Science.gov

Sample records for l2-5 experiment comparison

  1. Assessment of RELAP5/MOD2, Cycle 36-04 using LOFT (Loss of Fluid Test) Large Break Experiment L2-5

    SciTech Connect

    Bank, Young Seok; Lee, Sang Yong; Kim, Hho-Jung . Korea Nuclear Safety Center)

    1990-04-01

    The LOFT L2-5 LBLOCA Experiment was simulated using the RELAP5/MOD2 Cycle 36.04 code to assess its capability to predict the phenomena in LBLOCA. One base case calculation and three cases of different nodalizations were carried out. The effect of different nodalization was studied in the area of the downcomer and core. For a sensitivity study, another calculation was executed using an updated version of RELAP5/MOD2 Cycle 36.04. A Split downcomer with one crossflow junction and two core channels were found to be effective in describing the ECC bypass and hot channel behavior. And the updated version was found to be effective in overcoming the code deficiency in the interfacial friction and reflood quenching. 11 refs., 55 figs., 10 tabs.

  2. Group membership and everyday social comparison experiences

    PubMed Central

    SMITH, HEATHER J.; LEACH, COLIN W.

    2006-01-01

    In two everyday experience studies, we examined the degree to which everyday social comparisons are framed by group membership. In the first study, 30 undergraduates attending a public university in the United States completed short questionnaires about their social comparison experiences whenever they were signalled. In the second study, 34 ethnic minority undergraduates from the same university completed similar questionnaires about their social comparison experiences. Across both studies, comparisons in which participants viewed themselves as an ingroup member in comparison to an outgroup comprised less than 10% of the comparison experiences reported by participants. However, minorities in the second study who reported closer identification with their ethnic group reported more comparison experiences in which they mentioned their own or the comparison target's ethnicity. PMID:16691290

  3. 33alloy: comparison between experiment and simulation

    SciTech Connect

    Kramer, M J; Mendelev, M I; Asta, M

    2014-04-22

    We report data on the structure of liquid Al and an Al67Mg33 alloy obtained from state-of-the-art X-ray diffraction experiments and ab initio molecular dynamics (AIMD) simulations. To facilitate a direct comparison between these data, we develop a method to elongate the AIMD pair correlation function in order to obtain reliable AIMD structure factors. The comparison reveals an appreciable level of discrepancy between experimental and AIMD liquid structures, with the latter being consistently more ordered than the former at the same temperature. The discrepancy noted in this study is estimated to have significant implications for simulation-based calculations of liquid transport properties and solid–liquid interface kinetic properties.

  4. Comparison of bioseparation methods for microgravity experiments

    NASA Technical Reports Server (NTRS)

    Morrison, Dennis R.; Cohly, Hari H. P.; Rodkey, L. Scott; Barlow, Grant H.; Hymer, Wesley C.

    1988-01-01

    The efficiency of the 1-g version of the continuous-flow electrophoresis (CFE) system flown on Space Shuttle missions is compared with the efficiency of a commercial CFE for separating living cells (human kidney, liver, and pituitary-gland cells and T-lymphocytes). In addition, the CFE system and a reciprocal isoelectric focusing (RIEF) system are compared with respect to protein pyrification efficiency. Correlations were made among electrophoretic mobilities (EPMs), secretory functions of cells, and input sample concentrations. A significant reduction in mean and range EPM was observed when input sample concentrations exceeded a low threshohold. This effect was not observed in microgravity experiments conducted at sample concentrations three times greater than the threshold for the controls. Comparison of CFE and RIEF methods showed that there are apparent advantages for each method depending on the product. For example, RIEF purification of urokinase removed more protein impurities, but focused the enzyme at a pH different than the enzyme's known isoelectric point.

  5. OpenMP Experiences and Comparisons

    NASA Technical Reports Server (NTRS)

    Nelson, Terry; Thigpen, William W. (Technical Monitor)

    2002-01-01

    The document discusses message passage interfaces (MPI), open message passage issues and parallelization. A comparison of the two vector platforms, C90 and SVlex is presented. Sections of the document are written in computer code.

  6. GASFLOW comparisons with bureau of mines experiments

    SciTech Connect

    Mueller, C.; Travis, J.R.

    1994-09-01

    At the request of the Department of Energy and Westinghouse Hanford Company, the Bureau of Mines has investigated the flammability of mixtures of hydrogen, ammonia, nitrous oxide, and air. The tests were performed in a spherical chamber under quiescent and turbulent conditions. This paper describes combustion calculations using the GASFLOW code and compares the calculated pressure ratios with experiments mentioned above. GASFLOW is a finite-volume computer code that solves the transient, three-dimensional, compressible fluid, Navier-Stokes equations with multiple species coupled with finite-rate chemical kinetics. The computational results show good agreement with the experimental data and confirm GASFLOW to be a valuable tool for evaluating the above combustion process.

  7. Disentangling forms of Lorentz violation with complementary clock comparison experiments

    SciTech Connect

    Altschul, Brett

    2009-03-15

    Atomic clock comparisons provide some of the most precise tests of Lorentz and CPT symmetries in the laboratory. With data from multiple such experiments using different nuclei, it is possible to constrain new regions of the parameter space for Lorentz violation. Relativistic effects in the nuclei allow us to disentangle forms of Lorentz violation which could not be separately measured in purely nonrelativistic experiments. The disentangled bounds in the neutron sectors are at the 10{sup -28} GeV level, far better than could be obtained with any other current technique.

  8. Comparison of simulation with experiment in an RFQ

    SciTech Connect

    Boicourt, G.P.; Sander, O.R.; Wangler, T.P.

    1985-01-01

    The accelerator test stand (ATS) RFQ has provided an opportunity to compare the predictions of the RFQ beam-dynamics code PARMTEQ with actual operation of an RFQ. For this comparison, the code was adapted to simulate the measured operation parameters, which are somewhat different from those of the ideal design. A Monte Carlo code was written to provide input to PARMTEQ, based on measured input beam distributions. With these refinements, the code has given results that are in good agreement with measurements and has provided information leading to an explanation of an unexpected set of measurements. This paper describes the method used to generate a pseudo particle beam based on the measured transverse properties of the RFQ input beam and describes some of the comparisons between simulation and experiment. An explanation is provided for the energy-spectrum structure observed in the RFQ output beam during low-voltage operation. 3 refs., 7 figs.

  9. Experience with CANDID: Comparison algorithm for navigating digital image databases

    SciTech Connect

    Kelly, P.; Cannon, M.

    1994-10-01

    This paper presents results from the authors experience with CANDID (Comparison Algorithm for Navigating Digital Image Databases), which was designed to facilitate image retrieval by content using a query-by-example methodology. A global signature describing the texture, shape, or color content is first computed for every image stored in a database, and a normalized similarity measure between probability density functions of feature vectors is used to match signatures. This method can be used to retrieve images from a database that are similar to a user-provided example image. Results for three test applications are included.

  10. Experience with CANDID: comparison algorithm for navigating digital image databases

    NASA Astrophysics Data System (ADS)

    Kelly, Patrick M.; Cannon, T. Michael

    1995-01-01

    This paper presents results from our experience with CANDID (comparison algorithm for navigating digital image databases), which was designed to facilitate image retrieval by content using a query-by-example methodology. A global signature describing the texture, shape, or color content is first computed for every image stored in a database, and a normalized similarity measure between probability density functions of feature vectors is used to match signatures. This method can be used to retrieve images from a database that are similar to a user-provided example image. Results for three test applications are included.

  11. Initial NIF Shock Timing Experiments: Comparison with Simulation

    NASA Astrophysics Data System (ADS)

    Robey, H. F.; Celliers, P. M.; Boehly, T. R.; Datte, P. S.; Bowers, M. W.; Olson, R. E.; Munro, D. H.; Milovich, J. L.; Jones, O. S.; Nikroo, A.; Kroll, J. J.; Horner, J. B.; Hamza, A. V.; Bhandarkar, S. D.; Giraldez, E.; Castro, C.; Gibson, C. R.; Eggert, J. H.; Smith, R. F.; Park, H.-S.; Young, B. K.; Hsing, W. W.; Landen, O. L.; Meyerhofer, D. D.

    2010-11-01

    Initial experiments are underway to demonstrate the techniques required to tune the shock timing of capsule implosions on the National Ignition Facility (NIF). These experiments use a modified cryogenic hohlraum geometry designed to precisely match the performance of ignition hohlraums. The targets employ a re-entrant Au cone to provide optical access to the shocks as they propagate in the liquid deuterium-filled capsule interior. The strength and timing of the shocks is diagnosed with VISAR (Velocity Interferometer System for Any Reflector) and DANTE. The results of these measurements will be used to set the precision pulse shape for ignition capsule implosions to follow. Experimental results and comparisons with numerical simulation are presented.

  12. Results from the International Halocarbons in Air Comparison Experiment (IHALACE)

    NASA Astrophysics Data System (ADS)

    Hall, B. D.; Engel, A.; Mühle, J.; Elkins, J. W.; Artuso, F.; Atlas, E.; Aydin, M.; Blake, D.; Brunke, E.-G.; Chiavarini, S.; Fraser, P. J.; Happell, J.; Krummel, P. B.; Levin, I.; Loewenstein, M.; Maione, M.; Montzka, S. A.; O'Doherty, S.; Reimann, S.; Rhoderick, G.; Saltzman, E. S.; Scheel, H. E.; Steele, L. P.; Vollmer, M. K.; Weiss, R. F.; Worthy, D.; Yokouchi, Y.

    2014-02-01

    The International Halocarbons in Air Comparison Experiment (IHALACE) was conducted to document relationships between calibration scales among various laboratories that measure atmospheric greenhouse and ozone depleting gases. This study included trace gases such as chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and hydrofluorocarbons (HFCs), as well as nitrous oxide, methane, sulfur hexafluoride, very short-lived halocompounds, and carbonyl sulfide. Many of these gases are present in the unpolluted atmosphere at pmol mol-1 (parts per trillion) or nmol mol-1 (parts per billion) levels. Six stainless steel cylinders containing natural and modified natural air samples were circulated among 19 laboratories. Results from this experiment reveal relatively good agreement (within a few percent) among commonly used calibration scales. Scale relationships for some gases, such as CFC-12 and CCl4, were found to be consistent with those derived from estimates of global mean mole fractions, while others, such as halon-1211 and CH3Br, revealed discrepancies. The transfer of calibration scales among laboratories was problematic in many cases, meaning that measurements tied to a particular scale may not, in fact, be compatible. Large scale transfer errors were observed for CH3CCl3 (10-100%) and CCl4 (2-30%), while much smaller scale transfer errors (< 1%) were observed for halon-1211, HCFC-22, and HCFC-142b. These results reveal substantial improvements in calibration over previous comparisons. However, there is room for improvement in communication and coordination of calibration activities with respect to the measurement of halogenated and related trace gases.

  13. Contact line instability: Comparison between experiments and numerical simulations

    NASA Astrophysics Data System (ADS)

    Diez, J.; González, A. G.; Gomba, J.; Gratton, R.; Kondic, Lou

    2003-11-01

    We report results of experiments and numerical simulations of the spreading of fixed volumes of silicon oil on vertical substrates. The initial condition is generated from a filament of diameter 0.4 mm and cross section of 10-4 cm^2. By means of two optical techniques, the Schlieren method and the use of an anamorphic lens, we performed a systematic study for a range of cross sections. In particular, we measure the thickness during the early stable stage of the spreading, and analyze the spatial Fourier spectra of the shape of the contact line in the unstable stage, which leads to a finger shaped pattern. The experimental results are compared with numerical simulations within the framework of lubrication approximation. The good agreement found between experiments and simulations strongly supports the hypotheses of the theory and the methods employed in the numerical calculations. This comparison is essential to determine the realistic thickness of the precursor film that must be used in the simulations. Its value (≈ 40 nm) is consistent with measurements in the literature.

  14. Extension of nanoconfined DNA: Quantitative comparison between experiment and theory

    NASA Astrophysics Data System (ADS)

    Iarko, V.; Werner, E.; Nyberg, L. K.; Müller, V.; Fritzsche, J.; Ambjörnsson, T.; Beech, J. P.; Tegenfeldt, J. O.; Mehlig, K.; Westerlund, F.; Mehlig, B.

    2015-12-01

    The extension of DNA confined to nanochannels has been studied intensively and in detail. However, quantitative comparisons between experiments and model calculations are difficult because most theoretical predictions involve undetermined prefactors, and because the model parameters (contour length, Kuhn length, effective width) are difficult to compute reliably, leading to substantial uncertainties. Here we use a recent asymptotically exact theory for the DNA extension in the "extended de Gennes regime" that allows us to compare experimental results with theory. For this purpose, we performed experiments measuring the mean DNA extension and its standard deviation while varying the channel geometry, dye intercalation ratio, and ionic strength of the buffer. The experimental results agree very well with theory at high ionic strengths, indicating that the model parameters are reliable. At low ionic strengths, the agreement is less good. We discuss possible reasons. In principle, our approach allows us to measure the Kuhn length and the effective width of a single DNA molecule and more generally of semiflexible polymers in solution.

  15. Comparison Between Theory and Experiment for Wings at Supersonic Speeds

    NASA Technical Reports Server (NTRS)

    Vincenti, Walter G

    1951-01-01

    This paper presents a critical comparison made between experimental and theoretical results for the aerodynamic characteristics of wings at supersonic flight speeds. As a preliminary, a brief, nonmathematical review is given of the basic assumptions and general findings of supersonic wing theory in two and three dimensions. Published data from two-dimensional pressure-distribution tests are then used to illustrate the effects of fluid viscosity and to assess the accuracy of linear theory as compared with the more exact theories which are available in the two-dimensional case. Finally, an account is presented of an NACA study of the over-all force characteristics of three-dimensional wings at supersonic speed. In this study, the lift, pitching moment, and drag characteristics of several families of wings of varying plan form and section were measured in the wind tunnel and compared with values predicted by the three-dimensional linear theory. The regions of agreement and disagreement between experiment and theory are noted and discussed.

  16. Particle filtration: A comparison between theory and experiment

    SciTech Connect

    Quintard, M.; Whitaker, S.

    1994-12-01

    The process of filtration of non-charged, submicron particles represents an example of transport in homogeneous and heterogeneous porous media that can be analyzed using the method of volume averaging. In this article the authors develop the local volume averaged particle transport equation for a homogeneous filter and compare the results with experimental data. The particle continuity equation is represented in terms of the first correction to the Smoluchowski equation that takes into account particle inertia effects for small Stokes numbers. This leads to a cellular efficiency that contains a minimum in the efficiency as a function of the particle size, and this allows them to identify the most penetrating particle size. Comparison of the theory with experimental results indicates that the first correction to the Smoluchowski equation gives reasonable results for the most penetrating particle size and for smaller particles; however, results for larger particles clearly indicate the need to extend the Smoluchowski equation to include higher order corrections. The influence of local heterogeneities on the measured filter efficiency may account for some of the observed differences between theory and experiment.

  17. Test Experience Effects in Longitudinal Comparisons of Adult Cognitive Functioning

    ERIC Educational Resources Information Center

    Salthouse, Timothy

    2015-01-01

    It is widely recognized that experience with cognitive tests can influence estimates of cognitive change. Prior research has estimated experience effects at the level of groups by comparing the performance of a group of participants tested for the second time with the performance of a different group of participants at the same age tested for the…

  18. Theory and Experiment of Multielement Airfoils: A Comparison

    NASA Technical Reports Server (NTRS)

    Czerwiec, Ryan; Edwards, J. R.; Rumsey, C. L.; Hassan, H. A.

    2000-01-01

    A detailed comparison of computed and measured pressure distributions, velocity profiles, transition onset, and Reynolds shear stresses for multi-element airfoils is presented. It is shown that the transitional k-zeta model, which is implemented into CFL3D, does a good job of predicting pressure distributions, transition onset, and velocity profiles with the exception of velocities in the slat wake region. Considering the fact that the hot wire used was not fine enough to resolve Reynolds stresses in the boundary layer, comparisons of turbulence stresses varied from good to fair. It is suggested that the effects of unsteadiness be thoroughly evaluated before more complicated transition/turbulence models are used. Further, it is concluded that the present work presents a viable and economical method for calculating laminar/transitional/turbuient flows over complex shapes without user interface.

  19. Comparison of two experiments on radiative neutron decay

    NASA Astrophysics Data System (ADS)

    Khafizov, R. U.; Tolokonnikov, S. V.; Solovei, V. A.; Kolhidashvili, M. R.

    2009-12-01

    Over 10 years ago we proposed an experiment on measuring the characteristics of radiative neutron decay in papers [1, 2]. At the same time we had published the theoretical spectrum of radiative gamma quanta, calculated within the framework of the electroweak interactions, on the basis of which we proposed the methodology for the future experiment [3, 4]. However, because we were denied beam time on the intensive cold neutron beam at ILL (Grenoble, France) for a number of years, we could only conduct the experiment in 2005 on the newly opened FRMII reactor of Technical University of Muenchen. The main result of this experiment was the discovery of radiative neutron decay and the measurement of its relative intensity B.R. = (3.2 ± 1.6) × 10-3 with C.L. = 99.7% for radiative gamma quanta with energy over 35 kev [5, 6]. Over a year after our first announcement about the results of the conducted experiment, “Nature” [7] published a letter asserting that its authors have also measured the branching ratio of radiative neutron decay B.R. = (3.13 ± 0.34) × 10-3 with c.l. = 68% and gamma quanta energy from 15 to 340 kev. This article aims to compare these two experiments. It is shown that the use of strong magnetic fields in the NIST (Washington, USA) experiment methodology not only prevents any exact measurement of the branching ratio and identification of radiative neutron decay events, but also makes registration of ordinary neutron decay events impossible.

  20. A national comparison of biochemistry and molecular biology capstone experiences.

    PubMed

    Aguanno, Ann; Mertz, Pamela; Martin, Debra; Bell, Ellis

    2015-01-01

    Recognizing the increasingly integrative nature of the molecular life sciences, the American Society for Biochemistry and Molecular Biology (ASBMB) recommends that Biochemistry and Molecular Biology (BMB) programs develop curricula based on concepts, content, topics, and expected student outcomes, rather than courses. To that end, ASBMB conducted a series of regional workshops to build a BMB Concept Inventory containing validated assessment tools, based on foundational and discipline-specific knowledge and essential skills, for the community to use. A culminating activity, which integrates the educational experience, is often part of undergraduate molecular life science programs. These "capstone" experiences are commonly defined as an attempt to measure student ability to synthesize and integrate acquired knowledge. However, the format, implementation, and approach to outcome assessment of these experiences are quite varied across the nation. Here we report the results of a nation-wide survey on BMB capstone experiences and discuss this in the context of published reports about capstones and the findings of the workshops driving the development of the BMB Concept Inventory. Both the survey results and the published reports reveal that, although capstone practices do vary, certain formats for the experience are used more frequently and similarities in learning objectives were identified. The use of rubrics to measure student learning is also regularly reported, but details about these assessment instruments are sparse in the literature and were not a focus of our survey. Finally, we outline commonalities in the current practice of capstones and suggest the next steps needed to elucidate best practices.

  1. A Comparison of Metamodeling Techniques via Numerical Experiments

    NASA Technical Reports Server (NTRS)

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

    2016-01-01

    This paper presents a comparative analysis of a few metamodeling techniques using numerical experiments for the single input-single output case. These experiments enable comparing the models' predictions with the phenomenon they are aiming to describe as more data is made available. These techniques include (i) prediction intervals associated with a least squares parameter estimate, (ii) Bayesian credible intervals, (iii) Gaussian process models, and (iv) interval predictor models. Aspects being compared are computational complexity, accuracy (i.e., the degree to which the resulting prediction conforms to the actual Data Generating Mechanism), reliability (i.e., the probability that new observations will fall inside the predicted interval), sensitivity to outliers, extrapolation properties, ease of use, and asymptotic behavior. The numerical experiments describe typical application scenarios that challenge the underlying assumptions supporting most metamodeling techniques.

  2. Experiments for comparison of small scale rainfall simulators

    NASA Astrophysics Data System (ADS)

    Iserloh, T.; Ries, J. B.

    2012-04-01

    Small scale portable rainfall simulators are an essential tool in research of recent process dynamics of soil erosion. Such rainfall simulators differ in design, rainfall intensities, rain spectra etc., impeding comparison of the results. Due to different research questions a standardisation of rainfall simulation is not in sight. Nevertheless, the data become progressively important for soil erosion modelling and therefore the basis for decision-makers in application-oriented erosion protection. The project aims at providing a criteria catalogue for estimation of the different simulators as well as the comparability of the results and a uniform calibration procedure for generated rainfall. Within the project "Comparability of simulation results of different rainfall simulators as input data for soil erosion modelling (Deutsche Forschungsgemeinschaft - DFG, Project No. Ri 835/6-1)" many rainfall simulators used by European research groups were compared. The artificially generated rainfall of the rainfall simulators at the Universities Basel, La Rioja, Malaga, Trier, Tübingen, Valencia, Wageningen, Zaragoza and at different Spanish CSIC-institutes (Almeria, Cordoba, Granada, Murcia, Zaragoza) were measured with the same methods (Laser Precipitation Monitor for drop spectra and rain collectors for spatial distribution). The data are very beneficial for improvements of simulators and comparison of simulators and results. Furthermore, they can be used for comparative studies with natural rainfall spectra. A broad range of rainfall data was measured (e.g. intensity: 30 - 149 mmh-1, Christiansen Coefficient for spatial rainfall distribution 61 - 98 %, mean drop diameter 0.375 - 5.0 mm, mean kinetic energy expenditure 25 - 1322 J m-2 h-1, mean kinetic energy per unit area and unit depth of rainfall 4 - 14 J m-2 mm-1). Similarities among the simulators could be found e.g. concerning drop size distributions (maximum drop numbers are reached within the two smallest drop

  3. Validation of KENO V.a Comparison with Critical Experiments

    SciTech Connect

    Jordan, W.C.

    1999-01-01

    Section 1 of this report documents the validation of KENO V.a against 258 critical experiments. Experiments considered were primarily high or low enriched uranium systems. The results indicate that the KENO V.a Monte Carlo Criticality Program accurately calculates a broad range of critical experiments. A substantial number of the calculations showed a positive or negative bias in excess of 1 1/2% in k-effective (k{sub eff}). Classes of criticals which show a bias include 3% enriched green blocks, highly enriched uranyl fluoride slab arrays, and highly enriched uranyl nitrate arrays. If these biases are properly taken into account, the KENO V.a code can be used with confidence for the design and criticality safety analysis of uranium-containing systems. Section 2 of this report documents the results of investigation into the cause of the bias observed in Sect. 1. The results of this study indicate that the bias seen in Sect. 1 is caused by code bias, cross-section bias, reporting bias, and modeling bias. There is evidence that many of the experiments used in this validation and in previous validations are not adequately documented. The uncertainty in the experimental parameters overshadows bias caused by the code and cross sections and prohibits code validation to better than about 1% in k{sub eff}.

  4. Reactive flow calibration for diaminoazoxyfurazan (DAAF) and comparison with experiment

    NASA Astrophysics Data System (ADS)

    Johnson, Carl; Francois, Elizabeth Green; Morris, John

    2012-03-01

    Diaminoazoxyfurazan (DAAF) has a number of desirable properties; it is sensitive to shock while being insensitive to initiation by low level impact or friction, it has a small failure diameter, and its manufacturing process is inexpensive with minimal environmental impact. In light of its unique properties, DAAF based materials have gained interest for possible applications in insensitive munitions. In order to facilitate hydrocode modeling of DAAF and DAAF based formulations, we have developed a set of reactive flow parameters which were calibrated using published experimental data as well as recent experiments at LANL. Hydrocode calculations using the DAAF reactive flow parameters developed in the course of this work were compared to rate stick experiments, small scale gap tests, as well as the Onionskin experiment. Hydrocode calculations were compared directly to streak image results using numerous tracer points in conjunction with an external algorithm to match the data sets. The calculations display a reasonable agreement with experiment with the exception of effects related to shock desensitization of explosive.

  5. Inverse boundary-layer theory and comparison with experiment

    NASA Technical Reports Server (NTRS)

    Carter, J. E.

    1978-01-01

    Inverse boundary layer computational procedures, which permit nonsingular solutions at separation and reattachment, are presented. In the first technique, which is for incompressible flow, the displacement thickness is prescribed; in the second technique, for compressible flow, a perturbation mass flow is the prescribed condition. The pressure is deduced implicitly along with the solution in each of these techniques. Laminar and turbulent computations, which are typical of separated flow, are presented and comparisons are made with experimental data. In both inverse procedures, finite difference techniques are used along with Newton iteration. The resulting procedure is no more complicated than conventional boundary layer computations. These separated boundary layer techniques appear to be well suited for complete viscous-inviscid interaction computations.

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

    SciTech Connect

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

    2014-03-15

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

  7. MISSE Thermal Control Materials with Comparison to Previous Flight Experiments

    NASA Technical Reports Server (NTRS)

    Finckenor, Miria; Pippin, H. Gary; Frey, George

    2008-01-01

    Many different passive thermal control materials were flown as part of the Materials on International Space Station Experiment (MISSE), including inorganic coatings, anodized aluminum, and multi-layer insulation materials. These and other material samples were exposed to the low Earth orbital environment of atomic oxygen, ultraviolet radiation, thermal cycling, and hard vacuum, though atomic oxygen exposure was limited for some samples. Materials flown on MISSE-1 and MISSE-2 were exposed to the space environment for nearly four years. Materials flown on MISSE-3, MISSE-4, and MISSE-5 were exposed to the space environment for one year. Solar absorptance, infrared emittance, and mass measurements indicate the durability of these materials to withstand the space environment. Effects of short duration versus long duration exposure on ISS are explored, as well as comparable data from previous flight experiments, such as the Passive Optical Sample Assembly (POSA), Optical Properties Monitor (OPM), and Long Duration Exposure Facility (LDEF).

  8. Male and Female Superintendents: A Comparison of Differences in Salaries, Interview Experiences, and Contract Negotiations

    ERIC Educational Resources Information Center

    Long, Alan

    2010-01-01

    This study reports the results of a comparison of differences in salary, interview experiences, and contract negotiations for male and female superintendents. Other variables of interest include educational attainment and educational experiences. The study participants (N = 161) consisted of practicing superintendents from four regions of the…

  9. An Enzymatic Clinical Chemistry Laboratory Experiment Incorporating an Introduction to Mathematical Method Comparison Techniques

    ERIC Educational Resources Information Center

    Duxbury, Mark

    2004-01-01

    An enzymatic laboratory experiment based on the analysis of serum is described that is suitable for students of clinical chemistry. The experiment incorporates an introduction to mathematical method-comparison techniques in which three different clinical glucose analysis methods are compared using linear regression and Bland-Altman difference…

  10. School Climate and the Experience of LGBT Students: A Comparison of the United States and Israel

    ERIC Educational Resources Information Center

    Pizmony-Levy, Oren; Kosciw, Joseph G.

    2016-01-01

    This article examines the school experience of lesbian, gay, bisexual, and transgender (LGBT) students in the United States and Israel. Through comparison of the sociocultural and edu-cational contexts, the authors assess whether school experience of LGBT students differs or operates similarly across countries. The authors use data from the…

  11. Comparison of approaches for predicting solute transport: sandbox experiments.

    PubMed

    Illman, Walter A; Berg, Steven J; Yeh, Tian-Chyi Jim

    2012-01-01

    The main purpose of this paper was to compare three approaches for predicting solute transport. The approaches include: (1) an effective parameter/macrodispersion approach (Gelhar and Axness 1983); (2) a heterogeneous approach using ordinary kriging based on core samples; and (3) a heterogeneous approach based on hydraulic tomography. We conducted our comparison in a heterogeneous sandbox aquifer. The aquifer was first characterized by taking 48 core samples to obtain local-scale hydraulic conductivity (K). The spatial statistics of these K values were then used to calculate the effective parameters. These K values and their statistics were also used for kriging to obtain a heterogeneous K field. In parallel, we performed a hydraulic tomography survey using hydraulic tests conducted in a dipole fashion with the drawdown data analyzed using the sequential successive linear estimator code (Yeh and Liu 2000) to obtain a K distribution (or K tomogram). The effective parameters and the heterogeneous K fields from kriging and hydraulic tomography were used in forward simulations of a dipole conservative tracer test. The simulated and observed breakthrough curves and their temporal moments were compared. Results show an improvement in predictions of drawdown behavior and tracer transport when the K tomogram from hydraulic tomography was used. This suggests that the high-resolution prediction of solute transport is possible without collecting a large number of small-scale samples to estimate flow and transport properties that are costly to obtain at the field scale.

  12. Comparisons of Single Drop Impact Simulations with Experiments

    NASA Astrophysics Data System (ADS)

    Medam, Krishna Teja

    As the size of electronic equipment is reduced, the ability to reject waste heat is also reduced due to smaller component surface areas, thereby affecting the component performance and finally leading to the damage of the component. Spray cooling offers a means to achieve high rates of heat transfer from microelectronic components and other high energy density devices. As a first step in investigating spray cooling, a single liquid drop impacting onto a thin liquid film was studied at isothermal conditions. 2D axisymmetric cases were simulated with ANSYS Fluent and 3D cases with OpenFOAM using the Volume of Fluid (VOF) model. The post processing of the results was performed in Surfer (Version 9) software in order to determine the liquid film thickness and then calculate the volume of the liquid under the cavity (sub-cavity liquid volume) as functions of time. These simulations agreed with the experimental data during the cavity formation phase, but did not closely match with the experiments during the refilling of the cavity in the majority of the cases. It was speculated that the discrepancies could be due to the three dimensional instabilities leading to droplet ejection from the crown during the retraction phase. These instabilities are omitted from the 2D simulations, and were not adequately resolved in the 3D simulations. For this reason, identical cases were simulated in 3D in OpenFOAM using the VOF model. The improved agreement with experiments obtained with the three dimensional simulations is discussed.

  13. Comparison of intersecting pedestrian flows based on experiments

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Seyfried, A.

    2014-07-01

    Intersections of pedestrian flows feature multiple types, varying in the numbers of flow directions as well as intersecting angles. In this article results from intersecting flow experiments with two different intersecting angles are compared. To analyze the transport capabilities the Voronoi method is used to resolve the fine structure of the resulting velocity-density relations and spatial dependence of the measurements. The fundamental diagrams of various flow types are compared and show no apparent difference with respect to the intersecting angle 90° and 180°. This result indicates that head-on conflicts of different types of flow have the same influence on the transport properties of the system, which demonstrates the high self-organization capabilities of pedestrians.

  14. Comparison of calculated and experimental results of fragmenting cylinder experiments

    SciTech Connect

    WILSON,L.T.; REEDAL,D.R.; KIPP,MARLIN E.; MARTINEZ,REINA R.; GRADY,D.E.

    2000-06-02

    The Grady-Kipp fragmentation model provides a physically based method for determining the fracture and breakup of materials under high loading rates. Recently, this model has been implemented into the CTH Shock Physics Code and has been used to simulate several published experiments. Materials studied in this paper are AerMet 100 steel and a 90% tungsten alloy. The experimental geometry consists of a right circular cylinder filled with an explosive main charge that is initiated at its center. The sudden expansion of the resulting detonation products causes fracture of the cylinder. Strain rates seen in the cylinder are on the order of 10{sup 4} s{sup {minus}1}. The average fragment sizes calculated with the Grady-Kipp fragmentation model successfully replicate the mean fragment size obtained from the experimental fragment distribution. When Poisson statistics are applied to the calculated local average fragment sizes, good correlation is also observed with the shape of the experimental cumulative fragment distribution. The experimental fragmentation results, CTH numerical simulations, and correlation of these numerical results with the experimental data are described.

  15. Pig Organ Energy Loss Comparison Experiments Using BBs.

    PubMed

    Maiden, Nicholas R; Musgrave, Ian; Fisk, Wesley; Byard, Roger W

    2016-05-01

    Torso models for ballistics research require that the mechanical properties of simulant materials must match the heterogeneous nature of tissues/organs within the human thorax/abdomen. A series of energy loss experiments were conducted on fresh porcine organs/tissues at room temperature and 37°C, using steel 4.5 mm BBs fired from a Daisy(®) brand air rifle. They were compared to FBI and NATO specification ordnance gelatin and a candidate surrogate material called Simulant "A". Two CED M2 chronographs measured BB velocity. The resulting energy loss was established using KE = 1/2 mv² before and after target perforation. The combined results at room temperature and 37°C were as follows: FBI specification gelatin was similar (p > 0.05) to heart and lung, spleen was similar to NATO specification gelatin, Simulant "A" was similar to hindquarter muscle, and hindquarter muscle, kidney, and spleen were similar to each other regarding energy retardation. These results can be used as a basis for the development of simulant materials to create an anatomically correct heterogeneous model. PMID:27122406

  16. Comparison of electron cloud simulation and experiments in the high-current experiment

    SciTech Connect

    Cohen, R.H.; Friedman, A.; Covo, M. Kireeff; Lund, S.M.; Molvik, A.W.; Bieniosek, F.M.; Seidl, P.A.; Vay, J.-L.; Verboncoeur, J.; Stoltz, P.; Veitzer, S.

    2004-08-27

    A set of experiments has been performed on the High-Current Experiment (HCX) facility at LBNL, in which the ion beam is allowed to collide with an end plate and thereby induce a copious supply of desorbed electrons. Through the use of combinations of biased and grounded electrodes positioned in between and downstream of the quadrupole magnets, the flow of electrons upstream into the magnets can be turned on or off. Properties of the resultant ion beam are measured under each condition. The experiment is modeled via a full three-dimensional, two species (electron and ion) particle simulation, as well as via reduced simulations (ions with appropriately chosen model electron cloud distributions, and a high-resolution simulation of the region adjacent to the end plate). The three-dimensional simulations are the first of their kind and the first to make use of a timestep-acceleration scheme that allows the electrons to be advanced with a timestep that is not small compared to the highest electron cyclotron period. The simulations reproduce qualitative aspects of the experiments, illustrate some unanticipated physical effects, and serve as an important demonstration of a developing simulation capability.

  17. Comparison of Electron Cloud Simulation and Experiments in the High-Current Experiment

    SciTech Connect

    Cohen, R; Friedman, A; Covo, M K; Lund, S; Molvik, A; Bieniosek, F; Seidl, P; Vay, J; Verboncoeur, J; Stoltz, P; Veitzer, S

    2004-10-07

    A set of experiments has been performed on the High-Current Experiment (HCX) facility at LBNL, in which the ion beam is allowed to collide with an end plate and thereby induce a copious supply of desorbed electrons. Through the use of combinations of biased and grounded electrodes positioned in between and downstream of the quadrupole magnets, the flow of electrons upstream into the magnets can be turned on or off. Properties of the resultant ion beam are measured under each condition. The experiment is modeled via a full three-dimensional, two species (electron and ion) particle simulation, as well as via reduced simulations (ions with appropriately chosen model electron cloud distributions, and a high-resolution simulation of the region adjacent to the end plate). The three-dimensional simulations are the first of their kind and the first to make use of a timestep-acceleration scheme that allows the electrons to be advanced with a timestep that is not small compared to the highest electron cyclotron period. The simulations reproduce qualitative aspects of the experiments, illustrate some unanticipated physical effects, and serve as an important demonstration of a developing simulation capability.

  18. The roles of praise and social comparison information in the experience of pride.

    PubMed

    Webster, J Matthew; Duvall, Jamieson; Gaines, Leslie M; Smith, Richard H

    2003-04-01

    The authors examined the roles of social comparisons, publicity of success, and praise on the experience of pride in an experiment in which college students successfully completed a timed intelligence task in private and later received 1 of 4 types of feedback from the experimenter: no feedback (private), mere public acknowledgment of completion, general praise containing both a public and an evaluative component, or praise containing explicit comparison information. Half of the participants also received written normative information suggesting they performed at a high level. Participants then completed a number of dependent measures, including a key measure of pride. Overall, results suggest that the public aspect of a performance, together with the superior standing suggested by any praise accompanying this publicity, is important in the experience of pride.

  19. The roles of praise and social comparison information in the experience of pride.

    PubMed

    Webster, J Matthew; Duvall, Jamieson; Gaines, Leslie M; Smith, Richard H

    2003-04-01

    The authors examined the roles of social comparisons, publicity of success, and praise on the experience of pride in an experiment in which college students successfully completed a timed intelligence task in private and later received 1 of 4 types of feedback from the experimenter: no feedback (private), mere public acknowledgment of completion, general praise containing both a public and an evaluative component, or praise containing explicit comparison information. Half of the participants also received written normative information suggesting they performed at a high level. Participants then completed a number of dependent measures, including a key measure of pride. Overall, results suggest that the public aspect of a performance, together with the superior standing suggested by any praise accompanying this publicity, is important in the experience of pride. PMID:12735519

  20. Transonic pressure measurements and comparison of theory to experiment for three arrow-wing configurations

    NASA Technical Reports Server (NTRS)

    Manro, M. E.

    1982-01-01

    Wind tunnel tests of arrow-wing body configurations consisting of flat, twisted, and cambered twisted wings, as well as a variety of leading and trailing edge control surface deflections, were conducted at Mach numbers from 0.4 to 1.05 to provide an experimental pressure data base for comparison with theoretical methods. Theory to experiment comparisons of detailed pressure distributions were made using state of the art attached flow methods. Conditions under which these theories are valid for these wings are presented.

  1. Supersonic pressure measurements and comparison of theory to experiment for an arrow-wing configuration

    NASA Technical Reports Server (NTRS)

    Manro, M. E.

    1976-01-01

    A wind tunnel test of an arrow-wing-body configuration consisting of flat and twisted wings, as well as leading- and trailing-edge control surface deflections, was conducted at Mach numbers from 1.54 to 2.50 to provide an experimental pressure data base for comparison with theoretical methods. Theory-to-experiment comparisons of detailed pressure distributions were made using a state-of-the-art inviscid flow, constant-pressure-panel method. Emphasis was on conditions under which this theory is valid for both flat and twisted wings.

  2. Comparison of Electron Cloud Simulation and Experiments in the High-Current Experiment

    SciTech Connect

    Cohen, R H; Friedman, A; Covo, M K; Lund, S M; Molvik, A W; Bieniosek, F M; Seidl, P A; Vay, J; Stoltz, P; Veitzer, S

    2004-11-11

    Contaminating clouds of electrons are a common concern for accelerators of positive-charged particles, but there are some unique aspects of heavy-ion accelerators for fusion and high-energy density physics which make modeling such clouds especially challenging. In particular, self-consistent electron and ion simulation is required, including a particle advance scheme which can follow electrons in regions where electrons are strongly, weakly, and un-magnetized. We describe our approach to such self-consistency, and in particular a scheme for interpolating between full-orbit (Boris) and drift-kinetic particle pushes that enables electron time steps long compared to the typical gyro period in the magnets. We present tests and applications: simulation of electron clouds produced by three different kinds of sources indicates the sensitivity of the cloud shape to the nature of the source; first-of-a-kind self-consistent simulation of electron-cloud experiments on the High-Current Experiment (HCX) at LBNL, in which the machine can be flooded with electrons released by impact of the ion beam on an end plate, demonstrate the ability to reproduce key features of the ion-beam phase space; and simulation of a two-stream instability of thin beams in a magnetic field demonstrate the ability of the large-timestep mover to accurately calculate the instability.

  3. Microwave Transmission Through the Electron Cloud at the Fermilab Main Injector: Simulation and Comparison with Experiment

    SciTech Connect

    Lebrun, Paul L.G.; Veitzer, Seth Andrew; /Tech-X, Boulder

    2009-04-01

    Simulations of the microwave transmission properties through the electron cloud at the Fermilab Main Injector have been implemented using the plasma simulation code 'VORPAL'. Phase shifts and attenuation curves have been calculated for the lowest frequency TE mode, slightly above the cutoff frequency, in field free regions, in the dipoles and quadrupoles. Preliminary comparisons with experimental results for the dipole case are showed and will guide the next generation of experiments.

  4. Comparison of Computational Results with a Low-g, Nitrogen Slosh and Boiling Experiment

    NASA Technical Reports Server (NTRS)

    Stewart, Mark; Moder, Jeff

    2015-01-01

    The proposed paper will compare a fluid/thermal simulation, in FLUENT, with a low-g, nitrogen slosh experiment. The French Space Agency, CNES, performed cryogenic nitrogen experiments in several zero gravity aircraft campaigns. The computational results have been compared with high-speed photographic data, pressure data, and temperature data from sensors on the axis of the cylindrically shaped tank. The comparison between these experimental and computational results is generally favorable: the initial temperature stratification is in good agreement, and the two-phase fluid motion is qualitatively captured.

  5. Preliminary comparison of theory and experiment for a conical, pressurized-fluidized-bed coal combustor

    NASA Technical Reports Server (NTRS)

    Patch, R. W.

    1979-01-01

    A published model was used for a comparison of theory with an actual combustor burning caking bituminous coal and using limestone to reduce sulfur dioxide emission. Theoretical bed pressure drop was in good agreement with experiment. The burnable carbon elutriated was not in agreement with experiment, at least partly because the exhaust port was apparently below the transport disengaging height. The observed nitrogen oxides emission rate was about half the theoretical value. There was order-or-magnitude agreement of sulfur dioxide emission rates.

  6. Comparisons of theoretically predicted transport from ion temperature gradient instabilities to L-mode tokamak experiments

    SciTech Connect

    Kotschenreuther, M.; Wong, H.V.; Lyster, P.L.; Berk, H.L.; Denton, R.; Miner, W.H.; Valanju, P.

    1991-12-01

    The theoretical transport from kinetic micro-instabilities driven by ion temperature gradients is a sheared slab is compared to experimentally inferred transport in L-mode tokamaks. Low noise gyrokinetic simulation techniques are used to obtain the ion thermal transport coefficient X. This X is much smaller than in experiments, and so cannot explain L-mode confinement. Previous predictions based on fluid models gave much greater X than experiments. Linear and nonlinear comparisons with the fluid model show that it greatly overestimates transport for experimental parameters. In addition, disagreements among previous analytic and simulation calculations of X in the fluid model are reconciled.

  7. Unwanted sexual contact on campus: a comparison of women's and men's experiences.

    PubMed

    Banyard, Victoria L; Ward, S; Cohn, E S; Plante, E G; Moorhead, C; Walsh, W

    2007-01-01

    While sexual victimization continues to be a problem on college campuses, recent attention has been drawn to understanding gender differences in victimization rates and consequences. To date, these studies remain relatively few in number. The current study surveyed 651 male and female undergraduate students about unwanted sexual experiences during 1 academic year. Comparison of men and women revealed expected differences in incidence rates, with women reporting higher rates of unwanted contact. Within the subsample of reported victims, however, there was gender similarity in terms of the context of unwanted sexual experiences. Analyses also revealed the negative consequences of these experiences for both men and women and low rates of disclosure regardless of gender. Across the full sample of students surveyed, there were interesting gender differences in knowledge of campus support services, with women more likely to have attended a prevention program and to have indicated greater knowledge of rape crisis services. PMID:17390563

  8. L-Band Microwave Experiment On Russian Investigational Satellite, First Results And Comparison With SMOS Data

    NASA Astrophysics Data System (ADS)

    Smirnov, M.; Khaldin, A.

    2013-12-01

    The main scientific objective of mission with Zond-PP on Russian investigational satellite MKA-FKI No1 is development of techniques for retrieval: sea salinity in open oceans, soil moisture in global scales, vegetation state characteristics, sea ice characteristics. At the beginning stage of space experiments the main goals were to develop and test new space microwave radiometric instrument in order to solve technical objectives: investigation of RFI in L-band all over the globe, development and testing in-flight calibration techniques and others. First obtained results of our observations are presented. Zond-PP results were compared with MIRAS. For comparison were used results of brightness temperatures measurements obtained from Zond-PP and MIRAS in the same regions with minimal time difference. Results of comparison show general accordance in the brightness temperatures levels.

  9. Comparison between theory and experiment for universal thermodynamics of a homogeneous, strongly correlated Fermi gas

    SciTech Connect

    Hu Hui; Liu Xiaji; Drummond, Peter D.

    2011-06-15

    We compare the theoretical predictions for universal thermodynamics of a homogeneous, strongly correlated Fermi gas with the latest experimental measurements reported by the ENS group [S. Nascimbene et al., Nature (London) 463, 1057 (2010)] and the Tokyo group [M. Horikoshi et al., Science 327, 442 (2010)]. The theoretical results are obtained using two diagrammatic theories, together with a virial expansion theory combined with a Pade approximation. We find good agreement between theory and experiment. In particular, the virial expansion, using a Pade approximation up to third order, describes the experimental results extremely well down to the superfluid transition temperature, T{sub c{approx}}0.16T{sub F}, where T{sub F} is the Fermi temperature. The comparison in this work complements our previous comparative study on the universal thermodynamics of a strongly correlated but trapped Fermi gas. The comparison also raises interesting issues about the unitary entropy and the applicability of the Pade approximation.

  10. Chinese students' science-related experiences: Comparison of the ROSE study in Xinjiang and Shanghai

    NASA Astrophysics Data System (ADS)

    Yeung, Yau-yuen; Li, Yufeng

    2015-05-01

    Background: Students' daily-life experiences may render favorable effects on the students' affective domain like interest, enthusiasm, motivation, joy, curiosity, awareness, and eagerness to learn science as not commonly found in the classroom environment. However, no rigorous research has been reported on those aspects in Mainland China despite many recent studies done in various Western countries. Purpose: This paper aims to report and compare the science-related experiences of ninth-graders from two places (in Urumqi City of Xinjiang province and Shanghai) in China through a large-scale survey of their junior secondary three students. Sample: The sample consists of 4115 students in Urumqi City (from 28 schools) and Shanghai (from 25 schools). Design and methods: This study adopted a Likert scale questionnaire instrument, as translated from the international Relevance Of Science Education (ROSE) Project. From a confirmatory factor analysis of the data, we identify and focus on six factors which are directly correlated with students' science-related experiences outside school environment in Xinjiang and Shanghai and employ relevant factor scores to compare the gender, regional, and socioeconomic effects. Results: As revealed by the t-test, gender and regional differences were statistically significant in affecting (1) students' outdoor living experience, (2) hands-on experience of transportation, and (3) their daily-life experience with do-it-yourself tools and models. In all three aspects, boys and Xinjiang students possessed richer experiences than girls and Shanghai students, respectively. Conclusions: Based on ANOVA tests, Shanghai students' out-of-school science-related experiences were more often significantly affected by various socioeconomic variables (including their parents' education and occupation and their family income) than Xinjiang students. From cross-regional comparison, Chinese students had much fewer science-related experiences than those of

  11. Comparison of Fire Model Predictions with Experiments Conducted in a Hangar With a 15 Meter Ceiling

    NASA Technical Reports Server (NTRS)

    Davis, W. D.; Notarianni, K. A.; McGrattan, K. B.

    1996-01-01

    The purpose of this study is to examine the predictive capabilities of fire models using the results of a series of fire experiments conducted in an aircraft hangar with a ceiling height of about 15 m. This study is designed to investigate model applicability at a ceiling height where only a limited amount of experimental data is available. This analysis deals primarily with temperature comparisons as a function of distance from the fire center and depth beneath the ceiling. Only limited velocity measurements in the ceiling jet were available but these are also compared with those models with a velocity predictive capability.

  12. RELAP5 assessment: LOFT large break L2-5

    SciTech Connect

    Thompson, S L; Kmetyk, L N

    1984-02-01

    RELAP5 is part of an effort to determine the ability of various systems codes to predict the detailed thermal/hydraulic response of LWRs during accident and off-normal conditions. The RELAP5 code is being assessed at SNLA against test data from various integral and separate effects test facilities. As part of this assessment matrix, a large break transient performed at the LOFT facility has been analyzed. The results show that RELAP5/MOD1 correctly calculates many of the major system variables (i.e., pressure, break flows, peak clad temperature) early in a large break LOCA. The major problems encountered in the analyses were incorrect pump coastdown and loop seal clearing early in the calculation, excessive pump speedup later in the transient (probably due to too much condensation-induced pressure drop at the ECC injection point), and excess ECC bypass calculated throughout the later portions of the test; only the latter problem significantly affected the overall results. This excess ECC bypass through the downcomer and vessel-side break resulted in too-large late-time break flows and high system pressure due to prolonged choked flow conditions. It also resulted in a second core heatup being calculated after the accumulator emptied, since water was not being retained in the vessel. Analogous calculations with a split-downcomer nodalization delivered some ECC water to the lower plenum, which was then swept up the core and upper plenum and out the other (pump-side) break; thus no significant differences in long-term overall behavior were evident between the calculations.

  13. Comparison between initial Magnetized Liner Inertial Fusion experiments and integrated simulations

    NASA Astrophysics Data System (ADS)

    Sefkow, A. B.; Gomez, M. R.; Geissel, M.; Hahn, K. D.; Hansen, S. B.; Harding, E. C.; Peterson, K. J.; Slutz, S. A.; Koning, J. M.; Marinak, M. M.

    2014-10-01

    The Magnetized Liner Inertial Fusion (MagLIF) approach to ICF has obtained thermonuclear fusion yields using the Z facility. Integrated magnetohydrodynamic simulations provided the design for the first neutron-producing experiments using capabilities that presently exist, and the initial experiments measured stagnation radii rstag < 75 μm, temperatures around 3 keV, and isotropic neutron yields up to YnDD = 2 ×1012 from imploded liners reaching peak velocities around 70 km/s over an implosion time of about 60 ns. We present comparisons between the experimental observables and post-shot degraded integrated simulations. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  14. Cooperative dynamics in polymer melts: a comparison of theoretical predictions with Neutron Spin Echo experiments

    NASA Astrophysics Data System (ADS)

    Guenza, Marina

    2009-03-01

    We present a comparison between theoretical predictions of the Generalized Langevin Equation for Cooperative Dynamics (CDGLE) and Neutron Spin Echo data of dynamics structure factors for polyethylene melts. Experiments, peformed by Zamponi end coowrkers, cover an extended range of length- and time-scales providing a compelling test for the theoretical approach. Samples investigated include chains with increasing molecular weights, undergoing dynamics across the unentangled to entangled transition. Measured center-of- mass mean-square displacements display a crossover from subdiffusive to diffusive dynamics. The Generalized Langevin Equation for Cooperative Dynamics relates this anomalous diffusion to the presence of the interpolymer potential, which correlates the dynamics of a group of slowly diffusing molecules in a dynamically heterogeneous liquid. Theoretical predictions of the subdiffusive behavior, its crossover to free diffusion, and of the number of macromolecules undergoing cooperative motion are in quantitative agreement with experiments.

  15. Comparison of Stratospheric Aerosol and Gas Experiment II and balloon-borne stratospheric water vapor measurements

    NASA Technical Reports Server (NTRS)

    Pruvost, P.; Ovarlez, J.; Lenoble, J.; Chu, W. P.

    1993-01-01

    The Stratospheric Aerosol and Gas Experiment II has one channel at 940 nm related to water vapor. Two inversion procedures were developed independently in order to obtain the water vapor profile: the Chahine method by the Langley Research Center, and the Mill method by the Laboratoire d'Optique Atmospherique. Comparisons were made between these two algorithms and some results are presented at midlatitudes (about 45 deg N) and tropical latitudes (12-25 deg S). They are compared with in situ frost point hygrometer data provided by balloon experiments from the Laboratoire de Meteorologie Dynamique. At +/- 0.5 ppmv, agreement between the inversion results and the experimental results was obtained in the altitude range from 18-19 to 26-27 km. Below 18-19 km and above 26-27 km the error is larger (sometimes 1 ppmv and more).

  16. A nonparametric approach for statistical comparison of results from alternative forced choice experiments

    NASA Astrophysics Data System (ADS)

    Noo, Frédéric; Wunderlich, Adam; Heuscher, Dominic; Schmitt, Katharina; Yu, Zhicong

    2013-03-01

    Task-based image quality assessment is a valuable methodology for development, optimization and evaluation of new image formation processes in x-ray computed tomography (CT), as well as in other imaging modalities. A simple way to perform such an assessment is through the use of two (or more) alternative forced choice (AFC) experiments. In this paper, we are interested in drawing statistical inference from outcomes of multiple AFC experiments that are obtained using multiple readers as well as multiple cases. We present a non-parametric covariance estimator for this problem. Then, we illustrate its usefulness with a practical example involving x-ray CT simulations. The task for this example is classification between presence or absence of one lesion with unknown location within a given object. This task is used for comparison of three standard image reconstruction algorithms in x-ray CT using four human observers.

  17. Effects of numerical methods on comparisons between experiments and simulations of shock-accelerated mixing.

    SciTech Connect

    Rider, William; Kamm, J. R.; Tomkins, C. D.; Zoldi, C. A.; Prestridge, K. P.; Marr-Lyon, M.; Rightley, P. M.; Benjamin, R. F.

    2002-01-01

    We consider the detailed structures of mixing flows for Richtmyer-Meshkov experiments of Prestridge et al. [PRE 00] and Tomkins et al. [TOM 01] and examine the most recent measurements from the experimental apparatus. Numerical simulations of these experiments are performed with three different versions of high resolution finite volume Godunov methods. We compare experimental data with simulations for configurations of one and two diffuse cylinders of SF{sub 6} in air using integral measures as well as fractal analysis and continuous wavelet transforms. The details of the initial conditions have a significant effect on the computed results, especially in the case of the double cylinder. Additionally, these comparisons reveal sensitive dependence of the computed solution on the numerical method.

  18. Visualizing the Impact of Art: An Update and Comparison of Current Psychological Models of Art Experience

    PubMed Central

    Pelowski, Matthew; Markey, Patrick S.; Lauring, Jon O.; Leder, Helmut

    2016-01-01

    The last decade has witnessed a renaissance of empirical and psychological approaches to art study, especially regarding cognitive models of art processing experience. This new emphasis on modeling has often become the basis for our theoretical understanding of human interaction with art. Models also often define areas of focus and hypotheses for new empirical research, and are increasingly important for connecting psychological theory to discussions of the brain. However, models are often made by different researchers, with quite different emphases or visual styles. Inputs and psychological outcomes may be differently considered, or can be under-reported with regards to key functional components. Thus, we may lose the major theoretical improvements and ability for comparison that can be had with models. To begin addressing this, this paper presents a theoretical assessment, comparison, and new articulation of a selection of key contemporary cognitive or information-processing-based approaches detailing the mechanisms underlying the viewing of art. We review six major models in contemporary psychological aesthetics. We in turn present redesigns of these models using a unified visual form, in some cases making additions or creating new models where none had previously existed. We also frame these approaches in respect to their targeted outputs (e.g., emotion, appraisal, physiological reaction) and their strengths within a more general framework of early, intermediate, and later processing stages. This is used as a basis for general comparison and discussion of implications and future directions for modeling, and for theoretically understanding our engagement with visual art. PMID:27199697

  19. Catchment Prediction In Changing Environments (CAPICHE): A Model Inter-Comparison Experiment

    NASA Astrophysics Data System (ADS)

    Hutton, Christopher; Nijzink, Remko; Pechlivanidis, Ilias; Capell, René; Wagener, Thorsten; Freer, Jim; Han, Dawei; Hrachowitz, Markus; Arheimer, Berit

    2016-04-01

    forcing, hydrological response and model parameter metrics (e.g. posterior distribution, parameter interactions). As part of the EUFP7 funded project Switch-On, the method is first applied in a collaborative model inter-comparison using open data from paired headwater catchments to analyse how different models simulate the effect of deforestation and subsequent re-growth on hydrological response. The simulation of paired catchments allows us to differentiate the effect of climate forcing and land-cover change on model parameters. In order to make the experiment open, the analysis code will be made available for re-use and therefore subsequent model inter-comparison.

  20. A study of dc discharge in cylindrical magnetron - comparison of experiment and PIC model

    NASA Astrophysics Data System (ADS)

    Behnke, J. F.; Csambal, C.; Tichy, M.; Kudrna, P.; Rusz, J.

    2000-10-01

    We present experimental and numerical study of the DC discharge in cylindrical magnetron in argon. The grounded discharge chamber-anode has 110 mm in length and 60 mm inner diameter. The co-axially placed cathode has 10 mm in diameter. The magnetic field is created by couple of coils. Experimental results have been obtained by radially movable planar Langmuir probe with its plane perpendicular to the magnetic field lines. The radial profiles of the floating and plasma potential, plasma density, and the electron energy distribution function have been measured. Numerical results were obtained using the modified 1D PIC code (Berkeley). The comparison between experiment and model results computed at similar conditions shows reasonable agreement in plasma density and electron mean energy. The computed electric field is usually higher than the experimental one. This difference we explain by the end effects that are not taken into account in 1D model.

  1. Coherent structures in a turbulent mixing layer - A comparison between direct numerical simulations and experiments

    NASA Technical Reports Server (NTRS)

    Metcalfe, R. W.; Menon, S.; Hussain, A. K. M. F.

    1985-01-01

    An eduction scheme has been developed in an attempt to determine the characteristics of large-scale vortical structures in a turbulent mixing layer. This analysis scheme has been applied to a set of experimental data taken in a new, larger mixing layer facility designed to minimize boundary and resonance effects. A similar scheme has been developed to apply to the results of a direct numerical simulation of a temporally growing mixing layer. A comparison of the two approaches shows important similarities in the coherent structures. The numerical simulations indicate that low levels of coherent forcing can dramatically change the evolution of the mixing layer. In the absence of such forcing, the numerical simulations and experiments show a lack of regularity in the transverse position, spacing, amplitude, shape and spanwise coherence of the large-scale vortical structures.

  2. Comparison between the atmospheric boundary layer in Paris and its rural suburbs during the ECLAP experiment

    NASA Astrophysics Data System (ADS)

    Dupont, E.; Menut, L.; Carissimo, B.; Pelon, J.; Flamant, P.

    The ECLAP experiment has been performed during the winter of 1995 in order to study the influence of the urban area of Paris on the vertical structure and diurnal evolution of the atmospheric boundary layer, in situations favourable to intense urban heat island and pollution increase. One urban site and one rural site have been instrumented with sodars, lidars and surface measurements. Additional radiosondes, 100 m masts and Eiffel Tower data were also collected. This paper gives a general overview of this experiment, and presents results of the analysis of four selected days, characterized by various wind directions and temperature inversion strengths. This analysis, which consists in a comparison between data obtained in the two sites, has been focused on three parameters of importance to the ABL dynamics: the standard deviation of vertical velocity, the surface sensible heat flux, and the boundary layer height. The vertical component of turbulence is shown to be enhanced by the urban area, the amplitude of this effect strongly depending on the meteorological situation. The sensible heat flux in Paris is generally found larger than in the rural suburbs. The most frequent differences range from 25-65 W m -2, corresponding to relative differences of 20-60%. The difference of unstable boundary layer height between both sites are most of the time less than 100 m. However, sodar and temperature data show that the urban influence is enhanced during night-time and transitions between stable and unstable regimes.

  3. Numerical investigation of two interacting parallel thruster-plumes and comparison to experiment

    NASA Astrophysics Data System (ADS)

    Grabe, Martin; Holz, André; Ziegenhagen, Stefan; Hannemann, Klaus

    2014-12-01

    Clusters of orbital thrusters are an attractive option to achieve graduated thrust levels and increased redundancy with available hardware, but the heavily under-expanded plumes of chemical attitude control thrusters placed in close proximity will interact, leading to a local amplification of downstream fluxes and of back-flow onto the spacecraft. The interaction of two similar, parallel, axi-symmetric cold-gas model thrusters has recently been studied in the DLR High-Vacuum Plume Test Facility STG under space-like vacuum conditions, employing a Patterson-type impact pressure probe with slot orifice. We reproduce a selection of these experiments numerically, and emphasise that a comparison of numerical results to the measured data is not straight-forward. The signal of the probe used in the experiments must be interpreted according to the degree of rarefaction and local flow Mach number, and both vary dramatically thoughout the flow-field. We present a procedure to reconstruct the probe signal by post-processing the numerically obtained flow-field data and show that agreement to the experimental results is then improved. Features of the investigated cold-gas thruster plume interaction are discussed on the basis of the numerical results.

  4. Comparison of chemical and nuclear explosions: Numerical simulations of the Non-Proliferation Experiment

    SciTech Connect

    Kamm, J.R.; Bos, R.J.

    1995-06-01

    In this paper the authors discuss numerical simulations of the Non-Proliferation Experiment (NPE), which was an underground explosion conducted in September 1993 in the volcanic tuff of the Nevada Test Site. The NPE source consisted of 1.29 {times} 10{sup 6} kg of ANFO-emulsion blasting agent, with the approximate energy of 1.1 kt, emplaced 389 m beneath the surface of Rainier Mesa. The authors compare detailed numerical simulations of the NPE with data collected from that experiment, and with calculations of an equally energetic nuclear explosion in identical geology. Calculated waveforms, at ranges out to approximately 1 km, agree moderately well in the time domain with free-field data, and are in qualitative agreement with free-surface records. Comparison of computed waveforms for equally energetic chemical and nuclear sources reveals relatively minor differences beyond the immediate near-source region, with the chemical source having an {approximately}25% greater seismic moment but otherwise indistinguishable (close-in) seismic source properties. 41 refs., 67 figs., 7 tabs.

  5. Comparison of one- and three-dimensional soil vapour extraction experiments.

    PubMed

    Duggal, A; Zytner, R G

    2009-04-01

    Soil vapour extraction (SVE) is a common remediation technology used to clean soil contaminated with gasoline. Even though many studies have been completed on SVE, the majority of them have been at the one-dimensional level, while SVE occurs at a three dimensional level. Accordingly, one-dimensional and radial column laboratory experiments were completed to determine if the experimental configuration made a difference with the results. Two soil types were tested at a variety of flow rates. The contaminant used was toluene. The results were analysed both qualitatively and quantitatively. Analysis of both systems showed them to provide good mass closures. On a qualitative basis, the one-dimensional experiments showed that an increase in flow rates did not result in significant mass transfer limitations for the air flow rates tested. The radial columns revealed mass transfer limitations that were not seen in the one-dimensional column. Quantitative comparison through back-calculated mass transfer coefficients confirmed the trends seen in the qualitative analysis. It is unclear if this is a result of geometry of the radial column or the higher velocities within the radial column. The results indicate that further work with the radial column is necessary to better understand field SVE systems, making it possible to better predict field performance.

  6. DIRECT COMPARISON BETWEEN MODELING AND EXPERIMENT: AN (ALPHA)-Fe ION IMPLANTATION STUDY

    SciTech Connect

    Marian, J; Wirth, B D; Perlado, J M; Diaz de la Rubia, T; Schaublin, R; Lodi, D; Hernandez, M; de Diego, G; Stoller, R E

    2001-01-25

    Advances in computational capability and modeling techniques, as well as improvements in experimental characterization methods offer the possibility of directly comparing modeling and experiment investigations of irradiation effects in metals. As part of a collaboration among the Instituto de Fusion Nuclear (DENIM), Lawrence Livermore National Laboratory (LLNL) and CIEMAT, single and polycrystalline {alpha}-Fe samples have been irradiated with 150 keV Fe-ions to doses up to several dpa. The irradiated microstructure is to be examined with both transmission electron microscopy (TEM) and positron annihilation spectroscopy (PAS). Concurrently, we have modeled the damage accumulation in Fe under these irradiation conditions using a combination of molecular dynamics (MD) and kinetic Monte Carlo (KMC). We aim to make direct comparison between the simulation results and the experiments by simulating TEM images and estimating positron lifetimes for the predicted microstructures. While the identity of the matrix defect features cannot be determined from TEM observations alone, we propose that both large self-interstitial loops, trapped at impurities within the material, and small, spherical nanovoids form.

  7. Comparison of Spacecraft Contamination Models with Well-Defined Flight Experiment

    NASA Technical Reports Server (NTRS)

    Pippin, G. H.

    1998-01-01

    The report presents analyzed surface areas on particular experiment trays from the Long Duration Exposure Facility (LDEF) for silicone-based molecular contamination. The trays for examination were part of the Ultra-Heavy Cosmic Ray Experiment (UHCRE). These particular trays were chosen because each tray was identical to the others in construction, and the materials on each tray were well known, documented, and characterized. In particular, a known specific source of silicone contamination was present on each tray. Only the exposure conditions varied from tray to tray. The results of post-flight analyses of surfaces of three trays were compared with the predictions of the three different spacecraft molecular contamination models. Phase one tasks included: 1) documenting the detailed geometry of the hardware; 2) determining essential properties of the anodized aluminum, Velcro(Tm), silverized Teflon(Tm), silicone gaskets, and DC6-1104(Tm) silicone adhesive materials used to make the trays, tray covers, and thermal control blankets; 3) selecting and removing areas from each tray; and 4) beginning surface analysis of the selected tray walls. Phase two tasks included: 1) completion of surface analysis measurements of the selected tray surface, 2) obtaining auger depth profiles at selected locations, and 3) running versions of the ISEM, MOFLUX, and PLIMP (Plume Impingement) contamination prediction models and making comparisons with experimental results.

  8. Nonlinear gyrokinetic simulations of the I-mode high confinement regime and comparisons with experiment

    SciTech Connect

    White, A. E. Howard, N. T.; Creely, A. J.; Chilenski, M. A.; Greenwald, M.; Hubbard, A. E.; Hughes, J. W.; Marmar, E.; Rice, J. E.; Sierchio, J. M.; Sung, C.; Walk, J. R.; Whyte, D. G.; Mikkelsen, D. R.; Edlund, E. M.; Kung, C.; Holland, C.; Candy, J.; Petty, C. C.; Reinke, M. L.; and others

    2015-05-15

    For the first time, nonlinear gyrokinetic simulations of I-mode plasmas are performed and compared with experiment. I-mode is a high confinement regime, featuring energy confinement similar to H-mode, but without enhanced particle and impurity particle confinement [D. G. Whyte et al., Nucl. Fusion 50, 105005 (2010)]. As a consequence of the separation between heat and particle transport, I-mode exhibits several favorable characteristics compared to H-mode. The nonlinear gyrokinetic code GYRO [J. Candy and R. E. Waltz, J Comput. Phys. 186, 545 (2003)] is used to explore the effects of E × B shear and profile stiffness in I-mode and compare with L-mode. The nonlinear GYRO simulations show that I-mode core ion temperature and electron temperature profiles are more stiff than L-mode core plasmas. Scans of the input E × B shear in GYRO simulations show that E × B shearing of turbulence is a stronger effect in the core of I-mode than L-mode. The nonlinear simulations match the observed reductions in long wavelength density fluctuation levels across the L-I transition but underestimate the reduction of long wavelength electron temperature fluctuation levels. The comparisons between experiment and gyrokinetic simulations for I-mode suggest that increased E × B shearing of turbulence combined with increased profile stiffness are responsible for the reductions in core turbulence observed in the experiment, and that I-mode resembles H-mode plasmas more than L-mode plasmas with regards to marginal stability and temperature profile stiffness.

  9. Free-field ground motions for the nonproliferation experiment: Preliminary comparisons with nearby nuclear events

    SciTech Connect

    Olsen, K.H.; Peratt, A.L.

    1994-06-01

    Since 1987, we have installed fixed arrays of tri-axial accelerometers in the fire-field near the shot horizons for low-yield ({le} 20 kt) nuclear events in the N-tunnel complex beneath Rainier Mesa. For the Nonproliferation Experiment (NPE) we augmented the array to achieve 23 free-field stations. Goals are: (a) to examine robustness and stability of various free-field source function estimates -- e.g., reduced displacement potentials (RDP) and spectra; (b) to compare close-in with regional estimates to test whether detailed close-in free-field and/or surface ground motion data can improve predictability of regional-teleseismic source functions; (c) to provide experimental data for checking two-dimensional numerical simulations. We report preliminary comparisons between experimental free-field data for NPE (1993) and three nearby nuclear events (MISTY ECHO, 1988; MINERAL QUARRY, 1990; HUNTERS TROPHY, 1992). All four working points are within 1 km of each other in the same wet tuff bed, thus reducing concerns about possible large differences in material properties between widely separated shots. Initial comparison of acceleration and velocity seismograms for the four events reveals: (1) There is a large departure from the spherical symmetry commonly assumed in analytic treatments of source theory; both vertical and tangential components are surprisingly large. (2) All shots show similar first-peak particle-velocity amplitude decay rates suggesting significant attenuation even in the supposedly purely elastic region. (3) Sharp (>20 Hz) arrivals are not observed at tunnel level from near-surface pP reflections or spall-closure sources -- but broadened peaks are seen that suggest more diffuse reflected energy from the surface and from the Paleozoic limestone basement below tunnel level.

  10. Comparison of experiments and simulations for zero pressure gradient turbulent boundary layers at moderate Reynolds numbers

    NASA Astrophysics Data System (ADS)

    Örlü, Ramis; Schlatter, Philipp

    2013-06-01

    A detailed comparison between recent direct numerical simulation (DNS) and experiments of a turbulent boundary layer under zero pressure gradient at Re θ = 2,500 and 4,000 (based on the free-stream velocity and momentum-loss thickness) is presented. The well-resolved DNS is computed in a long spatial domain (Schlatter and Örlü in J Fluid Mech 659:116, 2010a), including the disturbance strip, while the experiments consist of single hot-wire probe and oil-film interferometry measurements. Remarkably, good agreement is obtained for integral quantities such as skin friction and shape factor, as well as mean and fluctuating streamwise velocity profiles, higher-order moments and probability density distributions. The agreement also extends to spectral/structural quantities such as the amplitude modulation of the small scales by the large-scale motion and temporal spectral maps throughout the boundary layer. Differences within the inner layer observed for statistical and spectral quantities could entirely be removed by spatially averaging the DNS to match the viscous-scaled length of the hot-wire sensor, thereby explaining observed differences solely by insufficient spatial resolution of the hot-wire sensor. For the highest Reynolds number, Re θ = 4,000, the experimental data exhibit a more pronounced secondary spectral peak in the outer region ( y/ δ 99 = 0.1) related to structures with length on the order of 5-7 boundary layer thicknesses, which is weaker and slightly moved towards lower temporal periods in the DNS. The cause is thought to be related to the limited spanwise box size which constrains the growth of the very large structures. In the light of the difficulty to obtain "canonical" flow conditions, both in DNS and the wind tunnel where effects such as boundary treatment, pressure gradient and turbulence tripping need to be considered, the present cross-validation of the data sets, at least for the present Re θ -range, provides important reference data

  11. Social comparison processes, narrative mapping and their shaping of the cancer experience: a case study of an elite athlete.

    PubMed

    Sparkes, Andrew C; Pérez-Samaniego, Víctor; Smith, Brett

    2012-09-01

    Drawing on data generated by life history interviews and fieldwork observations we illuminate the ways in which a young elite athlete named David (a pseudonym) gave meaning to his experiences of cancer that eventually led to his death. Central to this process were the ways in which David utilized both social comparisons and a narrative map provided by the published autobiography of Lance Armstrong (2000). Our analysis reveals the selective manner in which social comparison processes operated around the following key dimensions: mental attitude to treatment; the sporting body; the ageing body; and physical appearance. The manner in which different comparison targets were chosen, the ways in which these were framed by Armstrong's autobiography, and the work that the restitution narrative as an actor did in this process are also examined. Some reflections are offered regarding the experiential consequences of the social comparison processes utilized by David when these are shaped by specific forms of embodiment and selective narrative maps of cancer survival.

  12. Microstructure of ambient and supercritical water. Direct comparison between simulation and neutron scattering experiments

    SciTech Connect

    Chialvo, A.A.; Cummings, P.T. |

    1996-01-25

    Molecular dynamics simulations of SPC, SPC/E, TIP4P, and ST2 water models are performed at ambient and two supercritical conditions make a direct comparison with recent microstructural data obtained by neutron diffraction with isotopic substitution (NDIS) experiments. The models generally fail to accurately predict details of the NDIS results at supercritical conditions, even though they are somewhat successful at ambient conditions. The failure is not as pronounced as that expected by Postorino et al. because of an unusual density dependence in the structure predicted by two of the models. We also evaluate a model for supercritical water denoted SPCG, a modification of the SPC and SPC/E models, in which the dipole moment is reduced to the bare dipole moment of water. For this model, the predicted structure at supercritical conditions is in much better agreement with experiment. A geometric definition of hydrogen bonding is used to gain insight into the angular dependence of the H...O pair distribution function g{sub OH}(r,{omega}). The simulation results for the five models indicate a strong orientational dependence for the g{sub OH}(r,{omega}) along the H-bonding orientations, with an approximately constant relative strength from ambient to supercritical conditions, suggesting that the angle-averaged radial distribution function, g{sub OH}(r), and its volume integral over the first solvation shell, n{sub OH}(r), may not in themselves be good measures of the strength of the H-bonding. 46 refs., 15 figs., 2 tabs.

  13. Contrail Cirrus Forecasts for the ML-CIRRUS Experiment and Some Comparison Results

    NASA Astrophysics Data System (ADS)

    Schumann, Ulrich; Graf, Kaspar; Bugliaro, Luca; Dörnbrack, Andreas; Giez, Andreas; Jurkat, Tina; Kaufmann, Stefan; Krämer, Martina; Minikin, Andreas; Schäfler, Andreas; Voigt, Christiane; Wirth, Martin; Zahn, Andreas; Ziereis, Helmut

    2015-04-01

    Model simulations with the contrail cirrus prediction model CoCiP driven by numerical weather prediction (NWP) data provided from the European Centre for Medium Range Forecasts (ECMWF) and global aircraft waypoint data show a mean computed cover (for optical depth larger than 0.1) of 0.23% globally, and 5.4% over mid Europe (Schumann and Graf, JGR, 2013). The computed mean longwave radiative forcing (RF) reaches 3 W m-2 over mid Europe (10°W-20°E and 40°N-55°N), and 0.13 W m-2 globally. The global net RF is about 40-60% smaller because of compensating shortwave cooling induced by contrails during daytime. The results depend on several model details such as the number of ice particles forming from aircraft soot emissions, the contrail plume dispersion, ice particle sedimentation etc., all influencing contrail life time and their optical properties. The quantitative results depend also strongly on ambient relative humidity, vertical motion and on ice water content of other cirrus predicted by the NWP model. In order to test and possibly improve this and other contrail models, high-quality observations are needed to which multi-parameter model output can be compared. The Mid-Latitude Cirrus Experiment ML-CIRRUS was performed (see C. Voigt et al., this conference) with a suite of in-situ and Lidar instruments for airborne measurements on the research aircraft HALO. Before and during the mission, CoCiP was run daily to provide 3-days forecasts of contrail cover using operational ECMWF forecasts and historical traffic data. CoCiP forecast output was made available in an internet tool twice a day for experiment planning. The one-day and two-day contrail forecasts often showed only small differences. Still, most recent forecasts and detailed satellite observations results were transmitted via satellite link to the crew for onboard campaign optimization. After the campaign, a data base of realistic air traffic data has been setup from various sources, and CoCiP was

  14. Internal Rotation of Methylcyclopropane and Related Molecules: Comparison of Experiment and Theory.

    PubMed

    Ocola, Esther J; Laane, Jaan

    2016-09-22

    The internal rotation about the single bond connecting a cyclopropyl ring to a CH3, SiH3, GeH3, NH2, SH, or OH group was investigated. Both CCSD/cc-pVTZ and MP2/cc-pVTZ ab initio calculations were performed to predict the structures of these molecules and their internal rotation potential energy functions in terms of angles of rotation. The barriers to internal rotation for the CH3, SiH3, and GeH3 molecules from the calculations agree well with the experimental ones, within -11% to +1% for CCSD/cc-pVTZ and -4% to +9% for MP2/cc-pVTZ. Comparisons between theory and experiment were also performed for propylene oxide and propylene sulfide, and the agreements were very good. Theoretical calculations were performed to compute the internal rotation potential energy function for cyclopropanol, and these were used to guide the determination of a potential function based on experimental data. This molecule has two equivalent synclinal (gauche) conformers with an estimated barrier of 759 cm(-1) (9.1 kJ/mol) between them. The minima are at internal rotation angles of the OH group of 109° and 251°. The theoretical potential functions for cyclopropanethiol and cyclopropylamine were also calculated, and these agree reasonably well with previous experimental studies. PMID:27571027

  15. Post-Shot Simulations of NIC Experiments with Comparison to X-ray Measurements

    NASA Astrophysics Data System (ADS)

    Eder, David; Jones, Oggie; Suter, Larry; Moore, Alastair; Schneider, Marilyn

    2012-10-01

    National Ignition Campaign experiments at NIF are ongoing and post-shot simulations play an important role in understanding the physical processes occurring in the quest for demonstrating fusion burn. In particular, it is important to understand the x-ray environment inside the hohlraum targets, which is studied using various x-ray diagnostics. The Dante instrument measures the time dependent x-ray emission escaping out of the hohlraum laser entrance holes (LEHs) and the SXI instrument provides a time-integrated image of both soft and hard x-rays. We compare calculated total x-ray emission with Dante data as well as the relative high energy Mband emission that contributes to capsule preheat. We correct our calculated x-ray emission to account for differences between simulation and data on LEH closure using SXI data. We provide results for both ``standard candle'' simulation with no added multipliers and for simulations with time-dependent multipliers that are used to obtain agreement with shock timing and implosion velocity data. The physics justification for the use of multipliers is to account for potential missing energy or incorrect ablation modeling. The relative importance of these two effects can be studied through comparison of post-shot simulations with x-ray measurements.

  16. Stratospheric aerosol and gas experiments I and II comparisons with ozonesondes

    SciTech Connect

    Veiga, R.E.; Cunnold, D.M.; Chu, W.P.

    1995-05-20

    Ozone profiles measured by the Stratospheric Aerosol and Gas Experiments (SAGE) I and II are compared with ozonesonde profiles at 24 stations over the period extending from 1979 through 1991. Ozonesonde/satellite differences at 21 stations with SAGE II overpasses were computed down to 11.5 km in the midlatitudes, to 15.5 km in the lower latitudes, and for nine stations with SAGE I overpasses down to 15.5 km. The set of individual satellite and ozonesonde profile comparisons most closely colocated in time and space shows mean absolute differences relative to the satellite measurement of 6 {plus_minus} 2% for SAGE II and 8 {plus_minus}3% for SAGE I. The ensemble of ozonesonde/satellite differences, when averaged over all altitudes, shows that for SAGE II, 70% were less than 5%, whereas for SAGE I, 50% were less than 5%. The best agreement occurred in the altitude region near the ozone density maximum where almost all the relative differences were less than 5%. Most of the statistically significant differences occurred below the ozone maximum down to the tropopause in the region of steepest ozone gradients and typically ranged between 0 and {minus}20%. Correlations between ozone and aerosol extinction in the northern midlatitudes indicate that aerosols had no discernible impact on the ozonesonde/satellite differences and on the stratosphere during 1984 to mid-1991. 42 refs., 8 figs., 1 tab.

  17. Simulating thermal explosion of octahydrotetranitrotetrazine-based explosives: Model comparison with experiment

    NASA Astrophysics Data System (ADS)

    Yoh, Jack J.; McClelland, Matthew A.; Maienschein, Jon L.; Nichols, Albert L.; Tarver, Craig M.

    2006-10-01

    A model comparison with measurements for the thermal, chemical, and mechanical behaviors in a thermal explosion experiment is presented. Confined high explosives (HEs) are heated at a rate of 1°C/h until an explosion is observed. The heating, ignition, and deflagration phases are modeled using an arbitrarily Lagrangian-Eulerian (ALE3D) code that can handle a wide range of time scales that vary from a structural to a hydrodynamic time scale. During the preignition phase, quasistatic mechanics and diffusive thermal transfer from a heat source to the HE are coupled with the finite chemical reactions that include both endothermic and exothermic processes. Once the HE ignites, a hydrodynamic calculation is performed as a burn front propagates through the HE. Two octahydrotetranitrotetrazine (HMX)-based explosives, LX-04 and LX-10, are considered, whose chemical-thermal-mechanical models are constructed based on measurements of thermal and mechanical properties along with small-scale thermal explosion measurements. The present HMX modeling work shows the violence calculations with thermal predictions associated with a confined thermal explosion test. The simulated dynamic response of HE confinement during the explosive phase is compared to measurements in larger scale thermal explosion tests. The explosion temperatures for both HEs are predicted to within 1°C. Calculated and measured wall strains provide an indication of vessel pressurization during the heating phase and violence during the explosive phase.

  18. Basic relationships in precipitating antigen-antibody systems: a comparison of a simple theory with experiment.

    PubMed

    Gronski, P; Seiler, F R

    1984-11-01

    Theoretical predictions from a simple theory for a homogeneous system with respect to some fundamental functional relations between amount of precipitate or extent of turbidity, initial antigen (Ag) respectively antibody (Ab) concentration, and solubility of immune complexes (ICs) are discussed in comparison with experimental results in a heterogeneous system. Experiments were performed with the aim to render possible and intuitive picture of the relationships considering different aspects. It was found that the theory derived from the equilibrium state of the reaction is also able to describe the non-equilibrium state in a qualitatively correct manner. The influence of Ab affinity on precipitation is discussed. Moreover, it is shown that the theory developed by Pauling et al. in the 1940's although too simple in several details, does, however, consider the most important basic principles of more extensive theories developed by other authors. Precisely because of its simplicity, this model may be a useful help in the discussion of precipitate formation on a molecular level.

  19. Defect printability of alternating phase-shift mask: a critical comparison of simulation and experiment

    NASA Astrophysics Data System (ADS)

    Ozawa, Ken; Komizo, Tooru; Kikuchi, Koji; Ohnuma, Hidetoshi; Kawahira, Hiroichi

    2002-07-01

    An alternative phase shift mask (alt-PSM) is a promising device for extending optical lithography to finer design rules. There have been few reports, however, on the mask's ability to identify phase defects. We report here an alt-PSM of a dual-trench type for KrF exposure, with programmed quartz defects used to evaluate defect printability by measuring aerial images with a Zeiss MSM100 measuring system. The experimental results are simulated using the TEMPEST program. First, a critical comparison of the simulation and the experiment is conducted. The actual measured topography of quartz defects are used in the simulation. Moreover, a general simulation study on defect printability using an alt-PSM for ArF exposure is conducted. The defect dimensions, which produce critical CD errors are determined by simulation that takes into account the full 3-dimensional structure of phase defects as well as a simplified structure. The critical dimensions of an isolated defect identified by the alt-PSM of a single-trench type for ArF exposure are 240 nm in bottom diameter and 50 degrees in height (phase) for the cylindrical shape and 240 nm in bottom diameter and 90 degrees in height (phase) for the rotating trapezoidal shape, where the CD error limit is +/- 5%.

  20. Determination of forces in a magnetic bearing actuator - Numerical computation with comparison to experiment

    NASA Technical Reports Server (NTRS)

    Knight, J. D.; Xia, Z.; Mccaul, E.; Hacker, H., Jr.

    1992-01-01

    Calculations of the forces exerted on a journal by a magnetic bearing actuator are presented, along with comparisons to experimentally measured forces. The calculations are based on two-dimensional solutions for the flux distribution in the metal parts and free space, using finite but constant permeability in the metals. Above a relative permeability of 10,000 the effects of changes in permeability are negligible, but below 10,000 decreases in permeability cause significant decreases in the force. The calculated forces are shown to depend on the metal permeability more strongly when the journal is displaced from its centered position. The predicted forces in the principal attractive direction are in good agreement with experiment when a relatively low value of permeability is chosen. The forces measured normal to the axis of symmetry when the journal is displaced from that axis, however, are significantly higher than predicted by theory, even with a value of relative permeability larger than 5000. These results indicate a need for further work including nonlinear permeability distributions.

  1. Comparison of Time Domain Reflectometry Performance Factors for Several Dielectric Geometries: Theory and Experiments

    NASA Astrophysics Data System (ADS)

    Maheshwarla, S. V.; Venkatasubramanian, R.; Boehm, Robert F.

    1995-08-01

    We propose three nontraditional dielectric geometries and present an experimental and theoretical analysis and comparison of time domain reflectometry (TDR) performances for them. The traditional geometry (the probes inserted in material of essentially infinite extent) is compared to three nontraditional geometries where the probes are affixed outside of a core sample, inside of a bore, or flat on the surface of a semi-infinite solid. Our derivation relates the velocity of electromagnetic wave propagation to the complex permittivities and permeabilities of the media and the geometry for the three nontraditional configurations. Experimental results for air, styrofoam, dry sand, wet sand of varying water content, nylon, dry wood, and ferromagnetic steel are obtained for the three proposed configurations and are in fair agreement with the literature within the experimental uncertainties. Through experiments and theoretical analysis, the TDR performance is found to be the same within the experimental uncertainties for the three nontraditional geometries. The proposed geometries yield slightly lower sensitivities compared to the traditional geometry. Advantages and disadvantages of the geometries compared to the traditional geometry are also discussed.

  2. Numerical modeling of exhaust smoke dispersion for a generic frigate and comparisons with experiments

    NASA Astrophysics Data System (ADS)

    Ergin, Selma; Dobrucalı, Erinç

    2014-06-01

    The exhaust smoke dispersion for a generic frigate is investigated numerically through the numerical solution of the governing fluid flow, energy, species and turbulence equations. The main objective of this work is to obtain the effects of the yaw angle, velocity ratio and buoyancy on the dispersion of the exhaust smoke. The numerical method is based on the fully conserved control-volume representation of the fully elliptic Navier-Stokes equations. Turbulence is modeled using a two-equation ( k- ɛ) model. The flow visualization tests using a 1/100 scale model of the frigate in the wind tunnel were also carried out to determine the exhaust plume path and to validate the computational results. The results show that down wash phenomena occurs for the yaw angles between ψ =10° and 20°. The results with different exhaust gas temperatures show that the buoyancy effect increases with the increasing of the exhaust gas temperature. However, its effect on the plume rise is less significant in comparison with its momentum. A good agreement between the predictions and experiment results is obtained.

  3. Comparison of In Situ Aerosol Data from the ACE-Asia 2001 Experiment

    NASA Astrophysics Data System (ADS)

    Knobelspiesse, K. D.; Pietras, C.; Miller, M. A.; Reynolds, R. M.; Frouin, R.; Quinn, P. K.; Deschamps, P. Y.; Werdell, P. J.; Fargion, G. S.

    2002-05-01

    The Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia) is an international, multidisciplinary project to further knowledge about atmospheric aerosols. ACE-Asia included an intensive field measurement campaign during the spring of 2001 off the coasts of China, Japan and Korea. The Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) Project participated in the ACE-Asia cruise of the R/V Ronald H. Brown, which departed from Hawaii on 2001/03/15, sailed west to the Sea of Japan, and finished in Yokosuka, Japan on 2001/04/19. The SIMBIOS Project compares and merges data projects from multiple ocean color missions. As In Situ data are essential for merger and comparison of satellite ocean color measurements, the Project is interested in instrumentation devopment and data base building. The SeaWiFS Bio-optical Archive and Storage System (SeaBASS) is the database used and maintained by the SIMBIOS project. The ACE-Asia cruise was an excellent opportunity to compare data from a variety of maritime sun photometers, as several aerosol conditions were experienced. These included low Aerosol Optical Thickness (AOT) maritime conditions near Hawaii and extremely high AOT dust conditions in the Sea of Japan. Concurrant measurements were made with the PREDE POM-01 Mark II radiometer, a Laboratoire d'Optique Atmosphérique (LOA) SIMBAD, a Laboratorie d'Optique Atmosphérique (LOA) SIMBAD-a, two Solar Light, Inc. Microtops II's, and Brookhaven National Laboratory's Fast Rotating Shadowband Radiometer (FRSR). In addition, a Micro Pulse Lidar (MPL) was deployed that provides vertical aerosol distributions. Data were processed utilizing new algorithms to screen errors due to improper pointing at the sun, a problem previously recognized for the Microtops II. Comparisons of AOT at 500nm and Angstrom Exponent were made for all the instruments. The hand held, direct solar sun photometers (Microtops II, SIMBAD and SIMBADa

  4. Comparison among five hydrodynamic codes with a diverging-converging nozzle experiment

    SciTech Connect

    L. E. Thode; M. C. Cline; B. G. DeVolder; M. S. Sahota; D. K. Zerkle

    1999-09-01

    A realistic open-cycle gas-core nuclear rocket simulation model must be capable of a self-consistent nozzle calculation in conjunction with coupled radiation and neutron transport in three spatial dimensions. As part of the development effort for such a model, five hydrodynamic codes were used to compare with a converging-diverging nozzle experiment. The codes used in the comparison are CHAD, FLUENT, KIVA2, RAMPANT, and VNAP2. Solution accuracy as a function of mesh size is important because, in the near term, a practical three-dimensional simulation model will require rather coarse zoning across the nozzle throat. In the study, four different grids were considered. (1) coarse, radially uniform grid, (2) coarse, radially nonuniform grid, (3) fine, radially uniform grid, and (4) fine, radially nonuniform grid. The study involves code verification, not prediction. In other words, the authors know the solution they want to match, so they can change methods and/or modify an algorithm to best match this class of problem. In this context, it was necessary to use the higher-order methods in both FLUENT and RAMPANT. In addition, KIVA2 required a modification that allows significantly more accurate solutions for a converging-diverging nozzle. From a predictive point of view, code accuracy with no tuning is an important result. The most accurate codes on a coarse grid, CHAD and VNAP2, did not require any tuning. Their main comparison among the codes was the radial dependence of the Mach number across the nozzle throat. All five codes yielded a very similar solution with fine, radially uniform and radially nonuniform grids. However, the codes yielded significantly different solutions with coarse, radially uniform and radially nonuniform grids. For all the codes, radially nonuniform zoning across the throat significantly increased solution accuracy with a coarse mesh. None of the codes agrees in detail with the weak shock located downstream of the nozzle throat, but all the

  5. Inter-storm comparisons from the OSCAR high density network experiment

    NASA Astrophysics Data System (ADS)

    Chapman, E. G.; Luecken, D. J.; Dana, M. T.; Easter, R. C.; Hales, J. M.; Laulainen, N. S.; Thorp, J. M.

    The high density network component of the Oxidation and Scavenging Characteristics of April Rains (OSCAR) experiment combined aircraft, surface and sequential precipitation chemistry measurements to characterize the physicochemical and dynamic features of four storms sampled during an April 1981 field investigation. A surface network of 47 precipitation sampling stations, covering a region roughly 110 km by 110 km, was established in the area surrounding Fort Wayne, Indiana. The network provided temporal and spatial resolution of rainfall chemistry via the use of specially designed automatic sequential bulk precipitation collectors, while aircraft and surface sampling provided measurements of the major aerosols and trace gases in the boundary-layer inflow region. Composite concentration and ion ratio profiles for the events were analyzed to investigate potential pollutant scavenging pathways. This analysis led to the following observations: (i) dryfall deposition during pre-rainfall exposure periods influenced initial sampler stage chemistry; (ii) relative precipitation acidity increased throughout the events; SO 42- and NO 3- were the major contributors to this acidity; (iii) evidence exists for the in-cloud oxidation of SO 2 during Events 3 and 4, while scavenging of HNO 3 and aerosol NO 3- probably produced precipitation NO 3-; (iv) the non-frontal meteorology of Event 3 influenced the precipitation chemistry associated with this storm and led to distinct concentration profiles; (v) an anomalous pattern of NH 4+ concentrations observed during Event 1 cannot be explained by known NH 4+ scavenging behavior or by non-scavenging related influences, such as local source contamination or NH 3 volatilization; (vi) Event 4 is more suitable for analysis by one- and two-dimensional diagnostic wet removal models. Analysis of the other events is complicated by more complex meteorological behavior and, in some cases, a less complete chemistry data set. This paper enlarges on

  6. Comparisons of Transport and Dispersion Model Predictions of the Mock Urban Setting Test Field Experiment

    NASA Astrophysics Data System (ADS)

    Warner, Steve; Platt, Nathan; Heagy, James F.; Jordan, Jason E.; Bieberbach, George

    2006-10-01

    The potential effects of a terrorist attack involving the atmospheric release of chemical, biological, radiological, nuclear, or other hazardous materials continue to be of concern to the United States. The Defense Threat Reduction Agency has developed a Hazard Prediction Assessment Capability (HPAC) that includes initial features to address hazardous releases within an urban environment. Improved characterization and understanding of urban transport and dispersion are required to allow for more robust modeling. In 2001, a scaled urban setting was created in the desert of Utah using shipping containers, and tracer gases were released. This atmospheric tracer and meteorological study is known as the Mock Urban Setting Test (MUST). This paper describes the creation of sets of HPAC predictions and comparisons with the MUST field experiment. Strong consistency between the conclusions of this study and a previously reported HPAC evaluation that relied on urban tracer observations within the downtown area of Salt Lake City was found. For example, in both cases, improved predictions were associated with the inclusion of a simple empirically based urban dispersion model within HPAC, whereas improvements associated with the inclusion of a more computationally intensive wind field module were not found. The use of meteorological observations closest to the array and well above the obstacle array—the sonic anemometer measurements 16 m above ground level—resulted in predictions with the best fit to the observed tracer concentrations. The authors speculate that including meteorological observations or vertical wind profiles above or upwind of an urban region might be a sufficient input to create reasonable HPAC hazard-area predictions.

  7. A comparison of the Stratospheric Aerosol and Gas Experiment II tropospheric water vapor to radiosonde measurements

    SciTech Connect

    Larsen, J.C.; Chiou, E.W. ); Chu, W.P.; McCormick, M.P.; McMaster, L.R. ); Oltmans, S. ); Rind, D. )

    1993-03-20

    Upper tropospheric Stratospheric Aerosol and Gas Experiment II (SAGE II) water vapor observations are compared to correlative radiosonde observations and radiosonde based climatologies. The SAGE II 1987 monthly zonal mean water vapor climatology is compared to both the Global Atmospheric Circulation Statistics (1963-1973) climatology and to the 1987 radiosonde climatology. The clear sky SAGE II climatology is found to be approximately half the level of both the clear/cloudy sky radiosonde climatologies. To determine whether this is realistic for these two different climatologies or includes additional observational and instrumental biases, the authors took the 1987 radiosonde data set and identified approximately 800 correlative profile pairs. The observational biases inherent to SAGE II and the radiosondes produce a set of profile pairs characteristic of clear sky, land conditions. A critical review of the radiosonde measurement capability was carried out to establish the operating range and accuracy in the upper troposphere. The authors show that even with tight coincidence criterion, the quality of the profile pair comparisons varies considerably because of strong water vapor variability occurring on small time and space scales. Annual zonal means calculated from the set of profile pairs again finds SAGE II significantly drier in many latitude bands. Resolving the radiosonde data base by hygrometer type shows this to be true for all hygrometers except for the thin film capacitive type (Vaisala Humicap). For this hygrometer, between 4.5 and 6.5 km SAGE II is drier by approximately 25.%, and from 8.5 to 11.5 km they are nearly equivalent when global annual means are compared. The good agreement with the Vaisala Humicap, currently the most accurate and responsive hygrometer in operational use, suggests existing radiosonde climatologies contain a significant moist bias in the upper troposphere. 31 refs., 16 figs., 6 tabs.

  8. Tomogram-based comparison of geostatistical models: Application to the Macrodispersion Experiment (MADE) site

    NASA Astrophysics Data System (ADS)

    Linde, Niklas; Lochbühler, Tobias; Dogan, Mine; Van Dam, Remke L.

    2015-12-01

    We propose a new framework to compare alternative geostatistical descriptions of a given site. Multiple realizations of each of the considered geostatistical models and their corresponding tomograms (based on inversion of noise-contaminated simulated data) are used as a multivariate training image. The training image is scanned with a direct sampling algorithm to obtain conditional realizations of hydraulic conductivity that are not only in agreement with the geostatistical model, but also honor the spatially varying resolution of the site-specific tomogram. Model comparison is based on the quality of the simulated geophysical data from the ensemble of conditional realizations. The tomogram in this study is obtained by inversion of cross-hole ground-penetrating radar (GPR) first-arrival travel time data acquired at the MAcro-Dispersion Experiment (MADE) site in Mississippi (USA). Various heterogeneity descriptions ranging from multi-Gaussian fields to fields with complex multiple-point statistics inferred from outcrops are considered. Under the assumption that the relationship between porosity and hydraulic conductivity inferred from local measurements is valid, we find that conditioned multi-Gaussian realizations and derivatives thereof can explain the crosshole geophysical data. A training image based on an aquifer analog from Germany was found to be in better agreement with the geophysical data than the one based on the local outcrop, which appears to under-represent high hydraulic conductivity zones. These findings are only based on the information content in a single resolution-limited tomogram and extending the analysis to tracer or higher resolution surface GPR data might lead to different conclusions (e.g., that discrete facies boundaries are necessary). Our framework makes it possible to identify inadequate geostatistical models and petrophysical relationships, effectively narrowing the space of possible heterogeneity representations.

  9. The Impact of a Comparison Curriculum in Algebra I: A Randomized Experiment

    ERIC Educational Resources Information Center

    Star, Jon R.; Rittle-Johnson, Bethany; Durkin, Kelley; Newton, Kristie; Pollack, Courtney; Lynch, Kathleen; Gogolen, Claire

    2013-01-01

    Comparison is a powerful tool that has been shown to improve learning in a variety of domains. In both laboratory studies and small-scale classroom studies, having learners compare and contrast worked examples has been shown to reliably lead to gains in students' knowledge. Comparison is also integral to "best practices" in mathematics…

  10. Comparison of two millennial regional climate experiments over the Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    Gomez-Navarro, J. J.; Montavez, J. P.; Jerez, S.; Jimenez-Guerrero, P.; Lorente-Plazas, R.; Gonzalez-Rouco, J. F.; Zorita, E.

    2010-09-01

    a limited area domain. These models are often used in climate change projections, as they have proven to be able to improve several aspects of the GCM simulations. An important caveat in the use of models to simulate the past climate is the fact that the model has its own internal variability. For this reason, the evolution of the simulated climate has an important charge of uncertainty. In particular, it is not easy to assess whether a simulated cold period is driven by variations in the external forcings (and thus it makes sense when compared with proxy reconstructions) or simply due to a natural fluctuation of the simulation. Regarding this issue, ensembles of simulations may help to assess the internal variability of models. However this kind of ensembles are rare nowadays due to the huge computational cost involved. In this study we present a comparison between two simulations of the past climate performed with a climate version of the regional model MM5. The model domain covers the Iberian Peninsula with a a spatial resolution of 30 km. Both RCM simulations are driven by paleo experiments, ERIK1 and ERIK2, performed with the GCM model ECHOG for the last millennium. Both simulations were forced by the same reconstructions of the evolution of solar power, big volcano events and evolution in the concentration of Greenhouse Gases. The only difference between the two simulations is therefore the initial condition in the GCM. This leads nevertheless to a different evolution of the simulated climate, due to the internal variability of the model. The results indicate that MM5 is capable of improving the reliability of the GCM simulations, in particular the mean values and the variability of precipitation and near-surface temperature. The intercomparison between the two simulations also depicts a number of cold and warm periods that are simultaneous in both experiments; these periods match with some well known cold periods, such as the Maunder Minimum. This good fit

  11. Alternating current dielectrophoresis of core-shell nanoparticles: Experiments and comparison with theory

    NASA Astrophysics Data System (ADS)

    Yang, Chungja

    Nanoparticles are fascinating where physical and optical properties are related to size. Highly controllable synthesis methods and nanoparticle assembly are essential for highly innovative technological applications. Well-defined shaped and sized nanoparticles enable comparisons between experiments, theory and subsequent new models to explain experimentally observed phenomena. Among nanoparticles, nonhomogeneous core-shell nanoparticles (CSnp) have new properties that arise when varying the relative dimensions of the core and the shell. This CSnp structure enables various optical resonances, and engineered energy barriers, in addition to the high charge to surface ratio. Assembly of homogeneous nanoparticles into functional structures has become ubiquitous in biosensors (i.e. optical labeling), nanocoatings, and electrical circuits. Limited nonhomogenous nanoparticle assembly has only been explored. Many conventional nanoparticle assembly methods exist, but this work explores dielectrophoresis (DEP) as a new method. DEP is particle polarization via non-uniform electric fields while suspended in conductive fluids. Most prior DEP efforts involve microscale particles. Prior work on core-shell nanoparticle assemblies and separately, nanoparticle characterizations with dielectrophoresis and electrorotation, did not systematically explore particle size, dielectric properties (permittivity and electrical conductivity), shell thickness, particle concentration, medium conductivity, and frequency. This work is the first, to the best of our knowledge, to systematically examine these dielectrophoretic properties for core-shell nanoparticles. Further, we conduct a parametric fitting to traditional core-shell models. These biocompatible core-shell nanoparticles were studied to fill a knowledge gap in the DEP field. Experimental results (chapter 5) first examine medium conductivity, size and shell material dependencies of dielectrophoretic behaviors of spherical CSnp into 2D and

  12. Comparisons of neutrino event generators from an oscillation-experiment perspective

    SciTech Connect

    Mayer, Nathan

    2015-05-15

    Monte Carlo generators are crucial to the analysis of high energy physics data, ideally giving a baseline comparison between the state-of-art theoretical models and experimental data. Presented here is a comparison between three of final state distributions from the GENIE, Neut, NUANCE, and NuWro neutrino Monte Carlo event generators. The final state distributions chosen for comparison are: the electromagnetic energy fraction in neutral current interactions, the energy of the leading π{sup 0} vs. the scattering angle for neutral current interactions, and the muon energy vs. scattering angle of ν{sub µ} charged current interactions.

  13. Heat*seq: an interactive web tool for high-throughput sequencing experiment comparison with public data

    PubMed Central

    Devailly, Guillaume; Mantsoki, Anna; Joshi, Anagha

    2016-01-01

    Summary: Better protocols and decreasing costs have made high-throughput sequencing experiments now accessible even to small experimental laboratories. However, comparing one or few experiments generated by an individual lab to the vast amount of relevant data freely available in the public domain might be limited due to lack of bioinformatics expertise. Though several tools, including genome browsers, allow such comparison at a single gene level, they do not provide a genome-wide view. We developed Heat*seq, a web-tool that allows genome scale comparison of high throughput experiments chromatin immuno-precipitation followed by sequencing, RNA-sequencing and Cap Analysis of Gene Expression) provided by a user, to the data in the public domain. Heat*seq currently contains over 12 000 experiments across diverse tissues and cell types in human, mouse and drosophila. Heat*seq displays interactive correlation heatmaps, with an ability to dynamically subset datasets to contextualize user experiments. High quality figures and tables are produced and can be downloaded in multiple formats. Availability and Implementation: Web application: http://www.heatstarseq.roslin.ed.ac.uk/. Source code: https://github.com/gdevailly. Contact: Guillaume.Devailly@roslin.ed.ac.uk or Anagha.Joshi@roslin.ed.ac.uk Supplementary information: Supplementary data are available at Bioinformatics online. PMID:27378302

  14. A Comparison of Students' Clinical Experience in Family Medicine and Traditional Clerkships.

    ERIC Educational Resources Information Center

    Parkerson, George R., Jr.; And Others

    1984-01-01

    Experience on the traditional internal medicine, surgery, pediatrics, obstetrics-gynecology, and psychiatry clerkships was compared with the experience on a family medicine clerkship. The family medicine clerkship offered the most experience with circulatory, respiratory, digestive, neurological, musculoskeletal, and skin problems and with…

  15. A Comparison of Technology Experiences Included in Alternative and Traditional Teacher Education Programs

    ERIC Educational Resources Information Center

    Strycker, Jesse D.

    2011-01-01

    Though an educational technology experience is required as part of a traditional teacher education program student's educational preparation, research has been limited into the experiences had by alternative teacher education program students. Similarly, little research has been done comparing technology experiences between both types of teacher…

  16. Comparison of Computational Aeroacoustics Prediction of Acoustic Transmission Through a 3D Stator with Experiment

    NASA Technical Reports Server (NTRS)

    Hixon, Ray; Envia, Edmane; Dahl, Milo; Sutliff, Daniel

    2014-01-01

    In this paper, numerical predictions of acoustic transmission through a 3D stator obtained using the NASA BASS code are compared with experimentally measured data. The influence of vane count and stagger as well as frequency and mode order on the transmission loss is investigated. The data-theory comparisons indicate that BASS can predict all the important trends observed in the experimental data.

  17. Comparison of Computational Aeroacoustics Prediction of Acoustic Transmission Through a 3D Stator With Experiment

    NASA Technical Reports Server (NTRS)

    Hixon, Ray; Envia, Edmane; Dahl, Milo; Sutliff, Daniel L.

    2014-01-01

    In this paper, numerical predictions of acoustic transmission through a 3D stator obtained using the NASA BASS code are compared with experimentally measured data. The influence of vane count and stagger as well as frequency and mode order on the transmission loss is investigated. The data-theory comparisons indicate that BASS can predict all the important trends observed in the experimental data.

  18. A Comparison of Sexual Coercion Experiences Reported by Men and Women in Prison

    ERIC Educational Resources Information Center

    Struckman-Johnson, Cindy; Struckman-Johnson, David

    2006-01-01

    Comparisons were made between self-reports from 382 men and 51 women who had experienced sexual coercion while incarcerated. Victim data were obtained from a sample of 1,788 male inmates and 263 female inmates who responded to an anonymous written survey distributed in 10 midwestern prisons. Men reported that their perpetrators in worst-case…

  19. GaMin’11 – an international inter-laboratory comparison for geochemical CO₂ - saline fluid - mineral interaction experiments

    SciTech Connect

    Ostertag-Henning, C.; Risse, A.; Thomas, B.; Rosenbauer, R.; Rochelle, C.; Purser, G.; Kilpatrick, A.; Rosenqvist, J.; Yardley, B.; Karamalidis, A.; Griffith, C.; Hedges, S.; Dilmore, R.; Goodman, A.; Black, J.; Haese, R.; Deusner, C.; Bigalke, N.; Haeckel, M.; Fischer, S.; Liebscher, A.; Icenhower, J. P.; Daval, D.; Saldi, G. D.; Knauss, K. G.; Schmidt, M.; Mito, S.; Sorai, M.; Truche, L.

    2014-12-31

    Due to the strong interest in geochemical CO₂-fluid-rock interaction in the context of geological storage of CO₂ a growing number of research groups have used a variety of different experimental ways to identify important geochemical dissolution or precipitation reactions and – if possible – quantify the rates and extent of mineral or rock alteration. In this inter-laboratory comparison the gas-fluid-mineral reactions of three samples of rock-forming minerals have been investigated by 11 experimental labs. The reported results point to robust identification of the major processes in the experiments by most groups. The dissolution rates derived from the changes in composition of the aqueous phase are consistent overall, but the variation could be reduced by using similar corrections for changing parameters in the reaction cells over time. The comparison of experimental setups and procedures as well as of data corrections identified potential improvements for future gas-fluid-rock studies.

  20. Electron transport and energy degradation in the ionosphere: Evaluation of the numerical solution, comparison with laboratory experiments and auroral observations

    NASA Technical Reports Server (NTRS)

    Lummerzheim, D.; Lilensten, J.

    1994-01-01

    Auroral electron transport calculations are a critical part of auroral models. We evaluate a numerical solution to the transport and energy degradation problem. The numerical solution is verified by reproducing simplified problems to which analytic solutions exist, internal self-consistency tests, comparison with laboratory experiments of electron beams penetrating a collision chamber, and by comparison with auroral observations, particularly the emission ratio of the N2 second positive to N2(+) first negative emissions. Our numerical solutions agree with range measurements in collision chambers. The calculated N(2)2P to N2(+)1N emission ratio is independent of the spectral characteristics of the incident electrons, and agrees with the value observed in aurora. Using different sets of energy loss cross sections and different functions to describe the energy distribution of secondary electrons that emerge from ionization collisions, we discuss the uncertainties of the solutions to the electron transport equation resulting from the uncertainties of these input parameters.

  1. Sharing the Holocaust Experience: A Comparison of Communication Patterns in Two Groups of Survivors.

    ERIC Educational Resources Information Center

    Kav-Venaki, Sophie; And Others

    This study focuses on the communication patterns (that is, talking of individual experiences and knowledge of other's experiences) of Holocaust related issues in the families of survivors and investigates the consequences of these patterns as reflected in the descendants' knowledge about the Holocaust and their attitudes toward its survivors. A…

  2. A Comparison of Premenarcheal Expectations and Postmenarcheal Experiences in Chinese Early Adolescents

    ERIC Educational Resources Information Center

    Tang, Catherine So-Kum; Yeung, Dannii Y. L.; Lee, Antoinette Marie

    2004-01-01

    The present study examined Chinese early adolescents' expectations and experiences of their first menstruation. It included 952 participants, 476 premenarcheal and 476 postmenarcheal girls matched by age and by grade level. Results showed that compared to experiences of postmenarcheal girls, premenarcheal girls anticipated more negative emotional…

  3. Comparison of Sexual Experience and Behavior between Bipolar Outpatients and Outpatients without Mood Disorders

    PubMed Central

    Downey, Jennifer; Friedman, Richard C.; Haase, Elizabeth; Goldenberg, David; Bell, Robinette; Edsall, Sidney

    2016-01-01

    Sexual behavior over the past year of 32 outpatients with Bipolar disorder is compared to that of 44 Comparison patients that had never had an episode of affective illness. Subjects were outpatients treated with drugs and psychotherapy in routine office practice. Differences in sexual behavior between the two groups as a whole were minimal, but meaningful differences emerged when subgroups were compared. Compared to control men, Bipolar men had had more partners in the last year and were more likely to have had sex without condoms. Compared to Bipolar females, Bipolar males had more sex partners, had more sex with strangers, and were more likely to have engaged in homosexual behavior. Even so, some patients in the Comparison group also had engaged in risky sexual behavior. They had failed to use condoms and had had sex with strangers and prostitutes during the previous year. PMID:27190984

  4. Flight/ground sample comparison relating to flight experiment M552, exothermic brazing

    NASA Technical Reports Server (NTRS)

    Heine, R. W.; Adams, C. M.; Siewert, T. A.

    1973-01-01

    Comparisons were made between Skylab and ground-based specimens of nickel and stainless steel which were vacuum brazed using silver-copper-lithium alloy with various joint configurations. It was established that the absence of gravity greatly extends the scope of brazing since capillary flow can proceed without gravity interference. There was also evidence of enhanced transport, primarily in that liquid silver copper alloy dissolves nickel to a much greater extent in the zero gravity environment.

  5. Cognitive Experiences Reported by Borderline Patients and Axis II Comparison Subjects: A 16-year Prospective Follow-up Study

    PubMed Central

    Zanarini, Mary C.; Frankenburg, Frances R.; Wedig, Michelle M.; Fitzmaurice, Garrett M.

    2013-01-01

    Objective This study assesses three main types of cognition: nonpsychotic thought (odd thinking, unusual perceptual experiences, and non-delusional paranoia), quasi-psychotic thought, and true-psychotic thought in borderline patients followed prospectively for 16 years. It also compares the rates of these disturbed cognitions to those reported by axis II comparison subjects. Method The cognitive experiences of 362 inpatients—290 borderline patients and 72 axis II comparison subjects—were assessed at study entry using the cognitive section of the Revised Diagnostic Interview for Borderlines. Their cognitive experiences were reassessed every two years using the same interview. Results Each of the five main types of thought studied was reported by a significantly higher percentage of borderline patients than axis II comparison subjects over time. Each of these types of thought, except true-psychotic thought, declined significantly over time for those in both groups. Eleven of the 17 more specific forms of thought studied were also reported by a significantly higher percentage of borderline patients over the years of follow-up: magical thinking, overvalued ideas, recurrent illusions, depersonalization, derealization, undue suspiciousness, ideas of reference, other paranoid ideation, quasi-psychotic delusions, quasi-psychotic hallucinations, and true-psychotic hallucinations. Fourteen specific forms of thought were found to decline significantly over time for those in both groups: all forms of thought mentioned above except true-psychotic hallucinations plus marked superstitiousness, sixth sense, telepathy, and clairvoyance. Conclusions Disturbed cognitions are common among borderline patients and distinguishing for the disorder. They also decline substantially over time but remain a problem, particularly those of a nonpsychotic nature. PMID:23558452

  6. Possibilities of paired comparison of receptor binding parameters obtained in a single experiment

    SciTech Connect

    Mashilova, K.V.; Kiriakov, G.V.; Malin, K.M.; Rozhanets, V.V.

    1987-09-01

    The authors explore the use of comparing control and experimental groups on the basis of extrapolation parameters obtained from a single pair of experiments. One of the experiments study the parameters of specific binding of /sup 3/H-D-ala-2-enkephelin-5-D-leucine in the striatum of different groups of rats. The analysis was done by the Cornish-Bowden method.

  7. Results of GEANT simulations and comparison with first experiments at DANCE.

    SciTech Connect

    Reifarth, R.; Bredeweg, T. A.; Browne, J. C.; Esch, E. I.; Haight, R. C.; O'Donnell, J. M.; Kronenberg, A.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wilhelmy, J. B.; Wouters, J. M.

    2003-07-29

    This report describes intensive Monte Carlo simulations carried out to be compared with the results of the first run cycle with DANCE (Detector for Advanced Neutron Capture Experiments). The experimental results were gained during the commissioning phase 2002/2003 with only a part of the array. Based on the results of these simulations the most important items to be improved before the next experiments will be addressed.

  8. A Comparison of Theory and Experiment for High-speed Free-molecule Flow

    NASA Technical Reports Server (NTRS)

    Stalder, Jackson R; Goodwin, Glen; Creager, Marcus O

    1951-01-01

    A comparison is made of free-molecule-flow theory with the results of wind-tunnel tests performed to determine the drag and temperature-rise characteristics of a transverse circular cylinder. The measured values of the cylinder center-point temperature confirmed the salient point of the heat-transfer analysis which was the prediction that an insulated cylinder would attain a temperature higher than the stagnation temperature of the stream. Good agreement was obtained between the theoretical and the experimental values for the drag coefficient.

  9. Oscillation and extinction thresholds of the clarinet: comparison of analytical results and experiments.

    PubMed

    Dalmont, Jean-Pierre; Frappé, Cyrille

    2007-08-01

    In the context of a simplified model of the clarinet in which the losses are assumed to be frequency independent the analytic expressions of the various thresholds have been calculated in a previous paper [Dalmont et al., J. Acoust. Soc. Am. 118, 32.94-3305 (2005)]. The present work is a quantitative comparison between "theoretical" values of the thresholds and their experimental values measured by using an artificial mouth. It is shown that the "Raman" model, providing that nonlinear losses are taken into account, is reliable and able to predict the values of thresholds.

  10. Comparison of an unsaturated soil zone model (SESOIL) predictions with a laboratory leaching experiment

    SciTech Connect

    Hetrick, D.M.; Travis, C.C.; Kinerson, R.S.

    1988-01-01

    Model predictions of a modified version of the soil compartment model SESOIL are compared with laboratory measurements of pollutant transport in soil. A brief description of SESOIL is given and modifications that have been made to the model are summarized. Comparisons are performed using data from a laboratory soil column study involving six chemicals (dicamba, 2,4-dichlorophenoxyacetic acid, atrazine, diazinon, pentachlorophenol, and lindane). Overall, SESOIL model predictions are in good agreement with the empirical data. Limitation of the model are discussed. 15 refs., 2 figs., 3 tabs.

  11. Catalytic honeycomb combustor - Steady-state model and comparison with experiment

    NASA Technical Reports Server (NTRS)

    Tien, J. S.

    1980-01-01

    A steady-state lean combustion model for monolithic catalytic combustors is given. The model, consisting of several semi-global chemical reaction steps in the gas-phase and on the surface, is capable of analyzing CO and THC emissions. In the model computation presented, the influence of operating and design parameters on the minimum combustor length is studied. Special attention is given to the effect of after-bed gas-phase reaction space. Comparison with experimental data indicates good agreement in the range of parameters covered.

  12. Comparison of Resource Requirements for a Wind Tunnel Test Designed with Conventional vs. Modern Design of Experiments Methods

    NASA Technical Reports Server (NTRS)

    DeLoach, Richard; Micol, John R.

    2011-01-01

    The factors that determine data volume requirements in a typical wind tunnel test are identified. It is suggested that productivity in wind tunnel testing can be enhanced by managing the inference error risk associated with evaluating residuals in a response surface modeling experiment. The relationship between minimum data volume requirements and the factors upon which they depend is described and certain simplifications to this relationship are realized when specific model adequacy criteria are adopted. The question of response model residual evaluation is treated and certain practical aspects of response surface modeling are considered, including inference subspace truncation. A wind tunnel test plan developed by using the Modern Design of Experiments illustrates the advantages of an early estimate of data volume requirements. Comparisons are made with a representative One Factor At a Time (OFAT) wind tunnel test matrix developed to evaluate a surface to air missile.

  13. Mothers with intellectual disability, their experiences of maltreatment, and their children's attachment representations: a small-group matched comparison study.

    PubMed

    Granqvist, Pehr; Forslund, Tommie; Fransson, Mari; Springer, Lydia; Lindberg, Lene

    2014-01-01

    Maternal intellectual disability (ID) is regarded a risk factor in child development, but there is no scientific evidence on maternal ID in relation to children's attachment. Using a matched comparison design, a small group (n = 23) of mothers diagnosed with ID was studied to help fill this gap. Besides maternal ID, we examined the role of abuse/trauma/maltreatment (ATM) in the mothers' biographies, along with potential confounds. Comparison group mothers (n = 25) had normal variations in intelligence and matched mothers with ID on residential area, income, child age, and sex. History of maternal ATM was assessed using a semi-structured interview and was found to be significantly more likely in the ID group mothers' experience than the comparison group mothers. Children's (M age = 77 months) attachment representations were assessed with the Separation Anxiety Test. Among children of mothers with ID, a substantial minority (35%) had a secure and the vast majority (>80%) an organized attachment representation. Mothers with ID who had suffered elevated ATM were significantly more likely to have children who were scored high on disorganization and insecurity. We discuss possible implications of our findings for societal considerations regarding parenting and child attachment in the context of parental ID status. PMID:24931835

  14. Mothers with intellectual disability, their experiences of maltreatment, and their children's attachment representations: a small-group matched comparison study.

    PubMed

    Granqvist, Pehr; Forslund, Tommie; Fransson, Mari; Springer, Lydia; Lindberg, Lene

    2014-01-01

    Maternal intellectual disability (ID) is regarded a risk factor in child development, but there is no scientific evidence on maternal ID in relation to children's attachment. Using a matched comparison design, a small group (n = 23) of mothers diagnosed with ID was studied to help fill this gap. Besides maternal ID, we examined the role of abuse/trauma/maltreatment (ATM) in the mothers' biographies, along with potential confounds. Comparison group mothers (n = 25) had normal variations in intelligence and matched mothers with ID on residential area, income, child age, and sex. History of maternal ATM was assessed using a semi-structured interview and was found to be significantly more likely in the ID group mothers' experience than the comparison group mothers. Children's (M age = 77 months) attachment representations were assessed with the Separation Anxiety Test. Among children of mothers with ID, a substantial minority (35%) had a secure and the vast majority (>80%) an organized attachment representation. Mothers with ID who had suffered elevated ATM were significantly more likely to have children who were scored high on disorganization and insecurity. We discuss possible implications of our findings for societal considerations regarding parenting and child attachment in the context of parental ID status.

  15. Multi-scale gyrokinetic simulations: Comparison with experiment and implications for predicting turbulence and transport

    NASA Astrophysics Data System (ADS)

    Howard, N. T.; Holland, C.; White, A. E.; Greenwald, M.; Candy, J.; Creely, A. J.

    2016-05-01

    To better understand the role of cross-scale coupling in experimental conditions, a series of multi-scale gyrokinetic simulations were performed on Alcator C-Mod, L-mode plasmas. These simulations, performed using all experimental inputs and realistic ion to electron mass ratio ((mi/me)1/2 = 60.0), simultaneously capture turbulence at the ion ( kθρs˜O (1.0 ) ) and electron-scales ( kθρe˜O (1.0 ) ). Direct comparison with experimental heat fluxes and electron profile stiffness indicates that Electron Temperature Gradient (ETG) streamers and strong cross-scale turbulence coupling likely exist in both of the experimental conditions studied. The coupling between ion and electron-scales exists in the form of energy cascades, modification of zonal flow dynamics, and the effective shearing of ETG turbulence by long wavelength, Ion Temperature Gradient (ITG) turbulence. The tightly coupled nature of ITG and ETG turbulence in these realistic plasma conditions is shown to have significant implications for the interpretation of experimental transport and fluctuations. Initial attempts are made to develop a "rule of thumb" based on linear physics, to help predict when cross-scale coupling plays an important role and to inform future modeling of experimental discharges. The details of the simulations, comparisons with experimental measurements, and implications for both modeling and experimental interpretation are discussed.

  16. Comparison of mean radiant temperature from field experiment and modelling: a case study in Freiburg, Germany

    NASA Astrophysics Data System (ADS)

    Chen, Yung-Chang; Lin, Tzu-Ping; Matzarakis, Andreas

    2014-11-01

    Mean radiant temperature ( T mrt) based on two measurement methods and outputs from three models are compared in this study. They are the six direction radiation method, globe thermometer method, RayMan model, ENVI-met model and SOLWEIG model. The comparison shows that globe thermometer method may overestimate the T mrt since wind velocity is a key variable in the estimation based on this method. For better estimation, T mrt measured by the globe-thermometer method be corrected by the imported wind speed (stable, low and assuming wind speed) and validated by the six-direction radiation method. The comparison of models shows that the RayMan model's evaluation of T mrt involving global radiation with fine time resolution was better than the corresponding evaluations under the other two models (ENVI-met and SOLWEIG) in this case. However, the RayMan model can only assess T mrt for a one-point one-time context, whereas the other two models can evaluate two-dimensional T mrt. For two-dimensional evaluations of T mrt, SOLWEIG have a better prediction of T mrt than ENVI-met, and ENVI-met can simulate several different variables, which are wind field, particle distribution, CO2 distribution and the other thermal parameters ( T a, surface temperature and radiation fluxes), that SOLWEIG cannot.

  17. Direct Numerical Simulation of Fracture Behaviour for Random Short Wood Fibres Reinforced Composites, Comparison with Digital Image Correlation Experiments

    NASA Astrophysics Data System (ADS)

    Shen, M.; Touchard, F.; Bezine, G.; Brillaud, J.

    2010-06-01

    The work is to predict fracture behaviour of bio-composites from the tensile properties of its components. In this work, we have realized a direct numerical simulation of fracture behaviour for random short spruce fibers reinforced composites. For calculations, wood fibers have been considered as linear elastic bodies, polypropylene matrix as an elastic-plastic material. Then, numerical results have been compared with experimental results that have been obtained by digital image correlation. This comparison indicates that random fiber FE model of random short spruce fibers reinforced composites can be able to fairly reflect the influence of random fibers microstructure in the composite on its fracture behavior. The calculation of both random fiber and homogeneous FE model and their comparison with experiments show that the average values of J-integral in a region in the front of the crack tip from both numerical FE models are in good agreement with the average J value of DIC experiment in the same region when the numerical and experimental CT specimens of the short spruce fiber reinforced composite are subjected to the same extension at their loading point.

  18. Is it really so bad? A comparison of positive and negative experiences in Antarctic winter stations

    NASA Technical Reports Server (NTRS)

    Wood, J.; Hysong, S. J.; Lugg, D. J.; Harm, D. L.

    2000-01-01

    This study examined the range of positive and negative themes reported by 104 Australian Antarctic winter personnel at four stations during two austral winters. Reports from the expeditioners were subjected to a content analysis using the TextSmart software from SPSS, Inc. Results indicated that, although the list of negative experiences is lengthy, most events are relatively rare. On the other hand, although the list of positive experiences is short, the frequencies with which they are reported are much greater than for most of the problems. Possible explanations for these themes and for future directions are discussed.

  19. Is it really so bad? A comparison of positive and negative experiences in Antarctic winter stations.

    PubMed

    Wood, J; Hysong, S J; Lugg, D J; Harm, D L

    2000-01-01

    This study examined the range of positive and negative themes reported by 104 Australian Antarctic winter personnel at four stations during two austral winters. Reports from the expeditioners were subjected to a content analysis using the TextSmart software from SPSS, Inc. Results indicated that, although the list of negative experiences is lengthy, most events are relatively rare. On the other hand, although the list of positive experiences is short, the frequencies with which they are reported are much greater than for most of the problems. Possible explanations for these themes and for future directions are discussed.

  20. A Comparison Between Girls' and Boys' Experiences of Unwanted Sexual Behaviour in Secondary Schools

    ERIC Educational Resources Information Center

    Timmerman, Greetje

    2005-01-01

    Background: This study examines gender differences (and similarities) in the context, meaning and effects of unwanted sexual behaviour in secondary schools. Purpose First, the study's purpose is exploration of variables that discriminate between girls' and boys' experiences of unwanted sexual behaviour. Secondly, the aim is to find empirical…

  1. A COMPARISON OF PARTICLE MASS SPECTROMETERS DURING THE 1999 ATLANTA SUPERSITES EXPERIMENT

    EPA Science Inventory

    During the Atlanta SuperSite Experiment, four particle mass spectrometers were operated together for the first time: NOAA's PALMS (Particle Analysis by Laser Mass Spectrometry), U. C. Riverside's ATOFMS (Aerosol Time-of-Flight Mass Spectrometry), U. Delaware's RSMS-II (Rapid Si...

  2. Field Experience Supervision: A Comparison of Cooperating Teachers' and College Supervisors' Evaluations of Student Teachers

    ERIC Educational Resources Information Center

    Hunn, Lorie L.

    2009-01-01

    This study explored and compared the ways in which school-based cooperating teachers and college supervisors evaluate student teachers. The scores allocated to student teachers by school-based cooperating teachers and college supervisors in the final field experience evaluations of student teachers were analyzed. A mixed methods research design…

  3. Statistical comparison between experiments and numerical simulations of shock-accelerated gas cylinders

    SciTech Connect

    Rider, William; Kamm, J. R.; Zoldi, C. A.; Tomkins, C. D.

    2002-01-01

    We present detailed spatial analysis comparing experimental data and numerical simulation results for Richtmyer-Meshkov instability experiments of Prestridge et al. and Tomkins et al. These experiments consist, respectively, of one and two diffuse cylinders of sulphur hexafluoride (SF{sub 6}) impulsively accelerated by a Mach 1.2 shockwave in air. The subsequent fluid evolution and mixing is driven by the deposition of baroclinic vorticity at the interface between the two fluids. Numerical simulations of these experiments are performed with three different versions of high resolution finite volume Godunov methods, including a new weighted adaptive Runge-Kutta (WARK) scheme. We quantify the nature of the mixing using using integral measures as well as fractal analysis and continuous wavelet transforms. Our investigation of the gas cylinder configurations follows the path of our earlier studies of the geometrically and dynamically more complex gas 'curtain' experiment. In those studies, we found significant discrepancies in the details of the experimentally measured mixing and the details of the numerical simulations. Here we evaluate the effects of these hydrodynamic integration techniques on the diffuse gas cylinder simulations, which we quantitatively compare with experimental data.

  4. Shock timing experiments on the National Ignition Facility: Initial results and comparison with simulation

    NASA Astrophysics Data System (ADS)

    Robey, H. F.; Boehly, T. R.; Celliers, P. M.; Eggert, J. H.; Hicks, D.; Smith, R. F.; Collins, R.; Bowers, M. W.; Krauter, K. G.; Datte, P. S.; Munro, D. H.; Milovich, J. L.; Jones, O. S.; Michel, P. A.; Thomas, C. A.; Olson, R. E.; Pollaine, S.; Town, R. P. J.; Haan, S.; Callahan, D.; Clark, D.; Edwards, J.; Kline, J. L.; Dixit, S.; Schneider, M. B.; Dewald, E. L.; Widmann, K.; Moody, J. D.; Döppner, T.; Radousky, H. B.; Throop, A.; Kalantar, D.; DiNicola, P.; Nikroo, A.; Kroll, J. J.; Hamza, A. V.; Horner, J. B.; Bhandarkar, S. D.; Dzenitis, E.; Alger, E.; Giraldez, E.; Castro, C.; Moreno, K.; Haynam, C.; LaFortune, K. N.; Widmayer, C.; Shaw, M.; Jancaitis, K.; Parham, T.; Holunga, D. M.; Walters, C. F.; Haid, B.; Mapoles, E. R.; Sater, J.; Gibson, C. R.; Malsbury, T.; Fair, J.; Trummer, D.; Coffee, K. R.; Burr, B.; Berzins, L. V.; Choate, C.; Brereton, S. J.; Azevedo, S.; Chandrasekaran, H.; Eder, D. C.; Masters, N. D.; Fisher, A. C.; Sterne, P. A.; Young, B. K.; Landen, O. L.; Van Wonterghem, B. M.; MacGowan, B. J.; Atherton, J.; Lindl, J. D.; Meyerhofer, D. D.; Moses, E.

    2012-04-01

    Capsule implosions on the National Ignition Facility (NIF) [Lindl et al., Phys. Plasmas 11, 339 (2004)] are underway with the goal of compressing deuterium-tritium (DT) fuel to a sufficiently high areal density (ρR) to sustain a self-propagating burn wave required for fusion power gain greater than unity. These implosions are driven with a carefully tailored sequence of four shock waves that must be timed to very high precision in order to keep the DT fuel on a low adiabat. Initial experiments to measure the strength and relative timing of these shocks have been conducted on NIF in a specially designed surrogate target platform known as the keyhole target. This target geometry and the associated diagnostics are described in detail. The initial data are presented and compared with numerical simulations. As the primary goal of these experiments is to assess and minimize the adiabat in related DT implosions, a methodology is described for quantifying the adiabat from the shock velocity measurements. Results are contrasted between early experiments that exhibited very poor shock timing and subsequent experiments where a modified target geometry demonstrated significant improvement.

  5. A Comparison of Methods to Test for Mediation in Multisite Experiments

    ERIC Educational Resources Information Center

    Pituch, Keenan A.; Whittaker, Tiffany A.; Stapleton, Laura M.

    2005-01-01

    A Monte Carlo study extended the research of MacKinnon, Lockwood, Hoffman, West, and Sheets (2002) for single-level designs by examining the statistical performance of four methods to test for mediation in a multilevel experimental design. The design studied was a two-group experiment that was replicated across several sites, included a single…

  6. Comparison of Web and Mail Surveys in Collecting Illicit Drug Use Data: A Randomized Experiment

    ERIC Educational Resources Information Center

    McCabe, Sean Esteban

    2004-01-01

    This randomized experiment examined survey mode effects for self-reporting illicit drug use by comparing prevalence estimates between a Web-based survey and a mail-based survey. A random sample of 7,000 traditional-aged undergraduate students attending a large public university in the United States was selected to participate in the spring of…

  7. Study Abroad Survey Instruments: A Comparison of Survey Types and Experiences

    ERIC Educational Resources Information Center

    Durrant, Marie Bradshaw; Dorius, Cassandra Rasmussen

    2007-01-01

    This study examines different survey instruments used to assess the experiences of U.S. study abroad participants. The intended audience is international and area study practitioners interested in assessing study abroad programs through postprogram interviews. An interview with the top 20 universities for number of students sent on study abroad…

  8. A Comparison of Ionic and Covalent Iodine Dihalides: An Integrated Experiment.

    ERIC Educational Resources Information Center

    Woolf, Alfred A.

    1978-01-01

    Compares the preparation and decomposition of potassium dibromoiodate and of phenyl iodine dichloride in a flexible experiment which accustoms the student to handle halogens, to test for halogens in mixtures, and to appreciate the difference between thermodynamic and kinetic control of reactions. (Author/MA)

  9. Chinese Students' Science-Related Experiences: Comparison of the ROSE Study in Xinjiang and Shanghai

    ERIC Educational Resources Information Center

    Yeung, Yau-yuen; Li, Yufeng

    2015-01-01

    Background: Students' daily-life experiences may render favorable effects on the students' affective domain like interest, enthusiasm, motivation, joy, curiosity, awareness, and eagerness to learn science as not commonly found in the classroom environment. However, no rigorous research has been reported on those aspects in Mainland China despite…

  10. A Comparison of the Internship Experience for Student Interns Placed in Different Urban School Environments

    ERIC Educational Resources Information Center

    McKinney, Sueanne E.; Finke, Janet A.

    2005-01-01

    The purpose of this investigation was to determine if there was a difference in the internship experience between student interns placed in either an urban Professional Development School or an urban non-Professional Development School. Student interns from two urban universities who have partnerships with neighboring urban school districts…

  11. Receiving the Initial Down Syndrome Diagnosis: A Comparison of Prenatal and Postnatal Parent Group Experiences

    ERIC Educational Resources Information Center

    Nelson Goff, Briana S.; Springer, Nicole; Foote, Laura Cline; Frantz, Courtney; Peak, Madison; Tracy, Courtney; Veh, Taylor; Bentley, Gail E.; Cross, Kayli A.

    2013-01-01

    This study explored the preliminary experiences of parents upon learning of their child's diagnosis of Down syndrome. Qualitative data from a web-based, national survey were analyzed based on two groups: prenatal ("n" = 46) or postnatal ("n" = 115) diagnosis. Three primary categories emerged from the data analysis:…

  12. Early Learning Experience and Adolescent Anxiety: A Cross-Cultural Comparison between Japan and England

    ERIC Educational Resources Information Center

    Essau, Cecilia A.; Ishikawa, Shin-ichi; Sasagawa, Satoko

    2011-01-01

    The main aim of this study was to compare the frequency of anxiety symptoms among adolescents in Japan and England, and to examine the association between early learning experiences and anxiety symptoms. A total of 299 adolescents (147 from England and 152 from Japan), aged 12 to 17 years were investigated. Results showed that adolescents in…

  13. A Comparison of the Abuse Experiences of Male and Female Adults Molested as Children.

    ERIC Educational Resources Information Center

    Kendall-Tackett, Kathleen A.; Simon, Arthur F.

    To determine whether the molestation experiences of boys and girls differ, this study analyzed data from 365 adults (40 male and 325 female) molested as children, and compared findings for males and females on the identity of the perpetrator, age at onset and end of molestation, duration of molestation, type of sexual acts, and whether the…

  14. Preservice Teachers' Reflection on Clinical Experiences: A Comparison of Blog and Final Paper Assignments

    ERIC Educational Resources Information Center

    Harland, Darci J.; Wondra, Joshua D.

    2011-01-01

    This study focused on the depth of reflection in the writing of preservice teachers who completed end-of-the-semester reflective papers or reflective blogs for undergraduate education courses associated with clinical experiences. Coders rated the depth of reflection as one of four categories: non-reflection, understanding, reflection, or critical…

  15. Career Decisions and Experiences of Social Work Faculty: A Gender Comparison

    ERIC Educational Resources Information Center

    Holley, Lynn C.; Young, Diane S.

    2005-01-01

    This study uses quantitative and qualitative findings from a mail and online questionnaire to examine the experiences and perspectives of 76 doctoral-degreed social work faculty about the factors that affected their career decisions. The authors discuss similarities and differences between women and men in job-related decision making. Respondent…

  16. Casimir interaction at liquid nitrogen temperature: Comparison between experiment and theory

    NASA Astrophysics Data System (ADS)

    Castillo-Garza, R.; Xu, J.; Klimchitskaya, G. L.; Mostepanenko, V. M.; Mohideen, U.

    2013-08-01

    We have measured the normalized gradient of the Casimir force between Au-coated surfaces of the sphere and the plate and equivalent Casimir pressure between two parallel Au plates at T=77K. These measurements have been performed by means of dynamic force microscope adapted for operating at low temperatures in the frequency shift technique. It was shown that the measurement results at T=77K are in a very good agreement with those at T=300K and with computations at T=77K using both theoretical approaches to the thermal Casimir force proposed in the literature. No thermal effect in the Casimir pressure was observed in the limit of experimental errors with the increase of temperature from T=77 to 300K. Taking this into account, we have discussed the possible role of patch potentials in the comparison between measured and calculated Casimir pressures.

  17. The drag of airplane radiators with special reference to air heating : comparison of theory and experiment

    NASA Technical Reports Server (NTRS)

    Gothert, B

    1939-01-01

    This report contains a survey of past radiator research. This report also is intended as a systematic comparison of theoretical and experimental radiator drag, with the object of ascertaining the most important loss sources and their interaction in different cases of installation, and to separate the radiator systems which are amenable to calculation, both as regards axial flow and drag. The sources of loss due to the diffuser are to be looked into closely as in many cases they can be of preeminent magnitude and their customary appraisal, according to Fliegner's formula, does not meet actual conditions. Besides, generally applicable equations and charts are developed for the rapid determination of the heating effect of radiators as regards flow and drag, and then checked by routine tests on hot radiators.

  18. Comparison of seismic and hydrodynamic yield determinations for the Soviet joint verification experiment of 1988.

    PubMed

    Sykes, L R; Ekström, G

    1989-05-01

    Seismic magnitudes determined from surface and body waves for the Soviet underground nuclear explosion of September 14, 1988, are used to calculate the yield of that event from previously derived calibration curves. The yield obtained by combining the two seismic estimates is 113 kilotons, which is very close to those obtained by hydrodynamic measurements made on-site. This comparison substantiates previous conclusions about the sizes of past Soviet weapons tests and compliance with the Threshold Test Ban Treaty. The factor of uncertainty in the combined seismic yield is 1.28 at the 68% and 1.62 at the 95% confidence levels, demonstrating that accuracies considerably better than a factor of 2 can be obtained by combining seismic determinations of yield.

  19. Comprehensive fracture diagnostics experiment. Part II. Comparison of seven fracture azimuth measurements

    SciTech Connect

    Smith, M.B.; Ren, N.K.; Sorrells, G.G.; Teufel, L.W.

    1985-01-01

    A great deal of effort has been devoted recently to find geophysical techniques for measuring the hydraulic fracture azimuth. This paper discusses a comparison of seven different measurements used to determine the azimuth in a sandstone formation at a depth of 1000 ft (320 m). The azimuth was determined as N95E, but significant differences existed between some of the results. This is of fundamental importance since in developing new measurements, the limits of these must be found and honored. Of particular interest are the results from microseismic monitoring. The lack of results suggests that remote (e.g., surface) monitoring for seismic events may be impractical for normal, sedimentary, hydrocarbon-bearing formations. 33 refs., 6 figs., 3 tabs.

  20. A comparison of experiment and theory for sound propagation in variable area ducts

    NASA Technical Reports Server (NTRS)

    Nayfeh, A. H.; Kaiser, J. E.; Marshall, R. L.; Hurst, C. J.

    1980-01-01

    An experimental and analytical program has been carried out to evaluate sound suppression techniques in ducts that produce refraction effects due to axial velocity gradients. The analytical program employs a computer code based on the method of multiple scales to calculate the influence of axial variations due to slow changes in the cross-sectional area as well as transverse gradients due to the wall boundary layers. Detailed comparisons between the analytical predictions and the experimental measurements have been made. The circumferential variations of pressure amplitudes and phases at several axial positions have been examined in straight and variable area ducts, with hard walls and lined sections, and with and without a mean flow. Reasonable agreement between the theoretical and experimental results has been found.

  1. Comparison of Monte Carlo simulations of cytochrome b6f with experiment using Latin hypercube sampling.

    PubMed

    Schumaker, Mark F; Kramer, David M

    2011-09-01

    We have programmed a Monte Carlo simulation of the Q-cycle model of electron transport in cytochrome b(6)f complex, an enzyme in the photosynthetic pathway that converts sunlight into biologically useful forms of chemical energy. Results were compared with published experiments of Kramer and Crofts (Biochim. Biophys. Acta 1183:72-84, 1993). Rates for the simulation were optimized by constructing large numbers of parameter sets using Latin hypercube sampling and selecting those that gave the minimum mean square deviation from experiment. Multiple copies of the simulation program were run in parallel on a Beowulf cluster. We found that Latin hypercube sampling works well as a method for approximately optimizing very noisy objective functions of 15 or 22 variables. Further, the simplified Q-cycle model can reproduce experimental results in the presence or absence of a quinone reductase (Q(i)) site inhibitor without invoking ad hoc side-reactions.

  2. Comprehensive comparisons of geodesic acoustic mode characteristics and dynamics between Tore Supra experiments and gyrokinetic simulations

    NASA Astrophysics Data System (ADS)

    Storelli, A.; Vermare, L.; Hennequin, P.; Gürcan, Ö. D.; Dif-Pradalier, G.; Sarazin, Y.; Garbet, X.; Görler, T.; Singh, Rameswar; Morel, P.; Grandgirard, V.; Ghendrih, P.

    2015-06-01

    In a dedicated collisionality scan in Tore Supra, the geodesic acoustic mode (GAM) is detected and identified with the Doppler backscattering technique. Observations are compared to the results of a simulation with the gyrokinetic code GYSELA. We found that the GAM frequency in experiments is lower than predicted by simulation and theory. Moreover, the disagreement is higher in the low collisionality scenario. Bursts of non harmonic GAM oscillations have been characterized with filtering techniques, such as the Hilbert-Huang transform. When comparing this dynamical behaviour between experiments and simulation, the probability density function of GAM amplitude and the burst autocorrelation time are found to be remarkably similar. In the simulation, where the radial profile of GAM frequency is continuous, we observed a phenomenon of radial phase mixing of the GAM oscillations, which could influence the burst autocorrelation time.

  3. Mixing of a point-source indoor pollutant: Numerical predictions and comparison with experiments

    SciTech Connect

    Lobscheid, C.; Gadgil, A.J.

    2002-01-01

    In most practical estimates of indoor pollutant exposures, it is common to assume that the pollutant is uniformly and instantaneously mixed in the indoor space. It is also commonly known that this assumption is simplistic, particularly for point sources, and for short-term or localized indoor exposures. We report computational fluid dynamics (CFD) predictions of mixing time of a point-pulse release of a pollutant in an unventilated mechanically mixed isothermal room. We aimed to determine the adequacy of the standard RANS two-equation ({kappa}-{var_epsilon}) turbulence model to predict the mixing times under these conditions. The predictions were made for the twelve mixing time experiments performed by Drescher et al. (1995). We paid attention to adequate grid resolution, suppression of numerical diffusion, and careful simulation of the mechanical blowers used in the experiments. We found that the predictions are in good agreement with experimental measurements.

  4. Comprehensive comparisons of geodesic acoustic mode characteristics and dynamics between Tore Supra experiments and gyrokinetic simulations

    SciTech Connect

    Storelli, A. Vermare, L.; Hennequin, P.; Gürcan, Ö. D.; Singh, Rameswar; Morel, P.; Dif-Pradalier, G.; Sarazin, Y.; Garbet, X.; Grandgirard, V.; Ghendrih, P.; Görler, T.

    2015-06-15

    In a dedicated collisionality scan in Tore Supra, the geodesic acoustic mode (GAM) is detected and identified with the Doppler backscattering technique. Observations are compared to the results of a simulation with the gyrokinetic code GYSELA. We found that the GAM frequency in experiments is lower than predicted by simulation and theory. Moreover, the disagreement is higher in the low collisionality scenario. Bursts of non harmonic GAM oscillations have been characterized with filtering techniques, such as the Hilbert-Huang transform. When comparing this dynamical behaviour between experiments and simulation, the probability density function of GAM amplitude and the burst autocorrelation time are found to be remarkably similar. In the simulation, where the radial profile of GAM frequency is continuous, we observed a phenomenon of radial phase mixing of the GAM oscillations, which could influence the burst autocorrelation time.

  5. Comparison of Monte Carlo simulations of cytochrome b6f with experiment using Latin hypercube sampling.

    PubMed

    Schumaker, Mark F; Kramer, David M

    2011-09-01

    We have programmed a Monte Carlo simulation of the Q-cycle model of electron transport in cytochrome b(6)f complex, an enzyme in the photosynthetic pathway that converts sunlight into biologically useful forms of chemical energy. Results were compared with published experiments of Kramer and Crofts (Biochim. Biophys. Acta 1183:72-84, 1993). Rates for the simulation were optimized by constructing large numbers of parameter sets using Latin hypercube sampling and selecting those that gave the minimum mean square deviation from experiment. Multiple copies of the simulation program were run in parallel on a Beowulf cluster. We found that Latin hypercube sampling works well as a method for approximately optimizing very noisy objective functions of 15 or 22 variables. Further, the simplified Q-cycle model can reproduce experimental results in the presence or absence of a quinone reductase (Q(i)) site inhibitor without invoking ad hoc side-reactions. PMID:21221830

  6. A comparison of older adults' subjective experience with virtual and real environments during dynamic balance activities

    PubMed Central

    Proffitt, Rachel; Lange, Belinda; Chen, Christina; Winstein, Carolee

    2014-01-01

    The purpose of this study was to explore the subjective experience of older adults interacting with both virtual and real environments. Thirty healthy older adults engaged with real and virtual tasks of similar motor demands: reaching to a target in standing and stepping stance. Immersive tendencies and absorption scales were administered before the session. Game engagement and experience questionnaires were completed after each task, followed by a semi-structured interview at the end of the testing session. Data were analyzed respectively using paired t-tests and grounded theory methodology. Participants preferred the virtual task over the real task. They also reported an increase in presence and absorption with the virtual task, describing an external focus of attention. Findings will be used to inform future development of appropriate game-based balance training applications that could be embedded in the home or community settings as part of evidence-based fall prevention programs. PMID:24334299

  7. A global ab initio potential for HCN/HNC, exact vibrational energies, and comparison to experiment

    NASA Technical Reports Server (NTRS)

    Bentley, Joseph A.; Bowman, Joel M.; Gazdy, Bela; Lee, Timothy J.; Dateo, Christopher E.

    1992-01-01

    An ab initio (i.e., from first principles) calculation of vibrational energies of HCN and HNC is reported. The vibrational calculations were done with a new potential derived from a fit to 1124 ab initio electronic energies which were calculated using the highly accurate CCSD(T) coupled-cluster method in conjunction with a large atomic natural orbital basis set. The properties of this potential are presented, and the vibrational calculations are compared to experiment for 54 vibrational transitions, 39 of which are for zero total angular momentum, J = 0, and 15 of which are for J = 1. The level of agreement with experiment is unprecedented for a triatomic with two nonhydrogen atoms, and demonstrates the capability of the latest computational methods to give reliable predictions on a strongly bound triatomic molecule at very high levels of vibrational excitation.

  8. Direct comparison of elastic incoherent neutron scattering experiments with molecular dynamics simulations of DMPC phase transitions.

    PubMed

    Aoun, Bachir; Pellegrini, Eric; Trapp, Marcus; Natali, Francesca; Cantù, Laura; Brocca, Paola; Gerelli, Yuri; Demé, Bruno; Marek Koza, Michael; Johnson, Mark; Peters, Judith

    2016-04-01

    Neutron scattering techniques have been employed to investigate 1,2-dimyristoyl-sn -glycero-3-phosphocholine (DMPC) membranes in the form of multilamellar vesicles (MLVs) and deposited, stacked multilamellar-bilayers (MLBs), covering transitions from the gel to the liquid phase. Neutron diffraction was used to characterise the samples in terms of transition temperatures, whereas elastic incoherent neutron scattering (EINS) demonstrates that the dynamics on the sub-macromolecular length-scale and pico- to nano-second time-scale are correlated with the structural transitions through a discontinuity in the observed elastic intensities and the derived mean square displacements. Molecular dynamics simulations have been performed in parallel focussing on the length-, time- and temperature-scales of the neutron experiments. They correctly reproduce the structural features of the main gel-liquid phase transition. Particular emphasis is placed on the dynamical amplitudes derived from experiment and simulations. Two methods are used to analyse the experimental data and mean square displacements. They agree within a factor of 2 irrespective of the probed time-scale, i.e. the instrument utilized. Mean square displacements computed from simulations show a comparable level of agreement with the experimental values, albeit, the best match with the two methods varies for the two instruments. Consequently, experiments and simulations together give a consistent picture of the structural and dynamical aspects of the main lipid transition and provide a basis for future, theoretical modelling of dynamics and phase behaviour in membranes. The need for more detailed analytical models is pointed out by the remaining variation of the dynamical amplitudes derived in two different ways from experiments on the one hand and simulations on the other. PMID:27112937

  9. Isentropic Compression for TATB Based HE Samples, Numerical Simulations and Comparison with Experiments

    SciTech Connect

    Lefrancois, A; Vandersall, K; L'Eplattenier, P; Burger, M

    2006-02-06

    Isentropic compression experiments and numerical simulations on TATB based HE were performed respectively at Z accelerator facility from Sandia National Laboratory and at Lawrence Livermore National Laboratory in order to study the isentrope and associated Hugoniot of this HE [1]. 3D configurations have been calculated here to test the new beta version of the electromagnetism package coupled with the dynamics in Ls-Dyna and compared with the ICE Z shot 1967.

  10. Critical transition for the edge shear layer formation: Comparison of model and experiment

    SciTech Connect

    Carreras, B. A.; Garcia, L.; Pedrosa, M. A.; Hidalgo, C.

    2006-12-15

    The experimental results for the emergence of the plasma edge shear flow layer in TJ-II [C. Alehaldre et al.Fusion Technol. 17, 131 (1990)] can be explained using a simple model for a second-order transition based on the sheared flow amplification by Reynolds stress and turbulence suppression by shearing. In the dynamics of the model, the resistive interchange instability is used. This model gives power dependence on density gradients before and after the transition, consistent with experiment.

  11. Direct comparison of elastic incoherent neutron scattering experiments with molecular dynamics simulations of DMPC phase transitions.

    PubMed

    Aoun, Bachir; Pellegrini, Eric; Trapp, Marcus; Natali, Francesca; Cantù, Laura; Brocca, Paola; Gerelli, Yuri; Demé, Bruno; Marek Koza, Michael; Johnson, Mark; Peters, Judith

    2016-04-01

    Neutron scattering techniques have been employed to investigate 1,2-dimyristoyl-sn -glycero-3-phosphocholine (DMPC) membranes in the form of multilamellar vesicles (MLVs) and deposited, stacked multilamellar-bilayers (MLBs), covering transitions from the gel to the liquid phase. Neutron diffraction was used to characterise the samples in terms of transition temperatures, whereas elastic incoherent neutron scattering (EINS) demonstrates that the dynamics on the sub-macromolecular length-scale and pico- to nano-second time-scale are correlated with the structural transitions through a discontinuity in the observed elastic intensities and the derived mean square displacements. Molecular dynamics simulations have been performed in parallel focussing on the length-, time- and temperature-scales of the neutron experiments. They correctly reproduce the structural features of the main gel-liquid phase transition. Particular emphasis is placed on the dynamical amplitudes derived from experiment and simulations. Two methods are used to analyse the experimental data and mean square displacements. They agree within a factor of 2 irrespective of the probed time-scale, i.e. the instrument utilized. Mean square displacements computed from simulations show a comparable level of agreement with the experimental values, albeit, the best match with the two methods varies for the two instruments. Consequently, experiments and simulations together give a consistent picture of the structural and dynamical aspects of the main lipid transition and provide a basis for future, theoretical modelling of dynamics and phase behaviour in membranes. The need for more detailed analytical models is pointed out by the remaining variation of the dynamical amplitudes derived in two different ways from experiments on the one hand and simulations on the other.

  12. Comparison of hydrodynamic simulations with two-shockwave drive target experiments

    NASA Astrophysics Data System (ADS)

    Karkhanis, Varad; Ramaprabhu, Praveen; Buttler, William

    2015-11-01

    We consider hydrodynamic continuum simulations to mimic ejecta generation in two-shockwave target experiments, where metallic surface is loaded by two successive shock waves. Time of second shock in simulations is determined to match experimental amplitudes at the arrival of the second shock. The negative Atwood number (A --> - 1) of ejecta simulations leads to two successive phase inversions of the interface corresponding to the passage of the shocks from heavy to light media in each instance. Metallic phase of ejecta (solid/liquid) depends on shock loading pressure in the experiment, and we find that hydrodynamic simulations quantify the liquid phase ejecta physics with a fair degree of accuracy, where RM instability is not suppressed by the strength effect. In particular, we find that our results of free surface velocity, maximum ejecta velocity, and maximum ejecta areal density are in excellent agreement with their experimental counterparts, as well as ejecta models. We also comment on the parametric space for hydrodynamic simulations in which they can be used to compare with the target experiments.

  13. Comparison of hydrodynamic simulations with two-shockwave drive target experiments

    NASA Astrophysics Data System (ADS)

    Karkhanis, Varad; Ramaprabhu, Praveen; Buttler, William

    2015-11-01

    We consider hydrodynamic continuum simulations to mimic ejecta generation in two-shockwave target experiments, where metallic surface is loaded by two successive shock waves. Time of second shock in simulations is determined to match experimental amplitudes at the arrival of the second shock. The negative Atwood number A --> - 1 of ejecta simulations leads to two successive phase inversions of the interface corresponding to the passage of the shocks from heavy to light media in each instance. Metallic phase of ejecta (solid/liquid) depends on shock loading pressure in the experiment, and we find that hydrodynamic simulations quantify the liquid phase ejecta physics with a fair degree of accuracy, where RM instability is not suppressed by the strength effect. In particular, we find that our results of free surface velocity, maximum ejecta velocity, and maximum ejecta areal density are in excellent agreement with their experimental counterparts, as well as ejecta models. We also comment on the parametric space for hydrodynamic simulations in which they can be used to compare with the target experiments. This work was supported in part by the (U.S.) Department of Energy (DOE) under Contract No. DE-AC52-06NA2-5396.

  14. Numerical simulations of the flow with the prescribed displacement of the airfoil and comparison with experiment

    NASA Astrophysics Data System (ADS)

    Řidký, V.; Šidlof, P.; Vlček, V.

    2013-04-01

    The work is devoted to comparing measured data with the results of numerical simulations. As mathematical model was used mathematical model whitout turbulence for incompressible flow In the experiment was observed the behavior of designed NACA0015 airfoil in airflow. For the numerical solution was used OpenFOAM computational package, this is open-source software based on finite volume method. In the numerical solution is prescribed displacement of the airfoil, which corresponds to the experiment. The velocity at a point close to the airfoil surface is compared with the experimental data obtained from interferographic measurements of the velocity field. Numerical solution is computed on a 3D mesh composed of about 1 million ortogonal hexahedron elements. The time step is limited by the Courant number. Parallel computations are run on supercomputers of the CIV at Technical University in Prague (HAL and FOX) and on a computer cluster of the Faculty of Mechatronics of Liberec (HYDRA). Run time is fixed at five periods, the results from the fifth periods and average value for all periods are then be compared with experiment.

  15. An observational comparison of the older and younger bus passenger experience in a developing world city.

    PubMed

    Aceves-González, Carlos; May, Andrew; Cook, Sharon

    2016-06-01

    This study was an unobtrusive observational analysis of 333 older and younger bus passengers in Guadalajara, Mexico. A set of data were collected for each observed passenger, as well as more general observations related to driver behaviour, bus design and bus service characteristics. There were significant differences between older and younger passengers in terms of boarding and alighting times, use of handrails, seat location preferences, passenger stability and coping strategies in order to maintain postural stability. The conditions of travel are conducive to a poor passenger experience for the older passengers in particular. Although the problems may be attributed to bus design and driver behaviour typical of that in developing countries, they are also influenced by the wider transport infrastructure, and a lack of a regulatory regime which places drivers under time pressure and in direct competition with each other. Practitioner Summary: Bus services must cater for all ages of passengers, including the elderly. This unobtrusive observational study investigated the passenger experience in a developing world city. Bus and wider service design were found to compromise the journey experience, with the older users being particularly negatively impacted. Design recommendations are provided.

  16. Comparison of continuous and discontinuous collisional bumpers: Dimensionally scaled impact experiments into single wire meshes

    NASA Technical Reports Server (NTRS)

    Hoerz, Friedrich; Cintala, Mark; See, Thomas; Bernhard, Ronald; Cardenas, Frank; Davidson, William; Haynes, Jerry

    1992-01-01

    An experimental inquiry into the utility of discontinuous bumpers was conducted to investigate the collisional outcomes of impacts into single grid-like targets and to compare the results with more traditional bumper designs that employ continuous sheet stock. We performed some 35 experiments using 6.3 and 3.2 mm diameter spherical soda-lime glass projectiles at low velocities (less than 2.5 km/s) and 13 at velocities between 5 and 6 km/s, using 3.2 mm spheres only. The thrust of the experiments related to the characterization of collisional fragments as a function of target thickness or areal shield mass of both bumper designs. The primary product of these experiments was witness plates that record the resulting population of collisional fragments. Substantial interpretive and predictive insights into bumper performance were obtained. All qualitative observations (on the witness plates) and detailed measurements of displaced masses seem simply and consistently related only to bumper mass available for interaction with the impactor. This renders the grid bumper into the superior shield design. These findings present evidence that discontinuous bumpers are a viable concept for collisional shields, possibly superior to continuous geometries.

  17. Quantum state-resolved, bulk gas energetics: Comparison of theory and experiment.

    PubMed

    McCaffery, Anthony J

    2016-05-21

    Until very recently, the computational model of state-to-state energy transfer in large gas mixtures, introduced by the author and co-workers, has had little experimental data with which to assess the accuracy of its predictions. In a novel experiment, Alghazi et al. [Chem. Phys. 448, 76 (2015)] followed the equilibration of highly vibrationally excited CsH(D) in baths of H2(D2) with simultaneous time- and quantum state-resolution. Modal temperatures of vibration, rotation, and translation for CsH(D) were obtained and presented as a function of pump-probe delay time. Here the data from this study are used as a test of the accuracy of the computational method, and in addition, the consequent changes in bath gas modal temperatures, not obtainable in the experiment, are predicted. Despite large discrepancies between initial CsH(D) vibrational states in the experiment and those available using the computational model, the quality of agreement is sufficient to conclude that the model's predictions constitute at least a very good representation of the overall equilibration that, for some measurements, is very accurate.

  18. Computer-assisted comparison of analysis and test results in transportation experiments

    SciTech Connect

    Knight, R.D.; Ammerman, D.J.; Koski, J.A.

    1998-05-10

    As a part of its ongoing research efforts, Sandia National Laboratories` Transportation Surety Center investigates the integrity of various containment methods for hazardous materials transport, subject to anomalous structural and thermal events such as free-fall impacts, collisions, and fires in both open and confined areas. Since it is not possible to conduct field experiments for every set of possible conditions under which an actual transportation accident might occur, accurate modeling methods must be developed which will yield reliable simulations of the effects of accident events under various scenarios. This requires computer software which is capable of assimilating and processing data from experiments performed as benchmarks, as well as data obtained from numerical models that simulate the experiment. Software tools which can present all of these results in a meaningful and useful way to the analyst are a critical aspect of this process. The purpose of this work is to provide software resources on a long term basis, and to ensure that the data visualization capabilities of the Center keep pace with advancing technology. This will provide leverage for its modeling and analysis abilities in a rapidly evolving hardware/software environment.

  19. Electrowetting with contact line pinning: Computational modeling and comparisons with experiments

    NASA Astrophysics Data System (ADS)

    Walker, Shawn W.; Shapiro, Benjamin; Nochetto, Ricardo H.

    2009-10-01

    This work describes the modeling and simulation of planar electrowetting on dielectric devices that move fluid droplets by modulating surface tension effects. The fluid dynamics are modeled by Hele-Shaw type equations with a focus on including the relevant boundary phenomena. Specifically, we include contact angle saturation and a contact line force threshold model that can account for hysteresis and pinning effects. These extra boundary effects are needed to make reasonable predictions of the correct shape and time scale of liquid motion. Without them the simulations can predict droplet motion that is much faster than in experiments (up to 10-20 times faster). We present a variational method for our model, and a corresponding finite element discretization, which is able to handle surface tension, conservation of mass, and the nonlinear contact line pinning in a straightforward and numerically robust way. In particular, the contact line pinning is captured by a variational inequality. We note that all the parameters in our model are derived from first principles or from independent experiments except one (the parameter Dvisc that accounts for the extra resistive effect of contact angle hysteresis and is difficult to measure directly). We quantitatively compare our simulation to available experimental data for four different cases of droplet motion that include splitting and joining of droplets and find good agreement with experiments.

  20. Comparison of fission product release predictions using PARFUME with results from the AGR-1 irradiation experiment

    SciTech Connect

    Blaise Collin

    2014-09-01

    This report documents comparisons between post-irradiation examination measurements and model predictions of silver (Ag), cesium (Cs), and strontium (Sr) release from selected tristructural isotropic (TRISO) fuel particles and compacts during the first irradiation test of the Advanced Gas Reactor program that occurred from December 2006 to November 2009 in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL). The modeling was performed using the particle fuel model computer code PARFUME (PARticle FUel ModEl) developed at INL. PARFUME is an advanced gas-cooled reactor fuel performance modeling and analysis code (Miller 2009). It has been developed as an integrated mechanistic code that evaluates the thermal, mechanical, and physico-chemical behavior of fuel particles during irradiation to determine the failure probability of a population of fuel particles given the particle-to-particle statistical variations in physical dimensions and material properties that arise from the fuel fabrication process, accounting for all viable mechanisms that can lead to particle failure. The code also determines the diffusion of fission products from the fuel through the particle coating layers, and through the fuel matrix to the coolant boundary. The subsequent release of fission products is calculated at the compact level (release of fission products from the compact) but it can be assessed at the particle level by adjusting the diffusivity in the fuel matrix to very high values. Furthermore, the diffusivity of each layer can be individually set to a high value (typically 10-6 m2/s) to simulate a failed layer with no capability of fission product retention. In this study, the comparison to PIE focused on fission product release and because of the lack of failure in the irradiation, the probability of particle failure was not calculated. During the AGR-1 irradiation campaign, the fuel kernel produced and released fission products, which migrated through the successive

  1. Comparison of analysis and experiment for dynamics of low-contact-ratio spur gears

    NASA Technical Reports Server (NTRS)

    Oswald, Fred B.; Rebbechi, Brian; Zakrajsek, James J.; Townsend, Dennis P.; Lin, Hsiang Hsi

    1991-01-01

    Low-contact-ratio spur gears were tested in NASA gear-noise-rig to study gear dynamics including dynamic load, tooth bending stress, vibration, and noise. The experimental results were compared with a NASA gear dynamics code to validate the code as a design tool for predicting transmission vibration and noise. Analytical predictions and experimental data for gear-tooth dynamic loads and tooth-root bending stress were compared at 28 operating conditions. Strain gage data were used to compute the normal load between meshing teeth and the bending stress at the tooth root for direct comparison with the analysis. The computed and measured waveforms for dynamic load and stress were compared for several test conditions. These are very similar in shape, which means the analysis successfully simulates the physical behavior of the test gears. The predicted peak value of the dynamic load agrees with the measurement results within an average error of 4.9 percent except at low-torque, high-speed conditions. Predictions of peak dynamic root stress are generally within 10 to 15 percent of the measured values.

  2. EX-PRESS glaucoma filtration device: Review of clinical experience and comparison with trabeculectomy.

    PubMed

    Shaarawy, Tarek; Goldberg, Ivan; Fechtner, Robert

    2015-01-01

    Glaucoma filtration surgery is performed to reduce intraocular pressure (IOP) in patients for whom maximal tolerable pharmacologic IOP-lowering therapy and/or laser surgery fail to lower IOP sufficiently and/or fail to prevent optic nerve damage or visual field deterioration. For decades, the most widely utilized procedure for glaucoma filtration surgery has been trabeculectomy. Although this approach reliably provides long-term IOP reduction in many patients, the postoperative complication rate is high. This has driven the development of alternative approaches to reduce IOP surgically. The EX-PRESS glaucoma filtration device was developed to mimic IOP control by trabeculectomy and to have a better safety profile. This non-valved, medical-grade stainless steel device diverts aqueous humor from the anterior chamber to an intrascleral space. Despite the widespread use of the EX-PRESS device, only a few studies compare its efficacy and safety with that of trabeculectomy. We analyze available data regarding the safety and efficacy of the EX-PRESS device, particularly in comparison with trabeculectomy.

  3. Sound propagation in and radiation from acoustically lined flow ducts: A comparison of experiment and theory

    NASA Technical Reports Server (NTRS)

    Plumblee, H. E., Jr.; Dean, P. D.; Wynne, G. A.; Burrin, R. H.

    1973-01-01

    The results of an experimental and theoretical study of many of the fundamental details of sound propagation in hard wall and soft wall annular flow ducts are reported. The theory of sound propagation along such ducts and the theory for determining the complex radiation impedance of higher order modes of an annulus are outlined, and methods for generating acoustic duct modes are developed. The results of a detailed measurement program on propagation in rigid wall annular ducts with and without airflow through the duct are presented. Techniques are described for measuring cut-on frequencies, modal phase speed, and radial and annular mode shapes. The effects of flow velocity on cut-on frequencies and phase speed are measured. Comparisons are made with theoretical predictions for all of the effects studies. The two microphone method of impedance is used to measure the effects of flow on acoustic liners. A numerical study of sound propagation in annular ducts with one or both walls acoustically lined is presented.

  4. Composition modulation in GaInNAs quantum wells: Comparison of experiment and theory

    NASA Astrophysics Data System (ADS)

    Herrera, M.; González, D.; Hopkinson, M.; Gutiérrez, M.; Navaretti, P.; Liu, H. Y.; García, R.

    2005-04-01

    Composition modulation observed in GaInNAs quantum wells imposes an important handicap to their potential application within optical components, particularly as the indium and nitrogen contents are increased to reach longer wavelengths. In this paper, we compare our experimental results of phase separation in GaInNAs quantum wells grown at different temperatures with recent theoretical models of spinodal decomposition from the literature. This comparison has shown that the regular solution approximation, which explains the higher composition modulation compared to GaInAs samples, provides a more appropriate explanation of GaInNAs decomposition than the usual delta lattice-parameter approximation. Transmission electron microscopy shows no composition modulation contrasts with the chemical sensitive 002 dark field reflection and a strong increase in the intensity of the strain contrasts observed with 220 bright field reflection as the growth temperature increases from 360to460°C. These observations can be explained by an uncoupling between N and In composition profiles forming separate In-rich and N-rich regions according to the regular solution approximation model. We therefore believe that the compositional fluctuations in GaInNAs are not only due to GaInAs decomposition, but that an uncoupled modulation of the III and V elements is also present.

  5. Optimization design of submerged propeller in oxidation ditch by computational fluid dynamics and comparison with experiments.

    PubMed

    Zhang, Yuquan; Zheng, Yuan; Fernandez-Rodriguez, E; Yang, Chunxia; Zhu, Yantao; Liu, Huiwen; Jiang, Hao

    2016-01-01

    The operating condition of a submerged propeller has a significant impact on flow field and energy consumption of the oxidation ditch. An experimentally validated numerical model, based on the computational fluid dynamics (CFD) tool, is presented to optimize the operating condition by considering two important factors: flow field and energy consumption. Performance demonstration and comparison of different operating conditions were carried out in a Carrousel oxidation ditch at the Yingtang wastewater treatment plants in Anhui Province, China. By adjusting the position and rotating speed together with the number of submerged propellers, problems of sludge deposit and the low velocity in the bend could be solved in a most cost-effective way. The simulated results were acceptable compared with the experimental data and the following results were obtained. The CFD model characterized flow pattern and energy consumption in the full-scale oxidation ditch. The predicted flow field values were within -1.28 ± 7.14% difference from the measured values. By determining three sets of propellers under the rotating speed of 6.50 rad/s with one located 5 m from the first curved wall, after numerical simulation and actual measurement, not only the least power density but also the requirement of the flow pattern could be realized. PMID:27508373

  6. Monte Carlo simulation of molecular flow in a neutral beam injector and comparison with experiment

    SciTech Connect

    Lillie, R.A.; Alsmiller, R.G. Jr.; Gabriel, T.A.; Santoro, R.T.; Schwenterly, S.W.

    1982-04-01

    Monte Carlo calculations have been performed to obtain estimates of the background gas pressure and molecular number density as a function of position in the PDX-prototype neutral beam injector, which has undergone testing at the Oak Ridge National Laboratory. Estimates of these quantities together with the transient and steady-state energy deposition and molecular capture rates on the cryopanels of the cryocondensation pumps and the molecular escape rate from the injector were obtained utilizing a detailed geometric model of the neutral beam injector. The molecular flow calculations were performed using an existing Monte Carlo radiation transport code, which was modified slightly to monitor the energy of the background gas molecules. The credibility of these calculations is demonstrated by the excellent agreement between the calculated and experimentally measured background gas pressure in front of the beamline calorimeter located in the downstream drift region of the injector. The usefulness of the calculational method as a design tool is illustrated by a comparison of the integrated beamline molecular density over the drift region of the injector for three modes of cryopump operation.

  7. Monte Carlo simulation of molecular flow in a neutral-beam injector and comparison with experiment

    SciTech Connect

    Lillie, R.A.; Gabriel, T.A.; Schwenterly, S.W.; Alsmiller, R.G. Jr.; Santoro, R.T.

    1981-09-01

    Monte Carlo calculations have been performed to obtain estimates of the background gas pressure and molecular number density as a function of position in the PDX-prototype neutral beam injector which has undergone testing at the Oak Ridge National Laboratory. Estimates of these quantities together with the transient and steady-state energy deposition and molecular capture rates on the cryopanels of the cryocondensation pumps and the molecular escape rate from the injector were obtained utilizing a detailed geometric model of the neutral beam injector. The molecular flow calculations were performed using an existing Monte Carlo radiation transport code which was modified slightly to monitor the energy of the background gas molecules. The credibility of these calculations is demonstrated by the excellent agreement between the calculated and experimentally measured background gas pressure in front of the beamline calorimeter located in the downstream drift region of the injector. The usefulness of the calculational method as a design tool is illustrated by a comparison of the integrated beamline molecular density over the drift region of the injector for three modes of cryopump operation.

  8. A newly designed compact remote TDL sensing system for air pollutants -- Field experiments and comparison measurements

    SciTech Connect

    Fischer, A.; Herzog, R.; Lamp, T.; Ropertz, A.; Weber, K.

    1999-07-01

    The remote sensing system for local or diffuse concentrations of gaseous air pollutants developed and realized by the ILK Dresden is a very compact and low mass apparatus based on the tunable diode laser (TDL) techniques in pulse or cw mode regime. The prototypes are characterized by compact design (300x150x300mm3) and stand-alone and mains-independent operation that allows a fast, flexible and mobile use in different applications. The first hardware version works as an one laser monitor while the advanced version provides for the simultaneous operation of two lasers and can thus measure two gaseous pollutants at the same time. The sensitivity limits for CO and NO were determined at 13ppb x 100m and at 22ppb x 100m respectively. Optical measurement paths are possible up to 700m. The paper presented results of field measurements of the gaseous pollutants in the open atmosphere, i.e. traffic-induced CO and NO as well as CH{sub 4} and NH{sub 3} landfill gases. Furthermore, the authors have investigated in co-operation with the FH Duesseldorf the ILK TDL-system and commercial remote sensing systems for air pollutant monitoring, especially the FTIR and DOAS systems, in different comparison measurements under real field conditions.

  9. Comparison of Finite Element Predictions to Measurements from the Sandia Microslip Experiment

    SciTech Connect

    LOBITZ,DONALD W.; GREGORY,DANNY LYNN; SMALLWOOD,DAVID O.

    2000-11-09

    When embarking on an experimental program for purposes of discovery and understanding, it is only prudent to use appropriate analysis tools to aid in the discovery process. Due to the limited scope of experimental measurement analytical results can significantly complement the data after a reasonable validation process has occurred. In this manner the analytical results can help to explain certain measurements, suggest other measurements to take and point to possible modifications to the experimental apparatus. For these reasons it was decided to create a detailed nonlinear finite element model of the Sandia Microslip Experiment. This experiment was designed to investigate energy dissipation due to microslip in bolted joints and to identify the critical parameters involved. In an attempt to limit the microslip to a single interface a complicated system of rollers and cables was devised to clamp the two slipping members together with a prescribed normal load without using a bolt. An oscillatory tangential load is supplied via a shaker. The finite element model includes the clamping device in addition to the sequence of steps taken in setting up the experiment. The interface is modeled using Coulomb friction requiring a modest validation procedure for estimating the coefficient of friction. Analysis results have indicated misalignment problems in the experimental procedure, identified transducer locations for more accurate measurements, predicted complex interface motions including the potential for galling, identified regions where microslip occurs and during which parts of the loading cycle it occurs, all this in addition to the energy dissipated per cycle. A number of these predictions have been experimentally corroborated in varying degrees and are presented in the paper along with the details of the finite element model.

  10. Comparison of Aerosol Single Scattering Albedos Derived by Diverse Techniques In Two North Atlantic Experiments

    NASA Technical Reports Server (NTRS)

    Russell, P. B.; Redemann, J.; Schmid, B.; Bergstrom, R. W.; Livingston, J. M.; McIntosh, D. M.; Ramirez, S. A.; Hartley, S.; Hobbs, P. V.; Quinn, P. K.

    2002-01-01

    Aerosol single scattering albedo omega (the ratio of scattering to extinction) is important in determining aerosol climatic effects, in explaining relationships between calculated and measured radiative fluxes, and in retrieving aerosol optical depths from satellite radiances. Recently, two experiments in the North Atlantic region, the Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX) and the Second Aerosol Characterization Experiment (ACE-2), determined aerosol omega by a variety of techniques. The techniques included fitting of calculated to measured radiative fluxes; retrievals of omega from skylight radiances; best fits of complex refractive index to profiles of backscatter extinction, and size distribution; and in situ measurements of scattering and absorption at the surface and aloft. Both TARFOX and ACE-2 found a fairly wide range of values for omega at midvisable wavelengths approx. 550 nm, with omega(sub midvis) greater than or equal to 0.85 and less than or equal to 0.99 for the marine aerosol impacted by continental pollution. Frequency distributions of omega could usually be approximated by lognormals in omega(sub max) - omega, with some occurrence of bimodality, suggesting the influence of different aerosol sources or processing. In both TARFOX and ACE-2, closure tests between measured and calculated radiative fluxes yielded best-fit values of omega(sub midvis) 0.90 +/- 0.04 for the polluted boundary layer. Although these results have the virtue of describing the column aerosol unperturbed by sampling, they are subject to questions about representativeness and other uncertainties (e.g., thermal offsets, unknown gas absorption) The other techniques gave larger values for omega(sub midvis) for the polluted boundary layer, with a typical result of omega(sub midvis) = 0.95 +/- 0.04. Current uncertainties in omega are large in terms of climate effects More tests are needed of the consistency among different methods and of

  11. A Comparison of Seismicity Characteristics and Fault Structure Between Stick-Slip Experiments and Nature

    NASA Astrophysics Data System (ADS)

    Goebel, T. H. W.; Sammis, C. G.; Becker, T. W.; Dresen, G.; Schorlemmer, D.

    2015-08-01

    Fault zones contain structural complexity on all scales. This complexity influences fault mechanics including the dynamics of large earthquakes as well as the spatial and temporal distribution of small seismic events. Incomplete earthquake records, unknown stresses, and unresolved fault structures within the crust complicate a quantitative assessment of the parameters that control factors affecting seismicity. To better understand the relationship between fault structure and seismicity, we examined dynamic faulting under controlled conditions in the laboratory by creating saw-cut-guided natural fractures in cylindrical granite samples. The resulting rough surfaces were triaxially loaded to produce a sequence of stick-slip events. During these experiments, we monitored stress, strain, and seismic activity. After the experiments, fault structures were imaged in thin sections and using computer tomography. The laboratory fault zones showed many structural characteristics observed in upper crustal faults, including zones of localized slip embedded in a layer of fault gouge. Laboratory faults also exhibited a several millimeter wide damage zone with decreasing micro-crack density at larger distances from the fault axis. In addition to the structural similarities, we also observed many similarities between our observed distribution of acoustic emissions (AEs) and natural seismicity. The AEs followed the Gutenberg-Richter and Omori-Utsu relationships commonly used to describe natural seismicity. Moreover, we observed a connection between along-strike fault heterogeneity and variations of the Gutenberg-Richter b value. As suggested by natural seismicity studies, areas of low b value marked the nucleation points of large slip events and were located at large asperities within the fault zone that were revealed by post-experimental tomography scans. Our results emphasize the importance of stick-slip experiments for the study of fault mechanics. The direct correlation of

  12. Comparisons of brightness temperature measurements and calculations obtained during the spectral radiance experiment

    SciTech Connect

    Han, Y.; Snider, J.B.; Westwater, E.R.; Melfi, S.H.; Ferrare, R.A.

    1995-04-01

    In radiometric remote sensing of the atmosphere, the ability to calculate radiances from underlying state variables is fundamental. To infer temperature and water vapor profiles from satellite- or ground-based radiometers, one must determine cloud-free regions and then calculate clear-sky radiance emerging from the top of the earth`s atmosphere from the underlying profiles of temperature and water vapor. Equally important is the validation of the radiometric retrievals. Usually such validation is made by comparing retrievals with profiles derived from other sensors. Traditionally, such {open_quotes}forward model{close_quotes} calculations and validations have coupled radiosonde observations of the state variables with detailed absorption and radiative transfer models. However, for a variety of reasons, radiosonde moisture measurements are not always satisfactory, especially during low humidity conditions or when there are large horizontal or temporal gradients in the humidity structure. A recent alternative to radiosonde moisture measurements is Raman lidar. The Raman lidar provides humidity measurements with temporal and spatial resolution far superior to radiosonde measurements. In November-December 1991, a substantial number of remote sensor and in-situ instruments were operated together in Coffeyville, Kansas, during the First ISCCP Regional Experiment (FIRE) 11. Included in the suite of instruments were (1) the Environmental Technology Laboratory`s (ETL) three-channel microwave radiometer, (2) the NASA/Goddard Space Flight Center`s (GSFC) Raman lidar, (3) ETL`s radio acoustic sounding system (RASS), and (4) frequent research-quality radiosondes. The Raman lidar operated only at night, and this portion of the experiment focused on cloud-free conditions. In this presentation, we present results of simultaneous microwave radiometer measurements with collocated Raman lidar measurements of water vapor over 10 nights during the experiments.

  13. Comparison of patients' experiences in public and private primary care clinics in Malta.

    PubMed

    Pullicino, Glorianne; Sciortino, Philip; Calleja, Neville; Schäfer, Willemijn; Boerma, Wienke; Groenewegen, Peter

    2015-06-01

    Demographic changes, technological developments and rising expectations require the analysis of public-private primary care (PC) service provision to inform policy makers. We conducted a descriptive, cross-sectional study using the dataset of the Maltese arm of the QUALICOPC Project to compare the PC patients' experiences provided by public-funded and private (independent) general practitioners in Malta. Seven hundred patients from 70 clinics completed a self-administered questionnaire. Direct logistic regression showed that patients visiting the private sector experienced better continuity of care with more difficulty in accessing out-of-hours care. Such findings help to improve (primary) healthcare service provision and resource allocation.

  14. Simulation Of Ion Implantation Into Nuclear Materials And Comparison With Experiment

    NASA Astrophysics Data System (ADS)

    Insepov, Z.; Yun, D.; Ye, B.; Rest, J.; Starikov, S.; Yacout, A. M.

    2011-06-01

    A new many-body potential is proposed for pure molybdenum that consists of using ab initio and atomistic MD simulation methods verified against existing surface erosion experimental data. Mo is an important material for metallic U-Mo alloys for using them in low-enriched fuels. Several new Xe-Mo potentials were also parameterized by comparing the calculated sputtering yield of a Mo-surface bombarded with Xe ions with experimental data. Calculated results were also compared with defect distributions in CeO2 crystals obtained from experiments by 500 keV Xe implantation at the doses of 1×1017 ions/cm2 at several temperatures.

  15. Quasi-cylindrical theory of wing-body interference at supersonic speeds and comparison with experiment

    NASA Technical Reports Server (NTRS)

    Nielsen, Jack N

    1955-01-01

    A theoretical method is presented for calculating the flow field about wing-body combinations employing bodies deviating only slightly in shape from a circular cylinder. The method is applied to the calculation of the pressure field acting between a circular cylindrical body and a rectangular wing. The case of zero body angle of attack and variable wing incidence is considered as well as the case of zero wing incidence and variable body angle of attack. An experiment was performed especially for the purpose of checking the calculative examples.

  16. A damage model for rock fragmentation and comparison of calculations with blasting experiments in granite

    SciTech Connect

    Thorne, B.J.

    1990-10-01

    Early attempts at estimation of stress wave damage due to blasting by use of finite element calculations met with limited success due to numerical instabilities that prevented calculations from being carried to late times. An improved damage model allows finite element calculations which remain stable at late times. Reasonable agreement between crater profiles calculated with this model using the PRONTO finite element program and excavated crater profiles from blasting experiments in granite demonstrate a successful application of this model. Detailed instructions for use of this new damage model with the PRONTO finite element programs are included. 18 refs., 16 figs.

  17. HAMLET -Matroshka IIA and IIB experiments aboard the ISS: comparison of organ doses

    NASA Astrophysics Data System (ADS)

    Kato, Zoltan; Reitz, Guenther; Berger, Thomas; Bilski, Pawel; Hajek, Michael; Sihver, Lembit; Palfalvi, Jozsef K.; Hager, Luke; Burmeister, Soenke

    The Matroshka experiments and the related FP7 HAMLET project aimed to study the dose burden of the cosmic rays in the organs of the crew working inside and outside the ISS. Two of the experiments will be discussed. They were performed in two different locations inside the ISS: during the Matroshka 2A (in 2006) the phantom was stored in the Russian Docking Module (Pirs), while during the Matroshka 2B (in 2007-08) it was inside the Russian Service Module (Zvezda). Both experiments were performed in the decreasing phase of the solar cycle. Solid state nuclear track detectors (SSNTD) were applied to investigate the dose contribution of the high LET radiation above ˜10 keV/µm. Two configurations of SSNTDs stacks were constructed: one for the exposure in the so called organ dose boxes (in the lung and kidney), another one for the skin dose measurements, embedded in the nomex poncho of the Phantom. In addition a reference package was placed outside the phantom. After exposure the detectors were transferred to the Earth for data evaluation. Short and long etching procedures were applied to distinguish the high and low LET particles, respectively. The particle tracks were evaluated by a semi automated image analyzer. Addi-tionally manual track parameter measurements were performed on very long tracks. As the result of measurements the LET spectra were deduced. Based on these spectra, the absorbed dose, the dose equivalent and the mean quality factor were calculated. The configuration of the stacks, the methods of the calibration and evaluation and finally the results will be presented and compared. The multiple etching and the combined evaluation method allowed to determine the fraction of the dose originated from HZE particles (Z>2 and range > major axis). Further on, data eval-uation was performed to separate the secondary particles (target fragments) from the primary particles. Although the number of high LET particles above a ˜80 keV/µm was found to be higher during

  18. [Comparison of the Results of Satellite Studies of "Mars-500" Experiment Participans in Syktyvkar and Almaty].

    PubMed

    Solonin, Iu G; Markov, A L; Bojko, E R; Akanov, A A; Yeshmanova, A K

    2015-01-01

    Participants of "Mars-500" experiment living in Syktyvkar (northerners) and Almaty (southerners) were studied throughout the year in various seasons. Latitude-caused differences of vegetative index values (RMSSD and pNN50) between groups were found in summer. Northerners were found to have significant seasonal shifts in thermoregulation parameters and RMSSD and pNN50 values. Southerners showed no seasonal changes in abovementioned indices. Participants from both groups were shown to have deviations of several physiological parameters from moderate latitude norms. Many participants from both groups demonstrated stress in adaptation mechanisms. Orthostatic tests performed in both groups revealed deficiencies in regulation of blood circulation.

  19. Comparison of Constitutive Relationships of Tubes Established Using Uniaxial Tensile Tests and Tube Hydroforming Experiments

    NASA Astrophysics Data System (ADS)

    Li, Jing; Yang, Lianfa

    2016-08-01

    The aim of the present paper is to evaluate existing constitutive models and to fitting hardening laws of SS304 tubes for the accurate prediction of the deformation behaviors of the tubes in hydroforming. Uniaxial tensile test (UTT) and free hydro-bugling (FHB) experiments were conducted on SS304 tubes, and a hi-speed three-dimensional (3D) digital image correlation (DIC) system was applied to obtain the deformation data of the samples. Eight constitutive relationships of the tubes were then established by fitting the equivalent stress and strain data with the four existing constitutive models of Hollomon, Ghosh, Voce and Ghosh/Voce, and the fitting accuracy of the obtained constitutive relationships were analyzed and compared. The results show that Ghosh/Voce model holds the highest accuracy in describing the deformation behaviors of the tubes in UTT and FHB, followed by the Ghosh model and then the Hollomon model. The Voce model holds the lowest accuracy. A distinct discrepancy between the constitutive relationships obtained using UTT and FHB experiments are observed in present research conditions.

  20. Sedimentation equilibria in polydisperse ferrofluids: critical comparisons between experiment, theory, and computer simulation.

    PubMed

    Elfimova, Ekaterina A; Ivanov, Alexey O; Lakhtina, Ekaterina V; Pshenichnikov, Alexander F; Camp, Philip J

    2016-05-14

    The sedimentation equilibrium of dipolar particles in a ferrofluid is studied using experiment, theory, and computer simulation. A theory of the particle-concentration profile in a dipolar hard-sphere fluid is developed, based on the local-density approximation and accurate expressions from a recently introduced logarithmic free energy approach. The theory is tested critically against Monte Carlo simulation results for monodisperse and bidisperse dipolar hard-sphere fluids in homogeneous gravitational fields. In the monodisperse case, the theory is very accurate over broad ranges of gravitational field strength, volume fraction, and dipolar coupling constant. In the bidisperse case, with realistic dipolar coupling constants and compositions, the theory is excellent at low volume fraction, but is slightly inaccurate at high volume fraction in that it does not capture a maximum in the small-particle concentration profile seen in simulations. Possible reasons for this are put forward. Experimental measurements of the magnetic-susceptibility profile in a real ferrofluid are then analysed using the theory. The concentration profile is linked to the susceptibility profile using the second-order modified mean-field theory. It is shown that the experimental results are not consistent with the sample being monodisperse. By introducing polydispersity in the simplest possible way, namely by assuming the system is a binary mixture, almost perfect agreement between theory and experiment is achieved.

  1. Comparison of Computational Results with a Low-g, Nitrogen Slosh and Boiling Experiment

    NASA Technical Reports Server (NTRS)

    Stewart, Mark E.; Moder, Jeffrey P.

    2015-01-01

    This paper compares a fluid/thermal simulation, in Fluent, with a low-g, nitrogen slosh and boiling experiment. In 2010, the French Space Agency, CNES, performed cryogenic nitrogen experiments in a low-g aircraft campaign. From one parabolic flight, a low-g interval was simulated that focuses on low-g motion of nitrogen liquid and vapor with significant condensation, evaporation, and boiling. The computational results are compared with high-speed video, pressure data, heat transfer, and temperature data from sensors on the axis of the cylindrically shaped tank. These experimental and computational results compare favorably. The initial temperature stratification is in good agreement, and the two-phase fluid motion is qualitatively captured. Temperature data is matched except that the temperature sensors are unable to capture fast temperature transients when the sensors move from wet to dry (liquid to vapor) operation. Pressure evolution is approximately captured, but condensation and evaporation rate modeling and prediction need further theoretical analysis.

  2. Forced imbibition in natural porous media: comparison between experiments and continuum models.

    PubMed

    Riaz, Amir; Tang, Guo-Qing; Tchelepi, Hamdi A; Kovscek, Anthony R

    2007-03-01

    A well-characterized set of large-scale laboratory experiments is presented, illustrating forced imbibition displacements in the presence of irreducible wetting phase saturation in a cylindrical, homogeneous Berea sandstone rock. Experiments are designed to operate in the regime of compact microscopic flows and large-scale viscous instability. The distribution of fluid phases during the flow process is visualized by high-resolution computed tomography imaging. Linear stability analysis and high-accuracy numerical simulations are employed to analyze the ability of macroscopic continuum equations to provide a consistent approximation of the displacement process. The validity of the equilibrium relative permeability functions, which form the basis for the continuum model, is fundamentally related to the stability of the displacement process. It is shown that not only is the stable flow regime modeled accurately by existing continuum models, but the onset of instability as well as the initial unstable modes are also determined with reasonable accuracy for unstable flows. However, the continuum model is found to be deficient in the case of fully developed unstable flows.

  3. Comparison of Aseptic Compounding Errors Before and After Modified Laboratory and Introductory Pharmacy Practice Experiences

    PubMed Central

    Owora, Arthur H.; Kirkpatrick, Alice E.

    2015-01-01

    Objective. To determine whether aseptic compounding errors were reduced at the end of the third professional year after modifying pharmacy practice laboratories and implementing an institutional introductory pharmacy practice experience (IPPE). Design. An aseptic compounding laboratory, previously occurring during the third-year spring semester, was added to the second-year spring semester. An 80-hour institutional IPPE was also added in the summer between the second and third years. Instructors recorded aseptic compounding errors using a grading checklist for second-year and third-year student assessments. Third-year student aseptic compounding errors were assessed prior to the curricular changes and for 2 subsequent years for students on the Oklahoma City and Tulsa campuses of the University of Oklahoma. Assessment. Both third-year cohorts committed fewer aseptic technique errors than they did during their second years, and the probability was significantly lower for students on the Oklahoma City campus. The probability of committing major aseptic technique errors was significantly lower for 2 consecutive third-year cohorts after the curricular changes. Conclusion. The addition of second-year aseptic compounding laboratory experiences and third-year institutional IPPE content reduced instructor-assessed errors at the end of the third year. PMID:26889070

  4. Comparison of Raman Scattering Measurements and Modeling in NIF Ignition Experiments

    SciTech Connect

    Strozzi, D J; Hinkel, D E; Williams, E A; Town, R J; Michel, P A; Divol, L; Berger, R L; Moody, J D

    2011-11-04

    Recent NIF indirect-drive experiments have shown significant Raman scattering from the inner beams. NIF data has motivated improvements to rad-hydro modeling, leading to the 'high flux model' [M. D. Rosen et al., HEDP 7, 180 (2011)]. Cross-beam energy transfer [P. A. Michel et al., Phys. Plasmas 17, 056305 (2010] in the laser entrance hole is an important tool for achieving round implosions, and is uniformly distributed across the laser spot in rad-hydro simulations (but not necessarily in experiments). We find the Raman linear gain spectra computed with these plasma conditions agree well in time-dependent peak wavelength with the measured data, especially when overlapping laser-beam intensities are used. More detailed, spatially non-uniform modeling of the cross-beam transfer has been performed. The resulting gains better follow the time history of the measured backscatter. We shall present the impact of spatially non-uniform energy transfer on SRS gain. This metric is valid when amplification is in a linear regime, and so we shall also present an assessment of whether electron trapping in Langmuir waves can play a role in these shots.

  5. Calculation of Oxygen Fugacity in High Pressure Metal-Silicate Experiments and Comparison to Standard Approaches

    NASA Technical Reports Server (NTRS)

    Righter, K.; Ghiorso, M.

    2009-01-01

    Calculation of oxygen fugacity in high pressure and temperature experiments in metal-silicate systems is usually approximated by the ratio of Fe in the metal and FeO in the silicate melt: (Delta)IW=2*log(X(sub Fe)/X(sub FeO)), where IW is the iron-wustite reference oxygen buffer. Although this is a quick and easy calculation to make, it has been applied to a huge variety of metallic (Fe- Ni-S-C-O-Si systems) and silicate liquids (SiO2, Al2O3, TiO2, FeO, MgO, CaO, Na2O, K2O systems). This approach has surely led to values that have little meaning, yet are applied with great confidence, for example, to a terrestrial mantle at "IW-2". Although fO2 can be circumvented in some cases by consideration of Fe-M distribution coefficient, these do not eliminate the effects of alloy or silicate liquid compositional variation, or the specific chemical effects of S in the silicate liquid, for example. In order to address the issue of what the actual value of fO2 is in any given experiment, we have calculated fO2 from the equilibria 2Fe (metal) + SiO2 (liq) + O2 = Fe2SiO4 (liq).

  6. Numerical simulation of mud erosion rate in sand-mud alternate layer and comparison with experiment

    NASA Astrophysics Data System (ADS)

    Yoshida, T.; Yamaguchi, T.; Oyama, H.; Sato, T.

    2015-12-01

    For gas production from methane hydrates in sand-mud alternate layers, depressurization method is expected as feasible. After methane hydrate is dissociated, gas and water flow in pore space. There is a concern about the erosion of mud surface and it may result in flow blockage that disturbs the gas production. As a part of a Japanese National hydrate research program (MH21, funded by METI), we developed a numerical simulation of water-induced mud erosion in pore-scale sand-mud domains to model such mud erosion. The size of which is of the order of 100 micro meter. Water flow is simulated using a lattice Boltzmann method (LBM) and mud surface is treated as solid boundary with arbitrary shape, which changes with time. Periodic boundary condition is adopted at the domain boundaries, except for the surface of mud layers and the upper side. Shear stress acting on the mud surface is calculated using a momentum-exchange method. Mud layer is eroded when the shear stress exceeds a threshold coined a critical shear stress. In this study, we compared the simulated mud erosion rate with experimental data acquired from an experiment using artificial sand-mud core. As a result, the simulated erosion rate agrees well with that of the experiment.

  7. Numerical Calculations of 3-D High-Lift Flows and Comparison with Experiment

    NASA Technical Reports Server (NTRS)

    Compton, William B, III

    2015-01-01

    Solutions were obtained with the Navier-Stokes CFD code TLNS3D to predict the flow about the NASA Trapezoidal Wing, a high-lift wing composed of three elements: the main-wing element, a deployed leading-edge slat, and a deployed trailing-edge flap. Turbulence was modeled by the Spalart-Allmaras one-equation turbulence model. One case with massive separation was repeated using Menter's two-equation SST (Menter's Shear Stress Transport) k-omega turbulence model in an attempt to improve the agreement with experiment. The investigation was conducted at a free stream Mach number of 0.2, and at angles of attack ranging from 10.004 degrees to 34.858 degrees. The Reynolds number based on the mean aerodynamic chord of the wing was 4.3 x 10 (sup 6). Compared to experiment, the numerical procedure predicted the surface pressures very well at angles of attack in the linear range of the lift. However, computed maximum lift was 5% low. Drag was mainly under predicted. The procedure correctly predicted several well-known trends and features of high-lift flows, such as off-body separation. The two turbulence models yielded significantly different solutions for the repeated case.

  8. Sedimentation equilibria in polydisperse ferrofluids: critical comparisons between experiment, theory, and computer simulation.

    PubMed

    Elfimova, Ekaterina A; Ivanov, Alexey O; Lakhtina, Ekaterina V; Pshenichnikov, Alexander F; Camp, Philip J

    2016-05-14

    The sedimentation equilibrium of dipolar particles in a ferrofluid is studied using experiment, theory, and computer simulation. A theory of the particle-concentration profile in a dipolar hard-sphere fluid is developed, based on the local-density approximation and accurate expressions from a recently introduced logarithmic free energy approach. The theory is tested critically against Monte Carlo simulation results for monodisperse and bidisperse dipolar hard-sphere fluids in homogeneous gravitational fields. In the monodisperse case, the theory is very accurate over broad ranges of gravitational field strength, volume fraction, and dipolar coupling constant. In the bidisperse case, with realistic dipolar coupling constants and compositions, the theory is excellent at low volume fraction, but is slightly inaccurate at high volume fraction in that it does not capture a maximum in the small-particle concentration profile seen in simulations. Possible reasons for this are put forward. Experimental measurements of the magnetic-susceptibility profile in a real ferrofluid are then analysed using the theory. The concentration profile is linked to the susceptibility profile using the second-order modified mean-field theory. It is shown that the experimental results are not consistent with the sample being monodisperse. By introducing polydispersity in the simplest possible way, namely by assuming the system is a binary mixture, almost perfect agreement between theory and experiment is achieved. PMID:27042815

  9. Comparison of the calorimetric and kinematic methods of neutrino energy reconstruction in disappearance experiments

    DOE PAGES

    Ankowski, Artur M.; Benhar, Omar; Coloma, Pilar; Huber, Patrick; Jen, Chun -Min; Mariani, Camillo; Meloni, Davide; Vagnoni, Erica

    2015-10-22

    To be able to achieve their physics goals, future neutrino-oscillation experiments will need to reconstruct the neutrino energy with very high accuracy. In this work, we analyze how the energy reconstruction may be affected by realistic detection capabilities, such as energy resolutions, efficiencies, and thresholds. This allows us to estimate how well the detector performance needs to be determined a priori in order to avoid a sizable bias in the measurement of the relevant oscillation parameters. We compare the kinematic and calorimetric methods of energy reconstruction in the context of two νμ → νμ disappearance experiments operating in different energymore » regimes. For the calorimetric reconstruction method, we find that the detector performance has to be estimated with an O(10%) accuracy to avoid a significant bias in the extracted oscillation parameters. Thus, in the case of kinematic energy reconstruction, we observe that the results exhibit less sensitivity to an overestimation of the detector capabilities.« less

  10. Evaluation of the Monte Carlo method (KTMAN-2) in fluoroscopic dosimetry and comparison with experiment

    NASA Astrophysics Data System (ADS)

    Kim, Minho; Lee, Hyounggun; Kim, Hyosim; Park, Hongmin; Lee, Wonho; Park, Sungho

    2014-03-01

    This study evaluated the Monte Carlo method for determining the dose calculation in fluoroscopy by using a realistic human phantom. The dose was calculated by using Monte Carlo N-particle extended (MCNPX) in simulations and was measured by using Korean Typical Man-2 (KTMAN-2) phantom in the experiments. MCNPX is a widely-used simulation tool based on the Monte-Carlo method and uses random sampling. KTMAN-2 is a virtual phantom written in MCNPX language and is based on the typical Korean man. This study was divided into two parts: simulations and experiments. In the former, the spectrum generation program (SRS-78) was used to obtain the output energy spectrum for fluoroscopy; then, each dose to the target organ was calculated using KTMAN-2 with MCNPX. In the latter part, the output of the fluoroscope was calibrated first and TLDs (Thermoluminescent dosimeter) were inserted in the ART (Alderson Radiation Therapy) phantom at the same places as in the simulation. Thus, the phantom was exposed to radiation, and the simulated and the experimental doses were compared. In order to change the simulation unit to the dose unit, we set the normalization factor (NF) for unit conversion. Comparing the simulated with the experimental results, we found most of the values to be similar, which proved the effectiveness of the Monte Carlo method in fluoroscopic dose evaluation. The equipment used in this study included a TLD, a TLD reader, an ART phantom, an ionization chamber and a fluoroscope.

  11. Comparison of the calorimetric and kinematic methods of neutrino energy reconstruction in disappearance experiments

    SciTech Connect

    Ankowski, Artur M.; Benhar, Omar; Coloma, Pilar; Huber, Patrick; Jen, Chun -Min; Mariani, Camillo; Meloni, Davide; Vagnoni, Erica

    2015-10-22

    To be able to achieve their physics goals, future neutrino-oscillation experiments will need to reconstruct the neutrino energy with very high accuracy. In this work, we analyze how the energy reconstruction may be affected by realistic detection capabilities, such as energy resolutions, efficiencies, and thresholds. This allows us to estimate how well the detector performance needs to be determined a priori in order to avoid a sizable bias in the measurement of the relevant oscillation parameters. We compare the kinematic and calorimetric methods of energy reconstruction in the context of two νμ → νμ disappearance experiments operating in different energy regimes. For the calorimetric reconstruction method, we find that the detector performance has to be estimated with an O(10%) accuracy to avoid a significant bias in the extracted oscillation parameters. Thus, in the case of kinematic energy reconstruction, we observe that the results exhibit less sensitivity to an overestimation of the detector capabilities.

  12. Profile stiffness measurements in the Helically Symmetric experiment and comparison to nonlinear gyrokinetic calculationsa)

    NASA Astrophysics Data System (ADS)

    Weir, G. M.; Faber, B. J.; Likin, K. M.; Talmadge, J. N.; Anderson, D. T.; Anderson, F. S. B.

    2015-05-01

    Stiffness measurements are presented in the quasi-helically symmetric experiment (HSX), in which the neoclassical transport is comparable to that in a tokamak and turbulent transport dominates throughout the plasma. Electron cyclotron emission is used to measure the local electron temperature response to modulated electron cyclotron resonant heating. The amplitude and phase of the heat wave through the steep electron temperature gradient (ETG) region of the plasma are used to determine a transient electron thermal diffusivity that is close to the steady-state diffusivity. The low stiffness in the region between 0.2 ≤ r/a ≤ 0.4 agrees with the scaling of the steady-state heat flux with temperature gradient in this region. These experimental results are compared to gyrokinetic calculations in a flux-tube geometry using the gyrokinetic electromagnetic numerical experiment code with two kinetic species. Linear simulations show that the ETG mode may be experimentally relevant within r/a ≤ 0.2, while the Trapped Electron Mode (TEM) is the dominant long-wavelength microturbulence instability across most of the plasma. The TEM is primarily driven by the density gradient. Non-linear calculations of the saturated heat flux driven by the TEM and ETG bracket the experimental heat flux.

  13. Profile stiffness measurements in the Helically Symmetric experiment and comparison to nonlinear gyrokinetic calculations

    SciTech Connect

    Weir, G. M.; Faber, B. J.; Likin, K. M.; Talmadge, J. N.; Anderson, D. T.; Anderson, F. S. B.

    2015-05-15

    Stiffness measurements are presented in the quasi-helically symmetric experiment (HSX), in which the neoclassical transport is comparable to that in a tokamak and turbulent transport dominates throughout the plasma. Electron cyclotron emission is used to measure the local electron temperature response to modulated electron cyclotron resonant heating. The amplitude and phase of the heat wave through the steep electron temperature gradient (ETG) region of the plasma are used to determine a transient electron thermal diffusivity that is close to the steady-state diffusivity. The low stiffness in the region between 0.2 ≤ r/a ≤ 0.4 agrees with the scaling of the steady-state heat flux with temperature gradient in this region. These experimental results are compared to gyrokinetic calculations in a flux-tube geometry using the gyrokinetic electromagnetic numerical experiment code with two kinetic species. Linear simulations show that the ETG mode may be experimentally relevant within r/a ≤ 0.2, while the Trapped Electron Mode (TEM) is the dominant long-wavelength microturbulence instability across most of the plasma. The TEM is primarily driven by the density gradient. Non-linear calculations of the saturated heat flux driven by the TEM and ETG bracket the experimental heat flux.

  14. Comparison of theory and experiment for solute transport in highly heterogeneous porous medium

    NASA Astrophysics Data System (ADS)

    Golfier, Fabrice; Quintard, Michel; Cherblanc, Fabien; Zinn, Brendan A.; Wood, Brian D.

    2007-11-01

    In this work we compare the recently developed two-region mass transfer theory reported by Ahmadi et al. [A. Ahmadi, M. Quintard, S. Whitaker (1998), Transport in chemically and mechanically heterogeneous porous media, V, two-equation model for solute transport with adsorption, Adv. Water Resour. 1998;22:59-86] with experimental results reported by Zinn et al. [Zinn, B., L. C. Meigs, C. F. Harvey, R. Haggerty, W. J. Peplinski, C. F. Von Schwerin. Experimental visualization of solute transport and mass transfer processes in two-dimensional conductivity fields with connected regions of high conductivity. Environ Sci Technol 2004;38:3916-3926]. We find that the constant mass transfer coefficient predicted by the steady-state closure to the theory, when used with the macroscale transport equation, provides a reasonable prediction of the observed breakthrough curve. However, the use of a constant mass transfer coefficient does not allow good representation of the tailing that is observed in the data. We show that the mass transfer coefficient can be represented in terms of the eigenvalue expansion of a Green's function. For a steady solution to the closure problem, this expansion leads to the effective mass transfer coefficient being defined in terms of the harmonic average of the eigenvalues of the expansion; this is consistent with previous work on this topic. To further investigate the influence of using a single, constant value for the mass transfer coefficient, we examine the solution to the mass transfer problem in terms of a mixed model, where the eigenvalues of one region (the inclusions) are kept, while the second region (the matrix) is treated as a homogenized material. The results from this comparison indicate that the mass transfer coefficient predicted via volume averaging using a quasi-steady closure could potentially be improved upon by development of new methods that retain more of the eigenvalues of the system.

  15. Modelling of tokamak glow discharge cleaning II: comparison with experiment and application to ITER

    NASA Astrophysics Data System (ADS)

    Kogut, D.; Douai, D.; Hagelaar, G.; Pitts, R. A.

    2015-02-01

    The primary function of the ITER glow discharge cleaning (GDC) system will be the preparation of in-vessel component surfaces prior to the machine start-up. It may also contribute to tritium removal in the nuclear phase. In GDC, conditioning efficiency is strongly dependent on the homogeneity of the flux of ions impinging onto wall surfaces. In order to assess the wall particle flux distribution in ITER, a novel 2D multi-fluid model, described in a companion paper, has recently been developed and is benchmarked here against both experimental glow discharge data obtained in a small laboratory chamber with cylindrical geometry and from two large toroidal devices: the JET tokamak and the RFX reverse field pinch. In the laboratory plasma, simulated and measured plasma electron density and temperature are in a good agreement in the negative glow region, while discrepancies exist in the anode glow, where the fluid description of the model is inaccurate due to long mean free paths of electrons. Calculated and measured ion flux distribution profiles in RFX are found in good agreement, whereas in JET comparison it is more difficult, due to the complex geometry of the first wall which leads to local inhomogeneities in the measured flux. Simulations of H2-GDC for ITER with one or two anodes indicate fairly homogeneous plasma parameters and wall ion flux in the negative glow at 0.5 Pa, a commonly used gas pressure for GDC in existing fusion devices. Although the axisymmetric geometry in the model does not allow all seven ITER anodes to be powered simultaneously in the simulations, the results can be extrapolated to the full system and predict ion current densities on wall surfaces close to the simple expectation of total anode current divided by wall surface area (0.21 A m-2), which is relevant to GDC in JET and other machines.

  16. Comparison of particle-in-cell simulation with experiment for thetransport system of the superconducting electron cyclotron resonance ionsource VENUS

    SciTech Connect

    Todd, DamonS.; Leitner, Daniela; Leitner, Matthaeus; Lyneis,Claude M.; Qiang, Ji; Grote, Dave P.

    2005-09-19

    The three-dimensional, particle-in-cell code WARP has been enhanced to allow end-to-end beam dynamics simulations of the VENUS beam transport system from the extraction region, through a mass-analyzing magnet, and up to a two-axis emittance scanner. This paper presents first results of comparisons between simulation and experimental data. A helium beam (He+, He2+) is chosen as an initial comparison beam due to its simple mass spectrum. Although a number of simplifications are made for the initial extracted beam, aberration characteristics appear in simulations that are also present in experimental phase space current density measurements. Further, measurements of phase space tilt indicate that simulations must have little or no space charge neutralization along the transport system to best agree with experiment. In addition, recent measurements of triangular beam structure immediately after the source are presented. This beam structure is related to the source magnetic confinement fields and will need to be taken into account as the initial beam approximations are lifted.

  17. GaMin’11 – an international inter-laboratory comparison for geochemical CO₂ - saline fluid - mineral interaction experiments

    DOE PAGES

    Ostertag-Henning, C.; Risse, A.; Thomas, B.; Rosenbauer, R.; Rochelle, C.; Purser, G.; Kilpatrick, A.; Rosenqvist, J.; Yardley, B.; Karamalidis, A.; et al

    2014-12-31

    Due to the strong interest in geochemical CO₂-fluid-rock interaction in the context of geological storage of CO₂ a growing number of research groups have used a variety of different experimental ways to identify important geochemical dissolution or precipitation reactions and – if possible – quantify the rates and extent of mineral or rock alteration. In this inter-laboratory comparison the gas-fluid-mineral reactions of three samples of rock-forming minerals have been investigated by 11 experimental labs. The reported results point to robust identification of the major processes in the experiments by most groups. The dissolution rates derived from the changes in compositionmore » of the aqueous phase are consistent overall, but the variation could be reduced by using similar corrections for changing parameters in the reaction cells over time. The comparison of experimental setups and procedures as well as of data corrections identified potential improvements for future gas-fluid-rock studies.« less

  18. Chemical kinetic modeling of a methane opposed flow diffusion flame and comparison to experiments

    SciTech Connect

    Marinov, N.M., Pitz, W.J.; Westbrook, C.K.; Vincitore, A.M.; Senka, S.M.; Lutz, A.E.

    1998-01-01

    The chemical structure of an opposed flow, methane diffusion flame is studied using a chemical kinetic model and the results are compared to experimental measurements. The chemical kinetic paths leading to aromatics and polycyclic aromatics hydrocarbons (PAHs) in the diffusion flame are identified. These paths all involve resonantly stabilized radicals which include propargyl, allyl, cyclopentadienyl, and benzyl radicals. The modeling results show reasonable agreement with the experimental measurements for the large hydrocarbon aliphatic compounds, aromatics, and PAHs. the benzene was predicted to be formed primarily by the reaction sequence of Allyl plus Propargyl equals Fulvene plus H plus H followed by fulvene isomerization to benzene. Naphthalene was modeled using the reaction of benzyl with propargyl, while the combination of cyclopentadienyl radicals were shown to be a minor contributor in the diffusion flame. The agreement between the model and experiment for the four-ring PAHs was poor.

  19. Comparison of two methods of performing the Thellier experiment. [paleomagnetic intensity determination

    NASA Technical Reports Server (NTRS)

    Levi, S.

    1975-01-01

    Two methods for performing the Thellier experiment on paleointensity determinations are compared. The first method is essentially that of Coe (1967) and the second is a slight modification of it. Prepared samples containing different species of magnetic particles are used, and both methods are always performed on the same sample. The study is designed to accent procedural differences between the two methods. It is shown that only the Coe method yields linear PNRM-PTRM (Partial ThermoRemanent Magnetization) plots for single domain and pseudo-single domain particles, because it maintains the symmetry between high-temperature VRM (Viscous Remanent Magnetization) and spontaneous decay, whereas for the modified Coe method the spontaneous decay is enhanced. For multidomain remanence, even the Coe method yields a nonlinear concave-up PNRM-PTRM plot. Paleointensity determinations employing only the ratio NRM/TRM provide no means of evaluating the reliability of the results.

  20. Calculation of neutron and gamma ray energy spectra for fusion reactor shield design: comparison with experiment

    SciTech Connect

    Santoro, R.T.; Alsmiller, R.G. Jr.; Barnes, J.M.; Chapman, G.T.

    1980-08-01

    Integral experiments that measure the transport of approx. 14 MeV D-T neutrons through laminated slabs of proposed fusion reactor shield materials have been carried out. Measured and calculated neutron and gamma ray energy spectra are compared as a function of the thickness and composition of stainless steel type 304, borated polyethylene, and Hevimet (a tungsten alloy), and as a function of detector position behind these materials. The measured data were obtained using a NE-213 liquid scintillator using pulse-shape discrimination methods to resolve neutron and gamma ray pulse height data and spectral unfolding methods to convert these data to energy spectra. The calculated data were obtained using two-dimensional discrete ordinates radiation transport methods in a complex calculational network that takes into account the energy-angle dependence of the D-T neutrons and the nonphysical anomalies of the S/sub n/ method.

  1. Calculated rotation-bending energy levels of CH 5+ and a comparison with experiment

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Gang; Carrington, Tucker

    2016-05-01

    We report J > 0 CH 5+ levels computed by fixing stretch coordinates. They are computed by using a simple product basis, exploiting symmetry, and carefully parallelizing the calculation. The J > 0 CH 5+ levels are compared with those obtained from other theoretical methods and with experimental ground state combination differences of Asvany et al. [Science, 347, 1346 (2015)]. If the assignment of Asvany et al. is correct, there are important differences between the levels we compute and those observed. We propose a different assignment of the experimental levels that reduces the maximum error from 34 to 2 cm-1. The new assignment can only be correct if states of both parities exist in the experiment. Although, ro-vibrational levels of CH 5+ cannot be associated with individual vibrational states, they do occur in blocks separated by gaps.

  2. Density-functional study of small interstitial clusters in Si: Comparison with experiments

    SciTech Connect

    Carvalho, A.; Coutinho, J.; Jones, R.; Briddon, P.R.

    2005-10-15

    Local density functional calculations are carried out on models of tri- and tetra-self-interstitial clusters in Si. Electrical levels and local vibrational modes (LVMs) of the defects are found. The latter are compared with recent experiments detailing the isotopic shifts of LVM frequencies associated with phonon replicas of the W- and X-photoluminescence lines, attributed to I{sub 3} ad I{sub 4}, respectively. While the ground state I{sub 4} structure accounts well for the measured optical and electrical data, the most stable I{sub 3} aggregates either show no gap states, or the lack for LVMs that could be linked with the W-line. Instead, this optical center can be linked to a metastable form of I{sub 3}.

  3. Hemolysis Related to Turbulent Eddy Size Distributions Using Comparisons of Experiments to Computations.

    PubMed

    Ozturk, Mesude; O'Rear, Edgar A; Papavassiliou, Dimitrios V

    2015-12-01

    Turbulent blood flow in medical devices contributes to blood trauma, yet the exact mechanism(s) have not been fully elucidated. Local turbulent stresses, viscous stresses, and the rate of dissipation of the turbulent kinetic energy have been proffered as hypotheses to describe and predict blood damage. In this work, simulations of experiments in a Couette flow viscometer and a capillary tube were used to examine extensive properties of the turbulent flow field and to investigate contributing factors for red blood cell hemoglobin release in turbulence by eddy analysis. It was found that hemolysis occurred when dissipative eddies were comparable in size to the red blood cells. The Kolmogorov length scale was used to quantify the size of smaller turbulent eddies, indicating correspondence of hemolysis with number and surface area of eddies smaller than about 10 μm when a k-ε turbulence model is adopted. PMID:26412190

  4. Isentropic Compression with a Rectangular Configuration for Tungstene and Tantalum, Computations and Comparison with Experiments

    SciTech Connect

    Lefrancois, A.; Reisman, D. B.; Bastea, M.; L'Eplattenier, P.; Burger, M.

    2006-02-13

    Isentropic compression experiments and numerical simulations on metals are performed at Z accelerator facility from Sandia National Laboratory and at Lawrence Livermore National Laboratory in order to study the isentrope, associated Hugoniot and phase changes of these metals. 3D configurations have been calculated here to benchmark the new beta version of the electromagnetism package coupled with the dynamics in Ls-Dyna and compared with the ICE Z shots 1511 and 1555. The electromagnetism module is being developed in the general-purpose explicit and implicit finite element program LS-DYNA{reg_sign} in order to perform coupled mechanical/thermal/electromagnetism simulations. The Maxwell equations are solved using a Finite Element Method (FEM) for the solid conductors coupled with a Boundary Element Method (BEM) for the surrounding air (or vacuum). More details can be read in the references.

  5. Isentropic Compression up to 200 KBars for LX 04, Numerical Simulations and Comparison with Experiments

    SciTech Connect

    Lefrancois, A.; Hare, D.; L'Eplattenier, P.; Burger, M.

    2006-02-13

    Isentropic compression experiments and numerical simulations on LX-04 (HMX / Viton 85/15) were performed respectively at Z accelerator facility from Sandia National Laboratory and at Lawrence Livermore National Laboratory in order to study the isentrope and associated Hugoniot of this HE. 2D and 3D configurations have been calculated here to test the new beta version of the electromagnetism package coupled with the dynamics in Ls-Dyna and compared with the ICE Z shot 1067 on LX 04. The electromagnetism module is being developed in the general-purpose explicit and implicit finite element program LS-DYNA{reg_sign} in order to perform coupled mechanical/thermal/electromagnetism simulations. The Maxwell equations are solved using a Finite Element Method (FEM) for the solid conductors coupled with a Boundary Element Method (BEM) for the surrounding air (or vacuum). More details can be read in the references.

  6. Copper Tube Compression in Z-Current Geometry, Numerical Simulations and Comparison with Cyclope Experiments

    SciTech Connect

    Lefrancois, A.; L'Eplattenier, P.; Burger, M.

    2006-02-13

    Metallic tubes compressions in Z-current geometry were performed at the Cyclope facility from Gramat Research Center in order to study the behavior of metals under large strain at high strain rate. 3D configurations of cylinder compressions have been calculated here to benchmark the new beta version of the electromagnetism package coupled with the dynamics in Ls-Dyna and compared with the Cyclope experiments. The electromagnetism module is being developed in the general-purpose explicit and implicit finite element program LS-DYNA{reg_sign} in order to perform coupled mechanical/thermal/electromagnetism simulations. The Maxwell equations are solved using a Finite Element Method (FEM) for the solid conductors coupled with a Boundary Element Method (BEM) for the surrounding air (or vacuum). More details can be read in the references.

  7. Multi-channel transport experiments at Alcator C-Mod and comparison with gyrokinetic simulations

    SciTech Connect

    White, A. E.; Howard, N. T.; Greenwald, M.; Reinke, M. L.; Sung, C.; Baek, S.; Barnes, M.; Dominguez, A.; Ernst, D.; Gao, C.; Hubbard, A. E.; Hughes, J. W.; Lin, Y.; Parra, F.; Porkolab, M.; Rice, J. E.; Walk, J.; Wukitch, S. J.; Team, Alcator C-Mod; Candy, J.; and others

    2013-05-15

    Multi-channel transport experiments have been conducted in auxiliary heated (Ion Cyclotron Range of Frequencies) L-mode plasmas at Alcator C-Mod [Marmar and Alcator C-Mod Group, Fusion Sci. Technol. 51(3), 3261 (2007)]. These plasmas provide good diagnostic coverage for measurements of kinetic profiles, impurity transport, and turbulence (electron temperature and density fluctuations). In the experiments, a steady sawtoothing L-mode plasma with 1.2 MW of on-axis RF heating is established and density is scanned by 20%. Measured rotation profiles change from peaked to hollow in shape as density is increased, but electron density and impurity profiles remain peaked. Ion or electron heat fluxes from the two plasmas are the same. The experimental results are compared directly to nonlinear gyrokinetic theory using synthetic diagnostics and the code GYRO [Candy and Waltz, J. Comput. Phys. 186, 545 (2003)]. We find good agreement with experimental ion heat flux, impurity particle transport, and trends in the fluctuation level ratio (T(tilde sign){sub e}/T{sub e})/(ñ{sub e}/n{sub e}), but underprediction of electron heat flux. We find that changes in momentum transport (rotation profiles changing from peaked to hollow) do not correlate with changes in particle transport, and also do not correlate with changes in linear mode dominance, e.g., Ion Temperature Gradient versus Trapped Electron Mode. The new C-Mod results suggest that the drives for momentum transport differ from drives for heat and particle transport. The experimental results are inconsistent with present quasilinear models, and the strong sensitivity of core rotation to density remains unexplained.

  8. Fully 3D-computations of submarine turbid surges : comparison with flume experiments

    NASA Astrophysics Data System (ADS)

    Cayocca, F.; Le Hir, P.

    2003-04-01

    Most numerical models of submarine gravity currents use layer-averaged equations. The description of the flow properties then requires the use of empirical terms to include 1) water entrainment at the surface of the dense layer and 2) entrainment of sediment by erosion of the seafloor. SiAM3D is a three-dimensional numerical model based on the hydrostatic approximation to solve the mass and momentum conservation equations for highly concentrated mixtures. Stratification turbulence damping, hindered settling and increase of molecular viscosity with concentration (which can lead to a visco-plastic behaviour) are included. Water entrainment results here from the turbulent behaviour of the flow and does not require empirical coefficients as in vertically integrated models. A mixing length turbulence closure is also used to compute bottom friction. Erosion and deposition can be taken into account. The model is used to simulate slope-failure-induced submarine turbid surges. It is compared with data from flume experiments carried out with saline or sediment laden flows. Front velocity, length and concentration of the flow can therefore be validated for various values of slope angle, surge volume and initial density. The hard bottoms used in the experiments found in the literature do not allow the validation of erosion computations. 3D computations were carried out to simulate the submarine landslide generated by the collapse of Nice airport landfill in 1979. Large computation times do not allow simulations long enough for the flow to reach distances where data are available. However the results compare well with simulations produced by a more complex model, the results of which were validated by observed hydraulic effects in front of the airport (landslide-generated tsunami).

  9. 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.

  10. Polarized x-ray-absorption spectroscopy of the uranyl ion: Comparison of experiment and theory

    SciTech Connect

    Hudson, E.A.; Allen, P.G.; Terminello, L.J.; Denecke, M.A.; Reich, T.

    1996-07-01

    The x-ray linear dichroism of the uranyl ion (UO{sub 2}{sup 2+}) in uranium {ital L}{sub 3}-edge extended x-ray-absorption fine structure (EXAFS), and {ital L}{sub 1}- and {ital L}{sub 3}-edge x-ray-absorption near-edge structure (XANES), has been investigated both by experiment and theory. A striking polarization dependence is observed in the experimental XANES and EXAFS for an oriented single crystal of uranyl acetate dihydrate [UO{sub 2}(CH{sub 3}CO{sub 2}){sub 2}{center_dot}2H{sub 2}O], with the x-ray polarization vector aligned either parallel or perpendicular to the bond axis of the linear uranyl cation (O-U-O). Single-crystal results are compared to experimental spectra for a polycrystalline uranyl acetate sample and to calculations using the {ital ab} {ital initio} multiple-scattering (MS) code FEFF 6. Theoretical XANES spectra for uranyl fluoride (UO{sub 2}F{sub 2}) reproduce all the features of the measured uranyl acetate spectra. By identifying scattering paths which contribute to individual features in the calculated spectrum, a detailed understanding of the {ital L}{sub 1}-edge XANES is obtained. MS paths within the uranyl cation have a notable influence upon the XANES. The measured {ital L}{sub 3}-edge EXAFS is also influenced by MS, especially when the x-ray polarization is parallel to the uranyl species. These MS contributions are extracted from the total EXAFS and compared to calculations. The best agreement with the isolated MS signal is obtained by using nonoverlapped muffin-tin spheres in the FEFF 6 calculation. This contrasts the {ital L}{sub 1}-edge XANES calculations, in which overlapping was required for the best agreement with experiment. {copyright} {ital 1996 The American Physical Society.}

  11. Multi-channel transport experiments at Alcator C-Mod and comparison with gyrokinetic simulationsa)

    NASA Astrophysics Data System (ADS)

    White, A. E.; Howard, N. T.; Greenwald, M.; Reinke, M. L.; Sung, C.; Baek, S.; Barnes, M.; Candy, J.; Dominguez, A.; Ernst, D.; Gao, C.; Hubbard, A. E.; Hughes, J. W.; Lin, Y.; Mikkelsen, D.; Parra, F.; Porkolab, M.; Rice, J. E.; Walk, J.; Wukitch, S. J.; Team, Alcator C-Mod

    2013-05-01

    Multi-channel transport experiments have been conducted in auxiliary heated (Ion Cyclotron Range of Frequencies) L-mode plasmas at Alcator C-Mod [Marmar and Alcator C-Mod Group, Fusion Sci. Technol. 51(3), 3261 (2007)]. These plasmas provide good diagnostic coverage for measurements of kinetic profiles, impurity transport, and turbulence (electron temperature and density fluctuations). In the experiments, a steady sawtoothing L-mode plasma with 1.2 MW of on-axis RF heating is established and density is scanned by 20%. Measured rotation profiles change from peaked to hollow in shape as density is increased, but electron density and impurity profiles remain peaked. Ion or electron heat fluxes from the two plasmas are the same. The experimental results are compared directly to nonlinear gyrokinetic theory using synthetic diagnostics and the code GYRO [Candy and Waltz, J. Comput. Phys. 186, 545 (2003)]. We find good agreement with experimental ion heat flux, impurity particle transport, and trends in the fluctuation level ratio (T˜e/Te)/(n ˜e/ne), but underprediction of electron heat flux. We find that changes in momentum transport (rotation profiles changing from peaked to hollow) do not correlate with changes in particle transport, and also do not correlate with changes in linear mode dominance, e.g., Ion Temperature Gradient versus Trapped Electron Mode. The new C-Mod results suggest that the drives for momentum transport differ from drives for heat and particle transport. The experimental results are inconsistent with present quasilinear models, and the strong sensitivity of core rotation to density remains unexplained.

  12. Melts of garnet lherzolite: experiments, models and comparison to melts of pyroxenite and carbonated lherzolite

    USGS Publications Warehouse

    Grove, Timothy L.; Holbig, Eva S.; Barr, Jay A.; Till, Christy B.; Krawczynski, Michael J.

    2013-01-01

    Phase equilibrium experiments on a compositionally modified olivine leucitite from the Tibetan plateau have been carried out from 2.2 to 2.8 GPa and 1,380–1,480 °C. The experiments-produced liquids multiply saturated with spinel and garnet lherzolite phase assemblages (olivine, orthopyroxene, clinopyroxene and spinel ± garnet) under nominally anhydrous conditions. These SiO2-undersaturated liquids and published experimental data are utilized to develop a predictive model for garnet lherzolite melting of compositionally variable mantle under anhydrous conditions over the pressure range of 1.9–6 GPa. The model estimates the major element compositions of garnet-saturated melts for a range of mantle lherzolite compositions and predicts the conditions of the spinel to garnet lherzolite phase transition for natural peridotite compositions at above-solidus temperatures and pressures. We compare our predicted garnet lherzolite melts to those of pyroxenite and carbonated lherzolite and develop criteria for distinguishing among melts of these different source types. We also use the model in conjunction with a published predictive model for plagioclase and spinel lherzolite to characterize the differences in major element composition for melts in the plagioclase, spinel and garnet facies and develop tests to distinguish between melts of these three lherzolite facies based on major elements. The model is applied to understand the source materials and conditions of melting for high-K lavas erupted in the Tibetan plateau, basanite–nephelinite lavas erupted early in the evolution of Kilauea volcano, Hawaii, as well as younger tholeiitic to alkali lavas from Kilauea.

  13. Vibrational non-equilibrium in the hydrogen-oxygen reaction. Comparison with experiment

    NASA Astrophysics Data System (ADS)

    Skrebkov, Oleg V.

    2015-03-01

    A theoretical model is proposed for the chemical and vibrational kinetics of hydrogen oxidation based on consistent accounting of the vibrational non-equilibrium of the HO2 radical that forms as a result of the bimolecular recombination H+O2 → HO2. In the proposed model, the chain branching H+O2 = O+OH and inhibiting H+O2+M = HO2+M formal reactions are treated (in the terms of elementary processes) as a single multi-channel process of forming, intramolecular energy redistribution between modes, relaxation, and unimolecular decay of the comparatively long-lived vibrationally excited HO2 radical, which is able to react and exchange energy with the other components of the mixture. The model takes into account the vibrational non-equilibrium of the starting (primary) H2 and O2 molecules, as well as the most important molecular intermediates HO2, OH, O2(1Δ), and the main reaction product H2O. It is shown that the hydrogen-oxygen reaction proceeds in the absence of vibrational equilibrium, and the vibrationally excited HO2(v) radical acts as a key intermediate in a fundamentally important chain branching process and in the generation of electronically excited species O2(1Δ), O(1D), and OH(2Σ+). The calculated results are compared with the shock tube experimental data for strongly diluted H2-O2 mixtures at 1000 < T < 2500 K, 0.5 < p < 4 atm. It is demonstrated that this approach is promising from the standpoint of reconciling the predictions of the theoretical model with experimental data obtained by different authors for various compositions and conditions using different methods. For T < 1500 K, the nature of the hydrogen-oxygen reaction is especially non-equilibrium, and the vibrational non-equilibrium of the HO2 radical is the essence of this process. The quantitative estimation of the vibrational relaxation characteristic time of the HO2 radical in its collisions with H2 molecules has been obtained as a result of the comparison of different experimental data on

  14. Comparisons of physical experiment and discrete element simulations of sheared granular materials in an annular shear cell

    USGS Publications Warehouse

    Ji, S.; Hanes, D.M.; Shen, H.H.

    2009-01-01

    In this study, we report a direct comparison between a physical test and a computer simulation of rapidly sheared granular materials. An annular shear cell experiment was conducted. All parameters were kept the same between the physical and the computational systems to the extent possible. Artificially softened particles were used in the simulation to reduce the computational time to a manageable level. Sensitivity study on the particle stiffness ensured such artificial modification was acceptable. In the experiment, a range of normal stress was applied to a given amount of particles sheared in an annular trough with a range of controlled shear speed. Two types of particles, glass and Delrin, were used in the experiment. Qualitatively, the required torque to shear the materials under different rotational speed compared well with those in the physical experiments for both the glass and the Delrin particles. However, the quantitative discrepancies between the measured and simulated shear stresses were nearly a factor of two. Boundary conditions, particle size distribution, particle damping and friction, including a sliding and rolling, contact force model, were examined to determine their effects on the computational results. It was found that of the above, the rolling friction between particles had the most significant effect on the macro stress level. This study shows that discrete element simulation is a viable method for engineering design for granular material systems. Particle level information is needed to properly conduct these simulations. However, not all particle level information is equally important in the study regime. Rolling friction, which is not commonly considered in many discrete element models, appears to play an important role. ?? 2009 Elsevier Ltd.

  15. [Topics in clinical thanatology. Autopathothanatobiographies, -diaries, -epistulographies in comparison with Angloamerican clinical thanatologic experiences].

    PubMed

    Jacob, H

    1990-12-01

    Extensive results of thanatologic sciences since the first decades of 20. century and multivarious practical knowledge in clinical thanatology are discussed--relating to the central problem of understanding different forms of "realisation of death". Possibilities of thanatologic information, forms of dialogue, communicative engagement and self-attitude in care-situations are critically conferred--this even in regard to mourning, grief and sorrow of the bereaved. The confrontation of thanatologic data in short-time illness until death to autopathothanatobiographic insights in long-time illness until death seems comparable in respect to relations between present clinical findings and anamnestic data. Awareness of approaching death seems not seldom due to "presentiment", averbal-communicative "preinformation" or impressions in face to progressive illness without successful therapy. Not only this is to think over in treatment and care, but also some new thanatologic experiences of the last years--for instance in respect to the question of timing, various circumstances and possible forms of informations and clearing up. Apart from individual forms of "living until death" there are certain pithy types in awareness, feeling, thinking, exposition or attitude. Some autobiographic, diaristic or epi-stulographic dates to long-time illness until death are characterized by striking limited possibilities of self-description and verbalization in situations of vital-existential distress. Silent suffering can be caused by loss of possibility in verbalization. Autothanatobiographic insights and experiences in thanatologic praxis in long-time illness until death lead to more differentiated insights than short-time illness until death--especially in respect of changing and contrary courses. Insight "evidences" of life continuities in the face of danger of death, changes in awareness of time, intensifications in intensities of perception, of feelings of the own life and changes in

  16. Gasoline surrogate modeling of gasoline ignition in a rapid compression machine and comparison to experiments

    SciTech Connect

    Mehl, M; Kukkadapu, G; Kumar, K; Sarathy, S M; Pitz, W J; Sung, S J

    2011-09-15

    The use of gasoline in homogeneous charge compression ignition engines (HCCI) and in duel fuel diesel - gasoline engines, has increased the need to understand its compression ignition processes under engine-like conditions. These processes need to be studied under well-controlled conditions in order to quantify low temperature heat release and to provide fundamental validation data for chemical kinetic models. With this in mind, an experimental campaign has been undertaken in a rapid compression machine (RCM) to measure the ignition of gasoline mixtures over a wide range of compression temperatures and for different compression pressures. By measuring the pressure history during ignition, information on the first stage ignition (when observed) and second stage ignition are captured along with information on the phasing of the heat release. Heat release processes during ignition are important because gasoline is known to exhibit low temperature heat release, intermediate temperature heat release and high temperature heat release. In an HCCI engine, the occurrence of low-temperature and intermediate-temperature heat release can be exploited to obtain higher load operation and has become a topic of much interest for engine researchers. Consequently, it is important to understand these processes under well-controlled conditions. A four-component gasoline surrogate model (including n-heptane, iso-octane, toluene, and 2-pentene) has been developed to simulate real gasolines. An appropriate surrogate mixture of the four components has been developed to simulate the specific gasoline used in the RCM experiments. This chemical kinetic surrogate model was then used to simulate the RCM experimental results for real gasoline. The experimental and modeling results covered ultra-lean to stoichiometric mixtures, compressed temperatures of 640-950 K, and compression pressures of 20 and 40 bar. The agreement between the experiments and model is encouraging in terms of first

  17. Modelling of a viscoplastic granular column collapse and comparison with experiments

    NASA Astrophysics Data System (ADS)

    Martin, Nathan; Ionescu, Ioan; Mangeney, Anne; Bouchut, François; Roche, Olivier; Farin, Maxime

    2015-04-01

    Landslides and, more generally, large scale granular flows, represent a wide variety of geophysical flows also including mud or debris flow and snow avalanches. In a continuum mechanics context, the accurate simulation of these flows strongly depends on the modelling of their rheology and their boundary conditions, namely the sliding law and processes of erosion. In particular the description of the static and of the flowing states of granular media is still an open issue. We focus here on the quantitative reproduction of laboratory experiments using a mechanical and numerical model of dry granular flows with the so-called μ(I) rheology associated to a Drucker-Prager plasticity criterion and a shear rate and pressure dependent viscosity η(||D||,p). A Coulomb type friction law is considered at the base of the flow. The modelling is achieved in a finite-element context using the software FreeFem++. The simulations are bidimensionnal and well reproduce quantitatively both the dynamical and final shapes of the deposit. The effects of the sidewalls of the experimental channel, neglected in 2D simulations, are investigated by introducing an extra term in the equations varying with the inverse of the width of the channel, providing an enhanced agreement with the experiments. The numerical results show that the flow is essentially located in a surface layer behind the front, while the whole granular material is flowing near the front where basal sliding occurs. The static/flowing interface changes as a function of space and time, in good agreement with experimental observations. The resulting dynamic viscosity varies from very small values near the free surface and near the front to 1.5Pa.s within the quasi-static zone. The results show a rather small yet computationnaly expensive difference between a constant viscosity model and a μ(I) rheology in the case of a rigid bed. This has important implication for application to real geophysical flows. The role of an erodible

  18. Simulating Thermal Explosion of Octahydrotetranitrotetrazine-based explosives: Model Comparison with Experiment

    SciTech Connect

    Yoh, J J; McClelland, M A; Maienschein, J L; Nichols, A L; Tarver, C M

    2006-02-07

    The authors compare two-dimensional model results with measurements for the thermal, chemical and mechanical behavior in a thermal explosion experiment. Confined high explosives are heated at a rate of 1 C per hour until an explosion is observed. The heating, ignition, and deflagration phases are modeled using an Arbitrarily Lagrangian-Eulerian code (ALE3D) that can handle a wide range of time scales that vary from a structural to a dynamic hydro time scale. During the pre-ignition phase, quasi-static mechanics and diffusive thermal transfer from a heat source to the HE are coupled with the finite chemical reactions that include both endothermic and exothermic processes. Once the HE ignites, a hydro dynamic calculation is performed as a burn front propagates through the HE. Two octahydrotetranitrotetrazine (HMX)-based explosives, LX-04 and LX-10, are considered, whose chemical-thermal-mechanical models are constructed based on measurements of thermal and mechanical properties along with small scale thermal explosion measurements. The present HMX modeling work shows very first violence calculations with thermal predictions associated with a confined thermal explosion test. The simulated dynamic response of HE confinement during the explosive phase is compared to measurements in larger scale thermal explosion tests. The explosion temperatures for both HE's are predicted to within 1 C. Calculated and measured wall strains provide an indication of vessel pressurization during the heating phase and violence during the explosive phase.

  19. Wave Impact on a Wall: Comparison of Experiments with Similarity Solutions

    NASA Astrophysics Data System (ADS)

    Wang, A.; Duncan, J. H.; Lathrop, D. P.

    2014-11-01

    The impact of a steep water wave on a fixed partially submerged cube is studied with experiments and theory. The temporal evolution of the water surface profile upstream of the front face of the cube in its center plane is measured with a cinematic laser-induced fluorescence technique using frame rates up to 4,500 Hz. For a small range of cube positions, the surface profiles are found to form a nearly circular arc with upward curvature between the front face of the cube and a point just downstream of the wave crest. As the crest approaches the cube, the effective radius of this portion of the profile decreases rapidly. At the same time, the portion of the profile that is upstream of the crest approaches a straight line with a downward slope of about 15°. As the wave impact continues, the circular arc shrinks to zero radius with very high acceleration and a sudden transition to a high-speed vertical jet occurs. This flow singularity is modeled with a power-law scaling in time, which is used to create a time-independent system of equations of motion. The scaled governing equations are solved numerically and the similarly scaled measured free surface shapes, are favorably compared with the solutions. The support of the Office of Naval Research is gratefully acknowledged.

  20. Comparison of abuse experiences of rural and urban African American women during perinatal period.

    PubMed

    Bhandari, Shreya; Bullock, Linda F C; Richardson, Jeanita W; Kimeto, Pamela; Campbell, Jacquelyn C; Sharps, Phyllis W

    2015-07-01

    A subsample of 12 African American women (6 urban and 6 rural) were selected from a larger longitudinal, randomized control trial, Domestic Violence Enhanced Home Visitation (DOVE-R01 900903 National Institute of Nursing Research [NINR]/National Institutes of Health [NIH]). All African American women were chosen to control for any racial- and/or race-related cultural differences that may exist among women across geographical areas. The experiences of abuse during the perinatal period are drawn from in-depth interviews conducted at five points in time during pregnancy and the post-partum period. The analysis describes three major themes that highlight the similarities and differences among rural and urban women. The main themes found were (1) types of abuse, (2) location of abuse, and (3) response to abuse. In addition, two sub-themes (a) defiance and compliance and (b) role of children were also identified. Implications for universal screening for women of reproductive age, safer gun laws, and the need for further research are discussed. PMID:25315478

  1. JT150 1/2-scale nozzle jet noise experiment and comparison with prediction

    NASA Astrophysics Data System (ADS)

    Groesbeck, D. E.; Wasserbauer, C. A.

    1983-05-01

    As part of a program to study flight effects on the exhaust noise of a full scale JT15D engine, static half scale model jet noise experiments were conducted. Acoustic data were recorded for microphone angles of 45 deg to 155 deg with jet conditions for the model scale nozzle corresponding closely to those at 55, 73 and 97 percent of corrected rated speed for the full scale engine. These data are useful for determining the relative importance of jet and core noise in the static full scale engine test data and will in turn allow for a proper evaluation of flight effects on the exhaust noise results. The model scale data are also compared with the coaxial jet noise prediction. Above 1000 Hz, the prediction is nominally 0 to 3 dB higher than the data. The arithmetic mean of the differences between the experimental OASPL and the predicted OASPL for all angles for each run ranged from 0 to -3.2 dB. The standard deviation of all the OASPL differences is 2.2 dB. The discrepancies are greatest at low primary jet velocities and appear to be due to inadequacy in the variable jet density exponent incorporated in the prediction procedure.

  2. Formal education programmes for senior house officers: comparison of experience in three hospital specialties.

    PubMed

    Flett, A; Baker, M; Williams, J

    2001-10-01

    This study was designed to compare the attendance rate of senior house officers (SHOs) in three specialties at formal educational events, examine experiences of protected time, use of educational objectives, and perceived barriers to attendance and evaluate differences found in the context of variations in training practice within each specialty. A quantitative questionnaire survey was completed by Trent region SHOs in obstetrics and gynaecology, general medicine, and accident and emergency posts. An independent researcher visited a selection of educational programme events over a two month span, recorded attendances, and administered the questionnaire. Attendance rates ranged from 40.8% of those in obstetrics and gynaecology jobs to 55.4% of those in accident and emergency jobs. The questionnaire findings found that service commitments were a major obstacle to attendance for the majority of those in obstetrics and gynaecology and general medicine jobs, while relatively few of the accident and emergency SHOs specified any barriers. SHOs in accident and emergency jobs had significantly more protected time for education and found educational objectives to be more widely used by senior staff. The findings suggest that the planned integration of formal education programmes with appropriate working pattern systems--in this case full shifts within accident and emergency departments--will result in SHOs receiving a better deal in terms of provision and structure of education.

  3. Growth of sinuous waves on thin liquid sheets: Comparison of predictions with experiments

    NASA Astrophysics Data System (ADS)

    Majumdar, Nayanika; Tirumkudulu, Mahesh S.

    2016-05-01

    A recent theory [M. S. Tirumkudulu and M. Paramati, "Stability of a moving radial liquid sheet: Time dependent equations," Phys. Fluids 25(10), 102-107 (2013)] has shown that a radially expanding liquid sheet is unstable to sinuous wave disturbances due to the thinning of the liquid sheet while ignoring the presence of a surrounding gas phase. In this work, we compare the predictions of the aforementioned theory with the measurements of Crapper et al. ["Large amplitude Kelvin-Helmholtz waves on thin liquid sheets," Proc. R. Soc. London, Ser. A 342(1629), 209-224 (1975)] who measured the amplitude and spatial growth rates of sinuous waves induced in radially expanding liquid sheets produced by fan spray nozzles. The predicted growth rates are remarkably close to the measurements over a range of forcing frequencies and amplitudes even though the experiments were performed in the presence of a surrounding gas phase. This is in contrast to large discrepancies observed by Crapper et al. when the same measurements were compared with the predictions of a spatial stability analysis for a moving liquid sheet that accounts for the inertia of the surrounding gas phase but ignores the thickness variation of the sheet.

  4. Influence of inhomogeneity of optical absorbers on optoacoustic signals: a comparison between experiment and theory

    NASA Astrophysics Data System (ADS)

    Gertsch, A. G.; Jaeger, M.; Bush, N. L.; Frenz, M.; Bamber, J. C.

    2009-02-01

    Optoacoustic (OA) imaging allows optical absorption contrast to be visualised using thermoelastically generated ultrasound. To date, optoacoustic theory has been applied to homogeneously absorbing tissue models that may describe, for example, large vessels filled with blood, where the whole target will act as a coherent source of sound. Here we describe a new model in which the optical absorbers are distributed inhomogeneously, as appropriate to describe microvasculature, or perhaps the distribution of molecularly targeted OA contrast agents inside a tumour. The degree of coherence over the resulting distributed acoustic source is influenced by parameters that describe the scale of the inhomogeneity, such as the sizes of the absorbers and the distances between them. To investigate the influence of these parameters on OA image appearance, phantoms with homogeneously and imhomogeneously absorbing regions were built and imaged. Simulations of the same situation were conducted using a time domain acoustic propagation method. Both simulations and experiments showed that introducing inhomogeneity of absorption produces more complete images of macroscopic targets than are obtained with a homogeneous absorption. Image improvement and target detectability were found to reach a maximum at an intermediate value of the length-scale of the inhomogeneity that was similar to the axial resolution of the acoustic receiver employed. As the scale of inhomogeneity became finer than this the target's detectability and appearance began to revert to that for homogeneous absorption. Further understanding of this topic is believed to be important for optimising the design of clinical optoacoustic imaging systems.

  5. Comparison of Abuse Experiences of Rural and Urban African American Women During Perinatal Period

    PubMed Central

    Bhandari, Shreya; Bullock, Linda F. C.; Richardson, Jeanita W.; Kimeto, Pamela; Campbell, Jacquelyn C.; Sharps, Phyllis W.

    2015-01-01

    A subsample of 12 African American women (6 urban and 6 rural) were selected from a larger longitudinal, randomized control trial, Domestic Violence Enhanced Home Visitation (DOVE-R01 900903 National Institute of Nursing Research [NINR]/National Institutes of Health [NIH]). All African American women were chosen to control for any racial- and/or race-related cultural differences that may exist among women across geographical areas. The experiences of abuse during the perinatal period are drawn from in-depth interviews conducted at five points in time during pregnancy and the post-partum period. The analysis describes three major themes that highlight the similarities and differences among rural and urban women. The main themes found were (1) types of abuse, (2) location of abuse, and (3) response to abuse. In addition, two sub-themes (a) defiance and compliance and (b) role of children were also identified. Implications for universal screening for women of reproductive age, safer gun laws, and the need for further research are discussed. PMID:25315478

  6. The probability of evolutionary rescue: towards a quantitative comparison between theory and evolution experiments.

    PubMed

    Martin, Guillaume; Aguilée, Robin; Ramsayer, Johan; Kaltz, Oliver; Ronce, Ophélie

    2013-01-19

    Evolutionary rescue occurs when a population genetically adapts to a new stressful environment that would otherwise cause its extinction. Forecasting the probability of persistence under stress, including emergence of drug resistance as a special case of interest, requires experimentally validated quantitative predictions. Here, we propose general analytical predictions, based on diffusion approximations, for the probability of evolutionary rescue. We assume a narrow genetic basis for adaptation to stress, as is often the case for drug resistance. First, we extend the rescue model of Orr & Unckless (Am. Nat. 2008 172, 160-169) to a broader demographic and genetic context, allowing the model to apply to empirical systems with variation among mutation effects on demography, overlapping generations and bottlenecks, all common features of microbial populations. Second, we confront our predictions of rescue probability with two datasets from experiments with Saccharomyces cerevisiae (yeast) and Pseudomonas fluorescens (bacterium). The tests show the qualitative agreement between the model and observed patterns, and illustrate how biologically relevant quantities, such as the per capita rate of rescue, can be estimated from fits of empirical data. Finally, we use the results of the model to suggest further, more quantitative, tests of evolutionary rescue theory.

  7. Capillary trapping mechanism in strongly water wet systems: Comparison between experiment and percolation theory

    NASA Astrophysics Data System (ADS)

    Geistlinger, Helmut; Mohammadian, Sadjad

    2015-05-01

    To understand capillary trapping mechanism, we conduct a real Monte-Carlo experiment by using packed glass beads with nearly the same pore size distribution, but different stochastic realizations. We study gas phase trapping during imbibition for capillary numbers from 2 × 10-7 to 10-6 using X-ray micro tomography and compare the experimental results with predictions from percolation theory. We found excellent agreement. Percolation theory explains (i) that the capillary desaturation curves are not dependent on flow rate, (ii) the linear dependence of the total gas surface on gas saturation that is a direct consequence of the linear relationship between cluster surface area and cluster volume, which is a prediction from percolation theory for large finite clusters, (iii) the power-like cluster size distribution with an exponent τexp = 2.15 that only deviates by 2% from the theoretical one (τtheor = 2.19), and (iv) that the maximal z-extension of trapped large gas cluster is described by the cut-off correlation length ξB (B - bond number).

  8. Preparing beginning reading teachers: An experimental comparison of initial early literacy field experiences

    PubMed Central

    Lake, Vickie E.; Greulich, Luana; Folsom, Jessica S.; Guidry, Lisa

    2012-01-01

    This randomized-control trial examined the learning of preservice teachers taking an initial Early Literacy course in an early childhood education program and of the kindergarten or first grade students they tutored in their field experience. Preservice teachers were randomly assigned to one of two tutoring programs: Book Buddies and Tutor Assisted Intensive Learning Strategies (TAILS), which provided identical meaning-focused instruction (shared book reading), but differed in the presentation of code-focused skills. TAILS used explicit, scripted lessons, and the Book Buddies required that code-focused instruction take place during shared book reading. Our research goal was to understand which tutoring program would be most effective in improving knowledge about reading, lead to broad and deep language and preparedness of the novice preservice teachers, and yield the most successful student reading outcomes. Findings indicate that all pre-service teachers demonstrated similar gains in knowledge, but preservice teachers in the TAILS program demonstrated broader and deeper application of knowledge and higher self-ratings of preparedness to teach reading. Students in both conditions made similar comprehension gains, but students tutored with TAILS showed significantly stronger decoding gains. PMID:24204096

  9. Preparing beginning reading teachers: An experimental comparison of initial early literacy field experiences.

    PubMed

    Al Otaiba, Stephanie; Lake, Vickie E; Greulich, Luana; Folsom, Jessica S; Guidry, Lisa

    2012-01-01

    This randomized-control trial examined the learning of preservice teachers taking an initial Early Literacy course in an early childhood education program and of the kindergarten or first grade students they tutored in their field experience. Preservice teachers were randomly assigned to one of two tutoring programs: Book Buddies and Tutor Assisted Intensive Learning Strategies (TAILS), which provided identical meaning-focused instruction (shared book reading), but differed in the presentation of code-focused skills. TAILS used explicit, scripted lessons, and the Book Buddies required that code-focused instruction take place during shared book reading. Our research goal was to understand which tutoring program would be most effective in improving knowledge about reading, lead to broad and deep language and preparedness of the novice preservice teachers, and yield the most successful student reading outcomes. Findings indicate that all pre-service teachers demonstrated similar gains in knowledge, but preservice teachers in the TAILS program demonstrated broader and deeper application of knowledge and higher self-ratings of preparedness to teach reading. Students in both conditions made similar comprehension gains, but students tutored with TAILS showed significantly stronger decoding gains.

  10. Student Award Finalist - Simulation of the reignition of atmospheric pressure air discharges behind dielectric obstacles: comparison with experiments

    NASA Astrophysics Data System (ADS)

    Pechereau, Francois; Bourdon, Anne

    2013-09-01

    In recent years, experimental studies on plasma assisted catalysis for flue gas treatment have shown a significant reduction of pollutants at a low energetic cost. Catalyst supports are either random or organized two phase media such as pellets, monoliths or porous media. Then, in plasma reactors, atmospheric pressure discharges have to interact with many obstacles and to propagate in microcavities and pores. To better understand the discharge dynamics in these complex structures, experiments have been carried out at LPGP (Orsay, France) in a point-to-plane geometry with a dielectric plane obstacle placed in the discharge path. In this work, we have carried out discharge simulations in the experimental geometry. We have compared the dynamics of the discharge ignited at the point and its impact on the dielectric surface. Then, we have compared the conditions of a discharge reignition behind the dielectric obstacle. A good qualitative agreement with experiments has been obtained but to improve the quantitative comparison, we have carried out a detailed parametric numerical study. In this work, we will focus on the influence of the level of seed charges on the discharge reignition and discuss several physical processes that could have an impact on the level of seed charges. ALVEOPLAS project (Grant No. ANR-08-BLAN-0159-01).

  11. Comparison of fast ion confinement during on-axis and off-axis neutral beam experiments on NSTX-U

    NASA Astrophysics Data System (ADS)

    Liu, D.; Heidbrink, W. W.; Hao, G. Z.; Podesta, M.; Darrow, D. S.; Fredrickson, E. D.; Medley, S. S.

    2015-11-01

    A second and more tangential neutral beam line is a major upgrade component of the National Spherical Torus Experiment - Upgrade (NSTX-U) with the purpose of improving neutral beam current drive efficiency and providing more flexibility in current/pressure profile control. Good fast ion confinement is essential to achieve the anticipated improvements in performance. In a planed ``sanity check'' experiment, various short and long (relative to fast ion slowing-down time) neutral beam (NB) pulses with different source mixes will be injected into quiescent L-mode plasmas to characterize the fast ion confinement and distribution function produced by the new and the existing NBI lines. The neutron rate decay after the turn-off of short NB pulses will be used to estimate the fast ion confinement time and to investigate its dependence on NB source/geometry, injection energy, and plasma current. The newly installed Solid State Neutral Particle Analyzer (SSNPA) and Fast-Ion D-Alapha (FIDA) diagnostics will be described and will be used to measure fast ion slowing-down distribution function and spatial profile during the injection of relatively long NB pulses. Fast ion prompt losses will be monitored with a scintillator Fast Lost Ion Probe (sFLIP) diagnostic. The experimental techniques, measurements of fast ion confinement time and distribution function, and comparisons with classical predictions from NUBEAM modeling will be presented in detail. Work supported by US DOE.

  12. Rate Coefficient for the (4)Heμ + CH4 Reaction at 500 K: Comparison between Theory and Experiment.

    PubMed

    Arseneau, Donald J; Fleming, Donald G; Li, Yongle; Li, Jun; Suleimanov, Yury V; Guo, Hua

    2016-03-01

    The rate constant for the H atom abstraction reaction from methane by the muonic helium atom, Heμ + CH4 → HeμH + CH3, is reported at 500 K and compared with theory, providing an important test of both the potential energy surface (PES) and reaction rate theory for the prototypical polyatomic CH5 reaction system. The theory used to characterize this reaction includes both variational transition-state (CVT/μOMT) theory (VTST) and ring polymer molecular dynamics (RPMD) calculations on a recently developed PES, which are compared as well with earlier calculations on different PESs for the H, D, and Mu + CH4 reactions, the latter, in particular, providing for a variation in atomic mass by a factor of 36. Though rigorous quantum calculations have been carried out for the H + CH4 reaction, these have not yet been extended to the isotopologues of this reaction (in contrast to H3), so it is important to provide tests of less rigorous theories in comparison with kinetic isotope effects measured by experiment. In this regard, the agreement between the VTST and RPMD calculations and experiment for the rate constant of the Heμ + CH4 reaction at 500 K is excellent, within 10% in both cases, which overlaps with experimental error.

  13. Kinetic simulation of direct-drive capsule implosions and its comparison with experiments and radiation hydrodynamic simulation

    NASA Astrophysics Data System (ADS)

    Kwan, Thomas; Le, Ari; Schmitt, Mark; Herrmann, Hans; Batha, Steve

    2015-11-01

    We have carried out simulations of direct-drive capsule implosion experiments conducted on Omega laser facility at the Laboratory of Laser energetics of the University of Rochester. The capsules had a glass shell (SiO2) with D, T, He-3 fills at various proportions. One-dimensional radiation hydrodynamic calculations and kinetic particle/hybrid simulations with LSP were carried out for the post-shot analysis to compare neutron yield, yield ratio, and shell convergence in assessing the effects of plasma kinetic effects. The LSP simulations were initiated with the output from the rad-hydro simulations at the end of the laser-drive. The electrons are treated as a fluid while all the ion species by the kinetic PIC technique. Our LSP simulations clearly showed species separation between the deuterons, tritons and He-3 during the implosion but significantly less after the compression. The neutron yield, gamma bang-time and -width from the LSP simulations compared favorably with experiments. Detail comparison among the kinetic simulations, rad-hydro simulations, and experimental results will be presented. Work performed under the auspices of the US Department of Energy by Los Alamos National Laboratory under Contract No. W-7405-ENG-36.

  14. Low-energy physical properties of high- Tc superconducting Cu oxides: A comparison between the resonating valence bond and experiments

    NASA Astrophysics Data System (ADS)

    Yang, Kai-Yu; Shih, C. T.; Chou, C. P.; Huang, S. M.; Lee, T. K.; Xiang, T.; Zhang, F. C.

    2006-06-01

    In a recent review by Anderson and co-workers, it was pointed out that an early resonating valence bond (RVB) theory is able to explain a number of unusual properties of high-temperature superconducting (SC) Cu oxides. Here we extend previous calculations to study more systematically the low-energy physical properties of the plain vanilla d -wave RVB state, and to compare the results with the available experiments. We use a renormalized mean-field theory combined with variational Monte Carlo and power Lanczos methods to study the RVB state of an extended t-J model in a square lattice with parameters suitable for the hole-doped Cu oxides. The physical observable quantities we study include the specific heat, the linear residual thermal conductivity, the in-plane magnetic penetration depth, the quasiparticle energy at the antinode (π,0) , the superconducting energy gap, the quasiparticle spectra, and the Drude weights. The traits of nodes (including kF , the Fermi velocity vF , and the velocity along Fermi surface v2 ), and the SC order parameter are studied. Comparisons of the theory and the experiments in cuprates show an overall qualitative agreement, especially on their doping dependences.

  15. Comparisons among three types of generalist physicians: Personal characteristics, medical school experiences, financial aid, and other factors influencing career choice.

    PubMed

    Xu, G; Veloski, J J; Barzansky, B; Hojat, M; Diamond, J; Silenzio, V M

    1996-01-01

    A national survey of family physicians, general internists, and general pediatricians was conducted in the US to examine differences among the three groups of generalists physicians, with particular regard to the factors influencing their choice of generalist career. Family physicians were more likely to have made their career decision before medical school, and were more likely to have come from inner-city or rural areas. Personal values and early role models play a very important role in influencing their career choice. In comparison, a higher proportion of general internists had financial aid service obligations and their choice of the specialty was least influenced by personal values. General pediatricians had more clinical experiences either in primary care or with underserved populations, and they regarded medical school experiences as more important in influencing their specialty choice than did the other two groups. Admission committees may use these specialty-related factors to develop strategies to attract students into each type of generalist career. PMID:24179019

  16. Simulating thermal explosion of RDX-based explosives: Model comparison with experiment

    SciTech Connect

    Yoh, J J; McClelland, M A; Maienschein, J L; Wardell, J F; Tarver, C M

    2004-10-11

    We compare two-dimensional model results with measurements for the thermal, chemical and mechanical behavior in a thermal explosion experiment. Confined high explosives are heated at a rate of 1 C per hour until an explosion is observed. The heating, ignition, and deflagration phases are modeled using an Arbitrarily Lagrangian-Eulerian code (ALE3D) that can handle a wide range of time scales that vary from a structural to a dynamic hydro time scale. During the pre-ignition phase, quasi-static mechanics and diffusive thermal transfer from a heat source to the HE are coupled with the finite chemical reactions that include both endothermic and exothermic processes. Once the HE ignites, a hydro dynamic calculation is performed as a burn front propagates through the HE. Two RDX-based explosives, C-4 and PBXN-109, are considered, whose chemical-thermal-mechanical models are constructed based on measurements of thermal and mechanical properties along with small scale thermal explosion measurements. The simulated dynamic response of HE confinement during the explosive phase is compared to measurements in large scale thermal explosion tests. The explosion temperatures for both HE's are predicted to within 5 C. Calculated and measured wall strains provide an indication of vessel pressurization during the heating phase and violence during the explosive phase. During the heating phase, simulated wall strains provide only an approximate representation of measured values indicating a better numerical treatment is needed to provide accurate results. The results also show that more numerical accuracy is needed for vessels with lesser confinement strength. For PBXN-109, the measured wall strains during the explosion are well represented by the ALE3D calculations.

  17. Comparison of Aerosol Single Scattering Albedos Derived By Diverse Techniques in Two North Atlantic Experiments

    NASA Technical Reports Server (NTRS)

    Russell, P. B.; Redemann, J.; Schmid, B.; Bergstrom, R. W.; Livingston, J. M.; McIntosh, D. M.; Hartley, S.; Hobbs, P. V.; Quinn, P. K.; Carrico, C. M.; Hipskind, R. Stephen (Technical Monitor)

    2000-01-01

    Aerosol single scattering albedo w (the ratio of scattering to extinction) is important in determining aerosol climatic effects, in explaining relationships between calculated and measured radiative fluxes, and in retrieving aerosol optical depths from satellite radiances. Recently, two experiments in the North Atlantic region, TARFOX and ACE-2, determined aerosol w by a variety of techniques. The techniques included fitting of calculated to measured fluxes; retrievals of w from skylight radiances; best fits of complex refractive index to profiles of backscatter, extinction, and size distribution; and in situ measurements of scattering and absorption at the surface and aloft. Both TARFOX and ACE-2 found a fairly wide range of values for w at midvisible wavelengths, with 0.85 less than wmidvis less than 0.99 for the marine aerosol impacted by continental pollution. Frequency distributions of w could usually be approximated by lognormals in wmax-w, with some occurrence of bimodality, suggesting the influence of different aerosol sources or processing. In both TARFOX and ACE-2, closure tests between measured and calculated radiative fluxes yielded best-fit values of wmidvis of 0.90+/-0.04 for the polluted boundary layer. Although these results have the virtue of describing the column aerosol unperturbed by sampling, they are subject to questions about representativeness and possible artifacts (e.g., unknown gas absorption). The other techniques gave larger values for wmidvis for the polluted boundary layer, with a typical result of wmidvis = 0.95+/-0.04, Current uncertainties in vv are large in terms of climate effects. More tests are needed of the consistency among different methods and of humidification effects on w.

  18. Comparisons of Box Model Calculations and Measurements of Formaldehyde from the 1997 North Atlantic Regional Experiment

    SciTech Connect

    Frost, G. J.; Fried, Alan; Lee, Y.- N.; Wert, B.; Henry, B.; Drummond, J. R.; Evans, M. J.; Fehsenfeld, Fred C.; Goldan, P. D.; Holloway, J. S.; Hubler, Gerhard F.; Jakoubek, R.; Jobson, B Tom T.; Knapp, K.; Kuster, W. C.; Roberts, J.; Rudolph, Jochen; Ryerson, T. B.; Stohl, A.; Stroud, C.; Sueper, D. T.; Trainer, Michael; Williams, J.

    2002-04-18

    Formaldehyde (CH2O) measurements from two independent instruments are compared with photochemical box model calculations. The measurements were made on the National Oceanic and Atmospheric Administration P-3 aircraft as part of the 1997 North Atlantic Regional Experiment (NARE 97). The data set considered here consists of air masses sampled between 0 and 8 km over the North Atlantic Ocean which do not show recent influence from emissions or transport. These air masses therefore should be in photochemical steady state with respect to CH2O when constrained by the other P-3 measurements, and methane oxidation was expected to be the predominant source of CH2O in these air masses. For this data set both instruments measured identical CH2O concentrations to within 40 parts per trillion by volume (pptv) on average over the 0–800 pptv range, although differences larger than the combined 2s total uncertainty estimates were observed between the two instruments in 11% of the data. Both instruments produced higher CH2O concentrations than the model in more than 90% of this data set, with a median measured-modeled [CH2O] difference of 0.13 or 0.18 ppbv (depending on the instrument), or about a factor of 2. Such large differences cannot be accounted for by varying model input parameters within their respective uncertainty ranges. After examining the possible reasons for the model-measurement discrepancy, we conclude that there are probably one or more additional unknown sources of CH2O in the North Atlantic troposphere.

  19. A biomechanical comparison of composite femurs and cadaver femurs used in experiments on operated hip fractures.

    PubMed

    Basso, Trude; Klaksvik, Jomar; Syversen, Unni; Foss, Olav A

    2014-12-18

    Fourth generation composite femurs (4GCFs, models #3406 and #3403) simulate femurs of males <80 years with good bone quality. Since most hip fractures occur in old women with fragile bones, concern is raised regarding the use of standard 4GCFs in biomechanical experiments. In this study the stability of hip fracture fixations in 4GCFs was compared to human cadaver femurs (HCFs) selected to represent patients with hip fractures. Ten 4GCFs (Sawbones, Pacific Research Laboratories, Inc., Vashon, WA, USA) were compared to 24 HCFs from seven females and five males >60 years. Proximal femur anthropometric measurements were noted. Strain gauge rosettes were attached and femurs were mounted in a hip simulator applying a combined subject-specific axial load and torque. Baseline measurements of resistance to deformation were recorded. Standardized femoral neck fractures were surgically stabilized before the constructs were subjected to 20,000 load-cycles. An optical motion tracking system measured relative movements. Median (95% CI) head fragment migration was 0.8mm (0.4 to 1.1) in the 4GCF group versus 2.2mm (1.5 to 4.6) in the cadaver group (p=0.001). This difference in fracture stability could not be explained by observed differences in femoral anthropometry or potential overloading of 4GCFs. 4GCFs failed with fracture-patterns different from those observed in cadavers. To conclude, standard 4GCFs provide unrealistically stable bone-implant constructs and fail with fractures not observed in cadavers. Until a validated osteopenic or osteoporotic composite femur model is provided, standard 4GCFs should only be used when representing the biomechanical properties of young healthy femurs.

  20. Simulating thermal explosion of cyclotrimethylenetrinitramine-based explosives: Model comparison with experiment

    NASA Astrophysics Data System (ADS)

    Yoh, Jack J.; McClelland, Matthew A.; Maienschein, Jon L.; Wardell, Jeffrey F.; Tarver, Craig M.

    2005-04-01

    We compare two-dimensional model results with measurements for the thermal, chemical, and mechanical behavior in a thermal explosion experiment. Confined high explosives (HEs) are heated at a rate of 1°C/h until an explosion is observed. The heating, ignition, and deflagration phases are modeled using an Arbitrarily Lagrangian-Eulerian code (ALE3D) that can handle a wide range of time scales that vary from a structural to a dynamic hydrotime scale. During the preignition phase, quasistatic mechanics and diffusive thermal transfer from a heat source to the HE are coupled with the finite chemical reactions that include both endothermic and exothermic processes. Once the HE ignites, a hydrodynamic calculation is performed as a burn front propagates through the HE. Two cyclotrimethylenetrinitramine-based explosives, C-4 and PBXN-109, are considered, whose chemical-thermal-mechanical models are constructed based on measurements of thermal and mechanical properties along with small scale thermal explosion measurements. The simulated dynamic response of HE confinement during the explosive phase is compared to measurements in larger scale thermal explosion tests. The explosion temperatures for both HEs are predicted to within 5°C. Calculated and measured wall strains provide an indication of vessel pressurization during the heating phase and violence during the explosive phase. During the heating phase, simulated wall strains provide only an approximate representation of measured values indicating a better numerical treatment is needed to provide accurate results. The results also show that more numerical accuracy is needed for vessels with lesser confinement strength. For PBXN-109, the measured wall strains during the explosion are well represented by the ALE3D calculations.

  1. Bacterial Chemotaxis in Porous Media: Theory Derivation and Comparison with Experiments

    NASA Astrophysics Data System (ADS)

    Valdés-Parada, Francisco J.; Porter, Mark L.; Wood, Brian D.

    2010-12-01

    Chemotaxis is the movement of organisms toward or away from the concentration gradient of a chemical species. Microbial chemotaxis has been shown to significantly increase contaminant degradation in subsurface environments with respect to traditional methods such as pump-and-treat. This type of transport phenomena often involves diffusion and convection along several scales. In this work we use the method of volume averaging to upscale the governing equations for in situ bioremediation by bacterial chemotaxis. The results are effective medium mass balance equations for both the bacteria and the chemical attractant. These equations are expressed in terms of average transport coefficients, which can be computed from the solution of the associated closure problems. For the bacteria, we introduce a total motility tensor and a total velocity vector, which are dependent upon the porous medium geometry, the fluid flow and the macroscale concentration and flux of the attractant. An attractive feature of this approach is that the transport coefficients can be computed a priori from performing experiments since they do not involve the use of adjustable coefficients. In addition, the necessary scaling laws, in terms of length-scale constraints and assumptions, which bound the applicability of the model are explicitly stated. The model was validated by comparing the transverse bacterial concentration with previously reported experimental measurements for E. coli HCB1 in a T-sensor. The results exhibited a maximum deviation of approximately 10% (in terms of the mean absolute error) with experimental data for several flow rates. These results suggest that the predictive multiscale approach presented here is reliable for modeling chemotaxis in porous media.

  2. Comparison of prototype and laboratory experiments on MOMA GCMS: results from the AMASE11 campaign.

    PubMed

    Siljeström, Sandra; Freissinet, Caroline; Goesmann, Fred; Steininger, Harald; Goetz, Walter; Steele, Andrew; Amundsen, Hans

    2014-09-01

    The characterization of any organic molecules on Mars is a top-priority objective for the ExoMars European Space Agency-Russian Federal Space Agency joint mission. The main instrument for organic analysis on the ExoMars rover is the Mars Organic Molecule Analyzer (MOMA). In preparation for the upcoming mission in 2018, different Mars analog samples are studied with MOMA and include samples collected during the Arctic Mars Analog Svalbard Expedition (AMASE) to Svalbard, Norway. In this paper, we present results obtained from two different Mars analog sites visited during AMASE11, Colletthøgda and Botniahalvøya. Measurements were performed on the samples during AMASE11 with a MOMA gas chromatograph (GC) prototype connected to a commercial mass spectrometer (MS) and later in home institutions with commercial pyrolysis-GCMS instruments. In addition, derivatization experiments were performed on the samples during AMASE11 and in the laboratory. Three different samples were studied from the Colletthøgda that included one evaporite and two carbonate-bearing samples. Only a single sample was studied from the Botniahalvøya site, a weathered basalt covered by a shiny surface consisting of manganese and iron oxides. Organic molecules were detected in all four samples and included aromatics, long-chained hydrocarbons, amino acids, nucleobases, sugars, and carboxylic acids. Both pyrolysis and derivatization indicated the presence of extinct biota by the detection of carboxylic acids in the samples from Colletthøgda, while the presence of amino acids, nucleobases, carboxylic acids, and sugars indicated an active biota in the sample from Botniahalvøya. The results obtained with the prototype flight model in the field coupled with repeat measurements with commercial instruments within the laboratory were reassuringly similar. This demonstrates the performance of the MOMA instrument and validates that the instrument will aid researchers in their efforts to answer fundamental

  3. Comparison of prototype and laboratory experiments on MOMA GCMS: results from the AMASE11 campaign.

    PubMed

    Siljeström, Sandra; Freissinet, Caroline; Goesmann, Fred; Steininger, Harald; Goetz, Walter; Steele, Andrew; Amundsen, Hans

    2014-09-01

    The characterization of any organic molecules on Mars is a top-priority objective for the ExoMars European Space Agency-Russian Federal Space Agency joint mission. The main instrument for organic analysis on the ExoMars rover is the Mars Organic Molecule Analyzer (MOMA). In preparation for the upcoming mission in 2018, different Mars analog samples are studied with MOMA and include samples collected during the Arctic Mars Analog Svalbard Expedition (AMASE) to Svalbard, Norway. In this paper, we present results obtained from two different Mars analog sites visited during AMASE11, Colletthøgda and Botniahalvøya. Measurements were performed on the samples during AMASE11 with a MOMA gas chromatograph (GC) prototype connected to a commercial mass spectrometer (MS) and later in home institutions with commercial pyrolysis-GCMS instruments. In addition, derivatization experiments were performed on the samples during AMASE11 and in the laboratory. Three different samples were studied from the Colletthøgda that included one evaporite and two carbonate-bearing samples. Only a single sample was studied from the Botniahalvøya site, a weathered basalt covered by a shiny surface consisting of manganese and iron oxides. Organic molecules were detected in all four samples and included aromatics, long-chained hydrocarbons, amino acids, nucleobases, sugars, and carboxylic acids. Both pyrolysis and derivatization indicated the presence of extinct biota by the detection of carboxylic acids in the samples from Colletthøgda, while the presence of amino acids, nucleobases, carboxylic acids, and sugars indicated an active biota in the sample from Botniahalvøya. The results obtained with the prototype flight model in the field coupled with repeat measurements with commercial instruments within the laboratory were reassuringly similar. This demonstrates the performance of the MOMA instrument and validates that the instrument will aid researchers in their efforts to answer fundamental

  4. Design of a Laboratory Hall Thruster with Magnetically Shielded Channel Walls, Phase III: Comparison of Theory with Experiment

    NASA Technical Reports Server (NTRS)

    Mikellides, Ioannis G.; Katz, Ira; Hofer, Richard R.; Goebel, Dan M.

    2012-01-01

    A proof-of-principle effort to demonstrate a technique by which erosion of the acceleration channel in Hall thrusters of the magnetic-layer type can be eliminated has been completed. The first principles of the technique, now known as "magnetic shielding," were derived based on the findings of numerical simulations in 2-D axisymmetric geometry. The simulations, in turn, guided the modification of an existing 6-kW laboratory Hall thruster. This magnetically shielded (MS) thruster was then built and tested. Because neither theory nor experiment alone can validate fully the first principles of the technique, the objective of the 2-yr effort was twofold: (1) to demonstrate in the laboratory that the erosion rates can be reduced by >order of magnitude, and (2) to demonstrate that the near-wall plasma properties can be altered according to the theoretical predictions. This paper concludes the demonstration of magnetic shielding by reporting on a wide range of comparisons between results from numerical simulations and laboratory diagnostics. Collectively, we find that the comparisons validate the theory. Near the walls of the MS thruster, theory and experiment agree: (1) the plasma potential has been sustained at values near the discharge voltage, and (2) the electron temperature has been lowered by at least 2.5-3 times compared to the unshielded (US) thruster. Also, based on carbon deposition measurements, the erosion rates at the inner and outer walls of the MS thruster are found to be lower by at least 2300 and 1875 times, respectively. Erosion was so low along these walls that the rates were below the resolution of the profilometer. Using a sputtering yield model with an energy threshold of 25 V, the simulations predict a reduction of 600 at the MS inner wall. At the outer wall ion energies are computed to be below 25 V, for which case we set the erosion to zero in the simulations. When a 50-V threshold is used the computed ion energies are below the threshold at both

  5. Heating mode transition in capacitively coupled CF4 discharges: comparison of experiments with simulations

    NASA Astrophysics Data System (ADS)

    Liu, Gang-Hu; Liu, Yong-Xin; Wen, De-Qi; Wang, You-Nian

    2015-06-01

    The electron heating mode transitions in capacitively coupled CF4 discharges were studied by synergistically using two diagnostic methods in combination with Particle-in-Cell/Monte Carlo collision (PIC/MCC) simulations. Based on the method of phase resolved optical emission spectroscopy of trace rare gas, the spatiotemporal evolutions of energetic electrons were presented. The time-average electron density at the discharge center was measured by using a hairpin probe. All the experimental results were compared with those obtained from PIC/MCC simulations. Two different electron heating modes were observed depending on the discharge conditions: (1) the α mode (or electropositive mode), in which the electron heating maximum occurs near the sheath boundary, dominated by the sheath electric field during its expansion phase, (2) the drift-ambipolar (DA) mode (or electronegative mode), in which the electron heating maxima occur inside the entire bulk plasma and near the collapsing sheath edge, dominated by the drift field inside the bulk and the ambipolar fields near the collapsing sheath edge, respectively. The transitions between the two modes were presented when changing the rf power, working pressure and driving frequency. By increasing the power, the heating mode experiences a transition from DA to α mode. This is ascribed to the fact that at high powers, the sheath heating is enhanced, leading to a drastic decrease in the electronegativity, and consequently the DA electric field is significantly reduced. By increasing the pressure, a heating mode transition from a pure α mode, then a combination of α and DA modes, finally into a DA mode is induced. We found that the mode transition is much more sensitive to the change of working pressure than that of rf power. When increasing the pressure, there is an evident enhancement in the electron attachment, which can generate the negative ions and deplete the electrons, resulting in a higher electronegativity as well as

  6. Comparison of Calculated and Measured Neutron Fluence in Fuel/Cladding Irradiation Experiments in HFIR

    SciTech Connect

    Ellis, Ronald James

    2011-01-01

    A recently-designed thermal neutron irradiation facility has been used for a first series of irradiations of PWR fuel pellets in the high flux isotope reactor (HFIR) at Oak Ridge National Laboratory. Since June 2010, irradiations of PWR fuel pellets made of UN or UO{sub 2}, clad in SiC, have been ongoing in the outer small VXF sites in the beryllium reflector region of the HFIR, as seen in Fig. 1. HFIR is a versatile, 85 MW isotope production and test reactor with the capability and facilities for performing a wide variety of irradiation experiments. HFIR is a beryllium-reflected, light-water-cooled and -moderated, flux-trap type reactor that uses highly enriched (in {sup 235}U) uranium (HEU) as the fuel. The reactor core consists of a series of concentric annular regions, each about 2 ft (0.61 m) high. A 5-in. (12.70-cm)-diam hole, referred to as the flux trap, forms the center of the core. The fuel region is composed of two concentric fuel elements made up of many involute-shaped fuel plates: an inner element that contains 171 fuel plates, and an outer element that contains 369 fuel plates. The fuel plates are curved in the shape of an involute, which provides constant coolant channel width between plates. The fuel (U{sub 3}O{sub 8}-Al cermet) is nonuniformly distributed along the arc of the involute to minimize the radial peak-to-average power density ratio. A burnable poison (B{sub 4}C) is included in the inner fuel element primarily to reduce the negative reactivity requirements of the reactor control plates. A typical HEU core loading in HFIR is 9.4 kg of {sup 235}U and 2.8 g of {sup 10}B. The thermal neutron flux in the flux trap region can exceed 2.5 x 10{sup 15} n/cm{sup 2} {center_dot} s while the fast flux in this region exceeds 1 x 10{sup 15} n/cm{sup 2} {center_dot} s. The inner and outer fuel elements are in turn surrounded by a concentric ring of beryllium reflector approximately 1 ft (0.30 m) thick. The beryllium reflector consists of three regions

  7. Laboratory experiments for inter-comparison of three volume scattering meters to measure angular scattering properties of hydrosols.

    PubMed

    Harmel, T; Hieronymi, M; Slade, W; Röttgers, R; Roullier, F; Chami, M

    2016-01-25

    Measurements of the volume scattering function (VSF) of hydrosols is of primary importance to investigate the interaction of light with hydrosols and to further interpret in situ and remote sensing data of ocean color. In this paper, a laboratory inter-comparison experiment of three recently developed VSF meters that are able to measure the scattered light for a wide range of scattering angle at 515 nm wavelength is performed using phytoplankton cultures and mineral-like hydrosols. A rigorous measurement protocol was employed to ensure good quality data. In particular, the protocol enabled removing the influence of bacteria on the hydrosols within the sample. The differences in the VSF measurements between the instruments vary from 10 to 25% depending on the composition of the hydrosols. The analysis of the angular features of the VSF revealed a sharp increase of the VSF beyond the scattering angle of 150° for some phytoplankton species. Such behavior is observed for two of the three VSF meters, thus suggesting that it is not due to instrumental artifacts but more likely to phytoplankton optical properties themselves. Moreover, comparisons with currently used theoretical phase functions show that the models are not able to reproduce satisfactorily the directional patterns in the backscattering region. This study suggests that a better modelling of the VSF shape of phytoplankton at high scattering angles is required to correctly represent the angular shape of the VSF in the backscattering hemisphere. Tabulated values of the measured phase functions are provided for scattering angles from 0.1 to 175°.

  8. Simulations of inorganic-bioorganic interfaces to discover new materials: insights, comparisons to experiment, challenges, and opportunities.

    PubMed

    Heinz, Hendrik; Ramezani-Dakhel, Hadi

    2016-01-21

    Natural and man-made materials often rely on functional interfaces between inorganic and organic compounds. Examples include skeletal tissues and biominerals, drug delivery systems, catalysts, sensors, separation media, energy conversion devices, and polymer nanocomposites. Current laboratory techniques are limited to monitor and manipulate assembly on the 1 to 100 nm scale, time-consuming, and costly. Computational methods have become increasingly reliable to understand materials assembly and performance. This review explores the merit of simulations in comparison to experiment at the 1 to 100 nm scale, including connections to smaller length scales of quantum mechanics and larger length scales of coarse-grain models. First, current simulation methods, advances in the understanding of chemical bonding, in the development of force fields, and in the development of chemically realistic models are described. Then, the recognition mechanisms of biomolecules on nanostructured metals, semimetals, oxides, phosphates, carbonates, sulfides, and other inorganic materials are explained, including extensive comparisons between modeling and laboratory measurements. Depending on the substrate, the role of soft epitaxial binding mechanisms, ion pairing, hydrogen bonds, hydrophobic interactions, and conformation effects is described. Applications of the knowledge from simulation to predict binding of ligands and drug molecules to the inorganic surfaces, crystal growth and shape development, catalyst performance, as well as electrical properties at interfaces are examined. The quality of estimates from molecular dynamics and Monte Carlo simulations is validated in comparison to measurements and design rules described where available. The review further describes applications of simulation methods to polymer composite materials, surface modification of nanofillers, and interfacial interactions in building materials. The complexity of functional multiphase materials creates

  9. Comparison of silver, cesium, and strontium release predictions using PARFUME with results from the AGR-1 irradiation experiment

    SciTech Connect

    Collin, Blaise P.; Petti, David A.; Demkowicz, Paul A.; Maki, John T.

    2015-08-22

    The PARFUME (PARticle FUel ModEl) code was used to predict the release of fission products silver, cesium, and strontium from tristructural isotropic coated fuel particles and compacts during the first irradiation experiment (AGR-1) of the Advanced Gas Reactor Fuel Development and Qualification program. The PARFUME model for the AGR-1 experiment used the fuel compact volume average temperature for each of the 620 days of irradiation to calculate the release of silver, cesium, and strontium from a representative particle for a select number of AGR-1 compacts. Post-irradiation examination measurements provided data on release of these fission products from fuel compacts and fuel particles, and retention of silver in the compacts outside of the silicon carbide (SiC) layer. PARFUME-predicted fractional release of silver, cesium, and strontium was determined and compared to the PIE measurements. For silver, comparisons show a trend of over-prediction at low burnup and under-prediction at high burnup. PARFUME has limitations in the modeling of the temporal and spatial distributions of the temperature and burnup across the compacts, which affects the accuracy of its predictions. Nevertheless, the comparisons on silver release lie in the same order of magnitude. Results show an overall over-prediction of the fractional release of cesium by PARFUME. For particles with failed SiC layers, the over-prediction is by a factor of up to 3, corresponding to a potential over-estimation of the diffusivity in uranium oxycarbide (UCO) by a factor of up to 250. For intact particles, whose release is much lower, the over-prediction is by a factor of up to 100, which could be attributed to an over-estimated diffusivity in SiC by about 40% on average. The release of strontium from intact particles is also over-predicted by PARFUME, which also points towards an over-estimated diffusivity of strontium in either SiC or UCO, or possibly both. The measured strontium fractional release from

  10. Comparison of silver, cesium, and strontium release predictions using PARFUME with results from the AGR-1 irradiation experiment

    DOE PAGES

    Collin, Blaise P.; Petti, David A.; Demkowicz, Paul A.; Maki, John T.

    2015-08-22

    The PARFUME (PARticle FUel ModEl) code was used to predict the release of fission products silver, cesium, and strontium from tristructural isotropic coated fuel particles and compacts during the first irradiation experiment (AGR-1) of the Advanced Gas Reactor Fuel Development and Qualification program. The PARFUME model for the AGR-1 experiment used the fuel compact volume average temperature for each of the 620 days of irradiation to calculate the release of silver, cesium, and strontium from a representative particle for a select number of AGR-1 compacts. Post-irradiation examination measurements provided data on release of these fission products from fuel compacts andmore » fuel particles, and retention of silver in the compacts outside of the silicon carbide (SiC) layer. PARFUME-predicted fractional release of silver, cesium, and strontium was determined and compared to the PIE measurements. For silver, comparisons show a trend of over-prediction at low burnup and under-prediction at high burnup. PARFUME has limitations in the modeling of the temporal and spatial distributions of the temperature and burnup across the compacts, which affects the accuracy of its predictions. Nevertheless, the comparisons on silver release lie in the same order of magnitude. Results show an overall over-prediction of the fractional release of cesium by PARFUME. For particles with failed SiC layers, the over-prediction is by a factor of up to 3, corresponding to a potential over-estimation of the diffusivity in uranium oxycarbide (UCO) by a factor of up to 250. For intact particles, whose release is much lower, the over-prediction is by a factor of up to 100, which could be attributed to an over-estimated diffusivity in SiC by about 40% on average. The release of strontium from intact particles is also over-predicted by PARFUME, which also points towards an over-estimated diffusivity of strontium in either SiC or UCO, or possibly both. The measured strontium fractional release

  11. Comparison of silver, cesium, and strontium release predictions using PARFUME with results from the AGR-1 irradiation experiment

    NASA Astrophysics Data System (ADS)

    Collin, Blaise P.; Petti, David A.; Demkowicz, Paul A.; Maki, John T.

    2015-11-01

    The PARFUME (PARticle FUel ModEl) code was used to predict the release of fission products silver, cesium, and strontium from tristructural isotropic coated fuel particles and compacts during the first irradiation experiment (AGR-1) of the Advanced Gas Reactor Fuel Development and Qualification program. The PARFUME model for the AGR-1 experiment used the fuel compact volume average temperature for each of the 620 days of irradiation to calculate the release of silver, cesium, and strontium from a representative particle for a select number of AGR-1 compacts. Post-irradiation examination (PIE) measurements provided data on release of these fission products from fuel compacts and fuel particles, and retention of silver in the compacts outside of the silicon carbide (SiC) layer. PARFUME-predicted fractional release of silver, cesium, and strontium was determined and compared to the PIE measurements. For silver, comparisons show a trend of over-prediction at low burnup and under-prediction at high burnup. PARFUME has limitations in the modeling of the temporal and spatial distributions of the temperature and burnup across the compacts, which affects the accuracy of its predictions. Nevertheless, the comparisons on silver release lie in the same order of magnitude. Results show an overall over-prediction of the fractional release of cesium by PARFUME. For particles with failed SiC layers, the over-prediction is by a factor of up to 3, corresponding to a potential over-estimation of the diffusivity in uranium oxycarbide (UCO) by a factor of up to 250. For intact particles, whose release is much lower, the over-prediction is by a factor of up to 100, which could be attributed to an over-estimated diffusivity in SiC by about 40% on average. The release of strontium from intact particles is also over-predicted by PARFUME, which also points towards an over-estimated diffusivity of strontium in either SiC or UCO, or possibly both. The measured strontium fractional release

  12. HTR-2014 Paper Comparison of fission product release predictions using PARFUME with results from the AGR-1 irradiation experiment

    SciTech Connect

    Blaise Collin

    2001-10-01

    The PARFUME (PARticle FUel ModEl) code was used to predict fission product release from tristructural isotropic (TRISO) coated fuel particles and compacts during the first irradiation experiment (AGR-1) of the Advanced Gas Reactor Fuel Development and Qualification program. The PARFUME model for the AGR-1 experiment used the fuel compact volume average temperature for each of the 620 days of irradiation to calculate the release of fission products silver, cesium, and strontium from a representative particle for a select number of AGR-1 compacts. Post-irradiation examination (PIE) measurements provided data on release of fission products from fuel compacts and fuel particles, and retention of fission products in the compacts outside of the SiC layer. PARFUME-predicted fractional release of these fission products was determined and compared to the PIE measurements. Results show an overall over-prediction of the fractional release of cesium by PARFUME. For particles with failed silicon carbide (SiC) layers, the over-prediction is by a factor of about two, corresponding to an over-estimation of the diffusivity in uranium oxycarbide (UCO) by a factor of about 100. For intact particles, whose release is much lower, the over-prediction is by an average of about an order of magnitude, which could additionally be attributed to an over-estimated diffusivity in SiC by about 30%. The release of strontium from intact particles is also over-estimated by PARFUME, which also points towards an over-estimated diffusivity of strontium in either SiC or UCO, or possibly both. The measured strontium fractional release from intact particles varied considerably from compact to compact, making it difficult to assess the effective over-estimation of the diffusivities. Furthermore, the release of strontium from particles with failed SiC is difficult to observe experimentally due to the release from intact particles, preventing any conclusions to be made on the accuracy or validity of the

  13. Comparison and modeling of effects of normal and reduced precipitation supply in field experiment with spring barley

    NASA Astrophysics Data System (ADS)

    Pohanková, Eva; Orság, Matěj; Fischer, Milan; Hlavinka, Petr

    2015-04-01

    This paper evaluates two-year (2013 and 2014) results of field experiments with spring barley (cultivar Bojos) under reduced precipitation supply. The field experiments were carried out at the experimental station in Domanínek (Czech Republic; 49°31,470'N, 16°14,400'E, altitude 530 m a.s.l.) and conducted by Institute of Agrosystems and bioclimatology at Mendel Univerzity in Brno in cooperation with Global Change Research Centre AS CR. The field experiments consisted of small plots in two variants and three repetitions. The first variant was uncovered the second was partially covered to exclude rain through out the whole vegetation season. For the partial covering of the plot, a material which transmits solar radiation and diverts rainwater away from the percentage coverage of the plots was used. In 2013, the covered area of the experimental plot was 30%, and in 2014, it was 70%. The main aim was to determine whether there are any differences in the spring barley's development, growth and yield in the uncovered and the partially covered plots, and a comparison of the results. Firstly, differences of key parameters (seasonal dynamics of the leaf area index and above ground biomass, soil water content, yield components and yields) compared; secondly, the results of the field experiments served as input data for the crop growth model DAISY. Subsequently, the crop growth model' ability to simulate crop growth and crop development which were affected by the drought stress was explored. The results were assessed using the following statistical indexes: root mean square error (RMSE) and mean bias error (MBE). This study was funded by project "Building up a multidisciplinary scientific team focused on drought" No. CZ.1.07/2.3.00/20.0248, NAZV-JPI - project supported by Czech National Agency of Agricultural Research No. QJ1310123 "Crop modelling as a tool for increasing the production potential and food security of the Czech Republic under Climate Change" and project LD

  14. Effects of upward and downward social comparison information on the efficacy of an appearance-based sun protection intervention: a randomized, controlled experiment

    PubMed Central

    Kulik, James A.; Gerrard, Meg; Gibbons, Frederick X.

    2010-01-01

    This experiment examined the impact of adding upward and/or downward social comparison information on the efficacy of an appearance-based sun protection intervention (UV photos and photoaging information). Southern California college students (N = 126) were randomly assigned to one of four conditions: control, intervention, intervention plus upward social comparison, intervention plus downward social comparison. The results demonstrated that all those who received the basic UV photo/photoaging intervention reported greater perceived susceptibility to photoaging (d = .74), less favorable tanning cognitions (d = .44), and greater intentions to sun protect (d = 1.32) relative to controls. Of more interest, while the basic intervention increased sun protective behavior during the subsequent 5 weeks relative to controls (d = .44), the addition of downward comparison information completely negated this benefit. Upward comparison information produced sun protection levels that were only slightly (and nonsignificantly) greater than in the basic intervention condition and, as such, does not appear to be a cost-effective addition. Possible mechanisms that may have reduced the benefits of upward comparison information and contributed to the undermining effects of downward comparison information are discussed. PMID:20652391

  15. Choice of experimental venue matters in ecotoxicology studies: Comparison of a laboratory-based and an outdoor mesocosm experiment.

    PubMed

    Mikó, Zsanett; Ujszegi, János; Gál, Zoltán; Imrei, Zoltán; Hettyey, Attila

    2015-10-01

    The heavy application of pesticides and its potential effects on natural communities has attracted increasing attention to inadvertent impacts of these chemicals. Toxicologists conventionally use laboratory-based tests to assess lethal concentrations of pesticides. However, these tests often do not take into account indirect, interactive and long-term effects, and tend to ignore different rates of disintegration in the laboratory and under natural conditions. Our aim was to investigate the importance of the experimental venue for ecotoxicology tests. We reared tadpoles of the agile frog (Rana dalmatina) in the laboratory and in outdoor mesocosms and exposed them to three initial concentrations of a glyphosate-based herbicide (0, 2 and 6.5 mg a.e./L glyphosate), and to the presence or absence of caged predators (dragonfly larvae). The type of experimental venue had a large effect on the outcome: The herbicide was less lethal to tadpoles reared in outdoor mesocosms than in the laboratory. Further, while the herbicide had a negative effect on development time and on body mass in the laboratory, tadpoles exposed to the herbicide in mesocosms were larger at metamorphosis and developed faster in comparison to those reared in the absence of the herbicide. The effect of the herbicide on morphological traits of tadpoles also differed between the two venues. Finally, in the presence of the herbicide, tadpoles tended to be more active and to stay closer to the bottom of laboratory containers, while tadpole behaviour shifted in the opposite direction in outdoor mesocosms. Our results demonstrate major discrepancies between results of a classic laboratory-based ecotoxicity test and outcomes of an experiment performed in outdoor mesocosms. Consequently, the use of standard laboratory tests may have to be reconsidered and their benefits carefully weighed against the difficulties of performing experiments under more natural conditions. Tests validating experimentally estimated

  16. Comparison of benefit–risk preferences of patients and physicians regarding cyclooxygenase-2 inhibitors using discrete choice experiments

    PubMed Central

    Byun, Ji-Hye; Kwon, Sun-Hong; Lee, Ji-Eun; Cheon, Ji-Eun; Jang, Eun-Jin; Lee, Eui-Kyung

    2016-01-01

    Purpose To elucidate and compare benefit–risk preferences among Korean patients and physicians concerning cyclooxygenase-2 (Cox-2) inhibitor treatments for arthritis. Materials and methods Subjects included 100 patients with arthritis and 60 board-certified orthopedic surgeon physicians in South Korea. Through a systematic review of the literature, beneficial attributes of using Cox-2 inhibitors were defined as a decrease in the Western Ontario and McMaster Universities Arthritis Index for pain score and improvement in physical function. Likewise, risk attributes included upper gastrointestinal (GI) complications and cardiovascular (CV) adverse events. Discrete choice experiments were used to determine preferences for these four attributes among Korean patients and physicians. Relative importance and maximum acceptable risk for improving beneficial attributes were assessed by analyzing the results of the discrete choice experiment by using a conditional logit model. Results Patients ranked the relative importance of benefit–risk attributes as follows: pain reduction (35.2%); physical function improvement (30.0%); fewer CV adverse events (21.5%); fewer GI complications (13.4%). The physicians’ ranking for the same attributes was as follows: fewer CV (33.5%); pain reduction (32.4%); fewer GI complications (18.1%); physical function improvement (16.0%). Patients were more willing than physicians to accept risks when pain improved from 20% or 45% to 55% and physical function improved from 15% or 35% to 45%. Conclusion We confirmed that patients and physicians had different benefit–risk preferences regarding Cox-2 inhibitors. Patients with arthritis prioritized the benefits of Cox-2 inhibitors over the risks; moreover, in comparison with the physicians, arthritis patients were more willing to accept the trade-off between benefits and risks to achieve the best treatment level. To reduce the preference gap and achieve treatment goals, physicians must better

  17. Choice of experimental venue matters in ecotoxicology studies: Comparison of a laboratory-based and an outdoor mesocosm experiment.

    PubMed

    Mikó, Zsanett; Ujszegi, János; Gál, Zoltán; Imrei, Zoltán; Hettyey, Attila

    2015-10-01

    The heavy application of pesticides and its potential effects on natural communities has attracted increasing attention to inadvertent impacts of these chemicals. Toxicologists conventionally use laboratory-based tests to assess lethal concentrations of pesticides. However, these tests often do not take into account indirect, interactive and long-term effects, and tend to ignore different rates of disintegration in the laboratory and under natural conditions. Our aim was to investigate the importance of the experimental venue for ecotoxicology tests. We reared tadpoles of the agile frog (Rana dalmatina) in the laboratory and in outdoor mesocosms and exposed them to three initial concentrations of a glyphosate-based herbicide (0, 2 and 6.5 mg a.e./L glyphosate), and to the presence or absence of caged predators (dragonfly larvae). The type of experimental venue had a large effect on the outcome: The herbicide was less lethal to tadpoles reared in outdoor mesocosms than in the laboratory. Further, while the herbicide had a negative effect on development time and on body mass in the laboratory, tadpoles exposed to the herbicide in mesocosms were larger at metamorphosis and developed faster in comparison to those reared in the absence of the herbicide. The effect of the herbicide on morphological traits of tadpoles also differed between the two venues. Finally, in the presence of the herbicide, tadpoles tended to be more active and to stay closer to the bottom of laboratory containers, while tadpole behaviour shifted in the opposite direction in outdoor mesocosms. Our results demonstrate major discrepancies between results of a classic laboratory-based ecotoxicity test and outcomes of an experiment performed in outdoor mesocosms. Consequently, the use of standard laboratory tests may have to be reconsidered and their benefits carefully weighed against the difficulties of performing experiments under more natural conditions. Tests validating experimentally estimated

  18. Comparisons of Derived Metrics from Computed Tomography (CT) Scanned Images of Fluvial Sediment from Gravel-Bed Flume Experiments

    NASA Astrophysics Data System (ADS)

    Voepel, Hal; Ahmed, Sharif; Hodge, Rebecca; Leyland, Julian; Sear, David

    2016-04-01

    Uncertainty in bedload estimates for gravel bed rivers is largely driven by our inability to characterize arrangement, orientation and resultant forces of fluvial sediment in river beds. Water working of grains leads to structural differences between areas of the bed through particle sorting, packing, imbrication, mortaring and degree of bed armoring. In this study, non-destructive, micro-focus X-ray computed tomography (CT) imaging in 3D is used to visualize, quantify and assess the internal geometry of sections of a flume bed that have been extracted keeping their fabric intact. Flume experiments were conducted at 1:1 scaling of our prototype river. From the volume, center of mass, points of contact, and protrusion of individual grains derived from 3D scan data we estimate 3D static force properties at the grain-scale such as pivoting angles, buoyancy and gravity forces, and local grain exposure. Here metrics are derived for images from two flume experiments: one with a bed of coarse grains (>4mm) and the other where sand and clay were incorporated into the coarse flume bed. In addition to deriving force networks, comparison of metrics such as critical shear stress, pivot angles, grain distributions, principle axis orientation, and pore space over depth are made. This is the first time bed stability has been studied in 3D using CT scanned images of sediment from the bed surface to depths well into the subsurface. The derived metrics, inter-granular relationships and characterization of bed structures will lead to improved bedload estimates with reduced uncertainty, as well as improved understanding of relationships between sediment structure, grain size distribution and channel topography.

  19. Comparison of Dental Caries Experience in Children Suffering From Epilepsy with and without Administration of Long Term Liquid Oral Medication

    PubMed Central

    Bhadravathi, Manjunath Chaluvaiah; Kumar, Adarsh; Narang, Ridhi; Gupta, Ambika; Singh, Harneet

    2016-01-01

    Introduction Sucrose is added as sweetening agent in liquid oral medication (LOM) to mask the acrid taste of medicines which may be potentially cariogenic. Many children under long term LOM therapy for treatment of epilepsy may be susceptible to dental caries. Aim To assess and compare dental caries experience in children under long term liquid oral medication with those not under such medication among 2-12 years old children suffering from epilepsy. Materials and Methods A cross-sectional study was undertaken on a total of 84 children aged 2–12 years, who were suffering from epilepsy receiving liquid oral medication for more than 3 months were selected (study group) and for comparison 106 children of similar age group and disease but on other forms of medication were included as control group. Dental caries was assessed using DMFT/DMFS (Decayed, Missing, Fillled Teeth / Surfaces), dmft/dft and dmfs/dfs indices. One-way ANOVA and t-test were used with p-value fixed at 0.05. Univariate logistic regression was applied. Results Children on LOM were at increased risk of dental caries than those with other forms of medications (OR: 2.55, 95% CI (2.37-4.15) p=0.000, HS). Caries prevalence was high in the study group (76.1%) when compared to control group (55.6%). Conclusion Long term use of liquid medicines containing sucrose is a risk factor for dental caries among children with epilepsy. PMID:27504416

  20. A comparison of airborne and ground-based radar observations with rain gages during the CaPE experiment

    NASA Technical Reports Server (NTRS)

    Satake, Makoto; Short, David A.; Iguchi, Toshio

    1992-01-01

    The vicinity of KSC, where the primary ground truth site of the Tropical Rainfall Measuring Mission (TRMM) program is located, was the focal point of the Convection and Precipitation/Electrification (CaPE) experiment in Jul. and Aug. 1991. In addition to several specialized radars, local coverage was provided by the C-band (5 cm) radar at Patrick AFB. Point measurements of rain rate were provided by tipping bucket rain gage networks. Besides these ground-based activities, airborne radar measurements with X- and Ka-band nadir-looking radars on board an aircraft were also recorded. A unique combination data set of airborne radar observations with ground-based observations was obtained in the summer convective rain regime of central Florida. We present a comparison of these data intending a preliminary validation. A convective rain event was observed simultaneously by all three instrument types on the evening of 27 Jul. 1991. The high resolution aircraft radar was flown over convective cells with tops exceeding 10 km and observed reflectivities of 40 to 50 dBZ at 4 to 5 km altitude, while the low resolution surface radar observed 35 to 55 dBZ echoes and a rain gage indicated maximum surface rain rates exceeding 100 mm/hr. The height profile of reflectivity measured with the airborne radar show an attenuation of 6.5 dB/km (two way) for X-band, corresponding to a rainfall rate of 95 mm/hr.

  1. Defect printability of ArF alternative phase-shift mask: a critical comparison of simulation and experiment

    NASA Astrophysics Data System (ADS)

    Ozawa, Ken; Komizo, Tooru; Ohnuma, Hidetoshi

    2002-07-01

    An alternative phase shift mask (alt-PSM) is a promising device for extending optical lithography to finer design rules. There have been few reports, however, on the mask's ability to identify phase defects. We report here an alt-PSM of a single-trench type with undercut for ArF exposure, with programmed phase defects used to evaluate defect printability by measuring aerial images with a Zeiss MSM193 measuring system. The experimental results are simulated using the TEMPEST program. First, a critical comparison of the simulation and the experiment is conducted. The actual measured topographies of quartz defects are used in the simulation. Moreover, a general simulation study on defect printability using an alt-PSM for ArF exposure is conducted. The defect dimensions, which produce critical CD errors, are determined by simulation that takes into account the full 3-dimensional structure of phase defects as well as a simplified structure. The critical dimensions of an isolated bump defect identified by the alt-PSM of a single-trench type with undercut for ArF exposure are 300 nm in bottom dimension and 74 degrees in height (phase) for the real shape, where the depth of wet-etching is 100 nm and the CD error limit is +/- 5 percent.

  2. Biomechanical comparison of straight and helical compression plates for fixation of transverse and oblique bone fractures: Modeling and experiments.

    PubMed

    Sezek, Sinan; Aksakal, Bunyamin; Gürger, Murat; Malkoc, Melih; Say, Y

    2016-08-12

    Total deformation and stability of straight and helical compression plates were studied by means of the finite element method (FEM) and in vitro biomechanical experiments. Fixations of transverse (TF) and oblique (45°) bone (OF) fractures have been analyzed on sheep tibias by designing the straight compression (SP) and Helical Compression Plate (HP) models. The effects of axial compression, bending and torsion loads on both plating systems were analyzed in terms of total displacements. Numerical models and experimental models suggested that under compression loadings, bone fracture gap closures for both fracture types were found to be in the favor of helical plate designs. The helical plate (HP) fixations provided maximum torsional resistance compared to the (SP) fixations. The fracture gap closure and stability of helical plate fixation for transverse fractures was determined to be higher than that found for the oblique fractures. The comparison of average compression stress, bending and torsion moments showed that the FEM and experimental results are in good agreement and such designs are likely to have a positive impact in future bone fracture fixation designs.

  3. A comparison of airborne and ground-based radar observations with rain gages during the CaPE experiment

    NASA Technical Reports Server (NTRS)

    Satake, Makoto; Short, David A.; Iguchi, Toshio

    1992-01-01

    The vicinity of KSC, where the primary ground truth site of the Tropical Rainfall Measuring Mission (TRMM) program is located, was the focal point of the Convection and Precipitation/Electrification (CaPE) experiment in July and Aug. 1991. In addition to several specialized radars, local coverage was provided by the C-band (5 cm) radar at Patrick AFB. Point measurements of rain rate were provided by tipping bucket rain gage networks. Besides these ground-based activities, airborne radar measurements with X- and Ka-band nadir-looking radars on board an aircraft were also recorded. A unique combination data set of airborne radar observations with ground-based observations was obtained in the summer convective rain regime of central Florida. We present a comparison of these data intending a preliminary validation. A convective rain event was observed simultaneously by all three instrument types on the evening of 27 July 1991. The high resolution aircraft radar was flown over convective cells with tops exceeding 10 km and observed reflectivities of 40 to 50 dBZ at 4 to 5 km altitude, while the low resolution surface radar observed 35 to 55 dBZ echoes and a rain gage indicated maximum surface rain rates exceeding 100 mm/hr. The height profile of reflectivity measured with the airborne radar show an attenuation of 6.5 dB/km (two way) for X-band, corresponding to a rainfall rate of 95 mm/hr.

  4. Biomechanical comparison of straight and helical compression plates for fixation of transverse and oblique bone fractures: Modeling and experiments.

    PubMed

    Sezek, Sinan; Aksakal, Bunyamin; Gürger, Murat; Malkoc, Melih; Say, Y

    2016-08-12

    Total deformation and stability of straight and helical compression plates were studied by means of the finite element method (FEM) and in vitro biomechanical experiments. Fixations of transverse (TF) and oblique (45°) bone (OF) fractures have been analyzed on sheep tibias by designing the straight compression (SP) and Helical Compression Plate (HP) models. The effects of axial compression, bending and torsion loads on both plating systems were analyzed in terms of total displacements. Numerical models and experimental models suggested that under compression loadings, bone fracture gap closures for both fracture types were found to be in the favor of helical plate designs. The helical plate (HP) fixations provided maximum torsional resistance compared to the (SP) fixations. The fracture gap closure and stability of helical plate fixation for transverse fractures was determined to be higher than that found for the oblique fractures. The comparison of average compression stress, bending and torsion moments showed that the FEM and experimental results are in good agreement and such designs are likely to have a positive impact in future bone fracture fixation designs. PMID:27567775

  5. Abinitio calculations of the spectral shapes of CO2 isolated lines including non-Voigt effects and comparisons with experiments

    NASA Astrophysics Data System (ADS)

    Hartmann, J.-M.; Tran, H.; Ngo, N. H.; Landsheere, X.; Chelin, P.; Lu, Y.; Liu, A.-W.; Hu, S.-M.; Gianfrani, L.; Casa, G.; Castrillo, A.; Lepère, M.; Delière, Q.; Dhyne, M.; Fissiaux, L.

    2013-01-01

    We present a fully ab initio model and calculations of the spectral shapes of absorption lines in a pure molecular gas under conditions where the influences of collisions and of the Doppler effect are significant. Predictions of the time dependence of dipole autocorrelation functions (DACFs) are made for pure CO2 at room temperature using requantized classical molecular dynamics simulations. These are carried, free of any adjusted parameter, on the basis of an accurate anisotropic intermolecular potential. The Fourier-Laplace transforms of these DACFs then yield calculated spectra which are analyzed, as some measured ones, through fits using Voigt line profiles. Comparisons between theory and various experiments not only show that the main line-shape parameters (Lorentz pressure-broadening coefficients) are accurately predicted, but that subtle observed non-Voigt features are also quantitatively reproduced by the model. These successes open renewed perspectives for the understanding of the mechanisms involved (translational-velocity and rotational-state changes and their dependences on the molecular speed) and the quantification of their respective contributions. The proposed model should also be of great help for the test of widely used empirical line-shape models and, if needed, the construction of more physically based ones.

  6. Comparison of Hydraulic Methods and Tracer Experiments as Applied to the Development of Conceptual Models for Discrete Fracture Networks

    NASA Astrophysics Data System (ADS)

    Novakowski, K. S.

    2015-12-01

    The development of conceptual models for solute migration in discrete fracture networks has typically been based on a combination of core logs, borehole geophysics, and some form of single-well hydraulic test using discrete zones. More rarely, interwell hydraulic tests and interwell tracer experiments are utilised to directly explore potential transport pathways. The latter methods are less widely employed simply due to potentially significant increases in the cost and effort in site characterization. To date however there is a paucity of literature comparing the efficacy of the standard procedure with what should be more definitive identification of transport pathways using interwell methods. In the present study, a detailed comparison is conducted by developing conceptual models from three separate data sets, the first based on core logs, geology and single-well hydraulic tests, the second based on a large suite of pulse interference tests, and the third based on a series of radially-divergent and injection-withdrawal tracer experiments. The study was conducted in an array of five HQ-sized wells, 28-32 m in depth and arranged in a five star pattern, 10 m on a side. The wells penetrate the contact between a Cambrian-aged limestone, and underlying Precambrian gneiss. The core was logged for potentially open fractures using a ranking system, and 87 contiguous hydraulic tests were conducted using a 0.85-m packer spacing. A total of 57 pulse interference tests were conducted using two wells as injection points, and 11 tracer experiments were conducted using either sample collection or in-situ detection via a submersible fluorometer. The results showed very distinct conceptual models depending on the data set, with the model based on the single-well testing significantly over-predicting the number and connection of solute transport pathways. The results of the pulse interference tests also over predict the transport pathways, but to a lesser degree. Quantification of

  7. NSF Research Experience for Undergraduates: 3-D Characterization and Comparison of Vegetation Structure in a Tropical Premontane Wet Forest

    NASA Astrophysics Data System (ADS)

    Washington-Allen, R. A.; Davis, K.; Falkowski, T.; Tarbox, B.; Delgado, A.; March, R.; Moore, G. W.; Tjoelker, M.; Gonzalez, E.; Houser, C.

    2011-12-01

    This National Science Foundation (NSF) Research Experience for Undergraduates (REU) site hosted by Texas A&M University to allow selected undergraduate students to conduct original research on various aspects of the ecohydrology of understudied tropical pre-montane forest at the Texas A&M Soltis Center for Research and Education in Central Costa Rica. This particular study was conducted by 3 students under the guidance of 5 mentors who assisted in experimental design, equipment use, maintenance, and training, plant species identification and other logistical requirements. The goal of this study was to determine the change in 3-D structure of tropical premontane wet forest under 3 different land uses: a carbon tree farm, secondary logged forest, and primary unlogged forest. Traditional forest mensuration techniques including glass prisms (stand basal area), laser clinometers (height), vertical and horizontal PAR, spherical densiometers, and hemispherical photography (GAP fraction and LAI) and, root cores, and diameter-at-breast height (DBH) tapes were acquired in one 30-m diameter plot per land and use compared to similar metrics collected by a terrestrial scanning laser (TSL) and ground penetrating radar (GPR) at 400 MHz and 1.5 GHz across 3 land uses along an elevation gradient from ~380-masl to 525-masl. Besides discovery, another goal of this study was to see if the TSL and GPR can help meet the Tier 2 and 3 monitoring and verification goals of the United Nations Collaborative Programme on Reducing Emissions from Deforestation and Forest Degradation in Developing Countries for estimating above- and below-ground biomass using remote sensing. This is of particular importance because the GPR may be able to capture below-ground biomass in a more efficient manner than traditional coring and the TSL and GPR can capture data on highly sloped terrain where both airborne and satellite RADAR and LIDAR are limited. The 50, 000 pts/sec 532 nm TSL collected 3 to 5 scans per

  8. Kinetics of hybridization on surface oligonucleotide microchips: theory, experiment, and comparison with hybridization on gel-based microchips.

    PubMed

    Sorokin, N V; Chechetkin, V R; Pan'kov, S V; Somova, O G; Livshits, M A; Donnikov, M Y; Turygin, A Y; Barsky, V E; Zasedatelev, A S

    2006-08-01

    The optimal design of oligonucleotide microchips and efficient discrimination between perfect and mismatch duplexes strongly depend on the external transport of target DNA to the cells with immobilized probes as well as on respective association and dissociation rates at the duplex formation. In this paper we present the relevant theory for hybridization of DNA fragments with oligonucleotide probes immobilized in the cells on flat substrate. With minor modifications, our theory also is applicable to reaction-diffusion hybridization kinetics for the probes immobilized on the surface of microbeads immersed in hybridization solution. The main theoretical predictions are verified with control experiments. Besides that, we compared the characteristics of the surface and gel-based oligonucleotide microchips. The comparison was performed for the chips printed with the same pin robot, for the signals measured with the same devices and processed by the same technique, and for the same hybridization conditions. The sets of probe oligonucleotides and the concentrations of probes in respective solutions used for immobilization on each platform were identical as well. We found that, despite the slower hybridization kinetics, the fluorescence signals and mutation discrimination efficiency appeared to be higher for the gel-based microchips with respect to their surface counterparts even for the relatively short hybridization time about 0.5-1 hour. Both the divergence between signals for perfects and the difference in mutation discrimination efficiency for the counterpart platforms rapidly grow with incubation time. In particular, for hybridization during 3 h the signals for gel-based microchips surpassed their surface counterparts in 5-20 times, while the ratios of signals for perfect-mismatch pairs for gel microchips exceeded the corresponding ratios for surface microchips in 2-4 times. These effects may be attributed to the better immobilization efficiency and to the higher

  9. Dynamics of the D+ + H2 and H+ + D2 reactions: a detailed comparison between theory and experiment.

    PubMed

    Jambrina, P G; Alvariño, J M; Gerlich, D; Hankel, M; Herrero, V J; Sáez-Rábanos, V; Aoiz, F J

    2012-03-14

    An extensive set of experimental measurements on the dynamics of the H(+) + D(2) and D(+) + H(2) ion-molecule reactions is compared with the results of quantum mechanical (QM), quasiclassical trajectory (QCT), and statistical quasiclassical trajectory (SQCT) calculations. The dynamical observables considered include specific rate coefficients as a function of the translational energy, E(T), thermal rate coefficients in the 100-500 K temperature range. In addition, kinetic energy spectra (KES) of the D(+) ions reactively scattered in H(+) + D(2) collisions are also presented for translational energies between 0.4 eV and 2.0 eV. For the two reactions, the best global agreement between experiment and theory over the whole energy range corresponds to the QCT calculations using a gaussian binning (GB) procedure, which gives more weight to trajectories whose product vibrational action is closer to the actual integer QM values. The QM calculations also perform well, although somewhat worse over the more limited range of translational energies where they are available (E(T) < 0.6 eV and E(T) < 0.2 eV for the H(+) + D(2) and D(+) + H(2) reactions, respectively). The worst agreement is obtained with the SQCT method, which is only adequate for low translational energies. The comparison between theory and experiment also suggests that the most reliable rate coefficient measurements are those obtained with the merged beams technique. It is worth noting that none of the theoretical approaches can account satisfactorily for the experimental specific rate coefficients of H(+) + D(2) for E(T)≤ 0.2 eV although there is a considerable scatter in the existing measurements. On the whole, the best agreement with the experimental laboratory KES is obtained with the simulations carried out using the state resolved differential cross sections (DCSs) calculated with the QCT-GB method, which seems to account for most of the observed features. In contrast, the simulations with the SQCT data

  10. Monitoring transport conditions of key comparison travelling standards using a data logger. Experiences from key comparison CCAUV.U-K3.1

    NASA Astrophysics Data System (ADS)

    Haller, Julian; Koch, Christian

    2015-12-01

    In the framework of the international key comparison CCAUV.U-K3.1, a data logger was used to monitor temperature, pressure, humidity, and acceleration during transportation of an artefact travelling between participating laboratories. From the recorded data, environmental conditions of different kinds of transportation have been investigated and corresponding recommendations for the safe and proper transfer of artefacts between laboratories could be deduced. Transportation by courier services bears the risk of strong mechanical shocks and exposure to comparably high or low temperatures due to inappropriate handling or storage and is thus only suitable for insensitive or well-packed artefacts. Quite low temperatures (T  ≈  5 °C) have been observed in the cargo area during flights, so that hand-carrying of an artefact with transportation in the passenger cabin during flights is recommended, particularly for temperature-sensitive artefacts. Significant decreases of the pressure (p  ≈  750 mbar) have been recorded both for transportation in the passenger cabin and in the cargo area. Air-tight packing is thus recommended for pressure-sensitive devices. In general, the suitability of a data logger to provide evidence of the transport conditions during a key comparison has been demonstrated and the use of such a device is recommended for all key comparisons. The data logger has also been successfully employed to validate the protection properties of the passively insulating packaging of the artefact against pressure and temperature changes.

  11. Bromine Explosions In Smog Chamber Experiments: A comparison of Cavity-Enhanced (CE) and White-cell DOAS

    NASA Astrophysics Data System (ADS)

    Buxmann, J.; Hoch, D. J.; Sihler, H.; Pöhler, D.; Platt, U.; Bleicher, S.; Balzer, N.; Zetzsch, C.

    2011-12-01

    Reactive halogen species (RHS), such as Cl, Br or BrO, can significantly influence chemical processes in the troposphere, including the destruction of ozone, change in the chemical balance of hydrogen radicals (OH, HO2), increased deposition of toxic compounds (like mercury) with potential consequences for the global climate. Previous studies have shown that salt lakes can be significant sources for gaseous RHS. Environmental conditions such as salt composition, relative humidity (RH), pH, and temperature (T) can strongly influence reactive bromine levels, but are difficult to quantify in the field. Therefore, we conducted laboratory experiments by exposing NaCl salt containing 0.33% (by weight) NaBr to simulated sunlight in a Teflon smog-chamber under various conditions of RH and ozone concentrations. BrO levels were observed by a Differential-Optical-Absorption-Spectrometer (DOAS) in combination with a multi-reflection cell (White-cell). The concentrations of OH- and Cl- radicals were quantified by the radical clock method. We present the first direct observation of BrO from the "Bromine Explosion" (auto catalytic release of reactive bromine from salt surfaces - key to ozone destruction) in the laboratory above a simulated salt pan. The maximum BrO mixing ratio of 6419±71 ppt at 60% RH was observed to be one order of magnitude higher than at 37% RH and 2% RH. The release of RHS from the salt pan is possibly controlled by the thickness of the quasi liquid layer, covering the reactive surface of the halide crystals, as the layer thickness strongly depends on RH. Furthermore, a new cavity enhanced DOAS (CE-DOAS) instrument was designed and successfully used in chamber experiments. For the first time, such an instrument uses a spectral interval in the UV - wavelength range (325-365 nm) to identify BrO. We show a comparison of the CE-DOAS and White-cell DOAS instrument in a series of experiments, where e.g. a peak BrO mixing ratio up to 380 ppt within the first

  12. Meaning-Making in Memories: A Comparison of Memories of Death-Related and Low Point Life Experiences

    ERIC Educational Resources Information Center

    Mackay, Michael M.; Bluck, Susan

    2010-01-01

    Because of their extensive experience with death and dying, hospice volunteers may be more successful at engaging in meaning-making regarding their death-related experiences than their low point life experiences (e.g., job loss). Consequently, their memories of death-related experiences will manifest more meaning-making strategies (e.g.,…

  13. Ψ and Υ Production in p-p Collisions at E = 5, 14 TeV; and Comparison with Experiment at E = 7 TeV

    NASA Astrophysics Data System (ADS)

    Kisslinger, Leonard S.; Das, Debasish

    2016-10-01

    This brief report is an extension of our recent studies of Ψ and Υ production cross sections in proton-proton collisions with E =√ {s}=13 TeV to E = 5 and E =14 TeV, using the mixed heavy quark hybrid theory in which the Ψ(2 S) and Υ(3 S) are 50 % hybrid states. Also, comparison with recent experiments at E = 7 TeV are used to test the mixed heavy hybrid theory.

  14. Comparison of cloud residual and background aerosol particle composition during the hill cap cloud experiment HCCT 2010 in Central Germany

    NASA Astrophysics Data System (ADS)

    Roth, A.; Mertes, S.; van Pinxteren, D.; Klimach, T.; Herrmann, H.; Schneider, J.; Borrmann, S.

    2013-12-01

    Physical and chemical characterization of cloud residual and background aerosol particles as well as aerosol-cloud interactions were investigated during the Hill Cap Cloud Thuringia (HCCT) experiment in September and October 2010 on the mountain site Schmücke (938m a.s.l.) in Germany. Background aerosol particles were sampled by an interstitial inlet whereas cloud droplets from orographic clouds were collected by a counter flow virtual impactor (CVI). Chemical composition analysis and sizing of the particles was done by single particle mass spectrometry using the bipolar Aircraft-based Laser Ablation Aerosol Mass Spectrometer (ALABAMA, particle diameter range 150 nm - 900 nm; Brands et al., 2011) and by two Aerodyne Aerosol Mass Spectrometers (C-ToF, HR-ToF). Supplementary, the particle size distribution was measured with an optical particle counter (OPC, size range 0.25 μm - 32 μm). During the field campaign about 21000 positive and negative single particle mass spectra could be obtained from cloud residual particles and about 239000 from background aerosol particles. The data were clustered by means of the fuzzy c-means algorithm. The resulting clusters consisting of mass spectra with similar fragmentation patterns were, dependent on presence and combination of peaks, assigned to certain particle types. For both sampled particle types a large portion is internally mixed with nitrate and/or sulfate. This might be an explanation, why a comparison of the composition shows a higher fraction of soot particles and amine-containing particles among cloud residuals. Furthermore cloud residuals show a decreased fraction of particles being internally mixed only with nitrate (10%) compared to background aerosol particles (19%) of the same air masses, whereas the fraction of particles containing both nitrate and sulfate increases from 39% to 63% indicating cloud processing by uptake and oxidation of SO2 (Harris et al, 2013). Brands, M., Kamphus, M., Böttger, T., Schneider

  15. A Comparison of Inventoried and Measured U.S. Urban/Industrial Hg Emission Factors during the NOMADSS Experiment

    NASA Astrophysics Data System (ADS)

    Ambrose, J. L., II; Gratz, L.; Jaffe, D. A.; Apel, E. C.; Campos, T. L.; Flocke, F. M.; Guenther, A. B.; Hornbrook, R. S.; Karl, T.; Kaser, L.; Knapp, D. J.; Weinheimer, A. J.; Cantrell, C. A.; Mauldin, L.; Yuan, B.

    2014-12-01

    We performed an airborne survey of some large anthropogenic mercury (Hg) emission sources in the Southeast U.S. during the 2013 Nitrogen, Oxidants, Mercury and Aerosol Distribution, Sources, and Sinks (NOMADSS) experiment. The observations included speciated atmospheric Hg, and tracers of urban/industrial emissions and associated photochemistry (e.g., carbon monoxide, CO; carbon dioxide, CO2; sulfur dioxide, SO2; nitrogen oxides (NOx); volatile organic compounds, VOCs; ozone, O3; hydroxyl radical, HO·; sulfuric acid, H2SO4) and were made from the National Science Foundation's/National Center for Atmospheric Research's C-130 research aircraft. Mercury was measured using the University of Washington's Detector for Oxidized Hg Species. We derived Hg emission factors (EF) for several U.S. urban areas and large industrial point sources, including coal-fired power plants (CFPPs) in Louisiana, Pennsylvania, Texas, and West Virginia. We compared our measured Hg EFs with inventory-based values from two separate Hg emission inventories provided by the U.S. Environmental Protection Agency - the National Emissions Inventory (NEI) and the Toxics Release Inventory (TRI). We also performed an inter-comparison of the inventory-based Hg EFs. For the CFPPs sampled, we find that actual Hg emissions differed from inventoried values by more than a factor of two in some cases. Measured Hg EFs were weakly correlated with values reported in the NEI: m = 0.71; r2 = 0.47 (p = 0.06; n = 8), whereas EFs derived from the TRI were not meaningfully predictive of the measured values: m = -3.3; r2 = 0.61 (p < 0.05; n = 8). Median absolute differences between measured and inventory-based EFs were ≥50%, relative to the inventory values. The median absolute average difference between the Hg EFs reported in the two inventories was approximately 40%. Our results place quantitative constraints on uncertainties associated with the inventoried Hg emissions. Additionally, our results suggest that the

  16. Super-thermal particles in hot plasmas—Kinetic models, numerical solution strategies, and comparison to tokamak experiments

    NASA Astrophysics Data System (ADS)

    Lauber, Philipp

    2013-12-01

    The excitation of collective instabilities by super-thermal particles in hot plasmas and the related transport processes attract increasing interest due to their fundamental challenges for theoretical models and their practical importance for burning fusion plasmas. In fact, the physics of a self-heated thermonuclear plasma due to fusion-born 3.5 MeV α-particles is one of the most important outstanding fundamental research topics on the way to a fusion power plant with magnetic confinement. Within the last 10 years significant advances on both the theoretical and the experimental sides have been made leading to a more detailed and quantitative understanding of fast-particle-driven instabilities. On the theoretical side, the crucial step was to move from fluid models for the plasma background with a hybrid kinetic expression for the energetic particles to a fully kinetic model for all the plasma species, i.e. background ions, background electrons, and fast ions. This improvement allows one to describe consistently the resonant interaction between global plasma waves such as shear Alfvén and Alfvén-acoustic waves, and the particles via Landau damping, i.e. the dynamics parallel to the magnetic background field. Also, mode conversion mechanisms require the inclusion of background ion scales in a kinetic, non-perturbative way. This accurate treatment of the plasma background leads not only to changes in the linear mode properties such as frequency, growth/damping rate, and mode structure but also influences the non-linear dynamics. Due to major advances, innovations and installation of diagnostics in present day experiments, this comparison can be carried out in a more detailed and comprehensive way than a few years ago. For example, the measurement of damping rates via active external antennas, the imaging of 2D mode structures via electron-cyclotron-emission spectroscopy, and the direct detection of escaping fast ions allow to diagnose various kinetic features of

  17. A Post-Flight Comparison Between GPS Signal Generator and On-Orbit Testing Results from the STS-101 and STS-106 SOAR Shuttle Flight Experiment

    NASA Technical Reports Server (NTRS)

    Simpson, James; Gomez, Susan; Bauer, Frank H. (Technical Monitor)

    2001-01-01

    The use of a GPS Signal Generator (GPSSG) prior to launch for verification of a GPS subsystem and GN&C system on a spacecraft is becoming a very common practice. The level of confidence in the verification created by running a receiver with a GPSSG can greatly impact both schedule and cost of spacecraft development. This paper addresses the comparison of the Space Shuttle STS-101 and STS-106 Space Integrated GPS/INS (SIGI) Orbital Attitude Readiness (SOAR) flight experiments on-orbit performance with the performance from the same receiver on a Global Simulation Systems (GSS) GPSSG. The SOAR flight experiment was designed to demonstrate on-orbit performance of the International Space Station Force-19 GPS receiver. This paper discusses the process involved in getting the post-flight Best Estimate of Trajectory and Best Estimate of Attitude into the GPSSG such that the Force-19 receiver will experience the same trajectory and environmental conditions as observed during the SOAR flight experiment. Results of the comparison conclude with recommendations of how better to construct and interpret results from receiver tests using a GSS GPSSG.

  18. COMPARISON OF EXPERIMENTS TO CFD MODELS FOR MIXING USING DUAL OPPOSING JETS IN TANKS WITH AND WITHOUT INTERNAL OBSTRUCTIONS

    SciTech Connect

    Leishear, R.; Poirier, M.; Lee, S.; Fowley, M.

    2012-06-26

    This paper documents testing methods, statistical data analysis, and a comparison of experimental results to CFD models for blending of fluids, which were blended using a single pump designed with dual opposing nozzles in an eight foot diameter tank. Overall, this research presents new findings in the field of mixing research. Specifically, blending processes were clearly shown to have random, chaotic effects, where possible causal factors such as turbulence, pump fluctuations, and eddies required future evaluation. CFD models were shown to provide reasonable estimates for the average blending times, but large variations -- or scatter -- occurred for blending times during similar tests. Using this experimental blending time data, the chaotic nature of blending was demonstrated and the variability of blending times with respect to average blending times were shown to increase with system complexity. Prior to this research, the variation in blending times caused discrepancies between CFD models and experiments. This research addressed this discrepancy, and determined statistical correction factors that can be applied to CFD models, and thereby quantified techniques to permit the application of CFD models to complex systems, such as blending. These blending time correction factors for CFD models are comparable to safety factors used in structural design, and compensate variability that cannot be theoretically calculated. To determine these correction factors, research was performed to investigate blending, using a pump with dual opposing jets which re-circulate fluids in the tank to promote blending when fluids are added to the tank. In all, eighty-five tests were performed both in a tank without internal obstructions and a tank with vertical obstructions similar to a tube bank in a heat exchanger. These obstructions provided scale models of vertical cooling coils below the liquid surface for a full scale, liquid radioactive waste storage tank. Also, different jet

  19. The American Indian Family in Los Angeles: A Comparison of Premigration Experience, Postmigration Residence and Employment Mobility, and Coping Strategies.

    ERIC Educational Resources Information Center

    Weibel, Joan

    Urban adaptation patterns of male and female American Indians were investigated via comparison of premigration statistics (48 Navajo and 40 Oklahoma families) with postmigration statistics on a sample of 23 Navajo and 21 Oklahoma families now living in Los Angeles. The premigration variables were residence patterns; population density;…

  20. Birch's Law for high-pressure metals and ionic solids: Sound velocity data comparison between shock wave experiments and recent diamond anvil cell experiments

    NASA Astrophysics Data System (ADS)

    Boness, David; Ware, Lucas

    2015-06-01

    Sound velocity-density systematics has long been a fruitful way to take shock wave measurements on elements, alloys, oxides, rocks, and other materials, and allow reasonable extrapolation to densities found deep in the Earth. Recent detection of super-Earths has expanded interest in terrestrial planetary interiors to an even greater range of materials and pressures. Recent published DAC experimental measurements of sound velocities in iron and iron alloys, relevant to planetary cores, are inconsistent with each other with regard to the validity of Birch's Law, a linear relation between sound velocity and density. We examine the range of validity of Birch's Law for several shocked metallic elements, including iron, and shocked ionic solids and make comparisons to the recent DAC data.

  1. Do prevailing societal models influence reports of near-death experiences?: a comparison of accounts reported before and after 1975.

    PubMed

    Athappilly, Geena K; Greyson, Bruce; Stevenson, Ian

    2006-03-01

    Transcendental near-death experiences show some cross-cultural variation that suggests they may be influenced by societal beliefs. The prevailing Western model of near-death experiences was defined by Moody's description of the phenomenon in 1975. To explore the influence of this cultural model, we compared near-death experience accounts collected before and after 1975. We compared the frequency of 15 phenomenological features Moody defined as characteristic of near-death experiences in 24 accounts collected before 1975 and in 24 more recent accounts matched on relevant demographic and situational variables. Near-death experience accounts collected after 1975 differed from those collected earlier only in increased frequency of tunnel phenomena, which other research has suggested may not be integral to the experience, and not in any of the remaining 14 features defined by Moody as characteristic of near-death experiences. These data challenge the hypothesis that near-death experience accounts are substantially influenced by prevailing cultural models.

  2. Comparison of CFD simulations to non-rotating MEXICO blades experiment in the LTT wind tunnel of TUDelft

    NASA Astrophysics Data System (ADS)

    Zhang, Ye; van Zuijlen, Alexander; van Bussel, Gerard

    2014-06-01

    In this paper, three dimensional flow over non-rotating MEXICO blades is simulated by CFD methods. The numerical results are compared with the latest MEXICO wind turbine blades measurements obtained in the low speed low turbulence (LTT) wind tunnel of Delft University of Technology. This study aims to validate CFD codes by using these experimental data measured in well controlled conditions. In order to avoid use of wind tunnel corrections, both the blades and the wind tunnel test section are modelled in the simulations. The ability of Menter's k - ω shear stress transport (SST) turbulence model is investigated at both attached flow and massively separated flow cases. Steady state Reynolds averaged Navier Stokes (RANS) equations are solved in these computations. The pressure distribution at three measured sections are compared under the conditions of different inflow velocities and a range of angles of attack. The comparison shows that at attached flow condition, good agreement can be obtained for all three airfoil sections. Even with massively separated flow, still fairly good pressure distribution comparison can be found for the DU and NACA airfoil sections, although the RISØ section shows poor comparison. At the near stall case, considerable deviations exists on the forward half part of the upper surface for all three sections.

  3. Cross-national comparison of prenatal methamphetamine exposure on infant and early child physical growth: a natural experiment.

    PubMed

    Abar, Beau; LaGasse, Linda L; Wouldes, Trecia; Derauf, Chris; Newman, Elana; Shah, Rizwan; Smith, Lynne M; Arria, Amelia M; Huestis, Marilyn A; DellaGrotta, Sheri; Dansereau, Lynne M; Wilcox, Tara; Neal, Charles R; Lester, Barry M

    2014-10-01

    The current study seeks to compare the effects of prenatal methamphetamine exposure (PME) on infant and child physical growth between the USA and New Zealand (NZ). This cross-national comparison provides a unique opportunity to examine the potential impact of services provided to drug using mothers on child health. The longitudinal Infant Development, Environment and Lifestyle study of PME from birth to 36 months was conducted in the USA and NZ. The US cohort included 204 children with PME and 212 non-PME matched comparisons (NPME); the NZ cohort included 108 children with PME and 115 NPME matched comparisons. Latent growth curve models were used to examine effects of PME, country of origin, and the country × PME interaction on growth in length/height and weight. In regard to length/height, PME and country of origin were associated with initial length and growth over time. There was also a significant interaction effect, such that children with PME in the USA were shorter at birth than children with PME in NZ after controlling for other prenatal exposures, infant set, socioeconomic status, and maternal height. In regard to weight, there was only an effect of country of origin. Effects of PME on infant and child growth were shown to differ across countries, with exposed children in NZ faring better than exposed children in the USA. Implications for prevention programs and public policy are discussed.

  4. Impact of dynamic specimen shape evolution on the atom probe tomography results of doped epitaxial oxide multilayers: Comparison of experiment and simulation

    SciTech Connect

    Madaan, Nitesh; Nandasiri, Manjula; Devaraj, Arun; Bao, Jie; Xu, Zhijie; Thevuthasan, Suntharampillai

    2015-08-31

    The experimental atom probe tomography (APT) results from two different specimen orientations (top-down and sideways) of a high oxygen ion conducting Samaria-doped-ceria/Scandia-stabilized-zirconia multilayer thin film solid oxide fuel cell electrolyte was compared with level-set method based field evaporation simulations for the same specimen orientations. This experiment-simulation comparison explains the dynamic specimen shape evolution and ion trajectory aberrations that can induce density artifacts in final reconstruction, leading to inaccurate estimation of interfacial intermixing. This study highlights the importance of comparing experimental results with field evaporation simulations when using APT to study oxide heterostructure interfaces.

  5. Complex partial epileptic-like experiences in university students and practitioners of Dharmakaya in Thailand: comparison with Canadian university students.

    PubMed

    Murphy, T; Persinger, M A

    2001-08-01

    We tested the hypothesis that individuals who frequently practice meditation within another culture whose assumptions explicitly endorse this practice should exhibit more frequent and varied experience associated with complex partial epilepsy (without the seizures) as inferred by the Personal Philosophy Inventory and Roberts' Questionnaire for the Epileptic Spectrum Disorder. 80 practitioners of Dharma Meditation and 24 university students in Thailand were compared with 76 students from first-year courses in psychology in a Canadian university. Although there were large significant differences for some items and clusters of items expected as a result of cultural differences, there were no statistically significant differences between the two populations for the proportions of complex partial epileptic-like experiences or their frequency of occurrence. There were no strong or consistent correlations between the history of meditation within the sample who practiced Dharma meditation and these experiences. These results suggest complex partial epileptic-like experiences may be a normal feature of the human species.

  6. Dissipation of chlorothalonil, chlorpyrifos, and profenofos in a Malaysian agricultural soil: a comparison between the field experiment and simulation by the PERSIST model.

    PubMed

    Ismail, B S; Ngan, C K

    2005-01-01

    A comparison of dissipation of chlorothalonil, chlorpyrifos, and profenofos in a Malaysian agricultural soil between the field experiment and simulation by the PERSIST model was studied. A plot of sweet pea (Pisum sativum) from a farm in the Cameron Highlands was selected for the field experiment. The plot was treated with chlorothalonil, chlorpyrifos, and profenofos. Core soil collection was conducted according to the sampling schedule. Residues of the three pesticides were analyzed in the laboratory. Simulations of the three pesticides' persistency were also conducted using a computer-run software PERSIST. Generally, predicted data obtained using PERSIST were found to be high for the three pesticides except for one field measurement of chlorpyrifos. The predicted data for profenofos, which is the most mobile of the three pesticides tested, was not well matched with the observed data compared to chlorothalonil and chlorpyrifos. PMID:15825685

  7. Assessment of Habitat Suitability Is Affected by Plant-Soil Feedback: Comparison of Field and Garden Experiment

    PubMed Central

    Hemrová, Lucie; Knappová, Jana; Münzbergová, Zuzana

    2016-01-01

    Background Field translocation experiments (i.e., the introduction of seeds or seedlings of different species into different localities) are commonly used to study habitat associations of species, as well as factors limiting species distributions and local abundances. Species planted or sown in sites where they naturally occur are expected to perform better or equally well compared to sites at which they do not occur or are rare. This, however, contrasts with the predictions of the Janzen-Connell hypothesis and commonly reported intraspecific negative plant-soil feedback. The few previous studies indicating poorer performance of plants at sites where they naturally occur did not explore the mechanisms behind this pattern. Aims and Methods In this study, we used field translocation experiments established using both seeds and seedlings to study the determinants of local abundance of four dominant species in grasslands. To explore the possible effects of intraspecific negative plant-soil feedback on our results, we tested the effect of local species abundance on the performance of the plants in the field experiment. In addition, we set up a garden experiment to explore the intensity of intraspecific as well as interspecific feedback between the dominants used in the experiment. Key Results In some cases, the distribution and local abundances of the species were partly driven by habitat conditions at the sites, and species performed better at their own sites. However, the prevailing pattern was that the local dominants performed worse at sites where they naturally occur than at any other sites. Moreover, the success of plants in the field experiment was lower in the case of higher intraspecific abundance prior to experimental setup. In the garden feedback experiment, two of the species performed significantly worse in soils conditioned by their species than in soils conditioned by the other species. In addition, the performance of the plants was significantly

  8. Initial results from a mesoscale atmospheric simulation system and comparisons with the AVE-SESAME I data set. [Atmospheric Variability Experiment-Severe Environmental Storms And Mesoscale Experiment

    NASA Technical Reports Server (NTRS)

    Kaplan, M. L.; Zack, J. W.; Wong, V. C.; Tuccillo, J. J.

    1982-01-01

    The development of a comprehensive mesoscale atmospheric simulation system (MASS) is described in detail. The modeling system is designed for both research and real-time forecast applications. The 14-level numerical model, which has a 48 km grid mesh, can be run over most of North America and the adjacent oceanic regions. The model employs sixth-order accurate numerics, generalized similarity theory boundary-layer physics, a sophisticated cumulus parameterization scheme, and state of the art analysis and initialization techniques. Examples of model output on the synoptic and subsynoptic scales are presented for the AVE-SESAME I field experiment on 10-11 April 1979. The model output is subjectively compared to the observational analysis and the LFM II output on the synoptic scale. Subsynoptic model output is compared to analyses generated from the AVE-SESAME I data set.

  9. Comparison of three labeled silica nanoparticles used as tracers in transport experiments in porous media. Part II: transport experiments and modeling.

    PubMed

    Vitorge, Elsa; Szenknect, Stéphanie; Martins, Jean M-F; Barthès, Véronique; Gaudet, Jean-Paul

    2014-01-01

    Three types of labeled silica nanoparticles were used in transport experiments in saturated sand. The goal of this study was to evaluate both the efficiency of labeling techniques (fluorescence (FITC), metal (Ag(0) core) and radioactivity ((110m)Ag(0) core)) in realistic transport conditions and the reactive transport of silica nanocolloids of variable size and concentration in porous media. Experimental results obtained under contrasted experimental conditions revealed that deposition in sand is controlled by nanoparticles size and ionic strength of the solution. A mathematical model is proposed to quantitatively describe colloid transport. Fluorescent labeling is widely used to study fate of colloids in soils but was the less sensitive one. Ag(0) labeling with ICP-MS detection was found to be very sensitive to measure deposition profiles. Radiolabeled ((110m)Ag(0)) nanoparticles permitted in situ detection. Results obtained with radiolabeled nanoparticles are wholly original and might be used for improving the modeling of deposition and release dynamics.

  10. Detection of occlusal carious lesions: an in vitro comparison of clinicians' diagnostic abilities at varying levels of experience.

    PubMed

    Swenson, Eric; Hennessy, Bernard

    2009-01-01

    There are many different methods available for detecting occlusal caries. This in vitro study, performed on 94 extracted human teeth, examines differences in diagnostic abilities (using visual and tactile methods) and examines restorative choices among 21 dental clinicians, based on amount of clinical experience. Test subjects examined the extracted teeth and utilized a mirror explorer, bitewing radiographs, and magnification to diagnose suspected occlusal caries. The teeth were sectioned and diagnosed macroscopically to obtain a sensitivity and specificity value for each clinician. Based on the results, there is no strong correlation between a dentist's amount of experience and a more accurate diagnosis or more conservative treatment options.

  11. External validity of Concealed Information Test experiment: Comparison of respiration, skin conductance, and heart rate between experimental and field card tests.

    PubMed

    Zaitsu, Wataru

    2016-07-01

    The Concealed Information Test (CIT) is a memory detection method based on an examinee's physiological responses to crime-relevant items (critical items) in comparison with crime-irrelevant items (noncritical items). I examined the external validity of CIT laboratory experiments by comparing respiratory speed (RS), skin conductance response (SCR), and heart rate (HR) between a laboratory experiment (n = 30) and a field test (n = 30) in a card test. A linear mixed models analysis showed that the critical items in both CIT contexts elicited CIT effects: RS repression, SCR increase, and HR deceleration. Additionally, the critical items in the field elicited a larger RS suppression than those in the laboratory; however, SCR and HR on the critical items showed no statistical differences between the laboratory and field CITs. Moreover, the tonic HRs in the field tests were higher than in the CIT experiments, but there were no significant correlations between the tonic HR and each CIT effect in RS, SCR, and HR. These results suggested that CIT detection efficiency was not affected by arousal levels and may imply that the CIT effects observed with RS, SCR, and HR in the CIT laboratory experiments has adequate external validity and can be generalized to the CIT field. PMID:27031043

  12. External validity of Concealed Information Test experiment: Comparison of respiration, skin conductance, and heart rate between experimental and field card tests.

    PubMed

    Zaitsu, Wataru

    2016-07-01

    The Concealed Information Test (CIT) is a memory detection method based on an examinee's physiological responses to crime-relevant items (critical items) in comparison with crime-irrelevant items (noncritical items). I examined the external validity of CIT laboratory experiments by comparing respiratory speed (RS), skin conductance response (SCR), and heart rate (HR) between a laboratory experiment (n = 30) and a field test (n = 30) in a card test. A linear mixed models analysis showed that the critical items in both CIT contexts elicited CIT effects: RS repression, SCR increase, and HR deceleration. Additionally, the critical items in the field elicited a larger RS suppression than those in the laboratory; however, SCR and HR on the critical items showed no statistical differences between the laboratory and field CITs. Moreover, the tonic HRs in the field tests were higher than in the CIT experiments, but there were no significant correlations between the tonic HR and each CIT effect in RS, SCR, and HR. These results suggested that CIT detection efficiency was not affected by arousal levels and may imply that the CIT effects observed with RS, SCR, and HR in the CIT laboratory experiments has adequate external validity and can be generalized to the CIT field.

  13. Assessing the effects of cognitive experiments on the welfare of captive chimpanzees (Pan troglodytes) by direct comparison of activity budget between wild and captive chimpanzees.

    PubMed

    Yamanashi, Yumi; Hayashi, Misato

    2011-12-01

    We investigated the effects of cognitive experiments by direct comparison of activity budgets between wild and captive chimpanzees. One goal of captive management is to ensure that the activity budgets of captive animals are as similar as possible to those of their wild counterparts. However, such similarity has rarely been achieved. We compared the activity budget among three groups of chimpanzees: wild chimpanzees in Bossou (Guinea, n = 10), and captive chimpanzees who participated in cognitive experiments (experimental chimpanzees, n = 6) or did not participate in the experiments (nonexperimental chimpanzees, n = 6) at the Primate Research Institute (Japan). The experimental chimpanzees voluntarily participated in computer-controlled cognitive tasks and small pieces of fruits were provided as rewards. The data from captivity were obtained on the experimental days (weekdays) and nonexperimental days (weekends). In both study sites, we followed each chimpanzee from about 7 a.m. until the time when chimpanzees started to rest in the evening. The behaviors were recorded every 1 min. The results showed that on weekdays, feeding time and resting time of the experimental chimpanzees were almost the same as those of wild chimpanzees. However, for the nonexperimental chimpanzees, feeding time was significantly shorter and resting time was longer than those of the wild chimpanzees. In contrast, no difference was found in feeding time or resting time of the two groups of captive chimpanzees on weekends. The results suggested that the cognitive experiments worked as an efficient method for food-based enrichment.

  14. The Influence of Reasons for Attending University on University Experience: A Comparison between Students with and without Disabilities

    ERIC Educational Resources Information Center

    Reed, Maureen J.; Kennett, Deborah J.; Emond, Marc

    2015-01-01

    Students choose to go to university for many reasons. They include those with disabilities and those without. The reasons why students with disabilities go to university and how these reasons impact university experience, including coping (academic resourcefulness), adapting, academic ability beliefs (academic self-efficacy), and grades, are…

  15. Adolescents' Psychological Response to the Experience of Community Interpersonal Violence: A Cross-National and a Cross-Cultural Comparison

    ERIC Educational Resources Information Center

    Rosenthal, Beth Spenciner; Wilson, W. Cody

    2006-01-01

    A comparative cross-national study investigating the level of experience with community interpersonal violence, level of psychological distress, and the relationship between exposure and distress among adolescents is presented. Participants were 617 first-year college students comprising African Americans and Jamaican Americans living in New York…

  16. Examining the Internal Validity and Statistical Precision of the Comparative Interrupted Time Series Design by Comparison with a Randomized Experiment

    ERIC Educational Resources Information Center

    St.Clair, Travis; Cook, Thomas D.; Hallberg, Kelly

    2014-01-01

    Although evaluators often use an interrupted time series (ITS) design to test hypotheses about program effects, there are few empirical tests of the design's validity. We take a randomized experiment on an educational topic and compare its effects to those from a comparative ITS (CITS) design that uses the same treatment group as the…

  17. A Comparison of Supervised Occupational Experience Programs Conducted by Males and Females in Wyoming. A Report of Research.

    ERIC Educational Resources Information Center

    Reynolds, Carl L.

    A study was conducted in Wyoming to determine the scope and economic value of supervised occupational experience programs (SOEPs) in vocational agriculture. The study tried to determine the level of participation and success realized by females engaged in SOEP activities, and to find out to what degree males and females engage in balanced SOEPs,…

  18. Childhood Experiences of Sexual Abuse and Later Parenting Practices among Non-Offending Mothers of Sexually Abused and Comparison Girls

    ERIC Educational Resources Information Center

    Kim, Kihyun; Trickett, Penelope K.; Putnam, Frank W.

    2010-01-01

    Objective: The primary goal of this study was to explore the relationship between childhood sexual abuse and parenting practices among non-offending mothers of sexually abused girls. Guided by a developmental-ecological perspective of parenting, several models with different potential pathways starting from the mothers' childhood experiences of…

  19. Comparison of experimental data and 3D simulations of ion beam neutralization from the neutralized transport experiment

    SciTech Connect

    Thoma, C.; Welch, D.R.; Yu, S.S.; Henestroza, E.; Roy, P.K.; Eylon, S.; Gilson, E.P.

    2004-09-22

    The Neutralized Transport Experiment (NTX) at Lawrence Berkeley National Laboratory has been designed to study the final focus and neutralization of high perveance ion beams for applications in heavy ion fusion (HIF) and high energy density physics (HEDP) experiments. Pre-formed plasmas in the last meter before the target of the scaled experiment provide a source of electrons which neutralize the ion current and prevent the space-charge induced spreading of the beam spot. NTX physics issues are discussed and experimental data is analyzed and compared with 3D particle-in-cell simulations. Along with detailed target images, 4D phase-space data of the NTX at the entrance of the neutralization region has been acquired. This data is used to provide a more accurate beam distribution with which to initialize the simulation. Previous treatments have used various idealized beam distributions which lack the detailed features of the experimental ion beam images. Simulation results are compared with NTX experimental measurements for 250 keV K{sup +} ion beams with dimensionless perveance of 1-7 x 10{sup -4}. In both simulation and experiment, the deduced beam charge neutralization is close to the predicted maximum value.

  20. A Comparison of the Concepts of Democracy and Experience in a Sample of Major Works by Dewey and Freire

    ERIC Educational Resources Information Center

    Shyman, Eric

    2011-01-01

    While theorizing in distinctly different times, distinctly different cultures, and under distinctly different circumstances, notable philosophical similarities can be drawn between John Dewey and Paulo Freire. This article focuses on two major themes evident in a sample of each philosopher's major works, democracy and experience, and draws…

  1. A Comparison of the First-Year Experience Programming to Enhance the Retention of Future Allied Health Professionals

    ERIC Educational Resources Information Center

    Whalen, Tina Forsythe

    2012-01-01

    This mixed-methods case study examined the effectiveness of a new first-year experience (FYE) curriculum for selected Choose Ohio First Scholars in the College of Allied Health Sciences (CAHS) and compared it with the effectiveness of the traditional FYE curriculum in CAHS. The quantitative phase of the study involved the collection and analysis…

  2. Visualization of jet flows over a plate by pressure-sensitive paint experiments and comparison with CFD.

    PubMed

    Fujii, Kozo; Tsuboi, Nobuyuki; Fujimatsu, Nobuyoshi

    2002-10-01

    Flow fields created by underexpanded sonic jets impinging on an inclined flat plate were studied experimentally using the pressure sensitive paint (PSP) measurement technique. The measurement system and some representative results are presented here. Two binders, thin-layer chromatography (TLC) plates and anodized aluminum (A-A) plates were tested with bathophen ruthenium chloride as a luminophore. The results show that both the binders can be used. TLC plates are preferable because their luminescent intensity is almost twice that of the A-A plates. Quantitative measurements require accurate temperature calibration. A preliminary effort to elucidate the flow structure by combining the PSP results with a computer simulation of the same flow field is presented. Although good agreement is obtained between the experimental and numerical results, future quantitative comparisons are necessary to yield a useful tool in the analysis of the jet-plate interaction flows.

  3. A comparison of cervical histopathology variability using whole slide digitized images versus glass slides: experience with a statewide registry.

    PubMed

    Gage, Julia C; Joste, Nancy; Ronnett, Brigette M; Stoler, Mark; Hunt, William C; Schiffman, Mark; Wheeler, Cosette M

    2013-11-01

    Whole slide imaging is increasingly used for primary and consultative diagnoses, teaching, telepathology, slide sharing, and archiving. We compared pathologist evaluations of glass slides and corresponding digitized images within the context of a statewide surveillance effort. Cervical specimens collected by the New Mexico HPV Pap Registry research program targeted cases diagnosed between 2006 and 2010. Two samples of 250 slides each were digitized with the ScanScope XT (Aperio, Vista, CA) microscope and reviewed with Aperio ImageScope reader. (1) A "random set" had a distribution of community diagnoses: 70% from cases of cervical intraepithelial neoplasia grade 2 or higher, 20% from cases of cervical intraepithelial neoplasia grade 1 and 10% from negative cases. (2) A "discrepant set" was represented by difficult cases where 2 study pathologists initially disagreed. Within the regular workflow of the New Mexico HPV Pap Registry, 3 pathologists read the slides 2 to 3 times each without knowledge of clinical history, previous readings or sampling scheme. Pathologists also read each corresponding image twice. For within- and between-reader comparisons we calculated unweighted κ statistics and asymmetry χ(2) tests. Across all comparisons, slides and images yielded similar results. For the random set, almost all within-reader and between-reader Kappa values ranged between 0.7 and 0.8 and 0.6 and 0.7, respectively. For the discrepant set, most within- and between-reader κ values were 0.4 to 0.6. As cervical intraepithelial neoplasia diagnostic terminology changes, pathologists may need to re-read histopathology slides to compare disease trends over time, eg, before/after introduction of human papillomavirus vaccination. Diagnosis of cervical intraepithelial neoplasia differed little between slides and corresponding digitized images. PMID:24075599

  4. Biodegradation of the surfactant linear alkylbenzenesulfonate in sewage- contaminated groundwater: A comparison of column experiments and field tracer tests

    USGS Publications Warehouse

    Krueger, C.J.; Radakovich, K.M.; Sawyer, T.E.; Barber, L.B.; Smith, R.L.; Field, J.A.

    1998-01-01

    Transport and biodegradation of linear alkylbenzenesulfonate (LAS) in sewage-contaminated groundwater were investigated for a range of dissolved oxygen concentrations. Both laboratory column and an 80-day continuous injection tracer test field experiments were conducted. The rates of LAS biodegradation increased with increasing dissolved oxygen concentrations and indicated the preferential biodegradation of the longer alkyl chain LAS homologues (i.e., C12 and C13) and external isomers (i.e., 2-and 3- phenyl). However, for similar dissolved oxygen concentrations, mass removal rates for LAS generally were 2-3 times greater in laboratory column experiments than in the field tracer test. Under low oxygen conditions (<1 mg/L) only a fraction of the LAS mixture biodegraded in both laboratory and field experiments. Biodegradation rate constants for the continuous injection field test (0.002-0.08 day-1) were comparable to those estimated for a 3-h injection (pulsed) tracer test conducted under similar biogeochemical conditions, indicating that increasing the exposure time of aquifer sediments to LAS did not increase biodegradation rates.Transport and biodegradation of linear alkylbenzenesulfonate (LAS) in sewage-contaminated groundwater were investigated for a range of dissolved oxygen concentrations. Both laboratory column and an 80-day continuous injection tracer test field experiments were conducted. The rates of LAS biodegradation increased with increasing dissolved oxygen concentrations and indicated the preferential biodegradation of the longer alkyl chain LAS homologues (i.e., C12 and C13) and external isomers (i.e., 2- and 3-phenyl). However, for similar dissolved oxygen concentrations, mass removal rates for LAS generally were 2-3 times greater in laboratory column experiments than in the field tracer test. Under low oxygen conditions (<1 mg/L) only a fraction of the LAS mixture biodegraded in both laboratory and field experiments. Biodegradation rate constants

  5. Feature-scale model of Si etching in SF{sub 6} plasma and comparison with experiments

    SciTech Connect

    Belen, Rodolfo Jun; Gomez, Sergi; Kiehlbauch, Mark; Cooperberg, David; Aydil, Eray S.

    2005-01-01

    We have developed a semiempirical feature scale model of Si etching in SF{sub 6} plasma, which incorporates the addition of small amounts of O in the discharge coming from the etching of the oxide mask and quartz window. The degrees of freedom in the model are reduced by using information from plasma diagnostics and previously published data to estimate the ion flux, the ion energy and angle distributions, and the relative F and O fluxes. Experimentally inaccessible parameters such as the F sticking coefficient, chemical etch rate constant, and the ion-enhanced etch yield are determined by matching simulated feature profiles with those obtained from carefully designed etching experiments. Excellent agreement between experiments and simulations is obtained.

  6. Rayleigh-Taylor instability-induced mixing: initial conditions modeling, three-dimensional simulations and comparisons with experiment

    SciTech Connect

    Mueschke, N; Schilling, O; Andrews, M

    2007-01-09

    A spectral/compact finite-difference method with a third-order Adams-Bashforth-Moulton time-evolution scheme is used to perform a direct numerical simulation (DNS) of Rayleigh-Taylor flow. The initial conditions are modeled by parameterizing the multi-mode velocity and density perturbations measured just off of the splitter plate in water channel experiments. Parameters in the DNS are chosen to match the experiment as closely as possible. The early-time transition from a weakly-nonlinear to a strongly-nonlinear state, as well as the onset of turbulence, is examined by comparing the DNS and experimental results. The mixing layer width, molecular mixing parameter, vertical velocity variance, and density variance spectrum obtained from the DNS are shown to be in good agreement with the corresponding experimental values.

  7. A comparison of two factorial designs, a complete 3 x 3 factorial and a central composite rotatable design, for use in binomial response experiments in aquatic toxicology.

    PubMed

    Edginton, Andrea N; Sheridan, Patrick M; Boermans, Herman J; Thompson, Dean G; Holt, John D; Stephenson, Gerald R

    2004-02-01

    Using an amphibian toxicity testing protocol, comparative studies were conducted to assess the predictive precision, degree of similarity of results and efficiency of a central composite rotatable design (CCRD) in relation to a conventional complete 3x3 factorial design. Data were treated with response surface analysis using generalized linear models (glm) and application of profile deviance to generate confidence intervals. Design comparisons were based on studies conducted using the Frog Embryo Teratogenesis Assay-Xenopus (FETAX) protocol to examine the interaction of three toxicants at pH levels ranging from 4.5 to 8.5. Test substances included two commercial herbicide formulations based on glyphosate ([N-phosphonomethyl]glycine) isopropylamine salt (Vision, Rodeo) as well as a polyethoxylated tallow amine surfactant blend (MON 0818), which is a key component of the Vision formulation. The generated models from both the CCRD and the factorial designs produced toxicity estimates similar to each other and to previously published results. Trends were also similar to published results in that the surfactant, MON 0818, was comparatively more toxic than Vision, which was more toxic than Rodeo. Further, all toxicants induced higher mortality under alkaline as opposed to acidic conditions. The CCRD was between 66 and 124% more efficient in the Vision and Rodeo experiments in comparison to the complete 3x3 factorial. Thus, the factorial experiment would have required at least 66% more observations to obtain the same precision. There appeared to be no efficiency gain with the use of the CCRD for MON 0818. The CCRD had tighter confidence intervals in 9 of 12 cases across all test substances. Computer simulations using the experimental data for Vision demonstrated that the LCalpha estimates generated from the 1,000 simulated data sets were very close to the "true" value for both designs. This was based on small bias and mean squared error calculations. Coverage

  8. Cosmological results from the Planck space mission and their comparison with data from the WMAP and BICEP2 experiments

    NASA Astrophysics Data System (ADS)

    Verkhodanov, O. V.

    2016-01-01

    We review basic results from the European Space Agency's Planck space mission, which are of crucial significance to understanding the origin and evolution of the Universe. The main stages of astrophysical and cosmological data processing pipelines are considered. The Planck results are compared with the data from the NASA WMAP (Wilkinson Microwave Anisotropy Probe) space mission and the BICEP2 (Background Imaging of Cosmic Extragalactic Polarization 2) experiment.

  9. PHITS simulations of the Protective curtain experiment onboard the Service module of ISS: Comparison with absorbed doses measured with TLDs

    NASA Astrophysics Data System (ADS)

    Ploc, Ondřej; Sihver, Lembit; Kartashov, Dmitry; Shurshakov, Vyacheslav; Tolochek, Raisa

    2013-12-01

    "Protective curtain" was the physical experiment onboard the International Space Station (ISS) aimed on radiation measurement of the dose - reducing effect of the additional shielding made of hygienic water-soaked wipes and towels placed on the wall in the crew cabin of the Service module Zvezda. The measurements were performed with 12 detector packages composed of thermoluminescent detectors (TLDs) and plastic nuclear track detectors (PNTDs) placed at the Protective curtain, so that they created pairs of shielded and unshielded detectors.

  10. Understanding how deployment experiences change over time: Comparison of female and male OEF/OIF and Gulf War veterans.

    PubMed

    Fox, Annie B; Walker, Brian E; Smith, Brian N; King, Daniel W; King, Lynda A; Vogt, Dawne

    2016-03-01

    Despite increased attention to the evolving nature of war, the unique challenges of contemporary deployment, and women's changing role in warfare, few studies have examined differences in deployment stressors across eras of service or evaluated how gender differences in deployment experiences have changed over time. Using data collected from two national survey studies, we examined war cohort and gender differences in veterans' reports of both mission-related and interpersonal stressors during deployment. Although Operation Enduring Freedom and Operation Iraqi Freedom veterans reported more combat experiences and greater preparedness for deployment compared to Gulf War veterans, Gulf War veterans reported higher levels of other mission-related stressors, including difficult living and working environment, perceived threat, and potential exposure to nuclear, biological, and chemical weapons. Gender differences also emerged, with men reporting greater exposure to mission-related stressors and women reporting higher levels of interpersonal stressors. However, the size and nature of gender differences did not differ significantly when comparing veterans of the two eras. By understanding how risk factors for PTSD differ based on war era and gender, veterans' experiences can be better contextualized. PMID:25866959

  11. Comparison of Laboratory and Modeling Results for High Strain Rates in Support of the Source Physics Experiment

    NASA Astrophysics Data System (ADS)

    Sussman, A.; Rougier, E.; Broome, S.; Knight, E.; Pfeifle, T.; Schultz-Fellenz, E. S.

    2011-12-01

    The Source Physics Experiment program, conducted in Climax Stock Granite at the Nevada Test Site, will provide ground truth data to create and improve strong ground motion and seismic S-wave generation and propagation models. Modeling using advanced simulation codes will be performed both a priori and after each experiment; a key component in the predictive capability and ultimate validation of the models is the full understanding of the intervening geology between the source and instrumented bore holes including the geomechanical behavior of the site rock/structural features. Mechanical properties determined via laboratory testing of site rocks leads to the parameterization of constitutive models used in the simulations. The combined finite-discrete element method by Munjiza is an excellent tool to address a wide range of problems involving fracturing and fragmentation of solids and has been applied to many complex rock mechanics problems such as block caving, deep mining techniques, rock blasting, and seismic wave propagation. Since most of the problems involving fracture and fragmentation of solids are three dimensional, an improved 2D/3D FEM/DEM capability has been developed at Los Alamos National Laboratory. In this paper, Split Hopkinson Pressure Bar experiments, performed on the Climax Stock Granite by Sandia National Laboratories, are simulated using this improved 2D/3D FEM/DEM approach, implemented on LANL's MUNROU (Munjiza-Rougier) code and show excellent agreement.

  12. Overall scores as an alternative to global ratings in patient experience surveys; a comparison of four methods

    PubMed Central

    2013-01-01

    Background Global ratings of healthcare by patients are a popular way of summarizing patients’ experiences. Summary scores can be used for comparing healthcare provider performance and provider rankings. As an alternative, overall scores from actual patient experiences can be constructed as summary scores. This paper addresses the statistical and practical characteristics of overall scores as an alternative to a global rating in summarizing patient survey results. Methods Data from a 2010 patient experience survey for approximately 12,000 nursing home residents (7.5% of all Dutch nursing home residents at the time) from 464 nursing homes in the Netherlands (25% of the Dutch nursing homes) was used. Data was collected through specifically designed standardized interview surveys. The respondents’ scores for 15 established quality indicators (or composites) for nursing home care were used to calculate overall scores for each nursing home, using four different strategies. The characteristics of the overall scores were compared against each other and with the respondents’ global rating. Results The individual indicators showed stronger associations with each of the four overall strategies than with the global ratings. Furthermore, the dispersion of the overall scores across nursing homes was greater. Differences between overall scores appeared limited. Conclusions Overall scores proved more valid than global ratings as a summary of the indicator scores, and also showed more pronounced differences between nursing homes. Because of the limited statistical differences between the strategies, and for practical reasons, a straightforward averaging of quality indicator scores may be preferred as an overall score. PMID:24245726

  13. Ultrafast Charge-Transfer Dynamics at the Boron Subphthalocyanine Chloride/C60 Heterojunction: Comparison between Experiment and Theory.

    PubMed

    Wilcox, Daniel E; Lee, Myeong H; Sykes, Matthew E; Niedringhaus, Andrew; Geva, Eitan; Dunietz, Barry D; Shtein, Max; Ogilvie, Jennifer P

    2015-02-01

    Photoinduced charge-transfer (CT) processes play a key role in many systems, particularly those relevant to organic photovoltaics and photosynthesis. Advancing the understanding of CT processes calls for comparing their rates measured via state-of-the-art time-resolved interface-specific spectroscopic techniques with theoretical predictions based on first-principles molecular models. We measure charge-transfer rates across a boron subphthalocyanine chloride (SubPc)/C60 heterojunction, commonly used in organic photovoltaics, via heterodyne-detected time-resolved second-harmonic generation. We compare these results to theoretical predictions based on a Fermi's golden rule approach, with input parameters obtained using first-principles calculations for two different equilibrium geometries of a molecular donor-acceptor in a dielectric continuum model. The calculated rates (∼2 ps(-1)) overestimate the measured rates (∼0.1 ps(-1)), which is consistent with the expectation that the calculated rates represent an upper bound over the experimental ones. The comparison provides valuable understanding of how the structure of the electron donor-acceptor interface affects the CT kinetics in organic photovoltaic systems. PMID:26261981

  14. Ultrafast Charge-Transfer Dynamics at the Boron Subphthalocyanine Chloride/C60 Heterojunction: Comparison between Experiment and Theory.

    PubMed

    Wilcox, Daniel E; Lee, Myeong H; Sykes, Matthew E; Niedringhaus, Andrew; Geva, Eitan; Dunietz, Barry D; Shtein, Max; Ogilvie, Jennifer P

    2015-02-01

    Photoinduced charge-transfer (CT) processes play a key role in many systems, particularly those relevant to organic photovoltaics and photosynthesis. Advancing the understanding of CT processes calls for comparing their rates measured via state-of-the-art time-resolved interface-specific spectroscopic techniques with theoretical predictions based on first-principles molecular models. We measure charge-transfer rates across a boron subphthalocyanine chloride (SubPc)/C60 heterojunction, commonly used in organic photovoltaics, via heterodyne-detected time-resolved second-harmonic generation. We compare these results to theoretical predictions based on a Fermi's golden rule approach, with input parameters obtained using first-principles calculations for two different equilibrium geometries of a molecular donor-acceptor in a dielectric continuum model. The calculated rates (∼2 ps(-1)) overestimate the measured rates (∼0.1 ps(-1)), which is consistent with the expectation that the calculated rates represent an upper bound over the experimental ones. The comparison provides valuable understanding of how the structure of the electron donor-acceptor interface affects the CT kinetics in organic photovoltaic systems.

  15. Simulation of real-gas effects on pressure distributions for aeroassist flight experiment vehicle and comparison with prediction

    NASA Technical Reports Server (NTRS)

    Micol, John R.

    1992-01-01

    Pressure distributions measured on a 60 degree half-angle elliptic cone, raked off at an angle of 73 degrees from the cone centerline and having an ellipsoid nose (ellipticity equal to 2.0 in the symmetry plane) are presented for angles of attack from -10 degrees to 10 degrees. The high normal shock density ratio aspect of a real gas was simulated by testing in Mach 6 air and CF sub 4 (density ratio equal to 5.25 and 12.0, respectively). The effects of Reynolds number, angle of attack, and normal shock density ratio on these measurements are examined, and comparisons with a three dimensional Euler code known as HALIS are made. A significant effect of density ratio on pressure distributions on the cone section of the configuration was observed; the magnitude of this effect decreased with increasing angle of attack. The effect of Reynolds number on pressure distributions was negligible for forebody pressure distributions, but a measurable effect was noted on base pressures. In general, the HALIS code accurately predicted the measured pressure distributions in air and CF sub 4.

  16. Comparison of entrainment rates from a tank experiment with results using the one-dimensional turbulence model.

    SciTech Connect

    Kerstein, Alan R.; Sayler, B. J.; Wunsch, S.; Schmidt, H.; Nedelec, R.

    2010-05-01

    Recent work suggests that cloud effects remain one of the largest sources of uncertainty in model-based estimates of climate sensitivity. In particular, the entrainment rate in stratocumulus-topped mixed layers needs better models. More than thirty years ago a clever laboratory experiment was conducted by McEwan and Paltridge to examine an analog of the entrainment process at the top of stratiform clouds. Sayler and Breidenthal extended this pioneering work and determined the effect of the Richardson number on the dimensionless entrainment rate. The experiments gave hints that the interaction between molecular effects and the one-sided turbulence seems to be crucial for understanding entrainment. From the numerical point of view large-eddy simulation (LES) does not allow explicitly resolving all the fine scale processes at the entrainment interface. Direct numerical simulation (DNS) is limited due to the Reynolds number and is not the tool of choice for parameter studies. Therefore it is useful to investigate new modeling strategies, such as stochastic turbulence models which allow sufficient resolution at least in one dimension while having acceptable run times. We will present results of the One-Dimensional Turbulence stochastic simulation model applied to the experimental setup of Sayler and Breidenthal. The results on radiatively induced entrainment follow quite well the scaling of the entrainment rate with the Richardson number that was experimentally found for a set of trials. Moreover, we investigate the influence of molecular effects, the fluids optical properties, and the artifact of parasitic turbulence experimentally observed in the laminar layer. In the simulations the parameters are varied systematically for even larger ranges than in the experiment. Based on the obtained results a more complex parameterization of the entrainment rate than currently discussed in the literature seems to be necessary.

  17. Investigation of coupling mechanisms in attosecond transient absorption of autoionizing states: comparison of theory and experiment in xenon

    NASA Astrophysics Data System (ADS)

    Li, Xuan; Bernhardt, Birgitta; Beck, Annelise R.; Warrick, Erika R.; Pfeiffer, Adrian N.; Justine Bell, M.; Haxton, Daniel J.; McCurdy, C. William; Neumark, Daniel M.; Leone, Stephen R.

    2015-06-01

    Attosecond transient absorption spectra near the energies of autoionizing states are analyzed in terms of the photon coupling mechanisms to other states. In a recent experiment, the autoionization lifetimes of highly excited states of xenon were determined and compared to a simple expression based on a model of how quantum coherence determines the decay of a metastable state in the transient absorption spectrum. Here it is shown that this procedure for extracting lifetimes is more general and can be used in cases involving either resonant or nonresonant coupling of the attosecond-probed autoionizing state to either continua or discrete states by a time-delayed near infrared (NIR) pulse. The fits of theoretically simulated absorption signals for the 6p resonance in xenon (lifetime = 21.1 fs) to this expression yield the correct decay constant for all the coupling mechanisms considered, properly recovering the time signature of twice the autoionization lifetime due to the coherent nature of the transient absorption experiment. To distinguish between these two coupling cases, the characteristic dependencies of the transient absorption signals on both the photon energy and time delay are investigated. Additional oscillations versus delay-time in the measured spectrum are shown and quantum beat analysis is used to pinpoint the major photon-coupling mechanism induced by the NIR pulse in the current xenon experiment: the NIR pulse resonantly couples the attosecond-probed state, 6p, to an intermediate 8s (at 22.563 eV), and this 8s state is also coupled to a neighboring state (at 20.808 eV).

  18. Deployment Experiences, Social Support, and Mental Health: Comparison of Black, White, and Hispanic U.S. Veterans Deployed to Afghanistan and Iraq.

    PubMed

    Muralidharan, Anjana; Austern, David; Hack, Samantha; Vogt, Dawne

    2016-06-01

    Compared to their White counterparts, Black and Hispanic Vietnam-era, male, combat veterans in the United States have experienced discrimination and increased trauma exposure during deployment and exhibited higher rates of postdeployment mental health disorders. The present study examined differences in deployment experiences and postdeployment mental health among male and female Black, Hispanic, and White veterans deployed in support of Operation Enduring Freedom in Afghanistan and Operation Iraqi Freedom in Iraq. Data were drawn from a national survey of veterans (N = 924) who had returned from deployment within the last 2 years. Ethnoracial minority veterans were compared to White veterans of the same gender on deployment experiences and postdeployment mental health. The majority of comparisons did not show significant differences; however, several small group differences did emerge (.02 < η(2) < .04). Ethnoracial minority veterans reported greater perceived threat in the warzone and more family-related concerns and stressors during deployment than White veterans of the same gender. Minority female veterans reported higher levels of postdeployment symptoms of anxiety than their White counterparts, which were accounted for by differences in deployment experience. These differences call for ongoing monitoring. PMID:27191777

  19. Deployment Experiences, Social Support, and Mental Health: Comparison of Black, White, and Hispanic U.S. Veterans Deployed to Afghanistan and Iraq.

    PubMed

    Muralidharan, Anjana; Austern, David; Hack, Samantha; Vogt, Dawne

    2016-06-01

    Compared to their White counterparts, Black and Hispanic Vietnam-era, male, combat veterans in the United States have experienced discrimination and increased trauma exposure during deployment and exhibited higher rates of postdeployment mental health disorders. The present study examined differences in deployment experiences and postdeployment mental health among male and female Black, Hispanic, and White veterans deployed in support of Operation Enduring Freedom in Afghanistan and Operation Iraqi Freedom in Iraq. Data were drawn from a national survey of veterans (N = 924) who had returned from deployment within the last 2 years. Ethnoracial minority veterans were compared to White veterans of the same gender on deployment experiences and postdeployment mental health. The majority of comparisons did not show significant differences; however, several small group differences did emerge (.02 < η(2) < .04). Ethnoracial minority veterans reported greater perceived threat in the warzone and more family-related concerns and stressors during deployment than White veterans of the same gender. Minority female veterans reported higher levels of postdeployment symptoms of anxiety than their White counterparts, which were accounted for by differences in deployment experience. These differences call for ongoing monitoring.

  20. Spin-density correlations in the dynamic spin-fluctuation theory: Comparison with polarized neutron scattering experiments

    NASA Astrophysics Data System (ADS)

    Melnikov, N. B.; Reser, B. I.; Paradezhenko, G. V.

    2016-08-01

    To study the spin-density correlations in the ferromagnetic metals above the Curie temperature, we relate the spin correlator and neutron scattering cross-section. In the dynamic spin-fluctuation theory, we obtain explicit expressions for the effective and local magnetic moments and spatial spin-density correlator. Our theoretical results are demonstrated by the example of bcc Fe. The effective and local moments are found in good agreement with results of polarized neutron scattering experiment over a wide temperature range. The calculated short-range order is small (up to 4 Å) and slowly decreases with temperature.

  1. Comparison of velocity and temperature time series data analysis in experiments on the thermally driven rotating annulus

    NASA Astrophysics Data System (ADS)

    von Larcher, Thomas; Harlander, Uwe; Alexandrov, Kiril; Wang, Yongtai

    2010-05-01

    The model of the differentially heated, rotating cylindrical gap filled with a fluid is since more than four decades extensively used for laboratory experiments of baroclinic wave interactions, and a number of data acquisition techniques are applied e.g. to unhide regular waves of different zonal wave number, to better understand the transition to the quasi-chaotic regime, and to reveal the underlying dynamical processes of complex wave flows. In our experiments presented here, we make use of non-intrusive measurement techniques of a quite different nature. While the high accurate Laser-Doppler-Velocimetry (LDV ) is used for measurements of the radial velocity component at equidistant azimuthal positions, a high sensitive thermographic camera, which resolution allows for resolving fine scale structures, measures the surface temperature field. Both sets of time series data are analyzed by using multivariate statistical techniques. While the LDV data sets are studied by applying the Multi-Channel Singular Spectrum Analysis (M - SSA), the temperature data sets are analyzed by applying the Empirical Orthogonal Functions (EOF ). In addition, the temperature data are processed in a way to become comparable to the LDV data, i.e. reducing the size of the data set in such a manner that the temperature measurements would imaginary be performed at equidistant azimuthal positions only. This approach initially results in a great loss of information. But applying the M - SSA to the reduced temperature data sets enable us not only to compare the data analysis methods but also to reclassify the results yielded with the LDV data analysis. The measurements are performed at particular parameter points, where our former studies show that kinds of complex wave patterns occur [1, 2]. For example, we found a dominant and a weak mode in the 3-4 wave transition region. This finding confirms earlier ideas on wave dispersion in transition regions between regular waves. Increasing the annulus

  2. A comparison of food safety knowledge among restaurant managers, by source of training and experience, in Oklahoma County, Oklahoma.

    PubMed

    Lynch, Robert A; Elledge, Brenda L; Griffith, Charles C; Boatright, Daniel T

    2003-09-01

    The annual incidence of illness related to food consumption continues to present a challenge to environmental health management. A significant fraction of cases have been attributed to consumption of food in restaurants, and as the number of meals eaten away from the home continues to rise, the potential for large-scale foodborne-disease outbreaks will continue to increase. Food handlers in retail establishments contribute to the incidence of foodborne disease; therefore, it is essential that workers and management staff have a thorough understanding of safe food practices. Since the training, certification, and experience of food service managers vary greatly, it is also likely that managers' knowledge base may differ. In the study reported here, restaurant managers were administered a survey designed to measure their understanding of basic food safety principles. The sources of training, certification, and experience were found to significantly affect the level of food safety knowledge; however, increased hours of training did not increase knowledge. In addition, the time lapsed since training did not significantly affect the level of knowledge.

  3. Reactive ion etching of Si by Cl and Cl{sub 2} ions: Molecular dynamics simulations with comparisons to experiment

    SciTech Connect

    Hanson, D.E.; Kress, J.D.; Voter, A.F.

    1999-07-01

    We present results of molecular dynamics simulations of reactive ion etching (RIE) of a reconstructed Si(100)(2{times}1) surface. The existing Stillinger{endash}Weber interatomic potential for Si/Cl of Feil {ital et al.} has been modified by correcting the Si{endash}Si bond strength for a SiCl{sub n} moiety bound to a Si surface and the Si{endash}Cl bond strength in SiCl{sub m} molecules. This potential has been used to study RIE of Si by Cl and Cl{sub 2} ions. The calculated properties such as the Si yield, product stoichiometry, stoichiometry of the chlorosilyl surface, and Cl content of the chlorosilyl layer are in reasonable agreement with experiment. The dissociative chemisorption probability of Cl{sub 2} on Si(100)(2{times}1) as a function of energy has been simulated and the results are in reasonable agreement with experiment. {copyright} {ital 1999 American Vacuum Society.}

  4. Simulation of large particle transport near the surface under stable conditions: comparison with the Hanford tracer experiments

    NASA Astrophysics Data System (ADS)

    Kim, Eugene; Larson, Timothy

    A plume model is presented describing the downwind transport of large particles (1-100 μm) under stable conditions. The model includes both vertical variations in wind speed and turbulence intensity as well as an algorithm for particle deposition at the surface. Model predictions compare favorably with the Hanford single and dual tracer experiments of crosswind integrated concentration (for particles: relative bias=-0.02 and 0.16, normalized mean square error=0.61 and 0.14, for the single and dual tracer experiments, respectively), whereas the US EPA's fugitive dust model consistently overestimates the observed concentrations at downwind distances beyond several hundred meters (for particles: relative bias=0.31 and 2.26, mean square error=0.42 and 1.71, respectively). For either plume model, the measured ratio of particle to gas concentration is consistently overestimated when using the deposition velocity algorithm of Sehmel and Hodgson (1978. DOE Report PNL-SA-6721, Pacific Northwest Laboratories, Richland, WA). In contrast, these same ratios are predicted with relatively little bias when using the algorithm of Kim et al. (2000. Atmospheric Environment 34 (15), 2387-2397).

  5. Propagation of an electromagnetic wave in an absorbing anisotropic medium and infrared transmission of liquid crystals: comparison with experiments.

    PubMed

    Scaife, B K P; Sigarev, A A; Vij, J K; Goodby, J W

    2009-08-01

    The theory of the absorbance of a semi-infinite medium characterized by a second-rank dielectric tensor for the entire electromagnetic spectrum, as given by Scaife and Vij [J. Chem. Phys. 122, 174901 (2005)], is extended to include molecules of prolate spheriodal shape with longitudinal and transverse polarizabilities and to cover the case of elliptically polarized incident radiation. The theory is applied to the infrared transmission experiments of biaxial liquid crystals. It is found that the formula for the dependence on frequency and on angle of polarization of the absorbance A(omega,theta)= -log(10)[10(A(omega,0)) cos(2) theta + (10(-A(omega,pi/2)) sin(2) theta)] is unaffected by the anisotropy of the molecules and by the elliptical polarization of the incident radiation. A small (+/-5%) discrepancy between theory and experiment has been found for bands with high absorbances. It is found that this discrepancy does not depend on birefringence of the sample but may depend on the precise method of absorbance measurement and on effects at the surface of the cell containing the liquid crystal under test.

  6. Comparison of measured soft x-ray drive with shock and capsule implosion velocity for ignition tuning experiments on NIF

    NASA Astrophysics Data System (ADS)

    Kline, J.; Callahan, D.; Meezan, N.; Glenzer, S.; MacKinnon, A.; Dixit, S.; Kyrala, G.; Widmann, K.; Robey, H.; Clark, D.; Jones, O.; Hicks, D.; Celliers, P.; Farley, D.; Town, R.; Kalantar, D.; Dewald, E.; Moore, A.; Olson, R.; Doeppner, T.; Moody, J.; Ralph, J.; Thomas, C.; Landen, O.; Edwards, M.

    2011-10-01

    Indirect drive inertial confinement fusion experiments use high-Z hohlraums to convert laser energy to soft x-ray energy. The soft x-rays then drive the capsule via material ablation to compress the fuel payload and heat the central hot spot to initiate ignition. To achieve the highest fuel compression, a shaped radiation drive is used launching multiple shocks timed minimizes fuel entropy. The strength and velocity of these shocks depend directly on the radiation drive. The main laser pulse is then used to drive the implosion such that the PdV work can heat the central core to fusion conditions. To diagnose the soft x-ray drive in the hohlraum, Dante, an 18 channel soft x-ray spectrometer, measures the flux escaping the laser entrance hole. Measurements of this flux are used to assess the conditions for the capsule implosion. In this presentation, we will examine correlations between the soft x-ray measurements and shock velocity, as well as implosion velocity for recent ignition tuning experiments on NIF.

  7. Comparison between numerical simulation and visualization experiment on water behavior in single straight flow channel polymer electrolyte fuel cells

    NASA Astrophysics Data System (ADS)

    Masuda, Hiromitsu; Ito, Kohei; Oshima, Toshihiro; Sasaki, Kazunari

    A relationship between a flooding and a cell voltage drop for polymer electrolyte fuel cell was investigated experimentally and numerically. A visualization cell, which has single straight gas flow channel (GFC) and observation window, was fabricated to visualize the flooding in GFC. We ran the cell with changing operation condition, and measured the time evolution of cell voltage and took the images of cathode GFC. Considering the operation condition, we executed a developed numerical simulation, which is based on multiphase mixture model with a formulation on water transport through the surface of polymer electrolyte membrane and the interface of gas diffusion layer/GFC. As a result in experiment, we found that the cell voltage decreased with time and this decrease was accelerated by larger current and smaller air flow rate. Our simulation succeeded to demonstrate this trend of cell voltage. In experiment, we also found that the water flushing in GFC caused an immediate voltage change, resulting in voltage recovery or electricity generation stop. Although our simulation could not replicate this immediate voltage change, the supersaturated area obtained by our simulation well corresponded to fogging area appeared on the window surface in the GFC.

  8. The issue of multiple univariate comparisons in the context of neuroelectric brain mapping: an application in a neuromarketing experiment.

    PubMed

    Vecchiato, G; De Vico Fallani, F; Astolfi, L; Toppi, J; Cincotti, F; Mattia, D; Salinari, S; Babiloni, F

    2010-08-30

    This paper presents some considerations about the use of adequate statistical techniques in the framework of the neuroelectromagnetic brain mapping. With the use of advanced EEG/MEG recording setup involving hundred of sensors, the issue of the protection against the type I errors that could occur during the execution of hundred of univariate statistical tests, has gained interest. In the present experiment, we investigated the EEG signals from a mannequin acting as an experimental subject. Data have been collected while performing a neuromarketing experiment and analyzed with state of the art computational tools adopted in specialized literature. Results showed that electric data from the mannequin's head presents statistical significant differences in power spectra during the visualization of a commercial advertising when compared to the power spectra gathered during a documentary, when no adjustments were made on the alpha level of the multiple univariate tests performed. The use of the Bonferroni or Bonferroni-Holm adjustments returned correctly no differences between the signals gathered from the mannequin in the two experimental conditions. An partial sample of recently published literature on different neuroscience journals suggested that at least the 30% of the papers do not use statistical protection for the type I errors. While the occurrence of type I errors could be easily managed with appropriate statistical techniques, the use of such techniques is still not so largely adopted in the literature.

  9. The issue of multiple univariate comparisons in the context of neuroelectric brain mapping: an application in a neuromarketing experiment.

    PubMed

    Vecchiato, G; De Vico Fallani, F; Astolfi, L; Toppi, J; Cincotti, F; Mattia, D; Salinari, S; Babiloni, F

    2010-08-30

    This paper presents some considerations about the use of adequate statistical techniques in the framework of the neuroelectromagnetic brain mapping. With the use of advanced EEG/MEG recording setup involving hundred of sensors, the issue of the protection against the type I errors that could occur during the execution of hundred of univariate statistical tests, has gained interest. In the present experiment, we investigated the EEG signals from a mannequin acting as an experimental subject. Data have been collected while performing a neuromarketing experiment and analyzed with state of the art computational tools adopted in specialized literature. Results showed that electric data from the mannequin's head presents statistical significant differences in power spectra during the visualization of a commercial advertising when compared to the power spectra gathered during a documentary, when no adjustments were made on the alpha level of the multiple univariate tests performed. The use of the Bonferroni or Bonferroni-Holm adjustments returned correctly no differences between the signals gathered from the mannequin in the two experimental conditions. An partial sample of recently published literature on different neuroscience journals suggested that at least the 30% of the papers do not use statistical protection for the type I errors. While the occurrence of type I errors could be easily managed with appropriate statistical techniques, the use of such techniques is still not so largely adopted in the literature. PMID:20637802

  10. Nursing students' experiences with and strategic approaches to case-based instruction: a replication and comparison study between two disciplines.

    PubMed

    Demarco, Rosanna; Hayward, Lorna; Lynch, Marcia

    2002-04-01

    In the classroom and in clinical areas, knowing how to learn, reason, reflect, think creatively, generate and evaluate ideas, make decisions, and solve problems have been identified as key elements of critical thinking. However, to be successful in the current health care arena, caregivers cannot be satisfied with possessing the ability to solve problems and simply meet preestablished "outcomes" (Alfaro-LeFevre, 1998). It is necessary to improve knowledge and practice applications and to explore the best ways to do things within a work group. This qualitative study evaluated the experiences of senior-level nursing students using case-based instruction in a course titled, Leading and Managing in Nursing. It is a replication and extension (Phase II) of an original case-based instruction study, completed with senior physical therapy students (Phase I). Phase III of this study trajectory is the creation of an interdisciplinary case-based course that addresses either or both clinical collaborative care issues or leadership and management issues for health care profession students. From this Phase II study, six thematic groupings emerged as distinct student experiences in case-based instruction-motivation, real world, learning, knowledge development, emerging from within, and group dynamic issues.

  11. Characterization and comparison of seismic signals emitted during field scale sheer box experiments and artificially induced landslides

    NASA Astrophysics Data System (ADS)

    Yfantis, Georgios; Martinez Carvajal, Hernan Eduardo; Pytharouli, Stella; Lunn, Rebecca

    2014-05-01

    The identification and detection of landslide induced seismic signals, recorded by deployed seismometers on active landslides has been the subject of many studies. The most commonly faced problem is the uncertainty in identifying which of the recorded signals are representing a movement or a failure in the landslide's body. In this paper we present two novel experimental campaigns; 1) field scale laboratory experiments of a 65cm diameter sheer box, 2) artificially induced failure of two, two-meter high vertical soil slopes. Using a field scale sheer box we recorded seismic signals emitted during soil slippage events, a phenomenon observed at a landslide's failure plain. This was implemented by displacing, a few centimeters at a time (1-10cm), a concrete cylinder filled with soil along a corridor free from vegetation. The field scale sheer box methodology allows control over a large number of parameters that affect a landslide. For example, it is possible to control soil saturation thus simulating different rain events or control the stress field on the soil's slippage surface simulating displacement events at different depths. More than 40 displacement events were induced under four different loading conditions between 472kg to 829kg. All soil slippage events were recorded above the levels of background seismic noise. Repetition of the methodology under the same experimental conditions resulted in similar seismic signals allowing us to define a 'characteristic seismic response' for soils. In the second experimental campaign, two controlled landslides were experimentally induced by increasing the vertical load on top of a 2m soil scarp. We were able to detect from 1 to 10 centimeter wide crack propagations and displacements, and approximately 20x20x10cm to 100x50x20cm block failure events based on microseismic recordings, field notes, video recordings and displacement measurements of the landslide's crown that failed during the experiments. Direct correlation

  12. The oxidized soot surface: Theoretical study of desorption mechanisms involving oxygenated functionalities and comparison with temperature programed desorption experiments

    NASA Astrophysics Data System (ADS)

    Barco, Gianluca; Maranzana, Andrea; Ghigo, Giovanni; Causà, Mauro; Tonachini, Glauco

    2006-11-01

    The desorption mechanism for oxygenated functionalities on soot is investigated by quantum mechanical calculations on functionalized polycyclic aromatic hydrocarbon (PAH) models and compared with recently published temperature programed desorption-mass spectrometry results. Substituents on PAHs of increasing size (up to 46 carbon atoms in the parent PAH) are chosen to reproduce the local features of an oxidized graphenic soot platelet. Initially, the study is carried out on unimolecular fragmentation (extrusion, in some cases) processes producing HO, CO, or CO2, in model ketones, carboxylic acids, lactones, anhydrides, in one aldehyde, one peroxyacid, one hydroperoxide, one secondary alcohol, and one phenol. Then, a bimolecular process is considered for one of the carboxylic acids. Furthermore, some cooperative effect which can take place by involving two vicinal carboxylic groups (derived from anhydride hydrolysis) is investigated for other four bifunctionalized models. The comparison between the computed fragmentation (desorption) barriers for the assessed mechanisms and the temperature at which maxima occur in TPD spectra (for HO, CO, or CO2 desorption) offers a suggestion for the assignment of these maxima to specific functional groups, i.e., a key to the description of the oxidized surface. Notably, the computations suggest that (1) the desorption mode from a portion of a graphenic platelet functionalized by a carboxylic or lactone groups is significantly dependent from the chemical and geometric local environment. Consequently, we propose that (2) not all carboxylic groups go lost at the relatively low temperatures generally stated, and (3) lactone groups can be identified as producing not only CO2 but also CO.

  13. Comparison of a RELAP5/MOD2 posttest calculation to the data during the recovery portion of a semiscale single-tube steam generator tube rupture experiment

    SciTech Connect

    Chapman, J.C.

    1986-09-01

    This report discusses the comparisons of a RELAP5 posttest calculation of the recovery portion of the Semiscale Mod-2B test S-SG-1 to the test data. The posttest calculation was performed with the RELAP5/MOD2 cycle 36.02 code without updates. The recovery procedure that was calculated mainly consisted of secondary feed and steam using auxiliary feedwater injection and the atmospheric dump valve of the unaffected steam generator (the steam generator without the tube rupture). A second procedure was initiated after the trends of the secondary feed and steam procedure had been established, and this was to stop the safety injection that had been provided by two trains of both the charging and high pressure injection systems. The Semiscale Mod-2B configuration is a small scale (1/1705), nonnuclear, instrumented, model of a Westinghouse four-loop pressurized water reactor power plant. S-SG-1 was a single-tube, cold-side, steam generator tube rupture experiment. The comparison of the posttest calculation and data included comparing the general trends and the driving mechanisms of the responses, the phenomena, and the individual responses of the main parameters.

  14. Comparison of particle-in-cell simulation with experiment for the transport system of the superconducting electron cyclotron resonance ion source VENUS

    SciTech Connect

    Todd, D.S.; Leitner, D.; Leitner, M.; Lyneis, C.M.; Qiang, J.; Grote, D.P.

    2006-03-15

    The three-dimensional, particle-in-cell code WARP has been enhanced to allow end-to-end beam dynamics simulations of the VENUS beam transport system from the extraction region, through a mass-analyzing magnet, and up to a two-axis emittance scanner. This article presents the first results of comparisons between the simulation and experimental data. A helium beam (He{sup +} and He{sup 2+}) is chosen as an initial comparison beam due to its simple mass spectrum. Although a number of simplifications are made for the initial extracted beam, aberration characteristics appear in simulations that are also present in experimental phase-space current-density measurements. Further, measurements of phase-space tilt indicate that simulations must have little or no space-charge neutralization along the transport system to best agree with experiment. In addition, recent measurements of triangular beam structure immediately after the source are presented. This beam structure is related to the source magnetic confinement fields and will need to be taken into account as the initial beam approximations are lifted.

  15. Lava-snow interactions at Tolbachik 2012-13 eruption: comparison to recent field observations and experiments

    NASA Astrophysics Data System (ADS)

    Edwards, B. R.; Belousov, A.; Belousova, M.; Izbekov, P. E.; Bindeman, I. N.; Gardeev, E.; Muravyev, Y. D.; Melnikov, D.

    2013-12-01

    More than a dozen volcanic eruptions in the past twenty years have produced lava interaction with snow or ice, some of which have produced damaging floods/lahars. However, the factors controlling melting during lava-snow/ice interactions is not well understood. Recent observations from the presently ongoing eruption at Tolbachik, Kamchatka confirm some general observations from large-scale experiments, and recent eruptions (2010 Fimmvorduhals; Edwards et al, 2012), but also show new types of behavior not before described. The new observations provide further constraints on heat transfer between ice/snow and three different lava morphologies: ';a'a, pahoehoe, and toothpaste. ';A'a flows at Tolbachik commonly were able to travel over seasonal snow cover (up to 4 m thick), especially where the snow was covered by tephra within 1.5 km of the vent area. Locally, heated meltwater discharge events issued from beneath the front of advancing lava, even though snow observation pits dug in front of advancing ';a'a flows also showed that in some areas melting was not as extensive. Once, an ';a'a flow was seen to collapse through snow, generating short-lived phreatomagmatic/phreatic activity. Closer to the vent, pahoehoe flow lobes and sheet flows occasionally spilled over onto snow and were able to rapidly transit snow with few obvious signs of melting/steam generation. Most of these flows did melt through basal snow layers within 24 hours however. We were also able to closely observe ';toothpaste' lava flows ';intruding' into snow in several locations, including snow-pits, and to watch it pushing up through snow forming temporary snow domes. Toothpaste lava caused the most rapid melting and most significant volumes of steam, as the meltwater drained down into the intruding lava. Behaviour seen at Tolbachik is similar to historic (e.g., Hekla 1947; Einarrson, 1949) and recent observations (e.g. Fimmvorduhals), as well as large-scale experiments (Edwards et al., 2013). While

  16. Liver cirrhosis grading Child-Pugh class B: a Goliath to challenge in laparoscopic liver resection?—prior experience and matched comparisons

    PubMed Central

    Liang, Xiao; Yu, Tunan; Liang, Yuelong; Jing, Renan; Jiang, Wenbing; Li, Jianbo; Ying, Hanning

    2015-01-01

    Background Laparoscopic hepatectomy (LH) is highly difficult in the background of liver cirrhosis. In this case series, we aimed to summarize our prior experience of LH in liver cirrhosis grading Child-Pugh class B. Methods In the LH database of Sir Run Run Shaw Hospital in Zhejiang, China, patients who were pathologically diagnosed with cirrhosis and graded as Child-Pugh class B or C were reviewed. Results Five patients grading Child B were included. There was no Child C case in our LH database. For included cases, median blood loss (BL) was 800 (range, 240-1,000) mL, median operative time was 135 (range, 80-170) minutes, and median length of hospital stay was 9 (range, 7-15) days. Forty percent (2/5) of patients was converted to open. The postoperative complication (PC) rate was 20.0% (1/5). When these Child B cases were compared with Child A cases undergoing LH, there was no statistical significance in BL, complication rate, operative time, open rate and hospital stay (HS) (P>0.05). This finding was confirmed by two ways of matched comparisons (a 1:2 comparison based on age and gender, and a 1:1 propensity score matching). Conclusions Although relevant literatures had suggested feasibility of LH in cirrhotic cases grading Child A, this study was the first one to discuss the value of LH in Child B cases. Our prior experience showed that in selected patients, LH in Child B patients had the potential to be as safe as in Child A cases. The efficacy of LH in Child C patients needs further exploration. PMID:26734623

  17. Large amplitude flutter of a low aspect ratio panel at low supersonic speeds comparison of theory and experiment

    NASA Technical Reports Server (NTRS)

    Ventres, C. S.; Kang, C. K.

    1973-01-01

    Flutter boundaries, as well as flutter limit cycle amplitudes, frequencies and stresses were computed for a panel of length-width ratio 4.48 exposed to applied in-plane and transverse loads. The Mach number range was 1.1 to 1.4. The method used involved direct numerical integration of modal equations of motion derived from the nonlinear plate equations of von Karman, coupled with linearized potential flow aerodynamic theory. The flutter boundaries agreed reasonably well with experiment, except when the in-plane loading approached the buckling load. Structural damping had to be introduced, to produce frequencies comparable to the experimental values. Attempts to compute panel deflections or stress at a given point met with limited success. There is some evidence, however, that deflection and stress maxima can be estimated with somewhat greater accuracy.

  18. O+OH-->O(2)+H: A key reaction for interstellar chemistry. New theoretical results and comparison with experiment.

    PubMed

    Lique, F; Jorfi, M; Honvault, P; Halvick, P; Lin, S Y; Guo, H; Xie, D Q; Dagdigian, P J; Kłos, J; Alexander, M H

    2009-12-14

    We report extensive, fully quantum, time-independent (TID) calculations of cross sections at low collision energies and rate constants at low temperatures for the O+OH reaction, of key importance in the production of molecular oxygen in cold, dark, interstellar clouds and in the chemistry of the Earth's atmosphere. Our calculations are compared with TID calculations within the J-shifting approximation, with wave-packet calculations, and with quasiclassical trajectory calculations. The fully quantum TID calculations yield rate constants higher than those from the more approximate methods and are qualitatively consistent with a low-temperature extrapolation of earlier experimental values but not with the most recent experiments at the lowest temperatures.

  19. Collision-induced rotational excitation in N2 (+)((2)Σg (+),v=0)-Ar: Comparison of computations and experiment.

    PubMed

    Unke, Oliver T; Castro-Palacio, Juan Carlos; Bemish, Raymond J; Meuwly, Markus

    2016-06-14

    The collisional dynamics of N2 (+)((2)Σg (+)) cations with Ar atoms is studied using quasi-classical simulations. N2 (+)-Ar is a proxy to study cooling of molecular ions and interesting in its own right for molecule-to-atom charge transfer reactions. An accurate potential energy surface (PES) is constructed from a reproducing kernel Hilbert space (RKHS) interpolation based on high-level ab initio data. The global PES including the asymptotics is fully treated within the realm of RKHS. From several ten thousand trajectories, the final state distribution of the rotational quantum number of N2 (+) after collision with Ar is determined. Contrary to the interpretation of previous experiments which indicate that up to 98% of collisions are elastic and conserve the quantum state, the present simulations find a considerably larger number of inelastic collisions which supports more recent findings. PMID:27306007

  20. Shock recovery experiments in the range of 10 to 45 GPa - comparison of results of synthetic magnetite and terrestrial diabase

    NASA Astrophysics Data System (ADS)

    Kohout, T.; Pesonen, L.; Deutsch, A.; Honnermann, U.; Heikinheimo, E.

    2008-12-01

    Shock-induced changes in magnetic properties of rocks, minerals and meteorites play an important role in modelling the magnetic anomalies of impact structures (e.g. Vredefort), in interpretation of the magnetic anomalies of planetary bodies (e.g. Mars) and in understanding the paleomagnetic data of meteorites. To shed further light on these problems we report results of experimentally shocked samples of synthetic fine grained magnetite. We used cylindrical surface-polished discs (d 10 mm, h 4 mm) of the well characterized magnetite with SD-PSD grain size range. The magnetite powder was mixed with Al2O3 and sintered into disktype pellets. A series of shock recovery experiments from 10 to 45 GPa (nominal pressure) using a conventional high-explosive set-up with a steel (ARMCO) sample container, surrounded by a momentum trap of the identical material. As the samples were shocked inside the highly magnetic containers, the prevailing magnetic field was roughly five times higher than the ambient field. After the shock, the containers cooled down slowly to ambient temperatures. The estimated post-shock temperatures of the samples range from nearly ambient temperature (10 GPa) up to about 1400 K (45 GPa). Evaluating the "real" pressures reached in these experiments requires a model to account for the high porosity of the pellets. The porosity also affects significantly the post-shock temperature. Independent of the fact that pressure, shock- and post- shock tmperatures are not sufficiently constrained yet, the experiments form a well-characterized series of shocks with systematically increasing pressure. Surprisingly enough, the sample discs were not friable and could be removed by retaining shape largely unchanged. The shock induced changes in sample properties show, with the exception of the 45 GPa sample, with increasing shock pressure: 1. Reduction of bulk density and significant increase in porosity 2. Minor increase in magnetic susceptibility (10 GPa, 15 GPa and 45

  1. Comparison of three labeled silica nanoparticles used as tracers in transport experiments in porous media. Part I: syntheses and characterizations.

    PubMed

    Vitorge, Elsa; Szenknect, Stéphanie; Martins, Jean M F; Barthès, Véronique; Auger, Aurélien; Renard, Oliver; Gaudet, Jean-Paul

    2014-01-01

    The synthesis and the characterization of three kinds of labeled silica nanoparticles were performed. Three different labeling strategies were investigated: fluorescent organic molecule (FITC) embedded in silica matrix, heavy metal core (Ag(0)) and radioactive core ((110m)Ag) surrounded by a silica shell. The main properties and the suitability of each kind of labeled nanoparticle in terms of size, surface properties, stability, detection limits, and cost were determined and compared regarding its use for transport studies. Fluorescent labeling was found the most convenient and the cheapest, but the best detection limits were reached with chemical (Ag(0)) and radio-labeled ((110m)Ag) nanoparticles, which also allowed nondestructive quantifications. This work showed that the choice of labeled nanoparticles as surrogates of natural colloids or manufactured nanoparticles strongly depends on the experimental conditions, especially the concentration and amount required, the composition of the effluent, and the timescale of the experiment.

  2. The MATROSHKA experiment: results and comparison from extravehicular activity (MTR-1) and intravehicular activity (MTR-2A/2B) exposure.

    PubMed

    Berger, Thomas; Bilski, Paweł; Hajek, Michael; Puchalska, Monika; Reitz, Günther

    2013-12-01

    Astronauts working and living in space are exposed to considerably higher doses and different qualities of ionizing radiation than people on Earth. The multilateral MATROSHKA (MTR) experiment, coordinated by the German Aerospace Center, represents the most comprehensive effort to date in radiation protection dosimetry in space using an anthropomorphic upper-torso phantom used for radiotherapy treatment planning. The anthropomorphic upper-torso phantom maps the radiation distribution as a simulated human body installed outside (MTR-1) and inside different compartments (MTR-2A: Pirs; MTR-2B: Zvezda) of the Russian Segment of the International Space Station. Thermoluminescence dosimeters arranged in a 2.54 cm orthogonal grid, at the site of vital organs and on the surface of the phantom allow for visualization of the absorbed dose distribution with superior spatial resolution. These results should help improve the estimation of radiation risks for long-term human space exploration and support benchmarking of radiation transport codes.

  3. A comparison of theory and experiment for coupled rotor-body stability of a hingeless rotor model in hover

    NASA Technical Reports Server (NTRS)

    Bousman, William G.

    1988-01-01

    Three cases were selected for correlation from an experiment that examined the aeromechanical stability of a small-scale model of a hingeless rotor and fuselage in hover. The first case examined the stability of a configuration with 0 degree blade pitch so that coupling between dynamic modes was minimized. The second case was identical to the first except the blade pitch was set to 9 degrees which provides flap-lag coupling of the rotor modes. The third case had 9 degrees of blade pitch and also included negative pitch-lag coupling, and therefore was the most highly coupled configuration. Analytical calculations were made by Bell Helicopter Textron, Boeing Vertol, Hughes Helicopters, Sikorsky Aircraft, the U.S. Army Aeromechanics Laboratory, and NASA Ames Research Center and compared to some or all of the experimental cases. Overall, the correlation ranged from very poor-to-poor to good.

  4. Solvent vapor recovery by pressure swing adsorption. 3: Comparison of simulation with experiment for the butane-activated carbon system

    SciTech Connect

    Liu, J.; Holland, C.E.; Ritter, J.A.

    1999-06-01

    A fully predictive (no adjustable parameters), nonisothermal, multicomponent mathematical model was developed and used to simulate a pressure swing adsorption (PSA) process designed for the separation and recovery of concentrated butane vapor from nitrogen using BAX activated carbon. Nearly quantitative agreement with experiment was realized with this model over a wide range of process conditions, and for both the transient and periodic state process dynamics and the periodic state process performance. The model also verified some unique characteristics of this PSA process, and it revealed some of the subtleties associated with accurately simulating a PSA-solvent vapor recovery (SVR) process. These subtleties included the need to account for the adsorbate heat capacity and the temperature dependence of the gas-phase physical properties. No PSA models in the literature have included both of these features, which were critical to the accurate prediction of the heat effects in this PSA-SVR process.

  5. Comparison of wind tunnel and field experiments to measure potential deposition of fenpropimorph following volatilisation from treated crops.

    PubMed

    Hassink, Jan; Platz, Klaus; Stadler, Reinhold; Zangmeister, Werner; Fent, Gunnar; Möndel, Martin; Kubiak, Roland

    2007-02-01

    The potential for short-range transport via air, i.e. volatilisation from the area of application and subsequent deposition on adjacent non-target areas, was investigated for the fungicide fenpropimorph in a wind tunnel system and under outdoor conditions in a higher-tier field study. Fenpropimorph 750 g L(-1) EC was applied post-emergence to cereal along with a reference standard lindane EC. Stainless steel containers of water were placed at different distances downwind of the application area to trap volatile residues during a study period of 24 h following application. Meteorological conditions in the wind tunnel as well as on the field were constantly monitored during the study period. The wind tunnel system was a partly standardised system on a semi-field scale, i.e. wind direction and wind speed (2 m s(-1)) were constant, but temperature and humidity varied according to the conditions outside. In the field experiment, the average wind speed over the 24 h study period was 3 m s(-1) and no rainfall occurred. Three different measuring lines were installed on the non-target area beside the treated field to cover potential variations in the wind direction. However, no significant differences were observed since the wind direction was generally constant. Fenpropimorph was detected in minor amounts of 0.01-0.05% of the applied material in the wind tunnel experiment. Even at a distance of 1 m beside the treated field, no significant deposition occurred (0.04% of applied material after 24 h). In the field, less than 0.1% of the applied fenpropimorph was detected at 0 m directly beside the treated field. At 5 m distance the deposition values were below 0.04%, and at 20 m distance about 0.01%. In general, the amounts of deposited fenpropimorph detected in the partly standardised wind tunnel system and the higher-tier field study were in good agreement.

  6. Two-dimensional model of a capacitively coupled rf discharge and comparisons with experiments in the Gaseous Electronics Conference reference reactor

    NASA Astrophysics Data System (ADS)

    Boeuf, J. P.; Pitchford, L. C.

    1995-02-01

    We present results from a two-dimensional (2D) numerical fluid model of rf discharges in conditions close to recently published measurements of the spatial distribution of plasma density in the Gaseous Electronic Conference reference cell. The discharge is in pure argon at pressures in the 100 mtorr range, frequency 13.56 MHz, and rf voltage amplitudes on the order of 100 V. The model is based on solutions of the continuity, momentum (drift-diffusion), and energy equations for the electrons, continuity, and drift-diffusion equation for positive ions, coupled with the Poisson equation. The results of the model are qualitatively and quantitatively in good agreement with the experiments. The model predicts a maximum of plasma density off axis, as in the experiment. The ion current density on the electrode is also nonuniform, and increases radially in the conditions of the experiments. The effects of the rf voltage, pressure, and reactor geometry (electrode dimensions, gap length, guard rings, etc.) on the plasma properties and on the uniformity of the ion current on the powered electrode are also discussed. It is shown that the existence of a maximum of plasma density in the radial direction, in the conditions of the experiment, is due to the small value of the electrode spacing. The results show that the harmonic content of the discharge current is also geometry dependent. The comparisons show that 2D, three-moment fluid models can accurately describe the discharge and the effects of the chamber geometry on the plasma properties for pressure above the limit where collisionless electron heating does not play a significant role.

  7. Comparison of aromatic hydrocarbon measurements made by PTR-MS, DOAS and GC-FID during the MCMA 2003 Field Experiment

    NASA Astrophysics Data System (ADS)

    Jobson, B. T.; Volkamer, R. A.; Velasco, E.; Allwine, G.; Westberg, H.; Lamb, B. K.; Alexander, M. L.; Berkowitz, C. M.; Molina, L. T.

    2010-02-01

    A comparison of aromatic hydrocarbon measurements is reported for the CENICA supersite in the district of Iztapalapa during the Mexico City Metropolitan Area field experiment in April 2003 (MCMA 2003). Data from three different measurement methods were compared: a Proton Transfer Reaction Mass Spectrometer (PTR-MS), long path measurements using a UV Differential Optical Absorption Spectrometer (DOAS), and Gas Chromatography-Flame Ionization analysis (GC-FID) of canister samples. The principle focus was on the comparison between PTR-MS and DOAS data. Lab tests established that the PTR-MS and DOAS calibrations were consistent for a suite of aromatic compounds including benzene, toluene, p-xylene, ethylbenzene, 1,2,4-trimethylbenzene, phenol and styrene. The point sampling measurements by the PTR-MS and GC-FID showed good correlations (r=0.6), and were in reasonable agreement for toluene, C2-alkylbenzenes and C3-alkylbenzenes. The PTR-MS benzene data were consistently high, indicating interference from ethylbenzene fragmentation for the 145 Td drift field intensity used in the experiment. Correlations between the open-path data measured at 16-m height over a 860-m path length (retroreflector in 430 m distance), and the point measurements collected at 37-m sampling height were best for benzene (r=0.61), and reasonably good for toluene, C2-alkylbenzenes, naphthalene, styrene, cresols and phenol (r>0.5). There was good agreement between DOAS and PTR-MS measurements of benzene after correction for the PTR-MS ethylbenzene interference. Mixing ratios measured by DOAS were on average a factor of 1.7 times greater than the PTR-MS data for toluene, C2-alkylbenzenes, naphthalene and styrene. The level of agreement for the toluene data displayed a modest dependence on wind direction, establishing that spatial gradients - horizontal, vertical, or both - in toluene mixing ratios were significant, and up to a factor of 2 despite the fact that all measurements were conducted above

  8. Comparison of Aromatic Hydrocarbon Measurements made by PTR-MS, DOAS and GC-FID during the MCMA 2003 Field Experiment

    SciTech Connect

    Jobson, Bertram T.; Volkamer, Rainer M.; Velasco, E.; Allwine, Gene; Westberg, Halvor H.; Lamb, Brian K.; Alexander, M. L.; Berkowitz, Carl M.; Molina, Luisa T.

    2010-02-15

    A comparison of aromatic hydrocarbon measurements is reported for the CENICA upersite in the district of Iztapalapa during the Mexico City Metropolitan Area field experiment in April 2003 (MCMA 2003). Data from three different measurement methods were compared: a Proton Transfer Reaction Mass Spectrometer (PTR-MS), long path measurements using a UV Differential Optical Absorption Spectrometer (DOAS), and Gas Chromatography-Flame Ionization analysis (GC-FID) of canister samples. The principle focus was on the comparison between PTR-MS and DOAS data. Lab tests established that the PTR-MS and DOAS calibrations were consistent for a suite of aromatic compounds including benzene, toluene, p-xylene, ethylbenzene, 1,2,4-trimethylbenzene, phenol and styrene. The point sampling measurements by the PTR-MS and GC-FID showed good correlations (r=0.6), and were in reasonable agreement for toluene, C₂-alkylbenzenes and C3-alkylbenzenes. The PTR-MS benzene data were consistently high, indicating interference from ethylbenzene fragmentation for the 145 Td drift field intensity used in the experiment. Correlations between the open-path data measured at 16-m height over a 860-m path length (retroreflector in 430m distance), and the point measurements collected at 37-m sampling height were best for benzene (r=0.61), and reasonably good for toluene, C2-alkylbenzenes, naphthalene, styrene, cresols and phenol (r>0.5). There was good agreement between DOAS and PTR-MS measurements of benzene after correction for the PTR-MS ethylbenzene interference. Mixing ratios easured by DOAS were on average a factor of 1.7 times greater than the PTR-MS data for toluene, C2-alkylbenzenes, naphthalene and styrene. The level of agreement for the toluene data displayed a modest dependence on wind direction, establishing that spatial gradients - horizontal, vertical, or both – in toluene mixing ratios were significant, and up to a factor of 2 despite the fact that all measurements were conducted above

  9. Two-domain description of solute transport in heterogeneous porous media: Comparison between theoretical predictions and numerical experiments

    NASA Astrophysics Data System (ADS)

    Cherblanc, F.; Ahmadi, A.; Quintard, M.

    2007-05-01

    This paper deals with two-equation models describing solute transport in highly heterogeneous porous systems and more particularly dual permeability structures composed of high- and low-permeability regions. A macroscopic two-equation model has been previously proposed in the literature based on the volume averaging technique [Ahmadi A, Quintard M, Whitaker S. Transport in chemically and mechanically heterogeneous porous media V: two-equation model for solute transport with adsorption, Adv Water Resour 1998;22:59-86; Cherblanc F, Ahmadi A, Quintard M. Two-medium description of dispersion in heterogeneous porous media: calculation of macroscopic properties. Water Resour Res 2003;39(6):1154-73]. Through this theoretical upscaling method, both convection and dispersion mechanisms are taken into account in both regions, allowing one to deal with a large range of heterogeneous systems. In this paper, the numerical tools associated with this model are developed in order to test the theory by comparing macroscopic concentration fields to those obtained by Darcy-scale numerical experiments. The heterogeneous structures considered are made up of low-permeability nodules embedded in a continuous high-permeability region. Several permeability ratios are used, leading to very different macroscopic behaviours. Taking advantage of the Darcy-scale simulations, the role of convection and dispersion in the mass exchange between the two regions is investigated. Large-scale averaged concentration fields and elution curves are extracted from the Darcy-scale numerical experiments and compared to the theoretical predictions given by the two-equation model. Very good agreement is found between experimental and theoretical results. A permeability ratio around 100 presents a behaviour characteristic of "mobile-mobile" systems emphasizing the relevance of this two-equation description. Eventually, the theory is used to set-up a criterion for the existence of local equilibrium conditions

  10. Low-speed impact simulations into regolith in support of asteroid sampling mechanism design I: Comparison with 1-g experiments

    NASA Astrophysics Data System (ADS)

    Schwartz, Stephen R.; Michel, Patrick; Richardson, Derek C.; Yano, Hajime

    2014-11-01

    This study is carried out in the framework of sample-return missions to asteroids that use a low-speed projectile as the primary component of its sampling mechanism (e.g., JAXA's Hayabusa and Hayabusa2 missions). We perform numerical simulations of such impacts into granular materials using different projectile shapes under Earth's gravity. We then compare the amounts of ejected mass obtained in our simulations against what was found in experiments that used similar setups, which allows us to validate our numerical approach. We then investigate the sensitivity of various parameters involved in the contacts between grains on the amount of mass that is ejected. For the targets, we consider 2 different monodisperse grain-diameter sizes: 5 mm and 3 mm. The impact speed of the projectile is 11 m s-1, and is directed downward, perpendicular to the surface of the targets. Using an implementation of the soft-sphere discrete element method (SSDEM) in the N-body gravity tree code pkdgrav, previously validated in the context of low-speed impacts into sintered glass bead agglomerates, we find a noticeable dependence of the amount of ejected mass on the projectile shape. As found in experiments, in the case of the larger target grain size (5 mm), a conically shaped projectile ejects a greater amount of mass than do projectiles of other shapes, including disks and spheres. We then find that numerically the results are sensitive to the normal coefficient of restitution of the grains, especially for impacts into targets comprising smaller grains (3 mm). We also find that static friction plays a more important role for impacts into targets comprising the larger grains. As a preliminary demonstration, one of these considered setups is simulated in a microgravity environment. As expected, a reduction in gravity increases both the amount of ejected mass and the timescale of the impact process. A dedicated quantitative study in microgravity is the subject of future work. We also plan

  11. Statics and dynamics of halide sub-monolayer electrosorption on silver: Computer simulations with comparison to experiments

    NASA Astrophysics Data System (ADS)

    Abou Hamad, Ibrahim

    This dissertation investigates equilibrium and dynamical properties of sub-monolayer chemical adsorption of Br and Cl on single-crystal Ag(100) electrodes. Computational methods, such as Monte Carlo simulations with First-order Reversal Curve analysis, are used along with experimental data in this study. Monte Carlo simulations of a two-dimensional lattice-gas approximation for the adlayer are used to explore equilibrium properties of the system. Lateral interaction energies between adsorbates, as well other system parameters like the electrosorption valency, are determined by fitting simulations to experimental chronocoulometry isotherms. While neither the electrosorption valency nor the lateral interactions show any dependence on the adsorbate coverage for the Br/Ag(100) system, a model in which both are coverage dependent is required to adequately describe the Cl/Ag(100) system. A self-consistent, entirely electrostatic picture of the lateral interactions with coverage dependence is developed, and a relationship between the lateral interactions and the electrosorption valency is investigated for Cl on Ag(100). The adsorbates form a disordered adlayer at low electrochemical potentials. At a more positive elctrochemical potential the adlayer undergoes a disorder-order phase transition at to an ordered c(2 x 2) phase. This phase transition produces a peak in the current density observed in cyclic-voltammetry experiments. Kinetic Monte Carlo of the lattice-gas model are used to simulate cyclic-voltammetry experiments. The scan-rate dependence of the separation between positive- and negative-going peaks in cyclic voltammetry simulations are compared to experimental peak separations. This dynamics study identifies the inverse Monte Carlo attempt frequency with a physical timescale. Although kinetic Monte Carlo simulations can provide long-time simulations of the dynamics of physical and chemical systems, this identification is not yet possible in general. To further

  12. Comparison of two types of municipal solid waste incinerator fly ashes with different alkaline reagents in washing experiments.

    PubMed

    Zhu, Fenfen; Takaoka, Masaki; Oshita, Kazuyuki; Takeda, Nobuo

    2009-01-01

    In this study, we propose a "washing-calcination-conversion of washed fly ash into cement material with bottom ash" (WCCB) system to reduce the amount of fly ash that must be specially treated so it can be used as raw cement material. Calcium hydroxide (Ca(OH)2) is widely used in air-pollution control devices of incinerators while sodium bicarbonate (NaHCO3) is not. We conducted single-, double-, and triple-washing experiments to compare the washing characteristics of two types of fly ash. Unlike NaHCO3 fly ash, Ca(OH)2 fly ash has almost twice as much washed residue and almost 2.5 times more chlorine after the same washing procedure. After washing once, the washing frequency is also important for NaHCO3 fly ash, while the mixing time and liquid/solid ratio are more critical for Ca(OH)2 fly ash. The use of NaHCO3 is more suitable for the WCCB system. PMID:18539449

  13. Reduced model simulations of the scrape-off-layer heat-flux width and comparison with experiment

    SciTech Connect

    Myra, J. R.; Russell, D. A.; D’Ippolito, D. A.; Ahn, J.-W.; Maingi, R.; Maqueda, R. J.; Lundberg, D. P.; Stotler, D. P.; Zweben, S. J.; Boedo, J.; Umansky, M.

    2011-01-01

    Reduced model simulations of turbulence in the edge and scrape-off-layer (SOL) region of a spherical torus or tokamak plasma are employed to address the physics of the scrape-off-layer heat flux width. The simulation model is an electrostatic two-dimensional fluid turbulence model, applied in the plane perpendicular to the magnetic field at the outboard midplane of the torus. The model contains curvature-driven-interchange modes, sheath losses, and both perpendicular turbulent diffusive and convective (blob) transport. These transport processes compete with classical parallel transport to set the SOL width. Midplane SOL profiles of density, temperature and parallel heat flux are obtained from the simulation and compared with experimental results from the National Spherical Torus Experiment (NSTX) to study the scaling of the heat flux width with power and plasma current. It is concluded that midplane turbulence is the main contributor to the SOL heat flux width for the low power H-mode discharges studied, while additional physics is required to explain the plasma current scaling of the SOL heat flux width observed experimentally in higher power discharges. Intermittent separatrix spanning convective cells are found to be the main mechanism that sets the near-SOL width in the simulations. The roles of sheared flows and blob trapping vs. emission are discussed.

  14. Comparison of experiment and models of geodesic acoustic mode frequency and amplitude geometric scaling in ASDEX Upgrade

    NASA Astrophysics Data System (ADS)

    Simon, P.; Conway, G. D.; Stroth, U.; Biancalani, A.; Palermo, F.; the ASDEX Upgrade Team

    2016-04-01

    In a set of dedicated ASDEX Upgrade shape-scan experiments, the influence of plasma geometry on the frequency and amplitude behaviour of the geodesic acoustic mode (GAM), measured by Doppler reflectometry, is studied. In both limiter and divertor configurations, the plasma elongation was varied between circular and highly elongated states (1.1<κ <1.8 ). Also, the edge safety factor was scanned between 3  <  q  <  5. The GAM frequency {ω\\text{GAM}} and amplitude are used to test several models (heuristic, fluid and gyrokinetic based), which incorporate various plasma geometry effects. The experimentally observed effect of decreasing {ω\\text{GAM}} with increasing κ is predicted by most models. Other geometric factors, such as inverse aspect ratio ε and Shafranov shift gradient {Δ\\prime} are also seen to be influential in determining a reliable lower {ω\\text{GAM}} boundary. The GAM amplitude is found to vary with boundary elongation {κ\\text{b}} and safety factor q. The collisional damping is compared to multiple models for the collisionless damping. Collisional damping appears to play a stronger role in the divertor configuration, while collisional and collisionless damping both may contribute to the GAM amplitude in the limiter configuration.

  15. Two fluid effects on three-dimensional reconnection in the Swarthmore Spheromak Experiment with comparisons to space data

    SciTech Connect

    Brown, M.R.; Cothran, C.D.; Fung, J.

    2006-05-15

    Several new experimental results are reported from spheromak merging studies at the Swarthmore Spheromak Experiment [M. R. Brown, Phys. Plasmas 6, 1717 (1999)] with relevance to three-dimensional (3D) reconnection in laboratory and space plasmas. First, recent velocity measurements of impurity ions using ion Doppler spectroscopy are reported. Bidirectional outflow at nearly the Alfven speed is clearly observed. Second, experimental measurements of the out-of-plane magnetic field in a reconnection volume showing a quadrupolar structure at the ion inertial scale are discussed. Third, a measurement of in-plane Hall electric field and nonideal terms of the generalized Ohm's law in a reconnection volume of a weakly collisional laboratory plasma is presented. Time resolved vector magnetic field measurements on a 3D lattice [B(r,t)] enables evaluation of the various terms. Results show that the Hall electric field dominates everywhere (JxB/ne) and also exhibits a quadrupolar structure at the ion inertial scale; resistive and electron inertia terms are small. Each of these is related to and compared with similar measurements in a solar or space context.

  16. The initial magnetic susceptibility of polydisperse ferrofluids: A comparison between experiment and theory over a wide range of concentration

    NASA Astrophysics Data System (ADS)

    Solovyova, Anna Y.; Goldina, Olga A.; Ivanov, Alexey O.; Lebedev, Aleksandr V.; Elfimova, Ekaterina A.

    2016-08-01

    Temperature dependencies of the static initial magnetic susceptibility for ferrofluids at various concentrations are studied using experiment and statistical-mechanical theories. Magnetic susceptibility measurements are carried out for twelve samples of magnetite-based fluids stabilized with oleic acid over a wide range of temperatures (210 K ≲T ≲ 390 K); all samples have the same granulometric composition but different volume ferroparticle concentrations (0.2 ≲ φ ≲ 0.5). Experimental results are analyzed using three theories: the second-order modified mean-field theory (MMF2) [A. O. Ivanov and O. B. Kuznetsova, Phys. Rev. E 64, 41405 (2001)]; its correction for polydisperse ferrofluids arising from Mayer-type cluster expansion and taking into account the first terms of the polydisperse second virial coefficient [A. O. Ivanov and E. A. Elfimova, J. Magn. Magn. Mater 374, 327 (2015)]; and a new theory based on MMF2 combined with the first terms of the polydisperse second and third virial contributions to susceptibility. It turns out that the applicability of each theory depends on the experimental sample density. If twelve ferrofluid samples are split into three groups of strong, moderate, and low concentrated fluids, the temperature dependences of the initial magnetic susceptibility in each group are very precisely described by one of the three theories mentioned above. The determination of a universal formula predicting a ferrofluid susceptibility over a broad range of concentrations and temperatures remains as a challenge.

  17. Ionization of small molecules induced by H+, H e+ , and N+ projectiles: Comparison of experiment with quantum and classical calculations

    NASA Astrophysics Data System (ADS)

    Kovács, S. T. S.; Herczku, P.; Juhász, Z.; Sarkadi, L.; Gulyás, L.; Sulik, B.

    2016-07-01

    We report the energy and angular distribution of ejected electrons from C H4 and H2O molecules impacted by 1 MeV H+, H e+ , and 650 keV N+ ions. Spectra were measured at different observation angles, from 2 to 2000 eV. The obtained absolute double-differential electron-emission cross sections (DDCSs) were compared with the results of classical trajectory Monte Carlo (CTMC) and continuum distorted wave, eikonal initial state (CDW-EIS) calculations. For the bare H+ projectile both theories show remarkable agreement with the experiment at all observed angles and energies. The CTMC results are in similarly good agreement with the DDCS spectra obtained for impact by dressed H e+ and N+ ions, where screening effects and electron loss from the projectile gain importance. The CDW-EIS calculations slightly overestimate the electron loss for 1 MeV H e+ impact, and overestimate both the target and projectile ionization at low emitted electron energies for 650 keV N+ impact. The contribution of multiple electron scattering by the projectile and target centers (Fermi shuttle) dominates the N+-impact spectra at higher electron energies, and it is well reproduced by the nonperturbative CTMC calculations. The contributions of different processes in medium-velocity collisions of dressed ions with molecules are determined.

  18. Insight into acid-base nucleation experiments by comparison of the chemical composition of positive, negative, and neutral clusters.

    PubMed

    Bianchi, Federico; Praplan, Arnaud P; Sarnela, Nina; Dommen, Josef; Kürten, Andreas; Ortega, Ismael K; Schobesberger, Siegfried; Junninen, Heikki; Simon, Mario; Tröstl, Jasmin; Jokinen, Tuija; Sipilä, Mikko; Adamov, Alexey; Amorim, Antonio; Almeida, Joao; Breitenlechner, Martin; Duplissy, Jonathan; Ehrhart, Sebastian; Flagan, Richard C; Franchin, Alessandro; Hakala, Jani; Hansel, Armin; Heinritzi, Martin; Kangasluoma, Juha; Keskinen, Helmi; Kim, Jaeseok; Kirkby, Jasper; Laaksonen, Ari; Lawler, Michael J; Lehtipalo, Katrianne; Leiminger, Markus; Makhmutov, Vladimir; Mathot, Serge; Onnela, Antti; Petäjä, Tuukka; Riccobono, Francesco; Rissanen, Matti P; Rondo, Linda; Tomé, António; Virtanen, Annele; Viisanen, Yrjö; Williamson, Christina; Wimmer, Daniela; Winkler, Paul M; Ye, Penglin; Curtius, Joachim; Kulmala, Markku; Worsnop, Douglas R; Donahue, Neil M; Baltensperger, Urs

    2014-12-01

    We investigated the nucleation of sulfuric acid together with two bases (ammonia and dimethylamine), at the CLOUD chamber at CERN. The chemical composition of positive, negative, and neutral clusters was studied using three Atmospheric Pressure interface-Time Of Flight (APi-TOF) mass spectrometers: two were operated in positive and negative mode to detect the chamber ions, while the third was equipped with a nitrate ion chemical ionization source allowing detection of neutral clusters. Taking into account the possible fragmentation that can happen during the charging of the ions or within the first stage of the mass spectrometer, the cluster formation proceeded via essentially one-to-one acid-base addition for all of the clusters, independent of the type of the base. For the positive clusters, the charge is carried by one excess protonated base, while for the negative clusters it is carried by a deprotonated acid; the same is true for the neutral clusters after these have been ionized. During the experiments involving sulfuric acid and dimethylamine, it was possible to study the appearance time for all the clusters (positive, negative, and neutral). It appeared that, after the formation of the clusters containing three molecules of sulfuric acid, the clusters grow at a similar speed, independent of their charge. The growth rate is then probably limited by the arrival rate of sulfuric acid or cluster-cluster collision.

  19. Comparison of horizontal dust fluxes simulated with two dust emission schemes based on field experiments in Xinjiang, China

    NASA Astrophysics Data System (ADS)

    Yang, Xinghua; Yang, Fan; Liu, Xinchun; Huo, Wen; He, Qing; Mamtimin, Ali; Zhang, Qingyu

    2016-10-01

    Horizontal dust fluxes were simulated with two different dust emission schemes developed by Marticorena and Shao (hereinafter referred to as the M scheme, S scheme, and S scheme corrections), based on field experiments over a bare desert surface and a vegetated desert surface from May 19 to June 18, 2010 in Xinjiang, China. The M scheme produced a much higher dust emission than the S schemes over different surface conditions, with the emission being about 4 times larger than that produced by the S schemes over the bare desert, and 3 to 200 times larger over the vegetated surface. Compared to observations, the missing report rate of wind erosion events was about 30 % for the S schemes and about 10 % for the M scheme over the bare desert surface, while all schemes had a false alarm rate of wind erosion events over the vegetated desert surface. The total dust emission from the bare desert surface during the study period was 674.4, 551.5, 595.2, and 2995.8 kg/m for observation, the S scheme, S scheme correction 2, and M scheme, respectively. Total dust emission from the vegetated desert surface was 1.6, 0, 55.5, 0.9, and 227.7 kg/m for observation, the S scheme, S scheme correction 1, S scheme correction 2, and M scheme, respectively.

  20. Spectrometric analyses in comparison to the physiological condition of heavy metal stressed floodplain vegetation in a standardised experiment

    NASA Astrophysics Data System (ADS)

    Götze, Christian; Jung, András; Merbach, Ines; Wennrich, Rainer; Gläßer, Cornelia

    2010-06-01

    Floodplain ecosystems are affected by flood dynamics, nutrient supply as well as anthropogenic activities. Heavy metal pollution poses a serious environmental challenge. Pollution transfer from the soil to vegetation is still present at the central location of Elbe River, Germany. The goal of this study was to assess and separate the current heavy metal contamination of the floodplain ecosystem, using spectrometric field and laboratory measurements. A standardized pot experiment with floodplain vegetation in differently contaminated soils provided the basis for the measurements. The dominant plant types of the floodplains are: Urtica dioica, Phalaris arundinacea and Alopecurus pratensis, these were also chemically analysed. Various vegetation indices and methods were used to estimate the red edge position, to normalise the spectral curve of the vegetation and to investigate the potential of different methods for separating plant stress in floodplain vegetation. The main task was to compare spectral bands during phenological phases to find a method to detect heavy metal stress in plants. A multi-level algorithm for the curve parameterisation was developed. Chemo-analytical and ecophysiological parameters of plants were considered in the results and correlated with spectral data. The results of this study show the influence of heavy metals on the spectral characteristics of the focal plants. The developed method (depth CR1730) showed significant relationship between the plants and the contamination.

  1. The initial magnetic susceptibility of polydisperse ferrofluids: A comparison between experiment and theory over a wide range of concentration.

    PubMed

    Solovyova, Anna Y; Goldina, Olga A; Ivanov, Alexey O; Lebedev, Aleksandr V; Elfimova, Ekaterina A

    2016-08-28

    Temperature dependencies of the static initial magnetic susceptibility for ferrofluids at various concentrations are studied using experiment and statistical-mechanical theories. Magnetic susceptibility measurements are carried out for twelve samples of magnetite-based fluids stabilized with oleic acid over a wide range of temperatures (210 K ≲T ≲ 390 K); all samples have the same granulometric composition but different volume ferroparticle concentrations (0.2 ≲ φ ≲ 0.5). Experimental results are analyzed using three theories: the second-order modified mean-field theory (MMF2) [A. O. Ivanov and O. B. Kuznetsova, Phys. Rev. E 64, 41405 (2001)]; its correction for polydisperse ferrofluids arising from Mayer-type cluster expansion and taking into account the first terms of the polydisperse second virial coefficient [A. O. Ivanov and E. A. Elfimova, J. Magn. Magn. Mater 374, 327 (2015)]; and a new theory based on MMF2 combined with the first terms of the polydisperse second and third virial contributions to susceptibility. It turns out that the applicability of each theory depends on the experimental sample density. If twelve ferrofluid samples are split into three groups of strong, moderate, and low concentrated fluids, the temperature dependences of the initial magnetic susceptibility in each group are very precisely described by one of the three theories mentioned above. The determination of a universal formula predicting a ferrofluid susceptibility over a broad range of concentrations and temperatures remains as a challenge. PMID:27586948

  2. ELMs and constraints on the H-mode pedestal: peeling ballooning stability calculation and comparison with experiment

    NASA Astrophysics Data System (ADS)

    Snyder, P. B.; Wilson, H. R.; Ferron, J. R.; Lao, L. L.; Leonard, A. W.; Mossessian, D.; Murakami, M.; Osborne, T. H.; Turnbull, A. D.; Xu, X. Q.

    2004-02-01

    We review and test the peeling-ballooning model for edge localized modes (ELMs) and pedestal constraints, a model based upon theoretical analysis of magnetohydrodynamic (MHD) instabilities that can limit the pedestal height and drive ELMs. A highly efficient MHD stability code, ELITE, is used to calculate quantitative stability constraints on the pedestal, including constraints on the pedestal height. Because of the impact of collisionality on the bootstrap current, these pedestal constraints are dependent on the density and temperature separately, rather than simply on the pressure. ELITE stability calculations are directly compared with experimental data for a series of plasmas in which the density is varied and ELM characteristics change. In addition, a technique is developed whereby peeling-ballooning pedestal constraints are calculated as a function of key equilibrium parameters via ELITE calculations using series of model equilibria. This technique is used to successfully compare the expected pedestal height as a function of density, triangularity and plasma current with experimental data. Furthermore, the technique can be applied for parameter ranges beyond the purview of present experiments, and we present a brief projection of peeling-ballooning pedestal constraints for burning plasma tokamak designs.

  3. A comparison of vertical velocity in cirrus obtained from aircraft and lidar divergence measurements during FIRE. [First ISCCP Regional Experiment

    NASA Technical Reports Server (NTRS)

    Gultepe, Ismail; Heymsfield, A. J.; Lenschow, D. H.

    1990-01-01

    Techniques are presented to obtain vertical velocity in cirrus clouds from in situ aircraft lateral wind measurements and from ground-based remote Doppler lidar measurements. The approach used is to calculate w from the integral of the divergence of the horizontal velocity around a closed path. Divergence measurements from both aircraft and Doppler lidar are discussed. The principal errors in the calculation of w from aircraft lateral wind measurements are bias in the lateral wind, ground speed errors, and error due to vertical shear of the horizontal wind. For Doppler lidar measurements the principal errors are in the estimate of mean terminal velocity and the zeroth order coefficients of the Fourier series that is fitted to the data. The technique is applied to a cirrus cloud investigated during the FIRE (First International Satellite Cloud Climatology Regional Experiment) Cirrus Intensive Field Observation Program. The results indicate that the error in w is about + or - 14 cm/s from the aircraft technique; this can be reduced to about + or - 2 to 3 cm/s with technical improvements in both ground speed and lateral velocity measurements. The error in w from Doppler lidar measurements, which is about + or - 8 cm/s, can be reduced to about + or - 5 cm/s by improvements in the Doppler velocity measurements with technology that is currently available.

  4. Insight into acid-base nucleation experiments by comparison of the chemical composition of positive, negative, and neutral clusters.

    PubMed

    Bianchi, Federico; Praplan, Arnaud P; Sarnela, Nina; Dommen, Josef; Kürten, Andreas; Ortega, Ismael K; Schobesberger, Siegfried; Junninen, Heikki; Simon, Mario; Tröstl, Jasmin; Jokinen, Tuija; Sipilä, Mikko; Adamov, Alexey; Amorim, Antonio; Almeida, Joao; Breitenlechner, Martin; Duplissy, Jonathan; Ehrhart, Sebastian; Flagan, Richard C; Franchin, Alessandro; Hakala, Jani; Hansel, Armin; Heinritzi, Martin; Kangasluoma, Juha; Keskinen, Helmi; Kim, Jaeseok; Kirkby, Jasper; Laaksonen, Ari; Lawler, Michael J; Lehtipalo, Katrianne; Leiminger, Markus; Makhmutov, Vladimir; Mathot, Serge; Onnela, Antti; Petäjä, Tuukka; Riccobono, Francesco; Rissanen, Matti P; Rondo, Linda; Tomé, António; Virtanen, Annele; Viisanen, Yrjö; Williamson, Christina; Wimmer, Daniela; Winkler, Paul M; Ye, Penglin; Curtius, Joachim; Kulmala, Markku; Worsnop, Douglas R; Donahue, Neil M; Baltensperger, Urs

    2014-12-01

    We investigated the nucleation of sulfuric acid together with two bases (ammonia and dimethylamine), at the CLOUD chamber at CERN. The chemical composition of positive, negative, and neutral clusters was studied using three Atmospheric Pressure interface-Time Of Flight (APi-TOF) mass spectrometers: two were operated in positive and negative mode to detect the chamber ions, while the third was equipped with a nitrate ion chemical ionization source allowing detection of neutral clusters. Taking into account the possible fragmentation that can happen during the charging of the ions or within the first stage of the mass spectrometer, the cluster formation proceeded via essentially one-to-one acid-base addition for all of the clusters, independent of the type of the base. For the positive clusters, the charge is carried by one excess protonated base, while for the negative clusters it is carried by a deprotonated acid; the same is true for the neutral clusters after these have been ionized. During the experiments involving sulfuric acid and dimethylamine, it was possible to study the appearance time for all the clusters (positive, negative, and neutral). It appeared that, after the formation of the clusters containing three molecules of sulfuric acid, the clusters grow at a similar speed, independent of their charge. The growth rate is then probably limited by the arrival rate of sulfuric acid or cluster-cluster collision. PMID:25406110

  5. Comparison of beam emission spectroscopy and gas puff imaging edge fluctuation measurements in National Spherical Torus Experiment

    SciTech Connect

    Sechrest, Y.; Munsat, T.; Smith, D.; Stotler, D. P.; Zweben, S. J.

    2015-05-15

    In this study, the close physical proximity of the Gas Puff Imaging (GPI) and Beam Emission Spectroscopy (BES) diagnostics on the National Spherical torus Experiment (NSTX) is leveraged to directly compare fluctuation measurements, and to study the local effects of the GPI neutral deuterium puff during H-mode plasmas without large Edge Localized Modes. The GPI and BES views on NSTX provide partially overlapping coverage of the edge and scrape-off layer (SOL) regions above the outboard midplane. The separation in the toroidal direction is 16°, and field lines passing through diagnostic views are separated by ∼20 cm in the direction perpendicular to the magnetic field. Strong cross-correlation is observed, and strong cross-coherence is seen for frequencies between 5 and 15 kHz. Also, probability distribution functions of fluctuations measured ∼3 cm inside the separatrix exhibit only minor deviations from a normal distribution for both diagnostics, and good agreement between correlation length estimates, decorrelation times, and structure velocities is found at the ±40% level. While the two instruments agree closely in many respects, some discrepancies are observed. Most notably, GPI normalized fluctuation levels exceed BES fluctuations by a factor of ∼9. BES mean intensity is found to be sensitive to the GPI neutral gas puff, and BES normalized fluctuation levels for frequencies between 1 and 10 kHz are observed to increase during the GPI puff.

  6. Reduced model simulations of the scrape-off-layer heat-flux width and comparison with experiment

    DOE PAGES

    Myra, J. R.; Russell, D. A.; D’Ippolito, D. A.; Ahn, J.-W.; Maingi, R.; Maqueda, R. J.; Lundberg, D. P.; Stotler, D. P.; Zweben, S. J.; Boedo, J.; et al

    2011-01-01

    Reduced model simulations of turbulence in the edge and scrape-off-layer (SOL) region of a spherical torus or tokamak plasma are employed to address the physics of the scrape-off-layer heat flux width. The simulation model is an electrostatic two-dimensional fluid turbulence model, applied in the plane perpendicular to the magnetic field at the outboard midplane of the torus. The model contains curvature-driven-interchange modes, sheath losses, and both perpendicular turbulent diffusive and convective (blob) transport. These transport processes compete with classical parallel transport to set the SOL width. Midplane SOL profiles of density, temperature and parallel heat flux are obtained from themore » simulation and compared with experimental results from the National Spherical Torus Experiment (NSTX) to study the scaling of the heat flux width with power and plasma current. It is concluded that midplane turbulence is the main contributor to the SOL heat flux width for the low power H-mode discharges studied, while additional physics is required to explain the plasma current scaling of the SOL heat flux width observed experimentally in higher power discharges. Intermittent separatrix spanning convective cells are found to be the main mechanism that sets the near-SOL width in the simulations. The roles of sheared flows and blob trapping vs. emission are discussed.« less

  7. Analysis of Radiation from Implosions of Stainless Steel Wire Arrays on Zebra and Comparison with Laser Plasma Experiments on Leopard at UNR*.

    NASA Astrophysics Data System (ADS)

    Safronova, A. S.; Kantsyrev, V. L.; Shrestha, I.; Shlyaptseva, V. V.; Weller, M. E.; Osborne, G. C.; Williamson, K. M.; Stafford, A.; Keim, S. F.; Faenov, A. Ya.; Esaulov, A. A.; Wiewior, P.; Legalloudec, N.; Paudel, Y.; Coverdale, C. A.; Chuvatin, A. S.

    2011-10-01

    The implosions of Stainless Steel (SS) Wire Arrays are extensively studied at SNL and also have applications in astrophysics. The analysis of radiation from low-number-wire SS Single and Nested Cylindrical, and Planar Wire Array experiments on the 1 MA Zebra is presented. The major focus is on x-ray imaging and spectra, total radiation yields, and fast, filtered x-ray detector data. The results of Leopard laser experiments with a flat 25 μm Fe target in the nanosecond (ns) and 350 femtosecond (fs) pulse regimes are discussed and compared with Z-pinch data. This comparison focuses mainly on L-shell Fe radiation and provides an excellent benchmark to the Z-pinch results. Good agreement with laser data is demonstrated in the ns regime, but a substantial difference is observed for the fs pulse. This work was supported by NNSA under DOE Coop. Agreements DE-FC52-06NA27588, 27586, and 27616. SNL is a multi-program laboratory managed and operated by Sandia Corp., a wholly owned subsidiary of Lockheed Martin Co., for the U.S. DOE under Contract DE-AC04-94AL85000.

  8. Benchmark Quantum Mechanical Calculations of Vibrationally Resolved Cross Sections and Rate Constants on ab Initio Potential Energy Surfaces for the F + HD Reaction: Comparisons with Experiments.

    PubMed

    De Fazio, Dario; Cavalli, Simonetta; Aquilanti, Vincenzo

    2016-07-14

    Quantum scattering calculations within the time-independent approach in an extended interval of energies were performed for the title reaction on four ab initio potential energy surfaces. The calculated integral cross sections, vibrational branching ratios, and rate constants are compared with scattering experiments as well as with chemical kinetics rate data available for this system for both the HF and DF channels. The calculations on the CSZ (J. Chem. Phys. 2015, 142, 024303) and LWAL (J. Chem. Phys. 2007, 127, 174302) surfaces are in close agreement between them and reproduce satisfactorily the experimental measurements. The agreement with the experiments is improved with respect to calculations on the earlier SW (J. Chem. Phys. 1996, 104, 6515) and FXZ (J. Chem. Phys. 2008, 129, 011103) surfaces. The results presented here witness the remarkable progress made by quantum chemistry calculations in describing the interatomic interactions governing the dynamics and kinetics of this reaction. They also suggest that comparison with translationally and rotationally averaged experimental observables is not sufficient to assess the relative accuracy of highly accurate potential energy surfaces. The dynamics and kinetics calculations show that temperatures lower than 50 K or molecular beam energy spread below 1 meV must be reached to discriminate the accuracy of the LWAL and the CSZ surfaces.

  9. Investigation of capillary nanosecond discharges in air at moderate pressure: comparison of experiments and 2D numerical modelling

    NASA Astrophysics Data System (ADS)

    Klochko, Andrei V.; Starikovskaia, Svetlana M.; Xiong, Zhongmin; Kushner, Mark J.

    2014-09-01

    Nanosecond electrical discharges in the form of ionization waves are of interest for rapidly ionizing and exciting complex gas mixtures to initiate chemical reactions. Operating with a small discharge tube diameter can significantly increase the specific energy deposition and so enable optimization of the initiation process. Analysis of the uniformity of energy release in small diameter capillary tubes will aid in this optimization. In this paper, results for the experimentally derived characteristics of nanosecond capillary discharges in air at moderate pressure are presented and compared with results from a two-dimensional model. The quartz capillary tube, having inner and outer diameters of 1.5 and 3.4 mm, is about 80 mm long and filled with synthetic dry air at 27 mbar. The capillary tube with two electrodes at the ends is inserted into a break of the central wire of a long coaxial cable. A metal screen around the tube is connected to the cable ground shield. The discharge is driven by a 19 kV 35 ns voltage pulse applied to the powered electrode. The experimental measurements are conducted primarily by using a calibrated capacitive probe and back current shunts. The numerical modelling focuses on the fast ionization wave (FIW) and the plasma properties in the immediate afterglow after the conductive plasma channel has been established between the two electrodes. The FIW produces a highly focused region of electric field on the tube axis that sustains the ionization wave that eventually bridges the electrode gap. Results from the model predict FIW propagation speed and current rise time that agree with the experiment.

  10. Correlated two-particle diffusion in dense colloidal suspensions at early times: Theory and comparison to experiment.

    PubMed

    Dell, Zachary E; Tsang, Boyce; Jiang, Lingxiang; Granick, Steve; Schweizer, Kenneth S

    2015-11-01

    The spatially resolved diffusive dynamic cross correlations of a pair of colloids in dense quasi-two-dimensional monolayers of identical particles are studied experimentally and theoretically at early times where motion is Fickian. In very dense systems where strong oscillatory equilibrium packing correlations are present, we find an exponential decay of the dynamic cross correlations on small and intermediate length scales. At large separations where structure becomes random, an apparent power law decay with an exponent of approximately -2.2 is observed. For a moderately dense suspension where local structural correlations are essentially absent, this same apparent power law decay is observed over all probed interparticle separations. A microscopic nonhydrodynamic theory is constructed for the dynamic cross correlations which is based on interparticle frictional effects and effective structural forces. Hydrodynamics enters only via setting the very short-time single-particle self-diffusion constant. No-adjustable-parameter quantitative predictions of the theory for the dynamic cross correlations are in good agreement with experiment over all length scales. The origin of the long-range apparent power law is the influence of the constraint of fixed interparticle separation on the amplitude of the mean square force exerted on the two tagged particles by the surrounding fluid. The theory is extended to study high-packing-fraction 3D hard sphere fluids. The same pattern of an oscillatory exponential form of the dynamic cross correlation function is predicted in the structural regime, but the long-range tail decays faster than in monolayers with an exponent of -3.

  11. Dew Incidence: a Field Study (related to Corn) in Jeddah, Saudi Arabia with Comparisons to a Similar Experiment in Texas.

    NASA Astrophysics Data System (ADS)

    Al-Amodi, Ahmad Osman

    An experiment was designed, assembled and carried out at the Hada Al-Sham Experimental station in the dry western part of Saudi Arabia, to procure dew duration data at two different heights in a corn canopy, from the time of emergence (average plant heights about 30 cm) until harvest time (average height about 230 cm). Micrometeorological, together with canopy and additional environmental measurements, were taken to deduce the latent heat flux involved in dew onset and dry-off. The micrometeorological measurements included leaf and air temperatures, relative humidity, net radiation, wind speeds and direction, while other observations included canopy heights, leaf width, leaf area index (LAI), soil temperature, soil moisture, and dew duration. The energy balance approach (Penman-Monteith), along with boundary layer resistance theory around the leaf surface, were used to estimate the latent heat flux involved in the dew process. It was found that at the beginning of the season dew usually started to form on the lower part of the canopy at an average of three hours before it started to form in the upper part. On the other hand, as the canopy reached the mature stage, dew formation on the upper part of the canopy started an average of two hours before it started to form on the lower part. It took averages of one hour and an hour and half after sunrise, for the lower and upper part of the canopy to dry-off respectively. A linear regression analysis of the latent heat and environmental variables showed high correlations with net radiation, leaf and air temperatures, relative humidity, soil temperature at 2cm depth from top of the furrow at both canopy heights for the whole growing season, whereas wind speed showed high correlation for the upper part of the canopy only. It is suggested that many more studies are necessary to increase understanding of the dew process but less comprehensive instrumentation would probably be adequate.

  12. Comparison of pharmacist and public views and experiences of community pharmacy medicines-related services in England

    PubMed Central

    Rodgers, Ruth M; Gammie, Shivaun M; Loo, Ruey Leng; Corlett, Sarah A; Krska, Janet

    2016-01-01

    Background Services provided by community pharmacists designed to support people using medicines are increasing. In England, two national services exist: Medicine Use Reviews (MUR) and New Medicines Service (NMS). Very few studies have been conducted seeking views of the public, rather than service users, on willingness to use these services or expectations of these services, or determined whether views align with pharmacist perceptions. Objective To compare the perceptions of pharmacists and the general public on medicines-related services, particularly MUR and NMS services. Methods Two parallel surveys were conducted in one area of England: one involved the general public and was administered using a street survey, and the other was a postal survey of community pharmacists. Similar questionnaires were used, seeking views of services, awareness, reasons for using services, and perceived benefits. Results Response rates were 47.2% (1,000/2,012 approached) for the public and 40.8% (341/836) for pharmacists. Few people had experienced a discussion in a private consultation room or were aware of the two formal services, although their willingness to use them was high. Pharmacists estimated time spent on service provision as 10 minutes for MUR and 12 minutes for NMS, which aligned with acceptability to both pharmacists and the public. Pharmacists underestimated the willingness of the public to wait for an informal discussion or to make appointments for formal services. Both pharmacists and the public had high expectations that services would be beneficial in terms of increasing knowledge and understanding, but public expectations and experiences of services helping to sort out problems fell well below pharmacists’ perceptions. People who had experienced a pharmacy service had different perceptions of pharmacists. Conclusion Views differed regarding why people use services and key aspects of service delivery. For services to improve, the pharmacy profession needs a

  13. Impact of dilution on microbial community structure and functional potential: comparison of numerical simulations and batch culture experiments

    NASA Technical Reports Server (NTRS)

    Franklin, R. B.; Garland, J. L.; Bolster, C. H.; Mills, A. L.

    2001-01-01

    A series of microcosm experiments was performed using serial dilutions of a sewage microbial community to inoculate a set of batch cultures in sterile sewage. After inoculation, the dilution-defined communities were allowed to regrow for several days and a number of community attributes were measured in the regrown assemblages. Based upon a set of numerical simulations, community structure was expected to differ along the dilution gradient; the greatest differences in structure were anticipated between the undiluted-low-dilution communities and the communities regrown from the very dilute (more than 10(-4)) inocula. Furthermore, some differences were expected among the lower-dilution treatments (e.g., between undiluted and 10(-1)) depending upon the evenness of the original community. In general, each of the procedures used to examine the experimental community structures separated the communities into at least two, often three, distinct groups. The groupings were consistent with the simulated dilution of a mixture of organisms with a very uneven distribution. Significant differences in community structure were detected with genetic (amplified fragment length polymorphism and terminal restriction fragment length polymorphism), physiological (community level physiological profiling), and culture-based (colony morphology on R2A agar) measurements. Along with differences in community structure, differences in community size (acridine orange direct counting), composition (ratio of sewage medium counts to R2A counts, monitoring of each colony morphology across the treatments), and metabolic redundancy (i.e., generalist versus specialist) were also observed, suggesting that the differences in structure and diversity of communities maintained in the same environment can be manifested as differences in community organization and function.

  14. Comparison of five soil organic matter decomposition models using data from a 14C and 15N labeling field experiment

    NASA Astrophysics Data System (ADS)

    Pansu, Marc; Bottner, Pierre; Sarmiento, Lina; Metselaar, Klaas

    2004-12-01

    Five alternatives of the previously published MOMOS model (MOMOS-2 to -6) are tested to predict the dynamics of carbon (C) and nitrogen (N) in soil during the decomposition of plant necromass. 14C and 15N labeled wheat straw was incubated over 2 years in fallow soils of the high Andean Paramo of Venezuela. The following data were collected: soil moisture, total 14C and 15N and microbial biomass (MB)-14C and -15N, daily rainfall, air temperature and total radiation. Daily soil moisture was predicted using the SAHEL model. MOMOS-2 to -4 (type 1 models) use kinetic constants and flow partitioning parameters. MOMOS-2 can be simplified to MOMOS-3 and further to MOMOS-4, with no significant changes in the prediction accuracy and robustness for total-14C and -15N as well as for MB-14C and -15N. MOMOS-5 (type 2 models) uses only kinetic constants: three MB-inputs (from labile and stable plant material and from humified compounds) and two MB-outputs (mortality and respiration constants). MOMOS-5 did not significantly change the total-14C and -15N predictions but markedly improved the predictive quality and robustness of MB-14C and -15N predictions (with a dynamic different from the predictions by other models). Thus MOMOS-5 is proposed as an accurate and ecologically consistent description of decomposition processes. MOMOS-6 extends MOMOS-5 by including a stable humus compartment for long-term simulations of soil native C and N. The improvement of the predictions is not significant for this 2-year experiment, but MOMOS-6 enables prediction of a sequestration in the stable humus compartment of 2% of the initially added 14C and 5.4% of the added 15N.

  15. Injustice Experience Questionnaire, Japanese Version: Cross-Cultural Factor-Structure Comparison and Demographics Associated with Perceived Injustice

    PubMed Central

    Adachi, Tomonori; Mibu, Akira; Nishigami, Tomohiko; Motoyama, Yasushi; Uematsu, Hironobu; Matsuda, Yoichi; Sato, Hitoaki; Hayashi, Kenichi; Cui, Renzhe; Takao, Yumiko; Shibata, Masahiko; Iso, Hiroyasu

    2016-01-01

    Objective The Injustice Experience Questionnaire (IEQ) assesses injury-related perceived injustice. This study aimed to (1) develop a Japanese version (IEQ-J), (2) examine its factor structure, validity, and reliability, and (3) discover which demographic variable(s) positively contributed to prediction of IEQ-J scores. Methods Data from 71 patients (33 male, 38 female; age = 20+) with injury pain were employed to investigate factor structure by exploratory and confirmatory factor analyses. Concurrent validity was examined by Pearson correlation coefficients among the IEQ-J, Brief Pain Inventory (BPI), and Pain Catastrophizing Scale (PCS). Internal consistency was investigated by Cronbach’s alpha, and test-retest reliability was indicated with intra-class correlations (ICCs) in 42 of 71 patients within four weeks. Relations between demographic variables and IEQ-J scores were examined by covariance analysis and linear regression models. Results IEQ-J factor structure differed from the original two-factor model. A three-factor model with Severity/irreparability, Blame/unfairness, and Perceived lack of empathy was extracted. The three-factor model showed goodness-of-fit with the data and sufficient reliability (Cronbach’s alpha of 0.90 for total IEQ-J; ICCs = 0.96). Pearson correlation coefficients among IEQ-J, BPI, and PCS ranged from 0.38 to 0.73. Pain duration over a year (regression coefficient, 11.92, 95%CI; 5.95–17.89) and liability for injury on another (regression coefficient, 12.17, 95%CI; 6.38–17.96) predicted IEQ-J total scores. Conclusions This study evidenced the IEQ-J’s sound psychometric properties. The three-factor model was the latter distinctive in the Japanese version. Pain duration over a year and injury liability by another statistically significantly increased IEQ-J scores. PMID:27487288

  16. Comparison of pharmacist and public views and experiences of community pharmacy medicines-related services in England

    PubMed Central

    Rodgers, Ruth M; Gammie, Shivaun M; Loo, Ruey Leng; Corlett, Sarah A; Krska, Janet

    2016-01-01

    Background Services provided by community pharmacists designed to support people using medicines are increasing. In England, two national services exist: Medicine Use Reviews (MUR) and New Medicines Service (NMS). Very few studies have been conducted seeking views of the public, rather than service users, on willingness to use these services or expectations of these services, or determined whether views align with pharmacist perceptions. Objective To compare the perceptions of pharmacists and the general public on medicines-related services, particularly MUR and NMS services. Methods Two parallel surveys were conducted in one area of England: one involved the general public and was administered using a street survey, and the other was a postal survey of community pharmacists. Similar questionnaires were used, seeking views of services, awareness, reasons for using services, and perceived benefits. Results Response rates were 47.2% (1,000/2,012 approached) for the public and 40.8% (341/836) for pharmacists. Few people had experienced a discussion in a private consultation room or were aware of the two formal services, although their willingness to use them was high. Pharmacists estimated time spent on service provision as 10 minutes for MUR and 12 minutes for NMS, which aligned with acceptability to both pharmacists and the public. Pharmacists underestimated the willingness of the public to wait for an informal discussion or to make appointments for formal services. Both pharmacists and the public had high expectations that services would be beneficial in terms of increasing knowledge and understanding, but public expectations and experiences of services helping to sort out problems fell well below pharmacists’ perceptions. People who had experienced a pharmacy service had different perceptions of pharmacists. Conclusion Views differed regarding why people use services and key aspects of service delivery. For services to improve, the pharmacy profession needs a

  17. Temperature and pressure retrievals from the Atmospheric Chemistry Experiment (ACE): a new technique and comparison with COSMIC

    NASA Astrophysics Data System (ADS)

    Olsen, Kevin; Strong, Kimberly; Toon, Geoff; Boone, Chris

    We present results of a new technique to retrieve temperature and pressure profiles from satellite remote sensing spectra collected by the Canadian Space Agency's (CSA) Atmospheric Chemistry Experiment (ACE), which recently celebrated its tenth year in orbit. ACE utilizes a high-resolution (0.02 cm (-1) ) Fourier Transform Spectrometer (FTS) operating between 750-4400 cm (-1) in limb-scanning mode using the sun as a light source (solar occultation). This technique benefits from high signal strength, high resolution, and self calibration. The CSA and NASA's Jet Propulsion Laboratory (JPL) developed a proposal to send a similar instrument to Mars: the Mars Atmospheric Trace Molecule Occultation Spectrometer (MATMOS, later canceled). To support this we have developed a new set of retrieval algorithms based on GGG used by the Total Carbon Column Observing Network (TCCON) and have applied these algorithms to ACE-FTS data. When performing temperature retrievals, the current approach of the ACE team is to fix the volume mixing ratio of CO_2 and carry out spectral fitting, varying temperature. While this method works very well and has been well validated, it relies on several assumptions, emph{a priori} knowledge, and data from models. Operating at another planet, these emph{a priori} are unknown and the models have not been developed to a suitable level. We demonstrate that by analyzing vibration-rotation bands of CO_2, we can retrieve vertical profiles of both temperature and pressure. Our retrieved temperature profiles are compared to those from ACE and the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC), and are used to retrieve volume mixing ratio vertical profiles for several gases, such as methane. The effects that variability in temperature and pressure have on retrieved VMR profiles is shown and retrieved VMR profiles are compared with those from ACE.

  18. A comparison of different transarterial embolization techniques for direct carotid cavernous fistulas: a single center experience in 32 patients

    PubMed Central

    Lu, Xiaojian; Hussain, Mohammed; Ni, Lanchun; Huang, Qinfeng; Zhou, Fei; Gu, Zhikai; Chen, Jian; Ding, Yuchuan; Xu, Feng

    2014-01-01

    Objective Transarterial treatment of direct carotid cavernous fistulas (DCCF) via embolic materials has been well documented. This study reports, validates, and compares with existing literature our experience treating DCCFs via endovascular approaches by using detachable balloons, coils, and covered stents. Methods Between June 2006 to October 2011, 32 patients (21 male, 11 female) with 32 DCCFs (30 traumatic, 2 spontaneous cavernous ICA aneurysms) were embolized endovascularly. Followup was performed for at least 6 months. Results Among the 32 DCCFs, 21 (65.6%) were embolized using detachable balloons, eight (25.0%) with coils, one (3.1%) with balloons and coils, and two (6.3%) with covered stents. Complete DCCF obliteration was achieved in 31 (96.9%) cases. One fistula failed to respond due to premature balloon detachment. Intracranial bruit in 31 (100%) chemosis and exophthalmos in 28 (100%) cases resolved after embolization. Visual acuity and oculomotor palsy improved in 18 (90%) and 18 (69.2%) cases, respectively. There was no evidence of DCCF recurrence. Thirteen DCCFs were followed up by MRI and five by DSA. In these cases, four (4/13, 30.8%) balloon-embolized DCCFs showed pseudoaneurysms. Three patients were asymptomatic; one had minor left oculomotor palsy. Conclusions Our results correlate and reinforce literature regarding endovascular treatment of DCCFs. Application of Transarterial embolization with detachable balloons, despite extensive use has been decreasing. Coil embolization is an effective and safe alternative for treatment, especially when balloon embolization fails. Covered stent placement may be used as another alternative for selected cases. PMID:25566340

  19. Aspect ratio effects on neoclassical tearing modes from comparison between DIII-D and National Spherical Torus Experiment

    SciTech Connect

    La Haye, R. J.; Buttery, R. J.; Gerhardt, S. P.; Sabbagh, S. A.; Brennan, D. P.

    2012-06-15

    Neoclassical tearing mode islands are sustained by helically perturbed bootstrap currents arising at finite beta from toroidal effects that trap a fraction of the particles in non-circulating orbits. DIII-D and NSTX are here operated with similar shape and cross-sectional area but almost a factor of two difference in inverse aspect ratio a/R. In these experiments, destabilized n=1 tearing modes were self-stabilized (reached the 'marginal point') by reducing neutral-beam power and thus beta. The measure of the marginal island gives information on the small-island stabilizing physics that in part (with seeding) governs onset. The marginal island width on NSTX is found to be about three times the ion banana width and agrees with that measured in DIII-D, except for DIII-D modes closer to the magnetic axis, which are about two times the ion banana width. There is a balance of the helically perturbed bootstrap term with small island effects with the sum of the classical and curvature terms in the modified Rutherford equation for tearing-mode stability at the experimental marginal point. Empirical evaluation of this sum indicates that while the stabilizing effect of the curvature term is negligible in DIII-D, it is important in NSTX. The mode temporal behavior from the start of neutral-beam injection reduction also suggests that NSTX operates closer to marginal classical tearing stability; this explains why there is little hysteresis in beta between mode onset, saturation, and self-stabilization (while DIII-D has large hysteresis in beta). NIMROD code module component calculations based on DIII-D and NSTX reconstructed experimental equilibria are used to diagnose and confirm the relative importance of the stabilizing curvature effect, an advantage for low aspect ratio; the relatively greater curvature effect makes for less susceptibility to NTM onset even if the classical tearing stability index is near marginal.

  20. Effects of high angular momentum on the unimolecular dissociation of CD2CD2OH: theory and comparisons with experiment.

    PubMed

    McKown, Benjamin G; Ceriotti, Michele; Womack, Caroline C; Kamarchik, Eugene; Butler, Laurie J; Bowman, Joel M

    2013-10-24

    This paper explores the dynamics of a highly rotationally and vibrationally excited radical, CD2CD2OH. The radical is produced from the 193 nm photodissociation of 2-bromoethanol-d4, so it is imparted with high angular momentum and high vibrational energy and subsequently dissociates to several product channels. This paper focuses on characterizing its angular momentum and modeling its effect on the product channels, including the HOD + vinyl-d3 product channel resulting from a frustrated dissociation of the radical originally en route to OH + ethene-d4 that instead results in D atom abstraction. Our impulsive model of the initial photodissociation shows that, for some cases, upward of 200 au of angular momentum is imparted, which greatly affects the dynamics of the competing product channels. Using a permutationally invariant potential energy surface and quasiclassical trajectories, we simulated the dissociation dynamics of CD2CD2OH and compared these results to those of Kamarchik et al. (J. Phys. Chem. Lett. 2010, 1, 3058-3065), who studied the dynamics of CH2CH2OH with zero angular momentum. We found that the recoil translational energy distribution for radicals that dissociated to OH + C2D4 matched experiment closely only when high angular momentum of the initial radical was explicitly included in the trajectory calculations. Similarly, the rate constant for dissociation changes when rotational energy was added to the vibrational energy in the initial conditions. Lastly, we applied the sketch-map dimensionality reduction technique to analyze mechanistic information leading to the vinyl + water product channel. Projecting the ab initio intrinsic reaction coordinates onto the lower dimensional space identified with sketch map offers new insight into the dynamics when one looks at the simulated trajectories in the lower dimensional space. Further analysis shows that the transition path resembles a frustrated dissociation of the OH + ethene radical adduct, followed

  1. Long-term experience with subcutaneous ICD leads: a comparison among three different types of subcutaneous leads.

    PubMed

    Kettering, Klaus; Mewis, Christian; Dörnberger, Volker; Vonthein, Reinhard; Bosch, Ralph F; Seipel, Ludger; Kühlkamp, Volker

    2004-10-01

    ICDs provide protection against sudden cardiac death in patients with life-threatening arrhythmias. Nevertheless, efficacy of defibrillation remains an important issue to guarantee the future safety of patients who receive an ICD. There is a significant number of patients who need an additional subcutaneous lead to obtain a defibrillation safety margin of at least 10 J between the maximum output of the ICD and the energy needed for ventricular defibrillation. However, few data exists about the long-term performance of different types of subcutaneous leads. Therefore, the aim of this study was to analyze the long-term experience with three different types of subcutaneous leads. The study included 132 patients (109 men, 23 women; mean age 59.8 years [SD +/- 10.7 years]). All of them received a subcutaneous lead in addition to a single chamber or dual chamber ICD between October 1990 and April 2002. Two patients received a second subcutaneous lead after the first lead had been removed so that a total of 134 subcutaneous leads were evaluated. Inclusion criteria for the implantation of an additional subcutaneous lead were (1) unsuccessful ventricular defibrillation at implant without a subcutaneous lead, (2) insufficient safety margin (< 10 J) between the maximum output of the ICD and the energy needed for ventricular defibrillation, or (3) clinical evaluation of a new subcutaneous lead (Medtronic 13014). There were no significant differences between the three study groups with regard to age, sex, underlying cardiac disease, left ventricular ejection fraction, NYHA class assessment and clinical arrhythmia. The results of the DFT testing during follow-up (prehospital discharge test and 1 and 3 years) were compared to the baseline value obtained during the implantation procedure. All lead related complications were analyzed. Eighty-two single element subcutaneous array electrodes (SQ-A1), 31 subcutaneous three-finger electrodes (SQ-A3), and 21 subcutaneous patch

  2. Comparison of aromatic hydrocarbon measurements made by PTR-MS, DOAS and GC-FID in Mexico City during the MCMA 2003 field experiment

    NASA Astrophysics Data System (ADS)

    Jobson, B. T.; Volkamer, R.; Velasco, E.; Allwine, G.; Westberg, H.; Lamb, B.; Alexander, M. L.; Berkowitz, C. M.; Molina, L. T.

    2009-09-01

    A comparison of aromatic hydrocarbon measurements is reported for the CENICA supersite in the district of Iztapalapa during the Mexico City Metropolitan Area field experiment in April 2003 (MCMA 2003). Data from three different measurement methods were compared, a proton transfer reaction mass spectrometer (PTR-MS), long path measurements using a UV differential optical absorption spectrometer (DOAS), and gas chromatography-flame ionization analysis (GC-FID) of canister samples. Lab tests established that the PTR-MS and DOAS calibrations were consistent for a suite of aromatic compounds including benzene, toluene, p-xylene, ethylbenzene, 1,2,4-trimethylbenzene, phenol, and styrene. The point sampling measurements by the PTR-MS and GC-FID showed good correlations (r=0.6), and were in reasonable agreement for toluene, C2-alkylbenzenes, and C3-alkylbenzenes. The PTR-MS benzene data were consistently high, indicating potential interference from fragmenting alkyl aromatics for the 145 Td drift field intensity used in the experiment. Correlations between the open-path data measured at 16-m height over a 860 m path length (retroreflector in 430 m distance), and the point measurements collected at 37-m sampling height were best for benzene (r=0.61), and reasonably good for toluene, C2-alkylbenzenes, naphthalene, styrene, cresols and phenol (r>0.5). While the DOAS data agreed within 20% with both point measurements for benzene, concentrations measured by DOAS were on average a factor of 1.7 times greater than the PTRMS data for toluene, C2-alkylbenzenes, naphthalene, and styrene. The level of agreement for the toluene data was a function of wind direction, establishing that spatial gradients - horizontal, vertical, or both - in VOC mixing ratios were significant, and up to a factor of 2 despite the fact that all measurements were conducted above roof level. Our analysis highlights a potential problem in defining a VOC sampling strategy that is meaningful for comparison with

  3. Onset of the summer monsoon during the FGGE 1979 experiment off the East African Coast: A comparison of wind data collected by different means

    SciTech Connect

    Schott, F.; Partagas, J.F.

    1981-05-20

    During FGGE 1979, from March to July, an extensive oceanographic experiment with ships and moored stations was carried out in the Somali Current. The development of the monsoon winds off Somalia during the time of that experiment is described in a comparative analysis of standard ship wind observations, moored buoy wind measurements, low-level cloud winds, and winds from land stations. The onset 1979 is found to be of the multiple type, with northward winds off Somalia beginning around May 5 but dying down into early June; the real onset of sustained high winds starts around June 10. Cloud level wind observation numbers off Somalia decrease drastically with the monsoon onset because of lack of clouds over the quickly developing cold upwelling areas. An intercomparison of cloud level and ship winds for the period May 16 to July 6 at five offshore points shows good agreement in directions but reduction of ship wind speeds against cloud level winds off northern Somalia after the onset, which may explained by the increased vertical wind shear due to high air stability over the upwelled water and by geostrophic shear due to the strong gradients of sea surface temperature. A comparison of 3-day averages of buoy winds measured at 3-m height 30 km offshore, but still inland from the ship lane, with ship winds for the period March 3 to June 10 showed good agreement in directions but lower buoy wind speeds, which could partly be due to sensor height difference and partly due to horizontal wind shear towards the coast. Coastal stations and wind buoys near the coast are found not to be good indicators of the monsoon onset further out in the open ocean.

  4. Flutter of a uniform wing with an arbitrarily placed mass according to a differential-equation analysis and a comparison with experiment

    NASA Technical Reports Server (NTRS)

    Runyan, Harry L; Watkins, Charles E

    1950-01-01

    A method is presented for the calculation of the flutter speed of a uniform wing carrying an arbitrarily placed concentrated mass. The method, an extension of recently published work by Goland and Luke, involves the solution of the differential equations of motion of the wing at flutter speed and therefore does not require the assumption of specific normal modes of vibration. The order of the flutter determinant to be solved by this method depends upon the order of the system of differential equations and not upon the number of modes of vibration involved. The differential equations are solved by operational methods, and a brief discussion of operational methods as applied to boundary-value problems is included in one of two appendixes. A comparison is made with experiment for a wing with a large eccentrically mounted weight and good agreement is obtained. Sample calculations are presented to illustrate the method; and curves of amplitudes of displacement, torque, and shear for a particular case are compared with corresponding curves computed from the first uncoupled normal modes.

  5. Comparison of methods for simultaneous identification of bacterial species and determination of metabolic activity by protein-based stable isotope probing (Protein-SIP) experiments.

    PubMed

    Jehmlich, Nico; Schmidt, Frank; Taubert, Martin; Seifert, Jana; von Bergen, Martin; Richnow, Hans-Hermann; Vogt, Carsten

    2009-06-01

    We developed a concept for analysing carbon and nitrogen fluxes in microbial communities by employing protein-based stable isotope probing (Protein-SIP) in metabolic labelling experiments with stable isotope labelled substrates. For identification of microbial species intact protein profiling (IPP) can be used, whereas the assessment of their metabolic activity is achieved by shotgun mass mapping (SMM). Microbial cultures were grown on substrates containing (13)C or (15)N. For identification of species we tested both the IPP and the SMM approaches. Mass spectra (MALDI-MS) were taken from mixtures of either intact proteins or peptides from tryptic digestion for generating species-specific peak patterns. In the case of SMM, the fragmentation of peptides was additionally used to obtain sequence information for species identification. Mass spectra of peptide sequences allow calculation of the amount of (13)C or (15)N incorporation within peptides for determining metabolic activity of the specific species. The comparison of IPP and SMM revealed a higher robustness of species identification by SMM. In addition, the assessment of incorporation levels of (13)C and (15)N into peptides by SMM revealed a lower uncertainty (0.5-0.8 atom %) compared to IPP (6.4-8.9 atom %). The determination of metabolic activity and function of individual species by Protein-SIP can help to analyse carbon and nitrogen fluxes within microbial communities.

  6. Simulations of the quart (101-bar1)/water interface: A comparison of classical force fields, ab initi molecular dynamics, and x-ray reflectivity experiments.

    SciTech Connect

    Skelton, Adam; Fenter, Paul; Kubicki, James D.; Wesolowski, David J; Cummings, Peter T

    2011-01-01

    Classical molecular dynamics (CMD) simulations of the (1011) surface of quartz interacting with bulk liquid water are performed using three different classical force fields, Lopes et al., ClayFF, and CHARMM water contact angle (CWCA), and compared to ab initio molecular dynamics (AIMD) and X-ray reflectivity (XR) results. The axial densities of the water and surface atoms normal to the surface are calculated and compared to previous XR experiments. Favorable agreement is shown for all the force fields with respect to the position of the water atoms. Analyses such as the radial distribution functions between water and hydroxyl atoms and the average cosine of the angle between the water dipole vector and the normal of the surface are also calculated for each force field. Significant differences are found between the different force fields from such analyses, indicating differing descriptions of the structured water in the near vicinity of the surface. AIMD simulations are also performed to obtain the water and hydroxyl structure for comparison among the predictions of the three classical force fields to better understand which force field is most accurate. It is shown that ClayFF exhibits the best agreement with the AIMD simulations for water hydroxyl radial distribution functions, suggesting that ClayFF treats the hydrogen bonding more accurately.

  7. Comparison of the LLNL ALE3D and AKTS Thermal Safety Computer Codes for Calculating Times to Explosion in ODTX and STEX Thermal Cookoff Experiments

    SciTech Connect

    Wemhoff, A P; Burnham, A K

    2006-04-05

    Cross-comparison of the results of two computer codes for the same problem provides a mutual validation of their computational methods. This cross-validation exercise was performed for LLNL's ALE3D code and AKTS's Thermal Safety code, using the thermal ignition of HMX in two standard LLNL cookoff experiments: the One-Dimensional Time to Explosion (ODTX) test and the Scaled Thermal Explosion (STEX) test. The chemical kinetics model used in both codes was the extended Prout-Tompkins model, a relatively new addition to ALE3D. This model was applied using ALE3D's new pseudospecies feature. In addition, an advanced isoconversional kinetic approach was used in the AKTS code. The mathematical constants in the Prout-Tompkins code were calibrated using DSC data from hermetically sealed vessels and the LLNL optimization code Kinetics05. The isoconversional kinetic parameters were optimized using the AKTS Thermokinetics code. We found that the Prout-Tompkins model calculations agree fairly well between the two codes, and the isoconversional kinetic model gives very similar results as the Prout-Tompkins model. We also found that an autocatalytic approach in the beta-delta phase transition model does affect the times to explosion for some conditions, especially STEX-like simulations at ramp rates above 100 C/hr, and further exploration of that effect is warranted.

  8. Comparison of OH concentration measurements by DOAS and LIF during SAPHIR chamber experiments at high OH reactivity and low NO concentration

    NASA Astrophysics Data System (ADS)

    Fuchs, H.; Dorn, H.-P.; Bachner, M.; Bohn, B.; Brauers, T.; Gomm, S.; Hofzumahaus, A.; Holland, F.; Nehr, S.; Rohrer, F.; Tillmann, R.; Wahner, A.

    2012-07-01

    During recent field campaigns, hydroxyl radical (OH) concentrations that were measured by laser-induced fluorescence (LIF) were up to a factor of ten larger than predicted by current chemical models for conditions of high OH reactivity and low NO concentration. These discrepancies, which were observed in forests and urban-influenced rural environments, are so far not entirely understood. In summer 2011, a series of experiments was carried out in the atmosphere simulation chamber SAPHIR in Jülich, Germany, in order to investigate the photochemical degradation of isoprene, methyl-vinyl ketone (MVK), methacrolein (MACR) and aromatic compounds by OH. Conditions were similar to those experienced during the PRIDE-PRD2006 campaign in the Pearl River Delta (PRD), China, in 2006, where a large difference between OH measurements and model predictions was found. During experiments in SAPHIR, OH was simultaneously detected by two independent instruments: LIF and differential optical absorption spectroscopy (DOAS). Because DOAS is an inherently calibration-free technique, DOAS measurements are regarded as a reference standard. The comparison of the two techniques was used to investigate potential artifacts in the LIF measurements for PRD-like conditions of OH reactivities of 10 to 30 s-1 and NO mixing ratios of 0.1 to 0.3 ppbv. The analysis of twenty experiment days shows good agreement. The linear regression of the combined data set (averaged to the DOAS time resolution, 2495 data points) yields a slope of 1.02 ± 0.01 with an intercept of (0.10 ± 0.03) × 106 cm-3 and a linear correlation coefficient of R2 = 0.86. This indicates that the sensitivity of the LIF instrument is well-defined by its calibration procedure. No hints for artifacts are observed for isoprene, MACR, and different aromatic compounds. LIF measurements were approximately 30-40% (median) larger than those by DOAS after MVK (20 ppbv) and toluene (90 ppbv) had been added. However, this discrepancy has a

  9. Comparison of OH concentration measurements by DOAS and LIF during SAPHIR chamber experiments at high OH reactivity and low NO concentration

    NASA Astrophysics Data System (ADS)

    Fuchs, H.; Dorn, H.-P.; Bachner, M.; Bohn, B.; Brauers, T.; Gomm, S.; Hofzumahaus, A.; Holland, F.; Nehr, S.; Rohrer, F.; Tillmann, R.; Wahner, A.

    2012-03-01

    During recent field campaigns, hydroxyl radical (OH) concentrations that were measured by laser-induced fluorescence (LIF) were up to a factor of ten larger than predicted by current chemical models for conditions of high OH reactivity and low NO concentration. These discrepancies, which were observed in forests and urban-influenced rural environments, are so far not entirely understood. In summer 2011, a series of experiments was carried out in the atmosphere simulation chamber SAPHIR in Jülich, Germany, in order to investigate the photochemical degradation of isoprene, methyl-vinyl ketone (MVK), methacrolein (MACR) and aromatic compounds by OH. Conditions were similar to those experienced during the PRIDE-PRD2006 campaign in the Pearl River Delta (PRD), China, in 2006, where a large difference between OH measurements and model predictions was found. During experiments in SAPHIR, OH was simultaneously detected by two independent instruments: LIF and differential optical absorption spectroscopy (DOAS). Because DOAS is an inherently calibration-free technique, DOAS measurements are regarded as a reference standard. The comparison of the two techniques was used to investigate potential artifacts in the LIF measurements for PRD-like conditions of OH reactivities of 10 to 30 s-1 and NO mixing ratios of 0.1 to 0.3 ppbv. The analysis of twenty experiment days shows good agreement. The linear regression of the combined data set (averaged to the DOAS time resolution, 2495 data points) yields a slope of 1.02 ± 0.01 with an intercept of (0.10 ± 0.03) ×106 cm-3 and a linear correlation coefficient of R2=0.86. This indicates that the sensitivity of the LIF instrument is well-defined by its calibration procedure. No hints for artifacts are observed for isoprene, MACR, and different aromatic compounds. LIF measurements were approximately 30-40% (median) larger than those by DOAS after MVK and toluene had been added. However, this discrepancy has a large uncertainty and

  10. Airborne Sunphotometer Measurements of Aerosol Optical Depth and Columnar Water Vapor During the Puerto Rico Dust Experiment, and Comparison with Land, Aircraft, and Satellite Measurements

    NASA Technical Reports Server (NTRS)

    Livingston, John M.; Russell, Philip B.; Reid, Jeffrey; Redemann, Jens; Schmid, Beat; Allen, Duane A.; Torres, Omar; Levy, Robert C.; Remer, Lorraine A.; Holben, Brent N.; Hipskind, R. Stephen (Technical Monitor)

    2002-01-01

    Analyses of aerosol optical depth (AOD) and columnar water vapor (CWV) measurements obtained with the six-channel NASA Ames Airborne Tracking Sunphotometer (AATS-6) mounted on a twin-engine aircraft during the summer 2000 Puerto Rico Dust Experiment are presented. In general, aerosol extinction values calculated from AATS-6 AOD measurements acquired during aircraft profiles up to 5 km ASL reproduce the vertical structure measured by coincident aircraft in-situ measurements of total aerosol number and surface area concentration. Calculations show that the spectral dependence of AOD was small (mean Angstrom wavelength exponents of approximately 0.20) within three atmospheric layers defined as the total column beneath the top of each aircraft profile, the region beneath the trade wind inversion, and the region within the Saharan Air Layer (SAL) above the trade inversion. This spectral behavior is consistent with attenuation of incoming solar radiation by large dust particles or by dust plus sea salt. Values of CWV calculated from profile measurements by AATS-6 at 941.9 nm and from aircraft in-situ measurements by a chilled mirror dewpoint hygrometer agree to within approximately 4% (0.13 g/sq cm). AATS-6 AOD values measured on the ground at Roosevelt Roads Naval Air Station and during low altitude aircraft runs over the adjacent Cabras Island aerosol/radiation ground site agree to within 0.004 to 0.030 with coincident data obtained with an AERONET Sun/sky Cimel radiometer located at Cabras Island. For the same observation times, AERONET retrievals of CWV exceed AATS-6 values by a mean of 0.74 g/sq cm (approximately 21 %) for the 2.9-3.9 g/sq cm measured by AATS-6. Comparison of AATS-6 aerosol extinction values obtained during four aircraft ascents over Cabras Island with corresponding values calculated from coincident aerosol backscatter measurements by a ground-based micro-pulse lidar (MPL-Net) located at Cabras yields a similar vertical structure above the trade

  11. Radar surface signatures for the two-dimensional tidal circulation over Phelps Bank, Nantucket shoals: A comparison between theory and experiment

    NASA Astrophysics Data System (ADS)

    Cooper, A. L.; Chubb, S. R.; Askari, F.; Valenzuela, G. R.; Bennett, J. R.; Keller, W. C.

    1994-04-01

    A comparison is made between real aperture radar (RAR) measurements and simulations (based on modeled tidal currents) of radar cross section over a complicated tidal basin (in the vicinity of the Phelps Bank region of the Nantucket shoals) in order to more fully understand the origin of radar signatures that are observed at the ocean surface as a consequence of variations in the topography of the ocean bottom. The Phelps Bank region was mapped under two extreme wind speed conditions: in high winds, in excess of 15 m/s, and in low winds, of the order of 2-3 m/s. For the light-wind case the measured radar cross section over the west side of the Phelps Bank was enhanced by as much as 20 dB relative to the clutter background. For the high-wind case, no discernible bathymetric signature was found in the highclutter background. Numerical results for the two-dimensional M2 (semidiurnal) tidal currents over the Phelps Bank (Greenberg et al., 1989), with ⅛ × ⅛ min of arc resolution, are used as input to the surface signature models: the Alpers and Hennings (1984) first-order Bragg relaxation model; a generalized form of this relaxation model (in which wind directional effects are incorporated in an approximate manner); and the full-spectrum model of Lyzenga and Bennett (1988). Comparisons between the models (which do not include wave breaking) and an extreme case of 2-3 m/s winds (where strong wave breaking could become important) reveal that although the models predict correlation between variations in bottom topography and surface signature, they significantly underpredict the magnitude of the observed effect. The model calculations also are very sensitive at low (<2 m/s) wind speeds to the functional form that is assumed for the wind-wave forcing in the wave action equation. Prior visual observations and measurements of wave spectra (and wave shoaling) in the vicinity of Phelps Bank strongly suggest that the deficiencies of the modeled results that occur explicitly

  12. Comparison of first dimension IPG and NEPHGE techniques in two-dimensional gel electrophoresis experiment with cytosolic unfolded protein response in Saccharomyces cerevisiae

    PubMed Central

    2013-01-01

    Background Two-dimensional gel electrophoresis (2DE) is one of the most popular methods in proteomics. Currently, most 2DE experiments are performed using immobilized pH gradient (IPG) in the first dimension; however, some laboratories still use carrier ampholytes-based isoelectric focusing technique. The aim of this study was to directly compare IPG-based and non-equilibrium pH gradient electrophoresis (NEPHGE)-based 2DE techniques by using the same samples and identical second dimension procedures. We have used commercially available Invitrogen ZOOM IPGRunner and WITAvision systems for IPG and NEPHGE, respectively. The effectiveness of IPG-based and NEPHGE-based 2DE methods was compared by analysing differential protein expression during cytosolic unfolded protein response (UPR-Cyto) in Saccharomyces cerevisiae. Results Protein loss during 2DE procedure was higher in IPG-based method, especially for basic (pI > 7) proteins. Overall reproducibility of spots was slightly better in NEPHGE-based method; however, there was a marked difference when evaluating basic and acidic protein spots. Using Coomassie staining, about half of detected basic protein spots were not reproducible by IPG-based 2DE, whereas NEPHGE-based method showed excellent reproducibility in the basic gel zone. The reproducibility of acidic proteins was similar in both methods. Absolute and relative volume variability of separate protein spots was comparable in both 2DE techniques. Regarding proteomic analysis of UPR-Cyto, the results exemplified parameters of general comparison of the methods. New highly basic protein Sis1p, overexpressed during UPR-Cyto stress, was identified by NEPHGE-based 2DE method, whereas IPG-based method showed unreliable results in the basic pI range and did not provide any new information on basic UPR-Cyto proteins. In the acidic range, the main UPR-Cyto proteins were detected and quantified by both methods. The drawback of NEPHGE-based 2DE method is its failure to

  13. Petrophysical characterization of first ever drilled core samples from an active CO2 storage site, the German Ketzin Pilot Site - Comparison with long term experiments

    NASA Astrophysics Data System (ADS)

    Zemke, Kornelia; Liebscher, Axel

    2014-05-01

    Petrophysical properties like porosity and permeability are key parameters for a safe long-term storage of CO2 but also for the injection operation itself. These parameters may change during and/or after the CO2 injection due to geochemical reactions in the reservoir system that are triggered by the injected CO2. Here we present petrophysical data of first ever drilled cores from a newly drilled well at the active CO2 storage site - the Ketzin pilot site in the Federal State of Brandenburg, Germany. By comparison with pre-injection baseline data from core samples recovered prior to injection, the new samples provide the unique opportunity to evaluate the impact of CO2 on pore size related properties of reservoir and cap rocks at a real injection site under in-situ reservoir conditions. After injection of 61 000 tons CO2, an additional well was drilled and new rock cores were recovered. In total 100 core samples from the reservoir and the overlaying caprock were investigated by NMR relaxation. Permeability of 20 core samples was estimated by nitrogen and porosity by helium pycnometry. The determined data are comparable between pre-injection and post-injection core samples. The lower part of the reservoir sandstone is unaffected by the injected CO2. The upper part of the reservoir sandstone shows consistently slightly lower NMR porosity and permeability values in the post-injection samples when compared to the pre-injection data. This upper sandstone part is above the fluid level and CO2 present as a free gas phase and a possible residual gas saturation of the cores distorted the NMR results. The potash-containing drilling fluid can also influence these results: NMR investigation of twin samples from inner and outer parts of the cores show a reduced fraction of larger pores for the outer core samples together with lower porosities and T2 times. The drill mud penetration depth can be controlled by the added fluorescent tracer. Due to the heterogeneous character of the

  14. A comparison between Nimbus 5 THIR and ITPR temperatures and derived winds with rawinsonde data obtained in the AVE II experiment. [Temperature-Humidity Infrared Radiometer and Infrared Temperature Profile Radiometer

    NASA Technical Reports Server (NTRS)

    Arnold, J. E.; Scoggins, J. R.; Fuelberg, H. E.

    1977-01-01

    During the second Atmospheric Variability Experiment (AVE II), atmospheric temperature profiles were computed from Nimbus 5 data, which comprised ITPR, NEMS, and SCR measurements. Rawinsonde data were obtained from NWS stations in the AVE II network and processed for each pressure contact; the soundings closest in space and time were interpolated to the Nimbus 5 sounding points for comparison purposes. Cross sections of thermal and geostrophic winds were computed from satellite-derived cross sections of temperature along the Nimbus orbital track.

  15. Analysis and comparison of diurnal variations of cloud radiative forcing: Earth Radiation Budget Experiment and International Satellite Cloud Climatology Project results

    NASA Technical Reports Server (NTRS)

    Kim, Yongseung

    1994-01-01

    Cloud radiative forcing (CRF) is the radiative impact of clouds on the Earth's radiation budget. This study examines the diurnal variations of CRF using the Earth Radiation Budget Experiment (ERBE) monthly hourly flux data and the flux data derived from the International Satellite Cloud Climatology Project (ISCCP) using the Goddard Institute for Space Studies general circulation model radiation code. The results for the months of April, July, and October 1985 and January 1986 are analyzed. We found that, in general, two data sets agreed. For longwave (LW) CRF the diurnal range over land is generally greater than that observed over oceans. For the 4-month averages the ERBE values are 15.8 W/sq m and 6.8 W/sq m for land and ocean, respectively, compared with the ISCCP calculated values of 18.4 W/sq m and 8.0 W/sq m, respectively. The land/ocean contrast is largely associated with changes in cloud amount and the temperature difference between surface and cloud top. It would be more important to note that the clear-sky flux (i.e., surface temperature) variabilities are shown to be a major contributor to the large variabilities over land. The maximum diurnal range is found to be in the summer hemisphere, and the minimum values in the winter hemisphere. It is also shown that the daytime maximum and the nighttime minimum are seen over large portions of land, whereas they occur at any local hour over most oceans. For shortwave (SW) CRF the daytime maximum values are about twice as large as monthly averages, and their highest frequency occurs at local noon, indicating that solar insolation is a primary factor for the diurnal variation of SW CRF. However, the comparison of the ERBE data with the ISCCP results demonstrated that the largest differences in the diurnal range and monthly mean of LW CRF were associated with tropical convergence zones, where clear-sky fluxes could be easily biased by persistent cloudiness and the inadequate treatment of the atmospheric water vapor.

  16. Latino College Students at Highly Selective Institutions: A Comparison of Their College Experiences and Outcomes to Other Racial/Ethnic Groups

    ERIC Educational Resources Information Center

    Kim, Young K.; Rennick, Liz A.; Franco, Marla A.

    2014-01-01

    This study examines unique patterns of college engagement and outcomes among Latino undergraduate students attending highly selective institutions in comparison with those from other racial/ethnic groups. The study also identifies predictors of select college outcomes--that is, cognitive, affective, and civic outcomes--for this population.…

  17. Ab initio analytical Raman intensities for periodic systems through a coupled perturbed Hartree-Fock/Kohn-Sham method in an atomic orbital basis. II. Validation and comparison with experiments

    NASA Astrophysics Data System (ADS)

    Maschio, Lorenzo; Kirtman, Bernard; Rérat, Michel; Orlando, Roberto; Dovesi, Roberto

    2013-10-01

    In this work, we validate a new, fully analytical method for calculating Raman intensities of periodic systems, developed and presented in Paper I [L. Maschio, B. Kirtman, M. Rérat, R. Orlando, and R. Dovesi, J. Chem. Phys. 139, 164101 (2013)]. Our validation of this method and its implementation in the CRYSTAL code is done through several internal checks as well as comparison with experiment. The internal checks include consistency of results when increasing the number of periodic directions (from 0D to 1D, 2D, 3D), comparison with numerical differentiation, and a test of the sum rule for derivatives of the polarizability tensor. The choice of basis set as well as the Hamiltonian is also studied. Simulated Raman spectra of α-quartz and of the UiO-66 Metal-Organic Framework are compared with the experimental data.

  18. Detection of the "cp4 epsps" Gene in Maize Line NK603 and Comparison of Related Protein Structures: An Advanced Undergraduate Experiment

    ERIC Educational Resources Information Center

    Swope, Nicole K.; Fryfogle, Patrick J.; Sivy, Tami L.

    2015-01-01

    A flexible, rigorous laboratory experiment for upper-level biochemistry undergraduates is described that focuses on the Roundup Ready maize line. The work is appropriate for undergraduate laboratory courses that integrate biochemistry, molecular biology, or bioinformatics. In this experiment, DNA is extracted and purified from maize kernel and…

  19. Transport Experiments

    NASA Technical Reports Server (NTRS)

    Hall, Timothy M.; Wuebbles, Donald J.; Boering, Kristie A.; Eckman, Richard S.; Lerner, Jean; Plumb, R. Alan; Rind, David H.; Rinsland, Curtis P.; Waugh, Darryn W.; Wei, Chu-Feng

    1999-01-01

    MM II defined a series of experiments to better understand and characterize model transport and to assess the realism of this transport by comparison to observations. Measurements from aircraft, balloon, and satellite, not yet available at the time of MM I [Prather and Remsberg, 1993], provide new and stringent constraints on model transport, and address the limits of our transport modeling abilities. Simulations of the idealized tracers the age spectrum, and propagating boundary conditions, and conserved HSCT-like emissions probe the relative roles of different model transport mechanisms, while simulations of SF6 and C02 make the connection to observations. Some of the tracers are related, and transport diagnostics such as the mean age can be derived from more than one of the experiments for comparison to observations. The goals of the transport experiments are: (1) To isolate the effects of transport in models from other processes; (2) To assess model transport for realistic tracers (such as SF6 and C02) for comparison to observations; (3) To use certain idealized tracers to isolate model mechanisms and relationships to atmospheric chemical perturbations; (4) To identify strengths and weaknesses of the treatment of transport processes in the models; (5) To relate evaluated shortcomings to aspects of model formulation. The following section are included:Executive Summary, Introduction, Age Spectrum, Observation, Tropical Transport in Models, Global Mean Age in Models, Source-Transport Covariance, HSCT "ANOY" Tracer Distributions, and Summary and Conclusions.

  20. Summarizing EC50 estimates from multiple dose-response experiments: a comparison of a meta-analysis strategy to a mixed-effects model approach.

    PubMed

    Jiang, Xiaoqi; Kopp-Schneider, Annette

    2014-05-01

    Dose-response studies are performed to investigate the potency of a compound. EC50 is the concentration of the compound that gives half-maximal response. Dose-response data are typically evaluated by using a log-logistic model that includes EC50 as one of the model parameters. Often, more than one experiment is carried out to determine the EC50 value for a compound, requiring summarization of EC50 estimates from a series of experiments. In this context, mixed-effects models are designed to estimate the average behavior of EC50 values over all experiments by considering the variabilities within and among experiments simultaneously. However, fitting nonlinear mixed-effects models is more complicated than in a linear situation, and convergence problems are often encountered. An alternative strategy is the application of a meta-analysis approach, which combines EC50 estimates obtained from separate log-logistic model fitting. These two proposed strategies to summarize EC50 estimates from multiple experiments are compared in a simulation study and real data example. We conclude that the meta-analysis strategy is a simple and robust method to summarize EC50 estimates from multiple experiments, especially suited in the case of a small number of experiments.

  1. The STD/MHD codes - Comparison of analyses with experiments at AEDC/HPDE, Reynolds Metal Co., and Hercules, Inc. [for MHD generator flows

    NASA Technical Reports Server (NTRS)

    Vetter, A. A.; Maxwell, C. D.; Swean, T. F., Jr.; Demetriades, S. T.; Oliver, D. A.; Bangerter, C. D.

    1981-01-01

    Data from sufficiently well-instrumented, short-duration experiments at AEDC/HPDE, Reynolds Metal Co., and Hercules, Inc., are compared to analyses with multidimensional and time-dependent simulations with the STD/MHD computer codes. These analyses reveal detailed features of major transient events, severe loss mechanisms, and anomalous MHD behavior. In particular, these analyses predicted higher-than-design voltage drops, Hall voltage overshoots, and asymmetric voltage drops before the experimental data were available. The predictions obtained with these analyses are in excellent agreement with the experimental data and the failure predictions are consistent with the experiments. The design of large, high-interaction or advanced MHD experiments will require application of sophisticated, detailed and comprehensive computational procedures in order to account for the critical mechanisms which led to the observed behavior in these experiments.

  2. Experiments with powdered CMN thermometers between 10 mK and 4K, and a comparison with an NBS SRM 768 fixed-point device

    SciTech Connect

    Fogle, W.E.; Hornung, E.W.; Mayberry, M.C.; Phillips, N.E.

    1981-08-01

    Comparison of a powdered CMN thermometer with an NBS fixed point device demonstrates an internal inconsistency in the T/sub c/'s assigned to the fixed point device. T/sub c/'s between 100 and 200 mK are in excellent agreement with a temperature scale interpolated between He vapor pressure temperatures and nuclear orientation temperatures, but there is a discrepancy of 8% at the 15 mK point. Evidence for different susceptibility-temperature relations for superficially similar CMN thermometers is also presented.

  3. Dissociative disorders and possession experiences in Israel: a comparison of opiate use disorder patients, Arab women subjected to domestic violence, and a nonclinical group.

    PubMed

    Somer, Eli; Ross, Colin; Kirshberg, Revital; Bakri, Rana Shawahdy; Ismail, Shefa

    2015-02-01

    This study examined the association between exposure to domestic violence and dissociative symptoms. A sample of 68 Israeli opiate use disorder patients in recovery, 80 battered Arab Israeli women, and 103 respondents from a community sample participated in structured interviews that included the Dissociative Disorders Interview Schedule (DDIS), the Dissociative Trance Disorder Interview Schedule (DTDIS), and the Dissociative Experiences Scale (DES). As predicted, community participants reported significantly less exposure to traumatizing events and lower levels of dissociative psychopathology than individuals sampled from specialized treatment centers. In all, 91% of battered female participants were taxon-positive for dissociative disorder with 1 of every 2 respondents reporting symptoms corresponding to dissociative amnesia and depersonalization disorder, suggesting that this group may be particularly vulnerable to dissociative psychopathology. Extrasensory and paranormal experiences (ESP) and dissociative trance disorder experiences were strongly related to dissociative experiences and features of dissociative identity disorder (DID). These statistical associations suggest that dissociative disorders and ESP/trance experiences may share an underlying construct. Further research is needed on trauma and dissociation among female victims of domestic abuse in patriarchal, collectivist societies, particularly in the Arab world. PMID:25300648

  4. Dissociative disorders and possession experiences in Israel: a comparison of opiate use disorder patients, Arab women subjected to domestic violence, and a nonclinical group.

    PubMed

    Somer, Eli; Ross, Colin; Kirshberg, Revital; Bakri, Rana Shawahdy; Ismail, Shefa

    2015-02-01

    This study examined the association between exposure to domestic violence and dissociative symptoms. A sample of 68 Israeli opiate use disorder patients in recovery, 80 battered Arab Israeli women, and 103 respondents from a community sample participated in structured interviews that included the Dissociative Disorders Interview Schedule (DDIS), the Dissociative Trance Disorder Interview Schedule (DTDIS), and the Dissociative Experiences Scale (DES). As predicted, community participants reported significantly less exposure to traumatizing events and lower levels of dissociative psychopathology than individuals sampled from specialized treatment centers. In all, 91% of battered female participants were taxon-positive for dissociative disorder with 1 of every 2 respondents reporting symptoms corresponding to dissociative amnesia and depersonalization disorder, suggesting that this group may be particularly vulnerable to dissociative psychopathology. Extrasensory and paranormal experiences (ESP) and dissociative trance disorder experiences were strongly related to dissociative experiences and features of dissociative identity disorder (DID). These statistical associations suggest that dissociative disorders and ESP/trance experiences may share an underlying construct. Further research is needed on trauma and dissociation among female victims of domestic abuse in patriarchal, collectivist societies, particularly in the Arab world.

  5. Comparison of batch, stirred flow chamber, and column experiments to study adsorption, desorption and transport of carbofuran within two acidic soils.

    PubMed

    Bermúdez-Couso, Alipio; Fernández-Calviño, David; Rodríguez-Salgado, Isabel; Nóvoa-Muñoz, Juan Carlos; Arias-Estévez, Manuel

    2012-06-01

    Different methods (batch, column and stirred flow chamber experiments) used for adsorption and desorption of carbofuran studies were compared. All tested methods showed that the carbofuran adsorption was higher in the soil with the higher organic matter content, whereas the opposite behaviour was observed for the percentage of carbofuran desorbed. However, different methods have revealed some discrepancies in carbofuran adsorption/desorption kinetics. Although batch method showed interesting data on equilibrium experiments, such as a low heterogeneity for the carbofuran adsorption sites independent of soil organic matter content, it had some disadvantages for carbofuran adsorption/desorption kinetic studies. The disadvantages were related with the excessive limitations of this method on kinetics, i.e., no difference could be detected between different soils. However, with column and stirred flow chamber methods the carbofuran adsorption/desorption kinetics of different soils could be compared. Moreover, the absolute values of carbofuran adsorption/desorption and its rate were higher in the stirred flow chamber than in the batch and column experiments. Using stirred flow chamber experiments the carbofuran desorption was significantly faster than its adsorption, whereas carbofuran using column experiments they were similar. These discrepancies should be considered when the results obtained only with one method is discussed.

  6. Near-field reflection backscattering apertureless optical microscopy: application to spectroscopy experiments on opaque samples, comparison between lock-in and digital photon counting detection techniques.

    PubMed

    Diziain, S; Bijeon, J-L; Adam, P-M; Lamy de la Chapelle, M; Thomas, B; Déturche, R; Royer, P

    2007-01-01

    An apertureless scanning near-field optical microscope (ASNOM) in reflection backscattering configuration is designed to conduct spectroscopic experiments on opaque samples constituted of latex beads. The ASNOM proposed takes advantage of the depth-discrimination properties of confocal microscopes to efficiently extract the near-field optical signal. Given their importance in a spectroscopic experiment, we systematically compare the lock-in and synchronous photon counting detection methods. Some results of Rayleigh's scattering in the near field of the test samples are used to illustrate the possibilities of this technique for reflection backscattering spectroscopy.

  7. Comparisons of Internet-Based and Face-to-Face Learning Systems Based on "Equivalency of Experiences" According to Students' Academic Achievements and Satisfactions

    ERIC Educational Resources Information Center

    Karatas, Sercin; Simsek, Nurettin

    2009-01-01

    The purpose of this study is to determine whether "equivalent learning experiences" ensure equivalency, in the Internet-based and face-to-face interaction methods on learning results and student satisfaction. In the experimental process of this study, the effect of the Internet-based and face-to-face learning on the equivalency in learning…

  8. A Comparison of the Employment Experiences of Childcare Workers in Non-Profit and Privately-Owned Childcare Centres: Some Preliminary Findings.

    ERIC Educational Resources Information Center

    Nuttall, Jocelyn Grace

    A comparative study of the employment experiences of staff at nonprofit and privately owned childcare centers was conducted in the Christchurch, New Zealand, area. A total of 23 staff members at 3 nonprofit centers and 9 staff members at 2 privately owned centers responded to a survey concerning their qualifications, work history, current working…

  9. A Comparison of the Developmental Experiences of Elite and Sub-Elite Swimmers: Similar Developmental Histories Can Lead to Differences in Performance Level

    ERIC Educational Resources Information Center

    Johnson, Michael B.; Tenenbaum, Gershon; Edmonds, William A.; Castillo, Yvonne

    2008-01-01

    The current study fills a void in the literature that investigates the factors required for elite athlete development. Previous studies have (a) illustrated psychological and physiological differences between elites and non-elites; "or" (b) described the psychological and physiological developmental experiences of elite performers. The current…

  10. Comparison of airborne passive and active L-band System (PALS) brightness temperature measurements to SMOS observations during the SMAP validation experiment 2012 (SMAPVEX12)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The purpose of SMAP (Soil Moisture Active Passive) Validation Experiment 2012 (SMAPVEX12) campaign was to collect data for the pre-launch development and validation of SMAP soil moisture algorithms. SMAP is a National Aeronautics and Space Administration’s (NASA) satellite mission designed for the m...

  11. Study Abroad in a Developing and a Developed Country: A Comparison of American Undergraduate Students' Experiences in Ghana and England

    ERIC Educational Resources Information Center

    Costa, Maria

    2012-01-01

    This qualitative study examined the differences among the experiences of 7 American undergraduate students; 4 who studied for a semester in Ghana, a developing country, and 3 who studied for a semester in England, a developed country. Using phenomenology as its guiding framework, transcribed interviews were analyzed and the focal phenomenon of the…

  12. Comparison of Environmental Attitudes and Experiences of Five-Year-Old Children Receiving Preschool Education in the Village and City Centre

    ERIC Educational Resources Information Center

    Durkan, Nazmi; Güngör, Hande; Fetihi, Leyla; Erol, Ahmet; Gülay Ogelman, Hülya

    2016-01-01

    The purpose of the study is to compare environmental attitudes and experiences of five-year-old children receiving preschool education in the village and city centre. The first group comprised 54 five-year-old children who received preschool education and attended kindergartens of two primary schools in the Karateke and Kocabas villages of Honaz…

  13. Conference on Complex Turbulent Flows: Comparison of Computation and Experiment, Stanford University, Stanford, CA, September 14-18, 1981, Proceedings. Volume 2 - Taxonomies, reporters' summaries, evaluation, and conclusions

    NASA Technical Reports Server (NTRS)

    Kline, S. J. (Editor); Cantwell, B. J. (Editor); Lilley, G. M.

    1982-01-01

    Computational techniques for simulating turbulent flows were explored, together with the results of experimental investigations. Particular attention was devoted to the possibility of defining a universal closure model, applicable for all turbulence situations; however, conclusions were drawn that zonal models, describing localized structures, were the most promising techniques to date. The taxonomy of turbulent flows was summarized, as were algebraic, differential, integral, and partial differential methods for numerical depiction of turbulent flows. Numerous comparisons of theoretically predicted and experimentally obtained data for wall pressure distributions, velocity profiles, turbulent kinetic energy profiles, Reynolds shear stress profiles, and flows around transonic airfoils were presented. Simplifying techniques for reducing the necessary computational time for modeling complex flowfields were surveyed, together with the industrial requirements and applications of computational fluid dynamics techniques.

  14. Spectral shapes of Ar-broadened HCl lines in the fundamental band by classical molecular dynamics simulations and comparison with experiments

    SciTech Connect

    Tran, H.; Domenech, J.-L.

    2014-08-14

    Spectral shapes of isolated lines of HCl perturbed by Ar are investigated for the first time using classical molecular dynamics simulations (CMDS). Using reliable intermolecular potentials taken from the literature, these CMDS provide the time evolution of the auto-correlation function of the dipole moment, whose Fourier-Laplace transform leads to the absorption spectrum. In order to test these calculations, room temperature spectra of various lines in the fundamental band of HCl diluted in Ar are measured, in a large pressure range, with a difference-frequency laser spectrometer. Comparisons between measured and calculated spectra show that the CMDS are able to predict the large Dicke narrowing effect on the shape of HCl lines and to satisfactorily reproduce the shapes of HCl spectra at different pressures and for various rotational quantum numbers.

  15. Effect of higher order nonlinearity, directionality and finite water depth on wave statistics: Comparison of laboratory experiments, field data and numerical simulations.

    NASA Astrophysics Data System (ADS)

    Fernández, Leandro; Onorato, Miguel; Monbaliu, Jaak; Toffoli, Alessandro

    2015-04-01

    This research is focused on the study of nonlinear evolution of irregular wave fields in water of arbitrary depth by comparing laboratory experiments, field measurements and numerical simulations. It is now well accepted that modulational instability, known as one of the main mechanisms for the formation of rogue waves, induces strong departures from Gaussian statistics and second order based statistics. However, whereas non-Gaussian properties are remarkable when wave fields follow one direction of propagation over an infinite water depth, wave statistics only weakly deviate from Gaussianity when waves spread over a range of different directions. Over finite water depth, furthermore, wave instability attenuates overall and eventually vanishes for relative water depths as low as kh = 1.36 (where k is the wavenumber of the dominant waves and h the water depth). Recent experimental results, nonetheless, seem to indicate that oblique perturbations are capable of triggering and sustaining modulational instability even if kh < 1.36. In this regard, the aim of this research is to understand whether the combined effect of directionality and finite water depth has a significant effect on wave statistics and particularly on the occurrence of extremes. For this purpose, laboratory experiments in a large wave basin, numerical experiments solving the Euler equation of motion with the Higher Order Spectral Method (HOSM) and field experiments at the Lake George experimental site (Australia) have been compared to assess the role of third order nonlinearity, and particularly modulational instability, on wave statistics. Herein, we present a comparative analysis of the statistical properties (i.e. density function of the surface elevation and its statistical moments skewness and kurtosis) between laboratory experiments, simulations and in-situ data which provides a confrontation between the numerical results and real observations in laboratory and field conditions.

  16. Monitoring the interaction of hydraulic fracturing fluid with Marcellus Shale using Sr isotopes: a comparison of laboratory experiments with field scale observations (Invited)

    NASA Astrophysics Data System (ADS)

    Wall, A. J.; Hakala, A.; Marcon, V.; Joseph, C.

    2013-12-01

    Strontium isotopes have the potential to be an effective tool for differentiating Marcellus Shale derived-fluids from other sources in surface and ground waters (Chapman et al. 2012, doi: 10.1021/es204005g). Water that is co-produced during gas extraction is likely influenced by fluid/rock interactions during hydraulic fracturing (HF) and monitoring changes in Sr isotope ratios can provide insight into reactions occurring within the shale formation. However, questions persist as to what controls the Sr isotopic composition of Marcellus Shale fluids, especially during HF. Here we compare laboratory experiments, simulating the dissolution of the Marcellus Shale during HF, with a time-series of water samples taken from a Marcellus Shale gas wells after HF has occurred. For the laboratory experiments, a core sample of Marcellus Shale from Greene County, PA was crushed and placed into a high P and T reaction vessel. Solutions were added in two different experiments: one with synthetic brine, and another using brine+HF fluid. The HF fluid was made up of components listed on fracfocus.org. Experiments were run for ~16 days at 27.5 MPa and 130oC. Aqueous samples were periodically removed for analysis and Sr isotope ratios were measured by MC-ICP-MS. Using just brine, the pH of the solution decreased from 7.6 to 5.3 after 24 hrs, then reached a steady state at ~6.1. Sr/Ca molar ratios in the fluid started at 2.3 after 24 hours and decreased to 1.8 over ~16 days. During this time only 6% of the total inorganic carbon (TIC) dissolved from the shale. The ɛSr values started at +43.2 and decreased to +42.4. In the experiment using brine+HF fluid, the pH started at 1.8 and rose slowly to a steady value of 5.6 by day 6. The Sr and Ca concentrations were higher than the brine experiment, but the Sr/Ca ratios remained lower at ~0.3 through the experiment. The increased Ca release, as well as the dissolution of over 60% of the TIC, suggests the dissolution of a carbonate mineral

  17. Experiments with needle bearings

    NASA Technical Reports Server (NTRS)

    Ferretti, Pericle

    1933-01-01

    Experiments and results are presented in testing needle bearings, especially in comparison with roller bearings. Reduction in coefficient of friction is discussed as well as experimental methods and recording devices.

  18. A comparison of on-campus first year undergraduate nursing students' experiences with face-to-face and on-line discussions.

    PubMed

    Jacobsen, Hilary E

    2006-08-01

    Only limited pedagogical use has been made of information and communications technology (ICT) in nursing education in Norway. In this study the use of ICT was linked to assignments in the first year undergraduate nursing program and included four on-line discussions. There is evidence to suggest that on-line discussions can enhance the learning environment. The students' experiences of the on-line discussions are compared to those of the students participating in traditional group discussions. The results show little difference between the two groups' opinions of the discussions' fruitfulness and the ease in which they expressed their feelings, thoughts and ideas. However, there is a marked difference between the two groups regarding their experience of how the discussions affected the amount of contact between group members outside the discussions. Possible reasons for these findings are discussed. PMID:16519969

  19. [THE AGE AND WORK EXPERIENCE DYNAMICS OF INDICES OF HEALTH OF EMPLOYEES--CRITERIA FOR COMPARISON OF OCCUPATIONAL AND NONOCCUPATIONAL RISKS].

    PubMed

    Sorokin, G A

    2016-01-01

    There are reported data of the analysis of parameters of the general morbidity (hypertension, chronic diseases, organs of respiratory and digestive system, adiposity, vertebral osteochondrosis) in dependence on age and work experience of dockers-mechanizators in seaport at various working conditions. Morbidity rate indices were calculated on results of the profound medical examination at annual periodic surveys of workers. There were analyzed ecological and ergonomic indices of working conditions, including an estimation of physiological intensity of the work. The general hygienic assessment of working conditions was executed on the basis of the measurement of rates of gains in the risk of diseases depending on age and the experience of work (an annual gain of risk). The divergence of these rates was used for the determination of occupational and nonoccupational fractions of the general morbidity in employees working in harmful conditions. PMID:27430067

  20. On the features of dislocation-obstacle interactions in thin films: direct comparison between in situ experiments and large scale computer modeling.

    SciTech Connect

    Osetskiy, Yury N; Matsukawa, Yoshitaka; Stoller, Roger E; Zinkle, Steven J

    2006-01-01

    Large-scale atomistic modelling has demonstrated that the dynamic interactions of dislocations in thin films have a number of remarkable features. A particular example is the interaction between a screw dislocation and a stacking fault tetrahedron (SFT) in Cu, which can be directly compared with in situ observations of quenched or irradiated fcc metals. If the specimen is thin, the dislocation velocity is slow, and the temperature is high enough, a segment of the original SFT can be transported towards the surface via a double cross-slip mechanism and fast glide of an edge dislocation segment formed during the interaction. The mechanisms observed in the simulations provide an explanation for the results of in situ straining experiments and the differences between bulk and thin film experiments.

  1. Comparison of Subjective Experiences and Effectiveness of First-Generation Long-Acting Injectable Antipsychotics and Risperidone Long-Acting Injectables in Patients With Schizophrenia.

    PubMed

    Chen, Wen-Yin; Lin, Shih-Ku

    2016-10-01

    We conducted a cross-sectional study to compare the subjective experiences and clinical effects of first-generation long-acting injectable (FGA-LAI) antipsychotics with those of risperidone long-acting injectables (RIS-LAIs) in 434 schizophrenia patients. Compared with the RIS-LAI group, the patients treated with FGA-LAIs had a significantly longer duration of illness and LAI treatment and were older. Our results suggest that patients treated with FGA-LAI have more satisfactory subjective experiences compared with patients treated with RIS-LAI and that both FGA-LAI and RIS-LAI treatments can prevent relapses and hospitalization. Additional longitudinal studies determining the long-term benefits of RIS-LAI are warranted. PMID:27580495

  2. [THE AGE AND WORK EXPERIENCE DYNAMICS OF INDICES OF HEALTH OF EMPLOYEES--CRITERIA FOR COMPARISON OF OCCUPATIONAL AND NONOCCUPATIONAL RISKS].

    PubMed

    Sorokin, G A

    2016-01-01

    There are reported data of the analysis of parameters of the general morbidity (hypertension, chronic diseases, organs of respiratory and digestive system, adiposity, vertebral osteochondrosis) in dependence on age and work experience of dockers-mechanizators in seaport at various working conditions. Morbidity rate indices were calculated on results of the profound medical examination at annual periodic surveys of workers. There were analyzed ecological and ergonomic indices of working conditions, including an estimation of physiological intensity of the work. The general hygienic assessment of working conditions was executed on the basis of the measurement of rates of gains in the risk of diseases depending on age and the experience of work (an annual gain of risk). The divergence of these rates was used for the determination of occupational and nonoccupational fractions of the general morbidity in employees working in harmful conditions.

  3. A comparison of theory and experiment for coupled rotor-body stability of a hingeless rotor model in hover under simulated vacuum conditions

    NASA Technical Reports Server (NTRS)

    Bousman, William G.

    1988-01-01

    Two cases were selected for correlation from an experiment that examined the aeromechanical stability of a small-scale model rotor that used tantalum rods instead of blades to simulate vacuum conditions. The first case involved body roll freedom only while the second case included body pitch and roll degrees of freedom together. Analyses from Hughes Helicopters and the U.S. Army Aeromechanics Laboratory were compared with the data and the correlations ranged from poor to good.

  4. Associations of symptoms, psychosocial function and hope with qualities of self-experience in schizophrenia: comparisons of objective and subjective indicators of health.

    PubMed

    Lysaker, Paul H; Buck, Kelly D; Hammoud, Kristin; Taylor, Amanda C; Roe, David

    2006-02-28

    While changes in self-experience have been suggested to be an important element of recovery from severe mental illness, little is known about how qualities of self-experience are linked with other indicators of health including objective measures such as symptoms profiles and subjective measures such as hope. To examine these issues the narratives of self and illness of 65 persons with schizophrenia spectrum disorder were obtained prior to entry into rehabilitation and rated using the Scale to Assess Narrative Development (STAND). STAND scores were then compared with concurrent assessments of hope assessed with the Beck Hopelessness Scale (BHS), psychosocial function using the Quality of Life Scale (QOLS) and symptom profile defined categorically using the Positive and Negative Syndrome Scale (PANSS). Results suggest that higher ratings of the STAND were associated with greater expectations of perseverance on the BHS and higher levels of psychosocial function on the QOL. Lower symptom profiles were similarly linked with higher STAND scores. Results suggest qualities of self-experience expressed within personal narratives are linked to symptom profiles and subjective assessments of health. Theoretical and clinical implications are discussed.

  5. Evolution of chevron folds by profile shape changes: comparison between multilayer deformation experiments and folds of the Bendigo-Castlemaine goldfields, Australia

    NASA Astrophysics Data System (ADS)

    Fowler, T. J.; Winsor, C. N.

    1996-06-01

    The Bendigo-Castlemaine goldfields lie within the well-known chevron-folded Ordovician turbidites of Victoria, Australia. Detailed re-examination of surface and subsurface maps indicates that there are other common fold shapes (boxfolds and flat-topped folds with subsidiary hinges) which are enclosed within chevron folded layers and are traceable into them. Plasticine multilayer experiments were performed to examine the fold profile shape evolution of chevrons and associated folds. In the experiments chevrons evolved from sinusoidal folds or boxfolds. Sinusoidal folds became chevrons mainly via hinge sharpening, while boxfolds evolved into chevrons via hinge migration and fusion of the hinges. For boxfolds, hinge migration rates controlled rates of limb steepening versus median segment (i.e., the flat top of the boxfold) length reduction during bulk shortening. Periodic slowing or "jamming" of hinge migration led to stepwise) limb-dip increases, and buckling of median segments producing analogous fold styles to those seen in the Bendigo-Castlemaine folds. Limb steepening in a boxfolded multilayer must lead to dilations spanning the median segment and/or curving of boxfold axial planes. The latter dilations experience the same shape changes as their enclosing folded layers. In nature such dilation may be represented by bedding-parallel veins which are subsequently incorporated onto chevron limbs as a result of hinge migration. Thus bedding-parallel veins which are continuous over chevron hinges and are folded in the hinge zones need not be pre-folding or early-folding.

  6. Reactive scattering of H2 from Cu(100): Comparison of dynamics calculations based on the specific reaction parameter approach to density functional theory with experiment

    NASA Astrophysics Data System (ADS)

    Sementa, L.; Wijzenbroek, M.; van Kolck, B. J.; Somers, M. F.; Al-Halabi, A.; Busnengo, H. F.; Olsen, R. A.; Kroes, G. J.; Rutkowski, M.; Thewes, C.; Kleimeier, N. F.; Zacharias, H.

    2013-01-01

    We present new experimental and theoretical results for reactive scattering of dihydrogen from Cu(100). In the new experiments, the associative desorption of H2 is studied in a velocity resolved and final rovibrational state selected manner, using time-of-flight techniques in combination with resonance-enhanced multi-photon ionization laser detection. Average desorption energies and rotational quadrupole alignment parameters were obtained in this way for a number of (v = 0, 1) rotational states, v being the vibrational quantum number. Results of quantum dynamics calculations based on a potential energy surface computed with a specific reaction parameter (SRP) density functional, which was derived earlier for dihydrogen interacting with Cu(111), are compared with the results of the new experiments and with the results of previous molecular beam experiments on sticking of H2 and on rovibrationally elastic and inelastic scattering of H2 and D2 from Cu(100). The calculations use the Born-Oppenheimer and static surface approximations. With the functional derived semi-empirically for dihydrogen + Cu(111), a chemically accurate description is obtained of the molecular beam experiments on sticking of H2 on Cu(100), and a highly accurate description is obtained of rovibrationally elastic and inelastic scattering of D2 from Cu(100) and of the orientational dependence of the reaction of (v = 1, j = 2 - 4) H2 on Cu(100). This suggests that a SRP density functional derived for H2 interacting with a specific low index face of a metal will yield accurate results for H2 reactively scattering from another low index face of the same metal, and that it may also yield accurate results for H2 interacting with a defected (e.g., stepped) surface of that same metal, in a system of catalytic interest. However, the description that was obtained of the average desorption energies, of rovibrationally elastic and inelastic scattering of H2 from Cu(100), and of the orientational dependence of

  7. Reactive scattering of H2 from Cu(100): comparison of dynamics calculations based on the specific reaction parameter approach to density functional theory with experiment.

    PubMed

    Sementa, L; Wijzenbroek, M; van Kolck, B J; Somers, M F; Al-Halabi, A; Busnengo, H F; Olsen, R A; Kroes, G J; Rutkowski, M; Thewes, C; Kleimeier, N F; Zacharias, H

    2013-01-28

    We present new experimental and theoretical results for reactive scattering of dihydrogen from Cu(100). In the new experiments, the associative desorption of H(2) is studied in a velocity resolved and final rovibrational state selected manner, using time-of-flight techniques in combination with resonance-enhanced multi-photon ionization laser detection. Average desorption energies and rotational quadrupole alignment parameters were obtained in this way for a number of (v = 0, 1) rotational states, v being the vibrational quantum number. Results of quantum dynamics calculations based on a potential energy surface computed with a specific reaction parameter (SRP) density functional, which was derived earlier for dihydrogen interacting with Cu(111), are compared with the results of the new experiments and with the results of previous molecular beam experiments on sticking of H(2) and on rovibrationally elastic and inelastic scattering of H(2) and D(2) from Cu(100). The calculations use the Born-Oppenheimer and static surface approximations. With the functional derived semi-empirically for dihydrogen + Cu(111), a chemically accurate description is obtained of the molecular beam experiments on sticking of H(2) on Cu(100), and a highly accurate description is obtained of rovibrationally elastic and inelastic scattering of D(2) from Cu(100) and of the orientational dependence of the reaction of (v = 1, j = 2 - 4) H(2) on Cu(100). This suggests that a SRP density functional derived for H(2) interacting with a specific low index face of a metal will yield accurate results for H(2) reactively scattering from another low index face of the same metal, and that it may also yield accurate results for H(2) interacting with a defected (e.g., stepped) surface of that same metal, in a system of catalytic interest. However, the description that was obtained of the average desorption energies, of rovibrationally elastic and inelastic scattering of H(2) from Cu(100), and of the

  8. Experiments for a systematic comparison between stable-isotope-(deuterium) labeling and radio-((14)C) labeling for the elucidation of the in vitro metabolic pattern of pharmaceutical drugs.

    PubMed

    Grunwald, Helge; Hargreaves, Patrick; Gebhardt, Klaus; Klauer, Dominique; Serafyn, Arnaud; Schmitt-Hoffmann, Anne; Schleimer, Michael; Schlotterbeck, Goetz; Wind, Mathias

    2013-11-01

    A systematic comparison between two labeling approaches for the investigation of the in vitro metabolic pattern of pharmaceutical drugs was performed by examining the use of (i) radiolabeled drugs analyzed with LC-MS-offline radiodetection and (ii) stable-isotope labeled drugs, used in a defined mixture with the unlabeled drug and analyzed by LC-MS with recognition of the specific isotopic pattern. (14)C was used for the radioisotope-approach and deuterium for the stable-isotope approach. Olanzapine, diclofenac and ketoconazole were chosen as model drugs, as they are commercially available in their non-, radio- and stable-isotope labeled forms. For all three model drugs, liver microsome- and hepatocyte-incubations (both from rat) were performed with various concentrations and incubation times for both, the radio- and the stable-isotope approaches. The metabolic pattern, including structure elucidation of all detected metabolites, was performed independently for all individual compounds and incubations. Subsequently, the metabolic patterns of the radio-, and the stable-isotope approaches were compared. In conclusion, all metabolites found with the radioisotope approach could also be found with the stable-isotope approach. Although the stable-isotope approach does not provide a quantitative result, it can be considered to be a highly suited analytical alternative for early in vitro metabolism investigations, especially when radiolabeled drug analogues are not yet available and quantitative results are not yet necessary.

  9. Hydration of nucleic acid fragments: comparison of theory and experiment for high-resolution crystal structures of RNA, DNA, and DNA-drug complexes.

    PubMed

    Hummer, G; García, A E; Soumpasis, D M

    1995-05-01

    A computationally efficient method to describe the organization of water around solvated biomolecules is presented. It is based on a statistical mechanical expression for the water-density distribution in terms of particle correlation functions. The method is applied to analyze the hydration of small nucleic acid molecules in the crystal environment, for which high-resolution x-ray crystal structures have been reported. Results for RNA [r(ApU).r(ApU)] and DNA [d(CpG).d(CpG) in Z form and with parallel strand orientation] and for DNA-drug complexes [d(CpG).d(CpG) with the drug proflavine intercalated] are described. A detailed comparison of theoretical and experimental data shows positional agreement for the experimentally observed water sites. The presented method can be used for refinement of the water structure in x-ray crystallography, hydration analysis of nuclear magnetic resonance structures, and theoretical modeling of biological macromolecules such as molecular docking studies. The speed of the computations allows hydration analyses of molecules of almost arbitrary size (tRNA, protein-nucleic acid complexes, etc.) in the crystal environment and in aqueous solution.

  10. The Clinical and Pathological Presentation of Thyroid Nodules in Children and the Comparison with Adult Population: Experience of a Single Institution

    PubMed Central

    Solymosi, Tamas; Lukacs Toth, Gyula; Budai, Laszlo; Gal, Istvan

    2016-01-01

    The clinical and pathological presentation of thyroid nodules among younger and adult patients was compared in an iodine-deficient (ID) region. Data of 3,010 consecutive patients younger than 20 years and 3,010 patients older than 20 years were compared. The proportion of nodular goiters (22.8% versus 39.3%), the ratio of surgically treated nodules (33.2% versus 15.2%), and the proportion of malignant nodules (4.3% versus 2.1%) among diseased patients differed significantly between the two groups (younger versus adult). Nine papillary and 1 medullary carcinoma were found among children, while 15 papillary, 2 follicular, 1 insular, 1 anaplastic, and 1 medullary carcinomas occurred among adults. The ratio of follicular adenoma to hyperplastic nodules (3 : 1 to 1 : 1.67), the proportion of follicular variant (77.8% versus 26.7%), T4 tumors (77.8% versus 33.3%), and tumors with lymph node metastasis (88.9% versus 66.7%) were significantly higher among younger papillary carcinoma patients. No malignancies occurred among spongiform and central type cysts. Similarly to iodine-sufficient regions, more nodules are malignant and carcinomas have a clinically more aggressive presentation in children in comparison with adult patients in ID. Taking the significantly greater proportion of adenomas and the lack of follicular carcinoma into account, a conservative approach has to be considered in follicular tumors among children. PMID:27087807

  11. Thermophilic anaerobic co-digestion of cattle manure with agro-wastes and energy crops: comparison of pilot and full scale experiences.

    PubMed

    Cavinato, C; Fatone, F; Bolzonella, D; Pavan, P

    2010-01-01

    The paper deals with the benefits coming from the application of a proper process temperature (55 degrees C) instead of a 'reduced' thermophilic range (47 degrees C), that is often applied in European anaerobic co-digestion plants. The experimental work has pointed out that biogas production improve from 0.45 to 0.62 m(3)/kg VS operating at proper thermophilic conditions. Moreover, also methane content was higher: from 52% to 61%. A general improvement in digester behaviour was clear also considering the stability parameters comparison (pH, ammonia, VFA content). The second part of the study takes into account the economic aspects related to the capital cost of anaerobic digestion treatment with a 1 MW co-generation unit fro heat and power production (CHP). Moreover, the economic balance was also carried out considering the anaerobic supernatants treatment for nitrogen removal. The simulation showed how a pay-back-time of 2.5 yr and between 3 and 5 yr respectively could be determined when the two options of anaerobic digestion only and together with the application of a nitrogen removal process were considered. PMID:19747821

  12. Tick-borne encephalitis and Lyme borreliosis: comparison of habitat risk assessments using satellite data (an experience from the Central Bohemian region of the Czech Republic).

    PubMed

    Daniel, M; Kolár, J; Zeman, P; Pavelka, K; Sádlo, J

    1999-02-01

    The vegetation types have been used as the indicators of an ecosystem suitable for high incidence of Ixodes ricinus ticks and their hosts, for the circulation of tick-borne diseases pathogens and, accordingly, for the existence of natural foci of these infections, namely tick-borne encephalitis (TBE) and Lyme borreliosis (LB). The method of remote sensing offers a suitable solution to this problem. We attempted to prepare the habitat risk assessment maps on the territory (11,500 km2) of Central Bohemia (Czech Republic) using Landsat 5 TM imagery. Nine forest classes have been recognized in the satellite data and further identified in a field checking botanical survey. Beside the conclusions dealing with the importance of different plant types for I. ricinus occurrence, also the epidemiological TBE and LB maps based on human cases contracted in the territory under study were exploited for the evaluation of particular forest classes significance, and for the comparison of results achieved. Apart from a general pattern of risk gradation from coniferous to deciduous wood types, both TBE and LB data suggest a specific position of the heterogeneous deciduous wood class (including mainly young deciduous stands and stand ecotones with highly heterogeneous structure). Epidemiological significance of the other particular forest classes was assessed by the degrees of positive class-to-risk associations (see Table 1 and 2).

  13. Chemistry Experiments

    NASA Technical Reports Server (NTRS)

    Brasseur, Guy; Remsberg, Ellis; Purcell, Patrick; Bhatt, Praful; Sage, Karen H.; Brown, Donald E.; Scott, Courtney J.; Ko, Malcolm K. W.; Tie, Xue-Xi; Huang, Theresa

    1999-01-01

    The purpose of the chemistry component of the model comparison is to assess to what extent differences in the formulation of chemical processes explain the variance between model results. Observed concentrations of chemical compounds are used to estimate to what degree the various models represent realistic situations. For readability, the materials for the chemistry experiment are reported in three separate sections. This section discussed the data used to evaluate the models in their simulation of the source gases and the Nitrogen compounds (NO(y)) and Chlorine compounds (Cl(y)) species.

  14. Breakthrough of two pesticides into tile drain and shallow groundwater: comparison of tile drain reaction and soil profiles within a field scale irrigation experiment

    NASA Astrophysics Data System (ADS)

    Klaus, Julian; Zehe, Erwin; Elsner, Martin; Palm, Juliane; Schneider, Dorothee; Schröder, Boris; Steinbeiss, Sibylle; West, Stephanie

    2010-05-01

    Preferential flow in macropores is a key process which strongly affects infiltration and may cause rapid transport of pesticides into depths of 80 to 150 cm. At these depths they experience a much slower degradation, may leach into shallow groundwater or enter a tile-drain and are transported into surface water bodies. Therefore, preferential transport might be an environmental problem, if the topsoil is bypassed, which has been originally thought to act as a filter to protect the subsoil and shallow groundwater. To investigate the behaviour of two pesticides with different chemical characteristics and to compare their transport behaviour in soil and into the tile drain an irrigation experiment was performed on a 400 m² field site. The experimental plot is located in the Weiherbach valley, south-west Germany, which basic geology consists of Loess and Keuper layers, the soil at the test site is a gleyic Colluvisol. The distance of the irrigation site to the Weiherbach brook is approximately 12 m, the field is drained with a tile-drain in about 1.2 m depth and shows discharge over the entire year. Three hours before the irrigation started, the farmer applied a pesticide solution consisting of Isoproturon (80 g) and Flufenacet (20 g) (IPU and FLU) according to conventional agricultural practice on the field plot. The irrigation took place in three time blocks (80 min, 60 min, 80 min) with in total 33.6 mm of precipitation. During the first block 1600 g of Bromide were mixed in the irrigation water. The drainage outlet was instrumented with a pressure probe. About 50 water samples ware taken during the experimental day, and several samples more the days after the experiment. They were analysed for the pesticides, bromide and water isotopes. In the two days after the experiment three soil profiles were excavated and soil samples were taken on a 10x10 cm² scheme. One week after the experiment two additional profiles were excavated. The soil was analysed for IPU, FLU

  15. Simulation studies of the Cl{sup -}+ CH{sub 3}I S{sub N}2 nucleophilic substitution reaction: Comparison with ion imaging experiments

    SciTech Connect

    Zhang Jiaxu; Lourderaj, Upakarasamy; Sun Rui; Hase, William L.; Mikosch, Jochen; Wester, Roland

    2013-03-21

    In the previous work of Mikosch et al.[Science 319, 183 (2008)], ion imaging experiments were used to study the Cl{sup -}+ CH{sub 3}I {yields} ClCH{sub 3}+ I{sup -} reaction at collision energies E{sub rel} of 0.39, 0.76, 1.07, and 1.9 eV. For the work reported here MP2(fc)/ECP/d direct dynamics simulations were performed to obtain an atomistic understanding of the experiments. There is good agreement with the experimental product energy and scattering angle distributions for the highest three E{sub rel}, and at these energies 80% or more of the reaction is direct, primarily occurring by a rebound mechanism with backward scattering. At 0.76 eV there is a small indirect component, with isotropic scattering, involving formation of the pre- and post-reaction complexes. All of the reaction is direct at 1.07 eV. Increasing E{sub rel} to 1.9 eV opens up a new indirect pathway, the roundabout mechanism. The product energy is primarily partitioned into relative translation for the direct reactions, but to CH{sub 3}Cl internal energy for the indirect reactions. The roundabout mechanism transfers substantial energy to CH{sub 3}Cl rotation. At E{sub rel}= 0.39 eV both the experimental product energy partitioning and scattering are statistical, suggesting the reaction is primarily indirect with formation of the pre- and post-reaction complexes. However, neither MP2 nor BhandH/ECP/d simulations agree with experiment and, instead, give reaction dominated by direct processes as found for the higher collision energies. Decreasing the simulation E{sub rel} to 0.20 eV results in product energy partitioning and scattering which agree with the 0.39 eV experiment. The sharp transition from a dominant direct to indirect reaction as E{sub rel} is lowered from 0.39 to 0.20 eV is striking. The lack of agreement between the simulations and experiment for E{sub rel}= 0.39 eV may result from a distribution of collision energies in the experiment and/or a shortcoming in both the MP2 and Bhand

  16. Consumer preferences for food labels on tomatoes in Germany - A comparison of a quasi-experiment and two stated preference approaches.

    PubMed

    Meyerding, Stephan G H

    2016-08-01

    In many studies, consumer preferences are determined by using direct surveys. For this method social desirability is problematic. This leads to the effect that participants answer in a way that they perceive as desired by society. This leads to the stated importance of certain features in these studies not being reflected in real purchasing decisions. Therefore, the aim of the study is to compare consumer preferences measured by a quasi-experiment to those quantified by direct questions. Another objective is to quantify the part-worth utilities of product characteristics such as origin, price and food labels. Part-worth utilities are estimated on an interval scale with an arbitrary origin and are a measure for preferences. The real purchasing situation was simulated in a quasi-experiment using a choice-based conjoint analysis. The part-worth utilities were then compared with the results of a conventional preference assessment (Likert scale). For this purpose, 645 consumers from all over Germany were surveyed in 2014. The participants were on average 44 years old and 63% were women. The results of the conjoint analysis report the highest part-worth utility (2.853) for the lowest price (1.49€), followed by the characteristic "grown locally" (2.157). For the labels, the German organic label shows the highest part-worth utility (0.785) followed by Fairtrade/"A heart for the producer" (0.200). It is noticeable that the carbon footprint labels have negative part-worth utilities compared to tomatoes without a label (-0.130 with CO2 indication, -0.186 without CO2 indication). The price is ranked 12th in the importance of the characteristics of purchasing tomatoes in the survey with a Likert scale, whereas it is first in the evaluation of the quasi-experiment (conjoint analysis), which supports the assumption of a social desirability bias. PMID:27037221

  17. Consumer preferences for food labels on tomatoes in Germany - A comparison of a quasi-experiment and two stated preference approaches.

    PubMed

    Meyerding, Stephan G H

    2016-08-01

    In many studies, consumer preferences are determined by using direct surveys. For this method social desirability is problematic. This leads to the effect that participants answer in a way that they perceive as desired by society. This leads to the stated importance of certain features in these studies not being reflected in real purchasing decisions. Therefore, the aim of the study is to compare consumer preferences measured by a quasi-experiment to those quantified by direct questions. Another objective is to quantify the part-worth utilities of product characteristics such as origin, price and food labels. Part-worth utilities are estimated on an interval scale with an arbitrary origin and are a measure for preferences. The real purchasing situation was simulated in a quasi-experiment using a choice-based conjoint analysis. The part-worth utilities were then compared with the results of a conventional preference assessment (Likert scale). For this purpose, 645 consumers from all over Germany were surveyed in 2014. The participants were on average 44 years old and 63% were women. The results of the conjoint analysis report the highest part-worth utility (2.853) for the lowest price (1.49€), followed by the characteristic "grown locally" (2.157). For the labels, the German organic label shows the highest part-worth utility (0.785) followed by Fairtrade/"A heart for the producer" (0.200). It is noticeable that the carbon footprint labels have negative part-worth utilities compared to tomatoes without a label (-0.130 with CO2 indication, -0.186 without CO2 indication). The price is ranked 12th in the importance of the characteristics of purchasing tomatoes in the survey with a Likert scale, whereas it is first in the evaluation of the quasi-experiment (conjoint analysis), which supports the assumption of a social desirability bias.

  18. Impact of Dynamic Specimen Shape Evolution on the Atom Probe Tomography Results of Doped Epitaxial Oxide Multilayers: Comparison of Experiment and Simulation

    SciTech Connect

    Madaan, Nitesh; Bao, Jie; Nandasiri, Manjula I.; Xu, Zhijie; Thevuthasan, Suntharampillai; Devaraj, Arun

    2015-08-31

    The experimental atom probe tomography results from two different specimen orientations (top-down and side-ways) of a high oxygen ion conducting Samaria-doped-ceria/Scandia-stabilized-zirconia multilayer thin film solid oxide fuel cell electrolyte was correlated with level-set method based field evaporation simulations for the same specimen orientations. This experiment-theory correlation explains the dynamic specimen shape evolution and ion trajectory aberrations that can induce density artifacts in final reconstruction leading to inaccurate estimation of interfacial intermixing. This study highlights the need and importance of correlating experimental results with field evaporation simulations when using atom probe tomography for studying oxide heterostructure interfaces.

  19. Organic matter production response to CO2 increase in open subarctic plankton communities: Comparison of six microcosm experiments under iron-limited and -enriched bloom conditions

    NASA Astrophysics Data System (ADS)

    Yoshimura, Takeshi; Sugie, Koji; Endo, Hisashi; Suzuki, Koji; Nishioka, Jun; Ono, Tsuneo

    2014-12-01

    Increase in seawater pCO2 and the corresponding decrease in pH caused by the increasing atmospheric CO2 concentration (i.e., ocean acidification) may affect organic matter production by phytoplankton communities. Organic matter production forms the basis of marine food webs and plays a crucial role in oceanic CO2 uptake through the biological carbon pump, and hence will potentially affect future marine ecosystem dynamics. However, responses of organic matter production in open ocean plankton ecosystems to CO2 increase have not been fully examined. We conducted on-deck microcosm experiments using high nutrient, low chlorophyll (HNLC) waters in the western subarctic Pacific and oceanic Bering Sea basin in summer 2008 and 2009, respectively, to examine the impacts of elevated CO2 on particulate and dissolved organic matter (i.e., POM and DOM, respectively) production. Iron deficient natural plankton communities were incubated for 7-14 days under multiple CO2 levels with and without iron enrichments (hereafter +Fe and -Fe treatments, respectively). By combining with our previous experiments at two sites, we created a comprehensive dataset on responses of organic matter production to CO2 increase during macronutrient replete conditions in HNLC waters. Significant differences in net particulate organic carbon production among CO2 treatments were observed only in the -Fe treatments, whereas that in net dissolved organic carbon production were mainly observed in the +Fe treatments, suggesting that CO2 may affect different processes depending on the Fe nutritional status. However, impacts of CO2 were not consistent among experiments and were much smaller than the consistent positive effects of Fe enrichment. In contrast, no significant differences among the CO2 treatments were observed for organic carbon partitioning into POM and DOM, and carbon to nitrogen ratio of net produced POM. We conclude that CO2 does not play a primary role, but could have secondary effects on

  20. An assessment of the long-term drift in SBUV total ozone data, based on comparison with the Dobson network. [Solar Backscatter UltraViolet experiment

    NASA Technical Reports Server (NTRS)

    Fleig, Albert J.; Bhartia, Pawan K.; Silberstein, David S.

    1986-01-01

    Six years of total ozone data derived from the Nimbus 7 Solar Backscatter Ultraviolet (SBUV) experiment are compared with results from 41 Dobson stations to determine year-to-year changes in addition to the monthly bias change for individual stations and for the network. The SBUV measurements are found to drift against the Dobson stations with a linear trend of .38 + or - .13 percent/yr. The cause of the drift could not be separated between residual uncorrected drift in the SBUV instrument, limited sensitivity of the SBUV to increases in tropospheric ozone, and the effect of local increases in pollution level on individual Dobson stations.

  1. Long repetition time experiments for measurement of concentrations in systems with chemical exchange and undergoing temporal variation-comparison of methods with and without correction for saturation

    NASA Astrophysics Data System (ADS)

    Galbán, Craig J.; Spencer, Richard G. S.

    2003-02-01

    The purpose of this paper is to compare two methods for quantifying metabolite concentrations using the one-pulse experiment for a sample undergoing chemical exchange and subject to an intervention or other temporal variation. The methods, LATR-C (Long Acquisition TR (interpulse delay); Corrected for partial saturation) and LATR-NC (Long Acquisition TR; Not Corrected), are compared in terms of signal-to-noise ratio, SNR, per unit time and quantitation errors. Parameters relevant to the isolated perfused rat heart are used as a specific application, although the results are general. We assume throughout that spin-lattice relaxation times, T1, do not change. For a given flip angle, θ, TR's are calculated which result in maximal SNR per unit time under 10%, 5%, and 1% constraints on quantitation errors. Additional simulations were performed to demonstrate explicitly the dependence of the quantitation errors on TR for a fixed θ. We find (i) if the allowed error is large, and when both metabolite concentrations and rate constants vary, LATR-C permits use of shorter TR, and hence yields greater SNR per unit time, than LATR-NC; (ii) for small allowed error, the two methods give similar TR's and SNR per unit time, so that the simpler LATR-NC experiment may be preferred; (iii) large values of θ result in similar constrained TR's and hence SNR per unit time for the two methods; (iv) the ratio of concentrations of metabolites with similar T1 exhibit similar errors for the two methods.

  2. Food allergy knowledge, perception of food allergy labeling, and level of dietary practice: A comparison between children with and without food allergy experience

    PubMed Central

    Choi, Yongmi; Ju, Seyoung

    2015-01-01

    BACKGROUND/OBJECTIVES The prevalence of food allergies in Korean children aged 6 to 12 years increased from 10.9% in 1995 to 12.6% in 2012 according to nationwide population studies. Treatment for food allergies is avoidance of allergenic-related foods and epinephrine auto-injector (EPI) for accidental allergic reactions. This study compared knowledge and perception of food allergy labeling and dietary practices of students. SUBJECTS/METHODS The study was conducted with the fourth to sixth grade students from an elementary school in Yongin. A total of 437 response rate (95%) questionnaires were collected and statistically analyzed. RESULTS The prevalence of food allergy among respondents was 19.7%, and the most common food allergy-related symptoms were urticaria, followed by itching, vomiting and nausea. Food allergens, other than 12 statutory food allergens, included cheese, cucumber, kiwi, melon, clam, green tea, walnut, grape, apricot and pineapple. Children with and without food allergy experience had a similar level of knowledge on food allergies. Children with food allergy experience thought that food allergy-related labeling on school menus was not clear or informative. CONCLUSION To understand food allergies and prevent allergic reactions to school foodservice among children, schools must provide more concrete and customized food allergy education. PMID:25671074

  3. A comparison between Nimbus 5 THIR and ITPR temperatures and derived winds with rawinsonde data obtained in the AVE 2 experiment

    NASA Technical Reports Server (NTRS)

    Arnold, J. E.; Scoggins, J. R.; Fuelberg, H. E.

    1976-01-01

    During the period of May 11 and 12, 1974, NASA conducted its second Atmospheric Variability Experiment (AVE II) over the eastern United States. In this time interval, two Nimbus 5 orbits crossed the AVE II area, providing a series of ITPR soundings as well as THIR data. Horizontal temperature mapping of the AVE II cloud field is examined using two grid print map scales. Implied cloud top heights are compared with maximum radar-echo top reports. In addition, shelter temperatures in areas of clear sky are compared with the surface temperatures as determined from 11.5 micrometer radiometer data of the THIR experiment. The ITPR sounding accuracy is evaluated using interpolated radiosonde temperatures at times nearly coincident with the ITPR soundings. It was found that mean differences between the two data sets were as small as 1.3 C near 500 mb and as large as 2.9 C near the tropopause. The differences between ITPR and radiosonde temperatures at constant pressure levels were sufficient to induce significant differences in the horizontal temperature gradient. Cross sections of geostrophic wind along the orbital tracks were developed using a thermal wind buildup based on the ITPR temperature data and the radiosonde temperature data. Differences between the radiosonde and ITPR geostrophic winds could be explained on the basis of differences in the ITPR and radiosonde temperature gradients.

  4. Monte Carlo transport model comparison with 1A GeV accelerated iron experiment: heavy-ion shielding evaluation of NASA space flight-crew foodstuff.

    PubMed

    Stephens, D L; Townsend, L W; Miller, J; Zeitlin, C; Heilbronn, L

    2002-01-01

    Deep-space manned flight as a reality depends on a viable solution to the radiation problem. Both acute and chronic radiation health threats are known to exist, with solar particle events as an example of the former and galactic cosmic rays (GCR) of the latter. In this experiment Iron ions of 1A GeV are used to simulate GCR and to determine the secondary radiation field created as the GCR-like particles interact with a thick target. A NASA prepared food pantry locker was subjected to the iron beam and the secondary fluence recorded. A modified version of the Monte Carlo heavy ion transport code developed by Zeitlin at LBNL is compared with experimental fluence. The foodstuff is modeled as mixed nuts as defined by the 71st edition of the Chemical Rubber Company (CRC) Handbook of Physics and Chemistry. The results indicate a good agreement between the experimental data and the model. The agreement between model and experiment is determined using a linear fit to ordered pairs of data. The intercept is forced to zero. The slope fit is 0.825 and the R2 value is 0.429 over the resolved fluence region. The removal of an outlier, Z=14, gives values of 0.888 and 0.705 for slope and R2 respectively. PMID:12539754

  5. Monte Carlo transport model comparison with 1A GeV accelerated iron experiment: heavy-ion shielding evaluation of NASA space flight-crew foodstuff

    NASA Technical Reports Server (NTRS)

    Stephens, D. L. Jr; Townsend, L. W.; Miller, J.; Zeitlin, C.; Heilbronn, L.

    2002-01-01

    Deep-space manned flight as a reality depends on a viable solution to the radiation problem. Both acute and chronic radiation health threats are known to exist, with solar particle events as an example of the former and galactic cosmic rays (GCR) of the latter. In this experiment Iron ions of 1A GeV are used to simulate GCR and to determine the secondary radiation field created as the GCR-like particles interact with a thick target. A NASA prepared food pantry locker was subjected to the iron beam and the secondary fluence recorded. A modified version of the Monte Carlo heavy ion transport code developed by Zeitlin at LBNL is compared with experimental fluence. The foodstuff is modeled as mixed nuts as defined by the 71st edition of the Chemical Rubber Company (CRC) Handbook of Physics and Chemistry. The results indicate a good agreement between the experimental data and the model. The agreement between model and experiment is determined using a linear fit to ordered pairs of data. The intercept is forced to zero. The slope fit is 0.825 and the R2 value is 0.429 over the resolved fluence region. The removal of an outlier, Z=14, gives values of 0.888 and 0.705 for slope and R2 respectively. c2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.

  6. Monte Carlo transport model comparison with 1A GeV accelerated iron experiment: heavy-ion shielding evaluation of NASA space flight-crew foodstuff

    NASA Astrophysics Data System (ADS)

    Stephens, D. L.; Townsend, L. W.; Miller, J.; Zeitlin, C.; Heilbronn, L.

    Deep-space manned flight as a reality depends on a viable solution to the radiation problem. Both acute and chronic radiation health threats are known to exist, with solar particle events as an example of the former and galactic cosmic rays (GCR) of the latter. In this experiment Iron ions of 1A GeV are used to simulate GCR and to determine the secondary radiation field created as the GCR-like particles interact with a thick target. A NASA prepared food pantry locker was subjected to the iron beam and the secondary fluence recorded. A modified version of the Monte Carlo heavy ion transport code developed by Zeitlin at LBNL is compared with experimental fluence. The foodstuff is modeled as mixed nuts as defined by the 71 st edition of the Chemical Rubber Company (CRC) Handbook of Physics and Chemistry. The results indicate a good agreement between the experimental data and the model. The agreement between model and experiment is determined using a linear fit to ordered pairs of data. The intercept is forced to zero. The slope fit is 0.825 and the R 2 value is 0.429 over the resolved fluence region. The removal of an outlier, Z=14, gives values of 0.888 and 0.705 for slope and R 2 respectively.

  7. Pollutant dispersion in a large indoor space: Part 2 -Computational Fluid Dynamics (CFD) predictions and comparison with ascale model experiment for isothermal flow

    SciTech Connect

    Finlayson, Elizabeth U.; Gadgil, Ashok J.; Thatcher, Tracy L.; Sextro, Richard G.

    2002-10-01

    This paper reports on an investigation of the adequacy of Computational fluid dynamics (CFD), using a standard Reynolds Averaged Navier Stokes (RANS) model, for predicting dispersion of neutrally buoyant gas in a large indoor space. We used CFD to predict pollutant (dye) concentration profiles in a water filled scale model of an atrium with a continuous pollutant source. Predictions from the RANS formulation are comparable to an ensemble average of independent identical experiments. Model results were compared to pollutant concentration data in a horizontal plane from experiments in a scale model atrium. Predictions were made for steady-state (fully developed) and transient (developing) pollutant concentrations. Agreement between CFD predictions and ensemble averaged experimental measurements is quantified using the ratios of CFD-predicted and experimentally measured dye concentration at a large number of points in the measurement plane. Agreement is considered good if these ratios fall between 0.5 and 2.0 at all points in the plane. The standard k-epsilon two equation turbulence model obtains this level of agreement and predicts pollutant arrival time to the measurement plane within a few seconds. These results suggest that this modeling approach is adequate for predicting isothermal pollutant transport in a large room with simple geometry.

  8. A comparison of theory and experiment for coupled rotor body stability of a bearingless rotor model in hover and forward flight

    NASA Technical Reports Server (NTRS)

    Mirick, Paul H.

    1988-01-01

    Seven cases were selected for correlation from a 1/5.86 Froude-scale experiment that examined several rotor designs which were being considered for full-scale flight testing as part of the Bearingless Main Rotor (BMR) program. The model rotor hub used in these tests consisted of back-to-back C-beams as flexbeam elements with a torque tube for pitch control. The first four cases selected from the experiment were hover tests which examined the effects on rotor stability of variations in hub-to-flexbeam coning, hub-to-flexbeam pitch, flexbeam-to-blade coning, and flexbeam-to-blade pitch. The final three cases were selected from the forward flight tests of optimum rotor configuration as defined during the hover test. The selected cases examined the effects of variations in forward speed, rotor speed, and shaft angle. Analytical results from Bell Helicopter Textron, Boeing Vertol, Sikorsky Aircraft, and the U.S. Army Aeromechanics Laboratory were compared with the data and the correlations ranged from poor-to-fair to fair-to-good.

  9. A direct sensitivity comparison between flow-modulated comprehensive 2D and 1D GC in untargeted and targeted MS-based experiments.

    PubMed

    Tranchida, Peter Q; Franchina, Flavio A; Zoccali, Mariosimone; Bonaccorsi, Ivana; Cacciola, Francesco; Mondello, Luigi

    2013-09-01

    The present contribution is focused on the measurement of the analytical sensitivity attained in untargeted/targeted MS/MS experiments, performed using flow-modulator comprehensive 2D and 1D GC. The comprehensive 2D experiment was performed by diverting part of the high flow (circa 80%) to flush the accumulation loop (about 28 mL/min) to waste, to reduce the gas flow entering the ion source. 1D analyses were performed through: (i) unmodulated and (ii) single column applications. An equivalent temperature program was applied in the modulated and unmodulated analyses, while a faster one was employed in the single column one. In all application types, the (same) triple quadrupole instrument was operated in the full-scan and multiple reaction monitoring modes. A genuine sweet orange oil and the same sample spiked with 20 phytosanitary compounds were employed to reach the research objective. The results highlight the problems related to the flow modulation-MS combination. Specifically, it was found that sensitivity was on average three to four times higher in unmodulated and optimized single-column applications. PMID:23868497

  10. Monte Carlo transport model comparison with 1A GeV accelerated iron experiment: heavy-ion shielding evaluation of NASA space flight-crew foodstuff.

    PubMed

    Stephens, D L; Townsend, L W; Miller, J; Zeitlin, C; Heilbronn, L

    2002-01-01

    Deep-space manned flight as a reality depends on a viable solution to the radiation problem. Both acute and chronic radiation health threats are known to exist, with solar particle events as an example of the former and galactic cosmic rays (GCR) of the latter. In this experiment Iron ions of 1A GeV are used to simulate GCR and to determine the secondary radiation field created as the GCR-like particles interact with a thick target. A NASA prepared food pantry locker was subjected to the iron beam and the secondary fluence recorded. A modified version of the Monte Carlo heavy ion transport code developed by Zeitlin at LBNL is compared with experimental fluence. The foodstuff is modeled as mixed nuts as defined by the 71st edition of the Chemical Rubber Company (CRC) Handbook of Physics and Chemistry. The results indicate a good agreement between the experimental data and the model. The agreement between model and experiment is determined using a linear fit to ordered pairs of data. The intercept is forced to zero. The slope fit is 0.825 and the R2 value is 0.429 over the resolved fluence region. The removal of an outlier, Z=14, gives values of 0.888 and 0.705 for slope and R2 respectively.

  11. Polarization-dependent force driving the Eg mode in bismuth under optical excitation: comparison of first-principles theory with ultra-fast x-ray experiments

    NASA Astrophysics Data System (ADS)

    Fahy, Stephen; Murray, Eamonn

    2015-03-01

    Using first principles electronic structure methods, we calculate the induced force on the Eg (zone centre transverse optical) phonon mode in bismuth immediately after absorption of a ultrafast pulse of polarized light. To compare the results with recent ultra-fast, time-resolved x-ray diffraction experiments, we include the decay of the force due to carrier scattering, as measured in optical Raman scattering experiments, and simulate the optical absorption process, depth-dependent atomic driving forces, and x-ray diffraction in the experimental geometry. We find excellent agreement between the theoretical predictions and the observed oscillations of the x-ray diffraction signal, indicating that first-principles theory of optical absorption is well suited to the calculation of initial atomic driving forces in photo-excited materials following ultrafast excitation. This work is supported by Science Foundation Ireland (Grant No. 12/IA/1601) and EU Commission under the Marie Curie Incoming International Fellowships (Grant No. PIIF-GA-2012-329695).

  12. Phosphorylation effect on the GSSS peptide conformation in water: Infrared, vibrational circular dichroism, and circular dichroism experiments and comparisons with molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Lee, Kyung-Koo; Joo, Cheonik; Yang, Seongeun; Han, Hogyu; Cho, Minhaeng

    2007-06-01

    The phosphorylation effect on the small peptide conformation in water has not been clearly understood yet, despite the widely acknowledged notion that control of protein activity by phosphorylation works mainly by inducing conformational change. To elucidate the detailed mechanism, we performed infrared (IR) absorption and vibrational and electronic circular dichroism studies of both unphosphorylated and phosphorylated tetrapeptides, GSSS 1 and GSSpS 2. The solution structure of the tetrapeptide is found to be little dependent on the presence of the neutral or negatively charged phosphoryl group, and to be a mixture of extended structures including polyproline II (PII) and β-sheet conformations. The additional band at 1598cm-1 in the amide I IR spectrum of the phosphorylated peptide GSSpS at neutral pD appears to be clear spectroscopic evidence for direct intramolecular hydrogen-bonding interaction between the side chain dianionic phosphoryl group and the backbone amide proton. On the basis of amide I IR band analyses, the authors found that the probability of finding the phosphoryl group strongly H bonded to the backbone proton in GSSpS is about 43% at pD 7.0 and 37°C. Such a H-bonding interaction in GSSpS has the biological standard enthalpy and entropy of -15.1kJ /mol and -51.2J/Kmol, respectively. Comparisons between the experimentally measured IR and VCD spectra and the numerically simulated ones suggested that the currently available force field parameters need to be properly modified. The results in this paper may shed light on an unknown mechanism of controlling the peptide conformation by phosphorylation.

  13. Initiation and propagation of complex 3D networks of cracks in heterogeneous quasi-brittle materials: Direct comparison between in situ testing-microCT experiments and phase field simulations

    NASA Astrophysics Data System (ADS)

    Nguyen, T. T.; Yvonnet, J.; Bornert, M.; Chateau, C.

    2016-10-01

    We provide the first direct comparisons, to our knowledge, of complex 3D micro cracking initiation and propagation in heterogeneous quasi-brittle materials modelled by the phase field numerical method and observed in X-ray microtomography images recorded during in situ mechanical testing. Some material parameters of the damage model, including the process zone (internal) length, are identified by an inverse approach combining experimental data and 3D simulations. A new technique is developed to study the micro cracking at a finer scale by prescribing the local displacements measured by digital volume correlation over the boundary of a small sub-volume inside the sample during the numerical simulations. The comparisons, performed on several samples of lightweight plaster and concrete, show a remarkable quantitative agreement between the 3D crack morphology obtained by the model and by the experiments, without any a priori knowledge about the location of the initiation of the cracks in the numerical model. The results indicate that the crack paths can be predicted in a fully deterministic way in spite of the highly random geometry of the microstructure and the brittle nature of its constituents.

  14. Comparison of Predictive Factors for Postoperative Incontinence of Holmium Laser Enucleation of the Prostate by the Surgeons’ Experience During Learning Curve

    PubMed Central

    Tanaka, Kazushi; Yamamichi, Fukashi; Chiba, Koji; Fujisawa, Masato

    2016-01-01

    Purpose: To detect predictive factors for postoperative incontinence following holmium laser enucleation of the prostate (HoLEP) according to surgeon experience (beginner or experienced) and preoperative clinical data. Methods: Of 224 patients, a total of 203 with available data on incontinence were investigated. The potential predictive factors for post-HoLEP incontinence included clinical factors, such as patient age, and preoperative urodynamic study results, including detrusor overactivity (DO). We also classified the surgeons performing the procedure according to their HoLEP experience: beginner (<21 cases) and experienced (≥21 cases). Results: Our statistical data showed DO was a significant predictive factor at the super-short period (the next day of catheter removal: odds ratio [OR], 3.375; P=0.000). Additionally, patient age, surgeon mentorship (inverse correlation), and prostate volume were significant predictive factors at the 1-month interval after HoLEP (OR, 1.072; P=0.004; OR, 0.251; P=0.002; and OR, 1.008; P=0.049, respectively). With regards to surgeon experience, DO and preoperative International Prostate Symptom Score (inverse) at the super-short period, and patient age and mentorship (inverse correlation) at the 1-month interval after HoLEP (OR, 3.952; P=0.002; OR, 1.084; P=0.015; and OR,1.084; P=0.015; OR, 0.358; P=0.003, respectively) were significant predictive factors for beginners, and first desire to void (FDV) at 1 month after HoLEP (OR, 1.009; P=0.012) was a significant predictive factor for experienced surgeons in multivariate analysis. Conclusions: Preoperative DO, IPSS, patient age, and surgeon mentorship were significant predictive factors of postoperative patient incontinence for beginner surgeons, while FDV was a significant predictive factors for experienced surgeons. These findings should be taken into account by surgeons performing HoLEP to maximize the patient’s quality of life with regards to urinary continence. PMID

  15. Is reporting of rape on the rise? A comparison of women with reported versus unreported rape experiences in the National Women's Study-Replication.

    PubMed

    Wolitzky-Taylor, Kate B; Resnick, Heidi S; McCauley, Jenna L; Amstadter, Ananda B; Kilpatrick, Dean G; Ruggiero, Kenneth J

    2011-03-01

    Rape affects one in seven women nationwide. Historically, most rape victims do not report rape to law enforcement. Research is needed to identify barriers to reporting and correlates of reporting to guide policy recommendations that address such barriers. We investigated the prevalence of reporting rape among a national sample of women (N = 3,001) interviewed in 2006. The study also examined predictors of reporting as well as barriers to reporting, concerns about reporting, and women's experiences with the reporting process. Results demonstrated that the overall prevalence of reporting (15.8%) has not significantly increased since the 1990s. Differences were found between rape types, with rapes involving drug or alcohol incapacitation or facilitation being less likely to be reported than forcible rapes. Several predictors of reporting emerged in multivariable analyses. Implications for public health and public policy are discussed.

  16. Monte Carlo and discrete ordinates calculations of 14-MeV neutrons streaming through a stainless-steel duct (L/D = 4. 6): comparison with experiment

    SciTech Connect

    Santoro, R.T.; Barnes, J.M.; Alsmiller, R.G. Jr.; Drischler, J.D.

    1985-01-01

    Integral experiments are being carried out at the Oak Ridge National Laboratory to measure neutron and gamma-ray energy spectra from approx. 14 MeV neutrons streaming through cylindrical ducts imbedded in concrete. These data are being used to validate radiation transport code and nuclear data libraries that are being used to calculate nuclear streaming through the penetrations that are found in fusion reactor blanket and shield assemblies. In this paper, measured and calculated neutron and gamma-ray energy spectra from approx. 14 MeV neutrons streaming through a stainless-steel duct having a length-to-dia ratio of 4.6 are compared as a function of detector location relative to the mouth of the duct. The length of the duct is 1.45 m.

  17. Determination of outer molecular orbitals by collisional ionization experiments and comparison with Hartree-Fock, Kohn-Sham, and Dyson orbitals

    SciTech Connect

    Yamazaki, Masakazu; Horio, Takuya; Kishimoto, Naoki; Ohno, Koichi

    2007-03-15

    Although the outer shapes of molecular orbitals (MO's) are of great importance in many phenomena, they have been difficult to be probed by experiments. Here we show that metastable helium (He{sup *}) atoms can sensitively probe the outer properties of molecules and that an electron spectroscopic technique using velocity-selected He{sup *} atoms in combination with classical trajectory simulations leads to a consistent determination of MO functions and the molecular surface. MO functions composed of linear combinations of atomic orbital functions were fitted to the observed collision energy dependences of partial ionization cross sections (CEDPICS). The obtained CEDPICS MO functions were compared with conventionally available Hartree-Fock, Kohn-Sham, and Dyson orbitals.

  18. A comparison of methods and results in recruiting white and black women into reproductive studies: the MMC-PSU cooperative center on reproduction experience.

    PubMed

    Sweet, Stephanie; Legro, Richard S; Coney, PonJola

    2008-07-01

    Establishing a holistic approach for the enrollment of subjects into clinical trials that includes strategies for the recruitment of non-traditional and minority populations has been an elusive task. The existence of such a design, that is understood and embraced by investigators and the target communities, would streamline the current level of commitment of time, energy and resources. This is necessary to successfully encourage individual and community participation in research studies. The Center for Research in Reproduction at Meharry set out to recruit a large number of African American women volunteers of reproductive age into clinical trials. The experience, of recruiting volunteers from the African American community for clinical trials in the Meharry Medical College/Pennsylvania State University (MMC/PSU)'s Cooperative Center for Research in Reproduction at Meharry, is presented.

  19. Comparison of cytogenetic effects in bone marrow of mice after the flight on the biosatellite "BION-M1" and the ground-based radiobiological experiment

    NASA Astrophysics Data System (ADS)

    Dorozhkina, Olga; Vorozhtsova, Svetlana; Ivanov, Alexander

    2016-07-01

    During space flight, the astronauts are exposed to radiation exposure at low doses with low dose rates, so one of the actual areas of Radiobiology is research of action of ionizing radiation in low and ultra-low doses. Violation of the chromosome apparatus of living biosystems, ranging from viruses and bacteria to humans, is the most reliable evidence of exposure to ionizing radiation. In this regard, the study of cytogenetic damage in the cells of humans and animals is central to space radiobiology (Fedorenko B.S., 2006). In experiment "BION - M1" by anaphase method was determined level of chromosomal aberrations in bone marrow cells of tibia of mice. Flight duration biosatellite "BION - M1" (Sychev V.N. et al., 2014) was 30 days in Earth orbit. Euthanasia of experimental animals was carried out after 12 hours from the moment of landing satellite by method of cervical dislocation. The level of chromosomal aberrations in vivarium-housed control mice was 1,75 ± 0,6% and 1,8 ± 0,45%, while the mitotic index 1,46 ± 0,09% and 1,53 ± 0,05%. The content of animals in the experiment with onboard equipment led to some increase in aberrant mitosis (2,3 ± 0,4%) and reduction of the mitotic index (1,37 ± 0,02%). In the flight experiment "BION-M1" was a statistically significant increase in level of chromosome aberrations (29,7 ± 4,18%) and a decrease in the mitotic index (0,74 ± 0,07%). According to VA Shurshakova (2014), the radiation dose to mice ranged from 32 to 72 mGy and relate to a range of small doses (ICRP, 2012). In this connection we conducted a series of experiments in the ground conditions, the aim of which was the study of earliest effects of ionizing radiation in vivo in mice irradiated with low doses of γ-irradiation of 10 to 200 mGy in the first 24 hours after exposure, i.e. within the first post-radiation exposure cell cycle. Studies were carried out on adult female mice outbred ICR (CD-1) - SPF category at the age of 4-4.5 months with an average

  20. Comparison between prediction and experiment for all-movable wing and body combinations at supersonic speeds : lift, pitching moment, and hinge moment

    NASA Technical Reports Server (NTRS)

    Nielsen, Jack N; Kaattari, George E; Drake, William C

    1952-01-01

    A simple method is presented for estimating lift, pitching-moment, and hinge-moment characteristics of all-movable wings in the presence of a body as well as the characteristics of wing-body combinations employing such wings. In general, good agreement between the method and experiment was obtained for the lift and pitching moment of the entire wing-body combination and for the lift of the wing in the presence of the body. The method is valid for moderate angles of attack, wing deflection angles, and width of gap between wing and body. The method of estimating hinge moment was not considered sufficiently accurate for triangular all-movable wings. An alternate procedure is proposed based on the experimental moment characteristics of the wing alone. Further theoretical and experimental work is required to substantiate fully the proposed procedure.

  1. Dependence of the microwave radar cross section on ocean surface variables - Comparison of measurements and theory using data from the Frontal Air-Sea Interaction Experiment

    NASA Technical Reports Server (NTRS)

    Weissman, David E.

    1990-01-01

    The purpose of this investigation was to study the ability of theoretical radar cross section (RCS) models to predict the absolute magnitude of the ocean radar cross section under a wide variety of sea and atmospheric conditions. The dependence of the RCS on wind stress (as opposed to wind speed) was also studied. An extensive amount of experimental data was acquired during the Frontal Air-Sea Interaction Experiment. Measurements across an ocean front demonstrated that the vertical polarization and horizontal polarization radar cross section were more strongly dependent on wind stress than on wind magnitude. Current theoretical models for the RCS, based on stress, were tested with this data. In situations where the Bragg scattering theory does not agree with the measured radar cross section (magnitude and angle dependence), revisions are hypothesized and evaluated.

  2. Examination of important life experiences of the oldest-old: cross-cultural comparisons of U.S. and Japanese centenarians.

    PubMed

    da Rosa, Grace; Martin, Peter; Gondo, Yasuyuki; Hirose, Nobuyoshi; Ishioka, Yoshiko; Poon, Leonard W

    2014-06-01

    The purpose of this study was to compare the most important life events reported by U.S. and Japanese centenarians. This study included a population-based sample of 239 U.S. centenarians from the Georgia Centenarian Study and 304 Japanese centenarians from the Tokyo Centenarian Study. Two open-ended life events questions were categorized and grouped into different life event domains. Several cross-tabulations were computed to investigate culture and gender differences in most important life event domains. Next, four configural frequency analyses were conducted using Neuroticism, Extraversion, and the first most often mentioned life event domain for each sample (i.e., marriage and historical life events). Results suggest that events related to marriage were the most frequent important event domains mentioned by U.S. centenarians. The Japanese sample was more likely to report historical events. Men from the U.S. were more likely to report events related to work and retirement compared to U.S. women, and U.S. women reported events related to family as the most important life events when compared to U.S. men. Japanese women considered events related to marriage, death and grief as the most important life events when compared to Japanese men. In addition, Japanese men reported events related to work and retirement as the most important life events. A cross-cultural difference was found in life events: U.S. centenarians were more likely to mention positive experiences related to marriage and children, whereas Japanese centenarians reported mostly negative and traumatic experiences such as historical, death/grief, and work/retirement events.

  3. Coarse-grained models for fluids and their mixtures: Comparison of Monte Carlo studies of their phase behavior with perturbation theory and experiment

    NASA Astrophysics Data System (ADS)

    Mognetti, B. M.; Virnau, P.; Yelash, L.; Paul, W.; Binder, K.; Müller, M.; MacDowell, L. G.

    2009-01-01

    The prediction of the equation of state and the phase behavior of simple fluids (noble gases, carbon dioxide, benzene, methane, and short alkane chains) and their mixtures by Monte Carlo computer simulation and analytic approximations based on thermodynamic perturbation theory is discussed. Molecules are described by coarse grained models, where either the whole molecule (carbon dioxide, benzene, and methane) or a group of a few successive CH2 groups (in the case of alkanes) are lumped into an effective point particle. Interactions among these point particles are fitted by Lennard-Jones (LJ) potentials such that the vapor-liquid critical point of the fluid is reproduced in agreement with experiment; in the case of quadrupolar molecules a quadrupole-quadrupole interaction is included. These models are shown to provide a satisfactory description of the liquid-vapor phase diagram of these pure fluids. Investigations of mixtures, using the Lorentz-Berthelot (LB) combining rule, also produce satisfactory results if compared with experiment, while in some previous attempts (in which polar solvents were modeled without explicitly taking into account quadrupolar interaction), strong violations of the LB rules were required. For this reason, the present investigation is a step towards predictive modeling of polar mixtures at low computational cost. In many cases Monte Carlo simulations of such models (employing the grand-canonical ensemble together with reweighting techniques, successive umbrella sampling, and finite size scaling) yield accurate results in very good agreement with experimental data. Simulation results are quantitatively compared to an analytical approximation for the equation of state of the same model, which is computationally much more efficient, and some systematic discrepancies are discussed. These very simple coarse-grained models of small molecules developed here should be useful, e.g., for simulations of polymer solutions with such molecules as

  4. Coarse-grained models for fluids and their mixtures: Comparison of Monte Carlo studies of their phase behavior with perturbation theory and experiment.

    PubMed

    Mognetti, B M; Virnau, P; Yelash, L; Paul, W; Binder, K; Müller, M; MacDowell, L G

    2009-01-28

    The prediction of the equation of state and the phase behavior of simple fluids (noble gases, carbon dioxide, benzene, methane, and short alkane chains) and their mixtures by Monte Carlo computer simulation and analytic approximations based on thermodynamic perturbation theory is discussed. Molecules are described by coarse grained models, where either the whole molecule (carbon dioxide, benzene, and methane) or a group of a few successive CH(2) groups (in the case of alkanes) are lumped into an effective point particle. Interactions among these point particles are fitted by Lennard-Jones (LJ) potentials such that the vapor-liquid critical point of the fluid is reproduced in agreement with experiment; in the case of quadrupolar molecules a quadrupole-quadrupole interaction is included. These models are shown to provide a satisfactory description of the liquid-vapor phase diagram of these pure fluids. Investigations of mixtures, using the Lorentz-Berthelot (LB) combining rule, also produce satisfactory results if compared with experiment, while in some previous attempts (in which polar solvents were modeled without explicitly taking into account quadrupolar interaction), strong violations of the LB rules were required. For this reason, the present investigation is a step towards predictive modeling of polar mixtures at low computational cost. In many cases Monte Carlo simulations of such models (employing the grand-canonical ensemble together with reweighting techniques, successive umbrella sampling, and finite size scaling) yield accurate results in very good agreement with experimental data. Simulation results are quantitatively compared to an analytical approximation for the equation of state of the same model, which is computationally much more efficient, and some systematic discrepancies are discussed. These very simple coarse-grained models of small molecules developed here should be useful, e.g., for simulations of polymer solutions with such molecules as

  5. Quantum calculations of the IR spectrum of liquid water using ab initio and model potential and dipole moment surfaces and comparison with experiment

    NASA Astrophysics Data System (ADS)

    Liu, Hanchao; Wang, Yimin; Bowman, Joel M.

    2015-05-01

    The calculation and characterization of the IR spectrum of liquid water have remained a challenge for theory. In this paper, we address this challenge using a combination of ab initio approaches, namely, a quantum treatment of IR spectrum using the ab initio WHBB water potential energy surface and a refined ab initio dipole moment surface. The quantum treatment is based on the embedded local monomer method, in which the three intramolecular modes of each embedded H2O monomer are fully coupled and also coupled singly to each of six intermolecular modes. The new dipole moment surface consists of a previous spectroscopically accurate 1-body dipole moment surface and a newly fitted ab initio intrinsic 2-body dipole moment. A detailed analysis of the new dipole moment surface in terms of the coordinate dependence of the effective atomic charges is done along with tests of it for the water dimer and prism hexamer double-harmonic spectra against direct ab initio calculations. The liquid configurations are taken from previous molecular dynamics calculations of Skinner and co-workers, using the TIP4P plus E3B rigid monomer water potential. The IR spectrum of water at 300 K in the range of 0-4000 cm-1 is calculated and compared with experiment, using the ab initio WHBB potential and new ab initio dipole moment, the q-TIP4P/F potential, which has a fixed-charged description of the dipole moment, and the TTM3-F potential and dipole moment surfaces. The newly calculated ab initio spectrum is in very good agreement with experiment throughout the above spectral range, both in band positions and intensities. This contrasts to results with the other potentials and dipole moments, especially the fixed-charge q-TIP4P/F model, which gives unrealistic intensities. The calculated ab initio spectrum is analyzed by examining the contribution of various transitions to each band.

  6. Quantum calculations of the IR spectrum of liquid water using ab initio and model potential and dipole moment surfaces and comparison with experiment

    SciTech Connect

    Liu, Hanchao; Wang, Yimin; Bowman, Joel M.

    2015-05-21

    The calculation and characterization of the IR spectrum of liquid water have remained a challenge for theory. In this paper, we address this challenge using a combination of ab initio approaches, namely, a quantum treatment of IR spectrum using the ab initio WHBB water potential energy surface and a refined ab initio dipole moment surface. The quantum treatment is based on the embedded local monomer method, in which the three intramolecular modes of each embedded H{sub 2}O monomer are fully coupled and also coupled singly to each of six intermolecular modes. The new dipole moment surface consists of a previous spectroscopically accurate 1-body dipole moment surface and a newly fitted ab initio intrinsic 2-body dipole moment. A detailed analysis of the new dipole moment surface in terms of the coordinate dependence of the effective atomic charges is done along with tests of it for the water dimer and prism hexamer double-harmonic spectra against direct ab initio calculations. The liquid configurations are taken from previous molecular dynamics calculations of Skinner and co-workers, using the TIP4P plus E3B rigid monomer water potential. The IR spectrum of water at 300 K in the range of 0–4000 cm{sup −1} is calculated and compared with experiment, using the ab initio WHBB potential and new ab initio dipole moment, the q-TIP4P/F potential, which has a fixed-charged description of the dipole moment, and the TTM3-F potential and dipole moment surfaces. The newly calculated ab initio spectrum is in very good agreement with experiment throughout the above spectral range, both in band positions and intensities. This contrasts to results with the other potentials and dipole moments, especially the fixed-charge q-TIP4P/F model, which gives unrealistic intensities. The calculated ab initio spectrum is analyzed by examining the contribution of various transitions to each band.

  7. Chemical dynamics simulations of the monohydrated OH(-)(H2O) + CH3I reaction. Atomic-level mechanisms and comparison with experiment.

    PubMed

    Xie, Jing; Otto, Rico; Wester, Roland; Hase, William L

    2015-06-28

    Direct dynamics simulations, with B97-1/ECP/d theory, were performed to study the role of microsolvation for the OH(-)(H2O) + CH3I reaction. The SN2 reaction dominates at all reactant collision energies, but at higher collision energies proton transfer to form CH2I(-), and to a lesser extent CH2I(-) (H2O), becomes important. The SN2 reaction occurs by direct rebound and stripping mechanisms, and 28 different indirect atomistic mechanisms, with the latter dominating. Important components of the indirect mechanisms are the roundabout and formation of SN2 and proton transfer pre-reaction complexes and intermediates, including [CH3--I--OH](-). In contrast, for the unsolvated OH(-) + CH3I SN2 reaction, there are only seven indirect atomistic mechanisms and the direct mechanisms dominate. Overall, the simulation results for the OH(-)(H2O) + CH3I SN2 reaction are in good agreement with experiment with respect to reaction rate constant, product branching ratio, etc. Differences between simulation and experiment are present for the SN2 velocity scattering angle at high collision energies and the proton transfer probability at low collision energies. Equilibrium solvation by the H2O molecule is unimportant. The SN2 reaction is dominated by events in which H2O leaves the reactive system as CH3OH is formed or before CH3OH formation. Formation of solvated products is unimportant and participation of the (H2O)CH3OH---I(-) post-reaction complex for the SN2 reaction is negligible.

  8. A comparison of the psychological burden of PET/MRI and PET/CT scans and association to initial state anxiety and previous imaging experiences

    PubMed Central

    Neriman, D; Hoath, J; Millner, L; Endozo, R; Azzopardi, G; O'Meara, C; Bomanji, J; Groves, A M

    2015-01-01

    Objective: To investigate the level of psychological burden experienced by patients undergoing positron emission tomography (PET)/MRI scanning compared with PET/CT. Methods: 100 adult patients referred for PET/CT and underwent PET/MRI scanning were eligible. Initial state, psychological burden of PET/CT and PET/MRI, scan satisfaction and preference were assessed using a purpose-designed questionnaire, comprising 61 five-point Likert scale questions and a three-point tick box question indicating preference between PET/CT and PET/MRI. State anxiety was assessed using the state portion of the State Trait Anxiety Inventory. Wilcoxon signed-rank tests compared psychological burden experienced by participants following PET/CT and PET/MRI scan. Results: A greater level of psychological burden was experienced by patients during PET/MRI than PET/CT p ≤ 0.001, consistent with patients' preference for PET/CT over PET/MRI (p = 0.013). There was a significant relationship between PET/CT psychological burden and initial state (r = 0.386, p ≤ 0.001). No significant relationship was identified between Initial state and psychological burden of PET MRI (r = −0.089; p = 217). There was a significant relationship between psychological burden of PET/CT and PET/MRI (r = 0.354; p = 0.001). Conclusion: Patients' experience increased psychological burden during PET/MRI compared with PET/CT. Previous scanning experiences and patients' interactions prior to and during PET/MRI improved patient satisfaction. Interventions could be implemented to improve imaging outcome. Advances in knowledge: This study provides evidence for the increased psychological burden of PET/MRI compared with PET/CT, and that people prefer the PET/CT procedure. We have shown that the patients who expressed a preference for PET/MRI demonstrated significantly lower psychological burden for that procedure than those that preferred PET/CT, which indicates that the benefit of reduced

  9. MO-E-17A-03: Monte Carlo CT Dose Calculation: A Comparison Between Experiment and Simulation Using ARCHER-CT

    SciTech Connect

    Liu, T; Du, X; Su, L; Gao, Y; Ji, W; Xu, X; Zhang, D; Shi, J; Liu, B; Kalra, M

    2014-06-15

    Purpose: To compare the CT doses derived from the experiments and GPU-based Monte Carlo (MC) simulations, using a human cadaver and ATOM phantom. Methods: The cadaver of an 88-year old male and the ATOM phantom were scanned by a GE LightSpeed Pro 16 MDCT. For the cadaver study, the Thimble chambers (Model 10×5−0.6CT and 10×6−0.6CT) were used to measure the absorbed dose in different deep and superficial organs. Whole-body scans were first performed to construct a complete image database for MC simulations. Abdomen/pelvis helical scans were then conducted using 120/100 kVps, 300 mAs and a pitch factor of 1.375:1. For the ATOM phantom study, the OSL dosimeters were used and helical scans were performed using 120 kVp and x, y, z tube current modulation (TCM). For the MC simulations, sufficient particles were run in both cases such that the statistical errors of the results by ARCHER-CT were limited to 1%. Results: For the human cadaver scan, the doses to the stomach, liver, colon, left kidney, pancreas and urinary bladder were compared. The difference between experiments and simulations was within 19% for the 120 kVp and 25% for the 100 kVp. For the ATOM phantom scan, the doses to the lung, thyroid, esophagus, heart, stomach, liver, spleen, kidneys and thymus were compared. The difference was 39.2% for the esophagus, and within 16% for all other organs. Conclusion: In this study the experimental and simulated CT doses were compared. Their difference is primarily attributed to the systematic errors of the MC simulations, including the accuracy of the bowtie filter modeling, and the algorithm to generate voxelized phantom from DICOM images. The experimental error is considered small and may arise from the dosimeters. R01 grant (R01EB015478) from National Institute of Biomedical Imaging and Bioengineering.

  10. Hydraulic evolution of high-density turbidity currents from the Brushy Canyon Formation, Eddy County, New Mexico inferred by comparison to settling and sorting experiments

    NASA Astrophysics Data System (ADS)

    Motanated, Kannipa; Tice, Michael M.

    2016-05-01

    Hydraulic transformations in turbidity currents are commonly driven by or reflected in changes in suspended sediment concentrations, but changes preceding transformations can be difficult to diagnose because they do not produce qualitative changes in resultant deposits. This study integrates particle settling experiments and in situ detection of hydraulically contrasting particles in turbidites in order to infer changes in suspended sediment concentration during deposition of massive (Bouma Ta) sandstone divisions. Because grains of contrasting density are differentially sorted during hindered settling from dense suspensions, relative grading patterns can be used to estimate suspended sediment concentrations and interpret hydraulic evolution of the depositing turbidity currents. Differential settling of dense particles (aluminum ballotini) through suspensions of hydraulically coarser light particles (silica ballotini) with volumetric concentration, Cv, were studied in a thin vessel by using particle-image-velocimetry. At high Cv, aluminum particles were less retarded than co-sedimenting silica particles, and effectively settled as hydraulically coarser grains. This was because particles were entrained into clusters dominated by the settling behavior of the silica particles. Terminal settling velocities of both particles converged at Cv ≥ 25%, and particle sorting was diminished. The results of settling experiments were applied to understand settling of analogous feldspar and zircon grains in natural turbidity flows. Distributions of light and heavy mineral grains in massive sandstones, Bouma Ta divisions, of turbidites from the Middle Permian Brushy Canyon Formation were observed in situ by X-ray fluorescence microscopy (μXRF). Hydraulic sorting of these grains resulted in characteristic patterns of zirconium abundance that decreased from base to top within Ta divisions. These profiles resulted from upward fining of zircon grains with respect to co

  11. Multi-Layer Arctic Mixed-Phase Clouds Simulated by a Cloud-Resolving Model: Comparison with ARM Observations and Sensitivity Experiments

    NASA Technical Reports Server (NTRS)

    Luo, Yali; Xu, Kuan-Man; Morrison, Hugh; McFarquhar, Greg M.; Wang, Zhien; Zhang, Gong

    2007-01-01

    A cloud-resolving model (CRM) is used to simulate the multiple-layer mixed-phase stratiform (MPS) clouds that occurred during a three-and-a-half day subperiod of the Department of Energy-Atmospheric Radiation Measurement Program s Mixed-Phase Arctic Cloud Experiment (M-PACE). The CRM is implemented with an advanced two-moment microphysics scheme, a state-of-the-art radiative transfer scheme, and a complicated third-order turbulence closure. Concurrent meteorological, aerosol, and ice nucleus measurements are used to initialize the CRM. The CRM is prescribed by time-varying large-scale advective tendencies of temperature and moisture and surface turbulent fluxes of sensible and latent heat. The CRM reproduces the occurrences of the single- and double-layer MPS clouds as revealed by the M-PACE observations. However, the simulated first cloud layer is lower and the second cloud layer thicker compared to observations. The magnitude of the simulated liquid water path agrees with that observed, but its temporal variation is more pronounced than that observed. As in an earlier study of single-layer cloud, the CRM also captures the major characteristics in the vertical distributions and temporal variations of liquid water content (LWC), total ice water content (IWC), droplet number concentration and ice crystal number concentration (nis) as suggested by the aircraft observations. However, the simulated mean values differ significantly from the observed. The magnitude of nis is especially underestimated by one order of magnitude. Sensitivity experiments suggest that the lower cloud layer is closely related to the surface fluxes of sensible and latent heat; the upper cloud layer is probably initialized by the large-scale advective cooling/moistening and maintained through the strong longwave (LW) radiative cooling near the cloud top which enhances the dynamical circulation; artificially turning off all ice-phase microphysical processes results in an increase in LWP by a

  12. Ensemble urban flood simulation in comparison with laboratory-scale experiments: Impact of interaction models for manhole, sewer pipe, and surface flow

    NASA Astrophysics Data System (ADS)

    Noh, Seong Jin; Lee, Seungsoo; An, Hyunuk; Kawaike, Kenji; Nakagawa, Hajime

    2016-11-01

    An urban flood is an integrated phenomenon that is affected by various uncertainty sources such as input forcing, model parameters, complex geometry, and exchanges of flow among different domains in surfaces and subsurfaces. Despite considerable advances in urban flood modeling techniques, limited knowledge is currently available with regard to the impact of dynamic interaction among different flow domains on urban floods. In this paper, an ensemble method for urban flood modeling is presented to consider the parameter uncertainty of interaction models among a manhole, a sewer pipe, and surface flow. Laboratory-scale experiments on urban flood and inundation are performed under various flow conditions to investigate the parameter uncertainty of interaction models. The results show that ensemble simulation using interaction models based on weir and orifice formulas reproduces experimental data with high accuracy and detects the identifiability of model parameters. Among interaction-related parameters, the parameters of the sewer-manhole interaction show lower uncertainty than those of the sewer-surface interaction. Experimental data obtained under unsteady-state conditions are more informative than those obtained under steady-state conditions to assess the parameter uncertainty of interaction models. Although the optimal parameters vary according to the flow conditions, the difference is marginal. Simulation results also confirm the capability of the interaction models and the potential of the ensemble-based approaches to facilitate urban flood simulation.

  13. Comparison of stratospheric aerosol and gas experiment I (SAGE I) and Umkehr ozone profiles including a search for Umkehr aerosol effects

    SciTech Connect

    Newchurch, M.J.

    1986-01-01

    After briefly reviewing ozone depletion predictions from atmospheric models and results from trend analysis of Umkehr data, this paper outlines the Umkehr method for deducing the vertical profile of ozone and reviews the theoretical and empirical studies of the aerosol effect on Umkehr measurements. A brief description of the Stratospheric Aerosol and Gas Experiment I (SAGE I) is followed by a method for approximating the best representation of the conditions over the Umkehr ground site as seen by the SAGE I satellite. Using a spatially weighted average of SAGE I events derived from an autocorrelation analysis, the authors find 337 co-located SAGE I and Umkehr events. The approximate total column ozone measured by SAGE I is 5% higher than that measured by Umkehr on average. Most of this difference resides in Umkehr layer two, three, and four, while layers seven, eight, and nine contain small differences in average ozone content. Intercomparison with four other ozone studies indicates agreement between SAGE I and SBUV in most layers and at most Umkehr stations north of 30/sup 0/. However, significant differences in Umkehr layer eight between SAGE I and SBUV remain. Ozone differences between SAGE I and Umkehr are strong functions of both total column ozone and season in the lower layers but not in the upper layers.

  14. H2O-CH4 and H2S-CH4 complexes: a direct comparison through molecular beam experiments and ab initio calculations.

    PubMed

    Cappelletti, David; Bartocci, Alessio; Frati, Federica; Roncaratti, Luiz F; Belpassi, Leonardo; Tarantelli, Francesco; Lakshmi, Prabha Aiswarya; Arunan, Elangannan; Pirani, Fernando

    2015-11-11

    New molecular beam scattering experiments have been performed to measure the total (elastic plus inelastic) cross sections as a function of the velocity in collisions between water and hydrogen sulfide projectile molecules and the methane target. Measured data have been exploited to characterize the range and strength of the intermolecular interaction in such systems, which are of relevance as they drive the gas phase molecular dynamics and the clathrate formation. Complementary information has been obtained by rotational spectra, recorded for the hydrogen sulfide-methane complex, with a pulsed nozzle Fourier transform microwave spectrometer. Extensive ab initio calculations have been performed to rationalize all the experimental findings. The combination of experimental and theoretical information has established the ground for the understanding of the nature of the interaction and allows for its basic components to be modelled, including charge transfer, in these weakly bound systems. The intermolecular potential for H2S-CH4 is significantly less anisotropic than for H2O-CH4, although both of them have potential minima that can be characterized as 'hydrogen bonded'.

  15. Development of numerical model to investigate the laser driven shock waves from aluminum target into ambient air at atmospheric pressure and its comparison with experiment

    NASA Astrophysics Data System (ADS)

    Paturi, Prem Kiran; Sakaraboina, Sai Shiva; Chelikani, Leela; Ikkurthi, Venkata Ramana; C. D., Sijoy; Chaturvedi, Shashank; Acrhem Collaboration; Cad Collaboration

    2015-06-01

    A one-dimensional, three-temperature (electron, ion and thermal radiation) numerical model to study the laser induced shock wave (LISW) propagation from aluminum target in ambient air at atmospheric pressure is developed. The hydrodynamic equations of mass, momentum and energy are solved by using an implicit scheme in Lagrangian form. The model considers the laser absorption to take place via inverse-bremsstrahlung due to electron-ion (e-i) process. The flux limited electron thermal energy transport and e-i thermal energy relaxation equations are solved implicitly. The experimental characterization of spatio-temporal evolution of the LISW in air generated by focusing a second harmonic (532 nm, 7ns) of Nd:YAG laser on to surface of Al is performed using shadowgraphy technique with a temporal resolution of 1.5 ns. The radius of SW (2 - 5 mm) and its pressure (40 - 80 MPa) observed in the experiments over 0.2 μs-10 μs time scales were comparable with the numerical results for laser intensities ranging from 2.0 × 1010 to 1.4 × 1011 W/cm2. The work is supported by Defence Research and Developement Organization, India through Grants-in-Aid Program.

  16. Phytoremediation and microbial community structure of soil from a metal-contaminated military shooting range: comparisons of field and pot experiments.

    PubMed

    Kim, Sunghyun; Baek, Kyunghwa; Lee, Insook

    2010-01-01

    In this study, the heavy metal uptake ability of two plant species, barnyard grass and Indian mallow, and the effects of associated micro-communities on the rhizosphere of these plants were investigated in metal-contaminated sites. In addition, the effectiveness of phytoremediation using these plants was compared under field and pot conditions. To accomplish this analysis, phytoremediation of general military shooting range soil was conducted for 8 weeks under the two conditions. The results showed that metal uptake by plants and reductions in soil metal concentration were lower in the field than in pots. However, soil dehydrogenase activities and microbial diversity increased in response to phytoremediation in the field. Specifically, the soil dehydrogenase activities of barnyard grass in field soils were 3-fold higher than those of potted soils. Moreover, the denaturing gradient gel electrophoresis patterns revealed that groups formed according to plant species. Finally, the Shannon-Weaver diversity index and Simpson dominance index were higher in the rhizosphere of barnyard grass than in the rhizosphere of Indian mallow under field conditions. These results indicate that it is difficult to apply the results obtained from pot experiments to field conditions. These findings can be used to inform future studies conducted to determine if field sites are suitable for phytoremediation based on the results of pot studies. PMID:20390882

  17. Phytoremediation and microbial community structure of soil from a metal-contaminated military shooting range: comparisons of field and pot experiments.

    PubMed

    Kim, Sunghyun; Baek, Kyunghwa; Lee, Insook

    2010-01-01

    In this study, the heavy metal uptake ability of two plant species, barnyard grass and Indian mallow, and the effects of associated micro-communities on the rhizosphere of these plants were investigated in metal-contaminated sites. In addition, the effectiveness of phytoremediation using these plants was compared under field and pot conditions. To accomplish this analysis, phytoremediation of general military shooting range soil was conducted for 8 weeks under the two conditions. The results showed that metal uptake by plants and reductions in soil metal concentration were lower in the field than in pots. However, soil dehydrogenase activities and microbial diversity increased in response to phytoremediation in the field. Specifically, the soil dehydrogenase activities of barnyard grass in field soils were 3-fold higher than those of potted soils. Moreover, the denaturing gradient gel electrophoresis patterns revealed that groups formed according to plant species. Finally, the Shannon-Weaver diversity index and Simpson dominance index were higher in the rhizosphere of barnyard grass than in the rhizosphere of Indian mallow under field conditions. These results indicate that it is difficult to apply the results obtained from pot experiments to field conditions. These findings can be used to inform future studies conducted to determine if field sites are suitable for phytoremediation based on the results of pot studies.

  18. Investigation of the validity of BEM for simulation of wind turbines in complex load cases and comparison with experiment and CFD

    NASA Astrophysics Data System (ADS)

    Rahimi, H.; Dose, B.; Stoevesandt, B.; Peinke, J.

    2016-09-01

    The aim of this work is to investigate the validity of simulation codes based on the Blade Element Momentum (BEM) theory for three important design load conditions. This paper includes the cases of yawed inflow, rotor tower interaction for downwind turbines and the standstill case. Computational Fluid Dynamics (CFD) and experimental data (when available) are used for the evaluation of the obtained results. For the yawed inflow, the results indicate that significant deviations between BEM and experiments & CFD can be observed. This discrepancy is caused by unsteady phenomena such as the advancing & retreating blade effect and the skewed wake effect. In the case of the rotor and tower interaction of the downwind turbine, the results show that the BEM based code overpredicts the sectional forces in terms of the normal and tangential forces by 20%. In the case of standstill, the evaluation of the results based on tip deflections shows clear differences in the output of both numerical approaches. While the flapwise deflections show a reasonable agreement, the CFD-based coupled solver predicts much larger edgewise vibrations.

  19. The Comparison of Self-differentiation and Self-concept in Divorced and Non-divorced Women Who Experience Domestic Violence

    PubMed Central

    Sheikh, Fatemeh; Khodabakhshi Koolaee, Anahita; Rahmati Zadeh, Masoumeh

    2013-01-01

    Background A number of researches indicate that domestic violence (DV) causes abuse and vulnerability of women and children. Two components that can decrease violence and divorce are self-concept and self-differentiation. Objectives In this research, we compare self-differentiation and self-concept in divorced and non-divorced women that experience domestic violence. Materials and Methods To achieve the goal of the research, 80 divorced women with domestic violence were chosen through available sampling and equalized with 80 non divorced women with domestic violence in aspect of age and education. They respond to instrument of self-differentiation (Skowron) and self-concept (Rodgers). Data was analyzed between the two groups using independent t-test. The significant level was (P < 0.01). Results The findings indicated divorced women have more self-differentiation and self-concept than non-divorced women. In addition, there is a significant difference with respect to self-differentiation and self-concept in divorced and non-divorced women with domestic violence. Conclusions These results emphasize that self-differentiation and self-concept can be considered in premarital education (therapeutic interventions) to protective conditions against the occurrence of DV. PMID:24971277

  20. Comparison of five benchmarks

    SciTech Connect

    Huss, J. E.; Pennline, J. A.

    1987-02-01

    Five benchmark programs were obtained and run on the NASA Lewis CRAY X-MP/24. A comparison was made between the programs codes and between the methods for calculating performance figures. Several multitasking jobs were run to gain experience in how parallel performance is measured.

  1. Comparison between knife-edge and frisbee-shaped surrogate surfaces for making dry deposition measurements: Wind tunnel experiments and computational fluid dynamics (CFD) modeling

    NASA Astrophysics Data System (ADS)

    Huang, Jiaoyan; Liu, Ying; Holsen, Thomas M.

    2011-08-01

    Dry deposition is a major pathway for atmospheric contaminant movement from the atmosphere to the earth surface. Despite its importance, there is no generally accepted direct method to measure dry deposition. Recently, the interest in using surrogate surfaces to measure dry deposition is growing, primarily because of their ease of use. However, a problem with these surfaces is extrapolating the results obtained to natural surfaces. There are two popular surrogate plates used to measure dry deposition. One had a sharp leading edge (knife-edge) (KSS), and the other has a smooth-edge (frisbee-shaped) (FSS). In this study, the performances of these two surrogate surfaces to directly measure gas dry deposition were explored using wind tunnel experiments and two-dimensional (2D) computational fluid dynamic (CFD) models. Although the fluid fields above these two plates were different, both created laminar boundary layers (distance above the surface where the velocity gradient is constant) with a constant thickness after approximately five cm. In the wind tunnel, gaseous elemental mercury (GEM) deposition to gold-coated filters was used to measure deposition velocities ( Vd) in part because for this combination deposition is air-side controlled. The GEM Vd to both surfaces increased with increasing wind speeds. Based on both measurements and CFD simulations, the Vds to the FSS were approximately 30% higher and more variable than to the KSS when the wind flow was parallel to the surfaces. However, when the angle between the surfaces and the wind was varied the Vds to the FSS were less dependent on the incident angle than to the KSS.

  2. The influence of bone density and anisotropy in finite element models of distal radius fracture osteosynthesis: Evaluations and comparison to experiments.

    PubMed

    Synek, A; Chevalier, Y; Baumbach, S F; Pahr, D H

    2015-11-26

    Continuum-level finite element (FE) models can be used to analyze and improve osteosynthesis procedures for distal radius fractures (DRF) from a biomechanical point of view. However, previous models oversimplified the bone material and lacked thorough experimental validation. The goal of this study was to assess the influence of local bone density and anisotropy in FE models of DRF osteosynthesis for predictions of axial stiffness, implant plate stresses, and screw loads. Experiments and FE analysis were conducted in 25 fresh frozen cadaveric radii with DRFs treated by volar locking plate osteosynthesis. Specimen specific geometries were captured using clinical quantitative CT (QCT) scans of the prepared samples. Local bone material properties were computed based on high resolution CT (HR-pQCT) scans of the intact radii. The axial stiffness and individual screw loads were evaluated in FE models, with (1) orthotropic inhomogeneous (OrthoInhom), (2) isotropic inhomogeneous (IsoInhom), and (3) isotropic homogeneous (IsoHom) bone material and compared to the experimental axial stiffness and screw-plate interface failures. FE simulated and experimental axial stiffness correlated significantly (p<0.0001) for all three model types. The coefficient of determination was similar for OrthoInhom (R(2)=0.807) and IsoInhom (R(2)=0.816) models but considerably lower for IsoHom models (R(2)=0.500). The peak screw loads were in qualitative agreement with experimental screw-plate interface failure. Individual loads and implant plate stresses of IsoHom models differed significantly (p<0.05) from OrthoInhom and IsoInhom models. In conclusion, including local bone density in FE models of DRF osteosynthesis is essential whereas local bone anisotropy hardly effects the models׳ predictive abilities.

  3. Gravity Recovery and Climate Experiment (GRACE) detection of water storage changes in the Three Gorges Reservoir of China and comparison with in situ measurements

    NASA Astrophysics Data System (ADS)

    Wang, Xianwei; de Linage, Caroline; Famiglietti, James; Zender, Charles S.

    2011-12-01

    Water impoundment in the Three Gorges Reservoir (TGR) of China caused a large mass redistribution from the oceans to a concentrated land area in a short time period. We show that this mass shift is captured by the Gravity Recovery and Climate Experiment (GRACE) unconstrained global solutions at a 400 km spatial resolution after removing correlated errors. The WaterGAP Global Hydrology Model (WGHM) is selected to isolate the TGR contribution from regional water storage changes. For the first time, this study compares the GRACE (minus WGHM) estimated TGR volume changes with in situ measurements from April 2002 to May 2010 at a monthly time scale. During the 8 year study period, GRACE-WGHM estimated TGR volume changes show an increasing trend consistent with the TGR in situ measurements and lead to similar estimates of impounded water volume. GRACE-WGHM estimated total volume increase agrees to within 14% (3.2 km3) of the in situ measurements. This indicates that GRACE can retrieve the true amplitudes of large surface water storage changes in a concentrated area that is much smaller than the spatial resolution of its global harmonic solutions. The GRACE-WGHM estimated TGR monthly volume changes explain 76% (r2 = 0.76) of in situ measurement monthly variability and have an uncertainty of 4.62 km3. Our results also indicate reservoir leakage and groundwater recharge due to TGR filling and contamination from neighboring lakes are nonnegligible in the GRACE total water storage changes. Moreover, GRACE observations could provide a relatively accurate estimate of global water volume withheld by newly constructed large reservoirs and their impacts on global sea level rise since 2002.

  4. The relationship between paranormal beliefs and the personality trait Openness to Experience: A comparison of psychology majors with students in other disciplines

    NASA Astrophysics Data System (ADS)

    Ozkan, Eric Dogan

    Paranormal beliefs (PB) are those that lie outside the explanatory realm of science. Thus, the existence of PB within a particular field of scholarship might indicate a decreased reliance on scientific methods within that field. This study evaluated the extent of PB among undergraduates majoring in the traditional sciences (biology, chemistry, and physics), psychology, and the arts and humanities. In particular, the relationship between PB and the personality trait Openness to Experience (OTE) was investigated, the goal being to both identify specific determinants of PB and better understand why PB are more prevalent in psychology compared with traditional sciences. Students majoring in the sciences, psychology, or arts and humanities were assessed across six domains of PB and six facets of the global personality trait OTE. Additionally, estimates of science education (SE) and IQ were obtained for each subject. Relationships among these variables were predicted to support the hypothesis that PB are largely determined by OTE rather than SE or IQ. Furthermore, it was hypothesized that the prevalence of PB in contemporary psychology could be explained by a relative overabundance of PB and OTE within psychology majors when compared with science majors. The obtained results confirmed that psychology majors were significantly higher in both PB and OTE compared to science majors. Furthermore, psychology majors scored lower than arts and humanities majors in PB and OTE, supporting the notion that psychology as a field occupies a position intermediate between the traditional sciences and the humanities. Regarding the determinants of PB, while SE and IQ were both shown to be significant, OTE was the single most powerful predictor of PB when considering the entire, undifferentiated sample. An unanticipated result was that determinants of PB are substantially gender-related. Among females, PB were predicted by OTE though not SE, while among males, PB were predicted by SE and

  5. Ex Vivo Experiment of Saline-Enhanced Hepatic Bipolar Radiofrequency Ablation with a Perfused Needle Electrode: Comparison with Conventional Monopolar and Simultaneous Monopolar Modes

    SciTech Connect

    Lee, Jeong Min Kim, Se Hyung; Han, Joon Koo; Sohn, Kyu Li; Choi, Byung Ihn

    2005-04-15

    The purpose of this study was to validate the saline-enhanced bipolar radiofrequency ablation (RFA) technique using a perfused electrode to increase RF-created coagulation necrosis, to compare that technique with monopolar RFAs and to find appropriate concentrations and volumes of perfused NaCl solution for the bipolar RFA. A total of 90 ablations were performed in explanted bovine livers. In the initial experiments to determine appropriate conditions for bipolar RFA, we created five thermal ablation zones in each condition, with instillations of varied concentrations (0.9-36%) or injection rates (30 mL/hr-120 mL/hr) of NaCl solution. After placement of one or two 16-gauge open-perfused electrodes into bovine livers, the NaCl solution was instilled into the tissue through the electrode. In the second part of the study, 10 ablation zones were created using one or two perfused electrodes for each of five groups under different conditions: a conventional monopolar mode with 0.9% NaCl solution (group A) or with 6% NaCl solution (group B), a simultaneous monopolar mode with 6% NaCl solution (group C) and a bipolar mode with 6% NaCl solution (groups D and E). RF was applied to each electrode for 20 min in groups A, B, C, and E, or for 10 min in group D. During RFA, we measured the tissue temperature 15 mm from the electrode. The temperature changes during the RFA and the dimensions of the ablation zones were compared among the groups. Bipolar RFA created larger short-axis diameters of coagulation necrosis with 6% NaCl solution (35.8 {+-} 15 mm) than with 0.9% NaCl solution (17 {+-} 9.7 mm) (P < 0.05). However, concentrations of NaCl solution above 6% did not further increase the extent of coagulation necrosis. In addition, bipolar RFA with 6% NaCl solution instillation at a rate of 1.0 mL/min (37.9 {+-} 5.4 mm) or 2.0 mL/min (35.6 {+-} 9.3 mm) produced larger diameters at the mid-point between the electrodes of the ablated lesion than did 0.5 mL/min (25.8 {+-} 9.3 mm) (P

  6. Influence of LOTUS concrete structure, boron-loaded sheets, and B[sub 4]C filter on the integral tritium production of a nature lithium graphite-reflected blanket and comparison with experiment

    SciTech Connect

    Joneja, O.P.; Schneeberger, J.P. ); Nargundkar, V.R. )

    1993-07-01

    Integral tritium production rate (TPR) measurements are important in comparisons of calculations to ascertain the suitability of computer codes and cross-section sets used in calculation. At the LOTUS facility, one of the objectives is to make measurements with different types of pure fusion and hybrid blankets and compare the results with calculations. Since the concrete cavity housing the blankets is small, it is of direct relevance to determine the influence of room-reflected neutrons on the integral TPR and, if possible, to reduce this effect by special absorbers. The effects on the TPR of a stainless steel-natural lithium-graphite-reflected blanket due to the concrete structure, B[sub 4]C filter, and boron-loaded sheets covering the assembly are studied. Calculations are performed by the MCNP Monte Carlo code. Since the room-returned component depends strongly on the composition of the concrete and, more-over, does not correspond to a real blanket situation, it is advisable to compare measurements with calculations for the region where such interference is minimal. A central region is identified for the purpose of comparison. In addition to calculations for a fully homogenized blanket, the important central blanket region is considered in the form of rods, and the remaining blanket as a homogeneous region, to assess the effect of neutron streaming on the TPR of the assembly. An experiment is done by irradiating several Li[sub 2]CO[sub 3] probes positioned in each tube so that the central region of interest is fully covered. The activity of the probes is measured by the standard liquid scintillation method, and the TPR for the entire region can be derived from the experimental reaction rate data. The complete details of the calculational model and the experimental procedure are provided. Good agreement is found between the calculated and experimental TPRs after accounting for various sources of errors. 14 refs., 6 figs., 4 tabs.

  7. Software Comparison

    NASA Technical Reports Server (NTRS)

    Blanchard, D. C.

    1986-01-01

    Software Comparison Package (SCP) compares similar files. Normally, these are 90-character files produced by CDC UPDATE utility from program libraries that contain FORTRAN source code plus identifier. SCP also used to compare load maps, cross-reference outputs, and UPDATE corrections sets. Helps wherever line-by-line comparison of similarly structured files required.

  8. The Use of the Rolled-up Vortex Concept for Predicting Wing-tail Interference and Comparison with Experiment at Mach Number of 1.62 for a Series of Missile Configurations Having Tandem Cruciform Lifting Surfaces

    NASA Technical Reports Server (NTRS)

    Grigsby, Carl E

    1952-01-01

    The method for predicting wing- tail interference whereby the trailing vortex system behind lifting wings is replaced by fully rolled-up vortices has been applied to the calculation of tail efficiency parameters, lift characteristics, and center -of-pressure locations for a series of generalized missile configurations. The calculations have been carried out with assumed and experimental vortex locations, and comparisons made with experimental data. The measured spanwise locations of the vortices for the inline case were found to be in good agreement with the asymptotic values computed from the center of gravity of the vorticity using the method of Lagerstrom and Graham. For the interdigitated configurations the measured spanwise locations were in only fair agreement with the asymptotic locations computed for the inline case. The vertical displacement of the vortices with angle of attack for both inline and interdigitated configurations was small. The method utilizing the rolled -up vortex concept was shown to give good results in the prediction of tail efficiency variations with angle of attack for inline configurations. Not as good correlation with experiment was shown for the interdigitated configurations. Complete configuration lift -curve slopes and center -of-pressure locations, obtained using t ail efficiency calculations together with the characteristics of the components obtained from available theoretical methods, showed excellent correlation with experimental results.

  9. Absolute cross sections with polarization effects in Ne{sup {asterisk}}(2p{sup 5}3p)+He collisions: A detailed comparison between theory and experiment

    SciTech Connect

    Bahrim, C. |; Kucal, H.; Masnou-Seeuws, F.

    1997-08-01

    Quantal calculations are presented for intramultiplet mixing collisions of Ne{sup {asterisk}}(2p{sup 5}3p) with He({sup 1}S{sub 0}) in the 60{endash}1250 meV collision energy range. The coupled equations are solved in a diabatic representation where the coupling terms are obtained using the model potential calculations of Hennecart and Masnou-Seeuws [J. Phys. B {bold 18}, 657 (1985)] for the interaction of the Ne{sup {asterisk}} outer electron with the two cores and values fitted on the spectroscopic data of Dabrowski and Herzberg [Mol. Spectrosc. {bold 73}, 183 (1978)] for the core-core interaction. An extensive comparison with the experimental data of the Eindhoven group is presented for absolute polarized cross sections and anisotropy parameters. Very good agreement is obtained with thermal energy data of Manders {ital et al.} [Phys. Rev. A {bold 39}, 4467 (1989)], while the systematic 30{endash}40{percent} discrepancy with superthermal data of Boom {ital et al.} [Phys. Rev. A {bold 49}, 4660 (1994)] might be attributed to a calibration problem in the experiment rather than to an inaccuracy in the long-range potentials. {copyright} {ital 1997} {ital The American Physical Society}

  10. Rubber friction: comparison of theory with experiment.

    PubMed

    Lorenz, B; Persson, B N J; Dieluweit, S; Tada, T

    2011-12-01

    We have measured the friction force acting on a rubber block slid on a concrete surface. We used both unfilled and filled (with carbon black) styrene butadiene (SB) rubber and have varied the temperature from -10 °C to 100 °C and the sliding velocity from 1 μm/s to 1000 μm/s. We find that the experimental data at different temperatures can be shifted into a smooth master-curve, using the temperature-frequency shifting factors obtained from measurements of the bulk viscoelastic modulus. The experimental data has been analyzed using a theory which takes into account the contributions to the friction from both the substrate asperity-induced viscoelastic deformations of the rubber, and from shearing the area of real contact. For filled SB rubber the frictional shear stress σ(f) in the area of real contact results mainly from the energy dissipation at the opening crack on the exit side of the rubber-asperity contact regions. For unfilled rubber we instead attribute σ(f) to shearing of a thin rubber smear film, which is deposited on the concrete surface during run in. We observe very different rubber wear processes for filled and unfilled SB rubber, which is consistent with the different frictional processes. Thus, the wear of filled SB rubber results in micrometer-sized rubber particles which accumulate as dry dust, which is easily removed by blowing air on the concrete surface. This wear process seams to occur at a steady rate. For unfilled rubber a smear film forms on the concrete surface, which cannot be removed even using a high-pressure air stream. In this case the wear rate appears to slow down after some run in time period.

  11. Cross Section Calculations and Comparison to Experiment

    NASA Technical Reports Server (NTRS)

    Townsend, L. W.; Ford, W. P.; Dewet, W. C.; Werneth, C. M.

    2016-01-01

    Understanding fragmentation of galactic cosmic ray nuclei in collisions within spacecraft structures and human tissues is an important element in assessing biological risk to crew members from this radiation source. Over the past four decades, various models have been developed to describe these important processes. Some models invoke semi-classical concepts based upon geometric descriptions of collisions between spherical nuclei.

  12. Comparison of EGS5 Simulations with Experiment

    SciTech Connect

    Nelson, W.Ralph; Field, Clive; /SLAC

    2006-12-01

    Simulations, made using EGS5, of the longitudinal and radial distributions of energy deposition of electrons of various energies are compared with experimental results in the literature. Energies and materials are: 1 GeV in water and aluminum; 6 GeV in aluminum, copper and lead; and (longitudinal only) 28.5 GeV in alumina (Al{sub 2}O{sub 3}). There is general agreement within a few percent over most of the shower profile. Substantial discrepancies are noted at depths far beyond shower maximum, reaching {approx}30-50% in the cases of lead and copper at 6 GeV.

  13. Experiments in Computing: A Survey

    PubMed Central

    Moisseinen, Nella

    2014-01-01

    Experiments play a central role in science. The role of experiments in computing is, however, unclear. Questions about the relevance of experiments in computing attracted little attention until the 1980s. As the discipline then saw a push towards experimental computer science, a variety of technically, theoretically, and empirically oriented views on experiments emerged. As a consequence of those debates, today's computing fields use experiments and experiment terminology in a variety of ways. This paper analyzes experimentation debates in computing. It presents five ways in which debaters have conceptualized experiments in computing: feasibility experiment, trial experiment, field experiment, comparison experiment, and controlled experiment. This paper has three aims: to clarify experiment terminology in computing; to contribute to disciplinary self-understanding of computing; and, due to computing's centrality in other fields, to promote understanding of experiments in modern science in general. PMID:24688404

  14. Risk comparison

    SciTech Connect

    Coppola, A.; Hall, R.E.

    1981-02-01

    This report presents data for the comparison of societal risk from natural and man-made hazards. Only fatalities resulting from the hazards are used in the comparison, with the data and the comparative analysis taken from current literature. In comparing societal risks for most of the hazards, both expected values and frequency vs consequence curves are presented. For a subset of hazards, notably the power generation technologies (nuclear, coal, oil, and gas), which have not exhibited high consequence events (catastrophes), the comparisons are based on estimated expected values only. Individual risk data are presented in two ways, a probability of death within a year and the amount of life shortening of an average life span. 27 refs., 21 figs., 25 tabs.

  15. A comparison of four receptor models used to quantify the boreal wildfire smoke contribution to surface PM2.5 in Halifax, Nova Scotia during the BORTAS-B experiment

    NASA Astrophysics Data System (ADS)

    Gibson, M. D.; Haelssig, J.; Pierce, J. R.; Parrington, M.; Franklin, J. E.; Hopper, J. T.; Li, Z.; Ward, T. J.

    2015-01-01

    This paper presents a quantitative comparison of the four most commonly used receptor models, namely absolute principal component scores (APCS), pragmatic mass closure (PMC), chemical mass balance (CMB) and positive matrix factorization (PMF). The models were used to predict the contributions of a wide variety of sources to PM2.5 mass in Halifax, Nova Scotia during the experiment to quantify the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites (BORTAS). However, particular emphasis was placed on the capacity of the models to predict the boreal wildfire smoke contributions during the BORTAS experiment. The performance of the four receptor models was assessed on their ability to predict the observed PM2.5 with an R2 close to 1, an intercept close to zero, a low bias and low RSME. Using PMF, a new woodsmoke enrichment factor of 52 was estimated for use in the PMC receptor model. The results indicate that the APCS and PMC receptor models were not able to accurately resolve total PM2.5 mass concentrations below 2 μg m-3. CMB was better able to resolve these low PM2.5 concentrations, but it could not be run on 9 of the 45 days of PM2.5 samples. PMF was found to be the most robust of the four models since it was able to resolve PM2.5 mass below 2 μg m-3, predict PM2.5 mass on all 45 days and utilise an unambiguous woodsmoke chemical tracer. The median woodsmoke relative contributions to PM2.5 estimated using PMC, APCS, CMB and PMF were found to be 0.08, 0.09, 3.59 and 0.14 μg m-3 respectively. The contribution predicted by the CMB model seemed to be clearly too high based on other observations. The use of levoglucosan as a tracer for woodsmoke was found to be vital for identifying this source.

  16. Long-term microparticle flux variability indicated by comparison of Interplanetary Dust Experiment (IDE) timed impacts for LDEF's first year in orbit with impact data for the entire 5.77-year orbital lifetime

    NASA Technical Reports Server (NTRS)

    Simon, Charles G.; Mulholland, J. Derral; Oliver, John P.; Cooke, William J.; Kassel, Philip C., Jr.

    1993-01-01

    The electronic sensors of the Interplanetary Dust Experiment (IDE) recorded precise impact times and approximate directions for submicron to approximately 100 micron size particles on all six primary sides of the spacecraft for the first 346 days of the LDEF orbital mission. Previously-reported analyses of the timed impact data have established their spatio-temporal features, including the demonstration that a preponderance of the particles in this regime are orbital debris and that a large fraction of the debris particles are encountered in megameter-size clouds. Short-term fluxes within such clouds can rise several orders of magnitude above the long-term average. These unexpectedly large short-term variations in debris flux raise the question of how representative an indication of the multi-year average flux is given by the nearly one year of timed data. One of the goals of the IDE was to conduct an optical survey of impact sites on detectors that remained active during the entire LDEF mission, to obtain full-mission fluxes. We present here the comparisons and contrasts among the new IDE optical survey impact data, the IDE first-year timed impact data, and impact data from other LDEF micrometeoroid and debris experiments. The following observations are reported: (1) the 5.77 year long-term integrated microparticle impact fluxes recorded by IDE detectors matched the integrated impact fluxes measured by other LDEF investigators for the same period; (2) IDE integrated microparticle impact fluxes varied by factors from 0.5 to 8.3 for LDEF days 1-346, 347-2106 and 1-2106 (5.77 years) on rows 3 (trailing edge, or West), 6 (South side), 12 (North side), and the Earth and Space ends; and (3) IDE integrated microparticle impact fluxes varied less than 3 percent for LDEF days 1-346, 347-2106 and 1-2106 (5.77 years) on row 9 (leading edge, or East). These results give further evidence of the accuracy and internal consistency of the recorded IDE impact data. This leads to

  17. Long-term particle flux variability indicated by comparison of Interplanetary Dust Experiment (IDE) timed impacts for LDEF's first year in orbit with impact data for the entire 5.75-year orbital lifetime

    NASA Technical Reports Server (NTRS)

    Mulholland, J. Derral; Simon, Charles G.; Cooke, William J.; Oliver, John P.; Misra, V.

    1992-01-01

    The electronic sensors of the Interplanetary Dust Experiment (IDE) recorded precise impact times and approximate directions for submicron to approximately 100-micron size particles on all six primary sides of the spacecraft for the first 346 days of the Long Duration Exposure Facility (LDEF) orbital mission. Previously-reported analyses of the timed impact data have established their spatio-temporal features, including the demonstration that a preponderance of the particles in this regime are orbital debris and that a large fraction of the debris particles are encountered as megameter-size clouds, some of which persist for long times. Short-term fluxes within such clouds can rise several orders of magnitude above the long-term average. These finding are consistent with the results of the first catastrophic hypervelocity laboratory impacts on a real satellite, recently reported in the press. Analysis continues on the geometric and evolutionary characteristics of these clouds, as well as on the isolation and characterization of the natural micrometeoroid component in the IDE data, but the unexpectedly large short-term variations in debris flux raises the question of how representative an indication of the multi-year average flux is given by the nearly one year of timed data. It has, therefore, always been one of the goals of IDE to conduct an optical survey of the craters on the IDE detectors, to obtain full-mission fluxes for comparisons with the timed data. This work is underway, and the results presently in hand are significant. Optical scanning of the ram and wake (East and West) panels is complete, and it is clear that the first year was in some respects not representative of the subsequent years. The 5.75-year average flux on East panel was 90 percent of the value predicted by the average flux recorded during the first year, while it was only 34 percent on West panel. This suggests that western hemisphere spacecraft launches are a major contributor to the long

  18. A comparison of five benchmarks

    NASA Technical Reports Server (NTRS)

    Huss, Janice E.; Pennline, James A.

    1987-01-01

    Five benchmark programs were obtained and run on the NASA Lewis CRAY X-MP/24. A comparison was made between the programs codes and between the methods for calculating performance figures. Several multitasking jobs were run to gain experience in how parallel performance is measured.

  19. Comparisons of cloud ice mass content retrieved from the radar-infrared radiometer method with aircraft data during the second international satellite cloud climatology project regional experiment (FIRE-II)

    SciTech Connect

    Matrosov, S.Y. |; Heymsfield, A.J.; Kropfli, R.A.; Snider, J.B.

    1996-04-01

    Comparisons of remotely sensed meteorological parameters with in situ direct measurements always present a challenge. Matching sampling volumes is one of the main problems for such comparisons. Aircraft usually collect data when flying along a horizontal leg at a speed of about 100 m/sec (or even greater). The usual sampling time of 5 seconds provides an average horizontal resolution of the order of 500 m. Estimations of vertical profiles of cloud microphysical parameters from aircraft measurements are hampered by sampling a cloud at various altitudes at different times. This paper describes the accuracy of aircraft horizontal and vertical coordinates relative to the location of the ground-based instruments.

  20. [Are clinical features derived from evidences and experiences outside of Japan applicable to clinical practices in Japan? Comparisons of results among studies conducted in US, Europe, Asian Countries and Japan].

    PubMed

    Kamada, Kyousuke

    2011-03-01

    Levetiracetam is an antiepileptic drug (AED) approved for the adjunctive treatment of partial seizures firstly in the US in 1999. In Japan, levetiracetam was approved for the adjunctive treatment of partial seizures. Accumulated evidences and experiences in US, Europe and Asian counties have indicated clinical features of levetiracetam (i.e., rapid onset of action, high efficacy and tolerability, no drug-drug interactions). One may ask whether the known clinical features are applicable to Japanese epilepsy patients with partial seizures. This article is aimed at answering such questions by reviewing published articles on effects of races onto pharmacokinetics and on efficacy and safety profiles shown in studies conducted in the US, Europe, Taiwan, China, Korea, Asian 6 countries and Japan, which allowed to compare the profiles across the different populations. Pharmacokinetic profiles were not different between Western and Japanese, and between Chinese and Western populations. The values of efficacy variables such as percentage (%) reduction of seizure frequency from baselines, 50% responder rate and seizure free rate at dose range of 1,000 mg-3,000 mg/d were similar across 4 open studies (Korea, 6 Asian countries, US, Europe and other western; % reduction: 43.2-52.3%, 50% responder rate: 43.6-57.9%, Seizure free rate: 16.2-20.2%). In the 6 placebo-controlled double blind studies (US, 2 Europe studies, China, Taiwan and Japan), the values of the efficacy variables of the levetiracetam arms (1,000 mg/d, 2,000 mg/d, 3,000 mg/d, 1,000-2,000 mg/d, 2,000-3,000 mg/d) were at least numerically superior to those of corresponding placebo arms even though the statistical significance was not obtained for all of the variables. The degrees of difference between the values of placebo and levetiracetam arms were within comparable ranges. These comparisons suggested levetiracetam would have similar efficacy and safety profiles in Japanese patients to those in the US, Europe, and