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Sample records for equivalent material sensitivity

  1. Comparison of pinhole collimator materials based on sensitivity equivalence.

    PubMed

    Bom, Victor; Goorden, Marlies; Beekman, Freek

    2011-06-07

    Pinhole SPECT often provides an excellent resolution sensitivity trade-off for radionuclide imaging compared to SPECT with parallel holes, particularly when imaging small experimental animals like rodents. High absorption pinhole materials are often chosen because of their low edge penetration and therefore good system resolution. Capturing more photons in the edges however results in decreased system sensitivity if the pinhole diameter remains the same, which may partly undo the beneficial effect on the resolution. In the search for an optimal trade-off we have compared pinhole projection data and reconstructed images of different materials with pinhole aperture diameters adjusted to obtain equal sensitivity. Monte Carlo calculations modeling the transmission, penetration and scattering of gamma radiation in single pinholes of uranium, gold, tungsten and lead were performed for a range of pinhole opening angles, diameters and gamma ray energies. In addition, reconstructed images of a hot rod phantom were determined for a multipinhole SPECT system and for a system that can image the 511 keV annihilation photons of positron emitting tracers with clustered pinholes. Our results indicate that, under the condition of equal sensitivity, tungsten and for SPECT also lead pinholes perform just as well as gold and uranium ones, indicating that a significant cost reduction can be achieved in pinhole collimator manufacturing while the use of rare or impractical materials can be avoided.

  2. The effect of high-resolution parallel-hole collimator materials with a pixelated semiconductor SPECT system at equivalent sensitivities: Monte Carlo simulation studies

    NASA Astrophysics Data System (ADS)

    Lee, Young-Jin; Kim, Dae-Hong; Kim, Hee-Joung

    2014-04-01

    In nuclear medicine, the use of a pixelated semiconductor detector with cadmium telluride (CdTe) or cadmium zinc telluride (CdZnTe) is of growing interest for new devices. Especially, the spatial resolution can be improved by using a pixelated parallel-hole collimator with equal holes and pixel sizes based on the above-mentioned detector. High-absorption and high-stopping-power pixelated parallel-hole collimator materials are often chosen because of their good spatial resolution. Capturing more gamma rays, however, may result in decreased sensitivity with the same collimator geometric designs. Therefore, a trade-off between spatial resolution and sensitivity is very important in nuclear medicine imaging. The purpose of this study was to compare spatial resolutions using a pixelated semiconductor single photon emission computed tomography (SPECT) system with lead, tungsten, gold, and depleted uranium pixelated parallel-hole collimators at equal sensitivity. We performed a simulation study of the PID 350 (Ajat Oy Ltd., Finland) CdTe pixelated semiconductor detector (pixel size: 0.35 × 0.35 mm2) by using a Geant4 Application for Tomographic Emission (GATE) simulation. Spatial resolutions were measured with different collimator materials at equivalent sensitivities. Additionally, hot-rod phantom images were acquired for each source-to-collimator distance by using a GATE simulation. At equivalent sensitivities, measured averages of the full width at half maximum (FWHM) using lead, tungsten, and gold were 4.32, 2.93, and 2.23% higher than that of depleted uranium, respectively. Furthermore, for the full width at tenth maximum (FWTM), measured averages when using lead, tungsten, and gold were 6.29, 4.10, and 2.65% higher than that of depleted uranium, respectively. Although, the spatial resolution showed little differences among the different pixelated parallel-hole collimator materials, lower absorption and stopping power materials such as lead and tungsten had

  3. Explosive materials equivalency, test methods and evaluation

    NASA Technical Reports Server (NTRS)

    Koger, D. M.; Mcintyre, F. L.

    1980-01-01

    Attention is given to concepts of explosive equivalency of energetic materials based on specific airblast parameters. A description is provided of a wide bandwidth high accuracy instrumentation system which has been used extensively in obtaining pressure time profiles of energetic materials. The object of the considered test method is to determine the maximum output from the detonation of explosive materials in terms of airblast overpressure and positive impulse. The measured pressure and impulse values are compared with known characteristics of hemispherical TNT data to determine the equivalency of the test material in relation to TNT. An investigation shows that meaningful comparisons between various explosives and a standard reference material such as TNT should be based upon the same parameters. The tests should be conducted under the same conditions.

  4. Detection of ultraviolet radiation using tissue equivalent radiochromic gel materials

    NASA Astrophysics Data System (ADS)

    Bero, M. A.; Abukassem, I.

    2009-05-01

    Ferrous Xylenol-orange Gelatin gel (FXG) is known to be sensitive to ionising radiation such as γ and X-rays. The effect of ionising radiation is to produce an increase in the absorption over a wide region of the visible spectrum, which is proportional to the absorbed dose. This study demonstrates that FXG gel is sensitive to ultraviolet radiation and therefore it could functions as UV detector. Short exposure to UV radiation produces linear increase in absorption measured at 550nm, however high doses of UV cause the ion indicator colour to fad away in a manner proportional to the incident UV energy. Light absorbance increase at the rate of 1.1% per minute of irradiation was monitored. The exposure level at which the detector has linear response is comparable to the natural summer UV radiation. Evaluating the UV ability to pass through tissue equivalent gel materials shows that most of the UV gets absorbed in the first 5mm of the gel materials, which demonstrate the damaging effects of this radiation type on human skin and eyes. It was concluded that FXG gel dosimeter has the potential to offer a simple, passive ultraviolet radiation detector with sensitivity suitable to measure and visualises the natural sunlight UV exposure directly by watching the materials colour changes.

  5. Wave propagation in equivalent continuums representing truss lattice materials

    SciTech Connect

    Messner, Mark C.; Barham, Matthew I.; Kumar, Mukul; Barton, Nathan R.

    2015-07-29

    Stiffness scales linearly with density in stretch-dominated lattice meta-materials offering the possibility of very light yet very stiff structures. Current additive manufacturing techniques can assemble structures consisting of these lattice materials, but the design of such structures will require accurate, efficient simulation techniques. Equivalent continuum models have several advantages over discrete truss models of stretch dominated lattices, including computational efficiency and ease of model construction. However, the development an equivalent model suitable for representing the dynamic response of a periodic truss is complicated by microinertial effects. This paper derives a dynamic equivalent continuum model for periodic truss structures and verifies it against detailed finite element simulations. The model must incorporate microinertial effects to accurately reproduce long-wavelength characteristics of the response such as anisotropic elastic soundspeeds. The formulation presented here also improves upon previous work by preserving equilibrium at truss joints for affine lattice deformation and by improving numerical stability by eliminating vertices in the effective yield surface.

  6. Equivalent-Continuum Modeling of Nano-Structured Materials

    NASA Technical Reports Server (NTRS)

    Odegard, Gregory M.; Gates, Thomas S.; Nicholson, Lee M.; Wise, Kristopher E.

    2001-01-01

    A method has been developed for modeling structure-property relationships of nano-structured materials. This method serves as a link between computational chemistry and solid mechanics by substituting discrete molecular structures with an equivalent-continuum model. It has been shown that this substitution may be accomplished by equating the vibrational potential energy of a nano-structured material with the strain energy of representative truss and continuum models. As an important example with direct application to the development and characterization of single-walled carbon nanotubes, the model has been applied to determine the effective continuum geometry of a graphene sheet. A representative volume element of the equivalent-continuum model has been developed with an effective thickness. This effective thickness has been shown to be similar to, but slightly smaller than, the interatomic spacing of graphite.

  7. Water-equivalent fiber radiation dosimeter with two scintillating materials

    PubMed Central

    Qin, Zhuang; Hu, Yaosheng; Ma, Yu; Lin, Wei; Luo, Xianping; Zhao, Wenhui; Sun, Weimin; Zhang, Daxin; Chen, Ziyin; Wang, Boran; Lewis, Elfed

    2016-01-01

    An inorganic scintillating material plastic optical fiber (POF) dosimeter for measuring ionizing radiation during radiotherapy applications is reported. It is necessary that an ideal dosimeter exhibits many desirable qualities, including water equivalence, energy independence, reproducibility, dose linearity. There has been much recent research concerning inorganic dosimeters. However, little reference has been made to date of the depth-dose characteristics of dosimeter materials. In the case of inorganic scintillating materials, they are predominantly non water-equivalent, with their effective atomic weight (Zeff) being typically much greater than that of water. This has been a barrier in preventing inorganic scintillating material dosimeter from being used in actual clinical applications. In this paper, we propose a parallel-paired fiber light guide structure to solve this problem. Two different inorganic scintillating materials are embedded separately in the parallel-paired fiber. It is shown that the information of water depth and absorbed dose at the point of measurement can be extracted by utilizing their different depth-dose properties. PMID:28018715

  8. Water-equivalent fiber radiation dosimeter with two scintillating materials.

    PubMed

    Qin, Zhuang; Hu, Yaosheng; Ma, Yu; Lin, Wei; Luo, Xianping; Zhao, Wenhui; Sun, Weimin; Zhang, Daxin; Chen, Ziyin; Wang, Boran; Lewis, Elfed

    2016-12-01

    An inorganic scintillating material plastic optical fiber (POF) dosimeter for measuring ionizing radiation during radiotherapy applications is reported. It is necessary that an ideal dosimeter exhibits many desirable qualities, including water equivalence, energy independence, reproducibility, dose linearity. There has been much recent research concerning inorganic dosimeters. However, little reference has been made to date of the depth-dose characteristics of dosimeter materials. In the case of inorganic scintillating materials, they are predominantly non water-equivalent, with their effective atomic weight (Zeff) being typically much greater than that of water. This has been a barrier in preventing inorganic scintillating material dosimeter from being used in actual clinical applications. In this paper, we propose a parallel-paired fiber light guide structure to solve this problem. Two different inorganic scintillating materials are embedded separately in the parallel-paired fiber. It is shown that the information of water depth and absorbed dose at the point of measurement can be extracted by utilizing their different depth-dose properties.

  9. Ignition Delay of Combustible Materials in Normoxic Equivalent Environments

    NASA Technical Reports Server (NTRS)

    McAllister, Sara; Fernandez-Pello, Carlos; Ruff, Gary; Urban, David

    2009-01-01

    Material flammability is an important factor in determining the pressure and composition (fraction of oxygen and nitrogen) of the atmosphere in the habitable volume of exploration vehicles and habitats. The method chosen in this work to quantify the flammability of a material is by its ease of ignition. The ignition delay time was defined as the time it takes a combustible material to ignite after it has been exposed to an external heat flux. Previous work in the Forced Ignition and Spread Test (FIST) apparatus has shown that the ignition delay in the currently proposed space exploration atmosphere (approximately 58.6 kPa and32% oxygen concentration) is reduced by 27% compared to the standard atmosphere used in the Space Shuttle and Space Station. In order to determine whether there is a safer environment in terms of material flammability, a series of piloted ignition delay tests using polymethylmethacrylate (PMMA) was conducted in the FIST apparatus to extend the work over a range of possible exploration atmospheres. The exploration atmospheres considered were the normoxic equivalents, i.e. reduced pressure conditions with a constant partial pressure of oxygen. The ignition delay time was seen to decrease as the pressure was reduced along the normoxic curve. The minimum ignition delay observed in the normoxic equivalent environments was nearly 30% lower than in standard atmospheric conditions. The ignition delay in the proposed exploration atmosphere is only slightly larger than this minimum. Interms of material flammability, normoxic environments with a higher pressure relative to the proposed pressure would be desired.

  10. Ignition Delay of Combustible Materials in Normoxic Equivalent Environments

    NASA Technical Reports Server (NTRS)

    McAllister, Sara; Fernandez-Pello, Carlos; Ruff, Gary; Urban, David

    2009-01-01

    Material flammability is an important factor in determining the pressure and composition (fraction of oxygen and nitrogen) of the atmosphere in the habitable volume of exploration vehicles and habitats. The method chosen in this work to quantify the flammability of a material is by its ease of ignition. The ignition delay time was defined as the time it takes a combustible material to ignite after it has been exposed to an external heat flux. Previous work in the Forced Ignition and Spread Test (FIST) apparatus has shown that the ignition delay in the currently proposed space exploration atmosphere (approximately 58.6 kPa and32% oxygen concentration) is reduced by 27% compared to the standard atmosphere used in the Space Shuttle and Space Station. In order to determine whether there is a safer environment in terms of material flammability, a series of piloted ignition delay tests using polymethylmethacrylate (PMMA) was conducted in the FIST apparatus to extend the work over a range of possible exploration atmospheres. The exploration atmospheres considered were the normoxic equivalents, i.e. reduced pressure conditions with a constant partial pressure of oxygen. The ignition delay time was seen to decrease as the pressure was reduced along the normoxic curve. The minimum ignition delay observed in the normoxic equivalent environments was nearly 30% lower than in standard atmospheric conditions. The ignition delay in the proposed exploration atmosphere is only slightly larger than this minimum. Interms of material flammability, normoxic environments with a higher pressure relative to the proposed pressure would be desired.

  11. Shock Sensitivity of energetic materials

    NASA Technical Reports Server (NTRS)

    Kim, K.

    1980-01-01

    Viscoplastic deformation is examined as the principal source of hot energy. Some shock sensitivity data on a proposed model is explained. A hollow sphere model is used to approximate complex porous matrix of energetic materials. Two pieces of shock sensitivity data are qualitatively compared with results of the proposed model. The first is the p2 tau law. The second is the desensitization of energetic materials by a ramp wave applied stress. An approach to improve the model based on experimental observations is outlined.

  12. Improved MAGIC gel for higher sensitivity and elemental tissue equivalent 3D dosimetry

    SciTech Connect

    Zhu Xuping; Reese, Timothy G.; Crowley, Elizabeth M.; El Fakhri, Georges

    2010-01-15

    Purpose: Polymer-based gel dosimeter (MAGIC type) is a preferable phantom material for PET range verification of proton beam therapy. However, improvement in elemental tissue equivalency (specifically O/C ratio) is very desirable to ensure realistic time-activity measurements. Methods: Glucose and urea was added to the original MAGIC formulation to adjust the O/C ratio. The dose responses of the new formulations were tested with MRI transverse relaxation rate (R2) measurements. Results: The new ingredients improved not only the elemental composition but also the sensitivity of the MAGIC gel. The O/C ratios of our new gels agree with that of soft tissue within 1%. The slopes of dose response curves were 1.6-2.7 times larger with glucose. The melting point also increased by 5 deg. C. Further addition of urea resulted in a similar slope but with an increased intercept and a decreased melting point. Conclusions: Our improved MAGIC gel formulations have higher sensitivity and better elemental tissue equivalency for 3D dosimetry applications involving nuclear reactions.

  13. Focused neutron beam dose deposition profiles in tissue equivalent materials: a pilot study for BNCT

    NASA Astrophysics Data System (ADS)

    Mayer, Rulon R.; Welsh, James; Chen-Mayer, Huaiyu H.

    1997-02-01

    Boron Neutron Capture Therapy (BNCT) has been limited by the inability to direct neutrons toward the therapeutic target and away from sensitive normal tissues. The recently developed Kumakhov lens has focused a broad incident low energy neutron beam in air to a sub-mm spot. This study examines the radiation does distribution of a converging beam passing through tissue equivalent materials. A neutron beam exiting a focusing lens is directed toward a stack of thin radiochromic media sandwiched between plastic sheets. The depth dose and beam profile within the tissue equivalent materials are determined by optical scanning and image processing of the individual radiochromic media sheets, a polymer based dosimetry medium which darkens upon exposure to ionizing radiation. The alpha particle emission from boron is examined by substituting a plastic sheet with a 6Li enriched lithium carbonate sheet positioned at the focal plane. The information will help determine the feasibility of applying the focused neutron beam to BNCT for therapy.

  14. Factorizing the motion sensitivity function into equivalent input noise and calculation efficiency.

    PubMed

    Allard, Rémy; Arleo, Angelo

    2017-01-01

    The photopic motion sensitivity function of the energy-based motion system is band-pass peaking around 8 Hz. Using an external noise paradigm to factorize the sensitivity into equivalent input noise and calculation efficiency, the present study investigated if the variation in photopic motion sensitivity as a function of the temporal frequency is due to a variation of equivalent input noise (e.g., early temporal filtering) or calculation efficiency (ability to select and integrate motion). For various temporal frequencies, contrast thresholds for a direction discrimination task were measured in presence and absence of noise. Up to 15 Hz, the sensitivity variation was mainly due to a variation of equivalent input noise and little variation in calculation efficiency was observed. The sensitivity fall-off at very high temporal frequencies (from 15 to 30 Hz) was due to a combination of a drop of calculation efficiency and a rise of equivalent input noise. A control experiment in which an artificial temporal integration was applied to the stimulus showed that an early temporal filter (generally assumed to affect equivalent input noise, not calculation efficiency) could impair both the calculation efficiency and equivalent input noise at very high temporal frequencies. We conclude that at the photopic luminance intensity tested, the variation of motion sensitivity as a function of the temporal frequency was mainly due to early temporal filtering, not to the ability to select and integrate motion. More specifically, we conclude that photopic motion sensitivity at high temporal frequencies is limited by internal noise occurring after the transduction process (i.e., neural noise), not by quantal noise resulting from the probabilistic absorption of photons by the photoreceptors as previously suggested.

  15. Ignition delay of combustible materials in normoxic equivalent environments

    Treesearch

    Sara McAllister; Carlos Fernandez-Pello; Gary Ruff; David Urban

    2009-01-01

    Material flammability is an important factor in determining the pressure and composition (fraction of oxygen and nitrogen) of the atmosphere in the habitable volume of exploration vehicles and habitats. The method chosen in this work to quantify the flammability of a material is by its ease of ignition. The ignition delay time was defined as the time it takes a...

  16. The development of psychometrically equivalent Cantonese speech audiometry materials.

    PubMed

    Nissen, Shawn L; Harris, Richard W; Channell, Ron W; Conklin, Brooke; Kim, Misty; Wong, Lena

    2011-03-01

    The aim of this study was to develop and psychometrically evaluate speech audiometry materials that can be used to measure word recognition (WR) and speech recognition testing (SRT) in quiet for native speakers of Cantonese. Commonly used bisyllabic and trisyllabic Cantonese words were digitally recorded by native male and female talkers and then evaluated by twenty normal-hearing Cantonese listeners. The recorded bisyllabic words were psychometrically evaluated and arranged into four WR lists and eight half-lists that are relatively homogeneous in audibility. Using logistic regression, SRT materials were developed by selecting 28 trisyllabic words with relatively steep psychometric functions and digitally adjusting their intensity to match the listeners' mean pure-tone average. The mean psychometric slopes for the WR materials were 7.5%/dB for the male talker and 7.6%/dB for the female talker, with no statistically significant differences between the lists or half-lists. At intensity levels required for 50% intelligibility, the mean psychometric slopes of the male and female talker SRT materials were 14.5%/dB and 14.9 %/dB, respectively. High-quality digital recordings of Cantonese speech audiometric WR and SRT materials were developed and validated in this study. These materials are available on compact disc, indexed by talker gender.

  17. Investigating the Strain Rate Effect on the Equivalent Initial Crack Size in a Particulate Composite Material

    DTIC Science & Technology

    2002-03-06

    Equivalent Initial Flaw Size Distribution," Proceeding of the 18th...Symposium of ICAF, Melbourne, Australia, 385-403. (2) Yang, J.N., Manning, S.D., and Newman, J.C., Jr., (1997), " Equivalent Initial Flaw Size Distribution for...Kyoto, Japan. (3) Liu, C. T. and Yang, J. N. (2000), "Determination of Equivalent Initial Flaw Size in a Particulate Composite Material," Proceeding

  18. X-ray Sensitive Material

    DTIC Science & Technology

    2015-12-01

    The research resulted in a composite material that holds a quasi-permanent electric charge and rapidly discharges the electric charge upon X-ray...temperature extremes encountered during processing and potential application. (U) The result of these efforts was a composite material that would hold a...quasi-permanent electric charge and rapidly discharge the electric charge upon X-ray exposure. The composite material combined the properties of an

  19. Determination of noise equivalent reflectance for a multispectral scanner: A scanner sensitivity study

    NASA Technical Reports Server (NTRS)

    Gibbons, D. E.; Richard, R. R.

    1979-01-01

    The methods used to calculate the sensitivity parameter noise equivalent reflectance of a remote-sensing scanner are explored, and the results are compared with values measured over calibrated test sites. Data were acquired on four occasions covering a span of 4 years and providing various atmospheric conditions. One of the calculated values was based on assumed atmospheric conditions, whereas two others were based on atmospheric models. Results indicate that the assumed atmospheric conditions provide useful answers adequate for many purposes. A nomograph was developed to indicate sensitivity variations due to geographic location, time of day, and season.

  20. Protective coatings for sensitive materials

    DOEpatents

    Egert, C.M.

    1997-08-05

    An enhanced protective coating is disclosed to prevent interaction between constituents of the environment and devices that can be damaged by those constituents. This coating is provided by applying a synergistic combination of diffusion barrier and physical barrier materials. These materials can be, for example, in the form of a plurality of layers of a diffusion barrier and a physical barrier, with these barrier layers being alternated. Further protection in certain instances is provided by including at least one layer of a getter material to actually react with one or more of the deleterious constituents. The coating is illustrated by using alternating layers of an organic coating (such as Parylene-C{trademark}) as the diffusion barrier, and a metal coating (such as aluminum) as the physical barrier. For best results there needs to be more than one of at least one of the constituent layers. 4 figs.

  1. Protective coatings for sensitive materials

    DOEpatents

    Egert, Charles M.

    1997-01-01

    An enhanced protective coating to prevent interaction between constituents of the environment and devices that can be damaged by those constituents. This coating is provided by applying a synergistic combination of diffusion barrier and physical barrier materials. These materials can be, for example, in the form of a plurality of layers of a diffusion barrier and a physical barrier, with these barrier layers being alternated. Further protection in certain instances is provided by including at least one layer of a getter material to actually react with one or more of the deleterious constituents. The coating is illustrated by using alternating layers of an organic coating (such as Parylene-C.TM.) as the diffusion barrier, and a metal coating (such as aluminum) as the physical barrier. For best results there needs to be more than one of at least one of the constituent layers.

  2. Contrast sensitivity loss with aging: sampling efficiency and equivalent noise at different spatial frequencies

    NASA Astrophysics Data System (ADS)

    Pardhan, Shahina

    2004-02-01

    The relative contributions of optical and neural factors to the decrease in visual function with aging were investigated by measurement of contrast detection at three different spatial frequencies, in the presence of external noise, on young and older subjects. Contrast detection in noise functions allows two parameters to be measured: sampling efficiency, which indicates neural changes, and equivalent noise, which demonstrates optical effects. Contrast thresholds were measured in the presence of four levels (including zero) of externally added visual noise. Measurements were obtained from eight young and eight older visually normal observers. Compared with young subjects, older subjects showed significantly (p<0.05) lower sampling efficiencies at spatial frequencies of 1 and 4 cycles per degree (c/deg) and significantly higher equivalent noise levels for gratings of 10 c/deg. Neural and optical factors affect contrast sensitivity loss with aging differently, depending on the spatial frequency tested, implying the existence of different mechanisms.

  3. Equivalent Electromagnetic Constants for Microwave Application to Composite Materials for the Multi-Scale Problem

    PubMed Central

    Fujisaki, Keisuke; Ikeda, Tomoyuki

    2013-01-01

    To connect different scale models in the multi-scale problem of microwave use, equivalent material constants were researched numerically by a three-dimensional electromagnetic field, taking into account eddy current and displacement current. A volume averaged method and a standing wave method were used to introduce the equivalent material constants; water particles and aluminum particles are used as composite materials. Consumed electrical power is used for the evaluation. Water particles have the same equivalent material constants for both methods; the same electrical power is obtained for both the precise model (micro-model) and the homogeneous model (macro-model). However, aluminum particles have dissimilar equivalent material constants for both methods; different electric power is obtained for both models. The varying electromagnetic phenomena are derived from the expression of eddy current. For small electrical conductivity such as water, the macro-current which flows in the macro-model and the micro-current which flows in the micro-model express the same electromagnetic phenomena. However, for large electrical conductivity such as aluminum, the macro-current and micro-current express different electromagnetic phenomena. The eddy current which is observed in the micro-model is not expressed by the macro-model. Therefore, the equivalent material constant derived from the volume averaged method and the standing wave method is applicable to water with a small electrical conductivity, although not applicable to aluminum with a large electrical conductivity. PMID:28788395

  4. Equivalent Electromagnetic Constants for Microwave Application to Composite Materials for the Multi-Scale Problem.

    PubMed

    Fujisaki, Keisuke; Ikeda, Tomoyuki

    2013-11-21

    To connect different scale models in the multi-scale problem of microwave use, equivalent material constants were researched numerically by a three-dimensional electromagnetic field, taking into account eddy current and displacement current. A volume averaged method and a standing wave method were used to introduce the equivalent material constants; water particles and aluminum particles are used as composite materials. Consumed electrical power is used for the evaluation. Water particles have the same equivalent material constants for both methods; the same electrical power is obtained for both the precise model (micro-model) and the homogeneous model (macro-model). However, aluminum particles have dissimilar equivalent material constants for both methods; different electric power is obtained for both models. The varying electromagnetic phenomena are derived from the expression of eddy current. For small electrical conductivity such as water, the macro-current which flows in the macro-model and the micro-current which flows in the micro-model express the same electromagnetic phenomena. However, for large electrical conductivity such as aluminum, the macro-current and micro-current express different electromagnetic phenomena. The eddy current which is observed in the micro-model is not expressed by the macro-model. Therefore, the equivalent material constant derived from the volume averaged method and the standing wave method is applicable to water with a small electrical conductivity, although not applicable to aluminum with a large electrical conductivity.

  5. Analytic Sensitivities for Shape Optimization in Equivalent Plate Structural Wing Models

    NASA Technical Reports Server (NTRS)

    Livne, Eli

    1994-01-01

    Equivalent plate modeling techniques based on Ritz analysis with simple polynomials prove to be efficient tools for structural modeling of wings in the preliminary design stage. Accuracy problems are encountered, however, when these models are used to obtain finite difference behavior sensitivities with respect to planform shape. The accuracy problems are associated with the poor numerical conditioning of static and eigenvalue equations. As higher-order polynomials are being used to Improve the analysis itself, the more sensitive is the finite difference derivative to the step size used. This article describes a formulation of wing equivalent plate modeling in which it is simple to obtain analytic, explicit expressions for stiffness and mass matrix elements without the need to perform numerical integration. This formulation leads naturally to analytic expressions for the derivatives of displacements, stresses, and natural frequencies with respect to shape design variables. This article examines the accuracy of finite difference derivatives compared with the analytic derivatives, and shows that In some cases it is impossible to obtain any information of value by finite differences. Analytic sensitivities, in this case, are still sufficiently accurate for design optimization.

  6. Derivation of Accident-Specific Material-at-Risk Equivalency Factors

    SciTech Connect

    Jason P. Andrus; Dr. Chad L. Pope

    2012-05-01

    A novel method for calculating material at risk (MAR) dose equivalency developed at the Idaho National Laboratory (INL) now allows for increased utilization of dose equivalency for facility MAR control. This method involves near-real time accounting for the use of accident and material specific release and transport. It utilizes all information from the committed effective dose equation and the five factor source term equation to derive dose equivalency factors which can be used to establish an overall facility or process MAR limit. The equivalency factors allow different nuclide spectrums to be compared for their respective dose consequences by relating them to a specific quantity of an identified reference nuclide. The ability to compare spectrums to a reference limit ensures that MAR limits are in fact bounding instead of attempting to establish a representative or bounding spectrum which may lead to unintended or unanalyzed configurations. This methodology is then coupled with a near real time material tracking system which allows for accurate and timely material composition information and corresponding MAR equivalency values. The development of this approach was driven by the complex nature of processing operations in some INL facilities. This type of approach is ideally suited for facilities and processes where the composition of the MAR and possible release mechanisms change frequently but in well defined fashions and in a batch-type nature.

  7. An epidermal equivalent assay for identification and ranking potency of contact sensitizers

    SciTech Connect

    Gibbs, Susan; Corsini, Emanuela; Spiekstra, Sander W.; Galbiati, Valentina; Fuchs, Horst W.; DeGeorge, George; Troese, Matthew; Hayden, Patrick; Deng, Wei; Roggen, Erwin

    2013-10-15

    The purpose of this study was to explore the possibility of combining the epidermal equivalent (EE) potency assay with the assay which assesses release of interleukin-18 (IL-18) to provide a single test for identification and classification of skin sensitizing chemicals, including chemicals of low water solubility or stability. A protocol was developed using different 3D-epidermal models including in house VUMC model, epiCS® (previously EST1000™), MatTek EpiDerm™ and SkinEthic™ RHE and also the impact of different vehicles (acetone:olive oil 4:1, 1% DMSO, ethanol, water) was investigated. Following topical exposure for 24 h to 17 contact allergens and 13 non-sensitizers a robust increase in IL-18 release was observed only after exposure to contact allergens. A putative prediction model is proposed from data obtained from two laboratories yielding 95% accuracy. Correlating the in vitro EE sensitizer potency data, which assesses the chemical concentration which results in 50% cytotoxicity (EE-EC{sub 50}) with human and animal data showed a superior correlation with human DSA{sub 05} (μg/cm{sup 2}) data (Spearman r = 0.8500; P value (two-tailed) = 0.0061) compared to LLNA data (Spearman r = 0.5968; P value (two-tailed) = 0.0542). DSA{sub 05} = induction dose per skin area that produces a positive response in 5% of the tested population Also a good correlation was observed for release of IL-18 (SI-2) into culture supernatants with human DSA{sub 05} data (Spearman r = 0.8333; P value (two-tailed) = 0.0154). This easily transferable human in vitro assay appears to be very promising, but additional testing of a larger chemical set with the different EE models is required to fully evaluate the utility of this assay and to establish a definitive prediction model. - Highlights: • A potential epidermal equivalent assay to label and classify sensitizers • Il-18 release distinguishes sensitizers from non sensitizers • IL-18 release can rank sensitizer potency

  8. X-ray scattering from human breast tissues and breast-equivalent materials.

    PubMed

    Poletti, M E; Gonçalves, D; Mazzaro, I

    2002-01-07

    The angular distributions of photons scattered by human breast tissues (adipose and glandular) and by eight breast-equivalent materials (water, polymethylmethacrylate, nylon, polyethylene and four commercial breast-equivalent materials simulating different glandular-adipose proportions) have been measured at a photon energy of 17.44 keV (Kalpha-radiation of Mo). Transmission target geometry has been used with an acceptance of +/- 0.6 degrees and an uncertainty of approximately 7%. Experimental molecular form factors were extracted from diffraction patterns normalizing the number of scattered photons with theoretical data in regions where no structure is expected. Linear attenuation coefficients have been measured for all samples at this energy. The results for water, polymethylmethacrylate, nylon and adipose tissue agree with former reported data. The results for human breast tissues at low and medium scattering angle (1-25 degrees, corresponding to the momentum transfer region between 0.2 and 3 nm(-1)) differ from the breast-equivalent materials. The results for adipose tissue are similar to the corresponding values from commercial breast-equivalent materials while the results for glandular tissue are similar to those for water.

  9. Polyurethane as a base for a family of tissue equivalent materials

    SciTech Connect

    Griffith, R.V.

    1980-01-01

    Polyurethane was used as a base material for a wide variety of tissue simulating applications. The technique in fabrication is similar to that of epoxy, however, the end products are generally more flexible for use in applications where flexibility is valuable. The material can be fabricated with relatively small laboratory equipment. The use of polyurethane provides the dosimetrist with the capability of making specific, accurate, on-the-spot tissue equivalent formulations to meet situations which require immediate calibration and response.

  10. Electromagnetic equivalent model for phase conjugate mirror based on the utilization of left-handed material.

    PubMed

    Zheng, Guoan; Ran, Lixin; Yang, Changhuei

    2007-10-17

    An electromagnetic equivalent model for the phase conjugate mirror (PCM) is proposed in this paper. The model is based on the unique property of the isotropic left-handed material (LHM) - the ability of LHM to reverse the phase factors of propagative waves. We show that a PCM interface can be substituted with a LHM-RHM (right-handed material) interface and associated image sources and objects in the LHM. This equivalent model is fully equivalent in the treatment of propagative wave components. However, we note that the presence of evanescent wave components can lead to undesirably surface resonance at the LHM-RHM interface. This artefact can be kept well bounded by introducing a small refractive index mismatch between the LHM and RHM. We demonstrate the usefulness of this model by modelling several representative scenarios of light patterns interacting with a PCM. The simulations were performed by applying the equivalent model to a commercial finite element method (FEM) software. This equivalent model also points to the intriguing possibility of realizing some unique LHM based systems in the optical domain by substituting a PCM in place of a LHM-RHM interface.

  11. Factors Affecting Shock Sensitivity of Energetic Materials

    NASA Astrophysics Data System (ADS)

    Chakravarty, A.; Gifford, M. J.; Greenaway, M. W.; Proud, W. G.; Field, J. E.

    2002-07-01

    An extensive study has been carried out into the relationships between the particle size of a charge, the density to which it is packed, the presence of inert additives and the sensitivity of the charge to different initiating shocks. The critical parameters for two different shock regimes have been found. The long duration shocks are provided by a commercial detonator and the short duration shocks are imparted using laser-driven flyer plates. It has been shown that the order of sensitivity of charges to different shock regimes varies. In particular, ultrafine materials have been shown to be relatively insensitive to long duration low pressure shocks and sensitive to short duration high pressure shocks. The materials that have been studied include HNS, RDX and PETN.

  12. Factors Affecting Shock Sensitivity of Energeticv Materials

    NASA Astrophysics Data System (ADS)

    Chakravarty, Avic; Gifford, Michael John; Greenaway, Martin; Proud, William; Field, John

    2001-06-01

    An extensive study has been carried out into the relationships between the particle size of a charge, the density to which it is packed, the presence of inert additives and the sensitivity of the charge to different initiating shocks. The critical parameters for three different shock regimes have been found. The long duration shocks are provided by a commercial detonator, the medium duration shocks are provided by an electrically driven flyer-plate and the short duration shocks are imparted using laser-driven flyer plates. It has been shown that the order of sensitivity of charges to different shock regimes varies. In particular, ultrafine materials have been shown to relatively insensitive to long duration low pressure shocks and sensitive to short duration high pressure shocks. The materials that have been studied include HNS, RDX and PETN.

  13. A Taxonomy of Selected High School Equivalency Materials. Reading Science Materials. Supplementary Inventory.

    ERIC Educational Resources Information Center

    New York State Education Dept., Albany. Bureau of General Education Curriculum Development.

    Instructors can use this inventory to prepare high school equivalency students for the reading skills test of the new form of the Test of General Educational Development (GED). It replaces the instrument previously recommended for that purpose, the Iowa Tests of Educational Development (ITED). Fifty-two multiple choice questions test the ability…

  14. Material characteristics and equivalent circuit models of stacked graphene oxide for capacitive humidity sensors

    NASA Astrophysics Data System (ADS)

    Han, Kook In; Kim, Seung Du; Yang, Woo Seok; Kim, Hyeong Seok; Shin, Myunghun; Kim, Jong Pil; Lee, In Gyu; Cho, Byung Jin; Hwang, Wan Sik

    2016-03-01

    The oxidation properties of graphene oxide (GO) are systematically correlated with their chemical sensing properties. Based on an impedance analysis, the equivalent circuit models of the capacitive sensors are established, and it is demonstrated that capacitive operations are related to the degree of oxidation. This is also confirmed by X-ray diffraction and Raman analysis. Finally, highly sensitive stacked GO sensors are shown to detect humidity in capacitive mode, which can be useful in various applications requiring low power consumption.

  15. Material characteristics and equivalent circuit models of stacked graphene oxide for capacitive humidity sensors

    SciTech Connect

    Han, Kook In; Lee, In Gyu; Hwang, Wan Sik E-mail: whwang@kau.ac.kr; Kim, Seung Du; Yang, Woo Seok; Kim, Hyeong Seok; Shin, Myunghun E-mail: whwang@kau.ac.kr; Kim, Jong Pil; Cho, Byung Jin

    2016-03-15

    The oxidation properties of graphene oxide (GO) are systematically correlated with their chemical sensing properties. Based on an impedance analysis, the equivalent circuit models of the capacitive sensors are established, and it is demonstrated that capacitive operations are related to the degree of oxidation. This is also confirmed by X-ray diffraction and Raman analysis. Finally, highly sensitive stacked GO sensors are shown to detect humidity in capacitive mode, which can be useful in various applications requiring low power consumption.

  16. Tissue-equivalent materials for construction of tomographic dosimetry phantoms in pediatric radiology.

    PubMed

    Jones, A K; Hintenlang, D E; Bolch, W E

    2003-08-01

    Tissue equivalent materials have a variety of uses, including routine quality assurance and quality control in both diagnostic and therapeutic physics. They are frequently used in a research capacity to measure doses delivered to patients undergoing various therapeutic procedures. However, very few tissue equivalent materials have been developed for research use at the low photon energies encountered in diagnostic radiology. In this paper, we present a series of tissue-equivalent (TE) materials designed to radiographically mimic human tissue at diagnostic photon energies. These tissue equivalent materials include STES-NB (newborn soft tissue substitute), BTES-NB (newborn bone tissue substitute), LTES (newborn as well as a child/adult lung tissue substitute), STES (child/adult soft tissue substitute), and BTES (child/adult bone tissue substitute). In all cases, targeted reference elemental compositions are taken from those specified in the ORNL stylized computational model series. For each material, reference values of mass density, mass attenuation coefficients (10-150 keV), and mass energy-absorption coefficients (10-150 keV) were matched as closely as permitted by material selection and manufacturing constraints. Values of mu/rho and mu(en)/rho for the newborn TE materials are noted to have maximum deviations from their ORNL reference values of from 0 to -3% and from +2% to -3%, respectively, over the diagnostic energy range 10-150 keV. For the child/adult TE materials, these same maximal deviations of mu/rho and mu(en)/rho are from +1.5% to -3% and from +3% to -3%, respectively. Simple calculations of x-ray fluence attenuation under narrow-beam geometry using a 66 kVp spectrum typical of newborn CR radiographs indicate that the tissue-equivalent materials presented here yield estimates of absorbed dose at depth to within 3.6% for STES-NB, 3.2% for BTES-NB, and 1.2% for LTES of the doses assigned to reference newborn soft, bone, and lung tissue, respectively.

  17. [Development and equivalence evaluation of monosyllable lists of mandarin speech test materials].

    PubMed

    Zhang, Hua; Wang, Liang; Wang, Shuo; Chen, Jin; Chen, Ai-ting; Guo, Lian-sheng; Zhao, Xiao-yan; Ji, Chen

    2006-05-01

    To find a good speech material in audiology routine tests and cochlear implant evaluation, the monosyllable lists which were a part of mandarin speech test materials (MSTM) were edited and recorded. The equivalence test was done for all the lists. The professional group was set up at first, which composed of specialists of Chinese, mandarin teaching, linguistics and statistics. The principles of word selection were established according to the coherence with international speech test materials and mandarin. Ten Monosyllable lists, each of which has 50 mandarin words according to phonemic balance and criteria of speech audiometry, were edited. The balance was 3-dimension: vowels, consonants and four Chinese tones. One cassette was recorded by a male speaker (radiobroadcaster). The 72 normal hearing subjects were tested monaurally with ten monosyllable lists and the materials were presented by the earphone. The equivalence evaluation was done at the level of about 50% correct scores. Statistic analysis shows that 7 lists were equivalent in difficulty. They were ready for future research and clinical trial. The mandarin monosyllable lists were edited in terms of international standard and Chinese 3-dimension phonemic balance. Seven of them met the demands for research and clinical application.

  18. The modification of specific absorption rates in interstitial microwave hyperthermia via tissue-equivalent material bolus.

    PubMed

    Sundararaman, S; Denman, D L; Legorreta, R A; Foster, A E; Redmond, K P; Elson, H R; Born, A M; Samaratunga, R C; Lewis, G C; Kereiakes, J G

    1990-09-01

    Patterns of specific absorption rates generated by interstitial, microwave antenna arrays must be experimentally ascertained and quantified to facilitate their clinical incorporation. Phantom studies involved the use of four single-gap, coaxial antennas oriented in a 2 cm square array. These dipoles were driven in phase by a microwave generator at a frequency of 915 MHz. The inherent limitations in modifying the specific absorption rate patterns were addressed with the addition of bolus to the phantom. These additions of Guy's muscle tissue-equivalent material were made either proximal or distal to the phantom proper. Experiments conducted in the presence and absence of tissue-equivalent material bolus showed the ability to achieve broader bands of 50% power deposition in certain bolus conditions. These heating patterns were sufficiently reproducible and predictable to warrant clinical application of the bolus addition. A through-and-through method of catheter implantation allowed for bolus addition when deemed necessary. Treatments with veterinary and human patients using the bolus method to modify heating patterns yielded augmented patterns of power deposition. The effective length of the antennas that would radiate efficiently was essentially broadened via introduction of a microwave-interacting medium. As a result of the tissue equivalent material's ability to absorb microwave power, it was necessary to interpose minimally-interactive styrofoam spacers to limit heat transfer effects at the tissue-bolus interfaces.

  19. Evaluation of lead equivalence of patient and hardware materials in medical diagnostic x-ray shielding.

    PubMed

    Okunade, Akintunde Akangbe

    2005-02-01

    In the estimation of additional shielding requirements for primary beam apart from that provided by patient and hardware in the x-ray beam, there is the need to distinguish between attenuation and hardening properties of materials in comparison. In this work, numerical comparison of attenuation and hardening properties of phantom (Lucite, soft tissue, water) and hardware (aluminum and steel) materials with those of lead have been carried out. Results presented show that the shielding affordable by lead attenuation equivalent thicknesses (LAE) and lead hardening equivalent thicknesses (LHE) is not strictly equivalent to that affordable by thicknesses of substitutes (phantom materials, aluminum and steel) when there are differences in attenuation and hardening properties. Even though beams through LAE that are not "exact" have equal exposure values, the half value layers are higher than those through thicknesses of lead substitutes. Example calculations show that the use of lead thickness (LAE) that are not "exact" to account for the shielding afforded by the thickness of the patient (water phantom) produces lesser reduction of the primary radiation level in the area indicated for shielding. The "exact" LAE that will reduce the primary radiation level equally as the patient and radiographic table may be higher by close to 20% or more of that which is not "exact."

  20. Vector photochromism in polarization-sensitive materials.

    PubMed

    Chaganava, Irakli; Kakauridze, George; Kilosanidze, Barbara; Mshvenieradze, Yuri

    2014-07-01

    The phenomenon of vector photochromism was observed in some high-efficient polarization-sensitive materials depending on the radiant exposure of the inducing linearly polarized actinic light. The phenomenon has the purely vector nature because the absorption of the irradiated and unirradiated areas of the material is practically identical when we use unpolarized probing light. However, an essential change in the absorption spectrum was observed under probing the sample by linearly polarized nonactinic light when it passes through an analyzer, and this change depends on the value of radiant exposure. The kinetics of the photoanisotropy induced by linearly polarized actinic light at 457 nm was studied in case of wavelengths of 532 and 635 nm of the probing beam. The noticeable difference in absorbance was observed with increase in radiant exposure from 60  J/cm² up to 250  J/cm² for the used wavelengths of the probing beam. The experimental results obtained in polarization-sensitive material based on the ammonium salt of the azodye Mordant pure yellow in a gelatin matrix are presented. The dependence of the effective anisotropy on the material thickness has been investigated. The mechanism of the phenomenon is discussed. The observed effect can be used for creating dynamic polarization spectral filters controlled by light and the spectrally selective dynamic polarization holographic gratings.

  1. Spacecraft Charging Sensitivity to Material Properties

    NASA Technical Reports Server (NTRS)

    Minow, Joseph I.; Edwards, David L.

    2015-01-01

    Evaluating spacecraft charging behavior of a vehicle in the space environment requires knowledge of the material properties relevant to the charging process. Implementing surface and internal charging models requires a user to specify a number of material electrical properties including electrical resistivity parameters (dark and radiation induced), dielectric constant, secondary electron yields, photoemission yields, and breakdown strength in order to correctly evaluate the electric discharge threat posed by the increasing electric fields generated by the accumulating charge density. In addition, bulk material mass density and/or chemical composition must be known in order to analyze radiation shielding properties when evaluating internal charging. We will first describe the physics of spacecraft charging and show how uncertainties in material properties propagate through spacecraft charging algorithms to impact the results obtained from charging models. We then provide examples using spacecraft charging codes to demonstrate their sensitivity to material properties. The goal of this presentation is to emphasize the importance in having good information on relevant material properties in order to best characterize on orbit charging threats.

  2. Evaluation of two water-equivalent phantom materials for output calibration of photon and electron beams.

    PubMed

    Liu, Lizhong; Prasad, Satish C; Bassano, Daniel A

    2003-01-01

    Two commercially available water-equivalent solid phantom materials were evaluated for output calibration in both photon (6-15 MV) and electron (6-20 MeV) beams. The solid water 457 and virtual water materials have the same chemical composition but differ in manufacturing process and density. A Farmer-type ionization chamber was used for measuring the output of the photon beams at 5- and 10-cm depth and electron beams at maximum buildup depth in the solid phantoms and in natural water. The water-equivalency correction factor for the solid materials is defined as the ratio of the chamber reading in natural water to that in the solid at the same linear depth. For photon beams, the correction factor was found to be independent of depth and was 0.987 and 0.993 for 6- and 15-MV beams, respectively, for solid water. For virtual water, the corresponding correction factors were 0.993 and 0.998 for 6- and 15-MV beams, respectively. For electron beams, the correction factors ranged from 1.013 to 1.007 for energies of 6 to 20 MeV for both solid materials. This indicated that the water-equivalency of these materials is within +/- 1.3%, making them suitable substitutes for natural water in both photon and electron beam output measurements over a wide energy range. These correction factors are slightly larger than the manufacturers' advertised values (+/- 1.0% for solid water and +/- 0.5% for virtual water). We suggest that these corrections are large enough in most cases and should be applied in the calculation of beam outputs.

  3. Equivalent circuit for VO{sub 2} phase change material film in reconfigurable frequency selective surfaces

    SciTech Connect

    Sanphuang, Varittha; Ghalichechian, Nima; Nahar, Niru K.; Volakis, John L.

    2015-12-21

    We developed equivalent circuits of phase change materials based on vanadium dioxide (VO{sub 2}) thin films. These circuits are used to model VO{sub 2} thin films for reconfigurable frequency selective surfaces (FSSs). This is important as it provides a way for designing complex structures. A reconfigurable FSS filter using VO{sub 2} ON/OFF switches is designed demonstrating −60 dB isolation between the states. This filter is used to provide the transmission and reflection responses of the FSS in the frequency range of 0.1–0.6 THz. The comparison between equivalent circuit and full-wave simulation shows excellent agreement.

  4. Development of a new tissue-equivalent material applied to optimizing surgical accuracy.

    PubMed

    Jiang, Shan; Su, Zhiliang; Wang, Xingji; Liu, Sha; Yu, Yan

    2013-10-01

    The precision of orientation to target placement during invasive therapy is mainly influenced by tool-tissue interaction. In this study, we aim to investigate a transparent Poly (vinyl alcohol) (PVA) hydrogel as tissue-equivalent material which is used in accurate surgical insertion research. The PVA hydrogel with specified formula was prepared by means of physical and chemical crosslink. The effects of chemical composition and synthesis technique on the biomechanical property, density and micro-structure morphology of PVA materials have been investigated in detail. It can be concluded that when PVA concentration is 8 g/dl, the NaCl concentration is 4 wt.%, with mix water/DMSO solvent, prepared under 7 freeze/thaw cycles, the material has the most similar properties with kidney tissue. Experimental results demonstrate that this tissue-equivalent material could be used in the ex vivo insertion accuracy test for robot-assisted percutaneous intervention and surgical training in minimally invasive surgery (MIS). Copyright © 2013 Elsevier B.V. All rights reserved.

  5. SU-D-BRC-04: Development of Proton Tissue Equivalent Materials for Calibration and Dosimetry Studies

    SciTech Connect

    Olguin, E; Flampouri, S; Lipnharski, I; Bolch, W

    2016-06-15

    Purpose: To develop new proton tissue equivalent materials (PTEM), urethane and fiberglass based, for proton therapy calibration and dosimetry studies. Existing tissue equivalent plastics are applicable only for x-rays because they focus on matching mass attenuation coefficients. This study aims to create new plastics that match mass stopping powers for proton therapy applications instead. Methods: New PTEMs were constructed using urethane and fiberglass resin materials for soft, fat, bone, and lung tissue. The stoichiometric analysis method was first used to determine the elemental composition of each unknown constituent. New initial formulae were then developed for each of the 4 PTEMs using the new elemental compositions and various additives. Samples of each plastic were then created and exposed to a well defined proton beam at the UF Health Proton Therapy Institute (UFHPTI) to validate its mass stopping power. Results: The stoichiometric analysis method revealed the elemental composition of the 3 components used in creating the PTEMs. These urethane and fiberglass based resins were combined with additives such as calcium carbonate, aluminum hydroxide, and phenolic micro spheres to achieve the desired mass stopping powers and densities. Validation at the UFHPTI revealed adjustments had to be made to the formulae, but the plastics eventually had the desired properties after a few iterations. The mass stopping power, density, and Hounsfield Unit of each of the 4 PTEMs were within acceptable tolerances. Conclusion: Four proton tissue equivalent plastics were developed: soft, fat, bone, and lung tissue. These plastics match each of the corresponding tissue’s mass stopping power, density, and Hounsfield Unit, meaning they are truly tissue equivalent for proton therapy applications. They can now be used to calibrate proton therapy treatment planning systems, improve range uncertainties, validate proton therapy Monte Carlo simulations, and assess in-field and out

  6. Notch sensitivity of space shuttle tile materials

    NASA Technical Reports Server (NTRS)

    Newman, J. C., Jr.

    1980-01-01

    Tests were conducted at room temperature to determine the notch sensitivity of the thermal protection tile for the space shuttle. Two types of RSI tile were studied: LI-900 and LI-2200. Three point bend specimens were cut from discarded tiles in the in-plane (ip) and through-the-thickness (ttt) directions. They were tested with or without a sharp notch. The LI-900 (ip and ttt) specimens were not very notch sensitive, but the LI-2200 (ip and ttt) specimens were. The LI-2200 material showed about a 35 percent reduction in strength due to the presence of the notch. This reduction in strength should be considered in the design of mechanically fastened tile concepts.

  7. Water equivalent phantom materials for ¹⁹²Ir brachytherapy.

    PubMed

    Schoenfeld, Andreas A; Harder, Dietrich; Poppe, Björn; Chofor, Ndimofor

    2015-12-21

    Several solid phantom materials have been tested regarding their suitability as water substitutes for dosimetric measurements in brachytherapy with (192)Ir as a typical high energy photon emitter. The radial variations of the spectral photon fluence, of the total, primary and scattered photon fluence and of the absorbed dose to water in the transversal plane of the tested cylindrical phantoms surrounding a centric and coaxially arranged Varian GammaMed afterloading (192)Ir brachytherapy source were Monte-Carlo simulated in EGSnrc. The degree of water equivalence of a phantom material was evaluated by comparing the radial dose-to-water profile in the phantom material with that in water. The phantom size was varied over a large range since it influences the dose contribution by scattered photons with energies diminished by single and multiple Compton scattering. Phantom axis distances up to 10 cm were considered as clinically relevant. Scattered photons with energies reaching down into the 25 keV region dominate the photon fluence at source distances exceeding 3.5 cm. The tested phantom materials showed significant differences in the degree of water equivalence. In phantoms with radii up to 10 cm, RW1, RW3, Solid Water, HE Solid Water, Virtual Water, Plastic Water DT, and Plastic Water LR phantoms show excellent water equivalence with dose deviations from a water phantom not exceeding 0.8%, while Original Plastic Water (as of 2015), Plastic Water (1995), Blue Water, polyethylene, and polystyrene show deviations up to 2.6%. For larger phantom radii up to 30 cm, the deviations for RW1, RW3, Solid Water, HE Solid Water, Virtual Water, Plastic Water DT, and Plastic Water LR remain below 1.4%, while Original Plastic Water (as of 2015), Plastic Water (1995), Blue Water, polyethylene, and polystyrene produce deviations up to 8.1%. PMMA plays a separate role, with deviations up to 4.3% for radii not exceeding 10 cm, but below 1% for radii up to 30 cm. As

  8. Measuring Child Poverty in South Africa: Sensitivity to the Choice of Equivalence Scale and an Updated Profile

    ERIC Educational Resources Information Center

    Streak, Judith Christine; Yu, Derek; Van der Berg, Servaas

    2009-01-01

    This paper offers evidence on the sensitivity of child poverty in South Africa to changes in the adult equivalence scale (AES) and updates the child poverty profile based on the Income and Expenditure Survey 2005/06. Setting the poverty line at the 40th percentile of households calculated with different AESs the scope and composition of child…

  9. Measuring Child Poverty in South Africa: Sensitivity to the Choice of Equivalence Scale and an Updated Profile

    ERIC Educational Resources Information Center

    Streak, Judith Christine; Yu, Derek; Van der Berg, Servaas

    2009-01-01

    This paper offers evidence on the sensitivity of child poverty in South Africa to changes in the adult equivalence scale (AES) and updates the child poverty profile based on the Income and Expenditure Survey 2005/06. Setting the poverty line at the 40th percentile of households calculated with different AESs the scope and composition of child…

  10. Field-Sensitive Materials for Optical Applications

    NASA Technical Reports Server (NTRS)

    Choi, Sang H.; Little, Mark

    2002-01-01

    The purpose of investigation is to develop the fundamental materials and fabrication technology for field-controlled spectrally active optics that are essential for industry, NASA, and DOD (Department of Defense) applications such as: membrane optics, filters for LIDARs (Light Detection and Ranging), windows for sensors and probes, telescopes, spectroscopes, cameras, light valves, light switches, flat-panel displays, etc. The proposed idea is based on the quantum-dots (QD) array or thin-film of field-sensitive Stark and Zeeman materials and the bound excitonic state of organic crystals that will offer optical adaptability and reconfigurability. Major tasks are the development of concept demonstration article and test data of field-controlled spectrally smart active optics (FCSAO) for optical multi-functional capabilities on a selected spectral range.

  11. SU-E-T-388: Evaluation of Electronic Brachytherapy Dose Distributions in Tissue Equivalent Materials

    SciTech Connect

    Johnson, M; Ahmad, S; Johnson, D

    2015-06-15

    Purpose: To study the measured and calculated dose distributions for electronic brachytherapy (EBT) in various tissue equivalent homogenous materials. Methods: Calculated dose distributions in water were generated using published TG-43 parameters in Varian BrachyVision software for a 50 kVp, 50 cm Xoft source. Dose distributions were measured within a 3D-scanning tank using dosimeters including: PTW 0.125 cc, pin-point, and parallel-plate ion chambers, Sun Nuclear “Edge” diode and Gafchromic EBT3 film. Multi-channel film dosimetry was used in film analysis. EBT3 film curves were calibrated via radial dose comparison to both independently measured and published data. The resulting film calibration was utilized to measure dose distributions created by titanium filtered source utilized in clinical brachytherapy applications. Data was collected within homogenous PMMA, vinyl, polystyrene, paraffin, and water-equivalent plastic phantoms. Results: Ion-chamber data was corrected to effective points of measurement and normalized prior to comparison between calculated and measured dose distributions. Measurements made in water and water equivalent materials compared well with results from treatment planning software. The maximum percent differences (relative to water) observed between 1 cm and 3.5 cm depth from source for each of the phantom materials are as follows: PMMA 35%, polystyrene 41%, plastic-water 23%, vinyl 115%, and paraffin 46%. Conclusion: The increased probability of photoelectric interactions occurring within the patient during electronic brachytherapy will emphasize the radiological differences between varying human tissues in dose deposition. These differences can Result in clinically significant dose perturbations and it is therefore recommended to move to a model based dose calculation, as outlined in TG-186, to improve the dosimetric accuracy of low energy EBT.

  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

    2016-09-07

    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. [Development and equivalence evaluation of spondee lists of mandarin speech test materials].

    PubMed

    Zhang, Hua; Wang, Shuo; Wang, Liang; Chen, Jing; Chen, Ai-ting; Guo, Lian-sheng; Zhao, Xiao-yan; Ji, Chen

    2006-06-01

    To edit the spondee (disyllable) word lists as a part of mandarin speech test materials (MSTM). These will be basic speech materials for routine tests in clinics and laboratories. Two groups of professionals (audiologists, Chinese and Mandarin scientists, linguistician and statistician) were set up at first. The editing principles were established after 3 round table meetings. Ten spondee lists, each with 50 words, were edited and recorded into cassettes. All lists were phonemically balanced (3-dimensions: vowels, consonants and Chinese tones). Seventy-three normal hearing college students were tested. The speech was presented by earphone monaurally. Three statistic methods were used for equivalent analysis. Related analysis showed that all lists were much related, except List 5. Cluster analysis showed that all ten lists could be classified as two groups. But Kappa test showed that the lists' homogeneity were not well. Spondee lists are one of the most routine speech test materials. Their editing, recording and equivalent evaluation are affected by many factors. This also needs multi-discipline cooperation. All lists edited in present study need future modification in recording and testing in order to be used clinically and in research. The phonemic balance should be kept.

  14. 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.

  15. Calibration procedure for focal plane array cameras and noise equivalent material loss for quantitative thermographic NDT

    SciTech Connect

    Marinetti, S.; Maldague, X.; Prystay, M.

    1997-03-01

    In this paper, a complete procedure is proposed for the calibration of a focal plane array in quantitative infrared nondestructive testing (NDT). This procedure includes vignetting correction and gray level conversion into temperature. A noise analysis is also presented in the context of pulsed infrared thermography applied to NDT. In this analysis, the authors introduce a new parameter, the noise equivalent material loss (NEML). The NEML is a global figure of merit which allows the comparison of different experimental set-ups for infrared pulsed thermography. Theory, experimental validation of the proposed concepts, and comparison with a few infrared scanning thermal imagers are presented as well.

  16. Modelling parallel assemblies of porous materials using the equivalent circuit method.

    PubMed

    Pieren, Reto; Heutschi, Kurt

    2015-02-01

    Recently, the accuracy of the parallel transfer matrix method (P-TMM) and the admittance sum method (ASM) in the prediction of the absorption properties of parallel assemblies of materials was investigated [Verdière, Panneton, Elkoun, Dupont, and Leclaire, J. Acoust. Soc. Am. 136, EL90-EL95 (2014)]. It was demonstrated that P-TMM is more versatile than ASM, as a larger variety of different backing configurations can be handled. Here it will be shown that the same universality is offered by the equivalent circuit method.

  17. High sensitive materials in medical holographic microscopy

    NASA Astrophysics Data System (ADS)

    Osanlou, A.; Snashall, E.; Osanlou, O.; Osanlou, R.; Mirlis, E.; Shi, Lishen; Bjelkhagen, H.

    2015-02-01

    High sensitivity is defined in relation to the energy required to perform holographic recording. High sensitivity in silver halide materials is their main advantage over other similarly high resolving power holographic recording materials. This work reports progress on the development of silver halide based 'true colour holographic imaging', under a microscope. A thin layer of ultrafine grains of silver halide crystals of around 10 nm average diameter, dispersed in a colloid and coated on a substrate is used as the recording media. The significance of this method so far, is in its ability to produce 'true colour' three-dimensional images of specimen. The recordings have an appreciable depth, permitting the observer to scan through the image under a microscope, as one might with a real specimen sample. Current methods could perform ' True colour holographic imaging' directly under a microscope. The recording methodology has the potential for deeper complex and scattering media imaging, using very small pulses of appropriate laser wavelengths. The methodology, using novel nanosize panchromatic recording media consisting of dispersed fine nano grain crystals, could potentially revolutionise related medical imaging techniques. Future development of digital media will allow it to be utilized in this manner.

  18. Effects of selected materials and geometries on the beta dose equivalent rate in a tissue equivalent phantom immersed in infinite clouds of 133Xe.

    PubMed

    Piltingsrud, H V; Gels, G L

    1986-06-01

    Most calculations of dose equivalent (D.E.) rates at 70-micron tissue depths in tissue equivalent (T.E.) phantoms from infinite clouds (radius exceeds maximum beta range in air) of 133Xe do not consider the possible effects of clothing overlays. Consequently, a series of measurements were made using a 1-mm-thick plastic scintillation detector assembly mounted in a tissue equivalent (T.E.) phantom with an overlay of 70 micron of T.E. material. This assembly was placed in an infinite cloud containing a known concentration of 133Xe. Material samples were placed at selected distances from the detector phantom, both individually and in various combinations. Pulse-height spectra resulting from beta radiations were converted to relative D.E. rates at a 70-micron tissue depth. The relative D.E. rates were reduced from values with no clothing cover by as little as 45% when placing a single thin nylon cloth 1 cm from the phantom, to 94% for a T-shirt material plus wool material plus denim placed 1/2, 1 and 3 cm, respectively, from the phantom. The results indicate that even loosely fitting clothing can have an important effect on reducing the D.E. rate. Close-fitting clothing appears to provide better protection.

  19. Effects of selected materials and geometries on the beta dose equivalent rate in a tissue equivalent phantom immersed in infinite clouds of 133Xe

    SciTech Connect

    Piltingsrud, H.V.; Gels, G.L.

    1986-06-01

    Most calculations of dose equivalent (D.E.) rates at 70-micron tissue depths in tissue equivalent (T.E.) phantoms from infinite clouds (radius exceeds maximum beta range in air) of /sup 133/Xe do not consider the possible effects of clothing overlays. Consequently, a series of measurements were made using a 1-mm-thick plastic scintillation detector assembly mounted in a tissue equivalent (T.E.) phantom with an overlay of 70 micron of T.E. material. This assembly was placed in an infinite cloud containing a known concentration of /sup 133/Xe. Material samples were placed at selected distances from the detector phantom, both individually and in various combinations. Pulse-height spectra resulting from beta radiations were converted to relative D.E. rates at a 70-micron tissue depth. The relative D.E. rates were reduced from values with no clothing cover by as little as 45% when placing a single thin nylon cloth 1 cm from the phantom, to 94% for a T-shirt material plus wool material plus denim placed 1/2, 1 and 3 cm, respectively, from the phantom. The results indicate that even loosely fitting clothing can have an important effect on reducing the D.E. rate. Close-fitting clothing appears to provide better protection.

  20. SU-E-T-424: Feasibility of 3D Printed Radiological Equivalent Customizable Tissue Like Materials

    SciTech Connect

    Johnson, D; Ferreira, C; Ahmad, S

    2015-06-15

    Purpose: To investigate the feasibility of 3D printing CT# specific radiological equivalent tissue like materials. Methods: A desktop 3D printer was utilized to create a series of 3 cm x 3 cm x 2 cm PLA plastic blocks of varying fill densities. The fill pattern was selected to be hexagonal (Figure 1). A series of blocks was filled with paraffin and compared to a series filled with air. The blocks were evaluated with a “GE Lightspeed” 16 slice CT scanner and average CT# of the centers of the materials was determined. The attenuation properties of the subsequent blocks were also evaluated through their isocentric irradiation via “TrueBeam” accelerator under six beam energies. Blocks were placed upon plastic-water slabs of 4 cm in thickness assuring electronic equilibrium and data was collected via Sun Nuclear “Edge” diode detector. Relative changes in dose were compared with those predicted by Varian “Eclipse” TPS. Results: The CT# of 3D printed blocks was found to be a controllable variable. The fill material was able to narrow the range of variability in each sample. The attenuation of the block tracked with the density of the total fill structure. Assigned CT values in the TPS were seen to fall within an expected range predicted by the CT scans of the 3D printed blocks. Conclusion: We have demonstrated that it is possible to 3D print materials of varying tissue equivalencies, and that these materials have radiological properties that are customizable and predictable.

  1. Water equivalence of various materials for clinical proton dosimetry by experiment and Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Al-Sulaiti, Leena; Shipley, David; Thomas, Russell; Kacperek, Andrzej; Regan, Patrick; Palmans, Hugo

    2010-07-01

    The accurate conversion of dose to various materials used in clinical proton dosimetry to dose-to-water is based on fluence correction factors, accounting for attenuation of primary protons and production of secondary particles due to non-elastic nuclear interactions. This work aims to investigate the depth dose distribution and the fluence correction with respect to water or graphite at water equivalent depths (WED) in different target materials relevant for dosimetry such as polymethyl methacrylate (PMMA), graphite, A-150, aluminium and copper at 60 and 200 MeV. This was done through a comparison between Monte Carlo simulation using MCNPX 2.5.0, analytical model calculations and experimental measurements at Clatterbridge Centre of Oncology (CCO) in a 60 MeV modulated and un-modulated proton beam. MCNPX simulations indicated small fluence corrections for all materials with respect to graphite and water in 60 and 200 MeV except for aluminium. The analytical calculations showed an increase in the fluence correction factor to a few percent for all materials with respect to water at 200 MeV. The experimental measurements for 60 MeV un-modulated beam indicated a good agreement with MCNPX. For the modulated beam the fluence correction factor was found to be decreasing below unity by up to few percent with depth for aluminium and copper but almost constant and unity for A-150.

  2. Evaluation of parameter sensitivities for flux-switching permanent magnet machines based on simplified equivalent magnetic circuit

    NASA Astrophysics Data System (ADS)

    Zhang, Gan; Hua, Wei; Cheng, Ming

    2017-05-01

    Most of the published papers regarding the design of flux-switching permanent magnet machines are focused on the analysis and optimization of electromagnetic or mechanical behaviors, however, the evaluate of the parameter sensitivities have not been covered, which contrarily, is the main contribution of this paper. Based on the finite element analysis (FEA) and simplified equivalent magnetic circuit, the method proposed in this paper enables the influences of parameters on the electromagnetic performances, i.e. the parameter sensitivities, to be given by equations. The FEA results are also validated by experimental measurements.

  3. Nuclear reaction measurements on tissue-equivalent materials and GEANT4 Monte Carlo simulations for hadrontherapy

    NASA Astrophysics Data System (ADS)

    De Napoli, M.; Romano, F.; D'Urso, D.; Licciardello, T.; Agodi, C.; Candiano, G.; Cappuzzello, F.; Cirrone, G. A. P.; Cuttone, G.; Musumarra, A.; Pandola, L.; Scuderi, V.

    2014-12-01

    When a carbon beam interacts with human tissues, many secondary fragments are produced into the tumor region and the surrounding healthy tissues. Therefore, in hadrontherapy precise dose calculations require Monte Carlo tools equipped with complex nuclear reaction models. To get realistic predictions, however, simulation codes must be validated against experimental results; the wider the dataset is, the more the models are finely tuned. Since no fragmentation data for tissue-equivalent materials at Fermi energies are available in literature, we measured secondary fragments produced by the interaction of a 55.6 MeV u-1 12C beam with thick muscle and cortical bone targets. Three reaction models used by the Geant4 Monte Carlo code, the Binary Light Ions Cascade, the Quantum Molecular Dynamic and the Liege Intranuclear Cascade, have been benchmarked against the collected data. In this work we present the experimental results and we discuss the predictive power of the above mentioned models.

  4. Nuclear reaction measurements on tissue-equivalent materials and GEANT4 Monte Carlo simulations for hadrontherapy.

    PubMed

    De Napoli, M; Romano, F; D'Urso, D; Licciardello, T; Agodi, C; Candiano, G; Cappuzzello, F; Cirrone, G A P; Cuttone, G; Musumarra, A; Pandola, L; Scuderi, V

    2014-12-21

    When a carbon beam interacts with human tissues, many secondary fragments are produced into the tumor region and the surrounding healthy tissues. Therefore, in hadrontherapy precise dose calculations require Monte Carlo tools equipped with complex nuclear reaction models. To get realistic predictions, however, simulation codes must be validated against experimental results; the wider the dataset is, the more the models are finely tuned.Since no fragmentation data for tissue-equivalent materials at Fermi energies are available in literature, we measured secondary fragments produced by the interaction of a 55.6 MeV u(-1) (12)C beam with thick muscle and cortical bone targets. Three reaction models used by the Geant4 Monte Carlo code, the Binary Light Ions Cascade, the Quantum Molecular Dynamic and the Liege Intranuclear Cascade, have been benchmarked against the collected data. In this work we present the experimental results and we discuss the predictive power of the above mentioned models.

  5. To probe the equivalence and opulence of nanocrystal and nanotube based dye-sensitized solar cells

    SciTech Connect

    Jyoti, Divya; Mohan, Devendra

    2016-05-06

    Dye-Sensitized solar cells based on TiO{sub 2} nanocrystal and TiO{sub 2} nanotubes have been fabricated by a simple sol-gel hydrothermal process and their performances have been compared. Current density and voltage (JV) characteristics and incident photon to current conversion efficiency (IPCE) plots have been set as criterion to check which one is better as a photoanode candidate in dye-sensitized solar cell. It has been observed that although open circuit voltage values for both type of cells do not differ much still, nanotube based dye-sensitized solar cells are more successful having an efficiency value of 7.28%.

  6. Water equivalent thickness values of materials used in beams of protons, helium, carbon and iron ions

    PubMed Central

    Zhang, Rui; Taddei, Phillip J; Fitzek, Markus M; Newhauser, Wayne D

    2010-01-01

    Heavy charged particle beam radiotherapy for cancer is of increasing interest because it delivers a highly conformal radiation dose to the target volume. Accurate knowledge of the range of a heavy charged particle beam after it penetrates a patient’s body or other materials in the beam line is very important and is usually stated in terms of the water equivalent thickness (WET). However, methods of calculating WET for heavy charged particle beams are lacking. Our objective was to test several simple analytical formulas previously developed for proton beams for their ability to calculate WET values for materials exposed to beams of protons, helium, carbon and iron ions. Experimentally measured heavy charged particle beam ranges and WET values from an iterative numerical method were compared with the WET values calculated by the analytical formulas. Inmost cases, the deviations were within 1 mm. We conclude that the analytical formulas originally developed for proton beams can also be used to calculate WET values for helium, carbon and iron ion beams with good accuracy. PMID:20371908

  7. Water equivalent thickness values of materials used in beams of protons, helium, carbon and iron ions.

    PubMed

    Zhang, Rui; Taddei, Phillip J; Fitzek, Markus M; Newhauser, Wayne D

    2010-05-07

    Heavy charged particle beam radiotherapy for cancer is of increasing interest because it delivers a highly conformal radiation dose to the target volume. Accurate knowledge of the range of a heavy charged particle beam after it penetrates a patient's body or other materials in the beam line is very important and is usually stated in terms of the water equivalent thickness (WET). However, methods of calculating WET for heavy charged particle beams are lacking. Our objective was to test several simple analytical formulas previously developed for proton beams for their ability to calculate WET values for materials exposed to beams of protons, helium, carbon and iron ions. Experimentally measured heavy charged particle beam ranges and WET values from an iterative numerical method were compared with the WET values calculated by the analytical formulas. In most cases, the deviations were within 1 mm. We conclude that the analytical formulas originally developed for proton beams can also be used to calculate WET values for helium, carbon and iron ion beams with good accuracy.

  8. A sensitivity analysis of the modified chi-square ratio statistic for equivalence testing of aerodynamic particle size distribution.

    PubMed

    Weber, Benjamin; Lee, Sau L; Lionberger, Robert; Li, Bing V; Tsong, Yi; Hochhaus, Guenther

    2013-04-01

    Demonstration of equivalence in aerodynamic particle size distribution (APSD) is one key component for establishing bioequivalence of orally inhaled drug products. We previously proposed a modified version of the Chi-square ratio statistic (mCSRS) for APSD equivalence testing and demonstrated that the median of the distribution of the mCSRS (MmCSRS) is a robust metric when test (T) and reference (R) cascade impactor (CI) profiles are identical. Here, we systematically evaluate the behavior of the MmCSRS when T and R CI profiles differ from each other in their mean deposition and variability on a single and multiple sites. All CI profiles were generated by Monte-Carlo simulations based upon modified actual CI data. Twenty thousand sets of 30 T and 30 R CI profiles were simulated for each scenario, and the behavior of the MmCSRS was correlated to metrics that characterize the difference between T and R product in mean deposition and variability. The two key findings were, first, that the MmCSRS is more sensitive to difference between T and R CI profiles on high deposition sites, and second, that a cut-off value for APSD equivalence testing based on the MmCSRS needs to be scaled on the variability of the R product. The former is considered as beneficial for equivalence testing of CI profiles as it decreases the likelihood of failing identical CI profiles by chance, in part, due to increasing analytical variability associated with lower deposition sites. The latter is expected to be important for consistently being able to discriminate equivalent from inequivalent CI profiles.

  9. Accuracy of the domain method for the material derivative approach to shape design sensitivities

    NASA Technical Reports Server (NTRS)

    Yang, R. J.; Botkin, M. E.

    1987-01-01

    Numerical accuracy for the boundary and domain methods of the material derivative approach to shape design sensitivities is investigated through the use of mesh refinement. The results show that the domain method is generally more accurate than the boundary method, using the finite element technique. It is also shown that the domain method is equivalent, under certain assumptions, to the implicit differentiation approach not only theoretically but also numerically.

  10. MO-F-CAMPUS-I-03: Tissue Equivalent Material Phantom to Test and Optimize Coherent Scatter Imaging for Tumor Classification

    SciTech Connect

    Albanese, K; Morris, R; Lakshmanan, M; Greenberg, J; Kapadia, A

    2015-06-15

    Purpose: To accurately model different breast geometries using a tissue equivalent phantom, and to classify these tissues in a coherent x-ray scatter imaging system. Methods: A breast phantom has been designed to assess the capability of coded aperture coherent x-ray scatter imaging system to classify different types of breast tissue (adipose, fibroglandular, tumor). The tissue-equivalent phantom was modeled as a hollow plastic cylinder containing multiple cylindrical and spherical inserts that can be positioned, rearranged, or removed to model different breast geometries. Each enclosure can be filled with a tissue-equivalent material and excised human tumors. In this study, beef and lard, placed inside 2-mm diameter plastic Nalgene containers, were used as surrogates for fibroglandular and adipose tissue, respectively. The phantom was imaged at 125 kVp, 40 mA for 10 seconds each with a 1-mm pencil beam. The raw data were reconstructed using a model-based reconstruction algorithm and yielded the location and form factor, or momentum transfer (q) spectrum of the materials that were imaged. The measured material form factors were then compared to the ground truth measurements acquired by x-ray diffraction (XRD) imaging. Results: The tissue equivalent phantom was found to accurately model different types of breast tissue by qualitatively comparing our measured form factors to those of adipose and fibroglandular tissue from literature. Our imaging system has been able to define the location and composition of the various materials in the phantom. Conclusion: This work introduces a new tissue equivalent phantom for testing and optimization of our coherent scatter imaging system for material classification. In future studies, the phantom will enable the use of a variety of materials including excised human tissue specimens in evaluating and optimizing our imaging system using pencil- and fan-beam geometries. United States Department of Homeland Security Duke University

  11. Measurements of radioactivity in Jamaican building materials and gamma dose equivalents in a prototype red mud house

    SciTech Connect

    Pinnock, W.R. )

    1991-11-01

    Concentrations of 226Ra, 232Th, and 40K measured in bauxite waste, local building materials, and soils are presented and used in model equations to estimate the effective gamma dose-equivalent increments over background in the center of a standard-sized room in a prototype house. Calculated and measured values compare reasonably well.

  12. On equivalence of discrete-discrete and continuum-discrete design sensitivity analysis

    NASA Technical Reports Server (NTRS)

    Choi, Kyung K.; Twu, Sung-Ling

    1989-01-01

    Developments in design sensitivity analysis (DSA) method have been made using two fundamentally different approaches as shown. In the first approach, a discretized structural finite element model is used to carry out DSA. There are three different methods in the discrete DSA approach: finite difference, semi-analytical, and analytical methods. The finite difference method is a popular one due to its simplicity, but a serious shortcoming of the method is the uncertainty in the choice of a perturbation step size of design variables. In the semi-analytical method, the derivatives of stiffness matrix is computed by finite differences, whereas in the analytical method, the derivatives are obtained analytically. For the shape design variable, computation of analytical derivative of stiffness matrix is quite costly. Because of this, the semi-analytical method is a popular choice in discrete shape DSA approach. However, recently, Barthelemy and Haftka presented that the semi-analytical method can have serious accuracy problems for shape design variables in structures modeled by beam, plate, truss, frame, and solid elements. They found that accuracy problems occur even for a simple cantilever beam. In the second approach, a continuum model of the structure is used to carry out DSA.

  13. Simplified microsatellite instability detection protocol provides equivalent sensitivity to robust detection strategies in Lynch syndrome patients

    PubMed Central

    Babaei, Hadi; Zeinalian, Mehrdad; Emami, Mohammad Hassan; Hashemzadeh, Mortaza; Farahani, Najmeh; Salehi, Rasoul

    2017-01-01

    Objective : Germline mutations in mismatch repair (MMR) genes cause Lynch syndrome (LS). LS is an inherited disease, and an important consequence of MMR deficiency is microsatellite instability (MSI) phenotype. MSI phenotype influences the efficacy of 5 fluorouracil (5-FU) chemotherapy. Reproducible, cost effective, and easy to perform laboratory tests are required to include MSI detection in routine laboratory practice. Evaluation of CAT25 as monomorphic short tandem repeat sequence enables CAT25 to be an efficient screening tool among hereditary nonpolyposis colorectal cancer (HNPCC) patients compared with other methods used currently. Methods : Based on Amsterdam II criteria, 31 patients in 31 families were shortlisted from a total number of 1,659 colorectal cancer patients. MSI status was examined in these patients using CAT25 and a commercially available Promega MSI five-marker-based detection system as well as immunohistochemical (IHC) staining of four important MMR proteins. Patients were scored as high microsatellite instable (MSI-H), low (MSI-L), or stable (MSS). MSI status determined by CAT25 single mononucleotide marker was compared with that of five mononucleotide markers, Promega commercial kit, and IHC method. Results : MMR protein deficiency was observed on 7/31 probands using IHC methodology and 6/31 categorized as MSI-H using commercial kit or CAT25 single marker. The sensitivity and specificity of the CAT25 single marker were the same as those detected by five-marker Promega commercial kit in our patients. Conclusions : Based on our results, the performance of the CAT25 single mononucleotide marker for MSI status determination in our HNPCC patients is the same as that of the five-marker-based commercial kit. PMID:28607805

  14. Dual energy CT-based characterization of x-ray attenuation properties of breast equivalent material plates

    NASA Astrophysics Data System (ADS)

    Geeraert, N.; Klausz, R.; Giudici, P.; Muller, S.; Cockmartin, L.; Bosmans, H.

    2012-03-01

    Breast density is more and more considered as an important risk factor for breast cancer and several quantitative breast density evaluation methods have been proposed. The reference material for simulation of the breast attenuation properties of glandular and adipose breast tissues is manufactured by a single provider. In order to characterize the attenuation properties of these materials, measurements in Hounsfield Units (HU) have been performed using a CT-scanner. Breastequivalent plates have been imaged in different configurations (plates in and orthogonal to image planes), providing consistent results (+/- 1.3 HU). Breast density equivalent plates of different nominal breast density equivalences and sizes were measured, demonstrating both a good homogeneity within the plates (+/- 1.8 HU) and a good consistency between plates of the same nominal breast density equivalence (+/- 1.5 HU). In addition, dual energy CT provided mono-energetic HU from which mono-energetic linear attenuation coefficients of water and glandular and adipose equivalent materials were computed. The values for these coefficients were found in good agreement with results from literature, respectively direct mono-energetic measurements of breast samples, and computation by combining published breast tissue atomic compositions and linear attenuation coefficient tables. In conclusion, CT was found effective for the verification of the breast equivalent material, and the homogeneity and consistency of the plates were found satisfactory. Furthermore, the most recent spectral CT technology allowed demonstrating a good agreement of the attenuation properties of breastequivalent material plates with state-of-the-art knowledge of real breast tissue attenuation.

  15. Sensitivity of nucleon-nucleus scattering to the off-shell behavior of on-shell equivalent {ital NN} potentials

    SciTech Connect

    Arellano, H.F.; Brieva, F.A.; Sander, M.; von Geramb, H.V. |

    1996-11-01

    The sensitivity of nucleon-nucleus elastic scattering to the off-shell behavior of realistic nucleon-nucleon interactions is investigated when on-shell equivalent nucleon-nucleon potentials are used. The study is based on applications of the full-folding optical model potential for an explicit treatment of the off-shell behavior of the nucleon-nucleon effective interaction. Applications were made at beam energies between 40 and 500 MeV for proton scattering from {sup 40}Ca and {sup 208}Pb. We use the momentum-dependent Paris potential and its local on-shell equivalent as obtained with the Gelfand-Levitan and Marchenko inversion formalism for the two nucleon Schr{umlt o}dinger equation. Full-folding calculations for nucleon-nucleus scattering show moderate fluctuations in the corresponding observables. This sets narrow margins within which off-shell features of the nucleon-nucleon interaction can be resolved. Based on these results, inversion potentials were also constructed directly from phenomenological phase shifts (SM94). Their use in nucleon-nucleus scattering at intermediate energies provides an improved description of the data relative to those obtained from current realistic potential models. {copyright} {ital 1996 The American Physical Society.}

  16. Measuring PET scanner sensitivity; Relating count rates to image signal-to-noise ratios using noise equivalent counts

    SciTech Connect

    Strother, S.C. ); Casey, M.E. ); Hoffman, E.J. . Nuclear Medicine Lab.)

    1990-04-01

    Sensitivity parameters derived from a plot of a scanner's true coincidence count (TCC) rates as a function of activity in a 20 cm cylindrical phantom have no direct link to image quality. Noise equivalent count (NEC) rate curves, which incorporate the noise effects of subtracting the randoms and scatter count components provide a direct link between image signal-to-noise ratios and the scatter, randoms and trues coincidence count rates. The authors have measured TCC and NEC curves with a standardized 20 cm diameter nylon cylinder for five different PET scanners with several scanner-collimator combinations. In addition, the authors have compared TCC and NEC curves on one scanner with those from an Alderson brain phantom.

  17. Using the Stimulus Equivalence Paradigm to Teach Course Material in an Undergraduate Rehabilitation Course

    ERIC Educational Resources Information Center

    Walker, Brooke D.; Rehfeldt, Ruth Anne; Ninness, Chris

    2010-01-01

    In 2 experiments, we examined whether the stimulus equivalence instructional paradigm could be used to teach relations among names, definitions, causes, and common treatments for disabilities using a selection-based intraverbal training format. Participants were pre- and posttested on vocal intraverbal relations and were trained using…

  18. Using the Stimulus Equivalence Paradigm to Teach Course Material in an Undergraduate Rehabilitation Course

    ERIC Educational Resources Information Center

    Walker, Brooke D.; Rehfeldt, Ruth Anne; Ninness, Chris

    2010-01-01

    In 2 experiments, we examined whether the stimulus equivalence instructional paradigm could be used to teach relations among names, definitions, causes, and common treatments for disabilities using a selection-based intraverbal training format. Participants were pre- and posttested on vocal intraverbal relations and were trained using…

  19. Photoneutron depth dose equivalent distributions in high-energy X-ray medical accelerators by a novel position-sensitive dosimeter.

    PubMed

    Hakimi, Amir; Sohrabi, Mehdi

    2017-04-01

    The purpose of this study was to; (1) investigate employing a novel position-sensitive mega-size polycarbonate (MSPC) dosimeter for photoneutron (PN) depth, profile and dose equivalent distributions studies in a multilayer polyethylene phantom in a Siemens ONCOR accelerator, and (2) develop depth dose equivalent distribution matrix data at different depths and positions of the phantom for patient PN dose equivalent determination and in particular for PN secondary cancer risk estimation. Position-sensitive MSPC dosimeters were successfully exposed at 9 different depths of the phantom in a 10×10cm(2) X-ray field. The dosimeters were processed in mega-size electrochemical chambers at optimum conditions. Each MSPC dosimeter was placed at a known phantom depth for PN depth dose equivalents and profiles on transverse, longitudinal and diagonal axes and isodose equivalent distribution studies in and out of the X-ray beam. PN dose equivalent distributions at any depth showed the highest value at the beam central axis and decreases as the distance increases. PN dose equivalent at any position studied in the axes has a maximum value on the phantom surface which decreases as depth increases due to flux reduction by multi-elastic scattering interactions. Extensive PN dose equivalent matrix data at different depths and positions in the phantom were determined. The position-sensitive MSPC dosimeters proved to be highly efficient for PN depth, profile and isodose equivalent distribution studies. The extensive data obtained highly assists for determining PN dose equivalent of a patient undergoing high-energy X-ray therapy and for PN secondary cancer risk estimation. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  20. Whispering gallery mode resonators based on radiation-sensitive materials

    NASA Technical Reports Server (NTRS)

    Savchenkov, Anatoliy (Inventor); Maleki, Lutfollah (Inventor); Ilchenko, Vladimir (Inventor); Handley, Timothy A. (Inventor)

    2005-01-01

    Whispering gallery mode (WGM) optical resonators formed of radiation-sensitive materials to allow for permanent tuning of their resonance frequencies in a controlled manner. Two WGM resonators may be cascaded to form a composite filter to produce a second order filter function where at least one WGM resonator is formed a radiation-sensitive material to allow for proper control in the overlap of the two filter functions.

  1. Equivalent material modelling of sandwich beams, evanescent solutions and damping investigations

    NASA Astrophysics Data System (ADS)

    de Rijk, Sophie; Nijman, Eugene

    2016-11-01

    A novel method for representing the transverse vibrations of sandwich beams as equivalent Timoshenko beams is developed. Special attention is given to damping modelling together with the evanescent parts of the solutions to assert applicability of the approach to any boundary conditions. Shear stiffness is evaluated based on current knowledge. The latter is then used to update the reference theory for vibrations in sandwich beams. Analytical case studies are presented to show the performance and limitations of the method and compared with experimental data.

  2. Energy absorption buildup factors, exposure buildup factors and Kerma for optically stimulated luminescence materials and their tissue equivalence for radiation dosimetry

    NASA Astrophysics Data System (ADS)

    Singh, Vishwanath P.; Badiger, N. M.

    2014-11-01

    Optically stimulated luminescence (OSL) materials are sensitive dosimetric materials used for precise and accurate dose measurement for low-energy ionizing radiation. Low dose measurement capability with improved sensitivity makes these dosimeters very useful for diagnostic imaging, personnel monitoring and environmental radiation dosimetry. Gamma ray energy absorption buildup factors and exposure build factors were computed for OSL materials using the five-parameter Geometric Progression (G-P) fitting method in the energy range 0.015-15 MeV for penetration depths up to 40 mean free path. The computed energy absorption buildup factor and exposure buildup factor values were studied as a function of penetration depth and incident photon energy. Effective atomic numbers and Kerma relative to air of the selected OSL materials and tissue equivalence were computed and compared with that of water, PMMA and ICRU standard tissues. The buildup factors and kerma relative to air were found dependent upon effective atomic numbers. Buildup factors determined in the present work should be useful in radiation dosimetry, medical diagnostics and therapy, space dosimetry, accident dosimetry and personnel monitoring.

  3. Determination of tissue equivalent materials of a physical 8-year-old phantom for use in computed tomography

    NASA Astrophysics Data System (ADS)

    Akhlaghi, Parisa; Miri Hakimabad, Hashem; Rafat Motavalli, Laleh

    2015-07-01

    This paper reports on the methodology applied to select suitable tissue equivalent materials of an 8-year phantom for use in computed tomography (CT) examinations. To find the appropriate tissue substitutes, first physical properties (physical density, electronic density, effective atomic number, mass attenuation coefficient and CT number) of different materials were studied. Results showed that, the physical properties of water and polyurethane (as soft tissue), B-100 and polyvinyl chloride (PVC) (as bone) and polyurethane foam (as lung) agree more with those of original tissues. Then in the next step, the absorbed doses in the location of 25 thermoluminescent dosimeters (TLDs) as well as dose distribution in one slice of phantom were calculated for original and these proposed materials by Monte Carlo simulation at different tube voltages. The comparisons suggested that at tube voltages of 80 and 100 kVp using B-100 as bone, water as soft tissue and polyurethane foam as lung is suitable for dosimetric study in pediatric CT examinations. In addition, it was concluded that by considering just the mass attenuation coefficient of different materials, the appropriate tissue equivalent substitutes in each desired X-ray energy range could be found.

  4. Gas sensitive materials for gas detection and methods of making

    DOEpatents

    Trakhtenberg, Leonid Israilevich; Gerasimov, Genrikh Nikolaevich; Gromov, Vladimir Fedorovich; Rozenberg, Valeriya Isaakovna

    2014-07-15

    A gas sensitive material comprising SnO.sub.2 nanocrystals doped with In.sub.2O.sub.3 and an oxide of a platinum group metal, and a method of making the same. The platinum group metal is preferably Pd, but also may include Pt, Ru, Ir, and combinations thereof. The SnO.sub.2 nanocrystals have a specific surface of 7 or greater, preferably about 20 m2/g, and a mean particle size of between about 10 nm and about 100 nm, preferably about 40 nm. A gas detection device made from the gas sensitive material deposited on a substrate, the gas sensitive material configured as a part of a current measuring circuit in communication with a heat source.

  5. Gas sensitive materials for gas detection and method of making

    DOEpatents

    Trakhtenberg, Leonid Israilevich; Gerasimov, Genrikh Nikolaevich; Gromov, Vladimir Fedorovich; Rozenberg, Valeriya Isaakovna

    2012-12-25

    A gas sensitive material comprising SnO2 nanocrystals doped with In2O3 and an oxide of a platinum group metal, and a method of making the same. The platinum group metal is preferably Pd, but also may include Pt, Ru, Ir, and combinations thereof. The SnO2 nanocrystals have a specific surface of 7 or greater, preferably about 20 m2/g, and a mean particle size of between about 10 nm and about 100 nm, preferably about 40 nm. A gas detection device made from the gas sensitive material deposited on a substrate, the gas sensitive material configured as a part of a current measuring circuit in communication with a heat source.

  6. Energetic materials and methods of tailoring electrostatic discharge sensitivity of energetic materials

    DOEpatents

    Daniels, Michael A.; Heaps, Ronald J.; Wallace, Ronald S.; Pantoya, Michelle L.; Collins, Eric S.

    2016-11-01

    An energetic material comprising an elemental fuel, an oxidizer or other element, and a carbon nanofiller or carbon fiber rods, where the carbon nanofiller or carbon fiber rods are substantially homogeneously dispersed in the energetic material. Methods of tailoring the electrostatic discharge sensitivity of an energetic material are also disclosed.

  7. IUS materials outgassing condensation effects on sensitive spacecraft surfaces

    NASA Technical Reports Server (NTRS)

    Mullen, C. R.; Shaw, C. G.; Crutcher, E. R.

    1982-01-01

    Four materials used on the inertial upper state (IUS) were subjected to vacuum conditions and heated to near-operational temperatures (93 to 316 C), releasing volatile materials. A fraction of the volatile materials were collected on 25 C solar cells, optical solar reflectors (OSR's) or aluminized Mylar. The contaminated surfaces were exposed to 26 equivalent sun hours of simulated solar ultraviolet (UV) radiation. Measurements of contamination deposit mass, structure, reflectance and effects on solar cell power output were made before and after UV irradiation. Standard total mass loss - volatile condensible materials (TML - VCM) tests were also performed. A 2500 A thick contaminant layer produced by EPDM rubber motor-case insulation outgassing increased the solar absorptance of the OSR's from 0.07 to 0.14, and to 0.18 after UV exposure. An 83,000 A layer caused an increase from 0.07 to 0.21, and then the 0.46 after UV exposure. The Kevlar-epoxy motor-case material outgassing condensation raised the absorptance from 0.07 to 0.13, but UV had no effect. Outgassing from multilayer insulation and carbon-carbon nozzle materials did not affect the solar absorptance of the OSR's.

  8. Evaluation of the water-equivalence of plastic materials in low- and high-energy clinical proton beams.

    PubMed

    Lourenço, A; Shipley, D; Wellock, N; Thomas, R; Bouchard, H; Kacperek, A; Fracchiolla, F; Lorentini, S; Schwarz, M; MacDougall, N; Royle, G; Palmans, H

    2017-05-21

    The aim of this work was to evaluate the water-equivalence of new trial plastics designed specifically for light-ion beam dosimetry as well as commercially available plastics in clinical proton beams. The water-equivalence of materials was tested by computing a plastic-to-water conversion factor, [Formula: see text]. Trial materials were characterized experimentally in 60 MeV and 226 MeV un-modulated proton beams and the results were compared with Monte Carlo simulations using the FLUKA code. For the high-energy beam, a comparison between the trial plastics and various commercial plastics was also performed using FLUKA and Geant4 Monte Carlo codes. Experimental information was obtained from laterally integrated depth-dose ionization chamber measurements in water, with and without plastic slabs with variable thicknesses in front of the water phantom. Fluence correction factors, [Formula: see text], between water and various materials were also derived using the Monte Carlo method. For the 60 MeV proton beam, [Formula: see text] and [Formula: see text] factors were within 1% from unity for all trial plastics. For the 226 MeV proton beam, experimental [Formula: see text] values deviated from unity by a maximum of about 1% for the three trial plastics and experimental results showed no advantage regarding which of the plastics was the most equivalent to water. Different magnitudes of corrections were found between Geant4 and FLUKA for the various materials due mainly to the use of different nonelastic nuclear data. Nevertheless, for the 226 MeV proton beam, [Formula: see text] correction factors were within 2% from unity for all the materials. Considering the results from the two Monte Carlo codes, PMMA and trial plastic #3 had the smallest [Formula: see text] values, where maximum deviations from unity were 1%, however, PMMA range differed by 16% from that of water. Overall, [Formula: see text] factors were deviating more from unity than [Formula: see text] factors

  9. Evaluation of the water-equivalence of plastic materials in low- and high-energy clinical proton beams

    NASA Astrophysics Data System (ADS)

    Lourenço, A.; Shipley, D.; Wellock, N.; Thomas, R.; Bouchard, H.; Kacperek, A.; Fracchiolla, F.; Lorentini, S.; Schwarz, M.; MacDougall, N.; Royle, G.; Palmans, H.

    2017-05-01

    The aim of this work was to evaluate the water-equivalence of new trial plastics designed specifically for light-ion beam dosimetry as well as commercially available plastics in clinical proton beams. The water-equivalence of materials was tested by computing a plastic-to-water conversion factor, {{H}\\text{pl,\\text{w}}} . Trial materials were characterized experimentally in 60 MeV and 226 MeV un-modulated proton beams and the results were compared with Monte Carlo simulations using the FLUKA code. For the high-energy beam, a comparison between the trial plastics and various commercial plastics was also performed using FLUKA and Geant4 Monte Carlo codes. Experimental information was obtained from laterally integrated depth-dose ionization chamber measurements in water, with and without plastic slabs with variable thicknesses in front of the water phantom. Fluence correction factors, {{k}\\text{fl}} , between water and various materials were also derived using the Monte Carlo method. For the 60 MeV proton beam, {{H}\\text{pl,\\text{w}}} and {{k}\\text{fl}} factors were within 1% from unity for all trial plastics. For the 226 MeV proton beam, experimental {{H}\\text{pl,\\text{w}}} values deviated from unity by a maximum of about 1% for the three trial plastics and experimental results showed no advantage regarding which of the plastics was the most equivalent to water. Different magnitudes of corrections were found between Geant4 and FLUKA for the various materials due mainly to the use of different nonelastic nuclear data. Nevertheless, for the 226 MeV proton beam, {{H}\\text{pl,\\text{w}}} correction factors were within 2% from unity for all the materials. Considering the results from the two Monte Carlo codes, PMMA and trial plastic #3 had the smallest {{H}\\text{pl,\\text{w}}} values, where maximum deviations from unity were 1%, however, PMMA range differed by 16% from that of water. Overall, {{k}\\text{fl}} factors were deviating more from unity than {{H

  10. Laboratory measurement of material electrical properties: Extending the application of lumped-circuit equivalent models to 1 GHz

    NASA Astrophysics Data System (ADS)

    Levitskaya, Tsylya M.; Sternberg, Ben K.

    2000-03-01

    For measurements of material electrical properties in a frequency range from 1 kHz to 1 GHz, we used a laboratory method based on the concept of lumped R, L, and C circuit elements. While this method has typically been used at frequencies of less than 100 MHz, we have extended its application up to 1 GHz. The complex electrical parameters of a material, such as resistivity, conductivity, and dielectric permittivity were obtained by measuring magnitude Z and phase ϕ of the sample impedance Z. We relate the material electrical parameters to either series or parallel lumped-circuit equivalent models. Depending on the frequency range, two different designs of the sample holder can be used: (1) a parallel-plate capacitor with disk electrodes, for low frequencies (from 1 kHz to 100 MHz), and (2) a coaxial capacitor, for a broad band up to higher frequencies (from 1 kHz to 1 GHz). Measured values of the sample impedance usually include errors due to effects from the sample holder and its connections to the instrument. These effects, caused by the inductance, resistance, and stray capacitance of the measuring system, are taken into account. Our measurements of several standard materials, including air, Teflon, octanol, butanol, and methanol, showed that the relative standard deviation from the mean for the dielectric permittivity (in the range where it is frequency independent) is typically less than 1%. The difference between our mean values and previously published values for these standard materials is also less than 1%.

  11. Friction, impact, and electrostatic discharge sensitivities of energetic materials

    SciTech Connect

    Wang, P.S.; Hall, G.F.

    1985-05-31

    Impact, friction, and electrostatic discharge sensitivities of energetic materials (explosives and pyrotechnics) used or manufactured at Mound were tested by the ''one-shot'' method. The Bruceton statistical method was used to derive 50% initiation levels, and the results were compared. The materials tested include: PETN, HMX, Plastic Bonded Explosives (PBX), CP, TATB, RX26BB, RX26BH, barium styphnate, LX-15, LX-16, Ti/KClO/sub 4/, TiH/sub 0.65//KClO/sub 4/, TiH/sub 1.65//KClO/sub 4/, Fe/KClO/sub 4/, TiH/sub 1.75//B/CaCrO/sub 4/, Ti/B/CaCrO/sub 4/, B/CaCrO/sub 4/, TiH/sub 0.65//2B, TiH/sub 0.65//3B, 2Ti/B, TiH/sub 1.67//2B, Ti/2B, TiH/sub 1/67//3B, Ti/B, and Ti/3B. Some samples were investigated for aging effects, physical variables, and the effect of manufacturing paramters on sensitivities. The results show that in both friction and impact tests, CP and barium styphnate are the most sensitive; TiH/sub 1.65/KClO/sub 4/, LX-15, TATB and its related materials are the least sensitive; and other materials such as PETN and HMX are in the mid-range. In the electrostatic tests of Ti-based pyrotechnics, a decrease of sensitivity with increasing hydrogen concentration was observed. 20 refs., 12 figs., 7 tabs.

  12. An Earth-Based Equivalent Low Stretch Apparatus to Assess Material Flammability for Microgravity and Extraterrestrial Fire-Safety Applications

    NASA Technical Reports Server (NTRS)

    Olson, S. L.; Beeson, H.; Haas, J. P.

    2003-01-01

    The objective of this project is to modify the standard oxygen consumption (cone) calorimeter (described in ASTM E 1354 and NASA STD 6001 Test 2) to provide a reproducible bench-scale test environment that simulates the buoyant or ventilation flow that would be generated by or around a burning surface in a spacecraft or extraterrestrial gravity level. This apparatus will allow us to conduct normal gravity experiments that accurately and quantitatively evaluate a material's flammability characteristics in the real-use environment of spacecraft or extra-terrestrial gravitational acceleration. The Equivalent Low Stretch Apparatus (ELSA) uses an inverted cone geometry with the sample burning in a ceiling fire configuration that provides a reproducible bench-scale test environment that simulates the buoyant or ventilation flow that would be generated by a flame in a spacecraft or extraterrestrial gravity level. Prototype unit testing results are presented in this paper. Ignition delay times and regression rates for PMMA are presented over a range of radiant heat flux levels and equivalent stretch rates which demonstrate the ability of ELSA to simulate key features of microgravity and extraterrestrial fire behavior.

  13. Highly sensitive resist material for deep x-ray lithography

    NASA Astrophysics Data System (ADS)

    Ehrfeld, Wolfgang; Hessel, Volker; Lehr, Heinz; Loewe, Holger; Schmidt, Martin; Schenk, Rainer

    1997-07-01

    The present paper describes the first chemically amplified negative-tone resist for deep x-ray lithography (DXRL). The choice of the resist material for this new resist has been oriented on the experience of the photo, electron beam and x- ray lithography (XRL) for microelectronic applications. In this work a negative tone resist containing a novolak, a crosslinker and an acid generator was developed by varying the different components. It was found that only few components, which proved to be good in thin films, were suitable for DXRL. The new resist fulfills all technological requirements and shows an increased sensitivity by a factor 15 as compared to the standard resist material, poly(methyl methacrylate). This tremendous increase in sensitivity leads to a huge cost reduction of the DXRL process. Furthermore, an excellent adhesion of this new resist to metallic substrates has been achieved which allows us to fabricate free standing columns with an aspect ratio of 80.

  14. Dual-use applications of infrared sensitive materials

    NASA Astrophysics Data System (ADS)

    Blechman, Barry M.; Lush, Scott C.

    1993-06-01

    High performance infrared focal plane arrays made from sensitive materials such as mercury cadmium telluride grown on a substrate of cadmium zinc telluride have been proposed for use in an extensive variety of military equipment for over a decade. The proposed uses have ranged from early-warning satellites to missile seekers. In this report, we describe and quantify the potential dual-use markets for such detectors.

  15. Edge crack sensitivity of lightweight materials under different load conditions

    NASA Astrophysics Data System (ADS)

    Tsoupis, I.; Merklein, M.

    2016-11-01

    This study addresses the analysis of edge crack sensitivity of DP800 steel and AA5182 aluminum alloy in dependency of punching and machining operation as well as load case of subsequent forming. The inserting of a round hole by punching with defined punch-to- die-clearance, milling and drilling is compared. Subsequent forming is performed by standardized hole expansion test and by Nakajima-tests with three different specimen geometries. Local strain distribution at the surface for Nakajima-tests is measured by optical strain measurement technique and investigated in order to evaluate local deformation before failure. Additionally, resulting hole expansion ratio λ is determined. Significant higher X as well as local strain values ε max are achieved by machined holes. This is directly coupled to higher local formability and stretchability for both materials. Furthermore, the load condition has a strong impact on the edge crack sensitivity of the material. Prior failure is observed with changing stress conditions using different specimen geometries also influencing the reachable maximum failure strain. Higher edge crack sensitivity is observed for DP800, which is in good accordance to the material properties in terms of ductility and strength. These data in dependency of the process parameter can be used for the design of automotive components.

  16. Achieving tunable sensitivity in composite high-energy density materials

    NASA Astrophysics Data System (ADS)

    Rashkeev, Sergey; Tsyshevsky, Roman; Kuklja, Maija

    2015-06-01

    Laser irradiation provides a unique opportunity for selective, predictive, and controlled initiation of energetic materials. We propose a consistent micro-scale mechanism of photoexcitation at the interface, formed by a molecular energetic material and a metal oxide. A specific PETN-MgO model composite is used to illustrate and explain seemingly puzzling experiments on selective laser initiation of energetic materials, which reported that the presence of metal oxide additives triggered the photoinitiation by an unusually low energy. We suggest that PETN photodecomposition is catalyzed by oxygen vacancies (F0 centers) at the MgO surface. The proposed model suggests ways to tune sensitivity of energetic molecular materials to photoinitiation. Our quantum-chemical calculations suggest that the structural defects (e.g., oxygen vacancies) strongly interact with the molecular material (e.g., adsorbed energetic molecules) by inducing a charge transfer at the interface and hence play an imperative role in governing both energy absorption and energy release in the system. Our approach and conclusions provide a solid basis for novel design of energetic interfaces with desired properties and offers a new perspective in the field of explosive materials and devices.

  17. Achieving tunable sensitivity in composite high-energy density materials

    NASA Astrophysics Data System (ADS)

    Kuklja, Maija M.; Tsyshevsky, Roman V.; Rashkeev, Sergey

    2017-01-01

    Laser irradiation provides a unique opportunity for selective, predictive, and controlled initiation of energetic materials. We propose a consistent micro-scale mechanism of photoexcitation at the interface, formed by a molecular energetic material and a metal oxide. A specific PETN-MgO model composite is used to illustrate and explain seemingly puzzling experiments on selective laser initiation of energetic materials, which reported that the presence of metal oxide additives triggered the photoinitiation by an unusually low energy. We suggest that PETN photodecomposition is catalyzed by oxygen vacancies (F0 centers) at the MgO surface. The proposed model suggests ways to tune sensitivity of energetic molecular materials to photoinitiation. Our quantum-chemical calculations suggest that the structural point defects (e.g., oxygen vacancies) strongly interact with the molecular material (e.g., adsorbed energetic molecules) by inducing a charge transfer at the interface and hence play an imperative role in governing both energy absorption and energy release in the system. Our approach and conclusions provide a solid basis for novel design of energetic interfaces with desired properties and offers a new perspective in the field of explosive materials and devices.

  18. Estimating the Equivalent Initial Crack Size in a Particulate Composite Material Under a Multi-Axial Loading Condition

    DTIC Science & Technology

    2002-05-22

    Equivalent Initial Flaw Size Distribution...34 Equivalent Initial Flaw Size Distribution for Notches.in 2024-T3 Aluminum, Accounting for Short Crack Effect," Proceeding of 1997 International Conference on...Structural Safety and Reliability, Kyoto, Japan. 9. Liu, C. T. and Yang, J. N. (2000), ’Determination of the Equivalent Initial Flaw Size

  19. Calculation of Absorbed Dose in Target Tissue and Equivalent Dose in Sensitive Tissues of Patients Treated by BNCT Using MCNP4C

    NASA Astrophysics Data System (ADS)

    Zamani, M.; Kasesaz, Y.; Khalafi, H.; Pooya, S. M. Hosseini

    Boron Neutron Capture Therapy (BNCT) is used for treatment of many diseases, including brain tumors, in many medical centers. In this method, a target area (e.g., head of patient) is irradiated by some optimized and suitable neutron fields such as research nuclear reactors. Aiming at protection of healthy tissues which are located in the vicinity of irradiated tissue, and based on the ALARA principle, it is required to prevent unnecessary exposure of these vital organs. In this study, by using numerical simulation method (MCNP4C Code), the absorbed dose in target tissue and the equiavalent dose in different sensitive tissues of a patiant treated by BNCT, are calculated. For this purpose, we have used the parameters of MIRD Standard Phantom. Equiavelent dose in 11 sensitive organs, located in the vicinity of target, and total equivalent dose in whole body, have been calculated. The results show that the absorbed dose in tumor and normal tissue of brain equal to 30.35 Gy and 0.19 Gy, respectively. Also, total equivalent dose in 11 sensitive organs, other than tumor and normal tissue of brain, is equal to 14 mGy. The maximum equivalent doses in organs, other than brain and tumor, appear to the tissues of lungs and thyroid and are equal to 7.35 mSv and 3.00 mSv, respectively.

  20. Investigation of graphene-based nanoscale radiation sensitive materials

    NASA Astrophysics Data System (ADS)

    Robinson, Joshua A.; Wetherington, Maxwell; Hughes, Zachary; LaBella, Michael, III; Bresnehan, Michael

    2012-06-01

    Current state-of-the-art nanotechnology offers multiple benefits for radiation sensing applications. These include the ability to incorporate nano-sized radiation indicators into widely used materials such as paint, corrosion-resistant coatings, and ceramics to create nano-composite materials that can be widely used in everyday life. Additionally, nanotechnology may lead to the development of ultra-low power, flexible detection systems that can be embedded in clothing or other systems. Graphene, a single layer of graphite, exhibits exceptional electronic and structural properties, and is being investigated for high-frequency devices and sensors. Previous work indicates that graphene-oxide (GO) - a derivative of graphene - exhibits luminescent properties that can be tailored based on chemistry; however, exploration of graphene-oxide's ability to provide a sufficient change in luminescent properties when exposed to gamma or neutron radiation has not been carried out. We investigate the mechanisms of radiation-induced chemical modifications and radiation damage induced shifts in luminescence in graphene-oxide materials to provide a fundamental foundation for further development of radiation sensitive detection architectures. Additionally, we investigate the integration of hexagonal boron nitride (hBN) with graphene-based devices to evaluate radiation induced conductivity in nanoscale devices. Importantly, we demonstrate the sensitivity of graphene transport properties to the presence of alpha particles, and discuss the successful integration of hBN with large area graphene electrodes as a means to provide the foundation for large-area nanoscale radiation sensors.

  1. Sensitivity and performance of azole-based energetic materials.

    PubMed

    Yu, Zijun; Bernstein, Elliot R

    2013-10-24

    Imidazole, pyrazole, 1,2,3-triazole-, 1,2,4-triazole-, and tetrazole-based energetic materials are theoretically investigated by employing density functional theory (DFT). Heats of formation (ΔfH(0)'s) for the studied compounds (298 K) in the gas phase are determined at the B3P86/6-311G (d, p) theory level through isodesmic reactions. The bond dissociation energies (BDEs) corresponding to NO2, NH2, CH3, and Cl removal from carbon or nitrogen positions of the azole ring are also calculated at the B3P86/6-311G (d, p) theory level. The substituent effect of electron-withdrawing (NO2, Cl) and electron-donating (NH2, CH3) groups on the ΔfH(0)s and BDEs is discussed. Both electron-withdrawing groups and electron-donating groups (except the CH3 group) dramatically increase the ΔfH(0)s of these energetic materials when the substituent is at an N position on the azole ring. For substitution at a C atom on the azole ring, electron-withdrawing and electron-donating groups have different effects on the ΔfH(0)s for different azole compounds. A correlation is developed for this series of energetics between impact sensitivity h50% and the defined sensitivity index (SI): based on this empirical relationship and its extrapolation, the impact sensitivities of compounds for which experiments are not available are provided. The promising energetic compounds in each groups, which have potentially good energetic performance and low sensitivity, are 1-amino-2,4,5-trinitroimidazole, 1-amino-3,4,5-trinitropyrazole, 1,4-dinitro-1,2,3-triazole, 1,3-dinitro-1,2,4-triazole, and 1-nitrotetrazole.

  2. Sensitivity and Performance of Azole Based Energetic Materials

    NASA Astrophysics Data System (ADS)

    Yu, Zijun; Bernstein, Elliot

    2014-03-01

    Imidazole, pyrazole, 1,2,3-triazole, 1,2,4-triazole, and tetrazole based energetic materials are theoretically investigated by employing density functional theory (DFT). Heats of formation (ΔfH0 s) for the studied compounds (298 K) in the gas phase are determined at the B3P86/6-311G (d, p) theory level through isodesmic reactions. The bond dissociation energies (BDEs) corresponding to NO2, NH2, CH3, and Cl removal from carbon or nitrogen positions of the azole ring are also calculated at the B3P86/6-311G (d, p) theory level. The substituent effect of electron-withdrawing (NO2, Cl) and electron-donating (NH2, CH3) groups on the ΔfH0 s and BDEs is discussed. Both electron-withdrawing groups and electron-donating groups (except the CH3 group) dramatically increase the ΔfH0 s of these energetic materials when the substituent is at an N position on the azole ring. For substitution at a C atom on the azole ring, electron-withdrawing and electron-donating groups have different effects on the ΔfH0 s for different azole compounds. A correlation is developed for this series of energetics between impact sensitivity h50 % and the defined sensitivity index (SI): based on this empirical relationship and its extrapolation, the impact sensitivities of compounds for which experiments are not available are provided. The promising energetic compounds in each group, which have potentially good energetic performance and low sensitivity, are 1-amino-2,4,5-trinitroimidazole, 1-amino-3,4,5-trinitropyrazole, 1,4-dinitro-1,2,3-triazole, 1,3-dinitro-1,2,4-triazole, 1-nitrotetrazole. U.S. Army Research Office (ARO, FA9550-10-1-0454).

  3. Electrostatic Discharge Sensitivity and Electrical Conductivity of Composite Energetic Materials

    SciTech Connect

    Michael A. Daniels; Daniel J. Prentice; Chelsea Weir; Michelle L. Pantoya; Gautham Ramachandran; Tim Dallas

    2013-02-01

    Composite energetic material response to electrical stimuli was investigated and a correlation between electrical conductivity and ignition sensitivity was examined. The composites consisted of micrometer particle aluminum combined with another metal, metal oxide, or fluoropolymer. Of the nine tested mixtures, aluminum with copper oxide was the only mixture to ignite by electrostatic discharge with minimum ignition energy (MIE) of 25 mJ and an electrical conductivity of 1246.25 nS; two orders of magnitude higher than the next composite. This study showed a similar trend in MIE for ignition triggered by a discharged spark compared with a thermal hot wire source.

  4. Discussion on the Standardization of Shielding MaterialsSensitivity Analysis of Material Compositions

    NASA Astrophysics Data System (ADS)

    Ogata, Tomohiro; Kimura, Ken-ichi; Nakata, Mikihiro; Okuno, Koichi; Hirouchi, Takayuki; Kawano, Naofumi; Oishi, Koji; Tanaka, Ken-ichi; Amano, Toshio; Hirao, Yoshihiro

    2017-09-01

    The overview of standardization activities for shielding materials is described. We propose a basic approach for standardizing material composition used in radiation shielding design for nuclear and accelerator facilities. We have collected concrete composition data from actual concrete samples to organize a representative composition and its variance data. Then the sensitivity analysis of the composition variance has been performed through a simple 1-D dose calculation. Recent findings from the analysis are summarized.

  5. Surface Sensitive Techniques for Advanced Characterization of Luminescent Materials.

    PubMed

    Swart, Hendrik C

    2017-08-04

    The important role of surface sensitive characterization techniques such as Auger electron spectroscopy (AES), X-ray photo electron spectroscopy (XPS), time of flight scanning ion mass spectrometry (TOF-SIMS) and High resolution transmission electron microscopy (HRTEM) for the characterization of different phosphor materials is discussed in this short review by giving selective examples from previous obtained results. AES is used to monitor surface reactions during electron bombardment and also to determine the elemental composition of the surfaces of the materials, while XPS and TOF-SIMS are used for determining the surface chemical composition and valence state of the dopants. The role of XPS to determine the presence of defects in the phosphor matrix is also stated with the different examples. The role of HRTEM in combination with Energy dispersive spectroscopy (EDS) for nanoparticle characterization is also pointed out.

  6. Surface Sensitive Techniques for Advanced Characterization of Luminescent Materials

    PubMed Central

    2017-01-01

    The important role of surface sensitive characterization techniques such as Auger electron spectroscopy (AES), X-ray photo electron spectroscopy (XPS), time of flight scanning ion mass spectrometry (TOF-SIMS) and High resolution transmission electron microscopy (HRTEM) for the characterization of different phosphor materials is discussed in this short review by giving selective examples from previous obtained results. AES is used to monitor surface reactions during electron bombardment and also to determine the elemental composition of the surfaces of the materials, while XPS and TOF-SIMS are used for determining the surface chemical composition and valence state of the dopants. The role of XPS to determine the presence of defects in the phosphor matrix is also stated with the different examples. The role of HRTEM in combination with Energy dispersive spectroscopy (EDS) for nanoparticle characterization is also pointed out. PMID:28777357

  7. A batteryless temperature sensor based on high temperature sensitive material

    NASA Astrophysics Data System (ADS)

    Bakkali, Asma; Pelegri-Sebastia, José; Laghmich, Youssef; Lyhyaoui, Abdelouahid

    2016-05-01

    The major challenge in wireless sensor networks is the reduction of energy consumption. Passive wireless sensor network is an attractive solution for measuring physical parameters in harsh environment for large range of applications requiring sensing devices with low cost of fabrication, small size and long term measurement stability. Batteryless temperature sensing techniques are an active research field. The approach developed in our work holds a promising future for temperature sensor applications in order to successfully reduce the energy consumption. The temperature sensor presented in this paper is based on the electromagnetic transduction principle using the integration of the high temperature sensitive material into a passive structure. Variation in temperature makes the dielectric constant of this material changing, and such modification induces variation in the resonant frequencies of high-Q whispering-gallery modes (WGM) in the millimeter-wave frequency range. Following the results achieved, the proposed device shows a linear response to the increasing temperature and these variations can be remotely detected from a radar interrogation. Contribution to the topical issue "Materials for Energy Harvesting, Conversion and Storage (ICOME 2015) - Elected submissions", edited by Jean-Michel Nunzi, Rachid Bennacer and Mohammed El Ganaoui

  8. Characterization of MOSFET dosimeter angular dependence in three rotational axes measured free-in-air and in soft-tissue equivalent material.

    PubMed

    Koivisto, Juha; Kiljunen, Timo; Wolff, Jan; Kortesniemi, Mika

    2013-09-01

    When performing dose measurements on an X-ray device with multiple angles of irradiation, it is necessary to take the angular dependence of metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters into account. The objective of this study was to investigate the angular sensitivity dependence of MOSFET dosimeters in three rotational axes measured free-in-air and in soft-tissue equivalent material using dental photon energy. Free-in-air dose measurements were performed with three MOSFET dosimeters attached to a carbon fibre holder. Soft tissue measurements were performed with three MOSFET dosimeters placed in a polymethylmethacrylate (PMMA) phantom. All measurements were made in the isocenter of a dental cone-beam computed tomography (CBCT) scanner using 5º angular increments in the three rotational axes: axial, normal-to-axial and tangent-to-axial. The measurements were referenced to a RADCAL 1015 dosimeter. The angular sensitivity free-in-air (1 SD) was 3.7 ± 0.5 mV/mGy for axial, 3.8 ± 0.6 mV/mGy for normal-to-axial and 3.6 ± 0.6 mV/mGy for tangent-to-axial rotation. The angular sensitivity in the PMMA phantom was 3.1 ± 0.1 mV/mGy for axial, 3.3 ± 0.2 mV/mGy for normal-to-axial and 3.4 ± 0.2 mV/mGy for tangent-to-axial rotation. The angular sensitivity variations are considerably smaller in PMMA due to the smoothing effect of the scattered radiation. The largest decreases from the isotropic response were observed free-in-air at 90° (distal tip) and 270° (wire base) in the normal-to-axial and tangent-to-axial rotations, respectively. MOSFET dosimeters provide us with a versatile dosimetric method for dental radiology. However, due to the observed variation in angular sensitivity, MOSFET dosimeters should always be calibrated in the actual clinical settings for the beam geometry and angular range of the CBCT exposure.

  9. Radiation sensitive devices and systems for detection of radioactive materials and related methods

    DOEpatents

    Kotter, Dale K

    2014-12-02

    Radiation sensitive devices include a substrate comprising a radiation sensitive material and a plurality of resonance elements coupled to the substrate. Each resonance element is configured to resonate responsive to non-ionizing incident radiation. Systems for detecting radiation from a special nuclear material include a radiation sensitive device and a sensor located remotely from the radiation sensitive device and configured to measure an output signal from the radiation sensitive device. In such systems, the radiation sensitive device includes a radiation sensitive material and a plurality of resonance elements positioned on the radiation sensitive material. Methods for detecting a presence of a special nuclear material include positioning a radiation sensitive device in a location where special nuclear materials are to be detected and remotely interrogating the radiation sensitive device with a sensor.

  10. Urban biowaste-derived sensitizing materials for caffeine photodegradation.

    PubMed

    Bianco Prevot, A; Baino, F; Fabbri, D; Franzoso, F; Magnacca, G; Nisticò, R; Arques, A

    2017-05-01

    Caffeine-photosensitized degradation has been studied in the presence of bio-based materials derived from urban biowaste after aerobic aging. A peculiar fraction (namely bio-based substances (BBSs)), soluble in all the pH range, has been used as photosensitizing agent. Several caffeine photodegradation tests have been performed, and positive results have been obtained in the presence of BBSs and H2O2, without and with additional Fe(II) (photo-Fenton-like process). Moreover, hybrid magnetite-BBS nanoparticles have been synthesized and characterized, in order to improve the sensitizer recovery and reuse after the caffeine degradation. In the presence of such nanoparticles and H2O2 and Fe(II), the complete caffeine degradation has been attained in very short time. Both homogeneous and heterogeneous processes were run at pH = 5, milder condition compared to the classic photo-Fenton process.

  11. The Discounted Method and Equivalence of Average Criteria for Risk-Sensitive Markov Decision Processes on Borel Spaces

    SciTech Connect

    Cavazos-Cadena, Rolando; Salem-Silva, Francisco

    2010-04-15

    This note concerns discrete-time controlled Markov chains with Borel state and action spaces. Given a nonnegative cost function, the performance of a control policy is measured by the superior limit risk-sensitive average criterion associated with a constant and positive risk sensitivity coefficient. Within such a framework, the discounted approach is used (a) to establish the existence of solutions for the corresponding optimality inequality, and (b) to show that, under mild conditions on the cost function, the optimal value functions corresponding to the superior and inferior limit average criteria coincide on a certain subset of the state space. The approach of the paper relies on standard dynamic programming ideas and on a simple analytical derivation of a Tauberian relation.

  12. The evaluation of neutron and gamma ray dose equivalent distributions in patients and the effectiveness of shield materials for high energy photons radiotherapy facilities.

    PubMed

    Ghassoun, J; Senhou, N

    2012-04-01

    In this study, the MCNP5 code was used to model radiotherapy room of a medical linear accelerator operating at 18 MV and to evaluate the neutron and the secondary gamma ray fluences, the energy spectra and the dose equivalent distributions inside a liquid tissue-equivalent (TE) phantom. The obtained results were compared with measured data published in the literature. Moreover, the shielding effects of various neutron material shields on the radiotherapy room wall were also investigated. Our simulation results showed that paraffin wax containing boron carbide presents enough effectiveness to reduce both neutron and secondary gamma ray doses.

  13. Strain Sensitivity in Single Walled Carbon Nanotubes for Multifunctional Materials

    NASA Technical Reports Server (NTRS)

    Heath, D. M. (Technical Monitor); Smits, Jan M., VI

    2005-01-01

    Single walled carbon nanotubes represent the future of structural aerospace vehicle systems due to their unparalleled strength characteristics and demonstrated multifunctionality. This multifunctionality rises from the CNT's unique capabilities for both metallic and semiconducting electron transport, electron spin polarizability, and band gap modulation under strain. By incorporating the use of electric field alignment and various lithography techniques, a single wall carbon nanotube (SWNT) test bed for measurement of conductivity/strain relationships has been developed. Nanotubes are deposited at specified locations through dielectrophoresis. The circuit is designed such that the central, current carrying section of the nanotube is exposed to enable atomic force microscopy and manipulation in situ while the transport properties of the junction are monitored. By applying this methodology to sensor development a flexible single wall carbon nanotube (SWNT) based strain sensitive device has been developed. Studies of tensile testing of the flexible SWNT device vs conductivity are also presented, demonstrating the feasibility of using single walled HiPCO (high-pressure carbon monoxide) carbon nanotubes as strain sensing agents in a multi-functional materials system.

  14. Elemental Fingerprinting of Materials with Sensitivity at the Atomic Limit

    NASA Astrophysics Data System (ADS)

    Cummings, Marvin; Shirato, Nozomi; Kersell, Heath; Li, Yang; Stripe, Benjamin; Rosenmann, Daniel; Hla, Saw-Wai; Rose, Volker

    2015-03-01

    Variants of scanning probe microscopes have proven tremendously valuable for extracting detailed information about the nature of a sample's surface (atomic, electronic, magnetic), however it has proven difficult to yield chemical information utilizing scanning probe techniques alone. At Argonne National Laboratory's Advanced Photon Source, a new in-situ high-resolution microscopy technique, the synchrotron x-ray scanning tunneling microscope (SXSTM), utilizes x-rays as a chemical, electronic and magnetic probe and the nanofabricated tips of a scanning tunneling microscope as the chemical detector to take full advantage of the sub-nm spatial resolutions that STMs provide. Utilizing the new SXSTM technique, chemical fingerprinting of individual nickel clusters on a Cu(111) surface has been demonstrated with a 2 nm lateral resolution and a sensitivity confined to the first atomic surface layer. In addition, the photoionization cross-section from a single nm-scale Ni cluster has been successfully measured. SXSTM could prove to be a powerful new surface characterization technique, enabling exciting areas of opportunity and discovery in the chemical and materials sciences. This work was funded by the Office of Science Early Career Research Program through the Division of Scientific User Facilities, Office of Basic Energy Sciences, U.S. Department of Energy, through Grant SC70705.

  15. Development of active and sensitive material systems based on composites

    NASA Astrophysics Data System (ADS)

    Asanuma, Hiroshi

    2002-07-01

    This paper describes new concepts proposed by the author to realize active and sensitive structural material systems. Two examples of multifunctional composites were fabricated and evaluated in this study as follows: (1) An active laminate of aluminum plate (works as muscle), epoxy film (as insulator), unidirectional CFRP prepreg (as bone and blood vessel) and copper foil electrode (to apply voltage on CFRP) was made with an embedded optical fiber multiply fractured in the CFRP layer (works as nerve), of which curvature change could be effectively monitored with the fractured optical fiber. (2) A stainless steel fiber/aluminum active composite with embedded Ti oxide/Ti composite fiber was fabricated. The Ti oxide/Ti fiber could work as a sensor for temperature by removing a part of the oxide before embedment to make a metallic contact between the embedded titanium fiber and aluminum matrix to be able to generate thermal electromotive force, and also could work as a sensor for strain and as a heater for actuation. In the both cases, the outputs from their embedded sensors can be used to control their actuations.

  16. Impurity-sensitized luminescence of rare earth-doped materials

    SciTech Connect

    Smentek, Lidia . E-mail: smentek1@aol.com

    2005-02-15

    The accuracy of the theoretical model of impurity-sensitized luminescence in rare earth-doped materials presented here is adjusted to the demands of precise modern experimental techniques. The description is formulated within the double perturbation theory, and it is based on the assumption that electrostatic interactions between the subsystems that take part in the luminescence process are the most important ones. The amplitude of the energy transfer is determined by the contributions that represent the perturbing influence of the crystal-field potential and also electron correlation effects taken into account within the rare earth ions. In this way, the model is defined beyond the standard free ionic system and single configuration approximations. The new contributions to the energy transfer amplitude are expressed in the terms of effective tensor operators, and they contain the perturbing influence of various excited configurations. In order to maintain the high accuracy of the model, the radial integrals of all effective operators are defined within the so-called perturbed function approach. This means that they are evaluated for the complete radial basis sets of one electron functions of given symmetry, including the continuum.

  17. Mutation from guanine to adenine in 25S rRNA at the position equivalent to E. coli A2058 does not confer erythromycin sensitivity in Sacchromyces cerevisae

    PubMed Central

    Bommakanti, Ananth S.; Lindahl, Lasse; Zengel, Janice M.

    2008-01-01

    The macrolide erythromycin binds to the large subunit of the prokaryotic ribosome near the peptidyltransferase center (PTC) and inhibits elongation of new peptide chains beyond a few amino acids. Nucleotides A2058 and A2059 (E. coli numbering) in 23S rRNA play a crucial role in the binding of erythromycin, and mutation of nucleotide A2058 confers erythromycin resistance in both Gram-positive and Gram-negative bacteria. There are high levels of sequence and structural similarity in the PTC of prokaryotic and eukaryotic ribosomes. However, eukaryotic ribosomes are resistant to erythromycin and the presence of a G at the position equivalent to E. coli nucleotide A2058 is believed to be the reason. To test this hypothesis, we introduced a G to A mutation at this position of the yeast Saccharomyces cerevisiae 25S rRNA and analyzed sensitivity toward erythromycin. Neither growth studies nor erythromycin binding assays on mutated yeast ribosomes indicated any erythromycin sensitivity in mutated yeast strains. These results suggest that the identity of nucleotide 2058 is not the only determinant responsible for the difference in erythromycin sensitivity between yeast and prokaryotes. PMID:18218702

  18. Mutation from guanine to adenine in 25S rRNA at the position equivalent to E. coli A2058 does not confer erythromycin sensitivity in Sacchromyces cerevisae.

    PubMed

    Bommakanti, Ananth S; Lindahl, Lasse; Zengel, Janice M

    2008-03-01

    The macrolide erythromycin binds to the large subunit of the prokaryotic ribosome near the peptidyltransferase center (PTC) and inhibits elongation of new peptide chains beyond a few amino acids. Nucleotides A2058 and A2059 (E. coli numbering) in 23S rRNA play a crucial role in the binding of erythromycin, and mutation of nucleotide A2058 confers erythromycin resistance in both gram-positive and gram-negative bacteria. There are high levels of sequence and structural similarity in the PTC of prokaryotic and eukaryotic ribosomes. However, eukaryotic ribosomes are resistant to erythromycin and the presence of a G at the position equivalent to E. coli nucleotide A2058 is believed to be the reason. To test this hypothesis, we introduced a G to A mutation at this position of the yeast Saccharomyces cerevisiae 25S rRNA and analyzed sensitivity toward erythromycin. Neither growth studies nor erythromycin binding assays on mutated yeast ribosomes indicated any erythromycin sensitivity in mutated yeast strains. These results suggest that the identity of nucleotide 2058 is not the only determinant responsible for the difference in erythromycin sensitivity between yeast and prokaryotes.

  19. Comparisons of LET distributions measured in low-earth orbit using tissue-equivalent proportional counters and the position-sensitive silicon-detector telescope (RRMD-III).

    PubMed

    Doke, T; Hayashi, T; Borak, T B

    2001-09-01

    Determinations of the LET distribution, phi(L), of charged particles within a spacecraft in low-Earth orbit have been made. One method used a cylindrical tissue-equivalent proportional counter (TEPC), with the assumption that for each measured event, lineal energy, y, is equal to LET and thus phi(L) = phi(y). The other was based on the direct measurement of LETs for individual particles using a charged-particle telescope consisting of position-sensitive silicon detectors called RRMD-III. There were differences of up to a factor of 10 between estimates of phi(L) using the two methods on the same mission. This caused estimates of quality factor to vary by a factor of two between the two methods.

  20. Estimating raw material equivalents on a macro-level: comparison of multi-regional input-output analysis and hybrid LCI-IO.

    PubMed

    Schoer, Karl; Wood, Richard; Arto, Iñaki; Weinzettel, Jan

    2013-12-17

    The mass of material consumed by a population has become a useful proxy for measuring environmental pressure. The "raw material equivalents" (RME) metric of material consumption addresses the issue of including the full supply chain (including imports) when calculating national or product level material impacts. The RME calculation suffers from data availability, however, as quantitative data on production practices along the full supply chain (in different regions) is required. Hence, the RME is currently being estimated by three main approaches: (1) assuming domestic technology in foreign economies, (2) utilizing region-specific life-cycle inventories (in a hybrid framework), and (3) utilizing multi-regional input-output (MRIO) analysis to explicitly cover all regions of the supply chain. While the first approach has been shown to give inaccurate results, this paper focuses on the benefits and costs of the latter two approaches. We analyze results from two key (MRIO and hybrid) projects modeling raw material equivalents, adjusting the models in a stepwise manner in order to quantify the effects of individual conceptual elements. We attempt to isolate the MRIO gap, which denotes the quantitative impact of calculating the RME of imports by an MRIO approach instead of the hybrid model, focusing on the RME of EU external trade imports. While, the models give quantitatively similar results, differences become more pronounced when tracking more detailed material flows. We assess the advantages and disadvantages of the two approaches and look forward to ways to further harmonize data and approaches.

  1. Polymeric variable optical attenuators based on magnetic sensitive stimuli materials

    NASA Astrophysics Data System (ADS)

    de Pedro, S.; Cadarso, V. J.; Ackermann, T. N.; Muñoz-Berbel, X.; Plaza, J. A.; Brugger, J.; Büttgenbach, S.; Llobera, A.

    2014-12-01

    Magnetically-actuable, polymer-based variable optical attenuators (VOA) are presented in this paper. The design comprises a cantilever which also plays the role of a waveguide and the input/output alignment elements for simple alignment, yet still rendering an efficient coupling. Magnetic properties have been conferred to these micro-opto-electromechanical systems (MOEMS) by implementing two different strategies: in the first case, a magnetic sensitive stimuli material (M-SSM) is obtained by a combination of polydimethylsiloxane (PDMS) and ferrofluid (FF) in ratios between 14.9 wt % and 29.9 wt %. An M-SSM strip under the waveguide-cantilever, defined with soft lithography (SLT), provides the required actuation capability. In the second case, specific volumes of FF are dispensed at the end of the cantilever tip (outside the waveguide) by means of inkjet printing (IJP), obtaining the required magnetic response while holding the optical transparency of the waveguide-cantilever. In the absence of a magnetic field, the waveguide-cantilever is aligned with the output fiber optics and thus the intrinsic optical losses can be obtained. Numerical simulations, validated experimentally, have shown that, for any cantilever length, the VOAs defined by IJP present lower intrinsic optical losses than their SLT counterparts. Under an applied magnetic field (Bapp), both VOA configurations experience a misalignment between the waveguide-cantilever and the output fiber optics. Thus, the proposed VOAs modulate the output power as a function of the cantilever displacement, which is proportional to Bapp. The experimental results for the three different waveguide-cantilever lengths and six different FF concentrations (three per technology) show maximum deflections of 220 µm at 29.9 wt % of FF for VOASLT and 250 µm at 22.3 wt % FF for VOAIJP, at 0.57 kG for both. These deflections provide maximum actuation losses of 16.1 dB and 18.9 dB for the VOASLT and VOAIJP

  2. Impact sensitivity of materials in contact with liquid and gaseous oxygen at high pressure

    NASA Technical Reports Server (NTRS)

    Schwinghamer, R. J.

    1972-01-01

    As a result of the Apollo 13 incident, increased emphasis is being placed on materials compatibility in a high pressure GOX environment. It is known that in addition to impact sensitivity of materials, approximately adiabatic compression conditions can contrive to induce materials reactivity. Test runs at high pressure using the ABMA tester indicate the following: (1) The materials used in the tests showed an inverse relationship between thickness and impact sensitivity. (2) Several materials tested exhibited greater impact sensitivity in GOX than in LOX. (3) The impact sensitivity of the materials tested in GOX, at the pressures tested, showed enhanced impact sensitivity with higher pressure. (4) The rank ordering of the materials tested in LOX up to 1000 psia is the same as the rank ordering resulting from tests in LOX at 14.7 psia.

  3. Current trends in materials for dye sensitized solar cells.

    PubMed

    Faccio, Ricardo; Fernández-Werner, Luciana; Pardo, Helena; Mombré, Alvaro W

    2011-01-01

    Here, we intend to review those patents related with the technology of dye sensitized solar cells. In particular we discuss patents and papers that enable metal oxide layer to be more controllable and feasible for applications, and new and innovative dyes, sensitizers and electrolytes with promising features. Finally various methods were reviewed for fabricating semiconductor layers and complete DSSC devices focusing on the mass production of photovoltaic cells.

  4. Neutron dose equivalent meter

    DOEpatents

    Olsher, Richard H.; Hsu, Hsiao-Hua; Casson, William H.; Vasilik, Dennis G.; Kleck, Jeffrey H.; Beverding, Anthony

    1996-01-01

    A neutron dose equivalent detector for measuring neutron dose capable of accurately responding to neutron energies according to published fluence to dose curves. The neutron dose equivalent meter has an inner sphere of polyethylene, with a middle shell overlying the inner sphere, the middle shell comprising RTV.RTM. silicone (organosiloxane) loaded with boron. An outer shell overlies the middle shell and comprises polyethylene loaded with tungsten. The neutron dose equivalent meter defines a channel through the outer shell, the middle shell, and the inner sphere for accepting a neutron counter tube. The outer shell is loaded with tungsten to provide neutron generation, increasing the neutron dose equivalent meter's response sensitivity above 8 MeV.

  5. Simulation of High-Latitude Hydrological Processes in the Torne-Kalix Basin: PILPS Phase 2(e). 3; Equivalent Model Representation and Sensitivity Experiments

    NASA Technical Reports Server (NTRS)

    Bowling, Laura C.; Lettenmaier, Dennis P.; Nijssen, Bart; Polcher, Jan; Koster, Randal D.; Lohmann, Dag; Houser, Paul R. (Technical Monitor)

    2002-01-01

    The Project for Intercomparison of Land Surface Parameterization Schemes (PILPS) Phase 2(e) showed that in cold regions the annual runoff production in Land Surface Schemes (LSSs) is closely related to the maximum snow accumulation, which in turn is controlled in large part by winter sublimation. To help further explain the relationship between snow cover, turbulent exchanges and runoff production, a simple equivalent model-(SEM) was devised to reproduce the seasonal and annual fluxes simulated by 13 LSSs that participated in PILPS Phase 2(e). The design of the SEM relates the annual partitioning of precipitation and energy in the LSSs to three primary parameters: snow albedo, effective aerodynamic resistance and evaporation efficiency. Isolation of each of the parameters showed that the annual runoff production was most sensitive to the aerodynamic resistance. The SEM was somewhat successful in reproducing the observed LSS response to a decrease in shortwave radiation and changes in wind speed forcings. SEM parameters derived from the reduced shortwave forcings suggested that increased winter stability suppressed turbulent heat fluxes over snow. Because winter sensible heat fluxes were largely negative, reductions in winter shortwave radiation imply an increase in annual average sensible heat.

  6. Materials with low DC magnetic susceptibility for sensitive magnetic measurements

    NASA Astrophysics Data System (ADS)

    Khatiwada, R.; Dennis, L.; Kendrick, R.; Khosravi, M.; Peters, M.; Smith, E.; Snow, W. M.

    2016-02-01

    Materials with very low DC magnetic susceptibility have many scientific applications. To our knowledge however, relatively little research has been conducted with the goal to produce a totally nonmagnetic material. This phrase in our case means after spatially averaging over macroscopic volumes, it possesses an average zero DC magnetic susceptibility. We report measurements of the DC magnetic susceptibility of three different types of nonmagnetic materials at room temperature: (I) solutions of paramagnetic salts and diamagnetic liquids, (II) liquid gallium-indium alloys and (III) pressed powder mixtures of tungsten and bismuth. The lowest measured magnetic susceptibility among these candidate materials is in the order of 10-9 cgs volume susceptibility units, about two orders of magnitude smaller than distilled water. In all cases, the measured concentration dependence of the magnetic susceptibility is consistent with that expected for the weighted sum of the susceptibilities of the separate components within experimental error. These results verify the well-known Wiedemann additivity law for the magnetic susceptibility of inert mixtures of materials and thereby realize the ability to produce materials with small but tunable magnetic susceptibility. For our particular scientific application, we are also looking for materials with the largest possible number of neutrons and protons per unit volume. The gallium-indium alloys fabricated and measured in this work possess to our knowledge the smallest ratio of volume magnetic susceptibility to nucleon number density per unit volume for a room temperature liquid, and the tungsten-bismuth pressed powder mixtures possess to our knowledge the smallest ratio of volume magnetic susceptibility to nucleon number density per unit volume for a room temperature solid. This ratio is a figure of merit for a certain class of precision experiments that search for possible exotic spin-dependent forces of Nature.

  7. Organometal halide perovskites as useful materials in sensitized solar cells.

    PubMed

    Singh, Surya Prakash; Nagarjuna, P

    2014-04-14

    Organometal halide perovskites offer dual potential properties as a light harvester and at the same time as a hole conductor in inorganic-organic hybrid heterojunction solar cells. The sequential deposition route provides a power conversion efficiency of 15% under standard AM1.5G test conditions. In this perspective, we will briefly summarize the development of perovskite-sensitized solar cells from their first report up to the present.

  8. Sensitivity Analysis of Down Woody Material Data Processing Routines

    Treesearch

    Christopher W. Woodall; Duncan C. Lutes

    2005-01-01

    Weight per unit area (load) estimates of Down Woody Material (DWM) are the most common requests by users of the USDA Forest Service's Forest Inventory and Analysis (FIA) program's DWM inventory. Estimating of DWM loads requires the uniform compilation of DWM transect data for the entire United States. DWM weights may vary by species, level of decay, woody...

  9. On the development of survival criteria for rate sensitive materials.

    PubMed

    Eppinger, R H; Takhounts, E G

    2000-11-01

    The evaluation and mitigation of injury in the automotive crash environment is often achieved by monitoring and limiting the magnitude of forces and/or moments being applied to or transmitted through dummy structures representing particular portions of the human anatomy. Examples of body areas where this is the practice are the neck, the thoracic and lumbar spine, the pelvis, as well as the upper and lower extremities. Implicit within this process is the assumption that the observed forces are directly proportional to local failure metrics such as stress and/or strain. However, a variety of experimental efforts have demonstrated that many of these anatomical structures exhibit, to various degrees, viscoelastic behavior and time or rate dependent failure properties. This work develops a methodology that generalizes the results of various experimental observations. First, a particular material's viscoelastic constitutive properties are mathematically characterized by developing a constitutive relationship relating experimentally observed stress time histories to applied strain, and strain rate time histories. This constitutive relationship and a novel technique of "back integration" are employed to develop the material's creep compliance response. A Duhamel Integral relationship is used to predict the material's actual strain time history given its observed stress-rate time history and creep compliance characteristic. This then allows casting the material's loading history into its actual time dependent stress/strain space and determining if failure conditions have been exceeded. Both the theoretical development of this methodology and the effects of its application to real world crash circumstances are presented.

  10. Spectroscopic ellipsometry as a sensitive monitor of materials contamination

    NASA Technical Reports Server (NTRS)

    Hale, Jeffrey S.; Hilfiker, James N.; Spady, Blaine; Synowicki, R.; Woollam, John A.

    1995-01-01

    Spectroscopic ellipsometry is demonstrated to be extremely sensitive to contamination layers in the thickness range from 0.1 nm to 10 microns. In the present experiments we deposit either a thin lubricating oil (WD-40) or mineral oil continuously onto Ir, Cu, Al, Au, and V substrates from a bubbler, and monitor its thickness growth from sub-nanometer to tens of nanometers as a function of time. Re-evaporation of contaminant oils is also monitored in real-time by ellipsometry.

  11. Gyrokinetic equivalence

    NASA Astrophysics Data System (ADS)

    Parra, Felix I.; Catto, Peter J.

    2009-06-01

    We compare two different derivations of the gyrokinetic equation: the Hamiltonian approach in Dubin D H E et al (1983 Phys. Fluids 26 3524) and the recursive methodology in Parra F I and Catto P J (2008 Plasma Phys. Control. Fusion 50 065014). We prove that both approaches yield the same result at least to second order in a Larmor radius over macroscopic length expansion. There are subtle differences in the definitions of some of the functions that need to be taken into account to prove the equivalence.

  12. An Earth-Based Equivalent Low Stretch Apparatus to Assess Material Flammability for Microgravity & Extraterrestrial Fire-Safety Applications

    NASA Technical Reports Server (NTRS)

    Olson, S. L.; Beeson, H.; Haas, J.

    2001-01-01

    One of the performance goals for NASA's enterprise of Human Exploration and Development of Space (HEDS) is to develop methods, data bases, and validating tests for material flammability characterization, hazard reduction, and fire detection/suppression strategies for spacecraft and extraterrestrial habitats. This work addresses these needs by applying the fundamental knowledge gained from low stretch experiments to the development of a normal gravity low stretch material flammability test method. The concept of the apparatus being developed uses the low stretch geometry to simulate the conditions of the extraterrestrial environment through proper scaling of the sample dimensions to reduce the buoyant stretch in normal gravity. The apparatus uses controlled forced-air flow to augment the low stretch to levels which simulate Lunar or Martian gravity levels. In addition, the effect of imposed radiant heat flux on material flammability can be studied with the cone heater. After breadboard testing, the apparatus will be integrated into NASA's White Sands Test Facility's Atmosphere-Controlled Cone Calorimeter for evaluation as a new materials screening test method.

  13. The Equivalent Flat Nose Diameter of Hemispherical Nose Cylindrical Projectiles for Impact Induced Detonation of Energetic Materials

    DTIC Science & Technology

    1992-12-01

    greater than OCR and VI/USB respectively to being somewhat smaller (Figs. 6, 7, and 8). This may be caused by the projectile material behavior since PS... Eric N. and Ramsey, John B.; "Spherical Projectile Impact on Explosives", Paper presented at The Ninth Symposium aInternational) on Detonation Aug. 28...S. Army Ballistics Research Laboratory, Aberdeen Proving Ground, MD, Report No. 0121, July 1957. 8. Wilbeck, James S.; "Impact Behavior of Low

  14. Systematic comparison of adeno-associated virus and biotinylated dextran amine reveals equivalent sensitivity between tracers and novel projection targets in the mouse brain.

    PubMed

    Wang, Quanxin; Henry, Alex M; Harris, Julie A; Oh, Seung Wook; Joines, Kevin M; Nyhus, Julie; Hirokawa, Karla E; Dee, Nick; Mortrud, Marty; Parry, Sheana; Ouellette, Benjamin; Caldejon, Shiella; Bernard, Amy; Jones, Allan R; Zeng, Hongkui; Hohmann, John G

    2014-06-15

    As an anterograde neuronal tracer, recombinant adeno-associated virus (AAV) has distinct advantages over the widely used biotinylated dextran amine (BDA). However, the sensitivity and selectivity of AAV remain uncharacterized for many brain regions and species. To validate this tracing method further, AAV (serotype 1) was systematically compared with BDA as an anterograde tracer by injecting both tracers into three cortical and 15 subcortical regions in C57BL/6J mice. Identical parameters were used for our sequential iontophoretic injections, producing injections of AAV that were more robust in size and in density of neurons infected compared with those of BDA. However, these differences did not preclude further comparison between the tracers, because the pairs of injections were suitably colocalized and contained some percentage of double-labeled neurons. A qualitative analysis of projection patterns showed that the two tracers behave very similarly when injection sites are well matched. Additionally, a quantitative analysis of relative projection intensity for cases targeting primary motor cortex (MOp), primary somatosensory cortex (SSp), and caudoputamen (CP) showed strong agreement in the ranked order of projection intensities between the two tracers. A detailed analysis of the projections of two brain regions (SSp and MOp) revealed many targets that have not previously been described in the mouse or rat. Minor retrograde labeling of neurons was observed in all cases examined, for both AAV and BDA. Our results show that AAV has actions equivalent to those of BDA as an anterograde tracer and is suitable for analysis of neural circuitry throughout the mouse brain. Copyright © 2014 Wiley Periodicals, Inc.

  15. Determination of effective atomic numbers from mass attenuation coefficients of tissue-equivalent materials in the energy range 60 keV-1.33 MeV

    NASA Astrophysics Data System (ADS)

    Amin, Noorfatin Aida B.; Zukhi, J.; Kabir, N. A.; Zainon, R.

    2017-05-01

    The main aim of this study was to establish a cost-effective tissue-equivalent material for phantom fabrication. Effective atomic numbers (Zeff) and effective electron densities (Neff) were calculated based on mass attenuation coefficient values. The linear and mass attenuation coefficients of two samples of paraffin wax and NaCl compositions were measured using Si detector for NaI (Tl) detector of 1.5” resources. Radioactive source was placed in front of detector and the sample was placed between the source and the photomultiplier tube (PMT) of the detector. The real time was set for 6000 seconds. The photopeak, full width at half maximum (FWHM) and net area of photopeak were measured using Meastro software. The attenuation coefficient values obtained from this study were used to calculate Zeff and Neff of paraffin wax and NaCl compositions. The measured results were compared with the theoretical values from XCOM and ICRU Report 44. The relative percentage difference of mass attenuation coefficients between experimental and human tissue for both paraffin wax and NaCl mixture are below 5%, whereas the relative percentage difference of Zeff and Neff are above 5%. The measured values of Zeff and Neff of paraffin wax and NaCl help us to establish the optimal mixtures to fabricate a cost-effective tissue-equivalent material.

  16. An efficient method to predict and include Bragg curve degradation due to lung-equivalent materials in Monte Carlo codes by applying a density modulation

    NASA Astrophysics Data System (ADS)

    Baumann, Kilian-Simon; Witt, Matthias; Weber, Uli; Engenhart-Cabillic, Rita; Zink, Klemens

    2017-05-01

    Sub-millimetre-sized heterogeneities such as lung parenchyma cause Bragg peak degradation which can lead to an underdose of the tumor and an overdose of healthy tissue when not accounted for in treatment planning. Since commonly used treatment-planning CTs do not resolve the fine structure of lungs, this degradation can hardly be considered. We present a mathematical model capable of predicting and describing Bragg peak degradation due to a lung-equivalent geometry consisting of sub-millimetre voxels filled with either lung tissue or air. The material characteristic ‘modulation power’ is introduced to quantify the Bragg peak degradation. A strategy was developed to transfer the modulating effects of such fine structures to rougher structures such as 2 mm thick CT voxels, which is the resolution of typically used CTs. This is done by using the modulation power to derive a density distribution applicable to these voxels. By replacing the previously used sub-millimetre voxels by 2 mm thick voxels filled with lung tissue and modulating the lung tissue’s density in each voxel individually, we were able to reproduce the Bragg peak degradation. Hence a solution is found to include Bragg curve degradation due to lung-equivalent materials in Monte Carlo-based treatment-planning systems.

  17. SU-E-J-210: Characterizing Tissue Equivalent Materials for the Development of a Dual MRI-CT Heterogeneous Anthropomorphic Phantom Designed Specifically for MRI Guided Radiotherapy Systems

    SciTech Connect

    Steinmann, A; Stafford, R; Yung, J; Followill, D

    2015-06-15

    Purpose: MRI guided radiotherapy (MRIgRT) is an emerging technology which will eventually require a proficient quality auditing system. Due to different principles in which MR and CT acquire images, there is a need for a multi-imaging-modality, end-to-end QA phantom for MRIgRT. The purpose of this study is to identify lung, soft tissue, and tumor equivalent substitutes that share similar human-like CT and MR properties (i.e. Hounsfield units and relaxation times). Methods: Materials of interested such as common CT QA phantom materials, and other proprietary gels/silicones from Polytek, SmoothOn, and CompositeOne were first scanned on a GE 1.5T Signa HDxT MR. Materials that could be seen on both T1-weighted and T2-weighted images were then scanned on a GE Lightspeed RT16 CT simulator and a GE Discovery 750HD CT scanner and their HU values were then measured. The materials with matching HU values of lung (−500 to −700HU), muscle (+40HU) and soft tissue (+100 to +300HU) were further scanned on GE 1.5T Signa HDx to measure their T1 and T2 relaxation times from varying parameters of TI and TE. Results: Materials that could be visualized on T1-weighted and T2-weighted images from a 1.5T MR unit and had an appropriate average CT number, −650, −685, 46,169, and 168 HUs were: compressed cork saturated with water, Polytek Platsil™ Gel-00 combined with mini styrofoam balls, radiotherapy bolus material, SmoothOn Dragon-Skin™ and SmoothOn Ecoflex™, respectively. Conclusion: Post processing analysis is currently being performed to accurately map T1 and T2 values for each material tested. From previous MR visualization and CT examinations it is expected that Dragon-Skin™, Ecoflex™ and bolus will have values consistent with tissue and tumor substitutes. We also expect compressed cork statured with water, and Polytek™-styrofoam combination to have approximate T1 and T2 values suitable for lung-equivalent materials.

  18. An elastically compressible phantom material with mechanical and x-ray attenuation properties equivalent to breast tissue

    NASA Astrophysics Data System (ADS)

    Price, B. D.; Gibson, A. P.; Tan, L. T.; Royle, G. J.

    2010-02-01

    We have developed a novel phantom material: a solution of polyvinyl alcohol (PVAL) in ethanol and water, freeze-thawed to produce a solid yet elastically compressible gel. The x-ray attenuation and mechanical properties of these gels are compared with published measurements of breast tissue. Gels with PVAL concentrations from 5 to 20% w/v were produced. The linear x-ray attenuation coefficients of these gels range from 0.76 to 0.86 cm-1 at 17.5 keV, increasing with PVAL concentration. These values are very similar to the published values of breast tissue at this energy, 0.8-0.9 cm-1. Under compression cancerous breast tissue is approximately ten times stiffer than healthy breast tissue. The Young's moduli of the gels increase with PVAL concentration. Varying the PVAL concentration from 7.5 to 20% w/v produces gels with Young's moduli from 20 to 220 kPa at 15% strain. These values are characteristic of normal and cancerous breast tissue, respectively.

  19. SU-E-T-663: Radiation Properties of a Water-Equivalent Material Formulated Using the Stoichiometric Analysis Method in Heavy Charged Particle Therapy

    SciTech Connect

    Yohannes, I; Vasiliniuc, S; Hild, S; Graeff, C; Langner, O; Bert, C

    2015-06-15

    Purpose: A material has been designed to be employed as water-equivalent in particle therapy using a previously established stoichiometric analysis method (SAM). After manufacturing, experimental verification of the material’s water-equivalent path length (WEPL) and analysis of its total inelastic nuclear interaction cross sections for proton beams were performed. Methods: Using the SAM, we optimized the material composed of three base materials, i.e., polyurethane, calcium carbonate and microspheres. From the elemental composition of the compound, electron density, linear attenuation coefficients, particle stopping powers and inelastic nuclear cross sections for protons using data from ICRU 63 were calculated. The calculations were then compared to Hounsfield units (HUs) measured with 350 mAs at 80, 100, 120 and 140 kV and the WEPLs measured with three different ions: proton (106.8 MeV/u), helium (107.93 MeV/u) and carbon (200.3 MeV/u). Results: The material’s measured HUs (0.7±3.0 to 2.6±6.2 HU) as well as its calculated relative electron density (1.0001) are in close agreement with water as reference. The WEPLs measured on a 20.00 mm thick target were 20.16±0.12, 20.29±0.12 and 20.38±0.12 mmH2O for proton, helium and carbon ions, respectively. Within measurement uncertainties, these values verified the calculated WEPLs of 20.28 mmH2O (proton), 20.28 mmH2O (helium) and 20.26 mmH2O (carbon). Moreover, the calculated proton inelastic cross sections of the material differed only by 0.89% (100 MeV/u) and 0.01% (200 MeV/u) when compared to water. Conclusion: The SAM is capable of optimizing material with defined properties, e.g., HU, electron density, WEPL and inelastic nuclear interaction cross section for particle therapy. Such material will have a wide range of applications amongst others absolute dosimetry. This work was supported by grant ZIM KF2137107AK4 from the German Federal Ministry for Economic Affairs and Energy.

  20. An Energy-Equivalent d+/d− Damage Model with Enhanced Microcrack Closure-Reopening Capabilities for Cohesive-Frictional Materials

    PubMed Central

    Cervera, Miguel; Tesei, Claudia

    2017-01-01

    In this paper, an energy-equivalent orthotropic d+/d− damage model for cohesive-frictional materials is formulated. Two essential mechanical features are addressed, the damage-induced anisotropy and the microcrack closure-reopening (MCR) effects, in order to provide an enhancement of the original d+/d− model proposed by Faria et al. 1998, while keeping its high algorithmic efficiency unaltered. First, in order to ensure the symmetry and positive definiteness of the secant operator, the new formulation is developed in an energy-equivalence framework. This proves thermodynamic consistency and allows one to describe a fundamental feature of the orthotropic damage models, i.e., the reduction of the Poisson’s ratio throughout the damage process. Secondly, a “multidirectional” damage procedure is presented to extend the MCR capabilities of the original model. The fundamental aspects of this approach, devised for generic cyclic conditions, lie in maintaining only two scalar damage variables in the constitutive law, while preserving memory of the degradation directionality. The enhanced unilateral capabilities are explored with reference to the problem of a panel subjected to in-plane cyclic shear, with or without vertical pre-compression; depending on the ratio between shear and pre-compression, an absent, a partial or a complete stiffness recovery is simulated with the new multidirectional procedure. PMID:28772793

  1. An Energy-Equivalent d⁺/d(-) Damage Model with Enhanced Microcrack Closure-Reopening Capabilities for Cohesive-Frictional Materials.

    PubMed

    Cervera, Miguel; Tesei, Claudia

    2017-04-20

    In this paper, an energy-equivalent orthotropic d⁺/d(-) damage model for cohesive-frictional materials is formulated. Two essential mechanical features are addressed, the damage-induced anisotropy and the microcrack closure-reopening (MCR) effects, in order to provide an enhancement of the original d⁺/d(-) model proposed by Faria et al. 1998, while keeping its high algorithmic efficiency unaltered. First, in order to ensure the symmetry and positive definiteness of the secant operator, the new formulation is developed in an energy-equivalence framework. This proves thermodynamic consistency and allows one to describe a fundamental feature of the orthotropic damage models, i.e., the reduction of the Poisson's ratio throughout the damage process. Secondly, a "multidirectional" damage procedure is presented to extend the MCR capabilities of the original model. The fundamental aspects of this approach, devised for generic cyclic conditions, lie in maintaining only two scalar damage variables in the constitutive law, while preserving memory of the degradation directionality. The enhanced unilateral capabilities are explored with reference to the problem of a panel subjected to in-plane cyclic shear, with or without vertical pre-compression; depending on the ratio between shear and pre-compression, an absent, a partial or a complete stiffness recovery is simulated with the new multidirectional procedure.

  2. Toward interaction of sensitizer and functional moieties in hole-transporting materials for efficient semiconductor-sensitized solar cells.

    PubMed

    Im, Sang Hyuk; Lim, Choong-Sun; Chang, Jeong Ah; Lee, Yong Hui; Maiti, Nilkamal; Kim, Hi-Jung; Nazeeruddin, Md K; Grätzel, Michael; Seok, Sang Il

    2011-11-09

    Sb(2)S(3)-sensitized mesoporous-TiO(2) solar cells using several conjugated polymers as hole-transporting materials (HTMs) are fabricated. We found that the cell performance was strongly correlated with the chemical interaction at the interface of Sb(2)S(3) as sensitizer and the HTMs through the thiophene moieties, which led to a higher fill factor (FF), open-circuit voltage (V(oc)), and short-circuit current density (J(sc)). With the application of PCPDTBT (poly(2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b']dithiophene)-alt-4,7(2,1,3-benzothiadiazole)) as a HTM in a Sb(2)S(3)-sensitized solar cell, overall power conversion efficiencies of 6.18, 6.57, and 6.53% at 100, 50, and 10% solar irradiation, respectively, were achieved with a metal mask.

  3. Establishing Substantial Equivalence: Transcriptomics

    NASA Astrophysics Data System (ADS)

    Baudo, María Marcela; Powers, Stephen J.; Mitchell, Rowan A. C.; Shewry, Peter R.

    Regulatory authorities in Western Europe require transgenic crops to be substantially equivalent to conventionally bred forms if they are to be approved for commercial production. One way to establish substantial equivalence is to compare the transcript profiles of developing grain and other tissues of transgenic and conventionally bred lines, in order to identify any unintended effects of the transformation process. We present detailed protocols for transcriptomic comparisons of developing wheat grain and leaf material, and illustrate their use by reference to our own studies of lines transformed to express additional gluten protein genes controlled by their own endosperm-specific promoters. The results show that the transgenes present in these lines (which included those encoding marker genes) did not have any significant unpredicted effects on the expression of endogenous genes and that the transgenic plants were therefore substantially equivalent to the corresponding parental lines.

  4. Sensitivity improvement of optical-fiber temperature sensor with solid cladding material based on multimode interference

    NASA Astrophysics Data System (ADS)

    Fukano, Hideki; Kushida, Yohei; Taue, Shuji

    2015-03-01

    We have developed a simple, high-sensitivity optical-fiber temperature sensor based on multimode interference (MMI). The fabricated MMI structure comprises three segmented fibers: a single-mode fiber (SMF); a large-core multimode fiber (MMF), whose outer surface is coated with a temperature-sensitive material; and another SMF. Fluoroacrylate and silicone rubber are tested as temperature-sensitive cladding materials. The silicone rubber coating exhibits a large shift in interference wavelength with temperature, producing a very fine temperature resolution as low as 0.01 °C.

  5. Sensitivity of tire response to variations in material and geometric parameters

    NASA Technical Reports Server (NTRS)

    Noor, Ahmed K.; Tanner, John A.; Peters, Jeanne M.

    1992-01-01

    A computational procedure is presented for evaluating the analytic sensitivity derivatives of the tire response with respect to material and geometric parameters of the tire. The tire is modeled by using a two-dimensional laminated anisotropic shell theory with the effects of variation in material and geometric parameters included. The computational procedure is applied to the case of uniform inflation pressure on the Space Shuttle nose-gear tire when subjected to uniform inflation pressure. Numerical results are presented showing the sensitivity of the different response quantities to variations in the material characteristics of both the cord and the rubber.

  6. Effect of hafnium concentration on nuclear performance of blanket materials containing zirconium: a sensitivity analysis of TBR to hafnium content in lithium metazirconate

    NASA Astrophysics Data System (ADS)

    Cepraga, D. G.; Panini, G.; Diamanti, D.; Cambi, G.; Costa, M.; Cavallone, G.; Bruzzi, L.

    1994-09-01

    The reduction of hafnium content in blanket materials containing zirconium is costly. Therefore, a sensitivity analysis was performed to estimate the impact of hafnium content on nuclear properties of lithium metazirconate, a promising breeder material candidate for fusion reactors. This paper summarises the results of extensive shielding neutronic analysis and transmutation-activation calculations aiming to evaluate the tritium breeding ratio, the inventories of various radionuclides, and the surface γ-dose rate. Attention has been mainly focused on the activation inventory variations resulting from hafnium content in lithium metazirconate breeding material. Different design configurations including homogenised solid breeder mixtures of Li 2ZrO 3 and structural materials and a separate beryllium multiplierr zone have been assessed. Hf contents up to 3% have been assessed, resulting in a TBR reduction up to 10%. The Hf content provokes a noticeable increase of the level of the equivalent contact dose.

  7. Photopolymer material sensitized by xanthene dyes for holographic recording using forbidden singlet-triplet electronic transitions

    NASA Astrophysics Data System (ADS)

    Shelkovnikov, Vladimir; Vasiljev, Evgeny; Russkih, Vladimlen; Berezhnaya, Viktoria

    2016-07-01

    A new holographic photopolymer material is developed. The photopolymer material is sensitized by dyes of xanthene and thioxanthene series which contain iodine and bromine heavy atoms. Holographic recording was carried out during excitation of forbidden singlet-triplet electron transitions of dyes. Thioerythrosin triethylammonium was identified as the most effective sensitizer among a number of tested dyes. The spectral absorption area of the singlet-triplet electronic transition of the dye is conveyed in the red spectral range from 600 to 700 nm. The sensitivity of the photopolymer material to radiation with 633 nm wavelength is 180 mJ cm-2. Optimization of concentration of the main components of the photopolymer compositions was carried out in order to achieve maximum efficiency of holographic recording.

  8. Equivalence of conventional anti-picryl T suppressor factor in the contact sensitivity system and monoclonal anti-NP TsF3: their final non-specific effect via the T acceptor cell.

    PubMed

    Asherson, G L; Dorf, M E; Colizzi, V; Zembala, M; James, B M

    1984-11-01

    There is considerable confusion over whether the antigen-specific T suppressor factors (TsF) described by different authors are indeed equivalent. This paper investigates whether monoclonal TsF3, obtained from hybridomas derived from mice injected subcutaneously with NP derived spleen cells, is functionally equivalent to the conventional T suppressor factor, produced by mice injected intravenously with chemically reactive, water soluble haptene (picrylsulphonic acid and oxazolone thioglycolic acid). Comparison of monoclonal anti-NP TsF3 with conventional anti-picryl and anti-oxazolone T suppressor factor showed that both armed the non-specific T acceptor cell (Tacc) which was sensitive to cyclophosphamide and adult thymectomy. Moreover, non-specific inhibitor (nsINH) of the transfer of contact sensitivity was released when antigen, together with major histocompatibility complex products (MHC), reacted with conventional or monoclonal TsF on the surface of the non-specific T acceptor cell. The interaction of monoclonal TsF3 with antigen, which led to the release of NsINH, required the presence of MHC and was I-J restricted. However, there was no Igh-1 restriction. The equivalence of conventional anti-picryl and anti-oxazolone TsF has been demonstrated by arming the Tacc with a mixture of these two suppressor factors, and then triggering the release of nsINH with the mixed haptene 'picryl-oxazolone-lysine' which crosslinks separate molecules of TsF. A similar equivalence of conventional anti-oxazolone TsF and monoclonal anti-NP TsF3 was demonstrated using the mixed hapten 'NP-oxazolone-lysine' to trigger the release of nsINH. It was concluded that monoclonal TsF3 and conventional TsF were equivalent, and that both had an indirect mode of action through the non-specific T acceptor cell which led to the production of non-specific inhibitor.

  9. Equivalence of conventional anti-picryl T suppressor factor in the contact sensitivity system and monoclonal anti-NP TsF3: their final non-specific effect via the T acceptor cell.

    PubMed Central

    Asherson, G L; Dorf, M E; Colizzi, V; Zembala, M; James, B M

    1984-01-01

    There is considerable confusion over whether the antigen-specific T suppressor factors (TsF) described by different authors are indeed equivalent. This paper investigates whether monoclonal TsF3, obtained from hybridomas derived from mice injected subcutaneously with NP derived spleen cells, is functionally equivalent to the conventional T suppressor factor, produced by mice injected intravenously with chemically reactive, water soluble haptene (picrylsulphonic acid and oxazolone thioglycolic acid). Comparison of monoclonal anti-NP TsF3 with conventional anti-picryl and anti-oxazolone T suppressor factor showed that both armed the non-specific T acceptor cell (Tacc) which was sensitive to cyclophosphamide and adult thymectomy. Moreover, non-specific inhibitor (nsINH) of the transfer of contact sensitivity was released when antigen, together with major histocompatibility complex products (MHC), reacted with conventional or monoclonal TsF on the surface of the non-specific T acceptor cell. The interaction of monoclonal TsF3 with antigen, which led to the release of NsINH, required the presence of MHC and was I-J restricted. However, there was no Igh-1 restriction. The equivalence of conventional anti-picryl and anti-oxazolone TsF has been demonstrated by arming the Tacc with a mixture of these two suppressor factors, and then triggering the release of nsINH with the mixed haptene 'picryl-oxazolone-lysine' which crosslinks separate molecules of TsF. A similar equivalence of conventional anti-oxazolone TsF and monoclonal anti-NP TsF3 was demonstrated using the mixed hapten 'NP-oxazolone-lysine' to trigger the release of nsINH. It was concluded that monoclonal TsF3 and conventional TsF were equivalent, and that both had an indirect mode of action through the non-specific T acceptor cell which led to the production of non-specific inhibitor. PMID:6333385

  10. Controlling the Electrostatic Discharge Ignition Sensitivity of Composite Energetic Materials Using Carbon Nanotube Additives

    SciTech Connect

    Kade H. Poper; Eric S. Collins; Michelle L. Pantoya; Michael Daniels

    2014-10-01

    Powder energetic materials are highly sensitive to electrostatic discharge (ESD) ignition. This study shows that small concentrations of carbon nanotubes (CNT) added to the highly reactive mixture of aluminum and copper oxide (Al + CuO) significantly reduces ESD ignition sensitivity. CNT act as a conduit for electric energy, bypassing energy buildup and desensitizing the mixture to ESD ignition. The lowest CNT concentration needed to desensitize ignition is 3.8 vol.% corresponding to percolation corresponding to an electrical conductivity of 0.04 S/cm. Conversely, added CNT increased Al + CuO thermal ignition sensitivity to a hot wire igniter.

  11. Sensitivity of WallDYN material migration modeling to uncertainties in mixed-material surface binding energies

    DOE PAGES

    Nichols, J. H.; Jaworski, M. A.; Schmid, K.

    2017-03-09

    The WallDYN package has recently been applied to a number of tokamaks to self-consistently model the evolution of mixed-material plasma facing surfaces. A key component of the WallDYN model is the concentration-dependent surface sputtering rate, calculated using SDTRIM.SP. This modeled sputtering rate is strongly influenced by the surface binding energies (SBEs) of the constituent materials, which are well known for pure elements but often are poorly constrained for mixed-materials. This work examines the sensitivity of WallDYN surface evolution calculations to different models for mixed-material SBEs, focusing on the carbon/lithium/oxygen/deuterium system present in NSTX. A realistic plasma background is reconstructed frommore » a high density, H-mode NSTX discharge, featuring an attached outer strike point with local density and temperature of 4 × 1020 m-3 and 4 eV, respectively. It is found that various mixed-material SBE models lead to significant qualitative and quantitative changes in the surface evolution profile at the outer divertor, with the highest leverage parameter being the C-Li binding model. Uncertainties of order 50%, appearing on time scales relevant to tokamak experiments, highlight the importance of choosing an appropriate mixed-material sputtering representation when modeling the surface evolution of plasma facing components. Lastly, these results are generalized to other fusion-relevant materials with different ranges of SBEs.« less

  12. Permeation tests of glove and clothing materials against sensitizing chemicals using diphenylmethane diisocyanate as an example.

    PubMed

    Mäkelä, Erja A; Henriks-Eckerman, Maj-Len; Ylinen, Katriina; Vuokko, Aki; Suuronen, Katri

    2014-08-01

    Diphenylmethane diisocyanate (MDI) is a sensitizing chemical that can cause allergic contact dermatitis and asthma. Protective gloves and clothing are necessary to prevent skin exposure. Breakthrough times are used for the selection of chemical protective gloves and clothing. In the EN 374-3:2003 European standard, breakthrough time is defined as the time in which the permeation reaches the rate of 1.0 µg min(-1) cm(-2) through the material. Such breakthrough times do not necessarily represent safe limits for sensitizing chemicals. We studied the permeation of 4,4'-MDI through eight glove materials and one clothing material. The test method was derived from the EN 374-3 and ASTM F 739 standards. All measured permeation rates were below 0.1 µg min(-1) cm(-2), and thus, the breakthrough times for all the tested materials were over 480min, when the definitions of EN 374-3 and ASTM F 739 for the breakthrough time were used. Based on the sensitizing capacity of MDI, we concluded that a cumulative permeation of 1.0 µg cm(-2) should be used as the end point of the breakthrough time determination for materials used for protection against direct contact with MDI. Using this criterion for the breakthrough time, seven tested materials were permeated in <480min (range: 23-406min). Affordable chemical protective glove materials that had a breakthrough time of over 75min were natural rubber, thick polyvinylchloride, neoprene-natural rubber, and thin and thick nitrile rubber. We suggest that the current definitions of breakthrough times in the standard requirements for protective materials should be critically evaluated as regards MDI and other sensitizing chemicals, or chemicals highly toxic via the skin. © The Author 2014. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  13. The interactive effects of pH, surface tension, and solution density for flotation systems for separation of equivalent-density materials: separation of ABS from HIPS

    SciTech Connect

    Karvelas, D.E.; Jody, B.J.; Pomykala, J.A.; Daniels, E.J.

    1996-07-01

    This paper presents the results of research being conducted at Argonne National Laboratory, to develop a cost-effective and environmentally acceptable process for the separation of high-value plastics from discarded household appliances. The process under development has separated high-purity (greater than 99.5%) acrylonitrile-butadiene-styrene (ABS) and high-impact polystyrene (HIPS) from commingled plastics generated by appliance-shredding and metal recovery operations. Plastics of similar densities, such as ABS and HIPS are further separated by using a chemical solution. By controlling the surface tension, the density and the temperature of the chemical solution, we are able to selectively float/separate plastics that have equivalent densities. In laboratory-scale tests, this technique has proven highly effective in recovering high-purity plastics materials from discarded household appliances and other obsolete durable goods. A pilot plant is under construction to demonstrate and assess the technical and economic performance of this process. In this paper, we examine the technical and economic issues that affect the recovery and separation of plastics and provide an update on Argonne`s plastics separation research and development activities.

  14. Evaluation on mass sensitivity of SAW sensors for different piezoelectric materials using finite-element analysis.

    PubMed

    Abdollahi, Amir; Jiang, Zhongwei; Arabshahi, Sayyed Alireza

    2007-12-01

    The mass sensitivity of the piezoelectric surface acoustic wave (SAW) sensors is an important factor in the selection of the best gravimetric sensors for different applications. To determine this value without facing the practical problems and the long theoretical calculation time, we have shown that the mass sensitivity of SAW sensors can be calculated by a simple three-dimensional (3-D) finite-element analysis (FEA) using a commercial finite-element platform. The FEA data are used to calculate the wave propagation speed, surface particle displacements, and wave energy distribution on different cuts of various piezoelectric materials. The results are used to provide a simple method for evaluation of their mass sensitivities. Meanwhile, to calculate more accurate results from FEA data, surface and bulk wave reflection problems are considered in the analyses. In this research, different cuts of lithium niobate, quartz, lithium tantalate, and langasite piezoelectric materials are applied to investigate their acoustic wave properties. Our analyses results for these materials have a good agreement with other researchers' results. Also, the mass sensitivity value for the novel cut of langasite was calculated through these analyses. It was found that its mass sensitivity is higher than that of the conventional Rayleigh mode quartz sensor.

  15. Materials Testing in Long Cane Design: Sensitivity, Flexibility, and Transmission of Vibration

    ERIC Educational Resources Information Center

    Rodgers, Mark D.; Emerson, Robert Wall

    2005-01-01

    Different materials that are used in manufacturing long cane shafts were assessed for their ability to transmit vibration and their sensitivity to tactile information, flexibility, and durability. It was found that the less flexible a cane shaft is, the better it transmits vibrations that are useful for discriminating surface textures and that…

  16. High sensitivity spectroscopic and thermal characterization of cooling efficiency for optical refrigeration materials

    NASA Astrophysics Data System (ADS)

    Melgaard, Seth D.; Seletskiy, Denis V.; Di Lieto, Alberto; Tonelli, Mauro; Sheik-Bahae, Mansoor

    2012-03-01

    Since recent demonstration of cryogenic optical refrigeration, a need for reliable characterization tools of cooling performance of different materials is in high demand. We present our experimental apparatus that allows for temperature and wavelength dependent characterization of the materials' cooling efficiency and is based on highly sensitive spectral differencing technique or two-band differential spectral metrology (2B-DSM). First characterization of a 5% w.t. ytterbium-doped YLF crystal showed quantitative agreement with the current laser cooling model, as well as measured a minimum achievable temperature (MAT) at 110 K. Other materials and ion concentrations are also investigated and reported here.

  17. Angular sensitivity for a Fabry-Perot structure incorporating different dielectric materials

    NASA Astrophysics Data System (ADS)

    Wu, Shangliang; Ye, Yan; Zhou, Yun; Huang, Wenbin; Liu, Yanhua; Qiao, Wen; Wang, Yanyan; Luo, Minghui; Chen, Linsen

    2016-11-01

    Color filters based on different Fabry-Perot structures are investigated extensively, and incident angle dependency is an important characteristic in practical applications. Here, we investigated a color filter incorporating a Fabry-Perot structure, discussing its reflective angular sensitivity related to refractive index of its dielectric material. By finite difference time domain(FDTD) theory, the refractive index of the dielectric material is found to influence the angular sensitivity greatly while the optical thickness keeps constant. The simulated results shows that the higher the dielectric layer's refractive index is, the more angular insensitive of the reflection will be obtained and a good angular insensitive will achieved when the refractive index is larger than 2.1. Finally, samples with different dielectric layer are fabricated in experiment and the measured results verify influence of the refractive index of dielectric layer on the spectra angular sensitivity, which is helpful for the application of color filter in color display, image sensors and decoration.

  18. Technical Note: Radiation properties of tissue- and water-equivalent materials formulated using the stoichiometric analysis method in charged particle therapy

    SciTech Connect

    Yohannes, Indra; Vasiliniuc, Stefan; Hild, Sebastian; Langner, Oliver; Graeff, Christian; Bert, Christoph

    2016-01-15

    Purpose: Five tissue- and water-equivalent materials (TEMs) mimicking ICRU real tissues have been formulated using a previously established stoichiometric analysis method (SAM) to be applied in charged particle therapy. The purpose of this study was an experimental verification of the TEMs-SAM against charged particle beam measurements and for different computed tomography (CT) scanners. The potential of the TEMs-SAM to be employed in the dosimetry was also investigated. Methods: Experimental verification with three CT scanners was carried out to validate the calculated Hounsfield units (HUs) of the TEMs. Water-equivalent path lengths (WEPLs) of the TEMs for proton (106.8 MeV/u), helium (107.93 MeV/u), and carbon (200.3 MeV/u) ions were measured to be compared with the computed relative stopping powers. HU calibration curves were also generated. Results: Differences between the measured HUs of the TEMs and the calculated HUs of the ICRU real tissues for all CT scanners were smaller than 4 HU except for the skeletal tissues which deviated up to 21 HU. The measured WEPLs verified the calculated WEPLs of the TEMs (maximum deviation was 0.17 mm) and were in good agreement with the calculated WEPLs of the ICRU real tissues (maximum deviation was 0.23 mm). Moreover, the relative stopping powers converted from the measured WEPLs differed less than 0.8% and 1.3% from the calculated values of the SAM and the ICRU, respectively. Regarding the relative nonelastic cross section per unit of volume for 200 MeV protons, the ICRU real tissues were generally well represented by the TEMs except for adipose which differed 3.8%. Further, the HU calibration curves yielded the mean and the standard deviation of the errors not larger than 0.5% and 1.9%, respectively. Conclusions: The results of this investigation implied the potential of the TEMs formulated using the SAM to be employed for both, beam dosimetry and HU calibration in charged particle therapy.

  19. Substrate-anchored and degradation-sensitive anti-inflammatory coatings for implant materials

    NASA Astrophysics Data System (ADS)

    Wu, Duo; Chen, Xingyu; Chen, Tianchan; Ding, Chunmei; Wu, Wei; Li, Jianshu

    2015-06-01

    Implant materials need to be highly biocompatible to avoid inflammation in clinical practice. Although biodegradable polymeric implants can eliminate the need for a second surgical intervention to remove the implant materials, they may produce acidic degradation products in vivo and cause non-bacterial inflammation. Here we show the strategy of “substrate-anchored and degradation-sensitive coatings” for biodegradable implants. Using poly(lactic acid)/hydroxyapatite as an implant material model, we constructed a layer-by-layer coating using pH-sensitive star polymers and dendrimers loaded with an anti-inflammatory drug, which was immobilised through a hydroxyapatite-anchored layer. The multifunctional coating can effectively suppress the local inflammation caused by the degradation of implant materials for at least 8 weeks in vivo. Moreover, the substrate-anchored coating is able to modulate the degradation of the substrate in a more homogeneous manner. The “substrate-anchored and degradation-sensitive coating” strategy therefore exhibits potential for the design of various self-anti-inflammatory biodegradable implant materials.

  20. Sensitivity on materials optical properties of single beam torsional Casimir actuation

    NASA Astrophysics Data System (ADS)

    Tajik, Fatemeh; Sedighi, Mehdi; Palasantzas, George

    2017-05-01

    Here, we investigate the dynamical sensitivity of electrostatic torsional type microelectromechanical systems (MEMS) on the optical properties of interacting materials. This is accomplished by considering the combined effect of mechanical Casimir and electrostatic torques to drive the device actuation. The bifurcation curves and the phase portraits of the actuation dynamics have been analyzed to compare the sensitivity of a single beam torsional device operating between materials with conductivities that differ by several orders of magnitude. It is shown that the range of stable operation of torsional MEMS against stiction instabilities can increase by decreasing the conductivity of interacting materials. Moreover, the introduction of controlled dissipation, corresponding to a finite quality factor, in an otherwise unstable torsional system, could alter an unstable motion towards stiction to dissipative stable motion.

  1. High sensitivity piezomagnetic force microscopy for quantitative probing of magnetic materials at the nanoscale.

    PubMed

    Chen, Qian Nataly; Ma, Feiyue; Xie, Shuhong; Liu, Yuanming; Proksch, Roger; Li, Jiangyu

    2013-07-07

    Accurate scanning probing of magnetic materials at the nanoscale is essential for developing and characterizing magnetic nanostructures, yet quantitative analysis is difficult using the state of the art magnetic force microscopy, and has limited spatial resolution and sensitivity. In this communication, we develop a novel piezomagnetic force microscopy (PmFM) technique, with the imaging principle based on the detection of magnetostrictive response excited by an external magnetic field. In combination with the dual AC resonance tracking (DART) technique, the contact stiffness and energy dissipation of the samples can be simultaneously mapped along with the PmFM phase and amplitude, enabling quantitative probing of magnetic materials and structures at the nanoscale with high sensitivity and spatial resolution. PmFM has been applied to probe magnetic soft discs and cobalt ferrite thin films, demonstrating it as a powerful tool for a wide range of magnetic materials.

  2. Implementation of strain rate sensitive material properties into impact related problems

    SciTech Connect

    Laubscher, R.F.; Merwe, P. van der

    1995-12-31

    Strain rate sensitivity is discussed in general. A general strain rate sensitive constitutive model is then derived with a yield criterion for an isotropic hardening material incorporating a modified version of the Cowper Symonds equation. Experimental data for 10 different metals ranging from carbon steels to titanium alloys are fitted to this constitutive model. It is shown that with this relatively simple model a good agreement can be achieved between the constitutive model and the experimental data for most metals. The manner in which this constitutive model may be used in design is discussed along with its incorporation into numerical methods such as finite elements.

  3. Development of High-Sensitivity Ultrasonic Transducer in Air with Nanofoam Material

    NASA Astrophysics Data System (ADS)

    Nagahara, Hidetomo; Hashida, Takashi; Suzuki, Masa-aki; Hashimoto, Masahiko

    2005-06-01

    For a high-sensitivity ultrasonic transducer in air, it was considered that nanofoam be applied to its acoustic matching layer. Nanofoam is a porous material that is made by the sol-gel process. Since nanofoam has an extremely low acoustic impedance, it is effective for the acoustic matching layer of an ultrasonic transducer in air. In this study, we have fabricated an ultrasonic transducer that had two acoustic matching layers and estimated its acoustic properties. The two matching layers were made of silica nanofoam and porous ceramic. The sensitivity of the developed ultrasonic transducer was about twenty times higher than that of a conventional ultrasonic transducer in air.

  4. Plutonium 239 Equivalency Calculations

    SciTech Connect

    Wen, J

    2011-05-31

    This document provides the basis for converting actual weapons grade plutonium mass to a plutonium equivalency (PuE) mass of Plutonium 239. The conversion can be accomplished by performing calculations utilizing either: (1) Isotopic conversions factors (CF{sub isotope}), or (2) 30-year-old weapons grade conversion factor (CF{sub 30 yr}) Both of these methods are provided in this document. Material mass and isotopic data are needed to calculate PuE using the isotopic conversion factors, which will provide the actual PuE value at the time of calculation. PuE is the summation of the isotopic masses times their associated isotopic conversion factors for plutonium 239. Isotopic conversion factors are calculated by a normalized equation, relative to Plutonium 239, of specific activity (SA) and cumulated dose inhalation affects based on 50-yr committed effective dose equivalent (CEDE). The isotopic conversion factors for converting weapons grade plutonium to PuE are provided in Table-1. The unit for specific activity (SA) is curies per gram (Ci/g) and the isotopic SA values come from reference [1]. The cumulated dose inhalation effect values in units of rem/Ci are based on 50-yr committed effective dose equivalent (CEDE). A person irradiated by gamma radiation outside the body will receive a dose only during the period of irradiation. However, following an intake by inhalation, some radionuclides persist in the body and irradiate the various tissues for many years. There are three groups CEDE data representing lengths of time of 0.5 (D), 50 (W) and 500 (Y) days, which are in reference [2]. The CEDE values in the (W) group demonstrates the highest dose equivalent value; therefore they are used for the calculation.

  5. Laser Ablation/Ionisation Mass Spectrometry: Sensitive and Quantitative Chemical Depth Profiling of Solid Materials.

    PubMed

    Riedo, Andreas; Grimaudo, Valentine; Moreno-García, Pavel; Neuland, Maike B; Tulej, Marek; Broekmann, Peter; Wurz, Peter

    2016-01-01

    Direct quantitative and sensitive chemical analysis of solid materials with high spatial resolution, both in lateral and vertical direction is of high importance in various fields of analytical research, ranging from in situ space research to the semiconductor industry. Accurate knowledge of the chemical composition of solid materials allows a better understanding of physical and chemical processes that formed/altered the material and allows e.g. to further improve these processes. So far, state-of-the-art techniques such as SIMS, LA-ICP-MS or GD-MS have been applied for chemical analyses in these fields of research. In this report we review the current measurement capability and the applicability of our Laser Ablation/Ionisation Mass Spectrometer (instrument name LMS) for the chemical analysis of solids with high spatial resolution. The most recent chemical analyses conducted on various solid materials, including e.g. alloys, fossils and meteorites are discussed.

  6. 46 CFR 133.09 - Equivalents.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Equivalents. When this part requires a particular fitting, material, or lifesaving appliance or arrangement, the Commandant (CG-521) may accept any other fitting, material, or lifesaving appliance or arrangement... evaluations and tests to determine the equivalent effectiveness of the substitute fitting, material,...

  7. Printable microfluidic systems using pressure sensitive adhesive material for biosensing devices.

    PubMed

    Wang, Xin; Nilsson, David; Norberg, Petronella

    2013-09-01

    In biosensors with a fluid analyte, the integration of a microfluidic system, which guides the analyte into the sensing area, is critical. Quicker and economical ways to build up microfluidic systems will make point of care diagnostics viable. Printing is a low-cost technology that is increasingly used in emerging organic and flexible electronics and biosensors. In this paper, we present printed fluidic systems on flexible substrates made with pressure sensitive adhesive materials. Printable pressure sensitive adhesive materials have been used for making microfluidic systems. Flexible substrates have been used, and two types of adhesive materials, one thermally dried and another UV curable, have been tested. Top sealing layer was laminated directly on top of the printed microfluidic structure. Flow tests were done with deionized water. Flow tests with deionized water show that both adhesive materials are suitable for capillary flow driven fluidic devices. Flow test using water as dielectric material was also done successfully on a printed electrolyte gated organic field effect transistor with an integrated microfluidic system. Due to its ease of process and low cost, printed microfluidic system is believed to find more applications in biosensing devices. This article is part of a Special Issue entitled Organic Bioelectronics-Novel Applications in Biomedicine. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Nematodes as Sensitive Indicators of Change at Dredged Material Disposal Sites

    NASA Astrophysics Data System (ADS)

    Boyd, S. E.; Rees, H. L.; Richardson, C. A.

    2000-12-01

    Demonstration of the recovery of marine habitats from perturbation, or of the effectiveness of protective measures, is dependent on the sensitivity of the target group in responding to change. This paper highlights the utility of the nematode component of the meiofauna as a tool for assessing disturbance from dredgings disposal. Transect surveys were conducted at three major dredged material disposal sites around the U.K. coast. Both gross effects due to the direct impact of dredgings within the disposal sites and lesser consequences arising from the transport of material away from the sites were evident with nematode community analyses. The same nematode species, Sabatieria pulchra group (both breviseta and punctata ) and Daptonema tenuispiculum were found to dominate at all disposal sites, despite appreciable environmental differences between locations and variability in the nature of the deposited dredged material. These studies have established that nematode communities can provide a sensitive indicator of change in response to dredged material disposal at a variety of locations and have introduced a new monitoring tool for a practice that has a wide significance around the U.K. coast. The implications of the findings for the future monitoring of dredged material disposal and other waste inputs are discussed.

  9. Mechanical behavior of a fluid-sensitive material during liquid diffusion

    NASA Astrophysics Data System (ADS)

    Widiastuti, Indah; Sbarski, Igor; Masood, S. H.

    2014-05-01

    This paper described the analytical study that we performed in an attempt to understand the combined effect of liquid diffusion and temperature on the mechanical response of viscoelastic liquid-sensitive material. A constitutive equation for linear viscoelasticity, which includes the effect of liquid diffusion, is used to model the mechanical response of a fluid-sensitive polymer such as PLA-based bioplastic. The viscoelastic characteristics which represent material degradation due to liquid diffusion were expressed using a creep-based formulation represented by Burger's model. Creep experiment data were fitted to the Burgers model to provide a liquid content-dependent set of input data for subsequent time-dependent analysis. Further, analytical solutions for stresses and deformations were obtained from the corresponding elastic solution by applying the Correspondence Principle, using previously defined material characteristics. Spatial and time variations of stress and deformation were evaluated to give a precise description of the material behavior under hygroscopic conditions. We propose a stress concentration factor to take into account the liquid diffusion-induced stress that may result in a failure of an application. The results emphasize the importance of considering liquid diffusion and viscoelastic properties in the design of components using liquid-absorbable material.

  10. Single-crystalline zinc oxide nanowires as photoanode material for dye-sensitized solar cells.

    PubMed

    Ho, Shu-Te; Hsiao, Ching-Lun; Lin, Hsin-Yu; Chen, Hsiang-An; Wang, Chiu-Yen; Lin, Heh-Nan

    2010-10-01

    This study reports the use of single-crystalline and well-aligned ZnO nanowires as photoanode material for dye-sensitized solar cells. The ZnO nanowires are grown on fluorine-doped tin oxide coated glass substrates without catalysts by thermal evaporation. In spite of low roughness factors of around 25 for the nanowire photoanodes, the fabricated solar cells yield power conversion efficiencies of around 1.3% under AM 1.5G (100 mW cm-2) illumination. Moreover, fill factors of around 0.5 have been achieved and are relatively high when compared with reported values from ZnO nanowire photoanodes. The results reveal the advantage of using single-crystalline nanowires as photoanode material and provide clues for the advancement of nanowire based dye-sensitized solar cells.

  11. Sensitive and absolute absorption measurements in optical materials and coatings by laser-induced deflection technique

    NASA Astrophysics Data System (ADS)

    Mühlig, Christian; Bublitz, Simon

    2012-12-01

    The laser-induced deflection (LID) technique, a photo-thermal deflection setup with transversal pump-probe-beam arrangement, is applied for sensitive and absolute absorption measurements of optical materials and coatings. Different LID concepts for bulk and transparent coating absorption measurements, respectively, are explained, focusing on providing accurate absorption data with only one measurement and one sample. Furthermore, a new sandwich concept is introduced that allows transferring the LID technique to very small sample geometries and to significantly increase the sensitivity for materials with weak photo-thermal responses. For each of the different concepts, a representative application example is given. Particular emphasis is placed on the importance of the calibration procedure for providing absolute absorption data. The validity of an electrical calibration procedure for the LID setup is proven using specially engineered surface absorbing samples. The electrical calibration procedure is then applied to evaluate two other approaches that use either doped samples or highly absorptive reference samples.

  12. Impact sensitivities of energetic materials: Exploring the limitations of a model based only on structural formulas.

    PubMed

    Mathieu, Didier; Alaime, Thibaud

    2015-11-01

    Using a comprehensive set of drop weight impact test data (h50) newly compiled from literature for 308 materials, a recent approach to predict impact sensitivities of nitro compounds is generalized to most explosive substances of interest. Compared to previous ones, this procedure is more thoroughly validated and exhibits a good predictive value. Furthermore, it yields new insight into the physical mechanisms involved, explaining for instance the unexpected desensitization of some oxygen-deficient triazoles upon nitration.

  13. Sensitivity of Material Response Calculations to the Equation of State Model

    DTIC Science & Technology

    equation of state model. Three equation of state models, all...sources. The sensitivity of the calculated material response to the choice of equation of state model is characterized in terms of the generated impulse...and the peak propagating stress at the time the radiation source is cut off. For the calculations presented in this report, the three equation of state models are in fairly good

  14. Sensitivity of the Boundary Plasma to the Plasma-Material Interface

    SciTech Connect

    Canik, John M.; Tang, X. -Z.

    2017-01-01

    While the sensitivity of the scrape-off layer and divertor plasma to the highly uncertain cross-field transport assumptions is widely recognized, the plasma is also sensitive to the details of the plasma-material interface (PMI) models used as part of comprehensive predictive simulations. Here in this paper, these PMI sensitivities are studied by varying the relevant sub-models within the SOLPS plasma transport code. Two aspects are explored: the sheath model used as a boundary condition in SOLPS, and fast particle reflection rates for ions impinging on a material surface. Both of these have been the study of recent high-fidelity simulation efforts aimed at improving the understanding and prediction of these phenomena. It is found that in both cases quantitative changes to the plasma solution result from modification of the PMI model, with a larger impact in the case of the reflection coefficient variation. Finally, this indicates the necessity to better quantify the uncertainties within the PMI models themselves, and perform thorough sensitivity analysis to propagate these throughout the boundary model; this is especially important for validation against experiment, where the error in the simulation is a critical and less-studied piece of the code-experiment comparison.

  15. Sensitivity of the Boundary Plasma to the Plasma-Material Interface

    DOE PAGES

    Canik, John M.; Tang, X. -Z.

    2017-01-01

    While the sensitivity of the scrape-off layer and divertor plasma to the highly uncertain cross-field transport assumptions is widely recognized, the plasma is also sensitive to the details of the plasma-material interface (PMI) models used as part of comprehensive predictive simulations. Here in this paper, these PMI sensitivities are studied by varying the relevant sub-models within the SOLPS plasma transport code. Two aspects are explored: the sheath model used as a boundary condition in SOLPS, and fast particle reflection rates for ions impinging on a material surface. Both of these have been the study of recent high-fidelity simulation efforts aimedmore » at improving the understanding and prediction of these phenomena. It is found that in both cases quantitative changes to the plasma solution result from modification of the PMI model, with a larger impact in the case of the reflection coefficient variation. Finally, this indicates the necessity to better quantify the uncertainties within the PMI models themselves, and perform thorough sensitivity analysis to propagate these throughout the boundary model; this is especially important for validation against experiment, where the error in the simulation is a critical and less-studied piece of the code-experiment comparison.« less

  16. Sensitivity Characterization of Pressed Energetic Materials using Flyer Plate Mesoscale Simulations

    NASA Astrophysics Data System (ADS)

    Rai, Nirmal; Udaykumar, H. S.

    Heterogeneous energetic materials like pressed explosives have complicated microstructure and contain various forms of heterogeneities such as pores, micro-cracks, energetic crystals etc. It is widely accepted that the presence of these heterogeneities can affect the sensitivity of these materials under shock load. The interaction of shock load with the microstructural heterogeneities may leads to the formation of local heated regions known as ``hot spots''. Chemical reaction may trigger at the hot spot regions depending on the hot spot temperature and the duration over which the temperature can be maintained before phenomenon like heat conduction, rarefaction waves withdraws energy from it. There are different mechanisms which can lead to the formation of hot spots including void collapse. The current work is focused towards the sensitivity characterization of two HMX based pressed energetic materials using flyer plate mesoscale simulations. The aim of the current work is to develop mesoscale numerical framework which can perform simulations by replicating the laboratory based flyer plate experiments. The current numerical framework uses an image processing approach to represent the microstructural heterogeneities incorporated in a massively parallel Eulerian code SCIMITAR3D. The chemical decomposition of HMX is modeled using Henson-Smilowitz reaction mechanism. The sensitivity characterization is aimed towards obtaining James initiation threshold curve and comparing it with the experimental results.

  17. Fiber-based lensless polarization holography for measuring Jones matrix parameters of polarization-sensitive materials.

    PubMed

    Liu, Xuan; Yang, Yang; Han, Lu; Guo, Cheng-Shan

    2017-04-03

    We report a fiber-based lensless holographic imaging system to realize a single-shot measurement of two dimensional (2-D) Jones matrix parameters of polarization-sensitive materials. In this system, a multi-source lensless off-axis Fresnel holographic recording geometry is adopted, and two optical fiber splitters are used to generate the multiple reference and illumination beams required for recording a four-channel angular-multiplexing polarization hologram (AMPH). Using this system and the method described in this paper, spatially resolved Jones matrix parameters of a polarization-sensitive material can be retrieved from one single-shot AMPH. We demonstrate the feasibility of the method by extracting a 2-D Jones matrix of a composite polarizer. Applications of the method to measure the Jones matrix maps of a stressed polymethyl methacrylate sample and a mica fragment are also presented. Benefit from the fiber-based and lensless off-axis holographic design, the system possesses a quite compact configuration, which provides a feasible approach for development of an integrated and portable system to measure Jones matrix parameters of polarization-sensitive materials.

  18. Effect of electrode material and design on sensitivity and selectivity for high temperature impedancemetric NOx sensors

    SciTech Connect

    Woo, L Y; Glass, R S; Novak, R F; Visser, J H

    2009-09-23

    Solid-state electrochemical sensors using two different sensing electrode compositions, gold and strontium-doped lanthanum manganite (LSM), were evaluated for gas phase sensing of NO{sub x} (NO and NO{sub 2}) using an impedance-metric technique. An asymmetric cell design utilizing porous YSZ electrolyte exposed both electrodes to the test gas (i.e., no reference gas). Sensitivity to less than 5 ppm NO and response/recovery times (10-90%) less than 10 s were demonstrated. Using an LSM sensing electrode, virtual identical sensitivity towards NO and NO{sub 2} was obtained, indicating that the equilibrium gas concentration was measured by the sensing electrode. In contrast, for cells employing a gold sensing electrode the NO{sub x} sensitivity varied depending on the cell design: increasing the amount of porous YSZ electrolyte on the sensor surface produced higher NO{sub 2} sensitivity compared to NO. In order to achieve comparable sensitivity for both NO and NO{sub 2}, the cell with the LSM sensing electrode required operation at a lower temperature (575 C) than the cell with the gold sensing electrode (650 C). The role of surface reactions are proposed to explain the differences in NO and NO{sub 2} selectivity using the two different electrode materials.

  19. High pressure liquid and gaseous oxygen impact sensitivity evaluation of materials for use at Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    Bryan, C. J.

    1976-01-01

    The sensitivity of materials in contact with gaseous oxygen (GOX) or liquid oxygen (LOX) was examined. Specifically, the reactivity of materials when in contact with GOX or LOX if subjected to such stimuli as mechanical impact, adiabatic compression (pneumatic impact), or an electrical discharge in the form of a spark were examined. Generally, materials are more sensitive in gaseous oxygen than in liquid oxygen and impact sensitivity is known to increase with increasing pressure. Materials presently being used or considered for use in oxygen systems at KSC were evaluated. Results are given in tabular form.

  20. Comments on TNT Equivalence

    SciTech Connect

    Cooper, P.W.

    1994-07-01

    The term ``TNT Equivalence`` is used throughout the explosives and related industries to compare the effects of the output of a given explosive to that of TNT. This is done for technical design reasons in scaling calculation such as for the prediction of blast waves, craters, and structural response, and is also used as a basis for government regulations controlling the shipping, handling and storage of explosive materials, as well as for the siting and design of explosive facilities. TNT equivalence is determined experimentally by several different types of tests, the most common of which include: plate dent, ballistic mortar, trauzl, sand crush, and air blast. All of these tests do not necessarily measure the same output property of the sample explosive. As examples of this, some tests depend simply upon the CJ pressure, some depend upon the PV work in the CJ zone and in the Taylor wave behind the CJ plane, some are functions of the total work which includes that from secondary combustion in the air mixing region of the fireball and are acutely effected by the shape of the pressure-time profile of the wave. Some of the tests incorporate systematic errors which are not readily apparent, and which have a profound effect upon skewing the resultant data. Further, some of the tests produce different TNT Equivalents for the same explosive which are a function of the conditions at which the test is run. This paper describes the various tests used, discusses the results of each test and makes detailed commentary on what the test is actually measuring, how the results may be interpreted, and if and how these results can be predicted by first principals based calculations. Extensive data bases are referred to throughout the paper and used in examples for each point in the commentaries.

  1. Study on photon sensitivity of silicon diodes related to materials used for shielding

    NASA Astrophysics Data System (ADS)

    Moiseev, T.

    1999-08-01

    Large area silicon diodes used in electronic neutron dosemeters have a significant over-response to X- and gamma-rays, highly non-linear at photon energies below 200 keV. This over-response to photons is proportional to the diode's active area and strongly affects the neutron sensitivity of such dosemeters. Since silicon diodes are sensitive to light and electromagnetic fields, most diode detector assemblies are provided with a shielding, sometimes also used as radiation filter. In this paper, the influence of materials covering the diode's active area is investigated using the MCNP-4A code by estimating the photon induced pulses in a typical silicon wafer (300 μm thickness and 1 cm diameter) when provided with a front case cover. There have been simulated small-size diode front covers made of several materials with low neutron interaction cross-sections like aluminium, TEFLON, iron and lead. The estimated number of induced pulses in the silicon wafer is calculated for each type of shielding at normal photon incidence for several photon energies from 9.8 keV up to 1.15 MeV and compared with that in a bare silicon wafer. The simulated pulse height spectra show the origin of the photon-induced pulses in silicon for each material used as protective cover: the photoelectric effect for low Z front case materials at low-energy incident photons (up to about 65 keV) and the Compton and build-up effects for high Z case materials at higher photon energies. A simple means to lower and flatten the photon response of silicon diodes over an extended X- and gamma rays energy range is proposed by designing a composed photon filter.

  2. New composite blue sensitive materials for high resolution optical data storage

    NASA Astrophysics Data System (ADS)

    Criante, L.; Castagna, R.; Vita, F.; Lucchetta, D. E.; Simoni, F.; Frohmann, S.; Feid, T.; Orlic, S.

    2007-09-01

    In the last three decades several kinds of organic mixtures for holographic recording were developed in order to achieve a new class of DVD-like optical memories for high-density optical data storage. The holographic materials should satisfy the following requirements: high sensitivity to blue light, low losses, high spatial resolution and long term stability. To this aim we developed new organic photosensitive mixtures based on only three components. We recorded high spatial frequency reflection gratings up to 7400 lines/mm with blue laser light (405 nm) by using a conventional holographic setup. We obtained a macro grating diffraction efficiency up to 67%, refractive index modulation over 0.01, optical shrinkage < 2 % and overall losses ~5%. In order to characterize data-storage materials independently on the experimental conditions, the sensitivity has been evaluated through the S parameter which takes into account the diffraction efficiency, recording light intensity, exposure time and sample thickness. The amazing obtained values of S >10 5 cm/J evidences a very fast recording process with a very low writing intensity (less than 20 mW/cm2) corresponding to a recording energy density of few mJ/cm2. The performance of these materials have been also tested in the microholographic geometry.

  3. Highly sensitive molecular diagnosis of prostate cancer using surplus material washed off from biopsy needles

    PubMed Central

    Bermudo, R; Abia, D; Mozos, A; García-Cruz, E; Alcaraz, A; Ortiz, Á R; Thomson, T M; Fernández, P L

    2011-01-01

    Introduction: Currently, final diagnosis of prostate cancer (PCa) is based on histopathological analysis of needle biopsies, but this process often bears uncertainties due to small sample size, tumour focality and pathologist's subjective assessment. Methods: Prostate cancer diagnostic signatures were generated by applying linear discriminant analysis to microarray and real-time RT–PCR (qRT–PCR) data from normal and tumoural prostate tissue samples. Additionally, after removal of biopsy tissues, material washed off from transrectal biopsy needles was used for molecular profiling and discriminant analysis. Results: Linear discriminant analysis applied to microarray data for a set of 318 genes differentially expressed between non-tumoural and tumoural prostate samples produced 26 gene signatures, which classified the 84 samples used with 100% accuracy. To identify signatures potentially useful for the diagnosis of prostate biopsies, surplus material washed off from routine biopsy needles from 53 patients was used to generate qRT–PCR data for a subset of 11 genes. This analysis identified a six-gene signature that correctly assigned the biopsies as benign or tumoural in 92.6% of the cases, with 88.8% sensitivity and 96.1% specificity. Conclusion: Surplus material from prostate needle biopsies can be used for minimal-size gene signature analysis for sensitive and accurate discrimination between non-tumoural and tumoural prostates, without interference with current diagnostic procedures. This approach could be a useful adjunct to current procedures in PCa diagnosis. PMID:22009027

  4. Highly sensitive molecular diagnosis of prostate cancer using surplus material washed off from biopsy needles.

    PubMed

    Bermudo, R; Abia, D; Mozos, A; García-Cruz, E; Alcaraz, A; Ortiz, A R; Thomson, T M; Fernández, P L

    2011-11-08

    Currently, final diagnosis of prostate cancer (PCa) is based on histopathological analysis of needle biopsies, but this process often bears uncertainties due to small sample size, tumour focality and pathologist's subjective assessment. Prostate cancer diagnostic signatures were generated by applying linear discriminant analysis to microarray and real-time RT-PCR (qRT-PCR) data from normal and tumoural prostate tissue samples. Additionally, after removal of biopsy tissues, material washed off from transrectal biopsy needles was used for molecular profiling and discriminant analysis. Linear discriminant analysis applied to microarray data for a set of 318 genes differentially expressed between non-tumoural and tumoural prostate samples produced 26 gene signatures, which classified the 84 samples used with 100% accuracy. To identify signatures potentially useful for the diagnosis of prostate biopsies, surplus material washed off from routine biopsy needles from 53 patients was used to generate qRT-PCR data for a subset of 11 genes. This analysis identified a six-gene signature that correctly assigned the biopsies as benign or tumoural in 92.6% of the cases, with 88.8% sensitivity and 96.1% specificity. Surplus material from prostate needle biopsies can be used for minimal-size gene signature analysis for sensitive and accurate discrimination between non-tumoural and tumoural prostates, without interference with current diagnostic procedures. This approach could be a useful adjunct to current procedures in PCa diagnosis. 2011 Cancer Research UK

  5. Increased Throughput and Sensitivity of Synchrotron-Based Characterization for Photovoltaic Materials

    DOE PAGES

    Morishige, Ashley E.; Laine, Hannu S.; Looney, Erin E.; ...

    2017-04-03

    Optimizing photovoltaic (PV) devices requires characterization and optimization across several length scales, from centimeters to nanometers. Synchrotron-based micro-X-ray fluorescence spectromicroscopy (μ-XRF) is a valuable link in the PV-related material and device characterization suite. μ-XRF maps of elemental distributions in PV materials have high spatial resolution and excellent sensitivity and can be measured on absorber materials and full devices. Recently, we implemented on-the-fly data collection (flyscan) at Beamline 2-ID-D at the Advanced Photon Source at Argonne National Laboratory, eliminating a 300 ms per-pixel overhead time. This faster scanning enables high-sensitivity (~1014 atoms/cm2), large-area (10 000s of μm 2), high-spatial resolution (<;200more » nm scale) maps to be completed within a practical scanning time. We specifically show that when characterizing detrimental trace metal precipitate distributions in multicrystalline silicon wafers for PV, flyscans can increase the productivity of μ-XRF by an order of magnitude. Additionally, flyscan μ-XRF mapping enables relatively large-area correlative microscopy. As an example, we map the transition metal distribution in a 50 μm-diameter laser-fired contact of a silicon solar cell before and after lasing. As a result, while we focus on μ-XRF of mc-Si wafers for PV, our results apply broadly to synchrotron-based mapping of PV absorbers and devices.« less

  6. Sensitivity of acoustic nonlinearity parameter to the microstructural changes in cement-based materials

    NASA Astrophysics Data System (ADS)

    Kim, Gun; Kim, Jin-Yeon; Kurtis, Kimberly E.; Jacobs, Laurence J.

    2015-03-01

    This research experimentally investigates the sensitivity of the acoustic nonlinearity parameter to microcracks in cement-based materials. Based on the second harmonic generation (SHG) technique, an experimental setup using non-contact, air-coupled detection is used to receive the consistent Rayleigh surface waves. To induce variations in the extent of microscale cracking in two types of specimens (concrete and mortar), shrinkage reducing admixture (SRA), is used in one set, while a companion specimen is prepared without SRA. A 50 kHz wedge transducer and a 100 kHz air-coupled transducer are implemented for the generation and detection of nonlinear Rayleigh waves. It is shown that the air-coupled detection method provides more repeatable fundamental and second harmonic amplitudes of the propagating Rayleigh waves. The obtained amplitudes are then used to calculate the relative nonlinearity parameter βre, the ratio of the second harmonic amplitude to the square of the fundamental amplitude. The experimental results clearly demonstrate that the nonlinearity parameter (βre) is highly sensitive to the microstructural changes in cement-based materials than the Rayleigh phase velocity and attenuation and that SRA has great potential to avoid shrinkage cracking in cement-based materials.

  7. Damage sensitivity investigations of EMI technique on different materials through coupled field analysis

    NASA Astrophysics Data System (ADS)

    Joshi, Bhrigu; Adhikari, Sailesh; Bhalla, Suresh

    2016-04-01

    This paper presents a comparative study through the piezoelectric coupled field analysis mode of finite element method (FEM) on detection of damages of varying magnitude, encompassing three different types of structural materials, using piezo impedance transducers. An aluminum block, a concrete block and a steel block of dimensions 48×48×10 mm were modelled in finite element software ANSYS. A PZT patch of 10×10×0.3 mm was also included in the model as surface bonded on the block. Coupled field analysis (CFA) was performed to obtain the admittance signatures of the piezo sensor in the frequency range of 0-250 kHz. The root mean square deviation (RMSD) index was employed to quantify the degree of variation of the signatures. It was found that concrete exhibited deviation in the signatures only with the change of damping values. However, the other two materials showed variation in the signatures even with changes in density and elasticity values in a small portion of the specimen. The comparative study shows that the PZT patches are more sensitive to damage detection in materials with low damping and the sensitivity typically decreases with increase in the damping.

  8. Modeling materials and processes in dye-sensitized solar cells: understanding the mechanism, improving the efficiency.

    PubMed

    Pastore, Mariachiara; De Angelis, Filippo

    2014-01-01

    We present a review of recent first-principles computational modeling studies on dye-sensitized solar cells (DSCs), focusing on the materials and processes modeling aspects which are key to the functioning of this promising class of photovoltaic devices. Crucial to the DSCs functioning is the photoinduced charge separation occurring at the heterointerface(s) between a dye-sensitized nanocrystalline, mesoporous metal oxide electrode and a redox shuttle. Theoretical and computational modeling of isolated cell components (e.g., dye, semiconductor nanoparticles, redox shuttle, etc…) as well as of combined dye/semiconductor/redox shuttle systems can successfully assist the experimental research by providing basic design rules of new sensitizers and a deeper comprehension of the fundamental chemical and physical processes governing the cell functioning and its performances. A computational approach to DSCs modeling can essentially be cast into a stepwise problem, whereby one first needs to simulate accurately the individual DSCs components to move to relevant pair (or higher order) interactions characterizing the device functioning. This information can contribute to enhancing further the target DSCs characteristics, such as temporal stability and optimization of device components. After presenting selected results for isolated dyes, including the computational design of new dyes, and model semiconductors, including realistic nanostructure models, we focus in the remainder of this review on the interaction between dye-sensitizers and semiconductor oxides, covering organic as well as metallorganic dyes.

  9. Hollow graphitic nanocapsules as efficient electrode materials for sensitive hydrogen peroxide detection.

    PubMed

    Liu, Wei-Na; Ding, Ding; Song, Zhi-Ling; Bian, Xia; Nie, Xiang-Kun; Zhang, Xiao-Bing; Chen, Zhuo; Tan, Weihong

    2014-02-15

    Carbon nanomaterials are typically used in electrochemical biosensing applications for their unique properties. We report a hollow graphitic nanocapsule (HGN) utilized as an efficient electrode material for sensitive hydrogen peroxide detection. Methylene blue (MB) molecules could be efficiently adsorbed on the HGN surfaces, and this adsorption capability remained very stable under different pH regimes. HGNs were used as three-dimensional matrices for coimmobilization of MB electron mediators and horseradish peroxidase (HRP) to build an HGN-HRP-MB reagentless amperometric sensing platform to detect hydrogen peroxide. This simple HGN-HRP-MB complex demonstrated very sensitive and selective hydrogen peroxide detection capability, as well as high reproducibility and stability. The HGNs could also be utilized as matrices for immobilization of other enzymes, proteins or small molecules and for different biomedical applications. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Label-free and pH-sensitive colorimetric materials for the sensing of urea

    NASA Astrophysics Data System (ADS)

    Li, Lu; Long, Yue; Gao, Jin-Ming; Song, Kai; Yang, Guoqiang

    2016-02-01

    This communication demonstrates a facile method for naked-eye detection of urea based on the structure color change of pH-sensitive photonic crystals. The insertion of urease provides excellent selectivity over other molecules. The detection of urea in different concentration ranges could be realized by changing the molar ratio between the functional monomer and cross-linker.This communication demonstrates a facile method for naked-eye detection of urea based on the structure color change of pH-sensitive photonic crystals. The insertion of urease provides excellent selectivity over other molecules. The detection of urea in different concentration ranges could be realized by changing the molar ratio between the functional monomer and cross-linker. Electronic supplementary information (ESI) available: Materials and chemicals, characterization, experimental details, and SEM images. See DOI: 10.1039/c5nr07690k

  11. Sensitivity of hydrological performance assessment analysis to variations in material properties, conceptual models, and ventilation models

    SciTech Connect

    Sobolik, S.R.; Ho, C.K.; Dunn, E.; Robey, T.H.; Cruz, W.T.

    1996-07-01

    The Yucca Mountain Site Characterization Project is studying Yucca Mountain in southwestern Nevada as a potential site for a high-level nuclear waste repository. Site characterization includes surface- based and underground testing. Analyses have been performed to support the design of an Exploratory Studies Facility (ESF) and the design of the tests performed as part of the characterization process, in order to ascertain that they have minimal impact on the natural ability of the site to isolate waste. The information in this report pertains to sensitivity studies evaluating previous hydrological performance assessment analyses to variation in the material properties, conceptual models, and ventilation models, and the implications of this sensitivity on previous recommendations supporting ESF design. This document contains information that has been used in preparing recommendations for Appendix I of the Exploratory Studies Facility Design Requirements document.

  12. [On the Way to Culture-Sensitive Patient Information Materials: Results of a Focus Group Study].

    PubMed

    Ries, Zivile; Frank, Fabian; Bermejo, Isaac; Kalaitsidou, Chariklia; Zill, Jördis; Dirmaier, Jörg; Härter, Martin; Bengel, Jürgen; Hölzel, Lars

    2017-09-28

    Aim This study was part of a double-blind randomised controlled trial aimed to evaluate the effects of culture-sensitive patient information materials (PIM) compared with standard translated material. The study aimed to obtain the data for the development of culture sensitive PIM about unipolar depression for the 4 largest migrant groups in Germany (Turkish, Polish, Russian and Italian migration background). Method A qualitative study using 4 manual-based focus groups (FG), one for each migrant group, with 29 participants (9 with a Turkish (TüG), 8 with a Polish (PoG), 5 with a Russian (RuG) and 7 with an Italian (ItG) migration background) was conducted. The discussions were recorded, transcribed and analyzed using qualitative content analysis. Results 7 categories were identified. For the (1.) development of a good culture-sensitive PIM an easy language, a clear structure, an assessable extent of information and the avoidance of stereotypes were highlighted cross-culturally in all four FG. RuG and PoG had the largest (2.) lack of information about the German health care system. Concerning the (3.) illness perception RuG named problems with recognizing and understanding depression. PoG, RuG and TüG thematized (4.) feared consequences of the illness and of professional helpseeking. ItG, PoG, RuG had fears concerning (5.) psychotropic drugs as a result from insufficient knowledge about medication. For (6.) doctor-patient relationship cultural specifics were identified in RuG and TüG and for (7.) migration or culture specific reasons for depression in RuG, ItG and TüG. Conclusion Although the identified categories were relevant for all or for the majority of migrant groups, for most categories specific cultural aspects were discovered. These findings show the importance of a culture sensitive adaptation of PIM. © Georg Thieme Verlag KG Stuttgart · New York.

  13. Sensitivity of transillumination for detecting microcracks in feldspathic and zirconia ceramic materials.

    PubMed

    Beck, Nina; Graef, Friedrich; Gerstbrein, Oliver; Karl, Matthias

    2010-11-01

    Despite good clinical success rates of ceramic restorations, fractures of substructures made from high-strength dental ceramics remain an issue. Transillumination of ceramic restorations has been proposed as a means of quality assurance. The purpose of this study was to compare the sensitivity of transillumination and the fluorescent penetrant method (FPM) in detecting microcracks in zirconia and feldspathic ceramic materials. Two groups (n=20) of standardized plates were fabricated from zirconia ceramic (Cercon) and feldspathic ceramic (VITABLOCS Mark II for CEREC) materials, and central holes were created to induce microcracks. The plates were microscopically analyzed at ×20 magnification by means of transillumination and FPM. Based on whether the criterion crack was recognized or not recognized, contingency tables were developed. Fisher's exact test for count data was used to compare frequency distributions (α=.05). Minimum crack length as detected by FPM was 18 μm in zirconia ceramic and 17 μm in feldspathic ceramic. For transillumination, minimum detectable crack length was 54 μm in zirconia ceramic and 33 μm in feldspathic ceramic. Thirty-seven percent of cracks in feldspathic ceramic plates and 64% of cracks in zirconia ceramic plates could not be detected by means of transillumination. The conditional probabilities for a crack being detected by transillumination, although it was detected by FPM, were significantly lower than 1 for both materials (P<.001). Although transillumination was less sensitive than FPM on a relative scale, it was not possible to demonstrate a general difference between the 2 analyzing techniques by using statistical methods. Using FPM as a relative reference system, transillumination appears to be less sensitive in detecting microcracks in ceramic components. Copyright © 2010 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

  14. Selective Fragmentation of Radiation-Sensitive Novel Polymeric Resist Materials by Inner-Shell Irradiation.

    PubMed

    Chagas, Gabriela Ramos; Satyanarayana, Vardhineedi Sri Venkata; Kessler, Felipe; Belmonte, Guilherme Kretzmann; Gonsalves, Kenneth E; Weibel, Daniel Eduardo

    2015-08-05

    Two key concepts in extreme ultraviolet lithography (EUVL) are important for it to be a candidate for the mass production of future integrated circuits: the polymer formulation and the photofragmentation process. In this work, both concepts were carefully studied. The design and synthesis of radiation-sensitive organic polymeric materials based on the inclusion of a radiation-sensitive tetrahydrothiophenium functional group are outlined. A 1-(4-methacryloyoxy)naphthalene-1-yl)tetrahydro-1H-thiophenium trifluoromethanesulfonate (MANTMS) monomer containing the tetrahydrothiophenium group undergoes homo- and copolymerizations using free-radical polymerization with a 2,2'-azobis(isobutyronitrile) initiator. The surface photodegradation and oxidation of these novel polymeric materials were investigated using highly monochromatized soft X-rays from synchrotron radiation at the carbon K-edge excitation region. An efficient functionalization was observed when the excitation energy was tuned to C 1s → π*C═C. A high rate of defluorination and a loss of sulfonated groups as a result of an increase in the irradiation time for the MANTMS homopolymer thin films were mainly observed under the π*C═C excitation of the naphthyl functional groups. On the contrary, excitation similar to C 1s → π*C═O or C 1s → σ*C-F did not produce important degradation, showing a highly selective process of bond breaking. Additionally, the presence of methyl methacrylate copolymer in the original MANTMS yielded a much higher degree of stability against inner-shell radiation damage. Our results highlight the importance of choosing the right polymer formulation and excitation energy to produce a sensitive material for EUVL without using the concept of chemical amplification.

  15. Highly sensitive ethanol chemical sensor based on Ni-doped SnO₂ nanostructure materials.

    PubMed

    Rahman, Mohammed M; Jamal, Aslam; Khan, Sher Bahadar; Faisal, M

    2011-10-15

    Due to potential applications of semiconductor transition doped nanostructure materials and the important advantages of synthesis in cost-effective and environmental concerns, a significant effort has been consummated for improvement of Ni-doped SnO(2) nanomaterials using hydrothermal technique at room conditions. The structural and optical properties of the low-dimensional (average diameter, 52.4 nm) Ni-doped SnO(2) nanostructures were demonstrated using various conventional techniques such as UV/visible spectroscopy, FT-IR spectroscopy, X-ray powder diffraction (XRD), and Field-emission scanning electron microscopy (FE-SEM). The calcined doped material is an attractive semiconductor nanoparticle for accomplishment in chemical sensing by simple I-V technique, where toxic chemical (ethanol) is used as a target chemical. Thin-film of Ni-doped SnO(2) nanostructure materials with conducting coating agents on silver electrodes (AgE, surface area, 0.0216 cm(2)) revealed higher sensitivity and repeatability. The calibration plot is linear (R, 0.8440) over the large dynamic range (1.0 nM-1.0 mM), where the sensitivity is approximately 2.3148 μA cm(-2) mM(-1) with a detection limit of 0.6 nM, based on signal/noise ratio in short response time. Consequently on the basis of the sensitive communication among structures, morphologies, and properties, it is exemplified that the morphologies and the optical characteristics can be extended to a large scale in doping nanomaterials and proficient chemical sensors applications. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Development of high Sensitivity Materials for Applications in Magneto-Mechanical Torque Sensor

    SciTech Connect

    Shen, Yuping

    2003-01-01

    The Matteucci effect, which mainly manifests itself as the change of magnetization of a material with torsional stress, is currently of great technological interest because of the search for magnetic torque sensors. Magnetic torque sensors are important to future improvements of automobiles and industrial robots. It is well known that the magnetic state of a material depends on both the external magnetic field and external stress which causes strain and change in magnetization of the material. The former phenomenon has been well understood in both theory and application. However, the magnetic state dependence of stress is not adequately understood and the experimental data is of limited extent. In this project, the Matteucci effect in iron, cobalt, nickel and permalloy rods has been documented when they were in magnetic remanence status along the axis and nickel ring when they were in remanence status along the circumference. The effect of annealing on the magnetomechanical effect in nickel and the temperature dependence of the magnetomechanical sensitivity has also been examined. Factors related to the sensitivity at equilibrium condition have been theoretically developed. it is found in the experiments that the mechanism of magnetic domain wall movement plays an important role rather than the domain rotation. A higher sensitivity was found by domain wall movement mechanism than that by domain rotation mechanism. However, the domain wall movement will result in more hysteresis than domain wall rotation. The dynamic process of Matteucci effect of iron, cobalt, permally, especially as-fabricated and annealed nickel rods have been examined. A tentative explanation for the difference of these in terms of magnetic domain configuration and domain wall movement was given. As a result, another method of configuring and processing magnetic domains to get a linear magnetomechanical response other than that suggested by Garshelis, which was the basic method before the

  17. Understanding Organized Crime Groups in Russia and Their Illicit Sale of Weapons and Sensitive Materials

    DTIC Science & Technology

    1994-06-01

    community. In 1992, over 2,000 crimes were blamed on policemen.ln Most reports indicate however, that statistics like these merely represent the "tip... Crime Groups in Russia and Their Illicit Sale of Weapons and Sensitive Materials By David M. Lowy Thesis Advisor: Dana P. Eyre Approved for public release...CTZATI CUD55 IL. ZiUBJEC IbERMS cu. uere yu#Fcesnvy.o aiuofrby bdpcxwv) FIL OM S-atu Rusia Organized Crime , MaM6a Weapons Prolieraton Nuclea

  18. Terrestrial bitumen analogue of orgueil organic material demonstrates high sensitivity to usual HF-HCl treatment

    NASA Technical Reports Server (NTRS)

    Korochantsev, A. V.; Nikolaeva, O. V.

    1993-01-01

    The relationship between the chemical composition and the interlayer spacing (d002) of organic materials (OM's) is known for various terrestrial OM's. We improved this general trend by correlation with corresponding trend of natural solid bitumens (asphaltite-kerite-anthraxolite) up to graphite. Using the improved trend we identified bitumen analogs of carbonaceous chondrite OM's residued after HF-HCl treatment. Our laboratory experiment revealed that these analogs and, hence, structure and chemical composition of carbonaceous chondrite OM's are very sensitive to the HF-HCl treatment. So, usual extraction of OM from carbonaceous chondrites may change significantly structural and chemical composition of extracted OM.

  19. Sensitivity Analysis of Material Microstructure Effects on Predicted Crack Paths Using Finite Element Simulations

    NASA Astrophysics Data System (ADS)

    Jacob, Anaïs; Mehmanparast, Ali

    2016-07-01

    The effects of microstructure, grain and grain boundary (GB) properties on predicted damage paths and indicative crack propagation direction have been examined for a polycrystalline material using mesoscale finite element simulations. Numerical analyses were carried out on a compact tension specimen geometry containing granular mesh structures with random grain shapes and sizes of average diameter 100μm. Nanoindentation tests were performed to investigate the dependency of mesoscale hardness measurements on the indentation location with respect to grain and GB regions. Finite element results have shown that under tensile loading conditions, the predicted damage paths are very sensitive to the granular mesh structure, GB properties and individual grain properties. Furthermore, finite element results have revealed that the cracking mode (i.e., transgranular/intergranular) and maximum crack deviation angle are strongly dependent on the material microstructures employed in simulations.

  20. The Sensitivity of Residual Stresses of Cross-Ply Laminates to Manufacturing and Material Parameters

    NASA Astrophysics Data System (ADS)

    Lahtinen, H.

    2003-01-01

    By using a finite-element model elaborated, the sensitivity of residual stresses of polyester/glass cross-ply laminates to manufacturing and material parameters is investigated. The development of residual stresses in the laminates and the significance of the parameters for the problem are discussed. It is found that the main attention in calculating residual stresses should be focused on the properties of resin, which must be measured with care. The most important parameters related to the resin are, of course, its stiffness, thermal expansion, and chemical shrinkage, while the properties of fibers can be obtained from material handbooks with a sufficient accuracy. In curing a thin laminate in an autoclave, the simulation of chemical reactions and the parameters needed in thermal analysis are quite insignificant, because, in practice, the autoclave temperature and the properties of the mold determine the laminate temperature history.

  1. Materials, interfaces, and photon confinement in dye-sensitized solar cells.

    PubMed

    Lee, Byunghong; Hwang, Dae-Kue; Guo, Peijun; Ho, Shu-Te; Buchholtz, D B; Wang, Chiu-Yen; Chang, R P H

    2010-11-18

    A series of experiments have been carried out to study the effects of materials quality, surface and interfacial modification, and photon confinement on standard dye-sensitized solar cells. For these studies, both physical and optical characterization of the materials has been performed in detail. In addition, DC and AC impedance measurements along with kinetic charge-transport modeling of experimental results have yielded information on how to systematically optimize the cell efficiency. The same kinetic model has been used to interpret the results of a series of experiments on interfacial modification studies using fluorine etching in combination with TiCl(4) surface treatment. By using specially designed photonic crystals to confine the photons in the cells, it is shown that the best cell efficiency can be further increased by about 13%.

  2. Materials, Interfaces, and Photon Confiement in Dye-Sensitized Solar Cells

    SciTech Connect

    Lee, B.; Hwang, D.; Guo, P. J.; Ho, S. T.; Buchholtz, D. B.; Wang, C. Y.; Chang, R.P.H.

    2010-11-18

    A series of experiments have been carried out to study the effects of materials quality, surface and interfacial modification, and photon confinement on standard dye-sensitized solar cells. For these studies, both physical and optical characterization of the materials has been performed in detail. In addition, DC and AC impedance measurements along with kinetic charge-transport modeling of experimental results have yielded information on how to systematically optimize the cell efficiency. The same kinetic model has been used to interpret the results of a series of experiments on interfacial modification studies using fluorine etching in combination with TiCl{sub 4} surface treatment. By using specially designed photonic crystals to confine the photons in the cells, it is shown that the best cell efficiency can be further increased by about 13%.

  3. A material sensitivity study on the accuracy of deformable organ registration using linear biomechanical models.

    PubMed

    Chi, Y; Liang, J; Yan, D

    2006-02-01

    Model-based deformable organ registration techniques using the finite element method (FEM) have recently been investigated intensively and applied to image-guided adaptive radiotherapy (IGART). These techniques assume that human organs are linearly elastic material, and their mechanical properties are predetermined. Unfortunately, the accurate measurement of the tissue material properties is challenging and the properties usually vary between patients. A common issue is therefore the achievable accuracy of the calculation due to the limited access to tissue elastic material constants. In this study, we performed a systematic investigation on this subject based on tissue biomechanics and computer simulations to establish the relationships between achievable registration accuracy and tissue mechanical and organ geometrical properties. Primarily we focused on image registration for three organs: rectal wall, bladder wall, and prostate. The tissue anisotropy due to orientation preference in tissue fiber alignment is captured by using an orthotropic or a transversely isotropic elastic model. First we developed biomechanical models for the rectal wall, bladder wall, and prostate using simplified geometries and investigated the effect of varying material parameters on the resulting organ deformation. Then computer models based on patient image data were constructed, and image registrations were performed. The sensitivity of registration errors was studied by perturbating the tissue material properties from their mean values while fixing the boundary conditions. The simulation results demonstrated that registration error for a subvolume increases as its distance from the boundary increases. Also, a variable associated with material stability was found to be a dominant factor in registration accuracy in the context of material uncertainty. For hollow thin organs such as rectal walls and bladder walls, the registration errors are limited. Given 30% in material uncertainty

  4. A material sensitivity study on the accuracy of deformable organ registration using linear biomechanical models

    SciTech Connect

    Chi, Y.; Liang, J.; Yan, D.

    2006-02-15

    Model-based deformable organ registration techniques using the finite element method (FEM) have recently been investigated intensively and applied to image-guided adaptive radiotherapy (IGART). These techniques assume that human organs are linearly elastic material, and their mechanical properties are predetermined. Unfortunately, the accurate measurement of the tissue material properties is challenging and the properties usually vary between patients. A common issue is therefore the achievable accuracy of the calculation due to the limited access to tissue elastic material constants. In this study, we performed a systematic investigation on this subject based on tissue biomechanics and computer simulations to establish the relationships between achievable registration accuracy and tissue mechanical and organ geometrical properties. Primarily we focused on image registration for three organs: rectal wall, bladder wall, and prostate. The tissue anisotropy due to orientation preference in tissue fiber alignment is captured by using an orthotropic or a transversely isotropic elastic model. First we developed biomechanical models for the rectal wall, bladder wall, and prostate using simplified geometries and investigated the effect of varying material parameters on the resulting organ deformation. Then computer models based on patient image data were constructed, and image registrations were performed. The sensitivity of registration errors was studied by perturbating the tissue material properties from their mean values while fixing the boundary conditions. The simulation results demonstrated that registration error for a subvolume increases as its distance from the boundary increases. Also, a variable associated with material stability was found to be a dominant factor in registration accuracy in the context of material uncertainty. For hollow thin organs such as rectal walls and bladder walls, the registration errors are limited. Given 30% in material uncertainty

  5. Contaminant tailing in highly heterogeneous porous formations: Sensitivity on model selection and material properties

    NASA Astrophysics Data System (ADS)

    Maghrebi, Mahdi; Jankovic, Igor; Weissmann, Gary S.; Matott, L. Shawn; Allen-King, Richelle M.; Rabideau, Alan J.

    2015-12-01

    Coupled impacts of slow advection, diffusion and sorption were investigated using two heterogeneity models that differ in structure and in the mathematical framework that was used to simulate flow and transport and to quantify contaminant tailing. Both models were built using data from a highly heterogeneous exposure of the Borden Aquifer at a site located 2 km north-west of the Stanford-Waterloo experimental site at Canadian Forces Base Borden, Ontario, Canada. The inclusions-based model used a simplified representation of the different materials found at the site, while the second model was based on transitional probability geostatistics of the formation. These two models were used to investigate sensitivity of contaminant tailing on model selection and on geometric and material properties. While simulations were based on data collected at Borden, models were exercised beyond the geometric and material properties that characterize the site. Various realizations have identified very low conductive silty clay, found at volume fraction of 23.4%, as the material with dominant influence on tailing, and vertical diffusion in and out of low conductive units, affected by sorption, as the dominant transport mechanism causing tailing. The two models yielded almost identical transport results when vertical correlation lengths of silty clay were matched. Several practical implications relevant for characterization of low conductive units were identified and briefly discussed.

  6. Phase sensitive thermography for quality assessment of giant magnetostrictive composite materials

    NASA Astrophysics Data System (ADS)

    Yang, Peng; Law, Chiu T.; Elhajjar, Rani

    2017-04-01

    Giant magnetostrictive materials are increasingly proposed for smart material applications such as in sensors, actuators, and energy harvesting applications. In a composites form, the materials are combined in particle form with polymer matrix composites. Reviewing the literature on this topic, the reader observes a large amount of variability in the reported properties that are typically based on recording (overall or localized) strain and magnetic field with non-collocating strain gages and a gauss meter, i.e. far field measurements. Previously the linking of the microstructure in magnetostrictive composite to the spatial variability of the localized magnetostrictive response, a significant factor for the composite performance in sensing and acutuation, has not been received adequate attention. In this paper, a full-field phase-sensitive thermography method is proposed to use full-field infrared measurements to infer changes in the microstructure in magnetostrictive polymer composites under a cyclic magnetic field. The results show how defects in the material can be rapidly identified from the proposed approach in inspecting the manufactured smart composites.

  7. Equivalence principles and electromagnetism

    NASA Technical Reports Server (NTRS)

    Ni, W.-T.

    1977-01-01

    The implications of the weak equivalence principles are investigated in detail for electromagnetic systems in a general framework. In particular, it is shown that the universality of free-fall trajectories (Galileo weak equivalence principle) does not imply the validity of the Einstein equivalence principle. However, the Galileo principle plus the universality of free-fall rotation states does imply the Einstein principle.

  8. Alternative materials and processing techniques for optimized nanostructures in dye-sensitized solar cells.

    PubMed

    Hart, Judy N; Cheng, Yi-Bing; Simon, George P; Spiccia, Leone

    2008-05-01

    Dye-sensitized solar cells (DSSCs) represent an exciting application of nanotechnology and offer an appealing alternative to conventional solar cells based on photovoltaic devices, with significantly reduced production and material costs. However, further improvements are required to enhance the commercial viability of these solar cells. These improvements may be achieved through the careful manipulation of the structure at the nanoscale and the application of novel processing techniques, which may help to increase the efficiency of these solar cells, improve the ease of manufacture and allow the production of flexible, solid-state solar cells. For example, the use of a nanometre-thick coating of an insulating oxide over the semiconducting film in these solar cells may reduce recombination losses. Also, selective heating techniques such as microwave heating may assist in the production of efficient solar cells on polymer, rather than glass, substrates, by allowing a rapid heat treatment to be applied to the titanium dioxide film at a higher temperature than would be possible with conventional heating. Some novel approaches to the production of semiconducting thin films for dye-sensitized solar cells, as well as the use of alternative materials and nanostructures, are reviewed.

  9. The Stanford equivalence principle program

    NASA Technical Reports Server (NTRS)

    Worden, Paul W., Jr.; Everitt, C. W. Francis; Bye, M.

    1989-01-01

    The Stanford Equivalence Principle Program (Worden, Jr. 1983) is intended to test the uniqueness of free fall to the ultimate possible accuracy. The program is being conducted in two phases: first, a ground-based version of the experiment, which should have a sensitivity to differences in rate of fall of one part in 10(exp 12); followed by an orbital experiment with a sensitivity of one part in 10(exp 17) or better. The ground-based experiment, although a sensitive equivalence principle test in its own right, is being used for technology development for the orbital experiment. A secondary goal of the experiment is a search for exotic forces. The instrument is very well suited for this search, which would be conducted mostly with the ground-based apparatus. The short range predicted for these forces means that forces originating in the Earth would not be detectable in orbit. But detection of Yukawa-type exotic forces from a nearby large satellite (such as Space Station) is feasible, and gives a very sensitive and controllable test for little more effort than the orbiting equivalence principle test itself.

  10. Nanoporous framework materials interfaced with mechanical sensors for highly-sensitive chemical sensing.

    SciTech Connect

    Lee, Jin-Hwan; Skinner, Jack L.; Houk, Ronald J. T.; Fischer, Roland A.; Robinson, Alex Lockwood; Allendorf, Mark D.; Yusenko, Kirill; Meilikhov, Mikhail; Hesketh, Peter J.; Venkatasubramanian, Anandram; Thornberg, Steven Michael

    2010-04-01

    We will describe how novel nanoporous framework materials (NFM) such as metal-organic frameworks (MOFs) can be interfaced with common mechanical sensors, such as surface acoustic wave (SAW), microcantilever array, and quartz crystal microbalance (QCM) devices, and subsequently be used to provide selectivity and sensitivity to a broad range of analytes including explosives, nerve agents, and volatile organic compounds (VOCs). NFM are highly ordered, crystalline materials with considerable synthetic flexibility resulting from the presence of both organic and inorganic components within their structure. Chemical detection using micro-electro-mechanical-systems (MEMS) devices (i.e. SAWs, microcantilevers) requires the use of recognition layers to impart selectivity. Unlike traditional organic polymers, which are dense, the nanoporosity and ultrahigh surface areas of NFM allow for greater analyte uptake and enhance transport into and out of the sensing layer. This enhancement over traditional coatings leads to improved response times and greater sensitivity, while their ordered structure allows chemical tuning to impart selectivity. We describe here experiments and modeling aimed at creating NFM layers tailored to the detection of water vapor, explosives, CWMD, and volatile organic compound (VOCs), and their integration with the surfaces of MEMS devices. Molecular simulation shows that a high degree of chemical selectivity is feasible. For example, a suite of MOFs can select for strongly interacting organics (explosives, CWMD) vs. lighter volatile organics at trace concentrations. At higher gas pressures, the CWMD are deselected in favor of the volatile organics. We will also demonstrate the integration of various NFM on the surface of microcantiliver arrays, QCM crystals, and SAW devices, and describe new synthetic methods developed to improve the quality of NFM coatings. Finally, MOF-coated MEMS devices show how temperature changes can be tuned to improve response

  11. A History of the Chemical Innovations in Silver-Halide Materials for Color PhotographyII. Color-Forming Development, Part 5. Coupler Innovations after the 1970's—Two-Equivalent Coupler and DIR Coupler

    NASA Astrophysics Data System (ADS)

    Oishi, Yasushi

    After the 1970's on, several manufacturers including Fuji Film, Konica and Agfa-Gevaert participated in innovating color photographic materials by adding their own coupler chemistry to the technological architecture built by Kodak before then. One area of their major advances was development of the couplers having a coupling-off organic group. One of their functional forms was two-equivalent coupler which made the dye-forming process efficient and made the photosensitive layers slim. And another was DIR coupler which improved dramatically the image quality of color negative materials. In this paper a historical overview of these innovations is constructed from the technical documents, mainly patents.

  12. Superconducting Gamma/Neutron Spectrometer Task 1 Completion Report Evaluation of Candidate Neutron-Sensitive Materials

    SciTech Connect

    Bell, Z.W.; Lamberti, V.E.

    2002-06-20

    A review of the scientific literature regarding boron- and lithium-containing compounds was completed. Information such as Debye temperature, heat capacity, superconductivity properties, physical and chemical characteristics, commercial availability, and recipes for synthesis was accumulated and evaluated to develop a list of neutron-sensitive materials likely to perform properly in the spectrometer. The best candidate borides appear to be MgB{sub 2} (a superconductor with T{sub c} = 39 K), B{sub 6}Si, B{sub 4}C, and elemental boron; all are commercially available. Among the lithium compounds are LiH, LiAl, Li{sub 12}Si{sub 7}, and Li{sub 7}Sn{sub 2}. These materials have or are expected to have high Debye temperatures and sufficiently low heat capacities at 100 mK to produce a useful signal. The responses of {sup 10}B and {sup 6}Li to a fission neutron spectrum were also estimated. These demonstrated that the contribution of scattering events is no more than 3% in a boron-based system and 1.5% in a lithium-based system. This project is concerned with the development of materials for use in a cryogenic neutron spectrometer and is complementary to work in progress by Labov at LLNL to develop a cryogenic gamma ray spectrometer. Refrigeration to 100 mK lowers the heat capacity of these materials to the point that the energy of absorbed gamma and x rays, nuclei scattered by fast neutrons, and ions from (n, {alpha}) reactions produce a measurable heat pulse, from which the energy of the incident radiation may be deduced. The objective of this project is the discovery, fabrication, and testing of candidate materials with which a cryogenic neutron spectrometer may be realized.

  13. Mapping Proxy Sensitivity: A New Technique for Compositional Analysis of Cultured Biominerals and Inorganically Precipitated Materials

    NASA Astrophysics Data System (ADS)

    Gagnon, A. C.; DePaolo, D. J.; DeYoreo, J.; Spero, H. J.; Russell, A. D.

    2011-12-01

    Mineral composition is controlled by a host of environmental factors during precipitation. To build accurate paleo-reconstructions we need to separate the impact of each parameter on proxy behavior and use these data to build a chemical-scale understanding of mineral growth. Biomineral culture and inorganic precipitation experiments, where growth parameters can be manipulated independently, are uniquely suited to calibrate proxies and probe mechanism. Culture and precipitation experiments often involve overgrowth of an initial material. For example, seed crystals are used to control mineralogy and avoid nucleation during inorganic precipitation, while culture experiments in marine organisms typically start with wild specimens. New growth corresponding to the experimental conditions must be resolved from the initial material. Separation is typically achieved using microanalysis, skeletal dissection, or estimates of the initial mass and composition. Each approach imposes limits on the accuracy, precision or types of materials that can be analyzed. Slow growth rates and complicated geometries can make these techniques especially challenging when applied to biominerals. We present a method of compositional analysis for use in biological culture and inorganic growth experiments that overcomes many of these challenges. This method relies on growth in a mixed element stable isotope spike, requires neither the initial mass nor the initial composition to be known, harnesses the precision and sensitivity of bulk analysis, and applies even when it is impossible to physically identify newly grown material. Error analysis suggests this method can significantly improve the precision of metal/calcium measurements in experimentally grown material compared to current methods. Furthermore, the method can isolate different events through time, separating, for example, the impact of day and night cycles on biomineral composition. We will present metal/calcium ratios measured using the

  14. Use of maxillofacial laboratory materials to construct a tissue-equivalent head phantom with removable titanium implantable devices for use in verification of the dose of intensity-modulated radiotherapy.

    PubMed

    Morris, K

    2017-02-25

    The dose of radiotherapy is often verified by measuring the dose of radiation at specific points within a phantom. The presence of high-density implant materials such as titanium, however, may cause complications both during calculation and delivery of the dose. Numerous studies have reported photon/electron backscatter and alteration of the dose by high-density implants, but we know of no evidence of a dosimetry phantom that incorporates high density implants or fixtures. The aim of the study was to design and manufacture a tissue-equivalent head phantom for use in verification of the dose in radiotherapy using a combination of traditional laboratory materials and techniques and 3-dimensional technology that can incorporate titanium maxillofacial devices. Digital designs were used together with Mimics® 18.0 (Materialise NV) and FreeForm® software. DICOM data were downloaded and manipulated into the final pieces of the phantom mould. Three-dimensional digital objects were converted into STL files and exported for additional stereolithography. Phantoms were constructed in four stages: material testing and selection, design of a 3-dimensional mould, manufacture of implants, and final fabrication of the phantom using traditional laboratory techniques. Three tissue-equivalent materials were found and used to successfully manufacture a suitable phantom with interchangeable sections that contained three versions of titanium maxillofacial implants. Maxillofacial and other materials can be used to successfully construct a head phantom with interchangeable titanium implant sections for use in verification of doses of radiotherapy.

  15. Generic equivalence of dermatologic products. How equivalent is equivalent?

    PubMed

    Doering, P L; Araujo, O E; Flowers, F P

    1987-05-01

    More and more pharmaceutical products are becoming available under the generic designation as patents for their brand-name counterparts expire. Although some generic products are exact duplicates of the brand-name drug, others may vary with regard to their inactive ingredients or in other ways. Sometimes these allowable variations in product formulation are clinically significant for certain individuals. Therefore it is important for both the prescriber and the dispenser of medication to recognize potential differences in marketed products so that a truly equivalent preparation can be provided when a generic substitution is made. This article chronicles a case in which miscommunication and noncommunication led to the suboptimal treatment of a skin disease with a generic "equivalent." Suggestions are made for improving interprofessional communication so that the patient's needs are served to the maximum degree.

  16. Photoanisotropy in polarization-sensitive polymer materials based on the media with covalently-bonded components

    NASA Astrophysics Data System (ADS)

    Chaganava, Irakli; Kilosanidze, Barbara; Kakauridze, George; Oriol, Luis; Piñol, Milagros; Martinez-Felipe, Alfonso

    2017-02-01

    The well-known scalar photochromism phenomenon is a reversible phototransformation of chemical species between two forms having different absorption spectra. It is observed under the action of actinic light regardless of its polarization state. Unlike this in some high-efficient polarization-sensitive azopolymeric materials, we have observed a welldeveloped vector polyphotochromism which appears as a light-induced area with spectral selectivity for the linearly polarized probing beams. A sharp change in the transmission spectrum of the material have been observed when we placed an irradiated area of the sample between crossed polarizers, while the transmission spectrum of the sample remained practically unchanged in case of probing by unpolarized light. The effect has a purely vector nature, while the transmission spectrum of the exposed material essentially changes in case of observing between crossed polarizers and the change in the spectrum unambiguously depends on the energy exposure. A significant dependence of the kinetic of the vector polyphotochromism induction on the power density of linearly polarized actinic light (445 nm) is shown for probing beam of 635 nm. It is also shown that the kinetics of the effect depends on the photosensitive layer thickness and the concentration of the chromophore. The experiments were carried out for two synthesized side-chain azopolymers obtained as immobilized polar azo dyes on polymethylmethacrylate backbone. It is clearly shown a light-controlled spectral selectivity of the sample activated by the various doses of the stimulating radiation.

  17. Sensitive Detection of ssDNA Using an LRET-Based Upconverting Nanohybrid Material.

    PubMed

    Jesu Raj, Joe Gerald; Quintanilla, Marta; Mahmoud, Khaled A; Ng, Andy; Vetrone, Fiorenzo; Zourob, Mohammed

    2015-08-26

    Water-dispersible, optical hybrid nanoparticles are preferred materials for DNA biosensing due to their biocompatibility. Upconverting nanoparticles are highly desirable optical probes in sensors and bioimaging owing to their sharp emission intensity in the visible region. We herein report a highly sensitive ss-DNA detection based on an energy transfer system that uses a nanohybrid material synthesized by doping NaYF4:Tm(3+)/Yb(3+) upconverting nanoparticles (UCNPs) on silica coated polystyrene-co-acrylic acid (PSA) nanoparticles (PSA/SiO2) as the donor, and gold nanoparticles (AuNPs) decorated with Ir(III) complex as the acceptor. UCNPs tagged on PSA/SiO2 and the cyclometalated Ir(III)/AuNP conjugates were then linked through the ss-DNA sequence. Sequential addition of the target DNA to the probe molecular beacon complex resulted in the separation of the optical nanohybrid material and the quencher, leading to a measurable increase in the blue fluorescence emission intensity. Our results have shown a linear relationship between the fluorescence intensity and target DNA concentration down to the picomolar.

  18. Compact Detection System for High Sensitivity Hydrogen Profiling of Materials by Nuclear Reaction Analysis

    SciTech Connect

    Marble, Daniel Keith; Urban, Ben; Pacheco, Jose

    2009-03-10

    Hydrogen is a ubiquitous contaminant that is known to have dramatic effects on the electrical, chemical, and mechanical properties of many types of materials in even minute quantities. Thus, the detection of hydrogen in materials is of major importance. Nuclear Reaction Analysis (NRA) is a powerful technique for nondestructive profiling hydrogen in materials. However, NRA has found only limited use in many applications because of poor sensitivity due to cosmic ray background (CSRB). Most attempts to eliminate CSRB to achieve ppm detection levels using higher energy nuclear reactions or tons of passive shielding are not compatible with commercial ion beam analysis space and equipment requirements Zimmerman, et al. have previously reported upon a coincidence detector that meets IBA space requirements and reduces the cosmic ray background, but the detector suffers from lower detection efficiency and small sample size. We have replaced the BGO well detector in the Zimmerman coincidence detection scheme with a larger Nal well detector and used faster timing electronics to produce a detector that can handle larger samples with higher detection efficiency, and still eliminate cosmic ray background.

  19. TiO2-nanotube-based dye-sensitized solar cells containing fluorescent material.

    PubMed

    Kim, Woong-Rae; Lee, Young-Joon; Park, Hun; Lee, Jae-Joon; Choi, Won-Youl

    2013-05-01

    We fabricated a dye-sensitized solar cells (DSCs) with TiO2 nanotube arrays obtained by anodization of Ti foil. Vertical structure of TiO2 nanotube arrays is very attractive due to a high electron transfer from dye to electrode. To improve the power conversion efficiency, fluorescent material, F-6377, was applied in TiO2-nanotube-based DSCs to use a light spectrum efficiently. Fluorescent material was absorbed the different wavelength of 460 nm from the light absorbed by N719 dye. Fluorescent material to emit the absorbed light energy provided an additional light for dye in DSCs and additional electrons was generated. Thickness of TiO2 nanotube arrays grown by anodic oxidation was 15 microm. N719 dye and 13(-)/l(-) electrolyte were used to fabricate the DSCs. The short circuit current densities (J(sc)) and the power conversion efficiency in DSCs with fluorescent were 10.8 mA/cm2 and 2.48%, respectively. Electrochemical impedance spectroscopy (EIS) was observed to understand an electron transfer and life time.

  20. 14 CFR 1213.107 - Preventing unauthorized release of sensitive but unclassified (SBU) information/material to the...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 5 2012-01-01 2012-01-01 false Preventing unauthorized release of sensitive but unclassified (SBU) information/material to the news media. 1213.107 Section 1213.107... INFORMATION MEDIA § 1213.107 Preventing unauthorized release of sensitive but unclassified (SBU) information...

  1. [Antibiotic sensitivity of beta-hemolytic streptococci isolated from throat swabs and purulent material].

    PubMed

    Jachna-Sawicka, Katarzyna; Pietrzak, Anna; Bogiel, Tomasz; Gospodarek, Eugenia

    2010-01-01

    The aim of this study was to evaluate the prevalence and susceptibility of beta-hemolytic streptococci isolated from throat swabs (142--29.9%) and purulent material (333--70.1%) taken from patients treated at University Hospital dr. A. Jurasz in Bydgoszcz Collegium Medicum. L. Rydygier in Bydgoszcz, Nicolaus Copernicus University in Torun in 2005-2009. Of the 475 tested strains, 156 (32.8%) were identified as S. pyogenes. This species accounted for 38.8% of strains isolated from purulent material and 19.0% of swabs from the throat. Among the strains isolated from throat swabs of 62 (43.7%) were identified as Streptococcus group C. Only 5.1% strains were identified as Streptococcus group F. All strains of beta-hemolytic streptococci were susceptible to ampicillin or penicillin, fluoroquinolones, vancomycin and linezolid. Erythromycin-susceptible strains was 83.8%, and 89.1% for clindamycin. A total of 51.3% of erythromycin resistance strains had the cMLS(B) phenotype (63.3% for strains from throat swabs and 46.3% of the purulent materials). Sensitivity to tetracycline was characterized by 51.2% of strains of beta-hemolytic streptococci. The percentage of strains susceptible to this antibiotic among isolates from throat swabs was 63.1%, and purulent material--48.0%. The lowest percentage of strains susceptible to tetracycline (14.1%) were found among S. agalactiae and Streptococcus group G (33.6%) strains. During the study time, saw an increase in the percentage of strains susceptible to tetracycline and erythromycin.

  2. PATHOGEN EQUIVALENCY COMMITTEE UPDATE: PFRP EQUIVALENCY DETERMINATIONS

    EPA Science Inventory

    This presentation will:

    Review the mandate of the Pathogen Equivalency Committee
    Review the PEC's current membership of 10
    Discuss how a typical application is evaluated
    Note where information can be found
    List present deliberations/applications and describe t...

  3. PATHOGEN EQUIVALENCY COMMITTEE UPDATE: PFRP EQUIVALENCY DETERMINATIONS

    EPA Science Inventory

    This presentation will:

    Review the mandate of the Pathogen Equivalency Committee
    Review the PEC's current membership of 10
    Discuss how a typical application is evaluated
    Note where information can be found
    List present deliberations/applications and describe t...

  4. Structural and multi-scale rheophysical investigation of diphasic magneto-sensitive materials based on biopolymers.

    PubMed

    Roger, Stéphane; Sang, Yan Yip Cheung; Bee, Agnès; Perzynski, Régine; Di Meglio, Jean Marc; Ponton, Alain

    2015-08-01

    We present a structural and a multi-scale rheophysical investigation of magneto-sensitive materials based on biopolymers, namely aqueous solutions of sodium alginate incorporating magnetic maghemite nanoparticles, functionalized with adsorbed negative citrate ions. The large alginate ionic strength impacts the structure and the rheology of these nanocomposites in zero magnetic field. In given physico-chemical conditions, the system is fluid and homogeneous on macroscopic scales while it is diphasic on microscopic ones, containing micro-droplets coming from the demixion of the system. These micro-droplets are liquid and deformable under magnetic field. Their under-field elongation and their zero-field relaxation are directly observed by optical microscopy to determine their interfacial tension, their magnetic susceptibility and their internal viscosity. A structural analysis of the solutions of alginate chains and of the phase-separated mixtures of alginate and nanoparticles by Small Angle Scattering completes the local description of the system.

  5. Performance Maintenance of Dye-Sensitized Solar Cells Using a Latent Heat Storage Material

    NASA Astrophysics Data System (ADS)

    Haruki, Naoto; Horibe, Akihiko

    2017-07-01

    Recently, there has been considerable interest in various renewable energies. Among them, solar cell production has increased markedly because the photovoltaic is a clean and safe power generation method. The dye-sensitized solar cell (DSSC) has attracted much attention as an alternative to silicon solar cells due to lower manufacturing costs and plentiful resources for DSSC production. However, the performance of DSSCs has been limited by their durability and low photoelectric conversion efficiency. Temperature control of DSSCs via phase-change materials (PCMs) is expected to improve performance. In this study, DSSCs were heated or cooled with a heat exchanger copper block that was in contact with a PCM (heptadecane), while being irradiated by a solar simulator light source. The durability and photoelectric conversion efficiency of the DSSC improved under PCM temperature control.

  6. Versatile, high sensitivity, and automatized angular dependent vectorial Kerr magnetometer for the analysis of nanostructured materials.

    PubMed

    Teixeira, J M; Lusche, R; Ventura, J; Fermento, R; Carpinteiro, F; Araujo, J P; Sousa, J B; Cardoso, S; Freitas, P P

    2011-04-01

    Magneto-optical Kerr effect (MOKE) magnetometry is an indispensable, reliable, and one of the most widely used techniques for the characterization of nanostructured magnetic materials. Information, such as the magnitude of coercive fields or anisotropy strengths, can be readily obtained from MOKE measurements. We present a description of our state-of-the-art vectorial MOKE magnetometer, being an extremely versatile, accurate, and sensitivity unit with a low cost and comparatively simple setup. The unit includes focusing lenses and an automatized stepper motor stage for angular dependent measurements. The performance of the magnetometer is demonstrated by hysteresis loops of Co thin films displaying uniaxial anisotropy induced on growth, MnIr/CoFe structures exhibiting the so called exchange bias effect, spin valves, and microfabricated flux guides produced by optical lithography.

  7. Ignition Sensitivity and Electrical Conductivity of a Composite Energetic Material with Conductive Nanofillers

    SciTech Connect

    Eric S. Collins; Brandon R. Skelton; Michelle L. Pantoya; Fahmida Irin; Micah J. Green; Michael A. Daniels

    2014-12-01

    The safe handling of powdered composite energetic materials requires an understanding of their response to electrostatic ignition stimuli. A binary composite comprised of Al and polytetrafluoroethylene (PTFE) was tailored for ESD ignition sensitivity with varied concentrations of highly conductive nanofillers. The goal was to control the ESD ignition response of the Al+PTFE with small concentrations of nanofillers that may not significantly affect the overall combustion performance of the mixture. The nanofillers examined include carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs). Adding CNTs created percolation at a lower volumetric percentage than GNPs and were found to be the controlling nanofiller, creating percolation for the mixture containing both CNTs and GNPs. Various mixing methods were examined. Ignition was achieved only for adding nanofillers at a volumetric percentage and mixing method that led to a bulk conductivity of approximately 5x10-3 ?S/cm.

  8. Elastic airtight container for the compaction of air-sensitive materials

    NASA Astrophysics Data System (ADS)

    Shoulders, W. Taylor; Locke, Richard; Gaume, Romain M.

    2016-06-01

    We report on the design and fabrication of a simple and versatile elastic canister for the compaction and hot-pressing of air-sensitive materials. This device consists of a heated double-ended floating die assembly, enclosed in a compressible stainless steel bellows that allows the action of an external hydraulic press in a uniaxial motion. The enclosure is fitted with vacuum, gas, and electrical feedthroughs to allow for atmosphere control, heating, and in situ process monitoring. The overall chamber is compact enough to be portable and transferrable into and out of a standard laboratory glovebox, thus eliminating the problem of exposing samples to ambient atmosphere during loading and unloading. Our design has been tested up to 600 °C and 7500 kg-force applied load, conditions within which transparent ceramics of anhydrous halides can be produced.

  9. Finite-element modeling of bones from CT data: sensitivity to geometry and material uncertainties.

    PubMed

    Taddei, Fulvia; Martelli, Saulo; Reggiani, Barbara; Cristofolini, Luca; Viceconti, Marco

    2006-11-01

    The aim of this paper is to analyze how the uncertainties in modelling the geometry and the material properties of a human bone affect the predictions of a finite-element model derived from computed tomography (CT) data. A sensitivity analysis, based on a Monte Carlo method, was performed using three femur models generated from in vivo CT datasets, each subjected to two different loading conditions. The geometry, the density and the mechanical properties of the bone tissue were considered as random input variables. Finite-element results typically used in biomechanics research were considered as statistical output variables, and their sensitivity to the inputs variability assessed. The results showed that it is not possible to define a priori the influence of the errors related to the geometry definition process and to the material assignment process on the finite-element analysis results. The errors in the geometric representation of the bone are always the dominant variables for the stresses, as was expected. However, for all the variables, the results seemed to be dependent on the loading condition and to vary from subject to subject. The most interesting result is, however, that using the proposed method to build a finite-element model of a femur from a CT dataset of the quality typically achievable in the clinical practice, the coefficients of variation of the output variables never exceed the 9%. The presented method is hence robust enough to be used for investigating the mechanical behavior of bones with subject-specific finite-element models derived from CT data taken in vivo.

  10. Sensitive determination of carbendazim in orange juice by electrode modified with hybrid material.

    PubMed

    Razzino, Claudia A; Sgobbi, Lívia F; Canevari, Thiago C; Cancino, Juliana; Machado, Sergio A S

    2015-03-01

    This paper describes the application of a glassy carbon electrode modified with a thin film of mesoporous silica/multiwalled carbon nanotubes for voltammetric determination of the fungicide carbendazim (CBZ). The hybrid material, (SiO2/MWCNT), was obtained by a sol-gel process using HF as the catalyst. The amperometric response to CBZ was measured at +0.73 V vs. Ag/AgCl by square wave voltammetry at pH 8.0. SiO2/MWCNT/GCE responded to CBZ in the linear range from 0.2 to 4.0 μmol L(-1). The calculated detection limit was 0.056 μmol L(-1), obtained using statistical methods. The SiO2/MWCNT/GCE sensor presented as the main characteristics high sensitivity, low detection limit and robustness, allowing CBZ determination in untreated real samples. In addition, this strategy afforded remarkable selectivity for CBZ against ascorbic and citric acid which are the main compounds of the orange juice. The excellent sensitivity and selectivity yielded feasible application for CBZ detection in orange juice sample.

  11. Single-material solvent-sensitive actuator from poly(ionic liquid) inverse opals based on gradient dewetting.

    PubMed

    Wu, Hua; Kuang, Minxuan; Cui, Liying; Tian, Di; Wang, Minghui; Luan, Guoyou; Wang, Jingxia; Jiang, Lei

    2016-05-01

    A novel and reversible single-material solvent-sensitive actuator was developed from poly(ionic liquid) inverse opals based on a gradient wetting/dewetting process combining the strong hydrogen bonding interaction between the solvent and polymer. This study will provide an important insight for the design and fabrication of novel-type solvent-actuator materials.

  12. 14 CFR 1213.107 - Preventing unauthorized release of sensitive but unclassified (SBU) information/material to the...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... sensitive but unclassified (SBU) information/material to the news media. 1213.107 Section 1213.107 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION RELEASE OF INFORMATION TO NEWS AND.../material to the news media. (a) All NASA SBU information requires accountability and approval for release...

  13. 14 CFR § 1213.107 - Preventing unauthorized release of sensitive but unclassified (SBU) information/material to the...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... sensitive but unclassified (SBU) information/material to the news media. § 1213.107 Section § 1213.107 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION RELEASE OF INFORMATION TO NEWS AND.../material to the news media. (a) All NASA SBU information requires accountability and approval for release...

  14. 14 CFR 1213.107 - Preventing unauthorized release of sensitive but unclassified (SBU) information/material to the...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... sensitive but unclassified (SBU) information/material to the news media. 1213.107 Section 1213.107 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION RELEASE OF INFORMATION TO NEWS AND.../material to the news media. (a) All NASA SBU information requires accountability and approval for release...

  15. Shock sensitivity of energetic material and nanometric damage mechanisms in silica glass

    NASA Astrophysics Data System (ADS)

    Nomura, Ken-Ichi

    This dissertation focuses on molecular dynamics (MD) simulations of shock sensitivity of energetic material (EM) and nanometric damage mechanisms in amorphous SiO2 (a-SiO2). A scalable parallel MD algorithm incorporating first principles-based reactive force fields (ReaxFF) has been implemented to perform multimillion-to-billion atom chemically reactive MD simulations. Mechanical stimuli in energetic materials initiate chemical reactions at shock fronts prior to detonation. Multimillion-atom ReaxFF-MD simulations are performed to investigate atomistic mechanisms of shock-induced reaction initiation in 1,3,5-trinitro-1,3,5-triazine (RDX) crystal. The simulation reveals a bi-modal molecular response against a planar shock loading, which creates a nanoscale layered-structure of molecular dipole behind a shock front. The sensitivity of energetic crystals changes with defects such as voids, grain boundaries and cracks. By performing million-atom ReaxFF-MD simulations, the effects of microstructures in crystal on shock sensitivity have been investigated. MD simulation reveals the formation of a nanojet which focuses into a narrow beam as the void collapses. By increasing particle velocity, a pinning-depinning transition of the shock wave front at the void occurs. Shock loading simulation in a nanophase RDX crystal reveals a deformation mechanism that is mediated by molecular reorientation and conformation changes. Molecular rotation and deformation significantly reduce the energy barrier for the onset of slip. In contrast to crystalline solids, damage, flow and fracture in glass are still controversial areas. We have performed multimillion-atom MD simulations to investigate initiation and growth of wing cracks in confined silica glass. Under dynamic compression, frictional sliding of precrack surfaces nucleates nanovoids which evolve into nanocrack columns at the precrack tip. Nanocrack columns merge to form a wing crack, which grows via coalescence with nanovoids in the

  16. Formation of sensitive/active phases in metal and polymer-based structural materials

    NASA Astrophysics Data System (ADS)

    Asanuma, Hiroshi

    2002-11-01

    This paper describes new concepts the author has proposed and demonstrated to realize metal and polymer based sensitive and/or active structural material systems suitable for smart structures. Most of the developments have been done by simple and innovative methods without using sophisticated and expensive sensors and actuators. The following topics are mainly examined: (1) embedding optical fiber in aluminum matrix to use as sensors; (2) forming optical interference and loss type strain sensors in epoxy matrix simply by embedding and breaking notched optical fiber in it; (3) forming a multifunctional sensor in aluminum matrix for temperature and strain monitoring by embedding an oxidized nickel fiber; (4) fabricating multifunctional composites by using conventional structural materials - i) an active laminate of CFRP/aluminum of which unidirectional actuation is realized by electrical resistance heating of carbon fiber in the CFRP layer and its curvature change can be monitored using optical fiber multiply fractured in the CFRP layer, and ii) a multifunctional aluminum-matrix composite where oxidized titanium fiber is embedded for sensing temperature and strain, generation of heat for actuation.

  17. Near infrared organic semiconducting materials for bulk heterojunction and dye-sensitized solar cells.

    PubMed

    Singh, Surya Prakash; Sharma, G D

    2014-06-01

    Dye sensitized solar cells (DSSCs) and bulk heterojunction (BHJ) solar cells have been the subject of intensive academic interest over the past two decades, and significant commercial effort has been directed towards this area with the vison of developing the next generation of low cost solar cells. Materials development has played a vital role in the dramatic improvement of both DSSC and BHJ solar cell performance in the recent years. Organic conjugated polymers and small molecules that absorb solar light in the visible and near infrared (NIR) regions represent a class of emering materials and show a great potential for the use of different optoelectronic devices such as DSSCs and BHJ solar cells. This account describes the emering class of near infrared (NIR) organic polymers and small molecules having donor and acceptors units, and explores their potential applications in the DSSCs and BHJ solar cells. Copyright © 2014 The Chemical Society of Japan and Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Amplitude-sensitive modulation thermography to measure moisture in building materials

    NASA Astrophysics Data System (ADS)

    Wild, Walter; Buescher, Konstantin A.; Wiggenhauser, Herbert

    1998-03-01

    There have been reports about moisture detection in building walls by reflective IR-thermography. Typically, only limited results could be obtained because of the emission coefficient variations, leaking radiation or inhomogeneous illumination of the object. In addition, the quantitative relation between remission spectra and the moisture has often been unclear. Reflectometry uses constant excitation illumination which is recorded by the IR camera. With the use of the 'lock-in-technology' a low frequency modulated signal of an IR radiation source is coupled with the thermo camera and a frequency and phase sensitive signal from the thermal images can be derived. The advantage is, that emission coefficient dependencies are eliminated and that leaking radiation does not have any influence on the measured signal. The selective water measurement is possible, because there is an interference filter mounted in front of the radiator which has its transmission maximum at the wavelength of an absorption band of water. The area investigated is therefore illuminated under well defined circumstances and quantitative moisture measurement on the surface of building materials becomes a possibility. The illumination modulation is done with a sine wave to facilitate the calculation of the temporal intensity behavior of the amplitude signal. Subsequently, the amplitude image is used to determine the distribution and the level of moisture quantitatively. Point measurements in the laboratory were carried out on several building materials with changing moisture levels. It could be shown that this method successfully eliminates disturbing contributions to the measured signal like surface effects or leaking radiation.

  19. Investigation of Thermal Interface Materials Using Phase-Sensitive Transient Thermoreflectance Technique: Preprint

    SciTech Connect

    Feng, X.; King, C.; DeVoto, D.; Mihalic, M.; Narumanchi, S.

    2014-08-01

    With increasing power density in electronics packages/modules, thermal resistances at multiple interfaces are a bottleneck to efficient heat removal from the package. In this work, the performance of thermal interface materials such as grease, thermoplastic adhesives and diffusion-bonded interfaces are characterized using the phase-sensitive transient thermoreflectance technique. A multi-layer heat conduction model was constructed and theoretical solutions were derived to obtain the relation between phase lag and the thermal/physical properties. This technique enables simultaneous extraction of the contact resistance and bulk thermal conductivity of the TIMs. With the measurements, the bulk thermal conductivity of Dow TC-5022 thermal grease (70 to 75 um bondline thickness) was 3 to 5 W/(m-K) and the contact resistance was 5 to 10 mm2-K/W. For the Btech thermoplastic material (45 to 80 μm bondline thickness), the bulk thermal conductivity was 20 to 50 W/(m-K) and the contact resistance was 2 to 5 mm2-K/W. Measurements were also conducted to quantify the thermal performance of diffusion-bonded interface for power electronics applications. Results with the diffusion-bonded sample showed that the interfacial thermal resistance is more than one order of magnitude lower than those of traditional TIMs, suggesting potential pathways to efficient thermal management.

  20. Undoped and doped poly(tetraphenylbenzidine) as sensitive material for an impedimetric nitrogen dioxide gas dosimeter

    SciTech Connect

    Marr, I.; Moos, R.; Neumann, K.; Thelakkat, M.

    2014-09-29

    This article presents a nitrogen dioxide (NO{sub 2}) detecting gas dosimeter based on poly(tetraphenylbenzidine) poly(TPD) as nitrogen oxide (NO{sub x}) sensitive layer. Gas dosimeters are suitable devices to determine reliably low levels of analytes over a long period of time. During NO{sub x} exposure, the analyte molecules are accumulated irreversibly in the sensing layer of the dosimeter enhancing the conductivity of the hole conducting poly(TPD), which can be measured by impedance spectroscopy. Due to their possibility for low cost production by simple printing techniques and very good physical, photochemical, and electrochemical properties, poly(TPD)s are suitable for application in gas dosimeters operated at room temperature. We studied the effect of doping with a Co(III)-complex in combination with a conducting salt on the dosimeter behavior. Compared to the undoped material, a strong influence of the doping can be observed: the conductivity of the sensing material increases significantly, the noise of the signal decreases and an unwanted recovery of the sensor signal can be prevented, leading to a NO{sub x} detection limit <10 ppm.

  1. Enhanced power conversion efficiency of dye-sensitized solar cells assisted with phosphor materials

    NASA Astrophysics Data System (ADS)

    Lee, Yong-Min; Kim, Dong In; Hwang, Ki-Hwan; Nam, Sang Hun; Boo, Jin-Hyo

    2016-07-01

    Theoretically dye-sensitized solar cells (DSSCs) are high efficiency solar cells. However, DSSCs have lower power conversion efficiency (PCE) than silicon based solar cells. In this study, we use scattering layer and phosphor materials, such as ZrO2 and Zn2SiO4:Mn (Green), to enhance the PCE of DSSCs. The scattering layer and phosphor materials were prepared and used as an effective scattering layer on the transparent TiO2 photoelectrode through the doctor blade method. We confirmed that the scattering layer improves the PCE and J sc due to the enhancement of light harvesting by increasing the scattering and absorbance in the visible range. Under sun illumination AM 1.5 conditions, the PCE of the mesoporous TiO2 based DSSCs was 5.18%. The PCE of the DSSCs with ZrO2 scattering layer was 5.61% and Zn2SiO4:Mn as the scattering layer was enhanced to 5.72%. In order to compare the change in optical properties, DSSCs were measured by EQE, reflectance and PCE. At the same time, FE-SEM and XRD were used to confirm the structural changes in each layer. [Figure not available: see fulltext.

  2. 33 CFR 155.120 - Equivalents.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Equivalents. 155.120 Section 155.120 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION OIL OR HAZARDOUS MATERIAL POLLUTION PREVENTION REGULATIONS FOR VESSELS General § 155.120 Equivalents...

  3. 46 CFR 161.002-17 - Equivalents.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 6 2010-10-01 2010-10-01 false Equivalents. 161.002-17 Section 161.002-17 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS... require engineering evaluations and tests to demonstrate the equivalence of the substitute. ...

  4. Active microwave water equivalence

    NASA Technical Reports Server (NTRS)

    Boyne, H. S.; Ellerbruch, D. A.

    1980-01-01

    Measurements of water equivalence using an active FM-CW microwave system were conducted over the past three years at various sites in Colorado, Wyoming, and California. The measurement method is described. Measurements of water equivalence and stratigraphy are compared with ground truth. A comparison of microwave, federal sampler, and snow pillow measurements at three sites in Colorado is described.

  5. Photoelectrochemical characteristics of dye-sensitized solar cells incorporating innovative and inexpensive materials

    NASA Astrophysics Data System (ADS)

    Harlow, Lisa Jean

    The use of energy is going to continue to increase rapidly due to population and economic advances occurring throughout the world. The most widely used energies produce carbon dioxide during their combustion and have finite limits on how much of these resources are available. A strong push to utilizing renewable energy is necessary to keep up with the demand. The only renewable energy that has unlimited supply is solar. Our goal is to find cost-effective alternatives to historically the most extensively used materials in dye-sensitized solar cells. In order to rely on efficiency changes coinciding with the introduction of a new component, a standard baseline of performance is necessary to establish. A reproducible fabrication procedure composed of standard materials was instituted; the efficiency parameters exhibited a less than 10% standard deviation for any set of solar cells. Any modifications to the cell components would be apparent in the change in efficiency. Our cell modifications focused on economical alternatives to the electrolyte, the counter electrode and the chromophore. Solution-based electrolytes were replaced with a non-volatile ionic liquid, 1-methyl-3-propylimidazolium iodide, and then a poly(imidazole-functionalized) silica nanoparticle. Solid-state electrolytes reduce or prevent leakage and could ease manufacturing in large-scale devices. Platinum has been the counter electrode catalyst primarily used with the iodide/triiodide redox couple, but is a rare metal making it rather costly. We reduce platinum loading by introducing a novel counter electrode that employs platinum nanoparticles embedded on a graphene nanoplatelet paper. The highly conductive carbon base also negates the use of the expensive conductive substrate necessary for the platinum catalyst, further reducing cost. We also study the differences in transitioning from ruthenium polypyridyls to iron-based chromophores in dye-sensitized solar cells. Iron introduces low-lying ligand

  6. Technique sensitivity: biological factors contributing to clinical success with various restorative materials.

    PubMed

    Cox, C F; Tarim, B; Kopel, H; Gürel, G; Hafez, A

    2001-08-01

    Since the 1950s, clinicians have relied on various formulations of Ca(OH)2 to stimulate dentin bridge formation. Various studies (Kozlov and Massler, 1966; Massler, 1967; Brännström, 1978; Cox et al., 1987; Snuggs et al., 1993) have demonstrated that pulp healing and dentin bridging can occur against a pH spectrum of materials. Recent studies (Akimoto et al., 1998; Cox et al., 1998, 1999; Tarim et al., 1998; Kitasako et al., 1999; Hafez et al., 2000) have reported successful pulp healing and dentin bridging using adhesives for direct capping of exposed pulps. However, others (Costa et al., 1997; Stanley and Pameijer, 1997; Pameijer, 1998; Hebling et al., 1999; Carvalho et al., 2000) have reported unsatisfactory results when exposures were direct-capped with adhesives. Biological and technical factors, or a combination of both, might be postulated to explain these differences. Recent studies have demonstrated that biological success is dependent upon proper hemorrhage control at the exposure site. This review explores the differences and common factors influencing successful dentin bridging, focusing on data derived from animal studies conducted according to ISO usage guidelines for cavity preparation and material placement. In the past, there has been concern that etching of vital dentin leads to immediate pulp death due to low pH. Recent studies have reported that acidic cements cause breakdown of only the smear layer and fail to seal the restoration interface, leading to inflammation and necrosis. A properly hybridized dentinadhesive interface provides a "bacteriometic" seal to both dentin and pulp tissues. Recent ISO usage studies have shown a high incidence of dentin bridging with adhesives following proper hemorrhage control and removal of both operative debris and biofilm at the dentin-pulp interface by agents such as NaOCl. These are important technique-sensitivity factors to be considered for pulp healing and dentin bridge formation.

  7. Controlling Explosive Sensitivity of Energy-Related Materials by Means of Production and Processing in Electromagnetic Fields

    NASA Astrophysics Data System (ADS)

    Rodzevich, A. P.; Gazenaur, E. G.; Kuzmina, L. V.; Krasheninin, V. I.; Sokolov, P. N.

    2016-08-01

    The present work is one of the world first attempts to develop effective methods for controlling explosive sensitivity of energy-related materials with the help of weak electric (up to 1 mV/cm) and magnetic (0.001 T) fields. The resulting experimental data can be used for purposeful alternation of explosive materials reactivity, which is of great practical importance. The proposed technology of producing and processing materials in a weak electric field allows forecasting long-term stability of these materials under various energy impacts.

  8. Tuned sensitivity towards H{sub 2}S and NH{sub 3} with Cu doped barium strontium titanate materials

    SciTech Connect

    Simion, C. E. Teodorescu, V. S.; Stănoiu, A.; Sackmann, A.; Ruşti, C. F.; Piticescu, R. M.

    2014-11-05

    The different amount of Cu-doped Barium Strontium Titanate (BST) thick film materials have been tested for their gas-sensing performances towards NH{sub 3} and H{sub 2}S under dry and 50% relative humidity (RH) background conditions. The optimum NH{sub 3} sensitivity was attained with 0.1mol% Cu-doped BST whereas the selective detection of H{sub 2}S was highlighted using 5mol% Cu-doped BST material. No cross-sensitivity effects to CO, NO{sub 2}, CH{sub 4} and SO{sub 2} were observed for all tested materials operated at their optimum temperature (200°C) under humid conditions (50% RH). The presence of humidity clearly enhances the gas sensitivity to NH{sub 3} and H{sub 2}S detection.

  9. Equivalent Neutral Wind

    NASA Technical Reports Server (NTRS)

    Liu, W. Timothy; Tang, Wenqing

    1996-01-01

    The definition of equivalent neutral wind and the rationale for using it as the geophysical product of a spaceborne scatterometer are reviewed. The differences between equivalent neutral wind and actual wind, which are caused by atmospheric density stratification, are demonstrated with measurements at selected locations. A method of computing this parameter from ship and buoy measurements is described and some common fallacies in accounting for the effects of atmospheric stratification on wind shear are discussed. The computer code for the model to derive equivalent neutral wind is provided.

  10. Responsive Photonic Crystal Carbohydrate Hydrogel Sensor Materials for Selective and Sensitive Lectin Protein Detection.

    PubMed

    Cai, Zhongyu; Sasmal, Aniruddha; Liu, Xinyu; Asher, Sanford A

    2017-10-04

    Lectin proteins, such as the highly toxic lectin protein, ricin, and the immunochemically important lectin, jacalin, play significant roles in many biological functions. It is highly desirable to develop a simple but efficient method to selectively detect lectin proteins. Here we report the development of carbohydrate containing responsive hydrogel sensing materials for the selective detection of lectin proteins. The copolymerization of a vinyl linked carbohydrate monomer with acrylamide and acrylic acid forms a carbohydrate hydrogel that shows specific "multivalent" binding to lectin proteins. The resulting carbohydrate hydrogels are attached to 2-D photonic crystals (PCs) that brightly diffract visible light. This diffraction provides an optical readout that sensitively monitors the hydrogel volume. We utilize lactose, galactose, and mannose containing hydrogels to fabricate a series of 2-D PC sensors that show strong selective binding to the lectin proteins ricin, jacalin, and concanavalin A (Con A). This binding causes a carbohydrate hydrogel shrinkage which significantly shifts the diffraction wavelength. The resulting 2-D PC sensors can selectively detect the lectin proteins ricin, jacalin, and Con A. These unoptimized 2-D PC hydrogel sensors show a limit of detection (LoD) of 7.5 × 10(-8) M for ricin, a LoD of 2.3 × 10(-7) M for jacalin, and a LoD of 3.8 × 10(-8) M for Con A, respectively. This sensor fabrication approach may enable numerous sensors for the selective detection of numerous lectin proteins.

  11. IFCC educational materials on selected analytical and clinical applications of high sensitivity cardiac troponin assays.

    PubMed

    Apple, Fred S; Jaffe, Allan S; Collinson, Paul; Mockel, Martin; Ordonez-Llanos, Jordi; Lindahl, Bertil; Hollander, Judd; Plebani, Mario; Than, Martin; Chan, M H M

    2015-03-01

    In 2011, the IFCC Task Force on Clinical Applications of Cardiac Bio-Markers (TF-CB) was formed, with the purpose of providing evidence based educational materials to assist all biomarker users, i.e. laboratorians, clinicians, researchers, in-vitro diagnostics and regulatory agencies, in better understanding important analytical and clinical aspects of established and novel cardiac biomarkers for use in clinical practice and research. The goal of the task force was to promulgate the same information conjointly through the in vitro diagnostic industry to the laboratory, emergency department and cardiologists. The initial undertaking of the TF-CB, which is comprised of laboratory medicine scientists, emergency medicine physicians and cardiologists, was to address two key issues pertaining to implementing high-sensitivity cardiac troponin (hs-cTn) assays in clinical practice: the 99th percentile upper reference limit (URL) and calculating serial change values in accord with the Universal Definition of AMI. The highlights of both concepts from IFCC statements are described.

  12. Sensitive and Fast Humidity Sensor Based on A Redox Conducting Supramolecular Ionic Material for Respiration Monitoring.

    PubMed

    Yan, Hailong; Zhang, Li; Yu, Ping; Mao, Lanqun

    2017-01-03

    Real-time monitoring of respiratory rate (RR) is highly important for human health, clinical diagnosis, and fundamental scientific research. Exhaled humidity-based RR monitoring has recently attracted increased attention because of its accuracy and portability. Here, we report a new design of an exhaled humidity sensor for the real-time monitoring of the RR based on a synthetic redox conducting supramolecular ionic material (SIM). The humidity-dependent conducting SIM is prepared by ionic self-assembly in aqueous solutions of electroactive 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,10-bis(3-methylimidazolium-1-yl) decane (C10(mim)2). By taking full advantage of the high hygroscopicity and water stability arising from the ionic and hydrophobic interactions between two building blocks (i.e., ABTS and C10(mim)2), the SIM-based humidity sensor exhibits both high sensitivity (less than 0.1% relative humidity) and fast response time (∼37 ms). These excellent properties allow this humidity sensor to noninvasively monitor the RRs of not only humans but also rats that have a much faster RR and much smaller tidal volume than humans. Moreover, this sensor could also be efficiently used for the real-time monitoring of the recovery process of rats from anesthesia.

  13. Water and tissue equivalence properties of biological materials for photons, electrons, protons and alpha particles in the energy region 10 keV-1 GeV: a comparative study.

    PubMed

    Kurudirek, Murat

    2016-09-01

    To compare some biological materials in respect to the water and tissue equivalence properties for photon, electron, proton and alpha particle interactions as means of the effective atomic number (Zeff) and electron density (Ne). A Z-wise interpolation procedure has been adopted for calculation of Zeff using the mass attenuation coefficients for photons and the mass stopping powers for charged particles. At relatively low energies (100 keV-3 MeV), Zeff and Ne for photons and electrons were found to be constant while they vary much more for protons and alpha particles. In contrast, Zeff and Ne for protons and alpha particles were found to be constant after 3 MeV whereas for photons and electrons they were found to increase with the increasing energy. Also, muscle eq. liquid (with sucrose) have Zeff and Ne values close to the Muscle Skeletal (ICRP) and Muscle Striated (ICRU) within low relative differences below 9%. Muscle eq. liquid (without sucrose) have Zeff and Ne values close to the Muscle Skeletal (ICRP) and Muscle Striated (ICRU) with difference below 10%. The reported data should be useful in determining best water as well as tissue equivalent materials for photon, electron, proton and alpha particle interactions.

  14. Equivalent Dynamic Models.

    PubMed

    Molenaar, Peter C M

    2017-02-16

    Equivalences of two classes of dynamic models for weakly stationary multivariate time series are discussed: dynamic factor models and autoregressive models. It is shown that exploratory dynamic factor models can be rotated, yielding an infinite set of equivalent solutions for any observed series. It also is shown that dynamic factor models with lagged factor loadings are not equivalent to the currently popular state-space models, and that restriction of attention to the latter type of models may yield invalid results. The known equivalent vector autoregressive model types, standard and structural, are given a new interpretation in which they are conceived of as the extremes of an innovating type of hybrid vector autoregressive models. It is shown that consideration of hybrid models solves many problems, in particular with Granger causality testing.

  15. Amazingly resilient Indigenous people! Using transformative learning to facilitate positive student engagement with sensitive material.

    PubMed

    Jackson, Debra; Power, Tamara; Sherwood, Juanita; Geia, Lynore

    2013-12-01

    If health professionals are to effectively contribute to improving the health of Indigenous people, understanding of the historical, political, and social disadvantage that has lead to health disparity is essential. This paper describes a teaching and learning experience in which four Australian Indigenous academics in collaboration with a non-Indigenous colleague delivered an intensive workshop for masters level post-graduate students. Drawing upon the paedagogy of Transformative Learning, the objectives of the day included facilitating students to explore their existing understandings of Indigenous people, the impact of ongoing colonisation, the diversity of Australia's Indigenous people, and developing respect for alternative worldviews. Drawing on a range of resources including personal stories, autobiography, film and interactive sessions, students were challenged intellectually and emotionally by the content. Students experienced the workshop as a significant educational event, and described feeling transformed by the content, better informed, more appreciative of other worldviews and Indigenous resilience and better equipped to contribute in a more meaningful way to improving the quality of health care for Indigenous people. Where this workshop differs from other Indigenous classes was in the involvement of an Indigenous teaching team. Rather than a lone academic who can often feel vulnerable teaching a large cohort of non-Indigenous students, an Indigenous teaching team reinforced Indigenous authority and created an emotionally and culturally safe space within which students were allowed to confront and explore difficult truths. Findings support the value of multiple teaching strategies underpinned by the theory of transformational learning, and the potential benefits of facilitating emotional as well as intellectual student engagement when presenting sensitive material.

  16. Is gall-bladder polyp equivalent to cancer? An analysis of material from 1196 cholecystectomies--a comparison of the ultrasound and histopathological results.

    PubMed

    Maciejewski, Piotr; Strzelczyk, Janusz

    2014-05-01

    Polyps of the gall-bladder has long been a serious diagnostic problem. Their detection in routine ultrasound is not yet satisfactory and often does not allow you to select the proper method of operating the gall-bladder. The aim of the study was to assess the accuracy of ultrasound diagnosis of polypoid lesions of the gall-bladder through its verification by histopathology in patients treated with cholecystectomy. In the years 2010-2013, 1196 patients underwent surgery due to diseases of the gall-bladder at the Department of General and Transplant Surgery, Medical University in Łódź. The study evaluated the sensitivity of ultrasound in detecting polyps of the gallbladder and histopathological findings of the formulations investigated. Preoperative ultrasound examination (USG) revealed a polypoid lesion in 64 patients; only in 29 of them (44.6%) this diagnosis was confirmed by histopathological examination. In the other cases, cholecystolithiasis or inflammatory lesions were found. The most common histopathological findings included cholesterol polyps, adenomatous polyps, and inflammatory polyps. Malignant lesions (gall-bladder cancer) were found in five patients preoperatively diagnosed with a polypoid lesion, i.e 7.8% of patients preoperatively diagnosed with a polyp and 0.4% of all patients who received surgical treatment. Patients qualified for surgery due to polyps diagnosed by means of ultrasound examination constitued 5.4% of all patients who underwent cholecystectomy. On histopathological examination, the presence of polyps was confirmed in 2.4% patients treated with excision of the gall-bladder. Detection of gall-bladder polyp on ultrasound examination is an indication for cholecystectomy, in particular when the polyp diameter exceeds 10 mm. In each case of a polyp, cholecystolithiasis should also be taken into account and the presence (or absence) of indications for cholecystectomy should be discussed with the patient.

  17. Preventing UV-light damage of light sensitive materials using a highly protective UV-absorbing coating.

    PubMed

    Zayat, Marcos; Garcia-Parejo, Pilar; Levy, David

    2007-08-01

    One of the most important drawbacks of classical and new advanced functional materials for applications outdoors, or in environments with high UV irradiation, is the light induced damage that reduces drastically their effective operation lifetime or durability. This makes protecting light sensitive materials against UV irradiation a nowadays important technological demand in almost every industrial field. This tutorial review incorporates the main aspects of UV damage to materials and describes the recently developed highly effective thin UV-protective coatings, based on UV-absorber molecules entrapped in a Sol-Gel derived ormosil matrix.

  18. An all-solid-state perovskite-sensitized solar cell based on the dual function polyaniline as the sensitizer and p-type hole-transporting material

    NASA Astrophysics Data System (ADS)

    Xiao, Yaoming; Han, Gaoyi; Chang, Yunzhen; Zhou, Haihan; Li, Miaoyu; Li, Yanping

    2014-12-01

    High performance dual function of polyaniline (PANI) with brachyplast structure is synthesized by using a two-step cyclic voltammetry (CV) approach onto the fluorinated tin oxide (FTO) glass substrate, which acts as the sensitizer and p-type hole-transporting material (p-HTM) for the all-solid-state perovskite-sensitized solar cell (ass-PSSC) due to its π-π* transition and the localized polaron. The ass-PSSC based on the PANI delivers a photovoltaic conversion efficiency of 7.34%, and reduces from 7.34% to 6.71% after 1000 h, thereby 91.42% of the energy conversion efficiency is kept, indicating the device has a good long-term stability.

  19. Systematic survey of the dose enhancement in tissue-equivalent materials facing medium- and high-Z backscatterers exposed to X-rays with energies from 5 to 250 keV.

    PubMed

    Seidenbusch, M; Harder, D; Regulla, D

    2014-05-01

    The present study has been inspired by the results of earlier dose measurements in tissue-equivalent materials adjacent to thin foils of aluminum, copper, tin, gold, and lead. Large dose enhancements have been observed in low-Z materials near the interface when this ensemble was irradiated with X-rays of qualities known from diagnostic radiology. The excess doses have been attributed to photo-, Compton, and Auger electrons released from the metal surfaces. Correspondingly, high enhancements of biological effects have been observed in single cell layers arranged close to gold surfaces. The objective of the present work is to systematically survey, by calculation, the values of the dose enhancement in low-Z media facing backscattering materials with a variety of atomic numbers and over a large range of photon energies. Further parameters to be varied are the distance of the point of interest from the interface and the kind of the low-Z material. The voluminous calculations have been performed using the PHOTCOEF algorithm, a proven set of interpolation functions fitted to long-established Monte Carlo results, for primary photon energies between 5 and 250 keV and for atomic numbers varying over the periodic system up to Z = 100. The calculated results correlate well with our previous experimental results. It is shown that the values of the dose enhancement (a) vary strongly in dependence upon Z and photon energy; (b) have maxima in the energy region from 40 to 60 keV, determined by the K and L edges of the backscattering materials; and (c) are valued up to about 130 for "International Commission on Radiological Protection (ICRP) soft tissue" (soft tissue composition recommended by the ICRP) as the adjacent low-Z material. Maximum dose enhancement associated with the L edge occurs for materials with atomic numbers between 50 and 60, e.g., barium (Z = 56) and iodine (Z = 53). Such materials typically serve as contrast media in medical X-ray diagnostics. The gradual

  20. The material, morphological, and mechanical similarities between sensitive clay landslides and dry snow slab avalanches: Implications and applications

    NASA Astrophysics Data System (ADS)

    Gauthier, D.; Hutchinson, D. J.

    2012-04-01

    Recent research has suggested that certain similarities exist between the material properties, morphological expression, and mechanics of large landslides in sensitive clay soils (e.g. in Eastern Canada and Norway), and slab avalanches in dry seasonal snow (e.g. in Western Canada and Alpine countries). To further this concept, we review existing research, and highlight some previously unrecognized similarities between sensitive clay landslides and dry slab avalanches. For example, both snow and sensitive clay are highly porous with a meta-stable fabric or texture, show brittle yielding at high strain rates, and near complete loss of cohesion with extensive remoulding is observed in both. In both materials, yielding is structural and there is a corresponding volumetric collapse of the fabric following bond failure. Furthermore, slopes of sensitive clay and seasonal alpine snow are naturally layered, with variations grain size, density, stiffness, strength, etc., occurring over a variety of scales through the depth profile. Possible layering in both includes strong, thick strata overlying relatively thin, weak ones; these are primary features of the clay or snow, formed during deposition or by some subsequent metamorphic process that alters bonding or individual grains. Progressive failure in the fabric of a buried weak layer in snow leads to detachment of the overlying slab; this same process has been modeled successfully in sensitive clay. Observed triggering factors in sensitive clay landslides and slab avalanches include relatively minor, local loading, or some natural temporal material change acting on overlying layers, leading to a destabilization and failure in underlying layers. Slides are observed on very low angle or nearly flat slopes in both sensitive clay and snow. In both, bulk displacement or flow of the overlying snow or clay strata may not occur, despite an extensive basal failure. In those cases a large scale (e.g. 1-10 m) ribbed or 'thumbprint

  1. Nanostructured Zinc Oxide Materials for Use as Dye Sensitized Solar Cell Working Electrodes and Photocatalysts

    NASA Astrophysics Data System (ADS)

    Chang, Roger

    Since their invention in 1991, dye-sensitized solar cells (DSCs) have been the subject of intense research interest owing to their low cost, ease of manufacture and potential for low-light applications. In this thesis, the focus is on replacing TiO2 with ZnO, a semiconductor that exhibits much higher electron mobility. The shape of the ZnO nanomaterial is investigated in order to determine if shape and connectivity play a role in how best to exploit the high electron mobility of ZnO. When ZnO nanoparticles are replaced with 1-D nanowires in a DSC, it has been shown that electron transport is improved as measured by faster electron transport times and high electron diffusion coefficients. However, despite these electron transport advantages, ZnO nanowire-based DSCs still suffer from lower efficiencies than ZnO nanoparticle-based DSCs because of their much smaller surface area for dye loading. In the thesis work, zinc oxide nanorods are introduced as a compromise material that can maintain a large surface area, while taking advantage of 1-D fast electron transport. It is shown that by changing the shape of the semiconductor nanomaterial to elongated nanorods, electron transport time, electron lifetime, electron diffusivity and other measures of DSC performance are enhanced. Additionally, electrodeposition into hard templates was used to fabricate ZnO nanowires with magnetic Ni caps. The electrodeposited Ni-ZnO nanowires are shown to be useful in catalyzing the photodegradation of methylene blue (MB) , a model organic dye, and the result is compared to ZnO nanoparticles. The elongated shape of the nanowires is expected to prevent the aggregation that reduces the catalytic efficacy of ZnO nanoparticles, whereas the Ni segment is expected to enhance photocatalysis by increasing the production of radical hydroxide species that degrade the dye. Our experiments show that Ni-ZnO nanowires are more effective photocatalysts than ZnO nanoparticles as measured by the decrease

  2. Sensitivity analysis of the non-linear dynamic viscoplastic response of 2-d structures with respect to material parameters

    NASA Technical Reports Server (NTRS)

    Kulkarni, Makarand; Noor, Ahmed K.

    1995-01-01

    A computational procedure is presented for evaluating the sensitivity coefficients of the viscoplastic response of structures subjected to dynamic loading. A state of plane stress is assumed to exist in the structure, a velocity strain-Cauchy stress formulation is used, and the geometric non-linearities arising from large strains are incorporated. The Jaumann rate is used as a frame indifferent stress rate. The material model is chosen to be isothermal viscoplasticity, and an associated flow rule is used with a von Mises effective stress. The equations of motion emanating from a finite element semi-discretization are integrated using an explicit central difference scheme with an implicit stress update. The sensitivity coefficients are evaluated using a direct differentiation approach. Since the domain of integration is the current configuration, the sensitivity coefficients of the spatial derivatives of the shape functions must be included. Numerical results are presented for a thin plate with a central cutout subjected to an in-plane compressive loading. The sensitivity coefficients are generated by evaluating the derivatives of the response quantities with respect to Young's modulus, and two of the material parameters characterizing the viscoplastic response. Time histories of the response and sensitivity coefficients, and spatial distributions at selected times are presented.

  3. 46 CFR 199.09 - Equivalents.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., material, or lifesaving appliance or arrangement, the Commandant (CG-521) may accept any other fitting, material, or lifesaving appliance or arrangement that is at least as effective as that required by this part. The Commandant may require engineering evaluations and tests to determine the equivalent...

  4. Five Equivalent d Orbitals

    ERIC Educational Resources Information Center

    Pauling, Linus; McClure, Vance

    1970-01-01

    Amplifies and clarifies a previous paper on pyramidal d orbitals. Discusses two sets of pyramid d orbitals with respect to their maximum bond strength and their symmetry. Authors described the oblate and prolate pentagonal antiprisms arising from the two sets of five equivalent d orbitals. (RR)

  5. Equivalent Colorings with "Maple"

    ERIC Educational Resources Information Center

    Cecil, David R.; Wang, Rongdong

    2005-01-01

    Many counting problems can be modeled as "colorings" and solved by considering symmetries and Polya's cycle index polynomial. This paper presents a "Maple 7" program link http://users.tamuk.edu/kfdrc00/ that, given Polya's cycle index polynomial, determines all possible associated colorings and their partitioning into equivalence classes. These…

  6. Equivalent Colorings with "Maple"

    ERIC Educational Resources Information Center

    Cecil, David R.; Wang, Rongdong

    2005-01-01

    Many counting problems can be modeled as "colorings" and solved by considering symmetries and Polya's cycle index polynomial. This paper presents a "Maple 7" program link http://users.tamuk.edu/kfdrc00/ that, given Polya's cycle index polynomial, determines all possible associated colorings and their partitioning into equivalence classes. These…

  7. PATHOGEN EQUIVALENCY COMMITTEE (PEC)

    EPA Science Inventory

    The U.S. Environmental Protection Agency created the PEC in 1985 to make recommendations to EPA and State managers on the equivalency of unproven sewage sludge disinfection technologies/processes to either a Process to Significantly Reduce Pathogens (PSRP) or a Process to Further...

  8. PATHOGEN EQUIVALENCY COMMITTEE (PEC)

    EPA Science Inventory

    The U.S. Environmental Protection Agency created the PEC in 1985 to make recommendations to EPA and State managers on the equivalency of unproven sewage sludge disinfection technologies/processes to either a Process to Significantly Reduce Pathogens (PSRP) or a Process to Further...

  9. Experimental Evaluation of Equivalent-Fluid Models for Melamine Foam

    NASA Technical Reports Server (NTRS)

    Allen, Albert R.; Schiller, Noah H.

    2016-01-01

    Melamine foam is a soft porous material commonly used in noise control applications. Many models exist to represent porous materials at various levels of fidelity. This work focuses on rigid frame equivalent fluid models, which represent the foam as a fluid with a complex speed of sound and density. There are several empirical models available to determine these frequency dependent parameters based on an estimate of the material flow resistivity. Alternatively, these properties can be experimentally educed using an impedance tube setup. Since vibroacoustic models are generally sensitive to these properties, this paper assesses the accuracy of several empirical models relative to impedance tube measurements collected with melamine foam samples. Diffuse field sound absorption measurements collected using large test articles in a laboratory are also compared with absorption predictions determined using model-based and measured foam properties. Melamine foam slabs of various thicknesses are considered.

  10. Process Safety Management Applied to Scaleup of a Transfer System for Electrostatically Sensitive Materials

    DTIC Science & Technology

    1996-08-01

    i.e., a positive charge. This transfer of electrons is know as the Triboelectric Effect. The extent of this electron exchange is determined largely...by the location of the two materials in the Triboelectric Series. Materials toward the top of the Triboelectric Series have a propensity to lose...provides an infinite electron source. The materials to be used in this test were low on the Triboelectric Series and therefore gained electrons upon

  11. New Explosive Materials and Pyrotechnic Formulations with Improved Safety and Sensitivity Properties

    DTIC Science & Technology

    1996-08-01

    materials as they are aged. For TiHx/KClO4 materials the general stability reaction is as follows. 2TiHx + (1+0.25x) KClO4 ----> 2 TiO2 + (1+0.25x) KCL...Decomposition and function result in the inert reaction products- TiO2 , KCl, and water. Table 2 Energetic Material Properties Material Lead Lead Property Azide...development work has been done at Unidynamics/Phoenix, Inc., now Pacific Scientific Co ., Energy Dynamics Division, Chandler, Arizona under partial support from

  12. Full-sensitivity depth-resolved measurements of displacement fields inside weakly scattering materials using wavelength scanning interferometry

    NASA Astrophysics Data System (ADS)

    Ruiz, Pablo D.; Chakraborty, Semanti

    2012-10-01

    This paper extends Digital Speckle Pattern Interferometry into three dimensions. A Wavelength Scanning Interferometry (WSI) system is proposed which provides displacement fields inside the volume of semi-transparent scattering materials with high spatial resolution and three-dimensional displacement sensitivity. The main driver to develop such a system is the need to determine constitutive parameters (mainly elastic constants) of materials such as polymers and biological tissues so that their behavior can be modeled computationally. The sample is illuminated by three non-coplanar collimated beams around the observation direction. Sequences of two-dimensional interferograms are recorded while the frequency of the laser is tuned at a constant rate. Each pixel thus records and intensity signal which temporal frequency encodes the optical path difference between the illumination and reference beams for a particular point on the sample. Fourier transformation along the time axis reconstructs the magnitude and phase of the material's microstructure. Different optical paths along each illumination direction are required in order to separate or multiplex, in the frequency domain, the signals corresponding to each sensitivity vector. In this way, all the information required to reconstruct the location and the 3D displacement vector of scattering points within the volume in the material is recorded simultaneously. A controlled validation experiment is performed, which confirms the ability of the technique to provide three dimensional displacement distributions inside semitransparent scattering materials.

  13. Assessment of Heat Hazard during the Polymerization of Selected Light-Sensitive Dental Materials

    PubMed Central

    Herman, Katarzyna; Fita, Katarzyna; Dudek, Krzysztof; Kowalczyk-Zając, Małgorzata; Czajczyńska-Waszkiewicz, Agnieszka; Piesiak-Pańczyszyn, Dagmara; Kosior, Piotr

    2016-01-01

    Introduction. Polymerization of light-cured dental materials used for restoration of hard tooth tissue may lead to an increase in temperature that may have negative consequence for pulp vitality. Aim. The aim of this study was to determine maximum temperatures reached during the polymerization of selected dental materials, as well as the time that is needed for samples of sizes similar to those used in clinical practice to reach these temperatures. Materials and Methods. The study involved four composite restorative materials, one lining material and a dentine bonding agent. The polymerization was conducted with the use of a diode light-curing unit. The measurements of the external surface temperature of the samples were carried out using the Thermovision®550 thermal camera. Results. The examined materials significantly differed in terms of the maximum temperatures values they reached, as well as the time required for reaching the temperatures. A statistically significant positive correlation of the maximum temperature and the sample weight was observed. Conclusions. In clinical practice, it is crucial to bear in mind the risk of thermal damage involved in the application of light-cured materials. It can be reduced by using thin increments of composite materials. PMID:27840825

  14. Assessment of Heat Hazard during the Polymerization of Selected Light-Sensitive Dental Materials.

    PubMed

    Janeczek, Maciej; Herman, Katarzyna; Fita, Katarzyna; Dudek, Krzysztof; Kowalczyk-Zając, Małgorzata; Czajczyńska-Waszkiewicz, Agnieszka; Piesiak-Pańczyszyn, Dagmara; Kosior, Piotr; Dobrzyński, Maciej

    2016-01-01

    Introduction. Polymerization of light-cured dental materials used for restoration of hard tooth tissue may lead to an increase in temperature that may have negative consequence for pulp vitality. Aim. The aim of this study was to determine maximum temperatures reached during the polymerization of selected dental materials, as well as the time that is needed for samples of sizes similar to those used in clinical practice to reach these temperatures. Materials and Methods. The study involved four composite restorative materials, one lining material and a dentine bonding agent. The polymerization was conducted with the use of a diode light-curing unit. The measurements of the external surface temperature of the samples were carried out using the Thermovision®550 thermal camera. Results. The examined materials significantly differed in terms of the maximum temperatures values they reached, as well as the time required for reaching the temperatures. A statistically significant positive correlation of the maximum temperature and the sample weight was observed. Conclusions. In clinical practice, it is crucial to bear in mind the risk of thermal damage involved in the application of light-cured materials. It can be reduced by using thin increments of composite materials.

  15. STUDY OF THERMAL SENSITIVITY AND THERMAL EXPLOSION VIOLENCE OF ENERGETIC MATERIALS IN THE LLNL ODTX SYSTEM

    SciTech Connect

    HSU, P C; Hust, G; May, C; Howard, M; Chidester, S K; Springer, H K; Maienschein, J L

    2011-08-03

    Some energetic materials may explode at fairly low temperatures and the violence from thermal explosion may cause a significant damage. Thus it is important to understand the response of energetic materials to thermal insults for safe handling and storage of energetic materials. The One Dimensional Time to Explosion (ODTX) system at the Lawrence Livermore National Laboratory can measure times to explosion, lowest explosion temperatures, and determine kinetic parameters of energetic materials. Samples of different configurations can be tested in the system. The ODTX testing can also generate useful data for determining thermal explosion violence of energetic materials. We also performed detonation experiments of LX-10 in aluminum anvils to determine the detonation violence and validated the Zerilli Armstrong aluminum model. Results of the detonation experiments agreed well with the model prediction.

  16. Electron Beam Lithography Using Highly Sensitive Negative Type of Plant-Based Resist Material Derived from Biomass on Hardmask Layer

    NASA Astrophysics Data System (ADS)

    Takei, Satoshi; Oshima, Akihiro; Sekiguchi, Atsushi; Yanamori, Naomi; Kashiwakura, Miki; Kozawa, Takahiro; Tagawa, Seiichi

    2011-10-01

    We investigated electron beam (EB) lithography using a novel highly sensitive negative type of plant-based resist material derived from biomass on a hardmask layer for trilayer processes. The chemical design concept for using the plant-based resist material with glucose and dextrin derivatives was first demonstrated in the EB lithography. The 1 µm line patterning images with highly efficient crosslinking properties and low film thickness shrinkage were provided under specific process conditions of EB lithography. The results shown reveal that the alpha-linked disaccharide formed by a 1,1-glucoside bond between two glucose units in dextrin derivatives was an important factor in controlling the highly sensitive EB patterning and developer properties.

  17. Development of a versatile capacitive tactile sensor based on transparent flexible materials integrating an excellent sensitivity and a high resolution

    NASA Astrophysics Data System (ADS)

    Zhang, H. Z.; Tang, Q. Y.; Chan, Y. C.

    2012-06-01

    A versatile capacitive tactile sensor based on transparent flexible materials is developed in a simple and low-cost fabrication process. The sensor shows an excellent sensitivity (S=2.05 N-1), and is highly sensitive to the load as low as about 3 mN. Moreover, it exhibits a prominent resolution. The excellent device performance is attributed to the creative design of polydimethylsiloxane (PDMS) polymer layer, used as the structural material of the sensor, in which each sensing section acting as a sensor unit is a concave square with hemispheric micro-structured PDMS arrays. Meanwhile, other sections without any PDMS arrays serving as perfect natural wall-barriers can make each sensor unit separated effectively.

  18. Synthesis of one-molecule-thick single-crystalline nanosheets of energetic material for high-sensitive force sensor

    PubMed Central

    Yang, Guangcheng; Hu, Hailong; Zhou, Yong; Hu, Yingjie; Huang, Hui; Nie, Fude; Shi, Weimei

    2012-01-01

    Energetic material is a reactive substance that contains a great amount of potential energy, which is extremely sensitive to external stimuli like force. In this work, one-molecule-thick single-crystalline nanosheets of energetic material were synthesized. Very small force applied on the nanosheet proves to lead to the rotation of the tilted nitro groups, and subsequently change of current of the nanosheet. We apply this principle to design high-sensitive force sensor. A theoretical model of force-current dependence was established based on the nanosheets' molecular packing structure model that was well supported with the high resolution XPS, AFM analysis results. An ultra-low-force with range of several picoNewton to several nanoNewton can be measured by determination of corresponding current value. PMID:23019519

  19. Synthesis of zinc chlorophyll materials for dye-sensitized solar cell applications.

    PubMed

    Erten-Ela, Sule; Vakuliuk, Olena; Tarnowska, Anna; Ocakoglu, Kasim; Gryko, Daniel T

    2015-01-25

    To design sensitizers for dye sensitized solar cells (DSSCs), a series of zinc chlorins with different substituents were synthesized. Novel zinc methyl 3-devinyl-3-hydroxymethyl-20-phenylacetylenylpyropheophorbide-a (ZnChl-1), zinc methyl 20-bromo-3-devinyl-3-hydroxymethylpyropheophorbide-a (ZnChl-2), zinc methyl 3-devinyl-3-hydroxymethyl-pyropheophorbide-a (ZnChl-3), zinc propyl 3-devinyl-3-hydroxymethyl-pyropheophorbide-a (ZnChl-4) were synthesized and their photovoltaic performances were evaluated in dye-sensitized solar cells. Photoelectrodes with a 7 μm thick nanoporous layer and a 5 μm thick light-scattering layer were used to fabricate dye sensitized solar cells. The best efficiency was obtained with ZnChl-2 sensitizer. ZnChl-2 gave a Jsc of 3.5 mA/cm(2), Voc of 412 mV, FF of 0.56 and an overall conversion efficiency of 0.81 at full sun (1000 W m(-2)).

  20. Wurtzite copper-zinc-tin sulfide as a superior counter electrode material for dye-sensitized solar cells

    PubMed Central

    2013-01-01

    Wurtzite and kesterite Cu2ZnSnS4 (CZTS) nanocrystals were employed as counter electrode (CE) materials for dye-sensitized solar cells (DSSCs). Compared to kesterite CZTS, the wurtzite CZTS exhibited higher electrocatalytic activity for catalyzing reduction of iodide electrolyte and better conductivity. Accordingly, the DSSC with wurtzite CZTS CE generated higher power conversion efficiency (6.89%) than that of Pt (6.23%) and kesterite CZTS (4.89%) CEs. PMID:24191954

  1. Establishing Substantial Equivalence: Metabolomics

    NASA Astrophysics Data System (ADS)

    Beale, Michael H.; Ward, Jane L.; Baker, John M.

    Modern ‘metabolomic’ methods allow us to compare levels of many structurally diverse compounds in an automated fashion across a large number of samples. This technology is ideally suited to screening of populations of plants, including trials where the aim is the determination of unintended effects introduced by GM. A number of metabolomic methods have been devised for the determination of substantial equivalence. We have developed a methodology, using [1H]-NMR fingerprinting, for metabolomic screening of plants and have applied it to the study of substantial equivalence of field-grown GM wheat. We describe here the principles and detail of that protocol as applied to the analysis of flour generated from field plots of wheat. Particular emphasis is given to the downstream data processing and comparison of spectra by multivariate analysis, from which conclusions regarding metabolome changes due to the GM can be assessed against the background of natural variation due to environment.

  2. Sterilization of heat-sensitive silicone implant material by low-pressure gas plasma.

    PubMed

    Hauser, Joerg; Esenwein, Stefan-Alexander; Awakowicz, Peter; Steinau, Hans-Ulrich; Köller, Manfred; Halfmann, Helmut

    2011-01-01

    In recent years, plasma treatment of medical devices and implant materials has gained more and more acceptance. Inactivation of microorganisms by exposure to ultraviolet (UV) radiation produced by plasma discharges and sterilization of medical implants and instruments is one possible application of this technique. The aim of this study was to evaluate the effectiveness of this sterilization technique on silicone implant material. Bacillus atrophaeus spores (10(6) colony-forming units [CFUs]) were sprayed on the surfaces of 12 silicone implant material samples. Four plasma sets with different gas mixtures (argon [Ar], argon-oxygen [Ar:O(2)], argon-hydrogen [Ar:H(2)] and argon-nitrogen [Ar:N(2)]) were tested for their antimicrobial properties. Post-sterilization mechanical testing of the implant material was performed in order to evaluate possible plasma-induced structural damage. The inductively coupled low-pressure plasma technique can achieve fast and efficient sterilization of silicone implant material without adverse materials effects. All four gas mixtures led to a significant spore reduction, and no structural damage to the implant material could be observed.

  3. Obtaining an equivalent beam

    NASA Technical Reports Server (NTRS)

    Butler, Thomas G.

    1990-01-01

    In modeling a complex structure the researcher was faced with a component that would have logical appeal if it were modeled as a beam. The structure was a mast of a robot controlled gantry crane. The structure up to this point already had a large number of degrees of freedom, so the idea of conserving grid points by modeling the mast as a beam was attractive. The researcher decided to make a separate problem of of the mast and model it in three dimensions with plates, then extract the equivalent beam properties by setting up the loading to simulate beam-like deformation and constraints. The results could then be used to represent the mast as a beam in the full model. A comparison was made of properties derived from models of different constraints versus manual calculations. The researcher shows that the three-dimensional model is ineffective in trying to conform to the requirements of an equivalent beam representation. If a full 3-D plate model were used in the complete representation of the crane structure, good results would be obtained. Since the attempt is to economize on the size of the model, a better way to achieve the same results is to use substructuring and condense the mast to equivalent end boundary and intermediate mass points.

  4. Effects of culture-sensitive adaptation of patient information material on usefulness in migrants: a multicentre, blinded randomised controlled trial

    PubMed Central

    Hölzel, Lars P; Ries, Zivile; Kriston, Levente; Dirmaier, Jörg; Zill, Jördis M; Rummel-Kluge, Christine; Niebling, Wilhelm; Bermejo, Isaac; Härter, Martin

    2016-01-01

    Objectives To evaluate the usefulness of culture-sensitive patient information material compared with standard translated material. Design Multicentre, double-blind randomised controlled trial. Setting 37 primary care practices. Participants 435 adult primary care patients with a migration background with unipolar depressive disorder or non-specific chronic low back pain were randomised. Patients who were unable to read in the language of their respective migration background were excluded. Sufficient data were obtained from 203 women and 106 men. The largest group was of Russian origin (202 patients), followed by those of Turkish (52), Polish (30) and Italian (25) origin. Interventions Intervention group: provision of culture-sensitive adapted material. Control group: provision of standard translated material. Main outcome measures Primary outcome: patient-rated usefulness (USE) assessed immediately after patients received the material. Secondary outcomes: patient-rated usefulness after 8 weeks and 6 months, symptoms of depression (PHQ-9), back pain (Back Pain Core Set) and quality of life (WHO-5) assessed at all time points. Results Usefulness was found to be significantly higher (t=1.708, one-sided p=0.04) in the intervention group (USE-score=65.08, SE=1.43), compared with the control group (61.43, SE=1.63), immediately after patients received the material, in the intention-to-treat analysis, with a mean difference of 3.65 (one-sided 95% lower confidence limit=0.13). No significant differences were found for usefulness at follow-up (p=0.16, p=0.71). No significant effect was found for symptom severity in depression (p=0.95, p=0.66, p=0.58), back pain (p=0.40, p=0.45, p=0.32) or quality of life (p=0.76, p=0.86, p=0.21), either immediately after receiving the material, or at follow-up (8 weeks; 6 months). Patients with a lower level of dominant society immersion benefited substantially and significantly more from the intervention than patients with a high

  5. Effects of culture-sensitive adaptation of patient information material on usefulness in migrants: a multicentre, blinded randomised controlled trial.

    PubMed

    Hölzel, Lars P; Ries, Zivile; Kriston, Levente; Dirmaier, Jörg; Zill, Jördis M; Rummel-Kluge, Christine; Niebling, Wilhelm; Bermejo, Isaac; Härter, Martin

    2016-11-23

    To evaluate the usefulness of culture-sensitive patient information material compared with standard translated material. Multicentre, double-blind randomised controlled trial. 37 primary care practices. 435 adult primary care patients with a migration background with unipolar depressive disorder or non-specific chronic low back pain were randomised. Patients who were unable to read in the language of their respective migration background were excluded. Sufficient data were obtained from 203 women and 106 men. The largest group was of Russian origin (202 patients), followed by those of Turkish (52), Polish (30) and Italian (25) origin. Intervention group: provision of culture-sensitive adapted material. provision of standard translated material. Primary outcome: patient-rated usefulness (USE) assessed immediately after patients received the material. patient-rated usefulness after 8 weeks and 6 months, symptoms of depression (PHQ-9), back pain (Back Pain Core Set) and quality of life (WHO-5) assessed at all time points. Usefulness was found to be significantly higher (t=1.708, one-sided p=0.04) in the intervention group (USE-score=65.08, SE=1.43), compared with the control group (61.43, SE=1.63), immediately after patients received the material, in the intention-to-treat analysis, with a mean difference of 3.65 (one-sided 95% lower confidence limit=0.13). No significant differences were found for usefulness at follow-up (p=0.16, p=0.71). No significant effect was found for symptom severity in depression (p=0.95, p=0.66, p=0.58), back pain (p=0.40, p=0.45, p=0.32) or quality of life (p=0.76, p=0.86, p=0.21), either immediately after receiving the material, or at follow-up (8 weeks; 6 months). Patients with a lower level of dominant society immersion benefited substantially and significantly more from the intervention than patients with a high level of immersion (p=0.005). Cultural adaptation of patient information material provides benefits over high quality

  6. Development of Novel Polymeric Materials for Gene Therapy and pH-Sensitive Drug Delivery: Modeling, Synthesis, Characterization, and Analysis

    SciTech Connect

    Anderson, Brian Curtis

    2002-01-01

    The underlying theme of this thesis is the use of polymeric materials in bioapplications. Chapters 2-5 either develop a fundamental understanding of current materials used for bioapplications or establish protocols and procedures used in characterizing and synthesizing novel materials. In chapters 6 and 7 these principles and procedures are applied to the development of materials to be used for gene therapy and drug delivery. Chapter one is an introduction to the ideas that will be necessary to understand the subsequent chapters, as well as a literature review of these topics. Chapter two is a paper that has been published in the ''Journal of Controlled Release'' that examines the mechanism of drug release from a polymer gel, as well as experimental design suggestions for the evaluation of water soluble drug delivery systems. Chapter three is a paper that has been published in the ''Journal of Pharmaceutical Sciences'' that discusses the effect ionic salts have on properties of the polymer systems examined in chapter two. Chapter four is a paper published in the Materials Research Society Fall 2000 Symposium Series dealing with the design and synthesis of a pH-sensitive polymeric drug delivery device. Chapter five is a paper that has been published in the journal ''Biomaterials'' proposing a novel polymer/metal composite for use as a biomaterial in hip arthroplasty surgery. Chapter six is a paper that will appear in an upcoming volume of the Journal ''Biomaterials'' dealing with the synthesis of a novel water soluble cationic polymer with possible applications in non-viral gene therapy. Chapter seven is a paper that has been submitted to ''Macromolecules'' discussing several novel block copolymers based on poly(ethylene glycol) and poly(diethylamino ethyl methacrylate) that possess both pH-sensitive and temperature sensitive properties. Chapter eight contains a summary of the research contained in chapters 2-7 and proposes future research for the gene therapy and

  7. Study of thermal sensitivity and thermal explosion violence of energetic materials in the LLNL ODTX system

    NASA Astrophysics Data System (ADS)

    Hsu, P. C.; Hust, G.; Zhang, M. X.; Lorenz, T. K.; Reynolds, J. G.; Fried, L.; Springer, H. K.; Maienschein, J. L.

    2014-05-01

    Incidents caused by fire and combat operations can heat energetic materials that may lead to thermal explosion and result in structural damage and casualty. Some explosives may thermally explode at fairly low temperatures (< 100 °C) and the violence from thermal explosion may cause significant damage. Thus it is important to understand the response of energetic materials to thermal insults. The One Dimensional Time to Explosion (ODTX) system at the Lawrence Livermore National Laboratory has been used for decades to measure times to explosion, threshold thermal explosion temperature, and determine kinetic parameters of energetic materials. Samples of different configurations (pressed part, powder, paste, and liquid) can be tested in the system. The ODTX testing can also provide useful data for assessing the thermal explosion violence of energetic materials. Recent ODTX experimental data are reported in the paper.

  8. Airtight container for the transfer of atmosphere-sensitive materials into vacuum-operated characterization instruments

    SciTech Connect

    Gaume, Romain M.; Joubert, Lydia-Marie

    2011-12-15

    This paper describes the design and operation of a simple airtight container devised to facilitate the transfer of atmosphere-sensitive samples from a glovebox to the vacuum chamber of an analytical instrument such as a scanning electron microscope. The use of this device for characterizing the microstructure of highly hygroscopic strontium iodide ceramics by scanning electron microscopy is illustrated as an application example.

  9. Dye-sensitized solar cells based on multichromophoric supramolecular light-harvesting materials.

    PubMed

    Panda, Dillip K; Goodson, Flynt S; Ray, Shuvasree; Saha, Sourav

    2014-05-25

    Multichromophoric dye-sensitized solar cells (DSSCs) comprised of a supramolecular zinc-phthalocyanineperyleneimide (ZnPc···PMI) dyad convert light to electrical energy with much higher power conversion efficiency (PCE = 2.3%) and incident-photon-to-current-efficiency (IPCE = ca. 40%) than the devices made of individual dyes.

  10. Decay Kinetics of UV-Sensitive Materials: An Introductory Chemistry Experiment

    ERIC Educational Resources Information Center

    Via, Garrhett; Williams, Chelsey; Dudek, Raymond; Dudek, John

    2015-01-01

    First-order kinetic decay rates can be obtained by measuring the time-dependent reflection spectra of ultraviolet-sensitive objects as they returned from their excited, colored state back to the ground, colorless state. In this paper, a procedure is described which provides an innovative and unique twist on standard, undergraduate, kinetics…

  11. Decay Kinetics of UV-Sensitive Materials: An Introductory Chemistry Experiment

    ERIC Educational Resources Information Center

    Via, Garrhett; Williams, Chelsey; Dudek, Raymond; Dudek, John

    2015-01-01

    First-order kinetic decay rates can be obtained by measuring the time-dependent reflection spectra of ultraviolet-sensitive objects as they returned from their excited, colored state back to the ground, colorless state. In this paper, a procedure is described which provides an innovative and unique twist on standard, undergraduate, kinetics…

  12. Organic particulate material levels in the atmosphere: conditions favoring sensitivity to varying relative humidity and temperature.

    PubMed

    Pankow, James F

    2010-04-13

    This study examines the sensitivity in predicted levels of atmospheric organic particulate matter (M(o), microg m(-3)) as those levels may potentially be affected by changes in relative humidity and temperature. In a given system, for each partitioning compound, f(g) and f(p) represent the gaseous and particulate fractions (f(g) + f(p) = 1). Sensitivity in the M(o) levels becomes dampened as the compounds contributing significantly to M(o) are increasingly found in the particle phase (f(p) --> 1). Thus, although local maxima in sensitivity can be encountered as M(o) levels increase, because as M(o) increases each f(p) --> 1, then increasing M(o) levels generally tend to reduce sensitivity in M(o) levels to changes in relative humidity and temperature. Experiments designed to elucidate the potential magnitudes of the effects of relative humidity and temperature on M(o) levels must be carried out at M(o) levels that are relevant for the ambient atmosphere: The f(p) values for the important partitioning compounds must not be elevated above ambient-relevant values. Systems in which M(o) levels are low (e.g., 1-2 microg m(-3)) and/or composed of unaged secondary organic aerosol are the ones most likely to show sensitivity to changing relative humidity and temperature. Results from two published chamber studies are examined in the above regard: [Warren B, et al. (2009) Atmos Environ 43:1789-1795] and [Prisle NL, et al. (2010) Geophys Res Lett 37:L01802].

  13. Patient-specific spine models. Part 1: Finite element analysis of the lumbar intervertebral disc--a material sensitivity study.

    PubMed

    Fagan, M J; Julian, S; Siddall, D J; Mohsen, A M

    2002-01-01

    If patient-specific finite element models of the spine could be developed, they would offer enormous opportunities in the diagnosis and management of back problems. Several generic models have been developed in the past, but there has been very little detailed examination of the sensitivity of these models' characteristics to the input parameters. This relationship must be thoroughly understood if representative patient-specific models are to be realized and used with confidence. In particular, the performance of the intervertebral discs are central to any spine model and need detailed investigation first. A generic non-linear model of an intervertebral disc was developed and subjected to compressive, flexion and torsional loading regimes. The effects of both material and geometric non-linearities were investigated for the three loading schemes and the results compared with experimental data. The basic material properties of the fibres, annulus and nucleus were then varied and the effects on the stiffness, annulus bulge and annulus stresses analysed. The results showed that the non-linear geometry assumption had a significant effect on the compression characteristics, whereas the non-linear material option did not. In contrast, the material non-linearity was more important for the flexural and torsional loading schemes. Thus, the inclusion of non-linear material and geometry analysis options in finite element models of intervertebral discs is necessary to predict in vivo load-deflection characteristics accurately. When the influence of the material properties was examined in detail, it was found that the fibre properties did not have a significant effect on the compressive stiffness of the disc but did affect the flexural and torsional stiffnesses by up to +/-20 per cent. All loading modes were sensitive to the annulus properties with stiffnesses varying by up to +/-16 per cent. The model also revealed that for a particular compressive deformation or flexural or

  14. Carbonaceous materials and their advances as a counter electrode in dye-sensitized solar cells: challenges and prospects.

    PubMed

    Kouhnavard, Mojgan; Ludin, Norasikin Ahmad; Ghaffari, Babak V; Sopian, Kamarozzaman; Ikeda, Shoichiro

    2015-05-11

    Dye-sensitized solar cells (DSSCs) serve as low-costing alternatives to silicon solar cells because of their low material and fabrication costs. Usually, they utilize Pt as the counter electrode (CE) to catalyze the iodine redox couple and to complete the electric circuit. Given that Pt is a rare and expensive metal, various carbon materials have been intensively investigated because of their low costs, high surface areas, excellent electrochemical stabilities, reasonable electrochemical activities, and high corrosion resistances. In this feature article, we provide an overview of recent studies on the electrochemical properties and photovoltaic performances of carbon-based CEs (e.g., activated carbon, nanosized carbon, carbon black, graphene, graphite, carbon nanotubes, and composite carbon). We focus on scientific challenges associated with each material and highlight recent advances achieved in overcoming these obstacles. Finally, we discuss possible future directions for this field of research aimed at obtaining highly efficient DSSCs.

  15. ORNL IntelligentFreight Initiative:Enhanced End-to-End Supply Chain Visibility of Security Sensitive Hazardous Materials

    SciTech Connect

    Walker, Randy M.; Shankar, Mallikarjun; Gorman, Bryan L.

    2009-01-01

    In the post September 11, 2001 (9/11) world the federal government has increased its focus on the manufacturing, distributing, warehousing, and transporting of hazardous materials. In 2002, Congress mandated that the Transportation Security Agency (TSA) designate a subset of hazardous materials that could pose a threat to the American public when transported in sufficiently large quantities. This subset of hazardous materials, which could be weaponized or subjected to a nefarious terrorist act, was designated as Security Sensitive Hazardous Materials (SSHM). Radioactive materials (RAM) were of special concern because actionable intelligence had revealed that Al Qaeda desired to develop a homemade nuclear device or a dirty bomb to use against the United States (US) or its allies.1 Because of this clear and present danger, it is today a national priority to develop and deploy technologies that will provide for visibility and real-time exception notification of SSHM and Radioactive Materials in Quantities of Concern (RAMQC) in international commerce. Over the past eight years Oak Ridge National Laboratory (ORNL) has been developing, implementing, and deploying sensor-based technologies to enhance supply chain visibility. ORNL s research into creating a model for shipments, known as IntelligentFreight, has investigated sensors and sensor integration methods at numerous testbeds throughout the national supply chain. As a result of our research, ORNL believes that most of the information needed by supply chain partners to provide shipment visibility and exceptions-based reporting already exists but is trapped in numerous proprietary or agency-centric databases.

  16. A sensitive optode membrane for berberine using conjugated polymer as sensing material.

    PubMed

    Huang, Hong-Mei; Wang, Ke-Min; Yang, Rong-Hua; Yang, Xiao-Hai; Huang, Sha-Sheng; Xiao, Dan; Feng, Feng

    2002-10-01

    A new optode membrane for the sensitive determination of berberine based on fluorescence quenching of a conjugated polymer, poly(2,5-dimethoxy-phenyldiacetylene) (PDPA), is proposed. Incorporated in a membrane composed of plasticized poly(vinyl chloride) (PVC), the conjugated polymer exhibits better stability than those small sensing molecules regarding its excellent optical properties and lipophilic characteristics. Moreover, upon the introduction of a negatively charged lipophilic additive (tetraphenylborate salt) into a PVC membrane, the optode displayed enhanced sensitivity. In addition, satisfactory analytical sensing characteristics for determining beberine were obtained in terms of the selectivity, reversibility and reproducibility with a detecting range of between 7.5 x 10(-7) mol l(-1) and 7.5 x 10(-4) mol l(-1). The optode membrane has been applied to determine berberine in commercial tablets. The results showed a good agreement with those obtained by the pharmacopoeial method.

  17. Sensitivity analysis of roll load, torque and material properties in the roll forming process

    NASA Astrophysics Data System (ADS)

    Abeyrathna, Buddhika; Rolfe, Bernard; Hodgson, Peter; Weiss, Matthias

    2013-12-01

    Advanced High Strength Steel (AHSS) and Ultra High Strength Steel (UHSS) are increasingly used in the current automotive industry because of their high strength and weight saving potential. As a sheet forming process, roll forming is capable of forming such materials with precise dimensions, however a small change in processing may results in significant change in the material properties such as yield strength and hardening exponent from coil to coil or within the same coil. This paper presents the effect of yield strength and the hardening exponent on roll load, torque of the roll forming process and the longitudinal bow. The roll forming process is numerically simulated, and then the regression analysis and Analysis of Variance (ANOVA) techniques are employed to establish the relationships among the aforementioned parameters and to determine the percentage influence of material properties on longitudinal bow, roll load and torque.

  18. Spectral Sensitization of Dichromated Gelatin (DCG) for an Improved Holographic Material.

    DTIC Science & Technology

    1981-04-01

    in its reduced ( leuco ) form. The reduction of the dye resulted from the interaction of the photo- excited dye , in its lowest triplet state, with...WORDS (Continue on reverse *Ida If neco..ry ed Identlly by block number) |tolography Triplet sensitizers Lasers Phase holograms Dichromated gelatin Dyes ...discussions onl dyes and photoimaging. Accession For NTIS mi’A&I 11V 1 Dis CONTENTS Section Title Page PREFACE iii TABLES v I INTRODUCTION I 1I

  19. Improving the sensitivity of J coupling measurements in solids with application to disordered materials

    SciTech Connect

    Guerry, Paul; Brown, Steven P.; Smith, Mark E.

    2016-05-15

    It has been shown previously that for magic angle spinning (MAS) solid state NMR the refocused INADEQUATE spin-echo (REINE) experiment can usefully quantify scalar (J) couplings in disordered solids. This paper focuses on the two z filter components in the original REINE pulse sequence, and investigates by means of a product operator analysis and fits to density matrix simulations the effects that their removal has on the sensitivity of the experiment and on the accuracy of the extracted J couplings. The first z filter proves unnecessary in all the cases investigated here and removing it increases the sensitivity of the experiment by a factor ∼1.1–2.0. Furthermore, for systems with broad isotropic chemical shift distributions (namely whose full widths at half maximum are greater than 30 times the mean J coupling strength), the second z filter can also be removed, thus allowing whole-echo acquisition and providing an additional √2 gain in sensitivity. Considering both random and systematic errors in the values obtained, J couplings determined by fitting the intensity modulations of REINE experiments carry an uncertainty of 0.2–1.0 Hz (∼1−10 %).

  20. Thermal performance sensitivity studies in support of material modeling for extended storage of used nuclear fuel

    SciTech Connect

    Cuta, Judith M.; Suffield, Sarah R.; Fort, James A.; Adkins, Harold E.

    2013-08-15

    The work reported here is an investigation of the sensitivity of component temperatures of a storage system, including fuel cladding temperatures, in response to age-related changes that could degrade the design-basis thermal behavior of the system. Three specific areas of interest were identified for this study. • degradation of the canister backfill gas from pure helium to a mixture of air and helium, resulting from postulated leakage due to stress corrosion cracking (SCC) of canister welds • changes in surface emissivity of system components, resulting from corrosion or other aging mechanisms, which could cause potentially significant changes in temperatures and temperature distributions, due to the effect on thermal radiation exchange between components • changes in fuel and basket temperatures due to changes in fuel assembly position within the basket cells in the canister The purpose of these sensitivity studies is to provide a realistic example of how changes in the physical properties or configuration of the storage system components can affect temperatures and temperature distributions. The magnitudes of these sensitivities can provide guidance for identifying appropriate modeling assumptions for thermal evaluations extending long term storage out beyond 50, 100, 200, and 300 years.

  1. The oxygen sensitivity/compatibility ranking of several materials by different test methods

    NASA Technical Reports Server (NTRS)

    Lockhart, Billy J.; Bryan, Coleman J.; Hampton, Michael D.

    1989-01-01

    Eleven materials were evaluated for oxygen compatibility using the following test methods: heat of combustion (ASTM D 2015), liquid oxygen impact (ASTM D 2512), pneumatic impact (ASTM G 74), gaseous mechanical impact (ASTM G 86), autogenous ignition temperature by pressurized differential scanning calorimeter, and the determination of the 50 percent reaction level in liquid oxygen using silicon carbide as a reaction enhancer. The eleven materials evaluated were: Teflon TFE, Vespel SP-21, Krytox 240AC, Viton PLV5010B, Fluorel E2160, Kel F 81, Fluorogold, Fluorogreen E-600, Rulon A, Garlock 8573, nylon 6/6.

  2. A magnetic-piezoelectric smart material-structure utilizing magnetic force interaction to optimize the sensitivity of current sensing

    NASA Astrophysics Data System (ADS)

    Yeh, Po-Chen; Chung, Tien-Kan; Lai, Chen-Hung; Wang, Chieh-Min

    2016-01-01

    This paper presents a magnetic-piezoelectric smart material-structure using a novel magnetic-force-interaction approach to optimize the sensitivity of conventional piezoelectric current sensing technologies. The smart material-structure comprises a CuBe-alloy cantilever beam, a piezoelectric PZT sheet clamped to the fixed end of the beam, and an NdFeB permanent magnet mounted on the free end of the beam. When the smart material-structure is placed close to an AC conductor, the magnet on the beam of the smart structure experiences an alternating magnetic attractive and repulsive force produced by the conductor. Thus, the beam vibrates and subsequently generates a strain in the PZT sheet. The strain produces a voltage output because of the piezoelectric effect. The magnetic force interaction is specifically enhanced through the optimization approach (i.e., achieved by using SQUID and machining method to reorient the magnetization to different directions to maximize the magnetic force interaction). After optimizing, the beam's vibration amplitude is significantly enlarged and, consequently, the voltage output is substantially increased. The experimental results indicated that the smart material-structure optimized by the proposed approach produced a voltage output of 4.01 Vrms with a sensitivity of 501 m Vrms/A when it was placed close to a conductor with a current of 8 A at 60 Hz. The optimized voltage output and sensitivity of the proposed smart structure were approximately 316 % higher than those (1.27 Vrms with 159 m Vrms/A) of representative piezoelectric-based current sensing technologies presented in other studies. These improvements can significantly enable the development of more self-powered wireless current sensing applications in the future.

  3. Materials-of-Construction Radiation Sensitivity for a Fission Surface Power Convertor

    NASA Technical Reports Server (NTRS)

    Bowman, Cheryl L.; Geng, Steven M.; Niedra, Janis M.; Sayir, Ali; Shin, Eugene E.; Sutter, James K.; Thieme, Lanny G.

    2007-01-01

    A fission reactor combined with a free-piston Stirling convertor is one of many credible approaches for producing electrical power in space applications. This study assumes dual-opposed free-piston Stirling engines/linear alternators that will operate nominally at 825 K hot-end and 425 K cold-end temperatures. The baseline design options, temperature profiles, and materials of construction discussed here are based on historical designs as well as modern convertors operating at lower power levels. This notional design indicates convertors primarily made of metallic components that experience minimal change in mechanical properties for fast neutron fluences less than 10(sup 20) neutrons per square centimeter. However, these radiation effects can impact the magnetic and electrical properties of metals at much lower fluences than are crucial for mechanical property integrity. Moreover, a variety of polymeric materials are also used in common free-piston Stirling designs for bonding, seals, lubrication, insulation and others. Polymers can be affected adversely by radiation doses as low as 10(sup 5) - 10(sup 10) rad. Additionally, the absorbing dose rate, radiation hardness, and the resulting effect (either hardening or softening) varies depending on the nature of the particular polymer. The classes of polymers currently used in convertor fabrication are discussed along possible substitution options. Thus, the materials of construction of prototypic Stirling convertor engines have been considered and the component materials susceptible to damage at the lowest neutron fluences have been identified.

  4. IR and green femtosecond laser machining of heat sensitive materials for medical devices at micrometer scale

    NASA Astrophysics Data System (ADS)

    Stolberg, Klaus; Friedel, Susanna; Kremser, Bert; Roehner, Markus

    2014-03-01

    In medical device manufacturing there is an increasing interest to enhance machining of biocompatible materials on a micrometer scale. Obviously there is a trend to generate smaller device structures like cavities, slits or total size of the device to address new applications. Another trend points to surface modification, which allows controlling selective growth of defined biological cell types on medical implants. In both cases it is interesting to establish machining methods with minimized thermal impact, because biocompatible materials often show degradation of mechanical properties under thermal treatment. Typical examples for this effect is embrittlement of stainless steel at the edge of a cutting slit, which is caused by oxidation and phase change. Also for Nitinol (NiTi alloy) which is used as another stent material reduction of shape-memory behavior is known if cutting temperature is too high. For newest biodegradable materials like Polylactic acid (PLA) based polymers, lowest thermal impact is required due to PLA softening point (65°C) and melting temperature (~170 °C ). Laser machining with ultra-short pulse lasers is a solution for this problem. In our work we demonstrate a clean laser cut of NiTi and PLA based polymers with a high repetition-rate 1030 nm, 400-800 fs laser source at a pulse energy of up to 50 μJ and laser repetition rate of up to 500 kHz.

  5. The sensitivity of energetic materials to friction, impact, and electrostatic stimuli

    SciTech Connect

    Vannet, M.D.

    1992-09-24

    Friction, impact, and electrostatic tests were conducted on materials that had not previously been tested at Mound, including PETN, BTF, HNS-IV, and pyrotechnic and thermite powders. Results are presented. Tables and charts including previous results are also included. 6 figs, 8 refs, 8 tabs.

  6. The sensitivity of energetic materials to friction, impact, and electrostatic stimuli

    SciTech Connect

    Vannet, M.D.

    1992-09-24

    Friction, impact, and electrostatic tests were conducted on materials that had not previously been tested at Mound, including PETN, BTF, HNS-IV, and pyrotechnic and thermite powders. Results are presented. Tables and charts including previous results are also included. 6 figs, 8 refs, 8 tabs.

  7. Dual Functional TiO2-Au Nanocomposite Material for Solid-State Dye-Sensitized Solar Cells.

    PubMed

    Pandikumar, A; Suresh, S; Murugesan, S; Ramaraj, R

    2015-09-01

    Titanium dioxide-gold nanocomposite ((TiO2-Au)(nps)) materials dispersed in poly(diallyldimethylammonium chloride) (PDDA) polymer electrolyte are employed as solid-state electrolytes in a dye-sensitized solar cell (DSSC) containing nanocrystalline TiO2 nanoparticle (P25) or (P25-Au)(nps) thin film photoanode adsorbed with a near-IR dye sensitizer, nickel-phthalocyanine (NiPcTs). The photocurrent-photovoltage characteristics of the DSSCs are evaluated under standard AM 1.5 G simulated solar irradiation of 100 mW/cm2. The (TiO2-Au)(nps) nanocomposite material incorporated into the PDDA polymer electrolyte promotes interfacial charge transfer process, reduces crystallinity of the polymer electrolyte and enhances mobility of the /-/I3- redox couple, which are resulted in -6-fold increase in the overall solar to electrical energy conversion efficiency when compared to the unmodified polymer electrolyte based DSSC. When the P25 photoanode is replaced with the (P25-Au)(nps) photoanode, a further 8-fold increase in the overall energy conversion efficiency is achieved, owing to the increas in the charge transport through the photoanode. The photovoltaic performance of the present DSSC configuration is also compared with that of a cell sensitized by using standard N719 dye.

  8. Ultra-high sensitive PAH analysis of certified reference materials and environmental samples by GC-APLI-MS.

    PubMed

    Große Brinkhaus, Sigrid; Thiäner, Jan B; Achten, Christine

    2017-04-01

    Due to several polycyclic aromatic hydrocarbons (PAHs) being highly carcinogenic and at the same time occurring at very low environmental concentrations up to the microgram per kilogram range, highly sensitive chemical analysis in various matrices is needed. Here, for the first time, a method using gas chromatography (GC) and atmospheric pressure laser ionization-mass spectrometry (APLI-MS), which is much more sensitive compared to common GC-MS, proved to produce reliable (certified reference materials) and comparable (GC-MS) results. PAHs and selected isomers of alkyl-PAHs were targeted, whereby 53 analytes could be quantified individually; for one pair, the sum had to be calculated. In combination with the selective and sensitive (1+1)-REMPI process of the APLI, limits of detection (LODs) between 5 and 50 fg/μL could be obtained. To prove the reliability of this method, four certified reference materials (SRM1649b urban dust, SRM 1941b organics in marine sediment, BCR 535 fresh water harbor sediment, and ERM CC013a contaminated soil from a former gas plant site) were analyzed. The results were in good accordance with the certified values. In addition, analytical results of three different environmental matrices (bituminous coal, suspended particulate matter from river and pine needles) were compared to values obtained with well-established GC-EI-MS. The results show that this method presents an excellent tool ready-to-use for the analysis of environmental samples with very low PAH content or very low sample amount.

  9. 11% efficiency solid-state dye-sensitized solar cells with copper(II/I) hole transport materials

    PubMed Central

    Cao, Yiming; Saygili, Yasemin; Ummadisingu, Amita; Teuscher, Joël; Luo, Jingshan; Pellet, Norman; Giordano, Fabrizio; Zakeeruddin, Shaik Mohammed; Moser, Jacques -E.; Freitag, Marina; Hagfeldt, Anders; Grätzel, Michael

    2017-01-01

    Solid-state dye-sensitized solar cells currently suffer from issues such as inadequate nanopore filling, low conductivity and crystallization of hole-transport materials infiltrated in the mesoscopic TiO2 scaffolds, leading to low performances. Here we report a record 11% stable solid-state dye-sensitized solar cell under standard air mass 1.5 global using a hole-transport material composed of a blend of [Cu (4,4′,6,6′-tetramethyl-2,2′-bipyridine)2](bis(trifluoromethylsulfonyl)imide)2 and [Cu (4,4′,6,6′-tetramethyl-2,2′-bipyridine)2](bis(trifluoromethylsulfonyl)imide). The amorphous Cu(II/I) conductors that conduct holes by rapid hopping infiltrated in a 6.5 μm-thick mesoscopic TiO2 scaffold are crucial for achieving such high efficiency. Using time-resolved laser photolysis, we determine the time constants for electron injection from the photoexcited sensitizers Y123 into the TiO2 and regeneration of the Y123 by Cu(I) to be 25 ps and 3.2 μs, respectively. Our work will foster the development of low-cost solid-state photovoltaic based on transition metal complexes as hole conductors. PMID:28598436

  10. 11% efficiency solid-state dye-sensitized solar cells with copper(II/I) hole transport materials

    NASA Astrophysics Data System (ADS)

    Cao, Yiming; Saygili, Yasemin; Ummadisingu, Amita; Teuscher, Joël; Luo, Jingshan; Pellet, Norman; Giordano, Fabrizio; Zakeeruddin, Shaik Mohammed; Moser, Jacques-E.; Freitag, Marina; Hagfeldt, Anders; Grätzel, Michael

    2017-06-01

    Solid-state dye-sensitized solar cells currently suffer from issues such as inadequate nanopore filling, low conductivity and crystallization of hole-transport materials infiltrated in the mesoscopic TiO2 scaffolds, leading to low performances. Here we report a record 11% stable solid-state dye-sensitized solar cell under standard air mass 1.5 global using a hole-transport material composed of a blend of [Cu (4,4',6,6'-tetramethyl-2,2'-bipyridine)2](bis(trifluoromethylsulfonyl)imide)2 and [Cu (4,4',6,6'-tetramethyl-2,2'-bipyridine)2](bis(trifluoromethylsulfonyl)imide). The amorphous Cu(II/I) conductors that conduct holes by rapid hopping infiltrated in a 6.5 μm-thick mesoscopic TiO2 scaffold are crucial for achieving such high efficiency. Using time-resolved laser photolysis, we determine the time constants for electron injection from the photoexcited sensitizers Y123 into the TiO2 and regeneration of the Y123 by Cu(I) to be 25 ps and 3.2 μs, respectively. Our work will foster the development of low-cost solid-state photovoltaic based on transition metal complexes as hole conductors.

  11. 11% efficiency solid-state dye-sensitized solar cells with copper(II/I) hole transport materials.

    PubMed

    Cao, Yiming; Saygili, Yasemin; Ummadisingu, Amita; Teuscher, Joël; Luo, Jingshan; Pellet, Norman; Giordano, Fabrizio; Zakeeruddin, Shaik Mohammed; Moser, Jacques-E; Freitag, Marina; Hagfeldt, Anders; Grätzel, Michael

    2017-06-09

    Solid-state dye-sensitized solar cells currently suffer from issues such as inadequate nanopore filling, low conductivity and crystallization of hole-transport materials infiltrated in the mesoscopic TiO2 scaffolds, leading to low performances. Here we report a record 11% stable solid-state dye-sensitized solar cell under standard air mass 1.5 global using a hole-transport material composed of a blend of [Cu (4,4',6,6'-tetramethyl-2,2'-bipyridine)2](bis(trifluoromethylsulfonyl)imide)2 and [Cu (4,4',6,6'-tetramethyl-2,2'-bipyridine)2](bis(trifluoromethylsulfonyl)imide). The amorphous Cu(II/I) conductors that conduct holes by rapid hopping infiltrated in a 6.5 μm-thick mesoscopic TiO2 scaffold are crucial for achieving such high efficiency. Using time-resolved laser photolysis, we determine the time constants for electron injection from the photoexcited sensitizers Y123 into the TiO2 and regeneration of the Y123 by Cu(I) to be 25 ps and 3.2 μs, respectively. Our work will foster the development of low-cost solid-state photovoltaic based on transition metal complexes as hole conductors.

  12. Molecular and Material Approaches to Overcome Kinetic and Energetic Constraints in Dye-Sensitized Solar Cells

    SciTech Connect

    Hamann, Thomas

    2016-08-14

    Dye-sensitized solar cells (DSSCs) have attracted a lot of interest as they proffer the possibility of extremely inexpensive and efficient solar energy conversion. The excellent performance of the most efficient DSSCs relies on two main features: 1) a high surface area nanoparticle semiconductor photoanode to allow for excellent light absorption with moderate extinction molecular dyes and 2) slow recombination rates from the photoanode to I3- allowing good charge collection. The I3-/I- couple, however, has some disadvantages, notably the redox potential limits the maximum open-circuit voltage, and the dye regeneration requires a large driving force which constrains the light harvesting ability. Thus, the design features that allow DSSCs to perform as well as they do also prevent further significant improvements in performance. As a consequence, the most efficient device configuration, and the maximum efficiency, has remained essentially unchanged over the last 16 years. Significant gains in performance are possible; however it will likely require a substantial paradigm shift. The general goal of this project is to understand the fundamental role of dye-sensitized solar cell, DSSC, components (sensitizer, redox shuttle, and photoanode) involved in key processes in order to overcome the kinetic and energetic constraints of current generation DSSCs. For example, the key to achieving high energy conversion efficiency DSSCs is the realization of a redox shuttle which fulfills the dual requirements of 1) efficient dye regeneration with a minimal driving force and 2) efficient charge collection. In current generation DSSCs, however, only one or the other of these requirements is met. We are currently primarily interested in understanding the physical underpinnings of the regeneration and recombination reactions. Our approach is to systematically vary the components involved in reactions and interrogate them with a

  13. The innate oxygen dependant immune pathway as a sensitive parameter to predict the performance of biological graft materials.

    PubMed

    Bryan, Nicholas; Ashwin, Helen; Smart, Neil; Bayon, Yves; Scarborough, Nelson; Hunt, John A

    2012-09-01

    Clinical performance of a biomaterial is decided early after implantation as leukocytes interrogate the graft throughout acute inflammation. High degrees of leukocyte activation lead to poor material/patient compliance, accelerated degeneration and graft rejection. A number reactive oxygen species (ROS) are released by leukocytes throughout their interaction with a material, which can be used as a sensitive measure of leukocyte activation. The aim of this study was to compare leukocyte activation by commercially available biologic surgical materials and define the extent manufacturing variables influence down-stream ROS response. Chemiluminescence assays were performed using modifications to a commercially available kit (Knight Scientific, UK). Whole blood was obtained from 4 healthy human adults at 7 day intervals for 4 weeks, combined with Adjuvant K, Pholasin (a highly sensitive ROS excitable photoprotein) and biomaterial, and incubated for 60 min with continuous chemiluminescent measurements. Leukocyte ROS inducers fMLP and PMA were added as controls. Xeno- and allogeneic dermal and small intestinal submucosal (SIS) derived biomaterials were produced commercially (Surgisis Biodesign™, Alloderm(®), Strattice(®)Firm & Pliable & Permacol™) or fabricated in house to induce variations in decellularisation and cross-linking. Statistics were performed using Waller-Duncan post hoc ranking. Materials demonstrated significant differences in leukocyte activation as a function of decellularisation reagent and tissue origin. The data demonstrated SIS was significantly more pro-inflammatory than dermis. Additionally it was deduced that SDS during decellularisation induced pro-inflammatory changes to dermal materials. Furthermore, it was possible to conclude inter-patient variation in leukocyte response. The in vitro findings were validated in vivo which confirmed the chemiluminescence observations, highlighting the potential for translation of this technique as a

  14. Near-infrared laser ablation of poly tetrafluoroethylene (Teflon) sensitized by nanoenergetic materials

    SciTech Connect

    Yang Yanqiang; Wang Shufeng; Sun Zhaoyong; Dlott, Dana D.

    2004-08-30

    Laser ablation of Teflon doped with size-selected (30-250 nm) Al nanoparticles is studied. Unlike pure Teflon, which requires a vacuum-ultraviolet or femtosecond excimer laser for ablation, this sensitized Teflon can be ablated with a near-infrared laser. Using 100 ps duration pulses, near-infrared ablation thresholds are lower by about a factor of 10 from excimer ablation of pure Teflon. A mechanism is discussed that involves Teflon decomposition by spherical shock fronts originating at each irradiated nanoparticle. Studies of the distance dependence of this process as a function of particle diameter and oxide layer thickness suggest ways of optimizing the ablation process.

  15. QSPR modeling of detonation parameters and sensitivity of some energetic materials: DFT vs. PM3 calculations.

    PubMed

    Zhang, Jianying; Chen, Gangling; Gong, Xuedong

    2017-06-01

    The quantitative structure-property relationship (QSPR) methodology was applied to describe and seek the relationship between the structures and energetic properties (and sensitivity) for some common energy compounds. An extended series of structural and energetic descriptors was obtained with density functional theory (DFT) B3LYP and semi-empirical PM3 approaches. Results indicate that QSPR model constructed using quantum descriptors can be applied to verify the confidence of calculation results compared with experimental data. It can be extended to predict the properties of similar compounds.

  16. MgO:Li,Ce,Sm as a high-sensitivity material for Optically Stimulated Luminescence dosimetry

    PubMed Central

    Oliveira, Luiz C.; Yukihara, Eduardo G.; Baffa, Oswaldo

    2016-01-01

    The goal of this work was to investigate the relevant dosimetric and luminescent properties of MgO:Li3%,Ce0.03%,Sm0.03%, a newly-developed, high sensitivity Optically Stimulated Luminescence (OSL) material of low effective atomic number (Zeff = 10.8) and potential interest for medical and personal dosimetry. We characterized the thermoluminescence (TL), OSL, radioluminescence (RL), and OSL emission spectrum of this new material and carried out a preliminary investigation on the OSL signal stability. MgO:Li,Ce,Sm has a main TL peak at ~180 °C (at a heating rate of 5 °C/s) associated with Ce3+ and Sm3+ emission. The results indicate that the infrared (870 nm) stimulated OSL from MgO:Li,Ce,Sm has suitable properties for dosimetry, including high sensitivity to ionizing radiation (20 times that of Al2O3:C, under the measurement conditions) and wide dynamic range (7 μGy–30 Gy). The OSL associated with Ce3+ emission is correlated with a dominant, practically isolated peak at 180 °C. Fading of ~15% was observed in the first hour, probably due to shallow traps, followed by subsequent fading of 6–7% over the next 35 days. These properties, together with the characteristically fast luminescence from Ce3+, make this material also a strong candidate for 2D OSL dose mapping. PMID:27076349

  17. Local unitary equivalence of quantum states and simultaneous orthogonal equivalence

    NASA Astrophysics Data System (ADS)

    Jing, Naihuan; Yang, Min; Zhao, Hui

    2016-06-01

    The correspondence between local unitary equivalence of bipartite quantum states and simultaneous orthogonal equivalence is thoroughly investigated and strengthened. It is proved that local unitary equivalence can be studied through simultaneous similarity under projective orthogonal transformations, and four parametrization independent algorithms are proposed to judge when two density matrices on ℂd1 ⊗ ℂd2 are locally unitary equivalent in connection with trace identities, Kronecker pencils, Albert determinants and Smith normal forms.

  18. Fission Product Gamma-Ray Line Pairs Sensitive to Fissile Material and Neutron Energy

    SciTech Connect

    Marrs, R E; Norman, E B; Burke, J T; Macri, R A; Shugart, H A; Browne, E; Smith, A R

    2007-11-15

    The beta-delayed gamma-ray spectra from the fission of {sup 235}U, {sup 238}U, and {sup 239}Pu by thermal and near-14-MeV neutrons have been measured for delay times ranging from 1 minute to 14 hours. Spectra at all delay times contain sets of prominent gamma-ray lines with intensity ratios that identify the fissile material and distinguish between fission induced by low-energy or high-energy neutrons.

  19. Temperature- and pH-sensitive wearable materials for monitoring foot ulcers

    PubMed Central

    Salvo, Pietro; Calisi, Nicola; Melai, Bernardo; Dini, Valentina; Paoletti, Clara; Lomonaco, Tommaso; Pucci, Andrea; Di Francesco, Fabio; Piaggesi, Alberto; Romanelli, Marco

    2017-01-01

    Foot ulcers account for 15% of comorbidities associated with diabetes. Presently, no device allows the status of foot ulcers to be continuously monitored when patients are not hospitalized. In this study, we describe a temperature and a pH sensor capable of monitoring diabetic foot and venous leg ulcers developed in the frame of the seventh framework program European Union project SWAN-iCare (smart wearable and autonomous negative pressure device for wound monitoring and therapy). Temperature is measured by exploiting the variations in the electrical resistance of a nanocomposite consisting of multiwalled carbon nanotubes and poly(styrene-b-(ethylene-co-butylene)-b-styrene). The pH sensor used a graphene oxide (GO) layer that changes its electrical potential when pH changes. The temperature sensor has a sensitivity of ~85 Ω/°C in the range 25°C–50°C and a high repeatability (maximum standard deviation of 0.1% over seven repeated measurements). For a GO concentration of 4 mg/mL, the pH sensor has a sensitivity of ~42 mV/pH and high linearity (R2=0.99). PMID:28203074

  20. Ultra-Weak Fiber Bragg Grating Sensing Network Coated with Sensitive Material for Multi-Parameter Measurements

    PubMed Central

    Bai, Wei; Yang, Minghong; Hu, Chenyuan; Dai, Jixiang; Zhong, Xuexiang; Huang, Shuai; Wang, Gaopeng

    2017-01-01

    A multi-parameter measurement system based on ultra-weak fiber Bragg grating (UFBG) array with sensitive material was proposed and experimentally demonstrated. The UFBG array interrogation principle is time division multiplex technology with two semiconductor optical amplifiers as timing units. Experimental results showed that the performance of the proposed UFBG system is almost equal to that of traditional FBG, while the UFBG array system has obvious superiority with potential multiplexing ability for multi-point and multi-parameter measurement. The system experimented on a 144 UFBG array with the reflectivity of UFBG ~0.04% for the four target parameters: hydrogen, humidity, temperature and salinity. Moreover, a uniform solution was customized to divide the cross-sensitivity between temperature and other target parameters. It is expected that this scheme will be capable of handling thousands of multi-parameter sensors in a single fiber. PMID:28672872

  1. High-resolution setup for measuring wavelength sensitivity of photoyellowing of translucent materials

    SciTech Connect

    Vaskuri, Anna Kärhä, Petri; Heikkilä, Anu

    2015-10-15

    Polystyrene and many other materials turn yellow when exposed to ultraviolet (UV) radiation. All photodegradation mechanisms including photoyellowing are functions of the exposure wavelength, which can be described with an action spectrum. In this work, a new high-resolution transmittance measurement setup based on lasers has been developed for measuring color changes, such as the photoyellowing of translucent materials aged with a spectrograph. The measurement setup includes 14 power-stabilized laser lines between 325 nm and 933 nm wavelengths, of which one at a time is directed on to the aged sample. The power transmitted through the sample is measured with a silicon detector utilizing an integrating sphere. The sample is mounted on a high-resolution XY translation stage. Measurement at various locations aged with different wavelengths of exposure radiation gives the transmittance data required for acquiring the action spectrum. The combination of a UV spectrograph and the new high-resolution transmittance measurement setup enables a novel method for studying the UV-induced ageing of translucent materials with a spectral resolution of 3–8 nm, limited by the adjustable spectral bandwidth range of the spectrograph. These achievements form a significant improvement over earlier methods.

  2. Highly Sensitive Gamma-Spectrometers of Gerda for Material Screening: Part 2

    SciTech Connect

    Budjas, Dusan; Hampel, W.; Heisel, M.; Heusser, G.; Keillor, Marty; Laubenstein, M.; Maneschg, W.; Rugel, G.; Schonert, S.; Simgen, H.; Strecker, H.

    2007-04-21

    The previous article about material screening for Gerda points out the importance of strict material screening and selection for radioimpurities as a key to meet the aspired background levels of the Gerda experiment. This is directly done using low-level gammaspectroscopy. In order to provide sufficient selective power in the mBq/kg range and below, the employed gamma-spectrometers themselves have to meet strict material requirements, and make use of an elaborate shielding system. This article gives an account of the setup of two such spectrometers. Corrado is located in a depth of 15 m w.e. at the MPI-K in Heidelberg (Germany), Gempi III is situated at the Gran-Sasso underground laboratory at 3500 m w.e. (Italy). The latter one aims at detecting sample activities of the order ~10 μBq/kg, which is the current state-of-the-art level. The applied techniques to meet the respective needs are discussed and demonstrated by experimental results.

  3. Tailoring Oxygen Sensitivity with Halide Substitution in Difluoroboron Dibenzoylmethane Polylactide Materials

    PubMed Central

    DeRosa, Christopher A.; Kerr, Caroline; Fan, Ziyi; Kolpaczynska, Milena; Mathew, Alexander S.; Evans, Ruffin E.; Zhang, Guoqing; Fraser, Cassandra L.

    2015-01-01

    The dual-emissive properties of solid-state difluoroboron β-diketonate-poly(lactic acid) (BF2bdkPLA) materials have been utilized for biological oxygen sensing. In this work, BF2dbm(X)PLA materials were synthesized, where X = H, F, Cl, Br, and I. The effects of changing the halide substituent and PLA polymer chain length on the optical properties in dilute CH2Cl2 solutions and solid-state polymer films were studied. These luminescent materials show fluorescence, phosphorescence, and lifetime tunability on the basis of molecular weight, as well as lifetime modulation via the halide substituent. Short BF2dbm(Br)PLA (6.0 kDa) and both short and long BF2dbm(I)PLA polymers (6.0 or 20.3 kDa) have fluorescence and intense phosphorescence ideal for ratiometric oxygen sensing. The lighter halide-dye polymers with hydrogen, fluorine, and chlorine substitution have longer phosphorescence lifetimes and can be utilized as ultrasensitive oxygen sensors. Photostability was also analyzed for the polymer films. PMID:26480236

  4. High-resolution setup for measuring wavelength sensitivity of photoyellowing of translucent materials.

    PubMed

    Vaskuri, Anna; Kärhä, Petri; Heikkilä, Anu; Ikonen, Erkki

    2015-10-01

    Polystyrene and many other materials turn yellow when exposed to ultraviolet (UV) radiation. All photodegradation mechanisms including photoyellowing are functions of the exposure wavelength, which can be described with an action spectrum. In this work, a new high-resolution transmittance measurement setup based on lasers has been developed for measuring color changes, such as the photoyellowing of translucent materials aged with a spectrograph. The measurement setup includes 14 power-stabilized laser lines between 325 nm and 933 nm wavelengths, of which one at a time is directed on to the aged sample. The power transmitted through the sample is measured with a silicon detector utilizing an integrating sphere. The sample is mounted on a high-resolution XY translation stage. Measurement at various locations aged with different wavelengths of exposure radiation gives the transmittance data required for acquiring the action spectrum. The combination of a UV spectrograph and the new high-resolution transmittance measurement setup enables a novel method for studying the UV-induced ageing of translucent materials with a spectral resolution of 3-8 nm, limited by the adjustable spectral bandwidth range of the spectrograph. These achievements form a significant improvement over earlier methods.

  5. High-resolution setup for measuring wavelength sensitivity of photoyellowing of translucent materials

    NASA Astrophysics Data System (ADS)

    Vaskuri, Anna; Kärhä, Petri; Heikkilä, Anu; Ikonen, Erkki

    2015-10-01

    Polystyrene and many other materials turn yellow when exposed to ultraviolet (UV) radiation. All photodegradation mechanisms including photoyellowing are functions of the exposure wavelength, which can be described with an action spectrum. In this work, a new high-resolution transmittance measurement setup based on lasers has been developed for measuring color changes, such as the photoyellowing of translucent materials aged with a spectrograph. The measurement setup includes 14 power-stabilized laser lines between 325 nm and 933 nm wavelengths, of which one at a time is directed on to the aged sample. The power transmitted through the sample is measured with a silicon detector utilizing an integrating sphere. The sample is mounted on a high-resolution XY translation stage. Measurement at various locations aged with different wavelengths of exposure radiation gives the transmittance data required for acquiring the action spectrum. The combination of a UV spectrograph and the new high-resolution transmittance measurement setup enables a novel method for studying the UV-induced ageing of translucent materials with a spectral resolution of 3-8 nm, limited by the adjustable spectral bandwidth range of the spectrograph. These achievements form a significant improvement over earlier methods.

  6. Temperature sensitivity of CO2, CH4, CO, and H2 emissions during photodegradation of plant material

    NASA Astrophysics Data System (ADS)

    Lee, H.; Throop, H. L.; Rahn, T.

    2010-12-01

    Recent studies suggest that photochemical breakdown (hereafter ‘photodegradation’) of plant material by ultraviolet (UV) radiation may circumvent biotic decomposition and contribute up to 33% of decomposition in arid and semiarid ecosystems. Current knowledge of UV effects on the breakdown of plant-derived carbon compounds such as cellulose and lignin is limited. Several other observations showed that photodegradation of plant material not only produces CO2, but also produces CO and CH4. These observations also suggested that the gas production may be sensitive to temperature. We established a laboratory experiment to test the temperature sensitivity of greenhouse gases (CO2 and CH4) and indirect greenhouse gases (CO and H2) during photodegradation of plant material. The photochemical reaction was induced using a 300 W Xenon lamp solar simulator in a closed quartz chamber connected to a high resolution Wavelength-Scanned Cavity Ringdown Spectroscopy CO2-CH4 analyzer and a reduced compound photometer CO and H2 gas chromatograph. We attached a water bath connected to a chiller/heater below the chamber to control chamber temperatures at 15, 25, 35, 45, and 55°C. We compared emission rates from two artificial materials that were high in lignin and cellulose (basswood sheet and high cellulose content filter paper, respectively) and leaves of two plant species (honey mesquite and little bluestem grass). The rate of CO2 and CO emissions from photodegradation of plant material ranged from 3-70 μg CO2-C m-2 hr-1 and 2-30 μg CO-C m-2 hr-1 and were positively correlated to temperature for all materials (magnitude of fluxes: basswood > mesquite = grass > filter paper). In contrast, the rate of CH4 and H2 ranged from 0-0.4 μg CH4-C m-2 hr-1 and 0-0.4 μg H2 m-2 hr-1, but the temperature responses varied among materials. For instance, the rate of CH4 and H2 emissions were positively correlated with temperature during photodegradation of basswood, but they were negatively

  7. Strain-rate sensitivity of foam materials: A numerical study using 3D image-based finite element model

    NASA Astrophysics Data System (ADS)

    Sun, Yongle; Li, Q. M.; Withers, P. J.

    2015-09-01

    Realistic simulations are increasingly demanded to clarify the dynamic behaviour of foam materials, because, on one hand, the significant variability (e.g. 20% scatter band) of foam properties and the lack of reliable dynamic test methods for foams bring particular difficulty to accurately evaluate the strain-rate sensitivity in experiments; while on the other hand numerical models based on idealised cell structures (e.g. Kelvin and Voronoi) may not be sufficiently representative to capture the actual structural effect. To overcome these limitations, the strain-rate sensitivity of the compressive and tensile properties of closed-cell aluminium Alporas foam is investigated in this study by means of meso-scale realistic finite element (FE) simulations. The FE modelling method based on X-ray computed tomography (CT) image is introduced first, as well as its applications to foam materials. Then the compression and tension of Alporas foam at a wide variety of applied nominal strain-rates are simulated using FE model constructed from the actual cell geometry obtained from the CT image. The stain-rate sensitivity of compressive strength (collapse stress) and tensile strength (0.2% offset yield point) are evaluated when considering different cell-wall material properties. The numerical results show that the rate dependence of cell-wall material is the main cause of the strain-rate hardening of the compressive and tensile strengths at low and intermediate strain-rates. When the strain-rate is sufficiently high, shock compression is initiated, which significantly enhances the stress at the loading end and has complicated effect on the stress at the supporting end. The plastic tensile wave effect is evident at high strain-rates, but shock tension cannot develop in Alporas foam due to the softening associated with single fracture process zone occurring in tensile response. In all cases the micro inertia of individual cell walls subjected to localised deformation is found to

  8. Establishing Substantial Equivalence: Proteomics

    NASA Astrophysics Data System (ADS)

    Lovegrove, Alison; Salt, Louise; Shewry, Peter R.

    Wheat is a major crop in world agriculture and is consumed after processing into a range of food products. It is therefore of great importance to determine the consequences (intended and unintended) of transgenesis in wheat and whether genetically modified lines are substantially equivalent to those produced by conventional plant breeding. Proteomic analysis is one of several approaches which can be used to address these questions. Two-dimensional PAGE (2D PAGE) remains the most widely available method for proteomic analysis, but is notoriously difficult to reproduce between laboratories. We therefore describe methods which have been developed as standard operating procedures in our laboratory to ensure the reproducibility of proteomic analyses of wheat using 2D PAGE analysis of grain proteins.

  9. 33 CFR 155.120 - Equivalents.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Equivalents. 155.120 Section 155.120 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION OIL OR HAZARDOUS MATERIAL POLLUTION PREVENTION REGULATIONS FOR VESSELS General § 155.120...

  10. 33 CFR 155.120 - Equivalents.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Equivalents. 155.120 Section 155.120 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION OIL OR HAZARDOUS MATERIAL POLLUTION PREVENTION REGULATIONS FOR VESSELS General § 155.120...

  11. 33 CFR 155.120 - Equivalents.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Equivalents. 155.120 Section 155.120 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION OIL OR HAZARDOUS MATERIAL POLLUTION PREVENTION REGULATIONS FOR VESSELS General § 155.120...

  12. 33 CFR 155.120 - Equivalents.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Equivalents. 155.120 Section 155.120 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION OIL OR HAZARDOUS MATERIAL POLLUTION PREVENTION REGULATIONS FOR VESSELS General § 155.120...

  13. Equivalent weight of humic acid from peat

    USGS Publications Warehouse

    Pommer, A.M.; Breger, I.A.

    1960-01-01

    By means of discontinuous titration, the equivalent weight of humic acid isolated from a peat was found to increase from 144 to 183 between the third and fifty-second day after the humic acid was dissolved. Infra-red studies showed that the material had probably condensed with loss of carbonyl groups. ?? 1960.

  14. Angular Momentum Eigenstates for Equivalent Electrons.

    ERIC Educational Resources Information Center

    Tuttle, E. R.; Calvert, J. B.

    1981-01-01

    Simple and efficient methods for adding angular momenta and for finding angular momentum eigenstates for systems of equivalent electrons are developed. Several different common representations are used in specific examples. The material is suitable for a graduate course in quantum mechanics. (SK)

  15. Angular Momentum Eigenstates for Equivalent Electrons.

    ERIC Educational Resources Information Center

    Tuttle, E. R.; Calvert, J. B.

    1981-01-01

    Simple and efficient methods for adding angular momenta and for finding angular momentum eigenstates for systems of equivalent electrons are developed. Several different common representations are used in specific examples. The material is suitable for a graduate course in quantum mechanics. (SK)

  16. Nitramines with varying sensitivities: functionalized dipyrazolyl-N-nitromethanamines as energetic materials.

    PubMed

    Zhang, Jiaheng; He, Chunlin; Parrish, Damon A; Shreeve, Jean'ne M

    2013-07-01

    1,3-Dichloro-2-nitro-2-azapropane is an excellent precursor to dense energetic functionalized dipyrazolyl-N-nitromethanamines. This new family of energetic compounds was fully characterized by using (1)H, (13)C, and (15)N NMR and IR spectroscopy, differential scanning calorimetry, elemental analysis, and impact sensitivity tests. Additionally, single-crystal X-ray structuring was done for 3 and 5·CH3CN, which gave insight into structural characteristics. The experimentally determined densities of 2-9 fall between 1.69 and 1.90 g cm(-3). Heats of formation and detonation properties were calculated by using Gaussian 03 and EXPLO5 programs, respectively. The influence of different energetic moieties on the structural and energetic properties was established theoretically. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Carbon nanohorns as integrative materials for efficient dye-sensitized solar cells.

    PubMed

    Costa, Rubén D; Feihl, Sebastian; Kahnt, Axel; Gambhir, Sanjeev; Officer, David L; Wallace, Gordon G; Lucio, María Isabel; Herrero, María Antonia; Vázquez, Ester; Syrgiannis, Zois; Prato, Maurizio; Guldi, Dirk M

    2013-12-03

    Different nanocarbons, that is, single-wall carbon nanotubes, graphene, single-wall carbon nanohorns (SWCNHs), and their respective oxidized analogs have been used to fabricate novel doped TiO2 electrodes for DSSCs. Our results indicate that all of the nanocarbons significantly enhance the device characteristics when compared to standard TiO2 electrodes. Overall, our most outstanding finding is that SWCNH derivatives are also a plausible material for developing highly-efficient DSSCs. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Protection of temperature sensitive biomedical products using molecular alloys as phase change material.

    PubMed

    Mondieig, Denise; Rajabalee, Fazil; Laprie, Alain; Oonk, Harry A J; Calvet, Thereza; Cuevas-Diarte, Miguel Angel

    2003-04-01

    In this paper we present an example of the application of molecular alloys for thermal protection of biomedical products during transport or storage. Particularly, thermal protection of blood elements have been considered at different temperatures. All steps from basic research to marketing have been addressed. The high latent heat of fusion of the components allows us to propose molecular alloys as materials for thermal energy storage and also for thermal protection over a large range of temperatures, which can be used in many industrial sectors.

  19. Efficient Natural Dye-Sensitized Solar Cells Based on Spin-Coated TiO2 Anode Materials

    NASA Astrophysics Data System (ADS)

    Yu, Xiao-Hong; Sun, Zhao-Zong; Lian, Jie; Li, Yi-Tan; Chen, Yan-Xue; Gao, Shang; Wang, Xiao; Wang, Ying-Shun; Zhao, Ming-Lin

    2013-11-01

    TiO2 anode materials are prepared on ITO glass by spin-coated method. Dye-sensitized solar cells are assembled with these anodes and natural dyes extracted from radix ophiopogonis by different solvents. The formation and characterization of anode materials are confirmed by field-emission scanning electron microscopy, x-ray diffraction, UV-visible absorption spectroscopy. Photovoltaic testing results show that energy conversion efficiency could reach 1.67% with fill factor of 0.51, open-circuit voltage of 457 mV, and short-circuit photocurrent density of 7.2 mA/cm2. The short-circuit photocurrent density can reach 7.6 mA/cm2 with efficiency of 1.33.

  20. The PRIDE (Partnership to Improve Diabetes Education) Toolkit: Development and Evaluation of Novel Literacy and Culturally Sensitive Diabetes Education Materials.

    PubMed

    Wolff, Kathleen; Chambers, Laura; Bumol, Stefan; White, Richard O; Gregory, Becky Pratt; Davis, Dianne; Rothman, Russell L

    2016-02-01

    Patients with low literacy, low numeracy, and/or linguistic needs can experience challenges understanding diabetes information and applying concepts to their self-management. The authors designed a toolkit of education materials that are sensitive to patients' literacy and numeracy levels, language preferences, and cultural norms and that encourage shared goal setting to improve diabetes self-management and health outcomes. The Partnership to Improve Diabetes Education (PRIDE) toolkit was developed to facilitate diabetes self-management education and support. The PRIDE toolkit includes a comprehensive set of 30 interactive education modules in English and Spanish to support diabetes self-management activities. The toolkit builds upon the authors' previously validated Diabetes Literacy and Numeracy Education Toolkit (DLNET) by adding a focus on shared goal setting, addressing the needs of Spanish-speaking patients, and including a broader range of diabetes management topics. Each PRIDE module was evaluated using the Suitability Assessment of Materials (SAM) instrument to determine the material's cultural appropriateness and its sensitivity to the needs of patients with low literacy and low numeracy. Reading grade level was also assessed using the Automated Readability Index (ARI), Coleman-Liau, Flesch-Kincaid, Fry, and SMOG formulas. The average reading grade level of the materials was 5.3 (SD 1.0), with a mean SAM of 91.2 (SD 5.4). All of the 30 modules received a "superior" score (SAM >70%) when evaluated by 2 independent raters. The PRIDE toolkit modules can be used by all members of a multidisciplinary team to assist patients with low literacy and low numeracy in managing their diabetes. © 2015 The Author(s).

  1. Dose equivalent neutron dosimeter

    DOEpatents

    Griffith, Richard V.; Hankins, Dale E.; Tomasino, Luigi; Gomaa, Mohamed A. M.

    1983-01-01

    A neutron dosimeter is disclosed which provides a single measurements indicating the amount of potential biological damage resulting from the neutron exposure of the wearer, for a wide range of neutron energies. The dosimeter includes a detecting sheet of track etch detecting material such as a carbonate plastic, for detecting higher energy neutrons, and a radiator layer containing conversion material such as .sup.6 Li and .sup.10 B lying adjacent to the detecting sheet for converting moderate energy neutrons to alpha particles that produce tracks in the adjacent detecting sheet. The density of conversion material in the radiator layer is of an amount which is chosen so that the density of tracks produced in the detecting sheet is proportional to the biological damage done by neutrons, regardless of whether the tracks are produced as the result of moderate energy neutrons striking the radiator layer or as the result of higher energy neutrons striking the sheet of track etch material.

  2. Natural background dose and radium equivalent measurements at Ikogosi warm spring, Nigeria.

    PubMed

    Isinkaye, M O; Ajayi, I R

    2006-01-01

    The natural background dose and the radium equivalent due to the natural radioactivity levels in rocks and sediments collected around Ikogosi warm spring, Nigeria, has been determined in this study using a highly sensitive HpGe detector. The mean activity concentration of (40)K, (226)Ra and (228)Ac were measured to be 585.50 +/- 17.40 Bq kg(-1), 66.91 +/- 5.23 Bq kg(-1) and 48.91 +/- 2.10 Bq kg(-1), respectively, in rock samples while in sediment samples the activity concentrations were found to be 113.89 +/- 5.64 Bq kg(-1) for (40)K, 21.47 +/- 5.14 Bq kg(-1) for (226)Ra and 14.20 +/- 1.07 Bq kg(-1) for (228)Ac. This mean values give rise to average absorbed dose rate of 85.87 nGy h(-1) at a distance of 1.0 m above the ground level and a mean human effective dose equivalent of 0.53 man Sv y(-1) for rock samples. A radium equivalent of 50.55 Bq kg(-1) was measured for the sediment samples. The radium equivalent value is far less than the 370 Bq kg(-1) limit for materials that can be used as building materials while the human effective dose equivalent falls below the world average background dose of 2.4 man Sv y(-1).

  3. An additional S-shaped structure for sensitivity improvement of coaxial probe for permittivity determination of low loss materials

    NASA Astrophysics Data System (ADS)

    Jiao, Xingmin; Jin, Wei; Yang, Xiaoqing

    2015-05-01

    Permittivity measurement of materials is important in microwave chemistry, microwave material processing and microwave heating. The open-ended coaxial line method is one of the most popular and effective means for permittivity measurement. However, the conventional coaxial probe has difficulty in distinguishing small permittivity variations for low loss media. In this paper an additional S-shaped structure is proposed for sensitivity improvement of a coaxial probe for permittivity determination of low loss materials at 2.45 GHz. The small permittivity variation can be distinguished due to field enhancement generated by the additional S-shaped structure. We studied the variation of reflection coefficient amplitude for three kinds of samples with different moisture content, within the probe at different insertion depths. We find that the conventional coaxial probe cannot distinguish small permittivity variations until the moisture content of materials reaches 3%. Meanwhile, the probe with the S-shaped structure can detect such small permittivity variations when the moisture content of samples changes by only 1%. The experimental results demonstrate that the new probe proposed in this paper is reliable and feasible.

  4. Highly selective and sensitive trimethylamine gas sensor based on cobalt imidazolate framework material.

    PubMed

    Chen, Er-Xia; Fu, Hong-Ru; Lin, Rui; Tan, Yan-Xi; Zhang, Jian

    2014-12-24

    A cobalt imidazolate (im) framework material [Co(im)2]n was employed to use as a trimethylamine (TMA) gas sensor and the [Co(im)2]n sensor can be easily fabricated by using Ag-Pd interdigitated electrodes. Gas sensing measurement indicated that the [Co(im)2]n sensor shows excellent selectivity, high gas response and a low detection limit level of 2 ppm to TMA at 75 °C. The good selectivity and high response to TMA of the sensor based on [Co(im)2]n may be attributed to the weak interaction between the TMA molecules and the [Co(im)2]n framework. That may provide an ideal candidate for detecting freshness of fish and seafood.

  5. The gas sensitive material Cr (2-x) Ti (x) O3

    NASA Astrophysics Data System (ADS)

    Niemeyer, Dirk

    Chromium titanium oxide (CTO) is a recently discovered gas sensor material that is capable of detecting small concentrations of toxic or flammable gases in air with stability of performance over the short and long-term and minor influences of variations of humidity. CTO is the first new material to be successfully commercialised in large-volume manufacture for sensing of hydrocarbons, VOCs, hydrogen and carbon monoxide at low (ppm) concentrations in air since the introduction of SnO2 for this purpose in the 1960s. The main focus of this thesis lies in the systematic investigation of this material in order to develop a detailed theoretical understanding of the gas response mechanism. CTO was prepared by solid-state reaction of Cr2O3 and TiO2 in air at 1000C. It crystallises in a solid solution with the general formula Cr2-xTixO3. The phase limit is at x ~ 0.3-0.4. Above the phase limit a 2-phase mixture with CrTiO3 is found. Substitution of Ti strongly decreases the electrical conductivity of the porous bodies studied. This effect, and the surface segregation of Ti, controls the gas sensor behaviour. Atomistic simulations have been performed on the (0001) and (1012) face to assess defect models for pure- and titanium doped Cr2O3. In the absence of titanium, one stable defect is a CrVI - Vcr" pair, which segregates to the (0001) surface and contributes to the relatively high p-type conductivity shown by finely porous bodies of Cr2O3 at elevated temperature; with titanium addition, a stable defect, segregated on both of the investigated surfaces, is the complex (TiIV)3Vcr". The proportion of surface CrVI is decreased. Surface studies of Cr2O3 have been performed extensively in the literature because it adsorbs oxygen and catalyses combustion of hydrocarbons. Whilst Cr2O3 shows a good combustion rate of CO to CO2 but only a small gas response, titanium doped Cr2O3 behaves the opposite way. X-ray photoelectron spectroscopy of the chromium 2p3/2 core states show a

  6. Dissolution testing of hardly soluble materials by surface sensitive techniques: clotrimazole from an insoluble matrix.

    PubMed

    Ehmann, Heike M A; Winter, Sascha; Griesser, Thomas; Keimel, Roman; Schrank, Simone; Zimmer, Andreas; Werzer, Oliver

    2014-10-01

    The low aqueous solubility of many drugs impedes detailed investigation as the detection limit of standard testing routines is limited. This is further complicated within application relevant thin films typical used in patches or stripes for buccal or topical routes. In this work a model system is developed based on spin - casting technique allowing defined clotrimazole and clotrimazole - polystyrene composite films preparation at a solid surface. Various highly sensitive techniques including quarz crystal microbalance (QCM), X-ray reflevtivity (XRR) and X-ray photon spectroscopy (XPS) are used to investigate the drug release over time into an aqueous media. The results reveal a steady drug release for both samples over the course of the experiments but with the release from the composite being significantly slower. In addition the dissolution rate of the clotrimazole sample initially increases up to 30 min after which a decrease is noted. XRR shows that this is a result of surface roughening together with film thickness reduction. The results for the composite show that the release in the composite film is a result of drug diffusion within the matrix and collapsing PS film thickness whereby XPS shows that the amount of clotrimazole at the surface after 800 min immersion is still high. It can be stated that the applied techniques allow following low mass drug release in detail which may also be applied to other systems like pellets or surface loaded nano-carriers providing information for processing and application relevant parameters.

  7. Evaluating the Sensitivity of Agricultural Model Performance to Different Climate Inputs: Supplemental Material

    NASA Technical Reports Server (NTRS)

    Glotter, Michael J.; Ruane, Alex C.; Moyer, Elisabeth J.; Elliott, Joshua W.

    2015-01-01

    Projections of future food production necessarily rely on models, which must themselves be validated through historical assessments comparing modeled and observed yields. Reliable historical validation requires both accurate agricultural models and accurate climate inputs. Problems with either may compromise the validation exercise. Previous studies have compared the effects of different climate inputs on agricultural projections but either incompletely or without a ground truth of observed yields that would allow distinguishing errors due to climate inputs from those intrinsic to the crop model. This study is a systematic evaluation of the reliability of a widely used crop model for simulating U.S. maize yields when driven by multiple observational data products. The parallelized Decision Support System for Agrotechnology Transfer (pDSSAT) is driven with climate inputs from multiple sources reanalysis, reanalysis that is bias corrected with observed climate, and a control dataset and compared with observed historical yields. The simulations show that model output is more accurate when driven by any observation-based precipitation product than when driven by non-bias-corrected reanalysis. The simulations also suggest, in contrast to previous studies, that biased precipitation distribution is significant for yields only in arid regions. Some issues persist for all choices of climate inputs: crop yields appear to be oversensitive to precipitation fluctuations but under sensitive to floods and heat waves. These results suggest that the most important issue for agricultural projections may be not climate inputs but structural limitations in the crop models themselves.

  8. Reciprocal space mapping of epitaxial materials using position-sensitive x-ray detection

    SciTech Connect

    Lee, S.R.; Doyle, B.L.; Drummond, T.J.; Medernach, J.W.; Schneider, R.P. Jr.

    1994-10-01

    Reciprocal space mapping can be efficiently carried out using a position-sensitive x-ray detector (PSD) coupled to a traditional double-axis diffractometer. The PSD offers parallel measurement of the total scattering angle of all diffracted x-rays during a single rocking-curve scan. As a result, a two-dimensional reciprocal space map can be made in a very short time similar to that of a one-dimensional rocking-curve scan. Fast, efficient reciprocal space mapping offers numerous routine advantages to the x-ray diffraction analyst. Some of these advantages are the explicit differentiation of lattice strain from crystal orientation effects in strain-relaxed heteroepitaxial layers; the nondestructive characterization of the size, shape and orientation of nanocrystalline domains in ordered-alloy epilayers; and the ability to measure the average size and shape of voids in porous epilayers. Here, the PSD-based diffractometer is described, and specific examples clearly illustrating the advantages of complete reciprocal space analysis are presented.

  9. A Highly Sensitive Multicommuted Flow Analysis Procedure for Photometric Determination of Molybdenum in Plant Materials without a Solvent Extraction Step.

    PubMed

    Santos, Felisberto G; Reis, Boaventura F

    2017-01-01

    A highly sensitive analytical procedure for photometric determination of molybdenum in plant materials was developed and validated. This procedure is based on the reaction of Mo(V) with thiocyanate ions (SCN(-)) in acidic medium to form a compound that can be monitored at 474 nm and was implemented employing a multicommuted flow analysis setup. Photometric detection was performed using an LED-based photometer coupled to a flow cell with a long optical path length (200 mm) to achieve high sensitivity, allowing Mo(V) determination at a level of μg L(-1) without the use of an organic solvent extraction step. After optimization of operational conditions, samples of digested plant materials were analyzed employing the proposed procedure. The accuracy was assessed by comparing the obtained results with those of a reference method, with an agreement observed at 95% confidence level. In addition, a detection limit of 9.1 μg L(-1), a linear response (r = 0.9969) over the concentration range of 50-500 μg L(-1), generation of only 3.75 mL of waste per determination, and a sampling rate of 51 determinations per hour were achieved.

  10. Reproducing Kernel Particle Method in Plasticity of Pressure-Sensitive Material with Reference to Powder Forming Process

    NASA Astrophysics Data System (ADS)

    Khoei, A. R.; Samimi, M.; Azami, A. R.

    2007-02-01

    In this paper, an application of the reproducing kernel particle method (RKPM) is presented in plasticity behavior of pressure-sensitive material. The RKPM technique is implemented in large deformation analysis of powder compaction process. The RKPM shape function and its derivatives are constructed by imposing the consistency conditions. The essential boundary conditions are enforced by the use of the penalty approach. The support of the RKPM shape function covers the same set of particles during powder compaction, hence no instability is encountered in the large deformation computation. A double-surface plasticity model is developed in numerical simulation of pressure-sensitive material. The plasticity model includes a failure surface and an elliptical cap, which closes the open space between the failure surface and hydrostatic axis. The moving cap expands in the stress space according to a specified hardening rule. The cap model is presented within the framework of large deformation RKPM analysis in order to predict the non-uniform relative density distribution during powder die pressing. Numerical computations are performed to demonstrate the applicability of the algorithm in modeling of powder forming processes and the results are compared to those obtained from finite element simulation to demonstrate the accuracy of the proposed model.

  11. A Highly Sensitive Multicommuted Flow Analysis Procedure for Photometric Determination of Molybdenum in Plant Materials without a Solvent Extraction Step

    PubMed Central

    Santos, Felisberto G.

    2017-01-01

    A highly sensitive analytical procedure for photometric determination of molybdenum in plant materials was developed and validated. This procedure is based on the reaction of Mo(V) with thiocyanate ions (SCN−) in acidic medium to form a compound that can be monitored at 474 nm and was implemented employing a multicommuted flow analysis setup. Photometric detection was performed using an LED-based photometer coupled to a flow cell with a long optical path length (200 mm) to achieve high sensitivity, allowing Mo(V) determination at a level of μg L−1 without the use of an organic solvent extraction step. After optimization of operational conditions, samples of digested plant materials were analyzed employing the proposed procedure. The accuracy was assessed by comparing the obtained results with those of a reference method, with an agreement observed at 95% confidence level. In addition, a detection limit of 9.1 μg L−1, a linear response (r = 0.9969) over the concentration range of 50–500 μg L−1, generation of only 3.75 mL of waste per determination, and a sampling rate of 51 determinations per hour were achieved. PMID:28357152

  12. An endoscopic shearography system with radial sensitivity for inner inspection of adhesion faults in composite material pipes

    NASA Astrophysics Data System (ADS)

    Benedet, M. E.; Macedo, F. J.; Fantin, A. V.; Willemann, D. P.; Silva, F. A. A.; Soares, S. D.; Albertazzi, A.

    2017-06-01

    This work presents the development of a special shearography system with radial sensitivity and explores its applicability for detecting adhesion flaws on internal surfaces of joints of composite material pipes. The system uses two conical mirrors to achieve radial sensitivity. A primary 45° conical mirror is responsible for promoting the inspection of the internal surface all way around 360°. A special Michelson-like interferometer is formed replacing one of the plane mirrors by a conical mirror. The image reflected by this conical mirror is shifted away from the image center in a radial way and a radial shear is produced on the images. The concept was developed and tested. Two tubular steel specimens internally coated with composite materials and having known artificial defects were analyzed to test the ability of the system to detect the flaws. The system presented very good results on all inspected specimens. The experimental results obtained in this work are promising and open a new front for inspections of inner surfaces of composite pipes with shearography.

  13. Nanocrystalline BaSnO₃ as an Alternative Gas Sensor Material: Surface Reactivity and High Sensitivity to SO₂.

    PubMed

    Marikutsa, Artem; Rumyantseva, Marina; Baranchikov, Alexander; Gaskov, Alexander

    2015-09-18

    Nanocrystalline perovskite-type BaSnO₃ was obtained via microwave-assisted hydrothermal route followed by annealing at variable temperature. The samples composition and microstructure were characterized. Particle size of 18-23 nm was unaffected by heat treatment at 275-700 °C. Materials DC-conduction was measured at variable temperature and oxygen concentration. Barium stannate exhibited n-type semiconductor behavior at 150-450 °C with activation energy being dependent on the materials annealing temperature. Predominant ionosorbed oxygen species types were estimated. They were shown to change from molecular to atomic species on increasing temperature. Comparative test of sensor response to various inorganic target gases was performed using nanocrystalline SnO₂-based sensors as reference ones. Despite one order of magnitude smaller surface area, BaSnO₃ displayed higher sensitivity to SO₂ in comparison with SnO₂. DRIFT spectroscopy revealed distinct interaction routes of the oxides surfaces with SO₂. Barium-promoted sulfate formation favoring target molecules oxidation was found responsible for the increased BaSnO₃ sensitivity to ppm-range concentrations of SO₂ in air.

  14. Nanocrystalline BaSnO3 as an Alternative Gas Sensor Material: Surface Reactivity and High Sensitivity to SO2

    PubMed Central

    Marikutsa, Artem; Rumyantseva, Marina; Baranchikov, Alexander; Gaskov, Alexander

    2015-01-01

    Nanocrystalline perovskite-type BaSnO3 was obtained via microwave-assisted hydrothermal route followed by annealing at variable temperature. The samples composition and microstructure were characterized. Particle size of 18–23 nm was unaffected by heat treatment at 275–700 °C. Materials DC-conduction was measured at variable temperature and oxygen concentration. Barium stannate exhibited n-type semiconductor behavior at 150–450 °C with activation energy being dependent on the materials annealing temperature. Predominant ionosorbed oxygen species types were estimated. They were shown to change from molecular to atomic species on increasing temperature. Comparative test of sensor response to various inorganic target gases was performed using nanocrystalline SnO2-based sensors as reference ones. Despite one order of magnitude smaller surface area, BaSnO3 displayed higher sensitivity to SO2 in comparison with SnO2. DRIFT spectroscopy revealed distinct interaction routes of the oxides surfaces with SO2. Barium-promoted sulfate formation favoring target molecules oxidation was found responsible for the increased BaSnO3 sensitivity to ppm-range concentrations of SO2 in air. PMID:28793573

  15. Lateral Flow Assay Based on Paper-Hydrogel Hybrid Material for Sensitive Point-of-Care Detection of Dengue Virus.

    PubMed

    Choi, Jane Ru; Yong, Kar Wey; Tang, Ruihua; Gong, Yan; Wen, Ting; Yang, Hui; Li, Ang; Chia, Yook Chin; Pingguan-Murphy, Belinda; Xu, Feng

    2017-01-01

    Paper-based devices have been broadly used for the point-of-care detection of dengue viral nucleic acids due to their simplicity, cost-effectiveness, and readily observable colorimetric readout. However, their moderate sensitivity and functionality have limited their applications. Despite the above-mentioned advantages, paper substrates are lacking in their ability to control fluid flow, in contrast to the flow control enabled by polymer substrates (e.g., agarose) with readily tunable pore size and porosity. Herein, taking the benefits from both materials, the authors propose a strategy to create a hybrid substrate by incorporating agarose into the test strip to achieve flow control for optimal biomolecule interactions. As compared to the unmodified test strip, this strategy allows sensitive detection of targets with an approximately tenfold signal improvement. Additionally, the authors showcase the potential of functionality improvement by creating multiple test zones for semi-quantification of targets, suggesting that the number of visible test zones is directly proportional to the target concentration. The authors further demonstrate the potential of their proposed strategy for clinical assessment by applying it to their prototype sample-to-result test strip to sensitively and semi-quantitatively detect dengue viral RNA from the clinical blood samples. This proposed strategy holds significant promise for detecting various targets for diverse future applications.

  16. Ageing of nickel used as sensitive material for early detection of sudomotor dysfunction

    NASA Astrophysics Data System (ADS)

    Ayoub, Hanna; Lair, Virginie; Griveau, Sophie; Galtayries, Anouk; Brunswick, Philippe; Bedioui, Fethi; Cassir, Michel

    2012-01-01

    The surface ageing of nickel electrodes was studied in the frame of the development of non-invasive biomedical devices, dedicated to the detection of sudomotor dysfunction manifested by an alteration of the ionic balance in human sweat. In this kind of technology, low voltage potentials with variable amplitudes are applied to nickel electrodes, placed on skin regions with a high density of sweat glands, and the electrical responses are measured. The trick is that nickel electrodes play alternately the role of anode and cathode, thus the analysis of the temporal evolution of the physico-chemical properties of nickel is of prime importance to ensure the good performance of the device. Electrochemical measurements coupled to surface chemical characterizations (X-ray photoelectron spectroscopy (XPS), Time of Flight-Secondary Ion Mass Spectrometry (ToF-SIMS)) were performed on pure Ni samples, immersed in buffered chloride solutions mimicking human sweat. The shapes of voltammograms, recorded in a restricted anodic potential range, show that the nickel surface was gradually passivated as a function of the number of scans. This was confirmed by XPS data, with the formation of a 1 nm thick duplex layer composed by nickel hydroxide (outermost layer) and nickel oxide (inner layer). In a negative extended potential range, though the electrochemical behavior of electrodes was not modified upon cycling the potential, XPS data show that the inner layer was thickening, indicating a surface degradation of the nickel electrode. Below pitting potentials, adsorbed chloride was only hardly detected by XPS, and the surface composition of the nickel samples was similar after treatments in chloride or chloride-free buffered solutions. In a larger potential range enabling to reach the breakdown potential, the highly chemically sensitive ToF-SIMS characterization pointed out that the surface concentration of adsorbed chloride was higher in pits than elsewhere on the surface sample.

  17. Equivalence of superspace groups

    PubMed Central

    van Smaalen, Sander; Campbell, Branton J.; Stokes, Harold T.

    2013-01-01

    An algorithm is presented which determines the equivalence of two settings of a (3 + d)-dimensional superspace group (d = 1, 2, 3). The algorithm has been implemented as a web tool on , providing the transformation of any user-given superspace group to the standard setting of this superspace group in . It is shown how the standard setting of a superspace group can be directly obtained by an appropriate transformation of the external-space lattice vectors (the basic structure unit cell) and a transformation of the internal-space lattice vectors (new modulation wavevectors are linear combinations of old modulation wavevectors plus a three-dimensional reciprocal-lattice vector). The need for non-standard settings in some cases and the desirability of employing standard settings of superspace groups in other cases are illustrated by an analysis of the symmetries of a series of compounds, comparing published and standard settings and the transformations between them. A compilation is provided of standard settings of compounds with two- and three-dimensional modulations. The problem of settings of superspace groups is discussed for incommensurate composite crystals and for chiral superspace groups. PMID:23250064

  18. Equivalence of superspace groups.

    PubMed

    van Smaalen, Sander; Campbell, Branton J; Stokes, Harold T

    2013-01-01

    An algorithm is presented which determines the equivalence of two settings of a (3 + d)-dimensional superspace group (d = 1, 2, 3). The algorithm has been implemented as a web tool findssg on SSG(3+d)D, providing the transformation of any user-given superspace group to the standard setting of this superspace group in SSG(3+d)D. It is shown how the standard setting of a superspace group can be directly obtained by an appropriate transformation of the external-space lattice vectors (the basic structure unit cell) and a transformation of the internal-space lattice vectors (new modulation wavevectors are linear combinations of old modulation wavevectors plus a three-dimensional reciprocal-lattice vector). The need for non-standard settings in some cases and the desirability of employing standard settings of superspace groups in other cases are illustrated by an analysis of the symmetries of a series of compounds, comparing published and standard settings and the transformations between them. A compilation is provided of standard settings of compounds with two- and three-dimensional modulations. The problem of settings of superspace groups is discussed for incommensurate composite crystals and for chiral superspace groups.

  19. Physeal bar equivalent.

    PubMed

    Peterson, Hamlet A; Shaughnessy, William J; Stans, Anthony A

    2016-09-29

    Premature partial physeal arrest without the formation of an osseous bar - physeal bar equivalent (PBE) - is uncommon. Four children with a PBE had an infection near the distal femoral physis before the age of 11 months. Some growth was achieved after resection of the PBE in each case. Of two cases diagnosed and treated early, one required only contralateral physeal arrests to achieve limb-length equality at maturity. The other, currently 8 years and 4 months old, has a 1.1-cm limb-length discrepancy 6 years after PBE resection and will require observation until maturity. Of two cases diagnosed and treated late, one required ipsilateral femoral lengthening and contralateral femoral shortening and physeal arrests to treat the limb-length discrepancy and angular deformity. The other, currently 7 years and 1 month old, has a 4.8-cm discrepancy and will need future surgical limb-length equalization. Early recognition and treatment of PBE is required to avoid severe limb-length inequality and angular deformity.

  20. Biomonitoring Equivalents for molybdenum.

    PubMed

    Hays, Sean M; Macey, Kristin; Poddalgoda, Devika; Lu, Ming; Nong, Andy; Aylward, Lesa L

    2016-06-01

    Molybdenum is an essential trace element for mammalian, plant, and other animal systems. The Institute of Medicine (IOM) has established an Estimated Average Requirement (EAR) to assure sufficient molybdenum intakes for human populations; however excessive exposures can cause toxicity. As a result, several agencies have established exposure guidance values to protect against molybdenum toxicity, including a Reference Dose (RfD), Tolerable Daily Intake (TDI) and a Tolerable Upper Intake Level (UL). Biomonitoring for molybdenum in blood or urine in the general population is being conducted by the Canadian Health Measures Survey (CHMS) and the U.S. National Health and Nutrition Examination Survey (NHANES). Using pharmacokinetic data from controlled human dosing studies, Biomonitoring Equivalents (BEs) were calculated for molybdenum in plasma, whole blood, and urine associated with exposure guidance values set to protect against both nutritional deficits and toxicity. The BEEAR values in plasma, whole blood and urine are 0.5, 0.45 and 22 μg/L, respectively. The BEs associated with toxicity range from 0.9 to 31 μg/L in plasma, 0.8-28 μg/L in whole blood and 200-7500 μg/L in urine. These values can be used to interpret molybdenum biomonitoring data from a nutritional and toxicity perspective. Copyright © 2016. Published by Elsevier Inc.

  1. Sensitivity of a bubble growth to the cheese material properties during ripening

    NASA Astrophysics Data System (ADS)

    Fokoua, G.; Grenier, D.; Lucas, T.

    2016-10-01

    In this study, a model of transport phenomena describes a single bubble growth in semi-hard cheese. Carbon dioxide production, its transport to the bubble interface, equilibrium laws and mechanics were coupled. Semi-hard cheese mainly behaves as elastic when loads are quickly applied to a piece of cheese like during chewing (few seconds). However, when slowly loaded with increasing gas pressure during ripening in warm room, the mechanical cheese behavior can be simply modelled as a viscous material (Grenier et al. [9]). It is true, as long as viscosity remains low compared to the rate of gas production. This paper investigates a wider range of viscosity (from core η = 6.32 × 107 Pa.s to rind η = 2.88 × 108 Pa.s) than that used in previous studies. FEM simulations have shown that higher viscosities encountered close to the rind of a cheese block can partly explain the increase in gas pressure within bubbles from the core to the rind (up to 3.4 kPa). These results confirm that mechanics does not really control the evolution of bubble volume in cheese. However, mechanics can explain greater pressure observed close to the rind even if gas production is lower than at core.

  2. Experimental study of temperature-sensitive chitosan/β-glycerophosphate embolic material in embolizing the basicranial rete mirabile in swines

    PubMed Central

    NING, XIANBIN; ZHAO, CHANGFU; PANG, JINFENG; DING, ZHAOYI; WANG, YUBO; XU, KAN; CHEN, HAO; LI, BINGWEI; LUO, QI

    2015-01-01

    The aim of the present study was to evaluate the feasibility of the non-adhesive temperature-sensitive liquid embolic material, chitosan/β-glycerophosphate (C/GP), in embolizing the basicranial rete mirabile (REM) in a swine model of cerebral arteriovenous malformation (cAVM). A total of 24 domestic swines were used as the experimental animals, among which 12 pigs underwent direct embolization of one side of the REM, while the other 12 pigs underwent embolization of the bilateral REM following anastomosis of the carotid artery and jugular vein. A super-selective microcatheter was introduced into the REM during the embolization procedure, and the C/GP hydrogel was injected until an image of the REM disappeared in the angiography examination. Further angiography examinations were performed after 2 and 6 weeks, and histological examination of the REM was performed after 6 weeks. Of the 24 domestic swines, 23 cases underwent successful thrombosis. Convulsions occurred in one case and that pig died during the embolization procedure. Following embolization, the angiography observations revealed that the embolized REM was no longer able to be developed, and adhesion of the microcatheter tip with the embolic agent did not occur. In addition, no apparent revascularization was observed in the angiography examinations performed at weeks 2 and 6. Therefore, the current preliminary study indicated that use of the non-adhesive temperature-sensitive embolic material was feasible for the embolization of cAVM; thus, C/GP may be used as an ideal embolic material for the treatment of cAVM. PMID:26170955

  3. Furazans with Azo Linkages: Stable CHNO Energetic Materials with High Densities, Highly Energetic Performance, and Low Impact and Friction Sensitivities.

    PubMed

    Qu, Yanyang; Zeng, Qun; Wang, Jun; Ma, Qing; Li, Hongzhen; Li, Haibo; Yang, Guangcheng

    2016-08-22

    Various highly energetic azofurazan derivatives were synthesized by simple and efficient chemical routes. These nitrogen-rich materials were fully characterized by FTIR spectroscopy, elemental analysis, multinuclear NMR spectroscopy, and high-resolution mass spectrometry. Four of them were further confirmed structurally by single-crystal X-ray diffraction. These compounds exhibit high densities, ranging from 1.62 g cm(-3) up to a remarkably high 2.12 g cm(-3) for nitramine-substituted azofurazan DDAzF (2), which is the highest yet reported for an azofurazan-based CHNO energetic compound and is a consequence of the formation of strong intermolecular hydrogen-bonding networks. From the heats of formation, calculated with Gaussian 09, and the experimentally determined densities, the energetic performances (detonation pressure and velocities) of the materials were ascertained with EXPLO5 v6.02. The results suggest that azofurazan derivatives exhibit excellent detonation properties (detonation pressures of 21.8-46.1 GPa and detonation velocities of 6602-10 114 m s(-1) ) and relatively low impact and friction sensitivities (6.0-80 J and 80-360 N, respectively). In particular, they have low electrostatic spark sensitivities (0.13-1.05 J). These properties, together with their high nitrogen contents, make them potential candidates as mechanically insensitive energetic materials with high-explosive performance. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Experimental study of temperature-sensitive chitosan/β-glycerophosphate embolic material in embolizing the basicranial rete mirabile in swines.

    PubMed

    Ning, Xianbin; Zhao, Changfu; Pang, Jinfeng; Ding, Zhaoyi; Wang, Yubo; Xu, Kan; Chen, Hao; Li, Bingwei; Luo, Q I

    2015-07-01

    The aim of the present study was to evaluate the feasibility of the non-adhesive temperature-sensitive liquid embolic material, chitosan/β-glycerophosphate (C/GP), in embolizing the basicranial rete mirabile (REM) in a swine model of cerebral arteriovenous malformation (cAVM). A total of 24 domestic swines were used as the experimental animals, among which 12 pigs underwent direct embolization of one side of the REM, while the other 12 pigs underwent embolization of the bilateral REM following anastomosis of the carotid artery and jugular vein. A super-selective microcatheter was introduced into the REM during the embolization procedure, and the C/GP hydrogel was injected until an image of the REM disappeared in the angiography examination. Further angiography examinations were performed after 2 and 6 weeks, and histological examination of the REM was performed after 6 weeks. Of the 24 domestic swines, 23 cases underwent successful thrombosis. Convulsions occurred in one case and that pig died during the embolization procedure. Following embolization, the angiography observations revealed that the embolized REM was no longer able to be developed, and adhesion of the microcatheter tip with the embolic agent did not occur. In addition, no apparent revascularization was observed in the angiography examinations performed at weeks 2 and 6. Therefore, the current preliminary study indicated that use of the non-adhesive temperature-sensitive embolic material was feasible for the embolization of cAVM; thus, C/GP may be used as an ideal embolic material for the treatment of cAVM.

  5. CTE measurement setup with 10 ppb/K sensitivity for characterizing lightweight and highly stable materials for space applications

    NASA Astrophysics Data System (ADS)

    Spannagel, Ruven; Gohlke, Martin; Schuldt, Thilo; Johann, Ulrich; Weise, Dennis; Braxmaier, Claus

    2012-09-01

    Structural materials with extremely low coecient of thermal expansion (CTE) are crucial to enable ultimate accuracy in terrestrial as well as in space-based optical metrology due to minimized temperature dependency. Typical materials, in particular in the context of space-based instrumentation are carbon-ber reinforced plastics (CFRP), C/SiC, and glass ceramics, e.g. Zerodur, ULE or Clearceram. To determine the CTE of various samples with high accuracy we utilize a highly symmetric heterodyne interferometer with a noise level below 2 pm√Hz at frequencies above 0.1 Hz. A sample tube made out of the material under investigation is vertically mounted in an ultra-stable support made of Zerodur. Measurement and reference mirrors of the interferometer are supported inside the tube using thermally compensated mounts made of Invar36. For determination of the CTE, a sinusoidal temperature variation is radiatively applied to the tube. One of the essential systematic limitations is a tilt of the entire tube as a result of temperature variation. This tilt can simultaneously be measured by the DWS technique and can be used to correct the measurement. Using a Zerodur tube as a reference, it is shown that this eect can be reduced in post processing to achieve a minimum CTE measurement sensitivity <10 ppb/K.

  6. Assessing the cultural in culturally sensitive printed patient-education materials for Chinese Americans with type 2 diabetes.

    PubMed

    Ho, Evelyn Y; Tran, Henrietta; Chesla, Catherine A

    2015-01-01

    Type 2 diabetes affects Chinese Americans at an alarming rate. To address this health disparity, research in the area of cultural sensitivity and health literacy provides useful guidelines for creating culturally appropriate health education. In this article, we use discourse analysis to examine a group of locally available, Chinese- and English-language diabetes print documents from a surface level and deep structure level of culture. First, we compared these documents to research findings about printed health information to determine whether and how these documents apply current best practices for health literacy and culturally appropriate health communication. Second, we examined how diabetes as a disease and diabetes management is being constructed. The printed materials addressed surface level culture through the use of Chinese language, pictures, foods, and exercises. From a deeper cultural level, the materials constructed diabetes management as a matter of measurement and control that contrasted with previous research suggesting an alternative construction of balance. A nuanced assessment of both surface and deeper levels of culture is essential for creating health education materials that are more culturally appropriate and can lead to increased health literacy and improved health outcomes.

  7. Efficiency enhancement in dye-sensitized solar cells with down conversion material ZnO: Eu3+, Dy3+

    NASA Astrophysics Data System (ADS)

    Yao, Nannan; Huang, Jinzhao; Fu, Ke; Liu, Shiyou; E, Dong; Wang, Yanhao; Xu, Xijin; Zhu, Min; Cao, Bingqiang

    2014-12-01

    The down conversion (DC) material ZnO: Eu3+, Dy3+ are synthesized by precipitation method and used to prepare the photo anode of dye-sensitized solar cells (DSSCs). The effects of down conversion material on the photoelectric performance of the DSSC were characterized by the X-ray diffraction (XRD), photoluminescence (PL), scanning electron microscope (SEM), current-voltage (I-V) curve, incident-photon-to-current conversion efficiency (IPCE) and UV-vis-NIR absorption spectroscopy. In this paper, Eu3+, Dy3+ codoped ZnO excited by from UV to blue light converts blue to red light emission, corresponding to the absorption region of the dye (N719). At the concentration 1.75% of ZnO: Eu3+, Dy3+ (weight ratio of DC to TiO2), the short-circuit current density and conversion efficiency of the DSSCs reached to the optimal values: 8.92 mA cm-2 and 4.48%, about 212% and 245% higher than with pure TiO2 and about 91.4% and 105% higher than with TiO2/graphene (G) structure, respectively. The research result reveals that the application of DC material can improve the efficiency of DSSCs.

  8. The Otto-engine-equivalent vehicle concept

    NASA Technical Reports Server (NTRS)

    Dowdy, M. W.; Couch, M. D.

    1978-01-01

    A vehicle comparison methodology based on the Otto-Engine Equivalent (OEE) vehicle concept is described. As an illustration of this methodology, the concept is used to make projections of the fuel economy potential of passenger cars using various alternative power systems. Sensitivities of OEE vehicle results to assumptions made in the calculational procedure are discussed. Factors considered include engine torque boundary, rear axle ratio, performance criteria, engine transient response, and transmission shift logic.

  9. Biomonitoring equivalents for deltamethrin.

    PubMed

    Aylward, Lesa L; Krishnan, Kannan; Kirman, Christopher R; Nong, Andy; Hays, Sean M

    2011-07-01

    Measured concentrations of chemicals in blood or urine in biomonitoring studies provide an integrated reflection of exposures to chemicals via multiple routes and pathways. The potential significance of the measured concentrations of chemicals in the context of existing toxicology data and risk assessments can be assessed if chemical-specific quantitative screening criteria are available. This work presents the derivation of Biomonitoring Equivalents (BEs) for deltamethrin, a synthetic Type II pyrethroid. BEs are estimates of biomarker concentrations that are consistent with risk assessment-based exposure guidance values such as reference doses or acceptable daily intakes. BE values were derived for deltamethrin based on two biomarkers: deltamethrin in plasma and 3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane carboxylic acid (DBCA), a specific metabolite, in urine. BE values for deltamethrin in plasma were based on extrapolation from measured deltamethrin concentrations in plasma in rats under conditions consistent with the Point of Departure in the critical study underlying the USEPA RfD. BE values for DBCA in urine were derived based on pharmacokinetic data from a study in human volunteers on the urinary excretion of deltamethrin and metabolites. BE values for deltamethrin in plasma corresponding to the USEPA RfD for adults and children are 20 and 2μg/L, respectively. BE values for DBCA in urine corresponding to the adult and child-specific RfDs are 50 and 7μg/L, respectively. The urinary BE value corresponding to the ADI established by the European Commission and the Joint Meeting on Pesticide Residues is 60μg/L (as DBCA in urine). These values can be used to screen biomonitoring data in the context of current risk assessments for detlamethrin. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Biomonitoring Equivalents for selenium.

    PubMed

    Hays, Sean M; Macey, Kristin; Nong, Andy; Aylward, Lesa L

    2014-10-01

    Selenium is an essential nutrient for human health with a narrow range between essentiality and toxicity. Selenium is incorporated into several proteins that perform important functions in the body. With insufficient selenium intake, the most notable effect is Keshan disease, an endemic cardiomyopathy in children. Conversely, excessive selenium intake can result in selenosis, manifested as brittle nails and hair and gastro-intestinal disorders. As such, guidance values have been established to protect against both insufficient and excessive selenium exposures. Dietary Reference Intakes (DRIs) have been established as standard reference values for nutritional adequacy in North America. To protect against selenosis resulting from exposure to excessive amounts of selenium, several government and non-governmental agencies have established a range of guidance values. Exposure to selenium is primarily through the diet, but monitoring selenium intake is difficult. Biomonitoring is a useful means of assessing and monitoring selenium status for both insufficient and excessive exposures. However, to be able to interpret selenium biomonitoring data, levels associated with both DRIs and toxicity guidance values are required. Biomonitoring Equivalents (BEs) were developed for selenium in whole blood, plasma and urine. The BEs associated with assuring adequate selenium intake (Estimated Average Requirements - EAR) are 100, 80 and 10μg/L in whole blood, plasma and urine, respectively. The BEs associated with protection against selenosis range from 400 to 480μg/L in whole blood, 180-230μg/L in plasma, and 90-110μg/L in urine. These BE values can be used by both regulatory agencies and public health officials to interpret selenium biomonitoring data in a health risk context.

  11. Comparisons of LET Distributions for Protons with Energies between50 and 200 MeV Determined Using a Spherical Tissue-EquivalentProportional Counter (TEPC) and a Position-Sensitive Silicon Spectrometer(RRMD-III)

    SciTech Connect

    Borak, Thomas B.; Doke, Tadayoshi; Fuse, T.; Guetersloh, StephenB.; Heilbronn, Lawrence H.; Hara, K.; Moyers, Michael; Suzuki, S.; Taddei, Phillip; Terasawa, K.; Zeitlin, Cary J.

    2004-12-01

    Experiments have been performed to measure the response of a spherical tissue-equivalent proportional counter (TEPC) and a silicon-based LET spectrometer (RRMD-III) to protons with energies ranging from 50 200 MeV. This represents a large portion of the energy distribution for trapped protons encountered by astronauts in low-Earth orbit. The beam energies were obtained using plastic polycarbonate degraders with a monoenergetic beam that was extracted from a proton synchrotron. The LET spectrometer provided excellent agreement with the expected LET distribution emerging from the energy degraders. The TEPC cannot measure the LET distribution directly. However, the frequency mean value of lineal energy, y bar f, provided a good approximation to LET. This is in contrast to previous results for high-energy heavy ions wherey barf underestimated LET, whereas the dose-averaged lineal energy, y barD, provided a good approximation to LET.

  12. Preparation, characterization and gas sensitivity of polypyrrole/γ-Fe{sub 2}O{sub 3} hybrid materials

    SciTech Connect

    Geng, Lina; Wu, Shihua

    2013-10-15

    Graphical abstract: - Highlights: • PPy/γ-Fe{sub 2}O{sub 3} hybrid materials were prepared by sol–gel polymerization in situ. • Different reactant molar ratios resulted in different microstructures of γ-Fe{sub 2}O{sub 3} and molecular weights of PPy. • PPy/γ-Fe{sub 2}O{sub 3} hybrids had selectivity for NH{sub 3} gases at low temperatures (<100 °C). • The sensing mechanism was suggested to be related to the existence of p–n heterojunctions in the PPy/γ-Fe{sub 2}O{sub 3} hybrid material. - Abstract: Polypyrrole (PPy)/γ-Fe{sub 2}O{sub 3} hybrid materials were prepared by sol–gel polymerization in situ and characterized by Fourier transform infrared (FT-IR), X-ray powder diffraction (XRD), thermogravimetric and differential thermal analysis (TG–DTA) and high-resolution transmission electron microscope (HRTEM). The gas sensitivities in CO, H{sub 2}, NH{sub 3}, ethanol or acetone atmospheres were determined at 30 °C, 60 °C and 90 °C. FT-IR and XRD patterns suggest that ferric oxide in the hybrids was γ-Fe{sub 2}O{sub 3}, with a diameter of approximately 5 nm. TG–DTA and HRTEM analyses showed that different reactant molar ratios of pyrrole monomer: Fe(NO{sub 3}){sub 3}·9H{sub 2}O resulted in different microstructures of γ-Fe{sub 2}O{sub 3} and molecular weights of PPy. An increased amount of Fe(NO{sub 3}){sub 3}·9H{sub 2}O increased the degree of uniformity of the molecular weight of PPy and resulted in a change of γ-Fe{sub 2}O{sub 3} microstructure from granular to stick particles. The results of gas sensitivities showed that the PPy/γ-Fe{sub 2}O{sub 3} hybrids exhibited high sensitivity to NH{sub 3} at mild operating temperature (<100 °C). Furthermore, the sensing mechanism was also discussed.

  13. Testing the weak equivalence principle

    NASA Astrophysics Data System (ADS)

    Nobili, Anna M.; Comandi, Gian Luca; Pegna, Raffaello; Bramanti, Donato; Doravari, Suresh; Maccarone, Francesco; Lucchesi, David M.

    2010-01-01

    The discovery of Dark Energy and the fact that only about 5% of the mass of the universe can be explained on the basis of the current laws of physics have led to a serious impasse. Based on past history, physics might indeed be on the verge of major discoveries; but the challenge is enormous. The way to tackle it is twofold. On one side, scientists try to perform large scale direct observations and measurements - mostly from space. On the other, they multiply their efforts to put to the most stringent tests ever the physical theories underlying the current view of the physical world, from the very small to the very large. On the extremely small scale very exciting results are expected from one of the most impressive experiments in the history of mankind: the Large Hadron Collider. On the very large scale, the universe is dominated by gravity and the present impasse undoubtedly calls for more powerful tests of General Relativity - the best theory of gravity to date. Experiments testing the Weak Equivalence Principle, on which General Relativity ultimately lies, have the strongest probing power of them all; a breakthrough in sensitivity is possible with the “Galileo Galilei” (GG) satellite experiment to fly in low Earth orbit.

  14. Nanostructured materials and their charge transport properties in photoanodes of dye sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Ponsaing, Anita Kristine

    Since the big progress of dye sensitized solar cells (DSCs) by adopting TiO2 nanoparticles for a photoanode in 1991, DSCs have been intensively studied as an alternative to conventional Si-based solar cells. As a main component of DSCs, a photoanode composed of a nanostructured semiconducting oxide network plays a significant role in determining performances of DSCs in terms of light harvesting efficiency (LHE) and charge collection efficiency related to charge transport and recombination. Nanomaterials with various morphologies, such as particles, rods and tubes have been fabricated and investigated to improve performances of DSCs. Among them, submicrometer-sized aggregates of nanocrystallites have demonstrated to be promising as a photoanode of DSCs for higher power conversion efficiency. Such hierarchical structures make it possible to have both high specific surface area for dye molecule adsorption and internal light scattering within the photoanode, leading to a much enhanced LHE. This work focused on the surface modification and charge transport characterization of such hierarchically structured photoanodes. First, a core-shell configuration was fabricated by atomic layer deposition (ALD) process, which was achieved by depositing ultrathin TiO2 layer on inner surface of ZnO aggregate film in which the TiO2 shell was anticipated to act as a chemical and energy barrier. Although the ALD-TiO2 coating failed to improve chemical stability of the ZnO aggregate against to an acidic dye solution due to the ultrathin thickness (< 1 nm), the ALD-TiO2 shell layer effectively suppressed charge recombination at the interface. As a result of the reduced charge recombination, Voc, and FF of DSCs were increased, leading to 20 % enhancement of power conversion efficiency. Second, effects of annealing temperatures on ALD-TiO2 coated aggregates of ZnO nanocrystallites were investigated in terms of sintering behavior and charge transport. 350 °C as the maximum temperature was

  15. Temperature sensitivity of CO2, CH4, CO, and H2 release during photodegradation of organic material

    NASA Astrophysics Data System (ADS)

    Lee, H.; Rahn, T.; Throop, H.

    2012-04-01

    Recent studies suggest that photochemical breakdown (hereafter 'photodegradation') of plant material by ultraviolet (UV) radiation may circumvent biotic decomposition and account for as much as a third of decomposition in arid and semiarid ecosystems. Current knowledge of the mechanism by which UV breaks down plant-derived carbon compounds such as cellulose and lignin is limited. Previous studies suggest that photodegradation may not only release CO2, but also CO and CH4, and that gas production may be sensitive to temperature. We established a laboratory experiment to test the temperature sensitivity of greenhouse gases (CO2 and CH4) and indirect greenhouse gases (CO and H2) during photodegradation of plant material. The photochemical reaction was induced using a 300 W xenon lamp solar simulator in a closed quartz chamber connected to a high resolution wavelength-scanned cavity ringdown spectrometer for CO2-CH4 and a reduced compound photometer gas chromatograph for CO and H2. The temperature was controlled using a water bath connected to a chiller/heater below the chamber to control chamber temperatures at 15, 25, 35, 45, and 55°C. We compared emission rates from two artificial materials that were high in lignin (basswood sheet) and cellulose (filter paper) and leaves of four species of plant litter collected from their native habitats in the southwestern U.S.: dried leaflets of velvet mesquite, culms and leaves of Indian ricegrass (C4 grass) and little bluestem grass (C3 grass), and piñon pine needles. The rates of CO2 and CO emissions from photodegradation ranged from 3-67 μmol CO2-C m-2 hr-1 and 2-34 μmol CO-C m-2 hr-1 and were positively correlated to temperature for all materials (magnitude of fluxes: basswood > leaf materials > filter paper). In contrast, the rate of CH4 and H2 ranged from 0-0.5 μmol CH4-C m-2 hr-1 and 0-4 μmol H2 m-2 hr-1, but the temperature responses varied among materials. For instance, the rate of CH4 and H2 emissions were

  16. Temperature sensitivity of CO2, CH4, CO, and H2 release during photodegradation of organic material

    NASA Astrophysics Data System (ADS)

    Lee, H.; Rahn, T.; Throop, H. L.

    2012-12-01

    Recent studies suggest that photochemical breakdown (hereafter 'photodegradation') of plant material by ultraviolet (UV) radiation may circumvent biotic decomposition and account for as much as a third of decomposition in arid and semiarid ecosystems. Current knowledge of the mechanism by which UV breaks down plant-derived carbon compounds such as cellulose and lignin is limited. Previous studies suggest that photodegradation may not only release CO2, but also CO and CH4, and that gas production may be sensitive to temperature. We established a laboratory experiment to test the temperature sensitivity of greenhouse gases (CO2 and CH4) and indirect greenhouse gases (CO and H2) during photodegradation of plant material. The photochemical reaction was induced using a 300 W xenon lamp solar simulator in a closed quartz chamber connected to a high resolution wavelength-scanned cavity ringdown spectrometer for CO2-CH4 and a reduced compound photometer gas chromatograph for CO and H2. The temperature was controlled using a water bath connected to a chiller/heater below the chamber to control chamber temperatures at 15, 25, 35, 45, and 55°C. We compared emission rates from two artificial materials that were high in lignin (basswood sheet) and cellulose (filter paper) and leaves of four species of plant litter collected from their native habitats in the southwestern U.S.: dried leaflets of velvet mesquite, culms and leaves of Indian ricegrass (C4 grass) and little bluestem grass (C3 grass), and piñon pine needles. The rates of CO2 and CO emissions from photodegradation ranged from 3-67 μmol CO2-C m-2 hr-1 and 2-34 μmol CO-C m-2 h-1 and were positively correlated to temperature for all materials (magnitude of fluxes: basswood > leaf materials > filter paper). In contrast, the rate of CH4 and H2 ranged from 0-0.5 μmol CH4-C m-2 hr-1 and 0-4 μmol H2 m-2 hr-1, but the temperature responses varied among materials. For instance, the rate of CH4 and H2 emissions were

  17. Mesenchymal stem cells from reaming material possess high osteogenic potential and react sensitively to bone morphogenetic protein 7.

    PubMed

    Hoellig, Melanie; Westhauser, Fabian; Kornienko, Kira; Xiao, Kai; Schmidmaier, Gerhard; Moghaddam, Arash

    2017-01-26

    Femoral material harvested using the Reamer-Irrigator-Aspirator (RIA) system is an alternative source for autogenous bone material in the treatment of non-unions, especially in combination with bone morphogenetic proteins (BMP). So far, there is no in vivo evidence of BMP-7 interacting with mesenchymal stem cells (MSCs) from RIA material (RIA-MSCs) and iliac crest autogenous bone (BMSCs). The aim of this study was to compare their osteogenic potential when stimulated with BMP-7 in vivo. RIA-MSC and BMSC from 11 donors were isolated and the character of MSCs was investigated in vitro. Constructs consisting of MSC, β-tricalcium phosphate and 2 concentrations of BMP-7 (0.1 µg/mL and 1 µg/mL) were implanted in mice for 8 weeks. Bone formation in the constructs was analyzed quantitatively and qualitatively. All cell populations used were determined to be MSCs. The qualitative in vivo analysis showed formation of bone tissue. With regard to quantity, bone formation was significantly higher in RIA constructs without or with stimulation with 0.1 µg/mL BMP-7, compared with BMSC constructs. We found no significant differences between constructs stimulated with 1 µg/mL BMP-7. In the RIA group, we observed a significant increase in bone formation after stimulation with 0.1 µg/mL BMP-7. No significant change could be found using a higher concentration. In the BMSC group, we detected a significant increase when using 0.1 µg/mL and 1 µg/mL BMP-7. RIA material is a source of MSCs with high osteogenic potential. Our results showed that stimulation by BMP-7 leads to an increased osteogenic potential of MSCs. In this respect, RIA-MSCs reacted more sensitively than BMSCs.

  18. Design of beta-domain swapping, alpha/beta-protein, environmentally sensitive coiled coil and peptide functionalized titania materials

    NASA Astrophysics Data System (ADS)

    Nagarkar, Radhika P.

    2009-12-01

    The objective of this dissertation is to apply rational peptide design to fabricate nanomaterials via self-assembly. This has been demonstrated in structurally diverse systems with an aim of deciphering the underlying principles governing how sequence affects the peptide's ability to adopt a specific secondary structure and ultimate material properties that are realized from the association of these secondary structural elements. Several amyloidogenic proteins have been shown to self-assemble into fibrils using a mechanism known as domain swapping. Here, discreet units of secondary structure are exchanged among discreet proteins during self-assembly to form extended networks with precise three dimensional organization. The possibility of using these mechanisms to design peptides capable of controlled assembly and fibril formation leading to materials with targeted properties is explored. By altering the placement of a beta-turn sequence that varies the size and location of the exchanged strand, twisting, non-twisting and laminated fibrillar nanostructures are obtained. Hydrogels prepared from these strand swapping beta-hairpins have varied rheological properties due to differences in their fibrillar nanostructures. In a second distinct design, alpha/beta-proteins are used to prepare environmentally sensitive hydrogels. Here, multiple distinct motifs for structural integrity and dynamic response within a single self-assembling peptide allow the amyloid-like fibrils formed to controllably alter their nano-topography in response to an external stimulus such as temperature. The development of these self-assembling alpha/beta-protein motifs also necessitated the design of pH sensitive antiparallel coiled coils. Exploring the basic principles responsible for pH dependent conformational changes in coiled coils can lead to new insights in the control of protein structure and function. Lastly, this dissertation discusses the interface between biomolecules and inorganic

  19. Biomechanics of chiasmal compression: Sensitivity of the mechanical behaviors of nerve fibers to variations in material property and geometry

    NASA Astrophysics Data System (ADS)

    Wang, Xiaofei; Neely, Andrew J.; McIlwaine, Gawn G.; Lueck, Christian J.

    2016-05-01

    The mechanism of bitemporal hemianopia is still unclear. Previous research suggested that the nerve fiber packing pattern may contribute to the selective damage of nasal (crossed) nerve fibers. Numerical models were built using finite element modeling to study the biomechanics of optic nerve fibers. The sensitivity of the mechanical behaviors of the nerve fibers to variations of five parameters in the nerve fiber model were investigated using design of experiments (DOE). Results show that the crossing angle is a very significant factor that affects a wide range of responses of the model. The strain difference between the crossed and the uncrossed nerve fibers may account for the phenomenon of bitemporal hemianopia. This work also highlights the need for more accurate material properties of the tissues in the model and an improved understanding of the microstructure of the optic chiasm.

  20. String dualities and empirical equivalence

    NASA Astrophysics Data System (ADS)

    Dawid, Richard

    2017-08-01

    String dualities establish empirical equivalence between theories that often look entirely different with respect to their basic ontology and physical structure. Therefore, they represent a particularly interesting example of empirical equivalence in physics. However, the status of duality relations in string physics differs substantially from the traditional understanding of the role played by empirical equivalence. The paper specifies three important differences and argues that they are related to a substantially altered view on the underdetermination of theory building.

  1. Effects of inner materials on the sensitivity and phase depth of wireless inductive pressure sensors for monitoring intraocular pressure

    NASA Astrophysics Data System (ADS)

    Jang, Cheol-In; Shin, Kyeong-Sik; Kim, Mi Jeung; Yun, Kwang-Seok; Park, Ki Ho; Kang, Ji Yoon; Lee, Soo Hyun

    2016-03-01

    In this research, we developed wireless, inductive, pressure sensors with high sensitivity and investigated the effects of the inner materials (copper or ferrite) on the performance of the sensors. The proposed sensor is comprised of two parts, i.e., the top and the bottom parts. The top part includes a micro coil and a capacitor for the wireless transfer of data, and the bottom part includes the inner materials and a thick or thin flexible membrane to induce changes in the inductance. An anchor is used to assemble the top and bottom parts. The behavior of the sensor with copper was based on the eddy current effect, and, as the pressure increased, its resonance frequency increased, while its phase depth decreased exponentially. The principle of the sensor with ferrite was related to the effective permeability between a ferrite and a coil, and its response was the opposite of that with copper, i.e., as the pressure increased, the resonance frequency decreased linearly, and the phase depth increased linearly. These different operational mechanisms can be explained by the changes in the equations of inductance presented in this paper. After characterizing four different types of inductive pressure sensors in ambient air, one type of inductive pressure sensor was used to monitor the intraocular pressure (IOP) of a rabbit's eye as a biomedical application. The results showed that, in the animal tests, the measured responsivity and sensitivity were 16.7 kHz/mmHg and 1340 ppm/mmHg, respectively. These data indicate that the proposed sensor is a good candidate for monitoring IOP.

  2. Modeling materials and processes in hybrid/organic photovoltaics: from dye-sensitized to perovskite solar cells.

    PubMed

    De Angelis, Filippo

    2014-11-18

    CONSPECTUS: Over the last 2 decades, researchers have invested enormous research effort into hybrid/organic photovoltaics, leading to the recent launch of the first commercial products that use this technology. Dye-sensitized solar cells (DSCs) have shown clear advantages over competing technologies. The top certified efficiency of DSCs exceeds 11%, and the laboratory-cell efficiency is greater than 13%. In 2012, the first reports of high efficiency solid-state DSCs based on organohalide lead perovskites completely revolutionized the field. These materials are used as light absorbers in DSCs and as light-harvesting materials and electron conductors in meso-superstructured and flat heterojunction solar cells and show certified efficiencies that exceed 17%. To effectively compete with conventional photovoltaics, emerging technologies such as DSCs need to achieve higher efficiency and stability, while maintaining low production costs. Many of the advances in the DSC field have relied on the computational design and screening of new materials, with researchers examining material characteristics that can improve device performance or stability. Suitable modeling strategies allow researchers to observe the otherwise inaccessible but crucial heterointerfaces that control the operation of DSCs, offering the opportunity to develop new and more efficient materials and optimize processes. In this Account, we present a unified view of recent computational modeling research examining DSCs, illustrating how the principles and simulation tools used for these systems can also be adapted to study the emerging field of perovskite solar cells. Researchers have widely applied first-principles modeling to the DSC field and, more recently, to perovskite-based solar cells. DFT/TDDFT methods provide the basic framework to describe most of the desired materials and interfacial properties, and Car-Parrinello molecular dynamics allow researchers the further ability to sample local minima and

  3. Estimating equivalence with quantile regression

    USGS Publications Warehouse

    Cade, B.S.

    2011-01-01

    Equivalence testing and corresponding confidence interval estimates are used to provide more enlightened statistical statements about parameter estimates by relating them to intervals of effect sizes deemed to be of scientific or practical importance rather than just to an effect size of zero. Equivalence tests and confidence interval estimates are based on a null hypothesis that a parameter estimate is either outside (inequivalence hypothesis) or inside (equivalence hypothesis) an equivalence region, depending on the question of interest and assignment of risk. The former approach, often referred to as bioequivalence testing, is often used in regulatory settings because it reverses the burden of proof compared to a standard test of significance, following a precautionary principle for environmental protection. Unfortunately, many applications of equivalence testing focus on establishing average equivalence by estimating differences in means of distributions that do not have homogeneous variances. I discuss how to compare equivalence across quantiles of distributions using confidence intervals on quantile regression estimates that detect differences in heterogeneous distributions missed by focusing on means. I used one-tailed confidence intervals based on inequivalence hypotheses in a two-group treatment-control design for estimating bioequivalence of arsenic concentrations in soils at an old ammunition testing site and bioequivalence of vegetation biomass at a reclaimed mining site. Two-tailed confidence intervals based both on inequivalence and equivalence hypotheses were used to examine quantile equivalence for negligible trends over time for a continuous exponential model of amphibian abundance. ?? 2011 by the Ecological Society of America.

  4. Enhancing the photoelectrochemical water splitting characteristics of titanium and tungsten oxide based materials via doping and sensitization

    NASA Astrophysics Data System (ADS)

    Gakhar, Ruchi

    To better utilize solar energy for clean energy production, efforts are needed to overcome the natural diurnal variation and the diffuse nature of sunlight. Photoelectrochemical (PEC) hydrogen generation by water splitting is a promising approach to harvest solar energy. Hydrogen gas is a clean and high energy capacity fuel. However, the solar-to-hydrogen conversion efficiency is determined mainly by the properties of the materials employed as photoanodes. Improving the power-conversion efficiency of PEC water splitting requires the design of inexpensive and efficient photoanodes that have strong visible light absorption, fast charge separation, and lower charge recombination rate. In the present study, PEC characteristics of various semiconducting photoelectrodes such as TiO2, WO3 and CuWO4 were investigated. Due to the inherent wide gap, such metal oxides absorb only ultraviolet radiation. Since ultraviolet radiation only composes of 4% of the sun's spectrum, the wide band gap results in lower charge collection and efficiency. Thusto improve optical absorption and charge separation, it is necessary to modify the band gap with low band gap materials.The two approaches followed for modification of band gap are doping and sensitization. Here, TiO2 and WO3 based photoanodes were sensitized with ternary quatum dots, while doping was the primary method utilized to investigate the modification of the band gap of CuWO4. The first part of this dissertation reports the synthesis of ternary quantum dot - sensitized titania nanotube array photoelectrodes. Ternary quantum dots with varying band gaps and composition (MnCdSe, ZnCdSe and CdSSe) were tethered to the surface of TiO2 nanotubes using succcessive ionic layer adsorption and reaction (SILAR) technique. The stoichiometry of ternary quantum dots was estimated to beMn0.095Cd0.95Se, Zn0.16Cd0.84Se and CdS0.54Se0.46. The effect of varying number of sensitization cycles and annealing temperature on optical and

  5. Frequency, sensitivity, and specificity of individual signs of diverticulitis on thin-section helical CT with colonic contrast material: experience with 312 cases.

    PubMed

    Kircher, Moritz F; Rhea, James T; Kihiczak, Danylo; Novelline, Robert A

    2002-06-01

    The aim of our study was to determine the frequency, sensitivity, and specificity of the individual signs of diverticulitis using helical CT with colonic contrast material. Between March 1997 and September 1999, 312 patients with suspected diverticulitis were examined on helical CT using rectally administered colonic contrast material. CT scans that were positive for diverticulitis or indeterminate were rereviewed by two radiologists; CT interpretations were correlated with patients' clinical courses and surgical findings. One hundred fourteen (37%) of the 312 CT scans were interpreted as positive for diverticulitis; 192 scans (61%), as negative; six scans (2%), as indeterminate. Of the 114 scans that were positive for diverticulitis, 109 (96%; sensitivity 96%, specificity 91%) showed bowel wall thickening; 108 (95%; sensitivity 96%, specificity 90%), fat stranding; 104 (91%; sensitivity 91%, specificity 67%), diverticula; 57 (50%; sensitivity 50%, specificity 100%), fascial thickening; 51 (45%; sensitivity 45%, specificity 97%), free fluid; 49 (43%; sensitivity 43%, specificity 100%), inflamed diverticula; 34 (30%; sensitivity 30%, specificity 100%), free air; 18 (16%; sensitivity 16%, specificity 100%), "arrowhead" signs; nine (8%; sensitivity 8%, specificity 99%), abscesses; four (4%; sensitivity 4%, specificity 100%,), phlegmons; five (4%; sensitivity 4%, specificity 99%), intramural air; two (2%; sensitivity 2%, specificity 100%), intramural sinus tracts. Overall CT interpretation had a sensitivity of 99%, a specificity of 99%, a positive predictive value of 99%, a negative predictive value of 99%, and an overall accuracy of 99%. The two most frequent signs of diverticulitis were bowel wall thickening (96%) and fat stranding (95%). Less frequent but highly specific signs were fascial thickening (50%), free fluid (45%), and inflamed diverticula (43%).

  6. The effect of material composition of 3-dimensional graphene oxide and self-doped polyaniline nanocomposites on DNA analytical sensitivity.

    PubMed

    Yang, Tao; Chen, Huaiyin; Yang, Ruirui; Wang, Xinxing; Nan, Fuxin; Jiao, Kui

    2015-09-01

    Until now, morphology effects of 2-dimensional or 3-dimensional graphene nanocomposites and the effect of material composition on the biosensors have been rarely reported. In this paper, the various nanocomposites based on graphene oxide and self-doped polyaniline nanofibres for studying the effect of morphology and material composition on DNA sensitivity were directly reported. The isolation and dispersion of graphene oxide were realized via intercalated self-doped polyaniline and ultrasonication, where the ultrasonication prompts the aggregates of graphite oxide to break up and self-doped polyaniline to diffuse into the stacked graphene oxide. Significant electrochemical enhancement has been observed due to the existence of self-doped polyaniline, which bridges the defects for electron transfer and, in the mean time, increases the basal spacing between graphene oxide sheets. Different morphologies can result in different ssDNA surface density, which can further influence the hybridization efficiency. Compared with 2-dimensional graphene oxide, self-doped polyaniline and other morphologies of nanocomposites, 3-dimensional graphene oxide-self-doped polyaniline nanowalls exhibited the highest surface density and hybridization efficiency. Furthermore, the fabricated biosensors presented the broad detection range with the low detection limit due to the specific surface area, a large number of electroactive species, and open accessible space supported by nanowalls. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Highly Soluble p-Terphenyl and Fluorene Derivatives as Efficient Dopants in Plastic Scintillators for Sensitive Nuclear Material Detection.

    PubMed

    Sellinger, Alan; Yemam, Henok A; Mahl, Adam; Greife, Uwe; Tinkham, Jonathan; Koubek, Joshua

    2017-04-10

    Plastic scintillators are commonly used as first-line detectors for special nuclear materials. Current state-of-the-art plastic scintillators based on poly(vinyltoluene) (PVT) matrices containing high loadings (>15.0 wt%) of 2,5-diphenyloxazole (PPO) offer neutron signal discrimination in gamma radiation background (termed pulse shape discrimination, PSD), however they suffer from poor mechanical properties. In this work, a series of p-terphenyl and fluorene derivatives were synthesized and used as dopants in PVT based plastic scintillators as possible alternatives to PPO to address the mechanical property issue and to study the PSD mechanism. The derivatives were synthesized from low cost starting materials in high yields using simple chemistry. The photophysical and thermal properties were investigated for their influence on radiation sensitivity/detection performance, and mechanical stability. A direct correlation was found between the melting point of the dopants and the subsequent mechanical properties of the PVT based plastic scintillators. Select fluorene derivatives produced scintillator samples whose mechanical properties exceeded those of the commercial PPO based scintillators while producing acceptable PSD capabilities. The physical properties of the synthesized dopants were also investigated to examine their effect on the samples. Planar derivatives of fluorene were found to be highly soluble in PVT matrices with little to no aggregation induced effects.

  8. Methodological questions of creating tissue-equivalent phantoms

    NASA Technical Reports Server (NTRS)

    Kolodkin, A. V.; Popov, V. I.; Sychkov, M. A.; Nikl, I.; Erdei, M.; Eyben, O.

    1974-01-01

    On the basis of analysis and generalization of literature data, the composition of tissue equivalent plastic was justified, parameters of a standard man were determined, plaster and metal forms were created for casting dummies, and an experimental model was produced from tissue equivalent material.

  9. Saponification equivalent of dasamula taila.

    PubMed

    Saxena, R B

    1994-07-01

    Saponification equivalent values of Dasamula taila are very useful for the technical and analytical work. It gives the mean molecular weight of the glycerides and acids present in Dasamula Taila. Saponification equivalent values of Dasamula taila are reported in different packings.

  10. Test of the Equivalence Principle in an Einstein Elevator

    NASA Technical Reports Server (NTRS)

    Shapiro, Irwin I.

    2002-01-01

    The scientific goal of the experiment is to test the equality of gravitational and inertial mass (i.e., to test the Principle of Equivalence) by measuring the independence of the rate of fall of bodies from the composition of the falling body. The measurement is accomplished by measuring the relative displacement (or equivalently acceleration) of two falling bodies of different materials which are the proof masses of a differential accelerometer. The goal of the experiment is to measure the Eotvos ratio delta-g/g (differential acceleration/common acceleration) with an accuracy goal of a few parts in 10(exp 15). The estimated accuracy is about two orders of magnitude better than the present state of the art. The experiment is a null experiment in which a result different from zero will indicate a violation of the Equivalence Principle. The main goal of the study to be carried out under this grant is the flight definition of the experiment and bread boarding of critical components of the experiment that will enable us to be ready for the following phases of the project. The project involves an international cooperation in which the responsibility of the US side is the flight definition of the experimental facility while the responsibility of the non-US partners is the flight definition and laboratory prototyping of the differential acceleration detector. In summary, the experiment to be designed is for taking differential acceleration measurements with a high-sensitivity detector (the sensor) during free fall conditions lasting up to 30 s in a disturbance-free acceleration environment. The experiment strategy consists in letting the sensor free fall inside a few meters long (in the vertical direction) evacuated capsule that is falling simultaneously in the rarefied atmosphere after release from a helium balloon flying at a stratospheric altitude.

  11. Psychotropic dose equivalence in Japan.

    PubMed

    Inada, Toshiya; Inagaki, Ataru

    2015-08-01

    Psychotropic dose equivalence is an important concept when estimating the approximate psychotropic doses patients receive, and deciding on the approximate titration dose when switching from one psychotropic agent to another. It is also useful from a research viewpoint when defining and extracting specific subgroups of subjects. Unification of various agents into a single standard agent facilitates easier analytical comparisons. On the basis of differences in psychopharmacological prescription features, those of available psychotropic agents and their approved doses, and racial differences between Japan and other countries, psychotropic dose equivalency tables designed specifically for Japanese patients have been widely used in Japan since 1998. Here we introduce dose equivalency tables for: (i) antipsychotics; (ii) antiparkinsonian agents; (iii) antidepressants; and (iv) anxiolytics, sedatives and hypnotics available in Japan. Equivalent doses for the therapeutic effects of individual psychotropic compounds were determined principally on the basis of randomized controlled trials conducted in Japan and consensus among dose equivalency tables reported previously by psychopharmacological experts. As these tables are intended to merely suggest approximate standard values, physicians should use them with discretion. Updated information of psychotropic dose equivalence in Japan is available at http://www.jsprs.org/en/equivalence.tables/. [Correction added on 8 July 2015, after first online publication: A link to the updated information has been added.].

  12. Equivalence-Equivalence: Matching Stimuli with Same Discriminative Functions

    ERIC Educational Resources Information Center

    Carpentier, Franck; Smeets, Paul M.; Barnes-Holmes, Dermot

    2004-01-01

    Previous studies have shown that after being trained on A-B and A-C match-to-sample tasks, adults match not only same-class B and C stimuli (equivalence) but also BC compounds with same-class elements and with different-class elements (BC-BC). The assumption was that the BC-BC performances are based on matching equivalence and nonequivalence…

  13. Equivalence-Equivalence: Matching Stimuli with Same Discriminative Functions

    ERIC Educational Resources Information Center

    Carpentier, Franck; Smeets, Paul M.; Barnes-Holmes, Dermot

    2004-01-01

    Previous studies have shown that after being trained on A-B and A-C match-to-sample tasks, adults match not only same-class B and C stimuli (equivalence) but also BC compounds with same-class elements and with different-class elements (BC-BC). The assumption was that the BC-BC performances are based on matching equivalence and nonequivalence…

  14. The equivalent fundamental-mode source

    SciTech Connect

    Spriggs, G.D.; Busch, R.D.; Sakurai, Takeshi; Okajima, Shigeaki

    1997-02-01

    In 1960, Hansen analyzed the problem of assembling fissionable material in the presence of a weak neutron source. Using point kinetics, he defined the weak source condition and analyzed the consequences of delayed initiation during ramp reactivity additions. Although not clearly stated in Hansen`s work, the neutron source strength that appears in the weak source condition corresponds to the equivalent fundamental-mode source. In this work, we describe the concept of an equivalent fundamental-mode source and we derive a deterministic expression for a factor, g*, that converts any arbitrary source distribution to an equivalent fundamental-mode source. We also demonstrate a simplified method for calculating g* in subcritical systems. And finally, we present a new experimental method that can be employed to measure the equivalent fundamental-mode source strength in a multiplying assembly. We demonstrate the method on the zero-power, XIX-1 assembly at the Fast Critical Assembly (FCA) Facility, Japan Atomic Energy Research Institute (JAERI).

  15. Spectrophotometric and chromatographic determination of insensitive energetic materials: HNS and NTO, in the presence of sensitive nitro-explosives.

    PubMed

    Can, Ziya; Uzer, Ayşem; Tekdemir, Yasemin; Erçağ, Erol; Türker, Lemi; Apak, Reşat

    2012-02-15

    As there are no molecular spectroscopic determination methods for the most widely used insensitive energetic materials, 2,2',4,4',6,6'-hexanitrostilbene (HNS) and 3-nitro-1,2,4-triazole-5-one (NTO), in the presence of sensitive nitro-explosives, two novel spectrophotometric methods were developed. For HNS and TNT mixtures, both analytes react with dicyclohexylamine (DCHA) forming different colored charge-transfer complexes, which can be resolved by derivative spectroscopy. The spectrophotometric method for NTO measures the 416-nm absorbance of its yellow-colored Na(+)NTO(-) salt formed with NaOH. TNT, if present, is pre-extracted into IBMK as its Meisenheimer anion forming an ion-pair with the cationic surfactant cetyl pyridinium (CP(+)) in alkaline medium, whereas the unextracted NTO is determined in the aqueous phase. The molar absorptivity (ε, L mol(-1)cm(-1)) and limit of quantification (LOQ, mg L(-1)) are as follows: for HNS, ε=2.75 × 10(4) and LOQ=0.48 (in admixture with TNT); for NTO, ε=6.83 × 10(3) and LOQ=0.73. These methods were not affected from nitramines and nitrate esters in synthetic mixtures or composite explosives. The developed methods were statistically validated against HPLC, and the existing chromatographic method was modified so as to enable NTO determination in the presence of TNT. These simple, low-cost, and versatile methods can be used in criminology, remediation/monitoring of contaminated sites, and kinetic stability modeling of munitions containing desensitized energetic materials. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Redox-sensitive materials for drug delivery: targeting the correct intracellular environment, tuning release rates, and appropriate predictive systems.

    PubMed

    Phillips, Daniel J; Gibson, Matthew I

    2014-08-10

    The development of responsive drug delivery systems (DDS) holds great promise as a tool for improving the pharmacokinetic properties of drug compounds. Redox-sensitive systems are particularly attractive given the rich variety of redox gradients present in vivo. These gradients, where the circulation is generally considered oxidizing and the cellular environment is substantially more reducing, provide attractive options for targeted, specific cargo delivery. Experimental evidence suggests that a "one size fits all" redox gradient does not exist. Rather, there are subtle differences in redox potential within a cell, while the chemical nature of reducing agents in these microenvironments varies. Recent works have demonstrated an ability to modulate the degradation rate of redox-susceptible groups and, hence, provide new tools to engineer precision-targeted DDS. Modern synthetic and macromolecular chemistry provides access to a wide range of redox-susceptible architectures. However, in order to utilize these in real applications, the actual chemical nature of the redox-susceptible group, the sub-cellular location being targeted, and the redox microenvironment being encountered should be considered in detail. This is critical to avoid the over-simplification possible when using non-biological reducing agents, which may provide inaccurate kinetic information, and to ensure these materials can be advanced beyond simple "on/off" systems. Furthermore, a strong case can be made for the use of biorelevant reducing agents such as glutathione when demonstrating a materials redox response. A further understanding of the complexities of the extra- and intracellular microenvironments would greatly assist with the design and application of DDS.

  17. Morita equivalence of noncommutative supertori

    NASA Astrophysics Data System (ADS)

    Chang-Young, Ee; Kim, Hoil; Nakajima, Hiroaki

    2010-06-01

    In this paper we study the extension of Morita equivalence of noncommutative tori to the supersymmetric case. The structure of the symmetry group yielding Morita equivalence appears to be intact but its parameter field becomes supersymmetrized having both body and soul parts. Our result is mainly in the two dimensional case in which noncommutative supertori have been constructed recently: The group SO(2,2,VZ0), where VZ0 denotes Grassmann even number whose body part belongs to Z, yields Morita equivalent noncommutative supertori in two dimensions.

  18. Morita equivalence of noncommutative supertori

    SciTech Connect

    Chang-Young, Ee; Kim, Hoil; Nakajima, Hiroaki

    2010-06-15

    In this paper we study the extension of Morita equivalence of noncommutative tori to the supersymmetric case. The structure of the symmetry group yielding Morita equivalence appears to be intact but its parameter field becomes supersymmetrized having both body and soul parts. Our result is mainly in the two dimensional case in which noncommutative supertori have been constructed recently: The group SO(2,2,V{sub Z}{sup 0}), where V{sub Z}{sup 0} denotes Grassmann even number whose body part belongs to Z, yields Morita equivalent noncommutative supertori in two dimensions.

  19. A new strategy for storage and transportation of sensitive high-energy materials: guest-dependent energy and sensitivity of 3D metal-organic-framework-based energetic compounds.

    PubMed

    Zhang, Sheng; Liu, Xiangyu; Yang, Qi; Su, Zhiyong; Gao, Wenjuan; Wei, Qing; Xie, Gang; Chen, Sanping; Gao, Shengli

    2014-06-23

    Reaction of Co(II) with the nitrogen-rich ligand N,N-bis(1H-tetrazole-5-yl)-amine (H2bta) leads to a mixed-valence, 3D, porous, metal-organic framework (MOF)-based, energetic material with the nitrogen content of 51.78%, [Co9(bta)10(Hbta)2(H2O)10]n⋅(22 H2O)n (1). Compound 1 was thermohydrated to produce a new, stable, energetic material with the nitrogen content of 59.85% and heat of denotation of 4.537 kcal cm(-3), [Co9(bta)10(Hbta)2(H2O)10]n (2). Sensitivity tests show that 2 is more sensitivity to external stimuli than 1, reflecting guest-dependent energy and sensitivity of 3D, MOF-based, energetic materials. Less-sensitive 1 can be regarded as a more safe form for storage and transformation to sensitive 2. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Solid-state dye-sensitized solar cells based on spirofluorene (spiro-OMeTAD) and arylamines as hole transporting materials.

    PubMed

    Hsu, Chih-Yu; Chen, Yung-Chung; Lin, Ryan Yeh-Yung; Ho, Kuo-Chuan; Lin, Jiann T

    2012-11-07

    Dye-sensitized solar cells are a promising solar technology because of their low cost, reliability, and high efficiency, compared with silicon-based solar cells. Efforts over the last two decades have increased solar cell efficiency to 12% based on liquid electrolytes, and more research on solid-state devices is necessary to determine their practical usage and long-term stability. The development of solid-state devices has achieved an overall efficiency over 7% using hole transporting materials. This study reviews current progress on hole transporting materials, sensitizers, and mesoporous TiO(2) in solid-state dye-sensitized solar cells using small organic molecules as the hole transporting material. This study also discusses the key factors, such as molecular structure design and interfacial problems, affecting device performance.

  1. Photovoltaic performance of nanoporous TiO2 replicas synthesized from mesoporous materials for dye-sensitized solar cells.

    PubMed

    Hwang, Kyung-Jun; Yoo, Seung-Joon; Kim, Sung-Soo; Kim, Ji-Man; Shim, Wang-Geun; Kim, Sun-Il; Lee, Jae-Wook

    2008-10-01

    For dye-sensitized solar cell (DSSC), highly ordered nanoporous TiO2 materials with crystalline frameworks were successfully synthesized from different silica templates including SBA-15, KIT-6 and MSU-H. A photoelectrode in DSSC was fabricated by adsorbing cis-bis(isothiocyanato)bis(2,2'-bipyridyl-4,4'-dicarboxylato)-ruthenium(II)bis-tetrabutylammonium dye (N719) onto the prepared TiO2 nanoparticles. The samples were characterized by XRD, TEM, FE-SEM, AFM and Brunauer-Emmett-Teller (BET), and FT-IR analysis. An investigation of the influence of the bonding structure of N719 dye and nanoporous TiO2 on the photovoltaic performance of DSSC revealed that the bonding structure of N719 on TiO2 films is caused by the unidentate and bidentate linkage. Based on the overall conversion efficiency (eta), fill factor (FF), open-circuit voltage (V(oc)) and short-circuit current (/sc) from the I-V curves measured, it was observed that the photoelectric performance is strongly dependent on the dispersion properties of the nanoporous TiO2 replicas from mesoporous silica templates.

  2. Synthesis of nanocrystalline TiO2 nanorods via hydrothermal method: An efficient photoanode material for dye sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Govindaraj, R.; Santhosh, N.; Senthil Pandian, M.; Ramasamy, P.

    2017-06-01

    Nanocrystalline TiO2 nanorods (NRs) were successfully grown via hydrothermal process. The powder X-ray diffraction (PXRD) pattern shows larger fraction of anatase phase with good crystallinity. Surface morphology of the grown NRs and its dimensions were identified with high resolution transmission electron microscopy (HRTEM) analysis. The crystalline nature of the NRs was also identified with bright spots obtained from selected area electron diffraction (SAED) analysis. The specific surface area and average pore width of the material are 34.84 m2/g and 3.1 nm respectively. Based on the surface morphology, crystalline and mesoporous properties of the NRs, nanocrystalline dye sensitized solar cells (DSSCs) were made and their performances were compared with commercially available Aeroxide P25 nanoparticles. The performance of the NRs shows high short circuit current density (Jsc=15.45 mA/cm2) and high conversion efficiency of 6.5% in DSSCs. From the electrochemical impedance measurement, lower charge transfer resistance (Rct) has been observed for NRs based DSSC device in the interfaces.

  3. Photogeneration and transport of charge carriers in hybrid materials of conjugated polymers and dye-sensitized TiO2

    NASA Astrophysics Data System (ADS)

    Däubler, T. K.; Glowacki, I.; Scherf, U.; Ulanski, J.; Hörhold, H.-H.; Neher, D.

    1999-12-01

    Steady state photoconductivity and current-voltage (I-V) experiments are performed on solid films of organic/inorganic composites of dye-sensitized TiO2 in combination with poly(N-vinylcarbazole) (PVK), a ladder-type PPP and a soluble PPV derivative. The I-V characteristics of the composites in the dark are explained by the formation of percolation networks of nanoparticles between the electrodes. Photoaction spectra of the devices prove that the photogeneration of charge carriers is significantly enhanced and spectrally broadened only if electron transfer from the polymer to the dye is possible. Increasing the concentration of the nanoparticles in the hybrid materials changes the spectral shape of the photoresponse. For high TiO2 contents signatures due to the absorption of the Ruthenium dye can be observed. The different electronic properties of anatase/brookite TiO2 and rutile TiO2 have only minor effects on the generation of charge carriers and on the shape of the photoaction spectra. Indeed, photocurrents are more related to the Brunauer—Emmett-Teller surface area of the nanoparticles and thus, to the amount of dye adsorbed. Charge collection efficiencies exceeding 100%, observed for both bias directions, can be explained by photoconductivity gain. It is proposed that recombination is reduced by transport of the oppositely charged carriers in two different phases.

  4. Reduced graphene oxide/macrocyclic iron complex hybrid materials as counter electrodes for dye-sensitized solar cells.

    PubMed

    Tsai, Chih-Hung; Huang, Wei-Chih; Wang, Wun-Shiuan; Shih, Chun-Jyun; Chi, Wen-Feng; Hu, Yu-Chung; Yu, Yuan-Hsiang

    2017-06-01

    A novel series of reduced graphene oxide (RGO)/macrocyclic iron (Fe) complex hybrid materials were synthesized and then used in the production of counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). The electrode properties of various CEs were comprehensively analyzed using scanning electron microscopy, transmission electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, energy dispersive spectroscopy, Raman spectroscopy, X-ray diffraction, and cyclic voltammetry analyses. DSSCs, based on various CEs, were characterized using current density-voltage, incident monochromatic photon-to-current conversion efficiency, and electrochemical impedance spectroscopy measurements. DSSCs fabricated using the RGO/macrocyclic Fe nanocomposite CEs yielded an efficiency of 6.75%. The RGO/Fe CEs exhibited efficient electrocatalytic capability because catalytic Fe particles were uniformly distributed on the surface of RGO. The results indicated that a DSSC with a RGO/Fe CE can exhibit an efficiency comparable to that of a platinum (Pt) CE DSSC and can therefore replace conventional Pt CE DSSCs to lower the cost of solar cells.

  5. Weight Reduction of Isotropic Cylinders Using Equivalent Compound Cylinders

    DTIC Science & Technology

    1992-02-01

    in weight by replacing material from its outer diameter with a lightweight stiff composite material, such that the resulting compound cylinder has a...14 IV. REPLACEMENT MATERIALS FOR ALUMINUM ...................................14 LIST OF ILLUSTRATIONS 1. %WR versus R for equivalent...radius ’bo’ can be made lighter by replacing material at its outer diameter with a lightweight stiff composite material such that the resulting

  6. Tissue Engineered Human Skin Equivalents

    PubMed Central

    Zhang, Zheng; Michniak-Kohn, Bozena B.

    2012-01-01

    Human skin not only serves as an important barrier against the penetration of exogenous substances into the body, but also provides a potential avenue for the transport of functional active drugs/reagents/ingredients into the skin (topical delivery) and/or the body (transdermal delivery). In the past three decades, research and development in human skin equivalents have advanced in parallel with those in tissue engineering and regenerative medicine. The human skin equivalents are used commercially as clinical skin substitutes and as models for permeation and toxicity screening. Several academic laboratories have developed their own human skin equivalent models and applied these models for studying skin permeation, corrosivity and irritation, compound toxicity, biochemistry, metabolism and cellular pharmacology. Various aspects of the state of the art of human skin equivalents are reviewed and discussed. PMID:24300178

  7. Optical metrics and projective equivalence

    SciTech Connect

    Casey, Stephen; Dunajski, Maciej; Gibbons, Gary; Warnick, Claude

    2011-04-15

    Trajectories of light rays in a static spacetime are described by unparametrized geodesics of the Riemannian optical metric associated with the Lorentzian spacetime metric. We investigate the uniqueness of this structure and demonstrate that two different observers, moving relative to one another, who both see the Universe as static may determine the geometry of the light rays differently. More specifically, we classify Lorentzian metrics admitting more than one hyper-surface orthogonal timelike Killing vector and analyze the projective equivalence of the resulting optical metrics. These metrics are shown to be projectively equivalent up to diffeomorphism if the static Killing vectors generate a group SL(2,R), but not projectively equivalent in general. We also consider the cosmological C metrics in Einstein-Maxwell theory and demonstrate that optical metrics corresponding to different values of the cosmological constant are projectively equivalent.

  8. Research on the interaction of hydrogen-bond acidic polymer sensitive sensor materials with chemical warfare agents simulants by inverse gas chromatography.

    PubMed

    Yang, Liu; Han, Qiang; Cao, Shuya; Huang, Feng; Qin, Molin; Guo, Chenghai; Ding, Mingyu

    2015-06-02

    Hydrogen-bond acidic polymers are important high affinity materials sensitive to organophosphates in the chemical warfare agent sensor detection process. Interactions between the sensor sensitive materials and chemical warfare agent simulants were studied by inverse gas chromatography. Hydrogen bonded acidic polymers, i.e., BSP3, were prepared for micro-packed columns to examine the interaction. DMMP (a nerve gas simulant) and 2-CEES (a blister agent simulant) were used as probes. Chemical and physical parameters such as heats of absorption and Henry constants of the polymers to DMMP and 2-CEES were determined by inverse gas chromatography. Details concerning absorption performance are also discussed in this paper.

  9. Research on the Interaction of Hydrogen-Bond Acidic Polymer Sensitive Sensor Materials with Chemical Warfare Agents Simulants by Inverse Gas Chromatography

    PubMed Central

    Yang, Liu; Han, Qiang; Cao, Shuya; Huang, Feng; Qin, Molin; Guo, Chenghai; Ding, Mingyu

    2015-01-01

    Hydrogen-bond acidic polymers are important high affinity materials sensitive to organophosphates in the chemical warfare agent sensor detection process. Interactions between the sensor sensitive materials and chemical warfare agent simulants were studied by inverse gas chromatography. Hydrogen bonded acidic polymers, i.e., BSP3, were prepared for micro-packed columns to examine the interaction. DMMP (a nerve gas simulant) and 2-CEES (a blister agent simulant) were used as probes. Chemical and physical parameters such as heats of absorption and Henry constants of the polymers to DMMP and 2-CEES were determined by inverse gas chromatography. Details concerning absorption performance are also discussed in this paper. PMID:26043177

  10. High sensitivity radiographic NDT using fluorescent screens

    SciTech Connect

    Trapp, L.F.; Aman, J.K.

    1993-12-31

    Fluorescent Screen exposure previously reserved for thick sections, to shorten long exposures, may now be used for routine radiography. Changes in four areas make this possible: screen technology; specifications; imaging materials not previously available; and technique adjustment. This presentation covers these four areas, the use of fluorescent screens and image quality experimentation that show equivalent sensitivity with conventional techniques. The exposures were shorter and more productive.

  11. Materialism.

    PubMed

    Melnyk, Andrew

    2012-05-01

    Materialism is nearly universally assumed by cognitive scientists. Intuitively, materialism says that a person's mental states are nothing over and above his or her material states, while dualism denies this. Philosophers have introduced concepts (e.g., realization and supervenience) to assist in formulating the theses of materialism and dualism with more precision, and distinguished among importantly different versions of each view (e.g., eliminative materialism, substance dualism, and emergentism). They have also clarified the logic of arguments that use empirical findings to support materialism. Finally, they have devised various objections to materialism, objections that therefore serve also as arguments for dualism. These objections typically center around two features of mental states that materialism has had trouble in accommodating. The first feature is intentionality, the property of representing, or being about, objects, properties, and states of affairs external to the mental states. The second feature is phenomenal consciousness, the property possessed by many mental states of there being something it is like for the subject of the mental state to be in that mental state. WIREs Cogn Sci 2012, 3:281-292. doi: 10.1002/wcs.1174 For further resources related to this article, please visit the WIREs website.

  12. Equivalent damage: A critical assessment

    NASA Technical Reports Server (NTRS)

    Laflen, J. R.; Cook, T. S.

    1982-01-01

    Concepts in equivalent damage were evaluated to determine their applicability to the life prediction of hot path components of aircraft gas turbine engines. Equivalent damage was defined as being those effects which influence the crack initiation life-time beyond the damage that is measured in uniaxial, fully-reversed sinusoidal and isothermal experiments at low homologous temperatures. Three areas of equivalent damage were examined: mean stress, cumulative damage, and multiaxiality. For each area, a literature survey was conducted to aid in selecting the most appropriate theories. Where possible, data correlations were also used in the evaluation process. A set of criteria was developed for ranking the theories in each equivalent damage regime. These criteria considered aspects of engine utilization as well as the theoretical basis and correlative ability of each theory. In addition, consideration was given to the complex nature of the loading cycle at fatigue critical locations of hot path components; this loading includes non-proportional multiaxial stressing, combined temperature and strain fluctuations, and general creep-fatigue interactions. Through applications of selected equivalent damage theories to some suitable data sets it was found that there is insufficient data to allow specific recommendations of preferred theories for general applications. A series of experiments and areas of further investigations were identified.

  13. SU-E-T-353: Verification of Water Equivalent Thickness (WET) and Water Equivalent Spreadness (WES) of Proton Beam

    SciTech Connect

    Demez, N; Lee, T; Keppel, Cynthia

    2011-06-01

    Purpose: To verify calculated water equivalent thickness (WET) and water equivalent spreadness (WES) in various tissue equivalent media for proton therapy Methods: Water equivalent thicknesses (WET) of tissue equivalent materials have been calculated using the Bragg-Kleeman rule. Lateral spreadness and fluence reduction of proton beams both in those media were calculated using proton loss model (PLM) algorithm. In addition, we calculated lateral spreadness ratios with respect to that in water at the same WET depth and so the WES was defined. The WETs of those media for different proton beam energies were measured using MLIC (Multi-Layered Ionization Chamber). Also, fluence and field sizes in those materials of various thicknesses were measured with ionization chambers and films Results: Calculated WETs are in agreement with measured WETs within 0.5%. We found that water equivalent spreadness (WES) is constant and the fluence and field size measurements verify that fluence can be estimated using the concept of WES. Conclusions: Calculation of WET based on the Bragg-Kleeman rule as well as the constant WES of proton beams for tissue equivalent phantoms can be used to predict fluence and field sizes at the depths of interest both in tissue equivalent media accurately for clinically available protonenergies.

  14. Design rules for the optimization of the sensitivity of open-ended coaxial microwave sensors for monitoring changes in dielectric materials

    NASA Astrophysics Data System (ADS)

    García-Baños, Beatriz; Catalá-Civera, José M.; Canós, Antoni J.; Peñaranda-Foix, Felipe

    2005-05-01

    Open-ended coaxial probes are widely used for non-destructive measurement of dielectric properties of materials, and also as microwave sensors for industrial processes and quality control applications. The main design parameters of these sensors are the coaxial radii and working frequency. In this paper, the influence of these variables on the final sensitivity of the coaxial sensor when monitoring dielectric materials is analysed, and a novel expression for this parameter selection is proposed. Moreover, a method to select the optimum parameters of experimental configurations is provided. Measurements demonstrate that high discrimination can be achieved with this method when monitoring changes in the dielectric properties of materials.

  15. Adulteration screening of botanical materials by a sensitive and model-free approach using infrared spectroscopic imaging and two-dimensional correlation infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Chen, Jian-bo; Zhou, Qun; Sun, Su-qin

    2016-11-01

    Infrared (IR) spectroscopy is often used as a simple, fast, and green method for the adulteration screening of botanical materials for foods and herbs. However, the overlapping of absorption signals of various substances significantly decrease the sensitivity and specificity of IR spectroscopy in the detection of adulterated samples. In this research, a model-free approach is proposed for the sensitive and non-targeted screening of botanical materials adulterated by adding other plant materials. First, the spectra of the entities in the test sample are collected by near-infrared spectroscopic imaging and clustered by unsupervised pattern recognition methods. The sample may be adulterated if there are two or more clusters of the entities. Next, the entities of different clusters are characterized by mid-infrared spectroscopy to interpret the chemical compositions to determine the clustering is caused whether by adulteration or other reasons. Second derivative spectroscopy and two-dimensional correlation spectroscopy are often needed to resolve the overlapped bands mathematically or experimentally to find the characteristic signals to identify the authentic and adulterant entities. The feasibility of this approach was proved by the simulated adulterated sample of saffron. In conclusion, botanical materials adulterated by adding other plant materials can be detected by a simple, fast, sensitive, and green screening approach using IR spectroscopic imaging, two-dimensional correlation spectroscopy, and necessary chemometrics techniques.

  16. Dye-Sensitized Solar Cells Based on the Principles and Materials of Photosynthesis: Mechanisms of Suppression and Enhancement of Photocurrent and Conversion Efficiency

    PubMed Central

    Koyama, Yasushi; Miki, Takeshi; Wang, Xiao-Feng; Nagae, Hiroyoshi

    2009-01-01

    Attempts have been made to develop dye-sensitized solar cells based on the principles and materials of photosynthesis: We first tested photosynthetic pigments, carotenoids (Cars), chlorophylls (Chls) and their derivatives, to find sensitizers showing reasonable performance (photocurrent and conversion efficiency). We then tried to introduce the principles of photosynthesis, including electron transfer and energy transfer from Car to Phe a. Also, we tried co-sensitization using the pheophorbide (Phe) a and Chl c2 pair which further enhanced the performance of the component sensitizers as follows: Jsc = 9.0 + 13.8 → 14.0 mA cm−2 and η = 3.4 + 4.6 → 5.4%. PMID:20087456

  17. Dye-sensitized solar cells based on the principles and materials of photosynthesis: mechanisms of suppression and enhancement of photocurrent and conversion efficiency.

    PubMed

    Koyama, Yasushi; Miki, Takeshi; Wang, Xiao-Feng; Nagae, Hiroyoshi

    2009-10-27

    Attempts have been made to develop dye-sensitized solar cells based on the principles and materials of photosynthesis: We first tested photosynthetic pigments, carotenoids (Cars), chlorophylls (Chls) and their derivatives, to find sensitizers showing reasonable performance (photocurrent and conversion efficiency). We then tried to introduce the principles of photosynthesis, including electron transfer and energy transfer from Car to Phe a. Also, we tried co-sensitization using the pheophorbide (Phe) a and Chl c(2) pair which further enhanced the performance of the component sensitizers as follows: J(sc) = 9.0 + 13.8 --> 14.0 mA cm(-2) and eta = 3.4 + 4.6 --> 5.4%.

  18. Reflector modelling of small high leakage cores making use of multi-group nodal equivalence theory

    SciTech Connect

    Theron, S. A.; Reitsma, F.

    2012-07-01

    This research focuses on modelling reflectors in typical material testing reactors (MTRs). Equivalence theory is used to homogenise and collapse detailed transport solutions to generate equivalent nodal parameters and albedo boundary conditions for reflectors, for subsequent use in full core nodal diffusion codes. This approach to reflector modelling has been shown to be accurate for two-group large commercial light water reactor (LWR) analysis, but has not been investigated for MTRs. MTRs are smaller, with much larger leakage, environment sensitivity and multi-group spectrum dependencies than LWRs. This study aims to determine if this approach to reflector modelling is an accurate and plausible homogenisation technique for the modelling of small MTR cores. The successful implementation will result in simplified core models, better accuracy and improved efficiency of computer simulations. Codes used in this study include SCALE 6.1, OSCAR-4 and EQUIVA (the last two codes are developed and used at Necsa). The results show a five times reduction in calculational time for the proposed reduced reactor model compared to the traditional explicit model. The calculated equivalent parameters however show some sensitivity to the environment used to generate them. Differences in the results compared to the current explicit model, require more careful investigation including comparisons with a reference result, before its implementation can be recommended. (authors)

  19. TNT equivalency of M10 propellant

    NASA Technical Reports Server (NTRS)

    Mcintyre, F. L.; Price, P.

    1978-01-01

    Peak, side-on blast overpressure and scaled, positive impulse have been measured for M10 single-perforated propellant, web size 0.018 inches, using configurations that simulate the handling of bulk material during processing and shipment. Quantities of 11.34, 22.7, 45.4, and 65.8 kg were tested in orthorhombic shipping containers and fiberboard boxes. High explosive equivalency values for each test series were obtained as a function of scaled distance by comparison to known pressure, arrival time and impulse characteristics for hemispherical TNT surface bursts. The equivalencies were found to depend significantly on scaled distance, with higher values of 150-100 percent (pressure) and 350-125 percent (positive impulse) for the extremes within the range from 1.19 to 3.57 m/cube root of kg. Equivalencies as low as 60-140 percent (pressure) and 30-75 percent (positive impulse) were obtained in the range of 7.14 to 15.8 m/cube root of kg. Within experimental error, both peak pressure and positive impulse scaled as a function of charge weight for all quantities tested in the orthorhombic configuration.

  20. Multiple Functions in Equivalence Classes

    ERIC Educational Resources Information Center

    McVeigh, Brian; Keenan, Mickey

    2009-01-01

    Four experiments examined the effects of training a "drawing" response to each of three stimuli in a 5-member equivalence class. In Experiment 1 the stimuli were an arbitrary word, a shape, or a mathematical symbol. Subjects then were trained to draw a separate component of a stickman at each of the 3 stimuli. Subsequent tests for function…

  1. The structure of equivalence classes

    PubMed Central

    Fields, Lanny; Verhave, Thom

    1987-01-01

    The structure of equivalence classes can be completely described by four parameters: class size, number of nodes, the distribution of “singles” among nodes, and directionality of training. Class size refers to the number of stimuli in a class. Nodes are stimuli linked by training to at least two other stimuli. Singles are stimuli linked by training to only one other stimulus. The distribution of singles refers to the number of singles linked by training to each node. Directionality of training refers to the use of stimuli as samples and as comparison stimuli in training. These four parameters define the different ways in which the stimuli in a class can be organized, and thus provide a basis for systematically characterizing the properties of stimuli in a given equivalence class. The four parameters can also be used to account for the development of individual differences that are commonly characterized in terms of “understanding” and connotative meaning. Methods are described for generating all possible combinations of parameter values, and a formula is introduced which specifies all of the parameter values for an equivalence class. Its utility for interrelating experimental procedures is demonstrated by analyzing a number of representative experiments that have addressed equivalence-class formation. PMID:16812494

  2. Adult Nonconservation of Numerical Equivalence.

    ERIC Educational Resources Information Center

    Murray, Frank B.; Armstrong, Sharon L.

    A conservation problem of numerical equivalence which 80% of adults reliably fail and 40% of third graders pass was developed, and responses of 188 subjects (Grades 2, 3, 5, 7, 9, 11 and college) to it and related number conservation and probability problems indicated that the differences in nonconservation were rooted in subjects' different…

  3. USEPA PATHOGEN EQUIVALENCY COMMITTEE RETREAT

    EPA Science Inventory

    The Pathogen Equivalency Committee held its retreat from September 20-21, 2005 at Hueston Woods State Park in College Corner, Ohio. This presentation will update the PEC’s membership on emerging pathogens, analytical methods, disinfection techniques, risk analysis, preparat...

  4. Expanding the Interaction Equivalency Theorem

    ERIC Educational Resources Information Center

    Rodriguez, Brenda Cecilia Padilla; Armellini, Alejandro

    2015-01-01

    Although interaction is recognised as a key element for learning, its incorporation in online courses can be challenging. The interaction equivalency theorem provides guidelines: Meaningful learning can be supported as long as one of three types of interactions (learner-content, learner-teacher and learner-learner) is present at a high level. This…

  5. Children's Equivalence Judgments: Crossmapping Effects

    ERIC Educational Resources Information Center

    Mix, Kelly S.

    2008-01-01

    Preschoolers made numerical comparisons between sets with varying degrees of shared surface similarity. When surface similarity was pitted against numerical equivalence (i.e., crossmapping), children made fewer number matches than when surface similarity was neutral (i.e, all sets contained the same objects). Only children who understood the…

  6. Equivalent Linear Logistic Test Models.

    ERIC Educational Resources Information Center

    Bechger, Timo M.; Verstralen, Huub H. F. M.; Verhelst, Norma D.

    2002-01-01

    Discusses the Linear Logistic Test Model (LLTM) and demonstrates that there are many equivalent ways to specify a model. Analyzed a real data set (300 responses to 5 analogies) using a Lagrange multiplier test for the specification of the model, and demonstrated that there may be many ways to change the specification of an LLTM and achieve the…

  7. USEPA PATHOGEN EQUIVALENCY COMMITTEE RETREAT

    EPA Science Inventory

    The Pathogen Equivalency Committee held its retreat from September 20-21, 2005 at Hueston Woods State Park in College Corner, Ohio. This presentation will update the PEC’s membership on emerging pathogens, analytical methods, disinfection techniques, risk analysis, preparat...

  8. Acquired Equivalence Changes Stimulus Representations

    ERIC Educational Resources Information Center

    Meeter, M.; Shohamy, D.; Myers, C. E.

    2009-01-01

    Acquired equivalence is a paradigm in which generalization is increased between two superficially dissimilar stimuli (or antecedents) that have previously been associated with similar outcomes (or consequents). Several possible mechanisms have been proposed, including changes in stimulus representations, either in the form of added associations or…

  9. Representational Implications for Understanding Equivalence

    ERIC Educational Resources Information Center

    Capraro, Mary Margaret; Ding, Meixia; Matteson, Shirley; Capraro, Robert M.; Li, Xiaobao

    2007-01-01

    Teachers and researchers have long recognized that students tend to misunderstand the equal sign as an operator; that is, a signal for "doing something" rather than a relational symbol of equivalence or quantity sameness. Students' equal sign misconception has been researched for more than thirty years (Weaver, 1971, 1973) with little…

  10. Equivalence theorem in effective theories

    NASA Astrophysics Data System (ADS)

    Chicherin, D.; Gorbenko, V.; Vereshagin, V.

    2011-11-01

    The famous equivalence theorem is reexamined in order to make it applicable to the case of effective theories. We slightly modify the formulation of this theorem and prove it based on the notion of the generating functional for Green functions. This allows one to trace (directly in terms of graphs) the mutual cancellation of different groups of contributions.

  11. Performances of some low-cost counter electrode materials in CdS and CdSe quantum dot-sensitized solar cells

    PubMed Central

    2014-01-01

    Different counter electrode (CE) materials based on carbon and Cu2S were prepared for the application in CdS and CdSe quantum dot-sensitized solar cells (QDSSCs). The CEs were prepared using low-cost and facile methods. Platinum was used as the reference CE material to compare the performances of the other materials. While carbon-based materials produced the best solar cell performance in CdS QDSSCs, platinum and Cu2S were superior in CdSe QDSSCs. Different CE materials have different performance in the two types of QDSSCs employed due to the different type of sensitizers and composition of polysulfide electrolytes used. The poor performance of QDSSCs with some CE materials is largely due to the lower photocurrent density and open-circuit voltage. The electrochemical impedance spectroscopy performed on the cells showed that the poor-performing QDSSCs had higher charge-transfer resistances and CPE values at their CE/electrolyte interfaces. PMID:24512605

  12. Applications of Metal Oxide Materials in Dye Sensitized Photoelectrosynthesis Cells for Making Solar Fuels: Let the Molecules do the Work

    SciTech Connect

    Alibabaei, Leila; Luo, Hanlin; House, Ralph L.; Hoertz, Paul G.; Lopez, Rene; Meyer, Thomas J.

    2013-01-01

    Solar fuels hold great promise as a permanent, environmentally friendly, long-term renewable energy source, that would be readily available across the globe. In this account, an approach to solar fuels is described based on Dye Sensitized Photoelectrosynthesis Cells (DSPEC) that mimic the configuration used in Dye Sensitized Solar Cells (DSSC), but with the goal of producing oxygen and a high energy solar fuel in the separate compartments of a photoelectrochemical cell rather than a photopotential and photocurrent.

  13. Defense Transportation: DOD Needs to Improve the Evaluation of Safety and Performance Information for Carriers Transporting Security-Sensitive Materials

    DTIC Science & Technology

    2015-12-01

    violations related to a driver’s use of controlled substances while transporting hazardous materials . Absent an approach to review available violation...BASIC), Including Those Incurred While Transporting Hazardous Materials (November 2012-October 2014) 26 Figure 8: TPS Carrier Incident Data in the...Administration HAZMAT Hazardous Materials MFTURP-1 Military Freight Traffic Unified Rules Publication-1 TRANSCOM U.S. Transportation Command SRC

  14. Test of the Equivalence Principle in an Einstein Elevator

    NASA Technical Reports Server (NTRS)

    Shapiro, Irwin I.; Glashow, S.; Lorenzini, E. C.; Cosmo, M. L.; Cheimets, P.; Finkelstein, N.; Schneps, M.

    2004-01-01

    The scientific goal of the experiment is to test the equality of gravitational and inertial mass (i.e., to test the Principle of Equivalence) by measuring the independence of the rate of fall of bodies from the composition of the falling body. The measurement is accomplished by measuring the relative displacement (or equivalently acceleration) of two falling bodies of different materials which are the proof masses of a differential accelerometer. The goal of the experiment is to measure the Eoetvoes ratio sigma g/g (differential acceleration/common acceleration) with an accuracy goal of several parts in 10(exp 15). The estimated accuracy is about two orders of magnitude better than the present state of the art. The main goal of the study to be carried out under this grant is part of the flight definition of the experiment and laboratory testing of key components. The project involves an international cooperation in which the responsibility of the US side is the flight definition of the experimental facility while the responsibility of the non-US partners is the flight definition and laboratory prototyping of the differential acceleration detector.In summary, the experiment to be designed is for taking differential acceleration measurements with a high-sensitivity detector (the sensor) during free fall conditions lasting up to 30 s in a disturbance-free acceleration environment. The experiment strategy consists in letting the sensor free fall inside a few meters long (in the vertical direction) evacuated capsule that is falling simultaneously in the rarefied atmosphere after release from a helium balloon flying at a stratospheric altitude.

  15. Effect of primary-zone equivalence ratio on pollutant formation

    NASA Technical Reports Server (NTRS)

    Claus, R. W.

    1979-01-01

    Test were conducted to determine the effect of primary-zone equivalence ratio on the formation of smoke and other gaseous pollutants in an experimental can combustor. Several fuel injection techniques were examined at primary-zone equivalence ratios from 0.8 to 2.0. The main emphasis was on reducing fuel-rich-combustion smoke levels. Two of the four fuel injection configurations studied produced smoke levels below a smoke number of 20 at a primary-zone equivalence ratio of about 1.7. As the fuel mixing and atomization were recorded at primary-zone equivalence ratios as high as 2.0. The gaseous emissions of unburned hydrocarbons, carbon monoxide, and oxides of nitrogen were quite sensitive to the fuel injection configuration as well as to the primary-zone equilvalence ratio.

  16. 14 CFR 1213.107 - Preventing unauthorized release of sensitive but unclassified (SBU) information/material to the...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... but unclassified (SBU) information/material to the news media. 1213.107 Section 1213.107 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION RELEASE OF INFORMATION TO NEWS AND INFORMATION.../material to the news media. (a) All NASA SBU information requires accountability and approval for release...

  17. Ronchi test with equivalent wavelength.

    PubMed

    García-Arellano, Anmi; Granados-Agustín, Fermín; Campos-García, Manuel; Cornejo-Rodríguez, Alejandro

    2012-05-20

    In this work we present an experimental proposal to evaluate optical surfaces with high slopes or with infrared wavelengths based on the Ronchi test as well as on the concept of equivalent wavelength. A spatial modulator is used in the implementation of the Ronchi test, and a white LED with different color filters is employed in order to generate different wavelengths. Two Ronchigrams with incoherent light, each one for a different color, are registered and computationally processed, thus generating a third one with an equivalent wavelength. The results obtained show that it is possible to generate patterns with traditional rulings and substructured sequences of Katyl. Additionally, we discuss some of the limitations of employing different rulings. Finally, we found that appropriate image enhancing algorithms allow us to improve the visibility of the resulting fringes and thus obtain a better analysis.

  18. Equivalence theorem of uncertainty relations

    NASA Astrophysics Data System (ADS)

    Li, Jun-Li; Qiao, Cong-Feng

    2017-01-01

    We present an equivalence theorem to unify the two classes of uncertainty relations, i.e. the variance-based ones and the entropic forms, showing that the entropy of an operator in a quantum system can be built from the variances of a set of commutative operators. This means that an uncertainty relation in the language of entropy may be mapped onto a variance-based one, and vice versa. Employing the equivalence theorem, alternative formulations of entropic uncertainty relations are obtained for the qubit system that are stronger than the existing ones in the literature, and variance-based uncertainty relations for spin systems are reached from the corresponding entropic uncertainty relations.

  19. Equivalent circuit for birdcage resonators.

    PubMed

    Harpen, M D

    1993-02-01

    We present an equivalent circuit analysis for both low pass and high pass birdcage resonators loaded with lossy samples. In a generalization of the method of Hoult and Lauterbur (J. Magn. Reson. 34, 425 (1979)), we also derive circuit component values by application of the laws of electrodynamics. Measured resonance spectra, quality factors, and feed point impedances in a test resonator are shown to be in agreement with those predicted by the proposed model.

  20. Equivalence of quadratic performance criteria.

    NASA Technical Reports Server (NTRS)

    Martin, C.

    1973-01-01

    Necessary and sufficient conditions are derived in terms of system parameters and quadratic weighting matrices for two quadratic cost functionals that are defined to be equivalent if they generate the same optimal control law. The derived conditions lie between the conditions of Tanaka and Asai (1971) and those of Kreindler and Hedrick (1970). Sufficient conditions for a vector valued function to attain an infimum are stated.

  1. TNT Equivalency of Bulk Nitrocellulose

    DTIC Science & Technology

    1981-03-01

    9TIN ’IN AD-E400 576 CONTRACTOR REPORT ARLCD-CR-81007 TNT EQUIVALENCY OF BULK NITROCELLULOSE F. L. MCINTYRE COMPUTER SCIENCES CORPORATION NSTL...September 1978 6. PERFORMING ORG. REPORT NUMBER 7. AUTHOR(S) 8. CONTRACT OR GRANT NUMBER(e) F. L. Mc~ntyre, Computer Sciences Corporation P. Price...PROJECT. TASK Computer Sciences Corporation AREA & WORK UNIT NUMBERS NSTL Station, MS 39529 MMT-5784285 II. CONTROLLING OFFICE NAME AND ADDRESS 12

  2. Miniature LIMS system designed for sensitive in situ measurements of organic deposits in materials on solar system objects

    NASA Astrophysics Data System (ADS)

    Riedo, Andreas; Moreno-García, Pavel; Grimaudo, Valentine; Brigitte Neuland, Maike; Tulej, Marek; Broekmann, Peter; Wurz, Peter

    2014-05-01

    In situ investigation of chemical composition is of considerable interest for application in planetary missions. The possibility of bio-relevant organic chemistry on the surfaces of comets and primitive asteroids is one of the most intriguing problems of the current astrobiology. Rock-water interface existed in early small solar body history, in addition to extensive mineralogical modifications of the surface could have initiated also a rich organic and bio-organic chemistry [1]. Current space instrumentation designed for molecular detection use thermal evaporation source combined with gas chromatography (GC) and mass spectrometry [2]. Hence, it is capable of collecting data of the volatile fraction of the investigated sample. Laser desorption mass spectrometry (LD-MS) is another method for molecule detection capable of vaporisation and ionisation of molecules present on a solid substrate surface, e.g. a rock. A miniature laser ablation ionisation reflectron-type time-of-flight mass analyser (LMS) developed by our group for in situ measurements of the elemental, isotopic composition can be used also for sensitive analyses of chemical compounds present on solid surfaces with high spatial resolution [3-6]. Comparing to laser ablation laser desorption analyses are conducted at laser irradiance reduced by approximately 103-104 times. In laser ablation mode, the LMS system offers high dynamic range of at least eight orders of magnitude and allows for the detection in the ppb range for metallic- and non-metallic elements. Instrument mass resolution m/Δm is about 800 at the 56Fe mass peak when the instrument is used in ablation mode. The mass resolution is increased to m/Δm >1000 when desorption studies are conducted (at ~600 m/q). We will demonstrate the instrument performance conducting molecular desorption studies of different species, e.g. organic, biotic and abiotic. Laser ablation/ionisation studies are conducted in parallel to complement the laser desorption

  3. Equivalent statistics and data interpretation.

    PubMed

    Francis, Gregory

    2017-08-01

    Recent reform efforts in psychological science have led to a plethora of choices for scientists to analyze their data. A scientist making an inference about their data must now decide whether to report a p value, summarize the data with a standardized effect size and its confidence interval, report a Bayes Factor, or use other model comparison methods. To make good choices among these options, it is necessary for researchers to understand the characteristics of the various statistics used by the different analysis frameworks. Toward that end, this paper makes two contributions. First, it shows that for the case of a two-sample t test with known sample sizes, many different summary statistics are mathematically equivalent in the sense that they are based on the very same information in the data set. When the sample sizes are known, the p value provides as much information about a data set as the confidence interval of Cohen's d or a JZS Bayes factor. Second, this equivalence means that different analysis methods differ only in their interpretation of the empirical data. At first glance, it might seem that mathematical equivalence of the statistics suggests that it does not matter much which statistic is reported, but the opposite is true because the appropriateness of a reported statistic is relative to the inference it promotes. Accordingly, scientists should choose an analysis method appropriate for their scientific investigation. A direct comparison of the different inferential frameworks provides some guidance for scientists to make good choices and improve scientific practice.

  4. Some molecular/crystalline factors that affect the sensitivities of energetic materials: molecular surface electrostatic potentials, lattice free space and maximum heat of detonation per unit volume.

    PubMed

    Politzer, Peter; Murray, Jane S

    2015-02-01

    We discuss three molecular/crystalline properties that we believe to be among the factors that influence the impact/shock sensitivities of energetic materials (i.e., their vulnerabilities to unintended detonation due to impact or shock). These properties are (a) the anomalously strong positive electrostatic potentials in the central regions of their molecular surfaces, (b) the free space per molecule in their crystal lattices, and (c) their maximum heats of detonation per unit volume. Overall, sensitivity tends to become greater as these properties increase; however these are general trends, not correlations. Nitramines are exceptions in that their sensitivities show little or no variation with free space in the lattice and heat of detonation per unit volume. We outline some of the events involved in detonation initiation and show how the three properties are related to different ones of these events.

  5. Development of a Highly Sensitive Nested-PCR Procedure Using a Single Closed Tube for Detection of Erwinia amylovora in Asymptomatic Plant Material

    PubMed Central

    Llop, Pablo; Bonaterra, Anna; Peñalver, Javier; López, María M.

    2000-01-01

    A novel method, which involves a nested PCR in a single closed tube, was developed for the sensitive detection of Erwinia amylovora in plant material. The external and internal primer pairs used had different annealing temperatures and directed the amplification of a specific DNA fragment from plasmid pEA29. The procedure involved two consecutive PCRs, the first of which was performed at a higher annealing temperature that allowed amplification only by the external primer pair. Using pure cultures of E. amylovora, the sensitivity of the nested PCR in one tube was similar to that of a standard nested PCR in two tubes. The specificity and sensitivity were greater than those of standard PCR procedures that used a single primer pair. The presence of inhibitors in plant material, very common in E. amylovora hosts, is overcome with this system in combination with a simple DNA extraction protocol because it eliminates many of the inhibitory compounds. In addition, it needs a very small sample volume (1 μl of DNA extracted). With 83 samples of naturally infected material, this method achieved better results than any other PCR technique: standard PCR detected 55% of positive samples, two-tube nested PCR detected 71% of positive samples, and nested PCR in a single closed tube detected 78% of positive samples. When analyzing asymptomatic plant material, the number of positive samples detected by the developed nested PCR was also the highest, compared with the PCR protocols indicated previously (17, 20, and 25% of 251 samples analyzed, respectively). This method is proposed for the detection of endophytic and epiphytic populations of E. amylovora in epidemiological studies and for routine use in quarantine surveys, due to its high sensitivity, specificity, speed, and simplicity. PMID:10788384

  6. Information Leakage from Logically Equivalent Frames

    ERIC Educational Resources Information Center

    Sher, Shlomi; McKenzie, Craig R. M.

    2006-01-01

    Framing effects are said to occur when equivalent frames lead to different choices. However, the equivalence in question has been incompletely conceptualized. In a new normative analysis of framing effects, we complete the conceptualization by introducing the notion of information equivalence. Information equivalence obtains when no…

  7. An electro-optical and electron injection study of benzothiazole-based squaraine dyes as efficient dye-sensitized solar cell materials: a first principles study.

    PubMed

    Al-Fahdan, Najat Saeed; Asiri, Abdullah M; Irfan, Ahmad; Basaif, Salem A; El-Shishtawy, Reda M

    2014-12-01

    Squaraine dyes have attracted significant attention in many areas of daily life from biomedical imaging to semiconducting materials. Moreover, these dyes are used as photoactive materials in the field of solar cells. In the present study, we investigated the structural, electronic, photophysical, and charge transport properties of six benzothiazole-based squaraine dyes (Cis-SQ1-Cis-SQ3 and Trans-SQ1-Trans-SQ3). The effect of electron donating (-OCH3) and electron withdrawing (-COOH) groups was investigated intensively. Ground state geometry and frequency calculations were performed by applying density functional theory (DFT) at B3LYP/6-31G** level of theory. Absorption spectra were computed in chloroform at the time-dependent DFT/B3LYP/6-31G** level of theory. The driving force of electron injection (ΔG (inject)), relative driving force of electron injection (ΔG r (inject)), electronic coupling constants (|VRP|) and light harvesting efficiency (LHE) of all six compounds were calculated and compared with previously studied sensitizers. The ΔG (inject), ΔG r (inject) and |VRP| of all six compounds revealed that these sensitizers would be efficient dye-sensitized solar cell materials. Cis/Trans-SQ3 exhibited superior LHE as compared to other derivatives. The Cis/Trans geometric effect was studied and discussed with regard to electro-optical and charge transport properties.

  8. A novel surface-sensitive X-ray absorption spectroscopic detector to study the thermal decomposition of cathode materials for Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Nonaka, Takamasa; Okuda, Chikaaki; Oka, Hideaki; Nishimura, Yusaku F.; Makimura, Yoshinari; Kondo, Yasuhito; Dohmae, Kazuhiko; Takeuchi, Yoji

    2016-09-01

    A surface-sensitive conversion-electron-yield X-ray absorption fine structure (CEY-XAFS) detector that operates at elevated temperatures is developed to investigate the thermal decomposition of cathode materials for Li-ion batteries. The detector enables measurements with the sample temperature controlled from room temperature up to 450 °C. The detector is applied to the LiNi0.75Co0.15Al0.05Mg0.05O2 cathode material at 0% state of charge (SOC) and 50% SOC to examine the chemical changes that occur during heating in the absence of an electrolyte. The combination of surface-sensitive CEY-XAFS and bulk-sensitive transmission-mode XAFS shows that the reduction of Ni and Co ions begins at the surface of the cathode particles at around 150 °C, and propagates inside the particle upon further heating. These changes with heating are irreversible and are more obvious at 50% SOC than at 0% SOC. The fraction of reduced Ni ions is larger than that of reduced Co ions. These results demonstrate the capability of the developed detector to obtain important information for the safe employment of this cathode material in Li-ion batteries.

  9. Dosimetric verification of the anisotropic analytical algorithm in lung equivalent heterogeneities with and without bone equivalent heterogeneities

    SciTech Connect

    Ono, Kaoru; Endo, Satoru; Tanaka, Kenichi; Hoshi, Masaharu; Hirokawa, Yutaka

    2010-08-15

    Purpose: In this study, the authors evaluated the accuracy of dose calculations performed by the convolution/superposition based anisotropic analytical algorithm (AAA) in lung equivalent heterogeneities with and without bone equivalent heterogeneities. Methods: Calculations of PDDs using the AAA and Monte Carlo simulations (MCNP4C) were compared to ionization chamber measurements with a heterogeneous phantom consisting of lung equivalent and bone equivalent materials. Both 6 and 10 MV photon beams of 4x4 and 10x10 cm{sup 2} field sizes were used for the simulations. Furthermore, changes of energy spectrum with depth for the heterogeneous phantom using MCNP were calculated. Results: The ionization chamber measurements and MCNP calculations in a lung equivalent phantom were in good agreement, having an average deviation of only 0.64{+-}0.45%. For both 6 and 10 MV beams, the average deviation was less than 2% for the 4x4 and 10x10 cm{sup 2} fields in the water-lung equivalent phantom and the 4x4 cm{sup 2} field in the water-lung-bone equivalent phantom. Maximum deviations for the 10x10 cm{sup 2} field in the lung equivalent phantom before and after the bone slab were 5.0% and 4.1%, respectively. The Monte Carlo simulation demonstrated an increase of the low-energy photon component in these regions, more for the 10x10 cm{sup 2} field compared to the 4x4 cm{sup 2} field. Conclusions: The low-energy photon by Monte Carlo simulation component increases sharply in larger fields when there is a significant presence of bone equivalent heterogeneities. This leads to great changes in the build-up and build-down at the interfaces of different density materials. The AAA calculation modeling of the effect is not deemed to be sufficiently accurate.

  10. Singlet oxygen sensitizing materials based on porous silicone: photochemical characterization, effect of dye reloading and application to water disinfection with solar reactors.

    PubMed

    Manjón, Francisco; Santana-Magaña, Montserrat; García-Fresnadillo, David; Orellana, Guillermo

    2010-06-01

    Photogeneration of singlet molecular oxygen ((1)O(2)) is applied to organic synthesis (photooxidations), atmosphere/water treatment (disinfection), antibiofouling materials and in photodynamic therapy of cancer. In this paper, (1)O(2) photosensitizing materials containing the dyes tris(4,4'-diphenyl-2,2'-bipyridine)ruthenium(II) (1, RDB(2+)) or tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II) (2, RDP(2+)), immobilized on porous silicone (abbreviated RDB/pSil and RDP/pSil), have been produced and tested for waterborne Enterococcus faecalis inactivation using a laboratory solar simulator and a compound parabolic collector (CPC)-based solar photoreactor. In order to investigate the feasibility of its reuse, the sunlight-exposed RDP/pSil sensitizing material (RDP/pSil-a) has been reloaded with RDP(2+) (RDP/pSil-r). Surprisingly, results for bacteria inactivation with the reloaded material have demonstrated a 4-fold higher efficiency compared to those of either RDP/pSil-a, unused RDB/pSil and the original RDP/pSil. Surface and bulk photochemical characterization of the new material (RDP/pSil-r) has shown that the bactericidal efficiency enhancement is due to aggregation of the silicone-supported photosensitizer on the surface of the polymer, as evidenced by confocal fluorescence lifetime imaging microscopy (FLIM). Photogenerated (1)O(2) lifetimes in the wet sensitizer-doped silicone have been determined to be ten times longer than in water. These facts, together with the water rheology in the solar reactor and the interfacial production of the biocidal species, account for the more effective disinfection observed with the reloaded photosensitizing material. These results extend and improve the operational lifetime of photocatalytic materials for point-of-use (1)O(2)-mediated solar water disinfection.

  11. Cross Section Sensitivity and Propagated Errors in HZE Exposures

    NASA Technical Reports Server (NTRS)

    Heinbockel, John H.; Wilson, John W.; Blatnig, Steve R.; Qualls, Garry D.; Badavi, Francis F.; Cucinotta, Francis A.

    2005-01-01

    It has long been recognized that galactic cosmic rays are of such high energy that they tend to pass through available shielding materials resulting in exposure of astronauts and equipment within space vehicles and habitats. Any protection provided by shielding materials result not so much from stopping such particles but by changing their physical character in interaction with shielding material nuclei forming, hopefully, less dangerous species. Clearly, the fidelity of the nuclear cross-sections is essential to correct specification of shield design and sensitivity to cross-section error is important in guiding experimental validation of cross-section models and database. We examine the Boltzmann transport equation which is used to calculate dose equivalent during solar minimum, with units (cSv/yr), associated with various depths of shielding materials. The dose equivalent is a weighted sum of contributions from neutrons, protons, light ions, medium ions and heavy ions. We investigate the sensitivity of dose equivalent calculations due to errors in nuclear fragmentation cross-sections. We do this error analysis for all possible projectile-fragment combinations (14,365 such combinations) to estimate the sensitivity of the shielding calculations to errors in the nuclear fragmentation cross-sections. Numerical differentiation with respect to the cross-sections will be evaluated in a broad class of materials including polyethylene, aluminum and copper. We will identify the most important cross-sections for further experimental study and evaluate their impact on propagated errors in shielding estimates.

  12. Development of a Portable Sensitive Equipment Decontamination System. Volume 1: Commercial Candidates Materials Evaluation (Chemical Agent Studies)

    DTIC Science & Technology

    2010-05-01

    residual agent from the disk. After a 60 min extraction period, the IPA extract was analyzed for residual HD by Gas Chromatography - Flame Photometric...to the start of a test, the identification number, material type, and dimensions of the test coupon to be used as a substrate in the test were...not conducted on nylon webbing. All of the tests were run at room temperature and ambient relative humidity. The identification number, material

  13. Chlorpromazine equivalent doses for the newer atypical antipsychotics.

    PubMed

    Woods, Scott W

    2003-06-01

    Several clinical and research applications require an estimation of therapeutic dose equivalence across antipsychotic medications. Since the advent of the newer atypical antipsychotics, new dose equivalent estimations have been needed. The reported minimum effective dose was identified for each newer atypical antipsychotic medication and for haloperidol across all available fixed-dose placebo-controlled studies. Reported minimum effective dose equivalence ratios to haloperidol were then converted to chlorpromazine equivalents using the "2 mg of haloperidol equals 100 mg of chlorpromazine" convention. To identify the fixed-dose studies, the following sources were searched until June 2002: MEDLINE, the bibliographies of identified reports, published meta-analyses and reviews, Cochrane reviews, Freedom of Information Act material available from the Food and Drug Administration, and abstracts from several scientific meetings from 1997 to 2002. Doses equivalent to 100 mg/day of chlorpromazine were 2 mg/day for risperidone, 5 mg/day for olanzapine, 75 mg/day for quetiapine, 60 mg/day for ziprasidone, and 7.5 mg/day for aripiprazole. These equivalency estimates may be useful for clinical and research purposes. The source of the dose equivalency estimation is evidence-based and consistent across medication.

  14. Polyoxometalate-modified TiO2 nanotube arrays photoanode materials for enhanced dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Liu, Ran; Sun, Zhixia; Zhang, Yuzhuo; Xu, Lin; Li, Na

    2017-10-01

    In this work, we prepared for the first time the TiO2 nanotube arrays (TNAs) photoanode with polyoxometalate(POMs)-modified TiO2 electron-transport layer for improving the performance of zinc phthalocyanine(ZnPc)-sensitized solar cells. The as-prepared POMs/TNAs/ZnPc composite photoanode exhibited higher photovoltaic performances than the TNAs/ZnPc photoanode, so that the power conversion efficiency of the solar cell device based on the POMs/TNAs/ZnPc photoanode displayed a notable improvement of 45%. These results indicated that the POMs play a key role in reducing charge recombination in phthalocyanine-sensitized solar cells, together with TiO2 nanotube arrays being helpful for electron transport. The mechanism of the performance improvement was demonstrated by the measurements of electrochemical impedance spectra and open-circuit voltage decay curves. Although the resulting performance is still below that of the state-of-the-art dye-sensitized solar cells, this study presents a new insight into improving the power conversion efficiency of phthalocyanine-sensitized solar cells via polyoxometalate-modified TiO2 nanotube arrays photoanode.

  15. Exploring pH-Sensitive Hydrogels Using an Ionic Soft Contact Lens: An Activity Using Common Household Materials

    ERIC Educational Resources Information Center

    Chen, Yueh-Huey; He, Yu-Chi; Yaung, Jing-Fun

    2014-01-01

    Hydrogels of the so-called smart polymers or environment-sensitive polymers are important modern biomaterials. Herein, we describe a hands-on activity to explore the pH-responsive characteristics of hydrogels using a commercially available ionic soft contact lens that is a hydrogel of poly(2-hydroxyethyl methacrylate-"co"-methacrylic…

  16. CuSbS2: a promising semiconductor photo-absorber material for quantum dot sensitized solar cells.

    PubMed

    Liu, Zhifeng; Huang, Jiajun; Han, Jianhuan; Hong, Tiantian; Zhang, Jing; Liu, Zhihua

    2016-06-22

    A facile, low-cost, simple solution-based process for preparing novel promising chalcostibite CuSbS2 sensitized ZnO nanorod arrays, and the application of these as photoanodes of semiconductor quantum dot sensitized inorganic-organic solar cells (QDSSCs) is reported for the first time. ZnO/CuSbS2 nanofilms were designed and prepared through a simple successive ionic layer adsorption and reaction (SILAR) method and heat treatment process by employing ZnO nanorods as reactive templates. Novel efficient QDSSCs based on the ZnO/CuSbS2 nanofilms plus a solid electrolyte of poly(3-hexylthiophene) (P3HT) were formed, and a power conversion efficiency of 1.61% was achieved. The excellent photoelectric performance is attributed to the improved light absorption efficiency, widened light absorption region, ideal band gap value, and high speed electron injection and transportation. The results demonstrate that a novel ternary sensitizer (I-V-VI2) can be synthesized via a low-cost method as described here and has great promising potential as a sensitizer in solar cells.

  17. Exploring pH-Sensitive Hydrogels Using an Ionic Soft Contact Lens: An Activity Using Common Household Materials

    ERIC Educational Resources Information Center

    Chen, Yueh-Huey; He, Yu-Chi; Yaung, Jing-Fun

    2014-01-01

    Hydrogels of the so-called smart polymers or environment-sensitive polymers are important modern biomaterials. Herein, we describe a hands-on activity to explore the pH-responsive characteristics of hydrogels using a commercially available ionic soft contact lens that is a hydrogel of poly(2-hydroxyethyl methacrylate-"co"-methacrylic…

  18. Calorimetric measurement and modelling of the equivalent series of capacitors

    NASA Astrophysics Data System (ADS)

    Seguin, B.; Gosse, J. P.; Ferrieux, J. P.

    1999-12-01

    The equivalent series resistance of polypropylene capacitors has been determined under rated voltage, in the range 1 kHz 1 MHz, between 220 K and 370 K by a calorimetric technique. The original feature of this determination of capacitor losses lies in the use of the isothermal calorimetry and in the measurement of an electrical power and not of a temperature increase. The frequency dependence of the equivalent series resistance, at various temperatures, enables to separate the losses in the conducting material from those in the dielectric and to get their respective variations as a function of frequency and temperature. These variations of the equivalent series resistance with frequency at a given temperature have been reproduced by using an equivalent circuit composed of resistors, inductors and capacitors. This model has been verified for non-sinusoidal waveforms such as those met with in a filtering circuit and is used to evaluate by simulation the losses of the capacitor.

  19. Investigation of electronic band structure and charge transfer mechanism of oxidized three-dimensional graphene as metal-free anodes material for dye sensitized solar cell application

    NASA Astrophysics Data System (ADS)

    Loeblein, Manuela; Bruno, Annalisa; Loh, G. C.; Bolker, Asaf; Saguy, Cecile; Antila, Liisa; Tsang, Siu Hon; Teo, Edwin Hang Tong

    2017-10-01

    Dye-sensitized solar cells (DSSCs) offer an optimal trade-off between conversion-efficiency and low-cost fabrication. However, since all its electrodes need to fulfill stringent work-function requirements, its materials have remained unchanged since DSSC's first report early-90s. Here we describe a new material, oxidized-three-dimensional-graphene (o-3D-C), with a band gap of 0.2 eV and suitable electronic band-structure as alternative metal-free material for DSSCs-anodes. o-3D-C/dye-complex has a strong chemical bonding via carboxylic-group chemisorption with full saturation after 12 sec at capacity of ∼450 mg/g (600x faster and 7x higher than optimized metal surfaces). Furthermore, fluorescence quenching of life-time by 28-35% was measured demonstrating charge-transfer from dye to o-3D-C.

  20. Conformal dynamical equivalence and applications

    NASA Astrophysics Data System (ADS)

    Spyrou, N. K.

    2011-02-01

    The "Conformal Dynamical Equivalence" (CDE) approach is briefly reviewed, and some of its applications, at various astrophysical levels (Sun, Solar System, Stars, Galaxies, Clusters of Galaxies, Universe as a whole), are presented. According to the CDE approach, in both the Newtonian and general-relativistic theories of gravity, the isentropic hydrodynamic flows in the interior of a bounded gravitating perfect-fluid source are dynamically equivalent to geodesic motions in a virtual, fully defined fluid source. Equivalently, the equations of hydrodynamic motion in the former source are functionally similar to those of the geodesic motions in the latter, physically, fully defined source. The CDE approach is followed for the dynamical description of the motions in the fluid source. After an observational introduction, taking into account all the internal physical characteristics of the corresponding perfect-fluid source, and based on the property of the isentropic hydrodynamic flows (quite reasonable for an isolated physical system), we examine a number of issues, namely, (i) the classical Newtonian explanation of the celebrated Pioneer-Anomaly effect in the Solar System, (ii) the possibility of both the attractive gravity and the repulsive gravity in a non-quantum Newtonian framework, (iii) the evaluation of the masses - theoretical, dynamical, and missing - and of the linear dimensions of non-magnetized and magnetized large-scale cosmological structures, (iv) the explanation of the flat-rotation curves of disc galaxies, (v) possible formation mechanisms of winds and jets, and (vi) a brief presentation of a conventional approach - toy model to the dynamics of the Universe, characterized by the dominant collisional dark matter (with its subdominant luminous baryonic "contamination"), correctly interpreting the cosmological observational data without the need of the notions dark energy, cosmological constant, and universal accelerating expansion.

  1. On Vasyliunas's equivalent conductivity formalism

    NASA Technical Reports Server (NTRS)

    Pontius, D. H., Jr.

    1992-01-01

    The Vasyliunas's (1972) equivalent conductivity formalism (ECF) for representing the coupling of the ionosphere and the magnetosphere is discussed, and a new, simpler, derivation is presented of the ECF, in which certain of the underlying assumptions and their implications are made transparent. The derivation presented indicates that the only role of the ions in the ECF is to insure quasi-neutrality. It is shown that the ECF is not as robust as usually assumed and that caution must be used to insure that reasonable results are obtained.

  2. Equivalent intrinsic blur in amblyopia.

    PubMed

    Levi, D M; Klein, S A

    1990-01-01

    We used Gaussian blurred stimuli to explore the effect of blur on three tasks: (i) 2-line resolution; (ii) line detection; and (iii) spatial interval discrimination, in observers with amblyopia due to anisometropia, strabismus, or both. The results of our experiments can be summarized as follows. (i) 2-Line resolution: in normal foveal vision, thresholds for unblurred stimuli are approx. 0.5 min arc in the fovea. When the standard deviation (sigma) of the stimulus blur is less than 0.5 min, it has little effect upon 2-line resolution; however, thresholds are degraded when the stimulus blur, sigma, exceeds 0.5 min. We operationally define this transition point, as the equivalent intrinsic blur, or Bi. When the stimulus blur, sigma, is greater than Bi, then the resolution threshold is approximately equal to sigma. In all of the amblyopic eyes, 2-line resolution thresholds for unblurred stimuli were elevated, and the equivalent intrinsic blur was much larger. When the stimulus blur exceeds the equivalent intrinsic blur, resolution thresholds were similar in amblyopic and nonamblyopic eyes. (ii) Line detection: in both normal and amblyopic eyes, when the stimulus blur, sigma, is less than Bi, then the line detection threshold is approximately inversely proportional to sigma; i.e. (it obeys Ricco's law). When sigma is greater than Bi, the equivalent intrinsic blur, then the detection threshold is approximately a fixed contrast. All of the amblyopic eyes showed markedly elevated thresholds for detecting thin lines, but normal or near normal thresholds for detecting very blurred lines. Consequently, Ricco's diameter is larger in amblyopic than in normal eyes. (iii) Spatial interval discrimination: thresholds are proportional to the separation of the lines (i.e. Weber's law). At the optimal separation, spatial interval discrimination thresholds represent a "hyperacuity" (i.e. they are smaller than the resolution threshold). For unblurred lines, the optimal separation is

  3. Characterization and Gas Sensitivity of Polyaniline/Coral-Like SnO2 Hybrid Material Prepared by In Situ Polymerization.

    PubMed

    Xiang, Tengrui; Lin, Zhidong; Qu, Yang

    2015-06-01

    A PANI/coral-like mesoporous SnO2 hybrid material was fabricated using in situ polymerization method at 0-5 degrees C. The coral-like mesoporous SnO2 was synthesized by controlling the hydrolysis of SnCl4 and subsequent removal of the templates by calcination in air. The obtained PANI/coral-like mesoporous SnO2 hybrid material was characterized by FT-IR, XRD, TEM and SEM. The XRD pattern suggested that PANI did not modify the crystal structure of SnO2, but SnO2 affect the crystallization of PANI to some extents. The SEM and TEM pattern suggested that coral-like mesoporous SnO2 was enwrapped by PANI. The gas-sensing property of PANI/coral-like SnO2 hybrid material was also studied to NH3, trimethylamine (TMA), and SO2 at room temperature. It was found that the sensor based on PANI/coral-like SnO2 hybrid material had higher response and faster response/recovery to NH3, TMA and SO2 than that based on PANI. The sensing mechanism of the hybrid material was also investigated.

  4. Reticulocyte hemoglobin equivalent to detect thalassemia and thalassemic hemoglobin variants.

    PubMed

    Sudmann, Å A; Piehler, A; Urdal, P

    2012-12-01

    Thalassemia and iron deficiency may both result in hypochromic microcytic anemia. Hematological algorithms that differentiate the two are mainly established in adult selected diagnostic groups. We aimed at creating an algorithm applicable in the presence of children, hemoglobin variants, and iron deficiency. Our study material constituted blood samples referred during 1 year for routine diagnostics of hemoglobinopathy. We included 443 samples, of which 37% were from children 3 months or older. We found β-thalassemia trait (n = 100), α-thalassemia (n = 75), combined α-/β-thalassemia (n = 14), hemoglobin variants (n = 42), and no-hemoglobinopathy (n = 207), of whom 107 had a ferritin at or below 20 μg/L. We included reticulocyte hemoglobin equivalent, ferritin, and erythrocyte count in our algorithm. Our algorithm differentiated β-thalassemia trait from no-hemoglobinopathy with a sensitivity of 99% at 83% specificity. It performed better than other published algorithms when applied to all patient samples, while equally or moderately better in the 63% adult samples. Our algorithm also detected the clinically significant α-thalassemias, and most of the combined α-/β-thalassemias and thalassemic hemoglobin variants. Our algorithm efficiently differentiated thalassemia and thalassemic hemoglobin variants from iron deficiency in children and adults. © 2012 Blackwell Publishing Ltd.

  5. Preparation of PbSeO3 as a new material, sensitive to the electromagnetic radiation in UV range

    NASA Astrophysics Data System (ADS)

    Tomaev, V. V.; Smolyaninov, V. D.; Stoyanova, T. V.; Egorov, S. V.

    2016-08-01

    The new technology of the formation of photoresistive structures sensitive in ultraviolet range of electromagnetic spectrum based on lead selenide and lead selenite composite is discussed. Studies of photosensitivity were carried out using a set of LEDs in the visible and ultraviolet spectral range. Obtained structures show considerable sensitivity in ultraviolet and blue range of radiation, meanwhile that in red and yellow region of light turned to be small. The structures were formed by oxidation of PbSe crystals. Diffusion of the oxygen through the surface layer of PbSe was suggested to be a key mechanism of oxidation. Oxidation kinetics were studied by means of roentgen lines chemical shift and roentgen diffraction.

  6. Final Shape of Precision Molded Optics: Part 2 - Validation and Sensitivity to Material Properties and Process Parameters

    DTIC Science & Technology

    2012-06-27

    and a steep meniscus lens. In the current study, after validating the computational approach for both lens types, an extensive sensitivity The views...shape from the mold shape is achieved for both a bi-convex lens and a steep meniscus lens. In the current study, after validating the computational...shape from the mold shape is achieved for both a bi-convex lens and a steep meniscus lens. In the current study, after validating the computational

  7. Therapeutic equivalents in clinical practice.

    PubMed

    Benson, M D

    2001-01-01

    With increasing debate over the rising expenses of health care, a variety of cost-saving measures has been attempted over the years. Use of primary care physicians as "gate keepers," reduction in the length of hospital stays, and pushing women toward vaginal birth after Cesarean section have all been utilized despite on going issues with patient satisfaction and even safety. One remarkable success in stretching health-care dollars that has often been overlooked is the prescription of therapeutic equivalents, or generic drugs. Although available on a limited basis for decades, off-brand manufacture of pharmaceuticals with identical active ingredients as those of the branded drug received a large boost through Congressional legislation in 1984 with the Hatch-Waxman Act. "Fast-track" FDA approval was initiated by Congress to introduce competition into the marketplace for drugs whose patients had expired. While giving close scrutiny to the manufacturing process and requiring the same level of regulatory supervision for factors such as bioavailability and shelf life, the Hatch-Waxman Act removed the burden and expense from generic manufacturers of proving the safety and efficacy all over again of a previously FDA-approved drug. With less than a 20% market share of all prescribed drugs in 1984, the generic drug industry has captured roughly 44% of the market in recent years while accounting for only 8% of expenditures on prescription medication. The prescription of therapeutic equivalents is one method of keeping health care costs down without compromising patient satisfaction or safety.

  8. Reflectance Spectra Diversity of Silica-Rich Materials: Sensitivity to Environment and Implications for Detections on Mars

    NASA Technical Reports Server (NTRS)

    Rice, M. S.; Cloutis, E. A.; Bell, J. F., III; Bish, D. L.; Horgan, B. H.; Mertzman, S. A.; Craig, M. A.; Renault, R. W.; Gautason, B.; Mountain, B.

    2013-01-01

    Hydrated silica-rich materials have recently been discovered on the surface of Mars by the Mars Exploration Rover (MER) Spirit, the Mars Reconnaissance Orbiter (MRO) Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), and the Mars Express Observatoire pour la Mineralogie, l'Eau, les Glaces, et l'Activite'(OMEGA) in several locations. Having been interpreted as hydrothermal deposits and aqueous alteration products, these materials have important implications for the history of water on the martian surface. Spectral detections of these materials in visible to near infrared (Vis NIR) wavelengths have been based on a H2O absorption feature in the 934-1009 nm region seen with Spirit s Pancam instrument, and on SiOH absorption features in the 2.21-2.26 micron range seen with CRISM. Our work aims to determine how the spectral reflectance properties of silica-rich materials in Vis NIR wavelengths vary as a function of environmental conditions and formation. Here we present laboratory reflectance spectra of a diverse suite of silica-rich materials (chert, opal, quartz, natural sinters and synthetic silica) under a range of grain sizes and temperature, pressure, and humidity conditions. We find that the H2O content and form of H2O/OH present in silica-rich materials can have significant effects on their Vis NIR spectra. Our main findings are that the position of the approx.1.4 microns OH feature and the symmetry of the approx.1.9 microns feature can be used to discern between various forms of silica-rich materials, and that the ratio of the approx.2.2 microns (SiOH) and approx.1.9 microns (H2O) band depths can aid in distinguishing between silica phases (opal-A vs. opal-CT) and formation conditions (low vs. high temperature). In a case study of hydrated silica outcrops in Valles Marineris, we show that careful application of a modified version of these spectral parameters to orbital near-infrared spectra (e.g., from CRISM and OMEGA) can aid in characterizing the

  9. Reflectance spectra diversity of silica-rich materials: Sensitivity to environment and implications for detections on Mars

    NASA Astrophysics Data System (ADS)

    Rice, M. S.; Cloutis, E. A.; Bell, J. F.; Bish, D. L.; Horgan, B. H.; Mertzman, S. A.; Craig, M. A.; Renaut, R. W.; Gautason, B.; Mountain, B.

    2013-03-01

    Hydrated silica-rich materials have recently been discovered on the surface of Mars by the Mars Exploration Rover (MER) Spirit, the Mars Reconnaissance Orbiter (MRO) Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), and the Mars Express Observatoire pour la Minéralogie, l’Eau, les Glaces, et l’Activité (OMEGA) in several locations. Having been interpreted as hydrothermal deposits and aqueous alteration products, these materials have important implications for the history of water on the martian surface. Spectral detections of these materials in visible to near infrared (Vis-NIR) wavelengths have been based on a H2O absorption feature in the 934-1009 nm region seen with Spirit’s Pancam instrument, and on SiOH absorption features in the 2.21-2.26 μm range seen with CRISM. Our work aims to determine how the spectral reflectance properties of silica-rich materials in Vis-NIR wavelengths vary as a function of environmental conditions and formation. Here we present laboratory reflectance spectra of a diverse suite of silica-rich materials (chert, opal, quartz, natural sinters and synthetic silica) under a range of grain sizes and temperature, pressure, and humidity conditions. We find that the H2O content and form of H2O/OH present in silica-rich materials can have significant effects on their Vis-NIR spectra. Our main findings are that the position of the ∼1.4 μm OH feature and the symmetry of the ∼1.9 μm feature can be used to discern between various forms of silica-rich materials, and that the ratio of the ∼2.2 μm (SiOH) and ∼1.9 μm (H2O) band depths can aid in distinguishing between silica phases (opal-A vs. opal-CT) and formation conditions (low vs. high temperature). In a case study of hydrated silica outcrops in Valles Marineris, we show that careful application of a modified version of these spectral parameters to orbital near-infrared spectra (e.g., from CRISM and OMEGA) can aid in characterizing the compositional diversity of

  10. Reflectance Spectra Diversity of Silica-Rich Materials: Sensitivity to Environment and Implications for Detections on Mars

    NASA Technical Reports Server (NTRS)

    Rice, M. S.; Cloutis, E. A.; Bell, J. F., III; Bish, D. L.; Horgan, B. H.; Mertzman, S. A.; Craig, M. A.; Renault, R. W.; Gautason, B.; Mountain, B.

    2013-01-01

    Hydrated silica-rich materials have recently been discovered on the surface of Mars by the Mars Exploration Rover (MER) Spirit, the Mars Reconnaissance Orbiter (MRO) Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), and the Mars Express Observatoire pour la Mineralogie, l'Eau, les Glaces, et l'Activite'(OMEGA) in several locations. Having been interpreted as hydrothermal deposits and aqueous alteration products, these materials have important implications for the history of water on the martian surface. Spectral detections of these materials in visible to near infrared (Vis NIR) wavelengths have been based on a H2O absorption feature in the 934-1009 nm region seen with Spirit s Pancam instrument, and on SiOH absorption features in the 2.21-2.26 micron range seen with CRISM. Our work aims to determine how the spectral reflectance properties of silica-rich materials in Vis NIR wavelengths vary as a function of environmental conditions and formation. Here we present laboratory reflectance spectra of a diverse suite of silica-rich materials (chert, opal, quartz, natural sinters and synthetic silica) under a range of grain sizes and temperature, pressure, and humidity conditions. We find that the H2O content and form of H2O/OH present in silica-rich materials can have significant effects on their Vis NIR spectra. Our main findings are that the position of the approx.1.4 microns OH feature and the symmetry of the approx.1.9 microns feature can be used to discern between various forms of silica-rich materials, and that the ratio of the approx.2.2 microns (SiOH) and approx.1.9 microns (H2O) band depths can aid in distinguishing between silica phases (opal-A vs. opal-CT) and formation conditions (low vs. high temperature). In a case study of hydrated silica outcrops in Valles Marineris, we show that careful application of a modified version of these spectral parameters to orbital near-infrared spectra (e.g., from CRISM and OMEGA) can aid in characterizing the

  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. Site-specific immobilization of recombinant antibody fragments through material-binding peptides for the sensitive detection of antigens in enzyme immunoassays.

    PubMed

    Kumada, Yoichi

    2014-11-01

    The immobilization of an antibody is one of the key technologies that are used to enhance the sensitivity and efficiency of the detection of target molecules in immunodiagnosis and immunoseparation. Recombinant antibody fragments such as VHH, scFv and Fabs produced by microorganisms are the next generation of ligand antibodies as an alternative to conventional whole Abs due to a smaller size and the possibility of site-directed immobilization with uniform orientation and higher antigen-binding activity in the adsorptive state. For the achievement of site-directed immobilization, affinity peptides for a certain ligand molecule or solid support must be introduced to the recombinant antibody fragments. In this mini-review, immobilization technologies for the whole antibodies (whole Abs) and recombinant antibody fragments onto the surfaces of plastics are introduced. In particular, the focus here is on immobilization technologies of recombinant antibody fragments utilizing affinity peptide tags, which possesses strong binding affinity towards the ligand molecules. Furthermore, I introduced the material-binding peptides that are capable of direct recognition of the target materials. Preparation and immobilization strategies for recombinant antibody fragments linked to material-binding peptides (polystyrene-binding peptides (PS-tags) and poly (methyl methacrylate)-binding peptide (PMMA-tag)) are the focus here, and are based on the enhancement of sensitivity and a reduction in the production costs of ligand antibodies. This article is part of a Special Issue entitled: Recent advances in molecular engineering of antibody.

  13. Combination of the sensitivity in EM field and the optimum nonlinear interpolation approximation as a favorable means of CAD of composite meta-materials

    NASA Astrophysics Data System (ADS)

    Kida, Yuichi; Kida, Takuro

    2010-08-01

    In the iterative CAD design of new materials by digital computers, it is necessary to obtain the differential coefficients, that is, component-sensitivities caused by the small deviation of inner-components in a given electromagnetic field expressed by the Maxwell relations. Further, to determine the step-size of the numerical iterative CAD design that uses the discrete sample values of the wave form at the sample points with the same interval of the step-size, it is required to estimate the error favorably between the original wave form and its numerical approximation. In this paper, firstly, we present conservation operators in micro-electromagnetic field and its macro-expression in the electromagnetic field. Secondly, we present some concrete conservation operators and make clear that the certain quantities, such as the stored energy of a small inner-component in the closed electromagnetic field, are closely correlated to the differential coefficients of the electric field and the magnetic field observed at the outer ports. Secondly, in a single-mode electromagnetic field, we obtain the relation between the stored energy, and the component-sensitivities caused by the small deviation of the inner-component. Thirdly, we present a brief survey of the progress in the development of meta material and show the usefulness of combining the above results with the optimum nonlinear approximation in the iterative design of linear or nonlinear meta material.

  14. Lanthanide sensitization in II-VI semiconductor materials: a case study with terbium(III) and europium(III) in zinc sulfide nanoparticles.

    PubMed

    Mukherjee, Prasun; Shade, Chad M; Yingling, Adrienne M; Lamont, Daniel N; Waldeck, David H; Petoud, Stéphane

    2011-04-28

    This work explores the sensitization of luminescent lanthanide Tb(3+) and Eu(3+) cations by the electronic structure of zinc sulfide (ZnS) semiconductor nanoparticles. Excitation spectra collected while monitoring the lanthanide emission bands reveal that the ZnS nanoparticles act as an antenna for the sensitization of Tb(3+) and Eu(3+). The mechanism of lanthanide ion luminescence sensitization is rationalized in terms of an energy and charge transfer between trap sites and is based on a semiempirical model, proposed by Dorenbos and co-workers (Dorenbos, P. J. Phys.: Condens. Matter 2003, 15, 8417-8434; J. Lumin. 2004, 108, 301-305; J. Lumin. 2005, 111, 89-104. Dorenbos, P.; van der Kolk, E. Appl. Phys. Lett. 2006, 89, 061122-1-061122-3; Opt. Mater. 2008, 30, 1052-1057. Dorenbos, P. J. Alloys Compd. 2009, 488, 568-573; references 1-6.) to describe the energy level scheme. This model implies that the mechanisms of luminescence sensitization of Tb(3+) and Eu(3+) in ZnS nanoparticles are different; namely, Tb(3+) acts as a hole trap, whereas Eu(3+) acts as an electron trap. Further testing of this model is made by extending the studies from ZnS nanoparticles to other II-VI semiconductor materials; namely, CdSe, CdS, and ZnSe.

  15. Comparing the effect of a desensitizing material and a self-etch adhesive on dentin sensitivity after periodontal surgery: a randomized clinical trial.

    PubMed

    Hajizadeh, Hila; Nemati-Karimooy, Atefeh; Majidinia, Sara; Moeintaghavi, Amir; Ghavamnasiri, Marjaneh

    2017-08-01

    This double-blind randomized placebo-controlled clinical trial evaluated the ability of a desensitizing agent and a self-etch adhesive on cervical dentin sensitivity (CDS) after periodontal surgery. Ninety hypersensitive teeth of 13 subjects were included in the study. After periodontal surgery, the teeth of each posterior sextant treated with one of the following materials: G1: Clearfil S(3) Bond (Kuraray Dental), G2: Gluma Desensitizer (Heraeus Kulzer), and G3: placebo (water). The sensitivity was assessed using evaporative stimuli before treatment (baseline, T0), 1 day after treatment (T1), after 1 week (T2), and after 1 month (T3) according to visual analog scale (VAS). Following the treatment, all the 3 groups showed significant reduction of CDS in T1 compared to T0. Reduction of CDS between T1 and T2 was observed only in G1 but there was no significant difference between T2 and T3 in this group. Although we observed a significant difference in T3 compared to T1 and T2 in G2 and G3, comparison of treatment groups in each assessment time showed a significant difference only in T3. According to paired comparison, this was due to the difference between G2 and G3. Dentin sensitivity following periodontal surgery will decrease spontaneously over time, but treating the sensitive teeth with Gluma Desensitizer and Clearfil S(3) Bond can have some benefits.

  16. Lanthanide Sensitization in II–VI Semiconductor Materials: A Case Study with Terbium (III) and Europium (III) in Zinc Sulfide Nanoparticles

    PubMed Central

    Mukherjee, Prasun; Shade, Chad M.; Yingling, Adrienne M.; Lamont, Daniel N.; Waldeck, David H.; Petoud, Stéphane

    2010-01-01

    This work explores the sensitization of luminescent lanthanide Tb3+ and Eu3+ cations by the electronic structure of zinc sulfide (ZnS) semiconductor nanoparticles. Excitation spectra collected, while monitoring the lanthanide emission bands, reveals that the ZnS nanoparticles act as an antenna for the sensitization of Tb3+ and Eu3+. The mechanism of lanthanide ion luminescence sensitization is rationalized in terms of an energy and charge transfer between trap sites and is based on a semi-empirical model, proposed by Dorenbos and coworkers, 1–6 to describe the energy level scheme. This model implies that the mechanisms of luminescence sensitization of Tb3+ and Eu3+ in ZnS nanoparticles are different; namely Tb3+ acts as a hole trap, while Eu3+ acts as an electron trap. Further testing of this model is made by extending the studies from ZnS nanoparticles to other II–VI semiconductor materials; namely, CdSe, CdS, and ZnSe. PMID:21090795

  17. Graphdiyne: A Metal-Free Material as Hole Transfer Layer To Fabricate Quantum Dot-Sensitized Photocathodes for Hydrogen Production.

    PubMed

    Li, Jian; Gao, Xin; Liu, Bin; Feng, Qingliang; Li, Xu-Bing; Huang, Mao-Yong; Liu, Zhongfan; Zhang, Jin; Tung, Chen-Ho; Wu, Li-Zhu

    2016-03-30

    Graphdiyne (GDY), a novel large π-conjugated carbon material, for the first time, is introduced as the hole transfer layer into a photoelectrochemical water splitting cell (PEC). Raman and ultraviolet photoelectron spectroscopic studies indicate the existence of relatively strong π-π interactions between GDY and 4-mercaptopyridine surface-functionalized CdSe quantum dots, beneficial to the hole transportation and enhancement of the photocurrent performance. Upon exposure to a Xe lamp, the integrated photocathode produces a current density of nearly -70 μA cm(-2) at a potential of 0 V vs NHE in neutral aqueous solution. Simultaneously, the photocathode evolves H2 with 90 ± 5% faradic efficiency over three times and exhibits good stability within 12 h. All of the results indicate that GDY is a promising hole transfer material to fabricate a PEC device for water splitting by solar energy.

  18. Development of cholesterol biosensor with high sensitivity using dual-enzyme immobilization into the mesoporous silica materials

    NASA Astrophysics Data System (ADS)

    Murai, Kazuki; Kato, Katsuya

    2011-12-01

    Mesoporous silica (MPS) materials with different pore diameters were synthesized by a sol-gel method where organic templates such as cationic surfactant (cetyltrimethylammonium bromide) and triblock co-polymer of (poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) (Pluronic P123, EO 20PO 70EO 20)), were used. MPS surface was organo-functionalized using a silane coupling reagent (ethyl-, phenyl-, or 3-mercaptpropyltriethoxysilane). Dual-enzyme, cholesterol esterase (10.0 nm × 5.4 nm × 11.0 nm) and cholesterol oxidase (6.8 nm × 8.5 nm × 8.8 nm), was immobilized on MPS materials by physical adsorption. Amount of dual-enzyme immobilized on all MPS materials, having a different pore size (2.7, 6.4, 12.4, 14.7, and 22.6 nm), and organo-functionalized MPS was similar (CE: 1.5 mg/mg silica and CO: 0.01 mg/mg silica). High activity of dual-enzyme was obtained by adjacently immobilizing on MPS materials. Its activity on MPS-2 (pore diameter: 6.4 nm) or MPS-5 (pore diameter: 22.6 nm) showed approximately 60% of native activity. Moreover, dual-enzyme immobilized on MPS with highly hydrophobic organo-functional groups (phenyl- or mercaptopropyl-group) exhibited higher activity than that on no-substituted MPS. Relative activity of dual-enzyme immobilized on organo-functionalized MPS-2 increased from 58% to 93%, under the optimum conditions.

  19. Analysis of sensitivity enhancement by dynamic nuclear polarization in solid-state NMR: a case study of functionalized mesoporous materials.

    PubMed

    Kobayashi, Takeshi; Lafon, Olivier; Thankamony, Aany S Lilly; Slowing, Igor I; Kandel, Kapil; Carnevale, Diego; Vitzthum, Veronika; Vezin, Hervé; Amoureux, Jean-Paul; Bodenhausen, Geoffrey; Pruski, Marek

    2013-04-21

    We systematically studied the enhancement factor (per scan) and the sensitivity enhancement (per unit time) in (13)C and (29)Si cross-polarization magic angle spinning (CP-MAS) NMR boosted by dynamic nuclear polarization (DNP) of functionalized mesoporous silica nanoparticles (MSNs). Specifically, we separated contributions due to: (i) microwave irradiation, (ii) quenching by paramagnetic effects, (iii) the presence of frozen solvent, (iv) the temperature, as well as changes in (v) relaxation and (vi) cross-polarization behaviour. No line-broadening effects were observed for MSNs when lowering the temperature from 300 to 100 K. Notwithstanding a significant signal reduction due to quenching by TOTAPOL radicals, DNP-CP-MAS at 100 K provided global sensitivity enhancements of 23 and 45 for (13)C and (29)Si, respectively, relative to standard CP-MAS measurements at room temperature. The effects of DNP were also ascertained by comparing with state-of-the-art two-dimensional heteronuclear (1)H{(13)C} and (29)Si{(1)H} correlation spectra, using, respectively, indirect detection or Carr-Purcell-Meiboom-Gill (CPMG) refocusing to boost signal acquisition. This study highlights opportunities for further improvements through the development of high-field DNP, better polarizing agents, and improved capabilities for low-temperature MAS.

  20. Hole transport materials with low glass transition temperatures and high solubility for application in solid-state dye-sensitized solar cells.

    PubMed

    Leijtens, Tomas; Ding, I-Kang; Giovenzana, Tommaso; Bloking, Jason T; McGehee, Michael D; Sellinger, Alan

    2012-02-28

    We present the synthesis and device characterization of new hole transport materials (HTMs) for application in solid-state dye-sensitized solar cells (ssDSSCs). In addition to possessing electrical properties well suited for ssDSSCs, these new HTMs have low glass transition temperatures, low melting points, and high solubility, which make them promising candidates for increased pore filling into mesoporous titania films. Using standard device fabrication methods and Z907 as the sensitizing dye, power conversion efficiencies (PCE) of 2.94% in 2-μm-thick cells were achieved, rivaling the PCE obtained by control devices using the state-of-the-art HTM spiro-OMeTAD. In 6-μm-thick cells, the device performance is shown to be higher than that obtained using spiro-OMeTAD, making these new HTMs promising for preparing high-efficiency ssDSSCs.

  1. A Generalized Anisotropic Hardening Rule Based on the Mroz Multi-Yield-Surface Model for Pressure Insensitive and Sensitive Materials

    SciTech Connect

    Choi, Kyoo Sil; Pan, Jwo

    2009-07-27

    In this paper, a generalized anisotropic hardening rule based on the Mroz multi-yield-surface model is derived. The evolution equation for the active yield surface is obtained by considering the continuous expansion of the active yield surface during the unloading/reloading process. The incremental constitutive relation based on the associated flow rule is then derived for a general yield function. As a special case, detailed incremental constitutive relations are derived for the Mises yield function. The closed-form solutions for one-dimensional stress-plastic strain curves are also derived and plotted for the Mises materials under cyclic loading conditions. The stress-plastic strain curves show closed hysteresis loops under uniaxial cyclic loading conditions and the Masing hypothesis is applicable. A user material subroutine based on the Mises yield function, the anisotropic hardening rule and the constitutive relations was then written and implemented into ABAQUS. Computations were conducted for a simple plane strain finite element model under uniaxial monotonic and cyclic loading conditions based on the anisotropic hardening rule and the isotropic and nonlinear kinematic hardening rules of ABAQUS. The results indicate that the plastic response of the material follows the intended input stress-strain data for the anisotropic hardening rule whereas the plastic response depends upon the input strain ranges of the stress-strain data for the nonlinear kinematic hardening rule.

  2. Foreword: Biomonitoring Equivalents special issue.

    PubMed

    Meek, M E; Sonawane, B; Becker, R A

    2008-08-01

    The challenge of interpreting results of biomonitoring for environmental chemicals in humans is highlighted in this Foreword to the Biomonitoring Equivalents (BEs) special issue of Regulatory Toxicology and Pharmacology. There is a pressing need to develop risk-based tools in order to empower scientists and health professionals to interpret and communicate the significance of human biomonitoring data. The BE approach, which integrates dosimetry and risk assessment methods, represents an important advancement on the path toward achieving this objective. The articles in this issue, developed as a result of an expert panel meeting, present guidelines for derivation of BEs, guidelines for communication using BEs and several case studies illustrating application of the BE approach for specific substances.

  3. Equivalent damage: A critical assessment

    NASA Technical Reports Server (NTRS)

    Laflen, J. H.; Cook, T. S.

    1982-01-01

    The overall goal of achieving improved life cycle management of aircraft engine, gas turbine components is a major industry thrust. Low cycle fatigue (LCF) crack initiation prediction, an important element of life cycle management as traditionally applied, may be overly conservative in estimating total cyclic life capability. Consequently, there is increasing pressure to improve predictive methods both for crack initiation and for subsequent crack propagation. The utility of equivalent damage concepts for application to hot section components of aircraft engines was studied. Specifically, the topics examined were mean stress, cumulative damage, and multiaxiality. Other factors inherently linked to this study were the basic formulation of damage parameters at elevated temperatures and the fact that hot section components experience severe temperature fluctuations throughout their service lifetime.

  4. Equivalent crystal theory of alloys

    NASA Technical Reports Server (NTRS)

    Bozzolo, Guillermo; Ferrante, John

    1991-01-01

    Equivalent Crystal Theory (ECT) is a new, semi-empirical approach to calculating the energetics of a solid with defects. The theory has successfully reproduced surface energies in metals and semiconductors. The theory of binary alloys to date, both with first-principles and semi-empirical models, has not been very successful in predicting the energetics of alloys. This procedure is used to predict the heats of formation, cohesive energy, and lattice parameter of binary alloys of Cu, Ni, Al, Ag, Au, Pd, and Pt as functions of composition. The procedure accurately reproduces the heats of formation versus composition curves for a variety of binary alloys. The results are then compared with other approaches such as the embedded atom and lattice parameters of alloys from pure metal properties more accurately than Vegard's law is presented.

  5. Apparatus for Teaching Physics. Mechanical Equivalent of Heat.

    ERIC Educational Resources Information Center

    Inscho, F. Paul

    1992-01-01

    Suggests an apparatus to improve the measurement of the mechanical equivalent of heat. Describes the materials needed to construct the apparatus; the methodology of an experiment to measure the heat gained by lead shot falling through a distance of 100 meters; and the calculations made to register that gain. (MDH)

  6. Advanced Life Support Equivalent System Mass Guidelines Document

    NASA Technical Reports Server (NTRS)

    Levri, Julie; Fisher, John W.; Jones, Harry W.; Drysdale, Alan E.; Ewert, Michael K.; Hanford, Anthony J.; Hogan, John A.; Joshi, Jitendri, A.; Vaccari, David A.

    2003-01-01

    This document is a viewgraph presentation which provides guidelines for performing an Equivalent System Mass (ESM) evaluation for trade study purposes. The document: 1) Defines ESM; 2) Explains how to calculate ESM; 3) Discusses interpretation of ESM results. The document is designed to provide detailed instructive material for researchers who are performing ESM evaluations for the first time.

  7. A Passive Thermal Carrier (LoTEC(c )) for Temperature Sensitive Materials Being Moved to and From ISS and for Shuttle (STS) Flights

    NASA Astrophysics Data System (ADS)

    Wessling, F. C.; Blackwood, J. M.; Holt, H. R.

    2002-01-01

    the use of power for transporting temperature sensitive materials to and from the International Space Station. LoTEC uses a combination of high thermal resistance insulation, careful thermal design and phase change materials to maintain temperature. It has been tested with phase change materials for three different interior temperatures (-16C, 0C, +4C). These temperatures are usable for preservation of many biological materials during transport. The exterior dimensions of LoTEC are approximately 250.7 x 436.9 x 514.1 mm. Thus, LoTEC fits into a standard mid-deck locker, an Express Rack, a SpaceHab rack or a rack in the Multi-Purpose Logistics Module (MPLM). LoTEC has an empty mass of approximately 9.6 kg and an internal volume of 22 Liters. This volume is reduced by the amount and type of phase change material (PCM) used. For example, eight kg of water ice and its containers would take up approximately half of the internal volume, leaving 11 Liters of space for the payload. Several different configurations have been considered to accommodate different payload dimensions.The interior dimensions of LoTEC are approximately 406 x 343 x 158 mm. Measured energy gain by LoTEC is approximately 0.14 watts per degrees Celsius. Performance data in the form of temperature versus time curves are included. Eight kg of PCM gives approximately eight days of constant temperature at typical STS interior temperatures. The temperature distribution in LoTEC is dependent on the PCM containers, the PCM used, and the location of the containers in LoTEC. Small, stand-alone data loggers record the temperatures. Refreezing of phase change materials depends on the facilities on board the ISS or the STS. Various methods of refreezing of phase change materials on the ISS are discussed.

  8. Application of Adjoint Methodology to Supersonic Aircraft Design Using Reversed Equivalent Areas

    NASA Technical Reports Server (NTRS)

    Rallabhandi, Sriram K.

    2013-01-01

    This paper presents an approach to shape an aircraft to equivalent area based objectives using the discrete adjoint approach. Equivalent areas can be obtained either using reversed augmented Burgers equation or direct conversion of off-body pressures into equivalent area. Formal coupling with CFD allows computation of sensitivities of equivalent area objectives with respect to aircraft shape parameters. The exactness of the adjoint sensitivities is verified against derivatives obtained using the complex step approach. This methodology has the benefit of using designer-friendly equivalent areas in the shape design of low-boom aircraft. Shape optimization results with equivalent area cost functionals are discussed and further refined using ground loudness based objectives.

  9. A Highly Sensitive Assay Using Synthetic Blood Containing Test Microbes for Evaluation of the Penetration Resistance of Protective Clothing Material under Applied Pressure.

    PubMed

    Shimasaki, Noriko; Hara, Masayuki; Kikuno, Ritsuko; Shinohara, Katsuaki

    2016-01-01

    To prevent nosocomial infections caused by even either Ebola virus or methicillin-resistant Staphylococcus aureus (MRSA), healthcare workers must wear the appropriate protective clothing which can inhibit contact transmission of these pathogens. Therefore, it is necessary to evaluate the performance of protective clothing for penetration resistance against infectious agents. In Japan, some standard methods were established to evaluate the penetration resistance of protective clothing fabric materials under applied pressure. However, these methods only roughly classified the penetration resistance of fabrics, and the detection sensitivity of the methods and the penetration amount with respect to the relationship between blood and the pathogen have not been studied in detail. Moreover, no standard method using bacteria for evaluation is known. Here, to evaluate penetration resistance of protective clothing materials under applied pressure, the detection sensitivity and the leak amount were investigated by using synthetic blood containing bacteriophage phi-X174 or S. aureus. And the volume of leaked synthetic blood and the amount of test microbe penetration were simultaneously quantified. Our results showed that the penetration detection sensitivity achieved using a test microbial culture was higher than that achieved using synthetic blood at invisible leak level pressures. This finding suggested that there is a potential risk of pathogen penetration even when visual leak of contaminated blood through the protective clothing was not observed. Moreover, at visible leak level pressures, it was found that the amount of test microbe penetration varied at least ten-fold among protective clothing materials classified into the same class of penetration resistance. Analysis of the penetration amount revealed a significant correlation between the volume of penetrated synthetic blood and the amount of test microbe penetration, indicating that the leaked volume of synthetic

  10. A Rapid and Sensitive Strip-Based Quick Test for Nerve Agents Tabun, Sarin, and Soman Using BODIPY-Modified Silica Materials.

    PubMed

    Climent, Estela; Biyikal, Mustafa; Gawlitza, Kornelia; Dropa, Tomáš; Urban, Martin; Costero, Ana M; Martínez-Máñez, Ramón; Rurack, Knut

    2016-08-01

    Test strips that in combination with a portable fluorescence reader or digital camera can rapidly and selectively detect chemical warfare agents (CWAs) such as Tabun (GA), Sarin (GB), and Soman (GD) and their simulants in the gas phase have been developed. The strips contain spots of a hybrid indicator material consisting of a fluorescent BODIPY indicator covalently anchored into the channels of mesoporous SBA silica microparticles. The fluorescence quenching response allows the sensitive detection of CWAs in the μg m(-3) range in a few seconds.

  11. Carbazole-based hole-transport materials for efficient solid-state dye-sensitized solar cells and perovskite solar cells.

    PubMed

    Xu, Bo; Sheibani, Esmaeil; Liu, Peng; Zhang, Jinbao; Tian, Haining; Vlachopoulos, Nick; Boschloo, Gerrit; Kloo, Lars; Hagfeldt, Anders; Sun, Licheng

    2014-10-01

    Two carbazole-based small molecule hole-transport materials (HTMs) are synthesized and investigated in solid-state dye-sensitized solar cells (ssDSCs) and perovskite solar cells (PSCs). The HTM X51-based devices exhibit high power conversion efficiencies (PCEs) of 6.0% and 9.8% in ssDSCs and PSCs, respectively. These results are superior or comparable to those of 5.5% and 10.2%, respectively, obtained for the analogous cells using the state-of-the-art HTM Spiro-OMeTAD. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Equivalent-Continuum Modeling With Application to Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Odegard, Gregory M.; Gates, Thomas S.; Nicholson, Lee M.; Wise, Kristopher E.

    2002-01-01

    A method has been proposed for developing structure-property relationships of nano-structured materials. This method serves as a link between computational chemistry and solid mechanics by substituting discrete molecular structures with equivalent-continuum models. It has been shown that this substitution may be accomplished by equating the vibrational potential energy of a nano-structured material with the strain energy of representative truss and continuum models. As important examples with direct application to the development and characterization of single-walled carbon nanotubes and the design of nanotube-based devices, the modeling technique has been applied to determine the effective-continuum geometry and bending rigidity of a graphene sheet. A representative volume element of the chemical structure of graphene has been substituted with equivalent-truss and equivalent continuum models. As a result, an effective thickness of the continuum model has been determined. This effective thickness has been shown to be significantly larger than the interatomic spacing of graphite. The effective thickness has been shown to be significantly larger than the inter-planar spacing of graphite. The effective bending rigidity of the equivalent-continuum model of a graphene sheet was determined by equating the vibrational potential energy of the molecular model of a graphene sheet subjected to cylindrical bending with the strain energy of an equivalent continuum plate subjected to cylindrical bending.

  13. The Synthesis and Photophysical Characterization of Porphyrin Photoactive Materials for Use as Sensitizers in Organic Photovoltaics and Photodynamic Therapy

    NASA Astrophysics Data System (ADS)

    Marin, Dawn Marie

    Solar energy conversion and photodynamic therapy (PDT) are very different applications. However, both utilize very similar photoactive molecules called porphyrins. Porphyrins are structural analogs of chlorophyll and also function as prosthetic groups in some biological enzymes. Understanding the structure/function relationship of these molecules is crucial for enhancing the energy generation efficiency of molecular solar cells and improving chemotherapeutic activity in PDT. In this dissertation, two approaches were applied with the goal of increasing the efficiency of molecular semiconductors for these applications: the heavy atom effect and donor-acceptor molecules. We enhanced the efficiency of triplet excited state formation and singlet oxygen generation for porphyrin sensitizers using the heavy atom effect. The heavy atom effect induces spin-orbit coupling to promote intersystem crossing into the triplet state. In this study, a carbomethoxyphenyl substituent was replaced with either a bromophenyl or an iodophenyl substituent on 5,10,15,20-tetrakis(4-carbomethoxyphenyl)porphyrin. The longer lifetimes obtained from the increase in the triplet excited state allow for longer exciton diffusion lengths and lower recombination rates in photovoltaics. Also, the enhanced intersystem crossing is beneficial for photodynamic therapy because it increases singlet oxygen generation, which destroys tumor cells. Optimizing photovoltaic performance and PDT efficacy can also be accomplished with donor-acceptor molecules because they have extended electronic pi bond delocalization across the molecule, which causes the molecule to absorb longer wavelengths of light. Donor-acceptor molecules should produce photovoltaic devices that absorb more of the solar spectrum and produce sensitizers that absorb wavelengths of light that can penetrate through tissues. Donor-acceptor molecules were synthesized using 5,15-bis(4-carbomethoxyphenyl)porphyrin as the acceptor and thiazolo[5,4-d

  14. 46 CFR 110.20-1 - Equivalents.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Equivalents. 110.20-1 Section 110.20-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING GENERAL PROVISIONS Equivalents... engineering evaluations and tests to demonstrate the equivalence of the substitute. ...

  15. Stimulus Equivalence: Testing Sidman's (2000) Theory

    ERIC Educational Resources Information Center

    Minster, Sara Tepaeru; Jones, Max; Elliffe, Douglas; Muthukumaraswamy, Suresh D.

    2006-01-01

    Sidman's (2000) theory regarding the origin of equivalence relations predicts that a reinforcing stimulus common to distinct equivalence classes must drop out of the equivalence relations. This prediction was tested in the present study by arranging class-specific reinforcers, R1 and R2, following correct responding on the prerequisite conditional…

  16. 46 CFR 110.20-1 - Equivalents.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Equivalents. 110.20-1 Section 110.20-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING GENERAL PROVISIONS Equivalents... engineering evaluations and tests to demonstrate the equivalence of the substitute. ...

  17. 46 CFR 110.20-1 - Equivalents.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Equivalents. 110.20-1 Section 110.20-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING GENERAL PROVISIONS Equivalents... engineering evaluations and tests to demonstrate the equivalence of the substitute. ...

  18. 46 CFR 110.20-1 - Equivalents.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Equivalents. 110.20-1 Section 110.20-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING GENERAL PROVISIONS Equivalents... engineering evaluations and tests to demonstrate the equivalence of the substitute. ...

  19. 46 CFR 110.20-1 - Equivalents.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Equivalents. 110.20-1 Section 110.20-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING GENERAL PROVISIONS Equivalents... engineering evaluations and tests to demonstrate the equivalence of the substitute. ...

  20. 21 CFR 26.6 - Equivalence assessment.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Equivalence assessment. 26.6 Section 26.6 Food and... Specific Sector Provisions for Pharmaceutical Good Manufacturing Practices § 26.6 Equivalence assessment... or processes. (c) The equivalence assessment shall include information exchanges (including...