Science.gov

Sample records for actual experimental materials

  1. On Experimental Thermal Analysis of Solid Materials

    NASA Astrophysics Data System (ADS)

    Koštial, Pavel; Špička, Ivo; Jančikova, Zora; Valiček, Jan; Harničarova, Marta; Hlinka, Josef

    2014-12-01

    The paper is devoted to the presentation of a method for measurement of thermal conductivity k, specific heat capacity cp, and thermal diffusivity applying the lumped capacitance model (LCM) as a special case of Newton's model of cooling. At the specific experimental conditions resulting from the theoretical analysis of the used model, we present a method for experimental determination of all three above mentioned thermal parameters for materials with different thermal transport properties. The input experimental data provide a cooling curve of the tested material. The evaluation of experimental data is realized by software, the fundamental features of which are presented here. The statistical analysis of experimental data was performed.

  2. Experimental study using infrared thermography on the convective heat transfer of a TGV brake disc in the actual environment

    NASA Astrophysics Data System (ADS)

    Siroux, Monica; Harmand, Souad; Desmet, Bernard

    2002-07-01

    We present an experimental identification of the local and mean Nusselt number from a rotating TGV brake disk model in the actual environment and exposed to an air flow parallel to the disk surface. This method is based on the use of a heated thermally thick disk combined with the technique of temperature measurement by infrared thermography. The local and mean convective heat transfer coefficient from the disk surface is identified by solving the steady state heat equation by a finite difference method using the experimental temperature distribution as boundary conditions. The experimental setup is constituted of a model disk with all the representative parts of the actual TGV brake system. The disk and its actual environment are inside a wind tunnel test section, so that the rotational disk speed and the air flow velocity can be varied. Tests were carried out for rotational speeds w between 325 and 2000 rpm (rotational Reynolds number Re between 88,500 and 545,000), and for an air flow velocity U ranging between 0 and 12 m(DOT)s-1 (air flow Reynolds number Re0 between 0 and 153,000).

  3. Experimental study using infrared thermography on the convective heat transfer of a TGV brake disc in the actual environment

    NASA Astrophysics Data System (ADS)

    Siroux, Monica; Harmand, Souad; Desmet, Bernard

    2001-03-01

    Local and mean convective heat transfer from a rotating TGV brake disc model in the actual environment and submitted to an air flow parallel to the disc surface is studied experimentally in this paper. The experimental technique is based on the use of a heated thermally thick disc combined with the technique of temperature measurement by infrared thermography. The local convective heat transfer coefficient from the disc surface is identified by solving the steady state heat equation by finite difference method using the experimental temperature distribution as boundary conditions. These tests were carried out for rotational speed (omega) between 325 and 2000 rpm (rotational Reynolds number Re between 88500 and 545000) so as to obtain laminar and turbulent flow on the disc, and for air flow velocity U ranging between 0 and 12 m s-1 (air flow Reynolds number Re0 between 0 and 153000).

  4. Experimental evaluation of actual delivered dose using mega-voltage cone-beam CT and direct point dose measurement

    SciTech Connect

    Matsubara, Kana; Kohno, Ryosuke; Nishioka, Shie; Shibuya, Toshiyuki; Ariji, Takaki; Akimoto, Tetsuo; Saitoh, Hidetoshi

    2013-07-01

    Radiation therapy in patients is planned by using computed tomography (CT) images acquired before start of the treatment course. Here, tumor shrinkage or weight loss or both, which are common during the treatment course for patients with head-and-neck (H and N) cancer, causes unexpected differences from the plan, as well as dose uncertainty with the daily positional error of patients. For accurate clinical evaluation, it is essential to identify these anatomical changes and daily positional errors, as well as consequent dosimetric changes. To evaluate the actual delivered dose, the authors proposed direct dose measurement and dose calculation with mega-voltage cone-beam CT (MVCBCT). The purpose of the present study was to experimentally evaluate dose calculation by MVCBCT. Furthermore, actual delivered dose was evaluated directly with accurate phantom setup. Because MVCBCT has CT-number variation, even when the analyzed object has a uniform density, a specific and simple CT-number correction method was developed and applied for the H and N site of a RANDO phantom. Dose distributions were calculated with the corrected MVCBCT images of a cylindrical polymethyl methacrylate phantom. Treatment processes from planning to beam delivery were performed for the H and N site of the RANDO phantom. The image-guided radiation therapy procedure was utilized for the phantom setup to improve measurement reliability. The calculated dose in the RANDO phantom was compared to the measured dose obtained by metal-oxide-semiconductor field-effect transistor detectors. In the polymethyl methacrylate phantom, the calculated and measured doses agreed within about +3%. In the RANDO phantom, the dose difference was less than +5%. The calculated dose based on simulation-CT agreed with the measured dose within±3%, even in the region with a high dose gradient. The actual delivered dose was successfully determined by dose calculation with MVCBCT, and the point dose measurement with the image

  5. Experimental Fracture Measurements of Functionally Graded Materials

    NASA Astrophysics Data System (ADS)

    Carpenter, Ray Douglas

    The primary objective of this research was to extend established fracture toughness testing methods to a new class of engineering materials known as functionally graded materials (FGMs). Secondary goals were to compare experimental results to those predicted by finite element models and to provide fracture test results as feedback toward optimizing processing parameters for the in-house synthesis of a MoSi2/SiC FGM. Preliminary experiments were performed on commercially pure (CP) Ti and uniform axial tensile tests resulted in mechanical property data including yield strength, 268 MPa, ultimate tensile strength, 470 MPa and Young's modulus, 110 GPa. Results from 3-point bending fracture experiments on CP Ti demonstrated rising R-curve behavior and experimentally determined JQ fracture toughness values ranged between 153 N/mm and 254 N/mm. Similar experimental protocols were used for fracture experiments on a 7- layered Ti/TiB FGM material obtained from Cercom in Vista, California. A novel technique for pre-cracking in reverse 4-point bending was developed for this ductile/brittle FGM material. Fracture test results exhibited rising R-curve behavior and estimated JQ fracture toughness values ranged from 0.49 N/mm to 2.63 N/mm. A 5- layered MoSi2/SiC FGM was synthesized using spark plasma sintering (SPS). Samples of this material were fracture tested and the results again exhibited a rising R-curve with KIC fracture toughness values ranging from 2.7 MPa-m1/2 to 6.0 MPa-m1/2. Finite Element Models predicted rising R-curve behavior for both of the FGM materials tested. Model results were in close agreement for the brittle MoSi2/SiC FGM. For the relatively more ductile Ti/TiB material, results were in close agreement at short crack lengths but diverged at longer crack lengths because the models accounted for fracture toughening mechanisms at the crack tip but not those acting in the crack wake.

  6. Numerical reconstruction of part of an actual blast-wave flow field to agree with available experimental data

    NASA Astrophysics Data System (ADS)

    Lau, S. C. M.; Gottlieb, J. J.

    1983-11-01

    A method of solution is presented and validated for the numerical reconstruction of a certain part of an actual blast-wave flow field of interest for planar, cylindrical and spherical explosions, away from the explosion source where the blast-wave has become sufficiently weak that real-gas effects are unimportant. This method involves, essentially, a trial-and-error process of constructing the best possible path of a fluid particle or equivalent piston at the upstream side of the flow field of interest such that the resulting flow field constructed numerically in front of the equivalent moving piston agrees as well as possible with all available although limited experimental data. The relatively new random-choice method was suitably modified to easily handle the numerical computations of the nonstationary flow in front of the moving piston. Finally, the present method is used to reconstruct the flow field for past TNT and ANFO explosions, for which the blast-wave amplitudes are less than about 1 MPa. These results are presented in convenient graphical and tabular form, scaled for the case of a 1-kg TNT surface explosion or its equivalent in a standard atmosphere, so that they can be utilized readily for different sized explosions at the same or other atmospheric conditions.

  7. Experimental Verification of Material Flammability in Space

    NASA Technical Reports Server (NTRS)

    Ivanov, A. V.; Balashov, Y. V.; Andreeva, T. V.; Melikhov, A. S.

    1999-01-01

    The flammability in microgravity of three US-furnished materials, Delrin, polymethylmethacrylate (PMMA), and high-density polyethylene, was determined using a Russian-developed combustion tunnel on Mir. Four 4.5-mm-diameter cylindrical samples of each plastic were ignited under concurrent airflow (in the direction of flame spread) with velocities from no flow to 8.5 cm/s. The test results identify a limiting air-flow velocity V(sub lim) for each material, below which combustion ceases. Nominal values are V(sub lim) < 0.3 cm/s for Delrin, 0.5 cm/s for PMMA, and 0.3 to 0.5 cm/s for polyethylene. These values are lower than those obtained in prior ground testing. Nevertheless, they demonstrate that flow shutoff is effective for extinguishment in the microgravity environment of spacecraft. Microgravity test results also show that the plastic materials maintain a stable melt ball within the spreading flame zone. In general, as the concurrent flow velocity V decreases, the flame-spread rate V(sub F) decreases, from an average (for all three materials) of V(sub F)= 0.5-0.75 mm/s at V = 8.5 cm/s to V(sub F)= 0.05-0.01 mm/s at V = 0.3-0.5 cm/s. Also, as V decreases, the flames become less visible but expand, increasing the probability of igniting an adjacent surface.

  8. Double-blind photo lineups using actual eyewitnesses: an experimental test of a sequential versus simultaneous lineup procedure.

    PubMed

    Wells, Gary L; Steblay, Nancy K; Dysart, Jennifer E

    2015-02-01

    Eyewitnesses (494) to actual crimes in 4 police jurisdictions were randomly assigned to view simultaneous or sequential photo lineups using laptop computers and double-blind administration. The sequential procedure used in the field experiment mimicked how it is conducted in actual practice (e.g., using a continuation rule, witness does not know how many photos are to be viewed, witnesses resolve any multiple identifications), which is not how most lab experiments have tested the sequential lineup. No significant differences emerged in rates of identifying lineup suspects (25% overall) but the sequential procedure produced a significantly lower rate (11%) of identifying known-innocent lineup fillers than did the simultaneous procedure (18%). The simultaneous/sequential pattern did not significantly interact with estimator variables and no lineup-position effects were observed for either the simultaneous or sequential procedures. Rates of nonidentification were not significantly different for simultaneous and sequential but nonidentifiers from the sequential procedure were more likely to use the "not sure" response option than were nonidentifiers from the simultaneous procedure. Among witnesses who made an identification, 36% (41% of simultaneous and 32% of sequential) identified a known-innocent filler rather than a suspect, indicating that eyewitness performance overall was very poor. The results suggest that the sequential procedure that is used in the field reduces the identification of known-innocent fillers, but the differences are relatively small. PMID:24933175

  9. Exposure to alcohol commercials in movie theaters affects actual alcohol consumption in young adult high weekly drinkers: an experimental study.

    PubMed

    Koordeman, Renske; Anschutz, Doeschka J; Engels, Rutger C M E

    2011-01-01

    The present pilot study examined the effects of alcohol commercials shown in movie theaters on the alcohol consumption of young adults who see these commercials. A two (alcohol commercials vs. nonalcohol commercials) by two (high weekly alcohol consumption vs. low weekly alcohol consumption) between-participant design was used, in which 184 young adults (age: 16-28 years) were exposed to a movie that was preceded by either alcohol commercials or nonalcohol commercials. Participants' actual alcohol consumption while watching the movie ("Watchmen") was examined. An analysis of variance (ANOVA) was conducted to examine the effects of the commercial condition on alcohol consumption. An interaction effect was found between commercial condition and weekly alcohol consumption (p < .001). Alcohol consumption among high weekly alcohol drinkers was higher in the alcohol commercial condition than in the nonalcohol commercial condition, whereas no differences were found in alcohol consumption between commercial conditions among low weekly alcohol drinkers. No gender differences were found in the association between exposure to alcohol commercials, weekly drinking, and alcohol use. Thus, exposure to alcohol commercials prior to a movie in a movie theater can directly influence alcohol consumption among high weekly alcohol consumers. PMID:21477057

  10. Exposure to alcohol commercials in movie theaters affects actual alcohol consumption in young adult high weekly drinkers: an experimental study.

    PubMed

    Koordeman, Renske; Anschutz, Doeschka J; Engels, Rutger C M E

    2011-01-01

    The present pilot study examined the effects of alcohol commercials shown in movie theaters on the alcohol consumption of young adults who see these commercials. A two (alcohol commercials vs. nonalcohol commercials) by two (high weekly alcohol consumption vs. low weekly alcohol consumption) between-participant design was used, in which 184 young adults (age: 16-28 years) were exposed to a movie that was preceded by either alcohol commercials or nonalcohol commercials. Participants' actual alcohol consumption while watching the movie ("Watchmen") was examined. An analysis of variance (ANOVA) was conducted to examine the effects of the commercial condition on alcohol consumption. An interaction effect was found between commercial condition and weekly alcohol consumption (p < .001). Alcohol consumption among high weekly alcohol drinkers was higher in the alcohol commercial condition than in the nonalcohol commercial condition, whereas no differences were found in alcohol consumption between commercial conditions among low weekly alcohol drinkers. No gender differences were found in the association between exposure to alcohol commercials, weekly drinking, and alcohol use. Thus, exposure to alcohol commercials prior to a movie in a movie theater can directly influence alcohol consumption among high weekly alcohol consumers.

  11. Actual principles of the simulation of state-of-the-art technologies of laser processing of materials

    NASA Astrophysics Data System (ADS)

    Kovalev, Oleg B.

    2011-02-01

    Here we present the results of mathematical, numerical, and experimental simulation of the processes of interaction between the laser radiation and metals in the technologies of gas-laser cutting of thick-sheet materials and laser gas-powder cladding at the production of coatings and 3D objects by the DMD (Direct Material Deposition) method. The peculiarities of jet 3D flows of the working gases in narrow channels, geometrically identical to keyholes, are studied. It is demonstrated that during the stainless steel cutting, supersonic gas flows form local regions of separation flows which in turn result in the worse carry-away of the metal by the gas flow; these factors increase the roughness (striation) and worsen the surface quality. A vortex flow was found inside the cut at the subsonic jet flows typical for the oxygen gas-laser cutting of low-carbon steel; this flow causes slagging of the cut bottom edge. The processes running inside the laser cut at the fusible metals cutting with the low-power radiation were visualized under the laboratory conditions. Some new concepts of the processes running inside the keyhole have been gained; we also propose the explanations of the mechanisms of striation and other surface defects formation during the cutting of thick-sheet standard metals on the automate laser technological complex. A mathematical model of the volumetric laser-powder cladding is proposed. The submitted results concern the numerical simulation of multi-layer flows of shaping and carrier gases with the gas-jet transportation of powder particles into the laser spot on the substrate.

  12. Actual principles of the simulation of state-of-the-art technologies of laser processing of materials

    NASA Astrophysics Data System (ADS)

    Kovalev, Oleg B.

    2010-07-01

    Here we present the results of mathematical, numerical, and experimental simulation of the processes of interaction between the laser radiation and metals in the technologies of gas-laser cutting of thick-sheet materials and laser gas-powder cladding at the production of coatings and 3D objects by the DMD (Direct Material Deposition) method. The peculiarities of jet 3D flows of the working gases in narrow channels, geometrically identical to keyholes, are studied. It is demonstrated that during the stainless steel cutting, supersonic gas flows form local regions of separation flows which in turn result in the worse carry-away of the metal by the gas flow; these factors increase the roughness (striation) and worsen the surface quality. A vortex flow was found inside the cut at the subsonic jet flows typical for the oxygen gas-laser cutting of low-carbon steel; this flow causes slagging of the cut bottom edge. The processes running inside the laser cut at the fusible metals cutting with the low-power radiation were visualized under the laboratory conditions. Some new concepts of the processes running inside the keyhole have been gained; we also propose the explanations of the mechanisms of striation and other surface defects formation during the cutting of thick-sheet standard metals on the automate laser technological complex. A mathematical model of the volumetric laser-powder cladding is proposed. The submitted results concern the numerical simulation of multi-layer flows of shaping and carrier gases with the gas-jet transportation of powder particles into the laser spot on the substrate.

  13. Theoretical Prediction and Experimental Realization of Missing Materials

    SciTech Connect

    Zakutayev, A.; Zhang, X.; Nagaraja, A.; Yu, L.; Lany, S.; Mason, T. O.; Ginley, D. S.; Zunger, A.

    2013-01-01

    Many chemically reasonable inorganic materials are missing from databases or literature. Two possible reasons are: (1) these materials are unstable; (2) they have been simply overlooked. Here we applied Inverse Design approach to systematically screen V-IX-IV group of 45 ternary ABX materials. High-throughput theory revealed 9 hitherto missing stable materials in this family. Combinatorial experiment synthesized one of them TaCoSn and discovered another one TaCo2Sn, the first two reported ternaries in this chemical system. This example illustrates the promise of computationally driven experimental inorganic materials chemistry.

  14. Finite element simulation of flexible roll forming with supplemented material data and the experimental verification

    NASA Astrophysics Data System (ADS)

    Yan, Yu; Wang, Haibo; Li, Qiang; Guan, Yanzhi

    2016-03-01

    Flexible roll forming is a promising manufacturing method for the production of variable cross section products. Considering the large plastic strain in this forming process which is much larger than that of uniform deformation phase of uniaxial tensile test, the widely adopted method of simulating the forming processes with non-supplemented material data from uniaxial tensile test will certainly lead to large error. To reduce this error, the material data is supplemented based on three constitutive models. Then a finite element model of a six passes flexible roll forming process is established based on the supplemented material data and the original material data from the uniaxial tensile test. The flexible roll forming experiment of a B pillar reinforcing plate is carried out to verify the proposed method. Final cross section shapes of the experimental and the simulated results are compared. It is shown that the simulation calculated with supplemented material data based on Swift model agrees well with the experimental results, while the simulation based on original material data could not predict the actual deformation accurately. The results indicate that this material supplement method is reliable and indispensible, and the simulation model can well reflect the real metal forming process. Detailed analysis of the distribution and history of plastic strain at different positions are performed. A new material data supplement method is proposed to tackle the problem which is ignored in other roll forming simulations, and thus the forming process simulation accuracy can be greatly improved.

  15. Experimental determination of material constants of a hybrid composite laminate

    SciTech Connect

    Ihekweazu, S.N.; Lari, S.B.; Unanwa, C.O.

    1999-07-01

    This paper discusses the results of the experimental study that was conducted in order to determine the material properties of a hybrid composite laminate made from Fiberite material MXM-7714/120 (a fabric prepreg consisting of woven Kevlar{reg_sign} 49 reinforcement impregnated with Fiberite 250 F (121 C) curing 7714 epoxy resin) and HYE-2448AIE (a 250 F (121 C) curing epoxy resin impregnated unidirectional graphite tape). First, each of the materials that comprise the hybrid laminate was fabricated separately according to ASTM-D-3039 specification in order to determine their material properties. The materials were then hybridized and the properties were determined. Data from this experiment reveal that a new class of material that can meet desired specifications can be created through hybridization. The data also revealed that the properties of the materials bonded together as a hybrid complement the properties of the constituent members of the hybrid.

  16. Nonlinear behavior of coupled magnetostrictive material systems analytical/experimental

    NASA Astrophysics Data System (ADS)

    Roberts, Mark M.; Mitrovic, Milan; Carman, Gregory P.

    1995-05-01

    In this paper, we present a nonlinear constitutive relation for magnetostrictive materials that includes coupling between temperature/preload and magnetic field strengths. The nonlinear constitutive relations are also integrated into a 1-dimensional nonlinear finite element model for studying structural components or composite materials containing magnetostrictive materials. The accuracy of the nonlinear constitutive relation is evaluated by comparing experimental results obtained on a Terfenol-D rod operating under both magnetic field and stress biases with theoretical values present in the literature. Results indicate that the model adequately predicts the nonlinear strain/field relations in specific regimes. Experimental tests, conducted on monolithic samples of different geometry, suggests that size effects may be important. A manufacturing process and preliminary experimental tests are also presented for a 1 - 3 magnetostrictive composite sample.

  17. Experimental device for measuring the momentum of disperse granular materials

    SciTech Connect

    Watling, H.E.; Griffiths, S.K.

    1982-02-10

    An experimental device for measuring the time averaged momentum associated with a steady stream of a disperse granular material has been developed. The mathematical basis for the device is presented including a discussion of using the momentum measurement to compute the local mass or energy fluxes. The analysis considers both nonuniform particle mass and nonuniform velocities for the various constituents of an aggregate material. The results of calibration experiments conducted with a prototype transducer are shown with theoretical predictions of these results.

  18. Experimental comparison of empirical material decomposition methods for spectral CT.

    PubMed

    Zimmerman, Kevin C; Schmidt, Taly Gilat

    2015-04-21

    Material composition can be estimated from spectral information acquired using photon counting x-ray detectors with pulse height analysis. Non-ideal effects in photon counting x-ray detectors such as charge-sharing, k-escape, and pulse-pileup distort the detected spectrum, which can cause material decomposition errors. This work compared the performance of two empirical decomposition methods: a neural network estimator and a linearized maximum likelihood estimator with correction (A-table method). The two investigated methods differ in how they model the nonlinear relationship between the spectral measurements and material decomposition estimates. The bias and standard deviation of material decomposition estimates were compared for the two methods, using both simulations and experiments with a photon-counting x-ray detector. Both the neural network and A-table methods demonstrated a similar performance for the simulated data. The neural network had lower standard deviation for nearly all thicknesses of the test materials in the collimated (low scatter) and uncollimated (higher scatter) experimental data. In the experimental study of Teflon thicknesses, non-ideal detector effects demonstrated a potential bias of 11-28%, which was reduced to 0.1-11% using the proposed empirical methods. Overall, the results demonstrated preliminary experimental feasibility of empirical material decomposition for spectral CT using photon-counting detectors.

  19. Experimental comparison of empirical material decomposition methods for spectral CT

    NASA Astrophysics Data System (ADS)

    Zimmerman, Kevin C.; Gilat Schmidt, Taly

    2015-04-01

    Material composition can be estimated from spectral information acquired using photon counting x-ray detectors with pulse height analysis. Non-ideal effects in photon counting x-ray detectors such as charge-sharing, k-escape, and pulse-pileup distort the detected spectrum, which can cause material decomposition errors. This work compared the performance of two empirical decomposition methods: a neural network estimator and a linearized maximum likelihood estimator with correction (A-table method). The two investigated methods differ in how they model the nonlinear relationship between the spectral measurements and material decomposition estimates. The bias and standard deviation of material decomposition estimates were compared for the two methods, using both simulations and experiments with a photon-counting x-ray detector. Both the neural network and A-table methods demonstrated a similar performance for the simulated data. The neural network had lower standard deviation for nearly all thicknesses of the test materials in the collimated (low scatter) and uncollimated (higher scatter) experimental data. In the experimental study of Teflon thicknesses, non-ideal detector effects demonstrated a potential bias of 11-28%, which was reduced to 0.1-11% using the proposed empirical methods. Overall, the results demonstrated preliminary experimental feasibility of empirical material decomposition for spectral CT using photon-counting detectors.

  20. Experimental Comparison of Empirical Material Decomposition Methods for Spectral CT

    PubMed Central

    Zimmerman, Kevin C.; Schmidt, Taly Gilat

    2015-01-01

    Material composition can be estimated from spectral information acquired using photon counting x-ray detectors with pulse height analysis. Non-ideal effects in photon counting x-ray detectors such as charge-sharing, k-escape, and pulse-pileup distort the detected spectrum, which can cause material decomposition errors. This work compared the performance of two empirical decomposition methods: a neural network estimator and a linearized maximum likelihood estimator with correction (A-table method). The two investigated methods differ in how they model the nonlinear relationship between the spectral measurements and material decomposition estimates. The bias and standard deviation of material decomposition estimates were compared for the two methods, using both simulations and experiments with a photon-counting x-ray detector. Both the neural network and A-table methods demonstrated similar performance for the simulated data. The neural network had lower standard deviation for nearly all thicknesses of the test materials in the collimated (low scatter) and uncollimated (higher scatter) experimental data. In the experimental study of Teflon thicknesses, non-ideal detector effects demonstrated a potential bias of 11–28%, which was reduced to 0.1–11% using the proposed empirical methods. Overall, the results demonstrated preliminary experimental feasibility of empirical material decomposition for spectral CT using photon-counting detectors. PMID:25813054

  1. Performance evaluation of 24 ion exchange materials for removing cesium and strontium from actual and simulated N-Reactor storage basin water

    SciTech Connect

    Brown, G.N.; Carson, K.J.; DesChane, J.R.; Elovich, R.J.

    1997-09-01

    This report describes the evaluation of 24 organic and inorganic ion exchange materials for removing cesium and strontium from actual and simulated waters from the 100 Area 105 N-Reactor fuel storage basin. The data described in this report can be applied for developing and evaluating ion exchange pre-treatment process flowsheets. Cesium and strontium batch distribution ratios (K{sub d}`s), decontamination factors (DF), and material loadings (mmol g{sup -1}) are compared as a function of ion exchange material and initial cesium concentration. The actual and simulated N-Basin waters contain relatively low levels of aluminum, barium, calcium, potassium, and magnesium (ranging from 8.33E-04 to 6.40E-05 M), with slightly higher levels of boron (6.63E-03 M) and sodium (1.62E-03 M). The {sup 137}Cs level is 1.74E-06 Ci L-{sup 1} which corresponds to approximately 4.87E-10 M Cs. The initial Na/Cs ratio was 3.33E+06. The concentration of total strontium is 4.45E-06 M, while the {sup 90}Sr radioactive component was measured to be 6.13E-06 Ci L{sup -1}. Simulant tests were conducted by contacting 0.067 g or each ion exchange material with approximately 100 mL of either the actual or simulated N-Basin water. The simulants contained variable initial cesium concentrations ranging from 1.00E-04 to 2.57E- 10 M Cs while all other components were held constant. For all materials, the average cesium K{sub d} was independent of cesium concentration below approximately 1.0E-06 M. Above this level, the average cesium K{sub d} values decreased significantly. Cesium K{sub d} values exceeding 1.0E+07 mL g{sup -1} were measured in the simulated N-Basin water. However, when measured in the actual N-Basin water the values were several orders of magnitude lower, with a maximum of 1.24E+05 mL g{sup -1} observed.

  2. Experimental Studies of Mitigation Materials for Blast Induced Tbi

    NASA Astrophysics Data System (ADS)

    Alley, M. D.; Son, S. F.; Christou, G.; Goel, R.; Young, L.

    2009-12-01

    The objective of this experimental study is to compare the effects of various materials obstructing the flow of a blast wave and the ability of the material to reduce the damage caused by the blast. Several methods of energy transfer in blast wave flows are expected including: material interfaces with impedance mismatches, density changes in a given material, internal shearing, and particle fracture. Our hypothesis is that the greatest energy transfer within the obstructing material will yield the greatest mitigation effects to the blast. Sample configurations of foam were varied to introduce material interfaces and filler materials with varying densities and impedances (liquids and powders). The samples were dynamically loaded using a small scale blast produced by an explosive driven shock tube housing gram-scale explosive charges. The transmitted blast profiles were analyzed for variations in impulse characteristics and frequency components as compared to standard free field profiles. The results showed a rounding effect of the transmitted blast profile for all samples with the effects of the high density fillers surpassing all others tested. These results lead to a conclusion that low porosity, high density materials offer superior attenuation by reducing air blast features and spatially distributing the transmitted wave.

  3. Experimental Studies of Mitigation Materials for Blast Induced TBI

    NASA Astrophysics Data System (ADS)

    Alley, Matthew; Son, Steven

    2009-06-01

    The objective of this experimental study is to compare the effects of various materials obstructing the flow of a blast wave and the ability of the given material to reduce the damage caused by the blast. Several methods of energy transfer in blast wave flows are known or expected including: material interfaces with impedance mismatches, density changes in a given material, internal shearing, and particle fracture. The theory applied to this research is that the greatest energy transfer within the obstructing material will yield the greatest mitigation effects to the blast. Sample configurations of foam were varied to introduce material interfaces and filler materials with varying densities and impedances (liquids and powders). The samples were loaded according to a small scale blast produced by an explosive driven shock tube housing gram-range charges. The transmitted blast profiles were analyzed for variations in impulse characteristics and frequency components as compared to standard free field profiles. The results showed a rounding effect of the transmitted blast profile for all samples with the effects of the low density fillers surpassing all others tested.

  4. Experimental characterization of sensor and actuator embedded in intelligent materials

    SciTech Connect

    Burford, M.K.; Murphy, K.A.; Claus, R.O.; Miller, M.S.; Grace, J.L.; Carman, G.P.

    1994-12-31

    The authors report results from a research program which investigating the feasibility of utilizing optical fiber sensors to experimentally verify actuator properties as well as to determine the nonlinear behavior of the actuators. The measurement of longitudinal strain by extrinsic Fabry-Perot interferometers (EFPI`s) is presented for three PZT/material configurations as the voltage applied to the specimen is ramped up and down under various loading and clamping conditions. These arrangements simulate an actuator (1) by itself, (2) embedded in a composite laminate, and (3) attached to a composite laminate. Loaded and unloaded conditions are tested for two configurations to determine the nonlinear effects of loads on the PZT material. Experimental results are presented.

  5. Taguchi method of experimental design in materials education

    NASA Technical Reports Server (NTRS)

    Weiser, Martin W.

    1993-01-01

    Some of the advantages and disadvantages of the Taguchi Method of experimental design as applied to Materials Science will be discussed. This is a fractional factorial method that employs the minimum number of experimental trials for the information obtained. The analysis is also very simple to use and teach, which is quite advantageous in the classroom. In addition, the Taguchi loss function can be easily incorporated to emphasize that improvements in reproducibility are often at least as important as optimization of the response. The disadvantages of the Taguchi Method include the fact that factor interactions are normally not accounted for, there are zero degrees of freedom if all of the possible factors are used, and randomization is normally not used to prevent environmental biasing. In spite of these disadvantages it is felt that the Taguchi Method is extremely useful for both teaching experimental design and as a research tool, as will be shown with a number of brief examples.

  6. Experimental Studies of Carbon Nanotube Materials for Space Radiators

    NASA Technical Reports Server (NTRS)

    SanSoucie, MIchael P.; Rogers, Jan R.; Craven, Paul D.; Hyers, Robert W.

    2012-01-01

    Game ]changing propulsion systems are often enabled by novel designs using advanced materials. Radiator performance dictates power output for nuclear electric propulsion (NEP) systems. Carbon nanotubes (CNT) and carbon fiber materials have the potential to offer significant improvements in thermal conductivity and mass properties. A test apparatus was developed to test advanced radiator designs. This test apparatus uses a resistance heater inside a graphite tube. Metallic tubes can be slipped over the graphite tube to simulate a heat pipe. Several sub ]scale test articles were fabricated using CNT cloth and pitch ]based carbon fibers, which were bonded to a metallic tube using an active braze material. The test articles were heated up to 600 C and an infrared (IR) camera captured the results. The test apparatus and experimental results are presented here.

  7. Experimental characterization of materials subjected to combined loading conditions

    NASA Astrophysics Data System (ADS)

    Andrusca, L.; Goanta, V.; Barsanescu, P. D.; Savin, A.

    2016-08-01

    In real life experience, machine and structure elements are subjected to complex loading history. Combined loading testes facilitate the understanding of materials behavior subjected to multiaxial stress state. In this paper are presented experimental investigations used to evaluate the influence of an initial type of loading on material properties which will be subsequently tested through another load type. Initial tests are tension tests, by different elongations, and subsequent tests are torsion tests, until break. Circular cross section specimens will be used in these tests. Tension tests have been performed on a universal testing machine. Subsequently torsion tests have been conducted through an attachable device. It was found that the energy associated with plastic deformation obtained by subsequent torsional tests has the dominant influence on the material total plastic energy, although initial test was tension.

  8. Quantification of uncertainty of experimental measurement in leaching test on cement-based materials.

    PubMed

    Coutand, M; Cyr, M; Clastres, P

    2011-10-01

    When mineral wastes are reused in construction materials, a current practice is to evaluate their environmental impact using standard leaching test. However, due to the uncertainty of the measurement, it is usually quite difficult to estimate the pollutant potential compared to other materials or threshold limits. The aim of this paper is to give a quantitative evaluation of the uncertainty of leachate concentrations of cement-based materials, as a function of the number of test performed. The relative standard deviations and relative confidence intervals are determined using experimental data in order to give a global evaluation of the uncertainty of leachate concentrations (determination of total relative standard deviation). Various combinations were realized in order to point out the origin of large dispersion of the results (determination of relative standard deviation linked to analytical measured and to leaching procedure), generalisation was suggested and the results were compared to literature. An actual example was given about the introduction of residue (meat and bone meal bottom ash--MBM-BA) in mortar, leaching tests were carried out on various samples with and without residue MBM-BA. In conclusion large dispersion were observed and mainly due to heterogeneity of materials. So heightened attention needed to analyse leaching result on cement-based materials and further more other tests (e.g. ecotoxicology) should be performed to evaluate the environmental effect of these materials.

  9. Dynamic viscoelastic properties of experimental silicone soft lining materials.

    PubMed

    Santawisuk, Wallapat; Kanchanavasita, Widchaya; Sirisinha, Chakrit; Harnirattisai, Choltacha

    2010-08-01

    The purpose of this study was to evaluate the dynamic viscoelastic properties of experimental silicone soft lining materials, Silastic MDX 4-4210 reinforced with silica fillers. Storage modulus (E'), loss modulus (E") and damping factor (tan delta) were determined using a dynamic mechanical analyzer under a deformation strain level of 0.27% at test frequency and a temperature range of 1 Hz and 0 to 60 degrees C, respectively. The degree of silica dispersion was also studied using a field emission scanning electron microscopy (FE-SEM). One-way ANOVA and Tukey's HSD test results indicated that the prepared silicone elastomers provided a significantly greater damping factor, but less storage modulus than GC Reline Soft and Tokuyama Sofreliner Tough (p<0.001). The storage moduli, loss moduli and damping factor of the experimental silicone elastomers increased with increasing amounts of fumed silica. In conclusion, the experimental silicone elastomers revealed acceptable dynamic viscoelastic properties to be used as denture soft lining materials.

  10. Spin glasses: redux: an updated experimental/materials survey

    NASA Astrophysics Data System (ADS)

    Mydosh, J. A.

    2015-05-01

    This article reviews the 40+ year old spin-glass field and one of its earliest model interpretations as a spin density wave. Our description is from an experimental phenomenological point of view with emphasis on new spin glass materials and their relation to topical problems and strongly correlated materials in condensed matter physics. We first simply define a spin glass (SG), give its basic ingredients and explain how the spin glasses enter into the statistical mechanics of classical phase transitions. We then consider the four basic experimental properties to solidly characterize canonical spin glass behavior and introduce the early theories and models. Here the spin density wave (SDW) concept is used to explain the difference between a short-range SDW, i.e. a SG and, in contrast, a long-range SDW, i.e. a conventional magnetic phase transition. We continue with the present state of SG, its massive computer simulations and recent proposals of chiral glasses and quantum SG. We then collect and mention the various SG ‘spin-off’s'. A major section uncovers the fashionable unconventional materials that display SG-like freezing and glassy ground states, such as (high temperature) superconductors, heavy fermions, intermetallics and Heuslers, pyrochlor and spinels, oxides and chalogenides and exotics, e.g. quasicrystals. Some conclusions and future directions complete the review.

  11. Fabrication and test of experimental automotive friction materials

    NASA Technical Reports Server (NTRS)

    Halberstadt, M. L.

    1976-01-01

    Three classes of experimental ingredients having good high temperature stability were substituted, singly and in combination, for corresponding ingredients in a standard friction material. The effects of substitution were evaluated by physical and chemical analysis, and principally by determination of friction and wear properties as a function of temperature on a sample drag dynamometer. The major finding was the demonstration of the potential of potassium titanate fiber for the improvement of a friction material of the secondary lining type. For example, the maintenance of a mean friction coefficient of 0.35 between 232 and 343 C (450 and 650 F) was achieved in the presence of the titanate fiber, as opposed to a value of 0.30 in its absence. Wear improvement of the order of 30 to 40% also becomes possible by proper adjustment of resin content and potassium titanate fiber-to-asbestos ratio.

  12. Experimental determination of efficiency of capping materials during consolidation of metal-contaminated dredged material.

    PubMed

    Eek, Espen; Godøy, Olaug; Aagaard, Per; Breedveld, Gijs D

    2007-10-01

    Capping has received considerable attention as a method to reduce contaminant transport from contaminated sediments and sub-aqueous disposed dredged materials. Consolidation of dredged material after capping can result in a substantial advection of pore water, into or through the capping layer. The effect of two different capping materials (crushed limestone and gneiss) on the transport of heavy metals and phosphorus during consolidation was studied with a novel experimental design. Capped dredged material was placed in a consolidation cell and pore water expelled during the consolidation was collected for chemical analysis. To support interpretation of the results from this test, interactions between the capping material and the dredged material were also studied in batch tests. The study revealed large differences in the capping efficiency (CE) between the two materials. Both materials were efficient caps for Fe and P (CE>99% with 2cm cap), while limestone also was efficient for Mn (CE>92% with 2cm cap). Contrary to what was expected, capping of dredged material with crushed gneiss increased the release of Ca, Mn, Co, Ni, Cd, and Cu, resulting in negative CE. The batch tests showed that leaching from the crushed gneiss was the source of the observed release of metals. The results also show that the high concentrations of heavy metals in the dredged material were immobilised, probably by sulphides. Protection against re-suspension and oxidation will therefore in many cases be the most important effect of the cap. PMID:17631382

  13. Experimental and computing strategies in advanced material characterization problems

    SciTech Connect

    Bolzon, G.

    2015-10-28

    The mechanical characterization of materials relies more and more often on sophisticated experimental methods that permit to acquire a large amount of data and, contemporarily, to reduce the invasiveness of the tests. This evolution accompanies the growing demand of non-destructive diagnostic tools that assess the safety level of components in use in structures and infrastructures, for instance in the strategic energy sector. Advanced material systems and properties that are not amenable to traditional techniques, for instance thin layered structures and their adhesion on the relevant substrates, can be also characterized by means of combined experimental-numerical tools elaborating data acquired by full-field measurement techniques. In this context, parameter identification procedures involve the repeated simulation of the laboratory or in situ tests by sophisticated and usually expensive non-linear analyses while, in some situation, reliable and accurate results would be required in real time. The effectiveness and the filtering capabilities of reduced models based on decomposition and interpolation techniques can be profitably used to meet these conflicting requirements. This communication intends to summarize some results recently achieved in this field by the author and her co-workers. The aim is to foster further interaction between engineering and mathematical communities.

  14. Experimental and computing strategies in advanced material characterization problems

    NASA Astrophysics Data System (ADS)

    Bolzon, G.

    2015-10-01

    The mechanical characterization of materials relies more and more often on sophisticated experimental methods that permit to acquire a large amount of data and, contemporarily, to reduce the invasiveness of the tests. This evolution accompanies the growing demand of non-destructive diagnostic tools that assess the safety level of components in use in structures and infrastructures, for instance in the strategic energy sector. Advanced material systems and properties that are not amenable to traditional techniques, for instance thin layered structures and their adhesion on the relevant substrates, can be also characterized by means of combined experimental-numerical tools elaborating data acquired by full-field measurement techniques. In this context, parameter identification procedures involve the repeated simulation of the laboratory or in situ tests by sophisticated and usually expensive non-linear analyses while, in some situation, reliable and accurate results would be required in real time. The effectiveness and the filtering capabilities of reduced models based on decomposition and interpolation techniques can be profitably used to meet these conflicting requirements. This communication intends to summarize some results recently achieved in this field by the author and her co-workers. The aim is to foster further interaction between engineering and mathematical communities.

  15. Experimental hypervelocity impact effects on simulated planetesimal materials

    SciTech Connect

    Tedeschi, W.J.; Schulze, J.F.; Remo, J.L.; Young, R.P. Jr

    1994-08-01

    Experimental results are presented from a series of hypervelocity impact tests on simulated comet and asteroid materials for the purpose of characterizing their response to hypervelocity kinetic energy impacts. Nine tests were conducted at the Air Force Arnold Engineering Development Center (AEDC) S1 Range Facility on ice, rock, and iron target samples using a spherical 2.39 mm diameter aluminum impactor (0.0192 gm) at impact velocities of from 7.6 to 8.4 km/sec. The test objectives were to collect target response phenomenology data on cratering, momentum deposition and enhancement, target fragmentation, and material response under hypervelocity impact loading conditions. A carefully designed ballistic pendulum was used to measure momentum deposition into the targets. Observations and measurements of the impacted samples provide important insights into the response of these materials to kinetic energy impacts, especially in regards to unexpectedly large measured values of momentum enhancement to some of the targets. Such information is required to allow us to successfully deflect or fragment comets or asteroids which might someday be detected on collision trajectories with Earth.

  16. Evaluation of advanced materials through experimental mechanics and modelling

    NASA Technical Reports Server (NTRS)

    Yang, Yii-Ching

    1993-01-01

    Composite materials have been frequently used in aerospace vehicles. Very often defects are inherited during the manufacture and damages are inherited during the construction and services. It becomes critical to understand the mechanical behavior of such composite structure before it can be further used. One good example of these composite structures is the cylindrical bottle of solid rocket motor case with accidental impact damages. Since the replacement of this cylindrical bottle is expensive, it is valuable to know how the damages affects the material, and how it can be repaired. To reach this goal, the damage must be characterized and the stress/strain field must be carefully analyzed. First the damage area, due to impact, is surveyed and identified with a shearography technique which uses the principle of speckle shearing interferometry to measure displacement gradient. Within the damage area of a composite laminate, such as the bottle of solid rocket motor case, all layers are considered to be degraded. Once a lamina being degraded the stiffness as well as strength will be drastically decreased. It becomes a critical area of failure to the whole bottle. And hence the stress/strain field within and around a damage should be accurately evaluated for failure prediction. To investigate the stress/strain field around damages a Hybrid-Numerical method which combines experimental measurement and finite element analysis is used. It is known the stress or strain at the singular point can not be accurately measured by an experimental technique. Nevertheless, if the location is far away from the singular spot, the displacement can be found accurately. Since it reflects the true displacement field locally regardless of the boundary conditions, it is an excellent input data for a finite element analysis to replace the usually assumed boundary conditions. Therefore, the Hybrid-Numerical method is chosen to avoid the difficulty and to take advantage of both experimental

  17. Evaluation of advanced materials through experimental mechanics and modelling

    NASA Astrophysics Data System (ADS)

    Yang, Yii-Ching

    1993-11-01

    Composite materials have been frequently used in aerospace vehicles. Very often defects are inherited during the manufacture and damages are inherited during the construction and services. It becomes critical to understand the mechanical behavior of such composite structure before it can be further used. One good example of these composite structures is the cylindrical bottle of solid rocket motor case with accidental impact damages. Since the replacement of this cylindrical bottle is expensive, it is valuable to know how the damages affects the material, and how it can be repaired. To reach this goal, the damage must be characterized and the stress/strain field must be carefully analyzed. First the damage area, due to impact, is surveyed and identified with a shearography technique which uses the principle of speckle shearing interferometry to measure displacement gradient. Within the damage area of a composite laminate, such as the bottle of solid rocket motor case, all layers are considered to be degraded. Once a lamina being degraded the stiffness as well as strength will be drastically decreased. It becomes a critical area of failure to the whole bottle. And hence the stress/strain field within and around a damage should be accurately evaluated for failure prediction. To investigate the stress/strain field around damages a Hybrid-Numerical method which combines experimental measurement and finite element analysis is used. It is known the stress or strain at the singular point can not be accurately measured by an experimental technique. Nevertheless, if the location is far away from the singular spot, the displacement can be found accurately. Since it reflects the true displacement field locally regardless of the boundary conditions, it is an excellent input data for a finite element analysis to replace the usually assumed boundary conditions. Therefore, the Hybrid-Numerical method is chosen to avoid the difficulty and to take advantage of both experimental

  18. Experimental Observations on Material Damping at Cryogenic Temperatures

    NASA Technical Reports Server (NTRS)

    Peng, Chia-Yen; Levine, Marie; Shido, Lillian; Leland, Robert

    2004-01-01

    This paper describes a unique experimental facility designed to measure damping of materials at cryogenic temperatures for the Terrestrial Planet Finder (TPF) mission at the Jet Propulsion Laboratory. The test facility removes other sources of damping in the measurement by avoiding frictional interfaces, decoupling the test specimen from the support system, and by using a non-contacting measurement device. Damping data reported herein are obtained for materials (Aluminum, Aluminum/Terbium/Dysprosium, Titanium, Composites) vibrating in free-free bending modes with low strain levels (< 10(exp -6) ppm). The fundamental frequencies of material samples are ranged from 14 to 202 Hz. To provide the most beneficial data relevant to TPF-like precision optical space missions, the damping data are collected from room temperatures (around 293 K) to cryogenic temperatures (below 40 K) at unevenly-spaced intervals. More data points are collected over any region of interest. The test data shows a significant decrease in viscous damping at cryogenic temperatures. The cryogenic damping can be as low as 10(exp -4) %, but the amount of the damping decrease is a function of frequency and material. However, Titanium 15-3-3-3 shows a remarkable increase in damping at cryogenic temperatures. It demonstrates over one order of magnitude increase in damping in comparison to Aluminum 6061-T6. Given its other properties (e.g., good stiffness and low conductivity) this may prove itself to be a good candidate for the application on TPF. At room temperatures, the test data are correlated well with the damping predicted by the Zener theory. However, large discrepancies at cryogenic temperatures between the Zener theory and the test data are observed.

  19. Degradation of experimental composite materials and in vitro wear simulation

    NASA Astrophysics Data System (ADS)

    Givan, Daniel Allen

    2001-12-01

    The material, mechanical, and clinical aspects of surface degradation of resin composite dental restorative materials by in vitro wear simulation continues to be an area of active research. To investigate wear mechanisms, a series of experimental resin composites with variable and controlled filler particle shape and loading were studied by in vitro wear simulation. The current investigation utilized a simulation that isolated the wear environment, entrapped high and low modulus debris, and evaluated the process including machine and fluid flow dynamics. The degradation was significantly affected by filler particle shape and less by particle loading. The spherical particle composites demonstrated wear loss profiles suggesting an optimized filler loading may exist. This was also demonstrated by the trends in the mechanical properties. Very little difference in magnitude was noted for the wear of irregular particle composites as a function of particulate size; and as a group they were more wear resistant than spherical particle composites. This was the result of different mechanisms of wear that were correlated with the three-dimensional particle shape. The abrasive effects of the aggregate particles and the polymeric stabilization of the irregular shape versus the destabilization and "plucking" of the spherical particles resulted in an unprotected matrix that accounted for significantly greater wear of spherical composite. A model and analysis was developed to explain the events associated with the progressive material wear loss. The initial phase was explained by fatigue-assisted microcracking and loss of material segments in a zone of high stress immediately beneath a point of high stress contact. The early phase was characterized by the development of a small facet primarily by fatigue-assisted microcracking. Although the translation effects were minimal, some three-body and initial two-body wear events were also present. In the late phases, the abrasive effects

  20. Experimental Investigation of Ice Phase Change Material Heat Exchangers

    NASA Technical Reports Server (NTRS)

    Leimkuehler, Thomas O.; Stephan, Ryan A.

    2012-01-01

    Phase change materials (PCM) may be useful for spacecraft thermal control systems that involve cyclical heat loads or cyclical thermal environments. Thermal energy can be stored in the PCM during peak heat loads or in adverse thermal environments. The stored thermal energy can then be released later during minimum heat loads or in more favorable thermal environments. This can result in a decreased turndown ratio for the radiator and a reduced system mass. The use of water as a PCM rather than the more traditional paraffin wax has the potential for significant mass reduction since the latent heat of formation of water is approximately 70% greater than that of wax. One of the potential drawbacks of using ice as a PCM is its potential to rupture its container as water expands upon freezing. In order to develop a space qualified ice PCM heat exchanger, failure mechanisms must first be understood. Therefore, a methodical experimental investigation has been undertaken to demonstrate and document specific failure mechanisms due to ice expansion in the PCM. A number of ice PCM heat exchangers were fabricated and tested. Additionally, methods for controlling void location in order to reduce the risk of damage due to ice expansion were investigated. This paper presents an overview of the results of this investigation from the past three years.

  1. Experimental Investigation of Ice Phase Change Material Heat Exchangers

    NASA Technical Reports Server (NTRS)

    Leimkuehler, Thomas O.; Stephan, Ryan A.

    2011-01-01

    Phase change materials (PCM) may be useful for spacecraft thermal control systems that involve cyclical heat loads or cyclical thermal environments. Thermal energy can be stored in the PCM during peak heat loads or in adverse thermal environments. The stored thermal energy can then be released later during minimum heat loads or in more favorable thermal environments. This can result in a decreased turndown ratio for the radiator and a reduced system mass. The use of water as a PCM rather than the more traditional paraffin wax has the potential for significant mass reduction since the latent heat of formation of water is approximately 70% greater than that of wax. One of the potential drawbacks of using ice as a PCM is its potential to rupture its container as water expands upon freezing. In order to develop a space qualified ice PCM heat exchanger, failure mechanisms must first be understood. Therefore, a methodical experimental investigation has been undertaken to demonstrate and document specific failure mechanisms due to ice expansion in the PCM. A number of ice PCM heat exchangers were fabricated and tested. Additionally, methods for controlling void location in order to reduce the risk of damage due to ice expansion were investigated. This paper presents an overview of the results of this investigation from the past three years.

  2. Shear fractures in anisotropic ductile materials: An experimental approach

    NASA Astrophysics Data System (ADS)

    Gomez-Rivas, Enrique; Griera, Albert

    2012-01-01

    Analogue models have been used to investigate the influence of planar mechanical anisotropy on the orientation of shear fractures in an elastoviscous-brittle material. Multilayered models consisting of a mixture of plasticine, vaseline and preferentially-oriented paper flakes have been coaxially deformed for this purpose. The evolution of the orientation, length and connectivity of fracture sets has been systematically analysed with progressive coaxial deformation. The experimental results show that the orientation of fractures with respect to the deformation axes depends on the orientation of transverse anisotropy. Two symmetrical sets of shear fractures are formed in models with layering parallel to the extension axis X, while the fracture network is asymmetrical with respect to the deformation axes for cases with oblique anisotropy. The average dihedral angles between fracture sets are higher than 100°, with the obtuse bisector between the two sets oriented perpendicular to layers. The stress fields calculated from fracture data differ from the boundary conditions applied by the deformation apparatus. This misorientation is related to the degree of anisotropy. In models with high oblique anisotropy both fracture arrays rotate in a dextral sense together with layers towards the X-axis, indicating that the presence of a strong anisotropy controls their evolution with progressive deformation.

  3. Experimental studies on the kinematics of cutting in granular materials

    NASA Astrophysics Data System (ADS)

    Murthy, T. G.; Saldana, C.; Yadav, S.; Du, F.

    2013-06-01

    Slow flow in granular materials is characterized by high solid fraction and sustained inter-particle interaction. The kinematics of trawling or cutting is encountered in processes such as locomotion of organisms in sand; trawl gear movement on a soil deposit; plow movement; movement of rovers, earth moving equipment etc. Additionally, this configuration is very akin to shallow drilling configuration encountered in the mining and petroleum industries. An experimental study has been made in order to understand velocity and deformation fields in cutting of a model rounded sand. Under nominal plane strain conditions, sand is subjected to orthogonal cutting at different tool-rake angles. High-resolution optical images of the region of cutting were obtained during the flow of the granular ensemble around the tool. Interesting kinematics underlying the formation of a chip and the evolution of the deformation field is seen in these experiments. These images are also analyzed using a PIV algorithm and detailed information of the deformation parameters such as velocity, strain rate and volume change is obtained.

  4. Thermal mapping and trends of Mars analog materials in sample acquisition operations using experimentation and models

    NASA Astrophysics Data System (ADS)

    Szwarc, Timothy; Hubbard, Scott

    2014-09-01

    The effects of atmosphere, ambient temperature, and geologic material were studied experimentally and using a computer model to predict the heating undergone by Mars rocks during rover sampling operations. Tests were performed on five well-characterized and/or Mars analog materials: Indiana limestone, Saddleback basalt, kaolinite, travertine, and water ice. Eighteen tests were conducted to 55 mm depth using a Mars Sample Return prototype coring drill, with each sample containing six thermal sensors. A thermal simulation was written to predict the complete thermal profile within each sample during coring and this model was shown to be capable of predicting temperature increases with an average error of about 7%. This model may be used to schedule power levels and periods of rest during actual sample acquisition processes to avoid damaging samples or freezing the bit into icy formations. Maximum rock temperature increase is found to be modeled by a power law incorporating rock and operational parameters. Energy transmission efficiency in coring is found to increase linearly with rock hardness and decrease by 31% at Mars pressure.

  5. Experimental characterization of energetic material dynamics for multiphase blast simulation.

    SciTech Connect

    Beresh, Steven Jay; Wagner, Justin L.; Kearney, Sean Patrick; Wright, Elton K.; Baer, Melvin R.; Pruett, Brian Owen Matthew

    2011-09-01

    Currently there is a substantial lack of data for interactions of shock waves with particle fields having volume fractions residing between the dilute and granular regimes, which creates one of the largest sources of uncertainty in the simulation of energetic material detonation. To close this gap, a novel Multiphase Shock Tube has been constructed to drive a planar shock wave into a dense gas-solid field of particles. A nearly spatially isotropic field of particles is generated in the test section by a gravity-fed method that results in a spanwise curtain of spherical 100-micron particles having a volume fraction of about 19%. Interactions with incident shock Mach numbers of 1.66, 1.92, and 2.02 were achieved. High-speed schlieren imaging simultaneous with high-frequency wall pressure measurements are used to reveal the complex wave structure associated with the interaction. Following incident shock impingement, transmitted and reflected shocks are observed, which lead to differences in particle drag across the streamwise dimension of the curtain. Shortly thereafter, the particle field begins to propagate downstream and spread. For all three Mach numbers tested, the energy and momentum fluxes in the induced flow far downstream are reduced about 30-40% by the presence of the particle field. X-Ray diagnostics have been developed to penetrate the opacity of the flow, revealing the concentrations throughout the particle field as it expands and spreads downstream with time. Furthermore, an X-Ray particle tracking velocimetry diagnostic has been demonstrated to be feasible for this flow, which can be used to follow the trajectory of tracer particles seeded into the curtain. Additional experiments on single spherical particles accelerated behind an incident shock wave have shown that elevated particle drag coefficients can be attributed to increased compressibility rather than flow unsteadiness, clarifying confusing results from the historical database of shock tube

  6. EXPERIMENTAL STUDIES ON PARTICLE IMPACTION AND BOUNCE: EFFECTS OF SUBSTRATE DESIGN AND MATERIAL. (R825270)

    EPA Science Inventory

    This paper presents an experimental investigation of the effects of impaction substrate designs and material in reducing particle bounce and reentrainment. Particle collection without coating by using combinations of different impaction substrate designs and surface materials was...

  7. Experimental data for new fire-retardant materials

    NASA Technical Reports Server (NTRS)

    Supkis, D. E.

    1977-01-01

    Report contains evaluations of flammability and physical properties of twenty-four upholstery and furnishing materials, such as those used in commercial aircraft. Data presented include degradation upon heating, limited oxygen indices, smoke generation, flammability afterglow, and char length.

  8. Experimental study of optical storage characteristics of photochromic material: pyrrylfulgide

    NASA Astrophysics Data System (ADS)

    Lei, Ming; Yao, Baoli; Chen, Yi; Han, Yong; Wang, Congmin; Wang, Yingli; Menke, Neimule; Chen, Guofu; Fan, Meigong

    2003-04-01

    Optical data storage is a frontier in the information science. Currently, there are mainly two kinds of storage materials, i.e., thermal-optic and photonic materials. The storage methods are divided into serial and parallel modes. In the market, the mature technique is CD-RW, which uses the thermal-optic material and serial method. The storage density of the CD-RW is restricted by the size of material particles, the conduction of heat, etc. Besides, the recording speed is seriously limited by the process of heating. Photonic materials and parallel method will be the trend in the optical data storage. Because it is based on the photon reaction on the molecule scale, the storage density and speed will be greatly increased. In this paper, a new kind of organic photochromic material -- pyrrylfulgide was studied. A parallel optical data storage system was established. Using the pyrrylfulgide/PMMA film as a recording medium, micro-images and binary digital information could be recorded, readout and erased in this parallel system. The recorded information on the film can be kept for at least 8 months in dark at room temperature. So far, the storage density is 3 x 107 bit/cm2.

  9. The behavior of delaminations in composite materials - experimental results

    NASA Astrophysics Data System (ADS)

    Chermoshentseva, A. S.; Pokrovskiy, A. M.; Bokhoeva, L. A.

    2016-02-01

    Delamination is one of the most common failure modes of composite materials. It may occur as a consequence of imperfections in the production process or the effects of external factors during the operational life of the composite laminates, such as the impact by foreign objects. This paper presents the results of mechanical tests and the optimum degrees of filling the composite materials (CM) with hydrophobic powder (Tarkosil T-20) depending on the latter mass concentration. The results present test samples of the CM with the underlying interlayer defects. The samples were fabricated of twenty-ply pre-preg (fiberglass or carbon fiber). The industrial grade glass is T-25 (VM) specification 6-11-380-76. The composite materials have nanosized additives in structure. The volume concentration of nanopowders is varying from 0.1% to 0.5%. This kind of research has been done for the first time.

  10. Experimental and Analytical Studies for a Computational Materials Program

    NASA Technical Reports Server (NTRS)

    Knauss, W. G.

    1999-01-01

    The studies supported by Grant NAG1-1780 were directed at providing physical data on polymer behavior that would form the basis for computationally modeling these types of materials. Because of ongoing work in polymer characterization this grant supported part of a larger picture in this regard. Efforts went into two combined areas of their time dependent mechanical response characteristics: Creep properties on the one hand, subject to different volumetric changes (nonlinearly viscoelastic behavior) and time or frequency dependence of dilatational material behavior. The details of these endeavors are outlined sufficiently in the two appended publications, so that no further description of the effort is necessary.

  11. 34 CFR 98.3 - Access to instructional material used in a research or experimentation program.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 34 Education 1 2011-07-01 2011-07-01 false Access to instructional material used in a research or... RIGHTS IN RESEARCH, EXPERIMENTAL PROGRAMS, AND TESTING § 98.3 Access to instructional material used in a research or experimentation program. (a) All instructional material—including teachers' manuals,...

  12. 34 CFR 98.3 - Access to instructional material used in a research or experimentation program.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 34 Education 1 2014-07-01 2014-07-01 false Access to instructional material used in a research or experimentation program. 98.3 Section 98.3 Education Office of the Secretary, Department of Education STUDENT RIGHTS IN RESEARCH, EXPERIMENTAL PROGRAMS, AND TESTING § 98.3 Access to instructional material used in...

  13. 34 CFR 98.3 - Access to instructional material used in a research or experimentation program.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 34 Education 1 2013-07-01 2013-07-01 false Access to instructional material used in a research or experimentation program. 98.3 Section 98.3 Education Office of the Secretary, Department of Education STUDENT RIGHTS IN RESEARCH, EXPERIMENTAL PROGRAMS, AND TESTING § 98.3 Access to instructional material used in...

  14. 34 CFR 98.3 - Access to instructional material used in a research or experimentation program.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 34 Education 1 2012-07-01 2012-07-01 false Access to instructional material used in a research or... RIGHTS IN RESEARCH, EXPERIMENTAL PROGRAMS, AND TESTING § 98.3 Access to instructional material used in a research or experimentation program. (a) All instructional material—including teachers' manuals,...

  15. Stuff- The Materials that Shape our World - Experimental Learning Opportunities

    SciTech Connect

    Rosenstein, Pam

    2012-04-30

    Making Stuff is a four-part series that explores how materials changed history and are shaping the future. To further enhance public engagement in and understanding of materials science, the project convened an extensive network of community coalitions across the country that hosted Making Stuff outreach activities and events, science cafes, and educator workshops in their local areas. Department Of Energy funding enabled us to increase the number of communities formally involved in the project, from 10 to 20 community hubs. Department of Energy funding also made it possible to develop a collection of materials science resources, activities and hands-on demonstrations for use in a variety of formal and informal settings, and Making Stuff activities were presented at science conferences and festivals around the country. The design, printing and national dissemination of the Making Stuff afterschool activity guide were also developed with DOE funding, as well as professional webinar trainings for scientists and educators to help facilitate many of the community activities and other online and print materials. Thanks to additional funding from the Department of Energy, we were able to expand the reach and scope of the project's outreach plan, specifically in the areas of: 1) content development, 2) training/professional development, 3) educational activities and 4) community partnerships. This report documents how the following DOE project goals were met: (1) Train scientists and provide teachers and informal educators with resources to engage youth with age appropriate information about materials science; (2) Provide activities and resources to five selected communities with ties to DOE researchers; (3) Increase interest in STEM.

  16. Experimental Investigation of Textile Composite Materials Using Moire Interferometry

    NASA Technical Reports Server (NTRS)

    Ifju, Peter G.

    1995-01-01

    The viability as an efficient aircraft material of advanced textile composites is currently being addressed in the NASA Advanced Composites Technology (ACT) Program. One of the expected milestones of the program is to develop standard test methods for these complex material systems. Current test methods for laminated composites may not be optimum for textile composites, since the architecture of the textile induces nonuniform deformation characteristics on the scale of the smallest repeating unit of the architecture. The smallest repeating unit, also called the unit cell, is often larger than the strain gages used for testing of tape composites. As a result, extending laminated composite test practices to textiles can often lead to pronounced scatter in material property measurements. It has been speculated that the fiber architectures produce significant surface strain nonuniformities, however, the magnitudes were not well understood. Moire interferometry, characterized by full-field information, high displacement sensitivity, and high spatial resolution, is well suited to document the surface strain on textile composites. Studies at the NASA Langley Research Center on a variety of textile architectures including 2-D braids and 3-D weaves, has evidenced the merits of using moire interferometry to guide in test method development for textile composites. Moire was used to support tensile testing by validating instrumentation practices and documenting damage mechanisms. It was used to validate shear test methods by mapping the full-field deformation of shear specimens. Moire was used to validate open hole tension experiments to determine the strain concentration and compare then to numeric predictions. It was used for through-the-thickness tensile strength test method development, to verify capabilities for testing of both 2-D and 3-D material systems. For all of these examples, moire interferometry provided vision so that test methods could be developed with less

  17. New suture materials for midline laparotomy closure: an experimental study

    PubMed Central

    2014-01-01

    Background Midline laparotomy closure carries a significant risk of incisional hernia. This study examines the behavior of two new suture materials, an elastic material, polyurethane (PUe), and a barbed polydioxanone (PDXb) suture thread in a rabbit model of midline incision closure. Methods Three 2-cm midline incisions were made in 68 New Zealand White rabbits. The incisions were closed by running suture using four 3/0 threads: polypropylene (PP) (Surgipro®, Covidien), PUe (Assuplus®, Assut Europe), PDX (Assufil®, Assut Europe) or PDXb (Filbloc®, Assut Europe). Animals in each suture group were euthanized 3 weeks and 6 months after surgery. Histological sections of the tissue-embedded sutures were subjected to morphological, collagen expression, macrophage response and uniaxial tensiometry studies. Results No signs of wound dehiscence or complications were observed. At 3 weeks, all sutures were surrounded by connective tissue composed mainly of collagen III. PUe showed greater collagen I expression than the other sutures. All sutures elicited a macrophage response that diminished from 3 weeks to 6 months (p < 0.001). This response was similar for the non-reabsorbable sutures (PP and PUe) yet PDXb showed a significantly greater response than the other reabsorbable suture (PDX) at 3 weeks (p < 0.01). At this early time point, the tensile strength of PUe was similar to that of control intact tissue (p > 0.05). Conclusion Three weeks after surgery, PUe revealed more collagen I deposition than the remaining materials and this translated to a similar biomechanical behavior to linea alba, that could avoid the appearance of short term dehiscences and thus reduce the incidence of incisional hernia. PDXb provides no additional advantages in their behavior regarding PDX suture. PMID:25231161

  18. 27 CFR 24.249 - Experimentation with new treating material or process.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... treating material or process. 24.249 Section 24.249 Alcohol, Tobacco Products and Firearms ALCOHOL AND... Wine § 24.249 Experimentation with new treating material or process. (a) General. The proprietor may... treating material or process as the appropriate TTB officer finds may be conducted in a manner that...

  19. Structures and Materials Experimental Facilities and Capabilities Catalog

    NASA Technical Reports Server (NTRS)

    Horta, Lucas G. (Compiler); Kurtz-Husch, Jeanette D. (Compiler)

    2000-01-01

    The NASA Center of Excellent for Structures and Materials at Langley Research Center is responsible for conducting research and developing useable technology in the areas of advanced materials and processing technologies, durability, damage tolerance, structural concepts, advanced sensors, intelligent systems, aircraft ground operations, reliability, prediction tools, performance validation, aeroelastic response, and structural dynamics behavior for aerospace vehicles. Supporting the research activities is a complementary set of facilities and capabilities documented in this report. Because of the volume of information, the information collected was restricted in most cases to one page. Specific questions from potential customers or partners should be directed to the points of contacts provided with the various capabilities. Grouping of the equipment is by location as opposed to function. Geographical information of the various buildings housing the equipment is also provided. Since this is the first time that such an inventory is ever collected at Langley it is by no means complete. It is estimated that over 90 percent of the equipment capabilities at hand are included but equipment is continuously being updated and will be reported in the future.

  20. [Integration properties of bone substitute materials. Experimental studies on animals].

    PubMed

    Günther, K P; Scharf, H P; Pesch, H J; Puhl, W

    1998-02-01

    In order to avoid the potential risks of disease transmission in allograft surgery, numerous substitute materials have been described. As the biological response to implant materials is different, we undertook the following study to assess type and amount of bone ingrowth in CaP-ceramics. 105 cylindrical bone defects with a diameter of 5.4 mm were created surgically in the femoral condyles of 53 skeletal mature NZW rabbits. The defects were filled with crushed coralline hydroxyapatite (HA) implants (n = 21), synthetically produced hydroxyapatite (n = 21) and surface-modified alpha-Tricalciumphosphate (TCP) grains (n = 21). 21 defects were left empty and other drill holes were filled with rabbit cancellous bone cylinders (n = 21) after 3 months of cryopreservation at -78 degrees C without sterilization. Following observation periods of 2, 4, 6, 8, 12, 26 and 52 weeks the femoral condyles were harvested for histological evaluation and quantitative analysis of bone ingrowth. Woven bone formation at implant periphery can be observed in all substances as early as 2 weeks postoperatively. At 4-week-intervals cryopreserved allografts show new bone apposition on surfaces of necrotic trabeculae and graft-host junctions by a predominantly osteoblastic reaction at the periphery of all cylinders, while in HA- and TCP-grains early bone formation in the center of drill holes is detectable as well. There is a direct contact between HA-/TCP-particles and newly formed bone without fibrous tissue formation at the implant surfaces. Central new bone formation in rabbit allografts can be observed after 6 to 8 weeks together with a secondary osteoclastic resorption of necrotic transplant trabeculae. The result of this remodeling process is a complete degradation of transplant cylinders with reorganization of vital trabeculae oriented in a mature pattern after 12 to 26 weeks. In contrast the HA- and TCP-implants did not show any signs of resorption. PMID:9530667

  1. Analytical and experimental studies for thermal plasma processing of materials

    NASA Astrophysics Data System (ADS)

    Work continued on thermal plasma processing of materials. This quarter, ceramic powders of carbides, aluminum nitride, oxides, solids solutions, magnetic and non magnetic spinels, superconductors, and composites have been successfully synthesized in a Triple DC Torch Plasma Jet Reactor (TTPR) and in a single DC Plasma Jet Reactor. All the ceramic powders with the exception of AIN were synthesized using a novel injection method developed to overcome the problems associated with solid injection, in particular for the single DC plasma jet reactor, and to realize the benefits of gas phase reactions. Also, initial experiments have been performed for the deposition of diamond coatings on Si wafers using the TTPR with methane as the carbon source. Well faceted diamond crystallites were deposited on the surface of the wafers, forming a continuous one particle thick coating. For measuring temperature and velocity fields in plasma systems, enthalpy probes have been developed and tested. The validity has been checked by performing energy and mass flux balances in an argon plasma jet operated in argon atmosphere. Total Gibbs free energy minimization calculations using a quasi-equilibrium modification have been applied to simulate several chemical reactions. Plasma reactor modelling has been performed for the counter-flow liquid injection plasma synthesis experiment. Plasma diagnostics has been initiated to determine the pressure gradient in the coalesced part of the plasma jet. The pressure gradient drives the diffusion of chemical species which ultimately controls the chemical reactions.

  2. Experimental space weathering of regolith material. [Abstract only

    NASA Technical Reports Server (NTRS)

    Mckay, D. S.; Allen, C. C.

    1994-01-01

    Significant advances in the understanding of space weathering processes were recently reported. Submicroscopic iron blebs were produced in lunar simulant glass and natural terrestrial minerals by high-temperature reduction in controlled atmosphere furnaces. These experiments altered the samples' optical properties and microtextures so that they resembled those of extremely mature lunar soil. The results contributed to a revised model for natural reduction in the regolith. Subsequently, supporting results were obtained by reduction of lunar samples. Research to date has focused on reduction of three lunar surface components: basalt, pyroclastic glass, and mare soil. An extensive set of H reduction experiments with simulants has led to a detailed understanding of reaction mechanisms and kinetics. Reduction experiments using lunar basalt were recently conducted by Carbotek. Reduced samples from these test were analyzed. Reduction experiments on lunar glass 74220 were run at temperatures of 900-1100 C. Reduction efficiency of volcanic glass proved to be a function of the sample's FeO abundance and reaction temperature. We also reduced mare soil 75061 at temperatures of 900-1050 C. Partial reduction of FeO in olivine and pyroxene occurred, but was slower and less complete than reduction of ilmenite. Our experiments on simulants and lunar samples have indicated that the most readily reduced phases in the regolith are ilmenite and glass. Based on initial tests with simulants we proposed refinements to the accepted model for space weathering of the regolith. The impact of a micrometeoroid flash heats and melts and ejects from the impact point a small volume of soil that contains trapped solar wind H and C. Reduction occurs rapidly, while the melt volume is still in motion. When a droplet encounters unmelted soil, it envelopes cold mineral grains. The melt is chilled rapidly. Our analyses of experimentally reduced lunar basalt, glass, and mare soil support the proposed

  3. Form and Actuality

    NASA Astrophysics Data System (ADS)

    Bitbol, Michel

    A basic choice underlies physics. It consists of banishing actual situations from theoretical descriptions, in order to reach a universal formal construct. Actualities are then thought of as mere local appearances of a transcendent reality supposedly described by the formal construct. Despite its impressive success, this method has left major loopholes in the foundations of science. In this paper, I document two of these loopholes. One is the problem of time asymmetry in statistical thermodynamics, and the other is the measurement problem of quantum mechanics. Then, adopting a broader philosophical standpoint, I try to turn the whole picture upside down. Here, full priority is given to actuality (construed as a mode of the immanent reality self-reflectively being itself) over formal constructs. The characteristic aporias of this variety of "Copernican revolution" are discussed.

  4. Experimental investigations and numerical simulations of notch effect in cellular plastic materials

    NASA Astrophysics Data System (ADS)

    Marsavina, L.; Linul, E.; Voiconi, T.; Negru, R.

    2016-04-01

    Cellular plastics are light weight structures with many applications in civil, aeronautical, automotive and mechanical engineering. Properties of cellular materials depend on the properties of the solid material, on the shape and dimensions of the cellular structure and on the relative density of the cellular material. Most of cellular plastic materials are crushing in compression and have a brittle behavior in tension. The effect of notches represents an important issue in such materials, taking into account that for packing applications for example, notches/holes should be introduced in the cellular material. This paper investigates the effect of notches in compression for three different densities 100, 145 and 300 kg/m3 polyurethane (PUR) foams. Experimental investigations were performed on rectangular blocks of 100×100×25 mm with 16, 28 and 40 mm central holes. The mechanism of damage was monitored with an IR camera FLIR A40M. Purpose of the numerical simulations was to calibrate a material model, based on compression test for un-notched specimens using the CRUSHABLE FOAM models implemented in ABAQUS SIMULIA. Then the material models were used to simulate the experimental tests on notched blocks. Good agreement was obtained for the load - displacement curves obtained experimentally and from simulation. Also the plastic deformation patterns observed experimentally by IR thermograpghy were obtained numerically using the CRUSHABLE FOAM material model.

  5. Experimental study of the thermal stability of materials in high temperature oxygen-containing media

    NASA Technical Reports Server (NTRS)

    Abaltusov, Y. Y.; Bagramyan, A. R.; Grishin, A. M.; Yukhvid, V. I.

    1986-01-01

    An experimental study is made of the interaction of several materials with a high temperature medium containing oxygen. The temperature of the surface was measured as a function of time. It is found that the higher the velocity of mass removal from the surface, the more effective is the material from the viewpoint of heat resistance.

  6. Analysis of the absorptive behavior of photopolymer materials. Part II. Experimental validation

    NASA Astrophysics Data System (ADS)

    Li, Haoyu; Qi, Yue; Tolstik, Elen; Guo, Jinxin; Sheridan, John T.

    2015-01-01

    In the first part of this paper, a model describing photopolymer materials, which incorporates both the physical electromagnetic and photochemical effects taking place, was developed. This model is now validated by applying it to fit experimental data for two different types of photopolymer materials. The first photopolymer material, acrylamide/polyvinyl alcohol, is studied when four photosensitizers are used, i.e. Erythrosine B, Eosin Y, Phloxine B and Rose Bengal. The second type of photopolymer material involves phenanthrenequinone in a polymethylmethacrylate matrix. Using our model, the values of physical parameters, are extracted by numerical fitting experimentally obtained normalized transmittance growth curves. Experimental data sets for different exposure intensities, dye concentrations, and exposure geometries are studied. The advantages of our approach are demonstrated and it is shown that the parameters proposed by us to quantify the absorptive behavior in our model are both physical and can be estimated.

  7. Low-cost phase change material as an energy storage medium in building envelopes: Experimental and numerical analyses

    SciTech Connect

    Biswas, Kaushik; Abhari, Ramin

    2014-10-03

    A promising approach to increasing the energy efficiency of buildings is the implementation of a phase change material (PCM) in the building envelope. Numerous studies over the last two decades have reported the energy saving potential of PCMs in building envelopes, but their wide application has been inhibited, in part, by their high cost. This article describes a novel PCM made of naturally occurring fatty acids/glycerides trapped into high density polyethylene (HDPE) pellets and its performance in a building envelope application. The PCM-HDPE pellets were mixed with cellulose insulation and then added to an exterior wall of a test building in a hot and humid climate, and tested over a period of several months, To demonstrate the efficacy of the PCM-enhanced cellulose insulation in reducing the building envelope heat gains and losses, side-by-side comparison was performed with another wall section filled with cellulose-only insulation. Further, numerical modeling of the test wall was performed to determine the actual impact of the PCM-HDPE pellets on wall-generated heating and cooling loads and the associated electricity consumption. The model was first validated using experimental data and then used for annual simulations using typical meteorological year (TMY3) weather data. Furthermore, this article presents the experimental data and numerical analyses showing the energy-saving potential of the new PCM.

  8. Low-cost phase change material as an energy storage medium in building envelopes: Experimental and numerical analyses

    DOE PAGES

    Biswas, Kaushik; Abhari, Ramin

    2014-10-03

    A promising approach to increasing the energy efficiency of buildings is the implementation of a phase change material (PCM) in the building envelope. Numerous studies over the last two decades have reported the energy saving potential of PCMs in building envelopes, but their wide application has been inhibited, in part, by their high cost. This article describes a novel PCM made of naturally occurring fatty acids/glycerides trapped into high density polyethylene (HDPE) pellets and its performance in a building envelope application. The PCM-HDPE pellets were mixed with cellulose insulation and then added to an exterior wall of a test buildingmore » in a hot and humid climate, and tested over a period of several months, To demonstrate the efficacy of the PCM-enhanced cellulose insulation in reducing the building envelope heat gains and losses, side-by-side comparison was performed with another wall section filled with cellulose-only insulation. Further, numerical modeling of the test wall was performed to determine the actual impact of the PCM-HDPE pellets on wall-generated heating and cooling loads and the associated electricity consumption. The model was first validated using experimental data and then used for annual simulations using typical meteorological year (TMY3) weather data. Furthermore, this article presents the experimental data and numerical analyses showing the energy-saving potential of the new PCM.« less

  9. Experimental Determination of Damage Threshold Characteristics of IR Compatible Optical Materials

    SciTech Connect

    Soong, Ken

    2011-05-20

    The accelerating gradient in a laser-driven dielectric accelerating structure is often limited by the laser damage threshold of the structure. For a given laser-driven dielectric accelerator design, we can maximize the accelerating gradient by choosing the best combination of the accelerator's constituent material and operating wavelength. We present here a model of the damage mechanism from ultrafast infrared pulses and compare that model with experimental measurements of the damage threshold of bulk silicon. Additionally, we present experimental measurements of a variety of candidate materials, thin films, and nanofabricated accelerating structures.

  10. Experimental parameter estimation method for nonlinear viscoelastic composite material models: an application on arterial tissue.

    PubMed

    Sunbuloglu, Emin; Bozdag, Ergun; Toprak, Tuncer; Islak, Civan

    2013-01-01

    This study is aimed at setting a method of experimental parameter estimation for large-deforming nonlinear viscoelastic continuous fibre-reinforced composite material model. Specifically, arterial tissue was investigated during experimental research and parameter estimation studies, due to medical, scientific and socio-economic importance of soft tissue research. Using analytical formulations for specimens under combined inflation/extension/torsion on thick-walled cylindrical tubes, in vitro experiments were carried out with fresh sheep arterial segments, and parameter estimation procedures were carried out on experimental data. Model restrictions were pointed out using outcomes from parameter estimation. Needs for further studies that can be developed are discussed.

  11. Review of the synergies between computational modeling and experimental characterization of materials across length scales

    DOE PAGES

    Dingreville, Rémi; Karnesky, Richard A.; Puel, Guillaume; Schmitt, Jean -Hubert

    2015-11-16

    With the increasing interplay between experimental and computational approaches at multiple length scales, new research directions are emerging in materials science and computational mechanics. Such cooperative interactions find many applications in the development, characterization and design of complex material systems. This manuscript provides a broad and comprehensive overview of recent trends in which predictive modeling capabilities are developed in conjunction with experiments and advanced characterization to gain a greater insight into structure–property relationships and study various physical phenomena and mechanisms. The focus of this review is on the intersections of multiscale materials experiments and modeling relevant to the materials mechanicsmore » community. After a general discussion on the perspective from various communities, the article focuses on the latest experimental and theoretical opportunities. Emphasis is given to the role of experiments in multiscale models, including insights into how computations can be used as discovery tools for materials engineering, rather than to “simply” support experimental work. This is illustrated by examples from several application areas on structural materials. In conclusion this manuscript ends with a discussion on some problems and open scientific questions that are being explored in order to advance this relatively new field of research.« less

  12. Review of the synergies between computational modeling and experimental characterization of materials across length scales

    SciTech Connect

    Dingreville, Rémi; Karnesky, Richard A.; Puel, Guillaume; Schmitt, Jean -Hubert

    2015-11-16

    With the increasing interplay between experimental and computational approaches at multiple length scales, new research directions are emerging in materials science and computational mechanics. Such cooperative interactions find many applications in the development, characterization and design of complex material systems. This manuscript provides a broad and comprehensive overview of recent trends in which predictive modeling capabilities are developed in conjunction with experiments and advanced characterization to gain a greater insight into structure–property relationships and study various physical phenomena and mechanisms. The focus of this review is on the intersections of multiscale materials experiments and modeling relevant to the materials mechanics community. After a general discussion on the perspective from various communities, the article focuses on the latest experimental and theoretical opportunities. Emphasis is given to the role of experiments in multiscale models, including insights into how computations can be used as discovery tools for materials engineering, rather than to “simply” support experimental work. This is illustrated by examples from several application areas on structural materials. In conclusion this manuscript ends with a discussion on some problems and open scientific questions that are being explored in order to advance this relatively new field of research.

  13. 27 CFR 24.249 - Experimentation with new treating material or process.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Experimentation with new treating material or process. 24.249 Section 24.249 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS WINE Storage, Treatment and Finishing...

  14. 27 CFR 24.249 - Experimentation with new treating material or process.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Experimentation with new treating material or process. 24.249 Section 24.249 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS WINE Storage, Treatment and Finishing...

  15. Advanced Experimental Methods for Low-temperature Magnetotransport Measurement of Novel Materials.

    PubMed

    Hagmann, Joseph A; Le, Son T; Richter, Curt A; Seiler, David G

    2016-01-21

    Novel electronic materials are often produced for the first time by synthesis processes that yield bulk crystals (in contrast to single crystal thin film synthesis) for the purpose of exploratory materials research. Certain materials pose a challenge wherein the traditional bulk Hall bar device fabrication method is insufficient to produce a measureable device for sample transport measurement, principally because the single crystal size is too small to attach wire leads to the sample in a Hall bar configuration. This can be, for example, because the first batch of a new material synthesized yields very small single crystals or because flakes of samples of one to very few monolayers are desired. In order to enable rapid characterization of materials that may be carried out in parallel with improvements to their growth methodology, a method of device fabrication for very small samples has been devised to permit the characterization of novel materials as soon as a preliminary batch has been produced. A slight variation of this methodology is applicable to producing devices using exfoliated samples of two-dimensional materials such as graphene, hexagonal boron nitride (hBN), and transition metal dichalcogenides (TMDs), as well as multilayer heterostructures of such materials. Here we present detailed protocols for the experimental device fabrication of fragments and flakes of novel materials with micron-sized dimensions onto substrate and subsequent measurement in a commercial superconducting magnet, dry helium close-cycle cryostat magnetotransport system at temperatures down to 0.300 K and magnetic fields up to 12 T.

  16. The Influence of Root-End Filling Materials on Bone Healing – An Experimental Study

    PubMed Central

    KUI, ANDREEA GULIE; BERAR, ANTONELA; LASCU, LIANA; BOLFA, POMPEI; BOSCA, BIANCA; MIHU, CARMEN; BACIUT, MIHAELA; AVRAM, RAMONA; BADEA, MÂNDRA

    2014-01-01

    Aims. The aim of this experimental study is to assess the bone healing phenomenon produced in the presence of several dental materials: a polycarboxylate cement, a glass-ionomer cement, a composite resin and MTA (mineral trioxide aggregate) based cement. Methods. The biocompatibility of four root-end fillings materials, used in periapical surgery was investigated after intra-osseous implantation of the materials in rats’ calvaria. Tissue reaction was studied at 2, 4, 6, 8, 10 and 12 weeks after implantation. We took into consideration the presence of inflammatory cells (polymorphonuclear leukocytes, macrophages, plasma cells, lymphocytes and giant cells) and classified the aspects of the histological samples according to the following scale: 0 - no inflammation, 1 – mild, isolated inflammation, 2 - moderate, localized inflammatory reaction, 3 - severe, diffuse and intense inflammatory reaction. Results. The inflammatory reaction was present at the six intervals for all the tested materials, but at 12 week interval, the reaction was minimal in all cases. Also, a dissolution reaction was observed for all the materials, less intense for glass-ionomer cement and polycarboxilate cement. Conclusions. At the end of the experimental period, glass-ionomer cement and polycarboxilate cement suffered a lesser dissolution reaction as compared to the second group of tested materials. PMID:26528034

  17. Experimental studies on the performance of novel layered materials under highly dynamic loads

    NASA Astrophysics Data System (ADS)

    Shukla, A.

    2009-08-01

    This paper focuses on the experimental observations of the performance of different layered composite material systems subjected to blast loadings. These material systems include layered composites and sandwich composite materials. A controlled blast loading of pre-defined pressure magnitude and rise time were obtained using a shock tube apparatus. Rectangular plate elements of the desired material system were subjected to such a controlled blast loading and the effects of the blast loading on these elements were studied using optical and residual strength measurements. A high speed imaging technique was utilized to study the damage modes and mechanisms in real time. It was observed that layering of a conventional composite material with a soft visco-elastic polymer provided better blast resistance and sandwiching the polymer greatly enhanced its survivability under extreme air blast conditions. Aside from layering the conventional composite material with a soft visco-elastic polymer, it was observed that layering or grading the core can successfully mitigate the impact damage and thus improve the overall blast resistance as well. In addition to these, three dimensional (3D) woven skin and core reinforcements were introduced in the conventional sandwich composites and their effects on the blast resistance were studied experimentally. It was observed that these reinforcements also enhance the blast resistance of conventional sandwich composites by changing the mechanism of failure initiation and propagation in these sandwich structures.

  18. Experimental flame speed in multi-layered nano-energetic materials

    SciTech Connect

    Manesh, Navid Amini; Basu, Saptarshi; Kumar, Ranganathan

    2010-03-15

    This paper deals with the reaction of dense Metastable Intermolecular Composite (MIC) materials, which have a higher density than conventional energetic materials. The reaction of a multilayer thin film of aluminum and copper oxide has been studied by varying the substrate material and thicknesses. The in-plane speed of propagation of the reaction was experimentally determined using a time of- flight technique. The experiment shows that the reaction is completely quenched for a silicon substrate having an intervening silica layer of less than 200 nm. The speed of reaction seems to be constant at 40 m/s for silica layers with a thickness greater than 1 {mu}m. Different substrate materials such as glass and photoresist were also used. (author)

  19. Experimental study of low amplitude, long-duration mechanical loading of reactive materials

    SciTech Connect

    Urtiew, P A; Forbes, J W

    2000-10-03

    Studies of the low amplitude, long-duration mechanical loading of reactive materials rely very heavily on the experimental data in general and in particular on the data obtained from gauges placed within the experimental test sample to measure accurately the local changes of parameters of the investigated material. For a complete description of these changes taking place in a dynamically loaded material one would like to know both the spatial and the temporal resolution of pressure, temperature, volume, wave and mass velocity. However, temperature and volume are not easily attainable. Therefore, most of the in-situ work is limited to measurements of pressure and both wave and mass velocities. Various types of these gauges will be discussed and their records will be illustrated. Some of these gauges have limitations but are better suited for particular applications than others. These aspects will also be discussed. Main limitation of most in-situ gauges is that they are built for one-dimensional application. However, some work is being done to develop two-dimensional gauges. This work will also be briefly discussed. While these experiments are necessary to validate theoretical models of the phenomenon, they can also provide sufficient amount of data to yield complete information on material characteristics such as its equation of state (EOS), its phase change under certain loads and its sensitivity to shock loading. Processing of these data to get important information on the behavior of both reactive and non-reactive materials will also be demonstrated.

  20. Charging characteristics of materials: Comparison of experimental results with simple analytical models

    NASA Technical Reports Server (NTRS)

    Purvis, C. K.; Stevens, N. J.; Oglebay, J. C.

    1977-01-01

    An understanding of the behavior of materials, of dielectrics in particular, under charged particle bombardment is essential to the prediction and prevention of the adverse effects of spacecraft charging. A one-dimensional model for charging of samples in a test facility was used in conjunction with experimental data taken to develop "material charging characteristics" for silvered Teflon. These characteristics were then used in a one-dimensional model for charging in space to examine expected response. Relative charging rates as well as relative charging levels for silvered Teflon and metal are discussed.

  1. Developing an Experimental Simulation Method for Rock Avalanches: Fragmentation Behavior of Brittle Analogue Material

    NASA Astrophysics Data System (ADS)

    Thordén Haug, Øystein; Rosenau, Matthias; Leever, Karen; Oncken, Onno

    2013-04-01

    Gravitational mass movement on earth and other planets show a scale dependent behavior, of which the physics is not fully understood. In particular, the runout distance for small to medium sized landslides (volume < 106m3) can be predicted by a simple Coulomb friction law consistent with a constant kinetic coefficient of friction at the landslide base. This implies that the runout can be considered independent of volume. Large volume landslides (rock avalanches), however, show a dependence of runout on volume. This break in scaling behavior suggests that different dynamics control small and large landslides/rock avalanches. Several mechanisms have been proposed to explain this scale dependent behavior, but no consensus has been reached. Experimental simulations of rock avalanches usually involve transport of loose granular material down a chute. Though such granular avalanche models provide important insights into avalanche dynamics, they imply that the material fully disintegrate instantaneously. Observations from nature, however, suggests that a transition from solid to "liquid" occurs over some finite distance downhill, critically controlling the mobility and energy budget of the avalanche. Few experimental studies simulated more realistically the material failing during sliding and those were realized in a labscale centrifuge, where the range of volumes/scales is limited. To develop a new modeling technique to study the scale dependent runout behavior of rock avalanches, we designed, tested and verified several brittle materials allowing fragmentation to occur under normal gravity conditions. According to the model similarity theory, the analogue material must behave dynamically similar to the rocks in natural rock avalanches. Ideally, the material should therefore deform in a brittle manner with limited elastic and ductile strains up to a certain critical stress, beyond which the material breaks and deforms irreversibly. According to scaling relations derived

  2. Experimental data showing the thermal behavior of a flat roof with phase change material

    PubMed Central

    Tokuç, Ayça; Başaran, Tahsin; Yesügey, S. Cengiz

    2015-01-01

    The selection and configuration of building materials for optimal energy efficiency in a building require some assumptions and models for the thermal behavior of the utilized materials. Although the models for many materials can be considered acceptable for simulation and calculation purposes, the work for modeling the real time behavior of phase change materials is still under development. The data given in this article shows the thermal behavior of a flat roof element with a phase change material (PCM) layer. The temperature and energy given to and taken from the building element are reported. In addition the solid–liquid behavior of the PCM is tracked through images. The resulting thermal behavior of the phase change material is discussed and simulated in [1] A. Tokuç, T. Başaran, S.C. Yesügey, An experimental and numerical investigation on the use of phase change materials in building elements: the case of a flat roof in Istanbul, Build. Energy, vol. 102, 2015, pp. 91–104. PMID:26629490

  3. Experimental data showing the thermal behavior of a flat roof with phase change material.

    PubMed

    Tokuç, Ayça; Başaran, Tahsin; Yesügey, S Cengiz

    2015-12-01

    The selection and configuration of building materials for optimal energy efficiency in a building require some assumptions and models for the thermal behavior of the utilized materials. Although the models for many materials can be considered acceptable for simulation and calculation purposes, the work for modeling the real time behavior of phase change materials is still under development. The data given in this article shows the thermal behavior of a flat roof element with a phase change material (PCM) layer. The temperature and energy given to and taken from the building element are reported. In addition the solid-liquid behavior of the PCM is tracked through images. The resulting thermal behavior of the phase change material is discussed and simulated in [1] A. Tokuç, T. Başaran, S.C. Yesügey, An experimental and numerical investigation on the use of phase change materials in building elements: the case of a flat roof in Istanbul, Build. Energy, vol. 102, 2015, pp. 91-104.

  4. Experimental data showing the thermal behavior of a flat roof with phase change material.

    PubMed

    Tokuç, Ayça; Başaran, Tahsin; Yesügey, S Cengiz

    2015-12-01

    The selection and configuration of building materials for optimal energy efficiency in a building require some assumptions and models for the thermal behavior of the utilized materials. Although the models for many materials can be considered acceptable for simulation and calculation purposes, the work for modeling the real time behavior of phase change materials is still under development. The data given in this article shows the thermal behavior of a flat roof element with a phase change material (PCM) layer. The temperature and energy given to and taken from the building element are reported. In addition the solid-liquid behavior of the PCM is tracked through images. The resulting thermal behavior of the phase change material is discussed and simulated in [1] A. Tokuç, T. Başaran, S.C. Yesügey, An experimental and numerical investigation on the use of phase change materials in building elements: the case of a flat roof in Istanbul, Build. Energy, vol. 102, 2015, pp. 91-104. PMID:26629490

  5. Melting behavior of typical thermoplastic materials--an experimental and chemical kinetics study.

    PubMed

    Wang, Nan; Tu, Ran; Ma, Xin; Xie, Qiyuan; Jiang, Xi

    2013-11-15

    A medium-scale melting experiment rig was designed and constructed in this study. A detailed experimental study was conducted on the melting behavior and the chemical kinetic characteristics of three typical thermoplastic materials, including polypropylene (PP), polyethylene (PE) and polystyrene (PS). It is observed that the thermal decomposition of the thermoplastic materials mainly consists of three stages: the initial heating stage, the melting-dominated stage and the gasification-dominated stage. Melting of the materials examined takes place within a certain temperature range. The melting temperature of PS is the lowest, moreover, it takes the shortest time to be completely liquefied. To quantitatively represent the chemical kinetics, an nth-order reaction model was employed to interpret the thermal decomposition behavior of the materials. The calculated reaction order is largely in accordance with the small-scale thermal gravimetric analysis (TGA). The small difference between the results and TGA data suggests that there are some limitations in the small-scale experiments in simulating the behavior of thermoplastic materials in a thermal hazard. Therefore, investigating the thermal physical and chemical properties of the thermoplastic materials and their thermal hazard prevention in medium or large-scale experiments is necessary for the fire safety considerations of polymer materials.

  6. Modeling non-harmonic behavior of materials from experimental inelastic neutron scattering and thermal expansion measurements

    DOE PAGES

    Bansal, Dipanshu; Aref, Amjad; Dargush, Gary; Delaire, Olivier A.

    2016-07-20

    Based on thermodynamic principles, we derive expressions quantifying the non-harmonic vibrational behavior of materials, which are rigorous yet easily evaluated from experimentally available data for the thermal expansion coefficient and the phonon density of states. These experimentally-derived quantities are valuable to benchmark first-principles theoretical predictions of harmonic and non-harmonic thermal behaviors using perturbation theory, ab initio molecular-dynamics, or Monte-Carlo simulations. In this study, we illustrate this analysis by computing the harmonic, dilational, and anharmonic contributions to the entropy, internal energy, and free energy of elemental aluminum and the ordered compound FeSi over a wide range of temperature. Our results agreemore » well with previous data in the literature and provide an efficient approach to estimate anharmonic effects in materials.« less

  7. Estimation of moisture transport coefficients in porous materials using experimental drying kinetics

    NASA Astrophysics Data System (ADS)

    Zaknoune, A.; Glouannec, P.; Salagnac, P.

    2012-02-01

    From experimental drying kinetics, an inverse technique is used to evaluate the moisture transport coefficients in building hygroscopic porous materials. Based on the macroscopic approach developed by Whitaker, a one-dimensional mathematical model is developed to predict heat and mass transfers in porous material. The parameters identification is made by the minimisation of the square deviation between numerical and experimental values of the surface temperature and the average moisture content. Two parameters of an exponential function describing the liquid phase transfer and one parameter relative to the diffusion of the vapour phase are identified. To ensure the feasibility of the estimation method, it is initially validated with cellular concrete and applied to lime paste.

  8. Modeling non-harmonic behavior of materials from experimental inelastic neutron scattering and thermal expansion measurements

    NASA Astrophysics Data System (ADS)

    Bansal, Dipanshu; Aref, Amjad; Dargush, Gary; Delaire, Olivier

    2016-09-01

    Based on thermodynamic principles, we derive expressions quantifying the non-harmonic vibrational behavior of materials, which are rigorous yet easily evaluated from experimentally available data for the thermal expansion coefficient and the phonon density of states. These experimentally-derived quantities are valuable to benchmark first-principles theoretical predictions of harmonic and non-harmonic thermal behaviors using perturbation theory, ab initio molecular-dynamics, or Monte-Carlo simulations. We illustrate this analysis by computing the harmonic, dilational, and anharmonic contributions to the entropy, internal energy, and free energy of elemental aluminum and the ordered compound \\text{FeSi} over a wide range of temperature. Results agree well with previous data in the literature and provide an efficient approach to estimate anharmonic effects in materials.

  9. Experimental and analytical investigations of granular materials: Shear flow and convective heat transfer

    NASA Astrophysics Data System (ADS)

    Ahn, Hojin

    1989-12-01

    Granular materials flowing down an inclined chute were studied experimentally and analytically. Characteristics of convective heat transfer to granular flows were also investigated experimentally and numerically. Experiments on continuous, steady flows of granular materials in an inclined chute were conducted with the objectives of understanding the characteristics of chute flows and of acquiring information on the rheological behavior of granular material flow. Existing constitutive equations and governing equations were used to solve for fully developed chute flows of granular materials, and thus the boundary value problem was formulated with two parameters (the coefficient of restitution between particles, and the chute inclination) and three boundary values at the chute base wall (the values of solid fraction, granular temperature, and mean velocity at the wall). The boundary value problem was numerically solved by the shooting method. These analytical results were also compared with the present experimental values and with the computer simulations by other investigators in their literature. Experiments on heat transfer to granular flows over a flat heating plate were conducted with three sizes of glass beads, polystyrene beads, and mustard seeds. A modification on the existing model for the convective heat transfer was made using the effective Nusselt number and the effective Peclet number, which include the effects of solid fraction variations. The slightly modified model could describe the heat transfer characteristics of both fast and slow flows (supercritical and subcritical). A numerical analysis of the transfer to granular flows was also performed. The results were compared with the present experimental data, and reasonable agreement was found in the comparison.

  10. Mathematical modeling and experimental studies on solar energy storage in a phase change material

    SciTech Connect

    Das, S.; Dutta, T.K. )

    1993-11-01

    Solar energy storage in phase change material (PCM) is an effective method. A comprehensive study on a PCM storage system and development of a mathematical model have been attempted in this work in order to describe the melting characteristics of paraffin wax encapsulated in the annulus of two concentric cylinders. The movement of the separation boundary between the solid and molten wax was experimentally determined and compared with theoretical solution.

  11. Optimal experimental designs for the estimation of thermal properties of composite materials

    NASA Technical Reports Server (NTRS)

    Scott, Elaine P.; Moncman, Deborah A.

    1994-01-01

    Reliable estimation of thermal properties is extremely important in the utilization of new advanced materials, such as composite materials. The accuracy of these estimates can be increased if the experiments are designed carefully. The objectives of this study are to design optimal experiments to be used in the prediction of these thermal properties and to then utilize these designs in the development of an estimation procedure to determine the effective thermal properties (thermal conductivity and volumetric heat capacity). The experiments were optimized by choosing experimental parameters that maximize the temperature derivatives with respect to all of the unknown thermal properties. This procedure has the effect of minimizing the confidence intervals of the resulting thermal property estimates. Both one-dimensional and two-dimensional experimental designs were optimized. A heat flux boundary condition is required in both analyses for the simultaneous estimation of the thermal properties. For the one-dimensional experiment, the parameters optimized were the heating time of the applied heat flux, the temperature sensor location, and the experimental time. In addition to these parameters, the optimal location of the heat flux was also determined for the two-dimensional experiments. Utilizing the optimal one-dimensional experiment, the effective thermal conductivity perpendicular to the fibers and the effective volumetric heat capacity were then estimated for an IM7-Bismaleimide composite material. The estimation procedure used is based on the minimization of a least squares function which incorporates both calculated and measured temperatures and allows for the parameters to be estimated simultaneously.

  12. Positron range in tissue-equivalent materials: experimental microPET studies.

    PubMed

    Alva-Sánchez, H; Quintana-Bautista, C; Martínez-Dávalos, A; Ávila-Rodríguez, M A; Rodríguez-Villafuerte, M

    2016-09-01

    In this work an experimental investigation was carried out to study the effect that positron range has over positron emission tomography (PET) scans through measurements of the line spread function (LSF) in tissue-equivalent materials. Line-sources consisted of thin capillary tubes filled with (18)F, (13)N or (68)Ga water-solution inserted along the axis of symmetry of cylindrical phantoms constructed with the tissue-equivalent materials: lung (inhale and exhale), adipose tissue, solid water, trabecular and cortical bone. PET scans were performed with a commercial small-animal PET scanner and image reconstruction was carried out with filtered-backprojection. Line-source distributions were analyzed using radial profiles taken on axial slices from which the spatial resolution was determined through the full-width at half-maximum, tenth-maximum, twentieth-maximum and fiftieth-maximum. A double-Gaussian model of the LSFs was used to fit experimental data which can be incorporated into iterative reconstruction methods. In addition, the maximum activity concentration in the line-sources was determined from reconstructed images and compared to the known values for each case. The experimental data indicates that positron range in different materials has a strong effect on both spatial resolution and activity concentration quantification in PET scans. Consequently, extra care should be taken when computing standard-uptake values in PET scans, in particular when the radiopharmaceutical is taken up by different tissues in the body, and more even so with high-energy positron emitters.

  13. Positron range in tissue-equivalent materials: experimental microPET studies

    NASA Astrophysics Data System (ADS)

    Alva-Sánchez, H.; Quintana-Bautista, C.; Martínez-Dávalos, A.; Ávila-Rodríguez, M. A.; Rodríguez-Villafuerte, M.

    2016-09-01

    In this work an experimental investigation was carried out to study the effect that positron range has over positron emission tomography (PET) scans through measurements of the line spread function (LSF) in tissue-equivalent materials. Line-sources consisted of thin capillary tubes filled with 18F, 13N or 68Ga water-solution inserted along the axis of symmetry of cylindrical phantoms constructed with the tissue-equivalent materials: lung (inhale and exhale), adipose tissue, solid water, trabecular and cortical bone. PET scans were performed with a commercial small-animal PET scanner and image reconstruction was carried out with filtered-backprojection. Line-source distributions were analyzed using radial profiles taken on axial slices from which the spatial resolution was determined through the full-width at half-maximum, tenth-maximum, twentieth-maximum and fiftieth-maximum. A double-Gaussian model of the LSFs was used to fit experimental data which can be incorporated into iterative reconstruction methods. In addition, the maximum activity concentration in the line-sources was determined from reconstructed images and compared to the known values for each case. The experimental data indicates that positron range in different materials has a strong effect on both spatial resolution and activity concentration quantification in PET scans. Consequently, extra care should be taken when computing standard-uptake values in PET scans, in particular when the radiopharmaceutical is taken up by different tissues in the body, and more even so with high-energy positron emitters.

  14. Advanced Experimental Methods for Low-temperature Magnetotransport Measurement of Novel Materials.

    PubMed

    Hagmann, Joseph A; Le, Son T; Richter, Curt A; Seiler, David G

    2016-01-01

    Novel electronic materials are often produced for the first time by synthesis processes that yield bulk crystals (in contrast to single crystal thin film synthesis) for the purpose of exploratory materials research. Certain materials pose a challenge wherein the traditional bulk Hall bar device fabrication method is insufficient to produce a measureable device for sample transport measurement, principally because the single crystal size is too small to attach wire leads to the sample in a Hall bar configuration. This can be, for example, because the first batch of a new material synthesized yields very small single crystals or because flakes of samples of one to very few monolayers are desired. In order to enable rapid characterization of materials that may be carried out in parallel with improvements to their growth methodology, a method of device fabrication for very small samples has been devised to permit the characterization of novel materials as soon as a preliminary batch has been produced. A slight variation of this methodology is applicable to producing devices using exfoliated samples of two-dimensional materials such as graphene, hexagonal boron nitride (hBN), and transition metal dichalcogenides (TMDs), as well as multilayer heterostructures of such materials. Here we present detailed protocols for the experimental device fabrication of fragments and flakes of novel materials with micron-sized dimensions onto substrate and subsequent measurement in a commercial superconducting magnet, dry helium close-cycle cryostat magnetotransport system at temperatures down to 0.300 K and magnetic fields up to 12 T. PMID:26863449

  15. Experimental study of visible and IR light reflection by planetary-like granular materials

    NASA Astrophysics Data System (ADS)

    Douté, S.; Grundy, W.; Devedeux, F.; Schmitt, B.; Brissaud, O.

    2003-04-01

    The exploration of planetary surfaces by spacecrafts now often involves imaging spectroscopy in the visible and near infrared ranges. The development of methods to analyse the generated image cubes requires theoretical as well as experimental studies to model the bidirectional reflectance (BRDF) of dense granular materials. The physics of the reflection depends on many parameters like the intrinsic optical properties, the shapes, sizes and the packing density of the mineral or icy grains forming the top few centimeters of many solid planetary surfaces. The structural characteristics of the transition zone between the materials and the atmosphere or the vacuum may also play a key role. In particular surface roughness at the scale of tens of grain lengths and facets preferentially oriented in the horizontal plane may greatly determine the BRDF. In this paper, we present the results of a systematic experimental campaign designed to quantify the dependence of the BRDF on the crucial parameters mentioned above. For that purpose we measured, with a spectrophoto-goniometer, the BRDF of various test granular materials (paraffin, glass fragments, epsomite or sodium fluoride, etc.) at several wavelengths. These materials present an increasing optical index from 1.32 to 3.4 and sometimes show isolated absorption bands. They come in various grain sizes and shapes and were prepared using different methods to make samples with different surface textures.

  16. Negative refraction and energy funneling by hyperbolic materials: an experimental demonstration in acoustics.

    PubMed

    García-Chocano, Victor M; Christensen, Johan; Sánchez-Dehesa, José

    2014-04-11

    This Letter reports the design, fabrication, and experimental characterization of hyperbolic materials showing negative refraction and energy funneling of airborne sound. Negative refraction is demonstrated using a stack of five holey Plexiglas plates where their thicknesses, layer separation, hole diameters, and lattice periodicity have been determined to show hyperbolic dispersion around 40 kHz. The resulting hyperbolic material shows a flat band profile in the equifrequency contour allowing the gathering of acoustic energy in a broad range of incident angles and its funneling through the material. Our demonstrations foresee interesting developments based on both phenomena. Acoustic imaging with subwavelength resolution and spot-size converters that harvest and squeeze sound waves irradiating from many directions into a collimated beam are just two possible applications among many.

  17. Hazards Response of Energetic Materials - Initiation Mechanisms, Experimental Characterization, and Development of Predictive Capability

    SciTech Connect

    Maienschein, J; Nichols III, A; Reaugh, J; McClelland, M; Hsu, P C

    2005-04-15

    We present our approach to develop a predictive capability for hazards -- thermal and non-shock impact -- response of energetic material systems based on: (A) identification of relevant processes; (B) characterization of the relevant properties; (C) application of property data to predictive models; and (D) application of the models into predictive simulation. This paper focuses on the first two elements above, while a companion paper by Nichols et al focuses on the final two elements. We outline the underlying mechanisms of hazards response and their interactions, and present our experimental work to characterize the necessary material parameters, including thermal ignition, thermal and mechanical properties, fracture/fragmentation behavior, deflagration rates, and the effect of material damage. We also describe our validation test, the Scaled Thermal Explosion Experiment. Finally, we integrate the entire collection of data into a qualitative understanding that is useful until such time as the predictive models become available.

  18. Standardization of the carbon-phenolic materials and processes. Vol. 1: Experimental studies

    NASA Technical Reports Server (NTRS)

    Hall, William B.

    1988-01-01

    Carbon-phenolic composite materials are used as ablative material in the solid rocket motor nozzle of the Space Shuttle. The nozzle is lined with carbon cloth-phenolic resin composites. The nominal effects of the completely consumed solid propellant on the carbon-phenolic material are given. The extreme heat and erosion of the burning propellant are controlled by the carbon-phenolic composite by ablation, the heat and mass transfer process in which a large amount of heat is absorbed by sacrificially removing material from the nozzle surface. Phenolic materials ablate with the initial formation of a char. The depth of the char is a function of the heat conduction coefficient of the composite. The char layer is a very poor heat conductor so it protects the underlying phenolic composite from the high heat of the burning propellant. The nozzle component ablative liners (carbon cloth-phenolic composites) are tape wrapped, hydroclave and/or autoclave cured, machined, and assembled. The tape consists of a prepreg broadcloth. The materials flow sheet for the nozzle ablative liners is shown. The prepreg is a three component system: phenolic resin, carbon cloth, and carbon filler. This is Volume 1 of two, Experimental Studies.

  19. A new experimental material for modeling relief dynamics and interactions between tectonics and surface processes

    NASA Astrophysics Data System (ADS)

    Graveleau, F.; Hurtrez, J.-E.; Dominguez, S.; Malavieille, J.

    2011-12-01

    We developed a new granular material (MatIV) to study experimentally landscape evolution in active mountain belt piedmonts. Its composition and related physical properties have been determined using empirical criteria derived from the scaling of deformation, erosion-transport and sedimentation natural processes. MatIV is a water-saturated composite material made up with 4 granular components (silica powder, glass microbeads, plastic powder and graphite) whose physical, mechanical and erosion-related properties were measured with different laboratory tests. Mechanical measurements were made on a modified Hubbert-type direct shear apparatus. Erosion-related properties were determined using an experimental set-up that allows quantifying the erosion/sedimentation budget from tilted relaxation topographies. For MatIV, we also investigated the evolution of mean erosion rates and stream power erosion law exponents in 1D as a function of slope. Our results indicate that MatIV satisfies most of the defined criteria. It deforms brittlely according to the linear Mohr-Coulomb failure criterion and localizes deformation along discrete faults. Its erosion pattern is characterized by realistic hillslope and channelized processes (slope diffusion, mass wasting, channel incision). During transport, eroded particles are sorted depending on their density and shape, which results in stratified alluvial deposits displaying lateral facies variations. To evaluate the degree of similitude between model and nature, we used a new experimental device that combines accretionary wedge deformation mechanisms and surface runoff erosion processes. Results indicate that MatIV succeeded in producing detailed morphological and sedimentological features (drainage basin, channel network, terrace, syntectonic alluvial fan). Geometric, kinematic and dynamic similarity criteria have been investigated to compare precisely model to nature. Although scaling is incomplete, it yields particularly informative

  20. Plant growth response in experimental soilless mixes prepared from coal combustion products and organic waste materials

    SciTech Connect

    Bardhan, S.; Watson, M.; Dick, W.A.

    2008-07-15

    Large quantities of organic materials such as animal manures, yard trimmings, and biosolids are produced each year. Beneficial use options for them are often limited, and composting has been proposed as a way to better manage these organic materials. Similarly, burning of coal created 125 million tons of coal combustion products (CCP) in the United States in 2006. An estimated 53 million tons of CCP were reused, whereas the remainder was deposited in landfills. By combining CCP and composted organic materials (COM), we were able to create soilless plant growth mixes with physicochemical conditions that can support excellent plant growth. An additional benefit is the conservation of natural raw materials, such as peat, which is generally used for making soilless mixes. Experimental mixes were formulated by combining CCP and COM at ratios ranging from 2:8 to 8:2 (vol/vol), respectively. Water content at saturation for the created mixes was 63% to 72%, whereas for the commercial control, it was 77%. pH values for the best performing mixes ranged between 5.9 and 6.8. Electrical conductivity and concentrations of required plant nutrient were also within plant growth recommendations for container media. Significantly (P < 0.0001) higher plant biomass growth (7%-130%) was observed in the experimental mixes compared with a commercial mix. No additional fertilizers were provided during the experiment, and reduced fertilization costs can thus accrue as an added benefit to the grower. In summary, combining CCP and COM, derived from source materials often viewed as wastes, can create highly productive plant growth mixes.

  1. Theoretical and experimental investigation of acoustic streaming in a porous material.

    PubMed

    Poesio, Pietro; Ooms, Gijs; Schraven, Arthur; van der Bas, Fred

    2002-07-01

    An experimental and theoretical investigation of the influence of high-frequency acoustic waves on the flow of a liquid through a porous material has been made. Particular attention was paid to the phenomenon of acoustic streaming of the liquid in the porous material due to the damping of the acoustic waves. The experiments were performed on Berea sandstone cores. Two acoustic horns were used with frequencies of 20 and 40 kHz, and with maximum power output of 2 and 0.7 kW, respectively. A high external pressure was applied in order to avoid cavitation. A microphone was used to measure the damping of the waves in the porous material and also temperature and pressure measurements in the flowing liquid inside the cores were carried out. To model the acoustic streaming effect Darcy's law was extended with a source term representing the momentum transfer from the acoustic waves to the liquid. The model predictions for the pressure distribution inside the core under acoustic streaming conditions are in reasonable agreement with the experimental data.

  2. Hybrid hierarchical bio-based materials: Development and characterization through experimentation and computational simulations

    NASA Astrophysics Data System (ADS)

    Haq, Mahmoodul

    Environmentally friendly bio-based composites with improved properties can be obtained by harnessing the synergy offered by hybrid constituents such as multiscale (nano- and micro-scale) reinforcement in bio-based resins composed of blends of synthetic and natural resins. Bio-based composites have recently gained much attention due to their low cost, environmental appeal and their potential to compete with synthetic composites. The advantage of multiscale reinforcement is that it offers synergy at various length scales, and when combined with bio-based resins provide stiffness-toughness balance, improved thermal and barrier properties, and increased environmental appeal to the resulting composites. Moreover, these hybrid materials are tailorable in performance and in environmental impact. While the use of different concepts of multiscale reinforcement has been studied for synthetic composites, the study of mukiphase/multiscale reinforcements for developing new types of sustainable materials is limited. The research summarized in this dissertation focused on development of multiscale reinforced bio-based composites and the effort to understand and exploit the synergy of its constituents through experimental characterization and computational simulations. Bio-based composites consisting of petroleum-based resin (unsaturated polyester), natural or bio-resin (epoxidized soybean and linseed oils), natural fibers (industrial hemp), and nanosilicate (nanoclay) inclusions were developed. The work followed the "materials by Mahmoodul Haq design" philosophy by incorporating an integrated experimental and computational approach to strategically explore the design possibilities and limits. Experiments demonstrated that the drawbacks of bio-resin addition, which lowers stiffness, strength and increases permeability, can be counter-balanced through nanoclay reinforcement. Bio-resin addition yields benefits in impact strength and ductility. Conversely, nanoclay enhances stiffness

  3. Experimental validation of systematically designed acoustic hyperbolic meta material slab exhibiting negative refraction

    NASA Astrophysics Data System (ADS)

    Christiansen, Rasmus E.; Sigmund, Ole

    2016-09-01

    This Letter reports on the experimental validation of a two-dimensional acoustic hyperbolic metamaterial slab optimized to exhibit negative refractive behavior. The slab was designed using a topology optimization based systematic design method allowing for tailoring the refractive behavior. The experimental results confirm the predicted refractive capability as well as the predicted transmission at an interface. The study simultaneously provides an estimate of the attenuation inside the slab stemming from the boundary layer effects—insight which can be utilized in the further design of the metamaterial slabs. The capability of tailoring the refractive behavior opens possibilities for different applications. For instance, a slab exhibiting zero refraction across a wide angular range is capable of funneling acoustic energy through it, while a material exhibiting the negative refractive behavior across a wide angular range provides lensing and collimating capabilities.

  4. Experimental observations of root growth in a controlled photoelastic granular material

    NASA Astrophysics Data System (ADS)

    Mora, Serge; Bares, Jonathan; Delenne, Jean-Yves; Fourcaud, Thierry

    The mechanism of root growth in soil is a key issue to understand both how to improve plant development and how to stabilize grounds. However, no experimental studies have been carried out to directly observe root development and surrounding stress while imposing specific grain configurations or mechanical loading. We present a novel set-up which permits to observe the development of chickpea root networks in a 2D granular material made of bidisperse photoelastic discs while imposing the position of the grains, the intergranular spacing and the nature of the system confinement: (i) open cell, (ii) confined cell (iii) sheared cell. In the experimental apparatus several root development cells are treated in parallel to increase the statistical meaning of the observations. Evolution of the root network is followed as well as position and pressure inside each disc by mean of a camera and classical photoelastic techniques. Preliminary results will be presented.

  5. Development of intermediate and high strain rate experimentation and material modeling for viscoplastic metals

    NASA Astrophysics Data System (ADS)

    Whittington, Wilburn Ray

    This work presents a combined theoretical-experimental study of strain rate behavior in metals. The method is to experimentally calibrate and validate an Internal State Variable (ISV) constitutive model with a wide range of strain rate sensitivity. Therefore a practical apparatus and methodology for performing highly sought-after intermediate strain rate experimentation was created. For the first time in reported literature, the structure-property relations of Rolled Homogeneous Armor is quantified at the microscale and modeled with varying strain rates, temperatures, and stress states to capture plasticity and damage with a single set of constants that includes intermediate strain rates. A rolled homogeneous armor (RHA) was used as a material system to prove the methodology. In doing so, a newly implemented strain rate dependent nucleation parameter for RHA was implemented to transition the dominant damage mechanism from void growth to void nucleation as strain rate increased. The ISVs were utilized in finite element analysis for robust predictability of mechanical performance as well as predictability of microstructural evolution with regards to void size and number distribution. For intermediate strain rate experiments, robust load acquisition was achieved using a novel serpentine transmittal bar that allowed for long stress waves to traverse a short bar system; this system eliminated load- ringing that plagues servo-hydraulic systems. A direct hydraulic loading apparatus was developed to provide uniform strain rates throughout intermediate rate tests to improve on the current limitations of the state-of-the-art. Key recommendations on the advancement of predictive modeling of dynamic materials, as well as performing advanced dynamic experimentation, are elucidated.

  6. Highly porous thermal protection materials: Modelling and prediction of the methodical experimental errors

    NASA Astrophysics Data System (ADS)

    Cherepanov, Valery V.; Alifanov, Oleg M.; Morzhukhina, Alena V.; Budnik, Sergey A.

    2016-11-01

    The formation mechanisms and the main factors affecting the systematic error of thermocouples were investigated. According to the results of experimental studies and mathematical modelling it was established that in highly porous heat resistant materials for aerospace application the thermocouple errors are determined by two competing mechanisms provided correlation between the errors and the difference between radiation and conduction heat fluxes. The comparative analysis was carried out and some features of the methodical error formation related to the distances from the heated surface were established.

  7. Experimental investigation of solid by-product as sensible heat storage material: Characterization and corrosion study

    NASA Astrophysics Data System (ADS)

    Ortega-Fernández, Iñigo; Faik, Abdessamad; Mani, Karthik; Rodriguez-Aseguinolaza, Javier; D'Aguanno, Bruno

    2016-05-01

    The experimental investigation of water cooled electrical arc furnace (EAF) slag used as filler material in the storage tank for sensible heat storage application was demonstrated in this study. The physicochemical and thermal properties of the tested slags were characterized by using X-ray diffraction, scanning electron microcopy, Fourier transform infrared spectroscopy, Raman spectroscopy and laser flash analysis, respectively. In addition, the chemical compatibility between slags and molten nitrate salt (60 wt. % NaNO3 and 40 wt. % KNO3) was investigated at 565 °C for 500 hrs. The obtained results were clearly demonstrated that the slags showed a good corrosion resistance in direct contact with molten salt at elevated temperature. The present study was clearly indicated that a low-cost filler material used in the storage tank can significantly reduce the overall required quantities of the relatively higher cost molten salt and consequently reduce the overall cost of the electricity production.

  8. Toward new fuel cell support materials: a theoretical and experimental study of nitrogen-doped graphene.

    PubMed

    Seo, Min Ho; Choi, Sung Mook; Lim, Eun Ja; Kwon, In Hye; Seo, Joon Kyo; Noh, Seung Hyo; Kim, Won Bae; Han, Byungchan

    2014-09-01

    Nano-scale Pt particles are often reported to be more electrochemically active and stable in a fuel cell if properly displaced on support materials; however, the factors that affect their activity and stability are not well understood. We applied first-principles calculations and experimental measurements to well-defined model systems of N-doped graphene supports (N-GNS) to reveal the fundamental mechanisms that control the catalytic properties and structural integrity of nano-scale Pt particles. DFT calculations predict thermodynamic and electrochemical interactions between N-GNS and Pt nanoparticles in the methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR). Moreover, the dissolution potentials of the Pt nanoparticles supported on GNS and N-GNS catalysts are calculated under acidic conditions. Our results provide insight into the design of new support materials for enhanced catalytic efficiency and long-term stability.

  9. Experimental studies in fluid mechanics and materials science using acoustic levitation

    NASA Technical Reports Server (NTRS)

    Trinh, E. H.; Robey, J.; Arce, A.; Gaspar, M.

    1987-01-01

    Ground-based and short-duration low gravity experiments have been carried out with the use of ultrasonic levitators to study the dynamics of freely suspended liquid drops under the influence of predominantly capillary and acoustic radiation forces. Some of the effects of the levitating field on the shape as well as the fluid flow fields within the drop have been determined. The development and refinement of measurement techniques using levitated drops with size on the order of 2 mm in diameter have yielded methods having direct application to experiments in microgravity. In addition, containerless melting, undercooling, and freezing of organic materials as well as low melting metals have provided experimental data and observations on the application of acoustic positioning techniques to materials studies.

  10. Using experimental design modules for process characterization in manufacturing/materials processes laboratories

    NASA Technical Reports Server (NTRS)

    Ankenman, Bruce; Ermer, Donald; Clum, James A.

    1994-01-01

    Modules dealing with statistical experimental design (SED), process modeling and improvement, and response surface methods have been developed and tested in two laboratory courses. One course was a manufacturing processes course in Mechanical Engineering and the other course was a materials processing course in Materials Science and Engineering. Each module is used as an 'experiment' in the course with the intent that subsequent course experiments will use SED methods for analysis and interpretation of data. Evaluation of the modules' effectiveness has been done by both survey questionnaires and inclusion of the module methodology in course examination questions. Results of the evaluation have been very positive. Those evaluation results and details of the modules' content and implementation are presented. The modules represent an important component for updating laboratory instruction and to provide training in quality for improved engineering practice.

  11. Experimental study of ice lens formation using fine granular materials under terrestrial and martian conditions

    NASA Astrophysics Data System (ADS)

    Saruya, T.; Rempel, A. W.; Kurita, K.

    2012-12-01

    Detailed exploration of Mars has yielded a range of direct and indirect evidence for the distribution of ice. Significantly, direct observations of segregated ice (i.e. sediment free) were obtained by Phoenix lander. This segregated ice most likely originated as an ice lens, which formed by the migration and solidification of unfrozen water. Unfrozen water that is adsorbed to particle surfaces and confined to capillary regions remains in the liquid state below the normal melting temperature. This water is known to migrate in frozen materials and form ice lenses. Zent et al. (2012) developed a numerical model for ice lens formation (Rempel et al. 2004) and demonstrated that the nucleation of ice lenses at the Phoenix landing site was possible in the recent past. However, many questions remain regarding the detailed conditions of ice lens nucleation and growth, even in the terrestrial environment. Further experimental checks of numerical models are especially needed. Here, we describe laboratory investigations of ice lens behavior under both terrestrial conditions and with experimental conditions approaching those in the martian environment. We have performed a series of step-freezing experiments in fine, granular materials to observe the initiation and growth of ice lenses. Our experiments reveal clear and systematic relationships between ice-lens behavior and the imposed cooling temperature and host particle size. We compared our experimental results to numerical predictions from a model of ice lens formation (Rempel et al. 2004) that was applied to our experimental conditions. We find that the trend is consistent between the experiment and model, however, there are important quantitative differences. Most notably, modeled ice-lens nucleation occurred more quickly and enabled ice lenses to grow larger than occurred during our experiments. We infer that some additional mechanisms must be responsible for restricting the formation and growth of ice lenses. Further

  12. Novel nano-particles as fillers for an experimental resin-based restorative material.

    PubMed

    Rüttermann, S; Wandrey, C; Raab, W H-M; Janda, R

    2008-11-01

    The purpose of this study is to compare the properties of two experimental materials, nano-material (Nano) and Microhybrid, and two trade products, Clearfil AP-X and Filtek Supreme XT. The flexural strength and modulus after 24h water storage and 5000 thermocycles, water sorption, solubility and X-ray opacity were determined according to ISO 4049. The volumetric behavior (DeltaV) after curing and after water storage was investigated with the Archimedes principle. ANOVA was calculated with p<0.05. Clearfil AP-X showed the highest flexural strength (154+/-14 MPa) and flexural modulus (11,600+/-550 MPa) prior to and after thermocycling (117+/-14 MPa and 13,000+/-300 MPa). The flexural strength of all materials decreased after thermocycling, but the flexural modulus decreased only for Filtek Supreme XT. After thermocycling, there were no significant differences in flexural strength and modulus between Filtek Supreme XT, Microhybrid and Nano. Clearfil AP-X had the lowest water sorption (22+/-1.1 microg mm(-3)) and Nano had the highest water sorption (82+/-2.6 microg mm(-3)) and solubility (27+/-2.9 microg mm(-3)) of all the materials. No significant differences occurred between the solubility of Clearfil AP-X, Filtek Supreme XT and Microhybrid. Microhybrid and Nano provided the highest X-ray opacity. Owing to the lower filler content, Nano showed higher shrinkage than the commercial materials. Nano had the highest expansion after water storage. After thermocycling, Nano performed as well as Filtek Supreme XT for flexural strength, even better for X-ray opacity but significantly worse for flexural modulus, water sorption and solubility. The performances of microhybrids were superior to those of the nano-materials. PMID:18635411

  13. Novel nano-particles as fillers for an experimental resin-based restorative material.

    PubMed

    Rüttermann, S; Wandrey, C; Raab, W H-M; Janda, R

    2008-11-01

    The purpose of this study is to compare the properties of two experimental materials, nano-material (Nano) and Microhybrid, and two trade products, Clearfil AP-X and Filtek Supreme XT. The flexural strength and modulus after 24h water storage and 5000 thermocycles, water sorption, solubility and X-ray opacity were determined according to ISO 4049. The volumetric behavior (DeltaV) after curing and after water storage was investigated with the Archimedes principle. ANOVA was calculated with p<0.05. Clearfil AP-X showed the highest flexural strength (154+/-14 MPa) and flexural modulus (11,600+/-550 MPa) prior to and after thermocycling (117+/-14 MPa and 13,000+/-300 MPa). The flexural strength of all materials decreased after thermocycling, but the flexural modulus decreased only for Filtek Supreme XT. After thermocycling, there were no significant differences in flexural strength and modulus between Filtek Supreme XT, Microhybrid and Nano. Clearfil AP-X had the lowest water sorption (22+/-1.1 microg mm(-3)) and Nano had the highest water sorption (82+/-2.6 microg mm(-3)) and solubility (27+/-2.9 microg mm(-3)) of all the materials. No significant differences occurred between the solubility of Clearfil AP-X, Filtek Supreme XT and Microhybrid. Microhybrid and Nano provided the highest X-ray opacity. Owing to the lower filler content, Nano showed higher shrinkage than the commercial materials. Nano had the highest expansion after water storage. After thermocycling, Nano performed as well as Filtek Supreme XT for flexural strength, even better for X-ray opacity but significantly worse for flexural modulus, water sorption and solubility. The performances of microhybrids were superior to those of the nano-materials.

  14. Experimental study of bentonite-soil mixtures as anti-seepage materials of constructed wetlands.

    PubMed

    Chen, Jing; Li, Zifu; Zhao, Xin; Li, Haihan

    2011-01-01

    In this study, mixtures of different kinds of bentonite and soil were used and tested in order to find a cheap alternative to current anti-seepage materials for constructed wetlands. The anti-seepage layer of constructed wetlands was simulated in the experimental study and the permeability coefficient of the mixed materials was determined in order to evaluate the anti-seepage effect of mixtures. The main results are as follows: (i) The minimum mass ratio of bentonite to soil is 10%; (ii) Within a certain range, the more compact and higher the wet density is, then the better anti-seepage effect is (under the condition of certain moisture content). The permeability coefficient of the mixed materials exponentially increased with the increase of wet density; (iii) At the wet density of 1.83 g/cm(3), corresponding with the optimum compactness, the mixture of natural sodium bentonite produced in Wyoming, USA and soil from Cangzhou, Hebei province showed the best anti-seepage performance; (iv) The impermeability of the mixture with smaller particle sizes of bentonite was far better than that with the bigger particle sizes; (v) The hydration effect of bentonite changed the structure of the mixture materials into a special structure that is similar to that of pure bentonite. The particles of the mixture became expanded under SEM investigation and the mixture became more compact, which could have the same or similar effect as pure bentonite for anti-seepage.

  15. Study on clogging mechanism of fibrous materials in a pump by experimental and computational approaches

    NASA Astrophysics Data System (ADS)

    Kudo, H.; Kawahara, T.; Kanai, H.; Miyagawa, K.; Saito, S.; Isono, M.; Nohmi, M.; Uchida, H.; Kawai, M.

    2014-03-01

    Clogging trouble in a sewage pump is a serious problem caused by foreign substances like strings, towels, and cloths. However, mechanism of pump clogging is significantly complicated and it is difficult to clarify factors affecting pump clogging. In this paper, the simplified air duct test and axial fan test are introduced and some parameter studies based on design of experiments (DOE) were conducted. From the DOE results, the sensitivity of each parameter to the clogging was predicted. As the parameters related to the clogging, length and rigidity of the strings, leading shape and lean angle of obstacles, flow velocity in a measuring section were selected. Behavior of string in the pump was also observed in the actual pump apparatus and was compared to that in the air duct. Computational simulation with simplified flow fields and MBD (Multi Body Dynamics) was developed and applied to predict behavior of a string in the pump. These experiments and computation are effective to detect and classify the clogging mechanism. These approaches aided to establish one of the evaluation methods on anti-clogging performance against fibrous materials.

  16. Thermal management of Li-ion battery with phase change material for electric scooters: experimental validation

    NASA Astrophysics Data System (ADS)

    Khateeb, Siddique A.; Amiruddin, Shabab; Farid, Mohammed; Selman, J. Robert; Al-Hallaj, Said

    This work reports the laboratory test results of a Li-ion battery designed for electric scooter applications. Four different modes of heat dissipation were investigated in this experimental study: (1) natural convection cooling; (2) presence of aluminum foam heat transfer matrix; (3) use of phase change material (PCM); and (4) combination of aluminum foam and PCM. The objective of using the PCM is to lower the temperature rise of the Li-ion cells and create a uniform temperature distribution in the battery module. This is clearly justified looking at the experimental results presented in this work. The use of high thermal conductivity aluminum foam in the voids between the cells reduces the temperature rise of the Li-ion cells but is insufficient when operated in high ambient temperature such as those usually occur in summer. The use of aluminum foam with PCM causes a significant temperature drop of about 50% compared to the first case of no thermal management. It also provides uniform temperature distribution within the battery module, which is important for the efficient performance of the cells used. The laboratory results were modeled using a 2-D thermal model accounting for the four different modes of heat dissipation and good agreement was obtained between the simulation and experimental results.

  17. Modeling, simulation and experimental verification of constitutive models for energetic materials

    SciTech Connect

    Haberman, K.S.; Bennett, J.G.; Assay, B.W.

    1997-09-01

    Simulation of the complete response of components and systems composed of energetic materials, such as PBX-9501 is important in the determination of the safety of various explosive systems. For example, predicting the correct state of stress, rate of deformation and temperature during penetration is essential in the prediction of ignition. Such simulation requires accurate constitutive models. These models must also be computationally efficient to enable analysis of large scale three dimensional problems using explicit lagrangian finite element codes such as DYNA3D. However, to be of maximum utility, these predictions must be validated against robust dynamic experiments. In this paper, the authors report comparisons between experimental and predicted displacement fields in PBX-9501 during dynamic deformation, and describe the modeling approach. The predictions used Visco-SCRAM and the Generalized Method of Cells which have been implemented into DYNA3D. The experimental data were obtained using laser-induced fluorescence speckle photography. Results from this study have lead to more accurate models and have also guided further experimental work.

  18. Experimental Characterization and Material-Model Development for Microphase-Segregated Polyurea: An Overview

    NASA Astrophysics Data System (ADS)

    Grujicic, M.; He, T.; Pandurangan, B.; Svingala, F. R.; Settles, G. S.; Hargather, M. J.

    2012-01-01

    Numerous experimental investigations reported in the open literature over the past decade have clearly demonstrated that the use of polyurea external coatings and/or inner layers can substantially enhance both the blast resistance (the ability to withstand shock loading) and the ballistic performance (the ability to defeat various high-velocity projectiles such as bullets, fragments, shrapnel, etc. without penetration, excessive deflection or spalling) of buildings, vehicles, combat-helmets, etc. It is also well established that the observed high-performance of polyurea is closely related to its highly complex submicron scale phase-segregated microstructure and the associated microscale phenomena and processes (e.g., viscous energy dissipation at the internal phase boundaries). As higher and higher demands are placed on blast/ballistic survivability of the foregoing structures, a need for the use of the appropriate transient nonlinear dynamics computational analyses and the corresponding design-optimization methods has become ever apparent. A critical aspect of the tools used in these analyses and methods is the availability of an appropriate physically based, high-fidelity material model for polyurea. There are presently several public domain and highly diverse material models for polyurea. In the present work, an attempt is made to critically assess these models as well as the experimental methods and results used in the process of their formulation. Since these models are developed for use in the high-rate loading regime, they are employed in the present work, to generate the appropriate shock-Hugoniot relations. These relations are subsequently compared with their experimental counterparts in order to assess the fidelity of these models.

  19. Optimum iodine concentration of contrast material through microcatheters: hydrodynamic analysis of experimental results.

    PubMed

    Yamauchi, Teiyu; Furui, Shigeru; Harasawa, Arimi; Ishimura, Makoto; Imai, Tatsuhiko; Hayashi, Toshimitsu

    2002-07-21

    It is important to increase the iodine delivery rate (I), that is the iodine concentration of the contrast material (C) x the flow rate of the contrast material (Q), through a catheter to obtain high quality arteriograms. The iodine delivery rate varies depending on the iodine concentration of the contrast material. The purpose of this study is to estimate the optimum iodine concentration (Copt) of contrast material (i.e. the iodine concentration at which I becomes maximum) through a microcatheter of a given length (L), inner diameter (D) and injection pressure (P). Iohexol, ioversol and iopamidol of 11-12 iodine concentrations (140-350, 160-350 or 160-370 mg cm(-3)) at 37 degrees C are used. I and Reynolds number (Re) of the flow of each contrast material through four microcatheters (0.49-0.68 mm in inner diameter, 1000-1500 mm in length) at injection pressures of 1.38, 2.76, 4.14 and 5.52 x 10(6) Pa (200, 400, 600 and 800 pounds per square inch) are obtained experimentally. The relationships between I and C and between I and Re are examined for each catheter and injection pressure. Copt is 160-280 mg cm(-3) for iohexol, 180-280 mg cm(-3) for ioversol and 200-300 mg cm(-3) for iopamidol. I becomes maximum when Re approximates the critical Reynolds number (Re approximately 2300). Utilizing this principle, we can estimate Copt and its flow rate through a microcatheter of a given L, D and P.

  20. Experimental Investigation of Material Flows Within FSWs Using 3D Tomography

    SciTech Connect

    Charles R. Tolle; Timothy A. White; Karen S. Miller; Denis E. Clark; Herschel B. Smartt

    2008-06-01

    There exists significant prior work using tracers or pre-placed hardened markers within friction stir welding (FSWing) to experimentally explore material flow within the FSW process. Our experiments replaced markers with a thin sheet of copper foil placed between the 6061 aluminum lap and butt joints that were then welded. The absorption characteristics of x-rays for copper and aluminum are significantly different allowing for non-destructive evaluation (NDE) methods such as x-ray computed tomography (CT) to be used to demonstrate the material movement within the weldment on a much larger scale than previously shown. 3D CT reconstruction of the copper components of the weldment allows for a unique view into the final turbulent state of the welding process as process parameters are varied. The x-ray CT data of a section of the weld region was collected using a cone-beam x-ray imaging system developed at the INL. Six-hundred projections were collected over 360-degrees using a 160-kVp Bremsstrahlung x-ray generator (25-micrometer focal spot) and amorphoussilicon x-ray detector. The region of the object that was imaged was about 3cm tall and 1.5cm x 1cm in cross section, and was imaged at a magnification of about 3.6x. The data were reconstructed on a 0.5x0.5x0.5 mm3 voxel grid. After reconstruction, the aluminum and copper could be easily discriminated using a gray level threshold allowing visualization of the copper components. Fractal analysis of the tomographic reconstructed material topology is investigated as a means to quantify macro level material flow based on process parameters. The results of multi-pass FSWs show increased refinement of the copper trace material. Implications of these techniques for quantifying process flow are discussed.

  1. Optimum iodine concentration of contrast material through microcatheters: hydrodynamic analysis of experimental results

    NASA Astrophysics Data System (ADS)

    Yamauchi, Teiyu; Furui, Shigeru; Harasawa, Arimi; Ishimura, Makoto; Imai, Tatsuhiko; Hayashi, Toshimitsu

    2002-07-01

    It is important to increase the iodine delivery rate (I), that is the iodine concentration of the contrast material (C) × the flow rate of the contrast material (Q), through a catheter to obtain high quality arteriograms. The iodine delivery rate varies depending on the iodine concentration of the contrast material. The purpose of this study is to estimate the optimum iodine concentration (Copt) of contrast material (i.e. the iodine concentration at which I becomes maximum) through a microcatheter of a given length (L), inner diameter (D) and injection pressure (P). Iohexol, ioversol and iopamidol of 11-12 iodine concentrations (140-350, 160-350 or 160-370 mg cm-3) at 37 °C are used. I and Reynolds number (Re) of the flow of each contrast material through four microcatheters (0.49-0.68 mm in inner diameter, 1000-1500 mm in length) at injection pressures of 1.38, 2.76, 4.14 and 5.52 × 106 Pa (200, 400, 600 and 800 pounds per square inch) are obtained experimentally. The relationships between I and C and between I and Re are examined for each catheter and injection pressure. Copt is 160-280 mg cm-3 for iohexol, 180-280 mg cm-3 for ioversol and 200-300 mg cm-3 for iopamidol. I becomes maximum when Re approximates the critical Reynolds number (Re ≃ 2300). Utilizing this principle, we can estimate Copt and its flow rate through a microcatheter of a given L, D and P.

  2. Importance of the gas phase role to the prediction of energetic material behavior: An experimental study

    SciTech Connect

    Ali, A.N.; Son, S.F.; Asay, B.W.; Sander, R.K.

    2005-03-15

    Various thermal (radiative, conductive, and convective) initiation experiments are performed to demonstrate the importance of the gas phase role in combustion modeling of energetic materials (EM). A previously published condensed phase model that includes a predicted critical irradiance above which ignition is not possible is compared to experimental laser ignition results for octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and 2,4,6-trinitrotoluene (TNT). Experimental results conflict with the predicted critical irradiance concept. The failure of the model is believed to result from a misconception about the role of the gas phase in the ignition process of energetic materials. The model assumes that ignition occurs at the surface and that evolution of gases inhibits ignition. High speed video of laser ignition, oven cook-off and hot wire ignition experiments captures the ignition of HMX and TNT in the gas phase. A laser ignition gap test is performed to further evaluate the effect of gas phase laser absorption and gas phase disruption on the ignition process. Results indicate that gas phase absorption of the laser energy is probably not the primary factor governing the gas phase ignition observations. It is discovered that a critical gap between an HMX pellet and a salt window of 6 mm{+-}0.4 mm exists below which ignition by CO{sub 2} laser is not possible at the tested irradiances of 29 W/cm{sup 2} and 38 W/cm{sup 2} for HMX ignition. These observations demonstrate that a significant disruption of the gas phase, in certain scenarios, will inhibit ignition, independent of any condensed phase processes. These results underscore the importance of gas phase processes and illustrate that conditions can exist where simple condensed phase models are inadequate to accurately predict the behavior of energetic materials.

  3. First principle computational and experimental studies of cathode materials for lithium ion rechargeable batteries

    NASA Astrophysics Data System (ADS)

    Saavedra Arias, Jose Javier

    We have studied the properties of spinel and layered cathode materials for Li ion rechargeable batteries. The analysis was done by first principle calculations, and experimental techniques to elucidate materials that can substitute the presently commercialized material, namely LiCoO 2. We have studied the influence of Ni substitution for Mn in spinel Li 2MnO4. To understand the effects of this substitution on the crystal structure and electronic properties, first principle DFT calculations were performed using VASP. The substitution was done systematically for up to 25% of Mn replacement by Ni in a super cell configuration. Furthermore, the influence of Ni substitution on lithium hoping pathways between the two stable Li positions was also studied by first principle calculations in LiMn 2-xNixO4. These calculations revealed that Ni substitution for Mn in LiMn2O4 indeed improved Li ion mobility. Thereafter, systematic experimental studies were performed on LiMn 2-xNixO4 (0materials were synthesized by solution route and their structural characterization was done using X-ray diffraction (XRD) and Raman spectroscopy. The electrochemical performance of LiMn2-xNi xO4 materials was evaluated in two electrode CR2032 type coin cell configuration with Li metal as anode and liquid electrolyte (1 M LiPF6 in EC:DMC=1:1 v/v). Our results showed significant enhancement in the electrochemical properties with 25% of Ni substitution in LiMn 2O4, which is in good agreement with the theoretical calculations. We also studied layered cathode materials both theoretically and experimentally. The First principle calculations in conjunction with alloy metal method were used to evaluate the average voltage and phase stability of LiMO2 (M=Co, Ni, Mn, W) systems. By formation energy analysis we established that LiNi0.8Co0.1Mn0.1O2 is a promising candidate cathode material. Single

  4. Experimental and numerical studies on laser-based powder deposition of slurry erosion resistant materials

    NASA Astrophysics Data System (ADS)

    Balu, Prabu

    cracking issue, and 3) the effect of composition and composition gradient of Ni and WC on the slurry erosion resistance over a wide range of erosion conditions. This thesis presents a set of numerical and experimental methods in order to address the challenges mentioned above. A three-dimensional (3-D) computational fluid dynamics (CFD) based powder flow model and three vision based techniques were developed in order to visualize the process of feeding the Ni-WC powder in the LBPD process. The results provide the guidelines for efficiently feeding the Ni-WC composite powder into the laser-formed molten pool. The finite element (FE) based experimentally verified 3-D thermal and thermo-mechanical models are developed in order to understand the thermal and stress evolutions in Ni-WC composite material during the LBPD process. The models address the effect of the process variables, preheating temperature, and different mass fractions of WC in Ni on thermal cycles and stress distributions within the deposited material. The slurry erosion behavior of the single and multilayered deposits of Ni-WC composite material produced by the LBPD process is investigated using an accelerated slurry erosion testing machine and a 3-D FE dynamic model. The verified model is used to identify the appropriate composition and composition gradient of Ni-WC composite material required to achieve erosion resistance over a wide range of erosion conditions.

  5. Experimental study of porosity reduction in high deposition-rate Laser Material Deposition

    NASA Astrophysics Data System (ADS)

    Zhong, Chongliang; Gasser, Andres; Schopphoven, Thomas; Poprawe, Reinhart

    2015-12-01

    For several years, the interest in Additive Manufacturing (AM) is continuously expanding, owing to the paradigm shift that new production processes, such as Laser Material Deposition (LMD), provide over conventional manufacturing technologies. With LMD, three-dimensional, complex components out of a wide range of materials can be manufactured consecutively layer-by-layer. Despite the technological advantages of the LMD process, currently achieved deposition-rates of approx. 0.5 kg/h for Inconel 718 (IN 718) remain a major concern in regards to processing times and economic feasibility. Moreover, processing conditions need to be chosen carefully or else material defects can be systematically formed either at the interface separating two adjacent clad layers, at the bonding zone or within the bulk of the layer. In this respect, the effects of powder humidity, laser power, nominal powder particle size, powder morphology and shielding gas flow rate on the porosity in laser deposited single tracks at an increased deposition-rate of approx. 2 kg/h was investigated through experiments. Based on experimental results, several approaches of reducing porosity in high deposition-rate LMD are proposed in this paper.

  6. Experimental investigation of Rayleigh Taylor instability in elastic-plastic materials

    NASA Astrophysics Data System (ADS)

    Haley, Aaron Alan; Banerjee, Arindam

    2010-11-01

    The interface of an elastic-plastic plate accelerated by a fluid of lower density is Rayleigh Taylor (RT) unstable, the growth being mitigated by the mechanical strength of the plate. The instability is observed when metal plates are accelerated by high explosives, in explosive welding, and in volcanic island formation due to the strength of the inner crust. In contrast to the classical case involving Newtonian fluids, RT instability in accelerated solids is not well understood. The difficulties for constructing a theory for the linear growth phase in solids is essentially due to the character of elastic-plastic constitutive properties which has a nonlinear dependence on the magnitude of the rate of deformation. Experimental investigation of the phenomena is difficult due to the exceedingly small time scales (in high energy density experiments) and large measurement uncertainties of material properties. We performed experiments on our Two-Wheel facility to study the linear stage of the incompressible RT instability in elastic-plastic materials (yogurt) whose properties were well characterized. Rotation of the wheels imparted a constant centrifugal acceleration on the material interface that was cut with a small sinusoidal ripple. The controlled initial conditions and precise acceleration amplitudes are levied to investigate transition from elastic to plastic deformation and allow accurate and detailed measurements of flow properties.

  7. The actual goals of geoethics

    NASA Astrophysics Data System (ADS)

    Nemec, Vaclav

    2014-05-01

    The most actual goals of geoethics have been formulated as results of the International Conference on Geoethics (October 2013) held at the geoethics birth-place Pribram (Czech Republic): In the sphere of education and public enlightenment an appropriate needed minimum know how of Earth sciences should be intensively promoted together with cultivating ethical way of thinking and acting for the sustainable well-being of the society. The actual activities of the Intergovernmental Panel of Climate Changes are not sustainable with the existing knowledge of the Earth sciences (as presented in the results of the 33rd and 34th International Geological Congresses). This knowledge should be incorporated into any further work of the IPCC. In the sphere of legislation in a large international co-operation following steps are needed: - to re-formulate the term of a "false alarm" and its legal consequences, - to demand very consequently the needed evaluation of existing risks, - to solve problems of rights of individuals and minorities in cases of the optimum use of mineral resources and of the optimum protection of the local population against emergency dangers and disasters; common good (well-being) must be considered as the priority when solving ethical dilemmas. The precaution principle should be applied in any decision making process. Earth scientists presenting their expert opinions are not exempted from civil, administrative or even criminal liabilities. Details must be established by national law and jurisprudence. The well known case of the L'Aquila earthquake (2009) should serve as a serious warning because of the proven misuse of geoethics for protecting top Italian seismologists responsible and sentenced for their inadequate superficial behaviour causing lot of human victims. Another recent scandal with the Himalayan fossil fraud will be also documented. A support is needed for any effort to analyze and to disclose the problems of the deformation of the contemporary

  8. Experimental verification of the inverse Doppler effect in negative-index material

    NASA Astrophysics Data System (ADS)

    Feng, Lie; Chen, Jiabi; Wang, Yan; Geng, Tao; Zhuang, Songlin

    2010-10-01

    μResearch of negative-index material (NIM) is a very hot developing research field in recent years. NIM is also called left-handed material (LHM), in which the electric field [see manuscript], the magnetic field [see manuscript] and the wave vector [see manuscript] are not composed of a set of right-handed coordinates but a set of left-handed coordinates. Thus the action of electromagnetic waves in both left-handed material and right-handed material is just the opposite, for instance, the negative refraction phenomenon, the inverse Doppler effect and so on. Here we report the explicit result of the inverse Doppler effect through a photonic crystal (PC) prism at 10.6m wavelength for the first time, and the result we get from the experiment is much similar to the theoretical analysis we have deduced before. During the experiment, the CO2 laser is used as a light source, and the PC prism is used as a sample, which can move a tiny distance (1mm) uniformly with a translating stage. Based on the method of optical heterodyne, we let the emergent light from the output surface of PC prism and the reference light from light source interfere at the surface of the detector. When the translating stage moves towards the detector, the optical paths in the PC prism will be changed, and then the Doppler frequency shift will be generated. Though several different samples have been tested repeatedly, the results we get are extraordinarily similar. So we can be sure that the inverse Doppler effect really exists in the NIM at optical frequencies. To our best knowledge, this is the only experimental verification of the inverse Doppler effect in the NIM at optical frequencies at home and aboard.

  9. In-situ material-motion diagnostics and fuel radiography in experimental reactors

    SciTech Connect

    DeVolpi, A.

    1982-01-01

    Material-motion monitoring has become a routine part of in-pile transient reactor-safety experiments. Diagnostic systems, such as the fast-neutron hodoscope, were developed for the purpose of providing direct time-resolved data on pre-failure fuel motion, cladding-breach time and location, and post-failure fuel relocation. Hodoscopes for this purpose have been installed at TREAT and CABRI; other types of imaging systems that have been tested are a coded-aperture at ACRR and a pinhole at TREAT. Diagnostic systems that use penetrating radiation emitted from the test section can non-invasively monitor fuel without damage to the measuring instrument during the radiographic images of test sections installed in the reator. Studies have been made of applications of hodoscopes to other experimental reactors, including PBF, FARET, STF, ETR, EBR-II, SAREF-STF, and DMT.

  10. [Modeling and experimental study on frequency-domain electricity properties of biological materials].

    PubMed

    Tian, Hua; Luo, Shiqiang; Zhang, Rui; Yang, Gang; Huang, Hua

    2009-12-01

    Frequency-domain electricity properties of four objects, including bullfrog skin, bullfrog muscle, triply distilled water and 0.9% NaCl, were tested in the range of 100Hz-10MHz using home-made electrode and measuring system. The experimental results showed that the resistance of 0.9% NaCl decreased dramatically, that the amplitude frequency characteristics of bullfrog's muscle and skin were similar, but that of triply distilled water did not change significantly. The frequency dependence of 0.9% NaCl showed that the electrode had great influence on the measuring system, so a new equivalent circuit model based on the electrode system was needed. These findings suggest that the new five-parameter equivalent circuit model, which embodies considerations on the interaction between electrodes and tissues, is a reasonable equivalent circuit for studying the electrical characteristics of biological materials.

  11. An Experimental and Computational Study of Directional Solidification in Transparent Materials

    NASA Technical Reports Server (NTRS)

    Simpson, James E.; deGroh, Henry C., III; Garimella, Suresh V.

    1999-01-01

    An experimental and numerical study of the horizontal Bridgman growth of pure succinonitrile (SCN) and of a succinonitrile- 1.0 mol.% acetone alloy (SCN- 1.0 mol.% ACE) has been performed. Experiments at growth rates of 0, 2 and 40 micron/s were investigated. The solid/liquid interface was stable (non-dendritic and non-cellular); however, it was not flat. Rather, it was significantly distorted by the influence of convection in the melt and, for the growth cases, by the moving temperature boundary conditions along the ampoule. For the alloy, the interface was.determined to be unstable at growth rates greater than 2.8 micron/s, but stable for the no-growth and 2 micron/s growth cases. When compared to the pure SCN interface, the alloy interface forms closer to the cold zone, indicating that the melting temperature has been suppressed by the addition of the alloying element. Two-dimensional computer simulations were performed for the no-growth case for both the pure and alloy materials. These simulations indicate that a primary longitudinal convective cell is formed in the melt. The maximum magnitude of velocity was calculated to be 1.515 mm/s for pure SCN and 1.724 mm/s for the alloy. The interface shape predicted by the computer simulation agrees well with the experimentally determined shape for the pure SCN case. In ongoing work, numerical simulations of the process during growth conditions are being performed.

  12. Numerical and Experimental Analysis on Inorganic Phase Change Material Usage in Construction

    NASA Astrophysics Data System (ADS)

    Muthuvel, S.; Saravanasankar, S.; Sudhakarapandian, R.; Muthukannan, M.

    2014-12-01

    This work demonstrates the significance of Phase Change Material (PCM) in the construction of working sheds and product storage magazines in fireworks industries to maintain less temperature variation by passive cooling. The inorganic PCM, namely Calcium Chloride Hexahydrate (CCH) is selected in this study. First, the performance of two models with inbuilt CCH was analysed, using computational fluid dynamics. A significant change in the variation of inner wall temperature was observed, particularly during the working hours. This is mainly due to passive cooling, where the heat transfer from the surroundings to the room is partially used for the phase change from solid to liquid. The experiment was carried out by constructing two models, one with PCM packed in hollow brick walls and roof, and the other one as a conventional construction. The experimental results show that the temperature of the room got significantly reduced up to 7 °C. The experimental analysis results had good agreement with the numerical analysis results, and this reveals the advantage of the PCM in the fireworks industry construction.

  13. Experimental and theoretical study of organometallic radiation-protective materials adapted to radiation sources with a complex isotopic composition

    SciTech Connect

    Russkikh, I. M.; Seleznev, E. N.; Tashlykov, O. L. Shcheklein, S. E.

    2015-12-15

    The significance of optimizing the content of components of a radiation-protective material, which is determined by the isotopic composition of radioactive contamination, depending on the reactor type, operating time, and other factors is demonstrated. The results of computational and experimental investigation of the gamma-radiation attenuation capacity of homogenous radiation-protective materials with different fillers are reported.

  14. Experimental Evidence of Classical Conditioning and Microscopic Engrams in an Electroconductive Material

    PubMed Central

    Karbowski, Lukasz M.; Persinger, Michael A.

    2016-01-01

    Synthetic experimental substrates are indispensable tools which can allow researchers to model biological processes non-invasively in three-dimensional space. In this study, we investigated the capacities of an electroconductive material whose properties converge upon those of the brain. An electrically conductive material composed of carbohydrates, proteins, fats, ions, water, and trace amounts of other organic compounds and minerals was classically conditioned as inferred by electrophysiological measurements. Spectral densities evoked during the display of a conditioned stimulus (CS) probe were strongly congruent with those displayed during the conditioned-unconditioned stimulus pairing (CS-UCS). The neutral stimulus consisted of the pulsed light from a LED. The unconditioned stimulus was an alternating current. Interstimulus intervals >130 ms did not result in conditioned responses. Microscopic analysis of the chemically-fixed substratum revealed 10–200 μm wide ‘vessel structures’ within samples exposed to a stimulus. Greater complexity (increased fractal dimensions) was clearly discernable by light microscopy for stained sections of fixed samples that had been conditioned compared to various controls. The denser pixels indicated greater concentration of stain and increased canalization. Implications for learning and memory formation are discussed. PMID:27764215

  15. Experimental investigation of plastic finned-tube heat exchangers, with emphasis on material thermal conductivity

    SciTech Connect

    Chen, Lin; Li, Zhen; Guo, Zeng-Yuan

    2009-07-15

    In this paper, two modified types of polypropylene (PP) with high thermal conductivity up to 2.3 W/m K and 16.5 W/m K are used to manufacture the finned-tube heat exchangers, which are prospected to be used in liquid desiccant air conditioning, heat recovery, water source heat pump, sea water desalination, etc. A third plastic heat exchanger is also manufactured with ordinary PP for validation and comparison. Experiments are carried out to determine the thermal performance of the plastic heat exchangers. It is found that the plastic finned-tube heat exchanger with thermal conductivity of 16.5 W/m K can achieve overall heat transfer coefficient of 34 W/m{sup 2} K. The experimental results are compared with calculation and they agree well with each other. Finally, the effect of material thermal conductivity on heat exchanger thermal performance is studied in detail. The results show that there is a threshold value of material thermal conductivity. Below this value improving thermal conductivity can considerably improve the heat exchanger performance while over this value improving thermal conductivity contributes very little to performance enhancement. For the finned-tube heat exchanger designed in this paper, when the plastic thermal conductivity can reach over 15 W/m K, it can achieve more than 95% of the titanium heat exchanger performance and 84% of the aluminum or copper heat exchanger performance with the same dimension. (author)

  16. Experimental measurements of material damping in free fall with tuneable excitation

    NASA Technical Reports Server (NTRS)

    Crawley, E. F.; Mohr, D. G.

    1983-01-01

    An experimental method of measuring material damping of a specimen in free fall has been developed. An initially simply-supported test specimen was simultaneously excited and lofted into free fall with a spring-mass launcher. The launcher could be tuned to produce varying initial stress amplitude levels in the specimens. Damping information was obtained from the transient response of the specimens while in free fall in a vacuum. A dynamic model of the launch process was developed which indicates the range of frequency and initial specimen stress amplitude over which tests can be performed. To verify the facility, material damping was measured in 2024-T3 aluminum, and (+ or - 45)2s AS1/3501-6 graphite/epoxy. Free-free frequencies ranged from 20-357 Hz in aluminum, and from 18-171 Hz in the (+ or - 45)2s specimens. Damping values in aluminum were found to be close to theoretical values and independent of stress levels below 130 MPa (18.7 Ksi). Damping ratios in the (+ or - 45)2s graphite/epoxy specimens were found to be largely independent of stress levels below 43.8 MPa (6.35 Ksi) and only slightly dependent on frequency. A small dependence of the frequency of free vibration on specimen stress amplitude was also noted.

  17. The effects of energetic proton bombardment on polymeric materials: Experimental studies and degradation models

    NASA Technical Reports Server (NTRS)

    Coulter, D. R.; Gupta, A.; Smith, M. V.; Fornes, R. E.

    1986-01-01

    This report describes 3 MeV proton bombardment experiments on several polymeric materials of interest to NASA carried out on the Tandem Van De Graff Accelerator at the California Institute of Technology's Kellogg Radiation Laboratory. Model aromatic and aliphatic polymers such as poly(1-vinyl naphthalene) and poly(methyl methacrylate), as well as polymers for near term space applications such as Kapton, Epoxy and Polysulfone, have been included in this study. Chemical and physical characterization of the damage products have been carried out in order to develop a model of the interaction of these polymers with the incident proton beam. The proton bombardment methodology developed at the Jet Propulsion Laboratory and reported here is part of an ongoing study on the effects of space radiation on polymeric materials. The report is intended to provide an overview of the mechanistic, as well as the technical and experimental, issues involved in such work rather than to serve as an exhaustive description of all the results.

  18. Experimental determination of Grunieisen gamma for two dissimilar materials (PEEK and Al 5083) via the shock-reverberation technique

    NASA Astrophysics Data System (ADS)

    Roberts, Andrew; Appleby-Thomas, Gareth; Hazell, Paul

    2011-06-01

    Following multiple loading events the resultant shock state of a material will lie away from the principle Hugoniot. Prediction of such states requires knowledge of a materials equation-of-state. The material-specific variable Grunieisen gamma (Γ) defines the shape of ``off-Hugoniot'' points in energy-volume-pressure space. Experimentally the shock-reverberation technique (based on the principle of impedance-matching) has previously allowed estimation of the first-order Grunieisen gamma term (Γ1) for a silicone elastomer. Here, this approach was employed to calculate Γ1 for two dissimilar materials, Polyether ether ketone (PEEK) and the armour-grade aluminium alloy 5083 (H32); thereby allowing discussion of limitations of this technique in the context of plate-impact experiments employing Manganin stress gauges. Finally, the experimentally determined values for Γ1 were further refined by comparison between experimental records and numerical simulations carried out using the commercial code ANYSYS Autodyn®.

  19. Soft material adhesion characterization for in vivo locomotion of robotic capsule endoscopes: Experimental and modeling results.

    PubMed

    Kern, Madalyn D; Ortega Alcaide, Joan; Rentschler, Mark E

    2014-11-01

    The objective of this work is to validate an experimental method and nondimensional model for characterizing the normal adhesive response between a polyvinyl chloride based synthetic biological tissue substrate and a flat, cylindrical probe with a smooth polydimethylsiloxane (PDMS) surface. The adhesion response is a critical mobility design parameter of a Robotic Capsule Endoscope (RCE) using PDMS treads to provide mobility to travel through the gastrointestinal tract for diagnostic purposes. Three RCE design characteristics were chosen as input parameters for the normal adhesion testing: pre-load, dwell time and separation rate. These parameters relate to the RCE׳s cross sectional dimension, tread length, and tread speed, respectively. An inscribed central composite design (CCD) prescribed 34 different parameter configurations to be tested. The experimental adhesion response curves were nondimensionalized by the maximum stress and total displacement values for each test configuration and a mean nondimensional curve was defined with a maximum relative error of 5.6%. A mathematical model describing the adhesion behavior as a function of the maximum stress and total displacement was developed and verified. A nonlinear regression analysis was done on the maximum stress and total displacement parameters and equations were defined as a function of the RCE design parameters. The nondimensional adhesion model is able to predict the adhesion curve response of any test configuration with a mean R(2) value of 0.995. Eight additional CCD studies were performed to obtain a qualitative understanding of the impact of tread contact area and synthetic material substrate stiffness on the adhesion response. These results suggest that the nondimensionalization technique for analyzing the adhesion data is sufficient for all values of probe radius and substrate stiffness within the bounds tested. This method can now be used for RCE tread design optimization given a set of

  20. Experimental Study of Novel Materials and Module for Cryogenic (4K) Superconducting Multi-Chip Modules

    NASA Astrophysics Data System (ADS)

    John, Ranjith Samuel E.

    Niobium based superconducting electronics (SCE) are the fastest known digital logic which operate at 100GHz and greater. Nevertheless, the performance of the SCE device depends on the temperature of the SCE integrated circuits being maintained between 4.2 -- 4.25 K. Additionally, as semiconductors are slowly approaching their performance limitations the SCE devices are viewed as a viable alternative for high end computing and commercial wireless applications. However, the successful commercialization of SCE's requires the demonstration of these devices in multichip module (MCM) architecture. Thus the stringent thermal constraint and the complex MCM architecture require an innovative method for thermal management. This research addressed the above challenges by using a nano-engineered polymer adhesive, namely, single walled carbon nanotube (SWCNT) integrated epoxy as underfill for the packaging of SCE in MCM architecture. The current research distinguished itself by (1) examining the thermal management issues across a single chip SCE-MCM and developing a thermal model based on literature and experimental analysis, (2) developing a new material, namely SWCNT-integrated epoxy whose thermal and electrical performance were analyzed as a function of SWCNT loading and (3) demonstrating the thermal and electrical performance of single chip SCE-MCM test structure and 2D SCE-MCM test structure with SWCNT-epoxy as underfill. The thermal analysis of the single chip SCE-MCM was studied by modeling, which illustrated that cryogenic underfill with thermal conductivity of 0.04 W/mK plays a vital role in thermal management of SCE-MCMs. A SWCNT-epoxy underfill material which was thermally conductive but electrically insulating was developed and the experimental verification of the thermal model was completed by studying the thermal performance of single chip SCE MCMs with and without SWCNT-epoxy as underfill. It was determined that the heat transport between the SCE chip and SCE

  1. A robust nanoscale experimental quantification of fracture energy in a bilayer material system

    PubMed Central

    Lau, Denvid; Broderick, Kurt; Buehler, Markus J.; Büyüköztürk, Oral

    2014-01-01

    Accurate measurement of interfacial properties is critical any time two materials are bonded—in composites, tooth crowns, or when biomaterials are attached to the human body. Yet, in spite of this importance, reliable methods to measure interfacial properties between dissimilar materials remain elusive. Here we present an experimental approach to quantify the interfacial fracture energy Γi that also provides unique mechanistic insight into the interfacial debonding mechanism at the nanoscale. This approach involves deposition of an additional chromium layer (superlayer) onto a bonded system, where interface debonding is initiated by the residual tensile stress in the superlayer, and where the interface can be separated in a controlled manner and captured in situ. Contrary to earlier methods, our approach allows the entire bonded system to remain in an elastic range during the debonding process, such that Γi can be measured accurately. We validate the method by showing that moisture has a degrading effect on the bonding between epoxy and silica, a technologically important interface. Combining in situ through scanning electron microscope images with molecular simulation, we find that the interfacial debonding mechanism is hierarchical in nature, which is initiated by the detachment of polymer chains, and that the three-dimensional covalent network of the epoxy-based polymer may directly influence water accumulation, leading to the reduction of Γi under presence of moisture. The results may enable us to design more durable concrete composites that could be used to innovate transportation systems, create more durable buildings and bridges, and build resilient infrastructure. PMID:25097263

  2. Linguistic Theory and Actual Language.

    ERIC Educational Resources Information Center

    Segerdahl, Par

    1995-01-01

    Examines Noam Chomsky's (1957) discussion of "grammaticalness" and the role of linguistics in the "correct" way of speaking and writing. It is argued that the concern of linguistics with the tools of grammar has resulted in confusion, with the tools becoming mixed up with the actual language, thereby becoming the central element in a metaphysical…

  3. El Observatorio Gemini - Status actual

    NASA Astrophysics Data System (ADS)

    Levato, H.

    Se hace una breve descripción de la situación actual del Observatorio Gemini y de las últimas decisiones del Board para incrementar la eficiencia operativa. Se hace también una breve referencia al uso argentino del observatorio.

  4. Blast wave loading pathways in heterogeneous material systems-experimental and numerical approaches.

    PubMed

    Selvan, Veera; Ganpule, Shailesh; Kleinschmit, Nick; Chandra, Namas

    2013-06-01

    Blast waves generated in the field explosions impinge on the head-brain complex and induce mechanical pressure pulses in the brain resulting in traumatic brain injury. Severity of the brain injury (mild to moderate to severe) is dependent upon the magnitude and duration of the pressure pulse, which in turn depends on the intensity and duration of the oncoming blast wave. A fluid-filled cylinder is idealized to represent the head-brain complex in its simplest form; the cylinder is experimentally subjected to an air blast of Friedlander type, and the temporal variations of cylinder surface pressures and strains and fluid pressures are measured. Based on these measured data and results from computational simulations, the mechanical loading pathways from the external blast to the pressure field in the fluid are identified; it is hypothesized that the net loading at a given material point in the fluid comprises direct transmissive loads and deflection-induced indirect loads. Parametric studies show that the acoustic impedance mismatches between the cylinder and the contained fluid as well as the flexural rigidity of the cylinder determine the shape/intensity of pressure pulses in the fluid. PMID:23699714

  5. Design and Development of a Composite Dome for Experimental Characterization of Material Permeability

    NASA Technical Reports Server (NTRS)

    Estrada, Hector; Smeltzer, Stanley S., III

    1999-01-01

    This paper presents the design and development of a carbon fiber reinforced plastic dome, including a description of the dome fabrication, method for sealing penetrations in the dome, and a summary of the planned test series. This dome will be used for the experimental permeability characterization and leakage validation of composite vessels pressurized using liquid hydrogen and liquid nitrogen at the Cryostat Test Facility at the NASA Marshall Space Flight Center (MSFC). The preliminary design of the dome was completed using membrane shell analysis. Due to the configuration of the test setup, the dome will experience some flexural stresses and stress concentrations in addition to membrane stresses. Also, a potential buckling condition exists for the dome due to external pressure during the leak testing of the cryostat facility lines. Thus, a finite element analysis was conducted to assess the overall strength and stability of the dome for each required test condition. Based on these results, additional plies of composite reinforcement material were applied to local regions on the dome to alleviate stress concentrations and limit deflections. The dome design includes a circular opening in the center for the installation of a polar boss, which introduces a geometric discontinuity that causes high stresses in the region near the hole. To attenuate these high stresses, a reinforcement system was designed using analytical and finite element analyses. The development of a low leakage polar boss system is also investigated.

  6. Experimental measurement of a shipboard fire environment with simulated radioactive materials packages

    SciTech Connect

    Koski, J.A.; Wix, S.D.; Beene, D.E. Jr.

    1996-12-31

    Results from a series of eight test fires ranging in size from 2.2 to 18.8 MW conducted aboard the Coast Guard fire test ship Mayo Lykes at Mobile, Alabama are presented and discussed. Tests aboard the break-bulk type cargo ship consisted of heptane spray fires simulating engine room and galley fires, wood crib fires simulating cargo hold fires, and pool fires staged for comparison to land-based regulatory fire results. Primary instrumentation for the tests consisted of two pipe calorimeters that simulated a typical package shape for radioactive materials packages. The calorimeters were both located adjacent to the fires and on the opposite side of the cargo hold bulkhead nearest the fire. The calorimeters were constructed from 1.5 m length sections of nominal 2 foot diameter schedule 60 steel pipe. Type K thermocouples were attached at 12 locations on the circumference and ends of the calorimeter. Fire heat fluxes to the calorimeter surfaces were estimated with the use of the Sandia SODDIT inverse heat conduction code. Experimental results from all types of tests are discussed, and some comparisons are made between the environments found on the ship and those found in land-based pool fire tests.

  7. An experimental study on seepage behavior of sandstone material with different gas pressures

    NASA Astrophysics Data System (ADS)

    Yang, Sheng-Qi; Huang, Yan-Hua; Jiao, Yu-Yong; Zeng, Wei; Yu, Qing-Lei

    2015-12-01

    The seepage evolution characteristic of brittle rock materials is very significant for the stability and safety of rock engineering. In this research, a series of conventional triaxial compression and gas seepage tests were carried out on sandstone specimens with a rock mechanics servo-controlled testing system. Based on the experimental results, the relationship between permeability and deformation is firstly analyzed in detail. The results show that the permeability-axial strain curve can be divided into the following five phases: the phase of micro-defects closure, the phase of linear elastic deformation, the phase of nonlinear deformation, the phase of post-peak stress softening and the phase of residual strength. The seepage evolution characteristic is also closely correlated with the volumetric deformation according to the relationship between permeability and volumetric strain. It is found that the gas seepage pressure has a great effect on the permeability evolution, i.e. permeability coefficients increase with increasing gas seepage pressures. Finally, the influence of gas seepage pressures on the failure behavior of brittle sandstone specimens is discussed.

  8. Computational and Experimental Investigations Into the Mass Loss of a Carbon Material in the Sublimation Regime of its Thermochemical Destruction

    NASA Astrophysics Data System (ADS)

    Gorskii, V. V.; Zolotarev, S. L.; Olenicheva, A. A.

    2015-01-01

    The authors give results of an experimental investigation into the ablation characteristics of a modern fi ne granular carbon material in the high-enthalpy jet of a TT-1 arc-heated facility [1] ("TsNIImash" Federal State Unitary Enterprise), and also results of computational and experimental investigations into the parameters of the jet of this facility. Data given in the article provide a basis for studying the regularities of the mass loss of the carbon material in a sublimation regime of its thermochemical destructioncpb

  9. Effect of varying experimental conditions on the viscosity of α-pinene derived secondary organic material

    NASA Astrophysics Data System (ADS)

    Grayson, James W.; Zhang, Yue; Mutzel, Anke; Renbaum-Wolff, Lindsay; Boge, Olaf; Kamal, Saeid; Herrmann, Hartmut; Martin, Scot T.; Bertram, Allan K.

    2016-05-01

    Knowledge of the viscosity of particles containing secondary organic material (SOM) is useful for predicting reaction rates and diffusion in SOM particles. In this study we investigate the viscosity of SOM particles as a function of relative humidity and SOM particle mass concentration, during SOM synthesis. The SOM was generated via the ozonolysis of α-pinene at < 5 % relative humidity (RH). Experiments were carried out using the poke-and-flow technique, which measures the experimental flow time (τexp, flow) of SOM after poking the material with a needle. In the first set of experiments, we show that τexp, flow increased by a factor of 3600 as the RH increased from < 0.5 RH to 50 % RH, for SOM with a production mass concentration of 121 μg m-3. Based on simulations, the viscosities of the particles were between 6 x 105 and 5 x 107 Pa s at < 0.5 % RH and between 3 x 102 and 9 x 103 Pa s at 50 % RH. In the second set of experiments we show that under dry conditions τexp, flow decreased by a factor of 45 as the production mass concentration increased from 121 to 14 000 μg m-3. From simulations of the poke-and-flow experiments, the viscosity of SOM with a production mass concentration of 14 000 μg m-3 was determined to be between 4 x 104 and 1.5 x 106 Pa s compared to between 6 x 105 and 5 x 107 Pa s for SOM with a production mass concentration of 121 μg m-3. The results can be rationalized by a dependence of the chemical composition of SOM on production conditions. These results emphasize the shifting characteristics of SOM, not just with RH and precursor type, but also with the production conditions, and suggest that production mass concentration and the RH at which the viscosity was determined should be considered both when comparing laboratory results and when extrapolating these results to the atmosphere.

  10. Effect of varying experimental conditions on the viscosity of α-pinene derived secondary organic material

    NASA Astrophysics Data System (ADS)

    Grayson, J. W.; Zhang, Y.; Mutzel, A.; Renbaum-Wolff, L.; Böge, O.; Kamal, S.; Herrmann, H.; Martin, S. T.; Bertram, A. K.

    2015-11-01

    To predict the role of secondary organic material (SOM) particles in climate, visibility, and health, information on the viscosity of particles containing SOM is required. In this study we investigate the viscosity of SOM particles as a function of relative humidity and SOM particle mass concentration during SOM synthesis. The SOM was generated via the ozonolysis of α-pinene at < 5 % relative humidity (RH). Experiments were carried out using the poke-and-flow technique, which measures the experimental flow time (τexp, flow) of SOM after poking the material with a needle. In the first set of experiments, we show that τexp, flow increased by a factor of 3600 as the RH increased from < 0.5 to 50 % RH, for SOM with a production mass concentration of 121 μg m-3. Based on simulations, the viscosities of the particles were between 6 × 105 and 5 × 107 Pa s at < 0.5 % RH and between 3 × 102 and 9 × 103 Pa s at 50 % RH. In the second set of experiments we show that under dry conditions τexp, flow decreased by a factor of 45 as the production mass concentration increased from 121 to 14 000 μg m-3. From simulations of the poke-and-flow experiments, the viscosity of SOM with a production mass concentration of 14 000 μg m-3 was determined to be between 4 × 104 and 1.5 × 106 Pa s compared to between 6 × 105 and 5 × 107 Pa s for SOM with a production mass concentration of 121 μg m-3. The results can be rationalised by a dependence of the chemical composition of SOM on production conditions. These results emphasise the shifting characteristics of SOM, not just with RH and precursor type, but also with the production conditions, and suggest that production mass concentration and the RH at which the viscosity was determined should be considered both when comparing laboratory results and when extrapolating these results to the atmosphere.

  11. Experimental method development for estimating solid-phase diffusion coefficients and material/air partition coefficients of SVOCs

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoyu; Guo, Zhishi; Roache, Nancy F.

    2014-06-01

    The solid-phase diffusion coefficient (Dm) and material/air partition coefficient (Kma) are key parameters for characterizing the sources and transport of semivolatile organic compounds (SVOCs) in the indoor environment. In this work, a new experimental method was developed to estimate parameters Dm and Kma. The SVOCs chosen for study were polychlorinated biphenyl (PCB) congeners, including PCB-52, PCB-66, PCB-101, PCB-110, and PCB-118. The test materials included polypropylene, high density polyethylene, low density polyethylene, polytetrafluoroethylene, polyether ether ketone, glass, stainless steel and concrete. Two 53-L environmental chambers were connected in series, with the relatively stable SVOCs source in the source chamber and the test materials, made as small “buttons”, in the test chamber. Prior to loading the test chamber with the test materials, the test chamber had been dosed with SVOCs for 12 days to “coat” the chamber walls. During the tests, the material buttons were removed from the test chamber at different exposure times to determine the amount of SVOC absorbed by the buttons. SVOC concentrations at the inlet and outlet of the test chamber were also monitored. The data were used to estimate the partition and diffusion coefficients by fitting a sink model to the experimental data. The parameters obtained were employed to predict the accumulation of SVOCs in the sink materials using an existing mass transfer model. The model prediction agreed reasonably well with the experimental data.

  12. Material unaccounted for at the Southwest Experimental Fast Oxide Reactor: The SEFOR MUF

    SciTech Connect

    Higinbotham, W.A.

    1994-11-07

    The U.S. Atomic Energy Commission contracted with the General Electric Company to design, construct, and operate the Southwest Experimental Fast Oxide Reactor (SEFOR) to measure the Doppler effect for fast neutron breeder reactors. It contracted with Nuclear Fuel Services to fabricate the fuel rods for the reactor. When the reactor went critical in May, 1969, it appeared that some of the mixed uranium-plutonium oxide (MOX) fuel rods did not contain the specified quantity of plutonium. The SEFOR operators soon found several fuel rods which appeared to be low in plutonium. The safeguards group at Brookhaven was asked to look into the problem and, if possible, determine how much plutonium was missing from the unirradiated rods and from the larger number which had been slightly irradiated in the reactor. It was decided that the plutonium content of the unirradiated and irradiated rods could be measured relative to a reference rod using a high resolution gamma-ray detector and also by neutron measurements using an auto-correlation circuit recently developed at the Naval Research Laboratory (NRL). During the next two years, Brookhaven personnel and C.V. Strain of NRL made several trips to the SEFOR reactor. About 250 of the 775 rods were measured by two or more methods, using a sodium-iodide detector, a high-resolution germanium detector, a neutron detector, or the reactor (to measure reactivity). The research team concluded that 4.6 {+-} 0.46 kg of plutonium was missing out of the 433 kg that the rods should have contained. This report describes the SEFOR experiment and the procedures used to determine the material unaccounted for, or MUF.

  13. Experimental Research of High-Energy Capabilities of Material Recognition by Dual-Energy Method for the Low- Dose Radiation

    NASA Astrophysics Data System (ADS)

    Abashkin, A.; Osipov, S.; Chakhlov, S.; Shteyn, A.

    2016-06-01

    The algorithm to produce primary radiographs, its transformation by dual energy method and recognition of the object materials were enhanced based on the analysis of experimental results. The experiments were carried out at the inspection complex with high X- ray source - betatron MIB 4/9 in Tomsk Polytechnic University. For the reduced X -ray dose rate, the possibility of recognition of the object materials with thickness from 20 to 120 g/cm2 was proved under the condition that as the dose rate is reduced by the defined number of times, the segment of the image fragment with the reliably identified material will increase by the same number of times.

  14. Dynamic material characterization of the human heel pad based on in vivo experimental tests and numerical analysis.

    PubMed

    Kardeh, M; Vogl, T J; Huebner, F; Nelson, K; Stief, F; Silber, G

    2016-09-01

    A numerical-experimental, proof-of-concept approach is described to characterize the mechanical material behavior of the human heel pad under impact conditions similar to a heel strike while running. A 3D finite-element model of the right foot of a healthy female subject was generated using magnetic resonance imaging. Based on quasi-static experimental testing of the subject's heel pad, force-displacement data was obtained. Using this experimental data as well as a numerical optimization algorithm, an inverse finite-element analysis and the 3D model, heel pad hyperelastic (long-term) material parameters were determined. Applying the same methodology, based on the dynamic experimental data from the impact test and obtained long-term parameters, linear viscoelastic parameters were established with a Prony series. Model validation was performed employing quasi-static and dynamic force-displacement data. Coefficients of determination when comparing model to experimental data during quasi-static and dynamic (initial velocity: 1480mm/s) procedure were R(2) = 0.999 and R(2) = 0.990, respectively. Knowledge of these heel pad material parameters enables realistic numerical analysis to evaluate internal stress and strain in the heel pad during different quasi-static or dynamic load conditions.

  15. Experimental Method Development for Estimating Solid-phase Diffusion Coefficients and Material/Air Partition Coefficients of SVOCs

    EPA Science Inventory

    The solid-phase diffusion coefficient (Dm) and material-air partition coefficient (Kma) are key parameters for characterizing the sources and transport of semivolatile organic compounds (SVOCs) in the indoor environment. In this work, a new experimental method was developed to es...

  16. Environmental Effect on Evolutionary Cyclic Plasticity Material Parameters of 316 Stainless Steel: An Experimental & Material Modeling Approach

    SciTech Connect

    Mohanty, Subhasish; Soppet, William K.; Majumdar, Saurin; Natesan, Ken

    2014-09-20

    This report provides an update on an earlier assessment of environmentally assisted fatigue for light water reactor (LWR) materials under extended service conditions. This report is a deliverable under the work package for environmentally assisted fatigue in the Light Water Reactor Sustainability (LWRS) program. The overall objective of this LWRS project is to assess the degradation by environmentally assisted cracking/fatigue of LWR materials such as various alloy base metals and their welds used in reactor coolant system piping. This effort is to support the Department of Energy LWRS program for developing tools to understand the aging/failure mechanism and to predict the remaining life of LWR components for anticipated 60-80 year operation.

  17. Experimental investigation of pressure responsive 'smart' materials found in the natural world

    NASA Astrophysics Data System (ADS)

    Greene, George W.

    The unique ability to sense environmental stimuli and respond appropriately in a controlled and reversible fashion is a distinguishing characteristic of a novel class of materials collectively known as 'smart,' 'adaptive,' or 'responsive' materials. This seemingly 'smart' behavior is, thus, controlled by internal 'feedback loops' generated by the interconnectivity of various system elements which enables them to operate cooperatively and exhibit more complex behaviors as a collective. This thesis investigates, experimentally, three natural systems found in both the biological and non-biological domains which exhibit responsive or adaptive behaviors in the presence of external mechanical pressures by exploiting uniquely different chemical and physical principles. The first system focuses on articular cartilage, an example of an adaptive material which utilizes its distinctive hierachical, multi-scale structure in order to adjust and change its physical and lubricating properties to suit the specific needs under a broad range of normal and shear stresses. A compression cell designed to fit inside an NMR spectrometer was used to investigate the in situ mechanical strain response, structural changes to the internal pore structure, and the diffusion and flow of interstitial water in full thickness cartilage samples as it was deforming dynamically under a constant compressive load (pressure). We distinguish between the hydrostatic pressure acting on the interstitial fluid and the pore pressure acting on the cartilage fibril network. Our results show that properties related to the pore matrix microstructure such as diffusion and hydraulic conductivity are strongly influenced by the hydrostatic pressure in the interstitial fluid of the dynamically deforming cartilage which differ significantly from the properties measured under static i.e. equilibrium loading conditions (when the hydrostatic pressure has relaxed back to zero). The magnitude of the hydrostatic fluid

  18. Modeling defect cluster evolution in irradiated structural materials: Focus on comparing to high-resolution experimental characterization studies

    DOE PAGES

    Wirth, Brian D.; Hu, Xunxiang; Kohnert, Aaron; Xu, Donghua

    2015-03-02

    Exposure of metallic structural materials to irradiation environments results in significant microstructural evolution, property changes, and performance degradation, which limits the extended operation of current generation light water reactors and restricts the design of advanced fission and fusion reactors. Further, it is well recognized that these irradiation effects are a classic example of inherently multiscale phenomena and that the mix of radiation-induced features formed and the corresponding property degradation depend on a wide range of material and irradiation variables. This inherently multiscale evolution emphasizes the importance of closely integrating models with high-resolution experimental characterization of the evolving radiation-damaged microstructure. Lastly,more » this article provides a review of recent models of the defect microstructure evolution in irradiated body-centered cubic materials, which provide good agreement with experimental measurements, and presents some outstanding challenges, which will require coordinated high-resolution characterization and modeling to resolve.« less

  19. Modeling defect cluster evolution in irradiated structural materials: Focus on comparing to high-resolution experimental characterization studies

    SciTech Connect

    Wirth, Brian D.; Hu, Xunxiang; Kohnert, Aaron; Xu, Donghua

    2015-03-02

    Exposure of metallic structural materials to irradiation environments results in significant microstructural evolution, property changes, and performance degradation, which limits the extended operation of current generation light water reactors and restricts the design of advanced fission and fusion reactors. Further, it is well recognized that these irradiation effects are a classic example of inherently multiscale phenomena and that the mix of radiation-induced features formed and the corresponding property degradation depend on a wide range of material and irradiation variables. This inherently multiscale evolution emphasizes the importance of closely integrating models with high-resolution experimental characterization of the evolving radiation-damaged microstructure. Lastly, this article provides a review of recent models of the defect microstructure evolution in irradiated body-centered cubic materials, which provide good agreement with experimental measurements, and presents some outstanding challenges, which will require coordinated high-resolution characterization and modeling to resolve.

  20. Dielectric spectroscopy at the nanoscale by atomic force microscopy: A simple model linking materials properties and experimental response

    SciTech Connect

    Miccio, Luis A. Colmenero, Juan; Kummali, Mohammed M.; Alegría, Ángel; Schwartz, Gustavo A.

    2014-05-14

    The use of an atomic force microscope for studying molecular dynamics through dielectric spectroscopy with spatial resolution in the nanometer scale is a recently developed approach. However, difficulties in the quantitative connection of the obtained data and the material dielectric properties, namely, frequency dependent dielectric permittivity, have limited its application. In this work, we develop a simple electrical model based on physically meaningful parameters to connect the atomic force microscopy (AFM) based dielectric spectroscopy experimental results with the material dielectric properties. We have tested the accuracy of the model and analyzed the relevance of the forces arising from the electrical interaction with the AFM probe cantilever. In this way, by using this model, it is now possible to obtain quantitative information of the local dielectric material properties in a broad frequency range. Furthermore, it is also possible to determine the experimental setup providing the best sensitivity in the detected signal.

  1. Computational and Experimental Study of Energetic Materials in a Counterflow Microgravity Environment

    NASA Technical Reports Server (NTRS)

    Takahashi, Fumiaki (Technical Monitor); Urban, David (Technical Monitor); Smooke, M. D.; Parr, T. P.; Hanson-Parr, D. M.; Yetter, R. A.; Risha, G.

    2004-01-01

    Counterflow diffusion flames are studied for various fuels flowing against decomposition products from solid ammonium perchlorate (AP) pellets in order to obtain fundamental understanding of composite propellant flame structure and chemistry. We illustrate this approach through a combined experimental and numerical study of a fuel mixture consisting of C2H4 CO + H2, and C2H2 + C2H4 flowing against solid AP. For these particular AP-fuel systems, the resulting flame zone simulates the various flame structures that are ex+ to exist between reaction products from Ap crystals and a hydrocarbon binder. As in all our experimental studies, quantitative species and temperature profiles have been measured between the fuel exit and AP surface. Species measured included CN, NH, NO, OH, N2, CO2, CO, H2, CO, HCl, and H2O. Temperature was measured using a thermocouple at the exit, spontaneous Raman scattering measurements throughout the flame, OH rotational population distributions, and NO vibrational population distributions. The burning rate of AP was also measured as a function of strain rate, given by the separation distance between the AP surface and the gaseous hydrocarbon fuel tube exit plane. This distance was nominally set at 5 mm, although studies have been performed for variations in separation distance. The measured 12 scalars are compared with predictions from a detailed gas-phase kinetics model consisting of 86 species and 531 reactions. Model predictions are found to be in good agreement with experiment and illustrate the type of kinetic features that may be expected to occur in propellants when AP particle size distributions are varied. Furthermore, the results constitute the continued development of a necessary database and validation of a comprehensive model for studying more complex AP-solid fuel systems in microgravity. Exploratory studies have also been performed with liquid and solid fuels at normal gravity. Because of melting (and hence dripping) and deep

  2. 34 CFR 98.3 - Access to instructional material used in a research or experimentation program.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... experimentation program. 98.3 Section 98.3 Education Office of the Secretary, Department of Education STUDENT... research or experimentation program. (a) All instructional material—including teachers' manuals, films, tapes, or other supplementary instructional material—which will be used in connection with any...

  3. How People Actually Use Thermostats

    SciTech Connect

    Meier, Alan; Aragon, Cecilia; Hurwitz, Becky; Mujumdar, Dhawal; Peffer, Therese; Perry, Daniel; Pritoni, Marco

    2010-08-15

    Residential thermostats have been a key element in controlling heating and cooling systems for over sixty years. However, today's modern programmable thermostats (PTs) are complicated and difficult for users to understand, leading to errors in operation and wasted energy. Four separate tests of usability were conducted in preparation for a larger study. These tests included personal interviews, an on-line survey, photographing actual thermostat settings, and measurements of ability to accomplish four tasks related to effective use of a PT. The interviews revealed that many occupants used the PT as an on-off switch and most demonstrated little knowledge of how to operate it. The on-line survey found that 89% of the respondents rarely or never used the PT to set a weekday or weekend program. The photographic survey (in low income homes) found that only 30% of the PTs were actually programmed. In the usability test, we found that we could quantify the difference in usability of two PTs as measured in time to accomplish tasks. Users accomplished the tasks in consistently shorter times with the touchscreen unit than with buttons. None of these studies are representative of the entire population of users but, together, they illustrate the importance of improving user interfaces in PTs.

  4. Studies on the dissolution of polycyclic aromatic hydrocarbons from contaminated materials using a novel dialysis tubing experimental method

    SciTech Connect

    Woolgar, P.J. Scottish Environment Protection Agency, Stirling ); Jones, K.C. )

    1999-06-15

    Assessment of risk and remediation strategies at contaminated sites requires that both the amounts of contaminants present and their potential for release from materials and soils be evaluated. The release, or dissolution, of polycyclic aromatic hydrocarbons (PAHs) from contaminated materials to water was therefore investigated. To facilitate investigations of PAH dissolution from physically disparate materials such as solid coal tars, creosote, oil, and spent oxide, an experimental method for measuring dissolved PAHs was developed employing dialysis tubing in batch-type system. This was validated and compared to aqueous-phase PAH concentrations measured using more traditional techniques and also predicted using Raoult's law. The experimental procedure was successfully used to determine near equilibrium aqueous concentrations of PAHs, but it could only be used to determine relative rates of approach to equilibrium as the dialysis tubing effected the rate constants. It was found that the contaminant materials influenced dissolution, in particular the close to equilibrium concentrations. For materials chemically similar to PAHs, such as nonaqueous-phase liquids (NAPLs), the concentrations could be predicted using Raoult's law. For materials that were chemically dissimilar to PAHs, such as spent oxide, release was more thermodynamically favorable than for NAPLs.

  5. Rb-Sr, K-Ar and fission track ages for granites from Penang Island, West Malaysia: an interpretation model for Rb-Sr whole-rock and for actual and experimental mica data

    NASA Astrophysics Data System (ADS)

    Kwan, T. S.; Krähenbühl, R.; Jager, E.

    1992-09-01

    depend on the degree of hydrothermal overprint at different crustal levels. An increase of the reaction surface by grain size reduction influences Rb-Sr and K-Ar mica ages in similar ways, as has been demonstrated by experimental data.

  6. [Use of bioactive glass ceramic material Biociyal-11 - experimental substantiation for jaw bone defects replacement].

    PubMed

    Bezzubik, S D; Grechukha, A M

    2009-01-01

    Pequliarities of morphologic osseous reparation of jaw bone defects in 15 non-bred dogs after implantation of different forms of glass crystal material Biocital-11 and blood clot on 7, 14, 21, 30 and 180th day after operation were shown. High biocompatibility of the material Biocital-11 with expressed osseous conductive function was disclosed.

  7. Computational modeling to enhance NDE experimental assessment of high temperature corrosion damage of near surface furnace/reactor structural material

    NASA Astrophysics Data System (ADS)

    Alharbi, W.; Meegan, G. D.; Mishra, B.; Olson, D. L.

    2013-01-01

    This study reports on the use of finite element modeling, COMSOL, to investigate ultrasonic methods to detect early stages of corrosion where the indications are limited to much more subtle changes in material lattice conditions such as carburization or internal oxidation. These subtle defects do not include any cracking or pitting but, rather, are characterized by a relatively slight change in material density and elasticity. The propagation and scattering of ultrasonic guided waves in a 2-D geometry was modeled to study the signal produced by near surface second phase growth from high temperature chemical reactions in reactor/furnace structural materials. The simulation results indicate that it is indeed possible to detect these types of subtle defects using a guided wave approach. The modeling is used to allow for better experimental design to achieve NDE data of mechanistic interpretation of the microstructure-mechanical behavior of reactor/furnace material during service.

  8. Experimental study of compatibility of reduced metal oxides with thermal energy storage lining materials

    NASA Astrophysics Data System (ADS)

    El-Leathy, Abdelrahman; Danish, Syed Noman; Al-Ansary, Hany; Jeter, Sheldon; Al-Suhaibani, Zeyad

    2016-05-01

    Solid particles have been shown to be able to operate at temperatures higher than 1000 °C in concentrated solar power (CSP) systems with thermal energy storage (TES). Thermochemical energy storage (TCES) using metal oxides have also found to be advantageous over sensible and latent heat storage concepts. This paper investigates the compatibility of the inner lining material of a TES tank with the reduced metal oxide. Two candidate metal oxides are investigated against six candidate lining materials. XRD results for both the materials are investigated and compared before and after the reduction of metal oxide at 1000°C in the presence of lining material. It is found that the lining material rich in zirconia is suitable for such application. Silicon Carbide is also found non-reacting with one of the metal oxides so it needs to be further investigated with other candidate metal oxides.

  9. Three-Dimensional Thermomechanical Simulation and Experimental Validation on Failure of Dissimilar Material Welds

    NASA Astrophysics Data System (ADS)

    Santosh, R.; Das, S. K.; Das, G.; Korody, J.; Kumar, S.; Singh, P. K.; Ghosh, M.

    2016-07-01

    Dissimilar material weld joints, consisting of low-alloy steel and 304LN austenitic stainless steel (SS), have critical application in boiling water reactors in the nuclear industry. It was predicted that phase transformation adjacent to the fusion boundary and stress distribution across the transition joint play a key role in the structural degeneration of these welds. Quantitatively, to evaluate their contribution, two different joints were considered. One was fabricated with buttering material 309L SS (M/S Mishra Dhatu Nigam Limited, Hyderabad, India), and the other was produced with buttering material IN182 (M/S Mishra Dhatu Nigam Limited, Hyderabad, India). Base materials remained the same for both. Thermomechanical simulation on dissimilar material welds was performed using finite-element modeling to predict the thermal effect and stress prone area. Temperature-dependent thermal and structural properties were considered for simulation. Simulation results were compared with microstructural characteristics, and data were obtained from the in-situ tensile test. Simulation results exhibited that stress was at maximum in the buttering material and made the zone weaker with respect to adjacent areas. During the validation of results, it was observed that failure occurred through buttering material and endorsed the inference. The variation in mechanical properties of the two welds was explained considering the effect of thermal state and stress distribution.

  10. The MIRTE Experimental Program: An Opportunity to Test Structural Materials in Various Configurations in Thermal Energy Spectrum

    SciTech Connect

    Leclaire, Nicolas; Le Dauphin, Francois-Xavier; Duhamel, Isabelle; Briggs, Blair; Piot, Jerome; Rennesson, Malvina; Laville, Arnaud

    2014-11-04

    The MIRTE (Materials in Interacting and Reflecting configurations, all Thicknesses) program was established to answer the needs of criticality safety practitioners in terms of experimental validation of structural materials and to possibly contribute to nuclear data improvement, which ultimately supports reactor safety analysis as well. MIRTE took the shape of a collaboration between the AREVA and ANDRA French industrialists and a noncommercial international funding partner such as the U.S. Department of Energy. The aim of this paper is to present the configurations of the MIRTE 1 and MIRTE 2 programs and to highlight the results of the titanium experiments recently published in the International Handbook of Evaluated Criticality Safety Benchmark Experiments.

  11. The numerical and experimental study on the compression and transfer molding of rubber materials

    NASA Astrophysics Data System (ADS)

    Han, S.; Jin, X.; Costa, F.; Melnikov, A.

    2014-05-01

    In this paper, a numerical study of compression and transfer molding of rubber materials will be presented. A three dimensional analysis is used for the numerical study. The program developed can predict the flow pattern, temperature, degree of cure, stresses within a part and press force change during filling and post-filling. Of particular interest is the change of stresses within a part and press force during post-filling due to thermal expansion of a material and the degree of cure. PVT, viscosity and curing kinetics data of one the rubber material are used for the calculation of pressure during filling and post-filling.

  12. A finite element model for wave propagation in an inhomogeneous material including experimental validation

    NASA Technical Reports Server (NTRS)

    Baumeister, Kenneth J.; Dahl, Milo D.

    1987-01-01

    A finite element model was developed to solve for the acoustic pressure field in a nonhomogeneous region. The derivations from the governing equations assumed that the material properties could vary with position resulting in a nonhomogeneous variable property two-dimensional wave equation. This eliminated the necessity of finding the boundary conditions between the different materials. For a two media region consisting of part air (in the duct) and part bulk absorber (in the wall), a model was used to describe the bulk absorber properties in two directions. An experiment to verify the numerical theory was conducted in a rectangular duct with no flow and absorbing material mounted on one wall. Changes in the sound field, consisting of planar waves was measured on the wall opposite the absorbing material. As a function of distance along the duct, fairly good agreement was found in the standing wave pattern upstream of the absorber and in the decay of pressure level opposite the absorber.

  13. [Experimental studies on the use of unwoven through-porous titanium material].

    PubMed

    Baĭrikov, I M; Amirov, R Sh; Baĭrikov, A I

    2013-01-01

    The paper describes titanium unwoven material with a through porosity (so called metal-rubber) designed for the manufacture of the intraosseous part of dental implants. Morphological processes occurring in and around the implants were studied in animal model.

  14. A finite element model for wave propagation in an inhomogeneous material including experimental validation

    NASA Technical Reports Server (NTRS)

    Baumeister, Kenneth J.; Dahl, Milo D.

    1987-01-01

    A finite element model was developed to solve for the acoustic pressure field in a nonhomogeneous region. The derivations from the governing equations assumed that the material properties could vary with position resulting in a nonhomogeneous variable property two-dimensional wave equation. This eliminated the necessity of finding the boundary conditions between the different materials. For a two media region consisting of part air (in the duct) and part bulk absorber (in the wall), a model was used to describe the bulk absorber properties in two directions. An experiment to verify the numerical theory was conducted in a rectangular duct with no flow and absorbing material mounted on one wall. Changes in the sound field, consisting of planar waves, was measured on the wall opposite the absorbing material. As a function of distance along the duct, fairly good agreement was found in the standing wave pattern upstream of the absorber and in the decay of pressure level opposite the absorber.

  15. Experimental characterization of magnetic materials for the magnetic shielding of cryomodules in particle accelerators

    DOE PAGES

    Sah, Sanjay; Myneni, Ganapati; Atulasimha, Jayasimha

    2015-10-26

    The magnetic properties of two important passive magnetic shielding materials (A4K and Amumetal) for accelerator applications, subjected to various processing and heat treatment conditions are studied comprehensively over a wide range of temperatures: from cryogenic to room temperature. Furthermore, we analyze the effect of processing on the extent of degradation of the magnetic properties of both materials and investigate the possibility of restoring these properties by re-annealing.

  16. High-temperature materials testing with full-field strain measurement: experimental design and practice.

    PubMed

    Novak, Mark D; Zok, Frank W

    2011-11-01

    Experimental characterization of the thermomechanical response of ceramic composites at very high temperatures is plagued by challenges associated with imaging and strain measurement. The problems involve illumination, heat haze, and surface contrast. Techniques that address these challenges have been developed and implemented in a laser heating facility, enabling non-contact strain measurement via digital image correlation. The thermomechanical characterization of both a Ni-based superalloy and a C/SiC composite are used to demonstrate the efficacy of experimental practices in realizing such measurements at temperatures up to 1500 °C. PMID:22129007

  17. 27 CFR 24.249 - Experimentation with new treating material or process.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., or be contrary to law, and has approved the application. (c) Segregation of operations. Experimentation authorized under this section will be conducted with the degree of segregation from wine... not jeopardize the revenue, conflict with wine operations, or be contrary to law. (b) Application....

  18. 27 CFR 24.249 - Experimentation with new treating material or process.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ..., or be contrary to law, and has approved the application. (c) Segregation of operations. Experimentation authorized under this section will be conducted with the degree of segregation from wine... not jeopardize the revenue, conflict with wine operations, or be contrary to law. (b) Application....

  19. (Fusion materials R D programs of the International Thermonuclear Experimental Reactor)

    SciTech Connect

    Reuther, T.C.

    1990-10-12

    The objective of this travel was to advance provisional planning of an activity to coordinate research and development (R D) activities on fusion materials among the existing fusion materials R D programs of the ITER parties. This objective was accomplished in discussions with the Executive Committee for the IEA Implementing Agreement on Fusion Materials in Karlsruhe, Germany, and with the ITER management and staff of Garching, Germany. The IEA Executive Committee deferred substantive consideration of the topic at the insistence of the Ex-Officio member from European Community (EC), Brussels. Discussions with ITER management and staff were positive. It was noted the the draft ITER Long-Term Technology Research and Development Plan contains recommendations for major program effort in materials R D and includes recommendations for coordination among the existing programs of the parties to meet those materials R D needs. ITER management discussions were in the context that decisions on specific activities for the ITER engineering design activity (EDA) must await formal action by the parties on the ITER EDA.

  20. 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.

  1. The utilization of Habrobracon and artemia as experimental materials in bioastronautic studies

    NASA Technical Reports Server (NTRS)

    Grosch, D. S.

    1972-01-01

    In the reproductive performance of female braconids striking contrasts were revealed between the results from the actual biosatellite flight and those from experiments when the recovered vehicle was subjected to the forces of simulated launching and recovery. Second week decreases in egg production due to the radiation damage of cells in mitosis were minimized for the females irradiated during space flight. It was demonstrated that females irradiated for two days during orbital flight laid as many eggs during the second week as the unirradiated ground-based controls. After the 10th day their oviposition records exceeded control values. The hatchability of eggs deposited by Biosatellite II females was excellent. Explanations were sought for the space flight's cancellation of the characteristic radiation-induced decrease in egg production, and for the exceptionally good hatchability of eggs derived from most of the cell types in the irradiated ovarioles. Eggs from only two classes of cells showed enhanced embryonic lethality: those poised in meiotic metaphase during their mother's orbital flight, and those from oocytes beginning vitellogenesis.

  2. Experimental and Analytical Characterization of the Macromechanical Response for Triaxial Braided Composite Materials

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.

    2013-01-01

    Increasingly, carbon composite structures are being used in aerospace applications. Their highstrength, high-stiffness, and low-weight properties make them good candidates for replacing many aerospace structures currently made of aluminum or steel. Recently, many of the aircraft engine manufacturers have developed new commercial jet engines that will use composite fan cases. Instead of using traditional composite layup techniques, these new fan cases will use a triaxially braided pattern, which improves case performance. The impact characteristics of composite materials for jet engine fan case applications have been an important research topic because Federal regulations require that an engine case be able to contain a blade and blade fragments during an engine blade-out event. Once the impact characteristics of these triaxial braided materials become known, computer models can be developed to simulate a jet engine blade-out event, thus reducing cost and time in the development of these composite jet engine cases. The two main problems that have arisen in this area of research are that the properties for these materials have not been fully determined and computationally efficient computer models, which incorporate much of the microscale deformation and failure mechanisms, are not available. The research reported herein addresses some of the deficiencies present in previous research regarding these triaxial braided composite materials. The current research develops new techniques to accurately quantify the material properties of the triaxial braided composite materials. New test methods are developed for the polymer resin composite constituent and representative composite coupons. These methods expand previous research by using novel specimen designs along with using a noncontact measuring system that is also capable of identifying and quantifying many of the microscale failure mechanisms present in the materials. Finally, using the data gathered, a new hybrid

  3. Development of a versatile experimental setup for the evaluation of the photocatalytic properties of construction materials under realistic outdoor conditions.

    PubMed

    Suárez, S; Portela, R; Hernández-Alonso, M D; Sánchez, B

    2014-10-01

    The interest on outdoor photocatalytic materials is growing in the last years. Nevertheless, most of the experimental devices designed for the assessment of their performance operate at controlled laboratory conditions, i.e., pollutant concentration, temperature, UV irradiation, and water vapor contents, far from those of real outdoor environments. The aim of the present study was the design and development of an experimental device for the continuous test of photocatalytic outdoor materials under sun irradiation using real outdoor air as feed, with the concomitant fluctuation of pollutant concentration, temperature, and water vapor content. A three-port measurement system based on two UV-transparent chambers was designed and built. A test chamber contained the photoactive element and a reference chamber to place the substrate without the photoactive element were employed. The third sampling point, placed outdoors, allowed the characterization of the surrounding air, which feeds the test chambers. Temperature, relative humidity (RH), and UV-A irradiance were monitored at each sampling point with specific sensors. NO x concentration was measured by a chemiluminescence NO x analyzer. Three automatic valves allowed the consecutive analysis of the concentration at the three points at fixed time intervals. The reliability of the analytical system was demonstrated by comparing the NO x concentration data with those obtained at the nearest weather station to the experimental device location. The use of a chamber-based reaction system leads to an attenuation of NO x and atmospheric parameter profiles, but maintaining the general trends. The air characterization results showed the wide operating window under which the photoactive materials should work outdoors, depending on the traffic intensity and the season, which are reproduced inside the test chambers. The designed system allows the measurement of the photoactivity of outdoor materials or the comparison of several

  4. Optical transitions in Cd{sub x}Hg{sub 1-x}Te-based quantum wells and their analysis with account for the actual band structure of the material

    SciTech Connect

    Bazhenov, N. L. Shilyaev, A. V.; Mynbaev, K. D.; Zegrya, G. G.

    2012-06-15

    Quantum-confinement levels in a Cd{sub x}Hg{sub 1-x}Te-based rectangular quantum well are calculated in the framework of the four-band Kane model taking into account mixing between the states of electrons and three types of holes (heavy, light, and spin-split holes). Comparison of the calculation results with experimental data on the photoluminescence of Cd{sub x}Hg{sub 1-x}Te-based quantum wells suggests that optical transitions involving the conduction and light-hole bands are possibly observed in the spectra.

  5. Experimental petrology of lunar material: the nature of mascons, seas, and the lunar interior.

    PubMed

    O'hara, M J; Biggar, G M; Richardson, S W

    1970-01-30

    One-atmosphere melting data show that Apollo 11 samples are near cotectic. Melting relations at pressures up to 35 kilobars show that clinopyroxenite or amphibole peridotite are possible lunar interiors. Mascons cannot be eclogite; they may be ilmenite accumulate. Hot lunar surface material will boil off alkalis. PMID:17781513

  6. Numerical and experimental study of the weld joints formation in welding foam materials

    SciTech Connect

    Bezginov, Roman O. E-mail: rakrekt@mail.ru; Krektuleva, Raisa A. E-mail: rakrekt@mail.ru; Mishin, Mikhail A. E-mail: rakrekt@mail.ru; Cherepanov, Oleg I. Cherepanov, Roman O.

    2014-11-14

    A numerical analysis of fusion welding of steel- and aluminum-based foam materials is carried out. The schemes of the structured and stochastic pore distribution are considered. The research results were used to conduct the experiments which confirmed the reliability of the numerical calculations.

  7. Experimental petrology of lunar material: the nature of mascons, seas, and the lunar interior.

    PubMed

    O'hara, M J; Biggar, G M; Richardson, S W

    1970-01-30

    One-atmosphere melting data show that Apollo 11 samples are near cotectic. Melting relations at pressures up to 35 kilobars show that clinopyroxenite or amphibole peridotite are possible lunar interiors. Mascons cannot be eclogite; they may be ilmenite accumulate. Hot lunar surface material will boil off alkalis.

  8. Experimental and theoretical investigations of functionalized boron nitride as electrode materials for Li-ion batteries

    SciTech Connect

    Zhang, Fan; Nemeth, Karoly; Bareño, Javier; Dogan, Fulya; Bloom, Ira D.; Shaw, Leon L.

    2016-01-01

    The feasibility of synthesizing functionalized h-BN (FBN) via the reaction between molten LiOH and solid h-BN is studied for the first time and its first ever application as an electrode material in Li-ion batteries is evaluated. Density functional theory (DFT) calculations are performed to provide mechanistic understanding of the possible electrochemical reactions derived from the FBN. Various materials characterizations reveal that the melt-solid reaction can lead to exfoliation and functionalization of h-BN simultaneously, while electrochemical analysis proves that the FBN can reversibly store charges through surface redox reactions with good cycle stability and coulombic efficiency. DFT calculations have provided physical insights into the observed electrochemical properties derived from the FBN.

  9. Incorporating waste into an experimental school prototype: lessons regarding materials reclamation opportunities.

    PubMed

    Yeap, Kong Seng; Mohd Yaacob, Naziaty; Rao, Sreenivasaiah Purushothama; Hashim, Nor Rasidah

    2012-12-01

    This article presents lessons learned from a design project that explored the possibility of incorporating waste into the design of a school prototype. The authors worked with professional architects, a waste artist, environmental scientists and local waste operators to uncover new uses and applications for discarded items. As a result, bottles, aluminium cans, reclaimed doors, crushed concrete and second-hand bricks, etc. were identified, explored and integrated into the architectural design. This article serves as a catalyst that advocates the use of reclaimed materials in the field of design and planning. In particular, it highlights the challenges and issues that need to be addressed in carrying out design work with waste. Designers and practitioners interested in minimizing waste generation by proposing the use of reclaimed materials will find this article useful. PMID:23103414

  10. Materials design concepts for efficient blue OLEDs: A joint theoretical and experimental study

    SciTech Connect

    Polikarpov, Evgueni; Padmaperuma, Asanga B.

    2012-04-01

    Since their discovery, organic light emitting devices have evolved from a scientific curiosity into a technology with applications in flat panel displays and the potential to revolutionize the lighting market. During their relatively short history, the technology incorporated into OLEDs has rapidly advanced. Device quantum efficiencies have increased more than 20-fold since the first OLEDs, approaching the theoretical limit for internal quantum efficiencies. , , At this point, OLED research moves towards optimization of manufacturing processes, drive circuitry, light extraction, and overall cost reduction. However, finding the organic materials that provide both operational stability and high efficiency for the devices still remains one of the biggest challenges, particularly for blue emission. In this presentation, we will describe our approach to design functional OLED materials to meet the complex criteria set forth by device efficiency and stability goals.

  11. Experimental Study of the Influence of Gassing Material on Blow Open Force and Arc Motion

    NASA Astrophysics Data System (ADS)

    Li, Xingwen; Chen, Degui; Liu, Hongwu; Shi, Zongqian; Wang, Jianhua

    2007-12-01

    The study of arc behavior is important to understand the dynamic phenomena concerning the interruption process in a variety of switching devices. This paper is devoted to investigate the influence of gassing material on blow open force and arc motion. To one double-breaker model, measuring the arc current, voltage and force acting on the moving conductor, the characteristics of the ratio of the emerging blow open force over arc power FB/(ui) could be obtained. With the help of a 2-D optical fiber measurement system, to one arc chamber model, arc motion behavior was measured, too. It is demonstrated that, with the action of gassing material, FB/(ui) will increase 2.5 times, and the arc will enter the splitter plates much easier.

  12. Incorporating waste into an experimental school prototype: lessons regarding materials reclamation opportunities.

    PubMed

    Yeap, Kong Seng; Mohd Yaacob, Naziaty; Rao, Sreenivasaiah Purushothama; Hashim, Nor Rasidah

    2012-12-01

    This article presents lessons learned from a design project that explored the possibility of incorporating waste into the design of a school prototype. The authors worked with professional architects, a waste artist, environmental scientists and local waste operators to uncover new uses and applications for discarded items. As a result, bottles, aluminium cans, reclaimed doors, crushed concrete and second-hand bricks, etc. were identified, explored and integrated into the architectural design. This article serves as a catalyst that advocates the use of reclaimed materials in the field of design and planning. In particular, it highlights the challenges and issues that need to be addressed in carrying out design work with waste. Designers and practitioners interested in minimizing waste generation by proposing the use of reclaimed materials will find this article useful.

  13. An experimental study on fatigue performance of cryogenic metallic materials for IMO type B tank

    NASA Astrophysics Data System (ADS)

    Lee, Jin-Sung; You, Won-Hyo; Yoo, Chang-Hyuk; Kim, Kyung-Su; Kim, Yooil

    2013-12-01

    Three materials SUS304, 9% Ni steel and Al 5083-O alloy, which are considered possible candidate for International Maritime Organization (IMO) type B Cargo Containment System, were studied. Monotonic tensile, fatigue, fatigue crack growth rate and Crack Tip Opening Displacement tests were carried out at room, intermediate low (-100 °C) and cryogenic (-163 °C) temperatures. The initial yield and tensile strengths of all materials tended to increase with decreasing temperature, whereas the change in elastic modulus was not as remarkable. The largest and smallest improvement ratio of the initial yield strengths due to a temperature reduction were observed in the SUS304 and Al 5083- O alloy, respectively. The fatigue strengths of the three materials increased with decreasing temperature. The largest increase in fatigue strength was observed in the Al 5083-O alloy, whereas the 9% Ni steel sample showed the smallest increase. In the fatigue crack growth rate test, SUS304 and Al 5083-O alloy showed a decrease in the crack propagation rate, due to decrease in temperature, but no visible improvement in da/dN was observed in the case of 9% Ni steel. In the Crack Tip Opening Displacement (CTOD) test, CTOD values were converted to critical crack length for the comparison with different thickness specimens. The critical crack length tended to decrease in the case of SUS304 and increase for the Al 5083-O alloy with decreasing temperature. In case of 9% Ni steel, change of critical crack length was not observed due to temperature decrease. In addition, the changing material properties according to the temperature of the LNG tank were analyzed according to the international code for the construction and equipment of ships carrying liquefied gases in bulk (IGC code) and the rules of classifications.

  14. Development of experimental setup for study of adsorption characteristics of porous materials down to 4.2 K

    NASA Astrophysics Data System (ADS)

    Behera, Upendra; Kasthurirengan, Srinivasan; Krishnamoorthy, V.; Senthil Kumar, A.; Kuzhiveli, Biju T.; Gangradey, Ranjana

    2012-06-01

    The knowledge of adsorption characteristics of activated carbon (porous material) in the temperature range from 5 to 20 K is essential when used in cryosorption pumps for nuclear fusion applications. However, such experimental data are very scarce in the literature, especially below 77 K. So, an experimental system is designed and fabricated to measure the adsorption characteristics of porous materials under variable cryogenic temperatures (from 5 K to 100 K). This is based on the commercially available micropore-analyser coupled to a closed helium cycle two-stage Gifford McMahon (GM) Cryocooler, which allows the sample to be cooled to 4.2 K. The sample port is coupled to the Cryocooler through a heat switch, which isolates this port from the cold head of the Cryocooler. By this, the sample temperature can now be varied without affecting the Cryocooler. The setup enables adsorption studies in the pressure range from atmospheric down to 10-4 Pa. The paper describes the details of the experimental setup and presents the results of adsorption studies at 77 K for activated carbon with nitrogen as adsorbate. The system integration is now completed to enable adsorption studies at 4.2 K.

  15. Transfer matrix modeling and experimental validation of cellular porous material with resonant inclusions.

    PubMed

    Doutres, Olivier; Atalla, Noureddine; Osman, Haisam

    2015-06-01

    Porous materials are widely used for improving sound absorption and sound transmission loss of vibrating structures. However, their efficiency is limited to medium and high frequencies of sound. A solution for improving their low frequency behavior while keeping an acceptable thickness is to embed resonant structures such as Helmholtz resonators (HRs). This work investigates the absorption and transmission acoustic performances of a cellular porous material with a two-dimensional periodic arrangement of HR inclusions. A low frequency model of a resonant periodic unit cell based on the parallel transfer matrix method is presented. The model is validated by comparison with impedance tube measurements and simulations based on both the finite element method and a homogenization based model. At the HR resonance frequency (i) the transmission loss is greatly improved and (ii) the sound absorption of the foam can be either decreased or improved depending on the HR tuning frequency and on the thickness and properties of the host foam. Finally, the diffuse field sound absorption and diffuse field sound transmission loss performance of a 2.6 m(2) resonant cellular material are measured. It is shown that the improvements observed at the Helmholtz resonant frequency on a single cell are confirmed at a larger scale. PMID:26093437

  16. Transfer matrix modeling and experimental validation of cellular porous material with resonant inclusions.

    PubMed

    Doutres, Olivier; Atalla, Noureddine; Osman, Haisam

    2015-06-01

    Porous materials are widely used for improving sound absorption and sound transmission loss of vibrating structures. However, their efficiency is limited to medium and high frequencies of sound. A solution for improving their low frequency behavior while keeping an acceptable thickness is to embed resonant structures such as Helmholtz resonators (HRs). This work investigates the absorption and transmission acoustic performances of a cellular porous material with a two-dimensional periodic arrangement of HR inclusions. A low frequency model of a resonant periodic unit cell based on the parallel transfer matrix method is presented. The model is validated by comparison with impedance tube measurements and simulations based on both the finite element method and a homogenization based model. At the HR resonance frequency (i) the transmission loss is greatly improved and (ii) the sound absorption of the foam can be either decreased or improved depending on the HR tuning frequency and on the thickness and properties of the host foam. Finally, the diffuse field sound absorption and diffuse field sound transmission loss performance of a 2.6 m(2) resonant cellular material are measured. It is shown that the improvements observed at the Helmholtz resonant frequency on a single cell are confirmed at a larger scale.

  17. Experimental study of a vortex ring impacting a smart material-based cantilevered plate

    NASA Astrophysics Data System (ADS)

    Peterson, Sean; Porfiri, Maurizio

    2011-11-01

    Recent developments in lightweight smart materials have generated scientific and technological advancements in small scale energy harvesting for powering low-consumption electronic devices. Often, energy is harvested from base excitation of a cantilevered smart material strip. In this case, the encompassing fluid acts as a passive damper, reducing the vibration amplitude and frequency, which reduces the harvesting capacity. By comparison, relatively few research efforts to date have explored the feasibility of using smart materials for harvesting energy directly from fluid motion. In this paper we employ vortex rings as the source from which to extract energy and use an ionic polymer metal composite (IPMC) strip in a cantilevered configuration as the harvesting device. Vortex rings, generated using a piston/cylinder arrangement submersed in water, are fired at the IPMC harvester and the resulting impact is recorded using a high speed video camera. The vortex ring propagation and circulation are estimated using flow visualization and particle image velocimetry. The plate deflection and electrical output are recorded as functions of time and correlated to the vortex strength and geometry.

  18. Superconductivity in Italian Secondary Schools: the experimentation carried out by Udine University with Supercomet2 (SC2) materials

    NASA Astrophysics Data System (ADS)

    Michelini, Marisa; Santi, Lorenzo; Viola, Rossana; Corni, Federico

    2008-05-01

    Through a highly interactive tools on CD, which comprises animation and films of demonstrative experiments, and uses modern pedagogical methods, such as collaborative learning and problem solving, the Supercomet 2 Project (SUPERCOnductivity Multimedia Educational Tool phase 2 of the European Union) aims to introduce superconductivity to European high school curriculums. During the first year of the project the following were produced: a CD-ROM with didactic material, a teacher's guide to clarify characteristics and roles of support material (texts, worksheets and computer presentations) and preview didactic courses. During the second year of the project It was: translated the material into the languages of countries participating in the project, experimented the application in high school classes in various parts of Europe, tested the updating course and the teacher's guide with a group of reference teachers. At the end of the first period of experimentation and dissemination were revised and new material was integrated in order to produce a final version at the end of the project. Further integrated proposals have been included with the revised material. In this paper the main characteristics realized during the project will be described.

  19. Experimental determination of ablation vapor species from carbon phenolic heat-shield materials

    NASA Technical Reports Server (NTRS)

    Lincoln, K. A.

    1981-01-01

    The relative concentrations of vapors produced from carbon phenolic composites under thermal loadings approximating those expected at peak heating during vehicle entry into the atmospheres of the outer planets have been determined. The technique of vaporizing the surface of bulk samples by laser irradiation while measuring in situ the vapor species by mass spectrometry is described. Results show that vapor composition varies with irradiance level and with depth of heating (or extent of pyrolysis). Attempts are made to compare these experimental results with the theoretical predictions from computer codes.

  20. Oxygen extraction from lunar materials - An experimental test of an ilmenite reduction process

    NASA Technical Reports Server (NTRS)

    Williams, R. J.

    1985-01-01

    The reaction of ilmenite with hydrogen to produce water has been studied experimentally in order to evaluate the effectiveness of using a cold trap to improve yields in a continuous flow process. Yields were enhanced, but not to the degree observed in batch processing systems. The terrestrial simulant used in these studies contained traces of iron sulfide, which released H2S during processing with a deleterious effect on several components of the test system. More sophisticated testing should be undertaken to obtain kinetic data and attention given to the removal of sulfides in the pre-process beneficiation.

  1. Experimental performance of a microwave electrothermal thruster with high temperature nozzle materials

    SciTech Connect

    Whitehair, S.; Frasch, L.L.; Asmussen, J.

    1987-05-01

    Testing of various modifications of a microwave electrothermal thruster, including the use of boron nitride and metal nozzles, the cooling of the nozzle with the incoming propellant, and the use of a spherical dome discharge chamber, is discussed. Tests were performed in nitrogen and helium gases over a 500-5000-sccm flow range and at pressures of up to 1500 torr, and experimental results are presented for specific impulse and energy efficiency. For the nitrogen experiments, excellant results were found for metal nozzle thrusters at very low flow rates in comparison with previous results for quartz nozzles at higher flow rates, and nozzle melting and erosion problems were eliminated. 11 references.

  2. Experimental study on the influence of foam porosity and pore size on the melting of phase change materials

    NASA Astrophysics Data System (ADS)

    Lafdi, K.; Mesalhy, O.; Shaikh, S.

    2007-10-01

    Experimental study was carried out to study the phase change heat transfer within a composite of phase change material (PCM) infiltrated high thermal conductivity foam. An experimental setup was built to measure the temperature profiles and capture the melting evolution of the PCM inside aluminum foams. Aluminum foams were used as the porous material, and low melting temperature paraffin wax was used as the PCM. It was observed from the results that the system parameters of the wax/foam composite had a significant influence on its heat transfer behavior. By using higher porosity aluminum foam, the steady-state temperature was reached faster as compared to the foams with lower porosity. Similarly for the bigger pore size foams the steady state was attained faster as compared to the smaller pore size foams. This was due to the greater effect of convection in both the higher porosity and bigger pore size foams. However, for the lower porosity foams the heater temperature was comparatively lower than the higher porosity foams due to greater heat conduction through the foam material. Therefore, an optimal value should be selected for the foam porosity and pore size such that the effects of both conduction and convection heat transfers can be completely utilized to have a greater and improved thermal performance for the wax/aluminum foam composite.

  3. A comparison of tissue reaction to MTA and an experimental root-end restorative material in rats.

    PubMed

    Modaresi, Jalil; Yavari, S Amir Saeid; Dianat, S Omid; Shahrabi, Shokufeh

    2005-08-01

    The purpose of this study was to compare the biocompatibility of a new experimental root-end filling material, "Cold Ceramic" (CC), with mineral trioxide aggregate (MTA) in rats. After anaesthetising 10 rats and raising tissue flaps, tablets of the material were placed subcutaneously. Five rats were followed for seven days and five for 30 days. An incision without any implanted material was used as a control. Histological analyses were performed with regard to number, type and location of the inflammatory cells and type of surrounding tissue. Kruskal-Wallis and Mann-Whitney statistical tests were used. Comparing inflammatory reactions between the two experimental groups (MTA and CC) and the control group showed significant differences after seven days (p = 0.031). There were no significant differences between CC and MTA groups after seven days (p = 0.222) and after 30 days (p = 0.063). The results suggested that MTA and CC are both biocompatible. It appears that MTA induces less inflammatory response in short periods of observation, but CC may be more biocompatible for slightly longer periods.

  4. Experimental Techniques for Evaluating the Effects of Aging on Impact and High Strain Rate Properties of Triaxial Braided Composite Materials

    NASA Technical Reports Server (NTRS)

    Pereira, J. Michael; Roberts, Gary D.; Ruggeri, Charles R.; Gilat, Amos; Matrka, Thomas

    2010-01-01

    An experimental program is underway to measure the impact and high strain rate properties of triaxial braided composite materials and to quantify any degradation in properties as a result of thermal and hygroscopic aging typically encountered during service. Impact tests are being conducted on flat panels using a projectile designed to induce high rate deformation similar to that experienced in a jet engine fan case during a fan blade-out event. The tests are being conducted on as-fabricated panels and panels subjected to various numbers of aging cycles. High strain rate properties are being measured using a unique Hopkinson bar apparatus that has a larger diameter than conventional Hopkinson bars. This larger diameter is needed to measure representative material properties because of the large unit cell size of the materials examined in this work. In this paper the experimental techniques used for impact and high strain rate testing are described and some preliminary results are presented for both as-fabricated and aged composites.

  5. A perspective on thermal annealing of reactor pressure vessel materials from the viewpoint of experimental results

    SciTech Connect

    Iskander, S.K.; Sokolov, M.A.; Nanstad, R.K.

    1996-04-01

    It is believed that in the next decade or so, several nuclear reactor pressure vessels (RPVs) may exceed the reference temperature limits set by the pressurized thermal shock screening criteria. One of the options to mitigate the effects of irradiation on RPVs is to thermally anneal them to restore the toughness properties that have been degraded by neutron irradiation. This paper summarizes recent experimental results from work performed at the Oak Ridge National Laboratory to study the annealing response, or ``recovery`` of several irradiated RPV steels. The fracture toughness is one of the important properties used in the evaluation of the integrity of RPVs. Optimally, the fracture toughness is measured directly by fracture toughness specimens, such as compact tension or precracked Charpy specimens, but is often inferred from the results of Charpy V-notch impact specimens. The experimental results are compared to the predictions of models for embrittlement recovery which have been developed by Eason et al. Some of the issues in annealing that still need to be resolved are discussed.

  6. Experimental study of osteoinduction using a new material as a carrier for bone morphogenetic protein-2.

    PubMed

    Koyama, Noriaki; Okubo, Yasunori; Nakao, Kazumasa; Osawa, Kenji; Bessho, Kazuhisa

    2011-06-01

    We evaluated the usefulness of artificial collagen as a new carrier for recombinant human bone morphogenetic protein-2 (rhBMP-2) by comparing it with that of atelopeptide collagen, which is derived from porcine skin, and which we have previously shown to be useful for the induction of bone. rhBMP-2 5μg with either atelopeptide collagen 3mg or artificial collagen 3mg was implanted into the calf muscle of 10-week-old Wistar rats (n=3 in each group). Three rats were given artificial collagen alone and acted as controls (n=3). Radiographic evaluation, histological analysis, and biochemical examinations were made on day 21 after implantation. Soft radiographs (wavelength 10-0.10nm) showed opaque shadows in both groups. Histological analysis showed that new bone had formed in both experimental groups. Endochondral ossification was found at the outermost edge of the implanted collagen in the atelopeptide group. However, there was less ossification in the implanted collagen in the artificial collagen group. On biochemical examination, alkaline phosphatase activity and calcium concentrations in both experimental groups were higher than in the control group, and were higher in the atelopeptide group than in the artificial collagen group. Our results suggest that artificial collagen is useful as a carrier for rhBMP-2 designed to promote the formation of new bone. PMID:20554359

  7. Experimental studies of seal materials for potential use in a Los Medanos-type bedded salt repository

    SciTech Connect

    Wakeley, L.D.; Roy, D.M.; Grutzeck, M.W.

    1981-09-01

    This investigation is composed of the following three tasks: (1) materials selection and factors affecting longevity of seal materials; (2) experimental seal materials for shaft, tunnel, and room backfill incorporating rock from the Los Medanos area; and (3) effects of the curing environment on properties of seal materials. Cement-based materials have been studied as candidates for backfilling and sealing boreholes, shafts, tunnels, and rooms in potential repository environments, particularly in bedded salt. In these studies, potential seal materials were selected and subjected to preliminary tests. Then, geochemical factors which control longevity of repository-sealing materials were investigated. The subjects of investigations included: factors controlling the attainment of equilibrium, with time, of the plug components; and the rate of approach of the plug-component subsystem to a state of equilibrium within the total system. The effect of these factors upon changes in physical, mechanical and thermal properties of a seal system, and the consequent effectiveness of the seal in preventing transport of radwaste species are being determined. High values were obtained for compressive strengths of some concretes (> 35 MPa); these samples also had very low permeabilities to brine (10/sup -7/ or 10/sup -8/ darcy). Highest strengths were obtained from samples cast with dolostone and anhydrite aggregate. Apparently, a strong bond generally was formed between the grout and the various rocks, evidenced by breakage through aggregate particles in tests of compressive strength. An expansive grout mixture containing salt was evaluated in five curing conditions, including: solutions saturated with CaSO/sub 4/, and Ca(OH)/sub 2/; deionized water; naturally occurring brine; and humid air, all at 38/sup 0/C. Expansion due to extensive growth of ettringite occurred in the first three of these five environments.

  8. Interactions between Antibiotics and Graphene-Based Materials in Water: A Comparative Experimental and Theoretical Investigation.

    PubMed

    Zhang, Xuntong; Shen, Jiachun; Zhuo, Ning; Tian, Ziqi; Xu, Peiran; Yang, Zhen; Yang, Weiben

    2016-09-14

    Complex interactions between antibiotics and graphene-based materials determine both the adsorption performance of graphene-based materials and the transport behaviors of antibiotics in water. In this work, such interactions were investigated through adsorption experiments, instrumental analyses and theoretical DFT calculations. Three typical antibiotics (norfloxacin (NOR), sulfadiazine (SDZ) and tetracycline (TC)) and different graphene-based materials (divided into two groups: graphene oxides-based ones (GOs) and reduced GOs (RGOs)) were employed. Optimal adsorption pHs for NOR, SDZ, and TC are 6.2, 4.0, and 4.0, respectively. At corresponding optimal pHs, NOR favored RGOs (adsorption capability: ∼50 mg/g) while SDZ preferred GOs (∼17 mg/g); All adsorbents exhibited similar uptake of TC (∼70 mg/g). Similar amounts of edge carboxyls of both GOs and RGOs wielded electrostatic attraction with NOR and TC, but not with SDZ. According to DFT-calculated most-stable-conformations of antibiotics-adsorbents complexes, the intrinsic distinction between GOs and RGOs was the different amounts of sp(2) and sp(3) hybridization regions: π-π electron donor-acceptor effect of antibiotic-sp(2)/sp(3) and H-bonds of antibiotic-sp(3) coexisted. Binding energy (BE) of the former was larger for NOR; the latter interaction was stronger for SDZ; two species of TC at the optimal pH, i.e., TC(+) and TC(0), possessed larger BE with sp(3) and sp(2) regions, respectively. PMID:27548426

  9. Cryogenic loading of large volume presses for high-pressure experimentation and synthesis of novel materials

    SciTech Connect

    Lipp, M J; Evans, W J; Yoo, C S

    2005-01-21

    We present an efficient easily implemented method for loading cryogenic fluids in a large volume press. We specifically apply this method to the high-pressure synthesis of an extended solid derived from CO using a Paris-Edinburgh cell. This method employs cryogenic cooling of Bridgman type WC anvils well insulated from other press components, condensation of the load gas within a brass annulus surrounding the gasket between the Bridgman anvils. We demonstrate the viability of the described approach by synthesizing macroscopic amounts (several milligrams) of polymeric CO-derived material, which were recovered to ambient conditions after compression of pure CO to 5 GPa or above.

  10. Experimental Observations of a Left-Handed Material That Obeys Snell's Law

    NASA Astrophysics Data System (ADS)

    Houck, Andrew A.; Brock, Jeffrey B.; Chuang, Isaac L.

    2003-04-01

    We measure two-dimensional profiles of collimated microwave beams transmitted through compos­ite wire and split-ring resonator prisms. Prior experiments suggest these structures have a negative index of refraction, though these claims have been questioned. Our 2D measurements demonstrate that transmission obeys Snell's law with a negative index, confirming the refractive nature of this signal and refuting alternatives posed in the criticisms. In addition, we present preliminary evidence that a flat rectangular slab of this material can focus power from a point source.

  11. Experimental determination of the shipboard fire environment for simulated radioactive material packages

    SciTech Connect

    Koski, J.A.; Bobbe, J.G.; Arviso, M.

    1997-03-01

    A series of eight fire tests with simulated radioactive material shipping containers aboard the test ship Mayo Lykes, a break-bulk freighter, is described. The tests simulate three basic types of fires: engine room fires, cargo fires and open pool fires. Detailed results from the tests include temperatures, heat fluxes and air flows measured during the fires. The first examination of the results indicates that shipboard fires are not significantly different from fires encountered in land transport. 13 refs., 15 figs., 11 tabs.

  12. Large-Scale Experimental Study of a Phase Change Material: Shape Identification for the Solid-Liquid Interface

    NASA Astrophysics Data System (ADS)

    Kadri, Soumaya; Dhifaoui, Belgacem; Dutil, Yvan; Jabrallah, Sadok Ben; Rousse, Daniel R.

    2015-11-01

    This study describes the development of an experimental setup that tracks the evolution of the melting and freezing fronts of a Phase Change Material (PCM), in this case paraffin. The results obtained enable the examination of the shape and movement of the melting front of the PCM. Two modes of heat transfer were identified during the melting process: conduction when melting began and natural convection, which becomes dominant in the remainder of the cycle. Monitoring of the melt over time shows that the melt fraction, expressed as the ratio of the molten volume and solid volume, is proportional to the difference between the imposed temperature and the melting temperature. Experimental results confirm the linearity proposed by other researchers.

  13. A combined experimental-computational study on nitrogen doped Cu2O as the wide-spectrum absorption material

    NASA Astrophysics Data System (ADS)

    Ping, Zhang; Yurong, Zhou; Qingbo, Yan; Fengzhen, Liu; Jingwen, Li; Gangqiang, Dong

    2014-10-01

    Highly-oriented Cu2O thin films were prepared by low temperature thermal oxidation of evaporated Cu thin films. The films were doped with different doses of nitrogen by ion implantation. An absorption peak appears below the absorption edge in the absorption spectrum of highly nitrogen doped Cu2O. The effect of nitrogen doping on the crystal structure, electronic structure and optical properties of Cu2O were investigated systematically by first-principles calculations. The calculation results indicate that an intermediate energy band exists in the forbidden gap of highly nitrogen doped Cu2O. The electron transition from the valence band to the intermediate band is consistent with the absorption peak by experimental observation. Experimental and computational results indicate that nitrogen doped Cu2O could be a suitable absorbing material candidate for wide-spectrum detectors or intermediate band solar cells.

  14. Experimental Evaluation of Journal Bearing Stability and New Gas Bearing Material

    NASA Technical Reports Server (NTRS)

    Keith, Theo G., Jr.; Dimofte, Florin

    2001-01-01

    It has been estimated that the noise levels in aircraft engine transmissions can be reduced by as much as 10 dB through the use of journal bearings. The potential benefits of lower noise levels include reduced wear, longer gear life and enhanced comfort for passengers and crew. Based on this concept the journal-thrust wave bearing was analyzed and its performance was evaluated. Numerical codes, developed over the past 30 years by Dr. Dimofte, were used to predict the performance of the bearing. The wave bearing is a fluid film bearing and therefore was analyzed using the Reynolds pressure equation. The formulation includes turbulent flow concepts and possesses a viscosity-temperature correction. The centrifugal growth of the bearing diameter and the deformation of the bearing under gear loads were also incorporated into the code. An experimental rig was developed to test the journal-thrust wave bearing.

  15. Shock-implanted noble gases. II - Additional experimental studies and recognition in naturally shocked terrestrial materials

    NASA Technical Reports Server (NTRS)

    Bogard, Donald; Horz, Friedrich; Johnson, Pratt

    1989-01-01

    The process by which ambient gases can be implanted into silicates by shocks was investigated by analyzing the noble-gas content of several experimentally and naturally shocked silicate samples. The retentivity of shock-implanted gas during stepwise heating in the laboratory was defined in terms of two parameters, namely, the activation energy for diffusion and the extraction temperature at which 50 percent of the gas is released, both of which correlate with the shock pressure. The experiments indicate that, with increasing shock pressure, gas implantation occurs through an increasing production of microcracks/defects in the silicate lattice. The degree of annealing of these defects control the degree of diffusive loss of implanted gas.

  16. Computational Modeling and Experimental Characterization of Martensitic Transformations in Nicoal for Self-Sensing Materials

    NASA Technical Reports Server (NTRS)

    Wallace, T. A.; Yamakov, V. I.; Hochhalter, J. D.; Leser, W. P.; Warner, J. E.; Newman, J. A.; Purja Pun, G. P.; Mishin, Y.

    2015-01-01

    Fundamental changes to aero-vehicle management require the utilization of automated health monitoring of vehicle structural components. A novel method is the use of self-sensing materials, which contain embedded sensory particles (SP). SPs are micron-sized pieces of shape-memory alloy that undergo transformation when the local strain reaches a prescribed threshold. The transformation is a result of a spontaneous rearrangement of the atoms in the crystal lattice under intensified stress near damaged locations, generating acoustic waves of a specific spectrum that can be detected by a suitably placed sensor. The sensitivity of the method depends on the strength of the emitted signal and its propagation through the material. To study the transition behavior of the sensory particle inside a metal matrix under load, a simulation approach based on a coupled atomistic-continuum model is used. The simulation results indicate a strong dependence of the particle's pseudoelastic response on its crystallographic orientation with respect to the loading direction and suggest possible ways of optimizing particle sensitivity. The technology of embedded sensory particles will serve as the key element in an autonomous structural health monitoring system that will constantly monitor for damage initiation in service, which will enable quick detection of unforeseen damage initiation in real-time and during onground inspections.

  17. Experimental study on cryogenic moisture uptake in polyurethane foam insulation material

    NASA Astrophysics Data System (ADS)

    Zhang, X. B.; Yao, L.; Qiu, L. M.; Gan, Z. H.; Yang, R. P.; Ma, X. J.; Liu, Z. H.

    2012-12-01

    Rigid foam is widely used to insulate cryogenic tanks, in particular for space launch vehicles due to its lightweight, mechanical strength and thermal-insulating performance. Up to now, little information is available on the intrusion of moisture into the material under cryogenic conditions, which will bring substantial additional weight for the space vehicles at lift-off. A cryogenic moisture uptake apparatus has been designed and fabricated to measure the amount of water uptake into the polyurethane foam. One side of the specimen is exposed to an environment with high humidity and ambient temperature, while the other with cryogenic temperature at approximately 78 K. A total of 16 specimens were tested for up to 24 h to explore the effects of the surface thermal protection layer, the foam thickness, exposed time, the butt joints, and the material density on water uptake of the foam. The results are constructive for the applications of the foam to the cryogenic insulation system in space launch vehicles.

  18. Experimental study of the mechanical behaviour of pin reinforced foam core sandwich materials under shear load

    NASA Astrophysics Data System (ADS)

    Dimassi, M. A.; Brauner, C.; Herrmann, A. S.

    2016-03-01

    Sandwich structures with a lightweight closed cell hard foam core have the potential to be used in primary structures of commercial aircrafts. Compared to honeycomb core sandwich, the closed cell foam core sandwich overcomes the issue of moisture take up and makes the manufacturing of low priced and highly integrated structures possible. However, lightweight foam core sandwich materials are prone to failure by localised external loads like low velocity impacts. Invisible cracks could grow in the foam core and threaten the integrity of the structure. In order to enhance the out-of-plane properties of foam core sandwich structures and to improve the damage tolerance (DT) dry fibre bundles are inserted in the foam core. The pins are infused with resin and co-cured with the dry fabric face sheets in an out-of-autoclave process. This study presents the results obtained from shear tests following DIN 53294-standard, on flat sandwich panels. All panels were manufactured with pin-reinforcement manufactured with the Tied Foam Core Technology (TFC) developed by Airbus. The effects of pin material (CFRP and GFRP) and pin volume fraction on the shear properties of the sandwich structure and the crack propagation were investigated and compared to a not pinned reference. It has been concluded that the pin volume fraction has a remarkable effect on the shear properties and damage tolerance of the observed structure. Increasing the pin volume fraction makes the effect of crack redirection more obvious and conserves the integrity of the structure after crack occurrence.

  19. Experimental and Analytical Seismic Studies of a Four-Span Bridge System with Innovative Materials

    NASA Astrophysics Data System (ADS)

    Cruz Noguez, Carlos Alonso

    As part of a multi-university project utilizing the NSF Network for Earthquake Engineering Simulation (NEES), a quarter-scale model of a four-span bridge incorporating plastic hinges with different advanced materials was tested to failure on the three shake table system at the University of Nevada, Reno (UNR). The bridge was the second test model in a series of three 4-span bridges, with the first model being a conventional reinforced-concrete (RC) structure. The purpose of incorporating advanced materials was to improve the seismic performance of the bridge with respect to two damage indicators: (1) column damage and (2) permanent deformations. The goals of the study presented in this document were to (1) evaluate the seismic performance of a 4-span bridge system incorporating SMA/ECC and built-in rubber pad plastic hinges as well as post-tensioned piers, (2) quantify the relative merit of these advanced materials and details compared to each other and to conventional reinforced concrete plastic hinges, (3) determine the influence of abutment-superstructure interaction on the response, (4) examine the ability of available elaborate analytical modeling techniques to model the performance of advanced materials and details, and (5) conduct an extensive parametric study of different variations of the bridge model to study several important issues in bridge earthquake engineering. The bridge model included six columns, each pair of which utilized a different advanced detail at bottom plastic hinges: shape memory alloys (SMA), special engineered cementitious composites (ECC), elastomeric pads embedded into columns, and post-tensioning tendons. The design of the columns, location of the bents, and selection of the loading protocol were based on pre-test analyses conducted using computer program OpenSees. The bridge model was subjected to two-horizontal components of simulated earthquake records of the 1994 Northridge earthquake. Over 340 channels of data were collected

  20. Experimental Evidence Supported by Simulations of a Very High H{sub 2} Diffusion in Metal Organic Framework Materials

    SciTech Connect

    Salles, F.; Maurin, G.; Jobic, H.; Koza, M. M.; Llewellyn, P. L.; Devic, T.; Serre, C.; Ferey, G.

    2008-06-20

    Quasielastic neutron scattering measurements are combined with molecular dynamics simulations to extract the self-diffusion coefficient of hydrogen in the metal organic frameworks MIL-47(V) and MIL-53(Cr). We find that the diffusivity of hydrogen at low loading is about 2 orders of magnitude higher than in zeolites. Such a high mobility has never been experimentally observed before in any nanoporous materials, although it was predicted in carbon nanotubes. Either 1D or 3D diffusion mechanisms are elucidated depending on the chemical features of the MIL framework.

  1. Elastic characterization of isotropic materials by a single test based on the experimental determination of natural frequencies using laser interferometry

    SciTech Connect

    Bayon, A.; Varade, A.; Gascon, F.

    1997-04-01

    An experimental method is proposed for the elastic characterization of an isotropic material based upon the vibration natural frequencies recorded by means of a single assembly and experiment. Speckle heterodyne optic interferometry is applied to detect the tangential component of the vibration at a point. The sample is a slender rod excited through a broad-spectrum percussion, where the vibration recorded is a superposition of the transverse and torsional natural modes. Spectral analysis of the vibration allows the identification of the transverse and torsional natural frequencies. This is followed by calculation of the elastic moduli. {copyright} {ital 1997 Acoustical Society of America.}

  2. Modeling of the charge-state separation at ITEP experimental facility for material science based on a Bernas ion source.

    PubMed

    Barminova, H Y; Saratovskyh, M S

    2016-02-01

    The experiment automation system is supposed to be developed for experimental facility for material science at ITEP, based on a Bernas ion source. The program CAMFT is assumed to be involved into the program of the experiment automation. CAMFT is developed to simulate the intense charged particle bunch motion in the external magnetic fields with arbitrary geometry by means of the accurate solution of the particle motion equation. Program allows the consideration of the bunch intensity up to 10(10) ppb. Preliminary calculations are performed at ITEP supercomputer. The results of the simulation of the beam pre-acceleration and following turn in magnetic field are presented for different initial conditions.

  3. Determining the representative volume element size for three-dimensional microstructural material characterization. Part 2: Application to experimental data

    NASA Astrophysics Data System (ADS)

    Harris, William M.; Chiu, Wilson K. S.

    2015-05-01

    Improved microstructural imaging and characterization methods have recently opened the door for quantitative evaluation of microstructures of such functional materials as solid oxide fuel cell and battery electrodes and composite gas separation membranes. Accurate quantitative characterization of these structures relies on the concept of a representative volume element (RVE) to provide a sufficiently large sample to be statistically representative of the material. In Part 1 of this work, several models were described to determine the RVE size for several common microstructural properties: volume fraction, particle size, and network contiguity. In this work, extensive synchrotron X-ray nanotomography imaging of a multiphase composite gas separation membrane is used to provide an experimental comparison to the model predictions. Results suggest that the models provide a reasonable estimate of RVE size, and can serve as a starting point for researchers planning imaging and characterization experiments.

  4. Experimental and in silico investigations of organic phosphates and phosphonates sorption on polymer-ceramic monolithic materials and hydroxyapatite.

    PubMed

    Pietrzyńska, Monika; Zembrzuska, Joanna; Tomczak, Rafał; Mikołajczyk, Jakub; Rusińska-Roszak, Danuta; Voelkel, Adam; Buchwald, Tomasz; Jampílek, Josef; Lukáč, Miloš; Devínsky, Ferdinand

    2016-10-10

    A method based on experimental and in silico evaluations for investigating interactions of organic phosphates and phosphonates with hydroxyapatite was developed. This quick and easy method is used for determination of differences among organophosphorus compounds of various structures in their mineral binding affinities. Empirical sorption evaluation was carried out using liquid chromatography with tandem mass spectrometry or UV-VIS spectroscopy. Raman spectroscopy was used to confirm sorption of organic phosphates and phosphonates on hydroxyapatite. Polymer-ceramic monolithic material and bulk hydroxyapatite were applied as sorbent materials. Furthermore, a Polymer-ceramic Monolithic In-Needle Extraction device was used to investigate both sorption and desorption steps. Binding energies were computed from the fully optimised structures utilising Density Functional Theory (DFT) at B3LYP/6-31+G(d,p) level. Potential pharmacologic and toxic effects of the tested compounds were estimated by the Prediction of the Activity Spectra of Substances using GeneXplain software. PMID:27552905

  5. Experimental assessment of non-treated bentonite as the buffer material of a radioactive waste repository.

    PubMed

    Choi, J; Kang, C H; Whang, J

    2001-05-01

    The bentonite-based material being evaluated in several countries as potential barriers and seals for a nuclear waste disposal system is of mostly sodium type, whereas most bentonite available in Korea is known to be of calcium type. In order to investigate whether local Korean bentonite could be useful as a buffer or sealing material in an HLW repository system, raw bentonites sampled from the south-east area of Korea were examined in terms of their physicochemical properties such as surface area, CEC, swelling rate, and distribution coefficient. The diffusion behavior of some radionuclides of interest in compacted bentonite was also investigated. Considering that HLW generates decay heat over a long time, the thermal effect on the physicochemical properties of bentonite was also included. Four local samples were identified as Ca-bentonite through XRD and chemical analysis. Of the measured values of surface area, CEC and swelling rate of the local samples, Sample-A was found to have the greatest properties as the most likely candidate barrier material. The distribution coefficients of Cs-137, Sr-85, Co-60 and Am-241 for Sample-A sample were measured by the batch method. Sorption equilibrium was reached in around 8 to 10 days, but that of Sr was found to be reached earlier. Comparing the results of this study with the reference data, domestic bentonite was found to have a relatively high sorption ability. For the effect of varying concentration on sorption, the values of Kd peaked at 10(-9)-10(-7) mol/l of radionuclide concentration. In XRD analysis, the (001) peak of Sample-A was fully collapsed above 200 degrees C. The shoulder appearing at about 150 degrees C in the DSC curve was found to be evidence that Sample-A is predominated by Ca-montmorillonite. The loss of swelling capacity and CEC of Sample-A started at about 100 degrees C. The swelling data and the (001) peak intensity of the heat-treated sample showed that they were linearly interrelated. The measured

  6. Corrosion of turbine materials exposed to the effluent of an experimental PFBC

    SciTech Connect

    McCarron, R.L.; Brobst, R.P.

    1985-01-01

    The primary objective of this program is to determine the corrosion resistance of candidate gas turbine vane and blade base alloys and protective coating systems exposed to hot combustion gases at temperatures of 788 to 816/sup 0/C and velocities of 9 m/s. The corrosion resistance of various materials were evaluated at three metal temperatures: 788 to 816/sup 0/C uncooled and 593 and 704/sup 0/C using air-cooled hollow pins. Results indicate that unprotected nickel and cobalt base gas turbine blade and vane alloys are susceptible to hot corrosion attack at all three metal temperatures. MCrAlY (M=Fe, Ni, Co) overlay coatings and aluminide diffusion coatings in general show good corrosion resistance at 816/sup 0/C, but exhibit susceptibility to pitting attack at metal temperatures in the range of 593 to 704/sup 0/C.

  7. Experimental characterization of biphasic materials using rate-controlled Hertzian indentation

    PubMed Central

    Moore, A.C.; Zimmerman, B.K.; Chen, X; Lu, X.L.; Burris, D.L.

    2015-01-01

    This paper describes a new method, based on Hertzian biphasic theory (HBT), to characterize properties of biphasic materials with reduced time demands, increased surface sensitivity, and reduced computational demands compared to the current gold standards. Indentation experiments were conducted at a single location on a representative osteochondral plug to demonstrate and validate the HBT method against two gold standards, linear biphasic theory (LBT) and tension-compression nonlinear biphasic theory (TCN). The 1) aggregate moduli, 2) permeability and 3) tensile moduli from HBT, LBT, and TCN were 1) HA=0.47, 0.47, and 0.40 MPa, 2) k=0.0026, 0.0014 and 0.0016mm4/Ns, and 3) Et=8.7, 0.46, and 10.3MPa, respectively. The results support the HBT method and encourage its use, especially in light of its practical advantages. PMID:26160994

  8. Combustion aerosols formed during burning of radioactively contaminated materials: Experimental results

    SciTech Connect

    Halverson, M.A.; Ballinger, M.Y.; Dennis, G.W.

    1987-03-01

    Safety assessments and environmental impact statements for nuclear fuel cycle facilities require an estimate of potential airborne releases. Radioactive aerosols generated by fires were investigated in experiments in which combustible solids and liquids were contaminated with radioactive materials and burned. Uranium in powder and liquid form was used to contaminate five fuel types: polychloroprene, polystyrene, polymethylmethacrylate, cellulose, and a mixture of 30% tributylphosphate (TBP) in kerosene. Heat flux, oxygen concentration, air flow, contaminant concentration, and type of ignition were varied in the experiments. The highest release (7.1 wt %) came from burning TBP/kerosene over contaminated nitric acid. Burning cellulose contaminated with uranyl nitrate hexahydrate liquid gave the lowest release (0.01 wt %). Rate of release and particle size distribution of airborne radioactive particles were highly dependent on the type of fuel burned.

  9. An experimental investigation of interfacial temperatures in blade-seal material rubbing of aircraft compressors

    NASA Technical Reports Server (NTRS)

    Emery, A. F.; Wolak, J.; Etemad, S.; Choi, S. R.

    1982-01-01

    Results are presented for the rubbing of rotating (100 m/s) titanium blade specimens, with different plasma-sprayed tip coating, against an abradable porous seal material at two different incursion rates. In general, there was a good correspondence between the average transverse force of rubbing and the seal specimen surface temperature. Instantaneous seal surface temperature measurement showed a significant temperature jump before and after each rubbing with a high rate of cooling during each revolution and a high overall temperature level. Numerical predictions of both blade and seal temperature agreed well for the bare blade tip experiments but were consistently high for the coated blades. This suggests that the thermal properties of the coatings may significantly affect the temperatures and hence the wear characteristics of the system.

  10. Experimental assessment of non-treated bentonite as the buffer material of a radioactive waste repository.

    PubMed

    Choi, J; Kang, C H; Whang, J

    2001-05-01

    The bentonite-based material being evaluated in several countries as potential barriers and seals for a nuclear waste disposal system is of mostly sodium type, whereas most bentonite available in Korea is known to be of calcium type. In order to investigate whether local Korean bentonite could be useful as a buffer or sealing material in an HLW repository system, raw bentonites sampled from the south-east area of Korea were examined in terms of their physicochemical properties such as surface area, CEC, swelling rate, and distribution coefficient. The diffusion behavior of some radionuclides of interest in compacted bentonite was also investigated. Considering that HLW generates decay heat over a long time, the thermal effect on the physicochemical properties of bentonite was also included. Four local samples were identified as Ca-bentonite through XRD and chemical analysis. Of the measured values of surface area, CEC and swelling rate of the local samples, Sample-A was found to have the greatest properties as the most likely candidate barrier material. The distribution coefficients of Cs-137, Sr-85, Co-60 and Am-241 for Sample-A sample were measured by the batch method. Sorption equilibrium was reached in around 8 to 10 days, but that of Sr was found to be reached earlier. Comparing the results of this study with the reference data, domestic bentonite was found to have a relatively high sorption ability. For the effect of varying concentration on sorption, the values of Kd peaked at 10(-9)-10(-7) mol/l of radionuclide concentration. In XRD analysis, the (001) peak of Sample-A was fully collapsed above 200 degrees C. The shoulder appearing at about 150 degrees C in the DSC curve was found to be evidence that Sample-A is predominated by Ca-montmorillonite. The loss of swelling capacity and CEC of Sample-A started at about 100 degrees C. The swelling data and the (001) peak intensity of the heat-treated sample showed that they were linearly interrelated. The measured

  11. Dynamicimagestoaddressconceptualnodes about mechanical waves: Example materials and preliminary results of the experimentation of the teacher training module IMAGONDE

    NASA Astrophysics Data System (ADS)

    Testa, I.; Lombardi, S.; Monroy, G.; Sassi, E.

    2004-09-01

    In the framework of the 2002-03 project “Fisica per la Formazione Culturale - FORMazione Insegnanti" funded by Italy ministry of Education, a set of training materials, focused on mechanical waves, has been developed. The core of the materials is represented by animated images purposely designed in order to: 1) address intrinsically dynamic aspects of one-dimensional impulses/waves propagation on a string; 2) have the trainees reflect upon students' difficulties in reading/interpreting static images (as the ones which are featured in common textbooks) and animations. In this paper we discuss example materials concerning transversal impulses on strings to address conceptual nodes such as: 1) configuration of the string at a given time and its aaabstract representation; 2) displacement vs. time graph of a string element and its aaabstract representation; 3) relationships between the two aaabstract representations; 4) modelization of mechanical wave propagation in one dimension. Moreover the results of the experimentation of the training materials in the framework of the Post Graduate School to Became Physics Teacher in Secondary Schools are presented and commented.

  12. Analytical and Experimental Studies of the Degradation in Hydrogenated Amorphous Silicon Solar Cells and Materials.

    NASA Astrophysics Data System (ADS)

    Yeung, Ping Fai

    1995-01-01

    An improved understanding of a-Si:H pin solar cells stability was obtained by studying light induced degradation in a-Si:H films and in devices. The current -voltage characteristics and the quantum efficiencies of a-Si:H pin solar cells were measured as a function of intrinsic layer thickness, bias light intensity and degradation condition. Photoconductivity measurements on device quality intrinsic a-Si:H thin film materials showed that the majority carrier (electron) mutau product degraded from 3times 10^{-7}rm cm ^2/V to 2times 10^{ -7}rm cm^2/V after 6 minutes of 50-Suns light illumination. Using a dual beam technique with steady white light and modulated monochromatic light, a degradation profile was detected in the degraded materials. These results suggest that inhomogeneous degradation may be important to understanding the stability of a-Si:H pin solar cells. An analytical model was developed for degradation in a-Si:H pin solar cells based on inhomogeneous degradation, which was used to explain the 'blue-dip' effect observed in the quantum efficiencies of degraded cells. A new method was developed to investigate the minority carrier (hole) diffusion length in device quality a-Si:H films as a function of degradation. This method uses the Schottky barrier structure to establish a depletion region, which can be controlled by the applied voltage and the bias light intensity. Modulated blue light is used to generate electron hole pairs near the ohmic contacts, and the holes diffuse across the neutral region to be collected. The modulated current is related to the diffusion length of the holes due to this current limiting hole transport. Comparing the results of this new technique to that of the Photocarrier Grating method, the electron drift mobility was found to degrade from rm 2.5cm^2/Vs to rm 0.15cm^2/Vs after 6 minutes of 50-Suns degradation.

  13. Solid Silicone Elastomer Material(DC745U)-Historical Overview and New Experimental Results

    SciTech Connect

    Ortiz-Acosta, Denisse

    2012-08-08

    DC745U is a silicone elastomer used in several weapon systems. DC745U is manufactured by Dow Corning and its formulation is proprietary. Risk changes without notification to the customer. {sup 1}H and {sup 29}Si{l_brace}{sup 1}H{r_brace} NMR have previously determined that DC745U contains {approx} 98.5% dimethyl siloxane, {approx}1.5% methyl-phenyl siloxane, and a small amount (<1%) of vinyl siloxane repeat units that are converted to crosslinking sites. The polymer is filled with {approx} 38 wt.% of a mixture of fumed silica and quartz. Some conclusions are: (1) DMA shows that crystallization does have an effect on the mechanical properties of DC745U; (2) DMA shows that the crystallization is time and temperature dependent; (3) Mechanical tests show that DC745U undergo a crystalline transition at temperatures below -50 C; (4) Rate and temperature does not have an effect above crystalline transition; (5) Crystalline transition occurs faster at colder temperatures; (6) The material remains responsive and recovers after warming it to temperature above -40 C; (7) We were able to review all previous historical data on DC745U; (8) Identified specific gaps in materials understanding; (9) Developed design of experiments and testing methods to address gaps associated with post-curing and low temperature mechanical behavior; (10) Resolved questions of post-cure and alleviated concerns associated with low temperature mechanical behavior with soak time and temperature; and (11) This work is relevant to mission-critical programs and for supporting programmatic work for weapon research.

  14. Experimental measurements of thermal properties of high-temperature refractory materials used for thermal energy storage

    NASA Astrophysics Data System (ADS)

    El-Leathy, Abdelrahman; Jeter, Sheldon; Al-Ansary, Hany; Abdel-Khalik, Said; Golob, Matthew; Danish, Syed Noman; Saeed, Rageh; Djajadiwinata, Eldwin; Al-Suhaibani, Zeyad

    2016-05-01

    This paper builds on studies conducted on thermal energy storage (TES) systems that were built as a part of the work performed for a DOE-funded SunShot project titled "High Temperature Falling Particle Receiver". In previous studies, two small-scale TES systems were constructed for measuring heat loss at high temperatures that are compatible with the falling particle receiver concept, both of which had shown very limited heat loss. Through the course of those studies, it became evident that there was a lack of information about the thermal performance of some of the insulating refractory materials used in the experiments at high temperatures, especially insulating firebrick and perlite concrete. This work focuses on determining the thermal conductivities of those materials at high temperatures. The apparatus consists of a prototype cylindrical TES bin built with the same wall construction used in previous studies. An electric heater is placed along the centerline of the bin, and thermocouples are used to measure temperature at the interfaces between all layers. Heat loss is measured across one of the layers whose thermal conductivity had already been well established using laboratory experiments. This value is used to deduce the thermal conductivity of other layers. Three interior temperature levels were considered; namely, 300°C, 500°C, and 700°C. Results show that the thermal conductivity of insulating firebrick remains low (approximately 0.22 W/m.K) at an average layer temperature as high as 640°C, but it was evident that the addition of mortar had an impact on its effective thermal conductivity. Results also show that the thermal conductivity of perlite concrete is very low, approximately 0.15 W/m.K at an average layer temperature of 360°C. This is evident by the large temperature drop that occurs across the perlite concrete layer. These results should be useful for future studies, especially those that focus on numerical modeling of TES bins.

  15. Computational and Experimental Study of Energetic Material in a Counterflow Microgravity Environment

    NASA Technical Reports Server (NTRS)

    Smooke, Mitchell D.; Yetter, R. A.; Parr, T. P.; Hanson-Parr, D. M.; Tanoff, M. A.

    1999-01-01

    Ground based (normal gravity) combustion studies can provide important information on the processes by which monopropellants and composite systems burn. The effects of gravitational forces, however, can often complicate the interpretation of the models and the implementation of experiments designed to help elucidate complex issues. We propose to utilize a combined computational/experimental approach in a microgravity environment to understand the interaction of oxidizer-binder diffusion flames in composite propellants. By operating under microgravity conditions we will be able to increase the length scales and suppress the gravitational forces on melting binders such that increased resolution of both major and minor species will be possible thus reducing the demands placed on both the computational and diagnostic tools. Results of a detailed transport/finite rate chemistry model will be compared with nonintrusive optical diagnostic measurements of the structure and extinction of diffusion flames in which oxidizers such as ammonium perchlorate (AP) and ammonium dinitramide (ADN) are counterflowed against realistic binders such as hydroxyl-terminated polybutadiene (HTPB) and 3,3-bis(azidomethyl)oxetane (BAMO). The work proposed herein represents a collaborative effort among the research groups at Yale University, Princeton University and the Combustion Diagnostics Laboratory at the Naval Air Warfare Center in China Lake, CA.

  16. Upgrade of X-ray Magnetic Diffraction Experimental System and Its Application to Ferromagnetic Material

    SciTech Connect

    Suzuki, Kosuke; Tsuji, Naruki; Akiyama, Hiromitu; Ito, Masahisa; Kitani, Kensuke; Adachi, Hiromichi; Kawata, Hiroshi

    2007-01-19

    We have performed X-ray magnetic diffraction (XMD) experiment of ferromagnets at the Photon Factory (PF) of the High Energy Accelerator Research Organization (KEK) in Tsukuba. In this study, we have upgraded the XMD experimental system in order to apply this method to as many samples as possible. Upgrade was made for (1) the X-ray counting system and related measurement program, (2) the electromagnet, and (3) the refrigerator. The performance of the system was enhanced so that (1) the counting rate capability was improved from 104cps to 105cps, (2) the maximum magnetic field was increased from 0.85T to 2.15T, and (3) the lowest sample temperature was reduced from 15K to 5K. The new system was applied to an orbital ordering compound of YTiO3, and we obtained spin magnetic form factor for the reflection plane (010) perpendicular to the b axis. The magnetic field of 2T was needed to saturate the magnetization of YTiO3 along the b axis. These are the first data with the magnetization of YTiO3 saturated along the b axis by the XMD.

  17. An experimental study of low velocity impacts into granular material in reduced gravity

    NASA Astrophysics Data System (ADS)

    Murdoch, Naomi; Avila Martinez, Iris; Sunday, Cecily; Cherrier, Olivier; Zenou, Emanuel; Janin, Tristan; Cadu, Alexandre; Gourinat, Yves; Mimoun, David

    2016-04-01

    The granular nature of asteroid surfaces, in combination with the low surface gravity, makes it difficult to predict lander - surface interactions from existing theoretical models. Nonetheless, an understanding of such interactions is particularly important for the deployment of a lander package. This was demonstrated by the Philae lander, which bounced before coming to rest roughly 1 kilometer away from its intended landing site on the surface of comet 67P/Churyumov-Gerasimenko before coming to rest (Biele et al., 2015). In addition to being important for planning the initial deployment, information about the acceleration profile upon impact is also important in the choice of scientific payloads that want to exploit the initial landing to study the asteroid surface mechanical properties (e.g., Murdoch et al., 2016). Using the ISAE-SUPAERO drop tower, we have performed a series of low-velocity collisions into granular material in low gravity. Reduced-gravity is simulated by releasing a free-falling projectile into a surface container with a downward acceleration less than that of Earth's gravity. The acceleration of the surface is controlled through the use an Atwood machine, or a system of pulleys and counterweights. In reducing the effective surface acceleration of the granular material, the confining pressure will be reduced, and the properties of the granular material will become more representative of those on an asteroid's surface. In addition, since both the surface and projectile are falling, the projectile requires a minimum amount of time to catch the surface before the collision begins. This extended free-fall increases the experiment duration, making it easier to use accelerometers and high-speed cameras for data collection. The experiment is built into an existing 5.5 m drop-tower frame and has required the custom design of all components, including the projectile, surface sample container, release mechanism and deceleration system (Sunday et al., 2016

  18. Experimental and Numerical Studies on the Formability of Materials in Hot Stamping and Cold Die Quenching Processes

    SciTech Connect

    Li, N.; Mohamed, M. S.; Cai, J.; Lin, J.; Balint, D.; Dean, T. A.

    2011-05-04

    Formability of steel and aluminium alloys in hot stamping and cold die quenching processes is studied in this research. Viscoplastic-damage constitutive equations are developed and determined from experimental data for the prediction of viscoplastic flow and ductility of the materials. The determined unified constitutive equations are then implemented into the commercial Finite Element code Abaqus/Explicit via a user defined subroutine, VUMAT. An FE process simulation model and numerical procedures are established for the modeling of hot stamping processes for a spherical part with a central hole. Different failure modes (failure takes place either near the central hole or in the mid span of the part) are obtained. To validate the simulation results, a test programme is developed, a test die set has been designed and manufactured, and tests have been carried out for the materials with different forming rates. It has been found that very close agreements between experimental and numerical process simulation results are obtained for the ranges of temperatures and forming rates carried out.

  19. Pilot Eye Scanning under Actual Single Pilot Instrument Flight

    NASA Astrophysics Data System (ADS)

    Rinoie, Kenichi; Sunada, Yasuto

    Operations under single pilot instrument flight rules for general aviation aircraft is known to be one of the most demanding pilot tasks. Scanning numerous instruments plays a key role for perception and decision-making during flight. Flight experiments have been done by a single engine light airplane to investigate the pilot eye scanning technique for IFR flights. Comparisons between the results by an actual flight and those by a PC-based flight simulator are made. The experimental difficulties of pilot eye scanning measurements during the actual IFR flight are discussed.

  20. Comparison of simulated and actual wind shear radar data products

    NASA Technical Reports Server (NTRS)

    Britt, Charles L.; Crittenden, Lucille H.

    1992-01-01

    Prior to the development of the NASA experimental wind shear radar system, extensive computer simulations were conducted to determine the performance of the radar in combined weather and ground clutter environments. The simulation of the radar used analytical microburst models to determine weather returns and synthetic aperture radar (SAR) maps to determine ground clutter returns. These simulations were used to guide the development of hazard detection algorithms and to predict their performance. The structure of the radar simulation is reviewed. Actual flight data results from the Orlando and Denver tests are compared with simulated results. Areas of agreement and disagreement of actual and simulated results are shown.

  1. Experimental Technique for Producing and Recording Precise Particle Impacts on Transparent Window Materials

    NASA Technical Reports Server (NTRS)

    Gray, Perry; Guven, Ibrahim

    2016-01-01

    A new facility for making small particle impacts is being developed at NASA. Current sand/particle impact facilities are an erosion test and do not precisely measure and document the size and velocity of each of the impacting particles. In addition, evidence of individual impacts is often obscured by subsequent impacts. This facility will allow the number, size, and velocity of each particle to be measured and adjusted. It will also be possible to determine which particle produced damage at a given location on the target. The particle size and velocity will be measured by high speed imaging techniques. Information as to the extent of damage and debris from impacts will also be recorded. It will be possible to track these secondary particles, measuring size and velocity. It is anticipated that this additional degree of detail will provide input for erosion models and also help determine the impact physics of the erosion process. Particle impacts will be recorded at 90 degrees to the particle flight path and also from the top looking through the target window material.

  2. Excess foundry sand characterization and experimental investigation in controlled low-strength material

    NASA Astrophysics Data System (ADS)

    Deng, An

    The objective of this dissertation is to provide support with technical data for the reuse of excess foundry sand. The dissertation addresses two topics: a statistical sound evaluation of the characterization of foundry waste streams, and a laboratory investigation to qualify excess foundry sand as a major component in controlled low-strength material (CLSM). The survival analysis statistical technique is developed for processing censored characterization data with significant confidence. Using this methodology, supported by abundant characterization datasets, foundry waste streams are characterized in full spectrum of general chemical parameters, metallic elements and organic compounds regarding bulk analysis and leachate characterization. Not limited to characterization and environmental impact, foundry waste streams are evaluated by factor analyses, which contributes to proper selection of factor and maximization of reuse marketplace of foundry waste streams. Excavatable CLSM and structural CLSM containing different types of excess foundry sands are investigated through laboratory experiments. Technical data regarding physical characteristics of excess foundry sands, design, behavior, performance and environmental impact of fresh and hardened CLSM are presented in details. Wide span of parameters are analyzed to evaluate the qualification of integrating excess foundry sands into CLSM.

  3. Experimental methods for the characterization of the frequency-dependent viscoelastic properties of soft materials

    PubMed Central

    Kazemirad, Siavash; K. Heris, Hossein; Mongeau, Luc

    2013-01-01

    A characterization method based on Rayleigh wave propagation was developed for the quantification of the frequency-dependent viscoelastic properties of soft materials at high frequencies; i.e., up to 4 kHz. Planar harmonic surface waves were produced on the surface of silicone rubber samples. The phase and amplitude of the propagating waves were measured at different locations along the propagation direction, which allowed the calculation of the complex Rayleigh wavenumbers at each excitation frequency using a transfer function method. An inverse wave propagation problem was then solved to obtain the complex shear/elastic moduli from the measured wavenumbers. In a separate, related investigation, dynamic indentation tests using atomic force microscopy (AFM) were performed at frequencies up to 300 Hz. No systematic verification study is available for the AFM-based method, which can be used when the dimensions of the test samples are too small for other existing testing methods. The results obtained from the Rayleigh wave propagation and AFM-based indentation methods were compared with those from a well-established method, which involves the generation of standing longitudinal compression waves in rod-shaped test specimens. The results were cross validated and qualitatively confirmed theoretical expectations presented in the literature for the frequency-dependence of polymers. PMID:23654420

  4. Experimental studies of lithium-based surface chemistry for fusion plasma-facing materials applications

    NASA Astrophysics Data System (ADS)

    Allain, J. P.; Rokusek, D. L.; Harilal, S. S.; Nieto-Perez, M.; Skinner, C. H.; Kugel, H. W.; Heim, B.; Kaita, R.; Majeski, R.

    2009-06-01

    Lithium has enhanced the operational performance of fusion devices such as: TFTR, CDX-U, FTU, T-11 M, and NSTX. Lithium in the solid and liquid state has been studied extensively in laboratory experiments including its erosion and hydrogen-retaining properties. Reductions in physical sputtering up to 40-60% have been measured for deuterated solid and liquid lithium surfaces. Computational modeling indicates that up to a 1:1 deuterium volumetric retention in lithium is possible. This paper presents the results of systematic in situ laboratory experimental studies on the surface chemistry evolution of ATJ graphite under lithium deposition. Results are compared to post-mortem analysis of similar lithium surface coatings on graphite exposed to deuterium discharge plasmas in NSTX. Lithium coatings on plasma-facing components in NSTX have shown substantial reduction of hydrogenic recycling. Questions remain on the role lithium surface chemistry on a graphite substrate has on particle sputtering (physical and chemical) as well as hydrogen isotope recycling. This is particularly due to the lack of in situ measurements of plasma-surface interactions in tokamaks such as NSTX. Results suggest that the lithium bonding state on ATJ graphite is lithium peroxide and with sufficient exposure to ambient air conditions, lithium carbonate is generated. Correlation between both results is used to assess the role of lithium chemistry on the state of lithium bonding and implications on hydrogen pumping and lithium sputtering. In addition, reduction of factors between 10 and 30 reduction in physical sputtering from lithiated graphite compared to pure lithium or carbon is also measured.

  5. An experimental investigation of the early dynamic impact behaviour of textile armour systems: Decoupling material from system response

    NASA Astrophysics Data System (ADS)

    Cepus, Elvis

    This work focuses on the early impact response of textile armour systems. A relatively new data acquisition system, the Enhanced Laser Velocity Sensor (ELVS), was refined and used to generate a large database of results for a 5.57 mm diameter, 3 gram, non-deforming projectile impacting single-ply configurations of Ballistic Nylon, two weaves of Kevlar 129, and Zylon (PBO) over a range of velocities from 61 m/s to 248 m/s. In addition, one Kevlar 129 material was tested in configurations of 2, 3, 4, 8 and 16 plies over a range of strike velocities from 90 m/s to 481 m/s. ELVS results consisted of high-resolution timehistories of displacement, velocity and energy for each system tested. The strain wave velocity and ballistic performance of each system was also determined. Results taken from during the impact event were analysed up to just prior to the strain-wave rebounding from the boundary and returning to the impact point---effectively removing boundary influences. Regardless of system type, a constant rate of energy absorption within the pre-rebound timeframe was found to exist, which scales with the strike velocity to approximately the 8/3-power. Well-established single fibre theory was modified and applied to woven materials. It was assumed that three primary energy absorption mechanisms exist; elastic strain, in-plane kinetic and out-of-plane kinetic. This simple model yields the experimentally observed 8/3 exponent and parametrically predicts the difference between the different single-ply material systems, but underpredicts the observed behaviour by a factor of 2 and cannot address the performance reduction with increasing ply count. This combined experimental and analytical work confirms the long-held assumption that single fibre wave physics is applicable to multi-ply woven systems. More significantly, for the first time, it decouples material response from overall system response and provides the experimental tools and methodology required to analyse

  6. Experimental investigations of material models for Ti-6A1-4V and 2024-T3

    SciTech Connect

    Leseur, D

    1999-05-03

    This report describes studies of the deformation and failure behavior of Ti-6Al-4V and 2024-T3 aluminum. Data was obtained at high strain rates and large strains using the split Hopkinson pressure bar technique. This information, plus additional data from the literature, was used to critically evaluate the ability of the Johnson Cook material model to represent the deformation and failure response of Ti-6AMV and 2024-T3 under conditions relevant to simulations of engine containment and the influence of uncontained engine debris on aircraft structures. This model is being used in the DYNA3D finite element code, which is being developed/validated for evaluating aircraft/engine designs relative to the federal airworthiness standards and for improving mitigation/containment technology. The results of the experimental work reported here were used to define a new set of material constants for the strength component of the Johnson Cook model for Ti-6Al-4V and 2024-T3. The capabilities and limitations of the model are reviewed. The model can accurately represent the stress-strain response of the materials. The major concern with the Johnson Cook material model is its ability to accurately represent the stress - strain rate response at strain rates greater than 10{sup 3}-10{sup 4} s{sup {minus}1}. Additional work is also needed to adequately account for failure via shear localization, which was the dominant failure mode at high strain rates in both materials. Failure modeling in both Ti-6Al-N and 2024-T3 will be considered further in future reports.

  7. Generating information-rich high-throughput experimental materials genomes using functional clustering via multitree genetic programming and information theory.

    PubMed

    Suram, Santosh K; Haber, Joel A; Jin, Jian; Gregoire, John M

    2015-04-13

    High-throughput experimental methodologies are capable of synthesizing, screening and characterizing vast arrays of combinatorial material libraries at a very rapid rate. These methodologies strategically employ tiered screening wherein the number of compositions screened decreases as the complexity, and very often the scientific information obtained from a screening experiment, increases. The algorithm used for down-selection of samples from higher throughput screening experiment to a lower throughput screening experiment is vital in achieving information-rich experimental materials genomes. The fundamental science of material discovery lies in the establishment of composition-structure-property relationships, motivating the development of advanced down-selection algorithms which consider the information value of the selected compositions, as opposed to simply selecting the best performing compositions from a high throughput experiment. Identification of property fields (composition regions with distinct composition-property relationships) in high throughput data enables down-selection algorithms to employ advanced selection strategies, such as the selection of representative compositions from each field or selection of compositions that span the composition space of the highest performing field. Such strategies would greatly enhance the generation of data-driven discoveries. We introduce an informatics-based clustering of composition-property functional relationships using a combination of information theory and multitree genetic programming concepts for identification of property fields in a composition library. We demonstrate our approach using a complex synthetic composition-property map for a 5 at. % step ternary library consisting of four distinct property fields and finally explore the application of this methodology for capturing relationships between composition and catalytic activity for the oxygen evolution reaction for 5429 catalyst compositions in a

  8. Experimental study and steady-state simulation of biogeochemical processes in laboratory columns with aquifer material

    NASA Astrophysics Data System (ADS)

    Amirbahman, Aria; Schönenberger, René; Furrer, Gerhard; Zobrist, Jürg

    2003-07-01

    Packed bed laboratory column experiments were performed to simulate the biogeochemical processes resulting from microbially catalyzed oxidation of organic matter. These included aerobic respiration, denitrification, and Mn(IV), Fe(III) and SO 4 reduction processes. The effects of these reactions on the aqueous- and solid-phase geochemistry of the aquifer material were closely examined. The data were used to model the development of alkalinity and pH along the column. To study the independent development of Fe(III)- and SO 4-reducing environments, two columns were used. One of the columns (column 1) contained small enough concentrations of SO 4 in the influent to render the reduction of this species unimportant to the geochemical processes in the column. The rate of microbially catalyzed reduction of Mn(IV) changed with time as evidenced by the variations in the initial rate of Mn(II) production at the head of the column. The concentration of Mn in both columns was controlled by the solubility of rhodochrosite (MnCO 3(S)). In the column where significant SO 4 reduction took place (column 2), the concentration of dissolved Fe(II) was controlled by the solubility of FeS. In column 1, where SO 4 reduction was not important, maximum dissolved Fe(II) concentrations were controlled by the solubility of siderite (FeCO 3(S)). Comparison of solid-phase and aqueous-phase data suggests that nearly 20% of the produced Fe(II) precipitates as siderite in column 1. The solid-phase analysis also indicates that during the course of experiment, approximately 20% of the total Fe(III) hydroxides and more than 70% of the amorphous Fe(III) hydroxides were reduced by dissimilatory iron reduction. The most important sink for dissolved S(-II) produced by the enzymatic reduction of SO 4 was its direct reaction with solid-phase Fe(III) hydroxides leading initially to the formation of FeS. Compared to this pathway, precipitation as FeS did not constitute an important sink for S(-II) in column

  9. RELAP5 Model of a Two-phase ThermoSyphon Experimental Facility for Fuels and Materials Irradiation

    SciTech Connect

    Carbajo, Juan J; McDuffee, Joel Lee

    2013-01-01

    The High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL) does not have a separate materials-irradiation flow loop and requires most materials and all fuel experiments to be placed inside a containment. This is necessary to ensure that internal contaminants such as fission products cannot be released into the primary coolant. As part of the safety basis justification, HFIR also requires that all experiments be able to withstand various accident conditions (e.g., loss of coolant) without generating vapor bubbles on the surface of the experiment in the primary coolant. As with any parallel flow system, HFIR is vulnerable to flow excursion events when vapor is generated in one of those flow paths. The effects of these requirements are to artificially increase experiment temperatures by introducing a barrier between the experimental materials and the HFIR coolant and to reduce experiment heat loads to ensure boiling doesn t occur. A new experimental facility for materials irradiation and testing in the HFIR is currently being developed to overcome these limitations. The new facility is unique in that it will have its own internal cooling flow totally independent of the reactor primary coolant and boiling is permitted. The reactor primary coolant will cool the outside of this facility without contacting the materials inside. The ThermoSyphon Test Loop (TSTL), a full scale prototype of the proposed irradiation facility to be tested outside the reactor, is being designed and fabricated (Ref. 1). The TSTL is a closed system working as a two-phase thermosyphon. A schematic is shown in Fig. 1. The bottom central part is the boiler/evaporator and contains three electric heaters. The vapor generated by the heaters will rise and be condensed in the upper condenser, the condensate will drain down the side walls and be circulated via a downcomer back into the bottom of the boiler. An external flow system provides coolant that simulates the HFIR primary coolant

  10. Experimental study on the fabrication of advanced materials for energy applications using high energy mechanical milling

    NASA Astrophysics Data System (ADS)

    Narayana Swamy, Ashvin Kumar

    The reaction of aluminum (Al) powder with water has the potential for on demand hydrogen generation. Conventional Al powders, however, react with water slowly due to a highly protective oxide layer on the particle surface. Current methods for Al activation involve harmful and expensive materials. The nano-scale Al powders also remain very expensive and have problems such as a large amount of oxide on the surface. The use of aluminum in an energy generation cycle is also hindered by the fact that, although Al is the most abundant metal in the Earth's crust, its recovery from ore consumes a lot of energy. Recycling aluminum hydroxide, formed as a result of Al reaction with water, would also require large amounts of energy. The energy consumption for production of Al powder and hence its cost could be significantly reduced by using recycled aluminum scrap and waste where aluminum is contained in metallic, non-oxidized form. The research work presented here investigates the preparation of an activated aluminum powder from aluminum foil that is widely available as scrap and waste. The obtained results demonstrate that a highly reactive, fine powder can be obtained from Al foil by high-energy ball milling with sodium chloride (NaCl). The obtained powder readily reacts with hot water, releasing hydrogen. Note that NaCl is an environment-friendly additive that can easily be removed after milling and recycled. After washing NaCl out, the powders retain a high reactivity with respect to hot water. As compared to previously studied activation of commercial Al powders, a major advantage of the investigated process is the feasibility of using secondary aluminum. Another area of research presented here is the synthesis of gallium oxide (Ga2O3) nanostructures for their use as high-temperature sensors. Quasi one-dimensional nanomaterials are of great interest due to increased focus on their importance in physics research and also their applications in the nanodevices industry

  11. Theoretical and Experimental Thermal Performance Analysis of Complex Thermal Storage Membrane Containing Bio-Based Phase Change Material (PCM)

    SciTech Connect

    Kosny, Jan; Stovall, Therese K; Shrestha, Som S; Yarbrough, David W

    2010-01-01

    Since 2000, an ORNL research team has been testing different configurations of PCM-enhanced building envelop components to be used in residential and commercial buildings. During 2009, a novel type of thermal storage membrane was evaluated for building envelope applications. Bio-based PCM was encapsulated between two layers of heavy-duty plastic film forming a complex array of small PCM cells. Today, a large group of PCM products are packaged in such complex PCM containers or foils containing arrays of PCM pouches of different shapes and sizes. The transient characteristics of PCM-enhanced building envelope materials depend on the quality and amount of PCM, which is very often difficult to estimate because of the complex geometry of many PCM heat sinks. The only widely used small-scale analysis method used to evaluate the dynamic characteristics of PCM-enhanced building products is the differential scanning calorimeter (DSC). Unfortunately, this method requires relatively uniform, and very small, specimens of the material. However, in numerous building thermal storage applications, PCM products are not uniformly distributed across the surface area, making the results of traditional DSC measurements unrealistic for these products. In addition, most of the PCM-enhanced building products contain blends of PCM with fire retardants and chemical stabilizers. This combination of non-uniform distribution and non-homogenous composition make it nearly impossible to select a representative small specimen suitable for DSC tests. Recognizing these DSC limitations, ORNL developed a new methodology for performing dynamic heat flow analysis of complex PCM-enhanced building materials. An experimental analytical protocol to analyze the dynamic characteristics of PCM thermal storage makes use of larger specimens in a conventional heat-flow meter apparatus, and combines these experimental measurements with three-dimensional (3-D) finite-difference modeling and whole building energy

  12. Theoretical and Experimental Thermal Performance Analysis of Complex Thermal Storage Membrane Containing Bio-Based Phase Change Material (PCM)

    SciTech Connect

    Kosny, Jan; Stovall, Therese K; Shrestha, Som S; Yarbrough, David W

    2010-12-01

    Since 2000, an ORNL research team has been testing different configurations of PCM-enhanced building envelop components to be used in residential and commercial buildings. During 2009, a novel type of thermal storage membrane was evaluated for building envelope applications. Bio-based PCM was encapsulated between two layers of heavy-duty plastic film forming a complex array of small PCM cells. Today, a large group of PCM products are packaged in such complex PCM containers or foils containing arrays of PCM pouches of different shapes and sizes. The transient characteristics of PCM-enhanced building envelope materials depend on the quality and amount of PCM, which is very often difficult to estimate because of the complex geometry of many PCM heat sinks. The only widely used small-scale analysis method used to evaluate the dynamic characteristics of PCM-enhanced building products is the differential scanning calorimeter (DSC). Unfortunately, this method requires relatively uniform, and very small, specimens of the material. However, in numerous building thermal storage applications, PCM products are not uniformly distributed across the surface area, making the results of traditional DSC measurements unrealistic for these products. In addition, most of the PCM-enhanced building products contain blends of PCM with fire retardants and chemical stabilizers. This combination of non-uniform distribution and non-homogenous composition make it nearly impossible to select a representative small specimen suitable for DSC tests. Recognizing these DSC limitations, ORNL developed a new methodology for performing dynamic heat flow analysis of complex PCM-enhanced building materials. An experimental analytical protocol to analyze the dynamic characteristics of PCM thermal storage makes use of larger specimens in a conventional heat-flow meter apparatus, and combines these experimental measurements with three-dimensional (3-D) finite-difference modeling and whole building energy

  13. Visible and near-infrared reflectance spectroscopy of planetary analog materials. Experimental facility at Laboratoire de Planetologie de Grenoble.

    NASA Astrophysics Data System (ADS)

    Pommerol, A.; Brissaud, O.; Schmitt, B.; Quirico, E.; Doute, S.

    2007-08-01

    We have developed an original experimental facility designed to measure the bidirectional reflectance spectra of planetary analog materials. These measurements are helpful to interpret the observations of the spectrometers on board space probes in orbit around various Solar System bodies. The central part of the facility is the LPG spectrogonio- radiometer (Brissaud et al., 2004). This instrument provides measurements of samples BRDF (Bidirectional Reflectance Distribution Function) with high photometric and spectrometric accuracy in the spectral range of visible and near-infrared (0.3 - 4.8 microns). Measurements can be made at any value of incidence and emergence angle up to 80°. Azimuth angle is allowed to vary between 0 and 180°. The instrument was recently installed in a cold room allowing ambient temperatures as low as -20°C. This makes possible the measurements on different kinds of water ice samples (slab ice, frost, snow...) and mixtures of minerals and water ice with unprecedented accuracy. We also have designed and built a simulation chamber to measure spectra of samples (water ice and/or minerals) under an atmosphere with perfectly controlled temperature, pressure and composition. The main objective of this last improvement is the study of water exchange between planetary regolith analogs and atmosphere (adsorption/ desorption, condensation/sublimation). Experimental results will mainly apply to Martian water cycle and hydrated mineralogy. This simulation chamber also provides an efficient way to obtain bidirectional reflectance spectra of dry materials (removal of adsorbed water) with implications for planetary bodies without atmospheric or surface water (Titan, asteroids...). The reflectance spectroscopy facility is part of a large panel of instruments and techniques available at Laboratoire de Planetologie de Grenoble that provide complementary measurements on the same samples: infrared transmission spectroscopy of thin ice films, thick liquid and

  14. An experimental study on fracture mechanical behavior of rock-like materials containing two unparallel fissures under uniaxial compression

    NASA Astrophysics Data System (ADS)

    Huang, Yan-Hua; Yang, Sheng-Qi; Tian, Wen-Ling; Zeng, Wei; Yu, Li-Yuan

    2016-06-01

    Strength and deformability characteristics of rock with pre-existing fissures are governed by cracking behavior. To further research the effects of pre-existing fissures on the mechanical properties and crack coalescence process, a series of uniaxial compression tests were carried out for rock-like material with two unparallel fissures. In the present study, cement, quartz sand, and water were used to fabricate a kind of brittle rock-like material cylindrical model specimen. The mechanical properties of rock-like material specimen used in this research were all in good agreement with the brittle rock materials. Two unparallel fissures (a horizontal fissure and an inclined fissure) were created by inserting steel during molding the model specimen. Then all the pre-fissured rock-like specimens were tested under uniaxial compression by a rock mechanics servo-controlled testing system. The peak strength and Young's modulus of pre-fissured specimen all first decreased and then increased when the fissure angle increased from 0° to 75°. In order to investigate the crack initiation, propagation and coalescence process, photographic monitoring was adopted to capture images during the entire deformation process. Moreover, acoustic emission (AE) monitoring technique was also used to obtain the AE evolution characteristic of pre-fissured specimen. The relationship between axial stress, AE events, and the crack coalescence process was set up: when a new crack was initiated or a crack coalescence occurred, the corresponding axial stress dropped in the axial stress-time curve and a big AE event could be observed simultaneously. Finally, the mechanism of crack propagation under microscopic observation was discussed. These experimental results are expected to increase the understanding of the strength failure behavior and the cracking mechanism of rock containing unparallel fissures.

  15. Effect of temperature gradient on simultaneously experimental determination of thermal expansion coefficients and elastic modulus of thin film materials

    NASA Astrophysics Data System (ADS)

    Chen, Tei-Chen; Lin, Wen-Jong; Chen, Dao-Long

    2004-10-01

    Some specific experimental methods to simultaneously determine the thermal expansion coefficients αF and biaxial elastic modulus EF/(1-νF) of thin film materials have been reported recently. In these methods, the deflections or the curvature change of the thin films, deposited on two different types of circular disks with known material properties, generally can be measured with a variety of optical techniques. The temperature-dependent deflection behaviors of thin films are then obtained by heating the samples in the range from room temperature to a slightly higher temperature level at which the physical properties and microstructures of thin film materials still remain unchanged. By using the relations between stress, deflection, and temperature, the physical properties of thin films can be finally calculated by using the slopes of two lines in the stress versus temperature plot. These relations, however, are formulated under the condition of uniform temperature rise. If the heating processes of samples are conducted in the condition that there exists a small steady-state temperature gradient along the thickness of samples due to the effect of natural heat convection on the upper surface of thin film, the formulation mentioned above shall be modified. It is found that the deflection of sample induced by the small temperature gradient along the thickness due to natural heat convection is very significant and comparable to that induced by uniform temperature rise. Consequently, if the effect of this temperature gradient is carelessly disregarded in physical modeling, a significantly different value of elastic modulus may be misleadingly obtained. Some cases are exemplified and illustrated to show the influence of temperature gradient on the evaluation of material properties.

  16. Ion exchange removal of strontium from simulated and actual N-Springs well water at the Hanford 100-N Area

    SciTech Connect

    Brown, G.N.; Carson, K.J.; DesChane, J.R.; Elovich, R.J.; Kafka, T.M.; White, L.R.

    1996-06-01

    Experimental ion exchange studies are being conducted by the Pacific Northwest national Laboratory (PNNL) under the Efficient Separations and Processing (ESP) Crosscutting Program to evaluate newly emerging materials and technologies for removing cesium, strontium, technetium, and transuranic elements from simulated and actual wastes at Hanford. Previous work focused on applications to treat high-level alkaline tank wastes, but many of the technologies can also be applied in process and ground-water remediation. Ultimately, each process must be evaluated in terms of life-cycle costs, removal efficiency, process chemical consumption and recycle, stability of materials exposed to chemicals and radiation, compatibility with other process streams, secondary waste generation, process and maintenance costs, and final material disposal. This report assesses the performance of the 3M-designed Process Absorber Development Unit (PADU) and the AlliedSignal-produced sodium nonatitanate (NaTi) material in trace quantities of strontium from simulated and actual Hanford N-Springs ground water. The experimental objective was to determine the strontium-loading breakthrough profile of a proprietary 3M-engineered material in either disk or cartridge forms.

  17. Molecular concept and experimental evidence of H2O, CH4 and CO2 adsorption on organic material

    NASA Astrophysics Data System (ADS)

    Gensterblum, Yves; Krooss, Bernhard; Busch, Andreas

    2014-05-01

    Unconventional gas, such as shale gas or coalbed methane offers an attractive low-carbon solution and furthermore provides possibilities for CO2-storage and coevally for enhanced gas recovery. In order to better understand gas and water interaction with organic matter (coal) of different maturity we developed a molecular concept with experimental and literature support for sorption of these fluids on organic material over the entire range of thermal maturity. With increasing burial depth and temperature CO2 and CH4 are the main volatiles released when organic material matures (cf. coalification). While most CO2 is generally dissolved in formation water and transported away from the coal, most CH4 (coalbed methane, CBM) remains adsorbed to the coal pore structure and is produced as unconventional gas. We present here the experimental basis and a conceptual model and to explain CO2 and CH4 sorption in the presence of water on coal with varying coal maturity (from lignite to anthracite). Adsorption experiments have been performed on different maturity coals at various temperatures, pressures up to 20 MPa and under dry and moist conditions. With increasing coal maturity we find for both gases a linear sorption capacity trend for moisture-equilibrated and a more parabolic trend for dry coal samples. When investigating the difference in CH4 and CO2 sorption capacity on coal of different maturity as a function of moisture content we infer that oxygen containing functional groups account for the selective sorption properties of gases and water to coals. Additionally restrictions in translational and vibrational movements of the sorbed gas molecules induced by adsorbed water molecules cause differences in the presence of water.

  18. 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

  19. 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

  20. 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

    2016-01-01

    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/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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

    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.

  2. Combined experimental and analytical study using cruciform specimen for testing advanced aeropropulsion materials under in-plane biaxial loading

    NASA Astrophysics Data System (ADS)

    Abdul-Aziz, Ali; Krause, David

    2006-03-01

    A new in-house test capability has been developed at the NASA Glenn Research Center to conduct highly critical tests in support of major and significant components of the Stirling Radioisotope Generator (SRG). It is to aid the development of analytical life prediction methodology and to experimentally assist in verifying the flight-design component's life. Components within the SRG such as the heater head pressure vessel endure a very high temperature environment for a long period of time. Such conditions impose life-limiting failure by means of material creep, a slow gradual increase in strain which leads to an eventual failure of the pressure vessel. To properly evaluate the performance and assist in the design of this component, testing under multiaxial loading setting is essential, since the heater head is subjected to a biaxial state of stress. Thus, the current work undertakes conducting analytical studies under equibiaxial and non-equi-biaxial loadings situations at various temperatures emulating creep environment. These analytical activities will utilize the finite element method to analyze cruciform type specimens both, under linear elastic and creep conditions. And further to calibrate the in-plane biaxial-test system. The specimen finite element model is generated with MSC/Patran [1] and analytical calculations are conducted with MARC and ANSYS finite element codes [2-3]. Complementing these calculations will undertake conducting experimental tests. However, only results pertaining to the analytical studies are reported and their impact on estimating the life of the component is evaluated.

  3. Experimental investigation of thermal characteristics of lithium ion battery using phase change materials combined with metallic foams and fins

    NASA Astrophysics Data System (ADS)

    Deng, Y. C.; Zhang, H. Y.; Xia, X.

    2016-08-01

    Phase change materials are of great interest in energy storage and energy management applications due to their high latent heat and excellent cycling stability. In this paper, the thermal characteristics of phase change materials (PCM) for thermal management of cylindrical 18650 lithium-ion battery (LIB) were experimentally investigated. A commercial paraffin wax with a melting temperaturerange between 47 - 53.8oC was used in this study. A metal cylinder with a heater was used to emulate the heat generation from a battery, which was surrounded with the paraffin PCM and containted in a metal housing. The experiment was conducted in an environmental test chamber with controlled ambient temperatures and power inputs. Both the battery temperature and the housing wall temperature were measured during steady-state heating and cyclic heating conditions. Since PCM has low thermal conductivity, thermal enhancement techniques were investigated by adding metal foams (MFs) or combining metallic foam and fins into the PCM to enhance the thermal conductivity. The battery temperatures were measured for all the cases and the results were analyzed and discussed.

  4. Simulation and Experimental Study on Effect of Phase Change Material Thickness to Reduce Temperature of Photovoltaic Panel

    NASA Astrophysics Data System (ADS)

    Indartono, Y. S.; Prakoso, S. D.; Suwono, A.; Zaini, I. N.; Fernaldi, B.

    2015-09-01

    Solar energy is promising renewable energy which can be applied in Indonesia. Average solar radiation in the country is 4.8 kWh/day/m2. Weakness of silicon-based photovoltaic (PV) is efficiency reduction caused by temperature increase. Many attempts have been done to reduce PV temperature. In previous study, palm oil, which is widely available in Indonesia, is suitable to be used as phase change material (PCM) to reduce PV temperature. In this study, thickness of aluminium rectangular-tube containing phase change material oil is varied. The tube is placed at back part of PV. Numerical and experimental study was done to evaluate the effect of tube thickness to the temperature reduction of the PV. Variation of tube thickness used in the experiment is 50.8mm, 76.2 mm, 101.6 mm. Both studies show that increase of PCM thickness reduces PV temperature. Higher PCM thickness cause large reduction on PV temperature. Simulation result shows there is an optimum thickness of the PCM which is applied to the PV.

  5. An experimental and analytical investigation into the effects of process vibrations on material removal rates during polishing

    NASA Astrophysics Data System (ADS)

    Mullany, B.; Mainuddin, M.; Williams, W.; Keanini, R.

    2013-06-01

    Experimental testing, using both commercially available polishing machines and a specially built test platform, demonstrates that material removal rates (MRRs) observed during polishing of fused silica are strongly affected by nanometer-scale vibration amplitudes. Specifically, a nanometer level increase in system vibrations can produce MRRs approximately 150% higher than on an inherently smoother running machine. Moreover the higher spatial frequency surface roughness values are little-effected by the spectral content of the polishing machine. Polishing under controlled conditions, using the test platform, shows that for vibration amplitudes, A ≲ 1.6 μm, and over a fairly wide range of vibration frequencies, MRR increases almost linearly with increasing input power. By contrast, for A ≳ 10 μm, MRR exhibits a rapid decay with increasing A. Order of magnitude analyses and physical arguments are presented in order to explain the qualitatively distinct MRR trends observed. In the small-amplitude limit, A ≲ 1.6 μm, two arguments are presented which suggest that the total observed removal rate, MRRtot, reflects the superposed action of chemical-mechanical removal, MRRcm, and vibration-driven, flow-induced removal, MRRflow, i.e., MRRtot=MRRcm+MRRflow. The analyses further indicate that MRRflow primarily reflects cyclic viscous shears and pressure gradients extant within the thin, non-Newtonian slurry film that exists between the polishing tool and workpiece. Shears and pressure gradients, and corresponding flow-induced MRRs, are, in turn, found to scale as √A /do ω, where A is the vibration amplitude, do is the characteristic gap thickness between the tool and workpiece, and ω is the vibration frequency. In the large-amplitude limit, A ≳ 5 μm, experimental measurements and a simple scaling argument show that the polishing slurry film becomes thick enough that the workpiece and polishing tool lose direct contact. In this limit, observed MRRs thus reflect

  6. Experimental and theoretical investigations of cadmium diffusion in vacancy-rich Cu(In, Ga)Se2 material

    NASA Astrophysics Data System (ADS)

    Biderman, Norbert J.

    Copper indium gallium selenide (Cu(In,Ga)Se2 or CIGS) has become a significant topic of research and development for photovoltaic application. CIGS photovoltaic devices have demonstrated record conversion efficiencies however are still below the maximum solar conversion efficiency. Losses in performance have been attributed structural defects including vacancies, doping, grain boundaries, and compositional non-uniformity that are poorly understood and controlled. The cadmium sulfide (CdS) buffer layer plays a critical role in high-performance CIGS photovoltaic devices, serving as the n-type component of the p-n junction formed with the p-type CIGS absorber layer. Cadmium diffusion into the CIGS surface during CdS deposition creates a buried p-n homojunction in addition to the CIGS/CdS p-n heterojunction. CdS is believed to assist in reducing carrier recombination at the CIGS/CdS interface, an important attribute of high-efficiency solar cells. In the present work, cadmium diffusion mechanisms in CIGS are experimentally investigated via secondary ion mass spectroscopy (SIMS) and Auger electron spectroscopy (AES). Two cadmium diffusion profiles with distinct Arrhenius diffusion kinetics within a single depth profile of the CIGS thin film are observed with SIMS and AES: an intense first-stage diffusion profile directly below the CIGS/CdS interface and a long-range, second-stage diffusion profile that extends deep into the thin film. Cadmium grain boundary diffusion is also detected in fine-grain CIGS samples. These multiple diffusion processes are quantified in the present work, and the two-stage cadmium diffusion profiles suggest distinctive lattice diffusion mechanisms. Calculations and modeling of general impurity diffusion via interstitial sites in CIGS are also conducted via numerical including cadmium, iron, and zinc. In the numerical simulations, the standard diffusion-reaction kinetics theory is extended to vacancy-rich materials like CIGS that contain 1 at

  7. Experimental constraints on the energy budget of dynamic gouge formation: effects of rock strength, material heterogeneity, and initial flaw characteristics

    NASA Astrophysics Data System (ADS)

    Griffith, Ashley; Barber, Troy; Borjas, Christopher; Ghaffari, Hamed

    2016-04-01

    Fault core materials are characterized by substantial grain size reduction relative to host and damage zone rocks. The properties of these materials control fault strength and frictional behavior, and they record valuable information about rupture and slip processes. At high strain rates and large stress amplitudes characteristic of earthquake rupture tips, rock failure passes through a fragmentation transition from discrete fracture to pulverization; therefore much of the observed grain size reduction at the leading edge of propagating earthquake ruptures. Past examinations of particle size distributions in gouge formed in the cores of natural faults have led to contrasting conclusions that during a single event, the energy associated with creation of new surface area during this grain size reduction can be as large as 50%, or as little as <1% of the earthquake energy budget; however these estimates are difficult to confirm due to (A) challenges associated with accurate particle size measurement and (B) uncertainty regarding the variety of (not-necessarily coseismic) physico-chemical processes that may contribute to the observed grain size reduction. Here we study the micromechanics and energy budget of dynamic rock fragmentation under impulsive compressive loads using a Split Hopkinson Pressure Bar. We present new experimental results on Arkansas Novaculite and Westerly Granite coupled with microstructural observations and BET surface area measurements of post-mortem specimens. We show that the energy partitioned into creation of new surface areas approaches a significant portion of the total dissipated energy during our experiments, but this partitioning can be buffered by the presence of flaws and/or significant material heterogeneity. The results of this work have important implications for lithologic controls on gouge formation and energy partitioning during earthquakes.

  8. Self-Actualization, Liberalism, and Humanistic Education.

    ERIC Educational Resources Information Center

    Porter, Charles Mack

    1979-01-01

    The relationship between personality factors and political orientation has long been of interest to psychologists. This study tests the hypothesis that there is no significant relationship between self-actualization and liberalism-conservatism. The hypothesis is supported. (Author)

  9. Experimental and numerical investigation on cladding of corrosion-erosion resistant materials by a high power direct diode laser

    NASA Astrophysics Data System (ADS)

    Farahmand, Parisa

    In oil and gas industry, soil particles, crude oil, natural gas, particle-laden liquids, and seawater can carry various highly aggressive elements, which accelerate the material degradation of component surfaces by combination of slurry erosion, corrosion, and wear mechanisms. This material degradation results into the loss of mechanical properties such as strength, ductility, and impact strength; leading to detachment, delamination, cracking, and ultimately premature failure of components. Since the failure of high valued equipment needs considerable cost and time to be repaired or replaced, minimizing the tribological failure of equipment under aggressive environment has been gaining increased interest. It is widely recognized that effective management of degradation mechanisms will contribute towards the optimization of maintenance, monitoring, and inspection costs. The hardfacing techniques have been widely used to enhance the resistance of surfaces against degradation mechanisms. Applying a surface coating improves wear and corrosion resistance and ensures reliability and long-term performance of coated parts. A protective layer or barrier on the components avoids the direct mechanical and chemical contacts of tool surfaces with process media and will reduce the material loss and ultimately its failure. Laser cladding as an advanced hardfacing technique has been widely used for industrial applications in order to develop a protective coating with desired material properties. During the laser cladding, coating material is fused into the base material by means of a laser beam in order to rebuild a damaged part's surface or to enhance its surface function. In the hardfacing techniques such as atmospheric plasma spraying (APS), high velocity oxygen-fuel (HVOF), and laser cladding, mixing of coating materials with underneath surface has to be minimized in order to utilize the properties of the coating material most effectively. In this regard, laser cladding offers

  10. Experimental high strain-rate deformation products of carbonate-silicate rocks: Comparison with terrestrial impact materials

    NASA Astrophysics Data System (ADS)

    van der Bogert, C. H.; Schultz, P. H.; Spray, J. G.

    2008-09-01

    as an individual mineral species, no pure lime was observed to be present. In the quartzite sample, CaO is present only as a component of the Ca- and Ca,Mg-silicates. In the fine-grained shear zone materials, however, elemental mapping and EMP analyses reveal an overall segregation of MgO and CaO [6], suggesting that CaO is mostly present in Casilicates and Ca,Mg-silicates with low MgO contents. Dolomitic marble sample. The dolomitic marble section exhibited thinner, shorter fractures than the quartzite sample. Mechanical twinning was induced by the deformation. The adhered friction products were very fine-grained material with larger, untwinned calcite (Fig. 2), and dendritic carbonates with a composition similar to huntite. Most of the secondary calcite had rounded margins, which suggested that they were molten during the experiment. The dendritic huntite-like carbonate, with a CO2 content higher than of these secondary carbonate grains (Fig. 3). However, calcite was the dominant secondary mineral. The finegrained portion of the shear zone material contained pervasive vesicles. The vesicles immediately adjacent to the secondary calcite grains were smaller than those adjacent to the dolomitic marble. This suggests that incorporation of CO2 near the calcite grains facilitated their growth. Discussion. The textures and compositions of the experimental products indicate that the dolomitic marble decarbonated in response to the high temperatures generated during experimental deformation. Simultaneously, the liberated CaO recombined with CO2 to form molten calcite in the shear zone. This effect, in part, is due to the lower decarbonation temperature for dolomite versus calcite [c.f., 7], which allows calcite to survive at higher temperatures than dolomite. In addition, the confining pressure during the experiment was high enough to allow calcite to be present as a liquid [c.f., 8]. Both the calcite and dendritic carbonate are likely products of back-reaction of CaO and

  11. Modeling disturbance-driven transport of unconsolidated materials using a rate process framework: Experimental investigation of granular creep

    NASA Astrophysics Data System (ADS)

    Roering, J. J.

    2002-12-01

    The movement of unconsolidated materials near the earth's surface is often driven by disturbances that occur at a range of spatial and temporal scales. The nature of these disturbances varies from highly stochastic, such as tree turnover (which is influenced by tree physiology, soil properties, storm frequency, and topography), to periodic and predictable, such as frost heave or creep (which is influenced by seasonal changes in temperature and moisture). To explore the effect of probabilistic disturbances on surface processes, we formulated a granular creep model analogous to rate process theory (RPT) used for chemical reactions (Eyring, 1936, J. Chem. Phys., v. 4, p. 283-291). According to the theory, individual particles must be energized to a height greater than adjacent particles in order for grain dilation and transport to occur. The height of neighboring particles (which is akin to activation energy in chemical reactions) varies with slope angle such that energy barriers get smaller in the downslope direction as slopes steepen. When slopes approach the friction-limited angle of repose, the height of energy barriers approaches zero and grains flow in the absence of disturbance. An exponential function is used to describe the probability distribution of particle excitation height although alternative distributions are possible. The exponent that describes the probability distribution increases with depth due to additional overburden. We tested model predictions of granular dynamics in an experimental sandpile. In the sandpile, acoustic energy serves as the disturbance agent such that grains dilate and flow in response. Particle velocities are controlled by the frequency of energy pulses that result in grain displacement. Using tracers to track particle trajectories, we observed a convex-up velocity profile near the surface of the sandpile, consistent with predictions of our RPT-based velocity model. In addition, we depth-integrated the velocity model to predict

  12. Correlation Between Material Properties of Ferroelectric Thin Films and Design Parameters for Microwave Device Applications: Modeling Examples and Experimental Verification

    NASA Technical Reports Server (NTRS)

    Miranda, Felix A.; VanKeuls, Fred W.; Subramanyam, Guru; Mueller, Carl H.; Romanofsky, Robert R.; Rosado, Gerardo

    2000-01-01

    The application of thin ferroelectric films for frequency and phase agile components is the topic of interest of many research groups worldwide. Consequently, proof-of-concepts (POC) of different tunable microwave components using either (HTS, metal)/ferroelectric thin film/dielectric heterostructures or (thick, thin) film "flip-chip" technology have been reported. Either as ferroelectric thin film characterization tools or from the point of view of circuit implementation approach, both configurations have their respective advantages and limitations. However, we believe that because of the progress made so far using the heterostructure (i.e., multilayer) approach, and due to its intrinsic features such as planar configuration and monolithic integration, a study on the correlation of circuit geometry aspects and ferroelectric material properties could accelerate the insertion of this technology into working systems. In this paper, we will discuss our study performed on circuits based on microstrip lines at frequencies above 10 GHz, where the multilayer configuration offers greater ease of insertion due to circuit's size reduction. Modeled results of relevant circuit parameters such as the characteristic impedance, effective dielectric constant, and attenuation as a function of ferroelectric film's dielectric constant, tans, and thickness, will be presented for SrTiO3 and Ba(x)Sr(1-x)TiO3 ferroelectric films. A comparison between the modeled and experimental data for some of these parameters will be presented.

  13. Experimental Investigation of Mechanical and Thermal properties of sisal fibre reinforced composite and effect of sic filler material

    NASA Astrophysics Data System (ADS)

    Surya Teja, Malla; Ramana, M. V.; Sriramulu, D.; Rao, C. J.

    2016-09-01

    With a view of exploring the potential use of natural recourses, we made an attempt to fabricate sisal fibre polymer composites by hand lay-up method. Natural fiber composites are renewable, cheap and biodegradable. Their easy availability, lower density, higher specific properties, lower cost, satisfactory mechanical and thermal properties, non-corrosive nature, makes them an attractive ecological alternative to glass, carbon or other man-made synthetic fibers. In this work, the effect of SiC on mechanical and thermal properties of natural sisal fiber composites are investigated. The composite has been made with and without SiC incorporating natural sisal fiber with polyester as bonding material. The experimental outcomes exhibited that the tensile strength of composite with 10%SiC 2.53 times greater than that of composite without SiC. The impact strength of composite with 10% SiC is 1.73 times greater than that of composite without SiC plain polyester. Thermal properties studied include thermal conductivity, specific heat capacity, thermal diffusivity, thermal degradation and stability. Three different samples with 0%, 5%, 10% SiC powder are considered. With the addition of SiC filler powder, thermal conductivity increases, specific heat capacity gradually increases then decreases, thermal diffusivity increases and thermal stability improves with Sic powder.

  14. Comparison of Model and Experimental Results for Material and Energy Flow in a Titanium Evaporation System with Deforming Interfaces

    SciTech Connect

    McClelland, M A; Westerberg, K W; Meier, T C; Braun, D G; Frischknecht, K D; Anklam, T M

    2003-05-12

    Finite element calculations and measurements are compared for material and energy flow in a system to evaporate pure titanium. A 40 kW electron beam is used to heat the end of a 7.62 cm diameter cylindrical rod which is fed vertically through a water-cooled crucible. Vapor emanates from a liquid pool in which flow is driven strongly by buoyancy and capillary forces. At high evaporation rates, the vapor exerts strong shear and normal forces on the liquid-vapor interface. The MELT finite element code is used to calculate steady-state, axisymmetric flow and temperature fields along with liquid-solid and liquid-vapor interface locations. The influence of the vapor on the liquid top surface is treated using boundary conditions with parameters derived from Monte Carlo simulations. The upper and lower interfaces of the liquid pool are tracked using a mesh structured with rotating spines. Experimental evaporation rates are obtained from measured feed rates, and heat flow rates are determined from measured temperature rises in the cooling water. The finite element model provides a good representation of the measured evaporation rates, heat flows, and lower pool boundary locations.

  15. Experimental Demonstration of the Molten Oxide Electrolysis Method for Oxygen and Iron Production from Simulated Lunar Materials

    NASA Technical Reports Server (NTRS)

    Curreri, P. A.; Ethridge, E.; Hudson, S.; Sen, S.

    2006-01-01

    This paper presents the results of a Marshall Space Flight Center funded effort to conduct an experimental demonstration of the processing of simulated lunar resources by the molten oxide electrolysis (MOE) process to produce oxygen and metal from lunar resources to support human exploration of space. Oxygen extracted from lunar materials can be used for life support and propellant, and silicon and metallic elements produced can be used for in situ fabrication of thin-film solar cells for power production. The Moon is rich in mineral resources, but it is almost devoid of chemical reducing agents, therefore, molten oxide electrolysis, MOE, is chosen for extraction, since the electron is the most practical reducing agent. MOE was also chosen for following reasons. First, electrolytic processing offers uncommon versatility in its insensitivity to feedstock composition. Secondly, oxide melts boast the twin key attributes of highest solubilizing capacity for regolith and lowest volatility of any candidate electrolytes. The former is critical in ensuring high productivity since cell current is limited by reactant solubility, while the latter simplifies cell design by obviating the need for a gas-tight reactor to contain evaporation losses as would be the case with a gas or liquid phase fluoride reagent operating at such high temperatures. In the experiments reported here, melts containing iron oxide were electrolyzed in a low temperature supporting oxide electrolyte (developed by D. Sadoway, MIT).

  16. Experimental and Theoretical Demonstration on the Transport Properties of Fused Ring Host Materials for Organic Light-Emitting Diodes

    NASA Astrophysics Data System (ADS)

    Tse, S. C.; So, S. K.; Yeung, M. Y.; Lo, C. F.; Wen, S. W.; Chen, C. H.

    2006-01-01

    The charge transport properties of three tertiary-butyl (t-Bu) substituted anthracene derivatives (ADN), critical blue host materials for organic light-emitting diodes (OLEDs), have been investigated experimentally and computationally. From time-of-flight (TOF) measurements, all ADN compounds exhibit ambipolar characters. The hole and electron mobilities are in the range (1--5)× 10-7 cm2 V-1 s-1 under an external applied field of about 1 MV cm-1. Un-substituted ADN has the highest carrier mobilities while heavily t-Bu substituted ADN has the least. The electron and hole conducting properties of are consistent with ab initio calculation, which indicates that the frontier orbitals are localized mainly on the anthracene moiety. t-Bu substitutions in ADN increase the hopping path lengths among the molecules and hence reduce the electron and hole mobilities. The results demonstrate that t-Bu substitution is an effective means of engineering the conductivity of organic charge transporter for OLED applications.

  17. Development and experimental validation of a calculation scheme for nuclear heating evaluation in the core of the OSIRIS material testing reactor

    SciTech Connect

    Malouch, F.

    2011-07-01

    The control of the temperature in material samples irradiated in a material testing reactor requires the knowledge of the nuclear heating caused by the energy deposition by neutrons and photons interacting in the irradiation device structures. Thus, a neutron-photonic three-dimensional calculation scheme has been developed to evaluate the nuclear heating in experimental devices irradiated in the core of the OSIRIS MTR reactor (CEA/Saclay Center). The aim is to obtain a predictive tool for the nuclear heating estimation in irradiation devices. This calculation scheme is mainly based on the TRIPOLI-4 three-dimensional continuous-energy Monte Carlo transport code, developed by CEA (Saclay Center). An experimental validation has been carried out on the basis of nuclear heating measurements performed in the OSIRIS core. After an overview of the experimental devices irradiated in the OSIRIS reactor, we present the calculation scheme and the first results of the experimental validation. (authors)

  18. Ion exchange removal of cesium from simulated and actual supernate from Hanford tanks 241-SY-101 and 241-SY-103

    SciTech Connect

    Brown, G.N.; Bontha, J.R.; Carlson, C.D.

    1995-09-01

    Pacific Northwest Laboratory (PNL), in conjunction with the Process Chemistry and Statistics Section of Westinghouse Hanford Company (WHC), conducted this study as part of the Supernatant Treatment Development Task for the Initial Pretreatment Module (IPM) Applied Engineering Project. The study assesses the performance of the CS-100 ion exchange material for removing cesium from simulated and actual alkaline supernate from Hanford tanks 241-SY-101 and 241-SY-103. The objective of these experiments is to compare the cesium ion exchange loading and elution profiles of actual and simulated wastes. Specific experimental objectives include (1) demonstration of decontamination factors (DF) for cesium removal, 92) verification of simulant performance, (3) investigation of waste/exchanger chemistry, and (4) determination of the radionuclide content of the regenerated CS-100 resin prior to disposal.

  19. Numerical Modeling and Experimental Validation by Calorimetric Detection of Energetic Materials Using Thermal Bimorph Microcantilever Array: A Case Study on Sensing Vapors of Volatile Organic Compounds (VOCs).

    PubMed

    Kang, Seok-Won; Fragala, Joe; Banerjee, Debjyoti

    2015-01-01

    Bi-layer (Au-Si₃N₄) microcantilevers fabricated in an array were used to detect vapors of energetic materials such as explosives under ambient conditions. The changes in the bending response of each thermal bimorph (i.e., microcantilever) with changes in actuation currents were experimentally monitored by measuring the angle of the reflected ray from a laser source used to illuminate the gold nanocoating on the surface of silicon nitride microcantilevers in the absence and presence of a designated combustible species. Experiments were performed to determine the signature response of this nano-calorimeter platform for each explosive material considered for this study. Numerical modeling was performed to predict the bending response of the microcantilevers for various explosive materials, species concentrations, and actuation currents. The experimental validation of the numerical predictions demonstrated that in the presence of different explosive or combustible materials, the microcantilevers exhibited unique trends in their bending responses with increasing values of the actuation current. PMID:26334276

  20. Realizing actual feedback control of complex network

    NASA Astrophysics Data System (ADS)

    Tu, Chengyi; Cheng, Yuhua

    2014-06-01

    In this paper, we present the concept of feedbackability and how to identify the Minimum Feedbackability Set of an arbitrary complex directed network. Furthermore, we design an estimator and a feedback controller accessing one MFS to realize actual feedback control, i.e. control the system to our desired state according to the estimated system internal state from the output of estimator. Last but not least, we perform numerical simulations of a small linear time-invariant dynamics network and a real simple food network to verify the theoretical results. The framework presented here could make an arbitrary complex directed network realize actual feedback control and deepen our understanding of complex systems.

  1. Is Physicality an Important Aspect of Learning through Science Experimentation among Kindergarten Students?

    ERIC Educational Resources Information Center

    Zacharia, Zacharias C.; Loizou, Eleni; Papaevripidou, Marios

    2012-01-01

    The purpose of this study was to investigate whether physicality (actual and active touch of concrete material), as such, is a necessity for science experimentation learning at the kindergarten level. We compared the effects of student experimentation with Physical Manipulatives (PM) and Virtual Manipulatives (VM) on kindergarten students'…

  2. Developing Human Resources through Actualizing Human Potential

    ERIC Educational Resources Information Center

    Clarken, Rodney H.

    2012-01-01

    The key to human resource development is in actualizing individual and collective thinking, feeling and choosing potentials related to our minds, hearts and wills respectively. These capacities and faculties must be balanced and regulated according to the standards of truth, love and justice for individual, community and institutional development,…

  3. [Actual diet of patients with gastrointestinal diseases].

    PubMed

    Loranskaia, T I; Shakhovskaia, A K; Pavliuchkova, M S

    2000-01-01

    The study of actual nutrition of patients with erosive-ulcerative lesions in the gastroduodenal zone and of patients with operated ulcer has revealed defects in intake of essential nutrients by these patients: overeating of animal fat and refined carbohydrates, deficiency of oil, vitamins A, B2, C, D and food fibers.

  4. Humanistic Education and Self-Actualization Theory.

    ERIC Educational Resources Information Center

    Farmer, Rod

    1984-01-01

    Stresses the need for theoretical justification for the development of humanistic education programs in today's schools. Explores Abraham Maslow's hierarchy of needs and theory of self-actualization. Argues that Maslow's theory may be the best available for educators concerned with educating the whole child. (JHZ)

  5. Group Counseling for Self-Actualization.

    ERIC Educational Resources Information Center

    Streich, William H.; Keeler, Douglas J.

    Self-concept, creativity, growth orientation, an integrated value system, and receptiveness to new experiences are considered to be crucial variables to the self-actualization process. A regular, year-long group counseling program was conducted with 85 randomly selected gifted secondary students in the Farmington, Connecticut Public Schools. A…

  6. Teenagers' Perceived and Actual Probabilities of Pregnancy.

    ERIC Educational Resources Information Center

    Namerow, Pearila Brickner; And Others

    1987-01-01

    Explored adolescent females' (N=425) actual and perceived probabilities of pregnancy. Subjects estimated their likelihood of becoming pregnant the last time they had intercourse, and indicated the dates of last intercourse and last menstrual period. Found that the distributions of perceived probability of pregnancy were nearly identical for both…

  7. Reproducing Actual Morphology of Planetary Lava Flows

    NASA Astrophysics Data System (ADS)

    Miyamoto, H.; Sasaki, S.

    1996-03-01

    Assuming that lava flows behave as non-isothermal laminar Bingham fluids, we developed a numerical code of lava flows. We take the self gravity effects and cooling mechanisms into account. The calculation method is a kind of cellular automata using a reduced random space method, which can eliminate the mesh shape dependence. We can calculate large scale lava flows precisely without numerical instability and reproduce morphology of actual lava flows.

  8. The Actual Apollo 13 Prime Crew

    NASA Technical Reports Server (NTRS)

    1970-01-01

    The actual Apollo 13 lunar landing mission prime crew from left to right are: Commander, James A. Lovell Jr., Command Module pilot, John L. Swigert Jr.and Lunar Module pilot, Fred W. Haise Jr. The original Command Module pilot for this mission was Thomas 'Ken' Mattingly Jr. but due to exposure to German measles he was replaced by his backup, Command Module pilot, John L. 'Jack' Swigert Jr.

  9. A self-instructional manual for installing low-cost/no-cost weatherization materials: Experimental validation with scouts.

    PubMed

    Pavlovich, M; Greene, B F

    1984-01-01

    In this study, we describe the development and evaluation of a self-instructional program for installing 10 low-cost/no-cost weatherization materials (e.g., weatherstripping, caulking). This program was a weatherization and retrofit manual (WARM) providing step-by-step instructions and illustrations. Boy and Girl Scouts participated and used either the WARM or existing product instructions (EPI) to apply the materials. Scouts installed the materials properly only when they used the WARM.

  10. A self-instructional manual for installing low-cost/no-cost weatherization materials: Experimental validation with scouts.

    PubMed

    Pavlovich, M; Greene, B F

    1984-01-01

    In this study, we describe the development and evaluation of a self-instructional program for installing 10 low-cost/no-cost weatherization materials (e.g., weatherstripping, caulking). This program was a weatherization and retrofit manual (WARM) providing step-by-step instructions and illustrations. Boy and Girl Scouts participated and used either the WARM or existing product instructions (EPI) to apply the materials. Scouts installed the materials properly only when they used the WARM. PMID:16795671

  11. Materials

    NASA Technical Reports Server (NTRS)

    Glaessgen, Edward H.; Schoeppner, Gregory A.

    2006-01-01

    NASA Langley Research Center has successfully developed an electron beam freeform fabrication (EBF3) process, a rapid metal deposition process that works efficiently with a variety of weldable alloys. The EBF3 process can be used to build a complex, unitized part in a layer-additive fashion, although the more immediate payoff is for use as a manufacturing process for adding details to components fabricated from simplified castings and forgings or plate products. The EBF3 process produces structural metallic parts with strengths comparable to that of wrought product forms and has been demonstrated on aluminum, titanium, and nickel-based alloys to date. The EBF3 process introduces metal wire feedstock into a molten pool that is created and sustained using a focused electron beam in a vacuum environment. Operation in a vacuum ensures a clean process environment and eliminates the need for a consumable shield gas. Advanced metal manufacturing methods such as EBF3 are being explored for fabrication and repair of aerospace structures, offering potential for improvements in cost, weight, and performance to enhance mission success for aircraft, launch vehicles, and spacecraft. Near-term applications of the EBF3 process are most likely to be implemented for cost reduction and lead time reduction through addition of details onto simplified preforms (casting or forging). This is particularly attractive for components with protruding details that would require a significantly large volume of material to be machined away from an oversized forging, offering significant reductions to the buy-to-fly ratio. Future far-term applications promise improved structural efficiency through reduced weight and improved performance by exploiting the layer-additive nature of the EBF3 process to fabricate tailored unitized structures with functionally graded microstructures and compositions.

  12. Determination of the Actual Contact Surface of a Brush Contact

    NASA Technical Reports Server (NTRS)

    Holm, Ragnar

    1944-01-01

    The number of partial contact surfaces of a brush-ring contact is measured by means of a statistical method. The particular brush is fitted with wicks - that is, insulated and cemented cylinders of brush material, terminating in the brush surface. The number of partial contact surfaces can be computed from the length of the rest periods in which such wicks remain without current. Resistance measurements enable the determination of the size of the contact surfaces. The pressure in the actual contact surface of a recently bedded brush is found to be not much lower than the Brinell hardness of the brush.

  13. Ultrasonic field profile evaluation in acoustically inhomogeneous anisotropic materials using 2D ray tracing model: Numerical and experimental comparison.

    PubMed

    Kolkoori, S R; Rahman, M-U; Chinta, P K; Ktreutzbruck, M; Rethmeier, M; Prager, J

    2013-02-01

    Ultrasound propagation in inhomogeneous anisotropic materials is difficult to examine because of the directional dependency of elastic properties. Simulation tools play an important role in developing advanced reliable ultrasonic non destructive testing techniques for the inspection of anisotropic materials particularly austenitic cladded materials, austenitic welds and dissimilar welds. In this contribution we present an adapted 2D ray tracing model for evaluating ultrasonic wave fields quantitatively in inhomogeneous anisotropic materials. Inhomogeneity in the anisotropic material is represented by discretizing into several homogeneous layers. According to ray tracing model, ultrasonic ray paths are traced during its energy propagation through various discretized layers of the material and at each interface the problem of reflection and transmission is solved. The presented algorithm evaluates the transducer excited ultrasonic fields accurately by taking into account the directivity of the transducer, divergence of the ray bundle, density of rays and phase relations as well as transmission coefficients. The ray tracing model is able to calculate the ultrasonic wave fields generated by a point source as well as a finite dimension transducer. The ray tracing model results are validated quantitatively with the results obtained from 2D Elastodynamic Finite Integration Technique (EFIT) on several configurations generally occurring in the ultrasonic non destructive testing of anisotropic materials. Finally, the quantitative comparison of ray tracing model results with experiments on 32mm thick austenitic weld material and 62mm thick austenitic cladded material is discussed.

  14. An experimental and theoretical investigation of the liquefaction dynamics of a phase change material in a normal gravity environment

    NASA Technical Reports Server (NTRS)

    Bain, R. L.; Stermole, F. J.; Golden, J. O.

    1972-01-01

    Experimental and theoretical investigations were undertaken to determine the role of gravity-induced free convection upon the liquefaction dynamics of a cylindrical paraffin slab under normal gravity conditions. The experimental equipment consisted of a test cell, a fluid-loop heating system, and a multipoint recorder. The test chamber was annular in shape with an effective radius of 1.585 cm and a length of 5.08 cm. The heating chamber was a 1.906 cm diameter tube going through the center of the test chamber, and connected to the fluid loop heating system. All experimental runs were made with the longitudinal axis of the test cell in the vertical direction to insure that convection was not a function of the angular axis of the cell. Ten melting runs were made at various hot wall temperatures. Also, two pure conduction solidification runs were made to determine an experimental latent heat of fusion.

  15. Experimental study of the effect of viscoelastic damping materials on noise and vibration reduction within railway vehicles

    NASA Astrophysics Data System (ADS)

    Fan, Rongping; Meng, Guang; Yang, Jun; He, Caichun

    2009-01-01

    Interior noise and vibration reduction has become one important concern of railway operating environments due to the influence of increased speeds and reduced vehicle weights for energy efficiency. Three types of viscoelastic damping materials, bitumen-based damping material, water-based damping coating and butyl rubber damping material, were developed to reduce the vibration and noise within railway vehicles. Two sleeper carriages were furnished with the new materials in different patterns of constrained-layer and free-layer damping treatment. The measurements of vibration and noise were carried out in three running carriages. It is found that the reduction effect of damping treatments depends on the running speed. The unweighted root-mean-square acceleration is reduced by 0.08-0.79 and 0.06-0.49 m/s 2 for the carriage treated by bitumen-based as well as water-based damping materials and water-based damping material, respectively. The first two materials reduce vibration in a wider frequency range of 63-1000 Hz than the last. It turns out that the damping treatments of the first two reduce the interior noise level by 5-8 dBA within the carriage, and the last damping material by 1-6 dBA. However, the specific loudness analysis of noises shows that the noise components between 125 and 250 Hz are dominant for the overall loudness, although the low-frequency noise is noticeably decreased by the damping materials. The measure of loudness is shown to be more accurate to assess reduction effect of the damping material on the acoustic comfort.

  16. Air resistance measurements on actual airplane parts

    NASA Technical Reports Server (NTRS)

    Weiselsberger, C

    1923-01-01

    For the calculation of the parasite resistance of an airplane, a knowledge of the resistance of the individual structural and accessory parts is necessary. The most reliable basis for this is given by tests with actual airplane parts at airspeeds which occur in practice. The data given here relate to the landing gear of a Siemanms-Schuckert DI airplane; the landing gear of a 'Luftfahrzeug-Gesellschaft' airplane (type Roland Dlla); landing gear of a 'Flugzeugbau Friedrichshafen' G airplane; a machine gun, and the exhaust manifold of a 269 HP engine.

  17. Explosive Percolation Transition is Actually Continuous

    NASA Astrophysics Data System (ADS)

    da Costa, R. A.; Dorogovtsev, S. N.; Goltsev, A. V.; Mendes, J. F. F.

    2010-12-01

    Recently a discontinuous percolation transition was reported in a new “explosive percolation” problem for irreversible systems [D. Achlioptas, R. M. D’Souza, and J. Spencer, Science 323, 1453 (2009)SCIEAS0036-807510.1126/science.1167782] in striking contrast to ordinary percolation. We consider a representative model which shows that the explosive percolation transition is actually a continuous, second order phase transition though with a uniquely small critical exponent of the percolation cluster size. We describe the unusual scaling properties of this transition and find its critical exponents and dimensions.

  18. Experimental investigation of the flow, oxidation, cooling, and thermal-fatigue characteristics of a laminated porous sheet material

    NASA Technical Reports Server (NTRS)

    Hickel, R. O.; Warren, E. L.; Kaufman, A.

    1972-01-01

    The basic flow and oxidation characteristics of a laminated porous material (Lamilloy) are presented. The oxidation characteristics of Lamilloy are compared to a wireform-type porous material for the case when both materials are made from Hastelloy-X alloy. The cooling performance of an air cooled vane made from Lamilloy, as determined from cascade tests made at gas temperatures ranging from 1388 to 1741 C (2350 to 3165 F) is also discussed, as well as of a cascade-type thermal fatigue test of the Lamilloy vane.

  19. Indicated and actual mass inventory measurements for an inverted U-tube steam generator

    SciTech Connect

    Loomis, G.G.; Plessinger, M.P.; Boucher, T.J.

    1986-01-01

    Results from an experimental investigation of actual versus indicated secondary liquid level in a steam generator at steaming conditions are presented. The experimental investigation was performed in two different small scale U-tube-in-shell steam generators at typical pressurized water reactor operating conditions (5-7 MPa; saturated) in the Semiscale facility. During steaming conditions, the indicated secondary liquid level was found to vary considerably from the actual ''bottled-up'' liquid level. These difference between indicated and actual liquid level are related to the frictional pressure drop associated with the two-phase steaming condition in the riser. Data from a series of bottle-up experiments (Simultaneously, the primary heat source and secondary feed and steam are terminated) are tabulated and the actual liquid level is correlated to the indicated liquid level.

  20. An integrated experimental and computational approach to material selection for sound proof thermally insulted enclosure of a power generation system

    NASA Astrophysics Data System (ADS)

    Waheed, R.; Tarar, W.; Saeed, H. A.

    2016-08-01

    Sound proof canopies for diesel power generators are fabricated with a layer of sound absorbing material applied to all the inner walls. The physical properties of the majority of commercially available sound proofing materials reveal that a material with high sound absorption coefficient has very low thermal conductivity. Consequently a good sound absorbing material is also a good heat insulator. In this research it has been found through various experiments that ordinary sound proofing materials tend to rise the inside temperature of sound proof enclosure in certain turbo engines by capturing the heat produced by engine and not allowing it to be transferred to atmosphere. The same phenomenon is studied by creating a finite element model of the sound proof enclosure and performing a steady state and transient thermal analysis. The prospects of using aluminium foam as sound proofing material has been studied and it is found that inside temperature of sound proof enclosure can be cut down to safe working temperature of power generator engine without compromise on sound proofing.

  1. Experimental Investigation of Three-Dimensional (3-D) Material Flow Pattern in Thick Dissimilar 2050 Friction-Stir Welds

    NASA Astrophysics Data System (ADS)

    Avettand-Fènoël, Marie-Noëlle; Taillard, Roland; Laye, Julien; Odièvre, Thierry

    2014-02-01

    The current microstructural investigation performed at various scales deals with the three-dimensional (3-D) material flow in thick dissimilar Airware™ 2050 friction-stir butt welds (Airware, Newport Beach, CA) because of the scarcity of the results obtained with thicker than 8 mm joints and the lack of detailed interpretation of features in the longitudinal direction. An additional originality consists in the study of material flow under the probe tip. In the current case of thick plates, the variation of local temperature along the weld depth is of key importance for the material flow. Indeed, it governs the slight difference of local mechanical behavior between both materials and therefore the shift of the interface, which was clearly put into evidence by means of a difference of Mn content as small as 0.3 pct between both alloys. This importance of temperature for the malleability also entails the pear shape of the nugget as well as a change of grains orientation along the depth in the thermomechanically affected zone. Due to the modification of tool-material adhesion with temperature, a new phenomenological model of material flow for thick friction-stir welds is proposed. In accordance with their difference of origin, the coexistence of onion rings and serrated interface is also highlighted.

  2. Me and My Environment, Unit IV: Transfer and Cycling of Materials in My Environment, Experimental Edition 1973-74.

    ERIC Educational Resources Information Center

    Biological Sciences Curriculum Study, Boulder, CO.

    The experimental 1973-74 edition of Unit IV consists of 28 life science curriculum activities for 13- to 16-year-old educable mentally handicapped children. The role of the teacher in continuing field trials is noted and environmental themes and elements, inquiry skills, problem solving skills, and applicational behaviors and attitudes are…

  3. Numerical Modeling and Experimental Validation by Calorimetric Detection of Energetic Materials Using Thermal Bimorph Microcantilever Array: A Case Study on Sensing Vapors of Volatile Organic Compounds (VOCs)

    PubMed Central

    Kang, Seok-Won; Fragala, Joe; Banerjee, Debjyoti

    2015-01-01

    Bi-layer (Au-Si3N4) microcantilevers fabricated in an array were used to detect vapors of energetic materials such as explosives under ambient conditions. The changes in the bending response of each thermal bimorph (i.e., microcantilever) with changes in actuation currents were experimentally monitored by measuring the angle of the reflected ray from a laser source used to illuminate the gold nanocoating on the surface of silicon nitride microcantilevers in the absence and presence of a designated combustible species. Experiments were performed to determine the signature response of this nano-calorimeter platform for each explosive material considered for this study. Numerical modeling was performed to predict the bending response of the microcantilevers for various explosive materials, species concentrations, and actuation currents. The experimental validation of the numerical predictions demonstrated that in the presence of different explosive or combustible materials, the microcantilevers exhibited unique trends in their bending responses with increasing values of the actuation current. PMID:26334276

  4. An experimental and numerical study on the effect of some properties of non-metallic materials on the ice adhesion level

    NASA Astrophysics Data System (ADS)

    Piles Moncholi, Eduardo

    The rise of environmentalism in every sector of industry has led aircraft and engine manufacturing companies to develop new generations of more environmentally friendly engines. Companies are in a constant search for new manufacturing and production techniques in order to improve their products, from the environmental point of view, by gaining efficiency in manufacturing techniques and reduce the fuel consumption and emissions in-flight. Having this scenario in mind, the sponsor of this project is interested in understanding how changing the blade materials, currently titanium alloys, for other lighter materials, such as composites, is going to have an effect on overall gas turbine efficiency. In this Project the influence of the stiffness and coating thickness of those non-metallic materials suitable to be employed as coatings on gas turbine fan blades, from the icing point of view, are studied. The methodology is based on a study of linear elastic fracture mechanics of bi-material junctions and will extrapolate the general problem to the ice-coatings case, by obtaining experimental data from tests carried out in an icing tunnel. It was observed that the coating stiffness has an influence on the adhesion level of ice to less stiff materials, if compared with the adhesion level of ice to metals. We also describe how a 0.5 millimetre thin polymeric coating placed over a metallic substrate is enough to reduce the adhesion level of ice, hiding any effect that the underneath materials might have on the adhesion level..

  5. The actual status of Astronomy in Moldova

    NASA Astrophysics Data System (ADS)

    Gaina, A.

    The astronomical research in the Republic of Moldova after Nicolae Donitch (Donici)(1874-1956(?)) were renewed in 1957, when a satellites observations station was open in Chisinau. Fotometric observations and rotations of first Soviet artificial satellites were investigated under a program SPIN put in action by the Academy of Sciences of former Socialist Countries. The works were conducted by Assoc. prof. Dr. V. Grigorevskij, which conducted also research in variable stars. Later, at the beginning of 60-th, an astronomical Observatory at the Chisinau State University named after Lenin (actually: the State University of Moldova), placed in Lozovo-Ciuciuleni villages was open, which were coordinated by Odessa State University (Prof. V.P. Tsesevich) and the Astrosovet of the USSR. Two main groups worked in this area: first conducted by V. Grigorevskij (till 1971) and second conducted by L.I. Shakun (till 1988), both graduated from Odessa State University. Besides this research areas another astronomical observations were made: Comets observations, astroclimate and atmospheric optics in collaboration with the Institute of the Atmospheric optics of the Siberian branch of the USSR (V. Chernobai, I. Nacu, C. Usov and A.F. Poiata). Comets observations were also made since 1988 by D. I. Gorodetskij which came to Chisinau from Alma-Ata and collaborated with Ukrainean astronomers conducted by K.I. Churyumov. Another part of space research was made at the State University of Tiraspol since the beggining of 70-th by a group of teaching staff of the Tiraspol State Pedagogical University: M.D. Polanuer, V.S. Sholokhov. No a collaboration between Moldovan astronomers and Transdniestrian ones actually exist due to War in Transdniestria in 1992. An important area of research concerned the Radiophysics of the Ionosphere, which was conducted in Beltsy at the Beltsy State Pedagogical Institute by a group of teaching staff of the University since the beginning of 70-th: N. D. Filip, E

  6. MODIS Solar Diffuser: Modelled and Actual Performance

    NASA Technical Reports Server (NTRS)

    Waluschka, Eugene; Xiong, Xiao-Xiong; Esposito, Joe; Wang, Xin-Dong; Krebs, Carolyn (Technical Monitor)

    2001-01-01

    The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument's solar diffuser is used in its radiometric calibration for the reflective solar bands (VIS, NTR, and SWIR) ranging from 0.41 to 2.1 micron. The sun illuminates the solar diffuser either directly or through a attenuation screen. The attenuation screen consists of a regular array of pin holes. The attenuated illumination pattern on the solar diffuser is not uniform, but consists of a multitude of pin-hole images of the sun. This non-uniform illumination produces small, but noticeable radiometric effects. A description of the computer model used to simulate the effects of the attenuation screen is given and the predictions of the model are compared with actual, on-orbit, calibration measurements.

  7. 7 CFR 1437.101 - Actual production history.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 10 2014-01-01 2014-01-01 false Actual production history. 1437.101 Section 1437.101... Determining Yield Coverage Using Actual Production History § 1437.101 Actual production history. Actual production history (APH) is the unit's record of crop yield by crop year for the APH base period. The...

  8. 7 CFR 1437.101 - Actual production history.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 10 2012-01-01 2012-01-01 false Actual production history. 1437.101 Section 1437.101... Determining Yield Coverage Using Actual Production History § 1437.101 Actual production history. Actual production history (APH) is the unit's record of crop yield by crop year for the APH base period. The...

  9. 7 CFR 1437.101 - Actual production history.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 10 2011-01-01 2011-01-01 false Actual production history. 1437.101 Section 1437.101... Determining Yield Coverage Using Actual Production History § 1437.101 Actual production history. Actual production history (APH) is the unit's record of crop yield by crop year for the APH base period. The...

  10. 7 CFR 1437.101 - Actual production history.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 10 2013-01-01 2013-01-01 false Actual production history. 1437.101 Section 1437.101... Determining Yield Coverage Using Actual Production History § 1437.101 Actual production history. Actual production history (APH) is the unit's record of crop yield by crop year for the APH base period. The...

  11. 7 CFR 1437.101 - Actual production history.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Actual production history. 1437.101 Section 1437.101... Determining Yield Coverage Using Actual Production History § 1437.101 Actual production history. Actual production history (APH) is the unit's record of crop yield by crop year for the APH base period. The...

  12. Al2O3/Al Cermets by Plasma Spraying: Optical Response of Experimental and Numerically Represented Materials

    NASA Astrophysics Data System (ADS)

    Toru, D.; Echegut, R.; Quet, A.; De Sousa Meneses, D.; del Campo, L.; Piombini, H.; Echegut, P.; Bianchi, L.

    2016-01-01

    Optical properties of plasma-sprayed coatings and numerically represented samples were studied at wavelengths ranging from visible to mid-infrared. The paper focuses on Al2O3 and Al2O3/Al cermet coatings with different metal concentrations. Microstructure and composition of the samples were characterized in order to explain their optical response that is highly dependent on volume and/or surface scattering as a function of the wavelength range. 2D scanning electron microscopy and 3D x-ray microtomography images were exploited to get statistical data in order to numerically represent simplified samples from the complex microstructure of plasma-sprayed coatings. A Monte Carlo ray-tracing model, based on geometrical optical laws, was then applied to reproduce experimental trends of the acquired optical spectra. Good agreement with the experimental data was obtained.

  13. Geochemical and magnetic characteristics of aeolian transported materials under different near-surface wind fields: An experimental study

    NASA Astrophysics Data System (ADS)

    Wang, Xunming; Lang, Lili; Hua, Ting; Zhang, Caixia; Xia, Dunsheng

    2015-06-01

    By combining field investigations, field sampling, wind-tunnel experiments, and laboratory measurements, the relationships between near-surface winds and the geochemical and magnetic characteristics of wind-transported materials were statistically analyzed. Our study was conducted using bulk surface samples from a major potential dust source area in Central Asia (the Ala Shan Plateau). Under near-surface wind velocities ranging from 8 to 22 m/s, the coefficients of variation ranged between 1.6% and 14.9% for χlf, 1.4% and 11.0% for χARM, and 0.7% and 12.3% for SIRM of the transported materials. For the 26 elements and oxides investigated, the coefficients of variation of Ti, Cr, As, Zr, Ce, Pb, and Cu in the samples were greater than 10%. No consistent patterns were found between magnetic characteristics and elemental and iron oxide concentrations as a function of variations in near-surface wind velocities. In potential dust source areas under near-surface wind velocities, there are variations in the relationships between magnetic and geochemical characteristics in the fine fractions of transported materials with different particle sizes. Given the wide variation in magnetic and geochemical characteristics of aeolian-transported materials under different near-surface winds, their use as proxies for past climate reconstruction must be carefully appraised.

  14. Prediction of heavy metal removal by different liner materials from landfill leachate: modeling of experimental results using artificial intelligence technique.

    PubMed

    Turan, Nurdan Gamze; Gümüşel, Emine Beril; Ozgonenel, Okan

    2013-01-01

    An intensive study has been made to see the performance of the different liner materials with bentonite on the removal efficiency of Cu(II) and Zn(II) from industrial leachate. An artificial neural network (ANN) was used to display the significant levels of the analyzed liner materials on the removal efficiency. The statistical analysis proves that the effect of natural zeolite was significant by a cubic spline model with a 99.93% removal efficiency. Optimization of liner materials was achieved by minimizing bentonite mixtures, which were costly, and maximizing Cu(II) and Zn(II) removal efficiency. The removal efficiencies were calculated as 45.07% and 48.19% for Cu(II) and Zn(II), respectively, when only bentonite was used as liner material. However, 60% of natural zeolite with 40% of bentonite combination was found to be the best for Cu(II) removal (95%), and 80% of vermiculite and pumice with 20% of bentonite combination was found to be the best for Zn(II) removal (61.24% and 65.09%). Similarly, 60% of natural zeolite with 40% of bentonite combination was found to be the best for Zn(II) removal (89.19%), and 80% of vermiculite and pumice with 20% of bentonite combination was found to be the best for Zn(II) removal (82.76% and 74.89%). PMID:23844384

  15. Prediction of Heavy Metal Removal by Different Liner Materials from Landfill Leachate: Modeling of Experimental Results Using Artificial Intelligence Technique

    PubMed Central

    Turan, Nurdan Gamze; Gümüşel, Emine Beril; Ozgonenel, Okan

    2013-01-01

    An intensive study has been made to see the performance of the different liner materials with bentonite on the removal efficiency of Cu(II) and Zn(II) from industrial leachate. An artificial neural network (ANN) was used to display the significant levels of the analyzed liner materials on the removal efficiency. The statistical analysis proves that the effect of natural zeolite was significant by a cubic spline model with a 99.93% removal efficiency. Optimization of liner materials was achieved by minimizing bentonite mixtures, which were costly, and maximizing Cu(II) and Zn(II) removal efficiency. The removal efficiencies were calculated as 45.07% and 48.19% for Cu(II) and Zn(II), respectively, when only bentonite was used as liner material. However, 60% of natural zeolite with 40% of bentonite combination was found to be the best for Cu(II) removal (95%), and 80% of vermiculite and pumice with 20% of bentonite combination was found to be the best for Zn(II) removal (61.24% and 65.09%). Similarly, 60% of natural zeolite with 40% of bentonite combination was found to be the best for Zn(II) removal (89.19%), and 80% of vermiculite and pumice with 20% of bentonite combination was found to be the best for Zn(II) removal (82.76% and 74.89%). PMID:23844384

  16. Apollo-Soyuz pamphlet no. 9: General science. [experimental design in Astronomy, Biology, Geophysics, Aeronomy and Materials science

    NASA Technical Reports Server (NTRS)

    Page, L. W.; From, T. P.

    1977-01-01

    The objectives and planning activities for the Apollo-Soyuz mission are summarized. Aspects of the space flight considered include the docking module and launch configurations, spacecraft orbits, and weightlessness. The 28 NASA experiments conducted onboard the spacecraft are summarized. The contributions of the mission to the fields of astronomy, geoscience, biology, and materials sciences resulting from the experiments are explored.

  17. Fabrication and Characterization of Samples for a Material Migration Experiment on the Experimental Advanced Superconducting Tokamak (EAST).

    SciTech Connect

    Wampler, William R.; Van Deusen, Stuart B.

    2015-12-01

    This report documents work done for the ITER International Fusion Energy Organization (Sponsor) under a Funds-In Agreement FI 011140916 with Sandia National Laboratories. The work consists of preparing and analyzing samples for an experiment to measure material erosion and deposition in the EAST Tokamak. Sample preparation consisted of depositing thin films of carbon and aluminum onto molybdenum tiles. Analysis consists of measuring the thickness of films before and after exposure to helium plasma in EAST. From these measurements the net erosion and deposition of material will be quantified. Film thickness measurements are made at the Sandia Ion Beam Laboratory using Rutherford backscattering spectrometry and nuclear reaction analysis, as described in this report. This report describes the film deposition and pre-exposure analysis. Results from analysis after plasma exposure will be given in a subsequent report.

  18. Experimental analysis of quasi-static and dynamic fracture initiation toughness of gy4 armor steel material

    NASA Astrophysics Data System (ADS)

    Ren, Peng; Guo, Zitao

    Quasi-static and dynamic fracture initiation toughness of gy4 armour steel material are investigated using three point bend specimen. The modified split Hopkinson pressure bar (SHPB) apparatus with digital image correlation (DIC) system is applied to dynamic loading experiments. Full-field deformation measurements are obtained by using DIC to elucidate on the strain fields associated with the mechanical response. A series of experiments are conducted at different strain rate ranging from 10-3 s-1 to 103 s-1, and the loading rate on the fracture initiation toughness is investigated. Specially, the scanning electron microscope imaging technique is used to investigate the fracture failure micromechanism of fracture surfaces. The gy4 armour steel material fracture toughness is found to be sensitive to strain rate and higher for dynamic loading as compared to quasi-static loading. This work is supported by National Nature Science Foundation under Grant 51509115.

  19. Nonlinear Hall effect for materials with weak thermoelectric power coefficients: preliminary comparisons between theoretical results of the thermodynamic field theory and experimental data.

    PubMed

    Sonnino, Giorgio; Peeters, Philippe

    2004-09-01

    This paper forms a part of a series of manuscripts which we intend to submit for publication in the near future, aiming to test the validity of the thermodynamic field theory (TFT), previously formulated, comparing the theoretical results with experimental data. In this particular case, we shall analyze the Hall effect. As known, when a magnetic field is applied at right angles to the direction of an electric current or a thermal gradient, galvano- and thermomagnetic effects appear in the material. In this paper, we shall show that if we study these effects in nonlinear regime, the TFT foresees an interesting effect: the nonlinear Hall effect. This prediction is herein submitted to experimental verifications. In this paper, we shall analyze this effect studying materials with weak thermoelectric power coefficients. We shall show the agreement between the theoretical predictions of the TFT and experiments. Experimental curves related to the nonlinear Hall effect allow us to determine the order of magnitude of the constant chi introduced in the TFT.

  20. Thermal Conductivity Measurements By Means of a New `Small Hot-Box' Apparatus: Manufacturing, Calibration and Preliminary Experimental Tests on Different Materials

    NASA Astrophysics Data System (ADS)

    Buratti, C.; Belloni, E.; Lunghi, L.; Barbanera, M.

    2016-05-01

    The evaluation of the thermal performance building components requires a high level of accuracy. Windows, doors and thermal bridges are not homogeneous, and their thermal transmittance can be evaluated by means of Hot-Box, used for full-scale elements. For homogeneous materials and one-dimensional heat flux, the thermal conductivity can be easily measured through other experimental apparatuses, such as the guarded hot plate and the heat flow meters. This study presents a new experimental apparatus named Small Hot-Box, built at the University of Perugia. No European standards are available for this innovative facility, but it takes into account some prescriptions of EN ISO 8990 and EN ISO 12567; it was built for the evaluation of the thermal properties of small specimens. The apparatus was designed, built, and calibrated by means of preliminary measurements. It is composed of a hot and a cold side, and the external walls are made of thick insulation. The thermal conductivity can be calculated by two different methodologies: the Hot-Box and the thermal flux meter method. Preliminary calibrations were carried out and different materials with known thermal transmittance were tested. The aim is the development of a new experimental apparatus; guidance documents could be defined for the measurements methodology requirements.

  1. Recycling of hazardous solid waste material using high-temperature solar process heat. 2. Reactor design and experimentation.

    PubMed

    Schaffner, Beatrice; Meier, Anton; Wuillemin, Daniel; Hoffelner, Wolfgang; Steinfeld, Aldo

    2003-01-01

    A novel high-temperature solar chemical reactor is proposed for the thermal recycling of hazardous solid waste material using concentrated solar power. It features two cavities in series, with the inner one functioning as the solar absorber and the outer one functioning as the reaction chamber. The solar reactor can handle thermochemical processes at temperatures above 1,300 K involving multiphases and controlled atmospheres. It further allows for batch or continuous mode of operation and for easy adjustment of the residence time of the reactants to match the kinetics of the reaction. A 10-kW solar reactor prototype was designed and tested for the carbothermic reduction of electric arc furnace dusts (EAFD). The reactor was subjected to mean solar flux intensities of 2,000 kW m(-2) and operated in both batch and continuous mode within the temperature range of 1,120-1,400 K. Extraction of over 90% of the toxic compounds originally contained in the EAFD was achieved while the condensable products of the off-gas contained mainly Zn, Pb, and Cl. The use of concentrated solar energy as the source of process heat offers the possibility of converting hazardous solid waste material into valuable commodities for processes in closed and sustainable material cycles.

  2. Characterisation of CIME, an experimental chamber for simulating interactions between materials of the cultural heritage and the environment.

    PubMed

    Chabas, A; Fouqueau, A; Attoui, M; Alfaro, S C; Petitmangin, A; Bouilloux, A; Saheb, M; Coman, A; Lombardo, T; Grand, N; Zapf, P; Berardo, R; Duranton, M; Durand-Jolibois, R; Jerome, M; Pangui, E; Correia, J J; Guillot, I; Nowak, S

    2015-12-01

    An approach consisting in combining in situ and laboratory experiments is often favoured for investigating the mechanisms involved in the weathering of the materials of the cultural heritage. However, the realistic simulation in the laboratory of the environmental conditions ruling the interactions of atmospheric compounds with materials is a very complex task. The aim of this work is to characterise CIME, a new chamber specially built to simulate the interactions between materials of the cultural heritage and the environment. The originality of this instrument is that beside the usual climatic parameters (temperature, relative humidity, solar radiation) and gaseous pollutants, it also allows the controlled injection of different types of particulate matter such as terrigenous, marine and anthropogenic. Therefore, varied realistic atmospheric environments (marine or urban) can be easily simulated within CIME. In addition to the technical description of CIME, this paper shows the first results obtained by the impact of gaseous pollutants on non-durable glass, bronze and limestone. The first experiments for the deposition of different particles (calcite, clays, soot and halite) are also presented. PMID:26250811

  3. Effects of Processing Residual Stresses on Fatigue Crack Growth Behavior of Structural Materials: Experimental Approaches and Microstructural Mechanisms

    NASA Astrophysics Data System (ADS)

    Lammi, Christopher J.; Lados, Diana A.

    2012-01-01

    Fatigue crack growth mechanisms of long cracks through fields with low and high residual stresses were investigated for a common structural aluminum alloy, 6061-T61. Bulk processing residual stresses were introduced in the material by quenching during heat treatment. Compact tension (CT) specimens were fatigue crack growth (FCG) tested at varying stress ratios to capture the closure and K max effects. The changes in fatigue crack growth mechanisms at the microstructural scale are correlated to closure, stress ratio, and plasticity, which are all dependent on residual stress. A dual-parameter Δ K- K max approach, which includes corrections for crack closure and residual stresses, is used uniquely to connect fatigue crack growth mechanisms at the microstructural scale with changes in crack growth rates at various stress ratios for low- and high-residual-stress conditions. The methods and tools proposed in this study can be used to optimize existing materials and processes as well as to develop new materials and processes for FCG limited structural applications.

  4. Experimental and theoretical investigation of a mesoporous K(x)WO3 material having superior mechanical strength.

    PubMed

    Dey, Sonal; Anderson, Sean T; Mayanovic, Robert A; Sakidja, Ridwan; Landskron, Kai; Kokoszka, Berenika; Mandal, Manik; Wang, Zhongwu

    2016-02-01

    Mesoporous materials with tailored properties hold great promise for energy harvesting and industrial applications. We have synthesized a novel tungsten bronze mesoporous material (K(x)WO3; x ∼ 0.07) having inverse FDU-12 type pore symmetry and a crystalline framework. In situ small angle X-ray scattering (SAXS) measurements of the mesoporous K(0.07)WO3 show persistence of a highly ordered meso-scale pore structure to high pressure conditions (∼18.5 GPa) and a material with remarkable mechanical strength despite having ∼35% porosity. Pressure dependent in situ SAXS measurements reveal a bulk modulus κ = 44 ± 4 GPa for the mesoporous K(x)WO3 which is comparable to the corresponding value for the bulk monoclinic WO3 (γ-WO3). Evidence from middle angle (MAXS) and wide angle X-ray scattering (WAXS), high-resolution transmission electron microscopy (HR-TEM) and Raman spectroscopy shows that the presence of potassium leads to the formation of a K-bearing orthorhombic tungsten bronze (OTB) phase within a monoclinic WO3 host structure. Our ab initio molecular dynamics calculations show that the formation of the OTB phase provides superior strength to the mesoporous K(0.07)WO3. PMID:26781181

  5. Characterisation of CIME, an experimental chamber for simulating interactions between materials of the cultural heritage and the environment.

    PubMed

    Chabas, A; Fouqueau, A; Attoui, M; Alfaro, S C; Petitmangin, A; Bouilloux, A; Saheb, M; Coman, A; Lombardo, T; Grand, N; Zapf, P; Berardo, R; Duranton, M; Durand-Jolibois, R; Jerome, M; Pangui, E; Correia, J J; Guillot, I; Nowak, S

    2015-12-01

    An approach consisting in combining in situ and laboratory experiments is often favoured for investigating the mechanisms involved in the weathering of the materials of the cultural heritage. However, the realistic simulation in the laboratory of the environmental conditions ruling the interactions of atmospheric compounds with materials is a very complex task. The aim of this work is to characterise CIME, a new chamber specially built to simulate the interactions between materials of the cultural heritage and the environment. The originality of this instrument is that beside the usual climatic parameters (temperature, relative humidity, solar radiation) and gaseous pollutants, it also allows the controlled injection of different types of particulate matter such as terrigenous, marine and anthropogenic. Therefore, varied realistic atmospheric environments (marine or urban) can be easily simulated within CIME. In addition to the technical description of CIME, this paper shows the first results obtained by the impact of gaseous pollutants on non-durable glass, bronze and limestone. The first experiments for the deposition of different particles (calcite, clays, soot and halite) are also presented.

  6. Caustic-Side Solvent Extraction: Prediction of Cesium Extraction for Actual Wastes and Actual Waste Simulants

    SciTech Connect

    Delmau, L.H.; Haverlock, T.J.; Sloop, F.V., Jr.; Moyer, B.A.

    2003-02-01

    This report presents the work that followed the CSSX model development completed in FY2002. The developed cesium and potassium extraction model was based on extraction data obtained from simple aqueous media. It was tested to ensure the validity of the prediction for the cesium extraction from actual waste. Compositions of the actual tank waste were obtained from the Savannah River Site personnel and were used to prepare defined simulants and to predict cesium distribution ratios using the model. It was therefore possible to compare the cesium distribution ratios obtained from the actual waste, the simulant, and the predicted values. It was determined that the predicted values agree with the measured values for the simulants. Predicted values also agreed, with three exceptions, with measured values for the tank wastes. Discrepancies were attributed in part to the uncertainty in the cation/anion balance in the actual waste composition, but likely more so to the uncertainty in the potassium concentration in the waste, given the demonstrated large competing effect of this metal on cesium extraction. It was demonstrated that the upper limit for the potassium concentration in the feed ought to not exceed 0.05 M in order to maintain suitable cesium distribution ratios.

  7. Theoretical and experimental investigations of the properties of Ge2Sb2Te5 and indium-doped Ge2Sb2Te5 phase change material

    NASA Astrophysics Data System (ADS)

    Singh, Gurinder; Kaura, Aman; Mukul, Monika; Singh, Janpreet; Tripathi, S. K.

    2014-06-01

    We have carried out comprehensive computational and experimental study on the face-centered cubic Ge2Sb2Te5 (GST) and indium (In)-doped GST phase change materials. Structural calculations, total density of states and crystal orbital Hamilton population have been calculated using first-principle calculation. 5 at.% doping of In weakens the Ge-Te, Sb-Te and Te-Te bond lengths. In element substitutes Sb to form In-Te-like structure in the GST system. In-Te has a weaker bond strength compared with the Sb-Te bond. However, both GST and doped alloy remain in rock salt structure. It is more favorable to replace Sb with In than with any other atomic position. X-ray diffraction (XRD) analysis has been carried out on thin film of In-doped GST phase change materials. XRD graph reveals that In-doped phase change materials have rock salt structure with the formation of In2Te3 crystallites in the material. Temperature dependence of impedance spectra has been calculated for thin films of GST and doped material. Thickness of the as-deposited films is calculated from Swanepoel method. Absorption coefficient (α) has been calculated for amorphous and crystalline thin films of the alloys. The optical gap (indirect band gap) energy of the amorphous and crystalline thin films has also been calculated by the equation α hν = β (hν - E_{{g }} )2 . Optical contrast (C) of pure and doped phase change materials have also been calculated. Sufficient optical contrast has been found for pure and doped phase change materials.

  8. Excess Foundry Sand Characterization and Experimental Investigation in Controlled Low-Strength Material and Hot-Mixing Asphalt

    SciTech Connect

    Pauul J. Tikalsky

    2004-10-31

    This report provides technical data regarding the reuse of excess foundry sand. The report addresses three topics: (1) a statistically sound evaluation of the characterization of foundry sand, (2) a laboratory investigation to qualify excess foundry sand as a major component in controlled low-strength material (CLSM), and (3) the identification of the best methods for using foundry sand as a replacement for natural aggregates for construction purposes, specifically in asphalt paving materials. The survival analysis statistical technique was used to characterize foundry sand over a full spectrum of general chemical parameters, metallic elements, and organic compounds regarding bulk analysis and leachate characterization. Not limited to characterization and environmental impact, foundry sand was evaluated by factor analyses, which contributes to proper selection of factor and maximization of the reuse marketplace for foundry sand. Regarding the integration of foundry sand into CLSM, excavatable CLSM and structural CLSM containing different types of excess foundry sands were investigated through laboratory experiments. Foundry sand was approved to constitute a major component in CLSM. Regarding the integration of foundry sand into asphalt paving materials, the optimum asphalt content was determined for each mixture, as well as the bulk density, maximum density, asphalt absorption, and air voids at N{sub ini}, N{sub des}, and N{sub max}. It was found that foundry sands can be used as an aggregate in hot-mix asphalt production, but each sand should be evaluated individually. Foundry sands tend to lower the strength of mixtures and also may make them more susceptible to moisture damage. Finally, traditional anti-stripping additives may decrease the moisture sensitivity of a mixture containing foundry sand, but not to the level allowed by most highway agencies.

  9. Excess Foundry Sand Characterization and Experimental Investigation in Controlled Low-Strength Material and Hot-Mixing Asphalt

    SciTech Connect

    Tikalsky, Paul J.; Bahia, Hussain U.; Deng, An; Snyder, Thomas

    2004-10-15

    This report provides technical data regarding the reuse of excess foundry sand. The report addresses three topics: a statistically sound evaluation of the characterization of foundry sand, a laboratory investigation to qualify excess foundry sand as a major component in controlled low-strength material (CLSM), and the identification of the best methods for using foundry sand as a replacement for natural aggregates for construction purposes, specifically in asphalt paving materials. The survival analysis statistical technique was used to characterize foundry sand over a full spectrum of general chemical parameters, metallic elements, and organic compounds regarding bulk analysis and leachate characterization. Not limited to characterization and environmental impact, foundry sand was evaluated by factor analyses, which contributes to proper selection of factor and maximization of the reuse marketplace for foundry sand. Regarding the integration of foundry sand into CLSM, excavatable CLSM and structural CLSM containing different types of excess foundry sands were investigated through laboratory experiments. Foundry sand was approved to constitute a major component in CLSM. Regarding the integration of foundry sand into asphalt paving materials, the optimum asphalt content was determined for each mixture, as well as the bulk density, maximum density, asphalt absorption, and air voids at Nini, Ndes, and Nmax. It was found that foundry sands can be used as an aggregate in hot-mix asphalt production, but each sand should be evaluated individually. Foundry sands tend to lower the strength of mixtures and also may make them more susceptible to moisture damage. Finally, traditional anti-stripping additives may decrease the moisture sensitivity of a mixture containing foundry sand, but not to the level allowed by most highway agencies.

  10. Assessment of Cable Aging Equipment, Status of Acquired Materials, and Experimental Matrix at the Pacific Northwest National Laboratory

    SciTech Connect

    Fifield, Leonard S.; Westman, Matthew P.; Zwoster, Andy; Schwenzer, Birgit

    2015-03-30

    The need for increased understanding of the aging and degradation behavior for polymer components of nuclear power plant electrical cables is described in this report. The highest priority materials for study and the resources available at PNNL for these studies are also described. The anticipated outcomes of the PNNL work described are : improved understanding of appropriate accelerated aging conditions, improved knowledge of correlation between observable aging indicators and cable condition in support of advanced non-destructive evaluation methods, and practical knowledge of condition-based cable lifetime prediction.

  11. Tracking Actual Usage: The Attention Metadata Approach

    ERIC Educational Resources Information Center

    Wolpers, Martin; Najjar, Jehad; Verbert, Katrien; Duval, Erik

    2007-01-01

    The information overload in learning and teaching scenarios is a main hindering factor for efficient and effective learning. New methods are needed to help teachers and students in dealing with the vast amount of available information and learning material. Our approach aims to utilize contextualized attention metadata to capture behavioural…

  12. What Writing Represents What Scientists Actually Do?

    ERIC Educational Resources Information Center

    Robertson, Bill

    2005-01-01

    Often the writing that students in elementary school do in connection with science is their final report of a science fair project. They diligently file a report in the form of the scientific method--introduction, hypothesis, materials, procedure, results, and conclusion. This form of science writing persists through college courses in science,…

  13. Thermal Protection System Cavity Heating for Simplified and Actual Geometries Using Computational Fluid Dynamics Simulations with Unstructured Grids

    NASA Technical Reports Server (NTRS)

    McCloud, Peter L.

    2010-01-01

    Thermal Protection System (TPS) Cavity Heating is predicted using Computational Fluid Dynamics (CFD) on unstructured grids for both simplified cavities and actual cavity geometries. Validation was performed using comparisons to wind tunnel experimental results and CFD predictions using structured grids. Full-scale predictions were made for simplified and actual geometry configurations on the Space Shuttle Orbiter in a mission support timeframe.

  14. An experimental and analytical investigation of the rail shear-test method as applied to composite materials

    NASA Technical Reports Server (NTRS)

    Garcia, R.; Mcwithey, R. R.; Weisshaar, T. A.

    1979-01-01

    This report presents the results from an experimental and analytical investigation of the stress distributions occurring in a rail shear test. The effects of non-uniform stresses induced by differential thermal expansion, rail flexibility and specimen aspect ratio on measured shear modulus and ultimate strength of composite laminates are shown. A two-dimensional linearly elastic finite element model was used to analytically determine how various geometric parameters influenced the magnitude and distribution of inplane normal and shear stresses in a tensile rail shear specimen. Rail shear tests were conducted at room temperature and 589 K (600 F) on selected graphite-polyimide composite laminates using two titanium rail configurations. The analysis and test methods are discussed, and the results of the effects of the various parameters on shear modulus and ultimate strength are presented.

  15. Influence of shockwave profile on ejection of micron-scale material from shocked Sn surfaces: an experimental study

    SciTech Connect

    Zellner, Michael B; Byers, Mark E; Hammerberg, James E; Germann, Tim C; Dimonte, Guy; Rigg, Paulo A; Buttler, William T

    2009-01-01

    This effort experimentally investigates the relationship between shock-breakout pressure and the amount of micron-scale fragments ejected (ejecta) upon shock release at the metal/vacuum interface of Sn targets shocked with a supported shockwave. The results are compared with an analogous set derived from HE shocked Sn targets, Taylor shockwave loading. The supported shock-pulse was created by impacting a Sn target with a Ti64 (Ti-6Al-4V) impactor that was accelerated using a powder gun. Ejecta production at the free-surface or back-side of the Sn targets were characterized through use of piezoelectric pins and Asay foils, and heterodyne velocimetry verified the time of shock release and the breakout pressure.

  16. Experimental Study on Enhancing the Productivity of Solar Still Using Locally Available Material as a Storage Medium

    NASA Astrophysics Data System (ADS)

    Arjunan, Thottipalayam Vellingri; Aybar, Hikmet Şelli; Nedunchezhian, Natarajan

    2016-06-01

    This experimental study focuses on the effect of pebbles as an energy storage medium on the performance of a solar distillation system. Two single basin solar stills are fabricated with an effective area of 0.5 m2, the glass cover was tilted at 10° with respect to the horizontal. The experiments on the still were carried out under the same climatic conditions for two different modes of operations, (1) conventional still and (2) modified still (pebbles as storage medium). From the study, it could be concluded that (1) the productivity of solar still is increases 9.5 % when pebbles are used as storage medium (2) the maximum amount of heat losses occurs in the solar still is the combined effect of radiation and convection heat transfer from glass to ambient (3) pebbles have the potentiality to store the heat during high solar intensity period and to release the stored energy to water when the solar intensity is low.

  17. Experimental and Theoretical Investigations of Hot Isostatically Pressed-Produced Stainless Steel/High Alloy Tool Steel Compound Materials

    NASA Astrophysics Data System (ADS)

    Lindwall, Greta; Flyg, Jesper; Frisk, Karin; Sandberg, Odd

    2011-05-01

    Consolidation of tool steel powders and simultaneous joining to a stainless 316L steel are performed by hot isostatic pressing (HIP). Two tool steel grades are considered: a high vanadium alloyed carbon tool steel, and a high vanadium and chromium alloyed nitrogen tool steel. The boundary layer arising during diffusion bonding is in focus and, in particular, the diffusion of carbon and nitrogen over the joint. Measurements of the elemental concentration profiles and corrosion tests by the double loop-electrochemical potentiokinetic reactivation (DL-EPR) method are performed. Comparative calculations with the DICTRA software are performed and are found to be in agreement with the experimental results. It is found that the carbon tool steel grade has a more critical influence on the corrosion resistance of the stainless 316L steel in comparison to the nitrogen tool steel grade.

  18. Hydroplus experimental study of dry, saturated, and frozen geological materials. Technical report, 15 July 1991-30 September 1992

    SciTech Connect

    Gaffney, E.S.; Smith, E.A.

    1994-04-01

    The dynamic shock responses of eight (8) types of rock and grouts were determined from one-dimensional plate impact experiments to support the Defense Nuclear Agency (DNA) HYDROPLUS program. Hugoniot data and loading and release paths were measured using in-situ stress gauges or VISAR interferometry. Two NTS tuffs from the DISTANT ZENITH and HUNTERS TROPHY test beds, a grout, MJ-2, which was designed to match the DISTANT ZENITH tuff and three carbonate rocks, Danby marble, Fort Knox carbonates and Salem limestone were characterized. All of these materials were tested in a water saturated condition at ambient and frozen conditions. Additionally, the Salem limestone was characterized dry. Hugoniot data for ice was also measured. Experiments that simulated jointed rock formation were conducted using Danby marble to evaluate the effects of water- or ice-filled joints on the amplitude of a stress wave propagating through the formation. Hugoniot data, release adiabats, and propagated waveshapes are presented for the rocks, grout, and ice. The effects of freezing, porosity, and dolomitization of the limestones on the Hugoniot and wave propagation characteristics of these materials are detailed. Propagated wave profiles and measured attenuation rates are given for the simulated jointed rock experiments. Hugoniot, DISTANT ZENITH Tuff, HUNTERS TROPHY Tuff, Release Adiabat, MJ-2 Grout, Danby Marble, Ice, Jointed Rocks, Fort Knox Carbonates.

  19. A New Porcine Sponge Material for Temporary Embolization: An Experimental Short-Term Pilot Study in Swine

    SciTech Connect

    Louail, B.; Sapoval, M. Bonneau, M.; Wasseff, M.; Senechal, Q.; Gaux, J-C.

    2006-10-15

    Purpose. To evaluate the safety and efficacy of a porcine-derived gelfoam, Curaspon, for the temporary occlusion of the visceral arteries. Methods. Curaspon was used for the selective embolization of segmentary hepatic, unilateral polar renal, and single lumbar arteries of 10 pigs under general anesthesia. Sequential angiographic checks were carried out and the pigs killed between 3 days and 2 weeks later. Macroscopic and microscopic studies using standard techniques were used to evaluate the immediate efficacy of embolization, duration of and completeness of recanalization on angiography, macroscopic appearance of target-organ ischemia, and microscopic analysis of inflammatory reaction. Results. Immediate arterial occlusion was obtained in all cases. Renal arteries showed a total recanalization in 63% of cases on day 7 and 100% on day 14. Total hepatic recanalization was obtained in 100% of animals on day 7. All lumbar arteries were recanalized on day 14. Microscopic analysis in the kidney revealed a mild inflammatory reaction and a progressive lysis of the Curaspon (87% of samples at day 3 showed a persistence of Curaspon and 5% at day 14). In some cases, localized and partial destruction of the arterial wall was visualized. In the liver the same patterns were observed but resolved more completely and more rapidly. Conclusions. Curaspon is an efficient material for the temporary occlusion of visceral and parietal arteries in pigs. However, arterial aneurysms were observed and a relationship of these with the material cannot be excluded.

  20. Design of the Experimental Exposure Conditions to Simulate Ionizing Radiation Effects on Candidate Replacement Materials for the Hubble Space Telescope

    NASA Technical Reports Server (NTRS)

    Smith, L. Montgomery

    1998-01-01

    In this effort, experimental exposure times for monoenergetic electrons and protons were determined to simulate the space radiation environment effects on Teflon components of the Hubble Space Telescope. Although the energy range of the available laboratory particle accelerators was limited, optimal exposure times for 50 keV, 220 keV, 350 keV, and 500 KeV electrons were calculated that produced a dose-versus-depth profile that approximated the full spectrum profile, and were realizable with existing equipment. For the case of proton exposure, the limited energy range of the laboratory accelerator restricted simulation of the dose to a depth of .5 mil. Also, while optimal exposure times were found for 200 keV, 500 keV and 700 keV protons that simulated the full spectrum dose-versus-depth profile to this depth, they were of such short duration that the existing laboratory could not be controlled to within the required accuracy. In addition to the obvious experimental issues, other areas exist in which the analytical work could be advanced. Improved computer codes for the dose prediction- along with improved methodology for data input and output- would accelerate and make more accurate the calculational aspects. This is particularly true in the case of proton fluxes where a paucity of available predictive software appears to exist. The dated nature of many of the existing Monte Carlo particle/radiation transport codes raises the issue as to whether existing codes are sufficient for this type of analysis. Other areas that would result in greater fidelity of laboratory exposure effects to the space environment is the use of a larger number of monoenergetic particle fluxes and improved optimization algorithms to determine the weighting values.

  1. Consequences of Predicted or Actual Asteroid Impacts

    NASA Astrophysics Data System (ADS)

    Chapman, C. R.

    2003-12-01

    Earth impact by an asteroid could have enormous physical and environmental consequences. Impactors larger than 2 km diameter could be so destructive as to threaten civilization. Since such events greatly exceed any other natural or man-made catastrophe, much extrapolation is necessary just to understand environmental implications (e.g. sudden global cooling, tsunami magnitude, toxic effects). Responses of vital elements of the ecosystem (e.g. agriculture) and of human society to such an impact are conjectural. For instance, response to the Blackout of 2003 was restrained, but response to 9/11 terrorism was arguably exaggerated and dysfunctional; would society be fragile or robust in the face of global catastrophe? Even small impacts, or predictions of impacts (accurate or faulty), could generate disproportionate responses, especially if news media reports are hyped or inaccurate or if responsible entities (e.g. military organizations in regions of conflict) are inadequately aware of the phenomenology of small impacts. Asteroid impact is the one geophysical hazard of high potential consequence with which we, fortunately, have essentially no historical experience. It is thus important that decision makers familiarize themselves with the hazard and that society (perhaps using a formal procedure, like a National Academy of Sciences study) evaluate the priority of addressing the hazard by (a) further telescopic searches for dangerous but still-undiscovered asteroids and (b) development of mitigation strategies (including deflection of an oncoming asteroid and on- Earth civil defense). I exemplify these issues by discussing several representative cases that span the range of parameters. Many of the specific physical consequences of impact involve effects like those of other geophysical disasters (flood, fire, earthquake, etc.), but the psychological and sociological aspects of predicted and actual impacts are distinctive. Standard economic cost/benefit analyses may not

  2. Experimental Determination of Heat Transfer Within the Metal/Mold Gap in a DC Casting Mold: Part II. Effect of Casting Metal, Mold Material, and Other Casting Parameters

    NASA Astrophysics Data System (ADS)

    Prasad, Arvind; Bainbridge, Ian F.

    2013-07-01

    Extensive experimental studies were conducted to quantify the effect of different parameters that can affect the heat transfer from the metal to the mold during the steady-state phase of DC casting. In the first part previously published, the experimental technique was established and results were reported for the effect of gas type (atmosphere within the mold) and the gap between the metal and the mold. The results showed the significant effect of gas thermal conductivity and the metal-mold gap on the mold wall heat transfer coefficient. In this second publication on heat transfer in the mold wall region of a DC casting mold, the results from the effect of casting temperature, gas flow rate, casting alloy, mold material, and the mold insert material on the mold wall heat transfer coefficient are described. The experiments reported in the current paper show that these additional factors tested do not affect the heat flux through the mold wall to the same extent as the gap size or the gas type. The heat transfer coefficient changes by less than 5 pct when casting temperature is changed by ±25 K, less than 15 pct when the gas flow rate within the metal-mold gap flows at up to 3 LPM, and approximately 30 pct when the mold material is changed from stainless steel to AA601 to copper. Similar results were obtained when different insert materials were used. These results are explained with the help of an electrical analogy of heat transfer and are consistent with the heat transfer theory.

  3. Analytical and experimental results of the coefficient of thermal expansion of high-modulus graphite-epoxy materials

    SciTech Connect

    Romeo, G.; Frulla, G.

    1995-09-01

    The coefficient of thermal expansion (CTE) as determined by the Classical Laminate Theory is very sensitive to some orthotropic elastic constants and to the laminate layup. In particular, the non-Hookean behavior of a unidirectional lamina in the fiber direction have to be taken into account to exactly predict the CTE. To verify the theoretical analysis, a new test facility has been designed to carefully measure the CTE in advanced composite materials having a quasi zero value of CTE. Measurement error in the CTE was minimized by a careful choice of displacement sensors and the high control of their thermal stability. The results show that a variation of +/- 1 deg in the lamina orientation can change the CTE of the quasi-isotropic laminate up to -/+ 50.5% of the theoretical value. A variation of +/- 5% in the physical and mechanical properties can change the CTE up to -/+ 48%. 14 refs.

  4. An experimental investigation of surface roughness in the drilling of MWCNT doped carbon/epoxy polymeric composite material

    NASA Astrophysics Data System (ADS)

    Kumar, D.; Singh, K. K.

    2016-09-01

    The objective of this research is to investigate the effect of multi-walled carbon nanotube (MWCNT) loading on the surface roughness of drilled hole, in the drilling of MWCNT doped carbon/epoxy polymeric composite material. Root mean square roughness (Rq) was used to assess the effect of MWCNT. Rq was measured at the both side i.e. entrance and exit of hole. Experiment was performed using Box- Behnken Design to develop an empirical model to predict the surface roughness value at the entrance and exit. The developed model was accurate within the level of confidence. Due to loading of MWCNT in polymer matrix, surface roughness of hole at entrance and exit are improved.

  5. Theoretical and experimental study of organic nano-material for acetate anion based on 1, 10-phenanthroline.

    PubMed

    Shang, Xuefang; Zhao, Yuan; Wei, Xiaofang; Feng, Yaqian; Li, Xin; Gao, Shuyan; Xu, Xiufang

    2015-01-01

    New phenanthroline derivatives (1, 2, 3, 4) containing phenol groups have been synthesized and optimized. The nano-material of compound 2 was also developed. Their binding properties were evaluated for various biological anions (F(-), Cl(-), Br(-), I(-), AcO(-) and H(2)PO(4)(-)) by theoretical investigation, UV-vis, fluorescence, (1)HNMR titration experiments and these compounds all showed strong binding ability for AcO(-) without the interference of other anions tested. The anion binding ability could be regularized by electron push-pull properties of the ortho- or para- substituent on benzene. Theoretical investigation analysis revealed the effect of intramolecular hydrogen bond existed between -OH and other atoms in the structure of these compounds.

  6. Experimental tests of irradiation-anneal-reirradiation effects on mechanical properties of RPV plate and weld materials

    SciTech Connect

    Hawthorne, J.R.

    1996-01-01

    The Charpy-V (C{sub V}) notch ductility and tension test properties of three reactor pressure vessel (RPV) steel materials were determined for the 288{degree}C (550{degree}F) irradiated (I), 288{degree}C (550{degree}F) irradiated + 454{degree}C (850{degree}F)-168 h postirradiation annealed (IA), and 288{degree}C (550{degree}F) reirradiated (IAR) conditions. Total fluences of the I condition and the IAR condition were, respectively, 3.33 {times} 10{sup 19} n/cm{sup 2} and 4.18 {times} 10{sup 19} n/cm{sup 2}, E > 1 MeV. The irradiation portion of the IAR condition represents an incremental fluence increase of 1. 05 {times} 10{sup 19} n/cm{sup 2}, E > 1 MeV, over the I-condition fluence. The materials (specimens) were supplied by the Yankee Atomic Electric Company and represented high and low nickel content plates and a high nickel, high copper content weld deposit prototypical of the Yankee-Rowe reactor vessel. The promise of the IAR method for extending the fluence tolerance of radiation-sensitive steels and welds is clearly shown by the results. The annealing treatment produced full C{sub V} upper shelf recovery and full or nearly full recovery in the C{sub V} 41 J (30 ft-lb) transition temperature. The C{sub V} transition temperature increases produced by the reirradiation exposure were 22% to 43% of the increase produced by the first cycle irradiation exposure. A somewhat greater radiation embrittlement sensitivity and a somewhat greater reirradiation embrittlement sensitivity was exhibited by the low nickel content plate than the high nickel content plate. Its high phosphorus content is believed to be responsible. The IAR-condition properties of the surface vs. interior regions of the low nickel content plate are also compared.

  7. Analytical and experimental investigation of the feasibility of accelerated lifetime testing of materials exposed to an atomic oxygen beam

    NASA Technical Reports Server (NTRS)

    Albridge, Royal; Barnes, Alan; Tolk, Norman

    1993-01-01

    The interaction of atomic particles with surfaces is of both scientific and technological interest. Past work emphasizes the measurement of high-energy sputtering yields. Very little work utilized low-energy beams for which chemical and electronic effects can be important. Even less work has been carried out using well-defined low-energy projectiles. The use of low-energy, reactive projectiles permits one to investigate surface processes that have not been well characterized. As the energy of the projectile decreases, the collisional cascades and spikes, that are common for high-energy projectiles, become less important, and chemical and electronic effects can play a significant role. Aspects of particle-surface interactions are of concern in several areas of technology. For example, the erosion, desorption, and glow of surfaces of spacecraft in orbit are important in the arena of space technology. The materials studied under this contract are of possible use on the exterior portions of the power generation system of Space Station Freedom. Under the original designs, Space Station Freedom's power generation system would generate potential differences on the surface as high as 200 volts. Ions in the plasma that often surround orbiting vehicles would be accelerated by these potentials leading to bombardment and erosion of the exposed surfaces. The major constituent of the atmosphere, approximately 90 percent, in the low earth orbit region is atomic oxygen. Since atomic oxygen is extremely reactive with most materials, chemical effects can arise in addition to the physical sputtering caused by the acceleration of the oxygen ions. Furthermore, the incident oxygen ions can remain embedded in the exposed surfaces, altering the chemical composition of the surfaces. Since the effective binding energy of a chemically altered surface can be quite different from that of the pure substrate, the sputtering yield of a chemically altered surface is usually different also. The low

  8. Micro-X-Ray computed tomography of natural and experimental melt segregations and other geological materials with small absorption contrasts

    NASA Astrophysics Data System (ADS)

    Baumgartner, L.; Wohlers, A.; Müller, T.

    2003-04-01

    Micro X-ray tomography is rapidly advancing to an important tool for non-destructive 3-D imaging of geological and engineering materials. We have been using a Skyscan 1072 system (Skyscan, Belgium) to successfully image as diverse geological materials as sandstones, foraminifers, run products of hydrothermal partial melting experiments, and metamorphic rocks. The system has a conical x-ray source with a spot size of about 5µm. The X-ray source is powered by a 10W, 20--100kV, tunable supply. Images are acquired with a scintillator coupled by glass fiber optics to a 1024×1024 pixel, 12-bit CCD. The sample is rotated for 180^o (or 360^o) in steps as small as 0.24^o. Transmission image are back projected, using a Feldkamp algorithm, into a stack of up to 1000 1K×1K images, each of which represents a horizontal cross section of the sample. We have succeeded to image very low contrast systems (feldspar/quartz and olivine/calcite/dolomite), by using extended acquisition times (up to 24 hours), and low excitation voltages (30--40kV) in combination with aluminum filters to reduce beam hardening. Some quartzites collected in the Little Cottonwood contact aureole have been infiltrated by a pegmatitic liquid. These liquids are the products of partial melting in intercalated meta-pelites. 2-D images (thin sections) clearly show, that poly-crystalline interstitial feldspar and mica represent precipitates from the infiltrated pegmatitic liquid (acute quartz-feldspar junctions similar to melting experiments). The micro-CT images reveal a thin mica-feldspar network. It forms highly anastomosing, multiply interconnected networks surrounding quartz grains. They connect larger, up to 1mm sized ponds, located in triple junctions. These results have important consequences for porous melt transport in shallow crustal rocks. Micro-CT images of spinifex textured olivine in marbles from the Ubehebe Peak contact aureole (Death Valley, California) reveal two preferential growth

  9. Experimental results on the irradiation of nuclear fusion relevant materials at the dense plasma focus ‘Bora’ device

    NASA Astrophysics Data System (ADS)

    Cicuttin, A.; Crespo, M. L.; Gribkov, V. A.; Niemela, J.; Tuniz, C.; Zanolli, C.; Chernyshova, M.; Demina, E. V.; Latyshev, S. V.; Pimenov, V. N.; Talab, A. A.

    2015-06-01

    Samples of materials counted as perspective ones for use in the first-wall and construction elements in nuclear fusion reactors (FRs) with magnetic and inertial plasma confinement (W, Ti, Al, low-activated ferritic steel ‘Eurofer’ and some alloys) were irradiated in the dense plasma focus (DPF) device ‘Bora’ having a bank energy of ⩽5 kJ. The device generates hot dense (T ˜ 1 keV, n ˜ 1019 cm-3) deuterium plasma, powerful plasma streams (v ˜ 3 × 107 cm s-1) and fast (E ˜ 0.1 … 1.0 MeV) deuterons of power flux densities q up to 1010 and 1012 W cm-2 correspondingly. ‘Damage factor’ F = q × τ0.5 ensures an opportunity to simulate radiation loads (predictable for both reactors types) by the plasma/ion streams, which have the same nature and namely those parameters as expected in the FR modules. Before and after irradiation we provided investigations of our samples by means of a number of analytical techniques. Among them we used optical and scanning electron microscopy to understand character and parameters of damageability of the surface layers of the samples. Atomic force microscopy was applied to measure roughness of the surface after irradiation. These characteristics are quite important for understanding mechanisms and values of dust production in FR that may relate to tritium retention and emergency situations in FR facilities. We also applied two new techniques. For the surface we elaborated the portable x-ray diffractometer that combines x-ray single photon detection with high spectroscopic and angular resolutions. For bulk damageability investigations we applied an x-ray microCT system where x-rays were produced by a Hamamatsu microfocus source (150 kV, 500 µA, 5 µm minimum focal spot size). The detector was a Hamamatsu CMOS flat panel coupled to a fibre optic plate under the GOS scintillator. The reconstruction of three-dimensional data was run with Cobra 7.4 and DIGIX CT software while VG Studio Max 2.1, and Amira 5.3 were used for

  10. Experimental use of a cellulosic biopolymer as a new material for suburethral sling in the treatment of stress urinary incontinence

    PubMed Central

    Lucena, Roberto G.; Lima, Salvador V. C.; Aguiar, José L. de A.; Andrade, Rogerson T.; Pinto, Flávia C. M.; Vilar, Fabio O.

    2015-01-01

    ABSTRACT Purpose: To analyze the interaction between the cellulose exopolysaccharide (CEC) and urethral tissue when used as a pubovaginal sling. Materials and Methods: Forty Wistar rats were divided into four groups. In groups A and B the cellulose exopolysaccharide (CEC) was implanted around the urethral tissue (bladder neck below the upper margin) and the rats were sacrificed at 30 and 90 days. Similar procedure was used in groups C and D using a polypropylene mesh. After sacrifice bladder and urethra were sent for histological analysis. The histological parameters (inflammatory reaction) by evaluated by quantitative analysis. For collagen deposition analysis it was used stereological method. Results: The cellulose exopolysaccharide (CEC) was inert and well preserved at the implanted region at the time of examination. Morphologic alterations were not found at the CEC implant but some reactions of foreign body type were observed at the adjacent structures. In some areas a process of neovascular formation was observed. Stereological analysis at the suburethral area showed a significant difference in collagen presence in favor of CEC. Conclusions: The CEC implant showed adequate results when used as a suburethral sling with good integration to the host tissue, preserving its architecture. PMID:26742973

  11. Rashba semiconductor as spin Hall material: Experimental demonstration of spin pumping in wurtzite n -GaN:Si

    NASA Astrophysics Data System (ADS)

    Adhikari, R.; Matzer, M.; Martín-Luengo, A. Tarazaga; Scharber, M. C.; Bonanni, A.

    2016-08-01

    Pure spin currents in semiconductors are essential for implementation in the next generation of spintronic elements. Heterostructures of III-nitride semiconductors are currently employed as central building blocks for lighting and high-power devices. Moreover, the long relaxation times and the spin-orbit coupling (SOC) in these materials indicate them as privileged hosts for spin currents and related phenomena. Spin pumping is an efficient mechanism for the inception of spin current and its conversion into charge current in nonmagnetic metals and semiconductors with Rashba SOC. We report on the generation at room temperature (RT) of pure spin current in nonmagnetic degenerate n -GaN:Si from a magnetic permalloy layer driven to ferromagnetic resonance (FMR) conditions. The FMR signal and the generated Hall voltages due to spin Hall effect, inverse spin Hall effect (ISHE), and spurious mechanisms are detected simultaneously. No spin-pumping-induced voltage could be measured below RT, despite the persistence of FMR signal. After eliminating the spurious (not due to ISHE) components contributing to the generated voltage, we find for n -GaN:Si a spin Hall angle θSH=3.03 ×10-3 , exceeding by one order of magnitude those reported for other semiconductors, pointing at III-nitrides as particularly efficient spin current generators.

  12. Richard L. Greene Dissertation Award in Experimental Condensed Matter or Materials Physics Talk: Towards single atom magnets

    NASA Astrophysics Data System (ADS)

    Baumann, Susanne

    Magnetic anisotropy is a fundamental property of magnetic materials that governs the stability and directionality of their magnetization. At the atomic level, magnetic anisotropy originates from anisotropy in the orbital angular momentum (L) and the spin-orbit coupling that connects the spin moment of a magnetic atom to the spatial symmetry of its ligand field environment. Generally, the ligand field, that is necessary for the anisotropy, also quenches the orbital moment and reduces the total magnetic moment of the atom to its spin component. However, careful design of the coordination geometry of a single atom can restore the orbital moment while inducing uniaxial anisotropy, as we present here for single atoms deposited on top of a thin MgO film. Scanning tunneling spectroscopy and x-ray absorption spectroscopy measurements show a large magnetic anisotropy of 19 meV for iron and 58 meV for cobalt, as well as relaxation times of many milliseconds. These results offer a strategy, based on symmetry arguments and careful tailoring of the interaction with the environment, for the rational design of nanoscopic permanent magnets and single atom magnets.

  13. 40 CFR 74.22 - Actual SO2 emissions rate.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 17 2012-07-01 2012-07-01 false Actual SO2 emissions rate. 74.22... (CONTINUED) SULFUR DIOXIDE OPT-INS Allowance Calculations for Combustion Sources § 74.22 Actual SO2 emissions... actual SO2 emissions rate shall be 1985. (2) For combustion sources that commenced operation...

  14. Actualization and the Fear of Death: Retesting an Existential Hypothesis.

    ERIC Educational Resources Information Center

    Wood, Keith; Robinson, Paul J.

    1982-01-01

    Demonstrates that within a group of highly actualized individuals, the degree to which "own death" is integrated into constructs of self is a far more powerful predictor of fear of death than actualization. Findings suggest that actualization and integration are independent in their overall effect on fear of death. (Author)

  15. Phase Transition Experimental and Theoretical Study of Micro Power Generator Supplying Source for CMOS Chip Based on Ferroelectric Ceramic Nano-Porous Material.

    PubMed

    Zhang, Zhenhai; Yu, Wei; Shi, Zhiguo; Shen, Yajing; Zhang, Donghong; Li, Kejie; Yang, Zhan

    2015-04-01

    We demonstrated both experimentally and in theory analysis and calculation that the tin-modified lead zirconate titanate nanoporous ferroelectric generator system can perform as a micro-power supplying source for CMOS chip. The ferroelectric ceramic phase transition under transverse shock wave compression can charge external storage capacitor. The nanoporous microstructure ferro-electric ceramic micro-pulsed-power system is capable of generating low output voltage pulses and supplying CMOS chip with micro power sources. We developed the methodology for theory analysis and experimental operation of the ferroelectric generator. Analysis of the porous ferroelectric ceramic material was carried out by X-ray diffractometry and X-ray photoelectron spectroscopy. Microstructures and surface morphology of porous ferroelectric ceramics samples were examined by using scanning electron microscopy. The planar shock wave experiments were conducted on a compressed-gas gun. The experimental results were in good agreement with the theory analysis. Keywords: PSZT Ferroelectric Ceramic, Shock Wave, Phase Transition, Depolarization, Micro-Power-Generator.

  16. Phase Transition Experimental and Theoretical Study of Micro Power Generator Supplying Source for CMOS Chip Based on Ferroelectric Ceramic Nano-Porous Material.

    PubMed

    Zhang, Zhenhai; Yu, Wei; Shi, Zhiguo; Shen, Yajing; Zhang, Donghong; Li, Kejie; Yang, Zhan

    2015-04-01

    We demonstrated both experimentally and in theory analysis and calculation that the tin-modified lead zirconate titanate nanoporous ferroelectric generator system can perform as a micro-power supplying source for CMOS chip. The ferroelectric ceramic phase transition under transverse shock wave compression can charge external storage capacitor. The nanoporous microstructure ferro-electric ceramic micro-pulsed-power system is capable of generating low output voltage pulses and supplying CMOS chip with micro power sources. We developed the methodology for theory analysis and experimental operation of the ferroelectric generator. Analysis of the porous ferroelectric ceramic material was carried out by X-ray diffractometry and X-ray photoelectron spectroscopy. Microstructures and surface morphology of porous ferroelectric ceramics samples were examined by using scanning electron microscopy. The planar shock wave experiments were conducted on a compressed-gas gun. The experimental results were in good agreement with the theory analysis. Keywords: PSZT Ferroelectric Ceramic, Shock Wave, Phase Transition, Depolarization, Micro-Power-Generator. PMID:26353542

  17. Comparison of Performance of Experimental and Conventional Cage Designs and Materials for 75-millimeter-bore Cylindrical Roller Bearings at High Speed

    NASA Technical Reports Server (NTRS)

    Anderson, William J; Macks, E Fred; Nemeth, Zolton N

    1954-01-01

    The results of two investigations, one to determine the relative merits of four experimental and two conventional design 75-millimeter-bore (size 215) cylindrical roller bearings and one to determine the relative merits of nodular iron and bronze as cage materials for this size and type of bearing, are presented in this report. Nine test bearings were operated over a range of dn values (product of bearing bore in mm and shaft speed in r.p.m) from 0.3 x 10(6) to 2.3 x 20(6), radial loads for 7 to 1613 pounds, and oil flows from 2 to 8 pounds per minute with a single-jet circulatory oil feed. Of the six bearings used to evaluate designs, four were experimental types with outer-race-riding cages and inner-race-guided rollers, and two were conventional types, one with outer-race-guided rollers and cage and one with inner-race-guided rollers and cage. Each of these six test bearings was equipped with a different design cage made of nodular iron. The experimental combination of an outer-race-riding cage with a straight-through outer race and inner-race-guided rollers was found to give the best over-all performance based on limiting dn values and bearing temperatures.

  18. Theoretical and Experimental Thermal Performance Analysis of Building Shell Components Containing Blown Fiber Glass Insulation Enhanced with Phase Change Material (PCM)

    SciTech Connect

    Miller, William A; Kosny, Jan; Yarbrough, David W; Childs, Phillip W; Shrestha, Som S; Atchley, Jerald Allen; Bianchi, Marcus V; Smith, John B; Fellinger, Thomas; Kossecka, Elizabeth; Lee, Edwin S

    2010-01-01

    Different types of Phase Change Materials (PCMs) have been tested as dynamic components in buildings during the last 4 decades. Most historical studies have found that PCMs enhance building energy performance. Some PCM-enhanced building materials, like PCM-gypsum boards or PCM-impregnated concretes have already found their limited applications in different countries. Today, continued improvements in building envelope technologies suggest that throughout Southern and Central US climates, residences may soon be routinely constructed with PCM in order to maximize insulation effectiveness and maintain low heating and cooling loads. The proposed paper presents experimental and numerical results from thermal performance studies. These studies focus on blown fiber glass insulation modified with a novel spray-applied microencapsulated PCM. Experimental results are reported for both laboratory-scale and full-size building elements tested in the field. In order to confirm theoretical predictions, PCM enhanced fiber glass insulation was evaluated in a guarded hot box facility to demonstrate heat flow reductions when one side of a test wall is subjected to a temperature increase. The laboratory work showed reductions in heat flow of 30% due to the presence of approximately 20 wt % PCM in the insulation. Field testing of residential attics insulated with blown fiber glass and PCM was completed in Oak Ridge, Tennessee. Experimental work was followed by detailed whole building EnergyPlus simulations in order to generate energy performance data for different US climates. In addition, a series of numerical simulations and field experiments demonstrated a potential for application of a novel PCM fiber glass insulation as enabling technology to be utilized during the attic thermal renovations.

  19. Physical properties and biological/odontogenic effects of an experimentally developed fast-setting α-tricalcium phosphate-based pulp capping material

    PubMed Central

    2014-01-01

    Background Recently, fast-setting α-tricalcium-phosphate (TCP) cement was developed for use in the pulp capping process. The aim of this study was to investigate the physical properties and biological effects of α-TCP cement in comparison with mineral trioxide aggregate (MTA). Methods We measured the setting time, pH values, compressive strength, and solubility of the two materials. We evaluated biocompatibility on the basis of cell morphology and a viability test using human dental pulp cells (hDPCs). Chemical composition of each material was analyzed by energy dispersive x-ray spectroscopic (EDS) analysis. The expression of odontogenic-related genes was evaluated by Western blotting and immunofluorescence. The calcified nodule formation was measured by Alizarin red staining. We performed the pulp capping procedure on rat teeth for histological investigation. The data were analyzed by an independent t-test for physical properties, one-way ANOVA for biological effects, and the Mann-Whitney U test for tertiary dentin formation. A P value of less than 0.05 was considered statistically significant for all tests. Results The setting time, pH values, and compressive strength of α-TCP was lower than that of MTA (P < 0.05); however, the solubility of α-TCP was higher than that of MTA (P < 0.05). The resultant cell viability observed with the two materials was similar (P > 0.05). Scanning electron microscopy (SEM) revealed that cells attached to both materials were flat and had cytoplasmic extensions. The expression of odontogenic-related markers and mineralized nodule formation were higher in the two experimental groups compared to the control group (P < 0.05). Continuous tertiary dentin was formed underneath the capping materials in all samples of the tested groups. Conclusions Our study demonstrated that the α-TCP exhibited biocompatibility and odontogenicity comparable to MTA, whereas it had a quicker setting time. PMID:25015173

  20. Experimental investigation of the effect of the material damage induced in sheet metal forming process on the service performance of 22MnB5 steel

    NASA Astrophysics Data System (ADS)

    Zhuang, Weimin; Xie, Dongxuan; Chen, Yanhong

    2016-06-01

    The use of ultra-high strength steels through sheet metal forming process offers a practical solution to the lightweight design of vehicles. However, sheet metal forming process not only produces desirable changes in material properties but also causes material damage that may adversely influence the service performance of the material formed. Thus, an investigation is conducted to experimentally quantify such influence for a commonly used steel (the 22MnB5 steel) based on the hot and cold forming processes. For each process, a number of samples are used to conduct a uniaxial tensile test to simulate the forming process. After that, some of the samples are trimmed into a standard shape and then uniaxially extended until fracture to simulate the service stage. Finally, a microstructure test is conducted to analyze the microdefects of the remaining samples. Based on the results of the first two tests, the effect of material damage on the service performance of 22MnB5 steel is analyzed. It is found that the material damages of both the hot and cold forming processes cause reductions in the service performance, such as the failure strain, the ultimate stress, the capacity of energy absorption and the ratio of residual strain. The reductions are generally lower and non-linear in the former process but higher and linear in the latter process. Additionally, it is found from the microstructure analysis that the difference in the reductions of the service performance of 22MnB5 by the two forming processes is driven by the difference in the micro damage mechanisms of the two processes. The findings of this research provide a useful reference in terms of the selection of sheet metal forming processes and the determination of forming parameters for 22MnB5.

  1. Experimental investigation of the effect of the material damage induced in sheet metal forming process on the service performance of 22MnB5 steel

    NASA Astrophysics Data System (ADS)

    Zhuang, Weimin; Xie, Dongxuan; Chen, Yanhong

    2016-07-01

    The use of ultra-high strength steels through sheet metal forming process offers a practical solution to the lightweight design of vehicles. However, sheet metal forming process not only produces desirable changes in material properties but also causes material damage that may adversely influence the service performance of the material formed. Thus, an investigation is conducted to experimentally quantify such influence for a commonly used steel (the 22MnB5 steel) based on the hot and cold forming processes. For each process, a number of samples are used to conduct a uniaxial tensile test to simulate the forming process. After that, some of the samples are trimmed into a standard shape and then uniaxially extended until fracture to simulate the service stage. Finally, a microstructure test is conducted to analyze the microdefects of the remaining samples. Based on the results of the first two tests, the effect of material damage on the service performance of 22MnB5 steel is analyzed. It is found that the material damages of both the hot and cold forming processes cause reductions in the service performance, such as the failure strain, the ultimate stress, the capacity of energy absorption and the ratio of residual strain. The reductions are generally lower and non-linear in the former process but higher and linear in the latter process. Additionally, it is found from the microstructure analysis that the difference in the reductions of the service performance of 22MnB5 by the two forming processes is driven by the difference in the micro damage mechanisms of the two processes. The findings of this research provide a useful reference in terms of the selection of sheet metal forming processes and the determination of forming parameters for 22MnB5.

  2. Experimental study on the impact-induced seismic wave propagating through granular materials: Implications for a future asteroid mission

    NASA Astrophysics Data System (ADS)

    Yasui, M.; Matsumoto, E.; Arakawa, M.; Matsue, K.; Kobayashi, N.

    2014-07-01

    Introduction: A seismic wave survey is a direct method to investigate the sub-surface structures of solid bodies, so we measured and analyzed these seismic waves propagating through these interiors. Earthquake and Moonquake are the only two phenomena that have been observed to explore these interiors until now, while the future surveys on the other bodies, (solid planets and/or asteroids) are now planned. To complete a seismic wave survey during the mission period, an artificial method that activates the seismic wave is necessary and one candidate is a projectile collision on the target body. However, to utilize the artificial seismic wave generated on the target body, the relationship between the impact energy and the amplitude and the decay process of the seismic wave should be examined. If these relationships are clarified, we can estimate the required sensitivity of seismometers installed on the target body and the possible distance from the seismic origin measurable for the seismometer. Furthermore, if we can estimate the impact energy from the observed seismic wave, we expect to be able to estimate the impact flux of impactors that collided on the target body. McGarr et al. (1969) did impact experiments by using the lexan projectile and two targets, quartz sand and sand bonded by epoxy cement, at 0.8-7 km/s. They found a difference of seismic wave properties between the two targets, and calculated the conversion efficiency to discuss the capability of detection of seismic waves on the Moon. However, they did not examine the excitation and propagation properties of the seismic waves in detail. In this study, we carried out impact experiments in the laboratory to observe the seismic waves by accelerometers, and examined the effects of projectile properties on the excitation and propagation properties of the seismic waves. Experimental methods: We made impact experiments by using a one-stage gas gun at Kobe University. Projectiles were a polycarbonate cylinder

  3. X-ray diffraction-based electronic structure calculations and experimental x-ray analysis for medical and materials applications

    NASA Astrophysics Data System (ADS)

    Mahato, Dip Narayan

    This thesis includes x-ray experiments for medical and materials applications and the use of x-ray diffraction data in a first-principles study of electronic structures and hyperfine properties of chemical and biological systems. Polycapillary focusing lenses were used to collect divergent x rays emitted from conventional x-ray tubes and redirect them to form an intense focused beam. These lenses are routinely used in microbeam x-ray fluorescence analysis. In this thesis, their potential application to powder diffraction and focused beam orthovoltage cancer therapy has been investigated. In conventional x-ray therapy, very high energy (˜ MeV) beams are used, partly to reduce the skin dose. For any divergent beam, the dose is necessarily highest at the entry point, and decays exponentially into the tissue. To reduce the skin dose, high energy beams, which have long absorption lengths, are employed, and rotated about the patient to enter from different angles. This necessitates large expensive specialized equipment. A focused beam could concentrate the dose within the patient. Since this is inherently skin dose sparing, lower energy photons could be employed. A primary concern in applying focused beams to therapy is whether the focus would be maintained despite Compton scattering within the tissue. To investigate this, transmission and focal spot sizes as a function of photon energy of two polycapillary focusing lenses were measured. The effects of tissue-equivalent phantoms of different thicknesses on the focal spot size were studied. Scatter fraction and depth dose were calculated. For powder diffraction, the polycapillary optics provide clean Gaussian peaks, which result in angular resolution that is much smaller than the peak width due to the beam convergence. Powder diffraction (also called coherent scatter) without optics can also be used to distinguish between tissue types that, because they have different nanoscale structures, scatter at different angles

  4. An experimental investigation of using carbon foam-PCM-MWCNTs composite materials for thermal management of electronic devices under pulsed power modes

    NASA Astrophysics Data System (ADS)

    Alshaer, W. G.; Rady, M. A.; Nada, S. A.; Palomo Del Barrio, Elena; Sommier, Alain

    2016-05-01

    The present article reports on a detailed experimental investigation of using carbon foam-PCM-MWCNTs composite materials for thermal management (TM) of electronic devices subjected to pulsed power. The TM module was fabricated by infiltrating paraffin wax (RT65) as a phase change material (PCM) and multi walled carbon nanotubes (MWCNTs) as a thermal conductivity enhancer in a carbon foam as a base structure. Two carbon foam materials of low and high values of thermal conductivities, CF20 and KL1-250 (3.1 and 40 W/m K), were tested as a base structure for the TM modules. Tests were conducted at different power intensities and power cycling/loading modes. Results showed that for all power varying modes and all carbon foams, the infiltration of RT65 into carbon foam reduces the temperature of TM module and results in damping the temperature spikes height. Infiltration of MWCNTS into RT65 further improves the effectiveness of TM module. Temperature damping was more pronounced in stand-alone pulsed power cycles as compared to pulsed power spikes modes. The effectiveness of inclusion of RT65 and RT65/MWCNTs in damping the temperature spikes height is remarkable in TM modules based on KL1-250 as compared to CF-20.

  5. [Psychoactive plant species--actual list of plants prohibited in Poland].

    PubMed

    Simonienko, Katarzyna; Waszkiewicz, Napoleon; Szulc, Agata

    2013-01-01

    According to the Act on Counteracting Drug Addiction (20-th of March, 2009, Dz. U. Nr 63 poz. 520.) the list of federally prohibited plants in Poland was expanded to include 16 new species. Until that time the only illegal plant materials were cannabis, papaver, coca and most of their products. The actual list of herbal narcotics includes species which significantly influence on the central nervous system work but which are rarely described in the national literature. The plants usually come from distant places, where--among primeval cultures--are used for ritual purposes. In our civilization the plants are usually used experimentally, recreationally or to gain particular narcotic effects. The results of the consumption vary: they can be specific or less typical, imitate other substances intake, mental disorders or different pathological states. The plant active substances can interact with other medicaments, be toxic to internal organs, cause serious threat to health or even death. This article describes the sixteen plant species, which are now prohibited in Poland, their biochemical ingredients and their influence on the human organism.

  6. Experimental Investigation of Magnetic Superconducting and other Phase Transitions in Novel f-Electron Materials at Ultra-high Pressures using Designer Diamond Anvils

    SciTech Connect

    Maple, M. Brian; Jeffries, Jason R.; Ho, Pei-Chun; Butch, Nicholas P.

    2004-09-01

    Pressure is often used as a controlled parameter for the investigation of condensed matter systems. In particular, pressure experiments can provide valuable information into the nature of superconductivity, magnetism, and the coexistence of these two phenomena. Some f-electron, heavy-fermion materials display interesting and novel behavior at moderately low pressures achievable with conventional experimental techniques; however, a growing number of condensed matter systems require ultrahigh pressure techniques, techniques that generate significantly higher pressures than conventional methods, to sufficiently explore their important properties. To that end, we have been funded to develop an ultrahigh pressure diamond anvil cell facility at the University of California, San Diego (UCSD) in order to investigate superconductivity, magnetism, non-Fermi liquid behavior, and other phenomena. Our goals for the first year of this grant were as follows: (a) set up and test a suitable refrigerator; (b) set up a laser and spectrometer fluorescence system to determine the pressure within the diamond anvil cell; (c) perform initial resistivity measurements at moderate pressures from room temperature to liquid helium temperatures ({approx}1K); (d) investigate f-electron materials within our current pressure capabilities to find candidate materials for high-pressure studies. During the past year, we have ordered almost all the components required to set up a diamond anvil cell facility at UCSD, we have received and implemented many of the components that have been ordered, we have performed low pressure research on several materials, and we have engaged in a collaborative effort with Sam Weir at Lawrence Livermore National Lab (LLNL) to investigate Au4V under ultrahigh pressure in a designer diamond anvil cell (dDAC). This report serves to highlight the progress we have made towards developing an ultrahigh pressure research facility at UCSD, the research performed in the past year

  7. Toxicological and chemical characterization of the process stream materials and gas combustion products of an experimental low-Btu coal gasifier

    SciTech Connect

    Benson, J.M.; Hanson, R.L.; Royer, R.E.; Clark, C.R.; Henderson, R.F.

    1984-04-01

    The process gas stream of an experimental pressurized McDowell-Wellman stirred-bed low-Btu coal gasifier, and combustion products of the clean gas were characterized as to their mutagenic properties and chemical composition. Samples of aerosol droplets condensed from the gas were obtained at selected positions along the process stream using a condenser train. Mutagenicity was assessed using the Ames Salmonella mammalian microsome mutagenicity assay (TA98, with and without rat liver S9). All materials required metabolic activation to be mutagenic. Droplets condensed from gas had a specific mugtagenicity of 6.7 reverants/..mu..g (50,000 revertants/liter of raw gas). Methylnaphthalene, phenanthrene, chrysene, and nitrogen-containing compounds were positively identified in a highly mutagenic fraction of raw gas condensate. While gas cleanup by the humidifier-tar trap system and Venturi scrubber led to only a small reduction in specific mutagenicity of the cooled process stream material (4.1 revertants/..mu..g), a significant overall reduction in mutagenicity was achieved (to 2200 reverants/liter) due to a substantial reduction in the concentration of material in the gas. By the end of gas cleanup, gas condensates had no detectable mutagenic activity. Condensates of combustion product gas, which contained several polycyclic aromatic compounds, had a specific mutagenicity of 1.1 revertants/..mu..g (4.0 revertants/liter). Results indicate that the process stream material is potentially toxic and that care should be taken to limit exposure of workers to the aerosolized tars emitted in fugitive emissions. Health risks to general population resulting from exposure to gas combustion products are expected to be minimal. 28 references.

  8. Experimental Design for a Macrofoam-Swab Study Relating the Recovery Efficiency and False Negative Rate to Low Concentrations of Two Bacillus anthracis Surrogates on Four Surface Materials

    SciTech Connect

    Piepel, Gregory F.; Hutchison, Janine R.

    2014-12-05

    This report describes the experimental design for a laboratory study to quantify the recovery efficiencies and false negative rates of a validated, macrofoam-swab sampling method for low concentrations of Bacillus anthracis Sterne (BAS) and Bacillus atrophaeus (BG) spores on four surface materials (stainless steel, glass, vinyl tile, plastic light cover panel). Two analytical methods (culture and polymerase chain reaction) will be used. Only one previous study has investigated how the false negative rate depends on test factors. The surrogates BAS and BG have not been tested together in the same study previously. Hence, this study will provide for completing gaps in the available information on the performance of macrofoam-swab sampling at low concentrations.

  9. Experimental Design for a Macrofoam Swab Study Relating the Recovery Efficiency and False Negative Rate to Low Concentrations of Two Bacillus anthracis Surrogates on Four Surface Materials

    SciTech Connect

    Piepel, Gregory F.; Hutchison, Janine R.

    2014-04-16

    This report describes the experimental design for a laboratory study to quantify the recovery efficiencies and false negative rates of a validated, macrofoam swab sampling method for low concentrations of Bacillus anthracis Sterne (BAS) and Bacillus atrophaeus (BG) spores on four surface materials (stainless steel, glass, vinyl tile, plastic light cover panel). Two analytical methods (plating/counting and polymerase chain reaction) will be used. Only one previous study has investigated false negative as a function of affecting test factors. The surrogates BAS and BG have not been tested together in the same study previously. Hence, this study will provide for completing gaps in the available information on the performance of macrofoam swab sampling at low concentrations.

  10. MELCOR model for an experimental 17x17 spent fuel PWR assembly.

    SciTech Connect

    Cardoni, Jeffrey

    2010-11-01

    A MELCOR model has been developed to simulate a pressurized water reactor (PWR) 17 x 17 assembly in a spent fuel pool rack cell undergoing severe accident conditions. To the extent possible, the MELCOR model reflects the actual geometry, materials, and masses present in the experimental arrangement for the Sandia Fuel Project (SFP). The report presents an overview of the SFP experimental arrangement, the MELCOR model specifications, demonstration calculation results, and the input model listing.

  11. Beaked whales respond to simulated and actual navy sonar.

    PubMed

    Tyack, Peter L; Zimmer, Walter M X; Moretti, David; Southall, Brandon L; Claridge, Diane E; Durban, John W; Clark, Christopher W; D'Amico, Angela; DiMarzio, Nancy; Jarvis, Susan; McCarthy, Elena; Morrissey, Ronald; Ward, Jessica; Boyd, Ian L

    2011-03-14

    Beaked whales have mass stranded during some naval sonar exercises, but the cause is unknown. They are difficult to sight but can reliably be detected by listening for echolocation clicks produced during deep foraging dives. Listening for these clicks, we documented Blainville's beaked whales, Mesoplodon densirostris, in a naval underwater range where sonars are in regular use near Andros Island, Bahamas. An array of bottom-mounted hydrophones can detect beaked whales when they click anywhere within the range. We used two complementary methods to investigate behavioral responses of beaked whales to sonar: an opportunistic approach that monitored whale responses to multi-day naval exercises involving tactical mid-frequency sonars, and an experimental approach using playbacks of simulated sonar and control sounds to whales tagged with a device that records sound, movement, and orientation. Here we show that in both exposure conditions beaked whales stopped echolocating during deep foraging dives and moved away. During actual sonar exercises, beaked whales were primarily detected near the periphery of the range, on average 16 km away from the sonar transmissions. Once the exercise stopped, beaked whales gradually filled in the center of the range over 2-3 days. A satellite tagged whale moved outside the range during an exercise, returning over 2-3 days post-exercise. The experimental approach used tags to measure acoustic exposure and behavioral reactions of beaked whales to one controlled exposure each of simulated military sonar, killer whale calls, and band-limited noise. The beaked whales reacted to these three sound playbacks at sound pressure levels below 142 dB re 1 µPa by stopping echolocation followed by unusually long and slow ascents from their foraging dives. The combined results indicate similar disruption of foraging behavior and avoidance by beaked whales in the two different contexts, at exposures well below those used by regulators to define

  12. Beaked Whales Respond to Simulated and Actual Navy Sonar

    PubMed Central

    Tyack, Peter L.; Zimmer, Walter M. X.; Moretti, David; Southall, Brandon L.; Claridge, Diane E.; Durban, John W.; Clark, Christopher W.; D'Amico, Angela; DiMarzio, Nancy; Jarvis, Susan; McCarthy, Elena; Morrissey, Ronald; Ward, Jessica; Boyd, Ian L.

    2011-01-01

    Beaked whales have mass stranded during some naval sonar exercises, but the cause is unknown. They are difficult to sight but can reliably be detected by listening for echolocation clicks produced during deep foraging dives. Listening for these clicks, we documented Blainville's beaked whales, Mesoplodon densirostris, in a naval underwater range where sonars are in regular use near Andros Island, Bahamas. An array of bottom-mounted hydrophones can detect beaked whales when they click anywhere within the range. We used two complementary methods to investigate behavioral responses of beaked whales to sonar: an opportunistic approach that monitored whale responses to multi-day naval exercises involving tactical mid-frequency sonars, and an experimental approach using playbacks of simulated sonar and control sounds to whales tagged with a device that records sound, movement, and orientation. Here we show that in both exposure conditions beaked whales stopped echolocating during deep foraging dives and moved away. During actual sonar exercises, beaked whales were primarily detected near the periphery of the range, on average 16 km away from the sonar transmissions. Once the exercise stopped, beaked whales gradually filled in the center of the range over 2–3 days. A satellite tagged whale moved outside the range during an exercise, returning over 2–3 days post-exercise. The experimental approach used tags to measure acoustic exposure and behavioral reactions of beaked whales to one controlled exposure each of simulated military sonar, killer whale calls, and band-limited noise. The beaked whales reacted to these three sound playbacks at sound pressure levels below 142 dB re 1 µPa by stopping echolocation followed by unusually long and slow ascents from their foraging dives. The combined results indicate similar disruption of foraging behavior and avoidance by beaked whales in the two different contexts, at exposures well below those used by regulators to define

  13. Analytical, Numerical, and Experimental Investigation on a Non-Contact Method for the Measurements of Creep Properties of Ultra-High-Temperature Materials

    NASA Technical Reports Server (NTRS)

    Lee, Jonghyun; Hyers, Robert W.; Rogers, Jan R.; Rathz, Thomas J.; Choo, Hahn; Liaw, Peter

    2006-01-01

    Responsive access to space requires re-use of components such as rocket nozzles that operate at extremely high temperatures. For such applications, new ultra-hightemperature materials that can operate over 2,000 C are required. At the temperatures higher than the fifty percent of the melting temperature, the characterization of creep properties is indispensable. Since conventional methods for the measurement of creep is limited below 1,700 C, a new technique that can be applied at higher temperatures is strongly demanded. This research develops a non-contact method for the measurement of creep at the temperatures over 2,300 C. Using the electrostatic levitator in NASA MSFC, a spherical sample was rotated to cause creep deformation by centrifugal acceleration. The deforming sample was captured with a digital camera and analyzed to measure creep deformation. Numerical and analytical analyses have also been conducted to compare the experimental results. Analytical, numerical, and experimental results showed a good agreement with one another.

  14. Experimental characterization and macro-modeling of mechanical strength of multi-sheets and multi-materials spot welds under pure and mixed modes I and II

    NASA Astrophysics Data System (ADS)

    Chtourou, Rim; Haugou, Gregory; Leconte, Nicolas; Zouari, Bassem; Chaari, Fahmi; Markiewicz, Eric

    2015-09-01

    Resistance Spot Welding (RSW) of multiple sheets with multiple materials are increasingly realized in the automotive industry. The mechanical strength of such new generation of spot welded assemblies is not that much dealt with. This is true in particular for experiments dedicated to investigate the mechanical strength of spot weld made by multi sheets of different grades, and their macro modeling in structural computations. Indeed, the most published studies are limited to two sheet assemblies. Therefore, in the first part of this work an advanced experimental set-up with a reduced mass is proposed to characterize the quasi-static and dynamic mechanical behavior and rupture of spot weld made by several sheets of different grades. The proposed device is based on Arcan test, the plates contribution in the global response is, thus, reduced. Loading modes I/II are, therefore, combined and well controlled. In the second part a simplified spot weld connector element (macroscopic modeling) is proposed to describe the nonlinear response and rupture of this new generation of spot welded assemblies. The weld connector model involves several parameters to be set. The remaining parameters are finally identified through a reverse engineering approach using mechanical responses of experimental tests presented in the first part of this work.

  15. Experimental study of a passive thermal management system for high-powered lithium ion batteries using porous metal foam saturated with phase change materials

    NASA Astrophysics Data System (ADS)

    Li, W. Q.; Qu, Z. G.; He, Y. L.; Tao, Y. B.

    2014-06-01

    A highly efficient thermal strategy to manage a high-powered Li-ion battery package within the required safe temperature range is of great demand for electric vehicles (EVs) applications. A sandwiched cooling structure using copper metal foam saturated with phase change materials was designed. The thermal efficiency of the system was experimentally evaluated and compared with two control cases: a cooling mode with pure phase change materials and an air-cooling mode. The results showed that the thermal management with air natural convection cannot fulfill the safety demand of the Li-ion battery. The use of pure PCM can dramatically reduce the surface temperature and maintain the temperature within an allowable range due to the latent heat absorption and the natural convection of the melted PCM during the melting process. The foam-paraffin composite further reduced the battery's surface temperature and improved the uniformity of the temperature distribution caused by the improvement of the effective thermal conductivity. Additionally, the battery surface temperature increased with an increase in the porosity and the pore density of the metal foam.

  16. [Regeneration processes in bone defects after implantation of composite material of different density of polylactide origin filled with HAP (experimental-morphological study)].

    PubMed

    Kulakov, A A; Grigor'ian, A S; Krotova, L I; Popov, V K; Volozhin, A I; Losev, V F

    2009-01-01

    In experimental-morphological study on 6 dogs the dynamics of regenerate formation in ulna and mandible defects after implantation in them composite material of different density (0.46-0.50 and 0.38-0.42 g/cm(3)) of polylactide (PL) origin filled with HAP was followed at the terms of 6 and 9 months. Histologic study and structural determinant distribution analysis in the content of regenerate showed that optimal results according to the bone defect substitution by bone regenerate criterion at 9th month of the experiment were received after composite material from PL and HAP with the density of 0.38-0.42 g/cm(3) implantation. Newly formed trabecular bone tissue was seen in the regenerate and as well as strong tendency for bone matrix maturation. It was confirmed by the appearance of lamellar structures in newly formed bone trabecules situated in peripheral zones of bone defect. In bone mandible defects the substitution process of the implants from PL with HAP by the bone tissue was much slower than in ulna defects.

  17. Experimental Investigation of Magnetic, Superconducting, and other Phase Transitions in novel F-Electron Materials at Ultra-high Pressures - Final Progress Report

    SciTech Connect

    Maple, Brian; Jeffires, Jason

    2006-07-28

    This grant, entitled “Experimental investigation of magnetic, superconducting and other phase transitions in novel f-electron materials at ultrahigh pressures,” spanned the funding period from May 1st, 2003 until April 30th, 2006. The major goal of this grant was to develop and utilize an ultrahigh pressure facility—capable of achieving very low temperatures, high magnetic fields, and extreme pressures as well as providing electrical resistivity, ac susceptibility, and magnetization measurement capabilities under pressure—for the exploration of magnetic, electronic, and structural phases and any corresponding interactions between these states in novel f-electron materials. Realizing this goal required the acquisition, development, fabrication, and implementation of essential equipment, apparatuses, and techniques. The following sections of this report detail the establishment of an ultrahigh pressure facility (Section 1) and measurements performed during the funding period (Section 2), as well as summarize the research project (Section 3), project participants and their levels of support (Section 4), and publications and presentations (Section 5).

  18. Relationship between perceived and actual motor competence among college students.

    PubMed

    Wang, Jianyu; Liu, Wenhao; Bian, Wei

    2013-02-01

    The relationship between perceived and actual motor competence was examined among college students. Participants were 114 college students (55 men, 59 women; M age = 22.3 yr., SD = 3.9). All participants completed a short survey on perception of motor competence in basketball and took a Control Basketball Dribble Test to assess their actual motor skill. Perceived motor competence in basketball was significantly related to basketball dribbling performance. Given the positive relationship between actual motor competence and perceived competence, enhancing an individual's actual motor competence may contribute to their perceived competence, which may improve an individual's physical activity participation.

  19. Computational simulation of coupled material degradation processes for probabilistic lifetime strength of aerospace materials

    NASA Technical Reports Server (NTRS)

    Boyce, Lola; Bast, Callie C.

    1992-01-01

    The research included ongoing development of methodology that provides probabilistic lifetime strength of aerospace materials via computational simulation. A probabilistic material strength degradation model, in the form of a randomized multifactor interaction equation, is postulated for strength degradation of structural components of aerospace propulsion systems subjected to a number of effects or primative variables. These primative variable may include high temperature, fatigue or creep. In most cases, strength is reduced as a result of the action of a variable. This multifactor interaction strength degradation equation has been randomized and is included in the computer program, PROMISS. Also included in the research is the development of methodology to calibrate the above described constitutive equation using actual experimental materials data together with linear regression of that data, thereby predicting values for the empirical material constraints for each effect or primative variable. This regression methodology is included in the computer program, PROMISC. Actual experimental materials data were obtained from the open literature for materials typically of interest to those studying aerospace propulsion system components. Material data for Inconel 718 was analyzed using the developed methodology.

  20. Self-Actualization Effects Of A Marathon Growth Group

    ERIC Educational Resources Information Center

    Jones, Dorothy S.; Medvene, Arnold M.

    1975-01-01

    This study examined the effects of a marathon group experience on university student's level of self-actualization two days and six weeks after the experience. Gains in self-actualization as a result of marathon group participation depended upon an individual's level of ego strength upon entering the group. (Author)

  1. The Self-Actualization of Polk Community College Students.

    ERIC Educational Resources Information Center

    Pearsall, Howard E.; Thompson, Paul V., Jr.

    This article investigates the concept of self-actualization introduced by Abraham Maslow (1954). A summary of Maslow's Needs Hierarchy, along with a description of the characteristics of the self-actualized person, is presented. An analysis of humanistic education reveals it has much to offer as a means of promoting the principles of…

  2. Depression and Self-Actualization in Gifted Adolescents.

    ERIC Educational Resources Information Center

    Berndt, David J.; And Others

    1982-01-01

    Investigated the relationship between depressive affect and self-actualization in gifted adolescents (N=248). Found that gifted students who were not self-actualizing types were more depressed; and guilt, low self-esteem, learned helplessness, and cognitive difficulty were important symptoms. Gifted adolescents tended to be more socially…

  3. 24 CFR 200.96 - Certificates of actual cost.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Endorsement Generally Applicable to Multifamily and Health Care Facility Mortgage Insurance Programs; and Continuing Eligibility Requirements for Existing Projects Cost Certification § 200.96 Certificates of actual... 24 Housing and Urban Development 2 2013-04-01 2013-04-01 false Certificates of actual cost....

  4. 24 CFR 200.96 - Certificates of actual cost.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Endorsement Generally Applicable to Multifamily and Health Care Facility Mortgage Insurance Programs; and Continuing Eligibility Requirements for Existing Projects Cost Certification § 200.96 Certificates of actual... 24 Housing and Urban Development 2 2011-04-01 2011-04-01 false Certificates of actual cost....

  5. 24 CFR 200.96 - Certificates of actual cost.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Endorsement Generally Applicable to Multifamily and Health Care Facility Mortgage Insurance Programs; and Continuing Eligibility Requirements for Existing Projects Cost Certification § 200.96 Certificates of actual... 24 Housing and Urban Development 2 2014-04-01 2014-04-01 false Certificates of actual cost....

  6. 24 CFR 200.96 - Certificates of actual cost.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Endorsement Generally Applicable to Multifamily and Health Care Facility Mortgage Insurance Programs; and Continuing Eligibility Requirements for Existing Projects Cost Certification § 200.96 Certificates of actual... 24 Housing and Urban Development 2 2012-04-01 2012-04-01 false Certificates of actual cost....

  7. 24 CFR 200.96 - Certificates of actual cost.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Endorsement Generally Applicable to Multifamily and Health Care Facility Mortgage Insurance Programs; and Continuing Eligibility Requirements for Existing Projects Cost Certification § 200.96 Certificates of actual... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Certificates of actual cost....

  8. SELF-ACTUALIZATION AND THE UTILIZATION OF TALENT.

    ERIC Educational Resources Information Center

    FRENCH, JOHN R.P.; MILLER, DANIEL R.

    THIS STUDY ATTEMPTED (1) TO DEVELOP A THEORY OF THE CAUSES AND CONSEQUENCES OF SELF-ACTUALIZATION AS RELATED TO THE UTILIZATION OF TALENT, (2) TO FIT THE THEORY TO EXISTING DATA, AND (3) TO PLAN ONE OR MORE RESEARCH PROJECTS TO TEST THE THEORY. TWO ARTICLES ON IDENTITY AND MOTIVATION AND SELF-ACTUALIZATION AND SELF-IDENTITY THEORY REPORTED THE…

  9. Facebook as a Library Tool: Perceived vs. Actual Use

    ERIC Educational Resources Information Center

    Jacobson, Terra B.

    2011-01-01

    As Facebook has come to dominate the social networking site arena, more libraries have created their own library pages on Facebook to create library awareness and to function as a marketing tool. This paper examines reported versus actual use of Facebook in libraries to identify discrepancies between intended goals and actual use. The results of a…

  10. A Study of Self-Actualization and Facilitative Communication.

    ERIC Educational Resources Information Center

    Omizo, Michael M.

    1981-01-01

    Examined the relationship between self-actualization measures and ability in facilitative communication of trainees from counseling, social work, and psychology programs to determine if differences existed between the three groups. Self-actualization indexes were significantly correlated with ability in facilitative communication. (RC)

  11. 26 CFR 1.962-3 - Treatment of actual distributions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 10 2013-04-01 2013-04-01 false Treatment of actual distributions. 1.962-3... TAX (CONTINUED) INCOME TAXES (CONTINUED) Controlled Foreign Corporations § 1.962-3 Treatment of actual... a foreign corporation. (ii) Treatment of section 962 earnings and profits under § 1.959-3....

  12. Experimental Investigation of Magnetic Superconducting, and other Phase Transitions in Novel f-Electron Materials at Ultra-high Pressures Using Designer Diamond Anvils

    SciTech Connect

    Maple, M. Brian

    2005-09-13

    Pressure is a powerful control parameter, owing to its ability to affect crystal and electronic structure without introducing defects, for the investigation of condensed matter systems. Some f-electron, heavy-fermion materials display interesting and novel behavior when exposed to pressures achievable with conventional experimental techniques; however, a growing number of condensed matter systems require extreme conditions such as ultrahigh pressures, high magnetic fields, and ultralow temperatures to sufficiently explore the important properties. To that end, we have been funded to develop an ultrahigh pressure facility at the University of California, San Diego (UCSD) in order to investigate superconductivity, magnetism, non-Fermi liquid behavior, and other phenomena under extreme conditions. Our goals for the second year of this grant were as follows: (a) perform electrical resistivity measurements on novel samples at a myriad of pressures using conventional piston-cylinder techniques, Bridgman anvil techniques, and diamond anvil cell technology; (b) install, commission, and operate an Oxford Kelvinox MX-100 dilution refrigerator for access to ultralow temperatures and high magnetic fields. (c) continue the development of diamond anvil cell (DAC) technology. During the past year, we have successfully installed the Oxford Kelvinox MX-100 dilution refrigerator and verified its operability down to 12 mK. We have begun an experimental program to systematically investigate the f-electron compound URu2Si2 under pressure and in the presence of magnetic fields. We have also continued our collaborative work with Sam Weir at Lawrence Livermore National Laboratory (LLNL) on Au4V and implemented a new corollary study on Au1-xVx using ultrahigh pressures. We have continued developing our DAC facility by designing and constructing an apparatus for in situ pressure measurement as well as designing high pressure cells. This report serves to highlight the progress we have made

  13. An evaluation of five different dressing materials on split-thickness skin graft donor site and full-thickness cutaneous wounds: an experimental study.

    PubMed

    Uraloğlu, Muhammet; Livaoğlu, Murat; Agdoğan, Özgür; Mungan, Sevdegül; Alhan, Etem; Karaçal, Naci

    2014-02-01

    The objective of this study was to investigate the healing effect of five different products on split-thickness skin graft (STSG) donor sites and full-thickness cutaneous wounds (FTCWs) using an occlusive dressing model. Six groups were included: 1 control and 5 experimental groups, with a total of 24 rats, using an occlusive dressing model. STSG donor sites and FTCWs were established in two separate areas, to the right and left on the animals' backs. Wound sites were dressed with one of the following materials: fine mesh gauze, microporous polysaccharide hemosphere (MPH), clinoptilolite, alginate, hydrogel or biosynthetic wound dressing (Biobran(®) ). These materials were compared in terms of healing rate, healing quality and histopathological findings. Occlusive dressings were applied to each wound on days 0, 3, 5, 7, 10 and 14. Area measurements were taken using images of each dressing. The alginate and clinoptilolite groups gave the best healing rate results for both STSG donor sites (P = 0·003) and FTCWs (P = 0·003). MPH came third in each group. The alginate group produced better results in terms of healing quality criteria, followed by hydrogel, MPH, clinoptilolite and Biobran(®) , in that order. Statistically significant results were obtained in all groups compared to the control group (P < 0·0007). Rapid and good healing quality for both the STSG donor sites and FTCWs were obtained with alginate. Healing with clinoptilolite and MPH was rapid, but poor quality, while slower but good healing quality was obtained with hydrogel. Slower and worse quality healing was obtained with Biobran(®) . PMID:22943661

  14. Comparison of predicted and actual consequences of missense mutations.

    PubMed

    Miosge, Lisa A; Field, Matthew A; Sontani, Yovina; Cho, Vicky; Johnson, Simon; Palkova, Anna; Balakishnan, Bhavani; Liang, Rong; Zhang, Yafei; Lyon, Stephen; Beutler, Bruce; Whittle, Belinda; Bertram, Edward M; Enders, Anselm; Goodnow, Christopher C; Andrews, T Daniel

    2015-09-15

    Each person's genome sequence has thousands of missense variants. Practical interpretation of their functional significance must rely on computational inferences in the absence of exhaustive experimental measurements. Here we analyzed the efficacy of these inferences in 33 de novo missense mutations revealed by sequencing in first-generation progeny of N-ethyl-N-nitrosourea-treated mice, involving 23 essential immune system genes. PolyPhen2, SIFT, MutationAssessor, Panther, CADD, and Condel were used to predict each mutation's functional importance, whereas the actual effect was measured by breeding and testing homozygotes for the expected in vivo loss-of-function phenotype. Only 20% of mutations predicted to be deleterious by PolyPhen2 (and 15% by CADD) showed a discernible phenotype in individual homozygotes. Half of all possible missense mutations in the same 23 immune genes were predicted to be deleterious, and most of these appear to become subject to purifying selection because few persist between separate mouse substrains, rodents, or primates. Because defects in immune genes could be phenotypically masked in vivo by compensation and environment, we compared inferences by the same tools with the in vitro phenotype of all 2,314 possible missense variants in TP53; 42% of mutations predicted by PolyPhen2 to be deleterious (and 45% by CADD) had little measurable consequence for TP53-promoted transcription. We conclude that for de novo or low-frequency missense mutations found by genome sequencing, half those inferred as deleterious correspond to nearly neutral mutations that have little impact on the clinical phenotype of individual cases but will nevertheless become subject to purifying selection.

  15. Comparison of predicted and actual consequences of missense mutations

    PubMed Central

    Miosge, Lisa A.; Field, Matthew A.; Sontani, Yovina; Cho, Vicky; Johnson, Simon; Palkova, Anna; Balakishnan, Bhavani; Liang, Rong; Zhang, Yafei; Lyon, Stephen; Beutler, Bruce; Whittle, Belinda; Bertram, Edward M.; Enders, Anselm; Goodnow, Christopher C.; Andrews, T. Daniel

    2015-01-01

    Each person’s genome sequence has thousands of missense variants. Practical interpretation of their functional significance must rely on computational inferences in the absence of exhaustive experimental measurements. Here we analyzed the efficacy of these inferences in 33 de novo missense mutations revealed by sequencing in first-generation progeny of N-ethyl-N-nitrosourea–treated mice, involving 23 essential immune system genes. PolyPhen2, SIFT, MutationAssessor, Panther, CADD, and Condel were used to predict each mutation’s functional importance, whereas the actual effect was measured by breeding and testing homozygotes for the expected in vivo loss-of-function phenotype. Only 20% of mutations predicted to be deleterious by PolyPhen2 (and 15% by CADD) showed a discernible phenotype in individual homozygotes. Half of all possible missense mutations in the same 23 immune genes were predicted to be deleterious, and most of these appear to become subject to purifying selection because few persist between separate mouse substrains, rodents, or primates. Because defects in immune genes could be phenotypically masked in vivo by compensation and environment, we compared inferences by the same tools with the in vitro phenotype of all 2,314 possible missense variants in TP53; 42% of mutations predicted by PolyPhen2 to be deleterious (and 45% by CADD) had little measurable consequence for TP53-promoted transcription. We conclude that for de novo or low-frequency missense mutations found by genome sequencing, half those inferred as deleterious correspond to nearly neutral mutations that have little impact on the clinical phenotype of individual cases but will nevertheless become subject to purifying selection. PMID:26269570

  16. Comparison of predicted and actual consequences of missense mutations.

    PubMed

    Miosge, Lisa A; Field, Matthew A; Sontani, Yovina; Cho, Vicky; Johnson, Simon; Palkova, Anna; Balakishnan, Bhavani; Liang, Rong; Zhang, Yafei; Lyon, Stephen; Beutler, Bruce; Whittle, Belinda; Bertram, Edward M; Enders, Anselm; Goodnow, Christopher C; Andrews, T Daniel

    2015-09-15

    Each person's genome sequence has thousands of missense variants. Practical interpretation of their functional significance must rely on computational inferences in the absence of exhaustive experimental measurements. Here we analyzed the efficacy of these inferences in 33 de novo missense mutations revealed by sequencing in first-generation progeny of N-ethyl-N-nitrosourea-treated mice, involving 23 essential immune system genes. PolyPhen2, SIFT, MutationAssessor, Panther, CADD, and Condel were used to predict each mutation's functional importance, whereas the actual effect was measured by breeding and testing homozygotes for the expected in vivo loss-of-function phenotype. Only 20% of mutations predicted to be deleterious by PolyPhen2 (and 15% by CADD) showed a discernible phenotype in individual homozygotes. Half of all possible missense mutations in the same 23 immune genes were predicted to be deleterious, and most of these appear to become subject to purifying selection because few persist between separate mouse substrains, rodents, or primates. Because defects in immune genes could be phenotypically masked in vivo by compensation and environment, we compared inferences by the same tools with the in vitro phenotype of all 2,314 possible missense variants in TP53; 42% of mutations predicted by PolyPhen2 to be deleterious (and 45% by CADD) had little measurable consequence for TP53-promoted transcription. We conclude that for de novo or low-frequency missense mutations found by genome sequencing, half those inferred as deleterious correspond to nearly neutral mutations that have little impact on the clinical phenotype of individual cases but will nevertheless become subject to purifying selection. PMID:26269570

  17. Role of the metal cation types around VO4 groups on the nonlinear optical behavior of materials: experimental and theoretical analysis.

    PubMed

    Su, Xin; Yang, Zhihua; Han, Guopeng; Wang, Ying; Wen, Ming; Pan, Shilie

    2016-09-28

    In order to explore new NLO crystals with superior performances, it is greatly desirable to understand the intrinsic relationship between the macroscopic optical properties and microscopic structural features in crystals. A novel mechanism for nonlinear optical (NLO) effects of vanadate crystals, Li3VO4, KCd4(VO4)3 and Ca3(VO4)2 with distorted (VO4)(3-) groups, has been investigated. Experiments related to the synthesis and structures were determined. In addition, infrared and UV-Vis-NIR diffuse reflectance spectroscopy, as well as electronic band structure calculations, were performed on the reported materials. A comprehensive analysis for the structure-property relationship is given by combining the experimental measurements, the electronic structure calculations and the SHG-weighted electron density to the linear and NLO properties. It was found that the contribution of the (VO4)(3-) anionic group to the second harmonic generation (SHG) response was the dominant anionic group, which plays a vital role to the SHG effects in Li3VO4, KCd4(VO4)3 and Ca3(VO4)2. It was also concluded that the metal cation types and coordination around VO4 groups, the distorted and parallel oriented VO4 tetrahedron decided the SHG coefficient values.

  18. Essential Experimental Methods for Identifying Bonghan Systems as a Basis for Korean Medicine: Focusing on Visual Materials from Original Papers and Modern Outcomes.

    PubMed

    Kim, Hoon-Gi; Lee, Byung-Cheon; Lee, Ki-Bog

    2015-01-01

    In the 1960s, through studies on Korean Medicine, Bonghan Kim proposed the Bonghan systems (BS) as the anatomical reality of the acupuncture meridians based on various experimental data. Since 2002, several groups, mainly led by a team at Seoul National University, who renamed the BS as the primo vascular system (PVS), have published around 70 papers showing biological structures corresponding to the BS. However, it is still difficult for other researchers to find them, especially under the skin, which Bonghan Kim first reported as acupuncture points, due to similar-looking biological tissues, for example, the lymphatic vessels, and such artifacts as blood clots or fascia debris. To solve these drawbacks, we examined the main methods for identifying the BS by comparing the original papers with the modern outcomes in terms of the common physical/chemical characteristics of the BS. In addition, effective methods of staining and microscopic observations discovered by modern teams are synthetically explained using visual materials such as diagrams and photos. Through the essentially organized methods in this review paper, we suggest that one can find the BS under the skin as putative acupuncture points by tracing the intraexternal BS, from which a new Korean Medicine will be born.

  19. Role of the metal cation types around VO4 groups on the nonlinear optical behavior of materials: experimental and theoretical analysis.

    PubMed

    Su, Xin; Yang, Zhihua; Han, Guopeng; Wang, Ying; Wen, Ming; Pan, Shilie

    2016-09-28

    In order to explore new NLO crystals with superior performances, it is greatly desirable to understand the intrinsic relationship between the macroscopic optical properties and microscopic structural features in crystals. A novel mechanism for nonlinear optical (NLO) effects of vanadate crystals, Li3VO4, KCd4(VO4)3 and Ca3(VO4)2 with distorted (VO4)(3-) groups, has been investigated. Experiments related to the synthesis and structures were determined. In addition, infrared and UV-Vis-NIR diffuse reflectance spectroscopy, as well as electronic band structure calculations, were performed on the reported materials. A comprehensive analysis for the structure-property relationship is given by combining the experimental measurements, the electronic structure calculations and the SHG-weighted electron density to the linear and NLO properties. It was found that the contribution of the (VO4)(3-) anionic group to the second harmonic generation (SHG) response was the dominant anionic group, which plays a vital role to the SHG effects in Li3VO4, KCd4(VO4)3 and Ca3(VO4)2. It was also concluded that the metal cation types and coordination around VO4 groups, the distorted and parallel oriented VO4 tetrahedron decided the SHG coefficient values. PMID:27549347

  20. Essential Experimental Methods for Identifying Bonghan Systems as a Basis for Korean Medicine: Focusing on Visual Materials from Original Papers and Modern Outcomes

    PubMed Central

    Kim, Hoon-Gi; Lee, Byung-Cheon; Lee, Ki-Bog

    2015-01-01

    In the 1960s, through studies on Korean Medicine, Bonghan Kim proposed the Bonghan systems (BS) as the anatomical reality of the acupuncture meridians based on various experimental data. Since 2002, several groups, mainly led by a team at Seoul National University, who renamed the BS as the primo vascular system (PVS), have published around 70 papers showing biological structures corresponding to the BS. However, it is still difficult for other researchers to find them, especially under the skin, which Bonghan Kim first reported as acupuncture points, due to similar-looking biological tissues, for example, the lymphatic vessels, and such artifacts as blood clots or fascia debris. To solve these drawbacks, we examined the main methods for identifying the BS by comparing the original papers with the modern outcomes in terms of the common physical/chemical characteristics of the BS. In addition, effective methods of staining and microscopic observations discovered by modern teams are synthetically explained using visual materials such as diagrams and photos. Through the essentially organized methods in this review paper, we suggest that one can find the BS under the skin as putative acupuncture points by tracing the intraexternal BS, from which a new Korean Medicine will be born. PMID:26539230

  1. Experimental Studies of Selected Aqueous Electrochemical Systems Relevant for Materials Processing in the Fabrications of Microelectronic Components and Direct Alcohol Fuel Cells

    NASA Astrophysics Data System (ADS)

    Shi, Xingzhao

    A broad range of electrochemical techniques are employed in this dissertation to investigate a selected set of aqueous electrochemical systems that are relevant for materials processing in the fabrication of microelectronic devices and direct alcohol fuel cells. In terms of technical applications, this work covers three main experimental systems: (i) chemical mechanical planarization (CMP), (ii) electro-less nickel deposition, and (iii) direct alkaline glycerol fuel cells. The first two areas are related to electronic device fabrications and the third topic is related to cost-effective energy conversion. The common electrochemical aspect of these different systems is that, in all these cases the active material characteristics are governed by complex (often multi-step) reactions occurring at metal-liquid (aqueous) interfaces. Electro-analytical techniques are ideally suited for studying the detailed mechanisms of such reactions, and the present investigation is largely focused on developing adequate analytical strategies for probing these reaction mechanisms. In the fabrication of integrated circuits, certain steps of materials processing involve CMP of Al deposited on thin layers of diffusion barrier materials like Ta/TaN, Co, or Ti/TiN. A specific example of this situation is found in the processing of replacement metal gates used for high-k/metal-gate transistors. Since the commonly used barrier materials are nobler than Al, the Al interface in contact with the barrier can become prone to galvanic corrosion in the wet CMP environment. Using model systems of coupon electrodes and two specific barrier metals, Ta and Co, the electrochemical factors responsible for these corrosion effects are investigated here in a moderately acidic (pH = 4.0) abrasive-free solution. The techniques of cyclic voltammetry and impedance spectroscopy are combined with strategic measurements of galvanic currents and open circuit potentials (OCPs). L-ascorbic acid (AA) is employed as a

  2. Safety of patients--actual problem of modern medicine (review).

    PubMed

    Tsintsadze, Neriman; Samnidze, L; Beridze, T; Tsintsadze, M; Tsintsadze, Nino

    2011-09-01

    Safety of patients is actual problem of up-to-date medicine. The current successful treatment of various sicknesses is achieved by implementation in clinical practice such medical preparations (medications), which are characterized with the high therapeutic activity, low toxicity and prolonged effects. In spite of evidence of the pharmacotherapeutical advances, the frequency of complications after medication has grown - that is why the safety of patients is the acute actual problem of medicine and ecological state of human population today. PMID:22156680

  3. An experimental charge density study of the effect of the noncentric crystal field on the molecular properties of organic NLO materials.

    PubMed

    Gopalan, R S; Kulkarni, G U; Rao, C N

    2000-11-01

    The structure, packing, and charge distribution in molecules of nonlinear optical materials have been analysed with reference to their counterparts in centrosymmetric structures based on low temperature X-ray measurements. The systems studied are the centric and noncentric polymorphs of 5-nitrouracil as well as the diamino, dithio, and thioamino derivatives of 1,1-ethylenedicarbonitrile; the latter possesses a noncentric structure. The molecular structure of 5-nitrouracil is invariant between the two forms, while the crystal packing is considerably different, leading to dimeric N-H·∙∙O rings in the centric polymorph and linear chains in noncentric one. There is an additional C-H·∙∙O contact in the centric form with a significant overlap of the electrostatic potentials between the alkenyl hydrogen atom and an oxygen atom of the nitro group. The dipole moment of 5-nitrouracil in the noncentric form is much higher (μ=9 D) than in the centric form (≈6 D). Among the 1,1-ethylenedicarbonitriles, there is an increased charge separation in the noncentric thioamino derivative, leading to an enhanced dipole of 15 D compared to the centric diamino (5 D) and dithio (6 D) derivatives. The effect of the crystal field is borne out by semiempirical AM1 calculations on the two systems. Dipole moments calculated for the molecules in the frozen geometries match closely with those obtained for centric crystals from the experimental charge densities. The calculated values of the dipole moment in the frozen or optimized geometries in the noncentric structures are, however, considerably lower than the observed value. Furthermore, the conformation of the S-CH(3) group in the noncentric crystal is anti with respect to the central C=C bond while the syn conformation is predicted for the free molecule in the optimized geometry. PMID:23696303

  4. [Formaldehyde determination in tobacco smoke--studies under experimental and actual conditions].

    PubMed

    Schaller, K H; Triebig, G; Beyer, B

    1989-11-01

    The estimation of an external exposure to formaldehyde in tobacco smoke requires a reliable analytical method. The gas chromatographic determination of formaldehyde shows in comparison to photometric methods a higher sensitivity and specificity. In the main stream smoke of various kinds of cigarettes the amount of formaldehyde vary between 3.4 micrograms to 8.8 micrograms/cigarette, this is equal to concentration between 2.3 to 6.1 ppm. In the air of lounges in hospitals formaldehyde concentrations up to 0.19 ppm can be detected after smoking of 15 cigarettes over a period of 1.5 h. In kindergartens without tobacco smoke the formaldehyde concentrations in air range from 0.005 to 0.01 ppm. The smoking of 30 cigarettes and one pipe in a non ventilated room over 1.5 h exceeded formaldehyde concentrations between 0.21 to 0.45 ppm. The concentration declines to 0.08 ppm within 2h after termination of smoking. The MAK-value of 0.5 ppm is not exceeded; in contrast to this the indoor limit of 0.1 ppm recommended by the German Bundesgesundheitsamt is exceeded in the vicinity of the smoker. The formaldehyde concentrations in tobacco smoke reported in the older literature can not be confirmed; this is due to the nonspecificity of the photometric methods. On the basis of our results can be concluded that the irritating effects of tobacco smoke to the mucous membranes are the result of the sum of irritating effects caused by several compounds and particles in the smoke and not only the impact of formaldehyde.

  5. Dynamic Characterization and Modeling of Potting Materials for Electronics Assemblies

    NASA Astrophysics Data System (ADS)

    Joshi, Vasant; Lee, Gilbert; Santiago, Jaime

    2015-06-01

    Prediction of survivability of encapsulated electronic components subject to impact relies on accurate modeling. Both static and dynamic characterization of encapsulation material is needed to generate a robust material model. Current focus is on potting materials to mitigate high rate loading on impact. In this effort, encapsulation scheme consists of layers of polymeric material Sylgard 184 and Triggerbond Epoxy-20-3001. Experiments conducted for characterization of materials include conventional tension and compression tests, Hopkinson bar, dynamic material analyzer (DMA) and a non-conventional accelerometer based resonance tests for obtaining high frequency data. For an ideal material, data can be fitted to Williams-Landel-Ferry (WLF) model. A new temperature-time shift (TTS) macro was written to compare idealized temperature shift factor (WLF model) with experimental incremental shift factors. Deviations can be observed by comparison of experimental data with the model fit to determine the actual material behavior. Similarly, another macro written for obtaining Ogden model parameter from Hopkinson Bar tests indicates deviations from experimental high strain rate data. In this paper, experimental results for different materials used for mitigating impact, and ways to combine data from resonance, DMA and Hopkinson bar together with modeling refinements will be presented.

  6. Experimental validation of a combined electromagnetic and thermal model for a microwave drying of capillary porous materials inside a rectangular wave guide (effects of irradiation time, particle sizes and initial moisture content).

    PubMed

    Ratanadecho, P; Aoki, K; Akahori, M

    2002-01-01

    In this paper, the experimental validation of a combined electromagnetic and thermal model for a microwave drying of capillary porous materials inside a rectangular wave guide is presented. The effects of the irradiation time, particle sizes and the variation of initial moisture content on the microwave drying kinetics are clarified in detail, considering the interference between incident and reflected waves in the capillary porous materials. The established model has allowed us to determine the space-time evolution of electric field, temperature and moisture content within capillary porous materials during microwave drying process.

  7. Relationship of perceived and actual motor competence in children.

    PubMed

    Raudsepp, Lennart; Liblik, Raino

    2002-06-01

    The purpose of this study was to examine the relationship between children's actual and perceived motor competence. 280 children between the ages of 10 and 13 years individually completed the Children's Physical Self-perception Profile which assesses perceptions of sport competence, physical conditioning, strength, body attractiveness, and general physical self-worth. The internal reliabilities (a) of the subscales ranged from .75 to .82. After completing the profile, the subject's actual motor competence was measured using tests of aerobic fitness and functional strength. Body fatness (sum of five skinfolds) was measured as an objective measure of perceived body attractiveness. Analysis of variance showed that boys and girls differed in perceived competence and actual motor competence. The boys showed higher perceived competence on four scores, but there was no sex difference in perception of body attractiveness. Correlations and regression analysis showed that actual and perceived motor competence were significantly but only moderately (r =.25-.56) correlated. In addition, items of perceived physical competence and age accounted for 17% (sit-ups) to 25% (endurance shuttle run) of the variance in actual motor competence of the children. These findings showed that 10- to 13-yr-old children can only moderately assess personal motor competence. PMID:12186225

  8. Experimental Studies of Selected Aqueous Electrochemical Systems Relevant for Materials Processing in the Fabrications of Microelectronic Components and Direct Alcohol Fuel Cells

    NASA Astrophysics Data System (ADS)

    Shi, Xingzhao

    A broad range of electrochemical techniques are employed in this dissertation to investigate a selected set of aqueous electrochemical systems that are relevant for materials processing in the fabrication of microelectronic devices and direct alcohol fuel cells. In terms of technical applications, this work covers three main experimental systems: (i) chemical mechanical planarization (CMP), (ii) electro-less nickel deposition, and (iii) direct alkaline glycerol fuel cells. The first two areas are related to electronic device fabrications and the third topic is related to cost-effective energy conversion. The common electrochemical aspect of these different systems is that, in all these cases the active material characteristics are governed by complex (often multi-step) reactions occurring at metal-liquid (aqueous) interfaces. Electro-analytical techniques are ideally suited for studying the detailed mechanisms of such reactions, and the present investigation is largely focused on developing adequate analytical strategies for probing these reaction mechanisms. In the fabrication of integrated circuits, certain steps of materials processing involve CMP of Al deposited on thin layers of diffusion barrier materials like Ta/TaN, Co, or Ti/TiN. A specific example of this situation is found in the processing of replacement metal gates used for high-k/metal-gate transistors. Since the commonly used barrier materials are nobler than Al, the Al interface in contact with the barrier can become prone to galvanic corrosion in the wet CMP environment. Using model systems of coupon electrodes and two specific barrier metals, Ta and Co, the electrochemical factors responsible for these corrosion effects are investigated here in a moderately acidic (pH = 4.0) abrasive-free solution. The techniques of cyclic voltammetry and impedance spectroscopy are combined with strategic measurements of galvanic currents and open circuit potentials (OCPs). L-ascorbic acid (AA) is employed as a

  9. Meditation and college students' self-actualization and rated stress.

    PubMed

    Janowiak, J J; Hackman, R

    1994-10-01

    This paper concerns the efficacy of meditation and relaxation in promoting self-actualization and changes in self-reported stress among 62 college students. Two groups were given mantra meditation and a yogic relaxation technique referred to as Shavasana. Pre- and posttest measures were taken on the Personal Orientation Inventory and the Behavioral Relaxation Scale. Both groups showed significant increases in scores on self-actualization; however, no differences were found between groups. Meditation training was associated with larger gains in scores on measures of systematic relaxed behavior than of the relaxation training.

  10. Experimental simulation of the water cooling of corium spread over the floor of a BWR containment

    SciTech Connect

    Morage, F.; Lahey, R.T. Jr.; Podowski, M.Z.

    1995-09-01

    This paper is concerned with an experimental investigation of the cooling effect of water collected on the surface of corium released onto the floor of a BWR drywell. In the present experiments, the actual reactor materials were replaced by simulant materials. Specifically, the results are shown for Freon-11 film boiling over liquid Wood`s metal spread above a solid porous surface through which argon gas was injected. An analysis of the obtained experimental data revealed that the actual film boiling heat transfer between a molten pool of corium and the water above the pool should be more efficient than predicted by using standard correlations for boiling over solid surfaces. This effect will be further augmented by the gas released due to the ablation of concrete floor beneath the corium and percolating towards its upper surface and into through the water layer above.

  11. MLCMS Actual Use, Perceived Use, and Experiences of Use

    ERIC Educational Resources Information Center

    Asiimwe, Edgar Napoleon; Grönlund, Åke

    2015-01-01

    Mobile learning involves use of mobile devices to participate in learning activities. Most e-learning activities are available to participants through learning systems such as learning content management systems (LCMS). Due to certain challenges, LCMS are not equally accessible on all mobile devices. This study investigates actual use, perceived…

  12. Actual Leisure Participation of Norwegian Adolescents with Down Syndrome

    ERIC Educational Resources Information Center

    Dolva, Anne-Stine; Kleiven, Jo; Kollstad, Marit

    2014-01-01

    This article reports the actual participation in leisure activities by a sample of Norwegian adolescents with Down syndrome aged 14. Representing a first generation to grow up in a relatively inclusive context, they live with their families, attend mainstream schools, and are part of common community life. Leisure information was obtained in…

  13. Actualizing Concepts in Home Management: Proceedings of a National Conference.

    ERIC Educational Resources Information Center

    American Home Economics Association, Washington, DC.

    The booklet prints the following papers delivered at a national conference: Actualizing Concepts in Home Management: Decision Making, Dorothy Z. Price; Innovations in Teaching: Ergonomics, Fern E. Hunt; Relevant Concepts of Home Management: Innovations in Teaching, Kay P. Edwards; Standards in a Managerial Context, Florence S. Walker; Organizing:…

  14. Reported vs. Actual Job Search by Unemployment Insurance Claimants.

    ERIC Educational Resources Information Center

    St. Louis, Robert D.; And Others

    1986-01-01

    Compares self-reported job search contacts of unemployment insurance recipients with independently verified job-search contacts. The separate equations estimated for reported and actual job contacts suggest that systematic misreporting may distort the conclusions. Some implications of the findings for reported unemployment rates also are explored.…

  15. Progressive Digressions: Home Schooling for Self-Actualization.

    ERIC Educational Resources Information Center

    Rivero, Lisa

    2002-01-01

    Maslow's (1971) theory of primary creativeness is used as the basis for a self-actualization model of education. Examples of how to use the model in creative homeschooling are provided. Key elements include digressive and immersion learning, self-directed learning, and the integration of work and play. Teaching suggestions are provided. (Contains…

  16. 40 CFR 74.22 - Actual SO2 emissions rate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ....6 for natural gas For other fuels, the combustion source must specify the SO2 emissions factor. (c... (2) For a combustion source submitting annual data: ER04AP95.005 where, “quantity of fuel consumed... (CONTINUED) SULFUR DIOXIDE OPT-INS Allowance Calculations for Combustion Sources § 74.22 Actual SO2...

  17. 40 CFR 74.22 - Actual SO2 emissions rate.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ....6 for natural gas For other fuels, the combustion source must specify the SO2 emissions factor. (c... (2) For a combustion source submitting annual data: ER04AP95.005 where, “quantity of fuel consumed... (CONTINUED) SULFUR DIOXIDE OPT-INS Allowance Calculations for Combustion Sources § 74.22 Actual SO2...

  18. The Implications of Language for Facilitating Self-Actualization.

    ERIC Educational Resources Information Center

    Davis, Charleen Katharine

    The purpose of this study was to delineate the implications of language within an educational context as a means of facilitating self-actualization. Three premises identified in a priori fashion were drawn from the literature in linguistics, psychology, and general semantics, creating a three-part language continuum--acquisition, development, and…

  19. Student Exposure to Actual Patients in the Classroom.

    ERIC Educational Resources Information Center

    Chisholm, Marie A.; McCall, Charles Y.; Francisco, George E., Jr.; Poirier, Sylvie

    1997-01-01

    Two clinical courses for first-year dental students were designed to develop students' interaction skills through actual patient case presentations and discussions and an interdisciplinary teaching approach. Results indicate students preferred the case presentations, with or without lecture, to the lecture-only approach and felt they learned more…

  20. Stability Tests with Actual Savannah River Site Radioactive Waste

    SciTech Connect

    Walker, D.D.

    2002-09-09

    solutions in two laboratory experiments. The first experiment tested four waste solutions for supersaturation of aluminum by monitoring the aluminum concentration after seeding with gibbsite. The second experiment tested two waste samples for precipitation of aluminosilicates by heating the solutions to accelerate solids formation. The results of the experiments with actual waste solutions are supported in this report.

  1. What Does the Force Concept Inventory Actually Measure?

    ERIC Educational Resources Information Center

    Huffman, Douglas; Heller, Patricia

    1995-01-01

    The Force Concept Inventory (FCI) is a 29-question, multiple-choice test designed to assess students' Newtonian and non-Newtonian conceptions of force. Presents an analysis of FCI results as one way to determine what the inventory actually measures. (LZ)

  2. 24 CFR 242.42 - Certificates of actual cost.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER AUTHORITIES MORTGAGE INSURANCE FOR HOSPITALS Endorsement for Insurance § 242.42 Certificates of actual cost. (a) The... cost, such certification shall be final and incontestable except for fraud or...

  3. 24 CFR 242.42 - Certificates of actual cost.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER AUTHORITIES MORTGAGE INSURANCE FOR HOSPITALS Endorsement for Insurance § 242.42 Certificates of actual cost. (a) The... cost, such certification shall be final and incontestable except for fraud or...

  4. Commitment to Change Statements Can Predict Actual Change in Practice

    ERIC Educational Resources Information Center

    Wakefield, Jacqueline; Herbert, Carol P.; Maclure, Malcolm; Dormuth, Colin; Wright, James M.; Legare, Jeanne; Brett-MacLean, Pamela; Premi, John

    2003-01-01

    Introduction: Statements of commitment to change are advocated both to promote and to assess continuing education interventions. However, most studies of commitment to change have used self-reported outcomes, and self-reports may significantly overestimate actual performance. As part of an educational randomized controlled trial, this study…

  5. A Taxometric Analysis of Actual Internet Sports Gambling Behavior

    ERIC Educational Resources Information Center

    Braverman, Julia; LaBrie, Richard A.; Shaffer, Howard J.

    2011-01-01

    This article presents findings from the first taxometric study of actual gambling behavior to determine whether we can represent the characteristics of extreme gambling as qualitatively distinct (i.e., taxonic) or as a point along a dimension. We analyzed the bets made during a 24-month study period by the 4,595 most involved gamblers among a…

  6. The Methodology of Calculation of Cutting Forces When Machining Composite Materials

    NASA Astrophysics Data System (ADS)

    Rychkov, D. A.; Yanyushkin, A. S.

    2016-08-01

    Cutting of composite materials has specific features and is different from the processing of metals. When this characteristic intense wear of the cutting tool. An important criterion in the selection process parameters composite processing is the value of the cutting forces, which depends on many factors and is determined experimentally, it is not always appropriate. The study developed a method of determining the cutting forces when machining composite materials and the comparative evaluation of the calculated and actual values of cutting forces. The methodology for calculating cutting forces into account specific features of the cutting tool and the extent of wear, the strength properties of the processed material and cutting conditions. Experimental studies conducted with fiberglass milling cutter equipped with elements of hard metal VK3M. The discrepancy between the estimated and the actual values of the cutting force is not more than 10%.

  7. Understanding and Predicting the Thermal Explosion Violence of HMX-Based and RDX-Based Explosives - Experimental Measurements of Material Properties and Reaction Violence

    SciTech Connect

    Maienschein, J L; Wardell, J F; Weese, R K; Cunningham, B J; Tran, T D

    2002-07-03

    The violence of thermal explosions with energetic materials is affected by many material properties, including mechanical and thermal properties, thermal ignition kinetics, and deflagration behavior. These properties must be characterized for heated samples as well as pristine materials. We present available data for these properties for two HMX-based formulations--LX-04 and PBX-9501, and two RDX-based formulations--Composition B and PBXN-109. We draw upon separately published data on the thermal explosion violence with these materials to compare the material properties with the observed violence. We have the most extensive data on deflagration behavior of these four formulations, and we discuss the correlation of the deflagration data with the violence results. The data reported here may also be used to develop models for application in simulation codes such as ALE3D to calculate and Dredict thermal explosion violence.

  8. 19 CFR 162.79b - Recovery of actual loss of duties, taxes and fees or actual loss of revenue.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... case in which a monetary penalty is not assessed or a written notification of claim of monetary penalty is not issued, the port director will issue a written notice to the person of the liability for the... actual loss of revenue. Whether or not a monetary penalty is assessed under this subpart, the...

  9. Multiple networks in soft materials: polycontinuity

    NASA Astrophysics Data System (ADS)

    Hyde, Stephen

    2015-03-01

    Bicontinuous network phases contain a pair of interwoven labyrinths. Analogous patterns with 3,4, .., 8, .., 54,... labyrinths are readily constructed via 2d hyperbolic geometry. Some of these have been realised in synthetic materials, from mesoporous silicates and lyotropic liquid crystals to metal-organic frameworks. We stumbled on polycontinuous forms while exploring 2d hyperbolic geometry. The only known tricontinuous phase found to date in mesoscale self-assembled materials was described via 2d non-euclidean geometry many years before its discovery. This example demonstrates the relevance of regular patterns in non-euclidean 2d spaces to self-assembled morphologies in actual materials. One route to explicit ground-up design of mesoscale polycontinuous phases is via star-shaped molecules with immiscible arms, such as Y-shaped ``polyphiles.'' Some results of theoretical geometric modelling, simulation and experimental formulation of lyotropic LC mesophases with polyphiles will be discussed.

  10. Practices and Methods for Actualization of the Scientific Information in Art Excursions (Excursions and Cultural Heritage in the Contemporary World)

    ERIC Educational Resources Information Center

    Portnova, Tatiana V.

    2016-01-01

    The paper deals with various practices and methods for actualization of the scientific information in art excursions. The modern society is characterized by commitment to information richness. The range of cultural and historical materials used as the basis for art excursions is really immense. However if to consider the number of excursions with…

  11. Effect of an Experimental Direct Pulp-capping Material on the Properties and Osteogenic Differentiation of Human Dental Pulp Stem Cells

    PubMed Central

    Yu, Fan; Dong, Yan; Yang, Yan-wei; Lin, Ping-ting; Yu, Hao-han; Sun, Xiang; Sun, Xue-fei; Zhou, Huan; Huang, Li; Chen, Ji-hua

    2016-01-01

    Effective pulp-capping materials must have antibacterial properties and induce dentin bridge formation; however, many current materials do not satisfy clinical requirements. Accordingly, the effects of an experiment pulp-capping material (Exp) composed of an antibacterial resin monomer (MAE-DB) and Portland cement (PC) on the viability, adhesion, migration, and differentiation of human dental pulp stem cells (hDPSCs) were examined. Based on a Cell Counting Kit-8 assay, hDPSCs exposed to Exp extracts showed limited viability at 24 and 48 h, but displayed comparable viability to the control at 72 h. hDPSC treatment with Exp extracts enhanced cellular adhesion and migration according to in vitro scratch wound healing and Transwell migration assays. Exp significantly upregulated the expression of osteogenesis-related genes. The hDPSCs cultured with Exp exhibited higher ALP activity and calcium deposition in vitro compared with the control group. The novel material showed comparable cytocompatibility to control cells and promoted the adhesion, migration, and osteogenic differentiation of hDPSCs, indicating excellent biocompatibility. This new direct pulp-capping material containing MAE-DB and PC shows promise as a potential alternative to conventional materials for direct pulp capping. PMID:27698421

  12. Effect of an Experimental Direct Pulp-capping Material on the Properties and Osteogenic Differentiation of Human Dental Pulp Stem Cells

    NASA Astrophysics Data System (ADS)

    Yu, Fan; Dong, Yan; Yang, Yan-Wei; Lin, Ping-Ting; Yu, Hao-Han; Sun, Xiang; Sun, Xue-Fei; Zhou, Huan; Huang, Li; Chen, Ji-Hua

    2016-10-01

    Effective pulp-capping materials must have antibacterial properties and induce dentin bridge formation; however, many current materials do not satisfy clinical requirements. Accordingly, the effects of an experiment pulp-capping material (Exp) composed of an antibacterial resin monomer (MAE-DB) and Portland cement (PC) on the viability, adhesion, migration, and differentiation of human dental pulp stem cells (hDPSCs) were examined. Based on a Cell Counting Kit-8 assay, hDPSCs exposed to Exp extracts showed limited viability at 24 and 48 h, but displayed comparable viability to the control at 72 h. hDPSC treatment with Exp extracts enhanced cellular adhesion and migration according to in vitro scratch wound healing and Transwell migration assays. Exp significantly upregulated the expression of osteogenesis-related genes. The hDPSCs cultured with Exp exhibited higher ALP activity and calcium deposition in vitro compared with the control group. The novel material showed comparable cytocompatibility to control cells and promoted the adhesion, migration, and osteogenic differentiation of hDPSCs, indicating excellent biocompatibility. This new direct pulp-capping material containing MAE-DB and PC shows promise as a potential alternative to conventional materials for direct pulp capping.

  13. Actual curriculum development practices instrument: Testing for factorial validity

    NASA Astrophysics Data System (ADS)

    Foi, Liew Yon; Bakar, Kamariah Abu; Hamzah, Mohd Sahandri Gani; Alwi, Nor Hayati

    2014-09-01

    The Actual Curriculum Development Practices Instrument (ACDP-I) was developed and the factorial validity of the ACDP-I was tested (n = 107) using exploratory factor analysis procedures in the earlier work of [1]. Despite the ACDP-I appears to be content and construct valid instrument with very high internal reliability qualities for using in Malaysia, the accumulated evidences are still needed to provide a sound scientific basis for the proposed score interpretations. Therefore, the present study addresses this concern by utilising the confirmatory factor analysis to further confirm the theoretical structure of the variable Actual Curriculum Development Practices (ACDP) and enrich the psychometrical properties of ACDP-I. Results of this study have practical implication to both researchers and educators whose concerns focus on teachers' classroom practices and the instrument development and validation process.

  14. 63. VIEW OF AUTOTRANSFERS. THE ACTUAL AUTOTRANSFERS ARE ENCLOSED IN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    63. VIEW OF AUTOTRANSFERS. THE ACTUAL AUTOTRANSFERS ARE ENCLOSED IN THE OIL FILLED CYLINDERS ON THE RIGHT OF THE PHOTOGRAPH. THESE ELECTRICAL DEVICES BOOSTED THE GENERATOR OUTPUT OF 11,000 VOLTS TO 22,000 VOLTS PRIOR TO TRANSMISSION OUT TO THE MAIN FEEDER LINES. A SPARE INNER UNIT IS CONTAINED IN THE METAL BOX AT THE LEFT OF THE PHOTOGRAPH. - New York, New Haven & Hartford Railroad, Cos Cob Power Plant, Sound Shore Drive, Greenwich, Fairfield County, CT

  15. FRACTIONAL CRYSTALLIZATION FLOWSHEET TESTS WITH ACTUAL TANK WASTE

    SciTech Connect

    HERTING, D.L.

    2006-10-18

    Laboratory-scale flowsheet tests of the fractional crystallization process were conducted with actual tank waste samples in a hot cell at the 222-S Laboratory. The process is designed to separate medium-curie liquid waste into a low-curie stream for feeding to supplemental treatment and a high-curie stream for double-shell tank storage. Separations criteria (for Cs-137 sulfate, and sodium) were exceeded in all three of the flowsheet tests that were performed.

  16. FRACTIONAL CRYSTALLIZATION FLOWSHEET TESTS WITH ACTUAL TANK WASTE

    SciTech Connect

    HERTING, D.L.

    2007-04-13

    Laboratory-scale flowsheet tests of the fractional crystallization process were conducted with actual tank waste samples in a hot cell at the 2224 Laboratory. The process is designed to separate medium-curie liquid waste into a low-curie stream for feeding to supplemental treatment and a high-curie stream for double-shell tank storage. Separations criteria (for Cesium-137 sulfate and sodium) were exceeded in all three of the flowsheet tests that were performed.

  17. Perceived accessibility versus actual physical accessibility of healthcare facilities.

    PubMed

    Sanchez, J; Byfield, G; Brown, T T; LaFavor, K; Murphy, D; Laud, P

    2000-01-01

    This study addressed how healthcare clinics perceive themselves in regard to accessibility for persons with spinal cord injuries (SCI). All 40 of the clinics surveyed reported that they were wheelchair accessible; however, there was significant variability in the number of sites that actually met the guidelines of the Americans with Disability Act. In general, a person using a wheelchair could enter the building, the examination room, and the bathroom. The majority of sites did not have an examination table that could be lowered to wheelchair level. Most reported limited experience in working with persons with (SCI), yet they claimed to be able to assist with difficult transfers. Only one site knew about autonomic dysreflexia. Problems of accessibility appeared to be seriously compounded by the clinics' perception of how they met physical accessibility guidelines without consideration of the actual needs of persons with SCI. This study addressed the perception of accessibility as reported by clinic managers versus actual accessibility in healthcare clinics in a Midwestern metropolitan area for persons using wheelchairs. PMID:10754921

  18. The actual citation impact of European oncological research.

    PubMed

    López-Illescas, Carmen; de Moya-Anegón, Félix; Moed, Henk F

    2008-01-01

    This study provides an overview of the research performance of major European countries in the field Oncology, the most important journals in which they published their research articles, and the most important academic institutions publishing them. The analysis was based on Thomson Scientific's Web of Science (WoS) and calculated bibliometric indicators of publication activity and actual citation impact. Studying the time period 2000-2006, it gives an update of earlier studies, but at the same time it expands their methodologies, using a broader definition of the field, calculating indicators of actual citation impact, and analysing new and policy relevant aspects. Findings suggest that the emergence of Asian countries in the field Oncology has displaced European articles more strongly than articles from the USA; that oncologists who have published their articles in important, more general journals or in journals covering other specialties, rather than in their own specialist journals, have generated a relatively high actual citation impact; and that universities from Germany, and--to a lesser extent--those from Italy, the Netherlands, UK, and Sweden, dominate a ranking of European universities based on number of articles in oncology. The outcomes illustrate that different bibliometric methodologies may lead to different outcomes, and that outcomes should be interpreted with care.

  19. Laboratory Demonstration of the Pretreatment Process with Caustic and Oxidative Leaching Using Actual Hanford Tank Waste

    SciTech Connect

    Fiskum, Sandra K.; Billing, Justin M.; Buck, Edgar C.; Daniel, Richard C.; Draper, Kathryn E.; Edwards, Matthew K.; Jenson, Evan D.; Kozelisky, Anne E.; MacFarlan, Paul J.; Peterson, Reid A.; Shimskey, Rick W.; Snow, Lanee A.

    2009-01-01

    This report describes the bench-scale pretreatment processing of actual tank waste materials through the entire baseline WTP pretreatment flowsheet in an effort to demonstrate the efficacy of the defined leaching processes on actual Hanford tank waste sludge and the potential impacts on downstream pretreatment processing. The test material was a combination of reduction oxidation (REDOX) tank waste composited materials containing aluminum primarily in the form of boehmite and dissolved S saltcake containing Cr(III)-rich entrained solids. The pretreatment processing steps tested included • caustic leaching for Al removal • solids crossflow filtration through the cell unit filter (CUF) • stepwise solids washing using decreasing concentrations of sodium hydroxide with filtration through the CUF • oxidative leaching using sodium permanganate for removing Cr • solids filtration with the CUF • follow-on solids washing and filtration through the CUF • ion exchange processing for Cs removal • evaporation processing of waste stream recycle for volume reduction • combination of the evaporated product with dissolved saltcake. The effectiveness of each process step was evaluated by following the mass balance of key components (such as Al, B, Cd, Cr, Pu, Ni, Mn, and Fe), demonstrating component (Al, Cr, Cs) removal, demonstrating filterability by evaluating filter flux rates under various processing conditions (transmembrane pressure, crossflow velocities, wt% undissolved solids, and PSD) and filter fouling, and identifying potential issues for WTP. The filterability was reported separately (Shimskey et al. 2008) and is not repeated herein.

  20. Experimental determination of satellite bolted joints thermal resistance

    NASA Technical Reports Server (NTRS)

    Mantelli, Marcia Barbosa Henriques; Basto, Jose Edson

    1990-01-01

    The thermal resistance was experimentally determined of the bolted joints of the first Brazilian satellite (SCD 01). These joints, used to connect the satellite structural panels, are reproduced in an experimental apparatus, keeping, as much as possible, the actual dimensions and materials. A controlled amount of heat is forced to pass through the joint and the difference of temperature between the panels is measured. The tests are conducted in a vacuum chamber with liquid nitrogen cooled walls, that simulates the space environment. Experimental procedures are used to avoid much heat losses, which are carefully calculated. Important observations about the behavior of the joint thermal resistance with the variation of the mean temperature are made.

  1. Experimental analysis of the material degradation of PET on a co-rotating twin-screw extruder for varying vacuum pressures

    NASA Astrophysics Data System (ADS)

    Herken, T.; Fecke, N.; Schöppner, V.

    2015-05-01

    Plastics, starting from inexpensive mass-produced articles to technical high-end applications, are being used in ever more areas of life. The main drivers are their flexible product properties and the resultant broad application possibilities. To be able to offer plastic products inexpensively and conserve the environment at the same time, more and more attention is being paid to plastics recycling. Polyethylene terephthalate - in short PET - is of particular significance here because of its frequent application in the film and packaging industry and its special material properties. The recycling of PET, however, can only be carried out a limited number of times because it's processing necessarily results in both thermal and mechanical stresses on the material. This is the basis for the reactions at molecular level, which result in a shortening of the molecule chains (material degradation) and exert a negative effect on the product properties. The aim of this study is to identify the factors that influence the material degradation of PET in twin-screw extrusion. To do this, various screw configurations and different speed and throughput conditions are examined in a series of experiments. Furthermore, material specimens are removed along the length of the screw in order to evaluate the influence of individual screw sections. By determining the intrinsic viscosity of the specimens, it is possible to measure the mean molecular weight and thus the material damage. Based on the test results, guidelines are drawn up for the compounding of PET so as to ensure as little damage as possible to the material.

  2. Experimental analysis of the material degradation of PET on a co-rotating twin-screw extruder for varying vacuum pressures

    SciTech Connect

    Herken, T.; Fecke, N.; Schöppner, V. E-mail: Nikolas.Fecke@ktp.uni-paderborn.de

    2015-05-22

    Plastics, starting from inexpensive mass-produced articles to technical high-end applications, are being used in ever more areas of life. The main drivers are their flexible product properties and the resultant broad application possibilities. To be able to offer plastic products inexpensively and conserve the environment at the same time, more and more attention is being paid to plastics recycling. Polyethylene terephthalate – in short PET – is of particular significance here because of its frequent application in the film and packaging industry and its special material properties. The recycling of PET, however, can only be carried out a limited number of times because it’s processing necessarily results in both thermal and mechanical stresses on the material. This is the basis for the reactions at molecular level, which result in a shortening of the molecule chains (material degradation) and exert a negative effect on the product properties. The aim of this study is to identify the factors that influence the material degradation of PET in twin-screw extrusion. To do this, various screw configurations and different speed and throughput conditions are examined in a series of experiments. Furthermore, material specimens are removed along the length of the screw in order to evaluate the influence of individual screw sections. By determining the intrinsic viscosity of the specimens, it is possible to measure the mean molecular weight and thus the material damage. Based on the test results, guidelines are drawn up for the compounding of PET so as to ensure as little damage as possible to the material.

  3. Working memory and acquisition of implicit knowledge by imagery training, without actual task performance.

    PubMed

    Helene, A F; Xavier, G F

    2006-04-28

    This study investigated acquisition of a mirror-reading skill via imagery training, without the actual performance of a mirror-reading task. In experiment I, healthy volunteers simulated writing on an imaginary, transparent screen placed at eye level, which could be read by an experimenter facing the subject. Performance of this irrelevant motor task required the subject to imagine the letters inverted, as if seen in a mirror from their own point of view (imagery training). A second group performed the same imagery training interspersed with a complex, secondary spelling and counting task. A third, control, group simply wrote the words as they would normally appear from their own point of view. After training with 300 words, all subjects were tested in a mirror-reading task using 60 non-words, constructed according to acceptable letter combinations of the Portuguese language. Compared with control subjects, those exposed to imagery training, including those who switched between imagery and the complex task, exhibited shorter reading times in the mirror-reading task. Experiment II employed a 2 x 3 design, including two training conditions (imagery and actual mirror-reading) and three competing task conditions (a spelling and counting switching task, a visual working memory concurrent task, and no concurrent task). Training sessions were interspersed with mirror-reading testing sessions for non-words, allowing evaluation of the mirror-reading acquisition process during training. The subjects exposed to imagery training acquired the mirror-reading skill as quickly as those exposed to the actual mirror-reading task. Further, performance of concurrent tasks together with actual mirror-reading training severely disrupted mirror-reading skill acquisition; this interference effect was not seen in subjects exposed to imagery training and performance of the switching and the concurrent tasks. These results unequivocally show that acquisition of implicit skills by top

  4. Determination of the thermophysical characteristics of certain structural materials under the conditions of thermal action from a high-temperature gas jet

    NASA Astrophysics Data System (ADS)

    Golovanov, A. N.; Kuzin, A. Ya.; Mikov, V. L.; Sazonov, V. V.

    2011-09-01

    Thermophysical characteristics of phenolic carbon-filled plastic P-5-13P and graphite V-1 have been investigated on an experimental setup simulating an actual solid-propellant rocket engine. Temperature and heat-flux density on the thermally stressed boundaries of samples of the materials under study have been determined by solution, with a regularizing algorithm, of the boundary inverse problem.

  5. Physico-chemical investigation of clayey/cement-based materials interaction in the context of geological waste disposal: Experimental approach and results

    SciTech Connect

    Dauzeres, A.; Le Bescop, P.; Sardini, P.; Cau Dit Coumes, C.

    2010-08-15

    Within the concepts under study for the geological disposal of intermediate-level long-lived waste, cement-based materials are considered as candidate materials. The clayey surrounding rock and the cement-based material being considered differ greatly in their porewater composition. Experiments are conducted on the diffusion of solutes constituting those porewaters in a confined clay/cement composite system using cells. The test temperature was set at 25 {sup o}C and 2, 6 and 12 months. Results supply new information: carbonation is low and not clog the interface. Such absence of carbonation allows for the diffusion of aqueous species and, thus, for the degradation of the cement paste and the illitisation of illite/smectite interstratifications. The cement material is subjected to a decalcification: portlandite dissolution and a CaO/SiO{sub 2} reduction in the calcium silicate hydrate. The sulphate in diffusion induces non-destructive ettringite precipitation in the largest pores. After 12 months, about 800 {mu}m of cement material is concerned by decalcification.

  6. An Experimental Copyright Moratorium: Study of a Proposed Solution to the Copyright Photocopying Problem. Final Report to the American Society for Testing and Materials (ASTM).

    ERIC Educational Resources Information Center

    Heilprin, Laurence B.

    The Committee to Investigate Copyright Problems (CICP), a non-profit organization dedicated to resolving the conflict known as the "copyright photocopying problem" was joined by the American Society for Testing and Materials (ASTM), a large national publisher of technical and scientific standards, in a plan to simulate a long-proposed solution to…

  7. Final Report. LAW Glass Formulation to Support AP-101 Actual Waste Testing, VSL-03R3470-2, Rev. 0

    SciTech Connect

    Muller, I. S.; Pegg, I. L.; Rielley, Elizabeth; Carranza, Isidro; Hight, Kenneth; Lai, Shan-Tao T.; Mooers, Cavin; Bazemore, Gina; Cecil, Richard; Kruger, Albert A.

    2015-06-22

    The main objective of the work was to develop and select a glass formulation for vitrification testing of the actual waste sample of LAW AP-101 at Battelle - Pacific Northwest Division (PNWD). Other objectives of the work included preparation and characterization of glasses to demonstrate compliance with contract and processing requirements, evaluation of the ability to achieve waste loading requirements, testing to demonstrate compatibility of the glass melts with melter materials of construction, comparison of the properties of simulant and actual waste glasses, and identification of glass formulation issues with respect to contract specifications and processing requirements.

  8. Time interval moderates the relationship between psyching-up and actual sprint performance.

    PubMed

    Hammoudi-Nassib, Sarra; Chtara, Moktar; Nassib, Sabri; Briki, Walid; Hammoudi-Riahi, Sabra; Tod, David; Chamari, Karim

    2014-11-01

    This study attempted to test whether the strongest effect of psyching-up (PU) strategy on actual sprint performance can be observed when the strategy is used immediately (or almost) before performance compared with when there is a delay between PU and performance. To do so, 16 male sprinters (age, 20.6 ± 1.3 years; body mass, 77.5 ± 7.1 kg; height, 180.8 ± 5.6 cm) were enrolled in a counterbalanced experimental design in which participants were randomly assigned to 10 sessions (2 [Experimental Condition: imagery vs. distraction] × 5 [Time Intervals: no interval, 1 minute, 2 minutes, 3 minutes, and 5 minutes]). Before performing the experimental tasks, participants rated: (a) the Hooper index, (b) their degree of self-confidence, and (c) after the completion of the experimental test; they rated their perceived effort. Findings showed that the imagery significantly improved sprint performance. Specifically, the imagery enhanced performance on the phase of acceleration (0-10 m) and on the overall sprint (0-30 m) when used immediately before performance and at 1- and 2-minute intervals but not for 3- and 5-minute intervals. These findings support the hypothesis that the potential effect of the PU strategy on performance vanishes over time. The pre-experimental task Hooper and self-efficacy indexes did not change across the 10 experimental sessions, reinforcing the view that the observed performance changes were directly caused by the experimental manipulation and not through any altered status of the athletes (self-efficacy, fatigue/recovery, and stress). The potential mechanisms underlying such a process and practical applications are discussed.

  9. Power Delivery from an Actual Thermoelectric Generation System

    NASA Astrophysics Data System (ADS)

    Kaibe, Hiromasa; Kajihara, Takeshi; Nagano, Kouji; Makino, Kazuya; Hachiuma, Hirokuni; Natsuume, Daisuke

    2014-06-01

    Similar to photovoltaic (PV) and fuel cells, thermoelectric generators (TEGs) supply direct-current (DC) power, essentially requiring DC/alternating current (AC) conversion for delivery as electricity into the grid network. Use of PVs is already well established through power conditioning systems (PCSs) that enable DC/AC conversion with maximum-power-point tracking, which enables commercial use by customers. From the economic, legal, and regulatory perspectives, a commercial PCS for PVs should also be available for TEGs, preferably as is or with just simple adjustment. Herein, we report use of a PV PCS with an actual TEG. The results are analyzed, and proper application for TEGs is proposed.

  10. Dieting: really harmful, merely ineffective or actually helpful?

    PubMed

    Lowe, Michael R; Timko, C Alix

    2004-08-01

    Dieting has developed a negative reputation among many researchers and health care professionals. However, 'dieting' can refer to a variety of behavioural patterns that are associated with different effects on eating and body weight. The wisdom of dieting depends on what kind of dieting is involved, who is doing it, and why. Thus, depending on what one means by the term, dieting can be quite harmful, merely ineffective or actually beneficial. The present paper considers examples of all three. In particular, we argue that judgements about the desirability of dieting should consider the likely consequences to particular individuals of engaging in, or not engaging in, dieting behaviour. PMID:15384317

  11. TESTING OF THE SPINTEK ROTARY MICROFILTER USING ACTUAL HANFORD WASTE SAMPLES

    SciTech Connect

    HUBER HJ

    2010-04-13

    The SpinTek rotary microfilter was tested on actual Hanford tank waste. The samples were a composite of archived Tank 241-AN-105 material and a sample representing single-shell tanks (SST). Simulants of the two samples have been used in non-rad test runs at the 222-S laboratory and at Savannah River National Laboratory (SRNL). The results of these studies are compared in this report. Two different nominal pore sizes for the sintered steel rotating disk filter were chosen: 0.5 and 0.1 {micro}m. The results suggest that the 0.5-{micro}m disk is preferable for Hanford tank waste for the following reasons: (1) The filtrate clarity is within the same range (<<4 ntu for both disks); (2) The filtrate flux is in general higher for the 0.5-{micro}m disk; and (3) The 0.1-{micro}m disk showed a higher likelihood of fouling. The filtrate flux of the actual tank samples is generally in the range of 20-30% compared to the equivalent non-rad tests. The AN-105 slurries performed at about twice the filtrate flux of the SST slurries. The reason for this difference has not been identified. Particle size distributions in both cases are very similar; comparison of the chemical composition is not conclusive. The sole hint towards what material was stuck in the filter pore holes came from the analysis of the dried flakes from the surface of the fouled 0.1-{micro}m disk. A cleaning approach developed by SRNL personnel to deal with fouled disks has been found adaptable when using actual Hanford samples. The use of 1 M nitric acid improved the filtrate flux by approximately two times; using the same simulants as in the non-rad test runs showed that the filtrate flux was restored to 1/2 of its original amount.

  12. [Healing of experimental defect in a long bone after implantation of "CollapAn" osteoplastic material in its cavity (computed tomographic study)].

    PubMed

    Kopen'kov, A V

    2015-01-01

    The dynamics of biodegradation of "CollapAn" osteoplastic material was studied after its implantation into the defect of the femoral diaphysis in 30 rats. Computed tomographic analysis of the healing of bone defects was conducted with the determination of the optical density of bone tissue in Hounsfield units. Since Day 30 of the experiment, the appearance and further progress of the radiographic signs of bone tissue neoformation and maturation were noted exactly along the contours of osteoplastic material, together with the gradual disappearance of the defect from the side of bone cortical layer and simultaneous increase of the optical density of the intermediary and endosteal part of the regenerate. At Day 120, regenerate optical density exceeded the absolute optical density of the parent bone; simultaneously, during this period no full recovery of the original shape of the bone took place, while parent bone rarefication was identified during all the periods of observation.

  13. Experimental study and neural network modeling of sugarcane bagasse pretreatment with H2SO4 and O3 for cellulosic material conversion to sugar.

    PubMed

    Gitifar, Vahid; Eslamloueyan, Reza; Sarshar, Mohammad

    2013-11-01

    In this study, pretreatment of sugarcane bagasse and subsequent enzymatic hydrolysis is investigated using two categories of pretreatment methods: dilute acid (DA) pretreatment and combined DA-ozonolysis (DAO) method. Both methods are accomplished at different solid ratios, sulfuric acid concentrations, autoclave residence times, bagasse moisture content, and ozonolysis time. The results show that the DAO pretreatment can significantly increase the production of glucose compared to DA method. Applying k-fold cross validation method, two optimal artificial neural networks (ANNs) are trained for estimations of glucose concentrations for DA and DAO pretreatment methods. Comparing the modeling results with experimental data indicates that the proposed ANNs have good estimation abilities. PMID:24035818

  14. Experimental study and neural network modeling of sugarcane bagasse pretreatment with H2SO4 and O3 for cellulosic material conversion to sugar.

    PubMed

    Gitifar, Vahid; Eslamloueyan, Reza; Sarshar, Mohammad

    2013-11-01

    In this study, pretreatment of sugarcane bagasse and subsequent enzymatic hydrolysis is investigated using two categories of pretreatment methods: dilute acid (DA) pretreatment and combined DA-ozonolysis (DAO) method. Both methods are accomplished at different solid ratios, sulfuric acid concentrations, autoclave residence times, bagasse moisture content, and ozonolysis time. The results show that the DAO pretreatment can significantly increase the production of glucose compared to DA method. Applying k-fold cross validation method, two optimal artificial neural networks (ANNs) are trained for estimations of glucose concentrations for DA and DAO pretreatment methods. Comparing the modeling results with experimental data indicates that the proposed ANNs have good estimation abilities.

  15. What do tests of formal reasoning actually measure?

    NASA Astrophysics Data System (ADS)

    Lawson, Anton E.

    Tests of formal operational reasoning derived from Piagetian theory have been found to be effective predictors of academic achievement. Yet Piaget's theory regarding the underlying nature of formal operations and their employment in specific contexts has run into considerable empirical difficulty. The primary purpose of this study was to present the core of an alternative theory of the nature of advanced scientific reasoning. That theory, referred to as the multiple-hypothesis theory, argues that tests of formal operational reasoning actually measure the extent to which persons have acquired the ability to initiate reasoning with more than one specific antecedent condition, or if they are unable to imagine more than one antecedent condition, they are aware that more than one is possible; therefore conclusions that are drawn are tempered by this possibility. As a test of this multiple-hypothesis theory of advanced reasoning and the contrasting Piagetian theory of formal operations, a sample of 922 college students were first classified as concrete operational, transitional, or formal operational, based upon responses to standard Piagetian measures of formal operational reasoning. They were then administered seven logic tasks. Actual response patterns to the tasks were analyzed and found to be similar to predicted response patterns derived from the multiple-hypothesis theory and were different from those predicted by Piagetian theory. Therefore, support was obtained for the multiple-hypothesis theory. The terms intuitive and reflective were suggested to replace the terms concrete operational and formal operational to refer to persons at varying levels of intellectual development.

  16. [The ethics of animal experimentation].

    PubMed

    Goffi, Jean-Yves

    2013-01-01

    The paper starts with a short definition of animal experimentation, then three main approaches to the practice are considered: unconditional approval (as advocated by Claude Bernard), conditional and restricted approval (as advocated by Peter Singer) and strict prohibition (as advocated by Tom Regan and Gary Francione). It is argued that what is actually approved or condemned in animal experimentation is the value of the scientific enterprise.

  17. Evidence for a new force in dissipative system derived from Boltzmann equation: Consequence for the mechanics of the material point, experimental evidences and possible applications

    NASA Astrophysics Data System (ADS)

    Evesque, Pierre

    2013-06-01

    A 1d Boltzmann equation is introduced to describe the speed distribution function in granular gas system with local collision dissipation. It leads to introduce a new term, equivalent to an acceleration This term was always assumed to be 0, but it is not zero in general, even when the system is steady (i.e. when local mean flow equals 0). This shows that the flow (+ boundary) exerts a force on any extra steady particle (or plane) that drives it to the center. This result is analyzed, compared and interpreted using the Lagrangian & Eulerian view points of the mechanics; it demonstrates that classic view point of hydrodynamics does not hold anymore. The paper investigates different cases and gives experimental evidences of the features: it explains while local speed distribution f(v,r) of granular gas in a box subjected to vibration is non symmetric in the direction of vibration, while the system is stationary (mean local speed equals 0). Papers giving local experimental or simulated distributions are quoted, where two local pressures P± = Σv>0,orv<0 (mv2) in +Ox and -Ox direction are different. It implies also introducing two local temperatures T± in the ±Ox vibration direction. These points are confirmed using 2d and 3d granular gas simulation. It should apply likely to get deeper understanding of different effects as the "granular Leidenfrost effect", the stoppage of vibrated-hourglass, some turbulent flow, and the granular-Maxwell-demon.

  18. Microstructure and Property Evolution in Advanced Cladding and Duct Materials Under Long-Term and Elevated Temperature Irradiation: Modeling and Experimental Investigation

    SciTech Connect

    Wirth, Brian; Morgan, Dane; Kaoumi, Djamel; Motta, Arthur

    2013-12-01

    The in-service degradation of reactor core materials is related to underlying changes in the irradiated microstructure. During reactor operation, structural components and cladding experience displacement of atoms by collisions with neutrons at temperatures at which the radiation-induced defects are mobile, leading to microstructure evolution under irradiation that can degrade material properties. At the doses and temperatures relevant to fast reactor operation, the microstructure evolves by dislocation loop formation and growth, microchemistry changes due to radiation-induced segregation, radiation-induced precipitation, destabilization of the existing precipitate structure, and in some cases, void formation and growth. These processes do not occur independently; rather, their evolution is highly interlinked. Radiationinduced segregation of Cr and existing chromium carbide coverage in irradiated alloy T91 track each other closely. The radiation-induced precipitation of Ni-Si precipitates and RIS of Ni and Si in alloys T91 and HCM12A are likely related. Neither the evolution of these processes nor their coupling is understood under the conditions required for materials performance in fast reactors (temperature range 300-600°C and doses beyond 200 dpa). Further, predictive modeling is not yet possible as models for microstructure evolution must be developed along with experiments to characterize these key processes and provide tools for extrapolation. To extend the range of operation of nuclear fuel cladding and structural materials in advanced nuclear energy and transmutation systems to that required for the fast reactor, the irradiation-induced evolution of the microstructure, microchemistry, and the associated mechanical properties at relevant temperatures and doses must be understood. Predictive modeling relies on an understanding of the physical processes and also on the development of microstructure and microchemical models to describe their evolution under

  19. HiPIMS "goes production", actual status & outlook

    NASA Astrophysics Data System (ADS)

    Lemmer, Oliver; Kölker, Werner; Bolz, Stephan; Schiffers, Christoph

    2012-09-01

    Hardness, toughness, and adhesion are today among the most important characteristics of PVD (Physical Vapor Deposition) coatings for machining tools that are used for highly demanding hard, high-speed, and dry machining. The continued development and improvement of materials constantly creates new and more demanding challenges for machining tools. In particular, materials that are especially hard or difficult to machine, materials that are prone to stress hardening, and materials with low heat conductivity require coatings with high thermal and oxidation stability in addition to the properties already mentioned. With a view to these properties, the new HiPIMS technology is currently being used to develop a new generation of coatings with significantly improved properties compared to conventional coatings. They are able to process hard-to-machine materials such as nickel-based alloys and stainless austenitic steels at lower costs - with comparatively significantly improved machining parameters and considerably less tool wear.

  20. An Experimental Investigation of Transverse Tension Fatigue Characterization of IM6/3501-6 Composite Materials Using a Three-Point Bend Test

    NASA Technical Reports Server (NTRS)

    Peck, Ann W.

    1998-01-01

    As composites are introduced into more complex structures with out-of-plane loadings, a better understanding is needed of the out-of-plane, matrix-dominated failure mechanisms. This work investigates the transverse tension fatigue characteristics of IM6/3501 composite materials. To test the 90 degree laminae, a three-point bend test was chosen, potentially minimizing handling and gripping issues associated with tension tests. A finite element analysis was performed of a particular specimen configuration to investigate the influence of specimen size on the stress distribution for a three-point bend test. Static testing of 50 specimens of 9 different sized configurations produced a mean transverse tensile strength of 61.3 Mpa (8.0 ksi). The smallest configuration (10.2 mm wide, Span-to-thickness ratio of 3) consistently exhibited transverse tensile failures. A volume scale effect was difficult to discern due to the large scatter of the data. Static testing of 10 different specimens taken from a second panel produced a mean transverse tensile strength of 82.7 Mpa (12.0 ksi). Weibull parameterization of the data was possible, but due to variability in raw material and/or manufacturing, more replicates are needed for greater confidence. Three-point flex fatigue testing of the smallest configuration was performed on 59 specimens at various levels of the mean static transverse tensile strength using an R ratio of 0.1 and a frequency of 20 Hz. A great deal of scatter was seen in the data. The majority of specimens failed near the center loading roller. To determine whether the scatter in the fatigue data is due to variability in raw material and/or the manufacturing process, additional testing should be performed on panels manufactured from different sources.

  1. Radioactive Doses - Predicted and Actual - and Likely Health Effects.

    PubMed

    Nagataki, S; Takamura, N

    2016-04-01

    Five years have passed since the nuclear accident at Fukushima Daiichi Nuclear Power Stations on 11 March 2011. Here we refer to reports from international organisations as sources of predicted values obtained from environmental monitoring and dose estimation models, and reports from various institutes in Japan are used as sources of individual actual values. The World Health Organization, based on information available up to 11 September 2011 (and published in 2012), reported that characteristic effective doses in the first year after the accident, to all age groups, were estimated to be in the 10-50 mSv dose band in example locations in evacuation areas. Estimated characteristic thyroid doses to infants in Namie Town were within the 100-200 mSv dose band. A report from the United Nations Scientific Committee on the Effects of Atomic Radiation published in 2014 shows that the effective dose received by adults in evacuation areas during the first year after the accident was 1.1-13 mSv. The absorbed dose to the thyroid in evacuated settlements was 7.2-35 mSv in adults and 15-83 mSv in 1-year-old infants. Individual external radiation exposure in the initial 4 months after the accident, estimated by superimposing individual behaviour data on to a daily dose rate map, was less than 3 mSv in 93.9% of residents (maximum 15 mSv) in evacuation areas. Actual individual thyroid equivalent doses were less than 15 mSv in 98.8% of children (maximum 25 mSv) in evacuation areas. When uncertainty exists in dose estimation models, it may be sensible to err on the side of caution, and final estimated doses are often much greater than actual radiation doses. However, overestimation of the dose at the time of an accident has a great influence on the psychology of residents. More than 100 000 residents have not returned to the evacuation areas 5 years after the Fukushima accident because of the social and mental effects during the initial period of the disaster. Estimates of

  2. Radioactive Doses - Predicted and Actual - and Likely Health Effects.

    PubMed

    Nagataki, S; Takamura, N

    2016-04-01

    Five years have passed since the nuclear accident at Fukushima Daiichi Nuclear Power Stations on 11 March 2011. Here we refer to reports from international organisations as sources of predicted values obtained from environmental monitoring and dose estimation models, and reports from various institutes in Japan are used as sources of individual actual values. The World Health Organization, based on information available up to 11 September 2011 (and published in 2012), reported that characteristic effective doses in the first year after the accident, to all age groups, were estimated to be in the 10-50 mSv dose band in example locations in evacuation areas. Estimated characteristic thyroid doses to infants in Namie Town were within the 100-200 mSv dose band. A report from the United Nations Scientific Committee on the Effects of Atomic Radiation published in 2014 shows that the effective dose received by adults in evacuation areas during the first year after the accident was 1.1-13 mSv. The absorbed dose to the thyroid in evacuated settlements was 7.2-35 mSv in adults and 15-83 mSv in 1-year-old infants. Individual external radiation exposure in the initial 4 months after the accident, estimated by superimposing individual behaviour data on to a daily dose rate map, was less than 3 mSv in 93.9% of residents (maximum 15 mSv) in evacuation areas. Actual individual thyroid equivalent doses were less than 15 mSv in 98.8% of children (maximum 25 mSv) in evacuation areas. When uncertainty exists in dose estimation models, it may be sensible to err on the side of caution, and final estimated doses are often much greater than actual radiation doses. However, overestimation of the dose at the time of an accident has a great influence on the psychology of residents. More than 100 000 residents have not returned to the evacuation areas 5 years after the Fukushima accident because of the social and mental effects during the initial period of the disaster. Estimates of

  3. Experimental determination of TRIP-parameter K for mild- and high-strength low-alloy steels and a super martensitic filler material.

    PubMed

    Neubert, Sebastian; Pittner, Andreas; Rethmeier, Michael

    2016-01-01

    A combined experimental numerical approach is applied to determine the transformation induced plasticity (TRIP)-parameter K for different strength low-alloy steels of grade S355J2+N and S960QL as well as the super martensitic filler CN13-4-IG containing 13 wt% chromium and 4 wt% nickel. The thermo-physical analyses were conducted using a Gleeble (®) 3500 facility. The thermal histories of the specimens to be tested were extracted from corresponding simulations of a real gas metal arc weldment. In contrast to common TRIP-experiments which are based on complex specimens a simple flat specimen was utilized together with an engineering evaluation method. The evaluation method was validated with literature values for the TRIP-parameter. It could be shown that the proposed approach enables a correct description of the TRIP behavior.

  4. Experimental determination of TRIP-parameter K for mild- and high-strength low-alloy steels and a super martensitic filler material.

    PubMed

    Neubert, Sebastian; Pittner, Andreas; Rethmeier, Michael

    2016-01-01

    A combined experimental numerical approach is applied to determine the transformation induced plasticity (TRIP)-parameter K for different strength low-alloy steels of grade S355J2+N and S960QL as well as the super martensitic filler CN13-4-IG containing 13 wt% chromium and 4 wt% nickel. The thermo-physical analyses were conducted using a Gleeble (®) 3500 facility. The thermal histories of the specimens to be tested were extracted from corresponding simulations of a real gas metal arc weldment. In contrast to common TRIP-experiments which are based on complex specimens a simple flat specimen was utilized together with an engineering evaluation method. The evaluation method was validated with literature values for the TRIP-parameter. It could be shown that the proposed approach enables a correct description of the TRIP behavior. PMID:27386237

  5. Theoretical and experimental study of the diffuse transmission of light through highly concentrated absorbing and scattering materials. Part I: Monte-Carlo simulations

    NASA Astrophysics Data System (ADS)

    Bressel, L.; Reich, O.

    2014-10-01

    In many technical materials and commercial products like sunscreen or paint high particle and absorber concentrations are present. An important parameter for slabs of these materials is the diffuse transmission of light, which quantifies the total amount of directly and diffusely transmitted light. Due to the high content of scattering particles not only multiple scattering but also additional dependent scattering occurs. Hence, simple analytical models cannot be applied to calculate the diffuse transmission. In this work a Monte-Carlo program for the calculation of the diffuse transmission of light through dispersions in slab-like geometry containing high concentrations of scattering particles and absorbers is presented and discussed in detail. Mie theory is applied for the calculation of the scattering properties of the samples. Additionally, dependent scattering is considered in two different models, the well-known hard sphere model in the Percus-Yevick approximation (HSPYA) and the Yukawa model in the Mean Spherical Approximation (YMSA). Comparative experiments will show the accurateness of the program as well as its applicability to real samples [1].

  6. Principles of establishing material cycling with a high degree of closure in the experimental model of a BTLSS intended for a rated "fraction of a human"

    NASA Astrophysics Data System (ADS)

    Tikhomirov, Alexander A.; Ushakova, Sofya; Velichko, Vladimir; Tikhomirova, Natalia; Shikhov, Valentin; Trifonov, Sergey V.

    2016-07-01

    A promising way to develop future biotechnical life support systems (BTLSS) is to construct experimental models and establish the cycling intended for a fraction of a human. Being of relatively low cost, such models provide an opportunity to test effectively closed process that could be further transferred to the real BTLSS with humans. Researchers of the IBP SB RAS are developing an adequate BTLSS model with the loops closed to a high degree. To attain high closure of mass exchange processes, plants in the phototrophic compartment are cultivated under intensive lighting conditions, created by using modern LED irradiators of enhanced power, equipped with lens optics. The higher plant compartment has been renewed and broadened by including soybean plants, which improve the vegetable part of the human diet and make it more diverse. It is very important that the operation of the physicochemical installation for waste mineralization fully matches the composition of the atmosphere of plant growth chambers: the purified gaseous components of this installation enter the common atmosphere of the system, without causing any deviations from the norm in the gaseous composition. This proves the eco-friendliness of the developed physicochemical method of waste mineralization and shows that the gaseous components resulting from waste mineralization can be included in the system mass exchange. A system for including human respiration into the gas exchange of the BTLSS has been developed and tested; the associated gas exchange and water exchange dynamics have been analyzed. Results of the functioning of the experimental model of the BTLSS for several months are proposed for discussion in order to get insight into the formation of dynamic characteristics of cycling processes and factors determining them. The study was supported by the grant of the Russian Science Foundation (Project 14-14-00599) and carried out at the IBP SB RAS.

  7. Photovoltaic performance models: an evaluation with actual field data

    NASA Astrophysics Data System (ADS)

    TamizhMani, Govindasamy; Ishioye, John-Paul; Voropayev, Arseniy; Kang, Yi

    2008-08-01

    Prediction of energy production is crucial to the design and installation of the building integrated photovoltaic systems. This prediction should be attainable based on the commonly available parameters such as system size, orientation and tilt angle. Several commercially available as well as free downloadable software tools exist to predict energy production. Six software models have been evaluated in this study and they are: PV Watts, PVsyst, MAUI, Clean Power Estimator, Solar Advisor Model (SAM) and RETScreen. This evaluation has been done by comparing the monthly, seasonaly and annually predicted data with the actual, field data obtained over a year period on a large number of residential PV systems ranging between 2 and 3 kWdc. All the systems are located in Arizona, within the Phoenix metropolitan area which lies at latitude 33° North, and longitude 112 West, and are all connected to the electrical grid.

  8. Hawaii requires actual exposure to validate distress claims.

    PubMed

    1999-10-29

    The "actual exposure" rule can now be applied in Hawaii to cases involving the recovery of damages for HIV exposure even if the virus is not transmitted. This ruling came as a result of the case of three airport baggage handlers who were exposed to a leaking container of HIV-positive blood. The Hawaii Supreme Court ruled that a plaintiff has to prove that the exposure involves a "scientifically accepted" method of transmission and that the fluid in question contained HIV. Furthermore, the court ruled, any liability for mental distress is limited to the time between discovery of contamination and confirmation that no infection resulted. With current testing standards, the time period between discovery and a negative test result is approximately 3 to 6 months.

  9. Illinois adopts 'actual exposure' rule for distress claims.

    PubMed

    1998-10-30

    The Illinois Supreme Court has ruled that plaintiffs must prove actual exposure to HIV if they hope to recover damages in fear-of-AIDS lawsuits. Most state courts accept that as the standard for determining if a claim is legitimate. Two cases were addressed in the ruling. In one case, [name removed] sued Dr. [name removed] and the estate of [name removed]'s late partner, who died of AIDS-related complications in 1991. While [name removed] was employed by the doctors, she cut herself on a used scalpel in a waste basket. The scalpel was not tested, but she has had three HIV tests which have shown negative results. The other case involved six people who sued Northwestern University after learning that a dental student who treated them was HIV-positive. The six people have also tested negative.

  10. Throwing patterns used by collegiate baseball players in actual games.

    PubMed

    Barrett, David D; Burton, Allen W

    2002-03-01

    The form of 3,684 throws made by 100 players in 7 collegiate baseball games was examined in relation to position, distance, and active and inactive situations. All throws made from the first pitch to the last out for 94 half innings were videotaped from the stands. The results showed that the interrater reliability of task, environment, and performance measures were all acceptable to excellent (percentage of agreement was at least 80%), indicating that qualitative aspects of throwing can be reliably measured in an actual sport context. Alternatives to the most advanced pattern were observed at least half the time for catchers and infielders at most distances in both active and inactive situations andfor pitchers and outfielders only in inactive situations.

  11. Catalytic combustion of actual low and medium heating value gases

    NASA Technical Reports Server (NTRS)

    Bulzan, D. L.

    1982-01-01

    Catalytic combustion of both low and medium heating value gases using actual coal derived gases obtained from operating gasifiers was demonstrated. A fixed bed gasifier with a complete product gas cleanup system was operated in an air blown mode to produce low heating value gas. A fluidized bed gasifier with a water quench product gas cleanup system was operated in both an air enriched and an oxygen blown mode to produce low and medium, heating value gas. Noble metal catalytic reactors were evaluated in 12 cm flow diameter test rigs on both low and medium heating value gases. Combustion efficiencies greater than 99.5% were obtained with all coal derived gaseous fuels. The NOx emissions ranged from 0.2 to 4 g NO2 kg fuel.

  12. Actual leisure participation of Norwegian adolescents with Down syndrome.

    PubMed

    Dolva, Anne-Stine; Kleiven, Jo; Kollstad, Marit

    2014-02-01

    This article reports the actual participation in leisure activities by a sample of Norwegian adolescents with Down syndrome aged 14. Representing a first generation to grow up in a relatively inclusive context, they live with their families, attend mainstream schools, and are part of common community life. Leisure information was obtained in individual, structured parent interviews, and added to existing longitudinal data from a project following the sample. Generally, the leisure activity may be viewed as varying along a continuum-reaching from formal, organized, and assisted activity participation outside home, to informal, self-organized, and independent participation at home. Formal leisure activities were either organized "for all" or "adapted for disabled." The adolescents' leisure appears as active and social. However, social participation largely involved parents and family, while socializing with other adolescents mainly took place within formal activities adapted for disabled. Clearly, formal and informal activities provide rather different opportunities for social encounters and assistance. PMID:24515503

  13. An evaluation of contractor projected and actual costs

    NASA Technical Reports Server (NTRS)

    Kwiatkowski, K. A.; Buffalano, C.

    1974-01-01

    GSFC contractors with cost-plus contracts provide cost estimates for each of the next four quarters on a quarterly basis. Actual expenditures over a two-year period were compared to the estimates, and the data were sorted in different ways to answer several questions and give quantification to observations, such as how much does the accuracy of estimates degrade as they are made further into the future? Are estimates made for small dollar amounts more accurate than for large dollar estimates? Other government agencies and private companies with cost-plus contracts may be interested in this analysis as potential methods of contract management for their organizations. It provides them with the different methods one organization is beginning to use to control costs.

  14. Actual and desired computer literacy among allied health students.

    PubMed

    Agho, A O; Williams, A M

    1995-01-01

    The purpose of this study was to examine the level of computer literacy among allied health students, with specific focus on physical therapy, occupational therapy, and respiratory therapy students, and to investigate the perceived differences between actual computer literacy and desired computer literacy. Two established measurement instruments were used to collect data from a sample of 377 allied health students. T-tests and Pearson product-moment correlations were conducted to analyze the data. Results show that allied health students take very few computer courses, but they are generally aware of the applications of computers in the practice of allied health and they desire a higher level of computer literacy than they currently have.

  15. Non-actual motion: phenomenological analysis and linguistic evidence.

    PubMed

    Blomberg, Johan; Zlatev, Jordan

    2015-09-01

    Sentences with motion verbs describing static situations have been seen as evidence that language and cognition are geared toward dynamism and change (Talmy in Toward a cognitive semantics, MIT Press, Cambridge, 2000; Langacker in Concept, image, and symbol: the cognitive basis of grammar, Mouton de Gruyter, Berlin and New York, 1990). Different concepts have been used in the literature, e.g., fictive motion, subjective motion and abstract motion to denote this. Based on phenomenological analysis, we reinterpret such concepts as reflecting different motivations for the use of such constructions (Blomberg and Zlatev in Phenom Cogn Sci 13(3):395-418, 2014). To highlight the multifaceted character of the phenomenon, we propose the concept non-actual motion (NAM), which we argue is more compatible with the situated cognition approach than explanations such as "mental simulation" (e.g., Matlock in Studies in linguistic motivation, Mouton de Gruyter, Berlin, 2004). We investigate the expression of NAM by means of a picture-based elicitation task with speakers of Swedish, French and Thai. Pictures represented figures that either afford human motion or not (±afford); crossed with this, the figure extended either across the picture from a third-person perspective (3 pp) or from a first-person perspective (1 pp). All picture types elicited NAM-sentences with the combination [+afford, 1 pp] producing most NAM-sentences in all three languages. NAM-descriptions also conformed to language-specific patterns for the expression of actual motion. We conclude that NAM shows interaction between pre-linguistic motivations and language-specific conventions.

  16. Flexible Material Systems Testing

    NASA Technical Reports Server (NTRS)

    Lin, John K.; Shook, Lauren S.; Ware, Joanne S.; Welch, Joseph V.

    2010-01-01

    An experimental program has been undertaken to better characterize the stress-strain characteristics of flexible material systems to support a NASA ground test program for inflatable decelerator material technology. A goal of the current study is to investigate experimental methods for the characterization of coated woven material stiffness. This type of experimental mechanics data would eventually be used to define the material inputs of fluid-structure interaction simulation models. The test methodologies chosen for this stress-strain characterization are presented along with the experimental results.

  17. Experimental Design for a Sponge-Wipe Study to Relate the Recovery Efficiency and False Negative Rate to the Concentration of a Bacillus anthracis Surrogate for Six Surface Materials

    SciTech Connect

    Piepel, Gregory F.; Amidan, Brett G.; Krauter, Paula; Einfeld, Wayne

    2010-12-16

    Two concerns were raised by the Government Accountability Office following the 2001 building contaminations via letters containing Bacillus anthracis (BA). These included the: 1) lack of validated sampling methods, and 2) need to use statistical sampling to quantify the confidence of no contamination when all samples have negative results. Critical to addressing these concerns is quantifying the probability of correct detection (PCD) (or equivalently the false negative rate FNR = 1 - PCD). The PCD/FNR may depend on the 1) method of contaminant deposition, 2) surface concentration of the contaminant, 3) surface material being sampled, 4) sample collection method, 5) sample storage/transportation conditions, 6) sample processing method, and 7) sample analytical method. A review of the literature found 17 laboratory studies that focused on swab, wipe, or vacuum samples collected from a variety of surface materials contaminated by BA or a surrogate, and used culture methods to determine the surface contaminant concentration. These studies quantified performance of the sampling and analysis methods in terms of recovery efficiency (RE) and not PCD/FNR (which left a major gap in available information). Quantifying the PCD/FNR under a variety of conditions is a key aspect of validating sample and analysis methods, and also for calculating the confidence in characterization or clearance decisions based on a statistical sampling plan. A laboratory study was planned to partially fill the gap in PCD/FNR results. This report documents the experimental design developed by Pacific Northwest National Laboratory and Sandia National Laboratories (SNL) for a sponge-wipe method. The study will investigate the effects on key response variables from six surface materials contaminated with eight surface concentrations of a BA surrogate (Bacillus atrophaeus). The key response variables include measures of the contamination on test coupons of surface materials tested, contamination

  18. Experimental Design for a Sponge-Wipe Study to Relate the Recovery Efficiency and False Negative Rate to the Concentration of a Bacillus anthracis Surrogate for Six Surface Materials

    SciTech Connect

    Piepel, Gregory F.; Amidan, Brett G.; Krauter, Paula; Einfeld, Wayne

    2011-05-01

    Two concerns were raised by the Government Accountability Office following the 2001 building contaminations via letters containing Bacillus anthracis (BA). These included the: 1) lack of validated sampling methods, and 2) need to use statistical sampling to quantify the confidence of no contamination when all samples have negative results. Critical to addressing these concerns is quantifying the false negative rate (FNR). The FNR may depend on the 1) method of contaminant deposition, 2) surface concentration of the contaminant, 3) surface material being sampled, 4) sample collection method, 5) sample storage/transportation conditions, 6) sample processing method, and 7) sample analytical method. A review of the literature found 17 laboratory studies that focused on swab, wipe, or vacuum samples collected from a variety of surface materials contaminated by BA or a surrogate, and used culture methods to determine the surface contaminant concentration. These studies quantified performance of the sampling and analysis methods in terms of recovery efficiency (RE) and not FNR (which left a major gap in available information). Quantifying the FNR under a variety of conditions is a key aspect of validating sample and analysis methods, and also for calculating the confidence in characterization or clearance decisions based on a statistical sampling plan. A laboratory study was planned to partially fill the gap in FNR results. This report documents the experimental design developed by Pacific Northwest National Laboratory and Sandia National Laboratories (SNL) for a sponge-wipe method. The testing was performed by SNL and is now completed. The study investigated the effects on key response variables from six surface materials contaminated with eight surface concentrations of a BA surrogate (Bacillus atrophaeus). The key response variables include measures of the contamination on test coupons of surface materials tested, contamination recovered from coupons by sponge

  19. Physics associated with cavitation induced material damage

    NASA Technical Reports Server (NTRS)

    Peterson, F. B.

    1974-01-01

    The role of cavitation in mechanical failure is discussed. Some of the most common types of material damage associated with the presence of cavitation are surface material removal, delamination and structural vibration. This occurs in external flows such as on propellers, hydrofoils, and high speed non-lifting surfaces. In internal flows, pipe bends, inlets, constructions, pumps and turbines are typical. Nominally nonflowing liquids are also susceptible in, for example, strong acoustic fields and high energy particle detectors. For flowing systems, Bernoulli's equation shows how a local pressure is reduced as the fluid's velocity is increased. At sufficiently high velocities, a tension can actually develop and this has, in fact, been demonstrated experimentally. Once the pressure is reduced below the fluid vapor pressure a vapor cavity can be nucleated. Various aspects of this process are simply shown by considering the flow over a lifting surface.

  20. Experimental study of turned and grit-blasted screw-shaped implants with special emphasis on effects of blasting material and surface topography.

    PubMed

    Wennerberg, A; Albrektsson, T; Johansson, C; Andersson, B

    1996-01-01

    In the rabbit tibia, commercially pure titanium implants blasted with 25-microns Al2O3 and TiO2 particles respectively were inserted and studied with respect to removal torque and histomorphometry. In the rabbit femur, as-machined implants and implants blasted with 75-microns Al2O3 particles were histomorphometrically compared. Before implant insertion, the differently produced surface topographies were characterized numerically and visually. The tibial implants blasted with different materials and the same sized (25 microns) blasting particles demonstrated similar results. Comparing implants blasted with 75-microns Al2O3 particles to as-machined implants, the blasted specimens exhibited a statistically significant higher bone-to-metal contact after 12 weeks in the rabbit bone. PMID:8962942

  1. Different modes of internalization of proteins associated with adhaerens junctions and desmosomes: experimental separation of lateral contacts induces endocytosis of desmosomal plaque material.

    PubMed Central

    Kartenbeck, J; Schmid, E; Franke, W W; Geiger, B

    1982-01-01

    The distribution and fate of two junctional complexes, zonula adhaerens and desmosomes, after dissociation of cell-cell contacts is described in MDBK cells. Junctions were split between adjacent cells by treatment with EGTA and proteins associated with the plaques of zonulae adhaerentes and desmosomes were localized by immunological methods. Splitting of these junctions is accompanied by the dislocation of desmosomal plaque protein from the cell periphery and its distribution in punctate arrays over the whole cytoplasm. By contrast, vinculin associated with zonulae adhaerentes is still seen at early times (0.5-1 h) in a conspicuous belt-like structure which, however, is displaced from the plasma membrane. Strong vinculin staining is maintained on leading edges of free cell surfaces. Electron microscopy of EGTA-treated cells exposed to colloidal gold particles reveals the disappearance of junctional structures from the cell periphery and the concomitant appearance of a distinct class of gold particle-containing vesicles which are coated by dense plaques. These vesicle plaques react with antibodies to desmosomal plaque proteins and are associated with filaments of the cytokeratin type. In the same cells, extended dense aggregates are seen which are most probably the membrane-detached vinculin-rich material from the zonula adhaerens . The experiments show that, upon release from their junction-mediated connections with adjacent cells, major proteins associated with the cytoplasmic side of the junctions remain, for several hours, clustered within plaques displaced from the cell surface. While plaque material of adhaerens junctions containing vinculin is recovered in large belt-like aggregates, desmosomal plaque protein remains attached to membrane structures and appears on distinct vesicles endocytotically formed from half-desmosomal equivalents.(ABSTRACT TRUNCATED AT 250 WORDS) Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. PMID:6821357

  2. Experimental study of PFCs erosion and eroded material deposition under ITER-like transient loads at the plasma gun facility QSPA-T

    NASA Astrophysics Data System (ADS)

    Klimov, N.; Podkovyrov, V.; Zhitlukhin, A.; Kovalenko, D.; Linke, J.; Pintsuk, G.; Landman, I.; Pestchanyi, S.; Bazylev, B.; Janeschitz, G.; Loarte, A.; Merola, M.; Hirai, T.; Federici, G.; Riccardi, B.; Mazul, I.; Giniyatulin, R.; Khimchenko, L.; Koidan, V.

    2011-08-01

    The paper concerns experimental investigations of plasma facing components erosion under the plasma heat loads expected in ITER divertor during transient events such as the Type I Edge-Localized Modes and the disruptions. The experiments were carried out at the TRINITI plasma gun QSPA-T. The carbon fiber composite and tungsten macrobrush targets designed for ITER were exposed to multiple plasma pulses of duration 0.5 ms and deposited energy in the range of 0.2-2.5 MJ/m2. Between some of the pulses the eroded surface was analyzed with profilometric measurements and electron microscopy. The CFC erosion is determined mainly by damages to the PAN-fibers. While the energy increases from 0.2 to 2.4 MJ/m2 the removed layer of PAN-fibers area increases from 0.01 to 10 μm per pulse. The erosion of tungsten (pure and lanthanum oxide-doped tungsten) is shown to be determined mainly by crack formation, melt layer movement and droplets ejection.

  3. Comparison of experimental approaches to study selective properties of thick phase-amplitude holograms recorded in materials with diffusion-based formation mechanisms

    NASA Astrophysics Data System (ADS)

    Borisov, Vladimir; Klepinina, Mariia; Veniaminov, Andrey; Angervaks, Aleksandr; Shcheulin, Aleksandr; Ryskin, Aleksandr

    2016-04-01

    Volume holographic gratings, both transmission and reflection-type, may be employed as one-dimensional pho- tonic crystals. More complex two- and three-dimensional holographic photonic-crystalline structures can be recorded using several properly organized beams. As compared to colloidal photonic crystals, their holographic counterparts let minimize distortions caused by multiple inner boundaries of the media. Unfortunately, it's still hard to analyze spectral response of holographic structures. This work presents the results of thick holographic gratings analysis based on spectral-angular selectivity contours approximation. The gratings were recorded in an additively colored fluorite crystal and a glassy polymer doped with phenanthrenequinone (PQ-PMMA). The two materials known as promising candidates for 3D diffraction optics including photonic crystals, employ diffusion-based mechanisms of grating formation. The surfaces of spectral-angular selectivity were obtained in a single scan using a white-light LED, rotable table and a matrix spectrometer. The data expressed as 3D plots make apparent visual estimation of the grating phase/amplitude nature, noninearity of recording, etc., and provide sufficient information for numerical analysis. The grating recorded in the crystal was found to be a mixed phase-amplitude one, with different contributions of refractive index and absorbance modulation at different wavelengths, and demonstrated three diffraction orders corresponding to its three spatial harmonics originating from intrinsically nonlinear diffusion-drift recording mechanism. Contrastingly, the grating in the polymeric medium appeared purely phase and linearly recorded.

  4. Theoretical Analyses and Experimental Investigations of Selective Carbothermal Reactions of Vanadium-Bearing Titanomagnetite Concentrates for Preparation of Iron-Based Wear-Resistant Material

    NASA Astrophysics Data System (ADS)

    Zhang, Guangming; Feng, Keqin; Yue, Huifang

    2016-09-01

    Based on FACTSage® software, this paper focuses on the thermodynamic calculations of selective carbothermal reactions of vanadium-bearing titanomagnetite concentrates for preparing iron-based wear-resistant material directly from vanadium-bearing titanomagnetite concentrates. The calculations show that it was most likely to generate metallic iron, titanium carbide and vanadium carbide among all possible carbothermal reactions of vanadium-bearing titanomagnetite concentrates in a vacuum of 10 Pa. The equilibrium composition calculations indicate that Fe3O4 can be reduced to metallic iron by carbon above 400°C, FeTiO3 can be converted into TiC by carbon above 800°C and V2O5 can be converted into VC by carbon above 600°C in a vacuum of 10 Pa. The investigations demonstrated that the percentage of ferrous oxides reduced to metallic iron was about 96%, the conversion percentage of FeTiO3 into TiC was about 75% and the conversion percentage of V2O5 into VC was about 94% after the selective carbothermal reactions of vanadium-bearing titanomagnetite concentrates at 1300°C for 3 h in a vacuum of 10 Pa.

  5. Theoretical Analyses and Experimental Investigations of Selective Carbothermal Reactions of Vanadium-Bearing Titanomagnetite Concentrates for Preparation of Iron-Based Wear-Resistant Material

    NASA Astrophysics Data System (ADS)

    Zhang, Guangming; Feng, Keqin; Yue, Huifang

    2016-07-01

    Based on FACTSage® software, this paper focuses on the thermodynamic calculations of selective carbothermal reactions of vanadium-bearing titanomagnetite concentrates for preparing iron-based wear-resistant material directly from vanadium-bearing titanomagnetite concentrates. The calculations show that it was most likely to generate metallic iron, titanium carbide and vanadium carbide among all possible carbothermal reactions of vanadium-bearing titanomagnetite concentrates in a vacuum of 10 Pa. The equilibrium composition calculations indicate that Fe3O4 can be reduced to metallic iron by carbon above 400°C, FeTiO3 can be converted into TiC by carbon above 800°C and V2O5 can be converted into VC by carbon above 600°C in a vacuum of 10 Pa. The investigations demonstrated that the percentage of ferrous oxides reduced to metallic iron was about 96%, the conversion percentage of FeTiO3 into TiC was about 75% and the conversion percentage of V2O5 into VC was about 94% after the selective carbothermal reactions of vanadium-bearing titanomagnetite concentrates at 1300°C for 3 h in a vacuum of 10 Pa.

  6. Tutorial on Actual Space Environmental Hazards For Space Systems (Invited)

    NASA Astrophysics Data System (ADS)

    Mazur, J. E.; Fennell, J. F.; Guild, T. B.; O'Brien, T. P.

    2013-12-01

    It has become common in the space science community to conduct research on diverse physical phenomena because they are thought to contribute to space weather. However, satellites contend with only three primary environmental hazards: single event effects, vehicle charging, and total dose, and not every physical phenomenon that occurs in space contributes in substantial ways to create these hazards. One consequence of the mismatch between actual threats and all-encompassing research is the often-described gap between research and operations; another is the creation of forecasts that provide no actionable information for design engineers or spacecraft operators. An example of the latter is the physics of magnetic field emergence on the Sun; the phenomenon is relevant to the formation and launch of coronal mass ejections and is also causally related to the solar energetic particles that may get accelerated in the interplanetary shock. Unfortunately for the research community, the engineering community mitigates the space weather threat (single-event effects from heavy ions above ~50 MeV/nucleon) with a worst-case specification of the environment and not with a prediction. Worst-case definition requires data mining of past events, while predictions involve large-scale systems science from the Sun to the Earth that is compelling for scientists and their funding agencies but not actionable for design or for most operations. Differing priorities among different space-faring organizations only compounds the confusion over what science research is relevant. Solar particle impacts to human crew arise mainly from the total ionizing dose from the solar protons, so the priority for prediction in the human spaceflight community is therefore much different than in the unmanned satellite community, while both communities refer to the fundamental phenomenon as space weather. Our goal in this paper is the presentation of a brief tutorial on the primary space environmental phenomena

  7. Effect of low-level laser therapy irradiation and Bio-Oss graft material on the osteogenesis process in rabbit calvarium defects: a double blind experimental study.

    PubMed

    Rasouli Ghahroudi, Amir Alireza; Rokn, Amir Reza; Kalhori, Katayoun A M; Khorsand, Afshin; Pournabi, Alireza; Pinheiro, A L B; Fekrazad, Reza

    2014-05-01

    This study aims to assess the effect of low-level laser therapy (LLLT) irradiation and Bio-Oss graft material on the osteogenesis process in the rabbit calvarium defects. Twelve white male New Zealand rabbits were included in this study. Four 8-mm diameter identical defects were prepared on each rabbit's calvarium. One site was left as an untreated control (C), the second site was filled with Bio-Oss (B), the third site was treated with laser irradiation (L), and the fourth site treated with Bio-Oss and laser irradiation (B + L). In the laser group, a diode laser (wavelength 810 nm, output power 300 mW, irradiation mode CW, energy density 4 J/cm2) was applied immediately after surgery and then one other day for the next 20 days. After 4 and 8 weeks, the animals were sacrificed and histological and histomorphometric examinations were performed and the data were subjected to Friedman and repeated measurements ANOVA tests. Significant differences were not found regarding inflammation severity, foreign body reactions, and vitality of newly formed bone on 4th and 8th week after operation. The mean amount of new bone was 15.83 and 18.5% in the controls on the 4th and 8th week; 27.66 and 25.16% in the laser-irradiated group; 35.0 and 41.83% in Bio-Oss and 41.83 and 47.0% in the laser + Bio-Oss treated specimens with significant statistical differences (p <0.05). Application of LLLT in combination with Bio-Oss® can promote bone healing. Therefore, LLLT may be clinically beneficial in promoting bone formation in skeletal defects.

  8. Gender, smiling, and witness credibility in actual trials.

    PubMed

    Nagle, Jacklyn E; Brodsky, Stanley L; Weeter, Kaycee

    2014-01-01

    It has been acknowledged that females exhibit more smiling behaviors than males, but there has been little attention to this gender difference in the courtroom. Although both male and female witnesses exhibit smiling behaviors, there has been no research examining the subsequent effect of gender and smiling on witness credibility. This study used naturalistic observation to examine smiling behaviors and credibility in actual witnesses testifying in court. Raters assessed the smiling behaviors and credibility (as measured by the Witness Credibility Scale) of 32 male and female witnesses testifying in trials in a mid-sized Southern city. "Credibility raters" rated the perceived likeability, trustworthiness, confidence, knowledge, and overall credibility of the witnesses using the Witness Credibility Scale. "Smile raters" noted smiling frequency and types, including speaking/expressive and listening/receptive smiles. Gender was found to affect perceived trustworthiness ratings, in which male witnesses were seen as more trustworthy than female witnesses. No significant differences were found in the smiling frequency for male and female witnesses. However, the presence of smiling was found to contribute to perceived likeability of a witness. Smiling female witnesses were found to be more likeable than smiling male and non-smiling female witnesses.

  9. How to actualize potential: a bioecological approach to talent development.

    PubMed

    Ceci, Stephen J; Williams-Ceci, Sterling; Williams, Wendy M

    2016-08-01

    Bioecological theory posits three interacting principles to explain developmental outcomes such as fluctuating achievement levels and changing heritability coefficients. Here, we apply the theory to the domain of talent development, by reviewing short-term and long-term cognitive interventions. We argue that macro-level analyses of cultural practices (e.g., matrilineal inheritance and property ownership) and national systems of education are consistent with the bioecological theory; when the findings from these analyses are unpacked, the engines that drive them are so-called proximal processes. This finding has implications for the design and delivery of instruction and the development of talent. We argue that talent is fostered by the same three bioecological mechanisms that explain the actualization of genetic potential. We conclude by discussing several self-descriptions and personal narratives by gifted students in which they spontaneously refer to these bioecological mechanisms in their own talent-development processes. Similar testimonials have been documented by historic talent researchers such as Benjamin Bloom, noting the importance of continual adjustments in feedback.

  10. Gender, smiling, and witness credibility in actual trials.

    PubMed

    Nagle, Jacklyn E; Brodsky, Stanley L; Weeter, Kaycee

    2014-01-01

    It has been acknowledged that females exhibit more smiling behaviors than males, but there has been little attention to this gender difference in the courtroom. Although both male and female witnesses exhibit smiling behaviors, there has been no research examining the subsequent effect of gender and smiling on witness credibility. This study used naturalistic observation to examine smiling behaviors and credibility in actual witnesses testifying in court. Raters assessed the smiling behaviors and credibility (as measured by the Witness Credibility Scale) of 32 male and female witnesses testifying in trials in a mid-sized Southern city. "Credibility raters" rated the perceived likeability, trustworthiness, confidence, knowledge, and overall credibility of the witnesses using the Witness Credibility Scale. "Smile raters" noted smiling frequency and types, including speaking/expressive and listening/receptive smiles. Gender was found to affect perceived trustworthiness ratings, in which male witnesses were seen as more trustworthy than female witnesses. No significant differences were found in the smiling frequency for male and female witnesses. However, the presence of smiling was found to contribute to perceived likeability of a witness. Smiling female witnesses were found to be more likeable than smiling male and non-smiling female witnesses. PMID:24634058

  11. Comparisons of pilot performance in simulated and actual flight.

    PubMed

    Billings, C E; Gerke, R J; Wick, R L

    1975-03-01

    Five highly experienced professional pilots performed instrument landing system approaches under simulated instrument flight conditions in a Cessna 172 airplane and in a Link-Singer GAT-1 simulator while under the influence of orally administered secobarbital (0, 100, and 200 mg). Tracking performance in two axes and airspeed control were evaluated continuously during each approach. The data from the airplane and simulator were compared. Error and RMS variability were about half as large in the simulator as in the airplane. The observed data were more strongly associated with the drug level in the simulator than in the airplane. Further, the drug-related effects were more consistent in the simulator. Improvement in performance suggestive of learning effects were seen in the simulator, but not in actual flight. It is concluded that the GAT-1 simulator is a useful and sensitive device for studies of the effects of mild stress on pilot performance, but extrapolation of simulator data to the flight environment must be approached with considerable caution.

  12. Alternate corrections for estimating actual wetland evapotranspiration from potential evapotranspiration

    USGS Publications Warehouse

    Barclay, Shoemaker W.; Sumner, D.M.

    2006-01-01

    Corrections can be used to estimate actual wetland evapotranspiration (AET) from potential evapotranspiration (PET) as a means to define the hydrology of wetland areas. Many alternate parameterizations for correction coefficients for three PET equations are presented, covering a wide range of possible data-availability scenarios. At nine sites in the wetland Everglades of south Florida, USA, the relatively complex PET Penman equation was corrected to daily total AET with smaller standard errors than the PET simple and Priestley-Taylor equations. The simpler equations, however, required less data (and thus less funding for instrumentation), with the possibility of being corrected to AET with slightly larger, comparable, or even smaller standard errors. Air temperature generally corrected PET simple most effectively to wetland AET, while wetland stage and humidity generally corrected PET Priestley-Taylor and Penman most effectively to wetland AET. Stage was identified for PET Priestley-Taylor and Penman as the data type with the most correction ability at sites that are dry part of each year or dry part of some years. Finally, although surface water generally was readily available at each monitoring site, AET was not occurring at potential rates, as conceptually expected under well-watered conditions. Apparently, factors other than water availability, such as atmospheric and stomata resistances to vapor transport, also were limiting the PET rate. ?? 2006, The Society of Wetland Scientists.

  13. Reconciling actual and perceived rates of predation by domestic cats

    PubMed Central

    McDonald, Jennifer L; Maclean, Mairead; Evans, Matthew R; Hodgson, Dave J

    2015-01-01

    The predation of wildlife by domestic cats (Felis catus) is a complex problem: Cats are popular companion animals in modern society but are also acknowledged predators of birds, herpetofauna, invertebrates, and small mammals. A comprehensive understanding of this conservation issue demands an understanding of both the ecological consequence of owning a domestic cat and the attitudes of cat owners. Here, we determine whether cat owners are aware of the predatory behavior of their cats, using data collected from 86 cats in two UK villages. We examine whether the amount of prey their cat returns influences the attitudes of 45 cat owners toward the broader issue of domestic cat predation. We also contribute to the wider understanding of physiological, spatial, and behavioral drivers of prey returns among cats. We find an association between actual prey returns and owner predictions at the coarse scale of predatory/nonpredatory behavior, but no correlation between the observed and predicted prey-return rates among predatory cats. Cat owners generally disagreed with the statement that cats are harmful to wildlife, and disfavored all mitigation options apart from neutering. These attitudes were uncorrelated with the predatory behavior of their cats. Cat owners failed to perceive the magnitude of their cats’ impacts on wildlife and were not influenced by ecological information. Management options for the mitigation of cat predation appear unlikely to work if they focus on “predation awareness” campaigns or restrictions of cat freedom. PMID:26306163

  14. A comprehensive approach to actual polychlorinated biphenyls environmental contamination.

    PubMed

    Risso, F; Magherini, A; Ottonelli, M; Magi, E; Lottici, S; Maggiolo, S; Garbarino, M; Narizzano, R

    2016-05-01

    Worldwide polychlorinated biphenyls (PCBs) pollution is due to complex mixtures with high number of congeners, making the determination of total PCBs in the environment an open challenge. Because the bulk of PCBs production was made of Aroclor mixtures, this analysis is usually faced by the empirical mixture identification via visual inspection of the chromatogram. However, the identification reliability is questionable, as patterns in real samples are strongly affected by the frequent occurrence of more than one mixture. Our approach is based on the determination of a limited number of congeners chosen to enable objective criteria for Aroclor identification, summing up the advantages of congener-specific analysis with the ones of total PCBs determination. A quantitative relationship is established between congeners and any single mixture, or mixtures combination, leading to the identification of the actual contamination composition. The approach, due to its generality, allows the use of different sets of congeners and any technical mixture, including the non-Aroclor ones. The results confirm that PCB environmental pollution in northern Italy is based on Aroclor. Our methodology represents an important tool to understand the source and fate of the PCBs contamination.

  15. Is transferring an educational innovation actually a process of transformation?

    PubMed

    Varpio, Lara; Bell, Robert; Hollingworth, Gary; Jalali, Alireza; Haidet, Paul; Levine, Ruth; Regehr, Glenn

    2012-08-01

    Recent debates question the extent to which adopting an educational innovation requires compromise between the innovation's original design and the adoption site's context. Through compromises, the innovation's fundamental principles may be transferred, transformed, or abandoned. This paper analyzes such compromises during the piloting of Team-Based Learning (TBL). We ask: When is the process of transferring an innovation actually a process of transformation? This study is an autoethnography of our research team's implementation process. Autoethnographies are personalized accounts where authors draw on their own experiences to extend understanding of a particular topic. To conduct this autoethnography, we used an in-depth, interactive interview with the piloting clinician educator. In the analysis of TBL's fundamental principles, some aspects of the principles transferred easily, while others were transformed. Analysis raised concerns that the transformations threatened the foundational principles of TBL. While an educational innovation's techniques may seem to be surface structures, they are realizations of deeper fundamental principles. The fundamental principles are themselves realizations of the innovation's foundational philosophy. When techniques and/or principles are modified to a context, it is important to analyze if the modifications continue to uphold the innovation's philosophy. PMID:21725841

  16. Is transferring an educational innovation actually a process of transformation?

    PubMed

    Varpio, Lara; Bell, Robert; Hollingworth, Gary; Jalali, Alireza; Haidet, Paul; Levine, Ruth; Regehr, Glenn

    2012-08-01

    Recent debates question the extent to which adopting an educational innovation requires compromise between the innovation's original design and the adoption site's context. Through compromises, the innovation's fundamental principles may be transferred, transformed, or abandoned. This paper analyzes such compromises during the piloting of Team-Based Learning (TBL). We ask: When is the process of transferring an innovation actually a process of transformation? This study is an autoethnography of our research team's implementation process. Autoethnographies are personalized accounts where authors draw on their own experiences to extend understanding of a particular topic. To conduct this autoethnography, we used an in-depth, interactive interview with the piloting clinician educator. In the analysis of TBL's fundamental principles, some aspects of the principles transferred easily, while others were transformed. Analysis raised concerns that the transformations threatened the foundational principles of TBL. While an educational innovation's techniques may seem to be surface structures, they are realizations of deeper fundamental principles. The fundamental principles are themselves realizations of the innovation's foundational philosophy. When techniques and/or principles are modified to a context, it is important to analyze if the modifications continue to uphold the innovation's philosophy.

  17. West Virginia US Department of Energy experimental program to stimulate competitive research. Section 2: Human resource development; Section 3: Carbon-based structural materials research cluster; Section 3: Data parallel algorithms for scientific computing

    SciTech Connect

    Not Available

    1994-02-02

    This report consists of three separate but related reports. They are (1) Human Resource Development, (2) Carbon-based Structural Materials Research Cluster, and (3) Data Parallel Algorithms for Scientific Computing. To meet the objectives of the Human Resource Development plan, the plan includes K--12 enrichment activities, undergraduate research opportunities for students at the state`s two Historically Black Colleges and Universities, graduate research through cluster assistantships and through a traineeship program targeted specifically to minorities, women and the disabled, and faculty development through participation in research clusters. One research cluster is the chemistry and physics of carbon-based materials. The objective of this cluster is to develop a self-sustaining group of researchers in carbon-based materials research within the institutions of higher education in the state of West Virginia. The projects will involve analysis of cokes, graphites and other carbons in order to understand the properties that provide desirable structural characteristics including resistance to oxidation, levels of anisotropy and structural characteristics of the carbons themselves. In the proposed cluster on parallel algorithms, research by four WVU faculty and three state liberal arts college faculty are: (1) modeling of self-organized critical systems by cellular automata; (2) multiprefix algorithms and fat-free embeddings; (3) offline and online partitioning of data computation; and (4) manipulating and rendering three dimensional objects. This cluster furthers the state Experimental Program to Stimulate Competitive Research plan by building on existing strengths at WVU in parallel algorithms.

  18. Identification of flow patterns by neutron noise analysis during actual coolant boiling in thin rectangular channels

    SciTech Connect

    Kozma, R.; van Dam, H.; Hoogenboom, J.E. )

    1992-10-01

    The primary objective of this paper is to introduce results of coolant boiling experiments in a simulated materials test reactor-type fuel assembly with plate fuel in an actual reactor environment. The experiments have been performed in the Hoger Onderwijs Reactor (HOR) research reactor at the Interfaculty Reactor Institute, Delft, The Netherlands. In the analysis, noise signals of self-powered neutron detectors located in the neighborhood of the boiling region and thermocouple in the channel wall and in the coolant are used. Flow patterns in the boiling coolant have been identified by means of analysis of probability density functions and power spectral densities of neutron noise. It is shown that boiling has an oscillating character due to partial channel blockage caused by steam slugs generated periodically between the plates. The observed phenomenon can serve as a basis for a boiling detection method in reactors with plate-type fuels.

  19. Establishing seasonal chronicles of actual evapotranspiration under sloping conditions

    NASA Astrophysics Data System (ADS)

    Zitouna Chebbi, R.; Prévot, L.; Jacob, F.; Voltz, M.

    2012-04-01

    Estimation of daily and seasonal actual evapotranspiration (ETa) is strongly needed for hydrological and agricultural purposes. Although the eddy covariance method is well suited for such estimation of land surface fluxes, this method suffers from limitations when establishing long time series. Missing data are often encountered, resulting from bad meteorological conditions, rejection by quality control tests, power failures… Numerous gap fill techniques have been proposed in the literature but there applicability in sloping conditions is not well known. In order to estimate ETa over long periods (agricultural cycle) on crops cultivated in sloping areas, a pluri-annual experiment was conducted in the Kamech catchment, located in North-eastern Tunisia. This Mediterranean site is characterized by a large heterogeneity in topography, soils and crops. Land surface fluxes were measured using eddy covariance systems. Measurements were collected on the two opposite sides of the Kamech V-shaped catchment, within small fields having slopes steeper than 5%. During three different years, four crops were studied: durum wheat, oat, fava bean and pasture. The topography of the catchment and the wind regime induced upslope and downslope flows over the study fields. In this study, we showed that gap filling of the turbulent fluxes (sensible and latent heat) can be obtained through linear regressions against net radiation. To account for the effect of the topography, linear regressions were calibrated by distinguishing upslope and downslope flows. This significantly improved the quality of the reconstructed data over 30 minute intervals. This gap filling technique also improved the energy balance closure at the daily time scale. As a result, seasonal chronicles of daily ETa throughout the growth cycle of the study crops in the Kamech watershed were established, thus providing useful information about the water use of annual crops in a semi-arid rainfed and hilly area.

  20. Using lysimeters to test the Penman Monteith actual evapotranspiration.

    NASA Astrophysics Data System (ADS)

    Ben Asher, Jiftah; Volinski, Roman; Zilberman, Arkadi; Bar Yosef, Beni; Silber, Avner

    2015-04-01

    Differences in actual transpiration (ETa) of banana plants were quantified in a lysimeter experiment. ETA was computed using instantaneous data from two weighing lysimeters and compared to PM (Penman-Monteith) model for ETa. Two critical problems were faced in this test. A) Estimating canopy and aerodynamic resistances ("rc" and "ra" respectively ) and B) converting the lysimeter changes in water volume ( LYv cm3 ) to ETa length units ( cm ). The two unknowns " rc" and "ra" were obtained from continuous measurements of the differences between canopy and air temperature (Tc - Ta). This difference was established by means of the infrared thermometry which was followed by numerical and analytical calculation of ETa using the modification suggested by R. Jackson to the PM model. The conversion of lysimeter volumetric units (LYv) to ETa length units was derived from the slope of cumulative LYv/ETa. This relationship was significantly linear (r2=0.97and 0.98.). Its slope was interpreted as "evaporating leaf area" which accounted for 1.8E4 cm2 in lysimeter 1 and 2.3E4 cm2.in lysimeter 2 . The comparison between LYv and PM model was acceptable even under very low ETa. The average of two lysimeters was 1.1mm/day (1.4 mm/day , LYv 1 and 0.8 LYv 2) while ETa calculated on the basis of PM model was 1.2 mm/day. It was concluded that although lysimeters are most accurate systems to measure ETa one of its disadvantages ( beside the high cost) is the volumetric output that in many cases should be supported by a one dimensional energy balance system. The PM model was found to be a reliable complementary tool to convert lysimeters volumetric output into conventional length units of ETa.