimination analysis was carried out on sixty-four fish samples from six different species, namely horse mackerel (Trachurus trachurus), European anchovy (Engraulis encrasicolus), red mullet (Mullus surmuletus), Bluefish (Pomatamus saltatrix), Atlantic salmon (Salmo salar) and flying gurnard (Trigla lucerna). Afterwards, fish samples were exposed to different numbers of freezing/thawing cycles and separated into three batches, namely (i) fresh, (ii) once frozen-thawed (OF) and (iii) twice frozen-thawed (TF) samples, in order to perform the freshness analysis. Raman data collected were used as inputs for chemometric analysis, which enabled us to develop two main PCA models to successfully terminate the studies for both species discrimination and freshness determination analysis. PMID:25442555

  15. Modeling of Spherical Torus Plasmas for Liquid Lithium Wall Experiments

    SciTech Connect

    R. Kaita; S. Jardin; B. Jones; C. Kessel; R. Majeski; J. Spaleta; R. Woolley; L. Zakharo; B. Nelson; M. Ulrickson

    2002-01-29

    Liquid metal walls have the potential to solve first-wall problems for fusion reactors, such as heat load and erosion of dry walls, neutron damage and activation, and tritium inventory and breeding. In the near term, such walls can serve as the basis for schemes to stabilize magnetohydrodynamic (MHD) modes. Furthermore, the low recycling characteristics of lithium walls can be used for particle control. Liquid lithium experiments have already begun in the Current Drive eXperiment-Upgrade (CDX-U). Plasmas limited with a toroidally localized limiter have been investigated, and experiments with a fully toroidal lithium limiter are in progress. A liquid surface module (LSM) has been proposed for the National Spherical Torus Experiment (NSTX). In this larger ST, plasma currents are in excess of 1 MA and a typical discharge radius is about 68 cm. The primary motivation for the LSM is particle control, and options for mounting it on the horizontal midplane or in the divertor region are under consideration. A key consideration is the magnitude of the eddy currents at the location of a liquid lithium surface. During plasma start up and disruptions, the force due to such currents and the magnetic field can force a conducting liquid off of the surface behind it. The Tokamak Simulation Code (TSC) has been used to estimate the magnitude of this effect. This program is a two dimensional, time dependent, free boundary simulation code that solves the MHD equations for an axisymmetric toroidal plasma. From calculations that match actual ST equilibria, the eddy current densities can be determined at the locations of the liquid lithium. Initial results have shown that the effects could be significant, and ways of explicitly treating toroidally local structures are under investigation.

  16. The Physical Mechanisms Governing Drop Coalescence: Models vs Experiments

    NASA Astrophysics Data System (ADS)

    Sprittles, James; Shikhmurzaev, Yulii

    2013-11-01

    The dominant physical mechanisms in the coalescence of liquid drops are identified by utilizing recent advances in experimental and computational techniques that resolve unprecedentedly small spatio-temporal scales. To do so, the predictions of both the ``conventional'' model and the (singularity-free) interface formation model, where the dynamics of an ``internal interface'' trapped between the two bulk phases takes a finite time to disappear, before the conventional model takes over, are compared to experimental measurements on microfluidic scales of the very initial moments of coalescence. Using the full numerical solution of the problem in the framework of each of the two models, we show that the recently reported electrical measurements are better described by the interface formation model. As a by product of our results, the range of validity of scaling laws proposed for the phenomenon is established, with inconsistencies in previous works rectified and particular attention paid to quantifying the external gas' effect on the dynamics. Finally, a new scaling law developed for the inertial regime is shown to capture experimental data from the literature remarkably well.

  17. Laser/plasma theory for microwave modeling experiments. Final report

    SciTech Connect

    Thomson, J J; Divergilio, W F

    1980-01-01

    During the last year, we have carried out theoretical investigations of microwave-plasma interactions in support of both the UCLA program, and the TRW program. The UCLA program concentrated on experimental studies of Stimulated Brillouin Scattering (SBS). We derived a theory which successfully explained the basic features of their experiment. The TRW program was originally conceived of as an investigation of electron heating and thermal transport; however, the subject was later changed to the interaction of SBS and self focusing. The experimental program has not yet started; however, we have developed a theoretical description of the expected interaction.

  18. Stimulated Brillouin scattering in picosecond time scales: Experiments and modeling

    SciTech Connect

    Baldis, H.A.; Villeneuve, D.M.; La Fontaine, B.; Enright, G.D. ); Labaune, C.; Baton, S.; Mounaix, P.; Pesme, D. ); Casanova, M. ); Rozmus, W. )

    1993-09-01

    This paper presents an experimental and theoretical study of stimulated Brillouin scattering (SBS) in laser produced plasma using a laser pump with a duration of 8--10 psec. The experiments were performed in a preformed plasma to minimize the flow velocity and have the same plasma conditions over a large range of laser intensities. The reflectivity was then compared to theoretical results over an intensity range of 10[sup 13]--2[times]10[sup 15] W/cm[sup 2]. A short pulse was used so that the SBS was in the temporally growing regime and saturation was not an issue.

  19. Dynamics of the circulation in the Sea of Marmara: numerical modeling experiments and observations from the Turkish straits system experiment

    NASA Astrophysics Data System (ADS)

    Chiggiato, Jacopo; Jarosz, Ewa; Book, Jeffrey W.; Dykes, James; Torrisi, Lucio; Poulain, Pierre-Marie; Gerin, Riccardo; Horstmann, Jochen; Beşiktepe, Şükrü

    2012-01-01

    During September 2008 and February 2009, the NR/V Alliance extensively sampled the waters of the Sea of Marmara within the framework of the Turkish Straits System (TSS) experiment coordinated by the NATO Undersea Research Centre. The observational effort provided an opportunity to set up realistic numerical experiments for modeling the observed variability of the Marmara Sea upper layer circulation at mesoscale resolution over the entire basin during the trial period, complementing relevant features and forcing factors revealed by numerical model results with information acquired from in situ and remote sensing datasets. Numerical model solutions from realistic runs using the Regional Ocean Modeling System (ROMS) produce a general circulation in the Sea of Marmara that is consistent with previous knowledge of the circulation drawn from past hydrographic measurements, with a westward meandering current associated with a recurrent large anticyclone. Additional idealized numerical experiments illuminate the role various dynamics play in determining the Sea of Marmara circulation and pycnocline structure. Both the wind curl and the strait flows are found to strongly influence the strength and location of the main mesoscale features. Large displacements of the pycnocline depth were observed during the sea trials. These displacements can be interpreted as storm-driven upwelling/downwelling dynamics associated with northeasterly winds; however, lateral advection associated with flow from the Straits also played a role in some displacements.

  20. Modeling and analysis of pinhole occulter experiment: Initial study phase

    NASA Technical Reports Server (NTRS)

    Vandervoort, R. J.

    1985-01-01

    The feasibility of using a generic simulation, TREETOPS, to simulate the Pinhole/Occulter Facility (P/OF) to be tested on the space shuttle was demonstrated. The baseline control system was used to determine the pointing performance of the P/OF. The task included modeling the structure as a three body problem (shuttle-instrument pointing system- P/OP) including the flexibility of the 32 meter P/OF boom. Modeling of sensors, actuators, and control algorithms was also required. Detailed mathematical models for the structure, sensors, and actuators are presented, as well as the control algorithm and corresponding design procedure. Closed loop performance using this controller and computer listings for the simulator are also given.

  1. GPU acceleration experience with RRTMG long wave radiation model

    NASA Astrophysics Data System (ADS)

    Price, Erik; Mielikainen, Jarno; Huang, Bormin; Huang, HungLung A.; Lee, Tsengdar

    2013-10-01

    An Atmospheric radiative transfer model calculates radiative transfer of electromagnetic radiation through a planetary atmosphere. Both shortwave radiance and longwave radiance parameterizations in an atmospheric model calculate radiation fluxes and heating rates in the earth-atmospheric system. One radiative transfer model is the rapid radiative transfer model (RRTM), which calculates of longwave and shortwave atmospheric radiative fluxes and heating rates. Longwave broadband radiative transfer code for general circulation model (GCM) applications, RRTMG, is based on the single-column reference code, RRTM. The RRTMG is a validated, correlated k-distribution band model for the calculation of longwave and shortwave atmospheric radiative fluxes and heating rates. The focus of this paper is on the RRTMG long wave (RRTMG_LW) model. In order to improve computational efficiency, RRTMG_LW incorporates several modifications compared to RRTM. In RRTM_LW there are 16 g points in each of the spectral bands for a total of 256 g points. In RRTMG_LW, the number of g points in each spectral band varies from 2 to 16 depending on the absorption in each band. RRTMG_LW employs a computationally efficient correlated-k method for radiative transfer calculations. It contains 16 spectral bands with various number of quadrature points (g points) in each of the bands. In total, there are 140 g points. The radiative effects of all significant atmospheric gases are included in RRTMG_LW. Active gas absorbers include H2O, O3, CO2, CH4, N2O, O2 and four types of halocarbons: CFC-11, CFC-12, CFC-22, and CCL4. RRTMG_LW also treats the absorption and scattering from liquid and ice clouds and aerosols. For cloudysky radiative transfer, a maximum-random cloud overlapping scheme is used. Small scale cloud variability, such as cloud fraction and the vertical overlap of clouds can be represented using a statistical technique in RRTMG_LW. Due to its accuracy, RRTMG_LW has been implemented operationally

  2. Compressive behavior of a turtle's shell: experiment, modeling, and simulation.

    PubMed

    Damiens, R; Rhee, H; Hwang, Y; Park, S J; Hammi, Y; Lim, H; Horstemeyer, M F

    2012-02-01

    The turtle's shell acts as a protective armor for the animal. By analyzing a turtle shell via finite element analysis, one can obtain the strength and stiffness attributes to help design man-made armor. As such, finite element analysis was performed on a Terrapene carolina box turtle shell. Experimental data from compression tests were generated to provide insight into the scute through-thickness behavior of the turtle shell. Three regimes can be classified in terms of constitutive modeling: linear elastic, perfectly inelastic, and densification regions, where hardening occurs. For each regime, we developed a model that comprises elasticity and densification theory for porous materials and obtained all the material parameters by correlating the model with experimental data. The different constitutive responses arise as the deformation proceeded through three distinctive layers of the turtle shell carapace. Overall, the phenomenological stress-strain behavior is similar to that of metallic foams. PMID:22301179

  3. Using MIMIC models to examine the relationship between current smoking and early smoking experiences

    PubMed Central

    Pomerleau, Cynthia S.; Neuman, Rosalind J.; Pomerleau, Ovide F.

    2009-01-01

    Introduction The present study expands previous research on early experiences with tobacco by using a Multiple Indicator Multiple Causes (MIMIC) model, which permits combining indicators tapping into pleasant experiences into one latent construct and those indicators of unpleasant experiences into another latent construct. Methods A sample of 458 participants was recruited via newspaper advertisements. Response to early experimentation with cigarettes was assessed using the Early Smoking Experiences questionnaire, in which participants were asked the following question: “The first time you tried cigarettes, did you experience any of the following? (pleasurable and displeasurable sensations [overall], pleasurable rush or buzz, dizziness, relaxation, nausea, cough, difficulty inhaling).” These experiences were rated on a scale ranging from 1 = none to 4 = intense. Results The MIMIC model revealed that current smoking status and age of initial experimentation with cigarettes were significantly associated with both early pleasant and unpleasant experiences (p < .05). African Americans were less likely than Whites to have early unpleasant experiences (p < .05). No association was found between race and early pleasant experiences. Discussion Our findings are consistent with the inferences that pleasant experiences in response to early experimentation with smoking lead to regular smoking and that positive experiences play a stronger role than negative experiences in the transition to regular smoking. Our study also demonstrates that the MIMIC model is pertinent and practicable in nicotine and smoking research. We recommend it as a useful tool for identifying endophenotypes related to nicotine dependence and tobacco use latent constructs. PMID:19578152

  4. Tapped granular column dynamics: simulations, experiments and modeling

    NASA Astrophysics Data System (ADS)

    Rosato, A. D.; Zuo, L.; Blackmore, D.; Wu, H.; Horntrop, D. J.; Parker, D. J.; Windows-Yule, C.

    2016-07-01

    This paper communicates the results of a synergistic investigation that initiates our long term research goal of developing a continuum model capable of predicting a variety of granular flows. We consider an ostensibly simple system consisting of a column of inelastic spheres subjected to discrete taps in the form of half sine wave pulses of amplitude a/ d and period τ . A three-pronged approach is used, consisting of discrete element simulations based on linear loading-unloading contacts, experimental validation, and preliminary comparisons with our continuum model in the form of an integro-partial differential equation.

  5. Dose-response model for teratological experiments involving quantal responses

    SciTech Connect

    Rai, K.; Van Ryzin, J.

    1985-03-01

    This paper introduces a dose-response model for teratological quantal response data where the probability of response for an offspring from a female at a given dose varies with the litter size. The maximum likelihood estimators for the parameters of the model are given as the solution of a nonlinear iterative algorithm. Two methods of low-dose extrapolation are presented, one based on the litter size distribution and the other a conservative method. The resulting procedures are then applied to a teratological data set from the literature.

  6. EAST alternative magnetic configurations: modelling and first experiments

    NASA Astrophysics Data System (ADS)

    Calabrò, G.; Xiao, B. J.; Chen, S. L.; Duan, Y. M.; Guo, Y.; Li, J. G.; Liu, L.; Luo, Z. P.; Wang, L.; Xu, J.; Zhang, B.; Albanese, R.; Ambrosino, R.; Crisanti, F.; Pericoli Ridolfini, V.; Villone, F.; Viola, B.; Barbato, L.; De Magistris, M.; De Tommasi, G.; Giovannozzi, E.; Mastrostefano, S.; Minucci, S.; Pironti, A.; Ramogida, G.; Tuccillo, A. A.; Zagórski, R.

    2015-08-01

    Heat and particle loads on the plasma facing components are among the most challenging issues to be solved for a reactor design. Alternative magnetic configurations may enable tokamak operation with a lower peak heat load than a standard single null (SN) divertor. This papers reports on the creation and control of one of such alternatives: a two-null nearby divertor configuration. An important element of this study is that this two-null divertor was produced on a large superconducting tokamak as an experimental advanced superconducting tokamak. A preliminary experiment with the second null forming a configuration with significant distance between the two nulls and a contracting geometry near the target plates was performed in 2014. These configurations have been designed using the FIXFREE code and optimized with CREATE-NL tools and are discussed in the paper. Predictive edge simulations using the TECXY code are also presented by comparing the advanced divertor and SN configuration. Finally, the experimental results of ohmic and low confinement (L-mode) two-null divertor and SN discharges and interpretative two-dimensional edge simulations are discussed. Future experiments will be devoted to varying the distance between the two nulls in high confinement (H-mode) discharges.

  7. Brain tumor imaging of rat fresh tissue using terahertz spectroscopy

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Sayuri; Fukushi, Yasuko; Kubota, Oichi; Itsuji, Takeaki; Ouchi, Toshihiko; Yamamoto, Seiji

    2016-07-01

    Tumor imaging by terahertz spectroscopy of fresh tissue without dye is demonstrated using samples from a rat glioma model. The complex refractive index spectrum obtained by a reflection terahertz time-domain spectroscopy system can discriminate between normal and tumor tissues. Both the refractive index and absorption coefficient of tumor tissues are higher than those of normal tissues and can be attributed to the higher cell density and water content of the tumor region. The results of this study indicate that terahertz technology is useful for detecting brain tumor tissue.

  8. Brain tumor imaging of rat fresh tissue using terahertz spectroscopy

    PubMed Central

    Yamaguchi, Sayuri; Fukushi, Yasuko; Kubota, Oichi; Itsuji, Takeaki; Ouchi, Toshihiko; Yamamoto, Seiji

    2016-01-01

    Tumor imaging by terahertz spectroscopy of fresh tissue without dye is demonstrated using samples from a rat glioma model. The complex refractive index spectrum obtained by a reflection terahertz time-domain spectroscopy system can discriminate between normal and tumor tissues. Both the refractive index and absorption coefficient of tumor tissues are higher than those of normal tissues and can be attributed to the higher cell density and water content of the tumor region. The results of this study indicate that terahertz technology is useful for detecting brain tumor tissue. PMID:27456312

  9. Social Modeling Influences on Pain Experience and Behaviour.

    ERIC Educational Resources Information Center

    Craig, Kenneth D.

    The impact of exposure to social models displaying variably tolerant pain behaviour on observers' expressions of pain is examined. Findings indicate substantial effects on verbal reports of pain, avoidance behaviour, psychophysiological indices, power function parameters, and sensory decision theory indices. Discussion centers on how social models…

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

    ERIC Educational Resources Information Center

    Tsangaridou, Niki; Genethliou, Nicholas

    2016-01-01

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

  11. Observing system experiments with an ionospheric electrodynamics model

    NASA Astrophysics Data System (ADS)

    Durazo, J.; Kostelich, E.; Mahalov, A.; Tang, W.

    2016-04-01

    We assess the performance of an ensemble Kalman filter for data assimilation and forecasting of ion density in a model of the ionosphere given noisy observations of varying sparsity. The domain of the numerical model is a mid-latitude ionosphere between 80 and 440 km. This domain includes the D-E layers and the peak in the F layer in the ionosphere. The model simulates the time evolution of an ion density field and the coupled electrostatic potential as charge-neutral winds from gravity waves propagate up from the stratosphere. Forecasts are generated for an ensemble of initial conditions, and synthetic observations, which are generated at random locations in the model domain, are assimilated into the ensemble at time intervals corresponding to about a half-period of the gravity wave. The data assimilation scheme, called the local ensemble transform Kalman filter (LETKF), incorporates observations within a fixed radius of each grid point to compute a unique linear combination of the forecast ensembles at each grid point. The collection of updated grid points forms the updated initial conditions (analysis ensemble) for the next forecast. Even when the observation density is spatially sparse, accurate analyses of the ion density still can be obtained, but the results depend on the size of the local region used. The LETKF is robust to large levels of Gaussian noise in the observations. Our results suggest that the LETKF merits consideration as a data assimilation scheme for space weather forecasting.

  12. A new adaptive hybrid electromagnetic damper: modelling, optimization, and experiment

    NASA Astrophysics Data System (ADS)

    Asadi, Ehsan; Ribeiro, Roberto; Behrad Khamesee, Mir; Khajepour, Amir

    2015-07-01

    This paper presents the development of a new electromagnetic hybrid damper which provides regenerative adaptive damping force for various applications. Recently, the introduction of electromagnetic technologies to the damping systems has provided researchers with new opportunities for the realization of adaptive semi-active damping systems with the added benefit of energy recovery. In this research, a hybrid electromagnetic damper is proposed. The hybrid damper is configured to operate with viscous and electromagnetic subsystems. The viscous medium provides a bias and fail-safe damping force while the electromagnetic component adds adaptability and the capacity for regeneration to the hybrid design. The electromagnetic component is modeled and analyzed using analytical (lumped equivalent magnetic circuit) and electromagnetic finite element method (FEM) (COMSOL® software package) approaches. By implementing both modeling approaches, an optimization for the geometric aspects of the electromagnetic subsystem is obtained. Based on the proposed electromagnetic hybrid damping concept and the preliminary optimization solution, a prototype is designed and fabricated. A good agreement is observed between the experimental and FEM results for the magnetic field distribution and electromagnetic damping forces. These results validate the accuracy of the modeling approach and the preliminary optimization solution. An analytical model is also presented for viscous damping force, and is compared with experimental results The results show that the damper is able to produce damping coefficients of 1300 and 0-238 N s m-1 through the viscous and electromagnetic components, respectively.

  13. Modelling Drug Administration Regimes for Asthma: A Romanian Experience

    ERIC Educational Resources Information Center

    Andras, Szilard; Szilagyi, Judit

    2010-01-01

    In this article, we present a modelling activity, which was a part of the project DQME II (Developing Quality in Mathematics Education, for more details see http://www.dqime.uni-dortmund.de) and some general observations regarding the maladjustments and rational errors arising in such type of activities.

  14. Redesigning Supervision: Alternative Models for Student Teaching and Field Experiences

    ERIC Educational Resources Information Center

    Rodgers, Adrian; Jenkins, Deborah Bainer

    2010-01-01

    In "Redesigning Supervision", active professionals in teacher education and professional development share research-based, alternative models for restructuring the way pre-service teachers are supervised. The authors examine the methods currently used and discuss how teacher educators have striven to change or renew these procedures. They then…

  15. The South African Experience: Beyond the CIDA Model

    ERIC Educational Resources Information Center

    Bruton, John M.

    2008-01-01

    The Community and Individual Development Association (CIDA) City Campus is presented by Heaton as an innovative African alternative to traditional business education. However, he considers the model in isolation from the unique educational and economic circumstances of postapartheid South Africa. As a response, this article goes beyond the CIDA…

  16. Model-Driven Design: Systematically Building Integrated Blended Learning Experiences

    ERIC Educational Resources Information Center

    Laster, Stephen

    2010-01-01

    Developing and delivering curricula that are integrated and that use blended learning techniques requires a highly orchestrated design. While institutions have demonstrated the ability to design complex curricula on an ad-hoc basis, these projects are generally successful at a great human and capital cost. Model-driven design provides a…

  17. Tutoring and Multi-Agent Systems: Modeling from Experiences

    ERIC Educational Resources Information Center

    Bennane, Abdellah

    2010-01-01

    Tutoring systems become complex and are offering varieties of pedagogical software as course modules, exercises, simulators, systems online or offline, for single user or multi-user. This complexity motivates new forms and approaches to the design and the modelling. Studies and research in this field introduce emergent concepts that allow the…

  18. Integrated modeling applications for tokamak experiments with OMFIT

    NASA Astrophysics Data System (ADS)

    Meneghini, O.; Smith, S. P.; Lao, L. L.; Izacard, O.; Ren, Q.; Park, J. M.; Candy, J.; Wang, Z.; Luna, C. J.; Izzo, V. A.; Grierson, B. A.; Snyder, P. B.; Holland, C.; Penna, J.; Lu, G.; Raum, P.; McCubbin, A.; Orlov, D. M.; Belli, E. A.; Ferraro, N. M.; Prater, R.; Osborne, T. H.; Turnbull, A. D.; Staebler, G. M.

    2015-08-01

    One modeling framework for integrated tasks (OMFIT) is a comprehensive integrated modeling framework which has been developed to enable physics codes to interact in complicated workflows, and support scientists at all stages of the modeling cycle. The OMFIT development follows a unique bottom-up approach, where the framework design and capabilities organically evolve to support progressive integration of the components that are required to accomplish physics goals of increasing complexity. OMFIT provides a workflow for easily generating full kinetic equilibrium reconstructions that are constrained by magnetic and motional Stark effect measurements, and kinetic profile information that includes fast-ion pressure modeled by a transport code. It was found that magnetic measurements can be used to quantify the amount of anomalous fast-ion diffusion that is present in DIII-D discharges, and provide an estimate that is consistent with what would be needed for transport simulations to match the measured neutron rates. OMFIT was used to streamline edge-stability analyses, and evaluate the effect of resonant magnetic perturbation (RMP) on the pedestal stability, which have been found to be consistent with the experimental observations. The development of a five-dimensional numerical fluid model for estimating the effects of the interaction between magnetohydrodynamic (MHD) and microturbulence, and its systematic verification against analytic models was also supported by the framework. OMFIT was used for optimizing an innovative high-harmonic fast wave system proposed for DIII-D. For a parallel refractive index {{n}\\parallel}>3 , the conditions for strong electron-Landau damping were found to be independent of launched {{n}\\parallel} and poloidal angle. OMFIT has been the platform of choice for developing a neural-network based approach to efficiently perform a non-linear multivariate regression of local transport fluxes as a function of local dimensionless parameters

  19. Theoretical transport modeling of Ohmic cold pulse experiments

    NASA Astrophysics Data System (ADS)

    Kinsey, J. E.; Waltz, R. E.; St. John, H. E.

    1998-11-01

    The response of several theory-based transport models in Ohmically heated tokamak discharges to rapid edge cooling due to trace impurity injection is studied. Results are presented for the Institute for Fusion Studies—Princeton Plasma Physics Laboratory (IFS/PPPL), gyro-Landau-fluid (GLF23), Multi-mode (MM), and the Itoh-Itoh-Fukuyama (IIF) transport models with an emphasis on results from the Texas Experimental Tokamak (TEXT) [K. W. Gentle, Nucl. Technol./Fusion 1, 479 (1981)]. It is found that critical gradient models containing a strong ion and electron temperature ratio dependence can exhibit behavior that is qualitatively consistent with experimental observation while depending solely on local parameters. The IFS/PPPL model yields the strongest response and demonstrates both rapid radial pulse propagation and a noticeable increase in the central electron temperature following a cold edge temperature pulse (amplitude reversal). Furthermore, the amplitude reversal effect is predicted to diminish with increasing electron density and auxiliary heating in agreement with experimental data. An Ohmic pulse heating effect due to rearrangement of the current profile is shown to contribute to the rise in the core electron temperature in TEXT, but not in the Joint European Tokamak (JET) [A. Tanga and the JET Team, in Plasma Physics and Controlled Nuclear Fusion Research 1986 (International Atomic Energy Agency, Vienna, 1987), Vol. 1, p. 65] and the Tokamak Fusion Test Reactor (TFTR) [R. J. Hawryluk, V. Arunsalam, M. G. Bell et al., in Plasma Physics and Controlled Nuclear Fusion Research 1986 (International Atomic Energy Agency, Vienna, 1987), Vol. 1, p. 51]. While this phenomenon is not necessarily a unique signature of a critical gradient, there is sufficient evidence suggesting that the apparent plasma response to edge cooling may not require any underlying nonlocal mechanism and may be explained within the context of the intrinsic properties of electrostatic drift

  20. Metabolomics analysis of shucked mussels' freshness.

    PubMed

    Aru, Violetta; Pisano, Maria Barbara; Savorani, Francesco; Engelsen, Søren Balling; Cosentino, Sofia; Cesare Marincola, Flaminia

    2016-08-15

    In this work a NMR metabolomics approach was applied to analyze changes in the metabolic profile of the bivalve mollusk Mytilus galloprovincialis upon storage at 0°C and 4°C for 10 and 6 days, respectively. The most significant microbial groups involved in spoilage of mussels were also investigated. The time-related metabolic signature of mussels was analysed by Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA) which revealed a clear discrimination between the fresh samples and those stored at 0°C and 4°C. The results evidenced a noticeable increase in acetate, lactate, succinate, alanine, branched chain amino acids, trimethylamine and a progressive decline of osmolytes like betaine, homarine and taurine during storage. Exploration of the correlations of these metabolites with microbial counts suggested their use as potential biomarkers of spoilage. The results support the use of NMR metabolomics as a valuable tool to provide information on seafood freshness. PMID:27006214

  1. Hot water, fresh beer, and salt

    SciTech Connect

    Crawford, F.S. Physics Department, University of California, Berkeley, CA )

    1990-11-01

    In the hot chocolate effect'' the best musical scales (those with the finest tone quality, largest range, and best tempo) are obtained by adding salt to a glass of hot water supersaturated with air. Good scales can also be obtained by adding salt to a glass of freshly opened beer (supersaturated with CO{sub 2}) provided you first (a) get rid of much of the excess CO{sub 2} so as to produce smaller, hence slower, rising bubbles, and (b) get rid of the head of foam, which damps the standing wave and ruins the tone quality. Finally the old question, Do ionizing particles produce bubbles in fresh beer '' is answered experimentally.

  2. Little Earth Experiment: An instrument to model planetary cores.

    PubMed

    Aujogue, Kélig; Pothérat, Alban; Bates, Ian; Debray, François; Sreenivasan, Binod

    2016-08-01

    In this paper, we present a new experimental facility, Little Earth Experiment, designed to study the hydrodynamics of liquid planetary cores. The main novelty of this apparatus is that a transparent electrically conducting electrolyte is subject to extremely high magnetic fields (up to 10 T) to produce electromagnetic effects comparable to those produced by moderate magnetic fields in planetary cores. This technique makes it possible to visualise for the first time the coupling between the principal forces in a convection-driven dynamo by means of Particle Image Velocimetry (PIV) in a geometry relevant to planets. We first present the technology that enables us to generate these forces and implement PIV in a high magnetic field environment. We then show that the magnetic field drastically changes the structure of convective plumes in a configuration relevant to the tangent cylinder region of the Earth's core. PMID:27587138

  3. Little Earth Experiment: An instrument to model planetary cores

    NASA Astrophysics Data System (ADS)

    Aujogue, Kélig; Pothérat, Alban; Bates, Ian; Debray, François; Sreenivasan, Binod

    2016-08-01

    In this paper, we present a new experimental facility, Little Earth Experiment, designed to study the hydrodynamics of liquid planetary cores. The main novelty of this apparatus is that a transparent electrically conducting electrolyte is subject to extremely high magnetic fields (up to 10 T) to produce electromagnetic effects comparable to those produced by moderate magnetic fields in planetary cores. This technique makes it possible to visualise for the first time the coupling between the principal forces in a convection-driven dynamo by means of Particle Image Velocimetry (PIV) in a geometry relevant to planets. We first present the technology that enables us to generate these forces and implement PIV in a high magnetic field environment. We then show that the magnetic field drastically changes the structure of convective plumes in a configuration relevant to the tangent cylinder region of the Earth's core.

  4. Experience with mixed MPI/threaded programming models

    SciTech Connect

    May, J M; Supinski, B R

    1999-04-01

    A shared memory cluster is a parallel computer that consists of multiple nodes connected through an interconnection network. Each node is a symmetric multiprocessor (SMP) unit in which multiple CPUs share uniform access to a pool of main memory. The SGI Origin 2000, Compaq (formerly DEC) AlphaServer Cluster, and recent IBM RS6000/SP systems are all variants of this architecture. The SGI Origin 2000 has hardware that allows tasks running on any processor to access any main memory location in the system, so all the memory in the nodes forms a single shared address space. This is called a nonuniform memory access (NUMA) architecture because it gives programs a single shared address space, but the access time to different memory locations varies. In the IBM and Compaq systems, each node's memory forms a separate address space, and tasks communicate between nodes by passing messages or using other explicit mechanisms. Many large parallel codes use standard MPI calls to exchange data between tasks in a parallel job, and this is a natural programming model for distributed memory architectures. On a shared memory architecture, message passing is unnecessary if the code is written to use multithreading: threads run in parallel on different processors, and they exchange data simply by reading and writing shared memory locations. Shared memory clusters combine architectural elements of both distributed memory and shared memory systems, and they support both message passing and multithreaded programming models. Application developers are now trying to determine which programming model is best for these machines. This paper presents initial results of a study aimed at answering that question. We interviewed developers representing nine scientific code groups at Lawrence Livermore National Laboratory (LLNL). All of these groups are attempting to optimize their codes to run on shared memory clusters, specifically the IBM and DEC platforms at LLNL. This paper will focus on ease

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

    ERIC Educational Resources Information Center

    Blikstein, Paulo; Fuhrmann, Tamar; Salehi, Shima

    2016-01-01

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

  6. The human operator in manual preview tracking /an experiment and its modeling via optimal control/

    NASA Technical Reports Server (NTRS)

    Tomizuka, M.; Whitney, D. E.

    1976-01-01

    A manual preview tracking experiment and its results are presented. The preview drastically improves the tracking performance compared to zero-preview tracking. Optimal discrete finite preview control is applied to determine the structure of a mathematical model of the manual preview tracking experiment. Variable parameters in the model are adjusted to values which are consistent to the published data in manual control. The model with the adjusted parameters is found to be well correlated to the experimental results.

  7. Three-Dimensional Numerical Modeling of Magnetohydrodynamic Augmented Propulsion Experiment

    NASA Technical Reports Server (NTRS)

    Turner, M. W.; Hawk, C. W.; Litchford, R. J.

    2009-01-01

    Over the past several years, NASA Marshall Space Flight Center has engaged in the design and development of an experimental research facility to investigate the use of diagonalized crossed-field magnetohydrodynamic (MHD) accelerators as a possible thrust augmentation device for thermal propulsion systems. In support of this effort, a three-dimensional numerical MHD model has been developed for the purpose of analyzing and optimizing accelerator performance and to aid in understanding critical underlying physical processes and nonideal effects. This Technical Memorandum fully summarizes model development efforts and presents the results of pretest performance optimization analyses. These results indicate that the MHD accelerator should utilize a 45deg diagonalization angle with the applied current evenly distributed over the first five inlet electrode pairs. When powered at 100 A, this configuration is expected to yield a 50% global efficiency with an 80% increase in axial velocity and a 50% increase in centerline total pressure.

  8. Modulated photothermal radiometry applied to semitransparent samples: Models and experiments

    NASA Astrophysics Data System (ADS)

    André, S.; Rémy, B.; Maillet, D.; Degiovanni, A.; Serra, J.-J.

    2004-09-01

    Mathematical modeling is presented of the combined conductive and radiative heat transfer occurring in a semitransparent material (STM) subjected to a periodic heat flux. The models rely on the quadrupole method, which is a very powerful tool to obtain analytical solutions in the Fourier or Laplace domain. Photoacoustic or photothermal radiometry techniques are reviewed. Two groups of methods are discussed depending on whether the sample has natural or opaque interfaces to simulate radiative exchanges with the surroundings. The metrological problem of measuring the phonic thermal diffusivity of semitransparent materials is investigated. Theoretical simulations are given. They explain some typical features of the phase-lag signal of temperature responses. Experimental measurements on pure silica validate the results and prove that these methods are efficient for the thermal characterization of STM.

  9. Experiences Using Lightweight Formal Methods for Requirements Modeling

    NASA Technical Reports Server (NTRS)

    Easterbrook, Steve; Lutz, Robyn; Covington, Rick; Kelly, John; Ampo, Yoko; Hamilton, David

    1997-01-01

    This paper describes three case studies in the lightweight application of formal methods to requirements modeling for spacecraft fault protection systems. The case studies differ from previously reported applications of formal methods in that formal methods were applied very early in the requirements engineering process, to validate the evolving requirements. The results were fed back into the projects, to improve the informal specifications. For each case study, we describe what methods were applied, how they were applied, how much effort was involved, and what the findings were. In all three cases, formal methods enhanced the existing verification and validation processes, by testing key properties of the evolving requirements, and helping to identify weaknesses. We conclude that the benefits gained from early modeling of unstable requirements more than outweigh the effort needed to maintain multiple representations.

  10. Flow interaction experiment. Volume 2: Aerothermal modeling, phase 2

    NASA Technical Reports Server (NTRS)

    Nikjooy, M.; Mongia, H. C.; Sullivan, J. P.; Murthy, S. N. B.

    1993-01-01

    An experimental and computational study is reported for the flow of a turbulent jet discharging into a rectangular enclosure. The experimental configurations consisting of primary jets only, annular jets only, and a combination of annular and primary jets are investigated to provide a better understanding of the flow field in an annular combustor. A laser Doppler velocimeter is used to measure mean velocity and Reynolds stress components. Major features of the flow field include recirculation, primary and annular jet interaction, and high turbulence. A significant result from this study is the effect the primary jets have on the flow field. The primary jets are seen to create statistically larger recirculation zones and higher turbulence levels. In addition, a technique called marker nephelometry is used to provide mean concentration values in the model combustor. Computations are performed using three levels of turbulence closures, namely k-epsilon model, algebraic second moment (ASM), and differential second moment (DSM) closure. Two different numerical schemes are applied. One is the lower-order power-law differencing scheme (PLDS) and the other is the higher-order flux-spline differencing scheme (FSDS). A comparison is made of the performance of these schemes. The numerical results are compared with experimental data. For the cases considered in this study, the FSDS is more accurate than the PLDS. For a prescribed accuracy, the flux-spline scheme requires a far fewer number of grid points. Thus, it has the potential for providing a numerical error-free solution, especially for three-dimensional flows, without requiring an excessively fine grid. Although qualitatively good comparison with data was obtained, the deficiencies regarding the modeled dissipation rate (epsilon) equation, pressure-strain correlation model, and the inlet epsilon profile and other critical closure issues need to be resolved before one can achieve the degree of accuracy required to

  11. Flow interaction experiment. Volume 1: Aerothermal modeling, phase 2

    NASA Technical Reports Server (NTRS)

    Nikjooy, M.; Mongia, H. C.; Sullivan, J. P.; Murthy, S. N. B.

    1993-01-01

    An experimental and computational study is reported for the flow of a turbulent jet discharging into a rectangular enclosure. The experimental configurations consisting of primary jets only, annular jets only, and a combination of annular and primary jets are investigated to provide a better understanding of the flow field in an annular combustor. A laser Doppler velocimeter is used to measure mean velocity and Reynolds stress components. Major features of the flow field include recirculation, primary and annular jet interaction, and high turbulence. A significant result from this study is the effect the primary jets have on the flow field. The primary jets are seen to create statistically larger recirculation zones and higher turbulence levels. In addition, a technique called marker nephelometry is used to provide mean concentration values in the model combustor. Computations are performed using three levels of turbulence closures, namely k-epsilon model, algebraic second moment (ASM), and differential second moment (DSM) closure. Two different numerical schemes are applied. One is the lower-order power-law differencing scheme (PLDS) and the other is the higher-order flux-spline differencing scheme (FSDS). A comparison is made of the performance of these schemes. The numerical results are compared with experimental data. For the cases considered in this study, the FSDS is more accurate than the PLDS. For a prescribed accuracy, the flux-spline scheme requires a far fewer number of grid points. Thus, it has the potential for providing a numerical error-free solution, especially for three-dimensional flows, without requiring an excessively fine grid. Although qualitatively good comparison with data was obtained, the deficiencies regarding the modeled dissipation rate (epsilon) equation, pressure-strain correlation model, and the inlet epsilon profile and other critical closure issues need to be resolved before one can achieve the degree of accuracy required to

  12. Integrated modeling of cryogenic layered highfoot experiments at the NIF

    NASA Astrophysics Data System (ADS)

    Kritcher, A. L.; Hinkel, D. E.; Callahan, D. A.; Hurricane, O. A.; Clark, D.; Casey, D. T.; Dewald, E. L.; Dittrich, T. R.; Döppner, T.; Barrios Garcia, M. A.; Haan, S.; Berzak Hopkins, L. F.; Jones, O.; Landen, O.; Ma, T.; Meezan, N.; Milovich, J. L.; Pak, A. E.; Park, H.-S.; Patel, P. K.; Ralph, J.; Robey, H. F.; Salmonson, J. D.; Sepke, S.; Spears, B.; Springer, P. T.; Thomas, C. A.; Town, R.; Celliers, P. M.; Edwards, M. J.

    2016-05-01

    Integrated radiation hydrodynamic modeling in two dimensions, including the hohlraum and capsule, of layered cryogenic HighFoot Deuterium-Tritium (DT) implosions on the NIF successfully predicts important data trends. The model consists of a semi-empirical fit to low mode asymmetries and radiation drive multipliers to match shock trajectories, one dimensional inflight radiography, and time of peak neutron production. Application of the model across the HighFoot shot series, over a range of powers, laser energies, laser wavelengths, and target thicknesses predicts the neutron yield to within a factor of two for most shots. The Deuterium-Deuterium ion temperatures and the DT down scattered ratios, ratio of (10-12)/(13-15) MeV neutrons, roughly agree with data at peak fuel velocities <340 km/s and deviate at higher peak velocities, potentially due to flows and neutron scattering differences stemming from 3D or capsule support tent effects. These calculations show a significant amount alpha heating, 1-2.5× for shots where the experimental yield is within a factor of two, which has been achieved by increasing the fuel kinetic energy. This level of alpha heating is consistent with a dynamic hot spot model that is matched to experimental data and as determined from scaling of the yield with peak fuel velocity. These calculations also show that low mode asymmetries become more important as the fuel velocity is increased, and that improving these low mode asymmetries can result in an increase in the yield by a factor of several.

  13. Flooding Experiments and Modeling for Improved Reactor Safety

    SciTech Connect

    Solmos, M., Hogan, K.J., VIerow, K.

    2008-09-14

    Countercurrent two-phase flow and “flooding” phenomena in light water reactor systems are being investigated experimentally and analytically to improve reactor safety of current and future reactors. The aspects that will be better clarified are the effects of condensation and tube inclination on flooding in large diameter tubes. The current project aims to improve the level of understanding of flooding mechanisms and to develop an analysis model for more accurate evaluations of flooding in the pressurizer surge line of a Pressurized Water Reactor (PWR). Interest in flooding has recently increased because Countercurrent Flow Limitation (CCFL) in the AP600 pressurizer surge line can affect the vessel refill rate following a small break LOCA and because analysis of hypothetical severe accidents with the current flooding models in reactor safety codes shows that these models represent the largest uncertainty in analysis of steam generator tube creep rupture. During a hypothetical station blackout without auxiliary feedwater recovery, should the hot leg become voided, the pressurizer liquid will drain to the hot leg and flooding may occur in the surge line. The flooding model heavily influences the pressurizer emptying rate and the potential for surge line structural failure due to overheating and creep rupture. The air-water test results in vertical tubes are presented in this paper along with a semi-empirical correlation for the onset of flooding. The unique aspects of the study include careful experimentation on large-diameter tubes and an integrated program in which air-water testing provides benchmark knowledge and visualization data from which to conduct steam-water testing.

  14. Pesticide uptake in potatoes: model and field experiments.

    PubMed

    Juraske, Ronnie; Vivas, Carmen S Mosquera; Velásquez, Alexander Erazo; Santos, Glenda García; Moreno, Mónica B Berdugo; Gomez, Jaime Diaz; Binder, Claudia R; Hellweg, Stefanie; Dallos, Jairo A Guerrero

    2011-01-15

    A dynamic model for uptake of pesticides in potatoes is presented and evaluated with measurements performed within a field trial in the region of Boyacá, Colombia. The model takes into account the time between pesticide applications and harvest, the time between harvest and consumption, the amount of spray deposition on soil surface, mobility and degradation of pesticide in soil, diffusive uptake and persistence due to crop growth and metabolism in plant material, and loss due to food processing. Food processing steps included were cleaning, washing, storing, and cooking. Pesticide concentrations were measured periodically in soil and potato samples from the beginning of tuber formation until harvest. The model was able to predict the magnitude and temporal profile of the experimentally derived pesticide concentrations well, with all measurements falling within the 90% confidence interval. The fraction of chlorpyrifos applied on the field during plant cultivation that eventually is ingested by the consumer is on average 10(-4)-10(-7), depending on the time between pesticide application and ingestion and the processing step considered. PMID:21141816

  15. Comparison Between Keyhole Weld Model and Laser Welding Experiments

    SciTech Connect

    Wood, B C; Palmer, T A; Elmer, J W

    2002-09-23

    A series of laser welds were performed using a high-power diode-pumped continuous-wave Nd:YAG laser welder. In a previous study, the experimental results of those welds were examined, and the effects that changes in incident power and various welding parameters had on weld geometry were investigated. In this report, the fusion zones of the laser welds are compared with those predicted from a laser keyhole weld simulation model for stainless steels (304L and 21-6-9), vanadium, and tantalum. The calculated keyhole depths for the vanadium and 304L stainless steel samples fit the experimental data to within acceptable error, demonstrating the predictive power of numerical simulation for welds in these two materials. Calculations for the tantalum and 21-6-9 stainless steel were a poorer match to the experimental values. Accuracy in materials properties proved extremely important in predicting weld behavior, as minor changes in certain properties had a significant effect on calculated keyhole depth. For each of the materials tested, the correlation between simulated and experimental keyhole depths deviated as the laser power was increased. Using the model as a simulation tool, we conclude that the optical absorptivity of the material is the most influential factor in determining the keyhole depth. Future work will be performed to further investigate these effects and to develop a better match between the model and the experimental results for 21-6-9 stainless steel and tantalum.

  16. Numerical experiments with model monophyletic and paraphyletic taxa

    NASA Technical Reports Server (NTRS)

    Sepkoski, J. J. Jr; Kendrick, D. C.; Sepkoski JJ, J. r. (Principal Investigator)

    1993-01-01

    The problem of how accurately paraphyletic taxa versus monophyletic (i.e., holophyletic) groups (clades) capture underlying species patterns of diversity and extinction is explored with Monte Carlo simulations. Phylogenies are modeled as stochastic trees. Paraphyletic taxa are defined in an arbitrary manner by randomly choosing progenitors and clustering all descendants not belonging to other taxa. These taxa are then examined to determine which are clades, and the remaining paraphyletic groups are dissected to discover monophyletic subgroups. Comparisons of diversity patterns and extinction rates between modeled taxa and lineages indicate that paraphyletic groups can adequately capture lineage information under a variety of conditions of diversification and mass extinction. This suggests that these groups constitute more than mere "taxonomic noise" in this context. But, strictly monophyletic groups perform somewhat better, especially with regard to mass extinctions. However, when low levels of paleontologic sampling are simulated, the veracity of clades deteriorates, especially with respect to diversity, and modeled paraphyletic taxa often capture more information about underlying lineages. Thus, for studies of diversity and taxic evolution in the fossil record, traditional paleontologic genera and families need not be rejected in favor of cladistically-defined taxa.

  17. Anisotropic magnetoresistivity in structured elastomer composites: modelling and experiments.

    PubMed

    Mietta, José Luis; Tamborenea, Pablo I; Martin Negri, R

    2016-08-14

    A constitutive model for the anisotropic magnetoresistivity in structured elastomer composites (SECs) is proposed. The SECs considered here are oriented pseudo-chains of conductive-magnetic inorganic materials inside an elastomer organic matrix. The pseudo-chains are formed by fillers which are simultaneously conductive and magnetic dispersed in the polymer before curing or solvent evaporation. The SEC is then prepared in the presence of a uniform magnetic field, referred to as Hcuring. This procedure generates the pseudo-chains, which are preferentially aligned in the direction of Hcuring. Electrical conduction is present in that direction only. The constitutive model for the magnetoresistance considers the magnetic pressure, Pmag, induced on the pseudo-chains by an external magnetic field, H, applied in the direction of the pseudo-chains. The relative changes in conductivity as a function of H are calculated by evaluating the relative increase of the electron tunnelling probability with Pmag, a magneto-elastic coupling which produces an increase of conductivity with magnetization. The model is used to adjust experimental results of magnetoresistance in a specific SEC where the polymer is polydimethylsiloxane, PDMS, and fillers are microparticles of magnetite-silver (referred to as Fe3O4[Ag]). Simulations of the expected response for other materials in both superparamagnetic and blocked magnetic states are presented, showing the influence of the Young's modulus of the matrix and filler's saturation magnetization. PMID:27418417

  18. Grip Forces During Object Manipulation: Experiment, Mathematical Model & Validation

    PubMed Central

    Slota, Gregory P.; Latash, Mark L.; Zatsiorsky, Vladimir M.

    2011-01-01

    When people transport handheld objects, they change the grip force with the object movement. Circular movement patterns were tested within three planes at two different rates (1.0, 1.5 Hz), and two diameters (20, 40 cm). Subjects performed the task reasonably well, matching frequencies and dynamic ranges of accelerations within expectations. A mathematical model was designed to predict the applied normal forces from kinematic data. The model is based on two hypotheses: (a) the grip force changes during movements along complex trajectories can be represented as the sum of effects of two basic commands associated with the parallel and orthogonal manipulation, respectively; (b) different central commands are sent to the thumb and virtual finger (Vf- four fingers combined). The model predicted the actual normal forces with a total variance accounted for of better than 98%. The effects of the two components of acceleration—along the normal axis and the resultant acceleration within the shear plane—on the digit normal forces are additive. PMID:21735245

  19. Mathematical Modeling of Eukaryotic Cell Migration: Insights Beyond Experiments

    PubMed Central

    Danuser, Gaudenz; Allard, Jun; Mogilner, Alex

    2014-01-01

    A migrating cell is a molecular machine made of tens of thousands of short-lived and interacting parts. Understanding migration means understanding the self-organization of these parts into a system of functional units. This task is one of tackling complexity: First, the system integrates numerous chemical and mechanical component processes. Second, these processes are connected in feedback interactions and over a large range of spatial and temporal scales. Third, many processes are stochastic, which leads to heterogeneous migration behaviors. Early on in the research of cell migration it became evident that this complexity exceeds human intuition. Thus, the cell migration community has led the charge to build mathematical models that could integrate the diverse experimental observations and measurements in consistent frameworks, first in conceptual and more recently in molecularly explicit models. The main goal of this review is to sift through a series of important conceptual and explicit mathematical models of cell migration and to evaluate their contribution to the field in their ability to integrate critical experimental data. PMID:23909278

  20. Preservation of fresh noodles by irradiation

    NASA Astrophysics Data System (ADS)

    Jianming, Cai

    1998-06-01

    At the present paper, it is studied to preserve fresh noodles by irradiation. The noodles which were irradiated by 10 kGy of 60Co-γ rays and stored at room temperature (18-24°C). The appearance of the noodles was observed, the bacteria in the noodles were examines, and the acidity of the noodles was measured during 10 days after irradiation. The results showed that the number of bacteria and the extent of acidification of the noodles were in inverse proportion to radiation dose. When the absorbed dose was less than 8 kGy, the residual bacteria in the noodles could proliferate massively in several days and acidified the noodles. The pH of these noodles decreased from 6.2 to 5.0 or less and the noodles turned into sticky during storage. When the absorbed dose reached 8-10 kGy, most of bacteria were killed and the acidity of the noodles kept about pH 6.0. The appearance of the noodles looks fresh within 10 days after irradiation. They smelled as good as fresh ones.