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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. 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

  4. 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.

  5. 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…

  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. Desorption isotherms for fresh beef: an experimental and modeling approach.

    PubMed

    Ahmat, Tom; Bruneau, Denis; Kuitche, Alexis; Waste Aregba, Aworou

    2014-04-01

    Desorption isotherms for fresh beef were determined at 30, 40 and 50°C by the static gravimetric method. The resulting isotherms exhibited a type II sigmoid shape. The BET, GAB and Halsey models were used to fit these experimental data. The GAB model was most accurate for all temperatures and all levels of water activity, followed by the BET and Halsey models. The temperature dependence of GAB constants was estimated. The isosteric heat of desorption and its evolution in relation to moisture content were calculated using Clausius-Clapeyron equations. The monolayer moisture content was determined using the GAB model: it decreased as the temperature increased. The density of bound water, the number of adsorption sites, the sorption surface area and the percentage of bound water were calculated using the Caurie equation: all these quantities decreased as the temperature increased. The Kelvin and Halsey equations were used for calculation of pore size, which increases with an increase in moisture levels and sorption temperature.

  8. Tissue modeling following implant placement in fresh extraction sockets.

    PubMed

    Araújo, Mauricio G; Sukekava, Flavia; Wennström, Jan L; Lindhe, Jan

    2006-12-01

    To study whether osseointegration once established following implant placement in a fresh extraction socket may be lost as a result of tissue modeling. Seven beagle dogs were used. The third and fourth premolars in both quadrants of the mandible were used as experimental teeth. Buccal and lingual full-thickness flaps were elevated and distal roots were removed. Implants were installed in the fresh extraction socket. Semi-submerged healing of the implant sites was allowed. In five dogs, the experimental procedure was first performed in the right side of the mandible and 2 months later in the left mandible. These five animals were sacrificed 1 month after the final implant installation. In two dogs, the premolar sites on both sides of the mandible were treated in one surgical session and biopsies were obtained immediately after implant placement. All biopsies were processed for ground sectioning and stained. The void that existed between the implant and the socket walls at surgery was filled at 4 weeks with woven bone that made contact with the SLA surface. In this interval, (i) the buccal and lingual bone walls underwent marked surface resorption and (ii) the height of the thin buccal hard tissue wall was reduced. The process of healing continued, and the buccal bone crest shifted further in the apical direction. After 12 weeks, the buccal crest was located>2 mm apical of the marginal border of the SLA surface. The bone-to-implant contact that was established during the early phase of socket healing following implant installation was in part lost when the buccal bone wall underwent continued resorption.

  9. Fresh Start: A Model for Success and Sustainable Change

    ERIC Educational Resources Information Center

    Matthews, Susan; Kinchington, Francia

    2006-01-01

    This article examines the rationale and debate of the "Fresh Start" schools policy introduced by the New Labour Government in 1997 as a vehicle for improvement in schools that historically had been classified as "failing". Underpinning the policy is the assumption that Fresh Start can act as a catalytic agent of positive change…

  10. Characterization and Application of Antilisterial Enterocins on Model Fresh Cheese.

    PubMed

    Ribeiro, Susana C; Ross, R Paul; Stanton, Catherine; Silva, Célia C G

    2017-08-01

    Enterococcus faecalis strains isolated from an artisanal cheese were selected based on enterocin production against Listeria monocytogenes. The strains formed biofilms and presented high hydrophobic character and good autoaggregation and coaggregation capacity with L. monocytogenes. Strains L3A21M3 and L3B1K3 presented high survival under gastrointestinal conditions, were able to adhere to human intestinal cells (Caco-2 and HT-29), and blocked the adhesion and invasion of L. monocytogenes. The antilisterial activity of enterocins was not affected by pH (2 to 12), heating (100°C), and chemical and surfactant agents. However, strains L3A21M3 and L3A21M8 produced thermolabile enterocins, which were also sensible to extreme pH values. Enterocins exhibited a bacteriostatic mode of action against L. monocytogenes, and maximum production was observed during the stationary phase. Common enterocin structural genes were not detected by PCR amplification with specific primers, although an exhaustive screening was not performed. The enterocin produced by the L3B1K3 strain was purified and applied to model cheeses contaminated with L. monocytogenes. This enterocin reduced survival of L. monocytogenes on fresh cheeses in a dose-dependent manner. The highest dose tested (2,048 arbitrary units per g of cheese) was effective in reducing the pathogen counts to undetectable values throughout storage (6 to 72 h). These results suggest that these strains have great potential to be used as biopreservatives in the food industry and also as probiotics, with the potential to prevent L. monocytogenes gastrointestinal infection.

  11. 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.

  12. The US military experience with fresh whole blood during the conflicts in Iraq and Afghanistan.

    PubMed

    Chandler, Mark H; Roberts, Matthew; Sawyer, Mike; Myers, Greg

    2012-09-01

    Since its introduction in the early part of the last century, fresh whole blood (FWB) has been used by the US military as a battlefield expedient resuscitation method, even after the development of component therapy in the 1960s. In the recent conflicts in Iraq and Afghanistan, FWB was used once more, often collected in the setting of a walking blood bank (WBB). Considerable research and opinion from military circles has cited these experiences and sparked renewed interest in FWB as an effective resuscitation tool in the setting of trauma. Despite efforts by the US military to improve the effectiveness and safety of FWB through a series of widely published guidelines, transfusion transmitted infections (TTI) remain a vexing challenge. These experiences in Iraq and Afghanistan will help inform a larger discussion regarding the reintroduction of FWB in civilian trauma resuscitation.

  13. 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.

  14. A predictive bone drilling force model for haptic rendering with experimental validation using fresh cadaveric bone.

    PubMed

    Lin, Yanping; Chen, Huajiang; Yu, Dedong; Zhang, Ying; Yuan, Wen

    2017-01-01

    Bone drilling simulators with virtual and haptic feedback provide a safe, cost-effective and repeatable alternative to traditional surgical training methods. To develop such a simulator, accurate haptic rendering based on a force model is required to feedback bone drilling forces based on user input. Current predictive bone drilling force models based on bovine bones with various drilling conditions and parameters are not representative of the bone drilling process in bone surgery. The objective of this study was to provide a bone drilling force model for haptic rendering based on calibration and validation experiments in fresh cadaveric bones with different bone densities. Using a commonly used drill bit geometry (2 mm diameter), feed rates (20-60 mm/min) and spindle speeds (4000-6000 rpm) in orthognathic surgeries, the bone drilling forces of specimens from two groups were measured and the calibration coefficients of the specific normal and frictional pressures were determined. The comparison of the predicted forces and the measured forces from validation experiments with a large range of feed rates and spindle speeds demonstrates that the proposed bone drilling forces can predict the trends and average forces well. The presented bone drilling force model can be used for haptic rendering in surgical simulators.

  15. A Pulsatile Fresh Frozen Human Cadaver Circulation Model for Endovascular Training: A Trial of Face Validity.

    PubMed

    Nesbitt, Craig; Tingle, Samuel James; Williams, Robin; McCaslin, James; Searle, Roger; Mafeld, Sebastian; Stansby, Gerard

    2017-09-06

    The authors have published their design of a pulsatile fresh frozen human cadaver circulation model (PHCM) for endovascular training the face validity of the PHCM for training endovascular practitioners was subsequently assessed. Twelve endovascular clinicians performed the same 2 procedures (catheterization of the left renal artery and left subclavian artery) on PHCM and Simbionix angiomentor virtual reality simulator (SVR). They were randomized to begin on either the PHCM or SVR. A pretrial questionnaire determined participants' endovascular experience. After training, participants rated statements relating to their experience on a numerical scale from 1 to 5, with 1 representing the strongest agreement with the statement. When participants were asked to compare the realism of training modalities with live patients, PHCM scored significantly higher than SVR on statements regarding "realism of vascular access" (P = 0.002), "guide-wire manipulation" (P = 0.001), and "vessel catheterization" (P = 0.004). Candidates again favored PHCM as "a valuable learning exercise" (P = 0.016) and strongly favored PHCM as a "useful training model" compared to SVR (P = 0.004). This is the first published trial in world literature to assess the validity of a PHCM for training endovascular practitioners. The PHCM demonstrates good face validity when compared to both real patients and the SVR model and holds exciting potential. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. 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.

  17. 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.

  18. Modelling metabolic CO₂ evolution--a fresh perspective on respiration.

    PubMed

    Sweetlove, Lee J; Williams, Thomas C R; Cheung, C Y Maurice; Ratcliffe, R George

    2013-09-01

    Respiration is a major contributor to net exchange of CO₂ between plants and the atmosphere and thus an important aspect of the vegetation component of global climate change models. However, a mechanistic model of respiration is lacking, and so here we explore the potential for flux balance analysis (FBA) to predict cellular CO₂ evolution rates. Metabolic flux analysis reveals that respiration is not always the dominant source of CO₂, and that metabolic processes such as the oxidative pentose phosphate pathway (OPPP) and lipid synthesis can be quantitatively important. Moreover, there is considerable variation in the metabolic origin of evolved CO₂ between tissues, species and conditions. Comparison of FBA-predicted CO₂ evolution profiles with those determined from flux measurements reveals that FBA is able to predict the metabolic origin of evolved CO₂ in different tissues/species and under different conditions. However, FBA is poor at predicting flux through certain metabolic processes such as the OPPP and we identify the way in which maintenance costs are accounted for as a major area of improvement for future FBA studies. We conclude that FBA, in its standard form, can be used to predict CO₂ evolution in a range of plant tissues and in response to environment. © 2013 John Wiley & Sons Ltd.

  19. 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

  20. 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.

  1. 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.

  2. Fresh water balance of the Gulf Stream system in a regional model study

    NASA Astrophysics Data System (ADS)

    Gerdes, R.; Biastoch, A.; Redler, R.

    We investigate the dependence of surface fresh water fluxes in the Gulf Stream and North Atlantic Current (NAC) area on the position of the stream axis which is not well represented in most ocean models. To correct this shortcoming, strong unrealistic surface fresh water fluxes have to be applied that lead to an incorrect salt balance of the current system. The unrealistic surface fluxes required by the oceanic component may force flux adjustments and may cause fictitious long-term variability in coupled climate models. To identify the important points in the correct representation of the salt balance of the Gulf Stream a regional model of the northwestern part of the subtropical gyre has been set up. Sensitivity studies are made where the westward flow north of the Gulf Stream and its properties are varied. Increasing westward volume transport leads to a southward migration of the Gulf Stream separation point along the American coast. The salinity of the inflow is essential for realistic surface fresh water fluxes and the water mass distribution. The subpolar-subtropical connection is important in two ways: The deep dense flow from the deep water mass formation areas sets up the cyclonic circulation cell north of the Gulf Stream. The surface and mid depth flow of fresh water collected at high northern latitudes is mixed into the Gulf Stream and compensates for the net evaporation at the surface.

  3. Measured and modeled humidification factors of fresh smoke particles from biomass burning: role of inorganic constituents

    NASA Astrophysics Data System (ADS)

    Hand, J. L.; Day, D. E.; McMeeking, G. M.; Levin, E. J. T.; Carrico, C. M.; Kreidenweis, S. M.; Malm, W. C.; Laskin, A.; Desyaterik, Y.

    2010-02-01

    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.

  4. Measured and modeled humidification factors of fresh smoke particles from biomass burning: role of inorganic constituents

    NASA Astrophysics Data System (ADS)

    Hand, J. L.; Day, D. E.; McMeeking, G. M.; Levin, E. J. T.; Carrico, C. M.; Kreidenweis, S. M.; Malm, W. C.; Laskin, A.; Desyaterik, Y.

    2010-07-01

    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 from the west and southeast United States showed large variability in the humidification factor (f(RH)=bsp(RH)/bsp(dry)). Values of f(RH) at RH=80-85% ranged from 0.99 to 1.81 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 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 80-85% 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.

  5. 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.

  6. 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

  7. Construct Validity of Fresh Frozen Human Cadaver as a Training Model in Minimal Access Surgery

    PubMed Central

    Macafee, David; Pranesh, Nagarajan; Horgan, Alan F.

    2012-01-01

    Background: The construct validity of fresh human cadaver as a training tool has not been established previously. The aims of this study were to investigate the construct validity of fresh frozen human cadaver as a method of training in minimal access surgery and determine if novices can be rapidly trained using this model to a safe level of performance. Methods: Junior surgical trainees, novices (<3 laparoscopic procedure performed) in laparoscopic surgery, performed 10 repetitions of a set of structured laparoscopic tasks on fresh frozen cadavers. Expert laparoscopists (>100 laparoscopic procedures) performed 3 repetitions of identical tasks. Performances were scored using a validated, objective Global Operative Assessment of Laparoscopic Skills scale. Scores for 3 consecutive repetitions were compared between experts and novices to determine construct validity. Furthermore, to determine if the novices reached a safe level, a trimmed mean of the experts score was used to define a benchmark. Mann-Whitney U test was used for construct validity analysis and 1-sample t test to compare performances of the novice group with the benchmark safe score. Results: Ten novices and 2 experts were recruited. Four out of 5 tasks (nondominant to dominant hand transfer; simulated appendicectomy; intracorporeal and extracorporeal knot tying) showed construct validity. Novices’ scores became comparable to benchmark scores between the eighth and tenth repetition. Conclusion: Minimal access surgical training using fresh frozen human cadavers appears to have construct validity. The laparoscopic skills of novices can be accelerated through to a safe level within 8 to 10 repetitions. PMID:23318058

  8. 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…

  9. 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

  10. The novel laparoscopic training 3D model in urology with surgical anatomic remarks: Fresh-frozen cadaveric tissue

    PubMed Central

    Huri, Emre; Ezer, Mehmet; Chan, Eddie

    2016-01-01

    Laparoscopic surgery is routinely used to treat many urological conditions and it is the gold standard treatment option for many surgeries such as radical nephrectomy. Due to the difficulty of learning, laparoscopic training should start outside the operating room. Although it is a very different model of laparoscopic training; the aim of this review is to show the value of human cadaveric model for laparoscopic training and present our experience in this area. Fresh frozen cadaveric model in laparoscopic training, dry lab, cadaveric model, animal models and computer based simulators are the most commonly used models for laparoscopic training. Cadaveric models mimic the live setting better than animal models. Also, it is the best way in demonstrating important anatomic landmarks like prostate, bladder, and pelvic lymph nodes templates. However, cadaveric training is expensive, and should be used by multiple disciplines for higher efficiency. The laparosopic cadaveric training starts with didactic lectures with introduction of pelvic surgical anatomy. It is followed by hands-on dissection. A typical pelvic dissection part can be completed in 6 hours. Surgical robot and some laparoscopy platforms are equipped with 3-D vision. In recent years, we have use the stereoscopic laparoscopy system for training purposes to show exact anatomic landmarks. Cadavers are removed from their containers 3 to 5 days prior to training session to allow enough time for thawing. Intracorporeal suturing is an important part of laparoscopic training. We believe that suturing must be practiced in the dry lab, which is significantly cheaper than cadaveric models. Cadaveric training model should focus on the anatomic dissection instead. In conclusion, fresh-frozen cadaveric sample is one of the best 3D simulation models for laparoscopic training purposes. Major aim of cadaveric training is not only mimicking the surgical technique but also teaching true anatomy. Lack of availability and higher

  11. The novel laparoscopic training 3D model in urology with surgical anatomic remarks: Fresh-frozen cadaveric tissue.

    PubMed

    Huri, Emre; Ezer, Mehmet; Chan, Eddie

    2016-12-01

    Laparoscopic surgery is routinely used to treat many urological conditions and it is the gold standard treatment option for many surgeries such as radical nephrectomy. Due to the difficulty of learning, laparoscopic training should start outside the operating room. Although it is a very different model of laparoscopic training; the aim of this review is to show the value of human cadaveric model for laparoscopic training and present our experience in this area. Fresh frozen cadaveric model in laparoscopic training, dry lab, cadaveric model, animal models and computer based simulators are the most commonly used models for laparoscopic training. Cadaveric models mimic the live setting better than animal models. Also, it is the best way in demonstrating important anatomic landmarks like prostate, bladder, and pelvic lymph nodes templates. However, cadaveric training is expensive, and should be used by multiple disciplines for higher efficiency. The laparosopic cadaveric training starts with didactic lectures with introduction of pelvic surgical anatomy. It is followed by hands-on dissection. A typical pelvic dissection part can be completed in 6 hours. Surgical robot and some laparoscopy platforms are equipped with 3-D vision. In recent years, we have use the stereoscopic laparoscopy system for training purposes to show exact anatomic landmarks. Cadavers are removed from their containers 3 to 5 days prior to training session to allow enough time for thawing. Intracorporeal suturing is an important part of laparoscopic training. We believe that suturing must be practiced in the dry lab, which is significantly cheaper than cadaveric models. Cadaveric training model should focus on the anatomic dissection instead. In conclusion, fresh-frozen cadaveric sample is one of the best 3D simulation models for laparoscopic training purposes. Major aim of cadaveric training is not only mimicking the surgical technique but also teaching true anatomy. Lack of availability and higher

  12. MODELING ASSUMPTIONS FOR THE ADVANCED TEST REACTOR FRESH FUEL SHIPPING CONTAINER

    SciTech Connect

    Rick J. Migliore

    2009-09-01

    The Advanced Test Reactor Fresh Fuel Shipping Container (ATR FFSC) is currently licensed per 10 CFR 71 to transport a fresh fuel element for either the Advanced Test Reactor, the University of Missouri Research Reactor (MURR), or the Massachusetts Institute of Technology Research Reactor (MITR-II). During the licensing process, the Nuclear Regulatory Commission (NRC) raised a number of issues relating to the criticality analysis, namely (1) lack of a tolerance study on the fuel and packaging, (2) moderation conditions during normal conditions of transport (NCT), (3) treatment of minor hydrogenous packaging materials, and (4) treatment of potential fuel damage under hypothetical accident conditions (HAC). These concerns were adequately addressed by modifying the criticality analysis. A tolerance study was added for both the packaging and fuel elements, full-moderation was included in the NCT models, minor hydrogenous packaging materials were included, and fuel element damage was considered for the MURR and MITR-II fuel types.

  13. Translational intracerebral hemorrhage: a need for transparent descriptions of fresh tissue sampling and preclinical model quality.

    PubMed

    Chang, Che-Feng; Cai, Li; Wang, Jian

    2015-10-01

    For years, strategies have been proposed to improve translational success in stroke research by improving the quality of animal studies. However, articles that report preclinical intracerebral hemorrhage (ICH) studies continue to lack adequate qualitative and quantitative descriptions of fresh brain tissue collection. They also tend to lack transparency about animal model quality. We conducted a systematic review of 82 ICH research articles to determine the level of detail reported for brain tissue collection. We found that only 24 (29 %) reported the volume, weight, or thickness of tissue collected and a specific description of the anatomical location. Thus, up to 71 % of preclinical ICH research articles did not properly define how fresh specimens were collected for biochemical measurements. Such omissions may impede reproducibility of results between laboratories. Although existing criteria have improved the quality of preclinical stroke studies, ICH researchers need to identify specific guidelines and strategies to avoid pitfalls, minimize bias, and increase reproducibility in this field.

  14. Translational Intracerebral Hemorrhage: A Need for Transparent Descriptions of Fresh Tissue Sampling and Preclinical Model Quality

    PubMed Central

    Chang, Che-Feng; Cai, Li; Wang, Jian

    2015-01-01

    For years, strategies have been proposed to improve translational success in stroke research by improving the quality of animal studies. However, articles that report preclinical intracerebral hemorrhage (ICH) studies continue to lack adequate qualitative and quantitative descriptions of fresh brain tissue collection. They also tend to lack transparency about animal model quality. We conducted a systematic review of 82 ICH research articles to determine the level of detail reported for brain tissue collection. We found that only 24 (29%) reported the volume, weight, or thickness of tissue collected and a specific description of the anatomical location. Thus, up to 71% of preclinical ICH research articles did not properly define how fresh specimens were collected for biochemical measurements. Such omissions may impede reproducibility of results between laboratories. Although existing criteria have improved the quality of preclinical stroke studies, ICH researchers need to identify specific guidelines and strategies to avoid pitfalls, minimize bias, and increase reproducibility in this field. PMID:25907620

  15. Modelling the growth of Listeria monocytogenes in fresh green coconut (Cocos nucifera L.) water.

    PubMed

    Walter, Eduardo H M; Kabuki, Dirce Y; Esper, Luciana M R; Sant'Ana, Anderson S; Kuaye, Arnaldo Y

    2009-09-01

    The behaviour of Listeria monocytogenes in the fresh coconut water stored at 4 degrees C, 10 degrees C and 35 degrees C was studied. The coconut water was aseptically extracted from green coconuts (Cocos nucifera L.) and samples were inoculated in triplicate with a mixture of 5 strains of L. monocytogenes with a mean population of approximately 3 log(10) CFU/mL. The kinetic parameters of the bacteria were estimated from the Baranyi model, and compared with predictions of the Pathogen Modelling Program so as to predict its behaviour in the beverage. The results demonstrated that fresh green coconut water was a beverage propitious for the survival and growth of L. monocytogenes and that refrigeration at 10 degrees C or 4 degrees C retarded, but did not inhibit, growth of this bacterium. Temperature abuse at 35 degrees C considerably reduced the lagtimes. The study shows that L. monocytogenes growth in fresh green coconut water is controlled for several days by storage at low temperature, mainly at 4 degrees C. Thus, for risk population this product should only be drunk directly from the coconut or despite the sensorial alterations should be consumed pasteurized.

  16. [Proposed difficult airway teaching methodology. Presentation of an interactive fresh frozen cadaver model].

    PubMed

    Catalá Bauset, J C; de Andres Ibañez, J A; Valverde Navarro, A; Martinez Soriano, F

    2014-04-01

    The aim of this paper is to present a methodology based on the use of fresh-frozen cadavers for training in the management of the airway, and to evaluate the degree of satisfaction among learning physicians. About 6 fresh-frozen cadavers and 14 workstations were prepared where participants were trained in the different skills needed for airway management. The details of preparation of the cadavers are described. The level of satisfaction of the participant was determined using a Likert rating scale of 5 points, at each of the 14 stations, as well as the overall assessment and clinical usefulness of the course. The mean overall evaluation of the course and its usefulness was 4.75 and 4.9, out of 5, respectively. All parts of the course were rated above 4 out of 5. The high level of satisfaction of the course remained homogeneous in the 2 editions analysed. The overall satisfaction of the course was not finally and uniquely determined by any of its particular parts. The fresh cadaver model for training physicians in techniques of airway management is a proposal satisfactory to the participant, and with a realism that approaches the live patient. Copyright © 2013 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Published by Elsevier España. All rights reserved.

  17. 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

  18. 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

  19. 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

  20. Shelf-life prediction models for ready-to-eat fresh cut salads: Testing in real cold chain.

    PubMed

    Tsironi, Theofania; Dermesonlouoglou, Efimia; Giannoglou, Marianna; Gogou, Eleni; Katsaros, George; Taoukis, Petros

    2017-01-02

    The aim of the study was to develop and test the applicability of predictive models for shelf-life estimation of ready-to-eat (RTE) fresh cut salads in realistic distribution temperature conditions in the food supply chain. A systematic kinetic study of quality loss of RTE mixed salad (lollo rosso lettuce-40%, lollo verde lettuce-45%, rocket-15%) packed under modified atmospheres (3% O2, 10% CO2, 87% N2) was conducted. Microbial population (total viable count, Pseudomonas spp., lactic acid bacteria), vitamin C, colour and texture were the measured quality parameters. Kinetic models for these indices were developed to determine the quality loss and calculate product remaining shelf-life (SLR). Storage experiments were conducted at isothermal (2.5-15°C) and non-isothermal temperature conditions (Teff=7.8°C defined as the constant temperature that results in the same quality value as the variable temperature distribution) for validation purposes. Pseudomonas dominated spoilage, followed by browning and chemical changes. The end of shelf-life correlated with a Pseudomonas spp. level of 8 log(cfu/g), and 20% loss of the initial vitamin C content. The effect of temperature on these quality parameters was expressed by the Arrhenius equation; activation energy (Ea) value was 69.1 and 122.6kJ/mol for Pseudomonas spp. growth and vitamin C loss rates, respectively. Shelf-life prediction models were also validated in real cold chain conditions (including the stages of transport to and storage at retail distribution center, transport to and display at 7 retail stores, transport to and storage in domestic refrigerators). The quality level and SLR estimated after 2-3days of domestic storage (time of consumption) ranged between 1 and 8days at 4°C and was predicted within satisfactory statistical error by the kinetic models. Teff in the cold chain ranged between 3.7 and 8.3°C. Using the validated models, SLR of RTE fresh cut salad can be estimated at any point of the cold chain

  1. Coagulation parameters as a guide for fresh frozen plasma transfusion practice: A tertiary hospital experience.

    PubMed

    Wan Haslindawani, W M; Wan Zaidah, A

    2010-01-01

    The appropriate use of blood and blood products means the transfusion of safe blood products only to treat a condition leading to significant morbidity or mortality, which cannot be prevented or managed effectively by other means. The safety and effectiveness of transfusion depend on the appropriate clinical use of blood and blood products. This study was conducted to review the practice of fresh frozen plasma usage (FFP) for transfusion, based on the coagulation profile, requested by various departments in the Hospital Universiti Sains Malaysia (HUSM). A retrospective review of blood bank records and coagulation profile results of the patients given FFP from October to December 2006, in Hospital USM was undertaken. The criteria set by the College of American Pathologists in 1994, were used as the guidelines. One thousand six hundred and ninety-eight units of FFP were used during this study period. Only 806 (47.47%) FFP units were deemed appropriate. 20.38% were based on studies without any coagulation tests prior to transfusion and 21.13% were transfused for mild prolongation of coagulation test results. About 6.41% requested FFP in the setting of normal coagulation results. Our results showed that a significant proportion of the FFP transfusion was not guided by the coagulation profile. We recommend that a continuous education on FFP transfusion may help to guide the appropriate request for FFP.

  2. Genomic characterization of explant tumorgraft models derived from fresh patient tumor tissue

    PubMed Central

    2012-01-01

    Background There is resurgence within drug and biomarker development communities for the use of primary tumorgraft models as improved predictors of patient tumor response to novel therapeutic strategies. Despite perceived advantages over cell line derived xenograft models, there is limited data comparing the genotype and phenotype of tumorgrafts to the donor patient tumor, limiting the determination of molecular relevance of the tumorgraft model. This report directly compares the genomic characteristics of patient tumors and the derived tumorgraft models, including gene expression, and oncogenic mutation status. Methods Fresh tumor tissues from 182 cancer patients were implanted subcutaneously into immune-compromised mice for the development of primary patient tumorgraft models. Histological assessment was performed on both patient tumors and the resulting tumorgraft models. Somatic mutations in key oncogenes and gene expression levels of resulting tumorgrafts were compared to the matched patient tumors using the OncoCarta (Sequenom, San Diego, CA) and human gene microarray (Affymetrix, Santa Clara, CA) platforms respectively. The genomic stability of the established tumorgrafts was assessed across serial in vivo generations in a representative subset of models. The genomes of patient tumors that formed tumorgrafts were compared to those that did not to identify the possible molecular basis to successful engraftment or rejection. Results Fresh tumor tissues from 182 cancer patients were implanted into immune-compromised mice with forty-nine tumorgraft models that have been successfully established, exhibiting strong histological and genomic fidelity to the originating patient tumors. Comparison of the transcriptomes and oncogenic mutations between the tumorgrafts and the matched patient tumors were found to be stable across four tumorgraft generations. Not only did the various tumors retain the differentiation pattern, but supporting stromal elements were preserved

  3. Establishment of a 3D cell culture model of primary bovine mammary epithelial cells extracted from fresh milk.

    PubMed

    Hillreiner, Maria; Müller, Nadine I; Koch, Heiner M; Schmautz, Christiane; Küster, Bernhard; Pfaffl, Michael W; Kliem, Heike

    2017-06-22

    For the investigation of molecular processes underlying diseases of the bovine mammary gland, primary bovine mammary epithelial cells (pbMEC) are used. They are known to contribute to the innate immune system of the bovine mammary gland. The functionality of pbMEC depends on the maintenance of in vivo characteristics. So far, the optimization of pbMEC culture conditions was intended in a variety of experiments. For this purpose, most of the studies used stable cell lines or primary cells obtained from udder biopsies of slaughtered animals. By contrast, within our study, pbMEC of healthy and first lactating Brown Swiss cows were non-invasively isolated from fresh milk. The non-invasively isolated pbMEC were cultivated on the extracellular matrix-like scaffold Matrigel®. Further, they were challenged with different compositions of proliferation media, containing lactogenic hormones and/or the essential amino acid L-lysine. Changes in expression levels of genes coding for milk proteins and for components of the janus kinase/signal transducers and activators of transcription (JAK-STAT) and mTOR pathways were analyzed by RT-qPCR. The secreted proteins were analyzed by LC-MS/MS measurements. We showed for the first time the establishment of a physiologically functional 3D cell culture model of pbMEC isolated from fresh milk. This represents a primary cell culture model system, based on non-invasive cell collection, that can be used to unravel physiological processes in an unbiased manner.

  4. 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

  5. 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

  6. 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).

  7. 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.

  8. Geochemistry of trace metals in a fresh water sediment: field results and diagenetic modeling.

    PubMed

    Canavan, R W; Van Cappellen, P; Zwolsman, J J G; van den Berg, G A; Slomp, C P

    2007-08-01

    Concentrations of Fe, Mn, Cd, Co, Ni, Pb, and Zn were determined in pore water and sediment of a coastal fresh water lake (Haringvliet Lake, The Netherlands). Elevated sediment trace metal concentrations reflect anthropogenic inputs from the Rhine and Meuse Rivers. Pore water and sediment analyses, together with thermodynamic calculations, indicate a shift in trace metal speciation from oxide-bound to sulfide-bound over the upper 20 cm of the sediment. Concentrations of reducible Fe and Mn decline with increasing depth, but do not reach zero values at 20 cm depth. The reducible phases are relatively more important for the binding of Co, Ni, and Zn than for Pb and Cd. Pore waters exhibit supersaturation with respect to Zn, Pb, Co, and Cd monosulfides, while significant fractions of Ni and Co are bound to pyrite. A multi-component, diagenetic model developed for organic matter degradation was expanded to include Zn and Ni dynamics. Pore water transport of trace metals is primarily diffusive, with a lesser contribution of bioirrigation. Reactions affecting trace metal mobility near the sediment-water interface, especially sulfide oxidation and sorption to newly formed oxides, strongly influence the modeled estimates of the diffusive effluxes to the overlying water. Model results imply less efficient sediment retention of Ni than Zn. Sensitivity analyses show that increased bioturbation and sulfate availability, which are expected upon restoration of estuarine conditions in the lake, should increase the sulfide bound fractions of Zn and Ni in the sediments.

  9. The Renewal of Fresh Water Through Treatment Wetlands: A Global Model

    NASA Astrophysics Data System (ADS)

    Bradford, M.; Fraser, L.; Steer, D.

    2001-05-01

    We present a global model that incorporates population growth, freshwater supply, dam construction, and, most importantly, an estimate of the returns of freshwater by the treatment of wastewater through wetlands. By including treatment wetlands within the global hydrological cycle, we estimate that humans can reduce the annual appropriation of freshwater in 2025 to 52%, even with the assumption that per capita rate of water use is increasing. The diminishing world supply and availability of freshwater is forcing a general re-assessment of freshwater use and the treatment of wastewater. Even with an increase in the construction of dams, the rate of population growth and the projected amount of future water use far surpasses the rate of supply. An earlier global model estimated that humans appropriated 52% of the annual accessible freshwater in 1990, and would appropriate at least 72% in 2025. This alarming figure is actually a very conservative estimate considering that the per capita rate of increase of water use is increasing. If per capita rate of increase was accounted for in the model, 99% of accessible freshwater will be appropriated in 2025. The use of constructed and natural wetlands for the treatment of wastewater may be an effective worldwide tool to help address the problem of fresh water availability.

  10. 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.

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

    PubMed

    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 R(2) = 0 .99396.

  12. 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.

  13. Modeling of the buccal and lingual bone walls of fresh extraction sites following implant installation.

    PubMed

    Araújo, Mauricio G; Wennström, Jan L; Lindhe, Jan

    2006-12-01

    To determine whether the reduction of the alveolar ridge that occurs following tooth extraction and implant placement is influenced by the size of the hard tissue walls of the socket. Six beagle dogs were used. The third premolar and first molar in both quadrants of the mandible were used. Mucoperiostal flaps were elevated and the distal roots were removed. Implants were installed in the fresh extraction socket in one side of the mandible. The flaps were replaced to allow a semi-submerged healing. The procedure was repeated in the contra later side of the mandible after 2 months. The animals were sacrificed 1 month after the final implant installation. The mandibles were dissected, and each implant site was removed and processed for ground sectioning. Marked hard tissue alterations occurred during healing following tooth extraction and implant installation in the socket. The marginal gap that was present between the implant and the walls of the socket at implantation disappeared as a result of bone fill and resorption of the bone crest. The modeling in the marginal defect region was accompanied by marked attenuation of the dimensions of both the delicate buccal and the wider lingual bone wall. Bone loss at molar sites was more pronounced than at the premolar locations. Implant placement failed to preserve the hard tissue dimension of the ridge following tooth extraction. The buccal as well as the lingual bone walls were resorbed. At the buccal aspect, this resulted in some marginal loss of osseointegration.

  14. [Orthogonal experiment using SFE-CO2 in extraction of essential oil from fresh Houttuynia cordata and analysis of essential oil by GC-MS].

    PubMed

    Meng, Jiang; Dong, Xiao-ping; Zhou, Yi-sheng; Jiang, Zhi-hong; Leung, Kelvin Sze-Yin; Zhao, Zhong-zhen

    2007-02-01

    To optimize the extraction procedure of essential oil from H. cordata using the SFE-CO2 and analyze the chemical composition of the essential oil. The extraction procedure of essential oil from fresh H. cordata was optimized with the orthogonal experiment. Essential oil of fresh H. cordata was analysed by GC-MS. The optimize preparative procedure was as follow: essential oil of H. cordata was extracted at a temperature of 35 degrees C, pressure of 15,000 kPa for 20 min. 38 chemical components were identified and the relative contents were quantified. The optimum preparative procedure is reliable and can guarantee the quality of essential oil.

  15. Modelling of microbial activity and prediction of shelf life for packed fresh fish.

    PubMed

    Dalgaard, P

    1995-08-01

    Prediction of shelf life based on growth of specific spoilage organisms (SSO) in model substrates was studied. The effect of CO2 on the growth kinetics for Photobacterium phosphoreum and Shewanella putrefaciens was quantified and modelled. Results showed that microbial spoilage of packed cod stored with various concentrations of CO2 was accurately predicted from the effect of CO2 on P. phosphoreum grown in model substrates. The short shelf life extensions previously reported for packed cod therefore can be explained by the high CO2 resistance of this Gram negative organism. S. putrefaciens was very sensitive to CO2 and growth rates could not be related to the shelf life of packed cod. Growth curves without lag phases were found for all concentrations of CO2 and for both the microorganisms studied. For the fitting of these growth curves the log-transformed Logistic models were selected after comparison with the 'modified Gompertz' models and with the model of Baranyi et al. (1993). The effect of CO2 on mu max was well described by a 2 parameter square root model. Validation of kinetic models by comparison of shelf life predictions with shelf life determined by sensory evaluations in product experiments was preferred for comparison of microbial growth rates determined in product and model system experiments. Kinetic modelling was found to be valuable for both evaluation and prediction of microbial fish spoilage and an iterative approach for development of kinetic shelf life models was suggested.

  16. Numerical Modeling Experiments

    DTIC Science & Technology

    1974-09-01

    presence of clouds is associated with the occurvence of condensation in the atmospheric models. Cloudiness 3t a particulat grid point is introduced -4...when saturation is predicted as a result of either large-scale moisture flux convergence or vertical convective adjustment. In most models such clouds ... cloud top, cloud thickness, and liquid-water content. In some general circulation models the local fractional convective cloud amountv tre taken

  17. 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.

  18. 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…

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

    USDA-ARS?s Scientific Manuscript database

    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...

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

    USDA-ARS?s Scientific Manuscript database

    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...

  1. 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%. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Kinetic and equilibrium modeling of chromium (VI) biosorption on fresh and spent Spirulina platensis/Chlorella vulgaris biomass.

    PubMed

    Gokhale, S V; Jyoti, K K; Lele, S S

    2008-06-01

    Biosorption of chromium (VI) was studied using both fresh and spent algal biomass of Spirulina platensis and Chlorella vulgaris. Both showed comparable behavior suggesting that biosorption is primarily a surface phenomenon. Biosorption rate was very fast during the first five minutes, in which almost 50% of the chromium (VI) was adsorbed. Two step kinetic model was proposed for biosorption. Equilibrium data obeyed Freundlich and Langmuir adsorption isotherms. Fresh algal biomass of S. platensis gave maximum of 73.6% biosorption of chromium (VI) in 100 ppm solution at 1 g l(-1) cell loading. For improved economics, beta-carotene was extracted from S. platensis and the spent biomass was used for chromium (VI) biosorption. The maximum biosorption by spent biomass was increased to 86.2%. Thus, this two step process not only showed improved efficiency in biosorption ( approximately 17% increase) but also gave valuable byproduct, namely beta-carotene.

  3. 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

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

    PubMed

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

    2016-05-01

    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. 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. 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). The use of this novel cadaver model prevented extravasation of fluid

  5. 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

  6. 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).

  7. The Use of a Fresh-Tissue Cadaver Model for the Instruction of Dermatological Procedures: A Laboratory Study for Training Medical Students.

    PubMed

    Cervantes, Jose A; Costello, Collin M; Maarouf, Melody; McCrary, Hilary C; Zeitouni, Nathalie C

    2017-09-01

    A realistic model for the instruction of basic dermatologic procedural skills was developed, while simultaneously increasing medical student exposure to the field of dermatology. The primary purpose of the authors' study was to evaluate the utilization of a fresh-tissue cadaver model (FTCM) as a method for the instruction of common dermatologic procedures. The authors' secondary aim was to assess students' perceived clinical skills and overall perception of the field of dermatology after the lab. Nineteen first- and second-year medical students were pre- and post-tested on their ability to perform punch and excisional biopsies on a fresh-tissue cadaver. Students were then surveyed on their experience. Assessment of the cognitive knowledge gain and technical skills revealed a statistically significant improvement in all categories (p < .001). An analysis of the survey demonstrated that 78.9% were more interested in selecting dermatology as a career and 63.2% of participants were more likely to refer their future patients to a Mohs surgeon. An FTCM is a viable method for the instruction and training of dermatologic procedures. In addition, the authors conclude that an FTCM provides realistic instruction for common dermatologic procedures and enhances medical students' early exposure and interest in the field of dermatology.

  8. Development of a hierarchical Bayesian model to estimate the growth parameters of Listeria monocytogenes in minimally processed fresh leafy salads.

    PubMed

    Crépet, Amélie; Stahl, Valérie; Carlin, Frédéric

    2009-05-31

    The optimal growth rate mu(opt) of Listeria monocytogenes in minimally processed (MP) fresh leafy salads was estimated with a hierarchical Bayesian model at (mean+/-standard deviation) 0.33+/-0.16 h(-1). This mu(opt) value was much lower on average than that in nutrient broth, liquid dairy, meat and seafood products (0.7-1.3 h(-1)), and of the same order of magnitude as in cheese. Cardinal temperatures T(min), T(opt) and T(max) were determined at -4.5+/-1.3 degrees C, 37.1+/-1.3 degrees C and 45.4+/-1.2 degrees C respectively. These parameters were determined from 206 growth curves of L. monocytogenes in MP fresh leafy salads (lettuce including iceberg lettuce, broad leaf endive, curly leaf endive, lamb's lettuce, and mixtures of them) selected in the scientific literature and in technical reports. The adequacy of the model was evaluated by comparing observed data (bacterial concentrations at each experimental time for the completion of the 206 growth curves, mean log(10) increase at selected times and temperatures, L. monocytogenes concentrations in naturally contaminated MP iceberg lettuce) with the distribution of the predicted data generated by the model. The sensitivity of the model to assumptions about the prior values also was tested. The observed values mostly fell into the 95% credible interval of the distribution of predicted values. The mu(opt) and its uncertainty determined in this work could be used in quantitative microbial risk assessment for L. monocytogenes in minimally processed fresh leafy salads.

  9. 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.

  10. Extension of the prognostic model of sea surface temperature to rain-induced cool and fresh lenses

    NASA Astrophysics Data System (ADS)

    Bellenger, Hugo; Drushka, Kyla; Asher, William; Reverdin, Gilles; Katsumata, Masaki; Watanabe, Michio

    2017-01-01

    The Zeng and Beljaars (2005) sea surface temperature prognostic scheme, developed to represent diurnal warming, is extended to represent rain-induced freshening and cooling. Effects of rain on salinity and temperature in the molecular skin layer (first few hundred micrometers) and the near-surface turbulent layer (first few meters) are separately parameterized by taking into account rain-induced fluxes of sensible heat and freshwater, surface stress, and mixing induced by droplets penetrating the water surface. Numerical results from this scheme are compared to observational data from two field studies of near-surface ocean stratifications caused by rain, to surface drifter observations and to previous computations with an idealized ocean mixed layer model, demonstrating that the scheme produces temperature variations consistent with in situ observations and model results. It reproduces the dependency of salinity on wind and rainfall rate and the lifetime of fresh lenses. In addition, the scheme reproduces the observed lag between temperature and salinity minimum at low wind speed and is sensitive to the peak rain rate for a given amount of rain. Finally, a first assessment of the impact of these fresh lenses on ocean surface variability is given for the near-equatorial western Pacific. In particular, the variability due to the mean rain-induced cooling is comparable to the variability due to the diurnal warming so that they both impact large-scale horizontal surface temperature gradients. The present parameterization can be used in a variety of models to study the impact of rain-induced fresh and cool lenses at different spatial and temporal scales.

  11. PETN ignition experiments and models.

    PubMed

    Hobbs, Michael L; Wente, William B; Kaneshige, Michael J

    2010-04-29

    Ignition experiments from various sources, including our own laboratory, have been used to develop a simple ignition model for pentaerythritol tetranitrate (PETN). The experiments consist of differential thermal analysis, thermogravimetric analysis, differential scanning calorimetry, beaker tests, one-dimensional time to explosion tests, Sandia's instrumented thermal ignition tests (SITI), and thermal ignition of nonelectrical detonators. The model developed using this data consists of a one-step, first-order, pressure-independent mechanism used to predict pressure, temperature, and time to ignition for various configurations. The model was used to assess the state of the degraded PETN at the onset of ignition. We propose that cookoff violence for PETN can be correlated with the extent of reaction at the onset of ignition. This hypothesis was tested by evaluating metal deformation produced from detonators encased in copper as well as comparing postignition photos of the SITI experiments.

  12. 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.

  13. 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.

  14. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Application of the distributed activation energy model to the kinetic study of pyrolysis of the fresh water algae Chlorococcum humicola.

    PubMed

    Kirtania, Kawnish; Bhattacharya, Sankar

    2012-03-01

    Apart from capturing carbon dioxide, fresh water algae can be used to produce biofuel. To assess the energy potential of Chlorococcum humicola, the alga's pyrolytic behavior was studied at heating rates of 5-20K/min in a thermobalance. To model the weight loss characteristics, an algorithm was developed based on the distributed activation energy model and applied to experimental data to extract the kinetics of the decomposition process. When the kinetic parameters estimated by this method were applied to another set of experimental data which were not used to estimate the parameters, the model was capable of predicting the pyrolysis behavior, in the new set of data with a R(2) value of 0.999479. The slow weight loss, that took place at the end of the pyrolysis process, was also accounted for by the proposed algorithm which is capable of predicting the pyrolysis kinetics of C. humicola at different heating rates.

  16. Considerations for ex vivo thermal tissue testing exemplified using the fresh porcine longissimus muscle model for endometrial ablation

    NASA Astrophysics Data System (ADS)

    Fugett, James H.; Bennett, Haydon E.; Shrout, Joshua L.; Coad, James E.

    2017-02-01

    Expansions in minimally invasive medical devices and technologies with thermal mechanisms of action are continuing to advance the practice of medicine. These expansions have led to an increasing need for appropriate animal models to validate and quantify device performance. The planning of these studies should take into consideration a variety of parameters, including the appropriate animal model (test system - ex vivo or in vivo; species; tissue type), treatment conditions (test conditions), predicate device selection (as appropriate, control article), study timing (Day 0 acute to more than Day 90 chronic survival studies), and methods of tissue analysis (tissue dissection - staining methods). These considerations are discussed and illustrated using the fresh extirpated porcine longissimus muscle model for endometrial ablation.

  17. A Fresh Cadaver Model for the Instruction of Ultrasound-Guided Fine-Needle Aspiration of Thyroid Nodules.

    PubMed

    McCrary, Hilary C; Faucett, Erynne A; Hurbon, Audriana N; Milinic, Tijana; Cervantes, Jose A; Kent, Sean L; Adamas-Rappaport, William J

    2017-07-01

    Objective The aim of our study is to determine if a fresh cadaver model (FCM) for the instruction of ultrasound (US)-guided fine-needle aspiration (FNA) of thyroid nodules is a practical method for instruction. Study Design Pre- and postinstruction assessment of medical students' ability to perform US-guided FNA of artificially created thyroid nodules placed adjacent to the thyroid gland of a fresh cadaver. Setting University-based fresh cadaver laboratory. Subjects and Methods Study participants included a total of 17 first- and second-year medical students with minimal US training. Technical skills were assessed using a 10-item checklist. In addition, a cognitive assessment regarding the indications, contraindications, and complications of the procedure was completed. A postinstruction assessment was provided for participants 5 weeks after their initial assessment. Differences between pre- and postinstruction assessment scores of technical skills were analyzed using McNemar's test. The mean cognitive knowledge gain was analyzed using a paired 2-sample t test. Results Eight of 10 items on the skills checklist were statistically significant between pre- and postinstruction skills assessment ( P < .05). There was a statistically significant change in cognitive knowledge gain regarding the contraindications of the procedure ( P = .001), but not for indications or complications ( P = .104 and P = .111, respectively). Conclusion US-guided FNA continues to be an important diagnostic procedure in the workup of thyroid nodules, making it an essential skill to integrate into surgical skills lab. Our FCM for the instruction of US-guided FNA is the first of its kind, and this pilot study shows this is a viable method for instruction.

  18. Numerical Modeling of LCROSS experiment

    NASA Astrophysics Data System (ADS)

    Sultanov, V. G.; Kim, V. V.; Matveichev, A. V.; Zhukov, B. G.; Lomonosov, I. V.

    2009-06-01

    The mission objectives of the Lunar Crater Observation and Sensing Satellite (LCROSS) include confirming the presence or absence of water ice in a permanently shadowed crater in the Moon's polar regions. In this research we present results of numerical modeling of forthcoming LCROSS experiment. The parallel FPIC3D gas dynamic code with implemented realistic equations of state (EOS) and constitutive relations [1] was used. New wide--range EOS for lunar ground was developed. We carried out calculations of impact of model body on the lunar surface at different angels. Situations of impact on dry and water ice--contained lunar ground were also taken into account. Modeling results are given for crater's shape and size along with amount of ejecta. [4pt] [1] V.E. Fortov, V.V. Kim, I.V. Lomonosov, A.V. Matveichev, A.V. Ostrik. Numerical modeling of hypervelocity impacts, Intern J Impact Engeneering, 33, 244-253 (2006)

  19. 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…

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

    PubMed

    Hong, Yoon-Ki; Yoon, Won Byong; Huang, Lihan; Yuk, Hyun-Gyun

    2014-06-01

    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 4-strain cocktail of L. monocytogenes (∼3.2 log CFU/g), were exposed to constant storage temperatures held at 10, 15, 20, 25, or 30 °C. All growth curves of L. monocytogenes were fitted to the Baranyi, modified Gompertz, and Huang models. Regardless of conditions under which cells grew, the time needed to reach 5 log CFU/g decreased with the elevated storage temperature. Experimental results showed that there were no significant differences (P > 0.05) in the maximum growth rate k (log CFU/g h(-1) ) and lag phase duration λ (h) between the cultures of L. monocytogenes with or without previous cold-adaption treatments. No distinct difference was observed in the growth pattern among 3 primary models at various storage temperatures. The growth curves of secondary modeling were fitted on an Arrhenius-type model for describing the relationship between k and temperature of the L. monocytogenes on fresh-cut cantaloupe from 10 to 30 °C. The root mean square error values of secondary models for non- and cold-adapted cells were 0.018, 0.021, and 0.024, and 0.039, 0.026, and 0.017 at the modified Gompertz, Baranyi, and Huang model, respectively, indicating that these 3 models presented the good statistical fit. This study may provide valuable information to predict the growth of L. monocytogenes on fresh-cut cantaloupes at different storage conditions. Listeriosis has occurred and increased along with the increased demand of fresh and fresh-cut fruits and vegetables. This study was conducted to predict the growth of non- and cold-adapted L. monocytogenes on fresh-cut cantaloupe at different temperature using mathematical model. These results can be helpful for risk assessments of L. monocytogenes in fresh-cut cantaloupe. This study provides valuable

  1. [Fresh whole blood transfusion for war surgery: the experience of the Kabul French combat support hospital from 2006 to 2009].

    PubMed

    Daban, J-L; Kerleguer, A; Clavier, B; Salliol, A; Ausset, S

    2012-11-01

    The specificities of military medicine have led to the maintenance of fresh whole blood (FWB) transfusion. The aim of our study was to evaluate this practice at the French military hospital in Kabul between 2006-2009. During our study period, 19 FWB transfusions were performed and the data from 15 FWB transfusions could be analyzed. We studied the number of units by recipient, the characteristics of recipients, the results of blood tests performed after transfusion, the incidents in donors and recipients, the period for obtaining a unit of FWB and mortality of recipients. A total of 66 units of FWB were transfused in 15 patients. The median number of FWB units transfused was three per patient. Thirteen out of 15 (87%) were combat-related casualties. All units were tested before transfusion for HIV with rapid diagnostic tests. Every blood samples of donors were negative for pathogens screened at the French Blood Service. No incident in donors and in recipients was reported. The average time between collection and transfusion was 140±197minutes (median 43min). Mortality in recipients was 27% (n=4). In our study, the FWB transfusion was not associated with incidents. Nonetheless, this practice should be used only for exceptional situations like military conflicts where risks of FWB are lower than the absence of transfusion. Copyright © 2012 Société française d’anesthésie et de réanimation (Sfar). Published by Elsevier SAS. All rights reserved.

  2. Isolation of lactic acid bacteria from pao cai, a Chinese traditional fermented vegetable, with inhibitory activity against Salmonella associated with fresh-cut apple, using a modelling study.

    PubMed

    Luo, W; Chen, M; Chen, A; Dong, W; Hou, X; Pu, B

    2015-04-01

    To isolate lactic acid bacteria (LAB) from pao cai, a Chinese traditional fermented vegetable, with outstanding inhibitory activity against Salmonella inoculated on fresh-cut apple, using a modelling method. Four kinds of pao cai were selected. A total of 122 isolates exhibited typical LAB characteristics: Gram-positive and catalase negative, among which 104 (85·24%) colonies showed antibacterial activity against Salmonella by the well diffusion assay. Four colonies showing maximum antibacterial radius against Salmonella were selected to co-inoculate with Salmonella on fresh-cut apple and stored at 10°C, further identified as three strains of Lactobacillus plantarum and one strain of Lactobacillus brevis by 16s rRNA gene sequence analysis. The modified Gompertz model was employed to analyse the growth of the micro-organisms on apple wedges. Two of the four selected strains showed antagonistic activity against Salmonella on fresh-cut apple, one of which, RD1, exhibited best inhibitory activity (Salmonella were greatly inhibited when co-inoculated with RD1 at 10°C at 168 h). No deterioration in odour or appearance of the apple piece was observed by the triangle test when fresh-cut apple was inoculated with RD1. The mathematical modelling method is essential to select LAB with outstanding inhibitory activity against Salmonella associated with fresh-cut apple. LAB RD1 holds promise for the preservation of fresh-cut apple. This study provided a new method on fresh-cut product preservation. Besides, to make the LAB isolating procedure a more correct one, this study first added the mathematical modelling method to the isolating procedure. © 2014 The Society for Applied Microbiology.

  3. 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

    2015-09-02

    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.

  4. Classification and coding of commercial fishing injuries by work processes: an experience in the Danish fresh market fishing industry.

    PubMed

    Jensen, O C; Stage, S; Noer, P

    2005-06-01

    Work-related injuries in commercial fishing are of concern internationally. To better identify the causes of injury, this study coded occupational injuries by working processes in commercial fishing for fresh market fish. A classification system of the work processes was developed by participation in fishing vessel trips where observations and video recordings of the work operations on board were collected. Subsequently the system was pilot tested using the Danish Maritime Authority injury reports. The developed classification system contains 17 main categories and up to 13 sub-categories of the work processes for each of the five different types of fishing. A total of 620 injury reports were reviewed and coded. Five percent (n = 33) of these were fatal injuries. The working processes were identified and coded according to the developed classification system for 553 (89%) injury reports: Danish seiner (n = 83), gill-netter (n = 122), beam trawler (n = 71), twin-trawler 2-T (n = 96), single/pair trawler 1-T (n = 181). Sixty-seven (11%) of the reports were unclassifiable due to lack of information. Preparing, shooting, and hauling of the gear and nets accounted for 50% of the injuries; they were most serious type of injuries such as fractures and sprains. Walking about the ship, in particular embarking and disembarking, climbing and descending ladders accounted for nearly one-fifth of the injuries. We found that the working processes related to working with the gear and nets vary greatly in the different fishing methods. Coding of the injuries to the specific working processes allows for targeted prevention efforts.

  5. The effect of different levels of sunflower head pith addition on the properties of model system emulsions prepared from fresh and frozen beef.

    PubMed

    Sariçoban, Cemalettin; Yilmaz, Mustafa Tahsin; Karakaya, Mustafa; Tiske, Sümeyra Sultan

    2010-01-01

    The effect of sunflower head pith on the functional properties of emulsions was studied by using a model system. Oil/water (O/W) model emulsion systems were prepared from fresh and frozen beef by the addition of the pith at five concentrations. Emulsion capacity (EC), stability (ES), viscosity (EV), colour and flow properties of the prepared model system emulsions were analyzed. The pith addition increased the EC and ES and the highest EC and ES values were reached when 5% of pith added; however, further increase in the pith concentration caused an inverse trend in these values. Fresh beef emulsions had higher EC and ES values than did frozen beef emulsions. One percent pith concentration was the critic level for the EV values of fresh beef emulsions. EV values of the emulsions reached a maximum level at 5% pith level, followed by a decrease at 7% pit level.

  6. 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

  7. [Study on modeling method of total viable count of fresh pork meat based on hyperspectral imaging system].

    PubMed

    Wang, Wei; Peng, Yan-Kun; Zhang, Xiao-Li

    2010-02-01

    Once the total viable count (TVC) of bacteria in fresh pork meat exceeds a certain number, it will become pathogenic bacteria. The present paper is to explore the feasibility of hyperspectral imaging technology combined with relevant modeling method for the prediction of TVC in fresh pork meat. For the certain kind of problem that has remarkable nonlinear characteristic and contains few samples, as well as the problem that has large amount of data used to express the information of spectrum and space dimension, it is crucial to choose a logical modeling method in order to achieve good prediction result. Based on the comparative result of partial least-squares regression (PLSR), artificial neural networks (ANNs) and least square support vector machines (LS-SVM), the authors found that the PLSR method was helpless for nonlinear regression problem, and the ANNs method couldn't get approving prediction result for few samples problem, however the prediction models based on LS-SVM can give attention to the little training error and the favorable generalization ability as soon as possible, and can make them well synchronously. Therefore LS-SVM was adopted as the modeling method to predict the TVC of pork meat. Then the TVC prediction model was constructed using all the 512 wavelength data acquired by the hyperspectral imaging system. The determination coefficient between the TVC obtained with the standard plate count for bacterial colonies method and the LS-SVM prediction result was 0.987 2 and 0.942 6 for the samples of calibration set and prediction set respectively, also the root mean square error of calibration (RMSEC) and the root mean square error of prediction (RMSEP) was 0.207 1 and 0.217 6 individually, and the result was considerably better than that of MLR, PLSR and ANNs method. This research demonstrates that using the hyperspectral imaging system coupled with the LS-SVM modeling method is a valid means for quick and nondestructive determination of TVC of pork

  8. 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.

  9. Methane production rate studies and gas flow modeling for the fresh kills landfill. Interim report

    SciTech Connect

    Kunz, C.O.; Lu, A.H.

    1980-11-01

    Methane is produced in landfills by anaerobic bacteria in the digestion of various organic materials found in the wastes. With the increasing cost of fuels the recovery of methane can be economic from some landfills. The rate of methane production can vary widely depending on factors such as the moisture content of the wastes, the pH, toxicity, temperature and amount of organic material available. Information regarding the rate of gas production and gas flow during pumping is needed to determine the potential of a site for methane recovery and in the design of a recovery system. The primary objective of this study was to develop gas flow models based on measurements of the pressure differential between landfill gas and atmospheric pressure that would enable the rate of gas production to be estimated. In the course of this investigation two landfill gas flow models were developed; a static model and a dynamic model.

  10. Methane-production-rate studies and gas-flow modeling for the Fresh Kills landfill

    SciTech Connect

    Kunz, C.O.; Lu, A.H.

    1980-11-01

    Methane is produced in landfills by anaerobic bacteria in the digestion of various organic materials found in the wastes. With the increasing cost of fuels the recovery of methane can be economic for some landfills. The rate of methane production can vary widely depending on factors such as the moisture content of the wastes, the pH, toxicity, temperature and the amount of organic material available. Information regarding the rate of gas production and gas flow during pumping is needed to determine the potential of a site for methane recovery and in the design of a recovery system. The primary objective of this study was to develop gas flow models based on measurements of the pressure differential between landfill gas and atmospheric pressure that would enable the rate of gas production to be estimated. In the course of this investigation two landfill gas flow models were developed; a static model and a dynamic model.

  11. Reprogramming somatic cells to pluripotency: a fresh look at Yamanaka's model.

    PubMed

    Li, Yangxin; Shen, Zhenya; Shelat, Harnath; Geng, Yong-Jian

    2013-12-01

    In 2006, Dr Shinya Yamanaka succeeded to reprogram somatic cells into pluripotent stem cells (iPSC) by delivering the genes encoding Oct4, Sox2, Klf4, and c-Myc. This achievement represents a fundamental breakthrough in stem cell biology and opens up a new era in regenerative medicine. However, the molecular processes by which somatic cells are reprogrammed into iPSC remain poorly understood. In 2009, Yamanaka proposed the elite and stochastic models for reprogramming mechanisms. To date, many investigators in the field of iPSC research support the concept of stochastic model, i.e., somatic cell reprogramming is an event of epigenetic transformation. A mathematical model, f (Cd, k), has also been proposed to predict the stochastic process. Here we wish to revisit the Yamanaka model and summarize the recent advances in this research field.

  12. On the Gause predator-prey model with a refuge: a fresh look at the history.

    PubMed

    Křivan, Vlastimil

    2011-04-07

    This article re-analyses a prey-predator model with a refuge introduced by one of the founders of population ecology Gause and his co-workers to explain discrepancies between their observations and predictions of the Lotka-Volterra prey-predator model. They replaced the linear functional response used by Lotka and Volterra by a saturating functional response with a discontinuity at a critical prey density. At concentrations below this critical density prey were effectively in a refuge while at a higher densities they were available to predators. Thus, their functional response was of the Holling type III. They analyzed this model and predicted existence of a limit cycle in predator-prey dynamics. In this article I show that their model is ill posed, because trajectories are not well defined. Using the Filippov method, I define and analyze solutions of the Gause model. I show that depending on parameter values, there are three possibilities: (1) trajectories converge to a limit cycle, as predicted by Gause, (2) trajectories converge to an equilibrium, or (3) the prey population escapes predator control and grows to infinity.

  13. A fresh view of cosmological models describing very early universe: General solution of the dynamical equations

    NASA Astrophysics Data System (ADS)

    Filippov, A. T.

    2017-03-01

    The dynamics of any spherical cosmology with a scalar field (`scalaron') coupling to gravity is described by the nonlinear second-order differential equations for two metric functions and the scalaron depending on the `time' parameter. The equations depend on the scalaron potential and on arbitrary gauge function that describes time parameterizations. This dynamical system can be integrated for flat, isotropic models with very special potentials. But, somewhat unexpectedly, replacing the independent variable t by one of the metric functions allows us to completely integrate the general spherical theory in any gauge and with arbitrary potentials. In this approach, inflationary solutions can be easily identified, explicitly derived, and compared to the standard approximate expressions. This approach is also applicable to intrinsically anisotropic models with a massive vector field (`vecton') as well as to some non-inflationary models.

  14. Harmonized, distributed and nation wide modelling of Nitrogen retention in Danish surface fresh waters

    NASA Astrophysics Data System (ADS)

    Thodsen, Hans; Larsen, Søren E.; Windolf, Jørgen; Bering Ovesen, Niels; Bøgestrand, Jens; Kronvang, Brian

    2010-05-01

    According to the EU Water Framework Directive all freshwater bodies must obtain good ecological status by 2015. In Denmark this means that all lakes with a surface area above 5 ha must be evaluated individually and mitigation measures must be enforced if the ecological status is below "good". In consequence, the nutrient pressures from point and diffuse sources must be assessed based on a quantification of the nutrient loading of each lake. In this study we focus on the loading of nitrogen. Surface water Nitrogen retention is an important parameter in loading estimations of nitrogen to lakes and marine areas. Estimations of the cost, of reducing Nitrogen loadings also largely depends on calculations of surface water retention as large percentages of the load can be removed/ retained in surface waters. Especially the presents of larger lakes on the river network can make a large difference between the loads from different catchments. A standardised calculation on annual (1990 - 2008) Nret percentages has been carried out for all Danish lakes larger than 5 hectares attached to a river network (591 lakes). The Nret calculation is based on water residence time calculations from each lake. A national 3D hydrological model, covering all major parts of the country estimated runoff for lake catchments. The diffuse nitrogen input to each lake was simulated with an empirical nitrogen load model. Where lakes are located upstream/ downstream of each other, a calculation chain involving the nitrogen retention in lakes was created. Harmonized national calculations of river nitrogen retention are carried out on the basis of river length and river width information and information on rivers in forested areas. Each river class is given a specific retention pr. unit area. The total average (1990 - 2008) Nitrogen load to Danish surface waters is modelled to 99000 t/yr. The total surface water retention is estimated to 23700 t/yr (24%). Of the surface water retention, 35% origins from

  15. Growth characteristics and development of a predictive model for Bacillus cereus in fresh wet noodles with added ethanol and thiamine.

    PubMed

    Kim, Bo-Yeon; Lee, Ji-Young; Ha, Sang-Do

    2011-04-01

    Response surface methodology was used to determine growth characteristics and to develop a predictive model to describe specific growth rates of Bacillus cereus in wet noodles containing a combination of ethanol (0 to 2% [vol/wt]) and vitamin B(1) (0 to 2 g/liter). B. cereus F4810/72, which produces an emetic toxin, was used in this study. The noodles containing B. cereus were incubated at 10°C. The growth curves were fitted to the modified Gompertz equation using nonlinear regression, and the growth rate values from the curves were used to establish the predictive model using a response surface methodology quadratic polynomial equation as a function of concentrations of ethanol and vitamin B(1). The model was shown to fit the data very well (r(2) = 0.9505 to 0.9991) and could be used to accurately predict growth rates. The quadratic polynomial model was validated, and the predicted growth rate values were in good agreement with the experimental values. The polynomial model was found to be an appropriate secondary model for growth rate (GR) and lag time (LT) based on the correlation of determination (r(2) = 0.9899 for GR, 0.9782 for LT), bias factor (B(f) = 1.006 for GR, 0.992 for LT), and accuracy factor (A(f) = 1.024 for GR, 1.011 for LT). Thus, this model holds great promise for use in predicting the growth of B. cereus in fresh wet noodles using only the bacterial concentration, an important contribution to the manufacturing of safe products.

  16. Novel robust in vitro hepatitis B virus infection model using fresh human hepatocytes isolated from humanized mice.

    PubMed

    Ishida, Yuji; Yamasaki, Chihiro; Yanagi, Ami; Yoshizane, Yasumi; Fujikawa, Kazuyuki; Watashi, Koichi; Abe, Hiromi; Wakita, Takaji; Hayes, C Nelson; Chayama, Kazuaki; Tateno, Chise

    2015-05-01

    The molecular mechanisms underlying the hepatitis B virus (HBV) life cycle are poorly understood because of the lack of appropriate in vitro infection models. Herein, we report a highly effective in vitro HBV infection system using fresh human hepatocytes (HHs) isolated from chimeric mice with humanized livers. After the inoculation of sera collected from HBV-infected chimeric mice or patients to HHs, we measured levels of HBV DNA, mRNA, covalently closed circular DNA, and viral protein expression in HHs. We investigated the neutralization activity of hepatitis B immune globulin and the effects of siRNA against sodium taurocholate-cotransporting polypeptide and clathrin heavy chain on HBV infection. We confirmed the expression of viral antigens in HHs and the presence of extracellular HBV DNA and hepatitis B surface antigen. The maximum infection rate was approximately 80%. Lamivudine and hepatitis B immune globulin treatment reduced HBV DNA levels in a dose-dependent manner. Knockdown of sodium taurocholate-cotransporting polypeptide and clathrin heavy chain significantly reduced the levels of hepatitis B surface antigen. Infection was successfully established using different donor HHs and inocula. Elevation of extracellular HBV DNA levels and the increase of HBV-positive HHs were blocked by continuous hepatitis B immune globulin treatment, indicating virus spread in this model. Chimeric mouse-derived HHs provide a robust in vitro infection model that can completely support the HBV life cycle. Copyright © 2015 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  17. A Fresh Look at Flooring Costs. A Report on a Survey of User Experience Compiled by Armstrong Cork Company.

    ERIC Educational Resources Information Center

    Armstrong Cork Co., Lancaster, PA.

    Survey information based on actual flooring installations in several types of buildings and traffic conditions, representing nearly 113 million square feet of actual user experience, is contained in this comprehensive report compiled by the Armstrong Cork Company. The comparative figures provided by these users clearly establish that--(1) the…

  18. A Fresh Look at the Classical Approach to Homogeneous Solid Propellant Combustion Modeling

    DTIC Science & Technology

    1982-10-01

    CLASSIFICATION OF THIS PAGE (TWien Data Bntarod) REPORT DOCUMENTATION PAGE READ INSTRUCTIONS BEFORE COMPLETING FORM 1. REPORT NUMBER Technical...block number) Solid propellant Temperature sensitivity Combustion Modeling Pressure index 20. ABSTRACT fCbrrtfiiue aa rmraram «M» ft...pressure index is exactly v/2 so that the solid regression rate has much the same character over at least some pressure range. In general the

  19. 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

  20. Polycrystal models to fit experiments

    SciTech Connect

    Kocks, U.F.; Necker, C.T.

    1994-07-01

    Two problems in the modeling of polycrystal plasticity are addressed in which some parameter can best be determined by matching with experiment, although the principles of the underlying mechanisms are presumed known. One of these problems is the transition from ``full constraints`` (FC) to ``relaxed constraints`` (RC) with increasing flatness of the grains. Observed qualitative transitions in texture with strain, such as a transient orthotropic symmetry in torsion textures, can help identify the rate at which the FC-to-RC transition takes place. The second problem is that of the material dependence of deformation textures among the FCC metals which, it is argued, can only be due to a change in deformation modes, i.e., in the shape of the single-crystal yield surface. A heuristic assumption of an increasing importance of (111)<211>-slip as the stacking-fault energy decreases explains the qualitative trend. The quantitative parameter needed has been determined for copper from a match of prediction and experiment over a range of strains.

  1. Response of the CNRM-CM5 coupled model to an enhanced Greenland fresh water flux

    NASA Astrophysics Data System (ADS)

    Rogel, P.; Hamon, M.

    2013-12-01

    We investigate the transient response of the CNRM-CM5 coupled Ocean-Atmosphere model to a strong freshwater forcing around the Greenland coasts. We perturb a 50-year long ensemble of simulation with high-emission of Greenhouse gas (GHG) scenario (RCP8.5). The 5 members of the reference simulation are compared to 5 members of a similar simulation in which the freshwater perturbation is applied. We add 0,00275 Sv to the freshwater fluxes at the Ocean-Atmosphere interface representing 5 times the present estimated melting of the Greenland ice. We highlight that such a freshwater forcing has significant impacts only in the north Atlantic basin where a rapid increase of the sea level rise occurs in the first 30 years, followed by a stagnation period. In the others areas, we point out that the effects of the perturbation is not significant compared to the regional variability. We show relations between sea-level and the meridional overturning circulation (MOC), and attempt to characterize the mechanisms at stake in the CNRM-CM5 model. We thus focus on the effects of the freshwater forcing on the oceanic processes in the North Atlantic basin, especially on the temperature and salinity variability in the subpolar gyre.

  2. Targeting accuracy of transcranial magnetic resonance-guided high-intensity focused ultrasound brain therapy: a fresh cadaver model.

    PubMed

    Chauvet, Dorian; Marsac, Laurent; Pernot, Mathieu; Boch, Anne-Laure; Guillevin, Rémy; Salameh, Najat; Souris, Line; Darrasse, Luc; Fink, Mathias; Tanter, Mickaël; Aubry, Jean-François

    2013-05-01

    This work aimed at evaluating the accuracy of MR-guided high-intensity focused ultrasound (MRgHIFU) brain therapy in human cadaver heads. Eighteen heads of fresh human cadavers were removed with a dedicated protocol preventing intracerebral air penetration. The MR images allowed determination of the ultrasonic target: a part of the thalamic nucleus ventralis intermedius implicated in essential tremor. Osseous aberrations were corrected with simulation-based time reversal by using CT data from the heads. The ultrasonic session was performed with a 512-element phased-array transducer system operating at 1 MHz under stereotactic conditions with thermometric real-time MR monitoring performed using a 1.5-T imager. Dissection, imaging, targeting, and planning have validated the feasibility of this human cadaver model. The average temperature elevation measured by proton resonance frequency shift was 7.9°C ± 3°C. Based on MRI data, the accuracy of MRgHIFU is 0.4 ± 1 mm along the right/left axis, 0.7 ± 1.2 mm along the dorsal/ventral axis, and 0.5 ± 2.4 mm in the rostral/caudal axis. Despite its limits (temperature, vascularization), the human cadaver model is effective for studying the accuracy of MRgHIFU brain therapy. With the 1-MHz system investigated here, there is millimetric accuracy.

  3. Modelling climate change impact on the spatial distribution of fresh water snails hosting trematodes in Zimbabwe.

    PubMed

    Pedersen, Ulrik B; Stendel, Martin; Midzi, Nicholas; Mduluza, Takafira; Soko, White; Stensgaard, Anna-Sofie; Vennervald, Birgitte J; Mukaratirwa, Samson; Kristensen, Thomas K

    2014-12-12

    Freshwater snails are intermediate hosts for a number of trematodes of which some are of medical and veterinary importance. The trematodes rely on specific species of snails to complete their life cycle; hence the ecology of the snails is a key element in transmission of the parasites. More than 200 million people are infected with schistosomes of which 95% live in sub-Saharan Africa and many more are living in areas where transmission is on-going. Human infection with the Fasciola parasite, usually considered more of veterinary concern, has recently been recognised as a human health problem. Many countries have implemented health programmes to reduce morbidity and prevalence of schistosomiasis, and control programmes to mitigate food-borne fascioliasis. As these programmes are resource demanding, baseline information on disease prevalence and distribution becomes of great importance. Such information can be made available and put into practice through maps depicting spatial distribution of the intermediate snail hosts. A biology driven model for the freshwater snails Bulinus globosus, Biomphalaria pfeifferi and Lymnaea natalensis was used to make predictions of snail habitat suitability by including potential underlying environmental and climatic drivers. The snail observation data originated from a nationwide survey in Zimbabwe and the prediction model was parameterised with a high resolution Regional Climate Model. Georeferenced prevalence data on urinary and intestinal schistosomiasis and fascioliasis was used to calibrate the snail habitat suitability predictions to produce binary maps of snail presence and absence. Predicted snail habitat suitability across Zimbabwe, as well as the spatial distribution of snails, is reported for three time slices representative for present (1980-1999) and future climate (2046-2065 and 2080-2099). It is shown from the current study that snail habitat suitability is highly variable in Zimbabwe, with distinct high- and low

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

    NASA Astrophysics Data System (ADS)

    Desai, Hiral; Christian, R. A.

    2010-10-01

    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.

  5. Inactivation of model viruses and bacteria in human fresh frozen plasma using riboflavin and long wave ultraviolet rays

    PubMed Central

    Elikaei, Ameneh; Hosseini, Seyed Masoud; Sharifi, Zohreh

    2017-01-01

    Background and Objectives: Pathogen reduction technologies are among methods to eliminate transfusion transmitted infections. Mirasol method using riboflavin in combination with ultraviolet rays is one of them. The aims of this study were to investigate the effectiveness of Mirasol method to inactivate some model pathogens as well as examination of the sensitivity of plasma proteins after treatment. Materials and Methods: Riboflavin in 50μM concentration and ultraviolet (365 nm) in three different energy doses (3.6, 7.2, and 10.8 j/cm2) were employed to inactivate model pathogens. Four standard viruses were used in this study including Vesicular Stomatitis Virus (VSV), Herpes Simplex Virus1 (HSV-1), Bovine Viral Diarrhea Virus (BVDV) and Polio Virus. 50% Tissue Culture Infectious Dose (TCID50) and Reed–Muench Methods were used to estimate viruses’ titers. E. coli and Staphylococcus aureus were used as bacterial models. Four plasma proteins including factor V, VIII, fibrinogen and antithromin were used to determine their sensitivity to pathogen inactivation treatment. Results: The most pathogen reduction titre was determined for 15 minutes irradiation period equal to 10.8 J/cm2 that is corresponding to Log 6.10 for BVDV, Log 6.09 for HSV-1, Log 6.62 for VSV and Log 3.36 for Polio. Bacterial reduction titer was Log 6.94 for E. coli and Log 7.00 for S. aureus. Indicator proteins for plasma activity were determined to be 75% for factor V, 88% for factor VIII, 52% for fibrinogen and 94% for antithrombin. Conclusion: Results showed that the employed method can inactivate most of the pathogens in fresh frozen plasma. The acceptable activities of selected plasma proteins remained after treatment. PMID:28775824

  6. 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.

  7. Examination of bacteriophage as a biocontrol method for salmonella on fresh-cut fruit: a model study.

    PubMed

    Leverentz, B; Conway, W S; Alavidze, Z; Janisiewicz, W J; Fuchs, Y; Camp, M J; Chighladze, E; Sulakvelidze, A

    2001-08-01

    The preparation and distribution of fresh-cut produce is a rapidly developing industry that provides the consumer with convenient and nutritious food. However, fresh-cut fruits and vegetables may represent an increased food safety concern because of the absence or damage of peel and rind, which normally help reduce colonization of uncut produce with pathogenic bacteria. In this study, we found that Salmonella Enteritidis populations can (i) survive on fresh-cut melons and apples stored at 5 degrees C, (ii) increase up to 2 log units on fresh-cut fruits stored at 10 degrees C, and (iii) increase up to 5 log units at 20 degrees C during a storage period of 168 h. In addition, we examined the effect of lytic, Salmonella-specific phages on reducing Salmonella numbers in experimentally contaminated fresh-cut melons and apples stored at various temperatures. We found that the phage mixture reduced Salmonella populations by approximately 3.5 logs on honeydew melon slices stored at 5 and 10 degrees C and by approximately 2.5 logs on slices stored at 20 degrees C, which is greater than the maximal amount achieved using chemical sanitizers. However, the phages did not significantly reduce Salmonella populations on the apple slices at any of the three temperatures. The titer of the phage preparation remained relatively stable on melon slices, whereas on apple slices the titer decreased to nondetectable levels in 48 h at all temperatures tested. Inactivation of phages, possibly by the acidic pH of apple slices (pH 4.2 versus pH 5.8 for melon slices), may have contributed to their inability to reduce Salmonella contamination in the apple slices. Higher phage concentrations and/or the use of low-pH-tolerant phage mutants may be required to increase the efficacy of the phage treatment in reducing Salmonella contamination of fresh-cut produce with a low pH.

  8. 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.

  9. 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.

  10. Numerical experiments in geomagnetic modeling

    NASA Technical Reports Server (NTRS)

    Cain, Joseph C.; Holter, Bill; Sandee, Daan

    1990-01-01

    Numerical tests were made, using least squares fitting of a spherical harmonic model, to a selection of Magsat data to determine the practical limits of this technique with modern computers. The resulting (M102189) model, whose coefficients were adjusted up to n = 50, was compared with M07AV6, a previous model which used least squares (on vector data) for coefficients up to n = 29, and Gauss-Legendre quadrature (on Z residuals) to adjust the coefficients up to n = 63. For the new least squares adjustment to n = 50 a condition number of 115 was obtained for the solution matrix, with a resulting precision of 11 significant figures. The M102189 model shows a lower and more Gaussian residual distribution than did M07AV6, though the Gaussian envelope fits to the residual distributions, even for the scalar field, gives "standard deviations' never lower than 6 nT, a factor of three higher than the estimated Magsat observational errors. Ionospheric currents are noted to have a significant effect on the coefficients of the internal potential functions.

  11. Effect of Surface Roughness in Model and Fresh Fruit Systems on Microbial Inactivation Efficacy of Cold Atmospheric Pressure Plasma.

    PubMed

    Bhide, Siddharth; Salvi, Deepti; Schaffner, Donald W; Karwe, Mukund V

    2017-08-01

    This study investigates the efficacy of cold atmospheric pressure plasma (CAPP) on microbial inactivation as influenced by surface roughness of two types of surfaces: sandpaper and fresh fruit peel. Different grits of closed-coat sandpaper were selected, with their roughness (Pq) values ranging from 6 to 16 μm. Apple, orange, and cantaloupe peels were selected for roughness values that were similar to the sandpapers. The sandpapers and the fruit peel surfaces were spot inoculated with Enterobacter aerogenes (10(9) CFU/63.64 cm(2)) and exposed to CAPP for 492 s. Similar microbial enumeration techniques were used for both systems to quantify the microbial inactivation. The smoothest sandpaper showed a 0.52-log higher inactivation of E. aerogenes (2.08 log CFU/63.64 cm(2) sandpaper surface inactivation) than did the roughest sandpaper (1.56 log CFU/63.64 cm(2) sandpaper surface inactivation), and the difference was statistically significant (P < 0.05). The smoothest fresh fruit peel surface (apple) showed a 1.25-log higher inactivation of the microorganism (1.86 log CFU/63.64 cm(2) fruit peel surface inactivation) than did the roughest fresh fruit peel surface (cantaloupe; 0.61 log CFU/63.64 cm(2) fruit peel surface inactivation), and the difference was statistically significant (P < 0.05). As the surface roughness increased, microbial inactivation efficacy of CAPP decreased for both systems. The results from sandpaper show that, in a scenario in which the surface roughness was the only parameter of difference, the microbial inactivation efficacy of CAPP decreased with increasing surface roughness. The results from fruit surfaces show high variability and were not directly predictable from the sandpaper data. This suggests that the microbial inactivation efficacy of CAPP in real-world food systems, such as on fresh fruit peels, is affected by factors in addition to surface roughness.

  12. Influence of the natural microbial flora on the acid tolerance response of Listeria monocytogenes in a model system of fresh meat decontamination fluids.

    PubMed

    Samelis, J; Sofos, J N; Kendall, P A; Smith, G C

    2001-06-01

    Depending on its composition and metabolic activity, the natural flora that may be established in a meat plant environment can affect the survival, growth, and acid tolerance response (ATR) of bacterial pathogens present in the same niche. To investigate this hypothesis, changes in populations and ATR of inoculated (10(5) CFU/ml) Listeria monocytogenes were evaluated at 35 degrees C in water (10 or 85 degrees C) or acidic (2% lactic or acetic acid) washings of beef with or without prior filter sterilization. The model experiments were performed at 35 degrees C rather than lower (8.0 log CFU/ml) by day 1. The pH of inoculated water washings decreased or increased depending on absence or presence of natural flora, respectively. These microbial and pH changes modulated the ATR of L. monocytogenes at 35 degrees C. In filter-sterilized water washings, inoculated L. monocytogenes increased its ATR by at least 1.0 log CFU/ml from days 1 to 8, while in unfiltered water washings the pathogen was acid tolerant at day 1 (0.3 to 1.4 log CFU/ml reduction) and became acid sensitive (3.0 to >5.0 log CFU/ml reduction) at day 8. These results suggest that the predominant gram-negative flora of an aerobic fresh meat plant environment may sensitize bacterial pathogens to acid.

  13. 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.

  14. 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.

  15. The database for reaching experiments and models.

    PubMed

    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.

  16. Temperature-Salinity Oscillations, Sudden Transitions, and Hysteresis in Laboratory Experiments and Layered Models

    NASA Astrophysics Data System (ADS)

    Whitehead, J. A.; Te Raa, L.; Tozuka, T.

    2002-12-01

    Simplified box models of the cooling of a salt-stratified ocean have been constructed in the laboratory. A large isothermal basin of water has two layers with differing salinity. Beside this is a small basin connected to the large basin by horizontal tubes at the top, middle and bottom. Calculations indicate that there is a sudden transition and hysteresis between a shallow and a deep convection state if there is a relaxation temperature boundary condition and also if one tube has large flow resistance. Our laboratory studies to date do not clearly show hysteresis but have relatively sudden changes in properties for some parameters. The shallow state is frequently found as an oscillation, and the deep convection state is steady, although thermals produce small rapid fluctuations. Numerical models of the experiments produce qualitative agreement, but quantitative differences are large. In contrast, experiments with a cavity at the bottom of a fresh water reservoir, subjected to steady heating from below and steady salt-water inflow has two distinct states, and exhibits a hysteresis range. Oscillations and transitions like those seen in these experiments may exist in natural bodies with a layer of fresh water cooled from above such as fjords, polar bays, or larger polar regions. The oscillation periods are much greater than either the fresh water or the thermal time scale, making the oscillation mechanism a candidate for climate oscillations. (Much of this work was done at the GFD summer program).

  17. 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.

  18. Modeling choice and valuation in decision experiments.

    PubMed

    Loomes, Graham

    2010-07-01

    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 participants to perceive probabilities and payoffs in a particular way. This model organizes more of the data than any other extant model and generates a number of novel testable implications which are examined with new data.

  19. 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.

  20. STELLA experiment: Design and model predictions

    NASA Astrophysics Data System (ADS)

    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.

    1999-07-01

    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 (IFEL) will serve as a prebuncher to generate ˜1-μm 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 IFEL 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.

  1. 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.

  2. 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.

  3. Using Ecosystem Experiments to Improve Vegetation Models

    DOE PAGES

    Medlyn, Belinda; Zaehle, S; DeKauwe, Martin G.; ...

    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

  4. Scale-model rocket experiments (SRE)

    NASA Astrophysics Data System (ADS)

    Wynne, Douglas G.; Barnell, Mark D.

    1998-07-01

    The Scale model Rocket Experiments (SRE) were conducted in August and September 1997 as a part of the Ballistic Missile Defense Organization (BMDO) Advanced Sensor Technology Program (ASTP) and Discriminating Interceptor Technology Program (DITP). Rome Laboratory (RL) efforts under this effort for ASTP involves the following technology areas: sensor fusion algorithms, high performance processors, and sensor modeling and simulation. In support of the development, test and integration of these areas, Rome Laboratory performed the scale model rocket experiments. This paper details the experiments and results of the scaled rocket experiment as a cost effective, risk reduction experiment to test fusion processor algorithms in a real time environment. The goals of the experiment were to launch, track, fuse, and collect multispectral data from Visible, IR, RADAR and LADAR sensors. The data was collected in real time and was interfaced to the RL-HPC (PARAGON) for real time processing. In June 1997 RL performed the first tests of the series on static targets. The static firings tested data transfers and safety protocols. The RL (Hanscom) IR cameras were calibrated and the proper gain settings were acquired. The next phase of the SRE testing, August 12/13 1997, involved the launching, tracking and acquiring digital IR data into the HPC. In September, RL implemented the next phase of the experiments by incorporating a LADAR and an additional IR sensor from Phillips Laboratory into the system. This paper discusses the success and future work of the SRE.

  5. Pyroelectric Energy Harvesting: Model and Experiments

    DTIC Science & Technology

    2016-05-01

    ARL-TR-7663 ● MAY 2016 US Army Research Laboratory Pyroelectric Energy Harvesting: Model and Experiments by Felisa Sze and...Do not return it to the originator. ARL-TR-7663 ● MAY 2016 US Army Research Laboratory Pyroelectric Energy Harvesting: Model...2016 2. REPORT TYPE Final 3. DATES COVERED (From - To) 07/2015–02/2016 4. TITLE AND SUBTITLE Pyroelectric Energy Harvesting: Model and

  6. 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.

  7. Influence of the Natural Microbial Flora on the Acid Tolerance Response of Listeria monocytogenes in a Model System of Fresh Meat Decontamination Fluids

    PubMed Central

    Samelis, John; Sofos, John N.; Kendall, Patricia A.; Smith, Gary C.

    2001-01-01

    Depending on its composition and metabolic activity, the natural flora that may be established in a meat plant environment can affect the survival, growth, and acid tolerance response (ATR) of bacterial pathogens present in the same niche. To investigate this hypothesis, changes in populations and ATR of inoculated (105 CFU/ml) Listeria monocytogenes were evaluated at 35°C in water (10 or 85°C) or acidic (2% lactic or acetic acid) washings of beef with or without prior filter sterilization. The model experiments were performed at 35°C rather than lower (≤15°C) temperatures to maximize the response of inoculated L. monocytogenes in the washings with or without competitive flora. Acid solution washings were free (<1.0 log CFU/ml) of natural flora before inoculation (day 0), and no microbial growth occurred during storage (35°C, 8 days). Inoculated L. monocytogenes died off (negative enrichment) in acid washings within 24 h. In nonacid (water) washings, the pathogen increased (approximately 1.0 to 2.0 log CFU/ml), irrespective of natural flora, which, when present, predominated (>8.0 log CFU/ml) by day 1. The pH of inoculated water washings decreased or increased depending on absence or presence of natural flora, respectively. These microbial and pH changes modulated the ATR of L. monocytogenes at 35°C. In filter-sterilized water washings, inoculated L. monocytogenes increased its ATR by at least 1.0 log CFU/ml from days 1 to 8, while in unfiltered water washings the pathogen was acid tolerant at day 1 (0.3 to 1.4 log CFU/ml reduction) and became acid sensitive (3.0 to >5.0 log CFU/ml reduction) at day 8. These results suggest that the predominant gram-negative flora of an aerobic fresh meat plant environment may sensitize bacterial pathogens to acid. PMID:11375145

  8. Solar models, neutrino experiments, and helioseismology

    NASA Technical Reports Server (NTRS)

    Bahcall, John N.; Ulrich, Roger K.

    1988-01-01

    The event rates and their recognized uncertainties are calculated for 11 solar neutrino experiments using accurate solar models. These models are also used to evaluate the frequency spectrum of the p and g oscillations modes of the sun. It is shown that the discrepancy between the predicted and observed event rates in the Cl-37 and Kamiokande II experiments cannot be explained by a 'likely' fluctuation in input parameters with the best estimates and uncertainties given in the present study. It is suggested that, whatever the correct solution to the solar neutrino problem, it is unlikely to be a 'trival' error.

  9. Bioavailability trials of beta-carotene from fresh and dehydrated drumstick leaves (Moringa oleifera) in a rat model.

    PubMed

    Nambiar, V S; Seshadri, S

    2001-01-01

    Male albino rats (Charles Foster, n = 40) were fed a synthetic diet deficient in vitamin A for 4 weeks. Six rats died during the depletion period. Of the 34 surviving, 5 rats were continued on the vitamin A deficient diet for 4 more weeks and 24 were repleted with vitamin A (4000 IU/kg diet) in the form of vitamin A acetate (group A, n = 8), fresh drumstick leaves (group B, n = 8) or dehydrated drumstick leaves (group C, n = 8) for 4 weeks. The remaining 10 rats were continued on the vitamin A adequate diet for 4 (n = 5) and 8 weeks, respectively (n = 5). A marked reduction in food intake, body weight, accompanied by clinical signs of vitamin A deficiency and a decline in serum vitamin A (29.2 to 19.1 microg/dL) and liver vitamin A (3.7 to 2.0 microg/dL) were seen at the end of 4 weeks of feeding a vitamin A deficient diet. On repletion significant improvements in clinical signs, food intake and body weights were noted in the three groups compared to the baseline (n = 5) and at the end of 4 weeks of depletion. The gain in body weight was highest for the group repleted with dehydrated drumstick leaves. Among the repleted groups, the serum vitamin A was highest for group A (34.7 microg/dL) given synthetic vitamin A, compared to group B (25.8 microg/dL) and group C (28.2 microg/dL) given drumstick leaves. All these were significantly higher than the serum vitamin A values seen at the end of 4 weeks of depletion (19.1 microg/dL). A significant improvement was also observed in the liver retinol levels on repletion for 4 weeks in the three groups, compared to the vitamin A depleted rats. These results imply that beta-carotene from drumstick leaves was effective in overcoming vitamin A deficiency although serum vitamin A levels remained somewhat lower compared to the group repleted with vitamin A acetate. In terms of growth parameters, the fresh and dehydrated drumstick leaves were better than the synthetic vitamin A. It is therefore concluded that in the developing

  10. Metal powder absorptivity: Modeling and experiment

    SciTech Connect

    Boley, C. D.; Mitchell, S. C.; Rubenchik, A. M.; Wu, S. S. Q.

    2016-08-10

    Here, we present results of numerical modeling and direct calorimetric measurements of the powder absorptivity for a number of metals. The modeling results generally correlate well with experiment. We show that the powder absorptivity is determined, to a great extent, by the absorptivity of a flat surface at normal incidence. Our results allow the prediction of the powder absorptivity from normal flat-surface absorptivity measurements.

  11. Metal powder absorptivity: Modeling and experiment

    SciTech Connect

    Boley, C. D.; Mitchell, S. C.; Rubenchik, A. M.; Wu, S. S. Q.

    2016-08-10

    Here, we present results of numerical modeling and direct calorimetric measurements of the powder absorptivity for a number of metals. The modeling results generally correlate well with experiment. We show that the powder absorptivity is determined, to a great extent, by the absorptivity of a flat surface at normal incidence. Our results allow the prediction of the powder absorptivity from normal flat-surface absorptivity measurements.

  12. 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)

  13. 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)

  14. Fresh water fish, Channa punctatus, as a model for pendimethalin genotoxicity testing: A new approach toward aquatic environmental contaminants.

    PubMed

    Ahmad, Irshad; Ahmad, Masood

    2016-11-01

    Pendimethalin (PND) is one of the common herbicides used worldwide. Fresh water fish, Channa punctatus, was exposed to PND in aquaria wherein its LC50 value was recorded to be 3.6 mg/L. Three sublethal (SL) concentrations, namely, 0.9, 1.8, and 2.7 mg/L were selected for the evaluation of genotoxicity and oxidative stress generated in the fish. In vivo comet assay was carried out in the blood, liver, and gill cells after exposing the fish to aforesaid SL concentrations of PND for 24, 48, 72, and 96 h. The results of the comet assay demonstrated the genotoxicity of PND in all the three tissues. Induction of oxidative stress in the gill cells was affirmed by the increased lipid peroxidation (LPO) and decreased levels of reduced glutathione, superoxide dismutase, and catalase. Frequencies of erythrocytic nuclear abnormalities (ENA) and micronuclei (MN) were also used to assess the genotoxic potential of PND on C. punctatus. MN frequency did not show any enhancement after PND exposure, but the frequency of ENA such as kidney-shaped nuclei, segmented nuclei and lobed nuclei, showed a significant increase after 24-96 h. Thus, ENA seems to be a better biomarker than MN for PND induced genotoxicity. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1520-1529, 2016.

  15. [Evaluation of fresh sample of alfalfa silage through near infrared reflectance spectroscopy (NIRS)].

    PubMed

    Chen, Peng-Fei; Rong, Yu-Ping; Han, Jian-Guo; Wang, Ji-Hua; Zhang, Lu-Da; Xu, Xiao-Jie

    2007-07-01

    It is very important to evaluate the fresh sample of alfalfa silage using near infrared reflectance spectroscopy technology (NIRS) for animal production. The nutrient content of forage means the contents of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) in the forage. Because of the high moisture content, it is difficult to make uniform samples for fresh forage and to get useful information from the spectrum. Therefore, it is hard to use NIRS analysis. In order to evaluate the feasibility of using NIRS to analyse the fresh alfalfa silage, the DM, CP, NDF and ADF contents of fresh alfalfa silage were evaluated by the near infrared reflectance spectroscopy model in this experiment using partial least square regression (PLS), Fourier transform technology and sample preparation with liquid nitrogen technology. The analysis samples were obtained through different cultivars, maturity, cuttings and ensiling method. The cross validation was determined between 0.884 6-0. 989 8. The standard error of cross validation was between 3.9 and 9.7 g x kg(-1) fresh weight. Fifty samples were used to test the performance of the models. The coefficients of correlation between the chemical value and the NIRS value are between 0.939 7 and 0.994 9, and the root mean square errors of prediction are between 1.9 and 8.3 g x kg(-1) fresh weight. The results showed that NIRS could be used to evaluate the nutrition of fresh forage.

  16. Field and modelling investigations of fresh-water plume behaviour in response to infrequent high-precipitation events, Sydney Estuary, Australia

    NASA Astrophysics Data System (ADS)

    B., Serena; Lee | Gavin, F.; Birch | Charles, J.; Lemckert

    2011-05-01

    Runoff from the urban environment is a major contributor of non-point source contamination for many estuaries, yet the ultimate fate of this stormwater within the estuary is frequently unknown in detail. The relationship between catchment rainfall and estuarine response within the Sydney Estuary (Australia) was investigated in the present study. A verified hydrodynamic model (Environmental Fluid Dynamics Computer Code) was utilised in concert with measured salinity data and rainfall measurements to determine the relationship between rainfall and discharge to the estuary, with particular attention being paid to a significant high-precipitation event. A simplified rational method for calculating runoff based upon daily rainfall, subcatchment area and runoff coefficients was found to replicate discharge into the estuary associated with the monitored event. Determining fresh-water supply based upon estuary conditions is a novel technique which may assist those researching systems where field-measured runoff data are not available and where minor field-measured information on catchment characteristics are obtainable. The study concluded that since the monitored fresh-water plume broke down within the estuary, contaminants associated with stormwater runoff due to high-precipitation events (daily rainfall > 50 mm) were retained within the system for a longer period than was previously recognised.

  17. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Modelling growth of Escherichia coli O157:H7 in fresh-cut lettuce submitted to commercial process conditions: chlorine washing and modified atmosphere packaging.

    PubMed

    Posada-Izquierdo, Guiomar D; Pérez-Rodríguez, Fernando; López-Gálvez, Francisco; Allende, Ana; Selma, María V; Gil, María I; Zurera, Gonzalo

    2013-04-01

    Fresh-cut iceberg lettuce inoculated with Escherichia coli O157:H7 was submitted to chlorine washing (150 mg/mL) and modified atmosphere packaging on laboratory scale. Populations of E. coli O157:H7 were assessed in fresh-cut lettuce stored at 4, 8, 13 and 16 °C using 6-8 replicates in each analysis point in order to capture experimental variability. The pathogen was able to grow at temperatures ≥8 °C, although at low temperatures, growth data presented a high variability between replicates. Indeed, at 8 °C after 15 days, some replicates did not show growth while other replicates did present an increase. A growth primary model was fitted to the raw growth data to estimate lag time and maximum growth rate. The prediction and confidence bands for the fitted growth models were estimated based on Monte-Carlo method. The estimated maximum growth rates (log cfu/day) corresponded to 0.14 (95% CI: 0.06-0.31), 0.55 (95% CI: 0.17-1.20) and 1.43 (95% CI: 0.82-2.15) for 8, 13 and 16 °C, respectively. A square-root secondary model was satisfactorily derived from the estimated growth rates (R(2) > 0.80; Bf = 0.97; Af = 1.46). Predictive models and data obtained in this study are intended to improve quantitative risk assessment studies for E. coli O157:H7 in leafy green products.

  19. Cooling tower plume - model and experiment

    NASA Astrophysics Data System (ADS)

    Cizek, Jan; Gemperle, Jiri; Strob, Miroslav; Nozicka, Jiri

    The paper discusses the description of the simple model of the, so-called, steam plume, which in many cases forms during the operation of the evaporative cooling systems of the power plants, or large technological units. The model is based on semi-empirical equations that describe the behaviour of a mixture of two gases in case of the free jet stream. In the conclusion of the paper, a simple experiment is presented through which the results of the designed model shall be validated in the subsequent period.

  20. Fresh frozen cadaver workshops for advanced vascular surgical training.

    PubMed

    Jansen, Shirley; Cowie, Margaret; Linehan, John; Hamdorf, Jeffery M

    2014-11-01

    Reduction in working hours, streamlined training schemes and increasing use of endovascular techniques has meant a reduction in operative experience for newer vascular surgical trainees, especially those exposures which are not routinely performed such as thoracoabdominal, thoracotomy and retroperitoneal aortic, for example. This paper describes an Advanced Anatomy of Exposure course which was designed and convened at the Clinical Training & Evaluation Centre in Western Australia and uses fresh frozen cadavers. Feedback was obtained from the participants who attended over three courses by questionnaire. Feedback was strongly positive for the course meeting both its learning outcomes and personal learning objectives, and in addition, making a significant contribution to specialty skills. Most participants thought the fresh frozen cadaveric model significantly improved the learning objectives for training. The fresh frozen cadaver is an excellent teaching model highly representative of the living open surgical scenario where advanced trainees and newly qualified consultants can improve their operative confidence and consequently patient safety in vascular surgery. An efficient fresh frozen cadaver teaching programme can benefit many health professionals simultaneously maximizing the use of donated human tissue. © 2013 Royal Australasian College of Surgeons.

  1. 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.

  2. 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.

  3. Microbial Performance of Food Safety Control and Assurance Activities in a Fresh Produce Processing Sector Measured Using a Microbial Assessment Scheme and Statistical Modeling.

    PubMed

    Njage, Patrick Murigu Kamau; Sawe, Chemutai Tonui; Onyango, Cecilia Moraa; Habib, I; Njagi, Edmund Njeru; Aerts, Marc; Molenberghs, Geert

    2017-01-01

    Current approaches such as inspections, audits, and end product testing cannot detect the distribution and dynamics of microbial contamination. Despite the implementation of current food safety management systems, foodborne outbreaks linked to fresh produce continue to be reported. A microbial assessment scheme and statistical modeling were used to systematically assess the microbial performance of core control and assurance activities in five Kenyan fresh produce processing and export companies. Generalized linear mixed models and correlated random-effects joint models for multivariate clustered data followed by empirical Bayes estimates enabled the analysis of the probability of contamination across critical sampling locations (CSLs) and factories as a random effect. Salmonella spp. and Listeria monocytogenes were not detected in the final products. However, none of the processors attained the maximum safety level for environmental samples. Escherichia coli was detected in five of the six CSLs, including the final product. Among the processing-environment samples, the hand or glove swabs of personnel revealed a higher level of predicted contamination with E. coli , and 80% of the factories were E. coli positive at this CSL. End products showed higher predicted probabilities of having the lowest level of food safety compared with raw materials. The final products were E. coli positive despite the raw materials being E. coli negative for 60% of the processors. There was a higher probability of contamination with coliforms in water at the inlet than in the final rinse water. Four (80%) of the five assessed processors had poor to unacceptable counts of Enterobacteriaceae on processing surfaces. Personnel-, equipment-, and product-related hygiene measures to improve the performance of preventive and intervention measures are recommended.

  4. 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.

  5. Modeling variability in porescale multiphase flow experiments

    NASA Astrophysics Data System (ADS)

    Ling, Bowen; Bao, Jie; Oostrom, Mart; Battiato, Ilenia; Tartakovsky, Alexandre M.

    2017-07-01

    Microfluidic devices and porescale numerical models are commonly used to study multiphase flow in biological, geological, and engineered porous materials. In this work, we perform a set of drainage and imbibition experiments in six identical microfluidic cells to study the reproducibility of multiphase flow experiments. We observe significant variations in the experimental results, which are smaller during the drainage stage and larger during the imbibition stage. We demonstrate that these variations are due to sub-porescale geometry differences in microcells (because of manufacturing defects) and variations in the boundary condition (i.e., fluctuations in the injection rate inherent to syringe pumps). Computational simulations are conducted using commercial software STAR-CCM+, both with constant and randomly varying injection rates. Stochastic simulations are able to capture variability in the experiments associated with the varying pump injection rate.

  6. 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.

  7. Cell motility: Combining experiments with modeling

    NASA Astrophysics Data System (ADS)

    Rappel, Wouter-Jan

    2013-03-01

    Cell migration and motility is a pervasive process in many biology systems. It involves intra-cellular signal transduction pathways that eventually lead to membrane extension and contraction. Here we describe our efforts to combine quantitative experiments with theoretical and computational modeling to gain fundamental insights into eukaryotic cell motion. In particular, we will focus on the amoeboid motion of Dictyostelium discoideum cells. This work is supported by the National Institutes of Health (P01 GM078586)

  8. 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.

  9. Data Assimilation and Model Evaluation Experiment Datasets.

    NASA Astrophysics Data System (ADS)

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

    1994-05-01

    The Institute for Naval Oceanography, in cooperation with Naval Research Laboratories and universities, executed the Data Assimilation and Model Evaluation Experiment (DAMÉE) 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 theorectical studies, and 3) comparisons with locally detailed observations.

  10. 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.

  11. 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.

  12. Robust linear and non-linear models of NIR spectroscopy for detection and quantification of adulterants in fresh and frozen-thawed minced beef.

    PubMed

    Morsy, Noha; Sun, Da-Wen

    2013-02-01

    This study aimed to evaluate the potential of near infrared spectroscopy (NIRS) as a fast and non-destructive tool for detecting and quantifying different adulterants in fresh and frozen-thawed minced beef. Partial least squares regression (PLSR) models were built under cross validation and tested with different independent data sets, yielding determination coefficients (R(P)(2)) of 0.96, 0.94 and 0.95 with standard error of prediction (SEP) of 5.39, 5.12 and 2.08% (w/w) for minced beef adulterated by pork, fat trimming and offal, respectively. The performance of the developed models declined when the samples were in a frozen-thawed condition, yielding R(P)(2) of 0.93, 0.82 and 0.95 with simultaneous augments in the SEP of 7.11, 9.10 and 2.38% (w/w), respectively. Linear discriminant analysis (LDA), partial least squares-discriminant analysis (PLS-DA) and non-linear regression models (logistic, probit and exponential regression) were developed at the most relevant wavelengths to discriminate between the pure (unadulterated) and adulterated minced beef. The classification accuracy resulting from both types of models was quite high, especially the LDA, PLS-DA and exponential regression models which yielded 100% accuracy. The current study demonstrated that the VIS-NIR spectroscopy can be utilized securely to detect and quantify the amount of adulterants added to the minced beef with acceptable precision and accuracy.

  13. 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.

  14. Tank Pressure Control Experiment and Theoretical Modeling

    NASA Astrophysics Data System (ADS)

    Albayyari, Jihad M.

    1995-01-01

    Future space systems such as Space Station Freedom, and space defense systems will require storage of cryogenic fluids in a low-gravity environment for extended periods of time. Heat leaks to the containment vessel lead to an increase in the temperature and pressure of the fluid. The absence of natural convection results in a non-uniform temperature which exacerbates the pressure increase. Therefore a re-circulating liquid jet is necessary to mix the fluid. Therefore the Tank Pressure Control Experiment (TPCE) was designed. This experiment has been flown twice on the Space Shuttle (STS 43-1991 and STS 52-1992). The experiments used Freon-113 at near saturation conditions to simulate cryogenic fluids in space, with relatively low ullage volume (84 percent liquid fill). The TPCE results showed that low-velocity mixing is effective for pressure control in a nearly full tank. Multiple-burn missions using a single set of cryogenic propellant tanks, however, will consume 50 to 60 percent of the propellant during the first burn. The University of Cincinnati was awarded an In-Space Technology Experiment (IN-STEP) contract to re-fly the TPCE with a 40 percent liquid fill using Freon-113, and to theoretically model the heating and the mixing process inside the tank. Due to the absence of natural convection during the heating phase, a conduction model is needed to determine the temperature increase inside the tank. The heating model determined the time required for the pressure inside the tank to start increasing due to nucleate pool boiling at the heater surface. The mixing model consists of a non-penetrating laminar jet directed toward the liquid-vapor interface in the tank to induce condensation. The mixing model numerically solved the two-dimensional Navier-Stokes, and the energy equations. The model will predict the velocity, pressure, and temperature inside the tank. The model also predicted condensation rate at the interface, which will reduce the pressure in the tank.

  15. 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.

  16. 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

  17. Modelling and experiment of railway ballast vibrations

    NASA Astrophysics Data System (ADS)

    Zhai, W. M.; Wang, K. Y.; Lin, J. H.

    2004-03-01

    The vibration of railway ballast is a key factor to cause track geometry change and increase of track maintenance costs. So far the methods for analyzing and testing the vibration of the granular ballast have not been well formed. In this paper, a five-parameter model for analysis of the ballast vibration is established based upon the hypothesis that the load-transmission from a sleeper to the ballast approximately coincides with the cone distribution. The concepts of shear stiffness and shear damping of the ballast are introduced in the model in order to consider the continuity of the interlocking ballast granules. A full-scale field experiment is carried out to measure the ballast acceleration excited by moving trains. Theoretical simulation results agree well with the measured results. Hence the proposed ballast vibration model has been validated.

  18. 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.

  19. Impact of mixtures of different fresh-cut fruits on respiration and ethylene production rates.

    PubMed

    Mahajan, Pramod V; Luca, Alexandru; Edelenbos, Merete

    2014-07-01

    Packaging and storage of fresh-cut fruits and vegetables are a challenging task, since fresh produce continue to respire and senesce after harvest and processing accelerates the physiological processes. The response on respiration and ethylene production rates of fresh produce to changes in O2 and CO2 concentrations and temperature has been extensively studied for whole fruits but literature is limited on processed and mixed fresh-cut fruits. This study aimed to investigate the effects of mixing various proportions of fresh-cut fruits (melon chunks, apple slices, and pineapples cubes) on respiration and ethylene production rates and to develop predictive models for modified atmosphere packaging. The experiment was designed according to a simplex lattice method and respiration and ethylene production rates were measured at 10 °C. Results showed that single component pineapple cubes, apple slices, and melon chunks, in this order, had significant constant coefficients (P = 0.05) and the greatest impact on respiration rate while the interactive binary and tertiary coefficients were insignificant. For ethylene production rates, single component apple slices, melon chunks, and pineapple cubes, and their 3-component mixtures, in this order, had significant constant coefficients (P = 0.05) while binary coefficients were insignificant. Mathematical models were developed and validated; the cubical model was the best to describe the influence of proportion of fruit on respiration and ethylene production rates, however, considering simplicity the linear part of the model is recommended to quantify respiration and ethylene production rates of mixed fresh-cut fruits. This research helps to quantify the ethylene production and respiration rates of multicomponent mixed fresh-cut fruit, which then can be used for packaging design of fresh-cut produce. © 2014 Institute of Food Technologists®

  20. 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

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

    USDA-ARS?s Scientific Manuscript database

    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...

  3. Fresh Frozen Plasma

    DTIC Science & Technology

    2009-03-01

    therapeutic means). FFP can be prepared either by separation from whole blood or collection via plasmapheresis . Fresh frozen plasma contains the...FFP can be further separated into cryoprecipitate and what is known as “cryo-poor plasma,” a product rarely used for therapeutic means. Plasma is the

  4. Fresh Copernican Crater

    NASA Image and Video Library

    2009-12-21

    A subset of NAC Image M112162602L showing landslides bottom covering impact melt on the floor top of a fresh Copernican-age crater at the edge of Oceanus Procellarum and west of Balboa crater taken by NASA Lunar Reconnaissance Orbiter.

  5. Keeping Teaching Fresh.

    ERIC Educational Resources Information Center

    Al-Bataineh, Adel; Nur-Awaleh, Mohamed

    This paper discusses how experienced teachers can keep their teaching fresh. Though professional development can help teachers stay current with educational techniques and practices, it is often not prioritized. Instructional changes that can recharge teachers so they provide students with optimal learning include: providing regular teacher…

  6. Long-Term Stored Hemoglobin-Vesicles, a Cellular Type of Hemoglobin-Based Oxygen Carrier, Has Resuscitative Effects Comparable to That for Fresh Red Blood Cells in a Rat Model with Massive Hemorrhage without Post-Transfusion Lung Injury

    PubMed Central

    Yamasaki, Keishi; Sakai, Hiromi; Otagiri, Masaki

    2016-01-01

    Hemoglobin-vesicles (HbV), encapsulating highly concentrated human hemoglobin in liposomes, were developed as a substitute for red blood cells (RBC) and their safety and efficacy in transfusion therapy has been confirmed in previous studies. Although HbV suspensions are structurally and physicochemically stabile for least 1-year at room temperature, based on in vitro experiments, the issue of whether the use of long-term stored HbV after a massive hemorrhage can be effective in resuscitations without adverse, post-transfusion effects remains to be clarified. We report herein on a comparison of the systemic response and the induction of organ injuries in hemorrhagic shock model rats resuscitated using 1-year-stored HbV, freshly packed RBC (PRBC-0) and by 28-day-stored packed RBC (PRBC-28). The six-hour mortality after resuscitation was not significantly different among the groups. Arterial blood pressure and blood gas parameters revealed that, using HbV, recovery from the shock state was comparable to that when PRBC-0 was used. Although no significant change was observed in serum parameters reflecting liver and kidney injuries at 6 hours after resuscitation among the three resuscitation groups, results based on Evans Blue and protein leakage in bronchoalveolar lavage fluid, the lung wet/dry weight ratio and histopathological findings indicated that HbV as well as PRBC-0 was less predisposed to result in a post-transfusion lung injury than PRBC-28, as evidenced by low levels of myeloperoxidase accumulation and subsequent oxidative damage in the lung. The findings reported herein indicate that 1-year-stored HbV can effectively function as a resuscitative fluid without the induction of post-transfused lung injury and that it is comparable to fresh PRBC, suggesting that HbV is a promising RBC substitute with a long shelf-life. PMID:27798697

  7. Antitumor activity of enzastaurin (LY317615.HCl) against human cancer cell lines and freshly explanted tumors investigated in in-vitro [corrected] soft-agar cloning experiments.

    PubMed

    Hanauske, Axel-Rainer; Oberschmidt, Olaf; Hanauske-Abel, Hartmut; Lahn, Michael M; Eismann, Ulrike

    2007-06-01

    Enzastaurin (LY317615.HCl) is an antiproliferative agent targeted specifically against PKC-beta. We have investigated the antitumoral effects of Enzastaurin against human cancer cell lines and freshly explanted human tumor tissue. Ten human cancer cell lines (NSCLC, colon, and thyroid) and human tumor specimens from 72 patients were used for in vitro studies in a cloning assay (HTCA). Cell lines and primary tumor cells were exposed to Enzastaurin for either 1 h or 7 days, or for 1 h or 21 days. At clinically achievable concentrations of Enzastaurin, inhibition of cell growth was observed for lung, colorectal, and thyroid cancer cell lines in a concentration dependent manner. Patient specimens exposed 1 h or 21 days to 1,400 nM Enzastaurin demonstrated inhibition rates of 24 and 32%, respectively. Marked inhibitory effects were observed in breast, thyroid, head/neck, non-small cell lung cancer, pancreatic cancer, and melanoma. In addition to its established antiangiogenic effects, Enzastaurin has direct antitumor activity against established human cancer cell lines and primary tumor specimens. This warrants further clinical development in tumors which have been identified to be potentially sensitive to Enzastaurin.

  8. Correction of blood coagulation dysfunction and anemia by supplementation of red blood cell suspension, fresh frozen plasma, and apheresis platelet: results of in vitro hemodilution experiments.

    PubMed

    Li, Ling; Yang, Jiangcun; Sun, Yang; Dang, Qianli; Xu, Cuixiang; Chen, Ping; Ma, Ting; Ren, Jiangkang

    2015-02-01

    This study aimed to determine the optimal composition and timing for the administration of blood supplements during in vivo blood transfusion with red blood cells suspension (pRBC), fresh frozen plasma (FFP), and apheresis platelet (PLT) administered for the correction of anemia and coagulation dysfunction caused by in vitro hemodilution. We collected blood samples from 24 healthy volunteers and prepared various dilutions of whole blood with normal saline: 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8, and 1:9. The diluted blood samples were then supplemented with blood components at various proportions and then analyzed to determine the values of the routine blood indices, coagulation indices, and thromboelastogram measures. At hemodilutions of 40%, 50%, and 60%, the hemoglobin, coagulation indices, and platelet number and function reached critical levels, necessitating supplementation with pRBC, FFP, and PLT, respectively. When hemodilution was 90%, the supplementation required was approximately 1:1.3:0.9 of pRBC/FFP/PLT. The use of pRBC, FFP, and PLT in appropriate proportions can correct the blood coagulation dysfunction and anemia caused by in vitro hemodilution, and these proportions can be used as guidelines for in vivo massive transfusion. Copyright © 2014 Elsevier Inc. All rights reserved.

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

    PubMed

    Haimes, E; Taylor, K

    2009-09-01

    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. 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. 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. 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.

  10. Argonne Bubble Experiment Thermal Model Development II

    SciTech Connect

    Buechler, Cynthia Eileen

    2016-07-01

    This report describes the continuation of the work reported in “Argonne Bubble Experiment Thermal Model Development”. The experiment was performed at Argonne National Laboratory (ANL) in 2014. A rastered 35 MeV electron beam deposited power in a solution of uranyl sulfate, generating heat and radiolytic gas bubbles. Irradiations were performed at three beam power levels, 6, 12 and 15 kW. Solution temperatures were measured by thermocouples, and gas bubble behavior was observed. 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 irradiations. The previous report described an initial analysis performed on a geometry that had not been updated to reflect the as-built solution vessel. Here, the as-built geometry is used. Monte-Carlo N-Particle (MCNP) calculations were performed on the updated geometry, and these results were used to define the power deposition profile for the CFD analyses, which were performed using Fluent, Ver. 16.2. CFD analyses were performed for the 12 and 15 kW irradiations, and further improvements to the model were incorporated, including the consideration of power deposition in nearby vessel components, gas mixture composition, and bubble size distribution. The temperature results of the CFD calculations are compared to experimental measurements.

  11. Strain and stress variations in the human amniotic membrane and fresh corpse autologous sciatic nerve anastomosis in a model of sciatic nerve injury☆

    PubMed Central

    Peng, Chuangang; Zhang, Qiao; Yang, Qi; Zhu, Qingsan

    2012-01-01

    A 10-mm long sciatic nerve injury model was established in fresh normal Chinese patient cadavers. Amniotic membrane was harvested from healthy maternal placentas and was prepared into multilayered, coiled, tubular specimens. Sciatic nerve injury models were respectively anastomosed using the autologous cadaveric sciatic nerve and human amniotic membrane. Tensile test results showed that maximal loading, maximal displacement, maximal stress, and maximal strain of sciatic nerve injury models anastomosed with human amniotic membrane were greater than those in the autologous nerve anastomosis group. The strain-stress curves of the human amniotic membrane and sciatic nerves indicated exponential change at the first phase, which became elastic deformation curves at the second and third phases, and displayed plastic deformation curves at the fourth phase, at which point the specimens lost their bearing capacity. Experimental findings suggested that human amniotic membranes and autologous sciatic nerves exhibit similar stress-strain curves, good elastic properties, and certain strain and stress capabilities in anastomosis of the injured sciatic nerve. PMID:25624801

  12. 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.

  13. 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.

  14. Forces between permanent magnets: experiments and model

    NASA Astrophysics Data System (ADS)

    González, Manuel I.

    2017-03-01

    This work describes a very simple, low-cost experimental setup designed for measuring the force between permanent magnets. The experiment consists of placing one of the magnets on a balance, attaching the other magnet to a vertical height gauge, aligning carefully both magnets and measuring the load on the balance as a function of the gauge reading. A theoretical model is proposed to compute the force, assuming uniform magnetisation and based on laws and techniques accessible to undergraduate students. A comparison between the model and the experimental results is made, and good agreement is found at all distances investigated. In particular, it is also found that the force behaves as r -4 at large distances, as expected.

  15. Bucky gel actuator displacement: experiment and model

    NASA Astrophysics Data System (ADS)

    Ghamsari, A. K.; Jin, Y.; Zegeye, E.; Woldesenbet, E.

    2013-02-01

    Bucky gel actuator (BGA) is a dry electroactive nanocomposite which is driven with a few volts. BGA’s remarkable features make this tri-layered actuator a potential candidate for morphing applications. However, most of these applications would require a better understanding of the effective parameters that influence the BGA displacement. In this study, various sets of experiments were designed to investigate the effect of several parameters on the maximum lateral displacement of BGA. Two input parameters, voltage and frequency, and three material/design parameters, carbon nanotube type, thickness, and weight fraction of constituents were selected. A new thickness ratio term was also introduced to study the role of individual layers on BGA displacement. A model was established to predict BGA maximum displacement based on the effect of these parameters. This model showed good agreement with reported results from the literature. In addition, an important factor in the design of BGA-based devices, lifetime, was investigated.

  16. 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

  17. 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

  18. Electrical Monitoring of Fresh Water Displacement in a Brackish Aquifer During Aquifer Storage and Recovery: Forward and Inverse Modeling Results

    NASA Astrophysics Data System (ADS)

    Levannier, A.; Delhomme, J.

    2003-12-01

    Aquifer storage and recovery (ASR) projects are now used to temporarily store water in the subsurface and to recover it when needed. When freshwater is injected into a brackish aquifer, a transition zone forms, due to mixing, diffusion and gravity. The front displacement and the width of the transition zone depend on the characteristics of the aquifer but, from repeated surveys conducted with an array of downhole electrodes placed against the borehole wall, the changes in the front position/shape can be continuously monitored. Synthetic data were created for a targeted ASR situation through hydrodynamic and hydrodispersive modeling (performed with a finite difference scheme) that gave the salt concentration distribution in the aquifer, as a function of space and time, during ASR inject/store/pump cycles. Concentrations were converted first into water resistivity values Rw, and then into formation resistivity values Rt through Archie's law (1) calibrated on logging data: \\begin{equation} R_{t}=\\frac{a}{\\phi^{m}}R_w where φ is the porosity, and a and m depend on the lithology. Based on this information, the response of downhole electrodes was computed by solving equation (2) (using a finite element modeling code) for electrical surveys conducted at repeated times during the planned ASR cycles, and in particular during the initial ASR testing phase: \\begin{equation} \

  19. Modeling prevalence and counts from most probable number in a bayesian framework: an application to Salmonella typhimurium in fresh pork sausages.

    PubMed

    Gonzales-Barron, Ursula; Redmond, Grainne; Butler, Francis

    2010-08-01

    Prevalence and counts of Salmonella Typhimurium in fresh pork sausage packs at the point of retail were modeled by using Irish and United Kingdom retail surveys' data. A methodology for modeling a second-order distribution for the initial Salmonella concentration (lambda0) in pork sausage at retail was presented considering the uncertainty originated from the most probable-number (MPN) serial dilutions. A conditional probability of observing the tube counts given true Salmonella concentration in a contaminated pack was built from the MPN triplets of every sausage tested. A posterior distribution was then modeled under the assumption that the counts from each of the portions of sausage mix stuffed into casings (and subsequently packed) are Poisson distributed. In order to model the variability of lambda0 among contaminated sausage packs, MPN uncertainties were propagated to a predefined lognormal distribution. Because the sausage samples from the Irish survey were frozen prior to MPN analysis (which is expected to cause reduction in viable cells), the resulting distribution for lambda0 appeared greatly underestimated (mean: 0.514 CFU/g; 95% confidence interval [CI]: 0.02 to 2.74 CFU/g). The lambda0 distribution produced with the United Kingdom survey data (mean: 69.7 CFU/g; 95% CI: 15 to 200 CFU/g) was, however, more conservative, and is to be used along with the fitted distribution for prevalence of Salmonella Typhimurium in pork sausage packs in Ireland (gamma[37.997, 0.0013]; mean: 0.046; 95% CI: 0.032 to 0.064) as the main inputs of a stochastic consumer-phase exposure assessment model.

  20. 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

  1. 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.

  2. Micro Wire-Drawing: Experiments And Modelling

    NASA Astrophysics Data System (ADS)

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

    2007-05-01

    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.

  3. 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.

  4. Modeling of the Edwards pipe experiment

    SciTech Connect

    Tiselj, I.; Petelin, S.

    1995-12-31

    The Edwards pipe experiment is used as one of the basic benchmarks for the two-phase flow codes due to its simple geometry and the wide range of phenomena that it covers. Edwards and O`Brien filled 4-m-long pipe with liquid water at 7 MPa and 502 K and ruptured one end of the tube. They measured pressure and void fraction during the blowdown. Important phenomena observed were pressure rarefaction wave, flashing onset, critical two-phase flow, and void fraction wave. Experimental data were used to analyze the capabilities of the RELAP5/MOD3.1 six-equation two-phase flow model and to examine two different numerical schemes: one from the RELAP5/MOD3.1 code and one from our own code, which was based on characteristic upwind discretization.

  5. 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.

  6. 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

  7. 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…

  8. 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…

  9. Experiment-Driven Modeling of Plasmonic Nanostructures

    NASA Astrophysics Data System (ADS)

    Hryn, Alexander John

    Plasmonic nanostructures can confine light at their surface in the form of surface plasmon polaritons (SPPs) or localized surface plasmons (LSPs) depending on their geometry. SPPs are excited on nano- and micropatterned surfaces, where the typical feature size is on the order of the wavelength of light. LSPs, on the other hand, can be excited on nanoparticles much smaller than the diffraction limit. In both cases, far-field optical measurements are used to infer the excited plasmonic modes, and theoretical models are used to verify those results. Typically, these theoretical models are tailored to match the experimental nanostructures in order to explain observed phenomena. In this thesis, I explore incorporating components of experimental procedures into the models to increase the accuracy of the simulated result, and to inform the design of future experiments. First, I examine SPPs on nanostructured metal films in the form of low-symmetry moire plasmonic crystals. I created a general Bragg model to understand and predict the excited SPP modes in moire plasmonic crystals based on the nanolithography masks used in their fabrication. This model makes use of experimental parameters such as periodicity, azimuthal rotation, and number of sequential exposures to predict the energies of excited SPP modes and the opening of plasmonic band gaps. The model is further expanded to apply to multiscale gratings, which have patterns that contain hierarchical periodicities: a sub-micron primary periodicity, and microscale superperiodicity. A new set of rules was established to determine how superlattice SPPs are excited, and informed development of a new fabrication technique to create superlattices with multiple primary periodicities that absorb light over a wider spectral range than other plasmonic structures. The second half of the thesis is based on development of finite-difference time-domain (FDTD) simulations of plasmonic nanoparticles. I created a new technique to model

  10. 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

    2015-01-26

    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.

  11. 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

  12. Wake Vortex Encounter Model Validation Experiments

    NASA Technical Reports Server (NTRS)

    Vicroy, Dan; Brandon, Jay; Greene, George C.; Rivers, Robert; Shah, Gautam; Stewart, Eric; Stuever, Robert; Rossow, Vernon

    1997-01-01

    The goal of this current research is to establish a database that validate/calibrate wake encounter analysis methods for fleet-wide application; and measure/document atmospheric effects on wake decay. Two kinds of experiments, wind tunnel experiments and flight experiments, are performed. This paper discusses the different types of tests and compares their wake velocity measurement.

  13. 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.

  14. 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.

  15. Braiding DNA: experiments, simulations, and models.

    PubMed

    Charvin, G; Vologodskii, A; Bensimon, D; Croquette, V

    2005-06-01

    DNA encounters topological problems in vivo because of its extended double-helical structure. As a consequence, the semiconservative mechanism of DNA replication leads to the formation of DNA braids or catenanes, which have to be removed for the completion of cell division. To get a better understanding of these structures, we have studied the elastic behavior of two braided nicked DNA molecules using a magnetic trap apparatus. The experimental data let us identify and characterize three regimes of braiding: a slightly twisted regime before the formation of the first crossing, followed by genuine braids which, at large braiding number, buckle to form plectonemes. Two different approaches support and quantify this characterization of the data. First, Monte Carlo (MC) simulations of braided DNAs yield a full description of the molecules' behavior and their buckling transition. Second, modeling the braids as a twisted swing provides a good approximation of the elastic response of the molecules as they are intertwined. Comparisons of the experiments and the MC simulations with this analytical model allow for a measurement of the diameter of the braids and its dependence upon entropic and electrostatic repulsive interactions. The MC simulations allow for an estimate of the effective torsional constant of the braids (at a stretching force F = 2 pN): C(b) approximately 48 nm (as compared with C approximately 100 nm for a single unnicked DNA). Finally, at low salt concentrations and for sufficiently large number of braids, the diameter of the braided molecules is observed to collapse to that of double-stranded DNA. We suggest that this collapse is due to the partial melting and fraying of the two nicked molecules and the subsequent right- or left-handed intertwining of the stretched single strands.

  16. [Neurotheology: neurobiological models of religious experience].

    PubMed

    Passie, T; Warncke, J; Peschel, T; Ott, U

    2013-03-01

    Religions are evolutionary selected social and cultural phenomena. They represent today belief and normative systems on which the main parts of our culture are based. For a long time religions have been seen as mainly originating from a spectrum of religious experiences. These include a broad spectrum of experiences and are astonishingly widespread in the population. The most consistent and transculturally uniform religious experiences are the mystical experiences. Only these (and the prayer experience) have factually been researched in detail neurobiologically. This article presents a review of empirical results and hypothetical approaches to explain mystical religious experiences neurobiologically. Some of the explanatory hypotheses possess logical evidence, some are even supported by neurobiological studies, but all of them have their pitfalls and are at best partially consistent. One important insight from the evidence reviewed here is that there may be a whole array of different neurophysiological conditions which may result in the same core religious mystical experiences.

  17. 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

  18. Irradiation of fresh fish

    NASA Astrophysics Data System (ADS)

    Yueh-jen, Yen; Jin-lai, Zhou; Shao-chun, Lai

    Occasionally, in China, marine products can not be provided for the markets in good quality, for during the time when they are being transported from the sea port to inland towns or even at the time when they are unloaded from the ship, they are beginning to spoil. Obviously, it is very important that appropiate measures should be taken to prevent them from decay. Our study has proved that the shelf life of fresh Flatfish (Cynoglossue robustus) and Silvery pomfret (stromateoides argenteus), which, packed in sealed containers, are irradiated by 1.5 kGy, 2.2 kGy and 3.0 kGy, can be stored for about 13-26 days at 3° - 5° C.

  19. “What Fresh Hell Is This?” Victims of Intimate Partner Violence Describe Their Experiences of Abuse, Pain, and Depression

    PubMed Central

    Cerulli, Catherine; Poleshuck, Ellen; Raimondi, Christina; Veale, Stephanie; Chin, Nancy

    2012-01-01

    Traditionally, professionals working with intimate partner violence (IPV) survivors view a victim through a disciplinary lens, examining health and safety in isolation. Using focus groups with survivors, this study explored the need to address IPV consequences with an integrated model and begin to understand the interconnectedness between violence, health, and safety. Focus group findings revealed that the inscription of pain on the body serves as a reminder of abuse, in turn triggering emotional and psychological pain and disrupting social relationships. In many cases, the physical abuse had stopped but the abuser was relentless by reminding and retraumatizing the victim repeatedly through shared parenting, prolonged court cases, etc. This increased participants’ exhaustion and frustration, making the act of daily living overwhelming. PMID:23226694

  20. Development of a fresh cadaver model for instruction of ultrasound-guided breast biopsy during the surgery clerkship: pre-test and post-test results among third-year medical students.

    PubMed

    McCrary, Hilary C; Krate, Jonida; Savilo, Christine E; Tran, Melissa H; Ho, Hang T; Adamas-Rappaport, William J; Viscusi, Rebecca K

    2016-11-01

    The aim of our study was to determine if a fresh cadaver model is a viable method for teaching ultrasound (US)-guided breast biopsy of palpable breast lesions. Third-year medical students were assessed both preinstruction and postinstruction on their ability to perform US-guided needle aspiration or biopsy of artificially created masses using a 10-item checklist. Forty-one third-year medical students completed the cadaver laboratory as part of the surgery clerkship. Eight items on the checklist were found to be significantly different between pre-testing and post-testing. The mean preinstruction score was 2.4, whereas the mean postinstruction score was 7.10 (P < .001). Fresh cadaver models have been widely used in medical education. However, there are few fresh cadaver models that provide instruction on procedures done in the outpatient setting. Our model was found to be an effective method for the instruction of US-guided breast biopsy among medical students. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. 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.

  2. 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.

  3. 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.

  4. 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…

  5. 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…

  6. Mathematical Modeling: Are Prior Experiences Important?

    ERIC Educational Resources Information Center

    Czocher, Jennifer A.; Moss, Diana L.

    2017-01-01

    Why are math modeling problems the source of such frustration for students and teachers? The conceptual understanding that students have when engaging with a math modeling problem varies greatly. They need opportunities to make their own assumptions and design the mathematics to fit these assumptions (CCSSI 2010). Making these assumptions is part…

  7. 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.

  8. 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

  9. Model Experiment of Two-Dimentional Brownian Motion by Microcomputer.

    ERIC Educational Resources Information Center

    Mishima, Nobuhiko; And Others

    1980-01-01

    Describes the use of a microcomputer in studying a model experiment (Brownian particles colliding with thermal particles). A flow chart and program for the experiment are provided. Suggests that this experiment may foster a deepened understanding through mutual dialog between the student and computer. (SK)

  10. Fundamental efficiency of nanothermophones: modeling and experiments.

    PubMed

    Vesterinen, V; Niskanen, A O; Hassel, J; Helistö, P

    2010-12-08

    Scaling down the dimensions of thermoacoustic sound sources (thermophones) improves efficiency by means of reducing speaker heat capacity. Recent experiments with nanoscale thermophones have revealed properties which are not fully understood theoretically. We develop a Green's function formalism which quantitatively explains some observed discrepancies, e.g., the effect of a heat-absorbing substrate in the proximity of the sound source. We also find a generic ultimate limit for thermophone efficiency. We verify the theory with experiments and finite difference method simulations which deal with thermoacoustically operated suspended arrays of nanowires. The efficiency of our devices is measured to be 1 order of magnitude below the ultimate bound. At low frequencies this mainly results from the presence of a substrate. At high frequencies, on the other hand, the efficiency is limited by the heat capacity of the nanowires. Measured sound pressure level and efficiency are in good agreement with simulations. We discuss the feasibility of reaching the ultimate limit in practice.

  11. Vortex microscope: analytical model and experiment

    NASA Astrophysics Data System (ADS)

    Masajada, Jan; Popiołek-Masajada, Agnieszka; Szatkowski, Mateusz; Plociniczak, Łukasz

    2015-11-01

    We present the analytical model describing the Gaussian beam propagation through the off axis vortex lens and the set of axially positioned ideal lenses. The model is derived on the base of Fresnel diffraction integral. The model is extended to the case of vortex lens with any topological charge m. We have shown that the Gaussian beam propagation can be represented by function G which depends on four coefficients. When propagating from one lens to another the function holds its form but the coefficient changes.

  12. Annual modulation experiments, galactic models and WIMPs

    NASA Astrophysics Data System (ADS)

    Hudson, Robert G.

    Our task in the paper is to examine some recent experiments (in the period 1996-2002) bearing on the issue of whether there is dark matter in the universe in the form of neutralino WIMPs (weakly interacting massive particles). Our main focus is an experiment performed by the DAMA group that claims to have found an 'annual modulation signature' for the WIMP. DAMA's result has been hotly contested by two other groups, EDELWEISS and CDMS, and we study the details of the experiments performed by all three groups. Our goal is to investigate the philosophic and sociological implications of this controversy. Particularly, using an innovative theoretical strategy suggested by (Copi, C. and L. M. Krauss (2003). Comparing interaction rate detectors for weakly interacting massive particles with annual modulation detectors. Physical Review D, 67, 103 507), we suggest a new way of resolving discordant experimental data (extending a previous analysis by (Franklin, A. (2002). Selectivity and discord. Pittsburgh: University of Pittsburgh Press). In addition, we are in a position to contribute substantively to the debate between realists and constructive empiricists. Finally, from a sociological standpoint, we remark that DAMA's work has been valuable in mobilizing other research teams and providing them with a critical focus.

  13. 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.

  14. 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.

  15. 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.

  16. Modeling of modification experiments involving neutral-gas release

    SciTech Connect

    Bernhardt, P.A.

    1983-01-01

    Many experiments involve the injection of neutral gases into the upper atmosphere. Examples are critical velocity experiments, MHD wave generation, ionospheric hole production, plasma striation formation, and ion tracing. Many of these experiments are discussed in other sessions of the Active Experiments Conference. This paper limits its discussion to: (1) the modeling of the neutral gas dynamics after injection, (2) subsequent formation of ionosphere holes, and (3) use of such holes as experimental tools.

  17. Modelling the effect of temperature, water activity and carbon dioxide on the growth of Aspergillus niger and Alternaria alternata isolated from fresh date fruit.

    PubMed

    Belbahi, A; Leguerinel, I; Méot, J-M; Loiseau, G; Madani, K; Bohuon, P

    2016-12-01

    To quantify and model the combined effects of temperature (T) (10-40°C), water activity (aw ) (0·993-0·818) and CO2 concentration (9·4-55·1%, v/v) on the growth rate of Aspergillus niger and Alternaria alternata that cause spoilage during the storage and packaging of dates. The effects of environmental factors were studied using the γ-concept. Cardinal models were used to quantify the effect of studied environmental factors on the growth rates. Firstly, the cardinal parameters were estimated independently from experiments carried out on potato dextrose agar using a monofactorial design. Secondly, model performance evaluation was conducted on pasteurized date paste. The boundary between growth and no-growth was predicted using a deterministic approach. Aspergillus niger displayed a faster growth rate and higher tolerance to low aw than Al. alternata, which in turn proved more resistant to CO2 concentration. Minimal cardinal parameters of T and aw were lower than those reported in the literature. The combination of the aw and CO2 effects significantly affected As. niger and Al. alternata growth. The γ-concept model overestimated growth rates, however, it is optimistic and provides somewhat conservative predictions. The developed model provides a decision support tool for the choice of the date fruit conservation mode (refrigeration, drying, modified atmospheric packaging or their combination) using T, aw and CO2 as environmental factors. © 2016 The Society for Applied Microbiology.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Reverse osmosis desalination: Modeling and experiment

    NASA Astrophysics Data System (ADS)

    Fraidenraich, Naum; Vilela, Olga C.; Lima, Gilmário A.; Gordon, Jeffrey M.

    2009-03-01

    An analytic model for the performance of reverse osmosis desalination systems is derived. Predictions are shown to agree well with extensive measurements conducted on a commercial multistage reverse osmosis desalination unit over a broad range of operating conditions. The model allows a transparent understanding of the dependence of system performance on key design and operating variables. Identifying the characteristic flow rate and length scale of reverse osmosis systems allows a universal description of the variation of the permeate flow rate and recovery factor with the salinity, flow rate, and pressure of the feedwater.

  3. Model localization experiments on a ribbed antenna

    NASA Technical Reports Server (NTRS)

    Levine-West, M. B.; Salama, M. A.

    1992-01-01

    In this paper, the model localization (ML) phenomenon is investigated experimentally and analytically to determine the influence of its parameters. For this purpose, a full-scale 12-rib loosely-coupled antenna testbed with small imperfections is dynamically tested for various levels of inter-rib coupling stiffness and excitation force. The experimental results are described herein. Using a simplified numerical model of the structure, a sensitivity analysis of the modal behavior is also performed. The numerical and experimental results are shown to agree remarkably well, thereby providing conclusive validation of the ML phenomenon on a testbed having the dynamic characteristics of space structures.

  4. 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.

  5. [Experience of implementing a primary attention model].

    PubMed

    Ruiz-Rodríguez, Myriam; Acosta-Ramírez, Naydú; Rodríguez Villamizar, Laura A; Uribe, Luz M; León-Franco, Martha

    2011-12-01

    Identifying barriers and dynamic factors in setting up a primary health care (PHC) model in the Santander department during the last decade. This was a qualitative study, focusing on pluralism and triangulating sources and actors, with a critical analysis of limits and judgments values (boundary critique). Philosophical/conceptual and operational management problems were found from the emergent categories related to appropriating PHC attributes. The theoretical model design was in fact not developed in practice. The PHC strategy is selective and state-led (at department level), focusing on rural interventions developed by nursing assistants and orientated towards fulfilling public health goals in the first healthcare level. Difficulties at national, state and local level were identified which could be useful in other national and international contexts. Structural healthcare system market barriers were the most important constraints since the model operates through the contractual logic of institutional segmentation and operational fragmentation. Human resource management focusing on skills, suitable local health management and systematic evaluation studies would thus be suggested as essential operational elements for facing the aforementioned problems and encourage an integral PHC model in Colombia.

  6. Plasma gun pellet acceleration modeling and experiment

    SciTech Connect

    Kincaid, R.W.; Bourham, M.A.; Gilligan, J.G.

    1996-12-31

    Modifications to the electrothermal plasma gun SIRENS have been completed to allow for acceleration experiments using plastic pellets. Modifications have been implemented to the 1-D, time dependent code ODIN to include pellet friction, momentum, and kinetic energy with options of variable barrel length. The code results in the new version, POSEIDON, compare favorably with experimental data and with code results from ODIN. Predicted values show an increased pellet velocity along the barrel length, achieving 2 km/s exit velocity. Measured velocity, at three locations along the barrel length, showed good correlation with predicted values. The code has also been used to investigate the effectiveness of longer pulse length on pellet velocity using simulated ramp up and down currents with flat top, and triangular current pulses with early and late peaking. 16 refs., 5 figs.

  7. Model experiments of laser-triggered lightning

    SciTech Connect

    Shindo, Takatoshi; Aihara, Yoshinori; Miki, Megumu; Suzuki, Toshio )

    1993-01-01

    Experiments to guide electric discharges with a chain of apparently discrete air-breakdown plasmas (plasma channel) produced by a laser were carried out. The electric discharge was guided up to 2m with a high power CO[sub 2] laser focused by a 10-m focal length mirror. Voltage was applied at selected delay times [tau] following laser radiation. The relations between 50% flashover voltage of a gap filled with laser-produced plasmas and delay times [tau], between the guided length and the peak of the applied voltage, were obtained experimentally. The effects of the polarity of an applied voltage and the position of the plasma channel on flashover voltage are described. Development characteristics of the guided discharge were also investigated.

  8. Model experiments of superlubricity of graphite

    NASA Astrophysics Data System (ADS)

    Dienwiebel, Martin; Pradeep, Namboodiri; Verhoeven, Gertjan S.; Zandbergen, Henny W.; Frenken, Joost W. M.

    2005-02-01

    Graphite is known to be a good solid lubricant. The low-friction behavior is traditionally ascribed to the low resistance to shear. We have recently observed that the ultra-low friction found in friction force microscopy experiments on graphite is due to a effect called superlubricity [M. Dienwiebel, G. S. Verhoeven, N. Pradeep, J.W.M. Frenken, J.A. Heimberg, H.W. Zandbergen, Phys. Rev. Lett. 92 (2004) 126101]. Here, we provide additional experimental evidence that superlubricity has been taken place between a small graphite flake attached to the scanning tip and the graphite surface. Finally, we speculate about the significance of this for the lubricating properties of graphite.

  9. High precision modeling for fundamental physics experiments

    NASA Astrophysics Data System (ADS)

    Rievers, Benny; Nesemann, Leo; Costea, Adrian; Andres, Michael; Stephan, Ernst P.; Laemmerzahl, Claus

    With growing experimental accuracies and high precision requirements for fundamental physics space missions the needs for accurate numerical modeling techniques are increasing. Motivated by the challenge of length stability in cavities and optical resonators we propose the develop-ment of a high precision modeling tool for the simulation of thermomechanical effects up to a numerical precision of 10-20 . Exemplary calculations for simplified test cases demonstrate the general feasibility of high precision calculations and point out the high complexity of the task. A tool for high precision analysis of complex geometries will have to use new data types, advanced FE solver routines and implement new methods for the evaluation of numerical precision.

  10. 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).

  11. 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.

  12. 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 ...

  13. Differential equation modeling of HIV viral fitness experiments: model identification, model selection, and multimodel inference.

    PubMed

    Miao, Hongyu; Dykes, Carrie; Demeter, Lisa M; Wu, Hulin

    2009-03-01

    Many biological processes and systems can be described by a set of differential equation (DE) models. However, literature in statistical inference for DE models is very sparse. We propose statistical estimation, model selection, and multimodel averaging methods for HIV viral fitness experiments in vitro that can be described by a set of nonlinear ordinary differential equations (ODE). The parameter identifiability of the ODE models is also addressed. We apply the proposed methods and techniques to experimental data of viral fitness for HIV-1 mutant 103N. We expect that the proposed modeling and inference approaches for the DE models can be widely used for a variety of biomedical studies.

  14. 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…

  15. 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…

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Characterizing nanoparticle interactions: Linking models to experiments

    SciTech Connect

    Ramakrishnan, S.; Zukoski, C. F.

    2000-07-15

    Self-assembly of nanoparticles involves manipulating particle interactions such that attractions are on the order of the average thermal energy in the system. If the self-assembly is to result in an ordered packing, an understanding of their phase behavior is necessary. Here we test the ability of simple pair potentials to characterize the interactions and phase behavior of silico tungstic acid (STA), a 1.2 nm particle. The strength of interaction is controlled by dispersing STA in different background salt concentrations. The experimental variables used in characterizing the interactions are the osmotic compressibility (d{pi}/d{rho}), the second virial coefficient (B{sub 2}), relative solution viscosity ({eta}/{eta}{sub c}), and the solubility ({rho}{sigma}{sup 3}){sub sat}. Various techniques are then developed to extract the parameters of square well, the adhesive hard sphere (AHS), and the Yukawa pair potentials that best describe the experimental data. The AHS model describes the solution thermodynamic behavior only where the system is weakly attractive but, as would be expected, fails when long range repulsions or nonmonotonic pair potentials become important. Model free representations are presented which offer the opportunity to extract pair potential parameters. (c) 2000 American Institute of Physics.

  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. MHD Models and Laboratory Experiments of Jets

    NASA Astrophysics Data System (ADS)

    Gardiner, T. A.; Frank, A.; Blackman, E. G.; Lebedev, S. V.; Chittenden, J. P.; Ampleford, D.; Bland, S. N.; Ciardi, A.; Sherlock, M.; Haines, M. G.

    Jet research has long relied upon a combination of analytical, observational and numerical studies to elucidate the complex phenomena involved. One element missing from these studies (which other physical sciences utilize) is the controlled experimental investigation of such systems. With the advent of high-power lasers and fast Z-pinch machines it is now possible to experimentally study similar systems in a laboratory setting. Such investigations can contribute in two useful ways. They can be used for comparison with numerical simulations as a means to validate simulation codes. More importantly, however, such investigations can also be used to complement other jet research, leading to fundamentally new knowledge. In the first part of this article, we analyze the evolution of magnetized wide-angle winds in a collapsing environment. We track the ambient and wind mass separately and describe a physical mechanism by which an ionized central wind can entrain the ambient gas giving rise to internal shells of molecular material on short time scales. The formation of internal shells in molecular outflows has been found to be an important ingredient in describing the observations of convex spurs in P-V diagrams (Hubble wedges in M-V diagrams). In the second part, we present astrophysically relevant experiments in which supersonic jets are created using a conical wire array Z-pinch. The conically convergent flow generates a standing shock around the axis which collimates the flow into a Mach ~ 30 jet. The jet formation process is closely related to the work of Cantó et al. (1988) for hydrodynamic jet collimation. The influence of radiative cooling on collimation and stability is studied by varying the wire material (Al, Fe, and W).

  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. Integration of User Profiles: Models and Experiments in Information Retrieval.

    ERIC Educational Resources Information Center

    Myaeng, Sung H.; Korfhage, Robert R.

    1990-01-01

    Discussion of the interpretation of user queries in information retrieval highlights theoretical models that utilize user characteristics maintained in the form of a user profile. Various query/profile interaction models are identified, and an experiment is described that tested the relevance of retrieved documents based on various models. (29…

  6. "ABC's Earthquake" (Experiments and models in seismology)

    NASA Astrophysics Data System (ADS)

    Almeida, Ana

    2017-04-01

    Ana Almeida, Portugal Almeida, Ana Escola Básica e Secundária Dr. Vieira de Carvalho Moreira da Maia, Portugal The purpose of this presentation, in poster format, is to disclose an activity which was planned and made by me, in a school on the north of Portugal, using a kit of materials simple and easy to use - the sismo-box. The activity "ABC's Earthquake" was developed under the discipline of Natural Sciences, with students from 7th grade, geosciences teachers and other areas. The possibility of work with the sismo-box was seen as an exciting and promising opportunity to promote science, seismology more specifically, to do science, when using the existing models in the box and with them implement the scientific method, to work and consolidate content and skills in the area of Natural Sciences, to have a time of sharing these materials with classmates, and also with other teachers from the different areas. Throughout the development of the activity, either with students or teachers, it was possible to see the admiration by the models presented in the earthquake-box, as well as, the interest and the enthusiasm in wanting to move and understand what the results after the proposed procedure in the script. With this activity, we managed to promote: - educational success in this subject; a "school culture" with active participation, with quality, rules, discipline and citizenship values; fully integration of students with special educational needs; strengthen the performance of the school as a cultural, informational and formation institution; provide activities to date and innovative; foment knowledge "to be, being and doing" and contribute to a moment of joy and discovery.Learn by doing!

  7. 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

  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. Laboratory modeling of ionospheric heating experiments

    NASA Astrophysics Data System (ADS)

    Starodubtsev, M. V.; Nazarov, V. V.; Gushchin, M. E.; Kostrov, A. V.

    2016-10-01

    Turbulent plasma processes, such as those which occur in the Earth's ionosphere during ionospheric heating by powerful radio waves, were studied under laboratory conditions, and new physical models of small-scale ionospheric turbulence are proposed as a result of these studies. It is shown here that the mechanism of small-scale plasma filamentation can be connected with the thermal self-channeling of Langmuir waves. During this process, Langmuir waves are guided by a plasma channel, which in turn is formed by the guided waves through a thermal plasma nonlinearity. The spectrum of the self-guided Langmuir waves exhibits sidebands whose features are similar to stimulated electromagnetic emission. We present two mechanisms of sideband generation. The first mechanism can be observed during the formation of the plasma channel and is connected with the parametric shift in the frequency of the self-channeling wave. The second mechanism is connected with the scattering of the self-channeling wave on the low-frequency eigenmodes of the plasma irregularity.

  10. 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

  11. Optimal experiment design for model selection in biochemical networks

    PubMed Central

    2014-01-01

    Background Mathematical modeling is often used to formalize hypotheses on how a biochemical network operates by discriminating between competing models. Bayesian model selection offers a way to determine the amount of evidence that data provides to support one model over the other while favoring simple models. In practice, the amount of experimental data is often insufficient to make a clear distinction between competing models. Often one would like to perform a new experiment which would discriminate between competing hypotheses. Results We developed a novel method to perform Optimal Experiment Design to predict which experiments would most effectively allow model selection. A Bayesian approach is applied to infer model parameter distributions. These distributions are sampled and used to simulate from multivariate predictive densities. The method is based on a k-Nearest Neighbor estimate of the Jensen Shannon divergence between the multivariate predictive densities of competing models. Conclusions We show that the method successfully uses predictive differences to enable model selection by applying it to several test cases. Because the design criterion is based on predictive distributions, which can be computed for a wide range of model quantities, the approach is very flexible. The method reveals specific combinations of experiments which improve discriminability even in cases where data is scarce. The proposed approach can be used in conjunction with existing Bayesian methodologies where (approximate) posteriors have been determined, making use of relations that exist within the inferred posteriors. PMID:24555498

  12. 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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. 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.

  14. The Aqueous Alteration of CR Chondrites: Experiments and Geochemical Modeling

    NASA Astrophysics Data System (ADS)

    Perronnet, M.; Berger, G.; Zolensky, M. E.; Toplis, M. J.; Kolb, V. M.; Bajagic, M.

    2007-03-01

    Laboratory alteration experiments were performed on mineralogical assemblages having the unaltered CR composition. The mineralogy of reaction products was compared to that of Renazzo and GRO 95577 and to predictions of geochemical modeling.

  15. 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.

  16. 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.

  17. Naturalness, privacy, and restorative experiences in wilderness: An integrative model

    Treesearch

    William E. Hammitt

    2012-01-01

    It is suggested that the wilderness experience is a restorative experience that results from the interconnectivity between naturalness/ remoteness and privacy/unconfinement and the four components essential for an environment to be restorative. A model-framework is offered to illustrate the linkages among the environmental, social, and restoration components of...

  18. 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.

  19. Granular Medium Impacted by a Projectile: Experiment and Model

    NASA Astrophysics Data System (ADS)

    Crassous, J.; Valance, A.

    2009-06-01

    We present an experiment and a simple model of a granular projectile on a granular medium. Experiment consists in impacting an half space of PVC beads with a single bead. Numerous beads are then ejected around the impact point. The loci of ejection and velocities of the ejecta were measured. The experimental data were compared with the predictions of a simple discrete model. In this model, the energy is transferred from grain to grain on a frozen disordered medium following the law of binary collisions. This theoretical description is in remarkable agreement with the experimental observations. Besides, the present model provides a clear picture of the mechanism of energy propagation.

  20. 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.

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

    PubMed

    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.

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

    PubMed Central

    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

    Abstract 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. PMID:27818853

  3. 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.

  4. Limited Resuscitation With Fresh or Stored Whole Blood Corrects Cardiovascular and Metabolic Function in a Rat Model of Polytrauma and Hemorrhage.

    PubMed

    Chen, Jacob; Wu, Xiaowu; Keesee, Jeffrey; Liu, Bin; Darlington, Daniel N; Cap, Andrew P

    2017-02-01

    We have recently shown that human whole blood stored at 4°C maintains hemostatic and platelet function. In this study, we compared restoration of hemodynamic, metabolic and hemostatic function after limited resuscitation with rat fresh whole blood, rat stored whole blood, or Lactated Ringers in traumatized rats. Rat whole blood was stored for 10 days at 4°C for evaluation of hemostatic function. Polytrauma was performed on isoflurane-anesthetized Sprague-Dawley rats (350-450 g) by damage to the intestines, liver, right leg skeletal muscle, and right femur fracture, followed by 40% hemorrhage. At 1 h, rats were resuscitated (20%) with either fresh whole blood (FWB), stored whole blood, 4°C for 7 days (SWB), Lactated Ringers (LR), or nothing. Blood samples were taken before and 2 h after trauma and hemorrhage to evaluate metabolic and hemostatic function. Whole blood stored for 10 days showed a significant prolongation in prothrombin time (PT) and activated partial thromboplastin time (aPTT), and fall in fibrinogen concentration, but no change in Maximum Clot Firmness or speed of clot formation. Platelet function was maintained until day 7 in storage, than fell significantly. Polytrauma and hemorrhage in rats led to a fall in arterial pressure, plasma bicarbonate, fibrinogen, and platelet function, and a rise in plasma lactate, PT, aPTT, and creatinine. Resuscitation with either FWB or 7 day SWB, but not LR, returned arterial pressure, plasma lactate and plasma bicarbonate to levels similar to control, but had no effect on the fall in fibrinogen or platelet function, or the rise in PT, aPTT, or creatinine. Hemostatic and platelet function of rat whole blood stored at 4°C is preserved for at least 7 days in vitro. Low volume resuscitation with SWB or FWB, but not LR, restores hemodynamic and metabolic function, but not the coagulopathy after severe trauma and hemorrhage.

  5. Model validation for karst flow using sandbox experiments

    NASA Astrophysics Data System (ADS)

    Ye, M.; Pacheco Castro, R. B.; Tao, X.; Zhao, J.

    2015-12-01

    The study of flow in karst is complex due of the high heterogeneity of the porous media. Several approaches have been proposed in the literature to study overcome the natural complexity of karst. Some of those methods are the single continuum, double continuum and the discrete network of conduits coupled with the single continuum. Several mathematical and computing models are available in the literature for each approach. In this study one computer model has been selected for each category to validate its usefulness to model flow in karst using a sandbox experiment. The models chosen are: Modflow 2005, Modflow CFPV1 and Modflow CFPV2. A sandbox experiment was implemented in such way that all the parameters required for each model can be measured. The sandbox experiment was repeated several times under different conditions. The model validation will be carried out by comparing the results of the model simulation and the real data. This model validation will allows ud to compare the accuracy of each model and the applicability in Karst. Also we will be able to evaluate if the results of the complex models improve a lot compared to the simple models specially because some models require complex parameters that are difficult to measure in the real world.

  6. 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

  7. 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.

  8. 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.

  9. Evaluation of experiments for estimation of dynamical crop model parameters.

    PubMed

    Ioslovich, Ilya; Gutman, Per-Olof

    2007-07-01

    Planned experiments are usually expected to provide maximal benefits within limited costs. However, there are known difficulties in optimal design of experiments. They are related to the case when only limited number of parameters could be estimated, because available experiments are noninformative. The useful method for this case is considered based on the dominant parameters selection procedure (DPS). The methodology is illustrated here with data from five planned experiments related to the NICOLET lettuce growth model. The maximal number and the list of estimated parameters are determined while the conditional number of the information Fisher matrix (modified E-criterion) is kept below a given upper constraint.

  10. Design of experiments to investigate dynamic cell signaling models.

    PubMed

    Bandara, Samuel; Meyer, Tobias

    2012-01-01

    This chapter describes approaches to make use of dynamic models of cell signaling systems in order to optimize experiments in cell biology. We are particularly focusing on the question of how small molecule inhibitors or activators can best be used to get the most information out of a limited number of experiments when only a handful of molecular species can be measured. One goal addressed by this chapter is to find time course experiments to discriminate between rivaling molecular mechanisms. The other goal is to find experiments that are useful for inferring rate constants, binding affinities, concentrations, and other model parameters from time course data. Both are treated as optimal control problems in which rapid pharmacological perturbation schemes are identified in silico in order to close an experimental cycle from modeling back to the laboratory bench.

  11. Dynamic modelling and analysis of biochemical networks: mechanism-based models and model-based experiments.

    PubMed

    van Riel, Natal A W

    2006-12-01

    Systems biology applies quantitative, mechanistic modelling to study genetic networks, signal transduction pathways and metabolic networks. Mathematical models of biochemical networks can look very different. An important reason is that the purpose and application of a model are essential for the selection of the best mathematical framework. Fundamental aspects of selecting an appropriate modelling framework and a strategy for model building are discussed. Concepts and methods from system and control theory provide a sound basis for the further development of improved and dedicated computational tools for systems biology. Identification of the network components and rate constants that are most critical to the output behaviour of the system is one of the major problems raised in systems biology. Current approaches and methods of parameter sensitivity analysis and parameter estimation are reviewed. It is shown how these methods can be applied in the design of model-based experiments which iteratively yield models that are decreasingly wrong and increasingly gain predictive power.

  12. Model of CSR Induced Bursts in Slicing Experiments

    SciTech Connect

    Stupakov, G.; Heifets, S.; /SLAC

    2006-05-16

    We suggest a model describing the CSR bursts observed in recent experiments at the Advanced Light Source at the LBL. The model is based on the linear theory of the CSR instability in electron rings. We describe how an initial perturbation of the beam generated by the laser pulse evolves in time when the beam is unstable due to the CSR wakefield.

  13. Enthalpy benchmark experiments for numerical ice sheet models

    NASA Astrophysics Data System (ADS)

    Kleiner, T.; Rückamp, M.; Bondzio, J. H.; Humbert, A.

    2015-02-01

    We present benchmark experiments to test the implementation of enthalpy and the corresponding boundary conditions in numerical ice sheet models. Since we impose several assumptions on the experiment design, analytical solutions can be formulated for the proposed numerical experiments. The first experiment tests the functionality of the boundary condition scheme and the basal melt rate calculation during transient simulations. The second experiment addresses the steady-state enthalpy profile and the resulting position of the cold-temperate transition surface (CTS). For both experiments we assume ice flow in a parallel-sided slab decoupled from the thermal regime. We compare simulation results achieved by three different ice flow-models with these analytical solutions. The models agree well to the analytical solutions, if the change in conductivity between cold and temperate ice is properly considered in the model. In particular, the enthalpy gradient on the cold side of the CTS goes to zero in the limit of vanishing temperate-ice conductivity, as required from the physical jump conditions at the CTS.

  14. 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.

  15. 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... 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. 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.

  17. 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.

  18. Designing Experiments to Discriminate Families of Logic Models

    PubMed Central

    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

  19. 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.

  20. Neutral null models for diversity in serial transfer evolution experiments.

    PubMed

    Harpak, Arbel; Sella, Guy

    2014-09-01

    Evolution experiments with microorganisms coupled with genome-wide sequencing now allow for the systematic study of population genetic processes under a wide range of conditions. In learning about these processes in natural, sexual populations, neutral models that describe the behavior of diversity and divergence summaries have played a pivotal role. It is therefore natural to ask whether neutral models, suitably modified, could be useful in the context of evolution experiments. Here, we introduce coalescent models for polymorphism and divergence under the most common experimental evolution assay, a serial transfer experiment. This relatively simple setting allows us to address several issues that could affect diversity patterns in evolution experiments, whether selection is operating or not: the transient behavior of neutral polymorphism in an experiment beginning from a single clone, the effects of randomness in the timing of cell division and noisiness in population size in the dilution stage. In our analyses and discussion, we emphasize the implications for experiments aimed at measuring diversity patterns and making inferences about population genetic processes based on these measurements.

  1. 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.

  2. Harmonic Oscillator Model for Radin's Markov-Chain Experiments

    NASA Astrophysics Data System (ADS)

    Sheehan, D. P.; Wright, J. H.

    2006-10-01

    The conscious observer stands as a central figure in the measurement problem of quantum mechanics. Recent experiments by Radin involving linear Markov chains driven by random number generators illuminate the role and temporal dynamics of observers interacting with quantum mechanically labile systems. In this paper a Lagrangian interpretation of these experiments indicates that the evolution of Markov chain probabilities can be modeled as damped harmonic oscillators. The results are best interpreted in terms of symmetric equicausal determinism rather than strict retrocausation, as posited by Radin. Based on the present analysis, suggestions are made for more advanced experiments.

  3. Harmonic Oscillator Model for Radin's Markov-Chain Experiments

    SciTech Connect

    Sheehan, D. P.; Wright, J. H.

    2006-10-16

    The conscious observer stands as a central figure in the measurement problem of quantum mechanics. Recent experiments by Radin involving linear Markov chains driven by random number generators illuminate the role and temporal dynamics of observers interacting with quantum mechanically labile systems. In this paper a Lagrangian interpretation of these experiments indicates that the evolution of Markov chain probabilities can be modeled as damped harmonic oscillators. The results are best interpreted in terms of symmetric equicausal determinism rather than strict retrocausation, as posited by Radin. Based on the present analysis, suggestions are made for more advanced experiments.

  4. Astronaut Robert Crippen holds training model of Skylab experiment

    NASA Image and Video Library

    1972-06-15

    S72-43280 (15 June 1972) --- Astronaut Robert L. Crippen, Skylab Medical Experiment Altitude Test (SMEAT) commander, holds the training model of Skylab experiment T003, the aerosol analysis test, in this preview of SMEAT activity. He is part of a three-man SMEAT crew who will spend up to 56 days in the Crew Systems Division's 20-foot altitude chamber at the NASA Manned Spacecraft Center (MSC) beginning in mid-July to obtain medical data and evaluate medical experiment equipment for Skylab. The two crew members not shown in this view are astronauts Karol J. Bobko, SMEAT pilot, and Dr. William E. Thornton, SMEAT science pilot. Photo credit: NASA

  5. Cellular Shape Memory Alloy Structures: Experiments & Modeling (Part 1)

    DTIC Science & Technology

    2012-08-01

    AFOSR  Grant  #FA9550-­‐08-­‐1-­‐0313 Cellular  Shape  Memory   Alloy  Structures:   Experiments  &  Modeling J.  Shaw  (UM...2012 4. TITLE AND SUBTITLE Cellular Shape Memory Alloy Structures: Experiments & Modeling (Part 1) 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c...dense,  0.37  g/cc) Combine benefits of light-weight cellular structures with Shape Memory Alloy (SMA) adaptive behavior CombinaKon •Amplified

  6. Energy response model of the Daya Bay experiment

    NASA Astrophysics Data System (ADS)

    Viaux, Nicolás; Daya Bay Collaboration

    2017-09-01

    The Daya Bay reactor neutrino experiment has made the most precise measurement of neutrino oscillation parameter sin2 2θ 13 as well as the first direct measurement of effective mass-squared difference |Δ {m}ee2| through the analyses of reactor antineutrino rate and spectral shape. Precise measurements of reactor antineutrino spectrum require an accurate understanding of the detector energy response. We developed an energy response model of the antineutrino detector using various in-situ calibrations and external measurements. The poster will present details of the energy response model that is used in the latest results from the Daya Bay experiment.

  7. Data Assimilation and Model Evaluation Experiments - North Atlantic Basin; Preliminary Experiment Plan.

    DTIC Science & Technology

    1994-12-01

    and will be allowed to evolve as the experiment proceeds. A brief description by participants of models and data assimilation methods are included....describes the approach to implement a comparative environment in which to assess numerical ocean model nowcast/forecast capabilities and data assimilation ... methods and techniques. Goals are stated which provide direction for the long term, the next five years, and specifically for the next two years. A

  8. 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.

  9. 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

  10. Neural Network Models of Learning and Categorization in Multigame Experiments

    PubMed Central

    Marchiori, Davide; Warglien, Massimo

    2011-01-01

    Previous research has shown that regret-driven neural networks predict behavior in repeated completely mixed games remarkably well, substantially equating the performance of the most accurate established models of learning. This result prompts the question of what is the added value of modeling learning through neural networks. We submit that this modeling approach allows for models that are able to distinguish among and respond differently to different payoff structures. Moreover, the process of categorization of a game is implicitly carried out by these models, thus without the need of any external explicit theory of similarity between games. To validate our claims, we designed and ran two multigame experiments in which subjects faced, in random sequence, different instances of two completely mixed 2 × 2 games. Then, we tested on our experimental data two regret-driven neural network models, and compared their performance with that of other established models of learning and Nash equilibrium. PMID:22207832

  11. Modeling of detachment experiments at DIII-D

    DOE PAGES

    Canik, John M.; Briesemeister, Alexis R.; Lasnier, C. J.; ...

    2014-11-26

    Edge fluid–plasma/kinetic–neutral modeling of well-diagnosed DIII-D experiments is performed in order to document in detail how well certain aspects of experimental measurements are reproduced within the model as the transition to detachment is approached. Results indicate, that at high densities near detachment onset, the poloidal temperature profile produced in the simulations agrees well with that measured in experiment. However, matching the heat flux in the model requires a significant increase in the radiated power compared to what is predicted using standard chemical sputtering rates. Lastly, these results suggest that the model is adequate to predict the divertor temperature, provided thatmore » the discrepancy in radiated power level can be resolved.« less

  12. Modeling of detachment experiments at DIII-D

    SciTech Connect

    Canik, John M.; Briesemeister, Alexis R.; Lasnier, C. J.; Leonard, A. W.; Lore, J. D.; McLean, A. G.; Watkins, J. G.

    2014-11-26

    Edge fluid–plasma/kinetic–neutral modeling of well-diagnosed DIII-D experiments is performed in order to document in detail how well certain aspects of experimental measurements are reproduced within the model as the transition to detachment is approached. Results indicate, that at high densities near detachment onset, the poloidal temperature profile produced in the simulations agrees well with that measured in experiment. However, matching the heat flux in the model requires a significant increase in the radiated power compared to what is predicted using standard chemical sputtering rates. Lastly, these results suggest that the model is adequate to predict the divertor temperature, provided that the discrepancy in radiated power level can be resolved.

  13. Mathematical modeling of isotope labeling experiments for metabolic flux analysis.

    PubMed

    Nargund, Shilpa; Sriram, Ganesh

    2014-01-01

    Isotope labeling experiments (ILEs) offer a powerful methodology to perform metabolic flux analysis. However, the task of interpreting data from these experiments to evaluate flux values requires significant mathematical modeling skills. Toward this, this chapter provides background information and examples to enable the reader to (1) model metabolic networks, (2) simulate ILEs, and (3) understand the optimization and statistical methods commonly used for flux evaluation. A compartmentalized model of plant glycolysis and pentose phosphate pathway illustrates the reconstruction of a typical metabolic network, whereas a simpler example network illustrates the underlying metabolite and isotopomer balancing techniques. We also discuss the salient features of commonly used flux estimation software 13CFLUX2, Metran, NMR2Flux+, FiatFlux, and OpenFLUX. Furthermore, we briefly discuss methods to improve flux estimates. A graphical checklist at the end of the chapter provides a reader a quick reference to the mathematical modeling concepts and resources.

  14. Analysis of the Student Experience in an Attending Pharmacist Model General Medicine Advanced Pharmacy Practice Experience

    PubMed Central

    Lau, Carmen; Sy, Erin; Moogk, Hana; Weber, Stanley S.; Danielson, Jennifer

    2017-01-01

    Objective. To characterize and determine the quality of the student experience in an attending pharmacist model (APM). Methods. In-depth interviews were conducted with students completing an advanced pharmacy practice experience (APPE) at two general medicine services using the APM over a 2-year time period. Quantitative information about student learning and interprofessional interactions were extracted from student evaluations of the site. Data from the mixed model were analyzed to identify strengths of the APM and areas needing improvement. Results. Strengths of the APM included positive student interaction with the pharmacy resident and more students reporting full integration in and accountability to the interprofessional team for patient outcomes compared to students in non-teaching models. A few students at one site reported a need for greater delineation of expectations, more initial support from preceptors, and initial responsibility for fewer patients. These factors were modified before the second APM year and subsequent reports from students at this site were uniformly positive. Students at the second site did not note areas needing improvement. The APM increased student capacity at both sites. Conclusion. The attending pharmacist model provided a high quality learning experience for students, particularly with regard to integration into and accountability for patient outcomes to the interprofessional team. Qualitative research methods enabled precise detection of areas needing improvement at one site and confirmed that changes made at that site improved the student experience. PMID:28630507

  15. Corneal hyper-viscoelastic model: derivations, experiments, and simulations.

    PubMed

    Su, Peng; Yang, Yang; Xiao, Jingjing; Song, Yanming

    2015-01-01

    The aim of this study is to propose a method to construct corneal biomechanical model which is the foundation for simulation of corneal microsurgery. Corneal material has two significant characteristics: hyperelastic and viscoelastic. Firstly, Mooney-Rivlin hyperelastic model of cornea obtained based on stored-energy function can be simplified as a linear equation with two unknown parameters. Then, modified Maxwell viscoelastic model of the cornea, whose analytical form is consistent with the generalized Prony-series model, is proposed from the perspective of material mechanics. Parameters of the model are determined by the uniaxial tensile tests and the stress-relaxation tests. Corneal material properties are simulated to verify the hyper-viscoelastic model and measure the effectiveness of the model in the finite element simulation. On this basis, an in vivo model of the corneal is built. And the simulation of extrusion in vivo cornea shows that the force is roughly nonlinearly increasing with displacement, and it is consistent with the results obtained by extrusion experiment of in vivo cornea. Conlusions: This paper derives a corneal hyper-viscoelastic model to describe the material properties more accurately, and explains the mathematical method for determination of the model parameters. The model is an effective biomechanical model, which can be directly used for simulation of trephine and suture in keratoplasty. Although the corneal hyper-viscoelastic model is taken as the object of study, the method has certain adaptability in biomechanical research of ophthalmology.

  16. [Freshwater fish freshness on-line detection method based on near-infrared spectroscopy].

    PubMed

    Huang, Tao; Li, Xiao-Yu; Peng, Yi; Tao, Hai-Long; Li, Peng; Xiong, Shan-Bai

    2014-10-01

    In the present study, the near infrared spectrum of freshwater fish was used to detect the freshness on line, and the near infrared spectra on-line acquisition device was built to get the fish spectrum. In the process of spectrum acquisition, experiment samples move at a speed of 0.5 m · s(-1), the near-infrared diffuse reflection spectrum (900-2,500 nm) could be got for the next analyzing, and SVM was used to build on-line detection model. Sample set partitioning based on joint X-Y distances algo- rithm (SPXY) was used to divide sample set, there were 111 samples in calibration set (57 fresh samples and 54 bad samples), and 37 samples in test set (19 fresh samples and 18 bad samples). Seven spectral preprocessing methods were utilized to prepro- cess the spectrum, and the influences of different methods were compared. Model results indicated that first derivative (FD) with autoscale was the best preprocessing method, the model recognition rate of calibration set was 97.96%, and the recognition rate of test set was 95.92%. In order to improve the modeling speed, it is necessary to optimize the spectra variables. Therefore genetic algorithm (GA), successive projection algorithm (SPA) and competitive adaptive reweighed sampling (CARS) were adopted to select characteristic variables respectively. Finally CARS was proved to be the optimal variable selection method, 10 characteristic wavelengths were selected to develop SVM model, recognition rate of calibration set reached 100%, and recognition rate of test set was 93.88%. The research provided technical reference for freshwater fish freshness online detection.

  17. Experiments in Error Propagation within Hierarchal Combat Models

    DTIC Science & Technology

    2015-09-01

    mean outcome and such a relatively large standard deviation, the best estimate one can give on these results is “better than half.” The other measure ... ERROR PROPAGATION WITHIN HIERARCHAL COMBAT MODELS by Russell G. Pav September 2015 Thesis Advisor: Thomas W. Lucas Second Reader: Jeffrey...DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE EXPERIMENTS IN ERROR PROPAGATION WITHIN HIERARCHAL COMBAT MODELS 5. FUNDING NUMBERS 6

  18. Basin Acoustic Seamount Scattering Experiment (BASSEX) Data Analysis and Modeling

    DTIC Science & Technology

    2007-09-30

    Basin Acoustic Seamount Scattering Experiment (BASSEX) Data Analysis and Modeling Kevin D. Heaney Ocean Acoustical Services and...propagation regimes are the focus of this work: 1.) seamount scattering, 2.) open ocean propagation and 3.) downslope propagation and subsequent deep...water propagation. The long-term goal is understand scattering off of seamounts and island slopes and to develop algorithms for modeling the acoustic

  19. Development of a Fresh Osteochondral Allograft Program Outside North America

    PubMed Central

    Tírico, Luís Eduardo Passarelli; Demange, Marco Kawamura; Santos, Luiz Augusto Ubirajara; de Rezende, Márcia Uchoa; Helito, Camilo Partezani; Gobbi, Riccardo Gomes; Pécora, José Ricardo; Croci, Alberto Tesconi; Bugbee, William Dick

    2015-01-01

    Objective To standardize and to develop a fresh osteochondral allograft protocol of procurement, processing and surgical utilization in Brazil. This study describes the steps recommended to make fresh osteochondral allografts a viable treatment option in a country without previous fresh allograft availability. Design The process involves regulatory process modification, developing and establishing procurement, and processing and surgical protocols. Results Legislation: Fresh osteochondral allografts were not feasible in Brazil until 2009 because the law prohibited preservation of fresh grafts at tissue banks. We approved an amendment that made it legal to preserve fresh grafts for 30 days from 2°C to 6°C in tissue banks. Procurement: We changed the protocol of procurement to decrease tissue contamination. All tissues were procured in an operating room. Processing: Processing of the grafts took place within 12 hours of tissue recovery. A serum-free culture media with antibiotics was developed to store the grafts. Surgeries: We have performed 8 fresh osteochondral allografts on 8 knees obtaining grafts from 5 donors. Mean preoperative International Knee Documentation Committee (IKDC) score was 31.99 ± 13.4, improving to 81.26 ± 14.7 at an average of 24 months’ follow-up. Preoperative Knee Injury and Oseoarthritis Outcome Score (KOOS) score was 46.8 ± 20.9 and rose to 85.24 ± 13.9 after 24 months. Mean preoperative Merle D’Aubigne-Postel score was 8.75 ± 2.25 rising to 16.1 ± 2.59 at 24 months’ follow-up. Conclusion To our knowledge, this is the first report of fresh osteochondral allograft transplantation in South America. We believe that this experience may be of value for physicians in countries that are trying to establish an osteochondral allograft transplant program. PMID:27375837

  20. Development of a Fresh Osteochondral Allograft Program Outside North America.

    PubMed

    Tírico, Luís Eduardo Passarelli; Demange, Marco Kawamura; Santos, Luiz Augusto Ubirajara; de Rezende, Márcia Uchoa; Helito, Camilo Partezani; Gobbi, Riccardo Gomes; Pécora, José Ricardo; Croci, Alberto Tesconi; Bugbee, William Dick

    2016-07-01

    To standardize and to develop a fresh osteochondral allograft protocol of procurement, processing and surgical utilization in Brazil. This study describes the steps recommended to make fresh osteochondral allografts a viable treatment option in a country without previous fresh allograft availability. The process involves regulatory process modification, developing and establishing procurement, and processing and surgical protocols. Legislation: Fresh osteochondral allografts were not feasible in Brazil until 2009 because the law prohibited preservation of fresh grafts at tissue banks. We approved an amendment that made it legal to preserve fresh grafts for 30 days from 2°C to 6°C in tissue banks. Procurement: We changed the protocol of procurement to decrease tissue contamination. All tissues were procured in an operating room. Processing: Processing of the grafts took place within 12 hours of tissue recovery. A serum-free culture media with antibiotics was developed to store the grafts. Surgeries: We have performed 8 fresh osteochondral allografts on 8 knees obtaining grafts from 5 donors. Mean preoperative International Knee Documentation Committee (IKDC) score was 31.99 ± 13.4, improving to 81.26 ± 14.7 at an average of 24 months' follow-up. Preoperative Knee Injury and Oseoarthritis Outcome Score (KOOS) score was 46.8 ± 20.9 and rose to 85.24 ± 13.9 after 24 months. Mean preoperative Merle D'Aubigne-Postel score was 8.75 ± 2.25 rising to 16.1 ± 2.59 at 24 months' follow-up. To our knowledge, this is the first report of fresh osteochondral allograft transplantation in South America. We believe that this experience may be of value for physicians in countries that are trying to establish an osteochondral allograft transplant program.

  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. 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.

  3. Hydrothermal alteration of granite rock cores: experiments and kinetic modelling

    NASA Astrophysics Data System (ADS)

    Kuesters, T.; Mueller, T.; Renner, J.

    2016-12-01

    The kinetics of water-rock interactions at elevated temperatures is key for understanding the dynamic evolution of porosity and permeability in natural and industrial systems. The implementation of rate data in numerical models simulating reactive transport is crucial to reliably predict subsurface fluid flow. The vast majority of data are constrained by single phase powder experiments inhering unrealistically high surface areas and hampering consideration of microstructural effects on reaction progress. We present experimental results of batch experiments conducted at 200 °C for up to 60 days on a quartz-monzodiorite and pure water that bridge the gap between powder experiments and complex natural systems. The effect of reactive surface area was modelled by using bulk-rock powders, intact, and thermally cracked rock cubes. Fluid composition was monitored (ICP-MS) and solid products were analysed after each experiment (SEM, EMPA). The evolution of fluid and solid compositions was compared to a self-coded geochemical transport model accounting for dissolution, nucleation, growth and reactive surface area. Experimental and modelling results indicate a fast increase of Na, Ca, K and Si in the fluid related to kinetically controlled dissolution of feldspar (plg and kfs) and quartz. Maximum concentrations of Al, Mg, and Fe are reached within two days followed by a rapid decrease induced by secondary mineral precipitation. The amount and type of secondary phases strongly depend on the host substrate indicating that local fluid composition and substrate surface are the controlling parameters. Observed reaction rates differ strongly between powder and rock cube experiments due to differences in reactive surface area. Combining kinetic data, gained by modelling the experimental results, with new information on substrate-precipitate relationship will aid large scale-transport models to realistically predict chemo-mechanical changes and fluid flow in subsurface systems.

  4. Testing Numerical Modeling of Phase Coarsening by Microgravity Experiments

    NASA Astrophysics Data System (ADS)

    Wang, K. G.; Glicksman, M. E.

    2017-08-01

    Quantitative understanding of the morphological evolution that occurs during phase coarsening is crucial for optimization of processing procedures to control the final structure and properties of multiphase materials. Generally, ground-based experimental studies of phase coarsening in solids are limited to model alloy systems. Data from microgravity experiments on phase coarsening in Sn-Pb solid-liquid mixtures, executed on the International Space Station, are archived in NASA's Physical Sciences Informatics (PSI) system. In such microgravity experiments, it is expected that the rate of sedimentation will be greatly reduced compared with terrestrial conditions, allowing the kinetics of phase coarsening to be followed more carefully and accurately. In this work we tested existing numerical models of phase coarsening using NASA's PSI microgravity data. Specially, we compared the microstructures derived from phase-field and multiparticle diffusion simulations with those observed in microgravity experiments.

  5. 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.

  6. 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.

  7. Cooperative Education: International Cooperative Work Experience: The ABC Model.

    ERIC Educational Resources Information Center

    Laslett, R. L.; And Others

    1985-01-01

    Describes the nature, implementation, evaluation, and future plans of an international cooperative work experience program (called the ABC model) in which undergraduate students combine travel with employment in industrial research-oriented projects. The program involves universities in Australia, Great Britain, and Canada (the letters ABC…

  8. 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.

  9. 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.

  10. 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)

  11. 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.

  12. Strategy for a Global University: Model International Department Experiment.

    ERIC Educational Resources Information Center

    Lim, Gill-Chin, Ed.; And Others

    This volume contains three case studies and additional information documenting and examining Michigan State University's (MSU) Model International Department Experiment (MIDE), a program designed to encourage internationalization efforts in curricula, research, public service, and outreach activities. Chapter 1, "Introduction: The Rationale…

  13. A Paired Compositions Model for Round-Robin Experiments

    ERIC Educational Resources Information Center

    Gleason, John R.; Halperin, Silas

    1975-01-01

    Investigation of the effects of a series of treatment conditions upon some social behaviors may require observation of subjects mutually paired, in round-robin fashion. Data arising from such experiments are difficult to analyze, partly because they do not fit neatly into standard designs. A model is presented. (Author/BJG)

  14. Modeling of laser knife-edge and pinhole experiments

    NASA Astrophysics Data System (ADS)

    Boley, Charles D.; Estabrook, Kent G.; Auerbach, Jerome M.; Feit, Michael D.; Rubenchik, Alexander M.

    1999-07-01

    We describe simulations of experiments invovling laser illumination of a metallic knife edge in the Optical Sciences Laboratory (OSL) at LLNL, and pinhole closure in the Beamlet experiment at LLNL. The plasma evolution is modeled via LASNEX. In OSL, the calculated phases of a probe beam are found to exhibit the same behavior as in experiment but to be consistently larger. The motion of a given phase contour tends to decelerate at high intensities. At fixed intensity, the speed decreases with atomic mass. We then calculate the plasma associated with 4-leaf pinholes on the Beamlet transport spatial filter. We employ a new propagation code to follow a realistic input beam through the entire spatial filter, including the plasmas. The detailed behavior of the output wavefronts is obtained. We show how closure depends on the orientation and material of the pinholes blades. As observed in experiment, a diamond orientation is preferable to a square orientation, and tantalum performs better than stainless steel.

  15. Multicomponent reactive transport modeling of uranium bioremediation field experiments

    NASA Astrophysics Data System (ADS)

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

    2009-10-01

    A reaction network integrating abiotic and microbially mediated reactions has been developed to simulate biostimulation field experiments at a former Uranium Mill Tailings Remedial Action (UMTRA) site in Rifle, Colorado. The reaction network was calibrated using data from the 2002 field experiment, after which it was applied without additional calibration to field experiments performed in 2003 and 2007. 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 terminal electron-accepting processes (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 UMTRA site that demonstrated that the bulk (˜90%) of initial Fe(III) bioreduction is associated with phyllosilicate rather than oxide forms of iron. The uranium reaction network includes a U(VI) surface complexation model based on laboratory studies with Rifle site sediments and aqueous complexation reactions that include ternary complexes (e.g., calcium-uranyl-carbonate). The bioreduced U(IV), Fe(II), and sulfide components produced during the experiments are strongly associated with the solid phases and may play an important role in long-term uranium immobilization.

  16. Evaluation of a Neuromechanical Walking Control Model Using Disturbance Experiments

    PubMed Central

    Song, Seungmoon; Geyer, Hartmut

    2017-01-01

    Neuromechanical simulations have been used to study the spinal control of human locomotion which involves complex mechanical dynamics. So far, most neuromechanical simulation studies have focused on demonstrating the capability of a proposed control model in generating normal walking. As many of these models with competing control hypotheses can generate human-like normal walking behaviors, a more in-depth evaluation is required. Here, we conduct the more in-depth evaluation on a spinal-reflex-based control model using five representative gait disturbances, ranging from electrical stimulation to mechanical perturbation at individual leg joints and at the whole body. The immediate changes in muscle activations of the model are compared to those of humans across different gait phases and disturbance magnitudes. Remarkably similar response trends for the majority of investigated muscles and experimental conditions reinforce the plausibility of the reflex circuits of the model. However, the model's responses lack in amplitude for two experiments with whole body disturbances suggesting that in these cases the proposed reflex circuits need to be amplified by additional control structures such as location-specific cutaneous reflexes. A model that captures these selective amplifications would be able to explain both steady and reactive spinal control of human locomotion. Neuromechanical simulations that investigate hypothesized control models are complementary to gait experiments in better understanding the control of human locomotion. PMID:28381996

  17. Manipulators with flexible links: A simple model and experiments

    NASA Technical Reports Server (NTRS)

    Shimoyama, Isao; Oppenheim, Irving J.

    1989-01-01

    A simple dynamic model proposed for flexible links is briefly reviewed and experimental control results are presented for different flexible systems. A simple dynamic model is useful for rapid prototyping of manipulators and their control systems, for possible application to manipulator design decisions, and for real time computation as might be applied in model based or feedforward control. Such a model is proposed, with the further advantage that clear physical arguments and explanations can be associated with its simplifying features and with its resulting analytical properties. The model is mathematically equivalent to Rayleigh's method. Taking the example of planar bending, the approach originates in its choice of two amplitude variables, typically chosen as the link end rotations referenced to the chord (or the tangent) motion of the link. This particular choice is key in establishing the advantageous features of the model, and it was used to support the series of experiments reported.

  18. 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.

  19. Rapid Testing of Fresh Concrete

    DTIC Science & Technology

    1975-05-01

    Board (1962), pp 1-29. 18 Lorman, W. R., "Plastic Concrete Quality Control," Technical Note N-395 (U.S. Naval Civil Engineering Laboratory, 1961...Fresh Concrete, Presented at the 54th Annual Meeting of the Transportation Research Board , Washington, D.C., January, 1975. 11 30 solution Is...the 54th Annual Meeting of the Transportation Research Board , Washington, D.C., January, 1975. 12 Chadda, L. R., "The Rapiri Determination of

  20. Vibrational kinetics in CO electric discharge lasers - Modeling and experiments

    NASA Technical Reports Server (NTRS)

    Stanton, A. C.; Hanson, R. K.; Mitchner, M.

    1980-01-01

    A model of CO laser vibrational kinetics is developed, and predicted vibrational distributions are compared with measurements. The experimental distributions were obtained at various flow locations in a transverse CW discharge in supersonic (M = 3) flow. Good qualitative agreement is obtained in the comparisons, including the prediction of a total inversion at low discharge current densities. The major area of discrepancy is an observed loss in vibrational energy downstream of the discharge which is not predicted by the model. This discrepancy may be due to three-dimensional effects in the experiment which are not included in the model. Possible kinetic effects which may contribute to vibrational energy loss are also examined.

  1. 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.

  2. Event-based Simulation Model for Quantum Optics Experiments

    NASA Astrophysics Data System (ADS)

    De Raedt, H.; Michielsen, K.

    2011-03-01

    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.

  3. Electromagnetic sunscreen model: design of experiments on particle specifications.

    PubMed

    Lécureux, Marie; Deumié, Carole; Enoch, Stefan; Sergent, Michelle

    2015-10-01

    We report a numerical study on sunscreen design and optimization. Thanks to the combined use of electromagnetic modeling and design of experiments, we are able to screen the most relevant parameters of mineral filters and to optimize sunscreens. Several electromagnetic modeling methods are used depending on the type of particles, density of particles, etc. Both the sun protection factor (SPF) and the UVB/UVA ratio are considered. We show that the design of experiments' model should include interactions between materials and other parameters. We conclude that the material of the particles is a key parameter for the SPF and the UVB/UVA ratio. Among the materials considered, none is optimal for both. The SPF is also highly dependent on the size of the particles.

  4. Analysis of a DNA simulation model through hairpin melting experiments

    PubMed Central

    Linak, Margaret C.; Dorfman, Kevin D.

    2010-01-01

    We compare the predictions of a two-bead Brownian dynamics simulation model to melting experiments of DNA hairpins with complementary AT or GC stems and noninteracting loops in buffer A. This system emphasizes the role of stacking and hydrogen bonding energies, which are characteristics of DNA, rather than backbone bending, stiffness, and excluded volume interactions, which are generic characteristics of semiflexible polymers. By comparing high throughput data on the open-close transition of various DNA hairpins to the corresponding simulation data, we (1) establish a suitable metric to compare the simulations to experiments, (2) find a conversion between the simulation and experimental temperatures, and (3) point out several limitations of the model, including the lack of G-quartets and cross stacking effects. Our approach and experimental data can be used to validate similar coarse-grained simulation models. PMID:20886965

  5. Modeling the Brownian relaxation of nanoparticle ferrofluids: Comparison with experiment

    PubMed Central

    Martens, Michael A.; Deissler, Robert J.; Wu, Yong; Bauer, Lisa; Yao, Zhen; Brown, Robert; Griswold, Mark

    2013-01-01

    Purpose: The authors investigate the ability of current models for magnetic nanoparticles immersed in dilute ferrofluids and external sinusoidal magnetic fields to explain recent experiments in which the relaxation effects are dominated by viscous damping. Methods: The Fokker–Planck (FP) equation appropriate for the nanoparticle magnetic moment distribution corresponding to the underlying stochastic Langevin model is numerically studied and solutions compared to experimental results. The FP equation is solved using an expansion in Legendre polynomials. The polydisperse properties of the ferrofluids are incorporated into the analysis. Results: By using a FP approach that includes polydispersion, the authors obtain good agreement with recent experimental results using ferrofluids containing nanoparticles with average hydrodynamic diameters in the 40–120 nm range. Conclusions: For nanoparticles used in recent magnetic spectroscopy experiments, the FP approach can be used to accurately model experimental data in the situation where Brownian relaxation effects are dominant and the ferrofluids are dilute. PMID:23387765

  6. Modeling the Brownian relaxation of nanoparticle ferrofluids: comparison with experiment.

    PubMed

    Martens, Michael A; Deissler, Robert J; Wu, Yong; Bauer, Lisa; Yao, Zhen; Brown, Robert; Griswold, Mark

    2013-02-01

    The authors investigate the ability of current models for magnetic nanoparticles immersed in dilute ferrofluids and external sinusoidal magnetic fields to explain recent experiments in which the relaxation effects are dominated by viscous damping. The Fokker-Planck (FP) equation appropriate for the nanoparticle magnetic moment distribution corresponding to the underlying stochastic Langevin model is numerically studied and solutions compared to experimental results. The FP equation is solved using an expansion in Legendre polynomials. The polydisperse properties of the ferrofluids are incorporated into the analysis. By using a FP approach that includes polydispersion, the authors obtain good agreement with recent experimental results using ferrofluids containing nanoparticles with average hydrodynamic diameters in the 40-120 nm range. For nanoparticles used in recent magnetic spectroscopy experiments, the FP approach can be used to accurately model experimental data in the situation where Brownian relaxation effects are dominant and the ferrofluids are dilute.

  7. Analysis of the Second Model Parameter Estimation Experiment Workshop Results

    NASA Astrophysics Data System (ADS)

    Duan, Q.; Schaake, J.; Koren, V.; Mitchell, K.; Lohmann, D.

    2002-05-01

    The goal of Model Parameter Estimation Experiment (MOPEX) is to investigate techniques for the a priori parameter estimation for land surface parameterization schemes of atmospheric models and for hydrologic models. A comprehensive database has been developed which contains historical hydrometeorologic time series data and land surface characteristics data for 435 basins in the United States and many international basins. A number of international MOPEX workshops have been convened or planned for MOPEX participants to share their parameter estimation experience. The Second International MOPEX Workshop is held in Tucson, Arizona, April 8-10, 2002. This paper presents the MOPEX goal/objectives and science strategy. Results from our participation in developing and testing of the a priori parameter estimation procedures for the National Weather Service (NWS) Sacramento Soil Moisture Accounting (SAC-SMA) model, the Simple Water Balance (SWB) model, and the National Center for Environmental Prediction Center (NCEP) NOAH Land Surface Model (NOAH LSM) are highlighted. The test results will include model simulations using both a priori parameters and calibrated parameters for 12 basins selected for the Tucson MOPEX Workshop.

  8. 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.

  9. Modeling of NIF Wetted-Foam Capsule Experiments

    NASA Astrophysics Data System (ADS)

    Peterson, Robert; Olson, Richard; Kline, John

    2015-11-01

    Wetting of a foam with liquid DT or DD in an ICF capsule provides a mechanism of directly controlling the convergence ratio of the implosion. The density of the DD or DT vapor in the central void in the CH foam is set by the temperature of the liquid fuel, so the convergence ratio is easily adjustable. The capsule is driven by a two step laser pulse on NIF. The ablator is made of high density carbon in these experiments, but it could be beryllium. The experiments will test how well the modeling computer codes agree with experiment as the convergence ratio increases. It is possible that has the convergence ratio increases, a point will be reached were the modeling no longer agree with experiment. We wish to find this limit. In the presentation we will present computer model simulations in 1-D of the performance of NIF wetted-foam capsules, where the vapor density, the ablator type, and the choice of fuel (DD or DT) are varied.

  10. 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.

  11. 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 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...

  12. 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).

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. [New index for crop canopy fresh biomass estimation].

    PubMed

    Chen, Peng-Fei; Nicolas, Tremblay; Wang, Ji-Hua; Philippe, Vigneault; Huang, Wen-Jiang; Li, Bao-Guo

    2010-02-01

    The objective of the present study is to propose a new vegetation index for corn canopy fresh biomass estimation, which improves the ability to accurately estimate high biomass levels by remote sensing technology. For this purpose, hyperspectral reflectance data of corn canopies were collected using a ground-based spectroradiometer during different field campaigns in a region of Quebec (Canada), from 2004 to 2008. Corresponding fresh biomass values were obtained by destructive measurements, and a hyperspectral image was also acquired using the Compact Airborne Spectrographic Imager (CASI) in 2005. A new biomass index named red-edge triangular vegetation index (RTVI) was designed and compared to existing indices used for fresh biomass estimation. The results showed that RTVI was the best vegetation index for predicting canopy fresh biomass, with sustained sensitivity at high fresh biomass levels. The best regression model between RTVI and canopy fresh biomass was the power fit, with determination coefficient (R2) of 0.96. With the validation by CASI imagery in 2005, good results were obtained. The relationship between CASI predicted biomass and actual biomass was 0.58 (R2), with the RMSE of 0.44 kg x m(-2).

  1. Warm fresh whole blood and thoracic traumain iraq and afghanistan.

    PubMed

    Keneally, Ryan J; Parsons, Andrew M; Willett, Peter B

    2015-01-01

    Thoracic trauma occurred in 10% of the patients seen at US military treatment facilities in Iraq and Afghanistan and 52% of those patients were transfused. Among those transfused, 281 patients received warm fresh whole blood. A previous report documented improved survival with warm fresh whole blood in patients injured in combat without stratification by injury pattern. A later report described an increase in acute lung injuries after its administration. Survivorship and warm fresh whole blood have never been analyzed in a subpopulation at highest risk for lung injuries, such as patients with thoracic trauma. There may be a heterogeneous relationship between whole blood and survival based on likelihood of a concomitant pulmonary injury. In this report, the relationship between warm fresh whole blood and survivorship was analyzed among patients at highest risk for concomitant pulmonary injuries. Patients with thoracic trauma who received a transfusion were identified in the Joint Theater Trauma Registry. Gross mortality rates were compared between whole blood recipients and patients transfused with component therapy only. The association between each blood component and mortality was determined in a regression model. The overall mortality risk was compared between warm fresh whole blood recipients and non-recipients. Patients transfused with warm fresh whole blood in addition to component therapy had a higher mortality rate than patients transfused only separated blood components (21.3% vs. 12.8%, P < 0.001). When controlling for covariates, transfusion of warm fresh whole blood in addition to component therapy was not associated with increased mortality risk compared with the transfusion of component therapy only (OR 1.247 [95% CI 0.760-2.048], P = 0.382). Patients with combat related thoracic trauma transfused with warm fresh whole blood were not at increased risk for mortality compared to those who received component therapy alone when controlling for covariates.

  2. 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

  3. Study on storage efficiency of the fresh food e-commerce

    NASA Astrophysics Data System (ADS)

    Wang, Xin; Sun, Jie; Li, Huihui

    2017-06-01

    As the last cake in the area of e-commerce industry, the temperature of fresh food e-commerce is always rising starting from about 2014. This paper is based on the imperfection that the existing study about fresh food e-commerce is lack of studies on storage efficiency. And we took some variables in this paper such as consumers’ satisfaction and length for preservation and storage time. On this basis we built the model of storage efficiency of fresh food e-commerce. We find that as the development of fresh food e-commerce, the fresh food e-commerce enterprise will pay more attention to the consumers’ satisfaction. They can take some effective ways like reducing the wastage of fresh food and lengthening the refreshing time of fresh food and so on.

  4. Modelling the effect of shear strength on isentropic compression experiments

    NASA Astrophysics Data System (ADS)

    Thomson, Stuart; Howell, Peter; Ockendon, John; Ockendon, Hilary

    2017-01-01

    Isentropic compression experiments (ICE) are a way of obtaining equation of state information for metals undergoing violent plastic deformation. In a typical experiment, millimetre thick metal samples are subjected to pressures on the order of 10 - 102 GPa, while the yield strength of the material can be as low as 10-2 GPa. The analysis of such experiments has so far neglected the effect of shear strength, instead treating the highly plasticised metal as an inviscid compressible fluid. However making this approximation belies the basic elastic nature of a solid object. A more accurate method should strive to incorporate the small but measurable effects of shear strength. Here we present a one-dimensional mathematical model for elastoplasticity at high stress which allows for both compressibility and the shear strength of the material. In the limit of zero yield stress this model reproduces the hydrodynamic models currently used to analyse ICEs. Numerical solutions of the governing equations will then be presented for problems relevant to ICEs in order to investigate the effects of shear strength compared with a model based purely on hydrodynamics.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  6. 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.

  7. 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.

  8. 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.

  9. Modelling of lithium erosion and transport in FTU lithium experiments

    NASA Astrophysics Data System (ADS)

    Ding, R.; Maddaluno, G.; Apicella, M. L.; Mazzitelli, G.; Pericoli Ridolfini, V.; Kirschner, A.; Chen, J. L.; Li, J. G.; Luo, G.-N.

    2013-07-01

    The ERO code has been used to simulate lithium erosion, transport and re-deposition from liquid lithium limiter experiments in FTU. Two different operational cases from LLL experiments with different plasma parameters and surface temperature are modelled. According to the effective lithium sputtering yields, for both cases the lithium erosion is mainly due to physical sputtering rather than evaporation. Furthermore, the modelled re-deposition fraction of evaporated lithium is much higher than that of sputtered lithium, which is due to the shorter ionisation mean free path of thermal lithium atoms. Therefore, the evaporation erosion effect can be neglected compared to physical sputtering when the surface temperature is below 450 °C. According to the simulations, most of the lithium impurities exist in the form of Li+, and the main plasma contamination by lithium ions is low because most of eroded lithium particles are not transported into the core plasma and stay outside of the LCFS.

  10. Chemical and Flowfield Modeling for Enhanced Analysis of Contamination Experiments

    NASA Technical Reports Server (NTRS)

    Braunstein, Matthew; Finchum, Andy (Technical Monitor)

    2001-01-01

    This paper describes the application of a new Direct Simulation Monte Carlo (DSMC) code, the Molecular Beam Simulator (MBS), which is designed to analyze laboratory scale molecular beam-surface (and crossed-beam) experiments. The MBS is primarily intended to model experiments associated with spacecraft contamination effects, but it can also be used to simulate a variety of surface chemistry and reactive flow measurements. The MBS code is fully three-dimensional, includes a wide-range of chemical processes, and can model one or multiple pulsed (non-steady) sources. As an example application of the MBS code, a fast, pulsed, oxygen atom-surface experiment which examines the chemistry behind erosion of graphite by oxygen atoms is analyzed. Unsteady DSMC simulations show that experimental observations of excited molecular states after the pulse has hit the surface are consistent with two distinct chemical mechanisms: a direct one where the excited molecules are formed on the surface, and a two-step mechanism where ground state molecules formed on the surface are collisionally excited after they leave the surface by trailing oxygen atoms in the pulse. Further DSMC calculations suggest experiments which can distinguish between these mechanisms.

  11. Modeling Contaminants in AP-MS/MS Experiments

    PubMed Central

    Lavallée-Adam, Mathieu; Cloutier, Philippe; Coulombe, Benoit; Blanchette, Mathieu

    2015-01-01

    Identification of protein–protein interactions (PPI) by affinity purification (AP) coupled with tandem mass spectrometry (AP-MS/MS) produces large data sets with high rates of false positives. This is in part because of contamination at the AP level (due to gel contamination, nonspecific binding to the TAP columns in the context of tandem affinity purification, insufficient purification, etc.). In this paper, we introduce a Bayesian approach to identify false-positive PPIs involving contaminants in AP-MS/MS experiments. Specifically, we propose a confidence assessment algorithm (called Decontaminator) that builds a model of contaminants using a small number of representative control experiments. It then uses this model to determine whether the Mascot score of a putative prey is significantly larger than what was observed in control experiments and assigns it a p-value and a false discovery rate. We show that our method identifies contaminants better than previously used approaches and results in a set of PPIs with a larger overlap with databases of known PPIs. Our approach will thus allow improved accuracy in PPI identification while reducing the number of control experiments required. PMID:21117706

  12. 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.

  13. 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

  14. Hypergraph-based recognition memory model for lifelong experience.

    PubMed

    Kim, Hyoungnyoun; Park, Ji-Hyung

    2014-01-01

    Cognitive agents are expected to interact with and adapt to a nonstationary dynamic environment. As an initial process of decision making in a real-world agent interaction, familiarity judgment leads the following processes for intelligence. Familiarity judgment includes knowing previously encoded data as well as completing original patterns from partial information, which are fundamental functions of recognition memory. Although previous computational memory models have attempted to reflect human behavioral properties on the recognition memory, they have been focused on static conditions without considering temporal changes in terms of lifelong learning. To provide temporal adaptability to an agent, in this paper, we suggest a computational model for recognition memory that enables lifelong learning. The proposed model is based on a hypergraph structure, and thus it allows a high-order relationship between contextual nodes and enables incremental learning. Through a simulated experiment, we investigate the optimal conditions of the memory model and validate the consistency of memory performance for lifelong learning.

  15. Hypergraph-Based Recognition Memory Model for Lifelong Experience

    PubMed Central

    2014-01-01

    Cognitive agents are expected to interact with and adapt to a nonstationary dynamic environment. As an initial process of decision making in a real-world agent interaction, familiarity judgment leads the following processes for intelligence. Familiarity judgment includes knowing previously encoded data as well as completing original patterns from partial information, which are fundamental functions of recognition memory. Although previous computational memory models have attempted to reflect human behavioral properties on the recognition memory, they have been focused on static conditions without considering temporal changes in terms of lifelong learning. To provide temporal adaptability to an agent, in this paper, we suggest a computational model for recognition memory that enables lifelong learning. The proposed model is based on a hypergraph structure, and thus it allows a high-order relationship between contextual nodes and enables incremental learning. Through a simulated experiment, we investigate the optimal conditions of the memory model and validate the consistency of memory performance for lifelong learning. PMID:25371665

  16. 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.

  17. 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.

  18. 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.

  19. Basin Acoustic Seamount Scattering Experiment (BASSEX) Data Analysis and Modeling

    DTIC Science & Technology

    2005-08-30

    shadow zone produced by seamounts with vertical extensions into the sound channel axis have been made. Measurements of 3D propagation have been made off...Basin Acoustic Seamount Scattering Experiment (BASSEX) Data Analysis and Modeling Kevin D. Heaney Ocean Acoustical Services and...propagation regimes are the focus of this work: 1.) seamount scattering, 2.) open ocean propagation and 3.) downslope propagation in a

  20. 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.

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

    PubMed Central

    2016-01-01

    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

  2. Soil remediation by heat injection: Experiments and numerical modelling

    SciTech Connect

    Betz, C.; Emmert, M.; Faerber, A.

    1995-03-01

    In order to understand physical processes of thermally enhanced soil vapor extraction methods in porous media the isothermal, multiphase formulation for the numerical model MUFTE will be extended by a non-isothermal, multiphase-multicomponent formulation. In order to verify the numerical model, comparison with analytical solutions for well defined problems will be carried out. To identify relevant processes and their interactions, the results of the simulation will be compared with well controlled experiments with sophisticated measurement equipment in three different scales. The aim is to compare the different numerical solution techniques namely Finite Element versus Integral Finite Difference technique as implemented in MUFTE and TOUGH2 [9] respectively.

  3. 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

  4. Analysis and Modeling of Practical Experiment on IP Traffic Control

    NASA Astrophysics Data System (ADS)

    Suzuki, Tadamichi; Ito, Jungo; Nakano, Kazushi; Miki, Tetsuya

    In this paper, we focus on a practical experiment concerning IP traffic engineering over Multi-Protocol Label Switching (MPLS), especially which features feedback control capabilities. We present control-theoretic analysis of the experimental results based on acquired knowledge of actual network behavior. Because stable automated control capabilities are key issues in IP traffic engineering, we model an IP traffic control system based on the resulting analysis. In addition, comparison between simulated network behavior and actual one shows this model to have a high degree of stability, with a high potential for application to real networks.

  5. 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

  6. An energetic model for macromolecules unfolding in stretching experiments.

    PubMed

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

    2013-11-06

    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.

  7. Model Analysis of Vertical Carbon Export in a Mesocosm Experiment

    NASA Astrophysics Data System (ADS)

    Mathesius, S.

    2016-02-01

    Marine biogeochemical models can be improved by developing a deeper understanding of the necessary degree of model complexity, which includes for example the investigation of non-unique solutions in parameter optimization problems. The examination of uniqueness and uncertainties of optimal parameter estimates might disclose the relevance of individual processes. With our data based model analysis we will explore the possibility of explaining similar patterns in observations that could possibly be explained equally well by different parameter settings or even different parameterizations. Here, we show the results of an optimality based plankton ecosystem model (Carbon:Nitrogen-Regulated Ecosystem Model with Coccolithophores, CN-REcoM&Co). The model includes carbonate chemistry (with air-sea flux of carbon dioxide) and its setup was designed to simulate plankton dynamics observed during a mesocosm experiment (PeECE III, Bergen, Norway, 2005). A special model feature is the explicit consideration of extracellular gels that form from coagulation of algal exudates. These macrogels interact (aggregate) with detritus and become incorporated into sinking particles. In our analysis we focus on those parameters that affect photosynthesis, exudation of polysaccharides, grazing, particle aggregation and sinking. We will discuss how variations of these parameter values induce variability in chlorophyll a, dissolved inorganic carbon (DIC), and particulate organic carbon (POC) concentrations, as well as carbon export flux. Our primary concern is to disclose the uniqueness of the model solution that explains the observed DIC drawdown as well as the build-up and sinking loss of POC from the upper layers.

  8. Fatigue Damage of Collagenous Tissues: Experiment, Modeling and Simulation Studies

    PubMed Central

    Martin, Caitlin; Sun, Wei

    2017-01-01

    Mechanical fatigue damage is a critical issue for soft tissues and tissue-derived materials, particularly for musculoskeletal and cardiovascular applications; yet, our understanding of the fatigue damage process is incomplete. Soft tissue fatigue experiments are often difficult and time-consuming to perform, which has hindered progress in this area. However, the recent development of soft-tissue fatigue-damage constitutive models has enabled simulation-based fatigue analyses of tissues under various conditions. Computational simulations facilitate highly controlled and quantitative analyses to study the distinct effects of various loading conditions and design features on tissue durability; thus, they are advantageous over complex fatigue experiments. Although significant work to calibrate the constitutive models from fatigue experiments and to validate predictability remains, further development in these areas will add to our knowledge of soft-tissue fatigue damage and will facilitate the design of durable treatments and devices. In this review, the experimental, modeling, and simulation efforts to study collagenous tissue fatigue damage are summarized and critically assessed. PMID:25955007

  9. 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.

  10. 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.

  11. 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…

  12. 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…

  13. 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

  14. Numerical Modelling of Solitary Wave Experiments on Rubble Mound Breakwaters

    NASA Astrophysics Data System (ADS)

    Guler, H. G.; Arikawa, T.; Baykal, C.; Yalciner, A. C.

    2016-12-01

    Performance of a rubble mound breakwater protecting Haydarpasa Port, Turkey, has been tested under tsunami attack by physical model tests conducted at Port and Airport Research Institute (Guler et al, 2015). It is aimed to understand dynamic force of the tsunami by conducting solitary wave tests (Arikawa, 2015). In this study, the main objective is to perform numerical modelling of solitary wave tests in order to verify accuracy of the CFD model IHFOAM, developed in OpenFOAM environment (Higuera et al, 2013), by comparing results of the numerical computations with the experimental results. IHFOAM is the numerical modelling tool which is based on VARANS equations with a k-ω SST turbulence model including realistic wave generation, and active wave absorption. Experiments are performed using a Froude scale of 1/30, measuring surface elevation and flow velocity at several locations in the wave channel, and wave pressure around the crown wall of the breakwater. Solitary wave tests with wave heights of H=7.5 cm and H=10 cm are selected which represent the results of the experiments. The first test (H=7.5 cm) is the case that resulted in no damage whereas the second case (H=10 cm) resulted in total damage due to the sliding of the crown wall. After comparison of the preliminary results of numerical simulations with experimental data for both cases, it is observed that solitary wave experiments could be accurately modeled using IHFOAM focusing water surface elevations, flow velocities, and wave pressures on the crown wall of the breakwater (Figure, result of sim. at t=29.6 sec). ACKNOWLEDGEMENTSThe authors acknowledge developers of IHFOAM, further extend their acknowledgements for the partial supports from the research projects MarDiM, ASTARTE, RAPSODI, and TUBITAK 213M534. REFERENCESArikawa (2015) "Consideration of Characteristics of Pressure on Seawall by Solitary Waves Based on Hydraulic Experiments", Jour. of Japan. Soc. of Civ. Eng. Ser. B2 (Coast. Eng.), Vol 71, p I

  15. 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

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

    PubMed

    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.

  17. 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).

  18. A fresh look at dense hydrogen under pressure. II. Chemical and physical models aiding our understanding of evolving H-H separations.

    PubMed

    Labet, Vanessa; Hoffmann, Roald; Ashcroft, N W

    2012-02-21

    In order to explain the intricate dance of intramolecular (intra-proton-pair) H-H separations observed in a numerical laboratory of calculationally preferred static hydrogen structures under pressure, we examine two effects through discrete molecular models. The first effect, we call it physical, is of simple confinement. We review a salient model already in the literature, that of LeSar and Herschbach, of a hydrogen molecule in a spheroidal cavity. As a complement, we also study a hydrogen molecule confined along a line between two helium atoms. As the size of the cavity/confining distance decreases (a surrogate for increasing pressure), in both models the equilibrium proton separation decreases and the force constant of the stretching vibration increases. The second effect, which is an orbital or chemical factor, emerges from the electronic structure of the known molecular transition metal complexes of dihydrogen. In these the H-H bond is significantly elongated (and the vibron much decreased in frequency) as a result of depopulation of the σ(g) bonding molecular orbital of H(2), and population of the antibonding σ(u)∗ MO. The general phenomenon, long known in chemistry, is analyzed through a specific molecular model of three hydrogen molecules interacting in a ring, a motif found in some candidate structures for dense hydrogen.

  19. 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

  20. Analysis of Fresh and Aged Aerosols Produced by Biomass Combustion

    NASA Astrophysics Data System (ADS)

    Holden, A. S.; Desyaterik, Y.; Laskin, A.; Laskin, J.; Schichtel, B. A.; Malm, W. C.; Kreidenweis, S. M.; Collett, J. L.

    2010-12-01

    Emissions from biomass combustion are known to influence human health, visibility, the global radiation budget, and cloud properties. Much research has been done looking at the primary emissions of wild and prescribed fires. As a result, primary smoke marker compounds, such as levoglucosan (a combustion product of cellulose), have been identified and used to determine the impact of fires on ambient air quality. However, little is known about the chemical processing occurring within smoke plumes and the resulting production of secondary organic aerosols (SOA). This likely leads to an underestimation of biomass burning impacts on particulate organic carbon (OC), often used in large-scale air quality model simulations. To better understand biomass smoke aging, hi-volume PM2.5 filter samples from two studies are compared here. Data from the Fire Lab at Missoula Experiments (FLAME) represent fresh smoke, sampled at the source of the fire. Aged smoke was collected during the Yosemite Aerosol Characterization Study (YACS), where the sampling site was days downwind from forest fires. Additional samples of aged smoke were collected at Rocky Mountain National Park and the Colorado State University Atmospheric Science Department, which were both affected by transported smoke from wildfires in southern California. Aqueous extracts of these samples have been analyzed using Liquid Chromatography coupled with a Time-of-Flight Mass Spectrometer (LC-TOF-MS) with electrospray ionization, as well as with a Linear Trap Quadrupole-Orbitrap Mass Spectrometr (LTQ-Orbitrap MS). Samples of fresh and aged smoke will be compared to help identify processes occurring during biomass smoke aging and transport. Preliminary results have shown the products of monoterpene oxidation, such as limonene, in all samples. Analysis has also shown an abundance of nitrogen-containing compounds in samples affected by biomass smoke, as well as an increase in oxidation with aged smoke samples.

  1. On the Design of Climate Change Modelling Experiments

    NASA Astrophysics Data System (ADS)

    Smith, L.

    2003-04-01

    Perhaps the greatest challenge in modelling physical systems is to estimate (quantitatively) how a system will react to a time dependent change in forcing which will explore regions of parameter space for which little or no observational data is to hand. Climate change modelling is the prime example of this task. A key issue here how to best distribute limited computational resource between quantifying the behaviour of a given model and various methods of quantifying the uncertainties in that behaviour; the latter may be due to differences in initial condition, parameter values, and even model structure (see L.A. Smith, 2002, What Might We Learn from Climate Forecasts? Proc. National Acad. Sci., 4, 99, 2487--2492). The experimental design of ensemble climate forecasting in climateprediction.net will be discussed in this light. Particular attention will be focused on how to best explore the sensitively of the model to changes in parameters while minimising the distractions caused by inevitable false positives which will be `identified' when exploring systems with this many (interesting) degrees of freedom. The approach is based upon identifying unlikely deviations given the distribution of likely results under the standard parameter values, repeated sampling of parameter sets to distinguish true model sensitivity from the low probability events which must be expected in large ensemble experiments, and attempts to identify the forecast quantities of interest (which model outputs will be studied) as early as possible, if not a priori.

  2. 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

  3. Gravitational Acceleration Effects on Macrosegregation: Experiment and Computational Modeling

    NASA Technical Reports Server (NTRS)

    Leon-Torres, J.; Curreri, P. A.; Stefanescu, D. M.; Sen, S.

    1999-01-01

    Experiments were performed under terrestrial gravity (1g) and during parabolic flights (10-2 g) to study the solidification and macrosegregation patterns of Al-Cu alloys. Alloys having 2% and 5% Cu were solidified against a chill at two different cooling rates. Microscopic and Electron Microprobe characterization was used to produce microstructural and macrosegregation maps. In all cases positive segregation occurred next to the chill because shrinkage flow, as expected. This positive segregation was higher in the low-g samples, apparently because of the higher heat transfer coefficient. A 2-D computational model was used to explain the experimental results. The continuum formulation was employed to describe the macroscopic transports of mass, energy, and momentum, associated with the solidification phenomena, for a two-phase system. The model considers that liquid flow is driven by thermal and solutal buoyancy, and by solidification shrinkage. The solidification event was divided into two stages. In the first one, the liquid containing freely moving equiaxed grains was described through the relative viscosity concept. In the second stage, when a fixed dendritic network was formed after dendritic coherency, the mushy zone was treated as a porous medium. The macrosegregation maps and the cooling curves obtained during experiments were used for validation of the solidification and segregation model. The model can explain the solidification and macrosegregation patterns and the differences between low- and high-gravity results.

  4. Modeling and experiments with a subsea laser radar system

    NASA Astrophysics Data System (ADS)

    Bjarnar, Morten L.; Klepsvik, John O.; Nilsen, Jan E.

    1991-12-01

    Subsea laser radar has a potential for accurate 3-D imaging in water. A prototype system has been developed at Seatex A/S in Norway as a prestudy for the design of an underwater laser radar scanning system. Parallel to the experimental studies, a numerical radiometric model has been developed as an aid in the system design. This model simulates a raster scanning laser radar system for in-water use. Thus this parametric model allows for analysis and predictions of the performance of such a sensor system. Experiments have been conducted to test a prototype laser radar system. The experimental system tested uses a Q-switched, frequency doubled, Nd:YAG solid state laser operating at a wavelength of 532 nm, which is close to optimal for use in water due to the small light attenuation around this wavelength in seawater. The laser has an energy output of 6 (mu) J per pulse 1 kHz pulse repetition frequency (PRF) and the receiver aperture is approximately 17 cm2. The laser radar prototype was mounted onto an accurate pan and tilt unit in order to test the 3-D imaging capabilities. The ultimate goal of the development is to provide an optical 3-D imaging tool for distances comparable to high frequency sonars with a range capability of approximately 30 - 50 m. The results from these experiments are presented. The present implementation of the scanning laser radar model is described and some outputs from the simulation are shown.

  5. 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.

  6. 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.!

  7. Reverse draw solute permeation in forward osmosis: modeling and experiments.

    PubMed

    Phillip, William A; Yong, Jui Shan; Elimelech, Menachem

    2010-07-01

    Osmotically driven membrane processes are an emerging set of technologies that show promise in water and wastewater treatment, desalination, and power generation. The effective operation of these systems requires that the reverse flux of draw solute from the draw solution into the feed solution be minimized. A model was developed that describes the reverse permeation of draw solution across an asymmetric membrane in forward osmosis operation. Experiments were carried out to validate the model predictions with a highly soluble salt (NaCl) as a draw solution and a cellulose acetate membrane designed for forward osmosis. Using independently determined membrane transport coefficients, strong agreement between the model predictions and experimental results was observed. Further analysis shows that the reverse flux selectivity, the ratio of the forward water flux to the reverse solute flux, is a key parameter in the design of osmotically driven membrane processes. The model predictions and experiments demonstrate that this parameter is independent of the draw solution concentration and the structure of the membrane support layer. The value of the reverse flux selectivity is determined solely by the selectivity of the membrane active layer.

  8. Modelling phosphorus transport and its response to climate change at upper stream of Poyang Lake-the largest fresh water lake in China

    NASA Astrophysics Data System (ADS)

    Jiang, Sanyuan; Zhang, Qi

    2017-04-01

    Phosphorus losses from excessive fertilizer application and improper land exploitation were found to be the limiting factor for freshwater quality deterioration and eutrophication. Phosphorus transport from uplands to river is related to hydrological, soil erosion and sediment transport processes, which is impacted by several physiographic and meteorological factors. The objective of this study was to investigate the spatiotemporal variation of phosphorus losses and response to climate change at a typical upstream tributary (Le'An river) of Poyang Lake. To this end, a process-oriented hydrological and nutrient transport model HYPE (Hydrological Predictions for the Environment) was set up for discharge and phosphorus transport simulation at Le'An catchment. Parameter ESTimator (PEST) was combined with HYPE model for parameter sensitivity analysis and optimisation. In runoff modelling, potential evapotranspiration rate of the dominant land use (forest) is most sensitive; parameters of surface runoff rate and percolation capacity for the red soil are also very sensitive. In phosphorus transport modelling, the exponent of equation for soil erosion processes induced by surface runoff is most sensitive, coefficient of adsorption/desorption processes for red soil is also very sensitive. Flow dynamics and water balance were simulated well at all sites for the whole period (1978-1986) with NSE≥0.80 and PBIAS≤14.53%. The optimized hydrological parameter set were transferable for the independent period (2009-2010) with NSE≥0.90 and highest PBIAS of -7.44% in stream flow simulation. Seasonal dynamics and balance of stream water TP (Total Phosphorus ) concentrations were captured satisfactorily indicated by NSE≥0.53 and highest PBIAS of 16.67%. In annual scale, most phosphorus is transported via surface runoff during heavy storm flow events, which may account for about 70% of annual TP loads. Based on future climate change analysis under three different emission

  9. 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

  10. Modeling of the jack rabbit series of experiments with a temperature based reactive burn model

    NASA Astrophysics Data System (ADS)

    Desbiens, Nicolas

    2017-01-01

    The Jack Rabbit experiments, performed by Lawrence Livermore National Laboratory, focus on detonation wave corner turning and shock desensitization. Indeed, while important for safety or charge design, the behaviour of explosives in these regimes is poorly understood. In this paper, our temperature based reactive burn model is calibrated for LX-17 and compared to the Jack Rabbit data. It is shown that our model can reproduce the corner turning and shock desensitization behaviour of four out of the five experiments.

  11. 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.

  12. Tracer experiments in periodical heterogeneous model porous medium

    NASA Astrophysics Data System (ADS)

    Majdalani, Samer; Delenne, Carole; Guinot, Vincent

    2017-06-01

    It is established that solute transport in homogenous porous media follows a classical 'S' shape breakthrough curve that can easily be modelled by a convection dispersion equation. In this study, we designed a Model Heterogeneous Porous Medium (MHPM) with a high degree of heterogeneity, in which the breakthrough curve does not follow the classical 'S' shape. The contrast in porosity is obtained by placing a cylindrical cavity (100% porosity) inside a 40% porosity medium composed with 1mm glass beads. Step tracing experiments are done by injecting salty water in the study column initially containing deionised water, until the outlet concentration stabilises to the input one. Several replicates of the experiment were conducted for n = 1 to 6 MHPM placed in series. The total of 116 experiments gives a high-quality database allowing the assessment of experimental uncertainty. The experimental results show that the breakthrough curve is very different from the `S' shape for small values of n, but the more n increases, the more the classical shape is recovered.

  13. 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

  14. 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.

  15. A curriculum model for an integrated senior year clinical experience.

    PubMed

    Wukasch, R N; Blue, C L; Overbay, J

    2000-01-01

    Transformations in the delivery of health care from hospital to community have brought about many changes in nursing practice. These, in turn, have necessitated alterations in the education of nursing students, the curricula, and clinical experiences. Confident that nursing is an independent practice, exclusive of the health care setting, our faculty decided to direct our teaching efforts to reflect changes in health care delivery. We restructured our baccalaureate nursing program's senior level clinical education experience to prepare students to meet the needs of the clients we serve--the community--and the demands of professional nursing education. In doing so, we have supported Ryan's definition of community, which includes "all settings where consumers seek health care" (1, p. 140). In response to the recommendation by the pew health professions commission for new models of content integration "between education and the highly managed and integrated systems of care" (2, p. 51), a decision was made to merge three senior level clinical courses--pediatrics, public health, and nursing leadership and management--into one integrated experience. This process required an examination of collective values and beliefs with respect to course content and learning experiences. The challenge was to examine "sacred cows" and eliminate redundancies and replication of learning activities.

  16. Thermography and machine learning techniques for tomato freshness prediction.

    PubMed

    Xie, Jing; Hsieh, Sheng-Jen; Wang, Hong-Jin; Tan, Zuojun

    2016-12-01

    The United States and China are the world's leading tomato producers. Tomatoes account for over $2 billion annually in farm sales in the U.S. Tomatoes also rank as the world's 8th most valuable agricultural product, valued at $58 billion dollars annually, and quality is highly prized. Nondestructive technologies, such as optical inspection and near-infrared spectrum analysis, have been developed to estimate tomato freshness (also known as grades in USDA parlance). However, determining the freshness of tomatoes is still an open problem. This research (1) illustrates the principle of theory on why thermography might be able to reveal the internal state of the tomatoes and (2) investigates the application of machine learning techniques-artificial neural networks (ANNs) and support vector machines (SVMs)-in combination with transient step heating, and thermography for freshness prediction, which refers to how soon the tomatoes will decay. Infrared images were captured at a sampling frequency of 1 Hz during 40 s of heating followed by 160 s of cooling. The 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 for ANN and SVM models. The ANN model built using heating and cooling data was relatively optimal. The overall regression coefficient was 0.99. These results suggest that a combination of infrared thermal imaging and ANN modeling methods can be used to predict tomato freshness with higher accuracy than SVM models.

  17. Modeling ion-induced electrons in the High Current Experiment

    SciTech Connect

    Stoltz, P.H.; Verboncoeur, J.P.; Cohen, R.H.; Molvik, A.W.; Vay, J.-L.; Veitzer, S.A.

    2006-05-15

    A primary concern for high current ion accelerators is contaminant electrons. These electrons can interfere with the beam ions, causing emittance growth and beam loss. Numerical simulation is a main tool for understanding the interaction of the ion beam with the contaminant electrons, but these simulations then require accurate models of electron generation. These models include ion-induced electron emission from ions hitting the beam pipe walls or diagnostics. However, major codes for modeling ion beam transport are written in different programming languages and used on different computing platforms. For electron generation models to be maximally useful, researchers should be able to use them easily from many languages and platforms. A model of ion-induced electrons including the electron energy distribution is presented here, including a discussion of how to use the Babel software tool to make these models available in multiple languages and how to use the GNU Autotools to make them available on multiple platforms. An application to simulation of the end region of the High Current Experiment is shown. These simulations show formation of a virtual cathode with a potential energy well of amplitude 12.0 eV, approximately six times the most probable energy of the ion-induced electrons. Oscillations of the virtual cathode could lead to possible longitudinal and transverse modulation of the density of the electrons moving out of the virtual cathode.

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

    NASA Astrophysics Data System (ADS)

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

    2008-02-01

    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. Optimal post-experiment estimation of poorly modeled dynamic systems

    NASA Technical Reports Server (NTRS)

    Mook, D. Joseph

    1988-01-01

    Recently, a novel strategy for post-experiment state estimation of discretely-measured dynamic systems has been developed. The method accounts for errors in the system dynamic model equations in a more general and rigorous manner than do filter-smoother algorithms. The dynamic model error terms do not require the usual process noise assumptions of zero-mean, symmetrically distributed random disturbances. Instead, the model error terms require no prior assumptions other than piecewise continuity. The resulting state estimates are more accurate than filters for applications in which the dynamic model error clearly violates the typical process noise assumptions, and the available measurements are sparse and/or noisy. Estimates of the dynamic model error, in addition to the states, are obtained as part of the solution of a two-point boundary value problem, and may be exploited for numerous reasons. In this paper, the basic technique is explained, and several example applications are given. Included among the examples are both state estimation and exploitation of the model error estimates.

  20. Produced water re-injection in a non-fresh water aquifer with geochemical reaction, hydrodynamic molecular dispersion and adsorption kinetics controlling: model development and numerical simulation

    NASA Astrophysics Data System (ADS)

    Obe, Ibidapo; Fashanu, T. A.; Idialu, Peter O.; Akintola, Tope O.; Abhulimen, Kingsley E.

    2016-12-01

    An improved produced water reinjection (PWRI) model that incorporates filtration, geochemical reaction, molecular transport, and mass adsorption kinetics was developed to predict cake deposition and injectivity performance in hydrocarbon aquifers in Nigeria oil fields. Thus, the improved PWRI model considered contributions of geochemical reaction, adsorption kinetics, and hydrodynamic molecular dispersion mechanism to alter the injectivity and deposition of suspended solids on aquifer wall resulting in cake formation in pores during PWRI and transport of active constituents in hydrocarbon reservoirs. The injectivity decline and cake deposition for specific case studies of hydrocarbon aquifers in Nigeria oil fields were characterized with respect to its well geometry, lithology, and calibrations data and simulated in COMSOL multiphysics software environment. The PWRI model was validated by comparisons to assessments of previous field studies based on data and results supplied by operator and regulator. The results of simulation showed that PWRI performance was altered because of temporal variations and declinations of permeability, injectivity, and cake precipitation, which were observed to be dependent on active adsorption and geochemical reaction kinetics coupled with filtration scheme and molecular dispersion. From the observed results and findings, transition time t r to cake nucleation and growth were dependent on aquifer constituents, well capacity, filtration coefficients, particle-to-grain size ratio, water quality, and more importantly, particle-to-grain adsorption kinetics. Thus, the results showed that injectivity decline and permeability damage were direct contributions of geochemical reaction, hydrodynamic molecular diffusion, and adsorption kinetics to the internal filtration mechanism, which are largely dependent on the initial conditions of concentration of active constituents of produced water and aquifer capacity.

  1. Produced water re-injection in a non-fresh water aquifer with geochemical reaction, hydrodynamic molecular dispersion and adsorption kinetics controlling: model development and numerical simulation

    NASA Astrophysics Data System (ADS)

    Obe, Ibidapo; Fashanu, T. A.; Idialu, Peter O.; Akintola, Tope O.; Abhulimen, Kingsley E.

    2017-06-01

    An improved produced water reinjection (PWRI) model that incorporates filtration, geochemical reaction, molecular transport, and mass adsorption kinetics was developed to predict cake deposition and injectivity performance in hydrocarbon aquifers in Nigeria oil fields. Thus, the improved PWRI model considered contributions of geochemical reaction, adsorption kinetics, and hydrodynamic molecular dispersion mechanism to alter the injectivity and deposition of suspended solids on aquifer wall resulting in cake formation in pores during PWRI and transport of active constituents in hydrocarbon reservoirs. The injectivity decline and cake deposition for specific case studies of hydrocarbon aquifers in Nigeria oil fields were characterized with respect to its well geometry, lithology, and calibrations data and simulated in COMSOL multiphysics software environment. The PWRI model was validated by comparisons to assessments of previous field studies based on data and results supplied by operator and regulator. The results of simulation showed that PWRI performance was altered because of temporal variations and declinations of permeability, injectivity, and cake precipitation, which were observed to be dependent on active adsorption and geochemical reaction kinetics coupled with filtration scheme and molecular dispersion. From the observed results and findings, transition time t r to cake nucleation and growth were dependent on aquifer constituents, well capacity, filtration coefficients, particle-to-grain size ratio, water quality, and more importantly, particle-to-grain adsorption kinetics. Thus, the results showed that injectivity decline and permeability damage were direct contributions of geochemical reaction, hydrodynamic molecular diffusion, and adsorption kinetics to the internal filtration mechanism, which are largely dependent on the initial conditions of concentration of active constituents of produced water and aquifer capacity.

  2. 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

  3. Modeling of and experiments on electromagnetic levitation for materials processing

    NASA Astrophysics Data System (ADS)

    Hyers, Robert W.

    Electromagnetic levitation (EML) is an important experimental technique for research in materials processing. It has been applied for many years to a wide variety of research areas, including studies of nucleation and growth, phase selection, reaction kinetics, and thermophysical property measurements. The work presented here contributes to a more fundamental understanding of three aspects of levitation systems: modeling of electromagnetic effects, modeling of fluid flow characteristics, and experiments to measure surface tension and viscosity in microgravity. In this work, the interaction between the electromagnetic field and the sample were modeled, and experiments to measure the surface tension and viscosity of liquid metal droplets were performed. The models use a 2-D axisymmetric formulation, and use the method of mutual inductances to calculate the currents induced in the sample. The magnetic flux density was calculated from the Biot-Savart law, and the force distribution obtained. Parametric studies of the total force and induced heating on the sample were carried out, as well as a study of the influence of different parameters on the internal flows in a liquid droplet. The oscillating current frequency has an important effect on the feasible operating range of an EML system. Optimization of both heating and positioning are discussed, and the use of frequencies far from those in current use for levitation of small droplets provides improved results. The dependences of the force and induced power on current, frequency, sample conductivity, and sample size are given. A model coupling the magnetic force calculations to a commercial finite-element fluid dynamics program is used to characterize the flows in a liquid sample, including transitions in the flow pattern. The dependence of fluid flow velocity on positioning force, sample viscosity, and oscillating current frequency is presented. These models were applied to the design of thermophysical property

  4. FuGE: Functional Genomics Experiment Object Model.

    PubMed

    Jones, Andrew R; Pizarro, Angel; Spellman, Paul; Miller, Michael

    2006-01-01

    This is an interim report on the Functional Genomics Experiment (FuGE) Object Model. FuGE is a framework for creating data standards for high-throughput biological experiments, developed by a consortium of researchers from academia and industry. FuGE supports rich annotation of samples, protocols, instruments, and software, as well as providing extension points for technology specific details. It has been adopted by microarray and proteomics standards bodies as a basis for forthcoming standards. It is hoped that standards developers for other omics techniques will join this collaborative effort; widespread adoption will allow uniform annotation of common parts of functional genomics workflows, reduce standard development and learning times through the sharing of consistent practice, and ease the construction of software for accessing and integrating functional genomics data.

  5. 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.

  6. 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

  7. Bounds on collapse models from cold-atom experiments

    NASA Astrophysics Data System (ADS)

    Bilardello, Marco; Donadi, Sandro; Vinante, Andrea; Bassi, Angelo

    2016-11-01

    The spontaneous localization mechanism of collapse models induces a Brownian motion in all physical systems. This effect is very weak, but experimental progress in creating ultracold atomic systems can be used to detect it. In this paper, we considered a recent experiment (Kovachy et al., 2015), where an atomic ensemble was cooled down to picokelvins. Any Brownian motion induces an extra increase of the position variance of the gas. We study this effect by solving the dynamical equations for the Continuous Spontaneous Localizations (CSL) model, as well as for its non-Markovian and dissipative extensions. The resulting bounds, with a 95 % of confidence level, are beaten only by measurements of spontaneous X-ray emission and by experiments with cantilever (in the latter case, only for rC ≥ 10-7 m, where rC is one of the two collapse parameters of the CSL model). We show that, contrary to the bounds given by X-ray measurements, non-Markovian effects do not change the bounds, for any reasonable choice of a frequency cutoff in the spectrum of the collapse noise. Therefore the bounds here considered are more robust. We also show that dissipative effects are unimportant for a large spectrum of temperatures of the noise, while for low temperatures the excluded region in the parameter space is the more reduced, the lower the temperature.

  8. 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.

  9. Models from experiments: combinatorial drug perturbations of cancer cells

    PubMed Central

    Nelander, Sven; Wang, Weiqing; Nilsson, Björn; She, Qing-Bai; Pratilas, Christine; Rosen, Neal; Gennemark, Peter; Sander, Chris

    2008-01-01

    We present a novel method for deriving network models from molecular profiles of perturbed cellular systems. The network models aim to predict quantitative outcomes of combinatorial perturbations, such as drug pair treatments or multiple genetic alterations. Mathematically, we represent the system by a set of nodes, representing molecular concentrations or cellular processes, a perturbation vector and an interaction matrix. After perturbation, the system evolves in time according to differential equations with built-in nonlinearity, similar to Hopfield networks, capable of representing epistasis and saturation effects. For a particular set of experiments, we derive the interaction matrix by minimizing a composite error function, aiming at accuracy of prediction and simplicity of network structure. To evaluate the predictive potential of the method, we performed 21 drug pair treatment experiments in a human breast cancer cell line (MCF7) with observation of phospho-proteins and cell cycle markers. The best derived network model rediscovered known interactions and contained interesting predictions. Possible applications include the discovery of regulatory interactions, the design of targeted combination therapies and the engineering of molecular biological networks. PMID:18766176

  10. Surface-wave capillary plasmas in helium: modeling and experiment

    NASA Astrophysics Data System (ADS)

    Santos, M.; Alves, L. L.; Noel, C.; Belmonte, T.

    2012-10-01

    In this paper we use both simulations and experiments to study helium discharges (99.999% purity) sustained by surface-waves (2.45 GHz frequency), in capillary tubes (3 mm radius) at atmospheric pressure. Simulations use a self-consistent homogeneous and stationary collisional-radiative model that solves the rate balance equations for the different species present in the plasma (electrons, the He^+ and He2^+ ions, the He(n<7) excited states and the He2* excimers) and the gas thermal balance equation, coupled to the two-term electron Boltzmann equation (including direct and stepwise collisions as well as electron-electron collisions). Experiments use optical emission spectroscopy diagnostics to measure the electron density (Hβ Stark broadening), the gas temperature (ro-vibrational transitions of OH, present at trace concentrations), and the populations of different excited states. Model predictions at 1.7x10^13 cm-3 electron density (within the range estimated experimentally) are in good agreement with measurements (deviations < 10%) of (i) the excitation spectrum and the excitation temperatures (2795 ± 115 K, obtained from the Boltzmann-plot of the excited state populations, with energies lying between 22.7 and 24.2 eV), (ii) the power coupled to the plasma (˜ 180 ± 10 W), and (iii) the gas temperature (˜ 1700 ± 100 K). We discuss the extreme dependence of model results (particularly the gas temperature) on the power coupled to the plasma.

  11. 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.

  12. Influence of fresh date palm co-products on the ripening of a paprika added dry-cured sausage model system.

    PubMed

    Martín-Sánchez, Ana María; Ciro-Gómez, Gelmy; Vilella-Esplá, José; Ben-Abda, Jamel; Pérez-Álvarez, José Ángel; Sayas-Barberá, Estrella

    2014-06-01

    Date palm co-products are a source of bioactive compounds that could be used as a new ingredient for the meat industry. An intermediate food product (IFP) from date palm co-products (5%) was incorporated into a paprika added dry-cured sausage (PADS) model system and was analysed for physicochemical parameters, lipid oxidation and sensory attributes during ripening. Addition of 5% IFP yielded a product with physicochemical properties similar to the traditional one. Instrumental colour differences were found, but were not detected visually by panellists, who also evaluated positively the sensory properties of the PADS with IFP. Therefore, the IFP from date palm co-products could be used as a natural ingredient in the formulation of PADS.

  13. Physical-chemical modeling of elements' behavior in mixing sea and fresh waters of minor rivers in the White Sea catchment area.

    PubMed

    Maksimova, Victoria V; Mazukhina, Svetlana I; Cherepanova, Tatiana A; Gorbacheva, Tamara T

    2017-07-29

    The physical-chemical stage of marginal filters in minor rivers of the White Sea catchment area by the example of the Umba River, flowing to Kandalaksha Gulf, has been explored. Application of the method of physical-chemical modeling on the basis of field data allowed establishing migration forms of a number of elements in the "river-sea" system and deposition of solid phases when mixing waters. The mixing of river and sea water is accompanied by the sedimentation of predominantly goethite, hydromuscovite, and hydroxylapatite. Sediments in mixing river and sea waters were found to be mainly composed by goethite, hydromuscovite, and hydroxylapatite. The research has added to the knowledge of the role of the abiotic part in the marginal filters of small rivers in the Arctic.

  14. 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

  15. 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

  16. 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.

  17. Dynamics of vortices in complex wakes: Modeling, analysis, and experiments

    NASA Astrophysics Data System (ADS)

    Basu, Saikat

    The thesis develops singly-periodic mathematical models for complex laminar wakes which are formed behind vortex-shedding bluff bodies. These wake structures exhibit a variety of patterns as the bodies oscillate or are in close proximity of one another. The most well-known formation comprises two counter-rotating vortices in each shedding cycle and is popularly known as the von Karman vortex street. Of the more complex configurations, as a specific example, this thesis investigates one of the most commonly occurring wake arrangements, which consists of two pairs of vortices in each shedding period. The paired vortices are, in general, counter-rotating and belong to a more general definition of the 2P mode, which involves periodic release of four vortices into the flow. The 2P arrangement can, primarily, be sub-classed into two types: one with a symmetric orientation of the two vortex pairs about the streamwise direction in a periodic domain and the other in which the two vortex pairs per period are placed in a staggered geometry about the wake centerline. The thesis explores the governing dynamics of such wakes and characterizes the corresponding relative vortex motion. In general, for both the symmetric as well as the staggered four vortex periodic arrangements, the thesis develops two-dimensional potential flow models (consisting of an integrable Hamiltonian system of point vortices) that consider spatially periodic arrays of four vortices with their strengths being +/-Gamma1 and +/-Gamma2. Vortex formations observed in the experiments inspire the assumed spatial symmetry. The models demonstrate a number of dynamic modes that are classified using a bifurcation analysis of the phase space topology, consisting of level curves of the Hamiltonian. Despite the vortex strengths in each pair being unequal in magnitude, some initial conditions lead to relative equilibrium when the vortex configuration moves with invariant size and shape. The scaled comparisons of the

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Electroelastic optical fiber positioning with submicrometer accuracy: Model and experiment

    NASA Astrophysics Data System (ADS)

    Kofod, Guggi; Mc Carthy, Denis N.; Krissler, Jan; Lang, Günter; Jordan, Grace

    2009-05-01

    We present accurate electromechanical measurements on a balanced push-pull dielectric elastomer actuator, demonstrating submicrometer accurate position control. An analytical model based on a simplified pure-shear dielectric elastomer film with prestretch is found to capture the voltage-displacement behavior, with reduced output due to the boundary conditions. Two complementary experiments show that actuation coefficients of 0.5-1 nm/V2 are obtainable with the demonstrated device, enabling motion control with submicrometer accuracy in a voltage range below 200 V.

  3. Radial structure of the constricted positive column: Modeling and experiment

    NASA Astrophysics Data System (ADS)

    Golubovskii, Yu.; Kalanov, D.; Maiorov, V.

    2017-08-01

    We present a detailed self-consistent model of a positive column in argon glow discharge at moderate pressures and currents. This model describes the discharge transition between diffuse and constricted states. The model includes an extensive set of plasma chemical reactions and equation for inhomogeneous gas heating. The nonequilibrium behavior of an electron distribution function is also considered. One of the main features of the model is an accurate treatment of radiation trapping by solving the Holstein-Biberman equation directly. Influence of the radiation trapping on macroscopic parameters of the constricted positive column is studied. We propose a method for solving a boundary-value problem, including particle and energy balance equations for electrons, ground state atoms, atomic and molecular ions, and excited species. Unlike traditional solution approaches for similar systems, the method provides continuous Z- and S-shaped characteristics of discharge parameters, describing hysteresis in transition between diffuse and constricted discharge regimes. Performed experiments include measurements of volt-ampere characteristics and spectroscopic study of radial density profiles of excited atoms by measuring line emission and absorption, and electrons by measuring bremsstrahlung intensity. The role of resonance radiation trapping in spatial redistribution of 1 s and 2 p states of argon is demonstrated. Results of modeling are compared to the experimental data.

  4. Experiments on fog prediction based on multi-models

    NASA Astrophysics Data System (ADS)

    Shi, C.; Wang, L.; Zhang, H.; Deng, X.

    2010-07-01

    Fog is a boundary-layer weather phenomenon with abundant water droplets or crystals that reduces visibility to less than 1 km. The low visibility on fog days usually endangers all kinds of transportation and causes huge economic losses. To numerically forecast fog, a series of numerical experiments were conducted utilizing a mesoscale meteorological model (MM5) and a one-dimension (1D) fog model (PAFOG) with detailed microphysics processes. First, the two models were coupled. MM5 provided the initial and hourly top boundary conditions (IC/BC) for PAFOG, and some other necessary input parameters, including the low, middle and high cloud covers, landuse, and geostrophic winds, etc. Thus, we can run PAFOG for any interested area. Then, the PAFOG was run using two kinds of ICs/BCs for 9 fog events observed in Nanjing during the winters of 2006 and 2007. Detailed comparisons of model results from MM5, PAFOG with two kinds of ICs/BCs for two cases with observations are presented in this paper. The results show that the couple of the two models is successful. PAFOG outperformed MM5 in simulating radiation fog; however, MM5 performed better than PAFOG in simulating advection fog. This suggests that the couple method still need to improve. The impacts of advection on fog cannot be revealed by the top boundary conditions.

  5. 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.

  6. FEM numerical model analysis of magnetic nanoparticle tumor heating experiments.

    PubMed

    Pearce, John A; Petyk, Alicia A; Hoopes, P Jack

    2014-01-01

    Iron oxide nanoparticles are currently under investigation as heating agents for hyperthermic treatment of tumors. Major determinants of effective heating include the biodistribution of magnetic materials, the minimum iron oxide loading required to achieve adequate heating, and practically achievable magnetic field strengths. These are inter-related criteria that ultimately determine the practicability of this approach to tumor treatment. Currently, we lack fundamental engineering design criteria that can be used in treatment planning and assessment. Coupling numerical models to experimental studies illuminate the underlying physical processes and can separate physical processes to determine their relative importance. Further, adding thermal damage and cell death process to the models provides valuable perspective on the likelihood of successful treatment. FEM numerical models were applied to increase the understanding of a carefully calibrated series of experiments in mouse mammary carcinoma. The numerical models results indicate that tumor loadings equivalent to approximately 1 mg of Fe3O4 per gram of tumor tissue are required to achieve adequate heating in magnetic field strengths of 34 kA/m (rms) at 160 kHz. Further, the models indicate that direct intratumoral injection of the nanoparticles results in between 1 and 20% uptake in the tissues.

  7. Constitutive modelling of brain tissue: experiment and theory.

    PubMed

    Miller, K; Chinzei, K

    1997-01-01

    Recent developments in computer-integrated and robot-aided surgery--in particular, the emergence of automatic surgical tools and robots--as well as advances in virtual reality techniques, call for closer examination of the mechanical properties of very soft tissues (such as brain, liver, kidney, etc.). The ultimate goal of our research into the biomechanics of these tissues is the development of corresponding, realistic mathematical models. This paper contains experimental results of in vitro, uniaxial, unconfined compression of swine brain tissue and discusses a single-phase, non-linear, viscoelastic tissue model. The experimental results obtained for three loading velocities, ranging over five orders of magnitude, are presented. The applied strain rates have been much lower than those applied in previous studies, focused on injury modelling. The stress-strain curves are concave upward for all compression rates containing no linear portion from which a meaningful elastic modulus might be determined. The tissue response stiffened as the loading speed increased, indicating a strong stress-strain rate dependence. The use of the single-phase model is recommended for applications in registration, surgical operation planning and training systems as well as a control system of an image-guided surgical robot. The material constants for the brain tissue are evaluated. Agreement between the proposed theoretical model and experiment is good for compression levels reaching 30% and for loading velocities varying over five orders of magnitude.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

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

    DOE PAGES

    Tilmes, S.; Mills, Mike; Niemeier, Ulrike; ...

    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

  13. APL experience with space weather modeling and transition to operations

    NASA Astrophysics Data System (ADS)

    Zanetti, L. J.; Wing, S.

    2009-12-01

    In response to the growing space weather needs, the Johns Hopkins University Applied Physics Laboratory (APL) developed and delivered twenty two state of the art space weather products under the auspice of the University Partnering in Operational Support program, initiated in 1998. These products offer nowcasts and forecasts for the region spanning from the Sun to the Earth. Some of these products have been transitioned to the Air Force Weather Agency and other space weather centers. The transition process is quite different from research modeling, requiring additional staff with different sets of expertise. Recently, APL has developed a space weather web page to serve these products to the research and user community. For the initial stage, we have chosen ten of these products to be served from our website, which is presently still under construction. APL’s experience, lessons learned, and successes from developing space weather models, the transition to operations process and the webpage access will be shared and discussed

  14. 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.

  15. 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.

  16. Island sheltering of surface gravity waves: model and experiment

    NASA Astrophysics Data System (ADS)

    Pawka, S. S.; Inman, D. L.; Guza, R. T.

    A field experiment is used to evaluate a numerical model of the sheltering of gravity waves by islands offshore of the Southern California region. The sheltering model considered here includes only the effects of island blocking and wave refraction over the island bathymetry. Wave frequency and directional spectra measured in the deep ocean (unsheltered region west of the islands) were used as input to the sheltering model and compared with coastal observations. An airborne L-band synthetic aperture radar was used to image the directional properties of the waves in the deep ocean. In addition to the unsmoothed spectra, a unimodal directional spectrum model obtained from fits to the radar spectra was also employed to suppress the high noise level of this system. Coastal measurements were made in about 10 m depth at Torrey Pines Beach with a high resolution array of pressure sensors. The model predictions and data at Torrey Pines Beach agree well in a limited frequency range (0.082 to 0.114 Hz) where the unimodal deep ocean model is appropriate. The prediction that unimodal northern swell in the deep ocean results in a bimodal directional spectrum at Torrey Pines Beach is quantitatively verified. The northern peak of the bimodal spectra is due to waves coming through the window between San Clemente and San Miguel-Santa Rosa Islands. The southerly peak is due to wave refraction over Cortez and Tanner Banks. For lower frequency waves, the effects of strong refraction in the island vicinity are shown qualitatively. Refraction can theoretically supply up to approximately 10% of the deep ocean energy that is otherwise blocked at this site. The modifications of the island shadows due to wave refraction become theoretically negligible for wave frequencies 0.11Hz. Also, local wave generation effects, which are not included in this sheltering model, are shown to be occasionally important for waves with frequencies 0.12Hz.

  17. 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

  18. 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.

  19. Influence of resuscitation fluids, fresh frozen plasma and antifibrinolytics on fibrinolysis in a thrombelastography-based, in-vitro, whole-blood model.

    PubMed

    Kostousov, Vadim; Wang, Yao-Wei W; Cotton, Bryan A; Wade, Charles E; Holcomb, John B; Matijevic, Nena

    2013-07-01

    Hyperfibrinolysis has been identified as a mechanism of trauma coagulopathy associated with poor outcome. The aim of the study was to create a trauma coagulopathy model (TCM) with a hyperfibrinolysis thrombelastography (TEG) pattern similar to injured patients and test the effects of different resuscitation fluids and antifibrinolytics on fibrinolysis. TCM was established from whole blood by either 15% dilution with isotonic saline, lactated Ringer's, Plasma-Lyte, 5% albumin, Voluven, Hextend, 6% dextran in isotonic saline or 30% dilution with lactated Ringer's plus Voluven and supplementation with tissue factor and tissue plasminogen activator (tPA). These combinations resulted in a TCM that could then be 'treated' with tranexamic acid (TXA) or 6-aminocaproic acid (ACA). Clot formation was evaluated by TEG. Whole-blood dilution by 15% with crystalloids and albumin in the presence of tissue factor plus tPA resulted in an abnormal TEG pattern and increased fibrinolysis, as did dilution with synthetic colloids. TXA 1 μg/ml or ACA 10 μg/ml were sufficient to suppress fibrinolysis when TCM was diluted 15% with lactated Ringer's, but 3 μg/ml of TXA or 30 μg/ml of ACA were needed for fibrinolysis inhibition induced by simultaneous euvolemic dilution with lactated Ringer's plus Voluven by 30%. A total of 15% dilution of whole blood in the presence of tissue factor plus tPA results in a hyperfibrinolysis TEG pattern similar to that observed in severely injured patients. Synthetic colloids worsen TEG variables with a further increase of fibrinolysis. Low concentrations of TXA or ACA reversed hyperfibrinolysis, but the efficient concentrations were dependent on the degree of fibrinolysis and whole-blood dilution.

  20. Electrode-electrolyte interface impedance: experiments and model.

    PubMed

    Bates, J B; Chu, Y T

    1992-01-01

    The impedance of the junction between a solid or aqueous electrolyte and a metal electrode at which no charge transfer processes occur (blocking contacts) follows closely the constant phase angle form, Z = A(j omega)-n, over a wide frequency range, where A is a constant, and the frequency exponent n is typically in the range of 0.7 to 0.95. Several models have been proposed in which the magnitude of the frequency exponent n is related by a simple expression to the fractal dimension d of the rough electrode surface. But experiments with aqueous H2SO4 and roughened platinum and silicon electrodes show that there is no simple relationship, if any at all, between n and d when d is determined from the analysis of one dimensional surface profiles. Moreover, n is not a simple function of the average roughness of the electrode. In order to gain some insight into the effect of electrode topography and the interface impedance, a model for the response of the interface to a constant voltage pulse was constructed. This model is based on the idea that, following a pulse, locally concentrated regions of ions accumulate rapidly at the tips of large protrusions on the electrode surface which screens deeper regions of the electrode from the field driven flux of mobile ions. After this rapid charging, ions are able to reach the deeper, screened regions of the electrode by diffusion, and it is this diffusive process that gives rise to the observed t1-n dependence of the charge collected. Computer simulations, similar to the diffusion limited aggregation model, using measured profiles as fixed (non-growing) clusters, gave exponents n in good agreement with experiment.

  1. Update on PHELIX Pulsed-Power Hydrodynamics Experiments and Modeling

    NASA Astrophysics Data System (ADS)

    Rousculp, Christopher; Reass, William; Oro, David; Griego, Jeffery; Turchi, Peter; Reinovsky, Robert; Devolder, Barbara

    2013-10-01

    The PHELIX pulsed-power driver is a 300 kJ, portable, transformer-coupled, capacitor bank capable of delivering 3-5 MA, 10 μs pulse into a low inductance load. Here we describe further testing and hydrodynamics experiments. First, a 4 nH static inductive load has been constructed. This allows for repetitive high-voltage, high-current testing of the system. Results are used in the calibration of simple circuit models and numerical simulations across a range of bank charges (+/-20 < V0 < +/-40 kV). Furthermore, a dynamic liner-on-target load experiment has been conducted to explore the shock-launched transport of particulates (diam. ~ 1 μm) from a surface. The trajectories of the particulates are diagnosed with radiography. Results are compared to 2D hydro-code simulations. Finally, initial studies are underway to assess the feasibility of using the PHELIX driver as an electromagnetic launcher for planer shock-physics experiments. Work supported by United States-DOE under contract DE-AC52-06NA25396.

  2. The Framed Standard Model (II) -- A First Test Against Experiment

    NASA Astrophysics Data System (ADS)

    Chan, Hong-Mo; Tsou, Sheung Tsun

    Apart from the qualitative features described in Paper I (Ref. 1), the renormalization group equation derived for the rotation of the fermion mass matrices are amenable to quantitative study. The equation depends on a coupling and a fudge factor and, on integration, on 3 integration constants. Its application to data analysis, however, requires the input from experiment of the heaviest generation masses mt,mb,mτ,mυ3 all of which are known, except for mυ3. Together then with the theta-angle in the QCD action, there are in all 7 real unknown parameters. Determining these 7 parameters by fitting to the experimental values of the masses mc, mυ, me, the CKM elements |Vus|, |Vub|, and the neutrino oscillation angle sin2 θ13, one can then calculate and compare with experiment the following 12 other quantities ms, mu/md, |Vud|, |Vcs|, |Vtb|, |Vcd|, |Vcb|, |Vts|, |Vtd|, J, sin2 2θ12, sin2 2θ23, and the results all agree reasonably well with data, often to within the stringent experimental error now achieved. Counting the predictions not yet measured by experiment, this means that 17 independent parameters of the standard model are now replaced by 7 in the FSM...

  3. Tough and tunable adhesion of hydrogels: experiments and models

    NASA Astrophysics Data System (ADS)

    Zhang, Teng; Yuk, Hyunwoo; Lin, Shaoting; Parada, German A.; Zhao, Xuanhe

    2017-06-01

    As polymer networks infiltrated with water, hydrogels are major constituents of animal and plant bodies and have diverse engineering applications. While natural hydrogels can robustly adhere to other biological materials, such as bonding of tendons and cartilage on bones and adhesive plaques of mussels, it is challenging to achieve such tough adhesions between synthetic hydrogels and engineering materials. Recent experiments show that chemically anchoring long-chain polymer networks of tough synthetic hydrogels on solid surfaces create adhesions tougher than their natural counterparts, but the underlying mechanism has not been well understood. It is also challenging to tune systematically the adhesion of hydrogels on solids. Here, we provide a quantitative understanding of the mechanism for tough adhesions of hydrogels on solid materials via a combination of experiments, theory, and numerical simulations. Using a coupled cohesive-zone and Mullins-effect model validated by experiments, we reveal the interplays of intrinsic work of adhesion, interfacial strength, and energy dissipation in bulk hydrogels in order to achieve tough adhesions. We further show that hydrogel adhesion can be systematically tuned by tailoring the hydrogel geometry and silanization time of solid substrates, corresponding to the control of energy dissipation zone and intrinsic work of adhesion, respectively. The current work further provides a theoretical foundation for rational design of future biocompatible and underwater adhesives.

  4. Systematic Analysis of Hollow Fiber Model of Tuberculosis Experiments.

    PubMed

    Pasipanodya, Jotam G; Nuermberger, Eric; Romero, Klaus; Hanna, Debra; Gumbo, Tawanda

    2015-08-15

    The in vitro hollow fiber system model of tuberculosis (HFS-TB), in tandem with Monte Carlo experiments, was introduced more than a decade ago. Since then, it has been used to perform a large number of tuberculosis pharmacokinetics/pharmacodynamics (PK/PD) studies that have not been subjected to systematic analysis. We performed a literature search to identify all HFS-TB experiments published between 1 January 2000 and 31 December 2012. There was no exclusion of articles by language. Bias minimization was according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Steps for reporting systematic reviews were followed. There were 22 HFS-TB studies published, of which 12 were combination therapy studies and 10 were monotherapy studies. There were 4 stand-alone Monte Carlo experiments that utilized quantitative output from the HFS-TB. All experiments reported drug pharmacokinetics, which recapitulated those encountered in humans. HFS-TB studies included log-phase growth studies under ambient air, semidormant bacteria at pH 5.8, and nonreplicating persisters at low oxygen tension of ≤ 10 parts per billion. The studies identified antibiotic exposures associated with optimal kill of Mycobacterium tuberculosis and suppression of acquired drug resistance (ADR) and informed predictions about optimal clinical doses, expected performance of standard doses and regimens in patients, and expected rates of ADR, as well as a proposal of new susceptibility breakpoints. The HFS-TB model offers the ability to perform PK/PD studies including humanlike drug exposures, to identify bactericidal and sterilizing effect rates, and to identify exposures associated with suppression of drug resistance. Because of the ability to perform repetitive sampling from the same unit over time, the HFS-TB vastly improves statistical power and facilitates the execution of time-to-event analyses and repeated event analyses, as well as dynamic system pharmacology mathematical

  5. 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.

  6. Computer modeling of a three-dimensional steam injection experiment

    SciTech Connect

    Joshi, S.; Castanier, L.M.

    1993-08-01

    The experimental results and CT scans obtained during a steam-flooding experiment with the SUPRI 3-D steam injection laboratory model are compared with the results obtained from a numerical simulator for the same experiment. Simulation studies were carried out using the STARS (Steam and Additives Reservoir Simulator) compositional simulator. The saturation and temperature distributions obtained and heat-loss rates measured in the experimental model at different stages of steam-flooding were compared with those calculated from the numerical simulator. There is a fairly good agreement between the experimental results and the simulator output. However, the experimental scans show a greater degree of gravity override than that obtained with the simulator for the same heat-loss rates. Symmetric sides of the experimental 5-spot show asymmetric heat-loss rates contrary to theory and simulator results. Some utility programs have been written for extracting, processing and outputting the required grid data from the STARS simulator. These are general in nature and can be useful for other STARS users.

  7. 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.

  8. Lattice Boltzmann modeling of directional wetting: Comparing simulations to experiments

    NASA Astrophysics Data System (ADS)

    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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Micromagnetics of Co-based media: Experiment and model (invited)

    NASA Astrophysics Data System (ADS)

    McFadyen, I. R.; Beardsley, I. A.

    1990-05-01

    The micromagnetics of Co86Cr14 thin-film longitudinal recording media has been investigated using Lorentz transmission electron microscopy, in the Fresnel and differential phase contrast (DPC) modes. The media studied were 350-Å-thick Co86Cr14 on a 200-Å Cr layer, both of which were rf sputtered onto Si3N4 membranes for ease of observation in the TEM. Different magnetization states were investigated by imaging the sample at various points in the remanent hysteresis loop. This allowed direct comparison between experimental conditions and a micromagnetic computer model which assumes the media to be an array of single-domain particles, interacting via magnetostatics and moderate integranular exchange [J.-G. Zhu and H. N. Bertram, J. Appl. Phys. 63, 3248 (1988)]. The DPC imaging technique allows vector maps and two-dimensional histograms of the integrated in-plane magnetic induction to be obtained at each magnetization state for comparison with the computer model. The scale and displacement of magnetization vortices and ripple between different states was also investigated. Both experiment and model show increasing dispersion with increasing reversal field and motion of magnetization vortices. Comparison, using the model, of individual magnetization states in an applied field and at remanence indicate a strong influence of stray fields from the media on the DPC image contrast.

  14. Ant colonies and foraging line dynamics: Modeling, experiments and computations

    NASA Astrophysics Data System (ADS)

    Rossi, Louis

    2005-11-01

    Ants are one of several types of insects that form robust and complex societies, and as such, provide rich theoretical ground for the exploration and understanding of collective dynamics and the behaviorial parameters that drive the dynamics. Many species of ants are nearly or completely blind, so they interact locally through behaviorial cues with nearby ants, and through pheromone trails left by other ants. Consistent with biological observation, two populations of ants are modeled, those seeking food and those returning to the nest with food. A simple constitutive model relating ant densities to pheromone concentrations yields a system of equations describing two interacting fluids and predicts left- and right-moving traveling waves. All the model parameters can be reduced to two Froude numbers describing the ratio between a chemical potential and the kinetic energy of the traveling ants. Laboratory experiments on Tetramorium caespitum (L) clearly indicate left and right-moving traveling density waves in agreement with the mathematical model. We focus on understanding the evolutionary utility of the traveling waves, and the optimality of the Froude numbers and other parameters.

  15. Standard Model and Beyond with Neutron Beta Decay Experiments

    NASA Astrophysics Data System (ADS)

    Liu, Jianglai

    2010-11-01

    The underlying charge-current weak interaction of the neutron beta decay connects together the Fermi constant GF, CKM matrix element Vud, the nucleon axial weak coupling constant gA, and the free neutron life time τn. Consequently, the combination of direct measurements of these provides stringent constraints to the Standard Model. At present, GF and Vud have been measured to a precision of 5 ppm and 225 ppm, respectively, whereas the data in gA and τn are less precise, and both exhibit significant inconsistency among measurements. With polarized neutrons, gA can be determined by measuring the angular correlation of the decay electrons with the neutron spin (so-called β-asymmetry). In the past, β-asymmetry have been measured in the cold neutron beam experiments, yielding a range of results much wider than the reported uncertainties. A new β-asymmetry measurement, UCNA (Ultracold Neutron Asymmetry), has been developed using the solid deuterium pulse spallation ultracold neutron (UCN) source at the Los Alamos Neutron Science Center, where UCN are transported in a guide system, fully polarized, then loaded into a decay trap within a solenoidal beta spectrometer. Utilizing UCN give this experiment very different systematics compared to cold neutron experiments. In this talk, I will give a brief review of the neutron beta decay measurements on the angular correlations as well as the life time. The main focus of this talk will be on the UCNA experiment. I will discuss the experimental techniques, and present the new results from the data in 2008 and 2009. The implication of the new results, combined with the world data on β-asymmetry, Vud, and τn, will also be discussed.

  16. Modeling experiments that simulate fragment attacks on cased munitions

    SciTech Connect

    Kerrisk, J.F.

    1996-01-01

    Roberts and Field (1993) have conducted experiments to observe the behavior of a cased high explosive (HE) charge subject to fragment attack at impact velocities below those needed for shock initiation. Two and three-dimensional hydrodynamic calculations have been done to model these experiments. Questions about the degree of confinement of the HE and about the condition of the HE during the impact were addressed. The calculations indicate that the HE was not strongly confined in this experiment, primarily due to the lateral expansion of polycarbonate blocks on the sides of the target during the impact. HE was not ejected from the hole in the casing made by the projectile up to 30 {micro}s after the impact. There are hints from these calculations of how initiation of a homogeneous sample of HE might occur in the experiment. The first involves the reshock of a small amount of HE at {approximately} 20 {micro}s as a result of the impact of the sabot on the target. The second involves the heating of the HE from plastic work during the impact. The maximum temperature rise of the HE (exclusive of the small region that was reshocked) was {approximately} 80 k. However, this is the average temperature of a region the size of a computational cell, and phenomena such as shear bands or cracks could result in higher temperatures on a smaller scale than the cell size. The third involves heating of the HE from contact with the casing material. The maximum temperature rise of the casing material from plastic work is {approximately} 870 k. This temperature occurs at the edge of a plug of casing material sheared off by the projectile. Other parts of the casing are shock heated to higher energies but may not contact the HE.

  17. Finite Element Modelling of the Apollo Heat Flow Experiments

    NASA Astrophysics Data System (ADS)

    Platt, J.; Siegler, M. A.; Williams, J.

    2013-12-01

    The heat flow experiments sent on Apollo missions 15 and 17 were designed to measure the temperature gradient of the lunar regolith in order to determine the heat flux of the moon. Major problems in these experiments arose from the fact that the astronauts were not able to insert the probes below the thermal skin depth. Compounding the problem, anomalies in the data have prevented scientists from conclusively determining the temperature dependent conductivity of the soil, which enters as a linear function into the heat flow calculation, thus stymieing them in their primary goal of constraining the global heat production of the Moon. Different methods of determining the thermal conductivity have yielded vastly different results resulting in downward corrections of up to 50% in some cases from the original calculations. Along with problems determining the conductivity, the data was inconsistent with theoretical predictions of the temperature variation over time, leading some to suspect that the Apollo experiment itself changed the thermal properties of the localised area surrounding the probe. The average temperature of the regolith, according to the data, increased over time, a phenomenon that makes calculating the thermal conductivity of the soil and heat flux impossible without knowing the source of error and accounting for it. The changes, possibly resulting from as varied sources as the imprint of the Astronauts boots on the lunar surface, compacted soil around the bore stem of the probe or even heat radiating down the inside of the tube, have convinced many people that the recorded data is unusable. In order to shed some light on the possible causes of this temperature rise, we implemented a finite element model of the probe using the program COMSOL Multi-physics as well as Matlab. Once the cause of the temperature rise is known then steps can be taken to account for the failings of the experiment and increase the data's utility.

  18. 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

  19. 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.

  20. Galton-Watson Models for Townsend Discharge Experiments

    NASA Astrophysics Data System (ADS)

    Cap, Daniel Michael

    Under normal circumstances, a gas is almost a perfect insulator. However, if a sufficiently large potential difference is applied to a pair of electrodes immersed in a gas, then an instability is induced where the gas changes state and becomes an excellent electrical conductor. This instability is known as electrical breakdown, and information about avoiding or stimulating its occurrence is critical to the design and operation of many technological systems. Since the turn of the century, scientists and engineers have used Townsend discharges to study the relationship between electrical breakdown and the underlying physical processes. Mathematical models for Townsend discharge experiments are developed in this work that incorporate ideas drawn from the theory of branching processes. The models are constructed by using probability notions and language to describe the physical phenomena that occur. For example, the method of first passage (renewal argument) is used to derive an integral equation for the generating function of an electron avalanche. And the electron regeneration that occurs at the cathode, due to collection of photons and positive ions produced by the avalanche, is modeled as a compound stochastic process. Most of the results of interest are obtained either by manipulating generating functions or by applying the extinction probably and total progeny theorems of Galton-Watson branching processes. The resulting mathematical models are stochastic generalizations of the deterministic descriptions that are normally used in the analysis of Townsend discharge experiments. These new models have two practical uses. They provide alternative methods for estimating the Townsend ionization coefficients, based on measuring the waiting time until breakdown or the total charge collected by the anode when a single progenitor is released from the cathode, that can be compared with results obtained by the classical current multiplication method. Since the primary and

  1. Thermodynamic model of Mars Oxygen ISRU Experiment (MOXIE)

    NASA Astrophysics Data System (ADS)

    Meyen, Forrest E.; Hecht, Michael H.; Hoffman, Jeffrey A.

    2016-12-01

    As humankind expands its footprint in the solar system, it is increasingly important to make use of the resources already in our solar system to make these missions economically feasible and sustainable. In-Situ Resource Utilization (ISRU), the science of using resources at a destination to support exploration missions, unlocks potential destinations by significantly reducing the amount of resources that need to be launched from Earth. Carbon dioxide is an example of an in-situ resource that comprises 96% of the Martian atmosphere and can be used as a source of oxygen for propellant and life support systems. The Mars Oxygen ISRU Experiment (MOXIE) is a payload being developed for NASA's upcoming Mars 2020 rover. MOXIE will produce oxygen from the Martian atmosphere using solid oxide electrolysis (SOXE). MOXIE is on the order of magnitude of a 1% scale model of an oxygen processing plant that might enable a human expedition to Mars in the 2030s through the production of the oxygen needed for the propellant of a Mars ascent vehicle. MOXIE is essentially an energy conversion system that draws energy from the Mars 2020 rover's radioisotope thermoelectric generator and ultimately converts it to stored energy in oxygen and carbon monoxide molecules. A thermodynamic model of this novel system is used to understand this process in order to derive operating parameters for the experiment. This paper specifically describes the model of the SOXE component. Assumptions and idealizations are addressed, including 1D and 2D simplifications. Operating points are discussed as well as impacts of flow rates and production.

  2. 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.

  3. A first test of the framed standard model against experiment

    NASA Astrophysics Data System (ADS)

    Bordes, José; Chan, Hong-Mo; Tsou, Sheung Tsun

    2015-04-01

    The framed standard model (FSM) is obtained from the standard model by incorporating, as field variables, the frame vectors (vielbeins) in internal symmetry space. It gives the standard Higgs boson and 3 generations of quarks and leptons as immediate consequences. It gives moreover a fermion mass matrix of the form: m = mTαα†, where α is a vector in generation space independent of the fermion species and rotating with changing scale, which has already been shown to lead, generically, to up-down mixing, neutrino oscillations and mass hierarchy. In this paper, pushing the FSM further, one first derives to 1-loop order the RGE for the rotation of α, and then applies it to fit mass and mixing data as a first test of the model. With 7 real adjustable parameters, 18 measured quantities are fitted, most (12) to within experimental error or to better than 0.5 percent, and the rest (6) not far off. (A summary of this fit can be found in Table 2 of this paper.) Two notable features, both generic to FSM, not just specific to the fit, are: (i) that a theta-angle of order unity in the instanton term in QCD would translate via rotation into a Kobayashi-Maskawa phase in the CKM matrix of about the observed magnitude (J 10-5), (ii) that it would come out correctly that mu < md, despite the fact that mt ≫ mb, mc ≫ ms. Of the 18 quantities fitted, 12 are deemed independent in the usual formulation of the standard model. In fact, the fit gives a total of 17 independent parameters of the standard model, but 5 of these have not been measured by experiment.

  4. The mechanics of neutrophils: synthetic modeling of three experiments.

    PubMed

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

    2003-05-01

    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

  5. 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

  6. Microcosm Experiments and Modeling of Microbial Movement Under Unsaturated Conditions

    SciTech Connect

    Brockman, F.J.; Kapadia, N.; Williams, G.; Rockhold, M.

    2006-04-05

    Colonization of bacteria in porous media has been studied primarily in saturated systems. In this study we examine how microbial colonization in unsaturated porous media is controlled by water content and particle size. This is important for understanding the feasibility and success of bioremediation via nutrient delivery when contaminant degraders are at low densities and when total microbial populations are sparse and spatially discontinuous. The study design used 4 different sand sizes, each at 4 different water contents; experiments were run with and without acetate as the sole carbon source. All experiments were run in duplicate columns and used the motile organism Pseudomonas stutzeri strain KC, a carbon tetrachloride degrader. At a given sand size, bacteria traveled further with increasing volumetric water content. At a given volumetric water content, bacteria generally traveled further with increasing sand size. Water redistribution, solute transport, gas diffusion, and bacterial colonization dynamics were simulated using a numerical finite-difference model. Solute and bacterial transport were modeled using advection-dispersion equations, with reaction rate source/sink terms to account for bacterial growth and substrate utilization, represented using dual Monod-type kinetics. Oxygen transport and diffusion was modeled accounting for equilibrium partitioning between the aqueous and gas phases. The movement of bacteria in the aqueous phase was modeled using a linear impedance model in which the term D{sub m} is a coefficient, as used by Barton and Ford (1995), representing random motility. The unsaturated random motility coefficients we obtained (1.4 x 10{sup -6} to 2.8 x 10{sup -5} cm{sup 2}/sec) are in the same range as those found by others for saturated systems (3.5 x 10{sup -6} to 3.5 x 10{sup -5} cm{sup 2}/sec). The results show that some bacteria can rapidly migrate in well sorted unsaturated sands (and perhaps in relatively high porosity, poorly

  7. A global parallel model based design of experiments method to minimize model output uncertainty.

    PubMed

    Bazil, Jason N; Buzzard, Gregory T; Rundell, Ann E

    2012-03-01

    Model-based experiment design specifies the data to be collected that will most effectively characterize the biological system under study. Existing model-based design of experiment algorithms have primarily relied on Fisher Information Matrix-based methods to choose the best experiment in a sequential manner. However, these are largely local methods that require an initial estimate of the parameter values, which are often highly uncertain, particularly when data is limited. In this paper, we provide an approach to specify an informative sequence of multiple design points (parallel design) that will constrain the dynamical uncertainty of the biological system responses to within experimentally detectable limits as specified by the estimated experimental noise. The method is based upon computationally efficient sparse grids and requires only a bounded uncertain parameter space; it does not rely upon initial parameter estimates. The design sequence emerges through the use of scenario trees with experimental design points chosen to minimize the uncertainty in the predicted dynamics of the measurable responses of the system. The algorithm was illustrated herein using a T cell activation model for three problems that ranged in dimension from 2D to 19D. The results demonstrate that it is possible to extract useful information from a mathematical model where traditional model-based design of experiments approaches most certainly fail. The experiments designed via this method fully constrain the model output dynamics to within experimentally resolvable limits. The method is effective for highly uncertain biological systems characterized by deterministic mathematical models with limited data sets. Also, it is highly modular and can be modified to include a variety of methodologies such as input design and model discrimination.

  8. Model Experiment on the Temporary Closure of a Breached Bank

    NASA Astrophysics Data System (ADS)

    Shimada, T.; Maeda, S.; Nakashima, Y.

    2016-12-01

    In recent years, the possibility of river bank failures has been rising due to increased occurrences of floods from localized torrential downpours and typhoons. To mitigate bank failure damage, we made an experiment to simulate the flood discharge reduction effect of a temporary closure at an opening in a breached bank. A scale river model was used. A bank was made and then breached. Then, model blocks were placed to close the breach, to observe the flood discharge reduction afforded by the closure. We assumed that the blocks would be placed by a crane or from a helicopter, so we placed the model blocks accordingly. Regardless of the placement method, the flood discharge reduction was about 20% when about 50% of the breach was closed by the placement of blocks starting from the upstream-most portion of the breach. That result was because the water flow hit the tip of the placed closure, scoured the bed near the tip, and lowered the bed at the remaining part of the breach opening, after which the area where water flows out did not decrease at the same rate as the rate of longitudinal closure for the breach. In addition, with each successive length of breach closure, the required number of blocks increased and the closure progress decreased, because of the bed degradation. The results show that it is possible to reduce the flood flow from a bank breach effectively while closing the opening by taking measures to reduce bed scouring near the breach.

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

    PubMed

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

    2014-05-05

    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.

  10. 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.

  11. Failed oceanic transform models: experience of shaking the tree

    NASA Astrophysics Data System (ADS)

    Gerya, Taras

    2017-04-01

    In geodynamics, numerical modeling is often used as a trial-and-error tool, which does not necessarily requires full understanding or even a correct concept for a modeled phenomenon. Paradoxically, in order to understand an enigmatic process one should simply try to model it based on some initial assumptions, which must not even be correct… The reason is that our intuition is not always well "calibrated" for understanding of geodynamic phenomena, which develop on space- and timescales that are very different from our everyday experience. We often have much better ideas about physical laws governing geodynamic processes than on how these laws should interact on geological space- and timescales. From this prospective, numerical models, in which these physical laws are self-consistently implemented, can gradually calibrate our intuition by exploring what scenarios are physically sensible and what are not. I personally went through this painful learning path many times and one noteworthy example was my 3D numerical modeling of oceanic transform faults. As I understand in retrospective, my initial literature-inspired concept of how and why transform faults form and evolve was thermomechanically inconsistent and based on two main assumptions (btw. both were incorrect!): (1) oceanic transforms are directly inherited from the continental rifting and breakup stages and (2) they represent plate fragmentation structures having peculiar extension-parallel orientation due to the stress rotation caused by thermal contraction of the oceanic lithosphere. During one year (!) of high-resolution thermomechanical numerical experiments exploring various physics (including very computationally demanding thermal contraction) I systematically observed how my initially prescribed extension-parallel weak transform faults connecting ridge segments rotated away from their original orientation and get converted into oblique ridge sections… This was really an epic failure! However, at the

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

    USDA-ARS?s Scientific Manuscript database

    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...

  13. [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

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

    USDA-ARS?s Scientific Manuscript database

    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 ...

  15. Pork loin quality is not indicative of fresh belly or fresh and cured ham quality

    USDA-ARS?s Scientific Manuscript database

    The objective was to characterize the relationship between fresh 30 loin quality and with fresh belly or fresh and cured ham quality. Pigs raised in 8 barns representing two seasons [cold (n = 4,290) and hot (n = 3,394)] and two production focuses [lean (n = 3,627) and quality n = 4,057)] were used....

  16. 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.

  17. 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.

  18. Atomic detection in microwave cavity experiments: A dynamical model

    SciTech Connect

    Rossi, R. Jr.; Nemes, M. C.; Peixoto de Faria, J. G.

    2007-06-15

    We construct a model for the atomic detection in the context of cavity quantum electrodynamics (QED) used to study coherence properties of superpositions of states of an electromagnetic mode. Analytic expressions for the atomic ionization are obtained, considering the imperfections of the measurement process due to the probabilistic nature of the interactions between the ionization field and the atoms. We provide for a dynamical content for the available expressions for the counting rates considering limited efficiency of detectors. Moreover, we include false countings. The influence of these imperfections on the information about the state of the cavity mode is obtained. In order to test the adequacy of our approach, we investigate a recent experiment reported by Maitre [X. Maitre et al., Phys. Rev. Lett. 79, 769 (1997)] and we obtain excellent agreement with the experimental results.

  19. Three-dimensional antenna models for fusion experiments

    NASA Astrophysics Data System (ADS)

    Carter, M. D.; Wang, C. Y.; Hogan, J. T.; Harris, J. H.; Hoffman, D. J.; Rasmussen, D. A.; Ryan, P. M.; Stallings, D. S.; Batchelor, D. B.; Beaumont, B.; Hutter, T.; Saoutic, B.

    1996-02-01

    The development of the RANT3D code has permitted the systematic study of the effect of three-dimensional structures on the launched power spectrum for antennas in the ion cyclotron range of frequencies. The code allows the septa between current straps to be modeled with arbitrary heights and permits the antenna to interact with other structures in the tokamak. In this paper we present comparisons of calculated loading with the Tokamak Fusion Test Reactor and Tore Supra experiments, demonstrate the effects on loading caused by positioning uncertainties for an antenna in Tore Supra, and show electric field patterns near the Tore Supra antenna. A poloidal component in the static magnetic field for the plasma response is included in the near-field calculations using the warm plasma code, GLOSI. Preliminary estimates for the heat flux on the bumper limiters during typical operation in Tore Supra are also presented.

  20. 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...

  1. 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.

  2. How Magnus Bends the Flying Ball - Experimenting and Modeling

    NASA Astrophysics Data System (ADS)

    Timková, V.; Ješková, Z.

    2017-02-01

    Students are well aware of the effect of the deflection of sports balls when they have been given a spin. A volleyball, tennis, or table tennis ball served with topspin results in an additional downward force that makes the ball difficult to catch and return. In soccer, the effect of sidespin causes the ball to curve unexpectedly sideways, resulting in a so-called banana kick that can confuse the goalkeeper. These surprising effects attract students' attention such that the motion of sports balls can be used to capture the interest of students towards the physics behind it. However, to study and analyze the motion of a real ball kicked in a playfield is not an easy task. Instead of the large-scale full-size sports ball motion, there can be designed and studied simpler experiments that can be carried out in the classroom. Moreover, digital technologies that are available at schools enable students to collect data from the experiment easily in a reasonable time. The mathematical model based on the analysis of forces acting on the ball flying in the air can be used to simulate the motion in order to understand the basic physical principles of the motion so that the best correspondence may be found.

  3. 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.

  4. 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.

  5. Modeling Hohlraum-Based Laser Plasma Instability Experiments

    NASA Astrophysics Data System (ADS)

    Meezan, N. B.

    2005-10-01

    Laser fusion targets must control laser-plasma instabilities (LPI) in order to perform as designed. We present analyses of recent hohlraum LPI experiments from the Omega laser facility. The targets, gold hohlraums filled with gas or SiO2 foam, are preheated by several 3φ beams before an interaction beam (2φ or 3φ) is fired along the hohlraum axis. The experiments are simulated in 2-D and 3-D using the code hydra. The choice of electron thermal conduction model in hydra strongly affects the simulated plasma conditions. This work is part of a larger effort to systematically explore the usefulness of linear gain as a design tool for fusion targets. We find that the measured Raman and Brillouin backscatter scale monotonically with the peak linear gain calculated for the target; however, linear gain is not sufficient to explain all trends in the data. This work was performed under the auspices of the U.S. Department of Energy by the University of California Lawrence Livermore National Laboratory under contract No. W-7405-ENG-48.

  6. 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.

  7. Decision dynamics of departure times: Experiments and modeling

    NASA Astrophysics Data System (ADS)

    Sun, Xiaoyan; Han, Xiao; Bao, Jian-Zhang; Jiang, Rui; Jia, Bin; Yan, Xiaoyong; Zhang, Boyu; Wang, Wen-Xu; Gao, Zi-You

    2017-10-01

    A fundamental problem in traffic science is to understand user-choice behaviors that account for the emergence of complex traffic phenomena. Despite much effort devoted to theoretically exploring departure time choice behaviors, relatively large-scale and systematic experimental tests of theoretical predictions are still lacking. In this paper, we aim to offer a more comprehensive understanding of departure time choice behaviors in terms of a series of laboratory experiments under different traffic conditions and feedback information provided to commuters. In the experiment, the number of recruited players is much larger than the number of choices to better mimic the real scenario, in which a large number of commuters will depart simultaneously in a relatively small time window. Sufficient numbers of rounds are conducted to ensure the convergence of collective behavior. Experimental results demonstrate that collective behavior is close to the user equilibrium, regardless of different scales and traffic conditions. Moreover, the amount of feedback information has a negligible influence on collective behavior but has a relatively stronger effect on individual choice behaviors. Reinforcement learning and Fermi learning models are built to reproduce the experimental results and uncover the underlying mechanism. Simulation results are in good agreement with the experimentally observed collective behaviors.

  8. 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.

  9. Experiments and modeling of iron-particle-filled magnetorheological elastomers

    NASA Astrophysics Data System (ADS)

    Danas, K.; Kankanala, S. V.; Triantafyllidis, N.

    2012-01-01

    Magnetorheological elastomers (MREs) are ferromagnetic particle impregnated rubbers whose mechanical properties are altered by the application of external magnetic fields. Due to their coupled magnetoelastic response, MREs are finding an increasing number of engineering applications. In this work, we present a combined experimental and theoretical study of the macroscopic response of a particular MRE consisting of a rubber matrix phase with spherical carbonyl iron particles. The MRE specimens used in this work are cured in the presence of strong magnetic fields leading to the formation of particle chain structures and thus to an overall transversely isotropic composite. The MRE samples are tested experimentally under uniaxial stresses as well as under simple shear in the absence or in the presence of magnetic fields and for different initial orientations of their particle chains with respect to the mechanical and magnetic loading direction. Using the theoretical framework for finitely strained MREs introduced by Kankanala and Triantafyllidis (2004), we propose a transversely isotropic energy density function that is able to reproduce the experimentally measured magnetization, magnetostriction and simple shear curves under different prestresses, initial particle chain orientations and magnetic fields. Microscopic mechanisms are also proposed to explain (i) the counterintuitive effect of dilation under zero or compressive applied mechanical loads for the magnetostriction experiments and (ii) the importance of a finite strain constitutive formulation even at small magnetostrictive strains. The model gives an excellent agreement with experiments for relatively moderate magnetic fields but has also been satisfactorily extended to include magnetic fields near saturation.

  10. Dynamical experiments on models of colliding disk galaxies

    NASA Technical Reports Server (NTRS)

    Gerber, Richard A.; Balsara, Dinshaw S.; Lamb, Susan A.

    1990-01-01

    Collisions between galaxies can induce large morphological changes in the participants and, in the case of colliding disk galaxies, bridges and tails are often formed. Observations of such systems indicate a wide variation in color (see Larson and Tinsley, 1978) and that some of the particpants are experiencing enhanced rates of star formation, especially in their central regions (Bushouse 1986, 1987; Kennicutt et al., 1987, Bushouse, Lamb, and Werner, 1988). Here the authors describe progress made in understanding some of the dynamics of interacting galaxies using N-body stellar dynamical computer experiments, with the goal of extending these models to include a hydrodynamical treatment of the gas so that a better understanding of globally enhanced star formation will eventually be forthcoming. It was concluded that close interactions between galaxies can produce large perturbations in both density and velocity fields. The authors measured, via computational experiments that represent a galaxy's stars, average radial velocity flows as large as 100 km/sec and 400 percent density increases. These can occur in rings that move outwards through the disk of a galaxy, in roughly homologous inflows toward the nucleus, and in off center, non-axisymmetric regions. Here the authors illustrate where the gas is likely to flow during the early stages of interaction and in future work they plan to investigate the fate of the gas more realistically by using an N-body/Smoothed Particle Hydrodynamics code to model both the stellar and gaseous components of a disk galaxy during a collision. Specifically, they will determine the locations of enhanced gas density and the strength and location of shock fronts that form during the interaction.

  11. Structure Modeling and Validation applied to Source Physics Experiments (SPEs)

    NASA Astrophysics Data System (ADS)

    Larmat, C. S.; Rowe, C. A.; Patton, H. J.

    2012-12-01

    The U. S. Department of Energy's Source Physics Experiments (SPEs) comprise a series of small chemical explosions used to develop a better understanding of seismic energy generation and wave propagation for low-yield explosions. In particular, we anticipate improved understanding of the processes through which shear waves are generated by the explosion source. Three tests, 100, 1000 and 1000 kg yields respectively, were detonated in the same emplacement hole and recorded on the same networks of ground motion sensors in the granites of Climax Stock at the Nevada National Security Site. We present results for the analysis and modeling of seismic waveforms recorded close-in on five linear geophone lines extending radially from ground zero, having offsets from 100 to 2000 m and station spacing of 100 m. These records exhibit azimuthal variations of P-wave arr