The use of fractional order derivatives for eddy current non-destructive testing

NASA Astrophysics Data System (ADS)

Sikora, Ryszard; Grzywacz, Bogdan; Chady, Tomasz

2018-04-01

The paper presents the possibility of using the fractional derivatives for non-destructive testing when a multi-frequency method based on eddy current is applied. It is shown that frequency characteristics obtained during tests can be approximated by characteristics of a proposed model in the form of fractional order transfer function, and values of parameters of this model can be utilized for detection and identification of defects.

Solar Sail Models and Test Measurements Correspondence for Validation Requirements Definition

NASA Technical Reports Server (NTRS)

Ewing, Anthony; Adams, Charles

2004-01-01

Solar sails are being developed as a mission-enabling technology in support of future NASA science missions. Current efforts have advanced solar sail technology sufficient to justify a flight validation program. A primary objective of this activity is to test and validate solar sail models that are currently under development so that they may be used with confidence in future science mission development (e.g., scalable to larger sails). Both system and model validation requirements must be defined early in the program to guide design cycles and to ensure that relevant and sufficient test data will be obtained to conduct model validation to the level required. A process of model identification, model input/output documentation, model sensitivity analyses, and test measurement correspondence is required so that decisions can be made to satisfy validation requirements within program constraints.

Students’ mental model in electric current

NASA Astrophysics Data System (ADS)

Pramesti, Y. S.; Setyowidodo, I.

2018-05-01

Electricity is one of essential topic in learning physics. This topic was studied in elementary until university level. Although electricity was related to our daily activities, but it doesn’t ensure that students have the correct concept. The aim of this research was to investigate and then categorized the students’ mental model. Subject consisted of 59 students of mechanical engineering that studied Physics for Engineering. This study was used a qualitative approach that used in this research is phenomenology. Data were analyzed qualitatively by using pre-test, post-test, and investigation for discovering further information. Three models were reported, showing a pattern which related to individual way of thinking about electric current. The mental model that was discovered in this research are: 1) electric current as a flow; 2) electric current as a source of energy, 3) electric current as a moving charge.

40 CFR 80.49 - Fuels to be used in augmenting the complex emission model through vehicle testing.

Code of Federal Regulations, 2014 CFR

2014-07-01

... complex emission model through vehicle testing. 80.49 Section 80.49 Protection of Environment... Reformulated Gasoline § 80.49 Fuels to be used in augmenting the complex emission model through vehicle testing... augmenting the complex emission model with a parameter not currently included in the complex emission model...

40 CFR 80.49 - Fuels to be used in augmenting the complex emission model through vehicle testing.

Code of Federal Regulations, 2013 CFR

2013-07-01

... complex emission model through vehicle testing. 80.49 Section 80.49 Protection of Environment... Reformulated Gasoline § 80.49 Fuels to be used in augmenting the complex emission model through vehicle testing... augmenting the complex emission model with a parameter not currently included in the complex emission model...

40 CFR 80.49 - Fuels to be used in augmenting the complex emission model through vehicle testing.

Code of Federal Regulations, 2011 CFR

2011-07-01

... complex emission model through vehicle testing. 80.49 Section 80.49 Protection of Environment... Reformulated Gasoline § 80.49 Fuels to be used in augmenting the complex emission model through vehicle testing... augmenting the complex emission model with a parameter not currently included in the complex emission model...

40 CFR 80.49 - Fuels to be used in augmenting the complex emission model through vehicle testing.

Code of Federal Regulations, 2012 CFR

2012-07-01

... complex emission model through vehicle testing. 80.49 Section 80.49 Protection of Environment... Reformulated Gasoline § 80.49 Fuels to be used in augmenting the complex emission model through vehicle testing... augmenting the complex emission model with a parameter not currently included in the complex emission model...

Instrumentation and telemetry systems for free-flight drop model testing

NASA Technical Reports Server (NTRS)

Hyde, Charles R.; Massie, Jeffrey J.

1993-01-01

This paper presents instrumentation and telemetry system techniques used in free-flight research drop model testing at the NASA Langley Research Center. The free-flight drop model test technique is used to conduct flight dynamics research of high performance aircraft using dynamically scaled models. The free-flight drop model flight testing supplements research using computer analysis and wind tunnel testing. The drop models are scaled to approximately 20 percent of the size of the actual aircraft. This paper presents an introduction to the Free-Flight Drop Model Program which is followed by a description of the current instrumentation and telemetry systems used at the NASA Langley Research Center, Plum Tree Test Site. The paper describes three telemetry downlinks used to acquire the data, video, and radar tracking information from the model. Also described are two telemetry uplinks, one used to fly the model employing a ground-based flight control computer and a second to activate commands for visual tracking and parachute recovery of the model. The paper concludes with a discussion of free-flight drop model instrumentation and telemetry system development currently in progress for future drop model projects at the NASA Langley Research Center.

Effect of Polya Problem-Solving Model on Senior Secondary School Students' Performance in Current Electricity

ERIC Educational Resources Information Center

Olaniyan, Ademola Olatide; Omosewo, Esther O.; Nwankwo, Levi I.

2015-01-01

This study was designed to investigate the Effect of Polya Problem-Solving Model on Senior School Students' Performance in Current Electricity. It was a quasi experimental study of non- randomized, non equivalent pre-test post-test control group design. Three research questions were answered and corresponding three research hypotheses were tested…

Modeling of Nonacoustic Combustion Instability in Simulations of Hybrid Motor Tests

NASA Technical Reports Server (NTRS)

Rocker, M.

2000-01-01

A transient model of a hybrid motor was formulated to study the cause and elimination of nonacoustic combustion instability. The transient model was used to simulate four key tests out of a series of seventeen hybrid motor tests conducted by Thiokol, Rocketdyne, and Martin Marietta at NASA Marshall Space Flight Center (MSFC). These tests were performed under the Hybrid Propulsion Technology for Launch Vehicle Boosters (HPTLVB) program. The first test resulted in stable combustion. The second test resulted in large-amplitude, 6.5-Hz chamber pressure oscillations that gradually damped away by the end of the test. The third test resulted in large-amplitude, 7.5-Hz chamber pressure oscillations that were sustained throughout the test. The seventh test resulted in elimination of combustion instability with the installation of an orifice immediately upstream of the injector. Formulation and implementation of the model are the scope of this presentation. The current model is an independent continuation of modeling presented previously by joint Thiokol-Rocketdyne collaborators Boardman, Hawkins, Wassom. and Claflin. The previous model simulated an unstable independent research and development (IR&D) hybrid motor test performed by Thiokol. There was very good agreement between the model and test data. Like the previous model, the current model was developed using Matrix-x simulation software. However, tests performed at MSFC under the HPTLVB program were actually simulated. ln the current model, the hybrid motor, consisting of the liquid oxygen (lox) injector, the multiport solid fuel grain, and nozzle, was simulated. The lox feedsystem, consisting of the tank, venturi. valve, and feed lines, was also simulated in the model. All components of the hybrid motor and lox feedsystem are treated by a lumped-parameter approach. Agreement between the results of the transient model and actual test data was very good. This agreement between simulated and actual test data indicated that the combustion instability in the hybrid motor was due to two causes: 1. a lox feed system of insufficient stiffness, and 2. a lox injector with an impedance (it pressure drop that was too low to provide damping against the feed system oscillations. Also, it was discovered that testing with a new grain of solid fuel sustained the combustion instability. However, testing with a used grain of solid fuel caused the combustion instability to gradually decay.

Impact and cost-effectiveness of chlamydia testing in Scotland: a mathematical modelling study.

PubMed

Looker, Katharine J; Wallace, Lesley A; Turner, Katherine M E

2015-01-15

Chlamydia is the most common sexually transmitted bacterial infection in Scotland, and is associated with potentially serious reproductive outcomes, including pelvic inflammatory disease (PID) and tubal factor infertility (TFI) in women. Chlamydia testing in Scotland is currently targeted towards symptomatic individuals, individuals at high risk of existing undetected infection, and young people. The cost-effectiveness of testing and treatment to prevent PID and TFI in Scotland is uncertain. A compartmental deterministic dynamic model of chlamydia infection in 15-24 year olds in Scotland was developed. The model was used to estimate the impact of a change in testing strategy from baseline (16.8% overall testing coverage; 0.4 partners notified and tested/treated per treated positive index) on PID and TFI cases. Cost-effectiveness calculations informed by best-available estimates of the quality-adjusted life years (QALYs) lost due to PID and TFI were also performed. Increasing overall testing coverage by 50% from baseline to 25.2% is estimated to result in 21% fewer cases in young women each year (PID: 703 fewer; TFI: 88 fewer). A 50% decrease to 8.4% would result in 20% more PID (669 additional) and TFI (84 additional) cases occurring annually. The cost per QALY gained of current testing activities compared to no testing is £40,034, which is above the £20,000-£30,000 cost-effectiveness threshold. However, calculations are hampered by lack of reliable data. Any increase in partner notification from baseline would be cost-effective (incremental cost per QALY gained for a partner notification efficacy of 1 compared to baseline: £5,119), and would increase the cost-effectiveness of current testing strategy compared to no testing, with threshold cost-effectiveness reached at a partner notification efficacy of 1.5. However, there is uncertainty in the extent to which partner notification is currently done, and hence the amount by which it could potentially be increased. Current chlamydia testing strategy in Scotland is not cost-effective under the conservative model assumptions applied. However, with better data enabling some of these assumptions to be relaxed, current coverage could be cost-effective. Meanwhile, increasing partner notification efficacy on its own would be a cost-effective way of preventing PID and TFI from current strategy.

Tow Tank Dynamic Test Rig Drawings and Bill of Materials for the Aquantis 2.5 MW Ocean Current Generation Device

DOE Data Explorer

Swales, Henry; Banko, Richard; Coakley, David

2015-06-03

Aquantis 2.5 MW Ocean Current Generation Device, Tow Tank Dynamic Test Rig Drawings and Bill of Materials. This submission contains information on the equipment for the scaled model tow tank testing. The information includes hardware, test protocols, and plans.

A mobile test facility based on a magnetic cumulative generator to study the stability of the power plants under impact of lightning currents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shurupov, A. V.; Zavalova, V. E., E-mail: zavalova@fites.ru; Kozlov, A. V.

The report presents the results of the development and field testing of a mobile test facility based on a helical magnetic cumulative generator (MCGTF). The system is designed for full-scale modeling of lightning currents to study the safety of power plants of any type, including nuclear power plants. Advanced technologies of high-energy physics for solving both engineering and applied problems underlie this pilot project. The energy from the magnetic cumulative generator (MCG) is transferred to a high-impedance load with high efficiency of more than 50% using pulse transformer coupling. Modeling of the dynamics of the MEG that operates in amore » circuit with lumped parameters allows one to apply the law of inductance output during operation of the MCG, thus providing the required front of the current pulse in the load without using any switches. The results of field testing of the MCGTF are presented for both the ground loop and the model load. The ground loop generates a load resistance of 2–4 Ω. In the tests, the ohmic resistance of the model load is 10 Ω. It is shown that the current pulse parameters recorded in the resistive-inductive load are close to the calculated values.« less

Adaptive Testing without IRT.

ERIC Educational Resources Information Center

Yan, Duanli; Lewis, Charles; Stocking, Martha

It is unrealistic to suppose that standard item response theory (IRT) models will be appropriate for all new and currently considered computer-based tests. In addition to developing new models, researchers will need to give some attention to the possibility of constructing and analyzing new tests without the aid of strong models. Computerized…

Physics and technology in the ion-cyclotron range of frequency on Tore Supra and TITAN test facility: implication for ITER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Litaudon, X; Bernard, J. M.; Colas, L.

2013-01-01

To support the design of an ITER ion-cyclotron range of frequency heating (ICRH) system and to mitigate risks of operation in ITER, CEA has initiated an ambitious Research & Development program accompanied by experiments on Tore Supra or test-bed facility together with a significant modelling effort. The paper summarizes the recent results in the following areas: Comprehensive characterization (experiments and modelling) of a new Faraday screen concept tested on the Tore Supra antenna. A new model is developed for calculating the ICRH sheath rectification at the antenna vicinity. The model is applied to calculate the local heat flux on Toremore » Supra and ITER ICRH antennas. Full-wave modelling of ITER ICRH heating and current drive scenarios with the EVE code. With 20 MW of power, a current of 400 kA could be driven on axis in the DT scenario. Comparison between DT and DT(3He) scenario is given for heating and current drive efficiencies. First operation of CW test-bed facility, TITAN, designed for ITER ICRH components testing and could host up to a quarter of an ITER antenna. R&D of high permittivity materials to improve load of test facilities to better simulate ITER plasma antenna loading conditions.« less

Simulation of Non-Acoustic Combustion Instability in a Hybrid Rocket Motor

NASA Technical Reports Server (NTRS)

Rocker, Marvin

1999-01-01

A transient model of a hybrid motor was formulated to study the cause and elimination of non-acoustic combustion instability. The transient model was used to simulate four key tests out of a series of seventeen hybrid motor tests conducted by Thiokol, Rocketdyne and Martin Marietta at NASA/Marshall Space Flight Center (NASAIMSFC). These tests were performed under the Hybrid Propulsion Technology for Launch Vehicle Boosters (HPTLVB) program. The first test resulted in stable combustion. The second test resulted in large-amplitude, 6.5 Hz chamber pressure oscillations that gradually damped away by the end of the test. The third test resulted in large-amplitude, 7.5 Hz chamber pressure oscillations that were sustained throughout the test. The seventh test resulted in the elimination of combustion instability with the installation of an orifice immediately upstream of the injector. The formulation and implementation of the model are the scope of this presentation. The current model is an independent continuation of modeling presented previously by joint Thiokol-Rocketdyne collaborators Boardman, Hawkins, Wassom, and Claflin. The previous model simulated an unstable IR&D hybrid motor test performed by Thiokol. There was very good agreement between the model and the test data. Like the previous model, the current model was developed using Matrix-x simulation software. However, the tests performed at NASA/MSFC under the HPTLVB program were actually simulated. In the current model, the hybrid motor consisting of the liquid oxygen (LOX) injector, the multi-port solid fuel grain and the nozzle was simulated. Also, simulated in the model was the LOX feed system consisting of the tank, venturi, valve and feed lines. All components of the hybrid motor and LOX feed system are treated by a lumped-parameter approach. Agreement between the results of the transient model and the actual test data was very good. This agreement between simulated and actual test data indicated that the combustion instability in the hybrid motor was due to two causes. The first cause was a LOX feed system of insufficient stiffness. The second cause was a LOX injector with an impedance or pressure drop that was too low to provide damping against the feed system oscillations. Also, it was discovered that testing with a new grain of solid fuel sustained the combustion instability. However, testing with a used grain of solid fuel caused the combustion instability to gradually decay.

Simulation of Non-Acoustic Combustion Instability in a Hybrid Rocket Motor

NASA Technical Reports Server (NTRS)

Rocker, Marvin

1999-01-01

A transient model of a hybrid motor was formulated to study the cause and elimination of non-acoustic combustion instability. The transient model was used to simulate four key tests out of a series of seventeen hybrid motor tests conducted by Thiokol, Rocketdyne and Martin Marietta at NASA/Marshall Space Flight Center (NASA/MSFC). These tests were performed under the Hybrid Propulsion Technology for Launch Vehicle Boosters (HPTLVB) program. The first test resulted in stable combustion. The second test resulted in large-amplitude, 6.5 Hz chamber pressure oscillations that gradually damped away by the end of the test. The third test resulted in large-amplitude, 7.5 Hz chamber pressure oscillations that were sustained throughout the test. The seventh test resulted in the elimination of combustion instability with the installation of an orifice immediately upstream of the injector. The formulation and implementation of the model are the scope of this presentation. The current model is an independent continuation of modeling presented previously by joint Thiokol-Rocketdyne collaborators Boardman, Hawkins, Wassom, and Claflin. The previous model simulated an unstable IR&D hybrid motor test performed by Thiokol. There was very good agreement between the model and the test data. Like the previous model, the current model was developed using Matrix-x simulation software. However, the tests performed at NASA/MSFC under the HPTLVB program were actually simulated. In the current model, the hybrid motor consisting of the liquid oxygen (LOX) injector, the multi-port solid fuel grain and the nozzle was simulated. Also, simulated in the model was the LOX feed system consisting of the tank, venturi, valve and feed lines. All components of the hybrid motor and LOX feed system are treated by a lumped-parameter approach. Agreement between the results of the transient model and the actual test data was very good. This agreement between simulated and actual test data indicated that the combustion instability in the hybrid motor was due to two causes. The first cause was a LOX feed system of insufficient stiffness. The second cause was a LOX injector with an impedance or pressure drop that was too low to provide damping against the feed system oscillations. Also, it was discovered that testing with a new grain of solid fuel sustained the combustion instability. However, testing with a used grain of solid fuel caused the combustion instability to gradually decay.

Operational prediction of rip currents using numerical model and nearshore bathymetry from video images

NASA Astrophysics Data System (ADS)

Sembiring, L.; Van Ormondt, M.; Van Dongeren, A. R.; Roelvink, J. A.

2017-07-01

Rip currents are one of the most dangerous coastal hazards for swimmers. In order to minimize the risk, a coastal operational-process based-model system can be utilized in order to provide forecast of nearshore waves and currents that may endanger beach goers. In this paper, an operational model for rip current prediction by utilizing nearshore bathymetry obtained from video image technique is demonstrated. For the nearshore scale model, XBeach1 is used with which tidal currents, wave induced currents (including the effect of the wave groups) can be simulated simultaneously. Up-to-date bathymetry will be obtained using video images technique, cBathy 2. The system will be tested for the Egmond aan Zee beach, located in the northern part of the Dutch coastline. This paper will test the applicability of bathymetry obtained from video technique to be used as input for the numerical modelling system by comparing simulation results using surveyed bathymetry and model results using video bathymetry. Results show that the video technique is able to produce bathymetry converging towards the ground truth observations. This bathymetry validation will be followed by an example of operational forecasting type of simulation on predicting rip currents. Rip currents flow fields simulated over measured and modeled bathymetries are compared in order to assess the performance of the proposed forecast system.

Crash Certification by Analysis - Are We There Yet?

NASA Technical Reports Server (NTRS)

Jackson, Karen E.; Fasanella, Edwin L.; Lyle, Karen H.

2006-01-01

This paper addresses the issue of crash certification by analysis. This broad topic encompasses many ancillary issues including model validation procedures, uncertainty in test data and analysis models, probabilistic techniques for test-analysis correlation, verification of the mathematical formulation, and establishment of appropriate qualification requirements. This paper will focus on certification requirements for crashworthiness of military helicopters; capabilities of the current analysis codes used for crash modeling and simulation, including some examples of simulations from the literature to illustrate the current approach to model validation; and future directions needed to achieve "crash certification by analysis."

Upgrades, Current Capabilities and Near-Term Plans of the NASA ARC Mars Climate

NASA Technical Reports Server (NTRS)

Hollingsworth, J. L.; Kahre, Melinda April; Haberle, Robert M.; Schaeffer, James R.

2012-01-01

We describe and review recent upgrades to the ARC Mars climate modeling framework, in particular, with regards to physical parameterizations (i.e., testing, implementation, modularization and documentation); the current climate modeling capabilities; selected research topics regarding current/past climates; and then, our near-term plans related to the NASA ARC Mars general circulation modeling (GCM) project.

Suicide risk factors for young adults: testing a model across ethnicities.

PubMed

Gutierrez, P M; Rodriguez, P J; Garcia, P

2001-06-01

A general path model based on existing suicide risk research was developed to test factors contributing to current suicidal ideation in young adults. A sample of 673 undergraduate students completed a packet of questionnaires containing the Beck Depression Inventory, Adult Suicidal Ideation Questionnaire, and Multi-Attitude Suicide Tendency Scale. They also provided information on history of suicidality and exposure to attempted and completed suicide in others. Structural equation modeling was used to test the fit of the data to the hypothesized model. Goodness-of-fit indices were adequate and supported the interactive effects of exposure, repulsion by life, depression, and history of self-harm on current ideation. Model fit for three subgroups based on race/ethnicity (i.e., White, Black, and Hispanic) determined that repulsion by life and depression function differently across groups. Implications of these findings for current methods of suicide risk assessment and future research are discussed in the context of the importance of culture.

10 CFR Appendix A to Subpart K of... - Uniform Test Method for Measuring the Energy Consumption of Distribution Transformers

Code of Federal Regulations, 2014 CFR

2014-01-01

... Uniform Test Method is used to test more than one unit of a basic model to determine the efficiency of... one ampere and the test current is limited to 15 percent of the winding current. Connect the... 10 Energy 3 2014-01-01 2014-01-01 false Uniform Test Method for Measuring the Energy Consumption...

Welding current and melting rate in GMAW of aluminium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pandey, S.; Rao, U.R.K.; Aghakhani, M.

1996-12-31

Studies on GMAW of aluminium and its alloy 5083, revealed that the welding current and melting rate were affected by any change in wire feed rate, arc voltage, nozzle to plate distance, welding speed and torch angle. Empirical models have been presented to determine accurately the welding current and melting rate for any set of these parameters. These results can be utilized for determining accurately the heat input into the workpiece from which reliable predictions can be made about the mechanical and the metallurgical properties of a welded joint. The analysis of the model also helps in providing a vitalmore » information about the static V-I characteristics of the welding power source. The models were developed using a two-level fractional factorial design. The adequacy of the model was tested by the use of analysis of variance technique and the significance of the coefficients was tested by the student`s t test. The estimated and observed values of the welding current and melting rate have been shown on a scatter diagram and the interaction effects of different parameters involved have been presented in graphical forms.« less

Goodness-Of-Fit Test for Nonparametric Regression Models: Smoothing Spline ANOVA Models as Example.

PubMed

Teran Hidalgo, Sebastian J; Wu, Michael C; Engel, Stephanie M; Kosorok, Michael R

2018-06-01

Nonparametric regression models do not require the specification of the functional form between the outcome and the covariates. Despite their popularity, the amount of diagnostic statistics, in comparison to their parametric counter-parts, is small. We propose a goodness-of-fit test for nonparametric regression models with linear smoother form. In particular, we apply this testing framework to smoothing spline ANOVA models. The test can consider two sources of lack-of-fit: whether covariates that are not currently in the model need to be included, and whether the current model fits the data well. The proposed method derives estimated residuals from the model. Then, statistical dependence is assessed between the estimated residuals and the covariates using the HSIC. If dependence exists, the model does not capture all the variability in the outcome associated with the covariates, otherwise the model fits the data well. The bootstrap is used to obtain p-values. Application of the method is demonstrated with a neonatal mental development data analysis. We demonstrate correct type I error as well as power performance through simulations.

Using Multigroup Confirmatory Factor Analysis to Test Measurement Invariance in Raters: A Clinical Skills Examination Application

ERIC Educational Resources Information Center

Kahraman, Nilufer; Brown, Crystal B.

2015-01-01

Psychometric models based on structural equation modeling framework are commonly used in many multiple-choice test settings to assess measurement invariance of test items across examinee subpopulations. The premise of the current article is that they may also be useful in the context of performance assessment tests to test measurement invariance…

The price of performance: a cost and performance analysis of the implementation of cell-free fetal DNA testing for Down syndrome in Ontario, Canada.

PubMed

Okun, N; Teitelbaum, M; Huang, T; Dewa, C S; Hoch, J S

2014-04-01

To examine the cost and performance implications of introducing cell-free fetal DNA (cffDNA) testing within modeled scenarios in a publicly funded Canadian provincial Down syndrome (DS) prenatal screening program. Two clinical algorithms were created: the first to represent the current screening program and the second to represent one that incorporates cffDNA testing. From these algorithms, eight distinct scenarios were modeled to examine: (1) the current program (no cffDNA), (2) the current program with first trimester screening (FTS) as the nuchal translucency-based primary screen (no cffDNA), (3) a program substituting current screening with primary cffDNA, (4) contingent cffDNA with current FTS performance, (5) contingent cffDNA at a fixed price to result in overall cost neutrality,(6) contingent cffDNA with an improved detection rate (DR) of FTS, (7) contingent cffDNA with higher uptake of FTS, and (8) contingent cffDNA with optimized FTS (higher uptake and improved DR). This modeling study demonstrates that introducing contingent cffDNA testing improves performance by increasing the number of cases of DS detected prenatally, and reducing the number of amniocenteses performed and concomitant iatrogenic pregnancy loss of pregnancies not affected by DS. Costs are modestly increased, although the cost per case of DS detected is decreased with contingent cffDNA testing. Contingent models of cffDNA testing can improve overall screening performance while maintaining the provision of an 11- to 13-week scan. Costs are modestly increased, but cost per prenatally detected case of DS is decreased. © 2013 John Wiley & Sons, Ltd.

Status of MSBS Study at NAL in 1995

NASA Technical Reports Server (NTRS)

Sawada, Hideo; Suenaga, Hisasi; Kunimasu, Tetuya; Kohno, Takashi

1996-01-01

Magnetic field intensity and currents passing through the coils of the National Aerospace Laboratory (NAL) 1O cm Magnetic Suspension and Balance System (MSBS) were measured while a cylindrical model was oscillated along x,y,z and also about y and z axes, respectively. The model was made of alnico 5 and was 8 mm in diameter and 60 mm long. Two kinds of tests were carried out. Amplitude of the oscillation was varied at a frequency of 10 Hz. Frequency was varied from 1 to 50 Hz in the other test. Results of the tests show that the relation between coil currents and magnetic force acting on the model is affected by frequency. They also show that the relation between measured magnetic field intensity and the force in vertical direction is independent of the frequency below 30 Hz. Using the measured magnetic field intensity, the vertical force can be evaluated at the MSBS instantaneously when a model moves at frequencies below 30 Hz. A static drag force calibration test was carried out at the 60 cm MSBS. Obtained relationships between measured drag coil currents and loads shows large hysteresis.

Design of Bi-Directional Hydrofoils for Tidal Current Turbines

NASA Astrophysics Data System (ADS)

Nedyalkov, Ivaylo; Wosnik, Martin

2015-11-01

Tidal Current Turbines operate in flows which reverse direction. Bi-directional hydrofoils have rotational symmetry and allow such turbines to operate without the need for pitch or yaw control, decreasing the initial and maintenance costs. A numerical test-bed was developed to automate the simulations of hydrofoils in OpenFOAM and was utilized to simulate the flow over eleven classes of hydrofoils comprising a total of 700 foil shapes at different angles of attack. For promising candidate foil shapes physical models of 75 mm chord and 150 mm span were fabricated and tested in the University of New Hampshire High-Speed Cavitation Tunnel (HiCaT). The experimental results were compared to the simulations for model validation. The numerical test-bed successfully generated simulations for a wide range of foil shapes, although, as expected, the k - ω - SST turbulence model employed here was not adequate for some of the foils and for large angles of attack at which separation occurred. An optimization algorithm is currently being coupled with the numerical test-bed and additional turbulence models will be implemented in the future.

Detecting defects in marine structures by using eddy current infrared thermography.

PubMed

Swiderski, W

2016-12-01

Eddy current infrared (IR) thermography is a new nondestructive testing (NDT) technique used for the detection of cracks in electroconductive materials. By combining the well-established inspection methods of eddy current NDT and IR thermography, this technique uses induced eddy currents to heat test samples. In this way, IR thermography allows the visualization of eddy current distribution that is distorted in defect sites. This paper discusses the results of numerical modeling of eddy current IR thermography procedures in application to marine structures.

Animal models for dengue vaccine development and testing

PubMed Central

2017-01-01

Dengue fever is a tropical endemic disease; however, because of climate change, it may become a problem in South Korea in the near future. Research on vaccines for dengue fever and outbreak preparedness are currently insufficient. In addition, because there are no appropriate animal models, controversial results from vaccine efficacy assessments and clinical trials have been reported. Therefore, to study the mechanism of dengue fever and test the immunogenicity of vaccines, an appropriate animal model is urgently needed. In addition to mouse models, more suitable models using animals that can be humanized will need to be constructed. In this report, we look at the current status of model animal construction and discuss which models require further development. PMID:28775974

Animal models for dengue vaccine development and testing.

PubMed

Na, Woonsung; Yeom, Minjoo; Choi, Il-Kyu; Yook, Heejun; Song, Daesub

2017-07-01

Dengue fever is a tropical endemic disease; however, because of climate change, it may become a problem in South Korea in the near future. Research on vaccines for dengue fever and outbreak preparedness are currently insufficient. In addition, because there are no appropriate animal models, controversial results from vaccine efficacy assessments and clinical trials have been reported. Therefore, to study the mechanism of dengue fever and test the immunogenicity of vaccines, an appropriate animal model is urgently needed. In addition to mouse models, more suitable models using animals that can be humanized will need to be constructed. In this report, we look at the current status of model animal construction and discuss which models require further development.

Testing Mediation in Structural Equation Modeling: The Effectiveness of the Test of Joint Significance

ERIC Educational Resources Information Center

Leth-Steensen, Craig; Gallitto, Elena

2016-01-01

A large number of approaches have been proposed for estimating and testing the significance of indirect effects in mediation models. In this study, four sets of Monte Carlo simulations involving full latent variable structural equation models were run in order to contrast the effectiveness of the currently popular bias-corrected bootstrapping…

Non-animal models of epithelial barriers (skin, intestine and lung) in research, industrial applications and regulatory toxicology.

PubMed

Gordon, Sarah; Daneshian, Mardas; Bouwstra, Joke; Caloni, Francesca; Constant, Samuel; Davies, Donna E; Dandekar, Gudrun; Guzman, Carlos A; Fabian, Eric; Haltner, Eleonore; Hartung, Thomas; Hasiwa, Nina; Hayden, Patrick; Kandarova, Helena; Khare, Sangeeta; Krug, Harald F; Kneuer, Carsten; Leist, Marcel; Lian, Guoping; Marx, Uwe; Metzger, Marco; Ott, Katharina; Prieto, Pilar; Roberts, Michael S; Roggen, Erwin L; Tralau, Tewes; van den Braak, Claudia; Walles, Heike; Lehr, Claus-Michael

2015-01-01

Models of the outer epithelia of the human body - namely the skin, the intestine and the lung - have found valid applications in both research and industrial settings as attractive alternatives to animal testing. A variety of approaches to model these barriers are currently employed in such fields, ranging from the utilization of ex vivo tissue to reconstructed in vitro models, and further to chip-based technologies, synthetic membrane systems and, of increasing current interest, in silico modeling approaches. An international group of experts in the field of epithelial barriers was convened from academia, industry and regulatory bodies to present both the current state of the art of non-animal models of the skin, intestinal and pulmonary barriers in their various fields of application, and to discuss research-based, industry-driven and regulatory-relevant future directions for both the development of new models and the refinement of existing test methods. Issues of model relevance and preference, validation and standardization, acceptance, and the need for simplicity versus complexity were focal themes of the discussions. The outcomes of workshop presentations and discussions, in relation to both current status and future directions in the utilization and development of epithelial barrier models, are presented by the attending experts in the current report.

Investigation of the effects of external current systems on the MAGSAT data utilizing grid cell modeling techniques

NASA Technical Reports Server (NTRS)

Klumpar, D. M. (Principal Investigator)

1982-01-01

Efforts in support of the development of a model of the magnetic fields due to ionospheric and magnetospheric electrical currents are discussed. Specifically, progress made in reading MAGSAT tapes and plotting the deviation of the measured magnetic field components with respect to a spherical harmonic model of the main geomagnetic field is reported. Initial tests of the modeling procedure developed to compute the ionosphere/magnetosphere-induced fields at satellite orbit are also described. The modeling technique utilizes a liner current element representation of the large scale current system.

Modeling, Fabrication, and Electrical Testing of Metal-Insulator-Metal Diode

DTIC Science & Technology

2011-12-01

1 2. MIM Model 1 2.1 Potential Energy and Image Potential . . . . . . . . . . . . . . . . . . . . . . 1 2.2 Thermionic Emission -limited Current ...4 4 Thermionic emission -limited current through the symmetric MIM diode in figure 1...7 7 Absolute value of tunnel-limited, thermal emission -limited, and total currents vs. applied bias for the

Recent Achievements of the Collaboratory for the Study of Earthquake Predictability

NASA Astrophysics Data System (ADS)

Jordan, T. H.; Liukis, M.; Werner, M. J.; Schorlemmer, D.; Yu, J.; Maechling, P. J.; Jackson, D. D.; Rhoades, D. A.; Zechar, J. D.; Marzocchi, W.

2016-12-01

The Collaboratory for the Study of Earthquake Predictability (CSEP) supports a global program to conduct prospective earthquake forecasting experiments. CSEP testing centers are now operational in California, New Zealand, Japan, China, and Europe with 442 models under evaluation. The California testing center, started by SCEC, Sept 1, 2007, currently hosts 30-minute, 1-day, 3-month, 1-year and 5-year forecasts, both alarm-based and probabilistic, for California, the Western Pacific, and worldwide. Our tests are now based on the hypocentral locations and magnitudes of cataloged earthquakes, but we plan to test focal mechanisms, seismic hazard models, ground motion forecasts, and finite rupture forecasts as well. We have increased computational efficiency for high-resolution global experiments, such as the evaluation of the Global Earthquake Activity Rate (GEAR) model, introduced Bayesian ensemble models, and implemented support for non-Poissonian simulation-based forecasts models. We are currently developing formats and procedures to evaluate externally hosted forecasts and predictions. CSEP supports the USGS program in operational earthquake forecasting and a DHS project to register and test external forecast procedures from experts outside seismology. We found that earthquakes as small as magnitude 2.5 provide important information on subsequent earthquakes larger than magnitude 5. A retrospective experiment for the 2010-2012 Canterbury earthquake sequence showed that some physics-based and hybrid models outperform catalog-based (e.g., ETAS) models. This experiment also demonstrates the ability of the CSEP infrastructure to support retrospective forecast testing. Current CSEP development activities include adoption of the Comprehensive Earthquake Catalog (ComCat) as an authorized data source, retrospective testing of simulation-based forecasts, and support for additive ensemble methods. We describe the open-source CSEP software that is available to researchers as they develop their forecast models. We also discuss how CSEP procedures are being adapted to intensity and ground motion prediction experiments as well as hazard model testing.

Current progress in patient-specific modeling

PubMed Central

2010-01-01

We present a survey of recent advancements in the emerging field of patient-specific modeling (PSM). Researchers in this field are currently simulating a wide variety of tissue and organ dynamics to address challenges in various clinical domains. The majority of this research employs three-dimensional, image-based modeling techniques. Recent PSM publications mostly represent feasibility or preliminary validation studies on modeling technologies, and these systems will require further clinical validation and usability testing before they can become a standard of care. We anticipate that with further testing and research, PSM-derived technologies will eventually become valuable, versatile clinical tools. PMID:19955236

Two-Speed Gearbox Dynamic Simulation Predictions and Test Validation

NASA Technical Reports Server (NTRS)

Lewicki, David G.; DeSmidt, Hans; Smith, Edward C.; Bauman, Steven W.

2010-01-01

Dynamic simulations and experimental validation tests were performed on a two-stage, two-speed gearbox as part of the drive system research activities of the NASA Fundamental Aeronautics Subsonics Rotary Wing Project. The gearbox was driven by two electromagnetic motors and had two electromagnetic, multi-disk clutches to control output speed. A dynamic model of the system was created which included a direct current electric motor with proportional-integral-derivative (PID) speed control, a two-speed gearbox with dual electromagnetically actuated clutches, and an eddy current dynamometer. A six degree-of-freedom model of the gearbox accounted for the system torsional dynamics and included gear, clutch, shaft, and load inertias as well as shaft flexibilities and a dry clutch stick-slip friction model. Experimental validation tests were performed on the gearbox in the NASA Glenn gear noise test facility. Gearbox output speed and torque as well as drive motor speed and current were compared to those from the analytical predictions. The experiments correlate very well with the predictions, thus validating the dynamic simulation methodologies.

Investigation of the effects of external current systems on the MAGSAT data utilizing grid cell modeling techniques

NASA Technical Reports Server (NTRS)

Klumpar, D. M. (Principal Investigator)

1982-01-01

Progress made in reducing MAGSAT data and displaying magnetic field perturbations caused primarily by external currents is reported. A periodic and repeatable perturbation pattern is described that arises from external current effects but appears as unique signatures associated with upper middle latitudes on the Earth's surface. Initial testing of the modeling procedure that was developed to compute the magnetic fields at satellite orbit due to current distributions in the ionosphere and magnetosphere is also discussed. The modeling technique utilizes a linear current element representation of the large scale space current system.

The Effects of the Activities of Current Textbook and 5 E Model on the Attitude of the Students: Sample of "The Global Effects of Natural Resources Unit"

ERIC Educational Resources Information Center

Uzunoz, Abdulkadir

2011-01-01

This study aimed to determine the effects of the activities of current textbook and 5 E Model on the attitude of the students. This study is a research as an experimental model. For testing the effects of geography education supported by 5 E model and geography education based on activities of current textbook attitude of students, controlled…

Fiber Breakage Model for Carbon Composite Stress Rupture Phenomenon: Theoretical Development and Applications

NASA Technical Reports Server (NTRS)

Murthy, Pappu L. N.; Phoenix, S. Leigh; Grimes-Ledesma, Lorie

2010-01-01

Stress rupture failure of Carbon Composite Overwrapped Pressure Vessels (COPVs) is of serious concern to Science Mission and Constellation programs since there are a number of COPVs on board space vehicles with stored gases under high pressure for long durations of time. It has become customary to establish the reliability of these vessels using the so called classic models. The classical models are based on Weibull statistics fitted to observed stress rupture data. These stochastic models cannot account for any additional damage due to the complex pressure-time histories characteristic of COPVs being supplied for NASA missions. In particular, it is suspected that the effects of proof test could significantly reduce the stress rupture lifetime of COPVs. The focus of this paper is to present an analytical appraisal of a model that incorporates damage due to proof test. The model examined in the current paper is based on physical mechanisms such as micromechanics based load sharing concepts coupled with creep rupture and Weibull statistics. For example, the classic model cannot accommodate for damage due to proof testing which every flight vessel undergoes. The paper compares current model to the classic model with a number of examples. In addition, several applications of the model to current ISS and Constellation program issues are also examined.

[The social marketing models and policy advices for HIV rapid testing initiated by non-govermental organization].

PubMed

Liu, H; Cai, L P; Xue, H; Zhao, Y; Wu, D; Zhang, D P; Yin, W Y; Sun, J P

2016-10-06

Currently, a growing number of community-based organizations are providing rapid HIV testing service in various forms, some people with specific needs also purchase HIV rapid test papers through online sales channels, those imply that the demand of HIV self-test is in increasing year by year.In this paper, aims to understand the current situation of HIV rapid test led by CBOs and the approach, strategies and results of social marketing by means of expert interviews and site visits. Hope to illustrate the current situation, and make recommendations for future work.

High Temperature Test Facility Preliminary RELAP5-3D Input Model Description

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bayless, Paul David

A RELAP5-3D input model is being developed for the High Temperature Test Facility at Oregon State University. The current model is described in detail. Further refinements will be made to the model as final as-built drawings are released and when system characterization data are available for benchmarking the input model.

Marginal regression approach for additive hazards models with clustered current status data.

PubMed

Su, Pei-Fang; Chi, Yunchan

2014-01-15

Current status data arise naturally from tumorigenicity experiments, epidemiology studies, biomedicine, econometrics and demographic and sociology studies. Moreover, clustered current status data may occur with animals from the same litter in tumorigenicity experiments or with subjects from the same family in epidemiology studies. Because the only information extracted from current status data is whether the survival times are before or after the monitoring or censoring times, the nonparametric maximum likelihood estimator of survival function converges at a rate of n(1/3) to a complicated limiting distribution. Hence, semiparametric regression models such as the additive hazards model have been extended for independent current status data to derive the test statistics, whose distributions converge at a rate of n(1/2) , for testing the regression parameters. However, a straightforward application of these statistical methods to clustered current status data is not appropriate because intracluster correlation needs to be taken into account. Therefore, this paper proposes two estimating functions for estimating the parameters in the additive hazards model for clustered current status data. The comparative results from simulation studies are presented, and the application of the proposed estimating functions to one real data set is illustrated. Copyright © 2013 John Wiley & Sons, Ltd.

Recent Advances in Simulation of Eddy Current Testing of Tubes and Experimental Validations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reboud, C.; Premel, D.; Lesselier, D.

2007-03-21

Eddy current testing (ECT) is widely used in iron and steel industry for the inspection of tubes during manufacturing. A collaboration between CEA and the Vallourec Research Center led to the development of new numerical functionalities dedicated to the simulation of ECT of non-magnetic tubes by external probes. The achievement of experimental validations led us to the integration of these models into the CIVA platform. Modeling approach and validation results are discussed here. A new numerical scheme is also proposed in order to improve the accuracy of the model.

Recent Advances in Simulation of Eddy Current Testing of Tubes and Experimental Validations

NASA Astrophysics Data System (ADS)

Reboud, C.; Prémel, D.; Lesselier, D.; Bisiaux, B.

2007-03-01

Eddy current testing (ECT) is widely used in iron and steel industry for the inspection of tubes during manufacturing. A collaboration between CEA and the Vallourec Research Center led to the development of new numerical functionalities dedicated to the simulation of ECT of non-magnetic tubes by external probes. The achievement of experimental validations led us to the integration of these models into the CIVA platform. Modeling approach and validation results are discussed here. A new numerical scheme is also proposed in order to improve the accuracy of the model.

Assessment of a novel biomechanical fracture model for distal radius fractures

PubMed Central

2012-01-01

Background Distal radius fractures (DRF) are one of the most common fractures and often need surgical treatment, which has been validated through biomechanical tests. Currently a number of different fracture models are used, none of which resemble the in vivo fracture location. The aim of the study was to develop a new standardized fracture model for DRF (AO-23.A3) and compare its biomechanical behavior to the current gold standard. Methods Variable angle locking volar plates (ADAPTIVE, Medartis) were mounted on 10 pairs of fresh-frozen radii. The osteotomy location was alternated within each pair (New: 10 mm wedge 8 mm / 12 mm proximal to the dorsal / volar apex of the articular surface; Gold standard: 10 mm wedge 20 mm proximal to the articular surface). Each specimen was tested in cyclic axial compression (increasing load by 100 N per cycle) until failure or −3 mm displacement. Parameters assessed were stiffness, displacement and dissipated work calculated for each cycle and ultimate load. Significance was tested using a linear mixed model and Wald test as well as t-tests. Results 7 female and 3 male pairs of radii aged 74 ± 9 years were tested. In most cases (7/10), the two groups showed similar mechanical behavior at low loads with increasing differences at increasing loads. Overall the novel fracture model showed a significant different biomechanical behavior than the gold standard model (p < 0,001). The average final loads resisted were significantly lower in the novel model (860 N ± 232 N vs. 1250 N ± 341 N; p = 0.001). Conclusion The novel biomechanical fracture model for DRF more closely mimics the in vivo fracture site and shows a significantly different biomechanical behavior with increasing loads when compared to the current gold standard. PMID:23244634

Model-based analysis of costs and outcomes of non-invasive prenatal testing for Down's syndrome using cell free fetal DNA in the UK National Health Service.

PubMed

Morris, Stephen; Karlsen, Saffron; Chung, Nancy; Hill, Melissa; Chitty, Lyn S

2014-01-01

Non-invasive prenatal testing (NIPT) for Down's syndrome (DS) using cell free fetal DNA in maternal blood has the potential to dramatically alter the way prenatal screening and diagnosis is delivered. Before NIPT can be implemented into routine practice, information is required on its costs and benefits. We investigated the costs and outcomes of NIPT for DS as contingent testing and as first-line testing compared with the current DS screening programme in the UK National Health Service. We used a pre-existing model to evaluate the costs and outcomes associated with NIPT compared with the current DS screening programme. The analysis was based on a hypothetical screening population of 10,000 pregnant women. Model inputs were taken from published sources. The main outcome measures were number of DS cases detected, number of procedure-related miscarriages and total cost. At a screening risk cut-off of 1∶150 NIPT as contingent testing detects slightly fewer DS cases, has fewer procedure-related miscarriages, and costs the same as current DS screening (around UK£280,000) at a cost of £500 per NIPT. As first-line testing NIPT detects more DS cases, has fewer procedure-related miscarriages, and is more expensive than current screening at a cost of £50 per NIPT. When NIPT uptake increases, NIPT detects more DS cases with a small increase in procedure-related miscarriages and costs. NIPT is currently available in the private sector in the UK at a price of £400-£900. If the NHS cost was at the lower end of this range then at a screening risk cut-off of 1∶150 NIPT as contingent testing would be cost neutral or cost saving compared with current DS screening. As first-line testing NIPT is likely to produce more favourable outcomes but at greater cost. Further research is needed to evaluate NIPT under real world conditions.

Standardized Tests and Froebel's Original Kindergarten Model

ERIC Educational Resources Information Center

Jeynes, William H.

2006-01-01

The author argues that American educators rely on standardized tests at too early an age when administered in kindergarten, particularly given the original intent of kindergarten as envisioned by its founder, Friedrich Froebel. The author examines the current use of standardized tests in kindergarten and the Froebel model, including his emphasis…

Using the NPSS Environment to Model an Altitude Test Facility

NASA Technical Reports Server (NTRS)

Lavelle, Thomas M.; Owen, Albert K.; Huffman, Brian C.

2013-01-01

An altitude test facility was modeled using Numerical Propulsion System Simulation (NPSS). This altitude test facility model represents the most detailed facility model developed in the NPSS architecture. The current paper demonstrates the use of the NPSS system to define the required operating range of a component for the facility. A significant number of additional component models were easily developed to complete the model. Discussed in this paper are the additional components developed and what was done in the development of these components.

Test of electical resistivity and current diffusion modelling on MAST and JET

NASA Astrophysics Data System (ADS)

Keeling, D. L.; Challis, C. D.; Jenkins, I.; Hawkes, N. C.; Lupelli, I.; Michael, C.; de Bock, M. F. M.; the MAST Team; contributors, JET

2018-01-01

Experiments have been carried out on the MAST and JET tokamaks intended to compare the electrical resistivity of the plasma with theoretical formulations. The tests consist of obtaining motional stark effect (MSE) measurements in MHD-free plasmas during plasma current ramp-up (JET and MAST), ramp-down (MAST) and in stationary state (JET and MAST). Simulations of these plasmas are then performed in which the current profile evolution is calculated according to the poloidal field diffusion equation (PFDE) with classical or neoclassical resistivity. Synthetic MSE data are produced in the simulations for direct comparison with the experimental data. It is found that the toroidal current profile evolution modelled using neoclassical resistivity did not match the experimental observations on either device during current ramp-up or ramp-down as concluded from comparison of experimental and synthetic MSE profiles. In these phases, use of neoclassical resistivity in the modelling systematically overestimates the rate of current profile evolution. During the stationary state however, the modelled toroidal current profile matched experimental observations to a high degree of accuracy on both devices using neoclassical resistivity. Whilst no solution to the mismatch in the dynamic phases of the plasma is proposed, it is suggested that some physical process other than MHD which is not captured by the simple diffusive model of current profile evolution is responsible.

Droplet combustion experiment drop tower tests using models of the space flight apparatus

NASA Technical Reports Server (NTRS)

Haggard, J. B.; Brace, M. H.; Kropp, J. L.; Dryer, F. L.

1989-01-01

The Droplet Combustion Experiment (DCE) is an experiment that is being developed to ultimately operate in the shuttle environment (middeck or Spacelab). The current experiment implementation is for use in the 2.2 or 5 sec drop towers at NASA Lewis Research Center. Initial results were reported in the 1986 symposium of this meeting. Since then significant progress was made in drop tower instrumentation. The 2.2 sec drop tower apparatus, a conceptual level model, was improved to give more reproducible performance as well as operate over a wider range of test conditions. Some very low velocity deployments of ignited droplets were observed. An engineering model was built at TRW. This model will be used in the 5 sec drop tower operation to obtain science data. In addition, it was built using the flight design except for changes to accommodate the drop tower requirements. The mechanical and electrical assemblies have the same level of complexity as they will have in flight. The model was tested for functional operation and then delivered to NASA Lewis. The model was then integrated into the 5 sec drop tower. The model is currently undergoing initial operational tests prior to starting the science tests.

Redshift drift constraints on holographic dark energy

NASA Astrophysics Data System (ADS)

He, Dong-Ze; Zhang, Jing-Fei; Zhang, Xin

2017-03-01

The Sandage-Loeb (SL) test is a promising method for probing dark energy because it measures the redshift drift in the spectra of Lyman- α forest of distant quasars, covering the "redshift desert" of 2 ≲ z ≲ 5, which is not covered by existing cosmological observations. Therefore, it could provide an important supplement to current cosmological observations. In this paper, we explore the impact of SL test on the precision of cosmological constraints for two typical holographic dark energy models, i.e., the original holographic dark energy (HDE) model and the Ricci holographic dark energy (RDE) model. To avoid data inconsistency, we use the best-fit models based on current combined observational data as the fiducial models to simulate 30 mock SL test data. The results show that SL test can effectively break the existing strong degeneracy between the present-day matter density Ωm0 and the Hubble constant H 0 in other cosmological observations. For the considered two typical dark energy models, not only can a 30-year observation of SL test improve the constraint precision of Ωm0 and h dramatically, but can also enhance the constraint precision of the model parameters c and α significantly.

Japanese earthquake predictability experiment with multiple runs before and after the 2011 Tohoku-oki earthquake

NASA Astrophysics Data System (ADS)

Hirata, N.; Tsuruoka, H.; Yokoi, S.

2011-12-01

The current Japanese national earthquake prediction program emphasizes the importance of modeling as well as monitoring for a sound scientific development of earthquake prediction research. One major focus of the current program is to move toward creating testable earthquake forecast models. For this purpose, in 2009 we joined the Collaboratory for the Study of Earthquake Predictability (CSEP) and installed, through an international collaboration, the CSEP Testing Centre, an infrastructure to encourage researchers to develop testable models for Japan. We started Japanese earthquake predictability experiment on November 1, 2009. The experiment consists of 12 categories, with 4 testing classes with different time spans (1 day, 3 months, 1 year and 3 years) and 3 testing regions called 'All Japan,' 'Mainland,' and 'Kanto.' A total of 160 models, as of August 2013, were submitted, and are currently under the CSEP official suite of tests for evaluating the performance of forecasts. We will present results of prospective forecast and testing for periods before and after the 2011 Tohoku-oki earthquake. Because a seismic activity has changed dramatically since the 2011 event, performances of models have been affected very much. In addition, as there is the problem of authorized catalogue related to the completeness magnitude, most models did not pass the CSEP consistency tests. Also, we will discuss the retrospective earthquake forecast experiments for aftershocks of the 2011 Tohoku-oki earthquake. Our aim is to describe what has turned out to be the first occasion for setting up a research environment for rigorous earthquake forecasting in Japan.

Japanese earthquake predictability experiment with multiple runs before and after the 2011 Tohoku-oki earthquake

NASA Astrophysics Data System (ADS)

Hirata, N.; Tsuruoka, H.; Yokoi, S.

2013-12-01

The current Japanese national earthquake prediction program emphasizes the importance of modeling as well as monitoring for a sound scientific development of earthquake prediction research. One major focus of the current program is to move toward creating testable earthquake forecast models. For this purpose, in 2009 we joined the Collaboratory for the Study of Earthquake Predictability (CSEP) and installed, through an international collaboration, the CSEP Testing Centre, an infrastructure to encourage researchers to develop testable models for Japan. We started Japanese earthquake predictability experiment on November 1, 2009. The experiment consists of 12 categories, with 4 testing classes with different time spans (1 day, 3 months, 1 year and 3 years) and 3 testing regions called 'All Japan,' 'Mainland,' and 'Kanto.' A total of 160 models, as of August 2013, were submitted, and are currently under the CSEP official suite of tests for evaluating the performance of forecasts. We will present results of prospective forecast and testing for periods before and after the 2011 Tohoku-oki earthquake. Because a seismic activity has changed dramatically since the 2011 event, performances of models have been affected very much. In addition, as there is the problem of authorized catalogue related to the completeness magnitude, most models did not pass the CSEP consistency tests. Also, we will discuss the retrospective earthquake forecast experiments for aftershocks of the 2011 Tohoku-oki earthquake. Our aim is to describe what has turned out to be the first occasion for setting up a research environment for rigorous earthquake forecasting in Japan.

Non-Destructive Techniques Based on Eddy Current Testing

PubMed Central

García-Martín, Javier; Gómez-Gil, Jaime; Vázquez-Sánchez, Ernesto

2011-01-01

Non-destructive techniques are used widely in the metal industry in order to control the quality of materials. Eddy current testing is one of the most extensively used non-destructive techniques for inspecting electrically conductive materials at very high speeds that does not require any contact between the test piece and the sensor. This paper includes an overview of the fundamentals and main variables of eddy current testing. It also describes the state-of-the-art sensors and modern techniques such as multi-frequency and pulsed systems. Recent advances in complex models towards solving crack-sensor interaction, developments in instrumentation due to advances in electronic devices, and the evolution of data processing suggest that eddy current testing systems will be increasingly used in the future. PMID:22163754

Non-destructive techniques based on eddy current testing.

PubMed

García-Martín, Javier; Gómez-Gil, Jaime; Vázquez-Sánchez, Ernesto

2011-01-01

Non-destructive techniques are used widely in the metal industry in order to control the quality of materials. Eddy current testing is one of the most extensively used non-destructive techniques for inspecting electrically conductive materials at very high speeds that does not require any contact between the test piece and the sensor. This paper includes an overview of the fundamentals and main variables of eddy current testing. It also describes the state-of-the-art sensors and modern techniques such as multi-frequency and pulsed systems. Recent advances in complex models towards solving crack-sensor interaction, developments in instrumentation due to advances in electronic devices, and the evolution of data processing suggest that eddy current testing systems will be increasingly used in the future.

Numerical modelling as a cost-reduction tool for probability of detection of bolt hole eddy current testing

NASA Astrophysics Data System (ADS)

Mandache, C.; Khan, M.; Fahr, A.; Yanishevsky, M.

2011-03-01

Probability of detection (PoD) studies are broadly used to determine the reliability of specific nondestructive inspection procedures, as well as to provide data for damage tolerance life estimations and calculation of inspection intervals for critical components. They require inspections on a large set of samples, a fact that makes these statistical assessments time- and cost-consuming. Physics-based numerical simulations of nondestructive testing inspections could be used as a cost-effective alternative to empirical investigations. They realistically predict the inspection outputs as functions of the input characteristics related to the test piece, transducer and instrument settings, which are subsequently used to partially substitute and/or complement inspection data in PoD analysis. This work focuses on the numerical modelling aspects of eddy current testing for the bolt hole inspections of wing box structures typical of the Lockheed Martin C-130 Hercules and P-3 Orion aircraft, found in the air force inventory of many countries. Boundary element-based numerical modelling software was employed to predict the eddy current signal responses when varying inspection parameters related to probe characteristics, crack geometry and test piece properties. Two demonstrator exercises were used for eddy current signal prediction when lowering the driver probe frequency and changing the material's electrical conductivity, followed by subsequent discussions and examination of the implications on using simulated data in the PoD analysis. Despite some simplifying assumptions, the modelled eddy current signals were found to provide similar results to the actual inspections. It is concluded that physics-based numerical simulations have the potential to partially substitute or complement inspection data required for PoD studies, reducing the cost, time, effort and resources necessary for a full empirical PoD assessment.

Development of a model to simulate infection dynamics of Mycobacterium bovis in cattle herds in the United States

PubMed Central

Smith, Rebecca L.; Schukken, Ynte H.; Lu, Zhao; Mitchell, Rebecca M.; Grohn, Yrjo T.

2013-01-01

Objective To develop a mathematical model to simulate infection dynamics of Mycobacterium bovis in cattle herds in the United States and predict efficacy of the current national control strategy for tuberculosis in cattle. Design Stochastic simulation model. Sample Theoretical cattle herds in the United States. Procedures A model of within-herd M bovis transmission dynamics following introduction of 1 latently infected cow was developed. Frequency- and density-dependent transmission modes and 3 tuberculin-test based culling strategies (no test-based culling, constant (annual) testing with test-based culling, and the current strategy of slaughterhouse detection-based testing and culling) were investigated. Results were evaluated for 3 herd sizes over a 10-year period and validated via simulation of known outbreaks of M bovis infection. Results On the basis of 1,000 simulations (1000 herds each) at replacement rates typical for dairy cattle (0.33/y), median time to detection of M bovis infection in medium-sized herds (276 adult cattle) via slaughterhouse surveillance was 27 months after introduction, and 58% of these herds would spontaneously clear the infection prior to that time. Sixty-two percent of medium-sized herds without intervention and 99% of those managed with constant test-based culling were predicted to clear infection < 10 years after introduction. The model predicted observed outbreaks best for frequency-dependent transmission, and probability of clearance was most sensitive to replacement rate. Conclusions and Clinical Relevance Although modeling indicated the current national control strategy was sufficient for elimination of M bovis infection from dairy herds after detection, slaughterhouse surveillance was not sufficient to detect M bovis infection in all herds and resulted in subjectively delayed detection, compared with the constant testing method. Further research is required to economically optimize this strategy. PMID:23865885

Three-dimensional eddy current solution of a polyphase machine test model (abstract)

NASA Astrophysics Data System (ADS)

Pahner, Uwe; Belmans, Ronnie; Ostovic, Vlado

1994-05-01

This abstract describes a three-dimensional (3D) finite element solution of a test model that has been reported in the literature. The model is a basis for calculating the current redistribution effects in the end windings of turbogenerators. The aim of the study is to see whether the analytical results of the test model can be found using a general purpose finite element package, thus indicating that the finite element model is accurate enough to treat real end winding problems. The real end winding problems cannot be solved analytically, as the geometry is far too complicated. The model consists of a polyphase coil set, containing 44 individual coils. This set generates a two pole mmf distribution on a cylindrical surface. The rotating field causes eddy currents to flow in the inner massive and conducting rotor. In the analytical solution a perfect sinusoidal mmf distribution is put forward. The finite element model contains 85824 tetrahedra and 16451 nodes. A complex single scalar potential representation is used in the nonconducting parts. The computation time required was 3 h and 42 min. The flux plots show that the field distribution is acceptable. Furthermore, the induced currents are calculated and compared with the values found from the analytical solution. The distribution of the eddy currents is very close to the distribution of the analytical solution. The most important results are the losses, both local and global. The value of the overall losses is less than 2% away from those of the analytical solution. Also the local distribution of the losses is at any given point less than 7% away from the analytical solution. The deviations of the results are acceptable and are partially due to the fact that the sinusoidal mmf distribution was not modeled perfectly in the finite element method.

Numerical study of the current sheet and PSBL in a magnetotail model

NASA Technical Reports Server (NTRS)

Doxas, I.; Horton, W.; Sandusky, K.; Tajima, T.; Steinolfson, R.

1989-01-01

The current sheet and plasma sheet boundary layer (PSBL) in a magnetotail model are discussed. A test particle code is used to study the response of ensembles of particles to a two-dimensional, time-dependent model of the geomagnetic tail, and test the proposition (Coroniti, 1985a, b; Buchner and Zelenyi, 1986; Chen and Palmadesso, 1986; Martin, 1986) that the stochasticity of the particle orbits in these fields is an important part of the physical mechanism for magnetospheric substorms. The realistic results obtained for the fluid moments of the particle distribution with this simple model, and their insensitivity to initial conditions, is consistent with this hypothesis.

Testing Signal-Detection Models of Yes/No and Two-Alternative Forced-Choice Recognition Memory

ERIC Educational Resources Information Center

Jang, Yoonhee; Wixted, John T.; Huber, David E.

2009-01-01

The current study compared 3 models of recognition memory in their ability to generalize across yes/no and 2-alternative forced-choice (2AFC) testing. The unequal-variance signal-detection model assumes a continuous memory strength process. The dual-process signal-detection model adds a thresholdlike recollection process to a continuous…

A SIGNIFICANCE TEST FOR THE LASSO1

PubMed Central

Lockhart, Richard; Taylor, Jonathan; Tibshirani, Ryan J.; Tibshirani, Robert

2014-01-01

In the sparse linear regression setting, we consider testing the significance of the predictor variable that enters the current lasso model, in the sequence of models visited along the lasso solution path. We propose a simple test statistic based on lasso fitted values, called the covariance test statistic, and show that when the true model is linear, this statistic has an Exp(1) asymptotic distribution under the null hypothesis (the null being that all truly active variables are contained in the current lasso model). Our proof of this result for the special case of the first predictor to enter the model (i.e., testing for a single significant predictor variable against the global null) requires only weak assumptions on the predictor matrix X. On the other hand, our proof for a general step in the lasso path places further technical assumptions on X and the generative model, but still allows for the important high-dimensional case p > n, and does not necessarily require that the current lasso model achieves perfect recovery of the truly active variables. Of course, for testing the significance of an additional variable between two nested linear models, one typically uses the chi-squared test, comparing the drop in residual sum of squares (RSS) to a χ12 distribution. But when this additional variable is not fixed, and has been chosen adaptively or greedily, this test is no longer appropriate: adaptivity makes the drop in RSS stochastically much larger than χ12 under the null hypothesis. Our analysis explicitly accounts for adaptivity, as it must, since the lasso builds an adaptive sequence of linear models as the tuning parameter λ decreases. In this analysis, shrinkage plays a key role: though additional variables are chosen adaptively, the coefficients of lasso active variables are shrunken due to the l1 penalty. Therefore, the test statistic (which is based on lasso fitted values) is in a sense balanced by these two opposing properties—adaptivity and shrinkage—and its null distribution is tractable and asymptotically Exp(1). PMID:25574062

TOXICITY TESTING IN THE 21ST CENTURY: A VISION AND A STRATEGY

PubMed Central

Krewski, Daniel; Acosta, Daniel; Andersen, Melvin; Anderson, Henry; Bailar, John C.; Boekelheide, Kim; Brent, Robert; Charnley, Gail; Cheung, Vivian G.; Green, Sidney; Kelsey, Karl T.; Kerkvliet, Nancy I.; Li, Abby A.; McCray, Lawrence; Meyer, Otto; Patterson, Reid D.; Pennie, William; Scala, Robert A.; Solomon, Gina M.; Stephens, Martin; Yager, James; Zeise, Lauren

2015-01-01

With the release of the landmark report Toxicity Testing in the 21st Century: A Vision and a Strategy, the U.S. National Academy of Sciences, in 2007, precipitated a major change in the way toxicity testing is conducted. It envisions increased efficiency in toxicity testing and decreased animal usage by transitioning from current expensive and lengthy in vivo testing with qualitative endpoints to in vitro toxicity pathway assays on human cells or cell lines using robotic high-throughput screening with mechanistic quantitative parameters. Risk assessment in the exposed human population would focus on avoiding significant perturbations in these toxicity pathways. Computational systems biology models would be implemented to determine the dose-response models of perturbations of pathway function. Extrapolation of in vitro results to in vivo human blood and tissue concentrations would be based on pharmacokinetic models for the given exposure condition. This practice would enhance human relevance of test results, and would cover several test agents, compared to traditional toxicological testing strategies. As all the tools that are necessary to implement the vision are currently available or in an advanced stage of development, the key prerequisites to achieving this paradigm shift are a commitment to change in the scientific community, which could be facilitated by a broad discussion of the vision, and obtaining necessary resources to enhance current knowledge of pathway perturbations and pathway assays in humans and to implement computational systems biology models. Implementation of these strategies would result in a new toxicity testing paradigm firmly based on human biology. PMID:20574894

Serological diagnosis of bovine neosporosis: a Bayesian evaluation of two antibody ELISA tests for in vivo diagnosis in purchased and abortion cattle.

PubMed

Roelandt, S; Van der Stede, Y; Czaplicki, G; Van Loo, H; Van Driessche, E; Dewulf, J; Hooyberghs, J; Faes, C

2015-06-06

Currently, there are no perfect reference tests for the in vivo detection of Neospora caninum infection. Two commercial N caninum ELISA tests are currently used in Belgium for bovine sera (TEST A and TEST B). The goal of this study is to evaluate these tests used at their current cut-offs, with a no gold standard approach, for the test purpose of (1) demonstration of freedom of infection at purchase and (2) diagnosis in aborting cattle. Sera of two study populations, Abortion population (n=196) and Purchase population (n=514), were selected and tested with both ELISA's. Test results were entered in a Bayesian model with informative priors on population prevalences only (Scenario 1). As sensitivity analysis, two more models were used: one with informative priors on test diagnostic accuracy (Scenario 2) and one with all priors uninformative (Scenario 3). The accuracy parameters were estimated from the first model: diagnostic sensitivity (Test A: 93.54 per cent-Test B: 86.99 per cent) and specificity (Test A: 90.22 per cent-Test B: 90.15 per cent) were high and comparable (Bayesian P values >0.05). Based on predictive values in the two study populations, both tests were fit for purpose, despite an expected false negative fraction of ±0.5 per cent in the Purchase population and ±5 per cent in the Abortion population. In addition, a false positive fraction of ±3 per cent in the overall Purchase population and ±4 per cent in the overall Abortion population was found. British Veterinary Association.

Aerodynamic and hydrodynamic model tests of the Enserch Garden Banks floating production facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, E.W.; Bauer, T.C.; Kelly, P.J.

1995-12-01

This paper presents the results of aerodynamic and hydrodynamic model tests of the Enserch Garden Banks, a semisubmersible Floating Production Facility (FPF) moored in 2,190-ft waters. During the wind tunnel tests, the steady component of wind and current forces/moments at various skew and heel axes were measured. The results were compared and calibrated against analytical calculations using techniques recommended by ABS and API. During the wave basin recommend test the mooring line tensions and vessel motions including the effects of dynamic wind and current were measured. An analytical calculation of the airgap, vessel motions, and mooring line loads were comparedmore » with wave basin model test results. This paper discusses the test objectives, test setups and agendas for wind and wave basin testing of a deepwater permanently moored floating production system. The experience from these tests and the comparison of measured tests results with analytical calculations will be of value to designers and operators contemplating the use of a semisubmersible based floating production system. The analysis procedures are aimed at estimating (1) vessel motions, (2) airgap, and (3) mooring line tensions with reasonable accuracy. Finally, this paper demonstrates how the model test results were interpolated and adapted in the design loop.« less

Formula Gives Better Contact-Resistance Values

NASA Technical Reports Server (NTRS)

Lieneweg, Udo; Hannaman, David J.

1988-01-01

Lateral currents in contact strips taken into account. Four-terminal test structures added to intergrated circuits to enable measurement of interfacial resistivities of contacts between thin conducting layers. Thin-film model simplified quasi-two-dimensional potential model that accounts adequately for complicated three-dimensional, nonuniform current densitites. Effects of nonuniformity caused by lateral current flow in strips summarized in equivalent resistance Rs and voltage Vs.

Assessing Intelligence in Children and Youth Living in the Netherlands

ERIC Educational Resources Information Center

Hurks, Petra P. M.; Bakker, Helen

2016-01-01

In this article, we briefly describe the history of intelligence test use with children and youth in the Netherlands, explain which models of intelligence guide decisions about test use, and detail how intelligence tests are currently being used in Dutch school settings. Empirically supported and theoretical models studying the structure of human…

Large Dataset of Acute Oral Toxicity Data Created for Testing in Silico Models (ASCCT meeting)

EPA Science Inventory

Acute toxicity data is a common requirement for substance registration in the US. Currently only data derived from animal tests are accepted by regulatory agencies, and the standard in vivo tests use lethality as the endpoint. Non-animal alternatives such as in silico models are ...

Extension to the dynamic modeling of the large angle magnetic suspension test fixture. M.S. Thesis - Old Dominion Univ., May 1995 Progress Report, 1 Nov. 1994 - 30 Apr. 1995

NASA Technical Reports Server (NTRS)

Foster, Lucas E.; Britcher, Colin P.

1995-01-01

The Large Angle Magnetic Suspension Test Fixture (LAMSTF) is a laboratory scale proof-of-concept system. The configuration is unique in that the electromagnets are mounted in a circular planar array. A mathematical model of the system had previously been developed, but was shown to have inaccuracies. These inaccuracies showed up in the step responses. Eddy currents were found to be the major cause of the modeling errors. In the original system, eddy currents existed in the aluminum baseplate, iron cores, and the sensor support frame. An attempt to include the eddy current dynamics in the system model is presented. The dynamics of a dummy sensor ring were added to the system. Adding the eddy current dynamics to the simulation improves the way it compares to the actual experiment. Also presented is a new method of determining the yaw angle of the suspended element. From the coil currents the yaw angle can be determined and the controller can be updated to suspend at the new current. This method has been used to demonstrate a 360 degree yaw angle rotation.

U.S. Army Workshop on Solid-Propellant Ignition and Combustion Modeling.

DTIC Science & Technology

1997-07-01

saving tool in the design, development, testing, and evaluation of future gun-propulsion systems , and that, under current funding constraints, research...53 7.1 What systems are currently being addressed...9 ............. . . .. .. . . . . . . . . . . . . . . . . . . . . . . . . 56 7.5 What model systems might be valuable for

Forecasting in foodservice: model development, testing, and evaluation.

PubMed

Miller, J L; Thompson, P A; Orabella, M M

1991-05-01

This study was designed to develop, test, and evaluate mathematical models appropriate for forecasting menu-item production demand in foodservice. Data were collected from residence and dining hall foodservices at Ohio State University. Objectives of the study were to collect, code, and analyze the data; develop and test models using actual operation data; and compare forecasting results with current methods in use. Customer count was forecast using deseasonalized simple exponential smoothing. Menu-item demand was forecast by multiplying the count forecast by a predicted preference statistic. Forecasting models were evaluated using mean squared error, mean absolute deviation, and mean absolute percentage error techniques. All models were more accurate than current methods. A broad spectrum of forecasting techniques could be used by foodservice managers with access to a personal computer and spread-sheet and database-management software. The findings indicate that mathematical forecasting techniques may be effective in foodservice operations to control costs, increase productivity, and maximize profits.

An EMTP system level model of the PMAD DC test bed

NASA Technical Reports Server (NTRS)

Dravid, Narayan V.; Kacpura, Thomas J.; Tam, Kwa-Sur

1991-01-01

A power management and distribution direct current (PMAD DC) test bed was set up at the NASA Lewis Research Center to investigate Space Station Freedom Electric Power Systems issues. Efficiency of test bed operation significantly improves with a computer simulation model of the test bed as an adjunct tool of investigation. Such a model is developed using the Electromagnetic Transients Program (EMTP) and is available to the test bed developers and experimenters. The computer model is assembled on a modular basis. Device models of different types can be incorporated into the system model with only a few lines of code. A library of the various model types is created for this purpose. Simulation results and corresponding test bed results are presented to demonstrate model validity.

Development and Testing of High Current Hollow Cathodes for High Power Hall Thrusters

NASA Technical Reports Server (NTRS)

Kamhawi, Hani; Van Noord, Jonathan

2012-01-01

NASA's Office of the Chief Technologist In-Space Propulsion project is sponsoring the testing and development of high power Hall thrusters for implementation in NASA missions. As part of the project, NASA Glenn Research Center is developing and testing new high current hollow cathode assemblies that can meet and exceed the required discharge current and life-time requirements of high power Hall thrusters. This paper presents test results of three high current hollow cathode configurations. Test results indicated that two novel emitter configurations were able to attain lower peak emitter temperatures compared to state-of-the-art emitter configurations. One hollow cathode configuration attained a cathode orifice plate tip temperature of 1132 degC at a discharge current of 100 A. More specifically, test and analysis results indicated that a novel emitter configuration had minimal temperature gradient along its length. Future work will include cathode wear tests, and internal emitter temperature and plasma properties measurements along with detailed physics based modeling.

Precision measurement and modeling of superconducting magnetic bearings for the satellite test of the equivalence principle

NASA Astrophysics Data System (ADS)

Sapilewski, Glen Alan

The Satellite Test of the Equivalence Principle (STEP) is a modern version of Galileo's experiment of dropping two objects from the leaning tower of Pisa. The Equivalence Principle states that all objects fall with the same acceleration, independent of their composition. The primary scientific objective of STEP is to measure a possible violation of the Equivalence Principle one million times better than the best ground based tests. This extraordinary sensitivity is made possible by using cryogenic differential accelerometers in the space environment. Critical to the STEP experiment is a sound fundamental understanding of the behavior of the superconducting magnetic linear bearings used in the accelerometers. We have developed a theoretical bearing model and a precision measuring system with which to validate the model. The accelerometers contain two concentric hollow cylindrical test masses, of different materials, each levitated and constrained to axial motion by a superconducting magnetic bearing. Ensuring that the bearings satisfy the stringent mission specifications requires developing new testing apparatus and methods. The bearing is tested using an actively-controlled table which tips it relative to gravity. This balances the magnetic forces from the bearing against a component of gravity. The magnetic force profile of the bearing can be mapped by measuring the tilt necessary to position the test mass at various locations. An operational bearing has been built and is being used to verify the theoretical levitation models. The experimental results obtained from the bearing test apparatus were inconsistent with the previous models used for STEP bearings. This led to the development of a new bearing model that includes the influence of surface current variations in the bearing wires and the effect of the superconducting transformer. The new model, which has been experimentally verified, significantly improves the prediction of levitation current, accurately estimates the relationship between tilting and translational modes, and predicts the dependence of radial mode frequencies on the bearing current. In addition, we developed a new model for the forces produced by trapped magnetic fluxons, a potential source of imperfections in the bearing. This model estimates the forces between magnetic fluxons trapped in separate superconducting objects.

Blind tests of methods for InSight Mars mission: Open scientific challenge

NASA Astrophysics Data System (ADS)

Clinton, John; Ceylan, Savas; Giardini, Domenico; Khan, Amir; van Driel, Martin; Böse, Maren; Euchner, Fabian; Garcia, Raphael F.; Drilleau, Mélanie; Lognonné, Philippe; Panning, Mark; Banerdt, Bruce

2017-04-01

The Marsquake Service (MQS) will be the ground segment service within the InSight mission to Mars, which will deploy a single seismic station on Elysium Planitia in November 2018. The main tasks of the MQS are the identification and characterisation of seismicity, and managing the Martian seismic event catalogue. In advance of the mission, we have developed a series of single station event location methods that rely on a priori 1D and 3D structural models. In coordination with the Mars Structural Service, we expect to use iterative inversion techniques to revise these structural models and event locations. In order to seek methodological advancements and test our current approaches, we have designed a blind test case using Martian synthetics combined with realistic noise models for the Martian surface. We invite all scientific parties that are interested in single station approaches and in exploring the Martian time-series to participate and contribute to our blind test. We anticipate the test will can improve currently developed location and structural inversion techniques, and also allow us explore new single station techniques for moment tensor and magnitude determination. The waveforms for our test case are computed employing AxiSEM and Instaseis for a randomly selected 1D background model and event catalogue that is statistically consistent with our current expectation of Martian seismicity. Realistic seismic surface noise is superimposed to generate a continuous time-series spanning 6 months. The event catalog includes impacts as well as Martian quakes. The temporal distribution of the seismicity in the timeseries, as well as the true structural model, are not be known to any participating parties including MQS till the end of competition. We provide our internal tools such as event location codes, suite of background models, seismic phase travel times, in order to support researchers who are willing to use/improve our current methods. Following the deadline of our blind test in late 2017, we plan to combine all outcomes in an article with all participants as co-authors.

Early experiences building a software quality prediction model

NASA Technical Reports Server (NTRS)

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

1990-01-01

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

Does Test Anxiety Induce Measurement Bias in Cognitive Ability Tests?

ERIC Educational Resources Information Center

Reeve, Charlie L.; Bonaccio, Silvia

2008-01-01

Although test anxiety is typically negatively related to performance on cognitive ability tests, little research has systematically investigated whether differences in test anxiety result in measurement bias on cognitive ability tests. The current paper uses a structural equation modeling technique to explicitly test for measurement bias due to…

Current and future constraints on extended Bekenstein-type models for a varying fine-structure constant

NASA Astrophysics Data System (ADS)

Alves, C. S.; Leite, A. C. O.; Martins, C. J. A. P.; Silva, T. A.; Berge, S. A.; Silva, B. S. A.

2018-01-01

There is a growing interest in astrophysical tests of the stability of dimensionless fundamental couplings, such as the fine-structure constant α , as an optimal probe of new physics. The imminent arrival of the ESPRESSO spectrograph will soon enable significant gains in the precision and accuracy of these tests and widen the range of theoretical models that can be tightly constrained. Here we illustrate this by studying proposed extensions of the Bekenstein-type models for the evolution of α that allow different couplings of the scalar field to both dark matter and dark energy. We use a combination of current astrophysical and local laboratory data (from tests with atomic clocks) to show that these couplings are constrained to parts per million level, with the constraints being dominated by the atomic clocks. We also quantify the expected improvements from ESPRESSO and other future spectrographs, and briefly discuss possible observational strategies, showing that these facilities can improve current constraints by more than an order of magnitude.

Radiation induced currents in mineral-insulated cables and in pick-up coils: model calculations and experimental verification in the BR1 reactor

NASA Astrophysics Data System (ADS)

Vermeeren, Ludo; Leysen, Willem; Brichard, Benoit

2018-01-01

Mineral-insulated (MI) cables and Low-Temperature Co-fired Ceramic (LTCC) magnetic pick-up coils are intended to be installed in various position in ITER. The severe ITER nuclear radiation field is expected to lead to induced currents that could perturb diagnostic measurements. In order to assess this problem and to find mitigation strategies models were developed for the calculation of neutron-and gamma-induced currents in MI cables and in LTCC coils. The models are based on calculations with the MCNPX code, combined with a dedicated model for the drift of electrons stopped in the insulator. The gamma induced currents can be easily calculated with a single coupled photon-electron MCNPX calculation. The prompt neutron induced currents requires only a single coupled neutron-photon-electron MCNPX run. The various delayed neutron contributions require a careful analysis of all possibly relevant neutron-induced reaction paths and a combination of different types of MCNPX calculations. The models were applied for a specific twin-core copper MI cable, for one quad-core copper cable and for silver conductor LTCC coils (one with silver ground plates in order to reduce the currents and one without such silver ground plates). Calculations were performed for irradiation conditions (neutron and gamma spectra and fluxes) in relevant positions in ITER and in the Y3 irradiation channel of the BR1 reactor at SCK•CEN, in which an irradiation test of these four test devices was carried out afterwards. We will present the basic elements of the models and show the results of all relevant partial currents (gamma and neutron induced, prompt and various delayed currents) in BR1-Y3 conditions. Experimental data will be shown and analysed in terms of the respective contributions. The tests were performed at reactor powers of 350 kW and 1 MW, leading to thermal neutron fluxes of 1E11 n/cm2s and 3E11 n/cm2s, respectively. The corresponding total radiation induced currents are ranging from 1 to 7 nA only, putting a challenge on the acquisition system and on the data analysis. The detailed experimental results will be compared with the corresponding values predicted by the model. The overall agreement between the experimental data and the model predictions is fairly good, with very consistent data for the main delayed current components, while the lower amplitude delayed currents and some of the prompt contributions show some minor discrepancies.

Inferring electric fields and currents from ground magnetometer data - A test with theoretically derived inputs

NASA Technical Reports Server (NTRS)

Wolf, R. A.; Kamide, Y.

1983-01-01

Advanced techniques considered by Kamide et al. (1981) seem to have the potential for providing observation-based high time resolution pictures of the global ionospheric current and electric field patterns for interesting events. However, a reliance on the proposed magnetogram-inversion schemes for the deduction of global ionospheric current and electric field patterns requires proof that reliable results are obtained. 'Theoretical' tests of the accuracy of the magnetogram inversion schemes have, therefore, been considered. The present investigation is concerned with a test, involving the developed KRM algorithm and the Rice Convection Model (RCM). The test was successful in the sense that there was overall agreement between electric fields and currents calculated by the RCM and KRM schemes.

Large Dataset of Acute Oral Toxicity Data Created for Testing ...

EPA Pesticide Factsheets

Acute toxicity data is a common requirement for substance registration in the US. Currently only data derived from animal tests are accepted by regulatory agencies, and the standard in vivo tests use lethality as the endpoint. Non-animal alternatives such as in silico models are being developed due to animal welfare and resource considerations. We compiled a large dataset of oral rat LD50 values to assess the predictive performance currently available in silico models. Our dataset combines LD50 values from five different sources: literature data provided by The Dow Chemical Company, REACH data from eChemportal, HSDB (Hazardous Substances Data Bank), RTECS data from Leadscope, and the training set underpinning TEST (Toxicity Estimation Software Tool). Combined these data sources yield 33848 chemical-LD50 pairs (data points), with 23475 unique data points covering 16439 compounds. The entire dataset was loaded into a chemical properties database. All of the compounds were registered in DSSTox and 59.5% have publically available structures. Compounds without a structure in DSSTox are currently having their structures registered. The structural data will be used to evaluate the predictive performance and applicable chemical domains of three QSAR models (TIMES, PROTOX, and TEST). Future work will combine the dataset with information from ToxCast assays, and using random forest modeling, assess whether ToxCast assays are useful in predicting acute oral toxicity. Pre

Experimental Study on New Multi-Column Tension-Leg-Type Floating Wind Turbine

NASA Astrophysics Data System (ADS)

Zhao, Yong-sheng; She, Xiao-he; He, Yan-ping; Yang, Jian-min; Peng, Tao; Kou, Yu-feng

2018-04-01

Deep-water regions often have winds favorable for offshore wind turbines, and floating turbines currently show the greatest potential to exploit such winds. This work established proper scaling laws for model tests, which were then implemented in the construction of a model wind turbine with optimally designed blades. The aerodynamic, hydrodynamic, and elastic characteristics of the proposed new multi-column tension-leg-type floating wind turbine (WindStar TLP system) were explored in the wave tank testing of a 1:50 scale model at the State Key Laboratory of Ocean Engineering at Shanghai Jiao Tong University. Tests were conducted under conditions of still water, white noise waves, irregular waves, and combined wind, wave, and current loads. The results established the natural periods of the motion, damping, motion response amplitude operators, and tendon tensions of the WindStar TLP system under different environmental conditions, and thus could serve as a reference for further research. Key words: floating wind turbine, model test, WindStar TLP, dynamic response

Calculations of current-induced forces on moored tankers, using the theory of manoeuvring ships

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mirza, S.

1996-12-31

The knowledge of current induced loads on moored tankers is important in the design of mooring lines. Normally, these current loads are determined from controlled laboratory experiments and field tests or from the Oil Companies International Marine Forum (OCIMF) data (1977). Chakrabarti (1995) mentions that the validity of some of this data is doubtful, and he conducted some tank tests. To save time involved in preparation of elaborate tank tests, it will be useful to have some analytical tools to calculate the current induced loads. In this paper, an attempt has been made to calculate the lateral forces in currentmore » only conditions, using the theory of manoeuvring ships. The manoeuvring model was developed by Wellicome (1981). The sway forces on the hull are modelled by conformal transformation of the hull into a circle plane and applying the flow field. The forces on the bilge keel are modelled by vortex panel method. The results for the simulation are compared with the test results of Chakrabarti (1995). There is good correlation between the experimental and theoretical results for the case of hull with bilge keels. This is true for the streaming flow velocity up to an angle of 45 to the longitudinal direction of the hull. For the case of bare hull, the computational model grossly underpredicts the sway forces. This may be due to the dominance of viscous forces than the potential ones.« less

Proactive Personality and the Successful Job Search : A Field Investigation with College Graduates

ERIC Educational Resources Information Center

Brown, Douglas J.; Cober, Richard T.; Kane, Kevin; Levy, Paul E.; Shalhoop, Jarrett

2006-01-01

The current article tests a model of proactive personality and job search success with a sample of 180 graduating college students. Using structural equation modeling, the authors tested a theoretical model that specified the relations among proactive personality, job search self-efficacy, job search behaviors, job search effort, and job search…

A Semiparametric Model for Jointly Analyzing Response Times and Accuracy in Computerized Testing

ERIC Educational Resources Information Center

Wang, Chun; Fan, Zhewen; Chang, Hua-Hua; Douglas, Jeffrey A.

2013-01-01

The item response times (RTs) collected from computerized testing represent an underutilized type of information about items and examinees. In addition to knowing the examinees' responses to each item, we can investigate the amount of time examinees spend on each item. Current models for RTs mainly focus on parametric models, which have the…

Preliminary eddy current modelling for the large angle magnetic suspension test fixture

NASA Technical Reports Server (NTRS)

Britcher, Colin

1994-01-01

This report presents some recent developments in the mathematical modeling of the Large Angle Magnetic Suspension Test Fixture (LAMSTF) at NASA Langley Research Center. It is shown that these effects are significant, but may be amenable to analysis, modeling and measurement. A theoretical framework is presented, together with a comparison of computed and experimental data.

Commissioning of horizontal-bend superconducting magnet for Jefferson Lab's 11-GeV super high momentum spectrometer

DOE PAGES

Sun, Eric; Brindza, Paul D.; Lassiter, Steven R.; ...

2016-03-02

Commissioning characteristics of the Superconducting High Momentum Spectrometer (SHMS) Horizontal Bend (HB) magnet was presented. Pre-commissioning peer review of the magnet uncovered issues with eddy currents in the thermal shield, resulting in additional testing and modeling of the magnet. A three-stage test plan was discussed. A solution of using a small dump resistor and a warm thermal shield was presented. Analyses illustrated that it was safe to run the magnet to full test current. As a result, the HB magnet was successfully cooled to 4 K and reached its maximum test current of 4000 A.

V/STOL wind-tunnel testing

NASA Technical Reports Server (NTRS)

Koenig, D. G.

1984-01-01

Factors influencing effective program planning for V/STOL wind-tunnel testing are discussed. The planning sequence itself, which includes a short checklist of considerations that could enhance the value of the tests, is also described. Each of the considerations, choice of wind tunnel, type of model installation, model development and test operations, is discussed, and examples of appropriate past and current V/STOL test programs are provided. A short survey of the moderate to large subsonic wind tunnels is followed by a review of several model installations, from two-dimensional to large-scale models of complete aircraft configurations. Model sizing, power simulation, and planning are treated, including three areas is test operations: data-acquisition systems, acoustic measurements in wind tunnels, and flow surveying.

A 3D unstructured grid nearshore hydrodynamic model based on the vortex force formalism

NASA Astrophysics Data System (ADS)

Zheng, Peng; Li, Ming; van der A, Dominic A.; van der Zanden, Joep; Wolf, Judith; Chen, Xueen; Wang, Caixia

2017-08-01

A new three-dimensional nearshore hydrodynamic model system is developed based on the unstructured-grid version of the third generation spectral wave model SWAN (Un-SWAN) coupled with the three-dimensional ocean circulation model FVCOM to enable the full representation of the wave-current interaction in the nearshore region. A new wave-current coupling scheme is developed by adopting the vortex-force (VF) scheme to represent the wave-current interaction. The GLS turbulence model is also modified to better reproduce wave-breaking enhanced turbulence, together with a roller transport model to account for the effect of surface wave roller. This new model system is validated first against a theoretical case of obliquely incident waves on a planar beach, and then applied to three test cases: a laboratory scale experiment of normal waves on a beach with a fixed breaker bar, a field experiment of oblique incident waves on a natural, sandy barred beach (Duck'94 experiment), and a laboratory study of normal-incident waves propagating around a shore-parallel breakwater. Overall, the model predictions agree well with the available measurements in these tests, illustrating the robustness and efficiency of the present model for very different spatial scales and hydrodynamic conditions. Sensitivity tests indicate the importance of roller effects and wave energy dissipation on the mean flow (undertow) profile over the depth. These tests further suggest to adopt a spatially varying value for roller effects across the beach. In addition, the parameter values in the GLS turbulence model should be spatially inhomogeneous, which leads to better prediction of the turbulent kinetic energy and an improved prediction of the undertow velocity profile.

Non-linear behaviour of electrical parameters in porous, water-saturated rocks: a model to predict pore size distribution

NASA Astrophysics Data System (ADS)

Hallbauer-Zadorozhnaya, Valeriya; Santarato, Giovanni; Abu Zeid, Nasser

2015-08-01

In this paper, two separate but related goals are tackled. The first one is to demonstrate that in some saturated rock textures the non-linear behaviour of induced polarization (IP) and the violation of Ohm's law not only are real phenomena, but they can also be satisfactorily predicted by a suitable physical-mathematical model, which is our second goal. This model is based on Fick's second law. As the model links the specific dependence of resistivity and chargeability of a laboratory sample to the injected current and this in turn to its pore size distribution, it is able to predict pore size distribution from laboratory measurements, in good agreement with mercury injection capillary pressure test results. This fact opens up the possibility for hydrogeophysical applications on a macro scale. Mathematical modelling shows that the chargeability acquired in the field under normal conditions, that is at low current, will always be very small and approximately proportional to the applied current. A suitable field test site for demonstrating the possible reliance of both resistivity and chargeability on current was selected and a specific measuring strategy was established. Two data sets were acquired using different injected current strengths, while keeping the charging time constant. Observed variations of resistivity and chargeability are in agreement with those predicted by the mathematical model. These field test data should however be considered preliminary. If confirmed by further evidence, these facts may lead to changing the procedure of acquiring field measurements in future, and perhaps may encourage the design and building of a new specific geo-resistivity meter. This paper also shows that the well-known Marshall and Madden's equations based on Fick's law cannot be solved without specific boundary conditions.

Wave-current interactions at the FloWave Ocean Energy Research Facility

NASA Astrophysics Data System (ADS)

Noble, Donald; Davey, Thomas; Steynor, Jeffrey; Bruce, Tom; Smith, Helen; Kaklis, Panagiotis

2015-04-01

Physical scale model testing is an important part of the marine renewable energy development process, allowing the study of forces and device behaviour in a controlled environment prior to deployment at sea. FloWave is a new state-of-the-art ocean energy research facility, designed to provide large scale physical modelling services to the tidal and wave sector. It has the unique ability to provide complex multi-directional waves that can be combined with currents from any direction in the 25m diameter circular tank. The facility is optimised for waves around 2s period and 0.4m height, and is capable of generating currents upwards of 1.6m/s. This offers the ability to model metocean conditions suitable for most renewable energy devices at a typical scale of between 1:10 and 1:40. The test section is 2m deep, which can be classed as intermediate-depth for most waves of interest, thus the full dispersion equation must be solved as the asymptotic simplifications do not apply. The interaction between waves and currents has been studied in the tank. This has involved producing in the tank sets of regular waves, focussed wave groups, and random sea spectra including multi-directional sea states. These waves have been both inline-with and opposing the current, as well as investigating waves at arbitrary angles to the current. Changes in wave height and wavelength have been measured, and compared with theoretical results. Using theoretical wave-current interaction models, methods have been explored to "correct" the wave height in the central test area of the tank when combined with a steady current. This allows the wave height with current to be set equal to that without a current. Thus permitting, for example, direct comparison of device motion response between tests with and without current. Alternatively, this would also permit a specific wave height and current combination to be produced in the tank, reproducing recorded conditions at a particular site of interest. The initial tests used a correction factor based on a linear combination of wave and current (Smith 1997), which was found to be reasonably accurate, although the requirement for higher order theory is also explored. FloWave is a new facility that offers the ability to study wave-current interactions at arbitrary angles with relatively fast currents. This is important as waves and tidal currents at sites of interest for renewable energy generation may not be aligned (Lewis et al. 2014), and so better understanding of these conditions is required. References Lewis, M.J. et al., 2014. Realistic wave conditions and their influence on quantifying the tidal stream energy resource. Applied Energy, 136, pp.495-508. Smith, J.M., 1997. Coastal Engineering Technical Note One-dimensional wave-current interaction (CETN IV-9), Vicksburg, MS.

An experimental comparison of several current viscoplastic constitutive models at elevated temperature

NASA Technical Reports Server (NTRS)

James, G. H.; Imbrie, P. K.; Hill, P. S.; Allen, D. H.; Haisler, W. E.

1988-01-01

Four current viscoplastic models are compared experimentally for Inconel 718 at 593 C. This material system responds with apparent negative strain rate sensitivity, undergoes cyclic work softening, and is susceptible to low cycle fatigue. A series of tests were performed to create a data base from which to evaluate material constants. A method to evaluate the constants is developed which draws on common assumptions for this type of material, recent advances by other researchers, and iterative techniques. A complex history test, not used in calculating the constants, is then used to compare the predictive capabilities of the models. The combination of exponentially based inelastic strain rate equations and dynamic recovery is shown to model this material system with the greatest success. The method of constant calculation developed was successfully applied to the complex material response encountered. Backstress measuring tests were found to be invaluable and to warrant further development.

Formal methods for test case generation

NASA Technical Reports Server (NTRS)

Rushby, John (Inventor); De Moura, Leonardo Mendonga (Inventor); Hamon, Gregoire (Inventor)

2011-01-01

The invention relates to the use of model checkers to generate efficient test sets for hardware and software systems. The method provides for extending existing tests to reach new coverage targets; searching *to* some or all of the uncovered targets in parallel; searching in parallel *from* some or all of the states reached in previous tests; and slicing the model relative to the current set of coverage targets. The invention provides efficient test case generation and test set formation. Deep regions of the state space can be reached within allotted time and memory. The approach has been applied to use of the model checkers of SRI's SAL system and to model-based designs developed in Stateflow. Stateflow models achieving complete state and transition coverage in a single test case are reported.

Radiation detection method and system using the sequential probability ratio test

DOEpatents

Nelson, Karl E [Livermore, CA; Valentine, John D [Redwood City, CA; Beauchamp, Brock R [San Ramon, CA

2007-07-17

A method and system using the Sequential Probability Ratio Test to enhance the detection of an elevated level of radiation, by determining whether a set of observations are consistent with a specified model within a given bounds of statistical significance. In particular, the SPRT is used in the present invention to maximize the range of detection, by providing processing mechanisms for estimating the dynamic background radiation, adjusting the models to reflect the amount of background knowledge at the current point in time, analyzing the current sample using the models to determine statistical significance, and determining when the sample has returned to the expected background conditions.

An Overview of Models of Speaking Performance and Its Implications for the Development of Procedural Framework for Diagnostic Speaking Tests

ERIC Educational Resources Information Center

Zhao, Zhongbao

2013-01-01

This paper aims at developing a procedural framework for the development and validation of diagnostic speaking tests. The researcher reviews the current available models of speaking performance, analyzes the distinctive features and then points out the implications for the development of a procedural framework for diagnostic speaking tests. On…

Optimizing Infant HIV Diagnosis in Resource-Limited Settings: Modeling the Impact of HIV DNA PCR Testing at Birth.

PubMed

Chiu, Alexander; Modi, Surbhi; Rivadeneira, Emilia D; Koumans, Emilia H

2016-12-01

Early antiretroviral therapy (ART) initiation in HIV-infected infants significantly improves survival but is often delayed in resource-limited settings. Adding HIV testing of infants at birth to the current recommendation of testing at age 4-6 weeks may improve testing rates and decrease time to ART initiation. We modeled the benefit of adding HIV testing at birth to the current 6-week testing algorithm. Microsoft Excel was used to create a decision-tree model of the care continuum for the estimated 1,400,000 HIV-infected women and their infants in sub-Saharan Africa in 2012. The model assumed average published rates for facility births (42.9%), prevention of mother-to-child HIV transmission utilization (63%), mother-to-child-transmission rates based on prevention of mother-to-child HIV transmission regimen (5%-40%), return of test results (41%), enrollment in HIV care (52%), and ART initiation (54%). We conducted sensitivity analyses to model the impact of key variables and applied the model to specific country examples. Adding HIV testing at birth would increase the number of infants on ART by 204% by age 18 months. The greatest increase is seen in early ART initiations (543% by age 3 months). The increase would lead to a corresponding increase in survival at 12 months of age, with 5108 fewer infant deaths (44,550, versus 49,658). Adding HIV testing at birth has the potential to improve the number and timing of ART initiation of HIV-infected infants, leading to a decrease in infant mortality. Using this model, countries should investigate a combination of HIV testing at birth and during the early infant period.

Regression analysis of current-status data: an application to breast-feeding.

PubMed

Grummer-strawn, L M

1993-09-01

"Although techniques for calculating mean survival time from current-status data are well known, their use in multiple regression models is somewhat troublesome. Using data on current breast-feeding behavior, this article considers a number of techniques that have been suggested in the literature, including parametric, nonparametric, and semiparametric models as well as the application of standard schedules. Models are tested in both proportional-odds and proportional-hazards frameworks....I fit [the] models to current status data on breast-feeding from the Demographic and Health Survey (DHS) in six countries: two African (Mali and Ondo State, Nigeria), two Asian (Indonesia and Sri Lanka), and two Latin American (Colombia and Peru)." excerpt

HB06 : Field Validation of Realtime Predictions of Surfzone Waves and Currents

NASA Astrophysics Data System (ADS)

Guza, R. T.; O'Reilly, W. C.; Feddersen, F.

2006-12-01

California shorelines can be contaminated by the discharge of polluted streams and rivers onto the beach face or into the surf zone. Management decisions (for example, beach closures) can be assisted by accurate characterization of the waves and currents that transport and mix these pollutants. A real-time, operational waves and alongshore current model, developed for a 5 km alongshore reach at Huntington Beach (http://cdip.ucsd.edu/hb06/), will be tested for a month during Fall 2006 as part of the HB06 field experiment. The model has two components: prediction of incident waves immediately seaward of the surf zone, and the transformation of breaking waves across the surf zone. The California Safe Boating Network Model (O'Reilly et al., California World Ocean Conference, 2006) is used to estimate incident wave properties. This regional wave model accounts for blocking and refraction by offshore islands and shoals, and variation of the shoreline orientation. At Huntington Beach, the network model uses four buoys exposed to the deep ocean to estimate swell, and four nearby buoys to estimate locally generated seas. The model predictions will be compared with directional wave buoy observations in 22 m depth, 1 km from the shore. The computationally fast model for surfzone waves and breaking-wave driven alongshore currents, appropriate for random waves on beaches with simple bathymetry, is based on concepts developed and tested by Ed Thornton and his colleagues over the last 30 years. Modeled alongshore currents at Huntington Beach, with incident waves predicted by the Network model, will be compared with waves and currents observed during HB06 along a transect extending from 4 m depth to the shoreline. Support from the California Coastal Conservancy, NOAA, and ONR is gratefully acknowledged.

Depression and Delinquency Covariation in an Accelerated Longitudinal Sample of Adolescents

ERIC Educational Resources Information Center

Kofler, Michael J.; McCart, Michael R.; Zajac, Kristyn; Ruggiero, Kenneth J.; Saunders, Benjamin E.; Kilpatrick, Dean G.

2011-01-01

Objectives: The current study tested opposing predictions stemming from the failure and acting out theories of depression-delinquency covariation. Method: Participants included a nationwide longitudinal sample of adolescents (N = 3,604) ages 12 to 17. Competing models were tested with cohort-sequential latent growth curve modeling to determine…

Aporrectodea caliginosa, a relevant earthworm species for a posteriori pesticide risk assessment: current knowledge and recommendations for culture and experimental design.

PubMed

Bart, Sylvain; Amossé, Joël; Lowe, Christopher N; Mougin, Christian; Péry, Alexandre R R; Pelosi, Céline

2018-06-21

Ecotoxicological tests with earthworms are widely used and are mandatory for the risk assessment of pesticides prior to registration and commercial use. The current model species for standardized tests is Eisenia fetida or Eisenia andrei. However, these species are absent from agricultural soils and often less sensitive to pesticides than other earthworm species found in mineral soils. To move towards a better assessment of pesticide effects on non-target organisms, there is a need to perform a posteriori tests using relevant species. The endogeic species Aporrectodea caliginosa (Savigny, 1826) is representative of cultivated fields in temperate regions and is suggested as a relevant model test species. After providing information on its taxonomy, biology, and ecology, we reviewed current knowledge concerning its sensitivity towards pesticides. Moreover, we highlighted research gaps and promising perspectives. Finally, advice and recommendations are given for the establishment of laboratory cultures and experiments using this soil-dwelling earthworm species.

Cost-Effectiveness of Opt-Out Chlamydia Testing for High-Risk Young Women in the U.S.

PubMed

Owusu-Edusei, Kwame; Hoover, Karen W; Gift, Thomas L

2016-08-01

In spite of chlamydia screening recommendations, U.S. testing coverage continues to be low. This study explored the cost-effectiveness of a patient-directed, universal, opportunistic Opt-Out Testing strategy (based on insurance coverage, healthcare utilization, and test acceptance probabilities) for all women aged 15-24 years compared with current Risk-Based Screening (30% coverage) from a societal perspective. Based on insurance coverage (80%); healthcare utilization (83%); and test acceptance (75%), the proposed Opt-Out Testing strategy would have an expected annual testing coverage of approximately 50% for sexually active women aged 15-24 years. A basic compartmental heterosexual transmission model was developed to account for population-level transmission dynamics. Two groups were assumed based on self-reported sexual activity. All model parameters were obtained from the literature. Costs and benefits were tracked over a 50-year period. The relative sensitivity of the estimated incremental cost-effectiveness ratios to the variables/parameters was determined. This study was conducted in 2014-2015. Based on the model, the Opt-Out Testing strategy decreased the overall chlamydia prevalence by >55% (2.7% to 1.2%). The Opt-Out Testing strategy was cost saving compared with the current Risk-Based Screening strategy. The estimated incremental cost-effectiveness ratio was most sensitive to the female pre-opt out prevalence, followed by the probability of female sequelae and discount rate. The proposed Opt-Out Testing strategy was cost saving, improving health outcomes at a lower net cost than current testing. However, testing gaps would remain because many women might not have health insurance coverage, or not utilize health care. Published by Elsevier Inc.

Rethinking developmental toxicity testing: Evolution or revolution?

PubMed

Scialli, Anthony R; Daston, George; Chen, Connie; Coder, Prägati S; Euling, Susan Y; Foreman, Jennifer; Hoberman, Alan M; Hui, Julia; Knudsen, Thomas; Makris, Susan L; Morford, LaRonda; Piersma, Aldert H; Stanislaus, Dinesh; Thompson, Kary E

2018-06-01

Current developmental toxicity testing adheres largely to protocols suggested in 1966 involving the administration of test compound to pregnant laboratory animals. After more than 50 years of embryo-fetal development testing, are we ready to consider a different approach to human developmental toxicity testing? A workshop was held under the auspices of the Developmental and Reproductive Toxicology Technical Committee of the ILSI Health and Environmental Sciences Institute to consider how we might design developmental toxicity testing if we started over with 21st century knowledge and techniques (revolution). We first consider what changes to the current protocols might be recommended to make them more predictive for human risk (evolution). The evolutionary approach includes modifications of existing protocols and can include humanized models, disease models, more accurate assessment and testing of metabolites, and informed approaches to dose selection. The revolution could start with hypothesis-driven testing where we take what we know about a compound or close analog and answer specific questions using targeted experimental techniques rather than a one-protocol-fits-all approach. Central to the idea of hypothesis-driven testing is the concept that testing can be done at the level of mode of action. It might be feasible to identify a small number of key events at a molecular or cellular level that predict an adverse outcome and for which testing could be performed in vitro or in silico or, rarely, using limited in vivo models. Techniques for evaluating these key events exist today or are in development. Opportunities exist for refining and then replacing current developmental toxicity testing protocols using techniques that have already been developed or are within reach. © 2018 The Authors. Birth Defects Research Published by Wiley Periodicals, Inc.

A Power Hardware-in-the-Loop Platform with Remote Distribution Circuit Cosimulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palmintier, Bryan; Lundstrom, Blake; Chakraborty, Sudipta

2015-04-01

This paper demonstrates the use of a novel cosimulation architecture that integrates hardware testing using Power Hardware-in-the-Loop (PHIL) with larger-scale electric grid models using off-the-shelf, non-PHIL software tools. This architecture enables utilities to study the impacts of emerging energy technologies on their system and manufacturers to explore the interactions of new devices with existing and emerging devices on the power system, both without the need to convert existing grid models to a new platform or to conduct in-field trials. The paper describes an implementation of this architecture for testing two residential-scale advanced solar inverters at separate points of common coupling.more » The same hardware setup is tested with two different distribution feeders (IEEE 123 and 8500 node test systems) modeled using GridLAB-D. In addition to simplifying testing with multiple feeders, the architecture demonstrates additional flexibility with hardware testing in one location linked via the Internet to software modeling in a remote location. In testing, inverter current, real and reactive power, and PCC voltage are well captured by the co-simulation platform. Testing of the inverter advanced control features is currently somewhat limited by the software model time step (1 sec) and tested communication latency (24 msec). Overshoot induced oscillations are observed with volt/VAR control delays of 0 and 1.5 sec, while 3.4 sec and 5.5 sec delays produced little or no oscillation. These limitations could be overcome using faster modeling and communication within the same co-simulation architecture.« less

Alternative models in developmental toxicology.

PubMed

Lee, Hyung-yul; Inselman, Amy L; Kanungo, Jyotshnabala; Hansen, Deborah K

2012-02-01

In light of various pressures, toxicologists have been searching for alternative methods for safety testing of chemicals. According to a recent policy in the European Union (Regulation, Evaluation Authorisation and Restriction of Chemicals, REACH), it has been estimated that over the next twelve to fifteen years, approximately 30,000 chemicals may need to be tested for safety, and under current guidelines such testing would require the use of approximately 7.2 million laboratory animals [ Hofer et al. 2004 ]. It has also been estimated that over 80% of all animals used for safety testing under REACH legislation would be used for examining reproductive and developmental toxicity [Hofer et al., 2004]. In addition to REACH initiatives, it has been estimated that out of 5,000 to 10,000 new drug entities that a pharmaceutical company may start with, only one is finally approved by the Food and Drug Administration at a cost of over one billion dollars [ Garg et al. 2011 ]. A large portion of this cost is due to animal testing. Therefore, both the pharmaceutical and chemical industries are interested in using alternative models and in vitro tests for safety testing. This review will examine the current state of three alternative models - whole embryo culture (WEC), the mouse embryonic stem cell test (mEST), and zebrafish. Each of these alternatives will be reviewed, and advantages and disadvantages of each model will be discussed. These models were chosen because they are the models most commonly used and would appear to have the greatest potential for future applications in developmental toxicity screening and testing.

Fit Assessment of N95 Filtering-Facepiece Respirators in the U.S. Centers for Disease Control and Prevention Strategic National Stockpile.

PubMed

Bergman, Michael; Zhuang, Ziqing; Brochu, Elizabeth; Palmiero, Andrew

National Institute for Occupational Safety and Health (NIOSH)-approved N95 filtering-facepiece respirators (FFR) are currently stockpiled by the U.S. Centers for Disease Control and Prevention (CDC) for emergency deployment to healthcare facilities in the event of a widespread emergency such as an influenza pandemic. This study assessed the fit of N95 FFRs purchased for the CDC Strategic National Stockpile. The study addresses the question of whether the fit achieved by specific respirator sizes relates to facial size categories as defined by two NIOSH fit test panels. Fit test data were analyzed from 229 test subjects who performed a nine-donning fit test on seven N95 FFR models using a quantitative fit test protocol. An initial respirator model selection process was used to determine if the subject could achieve an adequate fit on a particular model; subjects then tested the adequately fitting model for the nine-donning fit test. Only data for models which provided an adequate initial fit (through the model selection process) for a subject were analyzed for this study. For the nine-donning fit test, six of the seven respirator models accommodated the fit of subjects (as indicated by geometric mean fit factor > 100) for not only the intended NIOSH bivariate and PCA panel sizes corresponding to the respirator size, but also for other panel sizes which were tested for each model. The model which showed poor performance may not be accurately represented because only two subjects passed the initial selection criteria to use this model. Findings are supportive of the current selection of facial dimensions for the new NIOSH panels. The various FFR models selected for the CDC Strategic National Stockpile provide a range of sizing options to fit a variety of facial sizes.

Fit Assessment of N95 Filtering-Facepiece Respirators in the U.S. Centers for Disease Control and Prevention Strategic National Stockpile

PubMed Central

Bergman, Michael; Zhuang, Ziqing; Brochu, Elizabeth; Palmiero, Andrew

2016-01-01

National Institute for Occupational Safety and Health (NIOSH)-approved N95 filtering-facepiece respirators (FFR) are currently stockpiled by the U.S. Centers for Disease Control and Prevention (CDC) for emergency deployment to healthcare facilities in the event of a widespread emergency such as an influenza pandemic. This study assessed the fit of N95 FFRs purchased for the CDC Strategic National Stockpile. The study addresses the question of whether the fit achieved by specific respirator sizes relates to facial size categories as defined by two NIOSH fit test panels. Fit test data were analyzed from 229 test subjects who performed a nine-donning fit test on seven N95 FFR models using a quantitative fit test protocol. An initial respirator model selection process was used to determine if the subject could achieve an adequate fit on a particular model; subjects then tested the adequately fitting model for the nine-donning fit test. Only data for models which provided an adequate initial fit (through the model selection process) for a subject were analyzed for this study. For the nine-donning fit test, six of the seven respirator models accommodated the fit of subjects (as indicated by geometric mean fit factor > 100) for not only the intended NIOSH bivariate and PCA panel sizes corresponding to the respirator size, but also for other panel sizes which were tested for each model. The model which showed poor performance may not be accurately represented because only two subjects passed the initial selection criteria to use this model. Findings are supportive of the current selection of facial dimensions for the new NIOSH panels. The various FFR models selected for the CDC Strategic National Stockpile provide a range of sizing options to fit a variety of facial sizes. PMID:26877587

Design Science Research toward Designing/Prototyping a Repeatable Model for Testing Location Management (LM) Algorithms for Wireless Networking

ERIC Educational Resources Information Center

Peacock, Christopher

2012-01-01

The purpose of this research effort was to develop a model that provides repeatable Location Management (LM) testing using a network simulation tool, QualNet version 5.1 (2011). The model will provide current and future protocol developers a framework to simulate stable protocol environments for development. This study used the Design Science…

The Pittsburgh Cervical Cancer Screening Model: a risk assessment tool.

PubMed

Austin, R Marshall; Onisko, Agnieszka; Druzdzel, Marek J

2010-05-01

Evaluation of cervical cancer screening has grown increasingly complex with the introduction of human papillomavirus (HPV) vaccination and newer screening technologies approved by the US Food and Drug Administration. To create a unique Pittsburgh Cervical Cancer Screening Model (PCCSM) that quantifies risk for histopathologic cervical precancer (cervical intraepithelial neoplasia [CIN] 2, CIN3, and adenocarcinoma in situ) and cervical cancer in an environment predominantly using newer screening technologies. The PCCSM is a dynamic Bayesian network consisting of 19 variables available in the laboratory information system, including patient history data (most recent HPV vaccination data), Papanicolaou test results, high-risk HPV results, procedure data, and histopathologic results. The model's graphic structure was based on the published literature. Results from 375 441 patient records from 2005 through 2008 were used to build and train the model. Additional data from 45 930 patients were used to test the model. The PCCSM compares risk quantitatively over time for histopathologically verifiable CIN2, CIN3, adenocarcinoma in situ, and cervical cancer in screened patients for each current cytology result category and for each HPV result. For each current cytology result, HPV test results affect risk; however, the degree of cytologic abnormality remains the largest positive predictor of risk. Prior history also alters the CIN2, CIN3, adenocarcinoma in situ, and cervical cancer risk for patients with common current cytology and HPV test results. The PCCSM can also generate negative risk projections, estimating the likelihood of the absence of histopathologic CIN2, CIN3, adenocarcinoma in situ, and cervical cancer in screened patients. The PCCSM is a dynamic Bayesian network that computes quantitative cervical disease risk estimates for patients undergoing cervical screening. Continuously updatable with current system data, the PCCSM provides a new tool to monitor cervical disease risk in the evolving postvaccination era.

Lightning induced currents in aircraft wiring using low level injection techniques

NASA Technical Reports Server (NTRS)

Stevens, E. G.; Jordan, D. T.

1991-01-01

Various techniques were studied to predict the transient current induced into aircraft wiring bundles as a result of an aircraft lightning strike. A series of aircraft measurements were carried out together with a theoretical analysis using computer modeling. These tests were applied to various aircraft and also to specially constructed cylinders installed within coaxial return conductor systems. Low level swept frequency CW (carrier waves), low level transient and high level transient injection tests were applied to the aircraft and cylinders. Measurements were made to determine the transfer function between the aircraft drive current and the resulting skin currents and currents induced on the internal wiring. The full threat lightning induced transient currents were extrapolated from the low level data using Fourier transform techniques. The aircraft and cylinders used were constructed from both metallic and CFC (carbon fiber composite) materials. The results show the pulse stretching phenomenon which occurs for CFC materials due to the diffusion of the lightning current through carbon fiber materials. Transmission Line Matrix modeling techniques were used to compare theoretical and measured currents.

The storm time ring current dynamics and response to CMEs and CIRs using Van Allen Probes observations and CIMI simulations

NASA Astrophysics Data System (ADS)

Mouikis, Christopher; Bingham, Samuel; Kistler, Lynn; Spence, Harlan; Gkioulidou, Matina

2017-04-01

The ring current responds differently to the different solar and interplanetary storm drivers such as coronal mass injections, (CME's), and co-rotating interaction regions (CIR's). Using Van Allen Probes observations, we develop an empirical ring current model of the ring current pressure, the pressure anisotropy and the current density development during the storm phases for both types of storm drivers and for all MLTs inside L 6. Delineating the differences in the ring current development between these two drivers will aid our understanding of the ring current dynamics. We find that during the storm main phase most of the ring current pressure in the pre-midnight inner magnetosphere is contributed by particles on open drift paths that cause the development of a strong partial ring current that causes most of the main phase Dst drop. These particles can reach as deep as L 2 and their pressure compares to the local magnetic field pressure as deep as L 3. During the recovery phase, if these particles are not lost at the magnetopause, will become trapped and will contribute to the symmetric ring current. However, the largest difference between the CME and CIR ring current responses during the storm main and early recovery phases is caused by how the 15 - 60 keV O+ responds to these drivers. This empirical model is compared to the results of CIMI simulations of a CMEs and a CIRs where the model input is comprised of the superposed epoch solar wind conditions of the storms that comprise the empirical model. Different inner magnetosphere boundary conditions are tested in order to match the empirical model results. Comparing the model and simulation results improves our understanding of the ring current dynamics as part of the highly coupled inner magnetosphere system. In addition, within the framework of this empirical model, the prediction of the EMIC wave generation linear theory is tested using the observed plasma parameters and comparing with the observations of EMIC waves.

A Risk-Based Approach for Aerothermal/TPS Analysis and Testing

NASA Technical Reports Server (NTRS)

Wright, Michael J.; Grinstead, Jay H.; Bose, Deepak

2007-01-01

The current status of aerothermal and thermal protection system modeling for civilian entry missions is reviewed. For most such missions, the accuracy of our simulations is limited not by the tools and processes currently employed, but rather by reducible deficiencies in the underlying physical models. Improving the accuracy of and reducing the uncertainties in these models will enable a greater understanding of the system level impacts of a particular thermal protection system and of the system operation and risk over the operational life of the system. A strategic plan will be laid out by which key modeling deficiencies can be identified via mission-specific gap analysis. Once these gaps have been identified, the driving component uncertainties are determined via sensitivity analyses. A Monte-Carlo based methodology is presented for physics-based probabilistic uncertainty analysis of aerothermodynamics and thermal protection system material response modeling. These data are then used to advocate for and plan focused testing aimed at reducing key uncertainties. The results of these tests are used to validate or modify existing physical models. Concurrently, a testing methodology is outlined for thermal protection materials. The proposed approach is based on using the results of uncertainty/sensitivity analyses discussed above to tailor ground testing so as to best identify and quantify system performance and risk drivers. A key component of this testing is understanding the relationship between the test and flight environments. No existing ground test facility can simultaneously replicate all aspects of the flight environment, and therefore good models for traceability to flight are critical to ensure a low risk, high reliability thermal protection system design. Finally, the role of flight testing in the overall thermal protection system development strategy is discussed.

Differential roles of two delayed rectifier potassium currents in regulation of ventricular action potential duration and arrhythmia susceptibility.

PubMed

Devenyi, Ryan A; Ortega, Francis A; Groenendaal, Willemijn; Krogh-Madsen, Trine; Christini, David J; Sobie, Eric A

2017-04-01

Arrhythmias result from disruptions to cardiac electrical activity, although the factors that control cellular action potentials are incompletely understood. We combined mathematical modelling with experiments in heart cells from guinea pigs to determine how cellular electrical activity is regulated. A mismatch between modelling predictions and the experimental results allowed us to construct an improved, more predictive mathematical model. The balance between two particular potassium currents dictates how heart cells respond to perturbations and their susceptibility to arrhythmias. Imbalances of ionic currents can destabilize the cardiac action potential and potentially trigger lethal cardiac arrhythmias. In the present study, we combined mathematical modelling with information-rich dynamic clamp experiments to determine the regulation of action potential morphology in guinea pig ventricular myocytes. Parameter sensitivity analysis was used to predict how changes in ionic currents alter action potential duration, and these were tested experimentally using dynamic clamp, a technique that allows for multiple perturbations to be tested in each cell. Surprisingly, we found that a leading mathematical model, developed with traditional approaches, systematically underestimated experimental responses to dynamic clamp perturbations. We then re-parameterized the model using a genetic algorithm, which allowed us to estimate ionic current levels in each of the cells studied. This unbiased model adjustment consistently predicted an increase in the rapid delayed rectifier K + current and a drastic decrease in the slow delayed rectifier K + current, and this prediction was validated experimentally. Subsequent simulations with the adjusted model generated the clinically relevant prediction that the slow delayed rectifier is better able to stabilize the action potential and suppress pro-arrhythmic events than the rapid delayed rectifier. In summary, iterative coupling of simulations and experiments enabled novel insight into how the balance between cardiac K + currents influences ventricular arrhythmia susceptibility. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

Modeling of Elastic Collisions between High Energy and Slow Neutral Atoms

DTIC Science & Technology

2015-07-01

cylindrical test cell, and the currents on the four different electrodes-Inner Cylinder , Exit Plate, Back Aperture, and Collector Plat~were measured...Inner Cylinder electrode. Nevertheless, the neutral atom current to the Inner Cylinder electrode predicted by the VHS model is comparable to the...Figure 9. Normalized curre nt at the Inner Cylinder e lectrode. the point of collision. T he discrepancy in the Exit Plate neutral atom current is due to

Reduced Current Spread by Concentric Electrodes in Transcranial Electrical Stimulation (tES).

PubMed

Bortoletto, M; Rodella, C; Salvador, R; Miranda, P C; Miniussi, C

2016-01-01

We propose the use of a new montage for transcranial direct current stimulation (tDCS), called concentric electrodes tDCS (CE-tDCS), involving two concentric round electrodes that may improve stimulation focality. To test efficacy and focality of CE-tDCS, we modelled the current distribution and tested physiological effects on cortical excitability. Motor evoked potentials (MEPs) from first dorsal interosseous (FDI) and abductor digiti minimi (ADM) were recorded before and after the delivery of anodal, cathodal and sham stimulation on the FDI hotspot for 10 minutes. MEP amplitude of FDI increased after anodal-tDCS and decreased after cathodal-tDCS, supporting the efficacy of CE-tDCS in modulating cortical excitability. Moreover, modelled current distribution and no significant effects of stimulation on MEP amplitude of ADM suggest high focality of CE-tDCS. CE-tDCS may allow a better control of current distribution and may represent a novel tool for applying tDCS and other transcranial current stimulation approaches. Copyright © 2016 Elsevier Inc. All rights reserved.

Quality Test of Flexible Flat Cable (FFC) With Short Open Test Using Law Ohm Approach through Embedded Fuzzy Logic Based On Open Source Arduino Data Logger

NASA Astrophysics Data System (ADS)

Rohmanu, Ajar; Everhard, Yan

2017-04-01

A technological development, especially in the field of electronics is very fast. One of the developments in the electronics hardware device is Flexible Flat Cable (FFC), which serves as a media liaison between the main boards with other hardware parts. The production of Flexible Flat Cable (FFC) will go through the process of testing and measuring of the quality Flexible Flat Cable (FFC). Currently, the testing and measurement is still done manually by observing the Light Emitting Diode (LED) by the operator, so there were many problems. This study will be made of test quality Flexible Flat Cable (FFC) computationally utilize Open Source Embedded System. The method used is the measurement with Short Open Test method using Ohm’s Law approach to 4-wire (Kelvin) and fuzzy logic as a decision maker measurement results based on Open Source Arduino Data Logger. This system uses a sensor current INA219 as a sensor to read the voltage value thus obtained resistance value Flexible Flat Cable (FFC). To get a good system we will do the Black-box testing as well as testing the accuracy and precision with the standard deviation method. In testing the system using three models samples were obtained the test results in the form of standard deviation for the first model of 1.921 second model of 4.567 and 6.300 for the third model. While the value of the Standard Error of Mean (SEM) for the first model of the model 0.304 second at 0.736 and 0.996 of the third model. In testing this system, we will also obtain the average value of the measurement tolerance resistance values for the first model of - 3.50% 4.45% second model and the third model of 5.18% with the standard measurement of prisoners and improve productivity becomes 118.33%. From the results of the testing system is expected to improve the quality and productivity in the process of testing Flexible Flat Cable (FFC).

Sex-Specific Pathways to Early Puberty, Sexual Debut, and Sexual Risk Taking: Tests of an Integrated Evolutionary-Developmental Model

ERIC Educational Resources Information Center

James, Jenee; Ellis, Bruce J.; Schlomer, Gabriel L.; Garber, Judy

2012-01-01

The current study tested sex-specific pathways to early puberty, sexual debut, and sexual risk taking, as specified by an integrated evolutionary-developmental model of adolescent sexual development and behavior. In a prospective study of 238 adolescents (n = 129 girls and n = 109 boys) followed from approximately 12-18 years of age, we tested for…

Methods for data reduction and loads analysis of Space Shuttle Solid Rocket Booster model water impact tests

NASA Technical Reports Server (NTRS)

1976-01-01

The methodology used to predict full scale space shuttle solid rocket booster (SRB) water impact loads from scale model test data is described. Tests conducted included 12.5 inch and 120 inch diameter models of the SRB. Geometry and mass characteristics of the models were varied in each test series to reflect the current SRB baseline configuration. Nose first and tail first water entry modes were investigated with full-scale initial impact vertical velocities of 40 to 120 ft/sec, horizontal velocities of 0 to 60 ft/sec., and off-vertical angles of 0 to plus or minus 30 degrees. The test program included a series of tests with scaled atmospheric pressure.

The Multifaceted Role of Attachment during Preschool: Moderator of Its Indirect Effect on Empathy through Emotion Regulation

ERIC Educational Resources Information Center

Stefan, Catrinel A.; Avram, Julia

2018-01-01

The aims of the current study were (1) to replicate findings regarding the mediator role of emotion regulation (ER) between attachment and empathy; (2) to extend current knowledge by testing the moderator effect of ER on the relationship between attachment and empathy; and (3) to test an integrative moderated mediation model in which attachment…

Scaled Tank Test Design and Results for the Aquantis 2.5 MW Ocean Current Generation Device

DOE Data Explorer

Swales, Henry; Kils, Ole; Coakley, David B.; Sites, Eric; Mayer, Tyler

2015-06-03

Aquantis 2.5 MW Ocean Current Generation Device, Tow Tank Dynamic Rig Structural Analysis Results. This is the detailed documentation for scaled device testing in a tow tank, including models, drawings, presentations, cost of energy analysis, and structural analysis. This dataset also includes specific information on drivetrain, roller bearing, blade fabrication, mooring, and rotor characteristics.

Choosing a College Major: Factors that Might Influence the Way Students Make Decisions

ERIC Educational Resources Information Center

Lee, Wei-Chun Vanessa

2009-01-01

This current study investigated Janis and Mann's (1977) Conflict Model of Decision Making. Specifically, Janis and Mann's model was tested to examine decision-making styles (coping patterns) and students who either have already decided or who have yet to decide on their college major. Furthermore, the current study is aimed to expand Janis and…

Integrated Mecical Model (IMM) 4.0 Verification and Validation (VV) Testing (HRP IWS 2016)

NASA Technical Reports Server (NTRS)

Walton, M; Kerstman, E.; Arellano, J.; Boley, L.; Reyes, D.; Young, M.; Garcia, Y.; Saile, L.; Myers, J.

2016-01-01

Timeline, partial treatment, and alternate medications were added to the IMM to improve the fidelity of this model to enhance decision support capabilities. Using standard design reference missions, IMM VV testing compared outputs from the current operational IMM (v3) with those from the model with added functionalities (v4). These new capabilities were examined in a comparative, stepwise approach as follows: a) comparison of the current operational IMM v3 with the enhanced functionality of timeline alone (IMM 4.T), b) comparison of IMM 4.T with the timeline and partial treatment (IMM 4.TPT), and c) comparison of IMM 4.TPT with timeline, partial treatment and alternative medication (IMM 4.0).

Asymmetrical Capacitors for Propulsion

NASA Technical Reports Server (NTRS)

Canning, Francis X.; Melcher, Cory; Winet, Edwin

2004-01-01

Asymmetrical Capacitor Thrusters have been proposed as a source of propulsion. For over eighty years, it has been known that a thrust results when a high voltage is placed across an asymmetrical capacitor, when that voltage causes a leakage current to flow. However, there is surprisingly little experimental or theoretical data explaining this effect. This paper reports on the results of tests of several Asymmetrical Capacitor Thrusters (ACTs). The thrust they produce has been measured for various voltages, polarities, and ground configurations and their radiation in the VHF range has been recorded. These tests were performed at atmospheric pressure and at various reduced pressures. A simple model for the thrust was developed. The model assumed the thrust was due to electrostatic forces on the leakage current flowing across the capacitor. It was further assumed that this current involves charged ions which undergo multiple collisions with air. These collisions transfer momentum. All of the measured data was consistent with this model. Many configurations were tested, and the results suggest general design principles for ACTs to be used for a variety of purposes.

The Experimental Measurement of Aerodynamic Heating About Complex Shapes at Supersonic Mach Numbers

NASA Technical Reports Server (NTRS)

Neumann, Richard D.; Freeman, Delma C.

2011-01-01

In 2008 a wind tunnel test program was implemented to update the experimental data available for predicting protuberance heating at supersonic Mach numbers. For this test the Langley Unitary Wind Tunnel was also used. The significant differences for this current test were the advances in the state-of-the-art in model design, fabrication techniques, instrumentation and data acquisition capabilities. This current paper provides a focused discussion of the results of an in depth analysis of unique measurements of recovery temperature obtained during the test.

Underground Test Area Subproject Phase I Data Analysis Task. Volume VII - Tritium Transport Model Documentation Package

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

Volume VII of the documentation for the Phase I Data Analysis Task performed in support of the current Regional Flow Model, Transport Model, and Risk Assessment for the Nevada Test Site Underground Test Area Subproject contains the tritium transport model documentation. Because of the size and complexity of the model area, a considerable quantity of data was collected and analyzed in support of the modeling efforts. The data analysis task was consequently broken into eight subtasks, and descriptions of each subtask's activities are contained in one of the eight volumes that comprise the Phase I Data Analysis Documentation.

An Investigation of Sample Size Splitting on ATFIND and DIMTEST

ERIC Educational Resources Information Center

Socha, Alan; DeMars, Christine E.

2013-01-01

Modeling multidimensional test data with a unidimensional model can result in serious statistical errors, such as bias in item parameter estimates. Many methods exist for assessing the dimensionality of a test. The current study focused on DIMTEST. Using simulated data, the effects of sample size splitting for use with the ATFIND procedure for…

76 FR 33271 - Energy Conservation Program for Consumer Products: Decision and Order Granting a Waiver to...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-08

... authorizes the Secretary of Energy to prescribe test procedures that are reasonably designed to produce... conditions is met: (1) The petitioner's basic model contains one or more design characteristics that prevent..., BSH asserts, design characteristics of these models prevent testing according to the currently...

Robustness of Ability Estimation to Multidimensionality in CAST with Implications to Test Assembly

ERIC Educational Resources Information Center

Zhang, Yanwei; Nandakumar, Ratna

2006-01-01

Computer Adaptive Sequential Testing (CAST) is a test delivery model that combines features of the traditional conventional paper-and-pencil testing and item-based computerized adaptive testing (CAT). The basic structure of CAST is a panel composed of multiple testlets adaptively administered to examinees at different stages. Current applications…

Controllable Bidirectional dc Power Sources For Large Loads

NASA Technical Reports Server (NTRS)

Tripp, John S.; Daniels, Taumi S.

1995-01-01

System redesigned for greater efficiency, durability, and controllability. Modern electronically controlled dc power sources proposed to supply currents to six electromagnets used to position aerodynamic test model in wind tunnel. Six-phase bridge rectifier supplies load with large current at voltage of commanded magnitude and polarity. Current-feedback circuit includes current-limiting feature giving some protection against overload.

Wind Tunnel and Hover Performance Test Results for Multicopter UAS Vehicles

NASA Technical Reports Server (NTRS)

Russell, Carl R.; Jung, Jaewoo; Willink, Gina; Glasner, Brett

2016-01-01

There is currently a lack of published data for the performance of multicopter unmanned aircraft system (UAS) vehicles, such as quadcopters and octocopters, often referred to collectively as drones. With the rapidly increasing popularity of multicopter UAS, there is interest in better characterizing the performance of this type of aircraft. By studying the performance of currently available vehicles, it will be possible to develop models for vehicles at this scale that can accurately predict performance and model trajectories. This paper describes a wind tunnel test that was recently performed in the U.S. Army's 7- by 10-ft Wind Tunnel at NASA Ames Research Center. During this wind tunnel entry, five multicopter UAS vehicles were tested to determine forces and moments as well as electrical power as a function of wind speed, rotor speed, and vehicle attitude. The test is described here in detail, and a selection of the key results from the test is presented.

Joint Live Fire (JLF) Final Report for Instrumentation for Local Accelerative Loading

DTIC Science & Technology

2016-07-22

Comparison with Pretest Prediction ................................................................................... 60 d. Lessons Learned...test designs and results prior to full-scale testing. Correlating simulation to test data can aid in increasing confidence in the models to further...test and test-to-simulation with the current instrumentation used during testing. Recent advances in accelerometer design must be evaluated and

Neurovirulence safety testing of mumps vaccines--historical perspective and current status.

PubMed

Rubin, S A; Afzal, M A

2011-04-05

Many live, attenuated viral vaccines are derived from wild type viruses with known neurovirulent properties. To assure the absence of residual neurotoxicity, pre-clinical neurovirulence safety testing of candidate vaccines is performed. For mumps virus, a highly neurotropic virus, neurovirulence safety testing is performed in monkeys. However, laboratory studies suggest an inability of this test to correctly discern among virus strains of varying neurovirulence potential in man, and, further, some vaccines found to be neuroattenuated in monkeys were later found to be neurovirulent in humans when administered in large numbers. Over the past decade, concerted efforts have been made to replace monkey-based neurovirulence safety testing with more informative, alternative methods. This review summarizes the current status of mumps vaccine neurovirulence safety testing and insights into models currently approved and those under development. Published by Elsevier Ltd.

Summary of Current and Future MSFC International Space Station Environmental Control and Life Support System Activities

NASA Technical Reports Server (NTRS)

Ray, Charles D.; Carrasquillo, Robyn L.; Minton-Summers, Silvia

1997-01-01

This paper provides a summary of current work accomplished under technical task agreement (TTA) by the Marshall Space Flight Center (MSFC) regarding the Environmental Control and Life Support System (ECLSS) as well as future planning activities in support of the International Space Station (ISS). Current activities include ECLSS computer model development, component design and development, subsystem integrated system testing, life testing, and government furnished equipment delivered to the ISS program. A long range plan for the MSFC ECLSS test facility is described whereby the current facility would be upgraded to support integrated station ECLSS operations. ECLSS technology development efforts proposed to be performed under the Advanced Engineering Technology Development (AETD) program are also discussed.

Robust constraint on cosmic textures from the cosmic microwave background.

PubMed

Feeney, Stephen M; Johnson, Matthew C; Mortlock, Daniel J; Peiris, Hiranya V

2012-06-15

Fluctuations in the cosmic microwave background (CMB) contain information which has been pivotal in establishing the current cosmological model. These data can also be used to test well-motivated additions to this model, such as cosmic textures. Textures are a type of topological defect that can be produced during a cosmological phase transition in the early Universe, and which leave characteristic hot and cold spots in the CMB. We apply bayesian methods to carry out a rigorous test of the texture hypothesis, using full-sky data from the Wilkinson Microwave Anisotropy Probe. We conclude that current data do not warrant augmenting the standard cosmological model with textures. We rule out at 95% confidence models that predict more than 6 detectable cosmic textures on the full sky.

Influence of backup bearings and support structure dynamics on the behavior of rotors with active supports

NASA Technical Reports Server (NTRS)

Flowers, George T.

1994-01-01

Progress over the past year includes the following: A simplified rotor model with a flexible shaft and backup bearings has been developed. A simple rotor model which includes a flexible disk and bearings with clearance has been developed and the dynamics of the model investigated. A rotor model based upon the T-501 engine has been developed which includes backup bearing effects. Parallel simulation runs are being conducted using an ANSYS based finite element model of the T-501. The magnetic bearing test rig is currently floating and dynamics/control tests are being conducted. A paper has been written that documents the work using the T-501 engine model. Work has continued with the simplified model. The finite element model is currently being modified to include the effects of foundation dynamics. A literature search for material on foil bearings has been conducted. A finite element model is being developed for a magnetic bearing in series with a foil backup bearing.

Constraining Roche-Lobe Overflow Models Using the Hot-Subdwarf Wide Binary Population

NASA Astrophysics Data System (ADS)

Vos, Joris; Vučković, Maja

2017-12-01

One of the important issues regarding the final evolution of stars is the impact of binarity. A rich zoo of peculiar, evolved objects are born from the interaction between the loosely bound envelope of a giant, and the gravitational pull of a companion. However, binary interactions are not understood from first principles, and the theoretical models are subject to many assumptions. It is currently agreed upon that hot subdwarf stars can only be formed through binary interaction, either through common envelope ejection or stable Roche-lobe overflow (RLOF) near the tip of the red giant branch (RGB). These systems are therefore an ideal testing ground for binary interaction models. With our long term study of wide hot subdwarf (sdB) binaries we aim to improve our current understanding of stable RLOF on the RGB by comparing the results of binary population synthesis studies with the observed population. In this article we describe the current model and possible improvements, and which observables can be used to test different parts of the interaction model.

A study on seismic behavior of pile foundations of bridge abutment on liquefiable ground through shaking table tests

NASA Astrophysics Data System (ADS)

Nakata, Mitsuhiko; Tanimoto, Shunsuke; Ishida, Shuichi; Ohsumi, Michio; Hoshikuma, Jun-ichi

2017-10-01

There is risk of bridge foundations to be damaged by liquefaction-induced lateral spreading of ground. Once bridge foundations have been damaged, it takes a lot of time for restoration. Therefore, it is important to assess the seismic behavior of the foundations on liquefiable ground appropriately. In this study, shaking table tests of models on a scale of 1/10 were conducted at the large scale shaking table in Public Works Research Institute, Japan, to investigate the seismic behavior of pile-supported bridge abutment on liquefiable ground. The shaking table tests were conducted for three types of model. Two are models of existing bridge which was built without design for liquefaction and the other is a model of bridge which was designed based on the current Japanese design specifications for highway bridges. As a result, the bending strains of piles of the abutment which were designed based on the current design specifications were less than those of the existing bridge.

Pressurization of cryogens - A review of current technology and its applicability to low-gravity conditions

NASA Technical Reports Server (NTRS)

Van Dresar, N. T.

1992-01-01

A review of technology, history, and current status for pressurized expulsion of cryogenic tankage is presented. Use of tank pressurization to expel cryogenic fluid will continue to be studied for future spacecraft applications over a range of operating conditions in the low-gravity environment. The review examines experimental test results and analytical model development for quiescent and agitated conditions in normal-gravity followed by a discussion of pressurization and expulsion in low-gravity. Validated, 1-D, finite difference codes exist for the prediction of pressurant mass requirements within the range of quiescent normal-gravity test data. To date, the effects of liquid sloshing have been characterized by tests in normal-gravity, but analytical models capable of predicting pressurant gas requirements remain unavailable. Efforts to develop multidimensional modeling capabilities in both normal and low-gravity have recently occurred. Low-gravity cryogenic fluid transfer experiments are needed to obtain low-gravity pressurized expulsion data. This data is required to guide analytical model development and to verify code performance.

Pressurization of cryogens: A review of current technology and its applicability to low-gravity conditions

NASA Technical Reports Server (NTRS)

Vandresar, N. T.

1992-01-01

A review of technology, history, and current status for pressurized expulsion of cryogenic tankage is presented. Use of tank pressurization to expel cryogenic fluids will continue to be studied for future spacecraft applications over a range of operating conditions in the low-gravity environment. The review examines experimental test results and analytical model development for quiescent and agitated conditions in normal-gravity, followed by a discussion of pressurization and expulsion in low-gravity. Validated, 1-D, finite difference codes exist for the prediction of pressurant mass requirements within the range of quiescent normal-gravity test data. To date, the effects of liquid sloshing have been characterized by tests in normal-gravity, but analytical models capable of predicting pressurant gas requirements remain unavailable. Efforts to develop multidimensional modeling capabilities in both normal and low-gravity have recently occurred. Low-gravity cryogenic fluid transfer experiments are needed to obtain low-gravity pressurized expulsion data. This data is required to guide analytical model development and to verify code performance.

Integrated research in constitutive modelling at elevated temperatures, part 2

NASA Technical Reports Server (NTRS)

Haisler, W. E.; Allen, D. H.

1986-01-01

Four current viscoplastic models are compared experimentally with Inconel 718 at 1100 F. A series of tests were performed to create a sufficient data base from which to evaluate material constants. The models used include Bodner's anisotropic model; Krieg, Swearengen, and Rhode's model; Schmidt and Miller's model; and Walker's exponential model.

Final Report on Jobin Yvon Contained Inductively Coupled Plasma Emission Spectrometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pennebaker, F.M.

2003-03-17

A new Inductively Coupled Plasma -- Emission Spectrometer (ICP-ES) was recently purchased and installed in Lab B-147/151 at SRTC. The contained JY Model Ultima 170-C ICP-ES has been tested and compared to current ADS ICP-ES instrumentation. The testing has included both performance tests to evaluate instrumental ability, and the measurement of matrix standards commonly analyzed by ICP-ES at Savannah River. In developing operating procedures for this instrument, we have implemented the use of internal standards and off-peak background subtraction. Both of these techniques are recommended by EPA SW-846 ICP-ES methods and are common to current ICP-ES operations. Based on themore » testing and changes, the JY Model Ultima 170-C ICP-ES provides improved performance for elemental analysis of radioactive samples in the Analytical Development Section.« less

Recent Achievements of the Collaboratory for the Study of Earthquake Predictability

NASA Astrophysics Data System (ADS)

Jackson, D. D.; Liukis, M.; Werner, M. J.; Schorlemmer, D.; Yu, J.; Maechling, P. J.; Zechar, J. D.; Jordan, T. H.

2015-12-01

Maria Liukis, SCEC, USC; Maximilian Werner, University of Bristol; Danijel Schorlemmer, GFZ Potsdam; John Yu, SCEC, USC; Philip Maechling, SCEC, USC; Jeremy Zechar, Swiss Seismological Service, ETH; Thomas H. Jordan, SCEC, USC, and the CSEP Working Group The Collaboratory for the Study of Earthquake Predictability (CSEP) supports a global program to conduct prospective earthquake forecasting experiments. CSEP testing centers are now operational in California, New Zealand, Japan, China, and Europe with 435 models under evaluation. The California testing center, operated by SCEC, has been operational since Sept 1, 2007, and currently hosts 30-minute, 1-day, 3-month, 1-year and 5-year forecasts, both alarm-based and probabilistic, for California, the Western Pacific, and worldwide. We have reduced testing latency, implemented prototype evaluation of M8 forecasts, and are currently developing formats and procedures to evaluate externally-hosted forecasts and predictions. These efforts are related to CSEP support of the USGS program in operational earthquake forecasting and a DHS project to register and test external forecast procedures from experts outside seismology. A retrospective experiment for the 2010-2012 Canterbury earthquake sequence has been completed, and the results indicate that some physics-based and hybrid models outperform purely statistical (e.g., ETAS) models. The experiment also demonstrates the power of the CSEP cyberinfrastructure for retrospective testing. Our current development includes evaluation strategies that increase computational efficiency for high-resolution global experiments, such as the evaluation of the Global Earthquake Activity Rate (GEAR) model. We describe the open-source CSEP software that is available to researchers as they develop their forecast models (http://northridge.usc.edu/trac/csep/wiki/MiniCSEP). We also discuss applications of CSEP infrastructure to geodetic transient detection and how CSEP procedures are being adapted to ground motion prediction experiments.

Exact simulation of integrate-and-fire models with exponential currents.

PubMed

Brette, Romain

2007-10-01

Neural networks can be simulated exactly using event-driven strategies, in which the algorithm advances directly from one spike to the next spike. It applies to neuron models for which we have (1) an explicit expression for the evolution of the state variables between spikes and (2) an explicit test on the state variables that predicts whether and when a spike will be emitted. In a previous work, we proposed a method that allows exact simulation of an integrate-and-fire model with exponential conductances, with the constraint of a single synaptic time constant. In this note, we propose a method, based on polynomial root finding, that applies to integrate-and-fire models with exponential currents, with possibly many different synaptic time constants. Models can include biexponential synaptic currents and spike-triggered adaptation currents.

Validating a Finite Element Model of a Structure Subjected to Mine Blast with Experimental Modal Analysis

DTIC Science & Technology

2017-11-01

The Under-body Blast Methodology (UBM) for the Test and Evaluation (T&E) program was established to provide a capability for the US Army Test and... Evaluation Command to assess the vulnerability of vehicles to under-body blast. Finite element (FE) models are part of the current UBM for T&E methodology...Methodology (UBM) for the Test and Evaluation (T&E) program was established to provide a capability for the US Army Test and Evaluation Command

In-Space Transportation with Tethers

NASA Technical Reports Server (NTRS)

Lorenzini, Enrico; Estes, Robert D.; Cosmo, Mario L.

1998-01-01

The annual report covers the research conducted on the following topics related to the use of spaceborne tethers for in-space transportation: ProSEDS tether modeling (current collection analyses, influence of a varying tether temperature); proSEDS mission analysis and system dynamics (tether thermal model, thermo-electro-dynamics integrated simulations); proSEDS-tether development and testing (tether requirements, deployment test plan, tether properties testing, deployment tests); and tethers for reboosting the space-based laser (mission analysis, tether system preliminary design, evaluation of attitude constraints).

FOCUS: A Model of Sensemaking

DTIC Science & Technology

2007-05-01

of the current project was to unpack and develop the concept of sensemaking, principally by developing and testing a cognitive model of the processes...themselves. In Year 2, new Cognitive Task Analysis data collection methods were developed and used to further test the model. Cognitive Task Analysis is a...2004) to examine the phenomenon of "sensemaking," a concept initially formulated by Weick (1995), but not developed from a cognitive perspective

Overview of NASA MSFC and UAH Space Weather Modeling and Data Efforts

NASA Technical Reports Server (NTRS)

Parker, Linda Neergaard

2016-01-01

Marshall Space Flight Center, along with its industry and academia neighbors, has a long history of space environment model development and testing. Space weather efforts include research, testing, model development, environment definition, anomaly investigation, and operational support. This presentation will highlight a few of the current space weather activities being performed at Marshall and through collaborative efforts with University of Alabama in Huntsville scientists.

Use of the Maximum Likelihood Method in the Analysis of Chamber Air Dives

DTIC Science & Technology

1988-01-01

the total gas pressure in compartment i, P0 is the current ambient pressure, 0 [ and A and B are constants (0.0026 min-’ -ATA- and 8.31 ATA...computer model (4), the Kidd- Stubbs 1971 decompression tables (11), and the current Defence and Civil Institute 20 of Environmental Medicine (DCIEM...it could be applied. Since the models are not suitable for this test, then within T ese no-deco current limits of statistical theory, the results can

Effects of tillage and application rate on atrazine transport to subsurface drainage: Evaluation of RZWQM using a six-year field study

USDA-ARS?s Scientific Manuscript database

Well-tested agricultural system models can improve our understanding of the water quality effects of management practices under different conditions. The Root Zone Water Quality Model (RZWQM) has been tested under a variety of conditions. However, the current model’s ability to simulate pesticide tr...

40 CFR 86.1905 - How does this program work?

Code of Federal Regulations, 2011 CFR

2011-07-01

... least in part on the Phase 1 or Phase 2 testing outcomes described in § 86.1915. (2) The engine family... this section. We may select an engine family from the current model year or any previous model year... months longer to complete Phase 2 testing if there is a reasonable basis for needing more time. In very...

Tests of Convection Electric Field Models For The January 10, 1997, Geomagnetic Storm

NASA Astrophysics Data System (ADS)

Jordanova, V.; Boonsiriseth, A.; Thorne, R.; Dotan, Y.

The January 10-11, 1997, geomagnetic storm was caused by the passage at Earth of a magnetic cloud with a negative to positive Bz variation extending for 1 day. The ge- omagnetic indices had values of minimum Dst=-83 nT and maximum Kp=6 during the period of southward IMF within the cloud. We simulate ring current development during this storm using our kinetic drift-loss model and compare the results inferred from Volland-Stern type, Weimer, and AMIE convection electric field models. A pen- etration electric field is added to the AMIE model [Boonsiriseth et al., 2001] in order to improve the agreement with measurements from the electric field instrument on Po- lar spacecraft. The ionospheric electric potentials are mapped to the equatorial plane using the Tsyganenko 1996 magnetic field model and the resulting equatorial poten- tial models are coupled with our ring current model. While the temporal evolution of the large-scale features is similar in all three convection models, detailed comparison indicates that AMIE model shows highly variable small-scale features not present in the Volland-Stern or Weimer convection models. Results from our kinetic ring current model are compared with energetic particle data from the HYDRA, TIMAS, IPS, and CAMMICE instruments on Polar to test the applicability of the convection electric field models for this storm period.

Using Workflow Modeling to Identify Areas to Improve Genetic Test Processes in the University of Maryland Translational Pharmacogenomics Project.

PubMed

Cutting, Elizabeth M; Overby, Casey L; Banchero, Meghan; Pollin, Toni; Kelemen, Mark; Shuldiner, Alan R; Beitelshees, Amber L

Delivering genetic test results to clinicians is a complex process. It involves many actors and multiple steps, requiring all of these to work together in order to create an optimal course of treatment for the patient. We used information gained from focus groups in order to illustrate the current process of delivering genetic test results to clinicians. We propose a business process model and notation (BPMN) representation of this process for a Translational Pharmacogenomics Project being implemented at the University of Maryland Medical Center, so that personalized medicine program implementers can identify areas to improve genetic testing processes. We found that the current process could be improved to reduce input errors, better inform and notify clinicians about the implications of certain genetic tests, and make results more easily understood. We demonstrate our use of BPMN to improve this important clinical process for CYP2C19 genetic testing in patients undergoing invasive treatment of coronary heart disease.

Using Workflow Modeling to Identify Areas to Improve Genetic Test Processes in the University of Maryland Translational Pharmacogenomics Project

PubMed Central

Cutting, Elizabeth M.; Overby, Casey L.; Banchero, Meghan; Pollin, Toni; Kelemen, Mark; Shuldiner, Alan R.; Beitelshees, Amber L.

2015-01-01

Delivering genetic test results to clinicians is a complex process. It involves many actors and multiple steps, requiring all of these to work together in order to create an optimal course of treatment for the patient. We used information gained from focus groups in order to illustrate the current process of delivering genetic test results to clinicians. We propose a business process model and notation (BPMN) representation of this process for a Translational Pharmacogenomics Project being implemented at the University of Maryland Medical Center, so that personalized medicine program implementers can identify areas to improve genetic testing processes. We found that the current process could be improved to reduce input errors, better inform and notify clinicians about the implications of certain genetic tests, and make results more easily understood. We demonstrate our use of BPMN to improve this important clinical process for CYP2C19 genetic testing in patients undergoing invasive treatment of coronary heart disease. PMID:26958179

Gummel Symmetry Test on charge based drain current expression using modified first-order hyperbolic velocity-field expression

NASA Astrophysics Data System (ADS)

Singh, Kirmender; Bhattacharyya, A. B.

2017-03-01

Gummel Symmetry Test (GST) has been a benchmark industry standard for MOSFET models and is considered as one of important tests by the modeling community. BSIM4 MOSFET model fails to pass GST as the drain current equation is not symmetrical because drain and source potentials are not referenced to bulk. BSIM6 MOSFET model overcomes this limitation by taking all terminal biases with reference to bulk and using proper velocity saturation (v -E) model. The drain current equation in BSIM6 is charge based and continuous in all regions of operation. It, however, adopts a complicated method to compute source and drain charges. In this work we propose to use conventional charge based method formulated by Enz for obtaining simpler analytical drain current expression that passes GST. For this purpose we adopt two steps: (i) In the first step we use a modified first-order hyperbolic v -E model with adjustable coefficients which is integrable, simple and accurate, and (ii) In the second we use a multiplying factor in the modified first-order hyperbolic v -E expression to obtain correct monotonic asymptotic behavior around the origin of lateral electric field. This factor is of empirical form, which is a function of drain voltage (vd) and source voltage (vs) . After considering both the above steps we obtain drain current expression whose accuracy is similar to that obtained from second-order hyperbolic v -E model. In modified first-order hyperbolic v -E expression if vd and vs is replaced by smoothing functions for the effective drain voltage (vdeff) and effective source voltage (vseff), it will as well take care of discontinuity between linear to saturation regions of operation. The condition of symmetry is shown to be satisfied by drain current and its higher order derivatives, as both of them are odd functions and their even order derivatives smoothly pass through the origin. In strong inversion region and technology node of 22 nm the GST is shown to pass till sixth-order derivative and for weak inversion it is shown till fifth-order derivative. In the expression of drain current major short channel phenomena like vertical field mobility reduction, velocity saturation and velocity overshoot have been taken into consideration.

Accelerated Testing and Modeling of Potential-Induced Degradation as a Function of Temperature and Relative Humidity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hacke, Peter; Spataru, Sergiu; Terwilliger, Kent

2015-06-14

An acceleration model based on the Peck equation was applied to power performance of crystalline silicon cell modules as a function of time and of temperature and humidity, the two main environmental stress factors that promote potential-induced degradation. This model was derived from module power degradation data obtained semi-continuously and statistically by in-situ dark current-voltage measurements in an environmental chamber. The modeling enables prediction of degradation rates and times as functions of temperature and humidity. Power degradation could be modeled linearly as a function of time to the second power; additionally, we found that coulombs transferred from the active cellmore » circuit to ground during the stress test is approximately linear with time. Therefore, the power loss could be linearized as a function of coulombs squared. With this result, we observed that when the module face was completely grounded with a condensed phase conductor, leakage current exceeded the anticipated corresponding degradation rate relative to the other tests performed in damp heat.« less

Highlights from High Energy Neutrino Experiments at CERN

NASA Astrophysics Data System (ADS)

Schlatter, W.-D.

2015-07-01

Experiments with high energy neutrino beams at CERN provided early quantitative tests of the Standard Model. This article describes results from studies of the nucleon quark structure and of the weak current, together with the precise measurement of the weak mixing angle. These results have established a new quality for tests of the electroweak model. In addition, the measurements of the nucleon structure functions in deep inelastic neutrino scattering allowed first quantitative tests of QCD.

Structural dynamic testing of composite propfan blades for a cruise missile wind tunnel model

NASA Technical Reports Server (NTRS)

Elgin, Stephen D.; Sutliff, Thomas J.

1993-01-01

The Naval Weapons Center at China Lake, California is currently evaluating a counter rotating propfan system as a means of propulsion for the next generation of cruise missiles. The details and results of a structural dynamic test program are presented for scale model graphite-epoxy composite propfan blades. These blades are intended for use on a cruise missile wind tunnel model. Both dynamic characteristics and strain operating limits of the blades are presented. Complications associated with high strain level fatigue testing methods are also discussed.

Finite element modelling of crash response of composite aerospace sub-floor structures

NASA Astrophysics Data System (ADS)

McCarthy, M. A.; Harte, C. G.; Wiggenraad, J. F. M.; Michielsen, A. L. P. J.; Kohlgrüber, D.; Kamoulakos, A.

Composite energy-absorbing structures for use in aircraft are being studied within a European Commission research programme (CRASURV - Design for Crash Survivability). One of the aims of the project is to evaluate the current capabilities of crashworthiness simulation codes for composites modelling. This paper focuses on the computational analysis using explicit finite element analysis, of a number of quasi-static and dynamic tests carried out within the programme. It describes the design of the structures, the analysis techniques used, and the results of the analyses in comparison to the experimental test results. It has been found that current multi-ply shell models are capable of modelling the main energy-absorbing processes at work in such structures. However some deficiencies exist, particularly in modelling fabric composites. Developments within the finite element code are taking place as a result of this work which will enable better representation of composite fabrics.

The construction of airfoil pressure models by the plate method: Achievements, current research, technology development and potential applications

NASA Technical Reports Server (NTRS)

Lawing, P. L.

1985-01-01

A method of constructing airfoils by inscribing pressure channels on the face of opposing plates, bonding them together to form one plate with integral channels, and contour machining this plate to form an airfoil model is described. The research and development program to develop the bonding technology is described as well as the construction and testing of an airfoil model. Sample aerodynamic data sets are presented and discussed. Also, work currently under way to produce thin airfoils with camber is presented. Samples of the aft section of a 6 percent airfoil with complete pressure instrumentation including the trailing edge are pictured and described. This technique is particularly useful in fabricating models for transonic cryogenic testing, but it should find application in a wide ange of model construction projects, as well as the fabrication of fuel injectors, space hardware, and other applications requiring advanced bonding technology and intricate fluid passages.

Application Study of a High Temperature Superconducting Fault Current Limiter for Electric Power System

NASA Astrophysics Data System (ADS)

Naito, Yuji; Shimizu, Iwao; Yamaguchi, Iwao; Kaiho, Katsuyuki; Yanabu, Satoru

Using high temperature superconductor, a Superconducting Fault Current Limiter (SFCL) was made and tested. Superconductor and vacuum interrupter as commutation switch are connected in parallel with bypass coil. When a fault occurs and the excessive current flows, superconductor is first quenched and the current is transferred to bypass coil because on voltage drop of superconductor. At the same time, since magnetic field is generated by current which flows in bypass coil, commutation switch is immediately driven by electromagnetic repulsion plate connected to driving rod of vacuum interrupter, and superconductor is separated from this circuit. Using the testing model, we could separate the superconductor from a circuit due to movement of vacuum interrupter within half-cycle current and transfer all current to bypass coil. Since operation of a commutation switch is included in current limiting operation of this testing model, it is one of helpful circuit of development of SFCL in the future. Moreover, since it can make the consumed energy of superconductor small during fault state due to realization of high-speed switch with simple composition, the burden of superconductor is reduced compared with conventional resistive type SFCL and it is considered that the flexibility of a SFCL design increases. Cooperation with a circuit breaker was also considered, the trial calculation of a parameter and energy of operation is conducted and discussion in the case of installing the SFCL to electric power system is made.

Mechanisms Affecting Performance of the BaBar Resistive Plate Chambers and Searches for Remediation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Changguo

2003-09-19

The BaBar experiment at PEPII relies on the Instrumentation of the Flux Return (IFR) for both muon identification and KL detection. The active detector is composed of Resistive Plate Chambers (RPC's) operated in streamer mode. Since the start of operation the RPC's have suffered persistent efficiency deterioration and dark current increase problems. The ''autopsy'' of bad BaBar RPC's revealed that in many cases uncured Linseed oil droplets had formed on the inner surface of the Bakelite plates, leading to current paths from oil ''stalagmites'' bridging the 2 mm gap. In this paper a possible model of this ''stalagmite'' formation andmore » its effect on the dark current and efficiency of RPC chambers is presented. Laboratory test results strongly support this model. Based upon this model we are searching for solutions to eliminate the unfavorable effect of the oil stalagmites. The lab tests show that the stalagmite resistivity increases dramatically if exposed to the air, an observation that points to a possible way to remedy the damage and increase the efficiency. We have seen that flowing an oxygen gas mixture into the chamber helps to polymerize the uncured linseed oil. Consequently the resistivity of the bridged oil stalagmites increases, as does that of the oil coating on the frame edges and spacers, significantly reducing the RPC dark currents and low-efficiency regions. We have tested this idea on two chambers removed from BaBar because of their low efficiency and high dark current. These test results are reported in the paper, and two other remediation methods also mentioned. We continue to study this problem, and try to find new treatments with permanent improvement.« less

Modelling of sediment transport and morphological evolution under the combined action of waves and currents

NASA Astrophysics Data System (ADS)

Franz, Guilherme; Delpey, Matthias T.; Brito, David; Pinto, Lígia; Leitão, Paulo; Neves, Ramiro

2017-09-01

Coastal defence structures are often constructed to prevent beach erosion. However, poorly designed structures may cause serious erosion problems in the downdrift direction. Morphological models are useful tools to predict such impacts and assess the efficiency of defence structures for different scenarios. Nevertheless, morphological modelling is still a topic under intense research effort. The processes simulated by a morphological model depend on model complexity. For instance, undertow currents are neglected in coastal area models (2DH), which is a limitation for simulating the evolution of beach profiles for long periods. Model limitations are generally overcome by predefining invariant equilibrium profiles that are allowed to shift offshore or onshore. A more flexible approach is described in this paper, which can be generalised to 3-D models. The present work is based on the coupling of the MOHID modelling system and the SWAN wave model. The impacts of different designs of detached breakwaters and groynes were simulated in a schematic beach configuration following a 2DH approach. The results of bathymetry evolution are in agreement with the patterns found in the literature for several existing structures. The model was also tested in a 3-D test case to simulate the formation of sandbars by undertow currents. The findings of this work confirmed the applicability of the MOHID modelling system to study sediment transport and morphological changes in coastal zones under the combined action of waves and currents. The same modelling methodology was applied to a coastal zone (Costa da Caparica) located at the mouth of a mesotidal estuary (Tagus Estuary, Portugal) to evaluate the hydrodynamics and sediment transport both in calm water conditions and during events of highly energetic waves. The MOHID code is available in the GitHub repository.

Estimation of stress distribution in ferromagnetic tensile specimens using low cost eddy current stress measurement system and BP neural network.

PubMed

Li, Jianwei; Zhang, Weimin; Zeng, Weiqin; Chen, Guolong; Qiu, Zhongchao; Cao, Xinyuan; Gao, Xuanyi

2017-01-01

Estimation of the stress distribution in ferromagnetic components is very important for evaluating the working status of mechanical equipment and implementing preventive maintenance. Eddy current testing technology is a promising method in this field because of its advantages of safety, no need of coupling agent, etc. In order to reduce the cost of eddy current stress measurement system, and obtain the stress distribution in ferromagnetic materials without scanning, a low cost eddy current stress measurement system based on Archimedes spiral planar coil was established, and a method based on BP neural network to obtain the stress distribution using the stress of several discrete test points was proposed. To verify the performance of the developed test system and the validity of the proposed method, experiment was implemented using structural steel (Q235) specimens. Standard curves of sensors at each test point were achieved, the calibrated data were used to establish the BP neural network model for approximating the stress variation on the specimen surface, and the stress distribution curve of the specimen was obtained by interpolating with the established model. The results show that there is a good linear relationship between the change of signal modulus and the stress in most elastic range of the specimen, and the established system can detect the change in stress with a theoretical average sensitivity of -0.4228 mV/MPa. The obtained stress distribution curve is well consonant with the theoretical analysis result. At last, possible causes and improving methods of problems appeared in the results were discussed. This research has important significance for reducing the cost of eddy current stress measurement system, and advancing the engineering application of eddy current stress testing.

Estimation of stress distribution in ferromagnetic tensile specimens using low cost eddy current stress measurement system and BP neural network

PubMed Central

Li, Jianwei; Zeng, Weiqin; Chen, Guolong; Qiu, Zhongchao; Cao, Xinyuan; Gao, Xuanyi

2017-01-01

Estimation of the stress distribution in ferromagnetic components is very important for evaluating the working status of mechanical equipment and implementing preventive maintenance. Eddy current testing technology is a promising method in this field because of its advantages of safety, no need of coupling agent, etc. In order to reduce the cost of eddy current stress measurement system, and obtain the stress distribution in ferromagnetic materials without scanning, a low cost eddy current stress measurement system based on Archimedes spiral planar coil was established, and a method based on BP neural network to obtain the stress distribution using the stress of several discrete test points was proposed. To verify the performance of the developed test system and the validity of the proposed method, experiment was implemented using structural steel (Q235) specimens. Standard curves of sensors at each test point were achieved, the calibrated data were used to establish the BP neural network model for approximating the stress variation on the specimen surface, and the stress distribution curve of the specimen was obtained by interpolating with the established model. The results show that there is a good linear relationship between the change of signal modulus and the stress in most elastic range of the specimen, and the established system can detect the change in stress with a theoretical average sensitivity of -0.4228 mV/MPa. The obtained stress distribution curve is well consonant with the theoretical analysis result. At last, possible causes and improving methods of problems appeared in the results were discussed. This research has important significance for reducing the cost of eddy current stress measurement system, and advancing the engineering application of eddy current stress testing. PMID:29145500

Modeling and experimental validation of a Hybridized Energy Storage System for automotive applications

NASA Astrophysics Data System (ADS)

Fiorenti, Simone; Guanetti, Jacopo; Guezennec, Yann; Onori, Simona

2013-11-01

This paper presents the development and experimental validation of a dynamic model of a Hybridized Energy Storage System (HESS) consisting of a parallel connection of a lead acid (PbA) battery and double layer capacitors (DLCs), for automotive applications. The dynamic modeling of both the PbA battery and the DLC has been tackled via the equivalent electric circuit based approach. Experimental tests are designed for identification purposes. Parameters of the PbA battery model are identified as a function of state of charge and current direction, whereas parameters of the DLC model are identified for different temperatures. A physical HESS has been assembled at the Center for Automotive Research The Ohio State University and used as a test-bench to validate the model against a typical current profile generated for Start&Stop applications. The HESS model is then integrated into a vehicle simulator to assess the effects of the battery hybridization on the vehicle fuel economy and mitigation of the battery stress.

78 FR 45104 - Model Manufactured Home Installation Standards: Ground Anchor Installations

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-26

... test methods for establishing working load design values of ground anchor assemblies used for new... anchor installations and establish standardized test methods to determine ground anchor performance and... currently no national test method for rating and certifying ground anchor assemblies in different soil...

The Talent Search Model: Past, Present, and Future

ERIC Educational Resources Information Center

Swiatek, Mary Ann

2007-01-01

Typical standardized achievement tests cannot provide accurate information about gifted students' abilities because they are not challenging enough for such students. Talent searches solve this problem through above-level testing--using tests designed for older students to raise the ceiling for younger, gifted students. Currently, talent search…

Modeling Post-Accident Vehicle Egress

DTIC Science & Technology

2013-01-01

interest for military situations may involve rolled-over vehicles for which detailed movement data are not available. In the current design process...test trials. These evaluations are expensive and time-consuming, and are often performed late in the design process when it is too difficult to...alter the design if weaknesses are discovered. Yet, due to the limitations of current software tools, digital human models (DHMs) are not yet widely

Modeling and Simulation for a Surf Zone Robot

DTIC Science & Technology

2012-12-14

of-freedom surf zone robot is developed and tested with a physical test platform and with a simulated robot in Robot Operating System . Derived from...terrain. The application of the model to future platforms is analyzed and a broad examination of the current state of surf zone robotic systems is...public release; distribution is unlimited MODELING AND SIMULATION FOR A SURF ZONE ROBOT Eric Shuey Lieutenant, United States Navy B.S., Systems

Preliminary Upper Estimate of Peak Currents in Transcranial Magnetic Stimulation at Distant Locations from a TMS Coil

PubMed Central

Makarov, Sergey N.; Yanamadala, Janakinadh; Piazza, Matthew W.; Helderman, Alex M.; Thang, Niang S.; Burnham, Edward H.; Pascual-Leone, Alvaro

2016-01-01

Goals Transcranial magnetic stimulation (TMS) is increasingly used as a diagnostic and therapeutic tool for numerous neuropsychiatric disorders. The use of TMS might cause whole-body exposure to undesired induced currents in patients and TMS operators. The aim of the present study is to test and justify a simple analytical model known previously, which may be helpful as an upper estimate of eddy current density at a particular distant observation point for any body composition and any coil setup. Methods We compare the analytical solution with comprehensive adaptive mesh refinement-based FEM simulations of a detailed full-body human model, two coil types, five coil positions, about 100,000 observation points, and two distinct pulse rise times, thus providing a representative number of different data sets for comparison, while also using other numerical data. Results Our simulations reveal that, after a certain modification, the analytical model provides an upper estimate for the eddy current density at any location within the body. In particular, it overestimates the peak eddy currents at distant locations from a TMS coil by a factor of 10 on average. Conclusion The simple analytical model tested in the present study may be valuable as a rapid method to safely estimate levels of TMS currents at different locations within a human body. Significance At present, safe limits of general exposure to TMS electric and magnetic fields are an open subject, including fetal exposure for pregnant women. PMID:26685221

Reassessing the NTCTCS Staging Systems for Differentiated Thyroid Cancer, Including Age at Diagnosis

PubMed Central

McLeod, Donald S.A.; Jonklaas, Jacqueline; Brierley, James D.; Ain, Kenneth B.; Cooper, David S.; Fein, Henry G.; Haugen, Bryan R.; Ladenson, Paul W.; Magner, James; Ross, Douglas S.; Skarulis, Monica C.; Steward, David L.; Xing, Mingzhao; Litofsky, Danielle R.; Maxon, Harry R.

2015-01-01

Background: Thyroid cancer is unique for having age as a staging variable. Recently, the commonly used age cut-point of 45 years has been questioned. Objective: This study assessed alternate staging systems on the outcome of overall survival, and compared these with current National Thyroid Cancer Treatment Cooperative Study (NTCTCS) staging systems for papillary and follicular thyroid cancer. Methods: A total of 4721 patients with differentiated thyroid cancer were assessed. Five potential alternate staging systems were generated at age cut-points in five-year increments from 35 to 70 years, and tested for model discrimination (Harrell's C-statistic) and calibration (R2). The best five models for papillary and follicular cancer were further tested with bootstrap resampling and significance testing for discrimination. Results: The best five alternate papillary cancer systems had age cut-points of 45–50 years, with the highest scoring model using 50 years. No significant difference in C-statistic was found between the best alternate and current NTCTCS systems (p = 0.200). The best five alternate follicular cancer systems had age cut-points of 50–55 years, with the highest scoring model using 50 years. All five best alternate staging systems performed better compared with the current system (p = 0.003–0.035). There was no significant difference in discrimination between the best alternate system (cut-point age 50 years) and the best system of cut-point age 45 years (p = 0.197). Conclusions: No alternate papillary cancer systems assessed were significantly better than the current system. New alternate staging systems for follicular cancer appear to be better than the current NTCTCS system, although they require external validation. PMID:26203804

Prediction of Acoustic Loads Generated by Propulsion Systems

NASA Technical Reports Server (NTRS)

Perez, Linamaria; Allgood, Daniel C.

2011-01-01

NASA Stennis Space Center is one of the nation's premier facilities for conducting large-scale rocket engine testing. As liquid rocket engines vary in size, so do the acoustic loads that they produce. When these acoustic loads reach very high levels they may cause damages both to humans and to actual structures surrounding the testing area. To prevent these damages, prediction tools are used to estimate the spectral content and levels of the acoustics being generated by the rocket engine plumes and model their propagation through the surrounding atmosphere. Prior to the current work, two different acoustic prediction tools were being implemented at Stennis Space Center, each having their own advantages and disadvantages depending on the application. Therefore, a new prediction tool was created, using NASA SP-8072 handbook as a guide, which would replicate the same prediction methods as the previous codes, but eliminate any of the drawbacks the individual codes had. Aside from replicating the previous modeling capability in a single framework, additional modeling functions were added thereby expanding the current modeling capability. To verify that the new code could reproduce the same predictions as the previous codes, two verification test cases were defined. These verification test cases also served as validation cases as the predicted results were compared to actual test data.

Estimating Pesticide Effects on Fecundity Rates of Wild Birds Using Current Laboratory Reproduction Tests

EPA Science Inventory

The manuscript reviews the issues concerning the use of results on pesticide effects from laboratory avian reproduction tests for estimating potential impacts of pesticides on fecundity rates in avian population models.

The Storm Time Ring Current Dynamics and Response to CMEs and CIRs Using Van Allen Probes Observations and CIMI Simulations

NASA Astrophysics Data System (ADS)

Bingham, S.; Mouikis, C.; Kistler, L. M.; Fok, M. C. H.; Glocer, A.; Farrugia, C. J.; Gkioulidou, M.; Spence, H. E.

2016-12-01

The ring current responds differently to the different solar and interplanetary storm drivers such as coronal mass injections, (CMEs), and co-rotating interaction regions (CIRs). Delineating the differences in the ring current development between these two drivers will aid our understanding of the ring current dynamics. Using Van Allen Probes observations, we develop an empirical ring current model of the ring current pressure, the pressure anisotropy and the current density development during the storm phases for both types of storm drivers and for all MLTs inside L 6. In addition, we identify the populations (energy and species) responsible. We find that during the storm main phase and the early recovery phase the plasma sheet particles (10-80 keV) convecting from the nightside contribute the most on the ring current pressure and current density. However, during these phases, the main difference between CMEs and CIRs is in the O+ contribution. This empirical model is compared to the results of CIMI simulations of CMEs and CIRs where the model input is comprised of the superposed epoch solar wind conditions of the storms that comprise the empirical model, while different inner magnetosphere boundary conditions will be tested in order to match the empirical model results. Comparing the model and simulation results will fill our understanding of the ring current dynamics as part of the highly coupled inner magnetosphere system.

Experimental testing of scattering polarization models

NASA Astrophysics Data System (ADS)

Li, Wenxian; Casini, Roberto; Tomczyk, Steven; Landi Degl'Innocenti, Egidio; Marsell, Brandan

2018-06-01

We realized a laboratory experiment to study the polarization of the Na I doublet at 589.3 nm, in the presence of a magnetic field. The purpose of the experiment is to test the theory of scattering polarization for illumination conditions typical of astrophysical plasmas. This work was stimulated by solar observations of the Na I doublet that have proven particularly challenging to reproduce with current models of polarized line formation, even casting doubts on our very understanding of the physics of scattering polarization on the Sun. The experiment has confirmed the fundamental correctness of the current theory, and demonstrated that the "enigmatic'' polarization of those observations is exclusively of solar origin.

Systems engineering approach to environmental risk management: A case study of depleted uranium at test area C-64, Eglin Air Force Base, Florida. Master`s thesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carter, C.M.; Fortmann, K.M.; Hill, S.W.

1994-12-01

Environmental restoration is an area of concern in an environmentally conscious world. Much effort is required to clean up the environment and promote environmentally sound methods for managing current land use. In light of the public consciousness with the latter topic, the United States Air Force must also take an active role in addressing these environmental issues with respect to current and future USAF base land use. This thesis uses the systems engineering technique to assess human health risks and to evaluate risk management options with respect to depleted uranium contamination in the sampled region of Test Area (TA) C-64more » at Eglin Air Force Base (AFB). The research combines the disciplines of environmental data collection, DU soil concentration distribution modeling, ground water modeling, particle resuspension modeling, exposure assessment, health hazard assessment, and uncertainty analysis to characterize the test area. These disciplines are required to quantify current and future health risks, as well as to recommend cost effective ways to increase confidence in health risk assessment and remediation options.« less

Payload Planning for the International Space Station

NASA Technical Reports Server (NTRS)

Johnson, Tameka J.

1995-01-01

A review of the evolution of the International Space Station (ISS) was performed for the purpose of understanding the project objectives. It was requested than an analysis of the current Office of Space Access and Technology (OSAT) Partnership Utilization Plan (PUP) traffic model be completed to monitor the process through which the scientific experiments called payloads are manifested for flight to the ISS. A viewing analysis of the ISS was also proposed to identify the capability to observe the United States Laboratory (US LAB) during the assembly sequence. Observations of the Drop-Tower experiment and nondestructive testing procedures were also performed to maximize the intern's technical experience. Contributions were made to the meeting in which the 1996 OSAT or Code X PUP traffic model was generated using the software tool, Filemaker Pro. The current OSAT traffic model satisfies the requirement for manifesting and delivering the proposed payloads to station. The current viewing capability of station provides the ability to view the US LAB during station assembly sequence. The Drop Tower experiment successfully simulates the effect of microgravity and conveniently documents the results for later use. The non-destructive test proved effective in determining stress in various components tested.

Structural Equation Modeling in Language Testing and Learning Research: A Review

ERIC Educational Resources Information Center

In'nami, Yo; Koizumi, Rie

2011-01-01

Despite the recent increase of structural equation modeling (SEM) in language testing and learning research and Kunnan's (1998) call for the proper use of SEM to produce useful findings, there seem to be no reviews about how SEM is applied in these areas or about the extent to which the current application accords with appropriate practices. To…

The two-way relationship between ionospheric outflow and the ring current

DOE Office of Scientific and Technical Information (OSTI.GOV)

Welling, Daniel T.; Jordanova, Vania Koleva; Glocer, Alex

It is now well established that the ionosphere, because it acts as a significant source of plasma, plays a critical role in ring current dynamics. However, because the ring current deposits energy into the ionosphere, the inverse may also be true: the ring current can play a critical role in the dynamics of ionospheric outflow. This study uses a set of coupled, first-principles-based numerical models to test the dependence of ionospheric outflow on ring current-driven region 2 field-aligned currents (FACs). A moderate magnetospheric storm event is modeled with the Space Weather Modeling Framework using a global MHD code (Block Adaptivemore » Tree Solar wind Roe-type Upwind Scheme, BATS-R-US), a polar wind model (Polar Wind Outflow Model), and a bounce-averaged kinetic ring current model (ring current atmosphere interaction model with self-consistent magnetic field, RAM-SCB). Initially, each code is two-way coupled to all others except for RAM-SCB, which receives inputs from the other models but is not allowed to feed back pressure into the MHD model. The simulation is repeated with pressure coupling activated, which drives strong pressure gradients and region 2 FACs in BATS-R-US. It is found that the region 2 FACs increase heavy ion outflow by up to 6 times over the non-coupled results. The additional outflow further energizes the ring current, establishing an ionosphere-magnetosphere mass feedback loop. This study further demonstrates that ionospheric outflow is not merely a plasma source for the magnetosphere but an integral part in the nonlinear ionosphere-magnetosphere-ring current system.« less

The two-way relationship between ionospheric outflow and the ring current

DOE PAGES

Welling, Daniel T.; Jordanova, Vania Koleva; Glocer, Alex; ...

2015-06-01

It is now well established that the ionosphere, because it acts as a significant source of plasma, plays a critical role in ring current dynamics. However, because the ring current deposits energy into the ionosphere, the inverse may also be true: the ring current can play a critical role in the dynamics of ionospheric outflow. This study uses a set of coupled, first-principles-based numerical models to test the dependence of ionospheric outflow on ring current-driven region 2 field-aligned currents (FACs). A moderate magnetospheric storm event is modeled with the Space Weather Modeling Framework using a global MHD code (Block Adaptivemore » Tree Solar wind Roe-type Upwind Scheme, BATS-R-US), a polar wind model (Polar Wind Outflow Model), and a bounce-averaged kinetic ring current model (ring current atmosphere interaction model with self-consistent magnetic field, RAM-SCB). Initially, each code is two-way coupled to all others except for RAM-SCB, which receives inputs from the other models but is not allowed to feed back pressure into the MHD model. The simulation is repeated with pressure coupling activated, which drives strong pressure gradients and region 2 FACs in BATS-R-US. It is found that the region 2 FACs increase heavy ion outflow by up to 6 times over the non-coupled results. The additional outflow further energizes the ring current, establishing an ionosphere-magnetosphere mass feedback loop. This study further demonstrates that ionospheric outflow is not merely a plasma source for the magnetosphere but an integral part in the nonlinear ionosphere-magnetosphere-ring current system.« less

Past, Present, and Future Capabilities of the Transonic Dynamics Tunnel from an Aeroelasticity Perspective

NASA Technical Reports Server (NTRS)

Cole, Stanley R.; Garcia, Jerry L.

2000-01-01

The NASA Langley Transonic Dynamics Tunnel (TDT) has provided a unique capability for aeroelastic testing for forty years. The facility has a rich history of significant contributions to the design of many United States commercial transports, military aircraft, launch vehicles, and spacecraft. The facility has many features that contribute to its uniqueness for aeroelasticity testing, perhaps the most important feature being the use of a heavy gas test medium to achieve higher test densities. Higher test medium densities substantially improve model-building requirements and therefore simplify the fabrication process for building aeroelastically scaled wind tunnel models. Aeroelastic scaling for the heavy gas results in lower model structural frequencies. Lower model frequencies tend to a make aeroelastic testing safer. This paper will describe major developments in the testing capabilities at the TDT throughout its history, the current status of the facility, and planned additions and improvements to its capabilities in the near future.

Learning Classification Models of Cognitive Conditions from Subtle Behaviors in the Digital Clock Drawing Test

PubMed Central

Souillard-Mandar, William; Davis, Randall; Rudin, Cynthia; Au, Rhoda; Libon, David J.; Swenson, Rodney; Price, Catherine C.; Lamar, Melissa; Penney, Dana L.

2015-01-01

The Clock Drawing Test – a simple pencil and paper test – has been used for more than 50 years as a screening tool to differentiate normal individuals from those with cognitive impairment, and has proven useful in helping to diagnose cognitive dysfunction associated with neurological disorders such as Alzheimer’s disease, Parkinson’s disease, and other dementias and conditions. We have been administering the test using a digitizing ballpoint pen that reports its position with considerable spatial and temporal precision, making available far more detailed data about the subject’s performance. Using pen stroke data from these drawings categorized by our software, we designed and computed a large collection of features, then explored the tradeoffs in performance and interpretability in classifiers built using a number of different subsets of these features and a variety of different machine learning techniques. We used traditional machine learning methods to build prediction models that achieve high accuracy. We operationalized widely used manual scoring systems so that we could use them as benchmarks for our models. We worked with clinicians to define guidelines for model interpretability, and constructed sparse linear models and rule lists designed to be as easy to use as scoring systems currently used by clinicians, but more accurate. While our models will require additional testing for validation, they offer the possibility of substantial improvement in detecting cognitive impairment earlier than currently possible, a development with considerable potential impact in practice. PMID:27057085

Learning Classification Models of Cognitive Conditions from Subtle Behaviors in the Digital Clock Drawing Test.

PubMed

Souillard-Mandar, William; Davis, Randall; Rudin, Cynthia; Au, Rhoda; Libon, David J; Swenson, Rodney; Price, Catherine C; Lamar, Melissa; Penney, Dana L

2016-03-01

The Clock Drawing Test - a simple pencil and paper test - has been used for more than 50 years as a screening tool to differentiate normal individuals from those with cognitive impairment, and has proven useful in helping to diagnose cognitive dysfunction associated with neurological disorders such as Alzheimer's disease, Parkinson's disease, and other dementias and conditions. We have been administering the test using a digitizing ballpoint pen that reports its position with considerable spatial and temporal precision, making available far more detailed data about the subject's performance. Using pen stroke data from these drawings categorized by our software, we designed and computed a large collection of features, then explored the tradeoffs in performance and interpretability in classifiers built using a number of different subsets of these features and a variety of different machine learning techniques. We used traditional machine learning methods to build prediction models that achieve high accuracy. We operationalized widely used manual scoring systems so that we could use them as benchmarks for our models. We worked with clinicians to define guidelines for model interpretability, and constructed sparse linear models and rule lists designed to be as easy to use as scoring systems currently used by clinicians, but more accurate. While our models will require additional testing for validation, they offer the possibility of substantial improvement in detecting cognitive impairment earlier than currently possible, a development with considerable potential impact in practice.

Model Scaling of Hydrokinetic Ocean Renewable Energy Systems

NASA Astrophysics Data System (ADS)

von Ellenrieder, Karl; Valentine, William

2013-11-01

Numerical simulations are performed to validate a non-dimensional dynamic scaling procedure that can be applied to subsurface and deeply moored systems, such as hydrokinetic ocean renewable energy devices. The prototype systems are moored in water 400 m deep and include: subsurface spherical buoys moored in a shear current and excited by waves; an ocean current turbine excited by waves; and a deeply submerged spherical buoy in a shear current excited by strong current fluctuations. The corresponding model systems, which are scaled based on relative water depths of 10 m and 40 m, are also studied. For each case examined, the response of the model system closely matches the scaled response of the corresponding full-sized prototype system. The results suggest that laboratory-scale testing of complete ocean current renewable energy systems moored in a current is possible. This work was supported by the U.S. Southeast National Marine Renewable Energy Center (SNMREC).

Echoes of a Forgotten Past: Eugenics, Testing, and Education Reform.

ERIC Educational Resources Information Center

Stoskopf, Alan

2002-01-01

Review of the work of Goddard, Terman, and Thorndike and the role of eugenics and the intelligence quotient in testing points out dangers to be avoided in the current testing climate, such as use of the business model, single-number scores, and tracking. (Contains 42 references.) (SK)

Detection of CMOS bridging faults using minimal stuck-at fault test sets

NASA Technical Reports Server (NTRS)

Ijaz, Nabeel; Frenzel, James F.

1993-01-01

The performance of minimal stuck-at fault test sets at detecting bridging faults are evaluated. New functional models of circuit primitives are presented which allow accurate representation of bridging faults under switch-level simulation. The effectiveness of the patterns is evaluated using both voltage and current testing.

Simulation of Wave-Current Interaction Using a Three-Dimensional Hydrodynamic Model Coupled With a Phase Averaged Wave Model

NASA Astrophysics Data System (ADS)

Marsooli, R.; Orton, P. M.; Georgas, N.; Blumberg, A. F.

2016-02-01

The Stevens Institute of Technology Estuarine and Coastal Ocean Model (sECOM) has been coupled with a more advanced surface wave model to simulate wave‒current interaction, and results have been validated in estuarine and nearshore waters. sECOM is a three‒dimensional, hydrostatic, free surface, primitive equation model. It solves the Navier‒Stokes equations and the conservation equations for temperature and salinity using a finite‒difference method on an Arakawa C‒grid with a terrain‒following (sigma) vertical coordinate and orthogonal curvilinear horizontal coordinate system. The model is coupled with the surface wave model developed by Mellor et al. (2008), which solves the spectral equation and takes into account depth and current refraction, and deep and shallow water. The wave model parameterizes the energy distribution in frequency space and the wave‒wave interaction process by using a specified spectrum shape. The coupled wave‒hydrodynamic model considers the wave‒current interaction through wave‒induced bottom stress, depth‒dependent radiation stress, and wave effects on wind‒induced surface stress. The model is validated using the data collected at a natural sandy beach at Duck, North Carolina, during the DUCK94 experiment. This test case reveals the capability of the model to simulate the wave‒current interaction in nearshore coastal systems. The model is further validated using the data collected in Jamaica Bay, a semi‒enclosed body of water located in New York City region. This test reveals the applicability of the model to estuarine systems. These validations of the model and comparisons to its prior wave model, the Great Lakes Environmental Research Laboratory (GLERL) wave model (Donelan 1977), are presented and discussed. ReferencesG.L. Mellor, M.A. Donelan, and L‒Y. Oey, 2008, A Surface Wave Model for Coupling with Numerical Ocean Circulation Models. J. Atmos. Oceanic Technol., 25, 1785‒1807.Donelan, M. A 1977. A simple numerical model for wave and wind stress application. Report, National Water Research Institute, Burlington, Ontario, Canada, 28 pp.

Underground Test Area Subproject Phase I Data Analysis Task. Volume VIII - Risk Assessment Documentation Package

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

Volume VIII of the documentation for the Phase I Data Analysis Task performed in support of the current Regional Flow Model, Transport Model, and Risk Assessment for the Nevada Test Site Underground Test Area Subproject contains the risk assessment documentation. Because of the size and complexity of the model area, a considerable quantity of data was collected and analyzed in support of the modeling efforts. The data analysis task was consequently broken into eight subtasks, and descriptions of each subtask's activities are contained in one of the eight volumes that comprise the Phase I Data Analysis Documentation.

Scheduling viability tests for seeds in long-term storage based on a Bayesian Multi-Level Model

USDA-ARS?s Scientific Manuscript database

Genebank managers conduct viability tests on stored seeds so they can replace lots that have viability near a critical threshold, such as 50 or 85% germination. Currently, these tests are typically scheduled at uniform intervals; testing every 5 years is common. A manager needs to balance the cost...

Commentary: Student Cognition, the Situated Learning Context, and Test Score Interpretation

ERIC Educational Resources Information Center

La Marca, Paul M.

2006-01-01

Although it is assumed that student cognition contributes to student performance on achievement tests, it may be that current testing models lack the degree of specification necessary to warrant such inferences. With test score interpretations as the referent, the authors in this special issue address the role of student cognition in learning and…

Development of Electronic Load Controllers for Free-Piston Stirling Convertors Aided by Stirling Simulation Model

NASA Technical Reports Server (NTRS)

Regan, Timothy F.

2004-01-01

The free-piston Stirling convertor end-to-end modeling effort at the NASA Glenn Research Center has produced a software-based test bed in which free-piston Stirling convertors can be simulated and evaluated. The simulation model includes all the components of the convertor: the Stirling cycle engine, heat source, linear alternator, controller, and load. So far, it has been used in evaluating the performance of electronic controller designs. Three different controller design concepts were simulated using the model: 1) Controllers with parasitic direct current loading. 2) Controllers with parasitic alternating current loading. 3) Controllers that maintain a reference current. The free-piston Stirling convertor is an electromechanical device that operates at resonance. It is the function of the electronic load controller to ensure that the electrical load seen by the machine is always great enough to keep the amplitude of the piston and alternator oscillation at the rated value. This is done by regulating the load on the output bus. The controller monitors the instantaneous voltage, regulating it by switching loads called parasitic loads onto the bus whenever the bus voltage is too high and removing them whenever the voltage is too low. In the first type of controller, the monitor-ing and switching are done on the direct-current (dc) bus. In the second type, the alternating current bus is used. The model allows designers to test a controller concept before investing time in hardware. The simulation code used to develop the model also offers detailed models of digital and analog electronic components so that the resulting designs are realistic enough to translate directly into hardware circuits.

Weak annihilation and new physics in charmless [Formula: see text] decays.

PubMed

Bobeth, Christoph; Gorbahn, Martin; Vickers, Stefan

We use currently available data of nonleptonic charmless 2-body [Formula: see text] decays ([Formula: see text]) that are mediated by [Formula: see text] QCD- and QED-penguin operators to study weak annihilation and new-physics effects in the framework of QCD factorization. In particular we introduce one weak-annihilation parameter for decays related by [Formula: see text] quark interchange and test this universality assumption. Within the standard model, the data supports this assumption with the only exceptions in the [Formula: see text] system, which exhibits the well-known "[Formula: see text] puzzle", and some tensions in [Formula: see text]. Beyond the standard model, we simultaneously determine weak-annihilation and new-physics parameters from data, employing model-independent scenarios that address the "[Formula: see text] puzzle", such as QED-penguins and [Formula: see text] current-current operators. We discuss also possibilities that allow further tests of our assumption once improved measurements from LHCb and Belle II become available.

Practical Results from the Application of Model Checking and Test Generation from UML/SysML Models of On-Board Space Applications

NASA Astrophysics Data System (ADS)

Faria, J. M.; Mahomad, S.; Silva, N.

2009-05-01

The deployment of complex safety-critical applications requires rigorous techniques and powerful tools both for the development and V&V stages. Model-based technologies are increasingly being used to develop safety-critical software, and arguably, turning to them can bring significant benefits to such processes, however, along with new challenges. This paper presents the results of a research project where we tried to extend current V&V methodologies to be applied on UML/SysML models and aiming at answering the demands related to validation issues. Two quite different but complementary approaches were investigated: (i) model checking and the (ii) extraction of robustness test-cases from the same models. These two approaches don't overlap and when combined provide a wider reaching model/design validation ability than each one alone thus offering improved safety assurance. Results are very encouraging, even though they either fell short of the desired outcome as shown for model checking, or still appear as not fully matured as shown for robustness test case extraction. In the case of model checking, it was verified that the automatic model validation process can become fully operational and even expanded in scope once tool vendors help (inevitably) to improve the XMI standard interoperability situation. For the robustness test case extraction methodology, the early approach produced interesting results but need further systematisation and consolidation effort in order to produce results in a more predictable fashion and reduce reliance on expert's heuristics. Finally, further improvements and innovation research projects were immediately apparent for both investigated approaches, which point to either circumventing current limitations in XMI interoperability on one hand and bringing test case specification onto the same graphical level as the models themselves and then attempting to automate the generation of executable test cases from its standard UML notation.

Dual-Routine HCV/HIV Testing: Seroprevalence and Linkage to Care in Four Community Health Centers in Philadelphia, Pennsylvania.

PubMed

Coyle, Catelyn; Kwakwa, Helena

2016-01-01

Despite common risk factors, screening for hepatitis C virus (HCV) and HIV at the same time as part of routine medical care (dual-routine HCV/HIV testing) is not commonly implemented in the United States. This study examined improvements in feasibility of implementation, screening increase, and linkage to care when a dual-routine HCV/HIV testing model was integrated into routine primary care. National Nursing Centers Consortium implemented a dual-routine HCV/HIV testing model at four community health centers in Philadelphia, Pennsylvania, on September 1, 2013. Routine HCV and opt-out HIV testing replaced the routine HCV and opt-in HIV testing model through medical assistant-led, laboratory-based testing and electronic medical record modification to prompt, track, report, and facilitate reimbursement for tests performed on uninsured individuals. This study examined testing, seropositivity, and linkage-to-care comparison data for the nine months before (December 1, 2012-August 31, 2013) and after (September 1, 2013-May 31, 2014) implementation of the dual-routine HCV/HIV testing model. A total of 1,526 HCV and 1,731 HIV tests were performed before, and 1,888 HCV and 3,890 HIV tests were performed after dual-routine testing implementation, resulting in a 23.7% increase in HCV tests and a 124.7% increase in HIV tests. A total of 70 currently HCV-infected and four new HIV-seropositive patients vs. 101 HCV-infected and 13 new HIV-seropositive patients were identified during these two periods, representing increases of 44.3% for HCV antibody-positive and RNA-positive tests and 225.0% for HIV-positive tests. Linkage to care increased from 27 currently infected HCV--positive and one HIV-positive patient pre-dual-routine testing to 39 HCV--positive and nine HIV-positive patients post-dual-routine testing. The dual-routine HCV/HIV testing model shows that integrating dual-routine testing in a primary care setting is possible and leads to increased HCV and HIV screening, enhanced seropositivity diagnosis, and improved linkage to care.

Dual-Routine HCV/HIV Testing: Seroprevalence and Linkage to Care in Four Community Health Centers in Philadelphia, Pennsylvania

PubMed Central

Kwakwa, Helena

2016-01-01

Objective Despite common risk factors, screening for hepatitis C virus (HCV) and HIV at the same time as part of routine medical care (dual-routine HCV/HIV testing) is not commonly implemented in the United States. This study examined improvements in feasibility of implementation, screening increase, and linkage to care when a dual-routine HCV/HIV testing model was integrated into routine primary care. Methods National Nursing Centers Consortium implemented a dual-routine HCV/HIV testing model at four community health centers in Philadelphia, Pennsylvania, on September 1, 2013. Routine HCV and opt-out HIV testing replaced the routine HCV and opt-in HIV testing model through medical assistant-led, laboratory-based testing and electronic medical record modification to prompt, track, report, and facilitate reimbursement for tests performed on uninsured individuals. This study examined testing, seropositivity, and linkage-to-care comparison data for the nine months before (December 1, 2012–August 31, 2013) and after (September 1, 2013–May 31, 2014) implementation of the dual-routine HCV/HIV testing model. Results A total of 1,526 HCV and 1,731 HIV tests were performed before, and 1,888 HCV and 3,890 HIV tests were performed after dual-routine testing implementation, resulting in a 23.7% increase in HCV tests and a 124.7% increase in HIV tests. A total of 70 currently HCV-infected and four new HIV-seropositive patients vs. 101 HCV-infected and 13 new HIV-seropositive patients were identified during these two periods, representing increases of 44.3% for HCV antibody-positive and RNA-positive tests and 225.0% for HIV-positive tests. Linkage to care increased from 27 currently infected HCV--positive and one HIV-positive patient pre-dual-routine testing to 39 HCV--positive and nine HIV-positive patients post-dual-routine testing. Conclusion The dual-routine HCV/HIV testing model shows that integrating dual-routine testing in a primary care setting is possible and leads to increased HCV and HIV screening, enhanced seropositivity diagnosis, and improved linkage to care. PMID:26862229

Network simulation modeling of equine infectious anemia in the non-racehorse population in Japan.

PubMed

Hayama, Yoko; Kobayashi, Sota; Nishida, Takeshi; Muroga, Norihiko; Tsutsui, Toshiyuki

2012-01-01

An equine infectious anemia (EIA) transmission model was developed by constructing a network structure of horse movement patterns in a non-racehorse population. This model was then used to evaluate the effectiveness and efficiency of several EIA surveillance strategies. Because EIA had not been detected in Japan since 1993, it was appropriate to review the current surveillance strategy, which aims to eradicate EIA by intensive testing, and to consider alternative strategies suitable for the current EIA status in Japan. The non-racehorse population was divided into four sectors based on horse usage: the equestrian sector, private owner sector, exhibition sector, and fattening sector. To evaluate the risk of disease spread within and between sectors accompanied by horse movements, a stochastic individual-based network model was developed based on a previous survey of horse movement patterns. Surveillance parameters such as targeting sectors and frequency of testing were added into the model to compare surveillance strategies. The disease spread heterogeneously among sectors. Infection occurred mainly in the equestrian sector; the infection was less disseminated in other sectors. Therefore, we considered that the equestrian sector posed a higher risk of disease dissemination within and between sectors through horse movements. However, surveillance strategies targeting only the equestrian sector were not effective enough for early detection of the disease. Alternatively, targeting horses that moved permanently and those in the private owner sector in addition to the equestrian sector is recommended to achieve effectiveness equivalent to that of the current surveillance. In terms of surveillance efficacy, by increasing the testing interval (once yearly to once every 3 years), this testing scheme could reduce the number of tested horses to 44% of the current surveillance, while maintaining almost equivalent effectiveness. Intensive strategies targeting high-risk populations are considered to enhance effectiveness and efficiency of surveillance. The approach in this study may be helpful in the decision-making process that is involved in setting up strategies for risk-based surveillance. Copyright © 2011 Elsevier B.V. All rights reserved.

Gas Generation Testing of Spherical Resorcinol-Formaldehyde (sRF) Resin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Colburn, Heather A.; Bryan, Samuel A.; Camaioni, Donald M.

This report describes gas generation testing of the spherical resorcinol-formaldehyde (sRF) resin that was conducted to support the technology maturation of the LAWPS facility. The current safety basis for the LAWPS facility is based primarily on two studies that had limited or inconclusive data sets. The two studies indicated a 40% increase in hydrogen generation rate of water (as predicted by the Hu model) with sRF resin over water alone. However, the previous studies did not test the range of conditions (process fluids and temperatures) that are expected in the LAWPS facility. Additionally, the previous studies did not obtain replicatemore » test results or comparable liquid-only control samples. All of the testing described in this report, conducted with water, 0.45M nitric acid, and waste simulants with and without sRF resin, returned hydrogen generation rates that are within the current safety basis for the facility of 1.4 times the Hu model output for water.« less

Evaluation of Two Crew Module Boilerplate Tests Using Newly Developed Calibration Metrics

NASA Technical Reports Server (NTRS)

Horta, Lucas G.; Reaves, Mercedes C.

2012-01-01

The paper discusses a application of multi-dimensional calibration metrics to evaluate pressure data from water drop tests of the Max Launch Abort System (MLAS) crew module boilerplate. Specifically, three metrics are discussed: 1) a metric to assess the probability of enveloping the measured data with the model, 2) a multi-dimensional orthogonality metric to assess model adequacy between test and analysis, and 3) a prediction error metric to conduct sensor placement to minimize pressure prediction errors. Data from similar (nearly repeated) capsule drop tests shows significant variability in the measured pressure responses. When compared to expected variability using model predictions, it is demonstrated that the measured variability cannot be explained by the model under the current uncertainty assumptions.

Investigating the feasibility of integrating pavement friction and texture depth data in modeling for INDOT PMS.

DOT National Transportation Integrated Search

2012-11-01

Under INDOTs current friction testing program, the friction is measured annually on interstates but only once every three years on noninterstate : roadways. The states Pavement Management System, however, would require current data if friction ...

A Model for Estimating Current and Future Timber Volume Loss from Stem Decay Caused by Heterobasidion annosum and Other Fungi in Stands of True Fir

Treesearch

Gregory M. Filip

1989-01-01

In 1979, an equation was developed to estimate the percentage of current and future timber volume loss due to stem decay caused by Heterobasidion annosum and other fungi in advance regeneration stands of grand and white fir in eastern Oregon and Washington. Methods for using and testing the equation are presented. Extensive testing in 1988 showed the...

Materials Properties Research at MSFC

NASA Technical Reports Server (NTRS)

Presson, Joan B.; Burdine, Robert (Technical Monitor)

2002-01-01

MSFC is currently planning, organizing and directing test coupon fabrication and subsequent CTE testing for two mirror materials of specific interest to the AMSD and NGST programs, Beryllium 0-30H (Be 0-30H) and Ultra Low Expansion glass (ULE). The ULE test coupons are being fabricated at MSFC from AMSD core residuals provided by Kodak, The Be 0-30H test coupons are being fabricated at Brush Wellman using residuals from the SBMD. Both sets of test coupons will be sent to a test vendor selected through the NASA competitive proposal process with the test results being provided by written report to MSFC by the end of the fiscal year. The test results will become model input data for the AMSD analysts, both MSFC and contractor, providing an enhancement to the historical CTE data currently available.

Design of permanent magnet eddy current brake for a small scaled electromagnetic launch model

NASA Astrophysics Data System (ADS)

Zhou, Shigui; Yu, Haitao; Hu, Minqiang; Huang, Lei

2012-04-01

A variable pole-pitch double-sided permanent magnet (PM) linear eddy current brake (LECB) is proposed for a small scaled electromagnetic launch model. A two-dimensional (2D) analytical steady state model is presented for the double-sided PM-LECB, and the expression for the braking force is derived. Based on the analytical model, the material and eddy current skin effect of the conducting plate are analyzed. Moreover, a variable pole-pitch double-sided PM-LECB is proposed for the effective braking of the moving plate. In addition, the braking force is predicted by finite element (FE) analysis, and the simulated results are in good agreement with the analytical model. Finally, a prototype is presented to test the braking profile for validation of the proposed design.

Predicting the Effects of Test Media in Ground-Based Propulsion Testing

NASA Technical Reports Server (NTRS)

Drummond, J. Philip; Danehy, Paul M.; Bivolaru, Daniel; Gaffney, Richard L.; Parker, Peter A.; Chelliah, Harsha K.; Cutler, Andrew D.; Givi, Peyman; Hassan, Hassan, A.

2006-01-01

This paper discusses the progress of work which began in mid-2004 sponsored by the Office of the Secretary of Defense (OSD) Test & Evaluation/Science & Technology (T&E/S&T) Program. The purpose of the work is to improve the state of the art of CFD capabilities for predicting the effects of the test media on the flameholding characteristics in scramjet engines. The program has several components including the development of advance algorithms and models for simulating engine flowpaths as well as a fundamental experimental and diagnostic development effort to support the formulation and validation of the mathematical models. The paper will provide details of current work involving the development of phenomenological models for Reynolds averaged Navier-Stokes codes, large-eddy simulation techniques and reduced-kinetics models. Experiments that will provide data for the modeling efforts will also be described, along with with the associated nonintrusive diagnostics used to collect the data.

The relationship between Q gamma and Ca release from the sarcoplasmic reticulum in skeletal muscle

PubMed Central

1991-01-01

Asymmetric membrane currents and fluxes of Ca2+ release were determined in skeletal muscle fibers voltage clamped in a Vaseline-gap chamber. The conditioning pulse protocol 1 for suppressing Ca2+ release and the "hump" component of charge movement current (I gamma), described in the first paper of this series, was applied at different test pulse voltages. The amplitude of the current suppressed during the ON transient reached a maximum at slightly suprathreshold test voltages (- 50 to -40 mV) and decayed at higher voltages. The component of charge movement current suppressed by 20 microM tetracaine also went through a maximum at low pulse voltages. This anomalous voltage dependence is thus a property of I gamma, defined by either the conditioning protocol or the tetracaine effect. A negative (inward-going) phase was often observed in the asymmetric current during the ON of depolarizing pulses. This inward phase was shown to be an intramembranous charge movement based on (a) its presence in the records of total membrane current, (b) its voltage dependence, with a maximum at slightly suprathreshold voltages, (c) its association with a "hump" in the asymmetric current, (d) its inhibition by interventions that reduce the "hump", (e) equality of ON and OFF areas in the records of asymmetric current presenting this inward phase, and (f) its kinetic relationship with the time derivative of Ca release flux. The nonmonotonic voltage dependence of the amplitude of the hump and the possibility of an inward phase of intramembranous charge movement are used as the main criteria in the quantitative testing of a specific model. According to this model, released Ca2+ binds to negatively charged sites on the myoplasmic face of the voltage sensor and increases the local transmembrane potential, thus driving additional charge movement (the hump). This model successfully predicts the anomalous voltage dependence and all the kinetic properties of I gamma described in the previous papers. It also accounts for the inward phase in total asymmetric current and in the current suppressed by protocol 1. According to this model, I gamma accompanies activating transitions at the same set of voltage sensors as I beta. Therefore it should open additional release channels, which in turn should cause more I gamma, providing a positive feedback mechanism in the regulation of calcium release. PMID:1650812

Tests of chameleon gravity

NASA Astrophysics Data System (ADS)

Burrage, Clare; Sakstein, Jeremy

2018-03-01

Theories of modified gravity, where light scalars with non-trivial self-interactions and non-minimal couplings to matter—chameleon and symmetron theories—dynamically suppress deviations from general relativity in the solar system. On other scales, the environmental nature of the screening means that such scalars may be relevant. The highly-nonlinear nature of screening mechanisms means that they evade classical fifth-force searches, and there has been an intense effort towards designing new and novel tests to probe them, both in the laboratory and using astrophysical objects, and by reinterpreting existing datasets. The results of these searches are often presented using different parametrizations, which can make it difficult to compare constraints coming from different probes. The purpose of this review is to summarize the present state-of-the-art searches for screened scalars coupled to matter, and to translate the current bounds into a single parametrization to survey the state of the models. Presently, commonly studied chameleon models are well-constrained but less commonly studied models have large regions of parameter space that are still viable. Symmetron models are constrained well by astrophysical and laboratory tests, but there is a desert separating the two scales where the model is unconstrained. The coupling of chameleons to photons is tightly constrained but the symmetron coupling has yet to be explored. We also summarize the current bounds on f( R) models that exhibit the chameleon mechanism (Hu and Sawicki models). The simplest of these are well constrained by astrophysical probes, but there are currently few reported bounds for theories with higher powers of R. The review ends by discussing the future prospects for constraining screened modified gravity models further using upcoming and planned experiments.

By-Pass Diode Temperature Tests of a Solar Array Coupon under Space Thermal Environment Conditions

NASA Technical Reports Server (NTRS)

Wright, Kenneth H.; Schneider, Todd A.; Vaughn, Jason A.; Hoang, Bao; Wong, Frankie; Wu, Gordon

2016-01-01

By-Pass diodes are a key design feature of solar arrays and system design must be robust against local heating, especially with implementation of larger solar cells. By-Pass diode testing was performed to aid thermal model development for use in future array designs that utilize larger cell sizes that result in higher string currents. Testing was performed on a 56-cell Advanced Triple Junction solar array coupon provided by SSL. Test conditions were vacuum with cold array backside using discrete by-pass diode current steps of 0.25 A ranging from 0 A to 2.0 A.

Current collection from the space plasma through defects in solar array insulation

NASA Technical Reports Server (NTRS)

Robinson, R. S.; Stillwell, R. P.; Kaufman, H. R.

1985-01-01

Operating high-voltage solar arrays in the space environment can result in anomalously large currents being collected through small insulation defects. Tests simulating the electron collection have shown that there are two major collection modes. The first involves current enhancement by means of a surface phenomenon involving secondary electron emission from the surrounding insulator. In the second mode, the current collection is enhanced by vaporization and ionization of the insulator material, in addition to the surface enhancement of the first mode. The electron collection due to surface enhancement (first mode) has been modeled. Using this model, simple calculations yield realistic predictions.

Validation of the 5th and 95th Percentile Hybrid III Anthropomorphic Test Device Finite Element Model

NASA Technical Reports Server (NTRS)

Lawrence, C.; Somers, J. T.; Baldwin, M. A.; Wells, J. A.; Newby, N.; Currie, N. J.

2014-01-01

NASA spacecraft design requirements for occupant protection are a combination of the Brinkley criteria and injury metrics extracted from anthropomorphic test devices (ATD's). For the ATD injury metrics, the requirements specify the use of the 5th percentile female Hybrid III and the 95th percentile male Hybrid III. Furthermore, each of these ATD's is required to be fitted with an articulating pelvis and a straight spine. The articulating pelvis is necessary for the ATD to fit into spacecraft seats, while the straight spine is required as injury metrics for vertical accelerations are better defined for this configuration. The requirements require that physical testing be performed with both ATD's to demonstrate compliance. Before compliance testing can be conducted, extensive modeling and simulation are required to determine appropriate test conditions, simulate conditions not feasible for testing, and assess design features to better ensure compliance testing is successful. While finite element (FE) models are currently available for many of the physical ATD's, currently there are no complete models for either the 5th percentile female or the 95th percentile male Hybrid III with a straight spine and articulating pelvis. The purpose of this work is to assess the accuracy of the existing Livermore Software Technology Corporation's FE models of the 5th and 95th percentile ATD's. To perform this assessment, a series of tests will be performed at Wright Patterson Air Force Research Lab using their horizontal impact accelerator sled test facility. The ATD's will be placed in the Orion seat with a modified-advanced-crew-escape-system (MACES) pressure suit and helmet, and driven with loadings similar to what is expected for the actual Orion vehicle during landing, launch abort, and chute deployment. Test data will be compared to analytical predictions and modelling uncertainty factors will be determined for each injury metric. Additionally, the test data will be used to further improve the FE model, particularly in the areas of the ATD neck components, harness, and suit and helmet effects.

Ship Model Testing

DTIC Science & Technology

2016-01-15

state-of-the-art equipment and to continue to produce excellent graduates in our field. Technical Approach In order to address our current testing ...New Additions • New material testing machine with environmental chamber • New dual-fuel test bed for Haeberle Laboratory • Upgrade existing...Southwark Emery universal test machine • 3D printer with ultra-high surface definition • CFD Workstations Since the inception of this grant, Webb

Investigation of Keeper Erosion in the NSTAR Ion Thruster

NASA Technical Reports Server (NTRS)

Domonkos, Matthew T.; Foster, John E.; Patterson, Michael J.; Williams, George J., Jr.

2001-01-01

The goal of the present investigation was to determine the cause for the difference in the observed discharge keeper erosion between the 8200 hr wear test of a NASA Solar Electric Propulsion Technology Applications Readiness (NSTAR) engineering model thruster and the ongoing extended life test (ELT) of the NSTAR flight spare thruster. During the ELT, the NSTAR flight spare ion thruster experienced unanticipated erosion of the discharge cathode keeper. Photographs of the discharge keeper show that the orifice has enlarged to slightly more than twice the original diameter. Several differences between the ELT and the 8200 hr wear test were initially identified to determine any effects which could lead to the erosion in the ELT. In order to identify the cause of the ELT erosion, emission spectra from an engineering model thruster were collected to assess the dependence of keeper erosion on operating conditions. Keeper ion current was measured to estimate wear. Additionally, post-test inspection of both a copper keeper-cap was conducted, and the results are presented. The analysis indicated that the bulk of the ion current was collected within 2-mm radially of the orifice. The estimated volumetric wear in the ELT was comparable to previous wear tests. Redistribution of the ion current on the discharge keeper was determined to be the most likely cause of the ELT erosion. The change in ion current distribution was hypothesized to caused by the modified magnetic field of the flight assemblies.

Thematic mapper flight model preshipment review data package. Volume 4: Appendix. Part C: Power supply data

NASA Technical Reports Server (NTRS)

1982-01-01

The acceptance test data package for the thematic mapper flight model power supply was reviewed and the data compared to the relevant specification. The power supply was found to be within specification. Final test data for outut voltage regulation and ripple, efficiency, over and undervoltage protection, telemetry, impedances, turn-on requirements, and input current limits are presented.

Some Issues in Item Response Theory: Dimensionality Assessment and Models for Guessing

ERIC Educational Resources Information Center

Smith, Jessalyn

2009-01-01

Currently, standardized tests are widely used as a method to measure how well schools and students meet academic standards. As a result, measurement issues have become an increasingly popular topic of study. Unidimensional item response models are used to model latent abilities and specific item characteristics. This class of models makes…

The HEXACO and Five-Factor Models of Personality in Relation to RIASEC Vocational Interests

ERIC Educational Resources Information Center

McKay, Derek A.; Tokar, David M.

2012-01-01

The current study extended the empirical research on the overlap of vocational interests and personality by (a) testing hypothesized relations between RIASEC interests and the personality dimensions of the HEXACO model, and (b) exploring the HEXACO personality model's predictive advantage over the five-factor model (FFM) in capturing RIASEC…

Mental Models: Understanding the Impact of Fantasy Violence on Children's Moral Reasoning.

ERIC Educational Resources Information Center

Krcmar, Marina; Curtis, Stephen

2003-01-01

Tests the efficacy of mental models in understanding the effect of exposure to fantasy violence on children's responses to and reasoning about moral dilemmas involving aggression. Offers a possible extension to mental models that is consistent with current theory in cognitive science. Suggests that the activation of mental models regarding…

Analysis of the potential for point-of-care test to enable individualised treatment of infections caused by antimicrobial-resistant and susceptible strains of Neisseria gonorrhoeae: a modelling study.

PubMed

Turner, Katy Me; Christensen, Hannah; Adams, Elisabeth J; McAdams, David; Fifer, Helen; McDonnell, Anthony; Woodford, Neil

2017-06-14

To create a mathematical model to investigate the treatment impact and economic implications of introducing an antimicrobial resistance point-of-care test (AMR POCT) for gonorrhoea as a way of extending the life of current last-line treatments. Modelling study. England. Patients accessing sexual health services. Incremental impact of introducing a hypothetical AMR POCT that could detect susceptibility to previous first-line antibiotics, for example, ciprofloxacin or penicillin, so that patients are given more tailored treatment, compared with the current situation where all patients are given therapy with ceftriaxone and azithromycin. The hypothetical intervention was assessed using a mathematical model developed in Excel. The model included initial and follow-up attendances, loss to follow-up, use of standard or tailored treatment, time taken to treatment and the costs of testing and treatment. Number of doses of ceftriaxone saved, mean time to most appropriate treatment, mean number of visits per (infected) patient, number of patients lost to follow-up and total cost of testing. In the current situation, an estimated 33 431 ceftriaxone treatments are administered annually and 792 gonococcal infections remain untreated due to loss to follow-up. The use of an AMR POCT for ciprofloxacin could reduce these ceftriaxone treatments by 66%, and for an AMR POCT for penicillin by 79%. The mean time for patients receiving an antibiotic treatment is reduced by 2 days in scenarios including POCT and no positive patients remain untreated through eliminating loss to follow-up. Such POCTs are estimated to add £34 million to testing costs, but this does not take into account reductions in costs of repeat attendances and the reuse of older, cheaper antimicrobials. The introduction of AMR POCT could allow clinicians to discern between the majority of gonorrhoea-positive patients with strains that could be treated with older, previously abandoned first-line treatments, and those requiring our current last-line dual therapy. Such tests could extend the useful life of dual ceftriaxone and azithromycin therapy, thus pushing back the time when gonorrhoea may become untreatable. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Analysis of the potential for point-of-care test to enable individualised treatment of infections caused by antimicrobial-resistant and susceptible strains of Neisseria gonorrhoeae: a modelling study

PubMed Central

Christensen, Hannah; Adams, Elisabeth J; McAdams, David; Fifer, Helen; McDonnell, Anthony; Woodford, Neil

2017-01-01

Objective To create a mathematical model to investigate the treatment impact and economic implications of introducing an antimicrobial resistance point-of-care test (AMR POCT) for gonorrhoea as a way of extending the life of current last-line treatments. Design Modelling study. Setting England. Population Patients accessing sexual health services. Interventions Incremental impact of introducing a hypothetical AMR POCT that could detect susceptibility to previous first-line antibiotics, for example, ciprofloxacin or penicillin, so that patients are given more tailored treatment, compared with the current situation where all patients are given therapy with ceftriaxone and azithromycin. The hypothetical intervention was assessed using a mathematical model developed in Excel. The model included initial and follow-up attendances, loss to follow-up, use of standard or tailored treatment, time taken to treatment and the costs of testing and treatment. Main outcome measures Number of doses of ceftriaxone saved, mean time to most appropriate treatment, mean number of visits per (infected) patient, number of patients lost to follow-up and total cost of testing. Results In the current situation, an estimated 33 431 ceftriaxone treatments are administered annually and 792 gonococcal infections remain untreated due to loss to follow-up. The use of an AMR POCT for ciprofloxacin could reduce these ceftriaxone treatments by 66%, and for an AMR POCT for penicillin by 79%. The mean time for patients receiving an antibiotic treatment is reduced by 2 days in scenarios including POCT and no positive patients remain untreated through eliminating loss to follow-up. Such POCTs are estimated to add £34 million to testing costs, but this does not take into account reductions in costs of repeat attendances and the reuse of older, cheaper antimicrobials. Conclusions The introduction of AMR POCT could allow clinicians to discern between the majority of gonorrhoea-positive patients with strains that could be treated with older, previously abandoned first-line treatments, and those requiring our current last-line dual therapy. Such tests could extend the useful life of dual ceftriaxone and azithromycin therapy, thus pushing back the time when gonorrhoea may become untreatable. PMID:28615273

Motor Vehicle Demand Models : Assessment of the State of the Art and Directions for Future Research

DOT National Transportation Integrated Search

1981-04-01

The report provides an assessment of the current state of motor vehicle demand modeling. It includes a detailed evaluation of one leading large-scale econometric vehicle demand model, which is tested for both logical consistency and forecasting accur...

Advanced decision modeling for real time variable tolling : development and testing of a data collection platform.

DOT National Transportation Integrated Search

2012-06-01

Our current ability to forecast demand on tolled facilities has not kept pace with advances in decision sciences and : technological innovation. The current forecasting methods suffer from lack of descriptive power of actual behavior because : of the...

A forecast experiment of earthquake activity in Japan under Collaboratory for the Study of Earthquake Predictability (CSEP)

NASA Astrophysics Data System (ADS)

Hirata, N.; Yokoi, S.; Nanjo, K. Z.; Tsuruoka, H.

2012-04-01

One major focus of the current Japanese earthquake prediction research program (2009-2013), which is now integrated with the research program for prediction of volcanic eruptions, is to move toward creating testable earthquake forecast models. For this purpose we started an experiment of forecasting earthquake activity in Japan under the framework of the Collaboratory for the Study of Earthquake Predictability (CSEP) through an international collaboration. We established the CSEP Testing Centre, an infrastructure to encourage researchers to develop testable models for Japan, and to conduct verifiable prospective tests of their model performance. We started the 1st earthquake forecast testing experiment in Japan within the CSEP framework. We use the earthquake catalogue maintained and provided by the Japan Meteorological Agency (JMA). The experiment consists of 12 categories, with 4 testing classes with different time spans (1 day, 3 months, 1 year, and 3 years) and 3 testing regions called "All Japan," "Mainland," and "Kanto." A total of 105 models were submitted, and are currently under the CSEP official suite of tests for evaluating the performance of forecasts. The experiments were completed for 92 rounds for 1-day, 6 rounds for 3-month, and 3 rounds for 1-year classes. For 1-day testing class all models passed all the CSEP's evaluation tests at more than 90% rounds. The results of the 3-month testing class also gave us new knowledge concerning statistical forecasting models. All models showed a good performance for magnitude forecasting. On the other hand, observation is hardly consistent in space distribution with most models when many earthquakes occurred at a spot. Now we prepare the 3-D forecasting experiment with a depth range of 0 to 100 km in Kanto region. The testing center is improving an evaluation system for 1-day class experiment to finish forecasting and testing results within one day. The special issue of 1st part titled Earthquake Forecast Testing Experiment in Japan was published on the Earth, Planets and Space Vol. 63, No.3, 2011 on March, 2011. The 2nd part of this issue, which is now on line, will be published soon. An outline of the experiment and activities of the Japanese Testing Center are published on our WEB site; http://wwweic.eri.u-tokyo.ac.jp/ZISINyosoku/wiki.en/wiki.cgi

Current-induced dissipation in spectral wave models

NASA Astrophysics Data System (ADS)

Rapizo, H.; Babanin, A. V.; Provis, D.; Rogers, W. E.

2017-03-01

Despite many recent developments of the parameterization for wave dissipation in spectral models, it is evident that when waves propagate onto strong adverse currents the rate of energy dissipation is not properly estimated. The issue of current-induced dissipation is studied through a comprehensive data set in the tidal inlet of Port Phillip Heads, Australia. The wave parameters analyzed are significantly modulated by the tidal currents. Wave height in conditions of opposing currents (ebb tide) can reach twice the offshore value, whereas during coflowing currents (flood), it can be reduced to half. The wind-wave model SWAN is able to reproduce the tide-induced modulation of waves and the results show that the variation of currents is the dominant factor in modifying the wave field. In stationary simulations, the model provides an accurate representation of wave height for slack and flood tides. During ebb tides, wave energy is highly overestimated over the opposing current jet. None of the four parameterizations for wave dissipation tested performs satisfactorily. A modification to enhance dissipation as a function of the local currents is proposed. It consists of the addition of a factor that represents current-induced wave steepening and it is scaled by the ratio of spectral energy to the threshold breaking level. The new term asymptotes to the original form as the current in the wave direction tends to zero. The proposed modification considerably improves wave height and mean period in conditions of adverse currents, whereas the good model performance in coflowing currents is unaltered.

Dynamic Performance Investigation of A Spar-Type Floating Wind Turbine Under Different Sea Conditions

NASA Astrophysics Data System (ADS)

Wang, Han; Hu, Zhi-qiang; Meng, Xiang-yin

2018-06-01

Both numerical calculation and model test are important techniques to study and forecast the dynamic responses of the floating offshore wind turbine (FOWT). However, both the methods have their own limitations at present. In this study, the dynamic responses of a 5 MW OC3 spar-type floating wind turbine designed for a water depth of 200 m are numerically investigated and validated by a 1:50 scaled model test. Moreover, the discrepancies between the numerical calculations and model tests are obtained and discussed. According to the discussions, it is found that the surge and pitch are coupled with the mooring tensions, but the heave is independent of them. Surge and pitch are mainly induced by wave under wind wave conditions. Wind and current will induce the low-frequency average responses, while wave will induce the fluctuation ranges of the responses. In addition, wave will induce the wavefrequency responses but wind and current will restrain the ranges of the responses.

The SIETTE Automatic Assessment Environment

ERIC Educational Resources Information Center

Conejo, Ricardo; Guzmán, Eduardo; Trella, Monica

2016-01-01

This article describes the evolution and current state of the domain-independent Siette assessment environment. Siette supports different assessment methods--including classical test theory, item response theory, and computer adaptive testing--and integrates them with multidimensional student models used by intelligent educational systems.…

Immunotoxicant screening and prioritization in the 21st century

EPA Science Inventory

Current immunotoxicity testing guidance for drugs, high production volume chemicals and pesticides specifies the use of animal models that measure immune function or evaluation of general indicators of immune system health generated in routine toxicity testing. The assays are ...

Immunotoxicant screening and prioritization in the 21st century*

EPA Science Inventory

Current immunotoxicity testing guidance for drugs, high production volume chemicals and pesticides specifies the use of animal models that measure immune function or evaluation of general indicators of immune system health generated in routine toxicity testing. The assays are r...

The Sandia transportable triggered lightning instrumentation facility

NASA Technical Reports Server (NTRS)

Schnetzer, George H.; Fisher, Richard J.

1991-01-01

Development of the Sandia Transportable Triggered Lightning Instrumentation Facility (SATTLIF) was motivated by a requirement for the in situ testing of a munitions storage bunker. Transfer functions relating the incident flash currents to voltages, currents, and electromagnetic field values throughout the structure will be obtained for use in refining and validating a lightning response computer model of this type of structure. A preliminary shakedown trial of the facility under actual operational conditions was performed during summer of 1990 at the Kennedy Space Center's (KSC) rocket-triggered lightning test site. A description is given of the SATTLIF, which is readily transportable on a single flatbed truck of by aircraft, and its instrumentation for measuring incident lightning channel currents and the responses of the systems under test. Measurements of return-stroke current peaks obtained with the SATTLIF are presented. Agreement with data acquired on the same flashes with existing KSC instrumentation is, on average, to within approximately 7 percent. Continuing currents were measured with a resolution of approximately 2.5 A. This field trial demonstrated the practicality of using a transportable triggered lightning facility for specialized test applications.

Measurement of positive direct current corona pulse in coaxial wire-cylinder gap

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yin, Han, E-mail: hanyin1986@gmail.com; Zhang, Bo, E-mail: shizbcn@mail.tsinghua.edu.cn; He, Jinliang, E-mail: hejl@tsinghua.edu.cn

In this paper, a system is designed and developed to measure the positive corona current in coaxial wire-cylinder gaps. The characteristic parameters of corona current pulses, such as the amplitude, rise time, half-wave time, and repetition frequency, are statistically analyzed and a new set of empirical formulas are derived by numerical fitting. The influence of space charges on corona currents is tested by using three corona cages with different radii. A numerical method is used to solve a simplified ion-flow model to explain the influence of space charges. Based on the statistical results, a stochastic model is developed to simulatemore » the corona pulse trains. And this model is verified by comparing the simulated frequency-domain responses with the measured ones.« less

CAPTIONALS: A computer aided testing environment for the verification and validation of communication protocols

NASA Technical Reports Server (NTRS)

Feng, C.; Sun, X.; Shen, Y. N.; Lombardi, Fabrizio

1992-01-01

This paper covers the verification and protocol validation for distributed computer and communication systems using a computer aided testing approach. Validation and verification make up the so-called process of conformance testing. Protocol applications which pass conformance testing are then checked to see whether they can operate together. This is referred to as interoperability testing. A new comprehensive approach to protocol testing is presented which address: (1) modeling for inter-layer representation for compatibility between conformance and interoperability testing; (2) computational improvement to current testing methods by using the proposed model inclusive of formulation of new qualitative and quantitative measures and time-dependent behavior; (3) analysis and evaluation of protocol behavior for interactive testing without extensive simulation.

Development of a model for occipital fixation--validation of an analogue bone material.

PubMed

Mullett, H; O'Donnell, T; Felle, P; O'Rourke, K; FitzPatrick, D

2002-01-01

Several implant systems may be used to fuse the skull to the upper cervical spine (occipitocervical fusion). Current biomechanical evaluation is restricted by the limitations of human cadaveric specimens. This paper describes the design and validation of a synthetic testing model of the occipital bone. Data from thickness measurement and pull-out strength testing of a series of human cadaveric skulls was used in the design of a high-density rigid polyurethane foam model. The synthetic occipital model demonstrated repeatable and consistent morphological and biomechanical properties. The model provides a standardized environment for evaluation of occipital implants.

Effect of roughness formulation on the performance of a coupled wave, hydrodynamic, and sediment transport model

USGS Publications Warehouse

Ganju, Neil K.; Sherwood, Christopher R.

2010-01-01

A variety of algorithms are available for parameterizing the hydrodynamic bottom roughness associated with grain size, saltation, bedforms, and wave–current interaction in coastal ocean models. These parameterizations give rise to spatially and temporally variable bottom-drag coefficients that ostensibly provide better representations of physical processes than uniform and constant coefficients. However, few studies have been performed to determine whether improved representation of these variable bottom roughness components translates into measurable improvements in model skill. We test the hypothesis that improved representation of variable bottom roughness improves performance with respect to near-bed circulation, bottom stresses, or turbulence dissipation. The inner shelf south of Martha’s Vineyard, Massachusetts, is the site of sorted grain-size features which exhibit sharp alongshore variations in grain size and ripple geometry over gentle bathymetric relief; this area provides a suitable testing ground for roughness parameterizations. We first establish the skill of a nested regional model for currents, waves, stresses, and turbulent quantities using a uniform and constant roughness; we then gauge model skill with various parameterization of roughness, which account for the influence of the wave-boundary layer, grain size, saltation, and rippled bedforms. We find that commonly used representations of ripple-induced roughness, when combined with a wave–current interaction routine, do not significantly improve skill for circulation, and significantly decrease skill with respect to stresses and turbulence dissipation. Ripple orientation with respect to dominant currents and ripple shape may be responsible for complicating a straightforward estimate of the roughness contribution from ripples. In addition, sediment-induced stratification may be responsible for lower stresses than predicted by the wave–current interaction model.

Effect of Surge Current Testing on Reliability of Solid Tantalum Capacitors

NASA Technical Reports Server (NTRS)

Teverovsky, Alexander

2008-01-01

Tantalum capacitors manufactured per military specifications are established reliability components and have less than 0.001% of failures per 1000 hours for grades D or S, thus positioning these parts among electronic components with the highest reliability characteristics. Still, failures of tantalum capacitors do happen and when it occurs it might have catastrophic consequences for the system. To reduce this risk, further development of a screening and qualification system with special attention to the possible deficiencies in the existing procedures is necessary. The purpose of this work is evaluation of the effect of surge current stress testing on reliability of the parts at both steady-state and multiple surge current stress conditions. In order to reveal possible degradation and precipitate more failures, various part types were tested and stressed in the range of voltage and temperature conditions exceeding the specified limits. A model to estimate the probability of post-surge current testing-screening failures and measures to improve the effectiveness of the screening process has been suggested.

Experimental and Numerical Study on the Deformation Mechanism in AZ31B Mg Alloy Sheets Under Pulsed Electric-Assisted Tensile and Compressive Tests

NASA Astrophysics Data System (ADS)

Lee, Jinwoo; Kim, Se-Jong; Lee, Myoung-Gyu; Song, Jung Han; Choi, Seogou; Han, Heung Nam; Kim, Daeyong

2016-06-01

The uniaxial tensile and compressive stress-strain responses of AZ31B magnesium alloy sheet under pulsed electric current are reported. Tension and compression tests with pulsed electric current showed that flow stresses dropped instantaneously when the electric pulses were applied. Thermo-mechanical-electrical finite element analyses were also performed to investigate the effects of Joule heating and electro-plasticity on the flow responses of AZ31B sheets under electric-pulsed tension and compression tests. The proposed finite element simulations could reproduce the measured uniaxial tensile and compressive stress-strain curves under pulsed electric currents, when the temperature-dependent flow stress hardening model and thermal properties of AZ31B sheet were properly described in the simulations. In particular, the simulation results that fit best with experimental results showed that almost 100 pct of the electric current was subject to transform into Joule heating during electrically assisted tensile and compressive tests.

Design and test of 1/5th scale horizontal axis tidal current turbine

NASA Astrophysics Data System (ADS)

Liu, Hong-wei; Zhou, Hong-bin; Lin, Yong-gang; Li, Wei; Gu, Hai-gang

2016-06-01

Tidal current energy is prominent and renewable. Great progress has been made in the exploitation technology of tidal current energy all over the world in recent years, and the large scale device has become the trend of tidal current turbine (TCT) for its economies. Instead of the similarity to the wind turbine, the tidal turbine has the characteristics of high hydrodynamic efficiency, big thrust, reliable sealing system, tight power transmission structure, etc. In this paper, a 1/5th scale horizontal axis tidal current turbine has been designed, manufactured and tested before the full scale device design. Firstly, the three-blade horizontal axis rotor was designed based on traditional blade element momentum theory and its hydrodynamic performance was predicted in numerical model. Then the power train system and stand-alone electrical control unit of tidal current turbine, whose performances were accessed through the bench test carried out in workshop, were designed and presented. Finally, offshore tests were carried out and the power performance of the rotor was obtained and compared with the published literatures, and the results showed that the power coefficient was satisfactory, which agrees with the theoretical predictions.

Theoretical modeling of the MILES hit profiles in military weapon low-data rate simulators

NASA Astrophysics Data System (ADS)

Andrews, L. C.; Phillips, R. L.; Smith, C. A.; Belichki, S. B.; Crabbs, R.; Cofarro, J. T.; Fountain, W.; Tucker, F. M.; Parrish, B. J.

2016-09-01

Math modeling of a low-data-rate optical communication system is presented and compared with recent testing results over ranges up to 100 m in an indoor tunnel at Kennedy Space Center. Additional modeling of outdoor testing results at longer ranges in the open atmosphere is also presented. The system modeled is the Army's Multiple Integrated Laser Engagement System (MILES) that has been used as a tactical training system since the early 1980s. The objective of the current modeling and testing is to obtain target hit zone profiles for the M16A2/M4 rifles and establish a data baseline for MILES that will aid in its upgrade using more recently developed lasers and detectors.

International Space Station Cathode Life Testing

NASA Technical Reports Server (NTRS)

Soulas, George C.; Sarver-Verhey, Timothy R.

1997-01-01

Four hollow cathode assembly (HCA) life tests were initiated at operating conditions simulating on-orbit operation of the International Space Station plasma contactor. The objective of these tests is to demonstrate the mission-required 18,000 hour lifetime with high-fidelity development model HCAS. HCAs are operated with a continuous 6 sccm xenon flow rate and 3 A anode current. On-orbit emission current requirements are simulated with a square waveform consisting of 50 minutes at a 2.5 A emission current and 40 minutes with no emission current. One HCA test was terminated after approximately 8,000 hours so that a destructive analysis could be performed. The analysis revealed no life-limiting processes and the ultimate lifetime was projected to be greater than the mission requirement. Testing continues for the remaining three HCAs which have accumulated approximately 8,000 hours, 10,000 hours, and 11,000 hours, respectively, as of June 1997. Anode and bias voltages, strong indicators of cathode electron emitter condition, are within acceptable ranges and have exhibited no life- or performance-limiting phenomena to date.

USE OF THE LABORATORY RAT AS A MODEL IN ENDOCRINE DISRUPTOR SCREENING AND TESTING

EPA Science Inventory

The screening and testing program the US Environmental Protection Agency is currently developing to detect endocrine-disrupting chemicals (EDCs) is described. EDCs have been shown to alter the following activities: hypothalamic-pituitary-gonadal [HPG] function; estrogen, androge...

Frequentist Model Averaging in Structural Equation Modelling.

PubMed

Jin, Shaobo; Ankargren, Sebastian

2018-06-04

Model selection from a set of candidate models plays an important role in many structural equation modelling applications. However, traditional model selection methods introduce extra randomness that is not accounted for by post-model selection inference. In the current study, we propose a model averaging technique within the frequentist statistical framework. Instead of selecting an optimal model, the contributions of all candidate models are acknowledged. Valid confidence intervals and a [Formula: see text] test statistic are proposed. A simulation study shows that the proposed method is able to produce a robust mean-squared error, a better coverage probability, and a better goodness-of-fit test compared to model selection. It is an interesting compromise between model selection and the full model.

Eddy current testing for blade edge micro cracks of aircraft engine

NASA Astrophysics Data System (ADS)

Zhang, Wei-min; Xu, Min-dong; Gao, Xuan-yi; Jin, Xin; Qin, Feng

2017-10-01

Based on the problems of low detection efficiency in the micro cracks detection of aircraft engine blades, a differential excitation eddy current testing system was designed and developed. The function and the working principle of the system were described, the problems which contained the manufacture method of simulated cracks, signal generating, signal processing and the signal display method were described. The detection test was carried out by taking a certain model aircraft engine blade with simulated cracks as a tested specimen. The test data was processed by digital low-pass filter in the computer and the crack signals of time domain display and Lissajous figure display were acquired. By comparing the test results, it is verified that Lissajous figure display shows better performance compared to time domain display when the crack angle is small. The test results show that the eddy current testing system designed in this paper is feasible to detect the micro cracks on the aeroengine blade and can effectively improve the detection efficiency of micro cracks in the practical detection work.

NASA GRC and MSFC Space-Plasma Arc Testing Procedures

NASA Technical Reports Server (NTRS)

Ferguson, Dale C.; Vayner, Boris V.; Galofaro, Joel T,; Hillard, G. Barry; Vaughn, Jason; Schneider, Todd

2005-01-01

Tests of arcing and current collection in simulated space plasma conditions have been performed at the NASA Glenn Research Center (GRC) in Cleveland, Ohio, for over 30 years and at the Marshall Space Flight Center (MSFC) in Huntsville, Alabama, for almost as long. During this period, proper test conditions for accurate and meaningful space simulation have been worked out, comparisons with actual space performance in spaceflight tests and with real operational satellites have been made, and NASA has achieved our own internal standards for test protocols. It is the purpose of this paper to communicate the test conditions, test procedures, and types of analysis used at NASA GRC and MSFC to the space environmental testing community at large, to help with international space-plasma arcing-testing standardization. To be discussed are: 1.Neutral pressures, neutral gases, and vacuum chamber sizes. 2. Electron and ion densities, plasma uniformity, sample sizes, and Debuy lengths. 3. Biasing samples versus self-generated voltages. Floating samples versus grounded. 4. Power supplies and current limits. Isolation of samples from power supplies during arcs. 5. Arc circuits. Capacitance during biased arc-threshold tests. Capacitance during sustained arcing and damage tests. Arc detection. Prevention sustained discharges during testing. 6. Real array or structure samples versus idealized samples. 7. Validity of LEO tests for GEO samples. 8. Extracting arc threshold information from arc rate versus voltage tests. 9. Snapover and current collection at positive sample bias. Glows at positive bias. Kapon (R) pyrolisis. 10. Trigger arc thresholds. Sustained arc thresholds. Paschen discharge during sustained arcing. 11. Testing for Paschen discharge threshold. Testing for dielectric breakdown thresholds. Testing for tether arcing. 12. Testing in very dense plasmas (ie thruster plumes). 13. Arc mitigation strategies. Charging mitigation strategies. Models. 14. Analysis of test results. Finally, the necessity of testing will be emphasized, not to the exclusion of modeling, but as part of a complete strategy for determining when and if arcs will occur, and preventing them from occurring in space.

NASA GRC and MSFC Space-Plasma Arc Testing Procedures

NASA Technical Reports Server (NTRS)

Ferguson, Dale C.a; Vayner, Boris V.; Galofaro, Joel T.; Hillard, G. Barry; Vaughn, Jason; Schneider, Todd

2005-01-01

Tests of arcing and current collection in simulated space plasma conditions have been performed at the NASA Glenn Research Center (GRC) in Cleveland, Ohio, for over 30 years and at the Marshall Space flight Center (MSFC) for almost as long. During this period, proper test conditions for accurate and meaningful space simulation have been worked out, comparisons with actual space performance in spaceflight tests and with real operational satellites have been made, and NASA has achieved our own internal standards for test protocols. It is the purpose of this paper to communicate the test conditions, test procedures, and types of analysis used at NASA GRC and MSFC to the space environmental testing community at large, to help with international space-plasma arcing testing standardization. To be discussed are: 1. Neutral pressures, neutral gases, and vacuum chamber sizes. 2. Electron and ion densities, plasma uniformity, sample sizes, and Debye lengths. 3. Biasing samples versus self-generated voltages. Floating samples versus grounded. 4. Power supplies and current limits. Isolation of samples from power supplies during arcs. Arc circuits. Capacitance during biased arc-threshold tests. Capacitance during sustained arcing and damage tests. Arc detection. Preventing sustained discharges during testing. 5. Real array or structure samples versus idealized samples. 6. Validity of LEO tests for GEO samples. 7. Extracting arc threshold information from arc rate versus voltage tests. 8 . Snapover and current collection at positive sample bias. Glows at positive bias. Kapton pyrolization. 9. Trigger arc thresholds. Sustained arc thresholds. Paschen discharge during sustained arcing. 10. Testing for Paschen discharge thresholds. Testing for dielectric breakdown thresholds. Testing for tether arcing. 11. Testing in very dense plasmas (ie thruster plumes). 12. Arc mitigation strategies. Charging mitigation strategies. Models. 13. Analysis of test results. Finally, the necessity of testing will be emphasized, not to the exclusion of modeling, but as part of a complete strategy for determining when and if arcs will occur, and preventing them from occurring in space.

History and Evolution of the Johnson Criteria.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sjaardema, Tracy A.; Smith, Collin S.; Birch, Gabriel Carisle

The Johnson Criteria metric calculates probability of detection of an object imaged by an optical system, and was created in 1958 by John Johnson. As understanding of target detection has improved, detection models have evolved to better model additional factors such as weather, scene content, and object placement. The initial Johnson Criteria, while sufficient for technology and understanding at the time, does not accurately reflect current research into target acquisition and technology. Even though current research shows a dependence on human factors, there appears to be a lack of testing and modeling of human variability.

Hybrid and plug-in hybrid electric vehicle performance testing by the US Department of Energy Advanced Vehicle Testing Activity

NASA Astrophysics Data System (ADS)

Karner, Donald; Francfort, James

The Advanced Vehicle Testing Activity (AVTA), part of the U.S. Department of Energy's FreedomCAR and Vehicle Technologies Program, has conducted testing of advanced technology vehicles since August 1995 in support of the AVTA goal to provide benchmark data for technology modeling, and vehicle development programs. The AVTA has tested full size electric vehicles, urban electric vehicles, neighborhood electric vehicles, and hydrogen internal combustion engine powered vehicles. Currently, the AVTA is conducting baseline performance, battery benchmark and fleet tests of hybrid electric vehicles (HEV) and plug-in hybrid electric vehicles (PHEV). Testing has included all HEVs produced by major automotive manufacturers and spans over 2.5 million test miles. Testing is currently incorporating PHEVs from four different vehicle converters. The results of all testing are posted on the AVTA web page maintained by the Idaho National Laboratory.

Random Vibration Testing of Advanced Wet Tantalum Capacitors

NASA Technical Reports Server (NTRS)

Teverovsky, Alexander

2015-01-01

Advanced wet tantalum capacitors allow for improved performance of power supply systems along with substantial reduction of size and weight of the systems that is especially beneficial for space electronics. Due to launch-related stresses, acceptance testing of all space systems includes random vibration test (RVT). However, many types of advanced wet tantalum capacitors cannot pass consistently RVT at conditions specified in MIL-PRF-39006, which impedes their use in space projects. This requires a closer look at the existing requirements, modes and mechanisms of failures, specifics of test conditions, and acceptance criteria. In this work, different lots of advanced wet tantalum capacitors from four manufacturers have been tested at step stress random vibration conditions while their currents were monitored before, during, and after the testing. It has been shown that the robustness of the parts and their reliability are mostly due to effective self-healing processes and limited current spiking or minor scintillations caused by RVT do not increase the risk of failures during operation. A simple model for scintillations events has been used to simulate current spiking during RVT and optimize test conditions. The significance of scintillations and possible effects of gas generation have been discussed and test acceptance criteria for limited current spiking have been suggested.

An Approximation to the Adaptive Exponential Integrate-and-Fire Neuron Model Allows Fast and Predictive Fitting to Physiological Data.

PubMed

Hertäg, Loreen; Hass, Joachim; Golovko, Tatiana; Durstewitz, Daniel

2012-01-01

For large-scale network simulations, it is often desirable to have computationally tractable, yet in a defined sense still physiologically valid neuron models. In particular, these models should be able to reproduce physiological measurements, ideally in a predictive sense, and under different input regimes in which neurons may operate in vivo. Here we present an approach to parameter estimation for a simple spiking neuron model mainly based on standard f-I curves obtained from in vitro recordings. Such recordings are routinely obtained in standard protocols and assess a neuron's response under a wide range of mean-input currents. Our fitting procedure makes use of closed-form expressions for the firing rate derived from an approximation to the adaptive exponential integrate-and-fire (AdEx) model. The resulting fitting process is simple and about two orders of magnitude faster compared to methods based on numerical integration of the differential equations. We probe this method on different cell types recorded from rodent prefrontal cortex. After fitting to the f-I current-clamp data, the model cells are tested on completely different sets of recordings obtained by fluctuating ("in vivo-like") input currents. For a wide range of different input regimes, cell types, and cortical layers, the model could predict spike times on these test traces quite accurately within the bounds of physiological reliability, although no information from these distinct test sets was used for model fitting. Further analyses delineated some of the empirical factors constraining model fitting and the model's generalization performance. An even simpler adaptive LIF neuron was also examined in this context. Hence, we have developed a "high-throughput" model fitting procedure which is simple and fast, with good prediction performance, and which relies only on firing rate information and standard physiological data widely and easily available.

Self-consistent radiation-based simulation of electric arcs: II. Application to gas circuit breakers

NASA Astrophysics Data System (ADS)

Iordanidis, A. A.; Franck, C. M.

2008-07-01

An accurate and robust method for radiative heat transfer simulation for arc applications was presented in the previous paper (part I). In this paper a self-consistent mathematical model based on computational fluid dynamics and a rigorous radiative heat transfer model is described. The model is applied to simulate switching arcs in high voltage gas circuit breakers. The accuracy of the model is proven by comparison with experimental data for all arc modes. The ablation-controlled arc model is used to simulate high current PTFE arcs burning in cylindrical tubes. Model accuracy for the lower current arcs is evaluated using experimental data on the axially blown SF6 arc in steady state and arc resistance measurements close to current zero. The complete switching process with the arc going through all three phases is also simulated and compared with the experimental data from an industrial circuit breaker switching test.

Cryogenic Optical Performance of a Light-weight Mirror Assembly for Future Space Astronomical Telescopes: Optical Test Results and Thermal Optical Model

NASA Technical Reports Server (NTRS)

Eng, Ron; Arnold, William; Baker, Markus A.; Bevan, Ryan M.; Carpenter, James R.; Effinger, Michael R.; Gaddy, Darrell E.; Goode, Brian K.; Kegley, Jeffrey R.; Hogue, William D.;

Jet-Surface Interaction - High Aspect Ratio Nozzle Test: Test Summary

NASA Technical Reports Server (NTRS)

Brown, Clifford A.

2016-01-01

The Jet-Surface Interaction High Aspect Ratio Nozzle Test was conducted in the Aero-Acoustic Propulsion Laboratory at the NASA Glenn Research Center in the fall of 2015. There were four primary goals specified for this test: (1) extend the current noise database for rectangular nozzles to higher aspect ratios, (2) verify data previously acquired at small-scale with data from a larger model, (3) acquired jet-surface interaction noise data suitable for creating verifying empirical noise models and (4) investigate the effect of nozzle septa on the jet-mixing and jet-surface interaction noise. These slides give a summary of the test with representative results for each goal.

Objectively-Measured Impulsivity and Attention-Deficit/Hyperactivity Disorder (ADHD): Testing Competing Predictions from the Working Memory and Behavioral Inhibition Models of ADHD

ERIC Educational Resources Information Center

Raiker, Joseph S.; Rapport, Mark D.; Kofler, Michael J.; Sarver, Dustin E.

2012-01-01

Impulsivity is a hallmark of two of the three DSM-IV ADHD subtypes and is associated with myriad adverse outcomes. Limited research, however, is available concerning the mechanisms and processes that contribute to impulsive responding by children with ADHD. The current study tested predictions from two competing models of ADHD--working memory (WM)…

Properties of a Formal Method to Model Emergence in Swarm-Based Systems

NASA Technical Reports Server (NTRS)

Rouff, Christopher; Vanderbilt, Amy; Truszkowski, Walt; Rash, James; Hinchey, Mike

2004-01-01

Future space missions will require cooperation between multiple satellites and/or rovers. Developers are proposing intelligent autonomous swarms for these missions, but swarm-based systems are difficult or impossible to test with current techniques. This viewgraph presentation examines the use of formal methods in testing swarm-based systems. The potential usefulness of formal methods in modeling the ANTS asteroid encounter mission is also examined.

Propfan experimental data analysis

NASA Technical Reports Server (NTRS)

Vernon, David F.; Page, Gregory S.; Welge, H. Robert

1984-01-01

A data reduction method, which is consistent with the performance prediction methods used for analysis of new aircraft designs, is defined and compared to the method currently used by NASA using data obtained from an Ames Res. Center 11 foot transonic wind tunnel test. Pressure and flow visualization data from the Ames test for both the powered straight underwing nacelle, and an unpowered contoured overwing nacelle installation is used to determine the flow phenomena present for a wind mounted turboprop installation. The test data is compared to analytic methods, showing the analytic methods to be suitable for design and analysis of new configurations. The data analysis indicated that designs with zero interference drag levels are achieveable with proper wind and nacelle tailoring. A new overwing contoured nacelle design and a modification to the wing leading edge extension for the current wind tunnel model design are evaluated. Hardware constraints of the current model parts prevent obtaining any significant performance improvement due to a modified nacelle contouring. A new aspect ratio wing design for an up outboard rotation turboprop installation is defined, and an advanced contoured nacelle is provided.

Analysis of High Power IGBT Short Circuit Failures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pappas, G.

2005-02-11

The Next Linear Collider (NLC) accelerator proposal at SLAC requires a highly efficient and reliable, low cost, pulsed-power modulator to drive the klystrons. A solid-state induction modulator has been developed at SLAC to power the klystrons; this modulator uses commercial high voltage and high current Insulated Gate Bipolar Transistor (IGBT) modules. Testing of these IGBT modules under pulsed conditions was very successful; however, the IGBTs failed when tests were performed into a low inductance short circuit. The internal electrical connections of a commercial IGBT module have been analyzed to extract self and mutual partial inductances for the main current pathsmore » as well as for the gate structure. The IGBT module, together with the partial inductances, has been modeled using PSpice. Predictions for electrical paths that carry the highest current correlate with the sites of failed die under short circuit tests. A similar analysis has been carried out for a SLAC proposal for an IGBT module layout. This paper discusses the mathematical model of the IGBT module geometry and presents simulation results.« less

Numerical Test of the Additivity Principle in Anomalous Transport

NASA Astrophysics Data System (ADS)

Tamaki, Shuji

2017-10-01

The additivity principle (AP) is one of the remarkable predictions that systematically generates all information on current fluctuations once the value of average current in the linear response regime is input. However, conditions to justify the AP are still ambiguous. We hence consider three tractable models, and discuss possible conditions. The models include the harmonic chain (HC), momentum exchange (ME) model, and momentum flip (MF) model, which respectively show ballistic, anomalous, and diffusive transport. We compare the heat current cumulants predicted by the AP with exact numerical data obtained for these models. The HC does not show the AP, whereas the MF model satisfies it, as expected, since the AP was originally proposed for diffusive systems. Surprisingly, the ME model also shows the AP. The ME model is known to show the anomalous transport similar to that shown in nonlinear systems such as the Fermi-Pasta-Ulam model. Our finding indicates that general nonlinear systems may satisfy the AP. Possible conditions for satisfying the AP are discussed.

Alternative Factor Models and Heritability of the Short Leyton Obsessional Inventory--Children's Version

ERIC Educational Resources Information Center

Moore, Janette; Smith, Gillian W.; Shevlin, Mark; O'Neill, Francis A.

2010-01-01

An alternative models framework was used to test three confirmatory factor analytic models for the Short Leyton Obsessional Inventory-Children's Version (Short LOI-CV) in a general population sample of 517 young adolescent twins (11-16 years). A one-factor model as implicit in current classification systems of Obsessive-Compulsive Disorder (OCD),…

A Longitudinal Motor Characterisation of the HdhQ111 Mouse Model of Huntington's Disease.

PubMed

Yhnell, Emma; Dunnett, Stephen B; Brooks, Simon P

2016-05-31

Huntington's disease (HD) is a rare, incurable neurodegenerative disorder caused by a CAG trinucleotide expansion with the first exon of the huntingtin gene. Numerous knock-in mouse models are currently available for modelling HD. However, before their use in scientific research, these models must be characterised to determine their face and predictive validity as models of the disease and their reliability in recapitulating HD symptoms. Manifest HD is currently diagnosed upon the onset of motor symptoms, thus we sought to longitudinally characterise the progression and severity of motor signs in the HdhQ111 knock-in mouse model of HD, in heterozygous mice. An extensive battery of motor tests including: rotarod, inverted lid test, balance beam, spontaneous locomotor activity and gait analysis were applied longitudinally to a cohort of HdhQ111 heterozygous mice in order to progressively assess motor function. A progressive failure to gain body weight was demonstrated from 11 months of age and motor problems in all measures of balance beam performance were shown in HdhQ111 heterozygous animals in comparison to wild type control animals from 9 months of age. A decreased latency to fall from the rotarod was demonstrated in HdhQ111 heterozygous animals in comparison to wild type animals, although this was not progressive with time. No genotype specific differences were demonstrated in any of the other motor tests included in the test battery. The HdhQ111 heterozygous mouse demonstrates a subtle and progressive motor phenotype that begins at 9 months of age. This mouse model represents an early disease stage and would be ideal for testing therapeutic strategies that require elongated lead-in times, such as viral gene therapies or striatal transplantation.

International Space Station ECLSS Technical Task Agreement Summary Report

NASA Technical Reports Server (NTRS)

Ray, C. D. (Compiler); Salyer, B. H. (Compiler)

1999-01-01

This Technical Memorandum provides a summary of current work accomplished under Technical Task Agreement (TTA) by the Marshall Space Flight Center (MSFC) regarding the International Space Station (ISS) Environmental Control and Life Support System (ECLSS). Current activities include ECLSS component design and development, computer model development, subsystem/integrated system testing, life testing, and general test support provided to the ISS program. Under ECLSS design, MSFC was responsible for the six major ECLSS functions, specifications and standard, component design and development, and was the architectural control agent for the ISS ECLSS. MSFC was responsible for ECLSS analytical model development. In-house subsystem and system level analysis and testing were conducted in support of the design process, including testing air revitalization, water reclamation and management hardware, and certain nonregenerative systems. The activities described herein were approved in task agreements between MSFC and NASA Headquarters Space Station Program Management Office and their prime contractor for the ISS, Boeing. These MSFC activities are in line to the designing, development, testing, and flight of ECLSS equipment planned by Boeing. MSFC's unique capabilities for performing integrated systems testing and analyses, and its ability to perform some tasks cheaper and faster to support ISS program needs, are the basis for the TTA activities.

Pictures and Words: Spanish and English Vocabulary in Classrooms

ERIC Educational Resources Information Center

Branum-Martin, Lee; Mehta, Paras D.; Francis, David J.; Foorman, Barbara R.; Cirino, Paul T.; Miller, Jon F.; Iglesias, Aquiles

2009-01-01

The current study evaluated the relation between Spanish and English vocabulary. Whereas previously reported correlations have revealed strong differences among types of vocabulary measures used and the ages of the students tested, no prior study had used a multilevel model to control for classroom-level differences. The current study used…

NREL and DONG Energy Collaboration for Grid Simulator Controls and Testing: Cooperative Research and Development Final Report, CRADA Number CRD-13-527

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gevorgian, Vahan

The National Renewable Energy Laboratory (NREL) and DONG Energy are interested in collaborating for the development of control algorithms, modeling, and grid simulator testing of wind turbine generator systems involving NWTC's advanced Controllable Grid Interface (CGI). NREL and DONG Energy will work together to develop control algorithms, models, test methods, and protocols involving NREL's CGI, as well as appropriate data acquisition systems for grid simulation testing. The CRADA also includes work on joint publication of results achieved from modeling and testing efforts. Further, DONG Energy will send staff to NREL on a long-term basis for collaborative work including modeling andmore » testing. NREL will send staff to DONG Energy on a short-term basis to visit wind power sites and participate in meetings relevant to this collaborative effort. DOE has provided NREL with over 10 years of support in developing custom facilities and capabilities to enable testing of full-scale integrated wind turbine drivetrain systems in accordance with the needs of the US wind industry. NREL currently operates a 2.5MW dynamometer and is in the processes of commissioning a 5MW dynamometer and a grid simulator (referred to as a 'Controllable Grid Interface' or CGI). DONG Energy is the market leader in offshore wind power development, with currently over 1 GW of on- and offshore wind power in operation, and 1.3 GW under construction. DONG Energy has on-going R&D projects involving high voltage DC (HVDC) transmission.« less

Augmented Method to Improve Thermal Data for the Figure Drift Thermal Distortion Predictions of the JWST OTIS Cryogenic Vacuum Test

NASA Technical Reports Server (NTRS)

Park, Sang C.; Carnahan, Timothy M.; Cohen, Lester M.; Congedo, Cherie B.; Eisenhower, Michael J.; Ousley, Wes; Weaver, Andrew; Yang, Kan

2017-01-01

The JWST Optical Telescope Element (OTE) assembly is the largest optically stable infrared-optimized telescope currently being manufactured and assembled, and is scheduled for launch in 2018. The JWST OTE, including the 18 segment primary mirror, secondary mirror, and the Aft Optics Subsystem (AOS) are designed to be passively cooled and operate near 45K. These optical elements are supported by a complex composite backplane structure. As a part of the structural distortion model validation efforts, a series of tests are planned during the cryogenic vacuum test of the fully integrated flight hardware at NASA JSC Chamber A. The successful ends to the thermal-distortion phases are heavily dependent on the accurate temperature knowledge of the OTE structural members. However, the current temperature sensor allocations during the cryo-vac test may not have sufficient fidelity to provide accurate knowledge of the temperature distributions within the composite structure. A method based on an inverse distance relationship among the sensors and thermal model nodes was developed to improve the thermal data provided for the nanometer scale WaveFront Error (WFE) predictions. The Linear Distance Weighted Interpolation (LDWI) method was developed to augment the thermal model predictions based on the sparse sensor information. This paper will encompass the development of the LDWI method using the test data from the earlier pathfinder cryo-vac tests, and the results of the notional and as tested WFE predictions from the structural finite element model cases to characterize the accuracies of this LDWI method.

Parameter estimation with Sandage-Loeb test

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geng, Jia-Jia; Zhang, Jing-Fei; Zhang, Xin, E-mail: gengjiajia163@163.com, E-mail: jfzhang@mail.neu.edu.cn, E-mail: zhangxin@mail.neu.edu.cn

2014-12-01

The Sandage-Loeb (SL) test directly measures the expansion rate of the universe in the redshift range of 2 ∼< z ∼< 5 by detecting redshift drift in the spectra of Lyman-α forest of distant quasars. We discuss the impact of the future SL test data on parameter estimation for the ΛCDM, the wCDM, and the w{sub 0}w{sub a}CDM models. To avoid the potential inconsistency with other observational data, we take the best-fitting dark energy model constrained by the current observations as the fiducial model to produce 30 mock SL test data. The SL test data provide an important supplement to the other dark energymore » probes, since they are extremely helpful in breaking the existing parameter degeneracies. We show that the strong degeneracy between Ω{sub m} and H{sub 0} in all the three dark energy models is well broken by the SL test. Compared to the current combined data of type Ia supernovae, baryon acoustic oscillation, cosmic microwave background, and Hubble constant, the 30-yr observation of SL test could improve the constraints on Ω{sub m} and H{sub 0} by more than 60% for all the three models. But the SL test can only moderately improve the constraint on the equation of state of dark energy. We show that a 30-yr observation of SL test could help improve the constraint on constant w by about 25%, and improve the constraints on w{sub 0} and w{sub a} by about 20% and 15%, respectively. We also quantify the constraining power of the SL test in the future high-precision joint geometric constraints on dark energy. The mock future supernova and baryon acoustic oscillation data are simulated based on the space-based project JDEM. We find that the 30-yr observation of SL test would help improve the measurement precision of Ω{sub m}, H{sub 0}, and w{sub a} by more than 70%, 20%, and 60%, respectively, for the w{sub 0}w{sub a}CDM model.« less

Modular Cognitive Behavioral Therapy for Youth Anxiety Disorders: A Partial Effectiveness Test in Schools

ERIC Educational Resources Information Center

Chiu, Angela Wai Mon

2010-01-01

The current study used a programmatic dissemination model as a guiding framework for testing an evidence-supported treatment (EST) for child anxiety disorders in the school setting. The main goal of the project was to conduct the first of a planned series of partial-effectiveness tests (group-design randomized controlled trials) evaluating the…

75 FR 8479 - Airworthiness Directives; Airbus Model A340-541 and -642 Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-25

... A340-600 full scale fatigue test, cracks were found on left and right sides of the rear spar vertical... scale fatigue test, cracks were found on left and right sides of the rear spar vertical cruciform at... this full scale fatigue test completion, it has been determined that the current inspections values...

Alternative Statistical Frameworks for Student Growth Percentile Estimation

ERIC Educational Resources Information Center

Lockwood, J. R.; Castellano, Katherine E.

2015-01-01

This article suggests two alternative statistical approaches for estimating student growth percentiles (SGP). The first is to estimate percentile ranks of current test scores conditional on past test scores directly, by modeling the conditional cumulative distribution functions, rather than indirectly through quantile regressions. This would…

So Many Chemicals, So Little Time... Evolution of Computational Toxicology (NCSU Toxicology Lecture Series)

EPA Science Inventory

Current testing is limited by traditional testing models and regulatory systems. An overview is given of high throughput screening approaches to provide broader chemical and biological coverage, toxicokinetics and molecular pathway data and tools to facilitate utilization for reg...

NASA Occupant Protection Standards Development

NASA Technical Reports Server (NTRS)

Somers, Jeffrey; Gernhardt, Michael; Lawrence, Charles

2012-01-01

Historically, spacecraft landing systems have been tested with human volunteers, because analytical methods for estimating injury risk were insufficient. These tests were conducted with flight-like suits and seats to verify the safety of the landing systems. Currently, NASA uses the Brinkley Dynamic Response Index to estimate injury risk, although applying it to the NASA environment has drawbacks: (1) Does not indicate severity or anatomical location of injury (2) Unclear if model applies to NASA applications. Because of these limitations, a new validated, analytical approach was desired. Leveraging off of the current state of the art in automotive safety and racing, a new approach was developed. The approach has several aspects: (1) Define the acceptable level of injury risk by injury severity (2) Determine the appropriate human surrogate for testing and modeling (3) Mine existing human injury data to determine appropriate Injury Assessment Reference Values (IARV). (4) Rigorously Validate the IARVs with sub-injurious human testing (5) Use validated IARVs to update standards and vehicle requirement

Analytical modeling and analysis of magnetic field and torque for novel axial flux eddy current couplers with PM excitation

NASA Astrophysics Data System (ADS)

Li, Zhao; Wang, Dazhi; Zheng, Di; Yu, Linxin

2017-10-01

Rotational permanent magnet eddy current couplers are promising devices for torque and speed transmission without any mechanical contact. In this study, flux-concentration disk-type permanent magnet eddy current couplers with double conductor rotor are investigated. Given the drawback of the accurate three-dimensional finite element method, this paper proposes a mixed two-dimensional analytical modeling approach. Based on this approach, the closed-form expressions of magnetic field, eddy current, electromagnetic force and torque for such devices are obtained. Finally, a three-dimensional finite element method is employed to validate the analytical results. Besides, a prototype is manufactured and tested for the torque-speed characteristic.

Thermal Testing of Ablators in the NASA Johnson Space Center Radiant Heat Test Facility

NASA Technical Reports Server (NTRS)

Del Papa, Steven; Milhoan, Jim; Remark, Brian; Suess, Leonard

2016-01-01

A spacecraft's thermal protection system (TPS) is required to survive the harsh environment experienced during reentry. Accurate thermal modeling of the TPS is required to since uncertainties in the thermal response result in higher design margins and an increase in mass. The Radiant Heat Test Facility (RHTF) located at the NASA Johnson Space Center (JSC) replicates the reentry temperatures and pressures on system level full scale TPS test models for the validation of thermal math models. Reusable TPS, i.e. tile or reinforced carbon-carbon (RCC), have been the primary materials tested in the past. However, current capsule designs for MPCV and commercial programs have required the use of an ablator TPS. The RHTF has successfully completed a pathfinder program on avcoat ablator material to demonstrate the feasibility of ablator testing. The test results and corresponding ablation analysis results are presented in this paper.

Large transient fault current test of an electrical roll ring

NASA Technical Reports Server (NTRS)

Yenni, Edward J.; Birchenough, Arthur G.

1992-01-01

The space station uses precision rotary gimbals to provide for sun tracking of its photoelectric arrays. Electrical power, command signals and data are transferred across the gimbals by roll rings. Roll rings have been shown to be capable of highly efficient electrical transmission and long life, through tests conducted at the NASA Lewis Research Center and Honeywell's Satellite and Space Systems Division in Phoenix, AZ. Large potential fault currents inherent to the power system's DC distribution architecture, have brought about the need to evaluate the effects of large transient fault currents on roll rings. A test recently conducted at Lewis subjected a roll ring to a simulated worst case space station electrical fault. The system model used to obtain the fault profile is described, along with details of the reduced order circuit that was used to simulate the fault. Test results comparing roll ring performance before and after the fault are also presented.

Applying the cell-based coagulation model in the management of critical bleeding.

PubMed

Ho, K M; Pavey, W

2017-03-01

The cell-based coagulation model was proposed 15 years ago, yet has not been applied commonly in the management of critical bleeding. Nevertheless, this alternative model may better explain the physiological basis of current coagulation management during critical bleeding. In this article we describe the limitations of the traditional coagulation protein cascade and standard coagulation tests, and explain the potential advantages of applying the cell-based model in current coagulation management strategies. The cell-based coagulation model builds on the traditional coagulation model and explains many recent clinical observations and research findings related to critical bleeding unexplained by the traditional model, including the encouraging results of using empirical 1:1:1 fresh frozen plasma:platelets:red blood cells transfusion strategy, and the use of viscoelastic and platelet function tests in patients with critical bleeding. From a practical perspective, applying the cell-based coagulation model also explains why new direct oral anticoagulants are effective systemic anticoagulants even without affecting activated partial thromboplastin time or the International Normalized Ratio in a dose-related fashion. The cell-based coagulation model represents the most cohesive scientific framework on which we can understand and manage coagulation during critical bleeding.

Net current control device. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fugate, D.; Cooper, J.H.

1998-11-01

Net currents generally result in elevated magnetic fields because the alternate paths are distant from the circuit conductors. Investigations have shown that one of the primary sources of power frequency magnetic fields in residential buildings is currents that return to their source via paths other than the neutral conductors. As part of EPRI`s Magnetic Field Shielding Project, ferromagnetic devices, called net current control (NCC) devices, were developed and tested for use in reducing net currents on electric power cables and the resulting magnetic fields. Applied to a residential service drop, an NCC device reduces net current by forcing current offmore » local non-utility ground paths, and back onto the neutral conductor. Circuit models and basic design equations for the NCC concept were developed, and proof-of-principles tests were carried out on an actual residence with cooperation from the local utility. After proving the basic concepts, three prototype NCC devices were built and tested on a simulated neighborhood power system. Additional prototypes were built for testing by interested EPRI utility members. Results have shown that the NCC prototypes installed on residential service drops reduce net currents to milliampere levels with compromising the safety of the ground system. Although the focus was on application to residential service cables, the NCC concept is applicable to single-phase and three-phase distribution systems as well.« less

Mapping patient pathways and estimating resource use for point of care versus standard testing and treatment of chlamydia and gonorrhoea in genitourinary medicine clinics in the UK.

PubMed

Adams, Elisabeth J; Ehrlich, Alice; Turner, Katherine M E; Shah, Kunj; Macleod, John; Goldenberg, Simon; Meray, Robin K; Pearce, Vikki; Horner, Patrick

2014-07-23

We aimed to explore patient pathways using a chlamydia/gonorrhoea point-of-care (POC) nucleic acid amplification test (NAAT), and estimate and compare the costs of the proposed POC pathways with the current pathways using standard laboratory-based NAAT testing. Workshops were conducted with healthcare professionals at four sexual health clinics representing diverse models of care in the UK. They mapped out current pathways that used chlamydia/gonorrhoea tests, and constructed new pathways using a POC NAAT. Healthcare professionals' time was assessed in each pathway. The proposed POC pathways were then priced using a model built in Microsoft Excel, and compared to previously published costs for pathways using standard NAAT-based testing in an off-site laboratory. Pathways using a POC NAAT for asymptomatic and symptomatic patients and chlamydia/gonorrhoea-only tests were shorter and less expensive than most of the current pathways. Notably, we estimate that POC testing as part of a sexual health screen for symptomatic patients, or as stand-alone chlamydia/gonorrhoea testing, could reduce costs per patient by as much as £16 or £6, respectively. In both cases, healthcare professionals' time would be reduced by approximately 10 min per patient. POC testing for chlamydia/gonorrhoea in a clinical setting may reduce costs and clinician time, and may lead to more appropriate and quicker care for patients. Further study is warranted on how to best implement POC testing in clinics, and on the broader clinical and cost implications of this technology. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Model invariance across genders of the Broad Autism Phenotype Questionnaire.

PubMed

Broderick, Neill; Wade, Jordan L; Meyer, J Patrick; Hull, Michael; Reeve, Ronald E

2015-10-01

ASD is one of the most heritable neuropsychiatric disorders, though comprehensive genetic liability remains elusive. To facilitate genetic research, researchers employ the concept of the broad autism phenotype (BAP), a milder presentation of traits in undiagnosed relatives. Research suggests that the BAP Questionnaire (BAPQ) demonstrates psychometric properties superior to other self-report measures. To examine evidence regarding validity of the BAPQ, the current study used confirmatory factor analysis to test the assumption of model invariance across genders. Results of the current study upheld model invariance at each level of parameter constraint; however, model fit indices suggested limited goodness-of-fit between the proposed model and the sample. Exploratory analyses investigated alternate factor structure models but ultimately supported the proposed three-factor structure model.

Eddy Current Damper for Cryogenic Applications

NASA Astrophysics Data System (ADS)

Starin, Scott; Crosno, Fred

2002-09-01

This presentation considers the following topics: the need for cryogenic energy absorption, high speed damper characteristics, gearbox characteristics, composite assembly characteristics, performance tests, simulation models.

Report on International Collaboration Involving the FE Heater and HG-A Tests at Mont Terri

DOE Office of Scientific and Technical Information (OSTI.GOV)

Houseworth, Jim; Rutqvist, Jonny; Asahina, Daisuke

Nuclear waste programs outside of the US have focused on different host rock types for geological disposal of high-level radioactive waste. Several countries, including France, Switzerland, Belgium, and Japan are exploring the possibility of waste disposal in shale and other clay-rich rock that fall within the general classification of argillaceous rock. This rock type is also of interest for the US program because the US has extensive sedimentary basins containing large deposits of argillaceous rock. LBNL, as part of the DOE-NE Used Fuel Disposition Campaign, is collaborating on some of the underground research laboratory (URL) activities at the Mont Terrimore » URL near Saint-Ursanne, Switzerland. The Mont Terri project, which began in 1995, has developed a URL at a depth of about 300 m in a stiff clay formation called the Opalinus Clay. Our current collaboration efforts include two test modeling activities for the FE heater test and the HG-A leak-off test. This report documents results concerning our current modeling of these field tests. The overall objectives of these activities include an improved understanding of and advanced relevant modeling capabilities for EDZ evolution in clay repositories and the associated coupled processes, and to develop a technical basis for the maximum allowable temperature for a clay repository.« less

University of Washington/ Northwest National Marine Renewable Energy Center Tidal Current Technology Test Protocol, Instrumentation, Design Code, and Oceanographic Modeling Collaboration: Cooperative Research and Development Final Report, CRADA Number CRD-11-452

DOE Office of Scientific and Technical Information (OSTI.GOV)

Driscoll, Frederick R.

The University of Washington (UW) - Northwest National Marine Renewable Energy Center (UW-NNMREC) and the National Renewable Energy Laboratory (NREL) will collaborate to advance research and development (R&D) of Marine Hydrokinetic (MHK) renewable energy technology, specifically renewable energy captured from ocean tidal currents. UW-NNMREC is endeavoring to establish infrastructure, capabilities and tools to support in-water testing of marine energy technology. NREL is leveraging its experience and capabilities in field testing of wind systems to develop protocols and instrumentation to advance field testing of MHK systems. Under this work, UW-NNMREC and NREL will work together to develop a common instrumentation systemmore » and testing methodologies, standards and protocols. UW-NNMREC is also establishing simulation capabilities for MHK turbine and turbine arrays. NREL has extensive experience in wind turbine array modeling and is developing several computer based numerical simulation capabilities for MHK systems. Under this CRADA, UW-NNMREC and NREL will work together to augment single device and array modeling codes. As part of this effort UW NNMREC will also work with NREL to run simulations on NREL's high performance computer system.« less

Final Report - IHLW PCT, Spinel T1%, Electrical Conductivity, and Viscosity Model Development, VSL-07R1240-4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kruger, Albert A.; Piepel, Gregory F.; Landmesser, S. M.

2013-11-13

This report is the last in a series of currently scheduled reports that presents the results from the High Level Waste (HLW) glass formulation development and testing work performed at the Vitreous State Laboratory (VSL) of the Catholic University of America (CUA) and the development of IHLW property-composition models performed jointly by Pacific Northwest National Laboratory (PNNL) and VSL for the River Protection Project-Waste Treatment and Immobilization Plant (RPP-WTP). Specifically, this report presents results of glass testing at VSL and model development at PNNL for Product Consistency Test (PCT), one-percent crystal fraction temperature (T1%), electrical conductivity (EC), and viscosity ofmore » HLW glasses. The models presented in this report may be augmented and additional validation work performed during any future immobilized HLW (IHLW) model development work. Completion of the test objectives is addressed.« less

Three-Dimensional Finite-Element Simulation for a Thermoelectric Generator Module

NASA Astrophysics Data System (ADS)

Hu, Xiaokai; Takazawa, Hiroyuki; Nagase, Kazuo; Ohta, Michihiro; Yamamoto, Atsushi

2015-10-01

A three-dimensional closed-circuit numerical model of a thermoelectric generator (TEG) module has been constructed with COMSOL® Multiphysics to verify a module test system. The Seebeck, Peltier, and Thomson effects and Joule heating are included in the thermoelectric conversion model. The TEG model is employed to simulate the operation of a 16-leg TEG module based on bismuth telluride with temperature-dependent material properties. The module is mounted on a test platform, and simulated by combining the heat conduction process and thermoelectric conversion process. Simulation results are obtained for the terminal voltage, output power, heat flow, and efficiency as functions of the electric current; the results are compared with measurement data. The Joule and Thomson heats in all the thermoelectric legs, as functions of the electric current, are calculated by finite-element volume integration over the entire legs. The Peltier heat being pumped at the hot side and released at the cold side of the module are also presented in relation to the electric current. The energy balance relations between heat and electricity are verified to support the simulation.

Second Generation Crop Yield Models Review

NASA Technical Reports Server (NTRS)

Hodges, T. (Principal Investigator)

1982-01-01

Second generation yield models, including crop growth simulation models and plant process models, may be suitable for large area crop yield forecasting in the yield model development project. Subjective and objective criteria for model selection are defined and models which might be selected are reviewed. Models may be selected to provide submodels as input to other models; for further development and testing; or for immediate testing as forecasting tools. A plant process model may range in complexity from several dozen submodels simulating (1) energy, carbohydrates, and minerals; (2) change in biomass of various organs; and (3) initiation and development of plant organs, to a few submodels simulating key physiological processes. The most complex models cannot be used directly in large area forecasting but may provide submodels which can be simplified for inclusion into simpler plant process models. Both published and unpublished models which may be used for development or testing are reviewed. Several other models, currently under development, may become available at a later date.

Curved-flow, rolling-flow, and oscillatory pure-yawing wind-tunnel test methods for determination of dynamic stability derivatives

NASA Technical Reports Server (NTRS)

Chambers, J. R.; Grafton, S. B.; Lutze, F. H.

1981-01-01

Dynamic stability derivatives are evaluated on the basis of rolling-flow, curved-flow and snaking tests. Attention is given to the hardware associated with curved-flow, rolling-flow and oscillatory pure-yawing wind-tunnel tests. It is found that the snaking technique, when combined with linear- and forced-oscillation methods, yields an important method for evaluating beta derivatives for current configurations at high angles of attack. Since the rolling flow model is fixed during testing, forced oscillations may be imparted to the model, permitting the measurement of damping and cross-derivatives. These results, when coupled with basic rolling-flow or rotary-balance data, yield a highly accurate mathematical model for studies of incipient spin and spin entry.

Improve SSME power balance model

NASA Technical Reports Server (NTRS)

Karr, Gerald R.

1992-01-01

Effort was dedicated to development and testing of a formal strategy for reconciling uncertain test data with physically limited computational prediction. Specific weaknesses in the logical structure of the current Power Balance Model (PBM) version are described with emphasis given to the main routing subroutines BAL and DATRED. Selected results from a variational analysis of PBM predictions are compared to Technology Test Bed (TTB) variational study results to assess PBM predictive capability. The motivation for systematic integration of uncertain test data with computational predictions based on limited physical models is provided. The theoretical foundation for the reconciliation strategy developed in this effort is presented, and results of a reconciliation analysis of the Space Shuttle Main Engine (SSME) high pressure fuel side turbopump subsystem are examined.

On-Line, Self-Learning, Predictive Tool for Determining Payload Thermal Response

NASA Technical Reports Server (NTRS)

Jen, Chian-Li; Tilwick, Leon

2000-01-01

This paper will present the results of a joint ManTech / Goddard R&D effort, currently under way, to develop and test a computer based, on-line, predictive simulation model for use by facility operators to predict the thermal response of a payload during thermal vacuum testing. Thermal response was identified as an area that could benefit from the algorithms developed by Dr. Jeri for complex computer simulations. Most thermal vacuum test setups are unique since no two payloads have the same thermal properties. This requires that the operators depend on their past experiences to conduct the test which requires time for them to learn how the payload responds while at the same time limiting any risk of exceeding hot or cold temperature limits. The predictive tool being developed is intended to be used with the new Thermal Vacuum Data System (TVDS) developed at Goddard for the Thermal Vacuum Test Operations group. This model can learn the thermal response of the payload by reading a few data points from the TVDS, accepting the payload's current temperature as the initial condition for prediction. The model can then be used as a predictive tool to estimate the future payload temperatures according to a predetermined shroud temperature profile. If the error of prediction is too big, the model can be asked to re-learn the new situation on-line in real-time and give a new prediction. Based on some preliminary tests, we feel this predictive model can forecast the payload temperature of the entire test cycle within 5 degrees Celsius after it has learned 3 times during the beginning of the test. The tool will allow the operator to play "what-if' experiments to decide what is his best shroud temperature set-point control strategy. This tool will save money by minimizing guess work and optimizing transitions as well as making the testing process safer and easier to conduct.

Outputs as Educator Effectiveness in the United States: Shifting towards Political Accountability

ERIC Educational Resources Information Center

Piro, Jody S.; Mullen, Laurie

2013-01-01

The definition of educator effectiveness is being redefined by econometric modeling to evidence student achievement on standardized tests. While the reasons that econometric frameworks are in vogue are many, it is clear that the strength of such models lie in the quantifiable evidence of student learning. Current accountability models frame…

A description of STEMS-- the stand and tree evaluation and modeling system.

Treesearch

David M. Belcher; Margaret R. Holdaway; Gary J. Brand

1982-01-01

This paper describes STEMS (Stand and Tree Evaluation and Modeling System), the current computerized Lake State tree growth projection system. It presents the program structure, discusses the growth and mortality components, the management subsystem, and the regeneration subsystem. Some preliminary results of model testing are presented and an application is...

A Transactional Model of Bullying and Victimization

ERIC Educational Resources Information Center

Georgiou, Stelios N.; Fanti, Kostas A.

2010-01-01

The purpose of the current study was to develop and test a transactional model, based on longitudinal data, capable to describe the existing interrelation between maternal behavior and child bullying and victimization experiences over time. The results confirmed the existence of such a model for bullying, but not for victimization in terms of…

The Relationship between Reciprocity and the Emotional and Behavioural Responses of Staff

ERIC Educational Resources Information Center

Thomas, Cathryn; Rose, John

2010-01-01

Background: The current study examines a model relating to the concept of reciprocity and burnout in staff, incorporating previous research findings based upon Weiner's (1980, 1986) cognitive-emotional model linking emotions, optimism and helping behaviour, with the aim of testing the model. Materials: Staff working in community homes within the…

Proportional Reasoning of Preservice Elementary Education Majors: An Epistemic Model of the Proportional Reasoning Construct.

ERIC Educational Resources Information Center

Fleener, M. Jayne

Current research and learning theory suggest that a hierarchy of proportional reasoning exists that can be tested. Using G. Vergnaud's four complexity variables (structure, content, numerical characteristics, and presentation) and T. E. Kieren's model of rational number knowledge building, an epistemic model of proportional reasoning was…

Flooding Experiments and Modeling for Improved Reactor Safety

DOE Office of Scientific and Technical Information (OSTI.GOV)

Solmos, M.; Hogan, K. J.; Vierow, K.

2008-09-14

Countercurrent two-phase flow and “flooding” phenomena in light water reactor systems are being investigated experimentally and analytically to improve reactor safety of current and future reactors. The aspects that will be better clarified are the effects of condensation and tube inclination on flooding in large diameter tubes. The current project aims to improve the level of understanding of flooding mechanisms and to develop an analysis model for more accurate evaluations of flooding in the pressurizer surge line of a Pressurized Water Reactor (PWR). Interest in flooding has recently increased because Countercurrent Flow Limitation (CCFL) in the AP600 pressurizer surge linemore » can affect the vessel refill rate following a small break LOCA and because analysis of hypothetical severe accidents with the current flooding models in reactor safety codes shows that these models represent the largest uncertainty in analysis of steam generator tube creep rupture. During a hypothetical station blackout without auxiliary feedwater recovery, should the hot leg become voided, the pressurizer liquid will drain to the hot leg and flooding may occur in the surge line. The flooding model heavily influences the pressurizer emptying rate and the potential for surge line structural failure due to overheating and creep rupture. The air-water test results in vertical tubes are presented in this paper along with a semi-empirical correlation for the onset of flooding. The unique aspects of the study include careful experimentation on large-diameter tubes and an integrated program in which air-water testing provides benchmark knowledge and visualization data from which to conduct steam-water testing.« less

Dynamic Modeling, Controls, and Testing for Electrified Aircraft

NASA Technical Reports Server (NTRS)

Connolly, Joseph; Stalcup, Erik

2017-01-01

Electrified aircraft have the potential to provide significant benefits for efficiency and emissions reductions. To assess these potential benefits, modeling tools are needed to provide rapid evaluation of diverse concepts and to ensure safe operability and peak performance over the mission. The modeling challenge for these vehicles is the ability to show significant benefits over the current highly refined aircraft systems. The STARC-ABL (single-aisle turbo-electric aircraft with an aft boundary layer propulsor) is a new test proposal that builds upon previous N3-X team hybrid designs. This presentation describes the STARC-ABL concept, the NASA Electric Aircraft Testbed (NEAT) which will allow testing of the STARC-ABL powertrain, and the related modeling and simulation efforts to date. Modeling and simulation includes a turbofan simulation, Numeric Propulsion System Simulation (NPSS), which has been integrated with NEAT; and a power systems and control model for predicting testbed performance and evaluating control schemes. Model predictions provide good comparisons with testbed data for an NPSS-integrated test of the single-string configuration of NEAT.

An experimental test of the 'transmission-line model' of electromagnetic radiation from triggered lightning return strokes

NASA Technical Reports Server (NTRS)

Willett, J. C.; Idone, V. P.; Orville, R. E.; Leteinturier, C.; Eybert-Berard, A.

1988-01-01

Peak currents, two-dimensional average propagation speeds, and electric field waveforms for a number of subsequent return strikes in rocket-triggered lightning flashes were measured in order to test the 'transmission-line model' of return-stroke radiation of Uman and McLain (1970). Reasonable agreement is found between the propagation speeds measured with the streak camera and those deduced from the transmission-line model. A modification of the model is proposed in which two wave fronts travel upward and downward away from a junction point a short distance above the ground.

Computer modeling of heat pipe performance

NASA Technical Reports Server (NTRS)

Peterson, G. P.

1983-01-01

A parametric study of the defining equations which govern the steady state operational characteristics of the Grumman monogroove dual passage heat pipe is presented. These defining equations are combined to develop a mathematical model which describes and predicts the operational and performance capabilities of a specific heat pipe given the necessary physical characteristics and working fluid. Included is a brief review of the current literature, a discussion of the governing equations, and a description of both the mathematical and computer model. Final results of preliminary test runs of the model are presented and compared with experimental tests on actual prototypes.

An experimental test of the 'transmission-line model' of electromagnetic radiation from triggered lightning return strokes

NASA Astrophysics Data System (ADS)

Willett, J. C.; Idone, V. P.; Orville, R. E.; Leteinturier, C.; Eybert-Berard, A.

1988-04-01

Peak currents, two-dimensional average propagation speeds, and electric field waveforms for a number of subsequent return strikes in rocket-triggered lightning flashes were measured in order to test the 'transmission-line model' of return-stroke radiation of Uman and McLain (1970). Reasonable agreement is found between the propagation speeds measured with the streak camera and those deduced from the transmission-line model. A modification of the model is proposed in which two wave fronts travel upward and downward away from a junction point a short distance above the ground.

sFlt-1/PlGF ratio test for pre-eclampsia: an economic assessment for the UK.

PubMed

Vatish, M; Strunz-McKendry, T; Hund, M; Allegranza, D; Wolf, C; Smare, C

2016-12-01

To assess the economic impact of introducing into clinical practice in the UK the soluble fms-like tyrosine kinase (sFlt-1) to placental growth factor (PlGF) ratio test for guiding the management of pre-eclampsia. We used an economic model estimating the incremental value of information, from a UK National Health Service payer's perspective, generated by the sFlt-1/PlGF ratio test, compared with current diagnostic procedures, in guiding the management of women with suspected pre-eclampsia. The economic model estimated costs associated with the diagnosis and management of pre-eclampsia in pregnant women between 24 + 0 and 36 + 6 weeks' gestation, managed in either a 'test' scenario in which the sFlt-1/PlGF test is used in addition to current diagnostic procedures, or a 'no-test' scenario in which clinical decisions are based on current diagnostic procedures alone. Test characteristics and resource use were derived from PROGNOSIS, a non-interventional study in women presenting with clinical suspicion of pre-eclampsia. The main outcome measure from the economic model was the cost per patient per episode of care, from first suspicion of pre-eclampsia to birth. Introduction of the sFlt-1/PlGF ratio test into clinical practice is expected to result in cost savings of £344 per patient compared with a no-test scenario. Savings are generated primarily through an improvement in diagnostic accuracy and subsequent reduction in unnecessary hospitalization. Introducing the sFlt-1/PlGF ratio test into clinical practice in the UK was shown to be cost-saving by reducing unnecessary hospitalization of women at low risk of developing pre-eclampsia. In addition, the test ensures that those women at higher risk are identified and managed appropriately. © 2016 Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology. © 2016 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Validation of finite element model of transcranial electrical stimulation using scalp potentials: implications for clinical dose

NASA Astrophysics Data System (ADS)

Datta, Abhishek; Zhou, Xiang; Su, Yuzhou; Parra, Lucas C.; Bikson, Marom

2013-06-01

Objective. During transcranial electrical stimulation, current passage across the scalp generates voltage across the scalp surface. The goal was to characterize these scalp voltages for the purpose of validating subject-specific finite element method (FEM) models of current flow. Approach. Using a recording electrode array, we mapped skin voltages resulting from low-intensity transcranial electrical stimulation. These voltage recordings were used to compare the predictions obtained from the high-resolution model based on the subject undergoing transcranial stimulation. Main results. Each of the four stimulation electrode configurations tested resulted in a distinct distribution of scalp voltages; these spatial maps were linear with applied current amplitude (0.1 to 1 mA) over low frequencies (1 to 10 Hz). The FEM model accurately predicted the distinct voltage distributions and correlated the induced scalp voltages with current flow through cortex. Significance. Our results provide the first direct model validation for these subject-specific modeling approaches. In addition, the monitoring of scalp voltages may be used to verify electrode placement to increase transcranial electrical stimulation safety and reproducibility.

Reaction formulation for radiation and scattering from plates, corner reflectors and dielectric-coated cylinders

NASA Technical Reports Server (NTRS)

Wang, N. N.

1974-01-01

The reaction concept is employed to formulate an integral equation for radiation and scattering from plates, corner reflectors, and dielectric-coated conducting cylinders. The surface-current density on the conducting surface is expanded with subsectional bases. The dielectric layer is modeled with polarization currents radiating in free space. Maxwell's equation and the boundary conditions are employed to express the polarization-current distribution in terms of the surface-current density on the conducting surface. By enforcing reaction tests with an array of electric test sources, the moment method is employed to reduce the integral equation to a matrix equation. Inversion of the matrix equation yields the current distribution, and the scattered field is then obtained by integrating the current distribution. The theory, computer program and numerical results are presented for radiation and scattering from plates, corner reflectors, and dielectric-coated conducting cylinders.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Puskar, Joseph David; Quintana, Michael A.; Sorensen, Neil Robert

A program is underway at Sandia National Laboratories to predict long-term reliability of photovoltaic (PV) systems. The vehicle for the reliability predictions is a Reliability Block Diagram (RBD), which models system behavior. Because this model is based mainly on field failure and repair times, it can be used to predict current reliability, but it cannot currently be used to accurately predict lifetime. In order to be truly predictive, physics-informed degradation processes and failure mechanisms need to be included in the model. This paper describes accelerated life testing of metal foil tapes used in thin-film PV modules, and how tape jointmore » degradation, a possible failure mode, can be incorporated into the model.« less

Measurement Requirements for Improved Modeling of Arcjet Facility Flows

NASA Technical Reports Server (NTRS)

Fletcher, Douglas G.

2000-01-01

Current efforts to develop new reusable launch vehicles and to pursue low-cost robotic planetary missions have led to a renewed interest in understanding arc-jet flows. Part of this renewed interest is concerned with improving the understanding of arc-jet test results and the potential use of available computational-fluid- dynamic (CFD) codes to aid in this effort. These CFD codes have been extensively developed and tested for application to nonequilibrium, hypersonic flow modeling. It is envisioned, perhaps naively, that the application of these CFD codes to the simulation of arc-jet flows would serve two purposes: first. the codes would help to characterize the nonequilibrium nature of the arc-jet flows; and second. arc-jet experiments could potentially be used to validate the flow models. These two objectives are, to some extent, mutually exclusive. However, the purpose of the present discussion is to address what role CFD codes can play in the current arc-jet flow characterization effort, and whether or not the simulation of arc-jet facility tests can be used to eva1uate some of the modeling that is used to formu1ate these codes. This presentation is organized into several sections. In the introductory section, the development of large-scale, constricted-arc test facilities within NASA is reviewed, and the current state of flow diagnostics using conventional instrumentation is summarized. The motivation for using CFD to simulate arc-jet flows is addressed in the next section, and the basic requirements for CFD models that would be used for these simulations are briefly discussed. This section is followed by a more detailed description of experimental measurements that are needed to initiate credible simulations and to evaluate their fidelity in the different flow regions of an arc-jet facility. Observations from a recent combined computational and experiment.al investigation of shock-layer flows in a large-scale arc-jet facility are then used to illustrate the current state of development of diagnostic instrumentation, CFD simulations, and general knowledge in the field of arc-jet characterization. Finally, the main points are summarized and recommendations for future efforts are given.

Experimental Investigation of a Hall-Current Accelerator. M.S. Thesis

NASA Technical Reports Server (NTRS)

Plank, G. M.

1983-01-01

The Hall-current accelerator is being investigated for use in the 1000-2000 sec. range of specific impulse. Three models of this thruster were tested. The first two models had three permanent magnets to supply the magnetic field and the third model had six magnets to supply the field. The third model thus had approximately twice the magnetic field of the first two. The first and second models differ only in the shape of the magnetic field. All other factors remained the same for the three models except for the anode-cathode distance, which was changed to allow for the three thrusters to have the same magnetic field integral between the anode and the cathode. These Hall thrusters were tested to determine the plasma properties, the beam characteristics, and the thruster characteristics. The thruster operated in three modes: (1) main cathode only, (2) main cathode with neutralizer cathode, and (3) neutralizer cathode only. The plasma properties were measured along an axial line, 1 mm inside the cathode radius, at a distance of 0.2 to 6.2 cm from the anode. Results show that the current used to heat the cathode produced nonuniformities in the magnetic field, hence also in the plasma properties. In a Hall thruster this general design appears to provide the most thrust when operated at a magnetic field less than the maximum value studied.

The trials and tribulations of a practitioner-researcher: challenges and lessons learned through testing a feminist-cognitive-relational social work model of practice.

PubMed

Dombo, Eileen A; Bass, Ami P

2014-01-01

In practice with adult women who survived childhood sexual abuse, the field of social work currently lacks an evidence-based intervention. The current interventions, from the 1990s, come primarily from psychologists. The hypothesis that the Feminist-Cognitive-Relational Social Work Model and Intervention will be more effective in decreasing cognitive distortions, and increasing intimacy and relational health when compared to the standard agency intervention was tested in a quasi-experimental study. The challenges in carrying out the study in small, non-profit organizations are explored to highlight the difficulties in developing evidence-based interventions. Changes to implementation that resulted from the research findings are discussed.

A Review of the Application of Body-on-a-Chip for Drug Test and Its Latest Trend of Incorporating Barrier Tissue.

PubMed

Jin, Haoyi; Yu, Yanqiu

2016-10-01

High-quality preclinical bioassay models are essential for drug research and development. We reviewed the emerging body-on-a-chip technology, which serves as a promising model to overcome the limitations of traditional bioassay models, and introduced existing models of body-on-a-chip, their constitutional details, application for drug testing, and individual features of these models. We put special emphasis on the latest trend in this field of incorporating barrier tissue into body-on-a-chip and discussed several remaining challenges of current body-on-a-chip. © 2015 Society for Laboratory Automation and Screening.

Single-arm phase II trial design under parametric cure models.

PubMed

Wu, Jianrong

2015-01-01

The current practice of designing single-arm phase II survival trials is limited under the exponential model. Trial design under the exponential model may not be appropriate when a portion of patients are cured. There is no literature available for designing single-arm phase II trials under the parametric cure model. In this paper, a test statistic is proposed, and a sample size formula is derived for designing single-arm phase II trials under a class of parametric cure models. Extensive simulations showed that the proposed test and sample size formula perform very well under different scenarios. Copyright © 2015 John Wiley & Sons, Ltd.

Modeling the superstorm in November 2003

NASA Astrophysics Data System (ADS)

Fok, Mei-Ching; Moore, Thomas E.; Slinker, Steve P.; Fedder, Joel A.; Delcourt, Dominique C.; Nosé, Masahito; Chen, Sheng-Hsien

2011-01-01

The superstorm on 20-21 November 2003 was the largest geomagnetic storm in solar cycle 23 as measured by Dst, which attained a minimum value of -422 nT. We have simulated this storm to understand how particles originating from the solar wind and ionosphere get access to the magnetosphere and how the subsequent transport and energization processes contribute to the buildup of the ring current. The global electromagnetic configuration and the solar wind H+ distribution are specified by the Lyon-Fedder-Mobarry (LFM) magnetohydrodynamics model. The outflow of H+ and O+ ions from the ionosphere are also considered. Their trajectories in the magnetosphere are followed by a test-particle code. The particle distributions at the inner plasma sheet established by the LFM model and test-particle calculations are then used as boundary conditions for a ring current model. Our simulations reproduce the rapid decrease of Dst during the storm main phase and the fast initial phase of recovery. Shielding in the inner magnetosphere is established at early main phase. This shielding field lasts several hours and then breaks down at late main phase. At the peak of the storm, strong penetration of ions earthward to L shell of 1.5 is revealed in the simulation. It is surprising that O+ is significant but not the dominant species in the ring current in our calculation for this major storm. It is very likely that substorm effects are not well represented in the models and O+ energization is underestimated. Ring current simulation with O+ energy density at the boundary set comparable to Geotail observations produces excellent agreement with the observed symH. As expected in superstorms, ring current O+ is the dominant species over H+ during the main to midrecovery phase of the storm.

Practical Formal Verification of Diagnosability of Large Models via Symbolic Model Checking

NASA Technical Reports Server (NTRS)

Cavada, Roberto; Pecheur, Charles

2003-01-01

This document reports on the activities carried out during a four-week visit of Roberto Cavada at the NASA Ames Research Center. The main goal was to test the practical applicability of the framework proposed, where a diagnosability problem is reduced to a Symbolic Model Checking problem. Section 2 contains a brief explanation of major techniques currently used in Symbolic Model Checking, and how these techniques can be tuned in order to obtain good performances when using Model Checking tools. Diagnosability is performed on large and structured models of real plants. Section 3 describes how these plants are modeled, and how models can be simplified to improve the performance of Symbolic Model Checkers. Section 4 reports scalability results. Three test cases are briefly presented, and several parameters and techniques have been applied on those test cases in order to produce comparison tables. Furthermore, comparison between several Model Checkers is reported. Section 5 summarizes the application of diagnosability verification to a real application. Several properties have been tested, and results have been highlighted. Finally, section 6 draws some conclusions, and outlines future lines of research.

In Vitro Microfluidic Models for Neurodegenerative Disorders.

PubMed

Osaki, Tatsuya; Shin, Yoojin; Sivathanu, Vivek; Campisi, Marco; Kamm, Roger D

2018-01-01

Microfluidic devices enable novel means of emulating neurodegenerative disease pathophysiology in vitro. These organ-on-a-chip systems can potentially reduce animal testing and substitute (or augment) simple 2D culture systems. Reconstituting critical features of neurodegenerative diseases in a biomimetic system using microfluidics can thereby accelerate drug discovery and improve our understanding of the mechanisms of several currently incurable diseases. This review describes latest advances in modeling neurodegenerative diseases in the central nervous system and the peripheral nervous system. First, this study summarizes fundamental advantages of microfluidic devices in the creation of compartmentalized cell culture microenvironments for the co-culture of neurons, glial cells, endothelial cells, and skeletal muscle cells and in their recapitulation of spatiotemporal chemical gradients and mechanical microenvironments. Then, this reviews neurodegenerative-disease-on-a-chip models focusing on Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. Finally, this study discusses about current drawbacks of these models and strategies that may overcome them. These organ-on-chip technologies can be useful to be the first line of testing line in drug development and toxicology studies, which can contribute significantly to minimize the phase of animal testing steps. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Asset surveillance system: apparatus and method

NASA Technical Reports Server (NTRS)

Bickford, Randall L. (Inventor)

2007-01-01

System and method for providing surveillance of an asset comprised of numerically fitting at least one mathematical model to obtained residual data correlative to asset operation; storing at least one mathematical model in a memory; obtaining a current set of signal data from the asset; retrieving at least one mathematical model from the memory, using the retrieved mathematical model in a sequential hypothesis test for determining if the current set of signal data is indicative of a fault condition; determining an asset fault cause correlative to a determined indication of a fault condition; providing an indication correlative to a determined fault cause, and an action when warranted. The residual data can be mode partitioned, a current mode of operation can be determined from the asset, and at least one mathematical model can be retrieved from the memory as a function of the determined mode of operation.

A fully dynamic magneto-rheological fluid damper model

NASA Astrophysics Data System (ADS)

Jiang, Z.; Christenson, R. E.

2012-06-01

Control devices can be used to dissipate the energy of a civil structure subjected to dynamic loading, thus reducing structural damage and preventing failure. Semiactive control devices have received significant attention in recent years. The magneto-rheological (MR) fluid damper is a promising type of semiactive device for civil structures due to its mechanical simplicity, inherent stability, high dynamic range, large temperature operating range, robust performance, and low power requirements. The MR damper is intrinsically nonlinear and rate-dependent, both as a function of the displacement across the MR damper and the command current being supplied to the MR damper. As such, to develop control algorithms that take maximum advantage of the unique features of the MR damper, accurate models must be developed to describe its behavior for both displacement and current. In this paper, a new MR damper model that includes a model of the pulse-width modulated (PWM) power amplifier providing current to the damper, a proposed model of the time varying inductance of the large-scale 200 kN MR dampers coils and surrounding MR fluid—a dynamic behavior that is not typically modeled—and a hyperbolic tangent model of the controllable force behavior of the MR damper is presented. Validation experimental tests are conducted with two 200 kN large-scale MR dampers located at the Smart Structures Technology Laboratory (SSTL) at the University of Illinois at Urbana-Champaign and the Lehigh University Network for Earthquake Engineering Simulation (NEES) facility. Comparison with experimental test results for both prescribed motion and current and real-time hybrid simulation of semiactive control of the MR damper shows that the proposed MR damper model can accurately predict the fully dynamic behavior of the large-scale 200 kN MR damper.

Risk Estimation Modeling and Feasibility Testing for a Mobile eHealth Intervention for Binge Drinking Among Young People: The D-ARIANNA (Digital-Alcohol RIsk Alertness Notifying Network for Adolescents and young adults) Project.

PubMed

Carrà, Giuseppe; Crocamo, Cristina; Schivalocchi, Alessandro; Bartoli, Francesco; Carretta, Daniele; Brambilla, Giulia; Clerici, Massimo

2015-01-01

Binge drinking is common among young people but often relevant risk factors are not recognized. eHealth apps, attractive for young people, may be useful to enhance awareness of this problem. We aimed at developing a current risk estimation model for binge drinking, incorporated into an eHealth app--D-ARIANNA (Digital-Alcohol RIsk Alertness Notifying Network for Adolescents and young adults)--for young people. A longitudinal approach with phase 1 (risk estimation), phase 2 (design), and phase 3 (feasibility) was followed. Risk/protective factors identified from the literature were used to develop a current risk estimation model for binge drinking. Relevant odds ratios were subsequently pooled through meta-analytic techniques with a random-effects model, deriving weighted estimates to be introduced in a final model. A set of questions, matching identified risk factors, were nested in a questionnaire and assessed for wording, content, and acceptability in focus groups involving 110 adolescents and young adults. Ten risk factors (5 modifiable) and 2 protective factors showed significant associations with binge drinking and were included in the model. Their weighted coefficients ranged between -0.71 (school proficiency) and 1.90 (cannabis use). The model, nested in an eHealth app questionnaire, provides in percent an overall current risk score, accompanied by appropriate images. Factors that mostly contribute are shown in summary messages. Minor changes have been realized after focus groups review. Most of the subjects (74%) regarded the eHealth app as helpful to assess binge drinking risk. We could produce an evidence-based eHealth app for young people, evaluating current risk for binge drinking. Its effectiveness will be tested in a large trial.

Improved hydrological model parametrization for climate change impact assessment under data scarcity - The potential of field monitoring techniques and geostatistics.

PubMed

Meyer, Swen; Blaschek, Michael; Duttmann, Rainer; Ludwig, Ralf

2016-02-01

According to current climate projections, Mediterranean countries are at high risk for an even pronounced susceptibility to changes in the hydrological budget and extremes. These changes are expected to have severe direct impacts on the management of water resources, agricultural productivity and drinking water supply. Current projections of future hydrological change, based on regional climate model results and subsequent hydrological modeling schemes, are very uncertain and poorly validated. The Rio Mannu di San Sperate Basin, located in Sardinia, Italy, is one test site of the CLIMB project. The Water Simulation Model (WaSiM) was set up to model current and future hydrological conditions. The availability of measured meteorological and hydrological data is poor as it is common for many Mediterranean catchments. In this study we conducted a soil sampling campaign in the Rio Mannu catchment. We tested different deterministic and hybrid geostatistical interpolation methods on soil textures and tested the performance of the applied models. We calculated a new soil texture map based on the best prediction method. The soil model in WaSiM was set up with the improved new soil information. The simulation results were compared to standard soil parametrization. WaSiMs was validated with spatial evapotranspiration rates using the triangle method (Jiang and Islam, 1999). WaSiM was driven with the meteorological forcing taken from 4 different ENSEMBLES climate projections for a reference (1971-2000) and a future (2041-2070) times series. The climate change impact was assessed based on differences between reference and future time series. The simulated results show a reduction of all hydrological quantities in the future in the spring season. Furthermore simulation results reveal an earlier onset of dry conditions in the catchment. We show that a solid soil model setup based on short-term field measurements can improve long-term modeling results, which is especially important in ungauged catchments. Copyright © 2015 Elsevier B.V. All rights reserved.

Analysis of transient state in HTS tapes under ripple DC load current

NASA Astrophysics Data System (ADS)

Stepien, M.; Grzesik, B.

2014-05-01

The paper concerns the analysis of transient state (quench transition) in HTS tapes loaded with the current having DC component together with a ripple component. Two shapes of the ripple were taken into account: sinusoidal and triangular. Very often HTS tape connected to a power electronic current supply (i.e. superconducting coil for SMES) that delivers DC current with ripples and it needs to be examined under such conditions. Additionally, measurements of electrical (and thermal) parameters under such ripple excitation is useful to tape characterization in broad range of load currents. The results presented in the paper were obtained using test bench which contains programmable DC supply and National Instruments data acquisition system. Voltage drops and load currents were measured vs. time. Analysis of measured parameters as a function of the current was used to tape description with quench dynamics taken into account. Results of measurements were also used to comparison with the results of numerical modelling based on FEM. Presented provisional results show possibility to use results of measurements in transient state to prepare inverse models of superconductors and their detailed numerical modelling.

Performance Assessment of Model-Based Optimal Feedforward and Feedback Current Profile Control in NSTX-U using the TRANSP Code

NASA Astrophysics Data System (ADS)

Ilhan, Z.; Wehner, W. P.; Schuster, E.; Boyer, M. D.; Gates, D. A.; Gerhardt, S.; Menard, J.

2015-11-01

Active control of the toroidal current density profile is crucial to achieve and maintain high-performance, MHD-stable plasma operation in NSTX-U. A first-principles-driven, control-oriented model describing the temporal evolution of the current profile has been proposed earlier by combining the magnetic diffusion equation with empirical correlations obtained at NSTX-U for the electron density, electron temperature, and non-inductive current drives. A feedforward + feedback control scheme for the requlation of the current profile is constructed by embedding the proposed nonlinear, physics-based model into the control design process. Firstly, nonlinear optimization techniques are used to design feedforward actuator trajectories that steer the plasma to a desired operating state with the objective of supporting the traditional trial-and-error experimental process of advanced scenario planning. Secondly, a feedback control algorithm to track a desired current profile evolution is developed with the goal of adding robustness to the overall control scheme. The effectiveness of the combined feedforward + feedback control algorithm for current profile regulation is tested in predictive simulations carried out in TRANSP. Supported by PPPL.

Modeling, design, and testing of a proof-of-concept prototype damper with friction and eddy current damping effects

NASA Astrophysics Data System (ADS)

Amjadian, Mohsen; Agrawal, Anil K.

2018-01-01

Friction is considered as one of the most reliable mechanisms of energy dissipation that has been utilized extensively in passive damping devices to mitigate vibration of civil engineering structures subjected to extreme natural hazards such as earthquakes and windstorms. However, passive friction dampers are well-known for having a highly nonlinear hysteretic behavior caused by stick-slip motion at low velocities, a phenomenon that is inherent in friction and increases the acceleration response of the structure under control unfavorably. The authors have recently proposed the theoretical concept of a new type of damping device termed as "Passive Electromagnetic Eddy Current Friction Damper" (PEMECFD) in which an eddy current damping mechanism was utilized not only to decrease the undesirable effects of stick-slip motion, but also to increase the energy dissipation capacity of the damping device as a whole. That study was focused on demonstration of the theoretical performance of the proposed damping device through numerical simulations. This paper further investigates the influence of eddy current damping on energy dissipation due to friction through modeling, design, and testing of a proof-of-concept prototype damper. The design of this damper has been improved over the design in the previous study. The normal force in this damper is produced by the repulsive magnetic force between two cuboidal permanent magnets (PMs) magnetized in the direction normal to the direction of the motion. The eddy current damping force is generated because of the motion of the two PMs and two additional PMs relative to a copper plate in their vicinity. The dynamic models for the force-displacement relationship of the prototype damper are based on LuGre friction model, electromagnetic theory, and inertial effects of the prototype damper. The parameters of the dynamic models have been identified through a series of characterization tests on the prototype damper under harmonic excitations of different frequencies in the laboratory. Finally, the identified dynamic models have been validated by subjecting the prototype damper to two different random excitations. The results indicate that the proposed dynamic models are capable of representing force-displacement behavior of the new type of passive damping device for a wide range of operating conditions.

Quarterly Research Performance Progress Report (2015 Q3). Ultrasonic Phased Arrays and Interactive Reflectivity Tomography for Nondestructive Inspection of Injection and Production Wells in Geothermal Energy Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Santos-Villalobos, Hector J; Polsky, Yarom; Kisner, Roger A

2015-09-01

For the past quarter, we have placed our effort in implementing the first version of the ModelBased Iterative Reconstruction (MBIR) algorithm, assembling and testing the electronics, designing transducers mounts, and defining our laboratory test samples. We have successfully developed the first implementation of MBIR for ultrasound imaging. The current algorithm was tested with synthetic data and we are currently making new modifications for the reconstruction of real ultrasound data. Beside assembling and testing the electronics, we developed a LabView graphic user interface (GUI) to fully control the ultrasonic phased array, adjust the time-delays of the transducers, and store the measuredmore » reflections. As part of preparing for a laboratory-scale demonstration, the design and fabrication of the laboratory samples has begun. Three cement blocks with embedded objects will be fabricated, characterized, and used to demonstrate the capabilities of the system. During the next quarter, we will continue to improve the current MBIR forward model and integrate the reconstruction code with the LabView GUI. In addition, we will define focal laws for the ultrasonic phased array and perform the laboratory demonstration. We expect to perform laboratory demonstration by the end of October 2015.« less

Development of self-control in children aged 3 to 9 years: Perspective from a dual-systems model

PubMed Central

Tao, Ting; Wang, Ligang; Fan, Chunlei; Gao, Wenbin

2014-01-01

The current study tested a set of interrelated theoretical propositions based on a dual-systems model of self-control. Data were collected from 2135 children aged 3 to 9 years. The results suggest that (a) there was positive growth in good self-control, whereas poor control remained relatively stable; and (b) girls performed better than boys on tests of good self-control. The results are discussed in terms of their implications for a dual-systems model of self-control theory and future empirical work. PMID:25501669

Viscoelastic and fatigue properties of model methacrylate-based dentin adhesives

PubMed Central

Singh, Viraj; Misra, Anil; Marangos, Orestes; Park, Jonggu; Ye, Qiang; Kieweg, Sarah L.; Spencer, Paulette

2013-01-01

The objective of the current study is to characterize the viscoelastic and fatigue properties of model methacrylate-based dentin adhesives under dry and wet conditions. Static, creep, and fatigue tests were performed on cylindrical samples in a 3-point bending clamp. Static results showed that the apparent elastic modulus of the model adhesive varied from 2.56 to 3.53 GPa in the dry condition, and from 1.04 to 1.62 GPa in the wet condition, depending upon the rate of loading. Significant differences were also found for the creep behavior of the model adhesive under dry and wet conditions. A linear viscoelastic model was developed by fitting the adhesive creep behavior. The developed model with 5 Kelvin Voigt elements predicted the apparent elastic moduli measured in the static tests. The model was then utilized to interpret the fatigue test results. It was found that the failure under cyclic loading can be due to creep or fatigue, which has implications for the failure criterion that are applied for these types of tests. Finally, it was found that the adhesive samples tested under dry conditions were more durable than those tested under wet conditions. PMID:20848661

Comprehensive Modeling of Temperature-Dependent Degradation Mechanisms in Lithium Iron Phosphate Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schimpe, Michael; von Kuepach, M. E.; Naumann, M.

For reliable lifetime predictions of lithium-ion batteries, models for cell degradation are required. A comprehensive semi-empirical model based on a reduced set of internal cell parameters and physically justified degradation functions for the capacity loss is developed and presented for a commercial lithium iron phosphate/graphite cell. One calendar and several cycle aging effects are modeled separately. Emphasis is placed on the varying degradation at different temperatures. Degradation mechanisms for cycle aging at high and low temperatures as well as the increased cycling degradation at high state of charge are calculated separately. For parameterization, a lifetime test study is conducted includingmore » storage and cycle tests. Additionally, the model is validated through a dynamic current profile based on real-world application in a stationary energy storage system revealing the accuracy. Tests for validation are continued for up to 114 days after the longest parametrization tests. In conclusion, the model error for the cell capacity loss in the application-based tests is at the end of testing below 1% of the original cell capacity and the maximum relative model error is below 21%.« less

Comprehensive Modeling of Temperature-Dependent Degradation Mechanisms in Lithium Iron Phosphate Batteries

DOE PAGES

Schimpe, Michael; von Kuepach, M. E.; Naumann, M.; ...

2018-01-12

For reliable lifetime predictions of lithium-ion batteries, models for cell degradation are required. A comprehensive semi-empirical model based on a reduced set of internal cell parameters and physically justified degradation functions for the capacity loss is developed and presented for a commercial lithium iron phosphate/graphite cell. One calendar and several cycle aging effects are modeled separately. Emphasis is placed on the varying degradation at different temperatures. Degradation mechanisms for cycle aging at high and low temperatures as well as the increased cycling degradation at high state of charge are calculated separately. For parameterization, a lifetime test study is conducted includingmore » storage and cycle tests. Additionally, the model is validated through a dynamic current profile based on real-world application in a stationary energy storage system revealing the accuracy. Tests for validation are continued for up to 114 days after the longest parametrization tests. In conclusion, the model error for the cell capacity loss in the application-based tests is at the end of testing below 1% of the original cell capacity and the maximum relative model error is below 21%.« less

The scaling of model test results to predict intake hot gas reingestion for STOVL aircraft with augmented vectored thrust engines

NASA Technical Reports Server (NTRS)

Penrose, C. J.

1987-01-01

The difficulties of modeling the complex recirculating flow fields produced by multiple jet STOVL aircraft close to the ground have led to extensive use of experimental model tests to predict intake Hot Gas Reingestion (HGR). Model test results reliability is dependent on a satisfactory set of scaling rules which must be validated by fully comparable full scale tests. Scaling rules devised in the U.K. in the mid 60's gave good model/full scale agreement for the BAe P1127 aircraft. Until recently no opportunity has occurred to check the applicability of the rules to the high energy exhaust of current ASTOVL aircraft projects. Such an opportunity has arisen following tests on a Tethered Harrier. Comparison of this full scale data and results from tests on a model configuration approximating to the full scale aircraft geometry has shown discrepancies between HGR levels. These discrepancies although probably due to geometry and other model/scale differences indicate some reexamination of the scaling rules is needed. Therefore the scaling rules are reviewed, further scaling studies planned are described and potential areas for further work are suggested.

Models for Scoring Missing Responses to Multiple-Choice Items. Program Statistics Research Technical Report No. 94-1.

ERIC Educational Resources Information Center

Longford, Nicholas T.

This study is a critical evaluation of the roles for coding and scoring of missing responses to multiple-choice items in educational tests. The focus is on tests in which the test-takers have little or no motivation; in such tests omitting and not reaching (as classified by the currently adopted operational rules) is quite frequent. Data from the…

Design and Experimental Study of a Current Transformer with a Stacked PCB Based on B-Dot.

PubMed

Wang, Jingang; Si, Diancheng; Tian, Tian; Ren, Ran

2017-04-10

An electronic current transformer with a B-dot sensor is proposed in this study. The B-dot sensor can realize the current measurement of the transmission line in a non-contact way in accordance with the principle of magnetic field coupling. The multiple electrodes series-opposing structure is applied together with differential input structures and active integrating circuits, which can allow the sensor to operate in differential mode. Maxwell software is adopted to model and simulate the sensor. Optimization of the sensor structural parameters is conducted through finite-element simulation. A test platform is built to conduct the steady-state characteristic, on-off operation, and linearity tests for the designed current transformer under the power-frequency current. As shown by the test results, in contrast with traditional electromagnetic CT, the designed current transformer can achieve high accuracy and good phase-frequency; its linearity is also very good at different distances from the wire. The proposed current transformer provides a new method for electricity larceny prevention and on-line monitoring of the power grid in an electric system, thereby satisfying the development demands of the smart power grid.

Design and Experimental Study of a Current Transformer with a Stacked PCB Based on B-Dot

PubMed Central

Wang, Jingang; Si, Diancheng; Tian, Tian; Ren, Ran

2017-01-01

An electronic current transformer with a B-dot sensor is proposed in this study. The B-dot sensor can realize the current measurement of the transmission line in a non-contact way in accordance with the principle of magnetic field coupling. The multiple electrodes series-opposing structure is applied together with differential input structures and active integrating circuits, which can allow the sensor to operate in differential mode. Maxwell software is adopted to model and simulate the sensor. Optimization of the sensor structural parameters is conducted through finite-element simulation. A test platform is built to conduct the steady-state characteristic, on-off operation, and linearity tests for the designed current transformer under the power-frequency current. As shown by the test results, in contrast with traditional electromagnetic CT, the designed current transformer can achieve high accuracy and good phase-frequency; its linearity is also very good at different distances from the wire. The proposed current transformer provides a new method for electricity larceny prevention and on-line monitoring of the power grid in an electric system, thereby satisfying the development demands of the smart power grid. PMID:28394298

Electromigration Mechanism of Failure in Flip-Chip Solder Joints Based on Discrete Void Formation.

PubMed

Chang, Yuan-Wei; Cheng, Yin; Helfen, Lukas; Xu, Feng; Tian, Tian; Scheel, Mario; Di Michiel, Marco; Chen, Chih; Tu, King-Ning; Baumbach, Tilo

2017-12-20

In this investigation, SnAgCu and SN100C solders were electromigration (EM) tested, and the 3D laminography imaging technique was employed for in-situ observation of the microstructure evolution during testing. We found that discrete voids nucleate, grow and coalesce along the intermetallic compound/solder interface during EM testing. A systematic analysis yields quantitative information on the number, volume, and growth rate of voids, and the EM parameter of DZ*. We observe that fast intrinsic diffusion in SnAgCu solder causes void growth and coalescence, while in the SN100C solder this coalescence was not significant. To deduce the current density distribution, finite-element models were constructed on the basis of the laminography images. The discrete voids do not change the global current density distribution, but they induce the local current crowding around the voids: this local current crowding enhances the lateral void growth and coalescence. The correlation between the current density and the probability of void formation indicates that a threshold current density exists for the activation of void formation. There is a significant increase in the probability of void formation when the current density exceeds half of the maximum value.

Mutual coupling effects in antenna arrays, volume 1

NASA Technical Reports Server (NTRS)

Collin, R. E.

1986-01-01

Mutual coupling between rectangular apertures in a finite antenna array, in an infinite ground plane, is analyzed using the vector potential approach. The method of moments is used to solve the equations that result from setting the tangential magnetic fields across each aperture equal. The approximation uses a set of vector potential model functions to solve for equivalent magnetic currents. A computer program was written to carry out this analysis and the resulting currents were used to determine the co- and cross-polarized far zone radiation patterns. Numerical results for various arrays using several modes in the approximation are presented. Results for one and two aperture arrays are compared against published data to check on the agreement of this model with previous work. Computer derived results are also compared against experimental results to test the accuracy of the model. These tests of the accuracy of the program showed that it yields valid data.

Test systems in drug discovery for hazard identification and risk assessment of human drug-induced liver injury.

PubMed

Weaver, Richard J; Betts, Catherine; Blomme, Eric A G; Gerets, Helga H J; Gjervig Jensen, Klaus; Hewitt, Philip G; Juhila, Satu; Labbe, Gilles; Liguori, Michael J; Mesens, Natalie; Ogese, Monday O; Persson, Mikael; Snoeys, Jan; Stevens, James L; Walker, Tracy; Park, B Kevin

2017-07-01

The liver is an important target for drug-induced toxicities. Early detection of hepatotoxic drugs requires use of well-characterized test systems, yet current knowledge, gaps and limitations of tests employed remains an important issue for drug development. Areas Covered: The current state of the science, understanding and application of test systems in use for the detection of drug-induced cytotoxicity, mitochondrial toxicity, cholestasis and inflammation is summarized. The test systems highlighted herein cover mostly in vitro and some in vivo models and endpoint measurements used in the assessment of small molecule toxic liabilities. Opportunities for research efforts in areas necessitating the development of specific tests and improved mechanistic understanding are highlighted. Expert Opinion: Use of in vitro test systems for safety optimization will remain a core activity in drug discovery. Substantial inroads have been made with a number of assays established for human Drug-induced Liver Injury. There nevertheless remain significant gaps with a need for improved in vitro tools and novel tests to address specific mechanisms of human Drug-Induced Liver Injury. Progress in these areas will necessitate not only models fit for application, but also mechanistic understanding of how chemical insult on the liver occurs in order to identify translational and quantifiable readouts for decision-making.

UTM Weather Presentation

NASA Technical Reports Server (NTRS)

Chan, William N.; Kopardekar, Parimal H.; Carmichael, Bruce; Cornman, Larry

2017-01-01

Presentation highlighting how weather affected UAS operations during the UTM field tests. Research to develop UAS weather translation models with a description of current and future work for UTM weather.

EFFECTS OF CLIMATE CHANGE ON WEATHER AND WATER

EPA Science Inventory

Information regarding weather and hydrological processes and how they may change in the future is available from a variety of dynamically downscaled climate models. Current studies are helping to improve the use of such models for regional climate impact studies by testing the s...

Characterization of Human Neural Progenitor Cell Models for Developmental Neurotoxicity Screening

EPA Science Inventory

Current testing methods for developmental neurotoxicity (DNT) make evaluation of the effects of large numbers of chemicals impractical and prohibitively expensive. As such, we are evaluating two different human neural progenitor cell (hNPC) models for their utility in screens for...

Predicting in-patient falls in a geriatric clinic: a clinical study combining assessment data and simple sensory gait measurements.

PubMed

Marschollek, M; Nemitz, G; Gietzelt, M; Wolf, K H; Meyer Zu Schwabedissen, H; Haux, R

2009-08-01

Falls are among the predominant causes for morbidity and mortality in elderly persons and occur most often in geriatric clinics. Despite several studies that have identified parameters associated with elderly patients' fall risk, prediction models -- e.g., based on geriatric assessment data -- are currently not used on a regular basis. Furthermore, technical aids to objectively assess mobility-associated parameters are currently not used. To assess group differences in clinical as well as common geriatric assessment data and sensory gait measurements between fallers and non-fallers in a geriatric sample, and to derive and compare two prediction models based on assessment data alone (model #1) and added sensory measurement data (model #2). For a sample of n=110 geriatric in-patients (81 women, 29 men) the following fall risk-associated assessments were performed: Timed 'Up & Go' (TUG) test, STRATIFY score and Barthel index. During the TUG test the subjects wore a triaxial accelerometer, and sensory gait parameters were extracted from the data recorded. Group differences between fallers (n=26) and non-fallers (n=84) were compared using Student's t-test. Two classification tree prediction models were computed and compared. Significant differences between the two groups were found for the following parameters: time to complete the TUG test, transfer item (Barthel), recent falls (STRATIFY), pelvic sway while walking and step length. Prediction model #1 (using common assessment data only) showed a sensitivity of 38.5% and a specificity of 97.6%, prediction model #2 (assessment data plus sensory gait parameters) performed with 57.7% and 100%, respectively. Significant differences between fallers and non-fallers among geriatric in-patients can be detected for several assessment subscores as well as parameters recorded by simple accelerometric measurements during a common mobility test. Existing geriatric assessment data may be used for falls prediction on a regular basis. Adding sensory data improves the specificity of our test markedly.

Magnetic emissions testing of the space station engineering model resistojet

NASA Technical Reports Server (NTRS)

Briehl, Daniel

1988-01-01

The engineering model resistojet intended for altitude maintenance onboard the space station was tested for magnetic radiation emissions in the Radio Frequency Interference (RFI) facility at the Goddard Space Flight Center. The resistojet heater was supplied with power at 20 kHz and low voltage through a power controller. The resistojet was isolated from its power supply in the RFI enclosure, and the magnetic emission measured at three locations around the resistojet at various heater currents. At a heater current of 18.5 A the maximum magnetic emission was 61 dBpt at a distance of 1 m from the resistojet and at a location at the rear of the thruster. Calculations indicate that the case and heat shields provided a minimum of 4 dB of attenuation at a current of 18.5 A. Maximum radiation was measured at the rear of the resistojet along its major axis and was thought to be due to the magnetic radiation from the power leads. At a distance of 37 cm from the resistojet the maximum magnetic radiation measured was 73 dBpt at a current of 11.2 A. The power input leads were also a source of magnetic radiation. The engineering model rssistojet requires about 20 dB of additional shielding.

Effects of Droplet Size on Intrusion of Sub-Surface Oil Spills

NASA Astrophysics Data System (ADS)

Adams, Eric; Chan, Godine; Wang, Dayang

2014-11-01

We explore effects of droplet size on droplet intrusion and transport in sub-surface oil spills. Negatively buoyant glass beads released continuously to a stratified ambient simulate oil droplets in a rising multiphase plume, and distributions of settled beads are used to infer signatures of surfacing oil. Initial tests used quiescent conditions, while ongoing tests simulate currents by towing the source and a bottom sled. Without current, deposited beads have a Gaussian distribution, with variance increasing with decreasing particle size. Distributions agree with a model assuming first order particle loss from an intrusion layer of constant thickness, and empirically determined flow rate. With current, deposited beads display a parabolic distribution similar to that expected from a source in uniform flow; we are currently comparing observed distributions with similar analytical models. Because chemical dispersants have been used to reduce oil droplet size, our study provides one measure of their effectiveness. Results are applied to conditions from the `Deep Spill' field experiment, and the recent Deepwater Horizon oil spill, and are being used to provide ``inner boundary conditions'' for subsequent far field modeling of these events. This research was made possible by grants from Chevron Energy Technology Co., through the Chevron-MITEI University Partnership Program, and BP/The Gulf of Mexico Research Initiative, GISR.

Variational analysis of drifter positions and model outputs for the reconstruction of surface currents in the central Adriatic during fall 2002

USGS Publications Warehouse

Taillandier, V.; Griffa, A.; Poulain, P.-M.; Signell, R.; Chiggiato, J.; Carniel, S.

2008-01-01

In this paper we present an application of a variational method for the reconstruction of the velocity field in a coastal flow in the central Adriatic Sea, using in situ data from surface drifters and outputs from the ROMS circulation model. The variational approach, previously developed and tested for mesoscale open ocean flows, has been improved and adapted to account for inhomogeneities on boundary current dynamics over complex bathymetry and coastline and for weak Lagrangian persistence in coastal flows. The velocity reconstruction is performed using nine drifter trajectories over 45 d, and a hierarchy of indirect tests is introduced to evaluate the results as the real ocean state is not known. For internal consistency and impact of the analysis, three diagnostics characterizing the particle prediction and transport, in terms of residence times in various zones and export rates from the boundary current toward the interior, show that the reconstruction is quite effective. A qualitative comparison with sea color data from the MODIS satellite images shows that the reconstruction significantly improves the description of the boundary current with respect to the ROMS model first guess, capturing its main features and its exchanges with the interior when sampled by the drifters. Copyright 2008 by the American Geophysical Union.

Seal Related Development Activities at EG/G

NASA Technical Reports Server (NTRS)

Greiner, Harold F.

1991-01-01

Seal related development activities including modeling, analysis, and performance testing are described for several current seal related projects. Among the current seal related projects are the following: high pressure gas sealing systems for turbomachinery; brush seals for gas path sealing in gas turbines; and tribological material evaluation for wear surfaces in sealing systems.

Cryogenic Optical Performance of a Lightweighted Mirror Assembly for Future Space Astronomical Telescopes: Correlating Optical Test Results and Thermal Optical Model

NASA Technical Reports Server (NTRS)

Eng, Ron; Arnold, William R.; Baker, Marcus A.; Bevan, Ryan M.; Burdick, Gregory; Effinger, Michael R.; Gaddy, Darrell E.; Goode, Brian K.; Hanson, Craig; Hogue, William D.;

Monitoring Maritime Conditions with Unmanned Systems During Trident Warrior 2013

DTIC Science & Technology

2014-01-01

Host- ing Autonomous Remote Craft or SHARC model ) that emit sounds and listen for reflected changes in response to ocean currents. Experiments tested...San Diego Scripps Institution of Oceanography were also deployed; these provided Acoustic Doppler Current Profiler (ADCP) 3D measurements of the...ocean currents as well as measurements of the surface meteorology . Figure 5(b) shows a schematic representa- tion of one wave glider and two ocean

Nursing Students’ Smoking Behaviors and Smoking-Related Self-Concept

DTIC Science & Technology

2003-04-01

The purposes of this pilot study were to describe: (a) the relationships between baccalaureate (BSN) nursing students’ smoking-related current self ...instruments used to describe nursing students’ self -concept, including current smoking-related self -concept and possible selves. A schema model of smoking...collected to gather data on demographics, smoking history, and current self and possible future selves. Nonparametric tests were used to describe group

3-D direct current resistivity anisotropic modelling by goal-oriented adaptive finite element methods

NASA Astrophysics Data System (ADS)

Ren, Zhengyong; Qiu, Lewen; Tang, Jingtian; Wu, Xiaoping; Xiao, Xiao; Zhou, Zilong

2018-01-01

Although accurate numerical solvers for 3-D direct current (DC) isotropic resistivity models are current available even for complicated models with topography, reliable numerical solvers for the anisotropic case are still an open question. This study aims to develop a novel and optimal numerical solver for accurately calculating the DC potentials for complicated models with arbitrary anisotropic conductivity structures in the Earth. First, a secondary potential boundary value problem is derived by considering the topography and the anisotropic conductivity. Then, two a posteriori error estimators with one using the gradient-recovery technique and one measuring the discontinuity of the normal component of current density are developed for the anisotropic cases. Combing the goal-oriented and non-goal-oriented mesh refinements and these two error estimators, four different solving strategies are developed for complicated DC anisotropic forward modelling problems. A synthetic anisotropic two-layer model with analytic solutions verified the accuracy of our algorithms. A half-space model with a buried anisotropic cube and a mountain-valley model are adopted to test the convergence rates of these four solving strategies. We found that the error estimator based on the discontinuity of current density shows better performance than the gradient-recovery based a posteriori error estimator for anisotropic models with conductivity contrasts. Both error estimators working together with goal-oriented concepts can offer optimal mesh density distributions and highly accurate solutions.

Current NASA Earth Remote Sensing Observations

NASA Technical Reports Server (NTRS)

Luvall, Jeffrey C.; Sprigg, William A.; Huete, Alfredo; Pejanovic, Goran; Nickovic, Slobodan; Ponce-Campos, Guillermo; Krapfl, Heide; Budge, Amy; Zelicoff, Alan; Myers, Orrin;

Skill Testing a Three-Dimensional Global Tide Model to Historical Current Meter Records

DTIC Science & Technology

2013-12-17

up to 20% weaker skill in the Southern Ocean. Citation: Timko, P. G., B. K. Arbic, J. G. Richman, R . B. Scott, E. J. Metzger, and A. J. Wallcraft (2013...model were identified from a current meter archive ( CMA ) of approximately 9000 unique time series previously used by Scott et al. [2010] and Timko et al...2012]. The CMA spans 40 years of observations. Some of the velocity records used in this study represents individ- ual depth bins from ADCP’s. The

Fuzzy model-based fault detection and diagnosis for a pilot heat exchanger

NASA Astrophysics Data System (ADS)

Habbi, Hacene; Kidouche, Madjid; Kinnaert, Michel; Zelmat, Mimoun

2011-04-01

This article addresses the design and real-time implementation of a fuzzy model-based fault detection and diagnosis (FDD) system for a pilot co-current heat exchanger. The design method is based on a three-step procedure which involves the identification of data-driven fuzzy rule-based models, the design of a fuzzy residual generator and the evaluation of the residuals for fault diagnosis using statistical tests. The fuzzy FDD mechanism has been implemented and validated on the real co-current heat exchanger, and has been proven to be efficient in detecting and isolating process, sensor and actuator faults.

Human Hemato-Lymphoid System Mice: Current Use and Future Potential for Medicine

PubMed Central

Rongvaux, Anthony; Takizawa, Hitoshi; Strowig, Till; Willinger, Tim; Eynon, Elizabeth E.

2014-01-01

To directly study complex human hemato-lymphoid system physiology and respective system-associated diseases in vivo, human-to-mouse xenotransplantation models for human blood and blood-forming cells and organs have been developed over the past three decades. We here review the fundamental requirements and the remarkable progress made over the past few years in improving these systems, the current major achievements reached by use of these models, and the future challenges to more closely model and study human health and disease and to achieve predictive preclinical testing of both prevention measures and potential new therapies. PMID:23330956

Dark energy and equivalence principle constraints from astrophysical tests of the stability of the fine-structure constant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martins, C.J.A.P.; Pinho, A.M.M.; Alves, R.F.C.

2015-08-01

Astrophysical tests of the stability of fundamental couplings, such as the fine-structure constant α, are becoming an increasingly powerful probe of new physics. Here we discuss how these measurements, combined with local atomic clock tests and Type Ia supernova and Hubble parameter data, constrain the simplest class of dynamical dark energy models where the same degree of freedom is assumed to provide both the dark energy and (through a dimensionless coupling, ζ, to the electromagnetic sector) the α variation. Specifically, current data tightly constrains a combination of ζ and the present dark energy equation of state w{sub 0}. Moreover, inmore » these models the new degree of freedom inevitably couples to nucleons (through the α dependence of their masses) and leads to violations of the Weak Equivalence Principle. We obtain indirect bounds on the Eötvös parameter η that are typically stronger than the current direct ones. We discuss the model-dependence of our results and briefly comment on how the forthcoming generation of high-resolution ultra-stable spectrographs will enable significantly tighter constraints.« less

Experimental flutter boundaries with unsteady pressure distributions for the NACA 0012 Benchmark Model

NASA Technical Reports Server (NTRS)

Rivera, Jose A., Jr.; Dansberry, Bryan E.; Farmer, Moses G.; Eckstrom, Clinton V.; Seidel, David A.; Bennett, Robert M.

1991-01-01

The Structural Dynamics Div. at NASA-Langley has started a wind tunnel activity referred to as the Benchmark Models Program. The objective is to acquire test data that will be useful for developing and evaluating aeroelastic type Computational Fluid Dynamics codes currently in use or under development. The progress is described which was achieved in testing the first model in the Benchmark Models Program. Experimental flutter boundaries are presented for a rigid semispan model (NACA 0012 airfoil section) mounted on a flexible mount system. Also, steady and unsteady pressure measurements taken at the flutter condition are presented. The pressure data were acquired over the entire model chord located at the 60 pct. span station.

Extravehicular Mobility Unit Penetration Probability from Micrometeoroids and Orbital Debris: Revised Analytical Model and Potential Space Suit Improvements

NASA Technical Reports Server (NTRS)

Chase, Thomas D.; Splawn, Keith; Christiansen, Eric L.

2007-01-01

The NASA Extravehicular Mobility Unit (EMU) micrometeoroid and orbital debris protection ability has recently been assessed against an updated, higher threat space environment model. The new environment was analyzed in conjunction with a revised EMU solid model using a NASA computer code. Results showed that the EMU exceeds the required mathematical Probability of having No Penetrations (PNP) of any suit pressure bladder over the remaining life of the program (2,700 projected hours of 2 person spacewalks). The success probability was calculated to be 0.94, versus a requirement of >0.91, for the current spacesuit s outer protective garment. In parallel to the probability assessment, potential improvements to the current spacesuit s outer protective garment were built and impact tested. A NASA light gas gun was used to launch projectiles at test items, at speeds of approximately 7 km per second. Test results showed that substantial garment improvements could be made, with mild material enhancements and moderate assembly development. The spacesuit s PNP would improve marginally with the tested enhancements, if they were available for immediate incorporation. This paper discusses the results of the model assessment process and test program. These findings add confidence to the continued use of the existing NASA EMU during International Space Station (ISS) assembly and Shuttle Operations. They provide a viable avenue for improved hypervelocity impact protection for the EMU, or for future space suits.

Improving freight fire safety : experiment testing and computer modeling to further development of mist-controlling additives for fire mitigation.

DOT National Transportation Integrated Search

2012-08-01

With the purpose to minimize or prevent crash-induced fires in road and rail transportation, the : current interest in bio-derived and blended transportation fuels is increasing. Based on two years : of preliminary testing and analysis, it appears to...

Informing Selection of Nanomaterial Concentrations for ToxCast In Vitro Testing using the Multi-Path Particle Dosimetry Model

EPA Science Inventory

Currently, little justification is provided for nanomaterial testing concentrations in in vitro assays. The in vitro concentrations typically used may be higher than those experienced in exposed humans. Selection of concentration levels for hazard evaluation based on real-world ...

Bridging the gap between theoretical ecology and real ecosystems: modeling invertebrate community composition in streams.

PubMed

Schuwirth, Nele; Reichert, Peter

2013-02-01

For the first time, we combine concepts of theoretical food web modeling, the metabolic theory of ecology, and ecological stoichiometry with the use of functional trait databases to predict the coexistence of invertebrate taxa in streams. We developed a mechanistic model that describes growth, death, and respiration of different taxa dependent on various environmental influence factors to estimate survival or extinction. Parameter and input uncertainty is propagated to model results. Such a model is needed to test our current quantitative understanding of ecosystem structure and function and to predict effects of anthropogenic impacts and restoration efforts. The model was tested using macroinvertebrate monitoring data from a catchment of the Swiss Plateau. Even without fitting model parameters, the model is able to represent key patterns of the coexistence structure of invertebrates at sites varying in external conditions (litter input, shading, water quality). This confirms the suitability of the model concept. More comprehensive testing and resulting model adaptations will further increase the predictive accuracy of the model.

Geotechnical studies relevant to the containment of underground nuclear explosions at the Nevada Test Site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heuze, F.E.

1982-05-01

The Department of Energy and the Department of Defense are actively pursuing a program of nuclear weapons testing by underground explosions at the Nevada Test Site (NTS). Over the past 11 years, scores of tests have been conducted and the safety record is very good. In the short run, emphasis is put on preventing the release of radioactive materials into the atmosphere. In the long run, the subsidence and collapse of the ground above the nuclear cavities also are matters of interest. Currently, estimation of containment is based mostly on empiricism derived from extensive experience and on a combination ofmore » physical/mechanical testing and numerical modeling. When measured directly, the mechanical material properties are obtained from short-term laboratory tests on small, conventional samples. This practice does not determine the large effects of scale and time on measured stiffnesses and strengths of geological materials. Because of the limited data base of properties and in situ conditions, the input to otherwise fairly sophisticated computer programs is subject to several simplifying assumptions; some of them can have a nonconservative impact on the calculated results. As for the long-term, subsidence and collapse phenomena simply have not been studied to any significant degree. This report examines the geomechanical aspects of procedures currently used to estimate containment of undergroung explosions at NTS. Based on this examination, it is concluded that state-of-the-art geological engineering practice in the areas of field testing, large scale laboratory measurements, and numerical modeling can be drawn upon to complement the current approach.« less

Current Topics in Postnatal Behavioral Testing.

PubMed

Henck, Judith W; Elayan, Ikram; Vorhees, Charles; Fisher, J Edward; Morford, LaRonda L

2016-09-01

The study of developmental neurotoxicity (DNT) continues to be an important component of safety evaluation of candidate therapeutic agents and of industrial and environmental chemicals. Developmental neurotoxicity is considered to be an adverse change in the central and/or peripheral nervous system during development of an organism and has been primarily evaluated by studying functional outcomes, such as changes in behavior, neuropathology, neurochemistry, and/or neurophysiology. Neurobehavioral evaluations are a component of a wide range of toxicology studies in laboratory animal models, whereas neurochemistry and neurophysiology are less commonly employed. Although the primary focus of this article is on neurobehavioral evaluation in pre- and postnatal development and juvenile toxicology studies used in pharmaceutical development, concepts may also apply to adult nonclinical safety studies and Environmental Protection Agency/chemical assessments. This article summarizes the proceedings of a symposium held during the 2015 American College of Toxicology annual meeting and includes a discussion of the current status of DNT testing as well as potential issues and recommendations. Topics include the regulatory context for DNT testing; study design and interpretation; behavioral test selection, including a comparison of core learning and memory systems; age of testing; repeated testing of the same animals; use of alternative animal models; impact of findings; and extrapolation of animal results to humans. Integration of the regulatory experience and scientific concepts presented during this symposium, as well as from subsequent discussion and input, provides a synopsis of the current state of DNT testing in safety assessment, as well as a potential roadmap for future advancement. © The Author(s) 2016.

Influence of magnet eddy current on magnetization characteristics of variable flux memory machine

NASA Astrophysics Data System (ADS)

Yang, Hui; Lin, Heyun; Zhu, Z. Q.; Lyu, Shukang

2018-05-01

In this paper, the magnet eddy current characteristics of a newly developed variable flux memory machine (VFMM) is investigated. Firstly, the machine structure, non-linear hysteresis characteristics and eddy current modeling of low coercive force magnet are described, respectively. Besides, the PM eddy current behaviors when applying the demagnetizing current pulses are unveiled and investigated. The mismatch of the required demagnetization currents between the cases with or without considering the magnet eddy current is identified. In addition, the influences of the magnet eddy current on the demagnetization effect of VFMM are analyzed. Finally, a prototype is manufactured and tested to verify the theoretical analyses.

Propfan test assessment testbed aircraft flutter model test report

NASA Technical Reports Server (NTRS)

Jenness, C. M. J.

1987-01-01

The PropFan Test Assessment (PTA) program includes flight tests of a propfan power plant mounted on the left wind of a modified Gulfstream II testbed aircraft. A static balance boom is mounted on the right wing tip for lateral balance. Flutter analyses indicate that these installations reduce the wing flutter stabilizing speed and that torsional stiffening and the installation of a flutter stabilizing tip boom are required on the left wing for adequate flutter safety margins. Wind tunnel tests of a 1/9th scale high speed flutter model of the testbed aircraft were conducted. The test program included the design, fabrication, and testing of the flutter model and the correlation of the flutter test data with analysis results. Excellent correlations with the test data were achieved in posttest flutter analysis using actual model properties. It was concluded that the flutter analysis method used was capable of accurate flutter predictions for both the (symmetric) twin propfan configuration and the (unsymmetric) single propfan configuration. The flutter analysis also revealed that the differences between the tested model configurations and the current aircraft design caused the (scaled) model flutter speed to be significantly higher than that of the aircraft, at least for the single propfan configuration without a flutter boom. Verification of the aircraft final design should, therefore, be based on flutter predictions made with the test validated analysis methods.

Bivariate random-effects meta-analysis models for diagnostic test accuracy studies using arcsine-based transformations.

PubMed

Negeri, Zelalem F; Shaikh, Mateen; Beyene, Joseph

2018-05-11

Diagnostic or screening tests are widely used in medical fields to classify patients according to their disease status. Several statistical models for meta-analysis of diagnostic test accuracy studies have been developed to synthesize test sensitivity and specificity of a diagnostic test of interest. Because of the correlation between test sensitivity and specificity, modeling the two measures using a bivariate model is recommended. In this paper, we extend the current standard bivariate linear mixed model (LMM) by proposing two variance-stabilizing transformations: the arcsine square root and the Freeman-Tukey double arcsine transformation. We compared the performance of the proposed methods with the standard method through simulations using several performance measures. The simulation results showed that our proposed methods performed better than the standard LMM in terms of bias, root mean square error, and coverage probability in most of the scenarios, even when data were generated assuming the standard LMM. We also illustrated the methods using two real data sets. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Embryonic stem cells and the next generation of developmental toxicity testing.

PubMed

Kugler, Josephine; Huhse, Bettina; Tralau, Tewes; Luch, Andreas

2017-08-01

The advent of stem cell technology has seen the establishment of embryonic stem cells (ESCs) as molecular model systems and screening tools. Although ESCs are nowadays widely used in research, regulatory implementation for developmental toxicity testing is pending. Areas Covered: This review evaluates the performance of current ESC, including human (h)ESC testing systems, trying to elucidate their potential for developmental toxicity testing. It shall discuss defining parameters and mechanisms, their relevance and contemplate what can realistically be expected. Crucially this includes the question of how to ascertain the quality of currently employed cell lines and tests based thereon. Finally, the use of hESCs will raise ethical concerns which should be addressed early on. Expert Opinion: While the suitability of (h)ESCs as tools for research and development goes undisputed, any routine use for developmental toxicity testing currently still seems premature. The reasons for this comprise inherent biological deficiencies as well as cell line quality and system validation. Overcoming these issues will require collaboration of scientists, test developers and regulators. Also, validation needs to be made worthwhile for academia. Finally we have to continuously rethink existing strategies, making room for improved testing and innovative approaches.

Comprehensive Modeling of Temperature-Dependent Degradation Mechanisms in Lithium Iron Phosphate Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Kandler A; Schimpe, Michael; von Kuepach, Markus Edler

For reliable lifetime predictions of lithium-ion batteries, models for cell degradation are required. A comprehensive semi-empirical model based on a reduced set of internal cell parameters and physically justified degradation functions for the capacity loss is developed and presented for a commercial lithium iron phosphate/graphite cell. One calendar and several cycle aging effects are modeled separately. Emphasis is placed on the varying degradation at different temperatures. Degradation mechanisms for cycle aging at high and low temperatures as well as the increased cycling degradation at high state of charge are calculated separately.For parameterization, a lifetime test study is conducted including storagemore » and cycle tests. Additionally, the model is validated through a dynamic current profile based on real-world application in a stationary energy storage system revealing the accuracy. The model error for the cell capacity loss in the application-based tests is at the end of testing below 1 % of the original cell capacity.« less

Measurements and analysis of dynamic effects in the LARP model quadrupole HQ02b during rapid discharge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sorbi, Massimo; Ambrosio, Giorgio; Bajas, Hugo

This paper presents the analysis of some quench tests addressed to study the dynamic effects in the 1-m-long 120-mm-aperture Nb 3Sn quadrupole magnet, i.e., HQ02b, designed, fabricated, and tested by the LHC Accelerator Research Program. The magnet has a short sample gradient of 205 T/m at 1.9 K and a peak field of 14.2 T. The test campaign has been performed at CERN in April 2014. In the specific tests, which were dedicated to the measurements of the dynamic inductance of the magnet during the rapid current discharge for a quench, the protection heaters were activated only in some windings,more » in order to obtain the measure of the resistive and inductive voltages separately. The analysis of the results confirms a very low value of the dynamic inductance at the beginning of the discharge, which later approaches the nominal value. Indications of dynamic inductance variation were already found from the analysis of current decay during quenches in the previous magnets HQ02a and HQ02a2; however, with this dedicated test of HQ02b, a quantitative measurement and assessment has been possible. An analytical model using interfilament coupling current influence for the inductance lowering has been implemented in the quench calculation code QLASA, and the comparison with experimental data is given. In conclusion, the agreement of the model with the experimental results is very good and allows predicting more accurately the critical parameters in quench analysis (MIITs, hot spot temperature) for the MQXF Nb3Sn quadrupoles, which will be installed in the High Luminosity LHC.« less

Measurements and analysis of dynamic effects in the LARP model quadrupole HQ02b during rapid discharge

DOE PAGES

Sorbi, Massimo; Ambrosio, Giorgio; Bajas, Hugo; ...

2016-06-01

This paper presents the analysis of some quench tests addressed to study the dynamic effects in the 1-m-long 120-mm-aperture Nb 3Sn quadrupole magnet, i.e., HQ02b, designed, fabricated, and tested by the LHC Accelerator Research Program. The magnet has a short sample gradient of 205 T/m at 1.9 K and a peak field of 14.2 T. The test campaign has been performed at CERN in April 2014. In the specific tests, which were dedicated to the measurements of the dynamic inductance of the magnet during the rapid current discharge for a quench, the protection heaters were activated only in some windings,more » in order to obtain the measure of the resistive and inductive voltages separately. The analysis of the results confirms a very low value of the dynamic inductance at the beginning of the discharge, which later approaches the nominal value. Indications of dynamic inductance variation were already found from the analysis of current decay during quenches in the previous magnets HQ02a and HQ02a2; however, with this dedicated test of HQ02b, a quantitative measurement and assessment has been possible. An analytical model using interfilament coupling current influence for the inductance lowering has been implemented in the quench calculation code QLASA, and the comparison with experimental data is given. In conclusion, the agreement of the model with the experimental results is very good and allows predicting more accurately the critical parameters in quench analysis (MIITs, hot spot temperature) for the MQXF Nb3Sn quadrupoles, which will be installed in the High Luminosity LHC.« less

Transient multi-physics analysis of a magnetorheological shock absorber with the inverse Jiles-Atherton hysteresis model

NASA Astrophysics Data System (ADS)

Zheng, Jiajia; Li, Yancheng; Li, Zhaochun; Wang, Jiong

2015-10-01

This paper presents multi-physics modeling of an MR absorber considering the magnetic hysteresis to capture the nonlinear relationship between the applied current and the generated force under impact loading. The magnetic field, temperature field, and fluid dynamics are represented by the Maxwell equations, conjugate heat transfer equations, and Navier-Stokes equations. These fields are coupled through the apparent viscosity and the magnetic force, both of which in turn depend on the magnetic flux density and the temperature. Based on a parametric study, an inverse Jiles-Atherton hysteresis model is used and implemented for the magnetic field simulation. The temperature rise of the MR fluid in the annular gap caused by core loss (i.e. eddy current loss and hysteresis loss) and fluid motion is computed to investigate the current-force behavior. A group of impulsive tests was performed for the manufactured MR absorber with step exciting currents. The numerical and experimental results showed good agreement, which validates the effectiveness of the proposed multi-physics FEA model.

Earthquake likelihood model testing

USGS Publications Warehouse

Schorlemmer, D.; Gerstenberger, M.C.; Wiemer, S.; Jackson, D.D.; Rhoades, D.A.

2007-01-01

INTRODUCTIONThe Regional Earthquake Likelihood Models (RELM) project aims to produce and evaluate alternate models of earthquake potential (probability per unit volume, magnitude, and time) for California. Based on differing assumptions, these models are produced to test the validity of their assumptions and to explore which models should be incorporated in seismic hazard and risk evaluation. Tests based on physical and geological criteria are useful but we focus on statistical methods using future earthquake catalog data only. We envision two evaluations: a test of consistency with observed data and a comparison of all pairs of models for relative consistency. Both tests are based on the likelihood method, and both are fully prospective (i.e., the models are not adjusted to fit the test data). To be tested, each model must assign a probability to any possible event within a specified region of space, time, and magnitude. For our tests the models must use a common format: earthquake rates in specified “bins” with location, magnitude, time, and focal mechanism limits.Seismology cannot yet deterministically predict individual earthquakes; however, it should seek the best possible models for forecasting earthquake occurrence. This paper describes the statistical rules of an experiment to examine and test earthquake forecasts. The primary purposes of the tests described below are to evaluate physical models for earthquakes, assure that source models used in seismic hazard and risk studies are consistent with earthquake data, and provide quantitative measures by which models can be assigned weights in a consensus model or be judged as suitable for particular regions.In this paper we develop a statistical method for testing earthquake likelihood models. A companion paper (Schorlemmer and Gerstenberger 2007, this issue) discusses the actual implementation of these tests in the framework of the RELM initiative.Statistical testing of hypotheses is a common task and a wide range of possible testing procedures exist. Jolliffe and Stephenson (2003) present different forecast verifications from atmospheric science, among them likelihood testing of probability forecasts and testing the occurrence of binary events. Testing binary events requires that for each forecasted event, the spatial, temporal and magnitude limits be given. Although major earthquakes can be considered binary events, the models within the RELM project express their forecasts on a spatial grid and in 0.1 magnitude units; thus the results are a distribution of rates over space and magnitude. These forecasts can be tested with likelihood tests.In general, likelihood tests assume a valid null hypothesis against which a given hypothesis is tested. The outcome is either a rejection of the null hypothesis in favor of the test hypothesis or a nonrejection, meaning the test hypothesis cannot outperform the null hypothesis at a given significance level. Within RELM, there is no accepted null hypothesis and thus the likelihood test needs to be expanded to allow comparable testing of equipollent hypotheses.To test models against one another, we require that forecasts are expressed in a standard format: the average rate of earthquake occurrence within pre-specified limits of hypocentral latitude, longitude, depth, magnitude, time period, and focal mechanisms. Focal mechanisms should either be described as the inclination of P-axis, declination of P-axis, and inclination of the T-axis, or as strike, dip, and rake angles. Schorlemmer and Gerstenberger (2007, this issue) designed classes of these parameters such that similar models will be tested against each other. These classes make the forecasts comparable between models. Additionally, we are limited to testing only what is precisely defined and consistently reported in earthquake catalogs. Therefore it is currently not possible to test such information as fault rupture length or area, asperity location, etc. Also, to account for data quality issues, we allow for location and magnitude uncertainties as well as the probability that an event is dependent on another event.As we mentioned above, only models with comparable forecasts can be tested against each other. Our current tests are designed to examine grid-based models. This requires that any fault-based model be adapted to a grid before testing is possible. While this is a limitation of the testing, it is an inherent difficulty in any such comparative testing. Please refer to appendix B for a statistical evaluation of the application of the Poisson hypothesis to fault-based models.The testing suite we present consists of three different tests: L-Test, N-Test, and R-Test. These tests are defined similarily to Kagan and Jackson (1995). The first two tests examine the consistency of the hypotheses with the observations while the last test compares the spatial performances of the models.

An empirical evaluation of the structure of DSM-IV personality disorders in a nationally representative sample: results of confirmatory factor analysis in the National Epidemiologic Survey on Alcohol and Related Conditions Waves 1 and 2.

PubMed

Cox, Brian J; Clara, Ian P; Worobec, Lydia M; Grant, Bridget F

2012-12-01

Individual personality disorders (PD) are grouped into three clusters in the DSM-IV (A, B, and C). There is very little empirical evidence available concerning the validity of this model in the general population. The current study included all 10 of the DSM-IV PD assessed in Wave 1 and Wave 2 of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC). Confirmatory factor analysis was used to evaluate three plausible models of the structure of Axis II personality disorders (the current hierarchical DSM-IV three-factor model in which individual PD are believed to load on their assigned clusters, which in turn load onto a single Axis II factor; a general single-factor model; and three independent factors). Each of these models was tested in both the total and also separately for gender. The higher order DSM-IV model demonstrated good fit to the data on a number of goodness-of-fit indices. The results for this model were very similar across genders. A model of PD based on the current DSM-IV hierarchical conceptualization of a higher order classification scheme received strong empirical support through confirmatory factor analysis using a number of goodness-of-fit indices in a nationally representative sample. Other models involving broad, higher order personality domains such as neuroticism in relation to personality disorders have yet to be tested in epidemiologic surveys and represent an important avenue for future research.

Theory and application of high temperature superconducting eddy current probes for nondestructive evaluation

NASA Astrophysics Data System (ADS)

Claycomb, James Ronald

1998-10-01

Several High-T c Superconducting (HTS) eddy current probes have been developed for applications in electromagnetic nondestructive evaluation (NDE) of conducting materials. The probes utilize high-T c SUperconducting Quantum Interference Device (SQUID) magnetometers to detect the fields produced by the perturbation of induced eddy currents resulting from subsurface flaws. Localized HTS shields are incorporated to selectively screen out environmental electromagnetic interference and enable movement of the instrument in the Earth's magnetic field. High permeability magnetic shields are employed to focus flux into, and thereby increase the eddy current density in the metallic test samples. NDE test results are presented, in which machined flaws in aluminum alloy are detected by probes of different design. A novel current injection technique performing NDE of wires using SQUIDs is also discussed. The HTS and high permeability shields are designed based on analytical and numerical finite element method (FEM) calculations presented here. Superconducting and high permeability magnetic shields are modeled in uniform noise fields and in the presence of dipole fields characteristic of flaw signals. Several shield designs are characterized in terms of (1) their ability to screen out uniform background noise fields; (2) the resultant improvement in signal-to-noise ratio and (3) the extent to which dipole source fields are distorted. An analysis of eddy current induction is then presented for low frequency SQUID NDE. Analytical expressions are developed for the induced eddy currents and resulting magnetic fields produced by excitation sources above conducting plates of varying thickness. The expressions derived here are used to model the SQUID's response to material thinning. An analytical defect model is also developed, taking into account the attenuation of the defect field through the conducting material, as well as the current flow around the edges of the flaw. Time harmonic FEM calculations are then used to model the electromagnetic response of eight probe designs, consisting of an eddy current drive coil coupled to a SQUID surrounded by superconducting and/or high permeability magnetic shielding. Simulations are carried out with the eddy current probes located a finite distance above a conducting surface. Results are quantified in terms of shielding and focus factors for each probe design.

Effects of Combined Hands-on Laboratory and Computer Modeling on Student Learning of Gas Laws: A Quasi-Experimental Study

ERIC Educational Resources Information Center

Liu, Xiufeng

2006-01-01

Based on current theories of chemistry learning, this study intends to test a hypothesis that computer modeling enhanced hands-on chemistry laboratories are more effective than hands-on laboratories or computer modeling laboratories alone in facilitating high school students' understanding of chemistry concepts. Thirty-three high school chemistry…

EPA ALPHA Modeling of a Conventional Mid-Size Car with CVT and Comparable Powertrain Technologies (SAE 2016-01-1141)

EPA Science Inventory

This paper presents the testing and ALPHA modeling of a CVT-equipped 2013 Nissan Altima 2.5S using comparable powertrain technology inputs in the effort to model the current and future U.S. light-duty vehicle fleet approximated using components with comparable levels of performan...

Associating Animations with Concrete Models to Enhance Students' Comprehension of Different Visual Representations in Organic Chemistry

ERIC Educational Resources Information Center

Al-Balushi, Sulaiman M.; Al-Hajri, Sheikha H.

2014-01-01

The purpose of the current study is to explore the impact of associating animations with concrete models on eleventh-grade students' comprehension of different visual representations in organic chemistry. The study used a post-test control group quasi-experimental design. The experimental group (N = 28) used concrete models, submicroscopic…

Using Generalized Additive Models to Analyze Single-Case Designs

ERIC Educational Resources Information Center

Shadish, William; Sullivan, Kristynn

2013-01-01

Many analyses for single-case designs (SCDs)--including nearly all the effect size indicators-- currently assume no trend in the data. Regression and multilevel models allow for trend, but usually test only linear trend and have no principled way of knowing if higher order trends should be represented in the model. This paper shows how Generalized…

Confirmatory evidence for a multidimensional model of racial-ethnic socialization for transracially adoptive families.

PubMed

Langrehr, Kimberly J; Thomas, Anita Jones; Morgan, Sydney K

2016-07-01

The purpose of the current study is to test a recently established model of racial-ethnic socialization (Langrehr, 2014) among 2 samples of White transracially adoptive parents and to assess whether the proposed model functions similarly after accounting for adopted child race. Based on a modified version of the Racial Bias Preparation Scale (Fisher, Wallace, & Fenton, 2000), confirmatory factor analysis was used to test the 3-factor model (i.e., Prejudice Awareness, Racial-Ethnic Pride, and Egalitarianism) among 172 White transracially adoptive parents with Asian children (Mage = 45.72) and 140 White transracially adoptive parents with Black children (Mage = 42.62). In addition, multigroup invariance testing was used to assess whether the proposed model functioned similarly across the 2 groups of parents. Results indicate that the proposed 3-factor model demonstrated partial measurement invariance such that the subconstruct of Egalitarianism functioned similarly across groups, whereas Racial-Ethnic Pride and Prejudice Awareness were deemed noninvariant. Findings are intended to help expand the concept of racial-ethnic socialization for transracially adoptive families and address the degree to which current research on racial-ethnic socialization can be applied to different transracially adoptive families. Results are intended to highlight ways that various social-cultural dimensions of family can culminate into different socialization experiences. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Plant water potential improves prediction of empirical stomatal models.

PubMed

Anderegg, William R L; Wolf, Adam; Arango-Velez, Adriana; Choat, Brendan; Chmura, Daniel J; Jansen, Steven; Kolb, Thomas; Li, Shan; Meinzer, Frederick; Pita, Pilar; Resco de Dios, Víctor; Sperry, John S; Wolfe, Brett T; Pacala, Stephen

2017-01-01

Climate change is expected to lead to increases in drought frequency and severity, with deleterious effects on many ecosystems. Stomatal responses to changing environmental conditions form the backbone of all ecosystem models, but are based on empirical relationships and are not well-tested during drought conditions. Here, we use a dataset of 34 woody plant species spanning global forest biomes to examine the effect of leaf water potential on stomatal conductance and test the predictive accuracy of three major stomatal models and a recently proposed model. We find that current leaf-level empirical models have consistent biases of over-prediction of stomatal conductance during dry conditions, particularly at low soil water potentials. Furthermore, the recently proposed stomatal conductance model yields increases in predictive capability compared to current models, and with particular improvement during drought conditions. Our results reveal that including stomatal sensitivity to declining water potential and consequent impairment of plant water transport will improve predictions during drought conditions and show that many biomes contain a diversity of plant stomatal strategies that range from risky to conservative stomatal regulation during water stress. Such improvements in stomatal simulation are greatly needed to help unravel and predict the response of ecosystems to future climate extremes.

Drought forecasting in Luanhe River basin involving climatic indices

NASA Astrophysics Data System (ADS)

Ren, Weinan; Wang, Yixuan; Li, Jianzhu; Feng, Ping; Smith, Ronald J.

2017-11-01

Drought is regarded as one of the most severe natural disasters globally. This is especially the case in Tianjin City, Northern China, where drought can affect economic development and people's livelihoods. Drought forecasting, the basis of drought management, is an important mitigation strategy. In this paper, we evolve a probabilistic forecasting model, which forecasts transition probabilities from a current Standardized Precipitation Index (SPI) value to a future SPI class, based on conditional distribution of multivariate normal distribution to involve two large-scale climatic indices at the same time, and apply the forecasting model to 26 rain gauges in the Luanhe River basin in North China. The establishment of the model and the derivation of the SPI are based on the hypothesis of aggregated monthly precipitation that is normally distributed. Pearson correlation and Shapiro-Wilk normality tests are used to select appropriate SPI time scale and large-scale climatic indices. Findings indicated that longer-term aggregated monthly precipitation, in general, was more likely to be considered normally distributed and forecasting models should be applied to each gauge, respectively, rather than to the whole basin. Taking Liying Gauge as an example, we illustrate the impact of the SPI time scale and lead time on transition probabilities. Then, the controlled climatic indices of every gauge are selected by Pearson correlation test and the multivariate normality of SPI, corresponding climatic indices for current month and SPI 1, 2, and 3 months later are demonstrated using Shapiro-Wilk normality test. Subsequently, we illustrate the impact of large-scale oceanic-atmospheric circulation patterns on transition probabilities. Finally, we use a score method to evaluate and compare the performance of the three forecasting models and compare them with two traditional models which forecast transition probabilities from a current to a future SPI class. The results show that the three proposed models outperform the two traditional models and involving large-scale climatic indices can improve the forecasting accuracy.

Establishment of a VISAR Measurement System for Material Model Validation in DSTO

DTIC Science & Technology

2013-02-01

advancements published in the works by L.M. Baker, E.R. Hollenbach and W.F. Hemsing [1-3] and results in the user-friendly interface and configuration of the...VISAR system [4] used in the current work . VISAR tests are among the mandatory instrumentation techniques when validating material models and...The present work reports on preliminary tests using the recently commissioned DSTO VISAR system, providing an assessment of the experimental set-up

Development of a preprototype trace contaminant control system. [for space stations

NASA Technical Reports Server (NTRS)

1977-01-01

The steady state contaminant load model based on shuttle equipment and material test programs, and on the current space station studies was revised. An emergency upset contaminant load model based on anticipated emergency upsets that could occur in an operational space station was defined. Control methods for the contaminants generated by the emergency upsets were established by test. Preliminary designs of both steady state and emergency contaminant control systems for the space station application are presented.

Design of Training Systems (DOTS) Project: Test and Evaluation of Phase II Models

DTIC Science & Technology

1976-04-01

when the process being modeled is very much dependent upon human resoarces, precise requirement formulas are usually V unavailable. In this...mixed integer formulation options. The SGRR, in a sense, is an automiation of what is cu~rrently beinig donec men~tall y by instructors and trai ninrg nv...test and evaluation (T&E); information concerning CNETS LCDR R. J. Biersner Human Factors Analysis, N-214 AV 922-1392 CNTECHTRA CDR J. D. Davis

Preliminary Multivariable Cost Model for Space Telescopes

NASA Technical Reports Server (NTRS)

Stahl, H. Philip

2010-01-01

Parametric cost models are routinely used to plan missions, compare concepts and justify technology investments. Previously, the authors published two single variable cost models based on 19 flight missions. The current paper presents the development of a multi-variable space telescopes cost model. The validity of previously published models are tested. Cost estimating relationships which are and are not significant cost drivers are identified. And, interrelationships between variables are explored

In Vitro, In Vivo and Post Explantation Testing of Glucose-Detecting Biosensors: Current Methods and Recommendations

PubMed Central

Koschwanez, Heidi E.; Reichert, W. Monty

2007-01-01

To date, there have been a number of cases where glucose sensors have performed well over long periods of implantation; however, it remains difficult to predict whether a given sensor will perform reliably, will exhibit gradual degradation of performance, or will fail outright soon after implantation. Typically, the literature emphasizes the sensor that performed well, while only briefly (if at all) mentioning the failed devices. This leaves open the question of whether current sensor designs are adequate for the hostile in vivo environment, and whether these sensors have been assessed by the proper regimen of testing protocols. This paper reviews the current in vitro and in vivo testing procedures used to evaluate the functionality and biocompatibility of implantable glucose sensors. An overview of the standards and regulatory bodies that govern biomaterials and end-product device testing precedes a discussion of up-to-date invasive and non-invasive technologies for diabetes management. Analysis of current in vitro, in vivo, and then post implantation testing is presented. Given the underlying assumption that the success of the sensor in vivo foreshadows the long-term reliability of the sensor in the human body, the relative merits of these testing methods are evaluated with respect to how representative they are of human models. PMID:17524479

Numerical Calculation of the Spectrum of the Severe (1%) Lighting Current and Its First Derivative

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, C G; Ong, M M; Perkins, M P

2010-02-12

Recently, the direct-strike lighting environment for the stockpile-to-target sequence was updated [1]. In [1], the severe (1%) lightning current waveforms for first and subsequent return strokes are defined based on Heidler's waveform. This report presents numerical calculations of the spectra of those 1% lightning current waveforms and their first derivatives. First, the 1% lightning current models are repeated here for convenience. Then, the numerical method for calculating the spectra is presented and tested. The test uses a double-exponential waveform and its first derivative, which we fit to the previous 1% direct-strike lighting environment from [2]. Finally, the resulting spectra aremore » given and are compared with those of the double-exponential waveform and its first derivative.« less

PLEMT: A NOVEL PSEUDOLIKELIHOOD BASED EM TEST FOR HOMOGENEITY IN GENERALIZED EXPONENTIAL TILT MIXTURE MODELS.

PubMed

Hong, Chuan; Chen, Yong; Ning, Yang; Wang, Shuang; Wu, Hao; Carroll, Raymond J

2017-01-01

Motivated by analyses of DNA methylation data, we propose a semiparametric mixture model, namely the generalized exponential tilt mixture model, to account for heterogeneity between differentially methylated and non-differentially methylated subjects in the cancer group, and capture the differences in higher order moments (e.g. mean and variance) between subjects in cancer and normal groups. A pairwise pseudolikelihood is constructed to eliminate the unknown nuisance function. To circumvent boundary and non-identifiability problems as in parametric mixture models, we modify the pseudolikelihood by adding a penalty function. In addition, the test with simple asymptotic distribution has computational advantages compared with permutation-based test for high-dimensional genetic or epigenetic data. We propose a pseudolikelihood based expectation-maximization test, and show the proposed test follows a simple chi-squared limiting distribution. Simulation studies show that the proposed test controls Type I errors well and has better power compared to several current tests. In particular, the proposed test outperforms the commonly used tests under all simulation settings considered, especially when there are variance differences between two groups. The proposed test is applied to a real data set to identify differentially methylated sites between ovarian cancer subjects and normal subjects.

Testing and validating environmental models

USGS Publications Warehouse

Kirchner, J.W.; Hooper, R.P.; Kendall, C.; Neal, C.; Leavesley, G.

1996-01-01

Generally accepted standards for testing and validating ecosystem models would benefit both modellers and model users. Universally applicable test procedures are difficult to prescribe, given the diversity of modelling approaches and the many uses for models. However, the generally accepted scientific principles of documentation and disclosure provide a useful framework for devising general standards for model evaluation. Adequately documenting model tests requires explicit performance criteria, and explicit benchmarks against which model performance is compared. A model's validity, reliability, and accuracy can be most meaningfully judged by explicit comparison against the available alternatives. In contrast, current practice is often characterized by vague, subjective claims that model predictions show 'acceptable' agreement with data; such claims provide little basis for choosing among alternative models. Strict model tests (those that invalid models are unlikely to pass) are the only ones capable of convincing rational skeptics that a model is probably valid. However, 'false positive' rates as low as 10% can substantially erode the power of validation tests, making them insufficiently strict to convince rational skeptics. Validation tests are often undermined by excessive parameter calibration and overuse of ad hoc model features. Tests are often also divorced from the conditions under which a model will be used, particularly when it is designed to forecast beyond the range of historical experience. In such situations, data from laboratory and field manipulation experiments can provide particularly effective tests, because one can create experimental conditions quite different from historical data, and because experimental data can provide a more precisely defined 'target' for the model to hit. We present a simple demonstration showing that the two most common methods for comparing model predictions to environmental time series (plotting model time series against data time series, and plotting predicted versus observed values) have little diagnostic power. We propose that it may be more useful to statistically extract the relationships of primary interest from the time series, and test the model directly against them.

Quantitative, steady-state properties of Catania's computational model of the operant reserve.

PubMed

Berg, John P; McDowell, J J

2011-05-01

Catania (2005) found that a computational model of the operant reserve (Skinner, 1938) produced realistic behavior in initial, exploratory analyses. Although Catania's operant reserve computational model demonstrated potential to simulate varied behavioral phenomena, the model was not systematically tested. The current project replicated and extended the Catania model, clarified its capabilities through systematic testing, and determined the extent to which it produces behavior corresponding to matching theory. Significant departures from both classic and modern matching theory were found in behavior generated by the model across all conditions. The results suggest that a simple, dynamic operant model of the reflex reserve does not simulate realistic steady state behavior. Copyright © 2011 Elsevier B.V. All rights reserved.

The modelling of an SF6 arc in a supersonic nozzle: II. Current zero behaviour of the nozzle arc

NASA Astrophysics Data System (ADS)

Zhang, Q.; Liu, J.; Yan, J. D.; Fang, M. T. C.

2016-08-01

The present work (part II) forms the second part of an investigation into the behaviour of SF6 nozzle arc. It is concerned with the aerodynamic and electrical behaviour of a transient nozzle arc under a current ramp specified by a rate of current decay (di/dt) before current zero and a voltage ramp (dV/dt) after current zero. The five flow models used in part I [1] for cold gas flow and DC nozzle arcs have been applied to study the transient arc at three stagnation pressures (P 0) and two values of di/dt for the current ramp, representing a wide range of arcing conditions. An analysis of the physical mechanisms encompassed in each flow model is given with an emphasis on the adequacy of a particular model in describing the rapidly varying arc around current zero. The critical rate of rise of recovery voltage (RRRV) is found computationally and compared with test results of Benenson et al [2]. For transient nozzle arcs, the RRRV is proportional to the square of P 0, rather than to the square root of P 0 for DC nozzle arcs. The physical mechanisms responsible for the strong dependence of RRRV on P 0 have been investigated. The relative merits of the flow models employed are discussed.

A Comparative Test of Work-Family Conflict Models and Critical Examination of Work-Family Linkages

ERIC Educational Resources Information Center

Michel, Jesse S.; Mitchelson, Jacqueline K.; Kotrba, Lindsey M.; LeBreton, James M.; Baltes, Boris B.

2009-01-01

This paper is a comprehensive meta-analysis of over 20 years of work-family conflict research. A series of path analyses were conducted to compare and contrast existing work-family conflict models, as well as a new model we developed which integrates and synthesizes current work-family theory and research. This new model accounted for 40% of the…

Development of the GPM Observatory Thermal Vacuum Test Model

NASA Technical Reports Server (NTRS)

Yang, Kan; Peabody, Hume

2012-01-01

A software-based thermal modeling process was documented for generating the thermal panel settings necessary to simulate worst-case on-orbit flight environments in an observatory-level thermal vacuum test setup. The method for creating such a thermal model involved four major steps: (1) determining the major thermal zones for test as indicated by the major dissipating components on the spacecraft, then mapping the major heat flows between these components; (2) finding the flight equivalent sink temperatures for these test thermal zones; (3) determining the thermal test ground support equipment (GSE) design and initial thermal panel settings based on the equivalent sink temperatures; and (4) adjusting the panel settings in the test model to match heat flows and temperatures with the flight model. The observatory test thermal model developed from this process allows quick predictions of the performance of the thermal vacuum test design. In this work, the method described above was applied to the Global Precipitation Measurement (GPM) core observatory spacecraft, a joint project between NASA and the Japanese Aerospace Exploration Agency (JAXA) which is currently being integrated at NASA Goddard Space Flight Center for launch in Early 2014. From preliminary results, the thermal test model generated from this process shows that the heat flows and temperatures match fairly well with the flight thermal model, indicating that the test model can simulate fairly accurately the conditions on-orbit. However, further analysis is needed to determine the best test configuration possible to validate the GPM thermal design before the start of environmental testing later this year. Also, while this analysis method has been applied solely to GPM, it should be emphasized that the same process can be applied to any mission to develop an effective test setup and panel settings which accurately simulate on-orbit thermal environments.

Modelling high frequency phenomena in the rotor of induction motors under no-load test conditions

NASA Astrophysics Data System (ADS)

Boglietti, Aldo; Bottauscio, Oriano; Chiampi, Mario; Lazzari, Mario

2003-01-01

The paper aims to deep the electromagnetic phenomena in the rotor of induction motors produced during the no-load test by the high-order harmonics of the spatial distribution of magnetic flux. The analysis is carried out by a flux driven finite element procedure, which can take into account the hysteresis of magnetic material, the induced currents in rotor cage and the eddy currents in the laminations. The computed results, including losses and local waveforms of electrical and magnetic quantities, are finally discussed.

Space Shuttle Main Engine Low Pressure Oxidizer Turbo-Pump Inducer Dynamic Environment Characterization through Water Model and Hot-Fire Testing

NASA Technical Reports Server (NTRS)

Arellano, Patrick; Patton, Marc; Schwartz, Alan; Stanton, David

2006-01-01

The Low Pressure Oxidizer Turbopump (LPOTP) inducer on the Block II configuration Space Shuttle Main Engine (SSME) experienced blade leading edge ripples during hot firing. This undesirable condition led to a minor redesign of the inducer blades. This resulted in the need to evaluate the performance and the dynamic environment of the redesign, relative to the current configuration, as part of the design acceptance process. Sub-scale water model tests of the two inducer configurations were performed, with emphasis on the dynamic environment due to cavitation induced vibrations. Water model tests were performed over a wide range of inlet flow coefficient and pressure conditions, representative of the scaled operating envelope of the Block II SSME, both in flight and in ground hot-fire tests, including all power levels. The water test hardware, facility set-up, type and placement of instrumentation, the scope of the test program, specific test objectives, data evaluation process and water test results that characterize and compare the two SSME LPOTP inducers are discussed. In addition, dynamic characteristics of the two water models were compared to hot fire data from specially instrumented ground tests. In general, good agreement between the water model and hot fire data was found, which confirms the value of water model testing for dynamic characterization of rocket engine turbomachinery.

Improvement of Olfactory Function With High Frequency Non-invasive Auricular Electrostimulation in Healthy Humans

PubMed Central

Maharjan, Ashim; Wang, Eunice; Peng, Mei; Cakmak, Yusuf O.

2018-01-01

In past literature on animal models, invasive vagal nerve stimulation using high frequencies has shown to be effective at modulating the activity of the olfactory bulb (OB). Recent advances in invasive vagal nerve stimulation in humans, despite previous findings in animal models, used low frequency stimulation and found no effect on the olfactory functioning. The present article aimed to test potential effects of non-invasive, high and low frequency vagal nerve stimulation in humans, with supplementary exploration of the orbitofrontal cortex using near-infrared spectroscopy (NIRS). Healthy, male adult participants (n = 18) performed two olfactory tests [odor threshold test (OTT) and supra-threshold test (STT)] before and after receiving high-, low frequency vagal nerve stimulation and placebo (no stimulation). Participant's olfactory functioning was monitored using NIRS, and assessed with two behavioral olfactory tests. NIRS data of separate stimulation parameters were statistically analyzed using repeated-measures ANOVA across different stages. Data from olfactory tests were analyzed using paired parametric and non-parametric statistical tests. Only high frequency, non-invasive vagal nerve stimulation was able to positively modulate the performance of the healthy participants in the STT (p = 0.021, Wilcoxon sign-ranked test), with significant differences in NIRS (p = 0.014, post-hoc with Bonferroni correction) recordings of the right hemispheric, orbitofrontal cortex. The results from the current article implore further exploration of the neurocircuitry involved under vagal nerve stimulation and the effects of non-invasive, high frequency, vagal nerve stimulation toward olfactory dysfunction which showcase in Parkinson's and Alzheimer's Diseases. Despite the sufficient effect size (moderate effect, correlation coefficient (r): 0.39 for the STT) of the current study, future research should replicate the current findings with a larger cohort. PMID:29740266

Improvement of Olfactory Function With High Frequency Non-invasive Auricular Electrostimulation in Healthy Humans.

PubMed

Maharjan, Ashim; Wang, Eunice; Peng, Mei; Cakmak, Yusuf O

2018-01-01

In past literature on animal models, invasive vagal nerve stimulation using high frequencies has shown to be effective at modulating the activity of the olfactory bulb (OB). Recent advances in invasive vagal nerve stimulation in humans, despite previous findings in animal models, used low frequency stimulation and found no effect on the olfactory functioning. The present article aimed to test potential effects of non-invasive, high and low frequency vagal nerve stimulation in humans, with supplementary exploration of the orbitofrontal cortex using near-infrared spectroscopy (NIRS). Healthy, male adult participants ( n = 18) performed two olfactory tests [odor threshold test (OTT) and supra-threshold test (STT)] before and after receiving high-, low frequency vagal nerve stimulation and placebo (no stimulation). Participant's olfactory functioning was monitored using NIRS, and assessed with two behavioral olfactory tests. NIRS data of separate stimulation parameters were statistically analyzed using repeated-measures ANOVA across different stages. Data from olfactory tests were analyzed using paired parametric and non-parametric statistical tests. Only high frequency, non-invasive vagal nerve stimulation was able to positively modulate the performance of the healthy participants in the STT ( p = 0.021, Wilcoxon sign-ranked test), with significant differences in NIRS ( p = 0.014, post-hoc with Bonferroni correction ) recordings of the right hemispheric, orbitofrontal cortex. The results from the current article implore further exploration of the neurocircuitry involved under vagal nerve stimulation and the effects of non-invasive, high frequency, vagal nerve stimulation toward olfactory dysfunction which showcase in Parkinson's and Alzheimer's Diseases. Despite the sufficient effect size (moderate effect, correlation coefficient (r): 0.39 for the STT) of the current study, future research should replicate the current findings with a larger cohort.

A human factors approach towards the design of a new glovebox glove for Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oka, Jude M.

Present day glovebox gloves at Los Alamos National Laboratory (LANL) are underdeveloped and ergonomically inaccurate. This problem results in numerous sprain and strain injuries every year for employees who perform glovebox work. In addition to injuries, using the current glovebox glove design also contributes to breaches and contamination. The current glove used today at LANL has several problems: (1) The length of the fingers is incorrect, (2) the web spacing between the fingers is nonexistent, (3) the angles between each digit on the finger are incorrect, (4) the thumb is placed inaccurately, and (5) the length of the hand ismore » incorrect. These problems present a need to correct the current glove design to decrease the risk of injuries, breaches, and contamination. Anthropometrics were researched to help find the best range of hand measurements to fix the current glove design. Anthropometrics is the measure of the human physical variation. Anthropometrics for this study were gathered from the American National Survey (ANSUR) data that was conducted by the U.S Army in 1988. The current glovebox glove uses anthropometrics from the 95th to 105th percentile range which is too large so the new gloves are going to implement data from a smaller range of percentile groups. The 105th percentile range represents measurements that exceed the human population but are needed to fit certain circumstance such as wearing several under gloves within the glovebox gloves. Anthropometrics used in this study include: 105th percentile measurements for joint circumference which was unchanged because the room for under gloves plus ease of hand insertion and extraction is needed, 80th percentile measurements for crotch length to allow workers to reach the web spacing in the glove, 20th percentile measurements for finger length to allow workers to reach the end of the glove, standard 10.5cm hand breadth to allow more room to accommodate under gloves, 45 degrees abduction angle for the thumb for better positioning, 45 degrees extension angle for the thumb for better positioning, and various angles for the other fingers to allow a more relaxed and natural fit. 3D modeling was used to implement the anthropometric data listed above onto an existing scanned solid model of a human hand. SolidWorks 2010 3-D modeling package was utilized to manipulate the hand model to represent the anthropometric data researched. The anthropometrics and modifications were reviewed by the University of New Mexico Department of Orthopedics hand surgeons. After all modifications and reviews were completed the model was printed out using stereolithography. The printed out model of the hand was used as a mold to create a prototype glovebox glove. The new mold was taken to Piercan USA to produce a 20mil Polyurethane/Hypalon glovebox glove. The Minnesota Dexterity test and Purdue Pegboard test were used to measure the dexterity of the prototype glovebox glove against a current 15 mil Hypalon LANL glovebox glove. Using the data from the tests a student t test was used to determine if there was a significant difference between the current hypalon glove results and the new prototype glove results. With a 95% confidence level the prototype showed to have a significantly lower mean difference from the current hypalon glovebox glove with the Minnesota Dexterity test. With a 95% confidence level the prototype showed to have a significantly higher mean difference from the current hypalon glovebox glove with the Purdue Pegboard test. A p value method was also performed to confirm the results of the student t test. A survey was also given to glovebox workers to determine if they preferred the new design. The best reaction from glovebox workers was the new thumb position, 73.2% of the sample population agreed with the new thumb position. Developing a new glovebox glove will improve the ergonomics of the hand for work performed, decrease exposure time, decreasing risk of breaching, increasing productivity, reducing injuries, and improving work performance. In the future the new glovebox glove can also be implemented in other research fields such as: pharmaceutical research and development, semiconducting industry, biohazard industry, and other laboratories conducting nuclear research and development.« less

On the coverage of the pMSSM by simplified model results

NASA Astrophysics Data System (ADS)

Ambrogi, Federico; Kraml, Sabine; Kulkarni, Suchita; Laa, Ursula; Lessa, Andre; Waltenberger, Wolfgang

2018-03-01

We investigate to which extent the SUSY search results published by ATLAS and CMS in the context of simplified models actually cover the more realistic scenarios of a full model. Concretely, we work within the phenomenological MSSM (pMSSM) with 19 free parameters and compare the constraints obtained from SModelS v1.1.1 with those from the ATLAS pMSSM study in arXiv:1508.06608. We find that about 40-45% of the points excluded by ATLAS escape the currently available simplified model constraints. For these points we identify the most relevant topologies which are not tested by the current simplified model results. In particular, we find that topologies with asymmetric branches, including 3-jet signatures from gluino-squark associated production, could be important for improving the current constraining power of simplified models results. Furthermore, for a better coverage of light stops and sbottoms, constraints for decays via heavier neutralinos and charginos, which subsequently decay visibly to the lightest neutralino are also needed.

Analytical and Experimental Assessment of Seismic Vulnerability of Beam-Column Joints without Transverse Reinforcement in Concrete Buildings

NASA Astrophysics Data System (ADS)

Hassan, Wael Mohammed

Beam-column joints in concrete buildings are key components to ensure structural integrity of building performance under seismic loading. Earthquake reconnaissance has reported the substantial damage that can result from inadequate beam-column joints. In some cases, failure of older-type corner joints appears to have led to building collapse. Since the 1960s, many advances have been made to improve seismic performance of building components, including beam-column joints. New design and detailing approaches are expected to produce new construction that will perform satisfactorily during strong earthquake shaking. Much less attention has been focused on beam-column joints of older construction that may be seismically vulnerable. Concrete buildings constructed prior to developing details for ductility in the 1970s normally lack joint transverse reinforcement. The available literature concerning the performance of such joints is relatively limited, but concerns about performance exist. The current study aimed to improve understanding and assessment of seismic performance of unconfined exterior and corner beam-column joints in existing buildings. An extensive literature survey was performed, leading to development of a database of about a hundred tests. Study of the data enabled identification of the most important parameters and the effect of each parameter on the seismic performance. The available analytical models and guidelines for strength and deformability assessment of unconfined joints were surveyed and evaluated. In particular, The ASCE 41 existing building document proved to be substantially conservative in joint shear strength estimation. Upon identifying deficiencies in these models, two new joint shear strength models, a bond capacity model, and two axial capacity models designed and tailored specifically for unconfined beam-column joints were developed. The proposed models strongly correlated with previous test results. In the laboratory testing phase of the current study, four full-scale corner beam-column joint subassemblies, with slab included, were designed, built, instrumented, tested, and analyzed. The specimens were tested under unidirectional and bidirectional displacement-controlled quasi-static loading that incorporated varying axial loads that simulated overturning seismic moment effects. The axial loads varied between tension and high compression loads reaching about 50% of the column axial capacity. The test parameters were axial load level, loading history, joint aspect ratio, and beam reinforcement ratio. The test results proved that high axial load increases joint shear strength and decreases the deformability of joints failing in pure shear failure mode without beam yielding. On the contrary, high axial load did not affect the strength of joints failing in shear after significant beam yielding; however, it substantially increased their displacement ductility. Joint aspect ratio proved to be instrumental in deciding joint shear strength; that is the deeper the joint the lower the shear strength. Bidirectional loading reduced the apparent strength of the joint in the uniaxial principal axes. However, circular shear strength interaction is an appropriate approximation to predict the biaxial strength. The developed shear strength models predicted successfully the strength of test specimens. Based on the literature database investigation, the shear and axial capacity models developed and the test results of the current study, an analytical finite element component model based on a proposed joint shear stress-rotation backbone constitutive curve was developed to represent the behavior of unconfined beam-column joints in computer numerical simulations of concrete frame buildings. The proposed finite element model included the effect of axial load, mode of joint failure, joint aspect ratio and axial capacity of joint. The proposed backbone curve along with the developed joint element exhibited high accuracy in simulating the test response of the current test specimens as well as previous test joints. Finally, a parametric study was conducted to assess the axial failure vulnerability of unconfined beam-column joints based on the developed shear and axial capacity models. This parametric study compared the axial failure potential of unconfined beam-column joint with that of shear critical columns to provide a preliminary insight into the axial collapse vulnerability of older-type buildings during intense ground shaking.

Airframe noise prediction evaluation

NASA Technical Reports Server (NTRS)

Yamamoto, Kingo J.; Donelson, Michael J.; Huang, Shumei C.; Joshi, Mahendra C.

1995-01-01

The objective of this study is to evaluate the accuracy and adequacy of current airframe noise prediction methods using available airframe noise measurements from tests of a narrow body transport (DC-9) and a wide body transport (DC-10) in addition to scale model test data. General features of the airframe noise from these aircraft and models are outlined. The results of the assessment of two airframe prediction methods, Fink's and Munson's methods, against flight test data of these aircraft and scale model wind tunnel test data are presented. These methods were extensively evaluated against measured data from several configurations including clean, slat deployed, landing gear-deployed, flap deployed, and landing configurations of both DC-9 and DC-10. They were also assessed against a limited number of configurations of scale models. The evaluation was conducted in terms of overall sound pressure level (OASPL), tone corrected perceived noise level (PNLT), and one-third-octave band sound pressure level (SPL).

Use of the binomial distribution to predict impairment: application in a nonclinical sample.

PubMed

Axelrod, Bradley N; Wall, Jacqueline R; Estes, Bradley W

2008-01-01

A mathematical model based on the binomial theory was developed to illustrate when abnormal score variations occur by chance in a multitest battery (Ingraham & Aiken, 1996). It has been successfully used as a comparison for obtained test scores in clinical samples, but not in nonclinical samples. In the current study, this model has been applied to demographically corrected scores on the Halstead-Reitan Neuropsychological Test Battery, obtained from a sample of 94 nonclinical college students. Results found that 15% of the sample had impairments suggested by the Halstead Impairment Index, using criteria established by Reitan and Wolfson (1993). In addition, one-half of the sample obtained impaired scores on one or two tests. These results were compared to that predicted by the binomial model and found to be consistent. The model therefore serves as a useful resource for clinicians considering the probability of impaired test performance.

Cable testing for Fermilab's high field magnets using small racetrack coils

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feher, S.; Ambrosio, G.; Andreev, N.

As part of the High Field Magnet program at Fermilab simple magnets have been designed utilizing small racetrack coils based on a sound mechanical structure and bladder technique developed by LBNL. Two of these magnets have been built in order to test Nb{sub 3}Sn cables used in cos-theta dipole models. The powder-in-tube strand based cable exhibited excellent performance. It reached its critical current limit within 14 quenches. Modified jelly roll strand based cable performance was limited by magnetic instabilities at low fields as previously tested dipole models which used similar cable.

Design and Test of Fan/Nacelle Models Quiet High-Speed Fan

NASA Technical Reports Server (NTRS)

Miller, Christopher J. (Technical Monitor); Weir, Donald

2003-01-01

The Quiet High-Speed Fan program is a cooperative effort between Honeywell Engines & Systems (formerly AlliedSignal Engines & Systems) and the NASA Glenn Research Center. Engines & Systems has designed an advanced high-speed fan that will be tested on the Ultra High Bypass Propulsion Simulator in the NASA Glenn 9 x 15 foot wind tunnel, currently scheduled for the second quarter of 2000. An Engines & Systems modern fan design will be used as a baseline. A nacelle model is provided that is characteristic of a typical, modern regional aircraft nacelle and meets all of the program test objectives.

Teledyne Energy Systems, Inc., Proton Exchange Member (PEM) Fuel Cell Engineering Model Powerplant. Test Report: Initial Benchmark Tests in the Original Orientation

NASA Technical Reports Server (NTRS)

Loyselle, Patricia; Prokopius, Kevin

2011-01-01

Proton Exchange Membrane (PEM) fuel cell technology is the leading candidate to replace the alkaline fuel cell technology, currently used on the Shuttle, for future space missions. During a 5-yr development program, a PEM fuel cell powerplant was developed. This report details the initial performance evaluation test results of the powerplant.

A Discrete Latent State Approach to Diagnostic Testing. Final Report on Contract Number N00014-81-K-0564.

ERIC Educational Resources Information Center

Paulson, James A.

This paper reports on a project which has developed the general latent class model as a framework for representation of item responses. This framework can be used to represent data in applications such as mastery tests and other kinds of achievement tests, where there is reason to believe that current foundations are deficient. Methods of…

Physics through the 1990s: Gravitation, cosmology and cosmic-ray physics

NASA Technical Reports Server (NTRS)

1986-01-01

The volume contains recommendations for space-and ground-based programs in gravitational physics, cosmology, and cosmic-ray physics. The section on gravitation examines current and planned experimental tests of general relativity; the theory behind, and search for, gravitational waves, including sensitive laser-interferometric tests and other observations; and advances in gravitation theory (for example, incorporating quantum effects). The section on cosmology deals with the big-bang model, the standard model from elementary-particle theory, the inflationary model of the Universe. Computational needs are presented for both gravitation and cosmology. Finally, cosmic-ray physics theory (nucleosynthesis, acceleration models, high-energy physics) and experiment (ground and spaceborne detectors) are discussed.

Estimation of electric fields and current from ground-based magnetometer data

NASA Technical Reports Server (NTRS)

Kamide, Y.; Richmond, A. D.

1984-01-01

Recent advances in numerical algorithms for estimating ionospheric electric fields and currents from groundbased magnetometer data are reviewed and evaluated. Tests of the adequacy of one such algorithm in reproducing large-scale patterns of electrodynamic parameters in the high-latitude ionosphere have yielded generally positive results, at least for some simple cases. Some encouraging advances in producing realistic conductivity models, which are a critical input, are pointed out. When the algorithms are applied to extensive data sets, such as the ones from meridian chain magnetometer networks during the IMS, together with refined conductivity models, unique information on instantaneous electric field and current patterns can be obtained. Examples of electric potentials, ionospheric currents, field-aligned currents, and Joule heating distributions derived from ground magnetic data are presented. Possible directions for future improvements are also pointed out.

Thermal barrier coatings for aircraft engines: History and directions

NASA Technical Reports Server (NTRS)

Miller, R. A.

1995-01-01

Thin thermal barrier coatings for protecting aircraft turbine section airfoils are examined. The discussion focuses on those advances that led first to their use for component life extension and more recently as an integral part of airfoil design. It is noted that development has been driven by laboratory rig and furnace testing corroborated by engine testing and engine field experience. The technology has also been supported by performance modeling to demonstrate benefits and life modeling for mission analysis. Factors which have led to the selection of the current state-of-the-art plasma sprayed and physical vapor deposited zirconia-yttria/MCrAlY TBC's is emphasized in addition to observations fundamentally related to their behavior. Current directions in research into thermal barrier coatings and recent progress at NASA is also noted.

The Stockholm-3 (STHLM3) Model can Improve Prostate Cancer Diagnostics in Men Aged 50-69 yr Compared with Current Prostate Cancer Testing.

PubMed

Eklund, Martin; Nordström, Tobias; Aly, Markus; Adolfsson, Jan; Wiklund, Peter; Brandberg, Yvonne; Thompson, James; Wiklund, Fredrik; Lindberg, Johan; Presti, Joseph C; StLezin, Mark; Clements, Mark; Egevad, Lars; Grönberg, Henrik

2016-11-23

Prostate cancer screening is associated with low specificity, unnecessary biopsies, and overdiagnosis. We have previously shown that the Stockholm-3 model (S3M) can reduce biopsies compared with using prostate-specific antigen (PSA) ≥3ng/ml as an indication for biopsy. Urologists in today's current prostate cancer testing (CPT) have access to numerous variables in addition to PSA (eg, age, ethnicity, family history, free PSA, PSA velocity, digital rectal examination, and prostate volume) to support biopsy decisions. We estimated the number of prostate cancers diagnosed and prostate biopsies performed if S3M replaced CPT in Stockholm, Sweden, by comparing biopsy results in 56 282 men who underwent PSA testing according to CPT in Stockholm in 2011 with the 47 688 men enrolled in the STHLM3 validation cohort 2012-2015. With the same sensitivity as CPT to diagnose Gleason score ≥7 prostate cancer, S3M was estimated to reduce the number of men biopsied by 53% (95% confidence interval [CI]: 41-65%), avoid 76% (95% CI: 67-81%) of negative biopsies, and reduce Gleason score 6 cancers by 23% (95% CI: 6-40%). S3M has the potential to improve prostate cancer diagnostics by better selecting men with high risk of GS ≥7 prostate cancer. We modeled the effect the Stockholm-3 model would have on prostate cancer diagnostics if it replaced current clinical practice. We found that Stockholm-3 model may substantially reduce the number of biopsies, while maintaining the same sensitivity to diagnose clinically significant prostate cancer. Copyright © 2016. Published by Elsevier B.V.

M Current-Based Therapies for Nerve Agent Seizures

DTIC Science & Technology

2012-07-01

2012.235820. Third goal was to test whether drugs that open M channels wouterminate status epilepticus induced by an organophosphate and cholinergic...agonist (Li/Pilocarpine). Two modelof organophasphate-induced seizures were characterized and published: Characterization of status epilepticus induced...terminates refractory status epilepticus in two models. . 15. SUBJECT TERMS- Seizures, status epilepticus Cholinergic, M Current, Synaptoic

A model of the endogenous glucose balance incorporating the characteristics of glucose transporters.

PubMed

Arleth, T; Andreassen, S; Federici, M O; Benedetti, M M

2000-07-01

This paper describes the development and preliminary test of a model of the endogenous glucose balance that incorporates the characteristics of the glucose transporters GLUT1, GLUT3 and GLUT4. In the modeling process the model is parameterized with nine parameters that are subsequently estimated from data in the literature on the hepatic- and endogenous- balances at various combinations of blood glucose and insulin levels. The ability of the resulting endogenous balance to fit blood glucose measured from patients was tested on 20 patients. The fit obtained with this model compared favorably with the fit obtained with the endogenous balance currently incorporated in the DIAS system.

The development and evaluation of a hydrological seasonal forecast system prototype for predicting spring flood volumes in Swedish rivers

NASA Astrophysics Data System (ADS)

Foster, Kean; Bertacchi Uvo, Cintia; Olsson, Jonas

2018-05-01

Hydropower makes up nearly half of Sweden's electrical energy production. However, the distribution of the water resources is not aligned with demand, as most of the inflows to the reservoirs occur during the spring flood period. This means that carefully planned reservoir management is required to help redistribute water resources to ensure optimal production and accurate forecasts of the spring flood volume (SFV) is essential for this. The current operational SFV forecasts use a historical ensemble approach where the HBV model is forced with historical observations of precipitation and temperature. In this work we develop and test a multi-model prototype, building on previous work, and evaluate its ability to forecast the SFV in 84 sub-basins in northern Sweden. The hypothesis explored in this work is that a multi-model seasonal forecast system incorporating different modelling approaches is generally more skilful at forecasting the SFV in snow dominated regions than a forecast system that utilises only one approach. The testing is done using cross-validated hindcasts for the period 1981-2015 and the results are evaluated against both climatology and the current system to determine skill. Both the multi-model methods considered showed skill over the reference forecasts. The version that combined the historical modelling chain, dynamical modelling chain, and statistical modelling chain performed better than the other and was chosen for the prototype. The prototype was able to outperform the current operational system 57 % of the time on average and reduce the error in the SFV by ˜ 6 % across all sub-basins and forecast dates.

Development and validation of a low-frequency modeling code for high-moment transmitter rod antennas

NASA Astrophysics Data System (ADS)

Jordan, Jared Williams; Sternberg, Ben K.; Dvorak, Steven L.

2009-12-01

The goal of this research is to develop and validate a low-frequency modeling code for high-moment transmitter rod antennas to aid in the design of future low-frequency TX antennas with high magnetic moments. To accomplish this goal, a quasi-static modeling algorithm was developed to simulate finite-length, permeable-core, rod antennas. This quasi-static analysis is applicable for low frequencies where eddy currents are negligible, and it can handle solid or hollow cores with winding insulation thickness between the antenna's windings and its core. The theory was programmed in Matlab, and the modeling code has the ability to predict the TX antenna's gain, maximum magnetic moment, saturation current, series inductance, and core series loss resistance, provided the user enters the corresponding complex permeability for the desired core magnetic flux density. In order to utilize the linear modeling code to model the effects of nonlinear core materials, it is necessary to use the correct complex permeability for a specific core magnetic flux density. In order to test the modeling code, we demonstrated that it can accurately predict changes in the electrical parameters associated with variations in the rod length and the core thickness for antennas made out of low carbon steel wire. These tests demonstrate that the modeling code was successful in predicting the changes in the rod antenna characteristics under high-current nonlinear conditions due to changes in the physical dimensions of the rod provided that the flux density in the core was held constant in order to keep the complex permeability from changing.

Making to Measure? Reconsidering Assessment in Professional Continuing Education

ERIC Educational Resources Information Center

Fenwick, Tara

2009-01-01

Drawing on studies of teachers, accountants and pharmacists conducted in Canada, this essay examines models for assessing professional learning that currently enjoy widespread use in continuing education. These models include professional growth plans, self-administered tests and learning logs, and they are often used for regulatory as well as…

How does temporal variability in model parameters affect the risk conclusions from MCnest?

EPA Science Inventory

USEPA recently began using the MCnest model for avian risk for adverse reproductive effects due to pesticide exposure. A more advanced version is currently under development and beta testing for use with threatened and endangered birds. For both versions, a species database has...

Hierarchical Bayesian Models of Subtask Learning

ERIC Educational Resources Information Center

Anglim, Jeromy; Wynton, Sarah K. A.

2015-01-01

The current study used Bayesian hierarchical methods to challenge and extend previous work on subtask learning consistency. A general model of individual-level subtask learning was proposed focusing on power and exponential functions with constraints to test for inconsistency. To study subtask learning, we developed a novel computer-based booking…

Noise level measurements on the UMTA Mark I Diagnostic Car (R42 MODEL)

DOT National Transportation Integrated Search

1971-10-01

The R42 Model mass transit car currently operating on the "N" line of the new York City Transit System was selected for experimentation and tests. For this purpose, the car was instrumented and designated as the UMTA Mark I Diagnostic Car. Noise leve...

Temperament Pathways to Childhood Disruptive Behavior and Adolescent Substance Abuse: Testing a Cascade Model

ERIC Educational Resources Information Center

Martel, Michelle M.; Pierce, Laura; Nigg, Joel T.; Jester, Jennifer M.; Adams, Kenneth; Puttler, Leon I.; Buu, Anne; Fitzgerald, Hiram; Zucker, Robert A.

2009-01-01

Temperament traits may increase risk for developmental psychopathology like Attention-Deficit/Hyperactivity Disorder (ADHD) and disruptive behaviors during childhood, as well as predisposing to substance abuse during adolescence. In the current study, a cascade model of trait pathways to adolescent substance abuse was examined. Component…

The Mystery Tubes: Teaching Pupils about Hypothetical Modelling

ERIC Educational Resources Information Center

Kenrick, Carole

2017-01-01

This article recounts the author's working experience of one method by which pupils' understanding of the epistemologies of science can be developed, specifically how scientists can develop hypothetical models and test them through simulations. She currently uses this approach for transition lessons with pupils in upper primary or lower secondary…

Adult Human Stem Cell-Derived Cardiomyocytes: An Alternative Model for Evaluating Chemical and Environmental Pollutant Cardiotoxicity

EPA Science Inventory

Heart disease is increasing globally with a significant percentage of the increase being attributed to chemical and pollution exposures. Currently, no alternative or in vitro testing models exist to rapidly and accurately determine the cardiac effects of chemicals and/or pollutan...

Modelling of the reactive sputtering process with non-uniform discharge current density and different temperature conditions

NASA Astrophysics Data System (ADS)

Vašina, P; Hytková, T; Eliáš, M

2009-05-01

The majority of current models of the reactive magnetron sputtering assume a uniform shape of the discharge current density and the same temperature near the target and the substrate. However, in the real experimental set-up, the presence of the magnetic field causes high density plasma to form in front of the cathode in the shape of a toroid. Consequently, the discharge current density is laterally non-uniform. In addition to this, the heating of the background gas by sputtered particles, which is usually referred to as the gas rarefaction, plays an important role. This paper presents an extended model of the reactive magnetron sputtering that assumes the non-uniform discharge current density and which accommodates the gas rarefaction effect. It is devoted mainly to the study of the behaviour of the reactive sputtering rather that to the prediction of the coating properties. Outputs of this model are compared with those that assume uniform discharge current density and uniform temperature profile in the deposition chamber. Particular attention is paid to the modelling of the radial variation of the target composition near transitions from the metallic to the compound mode and vice versa. A study of the target utilization in the metallic and compound mode is performed for two different discharge current density profiles corresponding to typical two pole and multipole magnetics available on the market now. Different shapes of the discharge current density were tested. Finally, hysteresis curves are plotted for various temperature conditions in the reactor.

NASA Stennis Space Center Test Technology Branch Activities

NASA Technical Reports Server (NTRS)

Solano, Wanda M.

2000-01-01

This paper provides a short history of NASA Stennis Space Center's Test Technology Laboratory and briefly describes the variety of engine test technology activities and developmental project initiatives. Theoretical rocket exhaust plume modeling, acoustic monitoring and analysis, hand held fire imaging, heat flux radiometry, thermal imaging and exhaust plume spectroscopy are all examples of current and past test activities that are briefly described. In addition, recent efforts and visions focused on accomodating second, third, and fourth generation flight vehicle engine test requirements are discussed.

The circuit parameters measurement of the SABALAN-I plasma focus facility and comparison with Lee Model

NASA Astrophysics Data System (ADS)

Karimi, F. S.; Saviz, S.; Ghoranneviss, M.; Salem, M. K.; Aghamir, F. M.

The circuit parameters are investigated in a Mather-type plasma focus device. The experiments are performed in the SABALAN-I plasma focus facility (2 kJ, 20 kV, 10 μF). A 12-turn Rogowski coil is built and used to measure the time derivative of discharge current (dI/dt). The high pressure test has been performed in this work, as alternative technique to short circuit test to determine the machine circuit parameters and calibration factor of the Rogowski coil. The operating parameters are calculated by two methods and the results show that the relative error of determined parameters by method I, are very low in comparison to method II. Thus the method I produces more accurate results than method II. The high pressure test is operated with this assumption that no plasma motion and the circuit parameters may be estimated using R-L-C theory given that C0 is known. However, for a plasma focus, even at highest permissible pressure it is found that there is significant motion, so that estimated circuit parameters not accurate. So the Lee Model code is used in short circuit mode to generate the computed current trace for fitting to the current waveform was integrated from current derivative signal taken with Rogowski coil. Hence, the dynamics of plasma is accounted for into the estimation and the static bank parameters are determined accurately.

NASA GRC and MSFC Space-Plasma Arc Testing Procedures

NASA Technical Reports Server (NTRS)

Ferguson, Dale C.; Vayner, Boris V.; Galofaro, Joel T.; Hillard, G. Barry; Vaughn, Jason; Schneider, Todd

2007-01-01

Tests of arcing and current collection in simulated space plasma conditions have been performed at the NASA Glenn Research Center (GRC) in Cleveland, Ohio, for over 30 years and at the Marshall Space Flight Center (MSFC) in Huntsville, Alabama, for almost as long. During this period, proper test conditions for accurate and meaningful space simulation have been worked out, comparisons with actual space performance in spaceflight tests and with real operational satellites have been made, and NASA has achieved our own internal standards for test protocols. It is the purpose of this paper to communicate the test conditions, test procedures, and types of analysis used at NASA GRC and MSFC to the space environmental testing community at large, to help with international space-plasma arcing-testing standardization. Discussed herein are neutral gas conditions, plasma densities and uniformity, vacuum chamber sizes, sample sizes and Debye lengths, biasing samples versus self-generated voltages, floating samples versus grounded samples, test electrical conditions, arc detection, preventing sustained discharges during testing, real samples versus idealized samples, validity of LEO tests for GEO samples, extracting arc threshold information from arc rate versus voltage tests, snapover, current collection, and glows at positive sample bias, Kapton pyrolysis, thresholds for trigger arcs, sustained arcs, dielectric breakdown and Paschen discharge, tether arcing and testing in very dense plasmas (i.e. thruster plumes), arc mitigation strategies, charging mitigation strategies, models, and analysis of test results. Finally, the necessity of testing will be emphasized, not to the exclusion of modeling, but as part of a complete strategy for determining when and if arcs will occur, and preventing them from occurring in space.

Software Engineering Tools for Scientific Models

NASA Technical Reports Server (NTRS)

Abrams, Marc; Saboo, Pallabi; Sonsini, Mike

2013-01-01

Software tools were constructed to address issues the NASA Fortran development community faces, and they were tested on real models currently in use at NASA. These proof-of-concept tools address the High-End Computing Program and the Modeling, Analysis, and Prediction Program. Two examples are the NASA Goddard Earth Observing System Model, Version 5 (GEOS-5) atmospheric model in Cell Fortran on the Cell Broadband Engine, and the Goddard Institute for Space Studies (GISS) coupled atmosphere- ocean model called ModelE, written in fixed format Fortran.

Nonlinear Simulation of DIII-D Plasma and Poloidal Systems Using DINA and Simulink

NASA Astrophysics Data System (ADS)

Walker, M. L.; Leuer, J. A.; Deranian, R. D.; Humphreys, D. A.; Khayrutdinov, R. R.

2002-11-01

Hardware-in-the-loop simulation capability was developed previously for poloidal shape control testing using Matlab Simulink [1]. This has been upgraded by replacing a linearized plasma model with the DINA nonlinear plasma evolution code [2]. In addition to its use for shape control studies, this new capability will allow study of current profile control using the DINA model of electron cyclotron current drive (ECCD) and current profile information soon to be available from the Plasma Control System (PCS) real time EFIT [3] calculation. We describe the incorporation of DINA into the Simulink DIII-D tokamak systems model and results of validating this combined model against DIII-D data. \\vspace0.1em [1] J.A. Leuer, et al., 18th IEEE/NPSS SOFE (1999), p. 531. [2] R.R. Khayrutdinov, V.E. Lukash, J. Comput. Phys. 109, 193 (1993). [3] J.R. Ferron, et al., Nucl. Fusion 38, 1055 (1988).

Teaching-Learning Conceptions and Academic Achievement: The Mediating Role of Test Anxiety

ERIC Educational Resources Information Center

Bas, Gökhan

2016-01-01

The current research aimed at examining the mediating role of test anxiety in the relationship between teaching-learning conceptions and academic achievement. The correlation investigation model was adopted in this research. The participants of the research were volunteering teachers (n = 108) and students (n = 526) from five different high…

Lead-Free vs Tin-Lead Reliability of Advanced Electronic Assemblies

NASA Technical Reports Server (NTRS)

Ghaffarian, Reza

2005-01-01

This presentation will provide the technical background and specific information published in literature related to reliability test, analyses, modeling, and associated issues for lead-free solder package assemblies in comparison to their tin-lead solder alloys. It also presents current understanding of lead-free thermal cycle test performance in support.

Family Environments, Adrenarche, and Sexual Maturation: A Longitudinal Test of a Life History Model

ERIC Educational Resources Information Center

Ellis, Bruce J.; Essex, Marilyn J.

2007-01-01

Life history theorists have proposed that humans have evolved to be sensitive to specific features of early childhood environments and that exposure to different environments biases children toward development of different reproductive strategies, including differential pubertal timing. The current research provides a longitudinal test of this…

Integrating Telemedicine for Disaster Response: Testing the Emergency Telemedicine Technology Acceptance Model

ERIC Educational Resources Information Center

Davis, Theresa M.

2013-01-01

Background: There is little evidence that technology acceptance is well understood in healthcare. The hospital environment is complex and dynamic creating a challenge when new technology is introduced because it impacts current processes and workflows which can significantly affect patient care delivery and outcomes. This study tested the effect…

So Many Chemicals, So Little Time... Evolution of ...

EPA Pesticide Factsheets

Current testing is limited by traditional testing models and regulatory systems. An overview is given of high throughput screening approaches to provide broader chemical and biological coverage, toxicokinetics and molecular pathway data and tools to facilitate utilization for regulatory application. Presentation at the NCSU Toxicology lecture series on the Evolution of Computational Toxicology

Identification of an unsteady aerodynamic model up to high angle of attack regime

NASA Astrophysics Data System (ADS)

Fan, Yigang

1997-12-01

The harmonic oscillatory tests for a fighter aircraft configuration using the Dynamic Plunge-Pitch-Roll (DyPPiR) model mount at Virginia Tech Stability Wind Tunnel are described and analyzed. The corresponding data reduction methods are developed on the basis of multirate digital signal processing techniques. Since the model is sting-mounted to the support system of DyPPiR, the Discrete Fourier Transform (DFT) is first used to identify the frequencies of the elastic modes of sting. Then the sampling rate conversion systems are built up in digital domain to resample the data at a lower rate without introducing distortions to the signals of interest. Finally linear-phase Finite Impulse Response (FIR) filters are designed by Remez exchange algorithm to extract the aerodynamic characteristics responses to the programmed motions from the resampled measurements. These data reduction procedures are also illustrated through examples. The results obtained from the harmonic oscillatory tests are then illustrated and the associated flow mechanisms are discussed. Since no significant hysteresis loops are observed for the lift and the drag coefficients for the current angle of attack range and the tested reduced frequencies, the dynamic lags of separated and vortex flow effects are small in the current oscillatory tests. However, large hysteresis loops are observed for pitch moment coefficient in the current tests. This observation suggests that at current flow conditions, pitch moment has large pitch rate dotalpha dependencies. Then the nondimensional maximum pitch rate \\ qsb{max} is introduced to characterize these harmonic oscillatory motions. It is found that at current flow conditions, all the hysteresis loops of pitch moment coefficient with same \\ qsb{max} are tangential to one another at both top and bottom of the loops, implying approximately same maximum offset of these loops from static values. Several cases are also illustrated. Based on the results obtained and those from references, a state-space model is developed to describe the unsteady aerodynamic characteristics up to the high angle of attack regime. A nondimensional coordinate is introduced as the state variable describing the flow separation or vortex burst. First-order differential equation is used to govern the dynamics of flow separation or vortex bursting through this state variable. To be valid for general configurations, Taylor series expansions in terms of the input variables are used in the determination of aerodynamic characteristics, resembling the current approach of the stability derivatives. However, these derivatives are longer constant. They are dependent on the state variable of flow separation or vortex burst. In this way, the changes in stability derivatives with the angle of attack are included dynamically. The performance of the model is then validated by the wind-tunnel measurements of an NACA 0015 airfoil, a 70sp° delta wing and, finally two F-18 aircraft configurations. The results obtained show that within the framework of the proposed model, it is possible to obtain good agreement with different unsteady wind tunnel data in high angle-of-attack regime.

Temperature-Dependent Characterization, Modeling, and Switching Speed-Limitation Analysis of Third-Generation 10-kV SiC MOSFET

DOE PAGES

Ji, Shiqi; Zheng, Sheng; Wang, Fei; ...

2017-07-06

The temperature-dependent characteristics of the third-generation 10-kV/20-A SiC MOSFET including the static characteristics and switching performance are carried out in this paper. The steady-state characteristics, including saturation current, output characteristics, antiparallel diode, and parasitic capacitance, are tested. Here, a double pulse test platform is constructed including a circuit breaker and gate drive with >10-kV insulation and also a hotplate under the device under test for temperature-dependent characterization during switching transients. The switching performance is tested under various load currents and gate resistances at a 7-kV dc-link voltage from 25 to 125 C and compared with previous 10-kV MOSFETs. A simplemore » behavioral model with its parameter extraction method is proposed to predict the temperature-dependent characteristics of the 10-kV SiC MOSFET. The switching speed limitations, including the reverse recovery of SiC MOSFET's body diode, overvoltage caused by stray inductance, crosstalk, heat sink, and electromagnetic interference to the control are discussed based on simulations and experimental results.« less

Design of experiments enhanced statistical process control for wind tunnel check standard testing

NASA Astrophysics Data System (ADS)

Phillips, Ben D.

The current wind tunnel check standard testing program at NASA Langley Research Center is focused on increasing data quality, uncertainty quantification and overall control and improvement of wind tunnel measurement processes. The statistical process control (SPC) methodology employed in the check standard testing program allows for the tracking of variations in measurements over time as well as an overall assessment of facility health. While the SPC approach can and does provide researchers with valuable information, it has certain limitations in the areas of process improvement and uncertainty quantification. It is thought by utilizing design of experiments methodology in conjunction with the current SPC practices that one can efficiently and more robustly characterize uncertainties and develop enhanced process improvement procedures. In this research, methodologies were developed to generate regression models for wind tunnel calibration coefficients, balance force coefficients and wind tunnel flow angularities. The coefficients of these regression models were then tracked in statistical process control charts, giving a higher level of understanding of the processes. The methodology outlined is sufficiently generic such that this research can be applicable to any wind tunnel check standard testing program.

Temperature-Dependent Characterization, Modeling, and Switching Speed-Limitation Analysis of Third-Generation 10-kV SiC MOSFET

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ji, Shiqi; Zheng, Sheng; Wang, Fei

The temperature-dependent characteristics of the third-generation 10-kV/20-A SiC MOSFET including the static characteristics and switching performance are carried out in this paper. The steady-state characteristics, including saturation current, output characteristics, antiparallel diode, and parasitic capacitance, are tested. Here, a double pulse test platform is constructed including a circuit breaker and gate drive with >10-kV insulation and also a hotplate under the device under test for temperature-dependent characterization during switching transients. The switching performance is tested under various load currents and gate resistances at a 7-kV dc-link voltage from 25 to 125 C and compared with previous 10-kV MOSFETs. A simplemore » behavioral model with its parameter extraction method is proposed to predict the temperature-dependent characteristics of the 10-kV SiC MOSFET. The switching speed limitations, including the reverse recovery of SiC MOSFET's body diode, overvoltage caused by stray inductance, crosstalk, heat sink, and electromagnetic interference to the control are discussed based on simulations and experimental results.« less

Application of historical mobility testing to sensor-based robotic performance

NASA Astrophysics Data System (ADS)

Willoughby, William E.; Jones, Randolph A.; Mason, George L.; Shoop, Sally A.; Lever, James H.

2006-05-01

The USA Engineer Research and Development Center (ERDC) has conducted on-/off-road experimental field testing with full-sized and scale-model military vehicles for more than fifty years. Some 4000 acres of local terrain are available for tailored field evaluations or verification/validation of future robotic designs in a variety of climatic regimes. Field testing and data collection procedures, as well as techniques for quantifying terrain in engineering terms, have been developed and refined into algorithms and models for predicting vehicle-terrain interactions and resulting forces or speeds of military-sized vehicles. Based on recent experiments with Matilda, Talon, and Pacbot, these predictive capabilities appear to be relevant to most robotic systems currently in development. Utilization of current testing capabilities with sensor-based vehicle drivers, or use of the procedures for terrain quantification from sensor data, would immediately apply some fifty years of historical knowledge to the development, refinement, and implementation of future robotic systems. Additionally, translation of sensor-collected terrain data into engineering terms would allow assessment of robotic performance a priori deployment of the actual system and ensure maximum system performance in the theater of operation.

CP violation in multibody B decays from QCD factorization

NASA Astrophysics Data System (ADS)

Klein, Rebecca; Mannel, Thomas; Virto, Javier; Vos, K. Keri

2017-10-01

We test a data-driven approach based on QCD factorization for charmless three-body B-decays by confronting it to measurements of CP violation in B - → π - π + π -. While some of the needed non-perturbative objects can be directly extracted from data, some others can, so far, only be modelled. Although this approach is currently model dependent, we comment on the perspectives to reduce this model dependence. While our model naturally accommodates the gross features of the Dalitz distribution, it cannot quantitatively explain the details seen in the current experimental data on local CP asymmetries. We comment on possible refinements of our simple model and conclude by briefly discussing a possible extension of the model to large invariant masses, where large local CP asymmetries have been measured.

Study of emissions from light-duty vehicles in Denver. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1981-08-31

A sample of 300 light-duty vehicles normally operated in the Denver metropolitan area was tested for emissions and fuel economy. The vehicles were from the 1978 through 1982 model years and included both passenger cars and light-duty trucks. One purpose of the program was to gather information for calculations and projections of ambient air quality. Another purpose was to assemble data on current model year vehicles for use in the support of Inspection/Maintenance and other regulatory programs. The vehicles were tested for exhaust emissions utilizing the Federal Test Procedure, the Highway Fuel Economy Test (HFET), and four short mode tests.more » 125 vehicles from the 1980-82 model years received an evaporative emission test using the sealed housing evaporative determination (SHED) technique. Other actions were taken in relation to each vehicle tested. These included an engine and emission control system maladjustment/disablement and status inspection, driveability evaluations, and owner interviews to obtain vehicle maintenance and usage data.« less

Dynamic response of induced pressures, suckdown, and temperatures for two tandem jet STOVL configurations

NASA Technical Reports Server (NTRS)

Wardwell, Douglas A.; Corsiglia, Victor R.; Kuhn, Richard E.

1992-01-01

NASA Ames Research Center has been conducting a program to improve the methods for predicting the jet-induced lift loss (suckdown) and hot gas ingestion on jet Short Takeoff and Vertical Landing (STOVL) aircraft during hover near the ground. As part of that program, small-scale hover tests were conducted to expand the current data base and to improve upon the current empirical methods for predicting jet-induced lift loss and hot gas ingestion (HGI) effects. This report is one of three data reports covering data obtained from hover tests conducted at Lockheed Aeronautical Systems, Rye Canyon Facility. It will include dynamic (time dependent) test data for both lift loss and HGI parameters (height, nozzle temperature, nozzle pressure ratio, and inlet location). The flat plate models tested were tandem jet configurations with three planform variations and variable position side-by-side sucking inlets mounted above the planform. Temperature time lags from 8-15 seconds were observed before the model temperatures stabilize. This was larger than the expected 1.5-second lag calculated from literature. Several possible explanations for the flow temperatures to stabilize may include some, or all, of the following: thermocouple lag, radiation to the model surface, and heat loss to the ground board. Further investigations are required to understand the reasons for this temperature lag.

Orion MPCV Service Module Avionics Ring Pallet Testing, Correlation, and Analysis

NASA Technical Reports Server (NTRS)

Staab, Lucas; Akers, James; Suarez, Vicente; Jones, Trevor

2012-01-01

The NASA Orion Multi-Purpose Crew Vehicle (MPCV) is being designed to replace the Space Shuttle as the main manned spacecraft for the agency. Based on the predicted environments in the Service Module avionics ring, an isolation system was deemed necessary to protect the avionics packages carried by the spacecraft. Impact, sinusoidal, and random vibration testing were conducted on a prototype Orion Service Module avionics pallet in March 2010 at the NASA Glenn Research Center Structural Dynamics Laboratory (SDL). The pallet design utilized wire rope isolators to reduce the vibration levels seen by the avionics packages. The current pallet design utilizes the same wire rope isolators (M6-120-10) that were tested in March 2010. In an effort to save cost and schedule, the Finite Element Models of the prototype pallet tested in March 2010 were correlated. Frequency Response Function (FRF) comparisons, mode shape and frequency were all part of the correlation process. The non-linear behavior and the modeling the wire rope isolators proved to be the most difficult part of the correlation process. The correlated models of the wire rope isolators were taken from the prototype design and integrated into the current design for future frequency response analysis and component environment specification.

Evaluation of LOINC for Representing Constitutional Cytogenetic Test Result Reports

PubMed Central

Heras, Yan Z.; Mitchell, Joyce A.; Williams, Marc S.; Brothman, Arthur R.; Huff, Stanley M.

2009-01-01

Genetic testing is becoming increasingly important to medical practice. Integrating genetics and genomics data into electronic medical records is crucial in translating genetic discoveries into improved patient care. Information technology, especially Clinical Decision Support Systems, holds great potential to help clinical professionals take full advantage of genomic advances in their daily medical practice. However, issues relating to standard terminology and information models for exchanging genetic testing results remain relatively unexplored. This study evaluates whether the current LOINC standard is adequate to represent constitutional cytogenetic test result reports using sample result reports from ARUP Laboratories. The results demonstrate that current standard terminology is insufficient to support the needs of coding cytogenetic test results. The terminology infrastructure must be developed before clinical information systems will be able to handle the high volumes of genetic data expected in the near future. PMID:20351857

Evaluation of LOINC for representing constitutional cytogenetic test result reports.

PubMed

Heras, Yan Z; Mitchell, Joyce A; Williams, Marc S; Brothman, Arthur R; Huff, Stanley M

2009-11-14

Genetic testing is becoming increasingly important to medical practice. Integrating genetics and genomics data into electronic medical records is crucial in translating genetic discoveries into improved patient care. Information technology, especially Clinical Decision Support Systems, holds great potential to help clinical professionals take full advantage of genomic advances in their daily medical practice. However, issues relating to standard terminology and information models for exchanging genetic testing results remain relatively unexplored. This study evaluates whether the current LOINC standard is adequate to represent constitutional cytogenetic test result reports using sample result reports from ARUP Laboratories. The results demonstrate that current standard terminology is insufficient to support the needs of coding cytogenetic test results. The terminology infrastructure must be developed before clinical information systems will be able to handle the high volumes of genetic data expected in the near future.

Regression Models For Multivariate Count Data

PubMed Central

Zhang, Yiwen; Zhou, Hua; Zhou, Jin; Sun, Wei

2016-01-01

Data with multivariate count responses frequently occur in modern applications. The commonly used multinomial-logit model is limiting due to its restrictive mean-variance structure. For instance, analyzing count data from the recent RNA-seq technology by the multinomial-logit model leads to serious errors in hypothesis testing. The ubiquity of over-dispersion and complicated correlation structures among multivariate counts calls for more flexible regression models. In this article, we study some generalized linear models that incorporate various correlation structures among the counts. Current literature lacks a treatment of these models, partly due to the fact that they do not belong to the natural exponential family. We study the estimation, testing, and variable selection for these models in a unifying framework. The regression models are compared on both synthetic and real RNA-seq data. PMID:28348500

Regression Models For Multivariate Count Data.

PubMed

Zhang, Yiwen; Zhou, Hua; Zhou, Jin; Sun, Wei

2017-01-01

Data with multivariate count responses frequently occur in modern applications. The commonly used multinomial-logit model is limiting due to its restrictive mean-variance structure. For instance, analyzing count data from the recent RNA-seq technology by the multinomial-logit model leads to serious errors in hypothesis testing. The ubiquity of over-dispersion and complicated correlation structures among multivariate counts calls for more flexible regression models. In this article, we study some generalized linear models that incorporate various correlation structures among the counts. Current literature lacks a treatment of these models, partly due to the fact that they do not belong to the natural exponential family. We study the estimation, testing, and variable selection for these models in a unifying framework. The regression models are compared on both synthetic and real RNA-seq data.

Aerothermodynamics of Blunt Body Entry Vehicles. Chapter 3

NASA Technical Reports Server (NTRS)

Hollis, Brian R.; Borrelli, Salvatore

2011-01-01

In this chapter, the aerothermodynamic phenomena of blunt body entry vehicles are discussed. Four topics will be considered that present challenges to current computational modeling techniques for blunt body environments: turbulent flow, non-equilibrium flow, rarefied flow, and radiation transport. Examples of comparisons between computational tools to ground and flight-test data will be presented in order to illustrate the challenges existing in the numerical modeling of each of these phenomena and to provide test cases for evaluation of Computational Fluid Dynamics (CFD) code predictions.

Aerothermodynamics of blunt body entry vehicles

NASA Astrophysics Data System (ADS)

Hollis, Brian R.; Borrelli, Salvatore

2012-01-01

In this chapter, the aerothermodynamic phenomena of blunt body entry vehicles are discussed. Four topics will be considered that present challenges to current computational modeling techniques for blunt body environments: turbulent flow, non-equilibrium flow, rarefied flow, and radiation transport. Examples of comparisons between computational tools to ground and flight-test data will be presented in order to illustrate the challenges existing in the numerical modeling of each of these phenomena and to provide test cases for evaluation of computational fluid dynamics (CFD) code predictions.

Future Combat System Spinout 1 Technical Field Test - Establishing and Implementing Models and Simulations System of Systems Verification, Validation and Accreditation Practices, Methodologies and Procedures

DTIC Science & Technology

2009-11-24

assisted by the Brigade Combat Team (BCT) Modernization effort, the use of Models and Simulations ( M &S) becomes more crucial in supporting major...in 2008 via a slice of the Current Force (CF) BCT structure. To ensure realistic operational context, a M &S System-of- Systems (SoS) level...messages, and constructive representation of platforms, vehicles, and terrain. The M &S federation also provided test control, data collection, and live

How well do basic models describe the turbidity currents coming down Monterey and Congo Canyon?

NASA Astrophysics Data System (ADS)

Cartigny, M.; Simmons, S.; Heerema, C.; Xu, J. P.; Azpiroz, M.; Clare, M. A.; Cooper, C.; Gales, J. A.; Maier, K. L.; Parsons, D. R.; Paull, C. K.; Sumner, E. J.; Talling, P.

2017-12-01

Turbidity currents rival rivers in their global capacity to transport sediment and organic carbon. Furthermore, turbidity currents break submarine cables that now transport >95% of our global data traffic. Accurate turbidity current models are thus needed to quantify their transport capacity and to predict the forces exerted on seafloor structures. Despite this need, existing numerical models are typically only calibrated with scaled-down laboratory measurements due to the paucity of direct measurements of field-scale turbidity currents. This lack of calibration thus leaves much uncertainty in the validity of existing models. Here we use the most detailed observations of turbidity currents yet acquired to validate one of the most fundamental models proposed for turbidity currents, the modified Chézy model. Direct measurements on which the validation is based come from two sites that feature distinctly different flow modes and grain sizes. The first are from the multi-institution Coordinated Canyon Experiment (CCE) in Monterey Canyon, California. An array of six moorings along the canyon axis captured at least 15 flow events that lasted up to hours. The second is the deep-sea Congo Canyon, where 10 finer grained flows were measured by a single mooring, each lasting several days. Moorings captured depth-resolved velocity and suspended sediment concentration at high resolution (<30 second) for each of the 25 events. We use both datasets to test the most basic model available for turbidity currents; the modified Chézy model. This basic model has been very useful for river studies over the past 200 years, as it provides a rapid estimate of how flow velocity varies with changes in river level and energy slope. Chézy-type models assume that the gravitational force of the flow equals the friction of the river-bed. Modified Chézy models have been proposed for turbidity currents. However, the absence of detailed measurements of friction and sediment concentration within full-scale turbidity currents has forced modellers to make rough assumptions for these parameters. Here we use mooring data to deduce observation-based relations that can replace the previous assumptions. This improvement will significantly enhance the model predictions and allow us to better constrain the behaviour of turbidity currents.

Alternatives to In Vivo Draize Rabbit Eye and Skin Irritation Tests with a Focus on 3D Reconstructed Human Cornea-Like Epithelium and Epidermis Models

PubMed Central

Lee, Miri; Hwang, Jee-Hyun; Lim, Kyung-Min

2017-01-01

Human eyes and skin are frequently exposed to chemicals accidentally or on purpose due to their external location. Therefore, chemicals are required to undergo the evaluation of the ocular and dermal irritancy for their safe handling and use before release into the market. Draize rabbit eye and skin irritation test developed in 1944, has been a gold standard test which was enlisted as OECD TG 404 and OECD TG 405 but it has been criticized with respect to animal welfare due to invasive and cruel procedure. To replace it, diverse alternatives have been developed: (i) For Draize eye irritation test, organotypic assay, in vitro cytotoxicity-based method, in chemico tests, in silico prediction model, and 3D reconstructed human cornea-like epithelium (RhCE); (ii) For Draize skin irritation test, in vitro cytotoxicity-based cell model, and 3D reconstructed human epidermis models (RhE). Of these, RhCE and RhE models are getting spotlight as a promising alternative with a wide applicability domain covering cosmetics and personal care products. In this review, we overviewed the current alternatives to Draize test with a focus on 3D human epithelium models to provide an insight into advancing and widening their utility. PMID:28744350

A Bayesian Model for the Estimation of Latent Interaction and Quadratic Effects When Latent Variables Are Non-Normally Distributed

ERIC Educational Resources Information Center

Kelava, Augustin; Nagengast, Benjamin

2012-01-01

Structural equation models with interaction and quadratic effects have become a standard tool for testing nonlinear hypotheses in the social sciences. Most of the current approaches assume normally distributed latent predictor variables. In this article, we present a Bayesian model for the estimation of latent nonlinear effects when the latent…

A comparison of traditional anti-inflammation and anti-infection medicinal plants with current evidence from biomedical research: Results from a regional study

PubMed Central

Vieira, A.

2010-01-01

Background: In relation to pharmacognosy, an objective of many ethnobotanical studies is to identify plant species to be further investigated, for example, tested in disease models related to the ethnomedicinal application. To further warrant such testing, research evidence for medicinal applications of these plants (or of their major phytochemical constituents and metabolic derivatives) is typically analyzed in biomedical databases. Methods: As a model of this process, the current report presents novel information regarding traditional anti-inflammation and anti-infection medicinal plant use. This information was obtained from an interview-based ethnobotanical study; and was compared with current biomedical evidence using the Medline® database. Results: Of the 8 anti-infection plant species identified in the ethnobotanical study, 7 have related activities reported in the database; and of the 6 anti-inflammation plants, 4 have related activities in the database. Conclusion: Based on novel and complimentary results from the ethnobotanical and biomedical database analyses, it is suggested that some of these plants warrant additional investigation of potential anti-inflammatory or anti-infection activities in related disease models, and also additional studies in other population groups. PMID:21589754

Experimental and numerical analysis of interfilament resistances in NbTi strands

NASA Astrophysics Data System (ADS)

Breschi, M.; Massimini, M.; Ribani, P. L.; Spina, T.; Corato, V.

2014-05-01

Superconducting strands are composite wires made of fine superconducting filaments embedded in a metallic matrix. The transverse resistivity among superconducting filaments affects the coupling losses during electromagnetic transients and the electro-thermal behavior of the wire in case of a quench. A direct measurement of the transverse interfilament resistance as a function of temperature in NbTi multi-filamentary wires was performed at the ENEA Frascati Superconductivity Division, Italy by means of a four-probe method. The complexity of these measurements is remarkable, due to the current distribution phenomena that occur among superconducting filaments during these tests. A two-dimensional finite element method model of the wire cross section and a three-dimensional electrical circuit model of the wire sample developed at the University of Bologna are applied here to derive qualitative and quantitative information about the transverse electrical resistance matrix. The experiment is aimed at verifying the qualitative behaviors and trends predicted by the numerical calculations, especially concerning the current redistribution length and consequent length effects of the sample under test. A fine tuning of the model parameters at the filament level allowed us to reproduce the experimental results and get quantitative information about the current distribution phenomena between filaments.

Low Speed and High Speed Correlation of SMART Active Flap Rotor Loads

NASA Technical Reports Server (NTRS)

Kottapalli, Sesi B. R.

2010-01-01

Measured, open loop and closed loop data from the SMART rotor test in the NASA Ames 40- by 80- Foot Wind Tunnel are compared with CAMRAD II calculations. One open loop high-speed case and four closed loop cases are considered. The closed loop cases include three high-speed cases and one low-speed case. Two of these high-speed cases include a 2 deg flap deflection at 5P case and a test maximum-airspeed case. This study follows a recent, open loop correlation effort that used a simple correction factor for the airfoil pitching moment Mach number. Compared to the earlier effort, the current open loop study considers more fundamental corrections based on advancing blade aerodynamic conditions. The airfoil tables themselves have been studied. Selected modifications to the HH-06 section flap airfoil pitching moment table are implemented. For the closed loop condition, the effect of the flap actuator is modeled by increased flap hinge stiffness. Overall, the open loop correlation is reasonable, thus confirming the basic correctness of the current semi-empirical modifications; the closed loop correlation is also reasonable considering that the current flap model is a first generation model. Detailed correlation results are given in the paper.

Multi-component testing using HZ-PAN and AgZ-PAN Sorbents for OSPREY Model validation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garn, Troy G.; Greenhalgh, Mitchell; Lyon, Kevin L.

2015-04-01

In efforts to further develop the capability of the Off-gas SeParation and RecoverY (OSPREY) model, multi-component tests were completed using both HZ-PAN and AgZ-PAN sorbents. The primary purpose of this effort was to obtain multi-component xenon and krypton capacities for comparison to future OSPREY predicted multi-component capacities using previously acquired Langmuir equilibrium parameters determined from single component isotherms. Experimental capacities were determined for each sorbent using two feed gas compositions of 1000 ppmv xenon and 150 ppmv krypton in either a helium or air balance. Test temperatures were consistently held at 220 K and the gas flowrate was 50 sccm.more » Capacities were calculated from breakthrough curves using TableCurve® 2D software by Jandel Scientific. The HZ-PAN sorbent was tested in the custom designed cryostat while the AgZ-PAN was tested in a newly installed cooling apparatus. Previous modeling validation efforts indicated the OSPREY model can be used to effectively predict single component xenon and krypton capacities for both engineered form sorbents. Results indicated good agreement with the experimental and predicted capacity values for both krypton and xenon on the sorbents. Overall, the model predicted slightly elevated capacities for both gases which can be partially attributed to the estimation of the parameters and the uncertainty associated with the experimental measurements. Currently, OSPREY is configured such that one species adsorbs and one does not (i.e. krypton in helium). Modification of OSPREY code is currently being performed to incorporate multiple adsorbing species and non-ideal interactions of gas phase species with the sorbent and adsorbed phases. Once these modifications are complete, the sorbent capacities determined in the present work will be used to validate OSPREY multicomponent adsorption predictions.« less

Bypass Diode Temperature Tests of a Solar Array Coupon Under Space Thermal Environment Conditions

NASA Technical Reports Server (NTRS)

Wright, Kenneth H., Jr.; Schneider, Todd A.; Vaughn, Jason A.; Hoang, Bao; Wong, Frankie; Wu, Gordon

2016-01-01

Tests were performed on a 56-cell Advanced Triple Junction solar array coupon whose purpose was to determine margin available for bypass diodes integrated with new, large multi-junction solar cells that are manufactured from a 4-inch wafer. The tests were performed under high vacuum with coupon back side thermal conditions of both cold and ambient. The bypass diodes were subjected to a sequence of increasing discrete current steps from 0 Amp to 2.0 Amp in steps of 0.25 Amp. At each current step, a temperature measurement was obtained via remote viewing by an infrared camera. This paper discusses the experimental methodology, experiment results, and the thermal model.

Real time flaw detection and characterization in tube through partial least squares and SVR: Application to eddy current testing

NASA Astrophysics Data System (ADS)

Ahmed, Shamim; Miorelli, Roberto; Calmon, Pierre; Anselmi, Nicola; Salucci, Marco

2018-04-01

This paper describes Learning-By-Examples (LBE) technique for performing quasi real time flaw localization and characterization within a conductive tube based on Eddy Current Testing (ECT) signals. Within the framework of LBE, the combination of full-factorial (i.e., GRID) sampling and Partial Least Squares (PLS) feature extraction (i.e., GRID-PLS) techniques are applied for generating a suitable training set in offine phase. Support Vector Regression (SVR) is utilized for model development and inversion during offine and online phases, respectively. The performance and robustness of the proposed GIRD-PLS/SVR strategy on noisy test set is evaluated and compared with standard GRID/SVR approach.

Effect of Microscopic Damage Events on Static and Ballistic Impact Strength of Triaxial Braid Composites

NASA Technical Reports Server (NTRS)

Littell, Justin D.; Binienda, Wieslaw K.; Arnold, William A.; Roberts, Gary D.; Goldberg, Robert K.

2010-01-01

The reliability of impact simulations for aircraft components made with triaxial-braided carbon-fiber composites is currently limited by inadequate material property data and lack of validated material models for analysis. Methods to characterize the material properties used in the analytical models from a systematically obtained set of test data are also lacking. A macroscopic finite element based analytical model to analyze the impact response of these materials has been developed. The stiffness and strength properties utilized in the material model are obtained from a set of quasi-static in-plane tension, compression and shear coupon level tests. Full-field optical strain measurement techniques are applied in the testing, and the results are used to help in characterizing the model. The unit cell of the braided composite is modeled as a series of shell elements, where each element is modeled as a laminated composite. The braided architecture can thus be approximated within the analytical model. The transient dynamic finite element code LS-DYNA is utilized to conduct the finite element simulations, and an internal LS-DYNA constitutive model is utilized in the analysis. Methods to obtain the stiffness and strength properties required by the constitutive model from the available test data are developed. Simulations of quasi-static coupon tests and impact tests of a represented braided composite are conducted. Overall, the developed method shows promise, but improvements that are needed in test and analysis methods for better predictive capability are examined.

Childhood conditions and current physical performance among non-institutionalized individuals aged 50+ in Israel.

PubMed

Weinstein, Galit

2016-12-01

Adverse socioeconomic conditions in childhood have been previously linked with high risk of various health conditions. However, the association with future physical function has been less studied. Hand grip strength and chair-rising time are objective measures of physical capability indicating current and future health outcomes. The aim of this study was to test the hypothesis that perceived socio-economic status in childhood is related to current measures of physical function, among Israeli participants of the Survey of Health, Ageing and Retirement in Europe project. The study included 2300 participants aged 50 years or older (mean age 68 ± 10; 56 % women). Generalized linear regression models were used to examine the associations of childhood wealth and number of books in residence with grip strength and time to complete five rises from a chair. Logistic regression models were used to assess the relationships between the early life conditions and the ability to perform the physical tests. Adjustment was made for current income or household wealth, and for demographic, anthropometric, health, and life-style measures. Being wealthy and having a large number of books at home in childhood was associated with a stronger hand grip and a better chair-rise test performance. These associations were more robust in women compared to men, and persisted after adjustment for potential covariates. In addition, childhood wealth and number of books were associated with lower risk of being unable to perform the tests. Thus, early-life programming may contribute to physical function indicators in mid- and late-life.

Numerical modeling and experimental validation of thermoplastic composites induction welding

NASA Astrophysics Data System (ADS)

Palmieri, Barbara; Nele, Luigi; Galise, Francesco

2018-05-01

In this work, a numerical simulation and experimental test of the induction welding of continuous fibre-reinforced thermoplastic composites (CFRTPCs) was provided. The thermoplastic Polyamide 66 (PA66) with carbon fiber fabric was used. Using a dedicated software (JMag Designer), the influence of the fundamental process parameters such as temperature, current and holding time was investigated. In order to validate the results of the simulations, and therefore the numerical model used, experimental tests were carried out, and the temperature values measured during the tests were compared with the aid of an optical pyrometer, with those provided by the numerical simulation. The mechanical properties of the welded joints were evaluated by single lap shear tests.

Childhood maltreatment and college students' current suicidal ideation: a test of the hopelessness theory.

PubMed

Gibb, B E; Alloy, L B; Abramson, L Y; Rose, D T; Whitehouse, W G; Hogan, M E

2001-01-01

Few studies have examined the relation between childhood maltreatment and adult suicidality within the context of a coherent theoretical model. The current study evaluates the ability of the hopelessness theory of depression's (Abramson, Metalsky, & Alloy, 1989) etiological chain to account for this relation in a sample of 297 undergraduates. Supporting the model, emotional, but not physical or sexual, maltreatment was uniquely related to average levels of suicidal ideation across a 2.5-year follow-up. Further, students' cognitive styles and average levels of hopelessness partially mediated this relation. Although these results cannot speak to causality, they support the developmental model evaluated.

Damping Effects of Drogue Parachutes on Orion Crew Module Dynamics

NASA Technical Reports Server (NTRS)

Aubuchon, Vanessa V.

2013-01-01

Currently, simulation predictions of the Orion Crew Module (CM) dynamics with drogue parachutes deployed are under-predicting the amount of damping as seen in free-flight tests. The Apollo Legacy Chute Damping model has been resurrected and applied to the Orion system. The legacy model has been applied to predict CM damping under drogue parachutes for both Vertical Spin Tunnel free flights and the Pad Abort-1 flight test. Comparisons between the legacy Apollo prediction method and test data are favorable. A key hypothesis in the Apollo legacy drogue damping analysis is that the drogue parachutes' net load vector aligns with the CM drogue attachment point velocity vector. This assumption seems reasonable and produces good results, but has never been quantitatively proven. The wake of the CM influences the drogue parachutes, which makes performance predictions of the parachutes difficult. Many of these effects are not currently modeled in the simulations. A forced oscillation test of the CM with parachutes was conducted in the NASA LaRC 20-Ft Vertical Spin Tunnel (VST) to gather additional data to validate and refine the Apollo legacy drogue model. A second loads balance was added to the original Orion VST model to measure the drogue parachute loads independently of the CM. The objective of the test was to identify the contribution of the drogues to CM damping and provide additional information to quantify wake effects and the interactions between the CM and parachutes. The drogue parachute force vector was shown to be highly dependent on the CM wake characteristics. Based on these wind tunnel test data, the Apollo Legacy Chute Damping model was determined to be a sufficient approximation of the parachute dynamics in relationship to the CM dynamics for preliminary entry vehicle system design. More wake effects should be included to better model the system. These results are being used to improve simulation model fidelity of CM flight with drogues deployed, which has been identified by the project as key to a successful Orion Critical Design Review.

A model of electron collecting plasma contractors

NASA Technical Reports Server (NTRS)

Davis, V. A.; Katz, I.; Mandell, M. J.; Parks, D. E.

1989-01-01

A model of plasma contractors is being developed, which can be used to describe electron collection in a laboratory test tank and in the space environment. To validate the model development, laboratory experiments are conducted in which the source plasma is separated from the background plasma by a double layer. Model calculations show that an increase in ionization rate with potential produces a steep rise in collected current with increasing potential.

A Nested Nearshore Nutrient Model (N&Sup3;M) for ...

EPA Pesticide Factsheets

Nearshore conditions drive phenomena like harmful algal blooms (HABs), and the nearshore and coastal margin are the parts of the Great Lakes most used by humans. To assess conditions, optimize monitoring, and evaluate management options, a model of nearshore nutrient transport and algal dynamics is being developed. The model targets a “regional” spatial scale, similar to the Great Lakes Aquatic Habitat Framework's sub-basins, which divide the nearshore into 30 regions. Model runs are 365 days, a whole season temporal scale, reporting at 3 hour intervals. N³M uses output from existing hydrodynamic models and simple transport kinetics. The nutrient transport component of this model is largely complete, and is being tested with various hydrodynamic data sets. The first test case covers a 200 km² area between two major tributaries to Lake Michigan, the Grand and Muskegon. N³M currently simulates phosphorous and chloride, selected for their distinct in-lake transport dynamics; nitrogen will be added. Initial results for 2003, 2010, and 2015 show encouraging correlations with field measurements. Initially implemented in MatLab, the model is currently implemented in Python and leverages multi-processor computation. The 4D in-browser visualizer Cesium is used to view model output, time varying satellite imagery, and field observations. not applicable

An improved PSO-SVM model for online recognition defects in eddy current testing

NASA Astrophysics Data System (ADS)

Liu, Baoling; Hou, Dibo; Huang, Pingjie; Liu, Banteng; Tang, Huayi; Zhang, Wubo; Chen, Peihua; Zhang, Guangxin

2013-12-01

Accurate and rapid recognition of defects is essential for structural integrity and health monitoring of in-service device using eddy current (EC) non-destructive testing. This paper introduces a novel model-free method that includes three main modules: a signal pre-processing module, a classifier module and an optimisation module. In the signal pre-processing module, a kind of two-stage differential structure is proposed to suppress the lift-off fluctuation that could contaminate the EC signal. In the classifier module, multi-class support vector machine (SVM) based on one-against-one strategy is utilised for its good accuracy. In the optimisation module, the optimal parameters of classifier are obtained by an improved particle swarm optimisation (IPSO) algorithm. The proposed IPSO technique can improve convergence performance of the primary PSO through the following strategies: nonlinear processing of inertia weight, introductions of the black hole and simulated annealing model with extremum disturbance. The good generalisation ability of the IPSO-SVM model has been validated through adding additional specimen into the testing set. Experiments show that the proposed algorithm can achieve higher recognition accuracy and efficiency than other well-known classifiers and the superiorities are more obvious with less training set, which contributes to online application.

Motivation, treatment engagement and psychosocial outcomes in outpatients with severe mental illness: a test of Self-Determination Theory.

PubMed

Jochems, Eline C; Duivenvoorden, Hugo J; van Dam, Arno; van der Feltz-Cornelis, Christina M; Mulder, Cornelis L

2017-09-01

Currently, it is unclear whether Self-Determination Theory (SDT) applies to the mental health care of patients with severe mental illness (SMI). Therefore, the current study tested the process model of SDT in a sample of outpatients with SMI. Participants were 294 adult outpatients with a primary diagnosis of a psychotic disorder or a personality disorder and their clinicians (n = 57). Structural equation modelling was used to test the hypothesized relationships between autonomy support, perceived competence, types of motivation, treatment engagement, psychosocial functioning and quality of life at two time points and across the two diagnostic groups. The expected relations among the SDT variables were found, but additional direct paths between perceived competence and clinical outcomes were needed to obtain good model fit. The obtained process model was found to be stable across time and different diagnostic patient groups, and was able to explain 18% to 36% of variance in treatment engagement, psychosocial functioning and quality of life. It is concluded that SDT can be a useful basis for interventions in the mental health care for outpatients with SMI. Additional experimental research is needed to confirm the causality of the relations between the SDT constructs and their ability to influence treatment outcomes. Copyright © 2016 John Wiley & Sons, Ltd.

Effect of test exercises and mask donning on measured respirator fit.

PubMed

Crutchfield, C D; Fairbank, E O; Greenstein, S L

1999-12-01

Quantitative respirator fit test protocols are typically defined by a series of fit test exercises. A rationale for the protocols that have been developed is generally not available. There also is little information available that describes the effect or effectiveness of the fit test exercises currently specified in respiratory protection standards. This study was designed to assess the relative impact of fit test exercises and mask donning on respirator fit as measured by a controlled negative pressure and an ambient aerosol fit test system. Multiple donnings of two different sizes of identical respirator models by each of 14 test subjects showed that donning affects respirator fit to a greater degree than fit test exercises. Currently specified fit test protocols emphasize test exercises, and the determination of fit is based on a single mask donning. A rationale for a modified fit test protocol based on fewer, more targeted test exercises and multiple mask donnings is presented. The modified protocol identified inadequately fitting respirators as effectively as the currently specified Occupational Safety and Health Administration (OSHA) quantitative fit test protocol. The controlled negative pressure system measured significantly (p < 0.0001) more respirator leakage than the ambient aerosol fit test system. The bend over fit test exercise was found to be predictive of poor respirator fit by both fit test systems. For the better fitting respirators, only the talking exercise generated aerosol fit factors that were significantly lower (p < 0.0001) than corresponding donning fit factors.

Bayesian modelling of lung function data from multiple-breath washout tests.

PubMed

Mahar, Robert K; Carlin, John B; Ranganathan, Sarath; Ponsonby, Anne-Louise; Vuillermin, Peter; Vukcevic, Damjan

2018-05-30

Paediatric respiratory researchers have widely adopted the multiple-breath washout (MBW) test because it allows assessment of lung function in unsedated infants and is well suited to longitudinal studies of lung development and disease. However, a substantial proportion of MBW tests in infants fail current acceptability criteria. We hypothesised that a model-based approach to analysing the data, in place of traditional simple empirical summaries, would enable more efficient use of these tests. We therefore developed a novel statistical model for infant MBW data and applied it to 1197 tests from 432 individuals from a large birth cohort study. We focus on Bayesian estimation of the lung clearance index, the most commonly used summary of lung function from MBW tests. Our results show that the model provides an excellent fit to the data and shed further light on statistical properties of the standard empirical approach. Furthermore, the modelling approach enables the lung clearance index to be estimated by using tests with different degrees of completeness, something not possible with the standard approach. Our model therefore allows previously unused data to be used rather than discarded, as well as routine use of shorter tests without significant loss of precision. Beyond our specific application, our work illustrates a number of important aspects of Bayesian modelling in practice, such as the importance of hierarchical specifications to account for repeated measurements and the value of model checking via posterior predictive distributions. Copyright © 2018 John Wiley & Sons, Ltd.

Limitations of bootstrap current models

DOE PAGES

Belli, Emily A.; Candy, Jefferey M.; Meneghini, Orso; ...

2014-03-27

We assess the accuracy and limitations of two analytic models of the tokamak bootstrap current: (1) the well-known Sauter model and (2) a recent modification of the Sauter model by Koh et al. For this study, we use simulations from the first-principles kinetic code NEO as the baseline to which the models are compared. Tests are performed using both theoretical parameter scans as well as core- to-edge scans of real DIII-D and NSTX plasma profiles. The effects of extreme aspect ratio, large impurity fraction, energetic particles, and high collisionality are studied. In particular, the error in neglecting cross-species collisional couplingmore » – an approximation inherent to both analytic models – is quantified. Moreover, the implications of the corrections from kinetic NEO simulations on MHD equilibrium reconstructions is studied via integrated modeling with kinetic EFIT.« less

Exploring the validity of the Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT) with established emotions measures.

PubMed

Roberts, Richard D; Schulze, Ralf; O'Brien, Kristin; MacCann, Carolyn; Reid, John; Maul, Andy

2006-11-01

Emotions measures represent an important means of obtaining construct validity evidence for emotional intelligence (EI) tests because they have the same theoretical underpinnings. Additionally, the extent to which both emotions and EI measures relate to intelligence is poorly understood. The current study was designed to address these issues. Participants (N = 138) completed the Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT), two emotions measures, as well as four intelligence tests. Results provide mixed support for the model hypothesized to underlie the MSCEIT, with emotions research and EI measures failing to load on the same factor. The emotions measures loaded on the same factor as intelligence measures. The validity of certain EI components (in particular, Emotion Perception), as currently assessed, appears equivocal. Copyright 2006 APA, all rights reserved.

MEMS Deformable Mirror Technology Development for Space-Based Exoplanet Detection

NASA Astrophysics Data System (ADS)

Bierden, Paul; Cornelissen, S.; Ryan, P.

2014-01-01

In the search for earth-like extrasolar planets that has become an important objective for NASA, a critical technology development requirement is to advance deformable mirror (DM) technology. High-actuator-count DMs are critical components for nearly all proposed coronagraph instrument concepts. The science case for exoplanet imaging is strong, and rapid recent advances in test beds with DMs made using microelectromechanical system (MEMS) technology have motivated a number of compelling mission concepts that set technical specifications for their use as wavefront controllers. This research will advance the technology readiness of the MEMS DMs components that are currently at the forefront of the field, and the project will be led by the manufacturer of those components, Boston Micromachines Corporation (BMC). The project aims to demonstrate basic functionality and performance of this key component in critical test environments and in simulated operational environments, while establishing model-based predictions of its performance relative to launch and space environments. Presented will be the current status of the project with modeling and initial test results.

Bounding species distribution models

USGS Publications Warehouse

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

2011-01-01

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

Bounding Species Distribution Models

NASA Technical Reports Server (NTRS)

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

2011-01-01

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

Analysis on trust influencing factors and trust model from multiple perspectives of online Auction

NASA Astrophysics Data System (ADS)

Yu, Wang

2017-10-01

Current reputation models lack the research on online auction trading completely so they cannot entirely reflect the reputation status of users and may cause problems on operability. To evaluate the user trust in online auction correctly, a trust computing model based on multiple influencing factors is established. It aims at overcoming the efficiency of current trust computing methods and the limitations of traditional theoretical trust models. The improved model comprehensively considers the trust degree evaluation factors of three types of participants according to different participation modes of online auctioneers, to improve the accuracy, effectiveness and robustness of the trust degree. The experiments test the efficiency and the performance of our model under different scale of malicious user, under environment like eBay and Sporas model. The experimental results analysis show the model proposed in this paper makes up the deficiency of existing model and it also has better feasibility.

Heat Pipes and Heat Rejection Component Testing at NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Sanzi, James L.; Jaworske, Donald A.

2012-01-01

Titanium-water heat pipes are being evaluated for use in the heat rejection system for space fission power systems. The heat rejection syst em currently comprises heat pipes with a graphite saddle and a composite fin. The heat input is a pumped water loop from the cooling of the power conversion system. The National Aeronautics and Space Administration has been life testing titanium-water heat pipes as well as eval uating several heat pipe radiator designs. The testing includes thermal modeling and verification of model, material compatibility, frozen startup of heat pipe radiators, and simulating low-gravity environments. Future thermal testing of titanium-water heat pipes includes low-g ravity testing of thermosyphons, radiation testing of heat pipes and fin materials, water pump performance testing, as well as Small Busine ss Innovation Research funded deliverable prototype radiator panels.

The test facility for the short prototypes of the LHC superconducting magnets

NASA Astrophysics Data System (ADS)

Delsolaro, W. Venturini; Arn, A.; Bottura, L.; Giloux, C.; Mompo, R.; Siemko, A.; Walckiers, L.

2002-05-01

The LHC development program relies on cryogenic tests of prototype and model magnets. This vigorous program is pursued in a dedicated test facility based on several vertical cryostats working at superfluid helium temperatures. The performance of the facility is detailed. Goals and test equipment for currently performed studies are reviewed: quench analysis and magnet protection studies, measurement of the field quality, test of ancillary electrical equipment like diodes and busbars. The paper covers the equipment available for tests of prototypes and some special series of LHC magnets to come.

Icing simulation: A survey of computer models and experimental facilities

NASA Technical Reports Server (NTRS)

Potapczuk, M. G.; Reinmann, J. J.

1991-01-01

A survey of the current methods for simulation of the response of an aircraft or aircraft subsystem to an icing encounter is presented. The topics discussed include a computer code modeling of aircraft icing and performance degradation, an evaluation of experimental facility simulation capabilities, and ice protection system evaluation tests in simulated icing conditions. Current research focussed on upgrading simulation fidelity of both experimental and computational methods is discussed. The need for increased understanding of the physical processes governing ice accretion, ice shedding, and iced airfoil aerodynamics is examined.

Icing simulation: A survey of computer models and experimental facilities

NASA Technical Reports Server (NTRS)

Potapczuk, M. G.; Reinmann, J. J.

1991-01-01

A survey of the current methods for simulation of the response of an aircraft or aircraft subsystem to an icing encounter is presented. The topics discussed include a computer code modeling of aircraft icing and performance degradation, an evaluation of experimental facility simulation capabilities, and ice protection system evaluation tests in simulated icing conditions. Current research focused on upgrading simulation fidelity of both experimental and computational methods is discussed. The need for the increased understanding of the physical processes governing ice accretion, ice shedding, and iced aerodynamics is examined.

An electrical model of vapor-anode, multitube AMTEC cells[Alkali Metal Thermal to Electric Conversion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tournier, J.M.; El-Genk, M.S.

1998-07-01

A two-dimensional electrical model of vapor-anode, multi-tube AMTEC cells was developed, which included four options of current collector configurations. Simulation results of several cells tested at AFRL showed that electrical losses in the current collector networks and the connecting leads were negligible. The polarization/concentration losses in the TiN electrodes were significant, amounting to 25%--50% of the cell theoretical power, while the contact and BASE ionic losses amounted to less than 16% of the cell theoretical power.

Field Performance of Photovoltaic Systems in the Tucson Desert

NASA Astrophysics Data System (ADS)

Orsburn, Sean; Brooks, Adria; Cormode, Daniel; Greenberg, James; Hardesty, Garrett; Lonij, Vincent; Salhab, Anas; St. Germaine, Tyler; Torres, Gabe; Cronin, Alexander

2011-10-01

At the Tucson Electric Power (TEP) solar test yard, over 20 different grid-connected photovoltaic (PV) systems are being tested. The goal at the TEP solar test yard is to measure and model real-world performance of PV systems and to benchmark new technologies such as holographic concentrators. By studying voltage and current produced by the PV systems as a function of incident irradiance, and module temperature, we can compare our measurements of field-performance (in a harsh desert environment) to manufacturer specifications (determined under laboratory conditions). In order to measure high-voltage and high-current signals, we designed and built reliable, accurate sensors that can handle extreme desert temperatures. We will present several benchmarks of sensors in a controlled environment, including shunt resistors and Hall-effect current sensors, to determine temperature drift and accuracy. Finally we will present preliminary field measurements of PV performance for several different PV technologies.

Towards the development of improved tests for negative symptoms of schizophrenia in a validated animal model.

PubMed

Sahin, Ceren; Doostdar, Nazanin; Neill, Joanna C

2016-10-01

Negative symptoms in schizophrenia remain an unmet clinical need. There is no licensed treatment specifically for this debilitating aspect of the disorder and effect sizes of new therapies are too small to make an impact on quality of life and function. Negative symptoms are multifactorial but often considered in terms of two domains, expressive deficit incorporating blunted affect and poverty of speech and avolition incorporating asociality and lack of drive. There is a clear need for improved understanding of the neurobiology of negative symptoms which can be enabled through the use of carefully validated animal models. While there are several tests for assessing sociability in animals, tests for blunted affect in schizophrenia are currently lacking. Two paradigms have recently been developed for assessing negative affect of relevance to depression in rats. Here we assess their utility for studying negative symptoms in schizophrenia using our well validated model for schizophrenia of sub-chronic (sc) treatment with Phencyclidine (PCP) in adult female rats. Results demonstrate that sc PCP treatment produces a significant negative affect bias in response to a high value reward in the optimistic and affective bias tests. Our results are not easily explained by the known cognitive deficits induced by sc PCP and support the hypothesis of a negative affective bias in this model. We suggest that further refinement of these two tests will provide a means to investigate the neurobiological basis of negative affect in schizophrenia, thus supporting the assessment of efficacy of new targets for this currently untreated symptom domain. Copyright © 2016 Elsevier B.V. All rights reserved.

Multiple testing of food contact materials: a predictive algorithm for assessing the global migration from silicone moulds.

PubMed

Elskens, Marc; Vloeberghs, Daniel; Van Elsen, Liesbeth; Baeyens, Willy; Goeyens, Leo

2012-09-15

For reasons of food safety, packaging and food contact materials must be submitted to migration tests. Testing of silicone moulds is often very laborious, since three replicate tests are required to decide about their compliancy. This paper presents a general modelling framework to predict the sample's compliance or non-compliance using results of the first two migration tests. It compares the outcomes of models with multiple continuous predictors with a class of models involving latent and dummy variables. The model's prediction ability was tested using cross and external validations, i.e. model revalidation each time a new measurement set became available. At the overall migration limit of 10 mg dm(-2), the relative uncertainty on a prediction was estimated to be ~10%. Taking the default values for α and β equal to 0.05, the maximum value that can be predicted for sample compliance was therefore 7 mg dm(-2). Beyond this limit the risk for false compliant results increases significantly, and a third migration test should be performed. The result of this latter test defines the sample's compliance or non-compliance. Propositions for compliancy control inspired by the current dioxin control strategy are discussed. Copyright © 2012 Elsevier B.V. All rights reserved.

Developing Model Benchtop Systems for Microbial Experimental Evolution

NASA Astrophysics Data System (ADS)

Gentry, D.; Wang, J.; Arismendi, D.; Alvarez, J.; Ouandji, C.; Blaich, J.

2017-12-01

Understanding how microbes impact an ecosystem has improved through advances of molecular and genetic tools, but creating complex systems that emulate natural biology goes beyond current technology. In fact, many chemical, biological, and metabolic pathways of even model organisms are still poorly characterized. Even then, standard laboratory techniques for testing microbial impact on environmental change can have many drawbacks; they are time-consuming, labor intensive, and are at risk of contamination. By having an automated process, many of these problems can be reduced or even eliminated. We are developing a benchtop system that can run for long periods of time without the need for human intervention, involve multiple environmental stressors at once, perform real-time adjustments of stressor exposure based on current state of the population, and minimize contamination risks. Our prototype device allows operators to generate an analogue of real world micro-scale ecosystems that can be used to model the effects of disruptive environmental change on microbial ecosystems. It comprises of electronics, mechatronics, and fluidics based systems to control, measure, and evaluate the before and after state of microbial cultures from exposure to environmental stressors. Currently, it uses four parallel growth chambers to perform tests on liquid cultures. To measure the population state, optical sensors (LED/photodiode) are used. Its primary selection pressure is UV-C radiation, a well-studied stressor known for its cell- and DNA- damaging effects and as a mutagen. Future work will involve improving the current growth chambers, as well as implementing additional sensors and environmental stressors into the system. Full integration of multiple culture testing will allow inter-culture comparisons. Besides the temperature and OD sensors, other types of sensors can be integrated such as conductivity, biomass, pH, and dissolved gasses such as CO2 and O2. Additional environmental stressor systems like temperature (extreme heat or cold), metal toxicity, and other forms of radiation will increase the scale and testing range.

Developing Model Benchtop Systems for Microbial Experimental Evolution

NASA Technical Reports Server (NTRS)

Wang, Jonathan; Arismendi, Dillon; Alvarez, Jennifer; Ouandji, Cynthia; Blaich, Justin; Gentry, Diana

2017-01-01

Understanding how microbes impact an ecosystem has improved through advances of molecular and genetic tools, but creating complex systems that emulate natural biology goes beyond current technology. In fact, many chemical, biological, and metabolic pathways of even model organisms are still poorly characterized. Even then, standard laboratory techniques for testing microbial impact on environmental change can have many drawbacks; they are time-consuming, labor intensive, and are at risk of contamination. By having an automated process, many of these problems can be reduced or even eliminated. We are developing a benchtop system that can run for long periods of time without the need for human intervention, involve multiple environmental stressors at once, perform real-time adjustments of stressor exposure based on current state of the population, and minimize contamination risks. Our prototype device allows operators to generate an analogue of real world micro-scale ecosystems that can be used to model the effects of disruptive environmental change on microbial ecosystems. It comprises of electronics, mechatronics, and fluidics based systems to control, measure, and evaluate the before and after state of microbial cultures from exposure to environmental stressors. Currently, it uses four parallel growth chambers to perform tests on liquid cultures. To measure the population state, optical sensors (LED/photodiode) are used. Its primary selection pressure is UV-C radiation, a well-studied stressor known for its cell- and DNA-damaging effects and as a mutagen. Future work will involve improving the current growth chambers, as well as implementing additional sensors and environmental stressors into the system. Full integration of multiple culture testing will allow inter-culture comparisons. Besides the temperature and OD sensors, other types of sensors can be integrated such as conductivity, biomass, pH, and dissolved gasses such as CO and O. Additional environmental stressor systems like temperature (extreme heat or cold), metal toxicity, and other forms of radiation will increase the scale and testing range.

Improved test methods for determining lightning-induced voltages in aircraft

NASA Technical Reports Server (NTRS)

Crouch, K. E.; Plumer, J. A.

1980-01-01

A lumped parameter transmission line with a surge impedance matching that of the aircraft and its return lines was evaluated as a replacement for earlier current generators. Various test circuit parameters were evaluated using a 1/10 scale relative geometric model. Induced voltage response was evaluated by taking measurements on the NASA-Dryden Digital Fly by Wire F-8 aircraft. Return conductor arrangements as well as other circuit changes were also evaluated, with all induced voltage measurements being made on the same circuit for comparison purposes. The lumped parameter transmission line generates a concave front current wave with the peak di/dt near the peak of the current wave which is more representative of lightning. However, the induced voltage measurements when scaled by appropriate scale factors (peak current or di/dt) resulting from both techniques yield comparable results.

Fourier functional analysis for unsteady aerodynamic modeling

NASA Technical Reports Server (NTRS)

Lan, C. Edward; Chin, Suei

1991-01-01

A method based on Fourier analysis is developed to analyze the force and moment data obtained in large amplitude forced oscillation tests at high angles of attack. The aerodynamic models for normal force, lift, drag, and pitching moment coefficients are built up from a set of aerodynamic responses to harmonic motions at different frequencies. Based on the aerodynamic models of harmonic data, the indicial responses are formed. The final expressions for the models involve time integrals of the indicial type advocated by Tobak and Schiff. Results from linear two- and three-dimensional unsteady aerodynamic theories as well as test data for a 70-degree delta wing are used to verify the models. It is shown that the present modeling method is accurate in producing the aerodynamic responses to harmonic motions and the ramp type motions. The model also produces correct trend for a 70-degree delta wing in harmonic motion with different mean angles-of-attack. However, the current model cannot be used to extrapolate data to higher angles-of-attack than that of the harmonic motions which form the aerodynamic model. For linear ramp motions, a special method is used to calculate the corresponding frequency and phase angle at a given time. The calculated results from modeling show a higher lift peak for linear ramp motion than for harmonic ramp motion. The current model also shows reasonably good results for the lift responses at different angles of attack.

A Note on Testing Mediated Effects in Structural Equation Models: Reconciling Past and Current Research on the Performance of the Test of Joint Significance

ERIC Educational Resources Information Center

Valente, Matthew J.; Gonzalez, Oscar; Miocevic, Milica; MacKinnon, David P.

2016-01-01

Methods to assess the significance of mediated effects in education and the social sciences are well studied and fall into two categories: single sample methods and computer-intensive methods. A popular single sample method to detect the significance of the mediated effect is the test of joint significance, and a popular computer-intensive method…

A comparison of fatigue life prediction methodologies for rotorcraft

NASA Technical Reports Server (NTRS)

Everett, R. A., Jr.

1990-01-01

Because of the current U.S. Army requirement that all new rotorcraft be designed to a 'six nines' reliability on fatigue life, this study was undertaken to assess the accuracy of the current safe life philosophy using the nominal stress Palmgrem-Miner linear cumulative damage rule to predict the fatigue life of rotorcraft dynamic components. It has been shown that this methodology can predict fatigue lives that differ from test lives by more than two orders of magnitude. A further objective of this work was to compare the accuracy of this methodology to another safe life method called the local strain approach as well as to a method which predicts fatigue life based solely on crack growth data. Spectrum fatigue tests were run on notched (k(sub t) = 3.2) specimens made of 4340 steel using the Felix/28 tests fairly well, being slightly on the unconservative side of the test data. The crack growth method, which is based on 'small crack' crack growth data and a crack-closure model, also predicted the fatigue lives very well with the predicted lives being slightly longer that the mean test lives but within the experimental scatter band. The crack growth model was also able to predict the change in test lives produced by the rainflow reconstructed spectra.

Testing Viable f(T) Models with Current Observations

NASA Astrophysics Data System (ADS)

Xu, Bing; Yu, Hongwei; Wu, Puxun

2018-03-01

We perform observational tests on the f(T) gravity with the BAO data (including the BOSS DR 12 galaxy sample, the DR12 Lyα-Forests measurement, the new eBOSS DR14 quasar sample, the 6dFGS, and the SDSS), the CMB distance priors from the Planck 2015, the SNIa data from the joint light-curve analysis, the latest H(z) data, and the local value of the Hubble constant. Six different f(T) models are investigated. Furthermore, the ΛCDM is also considered. All models are compared by using the Akaike information criteria (AIC) and the Bayesian information criteria (BIC). Our results show that the ΛCDM remains to be the most favored model by current observations. However, there are also the Hubble constant tension between the Planck measurements and the local Universe observations and the tension between the CMB data and the H(z) data in the ΛCDM. For f(T) models considered in this paper, half, which can reduce to the ΛCDM, have values of {{χ }2}\\min smaller than that of the ΛCDM and can relieve the tensions existing in the ΛCDM. However, they are punished slightly by the BIC due to one extra parameter. Two of six f(T) models, in which the crossing of the phantom divide line can be realized for the equation of state of the effective dark energy and this crossing is shown in this paper to be favored by current observations, are punished by the information criteria. In addition, we find that the logarithmic f(T) model is excluded by cosmological observations.

Improving Climate Projections Using "Intelligent" Ensembles

NASA Technical Reports Server (NTRS)

Baker, Noel C.; Taylor, Patrick C.

2015-01-01

Recent changes in the climate system have led to growing concern, especially in communities which are highly vulnerable to resource shortages and weather extremes. There is an urgent need for better climate information to develop solutions and strategies for adapting to a changing climate. Climate models provide excellent tools for studying the current state of climate and making future projections. However, these models are subject to biases created by structural uncertainties. Performance metrics-or the systematic determination of model biases-succinctly quantify aspects of climate model behavior. Efforts to standardize climate model experiments and collect simulation data-such as the Coupled Model Intercomparison Project (CMIP)-provide the means to directly compare and assess model performance. Performance metrics have been used to show that some models reproduce present-day climate better than others. Simulation data from multiple models are often used to add value to projections by creating a consensus projection from the model ensemble, in which each model is given an equal weight. It has been shown that the ensemble mean generally outperforms any single model. It is possible to use unequal weights to produce ensemble means, in which models are weighted based on performance (called "intelligent" ensembles). Can performance metrics be used to improve climate projections? Previous work introduced a framework for comparing the utility of model performance metrics, showing that the best metrics are related to the variance of top-of-atmosphere outgoing longwave radiation. These metrics improve present-day climate simulations of Earth's energy budget using the "intelligent" ensemble method. The current project identifies several approaches for testing whether performance metrics can be applied to future simulations to create "intelligent" ensemble-mean climate projections. It is shown that certain performance metrics test key climate processes in the models, and that these metrics can be used to evaluate model quality in both current and future climate states. This information will be used to produce new consensus projections and provide communities with improved climate projections for urgent decision-making.

Intelligent Launch and Range Operations Virtual Test Bed (ILRO-VTB)

NASA Technical Reports Server (NTRS)

Bardina, Jorge; Rajkumar, T.

2003-01-01

Intelligent Launch and Range Operations Virtual Test Bed (ILRO-VTB) is a real-time web-based command and control, communication, and intelligent simulation environment of ground-vehicle, launch and range operation activities. ILRO-VTB consists of a variety of simulation models combined with commercial and indigenous software developments (NASA Ames). It creates a hybrid software/hardware environment suitable for testing various integrated control system components of launch and range. The dynamic interactions of the integrated simulated control systems are not well understood. Insight into such systems can only be achieved through simulation/emulation. For that reason, NASA has established a VTB where we can learn the actual control and dynamics of designs for future space programs, including testing and performance evaluation. The current implementation of the VTB simulates the operations of a sub-orbital vehicle of mission, control, ground-vehicle engineering, launch and range operations. The present development of the test bed simulates the operations of Space Shuttle Vehicle (SSV) at NASA Kennedy Space Center. The test bed supports a wide variety of shuttle missions with ancillary modeling capabilities like weather forecasting, lightning tracker, toxic gas dispersion model, debris dispersion model, telemetry, trajectory modeling, ground operations, payload models and etc. To achieve the simulations, all models are linked using Common Object Request Broker Architecture (CORBA). The test bed provides opportunities for government, universities, researchers and industries to do a real time of shuttle launch in cyber space.

MATTS- A Step Towards Model Based Testing

NASA Astrophysics Data System (ADS)

Herpel, H.-J.; Willich, G.; Li, J.; Xie, J.; Johansen, B.; Kvinnesland, K.; Krueger, S.; Barrios, P.

2016-08-01

In this paper we describe a Model Based approach to testing of on-board software and compare it with traditional validation strategy currently applied to satellite software. The major problems that software engineering will face over at least the next two decades are increasing application complexity driven by the need for autonomy and serious application robustness. In other words, how do we actually get to declare success when trying to build applications one or two orders of magnitude more complex than today's applications. To solve the problems addressed above the software engineering process has to be improved at least for two aspects: 1) Software design and 2) Software testing. The software design process has to evolve towards model-based approaches with extensive use of code generators. Today, testing is an essential, but time and resource consuming activity in the software development process. Generating a short, but effective test suite usually requires a lot of manual work and expert knowledge. In a model-based process, among other subtasks, test construction and test execution can also be partially automated. The basic idea behind the presented study was to start from a formal model (e.g. State Machines), generate abstract test cases which are then converted to concrete executable test cases (input and expected output pairs). The generated concrete test cases were applied to an on-board software. Results were collected and evaluated wrt. applicability, cost-efficiency, effectiveness at fault finding, and scalability.

A holistic aging model for Li(NiMnCo)O2 based 18650 lithium-ion batteries

NASA Astrophysics Data System (ADS)

Schmalstieg, Johannes; Käbitz, Stefan; Ecker, Madeleine; Sauer, Dirk Uwe

2014-07-01

Knowledge on lithium-ion battery aging and lifetime estimation is a fundamental aspect for successful market introduction in high-priced goods like electric mobility. This paper illustrates the parameterization of a holistic aging model from accelerated aging tests. More than 60 cells of the same type are tested to analyze different impact factors. In calendar aging tests three temperatures and various SOC are applied to the batteries. For cycle aging tests especially different cycle depths and mean SOC are taken into account. Capacity loss and resistance increase are monitored as functions of time and charge throughput during the tests. From these data physical based functions are obtained, giving a mathematical description of aging. To calculate the stress factors like temperature or voltage, an impedance based electric-thermal model is coupled to the aging model. The model accepts power and current profiles as input, furthermore an ambient air temperature profile can be applied. Various drive cycles and battery management strategies can be tested and optimized using the lifetime prognosis of this tool. With the validation based on different realistic driving profiles and temperatures, a robust foundation is provided.

Development and Validation of Linear Alternator Models for the Advanced Stirling Convertor

NASA Technical Reports Server (NTRS)

Metscher, Jonathan F.; Lewandowski, Edward

2014-01-01

Two models of the linear alternator of the Advanced Stirling Convertor (ASC) have been developed using the Sage 1-D modeling software package. The first model relates the piston motion to electric current by means of a motor constant. The second uses electromagnetic model components to model the magnetic circuit of the alternator. The models are tuned and validated using test data and compared against each other. Results show both models can be tuned to achieve results within 7% of ASC test data under normal operating conditions. Using Sage enables the creation of a complete ASC model to be developed and simulations completed quickly compared to more complex multi-dimensional models. These models allow for better insight into overall Stirling convertor performance, aid with Stirling power system modeling, and in the future support NASA mission planning for Stirling-based power systems.

Development and Validation of Linear Alternator Models for the Advanced Stirling Convertor

NASA Technical Reports Server (NTRS)

Metscher, Jonathan F.; Lewandowski, Edward J.

2015-01-01

Two models of the linear alternator of the Advanced Stirling Convertor (ASC) have been developed using the Sage 1-D modeling software package. The first model relates the piston motion to electric current by means of a motor constant. The second uses electromagnetic model components to model the magnetic circuit of the alternator. The models are tuned and validated using test data and also compared against each other. Results show both models can be tuned to achieve results within 7 of ASC test data under normal operating conditions. Using Sage enables the creation of a complete ASC model to be developed and simulations completed quickly compared to more complex multi-dimensional models. These models allow for better insight into overall Stirling convertor performance, aid with Stirling power system modeling, and in the future support NASA mission planning for Stirling-based power systems.

The determination of the orbit of the Japanese satellite Ajisai and the GEM-T1 and GEM-T2 gravity field models

NASA Technical Reports Server (NTRS)

Sanchez, Braulio V.

1990-01-01

The Japanese Experimental Geodetic Satellite Ajisai was launched on August 12, 1986. In response to the TOPEX-POSEIDON mission requirements, the GSFC Space Geodesy Branch and its associates are producing improved models of the Earth's gravitational field. With the launch of Ajisai, precise laser data is now available which can be used to test many current gravity models. The testing of the various gravity field models show improvements of more than 70 percent in the orbital fits when using GEM-T1 and GEM-T2 relative to results obtained with the earlier GEM-10B model. The GEM-T2 orbital fits are at the 13-cm level (RMS). The results of the tests with the various versions of the GEM-T1 model indicate that the addition of satellite altimetry and surface gravity anomalies as additional data types should improve future gravity field models.

The Langley Research Center CSI phase-0 evolutionary model testbed-design and experimental results

NASA Technical Reports Server (NTRS)

Belvin, W. K.; Horta, Lucas G.; Elliott, K. B.

1991-01-01

A testbed for the development of Controls Structures Interaction (CSI) technology is described. The design philosophy, capabilities, and early experimental results are presented to introduce some of the ongoing CSI research at NASA-Langley. The testbed, referred to as the Phase 0 version of the CSI Evolutionary model (CEM), is the first stage of model complexity designed to show the benefits of CSI technology and to identify weaknesses in current capabilities. Early closed loop test results have shown non-model based controllers can provide an order of magnitude increase in damping in the first few flexible vibration modes. Model based controllers for higher performance will need to be robust to model uncertainty as verified by System ID tests. Data are presented that show finite element model predictions of frequency differ from those obtained from tests. Plans are also presented for evolution of the CEM to study integrated controller and structure design as well as multiple payload dynamics.

Advanced optical position sensors for magnetically suspended wind tunnel models

NASA Technical Reports Server (NTRS)

Lafleur, S.

1985-01-01

A major concern to aerodynamicists has been the corruption of wind tunnel test data by model support structures, such as stings or struts. A technique for magnetically suspending wind tunnel models was considered by Tournier and Laurenceau (1957) in order to overcome this problem. This technique is now implemented with the aid of a Large Magnetic Suspension and Balance System (LMSBS) and advanced position sensors for measuring model attitude and position within the test section. Two different optical position sensors are discussed, taking into account a device based on the use of linear CCD arrays, and a device utilizing area CID cameras. Current techniques in image processing have been employed to develop target tracking algorithms capable of subpixel resolution for the sensors. The algorithms are discussed in detail, and some preliminary test results are reported.

A Model for Teacher Effects from Longitudinal Data without Assuming Vertical Scaling

ERIC Educational Resources Information Center

Mariano, Louis T.; McCaffrey, Daniel F.; Lockwood, J. R.

2010-01-01

There is an increasing interest in using longitudinal measures of student achievement to estimate individual teacher effects. Current multivariate models assume each teacher has a single effect on student outcomes that persists undiminished to all future test administrations (complete persistence [CP]) or can diminish with time but remains…