Sample records for initial experimental test

  1. Experimental Test of the Differential Fluctuation Theorem and a Generalized Jarzynski Equality for Arbitrary Initial States

    NASA Astrophysics Data System (ADS)

    Hoang, Thai M.; Pan, Rui; Ahn, Jonghoon; Bang, Jaehoon; Quan, H. T.; Li, Tongcang

    2018-02-01

    Nonequilibrium processes of small systems such as molecular machines are ubiquitous in biology, chemistry, and physics but are often challenging to comprehend. In the past two decades, several exact thermodynamic relations of nonequilibrium processes, collectively known as fluctuation theorems, have been discovered and provided critical insights. These fluctuation theorems are generalizations of the second law and can be unified by a differential fluctuation theorem. Here we perform the first experimental test of the differential fluctuation theorem using an optically levitated nanosphere in both underdamped and overdamped regimes and in both spatial and velocity spaces. We also test several theorems that can be obtained from it directly, including a generalized Jarzynski equality that is valid for arbitrary initial states, and the Hummer-Szabo relation. Our study experimentally verifies these fundamental theorems and initiates the experimental study of stochastic energetics with the instantaneous velocity measurement.

  2. 75 FR 17174 - Market Test

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-05

    ... POSTAL REGULATORY COMMISSION [Docket No. MT2010-1; Order No. 434] Market Test AGENCY: Postal... notice announcing its intent to initiate a market test. This notice addresses procedural steps associated... intent to initiate a market test beginning on or about May 1, 2010, of an experimental competitive...

  3. Race, Exposure, and Initial Affective Ratings in Interpersonal Attraction.

    ERIC Educational Resources Information Center

    Nikels, Kenneth W.; Hamm, Norman H.

    To test the mere exposure hypothesis, subjects were exposed to 20 slides of black and white stimulus persons. Based upon pre-experimental ratings, each slide had been initially assigned to one of four groups: high favorable black, high favorable white, low favorable black, and low favorable white. The experimental group, consisting of 25 white…

  4. Transport relaxation processes in supercritical fluids

    NASA Astrophysics Data System (ADS)

    Jonas, J.

    The technique for solubility measurements of solids in compressed supercritical fluids using NMR and theoretical analysis of experimental data on collision induced scattering were examined. Initial tests for a determination of solid solubilities in supercritical fluids without mixing were previously described and these preparations have continued. Super critical carbon dioxide dissolving naphthalene, for which solubility data is already available (M. McHugh, M.E. Paulaitis, J. Chem. Eng. Data, Vol. 25 (4), 1980) is being studied. This initial testing of the NMR technique for measuring solubilities in a well characterized system should prove very valuable for our later determinations with the proposed mixing probe. Systematic experimental studies of collision induced spectra in several supercritical fluids using both Raman and Rayleigh scattering are continued. The experimental work on SF6 and CH4 was finished and the experimental data testing of the various theoretical models for collision induced scattering is being analyzed.

  5. Flexural testing on carbon fibre laminates taking into account their different behaviour under tension and compression

    NASA Astrophysics Data System (ADS)

    Serna Moreno, M. C.; Romero Gutierrez, A.; Martínez Vicente, J. L.

    2016-07-01

    An analytical model has been derived for describing the results of three-point-bending tests in materials with different behaviour under tension and compression. The shift of the neutral plane and the damage initiation mode and its location have been defined. The validity of the equations has been reviewed by testing carbon fibre-reinforced polymers (CFRP), typically employed in different weight-critical applications. Both unidirectional and cross-ply laminates have been studied. The initial failure mode produced depends directly on the beam span- thickness relation. Therefore, specimens with different thicknesses have been analysed for examining the damage initiation due to either the bending moment or the out-of-plane shear load. The experimental description of the damage initiation and evolution has been shown by means of optical microscopy. The good agreement between the analytical estimations and the experimental results shows the validity of the analytical model exposed.

  6. Experimental setup for investigation of two-phase (water-air) flows in a tube

    NASA Astrophysics Data System (ADS)

    Kazunin, D. V.; Lashkov, V. A.; Mashek, I. Ch.; Khoronzhuk, R. S.

    2018-05-01

    A special setup was designed and built at St. Petersburg State University for providing experimental research in flow dynamics of the of air-water mixtures in a pipeline. The test section of the setup allows simulating a wide range of flow regimes of a gas-liquid mixture. The parameters of the experimental setup are given; the initial test results are discussed.

  7. Computer Modeling and Simulation of Bullet Impact to the Human Thorax

    DTIC Science & Technology

    2000-06-01

    manufacturers into the design and assessment stag~e of their body armor systems. V50 36 testing as used by body armor manufacturers experimentally identifies a...was due to the use of numerical integration by the experimenters at AFIP to obtain the velocities and displacements. In order to set a standard for... numerical integration. As such, in the sternum velocity graph, the initial downward motion of the experimental results, dependent upon the initial negative

  8. Test results and facility description for a 40-kilowatt stirling engine

    NASA Technical Reports Server (NTRS)

    Kelm, G. G.; Cairelli, J. E.; Walter, R. J.

    1981-01-01

    A 40 kilowatt Stirling engine, its test support facilities, and the experimental procedures used for these tests are described. Operating experience with the engine is discussed, and some initial test results are presented

  9. Test and Analysis Correlation for a Y-Joint Specimen for a Composite Cryotank

    NASA Technical Reports Server (NTRS)

    Mason, Brian H.; Sleight, David W.; Grenoble, Ray

    2015-01-01

    The Composite Cryotank Technology Demonstration (CCTD) project under NASA's Game Changing Development Program (GCDP) developed space technologies using advanced composite materials. Under CCTD, NASA funded the Boeing Company to design and test a number of element-level joint specimens as a precursor to a 2.4-m diameter composite cryotank. Preliminary analyses indicated that the y-joint in the cryotank had low margins of safety; hence the y-joint was considered to be a critical design region. The y-joint design includes a softening strip wedge to reduce localized shear stresses at the skirt/dome interface. In this paper, NASA-developed analytical models will be correlated with the experimental results of a series of positive-peel y-joint specimens from Boeing tests. Initial analytical models over-predicted the experimental strain gage readings in the far-field region by approximately 10%. The over-prediction was attributed to uncertainty in the elastic properties of the laminate and a mismatch between the thermal expansion of the strain gages and the laminate. The elastic properties of the analytical model were adjusted to account for the strain gage differences. The experimental strain gages also indicated a large non-linear effect in the softening strip region that was not predicted by the analytical model. This non-linear effect was attributed to delamination initiating in the softening strip region at below 20% of the failure load for the specimen. Because the specimen was contained in a thermally insulated box during cryogenic testing to failure, delamination initiation and progression was not visualized during the test. Several possible failure initiation locations were investigated, and a most likely failure scenario was determined that correlated well with the experimental data. The most likely failure scenario corresponded to damage initiating in the softening strip and delamination extending to the grips at final failure.

  10. Testing and modeling of PBX-9591 shock initiation

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

    Lam, Kim; Foley, Timothy; Novak, Alan

    2010-01-01

    This paper describes an ongoing effort to develop a detonation sensitivity test for PBX-9501 that is suitable for studying pristine and damaged HE. The approach involves testing and comparing the sensitivities of HE pressed to various densities and those of pre-damaged samples with similar porosities. The ultimate objectives are to understand the response of pre-damaged HE to shock impacts and to develop practical computational models for use in system analysis codes for HE safety studies. Computer simulation with the CTH shock physics code is used to aid the experimental design and analyze the test results. In the calculations, initiation andmore » growth or failure of detonation are modeled with the empirical HVRB model. The historical LANL SSGT and LSGT were reviewed and it was determined that a new, modified gap test be developed to satisfy the current requirements. In the new test, the donor/spacer/acceptor assembly is placed in a holder that is designed to work with fixtures for pre-damaging the acceptor sample. CTH simulations were made of the gap test with PBX-9501 samples pressed to three different densities. The calculated sensitivities were validated by test observations. The agreement between the computed and experimental critical gap thicknesses, ranging from 9 to 21 mm under various test conditions, is well within 1 mm. These results show that the numerical modeling is a valuable complement to the experimental efforts in studying and understanding shock initiation of PBX-9501.« less

  11. Adaptive design of visual perception experiments

    NASA Astrophysics Data System (ADS)

    O'Connor, John D.; Hixson, Jonathan; Thomas, James M., Jr.; Peterson, Matthew S.; Parasuraman, Raja

    2010-04-01

    Meticulous experimental design may not always prevent confounds from affecting experimental data acquired during visual perception experiments. Although experimental controls reduce the potential effects of foreseen sources of interference, interaction, or noise, they are not always adequate for preventing the confounding effects of unforeseen forces. Visual perception experimentation is vulnerable to unforeseen confounds because of the nature of the associated cognitive processes involved in the decision task. Some confounds are beyond the control of experimentation, such as what a participant does immediately prior to experimental participation, or the participant's attitude or emotional state. Other confounds may occur through ignorance of practical control methods on the part of the experiment's designer. The authors conducted experiments related to experimental fatigue and initially achieved significant results that were, upon re-examination, attributable to a lack of adequate controls. Re-examination of the original results and the processes and events that led to them yielded a second experimental design with more experimental controls and significantly different results. The authors propose that designers of visual perception experiments can benefit from planning to use a test-fix-test or adaptive experimental design cycle, so that unforeseen confounds in the initial design can be remedied.

  12. A comparison of experimental and theoretical results for rotordynamic coefficients of four annular gas seals

    NASA Technical Reports Server (NTRS)

    Childs, D. W.; Nelson, C. C.; Elrod, D.; Nicks, C.

    1985-01-01

    The test facility and initial test program developed to experimentally measure the fluid forces induced by annular gas seals is described. A comparison of theoretically predicted and experimentally obtained data for smooth and honeycomb seals is provided. And a comparison of experimental data from the tests of three smooth-rotor/smooth-stator seals is provided. The leakage of the working fluid through the seal, the pressure gradient along the seal length, entrance pressure-loss data, and rotordynamic coefficients provide a basis for comparison. A short discussion on seal theory is included, and various rotordynamic coefficient identification schemes are described.

  13. Construction of an Exploratory List of Chemicals to Initiate the Search for Halon Alternatives

    DTIC Science & Technology

    1991-06-01

    of owne-depletion effectiveness is based on atmospheric modeling. The only experimental work is the determination of possible reaction paths and...results, and additional relevant comments. These compounds should be tested in a selective series of experiments based on the insights used in the...will generate initial information with regard to the relative ordering of the compounds in terms of screen properties. Careful experimentation will

  14. Preclinical Assessment of a Strategy to Minimize the Abuse Liability of Opiate Medications for Pain

    DTIC Science & Technology

    2015-07-01

    Animal subjects typically undergo handling by the experimenter prior to a pre- test phase, where their initial preference for one of the environments is...other words, the initial pre- test is presumed to be predictive 6 of the eventual post -treatment test , where animals are given a choice of...environments and if they spend more time in the drug-paired environment on the test day, they are thought to be drug seeking or craving. However, in the

  15. Alternate methodologies to experimentally investigate shock initiation properties of explosives

    NASA Astrophysics Data System (ADS)

    Svingala, Forrest R.; Lee, Richard J.; Sutherland, Gerrit T.; Benjamin, Richard; Boyle, Vincent; Sickels, William; Thompson, Ronnie; Samuels, Phillip J.; Wrobel, Erik; Cornell, Rodger

    2017-01-01

    Reactive flow models are desired for new explosive formulations early in the development stage. Traditionally, these models are parameterized by carefully-controlled 1-D shock experiments, including gas-gun testing with embedded gauges and wedge testing with explosive plane wave lenses (PWL). These experiments are easy to interpret due to their 1-D nature, but are expensive to perform and cannot be performed at all explosive test facilities. This work investigates alternative methods to probe shock-initiation behavior of new explosives using widely-available pentolite gap test donors and simple time-of-arrival type diagnostics. These experiments can be performed at a low cost at most explosives testing facilities. This allows experimental data to parameterize reactive flow models to be collected much earlier in the development of an explosive formulation. However, the fundamentally 2-D nature of these tests may increase the modeling burden in parameterizing these models and reduce general applicability. Several variations of the so-called modified gap test were investigated and evaluated for suitability as an alternative to established 1-D gas gun and PWL techniques. At least partial agreement with 1-D test methods was observed for the explosives tested, and future work is planned to scope the applicability and limitations of these experimental techniques.

  16. Early detection and progression of decay in L-joints and lap-joints in a moderate decay hazard zone

    Treesearch

    Carol A. Clausen; Terry L. Highley; Daniel L. Lindner

    2006-01-01

    Accelerated test methods are needed to evaluate the initiation and progression of decay in wood exposed aboveground. The relationship between test conditions and initiation of decay, however, is poorly understood. Southern pine and maple L-joints and lap-joints were exposed aboveground in a configuration that encouraged water entrapment at the Valley View Experimental...

  17. Prevention of the Post traumatic Fibrotic Response in Joints

    DTIC Science & Technology

    2016-12-01

    researchers focusing on research associated with post -traumatic joint stiffness. This team has grown from a group of three initial Principal Investigators...The formation of the Translational Research Partnership ensured reaching the stated objective. Two Specific Aims were defined to test the...body weight of rabbits during the initial 8 weeks of the experimental study. During this time the rabbits were treated with tested and control

  18. Adaptive Multi-Layer LMS Controller Design and Application to Active Vibration Suppression on a Truss and Proposed Impact Analysis Technique

    DTIC Science & Technology

    2001-06-01

    Setup and Initiation ........................................................ 83 2. Simulation 1 (19 Hz, Y-axis of Node 18, Piezo #2...175 INITIAL DISTRIBUTION LIST ................................................................................... 187 ix...system for the sake of testing and simplicity. The Adaptive Multi-Layered LMS Controller was developed one piece at a time. After initial experimental

  19. Numerical simulation of Composition B high explosive charge desensitization in gap test assembly after loading by precursor wave

    NASA Astrophysics Data System (ADS)

    Balagansky, I. A.; Stepanov, A. A.

    2016-03-01

    Results of numerical research into the desensitization of high explosive charges in water gap test-based experimental assemblies are presented. The experimental data are discussed, and the analysis using ANSYS AUTODYN 14.5 is provided. The desensitization phenomenon is well reproduced in numerical simulation using the JWL EOS and the Lee-Tarver kinetic equation for modeling of the initiation of heterogeneous high explosives with as well as without shock front waves. The analysis of the wave processes occurring during the initiation of the acceptor HE charge has been carried out. Peculiarities of the wave processes in the water gap test assemblies, which can influence the results of sensitivity measurement, have been studied. In particular, it has been established that precursor waves in the walls of the gap test assemblies can influence the detonation transmission distance.

  20. Experimental and Computational Study of Ductile Fracture in Small Punch Tests

    PubMed Central

    Bargmann, Swantje; Hähner, Peter

    2017-01-01

    A unified experimental-computational study on ductile fracture initiation and propagation during small punch testing is presented. Tests are carried out at room temperature with unnotched disks of different thicknesses where large-scale yielding prevails. In thinner specimens, the fracture occurs with severe necking under membrane tension, whereas for thicker ones a through thickness shearing mode prevails changing the crack orientation relative to the loading direction. Computational studies involve finite element simulations using a shear modified Gurson-Tvergaard-Needleman porous plasticity model with an integral-type nonlocal formulation. The predicted punch load-displacement curves and deformed profiles are in good agreement with the experimental results. PMID:29039748

  1. Experimental and Computational Study of Ductile Fracture in Small Punch Tests.

    PubMed

    Gülçimen Çakan, Betül; Soyarslan, Celal; Bargmann, Swantje; Hähner, Peter

    2017-10-17

    A unified experimental-computational study on ductile fracture initiation and propagation during small punch testing is presented. Tests are carried out at room temperature with unnotched disks of different thicknesses where large-scale yielding prevails. In thinner specimens, the fracture occurs with severe necking under membrane tension, whereas for thicker ones a through thickness shearing mode prevails changing the crack orientation relative to the loading direction. Computational studies involve finite element simulations using a shear modified Gurson-Tvergaard-Needleman porous plasticity model with an integral-type nonlocal formulation. The predicted punch load-displacement curves and deformed profiles are in good agreement with the experimental results.

  2. Comparison of a 3-D DEM simulation with MRI data

    NASA Astrophysics Data System (ADS)

    Ng, Tang-Tat; Wang, Changming

    2001-04-01

    This paper presents a comparison of a granular material studied experimentally and numerically. Simple shear tests were performed inside the magnetic core of magnetic resonance imaging (MRI) equipment. Spherical pharmaceutical pills were used as the granular material, with each pill's centre location determined by MRI. These centre locations in the initial assembly were then used as the initial configuration in the numerical simulation using the discrete element method. The contact properties between pharmaceutical pills used in the numerical simulation were obtained experimentally. The numerical predication was compared with experimental data at both macroscopic and microscopic levels. Good agreement was found at both levels.

  3. Description of Liquid Nitrogen Experimental Test Facility

    NASA Technical Reports Server (NTRS)

    Jurns, John M.; Jacobs, Richard E.; Saiyed, Naseem H.

    1991-01-01

    The Liquid Nitrogen Test Facility is a unique test facility for ground-based liquid nitrogen experimentation. The test rig consists of an insulated tank of approximately 12.5 cubic ft in volume, which is supplied with liquid nitrogen from a 300 gal dewar via a vacuum jacketed piping system. The test tank is fitted with pressure and temperature measuring instrumentation, and with two view ports which allow visual observation of test conditions. To demonstrate the capabilities of the facility, the initial test program is briefly described. The objective of the test program is to measure the condensation rate by injecting liquid nitrogen as a subcooled spray into the ullage of a tank 50 percent full of liquid nitrogen at saturated conditions. The condensation rate of the nitrogen vapor on the subcooled spray can be analytically modeled, and results validated and corrected by experimentally measuring the vapor condensation on liquid sprays.

  4. Description of liquid nitrogen experimental test facility

    NASA Technical Reports Server (NTRS)

    Jurns, J. M.; Jacobs, R. E.; Saiyed, N. H.

    1992-01-01

    The Liquid Nitrogen Test Facility is a unique test facility for ground-based liquid nitrogen experimentation. The test rig consists of an insulated tank of approximately 12.5 cubic ft in volume, which is supplied with liquid nitrogen from a 300 gal dewar via a vacuum jacketed piping system. The test tank is fitted with pressure and temperature measuring instrumentation, and with two view ports which allow visual observation of test conditions. To demonstrate the capabilities of the facility, the initial test program is briefly described. The objective of the test program is to measure the condensation rate by injecting liquid nitrogen as a subcooled spray into the ullage of a tank 50 percent full of liquid nitrogen at saturated conditions. The condensation rate of the nitrogen vapor on the subcooled spray can be analytically modeled, and results validated and corrected by experimentally measuring the vapor condensation on liquid sprays.

  5. Experimental analysis of in plane shear behaviour of woven composite reinforcements. Influence of tensions

    NASA Astrophysics Data System (ADS)

    Launay, Jean; Hivet, Gilles; Vu Duong, Ahn; Boisse, Philippe

    2007-04-01

    Two tests are mainly used to identify the shear behavior of fabrics. The "picture frame" which uses a lozenge framework made of four rigid and articulated bars and the "bias test" which is a tensile test on a sample with initially a 45° angle between the yarns and the edges. The picture frame test is the more commonly used because the whole specimen is theoretically in a pure shear state. Nevertheless the absence of tension in the woven reinforcement supposes a perfect alignment of fibres and positioning of the clamping point with regards to the framework articulations. In addition, it is often necessary in practice to impose an initial tension which is not quantified and whose consequences are ignored in the classical picture frame test. An experimental device making it possible to measure the tensions during the test is carried out. Different types of teste on different fabrics have been performed. Results presented here concern a twintex fabric that has been selected for a shear benchmark Thanks to this device, it is shown that tensions play an important role in plane shear behaviour.

  6. ED14-0338-081

    NASA Image and Video Library

    2014-11-06

    Initial flight-testing of the ACTE followed extensive wind tunnel experiments. For the first phase of ACTE flights, the experimental control surfaces were locked at a specified setting. Varied flap settings on subsequent tests are now demonstrating the capability of the flexible surfaces under actual flight conditions.

  7. Quiet Clean Short-haul Experimental Engine (QCSEE). Under-The-Wing (UTW) engine boilerplate nacelle test report. Volume 3: Mechanical performance

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Results of initial tests of the under the wing experimental engine and boilerplate nacelle are presented. The mechanical performance of the engine is reported with emphasis on the advanced technology components. Technology elements of the propulsion system covered include: system dynamics, composite fan blades, reduction gear, lube and accessory drive system, fan frame, inlet, core cowl cooling, fan exhaust nozzle, and digital control system.

  8. 77 FR 485 - Wind Plant Performance-Public Meeting on Modeling and Testing Needs for Complex Air Flow...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-05

    ... modeling needs and experimental validation techniques for complex flow phenomena in and around off- shore... experimental validation. Ultimately, research in this area may lead to significant improvements in wind plant... meeting will consist of an initial plenary session in which invited speakers will survey available...

  9. Collaborative Philosophical Enquiry for School Children: Socio-Emotional Effects at 11 to 12 Years

    ERIC Educational Resources Information Center

    Trickey, S.; Topping, K. J.

    2006-01-01

    Two measures were used to investigate the socioemotional effects of collaborative philosophical enquiry on children aged 11 at pre-test in five experimental and three control primary (elementary) school mainstream classes. Experimental teachers received initial and follow-up professional development. In a pre-post controlled design, experimental…

  10. Advanced oxidation of commercial herbicides mixture: experimental design and phytotoxicity evaluation.

    PubMed

    López, Alejandro; Coll, Andrea; Lescano, Maia; Zalazar, Cristina

    2017-05-05

    In this work, the suitability of the UV/H 2 O 2 process for commercial herbicides mixture degradation was studied. Glyphosate, the herbicide most widely used in the world, was mixed with other herbicides that have residual activity as 2,4-D and atrazine. Modeling of the process response related to specific operating conditions like initial pH and initial H 2 O 2 to total organic carbon molar ratio was assessed by the response surface methodology (RSM). Results have shown that second-order polynomial regression model could well describe and predict the system behavior within the tested experimental region. It also correctly explained the variability in the experimental data. Experimental values were in good agreement with the modeled ones confirming the significance of the model and highlighting the success of RSM for UV/H 2 O 2 process modeling. Phytotoxicity evolution throughout the photolytic degradation process was checked through germination tests indicating that the phytotoxicity of the herbicides mixture was significantly reduced after the treatment. The end point for the treatment at the operating conditions for maximum TOC conversion was also identified.

  11. Characterizing Fracturing of Clay-Rich Lower Watrous Rock: From Laboratory Experiments to Nonlocal Damage-Based Simulations

    NASA Astrophysics Data System (ADS)

    Guy, N.; Seyedi, D. M.; Hild, F.

    2018-06-01

    The work presented herein aims at characterizing and modeling fracturing (i.e., initiation and propagation of cracks) in a clay-rich rock. The analysis is based on two experimental campaigns. The first one relies on a probabilistic analysis of crack initiation considering Brazilian and three-point flexural tests. The second one involves digital image correlation to characterize crack propagation. A nonlocal damage model based on stress regularization is used for the simulations. Two thresholds both based on regularized stress fields are considered. They are determined from the experimental campaigns performed on Lower Watrous rock. The results obtained with the proposed approach are favorably compared with the experimental results.

  12. Experimental Model of Biofilm Implant-Related Osteomyelitis To Test Combination Biomaterials Using Biofilms as Initial Inocula

    PubMed Central

    Williams, Dustin L.; Haymond, Bryan S.; Woodbury, Kassie L.; Beck, J. Peter; Moore, David E.; Epperson, R. Tyler; Bloebaum, Roy D.

    2012-01-01

    Currently, the majority of animal models that are used to study biofilm-related infections utilize planktonic bacterial cells as initial inocula to produce positive signals of infection in biomaterials studies. However, the use of planktonic cells has potentially led to inconsistent results in infection outcomes. In this study, well-established biofilms of methicillin-resistant Staphylococcus aureus (MRSA) were grown and used as initial inocula in an animal model of a Type IIIB open fracture. The goal of the work was to establish, for the first time, a repeatable model of biofilm implant-related osteomyelitis wherein biofilms were used as initial inocula to test combination biomaterials. Results showed that 100% of animals that were treated with biofilms developed osteomyelitis, whereas 0% of animals not treated with biofilm developed infection. The development of this experimental model may lead to an important shift in biofilm and biomaterials research by showing that when biofilms are used as initial inocula, they may provide additional insights into how biofilm-related infections in the clinic develop and how they can be treated with combination biomaterials to eradicate and/or prevent biofilm formation. PMID:22492534

  13. Experimental model of biofilm implant-related osteomyelitis to test combination biomaterials using biofilms as initial inocula.

    PubMed

    Williams, Dustin L; Haymond, Bryan S; Woodbury, Kassie L; Beck, J Peter; Moore, David E; Epperson, R Tyler; Bloebaum, Roy D

    2012-07-01

    Currently, the majority of animal models that are used to study biofilm-related infections use planktonic bacterial cells as initial inocula to produce positive signals of infection in biomaterials studies. However, the use of planktonic cells has potentially led to inconsistent results in infection outcomes. In this study, well-established biofilms of methicillin-resistant Staphylococcus aureus were grown and used as initial inocula in an animal model of a Type IIIB open fracture. The goal of the work was to establish, for the first time, a repeatable model of biofilm implant-related osteomyelitis, wherein biofilms were used as initial inocula to test combination biomaterials. Results showed that 100% of animals that were treated with biofilms developed osteomyelitis, whereas 0% of animals not treated with biofilm developed infection. The development of this experimental model may lead to an important shift in biofilm and biomaterials research by showing that when biofilms are used as initial inocula, they may provide additional insights into how biofilm-related infections in the clinic develop and how they can be treated with combination biomaterials to eradicate and/or prevent biofilm formation. Copyright © 2012 Wiley Periodicals, Inc.

  14. Inelastic response of metal matrix composites under biaxial loading

    NASA Technical Reports Server (NTRS)

    Mirzadeh, F.; Pindera, Marek-Jerzy; Herakovich, Carl T.

    1990-01-01

    Elements of the analytical/experimental program to characterize the response of silicon carbide titanium (SCS-6/Ti-15-3) composite tubes under biaxial loading are outlined. The analytical program comprises prediction of initial yielding and subsequent inelastic response of unidirectional and angle-ply silicon carbide titanium tubes using a combined micromechanics approach and laminate analysis. The micromechanics approach is based on the method of cells model and has the capability of generating the effective thermomechanical response of metal matrix composites in the linear and inelastic region in the presence of temperature and time-dependent properties of the individual constituents and imperfect bonding on the initial yield surfaces and inelastic response of (0) and (+ or - 45)sub s SCS-6/Ti-15-3 laminates loaded by different combinations of stresses. The generated analytical predictions will be compared with the experimental results. The experimental program comprises generation of initial yield surfaces, subsequent stress-strain curves and determination of failure loads of the SCS-6/Ti-15-3 tubes under selected loading conditions. The results of the analytical investigation are employed to define the actual loading paths for the experimental program. A brief overview of the experimental methodology is given. This includes the test capabilities of the Composite Mechanics Laboratory at the University of Virginia, the SCS-6/Ti-15-3 composite tubes secured from McDonnell Douglas Corporation, a text fixture specifically developed for combined axial-torsional loading, and the MTS combined axial-torsion loader that will be employed in the actual testing.

  15. Experimental and numerical investigation of the nonlinear dynamics of compliant mechanisms for deployable structures

    NASA Astrophysics Data System (ADS)

    Dewalque, Florence; Schwartz, Cédric; Denoël, Vincent; Croisier, Jean-Louis; Forthomme, Bénédicte; Brüls, Olivier

    2018-02-01

    This paper studies the dynamics of tape springs which are characterised by a highly geometrical nonlinear behaviour including buckling, the formation of folds and hysteresis. An experimental set-up is designed to capture these complex nonlinear phenomena. The experimental data are acquired by the means of a 3D motion analysis system combined with a synchronised force plate. Deployment tests show that the motion can be divided into three phases characterised by different types of folds, frequencies of oscillation and damping behaviours. Furthermore, the reproducibility quality of the dynamic and quasi-static results is validated by performing a large number of tests. In parallel, a nonlinear finite element model is developed. The required model parameters are identified based on simple experimental tests such as static deformed configurations and small amplitude vibration tests. In the end, the model proves to be well correlated with the experimental results in opposite sense bending, while in equal sense, both the experimental set-up and the numerical model are particularly sensitive to the initial conditions.

  16. Multibody modeling and verification

    NASA Technical Reports Server (NTRS)

    Wiens, Gloria J.

    1989-01-01

    A summary of a ten week project on flexible multibody modeling, verification and control is presented. Emphasis was on the need for experimental verification. A literature survey was conducted for gathering information on the existence of experimental work related to flexible multibody systems. The first portion of the assigned task encompassed the modeling aspects of flexible multibodies that can undergo large angular displacements. Research in the area of modeling aspects were also surveyed, with special attention given to the component mode approach. Resulting from this is a research plan on various modeling aspects to be investigated over the next year. The relationship between the large angular displacements, boundary conditions, mode selection, and system modes is of particular interest. The other portion of the assigned task was the generation of a test plan for experimental verification of analytical and/or computer analysis techniques used for flexible multibody systems. Based on current and expected frequency ranges of flexible multibody systems to be used in space applications, an initial test article was selected and designed. A preliminary TREETOPS computer analysis was run to ensure frequency content in the low frequency range, 0.1 to 50 Hz. The initial specifications of experimental measurement and instrumentation components were also generated. Resulting from this effort is the initial multi-phase plan for a Ground Test Facility of Flexible Multibody Systems for Modeling Verification and Control. The plan focusses on the Multibody Modeling and Verification (MMV) Laboratory. General requirements of the Unobtrusive Sensor and Effector (USE) and the Robot Enhancement (RE) laboratories were considered during the laboratory development.

  17. 48 CFR 252.235-7003 - Frequency authorization.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Officer during the initial planning, experimental, or developmental phase of contract performance. (c) The... development, production, construction, testing, or operation of a device for which a radio frequency...

  18. 48 CFR 252.235-7003 - Frequency authorization.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Officer during the initial planning, experimental, or developmental phase of contract performance. (c) The... development, production, construction, testing, or operation of a device for which a radio frequency...

  19. 48 CFR 252.235-7003 - Frequency authorization.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Officer during the initial planning, experimental, or developmental phase of contract performance. (c) The... development, production, construction, testing, or operation of a device for which a radio frequency...

  20. Investigation on Bond-Slip Behavior of Z-Pin Interfaces in X-Cor® Sandwich Structures Using Z-Pin Pull-Out Test

    NASA Astrophysics Data System (ADS)

    Shan, Hangying; Xiao, Jun; Chu, Qiyi

    2018-05-01

    The Z-Pin interfacial bond properties play an important role in the structural performance of X-Cor® sandwich structures. This paper presents an experimental investigation on bond-slip behavior of Z-Pin interfaces using Z-Pin pull-out test. Based on the experimental data the whole Z-Pin pull-out process consists of three stages: initial bonding, debonding and frictional sliding. Comparative experimental study on the influence of design parameters on bond-slip behavior of Z-Pin interfaces has also been performed. Numerical analyses were conducted with the ABAQUS finite element (FE) program to simulate the Z-Pins bond-slip response of the pull-out test. The Z-Pins interfacial bond-slip behavior was implemented using nonlinear spring elements characterized with the constitutive relation from experimental results. Numerical results were validated by comparison with experimental data, and reasonably good agreement was achieved between experimental and analytical pull-out force-slip curves.

  1. Comparative analysis of international standards for the fatigue testing of posterior spinal fixation systems: the importance of preload in ISO 12189.

    PubMed

    La Barbera, Luigi; Ottardi, Claudia; Villa, Tomaso

    2015-10-01

    Preclinical evaluation of the mechanical reliability of fixation devices is a mandatory activity before their introduction into market. There are two standardized protocols for preclinical testing of spinal implants. The American Society for Testing Materials (ASTM) recommends the F1717 standard, which describes a vertebrectomy condition that is relatively simple to implement, whereas the International Organization for Standardization (ISO) suggests the 12189 standard, which describes a more complex physiological anterior support-based setup. Moreover, ASTM F1717 is nowadays well established, whereas ISO 12189 has received little attention: A few studies tried to accurately describe the ISO experimental procedure through numeric models, but these studies totally neglect the recommended precompression step. This study aimed to build up a reliable, validated numeric model capable of describing the stress on the rods of a spinal fixator assembled according to ISO 12189 standard procedure. Such a model would more adequately represent the in vitro testing condition. This study used finite element (FE) simulations and experimental validation testing. An FE model of the ISO setup was built to calculate the stress on the rods. Simulation was validated by comparison with experimental strain gauges measurements. The same fixator has been previously virtually mounted in an L2-L4 FE model of the lumbar spine, and stresses in the rods were calculated when the spine was subjected to physiological forces and moments. The comparison between the FE predictions and experimental measurements is in good agreement, thus confirming the suitability of the FE method to evaluate the stresses in the device. The initial precompression induces a significant extension of the assembled construct. As the applied load increases, the initial extension is gradually compensated, so that at peak load the rods are bent in flexion: The final stress value predicted is thus reduced to about 50%, if compared with the previous model where the precompression was not considered. Neglecting the initial preload due to the assembly of the overall construct according to ISO 12189 standard could lead to an overestimation of the stress on the rods up to 50%. To correctly describe the state of stress on the posterior spinal fixator, tested according to the ISO procedure, it is important to take into account the initial preload due to the assembly of the overall construct. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Energy Efficiency and Sustainability of Different Building Structures in Latvian Climate

    NASA Astrophysics Data System (ADS)

    Jakovičs, A.; Gendelis, S.; Bandeniece, L.

    2015-11-01

    Five experimental test buildings have been built in Riga, Latvia. They are identical except external walls for which different mainly regional building materials are used. Calculated U-values of the other walls, floor and ceiling are the same for each test building. Initial moisture influences the relative humidity of indoor air, which can be higher in the initial time period; as a result, heat transmittances are also very different and cause different heating/cooling energy consumption. Overheating risk in summer exists for test buildings with the smallest thermal inertia. Both summer and heating seasons have been analysed and differences between five test houses have been discussed in details.

  3. Fracture Test Methods for Plastically Responding COPV Liners

    NASA Technical Reports Server (NTRS)

    Dawicke, David S.; Lewis, Joseph C.

    2009-01-01

    An experimental procedure for evaluating the validity of using uniaxial tests to provide a conservative bound on the fatigue crack growth rate behavior small cracks in bi-axially loaded Composite Overwrapped Pressure Vessel (COPV) liners is described. The experimental procedure included the use of a laser notch to quickly generate small surface fatigue cracks with the desired size and aspect ratios. An out-of-plane constraint system was designed to allow fully reversed, fully plastic testing of thin sheet uniaxial coupons. Finally, a method was developed to determine to initiate small cracks in the liner of COPVs.

  4. Flow induction by pressure forces

    NASA Technical Reports Server (NTRS)

    Garris, C. A.; Toh, K. H.; Amin, S.

    1992-01-01

    A dual experimental/computational approach to the fluid mechanics of complex interactions that take place in a rotary-jet ejector is presented. The long-range goal is to perform both detailed flow mapping and finite element computational analysis. The described work represents an initial finding on the experimental mapping program. Test results on the hubless rotary-jet are discussed.

  5. Effects of Aggregation on Blood Sedimentation and Conductivity

    PubMed Central

    Zhbanov, Alexander; Yang, Sung

    2015-01-01

    The erythrocyte sedimentation rate (ESR) test has been used for over a century. The Westergren method is routinely used in a variety of clinics. However, the mechanism of erythrocyte sedimentation remains unclear, and the 60 min required for the test seems excessive. We investigated the effects of cell aggregation during blood sedimentation and electrical conductivity at different hematocrits. A sample of blood was drop cast into a small chamber with two planar electrodes placed on the bottom. The measured blood conductivity increased slightly during the first minute and decreased thereafter. We explored various methods of enhancing or retarding the erythrocyte aggregation. Using experimental measurements and theoretical calculations, we show that the initial increase in blood conductivity was indeed caused by aggregation, while the subsequent decrease in conductivity resulted from the deposition of erythrocytes. We present a method for calculating blood conductivity based on effective medium theory. Erythrocytes are modeled as conducting spheroids surrounded by a thin insulating membrane. A digital camera was used to investigate the erythrocyte sedimentation behavior and the distribution of the cell volume fraction in a capillary tube. Experimental observations and theoretical estimations of the settling velocity are provided. We experimentally demonstrate that the disaggregated cells settle much slower than the aggregated cells. We show that our method of measuring the electrical conductivity credibly reflected the ESR. The method was very sensitive to the initial stage of aggregation and sedimentation, while the sedimentation curve for the Westergren ESR test has a very mild slope in the initial time. We tested our method for rapid estimation of the Westergren ESR. We show a correlation between our method of measuring changes in blood conductivity and standard Westergren ESR method. In the future, our method could be examined as a potential means of accelerating ESR tests in clinical practice. PMID:26047511

  6. Study of thermocline development inside a dual-media storage tank at the beginning of dynamic processes

    NASA Astrophysics Data System (ADS)

    Esence, Thibaut; Bayón, Rocío; Bruch, Arnaud; Rojas, Esther

    2017-06-01

    This work presents some of the experimental results obtained during a test campaign performed at the STONE facility of CEA-Grenoble in collaboration with CIEMAT-PSA supported by both the SFERA-II and the STAGE-STE project. This installation consists of a thermocline tank with thermal oil and rock/sand filler and the tests aimed to study the development of the temperature profile inside the tank at the beginning of charge/discharge processes. The investigation of how this profile is created and which is its dependence on the experimental parameters is crucial for predicting the behavior of a dual-media thermocline tank. Tests have been performed for dynamic processes from initial states with constant uniform temperature or with a thermal gradient already present due to a partial thermocline zone extraction in the former process. Tests at different fluid velocities and temperatures have been carried out as well, in order to evaluate the influence of operating conditions. When a dynamic process of charge or discharge is started, the development of the thermal front is very sharp and localized at tank top or bottom if initial tank temperature is uniform, whereas it is less pronounced if the test begins from a non-thermally uniform initial state. In terms of operating conditions, it has been observed that the development of the thermocline thermal front is independent not only of the fluid velocity but also of its temperatures, within the working ranges here considered. Due to these experimental results, it will be possible to improve simulation models for thermocline tanks and hence to predict their behavior more accurately, especially when they are implemented in annual simulations of CSP plants.

  7. Restructurable VLSI Program

    DTIC Science & Technology

    1981-03-31

    logic testing element and a concomitant testability criterion ideally suited to dynamic circuit applications and appro- priate for automatic computer...making connections automatically . PF is an experimental feature which provides users with only four different chip sizes (full, half, quarter, and eighth...initial solution is found constructively which is improved by pair-wise swapping. Results show, however, that the constructive initial sorter , which

  8. Knowledge Impact of a US-Based Tobacco Prevention Curriculum among Tanzanian Children

    ERIC Educational Resources Information Center

    St. Germain, Paige; Lucas, Frances L.; Williams Wilson, Miriam J.; Maegga, Bertha Tsingay A.; Miesfeldt, Susan

    2017-01-01

    Purpose: Tobacco use is a major public health issue in developing countries, with substantial initial exposure in childhood. School-based educational resources promise to reduce tobacco initiation and experimentation among children from low-income countries. Research in this area is scant. The study goal was to test the impact of an evidence-based…

  9. Experimental Estimates of the Impacts of Class Size on Test Scores: Robustness and Heterogeneity

    ERIC Educational Resources Information Center

    Ding, Weili; Lehrer, Steven F.

    2011-01-01

    Proponents of class size reductions (CSRs) draw heavily on the results from Project Student/Teacher Achievement Ratio to support their initiatives. Adding to the political appeal of these initiative are reports that minority and economically disadvantaged students received the largest benefits from smaller classes. We extend this research in two…

  10. Initial test results using the GEOS-3 engineering model altimeter

    NASA Technical Reports Server (NTRS)

    Hayne, G. S.; Clary, J. B.

    1977-01-01

    Data from a series of experimental tests run on the engineering model of the GEOS 3 radar altimeter using the Test and Measurement System (TAMS) designed for preflight testing of the radar altimeter are presented. These tests were conducted as a means of preparing and checking out a detailed test procedure to be used in running similar tests on the GEOS 3 protoflight model altimeter systems. The test procedures and results are also included.

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

    Mattes, R.H.; Bacho, A.; Wade, L.V.

    The Lake Lynn Laboratory is a multipurpose mining research laboratory operated by the Bureau of Mines and located in Fairchance, Pa. It consists of both surface and underground facilities. The initial focus of the facility, scheduled for full operation in fall 1982, will be on the problems of fires and explosions in mines. The initial experimental explosion was fired on March 3, 1982. The intent of this document is to provide the reader with detailed information on the physical capabilities of the Lake Lynn Laboratory. Subsequent publications will focus on the capabilities of Lake Lynn as compared with those ofmore » other similar facilities worldwide, and a comparison of initial explosion test results realized at Lake Lynn and comparable results from the Bruceton Experimental Mines.« less

  12. The Anatomy of Action Systems: Task Differentiation When Learning an EMG Controlled Game

    PubMed Central

    van Dijk, Ludger; Heerschop, Anniek; van der Sluis, Corry K.; Bongers, Raoul M.

    2016-01-01

    This study aims to determine to what extent the task for an action system in its initial development relies on functional and anatomical components. Fifty-two able-bodied participants were randomly assigned to one of three experimental groups or to a control group. As a pre- and post-test all groups performed a computer game with the same goal and using the same musculature. One experimental group also trained to perform this test, while the other two experimental groups learned to perform a game that differed either in its goal or in the musculature used. The observed change in accuracy indicated that retaining the goal of the task or the musculature used equally increased transfer performance relative to controls. Conversely, changing either the goal or the musculature equally decreased transfer relative to training the test. These results suggest that in the initial development of an action system, the task to which the system pertains is not specified solely by either the goal of the task or the anatomical structures involved. It is suggested that functional specificity and anatomical dependence might equally be outcomes of continuously differentiating activity. PMID:28018278

  13. Turbine engine rotor health monitoring evaluation by means of finite element analyses and spin tests data

    NASA Astrophysics Data System (ADS)

    Abdul-Aziz, Ali; Woike, Mark R.; Clem, Michelle; Baaklini, George Y.

    2014-04-01

    Generally, rotating engine components undergo high centrifugal loading environment which subject them to various types of failure initiation mechanisms. Health monitoring of these components is a necessity and is often challenging to implement. This is primarily due to numerous factors including the presence of scattered loading conditions, flaw sizes, component geometry and materials properties, all which hinder the simplicity of applying health monitoring applications. This paper represents a summary work of combined experimental and analytical modeling that included data collection from a spin test experiment of a rotor disk addressing the aforementioned durability issues. It further covers presentation of results obtained from a finite element modeling study to characterize the structural durability of a cracked rotor as it relates to the experimental findings. The experimental data include blade tip clearance, blade tip timing and shaft displacement measurements. The tests were conducted at the NASA Glenn Research Center's Rotordynamics Laboratory, a high precision spin rig. The results are evaluated and examined to determine their significance on the development of a health monitoring system to pre-predict cracks and other anomalies and to assist in initiating a supplemental physics based fault prediction analytical model.

  14. Construction and Initial Tests of MAIZE: 1 MA LTD-Driven Z-Pinch *

    NASA Astrophysics Data System (ADS)

    Gilgenbach, R. M.; Gomez, M. R.; Zier, J. C.; Tang, W.; French, D. M.; Lau, Y. Y.; Mazarakis, M. G.; Cuneo, M. E.; Johnston, M. D.; Oliver, B. V.; Mehlhorn, T. A.; Kim, A. A.; Sinebryukhov, V. A.

    2008-11-01

    We report construction and initial testing of a 1-MA Linear Transformer Driver (LTD), The Michigan Accelerator for Inductive Z-pinch Experiments, (MAIZE). This machine, the first of its type to reach the USA, is based on the joint HCEI, Sandia Laboratories, and UM development effort. The compact LTD uses 80 capacitors and 40 spark gap switches, in 40 ``bricks'', to deliver 1 MA, 100 kV pulses with 70 ns risetime into a matched resistive load. Test results will be presented for a single brick and the full LTD. Design and construction will be presented of a low-inductance MITL. Experimental research programs under design and construction at UM include: a) Studies of Magneto-Raleigh-Taylor Instability of planar foils, and b) Vacuum convolute studies including cathode and anode plasma. Theory and simulation results will be presented for these planned experiments. Initial experimental designs and moderate-current feasibility experiments will be discussed. *Research supported by U. S. DoE through Sandia National Laboratories award document numbers 240985, 768225, 790791 and 805234 to the UM. MRG supported by NNSA Fellowship and JCZ supported by NPSC Fellowship / Sandia National Labs.

  15. Evaluation of high temperature structural adhesives for extended service, phase 4

    NASA Technical Reports Server (NTRS)

    Hendricks, C. L.; Hill, S. G.; Hale, J. N.

    1985-01-01

    The evaluation of three phenylquinoxaline polymers as high temperature structural adhesives is presented. These included an experimental crisskubjabke oiktner (X-PQ) and two experimental materials (PPQ-2501) and (PPQ-HC). Lap shear, crack extension, and climing drum peel specimens were fabricated from all three polymers, and tested after thermal, combined thermal/humidity, and stressed Skydrol exposure. All three polymers generally performed well as adhesives at initial test temperatures from 219K (-67 F) to 505K (450 F) and after humidity exposure. The 644K (700 F) cured test specimens exhibited superior Skydrol resistance and thermal stability at 505K (450 F) when compared to the 602K (625 F) cured test specimens.

  16. Experimental verification of PSM polarimetry: monitoring polarization at 193nm high-NA with phase shift masks

    NASA Astrophysics Data System (ADS)

    McIntyre, Gregory; Neureuther, Andrew; Slonaker, Steve; Vellanki, Venu; Reynolds, Patrick

    2006-03-01

    The initial experimental verification of a polarization monitoring technique is presented. A series of phase shifting mask patterns produce polarization dependent signals in photoresist and are capable of monitoring the Stokes parameters of any arbitrary illumination scheme. Experiments on two test reticles have been conducted. The first reticle consisted of a series of radial phase gratings (RPG) and employed special apertures to select particular illumination angles. Measurement sensitivities of about 0.3 percent of the clear field per percent change in polarization state were observed. The second test reticle employed the more sensitive proximity effect polarization analyzers (PEPA), a more robust experimental setup, and a backside pinhole layer for illumination angle selection and to enable characterization of the full illuminator. Despite an initial complication with the backside pinhole alignment, the results correlate with theory. Theory suggests that, once the pinhole alignment is corrected in the near future, the second reticle should achieve a measurement sensitivity of about 1 percent of the clear field per percent change in polarization state. This corresponds to a measurement of the Stokes parameters after test mask calibration, to within about 0.02 to 0.03. Various potential improvements to the design, fabrication of the mask, and experimental setup are discussed. Additionally, to decrease measurement time, a design modification and double exposure technique is proposed to enable electrical detection of the measurement signal.

  17. Electron cyclotron thruster new modeling results preparation for initial experiments

    NASA Technical Reports Server (NTRS)

    Hooper, E. Bickford

    1993-01-01

    The following topics are discussed: a whistler-based electron cyclotron resonance heating (ECRH) thruster; cross-field coupling in the helicon approximation; wave propagation; wave structure; plasma density; wave absorption; the electron distribution function; isothermal and adiabatic plasma flow; ECRH thruster modeling; a PIC code model; electron temperature; electron energy; and initial experimental tests. The discussion is presented in vugraph form.

  18. Does Input Enhancement Work for Learning Politeness Strategies?

    ERIC Educational Resources Information Center

    Khatib, Mohammad; Safari, Mahmood

    2013-01-01

    The present study investigated the effect of input enhancement on the acquisition of English politeness strategies by intermediate EFL learners. Two groups of freshman English majors were randomly assigned to the experimental (enhanced input) group and the control (mere exposure) group. Initially, a TOEFL test and a discourse completion test (DCT)…

  19. Definition study of a Variable Cycle Experimental Engine (VCEE) and associated test program and test plan

    NASA Technical Reports Server (NTRS)

    Allan, R. D.

    1978-01-01

    The Definition Study of a Variable Cycle Experimental Engine (VCEE) and Associated Test Program and Test Plan, was initiated to identify the most cost effective program for a follow-on to the AST Test Bed Program. The VCEE Study defined various subscale VCE's based on different available core engine components, and a full scale VCEE utilizing current technology. The cycles were selected, preliminary design accomplished and program plans and engineering costs developed for several program options. In addition to the VCEE program plans and options, a limited effort was applied to identifying programs that could logically be accomplished on the AST Test Bed Program VCE to extend the usefulness of this test hardware. Component programs were provided that could be accomplished prior to the start of a VCEE program.

  20. Experimental instrumentation system for the Phased Array Mirror Extendible Large Aperture (PAMELA) test program

    NASA Technical Reports Server (NTRS)

    Boykin, William H., Jr.

    1993-01-01

    Adaptive optics are used in telescopes for both viewing objects with minimum distortion and for transmitting laser beams with minimum beam divergence and dance. In order to test concepts on a smaller scale, NASA MSFC is in the process of setting up an adaptive optics test facility with precision (fraction of wavelengths) measurement equipment. The initial system under test is the adaptive optical telescope called PAMELA (Phased Array Mirror Extendible Large Aperture). Goals of this test are: assessment of test hardware specifications for PAMELA application and the determination of the sensitivities of instruments for measuring PAMELA (and other adaptive optical telescopes) imperfections; evaluation of the PAMELA system integration effort and test progress and recommended actions to enhance these activities; and development of concepts and prototypes of experimental apparatuses for PAMELA.

  1. Experimental and numerical investigations on freeze-drying of porous media with prebuilt porosity

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Yang, Jing; Hu, Dapeng; Pan, Yanqiu; Wang, Shihao; Chen, Guohua

    2018-05-01

    Freeze-drying of initially porous frozen material was investigated aimed at improving the process economics by reducing drying time and raising productivity. Experimental results showed that freeze-drying can be significantly enhanced by the frozen material with prebuilt porosity, and about 31% of drying time can be saved compared with the conventionally solid frozen material under the tested operating conditions. A multiphase transport model was formulated based on the local mass non-equilibrium assumption. Numerical results showed excellent agreements between measured and predicted drying curves. Analyses of saturation and temperature profiles displayed that volumetric sublimation-desorption can occur for the initially porous frozen material.

  2. Socialisation scheme with a high staff-patient ratio.

    PubMed

    Hollander, D; Rao, V B; McManoman, E; Harrington, N; Weeks, A; Mann, A

    1981-01-01

    Six months after a comprehensive socialisation scheme began, a prospective controlled study was carried out. The patients were tested in three practical sections - Cooking; Maintenance of Home and Clothing; Other Skills (eg. form-filling); and with a Questionnaire. Forty-eight members of an experimental group received socialisation training after initial testing. They and the 20 controls who did not undergo training were re-evaluated three months later. There was no significant difference between the groups in their initial scores. On retesting, the experimental group showed a significant improvement in Cooking (p less than 0.001), Home Maintenance (p less than 0.001) and the Questionnaire (p less than 0.05). Analysis of the inter-group differences showed significant superiority of the experimental group in Cooking (p less than 0.05) and Home Maintenance (p less than 0.05). It is suggested that such a socialisation scheme be considered for inclusion alongside other rehabilitation services in psychiatric hospitals. The emphasis on a high staff-to-patient ratio and the breakdown of each task into smaller steps emerged as essential elements in the training programme.

  3. Influence of subsolvus thermomechanical processing on the low-cycle fatigue properties of haynes 230 alloy

    NASA Astrophysics Data System (ADS)

    Vecchio, Kenneth S.; Fitzpatrick, Michael D.; Klarstrom, Dwaine

    1995-03-01

    Strain-controlled low-cycle fatigue tests have been conducted in air at elevated temperature to determine the influence of subsolvus thermomechanical processing on the low-cycle fatigue (LCF) behavior of HAYNES 230 alloy. A series of tests at various strain ranges was conducted on material experimentally processed at 1121 °C, which is below the M23C6 carbide solvus temperature, and on material fully solution annealed at 1232 °C. A comparative strain-life analysis was performed on the LCF results, and the cyclic hardening/softening characteristics were examined. At 760 °C and 871 °C, the fatigue life of the experimental 230/1121 material was improved relative to the standard 230/1232 material up to a factor of 3. The fatigue life advantage of the experimental material was related primarily to a lower plastic (inelastic) strain amplitude response for a given imposed total strain range. It appears the increase in monotonic flow stress exhibited by the finer grain size experimental material has been translated into an increase in cyclic flow stress at the 760 °C and 871 °C test temperatures. Both materials exhibited entirely transgranular fatigue crack initiation and propagation modes at these temperatures. The LCF performance of the experimental material in tests performed at 982 °C was improved relative to the standard material up to a factor as high as 2. The life advantage of the 230/1121 material occurred despite having a larger plastic strain amplitude than the standard 230/1232 material for a given total strain range. Though not fully understood at present, it is suspected that this behavior is related to the deleterious influence of grain boundaries in the fatigue crack initiations of the standard processed material relative to the experimental material, and ultimately to differences in carbide morphology as a result of thermomechanical processing.

  4. 10 CFR 70.39 - Specific licenses for the manufacture or initial transfer of calibration or reference sources.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... and design; (iii) Details of the method of incorporation and binding of the plutonium in the source; (iv) Procedures for and results of prototype testing of sources, which are designed to contain more... experimental studies and tests, required by the Commission to facilitate a determination of the safety of the...

  5. Effects of Goal-Setting Skills on Students'academic Performance in English Language in Enugu Nigeria

    ERIC Educational Resources Information Center

    Abe, Iyabo Idowu; Ilogu, Guy Chibuzoh; Madueke, Ify Louisa

    2014-01-01

    The study investigated the effectiveness of goal-setting skills among Senior Secondary II students' academic performance in English language in Enugu Metropolis, Enugu state, Nigeria. Quasi-experimental pre-test, post-test control group design was adopted for the study. The initial sample was 147 participants (male and female) Senior Secondary…

  6. Degradation mechanisms of bioresorbable polyesters. Part 2. Effects of initial molecular weight and residual monomer.

    PubMed

    Gleadall, Andrew; Pan, Jingzhe; Kruft, Marc-Anton; Kellomäki, Minna

    2014-05-01

    This paper presents an understanding of how initial molecular weight and initial monomer fraction affect the degradation of bioresorbable polymers in terms of the underlying hydrolysis mechanisms. A mathematical model was used to analyse the effects of initial molecular weight for various hydrolysis mechanisms including noncatalytic random scission, autocatalytic random scission, noncatalytic end scission or autocatalytic end scission. Different behaviours were identified to relate initial molecular weight to the molecular weight half-life and to the time until the onset of mass loss. The behaviours were validated by fitting the model to experimental data for molecular weight reduction and mass loss of samples with different initial molecular weights. Several publications that consider initial molecular weight were reviewed. The effect of residual monomer on degradation was also analysed, and shown to accelerate the reduction of molecular weight and mass loss. An inverse square root law relationship was found between molecular weight half-life and initial monomer fraction for autocatalytic hydrolysis. The relationship was tested by fitting the model to experimental data with various residual monomer contents. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  7. Methodological approaches to conducting pilot and proof tests on reverse-osmosis systems: Results of comparative studies

    NASA Astrophysics Data System (ADS)

    Panteleev, A. A.; Bobinkin, V. V.; Larionov, S. Yu.; Ryabchikov, B. E.; Smirnov, V. B.; Shapovalov, D. A.

    2017-10-01

    When designing large-scale water-treatment plants based on reverse-osmosis systems, it is proposed to conduct experimental-industrial or pilot tests for validated simulation of the operation of the equipment. It is shown that such tests allow establishing efficient operating conditions and characteristics of the plant under design. It is proposed to conduct pilot tests of the reverse-osmosis systems on pilot membrane plants (PMPs) and test membrane plants (TMPs). The results of a comparative experimental study of pilot and test membrane plants are exemplified by simulating the operating parameters of the membrane elements of an industrial plant. It is concluded that the reliability of the data obtained on the TMP may not be sufficient to design industrial water-treatment plants, while the PMPs are capable of providing reliable data that can be used for full-scale simulation of the operation of industrial reverse-osmosis systems. The test membrane plants allow simulation of the operating conditions of individual industrial plant systems; therefore, potential areas of their application are shown. A method for numerical calculation and experimental determination of the true selectivity and the salt passage are proposed. An expression has been derived that describes the functional dependence between the observed and true salt passage. The results of the experiments conducted on a test membrane plant to determine the true value of the salt passage of a reverse-osmosis membrane are exemplified by magnesium sulfate solution at different initial operating parameters. It is shown that the initial content of a particular solution component has a significant effect on the change in the true salt passage of the membrane.

  8. A new UK fission yield evaluation UKFY3.7

    NASA Astrophysics Data System (ADS)

    Mills, Robert William

    2017-09-01

    The JEFF neutron induced and spontaneous fission product yield evaluation is currently unchanged from JEFF-3.1.1, also known by its UK designation UKFY3.6A. It is based upon experimental data combined with empirically fitted mass, charge and isomeric state models which are then adjusted within the experimental and model uncertainties to conform to the physical constraints of the fission process. A new evaluation has been prepared for JEFF, called UKFY3.7, that incorporates new experimental data and replaces the current empirical models (multi-Gaussian fits of mass distribution and Wahl Zp model for charge distribution combined with parameter extrapolation), with predictions from GEF. The GEF model has the advantage that one set of parameters allows the prediction of many different fissioning nuclides at different excitation energies unlike previous models where each fissioning nuclide at a specific excitation energy had to be fitted individually to the relevant experimental data. The new UKFY3.7 evaluation, submitted for testing as part of JEFF-3.3, is described alongside initial results of testing. In addition, initial ideas for future developments allowing inclusion of new measurements types and changing from any neutron spectrum type to true neutron energy dependence are discussed. Also, a method is proposed to propagate uncertainties of fission product yields based upon the experimental data that underlies the fission yield evaluation. The covariance terms being determined from the evaluated cumulative and independent yields combined with the experimental uncertainties on the cumulative yield measurements.

  9. Validation of an Active Gear, Flexible Aircraft Take-off and Landing analysis (AGFATL)

    NASA Technical Reports Server (NTRS)

    Mcgehee, J. R.

    1984-01-01

    The results of an analytical investigation using a computer program for active gear, flexible aircraft take off and landing analysis (AGFATL) are compared with experimental data from shaker tests, drop tests, and simulated landing tests to validate the AGFATL computer program. Comparison of experimental and analytical responses for both passive and active gears indicates good agreement for shaker tests and drop tests. For the simulated landing tests, the passive and active gears were influenced by large strut binding friction forces. The inclusion of these undefined forces in the analytical simulations was difficult, and consequently only fair to good agreement was obtained. An assessment of the results from the investigation indicates that the AGFATL computer program is a valid tool for the study and initial design of series hydraulic active control landing gear systems.

  10. Performance Improvement Through Indexing of Turbine Airfoils. Part 2; Numerical Simulation

    NASA Technical Reports Server (NTRS)

    Griffin, Lisa W.; Huber, Frank W.; Sharma, Om P.

    1996-01-01

    An experimental/analytical study has been conducted to determine the performance improvements achievable by circumferentially indexing succeeding rows of turbine stator airfoils. A series of tests was conducted to experimentally investigate stator wake clocking effects on the performance of the space shuttle main engine (SSME) alternate turbopump development (ATD) fuel turbine test article (TTA). The results from this study indicate that significant increases in stage efficiency can be attained through application of this airfoil clocking concept. Details of the experiment and its results are documented in part 1 of this paper. In order to gain insight into the mechanisms of the performance improvement, extensive computational fluid dynamics (CFD) simulations were executed. The subject of the present paper is the initial results from the CFD investigation of the configurations and conditions detailed in part 1 of the paper. To characterize the aerodynamic environments in the experimental test series, two-dimensional (2D), time accurate, multistage, viscous analyses were performed at the TTA midspan. Computational analyses for five different circumferential positions of the first stage stator have been completed. Details of the computational procedure and the results are presented. The analytical results verify the experimentally demonstrated performance improvement and are compared with data whenever possible. Predictions of time-averaged turbine efficiencies as well as gas conditions throughout the flow field are presented. An initial understanding of the turbine performance improvement mechanism based on the results from this investigation is described.

  11. Experimental investigation of ice slurry flow pressure drop in horizontal tubes

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

    Grozdek, Marino; Khodabandeh, Rahmatollah; Lundqvist, Per

    2009-01-15

    Pressure drop behaviour of ice slurry based on ethanol-water mixture in circular horizontal tubes has been experimentally investigated. The secondary fluid was prepared by mixing ethyl alcohol and water to obtain initial alcohol concentration of 10.3% (initial freezing temperature -4.4 C). The pressure drop tests were conducted to cover laminar and slightly turbulent flow with ice mass fraction varying from 0% to 30% depending on test conditions. Results from flow tests reveal much higher pressure drop for higher ice concentrations and higher velocities in comparison to the single phase flow. However for ice concentrations of 15% and higher, certain velocitymore » exists at which ice slurry pressure drop is same or even lower than for single phase flow. It seems that higher ice concentration delay flow pattern transition moment (from laminar to turbulent) toward higher velocities. In addition experimental results for pressure drop were compared to the analytical results, based on Poiseulle and Buckingham-Reiner models for laminar flow, Blasius, Darby and Melson, Dodge and Metzner, Steffe and Tomita for turbulent region and general correlation of Kitanovski which is valid for both flow regimes. For laminar flow and low buoyancy numbers Buckingham-Reiner method gives good agreement with experimental results while for turbulent flow best fit is provided with Dodge-Metzner and Tomita methods. Furthermore, for transport purposes it has been shown that ice mass fraction of 20% offers best ratio of ice slurry transport capability and required pumping power. (author)« less

  12. Modelling the graphite fracture mechanisms

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

    Jacquemoud, C.; Marie, S.; Nedelec, M.

    2012-07-01

    In order to define a design criterion for graphite components, it is important to identify the physical phenomena responsible for the graphite fracture, to include them in a more effective modelling. In a first step, a large panel of experiments have been realised in order to build up an important database; results of tensile tests, 3 and 4 point bending tests on smooth and notched specimens have been analysed and have demonstrated an important geometry related effects on the behavior up to fracture. Then, first simulations with an elastic or an elastoplastic bilinear constitutive law have not made it possiblemore » to simulate the experimental fracture stress variations with the specimen geometry, the fracture mechanisms of the graphite being at the microstructural scale. That is the reason why a specific F.E. model of the graphite structure has been developed in which every graphite grain has been meshed independently, the crack initiation along the basal plane of the particles as well as the crack propagation and coalescence have been modelled too. This specific model has been used to test two different approaches for fracture initiation: a critical stress criterion and two criteria of fracture mechanic type. They are all based on crystallographic considerations as a global critical stress criterion gave unsatisfactory results. The criteria of fracture mechanic type being extremely unstable and unable to represent the graphite global behaviour up to the final collapse, the critical stress criterion has been preferred to predict the results of the large range of available experiments, on both smooth and notched specimens. In so doing, the experimental observations have been correctly simulated: the geometry related effects on the experimental fracture stress dispersion, the specimen volume effects on the macroscopic fracture stress and the crack propagation at a constant stress intensity factor. In addition, the parameters of the criterion have been related to experimental observations: the local crack initiation stress of 8 MPa corresponds to the non-linearity apparition on the global behavior observed experimentally and the the maximal critical stress defined for the particle of 30 MPa is equivalent to the fracture stress of notched specimens. This innovative combination of crack modelling and a local crystallographic critical stress criterion made it possible to understand that cleavage initiation and propagation in the graphite microstructure was driven by a mean critical stress criterion. (authors)« less

  13. Stress corrosion crack initiation of Zircaloy-4 cladding tubes in an iodine vapor environment during creep, relaxation, and constant strain rate tests

    NASA Astrophysics Data System (ADS)

    Jezequel, T.; Auzoux, Q.; Le Boulch, D.; Bono, M.; Andrieu, E.; Blanc, C.; Chabretou, V.; Mozzani, N.; Rautenberg, M.

    2018-02-01

    During accidental power transient conditions with Pellet Cladding Interaction (PCI), the synergistic effect of the stress and strain imposed on the cladding by thermal expansion of the fuel, and corrosion by iodine released as a fission product, may lead to cladding failure by Stress Corrosion Cracking (SCC). In this study, internal pressure tests were conducted on unirradiated cold-worked stress-relieved Zircaloy-4 cladding tubes in an iodine vapor environment. The goal was to investigate the influence of loading type (constant pressure tests, constant circumferential strain rate tests, or constant circumferential strain tests) and test temperature (320, 350, or 380 °C) on iodine-induced stress corrosion cracking (I-SCC). The experimental results obtained with different loading types were consistent with each other. The apparent threshold hoop stress for I-SCC was found to be independent of the test temperature. SEM micrographs of the tested samples showed many pits distributed over the inner surface, which tended to coalesce into large pits in which a microcrack could initiate. A model for the time-to-failure of a cladding tube was developed using finite element simulations of the viscoplastic mechanical behavior of the material and a modified Kachanov's damage growth model. The times-to-failure predicted by this model are consistent with the experimental data.

  14. Friction testing of a new ligature

    NASA Astrophysics Data System (ADS)

    Mantel, Alison R.

    Objective. To determine if American Orthodontics' (AO) new, experimental ligature demonstrates less friction in vitro when compared to four other ligatures on the market. Methods. Four brackets were mounted on a custom metal fixture allowing an 0.018-in stainless steel wire attached to an opposite fixture with one bracket to be passively centered in the bracket slot. The wire was ligated to the bracket using one of five types of ligatures including the low friction test ligatures (AO), conventional ligatures (AO), Sili-Ties(TM) Silicone Infused Ties (GAC), SynergyRTM Low-Friction Ligatures (RMO), and SuperSlick ligatures (TP Orthodontics). Resistance to sliding was measured over a 7 mm sliding distance using a universal testing machine (Instron) with a 50 Newton load cell and a crosshead speed of 5 mm/min. The initial resistance to sliding (static) was determined by the peak force needed to initiate movement and the kinetic resistance to sliding was taken as the force at 5 mm of wire/bracket sliding. Fifteen unique tests were run for each ligature group in both dry and wet (saliva soaked for 24 hours with one drop prior to testing) conditions. Results. In the dry state, the SuperSlick ligature demonstrated more static friction than all of the other ligatures, while SuperSlick and Sili-Ties demonstrated more kinetic friction than the AO conventional, AO experimental and Synergy ligatures. In the wet condition, SuperSlick and the AO experimental ligature demonstrated the least static friction, followed by the AO conventional and Sili-Ties. The most static friction was observed with the Synergy ligatures. In the wet condition, the SuperSlick, AO experimental and AO conventional exhibited less kinetic friction than the Sili-Ties and Synergy ligatures. Conclusions. AO's experimental ligature exhibits less friction in the wet state than conventional ligatures, Sili-Ties and Synergy and is comparable to the SuperSlick ligature. These preliminary results suggest that the AO experimental ligature and the SuperSlick ligature create less friction, but direct conclusions regarding in vivo performance cannot be made and randomized controlled clinical trials are needed to determine if these ligatures have clinical significance in treatment efficiency.

  15. Compression of thick laminated composite beams with initial impact-like damage

    NASA Technical Reports Server (NTRS)

    Breivik, N. L.; Guerdal, Z.; Griffin, O. H., Jr.

    1992-01-01

    While the study of compression after impact of laminated composites has been under consideration for many years, the complexity of the damage initiated by low velocity impact has not lent itself to simple predictive models for compression strength. The damage modes due to non-penetrating, low velocity impact by large diameter objects can be simulated using quasi-static three-point bending. The resulting damage modes are less coupled and more easily characterized than actual impact damage modes. This study includes the compression testing of specimens with well documented initial damage states obtained from three-point bend testing. Compression strengths and failure modes were obtained for quasi-isotropic stacking sequences from 0.24 to 1.1 inches thick with both grouped and interspersed ply stacking. Initial damage prior to compression testing was divided into four classifications based on the type, extent, and location of the damage. These classifications are multiple through-thickness delaminations, isolated delamination, damage near the surface, and matrix cracks. Specimens from each classification were compared to specimens tested without initial damage in order to determine the effects of the initial damage on the final compression strength and failure modes. A finite element analysis was used to aid in the understanding and explanation of the experimental results.

  16. Numerical computation of Pop plot

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

    Menikoff, Ralph

    The Pop plot — distance-of-run to detonation versus initial shock pressure — is a key characterization of shock initiation in a heterogeneous explosive. Reactive burn models for high explosives (HE) must reproduce the experimental Pop plot to have any chance of accurately predicting shock initiation phenomena. This report describes a methodology for automating the computation of a Pop plot for a specific explosive with a given HE model. Illustrative examples of the computation are shown for PBX 9502 with three burn models (SURF, WSD and Forest Fire) utilizing the xRage code, which is the Eulerian ASC hydrocode at LANL. Comparisonmore » of the numerical and experimental Pop plot can be the basis for a validation test or as an aid in calibrating the burn rate of an HE model. Issues with calibration are discussed.« less

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

    Labby, Z.

    Physicists are often expected to have a solid grounding in experimental design and statistical analysis, sometimes filling in when biostatisticians or other experts are not available for consultation. Unfortunately, graduate education on these topics is seldom emphasized and few opportunities for continuing education exist. Clinical physicists incorporate new technology and methods into their practice based on published literature. A poor understanding of experimental design and analysis could Result in inappropriate use of new techniques. Clinical physicists also improve current practice through quality initiatives that require sound experimental design and analysis. Academic physicists with a poor understanding of design and analysismore » may produce ambiguous (or misleading) results. This can Result in unnecessary rewrites, publication rejection, and experimental redesign (wasting time, money, and effort). This symposium will provide a practical review of error and uncertainty, common study designs, and statistical tests. Instruction will primarily focus on practical implementation through examples and answer questions such as: where would you typically apply the test/design and where is the test/design typically misapplied (i.e., common pitfalls)? An analysis of error and uncertainty will also be explored using biological studies and associated modeling as a specific use case. Learning Objectives: Understand common experimental testing and clinical trial designs, what questions they can answer, and how to interpret the results Determine where specific statistical tests are appropriate and identify common pitfalls Understand the how uncertainty and error are addressed in biological testing and associated biological modeling.« less

  18. "Exploratory experimentation" as a probe into the relation between historiography and philosophy of science.

    PubMed

    Schickore, Jutta

    2016-02-01

    This essay utilizes the concept "exploratory experimentation" as a probe into the relation between historiography and philosophy of science. The essay traces the emergence of the historiographical concept "exploratory experimentation" in the late 1990s. The reconstruction of the early discussions about exploratory experimentation shows that the introduction of the concept had unintended consequences: Initially designed to debunk philosophical ideas about theory testing, the concept "exploratory experimentation" quickly exposed the poverty of our conceptual tools for the analysis of experimental practice. Looking back at a number of detailed analyses of experimental research, we can now appreciate that the concept of exploratory experimentation is too vague and too elusive to fill the desideratum whose existence it revealed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. The Influence of Juggling on Mental Rotation Performance in Children

    ERIC Educational Resources Information Center

    Jansen, Petra; Lange, Leonie F.; Heil, Martin

    2011-01-01

    Study aim: To assess the influence of juggling training on mental rotation performance in children. Material and methods: Two groups of girls aged 6-14 years were studied: experimental (EG; n = 26) and control (CG; n = 24). All girls solved a mental rotation task with 3-D block figures on computer screen (pre-test). After the initial test, EG…

  20. The Impact of a Community-Based Comprehensive Sex Education Program on Chinese Adolescents' Sex-Related Knowledge and Attitudes

    ERIC Educational Resources Information Center

    Wang, Bo; Meier, Ann; Shah, Iqbal; Li, Xiaoming

    2006-01-01

    The purpose of this study was to evaluate a community-based comprehensive sex education program among unmarried youth in China. The impact of the intervention on sexual knowledge, attitudes, and sexual initiation were assessed, using a pre-test post-test quasi-experimental research design. The program used six methods for providing sex-related…

  1. Structural Qualification of Composite Airframes

    NASA Technical Reports Server (NTRS)

    Kedward, Keith T.; McCarty, John E.

    1997-01-01

    The development of fundamental approaches for predicting failure and elongation characteristics of fibrous composites are summarized in this document. The research described includes a statistical formulation for individual fiber breakage and fragmentation and clustered fiber breakage, termed macrodefects wherein the aligned composite may represent a structural component such as a reinforcing bar element, a rebar. Experimental work conducted in support of the future exploitation of aligned composite rebar elements is also described. This work discusses the experimental challenges associated with rebar tensile test evaluation and describes initial numerical analyses performed in support of the experimental program.

  2. A method for validation of finite element forming simulation on basis of a pointwise comparison of distance and curvature

    NASA Astrophysics Data System (ADS)

    Dörr, Dominik; Joppich, Tobias; Schirmaier, Fabian; Mosthaf, Tobias; Kärger, Luise; Henning, Frank

    2016-10-01

    Thermoforming of continuously fiber reinforced thermoplastics (CFRTP) is ideally suited to thin walled and complex shaped products. By means of forming simulation, an initial validation of the producibility of a specific geometry, an optimization of the forming process and the prediction of fiber-reorientation due to forming is possible. Nevertheless, applied methods need to be validated. Therefor a method is presented, which enables the calculation of error measures for the mismatch between simulation results and experimental tests, based on measurements with a conventional coordinate measuring device. As a quantitative measure, describing the curvature is provided, the presented method is also suitable for numerical or experimental sensitivity studies on wrinkling behavior. The applied methods for forming simulation, implemented in Abaqus explicit, are presented and applied to a generic geometry. The same geometry is tested experimentally and simulation and test results are compared by the proposed validation method.

  3. Experimental and Numerical Investigations on Strength and Deformation Behavior of Cataclastic Sandstone

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Shao, J. F.; Xu, W. Y.; Zhao, H. B.; Wang, W.

    2015-05-01

    This work is devoted to characterization of the deformation and strength properties of cataclastic sandstones. Before conducting mechanical tests, the physical properties were first examined. These sandstones are characterized by a loose damaged microstructure and poorly cemented contacts. Then, a series of mechanical tests including hydrostatic, uniaxial, and triaxial compression tests were performed to study the mechanical strength and deformation of the sandstones. The results obtained show nonlinear stress-strain responses. The initial microcracks are closed at hydrostatic stress of 2.6 MPa, and the uniaxial compressive strength is about 0.98 MPa. Under triaxial compression, there is a clear transition from volumetric compressibility to dilatancy and a strong dependency on confining pressure. Based on the experimental evidence, an elastoplastic model is proposed using a linear yield function and a nonassociated plastic potential. There is good agreement between numerical results and experimental data.

  4. DETERMINING MINIMUM IGNITION ENERGIES AND QUENCHING DISTANCES OF DIFFICULT-TO-IGNITE COMPOUNDS

    EPA Science Inventory

    Minimum spark energies and corresponding flat-plate electrode quenching distances required to initiate propagation of a combustion wave have been experimentally measured for four flammable hydrofluorocarbon (HFC) refrigerants and propane using ASTM (American Society for Testing a...

  5. VALIDATION OF AN AVIAN TWO-GENERATION REPRODUCTION TEST: U.S. INITIATIVES

    EPA Science Inventory

    Documented effects to fish and wildlife populations, coupled with evidence from human poisonings, epidemiology, and experimental toxicology led to the formation of the Endocrine Disruptor Screening Program (EDSP) within the U.S. Environmental Protection Agency. EDSP main objectiv...

  6. 10 CFR 32.14 - Certain items containing byproduct material; requirements for license to apply or initially...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... maximum quantity of byproduct material in each product; (2) Details of construction and design of each... experimental studies and tests, required by the Commission to facilitate a determination of the safety of the...

  7. Initial studies of a flexural member composed of glass-fiber reinforced polyester resin.

    DOT National Transportation Integrated Search

    1973-01-01

    An investigation was conducted of the structural behavior of a flexural member composed entirely of glass-fiber reinforced polyester resin. Three experimental girders were fabricated and load-tested in the laboratory. The physical characteristics of ...

  8. Simultaneous density-field visualization and PIV of the Richtmyer-Meshkov instability

    NASA Astrophysics Data System (ADS)

    Prestridge, Katherine; Rightley, Paul; Benjamin, Robert; Kurnit, Norman; Boxx, Isaac; Vorobieff, Peter

    1999-11-01

    We describe a highly-detailed experimental characterization of the Richtmyer-Meshkov instability. A vertical curtain of heavy gas (SF_6) flows into the test section of an air-filled, horizontal shock tube, and the instability evolves after the passage of a Mach 1.2 shock past the curtain. The evolution of the curtain is visualized by seeding the SF6 with small (d ≈ 0.5 μm) glycol/water droplets using a modified theatrical fog generator. Because the event lasts only 1 ms and the initial conditions vary from test to test, rapid and high-resolution (both spatial and temporal) data acquisition is required in order to characterize the initial and dynamic conditions for each experimental event. A customized, frequency-doubled, burst mode Nd:YAG laser and a commercial single-pulse laser are used for the implementation of simultaneous density-field imaging and PIV diagnostics. We have provided data about flow scaling and mixing through image analysis, and PIV data gives us further quantitative physical insight into the evolution of the Richtmyer-Meshkov instability.

  9. Contact thermal shock test of ceramics

    NASA Technical Reports Server (NTRS)

    Rogers, W. P.; Emery, A. F.

    1992-01-01

    A novel quantitative thermal shock test of ceramics is described. The technique employs contact between a metal-cooling rod and hot disk-shaped specimen. In contrast with traditional techniques, the well-defined thermal boundary condition allows for accurate analyses of heat transfer, stress, and fracture. Uniform equibiaxial tensile stresses are induced in the center of the test specimen. Transient specimen temperature and acoustic emission are monitored continuously during the thermal stress cycle. The technique is demonstrated with soda-lime glass specimens. Experimental results are compared with theoretical predictions based on a finite-element method thermal stress analysis combined with a statistical model of fracture. Material strength parameters are determined using concentric ring flexure tests. Good agreement is found between experimental results and theoretical predictions of failure probability as a function of time and initial specimen temperature.

  10. Proof-test-based life prediction of high-toughness pressure vessels

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

    Panontin, T.L.; Hill, M.R.

    1996-02-01

    The paper examines the problems associated with applying proof-test-based life prediction to vessels made of high-toughness metals. Two A106 Gr B pipe specimens containing long, through-wall circumferential flaws were tested. One failed during hydrostatic testing and the other during tension-tension cycling following a hydrostatic test. Quantitative fractography was used to verify experimentally obtained fatigue crack growth rates and a variety of LEFM and EPFM techniques were used to analyze the experimental results. The results show that: plastic collapse analysis provides accurate predictions of screened (initial) crack size when the flow stress is determined experimentally; LEFM analysis underestimates the crack sizemore » screened by the proof test and overpredicts the subsequent fatigue life of the vessel when retardation effects are small (i.e., low proof levels); and, at a high proof-test level (2.4 {times} operating pressure), the large retardation effect on fatigue crack growth due to the overload overwhelmed the deleterious effect on fatigue life from stable tearing during the proof test and alleviated the problem of screening only long cracks due to the high toughness of the metal.« less

  11. Gust wind tunnel study on ballast pick-up by high-speed trains

    NASA Astrophysics Data System (ADS)

    Navarro-Medina, F.; Sanz-Andres, A.; Perez-Grande, I.

    2012-01-01

    This paper describes the experimental setup, procedure, and results obtained, concerning the dynamics of a body lying on a floor, attached to a hinge, and exposed to an unsteady flow, which is a model of the initiation of rotational motion of ballast stones due to the wind generated by the passing of a high-speed train. The idea is to obtain experimental data to support the theoretical model developed in Sanz-Andres and Navarro-Medina (J Wind Eng Ind Aerodyn 98, 772-783, (2010), aimed at analyzing the initial phase of the ballast train-induced-wind erosion (BATIWE) phenomenon. The experimental setup is based on an open circuit, closed test section, low-speed wind tunnel, with a new sinusoidal gust generator mechanism concept, designed and built at the IDR/UPM. The tunnel's main characteristic is the ability to generate a flow with a uniform velocity profile and sinusoidal time fluctuation of the speed. Experimental results and theoretical model predictions are in good agreement.

  12. Active Protection of an MgB2 Test Coil

    PubMed Central

    Park, Dong Keun; Hahn, Seungyong; Bascuñán, Juan; Iwasa, Yukikazu

    2011-01-01

    This paper presents results of a study, experimental and computational, of a detect-and-activate-the-heater protection technique applied to a magnesium diboride (MgB2) test coil operated in semi-persistent mode. The test coil with a winding ID of 25 cm and wound with ~500-m long reacted MgB2 wire was operated at 4.2 K immersed in a bath of liquid helium. In this active technique, upon the initiation of a “hot spot” of a length ~10 cm, induced by a “quench heater,” a “protection heater” (PH) of ~600-cm long planted within the test coil is activated. The normal zone created by the PH is large enough to absorb the test coil’s entire initial stored energy and still keeps the peak temperature within the winding below ~260 K. PMID:22081754

  13. A Multi-Disciplinary University Research Initiative in Hard and Soft Information Fusion: Overview, Research Strategies and Initial Results

    DTIC Science & Technology

    2010-07-01

    Multisource Information Fusion ( CMIF ) along with a team including the Pennsylvania State University (PSU), Iona College (Iona), and Tennessee State...License. 14. ABSTRACT The University at Buffalo (UB) Center for Multisource Information Fusion ( CMIF ) along with a team including the Pennsylvania...of CMIF current research on methods for Test and Evaluation ([7], [8]) involving for example large- factor-space experimental design techniques ([9

  14. Small Crack Growth and Fatigue Life Predictions for High-Strength Aluminium Alloys. Part 1; Experimental and Fracture Mechanics Analysis

    NASA Technical Reports Server (NTRS)

    Wu, X. R.; Newman, J. C.; Zhao, W.; Swain, M. H.; Ding, C. F.; Phillips, E. P.

    1998-01-01

    The small crack effect was investigated in two high-strength aluminium alloys: 7075-T6 bare and LC9cs clad alloy. Both experimental and analytical investigations were conducted to study crack initiation and growth of small cracks. In the experimental program, fatigue tests, small crack and large crack tests A,ere conducted under constant amplitude and Mini-TWIST spectrum loading conditions. A pronounced small crack effect was observed in both materials, especially for the negative stress ratios. For all loading conditions, most of the fatigue life of the SENT specimens was shown to be crack propagation from initial material defects or from the cladding layer. In the analysis program, three-dimensional finite element and A weight function methods were used to determine stress intensity factors and to develop SIF equations for surface and corner cracks at the notch in the SENT specimens. A plastisity-induced crack-closure model was used to correlate small and large crack data, and to make fatigue life predictions, Predicted crack-growth rates and fatigue lives agreed well with experiments. A total fatigue life prediction method for the aluminum alloys was developed and demonstrated using the crack-closure model.

  15. Experimental results of direct containment heating by high-pressure melt ejection into the Surtsey vessel: The DCH-3 and DCH-4 tests

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

    Allen, M.D.; Pilch, M.; Brockmann, J.E.

    Two experiments, DCH-3 and DCH-4, were performed at the Surtsey test facility to investigate phenomena associated with a high-pressure melt ejection (HPME) reactor accident sequence resulting in direct containment heating (DCH). These experiments were performed using the same experimental apparatus with identical initial conditions, except that the Surtsey test vessel contained air in DCH-3 and argon in DCH-4. Inerting the vessel with argon eliminated chemical reactions between metallic debris and oxygen. Thus, a comparison of the pressure response in DCH-3 and DCH-4 gave an indication of the DCH contribution due to metal/oxygen reactions. 44 refs., 110 figs., 43 tabs.

  16. A Viscoelastic Constitutive Model Can Accurately Represent Entire Creep Indentation Tests of Human Patella Cartilage

    PubMed Central

    Pal, Saikat; Lindsey, Derek P.; Besier, Thor F.; Beaupre, Gary S.

    2013-01-01

    Cartilage material properties provide important insights into joint health, and cartilage material models are used in whole-joint finite element models. Although the biphasic model representing experimental creep indentation tests is commonly used to characterize cartilage, cartilage short-term response to loading is generally not characterized using the biphasic model. The purpose of this study was to determine the short-term and equilibrium material properties of human patella cartilage using a viscoelastic model representation of creep indentation tests. We performed 24 experimental creep indentation tests from 14 human patellar specimens ranging in age from 20 to 90 years (median age 61 years). We used a finite element model to reproduce the experimental tests and determined cartilage material properties from viscoelastic and biphasic representations of cartilage. The viscoelastic model consistently provided excellent representation of the short-term and equilibrium creep displacements. We determined initial elastic modulus, equilibrium elastic modulus, and equilibrium Poisson’s ratio using the viscoelastic model. The viscoelastic model can represent the short-term and equilibrium response of cartilage and may easily be implemented in whole-joint finite element models. PMID:23027200

  17. WHEN ONSET MEETS DESISTANCE: COGNITIVE TRANSFORMATION AND ADOLESCENT MARIJUANA EXPERIMENTATION.

    PubMed

    Kreager, Derek A; Ragan, Daniel T; Nguyen, Holly; Staff, Jeremy

    2016-06-01

    Desistance scholars primarily focus on changing social roles, cognitive transformations, and shifting identities to understand the cessation of serious crime and illicit drug use in adulthood. In the current study, we move the spotlight away from adulthood and toward adolescence, the developmental stage when the prevalence of offending and substance use peak and desistance from most of these behaviors begins. Our primary hypothesis is that changes in perceived psychic rewards surrounding initial forays into marijuana use strongly predict adolescents' decisions to cease or persist that behavior. In addition, based on social learning expectations, we hypothesize that peer perceptions and behaviors provide mechanisms for perceptual change. We test these hypotheses using longitudinal data of marijuana use, perceptions, and peer networks from the PROmoting School-community-university Partnerships to Enhance Resilience (PROSPER) study. We estimate hazard models of marijuana initiation and within-person models of perceptual updating for youth from grades 6 to 12 ( n =6,154). We find that changes in marijuana's perceived psychic rewards surrounding initiation differentiated experimenters from persisters. Experimenters had significantly lower updated perceptions of marijuana as a fun behavior compared to persisters and these perceptions dropped after the initiation wave. In contrast, persisters updated their perceptions in upward directions and maintained more positive perceptions over time. Inconsistent with social learning expectations, initiators' updated perceptions of marijuana as a fun activity were not explained by peer-reported behaviors or attitudes.

  18. Effect of Abdominal Loading Location on Liver Motion: Experimental Assessment using Ultrafast Ultrasound Imaging and Simulation with a Human Body Model.

    PubMed

    Le Ruyet, Anicet; Berthet, Fabien; Rongiéras, Frédéric; Beillas, Philippe

    2016-11-01

    A protocol based on ultrafast ultrasound imaging was applied to study the in situ motion of the liver while the abdomen was subjected to compressive loading at 3 m/s by a hemispherical impactor or a seatbelt. The loading was applied to various locations between the lower abdomen and the mid thorax while feature points inside the liver were followed on the ultrasound movie (2000 frames per second). Based on tests performed on five post mortem human surrogates (including four tested in the current study), trends were found between the loading location and feature point trajectory parameters such as the initial angle of motion or the peak displacement in the direction of impact. The impactor tests were then simulated using the GHBMC M50 human body model that was globally scaled to the dimensions of each surrogate. Some of the experimental trends observed could be reproduced in the simulations (e.g. initial angle) while others differed more widely (e.g. final caudal motion). The causes for the discrepancies need to be further investigated. The liver strain energy density predicted by the model was also widely affected by the impact location. Experimental and simulation results both highlight the importance of the liver position with respect to the impactor when studying its response in situ.

  19. Experimental Studies on the Mechanical Behaviour of Rock Joints with Various Openings

    NASA Astrophysics Data System (ADS)

    Li, Y.; Oh, J.; Mitra, R.; Hebblewhite, B.

    2016-03-01

    The mechanical behaviour of rough joints is markedly affected by the degree of joint opening. A systematic experimental study was conducted to investigate the effect of the initial opening on both normal and shear deformations of rock joints. Two types of joints with triangular asperities were produced in the laboratory and subjected to compression tests and direct shear tests with different initial opening values. The results showed that opened rock joints allow much greater normal closure and result in much lower normal stiffness. A semi-logarithmic law incorporating the degree of interlocking is proposed to describe the normal deformation of opened rock joints. The proposed equation agrees well with the experimental results. Additionally, the results of direct shear tests demonstrated that shear strength and dilation are reduced because of reduced involvement of and increased damage to asperities in the process of shearing. The results indicate that constitutive models of rock joints that consider the true asperity contact area can be used to predict shear resistance along opened rock joints. Because rock masses are loosened and rock joints become open after excavation, the model suggested in this study can be incorporated into numerical procedures such as finite-element or discrete-element methods. Use of the model could then increase the accuracy and reliability of stability predictions for rock masses under excavation.

  20. Computational analysis in support of the SSTO flowpath test

    NASA Astrophysics Data System (ADS)

    Duncan, Beverly S.; Trefny, Charles J.

    1994-10-01

    A synergistic approach of combining computational methods and experimental measurements is used in the analysis of a hypersonic inlet. There are four major focal points within this study which examine the boundary layer growth on a compression ramp upstream of the cowl lip of a scramjet inlet. Initially, the boundary layer growth on the NASP Concept Demonstrator Engine (CDE) is examined. The follow-up study determines the optimum diverter height required by the SSTO Flowpath test to best duplicate the CDE results. These flow field computations are then compared to the experimental measurements and the mass average Mach number is determined for this inlet.

  1. Computational Analysis in Support of the SSTO Flowpath Test

    NASA Technical Reports Server (NTRS)

    Duncan, Beverly S.; Trefny, Charles J.

    1994-01-01

    A synergistic approach of combining computational methods and experimental measurements is used in the analysis of a hypersonic inlet. There are four major focal points within this study which examine the boundary layer growth on a compression ramp upstream of the cowl lip of a scramjet inlet. Initially, the boundary layer growth on the NASP Concept Demonstrator Engine (CDE) is examined. The follow-up study determines the optimum diverter height required by the SSTO Flowpath test to best duplicate the CDE results. These flow field computations are then compared to the experimental measurements and the mass average Mach number is determined for this inlet.

  2. EXPERIMENTAL STUDIES OF TRANSIENT EFFECTS IN FAST REACTOR FUELS. SERIES I. UO$sub 2$ IRRADIATIONS

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

    Field, J.H.

    1962-11-15

    An experimental program to evaluate the performance of FCR and EFCR fuel during transient operation is outlined, and the initial series of tests are described in some detail. Test results from five experiments in the TREAT reactor, using 1-in. OD SS-clad UO/sub 2/ fuel specimens, are compared with regard to fuel temperatures, mechanical integrity, and post-irradiation appearance. Incipient fuel pin failure limits for transients are identified with maximum fuel temperatures in the range of 7000 deg F. Multiple transient damage to the cladding is likely for transients above the melting point of the fuel. (auth)

  3. The Marshall Space Flight Center KC-135 zero gravity test program for FY 1982

    NASA Technical Reports Server (NTRS)

    Shurney, R. E. (Editor)

    1983-01-01

    During FY-82, researchers and experimenters from Marshall Space Flight Center (MSFC) conducted 11 separate investigations during 26.3 hr of testing aboard the KC-135 zero-gravity aircraft, based at Ellington Air force Base, Texas. Although this represented fewer hours than initially projected, all experiment and test objectives were met or exceeded. This Technical Memorandum compiles all results achieved by MSFC users during FY-82, a year considered to be highly productive.

  4. Feasibility study of determining axial stress in ferromagnetic bars using reciprocal amplitude of initial differential susceptibility obtained from static magnetization by permanent magnets

    NASA Astrophysics Data System (ADS)

    Deng, Dongge; Wu, Xinjun

    2018-03-01

    An electromagnetic method for determining axial stress in ferromagnetic bars is proposed. In this method, the tested bar is under the static magnetization provided by permanent magnets. The tested bar do not have to be magnetized up to the technical saturation because reciprocal amplitude of initial differential susceptibility (RAIDS) is adopted as the feature parameter. RAIDS is calculated from the radial magnetic flux density Br Lo = 0.5 at the Lift-off Lo = 0.5 mm, radial magnetic flux density Br Lo = 1 at the Lift-off Lo = 1 mm and axial magnetic flux density Bz Lo = 1 at the Lift-off Lo = 1 mm from the surface of the tested bar. Firstly, the theoretical derivation of RAIDS is carried out according to Gauss' law for magnetism, Ampere's Law and the Rayleigh relation in Rayleigh region. Secondly, the experimental system is set up for a 2-meter length and 20 mm diameter steel bar. Thirdly, an experiment is carried out on the steel bar to analyze the relationship between the obtained RAIDS and the axial stress. Experimental results show that the obtained RAIDS decreases almost linearly with the increment of the axial stress inside the steel bar in the initial elastic region. The proposed method has the potential to determine tensile axial stress in the slender cylindrical ferromagnetic bar.

  5. Dynamics of gas-driven eruptions: Experimental simulations using CO2-H2O-polymer system

    NASA Astrophysics Data System (ADS)

    Zhang, Youxue; Sturtevant, B.; Stolper, E. M.

    1997-02-01

    We report exploratory experiments simulating gas-driven eruptions using the CO2-H2O system at room temperature as an analog of natural eruptive systems. The experimental apparatus consists of a test cell and a large tank. Initially, up to 1.0 wt% of CO2 is dissolved in liquid water under a pressure of up to 735 kPa in the test cell. The experiment is initiated by suddenly reducing the pressure of the test cell to a typical tank pressure of 10 kPa. The following are the main results: (1) The style of the process depends on the decompression ratio. There is a threshold decompression ratio above which rapid eruption occurs. (2) During rapid eruption, there is always fragmentation at the liquid-vapor interface. Fragmentation may also occur in the flow interior. (3) Initially, the top of the erupting column ascends at a constant acceleration (instead of constant velocity). (4) Average bubble radius grows as t2/3. (5) When viscosity is 20 times that of pure water or greater, a static foam may be stable after expansion to 97% vesicularity. The experiments provide several insights into natural gas-driven eruptions, including (1) the interplay between bubble growth and ascent of the erupting column must be considered for realistic modeling of bubble growth during gas-driven eruptions, (2) buoyant rise of the bubbly magma is not necessary during an explosive volcanic eruption, and (3) CO2-driven limnic eruptions can be explosive. The violence increases with the initial CO2 content dissolved in water.

  6. Investigation of Natural Circulation Instability and Transients in Passively Safe Small Modular Reactors

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

    Ishii, Mamoru

    The NEUP funded project, NEUP-3496, aims to experimentally investigate two-phase natural circulation flow instability that could occur in Small Modular Reactors (SMRs), especially for natural circulation SMRs. The objective has been achieved by systematically performing tests to study the general natural circulation instability characteristics and the natural circulation behavior under start-up or design basis accident conditions. Experimental data sets highlighting the effect of void reactivity feedback as well as the effect of power ramp-up rate and system pressure have been used to develop a comprehensive stability map. The safety analysis code, RELAP5, has been used to evaluate experimental results andmore » models. Improvements to the constitutive relations for flashing have been made in order to develop a reliable analysis tool. This research has been focusing on two generic SMR designs, i.e. a small modular Simplified Boiling Water Reactor (SBWR) like design and a small integral Pressurized Water Reactor (PWR) like design. A BWR-type natural circulation test facility was firstly built based on the three-level scaling analysis of the Purdue Novel Modular Reactor (NMR) with an electric output of 50 MWe, namely NMR-50, which represents a BWR-type SMR with a significantly reduced reactor pressure vessel (RPV) height. The experimental facility was installed with various equipment to measure thermalhydraulic parameters such as pressure, temperature, mass flow rate and void fraction. Characterization tests were performed before the startup transient tests and quasi-steady tests to determine the loop flow resistance. The control system and data acquisition system were programmed with LabVIEW to realize the realtime control and data storage. The thermal-hydraulic and nuclear coupled startup transients were performed to investigate the flow instabilities at low pressure and low power conditions for NMR-50. Two different power ramps were chosen to study the effect of startup power density on the flow instability. The experimental startup transient results showed the existence of three different flow instability mechanisms, i.e., flashing instability, condensation induced flow instability, and density wave oscillations. In addition, the void-reactivity feedback did not have significant effects on the flow instability during the startup transients for NMR-50. ii Several initial startup procedures with different power ramp rates were experimentally investigated to eliminate the flow instabilities observed from the startup transients. Particularly, the very slow startup transient and pressurized startup transient tests were performed and compared. It was found that the very slow startup transients by applying very small power density can eliminate the flashing oscillations in the single-phase natural circulation and stabilize the flow oscillations in the phase of net vapor generation. The initially pressurized startup procedure was tested to eliminate the flashing instability during the startup transients as well. The pressurized startup procedure included the initial pressurization, heat-up, and venting process. The startup transient tests showed that the pressurized startup procedure could eliminate the flow instability during the transition from single-phase flow to two-phase flow at low pressure conditions. The experimental results indicated that both startup procedures were applicable to the initial startup of NMR. However, the pressurized startup procedures might be preferred due to short operating hours required. In order to have a deeper understanding of natural circulation flow instability, the quasi-steady tests were performed using the test facility installed with preheater and subcooler. The effect of system pressure, core inlet subcooling, core power density, inlet flow resistance coefficient, and void reactivity feedback were investigated in the quasi-steady state tests. The experimental stability boundaries were determined between unstable and stable flow conditions in the dimensionless stability plane of inlet subcooling number and Zuber number. To predict the stability boundary theoretically, linear stability analysis in the frequency domain was performed at four sections of the natural circulation test loop. The flashing phenomena in the chimney section was considered as an axially uniform heat source. And the dimensionless characteristic equation of the pressure drop perturbation was obtained by considering the void fraction effect and outlet flow resistance in the core section. The theoretical flashing boundary showed some discrepancies with previous experimental data from the quasi-steady state tests. In the future, thermal non-equilibrium was recommended to improve the accuracy of flashing instability boundary. As another part of the funded research, flow instabilities of a PWR-type SMR under low pressure and low power conditions were investigated experimentally as well. The NuScale reactor design was selected as the prototype for the PWR-type SMR. In order to experimentally study the natural circulation behavior of NuScale iii reactor during accidental scenarios, detailed scaling analyses are necessary to ensure that the scaled phenomena could be obtained in a laboratory test facility. The three-level scaling method is used as well to obtain the scaling ratios derived from various non-dimensional numbers. The design of the ideally scaled facility (ISF) was initially accomplished based on these scaling ratios. Then the engineering scaled facility (ESF) was designed and constructed based on the ISF by considering engineering limitations including laboratory space, pipe size, and pipe connections etc. PWR-type SMR experiments were performed in this well-scaled test facility to investigate the potential thermal hydraulic flow instability during the blowdown events, which might occur during the loss of coolant accident (LOCA) and loss of heat sink accident (LOHS) of the prototype PWR-type SMR. Two kinds of experiments, normal blowdown event and cold blowdown event, were experimentally investigated and compared with code predictions. The normal blowdown event was experimentally simulated since an initial condition where the pressure was lower than the designed pressure of the experiment facility, while the code prediction of blowdown started from the normal operation condition. Important thermal hydraulic parameters including reactor pressure vessel (RPV) pressure, containment pressure, local void fraction and temperature, pressure drop and natural circulation flow rate were measured and analyzed during the blowdown event. The pressure and water level transients are similar to the experimental results published by NuScale [51], which proves the capability of current loop in simulating the thermal hydraulic transient of real PWR-type SMR. During the 20000s blowdown experiment, water level in the core was always above the active fuel assemble during the experiment and proved the safety of natural circulation cooling and water recycling design of PWR-type SMR. Besides, pressure, temperature, and water level transient can be accurately predicted by RELAP5 code. However, the oscillations of natural circulation flow rate, water level and pressure drops were observed during the blowdown transients. This kind of flow oscillations are related to the water level and the location upper plenum, which is a path for coolant flow from chimney to steam generator and down comer. In order to investigate the transients start from the opening of ADS valve in both experimental and numerical way, the cold blow-down experiment is conducted. For the cold blowdown event, different from setting both reactor iv pressure vessel (RPV) and containment at high temperature and pressure, only RPV was heated close to the highest designed pressure and then open the ADS valve, same process was predicted using RELAP5 code. By doing cold blowdown experiment, the entire transients from the opening of ADS can be investigated by code and benchmarked with experimental data. Similar flow instability observed in the cold blowdown experiment. The comparison between code prediction and experiment data showed that the RELAP5 code can successfully predict the pressure void fraction and temperature transient during the cold blowdown event with limited error, but numerical instability exists in predicting natural circulation flow rate. Besides, the code is lack of capability in predicting the water level related flow instability observed in experiments.« less

  7. An experimental study of compression failure of fibrous laminated composites in the presence of stress gradients

    NASA Technical Reports Server (NTRS)

    Waas, A. M.; Knauss, W. G.; Babcock, C. D., Jr.

    1990-01-01

    Mechanisms of failure in laminates in the presence of a stress raiser were experimentally studied. The damage initiation and propagation throughout the entire load history were examined via real-time holographic interferometry and photomicrography of the hole surface. Multilayered composite flat plates made of T300/BP907 and IM7/8551-7 were tested. It is shown that the failure is initiated as a localized instability in the 0-deg plies at the hole surface approximately at right angles to the loading direction. A series of events is described which culminates in the complete loss of flexural stiffness of each of the delaminated portions, leading to catastrophic failure of the plate.

  8. Film condensation in a horizontal rectangular duct

    NASA Technical Reports Server (NTRS)

    Lu, Qing; Suryanarayana, N. V.

    1993-01-01

    Condensation heat transfer in a horizontal rectangular duct was experimentally and analytically investigated. To prevent the dripping of condensate on the film, the experiment was conducted inside a horizontal rectangular duct with vapor condensing only on the bottom cooled plate of the duct. R-113 and FC-72 (Fluorinert Electronic Fluid developed by the 3M Company) were used as the condensing fluids. The experimental program included measurements of film thickness, local and average heat transfer coefficients, wave length, wave speed, and a study of wave initiation. The measured film thickness was used to obtain the local heat transfer coefficient. The wave initiation was studied both with condensation and with an adiabatic air-liquid flow. The test sections used in both experiments were identical.

  9. A study of roll attractor and wing rock of delta wings at high angles of attack

    NASA Technical Reports Server (NTRS)

    Niranjana, T.; Rao, D. M.; Pamadi, Bandu N.

    1993-01-01

    Wing rock is a high angle of attack dynamic phenomenon of limited cycle motion predominantly in roll. The wing rock is one of the limitations to combat effectiveness of the fighter aircraft. Roll Attractor is the steady state or equilibrium trim angle (phi(sub trim)) attained by the free-to-roll model, held at some angle of attack, and released form rest at a given initial roll (bank) angle (phi(sub O)). Multiple roll attractors are attained at different trim angles depending on initial roll angle. The test facility (Vigyan's low speed wind tunnel) and experimental work is presented here along with mathematical modelling of roll attractor phenomenon and analysis and comparison of predictions with experimental data.

  10. Experimental test of an eco-evolutionary dynamic feedback loop between evolution and population density in the green peach aphid.

    PubMed

    Turcotte, Martin M; Reznick, David N; Daniel Hare, J

    2013-05-01

    An eco-evolutionary feedback loop is defined as the reciprocal impacts of ecology on evolutionary dynamics and evolution on ecological dynamics on contemporary timescales. We experimentally tested for an eco-evolutionary feedback loop in the green peach aphid, Myzus persicae, by manipulating initial densities and evolution. We found strong evidence that initial aphid density alters the rate and direction of evolution, as measured by changes in genotype frequencies through time. We also found that evolution of aphids within only 16 days, or approximately three generations, alters the rate of population growth and predicts density compared to nonevolving controls. The impact of evolution on population dynamics also depended on density. In one evolution treatment, evolution accelerated population growth by up to 10.3% at high initial density or reduced it by up to 6.4% at low initial density. The impact of evolution on population growth was as strong as or stronger than that caused by a threefold change in intraspecific density. We found that, taken together, ecological condition, here intraspecific density, alters evolutionary dynamics, which in turn alter concurrent population growth rate (ecological dynamics) in an eco-evolutionary feedback loop. Our results suggest that ignoring evolution in studies predicting population dynamics might lead us to over- or underestimate population density and that we cannot predict the evolutionary outcome within aphid populations without considering population size.

  11. Experimental Study on the Growth, Coalescence and Wrapping Behaviors of 3D Cross-Embedded Flaws Under Uniaxial Compression

    NASA Astrophysics Data System (ADS)

    Zhou, Xiao-Ping; Zhang, Jian-Zhi; Wong, Louis Ngai Yuen

    2018-05-01

    The crack initiation, growth, wrapping and coalescence of two 3D pre-existing cross-embedded flaws in PMMA specimens under uniaxial compression are investigated. The stress-strain curves of PMMA specimens with 3D cross-embedded flaws are obtained. The tested PMMA specimens exhibit dominant elastic deformation and eventual brittle failure. The experimental results show that four modes of crack initiation and five modes of crack coalescence are observed. The initiations of oblique secondary crack and anti-wing crack in 3D cracking behaviors are first reported as well as the coalescence of anti-wing cracks. Moreover, two types of crack wrapping are found. Substantial wrapping of petal cracks, which includes open and closed modes of wrapping, appears to be the major difference between 2D and 3D cracking behaviors of pre-existing flaws, which are also first reported. Petal crack wraps symmetrically from either the propagated wing cracks or the coalesced wing cracks. Besides, only limited growth of petal cracks is observed, and ultimate failure of specimens is induced by the further growth of the propagated wing crack. The fracture mechanism of the tested PMMA specimens is finally revealed. In addition, the initiation stress and the peak stress versus the geometry of two 3D pre-existing cross-embedded flaws are also investigated in detail.

  12. Upgrade of Irradiation Test Capability of the Experimental Fast Reactor Joyo

    NASA Astrophysics Data System (ADS)

    Sekine, Takashi; Aoyama, Takafumi; Suzuki, Soju; Yamashita, Yoshioki

    2003-06-01

    The JOYO MK-II core was operated from 1983 to 2000 as fast neutron irradiation bed. In order to meet various requirements for irradiation tests for development of FBRs, the JOYO upgrading project named MK-III program was initiated. The irradiation capability in the MK-III core will be about four times larger than that of the MK-II core. Advanced irradiation test subassemblies such as capsule type subassembly and on-line instrumentation rig are planned. As an innovative reactor safety system, the irradiation test of Self-Actuated Shutdown System (SASS) will be conducted. In order to improve the accuracy of neutron fluence, the core management code system was upgraded, and the Monte Carlo code and Helium Accumulation Fluence Monitor (HAFM) were applied. The MK-III core is planned to achieve initial criticality in July 2003.

  13. 75 FR 36467 - Livability Initiative Under Special Experimental Project No. 14

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-25

    ...] Livability Initiative Under Special Experimental Project No. 14 AGENCY: Federal Highway Administration (FHWA...). Under this initiative, the FHWA will utilize Special Experimental Project No. 14 (SEP-14) to permit, on... in order to use Federal-aid highway funds. DATES: This new experimental project is being initiated on...

  14. 75 FR 5951 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-05

    ... similar to a fish trap but has an adjustable entrance and exit. It would be tested under an experimental design developed with input from NMFS' Southeast Fisheries Science Center. The gear initially would be...

  15. Peridynamic Applications for Orthotropic Materials

    DTIC Science & Technology

    2012-09-26

    test and a vibration excitation of a laminated beam. An SEN (single edge notch) test of a 0° laminated plate was simulated by peridynamics and the...computational results matched very well with published experimental results. Fracture initiation and crack path of laminated plates with different fiber...Dwivedi [1] modeled the propagation of single-edge notch (SEN) in 0° laminated plate using cohesizve zone method. Xu [2] and Hu [3] proposed a two

  16. Preliminary Failure Modes and Effects Analysis of the US DCLL Test Blanket Module

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

    Lee C. Cadwallader

    2010-06-01

    This report presents the results of a preliminary failure modes and effects analysis (FMEA) of a small tritium-breeding test blanket module design for the International Thermonuclear Experimental Reactor. The FMEA was quantified with “generic” component failure rate data, and the failure events are binned into postulated initiating event families and frequency categories for safety assessment. An appendix to this report contains repair time data to support an occupational radiation exposure assessment for test blanket module maintenance.

  17. Preliminary Failure Modes and Effects Analysis of the US DCLL Test Blanket Module

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

    Lee C. Cadwallader

    2007-08-01

    This report presents the results of a preliminary failure modes and effects analysis (FMEA) of a small tritium-breeding test blanket module design for the International Thermonuclear Experimental Reactor. The FMEA was quantified with “generic” component failure rate data, and the failure events are binned into postulated initiating event families and frequency categories for safety assessment. An appendix to this report contains repair time data to support an occupational radiation exposure assessment for test blanket module maintenance.

  18. Progressive Failure Studies of Stiffened Panels Subjected to Shear Loading

    NASA Technical Reports Server (NTRS)

    Ambur, Damodar R.; Jaunky, Navin; Hilburger, Mark W.; Bushnell, Dennis M. (Technical Monitor)

    2002-01-01

    Experimental and analytical results are presented for progressive failure of stiffened composite panels with and without a notch and subjected to in plane shear loading well into their postbuckling regime. Initial geometric imperfections are included in the finite element models. Ply damage modes such as matrix cracking, fiber-matrix shear, and fiber failure are modeled by degrading the material properties. Experimental results from the test include strain field data from video image correlation in three dimensions in addition to other strain and displacement measurements. Results from nonlinear finite element analyses are compared with experimental data. Good agreement between experimental data and numerical results are observed for the stitched stiffened composite panels studied.

  19. Development of a CFD Code for Analysis of Fluid Dynamic Forces in Seals

    NASA Technical Reports Server (NTRS)

    Athavale, Mahesh M.; Przekwas, Andrzej J.; Singhal, Ashok K.

    1991-01-01

    The aim is to develop a 3-D computational fluid dynamics (CFD) code for the analysis of fluid flow in cylindrical seals and evaluation of the dynamic forces on the seals. This code is expected to serve as a scientific tool for detailed flow analysis as well as a check for the accuracy of the 2D industrial codes. The features necessary in the CFD code are outlined. The initial focus was to develop or modify and implement new techniques and physical models. These include collocated grid formulation, rotating coordinate frames and moving grid formulation. Other advanced numerical techniques include higher order spatial and temporal differencing and an efficient linear equation solver. These techniques were implemented in a 2D flow solver for initial testing. Several benchmark test cases were computed using the 2D code, and the results of these were compared to analytical solutions or experimental data to check the accuracy. Tests presented here include planar wedge flow, flow due to an enclosed rotor, and flow in a 2D seal with a whirling rotor. Comparisons between numerical and experimental results for an annular seal and a 7-cavity labyrinth seal are also included.

  20. Analytical and experimental vibration studies of a 1/8-scale shuttle orbiter

    NASA Technical Reports Server (NTRS)

    Pinson, L. D.

    1975-01-01

    Natural frequencies and mode shapes for four symmetric vibration modes and four antisymmetric modes are compared with predictions based on NASTRAN finite-element analyses. Initial predictions gave poor agreement with test data; an extensive investigation revealed that the major factors influencing agreement were out-of-plane imperfections in fuselage panels and a soft fin-fuselage connection. Computations with a more refined analysis indicated satisfactory frequency predictions for all modes studied, within 11 percent of experimental values.

  1. Fatigue In Continuous-Fiber/Metal-Matrix Composites

    NASA Technical Reports Server (NTRS)

    Johnson, William S.

    1992-01-01

    Report describes experimental approaches to quantification of fatigue damage in metal-matrix composites (MMC's). Discusses number of examples of development of damage and failure along with associated analytical models of behavior of MMC. Objectives of report are twofold. First, present experimental procedures and techniques for conducting meaningful fatigue tests to detect and quantify fatigue damage in MMC's. Second, present examples of how fatigue damage initiated and grows in various MMC's. Report furnishes some insight into what type of fatigue damage occurs and how damage quantified.

  2. ANTIPLAQUE AND ANTIGINGIVITIS EFFECT OF LIPPIA SIDOIDES. A DOUBLE-BLIND CLINICAL STUDY IN HUMANS

    PubMed Central

    Rodrigues, Ítalo Sarto Carvalho; Tavares, Vinícius Nascimento; Pereira, Sérgio Luís da Silva; da Costa, Flávio Nogueira

    2009-01-01

    Objectives: The antiplaque and antigingivitis effect of Lippia Sidoides (LS) was evaluated in this in vivo investigation. Material and Methods: Twenty-three subjects participated in a cross-over, double-blind clinical study, using 21-day partial-mouth experimental model of gingivitis. A toothshield was constructed for each volunteer, avoiding the brushing of the 4 experimental posterior teeth in the lower left quadrant. The subjects were randomly assigned initially to use either the placebo gel (control group) or the test gel, containing 10% LS (test group). Results: The clinical results showed statistically significant differences for plaque index (PLI) (p<0.01) between days 0 and 21 in both groups, however only the control group showed statistically significant difference (p<0.01) for the bleeding (IB) and gingival (GI) index within the experimental period of 21 days. On day 21, the test group presented significantly better results than the control group with regard to the GI (p<0.05). Conclusions: The test gel containing 10% LS was effective in the control of gingivitis. PMID:19936516

  3. Strain-Life Assessment of Grainex Mar-M 247 for NASA's Turbine Seal Test Facility

    NASA Technical Reports Server (NTRS)

    Delgado, Irebert R.; Halford, Gary R.; Steinetz, Bruce M.; Rimnac, Clare M.

    2004-01-01

    NASA s Turbine Seal Test Facility is used to test air-to-air seals for use primarily in advanced jet engine applications. Combinations of high temperature, high speed, and high pressure limit the disk life, due to the concern of crack initiation in the bolt holes of the Grainex Mar-M 247 disk. The primary purpose of this current work is to determine an inspection interval to ensure safe operation. The current work presents high temperature fatigue strain-life data for test specimens cut from an actual Grainex Mar-M 247 disk. Several different strain-life models were compared to the experimental data including the Manson-Hirschberg Method of Universal Slopes, the Halford-Nachtigall Mean Stress Method, and the Modified Morrow Method. The Halford-Nachtigall Method resulted in only an 18 percent difference between predicted and experimental results. Using the experimental data at a 99.95 percent prediction level and the presence of 6 bolt holes it was found that the disk should be inspected after 665 cycles based on a total strain of 0.5 percent at 649 C.

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

    Nabeel A. Riza

    The goals of the first six months of this project were to begin laying the foundations for both the SiC front-end optical chip fabrication techniques for high pressure gas species sensing as well as the design, assembly, and test of a portable high pressure high temperature calibration test cell chamber for introducing gas species. This calibration cell will be used in the remaining months for proposed first stage high pressure high temperature gas species sensor experimentation and data processing. All these goals have been achieved and are described in detail in the report. Both design process and diagrams for themore » mechanical elements as well as the optical systems are provided. Photographs of the fabricated calibration test chamber cell, the optical sensor setup with the calibration cell, the SiC sample chip holder, and relevant signal processing mathematics are provided. Initial experimental data from both the optical sensor and fabricated test gas species SiC chips is provided. The design and experimentation results are summarized to give positive conclusions on the proposed novel high temperature high pressure gas species detection optical sensor technology.« less

  5. GD SDR Automatic Gain Control Characterization Testing

    NASA Technical Reports Server (NTRS)

    Nappier, Jennifer M.; Briones, Janette C.

    2013-01-01

    The General Dynamics (GD) S-Band software defined radio (SDR) in the Space Communications and Navigation (SCAN) Testbed on the International Space Station (ISS) will provide experimenters an opportunity to develop and demonstrate experimental waveforms in space. The GD SDR platform and initial waveform were characterized on the ground before launch and the data will be compared to the data that will be collected during on-orbit operations. A desired function of the SDR is to estimate the received signal to noise ratio (SNR), which would enable experimenters to better determine on-orbit link conditions. The GD SDR does not have an SNR estimator, but it does have an analog and a digital automatic gain control (AGC). The AGCs can be used to estimate the SDR input power which can be converted into a SNR. Tests were conducted to characterize the AGC response to changes in SDR input power and temperature. This purpose of this paper is to describe the tests that were conducted, discuss the results showi ng how the AGCs relate to the SDR input power, and provide recommendations for AGC testing and characterization.

  6. GD SDR Automatic Gain Control Characterization Testing

    NASA Technical Reports Server (NTRS)

    Nappier, Jennifer M.; Briones, Janette C.

    2013-01-01

    The General Dynamics (GD) S-Band software defined radio (SDR) in the Space Communications and Navigation (SCAN) Testbed on the International Space Station (ISS) will provide experimenters an opportunity to develop and demonstrate experimental waveforms in space. The GD SDR platform and initial waveform were characterized on the ground before launch and the data will be compared to the data that will be collected during on-orbit operations. A desired function of the SDR is to estimate the received signal to noise ratio (SNR), which would enable experimenters to better determine on-orbit link conditions. The GD SDR does not have an SNR estimator, but it does have an analog and a digital automatic gain control (AGC). The AGCs can be used to estimate the SDR input power which can be converted into a SNR. Tests were conducted to characterize the AGC response to changes in SDR input power and temperature. This purpose of this paper is to describe the tests that were conducted, discuss the results showing how the AGCs relate to the SDR input power, and provide recommendations for AGC testing and characterization.

  7. The impact of football training on motor development in male children.

    PubMed

    Erceg, Marko; Zagorac, Nebojsa; Katić, Ratko

    2008-03-01

    The aim of the study was to determine the effect of football school program and physical education curriculum on changes in the motor abilities of 7- and 8-year-old boys. The study included a sample of 180 boys divided into group 1 (7-year-old boys), subdivided to experimental (n = 40) and control (n = 50) groups, and group 2 (8-year-old boys), subdivided to experimental (n = 40) and control (n = 50) groups. Experimental groups included children attending three training units of football training over a 9-month period, in addition to the conventional physical education curriculum. Control groups included children attending only conventional physical education curriculum. All study subjects underwent testing with a battery of 12 motor tests at the beginning and at the end of the study. Results obtained by discriminative canonic analysis showed no statistically significant between-group difference in motor abilities at the beginning of the study. However, significant differences in favor of experimental groups were recorded at the end of the study. Favorable changes in all motor variables were observed in both experimental and control groups of children from the initial through the final state. These changes were more pronounced in experimental groups. Analysis of variance for difference variables (final to initial measurement) indicated programmed education in the form of football training in addition to regular physical education curriculum to predominantly influence the development of aerobic endurance, agility, speed and flexibility in 7-year-old boys, and of explosive strength, aerobic endurance, flexibility and speed in 8-year-old boys. In the latter, football training led to the formation of a motor complex integrating explosiveness, speed, coordination, endurance and flexibility as a general motor factor determining future quality development in football.

  8. Coupling lateral bending and shearing mechanisms to define knee injury criteria for pedestrian safety.

    PubMed

    Mo, Fuhao; Masson, Catherine; Cesari, Dominique; Arnoux, Pierre Jean

    2013-01-01

    In car-pedestrian accidents, lateral bending and shearing kinematics have been identified as principal injury mechanisms causing permanent disabilities and impairments to the knee joint. Regarding the combined lateral bending and shearing contributions of knee joint kinematics, developing a coupled knee injury criterion is necessary for improving vehicle countermeasures to mitigate pedestrian knee injuries. The advantages of both experimental tests and finite element (FE) simulations were combined to determine the reliable injury tolerances of the knee joint. First, 7 isolated lower limb tests from postmortem human subjects (PMHS) were reported, with dynamic loading at a velocity of 20 km/h. With the intention of replicating relevant injury mechanisms of vehicle-pedestrian impacts, the experimental tests were categorized into 3 groups by the impact locations on the tibia: the distal end to prioritize pure bending, the middle diaphysis to have combined bending and shearing effects, and the proximal end to acquire pure shearing. Then, the corresponding FE model was employed to provide an additional way to determine exact injury occurrences and develop a robust knee injury criterion by the variation in both the lateral bending and shearing contributions through a sensitivity analysis of impact locations. Considering the experimental test results and the subsequent sensitivity analysis of FE simulations, both the tolerances and patterns of knee joint injuries were determined to be influenced by impact locations due to various combined contributions of lateral bending and shearing. Both medial collateral ligament and cruciate ligament failures were noted as the onsets of knee injuries, namely, initial injuries. Finally, a new injury criterion categorized by initial injury patterns of knee joint was proposed by coupling lateral bending and shearing levels. The developed injury criterion correlated the combined joint kinematics to initial knee injuries based on subsegment tests and FE simulations conducted with a biofidelic lower limb model. This provides a valuable way of predicting the risk of knee injury associated with vehicle-pedestrian crashes and thereby represents a further step to promote the design of vehicle countermeasures for pedestrian safety.

  9. 78 FR 73518 - Notice Inviting Suggestions for New Experiments for the Experimental Sites Initiative; Federal...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-06

    ... ideas for new institutionally based experiments designed to test alternative ways of administering the... Secretary will design experiments and corresponding evaluation plans. The Secretary will subsequently... requirements. Many of these requirements are also designed to provide protections and safeguards to students...

  10. Synthesis and testing of ZnO nanoparticles for photo-initiation: experimental observation of two different non-migration initiators for bulk polymerization.

    PubMed

    Schmitt, M

    2015-06-07

    The migration and transport of polymerization initiators are problematic for commercially used polymerization procedures. For example, UV printing of packaging generates products with potentially harmful components that come in contact with food. Enlarging the size of the initiator is the only way to prevent contamination, e.g., by gas phase transport. In this manuscript, the synthesis and advanced and full analyses of novel nanoparticle-based types of non-migration, fragmenting and non-fragmenting photo-initiators will be presented in detail. This study introduces non-fragmenting/"Norrish type II" and fragmenting/"Norrish type I" ZnO nanoparticle-based initiators and compares them with two commercial products, a "Norrish type I" initiator and a "Norrish type II" initiator. Therefore, inter alia, the recently developed analysis involves examining the solidification by UV-vis and the double bond content by Raman. Irradiation is performed using absolute and spectrally calibrated xenon flash lights. A novel procedure for absolute and spectral calibration of such light sources is also presented. The non-optimized "Norrish type II" particle-based initiator is already many times faster than benzophenone, which is a molecular initiator of the same non-fragmenting type. This experimentally observed difference in reactive particle-based systems without co-initiators is unexpected. Co-initiators are normally an additional molecular species, which leads to migration problems. The discovery of significant initiation potential resulting in a very well-dispersed organic-inorganic hybrid material suggests a new field of research opportunities at the interface of physical chemistry, polymer chemistry and engineering science, with enormous value for human health.

  11. Initial Fire Suppression Reactions of Halons Phase 1. Development of Experimental Approach

    DTIC Science & Technology

    1990-09-01

    Engineering News, pp. 22-46, August 31, 1987. Mitani, T., " Flame Retardant Effects of CF 3Br and NaHCO 3 Combustion and Flame , Vol. 50, pp. 177-188, 1983...occurring when halons enter flame fronts are unclear. It is these initial reactions, however, that determine differences in halon performance, the effect of...LABORATORY FLAMES Over the past four decades, numerous tests have been performed in an effort to characterize the relative effectiveness of candidate

  12. Lead paint removal with high-intensity light pulses.

    PubMed

    Grapperhaus, Michael J; Schaefer, Raymond B

    2006-12-15

    This paper presents the results of an initial investigation into using high-intensity incoherent light pulses to strip paint. Measurements of light pulse characteristics, the reflectivity of different paints and initial experiments on the threshold for paint removal, and paint removal are presented, along with an approximate model consistent with experimental results. Paint removal tests include lead paint, the reduction of lead levels to below levels required for lead abatement, as well as air and light emissions measurements that are within regulatory guidelines.

  13. Very Low Thrust Gaseous Oxygen-hydrogen Rocket Engine Ignition Technology

    NASA Technical Reports Server (NTRS)

    Bjorklund, Roy A.

    1983-01-01

    An experimental program was performed to determine the minimum energy per spark for reliable and repeatable ignition of gaseous oxygen (GO2) and gaseous hydrogen (GH2) in very low thrust 0.44 to 2.22-N (0.10 to 0.50-lb sub f) rocket engines or spacecraft and satellite attitude control systems (ACS) application. Initially, the testing was conducted at ambient conditions, with the results subsequently verified under vacuum conditions. An experimental breadboard electrical exciter that delivered 0.2 to 0.3 mj per spark was developed and demonstrated by repeated ignitions of a 2.22-N (0.50-lb sub f) thruster in a vacuum chamber with test durations up to 30 min.

  14. Using Behavioral Economic Theory to Increase Use of Effective Contraceptives among Opioid-maintained Women at Risk of Unintended Pregnancy

    PubMed Central

    Heil, Sarah H.; Hand, Dennis J.; Sigmon, Stacey C.; Badger, Gary J.; Meyer, Marjorie C.; Higgins, Stephen T.

    2016-01-01

    Objective An unsettling aspect of the US opioid epidemic is the high rate of in utero exposure, especially since most of these pregnancies are unintended, due in part to low rates of effective contraceptive use among opioid-using women. This study tested an intervention informed by behavioral economic theory and aimed at promoting effective contraceptive use among opioid-maintained women at risk of unintended pregnancy in the Burlington, VT area between 2011–2013. Methods Thirty-one women were assigned (initial 5 consecutively, subsequent 26 randomly) to either usual care or an experimental intervention. Participants in usual care received condoms, a dose of emergency contraception, and referral to local providers. Participants in the experimental condition received usual care plus the World Health Organization’s contraception initiation protocol, including free prescription contraceptives, and financial incentives for attending 13 follow-up visits over 6 months to help manage side effects and other issues. Results Significantly more women in the experimental vs. usual care control conditions initiated prescription contraceptive use (100% vs. 29%) and reported prescription contraceptive use at 1-month (63% vs. 13%), 3-month (88% vs. 20%), and 6-month (94% vs. 13%) assessments. None of the experimental condition participants became pregnant during the 6-month protocol vs. three women (20%) in the control condition. Conclusions These results provide the first experimental evidence supporting the efficacy of an intervention for increasing prescription contraceptive use among opioid-maintained women at risk of unintended pregnancy. PMID:27346756

  15. Experimental Evaluation of Fatigue Crack Initiation from Corroded Hemispherical Notches in Aerospace Structural Materials

    NASA Technical Reports Server (NTRS)

    Garcia, Daniel B.; Forman, Royce; Shindo, David

    2010-01-01

    A test program was developed and executed to evaluate the influence of corroded hemispherical notches on the fatigue crack initiation and propagation in aluminum 7075-T7351, 4340 steel, and D6AC steel. Surface enhancements such as shot peening and laser shock peening were also incorporated as part of the test effort with the intent of improving fatigue performance. In addition to the testing, fracture mechanics and endurance limit based analysis methods were evaluated to characterize the results with the objective of challenging typical assumptions used in modeling fatigue cracks from corrosion pits. The results specifically demonstrate that the aluminum and steel alloys behave differently with respect to fatigue crack initiation from hemispherical corrosion pits. The aluminum test results were bounded by the fracture mechanics and endurance limit models while exhibiting a general insensitivity to the residual stress field generated by shot peening. The steel specimens were better characterized by the endurance limit fatigue properties and did exhibit sensitivities to residual stresses from the shot peening and laser shock peening

  16. Histomorphometric study of the periodontal ligament in the initial period of orthodontic movement in Wistar rats with induced allergic asthma.

    PubMed

    Machado, Cristiane Correia Pereira; Nojima, Matilde da Cunha Gonçalves; Rodrigues e Silva, Patrícia Machado; Mandarim-de-Lacerda, Carlos Alberto

    2012-09-01

    Asthma is a common systemic disease occurring in infancy and adolescence, time periods that could encompass orthodontic treatment. Asthma is an inflammatory disease; therefore, it might interfere with orthodontic tooth movement. The purpose of the study was to analyze the histomorphologic aspects of the periodontal ligament of asthmatic Wistar rats in the initial period of orthodontic movement. Thirty-two Wistar rats were divided into 4 groups: 2 control groups consisting of rats without induced allergic asthma, and 2 experimental groups consisting of rats with induced allergic asthma. The animals of the first control and experimental groups did not receive orthodontic forces, whereas those in the second control and experimental groups were subjected to mesial movement of the maxillary left first molar for 3 days. The samples were prepared for histomorphometric analysis of the periodontal ligament. The area of the periodontal ligament was calculated as a function of root length in the cervical and apical regions of the distal face of the maxillary first molar mesial root. The Student t test and the Welch correlation test were applied to the data obtained. There was a statistically significant difference (P <0.05) between the control and experimental groups. An enhanced response to orthodontic force was observed in the asthmatic animals: the periodontal ligament was more compressed at the pressure area and more stretched in the traction area. Our findings indicate that experimental allergic asthma seems to exacerbate orthodontic movement in rats. Copyright © 2012 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  17. Assessment of MARMOT Grain Growth Model

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

    Fromm, B.; Zhang, Y.; Schwen, D.

    2015-12-01

    This report assesses the MARMOT grain growth model by comparing modeling predictions with experimental results from thermal annealing. The purpose here is threefold: (1) to demonstrate the validation approach of using thermal annealing experiments with non-destructive characterization, (2) to test the reconstruction capability and computation efficiency in MOOSE, and (3) to validate the grain growth model and the associated parameters that are implemented in MARMOT for UO 2. To assure a rigorous comparison, the 2D and 3D initial experimental microstructures of UO 2 samples were characterized using non-destructive Synchrotron x-ray. The same samples were then annealed at 2273K for grainmore » growth, and their initial microstructures were used as initial conditions for simulated annealing at the same temperature using MARMOT. After annealing, the final experimental microstructures were characterized again to compare with the results from simulations. So far, comparison between modeling and experiments has been done for 2D microstructures, and 3D comparison is underway. The preliminary results demonstrated the usefulness of the non-destructive characterization method for MARMOT grain growth model validation. A detailed analysis of the 3D microstructures is in progress to fully validate the current model in MARMOT.« less

  18. The benchmark aeroelastic models program: Description and highlights of initial results

    NASA Technical Reports Server (NTRS)

    Bennett, Robert M.; Eckstrom, Clinton V.; Rivera, Jose A., Jr.; Dansberry, Bryan E.; Farmer, Moses G.; Durham, Michael H.

    1991-01-01

    An experimental effort was implemented in aeroelasticity called the Benchmark Models Program. The primary purpose of this program is to provide the necessary data to evaluate computational fluid dynamic codes for aeroelastic analysis. It also focuses on increasing the understanding of the physics of unsteady flows and providing data for empirical design. An overview is given of this program and some results obtained in the initial tests are highlighted. The tests that were completed include measurement of unsteady pressures during flutter of rigid wing with a NACA 0012 airfoil section and dynamic response measurements of a flexible rectangular wing with a thick circular arc airfoil undergoing shock boundary layer oscillations.

  19. Active learning of geometrical optics in high school: the ALOP approach

    NASA Astrophysics Data System (ADS)

    Alborch, Alejandra; Pandiella, Susana; Benegas, Julio

    2017-09-01

    A group comparison experiment of two high school classes with pre and post instruction testing has been carried out to study the suitability and advantages of using the active learning of optics and photonics (ALOP) curricula in high schools of developing countries. Two parallel, mixed gender, 12th grade classes of a high school run by the local university were chosen. One course was randomly selected to follow the experimental instruction, based on teacher and student activities contained in the ALOP Manual. The other course followed the traditional, teacher-centered, instruction previously practiced. Conceptual knowledge of the characteristics of image formation by plane mirrors and single convergent and divergent lenses was measured by applying, in both courses, the multiple-choice test, light and optics conceptual evaluation (LOCE). Measurement before instruction showed that initial knowledge was almost null, and therefore equivalent, in both courses. After instruction testing showed that the conceptual knowledge of students following the ALOP curricula more than doubled that achieved by students in the control course, a situation maintained throughout the six conceptual dimensions tested by the 34 questions of the LOCE test used in this experiment. Using a 60% performance level on the LOCE test as the threshold of satisfactory performance, most (about 90%) of the experimental group achieved this level—independent of initial knowledge, while no student following traditional instruction reached this level of understanding. Some considerations and recommendations for prospective users are also included.

  20. Large area sheet task: Advanced dendritic web growth development

    NASA Technical Reports Server (NTRS)

    Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.; Hopkins, R. H.; Meier, D.; Schruben, J.

    1981-01-01

    The growth of silicon dendritic web for photovoltaic applications was investigated. The application of a thermal model for calculating buckling stresses as a function of temperature profile in the web is discussed. Lid and shield concepts were evaluated to provide the data base for enhancing growth velocity. An experimental web growth machine which embodies in one unit the mechanical and electronic features developed in previous work was developed. In addition, evaluation of a melt level control system was begun, along with preliminary tests of an elongated crucible design. The economic analysis was also updated to incorporate some minor cost changes. The initial applications of the thermal model to a specific configuration gave results consistent with experimental observation in terms of the initiation of buckling vs. width for a given crystal thickness.

  1. Information model of trainee characteristics with definition of stochastic behavior of dynamic system

    NASA Astrophysics Data System (ADS)

    Sumin, V. I.; Smolentseva, T. E.; Belokurov, S. V.; Lankin, O. V.

    2018-03-01

    In the work the process of formation of trainee characteristics with their subsequent change is analyzed and analyzed. Characteristics of trainees were obtained as a result of testing for each section of information on the chosen discipline. The results obtained during testing were input to the dynamic system. The area of control actions consisting of elements of the dynamic system is formed. The limit of deterministic predictability of element trajectories in dynamical systems based on local or global attractors is revealed. The dimension of the phase space of the dynamic system is determined, which allows estimating the parameters of the initial system. On the basis of time series of observations, it is possible to determine the predictability interval of all parameters, which make it possible to determine the behavior of the system discretely in time. Then the measure of predictability will be the sum of Lyapunov’s positive indicators, which are a quantitative measure for all elements of the system. The components for the formation of an algorithm allowing to determine the correlation dimension of the attractor for known initial experimental values of the variables are revealed. The generated algorithm makes it possible to carry out an experimental study of the dynamics of changes in the trainee’s parameters with initial uncertainty.

  2. Two-Level factorial screening of new plasmid/strain combinations for prodution of recombinant-DNA products.

    PubMed

    Emborg, C; Jepsen, P K; Biedermann, K

    1989-05-01

    This article treats the basic problem of selection of experimental conditions for microbiological experiments for evaluation of newly isolated bacterial strains, mutants, or plasmid/strain combinations. For this purpose shake flask experiments in a 2(10-4)confounded factorial design at resolution IV with four blocks of 16 flasks were used. The design was used for testing of two new strain/plasmid combinations (E. coli MT 102/403-SD2 and W 3110/403-SD2) i.e., both strains with the same plasmid 403-SD2. Both strains were integrated in the design, so both strains were tested with nine factors (temperature, aeration, glucose, initial pH, pH regulation, reduced aeration, chloramphenicol, acetate, and glycerol). With both strains the interaction between initial pH and reduced aeration had a significant influence on the yield of the recombinant-DNA product nuclease. There was more than a factor of 10 between lowest and highest yield of product. In this interactive system the strains reacted differently. MT 102/403-SD2 had highest yields at high initial pH (8.4) and no reduction in aeration, whereas W 3110/403-SD2 had highest yields of nuclease at low initial pH (7.4) and reduced aeration (rubber stopper inserted after cultivation for 12 h). These data (and previous work) clearly demonstrate that it is impossible to suggest a simple set of experimental conditions for testing of new plasmid/strain combinations. It is clear that the exclusive application of a standardized growth technique e.g., LB-medium at 37 degrees C at an unspecified and uncontrolled aeration level, may lead to wrong conclusions on properties and potentials of now plasmid/strain combinations and may lead to rejection of useful strains or plasmids.

  3. Investigating compression failure mechanisms in composite laminates with a transparent fiberglass-epoxy birefringent materials

    NASA Technical Reports Server (NTRS)

    Shuart, M. J.; Williams, J. G.

    1984-01-01

    The response and failure of a + or - 45s class laminate was studied by transparent fiberglass epoxy composite birefringent material. The birefringency property allows the laminate stress distribution to be observed during the test and also after the test if permanent residual stresses occur. The location of initial laminate failure and of the subsequent failure propagation are observed through its transparency characteristics. Experimental results are presented.

  4. The Shock and Vibration Bulletin. Part 1. Welcome, Keynote Address, Invited Papers, Pyrotechnic Shock, and Shock Testing and Analysis

    DTIC Science & Technology

    1983-05-01

    DESIGN PROCEDURE M. S. IIAndal, University of Vermont, Burlington, VT Machinery Dynamics ANALYTICAL AND EXPERIMENTAL INVESTIGATION OF ROTATING BLADE... methodology to accurately predict rotor vibratory loads and has recently been initiated for detail design and bench test- coupled rotor/airframe vibrations... design methodology , a trating on the basic disciplines of aerodynamics and struc. coupled rotor/airframe vibration analysis has been developed. tural

  5. Effect of mouthrinses with different active agents in the prevention of initial dental erosion.

    PubMed

    de Oliveira, Tatiane Alexandre; Scaramucci, Tais; Nogueira, Fernando Neves; Simões, Alyne; Sobral, Maria Angela Pita

    2015-01-01

    Hydrochloric acid (HCl) from the gastric juice is the only source of intrinsic acid, which can reach the oral cavity in cases of gastroesophageal reflux or chronic vomiting, enhancing the risk of dental erosion. Compare the effects of mouthrinses with different active agents in the prevention of initial dental erosion caused by HCl. Casein (CAS at 0.2%), sodium hexametaphosphate (HMP at 0.02%), titanium tetrafluoride (TiF4 at 0.34%), and stannous fluoride (SnF2 at 0.87%) were individually added to an experimental mouthrinse. The mouthrinse without additives was used as the negative control (C) and a commercially available mouthrinse for erosion (ELM-Elmex®) as the reference product. Enamel specimens were exposed to human saliva and randomly assigned to 6 experimental groups (n = 8). Specimens were submitted to erosion in HCl for 10 s, followed by to the experimental mouthrinses for 30 s, and artificial saliva for 60 min. This cycle was repeated 3 times. The total amounts of calcium and phosphorus released by the specimens in the 2nd and 3rd erosive challenges were evaluated by atomic emission spectrometry. Statistical analysis used Shapiro-Wilks and Hartley tests, followed by one-way ANOVA and Tukey tests. When compared with C, ELM and HMP presented significantly less calcium in solution, with no difference between them. All the groups showed similar and significantly less phosphorus than C, except CAS. HMP was the only agent that could match the protection against initial erosion of the commercially available mouthrinse in both analyses.

  6. Experimental Investigation of Shock Initiation in Mixtures of Manganese and Sulfur

    NASA Astrophysics Data System (ADS)

    Jetté, F. X.; Goroshin, S.; Higgins, A. J.

    2009-12-01

    Equimolar mixtures of manganese powder and sulfur at different starting densities were tested in two different types of steel recovery capsules in order to study the shock initiation phenomenon in Self-Propagating High-Temperature Synthesis (SHS) mixtures. Two different sizes of Mn particles were used for these experiments, <10 μm and -325 mesh (<44 μm). This mixture was selected due to the large exothermic heat release of the manganese-sulfur reaction (214 kJ/mol), which causes the reaction to be self-sustaining once initiated. The test samples were placed in planar recovery capsules and a strong shock was delivered via the detonation of a charge of amine-sensitized nitromethane. Various shock strengths were achieved by placing different thicknesses of PMMA attenuator discs between the explosive charge and the capsule. The results confirmed that shock-induced reactions can be produced in highly non-porous mixtures. It was also found that shock interactions with the side walls of the recovery capsule can play a significant role in the initiation.

  7. Research on assessment of bolted joint state using elastic wave propagation

    NASA Astrophysics Data System (ADS)

    Kędra, R.; Rucka, M.

    2015-07-01

    The work contains results of experimental investigation of elastic wave propagation in a bolted single-lap joint. Tests were carried out for the excitation perpendicular to the connection plane. In experimental studies, PZT transducers were used for both excitation and registration of ultrasonic waves. The analyses took into account varying contact conditions between the elements of the connection depending on the value of the prestressing force. The influence of loosening/tightening of bolts on the energy dissipation was analysed. The experimental results proved the influence of bolt torque on quantitative characteristics of the signals. To improve the diagnostic possibilities only the initial parts of signals were analysed.

  8. Test Methodology Development for Experimental Structural Assessment of ASC Planar Spring Material for Long-Term Durability

    NASA Technical Reports Server (NTRS)

    Yun, Gunjin; Abdullah, A. B. M.; Binienda, Wieslaw; Krause, David L.; Kalluri, Sreeramesh

    2014-01-01

    A vibration-based testing methodology has been developed that will assess fatigue behavior of the metallic material of construction for the Advanced Stirling Convertor displacer (planar) spring component. To minimize the testing duration, the test setup is designed for base-excitation of a multiplespecimen arrangement, driven in a high-frequency resonant mode; this allows completion of fatigue testing in an accelerated period. A high performance electro-dynamic exciter (shaker) is used to generate harmonic oscillation of cantilever beam specimens, which are clasped on the shaker armature with specially-designed clamp fixtures. The shaker operates in closed-loop control with dynamic specimen response feedback provided by a scanning laser vibrometer. A test coordinator function synchronizes the shaker controller and the laser vibrometer to complete the closed-loop scheme. The test coordinator also monitors structural health of the test specimens throughout the test period, recognizing any change in specimen dynamic behavior. As this may be due to fatigue crack initiation, the test coordinator terminates test progression and then acquires test data in an orderly manner. Design of the specimen and fixture geometry was completed by finite element analysis such that peak stress does not occur at the clamping fixture attachment points. Experimental stress evaluation was conducted to verify the specimen stress predictions. A successful application of the experimental methodology was demonstrated by validation tests with carbon steel specimens subjected to fully-reversed bending stress; high-cycle fatigue failures were induced in such specimens using higher-than-prototypical stresses

  9. Scaling and design analyses of a scaled-down, high-temperature test facility for experimental investigation of the initial stages of a VHTR air-ingress accident

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

    Arcilesi, David J.; Ham, Tae Kyu; Kim, In Hun

    2015-07-01

    A critical event in the safety analysis of the very high-temperature gas-cooled reactor (VHTR) is an air-ingress accident. This accident is initiated, in its worst case scenario, by a double-ended guillotine break of the coaxial cross vessel, which leads to a rapid reactor vessel depressurization. In a VHTR, the reactor vessel is located within a reactor cavity that is filled with air during normal operating conditions. Following the vessel depressurization, the dominant mode of ingress of an air–helium mixture into the reactor vessel will either be molecular diffusion or density-driven stratified flow. The mode of ingress is hypothesized to dependmore » largely on the break conditions of the cross vessel. Since the time scales of these two ingress phenomena differ by orders of magnitude, it is imperative to understand under which conditions each of these mechanisms will dominate in the air ingress process. Computer models have been developed to analyze this type of accident scenario. There are, however, limited experimental data available to understand the phenomenology of the air-ingress accident and to validate these models. Therefore, there is a need to design and construct a scaled-down experimental test facility to simulate the air-ingress accident scenarios and to collect experimental data. The current paper focuses on the analyses performed for the design and operation of a 1/8th geometric scale (by height and diameter), high-temperature test facility. A geometric scaling analysis for the VHTR, a time scale analysis of the air-ingress phenomenon, a transient depressurization analysis of the reactor vessel, a hydraulic similarity analysis of the test facility, a heat transfer characterization of the hot plenum, a power scaling analysis for the reactor system, and a design analysis of the containment vessel are discussed.« less

  10. Molecular Theory of Detonation Initiation: Insight from First Principles Modeling of the Decomposition Mechanisms of Organic Nitro Energetic Materials.

    PubMed

    Tsyshevsky, Roman V; Sharia, Onise; Kuklja, Maija M

    2016-02-19

    This review presents a concept, which assumes that thermal decomposition processes play a major role in defining the sensitivity of organic energetic materials to detonation initiation. As a science and engineering community we are still far away from having a comprehensive molecular detonation initiation theory in a widely agreed upon form. However, recent advances in experimental and theoretical methods allow for a constructive and rigorous approach to design and test the theory or at least some of its fundamental building blocks. In this review, we analyzed a set of select experimental and theoretical articles, which were augmented by our own first principles modeling and simulations, to reveal new trends in energetic materials and to refine known existing correlations between their structures, properties, and functions. Our consideration is intentionally limited to the processes of thermally stimulated chemical reactions at the earliest stage of decomposition of molecules and materials containing defects.

  11. Molecular Theory of Detonation Initiation: Insight from First Principles Modeling of the Decomposition Mechanisms of Organic Nitro Energetic Materials

    DOE PAGES

    Tsyshevsky, Roman; Sharia, Onise; Kuklja, Maija

    2016-02-19

    Our review presents a concept, which assumes that thermal decomposition processes play a major role in defining the sensitivity of organic energetic materials to detonation initiation. As a science and engineering community we are still far away from having a comprehensive molecular detonation initiation theory in a widely agreed upon form. However, recent advances in experimental and theoretical methods allow for a constructive and rigorous approach to design and test the theory or at least some of its fundamental building blocks. In this review, we analyzed a set of select experimental and theoretical articles, which were augmented by our ownmore » first principles modeling and simulations, to reveal new trends in energetic materials and to refine known existing correlations between their structures, properties, and functions. Lastly, our consideration is intentionally limited to the processes of thermally stimulated chemical reactions at the earliest stage of decomposition of molecules and materials containing defects.« less

  12. Frictional and hydraulic behaviour of carbonate fault gouge during fault reactivation - An experimental study

    NASA Astrophysics Data System (ADS)

    Delle Piane, Claudio; Giwelli, Ausama; Clennell, M. Ben; Esteban, Lionel; Nogueira Kiewiet, Melissa Cristina D.; Kiewiet, Leigh; Kager, Shane; Raimon, John

    2016-10-01

    We present a novel experimental approach devised to test the hydro-mechanical behaviour of different structural elements of carbonate fault rocks during experimental re-activation. Experimentally faulted core plugs were subject to triaxial tests under water saturated conditions simulating depletion processes in reservoirs. Different fault zone structural elements were created by shearing initially intact travertine blocks (nominal size: 240 × 110 × 150 mm) to a maximum displacement of 20 and 120 mm under different normal stresses. Meso-and microstructural features of these sample and the thickness to displacement ratio characteristics of their deformation zones allowed to classify them as experimentally created damage zones (displacement of 20 mm) and fault cores (displacement of 120 mm). Following direct shear testing, cylindrical plugs with diameter of 38 mm were drilled across the slip surface to be re-activated in a conventional triaxial configuration monitoring the permeability and frictional behaviour of the samples as a function of applied stress. All re-activation experiments on faulted plugs showed consistent frictional response consisting of an initial fast hardening followed by apparent yield up to a friction coefficient of approximately 0.6 attained at around 2 mm of displacement. Permeability in the re-activation experiments shows exponential decay with increasing mean effective stress. The rate of permeability decline with mean effective stress is higher in the fault core plugs than in the simulated damage zone ones. It can be concluded that the presence of gouge in un-cemented carbonate faults results in their sealing character and that leakage cannot be achieved by renewed movement on the fault plane alone, at least not within the range of slip measureable with our apparatus (i.e. approximately 7 mm of cumulative displacement). Additionally, it is shown that under sub seismic slip rates re-activated carbonate faults remain strong and no frictional weakening was observed during re-activation.

  13. Cosmological implications of quantum entanglement in the multiverse

    NASA Astrophysics Data System (ADS)

    Kanno, Sugumi

    2015-12-01

    We explore the cosmological implications of quantum entanglement between two causally disconnected universes in the multiverse. We first consider two causally separated de Sitter spaces with a state which is initially entangled. We derive the reduced density matrix of our universe and compute the spectrum of vacuum fluctuations. We then consider the same system with an initially non-entangled state. We find that due to quantum interference scale dependent modulations may enter the spectrum for the case of initially non-entangled state. This gives rise to the possibility that the existence of causally disconnected universes may be experimentally tested by analyzing correlators in detail.

  14. Hyper-X Research Vehicle (HXRV) Experimental Aerodynamics Test Program Overview

    NASA Technical Reports Server (NTRS)

    Holland, Scott D.; Woods, William C.; Engelund, Walter C.

    2000-01-01

    This paper provides an overview of the experimental aerodynamics test program to ensure mission success for the autonomous flight of the Hyper-X Research Vehicle (HXRV). The HXRV is a 12-ft long, 2700 lb lifting body technology demonstrator designed to flight demonstrate for the first time a fully airframe integrated scramjet propulsion system. Three flights are currently planned, two at Mach 7 and one at Mach 10, beginning in the fall of 2000. The research vehicles will be boosted to the prescribed scramjet engine test point where they will separate from the booster, stabilize. and initiate engine test. Following 5+ seconds of powered flight and 15 seconds of cowl-open tares, the cowl will close and the vehicle will fly a controlled deceleration trajectory which includes numerous control doublets for in-flight aerodynamic parameter identification. This paper reviews the preflight testing activities, wind tunnel models, test rationale. risk reduction activities, and sample results from wind tunnel tests supporting the flight trajectory of the HXRV from hypersonic engine test point through subsonic flight termination.

  15. Hyper-X Research Vehicle (HXRV) Experimental Aerodynamics Test Program Overview

    NASA Technical Reports Server (NTRS)

    Holland, Scott D.; Woods, William C.; Engelund, Walter C.

    2000-01-01

    This paper provides an overview of the experimental aerodynamics test program to ensure mission success for the autonomous flight of the Hyper-X Research Vehicle (HXRV). The HXRV is a 12-ft long, 2700 lb lifting body technology demonstrator designed to flight demonstrate for the first time a fully airframe integrated scramjet propulsion system. Three flights are currently planned, two at Mach 7 and one at Mach 10, beginning in the fall of 2000. The research vehicles will be boosted to the prescribed scramjet engine test point where they will separate from the booster, stabilize, and initiate engine test. Following 5+ seconds of powered flight and 15 seconds of cow-open tares, the cowl will close and the vehicle will fly a controlled deceleration trajectory which includes numerous control doublets for in-flight aerodynamic parameter identification. This paper reviews the preflight testing activities, wind tunnel models, test rationale, risk reduction activities, and sample results from wind tunnel tests supporting the flight trajectory of the HXRV from hypersonic engine test point through subsonic flight termination.

  16. Experimental Aerodynamic Derivatives of a Sinusoidally Oscillating Airfoil in Two-Dimensional Flow

    NASA Technical Reports Server (NTRS)

    Halfman, Robert L

    1952-01-01

    Experimental measurements of the aerodynamic reactions on a symmetrical airfoil oscillating harmonically in a two-dimensional flow are presented and analyzed. Harmonic motions include pure pitch and pure translation, for several amplitudes and superimposed on an initial angle of attack, as well as combined pitch and translation. The apparatus and testing program are described briefly and the necessary theoretical background is presented. In general, the experimental results agree remarkably well with the theory, especially in the case of the pure motions. The net work per cycle for a motion corresponding to flutter is experimentally determined to be zero. Considerable consistent data for pure pitch were obtained from a search of available reference material, and several definite Reynolds number effects are evident.

  17. 75 FR 15767 - Livability Initiative under Special Experimental Project No. 14

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-30

    ...] Livability Initiative under Special Experimental Project No. 14 AGENCY: Federal Highway Administration (FHWA... initiative to harmonize and coordinate the Federal-aid Highway Program with grant-in- aid programs... (EPA). Under this initiative, the FHWA intends to utilize Special Experimental Project No. 14 (SEP-14...

  18. Fatigue of notched fiber composite laminates. Part 2: Analytical and experimental evaluation

    NASA Technical Reports Server (NTRS)

    Kulkarni, S. V.; Mclaughlin, P. V., Jr.; Pipes, R. B.

    1976-01-01

    The analytical/experimental correlation study was performed to develop an understanding of the behavior of notched Boron/epoxy laminates subjected to tension/tension fatigue loading. It is postulated that the fatigue induced property changes (stiffness as well as strength) of the laminate can be obtained from the lamina fatigue properties. To that end, the Boron/epoxy lamina static and fatigue data (lifetime, residual stiffness and strength) were obtained initially. The longitudinal and transverse tension data were determined from the (0) and (90) laminate tests while the in-plane shear data were obtained from the (+ or - 45) sub s laminates. The static tests obtained the notched strength and mode of failure while the fatigue tests determined lifetime, damage propagation and residual strength. The failure in static tension occurred in a transverse crack propagation mode.

  19. Determination of necking time in tensile test specimens, under high-temperature creep conditions, subjected to distribution of stresses over the cross-section

    NASA Astrophysics Data System (ADS)

    Lokoshchenko, A.; Teraud, W.

    2018-04-01

    The work describes an experimental research of creep of cylindrical tensile test specimens made of aluminum alloy D16T at a constant temperature of 400°C. The issue to be examined was the necking at different values of initial tensile stresses. The use of a developed noncontacting measuring system allowed us to see variations in the specimen shape and to estimate the true stress in various times. Based on the obtained experimental data, several criteria were proposed for describing the point of time at which the necking occurs (necking point). Calculations were carried out at various values of the parameters in these criteria. The relative interval of deformation time in which the test specimen is uniformly stretched was also determined.

  20. Principles of Designing Interpretable Optogenetic Behavior Experiments

    ERIC Educational Resources Information Center

    Allen, Brian D.; Singer, Annabelle C.; Boyden, Edward S.

    2015-01-01

    Over the last decade, there has been much excitement about the use of optogenetic tools to test whether specific cells, regions, and projection pathways are necessary or sufficient for initiating, sustaining, or altering behavior. However, the use of such tools can result in side effects that can complicate experimental design or interpretation.…

  1. The Neural Basis of Insight Problem Solving: An Event-Related Potential Study

    ERIC Educational Resources Information Center

    Qiu, Jiang; Li, Hong; Yang, Dong; Luo, Yuejia; Li, Ying; Wu, Zhenzhen; Zhang, Qinglin

    2008-01-01

    The electrophysiological correlates of successful insight problem solving (Chinese logogriphs) were studied in 18 healthy subjects using high-density event-related potentials (ERPs). A new experimental paradigm (learning-testing model) was adopted in order to make subjects find a solution on their own initiative rather than receive an answer…

  2. Testing a Wheeled Landing Gear System for the TH-57 Helicopter

    DTIC Science & Technology

    1992-12-01

    initial comparison was done using a structural analysis program, GIFTS , to simultaneously analyze an~i compare the gear systems. Experimental data was used...15 B. GIFTS PROGRAM RESULTS ............................ 15 1. Model...Element Total System ( GIFTS ) structural analysis program, which is resident oin the Aeiunauimia Euginme1ing Department computer system, an analysis

  3. "First aid" for burned watersheds

    Treesearch

    J. S. Krammes; L. W. Hill

    1963-01-01

    Most of the vegetative cover on the San Dimas Experimental Forest was destroyed by a wildfire in 1960. Following the fire an emergency research program was initiated to test several "first -aid" treatments aimed at reducing flood and erosion damage from burned watersheds. This paper summarizes first - and second-year results of the research program.

  4. A test of critical thresholds and their indicators in a desertification-prone ecosystem: more resilience than we thought

    USDA-ARS?s Scientific Manuscript database

    Theoretical models predict that dryland ecosystems can cross critical thresholds after which vegetation loss is independent of initial drivers, but experimental data are nonexistent. We used a long-term (13 year) pulse-perturbation experiment featuring heavy grazing and shrub removal to determine i...

  5. Experimental Autoimmune Encephalomyelitis (EAE) as Animal Models of Multiple Sclerosis (MS).

    PubMed

    Glatigny, Simon; Bettelli, Estelle

    2018-01-08

    Multiple sclerosis (MS) is a multifocal demyelinating disease of the central nervous system (CNS) leading to the progressive destruction of the myelin sheath surrounding axons. It can present with variable clinical and pathological manifestations, which might reflect the involvement of distinct pathogenic processes. Although the mechanisms leading to the development of the disease are not fully understood, numerous evidences indicate that MS is an autoimmune disease, the initiation and progression of which are dependent on an autoimmune response against myelin antigens. In addition, genetic susceptibility and environmental triggers likely contribute to the initiation of the disease. At this time, there is no cure for MS, but several disease-modifying therapies (DMTs) are available to control and slow down disease progression. A good number of these DMTs were identified and tested using animal models of MS referred to as experimental autoimmune encephalomyelitis (EAE). In this review, we will recapitulate the characteristics of EAE models and discuss how they help shed light on MS pathogenesis and help test new treatments for MS patients. Copyright © 2018 Cold Spring Harbor Laboratory Press; all rights reserved.

  6. The performance of cleaner wrasse, Labroides dimidiatus, in a reversal learning task varies across experimental paradigms.

    PubMed

    Gingins, Simon; Marcadier, Fanny; Wismer, Sharon; Krattinger, Océane; Quattrini, Fausto; Bshary, Redouan; Binning, Sandra A

    2018-01-01

    Testing performance in controlled laboratory experiments is a powerful tool for understanding the extent and evolution of cognitive abilities in non-human animals. However, cognitive testing is prone to a number of potential biases, which, if unnoticed or unaccounted for, may affect the conclusions drawn. We examined whether slight modifications to the experimental procedure and apparatus used in a spatial task and reversal learning task affected performance outcomes in the bluestreak cleaner wrasse, Labroides dimidiatus (hereafter "cleaners"). Using two-alternative forced-choice tests, fish had to learn to associate a food reward with a side (left or right) in their holding aquarium. Individuals were tested in one of four experimental treatments that differed slightly in procedure and/or physical set-up. Cleaners from all four treatment groups were equally able to solve the initial spatial task. However, groups differed in their ability to solve the reversal learning task: no individuals solved the reversal task when tested in small tanks with a transparent partition separating the two options, whereas over 50% of individuals solved the task when performed in a larger tank, or with an opaque partition. These results clearly show that seemingly insignificant details to the experimental set-up matter when testing performance in a spatial task and might significantly influence the outcome of experiments. These results echo previous calls for researchers to exercise caution when designing methodologies for cognition tasks to avoid misinterpretations.

  7. Development and Certification of Station Development Test Objective (SDTO) Experiment # 15012-U, "Near RealTime Water Quality Monitoring Demonstration for ISS Biocides Using Colorimetric Solid Phase Extraction (CSPE)"

    NASA Technical Reports Server (NTRS)

    Gazda, Daniel B.; Nolan, Daniel J.; Rutz, Jeffrey A.; Shcultz, John R.; Siperko, Lorraine M.; Porter, Marc D,; Lipert, Robert J.; Limardo, Jose G.; McCoy, J. Torin

    2009-01-01

    Scientists and engineers from the Wyle Integrated Science and Engineering Group are working with researchers at the University of Utah and Iowa State University to develop and certify an experimental water quality monitoring kit based on Colorimetric Solid Phase Extraction (CSPE). The kit will be launched as a Station Development Test Objective (SDTO) experiment and evaluated on the International Space Station (ISS) to determine the acceptability of CSPE technology for routine inflight water quality monitoring. Iodine and silver, the biocides used in the US and Russian on-orbit water systems, will serve as test analytes for the technology evaluation. This manuscript provides an overview of the CSPE SDTO experiment and details the development and certification of the experimental water quality monitoring kit. Initial results from reagent and standard solution stability testing and environmental testing performed on the kit hardware are also reported.

  8. Effect of Shockwave Curvature on Run Distance Observed with a Modified Wedge Test

    NASA Astrophysics Data System (ADS)

    Lee, Richard; Dorgan, Robert; Sutherland, Gerrit; Benedetta, Ashley; Milby, Christopher

    2011-06-01

    The effect of wave curvature on shock initiation in PBXN-110 was investigated using a modified wedge test configuration. Various thicknesses of PBXN-110 donor slabs were used to define the shockwave curvature introduced to wedge samples of the same explosive. The donor slabs were initiated with line-wave generators so that the introduced shock would be the same shape, magnitude and duration across the entire input surface of the wedge. The shock parameters were varied for a given donor thickness via different widths of PMMA spacers placed between the donor and the wedge. A framing camera was used to observe where initiation occurred along the face of the wedge. Initiation always occurred at the center of the shock front instead of the sides like that reported by others using a much smaller test format. Results were compared to CTH calculations to indicate if there were effects associated with highly curved shock fronts that could not be adequately predicted. The run distance predicted in CTH for a 50.8 mm thick donor slab (low curvature) compared favorably with experimental results. However, results from thinner donor slabs (higher curvature) indicate a more sensitive behavior than the simulations predicted.

  9. Effect of shockwave curvature on run distance observed with a modified wedge test

    NASA Astrophysics Data System (ADS)

    Lee, Richard; Dorgan, Robert J.; Sutherland, Gerrit; Benedetta, Ashley; Milby, Christopher

    2012-03-01

    The effect of wave curvature on shock initiation in PBXN-110 was investigated using a modified wedge test configuration. Various widths of PBXN-110 donor slabs were used to define the shockwave curvature introduced to wedge samples of the same explosive. The donor slabs were initiated with line-wave generators so that the shock from the donor would be the same shape, magnitude and duration across the entire input surface of the wedge. The shock parameters were varied for a given donor with PMMA spacers placed between the donor and the wedge sample. A high-speed electronic framing camera was used to observe where initiation occurred along the face of the wedge. Initiation always occurred at the center of the shock front instead of along the sides like that reported by others using a much smaller test format. Results were compared to CTH calculations to indicate if there were effects associated with highly curved shock fronts that could not be adequately predicted. The run distance predicted in CTH for a 50.8 mm wide donor slab (low curvature) compared favorably with experimental results. However, results from thinner donor slabs (higher curvature) indicate a more sensitive behavior than the simulations predicted.

  10. Experimental Investigation of Shock Initiation in Mixtures of Manganese and Sulfur

    NASA Astrophysics Data System (ADS)

    Jette, Francois-Xavier; Goroshin, Sam; Higgins, Andrew

    2009-06-01

    Equimolar mixtures of manganese powder and sulfur at different initial densities were tested in two different types of steel recovery capsules in order to study the shock initiation phenomenon in SHS mixtures. This mixture composition was selected due to the large exothermic heat release of the manganese-sulfur reaction (214 kJ/mol), which causes the reaction to be self-sustaining once initiated. Two different sizes of Mn particles were used for these experiments, 1-5 μm and -325 mesh (44μm or less). The test samples were placed in planar recovery ampoules and a strong shock was delivered via the detonation of a charge of amine-sensitized nitromethane. Various shock strengths were achieved by placing different thicknesses of PMMA attenuator discs between the explosive charge and the ampoule. The results confirmed that shock-induced reactions can be produced in highly non-porous mixtures. It was also found that shock interactions with the side walls of the recovery capsule can play a significant role in the initiation, and that mixtures containing the larger Mn particles were very difficult to initiate in the absence of shock interactions with the capsule walls.

  11. Experimental Protocol to Determine the Chloride Threshold Value for Corrosion in Samples Taken from Reinforced Concrete Structures

    PubMed Central

    Angst, Ueli M.; Boschmann, Carolina; Wagner, Matthias; Elsener, Bernhard

    2017-01-01

    The aging of reinforced concrete infrastructure in developed countries imposes an urgent need for methods to reliably assess the condition of these structures. Corrosion of the embedded reinforcing steel is the most frequent cause for degradation. While it is well known that the ability of a structure to withstand corrosion depends strongly on factors such as the materials used or the age, it is common practice to rely on threshold values stipulated in standards or textbooks. These threshold values for corrosion initiation (Ccrit) are independent of the actual properties of a certain structure, which clearly limits the accuracy of condition assessments and service life predictions. The practice of using tabulated values can be traced to the lack of reliable methods to determine Ccrit on-site and in the laboratory. Here, an experimental protocol to determine Ccrit for individual engineering structures or structural members is presented. A number of reinforced concrete samples are taken from structures and laboratory corrosion testing is performed. The main advantage of this method is that it ensures real conditions concerning parameters that are well known to greatly influence Ccrit, such as the steel-concrete interface, which cannot be representatively mimicked in laboratory-produced samples. At the same time, the accelerated corrosion test in the laboratory permits the reliable determination of Ccrit prior to corrosion initiation on the tested structure; this is a major advantage over all common condition assessment methods that only permit estimating the conditions for corrosion after initiation, i.e., when the structure is already damaged. The protocol yields the statistical distribution of Ccrit for the tested structure. This serves as a basis for probabilistic prediction models for the remaining time to corrosion, which is needed for maintenance planning. This method can potentially be used in material testing of civil infrastructures, similar to established methods used for mechanical testing. PMID:28892023

  12. Experimental Protocol to Determine the Chloride Threshold Value for Corrosion in Samples Taken from Reinforced Concrete Structures.

    PubMed

    Angst, Ueli M; Boschmann, Carolina; Wagner, Matthias; Elsener, Bernhard

    2017-08-31

    The aging of reinforced concrete infrastructure in developed countries imposes an urgent need for methods to reliably assess the condition of these structures. Corrosion of the embedded reinforcing steel is the most frequent cause for degradation. While it is well known that the ability of a structure to withstand corrosion depends strongly on factors such as the materials used or the age, it is common practice to rely on threshold values stipulated in standards or textbooks. These threshold values for corrosion initiation (Ccrit) are independent of the actual properties of a certain structure, which clearly limits the accuracy of condition assessments and service life predictions. The practice of using tabulated values can be traced to the lack of reliable methods to determine Ccrit on-site and in the laboratory. Here, an experimental protocol to determine Ccrit for individual engineering structures or structural members is presented. A number of reinforced concrete samples are taken from structures and laboratory corrosion testing is performed. The main advantage of this method is that it ensures real conditions concerning parameters that are well known to greatly influence Ccrit, such as the steel-concrete interface, which cannot be representatively mimicked in laboratory-produced samples. At the same time, the accelerated corrosion test in the laboratory permits the reliable determination of Ccrit prior to corrosion initiation on the tested structure; this is a major advantage over all common condition assessment methods that only permit estimating the conditions for corrosion after initiation, i.e., when the structure is already damaged. The protocol yields the statistical distribution of Ccrit for the tested structure. This serves as a basis for probabilistic prediction models for the remaining time to corrosion, which is needed for maintenance planning. This method can potentially be used in material testing of civil infrastructures, similar to established methods used for mechanical testing.

  13. RDHWT/MARIAH II Hypersonic Wind Tunnel Research Program

    DTIC Science & Technology

    2008-09-01

    Diagnostics Dr. Gary Brown – Gas Dynamics Dr. Ihab Girgis – Modeling Dr. Dennis Mansfield – Experimental Ring Technical Services Dr. Leon Ring – Systems...wind tunnel (MSHWT) with Mach 8 to 15, true -temperature flight test capabilities. This research program was initiated in fiscal year (FY) 1998 and is...Force test capabilities that exist today. Performance goals of the MSHWT are true temperature, Mach 8 to 15, dynamic pressure of 500 to 2000 psf (24 to

  14. Multiaxial constitutive behavior of an interstitial-free steel: Measurements through X-ray and digital image correlation

    PubMed Central

    Jeong, Y.; Iadicola, M.A.; Gnäupel-Herold, T.; Creuziger, A.

    2017-01-01

    Constitutive behaviors of an interstitial-free steel sample were measured using an augmented Marciniak experiment. In these tests, multiaxial strain field data of the flat specimens were measured by the digital image correlation technique. In addition, the flow stress was measured using an X-ray diffractometer. The flat specimens in three different geometries were tested in order to achieve 1) balanced biaxial strain, and plane strain tests with zero strain in either 2) rolling direction or 3) transverse direction. The multiaxial stress and strain data were processed to obtain plastic work contours with reference to a uniaxial tension test along the rolling direction. The experimental results show that the mechanical behavior of the subjected specimen deviates significantly from isotropic behavior predicted by the von Mises yield criterion. The initial yield loci measured by a Marciniak tester is in good agreement with what is predicted by Hill's yield criterion. However, as deformation increases beyond the vonMises strain of 0.05, the shape of the work contour significantly deviates from that of Hill's yield locus. A prediction made by a viscoplastic self-consistent model is in better agreement with the experimental observation than the Hill yield locus with the isotropic work-hardening rule. However, none of the studied models matched the initial or evolving anisotropic behaviors of the interstitial-free steel measured by the augmented Marciniak experiment. PMID:28690400

  15. Multiaxial constitutive behavior of an interstitial-free steel: Measurements through X-ray and digital image correlation.

    PubMed

    Jeong, Y; Iadicola, M A; Gnäupel-Herold, T; Creuziger, A

    2016-06-15

    Constitutive behaviors of an interstitial-free steel sample were measured using an augmented Marciniak experiment. In these tests, multiaxial strain field data of the flat specimens were measured by the digital image correlation technique. In addition, the flow stress was measured using an X-ray diffractometer. The flat specimens in three different geometries were tested in order to achieve 1) balanced biaxial strain, and plane strain tests with zero strain in either 2) rolling direction or 3) transverse direction. The multiaxial stress and strain data were processed to obtain plastic work contours with reference to a uniaxial tension test along the rolling direction. The experimental results show that the mechanical behavior of the subjected specimen deviates significantly from isotropic behavior predicted by the von Mises yield criterion. The initial yield loci measured by a Marciniak tester is in good agreement with what is predicted by Hill's yield criterion. However, as deformation increases beyond the vonMises strain of 0.05, the shape of the work contour significantly deviates from that of Hill's yield locus. A prediction made by a viscoplastic self-consistent model is in better agreement with the experimental observation than the Hill yield locus with the isotropic work-hardening rule. However, none of the studied models matched the initial or evolving anisotropic behaviors of the interstitial-free steel measured by the augmented Marciniak experiment.

  16. Structural Analysis and Testing of an Erectable Truss for Precision Segmented Reflector Application

    NASA Technical Reports Server (NTRS)

    Collins, Timothy J.; Fichter, W. B.; Adams, Richard R.; Javeed, Mehzad

    1995-01-01

    This paper describes analysis and test results obtained at Langley Research Center (LaRC) on a doubly curved testbed support truss for precision reflector applications. Descriptions of test procedures and experimental results that expand upon previous investigations are presented. A brief description of the truss is given, and finite-element-analysis models are described. Static-load and vibration test procedures are discussed, and experimental results are shown to be repeatable and in generally good agreement with linear finite-element predictions. Truss structural performance (as determined by static deflection and vibration testing) is shown to be predictable and very close to linear. Vibration test results presented herein confirm that an anomalous mode observed during initial testing was due to the flexibility of the truss support system. Photogrammetric surveys with two 131-in. reference scales show that the root-mean-square (rms) truss-surface accuracy is about 0.0025 in. Photogrammetric measurements also indicate that the truss coefficient of thermal expansion (CTE) is in good agreement with that predicted by analysis. A detailed description of the photogrammetric procedures is included as an appendix.

  17. ENHANCED PRACTICAL PHOTOSYNTHETIC CO2 MITIGATION

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

    Dr. Gregory Kremer; Dr. David J. Bayless; Dr. Morgan Vis

    2001-07-25

    This quarterly report documents significant achievements in the Enhanced Practical Photosynthetic CO{sub 2} Mitigation project during the period from 4/03/2001 through 7/02/2001. Most of the achievements are milestones in our efforts to complete the tasks and subtasks that constitute the project objectives. Note that this version of the quarterly technical report is a revision to add the reports from subcontractors Montana State and Oak Ridge National Laboratories The significant accomplishments for this quarter include: Development of an experimental plan and initiation of experiments to create a calibration curve that correlates algal chlorophyll levels with carbon levels (to simplify future experimentalmore » procedures); Completion of debugging of the slug flow reactor system, and development of a plan for testing the pressure drop of the slug flow reactor; Design and development of a new bioreactor screen design which integrates the nutrient delivery drip system and the harvesting system; Development of an experimental setup for testing the new integrated drip system/harvesting system; Completion of model-scale bioreactor tests examining the effects of CO{sub 2} concentration levels and lighting levels on Nostoc 86-3 growth rates; Completion of the construction of a larger model-scale bioreactor to improve and expand testing capabilities and initiation of tests; Substantial progress on construction of a pilot-scale bioreactor; and Preliminary economic analysis of photobioreactor deployment. Plans for next quarter's work are included in the conclusions. A preliminary economic analysis is included as an appendix.« less

  18. Non-local classical optical correlation and implementing analogy of quantum teleportation

    PubMed Central

    Sun, Yifan; Song, Xinbing; Qin, Hongwei; Zhang, Xiong; Yang, Zhenwei; Zhang, Xiangdong

    2015-01-01

    This study reports an experimental realization of non-local classical optical correlation from the Bell's measurement used in tests of quantum non-locality. Based on such a classical Einstein–Podolsky–Rosen optical correlation, a classical analogy has been implemented to the true meaning of quantum teleportation. In the experimental teleportation protocol, the initial teleported information can be unknown to anyone and the information transfer can happen over arbitrary distances. The obtained results give novel insight into quantum physics and may open a new field of applications in quantum information. PMID:25779977

  19. Initial characterization of an Experimental Referee Broadened-Specification (ERBS) aviation turbine fuel

    NASA Technical Reports Server (NTRS)

    Prok, G. M.; Seng, G. T.

    1980-01-01

    Characterization data and a hydrocarbon compositional analysis are presented for a research test fuel designated as an experimental referee broadened-specification aviation turbine fuel. This research fuel, which is a special blend of kerosene and hydrotreated catalytic gas oil, is a hypothetical representation of a future fuel should it become necessary to broaden current kerojet specifications. It is used as a reference fuel in research investigations into the effects of fuel property variations on the performance and durability of jet aircraft components, including combustors and fuel systems.

  20. Experimental Exploration on Rainfall-induced Mass Re-mobilization after Giant Earthquake: A case study in Wenchuan earthquake hit region, China

    NASA Astrophysics Data System (ADS)

    Yang, Zongji; Bogaard, Thom. A.; Qiao, Jianping; Jiang, Yuanjun

    2015-04-01

    Prevention and mitigation of rainfall induced geological hazards after the Ms=8 Wenchuan earthquake on May 12th, 2008 were gained more significance for the rebuild of earthquake hit regions in China. After the Wenchuan earthquake, there were thousands of slopes failure, which were much more susceptible to subsequent heavy rainfall and many even transformed into potential debris flows. An typical example can be found in the catastrophic disaster occurred in Zhongxing County, Chengdu City on 10th July, 2013 in which the unknown fractured slope up the mountain was triggered by a downpour and transformed into subsequent debris flow which wiped the community downstream, about 200 victims were reported in that tragic event. The transform patterns of rainfall-induced mass re-mobilization was categorized into three major type as the erosion of fractured slopes, initiate on loosen deposit and outbreak of landslide (debris flow) dams according to vast field investigation in the earthquake hit region. Despite the widespread and hidden characters,the complexity of the process also demonstrated in the transforms of the mass re-mobilized by the erosion of both gravity and streams in the small watersheds which have never been reported before the giant Wenchuan Earthquake in many regions. As a result, an increasing number of questions for disaster relief and mitigation were proposed including the threshold of early warning and measurement of the volume for the design of mitigation measures on rainfall-induced mass re-mobilization in debris flow gullies. This study is aimed for answer the essential questions about the threshold and amount of mass initiation triggered by the subsequent rainfall in post earthquake time. In this study, experimental tests were carried out for simulating the failure of the rainfall-induced mass re-mobilization in respectively in a natural co-seismic fractured slope outside and the debris flow simulation platform inside the laboratory. A natural fractured slope was selected to conduct the field experimental test,after the field experimental test, the correlation of rainfall parameters, deformation criterion and water content as well as the failure volume of gravity erosion was investigated. In addition, the loosen mass re-mobilized by the stream was also simulated by the model experiment by which the correlation of rainfall thresholds, and the initial volume of mass triggered by the flow was analyzed. Thus, the threshold and volume measurement model for the initiation of mass re-mobilization were proposed by means of this experimental research. Despite of the fact that the simplicity of the model derived from experimental and empirical method and some drawbacks connected with the uncertainty and complexity of the geological phenomenon, the proposed method have contributed a lot in application for the early warning and prevention of mass transformed debris flows in earthquake hit region, China.

  1. Initial stages of cavitation damage and erosion on copper and brass tested in a rotating disk device

    NASA Technical Reports Server (NTRS)

    Rao, P. V.; Rao, B. C. S.; Rao, N. S. L.

    1982-01-01

    In view of the differences in flow and experimental conditions, there has been a continuing debate as to whether or not the ultrasonic method of producing cavitation damage is similar to the damage occurring in cavitating flow systems, namely, venturi and rotating disk devices. In this paper, the progress of cavitation damage during incubation periods on polycrystalline copper and brass tested in a rotating disk device is presented. The results indicate several similarities and differences in the damage mechanism encountered in a rotating disk device (which simulates field rotary devices) and a magnetostriction apparatus. The macroscopic erosion appears similar to that in the vibratory device except for nonuniform erosion and apparent plastic flow during the initial damage phase.

  2. Statistical model specification and power: recommendations on the use of test-qualified pooling in analysis of experimental data

    PubMed Central

    Colegrave, Nick

    2017-01-01

    A common approach to the analysis of experimental data across much of the biological sciences is test-qualified pooling. Here non-significant terms are dropped from a statistical model, effectively pooling the variation associated with each removed term with the error term used to test hypotheses (or estimate effect sizes). This pooling is only carried out if statistical testing on the basis of applying that data to a previous more complicated model provides motivation for this model simplification; hence the pooling is test-qualified. In pooling, the researcher increases the degrees of freedom of the error term with the aim of increasing statistical power to test their hypotheses of interest. Despite this approach being widely adopted and explicitly recommended by some of the most widely cited statistical textbooks aimed at biologists, here we argue that (except in highly specialized circumstances that we can identify) the hoped-for improvement in statistical power will be small or non-existent, and there is likely to be much reduced reliability of the statistical procedures through deviation of type I error rates from nominal levels. We thus call for greatly reduced use of test-qualified pooling across experimental biology, more careful justification of any use that continues, and a different philosophy for initial selection of statistical models in the light of this change in procedure. PMID:28330912

  3. Experimental and computational data from a small rocket exhaust diffuser

    NASA Astrophysics Data System (ADS)

    Stephens, Samuel E.

    1993-06-01

    The Diagnostics Testbed Facility (DTF) at the NASA Stennis Space Center in Mississippi is a versatile facility that is used primarily to aid in the development of nonintrusive diagnostics for liquid rocket engine testing. The DTF consists of a fixed, 1200 lbf thrust, pressure fed, liquid oxygen/gaseous hydrogen rocket engine, and associated support systems. An exhaust diffuser has been fabricated and installed to provide subatmospheric pressures at the exit of the engine. The diffuser aerodynamic design was calculated prior to fabrication using the PARC Navier-Stokes computational fluid dynamics code. The diffuser was then fabricated and tested at the DTF. Experimental data from these tests were acquired to determine the operational characteristics of the system and to correlate the actual and predicted flow fields. The results show that a good engineering approximation of overall diffuser performance can be made using the PARC Navier-Stokes code and a simplified geometry. Correlations between actual and predicted cell pressure and initial plume expansion in the diffuser are good; however, the wall pressure profiles do not correlate as well with the experimental data.

  4. Experimental Investigations And Numerical Modelling of 210CR12 Steel in Semi-Solid State

    NASA Astrophysics Data System (ADS)

    Macioł, Piotr; Zalecki, Władysław; Kuziak, Roman; Jakubowicz, Aleksandra; Weglarczyk, Stanisław

    2011-05-01

    Experimental investigation, including hot compression and simple closed die filling was performed. Temperature range of tests was between 1225 °C and 1320 °C. Temperature selection was adequate with liquid fraction between 20 and 60%, which is typical for thixoforming processes. In the die filling test, steel dies with ceramic layer was used (highly refractory air-setting mortar JM 3300 manufactured by Thermal Ceramics). Experiments were carried out on the Gleeble 3800 physical simulator with MCU unit. In the paper, methodology of experimental investigation is described. Dependency of forming forces on temperature and forming velocities is analysed. Obtained results are discussed. The second part of the paper concerns numerical modelling of semi-solid forming. Numerical models for both sets of test were developed. Structural and Computational Fluid Dynamics models are compared. Initial works in microstructural modelling of 210CR12 steel behaviour are described. Lattice Boltzman Method model for thixotropic flows is introduced. Microscale and macroscale models were integrated into multiscale simulation of semi-solid forming. Some fundamental issues related to multiscale modelling of thixoforming are discussed.

  5. Experimental design approach to the optimization of ultrasonic degradation of alachlor and enhancement of treated water biodegradability.

    PubMed

    Torres, Ricardo A; Mosteo, Rosa; Pétrier, Christian; Pulgarin, Cesar

    2009-03-01

    This work presents the application of experimental design for the ultrasonic degradation of alachlor which is pesticide classified as priority substance by the European Commission within the scope of the Water Framework Directive. The effect of electrical power (20-80W), pH (3-10) and substrate concentration (10-50mgL(-1)) was evaluated. For a confidential level of 90%, pH showed a low effect on the initial degradation rate of alachlor; whereas electrical power, pollutant concentration and the interaction of these two parameters were significant. A reduced model taking into account the significant variables and interactions between variables has shown a good correlation with the experimental results. Additional experiments conducted in natural and deionised water indicated that the alachlor degradation by ultrasound is practically unaffected by the presence of potential *OH radical scavengers: bicarbonate, sulphate, chloride and oxalic acid. In both cases, alachlor was readily eliminated ( approximately 75min). However, after 4h of treatment only 20% of the initial TOC was removed, showing that alachlor by-products are recalcitrant to the ultrasonic action. Biodegradability test (BOD5/COD) carried out during the course of the treatment indicated that the ultrasonic system noticeably increases the biodegradability of the initial solution.

  6. Experimental temporal quantum steering

    PubMed Central

    Bartkiewicz, Karol; Černoch, Antonín; Lemr, Karel; Miranowicz, Adam; Nori, Franco

    2016-01-01

    Temporal steering is a form of temporal correlation between the initial and final state of a quantum system. It is a temporal analogue of the famous Einstein-Podolsky-Rosen (spatial) steering. We demonstrate, by measuring the photon polarization, that temporal steering allows two parties to verify if they have been interacting with the same particle, even if they have no information about what happened with the particle in between the measurements. This is the first experimental study of temporal steering. We also performed experimental tests, based on the violation of temporal steering inequalities, of the security of two quantum key distribution protocols against individual attacks. Thus, these results can lead to applications for secure quantum communications and quantum engineering. PMID:27901121

  7. Initiation and propagation of mixed mode fractures in granite and sandstone

    NASA Astrophysics Data System (ADS)

    Rück, Marc; Rahner, Roman; Sone, Hiroki; Dresen, Georg

    2017-10-01

    We investigate mixed mode fracture initiation and propagation in experimentally deformed granite and sandstone. We performed a series of asymmetric loading tests to induce fractures in cylindrical specimens at confining pressures up to 20 MPa. Loading was controlled using acoustic emission (AE) feedback control, which allows studying quasi-static fracture propagation for several hours. Location of acoustic emissions reveals distinct differences in spatial-temporal fracture evolution between granite and sandstone samples. Before reaching peak stress in experiments performed on granite, axial fractures initiate first at the edge of the indenter and then propagate through the entire sample. Secondary inclined fractures develop during softening of the sample. In sandstone, inclined shear fractures nucleate at peak stress and propagate through the specimen. AE source type analysis shows complex fracturing in both materials with pore collapse contributing significantly to fracture growth in sandstone samples. We compare the experimental results with numerical models to analyze stress distribution and energy release rate per unit crack surface area in the samples at different stages during fracture growth. We thereby show that for both rock types the energy release rate increases approximately linearly during fracture propagation. The study illuminates how different material properties modify fracture initiation direction under similar loading conditions.

  8. Computational Analysis of the Transonic Dynamics Tunnel Using FUN3D

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

    Chwalowski, Pawel; Quon, Eliot; Brynildsen, Scott E.

    This paper presents results from an explanatory two-year effort of applying Computational Fluid Dynamics (CFD) to analyze the empty-tunnel flow in the NASA Langley Research Center Transonic Dynamics Tunnel (TDT). The TDT is a continuous-flow, closed circuit, 16- x 16-foot slotted-test-section wind tunnel, with capabilities to use air or heavy gas as a working fluid. In this study, experimental data acquired in the empty tunnel using the R-134a test medium was used to calibrate the computational data. The experimental calibration data includes wall pressures, boundary-layer profiles, and the tunnel centerline Mach number profiles. Subsonic and supersonic flow regimes were considered,more » focusing on Mach 0.5, 0.7 and Mach 1.1 in the TDT test section. This study discusses the computational domain, boundary conditions, and initial conditions selected in the resulting steady-state analyses using NASA's FUN3D CFD software.« less

  9. Benchmark cyclic plastic notch strain measurements

    NASA Technical Reports Server (NTRS)

    Sharpe, W. N., Jr.; Ward, M.

    1983-01-01

    Plastic strains at the roots of notched specimens of Inconel 718 subjected to tension-compression cycling at 650 C are reported. These strains were measured with a laser-based technique over a gage length of 0.1 mm and are intended to serve as 'benchmark' data for further development of experimental, analytical, and computational approaches. The specimens were 250 mm by 2.5 mm in the test section with double notches of 4.9 mm radius subjected to axial loading sufficient to cause yielding at the notch root on the tensile portion of the first cycle. The tests were run for 1000 cycles at 10 cpm or until cracks initiated at the notch root. The experimental techniques are described, and then representative data for the various load spectra are presented. All the data for each cycle of every test are available on floppy disks from NASA.

  10. Computational Analysis of the Transonic Dynamics Tunnel Using FUN3D

    NASA Technical Reports Server (NTRS)

    Chwalowski, Pawel; Quon, Eliot; Brynildsen, Scott E.

    2016-01-01

    This paper presents results from an exploratory two-year effort of applying Computational Fluid Dynamics (CFD) to analyze the empty-tunnel flow in the NASA Langley Research Center Transonic Dynamics Tunnel (TDT). The TDT is a continuous-flow, closed circuit, 16- x 16-foot slotted-test-section wind tunnel, with capabilities to use air or heavy gas as a working fluid. In this study, experimental data acquired in the empty tunnel using the R-134a test medium was used to calibrate the computational data. The experimental calibration data includes wall pressures, boundary-layer profiles, and the tunnel centerline Mach number profiles. Subsonic and supersonic flow regimes were considered, focusing on Mach 0.5, 0.7 and Mach 1.1 in the TDT test section. This study discusses the computational domain, boundary conditions, and initial conditions selected and the resulting steady-state analyses using NASA's FUN3D CFD software.

  11. Hot tearing studies in AA5182

    NASA Astrophysics Data System (ADS)

    van Haaften, W. M.; Kool, W. H.; Katgerman, L.

    2002-10-01

    One of the major problems during direct chill (DC) casting is hot tearing. These tears initiate during solidification of the alloy and may run through the entire ingot. To study the hot tearing mechanism, tensile tests were carried out in semisolid state and at low strain rates, and crack propagation was studied in situ by scanning electron microscopy (SEM). These experimentally induced cracks were compared with hot tears developed in an AA5182 ingot during a casting trial in an industrial research facility. Similarities in the microstructure of the tensile test specimens and the hot tears indicate that hot tearing can be simulated by performing tensile tests at semisolid temperatures. The experimental data were compared with existing hot tearing models and it was concluded that the latter are restricted to relatively high liquid fractions because they do not take into account the existence of solid bridges in the crack.

  12. Target Soil Impact Verification: Experimental Testing and Kayenta Constitutive Modeling.

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

    Broome, Scott Thomas; Flint, Gregory Mark; Dewers, Thomas

    2015-11-01

    This report details experimental testing and constitutive modeling of sandy soil deformation under quasi - static conditions. This is driven by the need to understand constitutive response of soil to target/component behavior upon impact . An experimental and constitutive modeling program was followed to determine elastic - plastic properties and a compressional failure envelope of dry soil . One hydrostatic, one unconfined compressive stress (UCS), nine axisymmetric compression (ACS) , and one uniaxial strain (US) test were conducted at room temperature . Elastic moduli, assuming isotropy, are determined from unload/reload loops and final unloading for all tests pre - failuremore » and increase monotonically with mean stress. Very little modulus degradation was discernable from elastic results even when exposed to mean stresses above 200 MPa . The failure envelope and initial yield surface were determined from peak stresses and observed onset of plastic yielding from all test results. Soil elasto - plastic behavior is described using the Brannon et al. (2009) Kayenta constitutive model. As a validation exercise, the ACS - parameterized Kayenta model is used to predict response of the soil material under uniaxial strain loading. The resulting parameterized and validated Kayenta model is of high quality and suitable for modeling sandy soil deformation under a range of conditions, including that for impact prediction.« less

  13. Career Planning Modules for the Officer Career Information and Planning System.

    ERIC Educational Resources Information Center

    Phillips, Susan D.; And Others

    This discussion of the modules in an experimental computer-aided system for officer career information and planning system (OCIPS) includes the reasons for its development, a description of the seven modules, and the findings of a preliminary test of four of the modules for feasibility and credibility. Initially developed in response to a need…

  14. Differential Effects of Context and Feedback on Orthographic Learning: How Good Is Good Enough?

    ERIC Educational Resources Information Center

    Martin-Chang, Sandra; Ouellette, Gene; Bond, Linda

    2017-01-01

    In this study, students in Grade 2 read different sets of words under 4 experimental training conditions (context/feedback, isolation/feedback, context/no-feedback, isolation/no-feedback). Training took place over 10 trials, followed by a spelling test and a delayed reading posttest. Reading in context boosted reading accuracy initially; in…

  15. Programmatic background, site description, experimental approach and treatment, and natural disturbances

    Treesearch

    Wayne T. Swank; Jackson Webster

    2014-01-01

    This volume is a synthesis of a long-term interdisciplinary study of watershed ecosystem responses to a forest-management disturbance. Specifically, a commercial clearcut cable logging experiment was initiated on Watershed 7 (WS 7) at the Coweeta Hydrologic Laboratory in 1975 to elucidate ecosystem structure and function by testing hypotheses associated with the...

  16. Invasion resistance and persistence: established plants win, even with disturbance and high propagule pressure

    Treesearch

    Christopher M. McGlone; Carolyn Hull Sieg; Thomas E. Kolb

    2011-01-01

    Disturbances and propagule pressure are key mechanisms in plant community resistance to invasion, as well as persistence of invasions. Few studies, however, have experimentally tested the interaction of these two mechanisms. We initiated a study in a southwestern ponderosa pine (Pinus ponderosa Laws.)/bunch grass system to determine the susceptibility of remnant native...

  17. Experimental Packet Radio System Design Plan

    DTIC Science & Technology

    1974-03-13

    specific design parameters (packet format, data rates, modulation type, spread factor, etc.) for the initial system configuration. c. Prototype...are described along with size, weight and power estimates, and projections of per- formance parameters . d. Measurement and Test. The plan...are presented covering the communications link, system parameters , and various levels of network operation and performance. This plan is a snapshot

  18. Influence of humidity on the initial emittable concentration of formaldehyde and hexaldehyde in building materials: experimental observation and correlation.

    PubMed

    Huang, Shaodan; Xiong, Jianyin; Cai, Chaorui; Xu, Wei; Zhang, Yinping

    2016-03-30

    Humidity is one of the main environmental factors affecting the emission rate and key parameters of formaldehyde and volatile organic compounds (VOCs) from building materials. Meanwhile, the initial emittable concentration (Cm,0) is proved to be the most sensitive key parameter to the emission behaviours. However, there is no report on the relationship between humidity and Cm,0. In this paper, Cm,0 of formaldehyde and hexaldehyde from a type of medium density fiberboard in absolute humidity (AH) range of 4.6-19.6 g/m(3) at 25 °C were tested by virtue of a C-history method. Experimental results indicate that Cm,0 is dramatically dependent on AH, increased by 10 and 2 times for formaldehyde and hexaldehyde when AH rising from 4.6 g/m(3) to 19.6 g/m(3). A linear relationship between the logarithm of Cm,0 and AH is obtained based on the measured results. In addition, a correlation characterizing the association of emission rate and AH is derived. The effectiveness of the correlation is verified with our experimental results as well as data from literature. With the correlations, the Cm,0 or emission rate different from the test AH conditions can be conveniently obtained. This study should be useful for predicting the emission characteristics of humidity changing scenarios and for source control.

  19. Hypersonic research engine/aerothermodynamic integration model, experimental results. Volume 1: Mach 6 component integration

    NASA Technical Reports Server (NTRS)

    Andrews, E. H., Jr.; Mackley, E. A.

    1976-01-01

    The NASA Hypersonic Research Engine (HRE) Project was initiated for the purpose of advancing the technology of airbreathing propulsion for hypersonic flight. A large component (inlet, combustor, and nozzle) and structures development program was encompassed by the project. The tests of a full-scale (18 in. diameter cowl and 87 in. long) HRE concept, designated the Aerothermodynamic Integration Model (AIM), at Mach numbers of 5, 6, and 7. Computer program results for Mach 6 component integration tests are presented.

  20. International Aerospace and Ground Conference on Lightning and Static Electricity (8th): Lightning Technology Roundup, held at Fort Worth, Texas on 21-23 June 1983.

    DTIC Science & Technology

    1983-06-01

    fighter aircraft. The entire test bed is from testing of a representative digital supported above the ground plane by non - control system(s)l e.g... control and Increased systems Integration a. Raw data must be collected and Introduce new requirements for protection, experimental setups and An accurate...presented, several possible solutions to the grounding prob! - are suggested. All rely on establishing initial ground contact through a controlled non -zero

  1. Improved Healing of Large, Osseous, Segmental Defects by Reverse Dynamization: Evaluation in a Sheep Model

    DTIC Science & Technology

    2014-10-01

    initiated. One such fixator has been tested on a cadaveric sheep tibia. In the unlocked, loose position, the axial stiffness of the tibia and fixator...suggested by our previous studies using rats. This aspect of the project is the present focus of attention, and additional cadaver legs will be tested...characterize external fixators). A 3 mm tibial defect was created in the leg of a cadaveric sheep, and stabilized with an experimental external

  2. Motivation and performance in physical education: an experimental test.

    PubMed

    Moreno, Juan A; González-Cutre, David; Martín-Albo, José; Cervelló, Eduardo

    2010-01-01

    The purpose of this study was to analyse, experimentally, the relationships between motivation and performance in a lateral movement test in physical education. The study group consisted of 363 students (227 boys and 136 girls), aged between 12 and 16, who were randomly divided into three groups: an experimental group in which an incremental ability belief was induced, another experimental group in which an entity ability belief was induced, and a control group where there was no intervention. Measurements were made of situational intrinsic motivation, perceived competence in executing the task and performance. The results revealed that the incremental group reported higher scores on the situational intrinsic motivation scale. The entity group demonstrated better performance in the first test attempt than the incremental group but, in the second attempt, the performance was similar in the different groups. Perhaps the initial differences in performance disappeared because the incremental group counted on improving in the second attempt. These results are discussed in relation to the intensity with which the teacher conveys information relating to incremental ability belief of the pupil to increase intrinsic motivation and performance. Key pointsThe incremental group showed more situational intrinsic motivation.The entity group showed higher performance in the first test attempt, but significant differences disappeared in the second attempt.It seems that this incremental belief and greater intrinsic motivation made the students trust they would improve their performance in the second attempt at the lateral movement test.

  3. TRAC-PF1 code verification with data from the OTIS test facility. [Once-Through Intergral System

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

    Childerson, M.T.; Fujita, R.K.

    1985-01-01

    A computer code (TRAC-PF1/MOD1) developed for predicting transient thermal and hydraulic integral nuclear steam supply system (NSSS) response was benchmarked. Post-small break loss-of-coolant accident (LOCA) data from a scaled, experimental facility, designated the One-Through Integral System (OTIS), were obtained for the Babcock and Wilcox NSSS and compared to TRAC predictions. The OTIS tests provided a challenging small break LOCA data set for TRAC verification. The major phases of a small break LOCA observed in the OTIS tests included pressurizer draining and loop saturation, intermittent reactor coolant system circulation, boiler-condenser mode, and the initial stages of refill. The TRAC code wasmore » successful in predicting OTIS loop conditions (system pressures and temperatures) after modification of the steam generator model. In particular, the code predicted both pool and auxiliary-feedwater initiated boiler-condenser mode heat transfer.« less

  4. WHEN ONSET MEETS DESISTANCE: COGNITIVE TRANSFORMATION AND ADOLESCENT MARIJUANA EXPERIMENTATION*

    PubMed Central

    Kreager, Derek A.; Ragan, Daniel T.; Nguyen, Holly; Staff, Jeremy

    2016-01-01

    Purpose Desistance scholars primarily focus on changing social roles, cognitive transformations, and shifting identities to understand the cessation of serious crime and illicit drug use in adulthood. In the current study, we move the spotlight away from adulthood and toward adolescence, the developmental stage when the prevalence of offending and substance use peak and desistance from most of these behaviors begins. Our primary hypothesis is that changes in perceived psychic rewards surrounding initial forays into marijuana use strongly predict adolescents’ decisions to cease or persist that behavior. In addition, based on social learning expectations, we hypothesize that peer perceptions and behaviors provide mechanisms for perceptual change. Methods We test these hypotheses using longitudinal data of marijuana use, perceptions, and peer networks from the PROmoting School-community-university Partnerships to Enhance Resilience (PROSPER) study. We estimate hazard models of marijuana initiation and within-person models of perceptual updating for youth from grades 6 to 12 (n=6,154). Results We find that changes in marijuana’s perceived psychic rewards surrounding initiation differentiated experimenters from persisters. Experimenters had significantly lower updated perceptions of marijuana as a fun behavior compared to persisters and these perceptions dropped after the initiation wave. In contrast, persisters updated their perceptions in upward directions and maintained more positive perceptions over time. Inconsistent with social learning expectations, initiators’ updated perceptions of marijuana as a fun activity were not explained by peer-reported behaviors or attitudes. PMID:27478762

  5. On the mechanical stability of porous coated press fit titanium implants: a finite element study of a pushout test.

    PubMed

    Helgason, Benedikt; Viceconti, Marco; Rúnarsson, Tómas P; Brynjólfsson, Sigurour

    2008-01-01

    Pushout tests can be used to estimate the shear strength of the bone implant interface. Numerous such experimental studies have been published in the literature. Despite this researchers are still some way off with respect to the development of accurate numerical models to simulate implant stability. In the present work a specific experimental pushout study from the literature was simulated using two different bones implant interface models. The implant was a porous coated Ti-6Al-4V retrieved 4 weeks postoperatively from a dog model. The purpose was to find out which of the interface models could replicate the experimental results using physically meaningful input parameters. The results showed that a model based on partial bone ingrowth (ingrowth stability) is superior to an interface model based on friction and prestressing due to press fit (initial stability). Even though the present study is limited to a single experimental setup, the authors suggest that the presented methodology can be used to investigate implant stability from other experimental pushout models. This would eventually enhance the much needed understanding of the mechanical response of the bone implant interface and help to quantify how implant stability evolves with time.

  6. Understanding of visual attention by adult humans (Homo sapiens): a partial replication of Povinelli, Bierschwale, and Cech (1999).

    PubMed

    Thomas, Emily; Murphy, Mary; Pitt, Rebecca; Rivers, Angela; Leavens, David A

    2008-11-01

    Povinelli, Bierschwale, and Cech (1999) reported that when tested on a visual attention task, the behavior of juvenile chimpanzees did not support a high-level understanding of visual attention. This study replicates their research using adult humans and aims to investigate the validity of their experimental design. Participants were trained to respond to pointing cues given by an experimenter, and then tested on their ability to locate hidden objects from visual cues. Povinelli et al.'s assertion that the generalization of pointing to gaze is indicative of a high-level framework was not supported by our findings: Training improved performance only on initial probe trials when the experimenter's gaze was not directed at the baited cup. Furthermore, participants performed above chance on such trials, the same result exhibited by chimpanzees and used as evidence by Povinelli et al. to support a low-level framework. These findings, together with the high performance of participants in an incongruent condition, in which the experimenter pointed to or gazed at an unbaited container, challenge the validity of their experimental design. (PsycINFO Database Record (c) 2008 APA, all rights reserved).

  7. Experimental design and response surface modelling for optimization of vat dye from water by nano zero valent iron (NZVI).

    PubMed

    Arabi, Simin; Sohrabi, Mahmoud Reza

    2013-01-01

    In this study, NZVI particles was prepared and studied for the removal of vat green 1 dye from aqueous solution. A four-factor central composite design (CCD) combined with response surface modeling (RSM) to evaluate the combined effects of variables as well as optimization was employed for maximizing the dye removal by prepared NZVI based on 30 different experimental data obtained in a batch study. Four independent variables, viz. NZVI dose (0.1-0.9 g/L), pH (1.5-9.5), contact time (20-100 s), and initial dye concentration (10-50 mg/L) were transform to coded values and quadratic model was built to predict the responses. The significant of independent variables and their interactions were tested by the analysis of variance (ANOVA). Adequacy of the model was tested by the correlation between experimental and predicted values of the response and enumeration of prediction errors. The ANOVA results indicated that the proposed model can be used to navigate the design space. Optimization of the variables for maximum adsorption of dye by NZVI particles was performed using quadratic model. The predicted maximum adsorption efficiency (96.97%) under the optimum conditions of the process variables (NZVI dose 0.5 g/L, pH 4, contact time 60 s, and initial dye concentration 30 mg/L) was very close to the experimental value (96.16%) determined in batch experiment. In the optimization, R2 and R2adj correlation coefficients for the model were evaluated as 0.95 and 0.90, respectively.

  8. Innovative use of influential prenatal counseling may improve breastfeeding initiation rates among WIC participants.

    PubMed

    Hildebrand, Deana A; McCarthy, Pam; Tipton, Debi; Merriman, Connie; Schrank, Melody; Newport, Melinda

    2014-01-01

    To determine whether integrating influence strategies (reciprocation, consistency, consensus, feeling liked, authority, and scarcity) throughout Chickasaw Nation Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) clinics (1) changed participants' perception of the WIC experience and (2) affected breastfeeding initiation rates. Two-part, quasi-experimental design. Four WIC clinics. Parents and caregivers of children birth to 3 years. Behavior change intervention based on Social Cognitive Theory using Caildini's Principles of Influence. Traditional-model groups (control) received services prior to the intervention; influence-model groups (experimental) received services after initiation of the intervention. The preliminary demonstration project surveyed 2 groups to measure changes in their perceptions of the WIC environment. Secondary data analysis measured changes in breastfeeding initiation in 2 groups of postpartum women. Frequency analysis, independent sample t tests, chi-square for independence, step-wise logistic regression. The demonstration project resulted in 5 improved influence measures (P < .02), aligning with the influence principle of "feeling liked." The model had a small effect (φ = 0.10) in distinguishing breastfeeding initiation; women in the influence model were 1.5 times more likely (95% CI, 1.19-1.86; P < .05) to initiate breastfeeding compared with women in the traditional model, controlling for parity, mother's age, and race. Consistent with Social Cognitive Theory, changing the WIC environment by integrating influence principles may positively affect women's infant feeding decisions and behaviors, specifically breastfeeding initiation rates. Copyright © 2014 Society for Nutrition Education and Behavior. Published by Elsevier Inc. All rights reserved.

  9. Benchmark tests for a Formula SAE Student car prototyping

    NASA Astrophysics Data System (ADS)

    Mariasiu, Florin

    2011-12-01

    Aerodynamic characteristics of a vehicle are important elements in its design and construction. A low drag coefficient brings significant fuel savings and increased engine power efficiency. In designing and developing vehicles trough computer simulation process to determine the vehicles aerodynamic characteristics are using dedicated CFD (Computer Fluid Dynamics) software packages. However, the results obtained by this faster and cheaper method, are validated by experiments in wind tunnels tests, which are expensive and were complex testing equipment are used in relatively high costs. Therefore, the emergence and development of new low-cost testing methods to validate CFD simulation results would bring great economic benefits for auto vehicles prototyping process. This paper presents the initial development process of a Formula SAE Student race-car prototype using CFD simulation and also present a measurement system based on low-cost sensors through which CFD simulation results were experimentally validated. CFD software package used for simulation was Solid Works with the FloXpress add-on and experimental measurement system was built using four piezoresistive force sensors FlexiForce type.

  10. Metal matrix composites: Testing, analysis, and failure modes; Proceedings of the Symposium, Sparks, NV, Apr. 25, 26, 1988

    NASA Technical Reports Server (NTRS)

    Johnson, W. S. (Editor)

    1989-01-01

    The present conference discusses the tension and compression testing of MMCs, the measurement of advanced composites' thermal expansion, plasticity theory for fiber-reinforced composites, a deformation analysis of boron/aluminum specimens by moire interferometry, strength prediction methods for MMCs, and the analysis of notched MMCs under tensile loading. Also discussed are techniques for the mechanical and thermal testing of Ti3Al/SCS-6 MMCs, damage initiation and growth in fiber-reinforced MMCs, the shear testing of MMCs, the crack growth and fracture of continuous fiber-reinforced MMCs in view of analytical and experimental results, and MMC fiber-matrix interface failures.

  11. Impact-initiated damage thresholds in composites

    NASA Technical Reports Server (NTRS)

    Sharma, A. V.

    1980-01-01

    An experimental investigation was conducted to study the effect of low velocity projectile impact on the sandwich-type structural components. The materials used in the fabrication of the impact surface were graphite-, Kevlar-, and boron-fibers with appropriate epoxy matrices. The testing of the specimens was performed at moderately low- and high-temperatures as well as at room temperature to assess the impact-initiated strength degradation of the laminates. Eleven laminates with different stacking sequences, orientations, and thicknesses were tested. The low energy projectile impact is considered to simulate the damage caused by runway debris, dropping of the hand tools during servicing, etc., on the secondary aircraft structures fabricated with the composite materials. The results show the preload and the impact energy combinations necessary to cause catastrophic failures in the laminates tested. A set of faired curves indicating the failure thresholds is shown separately for the tension- and compression-loaded laminates. The specific-strengths and -moduli for the various laminates tested are also given.

  12. Efficacy of a footbath for post-partum fatigue in South Korea: A quasi-experimental study.

    PubMed

    Choi, Eunsun; Song, Eunju

    2017-04-01

    The purpose of this study was to identify the effects of a footbath on post-partum fatigue. This study used a quasi-experimental design by using an unequivalent control group, pre-post-test design. The participants were divided into experimental and control groups. Fifty post-partum women who were admitted to an obstetrics and gynecology ward of a general hospital were the experimental group and 50 post-partum women who were admitted to an obstetrics and gynecology ward of a women's hospital were the control group. Two hospitals were providing similar postnatal care to their patients and they were located in the same city. The experimental group received a footbath along with postnatal care at the hospital, while the control group received only postnatal care from the hospital. Each group completed the Fatigue Continuum Form at a specified time. The general characteristics and pretest dependent variables were homogenous between the two groups. The hypothesis was supported post-test as the Fatigue Continuum Form scores differed significantly between the experimental and the control groups. This study showed that a footbath helps to decrease fatigue among post-partum women. In addition, it is a good preventative strategy for post-partum women who should initiate it in the early post-partum period. © 2016 Japan Academy of Nursing Science.

  13. Low thrust rocket test facility

    NASA Technical Reports Server (NTRS)

    Arrington, Lynn A.; Schneider, Steven J.

    1990-01-01

    A low thrust chemical rocket test facility has recently become operational at the NASA-Lewis. The new facility is used to conduct both long duration and performance tests at altitude over a thruster's operating envelope using hydrogen and oxygen gas for propellants. The facility provides experimental support for a broad range of objectives, including fundamental modeling of fluids and combustion phenomena, the evaluation of thruster components, and life testing of full rocket designs. The major mechanical and electrical systems are described along with aspects of the various optical diagnostics available in the test cell. The electrical and mechanical systems are designed for low down time between tests and low staffing requirements for test operations. Initial results are also presented which illustrate the various capabilities of the cell.

  14. Acceleration of Intended Pozzolanic Reaction under Initial Thermal Treatment for Developing Cementless Fly Ash Based Mortar.

    PubMed

    Kwon, Yang-Hee; Kang, Sung-Hoon; Hong, Sung-Gul; Moon, Juhyuk

    2017-02-24

    Without using strong alkaline solution or ordinary Portland cement, a new structural binder consisting of fly ash and hydrated lime was hardened through an intensified pozzolanic reaction. The main experimental variables are the addition of silica fume and initial thermal treatment (60 °C for 3 days). A series of experiments consisting of mechanical testing (compressive and flexural strength, modulus of elasticity), X-ray diffraction, and measurements of the heat of hydration, pore structure, and shrinkage were conducted. These tests show that this new fly ash-based mortar has a compressive strength of 15 MPa at 91 days without any silica fume addition or initial thermal treatment. The strength increased to over 50 MPa based on the acceleration of the intensified pozzolanic reaction from the silica fume addition and initial thermal treatment. This is explained by a significant synergistic effect induced by the silica fume. It intensifies the pozzolanic reaction under thermal treatment and provides a space filling effect. This improved material performance can open a new pathway to utilize the industrial by-product of fly ash in cementless construction materials.

  15. 76 FR 66698 - Postsecondary Educational Institutions Invited To Participate in Experiments Under the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-27

    ... Experiments Under the Experimental Sites Initiative AGENCY: Office of Postsecondary Education, Department of... institutions to participate in experiments under the Experimental Sites Initiative. SUMMARY: The Secretary... participate in one or more new experiments under the Experimental Sites Initiative (ESI), as authorized by...

  16. Press-fit acetabular cup fixation: principles and testing.

    PubMed

    Macdonald, W; Carlsson, L V; Charnley, G J; Jacobsson, C M

    1999-01-01

    Pre-clinical testing of the fixation of press-fit acetabular components of total hip prostheses relies on cadaver or synthetic bone, but the properties and geometry of bone models differ from those of physiological bone. Cup designs use varied mechanisms for initial stability in bone; therefore, using different analogues and tests is appropriate. Press-fit cup stability was tested in the following: firstly, polyurethane (PU) foam modelling cancellous support; secondly, glass-fibre reinforced epoxide (GFRE) tubes modelling acetabular cortical support; thirdly, cadaveric acetabula. Three commercial cups [Harris-Galante II (H-G-II), Zimmer; Optifix, Smith & Nephew, Richards; porous coated anatomic (PCA), Howmedica] and an experimental cup with enhanced rim fixation were tested in three modes: direct pull-out, lever-out and axial torque. The fixation stabilities measured in the PU and the GFRE models showed trends consistent with those in cadaver bone, differing in the oversizing and cup geometry. The experimental cup was significantly more secure in most modes than other cups; the H-G II and Optifix cups showed similar stabilities, lower than that of the experimental cup but greater than that of the PCA cup (analysis of variance and Tukey's highly significant test; p < 0.001). The stabilities measured in cadaver bone more closely approximated those in GFRE. The use of several bone analogues enables separation of fixation mechanisms, allowing more accurate prediction of in vivo performance.

  17. Space Shuttle Tail Service Mast Concept Verification

    NASA Technical Reports Server (NTRS)

    Uda, R. T.

    1976-01-01

    Design studies and analyses were performed to describe the loads and dynamics of the space shuttle tail service masts (TSMs). Of particular interest are the motion and interaction of the umbilical carrier plate, lanyard system, vacuum jacketed hoses, latches, links, and masthead. A development test rig was designed and fabricated to obtain experimental data. The test program is designed to (1) verify the theoretical dynamics calculations, (2) prove the soundness of design concepts, and (3) elucidate problem areas (if any) in the design of mechanisms and structural components. Design, fabrication, and initiation of TSM development testing at Kennedy Space Center are described.

  18. Expansion tube test time predictions

    NASA Technical Reports Server (NTRS)

    Gourlay, Christopher M.

    1988-01-01

    The interaction of an interface between two gases and strong expansion is investigated and the effect on flow in an expansion tube is examined. Two mechanisms for the unsteady Pitot-pressure fluctuations found in the test section of an expansion tube are proposed. The first mechanism depends on the Rayleigh-Taylor instability of the driver-test gas interface in the presence of a strong expansion. The second mechanism depends on the reflection of the strong expansion from the interface. Predictions compare favorably with experimental results. The theory is expected to be independent of the absolute values of the initial expansion tube filling pressures.

  19. Distinguishing intentional from accidental actions in orangutans (Pongo pygmaeus), chimpanzees (Pan troglodytes), and human children (Homo sapiens).

    PubMed

    Call, J; Tomasello, M

    1998-06-01

    This study investigates the understanding of others' intentions in 2- and 3-year-old children, chimpanzees (Pan troglodytes), and orangutans (Pongo pygmaeus). During training, subjects learned to use a discriminative cue to select a baited box. During testing, the experimenter placed a marker on top of the baited box to inform the subject of the reward's location. However, the experimenter also accidentally dropped the marker on top of an unbaited box, so that during any given trial the experimenter marked 2 boxes, 1 intentionally and 1 accidentally. All 3 species preferentially selected the box the experimenter had marked intentionally (especially during the initial trials), with 3-year-old children presenting the most robust results. These findings suggest that subjects understood something about the experimenter's intentions. The authors speculate that understanding of others' intentions may precede the understanding of others' beliefs both at the ontogenetic and phylogenetic levels.

  20. NiTi Alloy Negator Springs for Long-Stroke Constant-Force Shape Memory Actuators: Modeling, Simulation and Testing

    NASA Astrophysics Data System (ADS)

    Spaggiari, Andrea; Dragoni, Eugenio; Tuissi, Ausonio

    2014-07-01

    This work aims at the experimental characterization and modeling validation of shape memory alloy (SMA) Negator springs. According to the classic engineering books on springs, a Negator spring is a spiral spring made of strip of metal wound on the flat with an inherent curvature such that, in repose, each coil wraps tightly on its inner neighbor. The main feature of a Negator springs is the nearly constant force displacement behavior in the unwinding of the strip. Moreover the stroke is very long, theoretically infinite, as it depends only on the length of the initial strip. A Negator spring made in SMA is built and experimentally tested to demonstrate the feasibility of this actuator. The shape memory Negator spring behavior can be modeled with an analytical procedure, which is in good agreement with the experimental test and can be used for design purposes. In both cases, the material is modeled as elastic in austenitic range, while an exponential continuum law is used to describe the martensitic behavior. The experimental results confirms the applicability of this kind of geometry to the shape memory alloy actuators, and the analytical model is confirmed to be a powerful design tool to dimension and predict the spring behavior both in martensitic and austenitic range.

  1. Effect of prolonged and exclusive breast feeding on risk of allergy and asthma: cluster randomised trial.

    PubMed

    Kramer, Michael S; Matush, Lidia; Vanilovich, Irina; Platt, Robert; Bogdanovich, Natalia; Sevkovskaya, Zinaida; Dzikovich, Irina; Shishko, Gyorgy; Mazer, Bruce

    2007-10-20

    To assess whether exclusive and prolonged breast feeding reduces the risk of childhood asthma and allergy by age 6.5 years. Cluster randomised trial. 31 Belarussian maternity hospitals and their affiliated polyclinics. A total of 17,046 mother-infant pairs were enrolled, of whom 13,889 (81.5%) were followed up at age 6.5 years. Breastfeeding promotion intervention modelled on the WHO/UNICEF baby friendly hospital initiative. International study of asthma and allergies in childhood (ISAAC) questionnaire and skin prick tests of five inhalant antigens. The experimental intervention led to a large increase in exclusive breast feeding at 3 months (44.3% v 6.4%; P<0.001) and a significantly higher prevalence of any breast feeding at all ages up to and including 12 months. The experimental group had no reduction in risks of allergic symptoms and diagnoses or positive skin prick tests. In fact, after exclusion of six sites (three experimental and three control) with suspiciously high rates of positive skin prick tests, risks were significantly increased in the experimental group for four of the five antigens. These results do not support a protective effect of prolonged and exclusive breast feeding on asthma or allergy. Current Controlled Trials ISRCTN37687716 [controlled-trials.com].

  2. CeSOX: An experimental test of the sterile neutrino hypothesis with Borexino

    NASA Astrophysics Data System (ADS)

    Gromov, M.; Agostini, M.; Altenmüller, K.; Appel, S.; Atroshchenko, V.; Bagdasarian, Z.; Basilico, D.; Bellini, G.; Benziger, J.; Bick, D.; Bonfini, G.; Bravo, D.; Caccianiga, B.; Calaprice, F.; Caminata, A.; Caprioli, S.; Carlini, M.; Cavalcante, P.; Chepurnov, A.; Choi, K.; Cloué, O.; Collica, L.; Cribier, M.; D'Angelo, D.; Davini, S.; Derbin, A.; Ding, X. F.; Di Ludovico, A.; Di Noto, L.; Drachnev, I.; Durero, M.; Farinon, S.; Fischer, V.; Fomenko, K.; Formozov, A.; Franco, D.; Gabriele, F.; Gaffiot, J.; Galbiati, C.; Gschwender, M.; Ghiano, C.; Giammarchi, M.; Goretti, A.; Guffanti, D.; Hagner, C.; Houdy, T.; Hungerford, E.; Ianni, Aldo; Ianni, Andrea; Jonquères, N.; Jany, A.; Jeschke, D.; Kobychev, V.; Korablev, D.; Korga, G.; Kornoukhov, V.; Kryn, D.; Lachenmaier, T.; Lasserre, T.; Laubenstein, M.; Litvinovich, E.; Lombardi, F.; Lombardi, P.; Ludhova, L.; Lukyanchenko, G.; Lukyanchenko, L.; Machulin, I.; Manuzio, G.; Marcocci, S.; Maricic, J.; Mention, G.; Martyn, J.; Meroni, E.; Meyer, M.; Miramonti, L.; Misiaszek, M.; Muratova, V.; Musenich, R.; Neumair, B.; Oberauer, L.; Opitz, B.; Orekhov, V.; Ortica, F.; Pallavicini, M.; Papp, L.; Penek, Ö.; Pilipenko, N.; Pocar, A.; Porcelli, A.; Ranucci, G.; Razeto, A.; Re, A.; Redchuk, M.; Romani, A.; Roncin, R.; Rossi, N.; Rottenanger, S.; Schönert, S.; Scola, L.; Semenov, D.; Skorokhvatov, M.; Smirnov, O.; Sotnikov, A.; Stokes, L. F. F.; Suvorov, Y.; Tartaglia, R.; Testera, G.; Thurn, J.; Toropova, M.; Trantel, A.; Unzhakov, E.; Veyssiére, C.; Vishneva, A.; Vivier, M.; Vogelaar, R. B.; von Feilitzsch, F.; Wang, H.; Weinz, S.; Wojcik, M.; Wurm, M.; Yokley, Z.; Zaimidoroga, O.; Zavatarelli, S.; Zuber, K.; Zuzel, G.

    2017-12-01

    The third phase of the Borexino experiment that’s referred to as SOX is devoted to test the hypothesis of the existence of one (or more) sterile neutrinos at a short baseline (~5-10m). The experimental measurement will be made with artificial sources namely with a 144Ce-144Pr antineutrino source at the first stage (CeSOX) and possibly with a 51Cr neutrino source at the second one. The fixed 144Ce-144Pr sample will be placed beneath the detector in a special pit and the initial activity will be about 100 - 150 kCi. The start of data taking is scheduled for April 2018. The article gives a short description of the preparation for the first stage and shows the expected sensitivity.

  3. Comparison of Analytical Predictions and Experimental Results for a Dual Brayton Power System

    NASA Technical Reports Server (NTRS)

    Johnson, Paul

    2007-01-01

    NASA Glenn Research Center (GRC) contracted Barber- Nichols, Arvada, CO to construct a dual Brayton power conversion system for use as a hardware proof of concept and to validate results from a computational code known as the Closed Cycle System Simulation (CCSS). Initial checkout tests were performed at Barber- Nichols to ready the system for delivery to GRC. This presentation describes the system hardware components and lists the types of checkout tests performed along with a couple issues encountered while conducting the tests. A description of the CCSS model is also presented. The checkout tests did not focus on generating data, therefore, no test data or model analyses are presented.

  4. Advanced thermionic energy conversion

    NASA Technical Reports Server (NTRS)

    Britt, E. J.; Fitzpatrick, G. D.; Hansen, L. K.; Rasor, N. S.

    1974-01-01

    Basic analytical and experimental exploration was conducted on several types of advanced thermionic energy converters, and preliminary analysis was performed on systems utilizing advanced converter performance. The Pt--Nb cylindrical diode which exhibited a suppressed arc drop, as described in the preceding report, was reassembled and the existence of the postulated hydrid mode of operation was tentatively confirmed. Initial data obtained on ignited and unignited triode operation in the demountable cesium vapor system essentially confirmed the design principles developed in earlier work, with a few exceptions. Three specific advanced converter concepts were selected as candidates for concentrated basic study and for practical evaluation in fixed-configuration converters. Test vehicles and test stands for these converters and a unique controlled-atmosphere station for converter assembly and processing were designed, and procurement was initiated.

  5. Issues, concerns, and initial implementation results for space based telerobotic control

    NASA Technical Reports Server (NTRS)

    Lawrence, D. A.; Chapel, J. D.; Depkovich, T. M.

    1987-01-01

    Telerobotic control for space based assembly and servicing tasks presents many problems in system design. Traditional force reflection teleoperation schemes are not well suited to this application, and the approaches to compliance control via computer algorithms have yet to see significant testing and comparison. These observations are discussed in detail, as well as the concerns they raise for imminent design and testing of space robotic systems. As an example of the detailed technical work yet to be done before such systems can be specified, a particular approach to providing manipulator compliance is examined experimentally and through modeling and analysis. This yields some initial insight into the limitations and design trade-offs for this class of manipulator control schemes. Implications of this investigation for space based telerobots are discussed in detail.

  6. Cascade heterogeneous face sketch-photo synthesis via dual-scale Markov Network

    NASA Astrophysics Data System (ADS)

    Yao, Saisai; Chen, Zhenxue; Jia, Yunyi; Liu, Chengyun

    2018-03-01

    Heterogeneous face sketch-photo synthesis is an important and challenging task in computer vision, which has widely applied in law enforcement and digital entertainment. According to the different synthesis results based on different scales, this paper proposes a cascade sketch-photo synthesis method via dual-scale Markov Network. Firstly, Markov Network with larger scale is used to synthesise the initial sketches and the local vertical and horizontal neighbour search (LVHNS) method is used to search for the neighbour patches of test patches in training set. Then, the initial sketches and test photos are jointly entered into smaller scale Markov Network. Finally, the fine sketches are obtained after cascade synthesis process. Extensive experimental results on various databases demonstrate the superiority of the proposed method compared with several state-of-the-art methods.

  7. False memories for dissonance inducing events.

    PubMed

    Rodriguez, Dario N; Strange, Deryn

    2015-01-01

    Memories serve as a "database" of the self and people often produce distorted memories that support their self-concepts. One, surprisingly untested, possibility is that cognitive dissonance may be one mechanism by which people may misremember their past. We tested this hypothesis using an induced-compliance paradigm: participants either chose or were forced to write a counterattitudinal essay supporting a tuition increase and were afforded the opportunity to reduce dissonance via attitude shift or denial of responsibility. They then reported their memories for the experimental instructions and their initial attitudes (assessed two days prior to the laboratory session). Participants who chose to write the essay exhibited the predicted attitude-shift effect, and were more likely to misremember their initial attitudes and the experimental instruction than those who were forced to write the essay. Overall, our results provide evidence that cognitive dissonance may yield memory distortion, filling a significant gap in the motivated cognition and memory literatures.

  8. A comparison of experimental and calculated thin-shell leading-edge buckling due to thermal stresses

    NASA Technical Reports Server (NTRS)

    Jenkins, Jerald M.

    1988-01-01

    High-temperature thin-shell leading-edge buckling test data are analyzed using NASA structural analysis (NASTRAN) as a finite element tool for predicting thermal buckling characteristics. Buckling points are predicted for several combinations of edge boundary conditions. The problem of relating the appropriate plate area to the edge stress distribution and the stress gradient is addressed in terms of analysis assumptions. Local plasticity was found to occur on the specimen analyzed, and this tended to simplify the basic problem since it effectively equalized the stress gradient from loaded edge to loaded edge. The initial loading was found to be difficult to select for the buckling analysis because of the transient nature of thermal stress. Multiple initial model loadings are likely required for complicated thermal stress time histories before a pertinent finite element buckling analysis can be achieved. The basic mode shapes determined from experimentation were correctly identified from computation.

  9. Microstructural Effects on Initiation Behavior in HMX

    NASA Astrophysics Data System (ADS)

    Molek, Christopher; Welle, Eric; Hardin, Barrett; Vitarelli, Jim; Wixom, Ryan; Samuels, Philip

    Understanding the role microstructure plays on ignition and growth behavior has been the subject of a significant body of research within the detonation physics community. The pursuit of this understanding is important because safety and performance characteristics have been shown to strongly correlate to particle morphology. Historical studies have often correlated bulk powder characteristics to the performance or safety characteristics of pressed materials. We believe that a clearer and more relevant correlation is made between the pressed microstructure and the observed detonation behavior. This type of assessment is possible, as techniques now exist for the quantification of the pressed microstructures. Our talk will report on experimental efforts that correlate directly measured microstructural characteristics to initiation threshold behavior of HMX based materials. The internal microstructures were revealed using an argon ion cross-sectioning technique. This technique enabled the quantification of density and interface area of the pores within the pressed bed using methods of stereology. These bed characteristics are compared to the initiation threshold behavior of three HMX based materials using an electric gun based test method. Finally, a comparison of experimental threshold data to supporting theoretical efforts will be made.

  10. Verification of RELAP5-3D code in natural circulation loop as function of the initial water inventory

    NASA Astrophysics Data System (ADS)

    Bertani, C.; Falcone, N.; Bersano, A.; Caramello, M.; Matsushita, T.; De Salve, M.; Panella, B.

    2017-11-01

    High safety and reliability of advanced nuclear reactors, Generation IV and Small Modular Reactors (SMR), have a crucial role in the acceptance of these new plants design. Among all the possible safety systems, particular efforts are dedicated to the study of passive systems because they rely on simple physical principles like natural circulation, without the need of external energy source to operate. Taking inspiration from the second Decay Heat Removal system (DHR2) of ALFRED, the European Generation IV demonstrator of the fast lead cooled reactor, an experimental facility has been built at the Energy Department of Politecnico di Torino (PROPHET facility) to study single and two-phase flow natural circulation. The facility behavior is simulated using the thermal-hydraulic system code RELAP5-3D, which is widely used in nuclear applications. In this paper, the effect of the initial water inventory on natural circulation is analyzed. The experimental time behaviors of temperatures and pressures are analyzed. The experimental matrix ranges between 69 % and 93%; the influence of the opposite effects related to the increase of the volume available for the expansion and the pressure raise due to phase change is discussed. Simulations of the experimental tests are carried out by using a 1D model at constant heat power and fixed liquid and air mass; the code predictions are compared with experimental results. Two typical responses are observed: subcooled or two phase saturated circulation. The steady state pressure is a strong function of liquid and air mass inventory. The numerical results show that, at low initial liquid mass inventory, the natural circulation is not stable but pulsated.

  11. Monomer-to-polymer conversion and micro-tensile bond strength to dentine of experimental and commercial adhesives containing diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide or a camphorquinone/amine photo-initiator system.

    PubMed

    Miletic, Vesna; Pongprueksa, Pong; De Munck, Jan; Brooks, Neil R; Van Meerbeek, Bart

    2013-10-01

    To compare the degree of conversion (DC) of adhesives initiated by diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) or a camphorquinone/tertiary amine system (CQ/Amine) as well as their 'immediate' micro-tensile bond strength (μTBS) to bur-cut dentine. DC of Scotchbond Universal ('SBU'; 3M ESPE), its experimental counterpart containing TPO as photo-initiator system, an experimental G-aenial Bond ('Ga-B'; GC) adhesive formulation, and an experimental LUB-102 adhesive formulation ('LUB', Kuraray Noritake), containing as photo-initiatior system either 2wt% CQ along with 2wt% tertiary amine ('SBU_CQ/Amine'; 'Ga-B_CQ/Amine'; 'LUB_CQ/Amine'), or 2wt% TPO ('SBU_TPO'; 'Ga-B_TPO'; 'LUB_TPO'), was determined using Fourier-transform infrared spectroscopy (FTIR), after being cured with a dual-wavelength light-curing unit (bluephase 20i, Ivoclar Vivadent). The same adhesive formulations were applied to bur-cut mid-coronal dentine of intact human molars, and subjected to a μTBS test after 1-week water storage. Besides being applied following a self-etch (SE) application mode, the adhesive formulations SBU_CQ/Amine and SBU_TPO were also applied following an etch-and-rinse (E&R) mode, this both for DS and μTBS measurement. No significant difference in DC was found for any of the adhesive formulations, except for SBU_CQ/Amine_SE and SBU_TPO_SE. For both SBU formulations, a significantly higher DC was reached for the E&R than the SE approach. Regarding μTBS, no significant differences were recorded, except for the significantly higher μTBS measured for SBU_CQ/Amine_E&R and SBU_TPO_E&R. In self-etch adhesives, the photo-initiator TPO may be used instead of CQ/Amine. The curing and 'immediate' bonding efficiency depended on the application protocol (E&R versus SE), but not on the photo-initiator system. The photo-initiator TPO may be used in self-etch adhesives instead of CQ/Amine with similar curing and 'immediate' bonding efficiency. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. The visual cliff's forgotten menagerie: rats, goats, babies, and myth-making in the history of psychology.

    PubMed

    Rodkey, Elissa N

    2015-01-01

    Eleanor Gibson and Richard Walk's famous visual cliff experiment is one of psychology's classic studies, included in most introductory textbooks. Yet the famous version which centers on babies is actually a simplification, the result of disciplinary myth-making. In fact the visual cliff's first subjects were rats, and a wide range of animals were tested on the cliff, including chicks, turtles, lambs, kid goats, pigs, kittens, dogs, and monkeys. The visual cliff experiment was more accurately a series of experiments, employing varying methods and a changing apparatus, modified to test different species. This paper focuses on the initial, nonhuman subjects of the visual cliff, resituating the study in its original experimental logic, connecting it to the history of comparative psychology, Gibson's interest in comparative psychology, as well as gender-based discrimination. Recovering the visual cliff's forgotten menagerie helps to counter the romanticization of experimentation by focusing on the role of extrascientific factors, chance, complexity, and uncertainty in the experimental process. © 2015 Wiley Periodicals, Inc.

  13. An experimental microcomputer controlled system for synchronized pulsating anti-gravity suit.

    PubMed

    Moore, T W; Foley, J; Reddy, B R; Kepics, F; Jaron, D

    1987-07-01

    An experimental system to deliver synchronized external pressure pulsations to the lower body is described in this technical note. The system is designed using a microcomputer with a real time interface and an electro-pneumatic subsystem capable of delivering pressure pulses to a modified anti-G suit at a fast rate. It is versatile, containing many options for synchronizing, phasing and sequencing of the pressure pulsations and controlling the pressure level in the suit bladders. Details of its software and hardware are described along with the results of initial testing in a Dynamic Flight Simulator on human volunteers.

  14. Modeling of circulating fluised beds for post-combustion carbon capture

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

    Lee, A.; Shadle, L.; Miller, D.

    2011-01-01

    A compartment based model for a circulating fluidized bed reactor has been developed based on experimental observations of riser hydrodynamics. The model uses a cluster based approach to describe the two-phase behavior of circulating fluidized beds. Fundamental mass balance equations have been derived to describe the movement of both gas and solids though the system. Additional work is being performed to develop the correlations required to describe the hydrodynamics of the system. Initial testing of the model with experimental data shows promising results and highlights the importance of including end effects within the model.

  15. Artifact removal from EEG data with empirical mode decomposition

    NASA Astrophysics Data System (ADS)

    Grubov, Vadim V.; Runnova, Anastasiya E.; Efremova, Tatyana Yu.; Hramov, Alexander E.

    2017-03-01

    In the paper we propose the novel method for dealing with the physiological artifacts caused by intensive activity of facial and neck muscles and other movements in experimental human EEG recordings. The method is based on analysis of EEG signals with empirical mode decomposition (Hilbert-Huang transform). We introduce the mathematical algorithm of the method with following steps: empirical mode decomposition of EEG signal, choosing of empirical modes with artifacts, removing empirical modes with artifacts, reconstruction of the initial EEG signal. We test the method on filtration of experimental human EEG signals from movement artifacts and show high efficiency of the method.

  16. Experiment to Detect Accelerating Modes in a Photonic Bandgap Fiber

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

    England, R.J.; /SLAC; Colby, E.R.

    An experimental effort is currently underway at the E-163 test beamline at Stanford Linear Accelerator Center to use a hollow-core photonic bandgap (PBG) fiber as a high-gradient laser-based accelerating structure for electron bunches. For the initial stage of this experiment, a 50pC, 60 MeV electron beam will be coupled into the fiber core and the excited modes will be detected using a spectrograph to resolve their frequency signatures in the wakefield radiation generated by the beam. They will describe the experimental plan and recent simulation studies of candidate fibers.

  17. Responsive Environment Program Brooklyn, N.Y., Sept. 1968-June 1969: The Talking Typewriter. Final Report.

    ERIC Educational Resources Information Center

    Israel, Benjamin L.; Litwin, Zelda

    This progress report covers a 6-month period in the second year of an experimental research project to test the utility of the Edison Responsive Environment Talking Typewriter as a major tool for teaching both initial and remedial reading to educationally disadvantaged youth. Conducted in six schools in Brooklyn, New York, the study included…

  18. The Effects of Face Expertise Training on the Behavioral Performance and Brain Activity of Adults with High Functioning Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Faja, Susan; Webb, Sara Jane; Jones, Emily; Merkle, Kristen; Kamara, Dana; Bavaro, Joshua; Aylward, Elizabeth; Dawson, Geraldine

    2012-01-01

    The effect of expertise training with faces was studied in adults with ASD who showed initial impairment in face recognition. Participants were randomly assigned to a computerized training program involving either faces or houses. Pre- and post-testing included standardized and experimental measures of behavior and event-related brain potentials…

  19. Reading Achievement in Relation to Phonological Coding and Awareness in Deaf Readers: A Meta-Analysis

    ERIC Educational Resources Information Center

    Mayberry, Rachel I.; del Giudice, Alex A.; Lieberman, Amy M.

    2011-01-01

    The relation between reading ability and phonological coding and awareness (PCA) skills in individuals who are severely and profoundly deaf was investigated with a meta-analysis. From an initial set of 230 relevant publications, 57 studies were analyzed that experimentally tested PCA skills in 2,078 deaf participants. Half of the studies found…

  20. The influence of cutting speed and cutting initiation location in specimen preparation for the microtensile bond strength test.

    PubMed

    Abreu, Celina Wanderley; Santosb, Jarbas F; Passos, Sheila Pestana; Michida, Silvia Masae; Takahashi, Fernando Eidi; Bottino, Marco Antonio

    2011-06-01

    This study evaluated the effect of cutting initiation location and cutting speed on the bond strength between resin cement and feldspathic ceramic. Thirty-six blocks (6.4 x 6.4 x 4.8 mm) of ceramic (Vita VM7) were produced. The ceramic surfaces were etched with 10% hydrofluoric acid gel for 60 s and then silanized. Each ceramic block was placed in a silicon mold with the treated surface exposed. A resin cement (Variolink II) was injected into the mold over the treated surface and polymerized. The resin cement-ceramic blocks were divided into two groups according to experimental conditions: a) cutting initiation location - resin cement, ceramic and interface; and b) cutting speed - 10,000, 15,000, and 20,000 rpm. The specimens were sectioned to achieve non-trimmed bar specimens. The microtensile test was performed in a universal testing machine (1 mm/min). The failure modes were examined using an optical light microscope and SEM. Bond strength results were analyzed using one-way ANOVA and Tukey's test (α = 0.05). Significant influences of cutting speed and initiation location on bond strength (p < 0.05) were observed. The highest mean was achieved for specimens cut at 15,000 rpm at the interface (15.12 ± 5.36 MPa). The lowest means were obtained for specimens cut at the highest cutting speed in resin cement (8.50 ± 3.27 MPa), and cut at the lowest cutting speed in ceramic (8.60 ± 2.65 MPa). All groups showed mainly mixed failure (75% to 100%). The cutting speed and initiation location are important factors that should be considered during specimen preparation for microtensile bond strength testing, as both may influence the bond strength results.

  1. Numerical Investigation of Fracture Propagation in Geomaterials

    NASA Astrophysics Data System (ADS)

    Newell, P.; Borowski, E.; Major, J. R.; Eichhubl, P.

    2015-12-01

    Fracture in geomaterials is a critical behavior that affects the long-term structural response of geosystems. The processes involving fracture initiation and growth in rocks often span broad time scales and size scales, contributing to the complexity of these problems. To better understand fracture behavior, the authors propose an initial investigation comparing the fracture testing techniques of notched three-point bending (N3PB), short rod (SR), and double torsion (DT) on geomaterials using computational analysis. Linear softening cohesive fracture modeling (LCFM) was applied using ABAQUS to computationally simulate the three experimental set-ups. By applying material properties obtained experimentally, these simulations are intended to predict single-trace fracture growth. The advantages and limitations of the three testing techniques were considered for application to subcritical fracture propagation taking into account the accuracy of constraints, load applications, and modes of fracture. This work is supported as part of the Geomechanics of CO2 Reservoir Seals, a DOE-NETL funded under Award Number DE-FOA-0001037. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  2. Numerical and experimental investigation of the bending response of thin-walled composite cylinders

    NASA Technical Reports Server (NTRS)

    Fuchs, J. P.; Hyer, M. W.; Starnes, J. H., Jr.

    1993-01-01

    A numerical and experimental investigation of the bending behavior of six eight-ply graphite-epoxy circular cylinders is presented. Bending is induced by applying a known end-rotation to each end of the cylinders, analogous to a beam in bending. The cylinders have a nominal radius of 6 inches, a length-to-radius ratio of 2 and 5, and a radius-to-thickness ratio of approximately 160. A (+/- 45/0/90)S quasi-isotropic layup and two orthotropic layups, (+/- 45/0 sub 2)S and (+/- 45/90 sub 2)S, are studied. A geometrically nonlinear special-purpose analysis, based on Donnell's nonlinear shell equations, is developed to study the prebuckling responses and gain insight into the effects of non-ideal boundary conditions and initial geometric imperfections. A geometrically nonlinear finite element analysis is utilized to compare with the prebuckling solutions of the special-purpose analysis and to study the buckling and post buckling responses of both geometrically perfect and imperfect cylinders. The imperfect cylinder geometries are represented by an analytical approximation of the measured shape imperfections. Extensive experimental data are obtained from quasi-static tests of the cylinders using a test fixture specifically designed for the present investigation. A description of the test fixture is included. The experimental data are compared to predictions for both perfect and imperfect cylinder geometries. Prebuckling results are presented in the form of displacement and strain profiles. Buckling end-rotations, moments, and strains are reported, and predicted mode shapes are presented. Observed and predicted moment vs. end-rotation relations, deflection patterns, and strain profiles are illustrated for the post buckling responses. It is found that a geometrically nonlinear boundary layer behavior characterizes the prebuckling responses. The boundary layer behavior is sensitive to laminate orthotropy, cylinder geometry, initial geometric imperfections, applied end-rotation, and non-ideal boundary conditions. Buckling end-rotations, strains, and moments are influenced by laminate orthotropy and initial geometric imperfections. Measured buckling results correlate well with predictions for the geometrically imperfect specimens. The postbuckling analyses predict equilibrium paths with a number of scallop-shaped branches that correspond to unique deflection patterns. The observed postbuckling deflection patterns and measured strain profiles show striking similarities to the predictions in some cases. Ultimate failure of the cylinders is attributed to an interlaminar shear failure mode along the nodal lines of the postbuckling deflection patterns.

  3. Experimental study of the penetrating of plates by projectile at low initial speeds

    NASA Astrophysics Data System (ADS)

    Orlov, M. Yu; Orlova, Yu N.; Smakotin, Ig L.; Glazyrin, V. P.; Orlov, Yu N.

    2017-11-01

    The research of the penetration process of lightweight plates by a projectile in the range of initial velocities up to 325 m/s was attempted. The projectile was a shell bullet and the barriers were of ice, MDF-panels and plexiglas barriers. The response of barriers to impact loading is studied. High-speed shooting of each experiment is obtained, including photos of the front and rear sides of the barriers. An attempt was made to reproduce the scenario of the destruction of barriers. The results of experiments can be interpreted only as qualitative tests. Projectile was not destroyed.

  4. Comparison of Analytical Predictions and Experimental Results for a Dual Brayton Power System (Discussion on Test Hardware and Computer Model for a Dual Brayton System)

    NASA Technical Reports Server (NTRS)

    Johnson, Paul K.

    2007-01-01

    NASA Glenn Research Center (GRC) contracted Barber-Nichols, Arvada, CO to construct a dual Brayton power conversion system for use as a hardware proof of concept and to validate results from a computational code known as the Closed Cycle System Simulation (CCSS). Initial checkout tests were performed at Barber- Nichols to ready the system for delivery to GRC. This presentation describes the system hardware components and lists the types of checkout tests performed along with a couple issues encountered while conducting the tests. A description of the CCSS model is also presented. The checkout tests did not focus on generating data, therefore, no test data or model analyses are presented.

  5. Heavy-section steel irradiation program. Progress report, April 1996--September 1996

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

    Corwin, W.R.

    1997-09-01

    The Heavy-Section Steel Irradiation Program was established to quantitatively assess the effects of neutron irradiation on the material behavior of typical reactor pressure vessel (RPV) steels. During this period, fracture mechanics testing of specimens of the irradiated low upper shelf (LUS) weld were completed and analyses performed. Heat treatment of five RPV plate materials was initiated to examine phosphorus segregation effects on the fracture toughness of the heat affected zone of welds. Initial results show that all five materials exhibited very large prior austenite grain sizes as a consequence of the initial heat treatment. Irradiated and annealed specimens of LUSmore » weld material were tested and analyzed. Four sets of Charpy V-notch (CVN) specimens were aged at various temperatures and tested to examine the reason for overrecovery of upper shelf energy that has been observed. Molecular dynamics cascade simulations were extended to 40 keV and have provided information representative of most of the fast neutron spectrum. Investigations of the correlation between microstructural changes and hardness changes in irradiated model alloys was also completed. Preliminary planning for test specimen machining for the Japan Power Development Reactor was completed. A database of Charpy impact and fracture toughness data for RPV materials that have been tested in the unirradiated and irradiated conditions is being assembled and analyzed. Weld metal appears to have similar CVN and fracture toughness transition temperature shifts, whereas the fracture toughness shifts are greater than CVN shifts for base metals. Draft subcontractor reports on precracked cylindrical tensile specimens were completed, reviewed, and are being revised. Testing on precracked CVN specimens, both quasi-static and dynamic, was evaluated. Additionally, testing of compact specimens was initiated as an experimental comparison of constraint limitations. 16 figs., 2 tabs.« less

  6. Ground based interferometric radar initial look at Longview, Blue Springs, Tuttle Creek, and Milford Dams

    NASA Astrophysics Data System (ADS)

    Deng, Huazeng

    Measuring millimeter and smaller deformation has been demonstrated in the literature using RADAR. To address in part the limitations in current commercial satellite-based SAR datasets, a University of Missouri (MU) team worked with GAMMA Remote Sensing to develop a specialized (dual-frequency, polarimetric, and interferometric) ground-based real-aperture RADAR (GBIR) instrument. The GBIR device is portable with its tripod system and control electronics. It can be deployed to obtain data with high spatial resolution (i.e. on the order of 1 meter) and high temporal resolution (i.e. on the order 1 minute). The high temporal resolution is well suited for measurements of rapid deformation. From the same geodetic position, the GBIR may collect dual frequency data set using C-band and Ku-band. The overall goal of this project is to measure the deformation from various scenarios by applying the GBIR system. Initial efforts have been focusing on testing the system performance on different types of targets. This thesis details a number of my efforts on experimental and processing activities at the start of the MU GBIR imaging project. For improved close range capability, a wideband dual polarized antenna option was produced and tested. For GBIR calibration, several trihedral corner reflectors were designed and fabricated. In addition to experimental activities and site selection, I participated in advanced data processing activities. I processed GBIR data in several ways including single-look-complex (SLC) image generation, imagery registration, and interferometric processing. A number of initial-processed GBIR image products are presented from four dams: Longview, Blue Springs, Tuttle Creek, and Milford. Excellent imaging performance of the MU GBIR has been observed for various target types such as riprap, concrete, soil, rock, metal, and vegetation. Strong coherence of the test scene has been observed in the initial interferograms.

  7. Ignition-and-Growth Modeling of NASA Standard Detonator and a Linear Shaped Charge

    NASA Technical Reports Server (NTRS)

    Oguz, Sirri

    2010-01-01

    The main objective of this study is to quantitatively investigate the ignition and shock sensitivity of NASA Standard Detonator (NSD) and the shock wave propagation of a linear shaped charge (LSC) after being shocked by NSD flyer plate. This combined explosive train was modeled as a coupled Arbitrary Lagrangian-Eulerian (ALE) model with LS-DYNA hydro code. An ignition-and-growth (I&G) reactive model based on unreacted and reacted Jones-Wilkins-Lee (JWL) equations of state was used to simulate the shock initiation. Various NSD-to-LSC stand-off distances were analyzed to calculate the shock initiation (or failure to initiate) and detonation wave propagation along the shaped charge. Simulation results were verified by experimental data which included VISAR tests for NSD flyer plate velocity measurement and an aluminum target severance test for LSC performance verification. Parameters used for the analysis were obtained from various published data or by using CHEETAH thermo-chemical code.

  8. [Experimental-morphologic study of bone tissue reaction to carbon-containing material implantation with initiated X-ray contrast property].

    PubMed

    Grigorian, A S; Nabiev, F Kh; Golovin, R V

    2005-01-01

    In experimental study on 15 rabbits (chinchilla) influence of titanium plates implanted lapped on adjacent tissues in the region of the lower jaw body (comparison group) and carbon material with added boron in the concentrations of 8 and 15% (the study group) was studied. Results of the experimental-morphological investigation show that carbon-based materials with boron addition (with its content 8 and 15%) did not impede adaptive rebuilding of bone tissues and in particular bone structure regeneration in the process of reactive rebuilding of the "maternal" bone. Moreover, as the result of reactive processes developing in osseous tissues after implantation of the tested materials their successful integration in surrounding tissue structures was detected.

  9. Laboratory test methods for combustion stability properties of solid propellants

    NASA Technical Reports Server (NTRS)

    Strand, L. D.; Brown, R. S.

    1992-01-01

    An overview is presented of experimental methods for determining the combustion-stability properties of solid propellants. The methods are generally based on either the temporal response to an initial disturbance or on external methods for generating the required oscillations. The size distribution of condensed-phase combustion products are characterized by means of the experimental approaches. The 'T-burner' approach is shown to assist in the derivation of pressure-coupled driving contributions and particle damping in solid-propellant rocket motors. Other techniques examined include the rotating-valve apparatus, the impedance tube, the modulated throat-acoustic damping burner, and the magnetic flowmeter. The paper shows that experimental methods do not exist for measuring the interactions between acoustic velocity oscillations and burning propellant.

  10. Experimental and Modeling Studies of Crush, Puncture, and Perforation Scenarios in the Steven Impact Test

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

    Vandersall, K S; Chidester, S K; Forbes, J W

    2002-06-28

    The Steven test and associated modeling has greatly increased the fundamental knowledge of practical predictions of impact safety hazards for confined and unconfined explosive charges. Building on a database of initial work, experimental and modeling studies of crush, puncture, and perforation scenarios were investigated using the Steven impact test. The descriptions of crush, puncture, and perforation arose from safety scenarios represented by projectile designs that ''crush'' the energetic material or either ''puncture'' with a pinpoint nose or ''perforate'' the front cover with a transportation hook. As desired, these scenarios offer different aspects of the known mechanisms that control ignition: friction,more » shear and strain. Studies of aged and previously damaged HMX-based high explosives included the use of embedded carbon foil and carbon resistor gauges, high-speed cameras, and blast wave gauges to determine the pressure histories, time required for an explosive reaction, and the relative violence of those reactions, respectively. Various ignition processes were modeled as the initial reaction rate expression in the Ignition and Growth reaction rate equations. Good agreement with measured threshold velocities, pressure histories, and times to reaction was calculated for LX-04 impacted by several projectile geometries using a compression dependent ignition term and an elastic-plastic model with a reasonable yield strength for impact strain rates.« less

  11. Highlights from a Mach 4 Experimental Demonstration of Inlet Mode Transition for Turbine-Based Combined Cycle Hypersonic Propulsion

    NASA Technical Reports Server (NTRS)

    Foster, Lancert E.; Saunders, John D., Jr.; Sanders, Bobby W.; Weir, Lois J.

    2012-01-01

    NASA is focused on technologies for combined cycle, air-breathing propulsion systems to enable reusable launch systems for access to space. Turbine Based Combined Cycle (TBCC) propulsion systems offer specific impulse (Isp) improvements over rocket-based propulsion systems in the subsonic takeoff and return mission segments along with improved safety. Among the most critical TBCC enabling technologies are: 1) mode transition from the low speed propulsion system to the high speed propulsion system, 2) high Mach turbine engine development and 3) innovative turbine based combined cycle integration. To address these challenges, NASA initiated an experimental mode transition task including analytical methods to assess the state-of-the-art of propulsion system performance and design codes. One effort has been the Combined-Cycle Engine Large Scale Inlet Mode Transition Experiment (CCE-LIMX) which is a fully integrated TBCC propulsion system with flowpath sizing consistent with previous NASA and DoD proposed Hypersonic experimental flight test plans. This experiment was tested in the NASA GRC 10 by 10-Foot Supersonic Wind Tunnel (SWT) Facility. The goal of this activity is to address key hypersonic combined-cycle engine issues including: (1) dual integrated inlet operability and performance issues-unstart constraints, distortion constraints, bleed requirements, and controls, (2) mode-transition sequence elements caused by switching between the turbine and the ramjet/scramjet flowpaths (imposed variable geometry requirements), and (3) turbine engine transients (and associated time scales) during transition. Testing of the initial inlet and dynamic characterization phases were completed and smooth mode transition was demonstrated. A database focused on a Mach 4 transition speed with limited off-design elements was developed and will serve to guide future TBCC system studies and to validate higher level analyses.

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

    Nabeel A. Riza

    The goals of the second six months of the Phase 2 of this project were to conduct first time experimental studies using optical designs and some initial hardware developed in the first 6 months of Phase 2. One focus is to modify the SiC chip optical properties to enable gas species sensing with a specific gas species under high temperature and pressure. The goal was to acquire sensing test data using two example inert and safe gases and show gas discrimination abilities. A high pressure gas mixing chamber was to be designed and assembled to achieve the mentioned gas sensingmore » needs. Another goal was to initiate high temperature probe design by developing and testing a probe design that leads to accurately measuring the thickness of the deployed SiC sensor chip to enable accurate overall sensor system design. The third goal of this phase of the project was to test the SiC chip under high pressure conditions using the earlier designed calibration cell to enable it to act as a pressure sensor when doing gas detection. In this case, experiments using a controlled pressure system were to deliver repeatable pressure measurement data. All these goals have been achieved and are described in detail in the report. Both design process and diagrams for the mechanical elements as well as the optical systems are provided. Photographs or schematics of the fabricated hardware are provided. Experimental data from the three optical sensor systems (i.e., Thickness, pressure, and gas species) is provided. The design and experimentation results are summarized to give positive conclusions on the proposed novel high temperature high pressure gas species detection optical sensor technology.« less

  13. Compression of laminated composite beams with initial damage

    NASA Technical Reports Server (NTRS)

    Breivik, Nicole L.; Gurdal, Zafer; Griffin, O. H., Jr.

    1993-01-01

    The effect of isolated damage modes on the compressive strength and failure characteristics of laminated composite test specimens were evaluated experimentally and numerically. In addition to specimens without initial damage, specimens with three types of initial damage were considered: (1) specimens with short delaminations distributed evenly through the specimen thickness, (2) specimens with few long delaminations, and (3) specimens with local fiber damage in the surface plies under the three-point bend contact point. It was found that specimens with short multiple delamination experienced the greatest reduction in compression strength compared to the undamaged specimens. Single delaminations far from the specimen surface had little effect on the final compression strength, and moderate strength reduction was observed for specimens with localized surface ply damage.

  14. Experiences from First Top-Off Injection at the Stanford Synchrotron Radiation Lightsource

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

    Bauer, J.M.; Liu, J.C.; Prinz, A.

    2009-12-11

    As the Stanford Synchrotron Radiation Lightsource (SSRL) of the SLAC National Accelerator Laboratory (SLAC) is moving toward Top-Off injection mode, SLAC's Radiation Protection Department is working with SSRL on minimizing the radiological hazards of this mode. One such hazard is radiation that is created inside the accelerator concrete enclosure by injected beam. Since during Top-Off injection the stoppers that would otherwise isolate the storage ring from the experimental area stay open, the stoppers no longer prevent such radiation from reaching the experimental area. The level of this stray radiation was measured in April 2008 during the first Top-Off injection tests.more » They revealed radiation dose rates of up to 18 microSv/h (1.8 millirem/h) outside the experimental hutches, significantly higher than our goal of 1 microSv/h (0.1 millirem/h). Non-optimal injection increased the measured dose rates by a factor two. Further tests in 2008 indicated that subsequent improvements by SSRL to the injection system have reduced the dose rates to acceptable levels. This presentation describes the studies performed before the Top-Off tests, the tests themselves and their major results (both under initial conditions and after improvements were implemented), and presents the controls being implemented for full and routine Top-Off injection.« less

  15. Experimental Study on Surrogate Nuclear Fuel Rods under Reversed Cyclic Bending

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

    Wang, Hong; Wang, Jy-An John

    The mechanical behavior of spent nuclear fuel (SNF) rods under reversed cyclic bending or bending fatigue must be understood to evaluate their vibration integrity in a transportation environment. This is especially important for high-burnup fuels (>45 GWd/MTU), which have the potential for increased structural damage. It has been demonstrated that the bending fatigue of SNF rods can be effectively studied using surrogate rods. In this investigation, surrogate rods made of stainless steel (SS) 304 cladding and aluminum oxide pellets were tested under load or moment control at a variety of amplitude levels at 5 Hz using the Cyclic Integrated Reversible-Bendingmore » Fatigue Tester developed at Oak Ridge National Laboratory. The behavior of the rods was further characterized using flexural rigidity and hysteresis data, and fractography was performed on the failed rods. The proposed surrogate rods captured many of the characteristics of deformation and failure mode observed in SNF, including the linear-to-nonlinear deformation transition and large residual curvature in static tests, PPI and PCMI failure mechanisms, and large variation in the initial structural condition. Rod degradation was measured and characterized by measuring the flexural rigidity; the degradation of the rigidity depended on both the moment amplitude applied and the initial structural condition of the rods. It was also shown that a cracking initiation site can be located on the internal surface or the external surface of cladding. Finally, fatigue damage to the bending rods can be described in terms of flexural rigidity, and the fatigue life of rods can be predicted once damage model parameters are properly evaluated. The developed experimental approach, test protocol, and analysis method can be used to study the vibration integrity of SNF rods in the future.« less

  16. Measurement of fracture properties of concrete at high strain rates

    PubMed Central

    Cendón, D. A.; Sánchez-Gálvez, V.; Gálvez, F.

    2017-01-01

    An analysis of the spalling technique of concrete bars using the modified Hopkinson bar was carried out. A new experimental configuration is proposed adding some variations to previous works. An increased length for concrete specimens was chosen and finite-element analysis was used for designing a conic projectile to obtain a suitable triangular impulse wave. The aim of this initial work is to establish an experimental framework which allows a simple and direct analysis of concrete subjected to high strain rates. The efforts and configuration of these primary tests, as well as the selected geometry and dimensions for the different elements, have been focused to achieve a simple way of identifying the fracture position and so the tensile strength of tested specimens. This dynamic tensile strength can be easily compared with previous values published in literature giving an idea of the accuracy of the method and technique proposed and the possibility to extend it in a near future to obtain other mechanical properties such as the fracture energy. The tests were instrumented with strain gauges, accelerometers and high-speed camera in order to validate the results by different ways. Results of the dynamic tensile strength of the tested concrete are presented. This article is part of the themed issue ‘Experimental testing and modelling of brittle materials at high strain rates’. PMID:27956510

  17. Final construction and testing of an experimental sprinkler/groundwater treatment system for proposed use by the village of Utica, Nebraska.

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

    NONE

    2005-06-17

    The testing described above demonstrates that the experimental sprinkler designed by Argonne could be successfully, and safely, used by the Village of Utica for irrigation of the town's playing fields, using contaminated (by carbon tetrachloride) groundwater from the shallow aquifer beneath the town. Routine operation of the sprinkler within the range of parameters identified by the testing program would effectively reduce carbon tetrachloride concentrations in the discharged spray reaching the ground to levels below the MCL (5 {micro}g/l). CCC/USDA and Argonne propose to test use of the experimental sprinkler by the Village of Utica during the next (Summer 2001) growingmore » season, under Argonne supervision. Water will be supplied from the well to the sprinkler drive unit using a temporary, flexible (high-pressure hose) connection. Argonne will provide training to Village staff in the setup and use of the sprinkler, and will conduct periodic monitoring (proposed biweekly, initially) of the watering operations and sampling and analysis of the spray discharge from the unit, to ensure that the specified groundwater cleanup performance of the sprinkler system (to carbon tetrachloride values <5 {micro}g/L) is maintained. If testing of the sprinkler in this manner proves successful during 2001, CCC/USDA will seek to permanently transfer ownership and operation responsibilities for the sprinkler to the Utica Village Board.« less

  18. How to decrease pedestrian injuries: conceptual evolutions starting from 137 crash tests.

    PubMed

    Thollon, Lionel; Jammes, Christian; Behr, Michel; Arnoux, Pierre-Jean; Cavallero, Claude; Brunet, Christian

    2007-02-01

    The improvement of vulnerable users' protection has become an essential objective for our society. Injury assessments observed in clinical traumatology have led researchers and manufacturers to understand the mechanisms involved and to design safe vehicles (to reduce the severity of pedestrian injuries). In all, 137 crash tests between 1979 and 2004 with postmortal human subjects (PMHS) were performed at the Laboratory of Applied Biomechanics to access pedestrian protection. A retrospective analysis of these experimental tests, pedestrian/car impacts (full scale or subsystems), performed at the laboratory is thus proposed. This document focuses on injury mechanisms investigation on the evolution of the experimental approach, as well as on the vehicles' technological improvements performed by car manufacturers. The analysis of experimental results (injury assessment, kinematics, vehicle deformations, etc.) shows the complexity and variety of injury mechanisms. The injury assessment shows the need to improve lower-limb joints protection, as well as head and spine segments, because of the difficulties of surgical repair of these injuries. Experimental tests contribute to evaluate the automobile safety evolution in the field of pedestrian protection. The main induced car improvements concern considerable efforts on vehicle material behavior and their capacity to dissipate energy during shocks (replacement of the convex rigid bumpers by deformable structures, modification of the windscreen structure). They also concern the suppression of all aggressive structures for the pedestrian (spare wheel initially placed on the front part of the vehicle, protection of the heels of windscreen wiper, etc.).

  19. Influence of Small Change of Porosity on Shock Initiation of an HMX/TATB/Viton Explosive and Ignition and Growth Modeling

    NASA Astrophysics Data System (ADS)

    Liu, Yan; Hussain, Tariq; Huang, Fenglei; Duan, Zhuoping

    2016-07-01

    All solid explosives in practical use are more or less porous. Although it is known that the change in porosity affects the shock sensitivity of solid explosives, the effect of small changes in porosity on the sensitivity needs to be determined for safe and efficient use of explosive materials. In this study, the influence of a small change in porosity on shock initiation and the subsequent detonation growth process of a plastic-bonded explosive PBXC03, composed of 87% cyclotetramethylene-tetranitramine (HMX), 7% triaminotrinitrobenzene (TATB), and 6% Viton by weight, are investigated by shock to detonation transition experiments. Two explosive formulations of PBXC03 having the same initial grain sizes pressed to 98 and 99% of theoretical mass density (1.873 g/cm3) respectively are tested using the in situ manganin piezoresistive pressure gauge technique. Numerical modeling of the experiments is performed using an ignition and growth reactive flow model. Reasonable agreement with the experimental results is obtained by increasing the growth term coefficient in the Lee-Tarver ignition and growth model with porosity. Combining the experimental and simulation results shows that the shock sensitivity increases with porosity for PBXC03 having the same explosive initial grain sizes for the pressures (about 3.1 GPa) applied in the experiments.

  20. Use of phase change materials during compressed air expansion for isothermal CAES plants

    NASA Astrophysics Data System (ADS)

    Castellani, B.; Presciutti, A.; Morini, E.; Filipponi, M.; Nicolini, A.; Rossi, F.

    2017-11-01

    Compressed air energy storage (CAES) plants are designed to store compressed air into a vessel or in an underground cavern and to expand it in an expansion turbine when energy demand is high. An innovative CAES configuration recently proposed is the isothermal process. Several methods to implement isothermal CAES configuration are under investigation. In this framework, the present paper deals with the experimental testing of phase change materials (PCM) during compressed air expansion phase. The experimental investigation was carried out by means of an apparatus constituted by a compression section, a steel pressure vessel, to which an expansion valve is connected. The initial internal absolute pressure was equal to 5 bar to avoid moisture condensation and the experimental tests were carried out with two paraffin-based PCM amounts (0.05 kg and 0.1 kg). Results show that the temperature change during air expansion decreases with increasing the PCM amount inside the vessel. With the use of PCM during expansions an increase of the expansion work occurs. The increase is included in the range from 9.3% to 18.2%. In every test there is an approach to the isothermal values, which represent the maximum theoretical value of the obtainable expansion work.

  1. Investigation of critical burning of fuel droplets

    NASA Technical Reports Server (NTRS)

    Allison, C. B.; Canada, G. S.; Faeth, G. M.

    1972-01-01

    Measurements were made on the burning of liquid hydrazine, MMH, and UDMH in a combustion gas environment. The experimental range of these tests involved gas temperatures of 1660-2530 K, oxygen concentrations of 0-42% by mass and droplet diameters (employing both droplets and porous spheres) of 0.11-1.91 cm. at atmospheric pressure. A simplified hybrid combustion theory was developed which was found to correlate the present results as well as the experimental measurements of other investigators. Measurements were also made of the monopropellant strand burning rates and liquid surface temperatures of a number of nitrate ester fuels and hydrazine at elevated pressures. The temperature measurements for the nitrate esters were found to be in good agreement with a theoretical model which allowed for gas solubility in the liquid phase at high pressures. Experimental results were also obtained on the burning rates and liquid surface temperatures of a number of paraffin and alcohol fuels burning in air pressures up to 72 atm. For these tests, the fuels were burned from porous spheres in a natural convection environment. Initial findings on a pressurized flat flame burner are also described as well as the design of an oscillatory combustion apparatus to test the response of burning liquid fuels.

  2. MIDURA (Minefield Detection Using Reconnaissance Assets) 1982-1983 Experimental Test Plan.

    DTIC Science & Technology

    1982-04-01

    3.2.4.2 Subjection Validation at the Salem ONG 27 3.2.4.3 Objective Validity at Fort Huachuca 28 4. TEST FLIGHTS AT ARRAYS IIa, lib, Ilia AND IIIb...subjective validation at the Salem ONG; (3) objective validation at Fort Huachuca. 3.2.4.1 Subjective Image Interpretation at ERIM The initial phase...The ERIM II’s will provide for each image estimate of PD’ Pc and PFA on a 0.00 to 1.00 scale. P is defined as the subjective probability estimate that

  3. Experimental program to determine long term characteristics of the MDE pressure transducers

    NASA Technical Reports Server (NTRS)

    Parker, C. D.

    1973-01-01

    The pressure cell sensors developed for the Pioneer 10/G meteoroid detection experiments (MDE) were investigated to enhance their application and their potential as a sensor in other MDE applications. Their Paschen characteristics were also investigated, and the effects of variations in geometry, Ni-63 platings (for initial ionizations) and sealing pressures were determined. The effects of extensive pre-flight testing and proton and heavy ion space radiation were investigated. Flight-quality pressure panels/cells were committed to long term testing to demonstrate their suitability for the Pioneer 10/G Missions.

  4. Influence of humidity on the initial emittable concentration of formaldehyde and hexaldehyde in building materials: experimental observation and correlation

    PubMed Central

    Huang, Shaodan; Xiong, Jianyin; Cai, Chaorui; Xu, Wei; Zhang, Yinping

    2016-01-01

    Humidity is one of the main environmental factors affecting the emission rate and key parameters of formaldehyde and volatile organic compounds (VOCs) from building materials. Meanwhile, the initial emittable concentration (Cm,0) is proved to be the most sensitive key parameter to the emission behaviours. However, there is no report on the relationship between humidity and Cm,0. In this paper, Cm,0 of formaldehyde and hexaldehyde from a type of medium density fiberboard in absolute humidity (AH) range of 4.6–19.6 g/m3 at 25 °C were tested by virtue of a C-history method. Experimental results indicate that Cm,0 is dramatically dependent on AH, increased by 10 and 2 times for formaldehyde and hexaldehyde when AH rising from 4.6 g/m3 to 19.6 g/m3. A linear relationship between the logarithm of Cm,0 and AH is obtained based on the measured results. In addition, a correlation characterizing the association of emission rate and AH is derived. The effectiveness of the correlation is verified with our experimental results as well as data from literature. With the correlations, the Cm,0 or emission rate different from the test AH conditions can be conveniently obtained. This study should be useful for predicting the emission characteristics of humidity changing scenarios and for source control. PMID:27025353

  5. The use of experimental data in an MTR-type nuclear reactor safety analysis

    NASA Astrophysics Data System (ADS)

    Day, Simon E.

    Reactivity initiated accidents (RIAs) are a category of events required for research reactor safety analysis. A subset of this is unprotected RIAs in which mechanical systems or human intervention are not credited in the response of the system. Light-water cooled and moderated MTR-type ( i.e., aluminum-clad uranium plate fuel) reactors are self-limiting up to some reactivity insertion limit beyond which fuel damage occurs. This characteristic was studied in the Borax and Spert reactor tests of the 1950s and 1960s in the USA. This thesis considers the use of this experimental data in generic MTR-type reactor safety analysis. The approach presented herein is based on fundamental phenomenological understanding and uses correlations in the reactor test data with suitable account taken for differences in important system parameters. Specifically, a semi-empirical approach is used to quantify the relationship between the power, energy and temperature rise response of the system as well as parametric dependencies on void coefficient and the degree of subcooling. Secondary effects including the dependence on coolant flow are also examined. A rigorous curve fitting approach and error assessment is used to quantify the trends in the experimental data. In addition to the initial power burst stage of an unprotected transient, the longer term stability of the system is considered with a stylized treatment of characteristic power/temperature oscillations (chugging). A bridge from the HEU-based experimental data to the LEU fuel cycle is assessed and outlined based on existing simulation results presented in the literature. A cell-model based parametric study is included. The results are used to construct a practical safety analysis methodology for determining reactivity insertion safety limits for a light-water moderated and cooled MTR-type core.

  6. A Measurement Plane for Optical Networks to Manage Emergency Events

    NASA Astrophysics Data System (ADS)

    Tego, E.; Carciofi, C.; Grazioso, P.; Petrini, V.; Pompei, S.; Matera, F.; Attanasio, V.; Nastri, E.; Restuccia, E.

    2017-11-01

    In this work, we show a wide geographical area optical network test bed, adopting the mPlane measurement plane for monitoring its performance and to manage software defined network approaches, with some specific tests and procedures dedicated to respond to disaster events and to support emergency networks. Such a test bed includes FTTX accesses, and it is currently implemented to support future 5G wireless services with slicing procedures based on Carrier Ethernet. The characteristics of this platform have been experimentally tested in the case of a damage-causing link failure and traffic congestion, showing a fast reactions to these disastrous events, allowing the user to recharge the initial QoS parameters.

  7. 7075-T6 and 2024-T351 Aluminum Alloy Fatigue Crack Growth Rate Data

    NASA Technical Reports Server (NTRS)

    Forth, Scott C.; Wright, Christopher W.; Johnston, William M., Jr.

    2005-01-01

    Experimental test procedures for the development of fatigue crack growth rate data has been standardized by the American Society for Testing and Materials. Over the past 30 years several gradual changes have been made to the standard without rigorous assessment of the affect these changes have on the precision or variability of the data generated. Therefore, the ASTM committee on fatigue crack growth has initiated an international round robin test program to assess the precision and variability of test results generated using the standard E647-00. Crack growth rate data presented in this report, in support of the ASTM roundrobin, shows excellent precision and repeatability.

  8. When to start paediatric testing of the adult HIV cure research agenda?

    PubMed

    Shah, Seema K

    2017-02-01

    Ethical guidelines recommend that experimental interventions should be tested in adults first before they are tested and approved in children. Some challenge this paradigm, however, and recommend initiating paediatric testing after preliminary safety testing in adults in certain cases. For instance, commentators have argued for accelerated testing of HIV vaccines in children. Additionally, HIV cure research on the use of very early therapy (VET) in infants, prompted in part by the Mississippi baby case, is one example of a strategy that is currently being tested in infants before it has been well tested in adults. Because infants' immune systems are still developing, the timing of HIV transmission is easier to identify in infants than in adults, and infants who receive VET might never develop the viral reservoirs that make HIV so difficult to eradicate, infants may be uniquely situated to achieve HIV cure or sustained viral remission. Several commentators have now argued for earlier initiation of HIV cure interventions other than (or in addition to) VET in children. HIV cure research is therefore a good case for re-examining the important question of when to initiate paediatric research. I will argue that, despite the potential for HIV cure research to benefit children and the scientific value of involving children in this research, the HIV cure agenda should not accelerate the involvement of children for the following reasons: HIV cure research is highly speculative, risky, aimed at combination approaches and does not compare favourably with the available alternatives. I conclude by drawing general implications for the initiation of paediatric testing, including that interventions that have to be used in combination with others and cures for chronic diseases may not be valuable enough to justify early paediatric testing. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  9. Neuron recycling for learning the alphabetic principles.

    PubMed

    Scliar-Cabral, Leonor

    2014-01-01

    The main purpose of this paper is to discuss an approach to the phonic method of learning-teaching early literacy development, namely that the visual neurons must be recycled to recognize the small differences among pertinent letter features. In addition to the challenge of segmenting the speech chain and the syllable for learning the alphabetic principles, neuroscience has demonstrated another major challenge: neurons in mammals are programmed to process visual signals symmetrically. In order to develop early literacy, visual neurons must be recycled to overcome this initial programming together with phonological awareness, expanding it with the ability to delimit words, including clitics, as well as assigning stress to words. To achieve this goal, Scliar's Early Literacy Development System was proposed and tested. Sixteen subjects (10 girls and 6 boys) comprised the experimental group (mean age 6.02 years), and 16 subjects (7 girls and 9 boys) formed the control group (mean age 6.10 years). The research instruments were a psychosociolinguistic questionnaire to reveal the subjects' profile and a post-test battery of tests. At the beginning of the experiment, the experimental group was submitted to an intervention program based on Scliar's Early Literacy Development System. One of the tests is discussed in this paper, the grapheme-phoneme test: subjects had to read aloud a pseudoword with 4 graphemes, signaled by the experimenter and designed to assess the subject's ability to convert a grapheme into its correspondent phoneme. The average value for the test group was 25.0 correct answers (SD = 11.4); the control group had an average of 14.3 correct answers (SD = 10.6): The difference was significant. The experimental results validate Scliar's Early Literacy Development System and indicate the need to redesign early literacy development methods. © 2014 S. Karger AG, Basel.

  10. Advanced Gas Turbine (AGT) technology report

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Engine testing, ceramic component fabrication and evaluation, component performance rig testing, and producibility experiments at Pontiac comprised AGT 100 activities of this period, January to December 1984. Two experimental engines were available and allowed the evaluation of eight experimental assemblies. Operating time accumulated was 115 hr of burning and 156 hr total. Total cumulative engine operating time is now 225 hr. Build number 11 and 12 of engine S/N 1 totaled 28 burning hours and constituted a single assembly of the engine core--the compressor, both turbines, and the gearbox. Build number 11 of engine S/N 1 included a 1:07 hr continuous test at 100% gasifier speed (86,000 rpm). Build number 8 of engine S/N 2 was the first engine test with a ceramic turbine rotor. A mechanical loss test of an engine assembly revealed the actual losses to be near the original design allowance. Component development activity included rig testing of the compressor, combustor, and regenerator. Compressor testing was initiated on a rig modified to control the transfer of heat between flow path, lubricating oil, and structure. Results show successful thermal decoupling of the rig and lubricating/cooling oil. Rig evaluation of a reduced-friction compressor was initiated. Combustor testing covered qualification of ceramic parts for engine use, mapping of operating range limits, and evaluation of a relocated igniter plug. Several seal refinements were tested on the hot regenerator rig. An alternate regenerator disk, extruded MAS, was examined and found to be currently inadequate for the AGT 100 application. Also, a new technique for measuring leakage was explored on the regenerator rig. Ceramic component activity has focused on the development of state-of-the-art material strength characteristics in full-scale hardware. Injection-molded sintered alpha-SiC rotors were produced at Carborundum in an extensive process and tool optimization study.

  11. Experimental studies of glued Aluminum-glass joints

    NASA Astrophysics Data System (ADS)

    Ligaj, B.; Wirwicki, M.; Karolewska, K.; Jasińska, A.

    2018-04-01

    Glued steel-glass or aluminum-glass joints are to be found, among other things, in vehicles (cars, buses, trains, trams) as windscreen assembly pieces for the supporting structure. For the purposes of the experiments, samples were made in which the top beam was made of the AW-2017A aluminum alloy and the bottom beam was made of thermally reinforced soda-lime glass whereas the glued joints were made of one-component polyurethane glue Körapur 175. The tests were performed under four-point bending conditions at monotonic incremental bending moment values on the Instron 5965 durability machine. The experimental study of the durability of glued joints under four-point bending conditions with the monotonic incremental bending moment allows to determine the values of stresses, whose value is related to initiation of damage of the tested joint.

  12. Initial Development and Pilot Study Design of Interactive Lecture Demonstrations for ASTRO 101

    NASA Astrophysics Data System (ADS)

    Schwortz, Andria C.; French, D. A; Gutierrez, Joseph V; Sanchez, Richard L; Slater, Timothy F.; Tatge, Coty

    2014-06-01

    Interactive lecture demonstrations (ILDs) have repeatedly shown to be effective tools for improving student achievement in the context of learning physics. As a first step toward systematic development of interactive lecture demonstrations in ASTRO 101, the introductory astronomy survey course, a systematic review of education research, describing educational computer simulations (ECSs) reveals that initial development requires a targeted study of how ASTRO 101 students respond to ECSs in the non-science majoring undergraduate lecture setting. In this project we have adopted the process by which ILDs were designed, pilot-tested, and successfully implemented in the context of physics teaching (Sokoloff & Thornton, 1997; Sokoloff & Thornton, 2004). We have designed the initial pilot-test set of ASTRO 101 ILD instructional materials relying heavily on ECSs. Both an instructor’s manual and a preliminary classroom-ready student workbook have been developed, and we are implementing a pilot study to explore their effectiveness in communicating scientific content, and the extent to which they might enhance students’ knowledge of and perception about astronomy and science in general. The study design uses a pre-/post-test quasi-experimental study design measuring students’ normalized gain scores, calculated as per Hake (1998) and Prather (2009), using a slightly modified version of S. Slater’s (2011) Test Of Astronomy STandards TOAST combined with other instruments. The results of this initial study will guide the iterative development of ASTRO 101 ILDs that are intended to both be effective at enhancing student achievement and easy for instructors to successfully implement.

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

    Lisowski, Darius D.; Kraus, Adam R.; Bucknor, Matthew D.

    A 1/2 scale test facility has been constructed at Argonne National Laboratory to study the heat removal performance and natural circulation flow patterns in a Reactor Cavity Cooling System (RCCS). Our test facility, the Natural convection Shutdown heat removal Test Facility (NSTF), supports the broader goal of developing an inherently safe and fully passive ex-vessel decay heat removal for advanced reactor designs. The project, initiated in 2010 to support the Advanced Reactor Technologies (ART), Small Modular Reactor (SMR), and Next Generation Nuclear Plant (NGNP) programs, has been conducting experimental operations since early 2014. The following paper provides a summary ofmore » some primary design features of the 26-m tall test facility along with a description of the data acquisition suite that guides our experimental practices. Specifics of the distributed fiber optic temperature measurements will be discussed, which introduces an unparalleled level of data density that has never before been implemented in a large scale natural circulation test facility. Results from our test series will then be presented, which provide insight into the thermal hydraulic behavior at steady-state and transient conditions for varying heat flux levels and exhaust chimney configuration states. (C) 2016 Elsevier B.V. All rights reserved.« less

  14. Summary and evaluation: fuel dynamics loss-of-flow experiments (tests L2, L3, and L4)

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

    Barts, E.W.; Deitrich, L.W.; Eberhart, J.G.

    1975-09-01

    Three similar experiments conducted to support the analyses of hypothetical LMFBR unprotected-loss-of-flow accidents are summarized and evaluated. The tests, designated L2, L3, and L4, provided experimental data against which accident-analysis codes could be compared, so as to guide further analysis and modeling of the initiating phases of the hypothetical accident. The tests were conducted using seven-pin bundles of mixed-oxide fuel pins in Mark-II flowing-sodium loops in the TREAT reactor. Test L2 used fresh fuel. Tests L3 and L4 used irradiated fuel pins having, respectively, ''intermediate-power'' (no central void) and ''high-power'' (fully developed central void) microstructure. 12 references. (auth)

  15. Evaluations of the conformational search accuracy of CAMDAS using experimental three-dimensional structures of protein-ligand complexes

    NASA Astrophysics Data System (ADS)

    Oda, A.; Yamaotsu, N.; Hirono, S.; Takano, Y.; Fukuyoshi, S.; Nakagaki, R.; Takahashi, O.

    2013-08-01

    CAMDAS is a conformational search program, through which high temperature molecular dynamics (MD) calculations are carried out. In this study, the conformational search ability of CAMDAS was evaluated using structurally known 281 protein-ligand complexes as a test set. For the test, the influences of initial settings and initial conformations on search results were validated. By using the CAMDAS program, reasonable conformations whose root mean square deviations (RMSDs) in comparison with crystal structures were less than 2.0 Å could be obtained from 96% of the test set even though the worst initial settings were used. The success rate was comparable to those of OMEGA, and the errors of CAMDAS were less than those of OMEGA. Based on the results obtained using CAMDAS, the worst RMSD was around 2.5 Å, although the worst value obtained was around 4.0 Å using OMEGA. The results indicated that CAMDAS is a robust and versatile conformational search method and that it can be used for a wide variety of small molecules. In addition, the accuracy of a conformational search in relation to this study was improved by longer MD calculations and multiple MD simulations.

  16. Intermanual transfer in training with an upper-limb myoelectric prosthesis simulator: a mechanistic, randomized, pretest-posttest study.

    PubMed

    Romkema, Sietske; Bongers, Raoul M; van der Sluis, Corry K

    2013-01-01

    Intermanual transfer may improve prosthetic handling and acceptance if used in training soon after an amputation. The purpose of this study was to determine whether intermanual transfer effects can be detected after training with a myoelectric upper-limb prosthesis simulator. A mechanistic, randomized, pretest-posttest design was used. A total of 48 right-handed participants (25 women, 23 men) who were able-bodied were randomly assigned to an experimental group or a control group. The experimental group performed a training program of 5 days' duration using the prosthesis simulator. To determine the improvement in skill, a test was administered before, immediately after, and 6 days after training. The control group only performed the tests. Training was performed with the unaffected arm, and tests were performed with the affected arm (the affected arm simulating an amputated limb). Half of the participants were tested with the dominant arm and half with the nondominant arm. Initiation time was defined as the time from starting signal until start of the movement, movement time was defined as the time from the beginning of the movement until completion of the task, and force control was defined as the maximal applied force on a deformable object. The movement time decreased significantly more in the experimental group (F₂,₉₂=7.42, P=.001, η²(G)=.028) when compared with the control group. This finding is indicative of faster handling of the prosthesis. No statistically significant differences were found between groups with regard to initiation time and force control. We did not find a difference in intermanual transfer between the dominant and nondominant arms. The training utilized participants who were able-bodied in a laboratory setting and focused only on transradial amputations. Intermanual transfer was present in the affected arm after training the unaffected arm with a myoelectric prosthesis simulator, and this effect did not depend on laterality. This effect may improve rehabilitation of patients with an upper-limb amputation.

  17. Inflatable Antenna for CubeSat: Extension of the Previously Developed S-Band Design to the X-Band

    NASA Technical Reports Server (NTRS)

    Babuscia, Alessandra; Choi, Thomas; Cheung, Kar-Ming; Thangavelautham, Jekan; Ravichandran, Mithun; Chandra, Aman

    2015-01-01

    The inflatable antenna for CubeSat is a 1 meter antenna reflector designed with one side reflective Mylar, another side clear Mylar with a patch antenna at the focus. The development of this technology responds to the increasing need for more capable communication systems to allow CubeSats to operate autonomously in interplanetary missions. An initial version of the antenna for the S-Band was developed and tested in both anechoic chamber and vacuum chamber. Recent developments in transceivers and amplifiers for CubeSat at X-band motivated the extension from the S-Band to the X-Band. This paper describes the process of extending the design of the antenna to the X-Band focusing on patch antenna redesign, new manufacturing challenges and initial results of experimental tests.

  18. Back-Face Strain for Monitoring Stable Crack Extension in Precracked Flexure Specimens

    NASA Technical Reports Server (NTRS)

    Salem, Jonathan A.; Ghosn, Louis J.

    2010-01-01

    Calibrations relating back-face strain to crack length in precracked flexure specimens were developed for different strain gage sizes. The functions were verified via experimental compliance measurements of notched and precracked ceramic beams. Good agreement between the functions and experiments occurred, and fracture toughness was calculated via several operational methods: maximum test load and optically measured precrack length; load at 2 percent crack extension and optical precrack length; maximum load and back-face strain crack length. All the methods gave vary comparable results. The initiation toughness, K(sub Ii) , was also estimated from the initial compliance and load.The results demonstrate that stability of precracked ceramics specimens tested in four-point flexure is a common occurrence, and that methods such as remotely-monitored load-point displacement are only adequate for detecting stable extension of relatively deep cracks.

  19. The Correlated Curriculum Project: A New Experimental Program for the General Student.

    ERIC Educational Resources Information Center

    Ford Foundation, New York, NY.

    The basic goal of the program is to initiate a new course of study which will upgrade the education of the general student and give him a sense of direction and commitment. The program was organized in five schools during the 1966 school year, and four additional high schools will be included in 1967. The Educational Testing Service of Princeton…

  20. Investigation of strength characteristics of aluminum alloy under dynamic tension

    NASA Astrophysics Data System (ADS)

    Evstifeev, A. D.

    2018-04-01

    The study presents the results of experimental-theoretical analysis for aluminum alloy subjected to static and dynamic tension on samples of different types. The material was tested under initial coarse-grained (CG) and in ultrafine-grained (UFG) condition. The time dependence of the tensile strength is calculated using an incubation time fracture criterion based on a set of fixed constants of the material.

  1. Atomic Energy Levels in Crystals

    DTIC Science & Technology

    1961-02-24

    testing, evaluation, calibration services, and various consultation and information servics. Research projecta are also performed for other government...agencies when the woric relates to and aupplementi the basic program of the Bureau or when the Bureau’s unique competence is requed aThe scope of...Johns Hopkins University, with the support of the U.S. Atomic Energy Commission, initiated a program of experimental studies of the sharp line

  2. An Initial Investigation into the Role of Stereotype Threat in the Test Performance of College Students with Learning Disabilities

    ERIC Educational Resources Information Center

    May, Alison L.; Stone, C. Addison

    2014-01-01

    In a quasi-experimental evaluation of the possible role of stereotype threat in the academic performance of college students with learning disabilities (LD), students with (N = 29) and without (N = 62) identified LD took a simulated Verbal GRE® task in one of two conditions modeled after those used in past stereotype threat (ST) research. The task…

  3. Experimental Civilian Personnel Office Project (EXPO): Final Report for Nonappropriated Fund Sites

    DTIC Science & Technology

    1991-07-01

    existing data bases; budgetary data; and other documents provided by the test sites. The results indicate that EXPO initiatives had a positive impact on...EXPO has had a positive impact on NAF operations and profitability of revenue-generating activities has remained stable. Important findings include...appropriate education and training resources are available. v viii VllI CONTENTS INTRO DU CTIO N

  4. Using Numerical Modeling to Simulate Space Capsule Ground Landings

    NASA Technical Reports Server (NTRS)

    Heymsfield, Ernie; Fasanella, Edwin L.

    2009-01-01

    Experimental work is being conducted at the National Aeronautics and Space Administration s (NASA) Langley Research Center (LaRC) to investigate ground landing capabilities of the Orion crew exploration vehicle (CEV). The Orion capsule is NASA s replacement for the Space Shuttle. The Orion capsule will service the International Space Station and be used for future space missions to the Moon and to Mars. To evaluate the feasibility of Orion ground landings, a series of capsule impact tests are being performed at the NASA Langley Landing and Impact Research Facility (LandIR). The experimental results derived at LandIR provide means to validate and calibrate nonlinear dynamic finite element models, which are also being developed during this study. Because of the high cost and time involvement intrinsic to full-scale testing, numerical simulations are favored over experimental work. Subsequent to a numerical model validated by actual test responses, impact simulations will be conducted to study multiple impact scenarios not practical to test. Twenty-one swing tests using the LandIR gantry were conducted during the June 07 through October 07 time period to evaluate the Orion s impact response. Results for two capsule initial pitch angles, 0deg and -15deg , along with their computer simulations using LS-DYNA are presented in this article. A soil-vehicle friction coefficient of 0.45 was determined by comparing the test stopping distance with computer simulations. In addition, soil modeling accuracy is presented by comparing vertical penetrometer impact tests with computer simulations for the soil model used during the swing tests.

  5. Temperature and Atomic Oxygen Effects on Helium Leak Rates of a Candidate Main Interface Seal

    NASA Technical Reports Server (NTRS)

    Penney, Nicholas; Wasowski, Janice L.; Daniels, Christopher C.

    2011-01-01

    Helium leak tests were completed to characterize the leak rate of a 54 in. diameter composite space docking seal design in support of the National Aeronautics and Space Administration s (NASA's) Low Impact Docking System (LIDS). The evaluated seal design was a candidate for the main interface seal on the LIDS, which would be compressed between two vehicles, while docked, to prevent the escape of breathable air from the vehicles and into the vacuum of space. Leak tests completed at nominal temperatures of -30, 20, and 50 C on untreated and atomic oxygen (AO) exposed test samples were examined to determine the influence of both test temperature and AO exposure on the performance of the composite seal assembly. Results obtained for untreated seal samples showed leak rates which increased with increased test temperature. This general trend was not observed in tests of the AO exposed specimens. Initial examination of collected test data suggested that AO exposure resulted in higher helium leak rates, however, further analysis showed that the differences observed in the 20 and 50 C tests between the untreated and AO exposed samples were within the experimental error of the test method. Lack of discernable trends in the test data prevented concrete conclusions about the effects of test temperature and AO exposure on helium leak rates of the candidate seal design from being drawn. To facilitate a comparison of the current test data with results from previous leak tests using air as the test fluid, helium leak rates were converted to air leak rates using standard conversion factors for viscous and molecular flow. Flow rates calculated using the viscous flow conversion factor were significantly higher than the experimental air leakage values, whereas values calculated using the molecular flow conversion factor were significantly lower than the experimentally obtained air leak rates. The difference in these sets of converted flow rates and their deviation from the experimentally obtained air leak rate data suggest that neither conversion factor can be used alone to accurately convert helium leak rates to equivalent air leak rates for the test seals evaluated in this study; other leak phenomena, including permeation, must also be considered.

  6. The Impact of Recreational Marijuana Legislation in Washington, DC on Marijuana Use Cognitions.

    PubMed

    Clarke, Paige; Dodge, Tonya; Stock, Michelle L

    2018-04-13

    There is little published research that tests the effect of recreational marijuana legislation on risk-related cognitions and how individuals respond immediately after legislative approval. The objective was to test whether learning about the passage of Initiative 71, a voter referendum that legalized recreational use of marijuana in the District of Columbia, would lead individuals to adopt more favorable marijuana cognitions than they had before the Initiative was passed. Undergraduate students (N = 402) completed two web-based questionnaires in 2014. The first questionnaire was completed prior to the referendum vote and the follow-up questionnaire was completed after voters approved Initiative 71. Attitudes, perceived norms, intentions, prototypes, and willingness were measured at time 1 and time 2. Study hypotheses were tested using repeated-measures analysis of covariance. Results showed that attitudes, intentions, perceived norms, and willingness to use marijuana were more favorable after Initiative 71 was passed. However, the increase in attitudes and willingness was moderated by past experience with marijuana whereby the increases were statistically significant only among those with the least experience. The increase in perceived norms was also moderated by past experience whereby increases were statistically significant among those who were moderate or heavy users. The passage of Initiative 71 had no effect on favorable prototypes. Conclusion/Importance: Legalization may have the unintended outcome of leading to more favorable intentions to use marijuana and might lead abstainers or experimental users to become more frequent users of marijuana via more positive attitudes and willingness towards marijuana use.

  7. Thermal stress response of General Purpose Heat Source (GPHS) aeroshell material

    NASA Technical Reports Server (NTRS)

    Grinberg, I. M.; Hulbert, L. E.; Luce, R. G.

    1980-01-01

    A thermal stress test was conducted to determine the ability of the GPHS aeroshell 3 D FWPF material to maintain physical integrity when exposed to a severe heat flux such as would occur from prompt reentry of GPHS modules. The test was performed in the Giant Planetary Facility at NASA's Ames Research Center. Good agreement was obtained between the theoretical and experimental results for both temperature and strain time histories. No physical damage was observed in the test specimen. These results provide initial corroboration both of the analysis techniques and that the GPHS reentry member will survive the reentry thermal stress levels expected.

  8. Specialised use of working memory by Portia africana, a spider-eating salticid.

    PubMed

    Cross, Fiona R; Jackson, Robert R

    2014-03-01

    Using expectancy-violation methods, we investigated the role of working memory in the predatory strategy of Portia africana, a salticid spider from Kenya that preys by preference on other spiders. One of this predator's tactics is to launch opportunistic leaping attacks on to other spiders in their webs. Focussing on this particular tactic, our experiments began with a test spider on a ramp facing a lure (dead prey spider mounted on a cork disc) that could be reached by leaping. After the test spider faced the lure for 30 s, we blocked the test spider's view of the lure by lowering an opaque shutter before the spider leapt. When the shutter was raised 90 s later, either the same lure came into view again (control) or a different lure came into view (experimental: different prey type in same orientation or same prey type in different orientation). We recorded attack frequency (number of test spiders that leapt at the lure) and attack latency (time elapsing between shutter being raised and spiders initiating a leap). Attack latencies in control trials were not significantly different from attack latencies in experimental trials, regardless of whether it was prey type or prey orientation that changed in the experimental trials. However, compared with test spiders in the no-change control trials, significantly fewer test spiders leapt when prey type changed. There was no significant effect on attack frequency when prey orientation changed. These findings suggest that this predator represents prey type independently of prey orientation.

  9. When does a strategy intervention overcome a failure of inhibition? Evidence from two left frontal brain tumour cases.

    PubMed

    Robinson, Gail A; Walker, David G; Biggs, Vivien; Shallice, Tim

    2016-06-01

    Initiation and inhibition of responses are crucial for appropriate behaviour across different settings. Initiation and inhibition difficulties are well documented following frontal damage, although task differences have limited our understanding. The Hayling Sentence Completion Test was designed to assess verbal initiation and inhibition within the same task. This study investigates the ability of two patients with left frontal tumours (KI: high grade glioma; PM: meningioma) to use a strategy to overcome profound suppression failures on the Hayling Test. KI and PM completed the Hayling Test and two experimental tasks. The Selection Investigation assessed verbal initiation on a sentence completion task that varied selection demands (high/low). The Suppression and Strategy Investigation assessed ability to implement four strategies aimed to override a suppression failure and facilitate production of an unconnected word. On the Hayling Test, KI and PM initiated responses to complete high constraint sentences, in contrast to impaired suppression. KI benefitted minimally from strategies to overcome suppression failure although one strategy (object naming) was partially successful. KI's errors revealed fast suppression errors, in contrast to slow no responses, and selection ability was also impaired for verbal initiation. PM, however, implemented each strategy 100% to overcome a suppression failure and had no difficulty completing sentences meaningfully, regardless of selection demands. This first investigation of strategy implementation to overcome profound suppression impairments provides insights into verbal initiation, inhibition, selection and strategy mechanisms, which has implications for neurorehabilitation. Specifically, both patients had profound inhibition deficits but KI also presented with a selection deficit and was unable to implement a strategy. By contrast, PM's selection ability was intact but she was unable to generate, rather than implement, a strategy. We suggest that KI has both fast, uncontrolled semantic output and response inhibition difficulty, whereas PM's difficulty is underpinned by motivational factors. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Development and Test Evaluations for Ni-DOBDC Metal Organic Framework (MOF) Engineered Forms

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

    Troy G. Garn; Mitchell Greenhalgh

    2013-07-01

    A joint effort to prepare engineered forms of a Ni-DOBDC metal organic framework (MOF) was completed with contributions from PNNL, SNL and the INL. Two independent methods were used at INL and SNL to prepare engineered form (EF) sorbents from Ni-DOBDC MOF powder developed and prepared at PNNL. Xe and Kr capacity test evaluations were performed at ambient temperature with the cryostat experimental setup at INL. The initial INL EF MOF test results indicated a Xe capacity of 1.6 mmol/kg sorbent and no Kr capacity. A large loss of surface area also occurred during minimal testing rendering the INL EFmore » MOF unusable. Four capacity tests were completed using the SNL EF MOF at ambient temperature and resulted in Xe capacities of 1.4, 4.2, 5.0 and 3.8 mmol/kg sorbent with no Kr capacity observed in any ambient temperature tests. Two additional capacity tests were performed at 240 K to further evaluate SNL EF MOF performance. Xe capacities of 50.7 and 49.3 mmol/kg of sorbent and Kr capacities of 0.77 and 0.69 mmol/kg of sorbent were obtained, respectively. Following the adsorption evaluations, the SNL EF MOF material had lost about 40 % of the initial mass and 40 % of the initial surface area. In general, the Xe capacity results at ambient temperature for the INL and SNL EF Ni-DOBDC MOF’s were lower than 9.8 mmol Xe/kg sorbent test results reported by INL in FY-12 using PNNL’s inital EF supplied material.« less

  11. Experimental investigation of a 2.5 centimeter diameter Kaufman microthruster

    NASA Technical Reports Server (NTRS)

    Cohen, A. J.

    1973-01-01

    A 2.5-centimeter-diameter Kaufman electron bombardment microthruster was fabricated and tested. The microthruster design was based on the 15-centimeter-diameter SERT 2 and 5-centimeter-diameter Lewis experimental thruster designs. The microthruster with a two-grid system, operating at a net accelerating potential of 600 volts and an accelerator potential of 500 volts, produced a calculated 445 micronewton thrust when it was run with a 9-milliampere beam current. A glass grid was initially used in testing. Later a two-grid system was successfully incorporated. Both the propellant utilization efficiency and the total power efficiency were lower than for large-size advanced thrusters, as expected; but they were sufficiently high that 2.5-centimeter thrusters show promise for future space applications. Total power of the microthruster with an assumed 7-watt hollow-cathode neutralizer was less than 30 watts at a thrust level of 445 micronewton (100 Nu LBf). The hollow cathode was operated at zero tip heater power for power requirement tests.

  12. Strain rate sensitivity of the tensile strength of two silicon carbides: experimental evidence and micromechanical modelling

    NASA Astrophysics Data System (ADS)

    Zinszner, Jean-Luc; Erzar, Benjamin; Forquin, Pascal

    2017-01-01

    Ceramic materials are commonly used to design multi-layer armour systems thanks to their favourable physical and mechanical properties. However, during an impact event, fragmentation of the ceramic plate inevitably occurs due to its inherent brittleness under tensile loading. Consequently, an accurate model of the fragmentation process is necessary in order to achieve an optimum design for a desired armour configuration. In this work, shockless spalling tests have been performed on two silicon carbide grades at strain rates ranging from 103 to 104 s-1 using a high-pulsed power generator. These spalling tests characterize the tensile strength strain rate sensitivity of each ceramic grade. The microstructural properties of the ceramics appear to play an important role on the strain rate sensitivity and on the dynamic tensile strength. Moreover, this experimental configuration allows for recovering damaged, but unbroken specimens, giving unique insight on the fragmentation process initiated in the ceramics. All the collected data have been compared with corresponding results of numerical simulations performed using the Denoual-Forquin-Hild anisotropic damage model. Good agreement is observed between numerical simulations and experimental data in terms of free surface velocity, size and location of the damaged zones along with crack density in these damaged zones. This article is part of the themed issue 'Experimental testing and modelling of brittle materials at high strain rates'.

  13. Flatworm models in pharmacological research: the importance of compound stability testing.

    PubMed

    Stalmans, Sofie; Willems, Maxime; Adriaens, Els; Remon, Jean-Paul; D'Hondt, Matthias; De Spiegeleer, Bart

    2014-10-01

    Flatworms possess adult pluripotent stem cells, which make them extraordinary experimental model organisms to assess in vivo the undesirable effects of substances on stem cells. Currently, quality practices, implying evaluation of the stability of the test compound under the proposed experimental conditions, are uncommon in this research field. Nevertheless, performing a stability study during the rational design of in vivo assay protocols will result in more reliable assay results. To illustrate the influence of the stability of the test substance on the final experimental outcome, we performed a short-term International Conference on Harmonization (ICH)-based stability study of cyclophosphamide in the culture medium, to which a marine flatworm model Macrostomum lignano is exposed. Using a validated U(H)PLC method, it was demonstrated that the cyclophosphamide concentration in the culture medium at 20°C is lowered to 80% of the initial concentration after 21days. The multiwell plates, flatworms and diatoms, as well as light exposure, did not influence significantly the cyclophosphamide concentration in the medium. The results of the stability study have practical implications on the experimental set-up of the carcinogenicity assay like the frequency of medium renewal. This case study demonstrates the benefits of applying appropriate quality guidelines already during fundamental research increasing the credibility of the results. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Strain rate sensitivity of the tensile strength of two silicon carbides: experimental evidence and micromechanical modelling.

    PubMed

    Zinszner, Jean-Luc; Erzar, Benjamin; Forquin, Pascal

    2017-01-28

    Ceramic materials are commonly used to design multi-layer armour systems thanks to their favourable physical and mechanical properties. However, during an impact event, fragmentation of the ceramic plate inevitably occurs due to its inherent brittleness under tensile loading. Consequently, an accurate model of the fragmentation process is necessary in order to achieve an optimum design for a desired armour configuration. In this work, shockless spalling tests have been performed on two silicon carbide grades at strain rates ranging from 10 3 to 10 4  s -1 using a high-pulsed power generator. These spalling tests characterize the tensile strength strain rate sensitivity of each ceramic grade. The microstructural properties of the ceramics appear to play an important role on the strain rate sensitivity and on the dynamic tensile strength. Moreover, this experimental configuration allows for recovering damaged, but unbroken specimens, giving unique insight on the fragmentation process initiated in the ceramics. All the collected data have been compared with corresponding results of numerical simulations performed using the Denoual-Forquin-Hild anisotropic damage model. Good agreement is observed between numerical simulations and experimental data in terms of free surface velocity, size and location of the damaged zones along with crack density in these damaged zones.This article is part of the themed issue 'Experimental testing and modelling of brittle materials at high strain rates'. © 2016 The Author(s).

  15. Strain rate sensitivity of the tensile strength of two silicon carbides: experimental evidence and micromechanical modelling

    PubMed Central

    Erzar, Benjamin

    2017-01-01

    Ceramic materials are commonly used to design multi-layer armour systems thanks to their favourable physical and mechanical properties. However, during an impact event, fragmentation of the ceramic plate inevitably occurs due to its inherent brittleness under tensile loading. Consequently, an accurate model of the fragmentation process is necessary in order to achieve an optimum design for a desired armour configuration. In this work, shockless spalling tests have been performed on two silicon carbide grades at strain rates ranging from 103 to 104 s−1 using a high-pulsed power generator. These spalling tests characterize the tensile strength strain rate sensitivity of each ceramic grade. The microstructural properties of the ceramics appear to play an important role on the strain rate sensitivity and on the dynamic tensile strength. Moreover, this experimental configuration allows for recovering damaged, but unbroken specimens, giving unique insight on the fragmentation process initiated in the ceramics. All the collected data have been compared with corresponding results of numerical simulations performed using the Denoual–Forquin–Hild anisotropic damage model. Good agreement is observed between numerical simulations and experimental data in terms of free surface velocity, size and location of the damaged zones along with crack density in these damaged zones. This article is part of the themed issue ‘Experimental testing and modelling of brittle materials at high strain rates’. PMID:27956504

  16. [Learning to use semiautomatic external defibrillators through audiovisual materials for schoolchildren].

    PubMed

    Jorge-Soto, Cristina; Abelairas-Gómez, Cristian; Barcala-Furelos, Roberto; Gregorio-García, Carolina; Prieto-Saborit, José Antonio; Rodríguez-Núñez, Antonio

    2016-01-01

    To assess the ability of schoolchildren to use a automated external defibrillator (AED) to provide an effective shock and their retention of the skill 1 month after a training exercise supported by audiovisual materials. Quasi-experimental controlled study in 205 initially untrained schoolchildren aged 6 to 16 years old. SAEDs were used to apply shocks to manikins. The students took a baseline test (T0) of skill, and were then randomized to an experimental or control group in the first phase (T1). The experimental group watched a training video, and both groups were then retested. The children were tested in simulations again 1 month later (T2). A total of 196 students completed all 3 phases. Ninety-six (95.0%) of the secondary school students and 54 (56.8%) of the primary schoolchildren were able to explain what a SAED is. Twenty of the secondary school students (19.8%) and 8 of the primary schoolchildren (8.4%) said they knew how to use one. At T0, 78 participants (39.8%) were able to simulate an effective shock. At T1, 36 controls (34.9%) and 56 experimental-group children (60.2%) achieved an effective shock (P< .001). At T2, 53 controls (51.4%) and 61 experimental-group children (65.6%) gave effective shocks (P=.045). All the students completed the tests in 120 seconds. Their average times decreased with each test. The secondary school students achieved better results. Previously untrained secondary school students know what a AED is and half of them can manage to use one in simulations. Brief narrative, audiovisual instruction improves students' skill in managing a SAED and helps them retain what they learned for later use.

  17. Preliminary Computational Analysis of the (HIRENASD) Configuration in Preparation for the Aeroelastic Prediction Workshop

    NASA Technical Reports Server (NTRS)

    Chwalowski, Pawel; Florance, Jennifer P.; Heeg, Jennifer; Wieseman, Carol D.; Perry, Boyd P.

    2011-01-01

    This paper presents preliminary computational aeroelastic analysis results generated in preparation for the first Aeroelastic Prediction Workshop (AePW). These results were produced using FUN3D software developed at NASA Langley and are compared against the experimental data generated during the HIgh REynolds Number Aero- Structural Dynamics (HIRENASD) Project. The HIRENASD wind-tunnel model was tested in the European Transonic Windtunnel in 2006 by Aachen University0s Department of Mechanics with funding from the German Research Foundation. The computational effort discussed here was performed (1) to obtain a preliminary assessment of the ability of the FUN3D code to accurately compute physical quantities experimentally measured on the HIRENASD model and (2) to translate the lessons learned from the FUN3D analysis of HIRENASD into a set of initial guidelines for the first AePW, which includes test cases for the HIRENASD model and its experimental data set. This paper compares the computational and experimental results obtained at Mach 0.8 for a Reynolds number of 7 million based on chord, corresponding to the HIRENASD test conditions No. 132 and No. 159. Aerodynamic loads and static aeroelastic displacements are compared at two levels of the grid resolution. Harmonic perturbation numerical results are compared with the experimental data using the magnitude and phase relationship between pressure coefficients and displacement. A dynamic aeroelastic numerical calculation is presented at one wind-tunnel condition in the form of the time history of the generalized displacements. Additional FUN3D validation results are also presented for the AGARD 445.6 wing data set. This wing was tested in the Transonic Dynamics Tunnel and is commonly used in the preliminary benchmarking of computational aeroelastic software.

  18. Damage Mechanisms and Controlled Crack Propagation in a Hot Pressed Silicon Nitride Ceramic. Ph.D. Thesis - Northwestern Univ., 1993

    NASA Technical Reports Server (NTRS)

    Calomino, Anthony Martin

    1994-01-01

    The subcritical growth of cracks from pre-existing flaws in ceramics can severely affect the structural reliability of a material. The ability to directly observe subcritical crack growth and rigorously analyze its influence on fracture behavior is important for an accurate assessment of material performance. A Mode I fracture specimen and loading method has been developed which permits the observation of stable, subcritical crack extension in monolithic and toughened ceramics. The test specimen and procedure has demonstrated its ability to generate and stably propagate sharp, through-thickness cracks in brittle high modulus materials. Crack growth for an aluminum oxide ceramic was observed to be continuously stable throughout testing. Conversely, the fracture behavior of a silicon nitride ceramic exhibited crack growth as a series of subcritical extensions which are interrupted by dynamic propagation. Dynamic initiation and arrest fracture resistance measurements for the silicon nitride averaged 67 and 48 J/sq m, respectively. The dynamic initiation event was observed to be sudden and explosive. Increments of subcritical crack growth contributed to a 40 percent increase in fracture resistance before dynamic initiation. Subcritical crack growth visibly marked the fracture surface with an increase in surface roughness. Increments of subcritical crack growth loosen ceramic material near the fracture surface and the fracture debris is easily removed by a replication technique. Fracture debris is viewed as evidence that both crack bridging and subsurface microcracking may be some of the mechanisms contributing to the increase in fracture resistance. A Statistical Fracture Mechanics model specifically developed to address subcritical crack growth and fracture reliability is used together with a damaged zone of material at the crack tip to model experimental results. A Monte Carlo simulation of the actual experiments was used to establish a set of modeling input parameters. It was demonstrated that a single critical parameter does not characterize the conditions required for dynamic initiation. Experimental measurements for critical crack lengths, and the energy release rates exhibit significant scatter. The resulting output of the model produces good agreement with both the average values and scatter of experimental measurements.

  19. Design, Optimization, and Evaluation of Integrally-Stiffened Al-2139 Panel with Curved Stiffeners

    NASA Technical Reports Server (NTRS)

    Havens, David; Shiyekar, Sandeep; Norris, Ashley; Bird, R. Keith; Kapania, Rakesh K.; Olliffe, Robert

    2011-01-01

    A curvilinear stiffened panel was designed, manufactured, and tested in the Combined Load Test Fixture at NASA Langley Research Center. The panel is representative of a large wing engine pylon rib and was optimized for minimum mass subjected to three combined load cases. The optimization included constraints on web buckling, material yielding, crippling or local stiffener failure, and damage tolerance using a new analysis tool named EBF3PanelOpt. Testing was performed for the critical combined compression-shear loading configuration. The panel was loaded beyond initial buckling, and strains and out-of-plane displacements were extracted from a total of 20 strain gages and 6 linear variable displacement transducers. The VIC-3D system was utilized to obtain full field displacements/strains in the stiffened side of the panel. The experimental data were compared with the strains and out-of-plane deflections from a high fidelity nonlinear finite element analysis. The experimental data were also compared with linear elastic finite element results of the panel/test-fixture assembly. Overall, the panel buckled very near to the predicted load in the web regions.

  20. Novel Transparent Urinary Tract Simulator Improves Teaching of Urological Operation Skills at a Single Institution.

    PubMed

    Zhong, Xiao; Wang, Pingxian; Feng, Jiayu; Hu, Wengang; Huang, Chibing

    2015-01-01

    This randomized controlled study compared a novel transparent urinary tract simulator with the traditional opaque urinary tract simulator as an aid for efficiently teaching urological surgical procedures. Senior medical students were tested on their understanding of urological theory before and after lectures concerning urinary system disease. The students received operative training using the transparent urinary tract simulator (experimental group, n = 80) or the J3311 opaque plastic urinary tract simulator (control, n = 80), specifically in catheterization and retrograde double-J stent implantation. The operative training was followed by a skills test and student satisfaction survey. The test scores for theory were similar between the two groups, before and after training. Students in the experimental group performed significantly better than those in the control group on the procedural skills test, and also had significantly better self-directed learning skills, analytical skills, and greater motivation to learn. During the initial step of training, the novel transparent urinary tract simulator significantly improved the efficiency of teaching urological procedural skills compared with the traditional opaque device. © 2015 S. Karger AG, Basel.

  1. A microstructurally based model of solder joints under conditions of thermomechanical fatigue

    NASA Astrophysics Data System (ADS)

    Frear, D. R.; Burchett, S. N.; Rashid, M. M.

    The thermomechanical fatigue failure of solder joints is increasingly becoming an important reliability issue. We present two computational methodologies that have been developed to predict the behavior of near eutectic Sn-Pb solder joints under fatigue conditions that are based on metallurgical tests as fundamental input for constitutive relations. The two-phase model mathematically predicts the heterogeneous coarsening behavior of near eutectic Sn-Pb solder. The finite element simulations from this model agree well with experimental thermomechanical fatigue tests. The simulations show that the presence of an initial heterogeneity in the solder microstructure could significantly degrade the fatigue lifetime. The single phase model is a computational technique that was developed to predict solder joint behavior using materials data for constitutive relation constants that could be determined through straightforward metallurgical experiments. A shear/torsion test sample was developed to impose strain in two different orientations. Materials constants were derived from these tests and the results showed an adequate fit to experimental results. The single-phase model could be very useful for conditions where microstructural evolution is not a dominant factor in fatigue.

  2. The characterization of widespread fatigue damage in fuselage structure

    NASA Technical Reports Server (NTRS)

    Piascik, Robert S.; Willard, Scott A.; Miller, Matthew

    1994-01-01

    The characteristics of widespread fatigue damage (WSFD) in fuselage riveted structure were established by detailed nondestructive and destructive examinations of fatigue damage contained in a full size fuselage test article. The objectives of this were to establish an experimental data base for validating emerging WSFD analytical prediction methodology and to identify first order effects that contribute to fatigue crack initiation and growth. Detailed examinations were performed on a test panel containing four bays of a riveted lap splice joint. The panel was removed from a full scale fuselage test article after receiving 60,000 full pressurization cycles. The results of in situ examinations document the progression of fuselage skin fatigue crack growth through crack linkup. Detailed tear down examinations and fractography of the lap splice joint region revealed fatigue crack initiation sites, crack morphology, and crack linkup geometry. From this large data base, distributions of crack size and locations are presented and discussions of operative damage mechanisms are offered.

  3. The characterization of widespread fatigue damage in fuselage structure

    NASA Technical Reports Server (NTRS)

    Piascik, Robert S.; Willard, Scott A.; Miller, Matthew

    1994-01-01

    The characteristics of widespread fatigue damage (WSFD) in fuselage riveted structure were established by detailed nondestructive and destructive examinations of fatigue damage contained in a full size fuselage test article. The objectives of this work were to establish an experimental data base for validating emerging WSFD analytical prediction methodology and to identify first order effects that contribute to fatigue crack initiation and growth. Detailed examinations were performed on a test panel containing four bays of a riveted lap splice joint. The panel was removed from a full scale fuselage test article after receiving 60,000 full pressurization cycles. The results of in situ examinations document the progression of fuselage skin fatigue crack growth through crack linkup. Detailed tear down examinations and fractography of the lap splice joint region revealed fatigue crack initiation sites, crack morphology and crack linkup geometry. From this large data base, distributions of crack size and locations are presented and discussions of operative damage mechanisms are offered.

  4. Atmosphere behavior in gas-closed mouse-algal systems - An experimental and modelling study

    NASA Technical Reports Server (NTRS)

    Averner, M. M.; Moore, B., III; Bartholomew, I.; Wharton, R.

    1984-01-01

    A NASA-sponsored research program initiated using mathematical modelling and laboratory experimentation aimed at examining the gas-exchange characteristics of artificial animal/plant systems closed to the ambient atmosphere is studied. The development of control techniques and management strategies for maintaining the atmospheric levels of carbon dioxide and oxygen at physiological levels is considered. A mathematical model simulating the behavior of a gas-closed mouse-algal system under varying environmental conditions is described. To verify and validate the model simulations, an analytical system with which algal growth and gas exchange characteristics can be manipulated and measured is designed, fabricated, and tested. The preliminary results are presented.

  5. An adaptive controller for enhancing operator performance during teleoperation

    NASA Technical Reports Server (NTRS)

    Carignan, Craig R.; Tarrant, Janice M.; Mosier, Gary E.

    1989-01-01

    An adaptive controller is developed for adjusting robot arm parameters while manipulating payloads of unknown mass and inertia. The controller is tested experimentally in a master/slave configuration where the adaptive slave arm is commanded via human operator inputs from a master. Kinematically similar six-joint master and slave arms are used with the last three joints locked for simplification. After a brief initial adaptation period for the unloaded arm, the slave arm retrieves different size payloads and maneuvers them about the workspace. Comparisons are then drawn with similar tasks where the adaptation is turned off. Several simplifications of the controller dynamics are also addressed and experimentally verified.

  6. A Hybrid Actuation System Demonstrating Significantly Enhanced Electromechanical Performance

    NASA Technical Reports Server (NTRS)

    Su, Ji; Xu, Tian-Bing; Zhang, Shujun; Shrout, Thomas R.; Zhang, Qiming

    2004-01-01

    A hybrid actuation system (HYBAS) utilizing advantages of a combination of electromechanical responses of an electroactive polymer (EAP), an electrostrictive copolymer, and an electroactive ceramic single crystal, PZN-PT single crystal, has been developed. The system employs the contribution of the actuation elements cooperatively and exhibits a significantly enhanced electromechanical performance compared to the performances of the device made of each constituting material, the electroactive polymer or the ceramic single crystal, individually. The theoretical modeling of the performances of the HYBAS is in good agreement with experimental observation. The consistence between the theoretical modeling and experimental test make the design concept an effective route for the development of high performance actuating devices for many applications. The theoretical modeling, fabrication of the HYBAS and the initial experimental results will be presented and discussed.

  7. Improvements in High Speed, High Resolution Dynamic Digital Image Correlation for Experimental Evaluation of Composite Drive System Components

    NASA Technical Reports Server (NTRS)

    Kohlman, Lee W.; Ruggeri, Charles R.; Roberts, Gary D.; Handschuh, Robert Frederick

    2013-01-01

    Composite materials have the potential to reduce the weight of rotating drive system components. However, these components are more complex to design and evaluate than static structural components in part because of limited ability to acquire deformation and failure initiation data during dynamic tests. Digital image correlation (DIC) methods have been developed to provide precise measurements of deformation and failure initiation for material test coupons and for structures under quasi-static loading. Attempts to use the same methods for rotating components (presented at the AHS International 68th Annual Forum in 2012) are limited by high speed camera resolution, image blur, and heating of the structure by high intensity lighting. Several improvements have been made to the system resulting in higher spatial resolution, decreased image noise, and elimination of heating effects. These improvements include the use of a high intensity synchronous microsecond pulsed LED lighting system, different lenses, and changes in camera configuration. With these improvements, deformation measurements can be made during rotating component tests with resolution comparable to that which can be achieved in static tests

  8. Improvements in High Speed, High Resolution Dynamic Digital Image Correlation for Experimental Evaluation of Composite Drive System Components

    NASA Technical Reports Server (NTRS)

    Kohlman, Lee; Ruggeri, Charles; Roberts, Gary; Handshuh, Robert

    2013-01-01

    Composite materials have the potential to reduce the weight of rotating drive system components. However, these components are more complex to design and evaluate than static structural components in part because of limited ability to acquire deformation and failure initiation data during dynamic tests. Digital image correlation (DIC) methods have been developed to provide precise measurements of deformation and failure initiation for material test coupons and for structures under quasi-static loading. Attempts to use the same methods for rotating components (presented at the AHS International 68th Annual Forum in 2012) are limited by high speed camera resolution, image blur, and heating of the structure by high intensity lighting. Several improvements have been made to the system resulting in higher spatial resolution, decreased image noise, and elimination of heating effects. These improvements include the use of a high intensity synchronous microsecond pulsed LED lighting system, different lenses, and changes in camera configuration. With these improvements, deformation measurements can be made during rotating component tests with resolution comparable to that which can be achieved in static tests.

  9. Experimental characterization and microstructure linked modeling of mechanical behavior of ultra-thin aluminum foils used in packaging

    NASA Astrophysics Data System (ADS)

    Tabourot, Laurent; Charleux, Ludovic; Balland, Pascale; Sène, Ndèye Awa; Andreasson, Eskil

    2018-05-01

    This paper is based on the hypothesis that introducing distribution of mechanical properties is beneficial for modeling all kinds of mechanical behavior, even of ordinary metallic materials. To bring proof of its admissibility, it has to be first shown that modeling based on this assertion is able to efficiently describe standard mechanical behavior of materials. Searching for typical study case, it has been assessed that at a low scale, yield stresses could be strongly distributed in ultrathin aluminum foils used in packaging industry, offering opportunities to identifying their distribution and showing its role on the mechanical properties. Considering initially reduced modeling allow to establish a valuable connection between the hardening curve and the distribution of local yield stresses. This serves for finding initial value of distribution parameters in a more sophisticated identification procedure. With finally limited number of representative classes of local yield stresses, concretely 3 is enough, it is shown that a 3D finite element simulation involving limited numbers of elements returns realistic behavior of an ultrathin aluminum foil exerted to tensile test, in reference to experimental results. This gives way to large possibilities in modeling in order to give back complex experimental evidence.

  10. Simulations of the Richtmyer-Meshkov Instability in a two-shock vertical shock tube

    NASA Astrophysics Data System (ADS)

    Ferguson, Kevin; Olson, Britton; Jacobs, Jeffrey

    2017-11-01

    Simulations of the Richtmyer-Meshkov Instability (RMI) in a new two-shock vertical shock tube configuration are presented. The simulations are performed using the ARES code at Lawrence-Livermore National Laboratory (LLNL). Two M=1.2 shock waves travel in opposing directions and impact an initially stationary interface formed by sulfur hexaflouride (SF6) and air. The delay between the two shocks is controlled to achieve a prescribed temporal separation in shock wave arrival time. Initial interface perturbations and diffusion profiles are generated in keeping with previously gathered experimental data. The effect of varying the inter-shock delay and initial perturbation structure on instability growth and mixing parameters is examined. Information on the design, construction, and testing of a new two-shock vertical shock tube are also presented.

  11. Thermodynamics of reformulated automotive fuels

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

    Zudkevitch, D.; Murthy, A.K.S.; Gmehling, J.

    1995-06-01

    Two methods for predicting Reid vapor pressure (Rvp) and initial vapor emissions of reformulated gasoline blends that contain one or more oxygenated compounds show excellent agreement with experimental data. In the first method, method A, D-86 distillation data for gasoline blends are used for predicting Rvp from a simulation of the mini dry vapor pressure equivalent (Dvpe) experiment. The other method, method B, relies on analytical information (PIANO analyses) of the base gasoline and uses classical thermodynamics for simulating the same Rvp equivalent (Rvpe) mini experiment. Method B also predicts composition and other properties for the fuel`s initial vapor emission.more » Method B, although complex, is more useful in that is can predict properties of blends without a D-86 distillation. An important aspect of method B is its capability to predict composition of initial vapor emissions from gasoline blends. Thus, it offers a powerful tool to planners of gasoline blending. Method B uses theoretically sound formulas, rigorous thermodynamic routines and uses data and correlations of physical properties that are in the public domain. Results indicate that predictions made with both methods agree very well with experimental values of Dvpe. Computer simulation methods were programmed and tested.« less

  12. Experimental Study of Thermal Runaway Process of 18650 Lithium-Ion Battery

    PubMed Central

    Liu, Jingjing; Wang, Zhirong; Gong, Junhui; Liu, Kai; Wang, Hao; Guo, Linsheng

    2017-01-01

    This study addresses the effects of the SOC (State of Charge) and the charging–discharging process on the thermal runaway of 18650 lithium-ion batteries. A series of experiments were conducted on an electric heating and testing apparatus. The experimental results indicate that 6 W is the critical heating power for 40% SOC. With a 20 W constant heating rate, the thermal runaway initial temperature of the lithium-ion battery decreases with the increasing SOC. The final thermal runaway temperature increases with the SOC when the SOC is lower than 80%. However, a contrary conclusion was obtained when the SOC was higher than 80%. Significant mass loss, accompanied by an intense exothermic reaction, took place under a higher SOC. The critical charging current, beyond which the thermal runaway occurs, was found to be 2.6 A. The thermal runaway initial temperature decreases with the increasing charging current, while the intensity of the exothermic reaction varies inversely. Mass ejection of gas and electrolytes exists during thermal runaway when the charging current is higher than 10.4 A, below which only a large amount of gas is released. The thermal runaway initial temperature of discharging is higher than that of non-discharging. PMID:28772588

  13. Experimental Study of Thermal Runaway Process of 18650 Lithium-Ion Battery.

    PubMed

    Liu, Jingjing; Wang, Zhirong; Gong, Junhui; Liu, Kai; Wang, Hao; Guo, Linsheng

    2017-02-25

    This study addresses the effects of the SOC (State of Charge) and the charging-discharging process on the thermal runaway of 18650 lithium-ion batteries. A series of experiments were conducted on an electric heating and testing apparatus. The experimental results indicate that 6 W is the critical heating power for 40% SOC. With a 20 W constant heating rate, the thermal runaway initial temperature of the lithium-ion battery decreases with the increasing SOC. The final thermal runaway temperature increases with the SOC when the SOC is lower than 80%. However, a contrary conclusion was obtained when the SOC was higher than 80%. Significant mass loss, accompanied by an intense exothermic reaction, took place under a higher SOC. The critical charging current, beyond which the thermal runaway occurs, was found to be 2.6 A. The thermal runaway initial temperature decreases with the increasing charging current, while the intensity of the exothermic reaction varies inversely. Mass ejection of gas and electrolytes exists during thermal runaway when the charging current is higher than 10.4 A, below which only a large amount of gas is released. The thermal runaway initial temperature of discharging is higher than that of non-discharging.

  14. The effect of resource history on the functioning of soil microbial communities is maintained across time

    NASA Astrophysics Data System (ADS)

    Keiser, A. D.; Strickland, M. S.; Fierer, N.; Bradford, M. A.

    2011-02-01

    Historical resource conditions appear to influence microbial community function. With time, historical influences might diminish as populations respond to the contemporary environment. Alternatively, they may persist given factors such as contrasting genetic potentials for adaptation to a new environment. Using experimental microcosms, we test competing hypotheses that function of distinct soil microbial communities in common environments (H1a) converge or (H1b) remain dissimilar over time. Using a 6 × 2 (soil community inoculum × litter environment) full-factorial design, we compare decomposition rates in experimental microcosms containing grass or hardwood litter environments. After 100 days, communities that develop are inoculated into fresh litters and decomposition followed for another 100 days. We repeat this for a third, 100-day period. In each successive, 100-day period, we find higher decomposition rates (i.e. functioning) suggesting communities function better when they have an experimental history of the contemporary environment. Despite these functional gains, differences in decomposition rates among initially distinct communities persist, supporting the hypothesis that dissimilarity is maintained across time. In contrast to function, community composition is more similar following a common, experimental history. We also find that "specialization" on one experimental environment incurs a cost, with loss of function in the alternate environment. For example, experimental history of a grass-litter environment reduced decomposition when communities were inoculated into a hardwood-litter environment. Our work demonstrates experimentally that despite expectations of fast growth rates, physiological flexibility and rapid evolution, initial functional differences between microbial communities are maintained across time. These findings question whether microbial dynamics can be omitted from models of ecosystem processes if we are to predict reliably global change effects on biogeochemical cycles.

  15. The effect of resource history on the functioning of soil microbial communities is maintained across time

    NASA Astrophysics Data System (ADS)

    Keiser, A. D.; Strickland, M. S.; Fierer, N.; Bradford, M. A.

    2011-06-01

    Historical resource conditions appear to influence microbial community function. With time, historical influences might diminish as populations respond to the contemporary environment. Alternatively, they may persist given factors such as contrasting genetic potentials for adaptation to a new environment. Using experimental microcosms, we test competing hypotheses that function of distinct soil microbial communities in common environments (H1a) converge or (H1b) remain dissimilar over time. Using a 6 × 2 (soil community inoculum × litter environment) full-factorial design, we compare decomposition rates in experimental microcosms containing grass or hardwood litter environments. After 100 days, communities that develop are inoculated into fresh litters and decomposition followed for another 100 days. We repeat this for a third, 100-day period. In each successive, 100-day period, we find higher decomposition rates (i.e. functioning) suggesting communities function better when they have an experimental history of the contemporary environment. Despite these functional gains, differences in decomposition rates among initially distinct communities persist, supporting the hypothesis that dissimilarity is maintained across time. In contrast to function, community composition is more similar following a common, experimental history. We also find that "specialization" on one experimental environment incurs a cost, with loss of function in the alternate environment. For example, experimental history of a grass-litter environment reduced decomposition when communities were inoculated into a hardwood-litter environment. Our work demonstrates experimentally that despite expectations of fast growth rates, physiological flexibility and rapid evolution, initial functional differences between microbial communities are maintained across time. These findings question whether microbial dynamics can be omitted from models of ecosystem processes if we are to predict reliably global change effects on biogeochemical cycles.

  16. Preschool life skills: Recent advancements and future directions.

    PubMed

    Fahmie, Tara A; Luczynski, Kevin C

    2018-01-01

    Over the past decade, researchers have replicated and extended research on the preschool life skills (PLS) program developed by Hanley, Heal, Tiger, and Ingvarsson (2007). This review summarizes recent research with respect to maximizing skill acquisition, improving generality, evaluating feasibility and acceptability, and testing predictions of the initial PLS study. For each area, we suggest directions for future research. © 2018 Society for the Experimental Analysis of Behavior.

  17. Modelling of the Impact Response of Fibre-Reinforced Composites

    DTIC Science & Technology

    1990-09-30

    observed under tensile loading alone, the damage accumulation process following initial tensile fracture of a fibre tow somewhere within the test specimen...results to be obtained which are not inconsistent with those observed experimentally. Sim- ilarly the delamination process is modelled assuming an...publication either in journals or in conference proceedings. 1 . J. Harding and K. Saka, "The effect of strain rate on the tensile failure of woven reinforced

  18. Delaminations in composite plates under transverse static loads - Experimental results

    NASA Technical Reports Server (NTRS)

    Finn, Scott R.; He, Yi-Fei; Springer, George S.

    1992-01-01

    Tests were performed measuring the damage initiation loads and the locations, shapes, and sizes of delaminations in Fiberite T300/976 graphite/epoxy, Fiberite IM7/977-2 graphite-toughened epoxy, and ICI APC-2 graphite-PEEK plates subjected to transverse static loads. The data were compared to the results of the Finn-Springer model, and good agreements were found between the measured and calculated delamination lengths and widths.

  19. In situ recording of particle network formation in liquids by ion conductivity measurements.

    PubMed

    Pfaffenhuber, Christian; Sörgel, Seniz; Weichert, Katja; Bele, Marjan; Mundinger, Tabea; Göbel, Marcus; Maier, Joachim

    2011-09-21

    The formation of fractal silica networks from a colloidal initial state was followed in situ by ion conductivity measurements. The underlying effect is a high interfacial lithium ion conductivity arising when silica particles are brought into contact with Li salt-containing liquid electrolytes. The experimental results were modeled using Monte Carlo simulations and tested using confocal fluorescence laser microscopy and ζ-potential measurements.

  20. Electric power generation using geothermal brine resources for a proof of concept facility

    NASA Technical Reports Server (NTRS)

    Hankin, J. W.

    1974-01-01

    An exploratory systems study of a geothermal proof-of-concept facility is being conducted. This study is the initial phase (Phase 0) of a project to establish the technical and economic feasibility of using hot brine resources for electric power production and other industrial applications. Phase 0 includes the conceptual design of an experimental test-bed facility and a 10-MWe power generating facility.

  1. Porosity Evolution in a Creeping Single Crystal (Preprint)

    DTIC Science & Technology

    2012-08-01

    1] indicated that the growth of initially present processing induced voids in a nickel based single crystal superalloy played a significant role in...processing induced voids in a nickel based single crystal superalloy played a significant role in limiting creep life. Also, creep tests on single...experimental observations of creep deformation and failure of a nickel based single crystal superalloy, [1, 2]. Metallographic observations have shown that Ni

  2. Waterhammer Transient Simulation and Model Anchoring for the Robotic Lunar Lander Propulsion System

    NASA Technical Reports Server (NTRS)

    Stein, William B.; Trinh, Huu P.; Reynolds, Michael E.; Sharp, David J.

    2011-01-01

    Waterhammer transients have the potential to adversely impact propulsion system design if not properly addressed. Waterhammer can potentially lead to system plumbing, and component damage. Multi-thruster propulsion systems also develop constructive/destructive wave interference which becomes difficult to predict without detailed models. Therefore, it is important to sufficiently characterize propulsion system waterhammer in order to develop a robust design with minimal impact to other systems. A risk reduction activity was performed at Marshall Space Flight Center to develop a tool for estimating waterhammer through the use of anchored simulation for the Robotic Lunar Lander (RLL) propulsion system design. Testing was performed to simulate waterhammer surges due to rapid valve closure and consisted of twenty-two series of waterhammer tests, resulting in more than 300 valve actuations. These tests were performed using different valve actuation schemes and three system pressures. Data from the valve characterization tests were used to anchor the models that employed MSCSoftware.EASY5 v.2010 to model transient fluid phenomena by using transient forms of mass and energy conservation. The anchoring process was performed by comparing initial model results to experimental data and then iterating the model input to match the simulation results with the experimental data. The models provide good correlation with experimental results, supporting the use of EASY5 as a tool to model fluid transients and provide a baseline for future RLL system modeling. This paper addresses tasks performed during the waterhammer risk reduction activity for the RLL propulsion system. The problem of waterhammer simulation anchoring as applied to the RLL system is discussed with results from the corresponding experimental valve tests. Important factors for waterhammer mitigation are discussed along with potential design impacts to the RLL propulsion system.

  3. Electrodermal complexity during the Stroop colour word test.

    PubMed

    Svetlak, Miroslav; Bob, Petr; Cernik, Michal; Kukleta, Miloslav

    2010-01-15

    Several recent studies suggest that quantitative description of signal complexity using algorithms of nonlinear analysis could uncover new information about the autonomic system that is not reflected using common methods applied to measures of autonomic activity. With this aim we have performed complexity analysis of electrodermal activity (EDA) assessed in 106 healthy university students during rest conditions and non-conflicting and conflicting Stroop task. Complexity analysis applied to EDA was performed using Skinner's algorithm for pointwise correlation dimension (PD2). Results have shown that EDA responses during the Stroop Colour Word test are related to significantly increased or decreased complexity. Particularly significant result is that PD2 has a unique ability to predict to an extent the change in EDA response to stress i.e. that subjects with low initial PD2 tended to respond to experimental stress by its increase and subjects with high initial PD2 values tended to respond by its decrease. This response was not found in EDA measures where increase of the EDA presented predominant response to experimental stress in majority of the subjects. These findings suggest that PD2 is more sensitive to subtle aspects of functionally and spatially distributed modulatory influences of various parts of the brain that are involved in the EDA modulation and provides novel information in comparison to traditional methods.

  4. A Novel Method to Simulate the Progression of Collagen Degeneration of Cartilage in the Knee: Data from the Osteoarthritis Initiative

    NASA Astrophysics Data System (ADS)

    Mononen, Mika E.; Tanska, Petri; Isaksson, Hanna; Korhonen, Rami K.

    2016-02-01

    We present a novel algorithm combined with computational modeling to simulate the development of knee osteoarthritis. The degeneration algorithm was based on excessive and cumulatively accumulated stresses within knee joint cartilage during physiological gait loading. In the algorithm, the collagen network stiffness of cartilage was reduced iteratively if excessive maximum principal stresses were observed. The developed algorithm was tested and validated against experimental baseline and 4-year follow-up Kellgren-Lawrence grades, indicating different levels of cartilage degeneration at the tibiofemoral contact region. Test groups consisted of normal weight and obese subjects with the same gender and similar age and height without osteoarthritic changes. The algorithm accurately simulated cartilage degeneration as compared to the Kellgren-Lawrence findings in the subject group with excess weight, while the healthy subject group’s joint remained intact. Furthermore, the developed algorithm followed the experimentally found trend of cartilage degeneration in the obese group (R2 = 0.95, p < 0.05 experiments vs. model), in which the rapid degeneration immediately after initiation of osteoarthritis (0-2 years, p < 0.001) was followed by a slow or negligible degeneration (2-4 years, p > 0.05). The proposed algorithm revealed a great potential to objectively simulate the progression of knee osteoarthritis.

  5. Onsite 40-kilowatt fuel cell power plant manufacturing and field test program

    NASA Technical Reports Server (NTRS)

    1985-01-01

    A joint Gas Research Institute and U.S. Department of Energy Program was initiated in 1982 to evaluate the use of fuel cell power systems for on-site energy service. Forty-six 40 kW fuel cell power plants were manufactured at the United Technologies Corporation facility in South Windsor, Connecticut, and are being delivered to host utilities and other program participants in the United States and Japan for field testing. The construction of the 46 fully-integrated power plants was completed in January 1985 within the constraints of the contract plan. The program has provided significant experience in the manufacture, acceptance testing, deployment, and support of on-site fuel cell systems. Initial field test results also show that these experimental power plants meet the performance and environmental requirements of a commercial specification. This Interim Report encompasses the design and manufacturing phases of the 40 kW Power Plant Manufacturing and Field Test program. The contract between UTC and NASA also provides UTC field engineering support to the host utilities, training programs and associated manuals for utility operating and maintenance personnel, spare parts support for a defined test period, and testing at UTC of a power plant made available from a preceding program phase. These activities are ongoing and will be reported subsequently.

  6. Finite plate thickness effects on the Rayleigh-Taylor instability in elastic-plastic materials

    NASA Astrophysics Data System (ADS)

    Polavarapu, Rinosh; Banerjee, Arindam

    2017-11-01

    The majority of theoretical studies have tackled the Rayleigh-Taylor instability (RTI) problem in solids using an infinitely thick plate. Recent theoretical studies by Piriz et al. (PRE 95, 053108, 2017) have explored finite thickness effects. We seek to validate this recent theoretical estimate experimentally using our rotating wheel RTI experiment in an accelerated elastic-plastic material. The test section consists of a container filled with air and mayonnaise (a non-Newtonian emulsion) with an initial perturbation between two materials. The plate thickness effects are studied by varying the depth of the soft-solid. A set of experiments is run by employing different initial conditions with different container dimensions. Additionally, the effect of acceleration rate (driving pressure rise time) on the instability threshold with reference to the finite thickness will also be inspected. Furthermore, the experimental results are compared to the analytical strength models related to finite thickness effects on RTI. Authors acknowledge financial support from DOE-SSAA Grant # DE-NA0003195 and LANL subcontract #370333.

  7. Integrating evolutionary and functional approaches to infer adaptation at specific loci.

    PubMed

    Storz, Jay F; Wheat, Christopher W

    2010-09-01

    Inferences about adaptation at specific loci are often exclusively based on the static analysis of DNA sequence variation. Ideally,population-genetic evidence for positive selection serves as a stepping-off point for experimental studies to elucidate the functional significance of the putatively adaptive variation. We argue that inferences about adaptation at specific loci are best achieved by integrating the indirect, retrospective insights provided by population-genetic analyses with the more direct, mechanistic insights provided by functional experiments. Integrative studies of adaptive genetic variation may sometimes be motivated by experimental insights into molecular function, which then provide the impetus to perform population genetic tests to evaluate whether the functional variation is of adaptive significance. In other cases, studies may be initiated by genome scans of DNA variation to identify candidate loci for recent adaptation. Results of such analyses can then motivate experimental efforts to test whether the identified candidate loci do in fact contribute to functional variation in some fitness-related phenotype. Functional studies can provide corroborative evidence for positive selection at particular loci, and can potentially reveal specific molecular mechanisms of adaptation.

  8. Acute effects of whole-body cryotherapy on sit-and-reach amplitude in women and men.

    PubMed

    De Nardi, Massimo; La Torre, Antonio; Benis, Roberto; Sarabon, Nejc; Fonda, Borut

    2015-12-01

    Flexibility is an intrinsic property of body tissues, which among other factors determines the range of motion (ROM). A decrease in neural activation of the muscle has been linked with greater ROM. Cryotherapy is an effective technique to reduces neural activation. Hence, the aim of the present study was to evaluate if a single session of whole-body cryotherapy (WBC) affects ROM. 60 women and 60 men were divided into two groups (control and experimental). After the initial sit-and-reach test, experimental group performed a 150 s session of WBC, whereas the control group stayed in thermo-neutral environment. Immediately after, both groups performed another sit-and-reach test. A 3-way analysis of variance revealed statistically significant time×group and time × gender interaction. Experimental groups improved sit-and-reach amplitude to a greater extend than the control group. Our results support the hypothesis that ROM is increased immediately after a single session of WBC. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Experimental and Numerical Analysis of Notched Composites Under Tension Loading

    NASA Astrophysics Data System (ADS)

    Aidi, Bilel; Case, Scott W.

    2015-12-01

    Experimental quasi-static tests were performed on center notched carbon fiber reinforced polymer (CFRP) composites having different stacking sequences made of G40-600/5245C prepreg. The three-dimensional Digital Image Correlation (DIC) technique was used during quasi-static tests conducted on quasi-isotropic notched samples to obtain the distribution of strains as a function of applied stress. A finite element model was built within Abaqus to predict the notched strength and the strain profiles for comparison with measured results. A user-material subroutine using the multi-continuum theory (MCT) as a failure initiation criterion and an energy-based damage evolution law as implemented by Autodesk Simulation Composite Analysis (ASCA) was used to conduct a quantitative comparison of strain components predicted by the analysis and obtained in the experiments. Good agreement between experimental data and numerical analyses results are observed. Modal analysis was carried out to investigate the effect of static damage on the dominant frequencies of the notched structure using the resulted degraded material elements. The first in-plane mode was found to be a good candidate for tracking the level of damage.

  10. Modelling mass transfer during venting/soil vapour extraction: Non-aqueous phase liquid/gas mass transfer coefficient estimation

    NASA Astrophysics Data System (ADS)

    Esrael, D.; Kacem, M.; Benadda, B.

    2017-07-01

    We investigate how the simulation of the venting/soil vapour extraction (SVE) process is affected by the mass transfer coefficient, using a model comprising five partial differential equations describing gas flow and mass conservation of phases and including an expression accounting for soil saturation conditions. In doing so, we test five previously reported quations for estimating the non-aqueous phase liquid (NAPL)/gas initial mass transfer coefficient and evaluate an expression that uses a reference NAPL saturation. Four venting/SVE experiments utilizing a sand column are performed with dry and non-saturated sand at low and high flow rates, and the obtained experimental results are subsequently simulated, revealing that hydrodynamic dispersion cannot be neglected in the estimation of the mass transfer coefficient, particularly in the case of low velocities. Among the tested models, only the analytical solution of a convection-dispersion equation and the equation proposed herein are suitable for correctly modelling the experimental results, with the developed model representing the best choice for correctly simulating the experimental results and the tailing part of the extracted gas concentration curve.

  11. Test program to provide confidence in liquid oxygen cooling of hydrocarbon fueled rocket thrust chambers

    NASA Technical Reports Server (NTRS)

    Armstrong, E. S.

    1986-01-01

    An experimental program has been planned at the NASA Lewis Research Center to build confidence in the feasibility of liquid oxygen cooling for hydrocarbon fueled rocket engines. Although liquid oxygen cooling has previously been incorporated in test hardware, more runtime is necessary to gain confidence in this concept. In the previous tests, small oxygen leaks developed at the throat of the thrust chamber and film cooled the hot-gas side of the chamber wall without resulting in catastrophic failure. However, more testing is necessary to demonstrate that a catastrophic failure would not occur if cracks developed further upstream between the injector and the throat, where the boundary layer has not been established. Since under normal conditions cracks are expected to form in the throat region of the thrust chamber, cracks must be initiated artificially in order to control their location. Several methods of crack initiation are discussed in this report. Four thrust chambers, three with cracks and one without, should be tested. The axial location of the cracks should be varied parametrically. Each chamber should be instrumented to determine the effects of the cracks, as well as the overall performance and durability of the chambers.

  12. Thermal modeling of W rod armor.

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

    Nygren, Richard Einar

    2004-09-01

    Sandia has developed and tested mockups armored with W rods over the last decade and pioneered the initial development of W rod armor for International Thermonuclear Experimental Reactor (ITER) in the 1990's. We have also developed 2D and 3D thermal and stress models of W rod-armored plasma facing components (PFCs) and test mockups and are applying the models to both short pulses, i.e. edge localized modes (ELMs), and thermal performance in steady state for applications in C-MOD, DiMES testing and ITER. This paper briefly describes the 2D and 3D models and their applications with emphasis on modeling for an ongoingmore » test program that simulates repeated heat loads from ITER ELMs.« less

  13. Test-Free Fracture Toughness

    NASA Technical Reports Server (NTRS)

    Minnetyan, Levon; Chamis, Christos C. (Technical Monitor)

    2003-01-01

    Computational simulation results can give the prediction of damage growth and progression and fracture toughness of composite structures. The experimental data from literature provide environmental effects on the fracture behavior of metallic or fiber composite structures. However, the traditional experimental methods to analyze the influence of the imposed conditions are expensive and time consuming. This research used the CODSTRAN code to model the temperature effects, scaling effects and the loading effects of fiber/braided composite specimens with and without fiber-optic sensors on the damage initiation and energy release rates. The load-displacement relationship and fracture toughness assessment approach is compared with the test results from literature and it is verified that the computational simulation, with the use of established material modeling and finite element modules, adequately tracks the changes of fracture toughness and subsequent fracture propagation for any fiber/braided composite structure due to the change of fiber orientations, presence of large diameter optical fibers, and any loading conditions.

  14. Test-Free Fracture Toughness

    NASA Technical Reports Server (NTRS)

    Minnetyan, Levon; Chamis, Christos C. (Technical Monitor)

    2003-01-01

    Computational simulation results can give the prediction of damage growth and progression and fracture toughness of composite structures. The experimental data from literature provide environmental effects on the fracture behavior of metallic or fiber composite structures. However, the traditional experimental methods to analyze the influence of the imposed conditions are expensive and time consuming. This research used the CODSTRAN code to model the temperature effects, scaling effects and the loading effects of fiberbraided composite specimens with and without fiber-optic sensors on the damage initiation and energy release rates. The load-displacement relationship and fracture toughness assessment approach is compared with the test results from literature and it is verified that the computational simulation, with the use of established material modeling and finite element modules, adequately tracks the changes of fracture toughness and subsequent fracture propagation for any fiberbraided composite structure due to the change of fiber orientations, presence of large diameter optical fibers, and any loading conditions.

  15. Large strain dynamic compression for soft materials using a direct impact experiment

    NASA Astrophysics Data System (ADS)

    Meenken, T.; Hiermaier, S.

    2006-08-01

    Measurement of strain rate dependent material data of low density low strength materials like polymeric foams and rubbers still poses challenges of a different kind to the experimental set up. For instance, in conventional Split Hopkinson Pressure Bar tests the impedance mismatch between the bars and the specimen makes strain measurement almost impossible. Application of viscoelastic bars poses new problems with wave dispersion. Also, maximum achievable strains and strain rates depend directly on the bar lengths, resulting in large experimental set ups in order to measure relevant data for automobile crash applications. In this paper a modified SHPB will be presented for testing low impedance materials. High strains can be achieved with nearly constant strain rate. A thin film stress measurement has been applied to the specimen/bar interfaces to investigate the initial sample ring up process. The process of stress homogeneity within the sample was investigated on EPDM and PU rubber.

  16. Profile of Students’ Mental Model Change on Law Concepts Archimedes as Impact of Multi-Representation Approach

    NASA Astrophysics Data System (ADS)

    Taher, M.; Hamidah, I.; Suwarma, I. R.

    2017-09-01

    This paper outlined the results of an experimental study on the effects of multi-representation approach in learning Archimedes Law on students’ mental model improvement. The multi-representation techniques implemented in the study were verbal, pictorial, mathematical, and graphical representations. Students’ mental model was classified into three levels, i.e. scientific, synthetic, and initial levels, based on the students’ level of understanding. The present study employed the pre-experimental methodology, using one group pretest-posttest design. The subject of the study was 32 eleventh grade students in a Public Senior High School in Riau Province. The research instrument included model mental test on hydrostatic pressure concept, in the form of essay test judged by experts. The findings showed that there was positive change in students’ mental model, indicating that multi-representation approach was effective to improve students’ mental model.

  17. Outcomes of Trauma-Informed Interventions for Incarcerated Women.

    PubMed

    King, Erin A

    2017-05-01

    The purpose of this article was to conduct a review of experimental, quasi-experimental, and pre-test/post-test studies using manualized, trauma-informed interventions with incarcerated women. A systematic search of electronic databases, reference harvesting, and communication with experts were used to identify relevant primary studies. Nine studies meeting the specified inclusion/exclusion criteria were identified. Three studies used random assignment and five used a comparison or waitlist group. Interventions identified included Seeking Safety, Helping Women Recover/Beyond Trauma, Esuba, and Beyond Violence. Results of the studies indicate a decrease in post-traumatic stress disorder (PTSD) symptomatology and an additive effect to treatment as usual. Initial evidence for trauma-informed interventions for incarcerated women appears positive; however, replication using more rigorous research designs and inclusion of effect sizes are recommended. Limitations of this review include exclusion of the gray literature and lack of meta-analysis.

  18. Prospects for a Muon Spin Resonance Facility in the MuCool Test Area

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

    Johnstone, John A.

    2017-04-12

    This paper investigates the feasibility of re-purposing the MuCool Test Area beamline and experimental hall to support a Muon Spin Resonance facility, which would make it the only such facility in the US. This report reviews the basic muon production concepts studied and operationally implemented at TRIUMF, PSI, and RAL and their application to the MTA facility. Two scenarios were determined feasible. One represents an initial minimal-shielding and capital-cost investment stage with a single secondary muon beamline that transports the primary beam to an existing high-intensity beam absorber located outside of the hall. Another, upgraded stage, involves an optimized productionmore » target pile and high-intensity absorber installed inside the experimental hall and potentially multiple secondary muon lines. In either scenario, with attention to target design, the MTA can host enabling and competitive Muon Spin Resonance experiments« less

  19. Experimental Waterflow Determination of the Dynamic Hydraulic Transfer Function for the J-2X Oxidizer Turbopump. Part Two; Results and Interpretation

    NASA Technical Reports Server (NTRS)

    Zoladz, Tom; Patel, Sandeep; Lee, Erik; Karon, Dave

    2011-01-01

    Experimental results describing the hydraulic dynamic pump transfer matrix (Yp) for a cavitating J-2X oxidizer turbopump inducer+impeller tested in subscale waterflow are presented. The transfer function is required for integrated vehicle pogo stability analysis as well as optimization of local inducer pumping stability. Dynamic transfer functions across widely varying pump hydrodynamic inlet conditions are extracted from measured data in conjunction with 1D-model based corrections. Derived Dynamic transfer functions are initially interpreted relative to traditional Pogo pump equations. Water-to-liquid oxygen scaling of measured cavitation characteristics are discussed. Comparison of key dynamic transfer matrix terms derived from waterflow testing are made with those implemented in preliminary Ares Upper Stage Pogo stability modeling. Alternate cavitating pump hydraulic dynamic equations are suggested which better reflect frequency dependencies of measured transfer matrices.

  20. Dissociative chemisorption of methane on metal surfaces: Tests of dynamical assumptions using quantum models and ab initio molecular dynamics

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

    Jackson, Bret, E-mail: jackson@chem.umass.edu; Nattino, Francesco; Kroes, Geert-Jan

    The dissociative chemisorption of methane on metal surfaces is of great practical and fundamental importance. Not only is it the rate-limiting step in the steam reforming of natural gas, the reaction exhibits interesting mode-selective behavior and a strong dependence on the temperature of the metal. We present a quantum model for this reaction on Ni(100) and Ni(111) surfaces based on the reaction path Hamiltonian. The dissociative sticking probabilities computed using this model agree well with available experimental data with regard to variation with incident energy, substrate temperature, and the vibrational state of the incident molecule. We significantly expand the vibrationalmore » basis set relative to earlier studies, which allows reaction probabilities to be calculated for doubly excited initial vibrational states, though it does not lead to appreciable changes in the reaction probabilities for singly excited initial states. Sudden models used to treat the center of mass motion parallel to the surface are compared with results from ab initio molecular dynamics and found to be reasonable. Similar comparisons for molecular rotation suggest that our rotationally adiabatic model is incorrect, and that sudden behavior is closer to reality. Such a model is proposed and tested. A model for predicting mode-selective behavior is tested, with mixed results, though we find it is consistent with experimental studies of normal vs. total (kinetic) energy scaling. Models for energy transfer into lattice vibrations are also examined.« less

  1. Flow and fracture behavior of aluminum alloy 6082-T6 at different tensile strain rates and triaxialities.

    PubMed

    Chen, Xuanzhen; Peng, Yong; Peng, Shan; Yao, Song; Chen, Chao; Xu, Ping

    2017-01-01

    This study aims to investigate the flow and fracture behavior of aluminum alloy 6082-T6 (AA6082-T6) at different strain rates and triaxialities. Two groups of Charpy impact tests were carried out to further investigate its dynamic impact fracture property. A series of tensile tests and numerical simulations based on finite element analysis (FEA) were performed. Experimental data on smooth specimens under various strain rates ranging from 0.0001~3400 s-1 shows that AA6082-T6 is rather insensitive to strain rates in general. However, clear rate sensitivity was observed in the range of 0.001~1 s-1 while such a characteristic is counteracted by the adiabatic heating of specimens under high strain rates. A Johnson-Cook constitutive model was proposed based on tensile tests at different strain rates. In this study, the average stress triaxiality and equivalent plastic strain at facture obtained from numerical simulations were used for the calibration of J-C fracture model. Both of the J-C constitutive model and fracture model were employed in numerical simulations and the results was compared with experimental results. The calibrated J-C fracture model exhibits higher accuracy than the J-C fracture model obtained by the common method in predicting the fracture behavior of AA6082-T6. Finally, the Scanning Electron Microscope (SEM) of fractured specimens with different initial stress triaxialities were analyzed. The magnified fractographs indicate that high initial stress triaxiality likely results in dimple fracture.

  2. The influence of the compression interface on the failure behavior and size effect of concrete

    NASA Astrophysics Data System (ADS)

    Kampmann, Raphael

    The failure behavior of concrete materials is not completely understood because conventional test methods fail to assess the material response independent of the sample size and shape. To study the influence of strength and strain affecting test conditions, four typical concrete sample types were experimentally evaluated in uniaxial compression and analyzed for strength, deformational behavior, crack initiation/propagation, and fracture patterns under varying boundary conditions. Both low friction and conventional compression interfaces were assessed. High-speed video technology was used to monitor macrocracking. Inferential data analysis proved reliably lower strength results for reduced surface friction at the compression interfaces, regardless of sample shape. Reciprocal comparisons revealed statistically significant strength differences between most sample shapes. Crack initiation and propagation was found to differ for dissimilar compression interfaces. The principal stress and strain distributions were analyzed, and the strain domain was found to resemble the experimental results, whereas the stress analysis failed to explain failure for reduced end confinement. Neither stresses nor strains indicated strength reductions due to reduced friction, and therefore, buckling effects were considered. The high-speed video analysis revealed localize buckling phenomena, regardless of end confinement. Slender elements were the result of low friction, and stocky fragments developed under conventional confinement. The critical buckling load increased accordingly. The research showed that current test methods do not reflect the "true'' compressive strength and that concrete failure is strain driven. Ultimate collapse results from buckling preceded by unstable cracking.

  3. Experimental investigation of internal short circuits in lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Poramapojana, Poowanart

    With outstanding performance of Lithium-ion batteries, they have been widely used in many applications. For hybrid electric vehicles and electric vehicles, customer concerns of battery safety have been raised as a number of car accidents were reported. To evaluate safety performance of these batteries, a nail penetration test is used to simulate and induce internal short circuits instantaneously. Efforts to explain failure mechanisms of the penetration using electrochemical-thermal coupled models have been proposed. However, there is no experimental validation because researchers lack of a diagnostic tool to acquire important cell characteristics at a shorting location, such as shorting current and temperature. In this present work, diagnostic nails have been developed to acquire nail center temperatures and shorting current flow through the nails during nail penetration tests. Two types of cylindrical wall structures are used to construct the nails: a double-layered stainless steel wall and a composite cylindrical wall. An inner hollow cylinder functions as a sensor holder where two wires and one thermocouple are installed. To study experimental reproducibility and repeatability of experimental results, two nail penetration tests are conducted using two diagnostic nails with the double-layered wall. Experimental data shows that the shorting resistance at the initial stage is a critical parameter to obtain repeatable results. The average shorting current for both tests is approximately 40 C-rate. The fluctuation of the shorting current is due to random sparks and fire caused loose contacts between the nail and the cell components. Moreover, comparative experimental results between the two wall structures reveal that the wall structure does not affect the cell characteristics and Ohmic heat generation of the nail. The wall structure effects to current measurements inside the nail. With the composite wall, the actual current redistribution into the inner wall is found to be a sinusoidal waveform.

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

    Lincoln, D.E.

    Preliminary analysis of two populations of Artemisia tridentata compared leaf chemical and physiological characteristics which influence herbivores. The proportion of sixteen of the volatile compounds differed significantly between the two populations; however, total yield of volatiles did not. This initial survey established the reliability of the procedure to quantitatively monitor plant responses to CO/sub 2/ enrichment and suggests that test samples be restricted to a single population. Four sesquiterpene lactones have been selected for the experimental quantitative HPLC analysis; all peaks have been assigned identities and have demonstrated high degree of reproducibility. Growth of Artemisia under high and low lightmore » at three CO/sub 2/ levels demonstrated that this species also undergoes a ''dilution'' of the leaf carbon content and is useful as test species for herbivory response to CO/sub 2/ induced effects. The initial experiment also showed that high irradiance is a necessary growth condition. 10 refs.« less

  5. Sodium Based Heat Pipe Modules for Space Reactor Concepts: Stainless Steel SAFE-100 Core

    NASA Technical Reports Server (NTRS)

    Martin, James J.; Reid, Robert S.

    2004-01-01

    A heat pipe cooled reactor is one of several candidate reactor cores being considered for advanced space power and propulsion systems to support future space exploration applications. Long life heat pipe modules, with designs verified through a combination of theoretical analysis and experimental lifetime evaluations, would be necessary to establish the viability of any of these candidates, including the heat pipe reactor option. A hardware-based program was initiated to establish the infrastructure necessary to build heat pipe modules. This effort, initiated by Los Alamos National Laboratory and referred to as the Safe Affordable Fission Engine (SAFE) project, set out to fabricate and perform non-nuclear testing on a modular heat pipe reactor prototype that can provide 100 kilowatt from the core to an energy conversion system at 700 C. Prototypic heat pipe hardware was designed, fabricated, filled, closed-out and acceptance tested.

  6. Simplified approach to the mixed time-averaging semiclassical initial value representation for the calculation of dense vibrational spectra

    NASA Astrophysics Data System (ADS)

    Buchholz, Max; Grossmann, Frank; Ceotto, Michele

    2018-03-01

    We present and test an approximate method for the semiclassical calculation of vibrational spectra. The approach is based on the mixed time-averaging semiclassical initial value representation method, which is simplified to a form that contains a filter to remove contributions from approximately harmonic environmental degrees of freedom. This filter comes at no additional numerical cost, and it has no negative effect on the accuracy of peaks from the anharmonic system of interest. The method is successfully tested for a model Hamiltonian and then applied to the study of the frequency shift of iodine in a krypton matrix. Using a hierarchic model with up to 108 normal modes included in the calculation, we show how the dynamical interaction between iodine and krypton yields results for the lowest excited iodine peaks that reproduce experimental findings to a high degree of accuracy.

  7. An enhancement to the NA4 gear vibration diagnostic parameter

    NASA Technical Reports Server (NTRS)

    Decker, Harry J.; Handschuh, Robert F.; Zakrajsek, James J.

    1994-01-01

    A new vibration diagnostic parameter for health monitoring of gears, NA4*, is proposed and tested. A recently developed gear vibration diagnostic parameter NA4 outperformed other fault detection methods at indicating the start and initial progression of damage. However, in some cases, as the damage progressed, the sensitivity of the NA4 and FM4 parameters tended to decrease and no longer indicated damage. A new parameter, NA4* was developed by enhancing NA4 to improve the trending of the parameter. This allows for the indication of damage both at initiation and also as the damage progresses. The NA4* parameter was verified and compared to the NA4 and FM4 parameters using experimental data from single mesh spur and spiral bevel gear fatigue rigs. The primary failure mode for the test cases was naturally occurring tooth surface pitting. The NA4* parameter is shown to be a more robust indicator of damage.

  8. Design of a high-throughput human neural crest cell migration assay to indicate potential developmental toxicants.

    PubMed

    Nyffeler, Johanna; Karreman, Christiaan; Leisner, Heidrun; Kim, Yong Jun; Lee, Gabsang; Waldmann, Tanja; Leist, Marcel

    2017-01-01

    Migration of neural crest cells (NCCs) is one of the pivotal processes of human fetal development. Malformations arise if NCC migration and differentiation are impaired genetically or by toxicants. In the currently available test systems for migration inhibition of NCC (MINC), the manual generation of a cell-free space results in extreme operator dependencies, and limits throughput. Here a new test format was established. The assay avoids scratching by plating cells around a commercially available circular stopper. Removal of the stopper barrier after cell attachment initiates migration. This microwell-based circular migration zone NCC function assay (cMINC) was further optimized for toxicological testing of human pluripotent stem cell (hPSC)-derived NCCs. The challenge of obtaining data on viability and migration by automated image processing was addressed by developing a freeware. Data on cell proliferation were obtained by labelling replicating cells, and by careful assessment of cell viability for each experimental sample. The role of cell proliferation as an experimental confounder was tested experimentally by performing the cMINC in the presence of the proliferation-inhibiting drug cytosine arabinoside (AraC), and by a careful evaluation of mitotic events over time. Data from these studies led to an adaptation of the test protocol, so that toxicant exposure was limited to 24 h. Under these conditions, a prediction model was developed that allows classification of toxicants as either inactive, leading to unspecific cytotoxicity, or specifically inhibiting NC migration at non-cytotoxic concentrations.

  9. Effect of Electron Seeding on Experimentally Measured Multipactor Discharge Threshold

    NASA Astrophysics Data System (ADS)

    Noland, Jonathan; Graves, Timothy; Lemon, Colby; Looper, Mark; Farkas, Alex

    2012-10-01

    Multipactor is a vacuum phenomenon in which electrons, moving in resonance with an externally applied electric field, impact material surfaces. If the number of secondary electrons created per primary electron impact averages more than unity, the resonant interaction can lead to an electron avalanche. Multipactor is a generally undesirable phenomenon, as it can cause local heating, absorb power, or cause detuning of RF circuits. In order to increase the probability of multipactor initiation, test facilities often employ various seeding sources such as radioactive sources (Cesium 137, Strontium 90), electron guns, or photon sources. Even with these sources, the voltage for multipactor initiation is not certain as parameters such as material type, RF pulse length, and device wall thickness can all affect seed electron flux and energy in critical gap regions, and hence the measured voltage threshold. This study investigates the effects of seed electron source type (e.g., photons versus beta particles), material type, gap size, and RF pulse length variation on multipactor threshold. In addition to the experimental work, GEANT4 simulations will be used to estimate the production rate of low energy electrons (< 5 keV) by high energy electrons and photons. A comparison of the experimental fluxes to the typical energetic photon and particle fluxes experienced by spacecraft in various orbits will also be made. Initial results indicate that for a simple, parallel plate device made of aluminum, there is no threshold variation (with seed electrons versus with no seed electrons) under continuous-wave RF exposure.

  10. Automatic detection of multiple UXO-like targets using magnetic anomaly inversion and self-adaptive fuzzy c-means clustering

    NASA Astrophysics Data System (ADS)

    Yin, Gang; Zhang, Yingtang; Fan, Hongbo; Ren, Guoquan; Li, Zhining

    2017-12-01

    We have developed a method for automatically detecting UXO-like targets based on magnetic anomaly inversion and self-adaptive fuzzy c-means clustering. Magnetic anomaly inversion methods are used to estimate the initial locations of multiple UXO-like sources. Although these initial locations have some errors with respect to the real positions, they form dense clouds around the actual positions of the magnetic sources. Then we use the self-adaptive fuzzy c-means clustering algorithm to cluster these initial locations. The estimated number of cluster centroids represents the number of targets and the cluster centroids are regarded as the locations of magnetic targets. Effectiveness of the method has been demonstrated using synthetic datasets. Computational results show that the proposed method can be applied to the case of several UXO-like targets that are randomly scattered within in a confined, shallow subsurface, volume. A field test was carried out to test the validity of the proposed method and the experimental results show that the prearranged magnets can be detected unambiguously and located precisely.

  11. Modeling the atomistic growth behavior of gold nanoparticles in solution

    NASA Astrophysics Data System (ADS)

    Turner, C. Heath; Lei, Yu; Bao, Yuping

    2016-04-01

    The properties of gold nanoparticles strongly depend on their three-dimensional atomic structure, leading to an increased emphasis on controlling and predicting nanoparticle structural evolution during the synthesis process. In order to provide this atomistic-level insight and establish a link to the experimentally-observed growth behavior, a kinetic Monte Carlo simulation (KMC) approach is developed for capturing Au nanoparticle growth characteristics. The advantage of this approach is that, compared to traditional molecular dynamics simulations, the atomistic nanoparticle structural evolution can be tracked on time scales that approach the actual experiments. This has enabled several different comparisons against experimental benchmarks, and it has helped transition the KMC simulations from a hypothetical toy model into a more experimentally-relevant test-bed. The model is initially parameterized by performing a series of automated comparisons of Au nanoparticle growth curves versus the experimental observations, and then the refined model allows for detailed structural analysis of the nanoparticle growth behavior. Although the Au nanoparticles are roughly spherical, the maximum/minimum dimensions deviate from the average by approximately 12.5%, which is consistent with the corresponding experiments. Also, a surface texture analysis highlights the changes in the surface structure as a function of time. While the nanoparticles show similar surface structures throughout the growth process, there can be some significant differences during the initial growth at different synthesis conditions.

  12. Multi Resolution In-Situ Testing and Multiscale Simulation for Creep Fatigue Damage Analysis of Alloy 617

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

    Liu, Yongming; Oskay, Caglar

    This report outlines the research activities that were carried out for the integrated experimental and simulation investigation of creep-fatigue damage mechanism and life prediction of Nickel-based alloy, Inconel 617 at high temperatures (950° and 850°). First, a novel experimental design using a hybrid control technique is proposed. The newly developed experimental technique can generate different combinations of creep and fatigue damage by changing the experimental design parameters. Next, detailed imaging analysis and statistical data analysis are performed to quantify the failure mechanisms of the creep fatigue of alloy 617 at high temperatures. It is observed that the creep damage ismore » directly associated with the internal voids at the grain boundaries and the fatigue damage is directly related to the surface cracking. It is also observed that the classical time fraction approach does not has a good correlation with the experimental observed damage features. An effective time fraction parameter is seen to have an excellent correlation with the material microstructural damage. Thus, a new empirical damage interaction diagram is proposed based on the experimental observations. Following this, a macro level viscoplastic model coupled with damage is developed to simulate the stress/strain response under creep fatigue loadings. A damage rate function based on the hysteresis energy and creep energy is proposed to capture the softening behavior of the material and a good correlation with life prediction and material hysteresis behavior is observed. The simulation work is extended to include the microstructural heterogeneity. A crystal plasticity finite element model considering isothermal and large deformation conditions at the microstructural scale has been developed for fatigue, creep-fatigue as well as creep deformation and rupture at high temperature. The model considers collective dislocation glide and climb of the grains and progressive damage accumulation of the grain boundaries. The glide model incorporates a slip resistance evolution model that characterizes the solute-drag creep effects and can capture well the stress-strain and stress time response of fatigue and creep-fatigue tests at various strain ranges and hold times. In order to accurately capture the creep strains that accumulate particularly at relatively low stress levels, a dislocation climb model has been incorporated into the crystal plasticity modeling framework. The dislocation climb model parameters are calibrated and verified through experimental creep tests performed at 950°. In addition, a cohesive zone model has been fully implemented in the context of the crystal plasticity finite element model to capture the intergranular creep damage. The parameters of the cohesive zone model have been calibrated using available experimental data. The numerical simulations illustrate the capability of the proposed model in capturing damage initiation and growth under creep loads as compared to the experimental observations. The microscale analysis sheds light on the crack initiation sites and propagation patterns within the microstructure. The model is also utilized to investigate the hybrid-controlled creep-fatigue tests and has been found to capture reasonably well the stress-strain response with different hold times and hold stress magnitudes.« less

  13. Experimentally Observed Electrical Durability of 4H-SiC JFET ICs Operating from 500 C to 700 C

    NASA Technical Reports Server (NTRS)

    Neudeck, Philip G.; Spry, David J.; Chen, Liangyu; Lukco, Dorothy; Chang, Carl W.; Beheim, Glenn M.

    2016-01-01

    Prolonged 500 degrees Celsius to 700 degrees Celsius electrical testing data from 4H-SiC junction field effect transistor (JFET) integrated circuits (ICs) are combined with post-testing microscopic studies in order to gain more comprehensive understanding of the durability limits of the present version of NASA Glenn's extreme temperature microelectronics technology. The results of this study support the hypothesis that T = 500 degrees Celsius durability-limiting IC failure initiates with thermal-stress-related crack formation where dielectric passivation layers overcoat micron-scale vertical features including patterned metal traces.

  14. Steady-state and transient operation of a heat-pipe radiator system

    NASA Technical Reports Server (NTRS)

    Sellers, J. P.

    1974-01-01

    Data obtained on a VCHP heat-pipe radiator system tested in a vacuum environment were studied. Analyses and interpretation of the steady-state results are presented along with an initial analysis of some of the transient data. Particular emphasis was placed on quantitative comparisons of the experimental data with computer model simulations. The results of the study provide a better understanding of the system but do not provide a complete explanation for the observed low VCHP performance and the relatively flat radiator panel temperature distribution. The results of the study also suggest hardware, software, and testing improvements.

  15. Analysis of the OPERA 15-pin experiment with SABRE-2P. [LMFBR

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

    Rose, S.D.; Carbajo, J.J.

    The OPERA (Out-of-Pile Expulsion and Reentry Apparatus) experiment simulates the initial phase of a pump coastdown without scram of a liquid-metal fast breeder reactor, specifically the Fast Flux Test Facility. The test section is a 15-pin 60/sup 0/ triangular sector designed to simulate a full-size 61-pin hexagonal bundle. A previous study indicates this to be an adequate simulation. In this paper, experimental results from the OPERA 15-pin experiment performed at ANL in 1982 are compared to analytical calculations obtained with the SABRE-2P code at ORNL.

  16. Develop and test fuel cell powered on-site integrated total energy system. Phase 3: Full-scale power plant development

    NASA Technical Reports Server (NTRS)

    Kaufman, A.

    1981-01-01

    An integrated 5 kW power system based upon methanol fuel and a phosphoric acid fuel cell operating at about 473 K is described. Description includes test results of advanced fuel cell catalysts, a semiautomatic acid replenishment system and a completed 5 kW methanol/system reformer. The results of a preliminary system test on a reformer/stack/inverter combination are reported. An initial design for a 25 kW stack is presented. Experimental plans are outlined for data acquisition necessary for design of a 50 kW methanol/steam reformer. Activities related to complete mathematical modelling of the integrated power system, including wasteheat utilization, are described.

  17. Evaluation of the Susceptibility to SCC Initiation of Alloy 690 in Simulated PWR Primary Water

    NASA Astrophysics Data System (ADS)

    Tsutsumi, Kazuya; Couvant, Thierry

    Alloy 690 has been widely used in fabricating components of LWR plants as an alternative material to Alloy 600 which has exhibited a significant susceptibility to PWSCC. However, some authors have reported that Alloy 690 can suffer a significant susceptibility to SCC crack growth when highly cold worked. While most of the recent studies emphasize SCC propagation phase, EDF and its partners are focusing on the material's resistance to SCC initiation. This paper summarizes the current work carried out at EDF MAI on the SCC initiation. By means of constant elongation rate tests (CERTs) and constant displacement tests, experimental investigation of the susceptibility to PWSCC were performed. No SCC was observed on either an extruded bar or on two plates, even after 24%-1D cold rolling, confirming the superior PWSCC resistance of Alloy 690 independent of a amount of intergranular precipitation of carbides, and also revealing that such cold rolling does not necessarily decrease the resistance to SCC. On the other hand, a experimental steam generator tube that has a degraded microstructure due to specific heat-treatment revealed its susceptibility to SCC, probably because of the interactive effect of microstructure with heavy intragranular carbide precipitations and the cold worked superficial layer. This phenomenon is in good agreement with results previously published. In this study, the maximal crack depth slightly increased when DH increased from 5 to 60 cc.kg-1H2O. No significant prior ageing effect on the crack depth was observed, even when ageing was combined with high DH.

  18. Qualification of CASMO5 / SIMULATE-3K against the SPERT-III E-core cold start-up experiments

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

    Grandi, G.; Moberg, L.

    SIMULATE-3K is a three-dimensional kinetic code applicable to LWR Reactivity Initiated Accidents. S3K has been used to calculate several international recognized benchmarks. However, the feedback models in the benchmark exercises are different from the feedback models that SIMULATE-3K uses for LWR reactors. For this reason, it is worth comparing the SIMULATE-3K capabilities for Reactivity Initiated Accidents against kinetic experiments. The Special Power Excursion Reactor Test III was a pressurized-water, nuclear-research facility constructed to analyze the reactor kinetic behavior under initial conditions similar to those of commercial LWRs. The SPERT III E-core resembles a PWR in terms of fuel type, moderator,more » coolant flow rate, and system pressure. The initial test conditions (power, core flow, system pressure, core inlet temperature) are representative of cold start-up, hot start-up, hot standby, and hot full power. The qualification of S3K against the SPERT III E-core measurements is an ongoing work at Studsvik. In this paper, the results for the 30 cold start-up tests are presented. The results show good agreement with the experiments for the reactivity initiated accident main parameters: peak power, energy release and compensated reactivity. Predicted and measured peak powers differ at most by 13%. Measured and predicted reactivity compensations at the time of the peak power differ less than 0.01 $. Predicted and measured energy release differ at most by 13%. All differences are within the experimental uncertainty. (authors)« less

  19. Experimental and Numerical Analysis of Triaxially Braided Composites Utilizing a Modified Subcell Modeling Approach

    NASA Technical Reports Server (NTRS)

    Cater, Christopher; Xiao, Xinran; Goldberg, Robert K.; Kohlman, Lee W.

    2015-01-01

    A combined experimental and analytical approach was performed for characterizing and modeling triaxially braided composites with a modified subcell modeling strategy. Tensile coupon tests were conducted on a [0deg/60deg/-60deg] braided composite at angles of 0deg, 30deg, 45deg, 60deg and 90deg relative to the axial tow of the braid. It was found that measured coupon strength varied significantly with the angle of the applied load and each coupon direction exhibited unique final failures. The subcell modeling approach implemented into the finite element software LS-DYNA was used to simulate the various tensile coupon test angles. The modeling approach was successful in predicting both the coupon strength and reported failure mode for the 0deg, 30deg and 60deg loading directions. The model over-predicted the strength in the 90deg direction; however, the experimental results show a strong influence of free edge effects on damage initiation and failure. In the absence of these local free edge effects, the subcell modeling approach showed promise as a viable and computationally efficient analysis tool for triaxially braided composite structures. Future work will focus on validation of the approach for predicting the impact response of the braided composite against flat panel impact tests.

  20. Experimental and Numerical Analysis of Triaxially Braided Composites Utilizing a Modified Subcell Modeling Approach

    NASA Technical Reports Server (NTRS)

    Cater, Christopher; Xiao, Xinran; Goldberg, Robert K.; Kohlman, Lee W.

    2015-01-01

    A combined experimental and analytical approach was performed for characterizing and modeling triaxially braided composites with a modified subcell modeling strategy. Tensile coupon tests were conducted on a [0deg/60deg/-60deg] braided composite at angles [0deg, 30deg, 45deg, 60deg and 90deg] relative to the axial tow of the braid. It was found that measured coupon strength varied significantly with the angle of the applied load and each coupon direction exhibited unique final failures. The subcell modeling approach implemented into the finite element software LS-DYNA was used to simulate the various tensile coupon test angles. The modeling approach was successful in predicting both the coupon strength and reported failure mode for the 0deg, 30deg and 60deg loading directions. The model over-predicted the strength in the 90deg direction; however, the experimental results show a strong influence of free edge effects on damage initiation and failure. In the absence of these local free edge effects, the subcell modeling approach showed promise as a viable and computationally efficient analysis tool for triaxially braided composite structures. Future work will focus on validation of the approach for predicting the impact response of the braided composite against flat panel impact tests.

  1. USE OF TRANS-CONTEXTUAL MODEL-BASED PHYSICAL ACTIVITY COURSE IN DEVELOPING LEISURE-TIME PHYSICAL ACTIVITY BEHAVIOR OF UNIVERSITY STUDENTS.

    PubMed

    Müftüler, Mine; İnce, Mustafa Levent

    2015-08-01

    This study examined how a physical activity course based on the Trans-Contextual Model affected the variables of perceived autonomy support, autonomous motivation, determinants of leisure-time physical activity behavior, basic psychological needs satisfaction, and leisure-time physical activity behaviors. The participants were 70 Turkish university students (M age=23.3 yr., SD=3.2). A pre-test-post-test control group design was constructed. Initially, the participants were randomly assigned into an experimental (n=35) and a control (n=35) group. The experimental group followed a 12 wk. trans-contextual model-based intervention. The participants were pre- and post-tested in terms of Trans-Contextual Model constructs and of self-reported leisure-time physical activity behaviors. Multivariate analyses showed significant increases over the 12 wk. period for perceived autonomy support from instructor and peers, autonomous motivation in leisure-time physical activity setting, positive intention and perceived behavioral control over leisure-time physical activity behavior, more fulfillment of psychological needs, and more engagement in leisure-time physical activity behavior in the experimental group. These results indicated that the intervention was effective in developing leisure-time physical activity and indicated that the Trans-Contextual Model is a useful way to conceptualize these relationships.

  2. Multiple Restart Testing of a Stainless Steel Sodium Heat Pipe Module

    NASA Technical Reports Server (NTRS)

    Martin, James; Mireles, Omar; Reid, Robert

    2005-01-01

    A heat pipe cooled reactor is one of several candidate reactor cores being considered for space power and propulsion systems to support future space exploration activities. Long life heat pipe modules. with designs verified through a combination of theoretical analysis and experimental evaluations. would be necessary to establish the viability of this option. A hardware-based program was initiated to begin experimental testing of components to verify compliance of proposed designs. To this end, a number of stainless steel/sodium heat pipe modules have been designed and fabricated to support experimental testing of a Safe Affordable Fission Engine (SAFE) project, a 100-kWt core design pursued jointly by the Marshall Space Flight Center and the Los Alamos National Laboratory. One of the SAFE heat pipe modules was successfully subjected to over 200 restarts. examining the behavior of multiple passive freeze/thaw operations. Typical operation included a 1-hour startup to an average evaporator temperature of 1000 K followed by a 15 minute hold at temperature. Nominal maximum input power during the hold period was 1.9 kW. Between heating cycles the module was cooled to less than 325 K, returning the sodium to a frozen state in preparation fop the next startup cycle.

  3. Development of multilayer perceptron networks for isothermal time temperature transformation prediction of U-Mo-X alloys

    NASA Astrophysics Data System (ADS)

    Johns, Jesse M.; Burkes, Douglas

    2017-07-01

    In this work, a multilayered perceptron (MLP) network is used to develop predictive isothermal time-temperature-transformation (TTT) models covering a range of U-Mo binary and ternary alloys. The selected ternary alloys for model development are U-Mo-Ru, U-Mo-Nb, U-Mo-Zr, U-Mo-Cr, and U-Mo-Re. These model's ability to predict 'novel' U-Mo alloys is shown quite well despite the discrepancies between literature sources for similar alloys which likely arise from different thermal-mechanical processing conditions. These models are developed with the primary purpose of informing experimental decisions. Additional experimental insight is necessary in order to reduce the number of experiments required to isolate ideal alloys. These models allow test planners to evaluate areas of experimental interest; once initial tests are conducted, the model can be updated and further improve follow-on testing decisions. The model also improves analysis capabilities by reducing the number of data points necessary from any particular test. For example, if one or two isotherms are measured during a test, the model can construct the rest of the TTT curve over a wide range of temperature and time. This modeling capability reduces the cost of experiments while also improving the value of the results from the tests. The reduced costs could result in improved material characterization and therefore improved fundamental understanding of TTT dynamics. As additional understanding of phenomena driving TTTs is acquired, this type of MLP model can be used to populate unknowns (such as material impurity and other thermal mechanical properties) from past literature sources.

  4. Evaluating the contributions of task expectancy in the testing and guessing benefits on recognition memory.

    PubMed

    Huff, Mark J; Yates, Tyler J; Balota, David A

    2018-05-03

    Recently, we have shown that two types of initial testing (recall of a list or guessing of critical items repeated over 12 study/test cycles) improved final recognition of related and unrelated word lists relative to restudy. These benefits were eliminated, however, when test instructions were manipulated within subjects and presented after study of each list, procedures designed to minimise expectancy of a specific type of upcoming test [Huff, Balota, & Hutchison, 2016. The costs and benefits of testing and guessing on recognition memory. Journal of Experimental Psychology: Learning, Memory, and Cognition, 42, 1559-1572. doi: 10.1037/xlm0000269 ], suggesting that testing and guessing effects may be influenced by encoding strategies specific for the type of upcoming task. We follow-up these experiments by examining test-expectancy processes in guessing and testing. Testing and guessing benefits over restudy were not found when test instructions were presented either after (Experiment 1) or before (Experiment 2) a single study/task cycle was completed, nor were benefits found when instructions were presented before study/task cycles and the task was repeated three times (Experiment 3). Testing and guessing benefits emerged only when instructions were presented before a study/task cycle and the task was repeated six times (Experiments 4A and 4B). These experiments demonstrate that initial testing and guessing can produce memory benefits in recognition, but only following substantial task repetitions which likely promote task-expectancy processes.

  5. A complete dosimetry experimental program in support to the core characterization and to the power calibration of the CABRI reactor. A complete dosimetry experimental program in support of the core characterization and of the power calibration of the CABRI reactor

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

    Rodiac, F.; Hudelot, JP.; Lecerf, J.

    CABRI is an experimental pulse reactor operated by CEA at the Cadarache research center. Since 1978 the experimental programs have aimed at studying the fuel behavior under Reactivity Initiated Accident (RIA) conditions. Since 2003, it has been refurbished in order to be able to provide RIA and LOCA (Loss Of Coolant Accident) experiments in prototypical PWR conditions (155 bar, 300 deg. C). This project is part of a broader scope including an overall facility refurbishment and a safety review. The global modification is conducted by the CEA project team. It is funded by IRSN, which is conducting the CIP experimentalmore » program, in the framework of the OECD/NEA project CIP. It is financed in the framework of an international collaboration. During the reactor restart, commissioning tests are realized for all equipment, systems and circuits of the reactor. In particular neutronics and power commissioning tests will be performed respectively in 2015 and 2016. This paper focuses on the design of a complete and original dosimetry program that was built in support to the CABRI core characterization and to the power calibration. Each one of the above experimental goals will be fully described, as well as the target uncertainties and the forecasted experimental techniques and data treatment. (authors)« less

  6. Double torsion fracture mechanics testing of shales under chemically reactive conditions

    NASA Astrophysics Data System (ADS)

    Chen, X.; Callahan, O. A.; Holder, J. T.; Olson, J. E.; Eichhubl, P.

    2015-12-01

    Fracture properties of shales is vital for applications such as shale and tight gas development, and seal performance of carbon storage reservoirs. We analyze the fracture behavior from samples of Marcellus, Woodford, and Mancos shales using double-torsion (DT) load relaxation fracture tests. The DT test allows the determination of mode-I fracture toughness (KIC), subcritical crack growth index (SCI), and the stress-intensity factor vs crack velocity (K-V) curves. Samples are tested at ambient air and aqueous conditions with variable ionic concentrations of NaCl and CaCl2, and temperatures up to 70 to determine the effects of chemical/environmental conditions on fracture. Under ambient air condition, KIC determined from DT tests is 1.51±0.32, 0.85±0.25, 1.08±0.17 MPam1/2 for Marcellus, Woodford, and Mancos shales, respectively. Tests under water showed considerable change of KIC compared to ambient condition, with 10.6% increase for Marcellus, 36.5% decrease for Woodford, and 6.7% decrease for Mancos shales. SCI under ambient air condition is between 56 and 80 for the shales tested. The presence of water results in a significant reduction of the SCI from 70% to 85% compared to air condition. Tests under chemically reactive solutions are currently being performed with temperature control. K-V curves under ambient air conditions are linear with stable SCI throughout the load-relaxation period. However, tests conducted under water result in an initial cracking period with SCI values comparable to ambient air tests, which then gradually transition into stable but significantly lower SCI values of 10-20. The non-linear K-V curves reveal that crack propagation in shales is initially limited by the transport of chemical agents due to their low permeability. Only after the initial cracking do interactions at the crack tip lead to cracking controlled by faster stress corrosion reactions. The decrease of SCI in water indicates higher crack propagation velocity due to faster stress corrosion rate in water than in ambient air. The experimental results are applicable for the prediction of fracture initiation based on KIC, modeling fracture pattern based on SCI, and the estimation of dynamic fracture propagation such as crack growth velocity and crack re-initiation.

  7. Initiation and growth of multiple-site damage in the riveted lap joint of a curved stiffened fuselage panel: An experimental and analytical study

    NASA Astrophysics Data System (ADS)

    Ahmed, Abubaker Ali

    As part of the structural integrity research of the National Aging Aircraft Research Program, a comprehensive study on multiple-site damage (MSD) initiation and growth in a pristine lap-joint fuselage panel has been conducted. The curved stiffened fuselage panel was tested at the Full-Scale Aircraft Structural Test Evaluation and Research (FASTER) facility located at the Federal Aviation Administration William J. Hughes Technical Center. A strain survey test was conducted to verify proper load application. The panel was then subjected to a fatigue test with constant-amplitude cyclic loading. The applied loading spectrum included underload marker cycles so that crack growth history could be reconstructed from post-test fractographic examinations. Crack formation and growth were monitored via nondestructive and high-magnification visual inspections. Strain gage measurements recorded during the strain survey tests indicated that the inner surface of the skin along the upper rivet row of the lap joint experienced high tensile stresses due to local bending. During the fatigue loading, cracks were detected by eddy-current inspections at multiple rivet holes along the upper rivet row. Through-thickness cracks were detected visually after about 80% of the fatigue life. Once MSD cracks from two adjacent rivet holes linked up, there was a quick deterioration in the structural integrity of the lap joint. The linkup resulted in a 2.87" (72.9-mm) lead fatigue crack that rapidly propagated across 12 rivet holes and crossed over into the next skin bay, at which stage the fatigue test was terminated. A post-fatigue residual strength test was then conducted by loading the panel quasi-statically up to final failure. The panel failed catastrophically when the crack extended instantaneously across three additional bays. Post-test fractographic examinations of the fracture surfaces in the lap joint of the fuselage panel were conducted to characterize subsurface crack initiation and growth. Results showed evidence of fretting damage and crack initiation at multiple locations near the rivet holes along the faying surface of the skin. The subsurface cracks grew significantly along the faying surface before reaching the outer surface of the skin, forming elliptical crack fronts. A finite element model (FE) of the panel was constructed and geometrically-nonlinear analyses conducted to determine strain distribution under the applied loads. The FE model was validated by comparing the analysis results with the strain gage measurements recorded during the strain survey test. The validated FE model was then used to determine stress-intensity factors at the crack tips. Stress-intensity factor results indicated that crack growth in the lap joint was under mixed-mode; however, the opening-mode stress intensity factor was dominant. The stress-intensity factors computed from the FE analysis were used to conduct cycle-by-cycle integration of fatigue crack growth. In the cycle-by-cycle integration, the NASGRO crack growth model was used with its parameters selected to account for the effects of plasticity-induced crack closure and the test environment on crack growth rate. Fatigue crack growth predictions from cycle-by-cycle computation were in good agreement with the experimental measured crack growth data. The results of the study provide key insights into the natural development and growth of MSD cracks in the pristine lap joint. The data provided by the study represent a valuable source for the evaluation and validation of analytical methodologies used for predicting MSD crack initiation and growth.

  8. Effect of initial contact surface condition on the friction and wear properties of bearing steel in cyclic reciprocating sliding contact

    NASA Astrophysics Data System (ADS)

    Tanaka, Y.; Endo, M.; Moriyama, S.

    2017-05-01

    Delamination failure is one of the most important engineering problems. This failure can frequently be detrimental to rolling contact machine elements such as bearings, gear wheels, etc. This phenomenon, called rolling contact fatigue, has a close relationship not only with opening-mode but also with shear-mode fatigue crack growth. The crack face interference is known to significantly affect the shear-mode fatigue crack propagation and its threshold behavior. Quantitative investigation on friction and wear at fatigue crack faces in the material is essentially impossible. Previously, thus, a novel ring-on-ring test by making use of fatigue testing machine was proposed to simulate a cyclic reciprocating sliding contact of crack surfaces. However, this test procedure had some problems. For instance, in order to achieve the uniform contact at the start of test, the rubbing of specimens must be conducted in advance. By this treatment, the specimen surfaces were already damaged before the test. In this study, an improvement of experimental method was made to perform the test using the damage-free specimens. The friction and wear properties for heat-treated high carbon-chromium bearing steel were investigated with this new method and the results were compared to the results obtained by using the initially damaged specimens.

  9. Experimental Study of the Roles of Mechanical and Hydrologic Properties in the Initiation of Natural Hydraulic Fractures

    NASA Astrophysics Data System (ADS)

    French, M. E.; Goodwin, L. B.; Boutt, D. F.; Lilydahl, H.

    2008-12-01

    Natural hydraulic fractures (NHFs) are inferred to form where pore fluid pressure exceeds the least compressive stress; i.e., where the hydraulic fracture criterion is met. Although it has been shown that mechanical heterogeneities serve as nuclei for NHFs, the relative roles of mechanical anisotropy and hydrologic properties in initiating NHFs in porous granular media have not been fully explored. We designed an experimental protocol that produces a pore fluid pressure high enough to exceed the hydraulic fracture criterion, allowing us to initiate NHFs in the laboratory. Initially, cylindrical samples 13 cm long and 5 cm in diameter are saturated, σ1 is radial, and σ3 is axial. By dropping the end load (σ3) and pore fluid pressure simultaneously at the end caps, we produce a large pore fluid pressure gradient parallel to the long axis of the sample. This allows us to meet the hydraulic fracture criterion without separating the sample from its end caps. The time over which the pore fluid remains elevated is a function of hydraulic diffusivity. An initial test with a low diffusivity sandstone produced NHFs parallel to bedding laminae that were optimally oriented for failure. To evaluate the relative importance of mechanical heterogeneities such as bedding versus hydraulic properties, we are currently investigating variably cemented St. Peter sandstone. This quartz arenite exhibits a wide range of primary structures, from well developed bedding laminae to locally massive sandstone. Diagenesis has locally accentuated these structures, causing degree of cementation to vary with bedding, and the sandstone locally exhibits concretions that form elliptical rather than tabular heterogeneities. Bulk permeability varies from k=10-12 m2 to k=10-15 m2 and porosity varies from 5% to 28% in this suite of samples. Variations in a single sample are smaller, with permeability varying no more than an order of magnitude within a single core. Air minipermeameter and tracer tests document this variability at the cm scale. Experiments will be performed with σ3 and the pore pressure gradient both perpendicular and parallel to sub-cm scale bedding. The results of these tests will be compared to those of structurally homogeneous samples and samples with elliptical heterogeneities.

  10. A randomized controlled trial of an intervention program to Brazilian mothers who use corporal punishment.

    PubMed

    Santini, Paolla Magioni; Williams, Lucia C A

    2017-09-01

    This study evaluated a positive parenting program to Brazilian mothers who used corporal punishment with their children. The intervention was conducted in four agencies serving vulnerable children, and at a home replica laboratory at the University. Mothers who admitted using corporal punishment were randomly assigned between experimental (n=20) and control group (n=20). The program consisted of 12 individual sessions using one unit from Projeto Parceria (Partnership Project), with specific guidelines and materials on positive parenting, followed by observational sessions of mother-child interaction with live coaching and a video feedback session in the lab. The study used an equivalent group experimental design with pre/post-test and follow-up, in randomized controlled trials. Measures involved: Initial Interview; Strengths and Difficulties Questionnaire (SDQ) - parent and child versions; Beck Depression Inventory (BDI); observational sessions with a protocol; and a Program Evaluation by participants. Analysis of mixed models for repeated measures revealed significant positive effects on the BDI and SDQ total scores, as well as less Conduct problems and Hyperactivity in SDQ measures from the experimental group mothers, comparing pre with post-test. Observational data also indicated significant improvement in positive interaction from the experimental group mothers at post-test, in comparison with controls. No significant results were found, however, in children's observational measures. Limitations of the study involved using a restricted sample, among others. Implications for future research are suggested. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Convenience experimentation.

    PubMed

    Krohs, Ulrich

    2012-03-01

    Systems biology aims at explaining life processes by means of detailed models of molecular networks, mainly on the whole-cell scale. The whole cell perspective distinguishes the new field of systems biology from earlier approaches within molecular cell biology. The shift was made possible by the high throughput methods that were developed for gathering 'omic' (genomic, proteomic, etc.) data. These new techniques are made commercially available as semi-automatic analytic equipment, ready-made analytic kits and probe arrays. There is a whole industry of supplies for what may be called convenience experimentation. My paper inquires some epistemic consequences of strong reliance on convenience experimentation in systems biology. In times when experimentation was automated to a lesser degree, modeling and in part even experimentation could be understood fairly well as either being driven by hypotheses, and thus proceed by the testing of hypothesis, or as being performed in an exploratory mode, intended to sharpen concepts or initially vague phenomena. In systems biology, the situation is dramatically different. Data collection became so easy (though not cheap) that experimentation is, to a high degree, driven by convenience equipment, and model building is driven by the vast amount of data that is produced by convenience experimentation. This results in a shift in the mode of science. The paper shows that convenience driven science is not primarily hypothesis-testing, nor is it in an exploratory mode. It rather proceeds in a gathering mode. This shift demands another shift in the mode of evaluation, which now becomes an exploratory endeavor, in response to the superabundance of gathered data. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. Foreign Language Competence and Content and Language Integrated Learning in Multilingual Schools in Catalonia: An "Ex Post Facto" Study Analysing the Results of State Key Competences Testing

    ERIC Educational Resources Information Center

    Coral, Josep; Lleixà, Teresa; Ventura, Carles

    2018-01-01

    The member states of the European Union have funded many initiatives supporting the teaching and learning of foreign languages. Content and language integrated learning is one of the experimental language programmes that have been introduced in Catalonia, in the north-east of Spain. The aims of this study are to analyse the results achieved by…

  13. Two-Phase Working Fluids for the Temperature Range 50 to 350 C

    NASA Technical Reports Server (NTRS)

    Saaski, E. W.; Owzarski, P. C.

    1977-01-01

    The decomposition and corrosion of two-phase heat transfer liquids and metal envelopes have been investigated on the basis of molecular bond strengths and chemical thermodynamics. Potentially stable heat transfer fluids for the temperature range 100 C to 350 C have been identified, and reflux heat pipes tests initiated with 10 fluids and carbon steel and aluminum envelopes to experimentally establish corrosion behavior and noncondensable gas generation rates.

  14. Quiet Clean Short-haul Experimental Engine (QCSEE) Under-The-Wing (UTW) boiler plate nacelle and core exhaust nozzle design report

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The mechanical design of the boiler plate nacelle and core exhaust nozzle for the QCSEE under the wing engine is presented. The nacelle, which features interchangeable hard-wall and acoustic panels, is to be utilized in the initial engine testing to establish acoustic requirements for the subsequent composite nacelle as well as in the QCSEE over the wing engine configuration.

  15. Pion and proton showers in the CALICE scintillator-steel analogue hadron calorimeter

    NASA Astrophysics Data System (ADS)

    Bilki, B.; Repond, J.; Xia, L.; Eigen, G.; Thomson, M. A.; Ward, D. R.; Benchekroun, D.; Hoummada, A.; Khoulaki, Y.; Chang, S.; Khan, A.; Kim, D. H.; Kong, D. J.; Oh, Y. D.; Blazey, G. C.; Dyshkant, A.; Francis, K.; Lima, J. G. R.; Salcido, R.; Zutshi, V.; Salvatore, F.; Kawagoe, K.; Miyazaki, Y.; Sudo, Y.; Suehara, T.; Tomita, T.; Ueno, H.; Yoshioka, T.; Apostolakis, J.; Dannheim, D.; Folger, G.; Ivantchenko, V.; Klempt, W.; Lucaci-Timoce, A.-I.; Ribon, A.; Schlatter, D.; Sicking, E.; Uzhinskiy, V.; Giraud, J.; Grondin, D.; Hostachy, J.-Y.; Morin, L.; Brianne, E.; Cornett, U.; David, D.; Ebrahimi, A.; Falley, G.; Gadow, K.; Göttlicher, P.; Günter, C.; Hartbrich, O.; Hermberg, B.; Karstensen, S.; Krivan, F.; Krüger, K.; Lu, S.; Lutz, B.; Morozov, S.; Morgunov, V.; Neubüser, C.; Reinecke, M.; Sefkow, F.; Smirnov, P.; Tran, H. L.; Buhmann, P.; Garutti, E.; Laurien, S.; Matysek, M.; Ramilli, M.; Briggl, K.; Eckert, P.; Harion, T.; Munwes, Y.; Schultz-Coulon, H.-Ch.; Shen, W.; Stamen, R.; Norbeck, E.; Northacker, D.; Onel, Y.; van Doren, B.; Wilson, G. W.; Wing, M.; Combaret, C.; Caponetto, L.; Eté, R.; Grenier, G.; Han, R.; Ianigro, J. C.; Kieffer, R.; Laktineh, I.; Lumb, N.; Mathez, H.; Mirabito, L.; Petrukhin, A.; Steen, A.; Berenguer Antequera, J.; Calvo Alamillo, E.; Fouz, M.-C.; Marin, J.; Puerta-Pelayo, J.; Verdugo, A.; Corriveau, F.; Bobchenko, B.; Chistov, R.; Chadeeva, M.; Danilov, M.; Drutskoy, A.; Epifantsev, A.; Markin, O.; Mironov, D.; Mizuk, R.; Novikov, E.; Rusinov, V.; Tarkovsky, E.; Besson, D.; Buzhan, P.; Ilyin, A.; Popova, E.; Gabriel, M.; Kiesling, C.; van der Kolk, N.; Simon, F.; Soldner, C.; Szalay, M.; Tesar, M.; Weuste, L.; Amjad, M. S.; Bonis, J.; Callier, S.; Conforti di Lorenzo, S.; Cornebise, P.; Dulucq, F.; Fleury, J.; Frisson, T.; Martin-Chassard, G.; Pöschl, R.; Raux, L.; Richard, F.; Rouëné, J.; Seguin-Moreau, N.; de la Taille, Ch.; Anduze, M.; Boudry, V.; Brient, J.-C.; Clerc, C.; Cornat, R.; Frotin, M.; Gastaldi, F.; Matthieu, A.; Mora de Freitas, P.; Musat, G.; Ruan, M.; Videau, H.; Zacek, J.; Cvach, J.; Gallus, P.; Havranek, M.; Janata, M.; Kvasnicka, J.; Lednicky, D.; Marcisovsky, M.; Polak, I.; Popule, J.; Tomasek, L.; Tomasek, M.; Sicho, P.; Smolik, J.; Vrba, V.; Zalesak, J.; Jeans, D.; Weber, S.

    2015-04-01

    Showers produced by positive hadrons in the highly granular CALICE scintillator-steel analogue hadron calorimeter were studied. The experimental data were collected at CERN and FNAL for single particles with initial momenta from 10 to 80 GeV/c. The calorimeter response and resolution and spatial characteristics of shower development for proton- and pion-induced showers for test beam data and simulations using GEANT4 version 9.6 are compared.

  16. Bridging the Gap: Linking Simulation and Testing

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

    Krajewski, Paul E.; Carsley, John; Stoudt, Mark R.

    2012-09-01

    The Materials Genome Initiative (MGI) which is a key enabler for the Advanced Manufacturing Partnership, announced in 2011 by U.S. President Barack Obama, was established to accelerate the development and deployment of advanced materials. The MGI is driven by the need to "bridge the gap" between (I) experimental results and computational analysis to enable the rapid development and validation of new mateirals, and (II) the processes required to convert these materials into useable goods.

  17. Neurofibromatosis and Schwannomatosis.

    PubMed

    Plotkin, Scott R; Wick, Antje

    2018-02-01

    Neurofibromatosis 1, neurofibromatosis 2, and schwannomatosis are a group of related classically inherited but often times sporadic tumor suppressor syndromes. Neuro-oncologists should recognize these syndromes, initiate necessary tests in patients with a clinical suspicion, and support genetic counseling of patients and families. In this review, clinical presentation, diagnostic criteria, day-to-day management including supportive care as well as updates on genetics, and experimental treatment strategies are discussed. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  18. Prevention and Treatment of Noise-Induced Tinnitus

    DTIC Science & Technology

    2012-07-01

    process of completing the normative data base(s) of VGLUT1 , VAT and VGAT immunostaining in the rat AVCN and DCN that will allow assessment of changes under...our experimental conditions. Initial results indicate some loss of VGLUT1 immunolabeled auditory nerve terminals in the ventral cochlear nucleus...Research Accomplishments for TASK 3: Test the hypothesis that the loss of AN terminals (marked by VGLUT1 immunolabel) on neurons in the AVCN and

  19. Analysis, testing, and evaluation of faulted and unfaulted Wye, Delta, and open Delta connected electromechanical actuators

    NASA Technical Reports Server (NTRS)

    Nehl, T. W.; Demerdash, N. A.

    1983-01-01

    Mathematical models capable of simulating the transient, steady state, and faulted performance characteristics of various brushless dc machine-PSA (power switching assembly) configurations were developed. These systems are intended for possible future use as primemovers in EMAs (electromechanical actuators) for flight control applications. These machine-PSA configurations include wye, delta, and open-delta connected systems. The research performed under this contract was initially broken down into the following six tasks: development of mathematical models for various machine-PSA configurations; experimental validation of the model for failure modes; experimental validation of the mathematical model for shorted turn-failure modes; tradeoff study; and documentation of results and methodology.

  20. Fulfilling the promise of the materials genome initiative with high-throughput experimental methodologies

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

    Green, Martin L.; Choi, C. L.; Hattrick-Simpers, J. R.

    The Materials Genome Initiative, a national effort to introduce new materials into the market faster and at lower cost, has made significant progress in computational simulation and modeling of materials. To build on this progress, a large amount of experimental data for validating these models, and informing more sophisticated ones, will be required. High-throughput experimentation generates large volumes of experimental data using combinatorial materials synthesis and rapid measurement techniques, making it an ideal experimental complement to bring the Materials Genome Initiative vision to fruition. This paper reviews the state-of-the-art results, opportunities, and challenges in high-throughput experimentation for materials design. Asmore » a result, a major conclusion is that an effort to deploy a federated network of high-throughput experimental (synthesis and characterization) tools, which are integrated with a modern materials data infrastructure, is needed.« less

  1. Fulfilling the promise of the materials genome initiative with high-throughput experimental methodologies

    DOE PAGES

    Green, Martin L.; Choi, C. L.; Hattrick-Simpers, J. R.; ...

    2017-03-28

    The Materials Genome Initiative, a national effort to introduce new materials into the market faster and at lower cost, has made significant progress in computational simulation and modeling of materials. To build on this progress, a large amount of experimental data for validating these models, and informing more sophisticated ones, will be required. High-throughput experimentation generates large volumes of experimental data using combinatorial materials synthesis and rapid measurement techniques, making it an ideal experimental complement to bring the Materials Genome Initiative vision to fruition. This paper reviews the state-of-the-art results, opportunities, and challenges in high-throughput experimentation for materials design. Asmore » a result, a major conclusion is that an effort to deploy a federated network of high-throughput experimental (synthesis and characterization) tools, which are integrated with a modern materials data infrastructure, is needed.« less

  2. Experimental performance of an ablative material as an external insulator for a hypersonic research aircraft

    NASA Technical Reports Server (NTRS)

    Puster, R. L.; Chapman, A. J.

    1977-01-01

    An ablative material composed of silica-filled elastomeric silicone was tested to evaluate its thermal and structural performance as an external insulator, or heat shield, for a hypersonic research aircraft. The material was also tested to determine whether it would form a durable char layer when initially heated and thereafter function primarily as an insulator with little further pyrolysis or char removal. Aerothermal tests were representative of nominal Mach 6 cruise conditions of the aircraft, and additional tests were representative of Mach 8 cruise and interference heating conditions. Radiant heating tests were used to simulate the complete nominal Mach 6 surface-temperature history. The silica char that formed during aerothermal tests was not durable. The char experienced a general and preferential surface recession, with the primary mechanism for char removal being erosion. Tests revealed that radiant heating is not a valid technique for simulating aerodynamic heating of the material.

  3. Durability testing at 5 atmospheres of advanced catalysts and catalyst supports for gas turbine engine combustors

    NASA Technical Reports Server (NTRS)

    Olson, B. A.; Lee, H. C.; Osgerby, I. T.; Heck, R. M.; Hess, H.

    1980-01-01

    The durability of CATCOM catalysts and catalyst supports was experimentally demonstrated in a combustion environment under simulated gas turbine engine combustor operating conditions. A test of 1000 hours duration was completed with one catalyst using no. 2 diesel fuel and operating at catalytically-supported thermal combustion conditions. The performance of the catalyst was determined by monitoring emissions throughout the test, and by examining the physical condition of the catalyst core at the conclusion of the test. Tests were performed periodically to determine changes in catalytic activity of the catalyst core. Detailed parametric studies were also run at the beginning and end of the durability test, using no. 2 fuel oil. Initial and final emissions for the 1000 hours test respectively were: unburned hydrocarbons (C3 vppm):0, 146, carbon monoxide (vppm):30, 2420; nitrogen oxides (vppm):5.7, 5.6.

  4. Planform curvature effects on flutter characteristics of a wing with 56 deg leading-edge sweep and panel aspect ratio of 1.14

    NASA Technical Reports Server (NTRS)

    Keller, Donald F.; Sandford, Maynard C.; Pinkerton, Theresa L.

    1991-01-01

    An experimental and analytical investigation was initiated to determine the effects of planform curvature (curving the leading and trailing edges of a wing in the X-Y plane) on the transonic flutter characteristics of a series of three moderately swept wing models. Experimental flutter results were obtained in the Langley Transonic Dynamics Tunnel for Mach numbers from 0.60-1.00, with air as the test medium. The models were semispan cantilevered wings with a 3 percent biconvex airfoil and a panel aspect ratio of 1.14. The baseline model had straight leading and trailing edges (i.e., no planform curvature). The radii of curvature of the leading edges for these two models were 200 and 80 inches. The radii of curvature of the leading edges of the other two models were determined so that the root and tip chords were identical for all three models. Experimental results showed that flutter-speed index and flutter frequency ratio increased as planform curvature increase (radius of curvature of the leading edge was decreased) over the test range of Mach numbers. Analytical flutter results were calculated with a subsonic flutter-prediction program, and they agreed well with the experimental results.

  5. Novel approach for beacon formation through simulated turbulence: initial lab-test results

    NASA Astrophysics Data System (ADS)

    Khizhnyak, A.; Markov, V.; Tomov, I.; Wu, F.

    2010-02-01

    In this paper we report the results of the analysis and experimental modeling of the target-in-the-loop (TIL) approach that is used to form a localized beacon for a laser beam propagating through turbulent atmosphere. The analogy between the TIL system and the laser cavity has been used here to simulate the process shaping the laser beacon on a remote image-resolved target with rough surface. The TIL breadboard was integrated and used for laboratory modeling of the proposed approach. This breadboard allowed to simulate the TIL arrangement with a rough-surface target and laser beam propagation through the turbulent atmospheric layer. Here we present the initial results of the performed studies.

  6. The protective effects of free wheel-running against cocaine psychomotor sensitization persist after exercise cessation in C57BL/6J mice.

    PubMed

    Lespine, L-F; Tirelli, E

    2015-12-03

    Previous literature suggests that free access to a running wheel can attenuate the behavioral responsiveness to addictive drugs in rodents. In a few studies, wheel-running cessation accentuated drug responsiveness. Here, we tested whether free wheel-running cessation is followed by (1) an accentuation or (2) an attenuation of cocaine psychomotor sensitization, knowing that no cessation of (continuous) wheel-running is associated with an attenuation of cocaine responsiveness. Male C57BL/6J mice, aged 35 days, were housed singly either with (exercising mice) or without (non-exercising mice) a running wheel. At the end of a period of 36 days, half of the exercising mice were deprived of their wheel whereas the other half of exercising mice kept their wheel until the end of experimentation (which lasted 85 days). The non-exercising mice were housed without wheel throughout experimentation. Testing took place 3 days after exercise cessation. After 2 once-daily drug-free test sessions, mice were tested for initiation of psychomotor sensitization over 13 once-daily injections of 8 mg/kg cocaine. Post-sensitization conditioned activation (saline challenge) and long-term expression of sensitization were assessed 2 or 30 days after the last sensitizing injection (same treatments as for initiation of sensitization), respectively. Exercising mice and mice undergoing wheel-running cessation exhibited comparable degrees of attenuation of all cocaine effects in comparison with the continuously non-exercising mice, which showed the greatest effects. Thus, the efficaciousness of wheel-running at attenuating cocaine sensitization not only resisted to exercise cessation but was also unambiguously persistent (an important effect rarely reported in previous literature). Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

  7. Evidence for deterministic chaos in aperiodic oscillations of acute lymphoblastic leukemia cells in long-term culture

    NASA Astrophysics Data System (ADS)

    Lambrou, George I.; Chatziioannou, Aristotelis; Vlahopoulos, Spiros; Moschovi, Maria; Chrousos, George P.

    Biological systems are dynamic and possess properties that depend on two key elements: initial conditions and the response of the system over time. Conceptualizing this on tumor models will influence conclusions drawn with regard to disease initiation and progression. Alterations in initial conditions dynamically reshape the properties of proliferating tumor cells. The present work aims to test the hypothesis of Wolfrom et al., that proliferation shows evidence for deterministic chaos in a manner such that subtle differences in the initial conditions give rise to non-linear response behavior of the system. Their hypothesis, tested on adherent Fao rat hepatoma cells, provides evidence that these cells manifest aperiodic oscillations in their proliferation rate. We have tested this hypothesis with some modifications to the proposed experimental setup. We have used the acute lymphoblastic leukemia cell line CCRF-CEM, as it provides an excellent substrate for modeling proliferation dynamics. Measurements were taken at time points varying from 24h to 48h, extending the assayed populations beyond that of previous published reports that dealt with the complex dynamic behavior of animal cell populations. We conducted flow cytometry studies to examine the apoptotic and necrotic rate of the system, as well as DNA content changes of the cells over time. The cells exhibited a proliferation rate of nonlinear nature, as this rate presented oscillatory behavior. The obtained data have been fit in known models of growth, such as logistic and Gompertzian growth.

  8. Effects of anisotropy and irradiation on the deformation behavior of Zircaloy 2. Final report

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

    Pelloux, R.M.; Ballinger, R.; Lucas, G.

    1979-01-01

    An experimental program investigated the effects of texture anisotropy and irradiation on the mechanical behavior of Zircaloy-2. Short time and time dependent mechanical behavior were considered. Irradiation effects were simulated through the use of 4.75 MeV protons. The temperature ranges investigated were 298/sup 0/K and 573 to 673/sup 0/K. Both cold worked-stress relieved and annealed material were used in this experimental program. Short time yield behavior of different crystallographic textures was determined by uniaxial and plane strain tests in the temperature range 298/sup 0/K and 573 to 673/sup 0/K. Monotonic flow loci were constructed for each texture. Yield behavior ismore » a strong function of the crystallographic texture number f at all temperatures investigated. The rotation of texture with increasing plastic strain was investigated as a function of initial texture at 298/sup 0/K and 623/sup 0/K. The rate of texture rotation df/epsilon/sub p/ was found to be a unique function of the initial texture for plastic strains less than 0.08. Time dependent mechanical behavior was investigated in the range 573 to 673/sup 0/K using constant load creep and stress relaxation tests. The tensile creep strength is proportional to the resolved fraction of basal poles in the test direction. In variable stress and temperature tests, the time-hardening rule was found to be inapplicable. The strain-hardening rule was applied with success to data obtained at temperatures less than or equal to 648/sup 0/K. Irradiation creep tests were conducted in vacuum at 598/sup 0/K and 102 to 241 MPa on 80..mu..m thick Zircaloy-2 foil specimens in both the recrystallized and cold worked-stress relieved condition. In the irradiation creep tests irradiation hardening and enhanced irradiation creep were observed. Radiation hardening effects were significant in annealed material but were attenuated in cold worked-stress relieved material.« less

  9. A microstructurally based model of solder joints under conditions of thermomechanical fatigue

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

    Frear, D.R.; Burchett, S.N.; Rashid, M.M.

    The thermomechanical fatigue failure of solder joints in increasingly becoming an important reliability issue. In this paper we present two computational methodologies that have been developed to predict the behavior of near eutectic Sn-Pb solder joints under fatigue conditions that are based on metallurgical tests as fundamental input for constitutive relations. The two-phase model mathematically predicts the heterogeneous coarsening behavior of near eutectic Sn-Pb solder. The finite element simulations from this model agree well with experimental thermomechanical fatigue tests. The simulations show that the presence of an initial heterogeneity in the solder microstructure could significantly degrade the fatigue lifetime. Themore » single phase model is a computational technique that was developed to predict solder joint behavior using materials data for constitutive relation constants that could be determined through straightforward metallurgical experiments. A shear/torsion test sample was developed to impose strain in two different orientations. Materials constants were derived from these tests and the results showed an adequate fit to experimental results. The single-phase model could be very useful for conditions where microstructural evolution is not a dominant factor in fatigue.« less

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

    PubMed

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

    2015-10-01

    The heavy application of pesticides and its potential effects on natural communities has attracted increasing attention to inadvertent impacts of these chemicals. Toxicologists conventionally use laboratory-based tests to assess lethal concentrations of pesticides. However, these tests often do not take into account indirect, interactive and long-term effects, and tend to ignore different rates of disintegration in the laboratory and under natural conditions. Our aim was to investigate the importance of the experimental venue for ecotoxicology tests. We reared tadpoles of the agile frog (Rana dalmatina) in the laboratory and in outdoor mesocosms and exposed them to three initial concentrations of a glyphosate-based herbicide (0, 2 and 6.5 mg a.e./L glyphosate), and to the presence or absence of caged predators (dragonfly larvae). The type of experimental venue had a large effect on the outcome: The herbicide was less lethal to tadpoles reared in outdoor mesocosms than in the laboratory. Further, while the herbicide had a negative effect on development time and on body mass in the laboratory, tadpoles exposed to the herbicide in mesocosms were larger at metamorphosis and developed faster in comparison to those reared in the absence of the herbicide. The effect of the herbicide on morphological traits of tadpoles also differed between the two venues. Finally, in the presence of the herbicide, tadpoles tended to be more active and to stay closer to the bottom of laboratory containers, while tadpole behaviour shifted in the opposite direction in outdoor mesocosms. Our results demonstrate major discrepancies between results of a classic laboratory-based ecotoxicity test and outcomes of an experiment performed in outdoor mesocosms. Consequently, the use of standard laboratory tests may have to be reconsidered and their benefits carefully weighed against the difficulties of performing experiments under more natural conditions. Tests validating experimentally estimated impacts of herbicides under natural conditions and studies identifying key factors determining the applicability of experimental results are urgently needed. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. The influence of lotteries on employees' workplace HIV testing behaviour.

    PubMed

    Weihs, Martin; Meyer-Weitz, Anna; Baasner-Weihs, Friederike

    2018-03-01

    The aim of the study was to understand how lottery incentives influenced the HIV counselling and testing (HCT) behaviour and behaviour intention of shop-floor workers who participated in a workplace HCT campaign initiative in two companies in the Nelson Mandela Bay municipality, South Africa. A post-test only quasi-experimental approach was used. The data were first collected, using a self-administered cross-sectional survey instrument, among the control group (n = 88) followed by the experimental group (n = 110) after the advent of HIV testing and lotteries was announced. HIV testing behaviour data were collected on the days of the HIV testing events. The theory of planned behaviour (TPB) was used as guiding theory. Principal component analysis (PCA), t- and chi-square tests, and logistic regression were conducted to analyse the data. A significant increase in the mean scores of the experimental as compared to the control condition for the subjective norm's construct (t = -3.55, p < 0.001) and HIV testing behaviour intention (χ 2 = 12.35, p < 0.001) was measured following the announcement of lottery incentives. The constructs of TPB explained 40% of the variance in HCT behaviour intention (R 2 = 0.40). The strongest predictor of behaviour intention was the subjective norm (B = 0.435 and p < 0.001), followed by the attitudinal component (B = 0.323 and p = 0.040). The announcement of lotteries made shop-floor workers develop a stronger intention to participate in workplace HIV testing through anticipation of stronger social support and encouragement. It was not possible to link behaviour intention to behaviour due to missing data. The findings point to the importance of providing workers with an opportunity to openly discuss HIV testing thus allowing mitigation of HIV stigma and discrimination and permitting HIV testing to become socially sanctioned and seen as part of a collective effort.

  12. Grainex Mar-M 247 Turbine Disk Life Study for NASA's High Temperature High Speed Turbine Seal Test Facility

    NASA Technical Reports Server (NTRS)

    Delgado, Irebert R.

    2015-01-01

    An experimental and analytical fatigue life study was performed on the Grainex Mar-M 247 disk used in NASA s Turbine Seal Test Facility. To preclude fatigue cracks from growing to critical size in the NASA disk bolt holes due to cyclic loading at severe test conditions, a retirement-for-cause methodology was adopted to detect and monitor cracks within the bolt holes using eddy-current inspection. For the NASA disk material that was tested, the fatigue strain-life to crack initiation at a total strain of 0.5 percent, a minimum to maximum strain ratio of 0, and a bolt hole temperature of 649 C was calculated to be 665 cycles using -99.95 percent prediction intervals. The fatigue crack propagation life was calculated to be 367 cycles after implementing a safety factor of 2 on life. Thus, the NASA disk bolt hole total life or retirement life was determined to be 1032 cycles at a crack depth of 0.501 mm. An initial NASA disk bolt hole inspection at 665 cycles is suggested with 50 cycle inspection intervals thereafter to monitor fatigue crack growth.

  13. Adsorption of bentazon on CAT and CARBOPAL activated carbon: Experimental and computational study

    NASA Astrophysics Data System (ADS)

    Spaltro, Agustín; Simonetti, Sandra; Torrellas, Silvia Alvarez; Rodriguez, Juan Garcia; Ruiz, Danila; Juan, Alfredo; Allegretti, Patricia

    2018-03-01

    Removal of the bentazon by adsorption on two different types of activated carbon was investigated under various experimental conditions.Kinetics of adsorption is followed and the adsorption isotherms of the pesticide are determined. The effects of the changes in pH, ionic strength and temperature are analyzed. Computational simulation was employed to analyze the geometry and the energy of pesticide absorption on activated carbon. Concentration of bentazon decreases while increase all the variables, from the same initial concentration. Experimental data for equilibrium was analyzed by three models: Langmuir, Freundlich and Guggenheim-Anderson-de Boer isotherms. Pseudo-first and pseudo-second-order kinetics are tested with the experimental data, and pseudo-second-order kinetics was the best for the adsorption of bentazon by CAT and CARBOPAL with coefficients of correlation R2 = 0.9996 and R2 = 0.9993, respectively. The results indicated that both CAT and CARBOPAL are very effective for the adsorption of bentazon from aqueous solutions, but CAT carbon has the greater capacity.

  14. Experimental investigation on the development characteristics of initial electrons in a gas pressurized closing switch under DC voltage

    NASA Astrophysics Data System (ADS)

    Rongxiao, ZHAI; Mengtong, QIU; Weixi, LUO; Peitian, CONG; Tao, HUANG; Jiahui, YIN; Tianyang, ZHANG

    2018-04-01

    As one of the most important elements in linear transformer driver (LTD) based systems, the gas pressurized closing switches are required to operate with a very low prefire probability during the DC-charging process to ensure reliable operation and stable output of the whole pulsed power system. The most direct and effective way to control the prefire probability is to select a suitable working coefficient. The study of the development characteristics of the initially generated electrons is useful for optimizing the working coefficient and improving the prefire characteristic of the switches. In this paper an ultraviolet pulsed laser is used to generate initial electrons inside the gap volume. A current measuring system is used to measure the time-dependent current generated by the growth of the initial electrons so as to study the development characteristics of the electrons under different working coefficients. Experimental results show that the development characteristics of the initial electrons are influenced obviously by the working coefficient. With the increase of the working coefficient, the development degree of the electrons increases consequently. At the same times, there is a threshold of working coefficient which produces the effect of ionization on electrons. The range of the threshold has a slow growth but remains close to 65% with the gas pressure increase. When the working coefficient increases further, γ processes are starting to be generated inside the gap volume. In addition, an optimal working coefficient beneficial for improving the prefire characteristic is indicated and further tested.

  15. Experimental test of an online ion-optics optimizer

    NASA Astrophysics Data System (ADS)

    Amthor, A. M.; Schillaci, Z. M.; Morrissey, D. J.; Portillo, M.; Schwarz, S.; Steiner, M.; Sumithrarachchi, Ch.

    2018-07-01

    A technique has been developed and tested to automatically adjust multiple electrostatic or magnetic multipoles on an ion optical beam line - according to a defined optimization algorithm - until an optimal tune is found. This approach simplifies the process of determining high-performance optical tunes, satisfying a given set of optical properties, for an ion optical system. The optimization approach is based on the particle swarm method and is entirely model independent, thus the success of the optimization does not depend on the accuracy of an extant ion optical model of the system to be optimized. Initial test runs of a first order optimization of a low-energy (<60 keV) all-electrostatic beamline at the NSCL show reliable convergence of nine quadrupole degrees of freedom to well-performing tunes within a reasonable number of trial solutions, roughly 500, with full beam optimization run times of roughly two hours. Improved tunes were found both for quasi-local optimizations and for quasi-global optimizations, indicating a good ability of the optimizer to find a solution with or without a well defined set of initial multipole settings.

  16. A novel approach on accelerated ageing towards reliability optimization of high concentration photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Tsanakas, John A.; Jaffre, Damien; Sicre, Mathieu; Elouamari, Rachid; Vossier, Alexis; de Salins, Jean-Edouard; Bechou, Laurent; Levrier, Bruno; Perona, Arnaud; Dollet, Alain

    2014-09-01

    This paper presents a preliminary study upon a novel approach proposed for highly accelerated ageing and reliability optimization of high concentrating photovoltaic (HCPV) cells and assemblies. The intended approach aims to overcome several limitations of some current accelerated ageing tests (AAT) adopted up today, proposing the use of an alternative experimental set-up for performing faster and more realistic thermal cycles, under real sun, without the involvement of environmental chamber. The study also includes specific characterization techniques, before and after each AAT sequence, which respectively provide the initial and final diagnosis on the condition of the tested sample. The acquired data from these diagnostic/characterization methods are then used as indices to determine both quantitatively and qualitatively the severity of degradation and, thus, the ageing level for each tested HCPV assembly or cell sample. Ultimate goal of such "initial diagnosis - AAT - final diagnosis" sequences is to provide the basis for a future work on the reliability analysis of the main degradation mechanisms and confident prediction of failure propagation in HCPV cells, by means of acceleration factor (AF) and mean-time-to-failure (MTTF) estimations.

  17. Failure analysis of thick composite cylinders under external pressure

    NASA Technical Reports Server (NTRS)

    Caiazzo, A.; Rosen, B. W.

    1992-01-01

    Failure of thick section composites due to local compression strength and overall structural instability is treated. Effects of material nonlinearity, imperfect fiber architecture, and structural imperfections upon anticipated failure stresses are determined. Comparisons with experimental data for a series of test cylinders are described. Predicting the failure strength of composite structures requires consideration of stability and material strength modes of failure using linear and nonlinear analysis techniques. Material strength prediction requires the accurate definition of the local multiaxial stress state in the material. An elasticity solution for the linear static analysis of thick anisotropic cylinders and rings is used herein to predict the axisymmetric stress state in the cylinders. Asymmetric nonlinear behavior due to initial cylinder out of roundness and the effects of end closure structure are treated using finite element methods. It is assumed that local fiber or ply waviness is an important factor in the initiation of material failure. An analytical model for the prediction of compression failure of fiber composites, which includes the effects of fiber misalignments, matrix inelasticity, and multiaxial applied stresses is used for material strength calculations. Analytical results are compared to experimental data for a series of glass and carbon fiber reinforced epoxy cylinders subjected to external pressure. Recommendations for pretest characterization and other experimental issues are presented. Implications for material and structural design are discussed.

  18. Prediction of phycoremediation of As(III) and As(V) from synthetic wastewater by Chlorella pyrenoidosa using artificial neural network

    NASA Astrophysics Data System (ADS)

    Podder, M. S.; Majumder, C. B.

    2017-11-01

    An artificial neural network (ANN) model was developed to predict the phycoremediation efficiency of Chlorella pyrenoidosa for the removal of both As(III) and As(V) from synthetic wastewater based on 49 data-sets obtained from experimental study and increased the data using CSCF technique. The data were divided into training (60%) validation (20%) and testing (20%) sets. The data collected was used for training a three-layer feed-forward back propagation (BP) learning algorithm having 4-5-1 architecture. The model used tangent sigmoid transfer function at input to hidden layer ( tansing) while a linear transfer function ( purelin) was used at output layer. Comparison between experimental results and model results gave a high correlation coefficient (R allANN 2 equal to 0.99987 for both ions and exhibited that the model was able to predict the phycoremediation of As(III) and As(V) from wastewater. Experimental parameters influencing phycoremediation process like pH, inoculum size, contact time and initial arsenic concentration [either As(III) or As(V)] were investigated. A contact time of 168 h was mainly required for achieving equilibrium at pH 9.0 with an inoculum size of 10% (v/v). At optimum conditions, metal ion uptake enhanced with increasing initial metal ion concentration.

  19. Experimental Analysis of the Role of Fluid Transport Properties in Fluid-Induced Fracture Initiation and Propagation

    NASA Astrophysics Data System (ADS)

    Boutt, D.; McPherson, B. J.; Cook, B. K.; Goodwin, L. B.; Williams, J. R.; Lee, M. Y.; Patteson, R.

    2003-12-01

    It is well known that pore fluid pressure fundamentally influences a rock's mechanical response to stress. However, most measures of the mechanical behavior of rock (e.g. shear strength, Young's modulus) do not incorporate, either explicitly or implicitly, pore fluid pressure or transport properties of rock. Current empirical and theoretical criteria that define the amount of stress a given body of rock can support before fracturing also lack a direct connection between fluid transport and mechanical properties. Our research goal is to use laboratory experimental results to elucidate correlations between rock transport properties and fracture behavior under idealized loading conditions. In strongly coupled fluid-solid systems the evolution of the solid framework is influenced by the fluid and vice versa. These couplings often result in changes of the bulk material properties (i.e. permeability and failure strength) with respect to the fluid's ability to move through the solid and the solids ability to transmit momentum. Feedbacks between fluid and solid framework ultimately play key roles in understanding the spatial and temporal evolution of the coupled fluid-solid system. Discretely coupled models of fluid and solid mechanics were developed a priori to design an experimental approach for testing the role of fluid transport parameters in rock fracture. The experimental approach consists of first loading a fluid saturated cylindrical rock specimen under hydrostatic conditions and then applying a differential stress such that the maximum stress is perpendicular to the cylinder long axis. At the beginning of the test the minimum stress and the fluid pressure are dropped at the same time such that the resulting difference in the initial fluid pressure and the final fluid pressure is greater than the final minimum stress. These loading conditions should produce a fluid driven tensile fracture that is perpendicular to the cylinder long axis. Initial analyses using numerical simulations with similar boundary conditions suggest that resulting fracture propagation rates and fracture spacing are controlled by the rocks hydraulic diffusivity. Modeled rocks with higher permeability had fractures with larger apertures, more localized deformation, and greater fracture spacing. Intuitively, these results are consistent with permeability controlling the time required for pressure to come to equilibrium with the new boundary conditions. Finally, more general goals of this research include using these core-scale experimental data and discrete simulation results to calibrate larger-scale, more traditional continuum models of geologic deformation.

  20. An Experimental Test Facility to Support Development of the Fluoride Salt Cooled High Temperature Reactor

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

    Yoder Jr, Graydon L; Aaron, Adam M; Cunningham, Richard Burns

    2014-01-01

    The need for high-temperature (greater than 600 C) energy exchange and delivery systems is significantly increasing as the world strives to improve energy efficiency and develop alternatives to petroleum-based fuels. Liquid fluoride salts are one of the few energy transport fluids that have the capability of operating at high temperatures in combination with low system pressures. The Fluoride Salt-Cooled High-Temperature Reactor design uses fluoride salt to remove core heat and interface with a power conversion system. Although a significant amount of experimentation has been performed with these salts, specific aspects of this reactor concept will require experimental confirmation during themore » development process. The experimental facility described here has been constructed to support the development of the Fluoride Salt Cooled High Temperature Reactor concept. The facility is capable of operating at up to 700 C and incorporates a centrifugal pump to circulate FLiNaK salt through a removable test section. A unique inductive heating technique is used to apply heat to the test section, allowing heat transfer testing to be performed. An air-cooled heat exchanger removes added heat. Supporting loop infrastructure includes a pressure control system; trace heating system; and a complement of instrumentation to measure salt flow, temperatures, and pressures around the loop. The initial experiment is aimed at measuring fluoride salt heat transfer inside a heated pebble bed similar to that used for the core of the pebble bed advanced high-temperature reactor. This document describes the details of the loop design, auxiliary systems used to support the facility, the inductive heating system, and facility capabilities.« less

  1. Optimization of the photoelectrocatalytic oxidation of landfill leachate using copper and nitrate co-doped TiO2 (Ti) by response surface methodology

    PubMed Central

    Zhou, Shaoqi; Feng, Xinbin

    2017-01-01

    In this paper, a statistically-based experimental design with response surface methodology (RSM) was employed to examine the effects of functional conditions on the photoelectrocatalytic oxidation of landfill leachate using a Cu/N co-doped TiO2 (Ti) electrode. The experimental design method was applied to response surface modeling and the optimization of the operational parameters of the photoelectro-catalytic degradation of landfill leachate using TiO2 as a photo-anode. The variables considered were the initial chemical oxygen demand (COD) concentration, pH and the potential bias. Two dependent parameters were either directly measured or calculated as responses: chemical oxygen demand (COD) removal and total organic carbon (TOC) removal. The results of this investigation reveal that the optimum conditions are an initial pH of 10.0, 4377.98mgL-1 initial COD concentration and 25.0 V of potential bias. The model predictions and the test data were in satisfactory agreement. COD and TOC removals of 67% and 82.5%, respectively, were demonstrated. Under the optimal conditions, GC/MS showed 73 organic micro-pollutants in the raw landfill leachate which included hydrocarbons, aromatic compounds and esters. After the landfill leachate treatment processes, 38 organic micro-pollutants disappeared completely in the photoelectrocatalytic process. PMID:28671943

  2. Summary of NASA/DOE Aileron-Control Development Program for Wind Turbines

    NASA Technical Reports Server (NTRS)

    Miller, D. R.

    1986-01-01

    The development of aileron-control for wind turbines is discussed. Selected wind tunnel test results and full-scale rotor test results are presented for various types of ailerons. Finally, the current status of aileron-control development is discussed. Aileron-control was considered as a method of rotor control for use on wind turbines based on its potential to reduce rotor weight and cost. Following an initial feasibility study, a 20 percent chord aileron-control rotor was fabricated and tested on the NASA/DOE Mod-0 experimental wind turbine. Results from these tests indicated that the 20 percent chord ailerons regulated power and provided overspeed protection, but only over a very limited windspeed range. The next aileron-control rotor to be tested on the Mod-0 had 38 percent chord ailerons and test results showed these ailerons provided overspeed protection and power regulation over the Mod-0's entire operational windspeed range.

  3. NASA Lewis Stirling SPRE testing and analysis with reduced number of cooler tubes

    NASA Technical Reports Server (NTRS)

    Wong, Wayne A.; Cairelli, James E.; Swec, Diane M.; Doeberling, Thomas J.; Lakatos, Thomas F.; Madi, Frank J.

    1992-01-01

    Free-piston Stirling power converters are candidates for high capacity space power applications. The Space Power Research Engine (SPRE), a free-piston Stirling engine coupled with a linear alternator, is being tested at the NASA Lewis Research Center in support of the Civil Space Technology Initiative. The SPRE is used as a test bed for evaluating converter modifications which have the potential to improve the converter performance and for validating computer code predictions. Reducing the number of cooler tubes on the SPRE has been identified as a modification with the potential to significantly improve power and efficiency. Experimental tests designed to investigate the effects of reducing the number of cooler tubes on converter power, efficiency and dynamics are described. Presented are test results from the converter operating with a reduced number of cooler tubes and comparisons between this data and both baseline test data and computer code predictions.

  4. COMBREX-DB: an experiment centered database of protein function: knowledge, predictions and knowledge gaps.

    PubMed

    Chang, Yi-Chien; Hu, Zhenjun; Rachlin, John; Anton, Brian P; Kasif, Simon; Roberts, Richard J; Steffen, Martin

    2016-01-04

    The COMBREX database (COMBREX-DB; combrex.bu.edu) is an online repository of information related to (i) experimentally determined protein function, (ii) predicted protein function, (iii) relationships among proteins of unknown function and various types of experimental data, including molecular function, protein structure, and associated phenotypes. The database was created as part of the novel COMBREX (COMputational BRidges to EXperiments) effort aimed at accelerating the rate of gene function validation. It currently holds information on ∼ 3.3 million known and predicted proteins from over 1000 completely sequenced bacterial and archaeal genomes. The database also contains a prototype recommendation system for helping users identify those proteins whose experimental determination of function would be most informative for predicting function for other proteins within protein families. The emphasis on documenting experimental evidence for function predictions, and the prioritization of uncharacterized proteins for experimental testing distinguish COMBREX from other publicly available microbial genomics resources. This article describes updates to COMBREX-DB since an initial description in the 2011 NAR Database Issue. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  5. Application of Self Nulling Eddy Current Probe Technique to the Detection of Fatigue Crack Initiation and Control of Test Procedures

    NASA Technical Reports Server (NTRS)

    Namkung, M.; Nath, S.; Wincheski, B.; Fulton, J. P.

    1994-01-01

    A major part of fracture mechanics is concerned with studying the initiation and propagation of fatigue cracks. This typically requires constant monitoring of crack growth during fatigue cycles and the knowledge of the precise location of the crack tip at any given time. One technique currently available for measuring fatigue crack length is the Potential Drop method. The method, however, may be inaccurate if the direction of crack growth deviates considerably from what was assumed initially or the curvature of the crack becomes significant. Another popular approach is to optically view the crack using a high magnification microscope, but this entails a person constantly monitoring it. The present proposed technique uses an automated scheme, in order to eliminate the need for a person to constantly monitor the experiment. Another technique under development elsewhere is to digitize an optical image of the test specimen surface and then apply a pattern recognition algorithm to locate the crack tip. A previous publication showed that the self nulling eddy current probe successfully tracked a simulated crack in an aluminum sample. This was the impetus to develop an online real time crack monitoring system. An automated system has been developed which includes a two axis scanner mounted on the tensile testing machine, the probe and its instrumentation and a personal computer (PC) to communicate and control all the parameters. The system software controls the testing parameters as well as monitoring the fatigue crack as it propagates. This paper will discuss the experimental setup in detail and demonstrate its capabilities. A three dimensional finite element model is utilized to model the magnetic field distribution due to the probe and how the probe voltage changes as it scans the crack. Experimental data of the probe for different samples under zero load, static load and high cycle fatigue load will be discussed. The final section summarizes the major accomplishments of the present work, the elements of the future R&D needs and the advantages and disadvantages of using this system in the laboratory and field.

  6. Reactivity Initiated Accident Simulation to Inform Transient Testing of Candidate Advanced Cladding

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

    Brown, Nicholas R; Wysocki, Aaron J; Terrani, Kurt A

    2016-01-01

    Abstract. Advanced cladding materials with potentially enhanced accident tolerance will yield different light water reactor performance and safety characteristics than the present zirconium-based cladding alloys. These differences are due to different cladding material properties and responses to the transient, and to some extent, reactor physics, thermal, and hydraulic characteristics. Some of the differences in reactors physics characteristics will be driven by the fundamental properties (e.g., absorption in iron for an iron-based cladding) and others will be driven by design modifications necessitated by the candidate cladding materials (e.g., a larger fuel pellet to compensate for parasitic absorption). Potential changes in thermalmore » hydraulic limits after transition from the current zirconium-based cladding to the advanced materials will also affect the transient response of the integral fuel. This paper leverages three-dimensional reactor core simulation capabilities to inform on appropriate experimental test conditions for candidate advanced cladding materials in a control rod ejection event. These test conditions are using three-dimensional nodal kinetics simulations of a reactivity initiated accident (RIA) in a representative state-of-the-art pressurized water reactor with both nuclear-grade iron-chromium-aluminum (FeCrAl) and silicon carbide based (SiC-SiC) cladding materials. The effort yields boundary conditions for experimental mechanical tests, specifically peak cladding strain during the power pulse following the rod ejection. The impact of candidate cladding materials on the reactor kinetics behavior of RIA progression versus reference zirconium cladding is predominantly due to differences in: (1) fuel mass/volume/specific power density, (2) spectral effects due to parasitic neutron absorption, (3) control rod worth due to hardened (or softened) spectrum, and (4) initial conditions due to power peaking and neutron transport cross sections in the equilibrium cycle cores due to hardened (or softened) spectrum. This study shows minimal impact of SiC-based cladding configurations on the transient response versus reference zirconium-based cladding. However, the FeCrAl cladding response indicates similar energy deposition, but with significantly shorter pulses of higher magnitude. Therefore the FeCrAl-based cases have a more rapid fuel thermal expansion rate and the resultant pellet-cladding interaction occurs more rapidly.« less

  7. Self-pressurization of a flightweight liquid hydrogen storage tank subjected to low heat flux

    NASA Technical Reports Server (NTRS)

    Hasan, M. M.; Lin, C. S.; Vandresar, N. T.

    1991-01-01

    Results are presented for an experimental investigation of self-pressurization and thermal stratification of a 4.89 cu m liquid hydrogen (LH2) storage tank subjected to low heat flux (0.35, 2.0, and 3.5 W/sq m) under normal gravity conditions. Tests were performed at fill levels of 83 to 84 percent (by volume). The LH2 tank was representative of future spacecraft tankage, having a low mass-to-volume ratio and high performance multilayer thermal insulation. Results show that the pressure rise rate and thermal stratification increase with increasing heat flux. At the lowest heat flux, the pressure rise rate is comparable to the homogenous rate, while at the highest heat flux, the rate is more than three times the homogeneous rate. It was found that initial conditions have a significant impact on the initial pressure rise rate. The quasi-steady pressure rise rates are nearly independent of the initial condition after an initial transient period has passed.

  8. Insight and search in Katona's five-square problem.

    PubMed

    Ollinger, Michael; Jones, Gary; Knoblich, Günther

    2014-01-01

    Insights are often productive outcomes of human thinking. We provide a cognitive model that explains insight problem solving by the interplay of problem space search and representational change, whereby the problem space is constrained or relaxed based on the problem representation. By introducing different experimental conditions that either constrained the initial search space or helped solvers to initiate a representational change, we investigated the interplay of problem space search and representational change in Katona's five-square problem. Testing 168 participants, we demonstrated that independent hints relating to the initial search space and to representational change had little effect on solution rates. However, providing both hints caused a significant increase in solution rates. Our results show the interplay between problem space search and representational change in insight problem solving: The initial problem space can be so large that people fail to encounter impasse, but even when representational change is achieved the resulting problem space can still provide a major obstacle to finding the solution.

  9. Impact initiation of reactive aluminized fluorinated acrylic nanocomposites

    DOE PAGES

    White, Bradley W.; Crouse, Christopher A.; Spowart, Jonathan E.; ...

    2016-04-18

    The initiation of aluminized fluorinated acrylic (AlFA) nanocomposites during modified Taylor impact tests was investigated. Samples were impacted against a steel or sapphire anvil at a nominal velocity of 150 m/s. A framing camera was used to capture head-on and side-profile impact images for the sapphire window and steel plate rigid anvils, respectively. Correlations were drawn between both experimental setups to determine the initiation locations and reaction times. Reactions were found to initiate at an intermediate radius on the impact face of the pellet at a time near full compaction. From simulations, the highest strains and temperatures were found atmore » radii similar to those observed in experiments at the time of ignition. Off-normal impacts produced higher localized straining and temperatures on one-half of the pellet. As a result, the copper projectile, used for delivery, was revealed to aid in a shear assisted reaction by helping to drive the pellet material outward as the projectile deformed radially.« less

  10. Investigation on temporal evolution of the grain refinement in copper under high strain rate loading via in-situ synchrotron measurement and predictive modeling

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

    Shah, Pooja Nitin; Shin, Yung C.; Sun, Tao

    Synchrotron X-rays are integrated with a modified Kolsky tension bar to conduct in situ tracking of the grain refinement mechanism operating during the dynamic deformation of metals. Copper with an initial average grain size of 36 μm is refined to 6.3 μm when loaded at a constant high strain rate of 1200 s -1. The synchrotron measurements revealed the temporal evolution of the grain refinement mechanism in terms of the initiation and rate of refinement throughout the loading test. A multiscale coupled probabilistic cellular automata based recrystallization model has been developed to predict the microstructural evolution occurring during dynamic deformationmore » processes. The model accurately predicts the initiation of the grain refinement mechanism with a predicted final average grain size of 2.4 μm. As a result, the model also accurately predicts the temporal evolution in terms of the initiation and extent of refinement when compared with the experimental results.« less

  11. Decomposing mechanisms of abnormal saccade generation in schizophrenia patients: Contributions of volitional initiation, motor preparation, and fixation release.

    PubMed

    Reuter, Benedikt; Elsner, Björn; Möllers, David; Kathmann, Norbert

    2016-11-01

    Clinical and theoretical models suggest deficient volitional initiation of action in schizophrenia patients. Recent research provided an experimental model of testing this assumption using saccade tasks. However, inconsistent findings necessitate a specification of conditions on which the deficit may occur. The present study sought to detect mechanisms that may contribute to poor performance. Sixteen schizophrenia patients and 16 healthy control participants performed visually guided and two types of volitional saccade tasks. All tasks varied as to whether the initial fixation stimulus disappeared (fixation stimulus offset) or continued during saccade initiation, and whether a direction cue allowed motor preparation of the specific saccade. Saccade latencies of the two groups were differentially affected by task type, fixation stimulus offset, and cueing, suggesting abnormal volitional saccade generation, fixation release, and motor preparation in schizophrenia. However, substantial performance deficits may only occur if all affected processes are required in a task. © 2016 Society for Psychophysiological Research.

  12. Investigation on temporal evolution of the grain refinement in copper under high strain rate loading via in-situ synchrotron measurement and predictive modeling

    DOE PAGES

    Shah, Pooja Nitin; Shin, Yung C.; Sun, Tao

    2017-10-03

    Synchrotron X-rays are integrated with a modified Kolsky tension bar to conduct in situ tracking of the grain refinement mechanism operating during the dynamic deformation of metals. Copper with an initial average grain size of 36 μm is refined to 6.3 μm when loaded at a constant high strain rate of 1200 s -1. The synchrotron measurements revealed the temporal evolution of the grain refinement mechanism in terms of the initiation and rate of refinement throughout the loading test. A multiscale coupled probabilistic cellular automata based recrystallization model has been developed to predict the microstructural evolution occurring during dynamic deformationmore » processes. The model accurately predicts the initiation of the grain refinement mechanism with a predicted final average grain size of 2.4 μm. As a result, the model also accurately predicts the temporal evolution in terms of the initiation and extent of refinement when compared with the experimental results.« less

  13. Impact initiation of reactive aluminized fluorinated acrylic nanocomposites

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

    White, Bradley W.; Crouse, Christopher A.; Spowart, Jonathan E.

    The initiation of aluminized fluorinated acrylic (AlFA) nanocomposites during modified Taylor impact tests was investigated. Samples were impacted against a steel or sapphire anvil at a nominal velocity of 150 m/s. A framing camera was used to capture head-on and side-profile impact images for the sapphire window and steel plate rigid anvils, respectively. Correlations were drawn between both experimental setups to determine the initiation locations and reaction times. Reactions were found to initiate at an intermediate radius on the impact face of the pellet at a time near full compaction. From simulations, the highest strains and temperatures were found atmore » radii similar to those observed in experiments at the time of ignition. Off-normal impacts produced higher localized straining and temperatures on one-half of the pellet. As a result, the copper projectile, used for delivery, was revealed to aid in a shear assisted reaction by helping to drive the pellet material outward as the projectile deformed radially.« less

  14. Experimental Evaluation of Fatigue Damage Progression in Postbuckled Single Stringer Composite Specimens

    NASA Technical Reports Server (NTRS)

    Bisagni, Chiara; Davila, Carlos G.; Rose, Cheryl A.; Zalameda, Joseph N.

    2014-01-01

    The durability and damage tolerance of postbuckled composite structures are not yet completely understood, and remain difficult to predict due to the nonlinearity of the geometric response and its interaction with local damage modes. A research effort was conducted to investigate experimentally the quasi-static and fatigue damage progression in a single-stringer compression (SSC) specimen. Three specimens were manufactured with a hat-stiffener, and an initial defect was introduced with a Teflon film embedded between one flange of the stringer and the skin. One of the specimens was tested under quasi-static compressive loading, while the remaining two specimens were tested by cycling in postbuckling. The tests were performed at the NASA Langley Research Center under controlled conditions and with instrumentation that allows a precise evaluation of the postbuckling response and of the damage modes. Three-dimensional digital image correlation VIC-3D systems were used to provide full field displacements and strains on the skin and the stringer. Passive thermal monitoring was conducted during the fatigue tests using an infrared camera that showed the location of the delamination front while the specimen was being cycled. The live information from the thermography was used to stop the fatigue tests at critical stages of the damage evolution to allow detailed ultrasonic scans.

  15. Experimental Determination of Frost Resistance of Autoclaved Aerated Concrete at Different Levels of Moisture Saturation

    NASA Astrophysics Data System (ADS)

    Kočí, Václav; Maděra, Jiří; Jerman, Miloš; Černý, Robert

    2018-06-01

    The ability of porous building materials to stand up to moisture phase changes induced by alternating environment is described mostly by means of their frost resistance. However, the test conditions defined by relevant standards might not capture the real situation on building site in various locations. In particular, the prescribed full water saturation of analyzed specimens during the whole time of a freeze/thaw experiment presents an ultimate case only but certainly not an everyday reality. Even the materials of surface layers are mostly exposed to such severe conditions just for a limited period of time. In this paper, the experimental analysis of frost resistance of three different types of autoclaved aerated concrete (AAC) is performed in an extended way, including not only the standard testing but also the investigation of dry- and partially saturated samples. A complementary computational analysis of an AAC building envelope in Central European climate is presented as well, in order to illustrate the likely hygric conditions in the wall. Experimental results show that according to the standard test the loss of compressive strength, as well as the loss of mass after 25 cycles, is acceptable for all studied samples but after 50 cycles only the material with the compressive strength of 4 MPa performs satisfactorily. On the other hand, the tests with initially dried or partially saturated samples indicate a good frost resistance of all studied materials for both 25 and 50 cycles.

  16. Experimental Verification of the Structural Glass Beam-Columns Strength

    NASA Astrophysics Data System (ADS)

    Pešek, Ondřej; Melcher, Jindřich; Balázs, Ivan

    2017-10-01

    This paper deals with experimental research of axially and laterally loaded members made of structural (laminated) glass. The purpose of the research is the evaluation of buckling strength and actual behaviour of the beam-columns due to absence of standards for design of glass load-bearing structures. The experimental research follows the previous one focusing on measuring of initial geometrical imperfections of glass members, testing of glass beams and columns. Within the frame of the research 9 specimens were tested. All of them were of the same geometry (length 2000 mm, width 200 mm and thickness 16 mm) but different composition - laminated double glass made of annealed glass or fully tempered glass panes bonded together by PVB or EVASAFE foil. Specimens were at first loaded by axial force and then by constantly increasing bending moment up to failure. During testing lateral deflections, vertical deflection and normal stresses at mid-span were measured. A maximum load achieved during testing has been adopted as flexural-lateral-torsional buckling strength. The results of experiments were statistically evaluated according to the European standard for design of structures EN 1990, appendix D. There are significant differences between specimens made of annealed glass or fully tempered glass. Differences between specimens loaded by axial forces 1 kN and 2 kN are negligible. The next step was to determine the design strength by calculation procedure based on buckling curves approach intended for design of steel columns and develop interaction criterion for glass beams-columns.

  17. Integrating Multiple On-line Knowledge Bases for Disease-Lab Test Relation Extraction.

    PubMed

    Zhang, Yaoyun; Soysal, Ergin; Moon, Sungrim; Wang, Jingqi; Tao, Cui; Xu, Hua

    2015-01-01

    A computable knowledge base containing relations between diseases and lab tests would be a great resource for many biomedical informatics applications. This paper describes our initial step towards establishing a comprehensive knowledge base of disease and lab tests relations utilizing three public on-line resources. LabTestsOnline, MedlinePlus and Wikipedia are integrated to create a freely available, computable disease-lab test knowledgebase. Disease and lab test concepts are identified using MetaMap and relations between diseases and lab tests are determined based on source-specific rules. Experimental results demonstrate a high precision for relation extraction, with Wikipedia achieving the highest precision of 87%. Combining the three sources reached a recall of 51.40%, when compared with a subset of disease-lab test relations extracted from a reference book. Moreover, we found additional disease-lab test relations from on-line resources, indicating they are complementary to existing reference books for building a comprehensive disease and lab test relation knowledge base.

  18. Design and Testing for a New Thermosyphon Irradiation Vehicle

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

    Felde, David K.; Carbajo, Juan J.; McDuffee, Joel Lee

    The High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory (ORNL) requires most materials and all fuel experiments to be placed in a pressure containment vessel to ensure that internal contaminants such as fission products cannot be released into the primary coolant. It also requires that all experiments be capable of withstanding various accident conditions (e.g., loss of coolant) without generating vapor bubbles on the surface of the experiment in the primary coolant. These requirements are intended to artificially increase experiment temperatures by introducing a barrier between the experimental materials and the HFIR coolant, and by reducing heatmore » loads to the HFIR primary coolant, thus ensuring that no boiling can occur. A proposed design for materials irradiation would remove these limitations by providing the required primary containment with an internal cooling flow. This would allow for experiments to be irradiated without concern for coolant contamination (e.g., from cladding failure of advanced fuel pins) or for specimen heat load. This report describes a new materials irradiation experiment design that uses a thermosyphon cooling system to allow experimental materials direct access to a liquid coolant. The new design also increases the range of conditions that can be tested in HFIR. This design will provide a unique capability to validate the performance of current and advanced fuels and materials. Because of limited supporting data for this kind of irradiation vehicle, a test program was initiated to obtain operating data that can be used to (1) qualify the vehicle for operation in HFIR and (2) validate computer models used to perform design- and safety-basis calculations. This report also describes the test facility and experimental data, and it provides a comparison of the experimental data to computer simulations. A total of 51 tests have been completed: four tests with pure steam, 12 tests with argon, and 35 tests with helium. A total of 10 tests were performed at subatmospheric pressure, and four of these were performed with pure steam. One test was conducted at a high power of 92.7 kW, six tests were HFIR startups, and two tests were HFIR loss of offsite power (LOOP). Pressures up to 10 MPa, vapor temperatures up to 583 K (310°C), and heater temperatures above 600 K (327°C) have been reached in these tests. Two computer programs, RELAP5-3D and TRACE, have been used to simulate the tests. The TRACE code has shown good agreement with the test data and has been used to model a variety of tests. This experimental facility has been very useful in demonstrating the viability of this new type of irradiation facility.« less

  19. Flow and fracture behavior of aluminum alloy 6082-T6 at different tensile strain rates and triaxialities

    PubMed Central

    Chen, Xuanzhen; Peng, Shan; Yao, Song; Chen, Chao; Xu, Ping

    2017-01-01

    This study aims to investigate the flow and fracture behavior of aluminum alloy 6082-T6 (AA6082-T6) at different strain rates and triaxialities. Two groups of Charpy impact tests were carried out to further investigate its dynamic impact fracture property. A series of tensile tests and numerical simulations based on finite element analysis (FEA) were performed. Experimental data on smooth specimens under various strain rates ranging from 0.0001~3400 s-1 shows that AA6082-T6 is rather insensitive to strain rates in general. However, clear rate sensitivity was observed in the range of 0.001~1 s-1 while such a characteristic is counteracted by the adiabatic heating of specimens under high strain rates. A Johnson-Cook constitutive model was proposed based on tensile tests at different strain rates. In this study, the average stress triaxiality and equivalent plastic strain at facture obtained from numerical simulations were used for the calibration of J-C fracture model. Both of the J-C constitutive model and fracture model were employed in numerical simulations and the results was compared with experimental results. The calibrated J-C fracture model exhibits higher accuracy than the J-C fracture model obtained by the common method in predicting the fracture behavior of AA6082-T6. Finally, the Scanning Electron Microscope (SEM) of fractured specimens with different initial stress triaxialities were analyzed. The magnified fractographs indicate that high initial stress triaxiality likely results in dimple fracture. PMID:28759617

  20. Approach and Instrument Placement Validation

    NASA Technical Reports Server (NTRS)

    Ator, Danielle

    2005-01-01

    The Mars Exploration Rovers (MER) from the 2003 flight mission represents the state of the art technology for target approach and instrument placement on Mars. It currently takes 3 sols (Martian days) for the rover to place an instrument on a designated rock target that is about 10 to 20 m away. The objective of this project is to provide an experimentally validated single-sol instrument placement capability to future Mars missions. After completing numerous test runs on the Rocky8 rover under various test conditions, it has been observed that lighting conditions, shadow effects, target features and the initial target distance have an effect on the performance and reliability of the tracking software. Additional software validation testing will be conducted in the months to come.

  1. Damage Characteristics and Residual Strength of Composite Sandwich Panels Impacted with and Without Compression Loading

    NASA Technical Reports Server (NTRS)

    McGowan, David M.; Ambur, Damodar R.

    1998-01-01

    The results of an experimental study of the impact damage characteristics and residual strength of composite sandwich panels impacted with and without a compression loading are presented. Results of impact damage screening tests conducted to identify the impact-energy levels at which damage initiates and at which barely visible impact damage occurs in the impacted facesheet are discussed. Parametric effects studied in these tests include the impactor diameter, dropped-weight versus airgun-launched impactors, and the effect of the location of the impact site with respect to the panel boundaries. Residual strength results of panels tested in compression after impact are presented and compared with results of panels that are subjected to a compressive preload prior to being impacted.

  2. The Enzyme Function Initiative.

    PubMed

    Gerlt, John A; Allen, Karen N; Almo, Steven C; Armstrong, Richard N; Babbitt, Patricia C; Cronan, John E; Dunaway-Mariano, Debra; Imker, Heidi J; Jacobson, Matthew P; Minor, Wladek; Poulter, C Dale; Raushel, Frank M; Sali, Andrej; Shoichet, Brian K; Sweedler, Jonathan V

    2011-11-22

    The Enzyme Function Initiative (EFI) was recently established to address the challenge of assigning reliable functions to enzymes discovered in bacterial genome projects; in this Current Topic, we review the structure and operations of the EFI. The EFI includes the Superfamily/Genome, Protein, Structure, Computation, and Data/Dissemination Cores that provide the infrastructure for reliably predicting the in vitro functions of unknown enzymes. The initial targets for functional assignment are selected from five functionally diverse superfamilies (amidohydrolase, enolase, glutathione transferase, haloalkanoic acid dehalogenase, and isoprenoid synthase), with five superfamily specific Bridging Projects experimentally testing the predicted in vitro enzymatic activities. The EFI also includes the Microbiology Core that evaluates the in vivo context of in vitro enzymatic functions and confirms the functional predictions of the EFI. The deliverables of the EFI to the scientific community include (1) development of a large-scale, multidisciplinary sequence/structure-based strategy for functional assignment of unknown enzymes discovered in genome projects (target selection, protein production, structure determination, computation, experimental enzymology, microbiology, and structure-based annotation), (2) dissemination of the strategy to the community via publications, collaborations, workshops, and symposia, (3) computational and bioinformatic tools for using the strategy, (4) provision of experimental protocols and/or reagents for enzyme production and characterization, and (5) dissemination of data via the EFI's Website, http://enzymefunction.org. The realization of multidisciplinary strategies for functional assignment will begin to define the full metabolic diversity that exists in nature and will impact basic biochemical and evolutionary understanding, as well as a wide range of applications of central importance to industrial, medicinal, and pharmaceutical efforts. © 2011 American Chemical Society

  3. Direction of illumination controls gametophyte orientation in seedless plants and related algae

    PubMed Central

    Cardona-Correa, Christopher; Ecker, Alice; Graham, Linda E

    2015-01-01

    The environmental influences that determine dorsiventral or axial gametophyte orientation are unknown for most modern seedless plants. To fill this gap, an experimental laboratory system was employed to evaluate the relative effects of light direction and gravity on body orientation of the dorsiventral green alga Coleochaete orbicularis, and gametophytes of liverworts Blasia pusilla and Marchantia polymorpha, early-diverging moss Sphagnum compactum, and fern Ceratopteris richardii, the latter functioning as experimental control. Replicate clonal cultures were experimentally illuminated only from above, only from below, or from multiple directions, with the same near-saturation PAR level for periods brief enough to minimize nutrient limitation effects, and orientation of new growth was evaluated. For all species tested, direction of illumination exerted stronger control over gametophyte body orientation than gravity. When illuminated only from below: 1) axial Sphagnum gametophores that had initially grown into an overlying air space inverted growth by 180°, burrowing into the substrate; 2) new growth of dorsiventral Blasia, Marchantia, and Ceratopteris gametophytes–whose ventral rhizoids initially penetrated agar substrate and dorsal surfaces initially faced overlying airspace–twisted 180° so that ventral surfaces bearing rhizoids faced overlying air space and rhizoids extended into the air; and 3) Coleochaete lost typical dorsiventral organization and diagnostic dorsal hairs. Direction of illumination also exerted stronger control over orientation of liverwort new growth than surface contact did. These results indicate that early land plants likely inherited light-directed gametophyte body orientation from ancestral streptophyte algae and suggest a mechanism for reorientation of gametophyte-dominant land plants after spatial disturbance. PMID:26237278

  4. Direction of illumination controls gametophyte orientation in seedless plants and related algae.

    PubMed

    Cardona-Correa, Christopher; Ecker, Alice; Graham, Linda E

    2015-01-01

    The environmental influences that determine dorsiventral or axial gametophyte orientation are unknown for most modern seedless plants. To fill this gap, an experimental laboratory system was employed to evaluate the relative effects of light direction and gravity on body orientation of the dorsiventral green alga Coleochaete orbicularis, and gametophytes of liverworts Blasia pusilla and Marchantia polymorpha, early-diverging moss Sphagnum compactum, and fern Ceratopteris richardii, the latter functioning as experimental control. Replicate clonal cultures were experimentally illuminated only from above, only from below, or from multiple directions, with the same near-saturation PAR level for periods brief enough to minimize nutrient limitation effects, and orientation of new growth was evaluated. For all species tested, direction of illumination exerted stronger control over gametophyte body orientation than gravity. When illuminated only from below: 1) axial Sphagnum gametophores that had initially grown into an overlying air space inverted growth by 180°, burrowing into the substrate; 2) new growth of dorsiventral Blasia, Marchantia, and Ceratopteris gametophytes-whose ventral rhizoids initially penetrated agar substrate and dorsal surfaces initially faced overlying airspace-twisted 180° so that ventral surfaces bearing rhizoids faced overlying air space and rhizoids extended into the air; and 3) Coleochaete lost typical dorsiventral organization and diagnostic dorsal hairs. Direction of illumination also exerted stronger control over orientation of liverwort new growth than surface contact did. These results indicate that early land plants likely inherited light-directed gametophyte body orientation from ancestral streptophyte algae and suggest a mechanism for reorientation of gametophyte-dominant land plants after spatial disturbance.

  5. TR-IA payload recovery system

    NASA Astrophysics Data System (ADS)

    Kochiyama, Jiro; Kinai, Shigeki; Morita, Shinya

    The TR-IA microgravity-experimentation sounding rocket baseline configuration and recovery system are presented. Aerodynamic braking is incorporated through the requisite positioning of the reentry-body center of gravity. The recovery sequence is initiated by baroswitches, which eject the pilot chute. Even in the event of flotation bag malfunction, the structure containing the experiment is watertight. An account is given of the nature and the results of the performance tests conducted to establish the soundness of various materials and components.

  6. Active and passive multispectral scanner for earth resources applications: An advanced applications flight experiment

    NASA Technical Reports Server (NTRS)

    Hasell, P. G., Jr.; Peterson, L. M.; Thomson, F. J.; Work, E. A.; Kriegler, F. J.

    1977-01-01

    The development of an experimental airborne multispectral scanner to provide both active (laser illuminated) and passive (solar illuminated) data from a commonly registered surface scene is discussed. The system was constructed according to specifications derived in an initial programs design study. The system was installed in an aircraft and test flown to produce illustrative active and passive multi-spectral imagery. However, data was not collected nor analyzed for any specific application.

  7. Two-phase working fluids for the temperature range 100-350 C. [in heat pipes for solar applications

    NASA Technical Reports Server (NTRS)

    Saaski, E. W.; Tower, L.

    1977-01-01

    The decomposition and corrosion of two-phase heat transfer liquids and metal envelopes have been investigated on the basis of molecular, bond strengths and chemical thermodynamics. Potentially stable heat transfer fluids for the temperature range 100 to 350 C have been identified, and reflux heat pipe tests initiated with 10 fluids and carbon steel and aluminum envelopes to experimentally establish corrosion behavior and noncondensable gas generation rates.

  8. On the tensile strength of soil grains in Hertzian response

    NASA Astrophysics Data System (ADS)

    Nadimi, Sadegh; Fonseca, Joana

    2017-06-01

    The breakage initiation of soil grains is controlled by its tensile capacity. Despite the importance of tensile strength, it is often disregarded due to difficulties in measurement. This paper presents an experimental and numerical investigation on the effect of tensile strength on Hertzian response of a single soil grain. Hertz theory is commonly used in numerical simulation to present the contact constitutive behaviour of a purely elastic grain under normal loading. This normal force:displacement comes from stress distribution and concentration inside the grain. When the stress reaches the tensile capacity, a crack initiates. A series of numerical tests have been conducted to determine the sensitivity of Hertzian response to the selected tensile strength used as an input data. An elastic-damage constitutive model has been employed for spherical grains in a combined finite-discrete element framework. The interpretation of results was enriched by considering previous theoretical work. In addition, systematic experimental tests have been carried out on both spherical glass beads and grains of two different sands, i.e. Leighton Buzzard silica sand and coarse carbonate sand from Persian Gulf. The preliminary results suggest that lower tensile strength leads to a softer response under normal loading. The wider range of responses obtained for the carbonate sand, are believed to be related to the large variety of grain shape associated with bioclastic origin of the constituent grains.

  9. A Novel Method to Simulate the Progression of Collagen Degeneration of Cartilage in the Knee: Data from the Osteoarthritis Initiative

    PubMed Central

    Mononen, Mika E.; Tanska, Petri; Isaksson, Hanna; Korhonen, Rami K.

    2016-01-01

    We present a novel algorithm combined with computational modeling to simulate the development of knee osteoarthritis. The degeneration algorithm was based on excessive and cumulatively accumulated stresses within knee joint cartilage during physiological gait loading. In the algorithm, the collagen network stiffness of cartilage was reduced iteratively if excessive maximum principal stresses were observed. The developed algorithm was tested and validated against experimental baseline and 4-year follow-up Kellgren-Lawrence grades, indicating different levels of cartilage degeneration at the tibiofemoral contact region. Test groups consisted of normal weight and obese subjects with the same gender and similar age and height without osteoarthritic changes. The algorithm accurately simulated cartilage degeneration as compared to the Kellgren-Lawrence findings in the subject group with excess weight, while the healthy subject group’s joint remained intact. Furthermore, the developed algorithm followed the experimentally found trend of cartilage degeneration in the obese group (R2 = 0.95, p < 0.05; experiments vs. model), in which the rapid degeneration immediately after initiation of osteoarthritis (0–2 years, p < 0.001) was followed by a slow or negligible degeneration (2–4 years, p > 0.05). The proposed algorithm revealed a great potential to objectively simulate the progression of knee osteoarthritis. PMID:26906749

  10. Experimental Infection of Plants with an Herbivore-Associated Bacterial Endosymbiont Influences Herbivore Host Selection Behavior

    PubMed Central

    Davis, Thomas Seth; Horton, David R.; Munyaneza, Joseph E.; Landolt, Peter J.

    2012-01-01

    Although bacterial endosymbioses are common among phloeophagous herbivores, little is known regarding the effects of symbionts on herbivore host selection and population dynamics. We tested the hypothesis that plant selection and reproductive performance by a phloem-feeding herbivore (potato psyllid, Bactericera cockerelli) is mediated by infection of plants with a bacterial endosymbiont. We controlled for the effects of herbivory and endosymbiont infection by exposing potato plants (Solanum tuberosum) to psyllids infected with “Candidatus Liberibacter solanacearum” or to uninfected psyllids. We used these treatments as a basis to experimentally test plant volatile emissions, herbivore settling and oviposition preferences, and herbivore population growth. Three important findings emerged: (1) plant volatile profiles differed with respect to both herbivory and herbivory plus endosymbiont infection when compared to undamaged control plants; (2) herbivores initially settled on plants exposed to endosymbiont-infected psyllids but later defected and oviposited primarily on plants exposed only to uninfected psyllids; and (3) plant infection status had little effect on herbivore reproduction, though plant flowering was associated with a 39% reduction in herbivore density on average. Our experiments support the hypothesis that plant infection with endosymbionts alters plant volatile profiles, and infected plants initially recruited herbivores but later repelled them. Also, our findings suggest that the endosymbiont may not place negative selection pressure on its host herbivore in this system, but plant flowering phenology appears correlated with psyllid population performance. PMID:23166641

  11. Unusual plastic deformation and damage features in titanium: Experimental tests and constitutive modeling

    NASA Astrophysics Data System (ADS)

    Revil-Baudard, Benoit; Cazacu, Oana; Flater, Philip; Chandola, Nitin; Alves, J. L.

    2016-03-01

    In this paper, we present an experimental study on plastic deformation and damage of polycrystalline pure HCP Ti, as well as modeling of the observed behavior. Mechanical characterization data were conducted, which indicate that the material is orthotropic and displays tension-compression asymmetry. The ex-situ and in-situ X-ray tomography measurements conducted reveal that damage distribution and evolution in this HCP Ti material is markedly different than in a typical FCC material such as copper. Stewart and Cazacu (2011) anisotropic elastic/plastic damage model is used to describe the behavior. All the parameters involved in this model have a clear physical significance, being related to plastic properties, and are determined from very few simple mechanical tests. It is shown that this model predicts correctly the anisotropy in plastic deformation, and its strong influence on damage distribution and damage accumulation. Specifically, for a smooth axisymmetric specimen subject to uniaxial tension, damage initiates at the center of the specimen, and is diffuse; the level of damage close to failure being very low. On the other hand, for a notched specimen subject to the same loading the model predicts that damage initiates at the outer surface of the specimen, and further grows from the outer surface to the center of the specimen, which corroborates with the in-situ tomography data.

  12. Experimental investigation on mass flow rate measurements using fibre Bragg grating sensors

    NASA Astrophysics Data System (ADS)

    Thekkethil, S. R.; Thomas, R. J.; Neumann, H.; Ramalingam, R.

    2017-02-01

    Flow measurement and control of cryogens is one of the major requirements of systems such as superconductor magnets for fusion reactors, MRI magnets etc. They can act as an early diagnostic tool for detection of any faults and ensure correct distribution of cooling load while also accessing thermal performance of the devices. Fibre Bragg Grating (FBG) sensors provide compact and accurate measurement systems which have added advantages such as immunity towards electrical and magnetic interference, low attenuation losses and remote sensing. This paper summarizes the initial experimental investigations and calibration of a novel FBG based mass flow meter. This design utilizes the viscous drag due to the flow to induce a bending strain on the fibre. The strain experienced by the fibre will be proportional to the flowrate and can be measured in terms of Bragg wavelength shift. The flowmeter is initially tested at atmospheric conditions using helium. The results are summarized and the performance parameters of the sensor are estimated. The results were also compared to a numerical model and further results for liquid helium is also reported. An overall sensitivity of 29 pm.(g.s-1)-1 was obtained for a helium flow, with a resolution of 0.2 g.s-1. A hysteresis error of 8 pm was also observed during load-unload cycles. The sensor is suitable for further tests using cryogens.

  13. Advanced Motor Control Test Facility for NASA GRC Flywheel Energy Storage System Technology Development Unit

    NASA Technical Reports Server (NTRS)

    Kenny, Barbara H.; Kascak, Peter E.; Hofmann, Heath; Mackin, Michael; Santiago, Walter; Jansen, Ralph

    2001-01-01

    This paper describes the flywheel test facility developed at the NASA Glenn Research Center with particular emphasis on the motor drive components and control. A four-pole permanent magnet synchronous machine, suspended on magnetic bearings, is controlled with a field orientation algorithm. A discussion of the estimation of the rotor position and speed from a "once around signal" is given. The elimination of small dc currents by using a concurrent stationary frame current regulator is discussed and demonstrated. Initial experimental results are presented showing the successful operation and control of the unit at speeds up to 20,000 rpm.

  14. Evaluation of initial collector field performance at the Langley Solar Building Test Facility

    NASA Technical Reports Server (NTRS)

    Boyle, R. J.; Jensen, R. N.; Knoll, R. H.

    1977-01-01

    The thermal performance of the solar collector field for the NASA Langley Solar Building Test Facility is given for October 1976 through January 1977. A 1,180 square meter solar collector field with seven collector designs helped to provide hot water for the building heating system and absorption air conditioner. The collectors were arranged in 12 rows with nominally 51 collectors per row. Heat transfer rates for each row were calculated and recorded along with sensor, insolation, and weather data every five minutes using a minicomputer. The agreement between the experimental and predicted collector efficiencies was generally within five percentage points.

  15. An assessment of RELAP5-3D using the Edwards-O'Brien Blowdown problem

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

    Tomlinson, E.T.; Aumiller, D.L.

    1999-07-01

    The RELAP5-3D (version bt) computer code was used to assess the United States Nuclear Regulatory Commission's Standard Problem 1 (Edwards-O'Brien Blowdown Test). The RELAP5-3D standard installation problem based on the Edwards-O'Brien Blowdown Test was modified to model the appropriate initial conditions and to represent the proper location of the instruments present in the experiment. The results obtained using the modified model are significantly different from the original calculation indicating the need to model accurately the experimental conditions if an accurate assessment of the calculational model is to be obtained.

  16. Evaluation of initial collector field performance at the Langley Solar Building Test Facility

    NASA Technical Reports Server (NTRS)

    Boyle, R. J.; Knoll, R. H.; Jensen, R. N.

    1977-01-01

    The thermal performance of the solar collector field for the NASA Langley Solar Building Test Facility is given for October 1976 through January 1977. An 1180 square meter solar collector field with seven collector designs helped to provide hot water for the building heating system and absorption air conditioner. The collectors were arranged in 12 rows with nominally 51 collectors per row. Heat transfer rates for each row are calculated and recorded along with sensor, insolation, and weather data every 5 minutes using a mini-computer. The agreement between the experimental and predicted collector efficiencies was generally within five percentage points.

  17. Study regarding the spline interpolation accuracy of the experimentally acquired data

    NASA Astrophysics Data System (ADS)

    Oanta, Emil M.; Danisor, Alin; Tamas, Razvan

    2016-12-01

    Experimental data processing is an issue that must be solved in almost all the domains of science. In engineering we usually have a large amount of data and we try to extract the useful signal which is relevant for the phenomenon under investigation. The criteria used to consider some points more relevant then some others may take into consideration various conditions which may be either phenomenon dependent, or general. The paper presents some of the ideas and tests regarding the identification of the best set of criteria used to filter the initial set of points in order to extract a subset which best fits the approximated function. If the function has regions where it is either constant, or it has a slow variation, fewer discretization points may be used. This means to create a simpler solution to process the experimental data, keeping the accuracy in some fair good limits.

  18. An integrated approach to model strain localization bands in magnesium alloys

    NASA Astrophysics Data System (ADS)

    Baxevanakis, K. P.; Mo, C.; Cabal, M.; Kontsos, A.

    2018-02-01

    Strain localization bands (SLBs) that appear at early stages of deformation of magnesium alloys have been recently associated with heterogeneous activation of deformation twinning. Experimental evidence has demonstrated that such "Lüders-type" band formations dominate the overall mechanical behavior of these alloys resulting in sigmoidal type stress-strain curves with a distinct plateau followed by pronounced anisotropic hardening. To evaluate the role of SLB formation on the local and global mechanical behavior of magnesium alloys, an integrated experimental/computational approach is presented. The computational part is developed based on custom subroutines implemented in a finite element method that combine a plasticity model with a stiffness degradation approach. Specific inputs from the characterization and testing measurements to the computational approach are discussed while the numerical results are validated against such available experimental information, confirming the existence of load drops and the intensification of strain accumulation at the time of SLB initiation.

  19. Experimental Investigation of Magnesium Powder Combustion With C02 for Mars Ascent Applications

    NASA Technical Reports Server (NTRS)

    Foote, John P.; Litchford, Ronald J.

    2005-01-01

    Combustion of metals with CO2 has been identified as a possible propellant for Mars ascent applications. CO2 could be condensed from the Martian atmosphere, reducing the amount of propellant that must be transported from Earth. An attractive feature of this approach compared to other in situ propellant concepts is that no chemical processing on Mars is required. Magnesium has been identified as the most promising metal for this application because it ignites and burns easily in CO2. Preliminary systems studies indicate a 2 to 1 delivered mass advantage for Mg ascent propulsion using in situ C02, as compared to a conventional storable propellant system. The Propulsion Research Center at MSFC is undertaking an experimental investigation of magnesium powder combustion with CO2 in order to provide fundamental data on the combustion performance of Mg powder + CO2 mixtures needed to assess the feasibility of developing a practical Mg powder + CO2 rocket engine. Initial combustion experiments will be carried out in a small scale atmospheric pressure dump combustor. Effects of varying the Mg particle size, firing rate and O/F ratio on combustion stability and efficiency will be investigated. The combustion process will be characterized by optical flame measurements and extraction of combustion product samples. The experimental facility is currently being prepared and combustion experiments will begin during the first quarter of 2005. The final paper will describe the test facility and initial experimental results.

  20. Overview of Advanced Space Propulsion Activities in the Space Environmental Effects Team at MSFC

    NASA Technical Reports Server (NTRS)

    Edwards, David; Carruth, Ralph; Vaughn, Jason; Schneider, Todd; Kamenetzky, Rachel; Gray, Perry

    2000-01-01

    Exploration of our solar system, and beyond, requires spacecraft velocities beyond our current technological level. Technologies addressing this limitation are numerous. The Space Environmental Effects (SEE) Team at the Marshall Space Flight Center (MSFC) is focused on three discipline areas of advanced propulsion; Tethers, Beamed Energy, and Plasma. This presentation will give an overview of advanced propulsion related activities in the Space Environmental Effects Team at MSFC. Advancements in the application of tethers for spacecraft propulsion were made while developing the Propulsive Small Expendable Deployer System (ProSEDS). New tether materials were developed to meet the specifications of the ProSEDS mission and new techniques had to be developed to test and characterize these tethers. Plasma contactors were developed, tested and modified to meet new requirements. Follow-on activities in tether propulsion include the Air-SEDS activity. Beamed energy activities initiated with an experimental investigation to quantify the momentum transfer subsequent to high power, 5J, ablative laser interaction with materials. The next step with this experimental investigation is to quantify non-ablative photon momentum transfer. This step was started last year and will be used to characterize the efficiency of solar sail materials before and after exposure to Space Environmental Effects (SEE). Our focus with plasma, for propulsion, concentrates on optimizing energy deposition into a magnetically confined plasma and integration of measurement techniques for determining plasma parameters. Plasma confinement is accomplished with the Marshall Magnetic Mirror (M3) device. Initial energy coupling experiments will consist of injecting a 50 amp electron beam into a target plasma. Measurements of plasma temperature and density will be used to determine the effect of changes in magnetic field structure, beam current, and gas species. Experimental observations will be compared to predictions from computer modeling.

  1. Assays of homeopathic remedies in rodent behavioural and psychopathological models.

    PubMed

    Bellavite, Paolo; Magnani, Paolo; Marzotto, Marta; Conforti, Anita

    2009-10-01

    The first part of this paper reviews the effects of homeopathic remedies on several models of anxiety-like behaviours developed and described in rodents. The existing literature in this field comprises some fifteen exploratory studies, often published in non-indexed and non-peer-reviewed journals. Only a few results have been confirmed by multiple laboratories, and concern Ignatia, Gelsemium, Chamomilla (in homeopathic dilutions/potencies). Nevertheless, there are some interesting results pointing to the possible efficacy of other remedies, and confirming a statistically significant effect of high dilutions of neurotrophic molecules and antibodies. In the second part of this paper we report some recent results obtained in our laboratory, testing Aconitum, Nux vomica, Belladonna, Argentum nitricum, Tabacum (all 5CH potency) and Gelsemium (5, 7, 9 and 30CH potencies) on mice using ethological models of behaviour. The test was performed using coded drugs and controls in double blind (operations and calculations). After an initial screening that showed all the tested remedies (except for Belladonna) to have some effects on the behavioural parameters (light-dark test and open-field test), but with high experimental variability, we focused our study on Gelsemium, and carried out two complete series of experiments. The results showed that Gelsemium had several effects on the exploratory behaviour of mice, which in some models were highly statistically significant (p < 0.001), in all the dilutions/dynamizations used, but with complex differences according to the experimental conditions and test performed. Finally, some methodological issues of animal research in this field of homeopathy are discussed. The "Gelsemium model" - encompassing experimental studies in vitro and in vivo from different laboratories and with different methods, including significant effects of its major active principle gelsemine - may play a pivotal rule for investigations on other homeopathic remedies.

  2. Development of multilayer perceptron networks for isothermal time temperature transformation prediction of U-Mo-X alloys

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

    Johns, Jesse M.; Burkes, Douglas

    In this work, a multilayered perceptron (MLP) network is used to develop predictive isothermal time-temperature-transformation (TTT) models covering a range of U-Mo binary and ternary alloys. The selected ternary alloys for model development are U-Mo-Ru, U-Mo-Nb, U-Mo-Zr, U-Mo-Cr, and U-Mo-Re. These model’s ability to predict 'novel' U-Mo alloys is shown quite well despite the discrepancies between literature sources for similar alloys which likely arise from different thermal-mechanical processing conditions. These models are developed with the primary purpose of informing experimental decisions. Additional experimental insight is necessary in order to reduce the number of experiments required to isolate ideal alloys. Thesemore » models allow test planners to evaluate areas of experimental interest; once initial tests are conducted, the model can be updated and further improve follow-on testing decisions. The model also improves analysis capabilities by reducing the number of data points necessary from any particular test. For example, if one or two isotherms are measured during a test, the model can construct the rest of the TTT curve over a wide range of temperature and time. This modeling capability reduces the cost of experiments while also improving the value of the results from the tests. The reduced costs could result in improved material characterization and therefore improved fundamental understanding of TTT dynamics. As additional understanding of phenomena driving TTTs is acquired, this type of MLP model can be used to populate unknowns (such as material impurity and other thermal mechanical properties) from past literature sources.« less

  3. Development of small solid rocket boosters for the ILR-33 sounding rocket

    NASA Astrophysics Data System (ADS)

    Nowakowski, Pawel; Okninski, Adam; Pakosz, Michal; Cieslinski, Dawid; Bartkowiak, Bartosz; Wolanski, Piotr

    2017-09-01

    This paper gives an overview of the development of a 6000 Newton-class solid rocket motor for suborbital applications. The design configuration and results of interior ballistics calculations are given. The initial use of the motor as the main propulsion system of the H1 experimental in-flight test platform, within the Polish Small Sounding Rocket Program, is presented. Comparisons of theoretical and experimental performance are shown. Both on-ground and in-flight tests are discussed. A novel composite-case manufacturing technology, which enabled to reach high propellant mass fractions, was validated and significant cost-reductions were achieved. This paper focuses on the process of adapting the design for use as the booster stage of the ILR-33 sounding rocket, under development at the Institute of Aviation in Warsaw, Poland. Parallel use of two of the flight-proven rocket motors along with the main stage is planned. The process of adapting the rocket motor for booster application consists of stage integration, aerothermodynamics and reliability analyses. The separation mechanism and environmental impact are also discussed within this paper. Detailed performance analysis with focus on propellant grain geometry is provided. The evolution of the design since the first flights of the H1 rocket is covered and modifications of the manufacturing process are described. Issues of simultaneous ignition of two motors and their non-identical performance are discussed. Further applications and potential for future development are outlined. The presented results are based on the initial work done by the Rocketry Group of the Warsaw University of Technology Students' Space Association. The continuation of the Polish Small Sounding Rocket Program on a larger scale at the Institute of Aviation proves the value of the outcomes of the initial educational project.

  4. X-34 Experimental Aeroheating at Mach 6 and 10

    NASA Technical Reports Server (NTRS)

    Berry, Scott A.; Horvath, Thomas J.; DiFulvio, Michael; Glass, Christopher; Merski, N. Ronald

    1998-01-01

    Critical technologies are being developed to support the goals of the NASA Office of Aeronautics and Space Transportation Technology Access to Space initiative for next-generation reusable space transportation systems. From the perspective of aerothermodynamic performance throughout the flight trajectory, the Reusable Launch Vehicle program incorporates conceptual analysis, ground-based testing, and computational fluid dynamics to provide flyable suborbital flight demonstrator vehicles. This report provides an overview of the hypersonic aeroheating wind tunnel test program conducted at the NASA Langley Research Center in support of one of these vehicles, the X-34 small reusable technology demonstrator program. Global surface heat transfer images, surface streamline patterns, and shock shapes were measured on 0.0153- and 0.0183-scale models of proposed X-34 flight vehicles at Mach 6 and 10 in air. The primary parametrics that were investigated include angles-of-attack from 0 to 35 deg. and freestream unit Reynolds numbers from 0.5 to 8 million per foot (which was sufficient to produce laminar, transitional, and turbulent heating data), both with and without control surface deflections. Comparisons of the experimental data to computational predictions are included, along with a discussion of the implications of some of the experimental flow features for the flight vehicle.

  5. Performance of Oil Pumping Rings: An Analytical and Experimental Study

    NASA Technical Reports Server (NTRS)

    Eusepi, M. W.; Walowit, J. A.; Pinkus, O.; Holmes, P.

    1986-01-01

    A steady-state design computer program was developed to predict the performance of pumping rings as functions of geometry, applied loading, speed, ring modulus, and fluid viscosity. Additional analyses were developed to predict transient behavior of the ring and the effects of temperature rises occurring in the hydrodynamic film between the ring and shaft. The analysis was initially compared with previous experimental data and then used to design additional rings for further testing. Tests were performed with Rulon, carbon-graphite, and babbit rings. The design analysis was used to size all of the rings and to select the ranges of clearances, thickness, and loading. Although full quantitative agreement was lacking, relative agreement existed in that rings that were predicted to perform well theoretically, generally performed well experimentally. Some causes for discrepanices between theory and experiment are believed to be due to starvation, leakage past the secondary seal at high pressures, and uncertainties in the small clearances and local inlet temperatures to the pumping ring. A separate preliminary analysis was performed for a pumping Leningrader seal. This anlaysis can be used to predict the film thickness and flow rate thr ough the seal as a function of pressure, speed, loading, and geometry.

  6. Liquid Transfer Cryogenic Test Facility: Initial hydrogen and nitrogen no-vent fill data

    NASA Astrophysics Data System (ADS)

    Moran, Matthew E.; Nyland, Ted W.; Papell, S. Stephen

    1990-03-01

    The Liquid Transfer Cryogenic Test Facility is a versatile testbed for ground-based cryogenic fluid storage, handling, and transfer experimentation. The test rig contains two well instrumented tanks, and a third interchangeable tank, designed to accommodate liquid nitrogen or liquid hydrogen testing. The internal tank volumes are approx. 18, 5, and 1.2 cu. ft. Tank pressures can be varied from 2 to 30 psia. Preliminary no vent fill tests with nitrogen and hydrogen were successfully completed with the test rig. Initial results indicate that no vent fills of nitrogen above 90 percent full are achievable using this test configuration, in a 1-g environment, and with inlet liquid temperatures as high as 143 R, and an average tank wall temperature of nearly 300 R. This inlet temperature corresponds to a saturation pressure of 19 psia for nitrogen. Hydrogen proved considerably more difficult to transfer between tanks without venting. The highest temperature conditions resulting in a fill level greater than 90 percent were with an inlet liquid temperature of 34 R, and an estimated tank wall temperature of slightly more than 100 R. Saturation pressure for hydrogen at this inlet temperature is 10 psia. All preliminary no vent fill tests were performed with a top mounted full cone nozzle for liquid injection. The nozzle produces a 120 degree conical droplet spray at a differential pressure of 10 psi. Pressure in the receiving tank was held to less than 30 psia for all tests.

  7. Liquid Transfer Cryogenic Test Facility: Initial hydrogen and nitrogen no-vent fill data

    NASA Technical Reports Server (NTRS)

    Moran, Matthew E.; Nyland, Ted W.; Papell, S. Stephen

    1990-01-01

    The Liquid Transfer Cryogenic Test Facility is a versatile testbed for ground-based cryogenic fluid storage, handling, and transfer experimentation. The test rig contains two well instrumented tanks, and a third interchangeable tank, designed to accommodate liquid nitrogen or liquid hydrogen testing. The internal tank volumes are approx. 18, 5, and 1.2 cu. ft. Tank pressures can be varied from 2 to 30 psia. Preliminary no vent fill tests with nitrogen and hydrogen were successfully completed with the test rig. Initial results indicate that no vent fills of nitrogen above 90 percent full are achievable using this test configuration, in a 1-g environment, and with inlet liquid temperatures as high as 143 R, and an average tank wall temperature of nearly 300 R. This inlet temperature corresponds to a saturation pressure of 19 psia for nitrogen. Hydrogen proved considerably more difficult to transfer between tanks without venting. The highest temperature conditions resulting in a fill level greater than 90 percent were with an inlet liquid temperature of 34 R, and an estimated tank wall temperature of slightly more than 100 R. Saturation pressure for hydrogen at this inlet temperature is 10 psia. All preliminary no vent fill tests were performed with a top mounted full cone nozzle for liquid injection. The nozzle produces a 120 degree conical droplet spray at a differential pressure of 10 psi. Pressure in the receiving tank was held to less than 30 psia for all tests.

  8. Artificial neural network (ANN) approach for modeling of Pb(II) adsorption from aqueous solution by Antep pistachio (Pistacia Vera L.) shells.

    PubMed

    Yetilmezsoy, Kaan; Demirel, Sevgi

    2008-05-30

    A three-layer artificial neural network (ANN) model was developed to predict the efficiency of Pb(II) ions removal from aqueous solution by Antep pistachio (Pistacia Vera L.) shells based on 66 experimental sets obtained in a laboratory batch study. The effect of operational parameters such as adsorbent dosage, initial concentration of Pb(II) ions, initial pH, operating temperature, and contact time were studied to optimise the conditions for maximum removal of Pb(II) ions. On the basis of batch test results, optimal operating conditions were determined to be an initial pH of 5.5, an adsorbent dosage of 1.0 g, an initial Pb(II) concentration of 30 ppm, and a temperature of 30 degrees C. Experimental results showed that a contact time of 45 min was generally sufficient to achieve equilibrium. After backpropagation (BP) training combined with principal component analysis (PCA), the ANN model was able to predict adsorption efficiency with a tangent sigmoid transfer function (tansig) at hidden layer with 11 neurons and a linear transfer function (purelin) at output layer. The Levenberg-Marquardt algorithm (LMA) was found as the best of 11 BP algorithms with a minimum mean squared error (MSE) of 0.000227875. The linear regression between the network outputs and the corresponding targets were proven to be satisfactory with a correlation coefficient of about 0.936 for five model variables used in this study.

  9. Poly-MVA attenuates 7,12- dimethylbenz[a]anthracene initiated and croton oil promoted skin papilloma formation on mice skin.

    PubMed

    Veena, Ravindran K; Ajith, Thekkuttuparambil A; Janardhanan, Kainoor K; Antonawich, Francis

    2017-09-01

    Chemopreventive agents which exhibit activities such as anti-inflammation, inhibition of carcinogen induced mutagenesis and scavenging of free radical might play a decisive role in the inhibition of chemical carcinogenesis either at the initiation or promotion stage. Many synthesized palladium (Pd) complexes tested experimentally for antitumor activity are found effective. Poly-MVA is a liquid blend preparation containing B complex vitamins, ruthenium with Pd complexed with alpha lipoic acid as the major ingredients. The antitumor effect of Poly-MVA was evaluated against 7,12-dimethylbenz[a] anthracene-initiated croton oil-promoted papilloma formation on mice skin. Skin tumor was initiated with a single application of 390 nmol of DMBA in 20 µl acetone. The effect of Poly-MVA against croton oil- induced inflammation and lipid peroxidation on the mice skin was also evaluated. Topical application of Poly-MVA (100 µl, twice weekly for 18 weeks) 30 minutes prior to each croton oil application, significantly decreased the tumor incidence (11%) and the average number of tumor per animals. Application of Poly-MVA (100 µl) before croton oil significantly (p &#60; 0.05) protected the mouse skin from inflammation (36%) and lipid peroxidation (14%) when compared to the croton oil alone treated group. Experimental results indicate that Poly-MVA attenuate the tumor promoting effects of croton oil and the effect may probably be due to its anti-inflammatory and antioxidant activity.

  10. A Combined Experimental and Computational Approach to Subject-Specific Analysis of Knee Joint Laxity

    PubMed Central

    Harris, Michael D.; Cyr, Adam J.; Ali, Azhar A.; Fitzpatrick, Clare K.; Rullkoetter, Paul J.; Maletsky, Lorin P.; Shelburne, Kevin B.

    2016-01-01

    Modeling complex knee biomechanics is a continual challenge, which has resulted in many models of varying levels of quality, complexity, and validation. Beyond modeling healthy knees, accurately mimicking pathologic knee mechanics, such as after cruciate rupture or meniscectomy, is difficult. Experimental tests of knee laxity can provide important information about ligament engagement and overall contributions to knee stability for development of subject-specific models to accurately simulate knee motion and loading. Our objective was to provide combined experimental tests and finite-element (FE) models of natural knee laxity that are subject-specific, have one-to-one experiment to model calibration, simulate ligament engagement in agreement with literature, and are adaptable for a variety of biomechanical investigations (e.g., cartilage contact, ligament strain, in vivo kinematics). Calibration involved perturbing ligament stiffness, initial ligament strain, and attachment location until model-predicted kinematics and ligament engagement matched experimental reports. Errors between model-predicted and experimental kinematics averaged <2 deg during varus–valgus (VV) rotations, <6 deg during internal–external (IE) rotations, and <3 mm of translation during anterior–posterior (AP) displacements. Engagement of the individual ligaments agreed with literature descriptions. These results demonstrate the ability of our constraint models to be customized for multiple individuals and simultaneously call attention to the need to verify that ligament engagement is in good general agreement with literature. To facilitate further investigations of subject-specific or population based knee joint biomechanics, data collected during the experimental and modeling phases of this study are available for download by the research community. PMID:27306137

  11. Malachite Green Adsorption by Spent Coffee Grounds

    NASA Astrophysics Data System (ADS)

    Syamimie Atirah Mat, Siti; Zati Hanani Syed Zuber, Sharifah; Rahim, Siti Kartini Enche Ab; Sohaimi, Khairunissa Syairah Ahmad; Halim, Noor Amirah Abdul; Fauziah Zainudin, Nor; Aida Yusoff, Nor; Munirah Rohaizad, Nor; Hidayah Ishak, Noor; Anuar, Adilah; Sarip, Mohd Sharizan Md

    2018-03-01

    In this work, the ability of spent coffee grounds (SCG) as a low-cost adsorbent to remove malachite green (MG) from aqueous solutions was studied. Batch adsorption tests were carried out to observe the effect of various experimental parameters such as contact time, initial concentration of malachite green and adsorbent dosage on the removal of dye. The results obtained show that the percentage of dye removal will decreased with the increased of initial concentration of dye in the range of 50 mg/L to 250 mg/L. Besides, percentage removal of dye was also found to be increased as the contact time increased until it reached equilibrium condition. The results also showed that the adsorbent dosage in range of 0.2 g to 1.0 g is proportional to the percentage removal of malachite green dye. Study on the kinetic adsorption and isotherm adsorption has also been investigated. The adsorption isotherm data were described by Langmuir isotherm with high-correlation coefficients while the experimental data showed the pseudo-second-order kinetics model was the best model for the adsorption of MG by SCG with the coefficients of correlation R2 > 0.9978.

  12. Computational and Experimental Fluid-Structure Interaction Analysis of a High-Lift Wing with a Slat-Cove Filler for Noise Reduction

    NASA Technical Reports Server (NTRS)

    Scholten, William D.; Patterson, Ryan D.; Hartl, Darren J.; Strganac, Thomas W.; Chapelon, Quentin H. C.; Turner, Travis

    2017-01-01

    Airframe noise is a significant component of overall noise produced by transport aircraft during landing and approach (low speed maneuvers). A significant source for this noise is the cove of the leading-edge slat. The slat-cove filler (SCF) has been shown to be effective at mitigating slat noise. The objective of this work is to understand the fluid-structure interaction (FSI) behavior of a superelastic shape memory alloy (SMA) SCF in flow using both computational and physical models of a high-lift wing. Initial understanding of flow around the SCF and wing is obtained using computational fluid dynamics (CFD) analysis at various angles of attack. A framework compatible with an SMA constitutive model (implemented as a user material subroutine) is used to perform FSI analysis for multiple flow and configuration cases. A scaled physical model of the high-lift wing is constructed and tested in the Texas A&M 3 ft-by-4-foot wind tunnel. Initial validation of both CFD and FSI analysis is conducted by comparing lift, drag and pressure distributions with experimental results.

  13. Kinetics, isothermal and thermodynamics studies of electrocoagulation removal of basic dye rhodamine B from aqueous solution using steel electrodes

    NASA Astrophysics Data System (ADS)

    Adeogun, Abideen Idowu; Balakrishnan, Ramesh Babu

    2017-07-01

    Electrocoagulation was used for the removal of basic dye rhodamine B from aqueous solution, and the process was carried out in a batch electrochemical cell with steel electrodes in monopolar connection. The effects of some important parameters such as current density, pH, temperature and initial dye concentration, on the process, were investigated. Equilibrium was attained after 10 min at 30 °C. Pseudo-first-order, pseudo-second-order, Elovich and Avrami kinetic models were used to test the experimental data in order to elucidate the kinetic adsorption process; pseudo-first-order and Avrami models best fitted the data. Experimental data were analysed using six model equations: Langmuir, Freudlinch, Redlich-Peterson, Temkin, Dubinin-Radushkevich and Sips isotherms and it was found that the data fitted well with Sips isotherm model. The study showed that the process depends on current density, temperature, pH and initial dye concentration. The calculated thermodynamics parameters (Δ G°, Δ H° and Δ S°) indicated that the process is spontaneous and endothermic in nature.

  14. Synthesis and testing of ZnO nanoparticles for photo-initiation: experimental observation of two different non-migration initiators for bulk polymerization

    NASA Astrophysics Data System (ADS)

    Schmitt, M.

    2015-05-01

    The migration and transport of polymerization initiators are problematic for commercially used polymerization procedures. For example, UV printing of packaging generates products with potentially harmful components that come in contact with food. Enlarging the size of the initiator is the only way to prevent contamination, e.g., by gas phase transport. In this manuscript, the synthesis and advanced and full analyses of novel nanoparticle-based types of non-migration, fragmenting and non-fragmenting photo-initiators will be presented in detail. This study introduces non-fragmenting/``Norrish type II'' and fragmenting/``Norrish type I'' ZnO nanoparticle-based initiators and compares them with two commercial products, a ``Norrish type I'' initiator and a ``Norrish type II'' initiator. Therefore, inter alia, the recently developed analysis involves examining the solidification by UV-vis and the double bond content by Raman. Irradiation is performed using absolute and spectrally calibrated xenon flash lights. A novel procedure for absolute and spectral calibration of such light sources is also presented. The non-optimized ``Norrish type II'' particle-based initiator is already many times faster than benzophenone, which is a molecular initiator of the same non-fragmenting type. This experimentally observed difference in reactive particle-based systems without co-initiators is unexpected. Co-initiators are normally an additional molecular species, which leads to migration problems. The discovery of significant initiation potential resulting in a very well-dispersed organic-inorganic hybrid material suggests a new field of research opportunities at the interface of physical chemistry, polymer chemistry and engineering science, with enormous value for human health.The migration and transport of polymerization initiators are problematic for commercially used polymerization procedures. For example, UV printing of packaging generates products with potentially harmful components that come in contact with food. Enlarging the size of the initiator is the only way to prevent contamination, e.g., by gas phase transport. In this manuscript, the synthesis and advanced and full analyses of novel nanoparticle-based types of non-migration, fragmenting and non-fragmenting photo-initiators will be presented in detail. This study introduces non-fragmenting/``Norrish type II'' and fragmenting/``Norrish type I'' ZnO nanoparticle-based initiators and compares them with two commercial products, a ``Norrish type I'' initiator and a ``Norrish type II'' initiator. Therefore, inter alia, the recently developed analysis involves examining the solidification by UV-vis and the double bond content by Raman. Irradiation is performed using absolute and spectrally calibrated xenon flash lights. A novel procedure for absolute and spectral calibration of such light sources is also presented. The non-optimized ``Norrish type II'' particle-based initiator is already many times faster than benzophenone, which is a molecular initiator of the same non-fragmenting type. This experimentally observed difference in reactive particle-based systems without co-initiators is unexpected. Co-initiators are normally an additional molecular species, which leads to migration problems. The discovery of significant initiation potential resulting in a very well-dispersed organic-inorganic hybrid material suggests a new field of research opportunities at the interface of physical chemistry, polymer chemistry and engineering science, with enormous value for human health. Electronic supplementary information (ESI) available: Multiple additional figures and images concerning the synthesis, characterization, data evaluation, TEMs and ESR spectra are available free of charge. See DOI: 10.1039/c5nr00850f

  15. The effect of a dominant initial single mode on the Kelvin–Helmholtz instability evolution: New insights on previous experimental results

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

    Shimony, Assaf; Shvarts, Dov; Malamud, Guy

    2016-04-12

    This paper brings new insights on an experiment, measuring the Kelvin–Helmholtz (KH) instability evolution, performed on the OMEGA-60 laser facility. Experimental radiographs show that the initial seed perturbations in the experiment are of multimode spectrum with a dominant single-mode of 16 μm wavelength. In single-mode-dominated KH instability flows, the mixing zone (MZ) width saturates to a constant value comparable to the wavelength. However, the experimental MZ width at late times has exceeded 100 μm, an order of magnitude larger. In this work, we use numerical simulations and a statistical model in order to investigate the vortex dynamics of the KHmore » instability for the experimental initial spectrum. Here, we conclude that the KH instability evolution in the experiment is dominated by multimode, vortex-merger dynamics, overcoming the dominant initial mode.« less

  16. Experimental and analytical study of cryogenic propellant boiloff to develop and verify alternate pressurization concepts for Space Shuttle external tank using a scaled down tank

    NASA Technical Reports Server (NTRS)

    Akyuzlu, K. M.; Jones, S.; Meredith, T.

    1993-01-01

    Self pressurization by propellant boiloff is experimentally studied as an alternate pressurization concept for the Space Shuttle external tank (ET). The experimental setup used in the study is an open flow system which is composed of a variable area test tank and a recovery tank. The vacuum jacketed test tank is geometrically similar to the external LOx tank for the Space Shuttle. It is equipped with instrumentation to measure the temperature and pressure histories within the liquid and vapor, and viewports to accommodate visual observations and Laser-Doppler Anemometry measurements of fluid velocities. A set of experiments were conducted using liquid Nitrogen to determine the temperature stratification in the liquid and vapor, and pressure histories of the vapor during sudden and continuous depressurization for various different boundary and initial conditions. The study also includes the development and calibration of a computer model to simulate the experiments. This model is a one-dimensional, multi-node type which assumes the liquid and the vapor to be under non-equilibrium conditions during the depressurization. It has been tested for a limited number of cases. The preliminary results indicate that the accuracy of the simulations is determined by the accuracy of the heat transfer coefficients for the vapor and the liquid at the interface which are taken to be the calibration parameters in the present model.

  17. Reconnaissance blind multi-chess: an experimentation platform for ISR sensor fusion and resource management

    NASA Astrophysics Data System (ADS)

    Newman, Andrew J.; Richardson, Casey L.; Kain, Sean M.; Stankiewicz, Paul G.; Guseman, Paul R.; Schreurs, Blake A.; Dunne, Jeffrey A.

    2016-05-01

    This paper introduces the game of reconnaissance blind multi-chess (RBMC) as a paradigm and test bed for understanding and experimenting with autonomous decision making under uncertainty and in particular managing a network of heterogeneous Intelligence, Surveillance and Reconnaissance (ISR) sensors to maintain situational awareness informing tactical and strategic decision making. The intent is for RBMC to serve as a common reference or challenge problem in fusion and resource management of heterogeneous sensor ensembles across diverse mission areas. We have defined a basic rule set and a framework for creating more complex versions, developed a web-based software realization to serve as an experimentation platform, and developed some initial machine intelligence approaches to playing it.

  18. The UMLS Knowledge Sources: Tools for Building Better User Interfaces

    PubMed Central

    Lindberg, Donald A. B.; Humphreys, Betsy L.

    1990-01-01

    The current focus of the National Library of Medicine's Unified Medical Language System (UMLS) project is the development, testing, and evaluation of the first versions of three new knowledge sources: the Metathesaurus, the Semantic Network, and the Information Sources Map. These three knowledge sources can be used by interface programs to conduct an intelligent interaction with the user and to make the conceptual link between the user's question and relevant machine-readable information. NLM is providing experimental copies of the initial versions of the UMLS knowledge sources in exchange for feedback on ways they can and should be improved. The hope is that the results of such experimentation will provide both immediate improvements in biomedical information service and useful suggestions for enhancements to the UMLS.

  19. Thermo-mechanical modeling of the gas-tungsten-arc (GTA) welding process

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

    Duncan, D.B.

    1980-01-18

    A fundamental study of gas-tungsten-arc (GTA) welding was undertaken. This was initiated with a review of the GTA welding process which lead to the decision to focus experimental and analytical efforts on stationary welds on a pure material. Pure nickel was selected for the test material. Temperature, strain, and distortion measurements were made during the formation of spot welds on circular plates. Transient thermal data were obtained with thermocouples, a radiation pyrometer, and from motion pictures. Local strain was observed qualitatively from Moire interference fringe patterns. Distortion during welding was measured with displacement gages and residual distortion with a profilometer.more » Experimental measurements are compared with predictions of thermal and mechanical finite element codes.« less

  20. Molecular modeling and biological evaluation of 2-N,N-dimethylaminecyclohexyl 1-N‧,N‧-dimethylcarbamate isomers and their methylsulfate salts as cholinesterases inhibitors

    NASA Astrophysics Data System (ADS)

    Bocca, Cleverson C.; Rittner, Roberto; Höehr, Nelci F.; Pinheiro, Glaucia M. S.; Abiko, Layara A.; Basso, Ernani A.

    2010-11-01

    This work presents a detailed theoretical and experimental study on the inhibitory properties of 2- N,N-dimethylaminecyclohexyl 1- N',N'-dimethylcarbamate isomers and their methylsulfate salts against the cholinesterases enzymes. The in vitro inhibition test performed by the Ellman's method showed that the salt form compounds were more active than the neutral ones in cholinesterases inhibition. The trans salt showed good selectivity towards the inhibition of erythrocyte cholinesterase with a maximum limit around 90% and 55% for the plasma cholinesterase inhibition. Molecular modeling, docking and experimental results performed in this study showed to be important initial steps toward the development of a novel pharmaceuticals in the fight against Alzheimer's disease.

  1. Experimental Evaluation of a Water Shield for a Surface Power Reactor

    NASA Technical Reports Server (NTRS)

    Pearson, J. B.; Reid, R.; Sadasivan, P.; Stewart, E.

    2007-01-01

    A water based shielding system is being investigated for use on initial lunar surface power systems. The use of water may lower overall cost (as compared to development cost for other materials) and simplify operations in the setup and handling. The thermal hydraulic performance of the shield is of significant interest. The mechanism for transferring heat through the shield is natural convection. A representative lunar surface reactor design is evaluated at various power levels in the Water Shield Testbed (WST) at the NASA Marshall Space Flight Center. The evaluation compares the experimental data from the WST to CFD models. Performance of a water shield on the lunar surface is predicted by CFD models anchored to test data, and by matching relevant dimensionless parameters.

  2. Effect of teaching mathematics using GeoGebra on students' with dissimilar spatial visualisation

    NASA Astrophysics Data System (ADS)

    Bakar, Kamariah Abu; Ayub, Ahmad Fauzi Mohd; Tarmizi, Rohani Ahmad; Luan, Wong Su

    2015-10-01

    This study examined the effects of GeoGebra on mathematics performance of students with different spatial visualization. A qusai-experimental, pretest-posttest control group design was conducted. A total of 71 students from two intact groups were involved in the study. They were in two groups and each group was randonly assigned to the experimental group (36 students) and control group (35 students). A spatial visual test to identify students with high or low visualization, and a mathematics performance pre-test were administered at the initial stage of this study. A post-test was administered after 12 weeks of treatment using GeoGebra. Analyses of Covarion (ANCOVA) was used to adjust for the pre-test score. Findings showed that the group with access to GeoGebra achieved significantly better test scores in the posttest as compared to the group which followed the traditional teaching method. A two-way ANCOVA used to analyse the effect of students' spatial visualization on post-test performance showed that there was no effect. The results from this study suggested that using GeoGebra had helped the students to score better in the posttest. However, there is no significance difference on mathematics performances on students with difference types of spatial visualisastion. This study indicates that GeoGebra is useful in enhancing the teaching and learning of mathematics.

  3. Inquiry-Based Integrated Science Education: Implementation of Local Content “Soil Washing” Project To Improve Junior High School Students’ Environmental Literacy

    NASA Astrophysics Data System (ADS)

    Syifahayu

    2017-02-01

    The study was conducted based on teaching and learning problems led by conventional method that had been done in the process of learning science. It gave students lack opportunities to develop their competence and thinking skills. Consequently, the process of learning science was neglected. Students did not have opportunity to improve their critical attitude and creative thinking skills. To cope this problem, the study was conducted using Project-Based Learning model through inquiry-based science education about environment. The study also used an approach called Sains Lingkungan and Teknologi masyarakat - “Saling Temas” (Environmental science and Technology in Society) which promoted the local content in Lampung as a theme in integrated science teaching and learning. The study was a quasi-experimental with pretest-posttest control group design. Initially, the subjects were given a pre-test. The experimental group was given inquiry learning method while the control group was given conventional learning. After the learning process, the subjects of both groups were given post-test. Quantitative analysis was performed using the Mann-Whitney U-test and also a qualitative descriptive. Based on the result, environmental literacy skills of students who get inquiry learning strategy, with project-based learning model on the theme soil washing, showed significant differences. The experimental group is better than the control group. Data analysis showed the p-value or sig. (2-tailed) is 0.000 <α = 0.05 with the average N-gain of experimental group is 34.72 and control group is 16.40. Besides, the learning process becomes more meaningful.

  4. Effects of Laughing Training on Stress Levels in Thai Private Office Workers.

    PubMed

    Chuchuen, Uayart; Pampiansil, Pornphun; Busarakumtragul, Panaree

    2015-10-01

    Laughing is a kind of well known alternative medicine used to treat stressful persons or depressive patients to relax. The laughing program used in this study was initially designed by Thai psychiatrists. It consists of deep diaphragmatic breathing exercises, voice expression, facial expression exercises and aerobic exercises, which are expected to promote good health. To evaluate the effects of the laughing training on stress levels in Thai private office workers. Thirty-eight subjects whose age 25-60 years were recruited to enroll in this program. They were randomly divided into two groups: 20 people for the experimental group and 18 persons for the control group. The experimental subjects participated in laughing program for 3 days/week, 60 minutes/day for 8 consecutive weeks. The program took place from June to July 2013. The level of stress was assessed using the Suanprung stress test-60 (SPST-60). The data were analyzed by descriptive statistics, t-test dependent and t-test independent with p < 0.05 considered significant. After they joined the laughing program, no significant difference was found in the mean scores of the level of stress between the control and experimental groups. However, the sensitivities to the arousal events in the experimental group had a tendency to decrease. Laughing training may be used as a tool to promote better health. There was no significant difference in the stress levels after the program was ended except a decrement tendency in the sensitivities to the arousal events. For further study, duration and intensity of the course may be adjusted for a more effective training program.

  5. Control of Growth Rate by Initial Substrate Concentration at Values Below Maximum Rate

    PubMed Central

    Gaudy, Anthony F.; Obayashi, Alan; Gaudy, Elizabeth T.

    1971-01-01

    The hyperbolic relationship between specific growth rate, μ, and substrate concentration, proposed by Monod and used since as the basis for the theory of steady-state growth in continuous-flow systems, was tested experimentally in batch cultures. Use of a Flavobacterium sp. exhibiting a high saturation constant for growth in glucose minimal medium allowed direct measurement of growth rate and substrate concentration throughout the growth cycle in medium containing a rate-limiting initial concentration of glucose. Specific growth rates were also measured for a wide range of initial glucose concentrations. A plot of specific growth rate versus initial substrate concentration was found to fit the hyperbolic equation. However, the instantaneous relationship between specific growth rate and substrate concentration during growth, which is stated by the equation, was not observed. Well defined exponential growth phases were developed at initial substrate concentrations below that required for support of the maximum exponential growth rate and a constant doubling time was maintained until 50% of the substrate had been used. It is suggested that the external substrate concentration initially present “sets” the specific growth rate by establishing a steady-state internal concentration of substrate, possibly through control of the number of permeation sites. PMID:5137579

  6. Brief report: Into the wild? How a film can change adolescents' values.

    PubMed

    Döring, Anna K; Hillbrink, Alessa

    2015-04-01

    In adolescence, behavior and attitudes are constantly rethought and value priorities are established. Still, there is hardly any research addressing how values are shaped throughout this sensitive period. We employed an experimental design, testing whether adolescents' values can be influenced by exposure to a film. In our study, 154 German adolescents (80 females, ages 13-15) were randomly assigned to an experimental group that watched excerpts from the film "Into the wild" or to a control group. Value change was assessed in a pre-post-test design with a one-week interval. As hypothesized, values changed in the direction of those displayed by the film's protagonist: Universalism values increased significantly and conformity values decreased significantly as compared to the control group. Our findings suggest that single exposure to a film may initiate value change, indicating that not only major live events, but also everyday experiences significantly affect adolescents' values. Copyright © 2015 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

  7. Detonation propagation in a high loss configuration

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

    Jackson, Scott I; Shepherd, Joseph E

    2009-01-01

    This work presents an experimental study of detonation wave propagation in tubes with inner diameters (ID) comparable to the mixture cell size. Propane-oxygen mixtures were used in two test section tubes with inner diameters of 1.27 mm and 6.35 mm. For both test sections, the initial pressure of stoichiometric mixtures was varied to determine the effect on detonation propagation. For the 6.35 mm tube, the equivalence ratio {phi} (where the mixture was {phi} C{sub 3}H{sub 8} + 50{sub 2}) was also varied. Detonations were found to propagate in mixtures with cell sizes as large as five times the diameter ofmore » the tube. However, under these conditions, significant losses were observed, resulting in wave propagation velocities as slow as 40% of the CJ velocity U{sub CJ}. A review of relevant literature is presented, followed by experimental details and data. Observed velocity deficits are predicted using models that account for boundary layer growth inside detonation waves.« less

  8. Effects of geometrical parameters on thermal-hydraulic performance of wavy microtube

    NASA Astrophysics Data System (ADS)

    Khoshvaght-Aliabadi, Morteza; Chamanroy, Zohreh

    2018-03-01

    Laminar flow and heat transfer characteristics of water flow through wavy microtubes (WMTs) with different values of wave length ( l) and wave amplitude ( a) are investigated experimentally. The tested WMTs are fabricated from copper microtube with the internal diameter of 914 μm. Experiments encompass the Reynolds numbers from 640 to 1950. In order to validate the experimental setup and create a base line for comparison, initial tests are also carried out for a straight microtube. The results show that both the heat transfer coefficient and the pressure drop are strongly affected by the studied geometrical factors. For a given Reynolds number, these parameters increase as the wave length decreases and the wave amplitude increases. However, in the studied ranges, the effect of wave amplitude is more than that of wave length. A considerable thermal-hydraulic factor of 1.78 is obtained for a WMT with l = 14.3 mm and a = 6 mm. Finally, correlations are developed to predict the Colburn factor and friction factor of water flow in the WMTs.

  9. Initial comparison of single cylinder Stirling engine computer model predictions with test results

    NASA Technical Reports Server (NTRS)

    Tew, R. C., Jr.; Thieme, L. G.; Miao, D.

    1979-01-01

    A NASA developed digital computer code for a Stirling engine, modelling the performance of a single cylinder rhombic drive ground performance unit (GPU), is presented and its predictions are compared to test results. The GPU engine incorporates eight regenerator/cooler units and the engine working space is modelled by thirteen control volumes. The model calculates indicated power and efficiency for a given engine speed, mean pressure, heater and expansion space metal temperatures and cooler water inlet temperature and flow rate. Comparison of predicted and observed powers implies that the reference pressure drop calculations underestimate actual pressure drop, possibly due to oil contamination in the regenerator/cooler units, methane contamination in the working gas or the underestimation of mechanical loss. For a working gas of hydrogen, the predicted values of brake power are from 0 to 6% higher than experimental values, and brake efficiency is 6 to 16% higher, while for helium the predicted brake power and efficiency are 2 to 15% higher than the experimental.

  10. Extended analysis of Skylab experiment M558 data

    NASA Technical Reports Server (NTRS)

    Ukanwa, A. O.

    1976-01-01

    A careful review of the data from Skylab M558 was made in an effort to explain the apparent anomaly of the existence of radial concentration gradients whereas none should bave been observed. The very close modelling of the experimental axial concentration profiles by the unsteady-state one-dimensional solution of Fick's Law of self-diffusion in liquid zinc, and the condition of initial uniform concentration in the radioactive pellet portion of the experimental specimens would have precluded the appearance of such radial concentration gradients. Statistical analyses were used to test the significance of the observed deviation from radial-concentration homogeneity. A student t-distribution test of significance showed that, at 90% or even at 80% level of significance, there were no significant deviations from uniformity in radial concentrations. It was also concluded that the two likely causes of any deviation that existed were the zinc to zinc-65 bonding procedure and surface phenomena such as surface tension and capillary action.

  11. An Experimental Realization of a Chaos-Based Secure Communication Using Arduino Microcontrollers.

    PubMed

    Zapateiro De la Hoz, Mauricio; Acho, Leonardo; Vidal, Yolanda

    2015-01-01

    Security and secrecy are some of the important concerns in the communications world. In the last years, several encryption techniques have been proposed in order to improve the secrecy of the information transmitted. Chaos-based encryption techniques are being widely studied as part of the problem because of the highly unpredictable and random-look nature of the chaotic signals. In this paper we propose a digital-based communication system that uses the logistic map which is a mathematically simple model that is chaotic under certain conditions. The input message signal is modulated using a simple Delta modulator and encrypted using a logistic map. The key signal is also encrypted using the same logistic map with different initial conditions. In the receiver side, the binary-coded message is decrypted using the encrypted key signal that is sent through one of the communication channels. The proposed scheme is experimentally tested using Arduino shields which are simple yet powerful development kits that allows for the implementation of the communication system for testing purposes.

  12. Tensile Properties of Polymeric Matrix Composites Subjected to Cryogenic Environments

    NASA Technical Reports Server (NTRS)

    Whitley, Karen S.; Gates, Thomas S.

    2004-01-01

    Polymer matrix composites (PMC s) have seen limited use as structural materials in cryogenic environments. One reason for the limited use of PMC s in cryogenic structures is a design philosophy that typically requires a large, validated database of material properties in order to ensure a reliable and defect free structure. It is the intent of this paper to provide an initial set of mechanical properties developed from experimental data of an advanced PMC (IM7/PETI-5) exposed to cryogenic temperatures and mechanical loading. The application of this data is to assist in the materials down-select and design of cryogenic fuel tanks for future reusable space vehicles. The details of the material system, test program, and experimental methods will be outlined. Tension modulus and strength were measured at room temperature, -196 C, and -269 C on five different laminates. These properties were also tested after aging at -186 C with and without loading applied. Microcracking was observed in one laminate.

  13. Study of the linearity of CABRI experimental ionization chambers during RIA transients

    NASA Astrophysics Data System (ADS)

    Lecerf, J.; Garnier, Y.; Hudelot, JP.; Duc, B.; Pantera, L.

    2018-01-01

    CABRI is an experimental pulse reactor operated by CEA at the Cadarache research center and funded by the French Nuclear Safety and Radioprotection Institute (IRSN). For the purpose of the CABRI International Program (CIP), operated and managed by IRSN under an OECD/NEA framework it has been refurbished since 2003 to be able to provide experiments in prototypical PWR conditions (155 bar, 300 °C) in order to study the fuel behavior under Reactivity Initiated Accident (RIA) conditions. This paper first reminds the objectives of the power commissioning tests performed on the CABRI facility. The design and location of the neutron detectors monitoring the core power are also presented. Then it focuses on the different methodologies used to calibrate the detectors and check the consistency and co-linearity of the measurements. Finally, it presents the methods used to check the linearity of the neutron detectors up to the high power levels ( 20 GW) reached during power transients. Some results obtained during the power tests campaign are also presented.

  14. A Damage Model for the Simulation of Delamination in Advanced Composites under Variable-Mode Loading

    NASA Technical Reports Server (NTRS)

    Turon, A.; Camanho, P. P.; Costa, J.; Davila, C. G.

    2006-01-01

    A thermodynamically consistent damage model is proposed for the simulation of progressive delamination in composite materials under variable-mode ratio. The model is formulated in the context of Damage Mechanics. A novel constitutive equation is developed to model the initiation and propagation of delamination. A delamination initiation criterion is proposed to assure that the formulation can account for changes in the loading mode in a thermodynamically consistent way. The formulation accounts for crack closure effects to avoid interfacial penetration of two adjacent layers after complete decohesion. The model is implemented in a finite element formulation, and the numerical predictions are compared with experimental results obtained in both composite test specimens and structural components.

  15. Recent advances and remaining challenges for the spectroscopic detection of explosive threats.

    PubMed

    Fountain, Augustus W; Christesen, Steven D; Moon, Raphael P; Guicheteau, Jason A; Emmons, Erik D

    2014-01-01

    In 2010, the U.S. Army initiated a program through the Edgewood Chemical Biological Center to identify viable spectroscopic signatures of explosives and initiate environmental persistence, fate, and transport studies for trace residues. These studies were ultimately designed to integrate these signatures into algorithms and experimentally evaluate sensor performance for explosives and precursor materials in existing chemical point and standoff detection systems. Accurate and validated optical cross sections and signatures are critical in benchmarking spectroscopic-based sensors. This program has provided important information for the scientists and engineers currently developing trace-detection solutions to the homemade explosive problem. With this information, the sensitivity of spectroscopic methods for explosives detection can now be quantitatively evaluated before the sensor is deployed and tested.

  16. NASA Low-Speed Centrifugal Compressor for Fundamental Research

    NASA Technical Reports Server (NTRS)

    Wood, J. R.; Adam, P. W.; Buggele, A. E.

    1983-01-01

    A centrifugal compressor facility being built by the NASA Lewis Research Center is described; its purpose is to obtain benchmark experimental data for internal flow code verification and modeling. The facility will be heavily instrumented with standard pressure and temperature probes and have provisions for flow visualization and laser Doppler velocimetry. The facility will accommodate rotational speeds to 2400 rpm and will be rated at pressures to 1.25 atm. The initial compressor stage for testing is geometrically and dynamically representative of modern high-performance stages with the exception of Mach number levels. Design exit tip speed for the initial stage is 500 ft/sec with a pressure ratio of 1.17. The rotor exit backsweep is 55 deg from radial.

  17. Revisiting Shock Initiation Modeling of Homogeneous Explosives

    NASA Astrophysics Data System (ADS)

    Partom, Yehuda

    2013-04-01

    Shock initiation of homogeneous explosives has been a subject of research since the 1960s, with neat and sensitized nitromethane as the main materials for experiments. A shock initiation model of homogeneous explosives was established in the early 1960s. It involves a thermal explosion event at the shock entrance boundary, which develops into a superdetonation that overtakes the initial shock. In recent years, Sheffield and his group, using accurate experimental tools, were able to observe details of buildup of the superdetonation. There are many papers on modeling shock initiation of heterogeneous explosives, but there are only a few papers on modeling shock initiation of homogeneous explosives. In this article, bulk reaction reactive flow equations are used to model homogeneous shock initiation in an attempt to reproduce experimental data of Sheffield and his group. It was possible to reproduce the main features of the shock initiation process, including thermal explosion, superdetonation, input shock overtake, overdriven detonation after overtake, and the beginning of decay toward Chapman-Jouget (CJ) detonation. The time to overtake (TTO) as function of input pressure was also calculated and compared to the experimental TTO.

  18. Tests of a low-pressure switch protected by a saturating inductor

    NASA Astrophysics Data System (ADS)

    Lauer, E. J.; Birx, D. L.

    Low pressure switches and magnetic switches were tested as possible replacements for the high pressure switches currently used on Experimental Test Accelerator and Advanced Test Accelerator. When the low pressure switch is used with a low impedance transmission line, runaway electrons form a pinched electron beam which damages the anode. The use of the low pressure switch as the first switch in the pulsed power chain was tested; i.e., the switch would be used to connect a charged capacitor across the primary winding of a step up transformer. An inductor with a saturating core is connected in series so that, initially, there is a large inductive voltage drop. As a result, there is small voltage across the switch. By the time the inductor core saturates, the switch has developed sufficient ionization so that the switch voltage remains small, even with peak current, and an electron beam is not produced.

  19. Characterization of the Goubau line for testing beam diagnostic instruments

    NASA Astrophysics Data System (ADS)

    Kim, S. Y.; Stulle, F.; Sung, C. K.; Yoo, K. H.; Seok, J.; Moon, K. J.; Choi, C. U.; Chung, Y.; Kim, G.; Woo, H. J.; Kwon, J.; Lee, I. G.; Choi, E. M.; Chung, M.

    2017-12-01

    One of the main characteristics of the Goubau line is that it supports a low-loss, non-radiated surface wave guided by a dielectric-coated metal wire. The dominant mode of the surface wave along the Goubau line is a TM01 mode, which resembles the pattern of the electromagnetic fields induced in the metallic beam pipe when the charged particle beam passes through it. Therefore, the Goubau line can be used for the preliminary bench test and performance optimization of the beam diagnostic instruments without requiring charged particle beams from the accelerators. In this paper, we discuss the basic properties of the Goubau line for testing beam diagnostic instruments and present the initial test results for button-type beam position monitors (BPMs). The experimental results are consistent with the theoretical estimations, which indicates that Goubau line allows effective testing of beam diagnostic equipment.

  20. Improving students’ understanding of mathematical concept using maple

    NASA Astrophysics Data System (ADS)

    Ningsih, Y. L.; Paradesa, R.

    2018-01-01

    This study aimed to improve students’ understanding of mathematical concept ability through implementation of using Maple in learning and expository learning. This study used a quasi-experimental research with pretest-posttest control group design. The sample on this study was 61 students in the second semester of Mathematics Education of Universitas PGRI Palembang, South Sumatera in academic year 2016/2017. The sample was divided into two classes, one class as the experiment class who using Maple in learning and the other class as a control class who received expository learning. Data were collective through the test of mathematical initial ability and mathematical concept understanding ability. Data were analyzed by t-test and two ways ANOVA. The results of this study showed (1) the improvement of students’ mathematical concept understanding ability who using Maple in learning is better than those who using expository learning; (2) there is no interaction between learning model and students’ mathematical initial ability toward the improvement of students’ understanding of mathematical concept ability.

  1. The PNC-CAT insertion device beamline at the Advanced Photon Source

    NASA Astrophysics Data System (ADS)

    Heald, S. M.; Stern, E. A.; Brown, F. C.; Kim, K. H.; Barg, B.; Crozier, E. D.

    1996-09-01

    The PNC-CAT is a consortium of Pacific Northwest institutions formed to instrument a sector (number 20) at the Advanced Photon Source (APS). Research is planned in a variety of areas, with an emphasis on environmentally based problems. The insertion device beamline is based on the APS undulator A and will be optimized for producing microbeams as well as for applications requiring energy scanning capabilities. This paper describes the basic layout and some special features of the beamline. Two experimental stations are planned: one general purpose and one dedicated to MBE and surface science problems. Both tapered capillaries and Kirkpatrick-Baez optics will be used for producing microbeams, and a large optical bench is planned for the main station to allow for easy accommodation of new optics developments. Design calculations and initial capillary tests indicate that flux densities exceeding 1011 photons/sec/mm2 should be achievable. All major components are under construction or in procurement, and initial testing is planned for late 1996.

  2. Toxic epidermal necrolysis: Part II. Prognosis, sequelae, diagnosis, differential diagnosis, prevention, and treatment.

    PubMed

    Schwartz, Robert A; McDonough, Patrick H; Lee, Brian W

    2013-08-01

    Toxic epidermal necrolysis (TEN) is a life-threatening, typically drug-induced, mucocutaneous disease. TEN has a high mortality rate, making early diagnosis and treatment of paramount importance. New but experimental diagnostic tools that measure serum granulysin and high-mobility group protein B1 (HMGB1) offer the potential to differentiate early TEN from other, less serious drug reactions, but these tests have not been validated and are not readily available. The mainstay of treatment for TEN involves discontinuation of the offending drug, specialized care in an intensive care unit or burn center, and supportive therapy. Pharmacogenetic studies have clearly established a link between human leukocyte antigen allotype and TEN. Human leukocyte antigen testing should be performed on patients of East Asian descent before the initiation of carbamezapine and on all patients before the initiation of abacavir. The effectiveness of systemic steroids, intravenous immunoglobulins, plasmapheresis, cyclosporine, biologics, and other agents is uncertain. Copyright © 2013 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.

  3. Novel high-frequency, high-power, pulsed oscillator based on a transmission line transformer.

    PubMed

    Burdt, R; Curry, R D

    2007-07-01

    Recent analysis and experiments have demonstrated the potential for transmission line transformers to be employed as compact, high-frequency, high-power, pulsed oscillators with variable rise time, high output impedance, and high operating efficiency. A prototype system was fabricated and tested that generates a damped sinusoidal wave form at a center frequency of 4 MHz into a 200 Omega load, with operating efficiency above 90% and peak power on the order of 10 MW. The initial rise time of the pulse is variable and two experiments were conducted to demonstrate initial rise times of 12 and 3 ns, corresponding to a spectral content from 4-30 and from 4-100 MHz, respectively. A SPICE model has been developed to accurately predict the circuit behavior and scaling laws have been identified to allow for circuit design at higher frequencies and higher peak power. The applications, circuit analysis, test stand, experimental results, circuit modeling, and design of future systems are all discussed.

  4. On fractography of shallow and deep HY-100 cracked bend specimens

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

    Yuan, D.W.; Zarzour, J.F.; Kleinosky, M.J.

    1994-12-01

    The influence of shallow cracks on the fracture behavior of structural components has been studied extensively in recent years. Finite element analyses have indicated dramatic differences in the crack-tip stress states between shallow and deep cracked bend specimens. In this study, an experimental program was carried out to investigate the fracture behavior of HY-100 steel containing various initial flaw depths. Four a/w ratios ranging from 0.05 to 0.5 were chosen for the notched three-point bend tests. Test results showed that higher fracture toughness values are associated with specimens having shorter surface cracks. Also, fractographic studies indicated that two sets ofmore » dimples are present for a/w = 0.5 specimen, one set of equiaxed dimple for a/w = 0.05 specimen near the crack initiation zone. As the crack grows, increase in the volume fraction of the small dimple were observed. Finally, it showed that the characteristic features of the fracture surfaces can be correlated with the previous numerical predictions.« less

  5. Sputtered protective coatings for die casting dies

    NASA Technical Reports Server (NTRS)

    Mirtich, M. J.; Nieh, C.-Y.; Wallace, J. F.

    1981-01-01

    Three experimental research designs investigating candidate materials and processes involved in protective die surface coating procedures by sputter deposition, using ion beam technologies, are discussed. Various pre-test results show that none of the coatings remained completely intact for 15,000 test cycles. The longest lifetime was observed for coatings such as tungsten, platinum, and molybdenum which reduced thermal fatigue, but exhibited oxidation and suppressed crack initiation only as long as the coating did not fracture. Final test results confirmed earlier findings and coatings with Pt and W proved to be the candidate materials to be used on a die surface to increase die life. In the W-coated specimens, which remained intact on the surface after thermal fatigue testing, no oxidation was found under the coating, although a few cracks formed on the surface where the coating broke down. Further research is planned.

  6. Forming limit curves of DP600 determined in high-speed Nakajima tests and predicted by two different strain-rate-sensitive models

    NASA Astrophysics Data System (ADS)

    Weiß-Borkowski, Nathalie; Lian, Junhe; Camberg, Alan; Tröster, Thomas; Münstermann, Sebastian; Bleck, Wolfgang; Gese, Helmut; Richter, Helmut

    2018-05-01

    Determination of forming limit curves (FLC) to describe the multi-axial forming behaviour is possible via either experimental measurements or theoretical calculations. In case of theoretical determination, different models are available and some of them consider the influence of strain rate in the quasi-static and dynamic strain rate regime. Consideration of the strain rate effect is necessary as many material characteristics such as yield strength and failure strain are affected by loading speed. In addition, the start of instability and necking depends not only on the strain hardening coefficient but also on the strain rate sensitivity parameter. Therefore, the strain rate dependency of materials for both plasticity and the failure behaviour is taken into account in crash simulations for strain rates up to 1000 s-1 and FLC can be used for the description of the material's instability behaviour at multi-axial loading. In this context, due to the strain rate dependency of the material behaviour, an extrapolation of the quasi-static FLC to dynamic loading condition is not reliable. Therefore, experimental high-speed Nakajima tests or theoretical models shall be used to determine the FLC at high strain rates. In this study, two theoretical models for determination of FLC at high strain rates and results of experimental high-speed Nakajima tests for a DP600 are presented. One of the theoretical models is the numerical algorithm CRACH as part of the modular material and failure model MF GenYld+CrachFEM 4.2, which is based on an initial imperfection. Furthermore, the extended modified maximum force criterion considering the strain rate effect is also used to predict the FLC. These two models are calibrated by the quasi-static and dynamic uniaxial tensile tests and bulge tests. The predictions for the quasi-static and dynamic FLC by both models are presented and compared with the experimental results.

  7. Rapid screening test for gestational diabetes: public health need, market requirement, initial product design, and experimental results

    NASA Astrophysics Data System (ADS)

    Weigl, Bernhard H.; Zwisler, Greg; Peck, Roger; Abu-Haydar, Elizabeth

    2013-03-01

    Gestational diabetes is a global epidemic where many urban areas in Southeast Asia have found prevalence rates as high as 20%, exceeding the highest prevalence rates in the developed world. It can have serious and life-threatening consequences for mothers and babies. We are developing two variants of a new, simple, low-cost rapid test for screening for gestational diabetes mellitus for use primarily in low-resource settings. The pair of assays, both semiquantitative rapid diagnostic strip tests for glycated albumin, require neither fasting nor an oral glucose challenge test. One variant is an extremely simple strip test to estimate the level of total glycated albumin in blood. The other, which is slightly more complex and expensive, is a test that determines the ratio of glycated albumin to total albumin. The screening results can be used to refer women to receive additional care during delivery to avoid birth complications as well as counseling on diet and exercise during and after pregnancy. Results with the latter test may also be used to start treatment with glucose-lowering drugs. Both assays will be read visually. We present initial results of a preliminary cost-performance comparison model evaluating the proposed test versus existing alternatives. We also evaluated user needs and schematic paper microfluidics-based designs aimed at overcoming the challenge of visualizing relatively narrow differences between normal and elevated levels of glycated albumin in blood.

  8. Low tritium partial pressure permeation system for mass transport measurement in lead lithium eutectic

    DOE PAGES

    Pawelko, R. J.; Shimada, M.; Katayama, K.; ...

    2015-11-28

    This paper describes a new experimental system designed to investigate tritium mass transfer properties in materials important to fusion technology. Experimental activities were carried out at the Safety and Tritium Applied Research (STAR) facility located at the Idaho National Laboratory (INL). The tritium permeation measurement system was developed as part of the Japan/US TITAN collaboration to investigate tritium mass transfer properties in liquid lead lithium eutectic (LLE) alloy. The experimental system is configured to measure tritium mass transfer properties at low tritium partial pressures. Initial tritium permeation scoping tests were conducted on a 1 mm thick α-Fe plate to determinemore » operating parameters and to validate the experimental technique. A second series of permeation tests was then conducted with the α-Fe plate covered with an approximately 8.5 mm layer of liquid lead lithium eutectic alloy (α-Fe/LLE). We present preliminary tritium permeation data for α-Fe and α-Fe/LLE at temperatures between 400 and 600°C and at tritium partial pressures between 1.7E-3 and 2.5 Pa in helium. Preliminary results for the α-Fe plate and α-Fe/LLE indicate that the data spans a transition region between the diffusion-limited regime and the surface-limited regime. In conclusion, additional data is required to determine the existence and range of a surface-limited regime.« less

  9. How Do River Meanders Change with Sea Level Rise and Fall?

    NASA Astrophysics Data System (ADS)

    Scamardo, J. E.; Kim, W.

    2016-12-01

    River meander patterns are controlled by numerous factors, including variations in water discharge, sediment input, and base level. However, the effect of sea level rise and fall on meandering rivers has not been thoroughly quantified. This study examines geomorphic changes to meandering rivers as a result of sea level rise and fall. Twenty experimental runs using coarse-grained walnut shell sediment (D50= 500 microns) in a flume tank (2.4m x 0.6m x 0.1m) tested the optimal initial conditions for creating meandering rivers in a laboratory setting as well as variations in base level rise and fall rates. Geomorphic changes were recorded by camera images every 20 seconds for a duration of 4 hours per experiment. Seventeen experiments tested the effects of changes in initial base levels, water discharge between 200 and 400 mL/min, and sediment to water input ratios between 1:1000 and 1:250 while measuring sinuosity, channel geometry, and the timescale of the channel to reach a stable form. Sinuosity and channel activity increased with increasing water discharge, initial base level, and the sediment to water ratio to a point after which the activity decreased with increasing sediment input. Base-level change experiments used initial conditions of 400 mL/min, a 1:750 sediment to water input ratio, and a 6 cm initial base-level to induce river meanders for the initial 2 hours before base-level change occurred. Three separate experiments investigated the effects of increasing rates of sea level change: 0.07 cm/min, 0.1 cm/min, and 0.2 cm/min. Experimental sea level was decreased constantly from a high-stand of 6 cm to a low-stand of 2 cm back to the high-stand base-level in each experiment. The rates of change in the experiments scale roughly from central to glacial cycles. In all three experiments, sea level fall induced meander cut-off while sea level rise prompted greater rates of meander bend erosion and meander growth. Sinuosity increased by 12%, 13.5%, and 24%, respectively in the three experiments, with most sinuosity changes occurring in the downstream reach of the channel. These experiments could provide insight into long term effects of sea level change on modern meandering fluvial systems as well as provide a key to interpreting past fluvial changes in the stratigraphic record.

  10. Development of a beam builder for automatic fabrication of large composite space structures

    NASA Technical Reports Server (NTRS)

    Bodle, J. G.

    1979-01-01

    The composite material beam builder which will produce triangular beams from pre-consolidated graphite/glass/thermoplastic composite material through automated mechanical processes is presented, side member storage, feed and positioning, ultrasonic welding, and beam cutoff are formed. Each process lends itself to modular subsystem development. Initial development is concentrated on the key processes for roll forming and ultrasonic welding composite thermoplastic materials. The construction and test of an experimental roll forming machine and ultrasonic welding process control techniques are described.

  11. A flight investigation of simulated data-link communications during single-pilot IFR flight. Volume 1: Experimental design and initial test

    NASA Technical Reports Server (NTRS)

    Parker, J. F., Jr.; Duffy, J. W.; Christensen, D. G.

    1981-01-01

    A Flight Data Console simulation of a digital communication link to replace the current voice communication system used in air traffic control (ATC) was developed. The study determined how a digital communications system reduces cockpit workload, improve, flight proficiency, and is acceptable to general aviation pilots. It is shown that instrument flight, including approach and landing, can be accomplished by using a digital data link system for ATC communication.

  12. Modular biowaste monitoring system

    NASA Technical Reports Server (NTRS)

    Fogal, G. L.

    1975-01-01

    The objective of the Modular Biowaste Monitoring System Program was to generate and evaluate hardware for supporting shuttle life science experimental and diagnostic programs. An initial conceptual design effort established requirements and defined an overall modular system for the collection, measurement, sampling and storage of urine and feces biowastes. This conceptual design effort was followed by the design, fabrication and performance evaluation of a flight prototype model urine collection, volume measurement and sampling capability. No operational or performance deficiencies were uncovered as a result of the performance evaluation tests.

  13. Toxicity of the pyrolysis products of spacecraft materials

    NASA Technical Reports Server (NTRS)

    Lawrence, W. H.

    1976-01-01

    Data is presented which provides guides to (1) approximate temperature necessary to initiate thermodegradation of the polymeric materials tested, (2) the relative toxicity of thermodegradation products from the various materials, (3) the relative importance of carbon monoxide as the primary cause of death (as contrasted to cyanide or other toxic gases), and (4) whether or not the hazards of the fumes are confined to the time of exposure, or whether post-exposure death is likely. Two different experimental methods were employed.

  14. Analysis of Crystallization Kinetics

    NASA Technical Reports Server (NTRS)

    Kelton, Kenneth F.

    1997-01-01

    A realistic computer model for polymorphic crystallization (i.e., initial and final phases with identical compositions), which includes time-dependent nucleation and cluster-size-dependent growth rates, is developed and tested by fits to experimental data. Model calculations are used to assess the validity of two of the more common approaches for the analysis of crystallization data. The effects of particle size on transformation kinetics, important for the crystallization of many systems of limited dimension including thin films, fine powders, and nanoparticles, are examined.

  15. A method for the modelling of porous and solid wind tunnel walls in computational fluid dynamics codes

    NASA Technical Reports Server (NTRS)

    Beutner, Thomas John

    1993-01-01

    Porous wall wind tunnels have been used for several decades and have proven effective in reducing wall interference effects in both low speed and transonic testing. They allow for testing through Mach 1, reduce blockage effects and reduce shock wave reflections in the test section. Their usefulness in developing computational fluid dynamics (CFD) codes has been limited, however, by the difficulties associated with modelling the effect of a porous wall in CFD codes. Previous approaches to modelling porous wall effects have depended either upon a simplified linear boundary condition, which has proven inadequate, or upon detailed measurements of the normal velocity near the wall, which require extensive wind tunnel time. The current work was initiated in an effort to find a simple, accurate method of modelling a porous wall boundary condition in CFD codes. The development of such a method would allow data from porous wall wind tunnels to be used more readily in validating CFD codes. This would be beneficial when transonic validations are desired, or when large models are used to achieve high Reynolds numbers in testing. A computational and experimental study was undertaken to investigate a new method of modelling solid and porous wall boundary conditions in CFD codes. The method utilized experimental measurements at the walls to develop a flow field solution based on the method of singularities. This flow field solution was then imposed as a pressure boundary condition in a CFD simulation of the internal flow field. The effectiveness of this method in describing the effect of porosity changes on the wall was investigated. Also, the effectiveness of this method when only sparse experimental measurements were available has been investigated. The current work demonstrated this approach for low speed flows and compared the results with experimental data obtained from a heavily instrumented variable porosity test section. The approach developed was simple, computationally inexpensive, and did not require extensive or intrusive measurements of the boundary conditions during the wind tunnel test. It may be applied to both solid and porous wall wind tunnel tests.

  16. Experimental and finite element analysis of tibial stress fractures using a rabbit model.

    PubMed

    Franklyn, Melanie; Field, Bruce

    2013-01-01

    To determine if rabbit models can be used to quantify the mechanical behaviour involved in tibial stress fracture (TSF) development. Fresh rabbit tibiae were loaded under compression using a specifically-designed test apparatus. Weights were incrementally added up to a load of 30 kg and the mechanical behaviour of the tibia was analysed using tests for buckling, bone strain and hysteresis. Structural mechanics equations were subsequently employed to verify that the results were within the range of values predicted by theory. A finite element (FE) model was developed using cross-sectional computer tomography (CT) images scanned from one of the rabbit bones, and a static load of 6 kg (1.5 times the rabbit's body weight) was applied to represent running. The model was validated using the experimental strain gauge data, then geometric and elemental convergence tests were performed in order to find the minimum number of cross-sectional scans and elements respectively required for convergence. The analysis was then performed using both the model and the experimental results to investigate the mechanical behaviour of the rabbit tibia under compressive load and to examine crack initiation. The experimental tests showed that under a compressive load of up to 12 kg, the rabbit tibia demonstrates linear behaviour with little hysteresis. Up to 30 kg, the bone does not fail by elastic buckling; however, there are low levels of tensile stress which predominately occur at and adjacent to the anterior border of the tibial midshaft: this suggests that fatigue failure occurs in these regions, since bone under cyclic loading initially fails in tension. The FE model predictions were consistent with both mechanics theory and the strain gauge results. The model was highly sensitive to small changes in the position of the applied load due to the high slenderness ratio of the rabbit's tibia. The modelling technique used in the current study could have applications in the development of human FE models of bone, where, unlike rabbit tibia, the model would be relatively insensitive to very small changes in load position. However, the rabbit model itself is less beneficial as a tool to understand the mechanical behaviour of TSFs in humans due to the small size of the rabbit bone and the limitations of human-scale CT scanning equipment. The current modelling technique could be used to develop human FE models. However, the rabbit model itself has significant limitations in understanding human TSF mechanics.

  17. Comparison of ISRU Excavation System Model Blade Force Methodology and Experimental Results

    NASA Technical Reports Server (NTRS)

    Gallo, Christopher A.; Wilkinson, R. Allen; Mueller, Robert P.; Schuler, Jason M.; Nick, Andrew J.

    2010-01-01

    An Excavation System Model has been written to simulate the collection and transportation of regolith on the Moon. The calculations in this model include an estimation of the forces on the digging tool as a result of excavation into the regolith. Verification testing has been performed and the forces recorded from this testing were compared to the calculated theoretical data. A prototype lunar vehicle built at the NASA Johnson Space Center (JSC) was tested with a bulldozer type blade developed at the NASA Kennedy Space Center (KSC) attached to the front. This is the initial correlation of actual field test data to the blade forces calculated by the Excavation System Model and the test data followed similar trends with the predicted values. This testing occurred in soils developed at the NASA Glenn Research Center (GRC) which are a mixture of different types of sands and whose soil properties have been well characterized. Three separate analytical models are compared to the test data.

  18. Development of a high-efficiency motor/generator for flywheel energy storage

    NASA Astrophysics Data System (ADS)

    Lashley, Christopher; Anand, Dave K.; Kirk, James A.; Zmood, Ronald B.

    This study addresses the design changes and extensions necessary to construct and test a working prototype of a motor/generator for a magnetically suspended flywheel energy storage system. The brushless motor controller for the motor was specified and the electronic commutation arrangement designed. The laminations were redesigned and fabricated using laser machining. Flux density measurements were made and the results used to redesign the armature windings. A test rig was designed and built, and the motor/generator was installed and speed tested to 9000 rpm. Experimental methods of obtaining the machine voltage and torque constants Kv and Kt, obtaining the useful air-gap flux density, and characterizing the motor and other system components are described. The measured Kv and Kt were approximately 40 percent greater than predicted by theory and initial experiment.

  19. Development of a high-efficiency motor/generator for flywheel energy storage

    NASA Technical Reports Server (NTRS)

    Lashley, Christopher; Anand, Dave K.; Kirk, James A.; Zmood, Ronald B.

    1991-01-01

    This study addresses the design changes and extensions necessary to construct and test a working prototype of a motor/generator for a magnetically suspended flywheel energy storage system. The brushless motor controller for the motor was specified and the electronic commutation arrangement designed. The laminations were redesigned and fabricated using laser machining. Flux density measurements were made and the results used to redesign the armature windings. A test rig was designed and built, and the motor/generator was installed and speed tested to 9000 rpm. Experimental methods of obtaining the machine voltage and torque constants Kv and Kt, obtaining the useful air-gap flux density, and characterizing the motor and other system components are described. The measured Kv and Kt were approximately 40 percent greater than predicted by theory and initial experiment.

  20. Highly loaded multi-stage fan drive turbine - performance of initial seven configurations

    NASA Technical Reports Server (NTRS)

    Wolfmeyer, G. W.; Thomas, M. W.

    1974-01-01

    Experimental results of a three-stage highly loaded fan drive turbine test program are presented. A plain blade turbine, a tandem blade turbine, and a tangentially leaned stator turbine were designed for the same velocity diagram and flowpath. Seven combinations of bladerows were tested to evaluate stage performances and effects of the tandem blading and leaned stator. The plain blade turbine design point total-to-total efficiency was 0.886. The turbine with the stage three leaned stator had the same efficiency with an improved exit swirl profile and increased hub reaction. Two-stage group tests showed that the two-stage turbine with tandem stage two stator had an efficiency of 0.880 compared to 0.868 for the plain blade two-stage turbine.

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